Gitiles
Code Review Sign In
review.shift-gmbh.com / SHIFTPHONES / android_art / ddf4fd3c37af160b5a1f7e83212b837f50e13e81 / . / runtime / class_linker.cc
blob: 5410bb027d2f15741825d0c602959b4b5e5db18c [file] [log] [blame]
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "class_linker.h"
#include <unistd.h>
#include <algorithm>
#include <deque>
#include <forward_list>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <string>
#include <string_view>
#include <tuple>
#include <utility>
#include <vector>
#include "android-base/stringprintf.h"
#include "art_field-inl.h"
#include "art_method-inl.h"
#include "barrier.h"
#include "base/arena_allocator.h"
#include "base/casts.h"
#include "base/file_utils.h"
#include "base/hash_map.h"
#include "base/hash_set.h"
#include "base/leb128.h"
#include "base/logging.h"
#include "base/metrics/metrics.h"
#include "base/mutex-inl.h"
#include "base/os.h"
#include "base/quasi_atomic.h"
#include "base/scoped_arena_containers.h"
#include "base/scoped_flock.h"
#include "base/stl_util.h"
#include "base/string_view_cpp20.h"
#include "base/systrace.h"
#include "base/time_utils.h"
#include "base/unix_file/fd_file.h"
#include "base/utils.h"
#include "base/value_object.h"
#include "cha.h"
#include "class_linker-inl.h"
#include "class_loader_utils.h"
#include "class_root-inl.h"
#include "class_table-inl.h"
#include "compiler_callbacks.h"
#include "debug_print.h"
#include "debugger.h"
#include "dex/class_accessor-inl.h"
#include "dex/descriptors_names.h"
#include "dex/dex_file-inl.h"
#include "dex/dex_file_exception_helpers.h"
#include "dex/dex_file_loader.h"
#include "dex/signature-inl.h"
#include "dex/utf.h"
#include "entrypoints/entrypoint_utils-inl.h"
#include "entrypoints/runtime_asm_entrypoints.h"
#include "experimental_flags.h"
#include "gc/accounting/card_table-inl.h"
#include "gc/accounting/heap_bitmap-inl.h"
#include "gc/accounting/space_bitmap-inl.h"
#include "gc/heap-visit-objects-inl.h"
#include "gc/heap.h"
#include "gc/scoped_gc_critical_section.h"
#include "gc/space/image_space.h"
#include "gc/space/space-inl.h"
#include "gc_root-inl.h"
#include "handle_scope-inl.h"
#include "hidden_api.h"
#include "image-inl.h"
#include "imt_conflict_table.h"
#include "imtable-inl.h"
#include "intern_table-inl.h"
#include "interpreter/interpreter.h"
#include "interpreter/mterp/nterp.h"
#include "jit/debugger_interface.h"
#include "jit/jit.h"
#include "jit/jit_code_cache.h"
#include "jni/java_vm_ext.h"
#include "jni/jni_internal.h"
#include "linear_alloc.h"
#include "mirror/array-alloc-inl.h"
#include "mirror/array-inl.h"
#include "mirror/call_site.h"
#include "mirror/class-alloc-inl.h"
#include "mirror/class-inl.h"
#include "mirror/class.h"
#include "mirror/class_ext.h"
#include "mirror/class_loader.h"
#include "mirror/dex_cache-inl.h"
#include "mirror/dex_cache.h"
#include "mirror/emulated_stack_frame.h"
#include "mirror/field.h"
#include "mirror/iftable-inl.h"
#include "mirror/method.h"
#include "mirror/method_handle_impl.h"
#include "mirror/method_handles_lookup.h"
#include "mirror/method_type.h"
#include "mirror/object-inl.h"
#include "mirror/object-refvisitor-inl.h"
#include "mirror/object.h"
#include "mirror/object_array-alloc-inl.h"
#include "mirror/object_array-inl.h"
#include "mirror/object_array.h"
#include "mirror/object_reference.h"
#include "mirror/object_reference-inl.h"
#include "mirror/proxy.h"
#include "mirror/reference-inl.h"
#include "mirror/stack_trace_element.h"
#include "mirror/string-inl.h"
#include "mirror/throwable.h"
#include "mirror/var_handle.h"
#include "native/dalvik_system_DexFile.h"
#include "nativehelper/scoped_local_ref.h"
#include "nterp_helpers.h"
#include "oat.h"
#include "oat_file-inl.h"
#include "oat_file.h"
#include "oat_file_assistant.h"
#include "oat_file_manager.h"
#include "object_lock.h"
#include "profile/profile_compilation_info.h"
#include "runtime.h"
#include "runtime_callbacks.h"
#include "scoped_thread_state_change-inl.h"
#include "thread-inl.h"
#include "thread.h"
#include "thread_list.h"
#include "trace.h"
#include "transaction.h"
#include "vdex_file.h"
#include "verifier/class_verifier.h"
#include "verifier/verifier_deps.h"
#include "well_known_classes.h"
namespace art {
using android::base::StringPrintf;
static constexpr bool kCheckImageObjects = kIsDebugBuild;
static constexpr bool kVerifyArtMethodDeclaringClasses = kIsDebugBuild;
static void ThrowNoClassDefFoundError(const char* fmt, ...)
__attribute__((__format__(__printf__, 1, 2)))
REQUIRES_SHARED(Locks::mutator_lock_);
static void ThrowNoClassDefFoundError(const char* fmt, ...) {
va_list args;
va_start(args, fmt);
Thread* self = Thread::Current();
self->ThrowNewExceptionV("Ljava/lang/NoClassDefFoundError;", fmt, args);
va_end(args);
}
static ObjPtr<mirror::Object> GetErroneousStateError(ObjPtr<mirror::Class> c)
REQUIRES_SHARED(Locks::mutator_lock_) {
ObjPtr<mirror::ClassExt> ext(c->GetExtData());
if (ext == nullptr) {
return nullptr;
} else {
return ext->GetErroneousStateError();
}
}
static bool IsVerifyError(ObjPtr<mirror::Object> obj)
REQUIRES_SHARED(Locks::mutator_lock_) {
// This is slow, but we only use it for rethrowing an error, and for DCHECK.
return obj->GetClass()->DescriptorEquals("Ljava/lang/VerifyError;");
}
// Helper for ThrowEarlierClassFailure. Throws the stored error.
static void HandleEarlierErroneousStateError(Thread* self,
ClassLinker* class_linker,
ObjPtr<mirror::Class> c)
REQUIRES_SHARED(Locks::mutator_lock_) {
ObjPtr<mirror::Object> obj = GetErroneousStateError(c);
DCHECK(obj != nullptr);
self->AssertNoPendingException();
DCHECK(!obj->IsClass());
ObjPtr<mirror::Class> throwable_class = GetClassRoot<mirror::Throwable>(class_linker);
ObjPtr<mirror::Class> error_class = obj->GetClass();
CHECK(throwable_class->IsAssignableFrom(error_class));
self->SetException(obj->AsThrowable());
self->AssertPendingException();
}
static void ChangeInterpreterBridgeToNterp(ArtMethod* method, ClassLinker* class_linker)
REQUIRES_SHARED(Locks::mutator_lock_) {
Runtime* runtime = Runtime::Current();
if (class_linker->IsQuickToInterpreterBridge(method->GetEntryPointFromQuickCompiledCode()) &&
CanMethodUseNterp(method)) {
if (method->GetDeclaringClass()->IsVisiblyInitialized() ||
!NeedsClinitCheckBeforeCall(method)) {
runtime->GetInstrumentation()->UpdateMethodsCode(method, interpreter::GetNterpEntryPoint());
} else {
// Put the resolution stub, which will initialize the class and then
// call the method with nterp.
runtime->GetInstrumentation()->UpdateMethodsCode(method, GetQuickResolutionStub());
}
}
}
static void UpdateClassAfterVerification(Handle<mirror::Class> klass,
PointerSize pointer_size,
verifier::FailureKind failure_kind)
REQUIRES_SHARED(Locks::mutator_lock_) {
Runtime* runtime = Runtime::Current();
ClassLinker* class_linker = runtime->GetClassLinker();
if (failure_kind == verifier::FailureKind::kNoFailure) {
klass->SetSkipAccessChecksFlagOnAllMethods(pointer_size);
}
// Now that the class has passed verification, try to set nterp entrypoints
// to methods that currently use the switch interpreter.
if (interpreter::CanRuntimeUseNterp()) {
for (ArtMethod& m : klass->GetMethods(pointer_size)) {
ChangeInterpreterBridgeToNterp(&m, class_linker);
}
}
}
// Callback responsible for making a batch of classes visibly initialized
// after all threads have called it from a checkpoint, ensuring visibility.
class ClassLinker::VisiblyInitializedCallback final
: public Closure, public IntrusiveForwardListNode<VisiblyInitializedCallback> {
public:
explicit VisiblyInitializedCallback(ClassLinker* class_linker)
: class_linker_(class_linker),
num_classes_(0u),
thread_visibility_counter_(0),
barriers_() {
std::fill_n(classes_, kMaxClasses, nullptr);
}
bool IsEmpty() const {
DCHECK_LE(num_classes_, kMaxClasses);
return num_classes_ == 0u;
}
bool IsFull() const {
DCHECK_LE(num_classes_, kMaxClasses);
return num_classes_ == kMaxClasses;
}
void AddClass(Thread* self, ObjPtr<mirror::Class> klass) REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK_EQ(klass->GetStatus(), ClassStatus::kInitialized);
DCHECK(!IsFull());
classes_[num_classes_] = self->GetJniEnv()->GetVm()->AddWeakGlobalRef(self, klass);
++num_classes_;
}
void AddBarrier(Barrier* barrier) {
barriers_.push_front(barrier);
}
std::forward_list<Barrier*> GetAndClearBarriers() {
std::forward_list<Barrier*> result;
result.swap(barriers_);
result.reverse(); // Return barriers in insertion order.
return result;
}
void MakeVisible(Thread* self) {
DCHECK_EQ(thread_visibility_counter_.load(std::memory_order_relaxed), 0);
size_t count = Runtime::Current()->GetThreadList()->RunCheckpoint(this);
AdjustThreadVisibilityCounter(self, count);
}
void Run(Thread* self) override {
self->ClearMakeVisiblyInitializedCounter();
AdjustThreadVisibilityCounter(self, -1);
}
private:
void AdjustThreadVisibilityCounter(Thread* self, ssize_t adjustment) {
ssize_t old = thread_visibility_counter_.fetch_add(adjustment, std::memory_order_relaxed);
if (old + adjustment == 0) {
// All threads passed the checkpoint. Mark classes as visibly initialized.
{
ScopedObjectAccess soa(self);
StackHandleScope<1u> hs(self);
MutableHandle<mirror::Class> klass = hs.NewHandle<mirror::Class>(nullptr);
JavaVMExt* vm = self->GetJniEnv()->GetVm();
for (size_t i = 0, num = num_classes_; i != num; ++i) {
klass.Assign(ObjPtr<mirror::Class>::DownCast(self->DecodeJObject(classes_[i])));
vm->DeleteWeakGlobalRef(self, classes_[i]);
if (klass != nullptr) {
mirror::Class::SetStatus(klass, ClassStatus::kVisiblyInitialized, self);
class_linker_->FixupStaticTrampolines(self, klass.Get());
}
}
num_classes_ = 0u;
}
class_linker_->VisiblyInitializedCallbackDone(self, this);
}
}
static constexpr size_t kMaxClasses = 16;
ClassLinker* const class_linker_;
size_t num_classes_;
jweak classes_[kMaxClasses];
// The thread visibility counter starts at 0 and it is incremented by the number of
// threads that need to run this callback (by the thread that request the callback
// to be run) and decremented once for each `Run()` execution. When it reaches 0,
// whether after the increment or after a decrement, we know that `Run()` was executed
// for all threads and therefore we can mark the classes as visibly initialized.
std::atomic<ssize_t> thread_visibility_counter_;
// List of barries to `Pass()` for threads that wait for the callback to complete.
std::forward_list<Barrier*> barriers_;
};
void ClassLinker::MakeInitializedClassesVisiblyInitialized(Thread* self, bool wait) {
if (kRuntimeISA == InstructionSet::kX86 || kRuntimeISA == InstructionSet::kX86_64) {
return; // Nothing to do. Thanks to the x86 memory model classes skip the initialized status.
}
std::optional<Barrier> maybe_barrier; // Avoid constructing the Barrier for `wait == false`.
if (wait) {
maybe_barrier.emplace(0);
}
int wait_count = 0;
VisiblyInitializedCallback* callback = nullptr;
{
MutexLock lock(self, visibly_initialized_callback_lock_);
if (visibly_initialized_callback_ != nullptr && !visibly_initialized_callback_->IsEmpty()) {
callback = visibly_initialized_callback_.release();
running_visibly_initialized_callbacks_.push_front(*callback);
}
if (wait) {
DCHECK(maybe_barrier.has_value());
Barrier* barrier = std::addressof(*maybe_barrier);
for (VisiblyInitializedCallback& cb : running_visibly_initialized_callbacks_) {
cb.AddBarrier(barrier);
++wait_count;
}
}
}
if (callback != nullptr) {
callback->MakeVisible(self);
}
if (wait_count != 0) {
DCHECK(maybe_barrier.has_value());
maybe_barrier->Increment(self, wait_count);
}
}
void ClassLinker::VisiblyInitializedCallbackDone(Thread* self,
VisiblyInitializedCallback* callback) {
MutexLock lock(self, visibly_initialized_callback_lock_);
// Pass the barriers if requested.
for (Barrier* barrier : callback->GetAndClearBarriers()) {
barrier->Pass(self);
}
// Remove the callback from the list of running callbacks.
auto before = running_visibly_initialized_callbacks_.before_begin();
auto it = running_visibly_initialized_callbacks_.begin();
DCHECK(it != running_visibly_initialized_callbacks_.end());
while (std::addressof(*it) != callback) {
before = it;
++it;
DCHECK(it != running_visibly_initialized_callbacks_.end());
}
running_visibly_initialized_callbacks_.erase_after(before);
// Reuse or destroy the callback object.
if (visibly_initialized_callback_ == nullptr) {
visibly_initialized_callback_.reset(callback);
} else {
delete callback;
}
}
void ClassLinker::ForceClassInitialized(Thread* self, Handle<mirror::Class> klass) {
ClassLinker::VisiblyInitializedCallback* cb = MarkClassInitialized(self, klass);
if (cb != nullptr) {
cb->MakeVisible(self);
}
ScopedThreadSuspension sts(self, ThreadState::kSuspended);
MakeInitializedClassesVisiblyInitialized(self, /*wait=*/true);
}
ClassLinker::VisiblyInitializedCallback* ClassLinker::MarkClassInitialized(
Thread* self, Handle<mirror::Class> klass) {
if (kRuntimeISA == InstructionSet::kX86 || kRuntimeISA == InstructionSet::kX86_64) {
// Thanks to the x86 memory model, we do not need any memory fences and
// we can immediately mark the class as visibly initialized.
mirror::Class::SetStatus(klass, ClassStatus::kVisiblyInitialized, self);
FixupStaticTrampolines(self, klass.Get());
return nullptr;
}
if (Runtime::Current()->IsActiveTransaction()) {
// Transactions are single-threaded, so we can mark the class as visibly intialized.
// (Otherwise we'd need to track the callback's entry in the transaction for rollback.)
mirror::Class::SetStatus(klass, ClassStatus::kVisiblyInitialized, self);
FixupStaticTrampolines(self, klass.Get());
return nullptr;
}
mirror::Class::SetStatus(klass, ClassStatus::kInitialized, self);
MutexLock lock(self, visibly_initialized_callback_lock_);
if (visibly_initialized_callback_ == nullptr) {
visibly_initialized_callback_.reset(new VisiblyInitializedCallback(this));
}
DCHECK(!visibly_initialized_callback_->IsFull());
visibly_initialized_callback_->AddClass(self, klass.Get());
if (visibly_initialized_callback_->IsFull()) {
VisiblyInitializedCallback* callback = visibly_initialized_callback_.release();
running_visibly_initialized_callbacks_.push_front(*callback);
return callback;
} else {
return nullptr;
}
}
const void* ClassLinker::RegisterNative(
Thread* self, ArtMethod* method, const void* native_method) {
CHECK(method->IsNative()) << method->PrettyMethod();
CHECK(native_method != nullptr) << method->PrettyMethod();
void* new_native_method = nullptr;
Runtime* runtime = Runtime::Current();
runtime->GetRuntimeCallbacks()->RegisterNativeMethod(method,
native_method,
/*out*/&new_native_method);
if (method->IsCriticalNative()) {
MutexLock lock(self, critical_native_code_with_clinit_check_lock_);
// Remove old registered method if any.
auto it = critical_native_code_with_clinit_check_.find(method);
if (it != critical_native_code_with_clinit_check_.end()) {
critical_native_code_with_clinit_check_.erase(it);
}
// To ensure correct memory visibility, we need the class to be visibly
// initialized before we can set the JNI entrypoint.
if (method->GetDeclaringClass()->IsVisiblyInitialized()) {
method->SetEntryPointFromJni(new_native_method);
} else {
critical_native_code_with_clinit_check_.emplace(method, new_native_method);
}
} else {
method->SetEntryPointFromJni(new_native_method);
}
return new_native_method;
}
void ClassLinker::UnregisterNative(Thread* self, ArtMethod* method) {
CHECK(method->IsNative()) << method->PrettyMethod();
// Restore stub to lookup native pointer via dlsym.
if (method->IsCriticalNative()) {
MutexLock lock(self, critical_native_code_with_clinit_check_lock_);
auto it = critical_native_code_with_clinit_check_.find(method);
if (it != critical_native_code_with_clinit_check_.end()) {
critical_native_code_with_clinit_check_.erase(it);
}
method->SetEntryPointFromJni(GetJniDlsymLookupCriticalStub());
} else {
method->SetEntryPointFromJni(GetJniDlsymLookupStub());
}
}
const void* ClassLinker::GetRegisteredNative(Thread* self, ArtMethod* method) {
if (method->IsCriticalNative()) {
MutexLock lock(self, critical_native_code_with_clinit_check_lock_);
auto it = critical_native_code_with_clinit_check_.find(method);
if (it != critical_native_code_with_clinit_check_.end()) {
return it->second;
}
const void* native_code = method->GetEntryPointFromJni();
return IsJniDlsymLookupCriticalStub(native_code) ? nullptr : native_code;
} else {
const void* native_code = method->GetEntryPointFromJni();
return IsJniDlsymLookupStub(native_code) ? nullptr : native_code;
}
}
void ClassLinker::ThrowEarlierClassFailure(ObjPtr<mirror::Class> c,
bool wrap_in_no_class_def,
bool log) {
// The class failed to initialize on a previous attempt, so we want to throw
// a NoClassDefFoundError (v2 2.17.5). The exception to this rule is if we
// failed in verification, in which case v2 5.4.1 says we need to re-throw
// the previous error.
Runtime* const runtime = Runtime::Current();
if (!runtime->IsAotCompiler()) { // Give info if this occurs at runtime.
std::string extra;
ObjPtr<mirror::Object> verify_error = GetErroneousStateError(c);
if (verify_error != nullptr) {
DCHECK(!verify_error->IsClass());
extra = verify_error->AsThrowable()->Dump();
}
if (log) {
LOG(INFO) << "Rejecting re-init on previously-failed class " << c->PrettyClass()
<< ": " << extra;
}
}
CHECK(c->IsErroneous()) << c->PrettyClass() << " " << c->GetStatus();
Thread* self = Thread::Current();
if (runtime->IsAotCompiler()) {
// At compile time, accurate errors and NCDFE are disabled to speed compilation.
ObjPtr<mirror::Throwable> pre_allocated = runtime->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
} else {
ObjPtr<mirror::Object> erroneous_state_error = GetErroneousStateError(c);
if (erroneous_state_error != nullptr) {
// Rethrow stored error.
HandleEarlierErroneousStateError(self, this, c);
}
// TODO This might be wrong if we hit an OOME while allocating the ClassExt. In that case we
// might have meant to go down the earlier if statement with the original error but it got
// swallowed by the OOM so we end up here.
if (erroneous_state_error == nullptr ||
(wrap_in_no_class_def && !IsVerifyError(erroneous_state_error))) {
// If there isn't a recorded earlier error, or this is a repeat throw from initialization,
// the top-level exception must be a NoClassDefFoundError. The potentially already pending
// exception will be a cause.
self->ThrowNewWrappedException("Ljava/lang/NoClassDefFoundError;",
c->PrettyDescriptor().c_str());
}
}
}
static void VlogClassInitializationFailure(Handle<mirror::Class> klass)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (VLOG_IS_ON(class_linker)) {
std::string temp;
LOG(INFO) << "Failed to initialize class " << klass->GetDescriptor(&temp) << " from "
<< klass->GetLocation() << "\n" << Thread::Current()->GetException()->Dump();
}
}
static void WrapExceptionInInitializer(Handle<mirror::Class> klass)
REQUIRES_SHARED(Locks::mutator_lock_) {
Thread* self = Thread::Current();
JNIEnv* env = self->GetJniEnv();
ScopedLocalRef<jthrowable> cause(env, env->ExceptionOccurred());
CHECK(cause.get() != nullptr);
// Boot classpath classes should not fail initialization. This is a consistency debug check.
// This cannot in general be guaranteed, but in all likelihood leads to breakage down the line.
if (klass->GetClassLoader() == nullptr && !Runtime::Current()->IsAotCompiler()) {
std::string tmp;
// We want to LOG(FATAL) on debug builds since this really shouldn't be happening but we need to
// make sure to only do it if we don't have AsyncExceptions being thrown around since those
// could have caused the error.
bool known_impossible = kIsDebugBuild && !Runtime::Current()->AreAsyncExceptionsThrown();
LOG(known_impossible ? FATAL : WARNING) << klass->GetDescriptor(&tmp)
<< " failed initialization: "
<< self->GetException()->Dump();
}
env->ExceptionClear();
bool is_error = env->IsInstanceOf(cause.get(), WellKnownClasses::java_lang_Error);
env->Throw(cause.get());
// We only wrap non-Error exceptions; an Error can just be used as-is.
if (!is_error) {
self->ThrowNewWrappedException("Ljava/lang/ExceptionInInitializerError;", nullptr);
}
VlogClassInitializationFailure(klass);
}
ClassLinker::ClassLinker(InternTable* intern_table, bool fast_class_not_found_exceptions)
: boot_class_table_(new ClassTable()),
failed_dex_cache_class_lookups_(0),
class_roots_(nullptr),
find_array_class_cache_next_victim_(0),
init_done_(false),
log_new_roots_(false),
intern_table_(intern_table),
fast_class_not_found_exceptions_(fast_class_not_found_exceptions),
jni_dlsym_lookup_trampoline_(nullptr),
jni_dlsym_lookup_critical_trampoline_(nullptr),
quick_resolution_trampoline_(nullptr),
quick_imt_conflict_trampoline_(nullptr),
quick_generic_jni_trampoline_(nullptr),
quick_to_interpreter_bridge_trampoline_(nullptr),
nterp_trampoline_(nullptr),
image_pointer_size_(kRuntimePointerSize),
visibly_initialized_callback_lock_("visibly initialized callback lock"),
visibly_initialized_callback_(nullptr),
critical_native_code_with_clinit_check_lock_("critical native code with clinit check lock"),
critical_native_code_with_clinit_check_(),
cha_(Runtime::Current()->IsAotCompiler() ? nullptr : new ClassHierarchyAnalysis()) {
// For CHA disabled during Aot, see b/34193647.
CHECK(intern_table_ != nullptr);
static_assert(kFindArrayCacheSize == arraysize(find_array_class_cache_),
"Array cache size wrong.");
std::fill_n(find_array_class_cache_, kFindArrayCacheSize, GcRoot<mirror::Class>(nullptr));
}
void ClassLinker::CheckSystemClass(Thread* self, Handle<mirror::Class> c1, const char* descriptor) {
ObjPtr<mirror::Class> c2 = FindSystemClass(self, descriptor);
if (c2 == nullptr) {
LOG(FATAL) << "Could not find class " << descriptor;
UNREACHABLE();
}
if (c1.Get() != c2) {
std::ostringstream os1, os2;
c1->DumpClass(os1, mirror::Class::kDumpClassFullDetail);
c2->DumpClass(os2, mirror::Class::kDumpClassFullDetail);
LOG(FATAL) << "InitWithoutImage: Class mismatch for " << descriptor
<< ". This is most likely the result of a broken build. Make sure that "
<< "libcore and art projects match.\n\n"
<< os1.str() << "\n\n" << os2.str();
UNREACHABLE();
}
}
bool ClassLinker::InitWithoutImage(std::vector<std::unique_ptr<const DexFile>> boot_class_path,
std::string* error_msg) {
VLOG(startup) << "ClassLinker::Init";
Thread* const self = Thread::Current();
Runtime* const runtime = Runtime::Current();
gc::Heap* const heap = runtime->GetHeap();
CHECK(!heap->HasBootImageSpace()) << "Runtime has image. We should use it.";
CHECK(!init_done_);
// Use the pointer size from the runtime since we are probably creating the image.
image_pointer_size_ = InstructionSetPointerSize(runtime->GetInstructionSet());
// java_lang_Class comes first, it's needed for AllocClass
// The GC can't handle an object with a null class since we can't get the size of this object.
heap->IncrementDisableMovingGC(self);
StackHandleScope<64> hs(self); // 64 is picked arbitrarily.
auto class_class_size = mirror::Class::ClassClassSize(image_pointer_size_);
// Allocate the object as non-movable so that there are no cases where Object::IsClass returns
// the incorrect result when comparing to-space vs from-space.
Handle<mirror::Class> java_lang_Class(hs.NewHandle(ObjPtr<mirror::Class>::DownCast(
heap->AllocNonMovableObject(self, nullptr, class_class_size, VoidFunctor()))));
CHECK(java_lang_Class != nullptr);
java_lang_Class->SetClassFlags(mirror::kClassFlagClass);
java_lang_Class->SetClass(java_lang_Class.Get());
if (kUseBakerReadBarrier) {
java_lang_Class->AssertReadBarrierState();
}
java_lang_Class->SetClassSize(class_class_size);
java_lang_Class->SetPrimitiveType(Primitive::kPrimNot);
heap->DecrementDisableMovingGC(self);
// AllocClass(ObjPtr<mirror::Class>) can now be used
// Class[] is used for reflection support.
auto class_array_class_size = mirror::ObjectArray<mirror::Class>::ClassSize(image_pointer_size_);
Handle<mirror::Class> class_array_class(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(), class_array_class_size)));
class_array_class->SetComponentType(java_lang_Class.Get());
// java_lang_Object comes next so that object_array_class can be created.
Handle<mirror::Class> java_lang_Object(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(), mirror::Object::ClassSize(image_pointer_size_))));
CHECK(java_lang_Object != nullptr);
// backfill Object as the super class of Class.
java_lang_Class->SetSuperClass(java_lang_Object.Get());
mirror::Class::SetStatus(java_lang_Object, ClassStatus::kLoaded, self);
java_lang_Object->SetObjectSize(sizeof(mirror::Object));
// Allocate in non-movable so that it's possible to check if a JNI weak global ref has been
// cleared without triggering the read barrier and unintentionally mark the sentinel alive.
runtime->SetSentinel(heap->AllocNonMovableObject(self,
java_lang_Object.Get(),
java_lang_Object->GetObjectSize(),
VoidFunctor()));
// Initialize the SubtypeCheck bitstring for java.lang.Object and java.lang.Class.
if (kBitstringSubtypeCheckEnabled) {
// It might seem the lock here is unnecessary, however all the SubtypeCheck
// functions are annotated to require locks all the way down.
//
// We take the lock here to avoid using NO_THREAD_SAFETY_ANALYSIS.
MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
SubtypeCheck<ObjPtr<mirror::Class>>::EnsureInitialized(java_lang_Object.Get());
SubtypeCheck<ObjPtr<mirror::Class>>::EnsureInitialized(java_lang_Class.Get());
}
// Object[] next to hold class roots.
Handle<mirror::Class> object_array_class(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(),
mirror::ObjectArray<mirror::Object>::ClassSize(image_pointer_size_))));
object_array_class->SetComponentType(java_lang_Object.Get());
// Setup java.lang.String.
//
// We make this class non-movable for the unlikely case where it were to be
// moved by a sticky-bit (minor) collection when using the Generational
// Concurrent Copying (CC) collector, potentially creating a stale reference
// in the `klass_` field of one of its instances allocated in the Large-Object
// Space (LOS) -- see the comment about the dirty card scanning logic in
// art::gc::collector::ConcurrentCopying::MarkingPhase.
Handle<mirror::Class> java_lang_String(hs.NewHandle(
AllocClass</* kMovable= */ false>(
self, java_lang_Class.Get(), mirror::String::ClassSize(image_pointer_size_))));
java_lang_String->SetStringClass();
mirror::Class::SetStatus(java_lang_String, ClassStatus::kResolved, self);
// Setup java.lang.ref.Reference.
Handle<mirror::Class> java_lang_ref_Reference(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(), mirror::Reference::ClassSize(image_pointer_size_))));
java_lang_ref_Reference->SetObjectSize(mirror::Reference::InstanceSize());
mirror::Class::SetStatus(java_lang_ref_Reference, ClassStatus::kResolved, self);
// Create storage for root classes, save away our work so far (requires descriptors).
class_roots_ = GcRoot<mirror::ObjectArray<mirror::Class>>(
mirror::ObjectArray<mirror::Class>::Alloc(self,
object_array_class.Get(),
static_cast<int32_t>(ClassRoot::kMax)));
CHECK(!class_roots_.IsNull());
SetClassRoot(ClassRoot::kJavaLangClass, java_lang_Class.Get());
SetClassRoot(ClassRoot::kJavaLangObject, java_lang_Object.Get());
SetClassRoot(ClassRoot::kClassArrayClass, class_array_class.Get());
SetClassRoot(ClassRoot::kObjectArrayClass, object_array_class.Get());
SetClassRoot(ClassRoot::kJavaLangString, java_lang_String.Get());
SetClassRoot(ClassRoot::kJavaLangRefReference, java_lang_ref_Reference.Get());
// Fill in the empty iftable. Needs to be done after the kObjectArrayClass root is set.
java_lang_Object->SetIfTable(AllocIfTable(self, 0));
// Create array interface entries to populate once we can load system classes.
object_array_class->SetIfTable(AllocIfTable(self, 2));
DCHECK_EQ(GetArrayIfTable(), object_array_class->GetIfTable());
// Setup the primitive type classes.
CreatePrimitiveClass(self, Primitive::kPrimBoolean, ClassRoot::kPrimitiveBoolean);
CreatePrimitiveClass(self, Primitive::kPrimByte, ClassRoot::kPrimitiveByte);
CreatePrimitiveClass(self, Primitive::kPrimChar, ClassRoot::kPrimitiveChar);
CreatePrimitiveClass(self, Primitive::kPrimShort, ClassRoot::kPrimitiveShort);
CreatePrimitiveClass(self, Primitive::kPrimInt, ClassRoot::kPrimitiveInt);
CreatePrimitiveClass(self, Primitive::kPrimLong, ClassRoot::kPrimitiveLong);
CreatePrimitiveClass(self, Primitive::kPrimFloat, ClassRoot::kPrimitiveFloat);
CreatePrimitiveClass(self, Primitive::kPrimDouble, ClassRoot::kPrimitiveDouble);
CreatePrimitiveClass(self, Primitive::kPrimVoid, ClassRoot::kPrimitiveVoid);
// Allocate the primitive array classes. We need only the native pointer
// array at this point (int[] or long[], depending on architecture) but
// we shall perform the same setup steps for all primitive array classes.
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveBoolean, ClassRoot::kBooleanArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveByte, ClassRoot::kByteArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveChar, ClassRoot::kCharArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveShort, ClassRoot::kShortArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveInt, ClassRoot::kIntArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveLong, ClassRoot::kLongArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveFloat, ClassRoot::kFloatArrayClass);
AllocPrimitiveArrayClass(self, ClassRoot::kPrimitiveDouble, ClassRoot::kDoubleArrayClass);
// now that these are registered, we can use AllocClass() and AllocObjectArray
// Set up DexCache. This cannot be done later since AppendToBootClassPath calls AllocDexCache.
Handle<mirror::Class> java_lang_DexCache(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(), mirror::DexCache::ClassSize(image_pointer_size_))));
SetClassRoot(ClassRoot::kJavaLangDexCache, java_lang_DexCache.Get());
java_lang_DexCache->SetDexCacheClass();
java_lang_DexCache->SetObjectSize(mirror::DexCache::InstanceSize());
mirror::Class::SetStatus(java_lang_DexCache, ClassStatus::kResolved, self);
// Setup dalvik.system.ClassExt
Handle<mirror::Class> dalvik_system_ClassExt(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(), mirror::ClassExt::ClassSize(image_pointer_size_))));
SetClassRoot(ClassRoot::kDalvikSystemClassExt, dalvik_system_ClassExt.Get());
mirror::Class::SetStatus(dalvik_system_ClassExt, ClassStatus::kResolved, self);
// Set up array classes for string, field, method
Handle<mirror::Class> object_array_string(hs.NewHandle(
AllocClass(self, java_lang_Class.Get(),
mirror::ObjectArray<mirror::String>::ClassSize(image_pointer_size_))));
object_array_string->SetComponentType(java_lang_String.Get());
SetClassRoot(ClassRoot::kJavaLangStringArrayClass, object_array_string.Get());
LinearAlloc* linear_alloc = runtime->GetLinearAlloc();
// Create runtime resolution and imt conflict methods.
runtime->SetResolutionMethod(runtime->CreateResolutionMethod());
runtime->SetImtConflictMethod(runtime->CreateImtConflictMethod(linear_alloc));
runtime->SetImtUnimplementedMethod(runtime->CreateImtConflictMethod(linear_alloc));
// Setup boot_class_path_ and register class_path now that we can use AllocObjectArray to create
// DexCache instances. Needs to be after String, Field, Method arrays since AllocDexCache uses
// these roots.
if (boot_class_path.empty()) {
*error_msg = "Boot classpath is empty.";
return false;
}
for (auto& dex_file : boot_class_path) {
if (dex_file == nullptr) {
*error_msg = "Null dex file.";
return false;
}
AppendToBootClassPath(self, dex_file.get());
boot_dex_files_.push_back(std::move(dex_file));
}
// now we can use FindSystemClass
// Set up GenericJNI entrypoint. That is mainly a hack for common_compiler_test.h so that
// we do not need friend classes or a publicly exposed setter.
quick_generic_jni_trampoline_ = GetQuickGenericJniStub();
if (!runtime->IsAotCompiler()) {
// We need to set up the generic trampolines since we don't have an image.
jni_dlsym_lookup_trampoline_ = GetJniDlsymLookupStub();
jni_dlsym_lookup_critical_trampoline_ = GetJniDlsymLookupCriticalStub();
quick_resolution_trampoline_ = GetQuickResolutionStub();
quick_imt_conflict_trampoline_ = GetQuickImtConflictStub();
quick_generic_jni_trampoline_ = GetQuickGenericJniStub();
quick_to_interpreter_bridge_trampoline_ = GetQuickToInterpreterBridge();
nterp_trampoline_ = interpreter::GetNterpEntryPoint();
}
// Object, String, ClassExt and DexCache need to be rerun through FindSystemClass to finish init
mirror::Class::SetStatus(java_lang_Object, ClassStatus::kNotReady, self);
CheckSystemClass(self, java_lang_Object, "Ljava/lang/Object;");
CHECK_EQ(java_lang_Object->GetObjectSize(), mirror::Object::InstanceSize());
mirror::Class::SetStatus(java_lang_String, ClassStatus::kNotReady, self);
CheckSystemClass(self, java_lang_String, "Ljava/lang/String;");
mirror::Class::SetStatus(java_lang_DexCache, ClassStatus::kNotReady, self);
CheckSystemClass(self, java_lang_DexCache, "Ljava/lang/DexCache;");
CHECK_EQ(java_lang_DexCache->GetObjectSize(), mirror::DexCache::InstanceSize());
mirror::Class::SetStatus(dalvik_system_ClassExt, ClassStatus::kNotReady, self);
CheckSystemClass(self, dalvik_system_ClassExt, "Ldalvik/system/ClassExt;");
CHECK_EQ(dalvik_system_ClassExt->GetObjectSize(), mirror::ClassExt::InstanceSize());
// Run Class through FindSystemClass. This initializes the dex_cache_ fields and register it
// in class_table_.
CheckSystemClass(self, java_lang_Class, "Ljava/lang/Class;");
// Setup core array classes, i.e. Object[], String[] and Class[] and primitive
// arrays - can't be done until Object has a vtable and component classes are loaded.
FinishCoreArrayClassSetup(ClassRoot::kObjectArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kClassArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kJavaLangStringArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kBooleanArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kByteArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kCharArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kShortArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kIntArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kLongArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kFloatArrayClass);
FinishCoreArrayClassSetup(ClassRoot::kDoubleArrayClass);
// Setup the single, global copy of "iftable".
auto java_lang_Cloneable = hs.NewHandle(FindSystemClass(self, "Ljava/lang/Cloneable;"));
CHECK(java_lang_Cloneable != nullptr);
auto java_io_Serializable = hs.NewHandle(FindSystemClass(self, "Ljava/io/Serializable;"));
CHECK(java_io_Serializable != nullptr);
// We assume that Cloneable/Serializable don't have superinterfaces -- normally we'd have to
// crawl up and explicitly list all of the supers as well.
object_array_class->GetIfTable()->SetInterface(0, java_lang_Cloneable.Get());
object_array_class->GetIfTable()->SetInterface(1, java_io_Serializable.Get());
// Check Class[] and Object[]'s interfaces.
CHECK_EQ(java_lang_Cloneable.Get(), class_array_class->GetDirectInterface(0));
CHECK_EQ(java_io_Serializable.Get(), class_array_class->GetDirectInterface(1));
CHECK_EQ(java_lang_Cloneable.Get(), object_array_class->GetDirectInterface(0));
CHECK_EQ(java_io_Serializable.Get(), object_array_class->GetDirectInterface(1));
CHECK_EQ(object_array_string.Get(),
FindSystemClass(self, GetClassRootDescriptor(ClassRoot::kJavaLangStringArrayClass)));
// End of special init trickery, all subsequent classes may be loaded via FindSystemClass.
// Create java.lang.reflect.Proxy root.
SetClassRoot(ClassRoot::kJavaLangReflectProxy,
FindSystemClass(self, "Ljava/lang/reflect/Proxy;"));
// Create java.lang.reflect.Field.class root.
ObjPtr<mirror::Class> class_root = FindSystemClass(self, "Ljava/lang/reflect/Field;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangReflectField, class_root);
// Create java.lang.reflect.Field array root.
class_root = FindSystemClass(self, "[Ljava/lang/reflect/Field;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangReflectFieldArrayClass, class_root);
// Create java.lang.reflect.Constructor.class root and array root.
class_root = FindSystemClass(self, "Ljava/lang/reflect/Constructor;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangReflectConstructor, class_root);
class_root = FindSystemClass(self, "[Ljava/lang/reflect/Constructor;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangReflectConstructorArrayClass, class_root);
// Create java.lang.reflect.Method.class root and array root.
class_root = FindSystemClass(self, "Ljava/lang/reflect/Method;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangReflectMethod, class_root);
class_root = FindSystemClass(self, "[Ljava/lang/reflect/Method;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangReflectMethodArrayClass, class_root);
// Create java.lang.invoke.CallSite.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/CallSite;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeCallSite, class_root);
// Create java.lang.invoke.MethodType.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/MethodType;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeMethodType, class_root);
// Create java.lang.invoke.MethodHandleImpl.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/MethodHandleImpl;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeMethodHandleImpl, class_root);
SetClassRoot(ClassRoot::kJavaLangInvokeMethodHandle, class_root->GetSuperClass());
// Create java.lang.invoke.MethodHandles.Lookup.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/MethodHandles$Lookup;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeMethodHandlesLookup, class_root);
// Create java.lang.invoke.VarHandle.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/VarHandle;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeVarHandle, class_root);
// Create java.lang.invoke.FieldVarHandle.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/FieldVarHandle;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeFieldVarHandle, class_root);
// Create java.lang.invoke.StaticFieldVarHandle.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/StaticFieldVarHandle;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeStaticFieldVarHandle, class_root);
// Create java.lang.invoke.ArrayElementVarHandle.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/ArrayElementVarHandle;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeArrayElementVarHandle, class_root);
// Create java.lang.invoke.ByteArrayViewVarHandle.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/ByteArrayViewVarHandle;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeByteArrayViewVarHandle, class_root);
// Create java.lang.invoke.ByteBufferViewVarHandle.class root
class_root = FindSystemClass(self, "Ljava/lang/invoke/ByteBufferViewVarHandle;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kJavaLangInvokeByteBufferViewVarHandle, class_root);
class_root = FindSystemClass(self, "Ldalvik/system/EmulatedStackFrame;");
CHECK(class_root != nullptr);
SetClassRoot(ClassRoot::kDalvikSystemEmulatedStackFrame, class_root);
// java.lang.ref classes need to be specially flagged, but otherwise are normal classes
// finish initializing Reference class
mirror::Class::SetStatus(java_lang_ref_Reference, ClassStatus::kNotReady, self);
CheckSystemClass(self, java_lang_ref_Reference, "Ljava/lang/ref/Reference;");
CHECK_EQ(java_lang_ref_Reference->GetObjectSize(), mirror::Reference::InstanceSize());
CHECK_EQ(java_lang_ref_Reference->GetClassSize(),
mirror::Reference::ClassSize(image_pointer_size_));
class_root = FindSystemClass(self, "Ljava/lang/ref/FinalizerReference;");
CHECK_EQ(class_root->GetClassFlags(), mirror::kClassFlagNormal);
class_root->SetClassFlags(class_root->GetClassFlags() | mirror::kClassFlagFinalizerReference);
class_root = FindSystemClass(self, "Ljava/lang/ref/PhantomReference;");
CHECK_EQ(class_root->GetClassFlags(), mirror::kClassFlagNormal);
class_root->SetClassFlags(class_root->GetClassFlags() | mirror::kClassFlagPhantomReference);
class_root = FindSystemClass(self, "Ljava/lang/ref/SoftReference;");
CHECK_EQ(class_root->GetClassFlags(), mirror::kClassFlagNormal);
class_root->SetClassFlags(class_root->GetClassFlags() | mirror::kClassFlagSoftReference);
class_root = FindSystemClass(self, "Ljava/lang/ref/WeakReference;");
CHECK_EQ(class_root->GetClassFlags(), mirror::kClassFlagNormal);
class_root->SetClassFlags(class_root->GetClassFlags() | mirror::kClassFlagWeakReference);
// Setup the ClassLoader, verifying the object_size_.
class_root = FindSystemClass(self, "Ljava/lang/ClassLoader;");
class_root->SetClassLoaderClass();
CHECK_EQ(class_root->GetObjectSize(), mirror::ClassLoader::InstanceSize());
SetClassRoot(ClassRoot::kJavaLangClassLoader, class_root);
// Set up java.lang.Throwable, java.lang.ClassNotFoundException, and
// java.lang.StackTraceElement as a convenience.
SetClassRoot(ClassRoot::kJavaLangThrowable, FindSystemClass(self, "Ljava/lang/Throwable;"));
SetClassRoot(ClassRoot::kJavaLangClassNotFoundException,
FindSystemClass(self, "Ljava/lang/ClassNotFoundException;"));
SetClassRoot(ClassRoot::kJavaLangStackTraceElement,
FindSystemClass(self, "Ljava/lang/StackTraceElement;"));
SetClassRoot(ClassRoot::kJavaLangStackTraceElementArrayClass,
FindSystemClass(self, "[Ljava/lang/StackTraceElement;"));
SetClassRoot(ClassRoot::kJavaLangClassLoaderArrayClass,
FindSystemClass(self, "[Ljava/lang/ClassLoader;"));
// Create conflict tables that depend on the class linker.
runtime->FixupConflictTables();
FinishInit(self);
VLOG(startup) << "ClassLinker::InitFromCompiler exiting";
return true;
}
static void CreateStringInitBindings(Thread* self, ClassLinker* class_linker)
REQUIRES_SHARED(Locks::mutator_lock_) {
// Find String.<init> -> StringFactory bindings.
ObjPtr<mirror::Class> string_factory_class =
class_linker->FindSystemClass(self, "Ljava/lang/StringFactory;");
CHECK(string_factory_class != nullptr);
ObjPtr<mirror::Class> string_class = GetClassRoot<mirror::String>(class_linker);
WellKnownClasses::InitStringInit(string_class, string_factory_class);
// Update the primordial thread.
self->InitStringEntryPoints();
}
void ClassLinker::FinishInit(Thread* self) {
VLOG(startup) << "ClassLinker::FinishInit entering";
CreateStringInitBindings(self, this);
// Let the heap know some key offsets into java.lang.ref instances
// Note: we hard code the field indexes here rather than using FindInstanceField
// as the types of the field can't be resolved prior to the runtime being
// fully initialized
StackHandleScope<3> hs(self);
Handle<mirror::Class> java_lang_ref_Reference =
hs.NewHandle(GetClassRoot<mirror::Reference>(this));
Handle<mirror::Class> java_lang_ref_FinalizerReference =
hs.NewHandle(FindSystemClass(self, "Ljava/lang/ref/FinalizerReference;"));
ArtField* pendingNext = java_lang_ref_Reference->GetInstanceField(0);
CHECK_STREQ(pendingNext->GetName(), "pendingNext");
CHECK_STREQ(pendingNext->GetTypeDescriptor(), "Ljava/lang/ref/Reference;");
ArtField* queue = java_lang_ref_Reference->GetInstanceField(1);
CHECK_STREQ(queue->GetName(), "queue");
CHECK_STREQ(queue->GetTypeDescriptor(), "Ljava/lang/ref/ReferenceQueue;");
ArtField* queueNext = java_lang_ref_Reference->GetInstanceField(2);
CHECK_STREQ(queueNext->GetName(), "queueNext");
CHECK_STREQ(queueNext->GetTypeDescriptor(), "Ljava/lang/ref/Reference;");
ArtField* referent = java_lang_ref_Reference->GetInstanceField(3);
CHECK_STREQ(referent->GetName(), "referent");
CHECK_STREQ(referent->GetTypeDescriptor(), "Ljava/lang/Object;");
ArtField* zombie = java_lang_ref_FinalizerReference->GetInstanceField(2);
CHECK_STREQ(zombie->GetName(), "zombie");
CHECK_STREQ(zombie->GetTypeDescriptor(), "Ljava/lang/Object;");
// ensure all class_roots_ are initialized
for (size_t i = 0; i < static_cast<size_t>(ClassRoot::kMax); i++) {
ClassRoot class_root = static_cast<ClassRoot>(i);
ObjPtr<mirror::Class> klass = GetClassRoot(class_root);
CHECK(klass != nullptr);
DCHECK(klass->IsArrayClass() || klass->IsPrimitive() || klass->GetDexCache() != nullptr);
// note SetClassRoot does additional validation.
// if possible add new checks there to catch errors early
}
CHECK(GetArrayIfTable() != nullptr);
// disable the slow paths in FindClass and CreatePrimitiveClass now
// that Object, Class, and Object[] are setup
init_done_ = true;
// Under sanitization, the small carve-out to handle stack overflow might not be enough to
// initialize the StackOverflowError class (as it might require running the verifier). Instead,
// ensure that the class will be initialized.
if (kMemoryToolIsAvailable && !Runtime::Current()->IsAotCompiler()) {
verifier::ClassVerifier::Init(this); // Need to prepare the verifier.
ObjPtr<mirror::Class> soe_klass = FindSystemClass(self, "Ljava/lang/StackOverflowError;");
if (soe_klass == nullptr || !EnsureInitialized(self, hs.NewHandle(soe_klass), true, true)) {
// Strange, but don't crash.
LOG(WARNING) << "Could not prepare StackOverflowError.";
self->ClearException();
}
}
VLOG(startup) << "ClassLinker::FinishInit exiting";
}
void ClassLinker::RunRootClinits(Thread* self) {
for (size_t i = 0; i < static_cast<size_t>(ClassRoot::kMax); ++i) {
ObjPtr<mirror::Class> c = GetClassRoot(ClassRoot(i), this);
if (!c->IsArrayClass() && !c->IsPrimitive()) {
StackHandleScope<1> hs(self);
Handle<mirror::Class> h_class(hs.NewHandle(c));
if (!EnsureInitialized(self, h_class, true, true)) {
LOG(FATAL) << "Exception when initializing " << h_class->PrettyClass()
<< ": " << self->GetException()->Dump();
}
} else {
DCHECK(c->IsInitialized());
}
}
}
static void InitializeObjectVirtualMethodHashes(ObjPtr<mirror::Class> java_lang_Object,
PointerSize pointer_size,
/*out*/ ArrayRef<uint32_t> virtual_method_hashes)
REQUIRES_SHARED(Locks::mutator_lock_) {
ArraySlice<ArtMethod> virtual_methods = java_lang_Object->GetVirtualMethods(pointer_size);
DCHECK_EQ(virtual_method_hashes.size(), virtual_methods.size());
for (size_t i = 0; i != virtual_method_hashes.size(); ++i) {
std::string_view name = virtual_methods[i].GetNameView();
virtual_method_hashes[i] = ComputeModifiedUtf8Hash(name);
}
}
struct TrampolineCheckData {
const void* quick_resolution_trampoline;
const void* quick_imt_conflict_trampoline;
const void* quick_generic_jni_trampoline;
const void* quick_to_interpreter_bridge_trampoline;
const void* nterp_trampoline;
PointerSize pointer_size;
ArtMethod* m;
bool error;
};
bool ClassLinker::InitFromBootImage(std::string* error_msg) {
VLOG(startup) << __FUNCTION__ << " entering";
CHECK(!init_done_);
Runtime* const runtime = Runtime::Current();
Thread* const self = Thread::Current();
gc::Heap* const heap = runtime->GetHeap();
std::vector<gc::space::ImageSpace*> spaces = heap->GetBootImageSpaces();
CHECK(!spaces.empty());
const ImageHeader& image_header = spaces[0]->GetImageHeader();
uint32_t pointer_size_unchecked = image_header.GetPointerSizeUnchecked();
if (!ValidPointerSize(pointer_size_unchecked)) {
*error_msg = StringPrintf("Invalid image pointer size: %u", pointer_size_unchecked);
return false;
}
image_pointer_size_ = image_header.GetPointerSize();
if (!runtime->IsAotCompiler()) {
// Only the Aot compiler supports having an image with a different pointer size than the
// runtime. This happens on the host for compiling 32 bit tests since we use a 64 bit libart
// compiler. We may also use 32 bit dex2oat on a system with 64 bit apps.
if (image_pointer_size_ != kRuntimePointerSize) {
*error_msg = StringPrintf("Runtime must use current image pointer size: %zu vs %zu",
static_cast<size_t>(image_pointer_size_),
sizeof(void*));
return false;
}
}
DCHECK(!runtime->HasResolutionMethod());
runtime->SetResolutionMethod(image_header.GetImageMethod(ImageHeader::kResolutionMethod));
runtime->SetImtConflictMethod(image_header.GetImageMethod(ImageHeader::kImtConflictMethod));
runtime->SetImtUnimplementedMethod(
image_header.GetImageMethod(ImageHeader::kImtUnimplementedMethod));
runtime->SetCalleeSaveMethod(
image_header.GetImageMethod(ImageHeader::kSaveAllCalleeSavesMethod),
CalleeSaveType::kSaveAllCalleeSaves);
runtime->SetCalleeSaveMethod(
image_header.GetImageMethod(ImageHeader::kSaveRefsOnlyMethod),
CalleeSaveType::kSaveRefsOnly);
runtime->SetCalleeSaveMethod(
image_header.GetImageMethod(ImageHeader::kSaveRefsAndArgsMethod),
CalleeSaveType::kSaveRefsAndArgs);
runtime->SetCalleeSaveMethod(
image_header.GetImageMethod(ImageHeader::kSaveEverythingMethod),
CalleeSaveType::kSaveEverything);
runtime->SetCalleeSaveMethod(
image_header.GetImageMethod(ImageHeader::kSaveEverythingMethodForClinit),
CalleeSaveType::kSaveEverythingForClinit);
runtime->SetCalleeSaveMethod(
image_header.GetImageMethod(ImageHeader::kSaveEverythingMethodForSuspendCheck),
CalleeSaveType::kSaveEverythingForSuspendCheck);
std::vector<const OatFile*> oat_files =
runtime->GetOatFileManager().RegisterImageOatFiles(spaces);
DCHECK(!oat_files.empty());
const OatHeader& default_oat_header = oat_files[0]->GetOatHeader();
jni_dlsym_lookup_trampoline_ = default_oat_header.GetJniDlsymLookupTrampoline();
jni_dlsym_lookup_critical_trampoline_ = default_oat_header.GetJniDlsymLookupCriticalTrampoline();
quick_resolution_trampoline_ = default_oat_header.GetQuickResolutionTrampoline();
quick_imt_conflict_trampoline_ = default_oat_header.GetQuickImtConflictTrampoline();
quick_generic_jni_trampoline_ = default_oat_header.GetQuickGenericJniTrampoline();
quick_to_interpreter_bridge_trampoline_ = default_oat_header.GetQuickToInterpreterBridge();
nterp_trampoline_ = default_oat_header.GetNterpTrampoline();
if (kIsDebugBuild) {
// Check that the other images use the same trampoline.
for (size_t i = 1; i < oat_files.size(); ++i) {
const OatHeader& ith_oat_header = oat_files[i]->GetOatHeader();
const void* ith_jni_dlsym_lookup_trampoline_ =
ith_oat_header.GetJniDlsymLookupTrampoline();
const void* ith_jni_dlsym_lookup_critical_trampoline_ =
ith_oat_header.GetJniDlsymLookupCriticalTrampoline();
const void* ith_quick_resolution_trampoline =
ith_oat_header.GetQuickResolutionTrampoline();
const void* ith_quick_imt_conflict_trampoline =
ith_oat_header.GetQuickImtConflictTrampoline();
const void* ith_quick_generic_jni_trampoline =
ith_oat_header.GetQuickGenericJniTrampoline();
const void* ith_quick_to_interpreter_bridge_trampoline =
ith_oat_header.GetQuickToInterpreterBridge();
const void* ith_nterp_trampoline =
ith_oat_header.GetNterpTrampoline();
if (ith_jni_dlsym_lookup_trampoline_ != jni_dlsym_lookup_trampoline_ ||
ith_jni_dlsym_lookup_critical_trampoline_ != jni_dlsym_lookup_critical_trampoline_ ||
ith_quick_resolution_trampoline != quick_resolution_trampoline_ ||
ith_quick_imt_conflict_trampoline != quick_imt_conflict_trampoline_ ||
ith_quick_generic_jni_trampoline != quick_generic_jni_trampoline_ ||
ith_quick_to_interpreter_bridge_trampoline != quick_to_interpreter_bridge_trampoline_ ||
ith_nterp_trampoline != nterp_trampoline_) {
// Make sure that all methods in this image do not contain those trampolines as
// entrypoints. Otherwise the class-linker won't be able to work with a single set.
TrampolineCheckData data;
data.error = false;
data.pointer_size = GetImagePointerSize();
data.quick_resolution_trampoline = ith_quick_resolution_trampoline;
data.quick_imt_conflict_trampoline = ith_quick_imt_conflict_trampoline;
data.quick_generic_jni_trampoline = ith_quick_generic_jni_trampoline;
data.quick_to_interpreter_bridge_trampoline = ith_quick_to_interpreter_bridge_trampoline;
data.nterp_trampoline = ith_nterp_trampoline;
ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_);
auto visitor = [&](mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_) {
if (obj->IsClass()) {
ObjPtr<mirror::Class> klass = obj->AsClass();
for (ArtMethod& m : klass->GetMethods(data.pointer_size)) {
const void* entrypoint =
m.GetEntryPointFromQuickCompiledCodePtrSize(data.pointer_size);
if (entrypoint == data.quick_resolution_trampoline ||
entrypoint == data.quick_imt_conflict_trampoline ||
entrypoint == data.quick_generic_jni_trampoline ||
entrypoint == data.quick_to_interpreter_bridge_trampoline) {
data.m = &m;
data.error = true;
return;
}
}
}
};
spaces[i]->GetLiveBitmap()->Walk(visitor);
if (data.error) {
ArtMethod* m = data.m;
LOG(ERROR) << "Found a broken ArtMethod: " << ArtMethod::PrettyMethod(m);
*error_msg = "Found an ArtMethod with a bad entrypoint";
return false;
}
}
}
}
class_roots_ = GcRoot<mirror::ObjectArray<mirror::Class>>(
ObjPtr<mirror::ObjectArray<mirror::Class>>::DownCast(
image_header.GetImageRoot(ImageHeader::kClassRoots)));
DCHECK_EQ(GetClassRoot<mirror::Class>(this)->GetClassFlags(), mirror::kClassFlagClass);
DCHECK_EQ(GetClassRoot<mirror::Object>(this)->GetObjectSize(), sizeof(mirror::Object));
ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects =
ObjPtr<mirror::ObjectArray<mirror::Object>>::DownCast(
image_header.GetImageRoot(ImageHeader::kBootImageLiveObjects));
runtime->SetSentinel(boot_image_live_objects->Get(ImageHeader::kClearedJniWeakSentinel));
DCHECK(runtime->GetSentinel().Read()->GetClass() == GetClassRoot<mirror::Object>(this));
for (size_t i = 0u, size = spaces.size(); i != size; ++i) {
// Boot class loader, use a null handle.
std::vector<std::unique_ptr<const DexFile>> dex_files;
if (!AddImageSpace(spaces[i],
ScopedNullHandle<mirror::ClassLoader>(),
/*out*/&dex_files,
error_msg)) {
return false;
}
// Append opened dex files at the end.
boot_dex_files_.insert(boot_dex_files_.end(),
std::make_move_iterator(dex_files.begin()),
std::make_move_iterator(dex_files.end()));
}
for (const std::unique_ptr<const DexFile>& dex_file : boot_dex_files_) {
OatDexFile::MadviseDexFileAtLoad(*dex_file);
}
InitializeObjectVirtualMethodHashes(GetClassRoot<mirror::Object>(this),
image_pointer_size_,
ArrayRef<uint32_t>(object_virtual_method_hashes_));
FinishInit(self);
VLOG(startup) << __FUNCTION__ << " exiting";
return true;
}
void ClassLinker::AddExtraBootDexFiles(
Thread* self,
std::vector<std::unique_ptr<const DexFile>>&& additional_dex_files) {
for (std::unique_ptr<const DexFile>& dex_file : additional_dex_files) {
AppendToBootClassPath(self, dex_file.get());
if (kIsDebugBuild) {
for (const auto& boot_dex_file : boot_dex_files_) {
DCHECK_NE(boot_dex_file->GetLocation(), dex_file->GetLocation());
}
}
boot_dex_files_.push_back(std::move(dex_file));
}
}
bool ClassLinker::IsBootClassLoader(ScopedObjectAccessAlreadyRunnable& soa,
ObjPtr<mirror::ClassLoader> class_loader) {
return class_loader == nullptr ||
soa.Decode<mirror::Class>(WellKnownClasses::java_lang_BootClassLoader) ==
class_loader->GetClass();
}
class CHAOnDeleteUpdateClassVisitor {
public:
explicit CHAOnDeleteUpdateClassVisitor(LinearAlloc* alloc)
: allocator_(alloc), cha_(Runtime::Current()->GetClassLinker()->GetClassHierarchyAnalysis()),
pointer_size_(Runtime::Current()->GetClassLinker()->GetImagePointerSize()),
self_(Thread::Current()) {}
bool operator()(ObjPtr<mirror::Class> klass) REQUIRES_SHARED(Locks::mutator_lock_) {
// This class is going to be unloaded. Tell CHA about it.
cha_->ResetSingleImplementationInHierarchy(klass, allocator_, pointer_size_);
return true;
}
private:
const LinearAlloc* allocator_;
const ClassHierarchyAnalysis* cha_;
const PointerSize pointer_size_;
const Thread* self_;
};
/*
* A class used to ensure that all references to strings interned in an AppImage have been
* properly recorded in the interned references list, and is only ever run in debug mode.
*/
class CountInternedStringReferencesVisitor {
public:
CountInternedStringReferencesVisitor(const gc::space::ImageSpace& space,
const InternTable::UnorderedSet& image_interns)
: space_(space),
image_interns_(image_interns),
count_(0u) {}
void TestObject(ObjPtr<mirror::Object> referred_obj) const
REQUIRES_SHARED(Locks::mutator_lock_) {
if (referred_obj != nullptr &&
space_.HasAddress(referred_obj.Ptr()) &&
referred_obj->IsString()) {
ObjPtr<mirror::String> referred_str = referred_obj->AsString();
auto it = image_interns_.find(GcRoot<mirror::String>(referred_str));
if (it != image_interns_.end() && it->Read() == referred_str) {
++count_;
}
}
}
void VisitRootIfNonNull(
mirror::CompressedReference<mirror::Object>* root) const
REQUIRES_SHARED(Locks::mutator_lock_) {
if (!root->IsNull()) {
VisitRoot(root);
}
}
void VisitRoot(mirror::CompressedReference<mirror::Object>* root) const
REQUIRES_SHARED(Locks::mutator_lock_) {
TestObject(root->AsMirrorPtr());
}
// Visit Class Fields
void operator()(ObjPtr<mirror::Object> obj,
MemberOffset offset,
bool is_static ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// References within image or across images don't need a read barrier.
ObjPtr<mirror::Object> referred_obj =
obj->GetFieldObject<mirror::Object, kVerifyNone, kWithoutReadBarrier>(offset);
TestObject(referred_obj);
}
void operator()(ObjPtr<mirror::Class> klass ATTRIBUTE_UNUSED,
ObjPtr<mirror::Reference> ref) const
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(Locks::heap_bitmap_lock_) {
operator()(ref, mirror::Reference::ReferentOffset(), /*is_static=*/ false);
}
size_t GetCount() const {
return count_;
}
private:
const gc::space::ImageSpace& space_;
const InternTable::UnorderedSet& image_interns_;
mutable size_t count_; // Modified from the `const` callbacks.
};
/*
* This function counts references to strings interned in the AppImage.
* This is used in debug build to check against the number of the recorded references.
*/
size_t CountInternedStringReferences(gc::space::ImageSpace& space,
const InternTable::UnorderedSet& image_interns)
REQUIRES_SHARED(Locks::mutator_lock_) {
const gc::accounting::ContinuousSpaceBitmap* bitmap = space.GetMarkBitmap();
const ImageHeader& image_header = space.GetImageHeader();
const uint8_t* target_base = space.GetMemMap()->Begin();
const ImageSection& objects_section = image_header.GetObjectsSection();
auto objects_begin = reinterpret_cast<uintptr_t>(target_base + objects_section.Offset());
auto objects_end = reinterpret_cast<uintptr_t>(target_base + objects_section.End());
CountInternedStringReferencesVisitor visitor(space, image_interns);
bitmap->VisitMarkedRange(objects_begin,
objects_end,
[&space, &visitor](mirror::Object* obj)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (space.HasAddress(obj)) {
if (obj->IsDexCache()) {
obj->VisitReferences</* kVisitNativeRoots= */ true,
kVerifyNone,
kWithoutReadBarrier>(visitor, visitor);
} else {
// Don't visit native roots for non-dex-cache as they can't contain
// native references to strings. This is verified during compilation
// by ImageWriter::VerifyNativeGCRootInvariants.
obj->VisitReferences</* kVisitNativeRoots= */ false,
kVerifyNone,
kWithoutReadBarrier>(visitor, visitor);
}
}
});
return visitor.GetCount();
}
template <typename Visitor>
static void VisitInternedStringReferences(
gc::space::ImageSpace* space,
const Visitor& visitor) REQUIRES_SHARED(Locks::mutator_lock_) {
const uint8_t* target_base = space->Begin();
const ImageSection& sro_section =
space->GetImageHeader().GetImageStringReferenceOffsetsSection();
const size_t num_string_offsets = sro_section.Size() / sizeof(AppImageReferenceOffsetInfo);
VLOG(image)
<< "ClassLinker:AppImage:InternStrings:imageStringReferenceOffsetCount = "
<< num_string_offsets;
const auto* sro_base =
reinterpret_cast<const AppImageReferenceOffsetInfo*>(target_base + sro_section.Offset());
for (size_t offset_index = 0; offset_index < num_string_offsets; ++offset_index) {
uint32_t base_offset = sro_base[offset_index].first;
uint32_t raw_member_offset = sro_base[offset_index].second;
DCHECK_ALIGNED(base_offset, 2);
DCHECK_ALIGNED(raw_member_offset, 2);
ObjPtr<mirror::Object> obj_ptr =
reinterpret_cast<mirror::Object*>(space->Begin() + base_offset);
MemberOffset member_offset(raw_member_offset);
ObjPtr<mirror::String> referred_string =
obj_ptr->GetFieldObject<mirror::String,
kVerifyNone,
kWithoutReadBarrier,
/* kIsVolatile= */ false>(member_offset);
DCHECK(referred_string != nullptr);
ObjPtr<mirror::String> visited = visitor(referred_string);
if (visited != referred_string) {
obj_ptr->SetFieldObject</* kTransactionActive= */ false,
/* kCheckTransaction= */ false,
kVerifyNone,
/* kIsVolatile= */ false>(member_offset, visited);
}
}
}
static void VerifyInternedStringReferences(gc::space::ImageSpace* space)
REQUIRES_SHARED(Locks::mutator_lock_) {
InternTable::UnorderedSet image_interns;
const ImageSection& section = space->GetImageHeader().GetInternedStringsSection();
if (section.Size() > 0) {
size_t read_count;
const uint8_t* data = space->Begin() + section.Offset();
InternTable::UnorderedSet image_set(data, /*make_copy_of_data=*/ false, &read_count);
image_set.swap(image_interns);
}
size_t num_recorded_refs = 0u;
VisitInternedStringReferences(
space,
[&image_interns, &num_recorded_refs](ObjPtr<mirror::String> str)
REQUIRES_SHARED(Locks::mutator_lock_) {
auto it = image_interns.find(GcRoot<mirror::String>(str));
CHECK(it != image_interns.end());
CHECK(it->Read() == str);
++num_recorded_refs;
return str;
});
size_t num_found_refs = CountInternedStringReferences(*space, image_interns);
CHECK_EQ(num_recorded_refs, num_found_refs);
}
// new_class_set is the set of classes that were read from the class table section in the image.
// If there was no class table section, it is null.
// Note: using a class here to avoid having to make ClassLinker internals public.
class AppImageLoadingHelper {
public:
static void Update(
ClassLinker* class_linker,
gc::space::ImageSpace* space,
Handle<mirror::ClassLoader> class_loader,
Handle<mirror::ObjectArray<mirror::DexCache>> dex_caches)
REQUIRES(!Locks::dex_lock_)
REQUIRES_SHARED(Locks::mutator_lock_);
static void HandleAppImageStrings(gc::space::ImageSpace* space)
REQUIRES_SHARED(Locks::mutator_lock_);
};
void AppImageLoadingHelper::Update(
ClassLinker* class_linker,
gc::space::ImageSpace* space,
Handle<mirror::ClassLoader> class_loader,
Handle<mirror::ObjectArray<mirror::DexCache>> dex_caches)
REQUIRES(!Locks::dex_lock_)
REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedTrace app_image_timing("AppImage:Updating");
if (kIsDebugBuild && ClassLinker::kAppImageMayContainStrings) {
// In debug build, verify the string references before applying
// the Runtime::LoadAppImageStartupCache() option.
VerifyInternedStringReferences(space);
}
Thread* const self = Thread::Current();
Runtime* const runtime = Runtime::Current();
gc::Heap* const heap = runtime->GetHeap();
const ImageHeader& header = space->GetImageHeader();
{
// Register dex caches with the class loader.
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
for (auto dex_cache : dex_caches.Iterate<mirror::DexCache>()) {
const DexFile* const dex_file = dex_cache->GetDexFile();
{
WriterMutexLock mu2(self, *Locks::dex_lock_);
CHECK(class_linker->FindDexCacheDataLocked(*dex_file) == nullptr);
class_linker->RegisterDexFileLocked(*dex_file, dex_cache, class_loader.Get());
}
}
}
if (ClassLinker::kAppImageMayContainStrings) {
HandleAppImageStrings(space);
}
if (kVerifyArtMethodDeclaringClasses) {
ScopedTrace timing("AppImage:VerifyDeclaringClasses");
ReaderMutexLock rmu(self, *Locks::heap_bitmap_lock_);
gc::accounting::HeapBitmap* live_bitmap = heap->GetLiveBitmap();
header.VisitPackedArtMethods([&](ArtMethod& method)
REQUIRES_SHARED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
ObjPtr<mirror::Class> klass = method.GetDeclaringClassUnchecked();
if (klass != nullptr) {
CHECK(live_bitmap->Test(klass.Ptr())) << "Image method has unmarked declaring class";
}
}, space->Begin(), kRuntimePointerSize);
}
}
void AppImageLoadingHelper::HandleAppImageStrings(gc::space::ImageSpace* space) {
// Iterate over the string reference offsets stored in the image and intern
// the strings they point to.
ScopedTrace timing("AppImage:InternString");
Runtime* const runtime = Runtime::Current();
InternTable* const intern_table = runtime->GetInternTable();
// Add the intern table, removing any conflicts. For conflicts, store the new address in a map
// for faster lookup.
// TODO: Optimize with a bitmap or bloom filter
SafeMap<mirror::String*, mirror::String*> intern_remap;
auto func = [&](InternTable::UnorderedSet& interns)
REQUIRES_SHARED(Locks::mutator_lock_)
REQUIRES(Locks::intern_table_lock_) {
const size_t non_boot_image_strings = intern_table->CountInterns(
/*visit_boot_images=*/false,
/*visit_non_boot_images=*/true);
VLOG(image) << "AppImage:stringsInInternTableSize = " << interns.size();
VLOG(image) << "AppImage:nonBootImageInternStrings = " << non_boot_image_strings;
// Visit the smaller of the two sets to compute the intersection.
if (interns.size() < non_boot_image_strings) {
for (auto it = interns.begin(); it != interns.end(); ) {
ObjPtr<mirror::String> string = it->Read();
ObjPtr<mirror::String> existing = intern_table->LookupWeakLocked(string);
if (existing == nullptr) {
existing = intern_table->LookupStrongLocked(string);
}
if (existing != nullptr) {
intern_remap.Put(string.Ptr(), existing.Ptr());
it = interns.erase(it);
} else {
++it;
}
}
} else {
intern_table->VisitInterns([&](const GcRoot<mirror::String>& root)
REQUIRES_SHARED(Locks::mutator_lock_)
REQUIRES(Locks::intern_table_lock_) {
auto it = interns.find(root);
if (it != interns.end()) {
ObjPtr<mirror::String> existing = root.Read();
intern_remap.Put(it->Read(), existing.Ptr());
it = interns.erase(it);
}
}, /*visit_boot_images=*/false, /*visit_non_boot_images=*/true);
}
// Consistency check to ensure correctness.
if (kIsDebugBuild) {
for (GcRoot<mirror::String>& root : interns) {
ObjPtr<mirror::String> string = root.Read();
CHECK(intern_table->LookupWeakLocked(string) == nullptr) << string->ToModifiedUtf8();
CHECK(intern_table->LookupStrongLocked(string) == nullptr) << string->ToModifiedUtf8();
}
}
};
intern_table->AddImageStringsToTable(space, func);
if (!intern_remap.empty()) {
VLOG(image) << "AppImage:conflictingInternStrings = " << intern_remap.size();
VisitInternedStringReferences(
space,
[&intern_remap](ObjPtr<mirror::String> str) REQUIRES_SHARED(Locks::mutator_lock_) {
auto it = intern_remap.find(str.Ptr());
if (it != intern_remap.end()) {
return ObjPtr<mirror::String>(it->second);
}
return str;
});
}
}
static std::unique_ptr<const DexFile> OpenOatDexFile(const OatFile* oat_file,
const char* location,
std::string* error_msg)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(error_msg != nullptr);
std::unique_ptr<const DexFile> dex_file;
const OatDexFile* oat_dex_file = oat_file->GetOatDexFile(location, nullptr, error_msg);
if (oat_dex_file == nullptr) {
return std::unique_ptr<const DexFile>();
}
std::string inner_error_msg;
dex_file = oat_dex_file->OpenDexFile(&inner_error_msg);
if (dex_file == nullptr) {
*error_msg = StringPrintf("Failed to open dex file %s from within oat file %s error '%s'",
location,
oat_file->GetLocation().c_str(),
inner_error_msg.c_str());
return std::unique_ptr<const DexFile>();
}
if (dex_file->GetLocationChecksum() != oat_dex_file->GetDexFileLocationChecksum()) {
*error_msg = StringPrintf("Checksums do not match for %s: %x vs %x",
location,
dex_file->GetLocationChecksum(),
oat_dex_file->GetDexFileLocationChecksum());
return std::unique_ptr<const DexFile>();
}
return dex_file;
}
bool ClassLinker::OpenImageDexFiles(gc::space::ImageSpace* space,
std::vector<std::unique_ptr<const DexFile>>* out_dex_files,
std::string* error_msg) {
ScopedAssertNoThreadSuspension nts(__FUNCTION__);
const ImageHeader& header = space->GetImageHeader();
ObjPtr<mirror::Object> dex_caches_object = header.GetImageRoot(ImageHeader::kDexCaches);
DCHECK(dex_caches_object != nullptr);
ObjPtr<mirror::ObjectArray<mirror::DexCache>> dex_caches =
dex_caches_object->AsObjectArray<mirror::DexCache>();
const OatFile* oat_file = space->GetOatFile();
for (auto dex_cache : dex_caches->Iterate()) {
std::string dex_file_location(dex_cache->GetLocation()->ToModifiedUtf8());
std::unique_ptr<const DexFile> dex_file = OpenOatDexFile(oat_file,
dex_file_location.c_str(),
error_msg);
if (dex_file == nullptr) {
return false;
}
dex_cache->SetDexFile(dex_file.get());
out_dex_files->push_back(std::move(dex_file));
}
return true;
}
// Helper class for ArtMethod checks when adding an image. Keeps all required functionality
// together and caches some intermediate results.
class ImageChecker final {
public:
static void CheckObjects(gc::Heap* heap, ClassLinker* class_linker)
REQUIRES_SHARED(Locks::mutator_lock_) {
ImageChecker ic(heap, class_linker);
auto visitor = [&](mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(obj != nullptr);
CHECK(obj->GetClass() != nullptr) << "Null class in object " << obj;
CHECK(obj->GetClass()->GetClass() != nullptr) << "Null class class " << obj;
if (obj->IsClass()) {
auto klass = obj->AsClass();
for (ArtField& field : klass->GetIFields()) {
CHECK_EQ(field.GetDeclaringClass(), klass);
}
for (ArtField& field : klass->GetSFields()) {
CHECK_EQ(field.GetDeclaringClass(), klass);
}
const PointerSize pointer_size = ic.pointer_size_;
for (ArtMethod& m : klass->GetMethods(pointer_size)) {
ic.CheckArtMethod(&m, klass);
}
ObjPtr<mirror::PointerArray> vtable = klass->GetVTable();
if (vtable != nullptr) {
ic.CheckArtMethodPointerArray(vtable, nullptr);
}
if (klass->ShouldHaveImt()) {
ImTable* imt = klass->GetImt(pointer_size);
for (size_t i = 0; i < ImTable::kSize; ++i) {
ic.CheckArtMethod(imt->Get(i, pointer_size), nullptr);
}
}
if (klass->ShouldHaveEmbeddedVTable()) {
for (int32_t i = 0; i < klass->GetEmbeddedVTableLength(); ++i) {
ic.CheckArtMethod(klass->GetEmbeddedVTableEntry(i, pointer_size), nullptr);
}
}
ObjPtr<mirror::IfTable> iftable = klass->GetIfTable();
for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
if (iftable->GetMethodArrayCount(i) > 0) {
ic.CheckArtMethodPointerArray(iftable->GetMethodArray(i), nullptr);
}
}
}
};
heap->VisitObjects(visitor);
}
private:
ImageChecker(gc::Heap* heap, ClassLinker* class_linker)
: spaces_(heap->GetBootImageSpaces()),
pointer_size_(class_linker->GetImagePointerSize()) {
space_begin_.reserve(spaces_.size());
method_sections_.reserve(spaces_.size());
runtime_method_sections_.reserve(spaces_.size());
for (gc::space::ImageSpace* space : spaces_) {
space_begin_.push_back(space->Begin());
auto& header = space->GetImageHeader();
method_sections_.push_back(&header.GetMethodsSection());
runtime_method_sections_.push_back(&header.GetRuntimeMethodsSection());
}
}
void CheckArtMethod(ArtMethod* m, ObjPtr<mirror::Class> expected_class)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (m->IsRuntimeMethod()) {
ObjPtr<mirror::Class> declaring_class = m->GetDeclaringClassUnchecked();
CHECK(declaring_class == nullptr) << declaring_class << " " << m->PrettyMethod();
} else if (m->IsCopied()) {
CHECK(m->GetDeclaringClass() != nullptr) << m->PrettyMethod();
} else if (expected_class != nullptr) {
CHECK_EQ(m->GetDeclaringClassUnchecked(), expected_class) << m->PrettyMethod();
}
if (!spaces_.empty()) {
bool contains = false;
for (size_t i = 0; !contains && i != space_begin_.size(); ++i) {
const size_t offset = reinterpret_cast<uint8_t*>(m) - space_begin_[i];
contains = method_sections_[i]->Contains(offset) ||
runtime_method_sections_[i]->Contains(offset);
}
CHECK(contains) << m << " not found";
}
}
void CheckArtMethodPointerArray(ObjPtr<mirror::PointerArray> arr,
ObjPtr<mirror::Class> expected_class)
REQUIRES_SHARED(Locks::mutator_lock_) {
CHECK(arr != nullptr);
for (int32_t j = 0; j < arr->GetLength(); ++j) {
auto* method = arr->GetElementPtrSize<ArtMethod*>(j, pointer_size_);
// expected_class == null means we are a dex cache.
if (expected_class != nullptr) {
CHECK(method != nullptr);
}
if (method != nullptr) {
CheckArtMethod(method, expected_class);
}
}
}
const std::vector<gc::space::ImageSpace*>& spaces_;
const PointerSize pointer_size_;
// Cached sections from the spaces.
std::vector<const uint8_t*> space_begin_;
std::vector<const ImageSection*> method_sections_;
std::vector<const ImageSection*> runtime_method_sections_;
};
static void VerifyAppImage(const ImageHeader& header,
const Handle<mirror::ClassLoader>& class_loader,
ClassTable* class_table,
gc::space::ImageSpace* space)
REQUIRES_SHARED(Locks::mutator_lock_) {
header.VisitPackedArtMethods([&](ArtMethod& method) REQUIRES_SHARED(Locks::mutator_lock_) {
ObjPtr<mirror::Class> klass = method.GetDeclaringClass();
if (klass != nullptr && !Runtime::Current()->GetHeap()->ObjectIsInBootImageSpace(klass)) {
CHECK_EQ(class_table->LookupByDescriptor(klass), klass)
<< mirror::Class::PrettyClass(klass);
}
}, space->Begin(), kRuntimePointerSize);
{
// Verify that all direct interfaces of classes in the class table are also resolved.
std::vector<ObjPtr<mirror::Class>> classes;
auto verify_direct_interfaces_in_table = [&](ObjPtr<mirror::Class> klass)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (!klass->IsPrimitive() && klass->GetClassLoader() == class_loader.Get()) {
classes.push_back(klass);
}
return true;
};
class_table->Visit(verify_direct_interfaces_in_table);
for (ObjPtr<mirror::Class> klass : classes) {
for (uint32_t i = 0, num = klass->NumDirectInterfaces(); i != num; ++i) {
CHECK(klass->GetDirectInterface(i) != nullptr)
<< klass->PrettyDescriptor() << " iface #" << i;
}
}
}
}
bool ClassLinker::AddImageSpace(
gc::space::ImageSpace* space,
Handle<mirror::ClassLoader> class_loader,
std::vector<std::unique_ptr<const DexFile>>* out_dex_files,
std::string* error_msg) {
DCHECK(out_dex_files != nullptr);
DCHECK(error_msg != nullptr);
const uint64_t start_time = NanoTime();
const bool app_image = class_loader != nullptr;
const ImageHeader& header = space->GetImageHeader();
ObjPtr<mirror::Object> dex_caches_object = header.GetImageRoot(ImageHeader::kDexCaches);
DCHECK(dex_caches_object != nullptr);
Runtime* const runtime = Runtime::Current();
gc::Heap* const heap = runtime->GetHeap();
Thread* const self = Thread::Current();
// Check that the image is what we are expecting.
if (image_pointer_size_ != space->GetImageHeader().GetPointerSize()) {
*error_msg = StringPrintf("Application image pointer size does not match runtime: %zu vs %zu",
static_cast<size_t>(space->GetImageHeader().GetPointerSize()),
image_pointer_size_);
return false;
}
size_t expected_image_roots = ImageHeader::NumberOfImageRoots(app_image);
if (static_cast<size_t>(header.GetImageRoots()->GetLength()) != expected_image_roots) {
*error_msg = StringPrintf("Expected %zu image roots but got %d",
expected_image_roots,
header.GetImageRoots()->GetLength());
return false;
}
StackHandleScope<3> hs(self);
Handle<mirror::ObjectArray<mirror::DexCache>> dex_caches(
hs.NewHandle(dex_caches_object->AsObjectArray<mirror::DexCache>()));
Handle<mirror::ObjectArray<mirror::Class>> class_roots(hs.NewHandle(
header.GetImageRoot(ImageHeader::kClassRoots)->AsObjectArray<mirror::Class>()));
MutableHandle<mirror::ClassLoader> image_class_loader(hs.NewHandle(
app_image ? header.GetImageRoot(ImageHeader::kAppImageClassLoader)->AsClassLoader()
: nullptr));
DCHECK(class_roots != nullptr);
if (class_roots->GetLength() != static_cast<int32_t>(ClassRoot::kMax)) {
*error_msg = StringPrintf("Expected %d class roots but got %d",
class_roots->GetLength(),
static_cast<int32_t>(ClassRoot::kMax));
return false;
}
// Check against existing class roots to make sure they match the ones in the boot image.
ObjPtr<mirror::ObjectArray<mirror::Class>> existing_class_roots = GetClassRoots();
for (size_t i = 0; i < static_cast<size_t>(ClassRoot::kMax); i++) {
if (class_roots->Get(i) != GetClassRoot(static_cast<ClassRoot>(i), existing_class_roots)) {
*error_msg = "App image class roots must have pointer equality with runtime ones.";
return false;
}
}
const OatFile* oat_file = space->GetOatFile();
if (oat_file->GetOatHeader().GetDexFileCount() !=
static_cast<uint32_t>(dex_caches->GetLength())) {
*error_msg = "Dex cache count and dex file count mismatch while trying to initialize from "
"image";
return false;
}
for (auto dex_cache : dex_caches.Iterate<mirror::DexCache>()) {
std::string dex_file_location = dex_cache->GetLocation()->ToModifiedUtf8();
std::unique_ptr<const DexFile> dex_file = OpenOatDexFile(oat_file,
dex_file_location.c_str(),
error_msg);
if (dex_file == nullptr) {
return false;
}
{
// Native fields are all null. Initialize them.
WriterMutexLock mu(self, *Locks::dex_lock_);
dex_cache->Initialize(dex_file.get(), class_loader.Get());
}
if (!app_image) {
// Register dex files, keep track of existing ones that are conflicts.
AppendToBootClassPath(dex_file.get(), dex_cache);
}
out_dex_files->push_back(std::move(dex_file));
}
if (app_image) {
ScopedObjectAccessUnchecked soa(Thread::Current());
ScopedAssertNoThreadSuspension sants("Checking app image", soa.Self());
if (IsBootClassLoader(soa, image_class_loader.Get())) {
*error_msg = "Unexpected BootClassLoader in app image";
return false;
}
}
if (kCheckImageObjects) {
if (!app_image) {
ImageChecker::CheckObjects(heap, this);
}
}
// Set entry point to interpreter if in InterpretOnly mode.
if (!runtime->IsAotCompiler() && runtime->GetInstrumentation()->InterpretOnly()) {
// Set image methods' entry point to interpreter.
header.VisitPackedArtMethods([&](ArtMethod& method) REQUIRES_SHARED(Locks::mutator_lock_) {
if (!method.IsRuntimeMethod()) {
DCHECK(method.GetDeclaringClass() != nullptr);
if (!method.IsNative() && !method.IsResolutionMethod()) {
method.SetEntryPointFromQuickCompiledCodePtrSize(GetQuickToInterpreterBridge(),
image_pointer_size_);
}
}
}, space->Begin(), image_pointer_size_);
}
if (!runtime->IsAotCompiler()) {
ScopedTrace trace("AppImage:UpdateCodeItemAndNterp");
bool can_use_nterp = interpreter::CanRuntimeUseNterp();
uint16_t hotness_threshold = runtime->GetJITOptions()->GetWarmupThreshold();
header.VisitPackedArtMethods([&](ArtMethod& method) REQUIRES_SHARED(Locks::mutator_lock_) {
// In the image, the `data` pointer field of the ArtMethod contains the code
// item offset. Change this to the actual pointer to the code item.
if (method.HasCodeItem()) {
const dex::CodeItem* code_item = method.GetDexFile()->GetCodeItem(
reinterpret_cast32<uint32_t>(method.GetDataPtrSize(image_pointer_size_)));
method.SetCodeItem(code_item);
// The hotness counter may have changed since we compiled the image, so
// reset it with the runtime value.
method.ResetCounter(hotness_threshold);
}
// Set image methods' entry point that point to the interpreter bridge to the
// nterp entry point.
if (method.GetEntryPointFromQuickCompiledCode() == nterp_trampoline_) {
if (can_use_nterp) {
DCHECK(!NeedsClinitCheckBeforeCall(&method) ||
method.GetDeclaringClass()->IsVisiblyInitialized());
method.SetEntryPointFromQuickCompiledCode(interpreter::GetNterpEntryPoint());
} else {
method.SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
}
}
}, space->Begin(), image_pointer_size_);
}
if (runtime->IsVerificationSoftFail()) {
header.VisitPackedArtMethods([&](ArtMethod& method) REQUIRES_SHARED(Locks::mutator_lock_) {
if (!method.IsNative() && method.IsInvokable()) {
method.ClearSkipAccessChecks();
}
}, space->Begin(), image_pointer_size_);
}
ClassTable* class_table = nullptr;
{
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
class_table = InsertClassTableForClassLoader(class_loader.Get());
}
// If we have a class table section, read it and use it for verification in
// UpdateAppImageClassLoadersAndDexCaches.
ClassTable::ClassSet temp_set;
const ImageSection& class_table_section = header.GetClassTableSection();
const bool added_class_table = class_table_section.Size() > 0u;
if (added_class_table) {
const uint64_t start_time2 = NanoTime();
size_t read_count = 0;
temp_set = ClassTable::ClassSet(space->Begin() + class_table_section.Offset(),
/*make copy*/false,
&read_count);
VLOG(image) << "Adding class table classes took " << PrettyDuration(NanoTime() - start_time2);
}
if (app_image) {
AppImageLoadingHelper::Update(this, space, class_loader, dex_caches);
{
ScopedTrace trace("AppImage:UpdateClassLoaders");
// Update class loader and resolved strings. If added_class_table is false, the resolved
// strings were forwarded UpdateAppImageClassLoadersAndDexCaches.
ObjPtr<mirror::ClassLoader> loader(class_loader.Get());
for (const ClassTable::TableSlot& root : temp_set) {
// Note: We probably don't need the read barrier unless we copy the app image objects into
// the region space.
ObjPtr<mirror::Class> klass(root.Read());
// Do not update class loader for boot image classes where the app image
// class loader is only the initiating loader but not the defining loader.
// Avoid read barrier since we are comparing against null.
if (klass->GetClassLoader<kDefaultVerifyFlags, kWithoutReadBarrier>() != nullptr) {
klass->SetClassLoader(loader);
}
}
}
if (kBitstringSubtypeCheckEnabled) {
// Every class in the app image has initially SubtypeCheckInfo in the
// Uninitialized state.
//
// The SubtypeCheck invariants imply that a SubtypeCheckInfo is at least Initialized
// after class initialization is complete. The app image ClassStatus as-is
// are almost all ClassStatus::Initialized, and being in the
// SubtypeCheckInfo::kUninitialized state is violating that invariant.
//
// Force every app image class's SubtypeCheck to be at least kIninitialized.
//
// See also ImageWriter::FixupClass.
ScopedTrace trace("AppImage:RecacluateSubtypeCheckBitstrings");
MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
for (const ClassTable::TableSlot& root : temp_set) {
SubtypeCheck<ObjPtr<mirror::Class>>::EnsureInitialized(root.Read());
}
}
}
if (!oat_file->GetBssGcRoots().empty()) {
// Insert oat file to class table for visiting .bss GC roots.
class_table->InsertOatFile(oat_file);
}
if (added_class_table) {
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
class_table->AddClassSet(std::move(temp_set));
}
if (kIsDebugBuild && app_image) {
// This verification needs to happen after the classes have been added to the class loader.
// Since it ensures classes are in the class table.
ScopedTrace trace("AppImage:Verify");
VerifyAppImage(header, class_loader, class_table, space);
}
VLOG(class_linker) << "Adding image space took " << PrettyDuration(NanoTime() - start_time);
return true;
}
void ClassLinker::VisitClassRoots(RootVisitor* visitor, VisitRootFlags flags) {
// Acquire tracing_enabled before locking class linker lock to prevent lock order violation. Since
// enabling tracing requires the mutator lock, there are no race conditions here.
const bool tracing_enabled = Trace::IsTracingEnabled();
Thread* const self = Thread::Current();
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
if (kUseReadBarrier) {
// We do not track new roots for CC.
DCHECK_EQ(0, flags & (kVisitRootFlagNewRoots |
kVisitRootFlagClearRootLog |
kVisitRootFlagStartLoggingNewRoots |
kVisitRootFlagStopLoggingNewRoots));
}
if ((flags & kVisitRootFlagAllRoots) != 0) {
// Argument for how root visiting deals with ArtField and ArtMethod roots.
// There is 3 GC cases to handle:
// Non moving concurrent:
// This case is easy to handle since the reference members of ArtMethod and ArtFields are held
// live by the class and class roots.
//
// Moving non-concurrent:
// This case needs to call visit VisitNativeRoots in case the classes or dex cache arrays move.
// To prevent missing roots, this case needs to ensure that there is no
// suspend points between the point which we allocate ArtMethod arrays and place them in a
// class which is in the class table.
//
// Moving concurrent:
// Need to make sure to not copy ArtMethods without doing read barriers since the roots are
// marked concurrently and we don't hold the classlinker_classes_lock_ when we do the copy.
//
// Use an unbuffered visitor since the class table uses a temporary GcRoot for holding decoded
// ClassTable::TableSlot. The buffered root visiting would access a stale stack location for
// these objects.
UnbufferedRootVisitor root_visitor(visitor, RootInfo(kRootStickyClass));
boot_class_table_->VisitRoots(root_visitor);
// If tracing is enabled, then mark all the class loaders to prevent unloading.
if ((flags & kVisitRootFlagClassLoader) != 0 || tracing_enabled) {
for (const ClassLoaderData& data : class_loaders_) {
GcRoot<mirror::Object> root(GcRoot<mirror::Object>(self->DecodeJObject(data.weak_root)));
root.VisitRoot(visitor, RootInfo(kRootVMInternal));
}
}
} else if (!kUseReadBarrier && (flags & kVisitRootFlagNewRoots) != 0) {
for (auto& root : new_class_roots_) {
ObjPtr<mirror::Class> old_ref = root.Read<kWithoutReadBarrier>();
root.VisitRoot(visitor, RootInfo(kRootStickyClass));
ObjPtr<mirror::Class> new_ref = root.Read<kWithoutReadBarrier>();
// Concurrent moving GC marked new roots through the to-space invariant.
CHECK_EQ(new_ref, old_ref);
}
for (const OatFile* oat_file : new_bss_roots_boot_oat_files_) {
for (GcRoot<mirror::Object>& root : oat_file->GetBssGcRoots()) {
ObjPtr<mirror::Object> old_ref = root.Read<kWithoutReadBarrier>();
if (old_ref != nullptr) {
DCHECK(old_ref->IsClass());
root.VisitRoot(visitor, RootInfo(kRootStickyClass));
ObjPtr<mirror::Object> new_ref = root.Read<kWithoutReadBarrier>();
// Concurrent moving GC marked new roots through the to-space invariant.
CHECK_EQ(new_ref, old_ref);
}
}
}
}
if (!kUseReadBarrier && (flags & kVisitRootFlagClearRootLog) != 0) {
new_class_roots_.clear();
new_bss_roots_boot_oat_files_.clear();
}
if (!kUseReadBarrier && (flags & kVisitRootFlagStartLoggingNewRoots) != 0) {
log_new_roots_ = true;
} else if (!kUseReadBarrier && (flags & kVisitRootFlagStopLoggingNewRoots) != 0) {
log_new_roots_ = false;
}
// We deliberately ignore the class roots in the image since we
// handle image roots by using the MS/CMS rescanning of dirty cards.
}
// Keep in sync with InitCallback. Anything we visit, we need to
// reinit references to when reinitializing a ClassLinker from a
// mapped image.
void ClassLinker::VisitRoots(RootVisitor* visitor, VisitRootFlags flags) {
class_roots_.VisitRootIfNonNull(visitor, RootInfo(kRootVMInternal));
VisitClassRoots(visitor, flags);
// Instead of visiting the find_array_class_cache_ drop it so that it doesn't prevent class
// unloading if we are marking roots.
DropFindArrayClassCache();
}
class VisitClassLoaderClassesVisitor : public ClassLoaderVisitor {
public:
explicit VisitClassLoaderClassesVisitor(ClassVisitor* visitor)
: visitor_(visitor),
done_(false) {}
void Visit(ObjPtr<mirror::ClassLoader> class_loader)
REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_) override {
ClassTable* const class_table = class_loader->GetClassTable();
if (!done_ && class_table != nullptr) {
DefiningClassLoaderFilterVisitor visitor(class_loader, visitor_);
if (!class_table->Visit(visitor)) {
// If the visitor ClassTable returns false it means that we don't need to continue.
done_ = true;
}
}
}
private:
// Class visitor that limits the class visits from a ClassTable to the classes with
// the provided defining class loader. This filter is used to avoid multiple visits
// of the same class which can be recorded for multiple initiating class loaders.
class DefiningClassLoaderFilterVisitor : public ClassVisitor {
public:
DefiningClassLoaderFilterVisitor(ObjPtr<mirror::ClassLoader> defining_class_loader,
ClassVisitor* visitor)
: defining_class_loader_(defining_class_loader), visitor_(visitor) { }
bool operator()(ObjPtr<mirror::Class> klass) override REQUIRES_SHARED(Locks::mutator_lock_) {
if (klass->GetClassLoader() != defining_class_loader_) {
return true;
}
return (*visitor_)(klass);
}
const ObjPtr<mirror::ClassLoader> defining_class_loader_;
ClassVisitor* const visitor_;
};
ClassVisitor* const visitor_;
// If done is true then we don't need to do any more visiting.
bool done_;
};
void ClassLinker::VisitClassesInternal(ClassVisitor* visitor) {
if (boot_class_table_->Visit(*visitor)) {
VisitClassLoaderClassesVisitor loader_visitor(visitor);
VisitClassLoaders(&loader_visitor);
}
}
void ClassLinker::VisitClasses(ClassVisitor* visitor) {
Thread* const self = Thread::Current();
ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
// Not safe to have thread suspension when we are holding a lock.
if (self != nullptr) {
ScopedAssertNoThreadSuspension nts(__FUNCTION__);
VisitClassesInternal(visitor);
} else {
VisitClassesInternal(visitor);
}
}
class GetClassesInToVector : public ClassVisitor {
public:
bool operator()(ObjPtr<mirror::Class> klass) override {
classes_.push_back(klass);
return true;
}
std::vector<ObjPtr<mirror::Class>> classes_;
};
class GetClassInToObjectArray : public ClassVisitor {
public:
explicit GetClassInToObjectArray(mirror::ObjectArray<mirror::Class>* arr)
: arr_(arr), index_(0) {}
bool operator()(ObjPtr<mirror::Class> klass) override REQUIRES_SHARED(Locks::mutator_lock_) {
++index_;
if (index_ <= arr_->GetLength()) {
arr_->Set(index_ - 1, klass);
return true;
}
return false;
}
bool Succeeded() const REQUIRES_SHARED(Locks::mutator_lock_) {
return index_ <= arr_->GetLength();
}
private:
mirror::ObjectArray<mirror::Class>* const arr_;
int32_t index_;
};
void ClassLinker::VisitClassesWithoutClassesLock(ClassVisitor* visitor) {
// TODO: it may be possible to avoid secondary storage if we iterate over dex caches. The problem
// is avoiding duplicates.
if (!kMovingClasses) {
ScopedAssertNoThreadSuspension nts(__FUNCTION__);
GetClassesInToVector accumulator;
VisitClasses(&accumulator);
for (ObjPtr<mirror::Class> klass : accumulator.classes_) {
if (!visitor->operator()(klass)) {
return;
}
}
} else {
Thread* const self = Thread::Current();
StackHandleScope<1> hs(self);
auto classes = hs.NewHandle<mirror::ObjectArray<mirror::Class>>(nullptr);
// We size the array assuming classes won't be added to the class table during the visit.
// If this assumption fails we iterate again.
while (true) {
size_t class_table_size;
{
ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
// Add 100 in case new classes get loaded when we are filling in the object array.
class_table_size = NumZygoteClasses() + NumNonZygoteClasses() + 100;
}
ObjPtr<mirror::Class> array_of_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>(this);
classes.Assign(
mirror::ObjectArray<mirror::Class>::Alloc(self, array_of_class, class_table_size));
CHECK(classes != nullptr); // OOME.
GetClassInToObjectArray accumulator(classes.Get());
VisitClasses(&accumulator);
if (accumulator.Succeeded()) {
break;
}
}
for (int32_t i = 0; i < classes->GetLength(); ++i) {
// If the class table shrank during creation of the clases array we expect null elements. If
// the class table grew then the loop repeats. If classes are created after the loop has
// finished then we don't visit.
ObjPtr<mirror::Class> klass = classes->Get(i);
if (klass != nullptr && !visitor->operator()(klass)) {
return;
}
}
}
}
ClassLinker::~ClassLinker() {
Thread* const self = Thread::Current();
for (const ClassLoaderData& data : class_loaders_) {
// CHA unloading analysis is not needed. No negative consequences are expected because
// all the classloaders are deleted at the same time.
DeleteClassLoader(self, data, /*cleanup_cha=*/ false);
}
class_loaders_.clear();
while (!running_visibly_initialized_callbacks_.empty()) {
std::unique_ptr<VisiblyInitializedCallback> callback(
std::addressof(running_visibly_initialized_callbacks_.front()));
running_visibly_initialized_callbacks_.pop_front();
}
}
void ClassLinker::DeleteClassLoader(Thread* self, const ClassLoaderData& data, bool cleanup_cha) {
Runtime* const runtime = Runtime::Current();
JavaVMExt* const vm = runtime->GetJavaVM();
vm->DeleteWeakGlobalRef(self, data.weak_root);
// Notify the JIT that we need to remove the methods and/or profiling info.
if (runtime->GetJit() != nullptr) {
jit::JitCodeCache* code_cache = runtime->GetJit()->GetCodeCache();
if (code_cache != nullptr) {
// For the JIT case, RemoveMethodsIn removes the CHA dependencies.
code_cache->RemoveMethodsIn(self, *data.allocator);
}
} else if (cha_ != nullptr) {
// If we don't have a JIT, we need to manually remove the CHA dependencies manually.
cha_->RemoveDependenciesForLinearAlloc(data.allocator);
}
// Cleanup references to single implementation ArtMethods that will be deleted.
if (cleanup_cha) {
CHAOnDeleteUpdateClassVisitor visitor(data.allocator);
data.class_table->Visit<CHAOnDeleteUpdateClassVisitor, kWithoutReadBarrier>(visitor);
}
{
MutexLock lock(self, critical_native_code_with_clinit_check_lock_);
auto end = critical_native_code_with_clinit_check_.end();
for (auto it = critical_native_code_with_clinit_check_.begin(); it != end; ) {
if (data.allocator->ContainsUnsafe(it->first)) {
it = critical_native_code_with_clinit_check_.erase(it);
} else {
++it;
}
}
}
delete data.allocator;
delete data.class_table;
}
ObjPtr<mirror::PointerArray> ClassLinker::AllocPointerArray(Thread* self, size_t length) {
return ObjPtr<mirror::PointerArray>::DownCast(
image_pointer_size_ == PointerSize::k64
? ObjPtr<mirror::Array>(mirror::LongArray::Alloc(self, length))
: ObjPtr<mirror::Array>(mirror::IntArray::Alloc(self, length)));
}
ObjPtr<mirror::DexCache> ClassLinker::AllocDexCache(Thread* self, const DexFile& dex_file) {
StackHandleScope<1> hs(self);
auto dex_cache(hs.NewHandle(ObjPtr<mirror::DexCache>::DownCast(
GetClassRoot<mirror::DexCache>(this)->AllocObject(self))));
if (dex_cache == nullptr) {
self->AssertPendingOOMException();
return nullptr;
}
// Use InternWeak() so that the location String can be collected when the ClassLoader
// with this DexCache is collected.
ObjPtr<mirror::String> location = intern_table_->InternWeak(dex_file.GetLocation().c_str());
if (location == nullptr) {
self->AssertPendingOOMException();
return nullptr;
}
dex_cache->SetLocation(location);
return dex_cache.Get();
}
ObjPtr<mirror::DexCache> ClassLinker::AllocAndInitializeDexCache(
Thread* self, const DexFile& dex_file, ObjPtr<mirror::ClassLoader> class_loader) {
StackHandleScope<1> hs(self);
Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(class_loader));
ObjPtr<mirror::DexCache> dex_cache = AllocDexCache(self, dex_file);
if (dex_cache != nullptr) {
WriterMutexLock mu(self, *Locks::dex_lock_);
dex_cache->Initialize(&dex_file, h_class_loader.Get());
}
return dex_cache;
}
template <bool kMovable, typename PreFenceVisitor>
ObjPtr<mirror::Class> ClassLinker::AllocClass(Thread* self,
ObjPtr<mirror::Class> java_lang_Class,
uint32_t class_size,
const PreFenceVisitor& pre_fence_visitor) {
DCHECK_GE(class_size, sizeof(mirror::Class));
gc::Heap* heap = Runtime::Current()->GetHeap();
ObjPtr<mirror::Object> k = (kMovingClasses && kMovable) ?
heap->AllocObject(self, java_lang_Class, class_size, pre_fence_visitor) :
heap->AllocNonMovableObject(self, java_lang_Class, class_size, pre_fence_visitor);
if (UNLIKELY(k == nullptr)) {
self->AssertPendingOOMException();
return nullptr;
}
return k->AsClass();
}
template <bool kMovable>
ObjPtr<mirror::Class> ClassLinker::AllocClass(Thread* self,
ObjPtr<mirror::Class> java_lang_Class,
uint32_t class_size) {
mirror::Class::InitializeClassVisitor visitor(class_size);
return AllocClass<kMovable>(self, java_lang_Class, class_size, visitor);
}
ObjPtr<mirror::Class> ClassLinker::AllocClass(Thread* self, uint32_t class_size) {
return AllocClass(self, GetClassRoot<mirror::Class>(this), class_size);
}
void ClassLinker::AllocPrimitiveArrayClass(Thread* self,
ClassRoot primitive_root,
ClassRoot array_root) {
// We make this class non-movable for the unlikely case where it were to be
// moved by a sticky-bit (minor) collection when using the Generational
// Concurrent Copying (CC) collector, potentially creating a stale reference
// in the `klass_` field of one of its instances allocated in the Large-Object
// Space (LOS) -- see the comment about the dirty card scanning logic in
// art::gc::collector::ConcurrentCopying::MarkingPhase.
ObjPtr<mirror::Class> array_class = AllocClass</* kMovable= */ false>(
self, GetClassRoot<mirror::Class>(this), mirror::Array::ClassSize(image_pointer_size_));
ObjPtr<mirror::Class> component_type = GetClassRoot(primitive_root, this);
DCHECK(component_type->IsPrimitive());
array_class->SetComponentType(component_type);
SetClassRoot(array_root, array_class);
}
void ClassLinker::FinishArrayClassSetup(ObjPtr<mirror::Class> array_class) {
ObjPtr<mirror::Class> java_lang_Object = GetClassRoot<mirror::Object>(this);
array_class->SetSuperClass(java_lang_Object);
array_class->SetVTable(java_lang_Object->GetVTable());
array_class->SetPrimitiveType(Primitive::kPrimNot);
ObjPtr<mirror::Class> component_type = array_class->GetComponentType();
array_class->SetClassFlags(component_type->IsPrimitive()
? mirror::kClassFlagNoReferenceFields
: mirror::kClassFlagObjectArray);
array_class->SetClassLoader(component_type->GetClassLoader());
array_class->SetStatusForPrimitiveOrArray(ClassStatus::kLoaded);
array_class->PopulateEmbeddedVTable(image_pointer_size_);
ImTable* object_imt = java_lang_Object->GetImt(image_pointer_size_);
array_class->SetImt(object_imt, image_pointer_size_);
DCHECK_EQ(array_class->NumMethods(), 0u);
// don't need to set new_class->SetObjectSize(..)
// because Object::SizeOf delegates to Array::SizeOf
// All arrays have java/lang/Cloneable and java/io/Serializable as
// interfaces. We need to set that up here, so that stuff like
// "instanceof" works right.
// Use the single, global copies of "interfaces" and "iftable"
// (remember not to free them for arrays).
{
ObjPtr<mirror::IfTable> array_iftable = GetArrayIfTable();
CHECK(array_iftable != nullptr);
array_class->SetIfTable(array_iftable);
}
// Inherit access flags from the component type.
int access_flags = component_type->GetAccessFlags();
// Lose any implementation detail flags; in particular, arrays aren't finalizable.
access_flags &= kAccJavaFlagsMask;
// Arrays can't be used as a superclass or interface, so we want to add "abstract final"
// and remove "interface".
access_flags |= kAccAbstract | kAccFinal;
access_flags &= ~kAccInterface;
array_class->SetAccessFlagsDuringLinking(access_flags);
// Array classes are fully initialized either during single threaded startup,
// or from a pre-fence visitor, so visibly initialized.
array_class->SetStatusForPrimitiveOrArray(ClassStatus::kVisiblyInitialized);
}
void ClassLinker::FinishCoreArrayClassSetup(ClassRoot array_root) {
// Do not hold lock on the array class object, the initialization of
// core array classes is done while the process is still single threaded.
ObjPtr<mirror::Class> array_class = GetClassRoot(array_root, this);
FinishArrayClassSetup(array_class);
std::string temp;
const char* descriptor = array_class->GetDescriptor(&temp);
size_t hash = ComputeModifiedUtf8Hash(descriptor);
ObjPtr<mirror::Class> existing = InsertClass(descriptor, array_class, hash);
CHECK(existing == nullptr);
}
ObjPtr<mirror::ObjectArray<mirror::StackTraceElement>> ClassLinker::AllocStackTraceElementArray(
Thread* self,
size_t length) {
return mirror::ObjectArray<mirror::StackTraceElement>::Alloc(
self, GetClassRoot<mirror::ObjectArray<mirror::StackTraceElement>>(this), length);
}
ObjPtr<mirror::Class> ClassLinker::EnsureResolved(Thread* self,
const char* descriptor,
ObjPtr<mirror::Class> klass) {
DCHECK(klass != nullptr);
if (kIsDebugBuild) {
StackHandleScope<1> hs(self);
HandleWrapperObjPtr<mirror::Class> h = hs.NewHandleWrapper(&klass);
Thread::PoisonObjectPointersIfDebug();
}
// For temporary classes we must wait for them to be retired.
if (init_done_ && klass->IsTemp()) {
CHECK(!klass->IsResolved());
if (klass->IsErroneousUnresolved()) {
ThrowEarlierClassFailure(klass);
return nullptr;
}
StackHandleScope<1> hs(self);
Handle<mirror::Class> h_class(hs.NewHandle(klass));
ObjectLock<mirror::Class> lock(self, h_class);
// Loop and wait for the resolving thread to retire this class.
while (!h_class->IsRetired() && !h_class->IsErroneousUnresolved()) {
lock.WaitIgnoringInterrupts();
}
if (h_class->IsErroneousUnresolved()) {
ThrowEarlierClassFailure(h_class.Get());
return nullptr;
}
CHECK(h_class->IsRetired());
// Get the updated class from class table.
klass = LookupClass(self, descriptor, h_class.Get()->GetClassLoader());
}
// Wait for the class if it has not already been linked.
size_t index = 0;
// Maximum number of yield iterations until we start sleeping.
static const size_t kNumYieldIterations = 1000;
// How long each sleep is in us.
static const size_t kSleepDurationUS = 1000; // 1 ms.
while (!klass->IsResolved() && !klass->IsErroneousUnresolved()) {
StackHandleScope<1> hs(self);
HandleWrapperObjPtr<mirror::Class> h_class(hs.NewHandleWrapper(&klass));
{
ObjectTryLock<mirror::Class> lock(self, h_class);
// Can not use a monitor wait here since it may block when returning and deadlock if another
// thread has locked klass.
if (lock.Acquired()) {
// Check for circular dependencies between classes, the lock is required for SetStatus.
if (!h_class->IsResolved() && h_class->GetClinitThreadId() == self->GetTid()) {
ThrowClassCircularityError(h_class.Get());
mirror::Class::SetStatus(h_class, ClassStatus::kErrorUnresolved, self);
return nullptr;
}
}
}
{
// Handle wrapper deals with klass moving.
ScopedThreadSuspension sts(self, ThreadState::kSuspended);
if (index < kNumYieldIterations) {
sched_yield();
} else {
usleep(kSleepDurationUS);
}
}
++index;
}
if (klass->IsErroneousUnresolved()) {
ThrowEarlierClassFailure(klass);
return nullptr;
}
// Return the loaded class. No exceptions should be pending.
CHECK(klass->IsResolved()) << klass->PrettyClass();
self->AssertNoPendingException();
return klass;
}
using ClassPathEntry = std::pair<const DexFile*, const dex::ClassDef*>;
// Search a collection of DexFiles for a descriptor
ClassPathEntry FindInClassPath(const char* descriptor,
size_t hash, const std::vector<const DexFile*>& class_path) {
for (const DexFile* dex_file : class_path) {
DCHECK(dex_file != nullptr);
const dex::ClassDef* dex_class_def = OatDexFile::FindClassDef(*dex_file, descriptor, hash);
if (dex_class_def != nullptr) {
return ClassPathEntry(dex_file, dex_class_def);
}
}
return ClassPathEntry(nullptr, nullptr);
}
// Helper macro to make sure each class loader lookup call handles the case the
// class loader is not recognized, or the lookup threw an exception.
#define RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(call_, result_, thread_) \
do { \
auto local_call = call_; \
if (!local_call) { \
return false; \
} \
auto local_result = result_; \
if (local_result != nullptr) { \
return true; \
} \
auto local_thread = thread_; \
if (local_thread->IsExceptionPending()) { \
/* Pending exception means there was an error other than */ \
/* ClassNotFound that must be returned to the caller. */ \
return false; \
} \
} while (0)
bool ClassLinker::FindClassInSharedLibraries(ScopedObjectAccessAlreadyRunnable& soa,
Thread* self,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader,
/*out*/ ObjPtr<mirror::Class>* result) {
ArtField* field =
jni::DecodeArtField(WellKnownClasses::dalvik_system_BaseDexClassLoader_sharedLibraryLoaders);
return FindClassInSharedLibrariesHelper(soa, self, descriptor, hash, class_loader, field, result);
}
bool ClassLinker::FindClassInSharedLibrariesHelper(ScopedObjectAccessAlreadyRunnable& soa,
Thread* self,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader,
ArtField* field,
/*out*/ ObjPtr<mirror::Class>* result) {
ObjPtr<mirror::Object> raw_shared_libraries = field->GetObject(class_loader.Get());
if (raw_shared_libraries == nullptr) {
return true;
}
StackHandleScope<2> hs(self);
Handle<mirror::ObjectArray<mirror::ClassLoader>> shared_libraries(
hs.NewHandle(raw_shared_libraries->AsObjectArray<mirror::ClassLoader>()));
MutableHandle<mirror::ClassLoader> temp_loader = hs.NewHandle<mirror::ClassLoader>(nullptr);
for (auto loader : shared_libraries.Iterate<mirror::ClassLoader>()) {
temp_loader.Assign(loader);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBaseDexClassLoader(soa, self, descriptor, hash, temp_loader, result),
*result,
self);
}
return true;
}
bool ClassLinker::FindClassInSharedLibrariesAfter(ScopedObjectAccessAlreadyRunnable& soa,
Thread* self,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader,
/*out*/ ObjPtr<mirror::Class>* result) {
ArtField* field = jni::DecodeArtField(
WellKnownClasses::dalvik_system_BaseDexClassLoader_sharedLibraryLoadersAfter);
return FindClassInSharedLibrariesHelper(soa, self, descriptor, hash, class_loader, field, result);
}
bool ClassLinker::FindClassInBaseDexClassLoader(ScopedObjectAccessAlreadyRunnable& soa,
Thread* self,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader,
/*out*/ ObjPtr<mirror::Class>* result) {
// Termination case: boot class loader.
if (IsBootClassLoader(soa, class_loader.Get())) {
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBootClassLoaderClassPath(self, descriptor, hash, result), *result, self);
return true;
}
if (IsPathOrDexClassLoader(soa, class_loader) || IsInMemoryDexClassLoader(soa, class_loader)) {
// For regular path or dex class loader the search order is:
// - parent
// - shared libraries
// - class loader dex files
// Create a handle as RegisterDexFile may allocate dex caches (and cause thread suspension).
StackHandleScope<1> hs(self);
Handle<mirror::ClassLoader> h_parent(hs.NewHandle(class_loader->GetParent()));
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBaseDexClassLoader(soa, self, descriptor, hash, h_parent, result),
*result,
self);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInSharedLibraries(soa, self, descriptor, hash, class_loader, result),
*result,
self);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBaseDexClassLoaderClassPath(soa, descriptor, hash, class_loader, result),
*result,
self);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInSharedLibrariesAfter(soa, self, descriptor, hash, class_loader, result),
*result,
self);
// We did not find a class, but the class loader chain was recognized, so we
// return true.
return true;
}
if (IsDelegateLastClassLoader(soa, class_loader)) {
// For delegate last, the search order is:
// - boot class path
// - shared libraries
// - class loader dex files
// - parent
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBootClassLoaderClassPath(self, descriptor, hash, result), *result, self);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInSharedLibraries(soa, self, descriptor, hash, class_loader, result),
*result,
self);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBaseDexClassLoaderClassPath(soa, descriptor, hash, class_loader, result),
*result,
self);
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInSharedLibrariesAfter(soa, self, descriptor, hash, class_loader, result),
*result,
self);
// Create a handle as RegisterDexFile may allocate dex caches (and cause thread suspension).
StackHandleScope<1> hs(self);
Handle<mirror::ClassLoader> h_parent(hs.NewHandle(class_loader->GetParent()));
RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION(
FindClassInBaseDexClassLoader(soa, self, descriptor, hash, h_parent, result),
*result,
self);
// We did not find a class, but the class loader chain was recognized, so we
// return true.
return true;
}
// Unsupported class loader.
*result = nullptr;
return false;
}
#undef RETURN_IF_UNRECOGNIZED_OR_FOUND_OR_EXCEPTION
namespace {
// Matches exceptions caught in DexFile.defineClass.
ALWAYS_INLINE bool MatchesDexFileCaughtExceptions(ObjPtr<mirror::Throwable> throwable,
ClassLinker* class_linker)
REQUIRES_SHARED(Locks::mutator_lock_) {
return
// ClassNotFoundException.
throwable->InstanceOf(GetClassRoot(ClassRoot::kJavaLangClassNotFoundException,
class_linker))
||
// NoClassDefFoundError. TODO: Reconsider this. b/130746382.
throwable->InstanceOf(Runtime::Current()->GetPreAllocatedNoClassDefFoundError()->GetClass());
}
// Clear exceptions caught in DexFile.defineClass.
ALWAYS_INLINE void FilterDexFileCaughtExceptions(Thread* self, ClassLinker* class_linker)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (MatchesDexFileCaughtExceptions(self->GetException(), class_linker)) {
self->ClearException();
}
}
} // namespace
// Finds the class in the boot class loader.
// If the class is found the method returns the resolved class. Otherwise it returns null.
bool ClassLinker::FindClassInBootClassLoaderClassPath(Thread* self,
const char* descriptor,
size_t hash,
/*out*/ ObjPtr<mirror::Class>* result) {
ClassPathEntry pair = FindInClassPath(descriptor, hash, boot_class_path_);
if (pair.second != nullptr) {
ObjPtr<mirror::Class> klass = LookupClass(self, descriptor, hash, nullptr);
if (klass != nullptr) {
*result = EnsureResolved(self, descriptor, klass);
} else {
*result = DefineClass(self,
descriptor,
hash,
ScopedNullHandle<mirror::ClassLoader>(),
*pair.first,
*pair.second);
}
if (*result == nullptr) {
CHECK(self->IsExceptionPending()) << descriptor;
FilterDexFileCaughtExceptions(self, this);
}
}
// The boot classloader is always a known lookup.
return true;
}
bool ClassLinker::FindClassInBaseDexClassLoaderClassPath(
ScopedObjectAccessAlreadyRunnable& soa,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader,
/*out*/ ObjPtr<mirror::Class>* result) {
DCHECK(IsPathOrDexClassLoader(soa, class_loader) ||
IsInMemoryDexClassLoader(soa, class_loader) ||
IsDelegateLastClassLoader(soa, class_loader))
<< "Unexpected class loader for descriptor " << descriptor;
const DexFile* dex_file = nullptr;
const dex::ClassDef* class_def = nullptr;
ObjPtr<mirror::Class> ret;
auto find_class_def = [&](const DexFile* cp_dex_file) REQUIRES_SHARED(Locks::mutator_lock_) {
const dex::ClassDef* cp_class_def = OatDexFile::FindClassDef(*cp_dex_file, descriptor, hash);
if (cp_class_def != nullptr) {
dex_file = cp_dex_file;
class_def = cp_class_def;
return false; // Found a class definition, stop visit.
}
return true; // Continue with the next DexFile.
};
VisitClassLoaderDexFiles(soa, class_loader, find_class_def);
if (class_def != nullptr) {
*result = DefineClass(soa.Self(), descriptor, hash, class_loader, *dex_file, *class_def);
if (UNLIKELY(*result == nullptr)) {
CHECK(soa.Self()->IsExceptionPending()) << descriptor;
FilterDexFileCaughtExceptions(soa.Self(), this);
} else {
DCHECK(!soa.Self()->IsExceptionPending());
}
}
// A BaseDexClassLoader is always a known lookup.
return true;
}
ObjPtr<mirror::Class> ClassLinker::FindClass(Thread* self,
const char* descriptor,
Handle<mirror::ClassLoader> class_loader) {
DCHECK_NE(*descriptor, '\0') << "descriptor is empty string";
DCHECK(self != nullptr);
self->AssertNoPendingException();
self->PoisonObjectPointers(); // For DefineClass, CreateArrayClass, etc...
if (descriptor[1] == '\0') {
// only the descriptors of primitive types should be 1 character long, also avoid class lookup
// for primitive classes that aren't backed by dex files.
return FindPrimitiveClass(descriptor[0]);
}
const size_t hash = ComputeModifiedUtf8Hash(descriptor);
// Find the class in the loaded classes table.
ObjPtr<mirror::Class> klass = LookupClass(self, descriptor, hash, class_loader.Get());
if (klass != nullptr) {
return EnsureResolved(self, descriptor, klass);
}
// Class is not yet loaded.
if (descriptor[0] != '[' && class_loader == nullptr) {
// Non-array class and the boot class loader, search the boot class path.
ClassPathEntry pair = FindInClassPath(descriptor, hash, boot_class_path_);
if (pair.second != nullptr) {
return DefineClass(self,
descriptor,
hash,
ScopedNullHandle<mirror::ClassLoader>(),
*pair.first,
*pair.second);
} else {
// The boot class loader is searched ahead of the application class loader, failures are
// expected and will be wrapped in a ClassNotFoundException. Use the pre-allocated error to
// trigger the chaining with a proper stack trace.
ObjPtr<mirror::Throwable> pre_allocated =
Runtime::Current()->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
return nullptr;
}
}
ObjPtr<mirror::Class> result_ptr;
bool descriptor_equals;
if (descriptor[0] == '[') {
result_ptr = CreateArrayClass(self, descriptor, hash, class_loader);
DCHECK_EQ(result_ptr == nullptr, self->IsExceptionPending());
DCHECK(result_ptr == nullptr || result_ptr->DescriptorEquals(descriptor));
descriptor_equals = true;
} else {
ScopedObjectAccessUnchecked soa(self);
bool known_hierarchy =
FindClassInBaseDexClassLoader(soa, self, descriptor, hash, class_loader, &result_ptr);
if (result_ptr != nullptr) {
// The chain was understood and we found the class. We still need to add the class to
// the class table to protect from racy programs that can try and redefine the path list
// which would change the Class<?> returned for subsequent evaluation of const-class.
DCHECK(known_hierarchy);
DCHECK(result_ptr->DescriptorEquals(descriptor));
descriptor_equals = true;
} else if (!self->IsExceptionPending()) {
// Either the chain wasn't understood or the class wasn't found.
// If there is a pending exception we didn't clear, it is a not a ClassNotFoundException and
// we should return it instead of silently clearing and retrying.
//
// If the chain was understood but we did not find the class, let the Java-side
// rediscover all this and throw the exception with the right stack trace. Note that
// the Java-side could still succeed for racy programs if another thread is actively
// modifying the class loader's path list.
// The runtime is not allowed to call into java from a runtime-thread so just abort.
if (self->IsRuntimeThread()) {
// Oops, we can't call into java so we can't run actual class-loader code.
// This is true for e.g. for the compiler (jit or aot).
ObjPtr<mirror::Throwable> pre_allocated =
Runtime::Current()->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
return nullptr;
}
// Inlined DescriptorToDot(descriptor) with extra validation.
//
// Throw NoClassDefFoundError early rather than potentially load a class only to fail
// the DescriptorEquals() check below and give a confusing error message. For example,
// when native code erroneously calls JNI GetFieldId() with signature "java/lang/String"
// instead of "Ljava/lang/String;", the message below using the "dot" names would be
// "class loader [...] returned class java.lang.String instead of java.lang.String".
size_t descriptor_length = strlen(descriptor);
if (UNLIKELY(descriptor[0] != 'L') ||
UNLIKELY(descriptor[descriptor_length - 1] != ';') ||
UNLIKELY(memchr(descriptor + 1, '.', descriptor_length - 2) != nullptr)) {
ThrowNoClassDefFoundError("Invalid descriptor: %s.", descriptor);
return nullptr;
}
std::string class_name_string(descriptor + 1, descriptor_length - 2);
std::replace(class_name_string.begin(), class_name_string.end(), '/', '.');
if (known_hierarchy &&
fast_class_not_found_exceptions_ &&
!Runtime::Current()->IsJavaDebuggable()) {
// For known hierarchy, we know that the class is going to throw an exception. If we aren't
// debuggable, optimize this path by throwing directly here without going back to Java
// language. This reduces how many ClassNotFoundExceptions happen.
self->ThrowNewExceptionF("Ljava/lang/ClassNotFoundException;",
"%s",
class_name_string.c_str());
} else {
ScopedLocalRef<jobject> class_loader_object(
soa.Env(), soa.AddLocalReference<jobject>(class_loader.Get()));
ScopedLocalRef<jobject> result(soa.Env(), nullptr);
{
ScopedThreadStateChange tsc(self, ThreadState::kNative);
ScopedLocalRef<jobject> class_name_object(
soa.Env(), soa.Env()->NewStringUTF(class_name_string.c_str()));
if (class_name_object.get() == nullptr) {
DCHECK(self->IsExceptionPending()); // OOME.
return nullptr;
}
CHECK(class_loader_object.get() != nullptr);
result.reset(soa.Env()->CallObjectMethod(class_loader_object.get(),
WellKnownClasses::java_lang_ClassLoader_loadClass,
class_name_object.get()));
}
if (result.get() == nullptr && !self->IsExceptionPending()) {
// broken loader - throw NPE to be compatible with Dalvik
ThrowNullPointerException(StringPrintf("ClassLoader.loadClass returned null for %s",
class_name_string.c_str()).c_str());
return nullptr;
}
result_ptr = soa.Decode<mirror::Class>(result.get());
// Check the name of the returned class.
descriptor_equals = (result_ptr != nullptr) && result_ptr->DescriptorEquals(descriptor);
}
} else {
DCHECK(!MatchesDexFileCaughtExceptions(self->GetException(), this));
}
}
if (self->IsExceptionPending()) {
// If the ClassLoader threw or array class allocation failed, pass that exception up.
// However, to comply with the RI behavior, first check if another thread succeeded.
result_ptr = LookupClass(self, descriptor, hash, class_loader.Get());
if (result_ptr != nullptr && !result_ptr->IsErroneous()) {
self->ClearException();
return EnsureResolved(self, descriptor, result_ptr);
}
return nullptr;
}
// Try to insert the class to the class table, checking for mismatch.
ObjPtr<mirror::Class> old;
{
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
ClassTable* const class_table = InsertClassTableForClassLoader(class_loader.Get());
old = class_table->Lookup(descriptor, hash);
if (old == nullptr) {
old = result_ptr; // For the comparison below, after releasing the lock.
if (descriptor_equals) {
class_table->InsertWithHash(result_ptr, hash);
WriteBarrier::ForEveryFieldWrite(class_loader.Get());
} // else throw below, after releasing the lock.
}
}
if (UNLIKELY(old != result_ptr)) {
// Return `old` (even if `!descriptor_equals`) to mimic the RI behavior for parallel
// capable class loaders. (All class loaders are considered parallel capable on Android.)
ObjPtr<mirror::Class> loader_class = class_loader->GetClass();
const char* loader_class_name =
loader_class->GetDexFile().StringByTypeIdx(loader_class->GetDexTypeIndex());
LOG(WARNING) << "Initiating class loader of type " << DescriptorToDot(loader_class_name)
<< " is not well-behaved; it returned a different Class for racing loadClass(\""
<< DescriptorToDot(descriptor) << "\").";
return EnsureResolved(self, descriptor, old);
}
if (UNLIKELY(!descriptor_equals)) {
std::string result_storage;
const char* result_name = result_ptr->GetDescriptor(&result_storage);
std::string loader_storage;
const char* loader_class_name = class_loader->GetClass()->GetDescriptor(&loader_storage);
ThrowNoClassDefFoundError(
"Initiating class loader of type %s returned class %s instead of %s.",
DescriptorToDot(loader_class_name).c_str(),
DescriptorToDot(result_name).c_str(),
DescriptorToDot(descriptor).c_str());
return nullptr;
}
// Success.
return result_ptr;
}
// Helper for maintaining DefineClass counting. We need to notify callbacks when we start/end a
// define-class and how many recursive DefineClasses we are at in order to allow for doing things
// like pausing class definition.
struct ScopedDefiningClass {
public:
explicit ScopedDefiningClass(Thread* self) REQUIRES_SHARED(Locks::mutator_lock_)
: self_(self), returned_(false) {
Locks::mutator_lock_->AssertSharedHeld(self_);
Runtime::Current()->GetRuntimeCallbacks()->BeginDefineClass();
self_->IncrDefineClassCount();
}
~ScopedDefiningClass() REQUIRES_SHARED(Locks::mutator_lock_) {
Locks::mutator_lock_->AssertSharedHeld(self_);
CHECK(returned_);
}
ObjPtr<mirror::Class> Finish(Handle<mirror::Class> h_klass)
REQUIRES_SHARED(Locks::mutator_lock_) {
CHECK(!returned_);
self_->DecrDefineClassCount();
Runtime::Current()->GetRuntimeCallbacks()->EndDefineClass();
Thread::PoisonObjectPointersIfDebug();
returned_ = true;
return h_klass.Get();
}
ObjPtr<mirror::Class> Finish(ObjPtr<mirror::Class> klass)
REQUIRES_SHARED(Locks::mutator_lock_) {
StackHandleScope<1> hs(self_);
Handle<mirror::Class> h_klass(hs.NewHandle(klass));
return Finish(h_klass);
}
ObjPtr<mirror::Class> Finish(nullptr_t np ATTRIBUTE_UNUSED)
REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedNullHandle<mirror::Class> snh;
return Finish(snh);
}
private:
Thread* self_;
bool returned_;
};
ObjPtr<mirror::Class> ClassLinker::DefineClass(Thread* self,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader,
const DexFile& dex_file,
const dex::ClassDef& dex_class_def) {
ScopedDefiningClass sdc(self);
StackHandleScope<3> hs(self);
metrics::AutoTimer timer{GetMetrics()->ClassLoadingTotalTime()};
auto klass = hs.NewHandle<mirror::Class>(nullptr);
// Load the class from the dex file.
if (UNLIKELY(!init_done_)) {
// finish up init of hand crafted class_roots_
if (strcmp(descriptor, "Ljava/lang/Object;") == 0) {
klass.Assign(GetClassRoot<mirror::Object>(this));
} else if (strcmp(descriptor, "Ljava/lang/Class;") == 0) {
klass.Assign(GetClassRoot<mirror::Class>(this));
} else if (strcmp(descriptor, "Ljava/lang/String;") == 0) {
klass.Assign(GetClassRoot<mirror::String>(this));
} else if (strcmp(descriptor, "Ljava/lang/ref/Reference;") == 0) {
klass.Assign(GetClassRoot<mirror::Reference>(this));
} else if (strcmp(descriptor, "Ljava/lang/DexCache;") == 0) {
klass.Assign(GetClassRoot<mirror::DexCache>(this));
} else if (strcmp(descriptor, "Ldalvik/system/ClassExt;") == 0) {
klass.Assign(GetClassRoot<mirror::ClassExt>(this));
}
}
// For AOT-compilation of an app, we may use only a public SDK to resolve symbols. If the SDK
// checks are configured (a non null SdkChecker) and the descriptor is not in the provided
// public class path then we prevent the definition of the class.
//
// NOTE that we only do the checks for the boot classpath APIs. Anything else, like the app
// classpath is not checked.
if (class_loader == nullptr &&
Runtime::Current()->IsAotCompiler() &&
DenyAccessBasedOnPublicSdk(descriptor)) {
ObjPtr<mirror::Throwable> pre_allocated =
Runtime::Current()->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
return sdc.Finish(nullptr);
}
// This is to prevent the calls to ClassLoad and ClassPrepare which can cause java/user-supplied
// code to be executed. We put it up here so we can avoid all the allocations associated with
// creating the class. This can happen with (eg) jit threads.
if (!self->CanLoadClasses()) {
// Make sure we don't try to load anything, potentially causing an infinite loop.
ObjPtr<mirror::Throwable> pre_allocated =
Runtime::Current()->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
return sdc.Finish(nullptr);
}
if (klass == nullptr) {
// Allocate a class with the status of not ready.
// Interface object should get the right size here. Regular class will
// figure out the right size later and be replaced with one of the right
// size when the class becomes resolved.
if (CanAllocClass()) {
klass.Assign(AllocClass(self, SizeOfClassWithoutEmbeddedTables(dex_file, dex_class_def)));
} else {
return sdc.Finish(nullptr);
}
}
if (UNLIKELY(klass == nullptr)) {
self->AssertPendingOOMException();
return sdc.Finish(nullptr);
}
// Get the real dex file. This will return the input if there aren't any callbacks or they do
// nothing.
DexFile const* new_dex_file = nullptr;
dex::ClassDef const* new_class_def = nullptr;
// TODO We should ideally figure out some way to move this after we get a lock on the klass so it
// will only be called once.
Runtime::Current()->GetRuntimeCallbacks()->ClassPreDefine(descriptor,
klass,
class_loader,
dex_file,
dex_class_def,
&new_dex_file,
&new_class_def);
// Check to see if an exception happened during runtime callbacks. Return if so.
if (self->IsExceptionPending()) {
return sdc.Finish(nullptr);
}
ObjPtr<mirror::DexCache> dex_cache = RegisterDexFile(*new_dex_file, class_loader.Get());
if (dex_cache == nullptr) {
self->AssertPendingException();
return sdc.Finish(nullptr);
}
klass->SetDexCache(dex_cache);
SetupClass(*new_dex_file, *new_class_def, klass, class_loader.Get());
// Mark the string class by setting its access flag.
if (UNLIKELY(!init_done_)) {
if (strcmp(descriptor, "Ljava/lang/String;") == 0) {
klass->SetStringClass();
}
}
ObjectLock<mirror::Class> lock(self, klass);
klass->SetClinitThreadId(self->GetTid());
// Make sure we have a valid empty iftable even if there are errors.
klass->SetIfTable(GetClassRoot<mirror::Object>(this)->GetIfTable());
// Add the newly loaded class to the loaded classes table.
ObjPtr<mirror::Class> existing = InsertClass(descriptor, klass.Get(), hash);
if (existing != nullptr) {
// We failed to insert because we raced with another thread. Calling EnsureResolved may cause
// this thread to block.
return sdc.Finish(EnsureResolved(self, descriptor, existing));
}
// Load the fields and other things after we are inserted in the table. This is so that we don't
// end up allocating unfree-able linear alloc resources and then lose the race condition. The
// other reason is that the field roots are only visited from the class table. So we need to be
// inserted before we allocate / fill in these fields.
LoadClass(self, *new_dex_file, *new_class_def, klass);
if (self->IsExceptionPending()) {
VLOG(class_linker) << self->GetException()->Dump();
// An exception occured during load, set status to erroneous while holding klass' lock in case
// notification is necessary.
if (!klass->IsErroneous()) {
mirror::Class::SetStatus(klass, ClassStatus::kErrorUnresolved, self);
}
return sdc.Finish(nullptr);
}
// Finish loading (if necessary) by finding parents
CHECK(!klass->IsLoaded());
if (!LoadSuperAndInterfaces(klass, *new_dex_file)) {
// Loading failed.
if (!klass->IsErroneous()) {
mirror::Class::SetStatus(klass, ClassStatus::kErrorUnresolved, self);
}
return sdc.Finish(nullptr);
}
CHECK(klass->IsLoaded());
// At this point the class is loaded. Publish a ClassLoad event.
// Note: this may be a temporary class. It is a listener's responsibility to handle this.
Runtime::Current()->GetRuntimeCallbacks()->ClassLoad(klass);
// Link the class (if necessary)
CHECK(!klass->IsResolved());
// TODO: Use fast jobjects?
auto interfaces = hs.NewHandle<mirror::ObjectArray<mirror::Class>>(nullptr);
MutableHandle<mirror::Class> h_new_class = hs.NewHandle<mirror::Class>(nullptr);
if (!LinkClass(self, descriptor, klass, interfaces, &h_new_class)) {
// Linking failed.
if (!klass->IsErroneous()) {
mirror::Class::SetStatus(klass, ClassStatus::kErrorUnresolved, self);
}
return sdc.Finish(nullptr);
}
self->AssertNoPendingException();
CHECK(h_new_class != nullptr) << descriptor;
CHECK(h_new_class->IsResolved()) << descriptor << " " << h_new_class->GetStatus();
// Instrumentation may have updated entrypoints for all methods of all
// classes. However it could not update methods of this class while we
// were loading it. Now the class is resolved, we can update entrypoints
// as required by instrumentation.
if (Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled()) {
// We must be in the kRunnable state to prevent instrumentation from
// suspending all threads to update entrypoints while we are doing it
// for this class.
DCHECK_EQ(self->GetState(), ThreadState::kRunnable);
Runtime::Current()->GetInstrumentation()->InstallStubsForClass(h_new_class.Get());
}
/*
* We send CLASS_PREPARE events to the debugger from here. The
* definition of "preparation" is creating the static fields for a
* class and initializing them to the standard default values, but not
* executing any code (that comes later, during "initialization").
*
* We did the static preparation in LinkClass.
*
* The class has been prepared and resolved but possibly not yet verified
* at this point.
*/
Runtime::Current()->GetRuntimeCallbacks()->ClassPrepare(klass, h_new_class);
// Notify native debugger of the new class and its layout.
jit::Jit::NewTypeLoadedIfUsingJit(h_new_class.Get());
return sdc.Finish(h_new_class);
}
uint32_t ClassLinker::SizeOfClassWithoutEmbeddedTables(const DexFile& dex_file,
const dex::ClassDef& dex_class_def) {
size_t num_ref = 0;
size_t num_8 = 0;
size_t num_16 = 0;
size_t num_32 = 0;
size_t num_64 = 0;
ClassAccessor accessor(dex_file, dex_class_def);
// We allow duplicate definitions of the same field in a class_data_item
// but ignore the repeated indexes here, b/21868015.
uint32_t last_field_idx = dex::kDexNoIndex;
for (const ClassAccessor::Field& field : accessor.GetStaticFields()) {
uint32_t field_idx = field.GetIndex();
// Ordering enforced by DexFileVerifier.
DCHECK(last_field_idx == dex::kDexNoIndex || last_field_idx <= field_idx);
if (UNLIKELY(field_idx == last_field_idx)) {
continue;
}
last_field_idx = field_idx;
const dex::FieldId& field_id = dex_file.GetFieldId(field_idx);
const char* descriptor = dex_file.GetFieldTypeDescriptor(field_id);
char c = descriptor[0];
switch (c) {
case 'L':
case '[':
num_ref++;
break;
case 'J':
case 'D':
num_64++;
break;
case 'I':
case 'F':
num_32++;
break;
case 'S':
case 'C':
num_16++;
break;
case 'B':
case 'Z':
num_8++;
break;
default:
LOG(FATAL) << "Unknown descriptor: " << c;
UNREACHABLE();
}
}
return mirror::Class::ComputeClassSize(false,
0,
num_8,
num_16,
num_32,
num_64,
num_ref,
image_pointer_size_);
}
// Special case to get oat code without overwriting a trampoline.
const void* ClassLinker::GetQuickOatCodeFor(ArtMethod* method) {
CHECK(method->IsInvokable()) << method->PrettyMethod();
if (method->IsProxyMethod()) {
return GetQuickProxyInvokeHandler();
}
const void* code = method->GetOatMethodQuickCode(GetImagePointerSize());
if (code != nullptr) {
return code;
}
jit::Jit* jit = Runtime::Current()->GetJit();
if (jit != nullptr) {
code = jit->GetCodeCache()->GetSavedEntryPointOfPreCompiledMethod(method);
if (code != nullptr) {
return code;
}
}
if (method->IsNative()) {
// No code and native? Use generic trampoline.
return GetQuickGenericJniStub();
}
if (interpreter::CanRuntimeUseNterp() && CanMethodUseNterp(method)) {
return interpreter::GetNterpEntryPoint();
}
return GetQuickToInterpreterBridge();
}
bool ClassLinker::ShouldUseInterpreterEntrypoint(ArtMethod* method, const void* quick_code) {
ScopedAssertNoThreadSuspension sants(__FUNCTION__);
if (UNLIKELY(method->IsNative() || method->IsProxyMethod())) {
return false;
}
if (quick_code == nullptr) {
return true;
}
Runtime* runtime = Runtime::Current();
instrumentation::Instrumentation* instr = runtime->GetInstrumentation();
if (instr->InterpretOnly()) {
return true;
}
if (runtime->GetClassLinker()->IsQuickToInterpreterBridge(quick_code)) {
// Doing this check avoids doing compiled/interpreter transitions.
return true;
}
if (Thread::Current()->IsForceInterpreter()) {
// Force the use of interpreter when it is required by the debugger.
return true;
}
if (Thread::Current()->IsAsyncExceptionPending()) {
// Force use of interpreter to handle async-exceptions
return true;
}
if (quick_code == GetQuickInstrumentationEntryPoint()) {
const void* instr_target = instr->GetCodeForInvoke(method);
DCHECK_NE(instr_target, GetQuickInstrumentationEntryPoint()) << method->PrettyMethod();
return ShouldUseInterpreterEntrypoint(method, instr_target);
}
if (runtime->IsJavaDebuggable()) {
// For simplicity, we ignore precompiled code and go to the interpreter
// assuming we don't already have jitted code.
// We could look at the oat file where `quick_code` is being defined,
// and check whether it's been compiled debuggable, but we decided to
// only rely on the JIT for debuggable apps.
jit::Jit* jit = Runtime::Current()->GetJit();
return (jit == nullptr) || !jit->GetCodeCache()->ContainsPc(quick_code);
}
if (runtime->IsNativeDebuggable()) {
DCHECK(runtime->UseJitCompilation() && runtime->GetJit()->JitAtFirstUse());
// If we are doing native debugging, ignore application's AOT code,
// since we want to JIT it (at first use) with extra stackmaps for native
// debugging. We keep however all AOT code from the boot image,
// since the JIT-at-first-use is blocking and would result in non-negligible
// startup performance impact.
return !runtime->GetHeap()->IsInBootImageOatFile(quick_code);
}
return false;
}
void ClassLinker::FixupStaticTrampolines(Thread* self, ObjPtr<mirror::Class> klass) {
ScopedAssertNoThreadSuspension sants(__FUNCTION__);
DCHECK(klass->IsVisiblyInitialized()) << klass->PrettyDescriptor();
size_t num_direct_methods = klass->NumDirectMethods();
if (num_direct_methods == 0) {
return; // No direct methods => no static methods.
}
if (UNLIKELY(klass->IsProxyClass())) {
return;
}
PointerSize pointer_size = image_pointer_size_;
if (std::any_of(klass->GetDirectMethods(pointer_size).begin(),
klass->GetDirectMethods(pointer_size).end(),
[](const ArtMethod& m) { return m.IsCriticalNative(); })) {
// Store registered @CriticalNative methods, if any, to JNI entrypoints.
// Direct methods are a contiguous chunk of memory, so use the ordering of the map.
ArtMethod* first_method = klass->GetDirectMethod(0u, pointer_size);
ArtMethod* last_method = klass->GetDirectMethod(num_direct_methods - 1u, pointer_size);
MutexLock lock(self, critical_native_code_with_clinit_check_lock_);
auto lb = critical_native_code_with_clinit_check_.lower_bound(first_method);
while (lb != critical_native_code_with_clinit_check_.end() && lb->first <= last_method) {
lb->first->SetEntryPointFromJni(lb->second);
lb = critical_native_code_with_clinit_check_.erase(lb);
}
}
Runtime* runtime = Runtime::Current();
if (!runtime->IsStarted()) {
if (runtime->IsAotCompiler() || runtime->GetHeap()->HasBootImageSpace()) {
return; // OAT file unavailable.
}
}
const DexFile& dex_file = klass->GetDexFile();
bool has_oat_class;
OatFile::OatClass oat_class = OatFile::FindOatClass(dex_file,
klass->GetDexClassDefIndex(),
&has_oat_class);
// Link the code of methods skipped by LinkCode.
for (size_t method_index = 0; method_index < num_direct_methods; ++method_index) {
ArtMethod* method = klass->GetDirectMethod(method_index, pointer_size);
if (!method->IsStatic()) {
// Only update static methods.
continue;
}
const void* quick_code = nullptr;
// In order:
// 1) Check if we have AOT Code.
// 2) Check if we have JIT Code.
// 3) Check if we can use Nterp.
if (has_oat_class) {
OatFile::OatMethod oat_method = oat_class.GetOatMethod(method_index);
quick_code = oat_method.GetQuickCode();
}
jit::Jit* jit = runtime->GetJit();
if (quick_code == nullptr && jit != nullptr) {
quick_code = jit->GetCodeCache()->GetSavedEntryPointOfPreCompiledMethod(method);
}
if (quick_code == nullptr &&
interpreter::CanRuntimeUseNterp() &&
CanMethodUseNterp(method)) {
quick_code = interpreter::GetNterpEntryPoint();
}
// Check whether the method is native, in which case it's generic JNI.
if (quick_code == nullptr && method->IsNative()) {
quick_code = GetQuickGenericJniStub();
} else if (ShouldUseInterpreterEntrypoint(method, quick_code)) {
// Use interpreter entry point.
if (IsQuickToInterpreterBridge(method->GetEntryPointFromQuickCompiledCode())) {
// If we have the trampoline or the bridge already, no need to update.
// This saves in not dirtying boot image memory.
continue;
}
quick_code = GetQuickToInterpreterBridge();
}
CHECK(quick_code != nullptr);
runtime->GetInstrumentation()->UpdateMethodsCode(method, quick_code);
}
// Ignore virtual methods on the iterator.
}
// Does anything needed to make sure that the compiler will not generate a direct invoke to this
// method. Should only be called on non-invokable methods.
inline void EnsureThrowsInvocationError(ClassLinker* class_linker, ArtMethod* method)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(method != nullptr);
DCHECK(!method->IsInvokable());
method->SetEntryPointFromQuickCompiledCodePtrSize(
class_linker->GetQuickToInterpreterBridgeTrampoline(),
class_linker->GetImagePointerSize());
}
static void LinkCode(ClassLinker* class_linker,
ArtMethod* method,
const OatFile::OatClass* oat_class,
uint32_t class_def_method_index) REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedAssertNoThreadSuspension sants(__FUNCTION__);
Runtime* const runtime = Runtime::Current();
if (runtime->IsAotCompiler()) {
// The following code only applies to a non-compiler runtime.
return;
}
// Method shouldn't have already been linked.
DCHECK(method->GetEntryPointFromQuickCompiledCode() == nullptr);
if (!method->IsInvokable()) {
EnsureThrowsInvocationError(class_linker, method);
return;
}
const void* quick_code = nullptr;
if (oat_class != nullptr) {
// Every kind of method should at least get an invoke stub from the oat_method.
// non-abstract methods also get their code pointers.
const OatFile::OatMethod oat_method = oat_class->GetOatMethod(class_def_method_index);
quick_code = oat_method.GetQuickCode();
}
bool enter_interpreter = class_linker->ShouldUseInterpreterEntrypoint(method, quick_code);
// Note: this mimics the logic in image_writer.cc that installs the resolution
// stub only if we have compiled code and the method needs a class initialization
// check.
if (quick_code == nullptr) {
if (method->IsNative()) {
method->SetEntryPointFromQuickCompiledCode(GetQuickGenericJniStub());
} else {
// Note we cannot use the nterp entrypoint because we do not know if the
// method will need the slow interpreter for lock verification. This will
// be updated in EnsureSkipAccessChecksMethods.
method->SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
}
} else if (enter_interpreter) {
method->SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
} else if (NeedsClinitCheckBeforeCall(method)) {
DCHECK(!method->GetDeclaringClass()->IsVisiblyInitialized()); // Actually ClassStatus::Idx.
// If we do have code but the method needs a class initialization check before calling
// that code, install the resolution stub that will perform the check.
// It will be replaced by the proper entry point by ClassLinker::FixupStaticTrampolines
// after initializing class (see ClassLinker::InitializeClass method).
method->SetEntryPointFromQuickCompiledCode(GetQuickResolutionStub());
} else {
method->SetEntryPointFromQuickCompiledCode(quick_code);
}
if (method->IsNative()) {
// Set up the dlsym lookup stub. Do not go through `UnregisterNative()`
// as the extra processing for @CriticalNative is not needed yet.
method->SetEntryPointFromJni(
method->IsCriticalNative() ? GetJniDlsymLookupCriticalStub() : GetJniDlsymLookupStub());
if (enter_interpreter || quick_code == nullptr) {
// We have a native method here without code. Then it should have the generic JNI
// trampoline as entrypoint.
// TODO: this doesn't handle all the cases where trampolines may be installed.
DCHECK(class_linker->IsQuickGenericJniStub(method->GetEntryPointFromQuickCompiledCode()));
}
}
}
void ClassLinker::SetupClass(const DexFile& dex_file,
const dex::ClassDef& dex_class_def,
Handle<mirror::Class> klass,
ObjPtr<mirror::ClassLoader> class_loader) {
CHECK(klass != nullptr);
CHECK(klass->GetDexCache() != nullptr);
CHECK_EQ(ClassStatus::kNotReady, klass->GetStatus());
const char* descriptor = dex_file.GetClassDescriptor(dex_class_def);
CHECK(descriptor != nullptr);
klass->SetClass(GetClassRoot<mirror::Class>(this));
uint32_t access_flags = dex_class_def.GetJavaAccessFlags();
CHECK_EQ(access_flags & ~kAccJavaFlagsMask, 0U);
klass->SetAccessFlagsDuringLinking(access_flags);
klass->SetClassLoader(class_loader);
DCHECK_EQ(klass->GetPrimitiveType(), Primitive::kPrimNot);
mirror::Class::SetStatus(klass, ClassStatus::kIdx, nullptr);
klass->SetDexClassDefIndex(dex_file.GetIndexForClassDef(dex_class_def));
klass->SetDexTypeIndex(dex_class_def.class_idx_);
}
LengthPrefixedArray<ArtField>* ClassLinker::AllocArtFieldArray(Thread* self,
LinearAlloc* allocator,
size_t length) {
if (length == 0) {
return nullptr;
}
// If the ArtField alignment changes, review all uses of LengthPrefixedArray<ArtField>.
static_assert(alignof(ArtField) == 4, "ArtField alignment is expected to be 4.");
size_t storage_size = LengthPrefixedArray<ArtField>::ComputeSize(length);
void* array_storage = allocator->Alloc(self, storage_size);
auto* ret = new(array_storage) LengthPrefixedArray<ArtField>(length);
CHECK(ret != nullptr);
std::uninitialized_fill_n(&ret->At(0), length, ArtField());
return ret;
}
LengthPrefixedArray<ArtMethod>* ClassLinker::AllocArtMethodArray(Thread* self,
LinearAlloc* allocator,
size_t length) {
if (length == 0) {
return nullptr;
}
const size_t method_alignment = ArtMethod::Alignment(image_pointer_size_);
const size_t method_size = ArtMethod::Size(image_pointer_size_);
const size_t storage_size =
LengthPrefixedArray<ArtMethod>::ComputeSize(length, method_size, method_alignment);
void* array_storage = allocator->Alloc(self, storage_size);
auto* ret = new (array_storage) LengthPrefixedArray<ArtMethod>(length);
CHECK(ret != nullptr);
for (size_t i = 0; i < length; ++i) {
new(reinterpret_cast<void*>(&ret->At(i, method_size, method_alignment))) ArtMethod;
}
return ret;
}
LinearAlloc* ClassLinker::GetAllocatorForClassLoader(ObjPtr<mirror::ClassLoader> class_loader) {
if (class_loader == nullptr) {
return Runtime::Current()->GetLinearAlloc();
}
LinearAlloc* allocator = class_loader->GetAllocator();
DCHECK(allocator != nullptr);
return allocator;
}
LinearAlloc* ClassLinker::GetOrCreateAllocatorForClassLoader(ObjPtr<mirror::ClassLoader> class_loader) {
if (class_loader == nullptr) {
return Runtime::Current()->GetLinearAlloc();
}
WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
LinearAlloc* allocator = class_loader->GetAllocator();
if (allocator == nullptr) {
RegisterClassLoader(class_loader);
allocator = class_loader->GetAllocator();
CHECK(allocator != nullptr);
}
return allocator;
}
void ClassLinker::LoadClass(Thread* self,
const DexFile& dex_file,
const dex::ClassDef& dex_class_def,
Handle<mirror::Class> klass) {
ClassAccessor accessor(dex_file,
dex_class_def,
/* parse_hiddenapi_class_data= */ klass->IsBootStrapClassLoaded());
if (!accessor.HasClassData()) {
return;
}
Runtime* const runtime = Runtime::Current();
{
// Note: We cannot have thread suspension until the field and method arrays are setup or else
// Class::VisitFieldRoots may miss some fields or methods.
ScopedAssertNoThreadSuspension nts(__FUNCTION__);
// Load static fields.
// We allow duplicate definitions of the same field in a class_data_item
// but ignore the repeated indexes here, b/21868015.
LinearAlloc* const allocator = GetAllocatorForClassLoader(klass->GetClassLoader());
LengthPrefixedArray<ArtField>* sfields = AllocArtFieldArray(self,
allocator,
accessor.NumStaticFields());
LengthPrefixedArray<ArtField>* ifields = AllocArtFieldArray(self,
allocator,
accessor.NumInstanceFields());
size_t num_sfields = 0u;
size_t num_ifields = 0u;
uint32_t last_static_field_idx = 0u;
uint32_t last_instance_field_idx = 0u;
// Methods
bool has_oat_class = false;
const OatFile::OatClass oat_class = (runtime->IsStarted() && !runtime->IsAotCompiler())
? OatFile::FindOatClass(dex_file, klass->GetDexClassDefIndex(), &has_oat_class)
: OatFile::OatClass::Invalid();
const OatFile::OatClass* oat_class_ptr = has_oat_class ? &oat_class : nullptr;
klass->SetMethodsPtr(
AllocArtMethodArray(self, allocator, accessor.NumMethods()),
accessor.NumDirectMethods(),
accessor.NumVirtualMethods());
size_t class_def_method_index = 0;
uint32_t last_dex_method_index = dex::kDexNoIndex;
size_t last_class_def_method_index = 0;
uint16_t hotness_threshold = runtime->GetJITOptions()->GetWarmupThreshold();
// Use the visitor since the ranged based loops are bit slower from seeking. Seeking to the
// methods needs to decode all of the fields.
accessor.VisitFieldsAndMethods([&](
const ClassAccessor::Field& field) REQUIRES_SHARED(Locks::mutator_lock_) {
uint32_t field_idx = field.GetIndex();
DCHECK_GE(field_idx, last_static_field_idx); // Ordering enforced by DexFileVerifier.
if (num_sfields == 0 || LIKELY(field_idx > last_static_field_idx)) {
LoadField(field, klass, &sfields->At(num_sfields));
++num_sfields;
last_static_field_idx = field_idx;
}
}, [&](const ClassAccessor::Field& field) REQUIRES_SHARED(Locks::mutator_lock_) {
uint32_t field_idx = field.GetIndex();
DCHECK_GE(field_idx, last_instance_field_idx); // Ordering enforced by DexFileVerifier.
if (num_ifields == 0 || LIKELY(field_idx > last_instance_field_idx)) {
LoadField(field, klass, &ifields->At(num_ifields));
++num_ifields;
last_instance_field_idx = field_idx;
}
}, [&](const ClassAccessor::Method& method) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtMethod* art_method = klass->GetDirectMethodUnchecked(class_def_method_index,
image_pointer_size_);
LoadMethod(dex_file, method, klass, art_method);
LinkCode(this, art_method, oat_class_ptr, class_def_method_index);
uint32_t it_method_index = method.GetIndex();
if (last_dex_method_index == it_method_index) {
// duplicate case
art_method->SetMethodIndex(last_class_def_method_index);
} else {
art_method->SetMethodIndex(class_def_method_index);
last_dex_method_index = it_method_index;
last_class_def_method_index = class_def_method_index;
}
art_method->ResetCounter(hotness_threshold);
++class_def_method_index;
}, [&](const ClassAccessor::Method& method) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtMethod* art_method = klass->GetVirtualMethodUnchecked(
class_def_method_index - accessor.NumDirectMethods(),
image_pointer_size_);
art_method->ResetCounter(hotness_threshold);
LoadMethod(dex_file, method, klass, art_method);
LinkCode(this, art_method, oat_class_ptr, class_def_method_index);
++class_def_method_index;
});
if (UNLIKELY(num_ifields + num_sfields != accessor.NumFields())) {
LOG(WARNING) << "Duplicate fields in class " << klass->PrettyDescriptor()
<< " (unique static fields: " << num_sfields << "/" << accessor.NumStaticFields()
<< ", unique instance fields: " << num_ifields << "/" << accessor.NumInstanceFields()
<< ")";
// NOTE: Not shrinking the over-allocated sfields/ifields, just setting size.
if (sfields != nullptr) {
sfields->SetSize(num_sfields);
}
if (ifields != nullptr) {
ifields->SetSize(num_ifields);
}
}
// Set the field arrays.
klass->SetSFieldsPtr(sfields);
DCHECK_EQ(klass->NumStaticFields(), num_sfields);
klass->SetIFieldsPtr(ifields);
DCHECK_EQ(klass->NumInstanceFields(), num_ifields);
}
// Ensure that the card is marked so that remembered sets pick up native roots.
WriteBarrier::ForEveryFieldWrite(klass.Get());
self->AllowThreadSuspension();
}
void ClassLinker::LoadField(const ClassAccessor::Field& field,
Handle<mirror::Class> klass,
ArtField* dst) {
const uint32_t field_idx = field.GetIndex();
dst->SetDexFieldIndex(field_idx);
dst->SetDeclaringClass(klass.Get());
// Get access flags from the DexFile and set hiddenapi runtime access flags.
dst->SetAccessFlags(field.GetAccessFlags() | hiddenapi::CreateRuntimeFlags(field));
}
void ClassLinker::LoadMethod(const DexFile& dex_file,
const ClassAccessor::Method& method,
Handle<mirror::Class> klass,
ArtMethod* dst) {
const uint32_t dex_method_idx = method.GetIndex();
const dex::MethodId& method_id = dex_file.GetMethodId(dex_method_idx);
const char* method_name = dex_file.StringDataByIdx(method_id.name_idx_);
ScopedAssertNoThreadSuspension ants("LoadMethod");
dst->SetDexMethodIndex(dex_method_idx);
dst->SetDeclaringClass(klass.Get());
// Get access flags from the DexFile and set hiddenapi runtime access flags.
uint32_t access_flags = method.GetAccessFlags() | hiddenapi::CreateRuntimeFlags(method);
if (UNLIKELY(strcmp("finalize", method_name) == 0)) {
// Set finalizable flag on declaring class.
if (strcmp("V", dex_file.GetShorty(method_id.proto_idx_)) == 0) {
// Void return type.
if (klass->GetClassLoader() != nullptr) { // All non-boot finalizer methods are flagged.
klass->SetFinalizable();
} else {
std::string temp;
const char* klass_descriptor = klass->GetDescriptor(&temp);
// The Enum class declares a "final" finalize() method to prevent subclasses from
// introducing a finalizer. We don't want to set the finalizable flag for Enum or its
// subclasses, so we exclude it here.
// We also want to avoid setting the flag on Object, where we know that finalize() is
// empty.
if (strcmp(klass_descriptor, "Ljava/lang/Object;") != 0 &&
strcmp(klass_descriptor, "Ljava/lang/Enum;") != 0) {
klass->SetFinalizable();
}
}
}
} else if (method_name[0] == '<') {
// Fix broken access flags for initializers. Bug 11157540.
bool is_init = (strcmp("<init>", method_name) == 0);
bool is_clinit = !is_init && (strcmp("<clinit>", method_name) == 0);
if (UNLIKELY(!is_init && !is_clinit)) {
LOG(WARNING) << "Unexpected '<' at start of method name " << method_name;
} else {
if (UNLIKELY((access_flags & kAccConstructor) == 0)) {
LOG(WARNING) << method_name << " didn't have expected constructor access flag in class "
<< klass->PrettyDescriptor() << " in dex file " << dex_file.GetLocation();
access_flags |= kAccConstructor;
}
}
}
if (UNLIKELY((access_flags & kAccNative) != 0u)) {
// Check if the native method is annotated with @FastNative or @CriticalNative.
access_flags |= annotations::GetNativeMethodAnnotationAccessFlags(
dex_file, dst->GetClassDef(), dex_method_idx);
}
dst->SetAccessFlags(access_flags);
// Must be done after SetAccessFlags since IsAbstract depends on it.
if (klass->IsInterface() && dst->IsAbstract()) {
dst->CalculateAndSetImtIndex();
}
if (dst->HasCodeItem()) {
DCHECK_NE(method.GetCodeItemOffset(), 0u);
if (Runtime::Current()->IsAotCompiler()) {
dst->SetDataPtrSize(reinterpret_cast32<void*>(method.GetCodeItemOffset()), image_pointer_size_);
} else {
dst->SetCodeItem(dst->GetDexFile()->GetCodeItem(method.GetCodeItemOffset()));
}
} else {
dst->SetDataPtrSize(nullptr, image_pointer_size_);
DCHECK_EQ(method.GetCodeItemOffset(), 0u);
}
// Set optimization flags related to the shorty.
uint32_t shorty_length;
const char* shorty = dst->GetShorty(&shorty_length);
bool all_parameters_are_reference = true;
bool all_parameters_are_reference_or_int = true;
bool return_type_is_fp = (shorty[0] == 'F' || shorty[0] == 'D');
for (size_t i = 1; i < shorty_length; ++i) {
if (shorty[i] != 'L') {
all_parameters_are_reference = false;
if (shorty[i] == 'F' || shorty[i] == 'D' || shorty[i] == 'J') {
all_parameters_are_reference_or_int = false;
break;
}
}
}
if (!dst->IsNative() && all_parameters_are_reference) {
dst->SetNterpEntryPointFastPathFlag();
}
if (!return_type_is_fp && all_parameters_are_reference_or_int) {
dst->SetNterpInvokeFastPathFlag();
}
}
void ClassLinker::AppendToBootClassPath(Thread* self, const DexFile* dex_file) {
ObjPtr<mirror::DexCache> dex_cache =
AllocAndInitializeDexCache(self, *dex_file, /* class_loader= */ nullptr);
CHECK(dex_cache != nullptr) << "Failed to allocate dex cache for " << dex_file->GetLocation();
AppendToBootClassPath(dex_file, dex_cache);
}
void ClassLinker::AppendToBootClassPath(const DexFile* dex_file,
ObjPtr<mirror::DexCache> dex_cache) {
CHECK(dex_file != nullptr);
CHECK(dex_cache != nullptr) << dex_file->GetLocation();
boot_class_path_.push_back(dex_file);
WriterMutexLock mu(Thread::Current(), *Locks::dex_lock_);
RegisterDexFileLocked(*dex_file, dex_cache, /* class_loader= */ nullptr);
}
void ClassLinker::RegisterDexFileLocked(const DexFile& dex_file,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader) {
Thread* const self = Thread::Current();
Locks::dex_lock_->AssertExclusiveHeld(self);
CHECK(dex_cache != nullptr) << dex_file.GetLocation();
CHECK_EQ(dex_cache->GetDexFile(), &dex_file) << dex_file.GetLocation();
// For app images, the dex cache location may be a suffix of the dex file location since the
// dex file location is an absolute path.
const std::string dex_cache_location = dex_cache->GetLocation()->ToModifiedUtf8();
const size_t dex_cache_length = dex_cache_location.length();
CHECK_GT(dex_cache_length, 0u) << dex_file.GetLocation();
std::string dex_file_location = dex_file.GetLocation();
// The following paths checks don't work on preopt when using boot dex files, where the dex
// cache location is the one on device, and the dex_file's location is the one on host.
if (!(Runtime::Current()->IsAotCompiler() && class_loader == nullptr && !kIsTargetBuild)) {
CHECK_GE(dex_file_location.length(), dex_cache_length)
<< dex_cache_location << " " << dex_file.GetLocation();
const std::string dex_file_suffix = dex_file_location.substr(
dex_file_location.length() - dex_cache_length,
dex_cache_length);
// Example dex_cache location is SettingsProvider.apk and
// dex file location is /system/priv-app/SettingsProvider/SettingsProvider.apk
CHECK_EQ(dex_cache_location, dex_file_suffix);
}
const OatFile* oat_file =
(dex_file.GetOatDexFile() != nullptr) ? dex_file.GetOatDexFile()->GetOatFile() : nullptr;
// Clean up pass to remove null dex caches; null dex caches can occur due to class unloading
// and we are lazily removing null entries. Also check if we need to initialize OatFile data
// (.data.bimg.rel.ro and .bss sections) needed for code execution.
bool initialize_oat_file_data = (oat_file != nullptr) && oat_file->IsExecutable();
JavaVMExt* const vm = self->GetJniEnv()->GetVm();
for (auto it = dex_caches_.begin(); it != dex_caches_.end(); ) {
const DexCacheData& data = it->second;
if (self->IsJWeakCleared(data.weak_root)) {
vm->DeleteWeakGlobalRef(self, data.weak_root);
it = dex_caches_.erase(it);
} else {
if (initialize_oat_file_data &&
it->first->GetOatDexFile() != nullptr &&
it->first->GetOatDexFile()->GetOatFile() == oat_file) {
initialize_oat_file_data = false; // Already initialized.
}
++it;
}
}
if (initialize_oat_file_data) {
oat_file->InitializeRelocations();
}
// Let hiddenapi assign a domain to the newly registered dex file.
hiddenapi::InitializeDexFileDomain(dex_file, class_loader);
jweak dex_cache_jweak = vm->AddWeakGlobalRef(self, dex_cache);
DexCacheData data;
data.weak_root = dex_cache_jweak;
data.class_table = ClassTableForClassLoader(class_loader);
AddNativeDebugInfoForDex(self, &dex_file);
DCHECK(data.class_table != nullptr);
// Make sure to hold the dex cache live in the class table. This case happens for the boot class
// path dex caches without an image.
data.class_table->InsertStrongRoot(dex_cache);
// Make sure that the dex cache holds the classloader live.
dex_cache->SetClassLoader(class_loader);
if (class_loader != nullptr) {
// Since we added a strong root to the class table, do the write barrier as required for
// remembered sets and generational GCs.
WriteBarrier::ForEveryFieldWrite(class_loader);
}
bool inserted = dex_caches_.emplace(&dex_file, std::move(data)).second;
CHECK(inserted);
}
ObjPtr<mirror::DexCache> ClassLinker::DecodeDexCacheLocked(Thread* self, const DexCacheData* data) {
return data != nullptr
? ObjPtr<mirror::DexCache>::DownCast(self->DecodeJObject(data->weak_root))
: nullptr;
}
bool ClassLinker::IsSameClassLoader(
ObjPtr<mirror::DexCache> dex_cache,
const DexCacheData* data,
ObjPtr<mirror::ClassLoader> class_loader) {
CHECK(data != nullptr);
DCHECK_EQ(FindDexCacheDataLocked(*dex_cache->GetDexFile()), data);
return data->class_table == ClassTableForClassLoader(class_loader);
}
void ClassLinker::RegisterExistingDexCache(ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader) {
SCOPED_TRACE << __FUNCTION__ << " " << dex_cache->GetDexFile()->GetLocation();
Thread* self = Thread::Current();
StackHandleScope<2> hs(self);
Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(dex_cache));
Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(class_loader));
const DexFile* dex_file = dex_cache->GetDexFile();
DCHECK(dex_file != nullptr) << "Attempt to register uninitialized dex_cache object!";
if (kIsDebugBuild) {
ReaderMutexLock mu(self, *Locks::dex_lock_);
const DexCacheData* old_data = FindDexCacheDataLocked(*dex_file);
ObjPtr<mirror::DexCache> old_dex_cache = DecodeDexCacheLocked(self, old_data);
DCHECK(old_dex_cache.IsNull()) << "Attempt to manually register a dex cache thats already "
<< "been registered on dex file " << dex_file->GetLocation();
}
ClassTable* table;
{
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
table = InsertClassTableForClassLoader(h_class_loader.Get());
}
// Avoid a deadlock between a garbage collecting thread running a checkpoint,
// a thread holding the dex lock and blocking on a condition variable regarding
// weak references access, and a thread blocking on the dex lock.
gc::ScopedGCCriticalSection gcs(self, gc::kGcCauseClassLinker, gc::kCollectorTypeClassLinker);
WriterMutexLock mu(self, *Locks::dex_lock_);
RegisterDexFileLocked(*dex_file, h_dex_cache.Get(), h_class_loader.Get());
table->InsertStrongRoot(h_dex_cache.Get());
if (h_class_loader.Get() != nullptr) {
// Since we added a strong root to the class table, do the write barrier as required for
// remembered sets and generational GCs.
WriteBarrier::ForEveryFieldWrite(h_class_loader.Get());
}
}
static void ThrowDexFileAlreadyRegisteredError(Thread* self, const DexFile& dex_file)
REQUIRES_SHARED(Locks::mutator_lock_) {
self->ThrowNewExceptionF("Ljava/lang/InternalError;",
"Attempt to register dex file %s with multiple class loaders",
dex_file.GetLocation().c_str());
}
ObjPtr<mirror::DexCache> ClassLinker::RegisterDexFile(const DexFile& dex_file,
ObjPtr<mirror::ClassLoader> class_loader) {
Thread* self = Thread::Current();
ObjPtr<mirror::DexCache> old_dex_cache;
bool registered_with_another_class_loader = false;
{
ReaderMutexLock mu(self, *Locks::dex_lock_);
const DexCacheData* old_data = FindDexCacheDataLocked(dex_file);
old_dex_cache = DecodeDexCacheLocked(self, old_data);
if (old_dex_cache != nullptr) {
if (IsSameClassLoader(old_dex_cache, old_data, class_loader)) {
return old_dex_cache;
} else {
// TODO This is not very clean looking. Should maybe try to make a way to request exceptions
// be thrown when it's safe to do so to simplify this.
registered_with_another_class_loader = true;
}
}
}
// We need to have released the dex_lock_ to allocate safely.
if (registered_with_another_class_loader) {
ThrowDexFileAlreadyRegisteredError(self, dex_file);
return nullptr;
}
SCOPED_TRACE << __FUNCTION__ << " " << dex_file.GetLocation();
LinearAlloc* const linear_alloc = GetOrCreateAllocatorForClassLoader(class_loader);
DCHECK(linear_alloc != nullptr);
ClassTable* table;
{
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
table = InsertClassTableForClassLoader(class_loader);
}
// Don't alloc while holding the lock, since allocation may need to
// suspend all threads and another thread may need the dex_lock_ to
// get to a suspend point.
StackHandleScope<3> hs(self);
Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(class_loader));
Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(AllocDexCache(self, dex_file)));
{
// Avoid a deadlock between a garbage collecting thread running a checkpoint,
// a thread holding the dex lock and blocking on a condition variable regarding
// weak references access, and a thread blocking on the dex lock.
gc::ScopedGCCriticalSection gcs(self, gc::kGcCauseClassLinker, gc::kCollectorTypeClassLinker);
WriterMutexLock mu(self, *Locks::dex_lock_);
const DexCacheData* old_data = FindDexCacheDataLocked(dex_file);
old_dex_cache = DecodeDexCacheLocked(self, old_data);
if (old_dex_cache == nullptr && h_dex_cache != nullptr) {
// Do Initialize while holding dex lock to make sure two threads don't call it
// at the same time with the same dex cache. Since the .bss is shared this can cause failing
// DCHECK that the arrays are null.
h_dex_cache->Initialize(&dex_file, h_class_loader.Get());
RegisterDexFileLocked(dex_file, h_dex_cache.Get(), h_class_loader.Get());
}
if (old_dex_cache != nullptr) {
// Another thread managed to initialize the dex cache faster, so use that DexCache.
// If this thread encountered OOME, ignore it.
DCHECK_EQ(h_dex_cache == nullptr, self->IsExceptionPending());
self->ClearException();
// We cannot call EnsureSameClassLoader() or allocate an exception while holding the
// dex_lock_.
if (IsSameClassLoader(old_dex_cache, old_data, h_class_loader.Get())) {
return old_dex_cache;
} else {
registered_with_another_class_loader = true;
}
}
}
if (registered_with_another_class_loader) {
ThrowDexFileAlreadyRegisteredError(self, dex_file);
return nullptr;
}
if (h_dex_cache == nullptr) {
self->AssertPendingOOMException();
return nullptr;
}
table->InsertStrongRoot(h_dex_cache.Get());
if (h_class_loader.Get() != nullptr) {
// Since we added a strong root to the class table, do the write barrier as required for
// remembered sets and generational GCs.
WriteBarrier::ForEveryFieldWrite(h_class_loader.Get());
}
VLOG(class_linker) << "Registered dex file " << dex_file.GetLocation();
PaletteNotifyDexFileLoaded(dex_file.GetLocation().c_str());
return h_dex_cache.Get();
}
bool ClassLinker::IsDexFileRegistered(Thread* self, const DexFile& dex_file) {
ReaderMutexLock mu(self, *Locks::dex_lock_);
return DecodeDexCacheLocked(self, FindDexCacheDataLocked(dex_file)) != nullptr;
}
ObjPtr<mirror::DexCache> ClassLinker::FindDexCache(Thread* self, const DexFile& dex_file) {
ReaderMutexLock mu(self, *Locks::dex_lock_);
const DexCacheData* dex_cache_data = FindDexCacheDataLocked(dex_file);
ObjPtr<mirror::DexCache> dex_cache = DecodeDexCacheLocked(self, dex_cache_data);
if (dex_cache != nullptr) {
return dex_cache;
}
// Failure, dump diagnostic and abort.
for (const auto& entry : dex_caches_) {
const DexCacheData& data = entry.second;
if (DecodeDexCacheLocked(self, &data) != nullptr) {
LOG(FATAL_WITHOUT_ABORT) << "Registered dex file " << entry.first->GetLocation();
}
}
LOG(FATAL) << "Failed to find DexCache for DexFile " << dex_file.GetLocation()
<< " " << &dex_file;
UNREACHABLE();
}
ObjPtr<mirror::DexCache> ClassLinker::FindDexCache(Thread* self, const OatDexFile& oat_dex_file) {
ReaderMutexLock mu(self, *Locks::dex_lock_);
const DexCacheData* dex_cache_data = FindDexCacheDataLocked(oat_dex_file);
ObjPtr<mirror::DexCache> dex_cache = DecodeDexCacheLocked(self, dex_cache_data);
if (dex_cache != nullptr) {
return dex_cache;
}
// Failure, dump diagnostic and abort.
for (const auto& entry : dex_caches_) {
const DexCacheData& data = entry.second;
if (DecodeDexCacheLocked(self, &data) != nullptr) {
LOG(FATAL_WITHOUT_ABORT) << "Registered dex file " << entry.first->GetLocation();
}
}
LOG(FATAL) << "Failed to find DexCache for OatDexFile " << oat_dex_file.GetDexFileLocation()
<< " " << &oat_dex_file;
UNREACHABLE();
}
ClassTable* ClassLinker::FindClassTable(Thread* self, ObjPtr<mirror::DexCache> dex_cache) {
const DexFile* dex_file = dex_cache->GetDexFile();
DCHECK(dex_file != nullptr);
ReaderMutexLock mu(self, *Locks::dex_lock_);
auto it = dex_caches_.find(dex_file);
if (it != dex_caches_.end()) {
const DexCacheData& data = it->second;
ObjPtr<mirror::DexCache> registered_dex_cache = DecodeDexCacheLocked(self, &data);
if (registered_dex_cache != nullptr) {
CHECK_EQ(registered_dex_cache, dex_cache) << dex_file->GetLocation();
return data.class_table;
}
}
return nullptr;
}
const ClassLinker::DexCacheData* ClassLinker::FindDexCacheDataLocked(
const OatDexFile& oat_dex_file) {
auto it = std::find_if(dex_caches_.begin(), dex_caches_.end(), [&](const auto& entry) {
return entry.first->GetOatDexFile() == &oat_dex_file;
});
return it != dex_caches_.end() ? &it->second : nullptr;
}
const ClassLinker::DexCacheData* ClassLinker::FindDexCacheDataLocked(const DexFile& dex_file) {
auto it = dex_caches_.find(&dex_file);
return it != dex_caches_.end() ? &it->second : nullptr;
}
void ClassLinker::CreatePrimitiveClass(Thread* self,
Primitive::Type type,
ClassRoot primitive_root) {
ObjPtr<mirror::Class> primitive_class =
AllocClass(self, mirror::Class::PrimitiveClassSize(image_pointer_size_));
CHECK(primitive_class != nullptr) << "OOM for primitive class " << type;
// Do not hold lock on the primitive class object, the initialization of
// primitive classes is done while the process is still single threaded.
primitive_class->SetAccessFlagsDuringLinking(kAccPublic | kAccFinal | kAccAbstract);
primitive_class->SetPrimitiveType(type);
primitive_class->SetIfTable(GetClassRoot<mirror::Object>(this)->GetIfTable());
DCHECK_EQ(primitive_class->NumMethods(), 0u);
// Primitive classes are initialized during single threaded startup, so visibly initialized.
primitive_class->SetStatusForPrimitiveOrArray(ClassStatus::kVisiblyInitialized);
const char* descriptor = Primitive::Descriptor(type);
ObjPtr<mirror::Class> existing = InsertClass(descriptor,
primitive_class,
ComputeModifiedUtf8Hash(descriptor));
CHECK(existing == nullptr) << "InitPrimitiveClass(" << type << ") failed";
SetClassRoot(primitive_root, primitive_class);
}
inline ObjPtr<mirror::IfTable> ClassLinker::GetArrayIfTable() {
return GetClassRoot<mirror::ObjectArray<mirror::Object>>(this)->GetIfTable();
}
// Create an array class (i.e. the class object for the array, not the
// array itself). "descriptor" looks like "[C" or "[[[[B" or
// "[Ljava/lang/String;".
//
// If "descriptor" refers to an array of primitives, look up the
// primitive type's internally-generated class object.
//
// "class_loader" is the class loader of the class that's referring to
// us. It's used to ensure that we're looking for the element type in
// the right context. It does NOT become the class loader for the
// array class; that always comes from the base element class.
//
// Returns null with an exception raised on failure.
ObjPtr<mirror::Class> ClassLinker::CreateArrayClass(Thread* self,
const char* descriptor,
size_t hash,
Handle<mirror::ClassLoader> class_loader) {
// Identify the underlying component type
CHECK_EQ('[', descriptor[0]);
StackHandleScope<2> hs(self);
// This is to prevent the calls to ClassLoad and ClassPrepare which can cause java/user-supplied
// code to be executed. We put it up here so we can avoid all the allocations associated with
// creating the class. This can happen with (eg) jit threads.
if (!self->CanLoadClasses()) {
// Make sure we don't try to load anything, potentially causing an infinite loop.
ObjPtr<mirror::Throwable> pre_allocated =
Runtime::Current()->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
return nullptr;
}
MutableHandle<mirror::Class> component_type(hs.NewHandle(FindClass(self, descriptor + 1,
class_loader)));
if (component_type == nullptr) {
DCHECK(self->IsExceptionPending());
// We need to accept erroneous classes as component types.
const size_t component_hash = ComputeModifiedUtf8Hash(descriptor + 1);
component_type.Assign(LookupClass(self, descriptor + 1, component_hash, class_loader.Get()));
if (component_type == nullptr) {
DCHECK(self->IsExceptionPending());
return nullptr;
} else {
self->ClearException();
}
}
if (UNLIKELY(component_type->IsPrimitiveVoid())) {
ThrowNoClassDefFoundError("Attempt to create array of void primitive type");
return nullptr;
}
// See if the component type is already loaded. Array classes are
// always associated with the class loader of their underlying
// element type -- an array of Strings goes with the loader for
// java/lang/String -- so we need to look for it there. (The
// caller should have checked for the existence of the class
// before calling here, but they did so with *their* class loader,
// not the component type's loader.)
//
// If we find it, the caller adds "loader" to the class' initiating
// loader list, which should prevent us from going through this again.
//
// This call is unnecessary if "loader" and "component_type->GetClassLoader()"
// are the same, because our caller (FindClass) just did the
// lookup. (Even if we get this wrong we still have correct behavior,
// because we effectively do this lookup again when we add the new
// class to the hash table --- necessary because of possible races with
// other threads.)
if (class_loader.Get() != component_type->GetClassLoader()) {
ObjPtr<mirror::Class> new_class =
LookupClass(self, descriptor, hash, component_type->GetClassLoader());
if (new_class != nullptr) {
return new_class;
}
}
// Core array classes, i.e. Object[], Class[], String[] and primitive
// arrays, have special initialization and they should be found above.
DCHECK(!component_type->IsObjectClass() ||
// Guard from false positives for errors before setting superclass.
component_type->IsErroneousUnresolved());
DCHECK(!component_type->IsStringClass());
DCHECK(!component_type->IsClassClass());
DCHECK(!component_type->IsPrimitive());
// Fill out the fields in the Class.
//
// It is possible to execute some methods against arrays, because
// all arrays are subclasses of java_lang_Object_, so we need to set
// up a vtable. We can just point at the one in java_lang_Object_.
//
// Array classes are simple enough that we don't need to do a full
// link step.
size_t array_class_size = mirror::Array::ClassSize(image_pointer_size_);
auto visitor = [this, array_class_size, component_type](ObjPtr<mirror::Object> obj,
size_t usable_size)
REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedAssertNoNewTransactionRecords sanntr("CreateArrayClass");
mirror::Class::InitializeClassVisitor init_class(array_class_size);
init_class(obj, usable_size);
ObjPtr<mirror::Class> klass = ObjPtr<mirror::Class>::DownCast(obj);
klass->SetComponentType(component_type.Get());
// Do not hold lock for initialization, the fence issued after the visitor
// returns ensures memory visibility together with the implicit consume
// semantics (for all supported architectures) for any thread that loads
// the array class reference from any memory locations afterwards.
FinishArrayClassSetup(klass);
};
auto new_class = hs.NewHandle<mirror::Class>(
AllocClass(self, GetClassRoot<mirror::Class>(this), array_class_size, visitor));
if (new_class == nullptr) {
self->AssertPendingOOMException();
return nullptr;
}
ObjPtr<mirror::Class> existing = InsertClass(descriptor, new_class.Get(), hash);
if (existing == nullptr) {
// We postpone ClassLoad and ClassPrepare events to this point in time to avoid
// duplicate events in case of races. Array classes don't really follow dedicated
// load and prepare, anyways.
Runtime::Current()->GetRuntimeCallbacks()->ClassLoad(new_class);
Runtime::Current()->GetRuntimeCallbacks()->ClassPrepare(new_class, new_class);
jit::Jit::NewTypeLoadedIfUsingJit(new_class.Get());
return new_class.Get();
}
// Another thread must have loaded the class after we
// started but before we finished. Abandon what we've
// done.
//
// (Yes, this happens.)
return existing;
}
ObjPtr<mirror::Class> ClassLinker::LookupPrimitiveClass(char type) {
ClassRoot class_root;
switch (type) {
case 'B': class_root = ClassRoot::kPrimitiveByte; break;
case 'C': class_root = ClassRoot::kPrimitiveChar; break;
case 'D': class_root = ClassRoot::kPrimitiveDouble; break;
case 'F': class_root = ClassRoot::kPrimitiveFloat; break;
case 'I': class_root = ClassRoot::kPrimitiveInt; break;
case 'J': class_root = ClassRoot::kPrimitiveLong; break;
case 'S': class_root = ClassRoot::kPrimitiveShort; break;
case 'Z': class_root = ClassRoot::kPrimitiveBoolean; break;
case 'V': class_root = ClassRoot::kPrimitiveVoid; break;
default:
return nullptr;
}
return GetClassRoot(class_root, this);
}
ObjPtr<mirror::Class> ClassLinker::FindPrimitiveClass(char type) {
ObjPtr<mirror::Class> result = LookupPrimitiveClass(type);
if (UNLIKELY(result == nullptr)) {
std::string printable_type(PrintableChar(type));
ThrowNoClassDefFoundError("Not a primitive type: %s", printable_type.c_str());
}
return result;
}
ObjPtr<mirror::Class> ClassLinker::InsertClass(const char* descriptor,
ObjPtr<mirror::Class> klass,
size_t hash) {
DCHECK(Thread::Current()->CanLoadClasses());
if (VLOG_IS_ON(class_linker)) {
ObjPtr<mirror::DexCache> dex_cache = klass->GetDexCache();
std::string source;
if (dex_cache != nullptr) {
source += " from ";
source += dex_cache->GetLocation()->ToModifiedUtf8();
}
LOG(INFO) << "Loaded class " << descriptor << source;
}
{
WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
const ObjPtr<mirror::ClassLoader> class_loader = klass->GetClassLoader();
ClassTable* const class_table = InsertClassTableForClassLoader(class_loader);
ObjPtr<mirror::Class> existing = class_table->Lookup(descriptor, hash);
if (existing != nullptr) {
return existing;
}
VerifyObject(klass);
class_table->InsertWithHash(klass, hash);
if (class_loader != nullptr) {
// This is necessary because we need to have the card dirtied for remembered sets.
WriteBarrier::ForEveryFieldWrite(class_loader);
}
if (log_new_roots_) {
new_class_roots_.push_back(GcRoot<mirror::Class>(klass));
}
}
if (kIsDebugBuild) {
// Test that copied methods correctly can find their holder.
for (ArtMethod& method : klass->GetCopiedMethods(image_pointer_size_)) {
CHECK_EQ(GetHoldingClassOfCopiedMethod(&method), klass);
}
}
return nullptr;
}
void ClassLinker::WriteBarrierForBootOatFileBssRoots(const OatFile* oat_file) {
WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
DCHECK(!oat_file->GetBssGcRoots().empty()) << oat_file->GetLocation();
if (log_new_roots_ && !ContainsElement(new_bss_roots_boot_oat_files_, oat_file)) {
new_bss_roots_boot_oat_files_.push_back(oat_file);
}
}
// TODO This should really be in mirror::Class.
void ClassLinker::UpdateClassMethods(ObjPtr<mirror::Class> klass,
LengthPrefixedArray<ArtMethod>* new_methods) {
klass->SetMethodsPtrUnchecked(new_methods,
klass->NumDirectMethods(),
klass->NumDeclaredVirtualMethods());
// Need to mark the card so that the remembered sets and mod union tables get updated.
WriteBarrier::ForEveryFieldWrite(klass);
}
ObjPtr<mirror::Class> ClassLinker::LookupClass(Thread* self,
const char* descriptor,
ObjPtr<mirror::ClassLoader> class_loader) {
return LookupClass(self, descriptor, ComputeModifiedUtf8Hash(descriptor), class_loader);
}
ObjPtr<mirror::Class> ClassLinker::LookupClass(Thread* self,
const char* descriptor,
size_t hash,
ObjPtr<mirror::ClassLoader> class_loader) {
ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
ClassTable* const class_table = ClassTableForClassLoader(class_loader);
if (class_table != nullptr) {
ObjPtr<mirror::Class> result = class_table->Lookup(descriptor, hash);
if (result != nullptr) {
return result;
}
}
return nullptr;
}
class MoveClassTableToPreZygoteVisitor : public ClassLoaderVisitor {
public:
MoveClassTableToPreZygoteVisitor() {}
void Visit(ObjPtr<mirror::ClassLoader> class_loader)
REQUIRES(Locks::classlinker_classes_lock_)
REQUIRES_SHARED(Locks::mutator_lock_) override {
ClassTable* const class_table = class_loader->GetClassTable();
if (class_table != nullptr) {
class_table->FreezeSnapshot();
}
}
};
void ClassLinker::MoveClassTableToPreZygote() {
WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
boot_class_table_->FreezeSnapshot();
MoveClassTableToPreZygoteVisitor visitor;
VisitClassLoaders(&visitor);
}
// Look up classes by hash and descriptor and put all matching ones in the result array.
class LookupClassesVisitor : public ClassLoaderVisitor {
public:
LookupClassesVisitor(const char* descriptor,
size_t hash,
std::vector<ObjPtr<mirror::Class>>* result)
: descriptor_(descriptor),
hash_(hash),
result_(result) {}
void Visit(ObjPtr<mirror::ClassLoader> class_loader)
REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_) override {
ClassTable* const class_table = class_loader->GetClassTable();
ObjPtr<mirror::Class> klass = class_table->Lookup(descriptor_, hash_);
// Add `klass` only if `class_loader` is its defining (not just initiating) class loader.
if (klass != nullptr && klass->GetClassLoader() == class_loader) {
result_->push_back(klass);
}
}
private:
const char* const descriptor_;
const size_t hash_;
std::vector<ObjPtr<mirror::Class>>* const result_;
};
void ClassLinker::LookupClasses(const char* descriptor,
std::vector<ObjPtr<mirror::Class>>& result) {
result.clear();
Thread* const self = Thread::Current();
ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
const size_t hash = ComputeModifiedUtf8Hash(descriptor);
ObjPtr<mirror::Class> klass = boot_class_table_->Lookup(descriptor, hash);
if (klass != nullptr) {
DCHECK(klass->GetClassLoader() == nullptr);
result.push_back(klass);
}
LookupClassesVisitor visitor(descriptor, hash, &result);
VisitClassLoaders(&visitor);
}
bool ClassLinker::AttemptSupertypeVerification(Thread* self,
verifier::VerifierDeps* verifier_deps,
Handle<mirror::Class> klass,
Handle<mirror::Class> supertype) {
DCHECK(self != nullptr);
DCHECK(klass != nullptr);
DCHECK(supertype != nullptr);
if (!supertype->IsVerified() && !supertype->IsErroneous()) {
VerifyClass(self, verifier_deps, supertype);
}
if (supertype->IsVerified()
|| supertype->ShouldVerifyAtRuntime()
|| supertype->IsVerifiedNeedsAccessChecks()) {
// The supertype is either verified, or we soft failed at AOT time.
DCHECK(supertype->IsVerified() || Runtime::Current()->IsAotCompiler());
return true;
}
// If we got this far then we have a hard failure.
std::string error_msg =
StringPrintf("Rejecting class %s that attempts to sub-type erroneous class %s",
klass->PrettyDescriptor().c_str(),
supertype->PrettyDescriptor().c_str());
LOG(WARNING) << error_msg << " in " << klass->GetDexCache()->GetLocation()->ToModifiedUtf8();
StackHandleScope<1> hs(self);
Handle<mirror::Throwable> cause(hs.NewHandle(self->GetException()));
if (cause != nullptr) {
// Set during VerifyClass call (if at all).
self->ClearException();
}
// Change into a verify error.
ThrowVerifyError(klass.Get(), "%s", error_msg.c_str());
if (cause != nullptr) {
self->GetException()->SetCause(cause.Get());
}
ClassReference ref(klass->GetDexCache()->GetDexFile(), klass->GetDexClassDefIndex());
if (Runtime::Current()->IsAotCompiler()) {
Runtime::Current()->GetCompilerCallbacks()->ClassRejected(ref);
}
// Need to grab the lock to change status.
ObjectLock<mirror::Class> super_lock(self, klass);
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
return false;
}
verifier::FailureKind ClassLinker::VerifyClass(Thread* self,
verifier::VerifierDeps* verifier_deps,
Handle<mirror::Class> klass,
verifier::HardFailLogMode log_level) {
{
// TODO: assert that the monitor on the Class is held
ObjectLock<mirror::Class> lock(self, klass);
// Is somebody verifying this now?
ClassStatus old_status = klass->GetStatus();
while (old_status == ClassStatus::kVerifying) {
lock.WaitIgnoringInterrupts();
// WaitIgnoringInterrupts can still receive an interrupt and return early, in this
// case we may see the same status again. b/62912904. This is why the check is
// greater or equal.
CHECK(klass->IsErroneous() || (klass->GetStatus() >= old_status))
<< "Class '" << klass->PrettyClass()
<< "' performed an illegal verification state transition from " << old_status
<< " to " << klass->GetStatus();
old_status = klass->GetStatus();
}
// The class might already be erroneous, for example at compile time if we attempted to verify
// this class as a parent to another.
if (klass->IsErroneous()) {
ThrowEarlierClassFailure(klass.Get());
return verifier::FailureKind::kHardFailure;
}
// Don't attempt to re-verify if already verified.
if (klass->IsVerified()) {
if (verifier_deps != nullptr &&
verifier_deps->ContainsDexFile(klass->GetDexFile()) &&
!verifier_deps->HasRecordedVerifiedStatus(klass->GetDexFile(), *klass->GetClassDef()) &&
!Runtime::Current()->IsAotCompiler()) {
// If the klass is verified, but `verifier_deps` did not record it, this
// means we are running background verification of a secondary dex file.
// Re-run the verifier to populate `verifier_deps`.
// No need to run the verification when running on the AOT Compiler, as
// the driver handles those multithreaded cases already.
std::string error_msg;
verifier::FailureKind failure =
PerformClassVerification(self, verifier_deps, klass, log_level, &error_msg);
// We could have soft failures, so just check that we don't have a hard
// failure.
DCHECK_NE(failure, verifier::FailureKind::kHardFailure) << error_msg;
}
return verifier::FailureKind::kNoFailure;
}
if (klass->IsVerifiedNeedsAccessChecks()) {
if (!Runtime::Current()->IsAotCompiler()) {
// Mark the class as having a verification attempt to avoid re-running
// the verifier.
mirror::Class::SetStatus(klass, ClassStatus::kVerified, self);
}
return verifier::FailureKind::kAccessChecksFailure;
}
// For AOT, don't attempt to re-verify if we have already found we should
// verify at runtime.
if (klass->ShouldVerifyAtRuntime()) {
CHECK(Runtime::Current()->IsAotCompiler());
return verifier::FailureKind::kSoftFailure;
}
DCHECK_EQ(klass->GetStatus(), ClassStatus::kResolved);
mirror::Class::SetStatus(klass, ClassStatus::kVerifying, self);
// Skip verification if disabled.
if (!Runtime::Current()->IsVerificationEnabled()) {
mirror::Class::SetStatus(klass, ClassStatus::kVerified, self);
UpdateClassAfterVerification(klass, image_pointer_size_, verifier::FailureKind::kNoFailure);
return verifier::FailureKind::kNoFailure;
}
}
VLOG(class_linker) << "Beginning verification for class: "
<< klass->PrettyDescriptor()
<< " in " << klass->GetDexCache()->GetLocation()->ToModifiedUtf8();
// Verify super class.
StackHandleScope<2> hs(self);
MutableHandle<mirror::Class> supertype(hs.NewHandle(klass->GetSuperClass()));
// If we have a superclass and we get a hard verification failure we can return immediately.
if (supertype != nullptr &&
!AttemptSupertypeVerification(self, verifier_deps, klass, supertype)) {
CHECK(self->IsExceptionPending()) << "Verification error should be pending.";
return verifier::FailureKind::kHardFailure;
}
// Verify all default super-interfaces.
//
// (1) Don't bother if the superclass has already had a soft verification failure.
//
// (2) Interfaces shouldn't bother to do this recursive verification because they cannot cause
// recursive initialization by themselves. This is because when an interface is initialized
// directly it must not initialize its superinterfaces. We are allowed to verify regardless
// but choose not to for an optimization. If the interfaces is being verified due to a class
// initialization (which would need all the default interfaces to be verified) the class code
// will trigger the recursive verification anyway.
if ((supertype == nullptr || supertype->IsVerified()) // See (1)
&& !klass->IsInterface()) { // See (2)
int32_t iftable_count = klass->GetIfTableCount();
MutableHandle<mirror::Class> iface(hs.NewHandle<mirror::Class>(nullptr));
// Loop through all interfaces this class has defined. It doesn't matter the order.
for (int32_t i = 0; i < iftable_count; i++) {
iface.Assign(klass->GetIfTable()->GetInterface(i));
DCHECK(iface != nullptr);
// We only care if we have default interfaces and can skip if we are already verified...
if (LIKELY(!iface->HasDefaultMethods() || iface->IsVerified())) {
continue;
} else if (UNLIKELY(!AttemptSupertypeVerification(self, verifier_deps, klass, iface))) {
// We had a hard failure while verifying this interface. Just return immediately.
CHECK(self->IsExceptionPending()) << "Verification error should be pending.";
return verifier::FailureKind::kHardFailure;
} else if (UNLIKELY(!iface->IsVerified())) {
// We softly failed to verify the iface. Stop checking and clean up.
// Put the iface into the supertype handle so we know what caused us to fail.
supertype.Assign(iface.Get());
break;
}
}
}
// At this point if verification failed, then supertype is the "first" supertype that failed
// verification (without a specific order). If verification succeeded, then supertype is either
// null or the original superclass of klass and is verified.
DCHECK(supertype == nullptr ||
supertype.Get() == klass->GetSuperClass() ||
!supertype->IsVerified());
// Try to use verification information from the oat file, otherwise do runtime verification.
const DexFile& dex_file = *klass->GetDexCache()->GetDexFile();
ClassStatus oat_file_class_status(ClassStatus::kNotReady);
bool preverified = VerifyClassUsingOatFile(self, dex_file, klass, oat_file_class_status);
VLOG(class_linker) << "Class preverified status for class "
<< klass->PrettyDescriptor()
<< " in " << klass->GetDexCache()->GetLocation()->ToModifiedUtf8()
<< ": "
<< preverified
<< "( " << oat_file_class_status << ")";
// If the oat file says the class had an error, re-run the verifier. That way we will either:
// 1) Be successful at runtime, or
// 2) Get a precise error message.
DCHECK(!mirror::Class::IsErroneous(oat_file_class_status) || !preverified);
std::string error_msg;
verifier::FailureKind verifier_failure = verifier::FailureKind::kNoFailure;
if (!preverified) {
verifier_failure = PerformClassVerification(self, verifier_deps, klass, log_level, &error_msg);
} else if (oat_file_class_status == ClassStatus::kVerifiedNeedsAccessChecks) {
verifier_failure = verifier::FailureKind::kAccessChecksFailure;
}
// Verification is done, grab the lock again.
ObjectLock<mirror::Class> lock(self, klass);
self->AssertNoPendingException();
if (verifier_failure == verifier::FailureKind::kHardFailure) {
VLOG(verifier) << "Verification failed on class " << klass->PrettyDescriptor()
<< " in " << klass->GetDexCache()->GetLocation()->ToModifiedUtf8()
<< " because: " << error_msg;
ThrowVerifyError(klass.Get(), "%s", error_msg.c_str());
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
return verifier_failure;
}
// Make sure all classes referenced by catch blocks are resolved.
ResolveClassExceptionHandlerTypes(klass);
if (Runtime::Current()->IsAotCompiler()) {
if (supertype != nullptr && supertype->ShouldVerifyAtRuntime()) {
// Regardless of our own verification result, we need to verify the class
// at runtime if the super class is not verified. This is required in case
// we generate an app/boot image.
verifier_failure = verifier::FailureKind::kSoftFailure;
mirror::Class::SetStatus(klass, ClassStatus::kRetryVerificationAtRuntime, self);
} else if (verifier_failure == verifier::FailureKind::kNoFailure) {
mirror::Class::SetStatus(klass, ClassStatus::kVerified, self);
} else if (verifier_failure == verifier::FailureKind::kSoftFailure ||
verifier_failure == verifier::FailureKind::kTypeChecksFailure) {
mirror::Class::SetStatus(klass, ClassStatus::kRetryVerificationAtRuntime, self);
} else {
mirror::Class::SetStatus(klass, ClassStatus::kVerifiedNeedsAccessChecks, self);
}
// Notify the compiler about the verification status, in case the class
// was verified implicitly (eg super class of a compiled class). When the
// compiler unloads dex file after compilation, we still want to keep
// verification states.
Runtime::Current()->GetCompilerCallbacks()->UpdateClassState(
ClassReference(&klass->GetDexFile(), klass->GetDexClassDefIndex()), klass->GetStatus());
} else {
mirror::Class::SetStatus(klass, ClassStatus::kVerified, self);
}
UpdateClassAfterVerification(klass, image_pointer_size_, verifier_failure);
return verifier_failure;
}
verifier::FailureKind ClassLinker::PerformClassVerification(Thread* self,
verifier::VerifierDeps* verifier_deps,
Handle<mirror::Class> klass,
verifier::HardFailLogMode log_level,
std::string* error_msg) {
Runtime* const runtime = Runtime::Current();
StackHandleScope<2> hs(self);
Handle<mirror::DexCache> dex_cache(hs.NewHandle(klass->GetDexCache()));
Handle<mirror::ClassLoader> class_loader(hs.NewHandle(klass->GetClassLoader()));
return verifier::ClassVerifier::VerifyClass(self,
verifier_deps,
dex_cache->GetDexFile(),
klass,
dex_cache,
class_loader,
*klass->GetClassDef(),
runtime->GetCompilerCallbacks(),
log_level,
Runtime::Current()->GetTargetSdkVersion(),
error_msg);
}
bool ClassLinker::VerifyClassUsingOatFile(Thread* self,
const DexFile& dex_file,
Handle<mirror::Class> klass,
ClassStatus& oat_file_class_status) {
// If we're compiling, we can only verify the class using the oat file if
// we are not compiling the image or if the class we're verifying is not part of
// the compilation unit (app - dependencies). We will let the compiler callback
// tell us about the latter.
if (Runtime::Current()->IsAotCompiler()) {
CompilerCallbacks* callbacks = Runtime::Current()->GetCompilerCallbacks();
// We are compiling an app (not the image).
if (!callbacks->CanUseOatStatusForVerification(klass.Get())) {
return false;
}
}
const OatDexFile* oat_dex_file = dex_file.GetOatDexFile();
// In case we run without an image there won't be a backing oat file.
if (oat_dex_file == nullptr || oat_dex_file->GetOatFile() == nullptr) {
return false;
}
uint16_t class_def_index = klass->GetDexClassDefIndex();
oat_file_class_status = oat_dex_file->GetOatClass(class_def_index).GetStatus();
if (oat_file_class_status >= ClassStatus::kVerified) {
return true;
}
if (oat_file_class_status >= ClassStatus::kVerifiedNeedsAccessChecks) {
// We return that the clas has already been verified, and the caller should
// check the class status to ensure we run with access checks.
return true;
}
// Check the class status with the vdex file.
const OatFile* oat_file = oat_dex_file->GetOatFile();
if (oat_file != nullptr) {
ClassStatus vdex_status = oat_file->GetVdexFile()->ComputeClassStatus(self, klass);
if (vdex_status >= ClassStatus::kVerifiedNeedsAccessChecks) {
VLOG(verifier) << "Vdex verification success for " << klass->PrettyClass();
oat_file_class_status = vdex_status;
return true;
}
}
// If we only verified a subset of the classes at compile time, we can end up with classes that
// were resolved by the verifier.
if (oat_file_class_status == ClassStatus::kResolved) {
return false;
}
// We never expect a .oat file to have kRetryVerificationAtRuntime statuses.
CHECK_NE(oat_file_class_status, ClassStatus::kRetryVerificationAtRuntime)
<< klass->PrettyClass() << " " << dex_file.GetLocation();
if (mirror::Class::IsErroneous(oat_file_class_status)) {
// Compile time verification failed with a hard error. We'll re-run
// verification, which might be successful at runtime.
return false;
}
if (oat_file_class_status == ClassStatus::kNotReady) {
// Status is uninitialized if we couldn't determine the status at compile time, for example,
// not loading the class.
// TODO: when the verifier doesn't rely on Class-es failing to resolve/load the type hierarchy
// isn't a problem and this case shouldn't occur
return false;
}
std::string temp;
LOG(FATAL) << "Unexpected class status: " << oat_file_class_status
<< " " << dex_file.GetLocation() << " " << klass->PrettyClass() << " "
<< klass->GetDescriptor(&temp);
UNREACHABLE();
}
void ClassLinker::ResolveClassExceptionHandlerTypes(Handle<mirror::Class> klass) {
for (ArtMethod& method : klass->GetMethods(image_pointer_size_)) {
ResolveMethodExceptionHandlerTypes(&method);
}
}
void ClassLinker::ResolveMethodExceptionHandlerTypes(ArtMethod* method) {
// similar to DexVerifier::ScanTryCatchBlocks and dex2oat's ResolveExceptionsForMethod.
CodeItemDataAccessor accessor(method->DexInstructionData());
if (!accessor.HasCodeItem()) {
return; // native or abstract method
}
if (accessor.TriesSize() == 0) {
return; // nothing to process
}
const uint8_t* handlers_ptr = accessor.GetCatchHandlerData(0);
uint32_t handlers_size = DecodeUnsignedLeb128(&handlers_ptr);
for (uint32_t idx = 0; idx < handlers_size; idx++) {
CatchHandlerIterator iterator(handlers_ptr);
for (; iterator.HasNext(); iterator.Next()) {
// Ensure exception types are resolved so that they don't need resolution to be delivered,
// unresolved exception types will be ignored by exception delivery
if (iterator.GetHandlerTypeIndex().IsValid()) {
ObjPtr<mirror::Class> exception_type = ResolveType(iterator.GetHandlerTypeIndex(), method);
if (exception_type == nullptr) {
DCHECK(Thread::Current()->IsExceptionPending());
Thread::Current()->ClearException();
}
}
}
handlers_ptr = iterator.EndDataPointer();
}
}
ObjPtr<mirror::Class> ClassLinker::CreateProxyClass(ScopedObjectAccessAlreadyRunnable& soa,
jstring name,
jobjectArray interfaces,
jobject loader,
jobjectArray methods,
jobjectArray throws) {
Thread* self = soa.Self();
// This is to prevent the calls to ClassLoad and ClassPrepare which can cause java/user-supplied
// code to be executed. We put it up here so we can avoid all the allocations associated with
// creating the class. This can happen with (eg) jit-threads.
if (!self->CanLoadClasses()) {
// Make sure we don't try to load anything, potentially causing an infinite loop.
ObjPtr<mirror::Throwable> pre_allocated =
Runtime::Current()->GetPreAllocatedNoClassDefFoundError();
self->SetException(pre_allocated);
return nullptr;
}
StackHandleScope<12> hs(self);
MutableHandle<mirror::Class> temp_klass(hs.NewHandle(
AllocClass(self, GetClassRoot<mirror::Class>(this), sizeof(mirror::Class))));
if (temp_klass == nullptr) {
CHECK(self->IsExceptionPending()); // OOME.
return nullptr;
}
DCHECK(temp_klass->GetClass() != nullptr);
temp_klass->SetObjectSize(sizeof(mirror::Proxy));
// Set the class access flags incl. VerificationAttempted, so we do not try to set the flag on
// the methods.
temp_klass->SetAccessFlagsDuringLinking(kAccClassIsProxy | kAccPublic | kAccFinal);
temp_klass->SetClassLoader(soa.Decode<mirror::ClassLoader>(loader));
DCHECK_EQ(temp_klass->GetPrimitiveType(), Primitive::kPrimNot);
temp_klass->SetName(soa.Decode<mirror::String>(name));
temp_klass->SetDexCache(GetClassRoot<mirror::Proxy>(this)->GetDexCache());
// Object has an empty iftable, copy it for that reason.
temp_klass->SetIfTable(GetClassRoot<mirror::Object>(this)->GetIfTable());
mirror::Class::SetStatus(temp_klass, ClassStatus::kIdx, self);
std::string storage;
const char* descriptor = temp_klass->GetDescriptor(&storage);
const size_t hash = ComputeModifiedUtf8Hash(descriptor);
// Needs to be before we insert the class so that the allocator field is set.
LinearAlloc* const allocator = GetOrCreateAllocatorForClassLoader(temp_klass->GetClassLoader());
// Insert the class before loading the fields as the field roots
// (ArtField::declaring_class_) are only visited from the class
// table. There can't be any suspend points between inserting the
// class and setting the field arrays below.
ObjPtr<mirror::Class> existing = InsertClass(descriptor, temp_klass.Get(), hash);
CHECK(existing == nullptr);
// Instance fields are inherited, but we add a couple of static fields...
const size_t num_fields = 2;
LengthPrefixedArray<ArtField>* sfields = AllocArtFieldArray(self, allocator, num_fields);
temp_klass->SetSFieldsPtr(sfields);
// 1. Create a static field 'interfaces' that holds the _declared_ interfaces implemented by
// our proxy, so Class.getInterfaces doesn't return the flattened set.
ArtField& interfaces_sfield = sfields->At(0);
interfaces_sfield.SetDexFieldIndex(0);
interfaces_sfield.SetDeclaringClass(temp_klass.Get());
interfaces_sfield.SetAccessFlags(kAccStatic | kAccPublic | kAccFinal);
// 2. Create a static field 'throws' that holds exceptions thrown by our methods.
ArtField& throws_sfield = sfields->At(1);
throws_sfield.SetDexFieldIndex(1);
throws_sfield.SetDeclaringClass(temp_klass.Get());
throws_sfield.SetAccessFlags(kAccStatic | kAccPublic | kAccFinal);
// Proxies have 1 direct method, the constructor
const size_t num_direct_methods = 1;
// The array we get passed contains all methods, including private and static
// ones that aren't proxied. We need to filter those out since only interface
// methods (non-private & virtual) are actually proxied.
Handle<mirror::ObjectArray<mirror::Method>> h_methods =
hs.NewHandle(soa.Decode<mirror::ObjectArray<mirror::Method>>(methods));
DCHECK_EQ(h_methods->GetClass(), GetClassRoot<mirror::ObjectArray<mirror::Method>>())
<< mirror::Class::PrettyClass(h_methods->GetClass());
// List of the actual virtual methods this class will have.
std::vector<ArtMethod*> proxied_methods;
std::vector<size_t> proxied_throws_idx;
proxied_methods.reserve(h_methods->GetLength());
proxied_throws_idx.reserve(h_methods->GetLength());
// Filter out to only the non-private virtual methods.
for (auto [mirror, idx] : ZipCount(h_methods.Iterate<mirror::Method>())) {
ArtMethod* m = mirror->GetArtMethod();
if (!m->IsPrivate() && !m->IsStatic()) {
proxied_methods.push_back(m);
proxied_throws_idx.push_back(idx);
}
}
const size_t num_virtual_methods = proxied_methods.size();
// We also need to filter out the 'throws'. The 'throws' are a Class[][] that
// contains an array of all the classes each function is declared to throw.
// This is used to wrap unexpected exceptions in a
// UndeclaredThrowableException exception. This array is in the same order as
// the methods array and like the methods array must be filtered to remove any
// non-proxied methods.
const bool has_filtered_methods =
static_cast<int32_t>(num_virtual_methods) != h_methods->GetLength();
MutableHandle<mirror::ObjectArray<mirror::ObjectArray<mirror::Class>>> original_proxied_throws(
hs.NewHandle(soa.Decode<mirror::ObjectArray<mirror::ObjectArray<mirror::Class>>>(throws)));
MutableHandle<mirror::ObjectArray<mirror::ObjectArray<mirror::Class>>> proxied_throws(
hs.NewHandle<mirror::ObjectArray<mirror::ObjectArray<mirror::Class>>>(
(has_filtered_methods)
? mirror::ObjectArray<mirror::ObjectArray<mirror::Class>>::Alloc(
self, original_proxied_throws->GetClass(), num_virtual_methods)
: original_proxied_throws.Get()));
if (proxied_throws.IsNull() && !original_proxied_throws.IsNull()) {
self->AssertPendingOOMException();
return nullptr;
}
if (has_filtered_methods) {
for (auto [orig_idx, new_idx] : ZipCount(MakeIterationRange(proxied_throws_idx))) {
DCHECK_LE(new_idx, orig_idx);
proxied_throws->Set(new_idx, original_proxied_throws->Get(orig_idx));
}
}
// Create the methods array.
LengthPrefixedArray<ArtMethod>* proxy_class_methods = AllocArtMethodArray(
self, allocator, num_direct_methods + num_virtual_methods);
// Currently AllocArtMethodArray cannot return null, but the OOM logic is left there in case we
// want to throw OOM in the future.
if (UNLIKELY(proxy_class_methods == nullptr)) {
self->AssertPendingOOMException();
return nullptr;
}
temp_klass->SetMethodsPtr(proxy_class_methods, num_direct_methods, num_virtual_methods);
// Create the single direct method.
CreateProxyConstructor(temp_klass, temp_klass->GetDirectMethodUnchecked(0, image_pointer_size_));
// Create virtual method using specified prototypes.
// TODO These should really use the iterators.
for (size_t i = 0; i < num_virtual_methods; ++i) {
auto* virtual_method = temp_klass->GetVirtualMethodUnchecked(i, image_pointer_size_);
auto* prototype = proxied_methods[i];
CreateProxyMethod(temp_klass, prototype, virtual_method);
DCHECK(virtual_method->GetDeclaringClass() != nullptr);
DCHECK(prototype->GetDeclaringClass() != nullptr);
}
// The super class is java.lang.reflect.Proxy
temp_klass->SetSuperClass(GetClassRoot<mirror::Proxy>(this));
// Now effectively in the loaded state.
mirror::Class::SetStatus(temp_klass, ClassStatus::kLoaded, self);
self->AssertNoPendingException();
// At this point the class is loaded. Publish a ClassLoad event.
// Note: this may be a temporary class. It is a listener's responsibility to handle this.
Runtime::Current()->GetRuntimeCallbacks()->ClassLoad(temp_klass);
MutableHandle<mirror::Class> klass = hs.NewHandle<mirror::Class>(nullptr);
{
// Must hold lock on object when resolved.
ObjectLock<mirror::Class> resolution_lock(self, temp_klass);
// Link the fields and virtual methods, creating vtable and iftables.
// The new class will replace the old one in the class table.
Handle<mirror::ObjectArray<mirror::Class>> h_interfaces(
hs.NewHandle(soa.Decode<mirror::ObjectArray<mirror::Class>>(interfaces)));
if (!LinkClass(self, descriptor, temp_klass, h_interfaces, &klass)) {
if (!temp_klass->IsErroneous()) {
mirror::Class::SetStatus(temp_klass, ClassStatus::kErrorUnresolved, self);
}
return nullptr;
}
}
CHECK(temp_klass->IsRetired());
CHECK_NE(temp_klass.Get(), klass.Get());
CHECK_EQ(interfaces_sfield.GetDeclaringClass(), klass.Get());
interfaces_sfield.SetObject<false>(
klass.Get(),
soa.Decode<mirror::ObjectArray<mirror::Class>>(interfaces));
CHECK_EQ(throws_sfield.GetDeclaringClass(), klass.Get());
throws_sfield.SetObject<false>(
klass.Get(),
proxied_throws.Get());
Runtime::Current()->GetRuntimeCallbacks()->ClassPrepare(temp_klass, klass);
// SubtypeCheckInfo::Initialized must happen-before any new-instance for that type.
// See also ClassLinker::EnsureInitialized().
if (kBitstringSubtypeCheckEnabled) {
MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
SubtypeCheck<ObjPtr<mirror::Class>>::EnsureInitialized(klass.Get());
// TODO: Avoid taking subtype_check_lock_ if SubtypeCheck for j.l.r.Proxy is already assigned.
}
VisiblyInitializedCallback* callback = nullptr;
{
// Lock on klass is released. Lock new class object.
ObjectLock<mirror::Class> initialization_lock(self, klass);
// Conservatively go through the ClassStatus::kInitialized state.
callback = MarkClassInitialized(self, klass);
}
if (callback != nullptr) {
callback->MakeVisible(self);
}
// Consistency checks.
if (kIsDebugBuild) {
CHECK(klass->GetIFieldsPtr() == nullptr);
CheckProxyConstructor(klass->GetDirectMethod(0, image_pointer_size_));
for (size_t i = 0; i < num_virtual_methods; ++i) {
auto* virtual_method = klass->GetVirtualMethodUnchecked(i, image_pointer_size_);
CheckProxyMethod(virtual_method, proxied_methods[i]);
}
StackHandleScope<1> hs2(self);
Handle<mirror::String> decoded_name = hs2.NewHandle(soa.Decode<mirror::String>(name));
std::string interfaces_field_name(StringPrintf("java.lang.Class[] %s.interfaces",
decoded_name->ToModifiedUtf8().c_str()));
CHECK_EQ(ArtField::PrettyField(klass->GetStaticField(0)), interfaces_field_name);
std::string throws_field_name(StringPrintf("java.lang.Class[][] %s.throws",
decoded_name->ToModifiedUtf8().c_str()));
CHECK_EQ(ArtField::PrettyField(klass->GetStaticField(1)), throws_field_name);
CHECK_EQ(klass.Get()->GetProxyInterfaces(),
soa.Decode<mirror::ObjectArray<mirror::Class>>(interfaces));
CHECK_EQ(klass.Get()->GetProxyThrows(),
proxied_throws.Get());
}
return klass.Get();
}
void ClassLinker::CreateProxyConstructor(Handle<mirror::Class> klass, ArtMethod* out) {
// Create constructor for Proxy that must initialize the method.
ObjPtr<mirror::Class> proxy_class = GetClassRoot<mirror::Proxy>(this);
CHECK_EQ(proxy_class->NumDirectMethods(), 21u);
// Find the <init>(InvocationHandler)V method. The exact method offset varies depending
// on which front-end compiler was used to build the libcore DEX files.
ArtMethod* proxy_constructor =
jni::DecodeArtMethod(WellKnownClasses::java_lang_reflect_Proxy_init);
DCHECK(proxy_constructor != nullptr)
<< "Could not find <init> method in java.lang.reflect.Proxy";
// Clone the existing constructor of Proxy (our constructor would just invoke it so steal its
// code_ too)
DCHECK(out != nullptr);
out->CopyFrom(proxy_constructor, image_pointer_size_);
// Make this constructor public and fix the class to be our Proxy version.
// Mark kAccCompileDontBother so that we don't take JIT samples for the method. b/62349349
// Note that the compiler calls a ResolveMethod() overload that does not handle a Proxy referrer.
out->SetAccessFlags((out->GetAccessFlags() & ~kAccProtected) |
kAccPublic |
kAccCompileDontBother);
out->SetDeclaringClass(klass.Get());
// Set the original constructor method.
out->SetDataPtrSize(proxy_constructor, image_pointer_size_);
}
void ClassLinker::CheckProxyConstructor(ArtMethod* constructor) const {
CHECK(constructor->IsConstructor());
auto* np = constructor->GetInterfaceMethodIfProxy(image_pointer_size_);
CHECK_STREQ(np->GetName(), "<init>");
CHECK_STREQ(np->GetSignature().ToString().c_str(), "(Ljava/lang/reflect/InvocationHandler;)V");
DCHECK(constructor->IsPublic());
}
void ClassLinker::CreateProxyMethod(Handle<mirror::Class> klass, ArtMethod* prototype,
ArtMethod* out) {
// We steal everything from the prototype (such as DexCache, invoke stub, etc.) then specialize
// as necessary
DCHECK(out != nullptr);
out->CopyFrom(prototype, image_pointer_size_);
// Set class to be the concrete proxy class.
out->SetDeclaringClass(klass.Get());
// Clear the abstract and default flags to ensure that defaults aren't picked in
// preference to the invocation handler.
const uint32_t kRemoveFlags = kAccAbstract | kAccDefault;
// Make the method final.
// Mark kAccCompileDontBother so that we don't take JIT samples for the method. b/62349349
const uint32_t kAddFlags = kAccFinal | kAccCompileDontBother;
out->SetAccessFlags((out->GetAccessFlags() & ~kRemoveFlags) | kAddFlags);
// Set the original interface method.
out->SetDataPtrSize(prototype, image_pointer_size_);
// At runtime the method looks like a reference and argument saving method, clone the code
// related parameters from this method.
out->SetEntryPointFromQuickCompiledCode(GetQuickProxyInvokeHandler());
}
void ClassLinker::CheckProxyMethod(ArtMethod* method, ArtMethod* prototype) const {
// Basic consistency checks.
CHECK(!prototype->IsFinal());
CHECK(method->IsFinal());
CHECK(method->IsInvokable());
// The proxy method doesn't have its own dex cache or dex file and so it steals those of its
// interface prototype. The exception to this are Constructors and the Class of the Proxy itself.
CHECK_EQ(prototype->GetDexMethodIndex(), method->GetDexMethodIndex());
CHECK_EQ(prototype, method->GetInterfaceMethodIfProxy(image_pointer_size_));
}
bool ClassLinker::CanWeInitializeClass(ObjPtr<mirror::Class> klass, bool can_init_statics,
bool can_init_parents) {
if (can_init_statics && can_init_parents) {
return true;
}
if (!can_init_statics) {
// Check if there's a class initializer.
ArtMethod* clinit = klass->FindClassInitializer(image_pointer_size_);
if (clinit != nullptr) {
return false;
}
// Check if there are encoded static values needing initialization.
if (klass->NumStaticFields() != 0) {
const dex::ClassDef* dex_class_def = klass->GetClassDef();
DCHECK(dex_class_def != nullptr);
if (dex_class_def->static_values_off_ != 0) {
return false;
}
}
}
// If we are a class we need to initialize all interfaces with default methods when we are
// initialized. Check all of them.
if (!klass->IsInterface()) {
size_t num_interfaces = klass->GetIfTableCount();
for (size_t i = 0; i < num_interfaces; i++) {
ObjPtr<mirror::Class> iface = klass->GetIfTable()->GetInterface(i);
if (iface->HasDefaultMethods() && !iface->IsInitialized()) {
if (!can_init_parents || !CanWeInitializeClass(iface, can_init_statics, can_init_parents)) {
return false;
}
}
}
}
if (klass->IsInterface() || !klass->HasSuperClass()) {
return true;
}
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
if (super_class->IsInitialized()) {
return true;
}
return can_init_parents && CanWeInitializeClass(super_class, can_init_statics, can_init_parents);
}
bool ClassLinker::InitializeClass(Thread* self,
Handle<mirror::Class> klass,
bool can_init_statics,
bool can_init_parents) {
// see JLS 3rd edition, 12.4.2 "Detailed Initialization Procedure" for the locking protocol
// Are we already initialized and therefore done?
// Note: we differ from the JLS here as we don't do this under the lock, this is benign as
// an initialized class will never change its state.
if (klass->IsInitialized()) {
return true;
}
// Fast fail if initialization requires a full runtime. Not part of the JLS.
if (!CanWeInitializeClass(klass.Get(), can_init_statics, can_init_parents)) {
return false;
}
self->AllowThreadSuspension();
Runtime* const runtime = Runtime::Current();
const bool stats_enabled = runtime->HasStatsEnabled();
uint64_t t0;
{
ObjectLock<mirror::Class> lock(self, klass);
// Re-check under the lock in case another thread initialized ahead of us.
if (klass->IsInitialized()) {
return true;
}
// Was the class already found to be erroneous? Done under the lock to match the JLS.
if (klass->IsErroneous()) {
ThrowEarlierClassFailure(klass.Get(), true, /* log= */ true);
VlogClassInitializationFailure(klass);
return false;
}
CHECK(klass->IsResolved() && !klass->IsErroneousResolved())
<< klass->PrettyClass() << ": state=" << klass->GetStatus();
if (!klass->IsVerified()) {
VerifyClass(self, /*verifier_deps= */ nullptr, klass);
if (!klass->IsVerified()) {
// We failed to verify, expect either the klass to be erroneous or verification failed at
// compile time.
if (klass->IsErroneous()) {
// The class is erroneous. This may be a verifier error, or another thread attempted
// verification and/or initialization and failed. We can distinguish those cases by
// whether an exception is already pending.
if (self->IsExceptionPending()) {
// Check that it's a VerifyError.
DCHECK(IsVerifyError(self->GetException()));
} else {
// Check that another thread attempted initialization.
DCHECK_NE(0, klass->GetClinitThreadId());
DCHECK_NE(self->GetTid(), klass->GetClinitThreadId());
// Need to rethrow the previous failure now.
ThrowEarlierClassFailure(klass.Get(), true);
}
VlogClassInitializationFailure(klass);
} else {
CHECK(Runtime::Current()->IsAotCompiler());
CHECK(klass->ShouldVerifyAtRuntime() || klass->IsVerifiedNeedsAccessChecks());
self->AssertNoPendingException();
self->SetException(Runtime::Current()->GetPreAllocatedNoClassDefFoundError());
}
self->AssertPendingException();
return false;
} else {
self->AssertNoPendingException();
}
// A separate thread could have moved us all the way to initialized. A "simple" example
// involves a subclass of the current class being initialized at the same time (which
// will implicitly initialize the superclass, if scheduled that way). b/28254258
DCHECK(!klass->IsErroneous()) << klass->GetStatus();
if (klass->IsInitialized()) {
return true;
}
}
// If the class is ClassStatus::kInitializing, either this thread is
// initializing higher up the stack or another thread has beat us
// to initializing and we need to wait. Either way, this
// invocation of InitializeClass will not be responsible for
// running <clinit> and will return.
if (klass->GetStatus() == ClassStatus::kInitializing) {
// Could have got an exception during verification.
if (self->IsExceptionPending()) {
VlogClassInitializationFailure(klass);
return false;
}
// We caught somebody else in the act; was it us?
if (klass->GetClinitThreadId() == self->GetTid()) {
// Yes. That's fine. Return so we can continue initializing.
return true;
}
// No. That's fine. Wait for another thread to finish initializing.
return WaitForInitializeClass(klass, self, lock);
}
// Try to get the oat class's status for this class if the oat file is present. The compiler
// tries to validate superclass descriptors, and writes the result into the oat file.
// Runtime correctness is guaranteed by classpath checks done on loading. If the classpath
// is different at runtime than it was at compile time, the oat file is rejected. So if the
// oat file is present, the classpaths must match, and the runtime time check can be skipped.
bool has_oat_class = false;
const OatFile::OatClass oat_class = (runtime->IsStarted() && !runtime->IsAotCompiler())
? OatFile::FindOatClass(klass->GetDexFile(), klass->GetDexClassDefIndex(), &has_oat_class)
: OatFile::OatClass::Invalid();
if (oat_class.GetStatus() < ClassStatus::kSuperclassValidated &&
!ValidateSuperClassDescriptors(klass)) {
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
return false;
}
self->AllowThreadSuspension();
CHECK_EQ(klass->GetStatus(), ClassStatus::kVerified) << klass->PrettyClass()
<< " self.tid=" << self->GetTid() << " clinit.tid=" << klass->GetClinitThreadId();
// From here out other threads may observe that we're initializing and so changes of state
// require the a notification.
klass->SetClinitThreadId(self->GetTid());
mirror::Class::SetStatus(klass, ClassStatus::kInitializing, self);
t0 = stats_enabled ? NanoTime() : 0u;
}
uint64_t t_sub = 0;
// Initialize super classes, must be done while initializing for the JLS.
if (!klass->IsInterface() && klass->HasSuperClass()) {
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
if (!super_class->IsInitialized()) {
CHECK(!super_class->IsInterface());
CHECK(can_init_parents);
StackHandleScope<1> hs(self);
Handle<mirror::Class> handle_scope_super(hs.NewHandle(super_class));
uint64_t super_t0 = stats_enabled ? NanoTime() : 0u;
bool super_initialized = InitializeClass(self, handle_scope_super, can_init_statics, true);
uint64_t super_t1 = stats_enabled ? NanoTime() : 0u;
if (!super_initialized) {
// The super class was verified ahead of entering initializing, we should only be here if
// the super class became erroneous due to initialization.
// For the case of aot compiler, the super class might also be initializing but we don't
// want to process circular dependencies in pre-compile.
CHECK(self->IsExceptionPending())
<< "Super class initialization failed for "
<< handle_scope_super->PrettyDescriptor()
<< " that has unexpected status " << handle_scope_super->GetStatus()
<< "\nPending exception:\n"
<< (self->GetException() != nullptr ? self->GetException()->Dump() : "");
ObjectLock<mirror::Class> lock(self, klass);
// Initialization failed because the super-class is erroneous.
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
return false;
}
t_sub = super_t1 - super_t0;
}
}
if (!klass->IsInterface()) {
// Initialize interfaces with default methods for the JLS.
size_t num_direct_interfaces = klass->NumDirectInterfaces();
// Only setup the (expensive) handle scope if we actually need to.
if (UNLIKELY(num_direct_interfaces > 0)) {
StackHandleScope<1> hs_iface(self);
MutableHandle<mirror::Class> handle_scope_iface(hs_iface.NewHandle<mirror::Class>(nullptr));
for (size_t i = 0; i < num_direct_interfaces; i++) {
handle_scope_iface.Assign(klass->GetDirectInterface(i));
CHECK(handle_scope_iface != nullptr) << klass->PrettyDescriptor() << " iface #" << i;
CHECK(handle_scope_iface->IsInterface());
if (handle_scope_iface->HasBeenRecursivelyInitialized()) {
// We have already done this for this interface. Skip it.
continue;
}
// We cannot just call initialize class directly because we need to ensure that ALL
// interfaces with default methods are initialized. Non-default interface initialization
// will not affect other non-default super-interfaces.
// This is not very precise, misses all walking.
uint64_t inf_t0 = stats_enabled ? NanoTime() : 0u;
bool iface_initialized = InitializeDefaultInterfaceRecursive(self,
handle_scope_iface,
can_init_statics,
can_init_parents);
uint64_t inf_t1 = stats_enabled ? NanoTime() : 0u;
if (!iface_initialized) {
ObjectLock<mirror::Class> lock(self, klass);
// Initialization failed because one of our interfaces with default methods is erroneous.
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
return false;
}
t_sub += inf_t1 - inf_t0;
}
}
}
const size_t num_static_fields = klass->NumStaticFields();
if (num_static_fields > 0) {
const dex::ClassDef* dex_class_def = klass->GetClassDef();
CHECK(dex_class_def != nullptr);
StackHandleScope<3> hs(self);
Handle<mirror::ClassLoader> class_loader(hs.NewHandle(klass->GetClassLoader()));
Handle<mirror::DexCache> dex_cache(hs.NewHandle(klass->GetDexCache()));
// Eagerly fill in static fields so that the we don't have to do as many expensive
// Class::FindStaticField in ResolveField.
for (size_t i = 0; i < num_static_fields; ++i) {
ArtField* field = klass->GetStaticField(i);
const uint32_t field_idx = field->GetDexFieldIndex();
ArtField* resolved_field = dex_cache->GetResolvedField(field_idx);
if (resolved_field == nullptr) {
// Populating cache of a dex file which defines `klass` should always be allowed.
DCHECK(!hiddenapi::ShouldDenyAccessToMember(
field,
hiddenapi::AccessContext(class_loader.Get(), dex_cache.Get()),
hiddenapi::AccessMethod::kNone));
dex_cache->SetResolvedField(field_idx, field);
} else {
DCHECK_EQ(field, resolved_field);
}
}
annotations::RuntimeEncodedStaticFieldValueIterator value_it(dex_cache,
class_loader,
this,
*dex_class_def);
const DexFile& dex_file = *dex_cache->GetDexFile();
if (value_it.HasNext()) {
ClassAccessor accessor(dex_file, *dex_class_def);
CHECK(can_init_statics);
for (const ClassAccessor::Field& field : accessor.GetStaticFields()) {
if (!value_it.HasNext()) {
break;
}
ArtField* art_field = ResolveField(field.GetIndex(),
dex_cache,
class_loader,
/* is_static= */ true);
if (Runtime::Current()->IsActiveTransaction()) {
value_it.ReadValueToField<true>(art_field);
} else {
value_it.ReadValueToField<false>(art_field);
}
if (self->IsExceptionPending()) {
break;
}
value_it.Next();
}
DCHECK(self->IsExceptionPending() || !value_it.HasNext());
}
}
if (!self->IsExceptionPending()) {
ArtMethod* clinit = klass->FindClassInitializer(image_pointer_size_);
if (clinit != nullptr) {
CHECK(can_init_statics);
JValue result;
clinit->Invoke(self, nullptr, 0, &result, "V");
}
}
self->AllowThreadSuspension();
uint64_t t1 = stats_enabled ? NanoTime() : 0u;
VisiblyInitializedCallback* callback = nullptr;
bool success = true;
{
ObjectLock<mirror::Class> lock(self, klass);
if (self->IsExceptionPending()) {
WrapExceptionInInitializer(klass);
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
success = false;
} else if (Runtime::Current()->IsTransactionAborted()) {
// The exception thrown when the transaction aborted has been caught and cleared
// so we need to throw it again now.
VLOG(compiler) << "Return from class initializer of "
<< mirror::Class::PrettyDescriptor(klass.Get())
<< " without exception while transaction was aborted: re-throw it now.";
runtime->ThrowTransactionAbortError(self);
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
success = false;
} else {
if (stats_enabled) {
RuntimeStats* global_stats = runtime->GetStats();
RuntimeStats* thread_stats = self->GetStats();
++global_stats->class_init_count;
++thread_stats->class_init_count;
global_stats->class_init_time_ns += (t1 - t0 - t_sub);
thread_stats->class_init_time_ns += (t1 - t0 - t_sub);
}
// Set the class as initialized except if failed to initialize static fields.
callback = MarkClassInitialized(self, klass);
if (VLOG_IS_ON(class_linker)) {
std::string temp;
LOG(INFO) << "Initialized class " << klass->GetDescriptor(&temp) << " from " <<
klass->GetLocation();
}
}
}
if (callback != nullptr) {
callback->MakeVisible(self);
}
return success;
}
// We recursively run down the tree of interfaces. We need to do this in the order they are declared
// and perform the initialization only on those interfaces that contain default methods.
bool ClassLinker::InitializeDefaultInterfaceRecursive(Thread* self,
Handle<mirror::Class> iface,
bool can_init_statics,
bool can_init_parents) {
CHECK(iface->IsInterface());
size_t num_direct_ifaces = iface->NumDirectInterfaces();
// Only create the (expensive) handle scope if we need it.
if (UNLIKELY(num_direct_ifaces > 0)) {
StackHandleScope<1> hs(self);
MutableHandle<mirror::Class> handle_super_iface(hs.NewHandle<mirror::Class>(nullptr));
// First we initialize all of iface's super-interfaces recursively.
for (size_t i = 0; i < num_direct_ifaces; i++) {
ObjPtr<mirror::Class> super_iface = iface->GetDirectInterface(i);
CHECK(super_iface != nullptr) << iface->PrettyDescriptor() << " iface #" << i;
if (!super_iface->HasBeenRecursivelyInitialized()) {
// Recursive step
handle_super_iface.Assign(super_iface);
if (!InitializeDefaultInterfaceRecursive(self,
handle_super_iface,
can_init_statics,
can_init_parents)) {
return false;
}
}
}
}
bool result = true;
// Then we initialize 'iface' if it has default methods. We do not need to (and in fact must not)
// initialize if we don't have default methods.
if (iface->HasDefaultMethods()) {
result = EnsureInitialized(self, iface, can_init_statics, can_init_parents);
}
// Mark that this interface has undergone recursive default interface initialization so we know we
// can skip it on any later class initializations. We do this even if we are not a default
// interface since we can still avoid the traversal. This is purely a performance optimization.
if (result) {
// TODO This should be done in a better way
// Note: Use a try-lock to avoid blocking when someone else is holding the lock on this
// interface. It is bad (Java) style, but not impossible. Marking the recursive
// initialization is a performance optimization (to avoid another idempotent visit
// for other implementing classes/interfaces), and can be revisited later.
ObjectTryLock<mirror::Class> lock(self, iface);
if (lock.Acquired()) {
iface->SetRecursivelyInitialized();
}
}
return result;
}
bool ClassLinker::WaitForInitializeClass(Handle<mirror::Class> klass,
Thread* self,
ObjectLock<mirror::Class>& lock)
REQUIRES_SHARED(Locks::mutator_lock_) {
while (true) {
self->AssertNoPendingException();
CHECK(!klass->IsInitialized());
lock.WaitIgnoringInterrupts();
// When we wake up, repeat the test for init-in-progress. If
// there's an exception pending (only possible if
// we were not using WaitIgnoringInterrupts), bail out.
if (self->IsExceptionPending()) {
WrapExceptionInInitializer(klass);
mirror::Class::SetStatus(klass, ClassStatus::kErrorResolved, self);
return false;
}
// Spurious wakeup? Go back to waiting.
if (klass->GetStatus() == ClassStatus::kInitializing) {
continue;
}
if (klass->GetStatus() == ClassStatus::kVerified &&
Runtime::Current()->IsAotCompiler()) {
// Compile time initialization failed.
return false;
}
if (klass->IsErroneous()) {
// The caller wants an exception, but it was thrown in a
// different thread. Synthesize one here.
ThrowNoClassDefFoundError("<clinit> failed for class %s; see exception in other thread",
klass->PrettyDescriptor().c_str());
VlogClassInitializationFailure(klass);
return false;
}
if (klass->IsInitialized()) {
return true;
}
LOG(FATAL) << "Unexpected class status. " << klass->PrettyClass() << " is "
<< klass->GetStatus();
}
UNREACHABLE();
}
static void ThrowSignatureCheckResolveReturnTypeException(Handle<mirror::Class> klass,
Handle<mirror::Class> super_klass,
ArtMethod* method,
ArtMethod* m)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(Thread::Current()->IsExceptionPending());
DCHECK(!m->IsProxyMethod());
const DexFile* dex_file = m->GetDexFile();
const dex::MethodId& method_id = dex_file->GetMethodId(m->GetDexMethodIndex());
const dex::ProtoId& proto_id = dex_file->GetMethodPrototype(method_id);
dex::TypeIndex return_type_idx = proto_id.return_type_idx_;
std::string return_type = dex_file->PrettyType(return_type_idx);
std::string class_loader = mirror::Object::PrettyTypeOf(m->GetDeclaringClass()->GetClassLoader());
ThrowWrappedLinkageError(klass.Get(),
"While checking class %s method %s signature against %s %s: "
"Failed to resolve return type %s with %s",
mirror::Class::PrettyDescriptor(klass.Get()).c_str(),
ArtMethod::PrettyMethod(method).c_str(),
super_klass->IsInterface() ? "interface" : "superclass",
mirror::Class::PrettyDescriptor(super_klass.Get()).c_str(),
return_type.c_str(), class_loader.c_str());
}
static void ThrowSignatureCheckResolveArgException(Handle<mirror::Class> klass,
Handle<mirror::Class> super_klass,
ArtMethod* method,
ArtMethod* m,
uint32_t index,
dex::TypeIndex arg_type_idx)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(Thread::Current()->IsExceptionPending());
DCHECK(!m->IsProxyMethod());
const DexFile* dex_file = m->GetDexFile();
std::string arg_type = dex_file->PrettyType(arg_type_idx);
std::string class_loader = mirror::Object::PrettyTypeOf(m->GetDeclaringClass()->GetClassLoader());
ThrowWrappedLinkageError(klass.Get(),
"While checking class %s method %s signature against %s %s: "
"Failed to resolve arg %u type %s with %s",
mirror::Class::PrettyDescriptor(klass.Get()).c_str(),
ArtMethod::PrettyMethod(method).c_str(),
super_klass->IsInterface() ? "interface" : "superclass",
mirror::Class::PrettyDescriptor(super_klass.Get()).c_str(),
index, arg_type.c_str(), class_loader.c_str());
}
static void ThrowSignatureMismatch(Handle<mirror::Class> klass,
Handle<mirror::Class> super_klass,
ArtMethod* method,
const std::string& error_msg)
REQUIRES_SHARED(Locks::mutator_lock_) {
ThrowLinkageError(klass.Get(),
"Class %s method %s resolves differently in %s %s: %s",
mirror::Class::PrettyDescriptor(klass.Get()).c_str(),
ArtMethod::PrettyMethod(method).c_str(),
super_klass->IsInterface() ? "interface" : "superclass",
mirror::Class::PrettyDescriptor(super_klass.Get()).c_str(),
error_msg.c_str());
}
static bool HasSameSignatureWithDifferentClassLoaders(Thread* self,
Handle<mirror::Class> klass,
Handle<mirror::Class> super_klass,
ArtMethod* method1,
ArtMethod* method2)
REQUIRES_SHARED(Locks::mutator_lock_) {
{
StackHandleScope<1> hs(self);
Handle<mirror::Class> return_type(hs.NewHandle(method1->ResolveReturnType()));
if (UNLIKELY(return_type == nullptr)) {
ThrowSignatureCheckResolveReturnTypeException(klass, super_klass, method1, method1);
return false;
}
ObjPtr<mirror::Class> other_return_type = method2->ResolveReturnType();
if (UNLIKELY(other_return_type == nullptr)) {
ThrowSignatureCheckResolveReturnTypeException(klass, super_klass, method1, method2);
return false;
}
if (UNLIKELY(other_return_type != return_type.Get())) {
ThrowSignatureMismatch(klass, super_klass, method1,
StringPrintf("Return types mismatch: %s(%p) vs %s(%p)",
return_type->PrettyClassAndClassLoader().c_str(),
return_type.Get(),
other_return_type->PrettyClassAndClassLoader().c_str(),
other_return_type.Ptr()));
return false;
}
}
const dex::TypeList* types1 = method1->GetParameterTypeList();
const dex::TypeList* types2 = method2->GetParameterTypeList();
if (types1 == nullptr) {
if (types2 != nullptr && types2->Size() != 0) {
ThrowSignatureMismatch(klass, super_klass, method1,
StringPrintf("Type list mismatch with %s",
method2->PrettyMethod(true).c_str()));
return false;
}
return true;
} else if (UNLIKELY(types2 == nullptr)) {
if (types1->Size() != 0) {
ThrowSignatureMismatch(klass, super_klass, method1,
StringPrintf("Type list mismatch with %s",
method2->PrettyMethod(true).c_str()));
return false;
}
return true;
}
uint32_t num_types = types1->Size();
if (UNLIKELY(num_types != types2->Size())) {
ThrowSignatureMismatch(klass, super_klass, method1,
StringPrintf("Type list mismatch with %s",
method2->PrettyMethod(true).c_str()));
return false;
}
for (uint32_t i = 0; i < num_types; ++i) {
StackHandleScope<1> hs(self);
dex::TypeIndex param_type_idx = types1->GetTypeItem(i).type_idx_;
Handle<mirror::Class> param_type(hs.NewHandle(
method1->ResolveClassFromTypeIndex(param_type_idx)));
if (UNLIKELY(param_type == nullptr)) {
ThrowSignatureCheckResolveArgException(klass, super_klass, method1,
method1, i, param_type_idx);
return false;
}
dex::TypeIndex other_param_type_idx = types2->GetTypeItem(i).type_idx_;
ObjPtr<mirror::Class> other_param_type =
method2->ResolveClassFromTypeIndex(other_param_type_idx);
if (UNLIKELY(other_param_type == nullptr)) {
ThrowSignatureCheckResolveArgException(klass, super_klass, method1,
method2, i, other_param_type_idx);
return false;
}
if (UNLIKELY(param_type.Get() != other_param_type)) {
ThrowSignatureMismatch(klass, super_klass, method1,
StringPrintf("Parameter %u type mismatch: %s(%p) vs %s(%p)",
i,
param_type->PrettyClassAndClassLoader().c_str(),
param_type.Get(),
other_param_type->PrettyClassAndClassLoader().c_str(),
other_param_type.Ptr()));
return false;
}
}
return true;
}
bool ClassLinker::ValidateSuperClassDescriptors(Handle<mirror::Class> klass) {
if (klass->IsInterface()) {
return true;
}
// Begin with the methods local to the superclass.
Thread* self = Thread::Current();
StackHandleScope<1> hs(self);
MutableHandle<mirror::Class> super_klass(hs.NewHandle<mirror::Class>(nullptr));
if (klass->HasSuperClass() &&
klass->GetClassLoader() != klass->GetSuperClass()->GetClassLoader()) {
super_klass.Assign(klass->GetSuperClass());
for (int i = klass->GetSuperClass()->GetVTableLength() - 1; i >= 0; --i) {
auto* m = klass->GetVTableEntry(i, image_pointer_size_);
auto* super_m = klass->GetSuperClass()->GetVTableEntry(i, image_pointer_size_);
if (m != super_m) {
if (UNLIKELY(!HasSameSignatureWithDifferentClassLoaders(self,
klass,
super_klass,
m,
super_m))) {
self->AssertPendingException();
return false;
}
}
}
}
for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
super_klass.Assign(klass->GetIfTable()->GetInterface(i));
if (klass->GetClassLoader() != super_klass->GetClassLoader()) {
uint32_t num_methods = super_klass->NumVirtualMethods();
for (uint32_t j = 0; j < num_methods; ++j) {
auto* m = klass->GetIfTable()->GetMethodArray(i)->GetElementPtrSize<ArtMethod*>(
j, image_pointer_size_);
auto* super_m = super_klass->GetVirtualMethod(j, image_pointer_size_);
if (m != super_m) {
if (UNLIKELY(!HasSameSignatureWithDifferentClassLoaders(self,
klass,
super_klass,
m,
super_m))) {
self->AssertPendingException();
return false;
}
}
}
}
}
return true;
}
bool ClassLinker::EnsureInitialized(Thread* self,
Handle<mirror::Class> c,
bool can_init_fields,
bool can_init_parents) {
DCHECK(c != nullptr);
if (c->IsInitialized()) {
// If we've seen an initialized but not visibly initialized class
// many times, request visible initialization.
if (kRuntimeISA == InstructionSet::kX86 || kRuntimeISA == InstructionSet::kX86_64) {
// Thanks to the x86 memory model classes skip the initialized status.
DCHECK(c->IsVisiblyInitialized());
} else if (UNLIKELY(!c->IsVisiblyInitialized())) {
if (self->IncrementMakeVisiblyInitializedCounter()) {
MakeInitializedClassesVisiblyInitialized(self, /*wait=*/ false);
}
}
return true;
}
// SubtypeCheckInfo::Initialized must happen-before any new-instance for that type.
//
// Ensure the bitstring is initialized before any of the class initialization
// logic occurs. Once a class initializer starts running, objects can
// escape into the heap and use the subtype checking code.
//
// Note: A class whose SubtypeCheckInfo is at least Initialized means it
// can be used as a source for the IsSubClass check, and that all ancestors
// of the class are Assigned (can be used as a target for IsSubClass check)
// or Overflowed (can be used as a source for IsSubClass check).
if (kBitstringSubtypeCheckEnabled) {
MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
SubtypeCheck<ObjPtr<mirror::Class>>::EnsureInitialized(c.Get());
// TODO: Avoid taking subtype_check_lock_ if SubtypeCheck is already initialized.
}
const bool success = InitializeClass(self, c, can_init_fields, can_init_parents);
if (!success) {
if (can_init_fields && can_init_parents) {
CHECK(self->IsExceptionPending()) << c->PrettyClass();
} else {
// There may or may not be an exception pending. If there is, clear it.
// We propagate the exception only if we can initialize fields and parents.
self->ClearException();
}
} else {
self->AssertNoPendingException();
}
return success;
}
void ClassLinker::FixupTemporaryDeclaringClass(ObjPtr<mirror::Class> temp_class,
ObjPtr<mirror::Class> new_class) {
DCHECK_EQ(temp_class->NumInstanceFields(), 0u);
for (ArtField& field : new_class->GetIFields()) {
if (field.GetDeclaringClass() == temp_class) {
field.SetDeclaringClass(new_class);
}
}
DCHECK_EQ(temp_class->NumStaticFields(), 0u);
for (ArtField& field : new_class->GetSFields()) {
if (field.GetDeclaringClass() == temp_class) {
field.SetDeclaringClass(new_class);
}
}
DCHECK_EQ(temp_class->NumDirectMethods(), 0u);
DCHECK_EQ(temp_class->NumVirtualMethods(), 0u);
for (auto& method : new_class->GetMethods(image_pointer_size_)) {
if (method.GetDeclaringClass() == temp_class) {
method.SetDeclaringClass(new_class);
}
}
// Make sure the remembered set and mod-union tables know that we updated some of the native
// roots.
WriteBarrier::ForEveryFieldWrite(new_class);
}
void ClassLinker::RegisterClassLoader(ObjPtr<mirror::ClassLoader> class_loader) {
CHECK(class_loader->GetAllocator() == nullptr);
CHECK(class_loader->GetClassTable() == nullptr);
Thread* const self = Thread::Current();
ClassLoaderData data;
data.weak_root = self->GetJniEnv()->GetVm()->AddWeakGlobalRef(self, class_loader);
// Create and set the class table.
data.class_table = new ClassTable;
class_loader->SetClassTable(data.class_table);
// Create and set the linear allocator.
data.allocator = Runtime::Current()->CreateLinearAlloc();
class_loader->SetAllocator(data.allocator);
// Add to the list so that we know to free the data later.
class_loaders_.push_back(data);
}
ClassTable* ClassLinker::InsertClassTableForClassLoader(ObjPtr<mirror::ClassLoader> class_loader) {
if (class_loader == nullptr) {
return boot_class_table_.get();
}
ClassTable* class_table = class_loader->GetClassTable();
if (class_table == nullptr) {
RegisterClassLoader(class_loader);
class_table = class_loader->GetClassTable();
DCHECK(class_table != nullptr);
}
return class_table;
}
ClassTable* ClassLinker::ClassTableForClassLoader(ObjPtr<mirror::ClassLoader> class_loader) {
return class_loader == nullptr ? boot_class_table_.get() : class_loader->GetClassTable();
}
static ImTable* FindSuperImt(ObjPtr<mirror::Class> klass, PointerSize pointer_size)
REQUIRES_SHARED(Locks::mutator_lock_) {
while (klass->HasSuperClass()) {
klass = klass->GetSuperClass();
if (klass->ShouldHaveImt()) {
return klass->GetImt(pointer_size);
}
}
return nullptr;
}
bool ClassLinker::LinkClass(Thread* self,
const char* descriptor,
Handle<mirror::Class> klass,
Handle<mirror::ObjectArray<mirror::Class>> interfaces,
MutableHandle<mirror::Class>* h_new_class_out) {
CHECK_EQ(ClassStatus::kLoaded, klass->GetStatus());
if (!LinkSuperClass(klass)) {
return false;
}
ArtMethod* imt_data[ImTable::kSize];
// If there are any new conflicts compared to super class.
bool new_conflict = false;
std::fill_n(imt_data, arraysize(imt_data), Runtime::Current()->GetImtUnimplementedMethod());
if (!LinkMethods(self, klass, interfaces, &new_conflict, imt_data)) {
return false;
}
if (!LinkInstanceFields(self, klass)) {
return false;
}
size_t class_size;
if (!LinkStaticFields(self, klass, &class_size)) {
return false;
}
CreateReferenceInstanceOffsets(klass);
CHECK_EQ(ClassStatus::kLoaded, klass->GetStatus());
ImTable* imt = nullptr;
if (klass->ShouldHaveImt()) {
// If there are any new conflicts compared to the super class we can not make a copy. There
// can be cases where both will have a conflict method at the same slot without having the same
// set of conflicts. In this case, we can not share the IMT since the conflict table slow path
// will possibly create a table that is incorrect for either of the classes.
// Same IMT with new_conflict does not happen very often.
if (!new_conflict) {
ImTable* super_imt = FindSuperImt(klass.Get(), image_pointer_size_);
if (super_imt != nullptr) {
bool imt_equals = true;
for (size_t i = 0; i < ImTable::kSize && imt_equals; ++i) {
imt_equals = imt_equals && (super_imt->Get(i, image_pointer_size_) == imt_data[i]);
}
if (imt_equals) {
imt = super_imt;
}
}
}
if (imt == nullptr) {
LinearAlloc* allocator = GetAllocatorForClassLoader(klass->GetClassLoader());
imt = reinterpret_cast<ImTable*>(
allocator->Alloc(self, ImTable::SizeInBytes(image_pointer_size_)));
if (imt == nullptr) {
return false;
}
imt->Populate(imt_data, image_pointer_size_);
}
}
if (!klass->IsTemp() || (!init_done_ && klass->GetClassSize() == class_size)) {
// We don't need to retire this class as it has no embedded tables or it was created the
// correct size during class linker initialization.
CHECK_EQ(klass->GetClassSize(), class_size) << klass->PrettyDescriptor();
if (klass->ShouldHaveEmbeddedVTable()) {
klass->PopulateEmbeddedVTable(image_pointer_size_);
}
if (klass->ShouldHaveImt()) {
klass->SetImt(imt, image_pointer_size_);
}
// Update CHA info based on whether we override methods.
// Have to do this before setting the class as resolved which allows
// instantiation of klass.
if (LIKELY(descriptor != nullptr) && cha_ != nullptr) {
cha_->UpdateAfterLoadingOf(klass);
}
// This will notify waiters on klass that saw the not yet resolved
// class in the class_table_ during EnsureResolved.
mirror::Class::SetStatus(klass, ClassStatus::kResolved, self);
h_new_class_out->Assign(klass.Get());
} else {
CHECK(!klass->IsResolved());
// Retire the temporary class and create the correctly sized resolved class.
StackHandleScope<1> hs(self);
Handle<mirror::Class> h_new_class =
hs.NewHandle(mirror::Class::CopyOf(klass, self, class_size, imt, image_pointer_size_));
// Set arrays to null since we don't want to have multiple classes with the same ArtField or
// ArtMethod array pointers. If this occurs, it causes bugs in remembered sets since the GC
// may not see any references to the target space and clean the card for a class if another
// class had the same array pointer.
klass->SetMethodsPtrUnchecked(nullptr, 0, 0);
klass->SetSFieldsPtrUnchecked(nullptr);
klass->SetIFieldsPtrUnchecked(nullptr);
if (UNLIKELY(h_new_class == nullptr)) {
self->AssertPendingOOMException();
mirror::Class::SetStatus(klass, ClassStatus::kErrorUnresolved, self);
return false;
}
CHECK_EQ(h_new_class->GetClassSize(), class_size);
ObjectLock<mirror::Class> lock(self, h_new_class);
FixupTemporaryDeclaringClass(klass.Get(), h_new_class.Get());
if (LIKELY(descriptor != nullptr)) {
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
const ObjPtr<mirror::ClassLoader> class_loader = h_new_class.Get()->GetClassLoader();
ClassTable* const table = InsertClassTableForClassLoader(class_loader);
const ObjPtr<mirror::Class> existing =
table->UpdateClass(descriptor, h_new_class.Get(), ComputeModifiedUtf8Hash(descriptor));
if (class_loader != nullptr) {
// We updated the class in the class table, perform the write barrier so that the GC knows
// about the change.
WriteBarrier::ForEveryFieldWrite(class_loader);
}
CHECK_EQ(existing, klass.Get());
if (log_new_roots_) {
new_class_roots_.push_back(GcRoot<mirror::Class>(h_new_class.Get()));
}
}
// Update CHA info based on whether we override methods.
// Have to do this before setting the class as resolved which allows
// instantiation of klass.
if (LIKELY(descriptor != nullptr) && cha_ != nullptr) {
cha_->UpdateAfterLoadingOf(h_new_class);
}
// This will notify waiters on temp class that saw the not yet resolved class in the
// class_table_ during EnsureResolved.
mirror::Class::SetStatus(klass, ClassStatus::kRetired, self);
CHECK_EQ(h_new_class->GetStatus(), ClassStatus::kResolving);
// This will notify waiters on new_class that saw the not yet resolved
// class in the class_table_ during EnsureResolved.
mirror::Class::SetStatus(h_new_class, ClassStatus::kResolved, self);
// Return the new class.
h_new_class_out->Assign(h_new_class.Get());
}
return true;
}
bool ClassLinker::LoadSuperAndInterfaces(Handle<mirror::Class> klass, const DexFile& dex_file) {
CHECK_EQ(ClassStatus::kIdx, klass->GetStatus());
const dex::ClassDef& class_def = dex_file.GetClassDef(klass->GetDexClassDefIndex());
dex::TypeIndex super_class_idx = class_def.superclass_idx_;
if (super_class_idx.IsValid()) {
// Check that a class does not inherit from itself directly.
//
// TODO: This is a cheap check to detect the straightforward case
// of a class extending itself (b/28685551), but we should do a
// proper cycle detection on loaded classes, to detect all cases
// of class circularity errors (b/28830038).
if (super_class_idx == class_def.class_idx_) {
ThrowClassCircularityError(klass.Get(),
"Class %s extends itself",
klass->PrettyDescriptor().c_str());
return false;
}
ObjPtr<mirror::Class> super_class = ResolveType(super_class_idx, klass.Get());
if (super_class == nullptr) {
DCHECK(Thread::Current()->IsExceptionPending());
return false;
}
// Verify
if (!klass->CanAccess(super_class)) {
ThrowIllegalAccessError(klass.Get(), "Class %s extended by class %s is inaccessible",
super_class->PrettyDescriptor().c_str(),
klass->PrettyDescriptor().c_str());
return false;
}
CHECK(super_class->IsResolved());
klass->SetSuperClass(super_class);
}
const dex::TypeList* interfaces = dex_file.GetInterfacesList(class_def);
if (interfaces != nullptr) {
for (size_t i = 0; i < interfaces->Size(); i++) {
dex::TypeIndex idx = interfaces->GetTypeItem(i).type_idx_;
ObjPtr<mirror::Class> interface = ResolveType(idx, klass.Get());
if (interface == nullptr) {
DCHECK(Thread::Current()->IsExceptionPending());
return false;
}
// Verify
if (!klass->CanAccess(interface)) {
// TODO: the RI seemed to ignore this in my testing.
ThrowIllegalAccessError(klass.Get(),
"Interface %s implemented by class %s is inaccessible",
interface->PrettyDescriptor().c_str(),
klass->PrettyDescriptor().c_str());
return false;
}
}
}
// Mark the class as loaded.
mirror::Class::SetStatus(klass, ClassStatus::kLoaded, nullptr);
return true;
}
bool ClassLinker::LinkSuperClass(Handle<mirror::Class> klass) {
CHECK(!klass->IsPrimitive());
ObjPtr<mirror::Class> super = klass->GetSuperClass();
ObjPtr<mirror::Class> object_class = GetClassRoot<mirror::Object>(this);
if (klass.Get() == object_class) {
if (super != nullptr) {
ThrowClassFormatError(klass.Get(), "java.lang.Object must not have a superclass");
return false;
}
return true;
}
if (super == nullptr) {
ThrowLinkageError(klass.Get(), "No superclass defined for class %s",
klass->PrettyDescriptor().c_str());
return false;
}
// Verify
if (klass->IsInterface() && super != object_class) {
ThrowClassFormatError(klass.Get(), "Interfaces must have java.lang.Object as superclass");
return false;
}
if (super->IsFinal()) {
ThrowVerifyError(klass.Get(),
"Superclass %s of %s is declared final",
super->PrettyDescriptor().c_str(),
klass->PrettyDescriptor().c_str());
return false;
}
if (super->IsInterface()) {
ThrowIncompatibleClassChangeError(klass.Get(),
"Superclass %s of %s is an interface",
super->PrettyDescriptor().c_str(),
klass->PrettyDescriptor().c_str());
return false;
}
if (!klass->CanAccess(super)) {
ThrowIllegalAccessError(klass.Get(), "Superclass %s is inaccessible to class %s",
super->PrettyDescriptor().c_str(),
klass->PrettyDescriptor().c_str());
return false;
}
// Inherit kAccClassIsFinalizable from the superclass in case this
// class doesn't override finalize.
if (super->IsFinalizable()) {
klass->SetFinalizable();
}
// Inherit class loader flag form super class.
if (super->IsClassLoaderClass()) {
klass->SetClassLoaderClass();
}
// Inherit reference flags (if any) from the superclass.
uint32_t reference_flags = (super->GetClassFlags() & mirror::kClassFlagReference);
if (reference_flags != 0) {
CHECK_EQ(klass->GetClassFlags(), 0u);
klass->SetClassFlags(klass->GetClassFlags() | reference_flags);
}
// Disallow custom direct subclasses of java.lang.ref.Reference.
if (init_done_ && super == GetClassRoot<mirror::Reference>(this)) {
ThrowLinkageError(klass.Get(),
"Class %s attempts to subclass java.lang.ref.Reference, which is not allowed",
klass->PrettyDescriptor().c_str());
return false;
}
if (kIsDebugBuild) {
// Ensure super classes are fully resolved prior to resolving fields..
while (super != nullptr) {
CHECK(super->IsResolved());
super = super->GetSuperClass();
}
}
return true;
}
// A wrapper class representing the result of a method translation used for linking methods and
// updating superclass default methods. For each method in a classes vtable there are 4 states it
// could be in:
// 1) No translation is necessary. In this case there is no MethodTranslation object for it. This
// is the standard case and is true when the method is not overridable by a default method,
// the class defines a concrete implementation of the method, the default method implementation
// remains the same, or an abstract method stayed abstract.
// 2) The method must be translated to a different default method. We note this with
// CreateTranslatedMethod.
// 3) The method must be replaced with a conflict method. This happens when a superclass
// implements an interface with a default method and this class implements an unrelated
// interface that also defines that default method. We note this with CreateConflictingMethod.
// 4) The method must be replaced with an abstract miranda method. This happens when a superclass
// implements an interface with a default method and this class implements a subinterface of
// the superclass's interface which declares the default method abstract. We note this with
// CreateAbstractMethod.
//
// When a method translation is unnecessary (case #1), we don't put it into the
// default_translation maps. So an instance of MethodTranslation must be in one of #2-#4.
class ClassLinker::MethodTranslation {
public:
MethodTranslation() : translation_(nullptr), type_(Type::kInvalid) {}
// This slot must become a default conflict method.
static MethodTranslation CreateConflictingMethod() {
return MethodTranslation(Type::kConflict, /*translation=*/nullptr);
}
// This slot must become an abstract method.
static MethodTranslation CreateAbstractMethod() {
return MethodTranslation(Type::kAbstract, /*translation=*/nullptr);
}
// Use the given method as the current value for this vtable slot during translation.
static MethodTranslation CreateTranslatedMethod(ArtMethod* new_method) {
return MethodTranslation(Type::kTranslation, new_method);
}
// Returns true if this is a method that must become a conflict method.
bool IsInConflict() const {
return type_ == Type::kConflict;
}
// Returns true if this is a method that must become an abstract method.
bool IsAbstract() const {
return type_ == Type::kAbstract;
}
// Returns true if this is a method that must become a different method.
bool IsTranslation() const {
return type_ == Type::kTranslation;
}
// Get the translated version of this method.
ArtMethod* GetTranslation() const {
DCHECK(IsTranslation());
DCHECK(translation_ != nullptr);
return translation_;
}
private:
enum class Type {
kInvalid,
kTranslation,
kConflict,
kAbstract,
};
MethodTranslation(Type type, ArtMethod* translation)
: translation_(translation), type_(type) {}
ArtMethod* translation_;
Type type_;
};
// Comparator for name and signature of a method, used in finding overriding methods. Implementation
// avoids the use of handles, if it didn't then rather than compare dex files we could compare dex
// caches in the implementation below.
class MethodNameAndSignatureComparator final : public ValueObject {
public:
explicit MethodNameAndSignatureComparator(ArtMethod* method)
REQUIRES_SHARED(Locks::mutator_lock_) :
dex_file_(method->GetDexFile()), mid_(&dex_file_->GetMethodId(method->GetDexMethodIndex())),
name_view_() {
DCHECK(!method->IsProxyMethod()) << method->PrettyMethod();
}
ALWAYS_INLINE std::string_view GetNameView() {
if (name_view_.empty()) {
name_view_ = dex_file_->StringViewByIdx(mid_->name_idx_);
}
return name_view_;
}
bool HasSameNameAndSignature(ArtMethod* other)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(!other->IsProxyMethod()) << other->PrettyMethod();
const DexFile* other_dex_file = other->GetDexFile();
const dex::MethodId& other_mid = other_dex_file->GetMethodId(other->GetDexMethodIndex());
if (dex_file_ == other_dex_file) {
return mid_->name_idx_ == other_mid.name_idx_ && mid_->proto_idx_ == other_mid.proto_idx_;
}
return GetNameView() == other_dex_file->StringViewByIdx(other_mid.name_idx_) &&
dex_file_->GetMethodSignature(*mid_) == other_dex_file->GetMethodSignature(other_mid);
}
private:
// Dex file for the method to compare against.
const DexFile* const dex_file_;
// MethodId for the method to compare against.
const dex::MethodId* const mid_;
// Lazily computed name from the dex file's strings.
std::string_view name_view_;
};
class LinkVirtualHashTable {
public:
LinkVirtualHashTable(Handle<mirror::Class> klass,
size_t hash_size,
uint32_t* hash_table,
PointerSize image_pointer_size)
: klass_(klass),
hash_size_(hash_size),
hash_table_(hash_table),
image_pointer_size_(image_pointer_size) {
std::fill(hash_table_, hash_table_ + hash_size_, invalid_index_);
}
void Add(uint32_t virtual_method_index) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtMethod* local_method = klass_->GetVirtualMethodDuringLinking(
virtual_method_index, image_pointer_size_);
std::string_view name_view =
local_method->GetInterfaceMethodIfProxy(image_pointer_size_)->GetNameView();
uint32_t hash = ComputeModifiedUtf8Hash(name_view);
uint32_t index = hash % hash_size_;
// Linear probe until we have an empty slot.
while (hash_table_[index] != invalid_index_) {
if (++index == hash_size_) {
index = 0;
}
}
hash_table_[index] = virtual_method_index;
}
uint32_t FindAndRemove(MethodNameAndSignatureComparator* comparator, uint32_t hash)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK_EQ(hash, ComputeModifiedUtf8Hash(comparator->GetNameView()));
size_t index = hash % hash_size_;
while (true) {
const uint32_t value = hash_table_[index];
// Since linear probe makes continuous blocks, hitting an invalid index means we are done
// the block and can safely assume not found.
if (value == invalid_index_) {
break;
}
if (value != removed_index_) { // This signifies not already overriden.
ArtMethod* virtual_method =
klass_->GetVirtualMethodDuringLinking(value, image_pointer_size_);
if (comparator->HasSameNameAndSignature(
virtual_method->GetInterfaceMethodIfProxy(image_pointer_size_))) {
hash_table_[index] = removed_index_;
return value;
}
}
if (++index == hash_size_) {
index = 0;
}
}
return GetNotFoundIndex();
}
static uint32_t GetNotFoundIndex() {
return invalid_index_;
}
private:
static const uint32_t invalid_index_;
static const uint32_t removed_index_;
Handle<mirror::Class> klass_;
const size_t hash_size_;
uint32_t* const hash_table_;
const PointerSize image_pointer_size_;
};
const uint32_t LinkVirtualHashTable::invalid_index_ = std::numeric_limits<uint32_t>::max();
const uint32_t LinkVirtualHashTable::removed_index_ = std::numeric_limits<uint32_t>::max() - 1;
// Determine if the given iface has any subinterface in the given list that declares the method
// specified by 'target'.
//
// Arguments
// - self: The thread we are running on
// - target: A comparator that will match any method that overrides the method we are checking for
// - iftable: The iftable we are searching for an overriding method on.
// - ifstart: The index of the interface we are checking to see if anything overrides
// - iface: The interface we are checking to see if anything overrides.
// - image_pointer_size:
// The image pointer size.
//
// Returns
// - True: There is some method that matches the target comparator defined in an interface that
// is a subtype of iface.
// - False: There is no method that matches the target comparator in any interface that is a subtype
// of iface.
static bool ContainsOverridingMethodOf(Thread* self,
MethodNameAndSignatureComparator& target,
Handle<mirror::IfTable> iftable,
size_t ifstart,
Handle<mirror::Class> iface,
PointerSize image_pointer_size)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(self != nullptr);
DCHECK(iface != nullptr);
DCHECK(iftable != nullptr);
DCHECK_GE(ifstart, 0u);
DCHECK_LT(ifstart, iftable->Count());
DCHECK_EQ(iface.Get(), iftable->GetInterface(ifstart));
DCHECK(iface->IsInterface());
size_t iftable_count = iftable->Count();
StackHandleScope<1> hs(self);
MutableHandle<mirror::Class> current_iface(hs.NewHandle<mirror::Class>(nullptr));
for (size_t k = ifstart + 1; k < iftable_count; k++) {
// Skip ifstart since our current interface obviously cannot override itself.
current_iface.Assign(iftable->GetInterface(k));
// Iterate through every method on this interface. The order does not matter.
for (ArtMethod& current_method : current_iface->GetDeclaredVirtualMethods(image_pointer_size)) {
if (UNLIKELY(target.HasSameNameAndSignature(
current_method.GetInterfaceMethodIfProxy(image_pointer_size)))) {
// Check if the i'th interface is a subtype of this one.
if (iface->IsAssignableFrom(current_iface.Get())) {
return true;
}
break;
}
}
}
return false;
}
// Find the default method implementation for 'interface_method' in 'klass'. Stores it into
// out_default_method and returns kDefaultFound on success. If no default method was found return
// kAbstractFound and store nullptr into out_default_method. If an error occurs (such as a
// default_method conflict) it will return kDefaultConflict.
ClassLinker::DefaultMethodSearchResult ClassLinker::FindDefaultMethodImplementation(
Thread* self,
ArtMethod* target_method,
Handle<mirror::Class> klass,
/*out*/ArtMethod** out_default_method) const {
DCHECK(self != nullptr);
DCHECK(target_method != nullptr);
DCHECK(out_default_method != nullptr);
*out_default_method = nullptr;
// We organize the interface table so that, for interface I any subinterfaces J follow it in the
// table. This lets us walk the table backwards when searching for default methods. The first one
// we encounter is the best candidate since it is the most specific. Once we have found it we keep
// track of it and then continue checking all other interfaces, since we need to throw an error if
// we encounter conflicting default method implementations (one is not a subtype of the other).
//
// The order of unrelated interfaces does not matter and is not defined.
size_t iftable_count = klass->GetIfTableCount();
if (iftable_count == 0) {
// No interfaces. We have already reset out to null so just return kAbstractFound.
return DefaultMethodSearchResult::kAbstractFound;
}
StackHandleScope<3> hs(self);
MutableHandle<mirror::Class> chosen_iface(hs.NewHandle<mirror::Class>(nullptr));
MutableHandle<mirror::IfTable> iftable(hs.NewHandle(klass->GetIfTable()));
MutableHandle<mirror::Class> iface(hs.NewHandle<mirror::Class>(nullptr));
MethodNameAndSignatureComparator target_name_comparator(
target_method->GetInterfaceMethodIfProxy(image_pointer_size_));
// Iterates over the klass's iftable in reverse
for (size_t k = iftable_count; k != 0; ) {
--k;
DCHECK_LT(k, iftable->Count());
iface.Assign(iftable->GetInterface(k));
// Iterate through every declared method on this interface. The order does not matter.
for (auto& method_iter : iface->GetDeclaredVirtualMethods(image_pointer_size_)) {
ArtMethod* current_method = &method_iter;
// Skip abstract methods and methods with different names.
if (current_method->IsAbstract() ||
!target_name_comparator.HasSameNameAndSignature(
current_method->GetInterfaceMethodIfProxy(image_pointer_size_))) {
continue;
} else if (!current_method->IsPublic()) {
// The verifier should have caught the non-public method for dex version 37. Just warn and
// skip it since this is from before default-methods so we don't really need to care that it
// has code.
LOG(WARNING) << "Interface method " << current_method->PrettyMethod()
<< " is not public! "
<< "This will be a fatal error in subsequent versions of android. "
<< "Continuing anyway.";
}
if (UNLIKELY(chosen_iface != nullptr)) {
// We have multiple default impls of the same method. This is a potential default conflict.
// We need to check if this possibly conflicting method is either a superclass of the chosen
// default implementation or is overridden by a non-default interface method. In either case
// there is no conflict.
if (!iface->IsAssignableFrom(chosen_iface.Get()) &&
!ContainsOverridingMethodOf(self,
target_name_comparator,
iftable,
k,
iface,
image_pointer_size_)) {
VLOG(class_linker) << "Conflicting default method implementations found: "
<< current_method->PrettyMethod() << " and "
<< ArtMethod::PrettyMethod(*out_default_method) << " in class "
<< klass->PrettyClass() << " conflict.";
*out_default_method = nullptr;
return DefaultMethodSearchResult::kDefaultConflict;
} else {
break; // Continue checking at the next interface.
}
} else {
// chosen_iface == null
if (!ContainsOverridingMethodOf(self,
target_name_comparator,
iftable,
k,
iface,
image_pointer_size_)) {
// Don't set this as the chosen interface if something else is overriding it (because that
// other interface would be potentially chosen instead if it was default). If the other
// interface was abstract then we wouldn't select this interface as chosen anyway since
// the abstract method masks it.
*out_default_method = current_method;
chosen_iface.Assign(iface.Get());
// We should now finish traversing the graph to find if we have default methods that
// conflict.
} else {
VLOG(class_linker) << "A default method '" << current_method->PrettyMethod()
<< "' was "
<< "skipped because it was overridden by an abstract method in a "
<< "subinterface on class '" << klass->PrettyClass() << "'";
}
}
break;
}
}
if (*out_default_method != nullptr) {
VLOG(class_linker) << "Default method '" << (*out_default_method)->PrettyMethod()
<< "' selected "
<< "as the implementation for '" << target_method->PrettyMethod()
<< "' in '" << klass->PrettyClass() << "'";
return DefaultMethodSearchResult::kDefaultFound;
} else {
return DefaultMethodSearchResult::kAbstractFound;
}
}
ArtMethod* ClassLinker::AddMethodToConflictTable(ObjPtr<mirror::Class> klass,
ArtMethod* conflict_method,
ArtMethod* interface_method,
ArtMethod* method) {
ImtConflictTable* current_table = conflict_method->GetImtConflictTable(kRuntimePointerSize);
Runtime* const runtime = Runtime::Current();
LinearAlloc* linear_alloc = GetAllocatorForClassLoader(klass->GetClassLoader());
// Create a new entry if the existing one is the shared conflict method.
ArtMethod* new_conflict_method = (conflict_method == runtime->GetImtConflictMethod())
? runtime->CreateImtConflictMethod(linear_alloc)
: conflict_method;
// Allocate a new table. Note that we will leak this table at the next conflict,
// but that's a tradeoff compared to making the table fixed size.
void* data = linear_alloc->Alloc(
Thread::Current(), ImtConflictTable::ComputeSizeWithOneMoreEntry(current_table,
image_pointer_size_));
if (data == nullptr) {
LOG(ERROR) << "Failed to allocate conflict table";
return conflict_method;
}
ImtConflictTable* new_table = new (data) ImtConflictTable(current_table,
interface_method,
method,
image_pointer_size_);
// Do a fence to ensure threads see the data in the table before it is assigned
// to the conflict method.
// Note that there is a race in the presence of multiple threads and we may leak
// memory from the LinearAlloc, but that's a tradeoff compared to using
// atomic operations.
std::atomic_thread_fence(std::memory_order_release);
new_conflict_method->SetImtConflictTable(new_table, image_pointer_size_);
return new_conflict_method;
}
bool ClassLinker::AllocateIfTableMethodArrays(Thread* self,
Handle<mirror::Class> klass,
Handle<mirror::IfTable> iftable) {
DCHECK(!klass->IsInterface());
const bool has_superclass = klass->HasSuperClass();
const bool extend_super_iftable = has_superclass;
const size_t ifcount = klass->GetIfTableCount();
const size_t super_ifcount = has_superclass ? klass->GetSuperClass()->GetIfTableCount() : 0U;
for (size_t i = 0; i < ifcount; ++i) {
size_t num_methods = iftable->GetInterface(i)->NumDeclaredVirtualMethods();
if (num_methods > 0) {
const bool is_super = i < super_ifcount;
// This is an interface implemented by a super-class. Therefore we can just copy the method
// array from the superclass.
const bool super_interface = is_super && extend_super_iftable;
ObjPtr<mirror::PointerArray> method_array;
if (super_interface) {
ObjPtr<mirror::IfTable> if_table = klass->GetSuperClass()->GetIfTable();
DCHECK(if_table != nullptr);
DCHECK(if_table->GetMethodArray(i) != nullptr);
// If we are working on a super interface, try extending the existing method array.
StackHandleScope<1u> hs(self);
Handle<mirror::PointerArray> old_array = hs.NewHandle(if_table->GetMethodArray(i));
method_array =
ObjPtr<mirror::PointerArray>::DownCast(mirror::Object::Clone(old_array, self));
} else {
method_array = AllocPointerArray(self, num_methods);
}
if (UNLIKELY(method_array == nullptr)) {
self->AssertPendingOOMException();
return false;
}
iftable->SetMethodArray(i, method_array);
}
}
return true;
}
void ClassLinker::SetIMTRef(ArtMethod* unimplemented_method,
ArtMethod* imt_conflict_method,
ArtMethod* current_method,
/*out*/bool* new_conflict,
/*out*/ArtMethod** imt_ref) {
// Place method in imt if entry is empty, place conflict otherwise.
if (*imt_ref == unimplemented_method) {
*imt_ref = current_method;
} else if (!(*imt_ref)->IsRuntimeMethod()) {
// If we are not a conflict and we have the same signature and name as the imt
// entry, it must be that we overwrote a superclass vtable entry.
// Note that we have checked IsRuntimeMethod, as there may be multiple different
// conflict methods.
MethodNameAndSignatureComparator imt_comparator(
(*imt_ref)->GetInterfaceMethodIfProxy(image_pointer_size_));
if (imt_comparator.HasSameNameAndSignature(
current_method->GetInterfaceMethodIfProxy(image_pointer_size_))) {
*imt_ref = current_method;
} else {
*imt_ref = imt_conflict_method;
*new_conflict = true;
}
} else {
// Place the default conflict method. Note that there may be an existing conflict
// method in the IMT, but it could be one tailored to the super class, with a
// specific ImtConflictTable.
*imt_ref = imt_conflict_method;
*new_conflict = true;
}
}
void ClassLinker::FillIMTAndConflictTables(ObjPtr<mirror::Class> klass) {
DCHECK(klass->ShouldHaveImt()) << klass->PrettyClass();
DCHECK(!klass->IsTemp()) << klass->PrettyClass();
ArtMethod* imt_data[ImTable::kSize];
Runtime* const runtime = Runtime::Current();
ArtMethod* const unimplemented_method = runtime->GetImtUnimplementedMethod();
ArtMethod* const conflict_method = runtime->GetImtConflictMethod();
std::fill_n(imt_data, arraysize(imt_data), unimplemented_method);
if (klass->GetIfTable() != nullptr) {
bool new_conflict = false;
FillIMTFromIfTable(klass->GetIfTable(),
unimplemented_method,
conflict_method,
klass,
/*create_conflict_tables=*/true,
/*ignore_copied_methods=*/false,
&new_conflict,
&imt_data[0]);
}
// Compare the IMT with the super class including the conflict methods. If they are equivalent,
// we can just use the same pointer.
ImTable* imt = nullptr;
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
if (super_class != nullptr && super_class->ShouldHaveImt()) {
ImTable* super_imt = super_class->GetImt(image_pointer_size_);
bool same = true;
for (size_t i = 0; same && i < ImTable::kSize; ++i) {
ArtMethod* method = imt_data[i];
ArtMethod* super_method = super_imt->Get(i, image_pointer_size_);
if (method != super_method) {
bool is_conflict_table = method->IsRuntimeMethod() &&
method != unimplemented_method &&
method != conflict_method;
// Verify conflict contents.
bool super_conflict_table = super_method->IsRuntimeMethod() &&
super_method != unimplemented_method &&
super_method != conflict_method;
if (!is_conflict_table || !super_conflict_table) {
same = false;
} else {
ImtConflictTable* table1 = method->GetImtConflictTable(image_pointer_size_);
ImtConflictTable* table2 = super_method->GetImtConflictTable(image_pointer_size_);
same = same && table1->Equals(table2, image_pointer_size_);
}
}
}
if (same) {
imt = super_imt;
}
}
if (imt == nullptr) {
imt = klass->GetImt(image_pointer_size_);
DCHECK(imt != nullptr);
imt->Populate(imt_data, image_pointer_size_);
} else {
klass->SetImt(imt, image_pointer_size_);
}
}
ImtConflictTable* ClassLinker::CreateImtConflictTable(size_t count,
LinearAlloc* linear_alloc,
PointerSize image_pointer_size) {
void* data = linear_alloc->Alloc(Thread::Current(),
ImtConflictTable::ComputeSize(count,
image_pointer_size));
return (data != nullptr) ? new (data) ImtConflictTable(count, image_pointer_size) : nullptr;
}
ImtConflictTable* ClassLinker::CreateImtConflictTable(size_t count, LinearAlloc* linear_alloc) {
return CreateImtConflictTable(count, linear_alloc, image_pointer_size_);
}
void ClassLinker::FillIMTFromIfTable(ObjPtr<mirror::IfTable> if_table,
ArtMethod* unimplemented_method,
ArtMethod* imt_conflict_method,
ObjPtr<mirror::Class> klass,
bool create_conflict_tables,
bool ignore_copied_methods,
/*out*/bool* new_conflict,
/*out*/ArtMethod** imt) {
uint32_t conflict_counts[ImTable::kSize] = {};
for (size_t i = 0, length = if_table->Count(); i < length; ++i) {
ObjPtr<mirror::Class> interface = if_table->GetInterface(i);
const size_t num_virtuals = interface->NumVirtualMethods();
const size_t method_array_count = if_table->GetMethodArrayCount(i);
// Virtual methods can be larger than the if table methods if there are default methods.
DCHECK_GE(num_virtuals, method_array_count);
if (kIsDebugBuild) {
if (klass->IsInterface()) {
DCHECK_EQ(method_array_count, 0u);
} else {
DCHECK_EQ(interface->NumDeclaredVirtualMethods(), method_array_count);
}
}
if (method_array_count == 0) {
continue;
}
ObjPtr<mirror::PointerArray> method_array = if_table->GetMethodArray(i);
for (size_t j = 0; j < method_array_count; ++j) {
ArtMethod* implementation_method =
method_array->GetElementPtrSize<ArtMethod*>(j, image_pointer_size_);
if (ignore_copied_methods && implementation_method->IsCopied()) {
continue;
}
DCHECK(implementation_method != nullptr);
// Miranda methods cannot be used to implement an interface method, but they are safe to put
// in the IMT since their entrypoint is the interface trampoline. If we put any copied methods
// or interface methods in the IMT here they will not create extra conflicts since we compare
// names and signatures in SetIMTRef.
ArtMethod* interface_method = interface->GetVirtualMethod(j, image_pointer_size_);
const uint32_t imt_index = interface_method->GetImtIndex();
// There is only any conflicts if all of the interface methods for an IMT slot don't have
// the same implementation method, keep track of this to avoid creating a conflict table in
// this case.
// Conflict table size for each IMT slot.
++conflict_counts[imt_index];
SetIMTRef(unimplemented_method,
imt_conflict_method,
implementation_method,
/*out*/new_conflict,
/*out*/&imt[imt_index]);
}
}
if (create_conflict_tables) {
// Create the conflict tables.
LinearAlloc* linear_alloc = GetAllocatorForClassLoader(klass->GetClassLoader());
for (size_t i = 0; i < ImTable::kSize; ++i) {
size_t conflicts = conflict_counts[i];
if (imt[i] == imt_conflict_method) {
ImtConflictTable* new_table = CreateImtConflictTable(conflicts, linear_alloc);
if (new_table != nullptr) {
ArtMethod* new_conflict_method =
Runtime::Current()->CreateImtConflictMethod(linear_alloc);
new_conflict_method->SetImtConflictTable(new_table, image_pointer_size_);
imt[i] = new_conflict_method;
} else {
LOG(ERROR) << "Failed to allocate conflict table";
imt[i] = imt_conflict_method;
}
} else {
DCHECK_NE(imt[i], imt_conflict_method);
}
}
for (size_t i = 0, length = if_table->Count(); i < length; ++i) {
ObjPtr<mirror::Class> interface = if_table->GetInterface(i);
const size_t method_array_count = if_table->GetMethodArrayCount(i);
// Virtual methods can be larger than the if table methods if there are default methods.
if (method_array_count == 0) {
continue;
}
ObjPtr<mirror::PointerArray> method_array = if_table->GetMethodArray(i);
for (size_t j = 0; j < method_array_count; ++j) {
ArtMethod* implementation_method =
method_array->GetElementPtrSize<ArtMethod*>(j, image_pointer_size_);
if (ignore_copied_methods && implementation_method->IsCopied()) {
continue;
}
DCHECK(implementation_method != nullptr);
ArtMethod* interface_method = interface->GetVirtualMethod(j, image_pointer_size_);
const uint32_t imt_index = interface_method->GetImtIndex();
if (!imt[imt_index]->IsRuntimeMethod() ||
imt[imt_index] == unimplemented_method ||
imt[imt_index] == imt_conflict_method) {
continue;
}
ImtConflictTable* table = imt[imt_index]->GetImtConflictTable(image_pointer_size_);
const size_t num_entries = table->NumEntries(image_pointer_size_);
table->SetInterfaceMethod(num_entries, image_pointer_size_, interface_method);
table->SetImplementationMethod(num_entries, image_pointer_size_, implementation_method);
}
}
}
}
// Simple helper function that checks that no subtypes of 'val' are contained within the 'classes'
// set.
static bool NotSubinterfaceOfAny(
const HashSet<mirror::Class*>& classes,
ObjPtr<mirror::Class> val)
REQUIRES(Roles::uninterruptible_)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(val != nullptr);
for (ObjPtr<mirror::Class> c : classes) {
if (val->IsAssignableFrom(c)) {
return false;
}
}
return true;
}
// Fills in and flattens the interface inheritance hierarchy.
//
// By the end of this function all interfaces in the transitive closure of to_process are added to
// the iftable and every interface precedes all of its sub-interfaces in this list.
//
// all I, J: Interface | I <: J implies J precedes I
//
// (note A <: B means that A is a subtype of B)
//
// This returns the total number of items in the iftable. The iftable might be resized down after
// this call.
//
// We order this backwards so that we do not need to reorder superclass interfaces when new
// interfaces are added in subclass's interface tables.
//
// Upon entry into this function iftable is a copy of the superclass's iftable with the first
// super_ifcount entries filled in with the transitive closure of the interfaces of the superclass.
// The other entries are uninitialized. We will fill in the remaining entries in this function. The
// iftable must be large enough to hold all interfaces without changing its size.
static size_t FillIfTable(ObjPtr<mirror::Class> klass,
ObjPtr<mirror::ObjectArray<mirror::Class>> interfaces,
ObjPtr<mirror::IfTable> iftable,
size_t super_ifcount,
size_t num_interfaces)
REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedAssertNoThreadSuspension nts(__FUNCTION__);
// This is the set of all classes already in the iftable. Used to make checking
// if a class has already been added quicker.
constexpr size_t kBufferSize = 32; // 256 bytes on 64-bit architectures.
mirror::Class* buffer[kBufferSize];
HashSet<mirror::Class*> classes_in_iftable(buffer, kBufferSize);
// The first super_ifcount elements are from the superclass. We note that they are already added.
for (size_t i = 0; i < super_ifcount; i++) {
ObjPtr<mirror::Class> iface = iftable->GetInterface(i);
DCHECK(NotSubinterfaceOfAny(classes_in_iftable, iface)) << "Bad ordering.";
classes_in_iftable.insert(iface.Ptr());
}
size_t filled_ifcount = super_ifcount;
const bool have_interfaces = interfaces != nullptr;
for (size_t i = 0; i != num_interfaces; ++i) {
ObjPtr<mirror::Class> interface =
have_interfaces ? interfaces->Get(i) : klass->GetDirectInterface(i);
// Let us call the first filled_ifcount elements of iftable the current-iface-list.
// At this point in the loop current-iface-list has the invariant that:
// for every pair of interfaces I,J within it:
// if index_of(I) < index_of(J) then I is not a subtype of J
// If we have already seen this element then all of its super-interfaces must already be in the
// current-iface-list so we can skip adding it.
if (classes_in_iftable.find(interface.Ptr()) == classes_in_iftable.end()) {
// We haven't seen this interface so add all of its super-interfaces onto the
// current-iface-list, skipping those already on it.
int32_t ifcount = interface->GetIfTableCount();
for (int32_t j = 0; j < ifcount; j++) {
ObjPtr<mirror::Class> super_interface = interface->GetIfTable()->GetInterface(j);
if (!ContainsElement(classes_in_iftable, super_interface)) {
DCHECK(NotSubinterfaceOfAny(classes_in_iftable, super_interface)) << "Bad ordering.";
classes_in_iftable.insert(super_interface.Ptr());
iftable->SetInterface(filled_ifcount, super_interface);
filled_ifcount++;
}
}
DCHECK(NotSubinterfaceOfAny(classes_in_iftable, interface)) << "Bad ordering";
// Place this interface onto the current-iface-list after all of its super-interfaces.
classes_in_iftable.insert(interface.Ptr());
iftable->SetInterface(filled_ifcount, interface);
filled_ifcount++;
} else if (kIsDebugBuild) {
// Check all super-interfaces are already in the list.
int32_t ifcount = interface->GetIfTableCount();
for (int32_t j = 0; j < ifcount; j++) {
ObjPtr<mirror::Class> super_interface = interface->GetIfTable()->GetInterface(j);
DCHECK(ContainsElement(classes_in_iftable, super_interface))
<< "Iftable does not contain " << mirror::Class::PrettyClass(super_interface)
<< ", a superinterface of " << interface->PrettyClass();
}
}
}
if (kIsDebugBuild) {
// Check that the iftable is ordered correctly.
for (size_t i = 0; i < filled_ifcount; i++) {
ObjPtr<mirror::Class> if_a = iftable->GetInterface(i);
for (size_t j = i + 1; j < filled_ifcount; j++) {
ObjPtr<mirror::Class> if_b = iftable->GetInterface(j);
// !(if_a <: if_b)
CHECK(!if_b->IsAssignableFrom(if_a))
<< "Bad interface order: " << mirror::Class::PrettyClass(if_a) << " (index " << i
<< ") extends "
<< if_b->PrettyClass() << " (index " << j << ") and so should be after it in the "
<< "interface list.";
}
}
}
return filled_ifcount;
}
bool ClassLinker::SetupInterfaceLookupTable(Thread* self,
Handle<mirror::Class> klass,
Handle<mirror::ObjectArray<mirror::Class>> interfaces) {
StackHandleScope<1> hs(self);
const bool has_superclass = klass->HasSuperClass();
const size_t super_ifcount = has_superclass ? klass->GetSuperClass()->GetIfTableCount() : 0U;
const bool have_interfaces = interfaces != nullptr;
const size_t num_interfaces =
have_interfaces ? interfaces->GetLength() : klass->NumDirectInterfaces();
if (num_interfaces == 0) {
if (super_ifcount == 0) {
if (LIKELY(has_superclass)) {
klass->SetIfTable(klass->GetSuperClass()->GetIfTable());
}
// Class implements no interfaces.
DCHECK_EQ(klass->GetIfTableCount(), 0);
return true;
}
// Class implements same interfaces as parent, are any of these not marker interfaces?
bool has_non_marker_interface = false;
ObjPtr<mirror::IfTable> super_iftable = klass->GetSuperClass()->GetIfTable();
for (size_t i = 0; i < super_ifcount; ++i) {
if (super_iftable->GetMethodArrayCount(i) > 0) {
has_non_marker_interface = true;
break;
}
}
// Class just inherits marker interfaces from parent so recycle parent's iftable.
if (!has_non_marker_interface) {
klass->SetIfTable(super_iftable);
return true;
}
}
size_t ifcount = super_ifcount + num_interfaces;
// Check that every class being implemented is an interface.
for (size_t i = 0; i < num_interfaces; i++) {
ObjPtr<mirror::Class> interface =
have_interfaces ? interfaces->GetWithoutChecks(i) : klass->GetDirectInterface(i);
DCHECK(interface != nullptr);
if (UNLIKELY(!interface->IsInterface())) {
std::string temp;
ThrowIncompatibleClassChangeError(klass.Get(),
"Class %s implements non-interface class %s",
klass->PrettyDescriptor().c_str(),
PrettyDescriptor(interface->GetDescriptor(&temp)).c_str());
return false;
}
ifcount += interface->GetIfTableCount();
}
// Create the interface function table.
MutableHandle<mirror::IfTable> iftable(hs.NewHandle(AllocIfTable(self, ifcount)));
if (UNLIKELY(iftable == nullptr)) {
self->AssertPendingOOMException();
return false;
}
// Fill in table with superclass's iftable.
if (super_ifcount != 0) {
ObjPtr<mirror::IfTable> super_iftable = klass->GetSuperClass()->GetIfTable();
for (size_t i = 0; i < super_ifcount; i++) {
ObjPtr<mirror::Class> super_interface = super_iftable->GetInterface(i);
iftable->SetInterface(i, super_interface);
}
}
// Note that AllowThreadSuspension is to thread suspension as pthread_testcancel is to pthread
// cancellation. That is it will suspend if one has a pending suspend request but otherwise
// doesn't really do anything.
self->AllowThreadSuspension();
const size_t new_ifcount =
FillIfTable(klass.Get(), interfaces.Get(), iftable.Get(), super_ifcount, num_interfaces);
self->AllowThreadSuspension();
// Shrink iftable in case duplicates were found
if (new_ifcount < ifcount) {
DCHECK_NE(num_interfaces, 0U);
iftable.Assign(ObjPtr<mirror::IfTable>::DownCast(
mirror::IfTable::CopyOf(iftable, self, new_ifcount * mirror::IfTable::kMax)));
if (UNLIKELY(iftable == nullptr)) {
self->AssertPendingOOMException();
return false;
}
ifcount = new_ifcount;
} else {
DCHECK_EQ(new_ifcount, ifcount);
}
klass->SetIfTable(iftable.Get());
return true;
}
// Finds the method with a name/signature that matches cmp in the given lists of methods. The list
// of methods must be unique.
static ArtMethod* FindSameNameAndSignature(MethodNameAndSignatureComparator& cmp ATTRIBUTE_UNUSED) {
return nullptr;
}
template <typename ... Types>
static ArtMethod* FindSameNameAndSignature(MethodNameAndSignatureComparator& cmp,
const ScopedArenaVector<ArtMethod*>& list,
const Types& ... rest)
REQUIRES_SHARED(Locks::mutator_lock_) {
for (ArtMethod* method : list) {
if (cmp.HasSameNameAndSignature(method)) {
return method;
}
}
return FindSameNameAndSignature(cmp, rest...);
}
namespace {
// Check that all vtable entries are present in this class's virtuals or are the same as a
// superclasses vtable entry.
void CheckClassOwnsVTableEntries(Thread* self,
Handle<mirror::Class> klass,
PointerSize pointer_size)
REQUIRES_SHARED(Locks::mutator_lock_) {
StackHandleScope<2> hs(self);
Handle<mirror::PointerArray> check_vtable(hs.NewHandle(klass->GetVTableDuringLinking()));
ObjPtr<mirror::Class> super_temp = (klass->HasSuperClass()) ? klass->GetSuperClass() : nullptr;
Handle<mirror::Class> superclass(hs.NewHandle(super_temp));
int32_t super_vtable_length = (superclass != nullptr) ? superclass->GetVTableLength() : 0;
for (int32_t i = 0; i < check_vtable->GetLength(); ++i) {
ArtMethod* m = check_vtable->GetElementPtrSize<ArtMethod*>(i, pointer_size);
CHECK(m != nullptr);
if (m->GetMethodIndexDuringLinking() != i) {
LOG(WARNING) << m->PrettyMethod()
<< " has an unexpected method index for its spot in the vtable for class"
<< klass->PrettyClass();
}
ArraySlice<ArtMethod> virtuals = klass->GetVirtualMethodsSliceUnchecked(pointer_size);
auto is_same_method = [m] (const ArtMethod& meth) {
return &meth == m;
};
if (!((super_vtable_length > i && superclass->GetVTableEntry(i, pointer_size) == m) ||
std::find_if(virtuals.begin(), virtuals.end(), is_same_method) != virtuals.end())) {
LOG(WARNING) << m->PrettyMethod() << " does not seem to be owned by current class "
<< klass->PrettyClass() << " or any of its superclasses!";
}
}
}
// Check to make sure the vtable does not have duplicates. Duplicates could cause problems when a
// method is overridden in a subclass.
template <PointerSize kPointerSize>
void CheckVTableHasNoDuplicates(Thread* self, Handle<mirror::Class> klass)
REQUIRES_SHARED(Locks::mutator_lock_) {
StackHandleScope<1> hs(self);
Handle<mirror::PointerArray> vtable(hs.NewHandle(klass->GetVTableDuringLinking()));
int32_t num_entries = vtable->GetLength();
// Observations:
// * The older implementation was O(n^2) and got too expensive for apps with larger classes.
// * Many classes do not override Object functions (e.g., equals/hashCode/toString). Thus,
// for many classes outside of libcore a cross-dexfile check has to be run anyways.
// * In the cross-dexfile case, with the O(n^2), in the best case O(n) cross checks would have
// to be done. It is thus OK in a single-pass algorithm to read all data, anyways.
// * The single-pass algorithm will trade memory for speed, but that is OK.
CHECK_GT(num_entries, 0);
auto log_fn = [&vtable, &klass](int32_t i, int32_t j) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtMethod* m1 = vtable->GetElementPtrSize<ArtMethod*, kPointerSize>(i);
ArtMethod* m2 = vtable->GetElementPtrSize<ArtMethod*, kPointerSize>(j);
LOG(WARNING) << "vtable entries " << i << " and " << j << " are identical for "
<< klass->PrettyClass() << " in method " << m1->PrettyMethod()
<< " (0x" << std::hex << reinterpret_cast<uintptr_t>(m2) << ") and "
<< m2->PrettyMethod() << " (0x" << std::hex
<< reinterpret_cast<uintptr_t>(m2) << ")";
};
struct BaseHashType {
static size_t HashCombine(size_t seed, size_t val) {
return seed ^ (val + 0x9e3779b9 + (seed << 6) + (seed >> 2));
}
};
// Check assuming all entries come from the same dex file.
{
// Find the first interesting method and its dex file.
int32_t start = 0;
for (; start < num_entries; ++start) {
ArtMethod* vtable_entry = vtable->GetElementPtrSize<ArtMethod*, kPointerSize>(start);
// Don't bother if we cannot 'see' the vtable entry (i.e. it is a package-private member
// maybe).
if (!klass->CanAccessMember(vtable_entry->GetDeclaringClass(),
vtable_entry->GetAccessFlags())) {
continue;
}
break;
}
if (start == num_entries) {
return;
}
const DexFile* dex_file =
vtable->GetElementPtrSize<ArtMethod*, kPointerSize>(start)->
GetInterfaceMethodIfProxy(kPointerSize)->GetDexFile();
// Helper function to avoid logging if we have to run the cross-file checks.
auto check_fn = [&](bool log_warn) REQUIRES_SHARED(Locks::mutator_lock_) {
// Use a map to store seen entries, as the storage space is too large for a bitvector.
using PairType = std::pair<uint32_t, uint16_t>;
struct PairHash : BaseHashType {
size_t operator()(const PairType& key) const {
return BaseHashType::HashCombine(BaseHashType::HashCombine(0, key.first), key.second);
}
};
HashMap<PairType, int32_t, DefaultMapEmptyFn<PairType, int32_t>, PairHash> seen;
seen.reserve(2 * num_entries);
bool need_slow_path = false;
bool found_dup = false;
for (int i = start; i < num_entries; ++i) {
// Can use Unchecked here as the start loop already ensured that the arrays are correct
// wrt/ kPointerSize.
ArtMethod* vtable_entry = vtable->GetElementPtrSizeUnchecked<ArtMethod*, kPointerSize>(i);
if (!klass->CanAccessMember(vtable_entry->GetDeclaringClass(),
vtable_entry->GetAccessFlags())) {
continue;
}
ArtMethod* m = vtable_entry->GetInterfaceMethodIfProxy(kPointerSize);
if (dex_file != m->GetDexFile()) {
need_slow_path = true;
break;
}
const dex::MethodId* m_mid = &dex_file->GetMethodId(m->GetDexMethodIndex());
PairType pair = std::make_pair(m_mid->name_idx_.index_, m_mid->proto_idx_.index_);
auto it = seen.find(pair);
if (it != seen.end()) {
found_dup = true;
if (log_warn) {
log_fn(it->second, i);
}
} else {
seen.insert(std::make_pair(pair, i));
}
}
return std::make_pair(need_slow_path, found_dup);
};
std::pair<bool, bool> result = check_fn(/* log_warn= */ false);
if (!result.first) {
if (result.second) {
check_fn(/* log_warn= */ true);
}
return;
}
}
// Need to check across dex files.
struct Entry {
size_t cached_hash = 0;
uint32_t name_len = 0;
const char* name = nullptr;
Signature signature = Signature::NoSignature();
Entry() = default;
Entry(const Entry& other) = default;
Entry& operator=(const Entry& other) = default;
Entry(const DexFile* dex_file, const dex::MethodId& mid)
: name_len(0), // Explicit to enforce ordering with -Werror,-Wreorder-ctor.
// This call writes `name_len` and it is therefore necessary that the
// initializer for `name_len` comes before it, otherwise the value
// from the call would be overwritten by that initializer.
name(dex_file->StringDataAndUtf16LengthByIdx(mid.name_idx_, &name_len)),
signature(dex_file->GetMethodSignature(mid)) {
// The `name_len` has been initialized to the UTF16 length. Calculate length in bytes.
if (name[name_len] != 0) {
name_len += strlen(name + name_len);
}
}
bool operator==(const Entry& other) const {
return name_len == other.name_len &&
memcmp(name, other.name, name_len) == 0 &&
signature == other.signature;
}
};
struct EntryHash {
size_t operator()(const Entry& key) const {
return key.cached_hash;
}
};
HashMap<Entry, int32_t, DefaultMapEmptyFn<Entry, int32_t>, EntryHash> map;
for (int32_t i = 0; i < num_entries; ++i) {
// Can use Unchecked here as the first loop already ensured that the arrays are correct
// wrt/ kPointerSize.
ArtMethod* vtable_entry = vtable->GetElementPtrSizeUnchecked<ArtMethod*, kPointerSize>(i);
// Don't bother if we cannot 'see' the vtable entry (i.e. it is a package-private member
// maybe).
if (!klass->CanAccessMember(vtable_entry->GetDeclaringClass(),
vtable_entry->GetAccessFlags())) {
continue;
}
ArtMethod* m = vtable_entry->GetInterfaceMethodIfProxy(kPointerSize);
const DexFile* dex_file = m->GetDexFile();
const dex::MethodId& mid = dex_file->GetMethodId(m->GetDexMethodIndex());
Entry e(dex_file, mid);
size_t string_hash = std::hash<std::string_view>()(std::string_view(e.name, e.name_len));
size_t sig_hash = std::hash<std::string>()(e.signature.ToString());
e.cached_hash = BaseHashType::HashCombine(BaseHashType::HashCombine(0u, string_hash),
sig_hash);
auto it = map.find(e);
if (it != map.end()) {
log_fn(it->second, i);
} else {
map.insert(std::make_pair(e, i));
}
}
}
void CheckVTableHasNoDuplicates(Thread* self,
Handle<mirror::Class> klass,
PointerSize pointer_size)
REQUIRES_SHARED(Locks::mutator_lock_) {
switch (pointer_size) {
case PointerSize::k64:
CheckVTableHasNoDuplicates<PointerSize::k64>(self, klass);
break;
case PointerSize::k32:
CheckVTableHasNoDuplicates<PointerSize::k32>(self, klass);
break;
}
}
static void CheckVTable(Thread* self, Handle<mirror::Class> klass, PointerSize pointer_size)
REQUIRES_SHARED(Locks::mutator_lock_) {
CheckClassOwnsVTableEntries(self, klass, pointer_size);
CheckVTableHasNoDuplicates(self, klass, pointer_size);
}
} // namespace
void ClassLinker::FillImtFromSuperClass(Handle<mirror::Class> klass,
ArtMethod* unimplemented_method,
ArtMethod* imt_conflict_method,
bool* new_conflict,
ArtMethod** imt) {
DCHECK(klass->HasSuperClass());
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
if (super_class->ShouldHaveImt()) {
ImTable* super_imt = super_class->GetImt(image_pointer_size_);
for (size_t i = 0; i < ImTable::kSize; ++i) {
imt[i] = super_imt->Get(i, image_pointer_size_);
}
} else {
// No imt in the super class, need to reconstruct from the iftable.
ObjPtr<mirror::IfTable> if_table = super_class->GetIfTable();
if (if_table->Count() != 0) {
// Ignore copied methods since we will handle these in LinkInterfaceMethods.
FillIMTFromIfTable(if_table,
unimplemented_method,
imt_conflict_method,
klass.Get(),
/*create_conflict_tables=*/false,
/*ignore_copied_methods=*/true,
/*out*/new_conflict,
/*out*/imt);
}
}
}
class ClassLinker::LinkMethodsHelper {
public:
LinkMethodsHelper(ClassLinker* class_linker,
Handle<mirror::Class> klass,
Thread* self,
Runtime* runtime)
: class_linker_(class_linker),
klass_(klass),
method_alignment_(ArtMethod::Alignment(class_linker->GetImagePointerSize())),
method_size_(ArtMethod::Size(class_linker->GetImagePointerSize())),
self_(self),
stack_(runtime->GetLinearAlloc()->GetArenaPool()),
allocator_(&stack_),
default_translations_(default_translations_initial_buffer_,
kDefaultTranslationsInitialBufferSize,
allocator_.Adapter()),
default_conflict_methods_(allocator_.Adapter()),
overriding_default_conflict_methods_(allocator_.Adapter()),
miranda_methods_(allocator_.Adapter()),
default_methods_(allocator_.Adapter()),
overriding_default_methods_(allocator_.Adapter()),
move_table_(allocator_.Adapter()) {
}
// Links the virtual methods for the given class and records any default methods
// that will need to be updated later.
//
// Arguments:
// * self - The current thread.
// * klass - class, whose vtable will be filled in.
bool LinkVirtualMethods(Thread* self, Handle<mirror::Class> klass)
REQUIRES_SHARED(Locks::mutator_lock_);
// Sets the imt entries and fixes up the vtable for the given class by linking
// all the interface methods.
bool LinkInterfaceMethods(
Thread* self,
Handle<mirror::Class> klass,
Runtime* runtime,
bool* out_new_conflict,
ArtMethod** out_imt)
REQUIRES_SHARED(Locks::mutator_lock_);
private:
ArtMethod* FindOrCreateImplementationMethod(
ArtMethod* interface_method,
MethodNameAndSignatureComparator& interface_name_comparator,
ArtMethod* vtable_impl)
REQUIRES_SHARED(Locks::mutator_lock_);
ArtMethod* GetOrCreateMirandaMethod(ArtMethod* interface_method,
MethodNameAndSignatureComparator& interface_name_comparator)
REQUIRES_SHARED(Locks::mutator_lock_);
bool HasNewVirtuals() const {
return !(miranda_methods_.empty() &&
default_methods_.empty() &&
overriding_default_methods_.empty() &&
overriding_default_conflict_methods_.empty() &&
default_conflict_methods_.empty());
}
void ReallocMethods() REQUIRES_SHARED(Locks::mutator_lock_);
ObjPtr<mirror::PointerArray> UpdateVtable(Handle<mirror::PointerArray> old_vtable)
REQUIRES_SHARED(Locks::mutator_lock_);
void UpdateIfTable(Handle<mirror::IfTable> iftable) REQUIRES_SHARED(Locks::mutator_lock_);
void UpdateIMT(ArtMethod** out_imt);
void CheckNoStaleMethodsInDexCache() REQUIRES_SHARED(Locks::mutator_lock_) {
if (kIsDebugBuild) {
PointerSize pointer_size = class_linker_->GetImagePointerSize();
// Check that there are no stale methods are in the dex cache array.
ObjPtr<mirror::DexCache> dex_cache = klass_->GetDexCache();
auto* resolved_methods = dex_cache->GetResolvedMethods();
size_t num_methods = dex_cache->NumResolvedMethods();
for (size_t i = 0; resolved_methods != nullptr && i < num_methods; ++i) {
auto pair = mirror::DexCache::GetNativePair(resolved_methods, i);
ArtMethod* m = pair.object;
CHECK(move_table_.find(m) == move_table_.end() ||
// The original versions of copied methods will still be present so allow those too.
// Note that if the first check passes this might fail to GetDeclaringClass().
std::find_if(m->GetDeclaringClass()->GetMethods(pointer_size).begin(),
m->GetDeclaringClass()->GetMethods(pointer_size).end(),
[m] (ArtMethod& meth) {
return &meth == m;
}) != m->GetDeclaringClass()->GetMethods(pointer_size).end())
<< "Obsolete method " << m->PrettyMethod() << " is in dex cache!";
}
}
}
void ClobberOldMethods(LengthPrefixedArray<ArtMethod>* old_methods,
LengthPrefixedArray<ArtMethod>* methods) {
if (kIsDebugBuild) {
CHECK(methods != nullptr);
// Put some random garbage in old methods to help find stale pointers.
if (methods != old_methods && old_methods != nullptr) {
// Need to make sure the GC is not running since it could be scanning the methods we are
// about to overwrite.
ScopedThreadStateChange tsc(self_, ThreadState::kSuspended);
gc::ScopedGCCriticalSection gcs(self_,
gc::kGcCauseClassLinker,
gc::kCollectorTypeClassLinker);
const size_t old_size = LengthPrefixedArray<ArtMethod>::ComputeSize(old_methods->size(),
method_size_,
method_alignment_);
memset(old_methods, 0xFEu, old_size);
}
}
}
size_t NumberOfNewVirtuals() const {
return miranda_methods_.size() +
default_methods_.size() +
overriding_default_conflict_methods_.size() +
overriding_default_methods_.size() +
default_conflict_methods_.size();
}
bool FillTables() REQUIRES_SHARED(Locks::mutator_lock_) {
return !klass_->IsInterface();
}
void LogNewVirtuals() const REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(!klass_->IsInterface() || (default_methods_.empty() && miranda_methods_.empty()))
<< "Interfaces should only have default-conflict methods appended to them.";
VLOG(class_linker) << mirror::Class::PrettyClass(klass_.Get()) << ": miranda_methods="
<< miranda_methods_.size()
<< " default_methods=" << default_methods_.size()
<< " overriding_default_methods=" << overriding_default_methods_.size()
<< " default_conflict_methods=" << default_conflict_methods_.size()
<< " overriding_default_conflict_methods="
<< overriding_default_conflict_methods_.size();
}
ClassLinker* class_linker_;
Handle<mirror::Class> klass_;
size_t method_alignment_;
size_t method_size_;
Thread* const self_;
// These are allocated on the heap to begin, we then transfer to linear alloc when we re-create
// the virtual methods array.
// Need to use low 4GB arenas for compiler or else the pointers wont fit in 32 bit method array
// during cross compilation.
// Use the linear alloc pool since this one is in the low 4gb for the compiler.
ArenaStack stack_;
ScopedArenaAllocator allocator_;
// A map from vtable indexes to the method they need to be updated to point to. Used because we
// need to have default methods be in the virtuals array of each class but we don't set that up
// until LinkInterfaceMethods.
// The default_translations map is keyed on the vtable index that needs to be updated. We use
// this map because if we override a default method with another default method we need to
// update the vtable to point to the new method. Unfortunately since we copy the ArtMethod* we
// cannot just do a simple scan, we therefore store the vtable index's that might need to be
// updated with the method they will turn into.
// TODO This whole default_translations thing is very dirty. There should be a better way.
using DefaultTranslationsHashMap = ScopedArenaHashMap<size_t, ClassLinker::MethodTranslation>;
// Avoid large allocation for a few translations.
// Keep the initial buffer on the stack to avoid arena allocations
// if there are no special cases (the first arena allocation is costly).
static constexpr size_t kDefaultTranslationsInitialBufferSize = 8;
DefaultTranslationsHashMap::value_type default_translations_initial_buffer_[
kDefaultTranslationsInitialBufferSize];
DefaultTranslationsHashMap default_translations_;
ScopedArenaVector<ArtMethod*> default_conflict_methods_;
ScopedArenaVector<ArtMethod*> overriding_default_conflict_methods_;
ScopedArenaVector<ArtMethod*> miranda_methods_;
ScopedArenaVector<ArtMethod*> default_methods_;
ScopedArenaVector<ArtMethod*> overriding_default_methods_;
ScopedArenaUnorderedMap<ArtMethod*, ArtMethod*> move_table_;
};
ArtMethod* ClassLinker::LinkMethodsHelper::FindOrCreateImplementationMethod(
ArtMethod* interface_method,
MethodNameAndSignatureComparator& interface_name_comparator,
ArtMethod* vtable_impl) {
ArtMethod* current_method = nullptr;
switch (class_linker_->FindDefaultMethodImplementation(self_,
interface_method,
klass_,
/*out*/&current_method)) {
case DefaultMethodSearchResult::kDefaultConflict: {
// Default method conflict.
DCHECK(current_method == nullptr);
ArtMethod* default_conflict_method = nullptr;
if (vtable_impl != nullptr && vtable_impl->IsDefaultConflicting()) {
// We can reuse the method from the superclass, don't bother adding it to virtuals.
default_conflict_method = vtable_impl;
} else {
// See if we already have a conflict method for this method.
ArtMethod* preexisting_conflict = FindSameNameAndSignature(
interface_name_comparator,
default_conflict_methods_,
overriding_default_conflict_methods_);
if (LIKELY(preexisting_conflict != nullptr)) {
// We already have another conflict we can reuse.
default_conflict_method = preexisting_conflict;
} else {
// Note that we do this even if we are an interface since we need to create this and
// cannot reuse another classes.
// Create a new conflict method for this to use.
default_conflict_method = reinterpret_cast<ArtMethod*>(allocator_.Alloc(method_size_));
new(default_conflict_method) ArtMethod(interface_method,
class_linker_->GetImagePointerSize());
if (vtable_impl == nullptr) {
// Save the conflict method. We need to add it to the vtable.
default_conflict_methods_.push_back(default_conflict_method);
} else {
// Save the conflict method but it is already in the vtable.
overriding_default_conflict_methods_.push_back(default_conflict_method);
}
}
}
current_method = default_conflict_method;
break;
} // case kDefaultConflict
case DefaultMethodSearchResult::kDefaultFound: {
DCHECK(current_method != nullptr);
// Found a default method.
if (vtable_impl != nullptr &&
current_method->GetDeclaringClass() == vtable_impl->GetDeclaringClass()) {
// We found a default method but it was the same one we already have from our
// superclass. Don't bother adding it to our vtable again.
current_method = vtable_impl;
} else if (LIKELY(FillTables())) {
// Interfaces don't need to copy default methods since they don't have vtables.
// Only record this default method if it is new to save space.
// TODO It might be worthwhile to copy default methods on interfaces anyway since it
// would make lookup for interface super much faster. (We would only need to scan
// the iftable to find if there is a NSME or AME.)
ArtMethod* old = FindSameNameAndSignature(interface_name_comparator,
default_methods_,
overriding_default_methods_);
if (old == nullptr) {
// We found a default method implementation and there were no conflicts.
if (vtable_impl == nullptr) {
// Save the default method. We need to add it to the vtable.
default_methods_.push_back(current_method);
} else {
// Save the default method but it is already in the vtable.
overriding_default_methods_.push_back(current_method);
}
} else {
CHECK(old == current_method) << "Multiple default implementations selected!";
}
}
break;
} // case kDefaultFound
case DefaultMethodSearchResult::kAbstractFound: {
DCHECK(current_method == nullptr);
// Abstract method masks all defaults.
if (vtable_impl != nullptr &&
vtable_impl->IsAbstract() &&
!vtable_impl->IsDefaultConflicting()) {
// We need to make this an abstract method but the version in the vtable already is so
// don't do anything.
current_method = vtable_impl;
}
break;
} // case kAbstractFound
}
return current_method;
}
ArtMethod* ClassLinker::LinkMethodsHelper::GetOrCreateMirandaMethod(
ArtMethod* interface_method,
MethodNameAndSignatureComparator& interface_name_comparator) {
// Find out if there is already a miranda method we can use.
ArtMethod* miranda_method = FindSameNameAndSignature(interface_name_comparator,
miranda_methods_);
if (miranda_method == nullptr) {
DCHECK(interface_method->IsAbstract()) << interface_method->PrettyMethod();
miranda_method = reinterpret_cast<ArtMethod*>(allocator_.Alloc(method_size_));
CHECK(miranda_method != nullptr);
// Point the interface table at a phantom slot.
new(miranda_method) ArtMethod(interface_method, class_linker_->GetImagePointerSize());
miranda_methods_.push_back(miranda_method);
}
return miranda_method;
}
void ClassLinker::LinkMethodsHelper::ReallocMethods() {
LogNewVirtuals();
const size_t old_method_count = klass_->NumMethods();
const size_t new_method_count = old_method_count + NumberOfNewVirtuals();
DCHECK_NE(old_method_count, new_method_count);
// Attempt to realloc to save RAM if possible.
LengthPrefixedArray<ArtMethod>* old_methods = klass_->GetMethodsPtr();
// The Realloced virtual methods aren't visible from the class roots, so there is no issue
// where GCs could attempt to mark stale pointers due to memcpy. And since we overwrite the
// realloced memory with out->CopyFrom, we are guaranteed to have objects in the to space since
// CopyFrom has internal read barriers.
//
// TODO We should maybe move some of this into mirror::Class or at least into another method.
const size_t old_size = LengthPrefixedArray<ArtMethod>::ComputeSize(old_method_count,
method_size_,
method_alignment_);
const size_t new_size = LengthPrefixedArray<ArtMethod>::ComputeSize(new_method_count,
method_size_,
method_alignment_);
const size_t old_methods_ptr_size = (old_methods != nullptr) ? old_size : 0;
auto* methods = reinterpret_cast<LengthPrefixedArray<ArtMethod>*>(
class_linker_->GetAllocatorForClassLoader(klass_->GetClassLoader())->Realloc(
self_, old_methods, old_methods_ptr_size, new_size));
CHECK(methods != nullptr); // Native allocation failure aborts.
PointerSize pointer_size = class_linker_->GetImagePointerSize();
if (methods != old_methods) {
// Maps from heap allocated miranda method to linear alloc miranda method.
StrideIterator<ArtMethod> out = methods->begin(method_size_, method_alignment_);
// Copy over the old methods.
for (auto& m : klass_->GetMethods(pointer_size)) {
move_table_.emplace(&m, &*out);
// The CopyFrom is only necessary to not miss read barriers since Realloc won't do read
// barriers when it copies.
out->CopyFrom(&m, pointer_size);
++out;
}
}
StrideIterator<ArtMethod> out(methods->begin(method_size_, method_alignment_) + old_method_count);
// Copy over miranda methods before copying vtable since CopyOf may cause thread suspension and
// we want the roots of the miranda methods to get visited.
for (size_t i = 0; i < miranda_methods_.size(); ++i) {
ArtMethod* mir_method = miranda_methods_[i];
ArtMethod& new_method = *out;
new_method.CopyFrom(mir_method, pointer_size);
uint32_t access_flags = new_method.GetAccessFlags();
DCHECK_EQ(access_flags & kAccIntrinsic, 0u) << "Miranda method should not be an intrinsic!";
DCHECK_EQ(access_flags & kAccDefault, 0u) << "Miranda method should not be a default method!";
DCHECK_NE(access_flags & kAccAbstract, 0u) << "Miranda method should be abstract!";
new_method.SetAccessFlags(access_flags | kAccCopied);
move_table_.emplace(mir_method, &new_method);
// Update the entry in the method array, as the array will be used for future lookups,
// where thread suspension is allowed.
// As such, the array should not contain locally allocated ArtMethod, otherwise the GC
// would not see them.
miranda_methods_[i] = &new_method;
++out;
}
// We need to copy the default methods into our own method table since the runtime requires that
// every method on a class's vtable be in that respective class's virtual method table.
// NOTE This means that two classes might have the same implementation of a method from the same
// interface but will have different ArtMethod*s for them. This also means we cannot compare a
// default method found on a class with one found on the declaring interface directly and must
// look at the declaring class to determine if they are the same.
for (ScopedArenaVector<ArtMethod*>* methods_vec : {&default_methods_,
&overriding_default_methods_}) {
for (size_t i = 0; i < methods_vec->size(); ++i) {
ArtMethod* def_method = (*methods_vec)[i];
ArtMethod& new_method = *out;
new_method.CopyFrom(def_method, pointer_size);
// Clear the kAccSkipAccessChecks flag if it is present. Since this class hasn't been
// verified yet it shouldn't have methods that are skipping access checks.
// TODO This is rather arbitrary. We should maybe support classes where only some of its
// methods are skip_access_checks.
DCHECK_EQ(new_method.GetAccessFlags() & kAccNative, 0u);
constexpr uint32_t kSetFlags = kAccDefault | kAccCopied;
constexpr uint32_t kMaskFlags = ~kAccSkipAccessChecks;
new_method.SetAccessFlags((new_method.GetAccessFlags() | kSetFlags) & kMaskFlags);
move_table_.emplace(def_method, &new_method);
// Update the entry in the method array, as the array will be used for future lookups,
// where thread suspension is allowed.
// As such, the array should not contain locally allocated ArtMethod, otherwise the GC
// would not see them.
(*methods_vec)[i] = &new_method;
++out;
}
}
for (ScopedArenaVector<ArtMethod*>* methods_vec : {&default_conflict_methods_,
&overriding_default_conflict_methods_}) {
for (size_t i = 0; i < methods_vec->size(); ++i) {
ArtMethod* conf_method = (*methods_vec)[i];
ArtMethod& new_method = *out;
new_method.CopyFrom(conf_method, pointer_size);
// This is a type of default method (there are default method impls, just a conflict) so
// mark this as a default. We use the `kAccAbstract` flag to distinguish it from invokable
// copied default method without using a separate access flag but the default conflicting
// method is technically not abstract and ArtMethod::IsAbstract() shall return false.
// Also clear the kAccSkipAccessChecks bit since this class hasn't been verified yet it
// shouldn't have methods that are skipping access checks. Also clear potential
// kAccSingleImplementation to avoid CHA trying to inline the default method.
uint32_t access_flags = new_method.GetAccessFlags();
DCHECK_EQ(access_flags & kAccNative, 0u);
DCHECK_EQ(access_flags & kAccIntrinsic, 0u);
constexpr uint32_t kSetFlags = kAccDefault | kAccAbstract | kAccCopied;
constexpr uint32_t kMaskFlags = ~(kAccSkipAccessChecks | kAccSingleImplementation);
new_method.SetAccessFlags((access_flags | kSetFlags) & kMaskFlags);
DCHECK(new_method.IsDefaultConflicting());
DCHECK(!new_method.IsAbstract());
// The actual method might or might not be marked abstract since we just copied it from a
// (possibly default) interface method. We need to set it entry point to be the bridge so
// that the compiler will not invoke the implementation of whatever method we copied from.
EnsureThrowsInvocationError(class_linker_, &new_method);
move_table_.emplace(conf_method, &new_method);
// Update the entry in the method array, as the array will be used for future lookups,
// where thread suspension is allowed.
// As such, the array should not contain locally allocated ArtMethod, otherwise the GC
// would not see them.
(*methods_vec)[i] = &new_method;
++out;
}
}
methods->SetSize(new_method_count);
class_linker_->UpdateClassMethods(klass_.Get(), methods);
}
ObjPtr<mirror::PointerArray> ClassLinker::LinkMethodsHelper::UpdateVtable(
Handle<mirror::PointerArray> old_vtable) {
// Update the vtable to the new method structures. We can skip this for interfaces since they
// do not have vtables.
const size_t old_vtable_count = old_vtable->GetLength();
const size_t new_vtable_count = old_vtable_count +
miranda_methods_.size() +
default_methods_.size() +
default_conflict_methods_.size();
ObjPtr<mirror::PointerArray> vtable = ObjPtr<mirror::PointerArray>::DownCast(
mirror::Array::CopyOf(old_vtable, self_, new_vtable_count));
if (UNLIKELY(vtable == nullptr)) {
self_->AssertPendingOOMException();
return nullptr;
}
size_t vtable_pos = old_vtable_count;
PointerSize pointer_size = class_linker_->GetImagePointerSize();
// Update all the newly copied method's indexes so they denote their placement in the vtable.
for (const ScopedArenaVector<ArtMethod*>& methods_vec : {default_methods_,
default_conflict_methods_,
miranda_methods_}) {
// These are the functions that are not already in the vtable!
for (ArtMethod* new_vtable_method : methods_vec) {
// Leave the declaring class alone the method's dex_code_item_offset_ and dex_method_index_
// fields are references into the dex file the method was defined in. Since the ArtMethod
// does not store that information it uses declaring_class_->dex_cache_.
new_vtable_method->SetMethodIndex(0xFFFF & vtable_pos);
vtable->SetElementPtrSize(vtable_pos, new_vtable_method, pointer_size);
++vtable_pos;
}
}
DCHECK_EQ(vtable_pos, new_vtable_count);
// Update old vtable methods. We use the `default_translations_` map to figure out what each
// vtable entry should be updated to, if they need to be at all.
for (size_t i = 0; i < old_vtable_count; ++i) {
ArtMethod* translated_method = vtable->GetElementPtrSize<ArtMethod*>(i, pointer_size);
// Try and find what we need to change this method to.
auto translation_it = default_translations_.find(i);
if (translation_it != default_translations_.end()) {
if (translation_it->second.IsInConflict()) {
// Find which conflict method we are to use for this method.
MethodNameAndSignatureComparator old_method_comparator(
translated_method->GetInterfaceMethodIfProxy(pointer_size));
// We only need to look through overriding_default_conflict_methods since this is an
// overridden method we are fixing up here.
ArtMethod* new_conflict_method = FindSameNameAndSignature(
old_method_comparator, overriding_default_conflict_methods_);
CHECK(new_conflict_method != nullptr) << "Expected a conflict method!";
translated_method = new_conflict_method;
} else if (translation_it->second.IsAbstract()) {
// Find which miranda method we are to use for this method.
MethodNameAndSignatureComparator old_method_comparator(
translated_method->GetInterfaceMethodIfProxy(pointer_size));
ArtMethod* miranda_method = FindSameNameAndSignature(old_method_comparator,
miranda_methods_);
DCHECK(miranda_method != nullptr);
translated_method = miranda_method;
} else {
// Normal default method (changed from an older default or abstract interface method).
DCHECK(translation_it->second.IsTranslation());
translated_method = translation_it->second.GetTranslation();
auto it = move_table_.find(translated_method);
DCHECK(it != move_table_.end());
translated_method = it->second;
}
} else {
auto it = move_table_.find(translated_method);
translated_method = (it != move_table_.end()) ? it->second : nullptr;
}
if (translated_method != nullptr) {
// Make sure the new_methods index is set.
if (translated_method->GetMethodIndexDuringLinking() != i) {
if (kIsDebugBuild) {
auto* methods = klass_->GetMethodsPtr();
CHECK_LE(reinterpret_cast<uintptr_t>(&*methods->begin(method_size_, method_alignment_)),
reinterpret_cast<uintptr_t>(translated_method));
CHECK_LT(reinterpret_cast<uintptr_t>(translated_method),
reinterpret_cast<uintptr_t>(&*methods->end(method_size_, method_alignment_)));
}
translated_method->SetMethodIndex(0xFFFF & i);
}
vtable->SetElementPtrSize(i, translated_method, pointer_size);
}
}
klass_->SetVTable(vtable);
return vtable;
}
void ClassLinker::LinkMethodsHelper::UpdateIfTable(Handle<mirror::IfTable> iftable) {
PointerSize pointer_size = class_linker_->GetImagePointerSize();
const size_t ifcount = klass_->GetIfTableCount();
// Go fix up all the stale iftable pointers.
for (size_t i = 0; i < ifcount; ++i) {
for (size_t j = 0, count = iftable->GetMethodArrayCount(i); j < count; ++j) {
ObjPtr<mirror::PointerArray> method_array = iftable->GetMethodArray(i);
ArtMethod* m = method_array->GetElementPtrSize<ArtMethod*>(j, pointer_size);
DCHECK(m != nullptr) << klass_->PrettyClass();
auto it = move_table_.find(m);
if (it != move_table_.end()) {
auto* new_m = it->second;
DCHECK(new_m != nullptr) << klass_->PrettyClass();
method_array->SetElementPtrSize(j, new_m, pointer_size);
}
}
}
}
void ClassLinker::LinkMethodsHelper::UpdateIMT(ArtMethod** out_imt) {
// Fix up IMT next.
for (size_t i = 0; i < ImTable::kSize; ++i) {
auto it = move_table_.find(out_imt[i]);
if (it != move_table_.end()) {
out_imt[i] = it->second;
}
}
}
bool ClassLinker::LinkMethodsHelper::LinkVirtualMethods(
Thread* self,
Handle<mirror::Class> klass) {
const PointerSize image_pointer_size = class_linker_->GetImagePointerSize();
const size_t num_virtual_methods = klass->NumVirtualMethods();
if (klass->IsInterface()) {
// No vtable.
if (!IsUint<16>(num_virtual_methods)) {
ThrowClassFormatError(klass.Get(), "Too many methods on interface: %zu", num_virtual_methods);
return false;
}
bool has_defaults = false;
// Assign each method an IMT index and set the default flag.
for (size_t i = 0; i < num_virtual_methods; ++i) {
ArtMethod* m = klass->GetVirtualMethodDuringLinking(i, image_pointer_size);
m->SetMethodIndex(i);
if (!m->IsAbstract()) {
// If the dex file does not support default methods, throw ClassFormatError.
// This check is necessary to protect from odd cases, such as native default
// methods, that the dex file verifier permits for old dex file versions. b/157170505
// FIXME: This should be `if (!m->GetDexFile()->SupportsDefaultMethods())` but we're
// currently running CTS tests for default methods with dex file version 035 which
// does not support default methods. So, we limit this to native methods. b/157718952
if (m->IsNative()) {
DCHECK(!m->GetDexFile()->SupportsDefaultMethods());
ThrowClassFormatError(klass.Get(),
"Dex file does not support default method '%s'",
m->PrettyMethod().c_str());
return false;
}
m->SetAccessFlags(m->GetAccessFlags() | kAccDefault);
has_defaults = true;
}
}
// Mark that we have default methods so that we won't need to scan the virtual_methods_ array
// during initialization. This is a performance optimization. We could simply traverse the
// virtual_methods_ array again during initialization.
if (has_defaults) {
klass->SetHasDefaultMethods();
}
return true;
} else if (klass->HasSuperClass()) {
const size_t super_vtable_length = klass->GetSuperClass()->GetVTableLength();
const size_t max_count = num_virtual_methods + super_vtable_length;
StackHandleScope<3> hs(self);
Handle<mirror::Class> super_class(hs.NewHandle(klass->GetSuperClass()));
MutableHandle<mirror::PointerArray> vtable;
if (super_class->ShouldHaveEmbeddedVTable()) {
vtable = hs.NewHandle(class_linker_->AllocPointerArray(self, max_count));
if (UNLIKELY(vtable == nullptr)) {
self->AssertPendingOOMException();
return false;
}
for (size_t i = 0; i < super_vtable_length; i++) {
vtable->SetElementPtrSize(
i, super_class->GetEmbeddedVTableEntry(i, image_pointer_size), image_pointer_size);
}
// We might need to change vtable if we have new virtual methods or new interfaces (since that
// might give us new default methods). If no new interfaces then we can skip the rest since
// the class cannot override any of the super-class's methods. This is required for
// correctness since without it we might not update overridden default method vtable entries
// correctly.
if (num_virtual_methods == 0 && super_class->GetIfTableCount() == klass->GetIfTableCount()) {
klass->SetVTable(vtable.Get());
return true;
}
} else {
DCHECK(super_class->IsAbstract() && !super_class->IsArrayClass());
Handle<mirror::PointerArray> super_vtable = hs.NewHandle(super_class->GetVTable());
CHECK(super_vtable != nullptr) << super_class->PrettyClass();
// We might need to change vtable if we have new virtual methods or new interfaces (since that
// might give us new default methods). See comment above.
if (num_virtual_methods == 0 && super_class->GetIfTableCount() == klass->GetIfTableCount()) {
klass->SetVTable(super_vtable.Get());
return true;
}
vtable = hs.NewHandle(ObjPtr<mirror::PointerArray>::DownCast(
mirror::Array::CopyOf(super_vtable, self, max_count)));
if (UNLIKELY(vtable == nullptr)) {
self->AssertPendingOOMException();
return false;
}
}
// How the algorithm works:
// 1. Populate hash table by adding num_virtual_methods from klass. The values in the hash
// table are: invalid_index for unused slots, index super_vtable_length + i for a virtual
// method which has not been matched to a vtable method, and j if the virtual method at the
// index overrode the super virtual method at index j.
// 2. Loop through super virtual methods, if they overwrite, update hash table to j
// (j < super_vtable_length) to avoid redundant checks. (TODO maybe use this info for reducing
// the need for the initial vtable which we later shrink back down).
// 3. Add non overridden methods to the end of the vtable.
static constexpr size_t kMaxStackHash = 250;
// + 1 so that even if we only have new default methods we will still be able to use this hash
// table (i.e. it will never have 0 size).
const size_t hash_table_size = num_virtual_methods * 3 + 1;
uint32_t* hash_table_ptr;
std::unique_ptr<uint32_t[]> hash_heap_storage;
if (hash_table_size <= kMaxStackHash) {
hash_table_ptr = reinterpret_cast<uint32_t*>(
alloca(hash_table_size * sizeof(*hash_table_ptr)));
} else {
hash_heap_storage.reset(new uint32_t[hash_table_size]);
hash_table_ptr = hash_heap_storage.get();
}
LinkVirtualHashTable hash_table(klass, hash_table_size, hash_table_ptr, image_pointer_size);
// Add virtual methods to the hash table.
for (size_t i = 0; i < num_virtual_methods; ++i) {
DCHECK(klass->GetVirtualMethodDuringLinking(
i, image_pointer_size)->GetDeclaringClass() != nullptr);
hash_table.Add(i);
}
// Loop through each super vtable method and see if they are overridden by a method we added to
// the hash table.
for (size_t j = 0; j < super_vtable_length; ++j) {
// Search the hash table to see if we are overridden by any method.
ArtMethod* super_method = vtable->GetElementPtrSize<ArtMethod*>(j, image_pointer_size);
if (!klass->CanAccessMember(super_method->GetDeclaringClass(),
super_method->GetAccessFlags())) {
// Continue on to the next method since this one is package private
// and cannot be overridden. Before Android 4.1, the package-private
// method super_method might have been incorrectly overridden.
continue;
}
MethodNameAndSignatureComparator super_method_name_comparator(
super_method->GetInterfaceMethodIfProxy(image_pointer_size));
// We remove the method so that subsequent lookups will be faster by making the hash-map
// smaller as we go on.
uint32_t hash = (j < mirror::Object::kVTableLength)
? class_linker_->object_virtual_method_hashes_[j]
: ComputeModifiedUtf8Hash(super_method_name_comparator.GetNameView());
uint32_t hash_index = hash_table.FindAndRemove(&super_method_name_comparator, hash);
if (hash_index != hash_table.GetNotFoundIndex()) {
ArtMethod* virtual_method = klass->GetVirtualMethodDuringLinking(
hash_index, image_pointer_size);
if (super_method->IsFinal()) {
ThrowLinkageError(klass.Get(), "Method %s overrides final method in class %s",
virtual_method->PrettyMethod().c_str(),
super_method->GetDeclaringClassDescriptor());
return false;
}
vtable->SetElementPtrSize(j, virtual_method, image_pointer_size);
virtual_method->SetMethodIndex(j);
} else if (super_method->IsOverridableByDefaultMethod()) {
// We didn't directly override this method but we might through default methods...
// Check for default method update.
ArtMethod* default_method = nullptr;
switch (class_linker_->FindDefaultMethodImplementation(self,
super_method,
klass,
/*out*/&default_method)) {
case DefaultMethodSearchResult::kDefaultConflict: {
// A conflict was found looking for default methods. Note this (assuming it wasn't
// pre-existing) in the translations map.
if (UNLIKELY(!super_method->IsDefaultConflicting())) {
// Don't generate another conflict method to reduce memory use as an optimization.
default_translations_.insert(
{j, ClassLinker::MethodTranslation::CreateConflictingMethod()});
}
break;
}
case DefaultMethodSearchResult::kAbstractFound: {
// No conflict but method is abstract.
// We note that this vtable entry must be made abstract.
if (UNLIKELY(!super_method->IsAbstract())) {
default_translations_.insert(
{j, ClassLinker::MethodTranslation::CreateAbstractMethod()});
}
break;
}
case DefaultMethodSearchResult::kDefaultFound: {
if (UNLIKELY(super_method->IsDefaultConflicting() ||
default_method->GetDeclaringClass() != super_method->GetDeclaringClass())) {
// Found a default method implementation that is new.
// TODO Refactor this add default methods to virtuals here and not in
// LinkInterfaceMethods maybe.
// The problem is default methods might override previously present
// default-method or miranda-method vtable entries from the superclass.
// Unfortunately we need these to be entries in this class's virtuals. We do not
// give these entries there until LinkInterfaceMethods so we pass this map around
// to let it know which vtable entries need to be updated.
// Make a note that vtable entry j must be updated, store what it needs to be updated
// to. We will allocate a virtual method slot in LinkInterfaceMethods and fix it up
// then.
default_translations_.insert(
{j, ClassLinker::MethodTranslation::CreateTranslatedMethod(default_method)});
VLOG(class_linker) << "Method " << super_method->PrettyMethod()
<< " overridden by default "
<< default_method->PrettyMethod()
<< " in " << mirror::Class::PrettyClass(klass.Get());
}
break;
}
}
}
}
size_t actual_count = super_vtable_length;
// Add the non-overridden methods at the end.
for (size_t i = 0; i < num_virtual_methods; ++i) {
ArtMethod* local_method = klass->GetVirtualMethodDuringLinking(i, image_pointer_size);
size_t method_idx = local_method->GetMethodIndexDuringLinking();
if (method_idx < super_vtable_length &&
local_method == vtable->GetElementPtrSize<ArtMethod*>(method_idx, image_pointer_size)) {
continue;
}
vtable->SetElementPtrSize(actual_count, local_method, image_pointer_size);
local_method->SetMethodIndex(actual_count);
++actual_count;
}
if (!IsUint<16>(actual_count)) {
ThrowClassFormatError(klass.Get(), "Too many methods defined on class: %zd", actual_count);
return false;
}
// Shrink vtable if possible
CHECK_LE(actual_count, max_count);
if (actual_count < max_count) {
vtable.Assign(ObjPtr<mirror::PointerArray>::DownCast(
mirror::Array::CopyOf(vtable, self, actual_count)));
if (UNLIKELY(vtable == nullptr)) {
self->AssertPendingOOMException();
return false;
}
}
klass->SetVTable(vtable.Get());
} else {
CHECK_EQ(klass.Get(), GetClassRoot<mirror::Object>(class_linker_));
if (!IsUint<16>(num_virtual_methods)) {
ThrowClassFormatError(klass.Get(), "Too many methods: %d",
static_cast<int>(num_virtual_methods));
return false;
}
ObjPtr<mirror::PointerArray> vtable =
class_linker_->AllocPointerArray(self, num_virtual_methods);
if (UNLIKELY(vtable == nullptr)) {
self->AssertPendingOOMException();
return false;
}
for (size_t i = 0; i < num_virtual_methods; ++i) {
ArtMethod* virtual_method = klass->GetVirtualMethodDuringLinking(i, image_pointer_size);
vtable->SetElementPtrSize(i, virtual_method, image_pointer_size);
virtual_method->SetMethodIndex(i & 0xFFFF);
}
klass->SetVTable(vtable);
InitializeObjectVirtualMethodHashes(
klass.Get(),
image_pointer_size,
ArrayRef<uint32_t>(class_linker_->object_virtual_method_hashes_));
}
return true;
}
// TODO This method needs to be split up into several smaller methods.
bool ClassLinker::LinkMethodsHelper::LinkInterfaceMethods(
Thread* self,
Handle<mirror::Class> klass,
Runtime* runtime,
bool* out_new_conflict,
ArtMethod** out_imt) {
const PointerSize image_pointer_size = class_linker_->GetImagePointerSize();
StackHandleScope<3> hs(self);
const bool is_interface = klass->IsInterface();
const bool has_superclass = klass->HasSuperClass();
const bool fill_tables = !is_interface;
const size_t super_ifcount = has_superclass ? klass->GetSuperClass()->GetIfTableCount() : 0U;
const size_t ifcount = klass->GetIfTableCount();
Handle<mirror::IfTable> iftable(hs.NewHandle(klass->GetIfTable()));
MutableHandle<mirror::PointerArray> vtable(hs.NewHandle(klass->GetVTableDuringLinking()));
ArtMethod* const unimplemented_method = runtime->GetImtUnimplementedMethod();
ArtMethod* const imt_conflict_method = runtime->GetImtConflictMethod();
// Copy the IMT from the super class if possible.
const bool extend_super_iftable = has_superclass;
if (has_superclass && fill_tables) {
class_linker_->FillImtFromSuperClass(klass,
unimplemented_method,
imt_conflict_method,
out_new_conflict,
out_imt);
}
// Allocate method arrays before since we don't want miss visiting miranda method roots due to
// thread suspension.
if (fill_tables) {
if (!class_linker_->AllocateIfTableMethodArrays(self, klass, iftable)) {
return false;
}
}
auto* old_cause = self->StartAssertNoThreadSuspension(
"Copying ArtMethods for LinkInterfaceMethods");
// Going in reverse to ensure that we will hit abstract methods that override defaults before the
// defaults. This means we don't need to do any trickery when creating the Miranda methods, since
// they will already be null. This has the additional benefit that the declarer of a miranda
// method will actually declare an abstract method.
for (size_t i = ifcount; i != 0u; ) {
--i;
DCHECK_LT(i, ifcount);
size_t num_methods = iftable->GetInterface(i)->NumDeclaredVirtualMethods();
if (num_methods > 0) {
StackHandleScope<2> hs2(self);
const bool is_super = i < super_ifcount;
const bool super_interface = is_super && extend_super_iftable;
// We don't actually create or fill these tables for interfaces, we just copy some methods for
// conflict methods. Just set this as nullptr in those cases.
Handle<mirror::PointerArray> method_array(fill_tables
? hs2.NewHandle(iftable->GetMethodArray(i))
: hs2.NewHandle<mirror::PointerArray>(nullptr));
ArraySlice<ArtMethod> input_virtual_methods;
ScopedNullHandle<mirror::PointerArray> null_handle;
Handle<mirror::PointerArray> input_vtable_array(null_handle);
int32_t input_array_length = 0;
// TODO Cleanup Needed: In the presence of default methods this optimization is rather dirty
// and confusing. Default methods should always look through all the superclasses
// because they are the last choice of an implementation. We get around this by looking
// at the super-classes iftable methods (copied into method_array previously) when we are
// looking for the implementation of a super-interface method but that is rather dirty.
bool using_virtuals;
if (super_interface || is_interface) {
// If we are overwriting a super class interface, try to only virtual methods instead of the
// whole vtable.
using_virtuals = true;
input_virtual_methods = klass->GetDeclaredVirtualMethodsSlice(image_pointer_size);
input_array_length = input_virtual_methods.size();
} else {
// For a new interface, however, we need the whole vtable in case a new
// interface method is implemented in the whole superclass.
using_virtuals = false;
DCHECK(vtable != nullptr);
input_vtable_array = vtable;
input_array_length = input_vtable_array->GetLength();
}
// For each method in interface
for (size_t j = 0; j < num_methods; ++j) {
auto* interface_method = iftable->GetInterface(i)->GetVirtualMethod(j, image_pointer_size);
MethodNameAndSignatureComparator interface_name_comparator(
interface_method->GetInterfaceMethodIfProxy(image_pointer_size));
uint32_t imt_index = interface_method->GetImtIndex();
ArtMethod** imt_ptr = &out_imt[imt_index];
// For each method listed in the interface's method list, find the
// matching method in our class's method list. We want to favor the
// subclass over the superclass, which just requires walking
// back from the end of the vtable. (This only matters if the
// superclass defines a private method and this class redefines
// it -- otherwise it would use the same vtable slot. In .dex files
// those don't end up in the virtual method table, so it shouldn't
// matter which direction we go. We walk it backward anyway.)
//
// To find defaults we need to do the same but also go over interfaces.
bool found_impl = false;
ArtMethod* vtable_impl = nullptr;
for (int32_t k = input_array_length - 1; k >= 0; --k) {
ArtMethod* vtable_method = using_virtuals ?
&input_virtual_methods[k] :
input_vtable_array->GetElementPtrSize<ArtMethod*>(k, image_pointer_size);
ArtMethod* vtable_method_for_name_comparison =
vtable_method->GetInterfaceMethodIfProxy(image_pointer_size);
DCHECK(!vtable_method->IsStatic()) << vtable_method->PrettyMethod();
if (interface_name_comparator.HasSameNameAndSignature(
vtable_method_for_name_comparison)) {
if (!vtable_method->IsAbstract() && !vtable_method->IsPublic()) {
// Must do EndAssertNoThreadSuspension before throw since the throw can cause
// allocations.
self->EndAssertNoThreadSuspension(old_cause);
ThrowIllegalAccessError(klass.Get(),
"Method '%s' implementing interface method '%s' is not public",
vtable_method->PrettyMethod().c_str(),
interface_method->PrettyMethod().c_str());
return false;
} else if (UNLIKELY(vtable_method->IsOverridableByDefaultMethod())) {
// We might have a newer, better, default method for this, so we just skip it. If we
// are still using this we will select it again when scanning for default methods. To
// obviate the need to copy the method again we will make a note that we already found
// a default here.
// TODO This should be much cleaner.
vtable_impl = vtable_method;
break;
} else {
found_impl = true;
if (LIKELY(fill_tables)) {
method_array->SetElementPtrSize(j, vtable_method, image_pointer_size);
// Place method in imt if entry is empty, place conflict otherwise.
class_linker_->SetIMTRef(unimplemented_method,
imt_conflict_method,
vtable_method,
/*out*/out_new_conflict,
/*out*/imt_ptr);
}
break;
}
}
}
// Continue on to the next method if we are done.
if (LIKELY(found_impl)) {
continue;
} else if (LIKELY(super_interface)) {
// Don't look for a default implementation when the super-method is implemented directly
// by the class.
//
// See if we can use the superclasses method and skip searching everything else.
// Note: !found_impl && super_interface
CHECK(extend_super_iftable);
// If this is a super_interface method it is possible we shouldn't override it because a
// superclass could have implemented it directly. We get the method the superclass used
// to implement this to know if we can override it with a default method. Doing this is
// safe since we know that the super_iftable is filled in so we can simply pull it from
// there. We don't bother if this is not a super-classes interface since in that case we
// have scanned the entire vtable anyway and would have found it.
// TODO This is rather dirty but it is faster than searching through the entire vtable
// every time.
ArtMethod* supers_method =
method_array->GetElementPtrSize<ArtMethod*>(j, image_pointer_size);
DCHECK(supers_method != nullptr);
DCHECK(interface_name_comparator.HasSameNameAndSignature(supers_method));
if (LIKELY(!supers_method->IsOverridableByDefaultMethod())) {
// The method is not overridable by a default method (i.e. it is directly implemented
// in some class). Therefore move onto the next interface method.
continue;
} else {
// If the super-classes method is override-able by a default method we need to keep
// track of it since though it is override-able it is not guaranteed to be 'overridden'.
// If it turns out not to be overridden and we did not keep track of it we might add it
// to the vtable twice, causing corruption (vtable entries having inconsistent and
// illegal states, incorrect vtable size, and incorrect or inconsistent iftable entries)
// in this class and any subclasses.
DCHECK(vtable_impl == nullptr || vtable_impl == supers_method)
<< "vtable_impl was " << ArtMethod::PrettyMethod(vtable_impl)
<< " and not 'nullptr' or "
<< supers_method->PrettyMethod()
<< " as expected. IFTable appears to be corrupt!";
vtable_impl = supers_method;
}
}
// If we haven't found it yet we should search through the interfaces for default methods.
ArtMethod* current_method = FindOrCreateImplementationMethod(
interface_method, interface_name_comparator, vtable_impl);
if (LIKELY(fill_tables)) {
if (current_method == nullptr && !super_interface) {
// We could not find an implementation for this method and since it is a brand new
// interface we searched the entire vtable (and all default methods) for an
// implementation but couldn't find one. We therefore need to make a miranda method.
current_method = GetOrCreateMirandaMethod(interface_method,
interface_name_comparator);
}
if (current_method != nullptr) {
// We found a default method implementation. Record it in the iftable and IMT.
method_array->SetElementPtrSize(j, current_method, image_pointer_size);
class_linker_->SetIMTRef(unimplemented_method,
imt_conflict_method,
current_method,
/*out*/out_new_conflict,
/*out*/imt_ptr);
}
}
} // For each method in interface end.
} // if (num_methods > 0)
} // For each interface.
// TODO don't extend virtuals of interface unless necessary (when is it?).
if (HasNewVirtuals()) {
LengthPrefixedArray<ArtMethod>* old_methods = kIsDebugBuild ? klass->GetMethodsPtr() : nullptr;
ReallocMethods(); // No return value to check. Native allocation failure aborts.
LengthPrefixedArray<ArtMethod>* methods = kIsDebugBuild ? klass->GetMethodsPtr() : nullptr;
// Done copying methods, they are all roots in the class now, so we can end the no thread
// suspension assert.
self->EndAssertNoThreadSuspension(old_cause);
if (fill_tables) {
vtable.Assign(UpdateVtable(vtable));
if (UNLIKELY(vtable == nullptr)) {
// The helper has already called self->AssertPendingOOMException();
return false;
}
UpdateIfTable(iftable);
UpdateIMT(out_imt);
}
CheckNoStaleMethodsInDexCache();
ClobberOldMethods(old_methods, methods);
} else {
self->EndAssertNoThreadSuspension(old_cause);
}
if (kIsDebugBuild && !is_interface) {
CheckVTable(self, klass, image_pointer_size);
}
return true;
}
// Populate the class vtable and itable. Compute return type indices.
bool ClassLinker::LinkMethods(Thread* self,
Handle<mirror::Class> klass,
Handle<mirror::ObjectArray<mirror::Class>> interfaces,
bool* out_new_conflict,
ArtMethod** out_imt) {
self->AllowThreadSuspension();
// We set up the interface lookup table first because we need it to determine if we need
// to update any vtable entries with new default method implementations.
if (!SetupInterfaceLookupTable(self, klass, interfaces)) {
return false;
}
// Link virtual methods then interface methods.
Runtime* const runtime = Runtime::Current();
LinkMethodsHelper helper(this, klass, self, runtime);
return helper.LinkVirtualMethods(self, klass) &&
helper.LinkInterfaceMethods(self, klass, runtime, out_new_conflict, out_imt);
}
class ClassLinker::LinkFieldsHelper {
public:
static bool LinkFields(ClassLinker* class_linker,
Thread* self,
Handle<mirror::Class> klass,
bool is_static,
size_t* class_size)
REQUIRES_SHARED(Locks::mutator_lock_);
private:
enum class FieldTypeOrder : uint16_t;
class FieldGaps;
struct FieldTypeOrderAndIndex {
FieldTypeOrder field_type_order;
uint16_t field_index;
};
static FieldTypeOrder FieldTypeOrderFromFirstDescriptorCharacter(char first_char);
template <size_t kSize>
static MemberOffset AssignFieldOffset(ArtField* field, MemberOffset field_offset)
REQUIRES_SHARED(Locks::mutator_lock_);
};
// We use the following order of field types for assigning offsets.
// Some fields can be shuffled forward to fill gaps, see `ClassLinker::LinkFields()`.
enum class ClassLinker::LinkFieldsHelper::FieldTypeOrder : uint16_t {
kReference = 0u,
kLong,
kDouble,
kInt,
kFloat,
kChar,
kShort,
kBoolean,
kByte,
kLast64BitType = kDouble,
kLast32BitType = kFloat,
kLast16BitType = kShort,
};
ALWAYS_INLINE
ClassLinker::LinkFieldsHelper::FieldTypeOrder
ClassLinker::LinkFieldsHelper::FieldTypeOrderFromFirstDescriptorCharacter(char first_char) {
switch (first_char) {
case 'J':
return FieldTypeOrder::kLong;
case 'D':
return FieldTypeOrder::kDouble;
case 'I':
return FieldTypeOrder::kInt;
case 'F':
return FieldTypeOrder::kFloat;
case 'C':
return FieldTypeOrder::kChar;
case 'S':
return FieldTypeOrder::kShort;
case 'Z':
return FieldTypeOrder::kBoolean;
case 'B':
return FieldTypeOrder::kByte;
default:
DCHECK(first_char == 'L' || first_char == '[') << first_char;
return FieldTypeOrder::kReference;
}
}
// Gaps where we can insert fields in object layout.
class ClassLinker::LinkFieldsHelper::FieldGaps {
public:
template <uint32_t kSize>
ALWAYS_INLINE MemberOffset AlignFieldOffset(MemberOffset field_offset) {
static_assert(kSize == 2u || kSize == 4u || kSize == 8u);
if (!IsAligned<kSize>(field_offset.Uint32Value())) {
uint32_t gap_start = field_offset.Uint32Value();
field_offset = MemberOffset(RoundUp(gap_start, kSize));
AddGaps<kSize - 1u>(gap_start, field_offset.Uint32Value());
}
return field_offset;
}
template <uint32_t kSize>
bool HasGap() const {
static_assert(kSize == 1u || kSize == 2u || kSize == 4u);
return (kSize == 1u && gap1_offset_ != kNoOffset) ||
(kSize <= 2u && gap2_offset_ != kNoOffset) ||
gap4_offset_ != kNoOffset;
}
template <uint32_t kSize>
MemberOffset ReleaseGap() {
static_assert(kSize == 1u || kSize == 2u || kSize == 4u);
uint32_t result;
if (kSize == 1u && gap1_offset_ != kNoOffset) {
DCHECK(gap2_offset_ == kNoOffset || gap2_offset_ > gap1_offset_);
DCHECK(gap4_offset_ == kNoOffset || gap4_offset_ > gap1_offset_);
result = gap1_offset_;
gap1_offset_ = kNoOffset;
} else if (kSize <= 2u && gap2_offset_ != kNoOffset) {
DCHECK(gap4_offset_ == kNoOffset || gap4_offset_ > gap2_offset_);
result = gap2_offset_;
gap2_offset_ = kNoOffset;
if (kSize < 2u) {
AddGaps<1u>(result + kSize, result + 2u);
}
} else {
DCHECK_NE(gap4_offset_, kNoOffset);
result = gap4_offset_;
gap4_offset_ = kNoOffset;
if (kSize < 4u) {
AddGaps<kSize | 2u>(result + kSize, result + 4u);
}
}
return MemberOffset(result);
}
private:
template <uint32_t kGapsToCheck>
void AddGaps(uint32_t gap_start, uint32_t gap_end) {
if ((kGapsToCheck & 1u) != 0u) {
DCHECK_LT(gap_start, gap_end);
DCHECK_ALIGNED(gap_end, 2u);
if ((gap_start & 1u) != 0u) {
DCHECK_EQ(gap1_offset_, kNoOffset);
gap1_offset_ = gap_start;
gap_start += 1u;
if (kGapsToCheck == 1u || gap_start == gap_end) {
DCHECK_EQ(gap_start, gap_end);
return;
}
}
}
if ((kGapsToCheck & 2u) != 0u) {
DCHECK_LT(gap_start, gap_end);
DCHECK_ALIGNED(gap_start, 2u);
DCHECK_ALIGNED(gap_end, 4u);
if ((gap_start & 2u) != 0u) {
DCHECK_EQ(gap2_offset_, kNoOffset);
gap2_offset_ = gap_start;
gap_start += 2u;
if (kGapsToCheck <= 3u || gap_start == gap_end) {
DCHECK_EQ(gap_start, gap_end);
return;
}
}
}
if ((kGapsToCheck & 4u) != 0u) {
DCHECK_LT(gap_start, gap_end);
DCHECK_ALIGNED(gap_start, 4u);
DCHECK_ALIGNED(gap_end, 8u);
DCHECK_EQ(gap_start + 4u, gap_end);
DCHECK_EQ(gap4_offset_, kNoOffset);
gap4_offset_ = gap_start;
return;
}
DCHECK(false) << "Remaining gap: " << gap_start << " to " << gap_end
<< " after checking " << kGapsToCheck;
}
static constexpr uint32_t kNoOffset = static_cast<uint32_t>(-1);
uint32_t gap4_offset_ = kNoOffset;
uint32_t gap2_offset_ = kNoOffset;
uint32_t gap1_offset_ = kNoOffset;
};
template <size_t kSize>
ALWAYS_INLINE
MemberOffset ClassLinker::LinkFieldsHelper::AssignFieldOffset(ArtField* field,
MemberOffset field_offset) {
DCHECK_ALIGNED(field_offset.Uint32Value(), kSize);
DCHECK_EQ(Primitive::ComponentSize(field->GetTypeAsPrimitiveType()), kSize);
field->SetOffset(field_offset);
return MemberOffset(field_offset.Uint32Value() + kSize);
}
bool ClassLinker::LinkFieldsHelper::LinkFields(ClassLinker* class_linker,
Thread* self,
Handle<mirror::Class> klass,
bool is_static,
size_t* class_size) {
self->AllowThreadSuspension();
const size_t num_fields = is_static ? klass->NumStaticFields() : klass->NumInstanceFields();
LengthPrefixedArray<ArtField>* const fields = is_static ? klass->GetSFieldsPtr() :
klass->GetIFieldsPtr();
// Initialize field_offset
MemberOffset field_offset(0);
if (is_static) {
field_offset = klass->GetFirstReferenceStaticFieldOffsetDuringLinking(
class_linker->GetImagePointerSize());
} else {
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
if (super_class != nullptr) {
CHECK(super_class->IsResolved())
<< klass->PrettyClass() << " " << super_class->PrettyClass();
field_offset = MemberOffset(super_class->GetObjectSize());
}
}
CHECK_EQ(num_fields == 0, fields == nullptr) << klass->PrettyClass();
// we want a relatively stable order so that adding new fields
// minimizes disruption of C++ version such as Class and Method.
//
// The overall sort order order is:
// 1) All object reference fields, sorted alphabetically.
// 2) All java long (64-bit) integer fields, sorted alphabetically.
// 3) All java double (64-bit) floating point fields, sorted alphabetically.
// 4) All java int (32-bit) integer fields, sorted alphabetically.
// 5) All java float (32-bit) floating point fields, sorted alphabetically.
// 6) All java char (16-bit) integer fields, sorted alphabetically.
// 7) All java short (16-bit) integer fields, sorted alphabetically.
// 8) All java boolean (8-bit) integer fields, sorted alphabetically.
// 9) All java byte (8-bit) integer fields, sorted alphabetically.
//
// (References are first to increase the chance of reference visiting
// being able to take a fast path using a bitmap of references at the
// start of the object, see `Class::reference_instance_offsets_`.)
//
// Once the fields are sorted in this order we will attempt to fill any gaps
// that might be present in the memory layout of the structure.
// Note that we shall not fill gaps between the superclass fields.
// Collect fields and their "type order index" (see numbered points above).
const char* old_no_suspend_cause = self->StartAssertNoThreadSuspension(
"Using plain ArtField references");
constexpr size_t kStackBufferEntries = 64; // Avoid allocations for small number of fields.
FieldTypeOrderAndIndex stack_buffer[kStackBufferEntries];
std::vector<FieldTypeOrderAndIndex> heap_buffer;
ArrayRef<FieldTypeOrderAndIndex> sorted_fields;
if (num_fields <= kStackBufferEntries) {
sorted_fields = ArrayRef<FieldTypeOrderAndIndex>(stack_buffer, num_fields);
} else {
heap_buffer.resize(num_fields);
sorted_fields = ArrayRef<FieldTypeOrderAndIndex>(heap_buffer);
}
size_t num_reference_fields = 0;
size_t primitive_fields_start = num_fields;
DCHECK_LE(num_fields, 1u << 16);
for (size_t i = 0; i != num_fields; ++i) {
ArtField* field = &fields->At(i);
const char* descriptor = field->GetTypeDescriptor();
FieldTypeOrder field_type_order = FieldTypeOrderFromFirstDescriptorCharacter(descriptor[0]);
uint16_t field_index = dchecked_integral_cast<uint16_t>(i);
// Insert references to the start, other fields to the end.
DCHECK_LT(num_reference_fields, primitive_fields_start);
if (field_type_order == FieldTypeOrder::kReference) {
sorted_fields[num_reference_fields] = { field_type_order, field_index };
++num_reference_fields;
} else {
--primitive_fields_start;
sorted_fields[primitive_fields_start] = { field_type_order, field_index };
}
}
DCHECK_EQ(num_reference_fields, primitive_fields_start);
// Reference fields are already sorted by field index (and dex field index).
DCHECK(std::is_sorted(
sorted_fields.begin(),
sorted_fields.begin() + num_reference_fields,
[fields](const auto& lhs, const auto& rhs) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtField* lhs_field = &fields->At(lhs.field_index);
ArtField* rhs_field = &fields->At(rhs.field_index);
CHECK_EQ(lhs_field->GetTypeAsPrimitiveType(), Primitive::kPrimNot);
CHECK_EQ(rhs_field->GetTypeAsPrimitiveType(), Primitive::kPrimNot);
CHECK_EQ(lhs_field->GetDexFieldIndex() < rhs_field->GetDexFieldIndex(),
lhs.field_index < rhs.field_index);
return lhs_field->GetDexFieldIndex() < rhs_field->GetDexFieldIndex();
}));
// Primitive fields were stored in reverse order of their field index (and dex field index).
DCHECK(std::is_sorted(
sorted_fields.begin() + primitive_fields_start,
sorted_fields.end(),
[fields](const auto& lhs, const auto& rhs) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtField* lhs_field = &fields->At(lhs.field_index);
ArtField* rhs_field = &fields->At(rhs.field_index);
CHECK_NE(lhs_field->GetTypeAsPrimitiveType(), Primitive::kPrimNot);
CHECK_NE(rhs_field->GetTypeAsPrimitiveType(), Primitive::kPrimNot);
CHECK_EQ(lhs_field->GetDexFieldIndex() > rhs_field->GetDexFieldIndex(),
lhs.field_index > rhs.field_index);
return lhs.field_index > rhs.field_index;
}));
// Sort the primitive fields by the field type order, then field index.
std::sort(sorted_fields.begin() + primitive_fields_start,
sorted_fields.end(),
[](const auto& lhs, const auto& rhs) {
if (lhs.field_type_order != rhs.field_type_order) {
return lhs.field_type_order < rhs.field_type_order;
} else {
return lhs.field_index < rhs.field_index;
}
});
// Primitive fields are now sorted by field size (descending), then type, then field index.
DCHECK(std::is_sorted(
sorted_fields.begin() + primitive_fields_start,
sorted_fields.end(),
[fields](const auto& lhs, const auto& rhs) REQUIRES_SHARED(Locks::mutator_lock_) {
ArtField* lhs_field = &fields->At(lhs.field_index);
ArtField* rhs_field = &fields->At(rhs.field_index);
Primitive::Type lhs_type = lhs_field->GetTypeAsPrimitiveType();
CHECK_NE(lhs_type, Primitive::kPrimNot);
Primitive::Type rhs_type = rhs_field->GetTypeAsPrimitiveType();
CHECK_NE(rhs_type, Primitive::kPrimNot);
if (lhs_type != rhs_type) {
size_t lhs_size = Primitive::ComponentSize(lhs_type);
size_t rhs_size = Primitive::ComponentSize(rhs_type);
return (lhs_size != rhs_size) ? (lhs_size > rhs_size) : (lhs_type < rhs_type);
} else {
return lhs_field->GetDexFieldIndex() < rhs_field->GetDexFieldIndex();
}
}));
// Process reference fields.
FieldGaps field_gaps;
size_t index = 0u;
if (num_reference_fields != 0u) {
constexpr size_t kReferenceSize = sizeof(mirror::HeapReference<mirror::Object>);
field_offset = field_gaps.AlignFieldOffset<kReferenceSize>(field_offset);
for (; index != num_reference_fields; ++index) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
field_offset = AssignFieldOffset<kReferenceSize>(field, field_offset);
}
}
// Process 64-bit fields.
if (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast64BitType) {
field_offset = field_gaps.AlignFieldOffset<8u>(field_offset);
while (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast64BitType) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
field_offset = AssignFieldOffset<8u>(field, field_offset);
++index;
}
}
// Process 32-bit fields.
if (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast32BitType) {
field_offset = field_gaps.AlignFieldOffset<4u>(field_offset);
if (field_gaps.HasGap<4u>()) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
AssignFieldOffset<4u>(field, field_gaps.ReleaseGap<4u>()); // Ignore return value.
++index;
DCHECK(!field_gaps.HasGap<4u>()); // There can be only one gap for a 32-bit field.
}
while (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast32BitType) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
field_offset = AssignFieldOffset<4u>(field, field_offset);
++index;
}
}
// Process 16-bit fields.
if (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast16BitType) {
field_offset = field_gaps.AlignFieldOffset<2u>(field_offset);
while (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast16BitType &&
field_gaps.HasGap<2u>()) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
AssignFieldOffset<2u>(field, field_gaps.ReleaseGap<2u>()); // Ignore return value.
++index;
}
while (index != num_fields &&
sorted_fields[index].field_type_order <= FieldTypeOrder::kLast16BitType) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
field_offset = AssignFieldOffset<2u>(field, field_offset);
++index;
}
}
// Process 8-bit fields.
for (; index != num_fields && field_gaps.HasGap<1u>(); ++index) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
AssignFieldOffset<1u>(field, field_gaps.ReleaseGap<1u>()); // Ignore return value.
}
for (; index != num_fields; ++index) {
ArtField* field = &fields->At(sorted_fields[index].field_index);
field_offset = AssignFieldOffset<1u>(field, field_offset);
}
self->EndAssertNoThreadSuspension(old_no_suspend_cause);
// We lie to the GC about the java.lang.ref.Reference.referent field, so it doesn't scan it.
DCHECK(!class_linker->init_done_ || !klass->DescriptorEquals("Ljava/lang/ref/Reference;"));
if (!is_static &&
UNLIKELY(!class_linker->init_done_) &&
klass->DescriptorEquals("Ljava/lang/ref/Reference;")) {
// We know there are no non-reference fields in the Reference classes, and we know
// that 'referent' is alphabetically last, so this is easy...
CHECK_EQ(num_reference_fields, num_fields) << klass->PrettyClass();
CHECK_STREQ(fields->At(num_fields - 1).GetName(), "referent")
<< klass->PrettyClass();
--num_reference_fields;
}
size_t size = field_offset.Uint32Value();
// Update klass
if (is_static) {
klass->SetNumReferenceStaticFields(num_reference_fields);
*class_size = size;
} else {
klass->SetNumReferenceInstanceFields(num_reference_fields);
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
if (num_reference_fields == 0 || super_class == nullptr) {
// object has one reference field, klass, but we ignore it since we always visit the class.
// super_class is null iff the class is java.lang.Object.
if (super_class == nullptr ||
(super_class->GetClassFlags() & mirror::kClassFlagNoReferenceFields) != 0) {
klass->SetClassFlags(klass->GetClassFlags() | mirror::kClassFlagNoReferenceFields);
}
}
if (kIsDebugBuild) {
DCHECK_EQ(super_class == nullptr, klass->DescriptorEquals("Ljava/lang/Object;"));
size_t total_reference_instance_fields = 0;
ObjPtr<mirror::Class> cur_super = klass.Get();
while (cur_super != nullptr) {
total_reference_instance_fields += cur_super->NumReferenceInstanceFieldsDuringLinking();
cur_super = cur_super->GetSuperClass();
}
if (super_class == nullptr) {
CHECK_EQ(total_reference_instance_fields, 1u) << klass->PrettyDescriptor();
} else {
// Check that there is at least num_reference_fields other than Object.class.
CHECK_GE(total_reference_instance_fields, 1u + num_reference_fields)
<< klass->PrettyClass();
}
}
if (!klass->IsVariableSize()) {
std::string temp;
DCHECK_GE(size, sizeof(mirror::Object)) << klass->GetDescriptor(&temp);
size_t previous_size = klass->GetObjectSize();
if (previous_size != 0) {
// Make sure that we didn't originally have an incorrect size.
CHECK_EQ(previous_size, size) << klass->GetDescriptor(&temp);
}
klass->SetObjectSize(size);
}
}
if (kIsDebugBuild) {
// Make sure that the fields array is ordered by name but all reference
// offsets are at the beginning as far as alignment allows.
MemberOffset start_ref_offset = is_static
? klass->GetFirstReferenceStaticFieldOffsetDuringLinking(class_linker->image_pointer_size_)
: klass->GetFirstReferenceInstanceFieldOffset();
MemberOffset end_ref_offset(start_ref_offset.Uint32Value() +
num_reference_fields *
sizeof(mirror::HeapReference<mirror::Object>));
MemberOffset current_ref_offset = start_ref_offset;
for (size_t i = 0; i < num_fields; i++) {
ArtField* field = &fields->At(i);
VLOG(class_linker) << "LinkFields: " << (is_static ? "static" : "instance")
<< " class=" << klass->PrettyClass() << " field=" << field->PrettyField()
<< " offset=" << field->GetOffsetDuringLinking();
if (i != 0) {
ArtField* const prev_field = &fields->At(i - 1);
// NOTE: The field names can be the same. This is not possible in the Java language
// but it's valid Java/dex bytecode and for example proguard can generate such bytecode.
DCHECK_LE(strcmp(prev_field->GetName(), field->GetName()), 0);
}
Primitive::Type type = field->GetTypeAsPrimitiveType();
bool is_primitive = type != Primitive::kPrimNot;
if (klass->DescriptorEquals("Ljava/lang/ref/Reference;") &&
strcmp("referent", field->GetName()) == 0) {
is_primitive = true; // We lied above, so we have to expect a lie here.
}
MemberOffset offset = field->GetOffsetDuringLinking();
if (is_primitive) {
if (offset.Uint32Value() < end_ref_offset.Uint32Value()) {
// Shuffled before references.
size_t type_size = Primitive::ComponentSize(type);
CHECK_LT(type_size, sizeof(mirror::HeapReference<mirror::Object>));
CHECK_LT(offset.Uint32Value(), start_ref_offset.Uint32Value());
CHECK_LE(offset.Uint32Value() + type_size, start_ref_offset.Uint32Value());
CHECK(!IsAligned<sizeof(mirror::HeapReference<mirror::Object>)>(offset.Uint32Value()));
}
} else {
CHECK_EQ(current_ref_offset.Uint32Value(), offset.Uint32Value());
current_ref_offset = MemberOffset(current_ref_offset.Uint32Value() +
sizeof(mirror::HeapReference<mirror::Object>));
}
}
CHECK_EQ(current_ref_offset.Uint32Value(), end_ref_offset.Uint32Value());
}
return true;
}
bool ClassLinker::LinkInstanceFields(Thread* self, Handle<mirror::Class> klass) {
CHECK(klass != nullptr);
return LinkFieldsHelper::LinkFields(this, self, klass, false, nullptr);
}
bool ClassLinker::LinkStaticFields(Thread* self, Handle<mirror::Class> klass, size_t* class_size) {
CHECK(klass != nullptr);
return LinkFieldsHelper::LinkFields(this, self, klass, true, class_size);
}
// Set the bitmap of reference instance field offsets.
void ClassLinker::CreateReferenceInstanceOffsets(Handle<mirror::Class> klass) {
uint32_t reference_offsets = 0;
ObjPtr<mirror::Class> super_class = klass->GetSuperClass();
// Leave the reference offsets as 0 for mirror::Object (the class field is handled specially).
if (super_class != nullptr) {
reference_offsets = super_class->GetReferenceInstanceOffsets();
// Compute reference offsets unless our superclass overflowed.
if (reference_offsets != mirror::Class::kClassWalkSuper) {
size_t num_reference_fields = klass->NumReferenceInstanceFieldsDuringLinking();
if (num_reference_fields != 0u) {
// All of the fields that contain object references are guaranteed be grouped in memory
// starting at an appropriately aligned address after super class object data.
uint32_t start_offset = RoundUp(super_class->GetObjectSize(),
sizeof(mirror::HeapReference<mirror::Object>));
uint32_t start_bit = (start_offset - mirror::kObjectHeaderSize) /
sizeof(mirror::HeapReference<mirror::Object>);
if (start_bit + num_reference_fields > 32) {
reference_offsets = mirror::Class::kClassWalkSuper;
} else {
reference_offsets |= (0xffffffffu << start_bit) &
(0xffffffffu >> (32 - (start_bit + num_reference_fields)));
}
}
}
}
klass->SetReferenceInstanceOffsets(reference_offsets);
}
ObjPtr<mirror::String> ClassLinker::DoResolveString(dex::StringIndex string_idx,
ObjPtr<mirror::DexCache> dex_cache) {
StackHandleScope<1> hs(Thread::Current());
Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(dex_cache));
return DoResolveString(string_idx, h_dex_cache);
}
ObjPtr<mirror::String> ClassLinker::DoResolveString(dex::StringIndex string_idx,
Handle<mirror::DexCache> dex_cache) {
const DexFile& dex_file = *dex_cache->GetDexFile();
uint32_t utf16_length;
const char* utf8_data = dex_file.StringDataAndUtf16LengthByIdx(string_idx, &utf16_length);
ObjPtr<mirror::String> string = intern_table_->InternStrong(utf16_length, utf8_data);
if (string != nullptr) {
dex_cache->SetResolvedString(string_idx, string);
}
return string;
}
ObjPtr<mirror::String> ClassLinker::DoLookupString(dex::StringIndex string_idx,
ObjPtr<mirror::DexCache> dex_cache) {
DCHECK(dex_cache != nullptr);
const DexFile& dex_file = *dex_cache->GetDexFile();
uint32_t utf16_length;
const char* utf8_data = dex_file.StringDataAndUtf16LengthByIdx(string_idx, &utf16_length);
ObjPtr<mirror::String> string =
intern_table_->LookupStrong(Thread::Current(), utf16_length, utf8_data);
if (string != nullptr) {
dex_cache->SetResolvedString(string_idx, string);
}
return string;
}
ObjPtr<mirror::Class> ClassLinker::DoLookupResolvedType(dex::TypeIndex type_idx,
ObjPtr<mirror::Class> referrer) {
return DoLookupResolvedType(type_idx, referrer->GetDexCache(), referrer->GetClassLoader());
}
ObjPtr<mirror::Class> ClassLinker::DoLookupResolvedType(dex::TypeIndex type_idx,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader) {
DCHECK(dex_cache->GetClassLoader() == class_loader);
const DexFile& dex_file = *dex_cache->GetDexFile();
const char* descriptor = dex_file.StringByTypeIdx(type_idx);
ObjPtr<mirror::Class> type = LookupResolvedType(descriptor, class_loader);
if (type != nullptr) {
DCHECK(type->IsResolved());
dex_cache->SetResolvedType(type_idx, type);
}
return type;
}
ObjPtr<mirror::Class> ClassLinker::LookupResolvedType(const char* descriptor,
ObjPtr<mirror::ClassLoader> class_loader) {
DCHECK_NE(*descriptor, '\0') << "descriptor is empty string";
ObjPtr<mirror::Class> type = nullptr;
if (descriptor[1] == '\0') {
// only the descriptors of primitive types should be 1 character long, also avoid class lookup
// for primitive classes that aren't backed by dex files.
type = LookupPrimitiveClass(descriptor[0]);
} else {
Thread* const self = Thread::Current();
DCHECK(self != nullptr);
const size_t hash = ComputeModifiedUtf8Hash(descriptor);
// Find the class in the loaded classes table.
type = LookupClass(self, descriptor, hash, class_loader);
}
return (type != nullptr && type->IsResolved()) ? type : nullptr;
}
template <typename RefType>
ObjPtr<mirror::Class> ClassLinker::DoResolveType(dex::TypeIndex type_idx, RefType referrer) {
StackHandleScope<2> hs(Thread::Current());
Handle<mirror::DexCache> dex_cache(hs.NewHandle(referrer->GetDexCache()));
Handle<mirror::ClassLoader> class_loader(hs.NewHandle(referrer->GetClassLoader()));
return DoResolveType(type_idx, dex_cache, class_loader);
}
// Instantiate the above.
template ObjPtr<mirror::Class> ClassLinker::DoResolveType(dex::TypeIndex type_idx,
ArtField* referrer);
template ObjPtr<mirror::Class> ClassLinker::DoResolveType(dex::TypeIndex type_idx,
ArtMethod* referrer);
template ObjPtr<mirror::Class> ClassLinker::DoResolveType(dex::TypeIndex type_idx,
ObjPtr<mirror::Class> referrer);
ObjPtr<mirror::Class> ClassLinker::DoResolveType(dex::TypeIndex type_idx,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader) {
DCHECK(dex_cache->GetClassLoader() == class_loader.Get());
Thread* self = Thread::Current();
const char* descriptor = dex_cache->GetDexFile()->StringByTypeIdx(type_idx);
ObjPtr<mirror::Class> resolved = FindClass(self, descriptor, class_loader);
if (resolved != nullptr) {
// TODO: we used to throw here if resolved's class loader was not the
// boot class loader. This was to permit different classes with the
// same name to be loaded simultaneously by different loaders
dex_cache->SetResolvedType(type_idx, resolved);
} else {
CHECK(self->IsExceptionPending())
<< "Expected pending exception for failed resolution of: " << descriptor;
// Convert a ClassNotFoundException to a NoClassDefFoundError.
StackHandleScope<1> hs(self);
Handle<mirror::Throwable> cause(hs.NewHandle(self->GetException()));
if (cause->InstanceOf(GetClassRoot(ClassRoot::kJavaLangClassNotFoundException, this))) {
DCHECK(resolved == nullptr); // No Handle needed to preserve resolved.
self->ClearException();
ThrowNoClassDefFoundError("Failed resolution of: %s", descriptor);
self->GetException()->SetCause(cause.Get());
}
}
DCHECK((resolved == nullptr) || resolved->IsResolved())
<< resolved->PrettyDescriptor() << " " << resolved->GetStatus();
return resolved;
}
ArtMethod* ClassLinker::FindResolvedMethod(ObjPtr<mirror::Class> klass,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader,
uint32_t method_idx) {
DCHECK(dex_cache->GetClassLoader() == class_loader);
// Search for the method using dex_cache and method_idx. The Class::Find*Method()
// functions can optimize the search if the dex_cache is the same as the DexCache
// of the class, with fall-back to name and signature search otherwise.
ArtMethod* resolved = nullptr;
if (klass->IsInterface()) {
resolved = klass->FindInterfaceMethod(dex_cache, method_idx, image_pointer_size_);
} else {
resolved = klass->FindClassMethod(dex_cache, method_idx, image_pointer_size_);
}
DCHECK(resolved == nullptr || resolved->GetDeclaringClassUnchecked() != nullptr);
if (resolved != nullptr &&
// We pass AccessMethod::kNone instead of kLinking to not warn yet on the
// access, as we'll be looking if the method can be accessed through an
// interface.
hiddenapi::ShouldDenyAccessToMember(resolved,
hiddenapi::AccessContext(class_loader, dex_cache),
hiddenapi::AccessMethod::kNone)) {
// The resolved method that we have found cannot be accessed due to
// hiddenapi (typically it is declared up the hierarchy and is not an SDK
// method). Try to find an interface method from the implemented interfaces which is
// part of the SDK.
ArtMethod* itf_method = klass->FindAccessibleInterfaceMethod(resolved, image_pointer_size_);
if (itf_method == nullptr) {
// No interface method. Call ShouldDenyAccessToMember again but this time
// with AccessMethod::kLinking to ensure that an appropriate warning is
// logged.
hiddenapi::ShouldDenyAccessToMember(resolved,
hiddenapi::AccessContext(class_loader, dex_cache),
hiddenapi::AccessMethod::kLinking);
resolved = nullptr;
} else {
// We found an interface method that is accessible, continue with the resolved method.
}
}
if (resolved != nullptr) {
// In case of jmvti, the dex file gets verified before being registered, so first
// check if it's registered before checking class tables.
const DexFile& dex_file = *dex_cache->GetDexFile();
DCHECK(!IsDexFileRegistered(Thread::Current(), dex_file) ||
FindClassTable(Thread::Current(), dex_cache) == ClassTableForClassLoader(class_loader))
<< "DexFile referrer: " << dex_file.GetLocation()
<< " ClassLoader: " << DescribeLoaders(class_loader, "");
// Be a good citizen and update the dex cache to speed subsequent calls.
dex_cache->SetResolvedMethod(method_idx, resolved);
// Disable the following invariant check as the verifier breaks it. b/73760543
// const DexFile::MethodId& method_id = dex_file.GetMethodId(method_idx);
// DCHECK(LookupResolvedType(method_id.class_idx_, dex_cache, class_loader) != nullptr)
// << "Method: " << resolved->PrettyMethod() << ", "
// << "Class: " << klass->PrettyClass() << " (" << klass->GetStatus() << "), "
// << "DexFile referrer: " << dex_file.GetLocation();
}
return resolved;
}
// Returns true if `method` is either null or hidden.
// Does not print any warnings if it is hidden.
static bool CheckNoSuchMethod(ArtMethod* method,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader)
REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(dex_cache->GetClassLoader().Ptr() == class_loader.Ptr());
return method == nullptr ||
hiddenapi::ShouldDenyAccessToMember(method,
hiddenapi::AccessContext(class_loader, dex_cache),
hiddenapi::AccessMethod::kNone); // no warnings
}
ArtMethod* ClassLinker::FindIncompatibleMethod(ObjPtr<mirror::Class> klass,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader,
uint32_t method_idx) {
DCHECK(dex_cache->GetClassLoader() == class_loader);
if (klass->IsInterface()) {
ArtMethod* method = klass->FindClassMethod(dex_cache, method_idx, image_pointer_size_);
return CheckNoSuchMethod(method, dex_cache, class_loader) ? nullptr : method;
} else {
// If there was an interface method with the same signature, we would have
// found it in the "copied" methods. Only DCHECK that the interface method
// really does not exist.
if (kIsDebugBuild) {
ArtMethod* method =
klass->FindInterfaceMethod(dex_cache, method_idx, image_pointer_size_);
DCHECK(CheckNoSuchMethod(method, dex_cache, class_loader));
}
return nullptr;
}
}
ArtMethod* ClassLinker::ResolveMethodWithoutInvokeType(uint32_t method_idx,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader) {
DCHECK(dex_cache->GetClassLoader() == class_loader.Get());
ArtMethod* resolved = dex_cache->GetResolvedMethod(method_idx);
Thread::PoisonObjectPointersIfDebug();
if (resolved != nullptr) {
DCHECK(!resolved->IsRuntimeMethod());
DCHECK(resolved->GetDeclaringClassUnchecked() != nullptr) << resolved->GetDexMethodIndex();
return resolved;
}
// Fail, get the declaring class.
const dex::MethodId& method_id = dex_cache->GetDexFile()->GetMethodId(method_idx);
ObjPtr<mirror::Class> klass = ResolveType(method_id.class_idx_, dex_cache, class_loader);
if (klass == nullptr) {
Thread::Current()->AssertPendingException();
return nullptr;
}
if (klass->IsInterface()) {
resolved = klass->FindInterfaceMethod(dex_cache.Get(), method_idx, image_pointer_size_);
} else {
resolved = klass->FindClassMethod(dex_cache.Get(), method_idx, image_pointer_size_);
}
if (resolved != nullptr &&
hiddenapi::ShouldDenyAccessToMember(
resolved,
hiddenapi::AccessContext(class_loader.Get(), dex_cache.Get()),
hiddenapi::AccessMethod::kLinking)) {
resolved = nullptr;
}
return resolved;
}
ArtField* ClassLinker::LookupResolvedField(uint32_t field_idx,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader,
bool is_static) {
DCHECK(dex_cache->GetClassLoader().Ptr() == class_loader.Ptr());
const DexFile& dex_file = *dex_cache->GetDexFile();
const dex::FieldId& field_id = dex_file.GetFieldId(field_idx);
ObjPtr<mirror::Class> klass = dex_cache->GetResolvedType(field_id.class_idx_);
if (klass == nullptr) {
klass = LookupResolvedType(field_id.class_idx_, dex_cache, class_loader);
}
if (klass == nullptr) {
// The class has not been resolved yet, so the field is also unresolved.
return nullptr;
}
DCHECK(klass->IsResolved());
return FindResolvedField(klass, dex_cache, class_loader, field_idx, is_static);
}
ArtField* ClassLinker::ResolveFieldJLS(uint32_t field_idx,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader) {
DCHECK(dex_cache != nullptr);
DCHECK(dex_cache->GetClassLoader() == class_loader.Get());
ArtField* resolved = dex_cache->GetResolvedField(field_idx);
Thread::PoisonObjectPointersIfDebug();
if (resolved != nullptr) {
return resolved;
}
const DexFile& dex_file = *dex_cache->GetDexFile();
const dex::FieldId& field_id = dex_file.GetFieldId(field_idx);
ObjPtr<mirror::Class> klass = ResolveType(field_id.class_idx_, dex_cache, class_loader);
if (klass == nullptr) {
DCHECK(Thread::Current()->IsExceptionPending());
return nullptr;
}
resolved = FindResolvedFieldJLS(klass, dex_cache.Get(), class_loader.Get(), field_idx);
if (resolved == nullptr) {
const char* name = dex_file.GetFieldName(field_id);
const char* type = dex_file.GetFieldTypeDescriptor(field_id);
ThrowNoSuchFieldError("", klass, type, name);
}
return resolved;
}
ArtField* ClassLinker::FindResolvedField(ObjPtr<mirror::Class> klass,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader,
uint32_t field_idx,
bool is_static) {
DCHECK(dex_cache->GetClassLoader() == class_loader);
ArtField* resolved = is_static ? klass->FindStaticField(dex_cache, field_idx)
: klass->FindInstanceField(dex_cache, field_idx);
if (resolved != nullptr &&
hiddenapi::ShouldDenyAccessToMember(resolved,
hiddenapi::AccessContext(class_loader, dex_cache),
hiddenapi::AccessMethod::kLinking)) {
resolved = nullptr;
}
if (resolved != nullptr) {
dex_cache->SetResolvedField(field_idx, resolved);
}
return resolved;
}
ArtField* ClassLinker::FindResolvedFieldJLS(ObjPtr<mirror::Class> klass,
ObjPtr<mirror::DexCache> dex_cache,
ObjPtr<mirror::ClassLoader> class_loader,
uint32_t field_idx) {
DCHECK(dex_cache->GetClassLoader().Ptr() == class_loader.Ptr());
ArtField* resolved = klass->FindField(dex_cache, field_idx);
if (resolved != nullptr &&
hiddenapi::ShouldDenyAccessToMember(resolved,
hiddenapi::AccessContext(class_loader, dex_cache),
hiddenapi::AccessMethod::kLinking)) {
resolved = nullptr;
}
if (resolved != nullptr) {
dex_cache->SetResolvedField(field_idx, resolved);
}
return resolved;
}
ObjPtr<mirror::MethodType> ClassLinker::ResolveMethodType(
Thread* self,
dex::ProtoIndex proto_idx,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader) {
DCHECK(Runtime::Current()->IsMethodHandlesEnabled());
DCHECK(dex_cache != nullptr);
DCHECK(dex_cache->GetClassLoader() == class_loader.Get());
ObjPtr<mirror::MethodType> resolved = dex_cache->GetResolvedMethodType(proto_idx);
if (resolved != nullptr) {
return resolved;
}
StackHandleScope<4> hs(self);
// First resolve the return type.
const DexFile& dex_file = *dex_cache->GetDexFile();
const dex::ProtoId& proto_id = dex_file.GetProtoId(proto_idx);
Handle<mirror::Class> return_type(hs.NewHandle(
ResolveType(proto_id.return_type_idx_, dex_cache, class_loader)));
if (return_type == nullptr) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
// Then resolve the argument types.
//
// TODO: Is there a better way to figure out the number of method arguments
// other than by looking at the shorty ?
const size_t num_method_args = strlen(dex_file.StringDataByIdx(proto_id.shorty_idx_)) - 1;
ObjPtr<mirror::Class> array_of_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>(this);
Handle<mirror::ObjectArray<mirror::Class>> method_params(hs.NewHandle(
mirror::ObjectArray<mirror::Class>::Alloc(self, array_of_class, num_method_args)));
if (method_params == nullptr) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
DexFileParameterIterator it(dex_file, proto_id);
int32_t i = 0;
MutableHandle<mirror::Class> param_class = hs.NewHandle<mirror::Class>(nullptr);
for (; it.HasNext(); it.Next()) {
const dex::TypeIndex type_idx = it.GetTypeIdx();
param_class.Assign(ResolveType(type_idx, dex_cache, class_loader));
if (param_class == nullptr) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
method_params->Set(i++, param_class.Get());
}
DCHECK(!it.HasNext());
Handle<mirror::MethodType> type = hs.NewHandle(
mirror::MethodType::Create(self, return_type, method_params));
if (type != nullptr) {
dex_cache->SetResolvedMethodType(proto_idx, type.Get());
}
return type.Get();
}
ObjPtr<mirror::MethodType> ClassLinker::ResolveMethodType(Thread* self,
dex::ProtoIndex proto_idx,
ArtMethod* referrer) {
StackHandleScope<2> hs(self);
Handle<mirror::DexCache> dex_cache(hs.NewHandle(referrer->GetDexCache()));
Handle<mirror::ClassLoader> class_loader(hs.NewHandle(referrer->GetClassLoader()));
return ResolveMethodType(self, proto_idx, dex_cache, class_loader);
}
ObjPtr<mirror::MethodHandle> ClassLinker::ResolveMethodHandleForField(
Thread* self,
const dex::MethodHandleItem& method_handle,
ArtMethod* referrer) {
DexFile::MethodHandleType handle_type =
static_cast<DexFile::MethodHandleType>(method_handle.method_handle_type_);
mirror::MethodHandle::Kind kind;
bool is_put;
bool is_static;
int32_t num_params;
switch (handle_type) {
case DexFile::MethodHandleType::kStaticPut: {
kind = mirror::MethodHandle::Kind::kStaticPut;
is_put = true;
is_static = true;
num_params = 1;
break;
}
case DexFile::MethodHandleType::kStaticGet: {
kind = mirror::MethodHandle::Kind::kStaticGet;
is_put = false;
is_static = true;
num_params = 0;
break;
}
case DexFile::MethodHandleType::kInstancePut: {
kind = mirror::MethodHandle::Kind::kInstancePut;
is_put = true;
is_static = false;
num_params = 2;
break;
}
case DexFile::MethodHandleType::kInstanceGet: {
kind = mirror::MethodHandle::Kind::kInstanceGet;
is_put = false;
is_static = false;
num_params = 1;
break;
}
case DexFile::MethodHandleType::kInvokeStatic:
case DexFile::MethodHandleType::kInvokeInstance:
case DexFile::MethodHandleType::kInvokeConstructor:
case DexFile::MethodHandleType::kInvokeDirect:
case DexFile::MethodHandleType::kInvokeInterface:
UNREACHABLE();
}
ArtField* target_field =
ResolveField(method_handle.field_or_method_idx_, referrer, is_static);
if (LIKELY(target_field != nullptr)) {
ObjPtr<mirror::Class> target_class = target_field->GetDeclaringClass();
ObjPtr<mirror::Class> referring_class = referrer->GetDeclaringClass();
if (UNLIKELY(!referring_class->CanAccessMember(target_class, target_field->GetAccessFlags()))) {
ThrowIllegalAccessErrorField(referring_class, target_field);
return nullptr;
}
if (UNLIKELY(is_put && target_field->IsFinal())) {
ThrowIllegalAccessErrorField(referring_class, target_field);
return nullptr;
}
} else {
DCHECK(Thread::Current()->IsExceptionPending());
return nullptr;
}
StackHandleScope<4> hs(self);
ObjPtr<mirror::Class> array_of_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>(this);
Handle<mirror::ObjectArray<mirror::Class>> method_params(hs.NewHandle(
mirror::ObjectArray<mirror::Class>::Alloc(self, array_of_class, num_params)));
if (UNLIKELY(method_params == nullptr)) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
Handle<mirror::Class> constructor_class;
Handle<mirror::Class> return_type;
switch (handle_type) {
case DexFile::MethodHandleType::kStaticPut: {
method_params->Set(0, target_field->ResolveType());
return_type = hs.NewHandle(GetClassRoot(ClassRoot::kPrimitiveVoid, this));
break;
}
case DexFile::MethodHandleType::kStaticGet: {
return_type = hs.NewHandle(target_field->ResolveType());
break;
}
case DexFile::MethodHandleType::kInstancePut: {
method_params->Set(0, target_field->GetDeclaringClass());
method_params->Set(1, target_field->ResolveType());
return_type = hs.NewHandle(GetClassRoot(ClassRoot::kPrimitiveVoid, this));
break;
}
case DexFile::MethodHandleType::kInstanceGet: {
method_params->Set(0, target_field->GetDeclaringClass());
return_type = hs.NewHandle(target_field->ResolveType());
break;
}
case DexFile::MethodHandleType::kInvokeStatic:
case DexFile::MethodHandleType::kInvokeInstance:
case DexFile::MethodHandleType::kInvokeConstructor:
case DexFile::MethodHandleType::kInvokeDirect:
case DexFile::MethodHandleType::kInvokeInterface:
UNREACHABLE();
}
for (int32_t i = 0; i < num_params; ++i) {
if (UNLIKELY(method_params->Get(i) == nullptr)) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
}
if (UNLIKELY(return_type.IsNull())) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
Handle<mirror::MethodType>
method_type(hs.NewHandle(mirror::MethodType::Create(self, return_type, method_params)));
if (UNLIKELY(method_type.IsNull())) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
uintptr_t target = reinterpret_cast<uintptr_t>(target_field);
return mirror::MethodHandleImpl::Create(self, target, kind, method_type);
}
ObjPtr<mirror::MethodHandle> ClassLinker::ResolveMethodHandleForMethod(
Thread* self,
const dex::MethodHandleItem& method_handle,
ArtMethod* referrer) {
DexFile::MethodHandleType handle_type =
static_cast<DexFile::MethodHandleType>(method_handle.method_handle_type_);
mirror::MethodHandle::Kind kind;
uint32_t receiver_count = 0;
ArtMethod* target_method = nullptr;
switch (handle_type) {
case DexFile::MethodHandleType::kStaticPut:
case DexFile::MethodHandleType::kStaticGet:
case DexFile::MethodHandleType::kInstancePut:
case DexFile::MethodHandleType::kInstanceGet:
UNREACHABLE();
case DexFile::MethodHandleType::kInvokeStatic: {
kind = mirror::MethodHandle::Kind::kInvokeStatic;
receiver_count = 0;
target_method = ResolveMethod<ResolveMode::kNoChecks>(self,
method_handle.field_or_method_idx_,
referrer,
InvokeType::kStatic);
break;
}
case DexFile::MethodHandleType::kInvokeInstance: {
kind = mirror::MethodHandle::Kind::kInvokeVirtual;
receiver_count = 1;
target_method = ResolveMethod<ResolveMode::kNoChecks>(self,
method_handle.field_or_method_idx_,
referrer,
InvokeType::kVirtual);
break;
}
case DexFile::MethodHandleType::kInvokeConstructor: {
// Constructors are currently implemented as a transform. They
// are special cased later in this method.
kind = mirror::MethodHandle::Kind::kInvokeTransform;
receiver_count = 0;
target_method = ResolveMethod<ResolveMode::kNoChecks>(self,
method_handle.field_or_method_idx_,
referrer,
InvokeType::kDirect);
break;
}
case DexFile::MethodHandleType::kInvokeDirect: {
kind = mirror::MethodHandle::Kind::kInvokeDirect;
receiver_count = 1;
StackHandleScope<2> hs(self);
// A constant method handle with type kInvokeDirect can refer to
// a method that is private or to a method in a super class. To
// disambiguate the two options, we resolve the method ignoring
// the invocation type to determine if the method is private. We
// then resolve again specifying the intended invocation type to
// force the appropriate checks.
target_method = ResolveMethodWithoutInvokeType(method_handle.field_or_method_idx_,
hs.NewHandle(referrer->GetDexCache()),
hs.NewHandle(referrer->GetClassLoader()));
if (UNLIKELY(target_method == nullptr)) {
break;
}
if (target_method->IsPrivate()) {
kind = mirror::MethodHandle::Kind::kInvokeDirect;
target_method = ResolveMethod<ResolveMode::kNoChecks>(self,
method_handle.field_or_method_idx_,
referrer,
InvokeType::kDirect);
} else {
kind = mirror::MethodHandle::Kind::kInvokeSuper;
target_method = ResolveMethod<ResolveMode::kNoChecks>(self,
method_handle.field_or_method_idx_,
referrer,
InvokeType::kSuper);
if (UNLIKELY(target_method == nullptr)) {
break;
}
// Find the method specified in the parent in referring class
// so invoke-super invokes the method in the parent of the
// referrer.
target_method =
referrer->GetDeclaringClass()->FindVirtualMethodForVirtual(target_method,
kRuntimePointerSize);
}
break;
}
case DexFile::MethodHandleType::kInvokeInterface: {
kind = mirror::MethodHandle::Kind::kInvokeInterface;
receiver_count = 1;
target_method = ResolveMethod<ResolveMode::kNoChecks>(self,
method_handle.field_or_method_idx_,
referrer,
InvokeType::kInterface);
break;
}
}
if (UNLIKELY(target_method == nullptr)) {
DCHECK(Thread::Current()->IsExceptionPending());
return nullptr;
}
ObjPtr<mirror::Class> target_class = target_method->GetDeclaringClass();
ObjPtr<mirror::Class> referring_class = referrer->GetDeclaringClass();
uint32_t access_flags = target_method->GetAccessFlags();
if (UNLIKELY(!referring_class->CanAccessMember(target_class, access_flags))) {
ThrowIllegalAccessErrorMethod(referring_class, target_method);
return nullptr;
}
// Calculate the number of parameters from the method shorty. We add the
// receiver count (0 or 1) and deduct one for the return value.
uint32_t shorty_length;
target_method->GetShorty(&shorty_length);
int32_t num_params = static_cast<int32_t>(shorty_length + receiver_count - 1);
StackHandleScope<5> hs(self);
ObjPtr<mirror::Class> array_of_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>(this);
Handle<mirror::ObjectArray<mirror::Class>> method_params(hs.NewHandle(
mirror::ObjectArray<mirror::Class>::Alloc(self, array_of_class, num_params)));
if (method_params.Get() == nullptr) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
const DexFile* dex_file = referrer->GetDexFile();
const dex::MethodId& method_id = dex_file->GetMethodId(method_handle.field_or_method_idx_);
int32_t index = 0;
if (receiver_count != 0) {
// Insert receiver. Use the class identified in the method handle rather than the declaring
// class of the resolved method which may be super class or default interface method
// (b/115964401).
ObjPtr<mirror::Class> receiver_class = LookupResolvedType(method_id.class_idx_, referrer);
// receiver_class should have been resolved when resolving the target method.
DCHECK(receiver_class != nullptr);
method_params->Set(index++, receiver_class);
}
const dex::ProtoId& proto_id = dex_file->GetProtoId(method_id.proto_idx_);
DexFileParameterIterator it(*dex_file, proto_id);
while (it.HasNext()) {
DCHECK_LT(index, num_params);
const dex::TypeIndex type_idx = it.GetTypeIdx();
ObjPtr<mirror::Class> klass = ResolveType(type_idx, referrer);
if (nullptr == klass) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
method_params->Set(index++, klass);
it.Next();
}
Handle<mirror::Class> return_type =
hs.NewHandle(ResolveType(proto_id.return_type_idx_, referrer));
if (UNLIKELY(return_type.IsNull())) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
Handle<mirror::MethodType>
method_type(hs.NewHandle(mirror::MethodType::Create(self, return_type, method_params)));
if (UNLIKELY(method_type.IsNull())) {
DCHECK(self->IsExceptionPending());
return nullptr;
}
if (UNLIKELY(handle_type == DexFile::MethodHandleType::kInvokeConstructor)) {
Handle<mirror::Class> constructor_class = hs.NewHandle(target_method->GetDeclaringClass());
Handle<mirror::MethodHandlesLookup> lookup =
hs.NewHandle(mirror::MethodHandlesLookup::GetDefault(self));
return lookup->FindConstructor(self, constructor_class, method_type);
}
uintptr_t target = reinterpret_cast<uintptr_t>(target_method);
return mirror::MethodHandleImpl::Create(self, target, kind, method_type);
}
ObjPtr<mirror::MethodHandle> ClassLinker::ResolveMethodHandle(Thread* self,
uint32_t method_handle_idx,
ArtMethod* referrer)
REQUIRES_SHARED(Locks::mutator_lock_) {
const DexFile* const dex_file = referrer->GetDexFile();
const dex::MethodHandleItem& method_handle = dex_file->GetMethodHandle(method_handle_idx);
switch (static_cast<DexFile::MethodHandleType>(method_handle.method_handle_type_)) {
case DexFile::MethodHandleType::kStaticPut:
case DexFile::MethodHandleType::kStaticGet:
case DexFile::MethodHandleType::kInstancePut:
case DexFile::MethodHandleType::kInstanceGet:
return ResolveMethodHandleForField(self, method_handle, referrer);
case DexFile::MethodHandleType::kInvokeStatic:
case DexFile::MethodHandleType::kInvokeInstance:
case DexFile::MethodHandleType::kInvokeConstructor:
case DexFile::MethodHandleType::kInvokeDirect:
case DexFile::MethodHandleType::kInvokeInterface:
return ResolveMethodHandleForMethod(self, method_handle, referrer);
}
}
bool ClassLinker::IsQuickResolutionStub(const void* entry_point) const {
return (entry_point == GetQuickResolutionStub()) ||
(quick_resolution_trampoline_ == entry_point);
}
bool ClassLinker::IsQuickToInterpreterBridge(const void* entry_point) const {
return (entry_point == GetQuickToInterpreterBridge()) ||
(quick_to_interpreter_bridge_trampoline_ == entry_point);
}
bool ClassLinker::IsQuickGenericJniStub(const void* entry_point) const {
return (entry_point == GetQuickGenericJniStub()) ||
(quick_generic_jni_trampoline_ == entry_point);
}
bool ClassLinker::IsJniDlsymLookupStub(const void* entry_point) const {
return entry_point == GetJniDlsymLookupStub() ||
(jni_dlsym_lookup_trampoline_ == entry_point);
}
bool ClassLinker::IsJniDlsymLookupCriticalStub(const void* entry_point) const {
return entry_point == GetJniDlsymLookupCriticalStub() ||
(jni_dlsym_lookup_critical_trampoline_ == entry_point);
}
const void* ClassLinker::GetRuntimeQuickGenericJniStub() const {
return GetQuickGenericJniStub();
}
void ClassLinker::SetEntryPointsToInterpreter(ArtMethod* method) const {
if (!method->IsNative()) {
method->SetEntryPointFromQuickCompiledCode(GetQuickToInterpreterBridge());
} else {
method->SetEntryPointFromQuickCompiledCode(GetQuickGenericJniStub());
}
}
void ClassLinker::SetEntryPointsForObsoleteMethod(ArtMethod* method) const {
DCHECK(method->IsObsolete());
// We cannot mess with the entrypoints of native methods because they are used to determine how
// large the method's quick stack frame is. Without this information we cannot walk the stacks.
if (!method->IsNative()) {
method->SetEntryPointFromQuickCompiledCode(GetInvokeObsoleteMethodStub());
}
}
void ClassLinker::DumpForSigQuit(std::ostream& os) {
ScopedObjectAccess soa(Thread::Current());
ReaderMutexLock mu(soa.Self(), *Locks::classlinker_classes_lock_);
os << "Zygote loaded classes=" << NumZygoteClasses() << " post zygote classes="
<< NumNonZygoteClasses() << "\n";
ReaderMutexLock mu2(soa.Self(), *Locks::dex_lock_);
os << "Dumping registered class loaders\n";
size_t class_loader_index = 0;
for (const ClassLoaderData& class_loader : class_loaders_) {
ObjPtr<mirror::ClassLoader> loader =
ObjPtr<mirror::ClassLoader>::DownCast(soa.Self()->DecodeJObject(class_loader.weak_root));
if (loader != nullptr) {
os << "#" << class_loader_index++ << " " << loader->GetClass()->PrettyDescriptor() << ": [";
bool saw_one_dex_file = false;
for (const auto& entry : dex_caches_) {
const DexCacheData& dex_cache = entry.second;
if (dex_cache.class_table == class_loader.class_table) {
if (saw_one_dex_file) {
os << ":";
}
saw_one_dex_file = true;
os << entry.first->GetLocation();
}
}
os << "]";
bool found_parent = false;
if (loader->GetParent() != nullptr) {
size_t parent_index = 0;
for (const ClassLoaderData& class_loader2 : class_loaders_) {
ObjPtr<mirror::ClassLoader> loader2 = ObjPtr<mirror::ClassLoader>::DownCast(
soa.Self()->DecodeJObject(class_loader2.weak_root));
if (loader2 == loader->GetParent()) {
os << ", parent #" << parent_index;
found_parent = true;
break;
}
parent_index++;
}
if (!found_parent) {
os << ", unregistered parent of type "
<< loader->GetParent()->GetClass()->PrettyDescriptor();
}
} else {
os << ", no parent";
}
os << "\n";
}
}
os << "Done dumping class loaders\n";
Runtime* runtime = Runtime::Current();
os << "Classes initialized: " << runtime->GetStat(KIND_GLOBAL_CLASS_INIT_COUNT) << " in "
<< PrettyDuration(runtime->GetStat(KIND_GLOBAL_CLASS_INIT_TIME)) << "\n";
}
class CountClassesVisitor : public ClassLoaderVisitor {
public:
CountClassesVisitor() : num_zygote_classes(0), num_non_zygote_classes(0) {}
void Visit(ObjPtr<mirror::ClassLoader> class_loader)
REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_) override {
ClassTable* const class_table = class_loader->GetClassTable();
if (class_table != nullptr) {
num_zygote_classes += class_table->NumZygoteClasses(class_loader);
num_non_zygote_classes += class_table->NumNonZygoteClasses(class_loader);
}
}
size_t num_zygote_classes;
size_t num_non_zygote_classes;
};
size_t ClassLinker::NumZygoteClasses() const {
CountClassesVisitor visitor;
VisitClassLoaders(&visitor);
return visitor.num_zygote_classes + boot_class_table_->NumZygoteClasses(nullptr);
}
size_t ClassLinker::NumNonZygoteClasses() const {
CountClassesVisitor visitor;
VisitClassLoaders(&visitor);
return visitor.num_non_zygote_classes + boot_class_table_->NumNonZygoteClasses(nullptr);
}
size_t ClassLinker::NumLoadedClasses() {
ReaderMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
// Only return non zygote classes since these are the ones which apps which care about.
return NumNonZygoteClasses();
}
pid_t ClassLinker::GetClassesLockOwner() {
return Locks::classlinker_classes_lock_->GetExclusiveOwnerTid();
}
pid_t ClassLinker::GetDexLockOwner() {
return Locks::dex_lock_->GetExclusiveOwnerTid();
}
void ClassLinker::SetClassRoot(ClassRoot class_root, ObjPtr<mirror::Class> klass) {
DCHECK(!init_done_);
DCHECK(klass != nullptr);
DCHECK(klass->GetClassLoader() == nullptr);
mirror::ObjectArray<mirror::Class>* class_roots = class_roots_.Read();
DCHECK(class_roots != nullptr);
DCHECK_LT(static_cast<uint32_t>(class_root), static_cast<uint32_t>(ClassRoot::kMax));
int32_t index = static_cast<int32_t>(class_root);
DCHECK(class_roots->Get(index) == nullptr);
class_roots->Set<false>(index, klass);
}
ObjPtr<mirror::ClassLoader> ClassLinker::CreateWellKnownClassLoader(
Thread* self,
const std::vector<const DexFile*>& dex_files,
Handle<mirror::Class> loader_class,
Handle<mirror::ClassLoader> parent_loader,
Handle<mirror::ObjectArray<mirror::ClassLoader>> shared_libraries,
Handle<mirror::ObjectArray<mirror::ClassLoader>> shared_libraries_after) {
StackHandleScope<5> hs(self);
ArtField* dex_elements_field =
jni::DecodeArtField(WellKnownClasses::dalvik_system_DexPathList_dexElements);
Handle<mirror::Class> dex_elements_class(hs.NewHandle(dex_elements_field->ResolveType()));
DCHECK(dex_elements_class != nullptr);
DCHECK(dex_elements_class->IsArrayClass());
Handle<mirror::ObjectArray<mirror::Object>> h_dex_elements(hs.NewHandle(
mirror::ObjectArray<mirror::Object>::Alloc(self,
dex_elements_class.Get(),
dex_files.size())));
Handle<mirror::Class> h_dex_element_class =
hs.NewHandle(dex_elements_class->GetComponentType());
ArtField* element_file_field =
jni::DecodeArtField(WellKnownClasses::dalvik_system_DexPathList__Element_dexFile);
DCHECK_EQ(h_dex_element_class.Get(), element_file_field->GetDeclaringClass());
ArtField* cookie_field = jni::DecodeArtField(WellKnownClasses::dalvik_system_DexFile_cookie);
DCHECK_EQ(cookie_field->GetDeclaringClass(), element_file_field->LookupResolvedType());
ArtField* file_name_field = jni::DecodeArtField(WellKnownClasses::dalvik_system_DexFile_fileName);
DCHECK_EQ(file_name_field->GetDeclaringClass(), element_file_field->LookupResolvedType());
// Fill the elements array.
int32_t index = 0;
for (const DexFile* dex_file : dex_files) {
StackHandleScope<4> hs2(self);
// CreateWellKnownClassLoader is only used by gtests and compiler.
// Index 0 of h_long_array is supposed to be the oat file but we can leave it null.
Handle<mirror::LongArray> h_long_array = hs2.NewHandle(mirror::LongArray::Alloc(
self,
kDexFileIndexStart + 1));
DCHECK(h_long_array != nullptr);
h_long_array->Set(kDexFileIndexStart, reinterpret_cast64<int64_t>(dex_file));
// Note that this creates a finalizable dalvik.system.DexFile object and a corresponding
// FinalizerReference which will never get cleaned up without a started runtime.
Handle<mirror::Object> h_dex_file = hs2.NewHandle(
cookie_field->GetDeclaringClass()->AllocObject(self));
DCHECK(h_dex_file != nullptr);
cookie_field->SetObject<false>(h_dex_file.Get(), h_long_array.Get());
Handle<mirror::String> h_file_name = hs2.NewHandle(
mirror::String::AllocFromModifiedUtf8(self, dex_file->GetLocation().c_str()));
DCHECK(h_file_name != nullptr);
file_name_field->SetObject<false>(h_dex_file.Get(), h_file_name.Get());
Handle<mirror::Object> h_element = hs2.NewHandle(h_dex_element_class->AllocObject(self));
DCHECK(h_element != nullptr);
element_file_field->SetObject<false>(h_element.Get(), h_dex_file.Get());
h_dex_elements->Set(index, h_element.Get());
index++;
}
DCHECK_EQ(index, h_dex_elements->GetLength());
// Create DexPathList.
Handle<mirror::Object> h_dex_path_list = hs.NewHandle(
dex_elements_field->GetDeclaringClass()->AllocObject(self));
DCHECK(h_dex_path_list != nullptr);
// Set elements.
dex_elements_field->SetObject<false>(h_dex_path_list.Get(), h_dex_elements.Get());
// Create an empty List for the "nativeLibraryDirectories," required for native tests.
// Note: this code is uncommon(oatdump)/testing-only, so don't add further WellKnownClasses
// elements.
{
ArtField* native_lib_dirs = dex_elements_field->GetDeclaringClass()->
FindDeclaredInstanceField("nativeLibraryDirectories", "Ljava/util/List;");
DCHECK(native_lib_dirs != nullptr);
ObjPtr<mirror::Class> list_class = FindSystemClass(self, "Ljava/util/ArrayList;");
DCHECK(list_class != nullptr);
{
StackHandleScope<1> h_list_scope(self);
Handle<mirror::Class> h_list_class(h_list_scope.NewHandle<mirror::Class>(list_class));
bool list_init = EnsureInitialized(self, h_list_class, true, true);
DCHECK(list_init);
list_class = h_list_class.Get();
}
ObjPtr<mirror::Object> list_object = list_class->AllocObject(self);
// Note: we leave the object uninitialized. This must never leak into any non-testing code, but
// is fine for testing. While it violates a Java-code invariant (the elementData field is
// normally never null), as long as one does not try to add elements, this will still
// work.
native_lib_dirs->SetObject<false>(h_dex_path_list.Get(), list_object);
}
// Create the class loader..
Handle<mirror::ClassLoader> h_class_loader = hs.NewHandle<mirror::ClassLoader>(
ObjPtr<mirror::ClassLoader>::DownCast(loader_class->AllocObject(self)));
DCHECK(h_class_loader != nullptr);
// Set DexPathList.
ArtField* path_list_field =
jni::DecodeArtField(WellKnownClasses::dalvik_system_BaseDexClassLoader_pathList);
DCHECK(path_list_field != nullptr);
path_list_field->SetObject<false>(h_class_loader.Get(), h_dex_path_list.Get());
// Make a pretend boot-classpath.
// TODO: Should we scan the image?
ArtField* const parent_field =
jni::DecodeArtField(WellKnownClasses::java_lang_ClassLoader_parent);
DCHECK(parent_field != nullptr);
if (parent_loader.Get() == nullptr) {
ScopedObjectAccessUnchecked soa(self);
ObjPtr<mirror::Object> boot_loader(soa.Decode<mirror::Class>(
WellKnownClasses::java_lang_BootClassLoader)->AllocObject(self));
parent_field->SetObject<false>(h_class_loader.Get(), boot_loader);
} else {
parent_field->SetObject<false>(h_class_loader.Get(), parent_loader.Get());
}
ArtField* shared_libraries_field =
jni::DecodeArtField(WellKnownClasses::dalvik_system_BaseDexClassLoader_sharedLibraryLoaders);
DCHECK(shared_libraries_field != nullptr);
shared_libraries_field->SetObject<false>(h_class_loader.Get(), shared_libraries.Get());
ArtField* shared_libraries_after_field =
jni::DecodeArtField(
WellKnownClasses::dalvik_system_BaseDexClassLoader_sharedLibraryLoadersAfter);
DCHECK(shared_libraries_after_field != nullptr);
shared_libraries_after_field->SetObject<false>(h_class_loader.Get(),
shared_libraries_after.Get());
return h_class_loader.Get();
}
jobject ClassLinker::CreateWellKnownClassLoader(Thread* self,
const std::vector<const DexFile*>& dex_files,
jclass loader_class,
jobject parent_loader,
jobject shared_libraries,
jobject shared_libraries_after) {
CHECK(self->GetJniEnv()->IsSameObject(loader_class,
WellKnownClasses::dalvik_system_PathClassLoader) ||
self->GetJniEnv()->IsSameObject(loader_class,
WellKnownClasses::dalvik_system_DelegateLastClassLoader) ||
self->GetJniEnv()->IsSameObject(loader_class,
WellKnownClasses::dalvik_system_InMemoryDexClassLoader));
// SOAAlreadyRunnable is protected, and we need something to add a global reference.
// We could move the jobject to the callers, but all call-sites do this...
ScopedObjectAccessUnchecked soa(self);
// For now, create a libcore-level DexFile for each ART DexFile. This "explodes" multidex.
StackHandleScope<5> hs(self);
Handle<mirror::Class> h_loader_class =
hs.NewHandle<mirror::Class>(soa.Decode<mirror::Class>(loader_class));
Handle<mirror::ClassLoader> h_parent =
hs.NewHandle<mirror::ClassLoader>(soa.Decode<mirror::ClassLoader>(parent_loader));
Handle<mirror::ObjectArray<mirror::ClassLoader>> h_shared_libraries =
hs.NewHandle(soa.Decode<mirror::ObjectArray<mirror::ClassLoader>>(shared_libraries));
Handle<mirror::ObjectArray<mirror::ClassLoader>> h_shared_libraries_after =
hs.NewHandle(soa.Decode<mirror::ObjectArray<mirror::ClassLoader>>(shared_libraries_after));
ObjPtr<mirror::ClassLoader> loader = CreateWellKnownClassLoader(
self,
dex_files,
h_loader_class,
h_parent,
h_shared_libraries,
h_shared_libraries_after);
// Make it a global ref and return.
ScopedLocalRef<jobject> local_ref(
soa.Env(), soa.Env()->AddLocalReference<jobject>(loader));
return soa.Env()->NewGlobalRef(local_ref.get());
}
jobject ClassLinker::CreatePathClassLoader(Thread* self,
const std::vector<const DexFile*>& dex_files) {
return CreateWellKnownClassLoader(self,
dex_files,
WellKnownClasses::dalvik_system_PathClassLoader,
nullptr);
}
void ClassLinker::DropFindArrayClassCache() {
std::fill_n(find_array_class_cache_, kFindArrayCacheSize, GcRoot<mirror::Class>(nullptr));
find_array_class_cache_next_victim_ = 0;
}
void ClassLinker::VisitClassLoaders(ClassLoaderVisitor* visitor) const {
Thread* const self = Thread::Current();
for (const ClassLoaderData& data : class_loaders_) {
// Need to use DecodeJObject so that we get null for cleared JNI weak globals.
ObjPtr<mirror::ClassLoader> class_loader = ObjPtr<mirror::ClassLoader>::DownCast(
self->DecodeJObject(data.weak_root));
if (class_loader != nullptr) {
visitor->Visit(class_loader);
}
}
}
void ClassLinker::VisitAllocators(AllocatorVisitor* visitor) const {
for (const ClassLoaderData& data : class_loaders_) {
LinearAlloc* alloc = data.allocator;
if (alloc != nullptr && !visitor->Visit(alloc)) {
break;
}
}
}
void ClassLinker::InsertDexFileInToClassLoader(ObjPtr<mirror::Object> dex_file,
ObjPtr<mirror::ClassLoader> class_loader) {
DCHECK(dex_file != nullptr);
Thread* const self = Thread::Current();
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
ClassTable* const table = ClassTableForClassLoader(class_loader);
DCHECK(table != nullptr);
if (table->InsertStrongRoot(dex_file) && class_loader != nullptr) {
// It was not already inserted, perform the write barrier to let the GC know the class loader's
// class table was modified.
WriteBarrier::ForEveryFieldWrite(class_loader);
}
}
void ClassLinker::CleanupClassLoaders() {
Thread* const self = Thread::Current();
std::vector<ClassLoaderData> to_delete;
// Do the delete outside the lock to avoid lock violation in jit code cache.
{
WriterMutexLock mu(self, *Locks::classlinker_classes_lock_);
for (auto it = class_loaders_.begin(); it != class_loaders_.end(); ) {
const ClassLoaderData& data = *it;
// Need to use DecodeJObject so that we get null for cleared JNI weak globals.
ObjPtr<mirror::ClassLoader> class_loader =
ObjPtr<mirror::ClassLoader>::DownCast(self->DecodeJObject(data.weak_root));
if (class_loader != nullptr) {
++it;
} else {
VLOG(class_linker) << "Freeing class loader";
to_delete.push_back(data);
it = class_loaders_.erase(it);
}
}
}
for (ClassLoaderData& data : to_delete) {
// CHA unloading analysis and SingleImplementaion cleanups are required.
DeleteClassLoader(self, data, /*cleanup_cha=*/ true);
}
}
class ClassLinker::FindVirtualMethodHolderVisitor : public ClassVisitor {
public:
FindVirtualMethodHolderVisitor(const ArtMethod* method, PointerSize pointer_size)
: method_(method),
pointer_size_(pointer_size) {}
bool operator()(ObjPtr<mirror::Class> klass) REQUIRES_SHARED(Locks::mutator_lock_) override {
if (klass->GetVirtualMethodsSliceUnchecked(pointer_size_).Contains(method_)) {
holder_ = klass;
}
// Return false to stop searching if holder_ is not null.
return holder_ == nullptr;
}
ObjPtr<mirror::Class> holder_ = nullptr;
const ArtMethod* const method_;
const PointerSize pointer_size_;
};
ObjPtr<mirror::Class> ClassLinker::GetHoldingClassOfCopiedMethod(ArtMethod* method) {
ScopedTrace trace(__FUNCTION__); // Since this function is slow, have a trace to notify people.
CHECK(method->IsCopied());
FindVirtualMethodHolderVisitor visitor(method, image_pointer_size_);
VisitClasses(&visitor);
return visitor.holder_;
}
ObjPtr<mirror::IfTable> ClassLinker::AllocIfTable(Thread* self, size_t ifcount) {
return ObjPtr<mirror::IfTable>::DownCast(ObjPtr<mirror::ObjectArray<mirror::Object>>(
mirror::IfTable::Alloc(self,
GetClassRoot<mirror::ObjectArray<mirror::Object>>(this),
ifcount * mirror::IfTable::kMax)));
}
bool ClassLinker::DenyAccessBasedOnPublicSdk(ArtMethod* art_method ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// Should not be called on ClassLinker, only on AotClassLinker that overrides this.
LOG(FATAL) << "UNREACHABLE";
UNREACHABLE();
}
bool ClassLinker::DenyAccessBasedOnPublicSdk(ArtField* art_field ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// Should not be called on ClassLinker, only on AotClassLinker that overrides this.
LOG(FATAL) << "UNREACHABLE";
UNREACHABLE();
}
bool ClassLinker::DenyAccessBasedOnPublicSdk(const char* type_descriptor ATTRIBUTE_UNUSED) const {
// Should not be called on ClassLinker, only on AotClassLinker that overrides this.
LOG(FATAL) << "UNREACHABLE";
UNREACHABLE();
}
void ClassLinker::SetEnablePublicSdkChecks(bool enabled ATTRIBUTE_UNUSED) {
// Should not be called on ClassLinker, only on AotClassLinker that overrides this.
LOG(FATAL) << "UNREACHABLE";
UNREACHABLE();
}
// Instantiate ClassLinker::AllocClass.
template ObjPtr<mirror::Class> ClassLinker::AllocClass</* kMovable= */ true>(
Thread* self,
ObjPtr<mirror::Class> java_lang_Class,
uint32_t class_size);
template ObjPtr<mirror::Class> ClassLinker::AllocClass</* kMovable= */ false>(
Thread* self,
ObjPtr<mirror::Class> java_lang_Class,
uint32_t class_size);
} // namespace art