ObjPtr<>-ify ClassLinker::FindClass(), fix 1 stale reference use.

Thread::CreateAnnotatedStackTrace() was using a stale
reference `aste_array_class`.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 31113334
Change-Id: I191907c0053456bb57de425aa6ccd9668df818a2
diff --git a/runtime/class_linker-inl.h b/runtime/class_linker-inl.h
index 7a99d3d..25eb85d 100644
--- a/runtime/class_linker-inl.h
+++ b/runtime/class_linker-inl.h
@@ -33,8 +33,8 @@
 
 namespace art {
 
-inline mirror::Class* ClassLinker::FindArrayClass(Thread* self,
-                                                  ObjPtr<mirror::Class>* element_class) {
+inline ObjPtr<mirror::Class> ClassLinker::FindArrayClass(Thread* self,
+                                                         ObjPtr<mirror::Class>* element_class) {
   for (size_t i = 0; i < kFindArrayCacheSize; ++i) {
     // Read the cached array class once to avoid races with other threads setting it.
     ObjPtr<mirror::Class> array_class = find_array_class_cache_[i].Read();
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 0952723..cd03401 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -2059,8 +2059,7 @@
         // 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> class_type = mirror::Class::GetJavaLangClass();
-      ObjPtr<mirror::Class> array_of_class = FindArrayClass(self, &class_type);
+      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.
@@ -2163,9 +2162,9 @@
   return dex_cache.Ptr();
 }
 
-mirror::Class* ClassLinker::AllocClass(Thread* self,
-                                       ObjPtr<mirror::Class> java_lang_Class,
-                                       uint32_t class_size) {
+ObjPtr<mirror::Class> ClassLinker::AllocClass(Thread* self,
+                                              ObjPtr<mirror::Class> java_lang_Class,
+                                              uint32_t class_size) {
   DCHECK_GE(class_size, sizeof(mirror::Class));
   gc::Heap* heap = Runtime::Current()->GetHeap();
   mirror::Class::InitializeClassVisitor visitor(class_size);
@@ -2179,7 +2178,7 @@
   return k->AsClass();
 }
 
-mirror::Class* ClassLinker::AllocClass(Thread* self, uint32_t class_size) {
+ObjPtr<mirror::Class> ClassLinker::AllocClass(Thread* self, uint32_t class_size) {
   return AllocClass(self, GetClassRoot<mirror::Class>(this), class_size);
 }
 
@@ -2190,9 +2189,9 @@
       self, GetClassRoot<mirror::ObjectArray<mirror::StackTraceElement>>(this), length);
 }
 
-mirror::Class* ClassLinker::EnsureResolved(Thread* self,
-                                           const char* descriptor,
-                                           ObjPtr<mirror::Class> klass) {
+ObjPtr<mirror::Class> ClassLinker::EnsureResolved(Thread* self,
+                                                  const char* descriptor,
+                                                  ObjPtr<mirror::Class> klass) {
   DCHECK(klass != nullptr);
   if (kIsDebugBuild) {
     StackHandleScope<1> hs(self);
@@ -2400,9 +2399,9 @@
   return ret;
 }
 
-mirror::Class* ClassLinker::FindClass(Thread* self,
-                                      const char* descriptor,
-                                      Handle<mirror::ClassLoader> class_loader) {
+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();
@@ -2571,12 +2570,12 @@
   return result_ptr.Ptr();
 }
 
-mirror::Class* ClassLinker::DefineClass(Thread* self,
-                                        const char* descriptor,
-                                        size_t hash,
-                                        Handle<mirror::ClassLoader> class_loader,
-                                        const DexFile& dex_file,
-                                        const DexFile::ClassDef& dex_class_def) {
+ObjPtr<mirror::Class> ClassLinker::DefineClass(Thread* self,
+                                               const char* descriptor,
+                                               size_t hash,
+                                               Handle<mirror::ClassLoader> class_loader,
+                                               const DexFile& dex_file,
+                                               const DexFile::ClassDef& dex_class_def) {
   StackHandleScope<3> hs(self);
   auto klass = hs.NewHandle<mirror::Class>(nullptr);
 
@@ -3534,7 +3533,7 @@
   return DexCacheData();
 }
 
-mirror::Class* ClassLinker::CreatePrimitiveClass(Thread* self, Primitive::Type type) {
+ObjPtr<mirror::Class> ClassLinker::CreatePrimitiveClass(Thread* self, Primitive::Type type) {
   ObjPtr<mirror::Class> primitive_class =
       AllocClass(self, mirror::Class::PrimitiveClassSize(image_pointer_size_));
   if (UNLIKELY(primitive_class == nullptr)) {
@@ -3570,8 +3569,10 @@
 // array class; that always comes from the base element class.
 //
 // Returns null with an exception raised on failure.
-mirror::Class* ClassLinker::CreateArrayClass(Thread* self, const char* descriptor, size_t hash,
-                                             Handle<mirror::ClassLoader> class_loader) {
+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);
@@ -3718,27 +3719,27 @@
   return existing.Ptr();
 }
 
-mirror::Class* ClassLinker::FindPrimitiveClass(char type) {
+ObjPtr<mirror::Class> ClassLinker::FindPrimitiveClass(char type) {
   ObjPtr<mirror::ObjectArray<mirror::Class>> class_roots = GetClassRoots();
   switch (type) {
     case 'B':
-      return GetClassRoot(ClassRoot::kPrimitiveByte, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveByte, class_roots);
     case 'C':
-      return GetClassRoot(ClassRoot::kPrimitiveChar, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveChar, class_roots);
     case 'D':
-      return GetClassRoot(ClassRoot::kPrimitiveDouble, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveDouble, class_roots);
     case 'F':
-      return GetClassRoot(ClassRoot::kPrimitiveFloat, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveFloat, class_roots);
     case 'I':
-      return GetClassRoot(ClassRoot::kPrimitiveInt, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveInt, class_roots);
     case 'J':
-      return GetClassRoot(ClassRoot::kPrimitiveLong, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveLong, class_roots);
     case 'S':
-      return GetClassRoot(ClassRoot::kPrimitiveShort, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveShort, class_roots);
     case 'Z':
-      return GetClassRoot(ClassRoot::kPrimitiveBoolean, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveBoolean, class_roots);
     case 'V':
-      return GetClassRoot(ClassRoot::kPrimitiveVoid, class_roots).Ptr();
+      return GetClassRoot(ClassRoot::kPrimitiveVoid, class_roots);
     default:
       break;
   }
@@ -3747,7 +3748,9 @@
   return nullptr;
 }
 
-mirror::Class* ClassLinker::InsertClass(const char* descriptor, ObjPtr<mirror::Class> klass, size_t hash) {
+ObjPtr<mirror::Class> ClassLinker::InsertClass(const char* descriptor,
+                                               ObjPtr<mirror::Class> klass,
+                                               size_t hash) {
   if (VLOG_IS_ON(class_linker)) {
     ObjPtr<mirror::DexCache> dex_cache = klass->GetDexCache();
     std::string source;
@@ -3802,16 +3805,16 @@
   Runtime::Current()->GetHeap()->WriteBarrierEveryFieldOf(klass);
 }
 
-mirror::Class* ClassLinker::LookupClass(Thread* self,
-                           const char* descriptor,
-                           ObjPtr<mirror::ClassLoader> class_loader) {
+ObjPtr<mirror::Class> ClassLinker::LookupClass(Thread* self,
+                                               const char* descriptor,
+                                               ObjPtr<mirror::ClassLoader> class_loader) {
   return LookupClass(self, descriptor, ComputeModifiedUtf8Hash(descriptor), class_loader);
 }
 
-mirror::Class* ClassLinker::LookupClass(Thread* self,
-                                        const char* descriptor,
-                                        size_t hash,
-                                        ObjPtr<mirror::ClassLoader> 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) {
@@ -4264,12 +4267,12 @@
   }
 }
 
-mirror::Class* ClassLinker::CreateProxyClass(ScopedObjectAccessAlreadyRunnable& soa,
-                                             jstring name,
-                                             jobjectArray interfaces,
-                                             jobject loader,
-                                             jobjectArray methods,
-                                             jobjectArray throws) {
+ObjPtr<mirror::Class> ClassLinker::CreateProxyClass(ScopedObjectAccessAlreadyRunnable& soa,
+                                                    jstring name,
+                                                    jobjectArray interfaces,
+                                                    jobject loader,
+                                                    jobjectArray methods,
+                                                    jobjectArray throws) {
   Thread* self = soa.Self();
   StackHandleScope<10> hs(self);
   MutableHandle<mirror::Class> temp_klass(hs.NewHandle(
@@ -8112,8 +8115,7 @@
   // 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> class_type = mirror::Class::GetJavaLangClass();
-  ObjPtr<mirror::Class> array_of_class = FindArrayClass(self, &class_type);
+  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) {
@@ -8219,11 +8221,10 @@
   }
 
   StackHandleScope<4> hs(self);
-  ObjPtr<mirror::Class> class_type = mirror::Class::GetJavaLangClass();
-  ObjPtr<mirror::Class> array_of_class = FindArrayClass(self, &class_type);
+  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.Get() == nullptr)) {
+  if (UNLIKELY(method_params == nullptr)) {
     DCHECK(self->IsExceptionPending());
     return nullptr;
   }
@@ -8398,8 +8399,7 @@
   int32_t num_params = static_cast<int32_t>(shorty_length + receiver_count - 1);
 
   StackHandleScope<7> hs(self);
-  ObjPtr<mirror::Class> class_type = mirror::Class::GetJavaLangClass();
-  ObjPtr<mirror::Class> array_of_class = FindArrayClass(self, &class_type);
+  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) {
@@ -8897,19 +8897,19 @@
   const PointerSize pointer_size_;
 };
 
-mirror::Class* ClassLinker::GetHoldingClassOfCopiedMethod(ArtMethod* method) {
+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_.Ptr();
+  return visitor.holder_;
 }
 
-mirror::IfTable* ClassLinker::AllocIfTable(Thread* self, size_t ifcount) {
-  return down_cast<mirror::IfTable*>(
+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));
+                             ifcount * mirror::IfTable::kMax)));
 }
 
 // Instantiate ResolveMethod.
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index 1f94c43..b38f01d 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -146,22 +146,22 @@
 
   // Finds a class by its descriptor, loading it if necessary.
   // If class_loader is null, searches boot_class_path_.
-  mirror::Class* FindClass(Thread* self,
-                           const char* descriptor,
-                           Handle<mirror::ClassLoader> class_loader)
+  ObjPtr<mirror::Class> FindClass(Thread* self,
+                                  const char* descriptor,
+                                  Handle<mirror::ClassLoader> class_loader)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_);
 
   // Finds a class by its descriptor using the "system" class loader, ie by searching the
   // boot_class_path_.
-  mirror::Class* FindSystemClass(Thread* self, const char* descriptor)
+  ObjPtr<mirror::Class> FindSystemClass(Thread* self, const char* descriptor)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_) {
     return FindClass(self, descriptor, ScopedNullHandle<mirror::ClassLoader>());
   }
 
   // Finds the array class given for the element class.
-  mirror::Class* FindArrayClass(Thread* self, ObjPtr<mirror::Class>* element_class)
+  ObjPtr<mirror::Class> FindArrayClass(Thread* self, ObjPtr<mirror::Class>* element_class)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_);
 
@@ -171,20 +171,20 @@
   }
 
   // Define a new a class based on a ClassDef from a DexFile
-  mirror::Class* DefineClass(Thread* self,
-                             const char* descriptor,
-                             size_t hash,
-                             Handle<mirror::ClassLoader> class_loader,
-                             const DexFile& dex_file,
-                             const DexFile::ClassDef& dex_class_def)
+  ObjPtr<mirror::Class> DefineClass(Thread* self,
+                                    const char* descriptor,
+                                    size_t hash,
+                                    Handle<mirror::ClassLoader> class_loader,
+                                    const DexFile& dex_file,
+                                    const DexFile::ClassDef& dex_class_def)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_);
 
   // Finds a class by its descriptor, returning null if it isn't wasn't loaded
   // by the given 'class_loader'.
-  mirror::Class* LookupClass(Thread* self,
-                             const char* descriptor,
-                             ObjPtr<mirror::ClassLoader> class_loader)
+  ObjPtr<mirror::Class> LookupClass(Thread* self,
+                                    const char* descriptor,
+                                    ObjPtr<mirror::ClassLoader> class_loader)
       REQUIRES(!Locks::classlinker_classes_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -193,7 +193,7 @@
       REQUIRES(!Locks::classlinker_classes_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  mirror::Class* FindPrimitiveClass(char type) REQUIRES_SHARED(Locks::mutator_lock_);
+  ObjPtr<mirror::Class> FindPrimitiveClass(char type) REQUIRES_SHARED(Locks::mutator_lock_);
 
   void DumpForSigQuit(std::ostream& os) REQUIRES(!Locks::classlinker_classes_lock_);
 
@@ -456,7 +456,7 @@
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
-  mirror::IfTable* AllocIfTable(Thread* self, size_t ifcount)
+  ObjPtr<mirror::IfTable> AllocIfTable(Thread* self, size_t ifcount)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
@@ -483,12 +483,12 @@
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_);
 
-  mirror::Class* CreateProxyClass(ScopedObjectAccessAlreadyRunnable& soa,
-                                  jstring name,
-                                  jobjectArray interfaces,
-                                  jobject loader,
-                                  jobjectArray methods,
-                                  jobjectArray throws)
+  ObjPtr<mirror::Class> CreateProxyClass(ScopedObjectAccessAlreadyRunnable& soa,
+                                         jstring name,
+                                         jobjectArray interfaces,
+                                         jobject loader,
+                                         jobjectArray methods,
+                                         jobjectArray throws)
       REQUIRES_SHARED(Locks::mutator_lock_);
   std::string GetDescriptorForProxy(ObjPtr<mirror::Class> proxy_class)
       REQUIRES_SHARED(Locks::mutator_lock_);
@@ -531,7 +531,9 @@
   // Attempts to insert a class into a class table.  Returns null if
   // the class was inserted, otherwise returns an existing class with
   // the same descriptor and ClassLoader.
-  mirror::Class* InsertClass(const char* descriptor, ObjPtr<mirror::Class> klass, size_t hash)
+  ObjPtr<mirror::Class> InsertClass(const char* descriptor,
+                                    ObjPtr<mirror::Class> klass,
+                                    size_t hash)
       REQUIRES(!Locks::classlinker_classes_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -659,7 +661,7 @@
       REQUIRES(!Locks::dex_lock_);
 
   // Get the actual holding class for a copied method. Pretty slow, don't call often.
-  mirror::Class* GetHoldingClassOfCopiedMethod(ArtMethod* method)
+  ObjPtr<mirror::Class> GetHoldingClassOfCopiedMethod(ArtMethod* method)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Returns null if not found.
@@ -763,16 +765,16 @@
       REQUIRES(!Locks::dex_lock_, !Roles::uninterruptible_);
 
   // For early bootstrapping by Init
-  mirror::Class* AllocClass(Thread* self,
-                            ObjPtr<mirror::Class> java_lang_Class,
-                            uint32_t class_size)
+  ObjPtr<mirror::Class> AllocClass(Thread* self,
+                                   ObjPtr<mirror::Class> java_lang_Class,
+                                   uint32_t class_size)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
-  // Alloc* convenience functions to avoid needing to pass in mirror::Class*
-  // values that are known to the ClassLinker such as
-  // kObjectArrayClass and kJavaLangString etc.
-  mirror::Class* AllocClass(Thread* self, uint32_t class_size)
+  // Alloc* convenience functions to avoid needing to pass in ObjPtr<mirror::Class>
+  // values that are known to the ClassLinker such as classes corresponding to
+  // ClassRoot::kObjectArrayClass and ClassRoot::kJavaLangString etc.
+  ObjPtr<mirror::Class> AllocClass(Thread* self, uint32_t class_size)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
@@ -790,14 +792,14 @@
       REQUIRES(!Locks::dex_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
-  mirror::Class* CreatePrimitiveClass(Thread* self, Primitive::Type type)
+  ObjPtr<mirror::Class> CreatePrimitiveClass(Thread* self, Primitive::Type type)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
-  mirror::Class* CreateArrayClass(Thread* self,
-                                  const char* descriptor,
-                                  size_t hash,
-                                  Handle<mirror::ClassLoader> class_loader)
+  ObjPtr<mirror::Class> CreateArrayClass(Thread* self,
+                                         const char* descriptor,
+                                         size_t hash,
+                                         Handle<mirror::ClassLoader> class_loader)
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_, !Roles::uninterruptible_);
 
@@ -889,10 +891,10 @@
 
   // Finds a class by its descriptor, returning NULL if it isn't wasn't loaded
   // by the given 'class_loader'. Uses the provided hash for the descriptor.
-  mirror::Class* LookupClass(Thread* self,
-                             const char* descriptor,
-                             size_t hash,
-                             ObjPtr<mirror::ClassLoader> class_loader)
+  ObjPtr<mirror::Class> LookupClass(Thread* self,
+                                    const char* descriptor,
+                                    size_t hash,
+                                    ObjPtr<mirror::ClassLoader> class_loader)
       REQUIRES(!Locks::classlinker_classes_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -1163,7 +1165,9 @@
   // when resolution has occurred. This happens in mirror::Class::SetStatus. As resolution may
   // retire a class, the version of the class in the table is returned and this may differ from
   // the class passed in.
-  mirror::Class* EnsureResolved(Thread* self, const char* descriptor, ObjPtr<mirror::Class> klass)
+  ObjPtr<mirror::Class> EnsureResolved(Thread* self,
+                                       const char* descriptor,
+                                       ObjPtr<mirror::Class> klass)
       WARN_UNUSED
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::dex_lock_);
diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index 48ec6b6..5d420aa 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -198,7 +198,8 @@
     ASSERT_STREQ(array_descriptor.c_str(), array->GetDescriptor(&temp));
     EXPECT_TRUE(array->GetSuperClass() != nullptr);
     Thread* self = Thread::Current();
-    EXPECT_EQ(class_linker_->FindSystemClass(self, "Ljava/lang/Object;"), array->GetSuperClass());
+    EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(self, "Ljava/lang/Object;"),
+                      array->GetSuperClass());
     EXPECT_TRUE(array->HasSuperClass());
     ASSERT_TRUE(array->GetComponentType() != nullptr);
     ASSERT_GT(strlen(array->GetComponentType()->GetDescriptor(&temp)), 0U);
@@ -1079,27 +1080,27 @@
   ScopedObjectAccess soa(Thread::Current());
   StackHandleScope<5> hs(soa.Self());
   Handle<mirror::LongArray> long_array(hs.NewHandle(mirror::LongArray::Alloc(soa.Self(), 0)));
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "[J"), long_array->GetClass());
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "[J"), long_array->GetClass());
   uintptr_t data_offset = reinterpret_cast<uintptr_t>(long_array->GetData());
   EXPECT_TRUE(IsAligned<8>(data_offset));  // Longs require 8 byte alignment
 
   Handle<mirror::DoubleArray> double_array(hs.NewHandle(mirror::DoubleArray::Alloc(soa.Self(), 0)));
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "[D"), double_array->GetClass());
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "[D"), double_array->GetClass());
   data_offset = reinterpret_cast<uintptr_t>(double_array->GetData());
   EXPECT_TRUE(IsAligned<8>(data_offset));  // Doubles require 8 byte alignment
 
   Handle<mirror::IntArray> int_array(hs.NewHandle(mirror::IntArray::Alloc(soa.Self(), 0)));
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "[I"), int_array->GetClass());
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "[I"), int_array->GetClass());
   data_offset = reinterpret_cast<uintptr_t>(int_array->GetData());
   EXPECT_TRUE(IsAligned<4>(data_offset));  // Ints require 4 byte alignment
 
   Handle<mirror::CharArray> char_array(hs.NewHandle(mirror::CharArray::Alloc(soa.Self(), 0)));
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "[C"), char_array->GetClass());
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "[C"), char_array->GetClass());
   data_offset = reinterpret_cast<uintptr_t>(char_array->GetData());
   EXPECT_TRUE(IsAligned<2>(data_offset));  // Chars require 2 byte alignment
 
   Handle<mirror::ShortArray> short_array(hs.NewHandle(mirror::ShortArray::Alloc(soa.Self(), 0)));
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "[S"), short_array->GetClass());
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "[S"), short_array->GetClass());
   data_offset = reinterpret_cast<uintptr_t>(short_array->GetData());
   EXPECT_TRUE(IsAligned<2>(data_offset));  // Shorts require 2 byte alignment
 
diff --git a/runtime/gc/space/space_test.h b/runtime/gc/space/space_test.h
index d5861ed..c94b666 100644
--- a/runtime/gc/space/space_test.h
+++ b/runtime/gc/space/space_test.h
@@ -53,13 +53,11 @@
   }
 
   mirror::Class* GetByteArrayClass(Thread* self) REQUIRES_SHARED(Locks::mutator_lock_) {
-    StackHandleScope<1> hs(self);
-    auto null_loader(hs.NewHandle<mirror::ClassLoader>(nullptr));
     if (byte_array_class_ == nullptr) {
-      mirror::Class* byte_array_class =
-          Runtime::Current()->GetClassLinker()->FindClass(self, "[B", null_loader);
+      ObjPtr<mirror::Class> byte_array_class =
+          Runtime::Current()->GetClassLinker()->FindSystemClass(self, "[B");
       EXPECT_TRUE(byte_array_class != nullptr);
-      byte_array_class_ = self->GetJniEnv()->NewLocalRef(byte_array_class);
+      byte_array_class_ = self->GetJniEnv()->NewLocalRef(byte_array_class.Ptr());
       EXPECT_TRUE(byte_array_class_ != nullptr);
     }
     return self->DecodeJObject(byte_array_class_)->AsClass();
diff --git a/runtime/hidden_api_test.cc b/runtime/hidden_api_test.cc
index ab0c290..a41d284 100644
--- a/runtime/hidden_api_test.cc
+++ b/runtime/hidden_api_test.cc
@@ -325,8 +325,8 @@
   ASSERT_TRUE(h_iface != nullptr);
 
   // Create the proxy class.
-  std::vector<mirror::Class*> interfaces;
-  interfaces.push_back(h_iface.Get());
+  std::vector<Handle<mirror::Class>> interfaces;
+  interfaces.push_back(h_iface);
   Handle<mirror::Class> proxyClass = hs.NewHandle(proxy_test::GenerateProxyClass(
       soa, jclass_loader_, runtime_->GetClassLinker(), "$Proxy1234", interfaces));
   ASSERT_TRUE(proxyClass != nullptr);
diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index fab3509..56658c3 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -1128,9 +1128,9 @@
 
   StackHandleScope<2> hs(self);
   // Create array for parameter types.
-  ObjPtr<mirror::Class> class_type = mirror::Class::GetJavaLangClass();
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
-  ObjPtr<mirror::Class> class_array_type = class_linker->FindArrayClass(self, &class_type);
+  ObjPtr<mirror::Class> class_array_type =
+      GetClassRoot<mirror::ObjectArray<mirror::Class>>(class_linker);
   Handle<mirror::ObjectArray<mirror::Class>> ptypes = hs.NewHandle(
       mirror::ObjectArray<mirror::Class>::Alloc(self,
                                                 class_array_type,
diff --git a/runtime/interpreter/unstarted_runtime_test.cc b/runtime/interpreter/unstarted_runtime_test.cc
index 88cfafb..fee8375 100644
--- a/runtime/interpreter/unstarted_runtime_test.cc
+++ b/runtime/interpreter/unstarted_runtime_test.cc
@@ -196,7 +196,7 @@
   // Prepare for aborts. Aborts assume that the exception class is already resolved, as the
   // loading code doesn't work under transactions.
   void PrepareForAborts() REQUIRES_SHARED(Locks::mutator_lock_) {
-    mirror::Object* result = Runtime::Current()->GetClassLinker()->FindClass(
+    ObjPtr<mirror::Object> result = Runtime::Current()->GetClassLinker()->FindClass(
         Thread::Current(),
         Transaction::kAbortExceptionSignature,
         ScopedNullHandle<mirror::ClassLoader>());
diff --git a/runtime/method_handles_test.cc b/runtime/method_handles_test.cc
index a947342..0db9551 100644
--- a/runtime/method_handles_test.cc
+++ b/runtime/method_handles_test.cc
@@ -17,6 +17,7 @@
 #include "method_handles.h"
 
 #include "class_linker-inl.h"
+#include "class_root.h"
 #include "common_runtime_test.h"
 #include "handle_scope-inl.h"
 #include "jvalue-inl.h"
@@ -49,12 +50,11 @@
         REQUIRES_SHARED(Locks::mutator_lock_) {
     ClassLinker* cl = Runtime::Current()->GetClassLinker();
     StackHandleScope<2> hs(self);
-    ObjPtr<mirror::Class> class_type = mirror::Class::GetJavaLangClass();
-    ObjPtr<mirror::Class> class_array_type = cl->FindArrayClass(self, &class_type);
+    ObjPtr<mirror::Class> class_array_type = GetClassRoot<mirror::ObjectArray<mirror::Class>>(cl);
     auto parameter_types = hs.NewHandle(
         mirror::ObjectArray<mirror::Class>::Alloc(self, class_array_type, 1));
     parameter_types->Set(0, parameter_type.Get());
-    Handle<mirror::Class> void_class = hs.NewHandle(cl->FindPrimitiveClass('V'));
+    Handle<mirror::Class> void_class = hs.NewHandle(GetClassRoot(ClassRoot::kPrimitiveVoid, cl));
     return mirror::MethodType::Create(self, void_class, parameter_types);
   }
 
diff --git a/runtime/mirror/method_type.cc b/runtime/mirror/method_type.cc
index a8be8b7..483fff5 100644
--- a/runtime/mirror/method_type.cc
+++ b/runtime/mirror/method_type.cc
@@ -28,9 +28,7 @@
 
 ObjPtr<ObjectArray<Class>> AllocatePTypesArray(Thread* self, int count)
     REQUIRES_SHARED(Locks::mutator_lock_) {
-  ObjPtr<Class> class_type = Class::GetJavaLangClass();
-  ObjPtr<Class> class_array_type =
-      Runtime::Current()->GetClassLinker()->FindArrayClass(self, &class_type);
+  ObjPtr<Class> class_array_type = GetClassRoot<mirror::ObjectArray<mirror::Class>>();
   return ObjectArray<Class>::Alloc(self, class_array_type, count);
 }
 
diff --git a/runtime/mirror/method_type_test.cc b/runtime/mirror/method_type_test.cc
index 16bfc73..2bdea72 100644
--- a/runtime/mirror/method_type_test.cc
+++ b/runtime/mirror/method_type_test.cc
@@ -22,6 +22,7 @@
 #include "class-inl.h"
 #include "class_linker-inl.h"
 #include "class_loader.h"
+#include "class_root.h"
 #include "common_runtime_test.h"
 #include "handle_scope-inl.h"
 #include "object_array-inl.h"
@@ -53,8 +54,8 @@
           soa.Self(), FullyQualifiedType(return_type).c_str(), boot_class_loader));
   CHECK(return_clazz != nullptr);
 
-  ObjPtr<mirror::Class> class_type = mirror::Class::GetJavaLangClass();
-  ObjPtr<mirror::Class> class_array_type = class_linker->FindArrayClass(self, &class_type);
+  ObjPtr<mirror::Class> class_array_type =
+      GetClassRoot<mirror::ObjectArray<mirror::Class>>(class_linker);
   Handle<mirror::ObjectArray<mirror::Class>> param_classes = hs.NewHandle(
       mirror::ObjectArray<mirror::Class>::Alloc(self, class_array_type, param_types.size()));
 
diff --git a/runtime/mirror/var_handle.cc b/runtime/mirror/var_handle.cc
index 8311d91..71f41b9 100644
--- a/runtime/mirror/var_handle.cc
+++ b/runtime/mirror/var_handle.cc
@@ -27,6 +27,7 @@
 #include "jvalue-inl.h"
 #include "method_handles-inl.h"
 #include "method_type.h"
+#include "obj_ptr-inl.h"
 #include "well_known_classes.h"
 
 namespace art {
@@ -266,31 +267,22 @@
 
 // Returns the return type associated with an AccessModeTemplate based
 // on the template and the variable type specified.
-Class* GetReturnType(AccessModeTemplate access_mode_template, ObjPtr<Class> varType)
+static ObjPtr<Class> GetReturnType(AccessModeTemplate access_mode_template, ObjPtr<Class> varType)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   DCHECK(varType != nullptr);
   switch (access_mode_template) {
     case AccessModeTemplate::kCompareAndSet:
-      return Runtime::Current()->GetClassLinker()->FindPrimitiveClass('Z');
+      return GetClassRoot(ClassRoot::kPrimitiveBoolean);
     case AccessModeTemplate::kCompareAndExchange:
     case AccessModeTemplate::kGet:
     case AccessModeTemplate::kGetAndUpdate:
-      return varType.Ptr();
+      return varType;
     case AccessModeTemplate::kSet:
-      return Runtime::Current()->GetClassLinker()->FindPrimitiveClass('V');
+      return GetClassRoot(ClassRoot::kPrimitiveVoid);
   }
   return nullptr;
 }
 
-ObjectArray<Class>* NewArrayOfClasses(Thread* self, int count)
-    REQUIRES_SHARED(Locks::mutator_lock_) {
-  Runtime* const runtime = Runtime::Current();
-  ClassLinker* const class_linker = runtime->GetClassLinker();
-  ObjPtr<mirror::Class> class_type = mirror::Class::GetJavaLangClass();
-  ObjPtr<mirror::Class> array_of_class = class_linker->FindArrayClass(self, &class_type);
-  return ObjectArray<Class>::Alloc(Thread::Current(), array_of_class, count);
-}
-
 // Method to insert a read barrier for accessors to reference fields.
 inline void ReadBarrierForVarHandleAccess(ObjPtr<Object> obj, MemberOffset field_offset)
     REQUIRES_SHARED(Locks::mutator_lock_) {
@@ -1410,15 +1402,15 @@
 
 }  // namespace
 
-Class* VarHandle::GetVarType() {
+ObjPtr<Class> VarHandle::GetVarType() {
   return GetFieldObject<Class>(VarTypeOffset());
 }
 
-Class* VarHandle::GetCoordinateType0() {
+ObjPtr<Class> VarHandle::GetCoordinateType0() {
   return GetFieldObject<Class>(CoordinateType0Offset());
 }
 
-Class* VarHandle::GetCoordinateType1() {
+ObjPtr<Class> VarHandle::GetCoordinateType1() {
   return GetFieldObject<Class>(CoordinateType1Offset());
 }
 
@@ -1438,7 +1430,7 @@
   // Check return type first. If the return type of the method
   // of the VarHandle is immaterial.
   if (mt_rtype->GetPrimitiveType() != Primitive::Type::kPrimVoid) {
-    ObjPtr<Class> vh_rtype = GetReturnType(access_mode_template, var_type.Ptr());
+    ObjPtr<Class> vh_rtype = GetReturnType(access_mode_template, var_type);
     if (vh_rtype != mt_rtype) {
       if (!IsReturnTypeConvertible(vh_rtype, mt_rtype)) {
         return MatchKind::kNone;
@@ -1513,9 +1505,9 @@
   return true;
 }
 
-MethodType* VarHandle::GetMethodTypeForAccessMode(Thread* self,
-                                                  ObjPtr<VarHandle> var_handle,
-                                                  AccessMode access_mode) {
+ObjPtr<MethodType> VarHandle::GetMethodTypeForAccessMode(Thread* self,
+                                                         ObjPtr<VarHandle> var_handle,
+                                                         AccessMode access_mode) {
   // This is a static method as the var_handle might be moved by the GC during it's execution.
   AccessModeTemplate access_mode_template = GetAccessModeTemplate(access_mode);
 
@@ -1525,7 +1517,9 @@
   const int32_t ptypes_count = GetNumberOfParameters(access_mode_template,
                                                      vh->GetCoordinateType0(),
                                                      vh->GetCoordinateType1());
-  Handle<ObjectArray<Class>> ptypes = hs.NewHandle(NewArrayOfClasses(self, ptypes_count));
+  ObjPtr<Class> array_of_class = GetClassRoot<ObjectArray<Class>>();
+  Handle<ObjectArray<Class>> ptypes =
+      hs.NewHandle(ObjectArray<Class>::Alloc(Thread::Current(), array_of_class, ptypes_count));
   if (ptypes == nullptr) {
     return nullptr;
   }
@@ -1537,12 +1531,12 @@
                       vh->GetCoordinateType0(),
                       vh->GetCoordinateType1());
   for (int32_t i = 0; i < ptypes_count; ++i) {
-    ptypes->Set(i, ptypes_array[i].Ptr());
+    ptypes->Set(i, ptypes_array[i]);
   }
   return MethodType::Create(self, rtype, ptypes);
 }
 
-MethodType* VarHandle::GetMethodTypeForAccessMode(Thread* self, AccessMode access_mode) {
+ObjPtr<MethodType> VarHandle::GetMethodTypeForAccessMode(Thread* self, AccessMode access_mode) {
   return GetMethodTypeForAccessMode(self, this, access_mode);
 }
 
diff --git a/runtime/mirror/var_handle.h b/runtime/mirror/var_handle.h
index 9829456..48c9d74 100644
--- a/runtime/mirror/var_handle.h
+++ b/runtime/mirror/var_handle.h
@@ -26,6 +26,7 @@
 
 template<class T> class Handle;
 class InstructionOperands;
+template<class T> class ObjPtr;
 
 enum class Intrinsics;
 
@@ -120,7 +121,7 @@
   // AccessMode. No check is made for whether the AccessMode is a
   // supported operation so the MethodType can be used when raising a
   // WrongMethodTypeException exception.
-  MethodType* GetMethodTypeForAccessMode(Thread* self, AccessMode accessMode)
+  ObjPtr<MethodType> GetMethodTypeForAccessMode(Thread* self, AccessMode accessMode)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Returns a string representing the descriptor of the MethodType associated with
@@ -135,7 +136,7 @@
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Gets the variable type that is operated on by this VarHandle instance.
-  Class* GetVarType() REQUIRES_SHARED(Locks::mutator_lock_);
+  ObjPtr<Class> GetVarType() REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Gets the return type descriptor for a named accessor method,
   // nullptr if accessor_method is not supported.
@@ -149,13 +150,13 @@
   static bool GetAccessModeByMethodName(const char* method_name, AccessMode* access_mode);
 
  private:
-  Class* GetCoordinateType0() REQUIRES_SHARED(Locks::mutator_lock_);
-  Class* GetCoordinateType1() REQUIRES_SHARED(Locks::mutator_lock_);
+  ObjPtr<Class> GetCoordinateType0() REQUIRES_SHARED(Locks::mutator_lock_);
+  ObjPtr<Class> GetCoordinateType1() REQUIRES_SHARED(Locks::mutator_lock_);
   int32_t GetAccessModesBitMask() REQUIRES_SHARED(Locks::mutator_lock_);
 
-  static MethodType* GetMethodTypeForAccessMode(Thread* self,
-                                                ObjPtr<VarHandle> var_handle,
-                                                AccessMode access_mode)
+  static ObjPtr<MethodType> GetMethodTypeForAccessMode(Thread* self,
+                                                       ObjPtr<VarHandle> var_handle,
+                                                       AccessMode access_mode)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   static MemberOffset VarTypeOffset() {
diff --git a/runtime/mirror/var_handle_test.cc b/runtime/mirror/var_handle_test.cc
index cb2d628..9df96dd 100644
--- a/runtime/mirror/var_handle_test.cc
+++ b/runtime/mirror/var_handle_test.cc
@@ -130,17 +130,17 @@
   }
 
   // Helper to get the VarType of a VarHandle.
-  static Class* GetVarType(VarHandle* vh) REQUIRES_SHARED(Locks::mutator_lock_) {
+  static ObjPtr<Class> GetVarType(VarHandle* vh) REQUIRES_SHARED(Locks::mutator_lock_) {
     return vh->GetVarType();
   }
 
   // Helper to get the CoordinateType0 of a VarHandle.
-  static Class* GetCoordinateType0(VarHandle* vh) REQUIRES_SHARED(Locks::mutator_lock_) {
+  static ObjPtr<Class> GetCoordinateType0(VarHandle* vh) REQUIRES_SHARED(Locks::mutator_lock_) {
     return vh->GetCoordinateType0();
   }
 
   // Helper to get the CoordinateType1 of a VarHandle.
-  static Class* GetCoordinateType1(VarHandle* vh) REQUIRES_SHARED(Locks::mutator_lock_) {
+  static ObjPtr<Class> GetCoordinateType1(VarHandle* vh) REQUIRES_SHARED(Locks::mutator_lock_) {
     return vh->GetCoordinateType1();
   }
 
@@ -150,7 +150,7 @@
   }
 
  private:
-  static void InitializeVarHandle(VarHandle* vh,
+  static void InitializeVarHandle(ObjPtr<VarHandle> vh,
                                   Handle<Class> var_type,
                                   int32_t access_modes_bit_mask)
       REQUIRES_SHARED(Locks::mutator_lock_) {
@@ -158,7 +158,7 @@
     vh->SetField32<false>(VarHandle::AccessModesBitMaskOffset(), access_modes_bit_mask);
   }
 
-  static void InitializeVarHandle(VarHandle* vh,
+  static void InitializeVarHandle(ObjPtr<VarHandle> vh,
                                   Handle<Class> var_type,
                                   Handle<Class> coordinate_type0,
                                   int32_t access_modes_bit_mask)
@@ -167,7 +167,7 @@
     vh->SetFieldObject<false>(VarHandle::CoordinateType0Offset(), coordinate_type0.Get());
   }
 
-  static void InitializeVarHandle(VarHandle* vh,
+  static void InitializeVarHandle(ObjPtr<VarHandle> vh,
                                   Handle<Class> var_type,
                                   Handle<Class> coordinate_type0,
                                   Handle<Class> coordinate_type1,
diff --git a/runtime/native/java_lang_Class.cc b/runtime/native/java_lang_Class.cc
index 261178b..c6bdfa1 100644
--- a/runtime/native/java_lang_Class.cc
+++ b/runtime/native/java_lang_Class.cc
@@ -215,17 +215,9 @@
   return soa.AddLocalReference<jstring>(mirror::Class::ComputeName(hs.NewHandle(c)));
 }
 
-// TODO: Move this to mirror::Class ? Other mirror types that commonly appear
-// as arrays have a GetArrayClass() method.
-static ObjPtr<mirror::Class> GetClassArrayClass(Thread* self)
-    REQUIRES_SHARED(Locks::mutator_lock_) {
-  ObjPtr<mirror::Class> class_class = mirror::Class::GetJavaLangClass();
-  return Runtime::Current()->GetClassLinker()->FindArrayClass(self, &class_class);
-}
-
 static jobjectArray Class_getInterfacesInternal(JNIEnv* env, jobject javaThis) {
   ScopedFastNativeObjectAccess soa(env);
-  StackHandleScope<4> hs(soa.Self());
+  StackHandleScope<1> hs(soa.Self());
   Handle<mirror::Class> klass = hs.NewHandle(DecodeClass(soa, javaThis));
 
   if (klass->IsProxyClass()) {
@@ -237,10 +229,12 @@
     return nullptr;
   }
 
+  ClassLinker* linker = Runtime::Current()->GetClassLinker();
   const uint32_t num_ifaces = iface_list->Size();
-  Handle<mirror::Class> class_array_class = hs.NewHandle(GetClassArrayClass(soa.Self()));
-  Handle<mirror::ObjectArray<mirror::Class>> ifaces = hs.NewHandle(
-      mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class.Get(), num_ifaces));
+  ObjPtr<mirror::Class> class_array_class =
+      GetClassRoot<mirror::ObjectArray<mirror::Class>>(linker);
+  ObjPtr<mirror::ObjectArray<mirror::Class>> ifaces =
+      mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class, num_ifaces);
   if (ifaces.IsNull()) {
     DCHECK(soa.Self()->IsExceptionPending());
     return nullptr;
@@ -250,20 +244,21 @@
   // with kActiveTransaction == false.
   DCHECK(!Runtime::Current()->IsActiveTransaction());
 
-  ClassLinker* linker = Runtime::Current()->GetClassLinker();
-  MutableHandle<mirror::Class> interface(hs.NewHandle<mirror::Class>(nullptr));
   for (uint32_t i = 0; i < num_ifaces; ++i) {
     const dex::TypeIndex type_idx = iface_list->GetTypeItem(i).type_idx_;
-    interface.Assign(linker->LookupResolvedType(type_idx, klass.Get()));
-    ifaces->SetWithoutChecks<false>(i, interface.Get());
+    ObjPtr<mirror::Class> interface = linker->LookupResolvedType(type_idx, klass.Get());
+    DCHECK(interface != nullptr);
+    ifaces->SetWithoutChecks<false>(i, interface);
   }
 
-  return soa.AddLocalReference<jobjectArray>(ifaces.Get());
+  return soa.AddLocalReference<jobjectArray>(ifaces);
 }
 
-static mirror::ObjectArray<mirror::Field>* GetDeclaredFields(
-    Thread* self, ObjPtr<mirror::Class> klass, bool public_only, bool force_resolve)
-      REQUIRES_SHARED(Locks::mutator_lock_) {
+static ObjPtr<mirror::ObjectArray<mirror::Field>> GetDeclaredFields(
+    Thread* self,
+    ObjPtr<mirror::Class> klass,
+    bool public_only,
+    bool force_resolve) REQUIRES_SHARED(Locks::mutator_lock_) {
   StackHandleScope<1> hs(self);
   IterationRange<StrideIterator<ArtField>> ifields = klass->GetIFields();
   IterationRange<StrideIterator<ArtField>> sfields = klass->GetSFields();
@@ -672,10 +667,8 @@
       // Pending exception from GetDeclaredClasses.
       return nullptr;
     }
-    ObjPtr<mirror::Class> class_array_class = GetClassArrayClass(soa.Self());
-    if (class_array_class == nullptr) {
-      return nullptr;
-    }
+    ObjPtr<mirror::Class> class_array_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>();
+    DCHECK(class_array_class != nullptr);
     ObjPtr<mirror::ObjectArray<mirror::Class>> empty_array =
         mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class, 0);
     return soa.AddLocalReference<jobjectArray>(empty_array);
diff --git a/runtime/native/java_lang_VMClassLoader.cc b/runtime/native/java_lang_VMClassLoader.cc
index b1511c0..42c7ad5 100644
--- a/runtime/native/java_lang_VMClassLoader.cc
+++ b/runtime/native/java_lang_VMClassLoader.cc
@@ -37,11 +37,11 @@
 // A class so we can be friends with ClassLinker and access internal methods.
 class VMClassLoader {
  public:
-  static mirror::Class* LookupClass(ClassLinker* cl,
-                                    Thread* self,
-                                    const char* descriptor,
-                                    size_t hash,
-                                    ObjPtr<mirror::ClassLoader> class_loader)
+  static ObjPtr<mirror::Class> LookupClass(ClassLinker* cl,
+                                           Thread* self,
+                                           const char* descriptor,
+                                           size_t hash,
+                                           ObjPtr<mirror::ClassLoader> class_loader)
       REQUIRES(!Locks::classlinker_classes_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_) {
     return cl->LookupClass(self, descriptor, hash, class_loader);
diff --git a/runtime/native/java_lang_reflect_Constructor.cc b/runtime/native/java_lang_reflect_Constructor.cc
index 13a8d28..a961cb2 100644
--- a/runtime/native/java_lang_reflect_Constructor.cc
+++ b/runtime/native/java_lang_reflect_Constructor.cc
@@ -20,8 +20,8 @@
 
 #include "art_method-inl.h"
 #include "base/enums.h"
-#include "class_linker-inl.h"
 #include "class_linker.h"
+#include "class_root.h"
 #include "dex/dex_file_annotations.h"
 #include "jni/jni_internal.h"
 #include "mirror/class-inl.h"
@@ -42,12 +42,8 @@
       annotations::GetExceptionTypesForMethod(method);
   if (result_array == nullptr) {
     // Return an empty array instead of a null pointer.
-    ObjPtr<mirror::Class> class_class = mirror::Class::GetJavaLangClass();
-    ObjPtr<mirror::Class> class_array_class =
-        Runtime::Current()->GetClassLinker()->FindArrayClass(soa.Self(), &class_class);
-    if (class_array_class == nullptr) {
-      return nullptr;
-    }
+    ObjPtr<mirror::Class> class_array_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>();
+    DCHECK(class_array_class != nullptr);
     ObjPtr<mirror::ObjectArray<mirror::Class>> empty_array =
         mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class, 0);
     return soa.AddLocalReference<jobjectArray>(empty_array);
diff --git a/runtime/native/java_lang_reflect_Executable.cc b/runtime/native/java_lang_reflect_Executable.cc
index 9a2d302..a40cb9b 100644
--- a/runtime/native/java_lang_reflect_Executable.cc
+++ b/runtime/native/java_lang_reflect_Executable.cc
@@ -20,6 +20,7 @@
 #include "nativehelper/jni_macros.h"
 
 #include "art_method-inl.h"
+#include "class_root.h"
 #include "dex/dex_file_annotations.h"
 #include "handle.h"
 #include "jni/jni_internal.h"
@@ -335,15 +336,6 @@
   return soa.AddLocalReference<jclass>(return_type);
 }
 
-// TODO: Move this to mirror::Class ? Other mirror types that commonly appear
-// as arrays have a GetArrayClass() method. This is duplicated in
-// java_lang_Class.cc as well.
-static ObjPtr<mirror::Class> GetClassArrayClass(Thread* self)
-    REQUIRES_SHARED(Locks::mutator_lock_) {
-  ObjPtr<mirror::Class> class_class = mirror::Class::GetJavaLangClass();
-  return Runtime::Current()->GetClassLinker()->FindArrayClass(self, &class_class);
-}
-
 static jobjectArray Executable_getParameterTypesInternal(JNIEnv* env, jobject javaMethod) {
   ScopedFastNativeObjectAccess soa(env);
   ArtMethod* method = ArtMethod::FromReflectedMethod(soa, javaMethod);
@@ -356,10 +348,10 @@
 
   const uint32_t num_params = params->Size();
 
-  StackHandleScope<3> hs(soa.Self());
-  Handle<mirror::Class> class_array_class = hs.NewHandle(GetClassArrayClass(soa.Self()));
+  StackHandleScope<2> hs(soa.Self());
+  ObjPtr<mirror::Class> class_array_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>();
   Handle<mirror::ObjectArray<mirror::Class>> ptypes = hs.NewHandle(
-      mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class.Get(), num_params));
+      mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class, num_params));
   if (ptypes.IsNull()) {
     DCHECK(soa.Self()->IsExceptionPending());
     return nullptr;
diff --git a/runtime/native/java_lang_reflect_Method.cc b/runtime/native/java_lang_reflect_Method.cc
index 52e0494..34455fe 100644
--- a/runtime/native/java_lang_reflect_Method.cc
+++ b/runtime/native/java_lang_reflect_Method.cc
@@ -22,6 +22,7 @@
 #include "base/enums.h"
 #include "class_linker-inl.h"
 #include "class_linker.h"
+#include "class_root.h"
 #include "dex/dex_file_annotations.h"
 #include "jni/jni_internal.h"
 #include "mirror/class-inl.h"
@@ -66,12 +67,8 @@
         annotations::GetExceptionTypesForMethod(method);
     if (result_array == nullptr) {
       // Return an empty array instead of a null pointer
-      ObjPtr<mirror::Class> class_class = mirror::Class::GetJavaLangClass();
-      ObjPtr<mirror::Class> class_array_class =
-          Runtime::Current()->GetClassLinker()->FindArrayClass(soa.Self(), &class_class);
-      if (class_array_class == nullptr) {
-        return nullptr;
-      }
+      ObjPtr<mirror::Class> class_array_class = GetClassRoot<mirror::ObjectArray<mirror::Class>>();
+      DCHECK(class_array_class != nullptr);
       mirror::ObjectArray<mirror::Class>* empty_array =
           mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class, 0);
       return soa.AddLocalReference<jobjectArray>(empty_array);
diff --git a/runtime/proxy_test.cc b/runtime/proxy_test.cc
index 4e0bf89..946ea01 100644
--- a/runtime/proxy_test.cc
+++ b/runtime/proxy_test.cc
@@ -44,9 +44,9 @@
   ASSERT_TRUE(I != nullptr);
   ASSERT_TRUE(J != nullptr);
 
-  std::vector<mirror::Class*> interfaces;
-  interfaces.push_back(I.Get());
-  interfaces.push_back(J.Get());
+  std::vector<Handle<mirror::Class>> interfaces;
+  interfaces.push_back(I);
+  interfaces.push_back(J);
   Handle<mirror::Class> proxy_class(hs.NewHandle(
       GenerateProxyClass(soa, jclass_loader, class_linker_, "$Proxy1234", interfaces)));
   interfaces.clear();  // Don't least possibly stale objects in the array as good practice.
@@ -80,9 +80,9 @@
 
   Handle<mirror::Class> proxyClass;
   {
-    std::vector<mirror::Class*> interfaces;
-    interfaces.push_back(I.Get());
-    interfaces.push_back(J.Get());
+    std::vector<Handle<mirror::Class>> interfaces;
+    interfaces.push_back(I);
+    interfaces.push_back(J);
     proxyClass = hs.NewHandle(
         GenerateProxyClass(soa, jclass_loader, class_linker_, "$Proxy1234", interfaces));
   }
@@ -131,7 +131,7 @@
   Handle<mirror::Class> proxyClass0;
   Handle<mirror::Class> proxyClass1;
   {
-    std::vector<mirror::Class*> interfaces;
+    std::vector<Handle<mirror::Class>> interfaces;
     proxyClass0 = hs.NewHandle(
         GenerateProxyClass(soa, jclass_loader, class_linker_, "$Proxy0", interfaces));
     proxyClass1 = hs.NewHandle(
diff --git a/runtime/proxy_test.h b/runtime/proxy_test.h
index fa5a449..860d96c 100644
--- a/runtime/proxy_test.h
+++ b/runtime/proxy_test.h
@@ -25,6 +25,7 @@
 #include "class_root.h"
 #include "mirror/class-inl.h"
 #include "mirror/method.h"
+#include "obj_ptr-inl.h"
 
 namespace art {
 namespace proxy_test {
@@ -32,11 +33,11 @@
 // Generate a proxy class with the given name and interfaces. This is a simplification from what
 // libcore does to fit to our test needs. We do not check for duplicated interfaces or methods and
 // we do not declare exceptions.
-mirror::Class* GenerateProxyClass(ScopedObjectAccess& soa,
-                                  jobject jclass_loader,
-                                  ClassLinker* class_linker,
-                                  const char* className,
-                                  const std::vector<mirror::Class*>& interfaces)
+ObjPtr<mirror::Class> GenerateProxyClass(ScopedObjectAccess& soa,
+                                         jobject jclass_loader,
+                                         ClassLinker* class_linker,
+                                         const char* className,
+                                         const std::vector<Handle<mirror::Class>>& interfaces)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   StackHandleScope<1> hs(soa.Self());
   Handle<mirror::Class> javaLangObject = hs.NewHandle(
@@ -46,21 +47,23 @@
   jclass javaLangClass = soa.AddLocalReference<jclass>(mirror::Class::GetJavaLangClass());
 
   // Builds the interfaces array.
-  jobjectArray proxyClassInterfaces = soa.Env()->NewObjectArray(interfaces.size(), javaLangClass,
-                                                                nullptr);
+  jobjectArray proxyClassInterfaces =
+      soa.Env()->NewObjectArray(interfaces.size(), javaLangClass, /* initialElement */ nullptr);
   soa.Self()->AssertNoPendingException();
   for (size_t i = 0; i < interfaces.size(); ++i) {
     soa.Env()->SetObjectArrayElement(proxyClassInterfaces, i,
-                                     soa.AddLocalReference<jclass>(interfaces[i]));
+                                     soa.AddLocalReference<jclass>(interfaces[i].Get()));
   }
 
   // Builds the method array.
   jsize methods_count = 3;  // Object.equals, Object.hashCode and Object.toString.
-  for (mirror::Class* interface : interfaces) {
+  for (Handle<mirror::Class> interface : interfaces) {
     methods_count += interface->NumVirtualMethods();
   }
   jobjectArray proxyClassMethods = soa.Env()->NewObjectArray(
-      methods_count, soa.AddLocalReference<jclass>(GetClassRoot<mirror::Method>()), nullptr);
+      methods_count,
+      soa.AddLocalReference<jclass>(GetClassRoot<mirror::Method>()),
+      /* initialElement */ nullptr);
   soa.Self()->AssertNoPendingException();
 
   jsize array_index = 0;
@@ -91,7 +94,7 @@
       proxyClassMethods, array_index++, soa.AddLocalReference<jobject>(
           mirror::Method::CreateFromArtMethod<kRuntimePointerSize, false>(soa.Self(), method)));
   // Now adds all interfaces virtual methods.
-  for (mirror::Class* interface : interfaces) {
+  for (Handle<mirror::Class> interface : interfaces) {
     for (auto& m : interface->GetDeclaredVirtualMethods(kRuntimePointerSize)) {
       soa.Env()->SetObjectArrayElement(
           proxyClassMethods, array_index++, soa.AddLocalReference<jobject>(
@@ -104,9 +107,13 @@
   jobjectArray proxyClassThrows = soa.Env()->NewObjectArray(0, javaLangClass, nullptr);
   soa.Self()->AssertNoPendingException();
 
-  mirror::Class* proxyClass = class_linker->CreateProxyClass(
-      soa, soa.Env()->NewStringUTF(className), proxyClassInterfaces, jclass_loader,
-      proxyClassMethods, proxyClassThrows);
+  ObjPtr<mirror::Class> proxyClass = class_linker->CreateProxyClass(
+      soa,
+      soa.Env()->NewStringUTF(className),
+      proxyClassInterfaces,
+      jclass_loader,
+      proxyClassMethods,
+      proxyClassThrows);
   soa.Self()->AssertNoPendingException();
   return proxyClass;
 }
diff --git a/runtime/reflection_test.cc b/runtime/reflection_test.cc
index d2d720f..424ee06 100644
--- a/runtime/reflection_test.cc
+++ b/runtime/reflection_test.cc
@@ -80,7 +80,7 @@
 
   jclass GetPrimitiveClass(char descriptor) {
     ScopedObjectAccess soa(env_);
-    mirror::Class* c = class_linker_->FindPrimitiveClass(descriptor);
+    ObjPtr<mirror::Class> c = class_linker_->FindPrimitiveClass(descriptor);
     CHECK(c != nullptr);
     return soa.AddLocalReference<jclass>(c);
   }
@@ -518,7 +518,7 @@
       hs.NewHandle(soa.Decode<mirror::ClassLoader>(jclass_loader)));
   CompileDirectMethod(class_loader, "Main", "main", "([Ljava/lang/String;)V");
 
-  mirror::Class* klass = class_linker_->FindClass(soa.Self(), "LMain;", class_loader);
+  ObjPtr<mirror::Class> klass = class_linker_->FindClass(soa.Self(), "LMain;", class_loader);
   ASSERT_TRUE(klass != nullptr);
 
   ArtMethod* method = klass->FindClassMethod("main",
diff --git a/runtime/thread.cc b/runtime/thread.cc
index ab1a4bb..b59606a 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -2862,27 +2862,18 @@
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
 
   StackHandleScope<6> hs(soa.Self());
-  mirror::Class* aste_array_class = class_linker->FindClass(
+  Handle<mirror::Class> h_aste_array_class = hs.NewHandle(class_linker->FindSystemClass(
       soa.Self(),
-      "[Ldalvik/system/AnnotatedStackTraceElement;",
-      ScopedNullHandle<mirror::ClassLoader>());
-  if (aste_array_class == nullptr) {
+      "[Ldalvik/system/AnnotatedStackTraceElement;"));
+  if (h_aste_array_class == nullptr) {
     return nullptr;
   }
-  Handle<mirror::Class> h_aste_array_class(hs.NewHandle<mirror::Class>(aste_array_class));
+  Handle<mirror::Class> h_aste_class = hs.NewHandle(h_aste_array_class->GetComponentType());
 
-  mirror::Class* o_array_class = class_linker->FindClass(soa.Self(),
-                                                         "[Ljava/lang/Object;",
-                                                         ScopedNullHandle<mirror::ClassLoader>());
-  if (o_array_class == nullptr) {
-    // This should not fail in a healthy runtime.
-    soa.Self()->AssertPendingException();
-    return nullptr;
-  }
-  Handle<mirror::Class> h_o_array_class(hs.NewHandle<mirror::Class>(o_array_class));
+  Handle<mirror::Class> h_o_array_class =
+      hs.NewHandle(GetClassRoot<mirror::ObjectArray<mirror::Object>>(class_linker));
+  DCHECK(h_o_array_class != nullptr);  // Class roots must be already initialized.
 
-  Handle<mirror::Class> h_aste_class(hs.NewHandle<mirror::Class>(
-      h_aste_array_class->GetComponentType()));
 
   // Make sure the AnnotatedStackTraceElement.class is initialized, b/76208924 .
   class_linker->EnsureInitialized(soa.Self(),
@@ -2906,7 +2897,7 @@
 
   size_t length = dumper.stack_trace_elements_.size();
   ObjPtr<mirror::ObjectArray<mirror::Object>> array =
-      mirror::ObjectArray<mirror::Object>::Alloc(soa.Self(), aste_array_class, length);
+      mirror::ObjectArray<mirror::Object>::Alloc(soa.Self(), h_aste_array_class.Get(), length);
   if (array == nullptr) {
     soa.Self()->AssertPendingOOMException();
     return nullptr;
diff --git a/runtime/verifier/method_verifier.cc b/runtime/verifier/method_verifier.cc
index cc71dc5..2e3a659 100644
--- a/runtime/verifier/method_verifier.cc
+++ b/runtime/verifier/method_verifier.cc
@@ -144,7 +144,7 @@
 }
 
 FailureKind MethodVerifier::VerifyClass(Thread* self,
-                                        mirror::Class* klass,
+                                        ObjPtr<mirror::Class> klass,
                                         CompilerCallbacks* callbacks,
                                         bool allow_soft_failures,
                                         HardFailLogMode log_level,
diff --git a/runtime/verifier/method_verifier.h b/runtime/verifier/method_verifier.h
index b2adc62..ae7481c 100644
--- a/runtime/verifier/method_verifier.h
+++ b/runtime/verifier/method_verifier.h
@@ -96,7 +96,7 @@
  public:
   // Verify a class. Returns "kNoFailure" on success.
   static FailureKind VerifyClass(Thread* self,
-                                 mirror::Class* klass,
+                                 ObjPtr<mirror::Class> klass,
                                  CompilerCallbacks* callbacks,
                                  bool allow_soft_failures,
                                  HardFailLogMode log_level,
diff --git a/runtime/verifier/method_verifier_test.cc b/runtime/verifier/method_verifier_test.cc
index db3f093..d1be9fa 100644
--- a/runtime/verifier/method_verifier_test.cc
+++ b/runtime/verifier/method_verifier_test.cc
@@ -37,7 +37,7 @@
       REQUIRES_SHARED(Locks::mutator_lock_) {
     ASSERT_TRUE(descriptor != nullptr);
     Thread* self = Thread::Current();
-    mirror::Class* klass = class_linker_->FindSystemClass(self, descriptor.c_str());
+    ObjPtr<mirror::Class> klass = class_linker_->FindSystemClass(self, descriptor.c_str());
 
     // Verify the class
     std::string error_msg;