runtime/intern_table_test.cc

/*
 * 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 "intern_table-inl.h"

#include "base/hash_set.h"
#include "common_runtime_test.h"
#include "dex/utf.h"
#include "gc_root-inl.h"
#include "handle_scope-inl.h"
#include "mirror/object.h"
#include "mirror/string.h"
#include "scoped_thread_state_change-inl.h"

namespace art {

class InternTableTest : public CommonRuntimeTest {};

TEST_F(InternTableTest, Intern) {
  ScopedObjectAccess soa(Thread::Current());
  InternTable intern_table;
  StackHandleScope<4> hs(soa.Self());
  Handle<mirror::String> foo_1(hs.NewHandle(intern_table.InternStrong(3, "foo")));
  Handle<mirror::String> foo_2(hs.NewHandle(intern_table.InternStrong(3, "foo")));
  Handle<mirror::String> foo_3(
      hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
  Handle<mirror::String> bar(hs.NewHandle(intern_table.InternStrong(3, "bar")));
  ASSERT_TRUE(foo_1 != nullptr);
  ASSERT_TRUE(foo_2 != nullptr);
  ASSERT_TRUE(foo_3 != nullptr);
  ASSERT_TRUE(bar != nullptr);
  EXPECT_EQ(foo_1.Get(), foo_2.Get());
  EXPECT_TRUE(foo_1->Equals("foo"));
  EXPECT_TRUE(foo_2->Equals("foo"));
  EXPECT_TRUE(foo_3->Equals("foo"));
  EXPECT_NE(foo_1.Get(), bar.Get());
  EXPECT_NE(foo_2.Get(), bar.Get());
  EXPECT_NE(foo_3.Get(), bar.Get());
}

TEST_F(InternTableTest, Size) {
  ScopedObjectAccess soa(Thread::Current());
  InternTable t;
  EXPECT_EQ(0U, t.Size());
  t.InternStrong(3, "foo");
  StackHandleScope<1> hs(soa.Self());
  Handle<mirror::String> foo(
      hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
  t.InternWeak(foo.Get());
  EXPECT_EQ(1U, t.Size());
  t.InternStrong(3, "bar");
  EXPECT_EQ(2U, t.Size());
}

// Check if table indexes match on 64 and 32 bit machines.
// This is done by ensuring hash values are the same on every machine and limited to 32-bit wide.
// Otherwise cross compilation can cause a table to be filled on host using one indexing algorithm
// and later on a device with different sizeof(size_t) can use another indexing algorithm.
// Thus the table may provide wrong data.
TEST_F(InternTableTest, CrossHash) {
  ScopedObjectAccess soa(Thread::Current());
  InternTable t;

  // A string that has a negative hash value.
  ObjPtr<mirror::String> str = mirror::String::AllocFromModifiedUtf8(soa.Self(), "00000000");
  // `String::GetHashCode()` ensures that the stored hash is calculated.
  int32_t hash = str->GetHashCode();
  ASSERT_LT(hash, 0);

  MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
  for (InternTable::Table::InternalTable& table : t.strong_interns_.tables_) {
    // The negative hash value shall be 32-bit wide on every host.
    ASSERT_TRUE(IsUint<32>(table.set_.hashfn_(GcRoot<mirror::String>(str))));
  }
}

class TestPredicate : public IsMarkedVisitor {
 public:
  mirror::Object* IsMarked(mirror::Object* s) override REQUIRES_SHARED(Locks::mutator_lock_) {
    bool erased = false;
    for (auto it = expected_.begin(), end = expected_.end(); it != end; ++it) {
      if (*it == s) {
        expected_.erase(it);
        erased = true;
        break;
      }
    }
    EXPECT_TRUE(erased);
    return nullptr;
  }

  void Expect(const mirror::String* s) {
    expected_.push_back(s);
  }

  ~TestPredicate() {
    EXPECT_EQ(0U, expected_.size());
  }

 private:
  mutable std::vector<const mirror::String*> expected_;
};

TEST_F(InternTableTest, SweepInternTableWeaks) {
  ScopedObjectAccess soa(Thread::Current());
  InternTable t;
  t.InternStrong(3, "foo");
  t.InternStrong(3, "bar");
  StackHandleScope<5> hs(soa.Self());
  Handle<mirror::String> hello(
      hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "hello")));
  Handle<mirror::String> world(
      hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "world")));
  Handle<mirror::String> s0(hs.NewHandle(t.InternWeak(hello.Get())));
  Handle<mirror::String> s1(hs.NewHandle(t.InternWeak(world.Get())));

  EXPECT_EQ(4U, t.Size());

  // We should traverse only the weaks...
  TestPredicate p;
  p.Expect(s0.Get());
  p.Expect(s1.Get());
  {
    ReaderMutexLock mu(soa.Self(), *Locks::heap_bitmap_lock_);
    t.SweepInternTableWeaks(&p);
  }

  EXPECT_EQ(2U, t.Size());

  // Just check that we didn't corrupt the map.
  Handle<mirror::String> still_here(
      hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "still here")));
  t.InternWeak(still_here.Get());
  EXPECT_EQ(3U, t.Size());
}

TEST_F(InternTableTest, ContainsWeak) {
  ScopedObjectAccess soa(Thread::Current());
  auto ContainsWeak = [&](InternTable& t, ObjPtr<mirror::String> s)
      REQUIRES_SHARED(Locks::mutator_lock_) {
    return t.LookupWeak(soa.Self(), s) == s;
  };

  {
    // Strongs are never weak.
    InternTable t;
    StackHandleScope<2> hs(soa.Self());
    Handle<mirror::String> interned_foo_1(hs.NewHandle(t.InternStrong(3, "foo")));
    EXPECT_FALSE(ContainsWeak(t, interned_foo_1.Get()));
    Handle<mirror::String> interned_foo_2(hs.NewHandle(t.InternStrong(3, "foo")));
    EXPECT_FALSE(ContainsWeak(t, interned_foo_2.Get()));
    EXPECT_EQ(interned_foo_1.Get(), interned_foo_2.Get());
  }

  {
    // Weaks are always weak.
    InternTable t;
    StackHandleScope<4> hs(soa.Self());
    Handle<mirror::String> foo_1(
        hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
    Handle<mirror::String> foo_2(
        hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
    EXPECT_NE(foo_1.Get(), foo_2.Get());
    Handle<mirror::String> interned_foo_1(hs.NewHandle(t.InternWeak(foo_1.Get())));
    Handle<mirror::String> interned_foo_2(hs.NewHandle(t.InternWeak(foo_2.Get())));
    EXPECT_TRUE(ContainsWeak(t, interned_foo_2.Get()));
    EXPECT_EQ(interned_foo_1.Get(), interned_foo_2.Get());
  }

  {
    // A weak can be promoted to a strong.
    InternTable t;
    StackHandleScope<3> hs(soa.Self());
    Handle<mirror::String> foo(
        hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
    Handle<mirror::String> interned_foo_1(hs.NewHandle(t.InternWeak(foo.Get())));
    EXPECT_TRUE(ContainsWeak(t, interned_foo_1.Get()));
    Handle<mirror::String> interned_foo_2(hs.NewHandle(t.InternStrong(3, "foo")));
    EXPECT_FALSE(ContainsWeak(t, interned_foo_2.Get()));
    EXPECT_EQ(interned_foo_1.Get(), interned_foo_2.Get());
  }

  {
    // Interning a weak after a strong gets you the strong.
    InternTable t;
    StackHandleScope<3> hs(soa.Self());
    Handle<mirror::String> interned_foo_1(hs.NewHandle(t.InternStrong(3, "foo")));
    EXPECT_FALSE(ContainsWeak(t, interned_foo_1.Get()));
    Handle<mirror::String> foo(
        hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
    Handle<mirror::String> interned_foo_2(hs.NewHandle(t.InternWeak(foo.Get())));
    EXPECT_FALSE(ContainsWeak(t, interned_foo_2.Get()));
    EXPECT_EQ(interned_foo_1.Get(), interned_foo_2.Get());
  }
}

TEST_F(InternTableTest, LookupStrong) {
  ScopedObjectAccess soa(Thread::Current());
  InternTable intern_table;
  StackHandleScope<3> hs(soa.Self());
  Handle<mirror::String> foo(hs.NewHandle(intern_table.InternStrong(3, "foo")));
  Handle<mirror::String> bar(hs.NewHandle(intern_table.InternStrong(3, "bar")));
  Handle<mirror::String> foobar(hs.NewHandle(intern_table.InternStrong(6, "foobar")));
  ASSERT_TRUE(foo != nullptr);
  ASSERT_TRUE(bar != nullptr);
  ASSERT_TRUE(foobar != nullptr);
  ASSERT_TRUE(foo->Equals("foo"));
  ASSERT_TRUE(bar->Equals("bar"));
  ASSERT_TRUE(foobar->Equals("foobar"));
  ASSERT_NE(foo.Get(), bar.Get());
  ASSERT_NE(foo.Get(), foobar.Get());
  ASSERT_NE(bar.Get(), foobar.Get());
  ObjPtr<mirror::String> lookup_foo = intern_table.LookupStrong(soa.Self(), 3, "foo");
  EXPECT_OBJ_PTR_EQ(lookup_foo, foo.Get());
  ObjPtr<mirror::String> lookup_bar = intern_table.LookupStrong(soa.Self(), 3, "bar");
  EXPECT_OBJ_PTR_EQ(lookup_bar, bar.Get());
  ObjPtr<mirror::String> lookup_foobar = intern_table.LookupStrong(soa.Self(), 6, "foobar");
  EXPECT_OBJ_PTR_EQ(lookup_foobar, foobar.Get());
  ObjPtr<mirror::String> lookup_foox = intern_table.LookupStrong(soa.Self(), 4, "foox");
  EXPECT_TRUE(lookup_foox == nullptr);
  ObjPtr<mirror::String> lookup_fooba = intern_table.LookupStrong(soa.Self(), 5, "fooba");
  EXPECT_TRUE(lookup_fooba == nullptr);
  ObjPtr<mirror::String> lookup_foobaR = intern_table.LookupStrong(soa.Self(), 6, "foobaR");
  EXPECT_TRUE(lookup_foobaR == nullptr);
  // Try a hash conflict.
  ASSERT_EQ(ComputeUtf16HashFromModifiedUtf8("foobar", 6),
            ComputeUtf16HashFromModifiedUtf8("foobbS", 6));
  ObjPtr<mirror::String> lookup_foobbS = intern_table.LookupStrong(soa.Self(), 6, "foobbS");
  EXPECT_TRUE(lookup_foobbS == nullptr);
}

TEST_F(InternTableTest, InternStrongFrozenWeak) {
  ScopedObjectAccess soa(Thread::Current());
  InternTable intern_table;
  StackHandleScope<1> hs(soa.Self());
  Handle<mirror::String> foo(
      hs.NewHandle(mirror::String::AllocFromModifiedUtf8(soa.Self(), "foo")));
  ASSERT_TRUE(foo != nullptr);
  ObjPtr<mirror::String> weak_foo = intern_table.InternWeak(foo.Get());
  ASSERT_TRUE(weak_foo == foo.Get());

  intern_table.AddNewTable();

  ObjPtr<mirror::String> strong_foo = intern_table.InternStrong(foo.Get());
  ASSERT_TRUE(strong_foo == foo.Get());
}

}  // namespace art