libartbase/base/arena_allocator_test.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2013 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 "arena_allocator-inl.h"
 #include "arena_bit_vector.h"
 #include "base/common_art_test.h"
 #include "gtest/gtest.h"
 #include "malloc_arena_pool.h"
 #include "memory_tool.h"

 namespace art {

 class ArenaAllocatorTest : public testing::Test {
  protected:
   size_t NumberOfArenas(ArenaAllocator* allocator) {
     size_t result = 0u;
     for (Arena* a = allocator->arena_head_; a != nullptr; a = a->next_) {
       ++result;
     }
     return result;
   }
 };

 TEST_F(ArenaAllocatorTest, Test) {
   MallocArenaPool pool;
   ArenaAllocator allocator(&pool);
   ArenaBitVector bv(&allocator, 10, true);
   bv.SetBit(5);
   EXPECT_EQ(1U, bv.GetStorageSize());
   bv.SetBit(35);
   EXPECT_EQ(2U, bv.GetStorageSize());
 }

 TEST_F(ArenaAllocatorTest, MakeDefined) {
   // Regression test to make sure we mark the allocated area defined.
   MallocArenaPool pool;
   static constexpr size_t kSmallArraySize = 10;
   static constexpr size_t kLargeArraySize = 50;
   uint32_t* small_array;
   {
     // Allocate a small array from an arena and release it.
     ArenaAllocator allocator(&pool);
     small_array = allocator.AllocArray<uint32_t>(kSmallArraySize);
     ASSERT_EQ(0u, small_array[kSmallArraySize - 1u]);
   }
   {
     // Reuse the previous arena and allocate more than previous allocation including red zone.
     ArenaAllocator allocator(&pool);
     uint32_t* large_array = allocator.AllocArray<uint32_t>(kLargeArraySize);
     ASSERT_EQ(0u, large_array[kLargeArraySize - 1u]);
     // Verify that the allocation was made on the same arena.
     ASSERT_EQ(small_array, large_array);
   }
 }

 TEST_F(ArenaAllocatorTest, LargeAllocations) {
   if (arena_allocator::kArenaAllocatorPreciseTracking) {
     printf("WARNING: TEST DISABLED FOR precise arena tracking\n");
     return;
   }

   {
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);
     // Note: Leaving some space for memory tool red zones.
     void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 5 / 8);
     void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 2 / 8);
     ASSERT_NE(alloc1, alloc2);
     ASSERT_EQ(1u, NumberOfArenas(&allocator));
   }
   {
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);
     void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 13 / 16);
     void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 11 / 16);
     ASSERT_NE(alloc1, alloc2);
     ASSERT_EQ(2u, NumberOfArenas(&allocator));
     void* alloc3 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 7 / 16);
     ASSERT_NE(alloc1, alloc3);
     ASSERT_NE(alloc2, alloc3);
     ASSERT_EQ(3u, NumberOfArenas(&allocator));
   }
   {
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);
     void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 13 / 16);
     void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 9 / 16);
     ASSERT_NE(alloc1, alloc2);
     ASSERT_EQ(2u, NumberOfArenas(&allocator));
     // Note: Leaving some space for memory tool red zones.
     void* alloc3 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 5 / 16);
     ASSERT_NE(alloc1, alloc3);
     ASSERT_NE(alloc2, alloc3);
     ASSERT_EQ(2u, NumberOfArenas(&allocator));
   }
   {
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);
     void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 9 / 16);
     void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 13 / 16);
     ASSERT_NE(alloc1, alloc2);
     ASSERT_EQ(2u, NumberOfArenas(&allocator));
     // Note: Leaving some space for memory tool red zones.
     void* alloc3 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 5 / 16);
     ASSERT_NE(alloc1, alloc3);
     ASSERT_NE(alloc2, alloc3);
     ASSERT_EQ(2u, NumberOfArenas(&allocator));
   }
   {
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);
     // Note: Leaving some space for memory tool red zones.
     for (size_t i = 0; i != 15; ++i) {
       // Allocate 15 times from the same arena.
       allocator.Alloc(arena_allocator::kArenaDefaultSize * 1 / 16);
       ASSERT_EQ(i + 1u, NumberOfArenas(&allocator));
       // Allocate a separate arena.
       allocator.Alloc(arena_allocator::kArenaDefaultSize * 17 / 16);
       ASSERT_EQ(i + 2u, NumberOfArenas(&allocator));
     }
   }
 }

 TEST_F(ArenaAllocatorTest, AllocAlignment) {
   MallocArenaPool pool;
   ArenaAllocator allocator(&pool);
   for (size_t iterations = 0; iterations <= 10; ++iterations) {
     for (size_t size = 1; size <= ArenaAllocator::kAlignment + 1; ++size) {
       void* allocation = allocator.Alloc(size);
       EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(allocation))
           << reinterpret_cast<uintptr_t>(allocation);
     }
   }
 }

 TEST_F(ArenaAllocatorTest, ReallocReuse) {
   // Realloc does not reuse arenas when running under sanitization.
   TEST_DISABLED_FOR_MEMORY_TOOL();

   {
     // Case 1: small aligned allocation, aligned extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2;
     void* original_allocation = allocator.Alloc(original_size);

     const size_t new_size = ArenaAllocator::kAlignment * 3;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_EQ(original_allocation, realloc_allocation);
   }

   {
     // Case 2: small aligned allocation, non-aligned extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2;
     void* original_allocation = allocator.Alloc(original_size);

     const size_t new_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_EQ(original_allocation, realloc_allocation);
   }

   {
     // Case 3: small non-aligned allocation, aligned extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
     void* original_allocation = allocator.Alloc(original_size);

     const size_t new_size = ArenaAllocator::kAlignment * 4;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_EQ(original_allocation, realloc_allocation);
   }

   {
     // Case 4: small non-aligned allocation, aligned non-extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
     void* original_allocation = allocator.Alloc(original_size);

     const size_t new_size = ArenaAllocator::kAlignment * 3;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_EQ(original_allocation, realloc_allocation);
   }

   // The next part is brittle, as the default size for an arena is variable, and we don't know about
   // sanitization.

   {
     // Case 5: large allocation, aligned extend into next arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = arena_allocator::kArenaDefaultSize -
         ArenaAllocator::kAlignment * 5;
     void* original_allocation = allocator.Alloc(original_size);

     const size_t new_size = arena_allocator::kArenaDefaultSize + ArenaAllocator::kAlignment * 2;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_NE(original_allocation, realloc_allocation);
   }

   {
     // Case 6: large allocation, non-aligned extend into next arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = arena_allocator::kArenaDefaultSize -
         ArenaAllocator::kAlignment * 4 -
         ArenaAllocator::kAlignment / 2;
     void* original_allocation = allocator.Alloc(original_size);

     const size_t new_size = arena_allocator::kArenaDefaultSize +
         ArenaAllocator::kAlignment * 2 +
         ArenaAllocator::kAlignment / 2;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_NE(original_allocation, realloc_allocation);
   }
 }

 TEST_F(ArenaAllocatorTest, ReallocAlignment) {
   {
     // Case 1: small aligned allocation, aligned extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2;
     void* original_allocation = allocator.Alloc(original_size);
     ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

     const size_t new_size = ArenaAllocator::kAlignment * 3;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

     void* after_alloc = allocator.Alloc(1);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
   }

   {
     // Case 2: small aligned allocation, non-aligned extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2;
     void* original_allocation = allocator.Alloc(original_size);
     ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

     const size_t new_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

     void* after_alloc = allocator.Alloc(1);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
   }

   {
     // Case 3: small non-aligned allocation, aligned extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
     void* original_allocation = allocator.Alloc(original_size);
     ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

     const size_t new_size = ArenaAllocator::kAlignment * 4;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

     void* after_alloc = allocator.Alloc(1);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
   }

   {
     // Case 4: small non-aligned allocation, aligned non-extend inside arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
     void* original_allocation = allocator.Alloc(original_size);
     ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

     const size_t new_size = ArenaAllocator::kAlignment * 3;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

     void* after_alloc = allocator.Alloc(1);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
   }

   // The next part is brittle, as the default size for an arena is variable, and we don't know about
   // sanitization.

   {
     // Case 5: large allocation, aligned extend into next arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = arena_allocator::kArenaDefaultSize -
         ArenaAllocator::kAlignment * 5;
     void* original_allocation = allocator.Alloc(original_size);
     ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

     const size_t new_size = arena_allocator::kArenaDefaultSize + ArenaAllocator::kAlignment * 2;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

     void* after_alloc = allocator.Alloc(1);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
   }

   {
     // Case 6: large allocation, non-aligned extend into next arena.
     MallocArenaPool pool;
     ArenaAllocator allocator(&pool);

     const size_t original_size = arena_allocator::kArenaDefaultSize -
         ArenaAllocator::kAlignment * 4 -
         ArenaAllocator::kAlignment / 2;
     void* original_allocation = allocator.Alloc(original_size);
     ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

     const size_t new_size = arena_allocator::kArenaDefaultSize +
         ArenaAllocator::kAlignment * 2 +
         ArenaAllocator::kAlignment / 2;
     void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

     void* after_alloc = allocator.Alloc(1);
     EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
   }
 }


 }  // namespace art
	/*
	* Copyright (C) 2013 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 "arena_allocator-inl.h"
	#include "arena_bit_vector.h"
	#include "base/common_art_test.h"
	#include "gtest/gtest.h"
	#include "malloc_arena_pool.h"
	#include "memory_tool.h"

	namespace art {

	class ArenaAllocatorTest : public testing::Test {
	protected:
	size_t NumberOfArenas(ArenaAllocator* allocator) {
	size_t result = 0u;
	for (Arena* a = allocator->arena_head_; a != nullptr; a = a->next_) {
	++result;
	}
	return result;
	}
	};

	TEST_F(ArenaAllocatorTest, Test) {
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	ArenaBitVector bv(&allocator, 10, true);
	bv.SetBit(5);
	EXPECT_EQ(1U, bv.GetStorageSize());
	bv.SetBit(35);
	EXPECT_EQ(2U, bv.GetStorageSize());
	}

	TEST_F(ArenaAllocatorTest, MakeDefined) {
	// Regression test to make sure we mark the allocated area defined.
	MallocArenaPool pool;
	static constexpr size_t kSmallArraySize = 10;
	static constexpr size_t kLargeArraySize = 50;
	uint32_t* small_array;
	{
	// Allocate a small array from an arena and release it.
	ArenaAllocator allocator(&pool);
	small_array = allocator.AllocArray<uint32_t>(kSmallArraySize);
	ASSERT_EQ(0u, small_array[kSmallArraySize - 1u]);
	}
	{
	// Reuse the previous arena and allocate more than previous allocation including red zone.
	ArenaAllocator allocator(&pool);
	uint32_t* large_array = allocator.AllocArray<uint32_t>(kLargeArraySize);
	ASSERT_EQ(0u, large_array[kLargeArraySize - 1u]);
	// Verify that the allocation was made on the same arena.
	ASSERT_EQ(small_array, large_array);
	}
	}

	TEST_F(ArenaAllocatorTest, LargeAllocations) {
	if (arena_allocator::kArenaAllocatorPreciseTracking) {
	printf("WARNING: TEST DISABLED FOR precise arena tracking\n");
	return;
	}

	{
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	// Note: Leaving some space for memory tool red zones.
	void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 5 / 8);
	void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 2 / 8);
	ASSERT_NE(alloc1, alloc2);
	ASSERT_EQ(1u, NumberOfArenas(&allocator));
	}
	{
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 13 / 16);
	void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 11 / 16);
	ASSERT_NE(alloc1, alloc2);
	ASSERT_EQ(2u, NumberOfArenas(&allocator));
	void* alloc3 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 7 / 16);
	ASSERT_NE(alloc1, alloc3);
	ASSERT_NE(alloc2, alloc3);
	ASSERT_EQ(3u, NumberOfArenas(&allocator));
	}
	{
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 13 / 16);
	void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 9 / 16);
	ASSERT_NE(alloc1, alloc2);
	ASSERT_EQ(2u, NumberOfArenas(&allocator));
	// Note: Leaving some space for memory tool red zones.
	void* alloc3 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 5 / 16);
	ASSERT_NE(alloc1, alloc3);
	ASSERT_NE(alloc2, alloc3);
	ASSERT_EQ(2u, NumberOfArenas(&allocator));
	}
	{
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	void* alloc1 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 9 / 16);
	void* alloc2 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 13 / 16);
	ASSERT_NE(alloc1, alloc2);
	ASSERT_EQ(2u, NumberOfArenas(&allocator));
	// Note: Leaving some space for memory tool red zones.
	void* alloc3 = allocator.Alloc(arena_allocator::kArenaDefaultSize * 5 / 16);
	ASSERT_NE(alloc1, alloc3);
	ASSERT_NE(alloc2, alloc3);
	ASSERT_EQ(2u, NumberOfArenas(&allocator));
	}
	{
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	// Note: Leaving some space for memory tool red zones.
	for (size_t i = 0; i != 15; ++i) {
	// Allocate 15 times from the same arena.
	allocator.Alloc(arena_allocator::kArenaDefaultSize * 1 / 16);
	ASSERT_EQ(i + 1u, NumberOfArenas(&allocator));
	// Allocate a separate arena.
	allocator.Alloc(arena_allocator::kArenaDefaultSize * 17 / 16);
	ASSERT_EQ(i + 2u, NumberOfArenas(&allocator));
	}
	}
	}

	TEST_F(ArenaAllocatorTest, AllocAlignment) {
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);
	for (size_t iterations = 0; iterations <= 10; ++iterations) {
	for (size_t size = 1; size <= ArenaAllocator::kAlignment + 1; ++size) {
	void* allocation = allocator.Alloc(size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(allocation))
	<< reinterpret_cast<uintptr_t>(allocation);
	}
	}
	}

	TEST_F(ArenaAllocatorTest, ReallocReuse) {
	// Realloc does not reuse arenas when running under sanitization.
	TEST_DISABLED_FOR_MEMORY_TOOL();

	{
	// Case 1: small aligned allocation, aligned extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2;
	void* original_allocation = allocator.Alloc(original_size);

	const size_t new_size = ArenaAllocator::kAlignment * 3;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_EQ(original_allocation, realloc_allocation);
	}

	{
	// Case 2: small aligned allocation, non-aligned extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2;
	void* original_allocation = allocator.Alloc(original_size);

	const size_t new_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_EQ(original_allocation, realloc_allocation);
	}

	{
	// Case 3: small non-aligned allocation, aligned extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
	void* original_allocation = allocator.Alloc(original_size);

	const size_t new_size = ArenaAllocator::kAlignment * 4;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_EQ(original_allocation, realloc_allocation);
	}

	{
	// Case 4: small non-aligned allocation, aligned non-extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
	void* original_allocation = allocator.Alloc(original_size);

	const size_t new_size = ArenaAllocator::kAlignment * 3;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_EQ(original_allocation, realloc_allocation);
	}

	// The next part is brittle, as the default size for an arena is variable, and we don't know about
	// sanitization.

	{
	// Case 5: large allocation, aligned extend into next arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = arena_allocator::kArenaDefaultSize -
	ArenaAllocator::kAlignment * 5;
	void* original_allocation = allocator.Alloc(original_size);

	const size_t new_size = arena_allocator::kArenaDefaultSize + ArenaAllocator::kAlignment * 2;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_NE(original_allocation, realloc_allocation);
	}

	{
	// Case 6: large allocation, non-aligned extend into next arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = arena_allocator::kArenaDefaultSize -
	ArenaAllocator::kAlignment * 4 -
	ArenaAllocator::kAlignment / 2;
	void* original_allocation = allocator.Alloc(original_size);

	const size_t new_size = arena_allocator::kArenaDefaultSize +
	ArenaAllocator::kAlignment * 2 +
	ArenaAllocator::kAlignment / 2;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_NE(original_allocation, realloc_allocation);
	}
	}

	TEST_F(ArenaAllocatorTest, ReallocAlignment) {
	{
	// Case 1: small aligned allocation, aligned extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2;
	void* original_allocation = allocator.Alloc(original_size);
	ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

	const size_t new_size = ArenaAllocator::kAlignment * 3;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

	void* after_alloc = allocator.Alloc(1);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
	}

	{
	// Case 2: small aligned allocation, non-aligned extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2;
	void* original_allocation = allocator.Alloc(original_size);
	ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

	const size_t new_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

	void* after_alloc = allocator.Alloc(1);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
	}

	{
	// Case 3: small non-aligned allocation, aligned extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
	void* original_allocation = allocator.Alloc(original_size);
	ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

	const size_t new_size = ArenaAllocator::kAlignment * 4;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

	void* after_alloc = allocator.Alloc(1);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
	}

	{
	// Case 4: small non-aligned allocation, aligned non-extend inside arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = ArenaAllocator::kAlignment * 2 + (ArenaAllocator::kAlignment / 2);
	void* original_allocation = allocator.Alloc(original_size);
	ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

	const size_t new_size = ArenaAllocator::kAlignment * 3;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

	void* after_alloc = allocator.Alloc(1);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
	}

	// The next part is brittle, as the default size for an arena is variable, and we don't know about
	// sanitization.

	{
	// Case 5: large allocation, aligned extend into next arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = arena_allocator::kArenaDefaultSize -
	ArenaAllocator::kAlignment * 5;
	void* original_allocation = allocator.Alloc(original_size);
	ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

	const size_t new_size = arena_allocator::kArenaDefaultSize + ArenaAllocator::kAlignment * 2;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

	void* after_alloc = allocator.Alloc(1);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
	}

	{
	// Case 6: large allocation, non-aligned extend into next arena.
	MallocArenaPool pool;
	ArenaAllocator allocator(&pool);

	const size_t original_size = arena_allocator::kArenaDefaultSize -
	ArenaAllocator::kAlignment * 4 -
	ArenaAllocator::kAlignment / 2;
	void* original_allocation = allocator.Alloc(original_size);
	ASSERT_TRUE(IsAligned<ArenaAllocator::kAlignment>(original_allocation));

	const size_t new_size = arena_allocator::kArenaDefaultSize +
	ArenaAllocator::kAlignment * 2 +
	ArenaAllocator::kAlignment / 2;
	void* realloc_allocation = allocator.Realloc(original_allocation, original_size, new_size);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(realloc_allocation));

	void* after_alloc = allocator.Alloc(1);
	EXPECT_TRUE(IsAligned<ArenaAllocator::kAlignment>(after_alloc));
	}
	}


	} // namespace art