runtime/stack_indirect_reference_table_test.cc

/*
 * Copyright (C) 2014 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 "stack_indirect_reference_table.h"
#include "gtest/gtest.h"

namespace art {

// Test the offsets computed for members of StackIndirectReferenceTable. Because of cross-compiling
// it is impossible the use OFFSETOF_MEMBER, so we do some reasonable computations ourselves. This
// test checks whether we do the right thing.
TEST(StackIndirectReferenceTableTest, Offsets) {
  // As the members of StackIndirectReferenceTable are private, we cannot use OFFSETOF_MEMBER
  // here. So do the inverse: set some data, and access it through pointers created from the offsets.

  StackIndirectReferenceTable test_table(reinterpret_cast<mirror::Object*>(0x1234));
  test_table.SetLink(reinterpret_cast<StackIndirectReferenceTable*>(0x5678));
  test_table.SetNumberOfReferences(0x9ABC);

  byte* table_base_ptr = reinterpret_cast<byte*>(&test_table);

  {
    uintptr_t* link_ptr = reinterpret_cast<uintptr_t*>(table_base_ptr +
        StackIndirectReferenceTable::LinkOffset(kPointerSize));
    EXPECT_EQ(*link_ptr, static_cast<size_t>(0x5678));
  }

  {
    uint32_t* num_ptr = reinterpret_cast<uint32_t*>(table_base_ptr +
        StackIndirectReferenceTable::NumberOfReferencesOffset(kPointerSize));
    EXPECT_EQ(*num_ptr, static_cast<size_t>(0x9ABC));
  }

  {
    // Assume sizeof(StackReference<mirror::Object>) == sizeof(uint32_t)
    // TODO: How can we make this assumption-less but still access directly and fully?
    EXPECT_EQ(sizeof(StackReference<mirror::Object>), sizeof(uint32_t));

    uint32_t* ref_ptr = reinterpret_cast<uint32_t*>(table_base_ptr +
        StackIndirectReferenceTable::ReferencesOffset(kPointerSize));
    EXPECT_EQ(*ref_ptr, static_cast<uint32_t>(0x1234));
  }
}

}  // namespace art