/*
* 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 "builder.h"
#include "code_generator.h"
#include "dex_file.h"
#include "dex_instruction.h"
#include "nodes.h"
#include "optimizing_unit_test.h"
#include "ssa_liveness_analysis.h"
#include "utils/arena_allocator.h"
#include "gtest/gtest.h"
namespace art {
static HGraph* BuildGraph(const uint16_t* data, ArenaAllocator* allocator) {
HGraphBuilder builder(allocator);
const DexFile::CodeItem* item = reinterpret_cast<const DexFile::CodeItem*>(data);
HGraph* graph = builder.BuildGraph(*item);
graph->BuildDominatorTree();
graph->TransformToSSA();
graph->FindNaturalLoops();
return graph;
}
TEST(LiveRangesTest, CFG1) {
/*
* Test the following snippet:
* return 0;
*
* Which becomes the following graph (numbered by lifetime position):
* 2: constant0
* 4: goto
* |
* 8: return
* |
* 12: exit
*/
const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
Instruction::CONST_4 | 0 | 0,
Instruction::RETURN);
ArenaPool pool;
ArenaAllocator allocator(&pool);
HGraph* graph = BuildGraph(data, &allocator);
CodeGenerator* codegen = CodeGenerator::Create(&allocator, graph, InstructionSet::kX86);
SsaLivenessAnalysis liveness(*graph, codegen);
liveness.Analyze();
LiveInterval* interval = liveness.GetInstructionFromSsaIndex(0)->GetLiveInterval();
LiveRange* range = interval->GetFirstRange();
ASSERT_EQ(2u, range->GetStart());
// Last use is the return instruction.
ASSERT_EQ(9u, range->GetEnd());
HBasicBlock* block = graph->GetBlocks().Get(1);
ASSERT_TRUE(block->GetLastInstruction()->AsReturn() != nullptr);
ASSERT_EQ(8u, block->GetLastInstruction()->GetLifetimePosition());
ASSERT_TRUE(range->GetNext() == nullptr);
}
TEST(LiveRangesTest, CFG2) {
/*
* Test the following snippet:
* var a = 0;
* if (0 == 0) {
* } else {
* }
* return a;
*
* Which becomes the following graph (numbered by lifetime position):
* 2: constant0
* 4: goto
* |
* 8: equal
* 10: if
* / \
* 14: goto 18: goto
* \ /
* 22: return
* |
* 26: exit
*/
const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
Instruction::CONST_4 | 0 | 0,
Instruction::IF_EQ, 3,
Instruction::GOTO | 0x100,
Instruction::RETURN | 0 << 8);
ArenaPool pool;
ArenaAllocator allocator(&pool);
HGraph* graph = BuildGraph(data, &allocator);
CodeGenerator* codegen = CodeGenerator::Create(&allocator, graph, InstructionSet::kX86);
SsaLivenessAnalysis liveness(*graph, codegen);
liveness.Analyze();
LiveInterval* interval = liveness.GetInstructionFromSsaIndex(0)->GetLiveInterval();
LiveRange* range = interval->GetFirstRange();
ASSERT_EQ(2u, range->GetStart());
// Last use is the return instruction.
ASSERT_EQ(23u, range->GetEnd());
HBasicBlock* block = graph->GetBlocks().Get(3);
ASSERT_TRUE(block->GetLastInstruction()->AsReturn() != nullptr);
ASSERT_EQ(22u, block->GetLastInstruction()->GetLifetimePosition());
ASSERT_TRUE(range->GetNext() == nullptr);
}
TEST(LiveRangesTest, CFG3) {
/*
* Test the following snippet:
* var a = 0;
* if (0 == 0) {
* } else {
* a = 4;
* }
* return a;
*
* Which becomes the following graph (numbered by lifetime position):
* 2: constant0
* 4: constant4
* 6: goto
* |
* 10: equal
* 12: if
* / \
* 16: goto 20: goto
* \ /
* 22: phi
* 24: return
* |
* 38: exit
*/
const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
Instruction::CONST_4 | 0 | 0,
Instruction::IF_EQ, 3,
Instruction::CONST_4 | 4 << 12 | 0,
Instruction::RETURN | 0 << 8);
ArenaPool pool;
ArenaAllocator allocator(&pool);
HGraph* graph = BuildGraph(data, &allocator);
CodeGenerator* codegen = CodeGenerator::Create(&allocator, graph, InstructionSet::kX86);
SsaLivenessAnalysis liveness(*graph, codegen);
liveness.Analyze();
// Test for the 4 constant.
LiveInterval* interval = liveness.GetInstructionFromSsaIndex(1)->GetLiveInterval();
LiveRange* range = interval->GetFirstRange();
ASSERT_EQ(4u, range->GetStart());
// Last use is the phi at the return block so instruction is live until
// the end of the then block.
ASSERT_EQ(18u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
// Test for the 0 constant.
interval = liveness.GetInstructionFromSsaIndex(0)->GetLiveInterval();
// The then branch is a hole for this constant, therefore its interval has 2 ranges.
// First range starts from the definition and ends at the if block.
range = interval->GetFirstRange();
ASSERT_EQ(2u, range->GetStart());
// 14 is the end of the if block.
ASSERT_EQ(14u, range->GetEnd());
// Second range is the else block.
range = range->GetNext();
ASSERT_EQ(18u, range->GetStart());
// Last use is the phi at the return block.
ASSERT_EQ(22u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
// Test for the phi.
interval = liveness.GetInstructionFromSsaIndex(2)->GetLiveInterval();
range = interval->GetFirstRange();
ASSERT_EQ(22u, liveness.GetInstructionFromSsaIndex(2)->GetLifetimePosition());
ASSERT_EQ(22u, range->GetStart());
ASSERT_EQ(25u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
}
TEST(LiveRangesTest, Loop) {
/*
* Test the following snippet:
* var a = 0;
* while (a == a) {
* a = 4;
* }
* return 5;
*
* Which becomes the following graph (numbered by lifetime position):
* 2: constant0
* 4: constant4
* 6: constant5
* 8: goto
* |
* 12: goto
* |
* 14: phi
* 16: equal
* 18: if +++++
* | \ +
* | 22: goto
* |
* 26: return
* |
* 30: exit
*/
const uint16_t data[] = TWO_REGISTERS_CODE_ITEM(
Instruction::CONST_4 | 0 | 0,
Instruction::IF_EQ, 4,
Instruction::CONST_4 | 4 << 12 | 0,
Instruction::GOTO | 0xFD00,
Instruction::CONST_4 | 5 << 12 | 1 << 8,
Instruction::RETURN | 1 << 8);
ArenaPool pool;
ArenaAllocator allocator(&pool);
HGraph* graph = BuildGraph(data, &allocator);
CodeGenerator* codegen = CodeGenerator::Create(&allocator, graph, InstructionSet::kX86);
SsaLivenessAnalysis liveness(*graph, codegen);
liveness.Analyze();
// Test for the 0 constant.
LiveInterval* interval = liveness.GetInstructionFromSsaIndex(0)->GetLiveInterval();
LiveRange* range = interval->GetFirstRange();
ASSERT_EQ(2u, range->GetStart());
// Last use is the loop phi so instruction is live until
// the end of the pre loop header.
ASSERT_EQ(14u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
// Test for the 4 constant.
interval = liveness.GetInstructionFromSsaIndex(1)->GetLiveInterval();
range = interval->GetFirstRange();
// The instruction is live until the end of the loop.
ASSERT_EQ(4u, range->GetStart());
ASSERT_EQ(24u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
// Test for the 5 constant.
interval = liveness.GetInstructionFromSsaIndex(2)->GetLiveInterval();
range = interval->GetFirstRange();
// The instruction is live until the return instruction after the loop.
ASSERT_EQ(6u, range->GetStart());
ASSERT_EQ(27u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
// Test for the phi.
interval = liveness.GetInstructionFromSsaIndex(3)->GetLiveInterval();
range = interval->GetFirstRange();
// Instruction is consumed by the if.
ASSERT_EQ(14u, range->GetStart());
ASSERT_EQ(17u, range->GetEnd());
ASSERT_TRUE(range->GetNext() == nullptr);
}
} // namespace art