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/*
* Copyright (C) 2013, 2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "BytecodeLivenessAnalysis.h"
#include "BytecodeKills.h"
#include "BytecodeLivenessAnalysisInlines.h"
#include "BytecodeUseDef.h"
#include "CodeBlock.h"
#include "FullBytecodeLiveness.h"
#include "HeapInlines.h"
#include "InterpreterInlines.h"
#include "PreciseJumpTargets.h"
namespace JSC {
BytecodeLivenessAnalysis::BytecodeLivenessAnalysis(CodeBlock* codeBlock)
: m_graph(codeBlock, codeBlock->instructions())
{
compute();
}
template<typename Functor>
void BytecodeLivenessAnalysis::computeDefsForBytecodeOffset(CodeBlock* codeBlock, OpcodeID opcodeID, Instruction* instruction, FastBitVector&, const Functor& functor)
{
JSC::computeDefsForBytecodeOffset(codeBlock, opcodeID, instruction, functor);
}
template<typename Functor>
void BytecodeLivenessAnalysis::computeUsesForBytecodeOffset(CodeBlock* codeBlock, OpcodeID opcodeID, Instruction* instruction, FastBitVector&, const Functor& functor)
{
JSC::computeUsesForBytecodeOffset(codeBlock, opcodeID, instruction, functor);
}
void BytecodeLivenessAnalysis::getLivenessInfoAtBytecodeOffset(unsigned bytecodeOffset, FastBitVector& result)
{
BytecodeBasicBlock* block = m_graph.findBasicBlockForBytecodeOffset(bytecodeOffset);
ASSERT(block);
ASSERT(!block->isEntryBlock());
ASSERT(!block->isExitBlock());
result.resize(block->out().numBits());
computeLocalLivenessForBytecodeOffset(m_graph, block, bytecodeOffset, result);
}
bool BytecodeLivenessAnalysis::operandIsLiveAtBytecodeOffset(int operand, unsigned bytecodeOffset)
{
if (operandIsAlwaysLive(operand))
return true;
FastBitVector result;
getLivenessInfoAtBytecodeOffset(bytecodeOffset, result);
return operandThatIsNotAlwaysLiveIsLive(result, operand);
}
FastBitVector BytecodeLivenessAnalysis::getLivenessInfoAtBytecodeOffset(unsigned bytecodeOffset)
{
FastBitVector out;
getLivenessInfoAtBytecodeOffset(bytecodeOffset, out);
return out;
}
void BytecodeLivenessAnalysis::computeFullLiveness(FullBytecodeLiveness& result)
{
FastBitVector out;
CodeBlock* codeBlock = m_graph.codeBlock();
result.m_map.resize(codeBlock->instructions().size());
for (std::unique_ptr<BytecodeBasicBlock>& block : m_graph.basicBlocksInReverseOrder()) {
if (block->isEntryBlock() || block->isExitBlock())
continue;
out = block->out();
for (unsigned i = block->offsets().size(); i--;) {
unsigned bytecodeOffset = block->offsets()[i];
stepOverInstruction(m_graph, bytecodeOffset, out);
result.m_map[bytecodeOffset] = out;
}
}
}
void BytecodeLivenessAnalysis::computeKills(BytecodeKills& result)
{
FastBitVector out;
CodeBlock* codeBlock = m_graph.codeBlock();
result.m_codeBlock = codeBlock;
result.m_killSets = std::make_unique<BytecodeKills::KillSet[]>(codeBlock->instructions().size());
for (std::unique_ptr<BytecodeBasicBlock>& block : m_graph.basicBlocksInReverseOrder()) {
if (block->isEntryBlock() || block->isExitBlock())
continue;
out = block->out();
for (unsigned i = block->offsets().size(); i--;) {
unsigned bytecodeOffset = block->offsets()[i];
stepOverInstruction(
m_graph, bytecodeOffset, out,
[&] (unsigned index) {
// This is for uses.
if (out[index])
return;
result.m_killSets[bytecodeOffset].add(index);
out[index] = true;
},
[&] (unsigned index) {
// This is for defs.
out[index] = false;
});
}
}
}
void BytecodeLivenessAnalysis::dumpResults()
{
CodeBlock* codeBlock = m_graph.codeBlock();
dataLog("\nDumping bytecode liveness for ", *codeBlock, ":\n");
Interpreter* interpreter = codeBlock->vm()->interpreter;
Instruction* instructionsBegin = codeBlock->instructions().begin();
unsigned i = 0;
unsigned numberOfBlocks = m_graph.size();
Vector<FastBitVector> predecessors(numberOfBlocks);
for (BytecodeBasicBlock* block : m_graph)
predecessors[block->index()].resize(numberOfBlocks);
for (BytecodeBasicBlock* block : m_graph) {
for (unsigned j = 0; j < block->successors().size(); j++) {
unsigned blockIndex = block->index();
unsigned successorIndex = block->successors()[j]->index();
predecessors[successorIndex][blockIndex] = true;
}
}
auto dumpBitVector = [] (FastBitVector& bits) {
for (unsigned j = 0; j < bits.numBits(); j++) {
if (bits[j])
dataLogF(" %u", j);
}
};
for (BytecodeBasicBlock* block : m_graph) {
dataLogF("\nBytecode basic block %u: %p (offset: %u, length: %u)\n", i++, block, block->leaderOffset(), block->totalLength());
dataLogF("Predecessors:");
dumpBitVector(predecessors[block->index()]);
dataLogF("\n");
dataLogF("Successors:");
FastBitVector successors;
successors.resize(numberOfBlocks);
for (unsigned j = 0; j < block->successors().size(); j++) {
BytecodeBasicBlock* successor = block->successors()[j];
successors[successor->index()] = true;
}
dumpBitVector(successors); // Dump in sorted order.
dataLogF("\n");
if (block->isEntryBlock()) {
dataLogF("Entry block %p\n", block);
continue;
}
if (block->isExitBlock()) {
dataLogF("Exit block: %p\n", block);
continue;
}
for (unsigned bytecodeOffset = block->leaderOffset(); bytecodeOffset < block->leaderOffset() + block->totalLength();) {
const Instruction* currentInstruction = &instructionsBegin[bytecodeOffset];
dataLogF("Live variables:");
FastBitVector liveBefore = getLivenessInfoAtBytecodeOffset(bytecodeOffset);
dumpBitVector(liveBefore);
dataLogF("\n");
codeBlock->dumpBytecode(WTF::dataFile(), codeBlock->globalObject()->globalExec(), instructionsBegin, currentInstruction);
OpcodeID opcodeID = interpreter->getOpcodeID(instructionsBegin[bytecodeOffset].u.opcode);
unsigned opcodeLength = opcodeLengths[opcodeID];
bytecodeOffset += opcodeLength;
}
dataLogF("Live variables:");
FastBitVector liveAfter = block->out();
dumpBitVector(liveAfter);
dataLogF("\n");
}
}
void BytecodeLivenessAnalysis::compute()
{
runLivenessFixpoint(m_graph);
if (Options::dumpBytecodeLivenessResults())
dumpResults();
}
} // namespace JSC
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