BytecodeSequence::BytecodeSequence(CodeBlock* codeBlock)
{
StringPrintStream out;
for (unsigned i = 0; i < codeBlock->numberOfArgumentValueProfiles(); ++i) {
ConcurrentJSLocker locker(codeBlock->m_lock);
CString description = codeBlock->valueProfileForArgument(i)->briefDescription(locker);
if (!description.length())
continue;
out.reset();
out.print("arg", i, ": ", description);
m_header.append(out.toCString());
}
StubInfoMap stubInfos;
codeBlock->getStubInfoMap(stubInfos);
for (unsigned bytecodeIndex = 0; bytecodeIndex < codeBlock->instructions().size();) {
out.reset();
codeBlock->dumpBytecode(out, bytecodeIndex, stubInfos);
m_sequence.append(Bytecode(bytecodeIndex, codeBlock->vm()->interpreter->getOpcodeID(codeBlock->instructions()[bytecodeIndex].u.opcode), out.toCString()));
bytecodeIndex += opcodeLength(
codeBlock->vm()->interpreter->getOpcodeID(
codeBlock->instructions()[bytecodeIndex].u.opcode));
}
}
BytecodeSequence::BytecodeSequence(CodeBlock* codeBlock)
{
StringPrintStream out;
#if ENABLE(VALUE_PROFILER)
for (unsigned i = 0; i < codeBlock->numberOfArgumentValueProfiles(); ++i) {
CString description = codeBlock->valueProfileForArgument(i)->briefDescription();
if (!description.length())
continue;
out.reset();
out.print("arg", i, " (r", argumentToOperand(i), "): ", description);
m_header.append(out.toCString());
}
#endif // ENABLE(VALUE_PROFILER)
for (unsigned bytecodeIndex = 0; bytecodeIndex < codeBlock->instructions().size();) {
out.reset();
codeBlock->dumpBytecode(out, bytecodeIndex);
m_sequence.append(Bytecode(bytecodeIndex, codeBlock->globalData()->interpreter->getOpcodeID(codeBlock->instructions()[bytecodeIndex].u.opcode), out.toCString()));
bytecodeIndex += opcodeLength(
codeBlock->globalData()->interpreter->getOpcodeID(
codeBlock->instructions()[bytecodeIndex].u.opcode));
}
}
void BytecodeGeneratorification::run()
{
// We calculate the liveness at each merge point. This gives us the information which registers should be saved and resumed conservatively.
{
GeneratorLivenessAnalysis pass(*this);
pass.run();
}
UnlinkedCodeBlock* codeBlock = m_graph.codeBlock();
BytecodeRewriter rewriter(m_graph);
// Setup the global switch for the generator.
{
unsigned nextToEnterPoint = enterPoint() + opcodeLength(op_enter);
unsigned switchTableIndex = m_graph.codeBlock()->numberOfSwitchJumpTables();
VirtualRegister state = virtualRegisterForArgument(static_cast<int32_t>(JSGeneratorFunction::GeneratorArgument::State));
auto& jumpTable = m_graph.codeBlock()->addSwitchJumpTable();
jumpTable.min = 0;
jumpTable.branchOffsets.resize(m_yields.size() + 1);
jumpTable.branchOffsets.fill(0);
jumpTable.add(0, nextToEnterPoint);
for (unsigned i = 0; i < m_yields.size(); ++i)
jumpTable.add(i + 1, m_yields[i].point);
rewriter.insertFragmentBefore(nextToEnterPoint, [&](BytecodeRewriter::Fragment& fragment) {
fragment.appendInstruction(op_switch_imm, switchTableIndex, nextToEnterPoint, state.offset());
});
}
for (const YieldData& data : m_yields) {
VirtualRegister scope = virtualRegisterForArgument(static_cast<int32_t>(JSGeneratorFunction::GeneratorArgument::Frame));
// Emit save sequence.
rewriter.insertFragmentBefore(data.point, [&](BytecodeRewriter::Fragment& fragment) {
data.liveness.forEachSetBit([&](size_t index) {
VirtualRegister operand = virtualRegisterForLocal(index);
Storage storage = storageForGeneratorLocal(index);
fragment.appendInstruction(
op_put_to_scope,
scope.offset(), // scope
storage.identifierIndex, // identifier
operand.offset(), // value
GetPutInfo(DoNotThrowIfNotFound, LocalClosureVar, InitializationMode::NotInitialization).operand(), // info
m_generatorFrameSymbolTableIndex, // symbol table constant index
storage.scopeOffset.offset() // scope offset
);
});
// Insert op_ret just after save sequence.
fragment.appendInstruction(op_ret, data.argument);
});
// Emit resume sequence.
rewriter.insertFragmentAfter(data.point, [&](BytecodeRewriter::Fragment& fragment) {
data.liveness.forEachSetBit([&](size_t index) {
VirtualRegister operand = virtualRegisterForLocal(index);
Storage storage = storageForGeneratorLocal(index);
UnlinkedValueProfile profile = codeBlock->addValueProfile();
fragment.appendInstruction(
op_get_from_scope,
operand.offset(), // dst
scope.offset(), // scope
storage.identifierIndex, // identifier
GetPutInfo(DoNotThrowIfNotFound, LocalClosureVar, InitializationMode::NotInitialization).operand(), // info
0, // local scope depth
storage.scopeOffset.offset(), // scope offset
profile // profile
);
});
});
// Clip the unnecessary bytecodes.
rewriter.removeBytecode(data.point);
}
rewriter.execute();
}
void run()
{
// Perform modified liveness analysis to determine which locals are live at the merge points.
// This produces the conservative results for the question, "which variables should be saved and resumed?".
runLivenessFixpoint(m_generatorification.graph());
for (YieldData& data : m_generatorification.yields())
data.liveness = getLivenessInfoAtBytecodeOffset(m_generatorification.graph(), data.point + opcodeLength(op_yield));
}
