- Revision
- 243127
- Author
- [email protected]
- Date
- 2019-03-18 19:21:10 -0700 (Mon, 18 Mar 2019)
Log Message
[JSC] Generator should not create JSLexicalEnvironment if it is not necessary
https://bugs.webkit.org/show_bug.cgi?id=195901
Reviewed by Saam Barati.
It is not rare that generators do not need to have any registers to be suspended and resumed.
Since currently we always emit op_create_lexical_environment for generator code, we sometimes
create empty JSLexicalEnvironment while it is not required. We can see that a lot of empty JSLexicalEnvironment
are allocated in RAMification's Basic test.
This patch removes this unnecessary allocation. We introduce op_create_generator_frame_environment, which is
a marker, similar to op_yield. And generatorification phase decides whether we should actually emit op_create_lexical_environment,
based on the result of the analysis in generatorification. This can remove unnecessary JSLexicalEnvironment allocations.
We run RAMification in 6 times, use average of them.
RAMification's Basic in JIT mode shows 1.4% improvement.
ToT
Current: 55076864.00, Peak: 55080960.00
Patched
Current: 54325930.67, Peak: 54329344.00
RAMification's Basic in non-JIT mode shows 5.0% improvement.
ToT
Current: 12485290.67, Peak: 12485290.67
Patched
Current: 11894101.33, Peak: 11894101.33
* bytecode/BytecodeGeneratorification.cpp:
(JSC::BytecodeGeneratorification::BytecodeGeneratorification):
(JSC::BytecodeGeneratorification::generatorFrameData const):
(JSC::BytecodeGeneratorification::run):
* bytecode/BytecodeList.rb:
* bytecode/BytecodeUseDef.h:
(JSC::computeUsesForBytecodeOffset):
(JSC::computeDefsForBytecodeOffset):
* bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::BytecodeGenerator):
* dfg/DFGCapabilities.cpp:
(JSC::DFG::capabilityLevel):
* llint/LowLevelInterpreter.asm:
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (243126 => 243127)
--- trunk/Source/_javascript_Core/ChangeLog 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/ChangeLog 2019-03-19 02:21:10 UTC (rev 243127)
@@ -1,3 +1,46 @@
+2019-03-18 Yusuke Suzuki <[email protected]>
+
+ [JSC] Generator should not create JSLexicalEnvironment if it is not necessary
+ https://bugs.webkit.org/show_bug.cgi?id=195901
+
+ Reviewed by Saam Barati.
+
+ It is not rare that generators do not need to have any registers to be suspended and resumed.
+ Since currently we always emit op_create_lexical_environment for generator code, we sometimes
+ create empty JSLexicalEnvironment while it is not required. We can see that a lot of empty JSLexicalEnvironment
+ are allocated in RAMification's Basic test.
+
+ This patch removes this unnecessary allocation. We introduce op_create_generator_frame_environment, which is
+ a marker, similar to op_yield. And generatorification phase decides whether we should actually emit op_create_lexical_environment,
+ based on the result of the analysis in generatorification. This can remove unnecessary JSLexicalEnvironment allocations.
+
+ We run RAMification in 6 times, use average of them.
+ RAMification's Basic in JIT mode shows 1.4% improvement.
+ ToT
+ Current: 55076864.00, Peak: 55080960.00
+ Patched
+ Current: 54325930.67, Peak: 54329344.00
+
+ RAMification's Basic in non-JIT mode shows 5.0% improvement.
+ ToT
+ Current: 12485290.67, Peak: 12485290.67
+ Patched
+ Current: 11894101.33, Peak: 11894101.33
+
+ * bytecode/BytecodeGeneratorification.cpp:
+ (JSC::BytecodeGeneratorification::BytecodeGeneratorification):
+ (JSC::BytecodeGeneratorification::generatorFrameData const):
+ (JSC::BytecodeGeneratorification::run):
+ * bytecode/BytecodeList.rb:
+ * bytecode/BytecodeUseDef.h:
+ (JSC::computeUsesForBytecodeOffset):
+ (JSC::computeDefsForBytecodeOffset):
+ * bytecompiler/BytecodeGenerator.cpp:
+ (JSC::BytecodeGenerator::BytecodeGenerator):
+ * dfg/DFGCapabilities.cpp:
+ (JSC::DFG::capabilityLevel):
+ * llint/LowLevelInterpreter.asm:
+
2019-03-18 Robin Morisset <[email protected]>
Remove the inline capacity of Operands
Modified: trunk/Source/_javascript_Core/bytecode/BytecodeGeneratorification.cpp (243126 => 243127)
--- trunk/Source/_javascript_Core/bytecode/BytecodeGeneratorification.cpp 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/bytecode/BytecodeGeneratorification.cpp 2019-03-19 02:21:10 UTC (rev 243127)
@@ -55,6 +55,14 @@
public:
typedef Vector<YieldData> Yields;
+ struct GeneratorFrameData {
+ InstructionStream::Offset m_point;
+ VirtualRegister m_dst;
+ VirtualRegister m_scope;
+ VirtualRegister m_symbolTable;
+ VirtualRegister m_initialValue;
+ };
+
BytecodeGeneratorification(BytecodeGenerator& bytecodeGenerator, UnlinkedCodeBlock* codeBlock, InstructionStreamWriter& instructions, SymbolTable* generatorFrameSymbolTable, int generatorFrameSymbolTableIndex)
: m_bytecodeGenerator(bytecodeGenerator)
, m_codeBlock(codeBlock)
@@ -83,6 +91,18 @@
break;
}
+ case op_create_generator_frame_environment: {
+ auto bytecode = instruction->as<OpCreateGeneratorFrameEnvironment>();
+ GeneratorFrameData data;
+ data.m_point = instruction.offset();
+ data.m_dst = bytecode.m_dst;
+ data.m_scope = bytecode.m_scope;
+ data.m_symbolTable = bytecode.m_symbolTable;
+ data.m_initialValue = bytecode.m_initialValue;
+ m_generatorFrameData = WTFMove(data);
+ break;
+ }
+
default:
break;
}
@@ -115,6 +135,11 @@
return m_instructions.at(m_enterPoint);
}
+ Optional<GeneratorFrameData> generatorFrameData() const
+ {
+ return m_generatorFrameData;
+ }
+
const InstructionStream& instructions() const
{
return m_instructions;
@@ -150,6 +175,7 @@
BytecodeGenerator& m_bytecodeGenerator;
InstructionStream::Offset m_enterPoint;
+ Optional<GeneratorFrameData> m_generatorFrameData;
UnlinkedCodeBlock* m_codeBlock;
InstructionStreamWriter& m_instructions;
BytecodeGraph m_graph;
@@ -205,7 +231,7 @@
for (unsigned i = 0; i < m_yields.size(); ++i)
jumpTable.add(i + 1, m_yields[i].point);
- rewriter.insertFragmentBefore(nextToEnterPoint, [&](BytecodeRewriter::Fragment& fragment) {
+ rewriter.insertFragmentBefore(nextToEnterPoint, [&] (BytecodeRewriter::Fragment& fragment) {
fragment.appendInstruction<OpSwitchImm>(switchTableIndex, BoundLabel(nextToEnterPoint.offset()), state);
});
}
@@ -215,7 +241,7 @@
auto instruction = m_instructions.at(data.point);
// Emit save sequence.
- rewriter.insertFragmentBefore(instruction, [&](BytecodeRewriter::Fragment& fragment) {
+ rewriter.insertFragmentBefore(instruction, [&] (BytecodeRewriter::Fragment& fragment) {
data.liveness.forEachSetBit([&](size_t index) {
VirtualRegister operand = virtualRegisterForLocal(index);
Storage storage = storageForGeneratorLocal(index);
@@ -235,7 +261,7 @@
});
// Emit resume sequence.
- rewriter.insertFragmentAfter(instruction, [&](BytecodeRewriter::Fragment& fragment) {
+ rewriter.insertFragmentAfter(instruction, [&] (BytecodeRewriter::Fragment& fragment) {
data.liveness.forEachSetBit([&](size_t index) {
VirtualRegister operand = virtualRegisterForLocal(index);
Storage storage = storageForGeneratorLocal(index);
@@ -255,6 +281,18 @@
rewriter.removeBytecode(instruction);
}
+ if (m_generatorFrameData) {
+ auto instruction = m_instructions.at(m_generatorFrameData->m_point);
+ rewriter.insertFragmentAfter(instruction, [&] (BytecodeRewriter::Fragment& fragment) {
+ if (!m_generatorFrameSymbolTable->scopeSize()) {
+ // This will cause us to put jsUndefined() into the generator frame's scope value.
+ fragment.appendInstruction<OpMov>(m_generatorFrameData->m_dst, m_generatorFrameData->m_initialValue);
+ } else
+ fragment.appendInstruction<OpCreateLexicalEnvironment>(m_generatorFrameData->m_dst, m_generatorFrameData->m_scope, m_generatorFrameData->m_symbolTable, m_generatorFrameData->m_initialValue);
+ });
+ rewriter.removeBytecode(instruction);
+ }
+
rewriter.execute();
}
Modified: trunk/Source/_javascript_Core/bytecode/BytecodeList.rb (243126 => 243127)
--- trunk/Source/_javascript_Core/bytecode/BytecodeList.rb 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/bytecode/BytecodeList.rb 2019-03-19 02:21:10 UTC (rev 243127)
@@ -929,6 +929,14 @@
initialValue: VirtualRegister,
}
+op :create_generator_frame_environment,
+ args: {
+ dst: VirtualRegister,
+ scope: VirtualRegister,
+ symbolTable: VirtualRegister,
+ initialValue: VirtualRegister,
+ }
+
op :get_parent_scope,
args: {
dst: VirtualRegister,
Modified: trunk/Source/_javascript_Core/bytecode/BytecodeUseDef.h (243126 => 243127)
--- trunk/Source/_javascript_Core/bytecode/BytecodeUseDef.h 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/bytecode/BytecodeUseDef.h 2019-03-19 02:21:10 UTC (rev 243127)
@@ -156,7 +156,8 @@
USES(OpNewGeneratorFuncExp, scope)
USES(OpNewAsyncFuncExp, scope)
USES(OpToIndexString, index)
- USES(OpCreateLexicalEnvironment, scope)
+ USES(OpCreateLexicalEnvironment, scope, symbolTable, initialValue)
+ USES(OpCreateGeneratorFrameEnvironment, scope, symbolTable, initialValue)
USES(OpResolveScope, scope)
USES(OpResolveScopeForHoistingFuncDeclInEval, scope)
USES(OpGetFromScope, scope)
@@ -364,6 +365,7 @@
DEFS(OpGetParentScope, dst)
DEFS(OpPushWithScope, dst)
DEFS(OpCreateLexicalEnvironment, dst)
+ DEFS(OpCreateGeneratorFrameEnvironment, dst)
DEFS(OpResolveScope, dst)
DEFS(OpResolveScopeForHoistingFuncDeclInEval, dst)
DEFS(OpStrcat, dst)
Modified: trunk/Source/_javascript_Core/bytecompiler/BytecodeGenerator.cpp (243126 => 243127)
--- trunk/Source/_javascript_Core/bytecompiler/BytecodeGenerator.cpp 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/bytecompiler/BytecodeGenerator.cpp 2019-03-19 02:21:10 UTC (rev 243127)
@@ -422,9 +422,6 @@
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode)) {
// Generator and AsyncFunction never provides "arguments". "arguments" reference will be resolved in an upper generator function scope.
needsArguments = false;
-
- // Generator and AsyncFunction uses the var scope to save and resume its variables. So the lexical scope is always instantiated.
- shouldCaptureSomeOfTheThings = true;
}
if (isGeneratorOrAsyncFunctionWrapperParseMode(parseMode) && needsArguments) {
@@ -490,7 +487,7 @@
if (shouldCaptureSomeOfTheThings)
m_lexicalEnvironmentRegister = addVar();
- if (shouldCaptureSomeOfTheThings || vm.typeProfiler())
+ if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode) || shouldCaptureSomeOfTheThings || vm.typeProfiler())
symbolTableConstantIndex = addConstantValue(functionSymbolTable)->index();
// We can allocate the "var" environment if we don't have default parameter expressions. If we have
@@ -839,10 +836,17 @@
// Set up the lexical environment scope as the generator frame. We store the saved and resumed generator registers into this scope with the symbol keys.
// Since they are symbol keyed, these variables cannot be reached from the usual code.
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode)) {
- ASSERT(m_lexicalEnvironmentRegister);
m_generatorFrameSymbolTable.set(*m_vm, functionSymbolTable);
m_generatorFrameSymbolTableIndex = symbolTableConstantIndex;
- move(generatorFrameRegister(), m_lexicalEnvironmentRegister);
+ if (m_lexicalEnvironmentRegister)
+ move(generatorFrameRegister(), m_lexicalEnvironmentRegister);
+ else {
+ // It would be possible that generator does not need to suspend and resume any registers.
+ // In this case, we would like to avoid creating a lexical environment as much as possible.
+ // op_create_generator_frame_environment is a marker, which is similar to op_yield.
+ // Generatorification inserts lexical environment creation if necessary. Otherwise, we convert it to op_mov frame, `undefined`.
+ OpCreateGeneratorFrameEnvironment::emit(this, generatorFrameRegister(), scopeRegister(), VirtualRegister { symbolTableConstantIndex }, addConstantValue(jsUndefined()));
+ }
emitPutById(generatorRegister(), propertyNames().builtinNames().generatorFramePrivateName(), generatorFrameRegister());
}
Modified: trunk/Source/_javascript_Core/dfg/DFGCapabilities.cpp (243126 => 243127)
--- trunk/Source/_javascript_Core/dfg/DFGCapabilities.cpp 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/dfg/DFGCapabilities.cpp 2019-03-19 02:21:10 UTC (rev 243127)
@@ -281,6 +281,7 @@
return CanCompile;
case op_yield:
+ case op_create_generator_frame_environment:
case llint_program_prologue:
case llint_eval_prologue:
case llint_module_program_prologue:
Modified: trunk/Source/_javascript_Core/llint/LowLevelInterpreter.asm (243126 => 243127)
--- trunk/Source/_javascript_Core/llint/LowLevelInterpreter.asm 2019-03-19 02:05:23 UTC (rev 243126)
+++ trunk/Source/_javascript_Core/llint/LowLevelInterpreter.asm 2019-03-19 02:21:10 UTC (rev 243127)
@@ -1800,6 +1800,11 @@
end)
+llintOp(op_create_generator_frame_environment, OpYield, macro (unused, unused, unused)
+ notSupported()
+end)
+
+
llintOp(op_debug, OpDebug, macro (unused, unused, dispatch)
loadp CodeBlock[cfr], t0
loadi CodeBlock::m_debuggerRequests[t0], t0
