[webkit-changes] [WebKit/WebKit] 7fc4af: [JSC] Add megamorphic IC for GetByVal

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 7fc4afa7fa3ef47982e03714ab32c834465b1494
      https://github.com/WebKit/WebKit/commit/7fc4afa7fa3ef47982e03714ab32c834465b1494
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-04-26 (Wed, 26 Apr 2023)

  Changed paths:
    A JSTests/microbenchmarks/megamorphic-load-get-by-val.js
    M Source/JavaScriptCore/bytecode/AccessCase.cpp
    M Source/JavaScriptCore/bytecode/AccessCase.h
    M Source/JavaScriptCore/bytecode/GetByStatus.cpp
    M Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp
    M Source/JavaScriptCore/bytecode/Repatch.cpp
    M Source/JavaScriptCore/bytecode/StructureStubInfo.cpp
    M Source/JavaScriptCore/bytecode/StructureStubInfo.h
    M Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h
    M Source/JavaScriptCore/dfg/DFGBackwardsPropagationPhase.cpp
    M Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
    M Source/JavaScriptCore/dfg/DFGClobberize.h
    M Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp
    M Source/JavaScriptCore/dfg/DFGDoesGC.cpp
    M Source/JavaScriptCore/dfg/DFGFixupPhase.cpp
    M Source/JavaScriptCore/dfg/DFGNode.cpp
    M Source/JavaScriptCore/dfg/DFGNode.h
    M Source/JavaScriptCore/dfg/DFGNodeType.h
    M Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp
    M Source/JavaScriptCore/dfg/DFGSafeToExecute.h
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp
    M Source/JavaScriptCore/ftl/FTLCapabilities.cpp
    M Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp
    M Source/JavaScriptCore/jit/AssemblyHelpers.cpp
    M Source/JavaScriptCore/jit/AssemblyHelpers.h
    M Source/JavaScriptCore/jit/JITOperations.cpp
    M Source/JavaScriptCore/jit/JITOperations.h
    M Source/JavaScriptCore/jit/JITPropertyAccess.cpp

  Log Message:
  -----------
  [JSC] Add megamorphic IC for GetByVal
https://bugs.webkit.org/show_bug.cgi?id=255969
rdar://108540415

Reviewed by Alexey Shvayka.

This patch integrates megamorphic IC into GetByVal.

1. GetByVal has IndexedMegamorphicLoad AccessCase. This checks input is an atomic string, and do megamorphic load via IC.
   The rest of the mechanism is pretty much the same to GetById's megamorphic IC.
2. We sample some megamorphic possibility during LLInt, and in Baseline JIT, we accelerate megamorphic IC repatching in
   IC (we almost immediately start generating megamorphic IC).
3. Right now, we disable GetByVal megamorphic IC for enumerator_get_by_val due to its a bit different access patterns compared
   to normal get_by_val. Inherently, it gets so many propertyName string only-once per iteration. So, while it is megamorphic,
   we do not get much benefit until we run this loop again.
4. Add DFG / FTL GetByValMegamorphic node, which is used only when we found lower tier used megamorphic case for this callsite.

    megamorphic-load-get-by-val       68.8591+-1.5779     ^     44.6997+-0.2472        ^ definitely 1.5405x faster

* JSTests/microbenchmarks/megamorphic-load-get-by-val.js: Added.
(f):
* Source/JavaScriptCore/bytecode/AccessCase.cpp:
(JSC::AccessCase::create):
(JSC::AccessCase::guardedByStructureCheckSkippingConstantIdentifierCheck const):
(JSC::AccessCase::requiresIdentifierNameMatch const):
(JSC::AccessCase::requiresInt32PropertyCheck const):
(JSC::AccessCase::needsScratchFPR const):
(JSC::AccessCase::forEachDependentCell const):
(JSC::AccessCase::doesCalls const):
(JSC::AccessCase::canReplace const):
(JSC::AccessCase::runWithDowncast):
(JSC::AccessCase::canBeShared):
* Source/JavaScriptCore/bytecode/AccessCase.h:
* Source/JavaScriptCore/bytecode/GetByStatus.cpp:
(JSC::GetByStatus::computeFromLLInt):
(JSC::GetByStatus::computeForStubInfoWithoutExitSiteFeedback):
* Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp:
(JSC::InlineCacheCompiler::generateWithGuard):
(JSC::InlineCacheCompiler::generateImpl):
(JSC::InlineCacheCompiler::regenerate):
* Source/JavaScriptCore/bytecode/Repatch.cpp:
(JSC::repatchGetBy):
* Source/JavaScriptCore/bytecode/StructureStubInfo.cpp:
(JSC::StructureStubInfo::summary const):
(JSC::StructureStubInfo::initializeFromUnlinkedStructureStubInfo):
(JSC::StructureStubInfo::initializeFromDFGUnlinkedStructureStubInfo):
* Source/JavaScriptCore/bytecode/StructureStubInfo.h:
* Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h:
(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):
* Source/JavaScriptCore/dfg/DFGBackwardsPropagationPhase.cpp:
(JSC::DFG::BackwardsPropagationPhase::propagate):
* Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::parseBlock):
* Source/JavaScriptCore/dfg/DFGClobberize.h:
(JSC::DFG::clobberize):
* Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::foldConstants):
* Source/JavaScriptCore/dfg/DFGDoesGC.cpp:
(JSC::DFG::doesGC):
* Source/JavaScriptCore/dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
* Source/JavaScriptCore/dfg/DFGNode.cpp:
(JSC::DFG::Node::convertToGetByIdMaybeMegamorphic):
(JSC::DFG::Node::convertToGetById): Deleted.
* Source/JavaScriptCore/dfg/DFGNode.h:
(JSC::DFG::Node::hasHeapPrediction):
(JSC::DFG::Node::hasStorageChild const):
(JSC::DFG::Node::storageChildIndex):
(JSC::DFG::Node::hasArrayMode):
* Source/JavaScriptCore/dfg/DFGNodeType.h:
* Source/JavaScriptCore/dfg/DFGOperations.cpp:
(JSC::DFG::JSC_DEFINE_JIT_OPERATION):
* Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp:
* Source/JavaScriptCore/dfg/DFGSafeToExecute.h:
(JSC::DFG::safeToExecute):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h:
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compileGetByVal):
(JSC::DFG::SpeculativeJIT::compile):
(JSC::DFG::SpeculativeJIT::compileGetByIdMegamorphic):
(JSC::DFG::SpeculativeJIT::compileGetByValMegamorphic):
* Source/JavaScriptCore/ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile):
* Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:
(JSC::FTL::DFG::LowerDFGToB3::compileNode):
(JSC::FTL::DFG::LowerDFGToB3::compileGetByIdMegamorphic):
(JSC::FTL::DFG::LowerDFGToB3::compileGetByValMegamorphic):
(JSC::FTL::DFG::LowerDFGToB3::compileGetByValImpl):
* Source/JavaScriptCore/jit/AssemblyHelpers.cpp:
(JSC::AssemblyHelpers::loadMegamorphicProperty):
* Source/JavaScriptCore/jit/AssemblyHelpers.h:
* Source/JavaScriptCore/jit/JITOperations.cpp:
(JSC::JSC_DEFINE_JIT_OPERATION):
* Source/JavaScriptCore/jit/JITOperations.h:
* Source/JavaScriptCore/jit/JITPropertyAccess.cpp:
(JSC::JIT::emit_op_get_by_val):
(JSC::JIT::generateGetByValSlowCase):
(JSC::JIT::emitSlow_op_get_by_val_with_this):
(JSC::JIT::emit_op_enumerator_get_by_val):
(JSC::JIT::emit_op_enumerator_put_by_val):

Canonical link: https://commits.webkit.org/263432@main