fourthTier: CheckArrays should be hoisted
https://bugs.webkit.org/show_bug.cgi?id=116353
Source/JavaScriptCore:
Performance neutral. This will be more important when we start depending on CheckArray for flat arrays.
Reviewed by Filip Pizlo.
- dfg/DFGAbstractState.cpp: Add ForwardCheckArray to wherever we had a CheckArray before.
(JSC::DFG::AbstractState::executeEffects):
- dfg/DFGArgumentsSimplificationPhase.cpp:
(JSC::DFG::ArgumentsSimplificationPhase::run):
(JSC::DFG::ArrayMode::isContravenedByStructure): Checks if the ArrayMode derived from a specific Structure
would contradict the ArrayModes that would be filtered by the current ArrayMode. This is used to detect
if any specific CheckStructures would contradict our CheckArray so that we can defer to the CheckStructure's
judgment.
- dfg/DFGByteCodeParser.cpp: Fill in checkArrayHoistingFailed where we previously exited due to a BadIndexingType.
(JSC::DFG::ByteCodeParser::setLocal):
(JSC::DFG::ByteCodeParser::setArgument):
(JSC::DFG::ByteCodeParser::parseBlock):
(JSC::DFG::CSEPhase::checkArrayElimination):
(JSC::DFG::CSEPhase::performNodeCSE):
- dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::foldConstants):
(JSC::DFG::FixupPhase::fixupNode):
(JSC::DFG::Node::hasArrayMode):
- dfg/DFGNodeType.h: New ForwardCheckArray node type.
- dfg/DFGPredictionPropagationPhase.cpp:
(JSC::DFG::PredictionPropagationPhase::propagate):
- dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
- dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
- dfg/DFGTypeCheckHoistingPhase.cpp: Refactored most of TypeCheckHoistingPhase into separate functions, some
of which are now generic to both CheckStructure and CheckArray hoisting while others are specific to one or the
other. Both of the non-zero CheckBallot values must be 1 because we use them as an index into an array of
length 2 inside the VariableAccessData.
(CheckData): Moved structure outside of TypeCheckHoistingPhase so that ArrayTypeCheck and StructureTypeCheck
can access it. Also added new fields for tracking ArrayModes. We need the m_arrayModeIsValid because there
isn't a good sentinel value for "this ArrayMode is invalid and meaningless" like there is for m_structure.
We need m_arrayModeHoistingOkay for when we want to permanently disable hoisting for that particular variable.
(JSC::DFG::CheckData::CheckData):
(JSC::DFG::CheckData::disableCheckArrayHoisting): Helper function for disabling CheckArray hoisting for a
specific CheckData.
(JSC::DFG::TypeCheckHoistingPhase::run): We now do both CheckStructure and CheckArray hoisting, although we prefer
CheckStructure hoisting when given the possibility to do both.
(TypeCheckHoistingPhase):
(JSC::DFG::TypeCheckHoistingPhase::clearVariableVotes): Clears all of the VariableAccessData votes since they
can only have two types of votes at any particular time.
(JSC::DFG::TypeCheckHoistingPhase::identifyRedundantStructureChecks):
(JSC::DFG::TypeCheckHoistingPhase::identifyRedundantArrayChecks): Very similar to identifyRedundantStructureChecks,
but with a few different nodes that are important, namely CheckArray (instead of CheckStructure) and the Arrayify-like
nodes always disable hoisting since they always change the IndexingType.
(JSC::DFG::TypeCheckHoistingPhase::disableHoistingForVariablesWithInsufficientVotes):
(JSC::DFG::TypeCheckHoistingPhase::disableHoistingAcrossOSREntries):
(JSC::DFG::TypeCheckHoistingPhase::disableCheckArrayHoisting): Helper that looks up the CheckData for the
specified variable and disables CheckArray hoisting on it.
(JSC::DFG::TypeCheckHoistingPhase::shouldConsiderForHoisting):
(JSC::DFG::TypeCheckHoistingPhase::noticeStructureCheck):
(JSC::DFG::TypeCheckHoistingPhase::noticeCheckArray):
(JSC::DFG::TypeCheckHoistingPhase::noticeStructureCheckAccountingForArrayMode): We want to take CheckStructure nodes
into account when hoisting CheckArrays, so we make sure that if we contradict what a CheckStructure says then we
give up on hoisting the CheckArray.
(JSC::DFG::ArrayTypeCheck::isValidToHoist):
(ArrayTypeCheck): Structure that houses some of the specifics on how to hoist CheckArrays. This structure
is used a template argument to allow some of the very similar code to statically parameterized and reused
for both CheckStructure and CheckArray hoisting.
(JSC::DFG::ArrayTypeCheck::disableHoisting):
(JSC::DFG::ArrayTypeCheck::isContravenedByValue):
(JSC::DFG::ArrayTypeCheck::hasEnoughVotesToHoist):
(JSC::DFG::ArrayTypeCheck::hoistingPreviouslyFailed):
(JSC::DFG::StructureTypeCheck::isValidToHoist):
(StructureTypeCheck): Same as ArrayTypeCheck, but specific to CheckStructure hoisting.
(JSC::DFG::StructureTypeCheck::disableHoisting):
(JSC::DFG::StructureTypeCheck::isContravenedByValue):
(JSC::DFG::StructureTypeCheck::hasEnoughVotesToHoist):
(JSC::DFG::StructureTypeCheck::hoistingPreviouslyFailed):
- dfg/DFGUnificationPhase.cpp: Added merging of whether or not CheckArray hoisting failed.
(JSC::DFG::UnificationPhase::run):
- dfg/DFGVariableAccessData.h:
(JSC::DFG::VariableAccessData::VariableAccessData):
(JSC::DFG::VariableAccessData::mergeCheckArrayHoistingFailed):
(VariableAccessData):
(JSC::DFG::VariableAccessData::checkArrayHoistingFailed):
LayoutTests:
Added a microbenchmark to JSRegress that specifically targets CheckArray hoisting.
We get a 25% improvement on it.
Reviewed by Filip Pizlo.
- fast/js/regress/check-array-hoisting-expected.txt: Added.
- fast/js/regress/check-array-hoisting.html: Added.
- fast/js/regress/script-tests/check-array-hoisting.js: Added.
(f):
