1. 25 Jul, 2013 2 commits
    • oliver@apple.com's avatar
      fourthTier: Add a phase to create loop pre-headers · 5663e31c
      oliver@apple.com authored
      https://bugs.webkit.org/show_bug.cgi?id=118778
      
      Reviewed by Oliver Hunt.
      
      Add a loop pre-header creation phase. Any loop that doesn't already have
      just one predecessor that isn't part of the loop has a pre-header
      prepended. All non-loop predecessors then jump to that pre-header.
      
      Also fix a handful of bugs:
      
      - DFG::Analysis should set m_valid before running the analysis, since that
        makes it easier to use ASSERT(m_valid) in the analysis' methods, which
        may be called by the analysis before the analysis completes. NaturalLoops
        does this with loopsOf().
      
      - NaturalLoops::headerOf() was missing a check for innerMostLoopOf()
        returning 0, since that'll happen if the block isn't in any loop.
      
      - Change BlockInsertionSet to dethread the graph, since anyone using it
        will want to do so.
      
      - Change dethreading to ignore SSA form graphs.
      
      This also adds NaturalLoops::belongsTo(), which I always used in the
      pre-header creation phase. I didn't end up using it but I'll probably use
      it in the near future.
      
      * JavaScriptCore.xcodeproj/project.pbxproj:
      * dfg/DFGAnalysis.h:
      (JSC::DFG::Analysis::computeIfNecessary):
      * dfg/DFGBlockInsertionSet.cpp:
      (JSC::DFG::BlockInsertionSet::execute):
      * dfg/DFGCriticalEdgeBreakingPhase.cpp:
      (JSC::DFG::CriticalEdgeBreakingPhase::breakCriticalEdge):
      * dfg/DFGGraph.cpp:
      (JSC::DFG::Graph::dethread):
      * dfg/DFGLoopPreHeaderCreationPhase.cpp: Added.
      (DFG):
      (LoopPreHeaderCreationPhase):
      (JSC::DFG::LoopPreHeaderCreationPhase::LoopPreHeaderCreationPhase):
      (JSC::DFG::LoopPreHeaderCreationPhase::run):
      (JSC::DFG::performLoopPreHeaderCreation):
      * dfg/DFGLoopPreHeaderCreationPhase.h: Added.
      (DFG):
      * dfg/DFGNaturalLoops.h:
      (NaturalLoop):
      (JSC::DFG::NaturalLoops::headerOf):
      (JSC::DFG::NaturalLoops::innerMostLoopOf):
      (JSC::DFG::NaturalLoops::innerMostOuterLoop):
      (JSC::DFG::NaturalLoops::belongsTo):
      (NaturalLoops):
      * dfg/DFGPlan.cpp:
      (JSC::DFG::Plan::compileInThreadImpl):
      
      Conflicts:
      	Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
      
      git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153279 268f45cc-cd09-0410-ab3c-d52691b4dbfc
      5663e31c
    • oliver@apple.com's avatar
      fourthTier: DFG should have an SSA form for use by FTL · 827d2cf7
      oliver@apple.com authored
      https://bugs.webkit.org/show_bug.cgi?id=118338
      
      Source/JavaScriptCore:
      
      Reviewed by Mark Hahnenberg.
      
      Adds an SSA form to the DFG. We can convert ThreadedCPS form into SSA form
      after breaking critical edges. The conversion algorithm follows Aycock and
      Horspool, and the SSA form itself follows something I've done before, where
      instead of having Phi functions specify input nodes corresponding to block
      predecessors, we instead have Upsilon functions in the predecessors that
      specify which value in that block goes into which subsequent Phi. Upsilons
      don't have to dominate Phis (usually they don't) and they correspond to a
      non-SSA "mov" into the Phi's "variable". This gives all of the good
      properties of SSA, while ensuring that a bunch of CFG transformations don't
      have to be SSA-aware.
      
      So far the only DFG phases that are SSA-aware are DCE and CFA. CFG
      simplification is probably SSA-aware by default, though I haven't tried it.
      Constant folding probably needs a few tweaks, but is likely ready. Ditto
      for CSE, though it's not clear that we'd want to use block-local CSE when
      we could be doing GVN.
      
      Currently only the FTL can generate code from the SSA form, and there is no
      way to convert from SSA to ThreadedCPS or LoadStore. There probably will
      never be such a capability.
      
      In order to handle OSR exit state in the SSA, we place MovHints at Phi
      points. Other than that, you can reconstruct state-at-exit by forward
      propagating MovHints. Note that MovHint is the new SetLocal in SSA.
      SetLocal and GetLocal only survive into SSA if they are on captured
      variables, or in the case of flushes. A "live SetLocal" will be
      NodeMustGenerate and will always correspond to a flush. Computing the
      state-at-exit requires running SSA liveness analysis, OSR availability
      analysis, and flush liveness analysis. The FTL runs all of these prior to
      generating code. While OSR exit continues to be tricky, much of the logic
      is now factored into separate phases and the backend has to do less work
      to reason about what happened outside of the basic block that is being
      lowered.
      
      Conversion from DFG SSA to LLVM SSA is done by ensuring that we generate
      code in depth-first order, thus guaranteeing that a node will always be
      lowered (and hence have a LValue) before any of the blocks dominated by
      that node's block have code generated. For Upsilon/Phi, we just use
      alloca's. We could do something more clever there, but it's probably not
      worth it, at least not now.
      
      Finally, while the SSA form is currently only being converted to LLVM IR,
      there is nothing that prevents us from considering other backends in the
      future - with the caveat that this form is designed to be first lowered to
      a lower-level SSA before actual machine code generation commences. So we
      ought to either use LLVM (the intended path) or we will have to write our
      own SSA low-level backend.
      
      This runs all of the code that the FTL was known to run previously. No
      change in performance for now. But it does open some exciting
      possibilities!
      
      * JavaScriptCore.xcodeproj/project.pbxproj:
      * bytecode/Operands.h:
      (JSC::OperandValueTraits::dump):
      (JSC::Operands::fill):
      (Operands):
      (JSC::Operands::clear):
      (JSC::Operands::operator==):
      * dfg/DFGAbstractState.cpp:
      (JSC::DFG::AbstractState::beginBasicBlock):
      (JSC::DFG::setLiveValues):
      (DFG):
      (JSC::DFG::AbstractState::initialize):
      (JSC::DFG::AbstractState::endBasicBlock):
      (JSC::DFG::AbstractState::executeEffects):
      (JSC::DFG::AbstractState::mergeStateAtTail):
      (JSC::DFG::AbstractState::merge):
      * dfg/DFGAbstractState.h:
      (AbstractState):
      * dfg/DFGAdjacencyList.h:
      (JSC::DFG::AdjacencyList::justOneChild):
      (AdjacencyList):
      * dfg/DFGBasicBlock.cpp: Added.
      (DFG):
      (JSC::DFG::BasicBlock::BasicBlock):
      (JSC::DFG::BasicBlock::~BasicBlock):
      (JSC::DFG::BasicBlock::ensureLocals):
      (JSC::DFG::BasicBlock::isInPhis):
      (JSC::DFG::BasicBlock::isInBlock):
      (JSC::DFG::BasicBlock::removePredecessor):
      (JSC::DFG::BasicBlock::replacePredecessor):
      (JSC::DFG::BasicBlock::dump):
      (JSC::DFG::BasicBlock::SSAData::SSAData):
      (JSC::DFG::BasicBlock::SSAData::~SSAData):
      * dfg/DFGBasicBlock.h:
      (BasicBlock):
      (JSC::DFG::BasicBlock::operator[]):
      (JSC::DFG::BasicBlock::successor):
      (JSC::DFG::BasicBlock::successorForCondition):
      (SSAData):
      * dfg/DFGBasicBlockInlines.h:
      (DFG):
      * dfg/DFGBlockInsertionSet.cpp: Added.
      (DFG):
      (JSC::DFG::BlockInsertionSet::BlockInsertionSet):
      (JSC::DFG::BlockInsertionSet::~BlockInsertionSet):
      (JSC::DFG::BlockInsertionSet::insert):
      (JSC::DFG::BlockInsertionSet::insertBefore):
      (JSC::DFG::BlockInsertionSet::execute):
      * dfg/DFGBlockInsertionSet.h: Added.
      (DFG):
      (BlockInsertionSet):
      * dfg/DFGCFAPhase.cpp:
      (JSC::DFG::CFAPhase::run):
      * dfg/DFGCFGSimplificationPhase.cpp:
      * dfg/DFGCPSRethreadingPhase.cpp:
      (JSC::DFG::CPSRethreadingPhase::canonicalizeLocalsInBlock):
      * dfg/DFGCommon.cpp:
      (WTF::printInternal):
      * dfg/DFGCommon.h:
      (JSC::DFG::doesKill):
      (DFG):
      (JSC::DFG::killStatusForDoesKill):
      * dfg/DFGConstantFoldingPhase.cpp:
      (JSC::DFG::ConstantFoldingPhase::foldConstants):
      (JSC::DFG::ConstantFoldingPhase::isCapturedAtOrAfter):
      * dfg/DFGCriticalEdgeBreakingPhase.cpp: Added.
      (DFG):
      (CriticalEdgeBreakingPhase):
      (JSC::DFG::CriticalEdgeBreakingPhase::CriticalEdgeBreakingPhase):
      (JSC::DFG::CriticalEdgeBreakingPhase::run):
      (JSC::DFG::CriticalEdgeBreakingPhase::breakCriticalEdge):
      (JSC::DFG::performCriticalEdgeBreaking):
      * dfg/DFGCriticalEdgeBreakingPhase.h: Added.
      (DFG):
      * dfg/DFGDCEPhase.cpp:
      (JSC::DFG::DCEPhase::run):
      (JSC::DFG::DCEPhase::findTypeCheckRoot):
      (JSC::DFG::DCEPhase::countNode):
      (DCEPhase):
      (JSC::DFG::DCEPhase::countEdge):
      (JSC::DFG::DCEPhase::eliminateIrrelevantPhantomChildren):
      * dfg/DFGDriver.cpp:
      (JSC::DFG::compile):
      * dfg/DFGEdge.cpp:
      (JSC::DFG::Edge::dump):
      * dfg/DFGEdge.h:
      (JSC::DFG::Edge::Edge):
      (JSC::DFG::Edge::setNode):
      (JSC::DFG::Edge::useKindUnchecked):
      (JSC::DFG::Edge::setUseKind):
      (JSC::DFG::Edge::setProofStatus):
      (JSC::DFG::Edge::willNotHaveCheck):
      (JSC::DFG::Edge::willHaveCheck):
      (Edge):
      (JSC::DFG::Edge::killStatusUnchecked):
      (JSC::DFG::Edge::killStatus):
      (JSC::DFG::Edge::setKillStatus):
      (JSC::DFG::Edge::doesKill):
      (JSC::DFG::Edge::doesNotKill):
      (JSC::DFG::Edge::shift):
      (JSC::DFG::Edge::makeWord):
      * dfg/DFGFixupPhase.cpp:
      (JSC::DFG::FixupPhase::fixupNode):
      * dfg/DFGFlushFormat.cpp: Added.
      (WTF):
      (WTF::printInternal):
      * dfg/DFGFlushFormat.h: Added.
      (DFG):
      (JSC::DFG::resultFor):
      (JSC::DFG::useKindFor):
      (WTF):
      * dfg/DFGFlushLivenessAnalysisPhase.cpp: Added.
      (DFG):
      (FlushLivenessAnalysisPhase):
      (JSC::DFG::FlushLivenessAnalysisPhase::FlushLivenessAnalysisPhase):
      (JSC::DFG::FlushLivenessAnalysisPhase::run):
      (JSC::DFG::FlushLivenessAnalysisPhase::process):
      (JSC::DFG::FlushLivenessAnalysisPhase::setForNode):
      (JSC::DFG::FlushLivenessAnalysisPhase::flushFormat):
      (JSC::DFG::performFlushLivenessAnalysis):
      * dfg/DFGFlushLivenessAnalysisPhase.h: Added.
      (DFG):
      * dfg/DFGGraph.cpp:
      (JSC::DFG::Graph::dump):
      (JSC::DFG::Graph::dumpBlockHeader):
      (DFG):
      (JSC::DFG::Graph::addForDepthFirstSort):
      (JSC::DFG::Graph::getBlocksInDepthFirstOrder):
      * dfg/DFGGraph.h:
      (JSC::DFG::Graph::convertToConstant):
      (JSC::DFG::Graph::valueProfileFor):
      (Graph):
      * dfg/DFGInsertionSet.h:
      (DFG):
      (JSC::DFG::InsertionSet::execute):
      * dfg/DFGLivenessAnalysisPhase.cpp: Added.
      (DFG):
      (LivenessAnalysisPhase):
      (JSC::DFG::LivenessAnalysisPhase::LivenessAnalysisPhase):
      (JSC::DFG::LivenessAnalysisPhase::run):
      (JSC::DFG::LivenessAnalysisPhase::process):
      (JSC::DFG::LivenessAnalysisPhase::addChildUse):
      (JSC::DFG::performLivenessAnalysis):
      * dfg/DFGLivenessAnalysisPhase.h: Added.
      (DFG):
      * dfg/DFGNode.cpp:
      (JSC::DFG::Node::hasVariableAccessData):
      (DFG):
      * dfg/DFGNode.h:
      (DFG):
      (Node):
      (JSC::DFG::Node::hasLocal):
      (JSC::DFG::Node::variableAccessData):
      (JSC::DFG::Node::hasPhi):
      (JSC::DFG::Node::phi):
      (JSC::DFG::Node::takenBlock):
      (JSC::DFG::Node::notTakenBlock):
      (JSC::DFG::Node::successor):
      (JSC::DFG::Node::successorForCondition):
      (JSC::DFG::nodeComparator):
      (JSC::DFG::nodeListDump):
      (JSC::DFG::nodeMapDump):
      * dfg/DFGNodeFlags.cpp:
      (JSC::DFG::dumpNodeFlags):
      * dfg/DFGNodeType.h:
      (DFG):
      * dfg/DFGOSRAvailabilityAnalysisPhase.cpp: Added.
      (DFG):
      (OSRAvailabilityAnalysisPhase):
      (JSC::DFG::OSRAvailabilityAnalysisPhase::OSRAvailabilityAnalysisPhase):
      (JSC::DFG::OSRAvailabilityAnalysisPhase::run):
      (JSC::DFG::performOSRAvailabilityAnalysis):
      * dfg/DFGOSRAvailabilityAnalysisPhase.h: Added.
      (DFG):
      * dfg/DFGPlan.cpp:
      (JSC::DFG::Plan::compileInThreadImpl):
      * dfg/DFGPredictionInjectionPhase.cpp:
      (JSC::DFG::PredictionInjectionPhase::run):
      * dfg/DFGPredictionPropagationPhase.cpp:
      (JSC::DFG::PredictionPropagationPhase::propagate):
      * dfg/DFGSSAConversionPhase.cpp: Added.
      (DFG):
      (SSAConversionPhase):
      (JSC::DFG::SSAConversionPhase::SSAConversionPhase):
      (JSC::DFG::SSAConversionPhase::run):
      (JSC::DFG::SSAConversionPhase::forwardPhiChildren):
      (JSC::DFG::SSAConversionPhase::forwardPhi):
      (JSC::DFG::SSAConversionPhase::forwardPhiEdge):
      (JSC::DFG::SSAConversionPhase::deduplicateChildren):
      (JSC::DFG::SSAConversionPhase::addFlushedLocalOp):
      (JSC::DFG::SSAConversionPhase::addFlushedLocalEdge):
      (JSC::DFG::performSSAConversion):
      * dfg/DFGSSAConversionPhase.h: Added.
      (DFG):
      * dfg/DFGSpeculativeJIT32_64.cpp:
      (JSC::DFG::SpeculativeJIT::compile):
      * dfg/DFGSpeculativeJIT64.cpp:
      (JSC::DFG::SpeculativeJIT::compile):
      * dfg/DFGValidate.cpp:
      (JSC::DFG::Validate::validate):
      (Validate):
      (JSC::DFG::Validate::validateCPS):
      * dfg/DFGVariableAccessData.h:
      (JSC::DFG::VariableAccessData::flushFormat):
      (VariableAccessData):
      * ftl/FTLCapabilities.cpp:
      (JSC::FTL::canCompile):
      * ftl/FTLLowerDFGToLLVM.cpp:
      (JSC::FTL::LowerDFGToLLVM::LowerDFGToLLVM):
      (JSC::FTL::LowerDFGToLLVM::lower):
      (JSC::FTL::LowerDFGToLLVM::createPhiVariables):
      (JSC::FTL::LowerDFGToLLVM::compileBlock):
      (JSC::FTL::LowerDFGToLLVM::compileNode):
      (JSC::FTL::LowerDFGToLLVM::compileUpsilon):
      (LowerDFGToLLVM):
      (JSC::FTL::LowerDFGToLLVM::compilePhi):
      (JSC::FTL::LowerDFGToLLVM::compileJSConstant):
      (JSC::FTL::LowerDFGToLLVM::compileWeakJSConstant):
      (JSC::FTL::LowerDFGToLLVM::compileGetArgument):
      (JSC::FTL::LowerDFGToLLVM::compileGetLocal):
      (JSC::FTL::LowerDFGToLLVM::compileSetLocal):
      (JSC::FTL::LowerDFGToLLVM::compileAdd):
      (JSC::FTL::LowerDFGToLLVM::compileArithSub):
      (JSC::FTL::LowerDFGToLLVM::compileArithMul):
      (JSC::FTL::LowerDFGToLLVM::compileArithDiv):
      (JSC::FTL::LowerDFGToLLVM::compileArithMod):
      (JSC::FTL::LowerDFGToLLVM::compileArithMinOrMax):
      (JSC::FTL::LowerDFGToLLVM::compileArithAbs):
      (JSC::FTL::LowerDFGToLLVM::compileArithNegate):
      (JSC::FTL::LowerDFGToLLVM::compileBitAnd):
      (JSC::FTL::LowerDFGToLLVM::compileBitOr):
      (JSC::FTL::LowerDFGToLLVM::compileBitXor):
      (JSC::FTL::LowerDFGToLLVM::compileBitRShift):
      (JSC::FTL::LowerDFGToLLVM::compileBitLShift):
      (JSC::FTL::LowerDFGToLLVM::compileBitURShift):
      (JSC::FTL::LowerDFGToLLVM::compileUInt32ToNumber):
      (JSC::FTL::LowerDFGToLLVM::compileInt32ToDouble):
      (JSC::FTL::LowerDFGToLLVM::compileGetButterfly):
      (JSC::FTL::LowerDFGToLLVM::compileGetArrayLength):
      (JSC::FTL::LowerDFGToLLVM::compileGetByVal):
      (JSC::FTL::LowerDFGToLLVM::compileGetByOffset):
      (JSC::FTL::LowerDFGToLLVM::compileGetGlobalVar):
      (JSC::FTL::LowerDFGToLLVM::compileCompareEqConstant):
      (JSC::FTL::LowerDFGToLLVM::compileCompareStrictEq):
      (JSC::FTL::LowerDFGToLLVM::compileCompareStrictEqConstant):
      (JSC::FTL::LowerDFGToLLVM::compileCompareLess):
      (JSC::FTL::LowerDFGToLLVM::compileCompareLessEq):
      (JSC::FTL::LowerDFGToLLVM::compileCompareGreater):
      (JSC::FTL::LowerDFGToLLVM::compileCompareGreaterEq):
      (JSC::FTL::LowerDFGToLLVM::compileLogicalNot):
      (JSC::FTL::LowerDFGToLLVM::speculateBackward):
      (JSC::FTL::LowerDFGToLLVM::lowInt32):
      (JSC::FTL::LowerDFGToLLVM::lowCell):
      (JSC::FTL::LowerDFGToLLVM::lowBoolean):
      (JSC::FTL::LowerDFGToLLVM::lowDouble):
      (JSC::FTL::LowerDFGToLLVM::lowJSValue):
      (JSC::FTL::LowerDFGToLLVM::lowStorage):
      (JSC::FTL::LowerDFGToLLVM::speculate):
      (JSC::FTL::LowerDFGToLLVM::speculateBoolean):
      (JSC::FTL::LowerDFGToLLVM::isLive):
      (JSC::FTL::LowerDFGToLLVM::use):
      (JSC::FTL::LowerDFGToLLVM::initializeOSRExitStateForBlock):
      (JSC::FTL::LowerDFGToLLVM::appendOSRExit):
      (JSC::FTL::LowerDFGToLLVM::emitOSRExitCall):
      (JSC::FTL::LowerDFGToLLVM::addExitArgumentForNode):
      (JSC::FTL::LowerDFGToLLVM::linkOSRExitsAndCompleteInitializationBlocks):
      (JSC::FTL::LowerDFGToLLVM::setInt32):
      (JSC::FTL::LowerDFGToLLVM::setJSValue):
      (JSC::FTL::LowerDFGToLLVM::setBoolean):
      (JSC::FTL::LowerDFGToLLVM::setStorage):
      (JSC::FTL::LowerDFGToLLVM::setDouble):
      (JSC::FTL::LowerDFGToLLVM::isValid):
      * ftl/FTLLoweredNodeValue.h: Added.
      (FTL):
      (LoweredNodeValue):
      (JSC::FTL::LoweredNodeValue::LoweredNodeValue):
      (JSC::FTL::LoweredNodeValue::isSet):
      (JSC::FTL::LoweredNodeValue::operator!):
      (JSC::FTL::LoweredNodeValue::value):
      (JSC::FTL::LoweredNodeValue::block):
      * ftl/FTLValueFromBlock.h:
      (JSC::FTL::ValueFromBlock::ValueFromBlock):
      (ValueFromBlock):
      * ftl/FTLValueSource.cpp:
      (JSC::FTL::ValueSource::dump):
      * ftl/FTLValueSource.h:
      
      Source/WTF:
      
      Reviewed by Mark Hahnenberg.
      
      - Extend variadicity of PrintStream and dataLog.
      
      - Give HashSet the ability to add a span of things.
      
      - Give HashSet the ability to == another HashSet.
      
      - Note FIXME's in HashTable concerning copying performance, that affects
        the way that the DFG now uses HashSets and HashMaps.
      
      - Factor out the bulk-insertion logic of JSC::DFG::InsertionSet into
        WTF::Insertion, so that it can be used in more places.
      
      - Create a dumper for lists and maps.
      
      * WTF.xcodeproj/project.pbxproj:
      * wtf/DataLog.h:
      (WTF):
      (WTF::dataLog):
      * wtf/HashSet.h:
      (HashSet):
      (WTF):
      (WTF::::add):
      (WTF::=):
      * wtf/HashTable.h:
      (WTF::::HashTable):
      (WTF::=):
      * wtf/Insertion.h: Added.
      (WTF):
      (Insertion):
      (WTF::Insertion::Insertion):
      (WTF::Insertion::index):
      (WTF::Insertion::element):
      (WTF::Insertion::operator<):
      (WTF::executeInsertions):
      * wtf/ListDump.h: Added.
      (WTF):
      (ListDump):
      (WTF::ListDump::ListDump):
      (WTF::ListDump::dump):
      (MapDump):
      (WTF::MapDump::MapDump):
      (WTF::MapDump::dump):
      (WTF::listDump):
      (WTF::sortedListDump):
      (WTF::lessThan):
      (WTF::mapDump):
      (WTF::sortedMapDump):
      * wtf/PrintStream.h:
      (PrintStream):
      (WTF::PrintStream::print):
      
      Conflicts:
      	Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
      
      git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153274 268f45cc-cd09-0410-ab3c-d52691b4dbfc
      827d2cf7