fourthTier: CFA should defend against results seeming inconsistent due to a watchpoin...
authoroliver@apple.com <oliver@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Thu, 25 Jul 2013 03:59:00 +0000 (03:59 +0000)
committeroliver@apple.com <oliver@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Thu, 25 Jul 2013 03:59:00 +0000 (03:59 +0000)
commit67e0f33a6eb45372a970c178c51647134ab87e88
tree5745665ff663d6ba21115cd3744d2fc6ca5f5ea5
parentfe0cc19e72c220e82db82c11ae0236083cea5038
fourthTier: CFA should defend against results seeming inconsistent due to a watchpoint firing during compilation
https://bugs.webkit.org/show_bug.cgi?id=115083

Reviewed by Geoffrey Garen.

This ruggedizes our racyness with respect to watchpoints. We want to be able to assert,
in some places, that a watchpoint-based optimization has only occurred if the
watchpoint set was still valid. But currently we *can* soundly do watchpoint-based
optimizations even for invalid watchpoints, so long as we recorded in the IR that we
had done so; this will then lead to the code being insta-jettisoned after compilation
completes. Obviously, we don't want this to happen often - but we do want to allow it
precisely in the case of watchpoint races.

This adds the ability to assert that we hadn't over-watchpointed ourselves, with and
exemption for races.

* dfg/DFGAbstractState.cpp:
(JSC::DFG::AbstractState::executeEffects):
* dfg/DFGAbstractValue.cpp:
(JSC::DFG::AbstractValue::setFuturePossibleStructure):
(JSC::DFG::AbstractValue::filterFuturePossibleStructure):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::addStructureTransitionCheck):
(JSC::DFG::ByteCodeParser::parseResolveOperations):
(JSC::DFG::ByteCodeParser::parseBlock):
* dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::addStructureTransitionCheck):
* dfg/DFGDesiredWatchpoints.h:
(GenericDesiredWatchpoints):
(JSC::DFG::GenericDesiredWatchpoints::isStillValid):
(JSC::DFG::GenericDesiredWatchpoints::shouldAssumeMixedState):
(JSC::DFG::GenericDesiredWatchpoints::isValidOrMixed):
(JSC::DFG::DesiredWatchpoints::isStillValid):
(JSC::DFG::DesiredWatchpoints::shouldAssumeMixedState):
(JSC::DFG::DesiredWatchpoints::isValidOrMixed):
(DesiredWatchpoints):
* dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::canOptimizeStringObjectAccess):
* dfg/DFGGraph.h:
(JSC::DFG::Graph::masqueradesAsUndefinedWatchpointIsStillValid):
(Graph):
* dfg/DFGJITCompiler.cpp:
(JSC::DFG::JITCompiler::link):
(JSC::DFG::JITCompiler::compile):
(JSC::DFG::JITCompiler::compileFunction):
* dfg/DFGJITCompiler.h:
(JSC::DFG::JITCompiler::addLazily):
(JITCompiler):
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::compilePeepHoleObjectEquality):
* dfg/DFGSpeculativeJIT.h:
(SpeculativeJIT):
(JSC::DFG::SpeculativeJIT::masqueradesAsUndefinedWatchpointIsStillValid):
(JSC::DFG::SpeculativeJIT::speculationWatchpointForMasqueradesAsUndefined):
(JSC::DFG::SpeculativeJIT::speculateStringObjectForStructure):
* dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::nonSpeculativeNonPeepholeCompareNull):
(JSC::DFG::SpeculativeJIT::nonSpeculativePeepholeBranchNull):
(JSC::DFG::SpeculativeJIT::compileObjectEquality):
(JSC::DFG::SpeculativeJIT::compileObjectToObjectOrOtherEquality):
(JSC::DFG::SpeculativeJIT::compilePeepHoleObjectToObjectOrOtherEquality):
(JSC::DFG::SpeculativeJIT::compileObjectOrOtherLogicalNot):
(JSC::DFG::SpeculativeJIT::emitObjectOrOtherBranch):
(JSC::DFG::SpeculativeJIT::compile):
* dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::nonSpeculativeNonPeepholeCompareNull):
(JSC::DFG::SpeculativeJIT::nonSpeculativePeepholeBranchNull):
(JSC::DFG::SpeculativeJIT::compileObjectEquality):
(JSC::DFG::SpeculativeJIT::compileObjectToObjectOrOtherEquality):
(JSC::DFG::SpeculativeJIT::compilePeepHoleObjectToObjectOrOtherEquality):
(JSC::DFG::SpeculativeJIT::compileObjectOrOtherLogicalNot):
(JSC::DFG::SpeculativeJIT::emitObjectOrOtherBranch):
(JSC::DFG::SpeculativeJIT::compile):
* ftl/FTLCompile.cpp:
(JSC::FTL::compile):
* ftl/FTLState.h:
(State):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153130 268f45cc-cd09-0410-ab3c-d52691b4dbfc
16 files changed:
Source/JavaScriptCore/ChangeLog
Source/JavaScriptCore/dfg/DFGAbstractState.cpp
Source/JavaScriptCore/dfg/DFGAbstractValue.cpp
Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp
Source/JavaScriptCore/dfg/DFGDesiredWatchpoints.h
Source/JavaScriptCore/dfg/DFGFixupPhase.cpp
Source/JavaScriptCore/dfg/DFGGraph.h
Source/JavaScriptCore/dfg/DFGJITCompiler.cpp
Source/JavaScriptCore/dfg/DFGJITCompiler.h
Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp
Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h
Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp
Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp
Source/JavaScriptCore/ftl/FTLCompile.cpp
Source/JavaScriptCore/ftl/FTLState.h