https://bugs.webkit.org/show_bug.cgi?id=117272

Reviewed by Oliver Hunt.

This makes the DFG CFA immediately detect when it hit a contradiction. Previously
we might not know this: for example if we did an int32 type check on a known string;
the code would definitely always exit but the CFA would think that we wouldn't have
even though it would have computed a BOTTOM (i.e. contradictory) value for that
variable.

This requires two other changes:

- CFA must report contradictions as if they are frequent exit sites, since
  contradictory speculations will subsequently get replaced with ForceOSRExit.
  ForceOSRExit cannot itself report profiling data back to the DFG::ExitProfile. So,
  we do this on behalf of the speculation, eagerly, within the CFA. This also has
  the effect of speeding convergence somewhat. We may want to revisit this later;
  for example we might want to instead have the notion of a ForceOSRExit that knows
  the set of speculations that got folded into it.

- This revealed a bug where the CFA was modeling CheckStructure on a node that had
  a known singleton m_futurePossibleStructure set somewhat differently than the
  constant folder. If the CheckStructure was checking a structure set with two or
  more structures in it, it would not filter the abstract value. But the constant
  folder would turn this into a watchpoint on the singleton structure, thereby
  filtering the value. This discrepancy meant that we wouldn't realize the
  contradiction until the backend, and the AbstractState::bail() method asserts that
  we always realize contradictions in the constant folder.

* JavaScriptCore.xcodeproj/project.pbxproj:
* bytecode/CodeBlock.h:
(JSC::CodeBlock::addFrequentExitSite):
(JSC::CodeBlock::hasExitSite):
(CodeBlock):
* bytecode/DFGExitProfile.cpp:
(JSC::DFG::ExitProfile::add):
(JSC::DFG::ExitProfile::hasExitSite):
(JSC::DFG::QueryableExitProfile::QueryableExitProfile):
(JSC::DFG::QueryableExitProfile::~QueryableExitProfile):
(DFG):
(JSC::DFG::QueryableExitProfile::initialize):
* bytecode/DFGExitProfile.h:
(JSC::DFG::FrequentExitSite::FrequentExitSite):
(ExitProfile):
(JSC::DFG::ExitProfile::hasExitSite):
(QueryableExitProfile):
* bytecode/ExitKind.cpp:
(JSC::exitKindToString):
* dfg/DFGAbstractState.cpp:
(JSC::DFG::AbstractState::AbstractState):
(JSC::DFG::AbstractState::beginBasicBlock):
(JSC::DFG::AbstractState::reset):
(JSC::DFG::AbstractState::startExecuting):
(JSC::DFG::AbstractState::executeEffects):
(JSC::DFG::AbstractState::execute):
(JSC::DFG::AbstractState::filter):
(DFG):
(JSC::DFG::AbstractState::filterArrayModes):
(JSC::DFG::AbstractState::filterByValue):
(JSC::DFG::AbstractState::bail):
* dfg/DFGAbstractState.h:
(AbstractState):
(JSC::DFG::AbstractState::filter):
(JSC::DFG::AbstractState::filterArrayModes):
(JSC::DFG::AbstractState::filterByValue):
(JSC::DFG::AbstractState::filterByType):
* dfg/DFGAbstractValue.cpp:
(JSC::DFG::AbstractValue::filter):
(JSC::DFG::AbstractValue::filterArrayModes):
(DFG):
(JSC::DFG::AbstractValue::filterByValue):
(JSC::DFG::AbstractValue::normalizeClarity):
* dfg/DFGAbstractValue.h:
(AbstractValue):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::InlineStackEntry::InlineStackEntry):
* dfg/DFGCFAPhase.cpp:
(JSC::DFG::CFAPhase::performBlockCFA):
* dfg/DFGCapabilities.cpp:
(JSC::DFG::debugFail):
(JSC::DFG::capabilityLevel):
* dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::foldConstants):
(ConstantFoldingPhase):
(JSC::DFG::ConstantFoldingPhase::paintUnreachableCode):
* dfg/DFGFiltrationResult.h: Added.
(DFG):
* dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
* dfg/DFGNodeType.h:
(DFG):
* dfg/DFGOSRExitBase.cpp:
(JSC::DFG::OSRExitBase::considerAddingAsFrequentExitSiteSlow):
* dfg/DFGOSRExitBase.h:
(JSC::DFG::OSRExitBase::considerAddingAsFrequentExitSite):
* dfg/DFGPredictionPropagationPhase.cpp:
(JSC::DFG::PredictionPropagationPhase::propagate):
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::backwardTypeCheck):
(JSC::DFG::SpeculativeJIT::bail):
(DFG):
(JSC::DFG::SpeculativeJIT::compile):
(JSC::DFG::SpeculativeJIT::compileToStringOnCell):
(JSC::DFG::SpeculativeJIT::speculateStringObject):
(JSC::DFG::SpeculativeJIT::speculateStringOrStringObject):
* dfg/DFGSpeculativeJIT.h:
(SpeculativeJIT):
* dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::fillSpeculateIntInternal):
(JSC::DFG::SpeculativeJIT::fillSpeculateDouble):
(JSC::DFG::SpeculativeJIT::fillSpeculateCell):
(JSC::DFG::SpeculativeJIT::fillSpeculateBoolean):
(JSC::DFG::SpeculativeJIT::compile):
* dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::fillSpeculateIntInternal):
(JSC::DFG::SpeculativeJIT::fillSpeculateDouble):
(JSC::DFG::SpeculativeJIT::fillSpeculateCell):
(JSC::DFG::SpeculativeJIT::fillSpeculateBoolean):
(JSC::DFG::SpeculativeJIT::compile):
* ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile):
* ftl/FTLLowerDFGToLLVM.cpp:
(JSC::FTL::LowerDFGToLLVM::compileNode):
(JSC::FTL::LowerDFGToLLVM::appendTypeCheck):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153213 268f45cc-cd09-0410-ab3c-d52691b4dbfc