https://bugs.webkit.org/show_bug.cgi?id=71202

Reviewed by Oliver Hunt.
        
Value profiles now have an extra special slot not used by the old JIT's
profiling, which is reserved for OSR exits.
        
The DFG's OSR exit code now knows which register, node index, and value
profiling site was responsible for the (possibly flawed) information that
led to the OSR failure. This is somewhat opportunistic and imperfect;
if there's a lot of control flow between the value profiling site and the
OSR failure point, then this mechanism simply gives up. It also gives up
if the OSR failure is caused by either known deficiencies in the DFG
(like that we always assume that the index in a strict charCodeAt access
is within bounds) or where the OSR failure would be catalogues and
profiled through other means (like slow case counters).
        
This patch also adds the notion of a JSValueRegs, which is either a
single register in JSVALUE64 or a pair in JSVALUE32_64. We should
probably move the 32_64 DFG towards using this, since it often makes it
easier to share code between 64 and 32_64.
        
Also fixed a number of pathologies that this uncovered. op_method_check 
didn't have a value profiling site on the slow path. GetById should not
always force OSR exit if it never executed in the old JIT; we may be
able to infer its type if it's a array or string length get. Finally,
these changes benefit from a slight tweak to optimization delay
heuristics (profile fullness is now 0.35 instead of 0.25).
        
3.8% speed-up on Kraken, mostly due to ~35% on both stanford-crypto-aes
and imaging-darkroom.

* bytecode/ValueProfile.cpp:
(JSC::ValueProfile::computeStatistics):
(JSC::ValueProfile::computeUpdatedPrediction):
* bytecode/ValueProfile.h:
(JSC::ValueProfile::ValueProfile):
(JSC::ValueProfile::specFailBucket):
(JSC::ValueProfile::numberOfSamples):
(JSC::ValueProfile::isLive):
(JSC::ValueProfile::numberOfInt32s):
(JSC::ValueProfile::numberOfDoubles):
(JSC::ValueProfile::numberOfCells):
(JSC::ValueProfile::numberOfObjects):
(JSC::ValueProfile::numberOfFinalObjects):
(JSC::ValueProfile::numberOfStrings):
(JSC::ValueProfile::numberOfArrays):
(JSC::ValueProfile::numberOfBooleans):
(JSC::ValueProfile::dump):
* dfg/DFGAbstractState.cpp:
(JSC::DFG::AbstractState::execute):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::getPredictionWithoutOSRExit):
(JSC::DFG::ByteCodeParser::getPrediction):
(JSC::DFG::ByteCodeParser::parseBlock):
* dfg/DFGGPRInfo.h:
(JSC::DFG::JSValueRegs::JSValueRegs):
(JSC::DFG::JSValueRegs::operator!):
(JSC::DFG::JSValueRegs::gpr):
(JSC::DFG::JSValueSource::JSValueSource):
(JSC::DFG::JSValueSource::unboxedCell):
(JSC::DFG::JSValueSource::operator!):
(JSC::DFG::JSValueSource::isAddress):
(JSC::DFG::JSValueSource::offset):
(JSC::DFG::JSValueSource::base):
(JSC::DFG::JSValueSource::gpr):
(JSC::DFG::JSValueSource::asAddress):
(JSC::DFG::JSValueSource::notAddress):
(JSC::DFG::JSValueRegs::tagGPR):
(JSC::DFG::JSValueRegs::payloadGPR):
(JSC::DFG::JSValueSource::tagGPR):
(JSC::DFG::JSValueSource::payloadGPR):
(JSC::DFG::JSValueSource::hasKnownTag):
(JSC::DFG::JSValueSource::tag):
* dfg/DFGGenerationInfo.h:
(JSC::DFG::GenerationInfo::jsValueRegs):
* dfg/DFGGraph.h:
(JSC::DFG::Graph::valueProfileFor):
* dfg/DFGJITCodeGenerator.h:
(JSC::JSValueOperand::jsValueRegs):
* dfg/DFGJITCompiler.cpp:
(JSC::DFG::JITCompiler::exitSpeculativeWithOSR):
* dfg/DFGJITCompiler.h:
(JSC::DFG::JITCompiler::valueProfileFor):
* dfg/DFGJITCompiler32_64.cpp:
(JSC::DFG::JITCompiler::exitSpeculativeWithOSR):
* dfg/DFGPropagator.cpp:
(JSC::DFG::Propagator::propagateNodePredictions):
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::OSRExit::OSRExit):
(JSC::DFG::SpeculativeJIT::compilePeepHoleObjectEquality):
(JSC::DFG::SpeculativeJIT::checkArgumentTypes):
(JSC::DFG::SpeculativeJIT::compileGetCharCodeAt):
(JSC::DFG::SpeculativeJIT::compileGetByValOnString):
(JSC::DFG::SpeculativeJIT::compilePutByValForByteArray):
(JSC::DFG::SpeculativeJIT::compileGetByValOnByteArray):
* dfg/DFGSpeculativeJIT.h:
(JSC::DFG::SpeculativeJIT::speculationCheck):
(JSC::DFG::SpeculativeJIT::terminateSpeculativeExecution):
* dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::fillSpeculateIntInternal):
(JSC::DFG::SpeculativeJIT::fillSpeculateDouble):
(JSC::DFG::SpeculativeJIT::fillSpeculateCell):
(JSC::DFG::SpeculativeJIT::fillSpeculateBoolean):
(JSC::DFG::SpeculativeJIT::compileObjectEquality):
(JSC::DFG::SpeculativeJIT::compileObjectOrOtherLogicalNot):
(JSC::DFG::SpeculativeJIT::compileLogicalNot):
(JSC::DFG::SpeculativeJIT::emitObjectOrOtherBranch):
(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::compileObjectEquality):
(JSC::DFG::SpeculativeJIT::compileObjectOrOtherLogicalNot):
(JSC::DFG::SpeculativeJIT::compileLogicalNot):
(JSC::DFG::SpeculativeJIT::emitObjectOrOtherBranch):
(JSC::DFG::SpeculativeJIT::emitBranch):
(JSC::DFG::SpeculativeJIT::compile):
* jit/JITPropertyAccess.cpp:
(JSC::JIT::emitSlow_op_method_check):
* jit/JITPropertyAccess32_64.cpp:
(JSC::JIT::emitSlow_op_method_check):
* runtime/Heuristics.cpp:
(JSC::Heuristics::initializeHeuristics):
* runtime/JSValue.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@98912 268f45cc-cd09-0410-ab3c-d52691b4dbfc