https://bugs.webkit.org/show_bug.cgi?id=113010

Reviewed by Goeffrey Garen.
        
1) If a CodeBlock gets jettisoned by GC, we should count the exit sites.

2) If a CodeBlock clears a structure stub during GC, it should record this, and
the DFG should prefer to not inline that access (i.e. treat it as if it had an
exit site).

3) If a PutById was seen by the baseline JIT, and the JIT attempted to cache it,
but it chose not to, then assume that it will take slow path.

4) If we frequently exited because of a structure check on a weak constant,
don't try to inline that access in the future.

5) Treat all exits that were counted as being frequent.
        
81% speed-up on Octane/gbemu. Small speed-ups elsewhere, and no regressions.

* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::finalizeUnconditionally):
(JSC):
(JSC::CodeBlock::resetStubDuringGCInternal):
(JSC::CodeBlock::reoptimize):
(JSC::CodeBlock::jettison):
(JSC::ProgramCodeBlock::jettisonImpl):
(JSC::EvalCodeBlock::jettisonImpl):
(JSC::FunctionCodeBlock::jettisonImpl):
(JSC::CodeBlock::tallyFrequentExitSites):
* bytecode/CodeBlock.h:
(CodeBlock):
(JSC::CodeBlock::tallyFrequentExitSites):
(ProgramCodeBlock):
(EvalCodeBlock):
(FunctionCodeBlock):
* bytecode/GetByIdStatus.cpp:
(JSC::GetByIdStatus::computeFor):
* bytecode/PutByIdStatus.cpp:
(JSC::PutByIdStatus::computeFor):
* bytecode/StructureStubInfo.h:
(JSC::StructureStubInfo::StructureStubInfo):
(StructureStubInfo):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::handleGetById):
(JSC::DFG::ByteCodeParser::parseBlock):
* dfg/DFGOSRExit.cpp:
(JSC::DFG::OSRExit::considerAddingAsFrequentExitSiteSlow):
* dfg/DFGOSRExit.h:
(JSC::DFG::OSRExit::considerAddingAsFrequentExitSite):
(OSRExit):
* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* runtime/Options.h:
(JSC):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146669 268f45cc-cd09-0410-ab3c-d52691b4dbfc