https://bugs.webkit.org/show_bug.cgi?id=80055
<rdar://problem/10922260>

Source/JavaScriptCore: 

Reviewed by Oliver Hunt.
        
Added tracking of the amount of executable memory typically used for a bytecode
instruction. Modified the execution counter scheme to use this, and the amount
of free memory, to determine how long to wait before invoking the JIT.
        
The result is that even if we bomb the VM with more code than can fit in our
executable memory pool, we still keep running and almost never run out of
executable memory - which ensures that if we have to JIT something critical, then
we'll likely have enough memory to do so. This also does not regress performance
on the three main benchmarks.
        
* CMakeLists.txt:
* GNUmakefile.list.am:
* JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
* JavaScriptCore.xcodeproj/project.pbxproj:
* Target.pri:
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::predictedMachineCodeSize):
(JSC):
(JSC::CodeBlock::usesOpcode):
* bytecode/CodeBlock.h:
(CodeBlock):
(JSC::CodeBlock::checkIfJITThresholdReached):
(JSC::CodeBlock::dontJITAnytimeSoon):
(JSC::CodeBlock::jitAfterWarmUp):
(JSC::CodeBlock::jitSoon):
(JSC::CodeBlock::llintExecuteCounter):
(JSC::CodeBlock::counterValueForOptimizeAfterWarmUp):
(JSC::CodeBlock::counterValueForOptimizeAfterLongWarmUp):
(JSC::CodeBlock::addressOfJITExecuteCounter):
(JSC::CodeBlock::offsetOfJITExecuteCounter):
(JSC::CodeBlock::offsetOfJITExecutionActiveThreshold):
(JSC::CodeBlock::offsetOfJITExecutionTotalCount):
(JSC::CodeBlock::jitExecuteCounter):
(JSC::CodeBlock::checkIfOptimizationThresholdReached):
(JSC::CodeBlock::optimizeNextInvocation):
(JSC::CodeBlock::dontOptimizeAnytimeSoon):
(JSC::CodeBlock::optimizeAfterWarmUp):
(JSC::CodeBlock::optimizeAfterLongWarmUp):
(JSC::CodeBlock::optimizeSoon):
* bytecode/ExecutionCounter.cpp: Added.
(JSC):
(JSC::ExecutionCounter::ExecutionCounter):
(JSC::ExecutionCounter::checkIfThresholdCrossedAndSet):
(JSC::ExecutionCounter::setNewThreshold):
(JSC::ExecutionCounter::deferIndefinitely):
(JSC::ExecutionCounter::applyMemoryUsageHeuristics):
(JSC::ExecutionCounter::applyMemoryUsageHeuristicsAndConvertToInt):
(JSC::ExecutionCounter::hasCrossedThreshold):
(JSC::ExecutionCounter::setThreshold):
(JSC::ExecutionCounter::reset):
* bytecode/ExecutionCounter.h: Added.
(JSC):
(ExecutionCounter):
(JSC::ExecutionCounter::formattedTotalCount):
* dfg/DFGOSRExitCompiler32_64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGOSRExitCompiler64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* jit/ExecutableAllocator.cpp:
(JSC::DemandExecutableAllocator::allocateNewSpace):
(JSC::ExecutableAllocator::underMemoryPressure):
(JSC):
(JSC::ExecutableAllocator::memoryPressureMultiplier):
* jit/ExecutableAllocator.h:
* jit/ExecutableAllocatorFixedVMPool.cpp:
(JSC::ExecutableAllocator::memoryPressureMultiplier):
(JSC):
* jit/JIT.cpp:
(JSC::JIT::privateCompile):
* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::jitCompileAndSetHeuristics):
* llint/LowLevelInterpreter32_64.asm:
* runtime/JSGlobalData.h:
(JSGlobalData):
* runtime/Options.cpp:
(Options):
(JSC::Options::initializeOptions):
* runtime/Options.h:
(Options):
* wtf/SimpleStats.h: Added.
(WTF):
(SimpleStats):
(WTF::SimpleStats::SimpleStats):
(WTF::SimpleStats::add):
(WTF::SimpleStats::operator!):
(WTF::SimpleStats::count):
(WTF::SimpleStats::sum):
(WTF::SimpleStats::sumOfSquares):
(WTF::SimpleStats::mean):
(WTF::SimpleStats::variance):
(WTF::SimpleStats::standardDeviation):

Source/WebCore: 

Reviewed by Oliver Hunt.

No new tests, since there's no new functionality.

* ForwardingHeaders/wtf/SimpleStats.h: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@109705 268f45cc-cd09-0410-ab3c-d52691b4dbfc