[iOS] Captions are clipped in documents using pagination
https://bugs.webkit.org/show_bug.cgi?id=119072

Reviewed by Beth Dakin.

MediaControlTextTrackContainerElement::createTextTrackRepresentationImage() is called
to paint captions into a layer used for fullscreen video. It did the painting using
a subtree paint, but starting at the root RenderView's layer. This is problematic,
because the caption painting is subject to clipping for columns, and any enclosing
overflow:hidden container.

Fix this by starting the paint at the MediaControlTextTrackContainerElement's
renderer's layer. By doing this we don't have to worry about an offset, so no
translation is required.

Also make sure we update layer before grabbing the renderer (in case layout
destroys it).

* html/shadow/MediaControlElements.cpp:
(WebCore::MediaControlTextTrackContainerElement::createTextTrackRepresentationImage):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153112 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: JITCode should abstract exactly how the JIT code is structured and where it was allocated
https://bugs.webkit.org/show_bug.cgi?id=113437

Reviewed by Mark Hahnenberg.

JITCode is now a virtual base class, which will allow different JITs to have radically
different memory allocation and management conventions in the future. It will also
make it easier to store JIT-specific meta-data in CodeBlock just by putting it into
an appropriate JITCode subclass.

For now there is one subclass, DirectJITCode, which just behaves like JITCode used to
behave.

* assembler/RepatchBuffer.h:
(JSC::RepatchBuffer::RepatchBuffer):
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::resetStubInternal):
(JSC::CodeBlock::bytecodeOffset):
(JSC::CodeBlock::codeOriginForReturn):
* bytecode/CodeBlock.h:
(JSC::CodeBlock::setJITCode):
(JSC::CodeBlock::getJITCode):
(JSC::CodeBlock::getJITType):
(CodeBlock):
* dfg/DFGDriver.cpp:
(JSC::DFG::compile):
(JSC::DFG::tryCompile):
(JSC::DFG::tryCompileFunction):
* dfg/DFGDriver.h:
(DFG):
(JSC::DFG::tryCompile):
(JSC::DFG::tryCompileFunction):
* dfg/DFGJITCompiler.cpp:
(JSC::DFG::JITCompiler::compile):
(JSC::DFG::JITCompiler::compileFunction):
* dfg/DFGJITCompiler.h:
(JITCompiler):
* dfg/DFGOSREntry.cpp:
(JSC::DFG::prepareOSREntry):
* dfg/DFGOSRExit.cpp:
(JSC::DFG::OSRExit::codeLocationForRepatch):
* dfg/DFGOSRExitCompiler32_64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGOSRExitCompiler64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGOperations.cpp:
* interpreter/Interpreter.cpp:
(JSC::Interpreter::execute):
(JSC::Interpreter::executeCall):
(JSC::Interpreter::executeConstruct):
* jit/JIT.cpp:
(JSC::JIT::privateCompile):
* jit/JIT.h:
(JSC::JIT::compile):
(JIT):
* jit/JITCode.cpp:
(JSC):
(JSC::JITCode::JITCode):
(JSC::JITCode::~JITCode):
(JSC::JITCode::execute):
(JSC::JITCode::hostFunction):
(JSC::DirectJITCode::DirectJITCode):
(JSC::DirectJITCode::~DirectJITCode):
(JSC::DirectJITCode::addressForCall):
(JSC::DirectJITCode::executableAddressAtOffset):
(JSC::DirectJITCode::dataAddressAtOffset):
(JSC::DirectJITCode::offsetOf):
(JSC::DirectJITCode::size):
(JSC::DirectJITCode::contains):
* jit/JITCode.h:
(JSC):
(JITCode):
(JSC::JITCode::bottomTierJIT):
(JSC::JITCode::topTierJIT):
(JSC::JITCode::nextTierJIT):
(JSC::JITCode::isOptimizingJIT):
(JSC::JITCode::isBaselineCode):
(JSC::JITCode::jitType):
(JSC::JITCode::jitTypeFor):
(JSC::JITCode::executableAddress):
(JSC::JITCode::start):
(JSC::JITCode::end):
(DirectJITCode):
* jit/JITDriver.h:
(JSC::jitCompileIfAppropriate):
(JSC::jitCompileFunctionIfAppropriate):
* jit/JITStubs.cpp:
(JSC::lazyLinkFor):
(JSC::DEFINE_STUB_FUNCTION):
* jit/ThunkGenerators.cpp:
(JSC::virtualForGenerator):
* llint/LLIntEntrypoints.cpp:
(JSC::LLInt::getFunctionEntrypoint):
(JSC::LLInt::getEvalEntrypoint):
(JSC::LLInt::getProgramEntrypoint):
* llint/LLIntEntrypoints.h:
(JSC):
(LLInt):
(JSC::LLInt::getEntrypoint):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::jitCompileAndSetHeuristics):
(JSC::LLInt::entryOSR):
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* runtime/Executable.cpp:
(JSC::EvalExecutable::compileInternal):
(JSC::ProgramExecutable::compileInternal):
(JSC::FunctionExecutable::compileForCallInternal):
(JSC::FunctionExecutable::compileForConstructInternal):
* runtime/Executable.h:
(JSC::ExecutableBase::generatedJITCodeForCall):
(JSC::ExecutableBase::generatedJITCodeForConstruct):
(JSC::ExecutableBase::generatedJITCodeFor):
(ExecutableBase):
(JSC::ExecutableBase::hostCodeEntryFor):
(JSC::ExecutableBase::jsCodeEntryFor):
(JSC::ExecutableBase::jsCodeWithArityCheckEntryFor):
(JSC::NativeExecutable::create):
(JSC::NativeExecutable::finishCreation):
(JSC::EvalExecutable::generatedJITCode):
(JSC::ProgramExecutable::generatedJITCode):
* runtime/ExecutionHarness.h:
(JSC::prepareForExecution):
(JSC::prepareFunctionForExecution):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153113 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: DFG should abstract out how it does forward exits, and that code should be simplified
https://bugs.webkit.org/show_bug.cgi?id=113894

Reviewed by Mark Hahnenberg.

1) We previously had two different ways of convertingToForward, one path for
   where we had a ValueRecovery for the current node and one where we didn't.
   But the paths were doing exactly the same thing except that if you have a
   ValueRecovery, you also find the last applicable mov hint and do some
   extra things. This patch combines the two paths and bases both of them on
   the previous no-ValueRecovery path, which was simpler to begin with.

2) This moves the logic into DFG::OSRExit, which further simplifies the code
   and makes the logic available to the FTL.

* dfg/DFGOSRExit.cpp:
(JSC::DFG::OSRExit::convertToForward):
(DFG):
* dfg/DFGOSRExit.h:
(DFG):
(OSRExit):
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::convertLastOSRExitToForward):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153114 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: Everyone should know about the FTL
https://bugs.webkit.org/show_bug.cgi?id=113897

Reviewed by Mark Hahnenberg.

In order to get OSR exit to work right, we need the distinction between DFG and
FTL to be clear even after compilation finishes, since they will have subtly
different OSR stories and likely use different data structures.

* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::resetStubInternal):
(JSC::ProgramCodeBlock::compileOptimized):
(JSC::EvalCodeBlock::compileOptimized):
(JSC::FunctionCodeBlock::compileOptimized):
(JSC::CodeBlock::adjustedExitCountThreshold):
(JSC::CodeBlock::tallyFrequentExitSites):
* bytecode/CodeBlock.h:
(JSC::CodeBlock::setJITCode):
(JSC::CodeBlock::hasOptimizedReplacement):
(JSC::ExecState::isInlineCallFrame):
* ftl/FTLCompile.cpp:
(JSC::FTL::compile):
* ftl/FTLJITCode.cpp:
(JSC::FTL::JITCode::JITCode):
* ftl/FTLState.cpp:
(JSC::FTL::State::dumpState):
* heap/DFGCodeBlocks.cpp:
(JSC::DFGCodeBlocks::jettison):
* interpreter/Interpreter.cpp:
(JSC::getLineNumberForCallFrame):
(JSC::getCallerInfo):
* jit/JITCode.cpp:
(WTF::printInternal):
* jit/JITCode.h:
(JSC::JITCode::topTierJIT):
(JSC::JITCode::nextTierJIT):
(JITCode):
(JSC::JITCode::isJIT):
(JSC::JITCode::isLowerTier):
(JSC::JITCode::isHigherTier):
(JSC::JITCode::isLowerOrSameTier):
(JSC::JITCode::isHigherOrSameTier):
(JSC::JITCode::isOptimizingJIT):
* jit/JITDriver.h:
(JSC::jitCompileIfAppropriate):
(JSC::jitCompileFunctionIfAppropriate):
* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* runtime/Executable.cpp:
(JSC::EvalExecutable::compileOptimized):
(JSC::samplingDescription):
(JSC::ProgramExecutable::compileOptimized):
(JSC::FunctionExecutable::compileOptimizedForCall):
(JSC::FunctionExecutable::compileOptimizedForConstruct):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153115 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: put DFG data into a DFG::JITCode, and put common DFG and FTL data into something accessible from both DFG::JITCode and FTL::JITCode
https://bugs.webkit.org/show_bug.cgi?id=113905

Reviewed by Geoffrey Garen.

This removes one pointer from CodeBlock.

It also gives us a framework for having JITType-specific data in CodeBlock, by
putting it into the appropriate JITCode class (either DFG::JITCode or
FTL::JITCode). And it allows us to have DFG and FTL share some common data,
via DFG::CommonData, which is stored in both DFG::JITCode and FTL::JITCode and
always accessible via JITCode::dfgCommon().

* CMakeLists.txt:
* GNUmakefile.list.am:
* JavaScriptCore.xcodeproj/project.pbxproj:
* Target.pri:
* bytecode/CodeBlock.cpp:
(JSC):
(JSC::CodeBlock::dumpBytecode):
(JSC::CodeBlock::visitAggregate):
(JSC::CodeBlock::performTracingFixpointIteration):
(JSC::CodeBlock::finalizeUnconditionally):
(JSC::CodeBlock::stronglyVisitWeakReferences):
(JSC::CodeBlock::shrinkToFit):
(JSC::CodeBlock::tallyFrequentExitSites):
* bytecode/CodeBlock.h:
(CodeBlock):
(JSC::CodeBlock::setJITCode):
(JSC::CodeBlock::shouldImmediatelyAssumeLivenessDuringScan):
(JSC::DFGCodeBlocks::mark):
* dfg/DFGAssemblyHelpers.h:
* dfg/DFGCommonData.cpp: Added.
(DFG):
(JSC::DFG::CommonData::notifyCompilingStructureTransition):
(JSC::DFG::CommonData::shrinkToFit):
* dfg/DFGCommonData.h: Added.
(JSC):
(DFG):
(JSC::DFG::WeakReferenceTransition::WeakReferenceTransition):
(WeakReferenceTransition):
(CommonData):
(JSC::DFG::CommonData::CommonData):
* dfg/DFGDriver.cpp:
(JSC::DFG::compile):
(JSC::DFG::tryCompile):
(JSC::DFG::tryCompileFunction):
* dfg/DFGDriver.h:
(DFG):
(JSC::DFG::tryCompile):
(JSC::DFG::tryCompileFunction):
* dfg/DFGGraph.h:
(Graph):
* dfg/DFGJITCode.cpp: Added.
(DFG):
(JSC::DFG::JITCode::JITCode):
(JSC::DFG::JITCode::~JITCode):
(JSC::DFG::JITCode::dfgCommon):
(JSC::DFG::JITCode::dfg):
(JSC::DFG::JITCode::shrinkToFit):
* dfg/DFGJITCode.h: Added.
(DFG):
(JITCode):
(JSC::DFG::JITCode::appendOSREntryData):
(JSC::DFG::JITCode::osrEntryDataForBytecodeIndex):
(JSC::DFG::JITCode::appendOSRExit):
(JSC::DFG::JITCode::lastOSRExit):
(JSC::DFG::JITCode::appendSpeculationRecovery):
(JSC::DFG::JITCode::appendWatchpoint):
* dfg/DFGJITCompiler.cpp:
(JSC::DFG::JITCompiler::JITCompiler):
(JSC::DFG::JITCompiler::linkOSRExits):
(JSC::DFG::JITCompiler::link):
(JSC::DFG::JITCompiler::compile):
(JSC::DFG::JITCompiler::compileFunction):
* dfg/DFGJITCompiler.h:
(JITCompiler):
(JSC::DFG::JITCompiler::addWeakReference):
(JSC::DFG::JITCompiler::noticeOSREntry):
(JSC::DFG::JITCompiler::jitCode):
* dfg/DFGOSREntry.cpp:
(JSC::DFG::prepareOSREntry):
* dfg/DFGOSRExit.h:
(OSRExit):
* dfg/DFGOSRExitCompiler.cpp:
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::SpeculativeJIT):
(JSC::DFG::SpeculativeJIT::backwardSpeculationCheck):
(JSC::DFG::SpeculativeJIT::speculationWatchpoint):
(JSC::DFG::SpeculativeJIT::convertLastOSRExitToForward):
* dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* dfg/DFGVariableEventStream.cpp:
* ftl/FTLCompile.cpp:
(JSC::FTL::compile):
* ftl/FTLJITCode.cpp:
(JSC::FTL::JITCode::JITCode):
(JSC::FTL::JITCode::~JITCode):
(FTL):
(JSC::FTL::JITCode::initializeCode):
(JSC::FTL::JITCode::addressForCall):
(JSC::FTL::JITCode::executableAddressAtOffset):
(JSC::FTL::JITCode::dataAddressAtOffset):
(JSC::FTL::JITCode::offsetOf):
(JSC::FTL::JITCode::size):
(JSC::FTL::JITCode::contains):
(JSC::FTL::JITCode::ftl):
(JSC::FTL::JITCode::dfgCommon):
* ftl/FTLJITCode.h:
(JITCode):
* ftl/FTLLowerDFGToLLVM.cpp:
(JSC::FTL::LowerDFGToLLVM::compileStructureTransitionWatchpoint):
(JSC::FTL::LowerDFGToLLVM::compilePutStructure):
(JSC::FTL::LowerDFGToLLVM::compilePhantomPutStructure):
(JSC::FTL::LowerDFGToLLVM::addWeakReference):
(LowerDFGToLLVM):
(JSC::FTL::LowerDFGToLLVM::weakPointer):
* ftl/FTLState.cpp:
(FTL):
(JSC::FTL::State::State):
(JSC::FTL::State::dumpState):
* ftl/FTLState.h:
(State):
* heap/DFGCodeBlocks.cpp:
(JSC::DFGCodeBlocks::~DFGCodeBlocks):
(JSC::DFGCodeBlocks::jettison):
(JSC::DFGCodeBlocks::clearMarks):
(JSC::DFGCodeBlocks::deleteUnmarkedJettisonedCodeBlocks):
(JSC::DFGCodeBlocks::traceMarkedCodeBlocks):
* jit/JITCode.cpp:
(JSC::JITCode::dfgCommon):
(JSC):
(JSC::JITCode::dfg):
(JSC::JITCode::ftl):
(JSC::DirectJITCode::DirectJITCode):
(JSC::DirectJITCode::initializeCodeRef):
(JSC::DirectJITCode::addressForCall):
(JSC::DirectJITCode::executableAddressAtOffset):
(JSC::DirectJITCode::dataAddressAtOffset):
(JSC::DirectJITCode::offsetOf):
(JSC::DirectJITCode::size):
(JSC::DirectJITCode::contains):
* jit/JITCode.h:
(DFG):
(FTL):
(JSC):
(JITCode):
(DirectJITCode):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153116 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: DFG should better abstract arguments
https://bugs.webkit.org/show_bug.cgi?id=114073

Reviewed by Mark Hahnenberg.

* dfg/DFGGPRInfo.h:
(GPRInfo):
(JSC::DFG::GPRInfo::toArgumentRegister):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153117 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: DFG should better abstract floating point arguments
https://bugs.webkit.org/show_bug.cgi?id=114300

Reviewed by Mark Hahnenberg.

* dfg/DFGFPRInfo.h:
(FPRInfo):
(JSC::DFG::FPRInfo::toArgumentRegister):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153118 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: DFG should provide utilities for common OSR exit tasks
https://bugs.webkit.org/show_bug.cgi?id=114306

Reviewed by Mark Hahnenberg.

Just abstract out some things that the FTL will want to use as well.

* CMakeLists.txt:
* GNUmakefile.list.am:
* JavaScriptCore.xcodeproj/project.pbxproj:
* Target.pri:
* dfg/DFGDriver.cpp:
(JSC::DFG::compile):
* dfg/DFGOSRExitCompiler.cpp:
* dfg/DFGOSRExitCompiler.h:
(OSRExitCompiler):
* dfg/DFGOSRExitCompiler32_64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGOSRExitCompiler64.cpp:
(JSC::DFG::OSRExitCompiler::compileExit):
* dfg/DFGOSRExitCompilerCommon.cpp: Added.
(DFG):
(JSC::DFG::handleExitCounts):
(JSC::DFG::reifyInlinedCallFrames):
(JSC::DFG::adjustAndJumpToTarget):
* dfg/DFGOSRExitCompilerCommon.h: Added.
(DFG):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153119 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: DFG should be able to query Structure without modifying it
https://bugs.webkit.org/show_bug.cgi?id=114708

Reviewed by Oliver Hunt.

This is work towards allowing the DFG, and FTL, to run on a separate thread.
The idea is that the most evil thing that the DFG does that has thread-safety
issues is fiddling with Structures by calling Structure::get(). This can lead
to rematerialization of property tables, which is definitely not thread-safe
due to how StringImpl works. So, this patch completely side-steps the problem
by creating a new version of Structure::get, called
Structure::getWithoutMaterializing, which may choose to do an O(n) search if
necessary to avoid materialization. I believe this should be fine - the DFG
does't call into these code path often enough for this to matter, and most of
the time, the Structure that we call this on will already have a property
table because some inline cache would have already called ::get() on that
Structure.

Also cleaned up the materialization logic: we can stop the search as soon as
we find any Structure with a property table rather than searching all the way
for a pinned one.

* bytecode/GetByIdStatus.cpp:
(JSC::GetByIdStatus::computeFor):
* bytecode/PutByIdStatus.cpp:
(JSC::PutByIdStatus::computeFromLLInt):
(JSC::PutByIdStatus::computeFor):
* runtime/Structure.cpp:
(JSC::Structure::findStructuresAndMapForMaterialization):
(JSC::Structure::materializePropertyMap):
(JSC::Structure::getWithoutMaterializing):
(JSC):
* runtime/Structure.h:
(Structure):
* runtime/StructureInlines.h:
(JSC::Structure::getWithoutMaterializing):
(JSC):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153120 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: Landing the initial FTL logic in a single commit to avoid spurious
broken builds.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153121 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: all inline caches should thread-safe enough to allow a concurrent compilation thread to read them safely
https://bugs.webkit.org/show_bug.cgi?id=114762

Source/JavaScriptCore:

Reviewed by Mark Hahnenberg.

For most inline caches this is easy: the inline cache has a clean temporal
separation between doing the requested action (which may take an unbounded
amount of time, may recurse, and may do arbitrary things) and recording the
relevant information in the cache. So, we just put locks around the
recording bit. That part is always O(1) and does not recurse. The lock we
use is per-CodeBlock to achieve a good balance between locking granularity
and low space overhead. So a concurrent compilation thread will only block
if an inline cache ping-pongs in the code block being compiled (or inlined)
and never when other inline caches do things.

For resolve operations, it's a bit tricky. The global resolve bit works
like any other IC in that it has the clean temporal separation. But the
operations vector itself doesn't have this separation, since we will be
filling it in tandem with actions that may take a long time. This patch
gets around this by having a m_ready bit in the ResolveOperations and
PutToBaseOperation. This is set while holding the CodeBlock's lock. If the
DFG observes the m_ready bit not set (while holding the lock) then it
conservatively assumes that the resolve hasn't happened yet and just
plants a ForceOSRExit.

* bytecode/CallLinkStatus.cpp:
(JSC::CallLinkStatus::computeFor):
* bytecode/CodeBlock.h:
(CodeBlock):
* bytecode/GetByIdStatus.cpp:
(JSC::GetByIdStatus::computeFor):
* bytecode/PutByIdStatus.cpp:
(JSC::PutByIdStatus::computeFor):
* bytecode/ResolveGlobalStatus.cpp:
(JSC::ResolveGlobalStatus::computeFor):
* bytecode/ResolveOperation.h:
(JSC::ResolveOperations::ResolveOperations):
(ResolveOperations):
(JSC::PutToBaseOperation::PutToBaseOperation):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::parseResolveOperations):
(JSC::DFG::ByteCodeParser::parseBlock):
* jit/JITStubs.cpp:
(JSC::tryCachePutByID):
(JSC::tryCacheGetByID):
(JSC::DEFINE_STUB_FUNCTION):
(JSC::lazyLinkFor):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
(JSC::LLInt::setUpCall):
* runtime/JSScope.cpp:
(JSC::JSScope::resolveContainingScopeInternal):
(JSC::JSScope::resolveContainingScope):
(JSC::JSScope::resolvePut):

Source/WTF:

Reviewed by Mark Hahnenberg.

Implemented a new spinlock that is optimized for compactness, by using just a byte.
This will be useful as we start using fine-grained locking on a bunch of places.

At some point I'll make these byte-sized spinlocks into adaptive mutexes, but for
now I think it's fine to do the evil thing and use spinning particularly since we
only use them for short critical sections.

* WTF.xcodeproj/project.pbxproj:
* wtf/Atomics.h:
(WTF):
(WTF::weakCompareAndSwap):
* wtf/ByteSpinLock.h: Added.
(WTF):
(ByteSpinLock):
(WTF::ByteSpinLock::ByteSpinLock):
(WTF::ByteSpinLock::lock):
(WTF::ByteSpinLock::unlock):
(WTF::ByteSpinLock::isHeld):
* wtf/ThreadingPrimitives.h:
(WTF::pauseBriefly):
(WTF):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153122 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: value profiles and array profiles should be thread-safe enough to be accessible in a concurrent compilation thread
https://bugs.webkit.org/show_bug.cgi?id=114906

Source/JavaScriptCore:

Reviewed by Oliver Hunt.

This introduces thread safety to value profiles, array profiles, and
array allocation profiles.

We already have three separate operations that happen on profiles:
(1) writing, which the JIT, LLInt, and OSR exit do; (2) updating,
which happens during GC, from OSR entry slow-paths, and in the DFG;
and (3) reading, which happens in the DFG. For example, the JIT/LLInt
and OSR exit write to ValueProfile::m_buckets, which gets synthesized
into ValueProfile::m_prediction (and other fields) during update, and
the latter gets read by the DFG. Note that (2) must also happen in
the DFG since only the DFG knows which code blocks it will inline,
and those blocks' profiles may not have otherwise been updated via
any other mechanism.

I refer to these three operations as writing, updating, and reading.

Consequently, both profile updating and profile reading may happen
asynchronously, if the JIT is asynchronous.

The locking protocol for profiles works as follows:

- Writing does not require locking, but is only allowed on the main
  thread. We require that these fields can be stored atomically by
  the profiling code, even without locks. For value profiles, this
  only works on 64-bit platforms, currently. For array profiles,
  which consist of multiple separate fields, this means that an
  asynchronous update of the profile may see slight inconsistencies
  (like a structure that doesn't quite match the array modes bits),
  but these should be harmless: at worst, the DFG will specialize
  too much and we'll have OSR exits.

- Updating a value profile requires holding a lock, but must assume
  that the fields written by the profiling code in JIT/LLInt may
  be written to without locking.

- Reading a value profile requires holding a lock.

The one major exception to these rules is the ArrayAllocationProfile,
which requires no locking. We do this because it's used so often and
in places where we don't necessarily have access to the owning
CodeBlock, so if we did want it to be locked it would have to have
its own lock. Also, I believe that it is sound to just make this
profile racy and not worry about locking at all. All that was needed
were some changes to ensure that we explicitly read some raced-over
fields only once.

Two additional interesting things in this change:

- To make it easy to see which profile methods require locking, they
  take a const CodeBlockLocker& as an argument. I saw this idiom for
  identifying which methods require which locks to be held being used
  in LLVM, and I quite like it.

- Lazy operand value profiles, which are created lazily and at any
  time, require the CodeBlockLock to be held when they are being
  created. Writes to them are lockless and main-thread-only, but as
  with other profiles, updates and reads require locking.

* JavaScriptCore.xcodeproj/project.pbxproj:
* bytecode/ArrayAllocationProfile.cpp:
(JSC::ArrayAllocationProfile::updateIndexingType):
* bytecode/ArrayAllocationProfile.h:
(JSC::ArrayAllocationProfile::selectIndexingType):
* bytecode/ArrayProfile.cpp:
(JSC::ArrayProfile::computeUpdatedPrediction):
(JSC::ArrayProfile::briefDescription):
* bytecode/ArrayProfile.h:
(ArrayProfile):
(JSC::ArrayProfile::expectedStructure):
(JSC::ArrayProfile::structureIsPolymorphic):
(JSC::ArrayProfile::hasDefiniteStructure):
(JSC::ArrayProfile::observedArrayModes):
(JSC::ArrayProfile::mayInterceptIndexedAccesses):
(JSC::ArrayProfile::mayStoreToHole):
(JSC::ArrayProfile::outOfBounds):
(JSC::ArrayProfile::usesOriginalArrayStructures):
* bytecode/CallLinkStatus.cpp:
(JSC::CallLinkStatus::computeFor):
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::dumpValueProfiling):
(JSC::CodeBlock::dumpArrayProfiling):
(JSC::CodeBlock::updateAllPredictionsAndCountLiveness):
(JSC::CodeBlock::updateAllArrayPredictions):
* bytecode/CodeBlock.h:
(JSC::CodeBlock::valueProfilePredictionForBytecodeOffset):
(JSC::CodeBlock::updateAllPredictionsAndCheckIfShouldOptimizeNow):
(CodeBlock):
* bytecode/CodeBlockLock.h: Added.
(JSC):
* bytecode/GetByIdStatus.cpp:
(JSC::GetByIdStatus::computeFor):
* bytecode/LazyOperandValueProfile.cpp:
(JSC::CompressedLazyOperandValueProfileHolder::computeUpdatedPredictions):
(JSC::CompressedLazyOperandValueProfileHolder::add):
(JSC::LazyOperandValueProfileParser::LazyOperandValueProfileParser):
(JSC::LazyOperandValueProfileParser::~LazyOperandValueProfileParser):
(JSC):
(JSC::LazyOperandValueProfileParser::initialize):
(JSC::LazyOperandValueProfileParser::prediction):
* bytecode/LazyOperandValueProfile.h:
(CompressedLazyOperandValueProfileHolder):
(LazyOperandValueProfileParser):
* bytecode/MethodOfGettingAValueProfile.cpp:
(JSC::MethodOfGettingAValueProfile::getSpecFailBucket):
* bytecode/PutByIdStatus.cpp:
(JSC::PutByIdStatus::computeFor):
* bytecode/ResolveGlobalStatus.cpp:
(JSC::ResolveGlobalStatus::computeFor):
* bytecode/ValueProfile.h:
(JSC::ValueProfileBase::briefDescription):
(ValueProfileBase):
(JSC::ValueProfileBase::computeUpdatedPrediction):
* dfg/DFGArrayMode.cpp:
(JSC::DFG::ArrayMode::fromObserved):
* dfg/DFGArrayMode.h:
(ArrayMode):
(JSC::DFG::ArrayMode::withProfile):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::injectLazyOperandSpeculation):
(JSC::DFG::ByteCodeParser::getPredictionWithoutOSRExit):
(JSC::DFG::ByteCodeParser::getArrayMode):
(JSC::DFG::ByteCodeParser::getArrayModeAndEmitChecks):
(JSC::DFG::ByteCodeParser::parseResolveOperations):
(JSC::DFG::ByteCodeParser::parseBlock):
(JSC::DFG::ByteCodeParser::InlineStackEntry::InlineStackEntry):
* dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
* dfg/DFGOSRExitPreparation.cpp:
(JSC::DFG::prepareCodeOriginForOSRExit):
* dfg/DFGPredictionInjectionPhase.cpp:
(JSC::DFG::PredictionInjectionPhase::run):
* jit/JITInlines.h:
(JSC::JIT::chooseArrayMode):
* jit/JITStubs.cpp:
(JSC::tryCachePutByID):
(JSC::tryCacheGetByID):
(JSC::DEFINE_STUB_FUNCTION):
(JSC::lazyLinkFor):
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
(JSC::LLInt::setUpCall):
* profiler/ProfilerBytecodeSequence.cpp:
(JSC::Profiler::BytecodeSequence::BytecodeSequence):
* runtime/JSScope.cpp:
(JSC::JSScope::resolveContainingScopeInternal):
(JSC::JSScope::resolvePut):

Source/WTF:

Reviewed by Oliver Hunt.

Add ability to abstract whether or not the CodeBlock requires locking at all,
since some platforms may not support the byte spin-locking and/or may not want
to, if they turn off concurrent JIT.

* WTF.xcodeproj/project.pbxproj:
* wtf/ByteSpinLock.h:
* wtf/NoLock.h: Added.
(WTF):
(NoLock):
(WTF::NoLock::lock):
(WTF::NoLock::unlock):
(WTF::NoLock::isHeld):
* wtf/Platform.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153123 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: It should be possible to query WatchpointSets, and add Watchpoints, even if the compiler is running in another thread
https://bugs.webkit.org/show_bug.cgi?id=114909

Source/JavaScriptCore:

Reviewed by Oliver Hunt.

The idea here is that a concurrent compiler will use watchpoint sets as follows:

During concurrent compilation: It will create Watchpoints, and query WatchpointSets only
for the purpose of profiling. That is, it will use decide whether it is profitable to
compile the code "as if" the watchpoint sets are valid.

During synchronous linking: By "linking" I don't necessarily mean the LinkBuffer stuff,
but just the very bitter end of compilation where we make the JIT code callable. This
can happen after LinkBuffer stuff. Anyway, this will have to happen synchronously, and
at that point we can (a) check that all WatchpointSets that we assumed were valid are
still valid and (b) if they are then we add the watchpoints to those sets. If any of the
sets are invalid, we give up on this compilation and try again later.

The querying of WatchpointSets is engineered to say that the set is still valid if it
is so *right now*, but this is done in a racy way and so it may say so spuriously: we
may, with hopefully low probability, have a set that says it is valid even though it was
just invalidated. The goal is only to ensure that (i) a set never claims to be invalid
if it is actually valid, (ii) a set doesn't claim to be valid if it was invalidated
before compilation even began, and (iii) querying the validity of a set doesn't cause us
to crash.

* JavaScriptCore.xcodeproj/project.pbxproj:
* bytecode/Watchpoint.cpp:
(JSC::InlineWatchpointSet::inflateSlow):
* bytecode/Watchpoint.h:
(WatchpointSet):
(InlineWatchpointSet):
(JSC::InlineWatchpointSet::hasBeenInvalidated):
(JSC::InlineWatchpointSet::isThin):
(JSC::InlineWatchpointSet::isFat):
(JSC::InlineWatchpointSet::fat):
* dfg/DFGDesiredWatchpoints.cpp: Added.
(DFG):
(JSC::DFG::DesiredWatchpoints::DesiredWatchpoints):
(JSC::DFG::DesiredWatchpoints::~DesiredWatchpoints):
(JSC::DFG::DesiredWatchpoints::addLazily):
(JSC::DFG::DesiredWatchpoints::reallyAdd):
(JSC::DFG::DesiredWatchpoints::areStillValid):
* dfg/DFGDesiredWatchpoints.h: Added.
(DFG):
(JSC::DFG::WatchpointForGenericWatchpointSet::WatchpointForGenericWatchpointSet):
(WatchpointForGenericWatchpointSet):
(GenericDesiredWatchpoints):
(JSC::DFG::GenericDesiredWatchpoints::GenericDesiredWatchpoints):
(JSC::DFG::GenericDesiredWatchpoints::addLazily):
(JSC::DFG::GenericDesiredWatchpoints::reallyAdd):
(JSC::DFG::GenericDesiredWatchpoints::areStillValid):
(DesiredWatchpoints):
* dfg/DFGDriver.cpp:
(JSC::DFG::compile):
* 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/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/FTLCompile.h:
(FTL):
* ftl/FTLState.h:
(State):
* runtime/JSFunction.h:
(JSFunction):
(JSC::JSFunction::allocationProfileWatchpointSet):
* runtime/Structure.h:
(Structure):
(JSC::Structure::transitionWatchpointSet):

Source/WTF:

Reviewed by Oliver Hunt.

Harden our notions of memory fences, now that we're doing racy algorithms.

* wtf/Atomics.h:
(WTF):
(WTF::compilerFence):
(WTF::armV7_dmb):
(WTF::armV7_dmb_st):
(WTF::loadLoadFence):
(WTF::loadStoreFence):
(WTF::storeLoadFence):
(WTF::storeStoreFence):
(WTF::memoryBarrierAfterLock):
(WTF::memoryBarrierBeforeUnlock):
(WTF::x86_mfence):


Conflicts:
	Source/WTF/wtf/Atomics.h

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153124 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: developing LLVM in tandem with WebKit should be fun and easy
https://bugs.webkit.org/show_bug.cgi?id=114925

Reviewed by Geoffrey Garen.

This enables building LLVM along with WebKit, so that build-jsc and build-webkit
will also optionally build LLVM and quickly symlink LLVM's built products into
the right places.

Most WebKit and JSC hackers will want to rely on the checked-in already-built
versions of LLVM in WebKitLibraries. But developing both systems in tandem is an
increasingly common use-case for me, and it may become a common use case for a
handful of others. Currently, this is really painful: you first have to build
LLVM, then you have to export-llvm-build (which takes a while), and then you
have to make sure that your LLVM_LIBRARY_PACKAGE and LLVM_INCLUDE_PACKAGE
variables are set to point to the thing you exported. The whole process loses
track of dependencies very quickly: making a tiny change in LLVM requires
packaging, and then unpackaging, a large number of potentially large headers and
static libraries. Not only is this slow but it then causes the WebKit build
system to rebuild anything that transitively includes any LLVM header, which is
now quite a few files. While this sort of use pattern is still worthwhile if
you're trying to package a binary drop and test it, it's not great if you're
just trying to do experimental development that involves making small changes
in both trees.

This change fixes this use case while keeping the old use cases intact. You can
do tandem development using one of two modes:

Your own LLVM directory: just set LLVM_SOURCE_PATH to the *absolute* path of
the LLVM directory you're using. Once this is done, any invocation of a WebKit
build via build-jsc or build-webkit will also build LLVM, and then quickly
symlink things into place without perturbing dependency tracking.

Internal LLVM directory: if you check out llvm into a directory called 'llvm'
right off of the WebKit source tree, then the build system will automatically
use this.

Here's how this takes care of dependencies:

Headers: the include/llvm and include/llvm-c directories are symlinked into
$productsDir/usr/local/include. And then everything just works.

Libraries: the build system detects, by reading LLVM's Makefile.config, which
mode LLVM is built in (like Release+Asserts or Debug+Asserts) and symlinks
the .a files into $productsDir/<thingy>. It will ranlib those libraries only
if they have changed, by checking both the modification time and also whether
the last time we had a symlink, that symlink was from the same directory.
This helps if you switch to an *older* LLVM build (using LLVM_SOURCE_PATH)
but that build wasn't yet ranlib'd.

One problem that this does not yet solve is that xcodebuild will not relink
JavaScriptCore if the only thing that changed was the libraries. I will work
on this problem separately: https://bugs.webkit.org/show_bug.cgi?id=114926.

* Scripts/copy-webkitlibraries-to-product-directory:
(unpackIfNecessary):
(fileContains):
(fileContentsEquals):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153125 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: WebKit's build system should relink JavaScriptCore if LLVM's libraries changed but its headers didn't
https://bugs.webkit.org/show_bug.cgi?id=114926

Source/JavaScriptCore:

Reviewed by Geoffrey Garen.

Use a phony file that includes a phony header to force JavaScriptCore to be relinked
if necessary. The external LLVM-importing scripts will touch the header if the libraries
are known to have changed.

* JavaScriptCore.xcodeproj/project.pbxproj:
* ftl/WebKitLLVMLibraryAnchor.cpp: Added.

Tools:

Reviewed by Geoffrey Garen.

If the LLVM libraries change, then touch a phony header, which will force relink
of JavaScriptCore.

* Scripts/copy-webkitlibraries-to-product-directory:
(unpackIfNecessary):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153126 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: tandem WebKit and LLVM builds should ./configure LLVM if needed
https://bugs.webkit.org/show_bug.cgi?id=114933

Reviewed by Andy Estes.

This makes it easy to get set up for tandem LLVM builds.

* Scripts/copy-webkitlibraries-to-product-directory:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153127 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: Create an equivalent of Structure::get() that can work from a compilation thread
https://bugs.webkit.org/show_bug.cgi?id=114987

Reviewed by Geoffrey Garen.

This completes the work started by r148570. That patch made it possible to do
Structure::get() without modifying Structure. This patch takes this further, and
makes this thread-safe (for non-uncacheable-dictionaries) via
Structure::getConcurrently(). This method not only doesn't modify Structure, but
also ensures that any concurrent attempts to add to, remove from, or steal the
table from that structure doesn't mess up the result of the call. The call may
return invalidOffset even if a property is *just* about to be added, but it will
never do the reverse: if it returns a property then you can be sure that the
structure really does have that property and always will have it.

* bytecode/GetByIdStatus.cpp:
(JSC::GetByIdStatus::computeFromLLInt):
(JSC::GetByIdStatus::computeForChain):
(JSC::GetByIdStatus::computeFor):
* bytecode/PutByIdStatus.cpp:
(JSC::PutByIdStatus::computeFromLLInt):
(JSC::PutByIdStatus::computeFor):
* dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::isStringPrototypeMethodSane):
* runtime/PropertyMapHashTable.h:
(PropertyTable):
(JSC::PropertyTable::findConcurrently):
(JSC):
(JSC::PropertyTable::add):
(JSC::PropertyTable::remove):
(JSC::PropertyTable::reinsert):
(JSC::PropertyTable::rehash):
* runtime/PropertyTable.cpp:
(JSC::PropertyTable::PropertyTable):
* runtime/Structure.cpp:
(JSC::Structure::findStructuresAndMapForMaterialization):
(JSC::Structure::getConcurrently):
* runtime/Structure.h:
(Structure):
* runtime/StructureInlines.h:
(JSC::Structure::getConcurrently):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153128 268f45cc-cd09-0410-ab3c-d52691b4dbfc
fourthTier: AbstractValue methods that deal with watchpoints should have access to Graph, so that in debug mode, Graph can track the history of watchpoint states and detect races
https://bugs.webkit.org/show_bug.cgi?id=115084

Reviewed by Geoffrey Garen.

The idea is that as part of https://bugs.webkit.org/show_bug.cgi?id=115083, I'll have
Graph record the initial state of a watchpoint at the time that we decide to take
advantage of it; then I will use this to disable any watchpoint-related assertions
in debug mode. Note that this "watchpoint cache" will only be maintained in debug
mode, so there will be no release performance implications. But to do this, I need to
ensure that all of the places that reason about watchpoints have access to Graph.
For example, I'll want AbstractValue::setFuturePossibleStructure to record the state
of the watchpoint in Graph so that subsequent assertions can check if the watchpoint's
state had changed since that decision was made.

* JavaScriptCore.xcodeproj/project.pbxproj:
* dfg/DFGAbstractState.cpp:
(JSC::DFG::AbstractState::initialize):
(JSC::DFG::AbstractState::executeEffects):
(JSC::DFG::AbstractState::mergeStateAtTail):
* dfg/DFGAbstractState.h:
(JSC::DFG::AbstractState::trySetConstant):
* dfg/DFGAbstractValue.cpp: Added.
(DFG):
(JSC::DFG::AbstractValue::setMostSpecific):
(JSC::DFG::AbstractValue::set):
(JSC::DFG::AbstractValue::filter):
(JSC::DFG::AbstractValue::setFuturePossibleStructure):
(JSC::DFG::AbstractValue::filterFuturePossibleStructure):
(JSC::DFG::AbstractValue::dump):
* dfg/DFGAbstractValue.h:
(DFG):
(AbstractValue):
(JSC::DFG::AbstractValue::setType):
(JSC::DFG::AbstractValue::filterByValue):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153129 268f45cc-cd09-0410-ab3c-d52691b4dbfc
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
fourthTier: WatchpointSet should make racy uses easier to reason about
https://bugs.webkit.org/show_bug.cgi?id=115299

Reviewed by Anders Carlsson.

The compiler often does things like:

1c) Observe something that would imply that a WatchpointSet ought to be invalid

2c) Check that it is invalid

The main thread often does things like:

1m) Fire the watchpoint set

2m) Do some other thing that would cause the compiler to assume that the WatchpointSet
ought to be invalid

An example is structure transitions, where (1c) is the compiler noticing that a
put_by_id inline cache is in a transition state, with the source structure being S;
(2c) is the compiler asserting that S's watchpoint set is invalid; (1m) is the main
thread firing S's watchpoint set before it does the first transition away from S; and
(2m) is the main thread caching the put_by_id transition away from S.

This is totally fine, except that (1c) and (2c), and (1m) and (2m) could be reordered.
Probably, in most cases, this ought to do enough things that the main thread probably
already has some fencing. But the compiler thread definitely doesn't have fencing. In
any case, we should play it safe and just have additional fencing in all of the
relevant places.

We already have some idioms to put load-load and store-store fences in the right
places. But this change just makes WatchpointSet take care of this for us, thus
reducing the chances of us getting this wrong.

* bytecode/Watchpoint.cpp:
(JSC::WatchpointSet::notifyWriteSlow):
* bytecode/Watchpoint.h:
(WatchpointSet):
(JSC::WatchpointSet::isStillValid):
(JSC::WatchpointSet::hasBeenInvalidated):
(JSC::InlineWatchpointSet::hasBeenInvalidated):
(JSC::InlineWatchpointSet::notifyWrite):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::parseBlock):
* dfg/DFGDesiredWatchpoints.h:
(JSC::DFG::GenericDesiredWatchpoints::shouldAssumeMixedState):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153131 268f45cc-cd09-0410-ab3c-d52691b4dbfc