WebAssembly: no VM / JS version of everything but Instance
https://bugs.webkit.org/show_bug.cgi?id=177473
Reviewed by Filip Pizlo, Saam Barati.
JSTests:
- Exceeding max on memory growth now returns a range error as per
spec. This is a (very minor) breaking change: it used to throw OOM
error. Update the corresponding test.
- wasm/js-api/memory-grow.js:
(assertEq):
(assert.throws):
Source/JavaScriptCore:
This change entails cleaning up and splitting a bunch of code which we had
intertwined between C++ classes which represent JS objects, and pure C++
implementation objects. This specific change goes most of the way towards
allowing JSC's WebAssembly to work without VM / JS, up to but excluding
JSWebAssemblyInstance (there's Wasm::Instance, but it's not *the* thing
yet). Because of this we still have a few FIXME identifying places that need to
change. A follow-up change will go the rest of the way.
I went about this change in the simplest way possible: grep the
JavaScriptCore/wasm directory for "JS[C_]" as well as "VM" and exclude the /js/
sub-directory (which contains the JS implementation of WebAssembly).
None of this change removes the need for a JIT entitlement to be able to use
WebAssembly. We don't have an interpreter, the process therefore still needs to
be allowed to JIT to use these pure-C++ APIs.
Interesting things to note:
- Remove VM from Plan and associated places. It can just live as a capture in
the callback lambda if it's needed.
- Wasm::Memory shouldn't require a VM. It was only used to ask the GC to
collect. We now instead pass two lambdas at construction time for this
purpose: one to notify of memory pressure, and the other to ask for
syncrhonous memory reclamation. This allows whoever creates the memory to
dictate how to react to both these cases, and for a JS embedding that's to
call the GC (async or sync, respectively).
- Move grow logic from JSWebAssemblyMemory to Wasm::Memory::grow. Use Expected
there, with an enum class for failure types.
- Exceeding max on memory growth now returns a range error as per spec. This
is a (very minor) breaking change: it used to throw OOM error. Update the
corresponding test.
- When generating the grow_memory opcode, no need to get the VM. Instead,
reach directly for Wasm::Memory and grow it.
- JSWebAssemblyMemory::grow can now always throw on failure, because it's only
ever called from JS (not from grow_memory as before).
- Wasm::Memory now takes a callback for successful growth. This allows JS
wrappers to register themselves when growth succeeds without Wasm::Memory
knowning anything about JS. It'll also allow creating a list of callbacks
for when we add thread support (we'll want to notify many wrappers, all
under a lock).
- Wasm::Memory is now back to being the source of truth about address / size,
used directly by generated code instead of JSWebAssemblyMemory.
- Move wasmToJS from the general WasmBinding header to its own header under
wasm/js. It's only used by wasm/js/JSWebAssemblyCodeBlock.cpp, and uses VM,
and therefore isn't general WebAssembly.
- Make Wasm::Context an actual type (just a struct holding a
JSWebAssemlyInstance for now) instead of an alias for that. Notably this
doesn't add anything to the Context and doesn't change what actually gets
passed around in JIT code (fast TLS or registers) because these changes
potentially impact performance. The entire purpose of this change is to
allow passing Wasm::Context around without having to know about VM. Since VM
contains a Wasm::Context the JS embedding is effectively the same, but with
this setup a non-JS embedding is much better off.
- Move JSWebAssembly into the JS folder.
- OMGPlan: use Wasm::CodeBlock directly instead of JSWebAssemblyCodeBlock.
- wasm->JS stubs are now on the instance's tail as raw pointers, instead of
being on JSWebAssemblyCodeBlock, and are now called wasm->Embedder
stubs. The owned reference is still on JSWebAssemblyCodeBlock, and is still
called wasm->JS stub. This move means that the embedder must, after creating
a Wasm::CodeBlock, somehow create the stubs to call back into the
embedder. This removes an indirection in the generated code because
the B3 IR generator now reaches into the instance instead of
JSWebAssemblyCodeBlock.
- Move more CodeBlock things. Compilation completion is now marked by its own
atomic<bool> flag instead of a nullptr plan: that required using a lock, and
was causing a deadlock in stack-trace.js because before my changes
JSWebAssemblyCodeBlock did its own completion checking separately from
Wasm::CodeBlock, without getting the lock. Now that everything points to
Wasm::CodeBlock and there's no cached completion marker, the lock was being
acquired in a sanity-check assertion.
- Embedder -> Wasm wrappers are now generated through a function that's passed
in at compilation time, instead of being hard-coded as a JS -> Wasm wrapper.
- WasmMemory doens't need to know about fault handling thunks. Only the IR
generator should know, and should make sure that the exception throwing
thunk is generated if any memory is present (note: with signal handling not
all of them generate an exception check).
- Make exception throwing pluggable: instead of having a hard-coded
JS-specific lambda we now have a regular C++ function being called from JIT
code when a WebAssembly exception is thrown. This allows any embedder to get
called as they wish. For now a process can only have a single of these
functions (i.e. only one embedder per process) because the trap handler is a
singleton. That can be fixed in in #177475.
- Create WasmEmbedder.h where all embedder plugging will live.
- Split up JSWebAssemblyTable into Wasm::Table which is
refcounted. JSWebAssemblyTable now only contains the JS functions in the
table, and Wasm::Table is what's used by the JIT code to lookup where to
call and do the instance check (for context switch). Note that this creates
an extra allocation for all the instances in Wasm::Table, and in exchange
removes an indirection in JIT code because the instance used to be obtained
off of the JS function. Also note that it's the embedder than keeps the
instances alive, not Wasm::Table (which holds a dumb pointer to the
instance), because doing otherwise would cause reference cycles.
- Add WasmInstance. It doesn't do much for now, owns globals.
- JSWebAssembly instance now doesn't just contain the imported functions as
JSObjects, it also has the corresponding import's instance and wasm
entrypoint. This triples the space allocated per instance's imported
function, but there shouldn't be that many imports. This has two upsides: it
creates smaller and faster code, and makes is easier to disassociate
embedder-specific things from embedder-neutral things. The small / faster
win is in two places: B3 IR generator only needs offsetOfImportFunction for
the call opcode (when the called index is an import) to know whether the
import is wasm->wasm or wasm->embedder (this isn't known at compile-time
because it's dependent on the import object), this is now done by seeing if
that import function has an associated target instance (only wasm->wasm
does); the other place is wasmBinding which uses offsetOfImportFunction to
figure out the wasm->wasm target instance, and then gets
WebAssemblyFunction::offsetOfWasmEntrypointLoadLocation to do a tail
call. The disassociation comes because the target instance can be
Wasm::Instance once we change what the Context is, and
WasmEntrypointLoadLocation is already embedder-independent. As a next step I
can move this tail allocation from JSWebAssemblyInstance to Wasm::Instance,
and leave importFunction in as an opaque pointer which is embedder-specific,
and in JS will remain WriteBarrier<JSObject>.
- Rename VMEntryFrame to EntryFrame, and in many places pass a pointer to it
around instead of VM. This is a first step in allowing entry frames which
aren't stored on VM, but which are instead stored in an embedder-specific
location. That change won't really affect JS except through code churn, but
will allow WebAssembly to use some machinery in a generic manner without
having a VM.
- JavaScriptCore.xcodeproj/project.pbxproj:
- Sources.txt:
- bytecode/PolymorphicAccess.cpp:
(JSC::AccessGenerationState::emitExplicitExceptionHandler):
(JSC::Debugger::stepOutOfFunction):
(JSC::Debugger::returnEvent):
(JSC::Debugger::unwindEvent):
(JSC::Debugger::didExecuteProgram):
(JSC::DFG::JITCompiler::compileExceptionHandlers):
(JSC::DFG::prepareOSREntry):
(JSC::DFG::OSRExit::compileOSRExit):
(JSC::DFG::OSRExit::compileExit):
(JSC::DFG::osrEntryThunkGenerator):
(JSC::FTL::compile):
(JSC::FTL::link):
(JSC::FTL::DFG::LowerDFGToB3::lower):
- ftl/FTLOSRExitCompiler.cpp:
(JSC::FTL::compileStub):
- interpreter/CallFrame.cpp:
(JSC::CallFrame::wasmAwareLexicalGlobalObject):
(JSC::CallFrame::callerFrame):
(JSC::CallFrame::unsafeCallerFrame):
(JSC::ExecState::callerFrame const):
(JSC::ExecState::callerFrameOrEntryFrame const):
(JSC::ExecState::unsafeCallerFrameOrEntryFrame const):
- interpreter/FrameTracers.h:
(JSC::NativeCallFrameTracer::NativeCallFrameTracer):
(JSC::NativeCallFrameTracerWithRestore::NativeCallFrameTracerWithRestore):
(JSC::NativeCallFrameTracerWithRestore::~NativeCallFrameTracerWithRestore):
- interpreter/Interpreter.cpp:
(JSC::UnwindFunctor::operator() const):
(JSC::UnwindFunctor::copyCalleeSavesToEntryFrameCalleeSavesBuffer const):
(JSC::Interpreter::unwind):
- interpreter/StackVisitor.cpp:
(JSC::StackVisitor::StackVisitor):
(JSC::StackVisitor::gotoNextFrame):
(JSC::StackVisitor::readNonInlinedFrame):
(JSC::StackVisitor::Frame::dump const):
- interpreter/StackVisitor.h:
(JSC::StackVisitor::Frame::callerIsEntryFrame const):
- interpreter/VMEntryRecord.h:
(JSC::VMEntryRecord::prevTopEntryFrame):
(JSC::VMEntryRecord::unsafePrevTopEntryFrame):
(JSC::EntryFrame::vmEntryRecordOffset):
(JSC::AssemblyHelpers::restoreCalleeSavesFromEntryFrameCalleeSavesBuffer):
(JSC::AssemblyHelpers::loadWasmContextInstance):
(JSC::AssemblyHelpers::storeWasmContextInstance):
(JSC::AssemblyHelpers::loadWasmContextInstanceNeedsMacroScratchRegister):
(JSC::AssemblyHelpers::storeWasmContextInstanceNeedsMacroScratchRegister):
(JSC::AssemblyHelpers::copyCalleeSavesToEntryFrameCalleeSavesBufferImpl):
(JSC::AssemblyHelpers::copyCalleeSavesToVMEntryFrameCalleeSavesBuffer):
(JSC::AssemblyHelpers::copyCalleeSavesToEntryFrameCalleeSavesBuffer):
(JSC::AssemblyHelpers::copyCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer):
(JSC::JIT::emitEnterOptimizationCheck):
(JSC::JIT::privateCompileExceptionHandlers):
(JSC::genericUnwind):
(JSC::JIT::emit_op_throw):
(JSC::JIT::emit_op_catch):
(JSC::JIT::emitSlow_op_loop_hint):
(JSC::JIT::emit_op_throw):
(JSC::JIT::emit_op_catch):
- jit/JITOperations.cpp:
- jit/ThunkGenerators.cpp:
(JSC::throwExceptionFromCallSlowPathGenerator):
(JSC::nativeForGenerator):
(functionDumpCallFrame):
- llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
(JSC::vmEntryRecord):
- llint/LowLevelInterpreter.asm:
- llint/LowLevelInterpreter32_64.asm:
- llint/LowLevelInterpreter64.asm:
- runtime/Options.cpp:
(JSC::recomputeDependentOptions):
- runtime/Options.h:
- runtime/SamplingProfiler.cpp:
(JSC::FrameWalker::FrameWalker):
(JSC::FrameWalker::advanceToParentFrame):
(JSC::SamplingProfiler::processUnverifiedStackTraces):
(JSC::ThrowScope::~ThrowScope):
(JSC::VM::VM):
(JSC::VM::~VM):
(JSC::VM::topEntryFrameOffset):
(JSC::isSaneFrame):
(JSC::VMTraps::tryInstallTrapBreakpoints):
(JSC::VMTraps::invalidateCodeBlocksOnStack):
- wasm/WasmB3IRGenerator.cpp:
(JSC::Wasm::B3IRGenerator::restoreWasmContextInstance):
(JSC::Wasm::B3IRGenerator::B3IRGenerator):
(JSC::Wasm::B3IRGenerator::restoreWebAssemblyGlobalState):
(JSC::Wasm::B3IRGenerator::addGrowMemory):
(JSC::Wasm::B3IRGenerator::addCurrentMemory):
(JSC::Wasm::B3IRGenerator::addCall):
(JSC::Wasm::B3IRGenerator::addCallIndirect):
(JSC::Wasm::parseAndCompile):
- wasm/WasmB3IRGenerator.h:
- wasm/WasmBBQPlan.cpp:
(JSC::Wasm::BBQPlan::BBQPlan):
(JSC::Wasm::BBQPlan::compileFunctions):
(JSC::Wasm::BBQPlan::complete):
- wasm/WasmBBQPlan.h:
- wasm/WasmBBQPlanInlines.h:
(JSC::Wasm::BBQPlan::initializeCallees):
(JSC::Wasm::wasmToWasm):
- wasm/WasmBinding.h:
- wasm/WasmCodeBlock.cpp:
(JSC::Wasm::CodeBlock::create):
(JSC::Wasm::CodeBlock::CodeBlock):
(JSC::Wasm::CodeBlock::compileAsync):
(JSC::Wasm::CodeBlock::setCompilationFinished):
(JSC::Wasm::CodeBlock::offsetOfImportStubs):
(JSC::Wasm::CodeBlock::allocationSize):
(JSC::Wasm::CodeBlock::importWasmToEmbedderStub):
(JSC::Wasm::CodeBlock::offsetOfImportWasmToEmbedderStub):
(JSC::Wasm::CodeBlock::wasmToJSCallStubForImport):
(JSC::Wasm::CodeBlock::compilationFinished):
(JSC::Wasm::CodeBlock::jsEntrypointCalleeFromFunctionIndexSpace):
(JSC::Wasm::CodeBlock::wasmEntrypointCalleeFromFunctionIndexSpace):
(JSC::Wasm::Context::useFastTLS):
(JSC::Wasm::Context::load const):
(JSC::Wasm::Context::store):
- wasm/WasmContext.h:
- wasm/WasmEmbedder.h: Copied from Source/JavaScriptCore/wasm/WasmContext.h.
- wasm/WasmFaultSignalHandler.cpp:
- wasm/WasmFaultSignalHandler.h:
- wasm/WasmFormat.h:
- wasm/WasmInstance.cpp: Copied from Source/JavaScriptCore/wasm/WasmFaultSignalHandler.h.
(JSC::Wasm::Instance::Instance):
(JSC::Wasm::Instance::~Instance):
(JSC::Wasm::Instance::extraMemoryAllocated const):
- wasm/WasmInstance.h: Added.
(JSC::Wasm::Instance::create):
(JSC::Wasm::Instance::finalizeCreation):
(JSC::Wasm::Instance::module):
(JSC::Wasm::Instance::codeBlock):
(JSC::Wasm::Instance::memory):
(JSC::Wasm::Instance::table):
(JSC::Wasm::Instance::loadI32Global const):
(JSC::Wasm::Instance::loadI64Global const):
(JSC::Wasm::Instance::loadF32Global const):
(JSC::Wasm::Instance::loadF64Global const):
(JSC::Wasm::Instance::setGlobal):
(JSC::Wasm::Instance::offsetOfCachedStackLimit):
(JSC::Wasm::Instance::cachedStackLimit const):
(JSC::Wasm::Instance::setCachedStackLimit):
(JSC::Wasm::Memory::Memory):
(JSC::Wasm::Memory::create):
(JSC::Wasm::Memory::~Memory):
(JSC::Wasm::Memory::grow):
(JSC::Wasm::Memory::offsetOfMemory):
(JSC::Wasm::Memory::offsetOfSize):
- wasm/WasmMemoryInformation.cpp:
(JSC::Wasm::PinnedRegisterInfo::get):
(JSC::Wasm::PinnedRegisterInfo::PinnedRegisterInfo):
- wasm/WasmMemoryInformation.h:
(JSC::Wasm::PinnedRegisterInfo::toSave const):
- wasm/WasmMemoryMode.cpp: Copied from Source/JavaScriptCore/wasm/WasmFaultSignalHandler.h.
(JSC::Wasm::makeString):
- wasm/WasmMemoryMode.h: Copied from Source/JavaScriptCore/wasm/WasmFaultSignalHandler.h.
- wasm/WasmModule.cpp:
(JSC::Wasm::makeValidationCallback):
(JSC::Wasm::Module::validateSync):
(JSC::Wasm::Module::validateAsync):
(JSC::Wasm::Module::getOrCreateCodeBlock):
(JSC::Wasm::Module::compileSync):
(JSC::Wasm::Module::compileAsync):
- wasm/WasmModule.h:
- wasm/WasmModuleParser.cpp:
(JSC::Wasm::ModuleParser::parseTableHelper):
(JSC::Wasm::OMGPlan::OMGPlan):
(JSC::Wasm::OMGPlan::runForIndex):
- wasm/WasmOMGPlan.h:
- wasm/WasmPageCount.h:
(JSC::Wasm::PageCount::isValid const):
(JSC::Wasm::Plan::Plan):
(JSC::Wasm::Plan::runCompletionTasks):
(JSC::Wasm::Plan::addCompletionTask):
(JSC::Wasm::Plan::tryRemoveContextAndCancelIfLast):
(JSC::Wasm::Plan::dontFinalize):
- wasm/WasmSignature.cpp:
- wasm/WasmSignature.h:
- wasm/WasmTable.cpp: Added.
(JSC::Wasm::Table::create):
(JSC::Wasm::Table::~Table):
(JSC::Wasm::Table::Table):
(JSC::Wasm::Table::grow):
(JSC::Wasm::Table::clearFunction):
(JSC::Wasm::Table::setFunction):
- wasm/WasmTable.h: Copied from Source/JavaScriptCore/wasm/js/JSWebAssemblyTable.h.
(JSC::Wasm::Table::maximum const):
(JSC::Wasm::Table::size const):
(JSC::Wasm::Table::offsetOfSize):
(JSC::Wasm::Table::offsetOfFunctions):
(JSC::Wasm::Table::offsetOfInstances):
(JSC::Wasm::Table::isValidSize):
(JSC::Wasm::throwExceptionFromWasmThunkGenerator):
(JSC::Wasm::triggerOMGTierUpThunkGenerator):
(JSC::Wasm::Thunks::setThrowWasmException):
(JSC::Wasm::Thunks::throwWasmException):
- wasm/WasmThunks.h:
- wasm/WasmWorklist.cpp:
(JSC::Wasm::Worklist::stopAllPlansForContext):
- wasm/WasmWorklist.h:
- wasm/js/JSToWasm.cpp: Added.
(JSC::Wasm::createJSToWasmWrapper):
- wasm/js/JSToWasm.h: Copied from Source/JavaScriptCore/wasm/WasmBinding.h.
- wasm/js/JSWebAssembly.cpp: Renamed from Source/JavaScriptCore/wasm/JSWebAssembly.cpp.
- wasm/js/JSWebAssembly.h: Renamed from Source/JavaScriptCore/wasm/JSWebAssembly.h.
- wasm/js/JSWebAssemblyCodeBlock.cpp:
(JSC::JSWebAssemblyCodeBlock::create):
(JSC::JSWebAssemblyCodeBlock::JSWebAssemblyCodeBlock):
- wasm/js/JSWebAssemblyCodeBlock.h:
- wasm/js/JSWebAssemblyInstance.cpp:
(JSC::JSWebAssemblyInstance::JSWebAssemblyInstance):
(JSC::JSWebAssemblyInstance::finishCreation):
(JSC::JSWebAssemblyInstance::visitChildren):
(JSC::JSWebAssemblyInstance::finalizeCreation):
(JSC::JSWebAssemblyInstance::create):
- wasm/js/JSWebAssemblyInstance.h:
(JSC::JSWebAssemblyInstance::instance):
(JSC::JSWebAssemblyInstance::context const):
(JSC::JSWebAssemblyInstance::table):
(JSC::JSWebAssemblyInstance::webAssemblyToJSCallee):
(JSC::JSWebAssemblyInstance::setMemory):
(JSC::JSWebAssemblyInstance::offsetOfTail):
(JSC::JSWebAssemblyInstance::importFunctionInfo):
(JSC::JSWebAssemblyInstance::offsetOfTargetInstance):
(JSC::JSWebAssemblyInstance::offsetOfWasmEntrypoint):
(JSC::JSWebAssemblyInstance::offsetOfImportFunction):
(JSC::JSWebAssemblyInstance::importFunction):
(JSC::JSWebAssemblyInstance::internalMemory):
(JSC::JSWebAssemblyInstance::wasmCodeBlock const):
(JSC::JSWebAssemblyInstance::offsetOfWasmTable):
(JSC::JSWebAssemblyInstance::offsetOfCallee):
(JSC::JSWebAssemblyInstance::offsetOfGlobals):
(JSC::JSWebAssemblyInstance::offsetOfWasmCodeBlock):
(JSC::JSWebAssemblyInstance::offsetOfWasmMemory):
(JSC::JSWebAssemblyInstance::cachedStackLimit const):
(JSC::JSWebAssemblyInstance::setCachedStackLimit):
(JSC::JSWebAssemblyInstance::wasmMemory):
(JSC::JSWebAssemblyInstance::wasmModule):
(JSC::JSWebAssemblyInstance::allocationSize):
(JSC::JSWebAssemblyInstance::module const):
- wasm/js/JSWebAssemblyMemory.cpp:
(JSC::JSWebAssemblyMemory::create):
(JSC::JSWebAssemblyMemory::adopt):
(JSC::JSWebAssemblyMemory::JSWebAssemblyMemory):
(JSC::JSWebAssemblyMemory::grow):
(JSC::JSWebAssemblyMemory::growSuccessCallback):
- wasm/js/JSWebAssemblyMemory.h:
- wasm/js/JSWebAssemblyModule.cpp:
(JSC::JSWebAssemblyModule::moduleInformation const):
(JSC::JSWebAssemblyModule::exportSymbolTable const):
(JSC::JSWebAssemblyModule::signatureIndexFromFunctionIndexSpace const):
(JSC::JSWebAssemblyModule::callee const):
(JSC::JSWebAssemblyModule::codeBlock):
(JSC::JSWebAssemblyModule::module):
- wasm/js/JSWebAssemblyModule.h:
- wasm/js/JSWebAssemblyTable.cpp:
(JSC::JSWebAssemblyTable::create):
(JSC::JSWebAssemblyTable::JSWebAssemblyTable):
(JSC::JSWebAssemblyTable::visitChildren):
(JSC::JSWebAssemblyTable::grow):
(JSC::JSWebAssemblyTable::getFunction):
(JSC::JSWebAssemblyTable::clearFunction):
(JSC::JSWebAssemblyTable::setFunction):
- wasm/js/JSWebAssemblyTable.h:
(JSC::JSWebAssemblyTable::isValidSize):
(JSC::JSWebAssemblyTable::maximum const):
(JSC::JSWebAssemblyTable::size const):
(JSC::JSWebAssemblyTable::table):
- wasm/js/WasmToJS.cpp: Copied from Source/JavaScriptCore/wasm/WasmBinding.cpp.
(JSC::Wasm::materializeImportJSCell):
(JSC::Wasm::wasmToJS):
(JSC::Wasm::wasmToJSException):
- wasm/js/WasmToJS.h: Copied from Source/JavaScriptCore/wasm/WasmBinding.h.
- wasm/js/WebAssemblyFunction.cpp:
(JSC::callWebAssemblyFunction):
- wasm/js/WebAssemblyInstanceConstructor.cpp:
(JSC::constructJSWebAssemblyInstance):
- wasm/js/WebAssemblyMemoryConstructor.cpp:
(JSC::constructJSWebAssemblyMemory):
- wasm/js/WebAssemblyMemoryPrototype.cpp:
(JSC::webAssemblyMemoryProtoFuncGrow):
- wasm/js/WebAssemblyModuleConstructor.cpp:
(JSC::constructJSWebAssemblyModule):
(JSC::WebAssemblyModuleConstructor::createModule):
- wasm/js/WebAssemblyModuleConstructor.h:
- wasm/js/WebAssemblyModuleRecord.cpp:
(JSC::WebAssemblyModuleRecord::link):
(JSC::WebAssemblyModuleRecord::evaluate):
- wasm/js/WebAssemblyPrototype.cpp:
(JSC::webAssemblyCompileFunc):
(JSC::instantiate):
(JSC::compileAndInstantiate):
(JSC::webAssemblyValidateFunc):
- wasm/js/WebAssemblyTableConstructor.cpp:
(JSC::constructJSWebAssemblyTable):
- wasm/js/WebAssemblyWrapperFunction.cpp:
(JSC::WebAssemblyWrapperFunction::create):
Source/WebCore:
- ForwardingHeaders/wasm/WasmModule.h: Added. This used to be
included in JSWebAssemblyModule.h.
- bindings/js/SerializedScriptValue.cpp: Update postMessage code
according to C++ API changes.
