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Diffstat (limited to 'js/src/vm/GeneratorObject.cpp')
| -rw-r--r-- | js/src/vm/GeneratorObject.cpp | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/js/src/vm/GeneratorObject.cpp b/js/src/vm/GeneratorObject.cpp new file mode 100644 index 0000000000..08f1ebd948 --- /dev/null +++ b/js/src/vm/GeneratorObject.cpp @@ -0,0 +1,508 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "vm/GeneratorObject.h" + +#include "frontend/ParserAtom.h" +#ifdef DEBUG +# include "js/friend/DumpFunctions.h" // js::DumpObject, js::DumpValue +#endif +#include "js/PropertySpec.h" +#include "vm/AsyncFunction.h" +#include "vm/AsyncIteration.h" +#include "vm/FunctionFlags.h" // js::FunctionFlags +#include "vm/GlobalObject.h" +#include "vm/JSObject.h" +#include "vm/PlainObject.h" // js::PlainObject + +#include "debugger/DebugAPI-inl.h" +#include "vm/Stack-inl.h" + +using namespace js; + +AbstractGeneratorObject* AbstractGeneratorObject::create( + JSContext* cx, HandleFunction callee, HandleScript script, + HandleObject environmentChain, Handle<ArgumentsObject*> argsObject) { + Rooted<AbstractGeneratorObject*> genObj(cx); + if (!callee->isAsync()) { + genObj = GeneratorObject::create(cx, callee); + } else if (callee->isGenerator()) { + genObj = AsyncGeneratorObject::create(cx, callee); + } else { + genObj = AsyncFunctionGeneratorObject::create(cx, callee); + } + if (!genObj) { + return nullptr; + } + + genObj->setCallee(*callee); + genObj->setEnvironmentChain(*environmentChain); + if (argsObject) { + genObj->setArgsObj(*argsObject.get()); + } + + ArrayObject* stack = NewDenseFullyAllocatedArray(cx, script->nslots()); + if (!stack) { + return nullptr; + } + + genObj->setStackStorage(*stack); + + // Note: This assumes that a Warp frame cannot be the target of + // the debugger, as we do not call OnNewGenerator. + return genObj; +} + +JSObject* AbstractGeneratorObject::createFromFrame(JSContext* cx, + AbstractFramePtr frame) { + MOZ_ASSERT(frame.isGeneratorFrame()); + MOZ_ASSERT(!frame.isConstructing()); + + if (frame.isModuleFrame()) { + return createModuleGenerator(cx, frame); + } + + RootedFunction fun(cx, frame.callee()); + Rooted<ArgumentsObject*> maybeArgs( + cx, frame.script()->needsArgsObj() ? &frame.argsObj() : nullptr); + RootedObject environmentChain(cx, frame.environmentChain()); + + RootedScript script(cx, frame.script()); + Rooted<AbstractGeneratorObject*> genObj( + cx, AbstractGeneratorObject::create(cx, fun, script, environmentChain, + maybeArgs)); + if (!genObj) { + return nullptr; + } + + if (!DebugAPI::onNewGenerator(cx, frame, genObj)) { + return nullptr; + } + + return genObj; +} + +JSObject* AbstractGeneratorObject::createModuleGenerator( + JSContext* cx, AbstractFramePtr frame) { + Rooted<ModuleObject*> module(cx, frame.script()->module()); + Rooted<AbstractGeneratorObject*> genObj(cx); + genObj = AsyncFunctionGeneratorObject::create(cx, module); + if (!genObj) { + return nullptr; + } + + // Create a handler function to wrap the module's script. This way + // we can access it later and restore the state. + Handle<PropertyName*> funName = cx->names().empty; + RootedFunction handlerFun( + cx, NewFunctionWithProto(cx, nullptr, 0, + FunctionFlags::INTERPRETED_GENERATOR_OR_ASYNC, + nullptr, funName, nullptr, + gc::AllocKind::FUNCTION, GenericObject)); + if (!handlerFun) { + return nullptr; + } + handlerFun->initScript(module->script()); + + genObj->setCallee(*handlerFun); + genObj->setEnvironmentChain(*frame.environmentChain()); + + ArrayObject* stack = + NewDenseFullyAllocatedArray(cx, module->script()->nslots()); + if (!stack) { + return nullptr; + } + + genObj->setStackStorage(*stack); + + if (!DebugAPI::onNewGenerator(cx, frame, genObj)) { + return nullptr; + } + + return genObj; +} + +void AbstractGeneratorObject::trace(JSTracer* trc) { + DebugAPI::traceGeneratorFrame(trc, this); +} + +bool AbstractGeneratorObject::suspend(JSContext* cx, HandleObject obj, + AbstractFramePtr frame, + const jsbytecode* pc, unsigned nvalues) { + MOZ_ASSERT(JSOp(*pc) == JSOp::InitialYield || JSOp(*pc) == JSOp::Yield || + JSOp(*pc) == JSOp::Await); + + auto genObj = obj.as<AbstractGeneratorObject>(); + MOZ_ASSERT(!genObj->hasStackStorage() || genObj->isStackStorageEmpty()); + MOZ_ASSERT_IF(JSOp(*pc) == JSOp::Await, genObj->callee().isAsync()); + MOZ_ASSERT_IF(JSOp(*pc) == JSOp::Yield, genObj->callee().isGenerator()); + + if (nvalues > 0) { + ArrayObject* stack = nullptr; + MOZ_ASSERT(genObj->hasStackStorage()); + stack = &genObj->stackStorage(); + MOZ_ASSERT(stack->getDenseCapacity() >= nvalues); + if (!frame.saveGeneratorSlots(cx, nvalues, stack)) { + return false; + } + } + + genObj->setResumeIndex(pc); + genObj->setEnvironmentChain(*frame.environmentChain()); + return true; +} + +#ifdef DEBUG +void AbstractGeneratorObject::dump() const { + fprintf(stderr, "(AbstractGeneratorObject*) %p {\n", (void*)this); + fprintf(stderr, " callee: (JSFunction*) %p,\n", (void*)&callee()); + fprintf(stderr, " environmentChain: (JSObject*) %p,\n", + (void*)&environmentChain()); + if (hasArgsObj()) { + fprintf(stderr, " argsObj: Some((ArgumentsObject*) %p),\n", + (void*)&argsObj()); + } else { + fprintf(stderr, " argsObj: None,\n"); + } + if (hasStackStorage()) { + fprintf(stderr, " stackStorage: Some(ArrayObject {\n"); + ArrayObject& stack = stackStorage(); + uint32_t denseLen = uint32_t(stack.getDenseInitializedLength()); + fprintf(stderr, " denseInitializedLength: %u\n,", denseLen); + uint32_t len = stack.length(); + fprintf(stderr, " length: %u\n,", len); + fprintf(stderr, " data: [\n"); + const Value* elements = getDenseElements(); + for (uint32_t i = 0; i < std::max(len, denseLen); i++) { + fprintf(stderr, " [%u]: ", i); + js::DumpValue(elements[i]); + } + fprintf(stderr, " ],\n"); + fprintf(stderr, " }),\n"); + } else { + fprintf(stderr, " stackStorage: None\n"); + } + if (isSuspended()) { + fprintf(stderr, " resumeIndex: Some(%u),\n", resumeIndex()); + } else { + fprintf(stderr, " resumeIndex: None, /* (not suspended) */\n"); + } + fprintf(stderr, "}\n"); +} +#endif + +void AbstractGeneratorObject::finalSuspend(HandleObject obj) { + auto* genObj = &obj->as<AbstractGeneratorObject>(); + MOZ_ASSERT(genObj->isRunning()); + genObj->setClosed(); +} + +static AbstractGeneratorObject* GetGeneratorObjectForCall(JSContext* cx, + CallObject& callObj) { + // The ".generator" binding is always present and always "aliased". + mozilla::Maybe<PropertyInfo> prop = + callObj.lookup(cx, cx->names().dotGenerator); + if (prop.isNothing()) { + return nullptr; + } + Value genValue = callObj.getSlot(prop->slot()); + + // If the `Generator; SetAliasedVar ".generator"; InitialYield` bytecode + // sequence has not run yet, genValue is undefined. + return genValue.isObject() + ? &genValue.toObject().as<AbstractGeneratorObject>() + : nullptr; +} + +AbstractGeneratorObject* js::GetGeneratorObjectForFrame( + JSContext* cx, AbstractFramePtr frame) { + cx->check(frame); + MOZ_ASSERT(frame.isGeneratorFrame()); + + if (frame.isModuleFrame()) { + ModuleEnvironmentObject* moduleEnv = + frame.script()->module()->environment(); + mozilla::Maybe<PropertyInfo> prop = + moduleEnv->lookup(cx, cx->names().dotGenerator); + Value genValue = moduleEnv->getSlot(prop->slot()); + return genValue.isObject() + ? &genValue.toObject().as<AbstractGeneratorObject>() + : nullptr; + } + if (!frame.hasInitialEnvironment()) { + return nullptr; + } + + return GetGeneratorObjectForCall(cx, frame.callObj()); +} + +AbstractGeneratorObject* js::GetGeneratorObjectForEnvironment( + JSContext* cx, HandleObject env) { + auto* call = CallObject::find(env); + return call ? GetGeneratorObjectForCall(cx, *call) : nullptr; +} + +bool js::GeneratorThrowOrReturn(JSContext* cx, AbstractFramePtr frame, + Handle<AbstractGeneratorObject*> genObj, + HandleValue arg, + GeneratorResumeKind resumeKind) { + MOZ_ASSERT(genObj->isRunning()); + if (resumeKind == GeneratorResumeKind::Throw) { + cx->setPendingException(arg, ShouldCaptureStack::Maybe); + } else { + MOZ_ASSERT(resumeKind == GeneratorResumeKind::Return); + + MOZ_ASSERT_IF(genObj->is<GeneratorObject>(), arg.isObject()); + frame.setReturnValue(arg); + + RootedValue closing(cx, MagicValue(JS_GENERATOR_CLOSING)); + cx->setPendingException(closing, nullptr); + } + return false; +} + +bool AbstractGeneratorObject::resume(JSContext* cx, + InterpreterActivation& activation, + Handle<AbstractGeneratorObject*> genObj, + HandleValue arg, HandleValue resumeKind) { + MOZ_ASSERT(genObj->isSuspended()); + + RootedFunction callee(cx, &genObj->callee()); + RootedObject envChain(cx, &genObj->environmentChain()); + if (!activation.resumeGeneratorFrame(callee, envChain)) { + return false; + } + activation.regs().fp()->setResumedGenerator(); + + if (genObj->hasArgsObj()) { + activation.regs().fp()->initArgsObj(genObj->argsObj()); + } + + if (genObj->hasStackStorage() && !genObj->isStackStorageEmpty()) { + JSScript* script = activation.regs().fp()->script(); + ArrayObject* storage = &genObj->stackStorage(); + uint32_t len = storage->getDenseInitializedLength(); + activation.regs().fp()->restoreGeneratorSlots(storage); + activation.regs().sp += len - script->nfixed(); + storage->setDenseInitializedLength(0); + } + + JSScript* script = callee->nonLazyScript(); + uint32_t offset = script->resumeOffsets()[genObj->resumeIndex()]; + activation.regs().pc = script->offsetToPC(offset); + + // Push arg, generator, resumeKind Values on the generator's stack. + activation.regs().sp += 3; + MOZ_ASSERT(activation.regs().spForStackDepth(activation.regs().stackDepth())); + activation.regs().sp[-3] = arg; + activation.regs().sp[-2] = ObjectValue(*genObj); + activation.regs().sp[-1] = resumeKind; + + genObj->setRunning(); + return true; +} + +GeneratorObject* GeneratorObject::create(JSContext* cx, HandleFunction fun) { + MOZ_ASSERT(fun->isGenerator() && !fun->isAsync()); + + // FIXME: This would be faster if we could avoid doing a lookup to get + // the prototype for the instance. Bug 906600. + RootedValue pval(cx); + if (!GetProperty(cx, fun, fun, cx->names().prototype, &pval)) { + return nullptr; + } + RootedObject proto(cx, pval.isObject() ? &pval.toObject() : nullptr); + if (!proto) { + proto = GlobalObject::getOrCreateGeneratorObjectPrototype(cx, cx->global()); + if (!proto) { + return nullptr; + } + } + return NewObjectWithGivenProto<GeneratorObject>(cx, proto); +} + +const JSClass GeneratorObject::class_ = { + "Generator", + JSCLASS_HAS_RESERVED_SLOTS(GeneratorObject::RESERVED_SLOTS), + &classOps_, +}; + +const JSClassOps GeneratorObject::classOps_ = { + nullptr, // addProperty + nullptr, // delProperty + nullptr, // enumerate + nullptr, // newEnumerate + nullptr, // resolve + nullptr, // mayResolve + nullptr, // finalize + nullptr, // call + nullptr, // construct + CallTraceMethod<AbstractGeneratorObject>, // trace +}; + +static const JSFunctionSpec generator_methods[] = { + JS_SELF_HOSTED_FN("next", "GeneratorNext", 1, 0), + JS_SELF_HOSTED_FN("throw", "GeneratorThrow", 1, 0), + JS_SELF_HOSTED_FN("return", "GeneratorReturn", 1, 0), JS_FS_END}; + +JSObject* js::NewTenuredObjectWithFunctionPrototype( + JSContext* cx, Handle<GlobalObject*> global) { + RootedObject proto(cx, &cx->global()->getFunctionPrototype()); + return NewPlainObjectWithProto(cx, proto, TenuredObject); +} + +static JSObject* CreateGeneratorFunction(JSContext* cx, JSProtoKey key) { + RootedObject proto(cx, &cx->global()->getFunctionConstructor()); + Handle<PropertyName*> name = cx->names().GeneratorFunction; + return NewFunctionWithProto(cx, Generator, 1, FunctionFlags::NATIVE_CTOR, + nullptr, name, proto, gc::AllocKind::FUNCTION, + TenuredObject); +} + +static JSObject* CreateGeneratorFunctionPrototype(JSContext* cx, + JSProtoKey key) { + return NewTenuredObjectWithFunctionPrototype(cx, cx->global()); +} + +static bool GeneratorFunctionClassFinish(JSContext* cx, + HandleObject genFunction, + HandleObject genFunctionProto) { + Handle<GlobalObject*> global = cx->global(); + + // Change the "constructor" property to non-writable before adding any other + // properties, so it's still the last property and can be modified without a + // dictionary-mode transition. + MOZ_ASSERT(genFunctionProto->as<NativeObject>().getLastProperty().key() == + NameToId(cx->names().constructor)); + MOZ_ASSERT(!genFunctionProto->as<NativeObject>().inDictionaryMode()); + + RootedValue genFunctionVal(cx, ObjectValue(*genFunction)); + if (!DefineDataProperty(cx, genFunctionProto, cx->names().constructor, + genFunctionVal, JSPROP_READONLY)) { + return false; + } + MOZ_ASSERT(!genFunctionProto->as<NativeObject>().inDictionaryMode()); + + RootedObject iteratorProto( + cx, GlobalObject::getOrCreateIteratorPrototype(cx, global)); + if (!iteratorProto) { + return false; + } + + RootedObject genObjectProto(cx, GlobalObject::createBlankPrototypeInheriting( + cx, &PlainObject::class_, iteratorProto)); + if (!genObjectProto) { + return false; + } + if (!DefinePropertiesAndFunctions(cx, genObjectProto, nullptr, + generator_methods) || + !DefineToStringTag(cx, genObjectProto, cx->names().Generator)) { + return false; + } + + if (!LinkConstructorAndPrototype(cx, genFunctionProto, genObjectProto, + JSPROP_READONLY, JSPROP_READONLY) || + !DefineToStringTag(cx, genFunctionProto, cx->names().GeneratorFunction)) { + return false; + } + + global->setGeneratorObjectPrototype(genObjectProto); + + return true; +} + +static const ClassSpec GeneratorFunctionClassSpec = { + CreateGeneratorFunction, + CreateGeneratorFunctionPrototype, + nullptr, + nullptr, + nullptr, + nullptr, + GeneratorFunctionClassFinish, + ClassSpec::DontDefineConstructor}; + +const JSClass js::GeneratorFunctionClass = { + "GeneratorFunction", 0, JS_NULL_CLASS_OPS, &GeneratorFunctionClassSpec}; + +const Value& AbstractGeneratorObject::getUnaliasedLocal(uint32_t slot) const { + MOZ_ASSERT(isSuspended()); + MOZ_ASSERT(hasStackStorage()); + MOZ_ASSERT(slot < callee().nonLazyScript()->nfixed()); + return stackStorage().getDenseElement(slot); +} + +void AbstractGeneratorObject::setUnaliasedLocal(uint32_t slot, + const Value& value) { + MOZ_ASSERT(isSuspended()); + MOZ_ASSERT(hasStackStorage()); + MOZ_ASSERT(slot < callee().nonLazyScript()->nfixed()); + return stackStorage().setDenseElement(slot, value); +} + +bool AbstractGeneratorObject::isAfterYield() { + return isAfterYieldOrAwait(JSOp::Yield); +} + +bool AbstractGeneratorObject::isAfterAwait() { + return isAfterYieldOrAwait(JSOp::Await); +} + +bool AbstractGeneratorObject::isAfterYieldOrAwait(JSOp op) { + if (isClosed() || isRunning()) { + return false; + } + + JSScript* script = callee().nonLazyScript(); + jsbytecode* code = script->code(); + uint32_t nextOffset = script->resumeOffsets()[resumeIndex()]; + if (JSOp(code[nextOffset]) != JSOp::AfterYield) { + return false; + } + + static_assert(JSOpLength_Yield == JSOpLength_InitialYield, + "JSOp::Yield and JSOp::InitialYield must have the same length"); + static_assert(JSOpLength_Yield == JSOpLength_Await, + "JSOp::Yield and JSOp::Await must have the same length"); + + uint32_t offset = nextOffset - JSOpLength_Yield; + JSOp prevOp = JSOp(code[offset]); + MOZ_ASSERT(prevOp == JSOp::InitialYield || prevOp == JSOp::Yield || + prevOp == JSOp::Await); + + return prevOp == op; +} + +template <> +bool JSObject::is<js::AbstractGeneratorObject>() const { + return is<GeneratorObject>() || is<AsyncFunctionGeneratorObject>() || + is<AsyncGeneratorObject>(); +} + +GeneratorResumeKind js::ParserAtomToResumeKind( + frontend::TaggedParserAtomIndex atom) { + if (atom == frontend::TaggedParserAtomIndex::WellKnown::next()) { + return GeneratorResumeKind::Next; + } + if (atom == frontend::TaggedParserAtomIndex::WellKnown::throw_()) { + return GeneratorResumeKind::Throw; + } + MOZ_ASSERT(atom == frontend::TaggedParserAtomIndex::WellKnown::return_()); + return GeneratorResumeKind::Return; +} + +JSAtom* js::ResumeKindToAtom(JSContext* cx, GeneratorResumeKind kind) { + switch (kind) { + case GeneratorResumeKind::Next: + return cx->names().next; + + case GeneratorResumeKind::Throw: + return cx->names().throw_; + + case GeneratorResumeKind::Return: + return cx->names().return_; + } + MOZ_CRASH("Invalid resume kind"); +} |