/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: * 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/. */ /* * JS parser. * * This is a recursive-descent parser for the JavaScript language specified by * "The ECMAScript Language Specification" (Standard ECMA-262). It uses * lexical and semantic feedback to disambiguate non-LL(1) structures. It * generates trees of nodes induced by the recursive parsing (not precise * syntax trees, see Parser.h). After tree construction, it rewrites trees to * fold constants and evaluate compile-time expressions. * * This parser attempts no error recovery. */ #include "frontend/Parser.h" #include #include "jsapi.h" #include "jsatom.h" #include "jscntxt.h" #include "jsfun.h" #include "jsopcode.h" #include "jsscript.h" #include "jstypes.h" #include "builtin/ModuleObject.h" #include "builtin/SelfHostingDefines.h" #include "frontend/BytecodeCompiler.h" #include "frontend/FoldConstants.h" #include "frontend/TokenStream.h" #include "wasm/AsmJS.h" #include "jsatominlines.h" #include "jsscriptinlines.h" #include "frontend/ParseNode-inl.h" #include "vm/EnvironmentObject-inl.h" using namespace js; using namespace js::gc; using mozilla::Maybe; using mozilla::Move; using mozilla::Nothing; using mozilla::PodCopy; using mozilla::PodZero; using mozilla::Some; using JS::AutoGCRooter; namespace js { namespace frontend { using DeclaredNamePtr = ParseContext::Scope::DeclaredNamePtr; using AddDeclaredNamePtr = ParseContext::Scope::AddDeclaredNamePtr; using BindingIter = ParseContext::Scope::BindingIter; using UsedNamePtr = UsedNameTracker::UsedNameMap::Ptr; /* Read a token. Report an error and return null() if that token isn't of type tt. */ #define MUST_MATCH_TOKEN_MOD(tt, modifier, errorNumber) \ JS_BEGIN_MACRO \ TokenKind token; \ if (!tokenStream.getToken(&token, modifier)) \ return null(); \ if (token != tt) { \ error(errorNumber); \ return null(); \ } \ JS_END_MACRO #define MUST_MATCH_TOKEN(tt, errno) MUST_MATCH_TOKEN_MOD(tt, TokenStream::None, errno) template static inline void PropagateTransitiveParseFlags(const T* inner, U* outer) { if (inner->bindingsAccessedDynamically()) outer->setBindingsAccessedDynamically(); if (inner->hasDebuggerStatement()) outer->setHasDebuggerStatement(); if (inner->hasDirectEval()) outer->setHasDirectEval(); } static const char* DeclarationKindString(DeclarationKind kind) { switch (kind) { case DeclarationKind::PositionalFormalParameter: case DeclarationKind::FormalParameter: return "formal parameter"; case DeclarationKind::CoverArrowParameter: return "cover arrow parameter"; case DeclarationKind::Var: return "var"; case DeclarationKind::Let: return "let"; case DeclarationKind::Const: return "const"; case DeclarationKind::Import: return "import"; case DeclarationKind::BodyLevelFunction: case DeclarationKind::LexicalFunction: return "function"; case DeclarationKind::VarForAnnexBLexicalFunction: return "annex b var"; case DeclarationKind::ForOfVar: return "var in for-of"; case DeclarationKind::SimpleCatchParameter: case DeclarationKind::CatchParameter: return "catch parameter"; } MOZ_CRASH("Bad DeclarationKind"); } static bool StatementKindIsBraced(StatementKind kind) { return kind == StatementKind::Block || kind == StatementKind::Switch || kind == StatementKind::Try || kind == StatementKind::Catch || kind == StatementKind::Finally; } void ParseContext::Scope::dump(ParseContext* pc) { ExclusiveContext* cx = pc->sc()->context; fprintf(stdout, "ParseScope %p", this); fprintf(stdout, "\n decls:\n"); for (DeclaredNameMap::Range r = declared_->all(); !r.empty(); r.popFront()) { JSAutoByteString bytes; if (!AtomToPrintableString(cx, r.front().key(), &bytes)) return; DeclaredNameInfo& info = r.front().value().wrapped; fprintf(stdout, " %s %s%s\n", DeclarationKindString(info.kind()), bytes.ptr(), info.closedOver() ? " (closed over)" : ""); } fprintf(stdout, "\n"); } /* static */ void ParseContext::Scope::removeVarForAnnexBLexicalFunction(ParseContext* pc, JSAtom* name) { // Local strict mode is allowed, e.g., a class binding removing a // synthesized Annex B binding. MOZ_ASSERT(!pc->sc()->strictScript); for (ParseContext::Scope* scope = pc->innermostScope(); scope != pc->varScope().enclosing(); scope = scope->enclosing()) { if (DeclaredNamePtr p = scope->declared_->lookup(name)) { if (p->value()->kind() == DeclarationKind::VarForAnnexBLexicalFunction) scope->declared_->remove(p); } } // Annex B semantics no longer applies to any functions with this name, as // an early error would have occurred. pc->removeInnerFunctionBoxesForAnnexB(name); } static bool DeclarationKindIsCatchParameter(DeclarationKind kind) { return kind == DeclarationKind::SimpleCatchParameter || kind == DeclarationKind::CatchParameter; } bool ParseContext::Scope::addCatchParameters(ParseContext* pc, Scope& catchParamScope) { if (pc->useAsmOrInsideUseAsm()) return true; for (DeclaredNameMap::Range r = catchParamScope.declared_->all(); !r.empty(); r.popFront()) { DeclarationKind kind = r.front().value()->kind(); MOZ_ASSERT(DeclarationKindIsCatchParameter(kind)); JSAtom* name = r.front().key(); AddDeclaredNamePtr p = lookupDeclaredNameForAdd(name); MOZ_ASSERT(!p); if (!addDeclaredName(pc, p, name, kind)) return false; } return true; } void ParseContext::Scope::removeCatchParameters(ParseContext* pc, Scope& catchParamScope) { if (pc->useAsmOrInsideUseAsm()) return; for (DeclaredNameMap::Range r = catchParamScope.declared_->all(); !r.empty(); r.popFront()) { DeclaredNamePtr p = declared_->lookup(r.front().key()); MOZ_ASSERT(p); // This check is needed because the catch body could have declared // vars, which would have been added to catchParamScope. if (DeclarationKindIsCatchParameter(r.front().value()->kind())) declared_->remove(p); } } void SharedContext::computeAllowSyntax(Scope* scope) { for (ScopeIter si(scope); si; si++) { if (si.kind() == ScopeKind::Function) { JSFunction* fun = si.scope()->as().canonicalFunction(); if (fun->isArrow()) continue; allowNewTarget_ = true; allowSuperProperty_ = fun->allowSuperProperty(); allowSuperCall_ = fun->isDerivedClassConstructor(); return; } } } void SharedContext::computeThisBinding(Scope* scope) { for (ScopeIter si(scope); si; si++) { if (si.kind() == ScopeKind::Module) { thisBinding_ = ThisBinding::Module; return; } if (si.kind() == ScopeKind::Function) { JSFunction* fun = si.scope()->as().canonicalFunction(); // Arrow functions and generator expression lambdas don't have // their own `this` binding. if (fun->isArrow() || fun->nonLazyScript()->isGeneratorExp()) continue; // Derived class constructors (including nested arrow functions and // eval) need TDZ checks when accessing |this|. if (fun->isDerivedClassConstructor()) needsThisTDZChecks_ = true; thisBinding_ = ThisBinding::Function; return; } } thisBinding_ = ThisBinding::Global; } void SharedContext::computeInWith(Scope* scope) { for (ScopeIter si(scope); si; si++) { if (si.kind() == ScopeKind::With) { inWith_ = true; break; } } } EvalSharedContext::EvalSharedContext(ExclusiveContext* cx, JSObject* enclosingEnv, Scope* enclosingScope, Directives directives, bool extraWarnings) : SharedContext(cx, Kind::Eval, directives, extraWarnings), enclosingScope_(cx, enclosingScope), bindings(cx) { computeAllowSyntax(enclosingScope); computeInWith(enclosingScope); computeThisBinding(enclosingScope); // Like all things Debugger, Debugger.Frame.eval needs special // handling. Since the environment chain of such evals are non-syntactic // (DebuggerEnvironmentProxy is not an EnvironmentObject), computing the // this binding with respect to enclosingScope is incorrect if the // Debugger.Frame is a function frame. Recompute the this binding if we // are such an eval. if (enclosingEnv && enclosingScope->hasOnChain(ScopeKind::NonSyntactic)) { // For Debugger.Frame.eval with bindings, the environment chain may // have more than the DebugEnvironmentProxy. JSObject* env = enclosingEnv; while (env) { if (env->is()) env = &env->as().environment(); if (env->is()) { computeThisBinding(env->as().callee().nonLazyScript()->bodyScope()); break; } env = env->enclosingEnvironment(); } } } bool ParseContext::init() { if (scriptId_ == UINT32_MAX) { tokenStream_.reportError(JSMSG_NEED_DIET, js_script_str); return false; } ExclusiveContext* cx = sc()->context; if (isFunctionBox()) { // Named lambdas always need a binding for their own name. If this // binding is closed over when we finish parsing the function in // finishExtraFunctionScopes, the function box needs to be marked as // needing a dynamic DeclEnv object. RootedFunction fun(cx, functionBox()->function()); if (fun->isNamedLambda()) { if (!namedLambdaScope_->init(this)) return false; AddDeclaredNamePtr p = namedLambdaScope_->lookupDeclaredNameForAdd(fun->explicitName()); MOZ_ASSERT(!p); if (!namedLambdaScope_->addDeclaredName(this, p, fun->explicitName(), DeclarationKind::Const)) { return false; } } if (!functionScope_->init(this)) return false; if (!positionalFormalParameterNames_.acquire(cx)) return false; } if (!closedOverBindingsForLazy_.acquire(cx)) return false; if (!sc()->strict()) { if (!innerFunctionBoxesForAnnexB_.acquire(cx)) return false; } return true; } bool ParseContext::addInnerFunctionBoxForAnnexB(FunctionBox* funbox) { for (uint32_t i = 0; i < innerFunctionBoxesForAnnexB_->length(); i++) { if (!innerFunctionBoxesForAnnexB_[i]) { innerFunctionBoxesForAnnexB_[i] = funbox; return true; } } return innerFunctionBoxesForAnnexB_->append(funbox); } void ParseContext::removeInnerFunctionBoxesForAnnexB(JSAtom* name) { for (uint32_t i = 0; i < innerFunctionBoxesForAnnexB_->length(); i++) { if (FunctionBox* funbox = innerFunctionBoxesForAnnexB_[i]) { if (funbox->function()->explicitName() == name) innerFunctionBoxesForAnnexB_[i] = nullptr; } } } void ParseContext::finishInnerFunctionBoxesForAnnexB() { // Strict mode doesn't have wack Annex B function semantics. Or we // could've failed to initialize ParseContext. if (sc()->strict() || !innerFunctionBoxesForAnnexB_) return; for (uint32_t i = 0; i < innerFunctionBoxesForAnnexB_->length(); i++) { if (FunctionBox* funbox = innerFunctionBoxesForAnnexB_[i]) funbox->isAnnexB = true; } } ParseContext::~ParseContext() { // Any funboxes still in the list at the end of parsing means no early // error would have occurred for declaring a binding in the nearest var // scope. Mark them as needing extra assignments to this var binding. finishInnerFunctionBoxesForAnnexB(); } bool UsedNameTracker::noteUse(ExclusiveContext* cx, JSAtom* name, uint32_t scriptId, uint32_t scopeId) { if (UsedNameMap::AddPtr p = map_.lookupForAdd(name)) { if (!p->value().noteUsedInScope(scriptId, scopeId)) return false; } else { UsedNameInfo info(cx); if (!info.noteUsedInScope(scriptId, scopeId)) return false; if (!map_.add(p, name, Move(info))) return false; } return true; } void UsedNameTracker::UsedNameInfo::resetToScope(uint32_t scriptId, uint32_t scopeId) { while (!uses_.empty()) { Use& innermost = uses_.back(); if (innermost.scopeId < scopeId) break; MOZ_ASSERT(innermost.scriptId >= scriptId); uses_.popBack(); } } void UsedNameTracker::rewind(RewindToken token) { scriptCounter_ = token.scriptId; scopeCounter_ = token.scopeId; for (UsedNameMap::Range r = map_.all(); !r.empty(); r.popFront()) r.front().value().resetToScope(token.scriptId, token.scopeId); } FunctionBox::FunctionBox(ExclusiveContext* cx, LifoAlloc& alloc, ObjectBox* traceListHead, JSFunction* fun, uint32_t preludeStart, Directives directives, bool extraWarnings, GeneratorKind generatorKind, FunctionAsyncKind asyncKind) : ObjectBox(fun, traceListHead), SharedContext(cx, Kind::ObjectBox, directives, extraWarnings), enclosingScope_(nullptr), namedLambdaBindings_(nullptr), functionScopeBindings_(nullptr), extraVarScopeBindings_(nullptr), functionNode(nullptr), bufStart(0), bufEnd(0), startLine(1), startColumn(0), preludeStart(preludeStart), length(0), generatorKindBits_(GeneratorKindAsBits(generatorKind)), asyncKindBits_(AsyncKindAsBits(asyncKind)), isGenexpLambda(false), hasDestructuringArgs(false), hasParameterExprs(false), hasDirectEvalInParameterExpr(false), hasDuplicateParameters(false), useAsm(false), insideUseAsm(false), isAnnexB(false), wasEmitted(false), declaredArguments(false), usesArguments(false), usesApply(false), usesThis(false), usesReturn(false), hasRest_(false), funCxFlags() { // Functions created at parse time may be set singleton after parsing and // baked into JIT code, so they must be allocated tenured. They are held by // the JSScript so cannot be collected during a minor GC anyway. MOZ_ASSERT(fun->isTenured()); } void FunctionBox::initFromLazyFunction() { JSFunction* fun = function(); if (fun->lazyScript()->isDerivedClassConstructor()) setDerivedClassConstructor(); if (fun->lazyScript()->needsHomeObject()) setNeedsHomeObject(); enclosingScope_ = fun->lazyScript()->enclosingScope(); initWithEnclosingScope(enclosingScope_); } void FunctionBox::initStandaloneFunction(Scope* enclosingScope) { // Standalone functions are Function or Generator constructors and are // always scoped to the global. MOZ_ASSERT(enclosingScope->is()); enclosingScope_ = enclosingScope; allowNewTarget_ = true; thisBinding_ = ThisBinding::Function; } void FunctionBox::initWithEnclosingParseContext(ParseContext* enclosing, FunctionSyntaxKind kind) { SharedContext* sc = enclosing->sc(); useAsm = sc->isFunctionBox() && sc->asFunctionBox()->useAsmOrInsideUseAsm(); JSFunction* fun = function(); // Arrow functions and generator expression lambdas don't have // their own `this` binding. if (fun->isArrow()) { allowNewTarget_ = sc->allowNewTarget(); allowSuperProperty_ = sc->allowSuperProperty(); allowSuperCall_ = sc->allowSuperCall(); needsThisTDZChecks_ = sc->needsThisTDZChecks(); thisBinding_ = sc->thisBinding(); } else { allowNewTarget_ = true; allowSuperProperty_ = fun->allowSuperProperty(); if (kind == DerivedClassConstructor) { setDerivedClassConstructor(); allowSuperCall_ = true; needsThisTDZChecks_ = true; } if (isGenexpLambda) thisBinding_ = sc->thisBinding(); else thisBinding_ = ThisBinding::Function; } if (sc->inWith()) { inWith_ = true; } else { auto isWith = [](ParseContext::Statement* stmt) { return stmt->kind() == StatementKind::With; }; inWith_ = enclosing->findInnermostStatement(isWith); } } void FunctionBox::initWithEnclosingScope(Scope* enclosingScope) { if (!function()->isArrow()) { allowNewTarget_ = true; allowSuperProperty_ = function()->allowSuperProperty(); if (isDerivedClassConstructor()) { setDerivedClassConstructor(); allowSuperCall_ = true; needsThisTDZChecks_ = true; } thisBinding_ = ThisBinding::Function; } else { computeAllowSyntax(enclosingScope); computeThisBinding(enclosingScope); } computeInWith(enclosingScope); } template void Parser::error(unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); #ifdef DEBUG bool result = #endif tokenStream.reportCompileErrorNumberVA(pos().begin, JSREPORT_ERROR, errorNumber, args); MOZ_ASSERT(!result, "reporting an error returned true?"); va_end(args); } template void Parser::errorAt(uint32_t offset, unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); #ifdef DEBUG bool result = #endif tokenStream.reportCompileErrorNumberVA(offset, JSREPORT_ERROR, errorNumber, args); MOZ_ASSERT(!result, "reporting an error returned true?"); va_end(args); } template bool Parser::warning(unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); bool result = tokenStream.reportCompileErrorNumberVA(pos().begin, JSREPORT_WARNING, errorNumber, args); va_end(args); return result; } template bool Parser::warningAt(uint32_t offset, unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); bool result = tokenStream.reportCompileErrorNumberVA(offset, JSREPORT_WARNING, errorNumber, args); va_end(args); return result; } template bool Parser::extraWarning(unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); bool result = tokenStream.reportExtraWarningErrorNumberVA(pos().begin, errorNumber, args); va_end(args); return result; } template bool Parser::strictModeError(unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); bool res = tokenStream.reportStrictModeErrorNumberVA(pos().begin, pc->sc()->strict(), errorNumber, args); va_end(args); return res; } template bool Parser::strictModeErrorAt(uint32_t offset, unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); bool res = tokenStream.reportStrictModeErrorNumberVA(offset, pc->sc()->strict(), errorNumber, args); va_end(args); return res; } template bool Parser::reportNoOffset(ParseReportKind kind, bool strict, unsigned errorNumber, ...) { va_list args; va_start(args, errorNumber); bool result = false; uint32_t offset = TokenStream::NoOffset; switch (kind) { case ParseError: result = tokenStream.reportCompileErrorNumberVA(offset, JSREPORT_ERROR, errorNumber, args); break; case ParseWarning: result = tokenStream.reportCompileErrorNumberVA(offset, JSREPORT_WARNING, errorNumber, args); break; case ParseExtraWarning: result = tokenStream.reportExtraWarningErrorNumberVA(offset, errorNumber, args); break; case ParseStrictError: result = tokenStream.reportStrictModeErrorNumberVA(offset, strict, errorNumber, args); break; } va_end(args); return result; } template <> bool Parser::abortIfSyntaxParser() { handler.disableSyntaxParser(); return true; } template <> bool Parser::abortIfSyntaxParser() { abortedSyntaxParse = true; return false; } template Parser::Parser(ExclusiveContext* cx, LifoAlloc& alloc, const ReadOnlyCompileOptions& options, const char16_t* chars, size_t length, bool foldConstants, UsedNameTracker& usedNames, Parser* syntaxParser, LazyScript* lazyOuterFunction) : AutoGCRooter(cx, PARSER), context(cx), alloc(alloc), tokenStream(cx, options, chars, length, thisForCtor()), traceListHead(nullptr), pc(nullptr), usedNames(usedNames), sct(nullptr), ss(nullptr), keepAtoms(cx->perThreadData), foldConstants(foldConstants), #ifdef DEBUG checkOptionsCalled(false), #endif abortedSyntaxParse(false), isUnexpectedEOF_(false), handler(cx, alloc, tokenStream, syntaxParser, lazyOuterFunction) { cx->perThreadData->frontendCollectionPool.addActiveCompilation(); // The Mozilla specific JSOPTION_EXTRA_WARNINGS option adds extra warnings // which are not generated if functions are parsed lazily. Note that the // standard "use strict" does not inhibit lazy parsing. if (options.extraWarningsOption) handler.disableSyntaxParser(); tempPoolMark = alloc.mark(); } template bool Parser::checkOptions() { #ifdef DEBUG checkOptionsCalled = true; #endif if (!tokenStream.checkOptions()) return false; return true; } template Parser::~Parser() { MOZ_ASSERT(checkOptionsCalled); alloc.release(tempPoolMark); /* * The parser can allocate enormous amounts of memory for large functions. * Eagerly free the memory now (which otherwise won't be freed until the * next GC) to avoid unnecessary OOMs. */ alloc.freeAllIfHugeAndUnused(); context->perThreadData->frontendCollectionPool.removeActiveCompilation(); } template ObjectBox* Parser::newObjectBox(JSObject* obj) { MOZ_ASSERT(obj); /* * We use JSContext.tempLifoAlloc to allocate parsed objects and place them * on a list in this Parser to ensure GC safety. Thus the tempLifoAlloc * arenas containing the entries must be alive until we are done with * scanning, parsing and code generation for the whole script or top-level * function. */ ObjectBox* objbox = alloc.new_(obj, traceListHead); if (!objbox) { ReportOutOfMemory(context); return nullptr; } traceListHead = objbox; return objbox; } template FunctionBox* Parser::newFunctionBox(Node fn, JSFunction* fun, uint32_t preludeStart, Directives inheritedDirectives, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB) { MOZ_ASSERT(fun); MOZ_ASSERT_IF(tryAnnexB, !pc->sc()->strict()); /* * We use JSContext.tempLifoAlloc to allocate parsed objects and place them * on a list in this Parser to ensure GC safety. Thus the tempLifoAlloc * arenas containing the entries must be alive until we are done with * scanning, parsing and code generation for the whole script or top-level * function. */ FunctionBox* funbox = alloc.new_(context, alloc, traceListHead, fun, preludeStart, inheritedDirectives, options().extraWarningsOption, generatorKind, asyncKind); if (!funbox) { ReportOutOfMemory(context); return nullptr; } traceListHead = funbox; if (fn) handler.setFunctionBox(fn, funbox); if (tryAnnexB && !pc->addInnerFunctionBoxForAnnexB(funbox)) return nullptr; return funbox; } ModuleSharedContext::ModuleSharedContext(ExclusiveContext* cx, ModuleObject* module, Scope* enclosingScope, ModuleBuilder& builder) : SharedContext(cx, Kind::Module, Directives(true), false), module_(cx, module), enclosingScope_(cx, enclosingScope), bindings(cx), builder(builder) { thisBinding_ = ThisBinding::Module; } template void Parser::trace(JSTracer* trc) { ObjectBox::TraceList(trc, traceListHead); } void MarkParser(JSTracer* trc, AutoGCRooter* parser) { static_cast*>(parser)->trace(trc); } /* * Parse a top-level JS script. */ template typename ParseHandler::Node Parser::parse() { MOZ_ASSERT(checkOptionsCalled); Directives directives(options().strictOption); GlobalSharedContext globalsc(context, ScopeKind::Global, directives, options().extraWarningsOption); ParseContext globalpc(this, &globalsc, /* newDirectives = */ nullptr); if (!globalpc.init()) return null(); ParseContext::VarScope varScope(this); if (!varScope.init(pc)) return null(); Node pn = statementList(YieldIsName); if (!pn) return null(); TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (tt != TOK_EOF) { error(JSMSG_GARBAGE_AFTER_INPUT, "script", TokenKindToDesc(tt)); return null(); } if (foldConstants) { if (!FoldConstants(context, &pn, this)) return null(); } return pn; } /* * Strict mode forbids introducing new definitions for 'eval', 'arguments', or * for any strict mode reserved keyword. */ template bool Parser::isValidStrictBinding(PropertyName* name) { return name != context->names().eval && name != context->names().arguments && name != context->names().let && name != context->names().static_ && !(IsKeyword(name) && name != context->names().await); } /* * Check that it is permitted to introduce a binding for |name|. Use |pos| for * reporting error locations. */ template bool Parser::checkStrictBinding(PropertyName* name, TokenPos pos) { if (!pc->sc()->needStrictChecks()) return true; if (!isValidStrictBinding(name)) { JSAutoByteString bytes; if (!AtomToPrintableString(context, name, &bytes)) return false; return strictModeErrorAt(pos.begin, JSMSG_BAD_BINDING, bytes.ptr()); } return true; } /* * Returns true if all parameter names are valid strict mode binding names and * no duplicate parameter names are present. */ template bool Parser::hasValidSimpleStrictParameterNames() { MOZ_ASSERT(pc->isFunctionBox() && pc->functionBox()->hasSimpleParameterList()); if (pc->functionBox()->hasDuplicateParameters) return false; for (size_t i = 0; i < pc->positionalFormalParameterNames().length(); i++) { JSAtom* name = pc->positionalFormalParameterNames()[i]; MOZ_ASSERT(name); if (!isValidStrictBinding(name->asPropertyName())) return false; } return true; } template void Parser::reportRedeclaration(HandlePropertyName name, DeclarationKind kind, TokenPos pos) { JSAutoByteString bytes; if (!AtomToPrintableString(context, name, &bytes)) return; errorAt(pos.begin, JSMSG_REDECLARED_VAR, DeclarationKindString(kind), bytes.ptr()); } // notePositionalFormalParameter is called for both the arguments of a regular // function definition and the arguments specified by the Function // constructor. // // The 'disallowDuplicateParams' bool indicates whether the use of another // feature (destructuring or default arguments) disables duplicate arguments. // (ECMA-262 requires us to support duplicate parameter names, but, for newer // features, we consider the code to have "opted in" to higher standards and // forbid duplicates.) template bool Parser::notePositionalFormalParameter(Node fn, HandlePropertyName name, bool disallowDuplicateParams, bool* duplicatedParam) { if (AddDeclaredNamePtr p = pc->functionScope().lookupDeclaredNameForAdd(name)) { if (disallowDuplicateParams) { error(JSMSG_BAD_DUP_ARGS); return false; } // Strict-mode disallows duplicate args. We may not know whether we are // in strict mode or not (since the function body hasn't been parsed). // In such cases, report will queue up the potential error and return // 'true'. if (pc->sc()->needStrictChecks()) { JSAutoByteString bytes; if (!AtomToPrintableString(context, name, &bytes)) return false; if (!strictModeError(JSMSG_DUPLICATE_FORMAL, bytes.ptr())) return false; } *duplicatedParam = true; } else { DeclarationKind kind = DeclarationKind::PositionalFormalParameter; if (!pc->functionScope().addDeclaredName(pc, p, name, kind)) return false; } if (!pc->positionalFormalParameterNames().append(name)) { ReportOutOfMemory(context); return false; } Node paramNode = newName(name); if (!paramNode) return false; if (!checkStrictBinding(name, pos())) return false; handler.addFunctionFormalParameter(fn, paramNode); return true; } template bool Parser::noteDestructuredPositionalFormalParameter(Node fn, Node destruct) { // Append an empty name to the positional formals vector to keep track of // argument slots when making FunctionScope::Data. if (!pc->positionalFormalParameterNames().append(nullptr)) { ReportOutOfMemory(context); return false; } handler.addFunctionFormalParameter(fn, destruct); return true; } static bool DeclarationKindIsVar(DeclarationKind kind) { return kind == DeclarationKind::Var || kind == DeclarationKind::BodyLevelFunction || kind == DeclarationKind::VarForAnnexBLexicalFunction || kind == DeclarationKind::ForOfVar; } template Maybe Parser::isVarRedeclaredInEval(HandlePropertyName name, DeclarationKind kind) { MOZ_ASSERT(DeclarationKindIsVar(kind)); MOZ_ASSERT(pc->sc()->isEvalContext()); // In the case of eval, we also need to check enclosing VM scopes to see // if the var declaration is allowed in the context. // // This check is necessary in addition to // js::CheckEvalDeclarationConflicts because we only know during parsing // if a var is bound by for-of. Scope* enclosingScope = pc->sc()->compilationEnclosingScope(); Scope* varScope = EvalScope::nearestVarScopeForDirectEval(enclosingScope); MOZ_ASSERT(varScope); for (ScopeIter si(enclosingScope); si; si++) { for (js::BindingIter bi(si.scope()); bi; bi++) { if (bi.name() != name) continue; switch (bi.kind()) { case BindingKind::Let: { // Annex B.3.5 allows redeclaring simple (non-destructured) // catch parameters with var declarations, except when it // appears in a for-of. bool annexB35Allowance = si.kind() == ScopeKind::SimpleCatch && kind != DeclarationKind::ForOfVar; if (!annexB35Allowance) { return Some(ScopeKindIsCatch(si.kind()) ? DeclarationKind::CatchParameter : DeclarationKind::Let); } break; } case BindingKind::Const: return Some(DeclarationKind::Const); case BindingKind::Import: case BindingKind::FormalParameter: case BindingKind::Var: case BindingKind::NamedLambdaCallee: break; } } if (si.scope() == varScope) break; } return Nothing(); } static bool DeclarationKindIsParameter(DeclarationKind kind) { return kind == DeclarationKind::PositionalFormalParameter || kind == DeclarationKind::FormalParameter; } template bool Parser::tryDeclareVar(HandlePropertyName name, DeclarationKind kind, Maybe* redeclaredKind) { MOZ_ASSERT(DeclarationKindIsVar(kind)); // It is an early error if a 'var' declaration appears inside a // scope contour that has a lexical declaration of the same name. For // example, the following are early errors: // // { let x; var x; } // { { var x; } let x; } // // And the following are not: // // { var x; var x; } // { { let x; } var x; } for (ParseContext::Scope* scope = pc->innermostScope(); scope != pc->varScope().enclosing(); scope = scope->enclosing()) { if (AddDeclaredNamePtr p = scope->lookupDeclaredNameForAdd(name)) { DeclarationKind declaredKind = p->value()->kind(); if (DeclarationKindIsVar(declaredKind)) { // Any vars that are redeclared as body-level functions must // be recorded as body-level functions. // // In the case of global and eval scripts, GlobalDeclaration- // Instantiation [1] and EvalDeclarationInstantiation [2] // check for the declarability of global var and function // bindings via CanDeclareVar [3] and CanDeclareGlobal- // Function [4]. CanDeclareGlobalFunction is strictly more // restrictive than CanDeclareGlobalVar, so record the more // restrictive kind. These semantics are implemented in // CheckCanDeclareGlobalBinding. // // For a var previously declared as ForOfVar, this previous // DeclarationKind is used only to check for if the // 'arguments' binding should be declared. Since body-level // functions shadow 'arguments' [5], it is correct to alter // the kind to BodyLevelFunction. See // declareFunctionArgumentsObject. // // For a var previously declared as // VarForAnnexBLexicalFunction, this previous DeclarationKind // is used so that vars synthesized solely for Annex B.3.3 may // be removed if an early error would occur. If a synthesized // Annex B.3.3 var has the same name as a body-level function, // this is not a redeclaration, and indeed, because the // body-level function binds the name, this name should not be // removed should a redeclaration occur in the future. Thus it // is also correct to alter the kind to BodyLevelFunction. // // [1] ES 15.1.11 // [2] ES 18.2.1.3 // [3] ES 8.1.1.4.15 // [4] ES 8.1.1.4.16 // [5] ES 9.2.12 if (kind == DeclarationKind::BodyLevelFunction) p->value()->alterKind(kind); } else if (!DeclarationKindIsParameter(declaredKind)) { // Annex B.3.5 allows redeclaring simple (non-destructured) // catch parameters with var declarations, except when it // appears in a for-of. bool annexB35Allowance = declaredKind == DeclarationKind::SimpleCatchParameter && kind != DeclarationKind::ForOfVar; // Annex B.3.3 allows redeclaring functions in the same block. bool annexB33Allowance = declaredKind == DeclarationKind::LexicalFunction && kind == DeclarationKind::VarForAnnexBLexicalFunction && scope == pc->innermostScope(); if (!annexB35Allowance && !annexB33Allowance) { *redeclaredKind = Some(declaredKind); return true; } } } else { if (!scope->addDeclaredName(pc, p, name, kind)) return false; } } if (!pc->sc()->strict() && pc->sc()->isEvalContext()) *redeclaredKind = isVarRedeclaredInEval(name, kind); return true; } template bool Parser::tryDeclareVarForAnnexBLexicalFunction(HandlePropertyName name, bool* tryAnnexB) { Maybe redeclaredKind; if (!tryDeclareVar(name, DeclarationKind::VarForAnnexBLexicalFunction, &redeclaredKind)) return false; if (redeclaredKind) { // If an early error would have occurred, undo all the // VarForAnnexBLexicalFunction declarations. *tryAnnexB = false; ParseContext::Scope::removeVarForAnnexBLexicalFunction(pc, name); } else { *tryAnnexB = true; } return true; } template bool Parser::checkLexicalDeclarationDirectlyWithinBlock(ParseContext::Statement& stmt, DeclarationKind kind, TokenPos pos) { MOZ_ASSERT(DeclarationKindIsLexical(kind)); // It is an early error to declare a lexical binding not directly // within a block. if (!StatementKindIsBraced(stmt.kind()) && stmt.kind() != StatementKind::ForLoopLexicalHead) { errorAt(pos.begin, stmt.kind() == StatementKind::Label ? JSMSG_LEXICAL_DECL_LABEL : JSMSG_LEXICAL_DECL_NOT_IN_BLOCK, DeclarationKindString(kind)); return false; } return true; } template bool Parser::noteDeclaredName(HandlePropertyName name, DeclarationKind kind, TokenPos pos) { // The asm.js validator does all its own symbol-table management so, as an // optimization, avoid doing any work here. if (pc->useAsmOrInsideUseAsm()) return true; if (!checkStrictBinding(name, pos)) return false; switch (kind) { case DeclarationKind::Var: case DeclarationKind::BodyLevelFunction: case DeclarationKind::ForOfVar: { Maybe redeclaredKind; if (!tryDeclareVar(name, kind, &redeclaredKind)) return false; if (redeclaredKind) { reportRedeclaration(name, *redeclaredKind, pos); return false; } break; } case DeclarationKind::FormalParameter: { // It is an early error if any non-positional formal parameter name // (e.g., destructuring formal parameter) is duplicated. AddDeclaredNamePtr p = pc->functionScope().lookupDeclaredNameForAdd(name); if (p) { error(JSMSG_BAD_DUP_ARGS); return false; } if (!pc->functionScope().addDeclaredName(pc, p, name, kind)) return false; break; } case DeclarationKind::LexicalFunction: { // Functions in block have complex allowances in sloppy mode for being // labelled that other lexical declarations do not have. Those checks // are more complex than calling checkLexicalDeclarationDirectlyWithin- // Block and are done inline in callers. ParseContext::Scope* scope = pc->innermostScope(); if (AddDeclaredNamePtr p = scope->lookupDeclaredNameForAdd(name)) { // It is usually an early error if there is another declaration // with the same name in the same scope. // // In sloppy mode, lexical functions may redeclare other lexical // functions for web compatibility reasons. if (pc->sc()->strict() || (p->value()->kind() != DeclarationKind::LexicalFunction && p->value()->kind() != DeclarationKind::VarForAnnexBLexicalFunction)) { reportRedeclaration(name, p->value()->kind(), pos); return false; } // Update the DeclarationKind to make a LexicalFunction // declaration that shadows the VarForAnnexBLexicalFunction. p->value()->alterKind(kind); } else { if (!scope->addDeclaredName(pc, p, name, kind)) return false; } break; } case DeclarationKind::Let: case DeclarationKind::Const: // The BoundNames of LexicalDeclaration and ForDeclaration must not // contain 'let'. (CatchParameter is the only lexical binding form // without this restriction.) if (name == context->names().let) { errorAt(pos.begin, JSMSG_LEXICAL_DECL_DEFINES_LET); return false; } MOZ_FALLTHROUGH; case DeclarationKind::Import: // Module code is always strict, so 'let' is always a keyword and never a name. MOZ_ASSERT(name != context->names().let); MOZ_FALLTHROUGH; case DeclarationKind::SimpleCatchParameter: case DeclarationKind::CatchParameter: { if (ParseContext::Statement* stmt = pc->innermostStatement()) { if (!checkLexicalDeclarationDirectlyWithinBlock(*stmt, kind, pos)) return false; } ParseContext::Scope* scope = pc->innermostScope(); // For body-level lexically declared names in a function, it is an // early error if there is a formal parameter of the same name. This // needs a special check if there is an extra var scope due to // parameter expressions. if (pc->isFunctionExtraBodyVarScopeInnermost()) { DeclaredNamePtr p = pc->functionScope().lookupDeclaredName(name); if (p && DeclarationKindIsParameter(p->value()->kind())) { reportRedeclaration(name, p->value()->kind(), pos); return false; } } // It is an early error if there is another declaration with the same // name in the same scope. AddDeclaredNamePtr p = scope->lookupDeclaredNameForAdd(name); if (p) { // If the early error would have occurred due to Annex B.3.3 // semantics, remove the synthesized Annex B var declaration, do // not report the redeclaration, and declare the lexical name. if (p->value()->kind() == DeclarationKind::VarForAnnexBLexicalFunction) { ParseContext::Scope::removeVarForAnnexBLexicalFunction(pc, name); p = scope->lookupDeclaredNameForAdd(name); MOZ_ASSERT(!p); } else { reportRedeclaration(name, p->value()->kind(), pos); return false; } } if (!p && !scope->addDeclaredName(pc, p, name, kind)) return false; break; } case DeclarationKind::CoverArrowParameter: // CoverArrowParameter is only used as a placeholder declaration kind. break; case DeclarationKind::PositionalFormalParameter: MOZ_CRASH("Positional formal parameter names should use " "notePositionalFormalParameter"); break; case DeclarationKind::VarForAnnexBLexicalFunction: MOZ_CRASH("Synthesized Annex B vars should go through " "tryDeclareVarForAnnexBLexicalFunction"); break; } return true; } template bool Parser::noteUsedName(HandlePropertyName name) { // If the we are delazifying, the LazyScript already has all the // closed-over info for bindings and there's no need to track used names. if (handler.canSkipLazyClosedOverBindings()) return true; // The asm.js validator does all its own symbol-table management so, as an // optimization, avoid doing any work here. if (pc->useAsmOrInsideUseAsm()) return true; // Global bindings are properties and not actual bindings; we don't need // to know if they are closed over. So no need to track used name at the // global scope. It is not incorrect to track them, this is an // optimization. ParseContext::Scope* scope = pc->innermostScope(); if (pc->sc()->isGlobalContext() && scope == &pc->varScope()) return true; return usedNames.noteUse(context, name, pc->scriptId(), scope->id()); } template bool Parser::hasUsedName(HandlePropertyName name) { if (UsedNamePtr p = usedNames.lookup(name)) return p->value().isUsedInScript(pc->scriptId()); return false; } template bool Parser::propagateFreeNamesAndMarkClosedOverBindings(ParseContext::Scope& scope) { if (handler.canSkipLazyClosedOverBindings()) { // Scopes are nullptr-delimited in the LazyScript closed over bindings // array. while (JSAtom* name = handler.nextLazyClosedOverBinding()) scope.lookupDeclaredName(name)->value()->setClosedOver(); return true; } bool isSyntaxParser = mozilla::IsSame::value; uint32_t scriptId = pc->scriptId(); uint32_t scopeId = scope.id(); for (BindingIter bi = scope.bindings(pc); bi; bi++) { if (UsedNamePtr p = usedNames.lookup(bi.name())) { bool closedOver; p->value().noteBoundInScope(scriptId, scopeId, &closedOver); if (closedOver) { bi.setClosedOver(); if (isSyntaxParser && !pc->closedOverBindingsForLazy().append(bi.name())) { ReportOutOfMemory(context); return false; } } } } // Append a nullptr to denote end-of-scope. if (isSyntaxParser && !pc->closedOverBindingsForLazy().append(nullptr)) { ReportOutOfMemory(context); return false; } return true; } template <> bool Parser::checkStatementsEOF() { // This is designed to be paired with parsing a statement list at the top // level. // // The statementList() call breaks on TOK_RC, so make sure we've // reached EOF here. TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return false; if (tt != TOK_EOF) { error(JSMSG_UNEXPECTED_TOKEN, "expression", TokenKindToDesc(tt)); return false; } return true; } template static typename Scope::Data* NewEmptyBindingData(ExclusiveContext* cx, LifoAlloc& alloc, uint32_t numBindings) { using Data = typename Scope::Data; size_t allocSize = Scope::sizeOfData(numBindings); auto* bindings = alloc.allocInSize(allocSize, numBindings); if (!bindings) ReportOutOfMemory(cx); return bindings; } /** * Copy-construct |BindingName|s from |bindings| into |cursor|, then return * the location one past the newly-constructed |BindingName|s. */ static MOZ_MUST_USE BindingName* FreshlyInitializeBindings(BindingName* cursor, const Vector& bindings) { for (const BindingName& binding : bindings) new (cursor++) BindingName(binding); return cursor; } template <> Maybe Parser::newGlobalScopeData(ParseContext::Scope& scope) { Vector funs(context); Vector vars(context); Vector lets(context); Vector consts(context); bool allBindingsClosedOver = pc->sc()->allBindingsClosedOver(); for (BindingIter bi = scope.bindings(pc); bi; bi++) { BindingName binding(bi.name(), allBindingsClosedOver || bi.closedOver()); switch (bi.kind()) { case BindingKind::Var: if (bi.declarationKind() == DeclarationKind::BodyLevelFunction) { if (!funs.append(binding)) return Nothing(); } else { if (!vars.append(binding)) return Nothing(); } break; case BindingKind::Let: if (!lets.append(binding)) return Nothing(); break; case BindingKind::Const: if (!consts.append(binding)) return Nothing(); break; default: MOZ_CRASH("Bad global scope BindingKind"); } } GlobalScope::Data* bindings = nullptr; uint32_t numBindings = funs.length() + vars.length() + lets.length() + consts.length(); if (numBindings > 0) { bindings = NewEmptyBindingData(context, alloc, numBindings); if (!bindings) return Nothing(); // The ordering here is important. See comments in GlobalScope. BindingName* start = bindings->trailingNames.start(); BindingName* cursor = start; cursor = FreshlyInitializeBindings(cursor, funs); bindings->varStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, vars); bindings->letStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, lets); bindings->constStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, consts); bindings->length = numBindings; } return Some(bindings); } template <> Maybe Parser::newModuleScopeData(ParseContext::Scope& scope) { Vector imports(context); Vector vars(context); Vector lets(context); Vector consts(context); bool allBindingsClosedOver = pc->sc()->allBindingsClosedOver(); for (BindingIter bi = scope.bindings(pc); bi; bi++) { // Imports are indirect bindings and must not be given known slots. BindingName binding(bi.name(), (allBindingsClosedOver || bi.closedOver()) && bi.kind() != BindingKind::Import); switch (bi.kind()) { case BindingKind::Import: if (!imports.append(binding)) return Nothing(); break; case BindingKind::Var: if (!vars.append(binding)) return Nothing(); break; case BindingKind::Let: if (!lets.append(binding)) return Nothing(); break; case BindingKind::Const: if (!consts.append(binding)) return Nothing(); break; default: MOZ_CRASH("Bad module scope BindingKind"); } } ModuleScope::Data* bindings = nullptr; uint32_t numBindings = imports.length() + vars.length() + lets.length() + consts.length(); if (numBindings > 0) { bindings = NewEmptyBindingData(context, alloc, numBindings); if (!bindings) return Nothing(); // The ordering here is important. See comments in ModuleScope. BindingName* start = bindings->trailingNames.start(); BindingName* cursor = start; cursor = FreshlyInitializeBindings(cursor, imports); bindings->varStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, vars); bindings->letStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, lets); bindings->constStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, consts); bindings->length = numBindings; } return Some(bindings); } template <> Maybe Parser::newEvalScopeData(ParseContext::Scope& scope) { Vector funs(context); Vector vars(context); for (BindingIter bi = scope.bindings(pc); bi; bi++) { // Eval scopes only contain 'var' bindings. Make all bindings aliased // for now. MOZ_ASSERT(bi.kind() == BindingKind::Var); BindingName binding(bi.name(), true); if (bi.declarationKind() == DeclarationKind::BodyLevelFunction) { if (!funs.append(binding)) return Nothing(); } else { if (!vars.append(binding)) return Nothing(); } } EvalScope::Data* bindings = nullptr; uint32_t numBindings = funs.length() + vars.length(); if (numBindings > 0) { bindings = NewEmptyBindingData(context, alloc, numBindings); if (!bindings) return Nothing(); BindingName* start = bindings->trailingNames.start(); BindingName* cursor = start; // Keep track of what vars are functions. This is only used in BCE to omit // superfluous DEFVARs. cursor = FreshlyInitializeBindings(cursor, funs); bindings->varStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, vars); bindings->length = numBindings; } return Some(bindings); } template <> Maybe Parser::newFunctionScopeData(ParseContext::Scope& scope, bool hasParameterExprs) { Vector positionalFormals(context); Vector formals(context); Vector vars(context); bool allBindingsClosedOver = pc->sc()->allBindingsClosedOver(); bool hasDuplicateParams = pc->functionBox()->hasDuplicateParameters; // Positional parameter names must be added in order of appearance as they are // referenced using argument slots. for (size_t i = 0; i < pc->positionalFormalParameterNames().length(); i++) { JSAtom* name = pc->positionalFormalParameterNames()[i]; BindingName bindName; if (name) { DeclaredNamePtr p = scope.lookupDeclaredName(name); // Do not consider any positional formal parameters closed over if // there are parameter defaults. It is the binding in the defaults // scope that is closed over instead. bool closedOver = allBindingsClosedOver || (p && p->value()->closedOver()); // If the parameter name has duplicates, only the final parameter // name should be on the environment, as otherwise the environment // object would have multiple, same-named properties. if (hasDuplicateParams) { for (size_t j = pc->positionalFormalParameterNames().length() - 1; j > i; j--) { if (pc->positionalFormalParameterNames()[j] == name) { closedOver = false; break; } } } bindName = BindingName(name, closedOver); } if (!positionalFormals.append(bindName)) return Nothing(); } for (BindingIter bi = scope.bindings(pc); bi; bi++) { BindingName binding(bi.name(), allBindingsClosedOver || bi.closedOver()); switch (bi.kind()) { case BindingKind::FormalParameter: // Positional parameter names are already handled above. if (bi.declarationKind() == DeclarationKind::FormalParameter) { if (!formals.append(binding)) return Nothing(); } break; case BindingKind::Var: // The only vars in the function scope when there are parameter // exprs, which induces a separate var environment, should be the // special internal bindings. MOZ_ASSERT_IF(hasParameterExprs, bi.name() == context->names().arguments || bi.name() == context->names().dotThis || bi.name() == context->names().dotGenerator); if (!vars.append(binding)) return Nothing(); break; default: break; } } FunctionScope::Data* bindings = nullptr; uint32_t numBindings = positionalFormals.length() + formals.length() + vars.length(); if (numBindings > 0) { bindings = NewEmptyBindingData(context, alloc, numBindings); if (!bindings) return Nothing(); // The ordering here is important. See comments in FunctionScope. BindingName* start = bindings->trailingNames.start(); BindingName* cursor = start; cursor = FreshlyInitializeBindings(cursor, positionalFormals); bindings->nonPositionalFormalStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, formals); bindings->varStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, vars); bindings->length = numBindings; } return Some(bindings); } template <> Maybe Parser::newVarScopeData(ParseContext::Scope& scope) { Vector vars(context); bool allBindingsClosedOver = pc->sc()->allBindingsClosedOver(); for (BindingIter bi = scope.bindings(pc); bi; bi++) { BindingName binding(bi.name(), allBindingsClosedOver || bi.closedOver()); if (!vars.append(binding)) return Nothing(); } VarScope::Data* bindings = nullptr; uint32_t numBindings = vars.length(); if (numBindings > 0) { bindings = NewEmptyBindingData(context, alloc, numBindings); if (!bindings) return Nothing(); // The ordering here is important. See comments in FunctionScope. BindingName* start = bindings->trailingNames.start(); BindingName* cursor = start; cursor = FreshlyInitializeBindings(cursor, vars); bindings->length = numBindings; } return Some(bindings); } template <> Maybe Parser::newLexicalScopeData(ParseContext::Scope& scope) { Vector lets(context); Vector consts(context); // Unlike other scopes with bindings which are body-level, it is unknown // if pc->sc()->allBindingsClosedOver() is correct at the time of // finishing parsing a lexical scope. // // Instead, pc->sc()->allBindingsClosedOver() is checked in // EmitterScope::enterLexical. Also see comment there. for (BindingIter bi = scope.bindings(pc); bi; bi++) { BindingName binding(bi.name(), bi.closedOver()); switch (bi.kind()) { case BindingKind::Let: if (!lets.append(binding)) return Nothing(); break; case BindingKind::Const: if (!consts.append(binding)) return Nothing(); break; default: break; } } LexicalScope::Data* bindings = nullptr; uint32_t numBindings = lets.length() + consts.length(); if (numBindings > 0) { bindings = NewEmptyBindingData(context, alloc, numBindings); if (!bindings) return Nothing(); // The ordering here is important. See comments in LexicalScope. BindingName* cursor = bindings->trailingNames.start(); BindingName* start = cursor; cursor = FreshlyInitializeBindings(cursor, lets); bindings->constStart = cursor - start; cursor = FreshlyInitializeBindings(cursor, consts); bindings->length = numBindings; } return Some(bindings); } template <> SyntaxParseHandler::Node Parser::finishLexicalScope(ParseContext::Scope& scope, Node body) { if (!propagateFreeNamesAndMarkClosedOverBindings(scope)) return null(); return body; } template <> ParseNode* Parser::finishLexicalScope(ParseContext::Scope& scope, ParseNode* body) { if (!propagateFreeNamesAndMarkClosedOverBindings(scope)) return nullptr; Maybe bindings = newLexicalScopeData(scope); if (!bindings) return nullptr; return handler.newLexicalScope(*bindings, body); } static bool IsArgumentsUsedInLegacyGenerator(ExclusiveContext* cx, Scope* scope) { JSAtom* argumentsName = cx->names().arguments; for (ScopeIter si(scope); si; si++) { if (si.scope()->is()) { // Using a shadowed lexical 'arguments' is okay. for (::BindingIter bi(si.scope()); bi; bi++) { if (bi.name() == argumentsName) return false; } } else if (si.scope()->is()) { // It's an error to use 'arguments' in a legacy generator expression. JSScript* script = si.scope()->as().script(); return script->isGeneratorExp() && script->isLegacyGenerator(); } } return false; } template <> ParseNode* Parser::evalBody(EvalSharedContext* evalsc) { ParseContext evalpc(this, evalsc, /* newDirectives = */ nullptr); if (!evalpc.init()) return nullptr; ParseContext::VarScope varScope(this); if (!varScope.init(pc)) return nullptr; // All evals have an implicit non-extensible lexical scope. ParseContext::Scope lexicalScope(this); if (!lexicalScope.init(pc)) return nullptr; ParseNode* body = statementList(YieldIsName); if (!body) return nullptr; if (!checkStatementsEOF()) return nullptr; body = finishLexicalScope(lexicalScope, body); if (!body) return nullptr; // It's an error to use 'arguments' in a legacy generator expression. // // If 'arguments' appears free (i.e. not a declared name) or if the // declaration does not shadow the enclosing script's 'arguments' // binding (i.e. not a lexical declaration), check the enclosing // script. if (hasUsedName(context->names().arguments)) { if (IsArgumentsUsedInLegacyGenerator(context, pc->sc()->compilationEnclosingScope())) { error(JSMSG_BAD_GENEXP_BODY, js_arguments_str); return nullptr; } } #ifdef DEBUG if (evalpc.superScopeNeedsHomeObject() && evalsc->compilationEnclosingScope()) { // If superScopeNeedsHomeObject_ is set and we are an entry-point // ParseContext, then we must be emitting an eval script, and the // outer function must already be marked as needing a home object // since it contains an eval. ScopeIter si(evalsc->compilationEnclosingScope()); for (; si; si++) { if (si.kind() == ScopeKind::Function) { JSFunction* fun = si.scope()->as().canonicalFunction(); if (fun->isArrow()) continue; MOZ_ASSERT(fun->allowSuperProperty()); MOZ_ASSERT(fun->nonLazyScript()->needsHomeObject()); break; } } MOZ_ASSERT(!si.done(), "Eval must have found an enclosing function box scope that allows super.property"); } #endif if (!FoldConstants(context, &body, this)) return nullptr; Maybe bindings = newEvalScopeData(pc->varScope()); if (!bindings) return nullptr; evalsc->bindings = *bindings; return body; } template <> ParseNode* Parser::globalBody(GlobalSharedContext* globalsc) { ParseContext globalpc(this, globalsc, /* newDirectives = */ nullptr); if (!globalpc.init()) return nullptr; ParseContext::VarScope varScope(this); if (!varScope.init(pc)) return nullptr; ParseNode* body = statementList(YieldIsName); if (!body) return nullptr; if (!checkStatementsEOF()) return nullptr; if (!FoldConstants(context, &body, this)) return nullptr; Maybe bindings = newGlobalScopeData(pc->varScope()); if (!bindings) return nullptr; globalsc->bindings = *bindings; return body; } template <> ParseNode* Parser::moduleBody(ModuleSharedContext* modulesc) { MOZ_ASSERT(checkOptionsCalled); ParseContext modulepc(this, modulesc, nullptr); if (!modulepc.init()) return null(); ParseContext::VarScope varScope(this); if (!varScope.init(pc)) return nullptr; Node mn = handler.newModule(); if (!mn) return null(); AutoAwaitIsKeyword awaitIsKeyword(&tokenStream, true); ParseNode* pn = statementList(YieldIsKeyword); if (!pn) return null(); MOZ_ASSERT(pn->isKind(PNK_STATEMENTLIST)); mn->pn_body = pn; TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (tt != TOK_EOF) { error(JSMSG_GARBAGE_AFTER_INPUT, "module", TokenKindToDesc(tt)); return null(); } if (!modulesc->builder.buildTables()) return null(); // Check exported local bindings exist and mark them as closed over. for (auto entry : modulesc->builder.localExportEntries()) { JSAtom* name = entry->localName(); MOZ_ASSERT(name); DeclaredNamePtr p = modulepc.varScope().lookupDeclaredName(name); if (!p) { JSAutoByteString str; if (!str.encodeLatin1(context, name)) return null(); JS_ReportErrorNumberLatin1(context->asJSContext(), GetErrorMessage, nullptr, JSMSG_MISSING_EXPORT, str.ptr()); return null(); } p->value()->setClosedOver(); } if (!FoldConstants(context, &pn, this)) return null(); if (!propagateFreeNamesAndMarkClosedOverBindings(modulepc.varScope())) return null(); Maybe bindings = newModuleScopeData(modulepc.varScope()); if (!bindings) return nullptr; modulesc->bindings = *bindings; return mn; } template <> SyntaxParseHandler::Node Parser::moduleBody(ModuleSharedContext* modulesc) { MOZ_ALWAYS_FALSE(abortIfSyntaxParser()); return SyntaxParseHandler::NodeFailure; } template bool Parser::hasUsedFunctionSpecialName(HandlePropertyName name) { MOZ_ASSERT(name == context->names().arguments || name == context->names().dotThis); return hasUsedName(name) || pc->functionBox()->bindingsAccessedDynamically(); } template bool Parser::declareFunctionThis() { // The asm.js validator does all its own symbol-table management so, as an // optimization, avoid doing any work here. if (pc->useAsmOrInsideUseAsm()) return true; // Derived class constructors emit JSOP_CHECKRETURN, which requires // '.this' to be bound. FunctionBox* funbox = pc->functionBox(); HandlePropertyName dotThis = context->names().dotThis; bool declareThis; if (handler.canSkipLazyClosedOverBindings()) declareThis = funbox->function()->lazyScript()->hasThisBinding(); else declareThis = hasUsedFunctionSpecialName(dotThis) || funbox->isDerivedClassConstructor(); if (declareThis) { ParseContext::Scope& funScope = pc->functionScope(); AddDeclaredNamePtr p = funScope.lookupDeclaredNameForAdd(dotThis); MOZ_ASSERT(!p); if (!funScope.addDeclaredName(pc, p, dotThis, DeclarationKind::Var)) return false; funbox->setHasThisBinding(); } return true; } template typename ParseHandler::Node Parser::newInternalDotName(HandlePropertyName name) { Node nameNode = newName(name); if (!nameNode) return null(); if (!noteUsedName(name)) return null(); return nameNode; } template typename ParseHandler::Node Parser::newThisName() { return newInternalDotName(context->names().dotThis); } template typename ParseHandler::Node Parser::newDotGeneratorName() { return newInternalDotName(context->names().dotGenerator); } template bool Parser::declareDotGeneratorName() { // The special '.generator' binding must be on the function scope, as // generators expect to find it on the CallObject. ParseContext::Scope& funScope = pc->functionScope(); HandlePropertyName dotGenerator = context->names().dotGenerator; AddDeclaredNamePtr p = funScope.lookupDeclaredNameForAdd(dotGenerator); if (!p && !funScope.addDeclaredName(pc, p, dotGenerator, DeclarationKind::Var)) return false; return true; } template bool Parser::finishFunctionScopes() { FunctionBox* funbox = pc->functionBox(); if (funbox->hasParameterExprs) { if (!propagateFreeNamesAndMarkClosedOverBindings(pc->functionScope())) return false; } if (funbox->function()->isNamedLambda()) { if (!propagateFreeNamesAndMarkClosedOverBindings(pc->namedLambdaScope())) return false; } return true; } template <> bool Parser::finishFunction() { if (!finishFunctionScopes()) return false; FunctionBox* funbox = pc->functionBox(); bool hasParameterExprs = funbox->hasParameterExprs; if (hasParameterExprs) { Maybe bindings = newVarScopeData(pc->varScope()); if (!bindings) return false; funbox->extraVarScopeBindings().set(*bindings); } { Maybe bindings = newFunctionScopeData(pc->functionScope(), hasParameterExprs); if (!bindings) return false; funbox->functionScopeBindings().set(*bindings); } if (funbox->function()->isNamedLambda()) { Maybe bindings = newLexicalScopeData(pc->namedLambdaScope()); if (!bindings) return false; funbox->namedLambdaBindings().set(*bindings); } return true; } template <> bool Parser::finishFunction() { // The LazyScript for a lazily parsed function needs to know its set of // free variables and inner functions so that when it is fully parsed, we // can skip over any already syntax parsed inner functions and still // retain correct scope information. if (!finishFunctionScopes()) return false; // There are too many bindings or inner functions to be saved into the // LazyScript. Do a full parse. if (pc->closedOverBindingsForLazy().length() >= LazyScript::NumClosedOverBindingsLimit || pc->innerFunctionsForLazy.length() >= LazyScript::NumInnerFunctionsLimit) { MOZ_ALWAYS_FALSE(abortIfSyntaxParser()); return false; } FunctionBox* funbox = pc->functionBox(); RootedFunction fun(context, funbox->function()); LazyScript* lazy = LazyScript::Create(context, fun, pc->closedOverBindingsForLazy(), pc->innerFunctionsForLazy, versionNumber(), funbox->bufStart, funbox->bufEnd, funbox->preludeStart, funbox->startLine, funbox->startColumn); if (!lazy) return false; // Flags that need to be copied into the JSScript when we do the full // parse. if (pc->sc()->strict()) lazy->setStrict(); lazy->setGeneratorKind(funbox->generatorKind()); lazy->setAsyncKind(funbox->asyncKind()); if (funbox->hasRest()) lazy->setHasRest(); if (funbox->isLikelyConstructorWrapper()) lazy->setLikelyConstructorWrapper(); if (funbox->isDerivedClassConstructor()) lazy->setIsDerivedClassConstructor(); if (funbox->needsHomeObject()) lazy->setNeedsHomeObject(); if (funbox->declaredArguments) lazy->setShouldDeclareArguments(); if (funbox->hasThisBinding()) lazy->setHasThisBinding(); // Flags that need to copied back into the parser when we do the full // parse. PropagateTransitiveParseFlags(funbox, lazy); fun->initLazyScript(lazy); return true; } static YieldHandling GetYieldHandling(GeneratorKind generatorKind, FunctionAsyncKind asyncKind) { if (asyncKind == AsyncFunction) return YieldIsName; if (generatorKind == NotGenerator) return YieldIsName; return YieldIsKeyword; } template <> ParseNode* Parser::standaloneFunction(HandleFunction fun, HandleScope enclosingScope, Maybe parameterListEnd, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, Directives inheritedDirectives, Directives* newDirectives) { MOZ_ASSERT(checkOptionsCalled); // Skip prelude. TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); if (asyncKind == AsyncFunction) { MOZ_ASSERT(tt == TOK_ASYNC); if (!tokenStream.getToken(&tt)) return null(); } MOZ_ASSERT(tt == TOK_FUNCTION); if (!tokenStream.getToken(&tt)) return null(); if (generatorKind == StarGenerator && asyncKind == SyncFunction) { MOZ_ASSERT(tt == TOK_MUL); if (!tokenStream.getToken(&tt)) return null(); } // Skip function name, if present. if (tt == TOK_NAME || tt == TOK_YIELD) { MOZ_ASSERT(tokenStream.currentName() == fun->explicitName()); } else { MOZ_ASSERT(fun->explicitName() == nullptr); tokenStream.ungetToken(); } Node fn = handler.newFunctionStatement(); if (!fn) return null(); ParseNode* argsbody = handler.newList(PNK_PARAMSBODY); if (!argsbody) return null(); fn->pn_body = argsbody; FunctionBox* funbox = newFunctionBox(fn, fun, /* preludeStart = */ 0, inheritedDirectives, generatorKind, asyncKind, /* tryAnnexB = */ false); if (!funbox) return null(); funbox->initStandaloneFunction(enclosingScope); ParseContext funpc(this, funbox, newDirectives); if (!funpc.init()) return null(); funpc.setIsStandaloneFunctionBody(); YieldHandling yieldHandling = GetYieldHandling(generatorKind, asyncKind); AutoAwaitIsKeyword awaitIsKeyword(&tokenStream, asyncKind == AsyncFunction); if (!functionFormalParametersAndBody(InAllowed, yieldHandling, fn, Statement, parameterListEnd)) { return null(); } if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (tt != TOK_EOF) { error(JSMSG_GARBAGE_AFTER_INPUT, "function body", TokenKindToDesc(tt)); return null(); } if (!FoldConstants(context, &fn, this)) return null(); return fn; } template bool Parser::declareFunctionArgumentsObject() { FunctionBox* funbox = pc->functionBox(); ParseContext::Scope& funScope = pc->functionScope(); ParseContext::Scope& varScope = pc->varScope(); bool hasExtraBodyVarScope = &funScope != &varScope; // Time to implement the odd semantics of 'arguments'. HandlePropertyName argumentsName = context->names().arguments; bool tryDeclareArguments; if (handler.canSkipLazyClosedOverBindings()) tryDeclareArguments = funbox->function()->lazyScript()->shouldDeclareArguments(); else tryDeclareArguments = hasUsedFunctionSpecialName(argumentsName); // ES 9.2.12 steps 19 and 20 say formal parameters, lexical bindings, // and body-level functions named 'arguments' shadow the arguments // object. // // So even if there wasn't a free use of 'arguments' but there is a var // binding of 'arguments', we still might need the arguments object. // // If we have an extra var scope due to parameter expressions and the body // declared 'var arguments', we still need to declare 'arguments' in the // function scope. DeclaredNamePtr p = varScope.lookupDeclaredName(argumentsName); if (p && (p->value()->kind() == DeclarationKind::Var || p->value()->kind() == DeclarationKind::ForOfVar)) { if (hasExtraBodyVarScope) tryDeclareArguments = true; else funbox->usesArguments = true; } if (tryDeclareArguments) { AddDeclaredNamePtr p = funScope.lookupDeclaredNameForAdd(argumentsName); if (!p) { if (!funScope.addDeclaredName(pc, p, argumentsName, DeclarationKind::Var)) return false; funbox->declaredArguments = true; funbox->usesArguments = true; } else if (hasExtraBodyVarScope) { // Formal parameters shadow the arguments object. return true; } } // Compute if we need an arguments object. if (funbox->usesArguments) { // There is an 'arguments' binding. Is the arguments object definitely // needed? // // Also see the flags' comments in ContextFlags. funbox->setArgumentsHasLocalBinding(); // Dynamic scope access destroys all hope of optimization. if (pc->sc()->bindingsAccessedDynamically()) funbox->setDefinitelyNeedsArgsObj(); // If a script contains the debugger statement either directly or // within an inner function, the arguments object should be created // eagerly so the Debugger API may observe bindings. if (pc->sc()->hasDebuggerStatement()) funbox->setDefinitelyNeedsArgsObj(); } return true; } template typename ParseHandler::Node Parser::functionBody(InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, FunctionBodyType type) { MOZ_ASSERT(pc->isFunctionBox()); MOZ_ASSERT(!pc->funHasReturnExpr && !pc->funHasReturnVoid); #ifdef DEBUG uint32_t startYieldOffset = pc->lastYieldOffset; #endif Node pn; if (type == StatementListBody) { bool inheritedStrict = pc->sc()->strict(); pn = statementList(yieldHandling); if (!pn) return null(); // When we transitioned from non-strict to strict mode, we need to // validate that all parameter names are valid strict mode names. if (!inheritedStrict && pc->sc()->strict()) { MOZ_ASSERT(pc->sc()->hasExplicitUseStrict(), "strict mode should only change when a 'use strict' directive is present"); if (!hasValidSimpleStrictParameterNames()) { // Request that this function be reparsed as strict to report // the invalid parameter name at the correct source location. pc->newDirectives->setStrict(); return null(); } } } else { MOZ_ASSERT(type == ExpressionBody); // Async functions are implemented as star generators, and star // generators are assumed to be statement lists, to prepend initial // `yield`. Node stmtList = null(); if (pc->isAsync()) { stmtList = handler.newStatementList(pos()); if (!stmtList) return null(); } Node kid = assignExpr(inHandling, yieldHandling, TripledotProhibited); if (!kid) return null(); pn = handler.newReturnStatement(kid, handler.getPosition(kid)); if (!pn) return null(); if (pc->isAsync()) { handler.addStatementToList(stmtList, pn); pn = stmtList; } } switch (pc->generatorKind()) { case NotGenerator: MOZ_ASSERT(pc->lastYieldOffset == startYieldOffset); break; case LegacyGenerator: MOZ_ASSERT(pc->lastYieldOffset != startYieldOffset); // These should throw while parsing the yield expression. MOZ_ASSERT(kind != Arrow); MOZ_ASSERT(!IsGetterKind(kind)); MOZ_ASSERT(!IsSetterKind(kind)); MOZ_ASSERT(!IsConstructorKind(kind)); MOZ_ASSERT(kind != Method); MOZ_ASSERT(type != ExpressionBody); break; case StarGenerator: MOZ_ASSERT_IF(!pc->isAsync(), kind != Arrow); MOZ_ASSERT_IF(!pc->isAsync(), type == StatementListBody); break; } if (pc->isGenerator()) { MOZ_ASSERT_IF(!pc->isAsync(), type == StatementListBody); if (!declareDotGeneratorName()) return null(); Node generator = newDotGeneratorName(); if (!generator) return null(); if (!handler.prependInitialYield(pn, generator)) return null(); } // Declare the 'arguments' and 'this' bindings if necessary before // finishing up the scope so these special bindings get marked as closed // over if necessary. Arrow functions don't have these bindings. if (kind != Arrow) { if (!declareFunctionArgumentsObject()) return null(); if (!declareFunctionThis()) return null(); } return finishLexicalScope(pc->varScope(), pn); } template JSFunction* Parser::newFunction(HandleAtom atom, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, HandleObject proto) { MOZ_ASSERT_IF(kind == Statement, atom != nullptr); RootedFunction fun(context); gc::AllocKind allocKind = gc::AllocKind::FUNCTION; JSFunction::Flags flags; #ifdef DEBUG bool isGlobalSelfHostedBuiltin = false; #endif switch (kind) { case Expression: flags = (generatorKind == NotGenerator ? JSFunction::INTERPRETED_LAMBDA : JSFunction::INTERPRETED_LAMBDA_GENERATOR); break; case Arrow: flags = JSFunction::INTERPRETED_LAMBDA_ARROW; allocKind = gc::AllocKind::FUNCTION_EXTENDED; break; case Method: MOZ_ASSERT(generatorKind == NotGenerator || generatorKind == StarGenerator); flags = (generatorKind == NotGenerator ? JSFunction::INTERPRETED_METHOD : JSFunction::INTERPRETED_METHOD_GENERATOR); allocKind = gc::AllocKind::FUNCTION_EXTENDED; break; case ClassConstructor: case DerivedClassConstructor: flags = JSFunction::INTERPRETED_CLASS_CONSTRUCTOR; allocKind = gc::AllocKind::FUNCTION_EXTENDED; break; case Getter: case GetterNoExpressionClosure: flags = JSFunction::INTERPRETED_GETTER; allocKind = gc::AllocKind::FUNCTION_EXTENDED; break; case Setter: case SetterNoExpressionClosure: flags = JSFunction::INTERPRETED_SETTER; allocKind = gc::AllocKind::FUNCTION_EXTENDED; break; default: MOZ_ASSERT(kind == Statement); #ifdef DEBUG if (options().selfHostingMode && !pc->isFunctionBox()) { isGlobalSelfHostedBuiltin = true; allocKind = gc::AllocKind::FUNCTION_EXTENDED; } #endif flags = (generatorKind == NotGenerator ? JSFunction::INTERPRETED_NORMAL : JSFunction::INTERPRETED_GENERATOR); } // We store the async wrapper in a slot for later access. if (asyncKind == AsyncFunction) allocKind = gc::AllocKind::FUNCTION_EXTENDED; fun = NewFunctionWithProto(context, nullptr, 0, flags, nullptr, atom, proto, allocKind, TenuredObject); if (!fun) return nullptr; if (options().selfHostingMode) { fun->setIsSelfHostedBuiltin(); #ifdef DEBUG if (isGlobalSelfHostedBuiltin) fun->setExtendedSlot(HAS_SELFHOSTED_CANONICAL_NAME_SLOT, BooleanValue(false)); #endif } return fun; } /* * WARNING: Do not call this function directly. * Call either MatchOrInsertSemicolonAfterExpression or * MatchOrInsertSemicolonAfterNonExpression instead, depending on context. */ static bool MatchOrInsertSemicolonHelper(TokenStream& ts, TokenStream::Modifier modifier) { TokenKind tt = TOK_EOF; if (!ts.peekTokenSameLine(&tt, modifier)) return false; if (tt != TOK_EOF && tt != TOK_EOL && tt != TOK_SEMI && tt != TOK_RC) { /* Advance the scanner for proper error location reporting. */ ts.consumeKnownToken(tt, modifier); ts.reportError(JSMSG_SEMI_BEFORE_STMNT); return false; } bool matched; if (!ts.matchToken(&matched, TOK_SEMI, modifier)) return false; if (!matched && modifier == TokenStream::None) ts.addModifierException(TokenStream::OperandIsNone); return true; } static bool MatchOrInsertSemicolonAfterExpression(TokenStream& ts) { return MatchOrInsertSemicolonHelper(ts, TokenStream::None); } static bool MatchOrInsertSemicolonAfterNonExpression(TokenStream& ts) { return MatchOrInsertSemicolonHelper(ts, TokenStream::Operand); } template bool Parser::leaveInnerFunction(ParseContext* outerpc) { MOZ_ASSERT(pc != outerpc); // If the current function allows super.property but cannot have a home // object, i.e., it is an arrow function, we need to propagate the flag to // the outer ParseContext. if (pc->superScopeNeedsHomeObject()) { if (!pc->isArrowFunction()) MOZ_ASSERT(pc->functionBox()->needsHomeObject()); else outerpc->setSuperScopeNeedsHomeObject(); } // Lazy functions inner to another lazy function need to be remembered by // the inner function so that if the outer function is eventually parsed // we do not need any further parsing or processing of the inner function. // // Append the inner function here unconditionally; the vector is only used // if the Parser using outerpc is a syntax parsing. See // Parser::finishFunction. if (!outerpc->innerFunctionsForLazy.append(pc->functionBox()->function())) return false; PropagateTransitiveParseFlags(pc->functionBox(), outerpc->sc()); return true; } template JSAtom* Parser::prefixAccessorName(PropertyType propType, HandleAtom propAtom) { RootedAtom prefix(context); if (propType == PropertyType::Setter || propType == PropertyType::SetterNoExpressionClosure) { prefix = context->names().setPrefix; } else { MOZ_ASSERT(propType == PropertyType::Getter || propType == PropertyType::GetterNoExpressionClosure); prefix = context->names().getPrefix; } RootedString str(context, ConcatStrings(context, prefix, propAtom)); if (!str) return nullptr; return AtomizeString(context, str); } template bool Parser::functionArguments(YieldHandling yieldHandling, FunctionSyntaxKind kind, Node funcpn) { FunctionBox* funbox = pc->functionBox(); bool parenFreeArrow = false; // Modifier for the following tokens. // TokenStream::None for the following cases: // async a => 1 // ^ // // (a) => 1 // ^ // // async (a) => 1 // ^ // // function f(a) {} // ^ // // TokenStream::Operand for the following case: // a => 1 // ^ TokenStream::Modifier firstTokenModifier = TokenStream::None; // Modifier for the the first token in each argument. // can be changed to TokenStream::None for the following case: // async a => 1 // ^ TokenStream::Modifier argModifier = TokenStream::Operand; if (kind == Arrow) { TokenKind tt; // In async function, the first token after `async` is already gotten // with TokenStream::None. // In sync function, the first token is already gotten with // TokenStream::Operand. firstTokenModifier = funbox->isAsync() ? TokenStream::None : TokenStream::Operand; if (!tokenStream.peekToken(&tt, firstTokenModifier)) return false; if (tt == TOK_NAME || tt == TOK_YIELD) { parenFreeArrow = true; argModifier = firstTokenModifier; } } if (!parenFreeArrow) { TokenKind tt; if (!tokenStream.getToken(&tt, firstTokenModifier)) return false; if (tt != TOK_LP) { error(kind == Arrow ? JSMSG_BAD_ARROW_ARGS : JSMSG_PAREN_BEFORE_FORMAL); return false; } // Record the start of function source (for FunctionToString). If we // are parenFreeArrow, we will set this below, after consuming the NAME. funbox->setStart(tokenStream); } Node argsbody = handler.newList(PNK_PARAMSBODY); if (!argsbody) return false; handler.setFunctionFormalParametersAndBody(funcpn, argsbody); bool hasArguments = false; if (parenFreeArrow) { hasArguments = true; } else { bool matched; if (!tokenStream.matchToken(&matched, TOK_RP, TokenStream::Operand)) return false; if (!matched) hasArguments = true; } if (hasArguments) { bool hasRest = false; bool hasDefault = false; bool duplicatedParam = false; bool disallowDuplicateParams = kind == Arrow || kind == Method || kind == ClassConstructor; AtomVector& positionalFormals = pc->positionalFormalParameterNames(); if (IsGetterKind(kind)) { error(JSMSG_ACCESSOR_WRONG_ARGS, "getter", "no", "s"); return false; } while (true) { if (hasRest) { error(JSMSG_PARAMETER_AFTER_REST); return false; } TokenKind tt; if (!tokenStream.getToken(&tt, argModifier)) return false; argModifier = TokenStream::Operand; MOZ_ASSERT_IF(parenFreeArrow, tt == TOK_NAME || tt == TOK_YIELD); if (tt == TOK_TRIPLEDOT) { if (IsSetterKind(kind)) { error(JSMSG_ACCESSOR_WRONG_ARGS, "setter", "one", ""); return false; } disallowDuplicateParams = true; if (duplicatedParam) { // Has duplicated args before the rest parameter. error(JSMSG_BAD_DUP_ARGS); return false; } hasRest = true; funbox->setHasRest(); if (!tokenStream.getToken(&tt)) return false; if (tt != TOK_NAME && tt != TOK_YIELD && tt != TOK_LB && tt != TOK_LC) { error(JSMSG_NO_REST_NAME); return false; } } switch (tt) { case TOK_LB: case TOK_LC: { disallowDuplicateParams = true; if (duplicatedParam) { // Has duplicated args before the destructuring parameter. error(JSMSG_BAD_DUP_ARGS); return false; } funbox->hasDestructuringArgs = true; Node destruct = destructuringDeclarationWithoutYieldOrAwait( DeclarationKind::FormalParameter, yieldHandling, tt); if (!destruct) return false; if (!noteDestructuredPositionalFormalParameter(funcpn, destruct)) return false; break; } case TOK_NAME: case TOK_YIELD: { if (parenFreeArrow) funbox->setStart(tokenStream); if (funbox->isAsync() && tokenStream.currentName() == context->names().await) { // `await` is already gotten as TOK_NAME for the following // case: // // async await => 1 error(JSMSG_RESERVED_ID, "await"); return false; } RootedPropertyName name(context, bindingIdentifier(yieldHandling)); if (!name) return false; if (!notePositionalFormalParameter(funcpn, name, disallowDuplicateParams, &duplicatedParam)) { return false; } if (duplicatedParam) funbox->hasDuplicateParameters = true; break; } default: error(JSMSG_MISSING_FORMAL); return false; } if (positionalFormals.length() >= ARGNO_LIMIT) { error(JSMSG_TOO_MANY_FUN_ARGS); return false; } bool matched; if (!tokenStream.matchToken(&matched, TOK_ASSIGN)) return false; if (matched) { // A default argument without parentheses would look like: // a = expr => body, but both operators are right-associative, so // that would have been parsed as a = (expr => body) instead. // Therefore it's impossible to get here with parenFreeArrow. MOZ_ASSERT(!parenFreeArrow); if (hasRest) { error(JSMSG_REST_WITH_DEFAULT); return false; } disallowDuplicateParams = true; if (duplicatedParam) { error(JSMSG_BAD_DUP_ARGS); return false; } if (!hasDefault) { hasDefault = true; // The Function.length property is the number of formals // before the first default argument. funbox->length = positionalFormals.length() - 1; } funbox->hasParameterExprs = true; Node def_expr = assignExprWithoutYieldOrAwait(yieldHandling); if (!def_expr) return false; if (!handler.setLastFunctionFormalParameterDefault(funcpn, def_expr)) return false; } if (parenFreeArrow || IsSetterKind(kind)) break; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return false; if (!matched) break; if (!hasRest) { if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_RP) { tokenStream.addModifierException(TokenStream::NoneIsOperand); break; } } } if (!parenFreeArrow) { TokenKind tt; if (!tokenStream.getToken(&tt)) return false; if (tt != TOK_RP) { if (IsSetterKind(kind)) { error(JSMSG_ACCESSOR_WRONG_ARGS, "setter", "one", ""); return false; } error(JSMSG_PAREN_AFTER_FORMAL); return false; } } if (!hasDefault) funbox->length = positionalFormals.length() - hasRest; if (funbox->hasParameterExprs && funbox->hasDirectEval()) funbox->hasDirectEvalInParameterExpr = true; funbox->function()->setArgCount(positionalFormals.length()); } else if (IsSetterKind(kind)) { error(JSMSG_ACCESSOR_WRONG_ARGS, "setter", "one", ""); return false; } return true; } template <> bool Parser::skipLazyInnerFunction(ParseNode* pn, uint32_t preludeStart, FunctionSyntaxKind kind, bool tryAnnexB) { // When a lazily-parsed function is called, we only fully parse (and emit) // that function, not any of its nested children. The initial syntax-only // parse recorded the free variables of nested functions and their extents, // so we can skip over them after accounting for their free variables. RootedFunction fun(context, handler.nextLazyInnerFunction()); MOZ_ASSERT(!fun->isLegacyGenerator()); FunctionBox* funbox = newFunctionBox(pn, fun, preludeStart, Directives(/* strict = */ false), fun->generatorKind(), fun->asyncKind(), tryAnnexB); if (!funbox) return false; LazyScript* lazy = fun->lazyScript(); if (lazy->needsHomeObject()) funbox->setNeedsHomeObject(); PropagateTransitiveParseFlags(lazy, pc->sc()); // The position passed to tokenStream.advance() is an offset of the sort // returned by userbuf.offset() and expected by userbuf.rawCharPtrAt(), // while LazyScript::{begin,end} offsets are relative to the outermost // script source. Rooted lazyOuter(context, handler.lazyOuterFunction()); uint32_t userbufBase = lazyOuter->begin() - lazyOuter->column(); if (!tokenStream.advance(fun->lazyScript()->end() - userbufBase)) return false; if (kind == Statement && fun->isExprBody()) { if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return false; } return true; } template <> bool Parser::skipLazyInnerFunction(Node pn, uint32_t preludeStart, FunctionSyntaxKind kind, bool tryAnnexB) { MOZ_CRASH("Cannot skip lazy inner functions when syntax parsing"); } template bool Parser::addExprAndGetNextTemplStrToken(YieldHandling yieldHandling, Node nodeList, TokenKind* ttp) { Node pn = expr(InAllowed, yieldHandling, TripledotProhibited); if (!pn) return false; handler.addList(nodeList, pn); TokenKind tt; if (!tokenStream.getToken(&tt)) return false; if (tt != TOK_RC) { error(JSMSG_TEMPLSTR_UNTERM_EXPR); return false; } return tokenStream.getToken(ttp, TokenStream::TemplateTail); } template bool Parser::taggedTemplate(YieldHandling yieldHandling, Node nodeList, TokenKind tt) { Node callSiteObjNode = handler.newCallSiteObject(pos().begin); if (!callSiteObjNode) return false; handler.addList(nodeList, callSiteObjNode); while (true) { if (!appendToCallSiteObj(callSiteObjNode)) return false; if (tt != TOK_TEMPLATE_HEAD) break; if (!addExprAndGetNextTemplStrToken(yieldHandling, nodeList, &tt)) return false; } handler.setEndPosition(nodeList, callSiteObjNode); return true; } template typename ParseHandler::Node Parser::templateLiteral(YieldHandling yieldHandling) { Node pn = noSubstitutionTemplate(); if (!pn) return null(); Node nodeList = handler.newList(PNK_TEMPLATE_STRING_LIST, pn); if (!nodeList) return null(); TokenKind tt; do { if (!addExprAndGetNextTemplStrToken(yieldHandling, nodeList, &tt)) return null(); pn = noSubstitutionTemplate(); if (!pn) return null(); handler.addList(nodeList, pn); } while (tt == TOK_TEMPLATE_HEAD); return nodeList; } template typename ParseHandler::Node Parser::functionDefinition(uint32_t preludeStart, Node pn, InHandling inHandling, YieldHandling yieldHandling, HandleAtom funName, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB /* = false */) { MOZ_ASSERT_IF(kind == Statement, funName); MOZ_ASSERT_IF(asyncKind == AsyncFunction, generatorKind == StarGenerator); // When fully parsing a LazyScript, we do not fully reparse its inner // functions, which are also lazy. Instead, their free variables and // source extents are recorded and may be skipped. if (handler.canSkipLazyInnerFunctions()) { if (!skipLazyInnerFunction(pn, preludeStart, kind, tryAnnexB)) return null(); return pn; } RootedObject proto(context); if (generatorKind == StarGenerator) { // If we are off the main thread, the generator meta-objects have // already been created by js::StartOffThreadParseScript, so cx will not // be necessary. JSContext* cx = context->maybeJSContext(); proto = GlobalObject::getOrCreateStarGeneratorFunctionPrototype(cx, context->global()); if (!proto) return null(); } RootedFunction fun(context, newFunction(funName, kind, generatorKind, asyncKind, proto)); if (!fun) return null(); // Speculatively parse using the directives of the parent parsing context. // If a directive is encountered (e.g., "use strict") that changes how the // function should have been parsed, we backup and reparse with the new set // of directives. Directives directives(pc); Directives newDirectives = directives; TokenStream::Position start(keepAtoms); tokenStream.tell(&start); // Parse the inner function. The following is a loop as we may attempt to // reparse a function due to failed syntax parsing and encountering new // "use foo" directives. while (true) { if (trySyntaxParseInnerFunction(pn, fun, preludeStart, inHandling, yieldHandling, kind, generatorKind, asyncKind, tryAnnexB, directives, &newDirectives)) { break; } // Return on error. if (tokenStream.hadError() || directives == newDirectives) return null(); // Assignment must be monotonic to prevent infinitely attempting to // reparse. MOZ_ASSERT_IF(directives.strict(), newDirectives.strict()); MOZ_ASSERT_IF(directives.asmJS(), newDirectives.asmJS()); directives = newDirectives; tokenStream.seek(start); // functionFormalParametersAndBody may have already set pn->pn_body before failing. handler.setFunctionFormalParametersAndBody(pn, null()); } return pn; } template <> bool Parser::trySyntaxParseInnerFunction(ParseNode* pn, HandleFunction fun, uint32_t preludeStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB, Directives inheritedDirectives, Directives* newDirectives) { // Try a syntax parse for this inner function. do { // If we're assuming this function is an IIFE, always perform a full // parse to avoid the overhead of a lazy syntax-only parse. Although // the prediction may be incorrect, IIFEs are common enough that it // pays off for lots of code. if (pn->isLikelyIIFE() && generatorKind == NotGenerator) break; Parser* parser = handler.syntaxParser; if (!parser) break; UsedNameTracker::RewindToken token = usedNames.getRewindToken(); // Move the syntax parser to the current position in the stream. TokenStream::Position position(keepAtoms); tokenStream.tell(&position); if (!parser->tokenStream.seek(position, tokenStream)) return false; // Make a FunctionBox before we enter the syntax parser, because |pn| // still expects a FunctionBox to be attached to it during BCE, and // the syntax parser cannot attach one to it. FunctionBox* funbox = newFunctionBox(pn, fun, preludeStart, inheritedDirectives, generatorKind, asyncKind, tryAnnexB); if (!funbox) return false; funbox->initWithEnclosingParseContext(pc, kind); if (!parser->innerFunction(SyntaxParseHandler::NodeGeneric, pc, funbox, preludeStart, inHandling, yieldHandling, kind, inheritedDirectives, newDirectives)) { if (parser->hadAbortedSyntaxParse()) { // Try again with a full parse. UsedNameTracker needs to be // rewound to just before we tried the syntax parse for // correctness. parser->clearAbortedSyntaxParse(); usedNames.rewind(token); MOZ_ASSERT_IF(parser->context->isJSContext(), !parser->context->asJSContext()->isExceptionPending()); break; } return false; } // Advance this parser over tokens processed by the syntax parser. parser->tokenStream.tell(&position); if (!tokenStream.seek(position, parser->tokenStream)) return false; // Update the end position of the parse node. pn->pn_pos.end = tokenStream.currentToken().pos.end; return true; } while (false); // We failed to do a syntax parse above, so do the full parse. return innerFunction(pn, pc, fun, preludeStart, inHandling, yieldHandling, kind, generatorKind, asyncKind, tryAnnexB, inheritedDirectives, newDirectives); } template <> bool Parser::trySyntaxParseInnerFunction(Node pn, HandleFunction fun, uint32_t preludeStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB, Directives inheritedDirectives, Directives* newDirectives) { // This is already a syntax parser, so just parse the inner function. return innerFunction(pn, pc, fun, preludeStart, inHandling, yieldHandling, kind, generatorKind, asyncKind, tryAnnexB, inheritedDirectives, newDirectives); } template bool Parser::innerFunction(Node pn, ParseContext* outerpc, FunctionBox* funbox, uint32_t preludeStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, Directives inheritedDirectives, Directives* newDirectives) { // Note that it is possible for outerpc != this->pc, as we may be // attempting to syntax parse an inner function from an outer full // parser. In that case, outerpc is a ParseContext from the full parser // instead of the current top of the stack of the syntax parser. // Push a new ParseContext. ParseContext funpc(this, funbox, newDirectives); if (!funpc.init()) return false; if (!functionFormalParametersAndBody(inHandling, yieldHandling, pn, kind)) return false; return leaveInnerFunction(outerpc); } template bool Parser::innerFunction(Node pn, ParseContext* outerpc, HandleFunction fun, uint32_t preludeStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB, Directives inheritedDirectives, Directives* newDirectives) { // Note that it is possible for outerpc != this->pc, as we may be // attempting to syntax parse an inner function from an outer full // parser. In that case, outerpc is a ParseContext from the full parser // instead of the current top of the stack of the syntax parser. FunctionBox* funbox = newFunctionBox(pn, fun, preludeStart, inheritedDirectives, generatorKind, asyncKind, tryAnnexB); if (!funbox) return false; funbox->initWithEnclosingParseContext(outerpc, kind); return innerFunction(pn, outerpc, funbox, preludeStart, inHandling, yieldHandling, kind, inheritedDirectives, newDirectives); } template bool Parser::appendToCallSiteObj(Node callSiteObj) { Node cookedNode = noSubstitutionTemplate(); if (!cookedNode) return false; JSAtom* atom = tokenStream.getRawTemplateStringAtom(); if (!atom) return false; Node rawNode = handler.newTemplateStringLiteral(atom, pos()); if (!rawNode) return false; handler.addToCallSiteObject(callSiteObj, rawNode, cookedNode); return true; } template <> ParseNode* Parser::standaloneLazyFunction(HandleFunction fun, bool strict, GeneratorKind generatorKind, FunctionAsyncKind asyncKind) { MOZ_ASSERT(checkOptionsCalled); Node pn = handler.newFunctionStatement(); if (!pn) return null(); Directives directives(strict); FunctionBox* funbox = newFunctionBox(pn, fun, /* preludeStart = */ 0, directives, generatorKind, asyncKind, /* tryAnnexB = */ false); if (!funbox) return null(); funbox->initFromLazyFunction(); Directives newDirectives = directives; ParseContext funpc(this, funbox, &newDirectives); if (!funpc.init()) return null(); // Our tokenStream has no current token, so pn's position is garbage. // Substitute the position of the first token in our source. If the function // is a not-async arrow, use TokenStream::Operand to keep // verifyConsistentModifier from complaining (we will use // TokenStream::Operand in functionArguments). TokenStream::Modifier modifier = (fun->isArrow() && asyncKind == SyncFunction) ? TokenStream::Operand : TokenStream::None; if (!tokenStream.peekTokenPos(&pn->pn_pos, modifier)) return null(); YieldHandling yieldHandling = GetYieldHandling(generatorKind, asyncKind); FunctionSyntaxKind syntaxKind = Statement; if (fun->isClassConstructor()) syntaxKind = ClassConstructor; else if (fun->isMethod()) syntaxKind = Method; else if (fun->isGetter()) syntaxKind = Getter; else if (fun->isSetter()) syntaxKind = Setter; else if (fun->isArrow()) syntaxKind = Arrow; if (!functionFormalParametersAndBody(InAllowed, yieldHandling, pn, syntaxKind)) { MOZ_ASSERT(directives == newDirectives); return null(); } if (!FoldConstants(context, &pn, this)) return null(); return pn; } template bool Parser::functionFormalParametersAndBody(InHandling inHandling, YieldHandling yieldHandling, Node pn, FunctionSyntaxKind kind, Maybe parameterListEnd /* = Nothing() */) { // Given a properly initialized parse context, try to parse an actual // function without concern for conversion to strict mode, use of lazy // parsing and such. FunctionBox* funbox = pc->functionBox(); RootedFunction fun(context, funbox->function()); AutoAwaitIsKeyword awaitIsKeyword(&tokenStream, funbox->isAsync()); if (!functionArguments(yieldHandling, kind, pn)) return false; Maybe varScope; if (funbox->hasParameterExprs) { varScope.emplace(this); if (!varScope->init(pc)) return false; } else { pc->functionScope().useAsVarScope(pc); } if (kind == Arrow) { bool matched; if (!tokenStream.matchToken(&matched, TOK_ARROW)) return false; if (!matched) { error(JSMSG_BAD_ARROW_ARGS); return false; } } // When parsing something for new Function() we have to make sure to // only treat a certain part of the source as a parameter list. if (parameterListEnd.isSome() && parameterListEnd.value() != pos().begin) { error(JSMSG_UNEXPECTED_PARAMLIST_END); return false; } // Parse the function body. FunctionBodyType bodyType = StatementListBody; TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return false; if (tt != TOK_LC) { if ((funbox->isStarGenerator() && !funbox->isAsync()) || kind == Method || kind == GetterNoExpressionClosure || kind == SetterNoExpressionClosure || IsConstructorKind(kind)) { error(JSMSG_CURLY_BEFORE_BODY); return false; } if (kind != Arrow) { #if JS_HAS_EXPR_CLOSURES if (!warnOnceAboutExprClosure()) return false; #else error(JSMSG_CURLY_BEFORE_BODY); return false; #endif } tokenStream.ungetToken(); bodyType = ExpressionBody; #if JS_HAS_EXPR_CLOSURES fun->setIsExprBody(); #endif } // Arrow function parameters inherit yieldHandling from the enclosing // context, but the arrow body doesn't. E.g. in |(a = yield) => yield|, // |yield| in the parameters is either a name or keyword, depending on // whether the arrow function is enclosed in a generator function or not. // Whereas the |yield| in the function body is always parsed as a name. YieldHandling bodyYieldHandling = GetYieldHandling(pc->generatorKind(), pc->asyncKind()); Node body = functionBody(inHandling, bodyYieldHandling, kind, bodyType); if (!body) return false; if ((kind != Method && !IsConstructorKind(kind)) && fun->explicitName()) { RootedPropertyName propertyName(context, fun->explicitName()->asPropertyName()); if (!checkStrictBinding(propertyName, handler.getPosition(pn))) return false; } if (bodyType == StatementListBody) { bool matched; if (!tokenStream.matchToken(&matched, TOK_RC, TokenStream::Operand)) return false; if (!matched) { error(JSMSG_CURLY_AFTER_BODY); return false; } funbox->bufEnd = pos().end; } else { #if !JS_HAS_EXPR_CLOSURES MOZ_ASSERT(kind == Arrow); #endif if (tokenStream.hadError()) return false; funbox->bufEnd = pos().end; if (kind == Statement && !MatchOrInsertSemicolonAfterExpression(tokenStream)) return false; } if (IsMethodDefinitionKind(kind) && pc->superScopeNeedsHomeObject()) funbox->setNeedsHomeObject(); if (!finishFunction()) return false; handler.setEndPosition(body, pos().begin); handler.setEndPosition(pn, pos().end); handler.setFunctionBody(pn, body); return true; } template typename ParseHandler::Node Parser::functionStmt(uint32_t preludeStart, YieldHandling yieldHandling, DefaultHandling defaultHandling, FunctionAsyncKind asyncKind) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_FUNCTION)); // Annex B.3.4 says we can parse function declarations unbraced under if // or else as if it were braced. That is, |if (x) function f() {}| is // parsed as |if (x) { function f() {} }|. Maybe synthesizedStmtForAnnexB; Maybe synthesizedScopeForAnnexB; if (!pc->sc()->strict()) { ParseContext::Statement* stmt = pc->innermostStatement(); if (stmt && stmt->kind() == StatementKind::If) { synthesizedStmtForAnnexB.emplace(pc, StatementKind::Block); synthesizedScopeForAnnexB.emplace(this); if (!synthesizedScopeForAnnexB->init(pc)) return null(); } } // In sloppy mode, Annex B.3.2 allows labelled function declarations. // Otherwise it's a parse error. ParseContext::Statement* declaredInStmt = pc->innermostStatement(); if (declaredInStmt && declaredInStmt->kind() == StatementKind::Label) { MOZ_ASSERT(!pc->sc()->strict(), "labeled functions shouldn't be parsed in strict mode"); // Find the innermost non-label statement. Report an error if it's // unbraced: functions can't appear in it. Otherwise the statement // (or its absence) determines the scope the function's bound in. while (declaredInStmt && declaredInStmt->kind() == StatementKind::Label) declaredInStmt = declaredInStmt->enclosing(); if (declaredInStmt && !StatementKindIsBraced(declaredInStmt->kind())) { error(JSMSG_SLOPPY_FUNCTION_LABEL); return null(); } } TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); GeneratorKind generatorKind = asyncKind == AsyncFunction ? StarGenerator : NotGenerator; if (tt == TOK_MUL) { if (asyncKind != SyncFunction) { error(JSMSG_ASYNC_GENERATOR); return null(); } generatorKind = StarGenerator; if (!tokenStream.getToken(&tt)) return null(); } RootedPropertyName name(context); if (tt == TOK_NAME || tt == TOK_YIELD) { name = bindingIdentifier(yieldHandling); if (!name) return null(); } else if (defaultHandling == AllowDefaultName) { name = context->names().starDefaultStar; tokenStream.ungetToken(); } else { /* Unnamed function expressions are forbidden in statement context. */ error(JSMSG_UNNAMED_FUNCTION_STMT); return null(); } // Note the declared name and check for early errors. bool tryAnnexB = false; if (declaredInStmt) { MOZ_ASSERT(declaredInStmt->kind() != StatementKind::Label); MOZ_ASSERT(StatementKindIsBraced(declaredInStmt->kind())); if (!pc->sc()->strict() && generatorKind == NotGenerator) { // In sloppy mode, try Annex B.3.3 semantics. If making an // additional 'var' binding of the same name does not throw an // early error, do so. This 'var' binding would be assigned // the function object when its declaration is reached, not at // the start of the block. if (!tryDeclareVarForAnnexBLexicalFunction(name, &tryAnnexB)) return null(); } if (!noteDeclaredName(name, DeclarationKind::LexicalFunction, pos())) return null(); } else { if (!noteDeclaredName(name, DeclarationKind::BodyLevelFunction, pos())) return null(); // Body-level functions in modules are always closed over. if (pc->atModuleLevel()) pc->varScope().lookupDeclaredName(name)->value()->setClosedOver(); } Node pn = handler.newFunctionStatement(); if (!pn) return null(); YieldHandling newYieldHandling = GetYieldHandling(generatorKind, asyncKind); Node fun = functionDefinition(preludeStart, pn, InAllowed, newYieldHandling, name, Statement, generatorKind, asyncKind, tryAnnexB); if (!fun) return null(); if (synthesizedStmtForAnnexB) { Node synthesizedStmtList = handler.newStatementList(handler.getPosition(fun)); if (!synthesizedStmtList) return null(); handler.addStatementToList(synthesizedStmtList, fun); return finishLexicalScope(*synthesizedScopeForAnnexB, synthesizedStmtList); } return fun; } template typename ParseHandler::Node Parser::functionExpr(uint32_t preludeStart, InvokedPrediction invoked, FunctionAsyncKind asyncKind) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_FUNCTION)); AutoAwaitIsKeyword awaitIsKeyword(&tokenStream, asyncKind == AsyncFunction); GeneratorKind generatorKind = asyncKind == AsyncFunction ? StarGenerator : NotGenerator; TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); if (tt == TOK_MUL) { if (asyncKind != SyncFunction) { error(JSMSG_ASYNC_GENERATOR); return null(); } generatorKind = StarGenerator; if (!tokenStream.getToken(&tt)) return null(); } YieldHandling yieldHandling = GetYieldHandling(generatorKind, asyncKind); RootedPropertyName name(context); if (tt == TOK_NAME || tt == TOK_YIELD) { name = bindingIdentifier(yieldHandling); if (!name) return null(); } else { tokenStream.ungetToken(); } Node pn = handler.newFunctionExpression(); if (!pn) return null(); if (invoked) pn = handler.setLikelyIIFE(pn); return functionDefinition(preludeStart, pn, InAllowed, yieldHandling, name, Expression, generatorKind, asyncKind); } /* * Return true if this node, known to be an unparenthesized string literal, * could be the string of a directive in a Directive Prologue. Directive * strings never contain escape sequences or line continuations. * isEscapeFreeStringLiteral, below, checks whether the node itself could be * a directive. */ static inline bool IsEscapeFreeStringLiteral(const TokenPos& pos, JSAtom* str) { /* * If the string's length in the source code is its length as a value, * accounting for the quotes, then it must not contain any escape * sequences or line continuations. */ return pos.begin + str->length() + 2 == pos.end; } template bool Parser::checkUnescapedName() { const Token& token = tokenStream.currentToken(); if (!token.nameContainsEscape()) return true; errorAt(token.pos.begin, JSMSG_ESCAPED_KEYWORD); return false; } template <> bool Parser::asmJS(Node list) { // While asm.js could technically be validated and compiled during syntax // parsing, we have no guarantee that some later JS wouldn't abort the // syntax parse and cause us to re-parse (and re-compile) the asm.js module. // For simplicity, unconditionally abort the syntax parse when "use asm" is // encountered so that asm.js is always validated/compiled exactly once // during a full parse. JS_ALWAYS_FALSE(abortIfSyntaxParser()); return false; } template <> bool Parser::asmJS(Node list) { // Disable syntax parsing in anything nested inside the asm.js module. handler.disableSyntaxParser(); // We should be encountering the "use asm" directive for the first time; if // the directive is already, we must have failed asm.js validation and we're // reparsing. In that case, don't try to validate again. A non-null // newDirectives means we're not in a normal function. if (!pc->newDirectives || pc->newDirectives->asmJS()) return true; // If there is no ScriptSource, then we are doing a non-compiling parse and // so we shouldn't (and can't, without a ScriptSource) compile. if (ss == nullptr) return true; pc->functionBox()->useAsm = true; // Attempt to validate and compile this asm.js module. On success, the // tokenStream has been advanced to the closing }. On failure, the // tokenStream is in an indeterminate state and we must reparse the // function from the beginning. Reparsing is triggered by marking that a // new directive has been encountered and returning 'false'. bool validated; if (!CompileAsmJS(context, *this, list, &validated)) return false; if (!validated) { pc->newDirectives->setAsmJS(); return false; } return true; } /* * Recognize Directive Prologue members and directives. Assuming |pn| is a * candidate for membership in a directive prologue, recognize directives and * set |pc|'s flags accordingly. If |pn| is indeed part of a prologue, set its * |pn_prologue| flag. * * Note that the following is a strict mode function: * * function foo() { * "blah" // inserted semi colon * "blurgh" * "use\x20loose" * "use strict" * } * * That is, even though "use\x20loose" can never be a directive, now or in the * future (because of the hex escape), the Directive Prologue extends through it * to the "use strict" statement, which is indeed a directive. */ template bool Parser::maybeParseDirective(Node list, Node possibleDirective, bool* cont) { TokenPos directivePos; JSAtom* directive = handler.isStringExprStatement(possibleDirective, &directivePos); *cont = !!directive; if (!*cont) return true; if (IsEscapeFreeStringLiteral(directivePos, directive)) { // Mark this statement as being a possibly legitimate part of a // directive prologue, so the bytecode emitter won't warn about it being // useless code. (We mustn't just omit the statement entirely yet, as it // could be producing the value of an eval or JSScript execution.) // // Note that even if the string isn't one we recognize as a directive, // the emitter still shouldn't flag it as useless, as it could become a // directive in the future. We don't want to interfere with people // taking advantage of directive-prologue-enabled features that appear // in other browsers first. handler.setInDirectivePrologue(possibleDirective); if (directive == context->names().useStrict) { // Functions with non-simple parameter lists (destructuring, // default or rest parameters) must not contain a "use strict" // directive. if (pc->isFunctionBox()) { FunctionBox* funbox = pc->functionBox(); if (!funbox->hasSimpleParameterList()) { const char* parameterKind = funbox->hasDestructuringArgs ? "destructuring" : funbox->hasParameterExprs ? "default" : "rest"; errorAt(directivePos.begin, JSMSG_STRICT_NON_SIMPLE_PARAMS, parameterKind); return false; } } // We're going to be in strict mode. Note that this scope explicitly // had "use strict"; pc->sc()->setExplicitUseStrict(); if (!pc->sc()->strict()) { // We keep track of the one possible strict violation that could // occur in the directive prologue -- octal escapes -- and // complain now. if (tokenStream.sawOctalEscape()) { error(JSMSG_DEPRECATED_OCTAL); return false; } pc->sc()->strictScript = true; } } else if (directive == context->names().useAsm) { if (pc->isFunctionBox()) return asmJS(list); return warningAt(directivePos.begin, JSMSG_USE_ASM_DIRECTIVE_FAIL); } } return true; } template typename ParseHandler::Node Parser::statementList(YieldHandling yieldHandling) { JS_CHECK_RECURSION(context, return null()); Node pn = handler.newStatementList(pos()); if (!pn) return null(); bool canHaveDirectives = pc->atBodyLevel(); if (canHaveDirectives) tokenStream.clearSawOctalEscape(); bool afterReturn = false; bool warnedAboutStatementsAfterReturn = false; uint32_t statementBegin = 0; for (;;) { TokenKind tt = TOK_EOF; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) { if (tokenStream.isEOF()) isUnexpectedEOF_ = true; return null(); } if (tt == TOK_EOF || tt == TOK_RC) break; if (afterReturn) { if (!tokenStream.peekOffset(&statementBegin, TokenStream::Operand)) return null(); } Node next = statementListItem(yieldHandling, canHaveDirectives); if (!next) { if (tokenStream.isEOF()) isUnexpectedEOF_ = true; return null(); } if (!warnedAboutStatementsAfterReturn) { if (afterReturn) { if (!handler.isStatementPermittedAfterReturnStatement(next)) { if (!warningAt(statementBegin, JSMSG_STMT_AFTER_RETURN)) return null(); warnedAboutStatementsAfterReturn = true; } } else if (handler.isReturnStatement(next)) { afterReturn = true; } } if (canHaveDirectives) { if (!maybeParseDirective(pn, next, &canHaveDirectives)) return null(); } handler.addStatementToList(pn, next); } return pn; } template typename ParseHandler::Node Parser::condition(InHandling inHandling, YieldHandling yieldHandling) { MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_COND); Node pn = exprInParens(inHandling, yieldHandling, TripledotProhibited); if (!pn) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_COND); /* Check for (a = b) and warn about possible (a == b) mistype. */ if (handler.isUnparenthesizedAssignment(pn)) { if (!extraWarning(JSMSG_EQUAL_AS_ASSIGN)) return null(); } return pn; } template bool Parser::matchLabel(YieldHandling yieldHandling, MutableHandle label) { TokenKind tt = TOK_EOF; if (!tokenStream.peekTokenSameLine(&tt, TokenStream::Operand)) return false; if (tt == TOK_NAME || tt == TOK_YIELD) { tokenStream.consumeKnownToken(tt, TokenStream::Operand); label.set(labelIdentifier(yieldHandling)); if (!label) return false; } else { label.set(nullptr); } return true; } template Parser::PossibleError::PossibleError(Parser& parser) : parser_(parser) {} template typename Parser::PossibleError::Error& Parser::PossibleError::error(ErrorKind kind) { if (kind == ErrorKind::Expression) return exprError_; MOZ_ASSERT(kind == ErrorKind::Destructuring); return destructuringError_; } template void Parser::PossibleError::setResolved(ErrorKind kind) { error(kind).state_ = ErrorState::None; } template bool Parser::PossibleError::hasError(ErrorKind kind) { return error(kind).state_ == ErrorState::Pending; } template void Parser::PossibleError::setPending(ErrorKind kind, const TokenPos& pos, unsigned errorNumber) { // Don't overwrite a previously recorded error. if (hasError(kind)) return; // If we report an error later, we'll do it from the position where we set // the state to pending. Error& err = error(kind); err.offset_ = pos.begin; err.errorNumber_ = errorNumber; err.state_ = ErrorState::Pending; } template void Parser::PossibleError::setPendingDestructuringErrorAt(const TokenPos& pos, unsigned errorNumber) { setPending(ErrorKind::Destructuring, pos, errorNumber); } template void Parser::PossibleError::setPendingExpressionErrorAt(const TokenPos& pos, unsigned errorNumber) { setPending(ErrorKind::Expression, pos, errorNumber); } template bool Parser::PossibleError::checkForError(ErrorKind kind) { if (!hasError(kind)) return true; Error& err = error(kind); parser_.errorAt(err.offset_, err.errorNumber_); return false; } template bool Parser::PossibleError::checkForDestructuringError() { // Clear pending expression error, because we're definitely not in an // expression context. setResolved(ErrorKind::Expression); // Report any pending destructuring error. return checkForError(ErrorKind::Destructuring); } template bool Parser::PossibleError::checkForExpressionError() { // Clear pending destructuring error, because we're definitely not in a // destructuring context. setResolved(ErrorKind::Destructuring); // Report any pending expression error. return checkForError(ErrorKind::Expression); } template void Parser::PossibleError::transferErrorTo(ErrorKind kind, PossibleError* other) { if (hasError(kind) && !other->hasError(kind)) { Error& err = error(kind); Error& otherErr = other->error(kind); otherErr.offset_ = err.offset_; otherErr.errorNumber_ = err.errorNumber_; otherErr.state_ = err.state_; } } template void Parser::PossibleError::transferErrorsTo(PossibleError* other) { MOZ_ASSERT(other); MOZ_ASSERT(this != other); MOZ_ASSERT(&parser_ == &other->parser_, "Can't transfer fields to an instance which belongs to a different parser"); transferErrorTo(ErrorKind::Destructuring, other); transferErrorTo(ErrorKind::Expression, other); } template <> bool Parser::checkDestructuringName(ParseNode* expr, Maybe maybeDecl) { MOZ_ASSERT(!handler.isUnparenthesizedDestructuringPattern(expr)); // Parentheses are forbidden around destructuring *patterns* (but allowed // around names). Use our nicer error message for parenthesized, nested // patterns. if (handler.isParenthesizedDestructuringPattern(expr)) { errorAt(expr->pn_pos.begin, JSMSG_BAD_DESTRUCT_PARENS); return false; } // This expression might be in a variable-binding pattern where only plain, // unparenthesized names are permitted. if (maybeDecl) { // Destructuring patterns in declarations must only contain // unparenthesized names. if (!handler.isUnparenthesizedName(expr)) { errorAt(expr->pn_pos.begin, JSMSG_NO_VARIABLE_NAME); return false; } RootedPropertyName name(context, expr->name()); return noteDeclaredName(name, *maybeDecl, expr->pn_pos); } // Otherwise this is an expression in destructuring outside a declaration. if (handler.isNameAnyParentheses(expr)) { if (const char* chars = handler.nameIsArgumentsEvalAnyParentheses(expr, context)) { if (!strictModeErrorAt(expr->pn_pos.begin, JSMSG_BAD_STRICT_ASSIGN, chars)) return false; } return true; } if (handler.isPropertyAccess(expr)) return true; errorAt(expr->pn_pos.begin, JSMSG_BAD_DESTRUCT_TARGET); return false; } template <> bool Parser::checkDestructuringPattern(ParseNode* pattern, Maybe maybeDecl, PossibleError* possibleError /* = nullptr */); template <> bool Parser::checkDestructuringObject(ParseNode* objectPattern, Maybe maybeDecl) { MOZ_ASSERT(objectPattern->isKind(PNK_OBJECT)); for (ParseNode* member = objectPattern->pn_head; member; member = member->pn_next) { ParseNode* target; if (member->isKind(PNK_MUTATEPROTO)) { target = member->pn_kid; } else { MOZ_ASSERT(member->isKind(PNK_COLON) || member->isKind(PNK_SHORTHAND)); MOZ_ASSERT_IF(member->isKind(PNK_SHORTHAND), member->pn_left->isKind(PNK_OBJECT_PROPERTY_NAME) && member->pn_right->isKind(PNK_NAME) && member->pn_left->pn_atom == member->pn_right->pn_atom); target = member->pn_right; } if (handler.isUnparenthesizedAssignment(target)) target = target->pn_left; if (handler.isUnparenthesizedDestructuringPattern(target)) { if (!checkDestructuringPattern(target, maybeDecl)) return false; } else { if (!checkDestructuringName(target, maybeDecl)) return false; } } return true; } template <> bool Parser::checkDestructuringArray(ParseNode* arrayPattern, Maybe maybeDecl) { MOZ_ASSERT(arrayPattern->isKind(PNK_ARRAY)); for (ParseNode* element = arrayPattern->pn_head; element; element = element->pn_next) { if (element->isKind(PNK_ELISION)) continue; ParseNode* target; if (element->isKind(PNK_SPREAD)) { if (element->pn_next) { errorAt(element->pn_next->pn_pos.begin, JSMSG_PARAMETER_AFTER_REST); return false; } target = element->pn_kid; } else if (handler.isUnparenthesizedAssignment(element)) { target = element->pn_left; } else { target = element; } if (handler.isUnparenthesizedDestructuringPattern(target)) { if (!checkDestructuringPattern(target, maybeDecl)) return false; } else { if (!checkDestructuringName(target, maybeDecl)) return false; } } return true; } /* * Destructuring patterns can appear in two kinds of contexts: * * - assignment-like: assignment expressions and |for| loop heads. In * these cases, the patterns' property value positions can be * arbitrary lvalue expressions; the destructuring is just a fancy * assignment. * * - binding-like: |var| and |let| declarations, functions' formal * parameter lists, |catch| clauses, and comprehension tails. In * these cases, the patterns' property value positions must be * simple names; the destructuring defines them as new variables. * * In both cases, other code parses the pattern as an arbitrary * primaryExpr, and then, here in checkDestructuringPattern, verify * that the tree is a valid AssignmentPattern or BindingPattern. * * In assignment-like contexts, we parse the pattern with * pc->inDestructuringDecl clear, so the lvalue expressions in the * pattern are parsed normally. primaryExpr links variable references * into the appropriate use chains; creates placeholder definitions; * and so on. checkDestructuringPattern won't bind any new names and * we specialize lvalues as appropriate. * * In declaration-like contexts, the normal variable reference * processing would just be an obstruction, because we're going to * define the names that appear in the property value positions as new * variables anyway. In this case, we parse the pattern with * pc->inDestructuringDecl set, which directs primaryExpr to leave * whatever name nodes it creates unconnected. Then, here in * checkDestructuringPattern, we require the pattern's property value * positions to be simple names, and define them as appropriate to the * context. */ template <> bool Parser::checkDestructuringPattern(ParseNode* pattern, Maybe maybeDecl, PossibleError* possibleError /* = nullptr */) { if (pattern->isKind(PNK_ARRAYCOMP)) { errorAt(pattern->pn_pos.begin, JSMSG_ARRAY_COMP_LEFTSIDE); return false; } bool isDestructuring = pattern->isKind(PNK_ARRAY) ? checkDestructuringArray(pattern, maybeDecl) : checkDestructuringObject(pattern, maybeDecl); // Report any pending destructuring error. if (isDestructuring && possibleError && !possibleError->checkForDestructuringError()) return false; return isDestructuring; } template <> bool Parser::checkDestructuringPattern(Node pattern, Maybe maybeDecl, PossibleError* possibleError /* = nullptr */) { return abortIfSyntaxParser(); } template typename ParseHandler::Node Parser::destructuringDeclaration(DeclarationKind kind, YieldHandling yieldHandling, TokenKind tt) { MOZ_ASSERT(tokenStream.isCurrentTokenType(tt)); MOZ_ASSERT(tt == TOK_LB || tt == TOK_LC); PossibleError possibleError(*this); Node pattern; { pc->inDestructuringDecl = Some(kind); pattern = primaryExpr(yieldHandling, TripledotProhibited, tt, &possibleError); pc->inDestructuringDecl = Nothing(); } if (!pattern || !checkDestructuringPattern(pattern, Some(kind), &possibleError)) return null(); return pattern; } template typename ParseHandler::Node Parser::destructuringDeclarationWithoutYieldOrAwait(DeclarationKind kind, YieldHandling yieldHandling, TokenKind tt) { uint32_t startYieldOffset = pc->lastYieldOffset; uint32_t startAwaitOffset = pc->lastAwaitOffset; Node res = destructuringDeclaration(kind, yieldHandling, tt); if (res) { if (pc->lastYieldOffset != startYieldOffset) { errorAt(pc->lastYieldOffset, JSMSG_YIELD_IN_DEFAULT); return null(); } if (pc->lastAwaitOffset != startAwaitOffset) { errorAt(pc->lastAwaitOffset, JSMSG_AWAIT_IN_DEFAULT); return null(); } } return res; } template typename ParseHandler::Node Parser::blockStatement(YieldHandling yieldHandling, unsigned errorNumber) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LC)); ParseContext::Statement stmt(pc, StatementKind::Block); ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); Node list = statementList(yieldHandling); if (!list) return null(); MUST_MATCH_TOKEN_MOD(TOK_RC, TokenStream::Operand, errorNumber); return finishLexicalScope(scope, list); } template typename ParseHandler::Node Parser::expressionAfterForInOrOf(ParseNodeKind forHeadKind, YieldHandling yieldHandling) { MOZ_ASSERT(forHeadKind == PNK_FORIN || forHeadKind == PNK_FOROF); Node pn = forHeadKind == PNK_FOROF ? assignExpr(InAllowed, yieldHandling, TripledotProhibited) : expr(InAllowed, yieldHandling, TripledotProhibited); return pn; } template typename ParseHandler::Node Parser::declarationPattern(Node decl, DeclarationKind declKind, TokenKind tt, bool initialDeclaration, YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInOrOfExpression) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LB) || tokenStream.isCurrentTokenType(TOK_LC)); Node pattern = destructuringDeclaration(declKind, yieldHandling, tt); if (!pattern) return null(); if (initialDeclaration && forHeadKind) { bool isForIn, isForOf; if (!matchInOrOf(&isForIn, &isForOf)) return null(); if (isForIn) { *forHeadKind = PNK_FORIN; } else if (isForOf) { *forHeadKind = PNK_FOROF; // Annex B.3.5 has different early errors for vars in for-of loops. if (declKind == DeclarationKind::Var) declKind = DeclarationKind::ForOfVar; } else { *forHeadKind = PNK_FORHEAD; } if (*forHeadKind != PNK_FORHEAD) { *forInOrOfExpression = expressionAfterForInOrOf(*forHeadKind, yieldHandling); if (!*forInOrOfExpression) return null(); return pattern; } } MUST_MATCH_TOKEN(TOK_ASSIGN, JSMSG_BAD_DESTRUCT_DECL); Node init = assignExpr(forHeadKind ? InProhibited : InAllowed, yieldHandling, TripledotProhibited); if (!init) return null(); handler.checkAndSetIsDirectRHSAnonFunction(init); if (forHeadKind) { // For for(;;) declarations, consistency with |for (;| parsing requires // that the ';' first be examined as Operand, even though absence of a // binary operator (examined with modifier None) terminated |init|. // For all other declarations, through ASI's infinite majesty, a next // token on a new line would begin an expression. tokenStream.addModifierException(TokenStream::OperandIsNone); } return handler.newBinary(PNK_ASSIGN, pattern, init); } template bool Parser::initializerInNameDeclaration(Node decl, Node binding, Handle name, DeclarationKind declKind, bool initialDeclaration, YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInOrOfExpression) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_ASSIGN)); uint32_t initializerOffset; if (!tokenStream.peekOffset(&initializerOffset, TokenStream::Operand)) return false; Node initializer = assignExpr(forHeadKind ? InProhibited : InAllowed, yieldHandling, TripledotProhibited); if (!initializer) return false; handler.checkAndSetIsDirectRHSAnonFunction(initializer); if (forHeadKind) { if (initialDeclaration) { bool isForIn, isForOf; if (!matchInOrOf(&isForIn, &isForOf)) return false; // An initialized declaration can't appear in a for-of: // // for (var/let/const x = ... of ...); // BAD if (isForOf) { errorAt(initializerOffset, JSMSG_OF_AFTER_FOR_LOOP_DECL); return false; } if (isForIn) { // Lexical declarations in for-in loops can't be initialized: // // for (let/const x = ... in ...); // BAD if (DeclarationKindIsLexical(declKind)) { errorAt(initializerOffset, JSMSG_IN_AFTER_LEXICAL_FOR_DECL); return false; } // This leaves only initialized for-in |var| declarations. ES6 // forbids these; later ES un-forbids in non-strict mode code. *forHeadKind = PNK_FORIN; if (!strictModeErrorAt(initializerOffset, JSMSG_INVALID_FOR_IN_DECL_WITH_INIT)) return false; *forInOrOfExpression = expressionAfterForInOrOf(PNK_FORIN, yieldHandling); if (!*forInOrOfExpression) return false; } else { *forHeadKind = PNK_FORHEAD; } } else { MOZ_ASSERT(*forHeadKind == PNK_FORHEAD); // In the very rare case of Parser::assignExpr consuming an // ArrowFunction with block body, when full-parsing with the arrow // function being a skipped lazy inner function, we don't have // lookahead for the next token. Do a one-off peek here to be // consistent with what Parser::matchForInOrOf does in the other // arm of this |if|. // // If you think this all sounds pretty code-smelly, you're almost // certainly correct. TokenKind ignored; if (!tokenStream.peekToken(&ignored)) return false; } if (*forHeadKind == PNK_FORHEAD) { // Per Parser::forHeadStart, the semicolon in |for (;| is // ultimately gotten as Operand. But initializer expressions // terminate with the absence of an operator gotten as None, // so we need an exception. tokenStream.addModifierException(TokenStream::OperandIsNone); } } return handler.finishInitializerAssignment(binding, initializer); } template typename ParseHandler::Node Parser::declarationName(Node decl, DeclarationKind declKind, TokenKind tt, bool initialDeclaration, YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInOrOfExpression) { // Anything other than TOK_YIELD or TOK_NAME is an error. if (tt != TOK_NAME && tt != TOK_YIELD) { error(JSMSG_NO_VARIABLE_NAME); return null(); } RootedPropertyName name(context, bindingIdentifier(yieldHandling)); if (!name) return null(); Node binding = newName(name); if (!binding) return null(); TokenPos namePos = pos(); // The '=' context after a variable name in a declaration is an opportunity // for ASI, and thus for the next token to start an ExpressionStatement: // // var foo // VariableDeclaration // /bar/g; // ExpressionStatement // // Therefore get the token here as Operand. bool matched; if (!tokenStream.matchToken(&matched, TOK_ASSIGN, TokenStream::Operand)) return null(); if (matched) { if (!initializerInNameDeclaration(decl, binding, name, declKind, initialDeclaration, yieldHandling, forHeadKind, forInOrOfExpression)) { return null(); } } else { tokenStream.addModifierException(TokenStream::NoneIsOperand); if (initialDeclaration && forHeadKind) { bool isForIn, isForOf; if (!matchInOrOf(&isForIn, &isForOf)) return null(); if (isForIn) { *forHeadKind = PNK_FORIN; } else if (isForOf) { *forHeadKind = PNK_FOROF; // Annex B.3.5 has different early errors for vars in for-of loops. if (declKind == DeclarationKind::Var) declKind = DeclarationKind::ForOfVar; } else { *forHeadKind = PNK_FORHEAD; } } if (forHeadKind && *forHeadKind != PNK_FORHEAD) { *forInOrOfExpression = expressionAfterForInOrOf(*forHeadKind, yieldHandling); if (!*forInOrOfExpression) return null(); } else { // Normal const declarations, and const declarations in for(;;) // heads, must be initialized. if (declKind == DeclarationKind::Const) { errorAt(namePos.begin, JSMSG_BAD_CONST_DECL); return null(); } } } // Note the declared name after knowing whether or not we are in a for-of // loop, due to special early error semantics in Annex B.3.5. if (!noteDeclaredName(name, declKind, namePos)) return null(); return binding; } template typename ParseHandler::Node Parser::declarationList(YieldHandling yieldHandling, ParseNodeKind kind, ParseNodeKind* forHeadKind /* = nullptr */, Node* forInOrOfExpression /* = nullptr */) { MOZ_ASSERT(kind == PNK_VAR || kind == PNK_LET || kind == PNK_CONST); JSOp op; DeclarationKind declKind; switch (kind) { case PNK_VAR: op = JSOP_DEFVAR; declKind = DeclarationKind::Var; break; case PNK_CONST: op = JSOP_DEFCONST; declKind = DeclarationKind::Const; break; case PNK_LET: op = JSOP_DEFLET; declKind = DeclarationKind::Let; break; default: MOZ_CRASH("Unknown declaration kind"); } Node decl = handler.newDeclarationList(kind, op); if (!decl) return null(); bool matched; bool initialDeclaration = true; do { MOZ_ASSERT_IF(!initialDeclaration && forHeadKind, *forHeadKind == PNK_FORHEAD); TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); Node binding = (tt == TOK_LB || tt == TOK_LC) ? declarationPattern(decl, declKind, tt, initialDeclaration, yieldHandling, forHeadKind, forInOrOfExpression) : declarationName(decl, declKind, tt, initialDeclaration, yieldHandling, forHeadKind, forInOrOfExpression); if (!binding) return null(); handler.addList(decl, binding); if (forHeadKind && *forHeadKind != PNK_FORHEAD) break; initialDeclaration = false; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return null(); } while (matched); return decl; } template typename ParseHandler::Node Parser::lexicalDeclaration(YieldHandling yieldHandling, bool isConst) { /* * Parse body-level lets without a new block object. ES6 specs * that an execution environment's initial lexical environment * is the VariableEnvironment, i.e., body-level lets are in * the same environment record as vars. * * However, they cannot be parsed exactly as vars, as ES6 * requires that uninitialized lets throw ReferenceError on use. * * See 8.1.1.1.6 and the note in 13.2.1. */ Node decl = declarationList(yieldHandling, isConst ? PNK_CONST : PNK_LET); if (!decl || !MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); return decl; } template <> bool Parser::namedImportsOrNamespaceImport(TokenKind tt, Node importSpecSet) { if (tt == TOK_LC) { TokenStream::Modifier modifier = TokenStream::KeywordIsName; while (true) { // Handle the forms |import {} from 'a'| and // |import { ..., } from 'a'| (where ... is non empty), by // escaping the loop early if the next token is }. if (!tokenStream.peekToken(&tt, TokenStream::KeywordIsName)) return false; if (tt == TOK_RC) break; // If the next token is a keyword, the previous call to // peekToken matched it as a TOK_NAME, and put it in the // lookahead buffer, so this call will match keywords as well. MUST_MATCH_TOKEN_MOD(TOK_NAME, TokenStream::KeywordIsName, JSMSG_NO_IMPORT_NAME); Rooted importName(context, tokenStream.currentName()); TokenPos importNamePos = pos(); TokenKind maybeAs; if (!tokenStream.peekToken(&maybeAs)) return null(); if (maybeAs == TOK_NAME && tokenStream.nextName() == context->names().as) { tokenStream.consumeKnownToken(TOK_NAME); if (!checkUnescapedName()) return false; TokenKind afterAs; if (!tokenStream.getToken(&afterAs)) return false; if (afterAs != TOK_NAME && afterAs != TOK_YIELD) { error(JSMSG_NO_BINDING_NAME); return false; } } else { // Keywords cannot be bound to themselves, so an import name // that is a keyword is a syntax error if it is not followed // by the keyword 'as'. // See the ImportSpecifier production in ES6 section 15.2.2. if (IsKeyword(importName)) { JSAutoByteString bytes; if (!AtomToPrintableString(context, importName, &bytes)) return false; error(JSMSG_AS_AFTER_RESERVED_WORD, bytes.ptr()); return false; } } RootedPropertyName bindingAtom(context, importedBinding()); if (!bindingAtom) return false; Node bindingName = newName(bindingAtom); if (!bindingName) return false; if (!noteDeclaredName(bindingAtom, DeclarationKind::Import, pos())) return false; Node importNameNode = newName(importName, importNamePos); if (!importNameNode) return false; Node importSpec = handler.newBinary(PNK_IMPORT_SPEC, importNameNode, bindingName); if (!importSpec) return false; handler.addList(importSpecSet, importSpec); bool matched; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return false; if (!matched) { modifier = TokenStream::None; break; } } MUST_MATCH_TOKEN_MOD(TOK_RC, modifier, JSMSG_RC_AFTER_IMPORT_SPEC_LIST); } else { MOZ_ASSERT(tt == TOK_MUL); if (!tokenStream.getToken(&tt)) return false; if (tt != TOK_NAME || tokenStream.currentName() != context->names().as) { error(JSMSG_AS_AFTER_IMPORT_STAR); return false; } if (!checkUnescapedName()) return false; MUST_MATCH_TOKEN(TOK_NAME, JSMSG_NO_BINDING_NAME); Node importName = newName(context->names().star); if (!importName) return false; // Namespace imports are are not indirect bindings but lexical // definitions that hold a module namespace object. They are treated // as const variables which are initialized during the // ModuleDeclarationInstantiation step. RootedPropertyName bindingName(context, importedBinding()); if (!bindingName) return false; Node bindingNameNode = newName(bindingName); if (!bindingNameNode) return false; if (!noteDeclaredName(bindingName, DeclarationKind::Const, pos())) return false; // The namespace import name is currently required to live on the // environment. pc->varScope().lookupDeclaredName(bindingName)->value()->setClosedOver(); Node importSpec = handler.newBinary(PNK_IMPORT_SPEC, importName, bindingNameNode); if (!importSpec) return false; handler.addList(importSpecSet, importSpec); } return true; } template<> bool Parser::namedImportsOrNamespaceImport(TokenKind tt, Node importSpecSet) { MOZ_ALWAYS_FALSE(abortIfSyntaxParser()); return false; } template<> ParseNode* Parser::importDeclaration() { MOZ_ASSERT(tokenStream.currentToken().type == TOK_IMPORT); if (!pc->atModuleLevel()) { error(JSMSG_IMPORT_DECL_AT_TOP_LEVEL); return null(); } uint32_t begin = pos().begin; TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); Node importSpecSet = handler.newList(PNK_IMPORT_SPEC_LIST); if (!importSpecSet) return null(); if (tt == TOK_NAME || tt == TOK_LC || tt == TOK_MUL) { if (tt == TOK_NAME) { // Handle the form |import a from 'b'|, by adding a single import // specifier to the list, with 'default' as the import name and // 'a' as the binding name. This is equivalent to // |import { default as a } from 'b'|. Node importName = newName(context->names().default_); if (!importName) return null(); RootedPropertyName bindingAtom(context, importedBinding()); if (!bindingAtom) return null(); Node bindingName = newName(bindingAtom); if (!bindingName) return null(); if (!noteDeclaredName(bindingAtom, DeclarationKind::Import, pos())) return null(); Node importSpec = handler.newBinary(PNK_IMPORT_SPEC, importName, bindingName); if (!importSpec) return null(); handler.addList(importSpecSet, importSpec); if (!tokenStream.peekToken(&tt)) return null(); if (tt == TOK_COMMA) { tokenStream.consumeKnownToken(tt); if (!tokenStream.getToken(&tt)) return null(); if (tt != TOK_LC && tt != TOK_MUL) { error(JSMSG_NAMED_IMPORTS_OR_NAMESPACE_IMPORT); return null(); } if (!namedImportsOrNamespaceImport(tt, importSpecSet)) return null(); } } else { if (!namedImportsOrNamespaceImport(tt, importSpecSet)) return null(); } if (!tokenStream.getToken(&tt)) return null(); if (tt != TOK_NAME || tokenStream.currentName() != context->names().from) { error(JSMSG_FROM_AFTER_IMPORT_CLAUSE); return null(); } if (!checkUnescapedName()) return null(); MUST_MATCH_TOKEN(TOK_STRING, JSMSG_MODULE_SPEC_AFTER_FROM); } else if (tt == TOK_STRING) { // Handle the form |import 'a'| by leaving the list empty. This is // equivalent to |import {} from 'a'|. importSpecSet->pn_pos.end = importSpecSet->pn_pos.begin; } else { error(JSMSG_DECLARATION_AFTER_IMPORT); return null(); } Node moduleSpec = stringLiteral(); if (!moduleSpec) return null(); if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); ParseNode* node = handler.newImportDeclaration(importSpecSet, moduleSpec, TokenPos(begin, pos().end)); if (!node || !pc->sc()->asModuleContext()->builder.processImport(node)) return null(); return node; } template<> SyntaxParseHandler::Node Parser::importDeclaration() { JS_ALWAYS_FALSE(abortIfSyntaxParser()); return SyntaxParseHandler::NodeFailure; } template<> bool Parser::checkExportedName(JSAtom* exportName) { if (!pc->sc()->asModuleContext()->builder.hasExportedName(exportName)) return true; JSAutoByteString str; if (!AtomToPrintableString(context, exportName, &str)) return false; error(JSMSG_DUPLICATE_EXPORT_NAME, str.ptr()); return false; } template<> bool Parser::checkExportedName(JSAtom* exportName) { MOZ_ALWAYS_FALSE(abortIfSyntaxParser()); return false; } template<> bool Parser::checkExportedNamesForDeclaration(ParseNode* node) { MOZ_ASSERT(node->isArity(PN_LIST)); for (ParseNode* binding = node->pn_head; binding; binding = binding->pn_next) { if (binding->isKind(PNK_ASSIGN)) binding = binding->pn_left; MOZ_ASSERT(binding->isKind(PNK_NAME)); if (!checkExportedName(binding->pn_atom)) return false; } return true; } template<> bool Parser::checkExportedNamesForDeclaration(Node node) { MOZ_ALWAYS_FALSE(abortIfSyntaxParser()); return false; } template<> ParseNode* Parser::exportDeclaration() { MOZ_ASSERT(tokenStream.currentToken().type == TOK_EXPORT); if (!pc->atModuleLevel()) { error(JSMSG_EXPORT_DECL_AT_TOP_LEVEL); return null(); } uint32_t begin = pos().begin; Node kid; TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); switch (tt) { case TOK_LC: { kid = handler.newList(PNK_EXPORT_SPEC_LIST); if (!kid) return null(); while (true) { // Handle the forms |export {}| and |export { ..., }| (where ... // is non empty), by escaping the loop early if the next token // is }. if (!tokenStream.peekToken(&tt)) return null(); if (tt == TOK_RC) break; MUST_MATCH_TOKEN(TOK_NAME, JSMSG_NO_BINDING_NAME); Node bindingName = newName(tokenStream.currentName()); if (!bindingName) return null(); bool foundAs; if (!tokenStream.matchContextualKeyword(&foundAs, context->names().as)) return null(); if (foundAs) MUST_MATCH_TOKEN_MOD(TOK_NAME, TokenStream::KeywordIsName, JSMSG_NO_EXPORT_NAME); Node exportName = newName(tokenStream.currentName()); if (!exportName) return null(); if (!checkExportedName(exportName->pn_atom)) return null(); Node exportSpec = handler.newBinary(PNK_EXPORT_SPEC, bindingName, exportName); if (!exportSpec) return null(); handler.addList(kid, exportSpec); bool matched; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return null(); if (!matched) break; } MUST_MATCH_TOKEN(TOK_RC, JSMSG_RC_AFTER_EXPORT_SPEC_LIST); // Careful! If |from| follows, even on a new line, it must start a // FromClause: // // export { x } // from "foo"; // a single ExportDeclaration // // But if it doesn't, we might have an ASI opportunity in Operand // context, so simply matching a contextual keyword won't work: // // export { x } // ExportDeclaration, terminated by ASI // fro\u006D // ExpressionStatement, the name "from" // // In that case let MatchOrInsertSemicolonAfterNonExpression sort out // ASI or any necessary error. TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_NAME && tokenStream.currentToken().name() == context->names().from && !tokenStream.currentToken().nameContainsEscape()) { MUST_MATCH_TOKEN(TOK_STRING, JSMSG_MODULE_SPEC_AFTER_FROM); Node moduleSpec = stringLiteral(); if (!moduleSpec) return null(); if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); ParseNode* node = handler.newExportFromDeclaration(begin, kid, moduleSpec); if (!node || !pc->sc()->asModuleContext()->builder.processExportFrom(node)) return null(); return node; } tokenStream.ungetToken(); if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); break; } case TOK_MUL: { kid = handler.newList(PNK_EXPORT_SPEC_LIST); if (!kid) return null(); // Handle the form |export *| by adding a special export batch // specifier to the list. Node exportSpec = handler.newNullary(PNK_EXPORT_BATCH_SPEC, JSOP_NOP, pos()); if (!exportSpec) return null(); handler.addList(kid, exportSpec); if (!tokenStream.getToken(&tt)) return null(); if (tt != TOK_NAME || tokenStream.currentName() != context->names().from) { error(JSMSG_FROM_AFTER_EXPORT_STAR); return null(); } if (!checkUnescapedName()) return null(); MUST_MATCH_TOKEN(TOK_STRING, JSMSG_MODULE_SPEC_AFTER_FROM); Node moduleSpec = stringLiteral(); if (!moduleSpec) return null(); if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); ParseNode* node = handler.newExportFromDeclaration(begin, kid, moduleSpec); if (!node || !pc->sc()->asModuleContext()->builder.processExportFrom(node)) return null(); return node; } case TOK_FUNCTION: kid = functionStmt(pos().begin, YieldIsKeyword, NameRequired); if (!kid) return null(); if (!checkExportedName(kid->pn_funbox->function()->explicitName())) return null(); break; case TOK_CLASS: { kid = classDefinition(YieldIsKeyword, ClassStatement, NameRequired); if (!kid) return null(); const ClassNode& cls = kid->as(); MOZ_ASSERT(cls.names()); if (!checkExportedName(cls.names()->innerBinding()->pn_atom)) return null(); break; } case TOK_VAR: kid = declarationList(YieldIsName, PNK_VAR); if (!kid) return null(); if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); if (!checkExportedNamesForDeclaration(kid)) return null(); break; case TOK_DEFAULT: { if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (!checkExportedName(context->names().default_)) return null(); ParseNode* nameNode = nullptr; switch (tt) { case TOK_FUNCTION: kid = functionStmt(pos().begin, YieldIsKeyword, AllowDefaultName); if (!kid) return null(); break; case TOK_CLASS: kid = classDefinition(YieldIsKeyword, ClassStatement, AllowDefaultName); if (!kid) return null(); break; default: { if (tt == TOK_NAME && tokenStream.currentName() == context->names().async) { TokenKind nextSameLine = TOK_EOF; if (!tokenStream.peekTokenSameLine(&nextSameLine)) return null(); if (nextSameLine == TOK_FUNCTION) { tokenStream.consumeKnownToken(nextSameLine); kid = functionStmt(pos().begin, YieldIsName, AllowDefaultName, AsyncFunction); if (!kid) return null(); break; } } tokenStream.ungetToken(); RootedPropertyName name(context, context->names().starDefaultStar); nameNode = newName(name); if (!nameNode) return null(); if (!noteDeclaredName(name, DeclarationKind::Const, pos())) return null(); kid = assignExpr(InAllowed, YieldIsKeyword, TripledotProhibited); if (!kid) return null(); if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); break; } } ParseNode* node = handler.newExportDefaultDeclaration(kid, nameNode, TokenPos(begin, pos().end)); if (!node || !pc->sc()->asModuleContext()->builder.processExport(node)) return null(); return node; } case TOK_CONST: kid = lexicalDeclaration(YieldIsName, /* isConst = */ true); if (!kid) return null(); if (!checkExportedNamesForDeclaration(kid)) return null(); break; case TOK_NAME: if (tokenStream.currentName() == context->names().let) { if (!checkUnescapedName()) return null(); kid = lexicalDeclaration(YieldIsName, /* isConst = */ false); if (!kid) return null(); if (!checkExportedNamesForDeclaration(kid)) return null(); break; } MOZ_FALLTHROUGH; default: error(JSMSG_DECLARATION_AFTER_EXPORT); return null(); } ParseNode* node = handler.newExportDeclaration(kid, TokenPos(begin, pos().end)); if (!node || !pc->sc()->asModuleContext()->builder.processExport(node)) return null(); return node; } template<> SyntaxParseHandler::Node Parser::exportDeclaration() { JS_ALWAYS_FALSE(abortIfSyntaxParser()); return SyntaxParseHandler::NodeFailure; } template typename ParseHandler::Node Parser::expressionStatement(YieldHandling yieldHandling, InvokedPrediction invoked) { tokenStream.ungetToken(); Node pnexpr = expr(InAllowed, yieldHandling, TripledotProhibited, /* possibleError = */ nullptr, invoked); if (!pnexpr) return null(); if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); return handler.newExprStatement(pnexpr, pos().end); } template typename ParseHandler::Node Parser::consequentOrAlternative(YieldHandling yieldHandling) { TokenKind next; if (!tokenStream.peekToken(&next, TokenStream::Operand)) return null(); if (next == TOK_FUNCTION) { // Apply Annex B.3.4 in non-strict code to allow FunctionDeclaration as // the consequent/alternative of an |if| or |else|. Parser::statement // will report the strict mode error. if (!pc->sc()->strict()) { tokenStream.consumeKnownToken(next, TokenStream::Operand); return functionStmt(pos().begin, yieldHandling, NameRequired); } } return statement(yieldHandling); } template typename ParseHandler::Node Parser::ifStatement(YieldHandling yieldHandling) { Vector condList(context), thenList(context); Vector posList(context); Node elseBranch; ParseContext::Statement stmt(pc, StatementKind::If); while (true) { uint32_t begin = pos().begin; /* An IF node has three kids: condition, then, and optional else. */ Node cond = condition(InAllowed, yieldHandling); if (!cond) return null(); TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_SEMI) { if (!extraWarning(JSMSG_EMPTY_CONSEQUENT)) return null(); } Node thenBranch = consequentOrAlternative(yieldHandling); if (!thenBranch) return null(); if (!condList.append(cond) || !thenList.append(thenBranch) || !posList.append(begin)) return null(); bool matched; if (!tokenStream.matchToken(&matched, TOK_ELSE, TokenStream::Operand)) return null(); if (matched) { if (!tokenStream.matchToken(&matched, TOK_IF, TokenStream::Operand)) return null(); if (matched) continue; elseBranch = consequentOrAlternative(yieldHandling); if (!elseBranch) return null(); } else { elseBranch = null(); } break; } for (int i = condList.length() - 1; i >= 0; i--) { elseBranch = handler.newIfStatement(posList[i], condList[i], thenList[i], elseBranch); if (!elseBranch) return null(); } return elseBranch; } template typename ParseHandler::Node Parser::doWhileStatement(YieldHandling yieldHandling) { uint32_t begin = pos().begin; ParseContext::Statement stmt(pc, StatementKind::DoLoop); Node body = statement(yieldHandling); if (!body) return null(); MUST_MATCH_TOKEN_MOD(TOK_WHILE, TokenStream::Operand, JSMSG_WHILE_AFTER_DO); Node cond = condition(InAllowed, yieldHandling); if (!cond) return null(); // The semicolon after do-while is even more optional than most // semicolons in JS. Web compat required this by 2004: // http://bugzilla.mozilla.org/show_bug.cgi?id=238945 // ES3 and ES5 disagreed, but ES6 conforms to Web reality: // https://bugs.ecmascript.org/show_bug.cgi?id=157 // To parse |do {} while (true) false| correctly, use Operand. bool ignored; if (!tokenStream.matchToken(&ignored, TOK_SEMI, TokenStream::Operand)) return null(); return handler.newDoWhileStatement(body, cond, TokenPos(begin, pos().end)); } template typename ParseHandler::Node Parser::whileStatement(YieldHandling yieldHandling) { uint32_t begin = pos().begin; ParseContext::Statement stmt(pc, StatementKind::WhileLoop); Node cond = condition(InAllowed, yieldHandling); if (!cond) return null(); Node body = statement(yieldHandling); if (!body) return null(); return handler.newWhileStatement(begin, cond, body); } template bool Parser::matchInOrOf(bool* isForInp, bool* isForOfp) { TokenKind tt; if (!tokenStream.getToken(&tt)) return false; *isForInp = tt == TOK_IN; *isForOfp = tt == TOK_NAME && tokenStream.currentToken().name() == context->names().of; if (!*isForInp && !*isForOfp) { tokenStream.ungetToken(); } else { if (tt == TOK_NAME && !checkUnescapedName()) return false; } MOZ_ASSERT_IF(*isForInp || *isForOfp, *isForInp != *isForOfp); return true; } template bool Parser::forHeadStart(YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInitialPart, Maybe& forLoopLexicalScope, Node* forInOrOfExpression) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LP)); TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); // Super-duper easy case: |for (;| is a C-style for-loop with no init // component. if (tt == TOK_SEMI) { *forInitialPart = null(); *forHeadKind = PNK_FORHEAD; return true; } // Parsing after |for (var| is also relatively simple (from this method's // point of view). No block-related work complicates matters, so delegate // to Parser::declaration. if (tt == TOK_VAR) { tokenStream.consumeKnownToken(tt, TokenStream::Operand); // Pass null for block object because |var| declarations don't use one. *forInitialPart = declarationList(yieldHandling, PNK_VAR, forHeadKind, forInOrOfExpression); return *forInitialPart != null(); } // Otherwise we have a lexical declaration or an expression. // For-in loop backwards compatibility requires that |let| starting a // for-loop that's not a (new to ES6) for-of loop, in non-strict mode code, // parse as an identifier. (|let| in for-of is always a declaration.) bool parsingLexicalDeclaration = false; bool letIsIdentifier = false; if (tt == TOK_CONST) { parsingLexicalDeclaration = true; tokenStream.consumeKnownToken(tt, TokenStream::Operand); } else if (tt == TOK_NAME && tokenStream.nextName() == context->names().let && !tokenStream.nextNameContainsEscape()) { // We could have a {For,Lexical}Declaration, or we could have a // LeftHandSideExpression with lookahead restrictions so it's not // ambiguous with the former. Check for a continuation of the former // to decide which we have. tokenStream.consumeKnownToken(TOK_NAME, TokenStream::Operand); TokenKind next; if (!tokenStream.peekToken(&next)) return false; parsingLexicalDeclaration = nextTokenContinuesLetDeclaration(next, yieldHandling); if (!parsingLexicalDeclaration) { tokenStream.ungetToken(); letIsIdentifier = true; } } if (parsingLexicalDeclaration) { forLoopLexicalScope.emplace(this); if (!forLoopLexicalScope->init(pc)) return null(); // Push a temporary ForLoopLexicalHead Statement that allows for // lexical declarations, as they are usually allowed only in braced // statements. ParseContext::Statement forHeadStmt(pc, StatementKind::ForLoopLexicalHead); *forInitialPart = declarationList(yieldHandling, tt == TOK_CONST ? PNK_CONST : PNK_LET, forHeadKind, forInOrOfExpression); return *forInitialPart != null(); } uint32_t exprOffset; if (!tokenStream.peekOffset(&exprOffset, TokenStream::Operand)) return false; // Finally, handle for-loops that start with expressions. Pass // |InProhibited| so that |in| isn't parsed in a RelationalExpression as a // binary operator. |in| makes it a for-in loop, *not* an |in| expression. PossibleError possibleError(*this); *forInitialPart = expr(InProhibited, yieldHandling, TripledotProhibited, &possibleError); if (!*forInitialPart) return false; bool isForIn, isForOf; if (!matchInOrOf(&isForIn, &isForOf)) return false; // If we don't encounter 'in'/'of', we have a for(;;) loop. We've handled // the init expression; the caller handles the rest. Allow the Operand // modifier when regetting: Operand must be used to examine the ';' in // |for (;|, and our caller handles this case and that. if (!isForIn && !isForOf) { if (!possibleError.checkForExpressionError()) return false; *forHeadKind = PNK_FORHEAD; tokenStream.addModifierException(TokenStream::OperandIsNone); return true; } MOZ_ASSERT(isForIn != isForOf); // In a for-of loop, 'let' that starts the loop head is a |let| keyword, // per the [lookahead ≠ let] restriction on the LeftHandSideExpression // variant of such loops. Expressions that start with |let| can't be used // here. // // var let = {}; // for (let.prop of [1]) // BAD // break; // // See ES6 13.7. if (isForOf && letIsIdentifier) { errorAt(exprOffset, JSMSG_LET_STARTING_FOROF_LHS); return false; } *forHeadKind = isForIn ? PNK_FORIN : PNK_FOROF; // Verify the left-hand side expression doesn't have a forbidden form. if (handler.isUnparenthesizedDestructuringPattern(*forInitialPart)) { if (!checkDestructuringPattern(*forInitialPart, Nothing(), &possibleError)) return false; } else if (handler.isNameAnyParentheses(*forInitialPart)) { const char* chars = handler.nameIsArgumentsEvalAnyParentheses(*forInitialPart, context); if (chars) { // |chars| is "arguments" or "eval" here. if (!strictModeErrorAt(exprOffset, JSMSG_BAD_STRICT_ASSIGN, chars)) return false; } handler.adjustGetToSet(*forInitialPart); } else if (handler.isPropertyAccess(*forInitialPart)) { // Permitted: no additional testing/fixup needed. } else if (handler.isFunctionCall(*forInitialPart)) { if (!strictModeErrorAt(exprOffset, JSMSG_BAD_FOR_LEFTSIDE)) return false; } else { errorAt(exprOffset, JSMSG_BAD_FOR_LEFTSIDE); return false; } if (!possibleError.checkForExpressionError()) return false; // Finally, parse the iterated expression, making the for-loop's closing // ')' the next token. *forInOrOfExpression = expressionAfterForInOrOf(*forHeadKind, yieldHandling); return *forInOrOfExpression != null(); } template typename ParseHandler::Node Parser::forStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_FOR)); uint32_t begin = pos().begin; ParseContext::Statement stmt(pc, StatementKind::ForLoop); bool isForEach = false; unsigned iflags = 0; if (allowsForEachIn()) { bool matched; if (!tokenStream.matchContextualKeyword(&matched, context->names().each)) return null(); if (matched) { iflags = JSITER_FOREACH; isForEach = true; if (!warnOnceAboutForEach()) return null(); } } MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_AFTER_FOR); // PNK_FORHEAD, PNK_FORIN, or PNK_FOROF depending on the loop type. ParseNodeKind headKind; // |x| in either |for (x; ...; ...)| or |for (x in/of ...)|. Node startNode; // The next two variables are used to implement `for (let/const ...)`. // // We generate an implicit block, wrapping the whole loop, to store loop // variables declared this way. Note that if the loop uses `for (var...)` // instead, those variables go on some existing enclosing scope, so no // implicit block scope is created. // // Both variables remain null/none if the loop is any other form. // The static block scope for the implicit block scope. Maybe forLoopLexicalScope; // The expression being iterated over, for for-in/of loops only. Unused // for for(;;) loops. Node iteratedExpr; // Parse the entirety of the loop-head for a for-in/of loop (so the next // token is the closing ')'): // // for (... in/of ...) ... // ^next token // // ...OR, parse up to the first ';' in a C-style for-loop: // // for (...; ...; ...) ... // ^next token // // In either case the subsequent token can be consistently accessed using // TokenStream::None semantics. if (!forHeadStart(yieldHandling, &headKind, &startNode, forLoopLexicalScope, &iteratedExpr)) { return null(); } MOZ_ASSERT(headKind == PNK_FORIN || headKind == PNK_FOROF || headKind == PNK_FORHEAD); Node forHead; if (headKind == PNK_FORHEAD) { Node init = startNode; if (isForEach) { errorAt(begin, JSMSG_BAD_FOR_EACH_LOOP); return null(); } // Look for an operand: |for (;| means we might have already examined // this semicolon with that modifier. MUST_MATCH_TOKEN_MOD(TOK_SEMI, TokenStream::Operand, JSMSG_SEMI_AFTER_FOR_INIT); TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); Node test; TokenStream::Modifier mod; if (tt == TOK_SEMI) { test = null(); mod = TokenStream::Operand; } else { test = expr(InAllowed, yieldHandling, TripledotProhibited); if (!test) return null(); mod = TokenStream::None; } MUST_MATCH_TOKEN_MOD(TOK_SEMI, mod, JSMSG_SEMI_AFTER_FOR_COND); if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); Node update; if (tt == TOK_RP) { update = null(); mod = TokenStream::Operand; } else { update = expr(InAllowed, yieldHandling, TripledotProhibited); if (!update) return null(); mod = TokenStream::None; } MUST_MATCH_TOKEN_MOD(TOK_RP, mod, JSMSG_PAREN_AFTER_FOR_CTRL); TokenPos headPos(begin, pos().end); forHead = handler.newForHead(init, test, update, headPos); if (!forHead) return null(); } else { MOZ_ASSERT(headKind == PNK_FORIN || headKind == PNK_FOROF); // |target| is the LeftHandSideExpression or declaration to which the // per-iteration value (an arbitrary value exposed by the iteration // protocol, or a string naming a property) is assigned. Node target = startNode; // Parse the rest of the for-in/of head. if (headKind == PNK_FORIN) { stmt.refineForKind(StatementKind::ForInLoop); iflags |= JSITER_ENUMERATE; } else { if (isForEach) { errorAt(begin, JSMSG_BAD_FOR_EACH_LOOP); return null(); } stmt.refineForKind(StatementKind::ForOfLoop); } // Parser::declaration consumed everything up to the closing ')'. That // token follows an {Assignment,}Expression, so the next token must be // consumed as if an operator continued the expression, i.e. as None. MUST_MATCH_TOKEN_MOD(TOK_RP, TokenStream::None, JSMSG_PAREN_AFTER_FOR_CTRL); TokenPos headPos(begin, pos().end); forHead = handler.newForInOrOfHead(headKind, target, iteratedExpr, headPos); if (!forHead) return null(); } Node body = statement(yieldHandling); if (!body) return null(); Node forLoop = handler.newForStatement(begin, forHead, body, iflags); if (!forLoop) return null(); if (forLoopLexicalScope) return finishLexicalScope(*forLoopLexicalScope, forLoop); return forLoop; } template typename ParseHandler::Node Parser::switchStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_SWITCH)); uint32_t begin = pos().begin; MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_SWITCH); Node discriminant = exprInParens(InAllowed, yieldHandling, TripledotProhibited); if (!discriminant) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_SWITCH); MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_SWITCH); ParseContext::Statement stmt(pc, StatementKind::Switch); ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); Node caseList = handler.newStatementList(pos()); if (!caseList) return null(); bool seenDefault = false; TokenKind tt; while (true) { if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_RC) break; uint32_t caseBegin = pos().begin; Node caseExpr; switch (tt) { case TOK_DEFAULT: if (seenDefault) { error(JSMSG_TOO_MANY_DEFAULTS); return null(); } seenDefault = true; caseExpr = null(); // The default case has pn_left == nullptr. break; case TOK_CASE: caseExpr = expr(InAllowed, yieldHandling, TripledotProhibited); if (!caseExpr) return null(); break; default: error(JSMSG_BAD_SWITCH); return null(); } MUST_MATCH_TOKEN(TOK_COLON, JSMSG_COLON_AFTER_CASE); Node body = handler.newStatementList(pos()); if (!body) return null(); bool afterReturn = false; bool warnedAboutStatementsAfterReturn = false; uint32_t statementBegin = 0; while (true) { if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_RC || tt == TOK_CASE || tt == TOK_DEFAULT) break; if (afterReturn) { if (!tokenStream.peekOffset(&statementBegin, TokenStream::Operand)) return null(); } Node stmt = statementListItem(yieldHandling); if (!stmt) return null(); if (!warnedAboutStatementsAfterReturn) { if (afterReturn) { if (!handler.isStatementPermittedAfterReturnStatement(stmt)) { if (!warningAt(statementBegin, JSMSG_STMT_AFTER_RETURN)) return null(); warnedAboutStatementsAfterReturn = true; } } else if (handler.isReturnStatement(stmt)) { afterReturn = true; } } handler.addStatementToList(body, stmt); } Node casepn = handler.newCaseOrDefault(caseBegin, caseExpr, body); if (!casepn) return null(); handler.addCaseStatementToList(caseList, casepn); } caseList = finishLexicalScope(scope, caseList); if (!caseList) return null(); handler.setEndPosition(caseList, pos().end); return handler.newSwitchStatement(begin, discriminant, caseList); } template typename ParseHandler::Node Parser::continueStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_CONTINUE)); uint32_t begin = pos().begin; RootedPropertyName label(context); if (!matchLabel(yieldHandling, &label)) return null(); // Labeled 'continue' statements target the nearest labeled loop // statements with the same label. Unlabeled 'continue' statements target // the innermost loop statement. auto isLoop = [](ParseContext::Statement* stmt) { return StatementKindIsLoop(stmt->kind()); }; if (label) { ParseContext::Statement* stmt = pc->innermostStatement(); bool foundLoop = false; for (;;) { stmt = ParseContext::Statement::findNearest(stmt, isLoop); if (!stmt) { if (foundLoop) error(JSMSG_LABEL_NOT_FOUND); else errorAt(begin, JSMSG_BAD_CONTINUE); return null(); } foundLoop = true; // Is it labeled by our label? bool foundTarget = false; stmt = stmt->enclosing(); while (stmt && stmt->is()) { if (stmt->as().label() == label) { foundTarget = true; break; } stmt = stmt->enclosing(); } if (foundTarget) break; } } else if (!pc->findInnermostStatement(isLoop)) { error(JSMSG_BAD_CONTINUE); return null(); } if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); return handler.newContinueStatement(label, TokenPos(begin, pos().end)); } template typename ParseHandler::Node Parser::breakStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_BREAK)); uint32_t begin = pos().begin; RootedPropertyName label(context); if (!matchLabel(yieldHandling, &label)) return null(); // Labeled 'break' statements target the nearest labeled statements (could // be any kind) with the same label. Unlabeled 'break' statements target // the innermost loop or switch statement. if (label) { auto hasSameLabel = [&label](ParseContext::LabelStatement* stmt) { return stmt->label() == label; }; if (!pc->findInnermostStatement(hasSameLabel)) { error(JSMSG_LABEL_NOT_FOUND); return null(); } } else { auto isBreakTarget = [](ParseContext::Statement* stmt) { return StatementKindIsUnlabeledBreakTarget(stmt->kind()); }; if (!pc->findInnermostStatement(isBreakTarget)) { errorAt(begin, JSMSG_TOUGH_BREAK); return null(); } } if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); return handler.newBreakStatement(label, TokenPos(begin, pos().end)); } template typename ParseHandler::Node Parser::returnStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_RETURN)); uint32_t begin = pos().begin; MOZ_ASSERT(pc->isFunctionBox()); pc->functionBox()->usesReturn = true; // Parse an optional operand. // // This is ugly, but we don't want to require a semicolon. Node exprNode; TokenKind tt = TOK_EOF; if (!tokenStream.peekTokenSameLine(&tt, TokenStream::Operand)) return null(); switch (tt) { case TOK_EOL: case TOK_EOF: case TOK_SEMI: case TOK_RC: exprNode = null(); pc->funHasReturnVoid = true; break; default: { exprNode = expr(InAllowed, yieldHandling, TripledotProhibited); if (!exprNode) return null(); pc->funHasReturnExpr = true; } } if (exprNode) { if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); } else { if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); } Node pn = handler.newReturnStatement(exprNode, TokenPos(begin, pos().end)); if (!pn) return null(); /* Disallow "return v;" in legacy generators. */ if (pc->isLegacyGenerator() && exprNode) { errorAt(begin, JSMSG_BAD_GENERATOR_RETURN); return null(); } return pn; } template typename ParseHandler::Node Parser::newYieldExpression(uint32_t begin, typename ParseHandler::Node expr, bool isYieldStar) { Node generator = newDotGeneratorName(); if (!generator) return null(); if (isYieldStar) return handler.newYieldStarExpression(begin, expr, generator); return handler.newYieldExpression(begin, expr, generator); } template typename ParseHandler::Node Parser::newAwaitExpression(uint32_t begin, typename ParseHandler::Node expr) { Node generator = newDotGeneratorName(); if (!generator) return null(); return handler.newAwaitExpression(begin, expr, generator); } template typename ParseHandler::Node Parser::yieldExpression(InHandling inHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_YIELD)); uint32_t begin = pos().begin; switch (pc->generatorKind()) { case StarGenerator: { MOZ_ASSERT(pc->isFunctionBox()); pc->lastYieldOffset = begin; Node exprNode; ParseNodeKind kind = PNK_YIELD; TokenKind tt = TOK_EOF; if (!tokenStream.peekTokenSameLine(&tt, TokenStream::Operand)) return null(); switch (tt) { // TOK_EOL is special; it implements the [no LineTerminator here] // quirk in the grammar. case TOK_EOL: // The rest of these make up the complete set of tokens that can // appear after any of the places where AssignmentExpression is used // throughout the grammar. Conveniently, none of them can also be the // start an expression. case TOK_EOF: case TOK_SEMI: case TOK_RC: case TOK_RB: case TOK_RP: case TOK_COLON: case TOK_COMMA: case TOK_IN: // No value. exprNode = null(); tokenStream.addModifierException(TokenStream::NoneIsOperand); break; case TOK_MUL: kind = PNK_YIELD_STAR; tokenStream.consumeKnownToken(TOK_MUL, TokenStream::Operand); MOZ_FALLTHROUGH; default: exprNode = assignExpr(inHandling, YieldIsKeyword, TripledotProhibited); if (!exprNode) return null(); } return newYieldExpression(begin, exprNode, kind == PNK_YIELD_STAR); } case NotGenerator: // We are in code that has not seen a yield, but we are in JS 1.7 or // later. Try to transition to being a legacy generator. MOZ_ASSERT(tokenStream.versionNumber() >= JSVERSION_1_7); MOZ_ASSERT(pc->lastYieldOffset == ParseContext::NoYieldOffset); if (!abortIfSyntaxParser()) return null(); if (!pc->isFunctionBox()) { error(JSMSG_BAD_RETURN_OR_YIELD, js_yield_str); return null(); } if (pc->functionBox()->isArrow()) { errorAt(begin, JSMSG_YIELD_IN_ARROW, js_yield_str); return null(); } if (pc->functionBox()->function()->isMethod() || pc->functionBox()->function()->isGetter() || pc->functionBox()->function()->isSetter()) { errorAt(begin, JSMSG_YIELD_IN_METHOD, js_yield_str); return null(); } if (pc->funHasReturnExpr #if JS_HAS_EXPR_CLOSURES || pc->functionBox()->function()->isExprBody() #endif ) { /* As in Python (see PEP-255), disallow return v; in generators. */ errorAt(begin, JSMSG_BAD_GENERATOR_RETURN); return null(); } pc->functionBox()->setGeneratorKind(LegacyGenerator); MOZ_FALLTHROUGH; case LegacyGenerator: { // We are in a legacy generator: a function that has already seen a // yield. MOZ_ASSERT(pc->isFunctionBox()); pc->lastYieldOffset = begin; // Legacy generators do not require a value. Node exprNode; TokenKind tt = TOK_EOF; if (!tokenStream.peekTokenSameLine(&tt, TokenStream::Operand)) return null(); switch (tt) { case TOK_EOF: case TOK_EOL: case TOK_SEMI: case TOK_RC: case TOK_RB: case TOK_RP: case TOK_COLON: case TOK_COMMA: // No value. exprNode = null(); tokenStream.addModifierException(TokenStream::NoneIsOperand); break; default: exprNode = assignExpr(inHandling, YieldIsKeyword, TripledotProhibited); if (!exprNode) return null(); } return newYieldExpression(begin, exprNode); } } MOZ_CRASH("yieldExpr"); } template typename ParseHandler::Node Parser::withStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_WITH)); uint32_t begin = pos().begin; // Usually we want the constructs forbidden in strict mode code to be a // subset of those that ContextOptions::extraWarnings() warns about, and we // use strictModeError directly. But while 'with' is forbidden in strict // mode code, it doesn't even merit a warning in non-strict code. See // https://bugzilla.mozilla.org/show_bug.cgi?id=514576#c1. if (pc->sc()->strict()) { if (!strictModeError(JSMSG_STRICT_CODE_WITH)) return null(); } MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_WITH); Node objectExpr = exprInParens(InAllowed, yieldHandling, TripledotProhibited); if (!objectExpr) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_WITH); Node innerBlock; { ParseContext::Statement stmt(pc, StatementKind::With); innerBlock = statement(yieldHandling); if (!innerBlock) return null(); } pc->sc()->setBindingsAccessedDynamically(); return handler.newWithStatement(begin, objectExpr, innerBlock); } template typename ParseHandler::Node Parser::labeledItem(YieldHandling yieldHandling) { TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_FUNCTION) { TokenKind next; if (!tokenStream.peekToken(&next)) return null(); // GeneratorDeclaration is only matched by HoistableDeclaration in // StatementListItem, so generators can't be inside labels. if (next == TOK_MUL) { error(JSMSG_GENERATOR_LABEL); return null(); } // Per 13.13.1 it's a syntax error if LabelledItem: FunctionDeclaration // is ever matched. Per Annex B.3.2 that modifies this text, this // applies only to strict mode code. if (pc->sc()->strict()) { error(JSMSG_FUNCTION_LABEL); return null(); } return functionStmt(pos().begin, yieldHandling, NameRequired); } tokenStream.ungetToken(); return statement(yieldHandling); } template typename ParseHandler::Node Parser::labeledStatement(YieldHandling yieldHandling) { RootedPropertyName label(context, labelIdentifier(yieldHandling)); if (!label) return null(); auto hasSameLabel = [&label](ParseContext::LabelStatement* stmt) { return stmt->label() == label; }; uint32_t begin = pos().begin; if (pc->findInnermostStatement(hasSameLabel)) { errorAt(begin, JSMSG_DUPLICATE_LABEL); return null(); } tokenStream.consumeKnownToken(TOK_COLON); /* Push a label struct and parse the statement. */ ParseContext::LabelStatement stmt(pc, label); Node pn = labeledItem(yieldHandling); if (!pn) return null(); return handler.newLabeledStatement(label, pn, begin); } template typename ParseHandler::Node Parser::throwStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_THROW)); uint32_t begin = pos().begin; /* ECMA-262 Edition 3 says 'throw [no LineTerminator here] Expr'. */ TokenKind tt = TOK_EOF; if (!tokenStream.peekTokenSameLine(&tt, TokenStream::Operand)) return null(); if (tt == TOK_EOF || tt == TOK_SEMI || tt == TOK_RC) { error(JSMSG_MISSING_EXPR_AFTER_THROW); return null(); } if (tt == TOK_EOL) { error(JSMSG_LINE_BREAK_AFTER_THROW); return null(); } Node throwExpr = expr(InAllowed, yieldHandling, TripledotProhibited); if (!throwExpr) return null(); if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); return handler.newThrowStatement(throwExpr, TokenPos(begin, pos().end)); } template typename ParseHandler::Node Parser::tryStatement(YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_TRY)); uint32_t begin = pos().begin; /* * try nodes are ternary. * kid1 is the try statement * kid2 is the catch node list or null * kid3 is the finally statement * * catch nodes are ternary. * kid1 is the lvalue (TOK_NAME, TOK_LB, or TOK_LC) * kid2 is the catch guard or null if no guard * kid3 is the catch block * * catch lvalue nodes are either: * TOK_NAME for a single identifier * TOK_RB or TOK_RC for a destructuring left-hand side * * finally nodes are TOK_LC statement lists. */ Node innerBlock; { MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_TRY); ParseContext::Statement stmt(pc, StatementKind::Try); ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); innerBlock = statementList(yieldHandling); if (!innerBlock) return null(); innerBlock = finishLexicalScope(scope, innerBlock); if (!innerBlock) return null(); MUST_MATCH_TOKEN_MOD(TOK_RC, TokenStream::Operand, JSMSG_CURLY_AFTER_TRY); } bool hasUnconditionalCatch = false; Node catchList = null(); TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); if (tt == TOK_CATCH) { catchList = handler.newCatchList(); if (!catchList) return null(); do { Node pnblock; /* Check for another catch after unconditional catch. */ if (hasUnconditionalCatch) { error(JSMSG_CATCH_AFTER_GENERAL); return null(); } /* * Create a lexical scope node around the whole catch clause, * including the head. */ ParseContext::Statement stmt(pc, StatementKind::Catch); ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); /* * Legal catch forms are: * catch (lhs) * catch (lhs if ) * where lhs is a name or a destructuring left-hand side. * (the latter is legal only #ifdef JS_HAS_CATCH_GUARD) */ MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_CATCH); if (!tokenStream.getToken(&tt)) return null(); Node catchName; switch (tt) { case TOK_LB: case TOK_LC: catchName = destructuringDeclaration(DeclarationKind::CatchParameter, yieldHandling, tt); if (!catchName) return null(); break; case TOK_NAME: case TOK_YIELD: { RootedPropertyName param(context, bindingIdentifier(yieldHandling)); if (!param) return null(); catchName = newName(param); if (!catchName) return null(); if (!noteDeclaredName(param, DeclarationKind::SimpleCatchParameter, pos())) return null(); break; } default: error(JSMSG_CATCH_IDENTIFIER); return null(); } Node catchGuard = null(); #if JS_HAS_CATCH_GUARD /* * We use 'catch (x if x === 5)' (not 'catch (x : x === 5)') * to avoid conflicting with the JS2/ECMAv4 type annotation * catchguard syntax. */ bool matched; if (!tokenStream.matchToken(&matched, TOK_IF)) return null(); if (matched) { catchGuard = expr(InAllowed, yieldHandling, TripledotProhibited); if (!catchGuard) return null(); } #endif MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_CATCH); MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_CATCH); Node catchBody = catchBlockStatement(yieldHandling, scope); if (!catchBody) return null(); if (!catchGuard) hasUnconditionalCatch = true; pnblock = finishLexicalScope(scope, catchBody); if (!pnblock) return null(); if (!handler.addCatchBlock(catchList, pnblock, catchName, catchGuard, catchBody)) return null(); handler.setEndPosition(catchList, pos().end); handler.setEndPosition(pnblock, pos().end); if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); } while (tt == TOK_CATCH); } Node finallyBlock = null(); if (tt == TOK_FINALLY) { MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_FINALLY); ParseContext::Statement stmt(pc, StatementKind::Finally); ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); finallyBlock = statementList(yieldHandling); if (!finallyBlock) return null(); finallyBlock = finishLexicalScope(scope, finallyBlock); if (!finallyBlock) return null(); MUST_MATCH_TOKEN_MOD(TOK_RC, TokenStream::Operand, JSMSG_CURLY_AFTER_FINALLY); } else { tokenStream.ungetToken(); } if (!catchList && !finallyBlock) { error(JSMSG_CATCH_OR_FINALLY); return null(); } return handler.newTryStatement(begin, innerBlock, catchList, finallyBlock); } template typename ParseHandler::Node Parser::catchBlockStatement(YieldHandling yieldHandling, ParseContext::Scope& catchParamScope) { ParseContext::Statement stmt(pc, StatementKind::Block); // ES 13.15.7 CatchClauseEvaluation // // Step 8 means that the body of a catch block always has an additional // lexical scope. ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); // The catch parameter names cannot be redeclared inside the catch // block, so declare the name in the inner scope. if (!scope.addCatchParameters(pc, catchParamScope)) return null(); Node list = statementList(yieldHandling); if (!list) return null(); MUST_MATCH_TOKEN_MOD(TOK_RC, TokenStream::Operand, JSMSG_CURLY_AFTER_CATCH); // The catch parameter names are not bound in the body scope, so remove // them before generating bindings. scope.removeCatchParameters(pc, catchParamScope); return finishLexicalScope(scope, list); } template typename ParseHandler::Node Parser::debuggerStatement() { TokenPos p; p.begin = pos().begin; if (!MatchOrInsertSemicolonAfterNonExpression(tokenStream)) return null(); p.end = pos().end; pc->sc()->setBindingsAccessedDynamically(); pc->sc()->setHasDebuggerStatement(); return handler.newDebuggerStatement(p); } static JSOp JSOpFromPropertyType(PropertyType propType) { switch (propType) { case PropertyType::Getter: case PropertyType::GetterNoExpressionClosure: return JSOP_INITPROP_GETTER; case PropertyType::Setter: case PropertyType::SetterNoExpressionClosure: return JSOP_INITPROP_SETTER; case PropertyType::Normal: case PropertyType::Method: case PropertyType::GeneratorMethod: case PropertyType::AsyncMethod: case PropertyType::Constructor: case PropertyType::DerivedConstructor: return JSOP_INITPROP; default: MOZ_CRASH("unexpected property type"); } } template typename ParseHandler::Node Parser::classDefinition(YieldHandling yieldHandling, ClassContext classContext, DefaultHandling defaultHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_CLASS)); bool savedStrictness = setLocalStrictMode(true); TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); RootedPropertyName name(context); if (tt == TOK_NAME || tt == TOK_YIELD) { name = bindingIdentifier(yieldHandling); if (!name) return null(); } else if (classContext == ClassStatement) { if (defaultHandling == AllowDefaultName) { name = context->names().starDefaultStar; tokenStream.ungetToken(); } else { // Class statements must have a bound name error(JSMSG_UNNAMED_CLASS_STMT); return null(); } } else { // Make sure to put it back, whatever it was tokenStream.ungetToken(); } RootedAtom propAtom(context); // A named class creates a new lexical scope with a const binding of the // class name. Maybe classStmt; Maybe classScope; if (name) { classStmt.emplace(pc, StatementKind::Block); classScope.emplace(this); if (!classScope->init(pc)) return null(); } // Because the binding definitions keep track of their blockId, we need to // create at least the inner binding later. Keep track of the name's position // in order to provide it for the nodes created later. TokenPos namePos = pos(); Node classHeritage = null(); bool hasHeritage; if (!tokenStream.matchToken(&hasHeritage, TOK_EXTENDS)) return null(); if (hasHeritage) { if (!tokenStream.getToken(&tt)) return null(); classHeritage = memberExpr(yieldHandling, TripledotProhibited, tt); if (!classHeritage) return null(); } MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_CLASS); Node classMethods = handler.newClassMethodList(pos().begin); if (!classMethods) return null(); bool seenConstructor = false; for (;;) { TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::KeywordIsName)) return null(); if (tt == TOK_RC) break; if (tt == TOK_SEMI) continue; bool isStatic = false; if (tt == TOK_NAME && tokenStream.currentName() == context->names().static_) { if (!tokenStream.peekToken(&tt, TokenStream::KeywordIsName)) return null(); if (tt == TOK_RC) { tokenStream.consumeKnownToken(tt, TokenStream::KeywordIsName); error(JSMSG_UNEXPECTED_TOKEN, "property name", TokenKindToDesc(tt)); return null(); } if (tt != TOK_LP) { if (!checkUnescapedName()) return null(); isStatic = true; } else { tokenStream.addModifierException(TokenStream::NoneIsKeywordIsName); tokenStream.ungetToken(); } } else { tokenStream.ungetToken(); } uint32_t nameOffset; if (!tokenStream.peekOffset(&nameOffset)) return null(); PropertyType propType; Node propName = propertyName(yieldHandling, classMethods, &propType, &propAtom); if (!propName) return null(); if (propType != PropertyType::Getter && propType != PropertyType::Setter && propType != PropertyType::Method && propType != PropertyType::GeneratorMethod && propType != PropertyType::AsyncMethod && propType != PropertyType::Constructor && propType != PropertyType::DerivedConstructor) { errorAt(nameOffset, JSMSG_BAD_METHOD_DEF); return null(); } if (propType == PropertyType::Getter) propType = PropertyType::GetterNoExpressionClosure; if (propType == PropertyType::Setter) propType = PropertyType::SetterNoExpressionClosure; if (!isStatic && propAtom == context->names().constructor) { if (propType != PropertyType::Method) { errorAt(nameOffset, JSMSG_BAD_METHOD_DEF); return null(); } if (seenConstructor) { errorAt(nameOffset, JSMSG_DUPLICATE_PROPERTY, "constructor"); return null(); } seenConstructor = true; propType = hasHeritage ? PropertyType::DerivedConstructor : PropertyType::Constructor; } else if (isStatic && propAtom == context->names().prototype) { errorAt(nameOffset, JSMSG_BAD_METHOD_DEF); return null(); } RootedAtom funName(context); switch (propType) { case PropertyType::GetterNoExpressionClosure: case PropertyType::SetterNoExpressionClosure: if (!tokenStream.isCurrentTokenType(TOK_RB)) { funName = prefixAccessorName(propType, propAtom); if (!funName) return null(); } break; case PropertyType::Constructor: case PropertyType::DerivedConstructor: funName = name; break; default: if (!tokenStream.isCurrentTokenType(TOK_RB)) funName = propAtom; } Node fn = methodDefinition(nameOffset, propType, funName); if (!fn) return null(); handler.checkAndSetIsDirectRHSAnonFunction(fn); JSOp op = JSOpFromPropertyType(propType); if (!handler.addClassMethodDefinition(classMethods, propName, fn, op, isStatic)) return null(); } Node nameNode = null(); Node methodsOrBlock = classMethods; if (name) { // The inner name is immutable. if (!noteDeclaredName(name, DeclarationKind::Const, namePos)) return null(); Node innerName = newName(name, namePos); if (!innerName) return null(); Node classBlock = finishLexicalScope(*classScope, classMethods); if (!classBlock) return null(); methodsOrBlock = classBlock; // Pop the inner scope. classScope.reset(); classStmt.reset(); Node outerName = null(); if (classContext == ClassStatement) { // The outer name is mutable. if (!noteDeclaredName(name, DeclarationKind::Let, namePos)) return null(); outerName = newName(name, namePos); if (!outerName) return null(); } nameNode = handler.newClassNames(outerName, innerName, namePos); if (!nameNode) return null(); } MOZ_ALWAYS_TRUE(setLocalStrictMode(savedStrictness)); return handler.newClass(nameNode, classHeritage, methodsOrBlock); } template bool Parser::nextTokenContinuesLetDeclaration(TokenKind next, YieldHandling yieldHandling) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_NAME)); MOZ_ASSERT(tokenStream.currentName() == context->names().let); MOZ_ASSERT(!tokenStream.currentToken().nameContainsEscape()); #ifdef DEBUG TokenKind verify; MOZ_ALWAYS_TRUE(tokenStream.peekToken(&verify)); MOZ_ASSERT(next == verify); #endif // Destructuring is (for once) the easy case. if (next == TOK_LB || next == TOK_LC) return true; // Otherwise a let declaration must have a name. if (next == TOK_NAME) { if (tokenStream.nextName() == context->names().yield) { MOZ_ASSERT(tokenStream.nextNameContainsEscape(), "token stream should interpret unescaped 'yield' as TOK_YIELD"); // Same as |next == TOK_YIELD|. return yieldHandling == YieldIsName; } // One non-"yield" TOK_NAME edge case deserves special comment. // Consider this: // // let // not an ASI opportunity // let; // // Static semantics in §13.3.1.1 turn a LexicalDeclaration that binds // "let" into an early error. Does this retroactively permit ASI so // that we should parse this as two ExpressionStatements? No. ASI // resolves during parsing. Static semantics only apply to the full // parse tree with ASI applied. No backsies! return true; } // If we have the name "yield", the grammar parameter exactly states // whether this is okay. (This wasn't true for SpiderMonkey's ancient // legacy generator syntax, but that's dead now.) If YieldIsName, // declaration-parsing code will (if necessary) enforce a strict mode // restriction on defining "yield". If YieldIsKeyword, consider this the // end of the declaration, in case ASI induces a semicolon that makes the // "yield" valid. if (next == TOK_YIELD) return yieldHandling == YieldIsName; // Otherwise not a let declaration. return false; } template typename ParseHandler::Node Parser::variableStatement(YieldHandling yieldHandling) { Node vars = declarationList(yieldHandling, PNK_VAR); if (!vars) return null(); if (!MatchOrInsertSemicolonAfterExpression(tokenStream)) return null(); return vars; } template typename ParseHandler::Node Parser::statement(YieldHandling yieldHandling) { MOZ_ASSERT(checkOptionsCalled); JS_CHECK_RECURSION(context, return null()); TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); switch (tt) { // BlockStatement[?Yield, ?Return] case TOK_LC: return blockStatement(yieldHandling); // VariableStatement[?Yield] case TOK_VAR: return variableStatement(yieldHandling); // EmptyStatement case TOK_SEMI: return handler.newEmptyStatement(pos()); // ExpressionStatement[?Yield]. case TOK_YIELD: { // Don't use a ternary operator here due to obscure linker issues // around using static consts in the arms of a ternary. TokenStream::Modifier modifier; if (yieldExpressionsSupported()) modifier = TokenStream::Operand; else modifier = TokenStream::None; TokenKind next; if (!tokenStream.peekToken(&next, modifier)) return null(); if (next == TOK_COLON) return labeledStatement(yieldHandling); return expressionStatement(yieldHandling); } case TOK_NAME: { TokenKind next; if (!tokenStream.peekToken(&next)) return null(); // |let| here can only be an Identifier, not a declaration. Give nicer // errors for declaration-looking typos. if (!tokenStream.currentToken().nameContainsEscape() && tokenStream.currentName() == context->names().let) { bool forbiddenLetDeclaration = false; if (pc->sc()->strict() || versionNumber() >= JSVERSION_1_7) { // |let| can't be an Identifier in strict mode code. Ditto for // non-standard JavaScript 1.7+. forbiddenLetDeclaration = true; } else if (next == TOK_LB) { // Enforce ExpressionStatement's 'let [' lookahead restriction. forbiddenLetDeclaration = true; } else if (next == TOK_LC || next == TOK_NAME) { // 'let {' and 'let foo' aren't completely forbidden, if ASI // causes 'let' to be the entire Statement. But if they're // same-line, we can aggressively give a better error message. // // Note that this ignores 'yield' as TOK_YIELD: we'll handle it // correctly but with a worse error message. TokenKind nextSameLine; if (!tokenStream.peekTokenSameLine(&nextSameLine)) return null(); MOZ_ASSERT(nextSameLine == TOK_NAME || nextSameLine == TOK_LC || nextSameLine == TOK_EOL); forbiddenLetDeclaration = nextSameLine != TOK_EOL; } if (forbiddenLetDeclaration) { error(JSMSG_FORBIDDEN_AS_STATEMENT, "lexical declarations"); return null(); } } // NOTE: It's unfortunately allowed to have a label named 'let' in // non-strict code. 💯 if (next == TOK_COLON) return labeledStatement(yieldHandling); return expressionStatement(yieldHandling); } case TOK_NEW: return expressionStatement(yieldHandling, PredictInvoked); default: return expressionStatement(yieldHandling); // IfStatement[?Yield, ?Return] case TOK_IF: return ifStatement(yieldHandling); // BreakableStatement[?Yield, ?Return] // // BreakableStatement[Yield, Return]: // IterationStatement[?Yield, ?Return] // SwitchStatement[?Yield, ?Return] case TOK_DO: return doWhileStatement(yieldHandling); case TOK_WHILE: return whileStatement(yieldHandling); case TOK_FOR: return forStatement(yieldHandling); case TOK_SWITCH: return switchStatement(yieldHandling); // ContinueStatement[?Yield] case TOK_CONTINUE: return continueStatement(yieldHandling); // BreakStatement[?Yield] case TOK_BREAK: return breakStatement(yieldHandling); // [+Return] ReturnStatement[?Yield] case TOK_RETURN: // The Return parameter is only used here, and the effect is easily // detected this way, so don't bother passing around an extra parameter // everywhere. if (!pc->isFunctionBox()) { error(JSMSG_BAD_RETURN_OR_YIELD, js_return_str); return null(); } return returnStatement(yieldHandling); // WithStatement[?Yield, ?Return] case TOK_WITH: return withStatement(yieldHandling); // LabelledStatement[?Yield, ?Return] // This is really handled by TOK_NAME and TOK_YIELD cases above. // ThrowStatement[?Yield] case TOK_THROW: return throwStatement(yieldHandling); // TryStatement[?Yield, ?Return] case TOK_TRY: return tryStatement(yieldHandling); // DebuggerStatement case TOK_DEBUGGER: return debuggerStatement(); // |function| is forbidden by lookahead restriction (unless as child // statement of |if| or |else|, but Parser::consequentOrAlternative // handles that). case TOK_FUNCTION: error(JSMSG_FORBIDDEN_AS_STATEMENT, "function declarations"); return null(); // |class| is also forbidden by lookahead restriction. case TOK_CLASS: error(JSMSG_FORBIDDEN_AS_STATEMENT, "classes"); return null(); // ImportDeclaration (only inside modules) case TOK_IMPORT: return importDeclaration(); // ExportDeclaration (only inside modules) case TOK_EXPORT: return exportDeclaration(); // Miscellaneous error cases arguably better caught here than elsewhere. case TOK_CATCH: error(JSMSG_CATCH_WITHOUT_TRY); return null(); case TOK_FINALLY: error(JSMSG_FINALLY_WITHOUT_TRY); return null(); // NOTE: default case handled in the ExpressionStatement section. } } template typename ParseHandler::Node Parser::statementListItem(YieldHandling yieldHandling, bool canHaveDirectives /* = false */) { MOZ_ASSERT(checkOptionsCalled); JS_CHECK_RECURSION(context, return null()); TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); switch (tt) { // BlockStatement[?Yield, ?Return] case TOK_LC: return blockStatement(yieldHandling); // VariableStatement[?Yield] case TOK_VAR: return variableStatement(yieldHandling); // EmptyStatement case TOK_SEMI: return handler.newEmptyStatement(pos()); // ExpressionStatement[?Yield]. // // These should probably be handled by a single ExpressionStatement // function in a default, not split up this way. case TOK_STRING: if (!canHaveDirectives && tokenStream.currentToken().atom() == context->names().useAsm) { if (!abortIfSyntaxParser()) return null(); if (!warning(JSMSG_USE_ASM_DIRECTIVE_FAIL)) return null(); } return expressionStatement(yieldHandling); case TOK_YIELD: { // Don't use a ternary operator here due to obscure linker issues // around using static consts in the arms of a ternary. TokenStream::Modifier modifier; if (yieldExpressionsSupported()) modifier = TokenStream::Operand; else modifier = TokenStream::None; TokenKind next; if (!tokenStream.peekToken(&next, modifier)) return null(); if (next == TOK_COLON) return labeledStatement(yieldHandling); return expressionStatement(yieldHandling); } case TOK_NAME: { TokenKind next; if (!tokenStream.peekToken(&next)) return null(); if (!tokenStream.currentToken().nameContainsEscape() && tokenStream.currentName() == context->names().let && nextTokenContinuesLetDeclaration(next, yieldHandling)) { return lexicalDeclaration(yieldHandling, /* isConst = */ false); } if (tokenStream.currentName() == context->names().async) { TokenKind nextSameLine = TOK_EOF; if (!tokenStream.peekTokenSameLine(&nextSameLine)) return null(); if (nextSameLine == TOK_FUNCTION) { uint32_t preludeStart = pos().begin; tokenStream.consumeKnownToken(TOK_FUNCTION); return functionStmt(preludeStart, yieldHandling, NameRequired, AsyncFunction); } } if (next == TOK_COLON) return labeledStatement(yieldHandling); return expressionStatement(yieldHandling); } case TOK_NEW: return expressionStatement(yieldHandling, PredictInvoked); default: return expressionStatement(yieldHandling); // IfStatement[?Yield, ?Return] case TOK_IF: return ifStatement(yieldHandling); // BreakableStatement[?Yield, ?Return] // // BreakableStatement[Yield, Return]: // IterationStatement[?Yield, ?Return] // SwitchStatement[?Yield, ?Return] case TOK_DO: return doWhileStatement(yieldHandling); case TOK_WHILE: return whileStatement(yieldHandling); case TOK_FOR: return forStatement(yieldHandling); case TOK_SWITCH: return switchStatement(yieldHandling); // ContinueStatement[?Yield] case TOK_CONTINUE: return continueStatement(yieldHandling); // BreakStatement[?Yield] case TOK_BREAK: return breakStatement(yieldHandling); // [+Return] ReturnStatement[?Yield] case TOK_RETURN: // The Return parameter is only used here, and the effect is easily // detected this way, so don't bother passing around an extra parameter // everywhere. if (!pc->isFunctionBox()) { error(JSMSG_BAD_RETURN_OR_YIELD, js_return_str); return null(); } return returnStatement(yieldHandling); // WithStatement[?Yield, ?Return] case TOK_WITH: return withStatement(yieldHandling); // LabelledStatement[?Yield, ?Return] // This is really handled by TOK_NAME and TOK_YIELD cases above. // ThrowStatement[?Yield] case TOK_THROW: return throwStatement(yieldHandling); // TryStatement[?Yield, ?Return] case TOK_TRY: return tryStatement(yieldHandling); // DebuggerStatement case TOK_DEBUGGER: return debuggerStatement(); // Declaration[Yield]: // HoistableDeclaration[?Yield, ~Default] case TOK_FUNCTION: return functionStmt(pos().begin, yieldHandling, NameRequired); // ClassDeclaration[?Yield, ~Default] case TOK_CLASS: return classDefinition(yieldHandling, ClassStatement, NameRequired); // LexicalDeclaration[In, ?Yield] // LetOrConst BindingList[?In, ?Yield] case TOK_CONST: // [In] is the default behavior, because for-loops specially parse // their heads to handle |in| in this situation. return lexicalDeclaration(yieldHandling, /* isConst = */ true); // ImportDeclaration (only inside modules) case TOK_IMPORT: return importDeclaration(); // ExportDeclaration (only inside modules) case TOK_EXPORT: return exportDeclaration(); // Miscellaneous error cases arguably better caught here than elsewhere. case TOK_CATCH: error(JSMSG_CATCH_WITHOUT_TRY); return null(); case TOK_FINALLY: error(JSMSG_FINALLY_WITHOUT_TRY); return null(); // NOTE: default case handled in the ExpressionStatement section. } } template typename ParseHandler::Node Parser::expr(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError /* = nullptr */, InvokedPrediction invoked /* = PredictUninvoked */) { Node pn = assignExpr(inHandling, yieldHandling, tripledotHandling, possibleError, invoked); if (!pn) return null(); bool matched; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return null(); if (!matched) return pn; Node seq = handler.newCommaExpressionList(pn); if (!seq) return null(); while (true) { // Trailing comma before the closing parenthesis is valid in an arrow // function parameters list: `(a, b, ) => body`. Check if we are // directly under CoverParenthesizedExpressionAndArrowParameterList, // and the next two tokens are closing parenthesis and arrow. If all // are present allow the trailing comma. if (tripledotHandling == TripledotAllowed) { TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_RP) { tokenStream.consumeKnownToken(TOK_RP, TokenStream::Operand); if (!tokenStream.peekToken(&tt)) return null(); if (tt != TOK_ARROW) { error(JSMSG_UNEXPECTED_TOKEN, "expression", TokenKindToDesc(TOK_RP)); return null(); } tokenStream.ungetToken(); // put back right paren tokenStream.addModifierException(TokenStream::NoneIsOperand); break; } } // Additional calls to assignExpr should not reuse the possibleError // which had been passed into the function. Otherwise we would lose // information needed to determine whether or not we're dealing with // a non-recoverable situation. PossibleError possibleErrorInner(*this); pn = assignExpr(inHandling, yieldHandling, tripledotHandling, &possibleErrorInner); if (!pn) return null(); if (!possibleError) { // Report any pending expression error. if (!possibleErrorInner.checkForExpressionError()) return null(); } else { possibleErrorInner.transferErrorsTo(possibleError); } handler.addList(seq, pn); if (!tokenStream.matchToken(&matched, TOK_COMMA)) return null(); if (!matched) break; } return seq; } static const JSOp ParseNodeKindToJSOp[] = { JSOP_OR, JSOP_AND, JSOP_BITOR, JSOP_BITXOR, JSOP_BITAND, JSOP_STRICTEQ, JSOP_EQ, JSOP_STRICTNE, JSOP_NE, JSOP_LT, JSOP_LE, JSOP_GT, JSOP_GE, JSOP_INSTANCEOF, JSOP_IN, JSOP_LSH, JSOP_RSH, JSOP_URSH, JSOP_ADD, JSOP_SUB, JSOP_MUL, JSOP_DIV, JSOP_MOD, JSOP_POW }; static inline JSOp BinaryOpParseNodeKindToJSOp(ParseNodeKind pnk) { MOZ_ASSERT(pnk >= PNK_BINOP_FIRST); MOZ_ASSERT(pnk <= PNK_BINOP_LAST); return ParseNodeKindToJSOp[pnk - PNK_BINOP_FIRST]; } static ParseNodeKind BinaryOpTokenKindToParseNodeKind(TokenKind tok) { MOZ_ASSERT(TokenKindIsBinaryOp(tok)); return ParseNodeKind(PNK_BINOP_FIRST + (tok - TOK_BINOP_FIRST)); } static const int PrecedenceTable[] = { 1, /* PNK_OR */ 2, /* PNK_AND */ 3, /* PNK_BITOR */ 4, /* PNK_BITXOR */ 5, /* PNK_BITAND */ 6, /* PNK_STRICTEQ */ 6, /* PNK_EQ */ 6, /* PNK_STRICTNE */ 6, /* PNK_NE */ 7, /* PNK_LT */ 7, /* PNK_LE */ 7, /* PNK_GT */ 7, /* PNK_GE */ 7, /* PNK_INSTANCEOF */ 7, /* PNK_IN */ 8, /* PNK_LSH */ 8, /* PNK_RSH */ 8, /* PNK_URSH */ 9, /* PNK_ADD */ 9, /* PNK_SUB */ 10, /* PNK_STAR */ 10, /* PNK_DIV */ 10, /* PNK_MOD */ 11 /* PNK_POW */ }; static const int PRECEDENCE_CLASSES = 11; static int Precedence(ParseNodeKind pnk) { // Everything binds tighter than PNK_LIMIT, because we want to reduce all // nodes to a single node when we reach a token that is not another binary // operator. if (pnk == PNK_LIMIT) return 0; MOZ_ASSERT(pnk >= PNK_BINOP_FIRST); MOZ_ASSERT(pnk <= PNK_BINOP_LAST); return PrecedenceTable[pnk - PNK_BINOP_FIRST]; } template MOZ_ALWAYS_INLINE typename ParseHandler::Node Parser::orExpr1(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError, InvokedPrediction invoked /* = PredictUninvoked */) { // Shift-reduce parser for the binary operator part of the JS expression // syntax. // Conceptually there's just one stack, a stack of pairs (lhs, op). // It's implemented using two separate arrays, though. Node nodeStack[PRECEDENCE_CLASSES]; ParseNodeKind kindStack[PRECEDENCE_CLASSES]; int depth = 0; Node pn; for (;;) { pn = unaryExpr(yieldHandling, tripledotHandling, possibleError, invoked); if (!pn) return pn; // If a binary operator follows, consume it and compute the // corresponding operator. TokenKind tok; if (!tokenStream.getToken(&tok)) return null(); ParseNodeKind pnk; if (tok == TOK_IN ? inHandling == InAllowed : TokenKindIsBinaryOp(tok)) { // We're definitely not in a destructuring context, so report any // pending expression error now. if (possibleError && !possibleError->checkForExpressionError()) return null(); // Report an error for unary expressions on the LHS of **. if (tok == TOK_POW && handler.isUnparenthesizedUnaryExpression(pn)) { error(JSMSG_BAD_POW_LEFTSIDE); return null(); } pnk = BinaryOpTokenKindToParseNodeKind(tok); } else { tok = TOK_EOF; pnk = PNK_LIMIT; } // From this point on, destructuring defaults are definitely an error. possibleError = nullptr; // If pnk has precedence less than or equal to another operator on the // stack, reduce. This combines nodes on the stack until we form the // actual lhs of pnk. // // The >= in this condition works because it is appendOrCreateList's // job to decide if the operator in question is left- or // right-associative, and build the corresponding tree. while (depth > 0 && Precedence(kindStack[depth - 1]) >= Precedence(pnk)) { depth--; ParseNodeKind combiningPnk = kindStack[depth]; JSOp combiningOp = BinaryOpParseNodeKindToJSOp(combiningPnk); pn = handler.appendOrCreateList(combiningPnk, nodeStack[depth], pn, pc, combiningOp); if (!pn) return pn; } if (pnk == PNK_LIMIT) break; nodeStack[depth] = pn; kindStack[depth] = pnk; depth++; MOZ_ASSERT(depth <= PRECEDENCE_CLASSES); } MOZ_ASSERT(depth == 0); return pn; } template MOZ_ALWAYS_INLINE typename ParseHandler::Node Parser::condExpr1(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError, InvokedPrediction invoked /* = PredictUninvoked */) { Node condition = orExpr1(inHandling, yieldHandling, tripledotHandling, possibleError, invoked); if (!condition || !tokenStream.isCurrentTokenType(TOK_HOOK)) return condition; Node thenExpr = assignExpr(InAllowed, yieldHandling, TripledotProhibited); if (!thenExpr) return null(); MUST_MATCH_TOKEN(TOK_COLON, JSMSG_COLON_IN_COND); Node elseExpr = assignExpr(inHandling, yieldHandling, TripledotProhibited); if (!elseExpr) return null(); // Advance to the next token; the caller is responsible for interpreting it. TokenKind ignored; if (!tokenStream.getToken(&ignored)) return null(); return handler.newConditional(condition, thenExpr, elseExpr); } class AutoClearInDestructuringDecl { ParseContext* pc_; Maybe saved_; public: explicit AutoClearInDestructuringDecl(ParseContext* pc) : pc_(pc), saved_(pc->inDestructuringDecl) { pc->inDestructuringDecl = Nothing(); if (saved_ && *saved_ == DeclarationKind::FormalParameter) pc->functionBox()->hasParameterExprs = true; } ~AutoClearInDestructuringDecl() { pc_->inDestructuringDecl = saved_; } }; template typename ParseHandler::Node Parser::assignExpr(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError /* = nullptr */, InvokedPrediction invoked /* = PredictUninvoked */) { JS_CHECK_RECURSION(context, return null()); // It's very common at this point to have a "detectably simple" expression, // i.e. a name/number/string token followed by one of the following tokens // that obviously isn't part of an expression: , ; : ) ] } // // (In Parsemark this happens 81.4% of the time; in code with large // numeric arrays, such as some Kraken benchmarks, it happens more often.) // // In such cases, we can avoid the full expression parsing route through // assignExpr(), condExpr1(), orExpr1(), unaryExpr(), memberExpr(), and // primaryExpr(). TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); uint32_t exprOffset = pos().begin; bool endsExpr; if (tt == TOK_NAME) { if (!tokenStream.nextTokenEndsExpr(&endsExpr)) return null(); if (endsExpr) { Rooted name(context, identifierReference(yieldHandling)); if (!name) return null(); return identifierReference(name); } } if (tt == TOK_NUMBER) { if (!tokenStream.nextTokenEndsExpr(&endsExpr)) return null(); if (endsExpr) return newNumber(tokenStream.currentToken()); } if (tt == TOK_STRING) { if (!tokenStream.nextTokenEndsExpr(&endsExpr)) return null(); if (endsExpr) return stringLiteral(); } if (tt == TOK_YIELD && yieldExpressionsSupported()) return yieldExpression(inHandling); bool maybeAsyncArrow = false; if (tt == TOK_NAME && tokenStream.currentName() == context->names().async) { TokenKind nextSameLine = TOK_EOF; if (!tokenStream.peekTokenSameLine(&nextSameLine)) return null(); if (nextSameLine == TOK_NAME || nextSameLine == TOK_YIELD) maybeAsyncArrow = true; } tokenStream.ungetToken(); // Save the tokenizer state in case we find an arrow function and have to // rewind. TokenStream::Position start(keepAtoms); tokenStream.tell(&start); PossibleError possibleErrorInner(*this); Node lhs; if (maybeAsyncArrow) { tokenStream.consumeKnownToken(TOK_NAME, TokenStream::Operand); MOZ_ASSERT(tokenStream.currentName() == context->names().async); TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); MOZ_ASSERT(tt == TOK_NAME || tt == TOK_YIELD); // Check yield validity here. RootedPropertyName name(context, bindingIdentifier(yieldHandling)); if (!name) return null(); if (!tokenStream.getToken(&tt)) return null(); if (tt != TOK_ARROW) { error(JSMSG_UNEXPECTED_TOKEN, "'=>' after argument list", TokenKindToDesc(tt)); return null(); } } else { lhs = condExpr1(inHandling, yieldHandling, tripledotHandling, &possibleErrorInner, invoked); if (!lhs) { return null(); } } ParseNodeKind kind; JSOp op; switch (tokenStream.currentToken().type) { case TOK_ASSIGN: kind = PNK_ASSIGN; op = JSOP_NOP; break; case TOK_ADDASSIGN: kind = PNK_ADDASSIGN; op = JSOP_ADD; break; case TOK_SUBASSIGN: kind = PNK_SUBASSIGN; op = JSOP_SUB; break; case TOK_BITORASSIGN: kind = PNK_BITORASSIGN; op = JSOP_BITOR; break; case TOK_BITXORASSIGN: kind = PNK_BITXORASSIGN; op = JSOP_BITXOR; break; case TOK_BITANDASSIGN: kind = PNK_BITANDASSIGN; op = JSOP_BITAND; break; case TOK_LSHASSIGN: kind = PNK_LSHASSIGN; op = JSOP_LSH; break; case TOK_RSHASSIGN: kind = PNK_RSHASSIGN; op = JSOP_RSH; break; case TOK_URSHASSIGN: kind = PNK_URSHASSIGN; op = JSOP_URSH; break; case TOK_MULASSIGN: kind = PNK_MULASSIGN; op = JSOP_MUL; break; case TOK_DIVASSIGN: kind = PNK_DIVASSIGN; op = JSOP_DIV; break; case TOK_MODASSIGN: kind = PNK_MODASSIGN; op = JSOP_MOD; break; case TOK_POWASSIGN: kind = PNK_POWASSIGN; op = JSOP_POW; break; case TOK_ARROW: { // A line terminator between ArrowParameters and the => should trigger a SyntaxError. tokenStream.ungetToken(); TokenKind next; if (!tokenStream.peekTokenSameLine(&next)) return null(); MOZ_ASSERT(next == TOK_ARROW || next == TOK_EOL); if (next != TOK_ARROW) { error(JSMSG_LINE_BREAK_BEFORE_ARROW); return null(); } tokenStream.consumeKnownToken(TOK_ARROW); bool isBlock = false; if (!tokenStream.peekToken(&next, TokenStream::Operand)) return null(); if (next == TOK_LC) isBlock = true; tokenStream.seek(start); if (!tokenStream.getToken(&next, TokenStream::Operand)) return null(); uint32_t preludeStart = pos().begin; tokenStream.ungetToken(); GeneratorKind generatorKind = NotGenerator; FunctionAsyncKind asyncKind = SyncFunction; if (next == TOK_NAME) { tokenStream.consumeKnownToken(next, TokenStream::Operand); if (tokenStream.currentName() == context->names().async) { TokenKind nextSameLine = TOK_EOF; if (!tokenStream.peekTokenSameLine(&nextSameLine)) return null(); if (nextSameLine == TOK_ARROW) { tokenStream.ungetToken(); } else { generatorKind = StarGenerator; asyncKind = AsyncFunction; } } else { tokenStream.ungetToken(); } } Node pn = handler.newArrowFunction(); if (!pn) return null(); Node arrowFunc = functionDefinition(preludeStart, pn, inHandling, yieldHandling, nullptr, Arrow, generatorKind, asyncKind); if (!arrowFunc) return null(); if (isBlock) { // This arrow function could be a non-trailing member of a comma // expression or a semicolon terminating a full expression. If so, // the next token is that comma/semicolon, gotten with None: // // a => {}, b; // as if (a => {}), b; // a => {}; // // But if this arrow function ends a statement, ASI permits the // next token to start an expression statement. In that case the // next token must be gotten as Operand: // // a => {} // complete expression statement // /x/g; // regular expression as a statement, *not* division // // Getting the second case right requires the first token-peek // after the arrow function use Operand, and that peek must occur // before Parser::expr() looks for a comma. Do so here, then // immediately add the modifier exception needed for the first // case. // // Note that the second case occurs *only* if the arrow function // has block body. An arrow function not ending in such, ends in // another AssignmentExpression that we can inductively assume was // peeked consistently. TokenKind ignored; if (!tokenStream.peekToken(&ignored, TokenStream::Operand)) return null(); tokenStream.addModifierException(TokenStream::NoneIsOperand); } return arrowFunc; } default: MOZ_ASSERT(!tokenStream.isCurrentTokenAssignment()); if (!possibleError) { if (!possibleErrorInner.checkForExpressionError()) return null(); } else { possibleErrorInner.transferErrorsTo(possibleError); } tokenStream.ungetToken(); return lhs; } // Verify the left-hand side expression doesn't have a forbidden form. if (handler.isUnparenthesizedDestructuringPattern(lhs)) { if (kind != PNK_ASSIGN) { error(JSMSG_BAD_DESTRUCT_ASS); return null(); } if (!checkDestructuringPattern(lhs, Nothing(), &possibleErrorInner)) return null(); } else if (handler.isNameAnyParentheses(lhs)) { if (const char* chars = handler.nameIsArgumentsEvalAnyParentheses(lhs, context)) { // |chars| is "arguments" or "eval" here. if (!strictModeErrorAt(exprOffset, JSMSG_BAD_STRICT_ASSIGN, chars)) return null(); } handler.adjustGetToSet(lhs); } else if (handler.isPropertyAccess(lhs)) { // Permitted: no additional testing/fixup needed. } else if (handler.isFunctionCall(lhs)) { if (!strictModeErrorAt(exprOffset, JSMSG_BAD_LEFTSIDE_OF_ASS)) return null(); } else { errorAt(exprOffset, JSMSG_BAD_LEFTSIDE_OF_ASS); return null(); } if (!possibleErrorInner.checkForExpressionError()) return null(); Node rhs; { AutoClearInDestructuringDecl autoClear(pc); rhs = assignExpr(inHandling, yieldHandling, TripledotProhibited); if (!rhs) return null(); } if (kind == PNK_ASSIGN) handler.checkAndSetIsDirectRHSAnonFunction(rhs); return handler.newAssignment(kind, lhs, rhs, op); } template bool Parser::isValidSimpleAssignmentTarget(Node node, FunctionCallBehavior behavior /* = ForbidAssignmentToFunctionCalls */) { // Note that this method implements *only* a boolean test. Reporting an // error for the various syntaxes that fail this, and warning for the // various syntaxes that "pass" this but should not, occurs elsewhere. if (handler.isNameAnyParentheses(node)) { if (!pc->sc()->strict()) return true; return !handler.nameIsArgumentsEvalAnyParentheses(node, context); } if (handler.isPropertyAccess(node)) return true; if (behavior == PermitAssignmentToFunctionCalls) { if (handler.isFunctionCall(node)) return true; } return false; } template bool Parser::checkIncDecOperand(Node operand, uint32_t operandOffset) { if (handler.isNameAnyParentheses(operand)) { if (const char* chars = handler.nameIsArgumentsEvalAnyParentheses(operand, context)) { if (!strictModeErrorAt(operandOffset, JSMSG_BAD_STRICT_ASSIGN, chars)) return false; } } else if (handler.isPropertyAccess(operand)) { // Permitted: no additional testing/fixup needed. } else if (handler.isFunctionCall(operand)) { // Assignment to function calls is forbidden in ES6. We're still // somewhat concerned about sites using this in dead code, so forbid it // only in strict mode code (or if the werror option has been set), and // otherwise warn. if (!strictModeErrorAt(operandOffset, JSMSG_BAD_INCOP_OPERAND)) return false; } else { errorAt(operandOffset, JSMSG_BAD_INCOP_OPERAND); return false; } MOZ_ASSERT(isValidSimpleAssignmentTarget(operand, PermitAssignmentToFunctionCalls), "inconsistent increment/decrement operand validation"); return true; } template typename ParseHandler::Node Parser::unaryOpExpr(YieldHandling yieldHandling, ParseNodeKind kind, JSOp op, uint32_t begin) { Node kid = unaryExpr(yieldHandling, TripledotProhibited); if (!kid) return null(); return handler.newUnary(kind, op, begin, kid); } template typename ParseHandler::Node Parser::unaryExpr(YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError /* = nullptr */, InvokedPrediction invoked /* = PredictUninvoked */) { JS_CHECK_RECURSION(context, return null()); TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); uint32_t begin = pos().begin; switch (tt) { case TOK_VOID: return unaryOpExpr(yieldHandling, PNK_VOID, JSOP_VOID, begin); case TOK_NOT: return unaryOpExpr(yieldHandling, PNK_NOT, JSOP_NOT, begin); case TOK_BITNOT: return unaryOpExpr(yieldHandling, PNK_BITNOT, JSOP_BITNOT, begin); case TOK_ADD: return unaryOpExpr(yieldHandling, PNK_POS, JSOP_POS, begin); case TOK_SUB: return unaryOpExpr(yieldHandling, PNK_NEG, JSOP_NEG, begin); case TOK_TYPEOF: { // The |typeof| operator is specially parsed to distinguish its // application to a name, from its application to a non-name // expression: // // // Looks up the name, doesn't find it and so evaluates to // // "undefined". // assertEq(typeof nonExistentName, "undefined"); // // // Evaluates expression, triggering a runtime ReferenceError for // // the undefined name. // typeof (1, nonExistentName); Node kid = unaryExpr(yieldHandling, TripledotProhibited); if (!kid) return null(); return handler.newTypeof(begin, kid); } case TOK_INC: case TOK_DEC: { TokenKind tt2; if (!tokenStream.getToken(&tt2, TokenStream::Operand)) return null(); uint32_t operandOffset = pos().begin; Node operand = memberExpr(yieldHandling, TripledotProhibited, tt2); if (!operand || !checkIncDecOperand(operand, operandOffset)) return null(); return handler.newUpdate((tt == TOK_INC) ? PNK_PREINCREMENT : PNK_PREDECREMENT, begin, operand); } case TOK_DELETE: { uint32_t exprOffset; if (!tokenStream.peekOffset(&exprOffset, TokenStream::Operand)) return null(); Node expr = unaryExpr(yieldHandling, TripledotProhibited); if (!expr) return null(); // Per spec, deleting any unary expression is valid -- it simply // returns true -- except for one case that is illegal in strict mode. if (handler.isNameAnyParentheses(expr)) { if (!strictModeErrorAt(exprOffset, JSMSG_DEPRECATED_DELETE_OPERAND)) return null(); pc->sc()->setBindingsAccessedDynamically(); } return handler.newDelete(begin, expr); } case TOK_AWAIT: { if (!pc->isAsync()) { // TOK_AWAIT can be returned in module, even if it's not inside // async function. error(JSMSG_RESERVED_ID, "await"); return null(); } Node kid = unaryExpr(yieldHandling, tripledotHandling, possibleError, invoked); if (!kid) return null(); pc->lastAwaitOffset = begin; return newAwaitExpression(begin, kid); } default: { Node expr = memberExpr(yieldHandling, tripledotHandling, tt, /* allowCallSyntax = */ true, possibleError, invoked); if (!expr) return null(); /* Don't look across a newline boundary for a postfix incop. */ if (!tokenStream.peekTokenSameLine(&tt)) return null(); if (tt != TOK_INC && tt != TOK_DEC) return expr; tokenStream.consumeKnownToken(tt); if (!checkIncDecOperand(expr, begin)) return null(); return handler.newUpdate((tt == TOK_INC) ? PNK_POSTINCREMENT : PNK_POSTDECREMENT, begin, expr); } } } /*** Comprehensions ******************************************************************************* * * We currently support two flavors of comprehensions, all deprecated: * * [for (V of OBJ) if (COND) EXPR] // ES6-era array comprehension * (for (V of OBJ) if (COND) EXPR) // ES6-era generator expression * * (These flavors are called "ES6-era" because they were in ES6 draft * specifications for a while. Shortly after this syntax was implemented in SM, * TC39 decided to drop it.) */ template typename ParseHandler::Node Parser::generatorComprehensionLambda(unsigned begin) { Node genfn = handler.newFunctionExpression(); if (!genfn) return null(); ParseContext* outerpc = pc; // If we are off the main thread, the generator meta-objects have // already been created by js::StartOffThreadParseScript, so cx will not // be necessary. RootedObject proto(context); JSContext* cx = context->maybeJSContext(); proto = GlobalObject::getOrCreateStarGeneratorFunctionPrototype(cx, context->global()); if (!proto) return null(); RootedFunction fun(context, newFunction(/* atom = */ nullptr, Expression, StarGenerator, SyncFunction, proto)); if (!fun) return null(); // Create box for fun->object early to root it. Directives directives(/* strict = */ outerpc->sc()->strict()); FunctionBox* genFunbox = newFunctionBox(genfn, fun, /* preludeStart = */ 0, directives, StarGenerator, SyncFunction, /* tryAnnexB = */ false); if (!genFunbox) return null(); genFunbox->isGenexpLambda = true; genFunbox->initWithEnclosingParseContext(outerpc, Expression); ParseContext genpc(this, genFunbox, /* newDirectives = */ nullptr); if (!genpc.init()) return null(); genpc.functionScope().useAsVarScope(&genpc); /* * We assume conservatively that any deoptimization flags in pc->sc() * come from the kid. So we propagate these flags into genfn. For code * simplicity we also do not detect if the flags were only set in the * kid and could be removed from pc->sc(). */ genFunbox->anyCxFlags = outerpc->sc()->anyCxFlags; if (!declareDotGeneratorName()) return null(); Node body = handler.newStatementList(TokenPos(begin, pos().end)); if (!body) return null(); Node comp = comprehension(StarGenerator); if (!comp) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_IN_PAREN); uint32_t end = pos().end; handler.setBeginPosition(comp, begin); handler.setEndPosition(comp, end); genFunbox->bufEnd = end; handler.addStatementToList(body, comp); handler.setEndPosition(body, end); handler.setBeginPosition(genfn, begin); handler.setEndPosition(genfn, end); Node generator = newDotGeneratorName(); if (!generator) return null(); if (!handler.prependInitialYield(body, generator)) return null(); if (!propagateFreeNamesAndMarkClosedOverBindings(pc->varScope())) return null(); if (!finishFunction()) return null(); if (!leaveInnerFunction(outerpc)) return null(); // Note that if we ever start syntax-parsing generators, we will also // need to propagate the closed-over variable set to the inner // lazyscript. if (!handler.setComprehensionLambdaBody(genfn, body)) return null(); return genfn; } template typename ParseHandler::Node Parser::comprehensionFor(GeneratorKind comprehensionKind) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_FOR)); uint32_t begin = pos().begin; MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_AFTER_FOR); // FIXME: Destructuring binding (bug 980828). MUST_MATCH_TOKEN(TOK_NAME, JSMSG_NO_VARIABLE_NAME); RootedPropertyName name(context, tokenStream.currentName()); if (name == context->names().let) { error(JSMSG_LET_COMP_BINDING); return null(); } TokenPos namePos = pos(); Node lhs = newName(name); if (!lhs) return null(); bool matched; if (!tokenStream.matchContextualKeyword(&matched, context->names().of)) return null(); if (!matched) { error(JSMSG_OF_AFTER_FOR_NAME); return null(); } Node rhs = assignExpr(InAllowed, YieldIsKeyword, TripledotProhibited); if (!rhs) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_FOR_OF_ITERABLE); TokenPos headPos(begin, pos().end); ParseContext::Scope scope(this); if (!scope.init(pc)) return null(); { // Push a temporary ForLoopLexicalHead Statement that allows for // lexical declarations, as they are usually allowed only in braced // statements. ParseContext::Statement forHeadStmt(pc, StatementKind::ForLoopLexicalHead); if (!noteDeclaredName(name, DeclarationKind::Let, namePos)) return null(); } Node decls = handler.newComprehensionBinding(lhs); if (!decls) return null(); Node tail = comprehensionTail(comprehensionKind); if (!tail) return null(); // Finish the lexical scope after parsing the tail. Node lexicalScope = finishLexicalScope(scope, decls); if (!lexicalScope) return null(); Node head = handler.newForInOrOfHead(PNK_FOROF, lexicalScope, rhs, headPos); if (!head) return null(); return handler.newComprehensionFor(begin, head, tail); } template typename ParseHandler::Node Parser::comprehensionIf(GeneratorKind comprehensionKind) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_IF)); uint32_t begin = pos().begin; MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_COND); Node cond = assignExpr(InAllowed, YieldIsKeyword, TripledotProhibited); if (!cond) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_COND); /* Check for (a = b) and warn about possible (a == b) mistype. */ if (handler.isUnparenthesizedAssignment(cond)) { if (!extraWarning(JSMSG_EQUAL_AS_ASSIGN)) return null(); } Node then = comprehensionTail(comprehensionKind); if (!then) return null(); return handler.newIfStatement(begin, cond, then, null()); } template typename ParseHandler::Node Parser::comprehensionTail(GeneratorKind comprehensionKind) { JS_CHECK_RECURSION(context, return null()); bool matched; if (!tokenStream.matchToken(&matched, TOK_FOR, TokenStream::Operand)) return null(); if (matched) return comprehensionFor(comprehensionKind); if (!tokenStream.matchToken(&matched, TOK_IF, TokenStream::Operand)) return null(); if (matched) return comprehensionIf(comprehensionKind); uint32_t begin = pos().begin; Node bodyExpr = assignExpr(InAllowed, YieldIsKeyword, TripledotProhibited); if (!bodyExpr) return null(); if (comprehensionKind == NotGenerator) return handler.newArrayPush(begin, bodyExpr); MOZ_ASSERT(comprehensionKind == StarGenerator); Node yieldExpr = newYieldExpression(begin, bodyExpr); if (!yieldExpr) return null(); yieldExpr = handler.parenthesize(yieldExpr); return handler.newExprStatement(yieldExpr, pos().end); } // Parse an ES6-era generator or array comprehension, starting at the first // `for`. The caller is responsible for matching the ending TOK_RP or TOK_RB. template typename ParseHandler::Node Parser::comprehension(GeneratorKind comprehensionKind) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_FOR)); uint32_t startYieldOffset = pc->lastYieldOffset; Node body = comprehensionFor(comprehensionKind); if (!body) return null(); if (comprehensionKind != NotGenerator && pc->lastYieldOffset != startYieldOffset) { errorAt(pc->lastYieldOffset, JSMSG_BAD_GENEXP_BODY, js_yield_str); return null(); } return body; } template typename ParseHandler::Node Parser::arrayComprehension(uint32_t begin) { Node inner = comprehension(NotGenerator); if (!inner) return null(); MUST_MATCH_TOKEN(TOK_RB, JSMSG_BRACKET_AFTER_ARRAY_COMPREHENSION); Node comp = handler.newList(PNK_ARRAYCOMP, inner); if (!comp) return null(); handler.setBeginPosition(comp, begin); handler.setEndPosition(comp, pos().end); return comp; } template typename ParseHandler::Node Parser::generatorComprehension(uint32_t begin) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_FOR)); // We have no problem parsing generator comprehensions inside lazy // functions, but the bytecode emitter currently can't handle them that way, // because when it goes to emit the code for the inner generator function, // it expects outer functions to have non-lazy scripts. if (!abortIfSyntaxParser()) return null(); Node genfn = generatorComprehensionLambda(begin); if (!genfn) return null(); Node result = handler.newList(PNK_GENEXP, genfn, JSOP_CALL); if (!result) return null(); handler.setBeginPosition(result, begin); handler.setEndPosition(result, pos().end); return result; } template typename ParseHandler::Node Parser::assignExprWithoutYieldOrAwait(YieldHandling yieldHandling) { uint32_t startYieldOffset = pc->lastYieldOffset; uint32_t startAwaitOffset = pc->lastAwaitOffset; Node res = assignExpr(InAllowed, yieldHandling, TripledotProhibited); if (res) { if (pc->lastYieldOffset != startYieldOffset) { errorAt(pc->lastYieldOffset, JSMSG_YIELD_IN_DEFAULT); return null(); } if (pc->lastAwaitOffset != startAwaitOffset) { errorAt(pc->lastAwaitOffset, JSMSG_AWAIT_IN_DEFAULT); return null(); } } return res; } template bool Parser::argumentList(YieldHandling yieldHandling, Node listNode, bool* isSpread, PossibleError* possibleError /* = nullptr */) { bool matched; if (!tokenStream.matchToken(&matched, TOK_RP, TokenStream::Operand)) return false; if (matched) { handler.setEndPosition(listNode, pos().end); return true; } while (true) { bool spread = false; uint32_t begin = 0; if (!tokenStream.matchToken(&matched, TOK_TRIPLEDOT, TokenStream::Operand)) return false; if (matched) { spread = true; begin = pos().begin; *isSpread = true; } Node argNode = assignExpr(InAllowed, yieldHandling, TripledotProhibited, possibleError); if (!argNode) return false; if (spread) { argNode = handler.newSpread(begin, argNode); if (!argNode) return false; } handler.addList(listNode, argNode); bool matched; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return false; if (!matched) break; TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_RP) { tokenStream.addModifierException(TokenStream::NoneIsOperand); break; } } MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_ARGS); handler.setEndPosition(listNode, pos().end); return true; } template bool Parser::checkAndMarkSuperScope() { if (!pc->sc()->allowSuperProperty()) return false; pc->setSuperScopeNeedsHomeObject(); return true; } template typename ParseHandler::Node Parser::memberExpr(YieldHandling yieldHandling, TripledotHandling tripledotHandling, TokenKind tt, bool allowCallSyntax /* = true */, PossibleError* possibleError /* = nullptr */, InvokedPrediction invoked /* = PredictUninvoked */) { MOZ_ASSERT(tokenStream.isCurrentTokenType(tt)); Node lhs; JS_CHECK_RECURSION(context, return null()); /* Check for new expression first. */ if (tt == TOK_NEW) { uint32_t newBegin = pos().begin; // Make sure this wasn't a |new.target| in disguise. Node newTarget; if (!tryNewTarget(newTarget)) return null(); if (newTarget) { lhs = newTarget; } else { lhs = handler.newList(PNK_NEW, newBegin, JSOP_NEW); if (!lhs) return null(); // Gotten by tryNewTarget tt = tokenStream.currentToken().type; Node ctorExpr = memberExpr(yieldHandling, TripledotProhibited, tt, /* allowCallSyntax = */ false, /* possibleError = */ nullptr, PredictInvoked); if (!ctorExpr) return null(); handler.addList(lhs, ctorExpr); bool matched; if (!tokenStream.matchToken(&matched, TOK_LP)) return null(); if (matched) { bool isSpread = false; if (!argumentList(yieldHandling, lhs, &isSpread)) return null(); if (isSpread) handler.setOp(lhs, JSOP_SPREADNEW); } } } else if (tt == TOK_SUPER) { Node thisName = newThisName(); if (!thisName) return null(); lhs = handler.newSuperBase(thisName, pos()); if (!lhs) return null(); } else { lhs = primaryExpr(yieldHandling, tripledotHandling, tt, possibleError, invoked); if (!lhs) return null(); } MOZ_ASSERT_IF(handler.isSuperBase(lhs), tokenStream.isCurrentTokenType(TOK_SUPER)); while (true) { if (!tokenStream.getToken(&tt)) return null(); if (tt == TOK_EOF) break; Node nextMember; if (tt == TOK_DOT) { if (!tokenStream.getToken(&tt, TokenStream::KeywordIsName)) return null(); if (tt == TOK_NAME) { PropertyName* field = tokenStream.currentName(); if (handler.isSuperBase(lhs) && !checkAndMarkSuperScope()) { error(JSMSG_BAD_SUPERPROP, "property"); return null(); } nextMember = handler.newPropertyAccess(lhs, field, pos().end); if (!nextMember) return null(); } else { error(JSMSG_NAME_AFTER_DOT); return null(); } } else if (tt == TOK_LB) { Node propExpr = expr(InAllowed, yieldHandling, TripledotProhibited); if (!propExpr) return null(); MUST_MATCH_TOKEN(TOK_RB, JSMSG_BRACKET_IN_INDEX); if (handler.isSuperBase(lhs) && !checkAndMarkSuperScope()) { error(JSMSG_BAD_SUPERPROP, "member"); return null(); } nextMember = handler.newPropertyByValue(lhs, propExpr, pos().end); if (!nextMember) return null(); } else if ((allowCallSyntax && tt == TOK_LP) || tt == TOK_TEMPLATE_HEAD || tt == TOK_NO_SUBS_TEMPLATE) { if (handler.isSuperBase(lhs)) { if (!pc->sc()->allowSuperCall()) { error(JSMSG_BAD_SUPERCALL); return null(); } if (tt != TOK_LP) { error(JSMSG_BAD_SUPER); return null(); } nextMember = handler.newList(PNK_SUPERCALL, lhs, JSOP_SUPERCALL); if (!nextMember) return null(); // Despite the fact that it's impossible to have |super()| in a // generator, we still inherit the yieldHandling of the // memberExpression, per spec. Curious. bool isSpread = false; if (!argumentList(yieldHandling, nextMember, &isSpread)) return null(); if (isSpread) handler.setOp(nextMember, JSOP_SPREADSUPERCALL); Node thisName = newThisName(); if (!thisName) return null(); nextMember = handler.newSetThis(thisName, nextMember); if (!nextMember) return null(); } else { if (options().selfHostingMode && handler.isPropertyAccess(lhs)) { error(JSMSG_SELFHOSTED_METHOD_CALL); return null(); } nextMember = tt == TOK_LP ? handler.newCall() : handler.newTaggedTemplate(); if (!nextMember) return null(); JSOp op = JSOP_CALL; bool maybeAsyncArrow = false; if (tt == TOK_LP && handler.isNameAnyParentheses(lhs)) { if (handler.nameIsEvalAnyParentheses(lhs, context)) { // Select the right EVAL op and flag pc as having a // direct eval. op = pc->sc()->strict() ? JSOP_STRICTEVAL : JSOP_EVAL; pc->sc()->setBindingsAccessedDynamically(); pc->sc()->setHasDirectEval(); // In non-strict mode code, direct calls to eval can // add variables to the call object. if (pc->isFunctionBox() && !pc->sc()->strict()) pc->functionBox()->setHasExtensibleScope(); // If we're in a method, mark the method as requiring // support for 'super', since direct eval code can use // it. (If we're not in a method, that's fine, so // ignore the return value.) checkAndMarkSuperScope(); } else if (handler.nameIsUnparenthesizedAsync(lhs, context)) { // |async (| can be the start of an async arrow // function, so we need to defer reporting possible // errors from destructuring syntax. To give better // error messages, we only allow the AsyncArrowHead // part of the CoverCallExpressionAndAsyncArrowHead // syntax when the initial name is "async". maybeAsyncArrow = true; } } else if (PropertyName* prop = handler.maybeDottedProperty(lhs)) { // Use the JSOP_FUN{APPLY,CALL} optimizations given the // right syntax. if (prop == context->names().apply) { op = JSOP_FUNAPPLY; if (pc->isFunctionBox()) pc->functionBox()->usesApply = true; } else if (prop == context->names().call) { op = JSOP_FUNCALL; } } handler.setBeginPosition(nextMember, lhs); handler.addList(nextMember, lhs); if (tt == TOK_LP) { bool isSpread = false; PossibleError* asyncPossibleError = maybeAsyncArrow ? possibleError : nullptr; if (!argumentList(yieldHandling, nextMember, &isSpread, asyncPossibleError)) return null(); if (isSpread) { if (op == JSOP_EVAL) op = JSOP_SPREADEVAL; else if (op == JSOP_STRICTEVAL) op = JSOP_STRICTSPREADEVAL; else op = JSOP_SPREADCALL; } } else { if (!taggedTemplate(yieldHandling, nextMember, tt)) return null(); } handler.setOp(nextMember, op); } } else { tokenStream.ungetToken(); if (handler.isSuperBase(lhs)) break; return lhs; } lhs = nextMember; } if (handler.isSuperBase(lhs)) { error(JSMSG_BAD_SUPER); return null(); } return lhs; } template typename ParseHandler::Node Parser::newName(PropertyName* name) { return newName(name, pos()); } template typename ParseHandler::Node Parser::newName(PropertyName* name, TokenPos pos) { return handler.newName(name, pos, context); } template PropertyName* Parser::labelOrIdentifierReference(YieldHandling yieldHandling, bool yieldTokenizedAsName) { PropertyName* ident; bool isYield; const Token& tok = tokenStream.currentToken(); if (tok.type == TOK_NAME) { MOZ_ASSERT(tok.name() != context->names().yield || tok.nameContainsEscape() || yieldTokenizedAsName, "tokenizer should have treated unescaped 'yield' as TOK_YIELD"); MOZ_ASSERT_IF(yieldTokenizedAsName, tok.name() == context->names().yield); ident = tok.name(); isYield = ident == context->names().yield; } else { MOZ_ASSERT(tok.type == TOK_YIELD && !yieldTokenizedAsName); ident = context->names().yield; isYield = true; } if (!isYield) { if (pc->sc()->strict()) { const char* badName = ident == context->names().let ? "let" : ident == context->names().static_ ? "static" : nullptr; if (badName) { error(JSMSG_RESERVED_ID, badName); return nullptr; } } } else { if (yieldHandling == YieldIsKeyword || pc->sc()->strict() || versionNumber() >= JSVERSION_1_7) { error(JSMSG_RESERVED_ID, "yield"); return nullptr; } } return ident; } template PropertyName* Parser::bindingIdentifier(YieldHandling yieldHandling) { PropertyName* ident; bool isYield; const Token& tok = tokenStream.currentToken(); if (tok.type == TOK_NAME) { MOZ_ASSERT(tok.name() != context->names().yield || tok.nameContainsEscape(), "tokenizer should have treated unescaped 'yield' as TOK_YIELD"); ident = tok.name(); isYield = ident == context->names().yield; } else { MOZ_ASSERT(tok.type == TOK_YIELD); ident = context->names().yield; isYield = true; } if (!isYield) { if (pc->sc()->strict()) { const char* badName = ident == context->names().arguments ? "arguments" : ident == context->names().eval ? "eval" : nullptr; if (badName) { error(JSMSG_BAD_STRICT_ASSIGN, badName); return nullptr; } badName = ident == context->names().let ? "let" : ident == context->names().static_ ? "static" : nullptr; if (badName) { error(JSMSG_RESERVED_ID, badName); return nullptr; } } } else { if (yieldHandling == YieldIsKeyword || pc->sc()->strict() || versionNumber() >= JSVERSION_1_7) { error(JSMSG_RESERVED_ID, "yield"); return nullptr; } } return ident; } template typename ParseHandler::Node Parser::identifierReference(Handle name) { Node pn = newName(name); if (!pn) return null(); if (!pc->inDestructuringDecl && !noteUsedName(name)) return null(); return pn; } template typename ParseHandler::Node Parser::stringLiteral() { return handler.newStringLiteral(stopStringCompression(), pos()); } template typename ParseHandler::Node Parser::noSubstitutionTemplate() { return handler.newTemplateStringLiteral(stopStringCompression(), pos()); } template JSAtom * Parser::stopStringCompression() { JSAtom* atom = tokenStream.currentToken().atom(); // Large strings are fast to parse but slow to compress. Stop compression on // them, so we don't wait for a long time for compression to finish at the // end of compilation. const size_t HUGE_STRING = 50000; if (sct && sct->active() && atom->length() >= HUGE_STRING) sct->abort(); return atom; } template typename ParseHandler::Node Parser::newRegExp() { MOZ_ASSERT(!options().selfHostingMode); // Create the regexp even when doing a syntax parse, to check the regexp's syntax. const char16_t* chars = tokenStream.getTokenbuf().begin(); size_t length = tokenStream.getTokenbuf().length(); RegExpFlag flags = tokenStream.currentToken().regExpFlags(); Rooted reobj(context); reobj = RegExpObject::create(context, chars, length, flags, &tokenStream, alloc); if (!reobj) return null(); return handler.newRegExp(reobj, pos(), *this); } template typename ParseHandler::Node Parser::arrayInitializer(YieldHandling yieldHandling, PossibleError* possibleError) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LB)); uint32_t begin = pos().begin; Node literal = handler.newArrayLiteral(begin); if (!literal) return null(); TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::Operand)) return null(); // Handle an ES6-era array comprehension first. if (tt == TOK_FOR) return arrayComprehension(begin); if (tt == TOK_RB) { /* * Mark empty arrays as non-constant, since we cannot easily * determine their type. */ handler.setListFlag(literal, PNX_NONCONST); } else { tokenStream.ungetToken(); uint32_t index = 0; TokenStream::Modifier modifier = TokenStream::Operand; for (; ; index++) { if (index >= NativeObject::MAX_DENSE_ELEMENTS_COUNT) { error(JSMSG_ARRAY_INIT_TOO_BIG); return null(); } TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::Operand)) return null(); if (tt == TOK_RB) break; if (tt == TOK_COMMA) { tokenStream.consumeKnownToken(TOK_COMMA, TokenStream::Operand); if (!handler.addElision(literal, pos())) return null(); } else if (tt == TOK_TRIPLEDOT) { tokenStream.consumeKnownToken(TOK_TRIPLEDOT, TokenStream::Operand); uint32_t begin = pos().begin; Node inner = assignExpr(InAllowed, yieldHandling, TripledotProhibited, possibleError); if (!inner) return null(); if (!handler.addSpreadElement(literal, begin, inner)) return null(); } else { Node element = assignExpr(InAllowed, yieldHandling, TripledotProhibited, possibleError); if (!element) return null(); if (foldConstants && !FoldConstants(context, &element, this)) return null(); handler.addArrayElement(literal, element); } if (tt != TOK_COMMA) { /* If we didn't already match TOK_COMMA in above case. */ bool matched; if (!tokenStream.matchToken(&matched, TOK_COMMA)) return null(); if (!matched) { modifier = TokenStream::None; break; } if (tt == TOK_TRIPLEDOT && possibleError) possibleError->setPendingDestructuringErrorAt(pos(), JSMSG_REST_WITH_COMMA); } } MUST_MATCH_TOKEN_MOD(TOK_RB, modifier, JSMSG_BRACKET_AFTER_LIST); } handler.setEndPosition(literal, pos().end); return literal; } static JSAtom* DoubleToAtom(ExclusiveContext* cx, double value) { // This is safe because doubles can not be moved. Value tmp = DoubleValue(value); return ToAtom(cx, HandleValue::fromMarkedLocation(&tmp)); } template typename ParseHandler::Node Parser::propertyName(YieldHandling yieldHandling, Node propList, PropertyType* propType, MutableHandleAtom propAtom) { TokenKind ltok; if (!tokenStream.getToken(<ok, TokenStream::KeywordIsName)) return null(); MOZ_ASSERT(ltok != TOK_RC, "caller should have handled TOK_RC"); bool isGenerator = false; bool isAsync = false; if (ltok == TOK_MUL) { isGenerator = true; if (!tokenStream.getToken(<ok, TokenStream::KeywordIsName)) return null(); } if (ltok == TOK_NAME && tokenStream.currentName() == context->names().async) { // AsyncMethod[Yield, Await]: // async [no LineTerminator here] PropertyName[?Yield, ?Await] ... // // PropertyName: // LiteralPropertyName // ComputedPropertyName[?Yield, ?Await] // // LiteralPropertyName: // IdentifierName // StringLiteral // NumericLiteral // // ComputedPropertyName[Yield, Await]: // [ ... TokenKind tt = TOK_EOF; if (!tokenStream.peekTokenSameLine(&tt, TokenStream::KeywordIsName)) return null(); if (tt == TOK_STRING || tt == TOK_NUMBER || tt == TOK_LB || tt == TOK_NAME || tt == TOK_YIELD) { isAsync = true; tokenStream.consumeKnownToken(tt, TokenStream::KeywordIsName); ltok = tt; } else { tokenStream.addModifierException(TokenStream::NoneIsKeywordIsName); } } if (isAsync && isGenerator) { error(JSMSG_ASYNC_GENERATOR); return null(); } propAtom.set(nullptr); Node propName; switch (ltok) { case TOK_NUMBER: propAtom.set(DoubleToAtom(context, tokenStream.currentToken().number())); if (!propAtom.get()) return null(); propName = newNumber(tokenStream.currentToken()); if (!propName) return null(); break; case TOK_LB: propName = computedPropertyName(yieldHandling, propList); if (!propName) return null(); break; case TOK_NAME: { propAtom.set(tokenStream.currentName()); // Do not look for accessor syntax on generators if (isGenerator || isAsync || !(propAtom.get() == context->names().get || propAtom.get() == context->names().set)) { propName = handler.newObjectLiteralPropertyName(propAtom, pos()); if (!propName) return null(); break; } *propType = propAtom.get() == context->names().get ? PropertyType::Getter : PropertyType::Setter; // We have parsed |get| or |set|. Look for an accessor property // name next. TokenKind tt; if (!tokenStream.peekToken(&tt, TokenStream::KeywordIsName)) return null(); if (tt == TOK_NAME) { if (!checkUnescapedName()) return null(); tokenStream.consumeKnownToken(TOK_NAME, TokenStream::KeywordIsName); propAtom.set(tokenStream.currentName()); return handler.newObjectLiteralPropertyName(propAtom, pos()); } if (tt == TOK_STRING) { if (!checkUnescapedName()) return null(); tokenStream.consumeKnownToken(TOK_STRING, TokenStream::KeywordIsName); propAtom.set(tokenStream.currentToken().atom()); uint32_t index; if (propAtom->isIndex(&index)) { propAtom.set(DoubleToAtom(context, index)); if (!propAtom.get()) return null(); return handler.newNumber(index, NoDecimal, pos()); } return stringLiteral(); } if (tt == TOK_NUMBER) { if (!checkUnescapedName()) return null(); tokenStream.consumeKnownToken(TOK_NUMBER, TokenStream::KeywordIsName); propAtom.set(DoubleToAtom(context, tokenStream.currentToken().number())); if (!propAtom.get()) return null(); return newNumber(tokenStream.currentToken()); } if (tt == TOK_LB) { if (!checkUnescapedName()) return null(); tokenStream.consumeKnownToken(TOK_LB, TokenStream::KeywordIsName); return computedPropertyName(yieldHandling, propList); } // Not an accessor property after all. propName = handler.newObjectLiteralPropertyName(propAtom.get(), pos()); if (!propName) return null(); tokenStream.addModifierException(TokenStream::NoneIsKeywordIsName); break; } case TOK_STRING: { propAtom.set(tokenStream.currentToken().atom()); uint32_t index; if (propAtom->isIndex(&index)) { propName = handler.newNumber(index, NoDecimal, pos()); if (!propName) return null(); break; } propName = stringLiteral(); if (!propName) return null(); break; } default: error(JSMSG_BAD_PROP_ID); return null(); } TokenKind tt; if (!tokenStream.getToken(&tt)) return null(); if (tt == TOK_COLON) { if (isGenerator) { error(JSMSG_BAD_PROP_ID); return null(); } *propType = PropertyType::Normal; return propName; } if (ltok == TOK_NAME && (tt == TOK_COMMA || tt == TOK_RC || tt == TOK_ASSIGN)) { if (isGenerator) { error(JSMSG_BAD_PROP_ID); return null(); } tokenStream.ungetToken(); *propType = tt == TOK_ASSIGN ? PropertyType::CoverInitializedName : PropertyType::Shorthand; return propName; } if (tt == TOK_LP) { tokenStream.ungetToken(); if (isGenerator) *propType = PropertyType::GeneratorMethod; else if (isAsync) *propType = PropertyType::AsyncMethod; else *propType = PropertyType::Method; return propName; } error(JSMSG_COLON_AFTER_ID); return null(); } template typename ParseHandler::Node Parser::computedPropertyName(YieldHandling yieldHandling, Node literal) { uint32_t begin = pos().begin; Node assignNode; { // Turn off the inDestructuringDecl flag when parsing computed property // names. In short, when parsing 'let {[x + y]: z} = obj;', noteUsedName() // should be called on x and y, but not on z. See the comment on // Parser<>::checkDestructuringPattern() for details. AutoClearInDestructuringDecl autoClear(pc); assignNode = assignExpr(InAllowed, yieldHandling, TripledotProhibited); if (!assignNode) return null(); } MUST_MATCH_TOKEN(TOK_RB, JSMSG_COMP_PROP_UNTERM_EXPR); Node propname = handler.newComputedName(assignNode, begin, pos().end); if (!propname) return null(); handler.setListFlag(literal, PNX_NONCONST); return propname; } template typename ParseHandler::Node Parser::objectLiteral(YieldHandling yieldHandling, PossibleError* possibleError) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LC)); Node literal = handler.newObjectLiteral(pos().begin); if (!literal) return null(); bool seenPrototypeMutation = false; bool seenCoverInitializedName = false; RootedAtom propAtom(context); for (;;) { TokenKind tt; if (!tokenStream.getToken(&tt, TokenStream::KeywordIsName)) return null(); if (tt == TOK_RC) break; TokenPos namePos = pos(); tokenStream.ungetToken(); PropertyType propType; Node propName = propertyName(yieldHandling, literal, &propType, &propAtom); if (!propName) return null(); if (propType == PropertyType::Normal) { Node propExpr = assignExpr(InAllowed, yieldHandling, TripledotProhibited, possibleError); if (!propExpr) return null(); handler.checkAndSetIsDirectRHSAnonFunction(propExpr); if (foldConstants && !FoldConstants(context, &propExpr, this)) return null(); if (propAtom == context->names().proto) { if (seenPrototypeMutation) { // Directly report the error when we're not in a // destructuring context. if (!possibleError) { errorAt(namePos.begin, JSMSG_DUPLICATE_PROTO_PROPERTY); return null(); } // Otherwise delay error reporting until we've determined // whether or not we're destructuring. possibleError->setPendingExpressionErrorAt(namePos, JSMSG_DUPLICATE_PROTO_PROPERTY); } seenPrototypeMutation = true; // Note: this occurs *only* if we observe TOK_COLON! Only // __proto__: v mutates [[Prototype]]. Getters, setters, // method/generator definitions, computed property name // versions of all of these, and shorthands do not. if (!handler.addPrototypeMutation(literal, namePos.begin, propExpr)) return null(); } else { if (!handler.isConstant(propExpr)) handler.setListFlag(literal, PNX_NONCONST); if (!handler.addPropertyDefinition(literal, propName, propExpr)) return null(); } } else if (propType == PropertyType::Shorthand) { /* * Support, e.g., |var {x, y} = o| as destructuring shorthand * for |var {x: x, y: y} = o|, and |var o = {x, y}| as initializer * shorthand for |var o = {x: x, y: y}|. */ TokenKind propToken = TOK_NAME; if (!tokenStream.checkForKeyword(propAtom, &propToken)) return null(); if (propToken != TOK_NAME && propToken != TOK_YIELD) { error(JSMSG_RESERVED_ID, TokenKindToDesc(propToken)); return null(); } Rooted name(context, identifierReference(yieldHandling, propToken == TOK_YIELD)); if (!name) return null(); Node nameExpr = identifierReference(name); if (!nameExpr) return null(); if (!handler.addShorthand(literal, propName, nameExpr)) return null(); } else if (propType == PropertyType::CoverInitializedName) { /* * Support, e.g., |var {x=1, y=2} = o| as destructuring shorthand * with default values, as per ES6 12.14.5 */ TokenKind propToken = TOK_NAME; if (!tokenStream.checkForKeyword(propAtom, &propToken)) return null(); if (propToken != TOK_NAME && propToken != TOK_YIELD) { error(JSMSG_RESERVED_ID, TokenKindToDesc(propToken)); return null(); } Rooted name(context, identifierReference(yieldHandling, propToken == TOK_YIELD)); if (!name) return null(); Node lhs = identifierReference(name); if (!lhs) return null(); tokenStream.consumeKnownToken(TOK_ASSIGN); if (!seenCoverInitializedName) { // "shorthand default" or "CoverInitializedName" syntax is only // valid in the case of destructuring. seenCoverInitializedName = true; if (!possibleError) { // Destructuring defaults are definitely not allowed in this object literal, // because of something the caller knows about the preceding code. // For example, maybe the preceding token is an operator: `x + {y=z}`. error(JSMSG_COLON_AFTER_ID); return null(); } // Here we set a pending error so that later in the parse, once we've // determined whether or not we're destructuring, the error can be // reported or ignored appropriately. possibleError->setPendingExpressionErrorAt(pos(), JSMSG_COLON_AFTER_ID); } Node rhs; { // Clearing `inDestructuringDecl` allows name use to be noted // in Parser::identifierReference. See bug 1255167. AutoClearInDestructuringDecl autoClear(pc); rhs = assignExpr(InAllowed, yieldHandling, TripledotProhibited); if (!rhs) return null(); } handler.checkAndSetIsDirectRHSAnonFunction(rhs); Node propExpr = handler.newAssignment(PNK_ASSIGN, lhs, rhs, JSOP_NOP); if (!propExpr) return null(); if (!handler.addPropertyDefinition(literal, propName, propExpr)) return null(); if (!abortIfSyntaxParser()) return null(); } else { RootedAtom funName(context); if (!tokenStream.isCurrentTokenType(TOK_RB)) { funName = propAtom; if (propType == PropertyType::Getter || propType == PropertyType::Setter) { funName = prefixAccessorName(propType, propAtom); if (!funName) return null(); } } Node fn = methodDefinition(namePos.begin, propType, funName); if (!fn) return null(); handler.checkAndSetIsDirectRHSAnonFunction(fn); JSOp op = JSOpFromPropertyType(propType); if (!handler.addObjectMethodDefinition(literal, propName, fn, op)) return null(); } if (!tokenStream.getToken(&tt)) return null(); if (tt == TOK_RC) break; if (tt != TOK_COMMA) { error(JSMSG_CURLY_AFTER_LIST); return null(); } } handler.setEndPosition(literal, pos().end); return literal; } template typename ParseHandler::Node Parser::methodDefinition(uint32_t preludeStart, PropertyType propType, HandleAtom funName) { FunctionSyntaxKind kind; switch (propType) { case PropertyType::Getter: kind = Getter; break; case PropertyType::GetterNoExpressionClosure: kind = GetterNoExpressionClosure; break; case PropertyType::Setter: kind = Setter; break; case PropertyType::SetterNoExpressionClosure: kind = SetterNoExpressionClosure; break; case PropertyType::Method: case PropertyType::GeneratorMethod: case PropertyType::AsyncMethod: kind = Method; break; case PropertyType::Constructor: kind = ClassConstructor; break; case PropertyType::DerivedConstructor: kind = DerivedClassConstructor; break; default: MOZ_CRASH("Parser: methodDefinition: unexpected property type"); } GeneratorKind generatorKind = (propType == PropertyType::GeneratorMethod || propType == PropertyType::AsyncMethod) ? StarGenerator : NotGenerator; FunctionAsyncKind asyncKind = (propType == PropertyType::AsyncMethod) ? AsyncFunction : SyncFunction; YieldHandling yieldHandling = GetYieldHandling(generatorKind, asyncKind); Node pn = handler.newFunctionExpression(); if (!pn) return null(); return functionDefinition(preludeStart, pn, InAllowed, yieldHandling, funName, kind, generatorKind, asyncKind); } template bool Parser::tryNewTarget(Node &newTarget) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_NEW)); newTarget = null(); Node newHolder = handler.newPosHolder(pos()); if (!newHolder) return false; uint32_t begin = pos().begin; // |new| expects to look for an operand, so we will honor that. TokenKind next; if (!tokenStream.getToken(&next, TokenStream::Operand)) return false; // Don't unget the token, since lookahead cannot handle someone calling // getToken() with a different modifier. Callers should inspect currentToken(). if (next != TOK_DOT) return true; if (!tokenStream.getToken(&next)) return false; if (next != TOK_NAME || tokenStream.currentName() != context->names().target) { error(JSMSG_UNEXPECTED_TOKEN, "target", TokenKindToDesc(next)); return false; } if (!checkUnescapedName()) return false; if (!pc->sc()->allowNewTarget()) { errorAt(begin, JSMSG_BAD_NEWTARGET); return false; } Node targetHolder = handler.newPosHolder(pos()); if (!targetHolder) return false; newTarget = handler.newNewTarget(newHolder, targetHolder); return !!newTarget; } template typename ParseHandler::Node Parser::primaryExpr(YieldHandling yieldHandling, TripledotHandling tripledotHandling, TokenKind tt, PossibleError* possibleError, InvokedPrediction invoked /* = PredictUninvoked */) { MOZ_ASSERT(tokenStream.isCurrentTokenType(tt)); JS_CHECK_RECURSION(context, return null()); switch (tt) { case TOK_FUNCTION: return functionExpr(pos().begin, invoked); case TOK_CLASS: return classDefinition(yieldHandling, ClassExpression, NameRequired); case TOK_LB: return arrayInitializer(yieldHandling, possibleError); case TOK_LC: return objectLiteral(yieldHandling, possibleError); case TOK_LP: { TokenKind next; if (!tokenStream.peekToken(&next, TokenStream::Operand)) return null(); if (next == TOK_RP) { // Not valid expression syntax, but this is valid in an arrow function // with no params: `() => body`. tokenStream.consumeKnownToken(next, TokenStream::Operand); if (!tokenStream.peekToken(&next)) return null(); if (next != TOK_ARROW) { error(JSMSG_UNEXPECTED_TOKEN, "expression", TokenKindToDesc(TOK_RP)); return null(); } // Now just return something that will allow parsing to continue. // It doesn't matter what; when we reach the =>, we will rewind and // reparse the whole arrow function. See Parser::assignExpr. return handler.newNullLiteral(pos()); } if (next == TOK_FOR) { uint32_t begin = pos().begin; tokenStream.consumeKnownToken(next, TokenStream::Operand); return generatorComprehension(begin); } // Pass |possibleError| to support destructuring in arrow parameters. Node expr = exprInParens(InAllowed, yieldHandling, TripledotAllowed, possibleError); if (!expr) return null(); MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_IN_PAREN); handler.setEndPosition(expr, pos().end); return handler.parenthesize(expr); } case TOK_TEMPLATE_HEAD: return templateLiteral(yieldHandling); case TOK_NO_SUBS_TEMPLATE: return noSubstitutionTemplate(); case TOK_STRING: return stringLiteral(); case TOK_YIELD: case TOK_NAME: { if (tokenStream.currentName() == context->names().async) { TokenKind nextSameLine = TOK_EOF; if (!tokenStream.peekTokenSameLine(&nextSameLine)) return null(); if (nextSameLine == TOK_FUNCTION) { uint32_t preludeStart = pos().begin; tokenStream.consumeKnownToken(TOK_FUNCTION); return functionExpr(preludeStart, PredictUninvoked, AsyncFunction); } } Rooted name(context, identifierReference(yieldHandling)); if (!name) return null(); return identifierReference(name); } case TOK_REGEXP: return newRegExp(); case TOK_NUMBER: return newNumber(tokenStream.currentToken()); case TOK_TRUE: return handler.newBooleanLiteral(true, pos()); case TOK_FALSE: return handler.newBooleanLiteral(false, pos()); case TOK_THIS: { if (pc->isFunctionBox()) pc->functionBox()->usesThis = true; Node thisName = null(); if (pc->sc()->thisBinding() == ThisBinding::Function) { thisName = newThisName(); if (!thisName) return null(); } return handler.newThisLiteral(pos(), thisName); } case TOK_NULL: return handler.newNullLiteral(pos()); case TOK_TRIPLEDOT: { // This isn't valid expression syntax, but it's valid in an arrow // function as a trailing rest param: `(a, b, ...rest) => body`. Check // if it's directly under // CoverParenthesizedExpressionAndArrowParameterList, and check for a // name, closing parenthesis, and arrow, and allow it only if all are // present. if (tripledotHandling != TripledotAllowed) { error(JSMSG_UNEXPECTED_TOKEN, "expression", TokenKindToDesc(tt)); return null(); } TokenKind next; if (!tokenStream.getToken(&next)) return null(); if (next == TOK_LB || next == TOK_LC) { // Validate, but don't store the pattern right now. The whole arrow // function is reparsed in functionFormalParametersAndBody(). if (!destructuringDeclaration(DeclarationKind::CoverArrowParameter, yieldHandling, next)) { return null(); } } else { // This doesn't check that the provided name is allowed, e.g. if // the enclosing code is strict mode code, any of "let", "yield", // or "arguments" should be prohibited. Argument-parsing code // handles that. if (next != TOK_NAME && next != TOK_YIELD) { error(JSMSG_UNEXPECTED_TOKEN, "rest argument name", TokenKindToDesc(next)); return null(); } } if (!tokenStream.getToken(&next)) return null(); if (next != TOK_RP) { error(JSMSG_UNEXPECTED_TOKEN, "closing parenthesis", TokenKindToDesc(next)); return null(); } if (!tokenStream.peekToken(&next)) return null(); if (next != TOK_ARROW) { // Advance the scanner for proper error location reporting. tokenStream.consumeKnownToken(next); error(JSMSG_UNEXPECTED_TOKEN, "'=>' after argument list", TokenKindToDesc(next)); return null(); } tokenStream.ungetToken(); // put back right paren // Return an arbitrary expression node. See case TOK_RP above. return handler.newNullLiteral(pos()); } default: error(JSMSG_UNEXPECTED_TOKEN, "expression", TokenKindToDesc(tt)); return null(); } } template typename ParseHandler::Node Parser::exprInParens(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError /* = nullptr */) { MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LP)); return expr(inHandling, yieldHandling, tripledotHandling, possibleError, PredictInvoked); } template bool Parser::warnOnceAboutExprClosure() { #ifndef RELEASE_OR_BETA JSContext* cx = context->maybeJSContext(); if (!cx) return true; if (!cx->compartment()->warnedAboutExprClosure) { if (!warning(JSMSG_DEPRECATED_EXPR_CLOSURE)) return false; cx->compartment()->warnedAboutExprClosure = true; } #endif return true; } template bool Parser::warnOnceAboutForEach() { JSContext* cx = context->maybeJSContext(); if (!cx) return true; if (!cx->compartment()->warnedAboutForEach) { // Disabled warning spew. // if (!warning(JSMSG_DEPRECATED_FOR_EACH)) // return false; cx->compartment()->warnedAboutForEach = true; } return true; } template class Parser; template class Parser; } /* namespace frontend */ } /* namespace js */