/* -*- 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. */ #ifndef frontend_Parser_h #define frontend_Parser_h #include "mozilla/Array.h" #include "mozilla/Maybe.h" #include "jspubtd.h" #include "frontend/BytecodeCompiler.h" #include "frontend/FullParseHandler.h" #include "frontend/NameAnalysisTypes.h" #include "frontend/NameCollections.h" #include "frontend/SharedContext.h" #include "frontend/SyntaxParseHandler.h" namespace js { class ModuleObject; namespace frontend { /* * The struct ParseContext stores information about the current parsing context, * which is part of the parser state (see the field Parser::pc). The current * parsing context is either the global context, or the function currently being * parsed. When the parser encounters a function definition, it creates a new * ParseContext, makes it the new current context. */ class ParseContext : public Nestable { public: // The intra-function statement stack. // // Used for early error checking that depend on the nesting structure of // statements, such as continue/break targets, labels, and unbraced // lexical declarations. class Statement : public Nestable { StatementKind kind_; public: using Nestable::enclosing; using Nestable::findNearest; Statement(ParseContext* pc, StatementKind kind) : Nestable(&pc->innermostStatement_), kind_(kind) { } template inline bool is() const; template inline T& as(); StatementKind kind() const { return kind_; } void refineForKind(StatementKind newForKind) { MOZ_ASSERT(kind_ == StatementKind::ForLoop); MOZ_ASSERT(newForKind == StatementKind::ForInLoop || newForKind == StatementKind::ForOfLoop); kind_ = newForKind; } }; class LabelStatement : public Statement { RootedAtom label_; public: LabelStatement(ParseContext* pc, JSAtom* label) : Statement(pc, StatementKind::Label), label_(pc->sc_->context, label) { } HandleAtom label() const { return label_; } }; class ClassStatement : public Statement { FunctionBox* constructorBox_; public: explicit ClassStatement(ParseContext* pc) : Statement(pc, StatementKind::Class), constructorBox_(nullptr) { } void clearConstructorBoxForAbortedSyntaxParse(FunctionBox* funbox) { MOZ_ASSERT(constructorBox_ == funbox); constructorBox_ = nullptr; } void setConstructorBox(FunctionBox* funbox) { MOZ_ASSERT(!constructorBox_); constructorBox_ = funbox; } FunctionBox* constructorBox() const { return constructorBox_; } }; // The intra-function scope stack. // // Tracks declared and used names within a scope. class Scope : public Nestable { // Names declared in this scope. Corresponds to the union of // VarDeclaredNames and LexicallyDeclaredNames in the ES spec. // // A 'var' declared name is a member of the declared name set of every // scope in its scope contour. // // A lexically declared name is a member only of the declared name set of // the scope in which it is declared. PooledMapPtr declared_; // Monotonically increasing id. uint32_t id_; bool maybeReportOOM(ParseContext* pc, bool result) { if (!result) ReportOutOfMemory(pc->sc()->context); return result; } public: using DeclaredNamePtr = DeclaredNameMap::Ptr; using AddDeclaredNamePtr = DeclaredNameMap::AddPtr; using Nestable::enclosing; template explicit Scope(Parser* parser) : Nestable(&parser->pc->innermostScope_), declared_(parser->context->frontendCollectionPool()), id_(parser->usedNames.nextScopeId()) { } void dump(ParseContext* pc); uint32_t id() const { return id_; } MOZ_MUST_USE bool init(ParseContext* pc) { if (id_ == UINT32_MAX) { pc->tokenStream_.reportError(JSMSG_NEED_DIET, js_script_str); return false; } return declared_.acquire(pc->sc()->context); } DeclaredNamePtr lookupDeclaredName(JSAtom* name) { return declared_->lookup(name); } AddDeclaredNamePtr lookupDeclaredNameForAdd(JSAtom* name) { return declared_->lookupForAdd(name); } MOZ_MUST_USE bool addDeclaredName(ParseContext* pc, AddDeclaredNamePtr& p, JSAtom* name, DeclarationKind kind, uint32_t pos) { return maybeReportOOM(pc, declared_->add(p, name, DeclaredNameInfo(kind, pos))); } // Remove all VarForAnnexBLexicalFunction declarations of a certain // name from all scopes in pc's scope stack. static void removeVarForAnnexBLexicalFunction(ParseContext* pc, JSAtom* name); // Add and remove catch parameter names. Used to implement the odd // semantics of catch bodies. bool addCatchParameters(ParseContext* pc, Scope& catchParamScope); void removeCatchParameters(ParseContext* pc, Scope& catchParamScope); void useAsVarScope(ParseContext* pc) { MOZ_ASSERT(!pc->varScope_); pc->varScope_ = this; } // An iterator for the set of names a scope binds: the set of all // declared names for 'var' scopes, and the set of lexically declared // names for non-'var' scopes. class BindingIter { friend class Scope; DeclaredNameMap::Range declaredRange_; mozilla::DebugOnly count_; bool isVarScope_; BindingIter(Scope& scope, bool isVarScope) : declaredRange_(scope.declared_->all()), count_(0), isVarScope_(isVarScope) { settle(); } void settle() { // Both var and lexically declared names are binding in a var // scope. if (isVarScope_) return; // Otherwise, pop only lexically declared names are // binding. Pop the range until we find such a name. while (!declaredRange_.empty()) { if (BindingKindIsLexical(kind())) break; declaredRange_.popFront(); } } public: bool done() const { return declaredRange_.empty(); } explicit operator bool() const { return !done(); } JSAtom* name() { MOZ_ASSERT(!done()); return declaredRange_.front().key(); } DeclarationKind declarationKind() { MOZ_ASSERT(!done()); return declaredRange_.front().value()->kind(); } BindingKind kind() { return DeclarationKindToBindingKind(declarationKind()); } bool closedOver() { MOZ_ASSERT(!done()); return declaredRange_.front().value()->closedOver(); } void setClosedOver() { MOZ_ASSERT(!done()); return declaredRange_.front().value()->setClosedOver(); } void operator++(int) { MOZ_ASSERT(!done()); MOZ_ASSERT(count_ != UINT32_MAX); declaredRange_.popFront(); settle(); } }; inline BindingIter bindings(ParseContext* pc); }; class VarScope : public Scope { public: template explicit VarScope(Parser* parser) : Scope(parser) { useAsVarScope(parser->pc); } }; private: // Context shared between parsing and bytecode generation. SharedContext* sc_; // TokenStream used for error reporting. TokenStream& tokenStream_; // The innermost statement, i.e., top of the statement stack. Statement* innermostStatement_; // The innermost scope, i.e., top of the scope stack. // // The outermost scope in the stack is usually varScope_. In the case of // functions, the outermost scope is functionScope_, which may be // varScope_. See comment above functionScope_. Scope* innermostScope_; // If isFunctionBox() and the function is a named lambda, the DeclEnv // scope for named lambdas. mozilla::Maybe namedLambdaScope_; // If isFunctionBox(), the scope for the function. If there are no // parameter expressions, this is scope for the entire function. If there // are parameter expressions, this holds the special function names // ('.this', 'arguments') and the formal parameers. mozilla::Maybe functionScope_; // The body-level scope. This always exists, but not necessarily at the // beginning of parsing the script in the case of functions with parameter // expressions. Scope* varScope_; // Inner function boxes in this context to try Annex B.3.3 semantics // on. Only used when full parsing. PooledVectorPtr innerFunctionBoxesForAnnexB_; // Simple formal parameter names, in order of appearance. Only used when // isFunctionBox(). PooledVectorPtr positionalFormalParameterNames_; // Closed over binding names, in order of appearance. Null-delimited // between scopes. Only used when syntax parsing. PooledVectorPtr closedOverBindingsForLazy_; // Monotonically increasing id. uint32_t scriptId_; // Set when compiling a function using Parser::standaloneFunctionBody via // the Function or Generator constructor. bool isStandaloneFunctionBody_; // Set when encountering a super.property inside a method. We need to mark // the nearest super scope as needing a home object. bool superScopeNeedsHomeObject_; public: // lastYieldOffset stores the offset of the last yield that was parsed. // NoYieldOffset is its initial value. static const uint32_t NoYieldOffset = UINT32_MAX; uint32_t lastYieldOffset; // lastAwaitOffset stores the offset of the last await that was parsed. // NoAwaitOffset is its initial value. static const uint32_t NoAwaitOffset = UINT32_MAX; uint32_t lastAwaitOffset; // All inner functions in this context. Only used when syntax parsing. Rooted> innerFunctionsForLazy; // In a function context, points to a Directive struct that can be updated // to reflect new directives encountered in the Directive Prologue that // require reparsing the function. In global/module/generator-tail contexts, // we don't need to reparse when encountering a DirectivePrologue so this // pointer may be nullptr. Directives* newDirectives; // Set when parsing a declaration-like destructuring pattern. This flag // causes PrimaryExpr to create PN_NAME parse nodes for variable references // which are not hooked into any definition's use chain, added to any tree // context's AtomList, etc. etc. checkDestructuring will do that work // later. // // The comments atop checkDestructuring explain the distinction between // assignment-like and declaration-like destructuring patterns, and why // they need to be treated differently. mozilla::Maybe inDestructuringDecl; // Set when parsing a function and it has 'return ;' bool funHasReturnExpr; // Set when parsing a function and it has 'return;' bool funHasReturnVoid; public: template ParseContext(Parser* prs, SharedContext* sc, Directives* newDirectives) : Nestable(&prs->pc), sc_(sc), tokenStream_(prs->tokenStream), innermostStatement_(nullptr), innermostScope_(nullptr), varScope_(nullptr), innerFunctionBoxesForAnnexB_(prs->context->frontendCollectionPool()), positionalFormalParameterNames_(prs->context->frontendCollectionPool()), closedOverBindingsForLazy_(prs->context->frontendCollectionPool()), scriptId_(prs->usedNames.nextScriptId()), isStandaloneFunctionBody_(false), superScopeNeedsHomeObject_(false), lastYieldOffset(NoYieldOffset), lastAwaitOffset(NoAwaitOffset), innerFunctionsForLazy(prs->context, GCVector(prs->context)), newDirectives(newDirectives), funHasReturnExpr(false), funHasReturnVoid(false) { if (isFunctionBox()) { if (functionBox()->function()->isNamedLambda()) namedLambdaScope_.emplace(prs); functionScope_.emplace(prs); } } ~ParseContext(); MOZ_MUST_USE bool init(); SharedContext* sc() { return sc_; } bool isFunctionBox() const { return sc_->isFunctionBox(); } FunctionBox* functionBox() { return sc_->asFunctionBox(); } Statement* innermostStatement() { return innermostStatement_; } Scope* innermostScope() { // There is always at least one scope: the 'var' scope. MOZ_ASSERT(innermostScope_); return innermostScope_; } Scope& namedLambdaScope() { MOZ_ASSERT(functionBox()->function()->isNamedLambda()); return *namedLambdaScope_; } Scope& functionScope() { MOZ_ASSERT(isFunctionBox()); return *functionScope_; } Scope& varScope() { MOZ_ASSERT(varScope_); return *varScope_; } bool isFunctionExtraBodyVarScopeInnermost() { return isFunctionBox() && functionBox()->hasParameterExprs && innermostScope() == varScope_; } template bool */> Statement* findInnermostStatement(Predicate predicate) { return Statement::findNearest(innermostStatement_, predicate); } template bool */> T* findInnermostStatement(Predicate predicate) { return Statement::findNearest(innermostStatement_, predicate); } template T* findInnermostStatement() { return Statement::findNearest(innermostStatement_); } AtomVector& positionalFormalParameterNames() { return *positionalFormalParameterNames_; } AtomVector& closedOverBindingsForLazy() { return *closedOverBindingsForLazy_; } MOZ_MUST_USE bool addInnerFunctionBoxForAnnexB(FunctionBox* funbox); void removeInnerFunctionBoxesForAnnexB(JSAtom* name); void finishInnerFunctionBoxesForAnnexB(); // True if we are at the topmost level of a entire script or function body. // For example, while parsing this code we would encounter f1 and f2 at // body level, but we would not encounter f3 or f4 at body level: // // function f1() { function f2() { } } // if (cond) { function f3() { if (cond) { function f4() { } } } } // bool atBodyLevel() { return !innermostStatement_; } bool atGlobalLevel() { return atBodyLevel() && sc_->isGlobalContext(); } // True if we are at the topmost level of a module only. bool atModuleLevel() { return atBodyLevel() && sc_->isModuleContext(); } void setIsStandaloneFunctionBody() { isStandaloneFunctionBody_ = true; } bool isStandaloneFunctionBody() const { return isStandaloneFunctionBody_; } void setSuperScopeNeedsHomeObject() { MOZ_ASSERT(sc_->allowSuperProperty()); superScopeNeedsHomeObject_ = true; } bool superScopeNeedsHomeObject() const { return superScopeNeedsHomeObject_; } bool useAsmOrInsideUseAsm() const { return sc_->isFunctionBox() && sc_->asFunctionBox()->useAsmOrInsideUseAsm(); } // Most functions start off being parsed as non-generators. // Non-generators transition to LegacyGenerator on parsing "yield" in JS 1.7. // An ES6 generator is marked as a "star generator" before its body is parsed. GeneratorKind generatorKind() const { return sc_->isFunctionBox() ? sc_->asFunctionBox()->generatorKind() : NotGenerator; } bool isGenerator() const { return generatorKind() != NotGenerator; } bool isLegacyGenerator() const { return generatorKind() == LegacyGenerator; } bool isStarGenerator() const { return generatorKind() == StarGenerator; } bool isAsync() const { return sc_->isFunctionBox() && sc_->asFunctionBox()->isAsync(); } FunctionAsyncKind asyncKind() const { return isAsync() ? AsyncFunction : SyncFunction; } bool isArrowFunction() const { return sc_->isFunctionBox() && sc_->asFunctionBox()->function()->isArrow(); } bool isMethod() const { return sc_->isFunctionBox() && sc_->asFunctionBox()->function()->isMethod(); } uint32_t scriptId() const { return scriptId_; } }; template <> inline bool ParseContext::Statement::is() const { return kind_ == StatementKind::Label; } template <> inline bool ParseContext::Statement::is() const { return kind_ == StatementKind::Class; } template inline T& ParseContext::Statement::as() { MOZ_ASSERT(is()); return static_cast(*this); } inline ParseContext::Scope::BindingIter ParseContext::Scope::bindings(ParseContext* pc) { // In function scopes with parameter expressions, function special names // (like '.this') are declared as vars in the function scope, despite its // not being the var scope. return BindingIter(*this, pc->varScope_ == this || pc->functionScope_.ptrOr(nullptr) == this); } inline Directives::Directives(ParseContext* parent) : strict_(parent->sc()->strict()), asmJS_(parent->useAsmOrInsideUseAsm()) {} enum VarContext { HoistVars, DontHoistVars }; enum PropListType { ObjectLiteral, ClassBody, DerivedClassBody }; enum class PropertyType { Normal, Shorthand, CoverInitializedName, Getter, GetterNoExpressionClosure, Setter, SetterNoExpressionClosure, Method, GeneratorMethod, AsyncMethod, Constructor, DerivedConstructor }; // Specify a value for an ES6 grammar parametrization. We have no enum for // [Return] because its behavior is exactly equivalent to checking whether // we're in a function box -- easier and simpler than passing an extra // parameter everywhere. enum YieldHandling { YieldIsName, YieldIsKeyword }; enum InHandling { InAllowed, InProhibited }; enum DefaultHandling { NameRequired, AllowDefaultName }; enum TripledotHandling { TripledotAllowed, TripledotProhibited }; // A data structure for tracking used names per parsing session in order to // compute which bindings are closed over. Scripts and scopes are numbered // monotonically in textual order and name uses are tracked by lists of // (script id, scope id) pairs of their use sites. // // Intuitively, in a pair (P,S), P tracks the most nested function that has a // use of u, and S tracks the most nested scope that is still being parsed. // // P is used to answer the question "is u used by a nested function?" // S is used to answer the question "is u used in any scopes currently being // parsed?" // // The algorithm: // // Let Used by a map of names to lists. // // 1. Number all scopes in monotonic increasing order in textual order. // 2. Number all scripts in monotonic increasing order in textual order. // 3. When an identifier u is used in scope numbered S in script numbered P, // and u is found in Used, // a. Append (P,S) to Used[u]. // b. Otherwise, assign the the list [(P,S)] to Used[u]. // 4. When we finish parsing a scope S in script P, for each declared name d in // Declared(S): // a. If d is found in Used, mark d as closed over if there is a value // (P_d, S_d) in Used[d] such that P_d > P and S_d > S. // b. Remove all values (P_d, S_d) in Used[d] such that S_d are >= S. // // Steps 1 and 2 are implemented by UsedNameTracker::next{Script,Scope}Id. // Step 3 is implemented by UsedNameTracker::noteUsedInScope. // Step 4 is implemented by UsedNameTracker::noteBoundInScope and // Parser::propagateFreeNamesAndMarkClosedOverBindings. class UsedNameTracker { public: struct Use { uint32_t scriptId; uint32_t scopeId; }; class UsedNameInfo { friend class UsedNameTracker; Vector uses_; void resetToScope(uint32_t scriptId, uint32_t scopeId); public: explicit UsedNameInfo(ExclusiveContext* cx) : uses_(cx) { } UsedNameInfo(UsedNameInfo&& other) : uses_(mozilla::Move(other.uses_)) { } bool noteUsedInScope(uint32_t scriptId, uint32_t scopeId) { if (uses_.empty() || uses_.back().scopeId < scopeId) return uses_.append(Use { scriptId, scopeId }); return true; } void noteBoundInScope(uint32_t scriptId, uint32_t scopeId, bool* closedOver) { *closedOver = false; while (!uses_.empty()) { Use& innermost = uses_.back(); if (innermost.scopeId < scopeId) break; if (innermost.scriptId > scriptId) *closedOver = true; uses_.popBack(); } } bool isUsedInScript(uint32_t scriptId) const { return !uses_.empty() && uses_.back().scriptId >= scriptId; } }; using UsedNameMap = HashMap>; private: // The map of names to chains of uses. UsedNameMap map_; // Monotonically increasing id for all nested scripts. uint32_t scriptCounter_; // Monotonically increasing id for all nested scopes. uint32_t scopeCounter_; public: explicit UsedNameTracker(ExclusiveContext* cx) : map_(cx), scriptCounter_(0), scopeCounter_(0) { } MOZ_MUST_USE bool init() { return map_.init(); } uint32_t nextScriptId() { MOZ_ASSERT(scriptCounter_ != UINT32_MAX, "ParseContext::Scope::init should have prevented wraparound"); return scriptCounter_++; } uint32_t nextScopeId() { MOZ_ASSERT(scopeCounter_ != UINT32_MAX); return scopeCounter_++; } UsedNameMap::Ptr lookup(JSAtom* name) const { return map_.lookup(name); } MOZ_MUST_USE bool noteUse(ExclusiveContext* cx, JSAtom* name, uint32_t scriptId, uint32_t scopeId); struct RewindToken { private: friend class UsedNameTracker; uint32_t scriptId; uint32_t scopeId; }; RewindToken getRewindToken() const { RewindToken token; token.scriptId = scriptCounter_; token.scopeId = scopeCounter_; return token; } // Resets state so that scriptId and scopeId are the innermost script and // scope, respectively. Used for rewinding state on syntax parse failure. void rewind(RewindToken token); // Resets state to beginning of compilation. void reset() { map_.clear(); RewindToken token; token.scriptId = 0; token.scopeId = 0; rewind(token); } }; template class AutoAwaitIsKeyword; class ParserBase : public StrictModeGetter { private: ParserBase* thisForCtor() { return this; } public: ExclusiveContext* const context; LifoAlloc& alloc; TokenStream tokenStream; LifoAlloc::Mark tempPoolMark; /* list of parsed objects for GC tracing */ ObjectBox* traceListHead; /* innermost parse context (stack-allocated) */ ParseContext* pc; // For tracking used names in this parsing session. UsedNameTracker& usedNames; /* Compression token for aborting. */ SourceCompressionTask* sct; ScriptSource* ss; /* Root atoms and objects allocated for the parsed tree. */ AutoKeepAtoms keepAtoms; /* Perform constant-folding; must be true when interfacing with the emitter. */ const bool foldConstants:1; protected: #if DEBUG /* Our fallible 'checkOptions' member function has been called. */ bool checkOptionsCalled:1; #endif /* * Not all language constructs can be handled during syntax parsing. If it * is not known whether the parse succeeds or fails, this bit is set and * the parse will return false. */ bool abortedSyntaxParse:1; /* Unexpected end of input, i.e. TOK_EOF not at top-level. */ bool isUnexpectedEOF_:1; bool awaitIsKeyword_:1; public: bool awaitIsKeyword() const { return awaitIsKeyword_; } ParserBase(ExclusiveContext* cx, LifoAlloc& alloc, const ReadOnlyCompileOptions& options, const char16_t* chars, size_t length, bool foldConstants, UsedNameTracker& usedNames, Parser* syntaxParser, LazyScript* lazyOuterFunction); ~ParserBase(); const char* getFilename() const { return tokenStream.getFilename(); } JSVersion versionNumber() const { return tokenStream.versionNumber(); } TokenPos pos() const { return tokenStream.currentToken().pos; } // Determine whether |yield| is a valid name in the current context, or // whether it's prohibited due to strictness, JS version, or occurrence // inside a star generator. bool yieldExpressionsSupported() { return (versionNumber() >= JSVERSION_1_7 || pc->isGenerator()) && !pc->isAsync(); } virtual bool strictMode() { return pc->sc()->strict(); } bool setLocalStrictMode(bool strict) { MOZ_ASSERT(tokenStream.debugHasNoLookahead()); return pc->sc()->setLocalStrictMode(strict); } const ReadOnlyCompileOptions& options() const { return tokenStream.options(); } bool hadAbortedSyntaxParse() { return abortedSyntaxParse; } void clearAbortedSyntaxParse() { abortedSyntaxParse = false; } bool isUnexpectedEOF() const { return isUnexpectedEOF_; } bool reportNoOffset(ParseReportKind kind, bool strict, unsigned errorNumber, ...); /* Report the given error at the current offset. */ void error(unsigned errorNumber, ...); void errorWithNotes(UniquePtr notes, unsigned errorNumber, ...); /* Report the given error at the given offset. */ void errorAt(uint32_t offset, unsigned errorNumber, ...); void errorWithNotesAt(UniquePtr notes, uint32_t offset, unsigned errorNumber, ...); /* * Handle a strict mode error at the current offset. Report an error if in * strict mode code, or warn if not, using the given error number and * arguments. */ MOZ_MUST_USE bool strictModeError(unsigned errorNumber, ...); /* * Handle a strict mode error at the given offset. Report an error if in * strict mode code, or warn if not, using the given error number and * arguments. */ MOZ_MUST_USE bool strictModeErrorAt(uint32_t offset, unsigned errorNumber, ...); /* Report the given warning at the current offset. */ MOZ_MUST_USE bool warning(unsigned errorNumber, ...); /* Report the given warning at the given offset. */ MOZ_MUST_USE bool warningAt(uint32_t offset, unsigned errorNumber, ...); /* * If extra warnings are enabled, report the given warning at the current * offset. */ MOZ_MUST_USE bool extraWarning(unsigned errorNumber, ...); bool isValidStrictBinding(PropertyName* name); bool warnOnceAboutExprClosure(); bool warnOnceAboutForEach(); protected: enum InvokedPrediction { PredictUninvoked = false, PredictInvoked = true }; enum ForInitLocation { InForInit, NotInForInit }; }; template class Parser final : public ParserBase, private JS::AutoGCRooter { private: using Node = typename ParseHandler::Node; /* * A class for temporarily stashing errors while parsing continues. * * The ability to stash an error is useful for handling situations where we * aren't able to verify that an error has occurred until later in the parse. * For instance | ({x=1}) | is always parsed as an object literal with * a SyntaxError, however, in the case where it is followed by '=>' we rewind * and reparse it as a valid arrow function. Here a PossibleError would be * set to 'pending' when the initial SyntaxError was encountered then 'resolved' * just before rewinding the parser. * * There are currently two kinds of PossibleErrors: Expression and * Destructuring errors. Expression errors are used to mark a possible * syntax error when a grammar production is used in an expression context. * For example in |{x = 1}|, we mark the CoverInitializedName |x = 1| as a * possible expression error, because CoverInitializedName productions * are disallowed when an actual ObjectLiteral is expected. * Destructuring errors are used to record possible syntax errors in * destructuring contexts. For example in |[...rest, ] = []|, we initially * mark the trailing comma after the spread expression as a possible * destructuring error, because the ArrayAssignmentPattern grammar * production doesn't allow a trailing comma after the rest element. * * When using PossibleError one should set a pending error at the location * where an error occurs. From that point, the error may be resolved * (invalidated) or left until the PossibleError is checked. * * Ex: * PossibleError possibleError(*this); * possibleError.setPendingExpressionErrorAt(pos, JSMSG_BAD_PROP_ID); * // A JSMSG_BAD_PROP_ID ParseError is reported, returns false. * if (!possibleError.checkForExpressionError()) * return false; // we reach this point with a pending exception * * PossibleError possibleError(*this); * possibleError.setPendingExpressionErrorAt(pos, JSMSG_BAD_PROP_ID); * // Returns true, no error is reported. * if (!possibleError.checkForDestructuringError()) * return false; // not reached, no pending exception * * PossibleError possibleError(*this); * // Returns true, no error is reported. * if (!possibleError.checkForExpressionError()) * return false; // not reached, no pending exception */ class MOZ_STACK_CLASS PossibleError { private: enum class ErrorKind { Expression, Destructuring }; enum class ErrorState { None, Pending }; struct Error { ErrorState state_ = ErrorState::None; // Error reporting fields. uint32_t offset_; unsigned errorNumber_; }; Parser& parser_; Error exprError_; Error destructuringError_; // Returns the error report. Error& error(ErrorKind kind); // Return true if an error is pending without reporting bool hasError(ErrorKind kind); // Resolve any pending error. void setResolved(ErrorKind kind); // Set a pending error. Only a single error may be set per instance and // error kind. void setPending(ErrorKind kind, const TokenPos& pos, unsigned errorNumber); // If there is a pending error, report it and return false, otherwise // return true. bool checkForError(ErrorKind kind); // Transfer an existing error to another instance. void transferErrorTo(ErrorKind kind, PossibleError* other); public: explicit PossibleError(Parser& parser); // Set a pending destructuring error. Only a single error may be set // per instance, i.e. subsequent calls to this method are ignored and // won't overwrite the existing pending error. void setPendingDestructuringErrorAt(const TokenPos& pos, unsigned errorNumber); // Set a pending expression error. Only a single error may be set per // instance, i.e. subsequent calls to this method are ignored and won't // overwrite the existing pending error. void setPendingExpressionErrorAt(const TokenPos& pos, unsigned errorNumber); // If there is a pending destructuring error, report it and return // false, otherwise return true. Clears any pending expression error. bool checkForDestructuringError(); // If there is a pending expression error, report it and return false, // otherwise return true. Clears any pending destructuring error. bool checkForExpressionError(); // Pass pending errors between possible error instances. This is useful // for extending the lifetime of a pending error beyond the scope of // the PossibleError where it was initially set (keeping in mind that // PossibleError is a MOZ_STACK_CLASS). void transferErrorsTo(PossibleError* other); }; public: /* State specific to the kind of parse being performed. */ ParseHandler handler; void prepareNodeForMutation(Node node) { handler.prepareNodeForMutation(node); } void freeTree(Node node) { handler.freeTree(node); } public: Parser(ExclusiveContext* cx, LifoAlloc& alloc, const ReadOnlyCompileOptions& options, const char16_t* chars, size_t length, bool foldConstants, UsedNameTracker& usedNames, Parser* syntaxParser, LazyScript* lazyOuterFunction); ~Parser(); friend class AutoAwaitIsKeyword; void setAwaitIsKeyword(bool isKeyword); bool checkOptions(); // A Parser::Mark is the extension of the LifoAlloc::Mark to the entire // Parser's state. Note: clients must still take care that any ParseContext // that points into released ParseNodes is destroyed. class Mark { friend class Parser; LifoAlloc::Mark mark; ObjectBox* traceListHead; }; Mark mark() const { Mark m; m.mark = alloc.mark(); m.traceListHead = traceListHead; return m; } void release(Mark m) { alloc.release(m.mark); traceListHead = m.traceListHead; } friend void js::frontend::MarkParser(JSTracer* trc, JS::AutoGCRooter* parser); /* * Parse a top-level JS script. */ Node parse(); /* * Allocate a new parsed object or function container from * cx->tempLifoAlloc. */ ObjectBox* newObjectBox(JSObject* obj); FunctionBox* newFunctionBox(Node fn, JSFunction* fun, uint32_t toStringStart, Directives directives, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB); /* * Create a new function object given a name (which is optional if this is * a function expression). */ JSFunction* newFunction(HandleAtom atom, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, HandleObject proto); void trace(JSTracer* trc); private: Parser* thisForCtor() { return this; } JSAtom* stopStringCompression(); Node stringLiteral(); Node noSubstitutionTaggedTemplate(); Node noSubstitutionUntaggedTemplate(); Node templateLiteral(YieldHandling yieldHandling); bool taggedTemplate(YieldHandling yieldHandling, Node nodeList, TokenKind tt); bool appendToCallSiteObj(Node callSiteObj); bool addExprAndGetNextTemplStrToken(YieldHandling yieldHandling, Node nodeList, TokenKind* ttp); bool checkStatementsEOF(); inline Node newName(PropertyName* name); inline Node newName(PropertyName* name, TokenPos pos); inline Node newYieldExpression(uint32_t begin, Node expr, bool isYieldStar = false); inline Node newAwaitExpression(uint32_t begin, Node expr); inline bool abortIfSyntaxParser(); public: /* Public entry points for parsing. */ Node statement(YieldHandling yieldHandling); Node statementListItem(YieldHandling yieldHandling, bool canHaveDirectives = false); bool maybeParseDirective(Node list, Node pn, bool* cont); // Parse the body of an eval. // // Eval scripts are distinguished from global scripts in that in ES6, per // 18.2.1.1 steps 9 and 10, all eval scripts are executed under a fresh // lexical scope. Node evalBody(EvalSharedContext* evalsc); // Parse the body of a global script. Node globalBody(GlobalSharedContext* globalsc); // Parse a module. Node moduleBody(ModuleSharedContext* modulesc); // Parse a function, used for the Function, GeneratorFunction, and // AsyncFunction constructors. Node standaloneFunction(HandleFunction fun, HandleScope enclosingScope, mozilla::Maybe parameterListEnd, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, Directives inheritedDirectives, Directives* newDirectives); // Parse a function, given only its arguments and body. Used for lazily // parsed functions. Node standaloneLazyFunction(HandleFunction fun, bool strict, GeneratorKind generatorKind, FunctionAsyncKind asyncKind); // Parse an inner function given an enclosing ParseContext and a // FunctionBox for the inner function. bool innerFunction(Node pn, ParseContext* outerpc, FunctionBox* funbox, uint32_t toStringStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, Directives inheritedDirectives, Directives* newDirectives); // Parse a function's formal parameters and its body assuming its function // ParseContext is already on the stack. bool functionFormalParametersAndBody(InHandling inHandling, YieldHandling yieldHandling, Node pn, FunctionSyntaxKind kind, mozilla::Maybe parameterListEnd = mozilla::Nothing(), bool isStandaloneFunction = false); // Match the current token against the BindingIdentifier production with // the given Yield parameter. If there is no match, report a syntax // error. PropertyName* bindingIdentifier(YieldHandling yieldHandling); private: /* * JS parsers, from lowest to highest precedence. * * Each parser must be called during the dynamic scope of a ParseContext * object, pointed to by this->pc. * * Each returns a parse node tree or null on error. * * Parsers whose name has a '1' suffix leave the TokenStream state * pointing to the token one past the end of the parsed fragment. For a * number of the parsers this is convenient and avoids a lot of * unnecessary ungetting and regetting of tokens. * * Some parsers have two versions: an always-inlined version (with an 'i' * suffix) and a never-inlined version (with an 'n' suffix). */ Node functionStmt(uint32_t toStringStart, YieldHandling yieldHandling, DefaultHandling defaultHandling, FunctionAsyncKind asyncKind = SyncFunction); Node functionExpr(uint32_t toStringStart, InvokedPrediction invoked = PredictUninvoked, FunctionAsyncKind asyncKind = SyncFunction); Node statementList(YieldHandling yieldHandling); Node blockStatement(YieldHandling yieldHandling, unsigned errorNumber = JSMSG_CURLY_IN_COMPOUND); Node doWhileStatement(YieldHandling yieldHandling); Node whileStatement(YieldHandling yieldHandling); Node forStatement(YieldHandling yieldHandling); bool forHeadStart(YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInitialPart, mozilla::Maybe& forLetImpliedScope, Node* forInOrOfExpression); Node expressionAfterForInOrOf(ParseNodeKind forHeadKind, YieldHandling yieldHandling); Node switchStatement(YieldHandling yieldHandling); Node continueStatement(YieldHandling yieldHandling); Node breakStatement(YieldHandling yieldHandling); Node returnStatement(YieldHandling yieldHandling); Node withStatement(YieldHandling yieldHandling); Node throwStatement(YieldHandling yieldHandling); Node tryStatement(YieldHandling yieldHandling); Node catchBlockStatement(YieldHandling yieldHandling, ParseContext::Scope& catchParamScope); Node debuggerStatement(); Node variableStatement(YieldHandling yieldHandling); Node labeledStatement(YieldHandling yieldHandling); Node labeledItem(YieldHandling yieldHandling); Node ifStatement(YieldHandling yieldHandling); Node consequentOrAlternative(YieldHandling yieldHandling); // While on a |let| TOK_NAME token, examine |next|. Indicate whether // |next|, the next token already gotten with modifier TokenStream::None, // continues a LexicalDeclaration. bool nextTokenContinuesLetDeclaration(TokenKind next, YieldHandling yieldHandling); Node lexicalDeclaration(YieldHandling yieldHandling, DeclarationKind kind); Node importDeclaration(); bool processExport(Node node); bool processExportFrom(Node node); Node exportFrom(uint32_t begin, Node specList); Node exportBatch(uint32_t begin); bool checkLocalExportNames(Node node); Node exportClause(uint32_t begin); Node exportFunctionDeclaration(uint32_t begin); Node exportVariableStatement(uint32_t begin); Node exportClassDeclaration(uint32_t begin); Node exportLexicalDeclaration(uint32_t begin, DeclarationKind kind); Node exportDefaultFunctionDeclaration(uint32_t begin, FunctionAsyncKind asyncKind = SyncFunction); Node exportDefaultClassDeclaration(uint32_t begin); Node exportDefaultAssignExpr(uint32_t begin); Node exportDefault(uint32_t begin); Node exportDeclaration(); Node expressionStatement(YieldHandling yieldHandling, InvokedPrediction invoked = PredictUninvoked); // Declaration parsing. The main entrypoint is Parser::declarationList, // with sub-functionality split out into the remaining methods. // |blockScope| may be non-null only when |kind| corresponds to a lexical // declaration (that is, PNK_LET or PNK_CONST). // // The for* parameters, for normal declarations, should be null/ignored. // They should be non-null only when Parser::forHeadStart parses a // declaration at the start of a for-loop head. // // In this case, on success |*forHeadKind| is PNK_FORHEAD, PNK_FORIN, or // PNK_FOROF, corresponding to the three for-loop kinds. The precise value // indicates what was parsed. // // If parsing recognized a for(;;) loop, the next token is the ';' within // the loop-head that separates the init/test parts. // // Otherwise, for for-in/of loops, the next token is the ')' ending the // loop-head. Additionally, the expression that the loop iterates over was // parsed into |*forInOrOfExpression|. Node declarationList(YieldHandling yieldHandling, ParseNodeKind kind, ParseNodeKind* forHeadKind = nullptr, Node* forInOrOfExpression = nullptr); // The items in a declaration list are either patterns or names, with or // without initializers. These two methods parse a single pattern/name and // any associated initializer -- and if parsing an |initialDeclaration| // will, if parsing in a for-loop head (as specified by |forHeadKind| being // non-null), consume additional tokens up to the closing ')' in a // for-in/of loop head, returning the iterated expression in // |*forInOrOfExpression|. (An "initial declaration" is the first // declaration in a declaration list: |a| but not |b| in |var a, b|, |{c}| // but not |d| in |let {c} = 3, d|.) Node declarationPattern(Node decl, DeclarationKind declKind, TokenKind tt, bool initialDeclaration, YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInOrOfExpression); Node declarationName(Node decl, DeclarationKind declKind, TokenKind tt, bool initialDeclaration, YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInOrOfExpression); // Having parsed a name (not found in a destructuring pattern) declared by // a declaration, with the current token being the '=' separating the name // from its initializer, parse and bind that initializer -- and possibly // consume trailing in/of and subsequent expression, if so directed by // |forHeadKind|. bool initializerInNameDeclaration(Node decl, Node binding, Handle name, DeclarationKind declKind, bool initialDeclaration, YieldHandling yieldHandling, ParseNodeKind* forHeadKind, Node* forInOrOfExpression); Node expr(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError = nullptr, InvokedPrediction invoked = PredictUninvoked); Node assignExpr(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError = nullptr, InvokedPrediction invoked = PredictUninvoked); Node assignExprWithoutYieldOrAwait(YieldHandling yieldHandling); Node yieldExpression(InHandling inHandling); Node condExpr1(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError, InvokedPrediction invoked = PredictUninvoked); Node orExpr1(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError, InvokedPrediction invoked = PredictUninvoked); Node unaryExpr(YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError = nullptr, InvokedPrediction invoked = PredictUninvoked); Node memberExpr(YieldHandling yieldHandling, TripledotHandling tripledotHandling, TokenKind tt, bool allowCallSyntax = true, PossibleError* possibleError = nullptr, InvokedPrediction invoked = PredictUninvoked); Node primaryExpr(YieldHandling yieldHandling, TripledotHandling tripledotHandling, TokenKind tt, PossibleError* possibleError, InvokedPrediction invoked = PredictUninvoked); Node exprInParens(InHandling inHandling, YieldHandling yieldHandling, TripledotHandling tripledotHandling, PossibleError* possibleError = nullptr); bool tryNewTarget(Node& newTarget); bool checkAndMarkSuperScope(); Node methodDefinition(uint32_t toStringStart, PropertyType propType, HandleAtom funName); /* * Additional JS parsers. */ bool functionArguments(YieldHandling yieldHandling, FunctionSyntaxKind kind, Node funcpn); Node functionDefinition(uint32_t toStringStart, Node pn, InHandling inHandling, YieldHandling yieldHandling, HandleAtom name, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB = false); // Parse a function body. Pass StatementListBody if the body is a list of // statements; pass ExpressionBody if the body is a single expression. enum FunctionBodyType { StatementListBody, ExpressionBody }; Node functionBody(InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, FunctionBodyType type); Node unaryOpExpr(YieldHandling yieldHandling, ParseNodeKind kind, JSOp op, uint32_t begin); Node condition(InHandling inHandling, YieldHandling yieldHandling); /* comprehensions */ Node generatorComprehensionLambda(unsigned begin); Node comprehensionFor(GeneratorKind comprehensionKind); Node comprehensionIf(GeneratorKind comprehensionKind); Node comprehensionTail(GeneratorKind comprehensionKind); Node comprehension(GeneratorKind comprehensionKind); Node arrayComprehension(uint32_t begin); Node generatorComprehension(uint32_t begin); bool argumentList(YieldHandling yieldHandling, Node listNode, bool* isSpread, PossibleError* possibleError = nullptr); Node destructuringDeclaration(DeclarationKind kind, YieldHandling yieldHandling, TokenKind tt); Node destructuringDeclarationWithoutYieldOrAwait(DeclarationKind kind, YieldHandling yieldHandling, TokenKind tt); bool namedImportsOrNamespaceImport(TokenKind tt, Node importSpecSet); bool checkExportedName(JSAtom* exportName); bool checkExportedNamesForDeclaration(Node node); bool checkExportedNameForClause(Node node); bool checkExportedNameForFunction(Node node); bool checkExportedNameForClass(Node node); enum ClassContext { ClassStatement, ClassExpression }; Node classDefinition(YieldHandling yieldHandling, ClassContext classContext, DefaultHandling defaultHandling); bool checkLabelOrIdentifierReference(HandlePropertyName ident, uint32_t offset, YieldHandling yieldHandling); bool checkLocalExportName(HandlePropertyName ident, uint32_t offset) { return checkLabelOrIdentifierReference(ident, offset, YieldIsName); } bool checkBindingIdentifier(HandlePropertyName ident, uint32_t offset, YieldHandling yieldHandling); PropertyName* labelOrIdentifierReference(YieldHandling yieldHandling); PropertyName* labelIdentifier(YieldHandling yieldHandling) { return labelOrIdentifierReference(yieldHandling); } PropertyName* identifierReference(YieldHandling yieldHandling) { return labelOrIdentifierReference(yieldHandling); } PropertyName* importedBinding() { return bindingIdentifier(YieldIsName); } Node identifierReference(Handle name); bool matchLabel(YieldHandling yieldHandling, MutableHandle label); bool allowsForEachIn() { #if !JS_HAS_FOR_EACH_IN return false; #else return versionNumber() >= JSVERSION_1_6; #endif } bool matchInOrOf(bool* isForInp, bool* isForOfp); bool hasUsedFunctionSpecialName(HandlePropertyName name); bool declareFunctionArgumentsObject(); bool declareFunctionThis(); Node newInternalDotName(HandlePropertyName name); Node newThisName(); Node newDotGeneratorName(); bool declareDotGeneratorName(); bool skipLazyInnerFunction(Node pn, uint32_t toStringStart, FunctionSyntaxKind kind, bool tryAnnexB); bool innerFunction(Node pn, ParseContext* outerpc, HandleFunction fun, uint32_t toStringStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB, Directives inheritedDirectives, Directives* newDirectives); bool trySyntaxParseInnerFunction(Node pn, HandleFunction fun, uint32_t toStringStart, InHandling inHandling, YieldHandling yieldHandling, FunctionSyntaxKind kind, GeneratorKind generatorKind, FunctionAsyncKind asyncKind, bool tryAnnexB, Directives inheritedDirectives, Directives* newDirectives); bool finishFunctionScopes(bool isStandaloneFunction); bool finishFunction(bool isStandaloneFunction = false); bool leaveInnerFunction(ParseContext* outerpc); bool matchOrInsertSemicolonHelper(TokenStream::Modifier modifier); bool matchOrInsertSemicolonAfterExpression(); bool matchOrInsertSemicolonAfterNonExpression(); public: enum FunctionCallBehavior { PermitAssignmentToFunctionCalls, ForbidAssignmentToFunctionCalls }; bool isValidSimpleAssignmentTarget(Node node, FunctionCallBehavior behavior = ForbidAssignmentToFunctionCalls); private: bool checkIncDecOperand(Node operand, uint32_t operandOffset); bool checkStrictAssignment(Node lhs); bool hasValidSimpleStrictParameterNames(); void reportRedeclaration(HandlePropertyName name, DeclarationKind prevKind, TokenPos pos, uint32_t prevPos); bool notePositionalFormalParameter(Node fn, HandlePropertyName name, uint32_t beginPos, bool disallowDuplicateParams, bool* duplicatedParam); bool noteDestructuredPositionalFormalParameter(Node fn, Node destruct); mozilla::Maybe isVarRedeclaredInEval(HandlePropertyName name, DeclarationKind kind); bool tryDeclareVar(HandlePropertyName name, DeclarationKind kind, uint32_t beginPos, mozilla::Maybe* redeclaredKind, uint32_t* prevPos); bool tryDeclareVarForAnnexBLexicalFunction(HandlePropertyName name, uint32_t beginPos, bool* tryAnnexB); bool checkLexicalDeclarationDirectlyWithinBlock(ParseContext::Statement& stmt, DeclarationKind kind, TokenPos pos); bool noteDeclaredName(HandlePropertyName name, DeclarationKind kind, TokenPos pos); bool noteUsedName(HandlePropertyName name); bool hasUsedName(HandlePropertyName name); // Required on Scope exit. bool propagateFreeNamesAndMarkClosedOverBindings(ParseContext::Scope& scope); mozilla::Maybe newGlobalScopeData(ParseContext::Scope& scope); mozilla::Maybe newModuleScopeData(ParseContext::Scope& scope); mozilla::Maybe newEvalScopeData(ParseContext::Scope& scope); mozilla::Maybe newFunctionScopeData(ParseContext::Scope& scope, bool hasParameterExprs); mozilla::Maybe newVarScopeData(ParseContext::Scope& scope); mozilla::Maybe newLexicalScopeData(ParseContext::Scope& scope); Node finishLexicalScope(ParseContext::Scope& scope, Node body); Node propertyName(YieldHandling yieldHandling, Node propList, PropertyType* propType, MutableHandleAtom propAtom); Node computedPropertyName(YieldHandling yieldHandling, Node literal); Node arrayInitializer(YieldHandling yieldHandling, PossibleError* possibleError); Node newRegExp(); Node objectLiteral(YieldHandling yieldHandling, PossibleError* possibleError); // Top-level entrypoint into destructuring pattern checking/name-analyzing. bool checkDestructuringPattern(Node pattern, mozilla::Maybe maybeDecl, PossibleError* possibleError = nullptr); // Recursive methods for checking/name-analyzing subcomponents of a // destructuring pattern. The array/object methods *must* be passed arrays // or objects. The name method may be passed anything but will report an // error if not passed a name. bool checkDestructuringArray(Node arrayPattern, mozilla::Maybe maybeDecl); bool checkDestructuringObject(Node objectPattern, mozilla::Maybe maybeDecl); bool checkDestructuringName(Node expr, mozilla::Maybe maybeDecl); Node newNumber(const Token& tok) { return handler.newNumber(tok.number(), tok.decimalPoint(), tok.pos); } static Node null() { return ParseHandler::null(); } JSAtom* prefixAccessorName(PropertyType propType, HandleAtom propAtom); bool asmJS(Node list); }; template class MOZ_STACK_CLASS AutoAwaitIsKeyword { private: Parser* parser_; bool oldAwaitIsKeyword_; public: AutoAwaitIsKeyword(Parser* parser, bool awaitIsKeyword) { parser_ = parser; oldAwaitIsKeyword_ = parser_->awaitIsKeyword_; parser_->setAwaitIsKeyword(awaitIsKeyword); } ~AutoAwaitIsKeyword() { parser_->setAwaitIsKeyword(oldAwaitIsKeyword_); } }; } /* namespace frontend */ } /* namespace js */ #endif /* frontend_Parser_h */