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| -rw-r--r-- | js/src/frontend/FunctionEmitter.h | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/js/src/frontend/FunctionEmitter.h b/js/src/frontend/FunctionEmitter.h new file mode 100644 index 0000000000..b36f223664 --- /dev/null +++ b/js/src/frontend/FunctionEmitter.h @@ -0,0 +1,436 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef frontend_FunctionEmitter_h +#define frontend_FunctionEmitter_h + +#include "mozilla/Attributes.h" // MOZ_STACK_CLASS + +#include <stdint.h> // uint16_t, uint32_t + +#include "frontend/AsyncEmitter.h" // AsyncEmitter +#include "frontend/DefaultEmitter.h" // DefaultEmitter +#include "frontend/EmitterScope.h" // EmitterScope +#include "frontend/FunctionSyntaxKind.h" // FunctionSyntaxKind +#include "frontend/ParserAtom.h" // TaggedParserAtomIndex +#include "frontend/TDZCheckCache.h" // TDZCheckCache + +namespace js { + +class GCThingIndex; + +namespace frontend { + +struct BytecodeEmitter; +class FunctionBox; + +// Class for emitting function declaration, expression, or method etc. +// +// This class handles the enclosing script's part (function object creation, +// declaration, etc). The content of the function script is handled by +// FunctionScriptEmitter and FunctionParamsEmitter. +// +// Usage: (check for the return value is omitted for simplicity) +// +// `function f() {}`, non lazy script +// FunctionEmitter fe(this, funbox_for_f, FunctionSyntaxKind::Statement, +// FunctionEmitter::IsHoisted::No); +// fe.prepareForNonLazy(); +// +// // Emit script with FunctionScriptEmitter here. +// ... +// +// fe.emitNonLazyEnd(); +// +// `function f() {}`, lazy script +// FunctionEmitter fe(this, funbox_for_f, FunctionSyntaxKind::Statement, +// FunctionEmitter::IsHoisted::No); +// fe.emitLazy(); +// +// `function f() {}`, emitting hoisted function again +// // See emitAgain comment for more details +// FunctionEmitter fe(this, funbox_for_f, FunctionSyntaxKind::Statement, +// FunctionEmitter::IsHoisted::Yes); +// fe.emitAgain(); +// +// `function f() { "use asm"; }` +// FunctionEmitter fe(this, funbox_for_f, FunctionSyntaxKind::Statement, +// FunctionEmitter::IsHoisted::No); +// fe.emitAsmJSModule(); +// +class MOZ_STACK_CLASS FunctionEmitter { + public: + enum class IsHoisted { No, Yes }; + + private: + BytecodeEmitter* bce_; + + FunctionBox* funbox_; + + // Function's explicit name. + TaggedParserAtomIndex name_; + + FunctionSyntaxKind syntaxKind_; + IsHoisted isHoisted_; + +#ifdef DEBUG + // The state of this emitter. + // + // +-------+ + // | Start |-+ + // +-------+ | + // | + // +-------+ + // | + // | [non-lazy function] + // | prepareForNonLazy +---------+ emitNonLazyEnd +-----+ + // +--------------------->| NonLazy |---------------->+->| End | + // | +---------+ ^ +-----+ + // | | + // | [lazy function] | + // | emitLazy | + // +------------------------------------------------->+ + // | ^ + // | [emitting hoisted function again] | + // | emitAgain | + // +------------------------------------------------->+ + // | ^ + // | [asm.js module] | + // | emitAsmJSModule | + // +--------------------------------------------------+ + // + enum class State { + // The initial state. + Start, + + // After calling prepareForNonLazy. + NonLazy, + + // After calling emitNonLazyEnd, emitLazy, emitAgain, or emitAsmJSModule. + End + }; + State state_ = State::Start; +#endif + + public: + FunctionEmitter(BytecodeEmitter* bce, FunctionBox* funbox, + FunctionSyntaxKind syntaxKind, IsHoisted isHoisted); + + [[nodiscard]] bool prepareForNonLazy(); + [[nodiscard]] bool emitNonLazyEnd(); + + [[nodiscard]] bool emitLazy(); + + [[nodiscard]] bool emitAgain(); + + [[nodiscard]] bool emitAsmJSModule(); + + private: + // Emit the function declaration, expression, method etc. + // This leaves function object on the stack for expression etc, + // and doesn't for declaration. + [[nodiscard]] bool emitFunction(); + + // Helper methods used by emitFunction for each case. + // `index` is the object index of the function. + [[nodiscard]] bool emitNonHoisted(GCThingIndex index); + [[nodiscard]] bool emitHoisted(GCThingIndex index); + [[nodiscard]] bool emitTopLevelFunction(GCThingIndex index); +}; + +// Class for emitting function script. +// Parameters are handled by FunctionParamsEmitter. +// +// Usage: (check for the return value is omitted for simplicity) +// +// `function f(a) { expr }` +// FunctionScriptEmitter fse(this, funbox_for_f, +// Some(offset_of_opening_paren), +// Some(offset_of_closing_brace)); +// fse.prepareForParameters(); +// +// // Emit parameters with FunctionParamsEmitter here. +// ... +// +// fse.prepareForBody(); +// emit(expr); +// fse.emitEnd(); +// +// // Do NameFunctions operation here if needed. +// +// fse.intoStencil(); +// +class MOZ_STACK_CLASS FunctionScriptEmitter { + private: + BytecodeEmitter* bce_; + + FunctionBox* funbox_; + + // Scope for the function name for a named lambda. + // None for anonymous function. + mozilla::Maybe<EmitterScope> namedLambdaEmitterScope_; + + // Scope for function body. + mozilla::Maybe<EmitterScope> functionEmitterScope_; + + // Scope for the extra body var. + // None if `funbox_->hasExtraBodyVarScope() == false`. + mozilla::Maybe<EmitterScope> extraBodyVarEmitterScope_; + + mozilla::Maybe<TDZCheckCache> tdzCache_; + + // try-catch block for async function parameter and body. + mozilla::Maybe<AsyncEmitter> asyncEmitter_; + + // See the comment for constructor. + mozilla::Maybe<uint32_t> paramStart_; + mozilla::Maybe<uint32_t> bodyEnd_; + +#ifdef DEBUG + // The state of this emitter. + // + // +-------+ prepareForParameters +------------+ + // | Start |---------------------->| Parameters |-+ + // +-------+ +------------+ | + // | + // +--------------------------------------------+ + // | + // | prepareForBody +------+ emitEndBody +---------+ + // +---------------->| Body |------------->| EndBody |-+ + // +------+ +---------+ | + // | + // +-------------------------------------------------+ + // | + // | intoStencil +-----+ + // +------------>| End | + // +-----+ + enum class State { + // The initial state. + Start, + + // After calling prepareForParameters. + Parameters, + + // After calling prepareForBody. + Body, + + // After calling emitEndBody. + EndBody, + + // After calling intoStencil. + End + }; + State state_ = State::Start; +#endif + + public: + // Parameters are the offset in the source code for each character below: + // + // function f(a, b, ...c) { ... } + // ^ ^ + // | | + // paramStart bodyEnd + // + // Can be Nothing() if not available. + FunctionScriptEmitter(BytecodeEmitter* bce, FunctionBox* funbox, + const mozilla::Maybe<uint32_t>& paramStart, + const mozilla::Maybe<uint32_t>& bodyEnd) + : bce_(bce), + funbox_(funbox), + paramStart_(paramStart), + bodyEnd_(bodyEnd) {} + + [[nodiscard]] bool prepareForParameters(); + [[nodiscard]] bool prepareForBody(); + [[nodiscard]] bool emitEndBody(); + + // Generate the ScriptStencil using the bytecode emitter data. + [[nodiscard]] bool intoStencil(); + + private: + [[nodiscard]] bool emitExtraBodyVarScope(); + [[nodiscard]] bool emitInitializeClosedOverArgumentBindings(); +}; + +// Class for emitting function parameters. +// +// Usage: (check for the return value is omitted for simplicity) +// +// `function f(a, b=10, ...c) {}` +// FunctionParamsEmitter fpe(this, funbox_for_f); +// +// fpe.emitSimple(atom_of_a); +// +// fpe.prepareForDefault(); +// emit(10); +// fpe.emitDefaultEnd(atom_of_b); +// +// fpe.emitRest(atom_of_c); +// +// `function f([a], [b]=[1], ...[c]) {}` +// FunctionParamsEmitter fpe(this, funbox_for_f); +// +// fpe.prepareForDestructuring(); +// emit(destructuring_for_[a]); +// fpe.emitDestructuringEnd(); +// +// fpe.prepareForDestructuringDefaultInitializer(); +// emit([1]); +// fpe.prepareForDestructuringDefault(); +// emit(destructuring_for_[b]); +// fpe.emitDestructuringDefaultEnd(); +// +// fpe.prepareForDestructuringRest(); +// emit(destructuring_for_[c]); +// fpe.emitDestructuringRestEnd(); +// +class MOZ_STACK_CLASS FunctionParamsEmitter { + private: + BytecodeEmitter* bce_; + + FunctionBox* funbox_; + + // The pointer to `FunctionScriptEmitter::functionEmitterScope_`, + // passed via `BytecodeEmitter::innermostEmitterScope()`. + EmitterScope* functionEmitterScope_; + + // The slot for the current parameter. + // NOTE: after emitting rest parameter, this isn't incremented. + uint16_t argSlot_ = 0; + + // DefaultEmitter for default parameter. + mozilla::Maybe<DefaultEmitter> default_; + +#ifdef DEBUG + // The state of this emitter. + // + // +----------------------------------------------------------+ + // | | + // | +-------+ | + // +->| Start |-+ | + // +-------+ | | + // | | + // +------------+ | + // | | + // | [single binding, without default] | + // | emitSimple | + // +--------------------------------------------------------->+ + // | ^ + // | [single binding, with default] | + // | prepareForDefault +---------+ emitDefaultEnd | + // +--------------------->| Default |------------------------>+ + // | +---------+ ^ + // | | + // | [destructuring, without default] | + // | prepareForDestructuring +---------------+ | + // +--------------------------->| Destructuring |-+ | + // | +---------------+ | | + // | | | + // | +-----------------------------------------+ | + // | | | + // | | emitDestructuringEnd | + // | +---------------------------------------------------->+ + // | ^ + // | [destructuring, with default] | + // | prepareForDestructuringDefaultInitializer | + // +---------------------------------------------+ | + // | | | + // | +----------------------------------------+ | + // | | | + // | | +---------------------------------+ | + // | +->| DestructuringDefaultInitializer |-+ | + // | +---------------------------------+ | | + // | | | + // | +------------------------------------+ | + // | | | + // | | prepareForDestructuringDefault | + // | +-------------------------------+ | + // | | | + // | +-----------------------------+ | + // | | | + // | | +----------------------+ | + // | +->| DestructuringDefault |-+ | + // | +----------------------+ | | + // | | | + // | +-------------------------+ | + // | | | + // | | emitDestructuringDefaultEnd | + // | +---------------------------------------------->+ + // | + // | [single binding rest] + // | emitRest +-----+ + // +--------------------------------------------------------->+->| End | + // | ^ +-----+ + // | [destructuring rest] | + // | prepareForDestructuringRest +-------------------+ | + // +-------------------------------->| DestructuringRest |-+ | + // +-------------------+ | | + // | | + // +----------------------------------------------------+ | + // | | + // | emitDestructuringRestEnd | + // +-------------------------------------------------------+ + // + enum class State { + // The initial state, or after emitting non-rest parameter. + Start, + + // After calling prepareForDefault. + Default, + + // After calling prepareForDestructuring. + Destructuring, + + // After calling prepareForDestructuringDefaultInitializer. + DestructuringDefaultInitializer, + + // After calling prepareForDestructuringDefault. + DestructuringDefault, + + // After calling prepareForDestructuringRest. + DestructuringRest, + + // After calling emitRest or emitDestructuringRestEnd. + End, + }; + State state_ = State::Start; +#endif + + public: + FunctionParamsEmitter(BytecodeEmitter* bce, FunctionBox* funbox); + + // paramName is used only when there's at least one expression in the + // paramerters (funbox_->hasParameterExprs == true). + [[nodiscard]] bool emitSimple(TaggedParserAtomIndex paramName); + + [[nodiscard]] bool prepareForDefault(); + [[nodiscard]] bool emitDefaultEnd(TaggedParserAtomIndex paramName); + + [[nodiscard]] bool prepareForDestructuring(); + [[nodiscard]] bool emitDestructuringEnd(); + + [[nodiscard]] bool prepareForDestructuringDefaultInitializer(); + [[nodiscard]] bool prepareForDestructuringDefault(); + [[nodiscard]] bool emitDestructuringDefaultEnd(); + + [[nodiscard]] bool emitRest(TaggedParserAtomIndex paramName); + + [[nodiscard]] bool prepareForDestructuringRest(); + [[nodiscard]] bool emitDestructuringRestEnd(); + + private: + [[nodiscard]] bool prepareForInitializer(); + [[nodiscard]] bool emitInitializerEnd(); + + [[nodiscard]] bool emitRestArray(); + + [[nodiscard]] bool emitAssignment(TaggedParserAtomIndex paramName); +}; + +} /* namespace frontend */ +} /* namespace js */ + +#endif /* frontend_FunctionEmitter_h */ |