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/* -*- 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
#include "frontend/PropOpEmitter.h"
#include "frontend/BytecodeEmitter.h"
#include "frontend/ParserAtom.h" // ParserAtom
#include "frontend/SharedContext.h"
#include "vm/Opcodes.h"
#include "vm/ThrowMsgKind.h" // ThrowMsgKind
using namespace js;
using namespace js::frontend;
PropOpEmitter::PropOpEmitter(BytecodeEmitter* bce, Kind kind, ObjKind objKind)
: bce_(bce), kind_(kind), objKind_(objKind) {}
bool PropOpEmitter::prepareAtomIndex(TaggedParserAtomIndex prop) {
return bce_->makeAtomIndex(prop, ParserAtom::Atomize::Yes, &propAtomIndex_);
}
bool PropOpEmitter::prepareForObj() {
MOZ_ASSERT(state_ == State::Start);
#ifdef DEBUG
state_ = State::Obj;
#endif
return true;
}
bool PropOpEmitter::emitGet(TaggedParserAtomIndex prop) {
MOZ_ASSERT(state_ == State::Obj);
if (!prepareAtomIndex(prop)) {
return false;
}
if (isCall()) {
if (!bce_->emit1(JSOp::Dup)) {
// [stack] # if Super
// [stack] THIS THIS
// [stack] # otherwise
// [stack] OBJ OBJ
return false;
}
}
if (isSuper()) {
if (!bce_->emitSuperBase()) {
// [stack] THIS? THIS SUPERBASE
return false;
}
}
if (isIncDec() || isCompoundAssignment()) {
if (isSuper()) {
if (!bce_->emit1(JSOp::Dup2)) {
// [stack] THIS SUPERBASE THIS SUPERBASE
return false;
}
} else {
if (!bce_->emit1(JSOp::Dup)) {
// [stack] OBJ OBJ
return false;
}
}
}
JSOp op = isSuper() ? JSOp::GetPropSuper : JSOp::GetProp;
if (!bce_->emitAtomOp(op, propAtomIndex_)) {
// [stack] # if Get
// [stack] PROP
// [stack] # if Call
// [stack] THIS PROP
// [stack] # if Inc/Dec/Compound, Super]
// [stack] THIS SUPERBASE PROP
// [stack] # if Inc/Dec/Compound, other
// [stack] OBJ PROP
return false;
}
if (isCall()) {
if (!bce_->emit1(JSOp::Swap)) {
// [stack] PROP THIS
return false;
}
}
#ifdef DEBUG
state_ = State::Get;
#endif
return true;
}
bool PropOpEmitter::prepareForRhs() {
MOZ_ASSERT(isSimpleAssignment() || isPropInit() || isCompoundAssignment());
MOZ_ASSERT_IF(isSimpleAssignment() || isPropInit(), state_ == State::Obj);
MOZ_ASSERT_IF(isCompoundAssignment(), state_ == State::Get);
if (isSimpleAssignment() || isPropInit()) {
// For CompoundAssignment, SuperBase is already emitted by emitGet.
if (isSuper()) {
if (!bce_->emitSuperBase()) {
// [stack] THIS SUPERBASE
return false;
}
}
}
#ifdef DEBUG
state_ = State::Rhs;
#endif
return true;
}
bool PropOpEmitter::skipObjAndRhs() {
MOZ_ASSERT(state_ == State::Start);
MOZ_ASSERT(isSimpleAssignment() || isPropInit());
#ifdef DEBUG
state_ = State::Rhs;
#endif
return true;
}
bool PropOpEmitter::emitDelete(TaggedParserAtomIndex prop) {
MOZ_ASSERT_IF(!isSuper(), state_ == State::Obj);
MOZ_ASSERT_IF(isSuper(), state_ == State::Start);
MOZ_ASSERT(isDelete());
if (!prepareAtomIndex(prop)) {
return false;
}
if (isSuper()) {
if (!bce_->emitSuperBase()) {
// [stack] THIS SUPERBASE
return false;
}
// Unconditionally throw when attempting to delete a super-reference.
if (!bce_->emit2(JSOp::ThrowMsg, uint8_t(ThrowMsgKind::CantDeleteSuper))) {
// [stack] THIS SUPERBASE
return false;
}
// Another wrinkle: Balance the stack from the emitter's point of view.
// Execution will not reach here, as the last bytecode threw.
if (!bce_->emit1(JSOp::Pop)) {
// [stack] THIS
return false;
}
} else {
JSOp op = bce_->sc->strict() ? JSOp::StrictDelProp : JSOp::DelProp;
if (!bce_->emitAtomOp(op, propAtomIndex_)) {
// [stack] SUCCEEDED
return false;
}
}
#ifdef DEBUG
state_ = State::Delete;
#endif
return true;
}
bool PropOpEmitter::emitAssignment(TaggedParserAtomIndex prop) {
MOZ_ASSERT(isSimpleAssignment() || isPropInit() || isCompoundAssignment());
MOZ_ASSERT(state_ == State::Rhs);
if (isSimpleAssignment() || isPropInit()) {
if (!prepareAtomIndex(prop)) {
return false;
}
}
MOZ_ASSERT_IF(isPropInit(), !isSuper());
JSOp setOp = isPropInit() ? JSOp::InitProp
: isSuper() ? bce_->sc->strict() ? JSOp::StrictSetPropSuper
: JSOp::SetPropSuper
: bce_->sc->strict() ? JSOp::StrictSetProp
: JSOp::SetProp;
if (!bce_->emitAtomOp(setOp, propAtomIndex_)) {
// [stack] VAL
return false;
}
#ifdef DEBUG
state_ = State::Assignment;
#endif
return true;
}
bool PropOpEmitter::emitIncDec(TaggedParserAtomIndex prop,
ValueUsage valueUsage) {
MOZ_ASSERT(state_ == State::Obj);
MOZ_ASSERT(isIncDec());
if (!emitGet(prop)) {
return false;
}
MOZ_ASSERT(state_ == State::Get);
JSOp incOp = isInc() ? JSOp::Inc : JSOp::Dec;
if (!bce_->emit1(JSOp::ToNumeric)) {
// [stack] ... N
return false;
}
if (isPostIncDec() && valueUsage == ValueUsage::WantValue) {
// [stack] OBJ SUPERBASE? N
if (!bce_->emit1(JSOp::Dup)) {
// [stack] .. N N
return false;
}
if (!bce_->emit2(JSOp::Unpick, 2 + isSuper())) {
// [stack] N OBJ SUPERBASE? N
return false;
}
}
if (!bce_->emit1(incOp)) {
// [stack] ... N+1
return false;
}
JSOp setOp = isSuper() ? bce_->sc->strict() ? JSOp::StrictSetPropSuper
: JSOp::SetPropSuper
: bce_->sc->strict() ? JSOp::StrictSetProp
: JSOp::SetProp;
if (!bce_->emitAtomOp(setOp, propAtomIndex_)) {
// [stack] N? N+1
return false;
}
if (isPostIncDec() && valueUsage == ValueUsage::WantValue) {
if (!bce_->emit1(JSOp::Pop)) {
// [stack] N
return false;
}
}
#ifdef DEBUG
state_ = State::IncDec;
#endif
return true;
}