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Diffstat (limited to 'js/src/frontend/ElemOpEmitter.cpp')
| -rw-r--r-- | js/src/frontend/ElemOpEmitter.cpp | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/js/src/frontend/ElemOpEmitter.cpp b/js/src/frontend/ElemOpEmitter.cpp new file mode 100644 index 0000000000..0d563e466d --- /dev/null +++ b/js/src/frontend/ElemOpEmitter.cpp @@ -0,0 +1,257 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "frontend/ElemOpEmitter.h" + +#include "frontend/BytecodeEmitter.h" +#include "frontend/SharedContext.h" +#include "vm/Opcodes.h" +#include "vm/ThrowMsgKind.h" // ThrowMsgKind + +using namespace js; +using namespace js::frontend; + +ElemOpEmitter::ElemOpEmitter(BytecodeEmitter* bce, Kind kind, ObjKind objKind) + : bce_(bce), kind_(kind), objKind_(objKind) {} + +bool ElemOpEmitter::prepareForObj() { + MOZ_ASSERT(state_ == State::Start); + +#ifdef DEBUG + state_ = State::Obj; +#endif + return true; +} + +bool ElemOpEmitter::prepareForKey() { + MOZ_ASSERT(state_ == State::Obj); + + if (isCall()) { + if (!bce_->emit1(JSOp::Dup)) { + // [stack] # if Super + // [stack] THIS THIS + // [stack] # otherwise + // [stack] OBJ OBJ + return false; + } + } + +#ifdef DEBUG + state_ = State::Key; +#endif + return true; +} + +bool ElemOpEmitter::emitGet() { + MOZ_ASSERT(state_ == State::Key); + + // Inc/dec and compound assignment use the KEY twice, but if it's an object, + // it must be converted ToPropertyKey only once, per spec. + if (isIncDec() || isCompoundAssignment()) { + if (!bce_->emit1(JSOp::ToPropertyKey)) { + // [stack] # if Super + // [stack] THIS KEY + // [stack] # otherwise + // [stack] OBJ KEY + return false; + } + } + + if (isSuper()) { + if (!bce_->emitSuperBase()) { + // [stack] THIS? THIS KEY SUPERBASE + return false; + } + } + if (isIncDec() || isCompoundAssignment()) { + if (isSuper()) { + if (!bce_->emitDupAt(2, 3)) { + // [stack] THIS KEY SUPERBASE THIS KEY SUPERBASE + return false; + } + } else { + if (!bce_->emit1(JSOp::Dup2)) { + // [stack] OBJ KEY OBJ KEY + return false; + } + } + } + + JSOp op; + if (isSuper()) { + op = JSOp::GetElemSuper; + } else { + op = JSOp::GetElem; + } + if (!bce_->emitElemOpBase(op)) { + // [stack] # if Get + // [stack] ELEM + // [stack] # if Call + // [stack] THIS ELEM + // [stack] # if Inc/Dec/Assignment, with Super + // [stack] THIS KEY SUPERBASE ELEM + // [stack] # if Inc/Dec/Assignment, other + // [stack] OBJ KEY ELEM + return false; + } + if (isCall()) { + if (!bce_->emit1(JSOp::Swap)) { + // [stack] ELEM THIS + return false; + } + } + +#ifdef DEBUG + state_ = State::Get; +#endif + return true; +} + +bool ElemOpEmitter::prepareForRhs() { + MOZ_ASSERT(isSimpleAssignment() || isPropInit() || isCompoundAssignment()); + MOZ_ASSERT_IF(isSimpleAssignment() || isPropInit(), state_ == State::Key); + 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 KEY SUPERBASE + return false; + } + } + } + +#ifdef DEBUG + state_ = State::Rhs; +#endif + return true; +} + +bool ElemOpEmitter::skipObjAndKeyAndRhs() { + MOZ_ASSERT(state_ == State::Start); + MOZ_ASSERT(isSimpleAssignment() || isPropInit()); + +#ifdef DEBUG + state_ = State::Rhs; +#endif + return true; +} + +bool ElemOpEmitter::emitDelete() { + MOZ_ASSERT(state_ == State::Key); + MOZ_ASSERT(isDelete()); + + if (isSuper()) { + if (!bce_->emit1(JSOp::ToPropertyKey)) { + // [stack] THIS KEY + return false; + } + if (!bce_->emitSuperBase()) { + // [stack] THIS KEY SUPERBASE + return false; + } + + // Unconditionally throw when attempting to delete a super-reference. + if (!bce_->emit2(JSOp::ThrowMsg, uint8_t(ThrowMsgKind::CantDeleteSuper))) { + // [stack] THIS KEY 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_->emitPopN(2)) { + // [stack] THIS + return false; + } + } else { + JSOp op = bce_->sc->strict() ? JSOp::StrictDelElem : JSOp::DelElem; + if (!bce_->emitElemOpBase(op)) { + // SUCCEEDED + return false; + } + } + +#ifdef DEBUG + state_ = State::Delete; +#endif + return true; +} + +bool ElemOpEmitter::emitAssignment() { + MOZ_ASSERT(isSimpleAssignment() || isPropInit() || isCompoundAssignment()); + MOZ_ASSERT(state_ == State::Rhs); + + MOZ_ASSERT_IF(isPropInit(), !isSuper()); + + JSOp setOp = isPropInit() ? JSOp::InitElem + : isSuper() ? bce_->sc->strict() ? JSOp::StrictSetElemSuper + : JSOp::SetElemSuper + : bce_->sc->strict() ? JSOp::StrictSetElem + : JSOp::SetElem; + if (!bce_->emitElemOpBase(setOp)) { + // [stack] ELEM + return false; + } + +#ifdef DEBUG + state_ = State::Assignment; +#endif + return true; +} + +bool ElemOpEmitter::emitIncDec(ValueUsage valueUsage) { + MOZ_ASSERT(state_ == State::Key); + MOZ_ASSERT(isIncDec()); + + if (!emitGet()) { + // [stack] ... ELEM + 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 KEY SUPERBASE? N + if (!bce_->emit1(JSOp::Dup)) { + // [stack] ... N N + return false; + } + if (!bce_->emit2(JSOp::Unpick, 3 + isSuper())) { + // [stack] N OBJ KEY SUPERBASE? N + return false; + } + } + if (!bce_->emit1(incOp)) { + // [stack] ... N+1 + return false; + } + + JSOp setOp = + isSuper() + ? (bce_->sc->strict() ? JSOp::StrictSetElemSuper : JSOp::SetElemSuper) + : (bce_->sc->strict() ? JSOp::StrictSetElem : JSOp::SetElem); + if (!bce_->emitElemOpBase(setOp)) { + // [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; +} |