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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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_BytecodeControlStructures_h
#define frontend_BytecodeControlStructures_h
#include "mozilla/Attributes.h"
#include <stddef.h>
#include <stdint.h>
#include "ds/Nestable.h"
#include "frontend/JumpList.h"
#include "frontend/SharedContext.h"
#include "frontend/TDZCheckCache.h"
#include "gc/Rooting.h"
#include "vm/String.h"
namespace js {
namespace frontend {
struct BytecodeEmitter;
class EmitterScope;
class NestableControl : public Nestable<NestableControl>
{
StatementKind kind_;
// The innermost scope when this was pushed.
EmitterScope* emitterScope_;
protected:
NestableControl(BytecodeEmitter* bce, StatementKind kind);
public:
using Nestable<NestableControl>::enclosing;
using Nestable<NestableControl>::findNearest;
StatementKind kind() const {
return kind_;
}
EmitterScope* emitterScope() const {
return emitterScope_;
}
template <typename T>
bool is() const;
template <typename T>
T& as() {
MOZ_ASSERT(this->is<T>());
return static_cast<T&>(*this);
}
};
class BreakableControl : public NestableControl
{
public:
// Offset of the last break.
JumpList breaks;
BreakableControl(BytecodeEmitter* bce, StatementKind kind);
MOZ_MUST_USE bool patchBreaks(BytecodeEmitter* bce);
};
template <>
inline bool
NestableControl::is<BreakableControl>() const
{
return StatementKindIsUnlabeledBreakTarget(kind_) || kind_ == StatementKind::Label;
}
class LabelControl : public BreakableControl
{
RootedAtom label_;
// The code offset when this was pushed. Used for effectfulness checking.
ptrdiff_t startOffset_;
public:
LabelControl(BytecodeEmitter* bce, JSAtom* label, ptrdiff_t startOffset);
HandleAtom label() const {
return label_;
}
ptrdiff_t startOffset() const {
return startOffset_;
}
};
template <>
inline bool
NestableControl::is<LabelControl>() const
{
return kind_ == StatementKind::Label;
}
class LoopControl : public BreakableControl
{
// Loops' children are emitted in dominance order, so they can always
// have a TDZCheckCache.
TDZCheckCache tdzCache_;
// Stack depth when this loop was pushed on the control stack.
int32_t stackDepth_;
// The loop nesting depth. Used as a hint to Ion.
uint32_t loopDepth_;
// Can we OSR into Ion from here? True unless there is non-loop state on the stack.
bool canIonOsr_;
public:
// The target of continue statement jumps, e.g., the update portion of a
// for(;;) loop.
JumpTarget continueTarget;
// Offset of the last continue in the loop.
JumpList continues;
LoopControl(BytecodeEmitter* bce, StatementKind loopKind);
uint32_t loopDepth() const {
return loopDepth_;
}
bool canIonOsr() const {
return canIonOsr_;
}
MOZ_MUST_USE bool patchBreaksAndContinues(BytecodeEmitter* bce);
};
template <>
inline bool
NestableControl::is<LoopControl>() const
{
return StatementKindIsLoop(kind_);
}
class TryFinallyControl : public NestableControl
{
bool emittingSubroutine_;
public:
// The subroutine when emitting a finally block.
JumpList gosubs;
// Offset of the last catch guard, if any.
JumpList guardJump;
TryFinallyControl(BytecodeEmitter* bce, StatementKind kind);
void setEmittingSubroutine() {
emittingSubroutine_ = true;
}
bool emittingSubroutine() const {
return emittingSubroutine_;
}
};
template <>
inline bool
NestableControl::is<TryFinallyControl>() const
{
return kind_ == StatementKind::Try || kind_ == StatementKind::Finally;
}
} /* namespace frontend */
} /* namespace js */
#endif /* frontend_BytecodeControlStructures_h */
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