Source/JavaScriptCore/b3/air/AirStackAllocation.h

/*
 * Copyright (C) 2017 Apple Inc. All rights reserved.
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#pragma once

#if ENABLE(B3_JIT)

#include <wtf/Vector.h>

namespace JSC { namespace B3 { namespace Air {

class Code;
class StackSlot;

// This is a collection of utilities shared by both stack allocators
// (allocateStackByGraphColoring and allocateRegistersAndStackByLinearScan).

// Attempt to put the given stack slot at the given offset. Returns false if this would cause
// the slot to overlap with any of the given slots.
bool attemptAssignment(StackSlot*, intptr_t offsetFromFP, const Vector<StackSlot*>& adjacent);

// Performs a first-fit assignment (smallest possible offset) of the given stack slot such that
// it does not overlap with any of the adjacent slots.
void assign(StackSlot*, const Vector<StackSlot*>& adjacent);

// Allocates all stack slots that escape - that is, that don't have live ranges that can be
// determined by looking at their uses. Returns a vector of slots that got assigned offsets.
// This assumes that no stack allocation has happened previously, and so frame size is zero.
Vector<StackSlot*> allocateAndGetEscapedStackSlotsWithoutChangingFrameSize(Code&);

// Same as allocateAndGetEscapedStackSlotsWithoutChangingFrameSize, but does not return the
// assigned slots, and does set the frame size based on the largest extent of any of the
// allocated slots.
void allocateEscapedStackSlots(Code&);

// Updates Code::frameSize based on the largest extent of any stack slot. This is useful to
// call after performing stack allocation.
void updateFrameSizeBasedOnStackSlots(Code&);

} } } // namespace JSC::B3::Air

#endif // ENABLE(B3_JIT)