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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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef jit_StackSlotAllocator_h
#define jit_StackSlotAllocator_h
#include "jit/Registers.h"
namespace js {
namespace jit {
class StackSlotAllocator {
js::Vector<uint32_t, 4, SystemAllocPolicy> normalSlots;
js::Vector<uint32_t, 4, SystemAllocPolicy> doubleSlots;
uint32_t height_;
void addAvailableSlot(uint32_t index) {
// Ignoring OOM here (and below) is fine; it just means the stack slot
// will be unused.
(void)normalSlots.append(index);
}
void addAvailableDoubleSlot(uint32_t index) {
(void)doubleSlots.append(index);
}
uint32_t allocateQuadSlot() {
// This relies on the fact that any architecture specific
// alignment of the stack pointer is done a priori.
if (height_ % 8 != 0) {
addAvailableSlot(height_ += 4);
}
if (height_ % 16 != 0) {
addAvailableDoubleSlot(height_ += 8);
}
return height_ += 16;
}
uint32_t allocateDoubleSlot() {
if (!doubleSlots.empty()) {
return doubleSlots.popCopy();
}
if (height_ % 8 != 0) {
addAvailableSlot(height_ += 4);
}
return height_ += 8;
}
uint32_t allocateSlot() {
if (!normalSlots.empty()) {
return normalSlots.popCopy();
}
if (!doubleSlots.empty()) {
uint32_t index = doubleSlots.popCopy();
addAvailableSlot(index - 4);
return index;
}
return height_ += 4;
}
public:
StackSlotAllocator() : height_(0) {}
void allocateStackArea(LStackArea* alloc) {
uint32_t size = alloc->size();
MOZ_ASSERT(size % 4 == 0);
switch (alloc->alignment()) {
case 8:
if ((height_ + size) % 8 != 0) {
addAvailableSlot(height_ += 4);
}
break;
default:
MOZ_CRASH("unexpected stack results area alignment");
}
MOZ_ASSERT((height_ + size) % alloc->alignment() == 0);
height_ += size;
alloc->setBase(height_);
}
static uint32_t width(LDefinition::Type type) {
switch (type) {
#if JS_BITS_PER_WORD == 32
case LDefinition::GENERAL:
case LDefinition::OBJECT:
case LDefinition::SLOTS:
case LDefinition::WASM_ANYREF:
#endif
#ifdef JS_NUNBOX32
case LDefinition::TYPE:
case LDefinition::PAYLOAD:
#endif
case LDefinition::INT32:
case LDefinition::FLOAT32:
return 4;
#if JS_BITS_PER_WORD == 64
case LDefinition::GENERAL:
case LDefinition::OBJECT:
case LDefinition::SLOTS:
case LDefinition::WASM_ANYREF:
#endif
#ifdef JS_PUNBOX64
case LDefinition::BOX:
#endif
case LDefinition::DOUBLE:
return 8;
case LDefinition::SIMD128:
return 16;
case LDefinition::STACKRESULTS:
MOZ_CRASH("Stack results area must be allocated manually");
}
MOZ_CRASH("Unknown slot type");
}
uint32_t allocateSlot(LDefinition::Type type) {
switch (width(type)) {
case 4:
return allocateSlot();
case 8:
return allocateDoubleSlot();
case 16:
return allocateQuadSlot();
}
MOZ_CRASH("Unknown slot width");
}
uint32_t stackHeight() const { return height_; }
};
} // namespace jit
} // namespace js
#endif /* jit_StackSlotAllocator_h */
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