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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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 "mozilla/Unused.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.
+ mozilla::Unused << normalSlots.append(index);
+ }
+ void addAvailableDoubleSlot(uint32_t index) {
+ mozilla::Unused << doubleSlots.append(index);
+ }
+
+ uint32_t allocateQuadSlot() {
+ MOZ_ASSERT(SupportsSimd);
+ // 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)
+ { }
+
+ static uint32_t width(LDefinition::Type type) {
+ switch (type) {
+#if JS_BITS_PER_WORD == 32
+ case LDefinition::GENERAL:
+ case LDefinition::OBJECT:
+ case LDefinition::SLOTS:
+#endif
+ case LDefinition::INT32:
+ case LDefinition::FLOAT32: return 4;
+#if JS_BITS_PER_WORD == 64
+ case LDefinition::GENERAL:
+ case LDefinition::OBJECT:
+ case LDefinition::SLOTS:
+#endif
+#ifdef JS_PUNBOX64
+ case LDefinition::BOX:
+#endif
+#ifdef JS_NUNBOX32
+ case LDefinition::TYPE:
+ case LDefinition::PAYLOAD:
+#endif
+ case LDefinition::DOUBLE: return 8;
+ case LDefinition::SINCOS:
+ case LDefinition::SIMD128INT:
+ case LDefinition::SIMD128FLOAT: return 16;
+ }
+ 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 */