diff -r 000000000000 -r 6474c204b198 js/src/jit/LIR.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit/LIR.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,1678 @@
+/* -*- 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_LIR_h
+#define jit_LIR_h
+
+// This file declares the core data structures for LIR: storage allocations for
+// inputs and outputs, as well as the interface instructions must conform to.
+
+#include "mozilla/Array.h"
+
+#include "jit/Bailouts.h"
+#include "jit/InlineList.h"
+#include "jit/IonAllocPolicy.h"
+#include "jit/LOpcodes.h"
+#include "jit/MIR.h"
+#include "jit/MIRGraph.h"
+#include "jit/Registers.h"
+#include "jit/Safepoints.h"
+
+namespace js {
+namespace jit {
+
+class LUse;
+class LGeneralReg;
+class LFloatReg;
+class LStackSlot;
+class LArgument;
+class LConstantIndex;
+class MBasicBlock;
+class MTableSwitch;
+class MIRGenerator;
+class MSnapshot;
+
+static const uint32_t VREG_INCREMENT = 1;
+
+static const uint32_t THIS_FRAME_ARGSLOT = 0;
+
+#if defined(JS_NUNBOX32)
+# define BOX_PIECES         2
+static const uint32_t VREG_TYPE_OFFSET = 0;
+static const uint32_t VREG_DATA_OFFSET = 1;
+static const uint32_t TYPE_INDEX = 0;
+static const uint32_t PAYLOAD_INDEX = 1;
+#elif defined(JS_PUNBOX64)
+# define BOX_PIECES         1
+#else
+# error "Unknown!"
+#endif
+
+// Represents storage for an operand. For constants, the pointer is tagged
+// with a single bit, and the untagged pointer is a pointer to a Value.
+class LAllocation : public TempObject
+{
+    uintptr_t bits_;
+
+    static const uintptr_t TAG_BIT = 1;
+    static const uintptr_t TAG_SHIFT = 0;
+    static const uintptr_t TAG_MASK = 1 << TAG_SHIFT;
+    static const uintptr_t KIND_BITS = 3;
+    static const uintptr_t KIND_SHIFT = TAG_SHIFT + TAG_BIT;
+    static const uintptr_t KIND_MASK = (1 << KIND_BITS) - 1;
+
+  protected:
+    static const uintptr_t DATA_BITS = (sizeof(uint32_t) * 8) - KIND_BITS - TAG_BIT;
+    static const uintptr_t DATA_SHIFT = KIND_SHIFT + KIND_BITS;
+    static const uintptr_t DATA_MASK = (1 << DATA_BITS) - 1;
+
+  public:
+    enum Kind {
+        USE,            // Use of a virtual register, with physical allocation policy.
+        CONSTANT_VALUE, // Constant js::Value.
+        CONSTANT_INDEX, // Constant arbitrary index.
+        GPR,            // General purpose register.
+        FPU,            // Floating-point register.
+        STACK_SLOT,     // Stack slot.
+        ARGUMENT_SLOT   // Argument slot.
+    };
+
+  protected:
+    bool isTagged() const {
+        return !!(bits_ & TAG_MASK);
+    }
+
+    int32_t data() const {
+        return int32_t(bits_) >> DATA_SHIFT;
+    }
+    void setData(int32_t data) {
+        JS_ASSERT(int32_t(data) <= int32_t(DATA_MASK));
+        bits_ &= ~(DATA_MASK << DATA_SHIFT);
+        bits_ |= (data << DATA_SHIFT);
+    }
+    void setKindAndData(Kind kind, uint32_t data) {
+        JS_ASSERT(int32_t(data) <= int32_t(DATA_MASK));
+        bits_ = (uint32_t(kind) << KIND_SHIFT) | data << DATA_SHIFT;
+    }
+
+    LAllocation(Kind kind, uint32_t data) {
+        setKindAndData(kind, data);
+    }
+    explicit LAllocation(Kind kind) {
+        setKindAndData(kind, 0);
+    }
+
+  public:
+    LAllocation() : bits_(0)
+    { }
+
+    static LAllocation *New(TempAllocator &alloc) {
+        return new(alloc) LAllocation();
+    }
+    template <typename T>
+    static LAllocation *New(TempAllocator &alloc, const T &other) {
+        return new(alloc) LAllocation(other);
+    }
+
+    // The value pointer must be rooted in MIR and have its low bit cleared.
+    explicit LAllocation(const Value *vp) {
+        bits_ = uintptr_t(vp);
+        JS_ASSERT(!isTagged());
+        bits_ |= TAG_MASK;
+    }
+    inline explicit LAllocation(const AnyRegister &reg);
+
+    Kind kind() const {
+        if (isTagged())
+            return CONSTANT_VALUE;
+        return (Kind)((bits_ >> KIND_SHIFT) & KIND_MASK);
+    }
+
+    bool isUse() const {
+        return kind() == USE;
+    }
+    bool isConstant() const {
+        return isConstantValue() || isConstantIndex();
+    }
+    bool isConstantValue() const {
+        return kind() == CONSTANT_VALUE;
+    }
+    bool isConstantIndex() const {
+        return kind() == CONSTANT_INDEX;
+    }
+    bool isValue() const {
+        return kind() == CONSTANT_VALUE;
+    }
+    bool isGeneralReg() const {
+        return kind() == GPR;
+    }
+    bool isFloatReg() const {
+        return kind() == FPU;
+    }
+    bool isStackSlot() const {
+        return kind() == STACK_SLOT;
+    }
+    bool isArgument() const {
+        return kind() == ARGUMENT_SLOT;
+    }
+    bool isRegister() const {
+        return isGeneralReg() || isFloatReg();
+    }
+    bool isRegister(bool needFloat) const {
+        return needFloat ? isFloatReg() : isGeneralReg();
+    }
+    bool isMemory() const {
+        return isStackSlot() || isArgument();
+    }
+    inline LUse *toUse();
+    inline const LUse *toUse() const;
+    inline const LGeneralReg *toGeneralReg() const;
+    inline const LFloatReg *toFloatReg() const;
+    inline const LStackSlot *toStackSlot() const;
+    inline const LArgument *toArgument() const;
+    inline const LConstantIndex *toConstantIndex() const;
+    inline AnyRegister toRegister() const;
+
+    const Value *toConstant() const {
+        JS_ASSERT(isConstantValue());
+        return reinterpret_cast<const Value *>(bits_ & ~TAG_MASK);
+    }
+
+    bool operator ==(const LAllocation &other) const {
+        return bits_ == other.bits_;
+    }
+
+    bool operator !=(const LAllocation &other) const {
+        return bits_ != other.bits_;
+    }
+
+    HashNumber hash() const {
+        return bits_;
+    }
+
+#ifdef DEBUG
+    const char *toString() const;
+#else
+    const char *toString() const { return "???"; }
+#endif
+
+    void dump() const;
+};
+
+class LUse : public LAllocation
+{
+    static const uint32_t POLICY_BITS = 3;
+    static const uint32_t POLICY_SHIFT = 0;
+    static const uint32_t POLICY_MASK = (1 << POLICY_BITS) - 1;
+    static const uint32_t REG_BITS = 5;
+    static const uint32_t REG_SHIFT = POLICY_SHIFT + POLICY_BITS;
+    static const uint32_t REG_MASK = (1 << REG_BITS) - 1;
+
+    // Whether the physical register for this operand may be reused for a def.
+    static const uint32_t USED_AT_START_BITS = 1;
+    static const uint32_t USED_AT_START_SHIFT = REG_SHIFT + REG_BITS;
+    static const uint32_t USED_AT_START_MASK = (1 << USED_AT_START_BITS) - 1;
+
+  public:
+    // Virtual registers get the remaining 20 bits.
+    static const uint32_t VREG_BITS = DATA_BITS - (USED_AT_START_SHIFT + USED_AT_START_BITS);
+    static const uint32_t VREG_SHIFT = USED_AT_START_SHIFT + USED_AT_START_BITS;
+    static const uint32_t VREG_MASK = (1 << VREG_BITS) - 1;
+
+    enum Policy {
+        // Input should be in a read-only register or stack slot.
+        ANY,
+
+        // Input must be in a read-only register.
+        REGISTER,
+
+        // Input must be in a specific, read-only register.
+        FIXED,
+
+        // Keep the used virtual register alive, and use whatever allocation is
+        // available. This is similar to ANY but hints to the register allocator
+        // that it is never useful to optimize this site.
+        KEEPALIVE,
+
+        // For snapshot inputs, indicates that the associated instruction will
+        // write this input to its output register before bailing out.
+        // The register allocator may thus allocate that output register, and
+        // does not need to keep the virtual register alive (alternatively,
+        // this may be treated as KEEPALIVE).
+        RECOVERED_INPUT
+    };
+
+    void set(Policy policy, uint32_t reg, bool usedAtStart) {
+        setKindAndData(USE, (policy << POLICY_SHIFT) |
+                            (reg << REG_SHIFT) |
+                            ((usedAtStart ? 1 : 0) << USED_AT_START_SHIFT));
+    }
+
+  public:
+    LUse(uint32_t vreg, Policy policy, bool usedAtStart = false) {
+        set(policy, 0, usedAtStart);
+        setVirtualRegister(vreg);
+    }
+    LUse(Policy policy, bool usedAtStart = false) {
+        set(policy, 0, usedAtStart);
+    }
+    LUse(Register reg, bool usedAtStart = false) {
+        set(FIXED, reg.code(), usedAtStart);
+    }
+    LUse(FloatRegister reg, bool usedAtStart = false) {
+        set(FIXED, reg.code(), usedAtStart);
+    }
+    LUse(Register reg, uint32_t virtualRegister) {
+        set(FIXED, reg.code(), false);
+        setVirtualRegister(virtualRegister);
+    }
+    LUse(FloatRegister reg, uint32_t virtualRegister) {
+        set(FIXED, reg.code(), false);
+        setVirtualRegister(virtualRegister);
+    }
+
+    void setVirtualRegister(uint32_t index) {
+        JS_ASSERT(index < VREG_MASK);
+
+        uint32_t old = data() & ~(VREG_MASK << VREG_SHIFT);
+        setData(old | (index << VREG_SHIFT));
+    }
+
+    Policy policy() const {
+        Policy policy = (Policy)((data() >> POLICY_SHIFT) & POLICY_MASK);
+        return policy;
+    }
+    uint32_t virtualRegister() const {
+        uint32_t index = (data() >> VREG_SHIFT) & VREG_MASK;
+        return index;
+    }
+    uint32_t registerCode() const {
+        JS_ASSERT(policy() == FIXED);
+        return (data() >> REG_SHIFT) & REG_MASK;
+    }
+    bool isFixedRegister() const {
+        return policy() == FIXED;
+    }
+    bool usedAtStart() const {
+        return !!((data() >> USED_AT_START_SHIFT) & USED_AT_START_MASK);
+    }
+};
+
+static const uint32_t MAX_VIRTUAL_REGISTERS = LUse::VREG_MASK;
+
+class LGeneralReg : public LAllocation
+{
+  public:
+    explicit LGeneralReg(Register reg)
+      : LAllocation(GPR, reg.code())
+    { }
+
+    Register reg() const {
+        return Register::FromCode(data());
+    }
+};
+
+class LFloatReg : public LAllocation
+{
+  public:
+    explicit LFloatReg(FloatRegister reg)
+      : LAllocation(FPU, reg.code())
+    { }
+
+    FloatRegister reg() const {
+        return FloatRegister::FromCode(data());
+    }
+};
+
+// Arbitrary constant index.
+class LConstantIndex : public LAllocation
+{
+    explicit LConstantIndex(uint32_t index)
+      : LAllocation(CONSTANT_INDEX, index)
+    { }
+
+  public:
+    // Used as a placeholder for inputs that can be ignored.
+    static LConstantIndex Bogus() {
+        return LConstantIndex(0);
+    }
+
+    static LConstantIndex FromIndex(uint32_t index) {
+        return LConstantIndex(index);
+    }
+
+    uint32_t index() const {
+        return data();
+    }
+};
+
+// Stack slots are indices into the stack. The indices are byte indices.
+class LStackSlot : public LAllocation
+{
+  public:
+    explicit LStackSlot(uint32_t slot)
+      : LAllocation(STACK_SLOT, slot)
+    { }
+
+    uint32_t slot() const {
+        return data();
+    }
+};
+
+// Arguments are reverse indices into the stack. The indices are byte indices.
+class LArgument : public LAllocation
+{
+  public:
+    explicit LArgument(int32_t index)
+      : LAllocation(ARGUMENT_SLOT, index)
+    { }
+
+    int32_t index() const {
+        return data();
+    }
+};
+
+// Represents storage for a definition.
+class LDefinition
+{
+    // Bits containing policy, type, and virtual register.
+    uint32_t bits_;
+
+    // Before register allocation, this optionally contains a fixed policy.
+    // Register allocation assigns this field to a physical policy if none is
+    // preset.
+    //
+    // Right now, pre-allocated outputs are limited to the following:
+    //   * Physical argument stack slots.
+    //   * Physical registers.
+    LAllocation output_;
+
+    static const uint32_t TYPE_BITS = 3;
+    static const uint32_t TYPE_SHIFT = 0;
+    static const uint32_t TYPE_MASK = (1 << TYPE_BITS) - 1;
+    static const uint32_t POLICY_BITS = 2;
+    static const uint32_t POLICY_SHIFT = TYPE_SHIFT + TYPE_BITS;
+    static const uint32_t POLICY_MASK = (1 << POLICY_BITS) - 1;
+
+    static const uint32_t VREG_BITS = (sizeof(uint32_t) * 8) - (POLICY_BITS + TYPE_BITS);
+    static const uint32_t VREG_SHIFT = POLICY_SHIFT + POLICY_BITS;
+    static const uint32_t VREG_MASK = (1 << VREG_BITS) - 1;
+
+  public:
+    // Note that definitions, by default, are always allocated a register,
+    // unless the policy specifies that an input can be re-used and that input
+    // is a stack slot.
+    enum Policy {
+        // A random register of an appropriate class will be assigned.
+        DEFAULT,
+
+        // The policy is predetermined by the LAllocation attached to this
+        // definition. The allocation may be:
+        //   * A register, which may not appear as any fixed temporary.
+        //   * A stack slot or argument.
+        //
+        // Register allocation will not modify a preset allocation.
+        PRESET,
+
+        // One definition per instruction must re-use the first input
+        // allocation, which (for now) must be a register.
+        MUST_REUSE_INPUT,
+
+        // This definition's virtual register is the same as another; this is
+        // for instructions which consume a register and silently define it as
+        // the same register. It is not legal to use this if doing so would
+        // change the type of the virtual register.
+        PASSTHROUGH
+    };
+
+    enum Type {
+        GENERAL,    // Generic, integer or pointer-width data (GPR).
+        INT32,      // int32 data (GPR).
+        OBJECT,     // Pointer that may be collected as garbage (GPR).
+        SLOTS,      // Slots/elements pointer that may be moved by minor GCs (GPR).
+        FLOAT32,    // 32-bit floating-point value (FPU).
+        DOUBLE,     // 64-bit floating-point value (FPU).
+#ifdef JS_NUNBOX32
+        // A type virtual register must be followed by a payload virtual
+        // register, as both will be tracked as a single gcthing.
+        TYPE,
+        PAYLOAD
+#else
+        BOX         // Joined box, for punbox systems. (GPR, gcthing)
+#endif
+    };
+
+    void set(uint32_t index, Type type, Policy policy) {
+        JS_STATIC_ASSERT(MAX_VIRTUAL_REGISTERS <= VREG_MASK);
+        bits_ = (index << VREG_SHIFT) | (policy << POLICY_SHIFT) | (type << TYPE_SHIFT);
+    }
+
+  public:
+    LDefinition(uint32_t index, Type type, Policy policy = DEFAULT) {
+        set(index, type, policy);
+    }
+
+    LDefinition(Type type, Policy policy = DEFAULT) {
+        set(0, type, policy);
+    }
+
+    LDefinition(Type type, const LAllocation &a)
+      : output_(a)
+    {
+        set(0, type, PRESET);
+    }
+
+    LDefinition(uint32_t index, Type type, const LAllocation &a)
+      : output_(a)
+    {
+        set(index, type, PRESET);
+    }
+
+    LDefinition() : bits_(0)
+    { }
+
+    static LDefinition BogusTemp() {
+        return LDefinition(GENERAL, LConstantIndex::Bogus());
+    }
+
+    Policy policy() const {
+        return (Policy)((bits_ >> POLICY_SHIFT) & POLICY_MASK);
+    }
+    Type type() const {
+        return (Type)((bits_ >> TYPE_SHIFT) & TYPE_MASK);
+    }
+    bool isFloatReg() const {
+        return type() == FLOAT32 || type() == DOUBLE;
+    }
+    uint32_t virtualRegister() const {
+        return (bits_ >> VREG_SHIFT) & VREG_MASK;
+    }
+    LAllocation *output() {
+        return &output_;
+    }
+    const LAllocation *output() const {
+        return &output_;
+    }
+    bool isPreset() const {
+        return policy() == PRESET;
+    }
+    bool isBogusTemp() const {
+        return isPreset() && output()->isConstantIndex();
+    }
+    void setVirtualRegister(uint32_t index) {
+        JS_ASSERT(index < VREG_MASK);
+        bits_ &= ~(VREG_MASK << VREG_SHIFT);
+        bits_ |= index << VREG_SHIFT;
+    }
+    void setOutput(const LAllocation &a) {
+        output_ = a;
+        if (!a.isUse()) {
+            bits_ &= ~(POLICY_MASK << POLICY_SHIFT);
+            bits_ |= PRESET << POLICY_SHIFT;
+        }
+    }
+    void setReusedInput(uint32_t operand) {
+        output_ = LConstantIndex::FromIndex(operand);
+    }
+    uint32_t getReusedInput() const {
+        JS_ASSERT(policy() == LDefinition::MUST_REUSE_INPUT);
+        return output_.toConstantIndex()->index();
+    }
+
+    static inline Type TypeFrom(MIRType type) {
+        switch (type) {
+          case MIRType_Boolean:
+          case MIRType_Int32:
+            // The stack slot allocator doesn't currently support allocating
+            // 1-byte slots, so for now we lower MIRType_Boolean into INT32.
+            static_assert(sizeof(bool) <= sizeof(int32_t), "bool doesn't fit in an int32 slot");
+            return LDefinition::INT32;
+          case MIRType_String:
+          case MIRType_Object:
+            return LDefinition::OBJECT;
+          case MIRType_Double:
+            return LDefinition::DOUBLE;
+          case MIRType_Float32:
+            return LDefinition::FLOAT32;
+#if defined(JS_PUNBOX64)
+          case MIRType_Value:
+            return LDefinition::BOX;
+#endif
+          case MIRType_Slots:
+          case MIRType_Elements:
+            return LDefinition::SLOTS;
+          case MIRType_Pointer:
+            return LDefinition::GENERAL;
+          case MIRType_ForkJoinContext:
+            return LDefinition::GENERAL;
+          default:
+            MOZ_ASSUME_UNREACHABLE("unexpected type");
+        }
+    }
+};
+
+// Forward declarations of LIR types.
+#define LIROP(op) class L##op;
+    LIR_OPCODE_LIST(LIROP)
+#undef LIROP
+
+class LSnapshot;
+class LSafepoint;
+class LInstructionVisitor;
+
+class LInstruction
+  : public TempObject,
+    public InlineListNode<LInstruction>
+{
+    uint32_t id_;
+
+    // This snapshot could be set after a ResumePoint.  It is used to restart
+    // from the resume point pc.
+    LSnapshot *snapshot_;
+
+    // Structure capturing the set of stack slots and registers which are known
+    // to hold either gcthings or Values.
+    LSafepoint *safepoint_;
+
+  protected:
+    MDefinition *mir_;
+
+    LInstruction()
+      : id_(0),
+        snapshot_(nullptr),
+        safepoint_(nullptr),
+        mir_(nullptr)
+    { }
+
+  public:
+    class InputIterator;
+    enum Opcode {
+#   define LIROP(name) LOp_##name,
+        LIR_OPCODE_LIST(LIROP)
+#   undef LIROP
+        LOp_Invalid
+    };
+
+    const char *opName() {
+        switch (op()) {
+#   define LIR_NAME_INS(name)                   \
+            case LOp_##name: return #name;
+            LIR_OPCODE_LIST(LIR_NAME_INS)
+#   undef LIR_NAME_INS
+          default:
+            return "Invalid";
+        }
+    }
+
+    // Hook for opcodes to add extra high level detail about what code will be
+    // emitted for the op.
+    virtual const char *extraName() const {
+        return nullptr;
+    }
+
+  public:
+    virtual Opcode op() const = 0;
+
+    // Returns the number of outputs of this instruction. If an output is
+    // unallocated, it is an LDefinition, defining a virtual register.
+    virtual size_t numDefs() const = 0;
+    virtual LDefinition *getDef(size_t index) = 0;
+    virtual void setDef(size_t index, const LDefinition &def) = 0;
+
+    // Returns information about operands.
+    virtual size_t numOperands() const = 0;
+    virtual LAllocation *getOperand(size_t index) = 0;
+    virtual void setOperand(size_t index, const LAllocation &a) = 0;
+
+    // Returns information about temporary registers needed. Each temporary
+    // register is an LUse with a TEMPORARY policy, or a fixed register.
+    virtual size_t numTemps() const = 0;
+    virtual LDefinition *getTemp(size_t index) = 0;
+    virtual void setTemp(size_t index, const LDefinition &a) = 0;
+
+    // Returns the number of successors of this instruction, if it is a control
+    // transfer instruction, or zero otherwise.
+    virtual size_t numSuccessors() const = 0;
+    virtual MBasicBlock *getSuccessor(size_t i) const = 0;
+    virtual void setSuccessor(size_t i, MBasicBlock *successor) = 0;
+
+    virtual bool isCall() const {
+        return false;
+    }
+    uint32_t id() const {
+        return id_;
+    }
+    void setId(uint32_t id) {
+        JS_ASSERT(!id_);
+        JS_ASSERT(id);
+        id_ = id;
+    }
+    LSnapshot *snapshot() const {
+        return snapshot_;
+    }
+    LSafepoint *safepoint() const {
+        return safepoint_;
+    }
+    void setMir(MDefinition *mir) {
+        mir_ = mir;
+    }
+    MDefinition *mirRaw() const {
+        /* Untyped MIR for this op. Prefer mir() methods in subclasses. */
+        return mir_;
+    }
+    void assignSnapshot(LSnapshot *snapshot);
+    void initSafepoint(TempAllocator &alloc);
+
+    // For an instruction which has a MUST_REUSE_INPUT output, whether that
+    // output register will be restored to its original value when bailing out.
+    virtual bool recoversInput() const {
+        return false;
+    }
+
+    virtual void dump(FILE *fp);
+    void dump();
+    static void printName(FILE *fp, Opcode op);
+    virtual void printName(FILE *fp);
+    virtual void printOperands(FILE *fp);
+    virtual void printInfo(FILE *fp) { }
+
+  public:
+    // Opcode testing and casts.
+#   define LIROP(name)                                                      \
+    bool is##name() const {                                                 \
+        return op() == LOp_##name;                                          \
+    }                                                                       \
+    inline L##name *to##name();
+    LIR_OPCODE_LIST(LIROP)
+#   undef LIROP
+
+    virtual bool accept(LInstructionVisitor *visitor) = 0;
+};
+
+class LInstructionVisitor
+{
+    LInstruction *ins_;
+
+  protected:
+    jsbytecode *lastPC_;
+
+    LInstruction *instruction() {
+        return ins_;
+    }
+
+  public:
+    void setInstruction(LInstruction *ins) {
+        ins_ = ins;
+        if (ins->mirRaw())
+            lastPC_ = ins->mirRaw()->trackedPc();
+    }
+
+    LInstructionVisitor()
+      : ins_(nullptr),
+        lastPC_(nullptr)
+    {}
+
+  public:
+#define VISIT_INS(op) virtual bool visit##op(L##op *) { MOZ_ASSUME_UNREACHABLE("NYI: " #op); }
+    LIR_OPCODE_LIST(VISIT_INS)
+#undef VISIT_INS
+};
+
+typedef InlineList<LInstruction>::iterator LInstructionIterator;
+typedef InlineList<LInstruction>::reverse_iterator LInstructionReverseIterator;
+
+class LPhi;
+class LMoveGroup;
+class LBlock : public TempObject
+{
+    MBasicBlock *block_;
+    Vector<LPhi *, 4, IonAllocPolicy> phis_;
+    InlineList<LInstruction> instructions_;
+    LMoveGroup *entryMoveGroup_;
+    LMoveGroup *exitMoveGroup_;
+    Label label_;
+
+    LBlock(TempAllocator &alloc, MBasicBlock *block)
+      : block_(block),
+        phis_(alloc),
+        entryMoveGroup_(nullptr),
+        exitMoveGroup_(nullptr)
+    { }
+
+  public:
+    static LBlock *New(TempAllocator &alloc, MBasicBlock *from) {
+        return new(alloc) LBlock(alloc, from);
+    }
+    void add(LInstruction *ins) {
+        instructions_.pushBack(ins);
+    }
+    bool addPhi(LPhi *phi) {
+        return phis_.append(phi);
+    }
+    size_t numPhis() const {
+        return phis_.length();
+    }
+    LPhi *getPhi(size_t index) const {
+        return phis_[index];
+    }
+    void removePhi(size_t index) {
+        phis_.erase(&phis_[index]);
+    }
+    void clearPhis() {
+        phis_.clear();
+    }
+    MBasicBlock *mir() const {
+        return block_;
+    }
+    LInstructionIterator begin() {
+        return instructions_.begin();
+    }
+    LInstructionIterator begin(LInstruction *at) {
+        return instructions_.begin(at);
+    }
+    LInstructionIterator end() {
+        return instructions_.end();
+    }
+    LInstructionReverseIterator rbegin() {
+        return instructions_.rbegin();
+    }
+    LInstructionReverseIterator rbegin(LInstruction *at) {
+        return instructions_.rbegin(at);
+    }
+    LInstructionReverseIterator rend() {
+        return instructions_.rend();
+    }
+    InlineList<LInstruction> &instructions() {
+        return instructions_;
+    }
+    void insertAfter(LInstruction *at, LInstruction *ins) {
+        instructions_.insertAfter(at, ins);
+    }
+    void insertBefore(LInstruction *at, LInstruction *ins) {
+        JS_ASSERT(!at->isLabel());
+        instructions_.insertBefore(at, ins);
+    }
+    uint32_t firstId();
+    uint32_t lastId();
+    Label *label() {
+        return &label_;
+    }
+    LMoveGroup *getEntryMoveGroup(TempAllocator &alloc);
+    LMoveGroup *getExitMoveGroup(TempAllocator &alloc);
+};
+
+template <size_t Defs, size_t Operands, size_t Temps>
+class LInstructionHelper : public LInstruction
+{
+    mozilla::Array<LDefinition, Defs> defs_;
+    mozilla::Array<LAllocation, Operands> operands_;
+    mozilla::Array<LDefinition, Temps> temps_;
+
+  public:
+    size_t numDefs() const MOZ_FINAL MOZ_OVERRIDE {
+        return Defs;
+    }
+    LDefinition *getDef(size_t index) MOZ_FINAL MOZ_OVERRIDE {
+        return &defs_[index];
+    }
+    size_t numOperands() const MOZ_FINAL MOZ_OVERRIDE {
+        return Operands;
+    }
+    LAllocation *getOperand(size_t index) MOZ_FINAL MOZ_OVERRIDE {
+        return &operands_[index];
+    }
+    size_t numTemps() const MOZ_FINAL MOZ_OVERRIDE {
+        return Temps;
+    }
+    LDefinition *getTemp(size_t index) MOZ_FINAL MOZ_OVERRIDE {
+        return &temps_[index];
+    }
+
+    void setDef(size_t index, const LDefinition &def) MOZ_FINAL MOZ_OVERRIDE {
+        defs_[index] = def;
+    }
+    void setOperand(size_t index, const LAllocation &a) MOZ_FINAL MOZ_OVERRIDE {
+        operands_[index] = a;
+    }
+    void setTemp(size_t index, const LDefinition &a) MOZ_FINAL MOZ_OVERRIDE {
+        temps_[index] = a;
+    }
+
+    size_t numSuccessors() const {
+        return 0;
+    }
+    MBasicBlock *getSuccessor(size_t i) const {
+        JS_ASSERT(false);
+        return nullptr;
+    }
+    void setSuccessor(size_t i, MBasicBlock *successor) {
+        JS_ASSERT(false);
+    }
+
+    // Default accessors, assuming a single input and output, respectively.
+    const LAllocation *input() {
+        JS_ASSERT(numOperands() == 1);
+        return getOperand(0);
+    }
+    const LDefinition *output() {
+        JS_ASSERT(numDefs() == 1);
+        return getDef(0);
+    }
+
+    virtual void printInfo(FILE *fp) {
+        printOperands(fp);
+    }
+};
+
+template <size_t Defs, size_t Operands, size_t Temps>
+class LCallInstructionHelper : public LInstructionHelper<Defs, Operands, Temps>
+{
+  public:
+    virtual bool isCall() const {
+        return true;
+    }
+};
+
+class LRecoverInfo : public TempObject
+{
+  public:
+    typedef Vector<MResumePoint *, 2, IonAllocPolicy> Instructions;
+
+  private:
+    // List of instructions needed to recover the stack frames.
+    // Outer frames are stored before inner frames.
+    Instructions instructions_;
+
+    // Cached offset where this resume point is encoded.
+    RecoverOffset recoverOffset_;
+
+    LRecoverInfo(TempAllocator &alloc);
+    bool init(MResumePoint *mir);
+
+  public:
+    static LRecoverInfo *New(MIRGenerator *gen, MResumePoint *mir);
+
+    // Resume point of the inner most function.
+    MResumePoint *mir() const {
+        return instructions_.back();
+    }
+    RecoverOffset recoverOffset() const {
+        return recoverOffset_;
+    }
+    void setRecoverOffset(RecoverOffset offset) {
+        JS_ASSERT(recoverOffset_ == INVALID_RECOVER_OFFSET);
+        recoverOffset_ = offset;
+    }
+
+    MResumePoint **begin() {
+        return instructions_.begin();
+    }
+    MResumePoint **end() {
+        return instructions_.end();
+    }
+};
+
+// An LSnapshot is the reflection of an MResumePoint in LIR. Unlike MResumePoints,
+// they cannot be shared, as they are filled in by the register allocator in
+// order to capture the precise low-level stack state in between an
+// instruction's input and output. During code generation, LSnapshots are
+// compressed and saved in the compiled script.
+class LSnapshot : public TempObject
+{
+  private:
+    uint32_t numSlots_;
+    LAllocation *slots_;
+    LRecoverInfo *recoverInfo_;
+    SnapshotOffset snapshotOffset_;
+    BailoutId bailoutId_;
+    BailoutKind bailoutKind_;
+
+    LSnapshot(LRecoverInfo *recover, BailoutKind kind);
+    bool init(MIRGenerator *gen);
+
+  public:
+    static LSnapshot *New(MIRGenerator *gen, LRecoverInfo *recover, BailoutKind kind);
+
+    size_t numEntries() const {
+        return numSlots_;
+    }
+    size_t numSlots() const {
+        return numSlots_ / BOX_PIECES;
+    }
+    LAllocation *payloadOfSlot(size_t i) {
+        JS_ASSERT(i < numSlots());
+        size_t entryIndex = (i * BOX_PIECES) + (BOX_PIECES - 1);
+        return getEntry(entryIndex);
+    }
+#ifdef JS_NUNBOX32
+    LAllocation *typeOfSlot(size_t i) {
+        JS_ASSERT(i < numSlots());
+        size_t entryIndex = (i * BOX_PIECES) + (BOX_PIECES - 2);
+        return getEntry(entryIndex);
+    }
+#endif
+    LAllocation *getEntry(size_t i) {
+        JS_ASSERT(i < numSlots_);
+        return &slots_[i];
+    }
+    void setEntry(size_t i, const LAllocation &alloc) {
+        JS_ASSERT(i < numSlots_);
+        slots_[i] = alloc;
+    }
+    LRecoverInfo *recoverInfo() const {
+        return recoverInfo_;
+    }
+    MResumePoint *mir() const {
+        return recoverInfo()->mir();
+    }
+    SnapshotOffset snapshotOffset() const {
+        return snapshotOffset_;
+    }
+    BailoutId bailoutId() const {
+        return bailoutId_;
+    }
+    void setSnapshotOffset(SnapshotOffset offset) {
+        JS_ASSERT(snapshotOffset_ == INVALID_SNAPSHOT_OFFSET);
+        snapshotOffset_ = offset;
+    }
+    void setBailoutId(BailoutId id) {
+        JS_ASSERT(bailoutId_ == INVALID_BAILOUT_ID);
+        bailoutId_ = id;
+    }
+    BailoutKind bailoutKind() const {
+        return bailoutKind_;
+    }
+    void setBailoutKind(BailoutKind kind) {
+        bailoutKind_ = kind;
+    }
+    void rewriteRecoveredInput(LUse input);
+};
+
+struct SafepointNunboxEntry {
+    LAllocation type;
+    LAllocation payload;
+
+    SafepointNunboxEntry() { }
+    SafepointNunboxEntry(LAllocation type, LAllocation payload)
+      : type(type), payload(payload)
+    { }
+};
+
+class LSafepoint : public TempObject
+{
+    typedef SafepointNunboxEntry NunboxEntry;
+
+  public:
+    typedef Vector<uint32_t, 0, IonAllocPolicy> SlotList;
+    typedef Vector<NunboxEntry, 0, IonAllocPolicy> NunboxList;
+
+  private:
+    // The information in a safepoint describes the registers and gc related
+    // values that are live at the start of the associated instruction.
+
+    // The set of registers which are live at an OOL call made within the
+    // instruction. This includes any registers for inputs which are not
+    // use-at-start, any registers for temps, and any registers live after the
+    // call except outputs of the instruction.
+    //
+    // For call instructions, the live regs are empty. Call instructions may
+    // have register inputs or temporaries, which will *not* be in the live
+    // registers: if passed to the call, the values passed will be marked via
+    // MarkJitExitFrame, and no registers can be live after the instruction
+    // except its outputs.
+    RegisterSet liveRegs_;
+
+    // The subset of liveRegs which contains gcthing pointers.
+    GeneralRegisterSet gcRegs_;
+
+#ifdef CHECK_OSIPOINT_REGISTERS
+    // Clobbered regs of the current instruction. This set is never written to
+    // the safepoint; it's only used by assertions during compilation.
+    RegisterSet clobberedRegs_;
+#endif
+
+    // Offset to a position in the safepoint stream, or
+    // INVALID_SAFEPOINT_OFFSET.
+    uint32_t safepointOffset_;
+
+    // Assembler buffer displacement to OSI point's call location.
+    uint32_t osiCallPointOffset_;
+
+    // List of stack slots which have gcthing pointers.
+    SlotList gcSlots_;
+
+    // List of stack slots which have Values.
+    SlotList valueSlots_;
+
+#ifdef JS_NUNBOX32
+    // List of registers (in liveRegs) and stack slots which contain pieces of Values.
+    NunboxList nunboxParts_;
+
+    // Number of nunboxParts which are not completely filled in.
+    uint32_t partialNunboxes_;
+#elif JS_PUNBOX64
+    // The subset of liveRegs which have Values.
+    GeneralRegisterSet valueRegs_;
+#endif
+
+    // The subset of liveRegs which contains pointers to slots/elements.
+    GeneralRegisterSet slotsOrElementsRegs_;
+
+    // List of stack slots which have slots/elements pointers.
+    SlotList slotsOrElementsSlots_;
+
+  public:
+    void assertInvariants() {
+        // Every register in valueRegs and gcRegs should also be in liveRegs.
+#ifndef JS_NUNBOX32
+        JS_ASSERT((valueRegs().bits() & ~liveRegs().gprs().bits()) == 0);
+#endif
+        JS_ASSERT((gcRegs().bits() & ~liveRegs().gprs().bits()) == 0);
+    }
+
+    LSafepoint(TempAllocator &alloc)
+      : safepointOffset_(INVALID_SAFEPOINT_OFFSET)
+      , osiCallPointOffset_(0)
+      , gcSlots_(alloc)
+      , valueSlots_(alloc)
+#ifdef JS_NUNBOX32
+      , nunboxParts_(alloc)
+      , partialNunboxes_(0)
+#endif
+      , slotsOrElementsSlots_(alloc)
+    {
+      assertInvariants();
+    }
+    void addLiveRegister(AnyRegister reg) {
+        liveRegs_.addUnchecked(reg);
+        assertInvariants();
+    }
+    const RegisterSet &liveRegs() const {
+        return liveRegs_;
+    }
+#ifdef CHECK_OSIPOINT_REGISTERS
+    void addClobberedRegister(AnyRegister reg) {
+        clobberedRegs_.addUnchecked(reg);
+        assertInvariants();
+    }
+    const RegisterSet &clobberedRegs() const {
+        return clobberedRegs_;
+    }
+#endif
+    void addGcRegister(Register reg) {
+        gcRegs_.addUnchecked(reg);
+        assertInvariants();
+    }
+    GeneralRegisterSet gcRegs() const {
+        return gcRegs_;
+    }
+    bool addGcSlot(uint32_t slot) {
+        bool result = gcSlots_.append(slot);
+        if (result)
+            assertInvariants();
+        return result;
+    }
+    SlotList &gcSlots() {
+        return gcSlots_;
+    }
+
+    SlotList &slotsOrElementsSlots() {
+        return slotsOrElementsSlots_;
+    }
+    GeneralRegisterSet slotsOrElementsRegs() const {
+        return slotsOrElementsRegs_;
+    }
+    void addSlotsOrElementsRegister(Register reg) {
+        slotsOrElementsRegs_.addUnchecked(reg);
+        assertInvariants();
+    }
+    bool addSlotsOrElementsSlot(uint32_t slot) {
+        bool result = slotsOrElementsSlots_.append(slot);
+        if (result)
+            assertInvariants();
+        return result;
+    }
+    bool addSlotsOrElementsPointer(LAllocation alloc) {
+        if (alloc.isStackSlot())
+            return addSlotsOrElementsSlot(alloc.toStackSlot()->slot());
+        JS_ASSERT(alloc.isRegister());
+        addSlotsOrElementsRegister(alloc.toRegister().gpr());
+        assertInvariants();
+        return true;
+    }
+    bool hasSlotsOrElementsPointer(LAllocation alloc) const {
+        if (alloc.isRegister())
+            return slotsOrElementsRegs().has(alloc.toRegister().gpr());
+        if (alloc.isStackSlot()) {
+            for (size_t i = 0; i < slotsOrElementsSlots_.length(); i++) {
+                if (slotsOrElementsSlots_[i] == alloc.toStackSlot()->slot())
+                    return true;
+            }
+            return false;
+        }
+        return false;
+    }
+
+    bool addGcPointer(LAllocation alloc) {
+        if (alloc.isStackSlot())
+            return addGcSlot(alloc.toStackSlot()->slot());
+        if (alloc.isRegister())
+            addGcRegister(alloc.toRegister().gpr());
+        assertInvariants();
+        return true;
+    }
+
+    bool hasGcPointer(LAllocation alloc) const {
+        if (alloc.isRegister())
+            return gcRegs().has(alloc.toRegister().gpr());
+        if (alloc.isStackSlot()) {
+            for (size_t i = 0; i < gcSlots_.length(); i++) {
+                if (gcSlots_[i] == alloc.toStackSlot()->slot())
+                    return true;
+            }
+            return false;
+        }
+        JS_ASSERT(alloc.isArgument());
+        return true;
+    }
+
+    bool addValueSlot(uint32_t slot) {
+        bool result = valueSlots_.append(slot);
+        if (result)
+            assertInvariants();
+        return result;
+    }
+    SlotList &valueSlots() {
+        return valueSlots_;
+    }
+
+    bool hasValueSlot(uint32_t slot) const {
+        for (size_t i = 0; i < valueSlots_.length(); i++) {
+            if (valueSlots_[i] == slot)
+                return true;
+        }
+        return false;
+    }
+
+#ifdef JS_NUNBOX32
+
+    bool addNunboxParts(LAllocation type, LAllocation payload) {
+        bool result = nunboxParts_.append(NunboxEntry(type, payload));
+        if (result)
+            assertInvariants();
+        return result;
+    }
+
+    bool addNunboxType(uint32_t typeVreg, LAllocation type) {
+        for (size_t i = 0; i < nunboxParts_.length(); i++) {
+            if (nunboxParts_[i].type == type)
+                return true;
+            if (nunboxParts_[i].type == LUse(typeVreg, LUse::ANY)) {
+                nunboxParts_[i].type = type;
+                partialNunboxes_--;
+                return true;
+            }
+        }
+        partialNunboxes_++;
+
+        // vregs for nunbox pairs are adjacent, with the type coming first.
+        uint32_t payloadVreg = typeVreg + 1;
+        bool result = nunboxParts_.append(NunboxEntry(type, LUse(payloadVreg, LUse::ANY)));
+        if (result)
+            assertInvariants();
+        return result;
+    }
+
+    bool hasNunboxType(LAllocation type) const {
+        if (type.isArgument())
+            return true;
+        if (type.isStackSlot() && hasValueSlot(type.toStackSlot()->slot() + 1))
+            return true;
+        for (size_t i = 0; i < nunboxParts_.length(); i++) {
+            if (nunboxParts_[i].type == type)
+                return true;
+        }
+        return false;
+    }
+
+    bool addNunboxPayload(uint32_t payloadVreg, LAllocation payload) {
+        for (size_t i = 0; i < nunboxParts_.length(); i++) {
+            if (nunboxParts_[i].payload == payload)
+                return true;
+            if (nunboxParts_[i].payload == LUse(payloadVreg, LUse::ANY)) {
+                partialNunboxes_--;
+                nunboxParts_[i].payload = payload;
+                return true;
+            }
+        }
+        partialNunboxes_++;
+
+        // vregs for nunbox pairs are adjacent, with the type coming first.
+        uint32_t typeVreg = payloadVreg - 1;
+        bool result = nunboxParts_.append(NunboxEntry(LUse(typeVreg, LUse::ANY), payload));
+        if (result)
+            assertInvariants();
+        return result;
+    }
+
+    bool hasNunboxPayload(LAllocation payload) const {
+        if (payload.isArgument())
+            return true;
+        if (payload.isStackSlot() && hasValueSlot(payload.toStackSlot()->slot()))
+            return true;
+        for (size_t i = 0; i < nunboxParts_.length(); i++) {
+            if (nunboxParts_[i].payload == payload)
+                return true;
+        }
+        return false;
+    }
+
+    NunboxList &nunboxParts() {
+        return nunboxParts_;
+    }
+
+    uint32_t partialNunboxes() {
+        return partialNunboxes_;
+    }
+
+#elif JS_PUNBOX64
+
+    void addValueRegister(Register reg) {
+        valueRegs_.add(reg);
+        assertInvariants();
+    }
+    GeneralRegisterSet valueRegs() const {
+        return valueRegs_;
+    }
+
+    bool addBoxedValue(LAllocation alloc) {
+        if (alloc.isRegister()) {
+            Register reg = alloc.toRegister().gpr();
+            if (!valueRegs().has(reg))
+                addValueRegister(reg);
+            return true;
+        }
+        if (alloc.isStackSlot()) {
+            uint32_t slot = alloc.toStackSlot()->slot();
+            for (size_t i = 0; i < valueSlots().length(); i++) {
+                if (valueSlots()[i] == slot)
+                    return true;
+            }
+            return addValueSlot(slot);
+        }
+        JS_ASSERT(alloc.isArgument());
+        return true;
+    }
+
+    bool hasBoxedValue(LAllocation alloc) const {
+        if (alloc.isRegister())
+            return valueRegs().has(alloc.toRegister().gpr());
+        if (alloc.isStackSlot())
+            return hasValueSlot(alloc.toStackSlot()->slot());
+        JS_ASSERT(alloc.isArgument());
+        return true;
+    }
+
+#endif // JS_PUNBOX64
+
+    bool encoded() const {
+        return safepointOffset_ != INVALID_SAFEPOINT_OFFSET;
+    }
+    uint32_t offset() const {
+        JS_ASSERT(encoded());
+        return safepointOffset_;
+    }
+    void setOffset(uint32_t offset) {
+        safepointOffset_ = offset;
+    }
+    uint32_t osiReturnPointOffset() const {
+        // In general, pointer arithmetic on code is bad, but in this case,
+        // getting the return address from a call instruction, stepping over pools
+        // would be wrong.
+        return osiCallPointOffset_ + Assembler::patchWrite_NearCallSize();
+    }
+    uint32_t osiCallPointOffset() const {
+        return osiCallPointOffset_;
+    }
+    void setOsiCallPointOffset(uint32_t osiCallPointOffset) {
+        JS_ASSERT(!osiCallPointOffset_);
+        osiCallPointOffset_ = osiCallPointOffset;
+    }
+    void fixupOffset(MacroAssembler *masm) {
+        osiCallPointOffset_ = masm->actualOffset(osiCallPointOffset_);
+    }
+};
+
+class LInstruction::InputIterator
+{
+  private:
+    LInstruction &ins_;
+    size_t idx_;
+    bool snapshot_;
+
+    void handleOperandsEnd() {
+        // Iterate on the snapshot when iteration over all operands is done.
+        if (!snapshot_ && idx_ == ins_.numOperands() && ins_.snapshot()) {
+            idx_ = 0;
+            snapshot_ = true;
+        }
+    }
+
+public:
+    InputIterator(LInstruction &ins) :
+      ins_(ins),
+      idx_(0),
+      snapshot_(false)
+    {
+        handleOperandsEnd();
+    }
+
+    bool more() const {
+        if (snapshot_)
+            return idx_ < ins_.snapshot()->numEntries();
+        if (idx_ < ins_.numOperands())
+            return true;
+        if (ins_.snapshot() && ins_.snapshot()->numEntries())
+            return true;
+        return false;
+    }
+
+    bool isSnapshotInput() const {
+        return snapshot_;
+    }
+
+    void next() {
+        JS_ASSERT(more());
+        idx_++;
+        handleOperandsEnd();
+    }
+
+    void replace(const LAllocation &alloc) {
+        if (snapshot_)
+            ins_.snapshot()->setEntry(idx_, alloc);
+        else
+            ins_.setOperand(idx_, alloc);
+    }
+
+    LAllocation *operator *() const {
+        if (snapshot_)
+            return ins_.snapshot()->getEntry(idx_);
+        return ins_.getOperand(idx_);
+    }
+
+    LAllocation *operator ->() const {
+        return **this;
+    }
+};
+
+class LIRGraph
+{
+    struct ValueHasher
+    {
+        typedef Value Lookup;
+        static HashNumber hash(const Value &v) {
+            return HashNumber(v.asRawBits());
+        }
+        static bool match(const Value &lhs, const Value &rhs) {
+            return lhs == rhs;
+        }
+
+#ifdef DEBUG
+        bool canOptimizeOutIfUnused();
+#endif
+    };
+
+
+    Vector<LBlock *, 16, IonAllocPolicy> blocks_;
+    Vector<Value, 0, IonAllocPolicy> constantPool_;
+    typedef HashMap<Value, uint32_t, ValueHasher, IonAllocPolicy> ConstantPoolMap;
+    ConstantPoolMap constantPoolMap_;
+    Vector<LInstruction *, 0, IonAllocPolicy> safepoints_;
+    Vector<LInstruction *, 0, IonAllocPolicy> nonCallSafepoints_;
+    uint32_t numVirtualRegisters_;
+    uint32_t numInstructions_;
+
+    // Number of stack slots needed for local spills.
+    uint32_t localSlotCount_;
+    // Number of stack slots needed for argument construction for calls.
+    uint32_t argumentSlotCount_;
+
+    // Snapshot taken before any LIR has been lowered.
+    LSnapshot *entrySnapshot_;
+
+    // LBlock containing LOsrEntry, or nullptr.
+    LBlock *osrBlock_;
+
+    MIRGraph &mir_;
+
+  public:
+    LIRGraph(MIRGraph *mir);
+
+    bool init() {
+        return constantPoolMap_.init();
+    }
+    MIRGraph &mir() const {
+        return mir_;
+    }
+    size_t numBlocks() const {
+        return blocks_.length();
+    }
+    LBlock *getBlock(size_t i) const {
+        return blocks_[i];
+    }
+    uint32_t numBlockIds() const {
+        return mir_.numBlockIds();
+    }
+    bool addBlock(LBlock *block) {
+        return blocks_.append(block);
+    }
+    uint32_t getVirtualRegister() {
+        numVirtualRegisters_ += VREG_INCREMENT;
+        return numVirtualRegisters_;
+    }
+    uint32_t numVirtualRegisters() const {
+        // Virtual registers are 1-based, not 0-based, so add one as a
+        // convenience for 0-based arrays.
+        return numVirtualRegisters_ + 1;
+    }
+    uint32_t getInstructionId() {
+        return numInstructions_++;
+    }
+    uint32_t numInstructions() const {
+        return numInstructions_;
+    }
+    void setLocalSlotCount(uint32_t localSlotCount) {
+        localSlotCount_ = localSlotCount;
+    }
+    uint32_t localSlotCount() const {
+        return localSlotCount_;
+    }
+    // Return the localSlotCount() value rounded up so that it satisfies the
+    // platform stack alignment requirement, and so that it's a multiple of
+    // the number of slots per Value.
+    uint32_t paddedLocalSlotCount() const {
+        // Round to StackAlignment, but also round to at least sizeof(Value) in
+        // case that's greater, because StackOffsetOfPassedArg rounds argument
+        // slots to 8-byte boundaries.
+        size_t Alignment = Max(sizeof(StackAlignment), sizeof(Value));
+        return AlignBytes(localSlotCount(), Alignment);
+    }
+    size_t paddedLocalSlotsSize() const {
+        return paddedLocalSlotCount();
+    }
+    void setArgumentSlotCount(uint32_t argumentSlotCount) {
+        argumentSlotCount_ = argumentSlotCount;
+    }
+    uint32_t argumentSlotCount() const {
+        return argumentSlotCount_;
+    }
+    size_t argumentsSize() const {
+        return argumentSlotCount() * sizeof(Value);
+    }
+    uint32_t totalSlotCount() const {
+        return paddedLocalSlotCount() + argumentsSize();
+    }
+    bool addConstantToPool(const Value &v, uint32_t *index);
+    size_t numConstants() const {
+        return constantPool_.length();
+    }
+    Value *constantPool() {
+        return &constantPool_[0];
+    }
+    void setEntrySnapshot(LSnapshot *snapshot) {
+        JS_ASSERT(!entrySnapshot_);
+        JS_ASSERT(snapshot->bailoutKind() == Bailout_Normal);
+        snapshot->setBailoutKind(Bailout_ArgumentCheck);
+        entrySnapshot_ = snapshot;
+    }
+    LSnapshot *entrySnapshot() const {
+        JS_ASSERT(entrySnapshot_);
+        return entrySnapshot_;
+    }
+    void setOsrBlock(LBlock *block) {
+        JS_ASSERT(!osrBlock_);
+        osrBlock_ = block;
+    }
+    LBlock *osrBlock() const {
+        return osrBlock_;
+    }
+    bool noteNeedsSafepoint(LInstruction *ins);
+    size_t numNonCallSafepoints() const {
+        return nonCallSafepoints_.length();
+    }
+    LInstruction *getNonCallSafepoint(size_t i) const {
+        return nonCallSafepoints_[i];
+    }
+    size_t numSafepoints() const {
+        return safepoints_.length();
+    }
+    LInstruction *getSafepoint(size_t i) const {
+        return safepoints_[i];
+    }
+    void removeBlock(size_t i);
+};
+
+LAllocation::LAllocation(const AnyRegister &reg)
+{
+    if (reg.isFloat())
+        *this = LFloatReg(reg.fpu());
+    else
+        *this = LGeneralReg(reg.gpr());
+}
+
+AnyRegister
+LAllocation::toRegister() const
+{
+    JS_ASSERT(isRegister());
+    if (isFloatReg())
+        return AnyRegister(toFloatReg()->reg());
+    return AnyRegister(toGeneralReg()->reg());
+}
+
+} // namespace jit
+} // namespace js
+
+#define LIR_HEADER(opcode)                                                  \
+    Opcode op() const {                                                     \
+        return LInstruction::LOp_##opcode;                                  \
+    }                                                                       \
+    bool accept(LInstructionVisitor *visitor) {                             \
+        visitor->setInstruction(this);                                      \
+        return visitor->visit##opcode(this);                                \
+    }
+
+#include "jit/LIR-Common.h"
+#if defined(JS_CODEGEN_X86) || defined(JS_CODEGEN_X64)
+# if defined(JS_CODEGEN_X86)
+#  include "jit/x86/LIR-x86.h"
+# elif defined(JS_CODEGEN_X64)
+#  include "jit/x64/LIR-x64.h"
+# endif
+# include "jit/shared/LIR-x86-shared.h"
+#elif defined(JS_CODEGEN_ARM)
+# include "jit/arm/LIR-arm.h"
+#elif defined(JS_CODEGEN_MIPS)
+# include "jit/mips/LIR-mips.h"
+#else
+# error "Unknown architecture!"
+#endif
+
+#undef LIR_HEADER
+
+namespace js {
+namespace jit {
+
+#define LIROP(name)                                                         \
+    L##name *LInstruction::to##name()                                       \
+    {                                                                       \
+        JS_ASSERT(is##name());                                              \
+        return static_cast<L##name *>(this);                                \
+    }
+    LIR_OPCODE_LIST(LIROP)
+#undef LIROP
+
+#define LALLOC_CAST(type)                                                   \
+    L##type *LAllocation::to##type() {                                      \
+        JS_ASSERT(is##type());                                              \
+        return static_cast<L##type *>(this);                                \
+    }
+#define LALLOC_CONST_CAST(type)                                             \
+    const L##type *LAllocation::to##type() const {                          \
+        JS_ASSERT(is##type());                                              \
+        return static_cast<const L##type *>(this);                          \
+    }
+
+LALLOC_CAST(Use)
+LALLOC_CONST_CAST(Use)
+LALLOC_CONST_CAST(GeneralReg)
+LALLOC_CONST_CAST(FloatReg)
+LALLOC_CONST_CAST(StackSlot)
+LALLOC_CONST_CAST(Argument)
+LALLOC_CONST_CAST(ConstantIndex)
+
+#undef LALLOC_CAST
+
+#ifdef JS_NUNBOX32
+static inline signed
+OffsetToOtherHalfOfNunbox(LDefinition::Type type)
+{
+    JS_ASSERT(type == LDefinition::TYPE || type == LDefinition::PAYLOAD);
+    signed offset = (type == LDefinition::TYPE)
+                    ? PAYLOAD_INDEX - TYPE_INDEX
+                    : TYPE_INDEX - PAYLOAD_INDEX;
+    return offset;
+}
+
+static inline void
+AssertTypesFormANunbox(LDefinition::Type type1, LDefinition::Type type2)
+{
+    JS_ASSERT((type1 == LDefinition::TYPE && type2 == LDefinition::PAYLOAD) ||
+              (type2 == LDefinition::TYPE && type1 == LDefinition::PAYLOAD));
+}
+
+static inline unsigned
+OffsetOfNunboxSlot(LDefinition::Type type)
+{
+    if (type == LDefinition::PAYLOAD)
+        return NUNBOX32_PAYLOAD_OFFSET;
+    return NUNBOX32_TYPE_OFFSET;
+}
+
+// Note that stack indexes for LStackSlot are modelled backwards, so a
+// double-sized slot starting at 2 has its next word at 1, *not* 3.
+static inline unsigned
+BaseOfNunboxSlot(LDefinition::Type type, unsigned slot)
+{
+    if (type == LDefinition::PAYLOAD)
+        return slot + NUNBOX32_PAYLOAD_OFFSET;
+    return slot + NUNBOX32_TYPE_OFFSET;
+}
+#endif
+
+} // namespace jit
+} // namespace js
+
+#endif /* jit_LIR_h */