diff -r 000000000000 -r 6474c204b198 js/src/jit/x64/LIR-x64.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit/x64/LIR-x64.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,127 @@
+/* -*- 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_x64_LIR_x64_h
+#define jit_x64_LIR_x64_h
+
+namespace js {
+namespace jit {
+
+// Given a typed input, returns an untyped box.
+class LBox : public LInstructionHelper<1, 1, 0>
+{
+    MIRType type_;
+
+  public:
+    LIR_HEADER(Box)
+
+    LBox(MIRType type, const LAllocation &payload)
+      : type_(type)
+    {
+        setOperand(0, payload);
+    }
+
+    MIRType type() const {
+        return type_;
+    }
+    const char *extraName() const {
+        return StringFromMIRType(type_);
+    }
+};
+
+// Given an untyped input, guards on whether it's a specific type and returns
+// the unboxed payload.
+class LUnboxBase : public LInstructionHelper<1, 1, 0>
+{
+  public:
+    LUnboxBase(const LAllocation &input) {
+        setOperand(0, input);
+    }
+
+    static const size_t Input = 0;
+
+    MUnbox *mir() const {
+        return mir_->toUnbox();
+    }
+};
+
+class LUnbox : public LUnboxBase {
+  public:
+    LIR_HEADER(Unbox)
+
+    LUnbox(const LAllocation &input)
+      : LUnboxBase(input)
+    { }
+
+    const char *extraName() const {
+        return StringFromMIRType(mir()->type());
+    }
+};
+
+class LUnboxFloatingPoint : public LUnboxBase {
+    MIRType type_;
+
+  public:
+    LIR_HEADER(UnboxFloatingPoint)
+
+    LUnboxFloatingPoint(const LAllocation &input, MIRType type)
+      : LUnboxBase(input),
+        type_(type)
+    { }
+
+    MIRType type() const {
+        return type_;
+    }
+    const char *extraName() const {
+        return StringFromMIRType(type_);
+    }
+};
+
+// Convert a 32-bit unsigned integer to a double.
+class LAsmJSUInt32ToDouble : public LInstructionHelper<1, 1, 0>
+{
+  public:
+    LIR_HEADER(AsmJSUInt32ToDouble)
+
+    LAsmJSUInt32ToDouble(const LAllocation &input) {
+        setOperand(0, input);
+    }
+};
+
+// Convert a 32-bit unsigned integer to a float32.
+class LAsmJSUInt32ToFloat32 : public LInstructionHelper<1, 1, 0>
+{
+  public:
+    LIR_HEADER(AsmJSUInt32ToFloat32)
+
+    LAsmJSUInt32ToFloat32(const LAllocation &input) {
+        setOperand(0, input);
+    }
+};
+
+class LAsmJSLoadFuncPtr : public LInstructionHelper<1, 1, 1>
+{
+  public:
+    LIR_HEADER(AsmJSLoadFuncPtr);
+    LAsmJSLoadFuncPtr(const LAllocation &index, const LDefinition &temp) {
+        setOperand(0, index);
+        setTemp(0, temp);
+    }
+    MAsmJSLoadFuncPtr *mir() const {
+        return mir_->toAsmJSLoadFuncPtr();
+    }
+    const LAllocation *index() {
+        return getOperand(0);
+    }
+    const LDefinition *temp() {
+        return getTemp(0);
+    }
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* jit_x64_LIR_x64_h */