Move V8 to external/v8

Change-Id: If68025d67453785a651c5dfb34fad298c16676a4
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
new file mode 100644
index 0000000..adc136a
--- /dev/null
+++ b/src/x64/macro-assembler-x64.h
@@ -0,0 +1,694 @@
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_X64_MACRO_ASSEMBLER_X64_H_
+#define V8_X64_MACRO_ASSEMBLER_X64_H_
+
+#include "assembler.h"
+
+namespace v8 {
+namespace internal {
+
+// Default scratch register used by MacroAssembler (and other code that needs
+// a spare register). The register isn't callee save, and not used by the
+// function calling convention.
+static const Register kScratchRegister = r10;
+
+// Forward declaration.
+class JumpTarget;
+
+struct SmiIndex {
+  SmiIndex(Register index_register, ScaleFactor scale)
+      : reg(index_register),
+        scale(scale) {}
+  Register reg;
+  ScaleFactor scale;
+};
+
+// MacroAssembler implements a collection of frequently used macros.
+class MacroAssembler: public Assembler {
+ public:
+  MacroAssembler(void* buffer, int size);
+
+  void LoadRoot(Register destination, Heap::RootListIndex index);
+  void CompareRoot(Register with, Heap::RootListIndex index);
+  void CompareRoot(Operand with, Heap::RootListIndex index);
+  void PushRoot(Heap::RootListIndex index);
+
+  // ---------------------------------------------------------------------------
+  // GC Support
+
+  // Set the remembered set bit for [object+offset].
+  // object is the object being stored into, value is the object being stored.
+  // If offset is zero, then the scratch register contains the array index into
+  // the elements array represented as a Smi.
+  // All registers are clobbered by the operation.
+  void RecordWrite(Register object,
+                   int offset,
+                   Register value,
+                   Register scratch);
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  // ---------------------------------------------------------------------------
+  // Debugger Support
+
+  void SaveRegistersToMemory(RegList regs);
+  void RestoreRegistersFromMemory(RegList regs);
+  void PushRegistersFromMemory(RegList regs);
+  void PopRegistersToMemory(RegList regs);
+  void CopyRegistersFromStackToMemory(Register base,
+                                      Register scratch,
+                                      RegList regs);
+#endif
+
+  // ---------------------------------------------------------------------------
+  // Activation frames
+
+  void EnterInternalFrame() { EnterFrame(StackFrame::INTERNAL); }
+  void LeaveInternalFrame() { LeaveFrame(StackFrame::INTERNAL); }
+
+  void EnterConstructFrame() { EnterFrame(StackFrame::CONSTRUCT); }
+  void LeaveConstructFrame() { LeaveFrame(StackFrame::CONSTRUCT); }
+
+  // Enter specific kind of exit frame; either EXIT or
+  // EXIT_DEBUG. Expects the number of arguments in register rax and
+  // sets up the number of arguments in register rdi and the pointer
+  // to the first argument in register rsi.
+  void EnterExitFrame(StackFrame::Type type, int result_size = 1);
+
+  // Leave the current exit frame. Expects/provides the return value in
+  // register rax:rdx (untouched) and the pointer to the first
+  // argument in register rsi.
+  void LeaveExitFrame(StackFrame::Type type, int result_size = 1);
+
+
+  // ---------------------------------------------------------------------------
+  // JavaScript invokes
+
+  // Invoke the JavaScript function code by either calling or jumping.
+  void InvokeCode(Register code,
+                  const ParameterCount& expected,
+                  const ParameterCount& actual,
+                  InvokeFlag flag);
+
+  void InvokeCode(Handle<Code> code,
+                  const ParameterCount& expected,
+                  const ParameterCount& actual,
+                  RelocInfo::Mode rmode,
+                  InvokeFlag flag);
+
+  // Invoke the JavaScript function in the given register. Changes the
+  // current context to the context in the function before invoking.
+  void InvokeFunction(Register function,
+                      const ParameterCount& actual,
+                      InvokeFlag flag);
+
+  // Invoke specified builtin JavaScript function. Adds an entry to
+  // the unresolved list if the name does not resolve.
+  void InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag);
+
+  // Store the code object for the given builtin in the target register.
+  void GetBuiltinEntry(Register target, Builtins::JavaScript id);
+
+
+  // ---------------------------------------------------------------------------
+  // Smi tagging, untagging and operations on tagged smis.
+
+  // Conversions between tagged smi values and non-tagged integer values.
+
+  // Tag an integer value. The result must be known to be a valid smi value.
+  // Only uses the low 32 bits of the src register.
+  void Integer32ToSmi(Register dst, Register src);
+
+  // Tag an integer value if possible, or jump the integer value cannot be
+  // represented as a smi. Only uses the low 32 bit of the src registers.
+  void Integer32ToSmi(Register dst, Register src, Label* on_overflow);
+
+  // Adds constant to src and tags the result as a smi.
+  // Result must be a valid smi.
+  void Integer64AddToSmi(Register dst, Register src, int constant);
+
+  // Convert smi to 32-bit integer. I.e., not sign extended into
+  // high 32 bits of destination.
+  void SmiToInteger32(Register dst, Register src);
+
+  // Convert smi to 64-bit integer (sign extended if necessary).
+  void SmiToInteger64(Register dst, Register src);
+
+  // Multiply a positive smi's integer value by a power of two.
+  // Provides result as 64-bit integer value.
+  void PositiveSmiTimesPowerOfTwoToInteger64(Register dst,
+                                             Register src,
+                                             int power);
+
+  // Functions performing a check on a known or potential smi. Returns
+  // a condition that is satisfied if the check is successful.
+
+  // Is the value a tagged smi.
+  Condition CheckSmi(Register src);
+
+  // Is the value not a tagged smi.
+  Condition CheckNotSmi(Register src);
+
+  // Is the value a positive tagged smi.
+  Condition CheckPositiveSmi(Register src);
+
+  // Is the value not a positive tagged smi.
+  Condition CheckNotPositiveSmi(Register src);
+
+  // Are both values are tagged smis.
+  Condition CheckBothSmi(Register first, Register second);
+
+  // Is one of the values not a tagged smi.
+  Condition CheckNotBothSmi(Register first, Register second);
+
+  // Is the value the minimum smi value (since we are using
+  // two's complement numbers, negating the value is known to yield
+  // a non-smi value).
+  Condition CheckIsMinSmi(Register src);
+
+  // Check whether a tagged smi is equal to a constant.
+  Condition CheckSmiEqualsConstant(Register src, int constant);
+
+  // Check whether a tagged smi is greater than or equal to a constant.
+  Condition CheckSmiGreaterEqualsConstant(Register src, int constant);
+
+  // Checks whether an 32-bit integer value is a valid for conversion
+  // to a smi.
+  Condition CheckInteger32ValidSmiValue(Register src);
+
+  // Test-and-jump functions. Typically combines a check function
+  // above with a conditional jump.
+
+  // Jump if the value cannot be represented by a smi.
+  void JumpIfNotValidSmiValue(Register src, Label* on_invalid);
+
+  // Jump to label if the value is a tagged smi.
+  void JumpIfSmi(Register src, Label* on_smi);
+
+  // Jump to label if the value is not a tagged smi.
+  void JumpIfNotSmi(Register src, Label* on_not_smi);
+
+  // Jump to label if the value is not a positive tagged smi.
+  void JumpIfNotPositiveSmi(Register src, Label* on_not_smi);
+
+  // Jump to label if the value is a tagged smi with value equal
+  // to the constant.
+  void JumpIfSmiEqualsConstant(Register src, int constant, Label* on_equals);
+
+  // Jump to label if the value is a tagged smi with value greater than or equal
+  // to the constant.
+  void JumpIfSmiGreaterEqualsConstant(Register src,
+                                      int constant,
+                                      Label* on_equals);
+
+  // Jump if either or both register are not smi values.
+  void JumpIfNotBothSmi(Register src1, Register src2, Label* on_not_both_smi);
+
+  // Operations on tagged smi values.
+
+  // Smis represent a subset of integers. The subset is always equivalent to
+  // a two's complement interpretation of a fixed number of bits.
+
+  // Optimistically adds an integer constant to a supposed smi.
+  // If the src is not a smi, or the result is not a smi, jump to
+  // the label.
+  void SmiTryAddConstant(Register dst,
+                         Register src,
+                         int32_t constant,
+                         Label* on_not_smi_result);
+
+  // Add an integer constant to a tagged smi, giving a tagged smi as result,
+  // or jumping to a label if the result cannot be represented by a smi.
+  // If the label is NULL, no testing on the result is done.
+  void SmiAddConstant(Register dst,
+                      Register src,
+                      int32_t constant,
+                      Label* on_not_smi_result);
+
+  // Subtract an integer constant from a tagged smi, giving a tagged smi as
+  // result, or jumping to a label if the result cannot be represented by a smi.
+  // If the label is NULL, no testing on the result is done.
+  void SmiSubConstant(Register dst,
+                      Register src,
+                      int32_t constant,
+                      Label* on_not_smi_result);
+
+  // Negating a smi can give a negative zero or too large positive value.
+  void SmiNeg(Register dst,
+              Register src,
+              Label* on_not_smi_result);
+
+  // Adds smi values and return the result as a smi.
+  // If dst is src1, then src1 will be destroyed, even if
+  // the operation is unsuccessful.
+  void SmiAdd(Register dst,
+              Register src1,
+              Register src2,
+              Label* on_not_smi_result);
+
+  // Subtracts smi values and return the result as a smi.
+  // If dst is src1, then src1 will be destroyed, even if
+  // the operation is unsuccessful.
+  void SmiSub(Register dst,
+              Register src1,
+              Register src2,
+              Label* on_not_smi_result);
+
+  // Multiplies smi values and return the result as a smi,
+  // if possible.
+  // If dst is src1, then src1 will be destroyed, even if
+  // the operation is unsuccessful.
+  void SmiMul(Register dst,
+              Register src1,
+              Register src2,
+              Label* on_not_smi_result);
+
+  // Divides one smi by another and returns the quotient.
+  // Clobbers rax and rdx registers.
+  void SmiDiv(Register dst,
+              Register src1,
+              Register src2,
+              Label* on_not_smi_result);
+
+  // Divides one smi by another and returns the remainder.
+  // Clobbers rax and rdx registers.
+  void SmiMod(Register dst,
+              Register src1,
+              Register src2,
+              Label* on_not_smi_result);
+
+  // Bitwise operations.
+  void SmiNot(Register dst, Register src);
+  void SmiAnd(Register dst, Register src1, Register src2);
+  void SmiOr(Register dst, Register src1, Register src2);
+  void SmiXor(Register dst, Register src1, Register src2);
+  void SmiAndConstant(Register dst, Register src1, int constant);
+  void SmiOrConstant(Register dst, Register src1, int constant);
+  void SmiXorConstant(Register dst, Register src1, int constant);
+
+  void SmiShiftLeftConstant(Register dst,
+                            Register src,
+                            int shift_value,
+                            Label* on_not_smi_result);
+  void SmiShiftLogicalRightConstant(Register dst,
+                                  Register src,
+                                  int shift_value,
+                                  Label* on_not_smi_result);
+  void SmiShiftArithmeticRightConstant(Register dst,
+                                       Register src,
+                                       int shift_value);
+
+  // Shifts a smi value to the left, and returns the result if that is a smi.
+  // Uses and clobbers rcx, so dst may not be rcx.
+  void SmiShiftLeft(Register dst,
+                    Register src1,
+                    Register src2,
+                    Label* on_not_smi_result);
+  // Shifts a smi value to the right, shifting in zero bits at the top, and
+  // returns the unsigned intepretation of the result if that is a smi.
+  // Uses and clobbers rcx, so dst may not be rcx.
+  void SmiShiftLogicalRight(Register dst,
+                          Register src1,
+                          Register src2,
+                          Label* on_not_smi_result);
+  // Shifts a smi value to the right, sign extending the top, and
+  // returns the signed intepretation of the result. That will always
+  // be a valid smi value, since it's numerically smaller than the
+  // original.
+  // Uses and clobbers rcx, so dst may not be rcx.
+  void SmiShiftArithmeticRight(Register dst,
+                               Register src1,
+                               Register src2);
+
+  // Specialized operations
+
+  // Select the non-smi register of two registers where exactly one is a
+  // smi. If neither are smis, jump to the failure label.
+  void SelectNonSmi(Register dst,
+                    Register src1,
+                    Register src2,
+                    Label* on_not_smis);
+
+  // Converts, if necessary, a smi to a combination of number and
+  // multiplier to be used as a scaled index.
+  // The src register contains a *positive* smi value. The shift is the
+  // power of two to multiply the index value by (e.g.
+  // to index by smi-value * kPointerSize, pass the smi and kPointerSizeLog2).
+  // The returned index register may be either src or dst, depending
+  // on what is most efficient. If src and dst are different registers,
+  // src is always unchanged.
+  SmiIndex SmiToIndex(Register dst, Register src, int shift);
+
+  // Converts a positive smi to a negative index.
+  SmiIndex SmiToNegativeIndex(Register dst, Register src, int shift);
+
+  // ---------------------------------------------------------------------------
+  // Macro instructions
+
+  // Expression support
+  void Set(Register dst, int64_t x);
+  void Set(const Operand& dst, int64_t x);
+
+  // Handle support
+  bool IsUnsafeSmi(Smi* value);
+  bool IsUnsafeSmi(Handle<Object> value) {
+    return IsUnsafeSmi(Smi::cast(*value));
+  }
+
+  void LoadUnsafeSmi(Register dst, Smi* source);
+  void LoadUnsafeSmi(Register dst, Handle<Object> source) {
+    LoadUnsafeSmi(dst, Smi::cast(*source));
+  }
+
+  void Move(Register dst, Handle<Object> source);
+  void Move(const Operand& dst, Handle<Object> source);
+  void Cmp(Register dst, Handle<Object> source);
+  void Cmp(const Operand& dst, Handle<Object> source);
+  void Push(Handle<Object> source);
+  void Push(Smi* smi);
+
+  // Control Flow
+  void Jump(Address destination, RelocInfo::Mode rmode);
+  void Jump(ExternalReference ext);
+  void Jump(Handle<Code> code_object, RelocInfo::Mode rmode);
+
+  void Call(Address destination, RelocInfo::Mode rmode);
+  void Call(ExternalReference ext);
+  void Call(Handle<Code> code_object, RelocInfo::Mode rmode);
+
+  // Compare object type for heap object.
+  // Always use unsigned comparisons: above and below, not less and greater.
+  // Incoming register is heap_object and outgoing register is map.
+  // They may be the same register, and may be kScratchRegister.
+  void CmpObjectType(Register heap_object, InstanceType type, Register map);
+
+  // Compare instance type for map.
+  // Always use unsigned comparisons: above and below, not less and greater.
+  void CmpInstanceType(Register map, InstanceType type);
+
+  // FCmp is similar to integer cmp, but requires unsigned
+  // jcc instructions (je, ja, jae, jb, jbe, je, and jz).
+  void FCmp();
+
+  // ---------------------------------------------------------------------------
+  // Exception handling
+
+  // Push a new try handler and link into try handler chain.  The return
+  // address must be pushed before calling this helper.
+  void PushTryHandler(CodeLocation try_location, HandlerType type);
+
+
+  // ---------------------------------------------------------------------------
+  // Inline caching support
+
+  // Generates code that verifies that the maps of objects in the
+  // prototype chain of object hasn't changed since the code was
+  // generated and branches to the miss label if any map has. If
+  // necessary the function also generates code for security check
+  // in case of global object holders. The scratch and holder
+  // registers are always clobbered, but the object register is only
+  // clobbered if it the same as the holder register. The function
+  // returns a register containing the holder - either object_reg or
+  // holder_reg.
+  Register CheckMaps(JSObject* object, Register object_reg,
+                     JSObject* holder, Register holder_reg,
+                     Register scratch, Label* miss);
+
+  // Generate code for checking access rights - used for security checks
+  // on access to global objects across environments. The holder register
+  // is left untouched, but the scratch register and kScratchRegister,
+  // which must be different, are clobbered.
+  void CheckAccessGlobalProxy(Register holder_reg,
+                              Register scratch,
+                              Label* miss);
+
+
+  // ---------------------------------------------------------------------------
+  // Allocation support
+
+  // Allocate an object in new space. If the new space is exhausted control
+  // continues at the gc_required label. The allocated object is returned in
+  // result and end of the new object is returned in result_end. The register
+  // scratch can be passed as no_reg in which case an additional object
+  // reference will be added to the reloc info. The returned pointers in result
+  // and result_end have not yet been tagged as heap objects. If
+  // result_contains_top_on_entry is true the content of result is known to be
+  // the allocation top on entry (could be result_end from a previous call to
+  // AllocateInNewSpace). If result_contains_top_on_entry is true scratch
+  // should be no_reg as it is never used.
+  void AllocateInNewSpace(int object_size,
+                          Register result,
+                          Register result_end,
+                          Register scratch,
+                          Label* gc_required,
+                          AllocationFlags flags);
+
+  void AllocateInNewSpace(int header_size,
+                          ScaleFactor element_size,
+                          Register element_count,
+                          Register result,
+                          Register result_end,
+                          Register scratch,
+                          Label* gc_required,
+                          AllocationFlags flags);
+
+  void AllocateInNewSpace(Register object_size,
+                          Register result,
+                          Register result_end,
+                          Register scratch,
+                          Label* gc_required,
+                          AllocationFlags flags);
+
+  // Undo allocation in new space. The object passed and objects allocated after
+  // it will no longer be allocated. Make sure that no pointers are left to the
+  // object(s) no longer allocated as they would be invalid when allocation is
+  // un-done.
+  void UndoAllocationInNewSpace(Register object);
+
+  // ---------------------------------------------------------------------------
+  // Support functions.
+
+  // Check if result is zero and op is negative.
+  void NegativeZeroTest(Register result, Register op, Label* then_label);
+
+  // Check if result is zero and op is negative in code using jump targets.
+  void NegativeZeroTest(CodeGenerator* cgen,
+                        Register result,
+                        Register op,
+                        JumpTarget* then_target);
+
+  // Check if result is zero and any of op1 and op2 are negative.
+  // Register scratch is destroyed, and it must be different from op2.
+  void NegativeZeroTest(Register result, Register op1, Register op2,
+                        Register scratch, Label* then_label);
+
+  // Try to get function prototype of a function and puts the value in
+  // the result register. Checks that the function really is a
+  // function and jumps to the miss label if the fast checks fail. The
+  // function register will be untouched; the other register may be
+  // clobbered.
+  void TryGetFunctionPrototype(Register function,
+                               Register result,
+                               Label* miss);
+
+  // Generates code for reporting that an illegal operation has
+  // occurred.
+  void IllegalOperation(int num_arguments);
+
+  // ---------------------------------------------------------------------------
+  // Runtime calls
+
+  // Call a code stub.
+  void CallStub(CodeStub* stub);
+
+  // Return from a code stub after popping its arguments.
+  void StubReturn(int argc);
+
+  // Call a runtime routine.
+  // Eventually this should be used for all C calls.
+  void CallRuntime(Runtime::Function* f, int num_arguments);
+
+  // Convenience function: Same as above, but takes the fid instead.
+  void CallRuntime(Runtime::FunctionId id, int num_arguments);
+
+  // Tail call of a runtime routine (jump).
+  // Like JumpToRuntime, but also takes care of passing the number
+  // of arguments.
+  void TailCallRuntime(const ExternalReference& ext,
+                       int num_arguments,
+                       int result_size);
+
+  // Jump to a runtime routine.
+  void JumpToRuntime(const ExternalReference& ext, int result_size);
+
+
+  // ---------------------------------------------------------------------------
+  // Utilities
+
+  void Ret();
+
+  struct Unresolved {
+    int pc;
+    uint32_t flags;  // see Bootstrapper::FixupFlags decoders/encoders.
+    const char* name;
+  };
+  List<Unresolved>* unresolved() { return &unresolved_; }
+
+  Handle<Object> CodeObject() { return code_object_; }
+
+
+  // ---------------------------------------------------------------------------
+  // StatsCounter support
+
+  void SetCounter(StatsCounter* counter, int value);
+  void IncrementCounter(StatsCounter* counter, int value);
+  void DecrementCounter(StatsCounter* counter, int value);
+
+
+  // ---------------------------------------------------------------------------
+  // Debugging
+
+  // Calls Abort(msg) if the condition cc is not satisfied.
+  // Use --debug_code to enable.
+  void Assert(Condition cc, const char* msg);
+
+  // Like Assert(), but always enabled.
+  void Check(Condition cc, const char* msg);
+
+  // Print a message to stdout and abort execution.
+  void Abort(const char* msg);
+
+  // Verify restrictions about code generated in stubs.
+  void set_generating_stub(bool value) { generating_stub_ = value; }
+  bool generating_stub() { return generating_stub_; }
+  void set_allow_stub_calls(bool value) { allow_stub_calls_ = value; }
+  bool allow_stub_calls() { return allow_stub_calls_; }
+
+ private:
+  List<Unresolved> unresolved_;
+  bool generating_stub_;
+  bool allow_stub_calls_;
+  Handle<Object> code_object_;  // This handle will be patched with the code
+                                // object on installation.
+
+  // Helper functions for generating invokes.
+  void InvokePrologue(const ParameterCount& expected,
+                      const ParameterCount& actual,
+                      Handle<Code> code_constant,
+                      Register code_register,
+                      Label* done,
+                      InvokeFlag flag);
+
+  // Prepares for a call or jump to a builtin by doing two things:
+  // 1. Emits code that fetches the builtin's function object from the context
+  //    at runtime, and puts it in the register rdi.
+  // 2. Fetches the builtin's code object, and returns it in a handle, at
+  //    compile time, so that later code can emit instructions to jump or call
+  //    the builtin directly.  If the code object has not yet been created, it
+  //    returns the builtin code object for IllegalFunction, and sets the
+  //    output parameter "resolved" to false.  Code that uses the return value
+  //    should then add the address and the builtin name to the list of fixups
+  //    called unresolved_, which is fixed up by the bootstrapper.
+  Handle<Code> ResolveBuiltin(Builtins::JavaScript id, bool* resolved);
+
+  // Activation support.
+  void EnterFrame(StackFrame::Type type);
+  void LeaveFrame(StackFrame::Type type);
+
+  // Allocation support helpers.
+  void LoadAllocationTopHelper(Register result,
+                               Register result_end,
+                               Register scratch,
+                               AllocationFlags flags);
+  void UpdateAllocationTopHelper(Register result_end, Register scratch);
+};
+
+
+// The code patcher is used to patch (typically) small parts of code e.g. for
+// debugging and other types of instrumentation. When using the code patcher
+// the exact number of bytes specified must be emitted. Is not legal to emit
+// relocation information. If any of these constraints are violated it causes
+// an assertion.
+class CodePatcher {
+ public:
+  CodePatcher(byte* address, int size);
+  virtual ~CodePatcher();
+
+  // Macro assembler to emit code.
+  MacroAssembler* masm() { return &masm_; }
+
+ private:
+  byte* address_;  // The address of the code being patched.
+  int size_;  // Number of bytes of the expected patch size.
+  MacroAssembler masm_;  // Macro assembler used to generate the code.
+};
+
+
+// -----------------------------------------------------------------------------
+// Static helper functions.
+
+// Generate an Operand for loading a field from an object.
+static inline Operand FieldOperand(Register object, int offset) {
+  return Operand(object, offset - kHeapObjectTag);
+}
+
+
+// Generate an Operand for loading an indexed field from an object.
+static inline Operand FieldOperand(Register object,
+                                   Register index,
+                                   ScaleFactor scale,
+                                   int offset) {
+  return Operand(object, index, scale, offset - kHeapObjectTag);
+}
+
+
+#ifdef GENERATED_CODE_COVERAGE
+extern void LogGeneratedCodeCoverage(const char* file_line);
+#define CODE_COVERAGE_STRINGIFY(x) #x
+#define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
+#define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
+#define ACCESS_MASM(masm) {                                               \
+    byte* x64_coverage_function =                                         \
+        reinterpret_cast<byte*>(FUNCTION_ADDR(LogGeneratedCodeCoverage)); \
+    masm->pushfd();                                                       \
+    masm->pushad();                                                       \
+    masm->push(Immediate(reinterpret_cast<int>(&__FILE_LINE__)));         \
+    masm->call(x64_coverage_function, RelocInfo::RUNTIME_ENTRY);          \
+    masm->pop(rax);                                                       \
+    masm->popad();                                                        \
+    masm->popfd();                                                        \
+  }                                                                       \
+  masm->
+#else
+#define ACCESS_MASM(masm) masm->
+#endif
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_X64_MACRO_ASSEMBLER_X64_H_