CSE2410 Fall 2014 Bounce

// Copyright 2012 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

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//       copyright notice, this list of conditions and the following

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//

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#ifndef V8_X64_MACRO_ASSEMBLER_X64_H_

#define V8_X64_MACRO_ASSEMBLER_X64_H_

#include "assembler.h"

#include "frames.h"

#include "v8globals.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.

const Register kScratchRegister = { 10 };      // r10.

const Register kSmiConstantRegister = { 12 };  // r12 (callee save).

const Register kRootRegister = { 13 };         // r13 (callee save).

// Value of smi in kSmiConstantRegister.

const int kSmiConstantRegisterValue = 1;

// Actual value of root register is offset from the root array's start

// to take advantage of negitive 8-bit displacement values.

const int kRootRegisterBias = 128;

// Convenience for platform-independent signatures.

typedef Operand MemOperand;

enum RememberedSetAction { EMIT_REMEMBERED_SET, OMIT_REMEMBERED_SET };

enum SmiCheck { INLINE_SMI_CHECK, OMIT_SMI_CHECK };

bool AreAliased(Register r1, Register r2, Register r3, Register r4);

// 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:

  // The isolate parameter can be NULL if the macro assembler should

  // not use isolate-dependent functionality. In this case, it's the

  // responsibility of the caller to never invoke such function on the

  // macro assembler.

  MacroAssembler(Isolate* isolate, void* buffer, int size);

  // Prevent the use of the RootArray during the lifetime of this

  // scope object.

  class NoRootArrayScope BASE_EMBEDDED {

   public:

    explicit NoRootArrayScope(MacroAssembler* assembler)

        : variable_(&assembler->root_array_available_),

          old_value_(assembler->root_array_available_) {

      assembler->root_array_available_ = false;

    }

    ~NoRootArrayScope() {

      *variable_ = old_value_;

    }

   private:

    bool* variable_;

    bool old_value_;

  };

  // Operand pointing to an external reference.

  // May emit code to set up the scratch register. The operand is

  // only guaranteed to be correct as long as the scratch register

  // isn't changed.

  // If the operand is used more than once, use a scratch register

  // that is guaranteed not to be clobbered.

  Operand ExternalOperand(ExternalReference reference,

                          Register scratch = kScratchRegister);

  // Loads and stores the value of an external reference.

  // Special case code for load and store to take advantage of

  // load_rax/store_rax if possible/necessary.

  // For other operations, just use:

  //   Operand operand = ExternalOperand(extref);

  //   operation(operand, ..);

  void Load(Register destination, ExternalReference source);

  void Store(ExternalReference destination, Register source);

  // Loads the address of the external reference into the destination

  // register.

  void LoadAddress(Register destination, ExternalReference source);

  // Returns the size of the code generated by LoadAddress.

  // Used by CallSize(ExternalReference) to find the size of a call.

  int LoadAddressSize(ExternalReference source);

  // Pushes the address of the external reference onto the stack.

  void PushAddress(ExternalReference source);

  // Operations on roots in the root-array.

  void LoadRoot(Register destination, Heap::RootListIndex index);

  void StoreRoot(Register source, Heap::RootListIndex index);

  // Load a root value where the index (or part of it) is variable.

  // The variable_offset register is added to the fixed_offset value

  // to get the index into the root-array.

  void LoadRootIndexed(Register destination,

                       Register variable_offset,

                       int fixed_offset);

  void CompareRoot(Register with, Heap::RootListIndex index);

  void CompareRoot(const Operand& with, Heap::RootListIndex index);

  void PushRoot(Heap::RootListIndex index);

  // These functions do not arrange the registers in any particular order so

  // they are not useful for calls that can cause a GC.  The caller can

  // exclude up to 3 registers that do not need to be saved and restored.

  void PushCallerSaved(SaveFPRegsMode fp_mode,

                       Register exclusion1 = no_reg,

                       Register exclusion2 = no_reg,

                       Register exclusion3 = no_reg);

  void PopCallerSaved(SaveFPRegsMode fp_mode,

                      Register exclusion1 = no_reg,

                      Register exclusion2 = no_reg,

                      Register exclusion3 = no_reg);

// ---------------------------------------------------------------------------

// GC Support

  enum RememberedSetFinalAction {

    kReturnAtEnd,

    kFallThroughAtEnd

  };

  // Record in the remembered set the fact that we have a pointer to new space

  // at the address pointed to by the addr register.  Only works if addr is not

  // in new space.

  void RememberedSetHelper(Register object,  // Used for debug code.

                           Register addr,

                           Register scratch,

                           SaveFPRegsMode save_fp,

                           RememberedSetFinalAction and_then);

  void CheckPageFlag(Register object,

                     Register scratch,

                     int mask,

                     Condition cc,

                     Label* condition_met,

                     Label::Distance condition_met_distance = Label::kFar);

  void CheckMapDeprecated(Handle<Map> map,

                          Register scratch,

                          Label* if_deprecated);

  // Check if object is in new space.  Jumps if the object is not in new space.

  // The register scratch can be object itself, but scratch will be clobbered.

  void JumpIfNotInNewSpace(Register object,

                           Register scratch,

                           Label* branch,

                           Label::Distance distance = Label::kFar) {

    InNewSpace(object, scratch, not_equal, branch, distance);

  }

  // Check if object is in new space.  Jumps if the object is in new space.

  // The register scratch can be object itself, but it will be clobbered.

  void JumpIfInNewSpace(Register object,

                        Register scratch,

                        Label* branch,

                        Label::Distance distance = Label::kFar) {

    InNewSpace(object, scratch, equal, branch, distance);

  }

  // Check if an object has the black incremental marking color.  Also uses rcx!

  void JumpIfBlack(Register object,

                   Register scratch0,

                   Register scratch1,

                   Label* on_black,

                   Label::Distance on_black_distance = Label::kFar);

  // Detects conservatively whether an object is data-only, i.e. it does need to

  // be scanned by the garbage collector.

  void JumpIfDataObject(Register value,

                        Register scratch,

                        Label* not_data_object,

                        Label::Distance not_data_object_distance);

  // Checks the color of an object.  If the object is already grey or black

  // then we just fall through, since it is already live.  If it is white and

  // we can determine that it doesn't need to be scanned, then we just mark it

  // black and fall through.  For the rest we jump to the label so the

  // incremental marker can fix its assumptions.

  void EnsureNotWhite(Register object,

                      Register scratch1,

                      Register scratch2,

                      Label* object_is_white_and_not_data,

                      Label::Distance distance);

  // Notify the garbage collector that we wrote a pointer into an object.

  // |object| is the object being stored into, |value| is the object being

  // stored.  value and scratch registers are clobbered by the operation.

  // The offset is the offset from the start of the object, not the offset from

  // the tagged HeapObject pointer.  For use with FieldOperand(reg, off).

  void RecordWriteField(

      Register object,

      int offset,

      Register value,

      Register scratch,

      SaveFPRegsMode save_fp,

      RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,

      SmiCheck smi_check = INLINE_SMI_CHECK);

  // As above, but the offset has the tag presubtracted.  For use with

  // Operand(reg, off).

  void RecordWriteContextSlot(

      Register context,

      int offset,

      Register value,

      Register scratch,

      SaveFPRegsMode save_fp,

      RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,

      SmiCheck smi_check = INLINE_SMI_CHECK) {

    RecordWriteField(context,

                     offset + kHeapObjectTag,

                     value,

                     scratch,

                     save_fp,

                     remembered_set_action,

                     smi_check);

  }

  // Notify the garbage collector that we wrote a pointer into a fixed array.

  // |array| is the array being stored into, |value| is the

  // object being stored.  |index| is the array index represented as a non-smi.

  // All registers are clobbered by the operation RecordWriteArray

  // filters out smis so it does not update the write barrier if the

  // value is a smi.

  void RecordWriteArray(

      Register array,

      Register value,

      Register index,

      SaveFPRegsMode save_fp,

      RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,

      SmiCheck smi_check = INLINE_SMI_CHECK);

  // For page containing |object| mark region covering |address|

  // dirty. |object| is the object being stored into, |value| is the

  // object being stored. The address and value registers are clobbered by the

  // operation.  RecordWrite filters out smis so it does not update

  // the write barrier if the value is a smi.

  void RecordWrite(

      Register object,

      Register address,

      Register value,

      SaveFPRegsMode save_fp,

      RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,

      SmiCheck smi_check = INLINE_SMI_CHECK);

#ifdef ENABLE_DEBUGGER_SUPPORT

  // ---------------------------------------------------------------------------

  // Debugger Support

  void DebugBreak();

#endif

  // Generates function and stub prologue code.

  void Prologue(PrologueFrameMode frame_mode);

  // Enter specific kind of exit frame; either in normal or

  // debug mode. 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.

  //

  // Allocates arg_stack_space * kPointerSize memory (not GCed) on the stack

  // accessible via StackSpaceOperand.

  void EnterExitFrame(int arg_stack_space = 0, bool save_doubles = false);

  // Enter specific kind of exit frame. Allocates arg_stack_space * kPointerSize

  // memory (not GCed) on the stack accessible via StackSpaceOperand.

  void EnterApiExitFrame(int arg_stack_space);

  // 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(bool save_doubles = false);

  // Leave the current exit frame. Expects/provides the return value in

  // register rax (untouched).

  void LeaveApiExitFrame(bool restore_context);

  // Push and pop the registers that can hold pointers.

  void PushSafepointRegisters() { Pushad(); }

  void PopSafepointRegisters() { Popad(); }

  // Store the value in register src in the safepoint register stack

  // slot for register dst.

  void StoreToSafepointRegisterSlot(Register dst, const Immediate& imm);

  void StoreToSafepointRegisterSlot(Register dst, Register src);

  void LoadFromSafepointRegisterSlot(Register dst, Register src);

  void InitializeRootRegister() {

    ExternalReference roots_array_start =

        ExternalReference::roots_array_start(isolate());

    movq(kRootRegister, roots_array_start);

    addq(kRootRegister, Immediate(kRootRegisterBias));

  }

  // ---------------------------------------------------------------------------

  // JavaScript invokes

  // Set up call kind marking in rcx. The method takes rcx as an

  // explicit first parameter to make the code more readable at the

  // call sites.

  void SetCallKind(Register dst, CallKind kind);

  // Invoke the JavaScript function code by either calling or jumping.

  void InvokeCode(Register code,

                  const ParameterCount& expected,

                  const ParameterCount& actual,

                  InvokeFlag flag,

                  const CallWrapper& call_wrapper,

                  CallKind call_kind);

  void InvokeCode(Handle<Code> code,

                  const ParameterCount& expected,

                  const ParameterCount& actual,

                  RelocInfo::Mode rmode,

                  InvokeFlag flag,

                  const CallWrapper& call_wrapper,

                  CallKind call_kind);

  // 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,

                      const CallWrapper& call_wrapper,

                      CallKind call_kind);

  void InvokeFunction(Handle<JSFunction> function,

                      const ParameterCount& expected,

                      const ParameterCount& actual,

                      InvokeFlag flag,

                      const CallWrapper& call_wrapper,

                      CallKind call_kind);

  // 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,

                     const CallWrapper& call_wrapper = NullCallWrapper());

  // Store the function for the given builtin in the target register.

  void GetBuiltinFunction(Register target, Builtins::JavaScript id);

  // 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.

  // Support for constant splitting.

  bool IsUnsafeInt(const int32_t x);

  void SafeMove(Register dst, Smi* src);

  void SafePush(Smi* src);

  void InitializeSmiConstantRegister() {

    movq(kSmiConstantRegister,

         reinterpret_cast<uint64_t>(Smi::FromInt(kSmiConstantRegisterValue)),

         RelocInfo::NONE64);

  }

  // 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. Sets the N and Z flags

  // based on the value of the resulting smi.

  void Integer32ToSmi(Register dst, Register src);

  // Stores an integer32 value into a memory field that already holds a smi.

  void Integer32ToSmiField(const Operand& dst, Register src);

  // Adds constant to src and tags the result as a smi.

  // Result must be a valid smi.

  void Integer64PlusConstantToSmi(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);

  void SmiToInteger32(Register dst, const Operand& src);

  // Convert smi to 64-bit integer (sign extended if necessary).

  void SmiToInteger64(Register dst, Register src);

  void SmiToInteger64(Register dst, const Operand& 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);

  // Divide a positive smi's integer value by a power of two.

  // Provides result as 32-bit integer value.

  void PositiveSmiDivPowerOfTwoToInteger32(Register dst,

                                           Register src,

                                           int power);

  // Perform the logical or of two smi values and return a smi value.

  // If either argument is not a smi, jump to on_not_smis and retain

  // the original values of source registers. The destination register

  // may be changed if it's not one of the source registers.

  void SmiOrIfSmis(Register dst,

                   Register src1,

                   Register src2,

                   Label* on_not_smis,

                   Label::Distance near_jump = Label::kFar);

  // Simple comparison of smis.  Both sides must be known smis to use these,

  // otherwise use Cmp.

  void SmiCompare(Register smi1, Register smi2);

  void SmiCompare(Register dst, Smi* src);

  void SmiCompare(Register dst, const Operand& src);

  void SmiCompare(const Operand& dst, Register src);

  void SmiCompare(const Operand& dst, Smi* src);

  // Compare the int32 in src register to the value of the smi stored at dst.

  void SmiCompareInteger32(const Operand& dst, Register src);

  // Sets sign and zero flags depending on value of smi in register.

  void SmiTest(Register src);

  // 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);

  Condition CheckSmi(const Operand& src);

  // Is the value a non-negative tagged smi.

  Condition CheckNonNegativeSmi(Register src);

  // Are both values tagged smis.

  Condition CheckBothSmi(Register first, Register second);

  // Are both values non-negative tagged smis.

  Condition CheckBothNonNegativeSmi(Register first, Register second);

  // Are either value a tagged smi.

  Condition CheckEitherSmi(Register first,

                           Register second,

                           Register scratch = kScratchRegister);

  // 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);

  // Checks whether an 32-bit integer value is a valid for conversion

  // to a smi.

  Condition CheckInteger32ValidSmiValue(Register src);

  // Checks whether an 32-bit unsigned integer value is a valid for

  // conversion to a smi.

  Condition CheckUInteger32ValidSmiValue(Register src);

  // Check whether src is a Smi, and set dst to zero if it is a smi,

  // and to one if it isn't.

  void CheckSmiToIndicator(Register dst, Register src);

  void CheckSmiToIndicator(Register dst, const Operand& 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,

                              Label::Distance near_jump = Label::kFar);

  // Jump if the unsigned integer value cannot be represented by a smi.

  void JumpIfUIntNotValidSmiValue(Register src, Label* on_invalid,

                                  Label::Distance near_jump = Label::kFar);

  // Jump to label if the value is a tagged smi.

  void JumpIfSmi(Register src,

                 Label* on_smi,

                 Label::Distance near_jump = Label::kFar);

  // Jump to label if the value is not a tagged smi.

  void JumpIfNotSmi(Register src,

                    Label* on_not_smi,

                    Label::Distance near_jump = Label::kFar);

  // Jump to label if the value is not a non-negative tagged smi.

  void JumpUnlessNonNegativeSmi(Register src,

                                Label* on_not_smi,

                                Label::Distance near_jump = Label::kFar);

  // Jump to label if the value, which must be a tagged smi, has value equal

  // to the constant.

  void JumpIfSmiEqualsConstant(Register src,

                               Smi* constant,

                               Label* on_equals,

                               Label::Distance near_jump = Label::kFar);

  // Jump if either or both register are not smi values.

  void JumpIfNotBothSmi(Register src1,

                        Register src2,

                        Label* on_not_both_smi,

                        Label::Distance near_jump = Label::kFar);

  // Jump if either or both register are not non-negative smi values.

  void JumpUnlessBothNonNegativeSmi(Register src1, Register src2,

                                    Label* on_not_both_smi,

                                    Label::Distance near_jump = Label::kFar);

  // 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.

  // Add an integer constant to a tagged smi, giving a tagged smi as result.

  // No overflow testing on the result is done.

  void SmiAddConstant(Register dst, Register src, Smi* constant);

  // Add an integer constant to a tagged smi, giving a tagged smi as result.

  // No overflow testing on the result is done.

  void SmiAddConstant(const Operand& dst, Smi* constant);

  // 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.

  void SmiAddConstant(Register dst,

                      Register src,

                      Smi* constant,

                      Label* on_not_smi_result,

                      Label::Distance near_jump = Label::kFar);

  // Subtract an integer constant from a tagged smi, giving a tagged smi as

  // result. No testing on the result is done. Sets the N and Z flags

  // based on the value of the resulting integer.

  void SmiSubConstant(Register dst, Register src, Smi* constant);

  // 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.

  void SmiSubConstant(Register dst,

                      Register src,

                      Smi* constant,

                      Label* on_not_smi_result,

                      Label::Distance near_jump = Label::kFar);

  // Negating a smi can give a negative zero or too large positive value.

  // NOTICE: This operation jumps on success, not failure!

  void SmiNeg(Register dst,

              Register src,

              Label* on_smi_result,

              Label::Distance near_jump = Label::kFar);

  // Adds smi values and return the result as a smi.

  // If dst is src1, then src1 will be destroyed if the operation is

  // successful, otherwise kept intact.

  void SmiAdd(Register dst,

              Register src1,

              Register src2,

              Label* on_not_smi_result,

              Label::Distance near_jump = Label::kFar);

  void SmiAdd(Register dst,

              Register src1,

              const Operand& src2,

              Label* on_not_smi_result,

              Label::Distance near_jump = Label::kFar);

  void SmiAdd(Register dst,

              Register src1,

              Register src2);

  // Subtracts smi values and return the result as a smi.

  // If dst is src1, then src1 will be destroyed if the operation is

  // successful, otherwise kept intact.

  void SmiSub(Register dst,

              Register src1,

              Register src2,

              Label* on_not_smi_result,

              Label::Distance near_jump = Label::kFar);

  void SmiSub(Register dst,

              Register src1,

              const Operand& src2,

              Label* on_not_smi_result,

              Label::Distance near_jump = Label::kFar);

  void SmiSub(Register dst,

              Register src1,

              Register src2);

  void SmiSub(Register dst,

              Register src1,

              const Operand& src2);

  // 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,

              Label::Distance near_jump = Label::kFar);

  // 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,

              Label::Distance near_jump = Label::kFar);

  // 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,

              Label::Distance near_jump = Label::kFar);

  // 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, Smi* constant);

  void SmiOrConstant(Register dst, Register src1, Smi* constant);

  void SmiXorConstant(Register dst, Register src1, Smi* constant);

  void SmiShiftLeftConstant(Register dst,

                            Register src,

                            int shift_value);

  void SmiShiftLogicalRightConstant(Register dst,

                                  Register src,

                                  int shift_value,

                                  Label* on_not_smi_result,

                                  Label::Distance near_jump = Label::kFar);

  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);

  // 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,

                            Label::Distance near_jump = Label::kFar);

  // 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,

                    Label::Distance near_jump = Label::kFar);

  // 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);

  // Add the value of a smi in memory to an int32 register.

  // Sets flags as a normal add.

  void AddSmiField(Register dst, const Operand& src);

  // Basic Smi operations.

  void Move(Register dst, Smi* source) {

    LoadSmiConstant(dst, source);

  }

  void Move(const Operand& dst, Smi* source) {

    Register constant = GetSmiConstant(source);

    movq(dst, constant);

  }

  void Push(Smi* smi);

  // Save away a 64-bit integer on the stack as two 32-bit integers

  // masquerading as smis so that the garbage collector skips visiting them.

  void PushInt64AsTwoSmis(Register src, Register scratch = kScratchRegister);

  // Reconstruct a 64-bit integer from two 32-bit integers masquerading as

  // smis on the top of stack.

  void PopInt64AsTwoSmis(Register dst, Register scratch = kScratchRegister);

  void Test(const Operand& dst, Smi* source);

  // ---------------------------------------------------------------------------

  // String macros.

  // Generate code to do a lookup in the number string cache. If the number in

  // the register object is found in the cache the generated code falls through

  // with the result in the result register. The object and the result register

  // can be the same. If the number is not found in the cache the code jumps to

  // the label not_found with only the content of register object unchanged.

  void LookupNumberStringCache(Register object,

                               Register result,

                               Register scratch1,

                               Register scratch2,

                               Label* not_found);

  // If object is a string, its map is loaded into object_map.

  void JumpIfNotString(Register object,

                       Register object_map,

                       Label* not_string,

                       Label::Distance near_jump = Label::kFar);

  void JumpIfNotBothSequentialAsciiStrings(

      Register first_object,

      Register second_object,

      Register scratch1,

      Register scratch2,

      Label* on_not_both_flat_ascii,

      Label::Distance near_jump = Label::kFar);

  // Check whether the instance type represents a flat ASCII string. Jump to the

  // label if not. If the instance type can be scratched specify same register

  // for both instance type and scratch.

  void JumpIfInstanceTypeIsNotSequentialAscii(

      Register instance_type,

      Register scratch,

      Label*on_not_flat_ascii_string,

      Label::Distance near_jump = Label::kFar);

  void JumpIfBothInstanceTypesAreNotSequentialAscii(

      Register first_object_instance_type,

      Register second_object_instance_type,

      Register scratch1,

      Register scratch2,

      Label* on_fail,

      Label::Distance near_jump = Label::kFar);

  // Checks if the given register or operand is a unique name

  void JumpIfNotUniqueName(Register reg, Label* not_unique_name,

                           Label::Distance distance = Label::kFar);

  void JumpIfNotUniqueName(Operand operand, Label* not_unique_name,

                           Label::Distance distance = Label::kFar);

  // ---------------------------------------------------------------------------

  // Macro instructions.

  // Load/store with specific representation.

  void Load(Register dst, const Operand& src, Representation r);

  void Store(const Operand& dst, Register src, Representation r);

  // Load a register with a long value as efficiently as possible.

  void Set(Register dst, int64_t x);

  void Set(const Operand& dst, int64_t x);

  // cvtsi2sd instruction only writes to the low 64-bit of dst register, which

  // hinders register renaming and makes dependence chains longer. So we use

  // xorps to clear the dst register before cvtsi2sd to solve this issue.

  void Cvtlsi2sd(XMMRegister dst, Register src);

  void Cvtlsi2sd(XMMRegister dst, const Operand& src);

  // Move if the registers are not identical.

  void Move(Register target, Register source);

  // Bit-field support.

  void TestBit(const Operand& dst, int bit_index);

  // Handle support

  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 Cmp(Register dst, Smi* src);

  void Cmp(const Operand& dst, Smi* src);

  void Push(Handle<Object> source);

  // Load a heap object and handle the case of new-space objects by

  // indirecting via a global cell.

  void MoveHeapObject(Register result, Handle<Object> object);

  // Load a global cell into a register.

  void LoadGlobalCell(Register dst, Handle<Cell> cell);

  // Emit code to discard a non-negative number of pointer-sized elements

  // from the stack, clobbering only the rsp register.

  void Drop(int stack_elements);

  void Call(Label* target) { call(target); }

  void Push(Register src) { push(src); }

  void Pop(Register dst) { pop(dst); }

  void PushReturnAddressFrom(Register src) { push(src); }

  void PopReturnAddressTo(Register dst) { pop(dst); }

  void MoveDouble(Register dst, const Operand& src) { movq(dst, src); }

  void MoveDouble(const Operand& dst, Register src) { movq(dst, src); }

  // 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,

            TypeFeedbackId ast_id = TypeFeedbackId::None());

  // The size of the code generated for different call instructions.

  int CallSize(Address destination, RelocInfo::Mode rmode) {

    return kCallSequenceLength;

  }

  int CallSize(ExternalReference ext);

  int CallSize(Handle<Code> code_object) {

    // Code calls use 32-bit relative addressing.

    return kShortCallInstructionLength;

  }

  int CallSize(Register target) {

    // Opcode: REX_opt FF /2 m64

    return (target.high_bit() != 0) ? 3 : 2;

  }

  int CallSize(const Operand& target) {

    // Opcode: REX_opt FF /2 m64

    return (target.requires_rex() ? 2 : 1) + target.operand_size();

  }

  // Emit call to the code we are currently generating.

  void CallSelf() {

    Handle<Code> self(reinterpret_cast<Code**>(CodeObject().location()));

    Call(self, RelocInfo::CODE_TARGET);

  }

  // Non-x64 instructions.

  // Push/pop all general purpose registers.

  // Does not push rsp/rbp nor any of the assembler's special purpose registers

  // (kScratchRegister, kSmiConstantRegister, kRootRegister).

  void Pushad();

  void Popad();

  // Sets the stack as after performing Popad, without actually loading the

  // registers.

  void Dropad();

  // 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);

  // Check if a map for a JSObject indicates that the object has fast elements.

  // Jump to the specified label if it does not.

  void CheckFastElements(Register map,

                         Label* fail,

                         Label::Distance distance = Label::kFar);

  // Check if a map for a JSObject indicates that the object can have both smi

  // and HeapObject elements.  Jump to the specified label if it does not.

  void CheckFastObjectElements(Register map,

                               Label* fail,

                               Label::Distance distance = Label::kFar);

  // Check if a map for a JSObject indicates that the object has fast smi only

  // elements.  Jump to the specified label if it does not.

  void CheckFastSmiElements(Register map,

                            Label* fail,

                            Label::Distance distance = Label::kFar);

  // Check to see if maybe_number can be stored as a double in

  // FastDoubleElements. If it can, store it at the index specified by index in

  // the FastDoubleElements array elements, otherwise jump to fail.  Note that

  // index must not be smi-tagged.

  void StoreNumberToDoubleElements(Register maybe_number,

                                   Register elements,

                                   Register index,

                                   XMMRegister xmm_scratch,

                                   Label* fail,

                                   int elements_offset = 0);

  // Compare an object's map with the specified map and its transitioned

  // elements maps if mode is ALLOW_ELEMENT_TRANSITION_MAPS. FLAGS are set with

  // result of map compare. If multiple map compares are required, the compare

  // sequences branches to early_success.

  void CompareMap(Register obj,

                  Handle<Map> map,

                  Label* early_success);

  // Check if the map of an object is equal to a specified map and branch to

  // label if not. Skip the smi check if not required (object is known to be a

  // heap object). If mode is ALLOW_ELEMENT_TRANSITION_MAPS, then also match

  // against maps that are ElementsKind transition maps of the specified map.

  void CheckMap(Register obj,

                Handle<Map> map,

                Label* fail,

                SmiCheckType smi_check_type);

  // Check if the map of an object is equal to a specified map and branch to a

  // specified target if equal. Skip the smi check if not required (object is

  // known to be a heap object)

  void DispatchMap(Register obj,

                   Register unused,

                   Handle<Map> map,

                   Handle<Code> success,

                   SmiCheckType smi_check_type);

  // Check if the object in register heap_object is a string. Afterwards the

  // register map contains the object map and the register instance_type

  // contains the instance_type. The registers map and instance_type can be the

  // same in which case it contains the instance type afterwards. Either of the

  // registers map and instance_type can be the same as heap_object.

  Condition IsObjectStringType(Register heap_object,

                               Register map,

                               Register instance_type);

  // Check if the object in register heap_object is a name. Afterwards the

  // register map contains the object map and the register instance_type

  // contains the instance_type. The registers map and instance_type can be the

  // same in which case it contains the instance type afterwards. Either of the

  // registers map and instance_type can be the same as heap_object.

  Condition IsObjectNameType(Register heap_object,

                             Register map,

                             Register instance_type);

  // FCmp compares and pops the two values on top of the FPU stack.

  // The flag results are similar to integer cmp, but requires unsigned

  // jcc instructions (je, ja, jae, jb, jbe, je, and jz).

  void FCmp();

  void ClampUint8(Register reg);

  void ClampDoubleToUint8(XMMRegister input_reg,

                          XMMRegister temp_xmm_reg,

                          Register result_reg);

  void SlowTruncateToI(Register result_reg, Register input_reg,

      int offset = HeapNumber::kValueOffset - kHeapObjectTag);

  void TruncateHeapNumberToI(Register result_reg, Register input_reg);

  void TruncateDoubleToI(Register result_reg, XMMRegister input_reg);

  void DoubleToI(Register result_reg, XMMRegister input_reg,

      XMMRegister scratch, MinusZeroMode minus_zero_mode,

      Label* conversion_failed, Label::Distance dst = Label::kFar);

  void TaggedToI(Register result_reg, Register input_reg, XMMRegister temp,

      MinusZeroMode minus_zero_mode, Label* lost_precision,

      Label::Distance dst = Label::kFar);

  void LoadUint32(XMMRegister dst, Register src, XMMRegister scratch);

  void LoadInstanceDescriptors(Register map, Register descriptors);

  void EnumLength(Register dst, Register map);

  void NumberOfOwnDescriptors(Register dst, Register map);

  template<typename Field>

  void DecodeField(Register reg) {

    static const int shift = Field::kShift + kSmiShift;

    static const int mask = Field::kMask >> Field::kShift;

    shr(reg, Immediate(shift));

    and_(reg, Immediate(mask));

    shl(reg, Immediate(kSmiShift));

  }

  // Abort execution if argument is not a number, enabled via --debug-code.

  void AssertNumber(Register object);

  // Abort execution if argument is a smi, enabled via --debug-code.

  void AssertNotSmi(Register object);

  // Abort execution if argument is not a smi, enabled via --debug-code.

  void AssertSmi(Register object);

  void AssertSmi(const Operand& object);

  // Abort execution if a 64 bit register containing a 32 bit payload does not

  // have zeros in the top 32 bits, enabled via --debug-code.

  void AssertZeroExtended(Register reg);

  // Abort execution if argument is not a string, enabled via --debug-code.

  void AssertString(Register object);

  // Abort execution if argument is not a name, enabled via --debug-code.

  void AssertName(Register object);

  // Abort execution if argument is not the root value with the given index,

  // enabled via --debug-code.

  void AssertRootValue(Register src,

                       Heap::RootListIndex root_value_index,

                       BailoutReason reason);

  // ---------------------------------------------------------------------------

  // Exception handling

  // Push a new try handler and link it into try handler chain.

  void PushTryHandler(StackHandler::Kind kind, int handler_index);

  // Unlink the stack handler on top of the stack from the try handler chain.

  void PopTryHandler();

  // Activate the top handler in the try hander chain and pass the

  // thrown value.

  void Throw(Register value);

  // Propagate an uncatchable exception out of the current JS stack.

  void ThrowUncatchable(Register value);

  // ---------------------------------------------------------------------------

  // Inline caching support

  // 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);

  void GetNumberHash(Register r0, Register scratch);

  void LoadFromNumberDictionary(Label* miss,

                                Register elements,

                                Register key,

                                Register r0,

                                Register r1,

                                Register r2,

                                Register result);

  // ---------------------------------------------------------------------------

  // Allocation support

  // Allocate an object in new space or old pointer space. If the given 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). If result_contains_top_on_entry is true scratch

  // should be no_reg as it is never used.

  void Allocate(int object_size,

                Register result,

                Register result_end,

                Register scratch,

                Label* gc_required,

                AllocationFlags flags);

  void Allocate(int header_size,

                ScaleFactor element_size,

                Register element_count,

                Register result,

                Register result_end,

                Register scratch,

                Label* gc_required,

                AllocationFlags flags);

  void Allocate(Register object_size,

                Register result,

                Register result_end,

                Register scratch,

                Label* gc_required,

                AllocationFlags flags);

  // Record a JS object allocation if allocations tracking mode is on.

  void RecordObjectAllocation(Isolate* isolate,

                              Register object,

                              Register object_size);

  void RecordObjectAllocation(Isolate* isolate,

                              Register object,

                              int object_size);

  // 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);

  // Allocate a heap number in new space with undefined value. Returns

  // tagged pointer in result register, or jumps to gc_required if new

  // space is full.

  void AllocateHeapNumber(Register result,

                          Register scratch,

                          Label* gc_required);

  // Allocate a sequential string. All the header fields of the string object

  // are initialized.

  void AllocateTwoByteString(Register result,

                             Register length,

                             Register scratch1,

                             Register scratch2,

                             Register scratch3,

                             Label* gc_required);

  void AllocateAsciiString(Register result,

                           Register length,

                           Register scratch1,

                           Register scratch2,

                           Register scratch3,

                           Label* gc_required);

  // Allocate a raw cons string object. Only the map field of the result is

  // initialized.

  void AllocateTwoByteConsString(Register result,

                          Register scratch1,

                          Register scratch2,

                          Label* gc_required);

  void AllocateAsciiConsString(Register result,

                               Register scratch1,

                               Register scratch2,

                               Label* gc_required);

  // Allocate a raw sliced string object. Only the map field of the result is

  // initialized.

  void AllocateTwoByteSlicedString(Register result,

                            Register scratch1,

                            Register scratch2,

                            Label* gc_required);

  void AllocateAsciiSlicedString(Register result,

                                 Register scratch1,

                                 Register scratch2,

                                 Label* gc_required);

  // ---------------------------------------------------------------------------

  // 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,

                               bool miss_on_bound_function = false);

  // Generates code for reporting that an illegal operation has

  // occurred.

  void IllegalOperation(int num_arguments);

  // Picks out an array index from the hash field.

  // Register use:

  //   hash - holds the index's hash. Clobbered.

  //   index - holds the overwritten index on exit.

  void IndexFromHash(Register hash, Register index);

  // Find the function context up the context chain.

  void LoadContext(Register dst, int context_chain_length);

  // Conditionally load the cached Array transitioned map of type

  // transitioned_kind from the native context if the map in register

  // map_in_out is the cached Array map in the native context of

  // expected_kind.

  void LoadTransitionedArrayMapConditional(

      ElementsKind expected_kind,

      ElementsKind transitioned_kind,

      Register map_in_out,

      Register scratch,

      Label* no_map_match);

  // Load the initial map for new Arrays from a JSFunction.

  void LoadInitialArrayMap(Register function_in,

                           Register scratch,

                           Register map_out,

                           bool can_have_holes);

  // Load the global function with the given index.

  void LoadGlobalFunction(int index, Register function);

  void LoadArrayFunction(Register function);

  // Load the initial map from the global function. The registers

  // function and map can be the same.

  void LoadGlobalFunctionInitialMap(Register function, Register map);

  // ---------------------------------------------------------------------------

  // Runtime calls

  // Call a code stub.

  void CallStub(CodeStub* stub, TypeFeedbackId ast_id = TypeFeedbackId::None());

  // Tail call a code stub (jump).

  void TailCallStub(CodeStub* stub);

  // Return from a code stub after popping its arguments.

  void StubReturn(int argc);

  // Call a runtime routine.

  void CallRuntime(const Runtime::Function* f,

                   int num_arguments,

                   SaveFPRegsMode save_doubles = kDontSaveFPRegs);

  // Call a runtime function and save the value of XMM registers.

  void CallRuntimeSaveDoubles(Runtime::FunctionId id) {

    const Runtime::Function* function = Runtime::FunctionForId(id);

    CallRuntime(function, function->nargs, kSaveFPRegs);

  }

  // Convenience function: Same as above, but takes the fid instead.

  void CallRuntime(Runtime::FunctionId id, int num_arguments) {

    CallRuntime(Runtime::FunctionForId(id), num_arguments);

  }

  // Convenience function: call an external reference.

  void CallExternalReference(const ExternalReference& ext,

                             int num_arguments);

  // Tail call of a runtime routine (jump).

  // Like JumpToExternalReference, but also takes care of passing the number

  // of parameters.

  void TailCallExternalReference(const ExternalReference& ext,

                                 int num_arguments,

                                 int result_size);

  // Convenience function: tail call a runtime routine (jump).

  void TailCallRuntime(Runtime::FunctionId fid,

                       int num_arguments,

                       int result_size);

  // Jump to a runtime routine.

  void JumpToExternalReference(const ExternalReference& ext, int result_size);

  // Prepares stack to put arguments (aligns and so on).  WIN64 calling

  // convention requires to put the pointer to the return value slot into

  // rcx (rcx must be preserverd until CallApiFunctionAndReturn).  Saves

  // context (rsi).  Clobbers rax.  Allocates arg_stack_space * kPointerSize

  // inside the exit frame (not GCed) accessible via StackSpaceOperand.

  void PrepareCallApiFunction(int arg_stack_space);

  // Calls an API function.  Allocates HandleScope, extracts returned value

  // from handle and propagates exceptions.  Clobbers r14, r15, rbx and

  // caller-save registers.  Restores context.  On return removes

  // stack_space * kPointerSize (GCed).

  void CallApiFunctionAndReturn(Address function_address,

                                Address thunk_address,

                                Register thunk_last_arg,

                                int stack_space,

                                Operand return_value_operand,

                                Operand* context_restore_operand);

  // Before calling a C-function from generated code, align arguments on stack.

  // After aligning the frame, arguments must be stored in rsp[0], rsp[8],

  // etc., not pushed. The argument count assumes all arguments are word sized.

  // The number of slots reserved for arguments depends on platform. On Windows

  // stack slots are reserved for the arguments passed in registers. On other

  // platforms stack slots are only reserved for the arguments actually passed

  // on the stack.

  void PrepareCallCFunction(int num_arguments);

  // Calls a C function and cleans up the space for arguments allocated

  // by PrepareCallCFunction. The called function is not allowed to trigger a

  // garbage collection, since that might move the code and invalidate the

  // return address (unless this is somehow accounted for by the called

  // function).

  void CallCFunction(ExternalReference function, int num_arguments);

  void CallCFunction(Register function, int num_arguments);

  // Calculate the number of stack slots to reserve for arguments when calling a

  // C function.

  int ArgumentStackSlotsForCFunctionCall(int num_arguments);

  // ---------------------------------------------------------------------------

  // Utilities

  void Ret();

  // Return and drop arguments from stack, where the number of arguments

  // may be bigger than 2^16 - 1.  Requires a scratch register.

  void Ret(int bytes_dropped, Register scratch);

  Handle<Object> CodeObject() {

    ASSERT(!code_object_.is_null());

    return code_object_;

  }

  // Copy length bytes from source to destination.

  // Uses scratch register internally (if you have a low-eight register

  // free, do use it, otherwise kScratchRegister will be used).

  // The min_length is a minimum limit on the value that length will have.

  // The algorithm has some special cases that might be omitted if the string

  // is known to always be long.

  void CopyBytes(Register destination,

                 Register source,

                 Register length,

                 int min_length = 0,

                 Register scratch = kScratchRegister);

  // Initialize fields with filler values.  Fields starting at |start_offset|

  // not including end_offset are overwritten with the value in |filler|.  At

  // the end the loop, |start_offset| takes the value of |end_offset|.

  void InitializeFieldsWithFiller(Register start_offset,

                                  Register end_offset,

                                  Register filler);

  // ---------------------------------------------------------------------------

  // 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, BailoutReason reason);

  void AssertFastElements(Register elements);

  // Like Assert(), but always enabled.

  void Check(Condition cc, BailoutReason reason);

  // Print a message to stdout and abort execution.

  void Abort(BailoutReason msg);

  // Check that the stack is aligned.

  void CheckStackAlignment();

  // 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_; }

  void set_has_frame(bool value) { has_frame_ = value; }

  bool has_frame() { return has_frame_; }

  inline bool AllowThisStubCall(CodeStub* stub);

  static int SafepointRegisterStackIndex(Register reg) {

    return SafepointRegisterStackIndex(reg.code());

  }

  // Activation support.

  void EnterFrame(StackFrame::Type type);

  void LeaveFrame(StackFrame::Type type);

  // Expects object in rax and returns map with validated enum cache

  // in rax.  Assumes that any other register can be used as a scratch.

  void CheckEnumCache(Register null_value,

                      Label* call_runtime);

  // AllocationMemento support. Arrays may have an associated

  // AllocationMemento object that can be checked for in order to pretransition

  // to another type.

  // On entry, receiver_reg should point to the array object.

  // scratch_reg gets clobbered.

  // If allocation info is present, condition flags are set to equal.

  void TestJSArrayForAllocationMemento(Register receiver_reg,

                                       Register scratch_reg,

                                       Label* no_memento_found);