macro-assembler-x64.h

// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef INCLUDED_FROM_MACRO_ASSEMBLER_H
#error This header must be included via macro-assembler.h
#endif

#ifndef V8_X64_MACRO_ASSEMBLER_X64_H_
#define V8_X64_MACRO_ASSEMBLER_X64_H_

#include "src/bailout-reason.h"
#include "src/base/flags.h"
#include "src/contexts.h"
#include "src/globals.h"
#include "src/x64/assembler-x64.h"

namespace v8 {
namespace internal {

// Give alias names to registers for calling conventions.
constexpr Register kReturnRegister0 = rax;
constexpr Register kReturnRegister1 = rdx;
constexpr Register kReturnRegister2 = r8;
constexpr Register kJSFunctionRegister = rdi;
constexpr Register kContextRegister = rsi;
constexpr Register kAllocateSizeRegister = rdx;
constexpr Register kSpeculationPoisonRegister = r12;
constexpr Register kInterpreterAccumulatorRegister = rax;
constexpr Register kInterpreterBytecodeOffsetRegister = r9;
constexpr Register kInterpreterBytecodeArrayRegister = r14;
constexpr Register kInterpreterDispatchTableRegister = r15;

constexpr Register kJavaScriptCallArgCountRegister = rax;
constexpr Register kJavaScriptCallCodeStartRegister = rcx;
constexpr Register kJavaScriptCallTargetRegister = kJSFunctionRegister;
constexpr Register kJavaScriptCallNewTargetRegister = rdx;
constexpr Register kJavaScriptCallExtraArg1Register = rbx;

constexpr Register kRuntimeCallFunctionRegister = rbx;
constexpr Register kRuntimeCallArgCountRegister = rax;
constexpr Register kRuntimeCallArgvRegister = r15;
constexpr Register kWasmInstanceRegister = rsi;

// 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.
constexpr Register kScratchRegister = r10;
constexpr XMMRegister kScratchDoubleReg = xmm15;
constexpr Register kRootRegister = r13;  // callee save

constexpr Register kOffHeapTrampolineRegister = kScratchRegister;

// Convenience for platform-independent signatures.
typedef Operand MemOperand;

class StringConstantBase;

enum RememberedSetAction { EMIT_REMEMBERED_SET, OMIT_REMEMBERED_SET };
enum SmiCheck { INLINE_SMI_CHECK, OMIT_SMI_CHECK };

struct SmiIndex {
  SmiIndex(Register index_register, ScaleFactor scale)
      : reg(index_register),
        scale(scale) {}
  Register reg;
  ScaleFactor scale;
};

enum StackArgumentsAccessorReceiverMode {
  ARGUMENTS_CONTAIN_RECEIVER,
  ARGUMENTS_DONT_CONTAIN_RECEIVER
};

class StackArgumentsAccessor {
 public:
  StackArgumentsAccessor(Register base_reg, int argument_count_immediate,
                         StackArgumentsAccessorReceiverMode receiver_mode =
                             ARGUMENTS_CONTAIN_RECEIVER,
                         int extra_displacement_to_last_argument = 0)
      : base_reg_(base_reg),
        argument_count_reg_(no_reg),
        argument_count_immediate_(argument_count_immediate),
        receiver_mode_(receiver_mode),
        extra_displacement_to_last_argument_(
            extra_displacement_to_last_argument) {}

  StackArgumentsAccessor(Register base_reg, Register argument_count_reg,
                         StackArgumentsAccessorReceiverMode receiver_mode =
                             ARGUMENTS_CONTAIN_RECEIVER,
                         int extra_displacement_to_last_argument = 0)
      : base_reg_(base_reg),
        argument_count_reg_(argument_count_reg),
        argument_count_immediate_(0),
        receiver_mode_(receiver_mode),
        extra_displacement_to_last_argument_(
            extra_displacement_to_last_argument) {}

  StackArgumentsAccessor(Register base_reg,
                         const ParameterCount& parameter_count,
                         StackArgumentsAccessorReceiverMode receiver_mode =
                             ARGUMENTS_CONTAIN_RECEIVER,
                         int extra_displacement_to_last_argument = 0);

  Operand GetArgumentOperand(int index);
  Operand GetReceiverOperand() {
    DCHECK(receiver_mode_ == ARGUMENTS_CONTAIN_RECEIVER);
    return GetArgumentOperand(0);
  }

 private:
  const Register base_reg_;
  const Register argument_count_reg_;
  const int argument_count_immediate_;
  const StackArgumentsAccessorReceiverMode receiver_mode_;
  const int extra_displacement_to_last_argument_;

  DISALLOW_IMPLICIT_CONSTRUCTORS(StackArgumentsAccessor);
};

class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 public:
  TurboAssembler(const AssemblerOptions& options, void* buffer, int buffer_size)
      : TurboAssemblerBase(options, buffer, buffer_size) {}

  TurboAssembler(Isolate* isolate, const AssemblerOptions& options,
                 void* buffer, int buffer_size,
                 CodeObjectRequired create_code_object)
      : TurboAssemblerBase(isolate, options, buffer, buffer_size,
                           create_code_object) {}

  template <typename Dst, typename... Args>
  struct AvxHelper {
    Assembler* assm;
    // Call an method where the AVX version expects the dst argument to be
    // duplicated.
    template <void (Assembler::*avx)(Dst, Dst, Args...),
              void (Assembler::*no_avx)(Dst, Args...)>
    void emit(Dst dst, Args... args) {
      if (CpuFeatures::IsSupported(AVX)) {
        CpuFeatureScope scope(assm, AVX);
        (assm->*avx)(dst, dst, args...);
      } else {
        (assm->*no_avx)(dst, args...);
      }
    }

    // Call an method where the AVX version expects no duplicated dst argument.
    template <void (Assembler::*avx)(Dst, Args...),
              void (Assembler::*no_avx)(Dst, Args...)>
    void emit(Dst dst, Args... args) {
      if (CpuFeatures::IsSupported(AVX)) {
        CpuFeatureScope scope(assm, AVX);
        (assm->*avx)(dst, args...);
      } else {
        (assm->*no_avx)(dst, args...);
      }
    }
  };

#define AVX_OP(macro_name, name)                                             \
  template <typename Dst, typename... Args>                                  \
  void macro_name(Dst dst, Args... args) {                                   \
    AvxHelper<Dst, Args...>{this}                                            \
        .template emit<&Assembler::v##name, &Assembler::name>(dst, args...); \
  }

  AVX_OP(Subsd, subsd)
  AVX_OP(Divss, divss)
  AVX_OP(Divsd, divsd)
  AVX_OP(Xorps, xorps)
  AVX_OP(Xorpd, xorpd)
  AVX_OP(Movd, movd)
  AVX_OP(Movq, movq)
  AVX_OP(Movaps, movaps)
  AVX_OP(Movapd, movapd)
  AVX_OP(Movups, movups)
  AVX_OP(Movmskps, movmskps)
  AVX_OP(Movmskpd, movmskpd)
  AVX_OP(Movss, movss)
  AVX_OP(Movsd, movsd)
  AVX_OP(Pcmpeqd, pcmpeqd)
  AVX_OP(Pslld, pslld)
  AVX_OP(Psllq, psllq)
  AVX_OP(Psrld, psrld)
  AVX_OP(Psrlq, psrlq)
  AVX_OP(Addsd, addsd)
  AVX_OP(Mulsd, mulsd)
  AVX_OP(Andps, andps)
  AVX_OP(Andpd, andpd)
  AVX_OP(Orpd, orpd)
  AVX_OP(Cmpeqps, cmpeqps)
  AVX_OP(Cmpltps, cmpltps)
  AVX_OP(Cmpleps, cmpleps)
  AVX_OP(Cmpneqps, cmpneqps)
  AVX_OP(Cmpnltps, cmpnltps)
  AVX_OP(Cmpnleps, cmpnleps)
  AVX_OP(Cmpeqpd, cmpeqpd)
  AVX_OP(Cmpltpd, cmpltpd)
  AVX_OP(Cmplepd, cmplepd)
  AVX_OP(Cmpneqpd, cmpneqpd)
  AVX_OP(Cmpnltpd, cmpnltpd)
  AVX_OP(Cmpnlepd, cmpnlepd)
  AVX_OP(Roundss, roundss)
  AVX_OP(Roundsd, roundsd)
  AVX_OP(Sqrtss, sqrtss)
  AVX_OP(Sqrtsd, sqrtsd)
  AVX_OP(Ucomiss, ucomiss)
  AVX_OP(Ucomisd, ucomisd)

#undef AVX_OP

  void PushReturnAddressFrom(Register src) { pushq(src); }
  void PopReturnAddressTo(Register dst) { popq(dst); }

  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);

  // Load a register with a long value as efficiently as possible.
  void Set(Register dst, int64_t x);
  void Set(Operand dst, intptr_t x);

  // Operations on roots in the root-array.
  void LoadRoot(Register destination, RootIndex index) override;
  void LoadRoot(Operand destination, RootIndex index) {
    LoadRoot(kScratchRegister, index);
    movp(destination, kScratchRegister);
  }

  void Push(Register src);
  void Push(Operand src);
  void Push(Immediate value);
  void Push(Smi smi);
  void Push(Handle<HeapObject> source);

  // 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);

  void CheckPageFlag(Register object, Register scratch, int mask, Condition cc,
                     Label* condition_met,
                     Label::Distance condition_met_distance = Label::kFar);

  void Cvtss2sd(XMMRegister dst, XMMRegister src);
  void Cvtss2sd(XMMRegister dst, Operand src);
  void Cvtsd2ss(XMMRegister dst, XMMRegister src);
  void Cvtsd2ss(XMMRegister dst, Operand src);
  void Cvttsd2si(Register dst, XMMRegister src);
  void Cvttsd2si(Register dst, Operand src);
  void Cvttsd2siq(Register dst, XMMRegister src);
  void Cvttsd2siq(Register dst, Operand src);
  void Cvttss2si(Register dst, XMMRegister src);
  void Cvttss2si(Register dst, Operand src);
  void Cvttss2siq(Register dst, XMMRegister src);
  void Cvttss2siq(Register dst, Operand src);
  void Cvtqsi2ss(XMMRegister dst, Register src);
  void Cvtqsi2ss(XMMRegister dst, Operand src);
  void Cvtqsi2sd(XMMRegister dst, Register src);
  void Cvtqsi2sd(XMMRegister dst, Operand src);
  void Cvtlsi2ss(XMMRegister dst, Register src);
  void Cvtlsi2ss(XMMRegister dst, Operand src);
  void Cvtlui2ss(XMMRegister dst, Register src);
  void Cvtlui2ss(XMMRegister dst, Operand src);
  void Cvtlui2sd(XMMRegister dst, Register src);
  void Cvtlui2sd(XMMRegister dst, Operand src);
  void Cvtqui2ss(XMMRegister dst, Register src);
  void Cvtqui2ss(XMMRegister dst, Operand src);
  void Cvtqui2sd(XMMRegister dst, Register src);
  void Cvtqui2sd(XMMRegister dst, Operand src);
  void Cvttsd2uiq(Register dst, Operand src, Label* fail = nullptr);
  void Cvttsd2uiq(Register dst, XMMRegister src, Label* fail = nullptr);
  void Cvttss2uiq(Register dst, Operand src, Label* fail = nullptr);
  void Cvttss2uiq(Register dst, XMMRegister src, Label* fail = nullptr);

  // cvtsi2sd instruction only writes to the low 64-bit of dst register, which
  // hinders register renaming and makes dependence chains longer. So we use
  // xorpd to clear the dst register before cvtsi2sd to solve this issue.
  void Cvtlsi2sd(XMMRegister dst, Register src);
  void Cvtlsi2sd(XMMRegister dst, Operand src);

  void Lzcntq(Register dst, Register src);
  void Lzcntq(Register dst, Operand src);
  void Lzcntl(Register dst, Register src);
  void Lzcntl(Register dst, Operand src);
  void Tzcntq(Register dst, Register src);
  void Tzcntq(Register dst, Operand src);
  void Tzcntl(Register dst, Register src);
  void Tzcntl(Register dst, Operand src);
  void Popcntl(Register dst, Register src);
  void Popcntl(Register dst, Operand src);
  void Popcntq(Register dst, Register src);
  void Popcntq(Register dst, Operand src);

  // Is the value a tagged smi.
  Condition CheckSmi(Register src);
  Condition CheckSmi(Operand src);

  // Jump to label if the value is a tagged smi.
  void JumpIfSmi(Register src, Label* on_smi,
                 Label::Distance near_jump = Label::kFar);

  void JumpIfEqual(Register a, int32_t b, Label* dest) {
    cmpl(a, Immediate(b));
    j(equal, dest);
  }

  void JumpIfLessThan(Register a, int32_t b, Label* dest) {
    cmpl(a, Immediate(b));
    j(less, dest);
  }

  void Move(Register dst, Smi source);

  void Move(Operand dst, Smi source) {
    Register constant = GetSmiConstant(source);
    movp(dst, constant);
  }

  void Move(Register dst, ExternalReference ext);

  void Move(XMMRegister dst, uint32_t src);
  void Move(XMMRegister dst, uint64_t src);
  void Move(XMMRegister dst, float src) { Move(dst, bit_cast<uint32_t>(src)); }
  void Move(XMMRegister dst, double src) { Move(dst, bit_cast<uint64_t>(src)); }

  // Move if the registers are not identical.
  void Move(Register target, Register source);

  void Move(Register dst, Handle<HeapObject> source,
            RelocInfo::Mode rmode = RelocInfo::EMBEDDED_OBJECT);
  void Move(Operand dst, Handle<HeapObject> source,
            RelocInfo::Mode rmode = RelocInfo::EMBEDDED_OBJECT);

  // Loads a pointer into a register with a relocation mode.
  void Move(Register dst, Address ptr, RelocInfo::Mode rmode) {
    // This method must not be used with heap object references. The stored
    // address is not GC safe. Use the handle version instead.
    DCHECK(rmode > RelocInfo::LAST_GCED_ENUM);
    movp(dst, ptr, rmode);
  }

  void MoveStringConstant(Register result, const StringConstantBase* string,
                          RelocInfo::Mode rmode = RelocInfo::EMBEDDED_OBJECT);

  // Convert smi to word-size sign-extended value.
  void SmiUntag(Register dst, Register src);
  void SmiUntag(Register dst, Operand src);

  // Loads the address of the external reference into the destination
  // register.
  void LoadAddress(Register destination, ExternalReference source);

  void LoadFromConstantsTable(Register destination,
                              int constant_index) override;
  void LoadRootRegisterOffset(Register destination, intptr_t offset) override;
  void LoadRootRelative(Register destination, int32_t offset) override;

  // 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 ExternalReferenceAsOperand(ExternalReference reference,
                                     Register scratch = kScratchRegister);

  void Call(Register reg) { call(reg); }
  void Call(Operand op);
  void Call(Handle<Code> code_object, RelocInfo::Mode rmode);
  void Call(Address destination, RelocInfo::Mode rmode);
  void Call(ExternalReference ext);
  void Call(Label* target) { call(target); }

  void RetpolineCall(Register reg);
  void RetpolineCall(Address destination, RelocInfo::Mode rmode);

  void Jump(Address destination, RelocInfo::Mode rmode);
  void Jump(ExternalReference ext);
  void Jump(Operand op);
  void Jump(Handle<Code> code_object, RelocInfo::Mode rmode,
            Condition cc = always);

  void RetpolineJump(Register reg);

  void CallForDeoptimization(Address target, int deopt_id,
                             RelocInfo::Mode rmode) {
    USE(deopt_id);
    call(target, rmode);
  }

  // Non-SSE2 instructions.
  void Pextrd(Register dst, XMMRegister src, int8_t imm8);
  void Pinsrd(XMMRegister dst, Register src, int8_t imm8);
  void Pinsrd(XMMRegister dst, Operand src, int8_t imm8);

  void CompareRoot(Register with, RootIndex index);
  void CompareRoot(Operand with, RootIndex index);

  // Generates function and stub prologue code.
  void StubPrologue(StackFrame::Type type);
  void Prologue();

  // Calls Abort(msg) if the condition cc is not satisfied.
  // Use --debug_code to enable.
  void Assert(Condition cc, AbortReason reason);

  // Like Assert(), but without condition.
  // Use --debug_code to enable.
  void AssertUnreachable(AbortReason reason);

  // 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);

  // Like Assert(), but always enabled.
  void Check(Condition cc, AbortReason reason);

  // Print a message to stdout and abort execution.
  void Abort(AbortReason msg);

  // Check that the stack is aligned.
  void CheckStackAlignment();

  // Activation support.
  void EnterFrame(StackFrame::Type type);
  void EnterFrame(StackFrame::Type type, bool load_constant_pool_pointer_reg) {
    // Out-of-line constant pool not implemented on x64.
    UNREACHABLE();
  }
  void LeaveFrame(StackFrame::Type type);

  // Removes current frame and its arguments from the stack preserving the
  // arguments and a return address pushed to the stack for the next call.  Both
  // |callee_args_count| and |caller_args_count_reg| do not include receiver.
  // |callee_args_count| is not modified, |caller_args_count_reg| is trashed.
  void PrepareForTailCall(const ParameterCount& callee_args_count,
                          Register caller_args_count_reg, Register scratch0,
                          Register scratch1);

  inline bool AllowThisStubCall(CodeStub* stub);

  // Call a runtime routine. This expects {centry} to contain a fitting CEntry
  // builtin for the target runtime function and uses an indirect call.
  void CallRuntimeWithCEntry(Runtime::FunctionId fid, Register centry);

  void InitializeRootRegister() {
    ExternalReference isolate_root = ExternalReference::isolate_root(isolate());
    Move(kRootRegister, isolate_root);
  }

  void SaveRegisters(RegList registers);
  void RestoreRegisters(RegList registers);

  void CallRecordWriteStub(Register object, Register address,
                           RememberedSetAction remembered_set_action,
                           SaveFPRegsMode fp_mode);
  void CallRecordWriteStub(Register object, Register address,
                           RememberedSetAction remembered_set_action,
                           SaveFPRegsMode fp_mode, Address wasm_target);

  void MoveNumber(Register dst, double value);
  void MoveNonSmi(Register dst, double value);

  // Calculate how much stack space (in bytes) are required to store caller
  // registers excluding those specified in the arguments.
  int RequiredStackSizeForCallerSaved(SaveFPRegsMode fp_mode,
                                      Register exclusion1 = no_reg,
                                      Register exclusion2 = no_reg,
                                      Register exclusion3 = no_reg) const;

  // PushCallerSaved and PopCallerSaved 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.

  // Push caller saved registers on the stack, and return the number of bytes
  // stack pointer is adjusted.
  int PushCallerSaved(SaveFPRegsMode fp_mode, Register exclusion1 = no_reg,
                      Register exclusion2 = no_reg,
                      Register exclusion3 = no_reg);
  // Restore caller saved registers from the stack, and return the number of
  // bytes stack pointer is adjusted.
  int PopCallerSaved(SaveFPRegsMode fp_mode, Register exclusion1 = no_reg,
                     Register exclusion2 = no_reg,
                     Register exclusion3 = no_reg);

  // Compute the start of the generated instruction stream from the current PC.
  // This is an alternative to embedding the {CodeObject} handle as a reference.
  void ComputeCodeStartAddress(Register dst);

  void ResetSpeculationPoisonRegister();

  // ---------------------------------------------------------------------------
  // Pointer compresstion Support

  // TODO(ishell): remove |scratch_for_debug| once pointer compression works.
  void DecompressTaggedSigned(Register destination, Operand field_operand,
                              Register scratch_for_debug);
  void DecompressTaggedPointer(Register destination, Operand field_operand,
                               Register scratch_for_debug);
  void DecompressAnyTagged(Register destination, Operand field_operand,
                           Register scratch, Register scratch_for_debug);

 protected:
  static const int kSmiShift = kSmiTagSize + kSmiShiftSize;
  int smi_count = 0;
  int heap_object_count = 0;

  // Returns a register holding the smi value. The register MUST NOT be
  // modified. It may be the "smi 1 constant" register.
  Register GetSmiConstant(Smi value);

  void CallRecordWriteStub(Register object, Register address,
                           RememberedSetAction remembered_set_action,
                           SaveFPRegsMode fp_mode, Handle<Code> code_target,
                           Address wasm_target);
};

// MacroAssembler implements a collection of frequently used macros.
class MacroAssembler : public TurboAssembler {
 public:
  MacroAssembler(const AssemblerOptions& options, void* buffer, int size)
      : TurboAssembler(options, buffer, size) {}

  MacroAssembler(Isolate* isolate, void* buffer, int size,
                 CodeObjectRequired create_code_object)
      : MacroAssembler(isolate, AssemblerOptions::Default(isolate), buffer,
                       size, create_code_object) {}

  MacroAssembler(Isolate* isolate, const AssemblerOptions& options,
                 void* buffer, int size, CodeObjectRequired create_code_object);

  // 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 = ExternalReferenceAsOperand(extref);
  //   operation(operand, ..);
  void Load(Register destination, ExternalReference source);
  void Store(ExternalReference destination, Register source);

  // Pushes the address of the external reference onto the stack.
  void PushAddress(ExternalReference source);

  // Operations on roots in the root-array.
  // 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 PushRoot(RootIndex index);

  // Compare the object in a register to a value and jump if they are equal.
  void JumpIfRoot(Register with, RootIndex index, Label* if_equal,
                  Label::Distance if_equal_distance = Label::kFar) {
    CompareRoot(with, index);
    j(equal, if_equal, if_equal_distance);
  }
  void JumpIfRoot(Operand with, RootIndex index, Label* if_equal,
                  Label::Distance if_equal_distance = Label::kFar) {
    CompareRoot(with, index);
    j(equal, if_equal, if_equal_distance);
  }

  // Compare the object in a register to a value and jump if they are not equal.
  void JumpIfNotRoot(Register with, RootIndex index, Label* if_not_equal,
                     Label::Distance if_not_equal_distance = Label::kFar) {
    CompareRoot(with, index);
    j(not_equal, if_not_equal, if_not_equal_distance);
  }
  void JumpIfNotRoot(Operand with, RootIndex index, Label* if_not_equal,
                     Label::Distance if_not_equal_distance = Label::kFar) {
    CompareRoot(with, index);
    j(not_equal, if_not_equal, if_not_equal_distance);
  }

  // ---------------------------------------------------------------------------
  // GC Support

  // 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);

  // 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);

  // Frame restart support.
  void MaybeDropFrames();

  // 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,
                      StackFrame::Type frame_type = StackFrame::EXIT);

  // 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 (if pop_arguments == true).
  void LeaveExitFrame(bool save_doubles = false, bool pop_arguments = true);

  // Leave the current exit frame. Expects/provides the return value in
  // register rax (untouched).
  void LeaveApiExitFrame();

  // Push and pop the registers that can hold pointers.
  void PushSafepointRegisters() { Pushad(); }
  void PopSafepointRegisters() { Popad(); }

  // ---------------------------------------------------------------------------
  // JavaScript invokes

  // Invoke the JavaScript function code by either calling or jumping.
  void InvokeFunctionCode(Register function, Register new_target,
                          const ParameterCount& expected,
                          const ParameterCount& actual, InvokeFlag flag);

  // On function call, call into the debugger if necessary.
  void CheckDebugHook(Register fun, Register new_target,
                      const ParameterCount& expected,
                      const ParameterCount& actual);

  // Invoke the JavaScript function in the given register. Changes the
  // current context to the context in the function before invoking.
  void InvokeFunction(Register function, Register new_target,
                      const ParameterCount& actual, InvokeFlag flag);

  void InvokeFunction(Register function, Register new_target,
                      const ParameterCount& expected,
                      const ParameterCount& actual, InvokeFlag flag);

  // ---------------------------------------------------------------------------
  // Conversions between tagged smi values and non-tagged integer values.

  // Tag an word-size value. The result must be known to be a valid smi value.
  void SmiTag(Register dst, Register src);

  // 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, Operand src);
  void SmiCompare(Operand dst, Register src);
  void SmiCompare(Operand dst, Smi src);

  // Functions performing a check on a known or potential smi. Returns
  // a condition that is satisfied if the check is successful.

  // Test-and-jump functions. Typically combines a check function
  // above with a conditional jump.

  // 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 tagged smi.
  void JumpIfNotSmi(Operand src, Label* on_not_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(Operand dst, Smi constant);

  // Specialized operations

  // 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);

  // ---------------------------------------------------------------------------
  // Macro instructions.

  // Load/store with specific representation.
  void Load(Register dst, Operand src, Representation r);
  void Store(Operand dst, Register src, Representation r);

  void Cmp(Register dst, Handle<Object> source);
  void Cmp(Operand dst, Handle<Object> source);
  void Cmp(Register dst, Smi src);
  void Cmp(Operand dst, Smi src);

  // 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);
  // Emit code to discard a positive number of pointer-sized elements
  // from the stack under the return address which remains on the top,
  // clobbering the rsp register.
  void DropUnderReturnAddress(int stack_elements,
                              Register scratch = kScratchRegister);

  void PushQuad(Operand src);
  void PushImm32(int32_t imm32);
  void Pop(Register dst);
  void Pop(Operand dst);
  void PopQuad(Operand dst);

  // ---------------------------------------------------------------------------
  // SIMD macros.
  void Absps(XMMRegister dst);
  void Negps(XMMRegister dst);
  void Abspd(XMMRegister dst);
  void Negpd(XMMRegister dst);
  // Generates a trampoline to jump to the off-heap instruction stream.
  void JumpToInstructionStream(Address entry);

  // Non-x64 instructions.
  // Push/pop all general purpose registers.
  // Does not push rsp/rbp nor any of the assembler's special purpose registers
  // (kScratchRegister, kRootRegister).
  void Pushad();
  void Popad();

  // 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);

  void DoubleToI(Register result_reg, XMMRegister input_reg,
                 XMMRegister scratch, Label* lost_precision, Label* is_nan,
                 Label::Distance dst = Label::kFar);

  template<typename Field>
  void DecodeField(Register reg) {
    static const int shift = Field::kShift;
    static const int mask = Field::kMask >> Field::kShift;
    if (shift != 0) {
      shrp(reg, Immediate(shift));
    }
    andp(reg, Immediate(mask));
  }

  // 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(Operand object);

  // Abort execution if argument is not a Constructor, enabled via --debug-code.
  void AssertConstructor(Register object);

  // Abort execution if argument is not a JSFunction, enabled via --debug-code.
  void AssertFunction(Register object);

  // Abort execution if argument is not a JSBoundFunction,
  // enabled via --debug-code.
  void AssertBoundFunction(Register object);

  // Abort execution if argument is not a JSGeneratorObject (or subclass),
  // enabled via --debug-code.
  void AssertGeneratorObject(Register object);

  // Abort execution if argument is not undefined or an AllocationSite, enabled
  // via --debug-code.
  void AssertUndefinedOrAllocationSite(Register object);

  // ---------------------------------------------------------------------------
  // Exception handling

  // Push a new stack handler and link it into stack handler chain.
  void PushStackHandler();

  // Unlink the stack handler on top of the stack from the stack handler chain.
  void PopStackHandler();

  // ---------------------------------------------------------------------------
  // Support functions.

  // Load the global proxy from the current context.
  void LoadGlobalProxy(Register dst) {
    LoadNativeContextSlot(Context::GLOBAL_PROXY_INDEX, dst);
  }

  // Load the native context slot with the current index.
  void LoadNativeContextSlot(int index, Register dst);

  // ---------------------------------------------------------------------------
  // Runtime calls

  // Call a code stub.
  // The code object is generated immediately, in contrast to
  // TurboAssembler::CallStubDelayed.
  void CallStub(CodeStub* stub);

  // Tail call a code stub (jump).
  void TailCallStub(CodeStub* stub);

  // Call a runtime routine.
  void CallRuntime(const Runtime::Function* f,
                   int num_arguments,
                   SaveFPRegsMode save_doubles = kDontSaveFPRegs);

  // Convenience function: Same as above, but takes the fid instead.
  void CallRuntime(Runtime::FunctionId fid,
                   SaveFPRegsMode save_doubles = kDontSaveFPRegs) {
    const Runtime::Function* function = Runtime::FunctionForId(fid);
    CallRuntime(function, function->nargs, save_doubles);
  }

  // Convenience function: Same as above, but takes the fid instead.
  void CallRuntime(Runtime::FunctionId fid, int num_arguments,
                   SaveFPRegsMode save_doubles = kDontSaveFPRegs) {
    CallRuntime(Runtime::FunctionForId(fid), num_arguments, save_doubles);
  }

  // Convenience function: tail call a runtime routine (jump)
  void TailCallRuntime(Runtime::FunctionId fid);

  // Jump to a runtime routines
  void JumpToExternalReference(const ExternalReference& ext,
                               bool builtin_exit_frame = false);

  // ---------------------------------------------------------------------------
  // StatsCounter support
  void IncrementCounter(StatsCounter* counter, int value);
  void DecrementCounter(StatsCounter* counter, int value);

  // ---------------------------------------------------------------------------
  // In-place weak references.
  void LoadWeakValue(Register in_out, Label* target_if_cleared);

  // ---------------------------------------------------------------------------
  // Debugging

  static int SafepointRegisterStackIndex(Register reg) {
    return SafepointRegisterStackIndex(reg.code());
  }

 private:
  // Order general registers are pushed by Pushad.
  // rax, rcx, rdx, rbx, rsi, rdi, r8, r9, r11, r12, r14, r15.
  static const int kSafepointPushRegisterIndices[Register::kNumRegisters];
  static const int kNumSafepointSavedRegisters = 12;

  // Helper functions for generating invokes.
  void InvokePrologue(const ParameterCount& expected,
                      const ParameterCount& actual, Label* done,
                      bool* definitely_mismatches, InvokeFlag flag,
                      Label::Distance near_jump);

  void EnterExitFramePrologue(bool save_rax, StackFrame::Type frame_type);

  // Allocates arg_stack_space * kPointerSize memory (not GCed) on the stack
  // accessible via StackSpaceOperand.
  void EnterExitFrameEpilogue(int arg_stack_space, bool save_doubles);

  void LeaveExitFrameEpilogue();

  // Helper for implementing JumpIfNotInNewSpace and JumpIfInNewSpace.
  void InNewSpace(Register object,
                  Register scratch,
                  Condition cc,
                  Label* branch,
                  Label::Distance distance = Label::kFar);

  // Compute memory operands for safepoint stack slots.
  static int SafepointRegisterStackIndex(int reg_code) {
    return kNumSafepointRegisters - kSafepointPushRegisterIndices[reg_code] - 1;
  }

  // Needs access to SafepointRegisterStackIndex for compiled frame
  // traversal.
  friend class StandardFrame;
};

// -----------------------------------------------------------------------------
// Static helper functions.

// Generate an Operand for loading a field from an object.
inline Operand FieldOperand(Register object, int offset) {
  return Operand(object, offset - kHeapObjectTag);
}


// Generate an Operand for loading an indexed field from an object.
inline Operand FieldOperand(Register object,
                            Register index,
                            ScaleFactor scale,
                            int offset) {
  return Operand(object, index, scale, offset - kHeapObjectTag);
}


inline Operand ContextOperand(Register context, int index) {
  return Operand(context, Context::SlotOffset(index));
}


inline Operand ContextOperand(Register context, Register index) {
  return Operand(context, index, times_pointer_size, Context::SlotOffset(0));
}


inline Operand NativeContextOperand() {
  return ContextOperand(rsi, Context::NATIVE_CONTEXT_INDEX);
}


// Provides access to exit frame stack space (not GCed).
inline Operand StackSpaceOperand(int index) {
#ifdef _WIN64
  const int kShaddowSpace = 4;
  return Operand(rsp, (index + kShaddowSpace) * kPointerSize);
#else
  return Operand(rsp, index * kPointerSize);
#endif
}


inline Operand StackOperandForReturnAddress(int32_t disp) {
  return Operand(rsp, disp);
}

#define ACCESS_MASM(masm) masm->

}  // namespace internal
}  // namespace v8

#endif  // V8_X64_MACRO_ASSEMBLER_X64_H_