macro-assembler-ia32.h

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// 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 V8_IA32_MACRO_ASSEMBLER_IA32_H_
#define V8_IA32_MACRO_ASSEMBLER_IA32_H_
 
#include "src/assembler.h"
#include "src/bailout-reason.h"
#include "src/frames.h"
#include "src/globals.h"
 
namespace v8 {
namespace internal {
 
// Convenience for platform-independent signatures.  We do not normally
// distinguish memory operands from other operands on ia32.
typedef Operand MemOperand;
 
enum RememberedSetAction { EMIT_REMEMBERED_SET, OMIT_REMEMBERED_SET };
enum SmiCheck { INLINE_SMI_CHECK, OMIT_SMI_CHECK };
enum PointersToHereCheck {
  kPointersToHereMaybeInteresting,
  kPointersToHereAreAlwaysInteresting
};
 
 
enum RegisterValueType {
  REGISTER_VALUE_IS_SMI,
  REGISTER_VALUE_IS_INT32
};
 
 
#ifdef DEBUG
bool AreAliased(Register reg1,
                Register reg2,
                Register reg3 = no_reg,
                Register reg4 = no_reg,
                Register reg5 = no_reg,
                Register reg6 = no_reg,
                Register reg7 = no_reg,
                Register reg8 = no_reg);
#endif
 
 
// 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);
 
  void Load(Register dst, const Operand& src, Representation r);
  void Store(Register src, const Operand& dst, Representation r);
 
  // Operations on roots in the root-array.
  void LoadRoot(Register destination, Heap::RootListIndex index);
  void StoreRoot(Register source, Register scratch, Heap::RootListIndex index);
  void CompareRoot(Register with, Register scratch, Heap::RootListIndex index);
  // These methods can only be used with constant roots (i.e. non-writable
  // and not in new space).
  void CompareRoot(Register with, Heap::RootListIndex index);
  void CompareRoot(const Operand& with, Heap::RootListIndex index);
 
  // ---------------------------------------------------------------------------
  // 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 CheckPageFlagForMap(
      Handle<Map> map,
      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, zero, 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, not_zero, branch, distance);
  }
 
  // Check if an object has a given incremental marking color.  Also uses ecx!
  void HasColor(Register object,
                Register scratch0,
                Register scratch1,
                Label* has_color,
                Label::Distance has_color_distance,
                int first_bit,
                int second_bit);
 
  void JumpIfBlack(Register object,
                   Register scratch0,
                   Register scratch1,
                   Label* on_black,
                   Label::Distance on_black_distance = Label::kFar);
 
  // 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,
      PointersToHereCheck pointers_to_here_check_for_value =
          kPointersToHereMaybeInteresting);
 
  // 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,
      PointersToHereCheck pointers_to_here_check_for_value =
          kPointersToHereMaybeInteresting) {
    RecordWriteField(context,
                     offset + kHeapObjectTag,
                     value,
                     scratch,
                     save_fp,
                     remembered_set_action,
                     smi_check,
                     pointers_to_here_check_for_value);
  }
 
  // 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
  // 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,
      PointersToHereCheck pointers_to_here_check_for_value =
          kPointersToHereMaybeInteresting);
 
  // 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,
      PointersToHereCheck pointers_to_here_check_for_value =
          kPointersToHereMaybeInteresting);
 
  // For page containing |object| mark the region covering the object's map
  // dirty. |object| is the object being stored into, |map| is the Map object
  // that was stored.
  void RecordWriteForMap(
      Register object,
      Handle<Map> map,
      Register scratch1,
      Register scratch2,
      SaveFPRegsMode save_fp);
 
  // ---------------------------------------------------------------------------
  // Debugger Support
 
  void DebugBreak();
 
  // Generates function and stub prologue code.
  void StubPrologue();
  void Prologue(bool code_pre_aging);
 
  // Enter specific kind of exit frame. Expects the number of
  // arguments in register eax and sets up the number of arguments in
  // register edi and the pointer to the first argument in register
  // esi.
  void EnterExitFrame(bool save_doubles);
 
  void EnterApiExitFrame(int argc);
 
  // Leave the current exit frame. Expects the return value in
  // register eax:edx (untouched) and the pointer to the first
  // argument in register esi.
  void LeaveExitFrame(bool save_doubles);
 
  // Leave the current exit frame. Expects the return value in
  // register eax (untouched).
  void LeaveApiExitFrame(bool restore_context);
 
  // 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 global function with the given index.
  void LoadGlobalFunction(int index, 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);
 
  // Push and pop the registers that can hold pointers.
  void PushSafepointRegisters() { pushad(); }
  void PopSafepointRegisters() { popad(); }
  // Store the value in register/immediate src in the safepoint
  // register stack slot for register dst.
  void StoreToSafepointRegisterSlot(Register dst, Register src);
  void StoreToSafepointRegisterSlot(Register dst, Immediate src);
  void LoadFromSafepointRegisterSlot(Register dst, Register src);
 
  void LoadHeapObject(Register result, Handle<HeapObject> object);
  void CmpHeapObject(Register reg, Handle<HeapObject> object);
  void PushHeapObject(Handle<HeapObject> object);
 
  void LoadObject(Register result, Handle<Object> object) {
    AllowDeferredHandleDereference heap_object_check;
    if (object->IsHeapObject()) {
      LoadHeapObject(result, Handle<HeapObject>::cast(object));
    } else {
      Move(result, Immediate(object));
    }
  }
 
  void CmpObject(Register reg, Handle<Object> object) {
    AllowDeferredHandleDereference heap_object_check;
    if (object->IsHeapObject()) {
      CmpHeapObject(reg, Handle<HeapObject>::cast(object));
    } else {
      cmp(reg, Immediate(object));
    }
  }
 
  // ---------------------------------------------------------------------------
  // JavaScript invokes
 
  // 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) {
    InvokeCode(Operand(code), expected, actual, flag, call_wrapper);
  }
 
  void InvokeCode(const Operand& code,
                  const ParameterCount& expected,
                  const ParameterCount& actual,
                  InvokeFlag flag,
                  const CallWrapper& call_wrapper);
 
  // 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);
 
  void InvokeFunction(Register function,
                      const ParameterCount& expected,
                      const ParameterCount& actual,
                      InvokeFlag flag,
                      const CallWrapper& call_wrapper);
 
  void InvokeFunction(Handle<JSFunction> function,
                      const ParameterCount& expected,
                      const ParameterCount& actual,
                      InvokeFlag flag,
                      const CallWrapper& call_wrapper);
 
  // 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);
 
  // Expression support
  // 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 Cvtsi2sd(XMMRegister dst, Register src) { Cvtsi2sd(dst, Operand(src)); }
  void Cvtsi2sd(XMMRegister dst, const Operand& src);
 
  // Support for constant splitting.
  bool IsUnsafeImmediate(const Immediate& x);
  void SafeMove(Register dst, const Immediate& x);
  void SafePush(const Immediate& x);
 
  // Compare object type for heap object.
  // Incoming register is heap_object and outgoing register is map.
  void CmpObjectType(Register heap_object, InstanceType type, Register map);
 
  // Compare instance type for map.
  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 key in
  // the FastDoubleElements array elements, otherwise jump to fail.
  void StoreNumberToDoubleElements(Register maybe_number,
                                   Register elements,
                                   Register key,
                                   Register scratch1,
                                   XMMRegister scratch2,
                                   Label* fail,
                                   int offset = 0);
 
  // Compare an object's map with the specified map.
  void CompareMap(Register obj, Handle<Map> map);
 
  // 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);
 
  // Check if a heap object's type is in the JSObject range, not including
  // JSFunction.  The object's map will be loaded in the map register.
  // Any or all of the three registers may be the same.
  // The contents of the scratch register will always be overwritten.
  void IsObjectJSObjectType(Register heap_object,
                            Register map,
                            Register scratch,
                            Label* fail);
 
  // The contents of the scratch register will be overwritten.
  void IsInstanceJSObjectType(Register map, Register scratch, Label* fail);
 
  // FCmp is 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 scratch_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* lost_precision, Label* is_nan, Label* minus_zero,
                 Label::Distance dst = Label::kFar);
 
  // Smi tagging support.
  void SmiTag(Register reg) {
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiTagSize == 1);
    add(reg, reg);
  }
  void SmiUntag(Register reg) {
    sar(reg, kSmiTagSize);
  }
 
  // Modifies the register even if it does not contain a Smi!
  void SmiUntag(Register reg, Label* is_smi) {
    STATIC_ASSERT(kSmiTagSize == 1);
    sar(reg, kSmiTagSize);
    STATIC_ASSERT(kSmiTag == 0);
    j(not_carry, is_smi);
  }
 
  void LoadUint32(XMMRegister dst, Register src);
 
  // Jump the register contains a smi.
  inline void JumpIfSmi(Register value,
                        Label* smi_label,
                        Label::Distance distance = Label::kFar) {
    test(value, Immediate(kSmiTagMask));
    j(zero, smi_label, distance);
  }
  // Jump if the operand is a smi.
  inline void JumpIfSmi(Operand value,
                        Label* smi_label,
                        Label::Distance distance = Label::kFar) {
    test(value, Immediate(kSmiTagMask));
    j(zero, smi_label, distance);
  }
  // Jump if register contain a non-smi.
  inline void JumpIfNotSmi(Register value,
                           Label* not_smi_label,
                           Label::Distance distance = Label::kFar) {
    test(value, Immediate(kSmiTagMask));
    j(not_zero, not_smi_label, distance);
  }
 
  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;
    static const int mask = Field::kMask >> Field::kShift;
    if (shift != 0) {
      sar(reg, shift);
    }
    and_(reg, Immediate(mask));
  }
 
  template<typename Field>
  void DecodeFieldToSmi(Register reg) {
    static const int shift = Field::kShift;
    static const int mask = (Field::kMask >> Field::kShift) << kSmiTagSize;
    STATIC_ASSERT((mask & (0x80000000u >> (kSmiTagSize - 1))) == 0);
    STATIC_ASSERT(kSmiTag == 0);
    if (shift < kSmiTagSize) {
      shl(reg, kSmiTagSize - shift);
    } else if (shift > kSmiTagSize) {
      sar(reg, shift - kSmiTagSize);
    }
    and_(reg, Immediate(mask));
  }
 
  void LoadPowerOf2(XMMRegister dst, Register scratch, int power);
 
  // Abort execution if argument is not a number, enabled via --debug-code.
  void AssertNumber(Register object);
 
  // Abort execution if argument is not a smi, enabled via --debug-code.
  void AssertSmi(Register object);
 
  // Abort execution if argument is a smi, enabled via --debug-code.
  void AssertNotSmi(Register object);
 
  // 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 undefined or an AllocationSite, enabled
  // via --debug-code.
  void AssertUndefinedOrAllocationSite(Register object);
 
  // ---------------------------------------------------------------------------
  // 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();
 
  // Throw to the top handler in the try hander chain.
  void Throw(Register value);
 
  // Throw past all JS frames to the top JS entry frame.
  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 is clobbered.
  void CheckAccessGlobalProxy(Register holder_reg,
                              Register scratch1,
                              Register scratch2,
                              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,
                RegisterValueType element_count_type,
                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);
 
  // 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. The
  // register scratch2 can be passed as no_reg; the others must be
  // valid registers. Returns tagged pointer in result register, or
  // jumps to gc_required if new space is full.
  void AllocateHeapNumber(Register result,
                          Register scratch1,
                          Register scratch2,
                          Label* gc_required,
                          MutableMode mode = IMMUTABLE);
 
  // 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 AllocateOneByteString(Register result, Register length,
                             Register scratch1, Register scratch2,
                             Register scratch3, Label* gc_required);
  void AllocateOneByteString(Register result, int length, Register scratch1,
                             Register scratch2, 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 AllocateOneByteConsString(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 AllocateOneByteSlicedString(Register result, Register scratch1,
                                   Register scratch2, Label* gc_required);
 
  // Copy memory, byte-by-byte, from source to destination.  Not optimized for
  // long or aligned copies.
  // The contents of index and scratch are destroyed.
  void CopyBytes(Register source,
                 Register destination,
                 Register length,
                 Register scratch);
 
  // 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);
 
  // ---------------------------------------------------------------------------
  // Support functions.
 
  // Check a boolean-bit of a Smi field.
  void BooleanBitTest(Register object, int field_offset, int bit_index);
 
  // Check if result is zero and op is negative.
  void NegativeZeroTest(Register result, Register op, Label* then_label);
 
  // 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 registers may be
  // clobbered.
  void TryGetFunctionPrototype(Register function,
                               Register result,
                               Register scratch,
                               Label* miss,
                               bool miss_on_bound_function = false);
 
  // 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);
 
  // ---------------------------------------------------------------------------
  // Runtime calls
 
  // Call a code stub.  Generate the code if necessary.
  void CallStub(CodeStub* stub, TypeFeedbackId ast_id = TypeFeedbackId::None());
 
  // Tail call a code stub (jump).  Generate the code if necessary.
  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);
  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,
                   SaveFPRegsMode save_doubles = kDontSaveFPRegs) {
    CallRuntime(Runtime::FunctionForId(id), num_arguments, save_doubles);
  }
 
  // Convenience function: call an external reference.
  void CallExternalReference(ExternalReference ref, 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);
 
  // Before calling a C-function from generated code, align arguments on stack.
  // After aligning the frame, arguments must be stored in esp[0], esp[4],
  // etc., not pushed. The argument count assumes all arguments are word sized.
  // Some compilers/platforms require the stack to be aligned when calling
  // C++ code.
  // Needs a scratch register to do some arithmetic. This register will be
  // trashed.
  void PrepareCallCFunction(int num_arguments, Register scratch);
 
  // 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);
 
  // Prepares stack to put arguments (aligns and so on). Reserves
  // space for return value if needed (assumes the return value is a handle).
  // Arguments must be stored in ApiParameterOperand(0), ApiParameterOperand(1)
  // etc. Saves context (esi). If space was reserved for return value then
  // stores the pointer to the reserved slot into esi.
  void PrepareCallApiFunction(int argc);
 
  // Calls an API function.  Allocates HandleScope, extracts returned value
  // from handle and propagates exceptions.  Clobbers ebx, edi and
  // caller-save registers.  Restores context.  On return removes
  // stack_space * kPointerSize (GCed).
  void CallApiFunctionAndReturn(Register function_address,
                                ExternalReference thunk_ref,
                                Operand thunk_last_arg,
                                int stack_space,
                                Operand return_value_operand,
                                Operand* context_restore_operand);
 
  // Jump to a runtime routine.
  void JumpToExternalReference(const ExternalReference& ext);
 
  // ---------------------------------------------------------------------------
  // 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);
 
  // Emit code to discard a non-negative number of pointer-sized elements
  // from the stack, clobbering only the esp register.
  void Drop(int element_count);
 
  void Call(Label* target) { call(target); }
  void Push(Register src) { push(src); }
  void Pop(Register dst) { pop(dst); }
 
  // Emit call to the code we are currently generating.
  void CallSelf() {
    Handle<Code> self(reinterpret_cast<Code**>(CodeObject().location()));
    call(self, RelocInfo::CODE_TARGET);
  }
 
  // Move if the registers are not identical.
  void Move(Register target, Register source);
 
  // Move a constant into a destination using the most efficient encoding.
  void Move(Register dst, const Immediate& x);
  void Move(const Operand& dst, const Immediate& x);
 
  // Move an immediate into an XMM register.
  void Move(XMMRegister dst, double val);
 
  // Push a handle value.
  void Push(Handle<Object> handle) { push(Immediate(handle)); }
  void Push(Smi* smi) { Push(Handle<Smi>(smi, isolate())); }
 
  Handle<Object> CodeObject() {
    DCHECK(!code_object_.is_null());
    return code_object_;
  }
 
  // Emit code for a truncating division by a constant. The dividend register is
  // unchanged, the result is in edx, and eax gets clobbered.
  void TruncatingDiv(Register dividend, int32_t divisor);
 
  // ---------------------------------------------------------------------------
  // StatsCounter support
 
  void SetCounter(StatsCounter* counter, int value);
  void IncrementCounter(StatsCounter* counter, int value);
  void DecrementCounter(StatsCounter* counter, int value);
  void IncrementCounter(Condition cc, StatsCounter* counter, int value);
  void DecrementCounter(Condition cc, 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 reason);
 
  // 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_has_frame(bool value) { has_frame_ = value; }
  bool has_frame() { return has_frame_; }
  inline bool AllowThisStubCall(CodeStub* stub);
 
  // ---------------------------------------------------------------------------
  // String utilities.
 
  // 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);
 
  // Check whether the instance type represents a flat one-byte string. Jump to
  // the label if not. If the instance type can be scratched specify same
  // register for both instance type and scratch.
  void JumpIfInstanceTypeIsNotSequentialOneByte(
      Register instance_type, Register scratch,
      Label* on_not_flat_one_byte_string);
 
  // Checks if both objects are sequential one-byte strings, and jumps to label
  // if either is not.
  void JumpIfNotBothSequentialOneByteStrings(
      Register object1, Register object2, Register scratch1, Register scratch2,
      Label* on_not_flat_one_byte_strings);
 
  // Checks if the given register or operand is a unique name
  void JumpIfNotUniqueNameInstanceType(Register reg, Label* not_unique_name,
                                       Label::Distance distance = Label::kFar) {
    JumpIfNotUniqueNameInstanceType(Operand(reg), not_unique_name, distance);
  }
 
  void JumpIfNotUniqueNameInstanceType(Operand operand, Label* not_unique_name,
                                       Label::Distance distance = Label::kFar);
 
  void EmitSeqStringSetCharCheck(Register string,
                                 Register index,
                                 Register value,
                                 uint32_t encoding_mask);
 
  static int SafepointRegisterStackIndex(Register reg) {
    return SafepointRegisterStackIndex(reg.code());
  }
 
  // Activation support.
  void EnterFrame(StackFrame::Type type);
  void LeaveFrame(StackFrame::Type type);
 
  // Expects object in eax and returns map with validated enum cache
  // in eax.  Assumes that any other register can be used as a scratch.
  void CheckEnumCache(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, conditional code is set to equal.
  void TestJSArrayForAllocationMemento(Register receiver_reg,
                                       Register scratch_reg,
                                       Label* no_memento_found);
 
  void JumpIfJSArrayHasAllocationMemento(Register receiver_reg,
                                         Register scratch_reg,
                                         Label* memento_found) {
    Label no_memento_found;
    TestJSArrayForAllocationMemento(receiver_reg, scratch_reg,
                                    &no_memento_found);
    j(equal, memento_found);
    bind(&no_memento_found);
  }
 
  // Jumps to found label if a prototype map has dictionary elements.
  void JumpIfDictionaryInPrototypeChain(Register object, Register scratch0,
                                        Register scratch1, Label* found);
 
 private:
  bool generating_stub_;
  bool has_frame_;
  // This handle will be patched with the code object on installation.
  Handle<Object> code_object_;
 
  // Helper functions for generating invokes.
  void InvokePrologue(const ParameterCount& expected,
                      const ParameterCount& actual,
                      Handle<Code> code_constant,
                      const Operand& code_operand,
                      Label* done,
                      bool* definitely_mismatches,
                      InvokeFlag flag,
                      Label::Distance done_distance,
                      const CallWrapper& call_wrapper = NullCallWrapper());
 
  void EnterExitFramePrologue();
  void EnterExitFrameEpilogue(int argc, bool save_doubles);
 
  void LeaveExitFrameEpilogue(bool restore_context);
 
  // Allocation support helpers.
  void LoadAllocationTopHelper(Register result,
                               Register scratch,
                               AllocationFlags flags);
 
  void UpdateAllocationTopHelper(Register result_end,
                                 Register scratch,
                                 AllocationFlags flags);
 
  // Helper for implementing JumpIfNotInNewSpace and JumpIfInNewSpace.
  void InNewSpace(Register object,
                  Register scratch,
                  Condition cc,
                  Label* condition_met,
                  Label::Distance condition_met_distance = Label::kFar);
 
  // Helper for finding the mark bits for an address.  Afterwards, the
  // bitmap register points at the word with the mark bits and the mask
  // the position of the first bit.  Uses ecx as scratch and leaves addr_reg
  // unchanged.
  inline void GetMarkBits(Register addr_reg,
                          Register bitmap_reg,
                          Register mask_reg);
 
  // Helper for throwing exceptions.  Compute a handler address and jump to
  // it.  See the implementation for register usage.
  void JumpToHandlerEntry();
 
  // Compute memory operands for safepoint stack slots.
  Operand SafepointRegisterSlot(Register reg);
  static int SafepointRegisterStackIndex(int reg_code);
 
  // Needs access to SafepointRegisterStackIndex for compiled frame
  // traversal.
  friend class StandardFrame;
};
 
 
// The code patcher is used to patch (typically) small parts of code e.g. for
// debugging and other types of instrumentation. When using the code patcher
// the exact number of bytes specified must be emitted. Is not legal to emit
// relocation information. If any of these constraints are violated it causes
// an assertion.
class CodePatcher {
 public:
  CodePatcher(byte* address, int size);
  virtual ~CodePatcher();
 
  // Macro assembler to emit code.
  MacroAssembler* masm() { return &masm_; }
 
 private:
  byte* address_;  // The address of the code being patched.
  int size_;  // Number of bytes of the expected patch size.
  MacroAssembler masm_;  // Macro assembler used to generate the code.
};
 
 
// -----------------------------------------------------------------------------
// Static helper functions.
 
// Generate an Operand for loading a field from an object.
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 FixedArrayElementOperand(Register array,
                                        Register index_as_smi,
                                        int additional_offset = 0) {
  int offset = FixedArray::kHeaderSize + additional_offset * kPointerSize;
  return FieldOperand(array, index_as_smi, times_half_pointer_size, offset);
}
 
 
inline Operand ContextOperand(Register context, int index) {
  return Operand(context, Context::SlotOffset(index));
}
 
 
inline Operand GlobalObjectOperand() {
  return ContextOperand(esi, Context::GLOBAL_OBJECT_INDEX);
}
 
 
// Generates an Operand for saving parameters after PrepareCallApiFunction.
Operand ApiParameterOperand(int index);
 
 
#ifdef GENERATED_CODE_COVERAGE
extern void LogGeneratedCodeCoverage(const char* file_line);
#define CODE_COVERAGE_STRINGIFY(x) #x
#define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
#define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
#define ACCESS_MASM(masm) {                                               \
    byte* ia32_coverage_function =                                        \
        reinterpret_cast<byte*>(FUNCTION_ADDR(LogGeneratedCodeCoverage)); \
    masm->pushfd();                                                       \
    masm->pushad();                                                       \
    masm->push(Immediate(reinterpret_cast<int>(&__FILE_LINE__)));         \
    masm->call(ia32_coverage_function, RelocInfo::RUNTIME_ENTRY);         \
    masm->pop(eax);                                                       \
    masm->popad();                                                        \
    masm->popfd();                                                        \
  }                                                                       \
  masm->
#else
#define ACCESS_MASM(masm) masm->
#endif
 
 
} }  // namespace v8::internal
 
#endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_