Move backend specific files to separate directories.

src/ia32/assembler-ia32.h

+// Copyright (c) 1994-2006 Sun Microsystems Inc.
+// All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// - Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+//
+// - Redistribution in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the distribution.
+//
+// - Neither the name of Sun Microsystems or the names of contributors may
+// be used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// The original source code covered by the above license above has been
+// modified significantly by Google Inc.
+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+
+// A light-weight IA32 Assembler.
+
+#ifndef V8_ASSEMBLER_IA32_H_
+#define V8_ASSEMBLER_IA32_H_
+
+namespace v8 { namespace internal {
+
+// CPU Registers.
+//
+// 1) We would prefer to use an enum, but enum values are assignment-
+// compatible with int, which has caused code-generation bugs.
+//
+// 2) We would prefer to use a class instead of a struct but we don't like
+// the register initialization to depend on the particular initialization
+// order (which appears to be different on OS X, Linux, and Windows for the
+// installed versions of C++ we tried). Using a struct permits C-style
+// "initialization". Also, the Register objects cannot be const as this
+// forces initialization stubs in MSVC, making us dependent on initialization
+// order.
+//
+// 3) By not using an enum, we are possibly preventing the compiler from
+// doing certain constant folds, which may significantly reduce the
+// code generated for some assembly instructions (because they boil down
+// to a few constants). If this is a problem, we could change the code
+// such that we use an enum in optimized mode, and the struct in debug
+// mode. This way we get the compile-time error checking in debug mode
+// and best performance in optimized code.
+//
+struct Register {
+  bool is_valid() const  { return 0 <= code_ && code_ < 8; }
+  bool is(Register reg) const  { return code_ == reg.code_; }
+  // eax, ebx, ecx and edx are byte registers, the rest are not.
+  bool is_byte_register() const  { return code_ <= 3; }
+  int code() const  {
+    ASSERT(is_valid());
+    return code_;
+  }
+  int bit() const  {
+    ASSERT(is_valid());
+    return 1 << code_;
+  }
+
+  // (unfortunately we can't make this private in a struct)
+  int code_;
+};
+
+const int kNumRegisters = 8;
+
+extern Register eax;
+extern Register ecx;
+extern Register edx;
+extern Register ebx;
+extern Register esp;
+extern Register ebp;
+extern Register esi;
+extern Register edi;
+extern Register no_reg;
+
+
+struct XMMRegister {
+  bool is_valid() const  { return 0 <= code_ && code_ < 2; }  // currently
+  int code() const  {
+    ASSERT(is_valid());
+    return code_;
+  }
+
+  int code_;
+};
+
+extern XMMRegister xmm0;
+extern XMMRegister xmm1;
+extern XMMRegister xmm2;
+extern XMMRegister xmm3;
+extern XMMRegister xmm4;
+extern XMMRegister xmm5;
+extern XMMRegister xmm6;
+extern XMMRegister xmm7;
+
+enum Condition {
+  // any value < 0 is considered no_condition
+  no_condition  = -1,
+
+  overflow      =  0,
+  no_overflow   =  1,
+  below         =  2,
+  above_equal   =  3,
+  equal         =  4,
+  not_equal     =  5,
+  below_equal   =  6,
+  above         =  7,
+  negative      =  8,
+  positive      =  9,
+  parity_even   = 10,
+  parity_odd    = 11,
+  less          = 12,
+  greater_equal = 13,
+  less_equal    = 14,
+  greater       = 15,
+
+  // aliases
+  carry         = below,
+  not_carry     = above_equal,
+  zero          = equal,
+  not_zero      = not_equal,
+  sign          = negative,
+  not_sign      = positive
+};
+
+
+// Returns the equivalent of !cc.
+// Negation of the default no_condition (-1) results in a non-default
+// no_condition value (-2). As long as tests for no_condition check
+// for condition < 0, this will work as expected.
+inline Condition NegateCondition(Condition cc);
+
+// Corresponds to transposing the operands of a comparison.
+inline Condition ReverseCondition(Condition cc) {
+  switch (cc) {
+    case below:
+      return above;
+    case above:
+      return below;
+    case above_equal:
+      return below_equal;
+    case below_equal:
+      return above_equal;
+    case less:
+      return greater;
+    case greater:
+      return less;
+    case greater_equal:
+      return less_equal;
+    case less_equal:
+      return greater_equal;
+    default:
+      return cc;
+  };
+}
+
+enum Hint {
+  no_hint = 0,
+  not_taken = 0x2e,
+  taken = 0x3e
+};
+
+// The result of negating a hint is as if the corresponding condition
+// were negated by NegateCondition.  That is, no_hint is mapped to
+// itself and not_taken and taken are mapped to each other.
+inline Hint NegateHint(Hint hint) {
+  return (hint == no_hint)
+      ? no_hint
+      : ((hint == not_taken) ? taken : not_taken);
+}
+
+
+// -----------------------------------------------------------------------------
+// Machine instruction Immediates
+
+class Immediate BASE_EMBEDDED {
+ public:
+  inline explicit Immediate(int x);
+  inline explicit Immediate(const char* s);
+  inline explicit Immediate(const ExternalReference& ext);
+  inline explicit Immediate(Handle<Object> handle);
+  inline explicit Immediate(Smi* value);
+
+  static Immediate CodeRelativeOffset(Label* label) {
+    return Immediate(label);
+  }
+
+  bool is_zero() const { return x_ == 0 && rmode_ == RelocInfo::NONE; }
+  bool is_int8() const {
+    return -128 <= x_ && x_ < 128 && rmode_ == RelocInfo::NONE;
+  }
+  bool is_int16() const {
+    return -32768 <= x_ && x_ < 32768 && rmode_ == RelocInfo::NONE;
+  }
+
+ private:
+  inline explicit Immediate(Label* value);
+
+  int x_;
+  RelocInfo::Mode rmode_;
+
+  friend class Assembler;
+};
+
+
+// -----------------------------------------------------------------------------
+// Machine instruction Operands
+
+enum ScaleFactor {
+  times_1 = 0,
+  times_2 = 1,
+  times_4 = 2,
+  times_8 = 3
+};
+
+
+class Operand BASE_EMBEDDED {
+ public:
+  // reg
+  INLINE(explicit Operand(Register reg));
+
+  // [disp/r]
+  INLINE(explicit Operand(int32_t disp, RelocInfo::Mode rmode));
+  // disp only must always be relocated
+
+  // [base + disp/r]
+  explicit Operand(Register base, int32_t disp,
+                   RelocInfo::Mode rmode = RelocInfo::NONE);
+
+  // [base + index*scale + disp/r]
+  explicit Operand(Register base,
+                   Register index,
+                   ScaleFactor scale,
+                   int32_t disp,
+                   RelocInfo::Mode rmode = RelocInfo::NONE);
+
+  // [index*scale + disp/r]
+  explicit Operand(Register index,
+                   ScaleFactor scale,
+                   int32_t disp,
+                   RelocInfo::Mode rmode = RelocInfo::NONE);
+
+  static Operand StaticVariable(const ExternalReference& ext) {
+    return Operand(reinterpret_cast<int32_t>(ext.address()),
+                   RelocInfo::EXTERNAL_REFERENCE);
+  }
+
+  static Operand StaticArray(Register index,
+                             ScaleFactor scale,
+                             const ExternalReference& arr) {
+    return Operand(index, scale, reinterpret_cast<int32_t>(arr.address()),
+                   RelocInfo::EXTERNAL_REFERENCE);
+  }
+
+  // Returns true if this Operand is a wrapper for the specified register.
+  bool is_reg(Register reg) const;
+
+ private:
+  byte buf_[6];
+  // The number of bytes in buf_.
+  unsigned int len_;
+  // Only valid if len_ > 4.
+  RelocInfo::Mode rmode_;
+
+  // Set the ModRM byte without an encoded 'reg' register. The
+  // register is encoded later as part of the emit_operand operation.
+  inline void set_modrm(int mod, Register rm);
+
+  inline void set_sib(ScaleFactor scale, Register index, Register base);
+  inline void set_disp8(int8_t disp);
+  inline void set_dispr(int32_t disp, RelocInfo::Mode rmode);
+
+  friend class Assembler;
+};
+
+
+// -----------------------------------------------------------------------------
+// A Displacement describes the 32bit immediate field of an instruction which
+// may be used together with a Label in order to refer to a yet unknown code
+// position. Displacements stored in the instruction stream are used to describe
+// the instruction and to chain a list of instructions using the same Label.
+// A Displacement contains 2 different fields:
+//
+// next field: position of next displacement in the chain (0 = end of list)
+// type field: instruction type
+//
+// A next value of null (0) indicates the end of a chain (note that there can
+// be no displacement at position zero, because there is always at least one
+// instruction byte before the displacement).
+//
+// Displacement _data field layout
+//
+// |31.....2|1......0|
+// [  next  |  type  |
+
+class Displacement BASE_EMBEDDED {
+ public:
+  enum Type {
+    UNCONDITIONAL_JUMP,
+    CODE_RELATIVE,
+    OTHER
+  };
+
+  int data() const { return data_; }
+  Type type() const { return TypeField::decode(data_); }
+  void next(Label* L) const {
+    int n = NextField::decode(data_);
+    n > 0 ? L->link_to(n) : L->Unuse();
+  }
+  void link_to(Label* L) { init(L, type()); }
+
+  explicit Displacement(int data) { data_ = data; }
+
+  Displacement(Label* L, Type type) { init(L, type); }
+
+  void print() {
+    PrintF("%s (%x) ", (type() == UNCONDITIONAL_JUMP ? "jmp" : "[other]"),
+                       NextField::decode(data_));
+  }
+
+ private:
+  int data_;
+
+  class TypeField: public BitField<Type, 0, 2> {};
+  class NextField: public BitField<int,  2, 32-2> {};
+
+  void init(Label* L, Type type);
+};
+
+
+
+// CpuFeatures keeps track of which features are supported by the target CPU.
+// Supported features must be enabled by a Scope before use.
+// Example:
+//   if (CpuFeatures::IsSupported(SSE2)) {
+//     CpuFeatures::Scope fscope(SSE2);
+//     // Generate SSE2 floating point code.
+//   } else {
+//     // Generate standard x87 floating point code.
+//   }
+class CpuFeatures : public AllStatic {
+ public:
+  // Feature flags bit positions. They are mostly based on the CPUID spec.
+  // (We assign CPUID itself to one of the currently reserved bits --
+  // feel free to change this if needed.)
+  enum Feature { SSE3 = 32, SSE2 = 26, CMOV = 15, RDTSC = 4, CPUID = 10 };
+  // Detect features of the target CPU. Set safe defaults if the serializer
+  // is enabled (snapshots must be portable).
+  static void Probe();
+  // Check whether a feature is supported by the target CPU.
+  static bool IsSupported(Feature f) {
+    return (supported_ & (static_cast<uint64_t>(1) << f)) != 0;
+  }
+  // Check whether a feature is currently enabled.
+  static bool IsEnabled(Feature f) {
+    return (enabled_ & (static_cast<uint64_t>(1) << f)) != 0;
+  }
+  // Enable a specified feature within a scope.
+  class Scope BASE_EMBEDDED {
+#ifdef DEBUG
+   public:
+    explicit Scope(Feature f) {
+      ASSERT(CpuFeatures::IsSupported(f));
+      old_enabled_ = CpuFeatures::enabled_;
+      CpuFeatures::enabled_ |= (static_cast<uint64_t>(1) << f);
+    }
+    ~Scope() { CpuFeatures::enabled_ = old_enabled_; }
+   private:
+    uint64_t old_enabled_;
+#else
+   public:
+    explicit Scope(Feature f) {}
+#endif
+  };
+ private:
+  static uint64_t supported_;
+  static uint64_t enabled_;
+};
+
+
+class Assembler : public Malloced {
+ private:
+  // The relocation writer's position is kGap bytes below the end of
+  // the generated instructions. This leaves enough space for the
+  // longest possible ia32 instruction (17 bytes as of 9/26/06) and
+  // allows for a single, fast space check per instruction.
+  static const int kGap = 32;
+
+ public:
+  // Create an assembler. Instructions and relocation information are emitted
+  // into a buffer, with the instructions starting from the beginning and the
+  // relocation information starting from the end of the buffer. See CodeDesc
+  // for a detailed comment on the layout (globals.h).
+  //
+  // If the provided buffer is NULL, the assembler allocates and grows its own
+  // buffer, and buffer_size determines the initial buffer size. The buffer is
+  // owned by the assembler and deallocated upon destruction of the assembler.
+  //
+  // If the provided buffer is not NULL, the assembler uses the provided buffer
+  // for code generation and assumes its size to be buffer_size. If the buffer
+  // is too small, a fatal error occurs. No deallocation of the buffer is done
+  // upon destruction of the assembler.
+  Assembler(void* buffer, int buffer_size);
+  ~Assembler();
+
+  // GetCode emits any pending (non-emitted) code and fills the descriptor
+  // desc. GetCode() is idempotent; it returns the same result if no other
+  // Assembler functions are invoked in between GetCode() calls.
+  void GetCode(CodeDesc* desc);
+
+  // Read/Modify the code target in the branch/call instruction at pc.
+  inline static Address target_address_at(Address pc);
+  inline static void set_target_address_at(Address pc, Address target);
+
+  // Distance between the address of the code target in the call instruction
+  // and the return address
+  static const int kTargetAddrToReturnAddrDist = kPointerSize;
+
+
+  // ---------------------------------------------------------------------------
+  // Code generation
+  //
+  // - function names correspond one-to-one to ia32 instruction mnemonics
+  // - unless specified otherwise, instructions operate on 32bit operands
+  // - instructions on 8bit (byte) operands/registers have a trailing '_b'
+  // - instructions on 16bit (word) operands/registers have a trailing '_w'
+  // - naming conflicts with C++ keywords are resolved via a trailing '_'
+
+  // NOTE ON INTERFACE: Currently, the interface is not very consistent
+  // in the sense that some operations (e.g. mov()) can be called in more
+  // the one way to generate the same instruction: The Register argument
+  // can in some cases be replaced with an Operand(Register) argument.
+  // This should be cleaned up and made more orthogonal. The questions
+  // is: should we always use Operands instead of Registers where an
+  // Operand is possible, or should we have a Register (overloaded) form
+  // instead? We must be careful to make sure that the selected instruction
+  // is obvious from the parameters to avoid hard-to-find code generation
+  // bugs.
+
+  // Insert the smallest number of nop instructions
+  // possible to align the pc offset to a multiple
+  // of m. m must be a power of 2.
+  void Align(int m);
+
+  // Stack
+  void pushad();
+  void popad();
+
+  void pushfd();
+  void popfd();
+
+  void push(const Immediate& x);
+  void push(Register src);
+  void push(const Operand& src);
+  void push(Label* label, RelocInfo::Mode relocation_mode);
+
+  void pop(Register dst);
+  void pop(const Operand& dst);
+
+  void enter(const Immediate& size);
+  void leave();
+
+  // Moves
+  void mov_b(Register dst, const Operand& src);
+  void mov_b(const Operand& dst, int8_t imm8);
+  void mov_b(const Operand& dst, Register src);
+
+  void mov_w(Register dst, const Operand& src);
+  void mov_w(const Operand& dst, Register src);
+
+  void mov(Register dst, int32_t imm32);
+  void mov(Register dst, const Immediate& x);
+  void mov(Register dst, Handle<Object> handle);
+  void mov(Register dst, const Operand& src);
+  void mov(Register dst, Register src);
+  void mov(const Operand& dst, const Immediate& x);
+  void mov(const Operand& dst, Handle<Object> handle);
+  void mov(const Operand& dst, Register src);
+
+  void movsx_b(Register dst, const Operand& src);
+
+  void movsx_w(Register dst, const Operand& src);
+
+  void movzx_b(Register dst, const Operand& src);
+
+  void movzx_w(Register dst, const Operand& src);
+
+  // Conditional moves
+  void cmov(Condition cc, Register dst, int32_t imm32);
+  void cmov(Condition cc, Register dst, Handle<Object> handle);
+  void cmov(Condition cc, Register dst, const Operand& src);
+
+  // Exchange two registers
+  void xchg(Register dst, Register src);
+
+  // Arithmetics
+  void adc(Register dst, int32_t imm32);
+  void adc(Register dst, const Operand& src);
+
+  void add(Register dst, const Operand& src);
+  void add(const Operand& dst, const Immediate& x);
+
+  void and_(Register dst, int32_t imm32);
+  void and_(Register dst, const Operand& src);
+  void and_(const Operand& src, Register dst);
+  void and_(const Operand& dst, const Immediate& x);
+
+  void cmpb(const Operand& op, int8_t imm8);
+  void cmpb_al(const Operand& op);
+  void cmpw_ax(const Operand& op);
+  void cmpw(const Operand& op, Immediate imm16);
+  void cmp(Register reg, int32_t imm32);
+  void cmp(Register reg, Handle<Object> handle);
+  void cmp(Register reg, const Operand& op);
+  void cmp(const Operand& op, const Immediate& imm);
+
+  void dec_b(Register dst);
+
+  void dec(Register dst);
+  void dec(const Operand& dst);
+
+  void cdq();
+
+  void idiv(Register src);
+
+  void imul(Register dst, const Operand& src);
+  void imul(Register dst, Register src, int32_t imm32);
+
+  void inc(Register dst);
+  void inc(const Operand& dst);
+
+  void lea(Register dst, const Operand& src);
+
+  void mul(Register src);
+
+  void neg(Register dst);
+
+  void not_(Register dst);
+
+  void or_(Register dst, int32_t imm32);
+  void or_(Register dst, const Operand& src);
+  void or_(const Operand& dst, Register src);
+  void or_(const Operand& dst, const Immediate& x);
+
+  void rcl(Register dst, uint8_t imm8);
+
+  void sar(Register dst, uint8_t imm8);
+  void sar(Register dst);
+
+  void sbb(Register dst, const Operand& src);
+
+  void shld(Register dst, const Operand& src);
+
+  void shl(Register dst, uint8_t imm8);
+  void shl(Register dst);
+
+  void shrd(Register dst, const Operand& src);
+
+  void shr(Register dst, uint8_t imm8);
+  void shr(Register dst);
+  void shr_cl(Register dst);
+
+  void sub(const Operand& dst, const Immediate& x);
+  void sub(Register dst, const Operand& src);
+  void sub(const Operand& dst, Register src);
+
+  void test(Register reg, const Immediate& imm);
+  void test(Register reg, const Operand& op);
+  void test(const Operand& op, const Immediate& imm);
+
+  void xor_(Register dst, int32_t imm32);
+  void xor_(Register dst, const Operand& src);
+  void xor_(const Operand& src, Register dst);
+  void xor_(const Operand& dst, const Immediate& x);
+
+  // Bit operations.
+  void bt(const Operand& dst, Register src);
+  void bts(const Operand& dst, Register src);
+
+  // Miscellaneous
+  void hlt();
+  void int3();
+  void nop();
+  void rdtsc();
+  void ret(int imm16);
+
+  // Label operations & relative jumps (PPUM Appendix D)
+  //
+  // Takes a branch opcode (cc) and a label (L) and generates
+  // either a backward branch or a forward branch and links it
+  // to the label fixup chain. Usage:
+  //
+  // Label L;    // unbound label
+  // j(cc, &L);  // forward branch to unbound label
+  // bind(&L);   // bind label to the current pc
+  // j(cc, &L);  // backward branch to bound label
+  // bind(&L);   // illegal: a label may be bound only once
+  //
+  // Note: The same Label can be used for forward and backward branches
+  // but it may be bound only once.
+
+  void bind(Label* L);  // binds an unbound label L to the current code position
+
+  // Calls
+  void call(Label* L);
+  void call(byte* entry, RelocInfo::Mode rmode);
+  void call(const Operand& adr);
+  void call(Handle<Code> code, RelocInfo::Mode rmode);
+
+  // Jumps
+  void jmp(Label* L);  // unconditional jump to L
+  void jmp(byte* entry, RelocInfo::Mode rmode);
+  void jmp(const Operand& adr);
+  void jmp(Handle<Code> code, RelocInfo::Mode rmode);
+
+  // Conditional jumps
+  void j(Condition cc, Label* L, Hint hint = no_hint);
+  void j(Condition cc, byte* entry, RelocInfo::Mode rmode, Hint hint = no_hint);
+  void j(Condition cc, Handle<Code> code, Hint hint = no_hint);
+
+  // Floating-point operations
+  void fld(int i);
+
+  void fld1();
+  void fldz();
+
+  void fld_s(const Operand& adr);
+  void fld_d(const Operand& adr);
+
+  void fstp_s(const Operand& adr);
+  void fstp_d(const Operand& adr);
+
+  void fild_s(const Operand& adr);
+  void fild_d(const Operand& adr);
+
+  void fist_s(const Operand& adr);
+
+  void fistp_s(const Operand& adr);
+  void fistp_d(const Operand& adr);
+
+  void fisttp_s(const Operand& adr);
+
+  void fabs();
+  void fchs();
+
+  void fadd(int i);
+  void fsub(int i);
+  void fmul(int i);
+  void fdiv(int i);
+
+  void fisub_s(const Operand& adr);
+
+  void faddp(int i = 1);
+  void fsubp(int i = 1);
+  void fsubrp(int i = 1);
+  void fmulp(int i = 1);
+  void fdivp(int i = 1);
+  void fprem();
+  void fprem1();
+
+  void fxch(int i = 1);
+  void fincstp();
+  void ffree(int i = 0);
+
+  void ftst();
+  void fucomp(int i);
+  void fucompp();
+  void fcompp();
+  void fnstsw_ax();
+  void fwait();
+  void fnclex();
+
+  void frndint();
+
+  void sahf();
+  void setcc(Condition cc, Register reg);
+
+  void cpuid();
+
+  // SSE2 instructions
+  void cvttss2si(Register dst, const Operand& src);
+  void cvttsd2si(Register dst, const Operand& src);
+
+  void cvtsi2sd(XMMRegister dst, const Operand& src);
+
+  void addsd(XMMRegister dst, XMMRegister src);
+  void subsd(XMMRegister dst, XMMRegister src);
+  void mulsd(XMMRegister dst, XMMRegister src);
+  void divsd(XMMRegister dst, XMMRegister src);
+
+  // Use either movsd or movlpd.
+  void movdbl(XMMRegister dst, const Operand& src);
+  void movdbl(const Operand& dst, XMMRegister src);
+
+  // Debugging
+  void Print();
+
+  // Check the code size generated from label to here.
+  int SizeOfCodeGeneratedSince(Label* l) { return pc_offset() - l->pos(); }
+
+  // Mark address of the ExitJSFrame code.
+  void RecordJSReturn();
+
+  // Record a comment relocation entry that can be used by a disassembler.
+  // Use --debug_code to enable.
+  void RecordComment(const char* msg);
+
+  void RecordPosition(int pos);
+  void RecordStatementPosition(int pos);
+  void WriteRecordedPositions();
+
+  // Writes a single word of data in the code stream.
+  // Used for inline tables, e.g., jump-tables.
+  void dd(uint32_t data, RelocInfo::Mode reloc_info);
+
+  // Writes the absolute address of a bound label at the given position in
+  // the generated code. That positions should have the relocation mode
+  // internal_reference!
+  void WriteInternalReference(int position, const Label& bound_label);
+
+  int pc_offset() const  { return pc_ - buffer_; }
+  int current_statement_position() const { return current_statement_position_; }
+  int current_position() const  { return current_position_; }
+
+  // Check if there is less than kGap bytes available in the buffer.
+  // If this is the case, we need to grow the buffer before emitting
+  // an instruction or relocation information.
+  inline bool overflow() const { return pc_ >= reloc_info_writer.pos() - kGap; }
+
+  // Get the number of bytes available in the buffer.
+  inline int available_space() const { return reloc_info_writer.pos() - pc_; }
+
+  // Avoid overflows for displacements etc.
+  static const int kMaximalBufferSize = 512*MB;
+  static const int kMinimalBufferSize = 4*KB;
+
+ protected:
+  void movsd(XMMRegister dst, const Operand& src);
+  void movsd(const Operand& dst, XMMRegister src);
+
+  void emit_sse_operand(XMMRegister reg, const Operand& adr);
+  void emit_sse_operand(XMMRegister dst, XMMRegister src);
+
+
+ private:
+  byte* addr_at(int pos)  { return buffer_ + pos; }
+  byte byte_at(int pos)  { return buffer_[pos]; }
+  uint32_t long_at(int pos)  {
+    return *reinterpret_cast<uint32_t*>(addr_at(pos));
+  }
+  void long_at_put(int pos, uint32_t x)  {
+    *reinterpret_cast<uint32_t*>(addr_at(pos)) = x;
+  }
+
+  // code emission
+  void GrowBuffer();
+  inline void emit(uint32_t x);
+  inline void emit(Handle<Object> handle);
+  inline void emit(uint32_t x, RelocInfo::Mode rmode);
+  inline void emit(const Immediate& x);
+  inline void emit_w(const Immediate& x);
+
+  // Emit the code-object-relative offset of the label's position
+  inline void emit_code_relative_offset(Label* label);
+
+  // instruction generation
+  void emit_arith_b(int op1, int op2, Register dst, int imm8);
+
+  // Emit a basic arithmetic instruction (i.e. first byte of the family is 0x81)
+  // with a given destination expression and an immediate operand.  It attempts
+  // to use the shortest encoding possible.
+  // sel specifies the /n in the modrm byte (see the Intel PRM).
+  void emit_arith(int sel, Operand dst, const Immediate& x);
+
+  void emit_operand(Register reg, const Operand& adr);
+
+  void emit_farith(int b1, int b2, int i);
+
+  // labels
+  void print(Label* L);
+  void bind_to(Label* L, int pos);
+  void link_to(Label* L, Label* appendix);
+
+  // displacements
+  inline Displacement disp_at(Label* L);
+  inline void disp_at_put(Label* L, Displacement disp);
+  inline void emit_disp(Label* L, Displacement::Type type);
+
+  // record reloc info for current pc_
+  void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
+
+  friend class CodePatcher;
+  friend class EnsureSpace;
+
+  // Code buffer:
+  // The buffer into which code and relocation info are generated.
+  byte* buffer_;
+  int buffer_size_;
+  // True if the assembler owns the buffer, false if buffer is external.
+  bool own_buffer_;
+
+  // code generation
+  byte* pc_;  // the program counter; moves forward
+  RelocInfoWriter reloc_info_writer;
+
+  // push-pop elimination
+  byte* last_pc_;
+
+  // source position information
+  int current_statement_position_;
+  int current_position_;
+  int written_statement_position_;
+  int written_position_;
+};
+
+
+// Helper class that ensures that there is enough space for generating
+// instructions and relocation information.  The constructor makes
+// sure that there is enough space and (in debug mode) the destructor
+// checks that we did not generate too much.
+class EnsureSpace BASE_EMBEDDED {
+ public:
+  explicit EnsureSpace(Assembler* assembler) : assembler_(assembler) {
+    if (assembler_->overflow()) assembler_->GrowBuffer();
+#ifdef DEBUG
+    space_before_ = assembler_->available_space();
+#endif
+  }
+
+#ifdef DEBUG
+  ~EnsureSpace() {
+    int bytes_generated = space_before_ - assembler_->available_space();
+    ASSERT(bytes_generated < assembler_->kGap);
+  }
+#endif
+
+ private:
+  Assembler* assembler_;
+#ifdef DEBUG
+  int space_before_;
+#endif
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_ASSEMBLER_IA32_H_