Move backend specific files to separate directories.

src/arm/assembler-arm.h

Index: src/arm/assembler-arm.h
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+// 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 ARM Assembler
+// Generates user mode instructions for the ARM architecture up to version 5
+
+#ifndef V8_ASSEMBLER_ARM_H_
+#define V8_ASSEMBLER_ARM_H_
+
+#include "assembler.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.
+//
+// Core register
+struct Register {
+  bool is_valid() const  { return 0 <= code_ && code_ < 16; }
+  bool is(Register reg) const  { return code_ == reg.code_; }
+  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 = 16;
+
+extern Register no_reg;
+extern Register r0;
+extern Register r1;
+extern Register r2;
+extern Register r3;
+extern Register r4;
+extern Register r5;
+extern Register r6;
+extern Register r7;
+extern Register r8;
+extern Register r9;
+extern Register r10;
+extern Register fp;
+extern Register ip;
+extern Register sp;
+extern Register lr;
+extern Register pc;
+
+
+// Coprocessor register
+struct CRegister {
+  bool is_valid() const  { return 0 <= code_ && code_ < 16; }
+  bool is(CRegister creg) const  { return code_ == creg.code_; }
+  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_;
+};
+
+
+extern CRegister no_creg;
+extern CRegister cr0;
+extern CRegister cr1;
+extern CRegister cr2;
+extern CRegister cr3;
+extern CRegister cr4;
+extern CRegister cr5;
+extern CRegister cr6;
+extern CRegister cr7;
+extern CRegister cr8;
+extern CRegister cr9;
+extern CRegister cr10;
+extern CRegister cr11;
+extern CRegister cr12;
+extern CRegister cr13;
+extern CRegister cr14;
+extern CRegister cr15;
+
+
+// Coprocessor number
+enum Coprocessor {
+  p0  = 0,
+  p1  = 1,
+  p2  = 2,
+  p3  = 3,
+  p4  = 4,
+  p5  = 5,
+  p6  = 6,
+  p7  = 7,
+  p8  = 8,
+  p9  = 9,
+  p10 = 10,
+  p11 = 11,
+  p12 = 12,
+  p13 = 13,
+  p14 = 14,
+  p15 = 15
+};
+
+
+// Condition field in instructions
+enum Condition {
+  eq =  0 << 28,
+  ne =  1 << 28,
+  cs =  2 << 28,
+  hs =  2 << 28,
+  cc =  3 << 28,
+  lo =  3 << 28,
+  mi =  4 << 28,
+  pl =  5 << 28,
+  vs =  6 << 28,
+  vc =  7 << 28,
+  hi =  8 << 28,
+  ls =  9 << 28,
+  ge = 10 << 28,
+  lt = 11 << 28,
+  gt = 12 << 28,
+  le = 13 << 28,
+  al = 14 << 28
+};
+
+
+// Returns the equivalent of !cc.
+INLINE(Condition NegateCondition(Condition cc));
+
+
+// Corresponds to transposing the operands of a comparison.
+inline Condition ReverseCondition(Condition cc) {
+  switch (cc) {
+    case lo:
+      return hi;
+    case hi:
+      return lo;
+    case hs:
+      return ls;
+    case ls:
+      return hs;
+    case lt:
+      return gt;
+    case gt:
+      return lt;
+    case ge:
+      return le;
+    case le:
+      return ge;
+    default:
+      return cc;
+  };
+}
+
+
+// Branch hints are not used on the ARM.  They are defined so that they can
+// appear in shared function signatures, but will be ignored in ARM
+// implementations.
+enum Hint { no_hint };
+
+// Hints are not used on the arm.  Negating is trivial.
+inline Hint NegateHint(Hint ignored) { return no_hint; }
+
+
+// -----------------------------------------------------------------------------
+// Addressing modes and instruction variants
+
+// Shifter operand shift operation
+enum ShiftOp {
+  LSL = 0 << 5,
+  LSR = 1 << 5,
+  ASR = 2 << 5,
+  ROR = 3 << 5,
+  RRX = -1
+};
+
+
+// Condition code updating mode
+enum SBit {
+  SetCC   = 1 << 20,  // set condition code
+  LeaveCC = 0 << 20   // leave condition code unchanged
+};
+
+
+// Status register selection
+enum SRegister {
+  CPSR = 0 << 22,
+  SPSR = 1 << 22
+};
+
+
+// Status register fields
+enum SRegisterField {
+  CPSR_c = CPSR | 1 << 16,
+  CPSR_x = CPSR | 1 << 17,
+  CPSR_s = CPSR | 1 << 18,
+  CPSR_f = CPSR | 1 << 19,
+  SPSR_c = SPSR | 1 << 16,
+  SPSR_x = SPSR | 1 << 17,
+  SPSR_s = SPSR | 1 << 18,
+  SPSR_f = SPSR | 1 << 19
+};
+
+// Status register field mask (or'ed SRegisterField enum values)
+typedef uint32_t SRegisterFieldMask;
+
+
+// Memory operand addressing mode
+enum AddrMode {
+  // bit encoding P U W
+  Offset       = (8|4|0) << 21,  // offset (without writeback to base)
+  PreIndex     = (8|4|1) << 21,  // pre-indexed addressing with writeback
+  PostIndex    = (0|4|0) << 21,  // post-indexed addressing with writeback
+  NegOffset    = (8|0|0) << 21,  // negative offset (without writeback to base)
+  NegPreIndex  = (8|0|1) << 21,  // negative pre-indexed with writeback
+  NegPostIndex = (0|0|0) << 21   // negative post-indexed with writeback
+};
+
+
+// Load/store multiple addressing mode
+enum BlockAddrMode {
+  // bit encoding P U W
+  da           = (0|0|0) << 21,  // decrement after
+  ia           = (0|4|0) << 21,  // increment after
+  db           = (8|0|0) << 21,  // decrement before
+  ib           = (8|4|0) << 21,  // increment before
+  da_w         = (0|0|1) << 21,  // decrement after with writeback to base
+  ia_w         = (0|4|1) << 21,  // increment after with writeback to base
+  db_w         = (8|0|1) << 21,  // decrement before with writeback to base
+  ib_w         = (8|4|1) << 21   // increment before with writeback to base
+};
+
+
+// Coprocessor load/store operand size
+enum LFlag {
+  Long  = 1 << 22,  // long load/store coprocessor
+  Short = 0 << 22   // short load/store coprocessor
+};
+
+
+// -----------------------------------------------------------------------------
+// Machine instruction Operands
+
+// Class Operand represents a shifter operand in data processing instructions
+class Operand BASE_EMBEDDED {
+ public:
+  // immediate
+  INLINE(explicit Operand(int32_t immediate,
+         RelocInfo::Mode rmode = RelocInfo::NONE));
+  INLINE(explicit Operand(const ExternalReference& f));
+  INLINE(explicit Operand(const char* s));
+  INLINE(explicit Operand(Object** opp));
+  INLINE(explicit Operand(Context** cpp));
+  explicit Operand(Handle<Object> handle);
+  INLINE(explicit Operand(Smi* value));
+
+  // rm
+  INLINE(explicit Operand(Register rm));
+
+  // rm <shift_op> shift_imm
+  explicit Operand(Register rm, ShiftOp shift_op, int shift_imm);
+
+  // rm <shift_op> rs
+  explicit Operand(Register rm, ShiftOp shift_op, Register rs);
+
+  // Return true if this is a register operand.
+  INLINE(bool is_reg() const);
+
+  Register rm() const { return rm_; }
+
+ private:
+  Register rm_;
+  Register rs_;
+  ShiftOp shift_op_;
+  int shift_imm_;  // valid if rm_ != no_reg && rs_ == no_reg
+  int32_t imm32_;  // valid if rm_ == no_reg
+  RelocInfo::Mode rmode_;
+
+  friend class Assembler;
+};
+
+
+// Class MemOperand represents a memory operand in load and store instructions
+class MemOperand BASE_EMBEDDED {
+ public:
+  // [rn +/- offset]      Offset/NegOffset
+  // [rn +/- offset]!     PreIndex/NegPreIndex
+  // [rn], +/- offset     PostIndex/NegPostIndex
+  // offset is any signed 32-bit value; offset is first loaded to register ip if
+  // it does not fit the addressing mode (12-bit unsigned and sign bit)
+  explicit MemOperand(Register rn, int32_t offset = 0, AddrMode am = Offset);
+
+  // [rn +/- rm]          Offset/NegOffset
+  // [rn +/- rm]!         PreIndex/NegPreIndex
+  // [rn], +/- rm         PostIndex/NegPostIndex
+  explicit MemOperand(Register rn, Register rm, AddrMode am = Offset);
+
+  // [rn +/- rm <shift_op> shift_imm]      Offset/NegOffset
+  // [rn +/- rm <shift_op> shift_imm]!     PreIndex/NegPreIndex
+  // [rn], +/- rm <shift_op> shift_imm     PostIndex/NegPostIndex
+  explicit MemOperand(Register rn, Register rm,
+                      ShiftOp shift_op, int shift_imm, AddrMode am = Offset);
+
+ private:
+  Register rn_;  // base
+  Register rm_;  // register offset
+  int32_t offset_;  // valid if rm_ == no_reg
+  ShiftOp shift_op_;
+  int shift_imm_;  // valid if rm_ != no_reg && rs_ == no_reg
+  AddrMode am_;  // bits P, U, and W
+
+  friend class Assembler;
+};
+
+
+typedef int32_t Instr;
+
+
+class Assembler : public Malloced {
+ 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);
+
+  // 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
+
+  // Returns the branch offset to the given label from the current code position
+  // Links the label to the current position if it is still unbound
+  // Manages the jump elimination optimization if the second parameter is true.
+  int branch_offset(Label* L, bool jump_elimination_allowed);
+
+  // Return the address in the constant pool of the code target address used by
+  // the branch/call instruction at pc.
+  INLINE(static Address target_address_address_at(Address pc));
+
+  // Read/Modify the code target address 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 instruction referring to the address of the call
+  // target (ldr pc, [target addr in const pool]) and the return address
+  static const int kTargetAddrToReturnAddrDist = sizeof(Instr);
+
+
+  // ---------------------------------------------------------------------------
+  // Code generation
+
+  // 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 (>= 4).
+  void Align(int m);
+
+  // Branch instructions
+  void b(int branch_offset, Condition cond = al);
+  void bl(int branch_offset, Condition cond = al);
+  void blx(int branch_offset);  // v5 and above
+  void blx(Register target, Condition cond = al);  // v5 and above
+  void bx(Register target, Condition cond = al);  // v5 and above, plus v4t
+
+  // Convenience branch instructions using labels
+  void b(Label* L, Condition cond = al)  {
+    b(branch_offset(L, cond == al), cond);
+  }
+  void b(Condition cond, Label* L)  { b(branch_offset(L, cond == al), cond); }
+  void bl(Label* L, Condition cond = al)  { bl(branch_offset(L, false), cond); }
+  void bl(Condition cond, Label* L)  { bl(branch_offset(L, false), cond); }
+  void blx(Label* L)  { blx(branch_offset(L, false)); }  // v5 and above
+
+  // Data-processing instructions
+  void and_(Register dst, Register src1, const Operand& src2,
+            SBit s = LeaveCC, Condition cond = al);
+
+  void eor(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void sub(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+  void sub(Register dst, Register src1, Register src2,
+           SBit s = LeaveCC, Condition cond = al) {
+    sub(dst, src1, Operand(src2), s, cond);
+  }
+
+  void rsb(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void add(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void adc(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void sbc(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void rsc(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void tst(Register src1, const Operand& src2, Condition cond = al);
+  void tst(Register src1, Register src2, Condition cond = al) {
+    tst(src1, Operand(src2), cond);
+  }
+
+  void teq(Register src1, const Operand& src2, Condition cond = al);
+
+  void cmp(Register src1, const Operand& src2, Condition cond = al);
+  void cmp(Register src1, Register src2, Condition cond = al) {
+    cmp(src1, Operand(src2), cond);
+  }
+
+  void cmn(Register src1, const Operand& src2, Condition cond = al);
+
+  void orr(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+  void orr(Register dst, Register src1, Register src2,
+           SBit s = LeaveCC, Condition cond = al) {
+    orr(dst, src1, Operand(src2), s, cond);
+  }
+
+  void mov(Register dst, const Operand& src,
+           SBit s = LeaveCC, Condition cond = al);
+  void mov(Register dst, Register src, SBit s = LeaveCC, Condition cond = al) {
+    mov(dst, Operand(src), s, cond);
+  }
+
+  void bic(Register dst, Register src1, const Operand& src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void mvn(Register dst, const Operand& src,
+           SBit s = LeaveCC, Condition cond = al);
+
+  // Multiply instructions
+
+  void mla(Register dst, Register src1, Register src2, Register srcA,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void mul(Register dst, Register src1, Register src2,
+           SBit s = LeaveCC, Condition cond = al);
+
+  void smlal(Register dstL, Register dstH, Register src1, Register src2,
+             SBit s = LeaveCC, Condition cond = al);
+
+  void smull(Register dstL, Register dstH, Register src1, Register src2,
+             SBit s = LeaveCC, Condition cond = al);
+
+  void umlal(Register dstL, Register dstH, Register src1, Register src2,
+             SBit s = LeaveCC, Condition cond = al);
+
+  void umull(Register dstL, Register dstH, Register src1, Register src2,
+             SBit s = LeaveCC, Condition cond = al);
+
+  // Miscellaneous arithmetic instructions
+
+  void clz(Register dst, Register src, Condition cond = al);  // v5 and above
+
+  // Status register access instructions
+
+  void mrs(Register dst, SRegister s, Condition cond = al);
+  void msr(SRegisterFieldMask fields, const Operand& src, Condition cond = al);
+
+  // Load/Store instructions
+  void ldr(Register dst, const MemOperand& src, Condition cond = al);
+  void str(Register src, const MemOperand& dst, Condition cond = al);
+  void ldrb(Register dst, const MemOperand& src, Condition cond = al);
+  void strb(Register src, const MemOperand& dst, Condition cond = al);
+  void ldrh(Register dst, const MemOperand& src, Condition cond = al);
+  void strh(Register src, const MemOperand& dst, Condition cond = al);
+  void ldrsb(Register dst, const MemOperand& src, Condition cond = al);
+  void ldrsh(Register dst, const MemOperand& src, Condition cond = al);
+
+  // Load/Store multiple instructions
+  void ldm(BlockAddrMode am, Register base, RegList dst, Condition cond = al);
+  void stm(BlockAddrMode am, Register base, RegList src, Condition cond = al);
+
+  // Semaphore instructions
+  void swp(Register dst, Register src, Register base, Condition cond = al);
+  void swpb(Register dst, Register src, Register base, Condition cond = al);
+
+  // Exception-generating instructions and debugging support
+  void stop(const char* msg);
+
+  void bkpt(uint32_t imm16);  // v5 and above
+  void swi(uint32_t imm24, Condition cond = al);
+
+  // Coprocessor instructions
+
+  void cdp(Coprocessor coproc, int opcode_1,
+           CRegister crd, CRegister crn, CRegister crm,
+           int opcode_2, Condition cond = al);
+
+  void cdp2(Coprocessor coproc, int opcode_1,
+            CRegister crd, CRegister crn, CRegister crm,
+            int opcode_2);  // v5 and above
+
+  void mcr(Coprocessor coproc, int opcode_1,
+           Register rd, CRegister crn, CRegister crm,
+           int opcode_2 = 0, Condition cond = al);
+
+  void mcr2(Coprocessor coproc, int opcode_1,
+            Register rd, CRegister crn, CRegister crm,
+            int opcode_2 = 0);  // v5 and above
+
+  void mrc(Coprocessor coproc, int opcode_1,
+           Register rd, CRegister crn, CRegister crm,
+           int opcode_2 = 0, Condition cond = al);
+
+  void mrc2(Coprocessor coproc, int opcode_1,
+            Register rd, CRegister crn, CRegister crm,
+            int opcode_2 = 0);  // v5 and above
+
+  void ldc(Coprocessor coproc, CRegister crd, const MemOperand& src,
+           LFlag l = Short, Condition cond = al);
+  void ldc(Coprocessor coproc, CRegister crd, Register base, int option,
+           LFlag l = Short, Condition cond = al);
+
+  void ldc2(Coprocessor coproc, CRegister crd, const MemOperand& src,
+            LFlag l = Short);  // v5 and above
+  void ldc2(Coprocessor coproc, CRegister crd, Register base, int option,
+            LFlag l = Short);  // v5 and above
+
+  void stc(Coprocessor coproc, CRegister crd, const MemOperand& dst,
+           LFlag l = Short, Condition cond = al);
+  void stc(Coprocessor coproc, CRegister crd, Register base, int option,
+           LFlag l = Short, Condition cond = al);
+
+  void stc2(Coprocessor coproc, CRegister crd, const MemOperand& dst,
+            LFlag l = Short);  // v5 and above
+  void stc2(Coprocessor coproc, CRegister crd, Register base, int option,
+            LFlag l = Short);  // v5 and above
+
+  // Pseudo instructions
+  void nop()  { mov(r0, Operand(r0)); }
+
+  void push(Register src) {
+    str(src, MemOperand(sp, 4, NegPreIndex), al);
+  }
+
+  void pop(Register dst) {
+    ldr(dst, MemOperand(sp, 4, PostIndex), al);
+  }
+
+  void pop() {
+    add(sp, sp, Operand(kPointerSize));
+  }
+
+  // Load effective address of memory operand x into register dst
+  void lea(Register dst, const MemOperand& x,
+           SBit s = LeaveCC, Condition cond = al);
+
+  // Jump unconditionally to given label.
+  void jmp(Label* L) { b(L, al); }
+
+
+  // Debugging
+
+  // 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();
+
+  int pc_offset() const { return pc_ - buffer_; }
+  int current_position() const { return current_position_; }
+  int current_statement_position() const { return current_position_; }
+
+ protected:
+  int buffer_space() const { return reloc_info_writer.pos() - pc_; }
+
+  // Read/patch instructions
+  Instr instr_at(byte* pc) { return *reinterpret_cast<Instr*>(pc); }
+  void instr_at_put(byte* pc, Instr instr) {
+    *reinterpret_cast<Instr*>(pc) = instr;
+  }
+  Instr instr_at(int pos) { return *reinterpret_cast<Instr*>(buffer_ + pos); }
+  void instr_at_put(int pos, Instr instr) {
+    *reinterpret_cast<Instr*>(buffer_ + pos) = instr;
+  }
+
+  // Decode branch instruction at pos and return branch target pos
+  int target_at(int pos);
+
+  // Patch branch instruction at pos to branch to given branch target pos
+  void target_at_put(int pos, int target_pos);
+
+  // Check if is time to emit a constant pool for pending reloc info entries
+  void CheckConstPool(bool force_emit, bool require_jump);
+
+  // Block the emission of the constant pool before pc_offset
+  void BlockConstPoolBefore(int pc_offset) {
+    if (no_const_pool_before_ < pc_offset) no_const_pool_before_ = pc_offset;
+  }
+
+ private:
+  // 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_;
+
+  // Buffer size and constant pool distance are checked together at regular
+  // intervals of kBufferCheckInterval emitted bytes
+  static const int kBufferCheckInterval = 1*KB/2;
+  int next_buffer_check_;  // pc offset of next buffer check
+
+  // Code generation
+  static const int kInstrSize = sizeof(Instr);  // signed size
+  // The relocation writer's position is at least kGap bytes below the end of
+  // the generated instructions. This is so that multi-instruction sequences do
+  // not have to check for overflow. The same is true for writes of large
+  // relocation info entries.
+  static const int kGap = 32;
+  byte* pc_;  // the program counter; moves forward
+
+  // Constant pool generation
+  // Pools are emitted in the instruction stream, preferably after unconditional
+  // jumps or after returns from functions (in dead code locations).
+  // If a long code sequence does not contain unconditional jumps, it is
+  // necessary to emit the constant pool before the pool gets too far from the
+  // location it is accessed from. In this case, we emit a jump over the emitted
+  // constant pool.
+  // Constants in the pool may be addresses of functions that gets relocated;
+  // if so, a relocation info entry is associated to the constant pool entry.
+
+  // Repeated checking whether the constant pool should be emitted is rather
+  // expensive. By default we only check again once a number of instructions
+  // has been generated. That also means that the sizing of the buffers is not
+  // an exact science, and that we rely on some slop to not overrun buffers.
+  static const int kCheckConstIntervalInst = 32;
+  static const int kCheckConstInterval = kCheckConstIntervalInst * kInstrSize;
+
+
+  // Pools are emitted after function return and in dead code at (more or less)
+  // regular intervals of kDistBetweenPools bytes
+  static const int kDistBetweenPools = 1*KB;
+
+  // Constants in pools are accessed via pc relative addressing, which can
+  // reach +/-4KB thereby defining a maximum distance between the instruction
+  // and the accessed constant. We satisfy this constraint by limiting the
+  // distance between pools.
+  static const int kMaxDistBetweenPools = 4*KB - 2*kBufferCheckInterval;
+
+  // Emission of the constant pool may be blocked in some code sequences
+  int no_const_pool_before_;  // block emission before this pc offset
+
+  // Keep track of the last emitted pool to guarantee a maximal distance
+  int last_const_pool_end_;  // pc offset following the last constant pool
+
+  // Relocation info generation
+  // Each relocation is encoded as a variable size value
+  static const int kMaxRelocSize = RelocInfoWriter::kMaxSize;
+  RelocInfoWriter reloc_info_writer;
+  // Relocation info records are also used during code generation as temporary
+  // containers for constants and code target addresses until they are emitted
+  // to the constant pool. These pending relocation info records are temporarily
+  // stored in a separate buffer until a constant pool is emitted.
+  // If every instruction in a long sequence is accessing the pool, we need one
+  // pending relocation entry per instruction.
+  static const int kMaxNumPRInfo = kMaxDistBetweenPools/kInstrSize;
+  RelocInfo prinfo_[kMaxNumPRInfo];  // the buffer of pending relocation info
+  int num_prinfo_;  // number of pending reloc info entries in the buffer
+
+  // The bound position, before this we cannot do instruction elimination.
+  int last_bound_pos_;
+
+  // source position information
+  int current_position_;
+  int current_statement_position_;
+  int written_position_;
+  int written_statement_position_;
+
+  // Code emission
+  inline void CheckBuffer();
+  void GrowBuffer();
+  inline void emit(Instr x);
+
+  // Instruction generation
+  void addrmod1(Instr instr, Register rn, Register rd, const Operand& x);
+  void addrmod2(Instr instr, Register rd, const MemOperand& x);
+  void addrmod3(Instr instr, Register rd, const MemOperand& x);
+  void addrmod4(Instr instr, Register rn, RegList rl);
+  void addrmod5(Instr instr, CRegister crd, const MemOperand& x);
+
+  // Labels
+  void print(Label* L);
+  void bind_to(Label* L, int pos);
+  void link_to(Label* L, Label* appendix);
+  void next(Label* L);
+
+  // Record reloc info for current pc_
+  void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_ASSEMBLER_ARM_H_