Move backend specific files to separate directories.

src/arm/assembler-arm.cc

+// 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.
+
+#include "v8.h"
+
+#include "arm/assembler-arm-inl.h"
+#include "serialize.h"
+
+namespace v8 { namespace internal {
+
+// -----------------------------------------------------------------------------
+// Implementation of Register and CRegister
+
+Register no_reg = { -1 };
+
+Register r0  = {  0 };
+Register r1  = {  1 };
+Register r2  = {  2 };
+Register r3  = {  3 };
+Register r4  = {  4 };
+Register r5  = {  5 };
+Register r6  = {  6 };
+Register r7  = {  7 };
+Register r8  = {  8 };
+Register r9  = {  9 };
+Register r10 = { 10 };
+Register fp  = { 11 };
+Register ip  = { 12 };
+Register sp  = { 13 };
+Register lr  = { 14 };
+Register pc  = { 15 };
+
+
+CRegister no_creg = { -1 };
+
+CRegister cr0  = {  0 };
+CRegister cr1  = {  1 };
+CRegister cr2  = {  2 };
+CRegister cr3  = {  3 };
+CRegister cr4  = {  4 };
+CRegister cr5  = {  5 };
+CRegister cr6  = {  6 };
+CRegister cr7  = {  7 };
+CRegister cr8  = {  8 };
+CRegister cr9  = {  9 };
+CRegister cr10 = { 10 };
+CRegister cr11 = { 11 };
+CRegister cr12 = { 12 };
+CRegister cr13 = { 13 };
+CRegister cr14 = { 14 };
+CRegister cr15 = { 15 };
+
+
+// -----------------------------------------------------------------------------
+// Implementation of RelocInfo
+
+const int RelocInfo::kApplyMask = 0;
+
+
+void RelocInfo::PatchCode(byte* instructions, int instruction_count) {
+  // Patch the code at the current address with the supplied instructions.
+  UNIMPLEMENTED();
+}
+
+
+// Patch the code at the current PC with a call to the target address.
+// Additional guard instructions can be added if required.
+void RelocInfo::PatchCodeWithCall(Address target, int guard_bytes) {
+  // Patch the code at the current address with a call to the target.
+  UNIMPLEMENTED();
+}
+
+
+// -----------------------------------------------------------------------------
+// Implementation of Operand and MemOperand
+// See assembler-arm-inl.h for inlined constructors
+
+Operand::Operand(Handle<Object> handle) {
+  rm_ = no_reg;
+  // Verify all Objects referred by code are NOT in new space.
+  Object* obj = *handle;
+  ASSERT(!Heap::InNewSpace(obj));
+  if (obj->IsHeapObject()) {
+    imm32_ = reinterpret_cast<intptr_t>(handle.location());
+    rmode_ = RelocInfo::EMBEDDED_OBJECT;
+  } else {
+    // no relocation needed
+    imm32_ =  reinterpret_cast<intptr_t>(obj);
+    rmode_ = RelocInfo::NONE;
+  }
+}
+
+
+Operand::Operand(Register rm, ShiftOp shift_op, int shift_imm) {
+  ASSERT(is_uint5(shift_imm));
+  ASSERT(shift_op != ROR || shift_imm != 0);  // use RRX if you mean it
+  rm_ = rm;
+  rs_ = no_reg;
+  shift_op_ = shift_op;
+  shift_imm_ = shift_imm & 31;
+  if (shift_op == RRX) {
+    // encoded as ROR with shift_imm == 0
+    ASSERT(shift_imm == 0);
+    shift_op_ = ROR;
+    shift_imm_ = 0;
+  }
+}
+
+
+Operand::Operand(Register rm, ShiftOp shift_op, Register rs) {
+  ASSERT(shift_op != RRX);
+  rm_ = rm;
+  rs_ = no_reg;
+  shift_op_ = shift_op;
+  rs_ = rs;
+}
+
+
+MemOperand::MemOperand(Register rn, int32_t offset, AddrMode am) {
+  rn_ = rn;
+  rm_ = no_reg;
+  offset_ = offset;
+  am_ = am;
+}
+
+MemOperand::MemOperand(Register rn, Register rm, AddrMode am) {
+  rn_ = rn;
+  rm_ = rm;
+  shift_op_ = LSL;
+  shift_imm_ = 0;
+  am_ = am;
+}
+
+
+MemOperand::MemOperand(Register rn, Register rm,
+                       ShiftOp shift_op, int shift_imm, AddrMode am) {
+  ASSERT(is_uint5(shift_imm));
+  rn_ = rn;
+  rm_ = rm;
+  shift_op_ = shift_op;
+  shift_imm_ = shift_imm & 31;
+  am_ = am;
+}
+
+
+// -----------------------------------------------------------------------------
+// Implementation of Assembler
+
+// Instruction encoding bits
+enum {
+  H   = 1 << 5,   // halfword (or byte)
+  S6  = 1 << 6,   // signed (or unsigned)
+  L   = 1 << 20,  // load (or store)
+  S   = 1 << 20,  // set condition code (or leave unchanged)
+  W   = 1 << 21,  // writeback base register (or leave unchanged)
+  A   = 1 << 21,  // accumulate in multiply instruction (or not)
+  B   = 1 << 22,  // unsigned byte (or word)
+  N   = 1 << 22,  // long (or short)
+  U   = 1 << 23,  // positive (or negative) offset/index
+  P   = 1 << 24,  // offset/pre-indexed addressing (or post-indexed addressing)
+  I   = 1 << 25,  // immediate shifter operand (or not)
+
+  B4  = 1 << 4,
+  B5  = 1 << 5,
+  B7  = 1 << 7,
+  B8  = 1 << 8,
+  B12 = 1 << 12,
+  B16 = 1 << 16,
+  B20 = 1 << 20,
+  B21 = 1 << 21,
+  B22 = 1 << 22,
+  B23 = 1 << 23,
+  B24 = 1 << 24,
+  B25 = 1 << 25,
+  B26 = 1 << 26,
+  B27 = 1 << 27,
+
+  // Instruction bit masks
+  RdMask     = 15 << 12,  // in str instruction
+  CondMask   = 15 << 28,
+  OpCodeMask = 15 << 21,  // in data-processing instructions
+  Imm24Mask  = (1 << 24) - 1,
+  Off12Mask  = (1 << 12) - 1,
+  // Reserved condition
+  nv = 15 << 28
+};
+
+
+// add(sp, sp, 4) instruction (aka Pop())
+static const Instr kPopInstruction =
+    al | 4 * B21 | 4 | LeaveCC | I | sp.code() * B16 | sp.code() * B12;
+// str(r, MemOperand(sp, 4, NegPreIndex), al) instruction (aka push(r))
+// register r is not encoded.
+static const Instr kPushRegPattern =
+    al | B26 | 4 | NegPreIndex | sp.code() * B16;
+// ldr(r, MemOperand(sp, 4, PostIndex), al) instruction (aka pop(r))
+// register r is not encoded.
+static const Instr kPopRegPattern =
+    al | B26 | L | 4 | PostIndex | sp.code() * B16;
+
+// spare_buffer_
+static const int kMinimalBufferSize = 4*KB;
+static byte* spare_buffer_ = NULL;
+
+Assembler::Assembler(void* buffer, int buffer_size) {
+  if (buffer == NULL) {
+    // do our own buffer management
+    if (buffer_size <= kMinimalBufferSize) {
+      buffer_size = kMinimalBufferSize;
+
+      if (spare_buffer_ != NULL) {
+        buffer = spare_buffer_;
+        spare_buffer_ = NULL;
+      }
+    }
+    if (buffer == NULL) {
+      buffer_ = NewArray<byte>(buffer_size);
+    } else {
+      buffer_ = static_cast<byte*>(buffer);
+    }
+    buffer_size_ = buffer_size;
+    own_buffer_ = true;
+
+  } else {
+    // use externally provided buffer instead
+    ASSERT(buffer_size > 0);
+    buffer_ = static_cast<byte*>(buffer);
+    buffer_size_ = buffer_size;
+    own_buffer_ = false;
+  }
+
+  // setup buffer pointers
+  ASSERT(buffer_ != NULL);
+  pc_ = buffer_;
+  reloc_info_writer.Reposition(buffer_ + buffer_size, pc_);
+  num_prinfo_ = 0;
+  next_buffer_check_ = 0;
+  no_const_pool_before_ = 0;
+  last_const_pool_end_ = 0;
+  last_bound_pos_ = 0;
+  current_statement_position_ = RelocInfo::kNoPosition;
+  current_position_ = RelocInfo::kNoPosition;
+  written_statement_position_ = current_statement_position_;
+  written_position_ = current_position_;
+}
+
+
+Assembler::~Assembler() {
+  if (own_buffer_) {
+    if (spare_buffer_ == NULL && buffer_size_ == kMinimalBufferSize) {
+      spare_buffer_ = buffer_;
+    } else {
+      DeleteArray(buffer_);
+    }
+  }
+}
+
+
+void Assembler::GetCode(CodeDesc* desc) {
+  // emit constant pool if necessary
+  CheckConstPool(true, false);
+  ASSERT(num_prinfo_ == 0);
+
+  // setup desc
+  desc->buffer = buffer_;
+  desc->buffer_size = buffer_size_;
+  desc->instr_size = pc_offset();
+  desc->reloc_size = (buffer_ + buffer_size_) - reloc_info_writer.pos();
+}
+
+
+void Assembler::Align(int m) {
+  ASSERT(m >= 4 && IsPowerOf2(m));
+  while ((pc_offset() & (m - 1)) != 0) {
+    nop();
+  }
+}
+
+
+// Labels refer to positions in the (to be) generated code.
+// There are bound, linked, and unused labels.
+//
+// Bound labels refer to known positions in the already
+// generated code. pos() is the position the label refers to.
+//
+// Linked labels refer to unknown positions in the code
+// to be generated; pos() is the position of the last
+// instruction using the label.
+
+
+// The link chain is terminated by a negative code position (must be aligned)
+const int kEndOfChain = -4;
+
+
+int Assembler::target_at(int pos)  {
+  Instr instr = instr_at(pos);
+  ASSERT((instr & 7*B25) == 5*B25);  // b, bl, or blx imm24
+  int imm26 = ((instr & Imm24Mask) << 8) >> 6;
+  if ((instr & CondMask) == nv && (instr & B24) != 0)
+    // blx uses bit 24 to encode bit 2 of imm26
+    imm26 += 2;
+
+  return pos + 8 + imm26;
+}
+
+
+void Assembler::target_at_put(int pos, int target_pos) {
+  int imm26 = target_pos - pos - 8;
+  Instr instr = instr_at(pos);
+  ASSERT((instr & 7*B25) == 5*B25);  // b, bl, or blx imm24
+  if ((instr & CondMask) == nv) {
+    // blx uses bit 24 to encode bit 2 of imm26
+    ASSERT((imm26 & 1) == 0);
+    instr = (instr & ~(B24 | Imm24Mask)) | ((imm26 & 2) >> 1)*B24;
+  } else {
+    ASSERT((imm26 & 3) == 0);
+    instr &= ~Imm24Mask;
+  }
+  int imm24 = imm26 >> 2;
+  ASSERT(is_int24(imm24));
+  instr_at_put(pos, instr | (imm24 & Imm24Mask));
+}
+
+
+void Assembler::print(Label* L) {
+  if (L->is_unused()) {
+    PrintF("unused label\n");
+  } else if (L->is_bound()) {
+    PrintF("bound label to %d\n", L->pos());
+  } else if (L->is_linked()) {
+    Label l = *L;
+    PrintF("unbound label");
+    while (l.is_linked()) {
+      PrintF("@ %d ", l.pos());
+      Instr instr = instr_at(l.pos());
+      ASSERT((instr & 7*B25) == 5*B25);  // b, bl, or blx
+      int cond = instr & CondMask;
+      const char* b;
+      const char* c;
+      if (cond == nv) {
+        b = "blx";
+        c = "";
+      } else {
+        if ((instr & B24) != 0)
+          b = "bl";
+        else
+          b = "b";
+
+        switch (cond) {
+          case eq: c = "eq"; break;
+          case ne: c = "ne"; break;
+          case hs: c = "hs"; break;
+          case lo: c = "lo"; break;
+          case mi: c = "mi"; break;
+          case pl: c = "pl"; break;
+          case vs: c = "vs"; break;
+          case vc: c = "vc"; break;
+          case hi: c = "hi"; break;
+          case ls: c = "ls"; break;
+          case ge: c = "ge"; break;
+          case lt: c = "lt"; break;
+          case gt: c = "gt"; break;
+          case le: c = "le"; break;
+          case al: c = ""; break;
+          default:
+            c = "";
+            UNREACHABLE();
+        }
+      }
+      PrintF("%s%s\n", b, c);
+      next(&l);
+    }
+  } else {
+    PrintF("label in inconsistent state (pos = %d)\n", L->pos_);
+  }
+}
+
+
+void Assembler::bind_to(Label* L, int pos) {
+  ASSERT(0 <= pos && pos <= pc_offset());  // must have a valid binding position
+  while (L->is_linked()) {
+    int fixup_pos = L->pos();
+    next(L);  // call next before overwriting link with target at fixup_pos
+    target_at_put(fixup_pos, pos);
+  }
+  L->bind_to(pos);
+
+  // Keep track of the last bound label so we don't eliminate any instructions
+  // before a bound label.
+  if (pos > last_bound_pos_)
+    last_bound_pos_ = pos;
+}
+
+
+void Assembler::link_to(Label* L, Label* appendix) {
+  if (appendix->is_linked()) {
+    if (L->is_linked()) {
+      // append appendix to L's list
+      int fixup_pos;
+      int link = L->pos();
+      do {
+        fixup_pos = link;
+        link = target_at(fixup_pos);
+      } while (link > 0);
+      ASSERT(link == kEndOfChain);
+      target_at_put(fixup_pos, appendix->pos());
+    } else {
+      // L is empty, simply use appendix
+      *L = *appendix;
+    }
+  }
+  appendix->Unuse();  // appendix should not be used anymore
+}
+
+
+void Assembler::bind(Label* L) {
+  ASSERT(!L->is_bound());  // label can only be bound once
+  bind_to(L, pc_offset());
+}
+
+
+void Assembler::next(Label* L) {
+  ASSERT(L->is_linked());
+  int link = target_at(L->pos());
+  if (link > 0) {
+    L->link_to(link);
+  } else {
+    ASSERT(link == kEndOfChain);
+    L->Unuse();
+  }
+}
+
+
+// Low-level code emission routines depending on the addressing mode
+static bool fits_shifter(uint32_t imm32,
+                         uint32_t* rotate_imm,
+                         uint32_t* immed_8,
+                         Instr* instr) {
+  // imm32 must be unsigned
+  for (int rot = 0; rot < 16; rot++) {
+    uint32_t imm8 = (imm32 << 2*rot) | (imm32 >> (32 - 2*rot));
+    if ((imm8 <= 0xff)) {
+      *rotate_imm = rot;
+      *immed_8 = imm8;
+      return true;
+    }
+  }
+  // if the opcode is mov or mvn and if ~imm32 fits, change the opcode
+  if (instr != NULL && (*instr & 0xd*B21) == 0xd*B21) {
+    if (fits_shifter(~imm32, rotate_imm, immed_8, NULL)) {
+      *instr ^= 0x2*B21;
+      return true;
+    }
+  }
+  return false;
+}
+
+
+void Assembler::addrmod1(Instr instr,
+                         Register rn,
+                         Register rd,
+                         const Operand& x) {
+  CheckBuffer();
+  ASSERT((instr & ~(CondMask | OpCodeMask | S)) == 0);
+  if (!x.rm_.is_valid()) {
+    // immediate
+    uint32_t rotate_imm;
+    uint32_t immed_8;
+    if ((x.rmode_ != RelocInfo::NONE &&
+         x.rmode_ != RelocInfo::EXTERNAL_REFERENCE) ||
+        !fits_shifter(x.imm32_, &rotate_imm, &immed_8, &instr)) {
+      // The immediate operand cannot be encoded as a shifter operand, so load
+      // it first to register ip and change the original instruction to use ip.
+      // However, if the original instruction is a 'mov rd, x' (not setting the
+      // condition code), then replace it with a 'ldr rd, [pc]'
+      RecordRelocInfo(x.rmode_, x.imm32_);
+      CHECK(!rn.is(ip));  // rn should never be ip, or will be trashed
+      Condition cond = static_cast<Condition>(instr & CondMask);
+      if ((instr & ~CondMask) == 13*B21) {  // mov, S not set
+        ldr(rd, MemOperand(pc, 0), cond);
+      } else {
+        ldr(ip, MemOperand(pc, 0), cond);
+        addrmod1(instr, rn, rd, Operand(ip));
+      }
+      return;
+    }
+    instr |= I | rotate_imm*B8 | immed_8;
+  } else if (!x.rs_.is_valid()) {
+    // immediate shift
+    instr |= x.shift_imm_*B7 | x.shift_op_ | x.rm_.code();
+  } else {
+    // register shift
+    ASSERT(!rn.is(pc) && !rd.is(pc) && !x.rm_.is(pc) && !x.rs_.is(pc));
+    instr |= x.rs_.code()*B8 | x.shift_op_ | B4 | x.rm_.code();
+  }
+  emit(instr | rn.code()*B16 | rd.code()*B12);
+  if (rn.is(pc) || x.rm_.is(pc))
+    // block constant pool emission for one instruction after reading pc
+    BlockConstPoolBefore(pc_offset() + kInstrSize);
+}
+
+
+void Assembler::addrmod2(Instr instr, Register rd, const MemOperand& x) {
+  ASSERT((instr & ~(CondMask | B | L)) == B26);
+  int am = x.am_;
+  if (!x.rm_.is_valid()) {
+    // immediate offset
+    int offset_12 = x.offset_;
+    if (offset_12 < 0) {
+      offset_12 = -offset_12;
+      am ^= U;
+    }
+    if (!is_uint12(offset_12)) {
+      // immediate offset cannot be encoded, load it first to register ip
+      // rn (and rd in a load) should never be ip, or will be trashed
+      ASSERT(!x.rn_.is(ip) && ((instr & L) == L || !rd.is(ip)));
+      mov(ip, Operand(x.offset_), LeaveCC,
+          static_cast<Condition>(instr & CondMask));
+      addrmod2(instr, rd, MemOperand(x.rn_, ip, x.am_));
+      return;
+    }
+    ASSERT(offset_12 >= 0);  // no masking needed
+    instr |= offset_12;
+  } else {
+    // register offset (shift_imm_ and shift_op_ are 0) or scaled
+    // register offset the constructors make sure than both shift_imm_
+    // and shift_op_ are initialized
+    ASSERT(!x.rm_.is(pc));
+    instr |= B25 | x.shift_imm_*B7 | x.shift_op_ | x.rm_.code();
+  }
+  ASSERT((am & (P|W)) == P || !x.rn_.is(pc));  // no pc base with writeback
+  emit(instr | am | x.rn_.code()*B16 | rd.code()*B12);
+}
+
+
+void Assembler::addrmod3(Instr instr, Register rd, const MemOperand& x) {
+  ASSERT((instr & ~(CondMask | L | S6 | H)) == (B4 | B7));
+  ASSERT(x.rn_.is_valid());
+  int am = x.am_;
+  if (!x.rm_.is_valid()) {
+    // immediate offset
+    int offset_8 = x.offset_;
+    if (offset_8 < 0) {
+      offset_8 = -offset_8;
+      am ^= U;
+    }
+    if (!is_uint8(offset_8)) {
+      // immediate offset cannot be encoded, load it first to register ip
+      // rn (and rd in a load) should never be ip, or will be trashed
+      ASSERT(!x.rn_.is(ip) && ((instr & L) == L || !rd.is(ip)));
+      mov(ip, Operand(x.offset_), LeaveCC,
+          static_cast<Condition>(instr & CondMask));
+      addrmod3(instr, rd, MemOperand(x.rn_, ip, x.am_));
+      return;
+    }
+    ASSERT(offset_8 >= 0);  // no masking needed
+    instr |= B | (offset_8 >> 4)*B8 | (offset_8 & 0xf);
+  } else if (x.shift_imm_ != 0) {
+    // scaled register offset not supported, load index first
+    // rn (and rd in a load) should never be ip, or will be trashed
+    ASSERT(!x.rn_.is(ip) && ((instr & L) == L || !rd.is(ip)));
+    mov(ip, Operand(x.rm_, x.shift_op_, x.shift_imm_), LeaveCC,
+        static_cast<Condition>(instr & CondMask));
+    addrmod3(instr, rd, MemOperand(x.rn_, ip, x.am_));
+    return;
+  } else {
+    // register offset
+    ASSERT((am & (P|W)) == P || !x.rm_.is(pc));  // no pc index with writeback
+    instr |= x.rm_.code();
+  }
+  ASSERT((am & (P|W)) == P || !x.rn_.is(pc));  // no pc base with writeback
+  emit(instr | am | x.rn_.code()*B16 | rd.code()*B12);
+}
+
+
+void Assembler::addrmod4(Instr instr, Register rn, RegList rl) {
+  ASSERT((instr & ~(CondMask | P | U | W | L)) == B27);
+  ASSERT(rl != 0);
+  ASSERT(!rn.is(pc));
+  emit(instr | rn.code()*B16 | rl);
+}
+
+
+void Assembler::addrmod5(Instr instr, CRegister crd, const MemOperand& x) {
+  // unindexed addressing is not encoded by this function
+  ASSERT((instr & ~(CondMask | P | U | N | W | L)) == (B27 | B26));
+  ASSERT(x.rn_.is_valid() && !x.rm_.is_valid());
+  int am = x.am_;
+  int offset_8 = x.offset_;
+  ASSERT((offset_8 & 3) == 0);  // offset must be an aligned word offset
+  offset_8 >>= 2;
+  if (offset_8 < 0) {
+    offset_8 = -offset_8;
+    am ^= U;
+  }
+  ASSERT(is_uint8(offset_8));  // unsigned word offset must fit in a byte
+  ASSERT((am & (P|W)) == P || !x.rn_.is(pc));  // no pc base with writeback
+
+  // post-indexed addressing requires W == 1; different than in addrmod2/3
+  if ((am & P) == 0)
+    am |= W;
+
+  ASSERT(offset_8 >= 0);  // no masking needed
+  emit(instr | am | x.rn_.code()*B16 | crd.code()*B12 | offset_8);
+}
+
+
+int Assembler::branch_offset(Label* L, bool jump_elimination_allowed) {
+  int target_pos;
+  if (L->is_bound()) {
+    target_pos = L->pos();
+  } else {
+    if (L->is_linked()) {
+      target_pos = L->pos();  // L's link
+    } else {
+      target_pos = kEndOfChain;
+    }
+    L->link_to(pc_offset());
+  }
+
+  // Block the emission of the constant pool, since the branch instruction must
+  // be emitted at the pc offset recorded by the label
+  BlockConstPoolBefore(pc_offset() + kInstrSize);
+
+  return target_pos - pc_offset() - 8;
+}
+
+
+// Branch instructions
+void Assembler::b(int branch_offset, Condition cond) {
+  ASSERT((branch_offset & 3) == 0);
+  int imm24 = branch_offset >> 2;
+  ASSERT(is_int24(imm24));
+  emit(cond | B27 | B25 | (imm24 & Imm24Mask));
+
+  if (cond == al)
+    // dead code is a good location to emit the constant pool
+    CheckConstPool(false, false);
+}
+
+
+void Assembler::bl(int branch_offset, Condition cond) {
+  ASSERT((branch_offset & 3) == 0);
+  int imm24 = branch_offset >> 2;
+  ASSERT(is_int24(imm24));
+  emit(cond | B27 | B25 | B24 | (imm24 & Imm24Mask));
+}
+
+
+void Assembler::blx(int branch_offset) {  // v5 and above
+  ASSERT((branch_offset & 1) == 0);
+  int h = ((branch_offset & 2) >> 1)*B24;
+  int imm24 = branch_offset >> 2;
+  ASSERT(is_int24(imm24));
+  emit(15 << 28 | B27 | B25 | h | (imm24 & Imm24Mask));
+}
+
+
+void Assembler::blx(Register target, Condition cond) {  // v5 and above
+  ASSERT(!target.is(pc));
+  emit(cond | B24 | B21 | 15*B16 | 15*B12 | 15*B8 | 3*B4 | target.code());
+}
+
+
+void Assembler::bx(Register target, Condition cond) {  // v5 and above, plus v4t
+  ASSERT(!target.is(pc));  // use of pc is actually allowed, but discouraged
+  emit(cond | B24 | B21 | 15*B16 | 15*B12 | 15*B8 | B4 | target.code());
+}
+
+
+// Data-processing instructions
+void Assembler::and_(Register dst, Register src1, const Operand& src2,
+                     SBit s, Condition cond) {
+  addrmod1(cond | 0*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::eor(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 1*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::sub(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 2*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::rsb(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 3*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::add(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 4*B21 | s, src1, dst, src2);
+
+  // Eliminate pattern: push(r), pop()
+  //   str(src, MemOperand(sp, 4, NegPreIndex), al);
+  //   add(sp, sp, Operand(kPointerSize));
+  // Both instructions can be eliminated.
+  int pattern_size = 2 * kInstrSize;
+  if (FLAG_push_pop_elimination &&
+      last_bound_pos_ <= (pc_offset() - pattern_size) &&
+      reloc_info_writer.last_pc() <= (pc_ - pattern_size) &&
+      // pattern
+      instr_at(pc_ - 1 * kInstrSize) == kPopInstruction &&
+      (instr_at(pc_ - 2 * kInstrSize) & ~RdMask) == kPushRegPattern) {
+    pc_ -= 2 * kInstrSize;
+    if (FLAG_print_push_pop_elimination) {
+      PrintF("%x push(reg)/pop() eliminated\n", pc_offset());
+    }
+  }
+}
+
+
+void Assembler::adc(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 5*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::sbc(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 6*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::rsc(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 7*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::tst(Register src1, const Operand& src2, Condition cond) {
+  addrmod1(cond | 8*B21 | S, src1, r0, src2);
+}
+
+
+void Assembler::teq(Register src1, const Operand& src2, Condition cond) {
+  addrmod1(cond | 9*B21 | S, src1, r0, src2);
+}
+
+
+void Assembler::cmp(Register src1, const Operand& src2, Condition cond) {
+  addrmod1(cond | 10*B21 | S, src1, r0, src2);
+}
+
+
+void Assembler::cmn(Register src1, const Operand& src2, Condition cond) {
+  addrmod1(cond | 11*B21 | S, src1, r0, src2);
+}
+
+
+void Assembler::orr(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 12*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::mov(Register dst, const Operand& src, SBit s, Condition cond) {
+  addrmod1(cond | 13*B21 | s, r0, dst, src);
+}
+
+
+void Assembler::bic(Register dst, Register src1, const Operand& src2,
+                    SBit s, Condition cond) {
+  addrmod1(cond | 14*B21 | s, src1, dst, src2);
+}
+
+
+void Assembler::mvn(Register dst, const Operand& src, SBit s, Condition cond) {
+  addrmod1(cond | 15*B21 | s, r0, dst, src);
+}
+
+
+// Multiply instructions
+void Assembler::mla(Register dst, Register src1, Register src2, Register srcA,
+                    SBit s, Condition cond) {
+  ASSERT(!dst.is(pc) && !src1.is(pc) && !src2.is(pc) && !srcA.is(pc));
+  ASSERT(!dst.is(src1));
+  emit(cond | A | s | dst.code()*B16 | srcA.code()*B12 |
+       src2.code()*B8 | B7 | B4 | src1.code());
+}
+
+
+void Assembler::mul(Register dst, Register src1, Register src2,
+                    SBit s, Condition cond) {
+  ASSERT(!dst.is(pc) && !src1.is(pc) && !src2.is(pc));
+  ASSERT(!dst.is(src1));
+  emit(cond | s | dst.code()*B16 | src2.code()*B8 | B7 | B4 | src1.code());
+}
+
+
+void Assembler::smlal(Register dstL,
+                      Register dstH,
+                      Register src1,
+                      Register src2,
+                      SBit s,
+                      Condition cond) {
+  ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
+  ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
+  emit(cond | B23 | B22 | A | s | dstH.code()*B16 | dstL.code()*B12 |
+       src2.code()*B8 | B7 | B4 | src1.code());
+}
+
+
+void Assembler::smull(Register dstL,
+                      Register dstH,
+                      Register src1,
+                      Register src2,
+                      SBit s,
+                      Condition cond) {
+  ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
+  ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
+  emit(cond | B23 | B22 | s | dstH.code()*B16 | dstL.code()*B12 |
+       src2.code()*B8 | B7 | B4 | src1.code());
+}
+
+
+void Assembler::umlal(Register dstL,
+                      Register dstH,
+                      Register src1,
+                      Register src2,
+                      SBit s,
+                      Condition cond) {
+  ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
+  ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
+  emit(cond | B23 | A | s | dstH.code()*B16 | dstL.code()*B12 |
+       src2.code()*B8 | B7 | B4 | src1.code());
+}
+
+
+void Assembler::umull(Register dstL,
+                      Register dstH,
+                      Register src1,
+                      Register src2,
+                      SBit s,
+                      Condition cond) {
+  ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
+  ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
+  emit(cond | B23 | s | dstH.code()*B16 | dstL.code()*B12 |
+       src2.code()*B8 | B7 | B4 | src1.code());
+}
+
+
+// Miscellaneous arithmetic instructions
+void Assembler::clz(Register dst, Register src, Condition cond) {
+  // v5 and above.
+  ASSERT(!dst.is(pc) && !src.is(pc));
+  emit(cond | B24 | B22 | B21 | 15*B16 | dst.code()*B12 |
+       15*B8 | B4 | src.code());
+}
+
+
+// Status register access instructions
+void Assembler::mrs(Register dst, SRegister s, Condition cond) {
+  ASSERT(!dst.is(pc));
+  emit(cond | B24 | s | 15*B16 | dst.code()*B12);
+}
+
+
+void Assembler::msr(SRegisterFieldMask fields, const Operand& src,
+                    Condition cond) {
+  ASSERT(fields >= B16 && fields < B20);  // at least one field set
+  Instr instr;
+  if (!src.rm_.is_valid()) {
+    // immediate
+    uint32_t rotate_imm;
+    uint32_t immed_8;
+    if ((src.rmode_ != RelocInfo::NONE &&
+         src.rmode_ != RelocInfo::EXTERNAL_REFERENCE)||
+        !fits_shifter(src.imm32_, &rotate_imm, &immed_8, NULL)) {
+      // immediate operand cannot be encoded, load it first to register ip
+      RecordRelocInfo(src.rmode_, src.imm32_);
+      ldr(ip, MemOperand(pc, 0), cond);
+      msr(fields, Operand(ip), cond);
+      return;
+    }
+    instr = I | rotate_imm*B8 | immed_8;
+  } else {
+    ASSERT(!src.rs_.is_valid() && src.shift_imm_ == 0);  // only rm allowed
+    instr = src.rm_.code();
+  }
+  emit(cond | instr | B24 | B21 | fields | 15*B12);
+}
+
+
+// Load/Store instructions
+void Assembler::ldr(Register dst, const MemOperand& src, Condition cond) {
+  addrmod2(cond | B26 | L, dst, src);
+
+  // Eliminate pattern: push(r), pop(r)
+  //   str(r, MemOperand(sp, 4, NegPreIndex), al)
+  //   ldr(r, MemOperand(sp, 4, PostIndex), al)
+  // Both instructions can be eliminated.
+  int pattern_size = 2 * kInstrSize;
+  if (FLAG_push_pop_elimination &&
+      last_bound_pos_ <= (pc_offset() - pattern_size) &&
+      reloc_info_writer.last_pc() <= (pc_ - pattern_size) &&
+      // pattern
+      instr_at(pc_ - 1 * kInstrSize) == (kPopRegPattern | dst.code() * B12) &&
+      instr_at(pc_ - 2 * kInstrSize) == (kPushRegPattern | dst.code() * B12)) {
+    pc_ -= 2 * kInstrSize;
+    if (FLAG_print_push_pop_elimination) {
+      PrintF("%x push/pop (same reg) eliminated\n", pc_offset());
+    }
+  }
+}
+
+
+void Assembler::str(Register src, const MemOperand& dst, Condition cond) {
+  addrmod2(cond | B26, src, dst);
+
+  // Eliminate pattern: pop(), push(r)
+  //     add sp, sp, #4 LeaveCC, al; str r, [sp, #-4], al
+  // ->  str r, [sp, 0], al
+  int pattern_size = 2 * kInstrSize;
+  if (FLAG_push_pop_elimination &&
+     last_bound_pos_ <= (pc_offset() - pattern_size) &&
+     reloc_info_writer.last_pc() <= (pc_ - pattern_size) &&
+     instr_at(pc_ - 1 * kInstrSize) == (kPushRegPattern | src.code() * B12) &&
+     instr_at(pc_ - 2 * kInstrSize) == kPopInstruction) {
+    pc_ -= 2 * kInstrSize;
+    emit(al | B26 | 0 | Offset | sp.code() * B16 | src.code() * B12);
+    if (FLAG_print_push_pop_elimination) {
+      PrintF("%x pop()/push(reg) eliminated\n", pc_offset());
+    }
+  }
+}
+
+
+void Assembler::ldrb(Register dst, const MemOperand& src, Condition cond) {
+  addrmod2(cond | B26 | B | L, dst, src);
+}
+
+
+void Assembler::strb(Register src, const MemOperand& dst, Condition cond) {
+  addrmod2(cond | B26 | B, src, dst);
+}
+
+
+void Assembler::ldrh(Register dst, const MemOperand& src, Condition cond) {
+  addrmod3(cond | L | B7 | H | B4, dst, src);
+}
+
+
+void Assembler::strh(Register src, const MemOperand& dst, Condition cond) {
+  addrmod3(cond | B7 | H | B4, src, dst);
+}
+
+
+void Assembler::ldrsb(Register dst, const MemOperand& src, Condition cond) {
+  addrmod3(cond | L | B7 | S6 | B4, dst, src);
+}
+
+
+void Assembler::ldrsh(Register dst, const MemOperand& src, Condition cond) {
+  addrmod3(cond | L | B7 | S6 | H | B4, dst, src);
+}
+
+
+// Load/Store multiple instructions
+void Assembler::ldm(BlockAddrMode am,
+                    Register base,
+                    RegList dst,
+                    Condition cond) {
+  // ABI stack constraint: ldmxx base, {..sp..}  base != sp  is not restartable
+  ASSERT(base.is(sp) || (dst & sp.bit()) == 0);
+
+  addrmod4(cond | B27 | am | L, base, dst);
+
+  // emit the constant pool after a function return implemented by ldm ..{..pc}
+  if (cond == al && (dst & pc.bit()) != 0) {
+    // There is a slight chance that the ldm instruction was actually a call,
+    // in which case it would be wrong to return into the constant pool; we
+    // recognize this case by checking if the emission of the pool was blocked
+    // at the pc of the ldm instruction by a mov lr, pc instruction; if this is
+    // the case, we emit a jump over the pool.
+    CheckConstPool(true, no_const_pool_before_ == pc_offset() - kInstrSize);
+  }
+}
+
+
+void Assembler::stm(BlockAddrMode am,
+                    Register base,
+                    RegList src,
+                    Condition cond) {
+  addrmod4(cond | B27 | am, base, src);
+}
+
+
+// Semaphore instructions
+void Assembler::swp(Register dst, Register src, Register base, Condition cond) {
+  ASSERT(!dst.is(pc) && !src.is(pc) && !base.is(pc));
+  ASSERT(!dst.is(base) && !src.is(base));
+  emit(cond | P | base.code()*B16 | dst.code()*B12 |
+       B7 | B4 | src.code());
+}
+
+
+void Assembler::swpb(Register dst,
+                     Register src,
+                     Register base,
+                     Condition cond) {
+  ASSERT(!dst.is(pc) && !src.is(pc) && !base.is(pc));
+  ASSERT(!dst.is(base) && !src.is(base));
+  emit(cond | P | B | base.code()*B16 | dst.code()*B12 |
+       B7 | B4 | src.code());
+}
+
+
+// Exception-generating instructions and debugging support
+void Assembler::stop(const char* msg) {
+#if !defined(__arm__)
+  // The simulator handles these special instructions and stops execution.
+  emit(15 << 28 | ((intptr_t) msg));
+#else
+  // Just issue a simple break instruction for now. Alternatively we could use
+  // the swi(0x9f0001) instruction on Linux.
+  bkpt(0);
+#endif
+}
+
+
+void Assembler::bkpt(uint32_t imm16) {  // v5 and above
+  ASSERT(is_uint16(imm16));
+  emit(al | B24 | B21 | (imm16 >> 4)*B8 | 7*B4 | (imm16 & 0xf));
+}
+
+
+void Assembler::swi(uint32_t imm24, Condition cond) {
+  ASSERT(is_uint24(imm24));
+  emit(cond | 15*B24 | imm24);
+}
+
+
+// Coprocessor instructions
+void Assembler::cdp(Coprocessor coproc,
+                    int opcode_1,
+                    CRegister crd,
+                    CRegister crn,
+                    CRegister crm,
+                    int opcode_2,
+                    Condition cond) {
+  ASSERT(is_uint4(opcode_1) && is_uint3(opcode_2));
+  emit(cond | B27 | B26 | B25 | (opcode_1 & 15)*B20 | crn.code()*B16 |
+       crd.code()*B12 | coproc*B8 | (opcode_2 & 7)*B5 | crm.code());
+}
+
+
+void Assembler::cdp2(Coprocessor coproc,
+                     int opcode_1,
+                     CRegister crd,
+                     CRegister crn,
+                     CRegister crm,
+                     int opcode_2) {  // v5 and above
+  cdp(coproc, opcode_1, crd, crn, crm, opcode_2, static_cast<Condition>(nv));
+}
+
+
+void Assembler::mcr(Coprocessor coproc,
+                    int opcode_1,
+                    Register rd,
+                    CRegister crn,
+                    CRegister crm,
+                    int opcode_2,
+                    Condition cond) {
+  ASSERT(is_uint3(opcode_1) && is_uint3(opcode_2));
+  emit(cond | B27 | B26 | B25 | (opcode_1 & 7)*B21 | crn.code()*B16 |
+       rd.code()*B12 | coproc*B8 | (opcode_2 & 7)*B5 | B4 | crm.code());
+}
+
+
+void Assembler::mcr2(Coprocessor coproc,
+                     int opcode_1,
+                     Register rd,
+                     CRegister crn,
+                     CRegister crm,
+                     int opcode_2) {  // v5 and above
+  mcr(coproc, opcode_1, rd, crn, crm, opcode_2, static_cast<Condition>(nv));
+}
+
+
+void Assembler::mrc(Coprocessor coproc,
+                    int opcode_1,
+                    Register rd,
+                    CRegister crn,
+                    CRegister crm,
+                    int opcode_2,
+                    Condition cond) {
+  ASSERT(is_uint3(opcode_1) && is_uint3(opcode_2));
+  emit(cond | B27 | B26 | B25 | (opcode_1 & 7)*B21 | L | crn.code()*B16 |
+       rd.code()*B12 | coproc*B8 | (opcode_2 & 7)*B5 | B4 | crm.code());
+}
+
+
+void Assembler::mrc2(Coprocessor coproc,
+                     int opcode_1,
+                     Register rd,
+                     CRegister crn,
+                     CRegister crm,
+                     int opcode_2) {  // v5 and above
+  mrc(coproc, opcode_1, rd, crn, crm, opcode_2, static_cast<Condition>(nv));
+}
+
+
+void Assembler::ldc(Coprocessor coproc,
+                    CRegister crd,
+                    const MemOperand& src,
+                    LFlag l,
+                    Condition cond) {
+  addrmod5(cond | B27 | B26 | l | L | coproc*B8, crd, src);
+}
+
+
+void Assembler::ldc(Coprocessor coproc,
+                    CRegister crd,
+                    Register rn,
+                    int option,
+                    LFlag l,
+                    Condition cond) {
+  // unindexed addressing
+  ASSERT(is_uint8(option));
+  emit(cond | B27 | B26 | U | l | L | rn.code()*B16 | crd.code()*B12 |
+       coproc*B8 | (option & 255));
+}
+
+
+void Assembler::ldc2(Coprocessor coproc,
+                     CRegister crd,
+                     const MemOperand& src,
+                     LFlag l) {  // v5 and above
+  ldc(coproc, crd, src, l, static_cast<Condition>(nv));
+}
+
+
+void Assembler::ldc2(Coprocessor coproc,
+                     CRegister crd,
+                     Register rn,
+                     int option,
+                     LFlag l) {  // v5 and above
+  ldc(coproc, crd, rn, option, l, static_cast<Condition>(nv));
+}
+
+
+void Assembler::stc(Coprocessor coproc,
+                    CRegister crd,
+                    const MemOperand& dst,
+                    LFlag l,
+                    Condition cond) {
+  addrmod5(cond | B27 | B26 | l | coproc*B8, crd, dst);
+}
+
+
+void Assembler::stc(Coprocessor coproc,
+                    CRegister crd,
+                    Register rn,
+                    int option,
+                    LFlag l,
+                    Condition cond) {
+  // unindexed addressing
+  ASSERT(is_uint8(option));
+  emit(cond | B27 | B26 | U | l | rn.code()*B16 | crd.code()*B12 |
+       coproc*B8 | (option & 255));
+}
+
+
+void Assembler::stc2(Coprocessor
+                     coproc, CRegister crd,
+                     const MemOperand& dst,
+                     LFlag l) {  // v5 and above
+  stc(coproc, crd, dst, l, static_cast<Condition>(nv));
+}
+
+
+void Assembler::stc2(Coprocessor coproc,
+                     CRegister crd,
+                     Register rn,
+                     int option,
+                     LFlag l) {  // v5 and above
+  stc(coproc, crd, rn, option, l, static_cast<Condition>(nv));
+}
+
+
+// Pseudo instructions
+void Assembler::lea(Register dst,
+                    const MemOperand& x,
+                    SBit s,
+                    Condition cond) {
+  int am = x.am_;
+  if (!x.rm_.is_valid()) {
+    // immediate offset
+    if ((am & P) == 0)  // post indexing
+      mov(dst, Operand(x.rn_), s, cond);
+    else if ((am & U) == 0)  // negative indexing
+      sub(dst, x.rn_, Operand(x.offset_), s, cond);
+    else
+      add(dst, x.rn_, Operand(x.offset_), s, cond);
+  } else {
+    // Register offset (shift_imm_ and shift_op_ are 0) or scaled
+    // register offset the constructors make sure than both shift_imm_
+    // and shift_op_ are initialized.
+    ASSERT(!x.rm_.is(pc));
+    if ((am & P) == 0)  // post indexing
+      mov(dst, Operand(x.rn_), s, cond);
+    else if ((am & U) == 0)  // negative indexing
+      sub(dst, x.rn_, Operand(x.rm_, x.shift_op_, x.shift_imm_), s, cond);
+    else
+      add(dst, x.rn_, Operand(x.rm_, x.shift_op_, x.shift_imm_), s, cond);
+  }
+}
+
+
+// Debugging
+void Assembler::RecordComment(const char* msg) {
+  if (FLAG_debug_code) {
+    CheckBuffer();
+    RecordRelocInfo(RelocInfo::COMMENT, reinterpret_cast<intptr_t>(msg));
+  }
+}
+
+
+void Assembler::RecordPosition(int pos) {
+  if (pos == RelocInfo::kNoPosition) return;
+  ASSERT(pos >= 0);
+  current_position_ = pos;
+  WriteRecordedPositions();
+}
+
+
+void Assembler::RecordStatementPosition(int pos) {
+  if (pos == RelocInfo::kNoPosition) return;
+  ASSERT(pos >= 0);
+  current_statement_position_ = pos;
+  WriteRecordedPositions();
+}
+
+
+void Assembler::WriteRecordedPositions() {
+  // Write the statement position if it is different from what was written last
+  // time.
+  if (current_statement_position_ != written_statement_position_) {
+    CheckBuffer();
+    RecordRelocInfo(RelocInfo::STATEMENT_POSITION, current_statement_position_);
+    written_statement_position_ = current_statement_position_;
+  }
+
+  // Write the position if it is different from what was written last time and
+  // also different from the written statement position.
+  if (current_position_ != written_position_ &&
+      current_position_ != written_statement_position_) {
+    CheckBuffer();
+    RecordRelocInfo(RelocInfo::POSITION, current_position_);
+    written_position_ = current_position_;
+  }
+}
+
+
+void Assembler::GrowBuffer() {
+  if (!own_buffer_) FATAL("external code buffer is too small");
+
+  // compute new buffer size
+  CodeDesc desc;  // the new buffer
+  if (buffer_size_ < 4*KB) {
+    desc.buffer_size = 4*KB;
+  } else if (buffer_size_ < 1*MB) {
+    desc.buffer_size = 2*buffer_size_;
+  } else {
+    desc.buffer_size = buffer_size_ + 1*MB;
+  }
+  CHECK_GT(desc.buffer_size, 0);  // no overflow
+
+  // setup new buffer
+  desc.buffer = NewArray<byte>(desc.buffer_size);
+
+  desc.instr_size = pc_offset();
+  desc.reloc_size = (buffer_ + buffer_size_) - reloc_info_writer.pos();
+
+  // copy the data
+  int pc_delta = desc.buffer - buffer_;
+  int rc_delta = (desc.buffer + desc.buffer_size) - (buffer_ + buffer_size_);
+  memmove(desc.buffer, buffer_, desc.instr_size);
+  memmove(reloc_info_writer.pos() + rc_delta,
+          reloc_info_writer.pos(), desc.reloc_size);
+
+  // switch buffers
+  DeleteArray(buffer_);
+  buffer_ = desc.buffer;
+  buffer_size_ = desc.buffer_size;
+  pc_ += pc_delta;
+  reloc_info_writer.Reposition(reloc_info_writer.pos() + rc_delta,
+                               reloc_info_writer.last_pc() + pc_delta);
+
+  // none of our relocation types are pc relative pointing outside the code
+  // buffer nor pc absolute pointing inside the code buffer, so there is no need
+  // to relocate any emitted relocation entries
+
+  // relocate pending relocation entries
+  for (int i = 0; i < num_prinfo_; i++) {
+    RelocInfo& rinfo = prinfo_[i];
+    ASSERT(rinfo.rmode() != RelocInfo::COMMENT &&
+           rinfo.rmode() != RelocInfo::POSITION);
+    rinfo.set_pc(rinfo.pc() + pc_delta);
+  }
+}
+
+
+void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
+  RelocInfo rinfo(pc_, rmode, data);  // we do not try to reuse pool constants
+  if (rmode >= RelocInfo::COMMENT && rmode <= RelocInfo::STATEMENT_POSITION) {
+    // adjust code for new modes
+    ASSERT(RelocInfo::IsComment(rmode) || RelocInfo::IsPosition(rmode));
+    // these modes do not need an entry in the constant pool
+  } else {
+    ASSERT(num_prinfo_ < kMaxNumPRInfo);
+    prinfo_[num_prinfo_++] = rinfo;
+    // Make sure the constant pool is not emitted in place of the next
+    // instruction for which we just recorded relocation info
+    BlockConstPoolBefore(pc_offset() + kInstrSize);
+  }
+  if (rinfo.rmode() != RelocInfo::NONE) {
+    // Don't record external references unless the heap will be serialized.
+    if (rmode == RelocInfo::EXTERNAL_REFERENCE &&
+        !Serializer::enabled() &&
+        !FLAG_debug_code) {
+      return;
+    }
+    ASSERT(buffer_space() >= kMaxRelocSize);  // too late to grow buffer here
+    reloc_info_writer.Write(&rinfo);
+  }
+}
+
+
+void Assembler::CheckConstPool(bool force_emit, bool require_jump) {
+  // Calculate the offset of the next check. It will be overwritten
+  // when a const pool is generated or when const pools are being
+  // blocked for a specific range.
+  next_buffer_check_ = pc_offset() + kCheckConstInterval;
+
+  // There is nothing to do if there are no pending relocation info entries
+  if (num_prinfo_ == 0) return;
+
+  // We emit a constant pool at regular intervals of about kDistBetweenPools
+  // or when requested by parameter force_emit (e.g. after each function).
+  // We prefer not to emit a jump unless the max distance is reached or if we
+  // are running low on slots, which can happen if a lot of constants are being
+  // emitted (e.g. --debug-code and many static references).
+  int dist = pc_offset() - last_const_pool_end_;
+  if (!force_emit && dist < kMaxDistBetweenPools &&
+      (require_jump || dist < kDistBetweenPools) &&
+      // TODO(1236125): Cleanup the "magic" number below. We know that
+      // the code generation will test every kCheckConstIntervalInst.
+      // Thus we are safe as long as we generate less than 7 constant
+      // entries per instruction.
+      (num_prinfo_ < (kMaxNumPRInfo - (7 * kCheckConstIntervalInst)))) {
+    return;
+  }
+
+  // If we did not return by now, we need to emit the constant pool soon.
+
+  // However, some small sequences of instructions must not be broken up by the
+  // insertion of a constant pool; such sequences are protected by setting
+  // no_const_pool_before_, which is checked here. Also, recursive calls to
+  // CheckConstPool are blocked by no_const_pool_before_.
+  if (pc_offset() < no_const_pool_before_) {
+    // Emission is currently blocked; make sure we try again as soon as possible
+    next_buffer_check_ = no_const_pool_before_;
+
+    // Something is wrong if emission is forced and blocked at the same time
+    ASSERT(!force_emit);
+    return;
+  }
+
+  int jump_instr = require_jump ? kInstrSize : 0;
+
+  // Check that the code buffer is large enough before emitting the constant
+  // pool and relocation information (include the jump over the pool and the
+  // constant pool marker).
+  int max_needed_space =
+      jump_instr + kInstrSize + num_prinfo_*(kInstrSize + kMaxRelocSize);
+  while (buffer_space() <= (max_needed_space + kGap)) GrowBuffer();
+
+  // Block recursive calls to CheckConstPool
+  BlockConstPoolBefore(pc_offset() + jump_instr + kInstrSize +
+                       num_prinfo_*kInstrSize);
+  // Don't bother to check for the emit calls below.
+  next_buffer_check_ = no_const_pool_before_;
+
+  // Emit jump over constant pool if necessary
+  Label after_pool;
+  if (require_jump) b(&after_pool);
+
+  RecordComment("[ Constant Pool");
+
+  // Put down constant pool marker
+  // "Undefined instruction" as specified by A3.1 Instruction set encoding
+  emit(0x03000000 | num_prinfo_);
+
+  // Emit constant pool entries
+  for (int i = 0; i < num_prinfo_; i++) {
+    RelocInfo& rinfo = prinfo_[i];
+    ASSERT(rinfo.rmode() != RelocInfo::COMMENT &&
+           rinfo.rmode() != RelocInfo::POSITION &&
+           rinfo.rmode() != RelocInfo::STATEMENT_POSITION);
+    Instr instr = instr_at(rinfo.pc());
+    // Instruction to patch must be a ldr/str [pc, #offset]
+    // P and U set, B and W clear, Rn == pc, offset12 still 0
+    ASSERT((instr & (7*B25 | P | U | B | W | 15*B16 | Off12Mask)) ==
+           (2*B25 | P | U | pc.code()*B16));
+    int delta = pc_ - rinfo.pc() - 8;
+    ASSERT(delta >= -4);  // instr could be ldr pc, [pc, #-4] followed by targ32
+    if (delta < 0) {
+      instr &= ~U;
+      delta = -delta;
+    }
+    ASSERT(is_uint12(delta));
+    instr_at_put(rinfo.pc(), instr + delta);
+    emit(rinfo.data());
+  }
+  num_prinfo_ = 0;
+  last_const_pool_end_ = pc_offset();
+
+  RecordComment("]");
+
+  if (after_pool.is_linked()) {
+    bind(&after_pool);
+  }
+
+  // Since a constant pool was just emitted, move the check offset forward by
+  // the standard interval.
+  next_buffer_check_ = pc_offset() + kCheckConstInterval;
+}
+
+
+} }  // namespace v8::internal