src/ppc/assembler-ppc.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 2014 the V8 project authors. All rights reserved.

#include "src/v8.h"

#if V8_TARGET_ARCH_PPC

#include "src/base/bits.h"
#include "src/base/cpu.h"
#include "src/macro-assembler.h"
#include "src/ppc/assembler-ppc-inl.h"
#include "src/serialize.h"

namespace v8 {
namespace internal {

// Get the CPU features enabled by the build.
static unsigned CpuFeaturesImpliedByCompiler() {
  unsigned answer = 0;
  return answer;
}


void CpuFeatures::ProbeImpl(bool cross_compile) {
  supported_ |= CpuFeaturesImpliedByCompiler();
  cache_line_size_ = 128;

  // Only use statically determined features for cross compile (snapshot).
  if (cross_compile) return;

// Detect whether frim instruction is supported (POWER5+)
// For now we will just check for processors we know do not
// support it
#ifndef USE_SIMULATOR
  // Probe for additional features at runtime.
  base::CPU cpu;
#if V8_TARGET_ARCH_PPC64
  if (cpu.part() == base::CPU::PPC_POWER8) {
    supported_ |= (1u << FPR_GPR_MOV);
  }
#endif
  if (cpu.part() == base::CPU::PPC_POWER6 ||
      cpu.part() == base::CPU::PPC_POWER7 ||
      cpu.part() == base::CPU::PPC_POWER8) {
    supported_ |= (1u << LWSYNC);
  }
#if V8_OS_LINUX
  if (!(cpu.part() == base::CPU::PPC_G5 || cpu.part() == base::CPU::PPC_G4)) {
    // Assume support
    supported_ |= (1u << FPU);
  }
  if (cpu.cache_line_size() != 0) {
    cache_line_size_ = cpu.cache_line_size();
  }
#elif V8_OS_AIX
  // Assume support FP support and default cache line size
  supported_ |= (1u << FPU);
#endif
#else  // Simulator
  supported_ |= (1u << FPU);
  supported_ |= (1u << LWSYNC);
#if V8_TARGET_ARCH_PPC64
  supported_ |= (1u << FPR_GPR_MOV);
#endif
#endif
}


void CpuFeatures::PrintTarget() {
  const char* ppc_arch = NULL;

#if V8_TARGET_ARCH_PPC64
  ppc_arch = "ppc64";
#else
  ppc_arch = "ppc";
#endif

  printf("target %s\n", ppc_arch);
}


void CpuFeatures::PrintFeatures() {
  printf("FPU=%d\n", CpuFeatures::IsSupported(FPU));
}


Register ToRegister(int num) {
  DCHECK(num >= 0 && num < kNumRegisters);
  const Register kRegisters[] = {r0,  sp,  r2,  r3,  r4,  r5,  r6,  r7,
                                 r8,  r9,  r10, r11, ip,  r13, r14, r15,
                                 r16, r17, r18, r19, r20, r21, r22, r23,
                                 r24, r25, r26, r27, r28, r29, r30, fp};
  return kRegisters[num];
}


const char* DoubleRegister::AllocationIndexToString(int index) {
  DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
  const char* const names[] = {
      "d1",  "d2",  "d3",  "d4",  "d5",  "d6",  "d7",  "d8",  "d9",  "d10",
      "d11", "d12", "d15", "d16", "d17", "d18", "d19", "d20", "d21", "d22",
      "d23", "d24", "d25", "d26", "d27", "d28", "d29", "d30", "d31"};
  return names[index];
}


// -----------------------------------------------------------------------------
// Implementation of RelocInfo

const int RelocInfo::kApplyMask = 1 << RelocInfo::INTERNAL_REFERENCE;


bool RelocInfo::IsCodedSpecially() {
  // The deserializer needs to know whether a pointer is specially
  // coded.  Being specially coded on PPC means that it is a lis/ori
  // instruction sequence or is an out of line constant pool entry,
  // and these are always the case inside code objects.
  return true;
}


bool RelocInfo::IsInConstantPool() {
#if V8_OOL_CONSTANT_POOL
  return Assembler::IsConstantPoolLoadStart(pc_);
#else
  return false;
#endif
}


void RelocInfo::PatchCode(byte* instructions, int instruction_count) {
  // Patch the code at the current address with the supplied instructions.
  Instr* pc = reinterpret_cast<Instr*>(pc_);
  Instr* instr = reinterpret_cast<Instr*>(instructions);
  for (int i = 0; i < instruction_count; i++) {
    *(pc + i) = *(instr + i);
  }

  // Indicate that code has changed.
  CpuFeatures::FlushICache(pc_, instruction_count * Assembler::kInstrSize);
}


// 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-ppc-inl.h for inlined constructors

Operand::Operand(Handle<Object> handle) {
  AllowDeferredHandleDereference using_raw_address;
  rm_ = no_reg;
  // Verify all Objects referred by code are NOT in new space.
  Object* obj = *handle;
  if (obj->IsHeapObject()) {
    DCHECK(!HeapObject::cast(obj)->GetHeap()->InNewSpace(obj));
    imm_ = reinterpret_cast<intptr_t>(handle.location());
    rmode_ = RelocInfo::EMBEDDED_OBJECT;
  } else {
    // no relocation needed
    imm_ = reinterpret_cast<intptr_t>(obj);
    rmode_ = kRelocInfo_NONEPTR;
  }
}


MemOperand::MemOperand(Register rn, int32_t offset) {
  ra_ = rn;
  rb_ = no_reg;
  offset_ = offset;
}


MemOperand::MemOperand(Register ra, Register rb) {
  ra_ = ra;
  rb_ = rb;
  offset_ = 0;
}


// -----------------------------------------------------------------------------
// Specific instructions, constants, and masks.

// Spare buffer.
static const int kMinimalBufferSize = 4 * KB;


Assembler::Assembler(Isolate* isolate, void* buffer, int buffer_size)
    : AssemblerBase(isolate, buffer, buffer_size),
      recorded_ast_id_(TypeFeedbackId::None()),
#if V8_OOL_CONSTANT_POOL
      constant_pool_builder_(),
#endif
      positions_recorder_(this) {
  reloc_info_writer.Reposition(buffer_ + buffer_size_, pc_);

  no_trampoline_pool_before_ = 0;
  trampoline_pool_blocked_nesting_ = 0;
  // We leave space (kMaxBlockTrampolineSectionSize)
  // for BlockTrampolinePoolScope buffer.
  next_buffer_check_ =
      FLAG_force_long_branches ? kMaxInt : kMaxCondBranchReach -
                                               kMaxBlockTrampolineSectionSize;
  internal_trampoline_exception_ = false;
  last_bound_pos_ = 0;
  trampoline_emitted_ = FLAG_force_long_branches;
  unbound_labels_count_ = 0;
  ClearRecordedAstId();
}


void Assembler::GetCode(CodeDesc* desc) {
  // Set up code descriptor.
  desc->buffer = buffer_;
  desc->buffer_size = buffer_size_;
  desc->instr_size = pc_offset();
  desc->reloc_size = (buffer_ + buffer_size_) - reloc_info_writer.pos();
  desc->origin = this;
}


void Assembler::Align(int m) {
#if V8_TARGET_ARCH_PPC64
  DCHECK(m >= 4 && base::bits::IsPowerOfTwo64(m));
#else
  DCHECK(m >= 4 && base::bits::IsPowerOfTwo32(m));
#endif
  while ((pc_offset() & (m - 1)) != 0) {
    nop();
  }
}


void Assembler::CodeTargetAlign() { Align(8); }


Condition Assembler::GetCondition(Instr instr) {
  switch (instr & kCondMask) {
    case BT:
      return eq;
    case BF:
      return ne;
    default:
      UNIMPLEMENTED();
  }
  return al;
}


bool Assembler::IsLis(Instr instr) {
  return ((instr & kOpcodeMask) == ADDIS) && GetRA(instr).is(r0);
}


bool Assembler::IsLi(Instr instr) {
  return ((instr & kOpcodeMask) == ADDI) && GetRA(instr).is(r0);
}


bool Assembler::IsAddic(Instr instr) { return (instr & kOpcodeMask) == ADDIC; }


bool Assembler::IsOri(Instr instr) { return (instr & kOpcodeMask) == ORI; }


bool Assembler::IsBranch(Instr instr) { return ((instr & kOpcodeMask) == BCX); }


Register Assembler::GetRA(Instr instr) {
  Register reg;
  reg.code_ = Instruction::RAValue(instr);
  return reg;
}


Register Assembler::GetRB(Instr instr) {
  Register reg;
  reg.code_ = Instruction::RBValue(instr);
  return reg;
}


#if V8_TARGET_ARCH_PPC64
// This code assumes a FIXED_SEQUENCE for 64bit loads (lis/ori)
bool Assembler::Is64BitLoadIntoR12(Instr instr1, Instr instr2, Instr instr3,
                                   Instr instr4, Instr instr5) {
  // Check the instructions are indeed a five part load (into r12)
  // 3d800000       lis     r12, 0
  // 618c0000       ori     r12, r12, 0
  // 798c07c6       rldicr  r12, r12, 32, 31
  // 658c00c3       oris    r12, r12, 195
  // 618ccd40       ori     r12, r12, 52544
  return (((instr1 >> 16) == 0x3d80) && ((instr2 >> 16) == 0x618c) &&
          (instr3 == 0x798c07c6) && ((instr4 >> 16) == 0x658c) &&
          ((instr5 >> 16) == 0x618c));
}
#else
// This code assumes a FIXED_SEQUENCE for 32bit loads (lis/ori)
bool Assembler::Is32BitLoadIntoR12(Instr instr1, Instr instr2) {
  // Check the instruction is indeed a two part load (into r12)
  // 3d802553       lis     r12, 9555
  // 618c5000       ori   r12, r12, 20480
  return (((instr1 >> 16) == 0x3d80) && ((instr2 >> 16) == 0x618c));
}
#endif


bool Assembler::IsCmpRegister(Instr instr) {
  return (((instr & kOpcodeMask) == EXT2) &&
          ((instr & kExt2OpcodeMask) == CMP));
}


bool Assembler::IsRlwinm(Instr instr) {
  return ((instr & kOpcodeMask) == RLWINMX);
}


#if V8_TARGET_ARCH_PPC64
bool Assembler::IsRldicl(Instr instr) {
  return (((instr & kOpcodeMask) == EXT5) &&
          ((instr & kExt5OpcodeMask) == RLDICL));
}
#endif


bool Assembler::IsCmpImmediate(Instr instr) {
  return ((instr & kOpcodeMask) == CMPI);
}


bool Assembler::IsCrSet(Instr instr) {
  return (((instr & kOpcodeMask) == EXT1) &&
          ((instr & kExt1OpcodeMask) == CREQV));
}


Register Assembler::GetCmpImmediateRegister(Instr instr) {
  DCHECK(IsCmpImmediate(instr));
  return GetRA(instr);
}


int Assembler::GetCmpImmediateRawImmediate(Instr instr) {
  DCHECK(IsCmpImmediate(instr));
  return instr & kOff16Mask;
}


// 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);
  // check which type of branch this is 16 or 26 bit offset
  int opcode = instr & kOpcodeMask;
  if (BX == opcode) {
    int imm26 = ((instr & kImm26Mask) << 6) >> 6;
    imm26 &= ~(kAAMask | kLKMask);  // discard AA|LK bits if present
    if (imm26 == 0) return kEndOfChain;
    return pos + imm26;
  } else if (BCX == opcode) {
    int imm16 = SIGN_EXT_IMM16((instr & kImm16Mask));
    imm16 &= ~(kAAMask | kLKMask);  // discard AA|LK bits if present
    if (imm16 == 0) return kEndOfChain;
    return pos + imm16;
  } else if ((instr & ~kImm26Mask) == 0) {
    // Emitted link to a label, not part of a branch (regexp PushBacktrack).
    if (instr == 0) {
      return kEndOfChain;
    } else {
      int32_t imm26 = SIGN_EXT_IMM26(instr);
      return (imm26 + pos);
    }
  }

  PPCPORT_UNIMPLEMENTED();
  DCHECK(false);
  return -1;
}


void Assembler::target_at_put(int pos, int target_pos) {
  Instr instr = instr_at(pos);
  int opcode = instr & kOpcodeMask;

  // check which type of branch this is 16 or 26 bit offset
  if (BX == opcode) {
    int imm26 = target_pos - pos;
    DCHECK((imm26 & (kAAMask | kLKMask)) == 0);
    instr &= ((~kImm26Mask) | kAAMask | kLKMask);
    DCHECK(is_int26(imm26));
    instr_at_put(pos, instr | (imm26 & kImm26Mask));
    return;
  } else if (BCX == opcode) {
    int imm16 = target_pos - pos;
    DCHECK((imm16 & (kAAMask | kLKMask)) == 0);
    instr &= ((~kImm16Mask) | kAAMask | kLKMask);
    DCHECK(is_int16(imm16));
    instr_at_put(pos, instr | (imm16 & kImm16Mask));
    return;
  } else if ((instr & ~kImm26Mask) == 0) {
    DCHECK(target_pos == kEndOfChain || target_pos >= 0);
    // Emitted link to a label, not part of a branch (regexp PushBacktrack).
    // Load the position of the label relative to the generated code object
    // pointer in a register.

    Register dst = r3;  // we assume r3 for now
    DCHECK(IsNop(instr_at(pos + kInstrSize)));
    uint32_t target = target_pos + (Code::kHeaderSize - kHeapObjectTag);
    CodePatcher patcher(reinterpret_cast<byte*>(buffer_ + pos), 2,
                        CodePatcher::DONT_FLUSH);
    int target_hi = static_cast<int>(target) >> 16;
    int target_lo = static_cast<int>(target) & 0XFFFF;

    patcher.masm()->lis(dst, Operand(SIGN_EXT_IMM16(target_hi)));
    patcher.masm()->ori(dst, dst, Operand(target_lo));
    return;
  }

  DCHECK(false);
}


int Assembler::max_reach_from(int pos) {
  Instr instr = instr_at(pos);
  int opcode = instr & kOpcodeMask;

  // check which type of branch this is 16 or 26 bit offset
  if (BX == opcode) {
    return 26;
  } else if (BCX == opcode) {
    return 16;
  } else if ((instr & ~kImm26Mask) == 0) {
    // Emitted label constant, not part of a branch (regexp PushBacktrack).
    return 26;
  }

  DCHECK(false);
  return 0;
}


void Assembler::bind_to(Label* L, int pos) {
  DCHECK(0 <= pos && pos <= pc_offset());  // must have a valid binding position
  int32_t trampoline_pos = kInvalidSlotPos;
  if (L->is_linked() && !trampoline_emitted_) {
    unbound_labels_count_--;
    next_buffer_check_ += kTrampolineSlotsSize;
  }

  while (L->is_linked()) {
    int fixup_pos = L->pos();
    int32_t offset = pos - fixup_pos;
    int maxReach = max_reach_from(fixup_pos);
    next(L);  // call next before overwriting link with target at fixup_pos
    if (is_intn(offset, maxReach) == false) {
      if (trampoline_pos == kInvalidSlotPos) {
        trampoline_pos = get_trampoline_entry();
        CHECK(trampoline_pos != kInvalidSlotPos);
        target_at_put(trampoline_pos, pos);
      }
      target_at_put(fixup_pos, trampoline_pos);
    } else {
      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::bind(Label* L) {
  DCHECK(!L->is_bound());  // label can only be bound once
  bind_to(L, pc_offset());
}


void Assembler::next(Label* L) {
  DCHECK(L->is_linked());
  int link = target_at(L->pos());
  if (link == kEndOfChain) {
    L->Unuse();
  } else {
    DCHECK(link >= 0);
    L->link_to(link);
  }
}


bool Assembler::is_near(Label* L, Condition cond) {
  DCHECK(L->is_bound());
  if (L->is_bound() == false) return false;

  int maxReach = ((cond == al) ? 26 : 16);
  int offset = L->pos() - pc_offset();

  return is_intn(offset, maxReach);
}


void Assembler::a_form(Instr instr, DoubleRegister frt, DoubleRegister fra,
                       DoubleRegister frb, RCBit r) {
  emit(instr | frt.code() * B21 | fra.code() * B16 | frb.code() * B11 | r);
}


void Assembler::d_form(Instr instr, Register rt, Register ra,
                       const intptr_t val, bool signed_disp) {
  if (signed_disp) {
    if (!is_int16(val)) {
      PrintF("val = %" V8PRIdPTR ", 0x%" V8PRIxPTR "\n", val, val);
    }
    DCHECK(is_int16(val));
  } else {
    if (!is_uint16(val)) {
      PrintF("val = %" V8PRIdPTR ", 0x%" V8PRIxPTR
             ", is_unsigned_imm16(val)=%d, kImm16Mask=0x%x\n",
             val, val, is_uint16(val), kImm16Mask);
    }
    DCHECK(is_uint16(val));
  }
  emit(instr | rt.code() * B21 | ra.code() * B16 | (kImm16Mask & val));
}


void Assembler::x_form(Instr instr, Register ra, Register rs, Register rb,
                       RCBit r) {
  emit(instr | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 | r);
}


void Assembler::xo_form(Instr instr, Register rt, Register ra, Register rb,
                        OEBit o, RCBit r) {
  emit(instr | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 | o | r);
}


void Assembler::md_form(Instr instr, Register ra, Register rs, int shift,
                        int maskbit, RCBit r) {
  int sh0_4 = shift & 0x1f;
  int sh5 = (shift >> 5) & 0x1;
  int m0_4 = maskbit & 0x1f;
  int m5 = (maskbit >> 5) & 0x1;

  emit(instr | rs.code() * B21 | ra.code() * B16 | sh0_4 * B11 | m0_4 * B6 |
       m5 * B5 | sh5 * B1 | r);
}


void Assembler::mds_form(Instr instr, Register ra, Register rs, Register rb,
                         int maskbit, RCBit r) {
  int m0_4 = maskbit & 0x1f;
  int m5 = (maskbit >> 5) & 0x1;

  emit(instr | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 | m0_4 * B6 |
       m5 * B5 | r);
}


// Returns the next free trampoline entry.
int32_t Assembler::get_trampoline_entry() {
  int32_t trampoline_entry = kInvalidSlotPos;

  if (!internal_trampoline_exception_) {
    trampoline_entry = trampoline_.take_slot();

    if (kInvalidSlotPos == trampoline_entry) {
      internal_trampoline_exception_ = true;
    }
  }
  return trampoline_entry;
}


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 {
      // was: target_pos = kEndOfChain;
      // However, using branch to self to mark the first reference
      // should avoid most instances of branch offset overflow.  See
      // target_at() for where this is converted back to kEndOfChain.
      target_pos = pc_offset();
      if (!trampoline_emitted_) {
        unbound_labels_count_++;
        next_buffer_check_ -= kTrampolineSlotsSize;
      }
    }
    L->link_to(pc_offset());
  }

  return target_pos - pc_offset();
}


// Branch instructions.


void Assembler::bclr(BOfield bo, LKBit lk) {
  positions_recorder()->WriteRecordedPositions();
  emit(EXT1 | bo | BCLRX | lk);
}


void Assembler::bcctr(BOfield bo, LKBit lk) {
  positions_recorder()->WriteRecordedPositions();
  emit(EXT1 | bo | BCCTRX | lk);
}


// Pseudo op - branch to link register
void Assembler::blr() { bclr(BA, LeaveLK); }


// Pseudo op - branch to count register -- used for "jump"
void Assembler::bctr() { bcctr(BA, LeaveLK); }


void Assembler::bctrl() { bcctr(BA, SetLK); }


void Assembler::bc(int branch_offset, BOfield bo, int condition_bit, LKBit lk) {
  if (lk == SetLK) {
    positions_recorder()->WriteRecordedPositions();
  }
  DCHECK(is_int16(branch_offset));
  emit(BCX | bo | condition_bit * B16 | (kImm16Mask & branch_offset) | lk);
}


void Assembler::b(int branch_offset, LKBit lk) {
  if (lk == SetLK) {
    positions_recorder()->WriteRecordedPositions();
  }
  DCHECK((branch_offset & 3) == 0);
  int imm26 = branch_offset;
  DCHECK(is_int26(imm26));
  // todo add AA and LK bits
  emit(BX | (imm26 & kImm26Mask) | lk);
}


void Assembler::xori(Register dst, Register src, const Operand& imm) {
  d_form(XORI, src, dst, imm.imm_, false);
}


void Assembler::xoris(Register ra, Register rs, const Operand& imm) {
  d_form(XORIS, rs, ra, imm.imm_, false);
}


void Assembler::xor_(Register dst, Register src1, Register src2, RCBit rc) {
  x_form(EXT2 | XORX, dst, src1, src2, rc);
}


void Assembler::cntlzw_(Register ra, Register rs, RCBit rc) {
  x_form(EXT2 | CNTLZWX, ra, rs, r0, rc);
}


void Assembler::and_(Register ra, Register rs, Register rb, RCBit rc) {
  x_form(EXT2 | ANDX, ra, rs, rb, rc);
}


void Assembler::rlwinm(Register ra, Register rs, int sh, int mb, int me,
                       RCBit rc) {
  sh &= 0x1f;
  mb &= 0x1f;
  me &= 0x1f;
  emit(RLWINMX | rs.code() * B21 | ra.code() * B16 | sh * B11 | mb * B6 |
       me << 1 | rc);
}


void Assembler::rlwnm(Register ra, Register rs, Register rb, int mb, int me,
                      RCBit rc) {
  mb &= 0x1f;
  me &= 0x1f;
  emit(RLWNMX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 | mb * B6 |
       me << 1 | rc);
}


void Assembler::rlwimi(Register ra, Register rs, int sh, int mb, int me,
                       RCBit rc) {
  sh &= 0x1f;
  mb &= 0x1f;
  me &= 0x1f;
  emit(RLWIMIX | rs.code() * B21 | ra.code() * B16 | sh * B11 | mb * B6 |
       me << 1 | rc);
}


void Assembler::slwi(Register dst, Register src, const Operand& val, RCBit rc) {
  DCHECK((32 > val.imm_) && (val.imm_ >= 0));
  rlwinm(dst, src, val.imm_, 0, 31 - val.imm_, rc);
}


void Assembler::srwi(Register dst, Register src, const Operand& val, RCBit rc) {
  DCHECK((32 > val.imm_) && (val.imm_ >= 0));
  rlwinm(dst, src, 32 - val.imm_, val.imm_, 31, rc);
}


void Assembler::clrrwi(Register dst, Register src, const Operand& val,
                       RCBit rc) {
  DCHECK((32 > val.imm_) && (val.imm_ >= 0));
  rlwinm(dst, src, 0, 0, 31 - val.imm_, rc);
}


void Assembler::clrlwi(Register dst, Register src, const Operand& val,
                       RCBit rc) {
  DCHECK((32 > val.imm_) && (val.imm_ >= 0));
  rlwinm(dst, src, 0, val.imm_, 31, rc);
}


void Assembler::srawi(Register ra, Register rs, int sh, RCBit r) {
  emit(EXT2 | SRAWIX | rs.code() * B21 | ra.code() * B16 | sh * B11 | r);
}


void Assembler::srw(Register dst, Register src1, Register src2, RCBit r) {
  x_form(EXT2 | SRWX, dst, src1, src2, r);
}


void Assembler::slw(Register dst, Register src1, Register src2, RCBit r) {
  x_form(EXT2 | SLWX, dst, src1, src2, r);
}


void Assembler::sraw(Register ra, Register rs, Register rb, RCBit r) {
  x_form(EXT2 | SRAW, ra, rs, rb, r);
}


void Assembler::rotlw(Register ra, Register rs, Register rb, RCBit r) {
  rlwnm(ra, rs, rb, 0, 31, r);
}


void Assembler::rotlwi(Register ra, Register rs, int sh, RCBit r) {
  rlwinm(ra, rs, sh, 0, 31, r);
}


void Assembler::rotrwi(Register ra, Register rs, int sh, RCBit r) {
  rlwinm(ra, rs, 32 - sh, 0, 31, r);
}


void Assembler::subi(Register dst, Register src, const Operand& imm) {
  addi(dst, src, Operand(-(imm.imm_)));
}

void Assembler::addc(Register dst, Register src1, Register src2, OEBit o,
                     RCBit r) {
  xo_form(EXT2 | ADDCX, dst, src1, src2, o, r);
}


void Assembler::addze(Register dst, Register src1, OEBit o, RCBit r) {
  // a special xo_form
  emit(EXT2 | ADDZEX | dst.code() * B21 | src1.code() * B16 | o | r);
}


void Assembler::sub(Register dst, Register src1, Register src2, OEBit o,
                    RCBit r) {
  xo_form(EXT2 | SUBFX, dst, src2, src1, o, r);
}


void Assembler::subfc(Register dst, Register src1, Register src2, OEBit o,
                      RCBit r) {
  xo_form(EXT2 | SUBFCX, dst, src2, src1, o, r);
}


void Assembler::subfic(Register dst, Register src, const Operand& imm) {
  d_form(SUBFIC, dst, src, imm.imm_, true);
}


void Assembler::add(Register dst, Register src1, Register src2, OEBit o,
                    RCBit r) {
  xo_form(EXT2 | ADDX, dst, src1, src2, o, r);
}


// Multiply low word
void Assembler::mullw(Register dst, Register src1, Register src2, OEBit o,
                      RCBit r) {
  xo_form(EXT2 | MULLW, dst, src1, src2, o, r);
}


// Multiply hi word
void Assembler::mulhw(Register dst, Register src1, Register src2, OEBit o,
                      RCBit r) {
  xo_form(EXT2 | MULHWX, dst, src1, src2, o, r);
}


// Divide word
void Assembler::divw(Register dst, Register src1, Register src2, OEBit o,
                     RCBit r) {
  xo_form(EXT2 | DIVW, dst, src1, src2, o, r);
}


void Assembler::addi(Register dst, Register src, const Operand& imm) {
  DCHECK(!src.is(r0));  // use li instead to show intent
  d_form(ADDI, dst, src, imm.imm_, true);
}


void Assembler::addis(Register dst, Register src, const Operand& imm) {
  DCHECK(!src.is(r0));  // use lis instead to show intent
  d_form(ADDIS, dst, src, imm.imm_, true);
}


void Assembler::addic(Register dst, Register src, const Operand& imm) {
  d_form(ADDIC, dst, src, imm.imm_, true);
}


void Assembler::andi(Register ra, Register rs, const Operand& imm) {
  d_form(ANDIx, rs, ra, imm.imm_, false);
}


void Assembler::andis(Register ra, Register rs, const Operand& imm) {
  d_form(ANDISx, rs, ra, imm.imm_, false);
}


void Assembler::nor(Register dst, Register src1, Register src2, RCBit r) {
  x_form(EXT2 | NORX, dst, src1, src2, r);
}


void Assembler::notx(Register dst, Register src, RCBit r) {
  x_form(EXT2 | NORX, dst, src, src, r);
}


void Assembler::ori(Register ra, Register rs, const Operand& imm) {
  d_form(ORI, rs, ra, imm.imm_, false);
}


void Assembler::oris(Register dst, Register src, const Operand& imm) {
  d_form(ORIS, src, dst, imm.imm_, false);
}


void Assembler::orx(Register dst, Register src1, Register src2, RCBit rc) {
  x_form(EXT2 | ORX, dst, src1, src2, rc);
}


void Assembler::cmpi(Register src1, const Operand& src2, CRegister cr) {
  intptr_t imm16 = src2.imm_;
#if V8_TARGET_ARCH_PPC64
  int L = 1;
#else
  int L = 0;
#endif
  DCHECK(is_int16(imm16));
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  imm16 &= kImm16Mask;
  emit(CMPI | cr.code() * B23 | L * B21 | src1.code() * B16 | imm16);
}


void Assembler::cmpli(Register src1, const Operand& src2, CRegister cr) {
  uintptr_t uimm16 = src2.imm_;
#if V8_TARGET_ARCH_PPC64
  int L = 1;
#else
  int L = 0;
#endif
  DCHECK(is_uint16(uimm16));
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  uimm16 &= kImm16Mask;
  emit(CMPLI | cr.code() * B23 | L * B21 | src1.code() * B16 | uimm16);
}


void Assembler::cmp(Register src1, Register src2, CRegister cr) {
#if V8_TARGET_ARCH_PPC64
  int L = 1;
#else
  int L = 0;
#endif
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  emit(EXT2 | CMP | cr.code() * B23 | L * B21 | src1.code() * B16 |
       src2.code() * B11);
}


void Assembler::cmpl(Register src1, Register src2, CRegister cr) {
#if V8_TARGET_ARCH_PPC64
  int L = 1;
#else
  int L = 0;
#endif
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  emit(EXT2 | CMPL | cr.code() * B23 | L * B21 | src1.code() * B16 |
       src2.code() * B11);
}


void Assembler::cmpwi(Register src1, const Operand& src2, CRegister cr) {
  intptr_t imm16 = src2.imm_;
  int L = 0;
  DCHECK(is_int16(imm16));
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  imm16 &= kImm16Mask;
  emit(CMPI | cr.code() * B23 | L * B21 | src1.code() * B16 | imm16);
}


void Assembler::cmplwi(Register src1, const Operand& src2, CRegister cr) {
  uintptr_t uimm16 = src2.imm_;
  int L = 0;
  DCHECK(is_uint16(uimm16));
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  uimm16 &= kImm16Mask;
  emit(CMPLI | cr.code() * B23 | L * B21 | src1.code() * B16 | uimm16);
}


void Assembler::cmpw(Register src1, Register src2, CRegister cr) {
  int L = 0;
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  emit(EXT2 | CMP | cr.code() * B23 | L * B21 | src1.code() * B16 |
       src2.code() * B11);
}


void Assembler::cmplw(Register src1, Register src2, CRegister cr) {
  int L = 0;
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  emit(EXT2 | CMPL | cr.code() * B23 | L * B21 | src1.code() * B16 |
       src2.code() * B11);
}


// Pseudo op - load immediate
void Assembler::li(Register dst, const Operand& imm) {
  d_form(ADDI, dst, r0, imm.imm_, true);
}


void Assembler::lis(Register dst, const Operand& imm) {
  d_form(ADDIS, dst, r0, imm.imm_, true);
}


// Pseudo op - move register
void Assembler::mr(Register dst, Register src) {
  // actually or(dst, src, src)
  orx(dst, src, src);
}


void Assembler::lbz(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(LBZ, dst, src.ra(), src.offset(), true);
}


void Assembler::lbzx(Register rt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LBZX | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lbzux(Register rt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LBZUX | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lhz(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(LHZ, dst, src.ra(), src.offset(), true);
}


void Assembler::lhzx(Register rt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LHZX | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lhzux(Register rt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LHZUX | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lwz(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(LWZ, dst, src.ra(), src.offset(), true);
}


void Assembler::lwzu(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(LWZU, dst, src.ra(), src.offset(), true);
}


void Assembler::lwzx(Register rt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LWZX | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lwzux(Register rt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LWZUX | rt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lwa(Register dst, const MemOperand& src) {
#if V8_TARGET_ARCH_PPC64
  int offset = src.offset();
  DCHECK(!src.ra_.is(r0));
  DCHECK(!(offset & 3) && is_int16(offset));
  offset = kImm16Mask & offset;
  emit(LD | dst.code() * B21 | src.ra().code() * B16 | offset | 2);
#else
  lwz(dst, src);
#endif
}


void Assembler::stb(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(STB, dst, src.ra(), src.offset(), true);
}


void Assembler::stbx(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STBX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stbux(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STBUX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::sth(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(STH, dst, src.ra(), src.offset(), true);
}


void Assembler::sthx(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STHX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::sthux(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STHUX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stw(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(STW, dst, src.ra(), src.offset(), true);
}


void Assembler::stwu(Register dst, const MemOperand& src) {
  DCHECK(!src.ra_.is(r0));
  d_form(STWU, dst, src.ra(), src.offset(), true);
}


void Assembler::stwx(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STWX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stwux(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STWUX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::extsb(Register rs, Register ra, RCBit rc) {
  emit(EXT2 | EXTSB | ra.code() * B21 | rs.code() * B16 | rc);
}


void Assembler::extsh(Register rs, Register ra, RCBit rc) {
  emit(EXT2 | EXTSH | ra.code() * B21 | rs.code() * B16 | rc);
}


void Assembler::neg(Register rt, Register ra, OEBit o, RCBit r) {
  emit(EXT2 | NEGX | rt.code() * B21 | ra.code() * B16 | o | r);
}


void Assembler::andc(Register dst, Register src1, Register src2, RCBit rc) {
  x_form(EXT2 | ANDCX, dst, src1, src2, rc);
}


#if V8_TARGET_ARCH_PPC64
// 64bit specific instructions
void Assembler::ld(Register rd, const MemOperand& src) {
  int offset = src.offset();
  DCHECK(!src.ra_.is(r0));
  DCHECK(!(offset & 3) && is_int16(offset));
  offset = kImm16Mask & offset;
  emit(LD | rd.code() * B21 | src.ra().code() * B16 | offset);
}


void Assembler::ldx(Register rd, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LDX | rd.code() * B21 | ra.code() * B16 | rb.code() * B11);
}


void Assembler::ldu(Register rd, const MemOperand& src) {
  int offset = src.offset();
  DCHECK(!src.ra_.is(r0));
  DCHECK(!(offset & 3) && is_int16(offset));
  offset = kImm16Mask & offset;
  emit(LD | rd.code() * B21 | src.ra().code() * B16 | offset | 1);
}


void Assembler::ldux(Register rd, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LDUX | rd.code() * B21 | ra.code() * B16 | rb.code() * B11);
}


void Assembler::std(Register rs, const MemOperand& src) {
  int offset = src.offset();
  DCHECK(!src.ra_.is(r0));
  DCHECK(!(offset & 3) && is_int16(offset));
  offset = kImm16Mask & offset;
  emit(STD | rs.code() * B21 | src.ra().code() * B16 | offset);
}


void Assembler::stdx(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STDX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11);
}


void Assembler::stdu(Register rs, const MemOperand& src) {
  int offset = src.offset();
  DCHECK(!src.ra_.is(r0));
  DCHECK(!(offset & 3) && is_int16(offset));
  offset = kImm16Mask & offset;
  emit(STD | rs.code() * B21 | src.ra().code() * B16 | offset | 1);
}


void Assembler::stdux(Register rs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STDUX | rs.code() * B21 | ra.code() * B16 | rb.code() * B11);
}


void Assembler::rldic(Register ra, Register rs, int sh, int mb, RCBit r) {
  md_form(EXT5 | RLDIC, ra, rs, sh, mb, r);
}


void Assembler::rldicl(Register ra, Register rs, int sh, int mb, RCBit r) {
  md_form(EXT5 | RLDICL, ra, rs, sh, mb, r);
}


void Assembler::rldcl(Register ra, Register rs, Register rb, int mb, RCBit r) {
  mds_form(EXT5 | RLDCL, ra, rs, rb, mb, r);
}


void Assembler::rldicr(Register ra, Register rs, int sh, int me, RCBit r) {
  md_form(EXT5 | RLDICR, ra, rs, sh, me, r);
}


void Assembler::sldi(Register dst, Register src, const Operand& val, RCBit rc) {
  DCHECK((64 > val.imm_) && (val.imm_ >= 0));
  rldicr(dst, src, val.imm_, 63 - val.imm_, rc);
}


void Assembler::srdi(Register dst, Register src, const Operand& val, RCBit rc) {
  DCHECK((64 > val.imm_) && (val.imm_ >= 0));
  rldicl(dst, src, 64 - val.imm_, val.imm_, rc);
}


void Assembler::clrrdi(Register dst, Register src, const Operand& val,
                       RCBit rc) {
  DCHECK((64 > val.imm_) && (val.imm_ >= 0));
  rldicr(dst, src, 0, 63 - val.imm_, rc);
}


void Assembler::clrldi(Register dst, Register src, const Operand& val,
                       RCBit rc) {
  DCHECK((64 > val.imm_) && (val.imm_ >= 0));
  rldicl(dst, src, 0, val.imm_, rc);
}


void Assembler::rldimi(Register ra, Register rs, int sh, int mb, RCBit r) {
  md_form(EXT5 | RLDIMI, ra, rs, sh, mb, r);
}


void Assembler::sradi(Register ra, Register rs, int sh, RCBit r) {
  int sh0_4 = sh & 0x1f;
  int sh5 = (sh >> 5) & 0x1;

  emit(EXT2 | SRADIX | rs.code() * B21 | ra.code() * B16 | sh0_4 * B11 |
       sh5 * B1 | r);
}


void Assembler::srd(Register dst, Register src1, Register src2, RCBit r) {
  x_form(EXT2 | SRDX, dst, src1, src2, r);
}


void Assembler::sld(Register dst, Register src1, Register src2, RCBit r) {
  x_form(EXT2 | SLDX, dst, src1, src2, r);
}


void Assembler::srad(Register ra, Register rs, Register rb, RCBit r) {
  x_form(EXT2 | SRAD, ra, rs, rb, r);
}


void Assembler::rotld(Register ra, Register rs, Register rb, RCBit r) {
  rldcl(ra, rs, rb, 0, r);
}


void Assembler::rotldi(Register ra, Register rs, int sh, RCBit r) {
  rldicl(ra, rs, sh, 0, r);
}


void Assembler::rotrdi(Register ra, Register rs, int sh, RCBit r) {
  rldicl(ra, rs, 64 - sh, 0, r);
}


void Assembler::cntlzd_(Register ra, Register rs, RCBit rc) {
  x_form(EXT2 | CNTLZDX, ra, rs, r0, rc);
}


void Assembler::extsw(Register rs, Register ra, RCBit rc) {
  emit(EXT2 | EXTSW | ra.code() * B21 | rs.code() * B16 | rc);
}


void Assembler::mulld(Register dst, Register src1, Register src2, OEBit o,
                      RCBit r) {
  xo_form(EXT2 | MULLD, dst, src1, src2, o, r);
}


void Assembler::divd(Register dst, Register src1, Register src2, OEBit o,
                     RCBit r) {
  xo_form(EXT2 | DIVD, dst, src1, src2, o, r);
}
#endif


void Assembler::fake_asm(enum FAKE_OPCODE_T fopcode) {
  DCHECK(fopcode < fLastFaker);
  emit(FAKE_OPCODE | FAKER_SUBOPCODE | fopcode);
}


void Assembler::marker_asm(int mcode) {
  if (::v8::internal::FLAG_trace_sim_stubs) {
    DCHECK(mcode < F_NEXT_AVAILABLE_STUB_MARKER);
    emit(FAKE_OPCODE | MARKER_SUBOPCODE | mcode);
  }
}


// Function descriptor for AIX.
// Code address skips the function descriptor "header".
// TOC and static chain are ignored and set to 0.
void Assembler::function_descriptor() {
  DCHECK(pc_offset() == 0);
  RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE);
  emit_ptr(reinterpret_cast<uintptr_t>(pc_) + 3 * kPointerSize);
  emit_ptr(0);
  emit_ptr(0);
}


#if ABI_USES_FUNCTION_DESCRIPTORS || V8_OOL_CONSTANT_POOL
void Assembler::RelocateInternalReference(Address pc, intptr_t delta,
                                          Address code_start,
                                          ICacheFlushMode icache_flush_mode) {
  DCHECK(delta || code_start);
#if ABI_USES_FUNCTION_DESCRIPTORS
  uintptr_t* fd = reinterpret_cast<uintptr_t*>(pc);
  if (fd[1] == 0 && fd[2] == 0) {
    // Function descriptor
    if (delta) {
      fd[0] += delta;
    } else {
      fd[0] = reinterpret_cast<uintptr_t>(code_start) + 3 * kPointerSize;
    }
    return;
  }
#endif
#if V8_OOL_CONSTANT_POOL
  // mov for LoadConstantPoolPointerRegister
  ConstantPoolArray* constant_pool = NULL;
  if (delta) {
    code_start = target_address_at(pc, constant_pool) + delta;
  }
  set_target_address_at(pc, constant_pool, code_start, icache_flush_mode);
#endif
}


int Assembler::DecodeInternalReference(Vector<char> buffer, Address pc) {
#if ABI_USES_FUNCTION_DESCRIPTORS
  uintptr_t* fd = reinterpret_cast<uintptr_t*>(pc);
  if (fd[1] == 0 && fd[2] == 0) {
    // Function descriptor
    SNPrintF(buffer, "[%08" V8PRIxPTR ", %08" V8PRIxPTR ", %08" V8PRIxPTR
                     "]"
                     "   function descriptor",
             fd[0], fd[1], fd[2]);
    return kPointerSize * 3;
  }
#endif
  return 0;
}
#endif


int Assembler::instructions_required_for_mov(const Operand& x) const {
#if V8_OOL_CONSTANT_POOL || DEBUG
  bool canOptimize =
      !(x.must_output_reloc_info(this) || is_trampoline_pool_blocked());
#endif
#if V8_OOL_CONSTANT_POOL
  if (use_constant_pool_for_mov(x, canOptimize)) {
    // Current usage guarantees that all constant pool references can
    // use the same sequence.
    return kMovInstructionsConstantPool;
  }
#endif
  DCHECK(!canOptimize);
  return kMovInstructionsNoConstantPool;
}


#if V8_OOL_CONSTANT_POOL
bool Assembler::use_constant_pool_for_mov(const Operand& x,
                                          bool canOptimize) const {
  if (!is_ool_constant_pool_available() || is_constant_pool_full()) {
    // If there is no constant pool available, we must use a mov
    // immediate sequence.
    return false;
  }

  intptr_t value = x.immediate();
  if (canOptimize && is_int16(value)) {
    // Prefer a single-instruction load-immediate.
    return false;
  }

  return true;
}


void Assembler::EnsureSpaceFor(int space_needed) {
  if (buffer_space() <= (kGap + space_needed)) {
    GrowBuffer();
  }
}
#endif


bool Operand::must_output_reloc_info(const Assembler* assembler) const {
  if (rmode_ == RelocInfo::EXTERNAL_REFERENCE) {
    if (assembler != NULL && assembler->predictable_code_size()) return true;
    return assembler->serializer_enabled();
  } else if (RelocInfo::IsNone(rmode_)) {
    return false;
  }
  return true;
}


// Primarily used for loading constants
// This should really move to be in macro-assembler as it
// is really a pseudo instruction
// Some usages of this intend for a FIXED_SEQUENCE to be used
// Todo - break this dependency so we can optimize mov() in general
// and only use the generic version when we require a fixed sequence
void Assembler::mov(Register dst, const Operand& src) {
  intptr_t value = src.immediate();
  bool canOptimize;
  RelocInfo rinfo(pc_, src.rmode_, value, NULL);

  if (src.must_output_reloc_info(this)) {
    RecordRelocInfo(rinfo);
  }

  canOptimize =
      !(src.must_output_reloc_info(this) || is_trampoline_pool_blocked());

#if V8_OOL_CONSTANT_POOL
  if (use_constant_pool_for_mov(src, canOptimize)) {
    DCHECK(is_ool_constant_pool_available());
    ConstantPoolAddEntry(rinfo);
#if V8_TARGET_ARCH_PPC64
    BlockTrampolinePoolScope block_trampoline_pool(this);
    // We are forced to use 2 instruction sequence since the constant
    // pool pointer is tagged.
    li(dst, Operand::Zero());
    ldx(dst, MemOperand(kConstantPoolRegister, dst));
#else
    lwz(dst, MemOperand(kConstantPoolRegister, 0));
#endif
    return;
  }
#endif

  if (canOptimize) {
    if (is_int16(value)) {
      li(dst, Operand(value));
    } else {
      uint16_t u16;
#if V8_TARGET_ARCH_PPC64
      if (is_int32(value)) {
#endif
        lis(dst, Operand(value >> 16));
#if V8_TARGET_ARCH_PPC64
      } else {
        if (is_int48(value)) {
          li(dst, Operand(value >> 32));
        } else {
          lis(dst, Operand(value >> 48));
          u16 = ((value >> 32) & 0xffff);
          if (u16) {
            ori(dst, dst, Operand(u16));
          }
        }
        sldi(dst, dst, Operand(32));
        u16 = ((value >> 16) & 0xffff);
        if (u16) {
          oris(dst, dst, Operand(u16));
        }
      }
#endif
      u16 = (value & 0xffff);
      if (u16) {
        ori(dst, dst, Operand(u16));
      }
    }
    return;
  }

  DCHECK(!canOptimize);

  {
    BlockTrampolinePoolScope block_trampoline_pool(this);
#if V8_TARGET_ARCH_PPC64
    int32_t hi_32 = static_cast<int32_t>(value >> 32);
    int32_t lo_32 = static_cast<int32_t>(value);
    int hi_word = static_cast<int>(hi_32 >> 16);
    int lo_word = static_cast<int>(hi_32 & 0xffff);
    lis(dst, Operand(SIGN_EXT_IMM16(hi_word)));
    ori(dst, dst, Operand(lo_word));
    sldi(dst, dst, Operand(32));
    hi_word = static_cast<int>(((lo_32 >> 16) & 0xffff));
    lo_word = static_cast<int>(lo_32 & 0xffff);
    oris(dst, dst, Operand(hi_word));
    ori(dst, dst, Operand(lo_word));
#else
    int hi_word = static_cast<int>(value >> 16);
    int lo_word = static_cast<int>(value & 0xffff);
    lis(dst, Operand(SIGN_EXT_IMM16(hi_word)));
    ori(dst, dst, Operand(lo_word));
#endif
  }
}


void Assembler::mov_label_offset(Register dst, Label* label) {
  if (label->is_bound()) {
    int target = label->pos();
    mov(dst, Operand(target + Code::kHeaderSize - kHeapObjectTag));
  } else {
    bool is_linked = label->is_linked();
    // Emit the link to the label in the code stream followed by extra
    // nop instructions.
    DCHECK(dst.is(r3));  // target_at_put assumes r3 for now
    int link = is_linked ? label->pos() - pc_offset() : 0;
    label->link_to(pc_offset());

    if (!is_linked && !trampoline_emitted_) {
      unbound_labels_count_++;
      next_buffer_check_ -= kTrampolineSlotsSize;
    }

    // When the label is bound, these instructions will be patched
    // with a 2 instruction mov sequence that will load the
    // destination register with the position of the label from the
    // beginning of the code.
    //
    // When the label gets bound: target_at extracts the link and
    // target_at_put patches the instructions.
    BlockTrampolinePoolScope block_trampoline_pool(this);
    emit(link);
    nop();
  }
}


// Special register instructions
void Assembler::crxor(int bt, int ba, int bb) {
  emit(EXT1 | CRXOR | bt * B21 | ba * B16 | bb * B11);
}


void Assembler::creqv(int bt, int ba, int bb) {
  emit(EXT1 | CREQV | bt * B21 | ba * B16 | bb * B11);
}


void Assembler::mflr(Register dst) {
  emit(EXT2 | MFSPR | dst.code() * B21 | 256 << 11);  // Ignore RC bit
}


void Assembler::mtlr(Register src) {
  emit(EXT2 | MTSPR | src.code() * B21 | 256 << 11);  // Ignore RC bit
}


void Assembler::mtctr(Register src) {
  emit(EXT2 | MTSPR | src.code() * B21 | 288 << 11);  // Ignore RC bit
}


void Assembler::mtxer(Register src) {
  emit(EXT2 | MTSPR | src.code() * B21 | 32 << 11);
}


void Assembler::mcrfs(int bf, int bfa) {
  emit(EXT4 | MCRFS | bf * B23 | bfa * B18);
}


void Assembler::mfcr(Register dst) { emit(EXT2 | MFCR | dst.code() * B21); }


#if V8_TARGET_ARCH_PPC64
void Assembler::mffprd(Register dst, DoubleRegister src) {
  emit(EXT2 | MFVSRD | src.code() * B21 | dst.code() * B16);
}


void Assembler::mffprwz(Register dst, DoubleRegister src) {
  emit(EXT2 | MFVSRWZ | src.code() * B21 | dst.code() * B16);
}


void Assembler::mtfprd(DoubleRegister dst, Register src) {
  emit(EXT2 | MTVSRD | dst.code() * B21 | src.code() * B16);
}


void Assembler::mtfprwz(DoubleRegister dst, Register src) {
  emit(EXT2 | MTVSRWZ | dst.code() * B21 | src.code() * B16);
}


void Assembler::mtfprwa(DoubleRegister dst, Register src) {
  emit(EXT2 | MTVSRWA | dst.code() * B21 | src.code() * B16);
}
#endif


// Exception-generating instructions and debugging support.
// Stops with a non-negative code less than kNumOfWatchedStops support
// enabling/disabling and a counter feature. See simulator-ppc.h .
void Assembler::stop(const char* msg, Condition cond, int32_t code,
                     CRegister cr) {
  if (cond != al) {
    Label skip;
    b(NegateCondition(cond), &skip, cr);
    bkpt(0);
    bind(&skip);
  } else {
    bkpt(0);
  }
}


void Assembler::bkpt(uint32_t imm16) { emit(0x7d821008); }


void Assembler::info(const char* msg, Condition cond, int32_t code,
                     CRegister cr) {
  if (::v8::internal::FLAG_trace_sim_stubs) {
    emit(0x7d9ff808);
#if V8_TARGET_ARCH_PPC64
    uint64_t value = reinterpret_cast<uint64_t>(msg);
    emit(static_cast<uint32_t>(value >> 32));
    emit(static_cast<uint32_t>(value & 0xFFFFFFFF));
#else
    emit(reinterpret_cast<Instr>(msg));
#endif
  }
}


void Assembler::dcbf(Register ra, Register rb) {
  emit(EXT2 | DCBF | ra.code() * B16 | rb.code() * B11);
}


void Assembler::sync() { emit(EXT2 | SYNC); }


void Assembler::lwsync() { emit(EXT2 | SYNC | 1 * B21); }


void Assembler::icbi(Register ra, Register rb) {
  emit(EXT2 | ICBI | ra.code() * B16 | rb.code() * B11);
}


void Assembler::isync() { emit(EXT1 | ISYNC); }


// Floating point support

void Assembler::lfd(const DoubleRegister frt, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(LFD | frt.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::lfdu(const DoubleRegister frt, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(LFDU | frt.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::lfdx(const DoubleRegister frt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LFDX | frt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lfdux(const DoubleRegister frt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LFDUX | frt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lfs(const DoubleRegister frt, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  DCHECK(!ra.is(r0));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(LFS | frt.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::lfsu(const DoubleRegister frt, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  DCHECK(!ra.is(r0));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(LFSU | frt.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::lfsx(const DoubleRegister frt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LFSX | frt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::lfsux(const DoubleRegister frt, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | LFSUX | frt.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stfd(const DoubleRegister frs, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  DCHECK(!ra.is(r0));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(STFD | frs.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::stfdu(const DoubleRegister frs, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  DCHECK(!ra.is(r0));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(STFDU | frs.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::stfdx(const DoubleRegister frs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STFDX | frs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stfdux(const DoubleRegister frs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STFDUX | frs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stfs(const DoubleRegister frs, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  DCHECK(!ra.is(r0));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(STFS | frs.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::stfsu(const DoubleRegister frs, const MemOperand& src) {
  int offset = src.offset();
  Register ra = src.ra();
  DCHECK(is_int16(offset));
  DCHECK(!ra.is(r0));
  int imm16 = offset & kImm16Mask;
  // could be x_form instruction with some casting magic
  emit(STFSU | frs.code() * B21 | ra.code() * B16 | imm16);
}


void Assembler::stfsx(const DoubleRegister frs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STFSX | frs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::stfsux(const DoubleRegister frs, const MemOperand& src) {
  Register ra = src.ra();
  Register rb = src.rb();
  DCHECK(!ra.is(r0));
  emit(EXT2 | STFSUX | frs.code() * B21 | ra.code() * B16 | rb.code() * B11 |
       LeaveRC);
}


void Assembler::fsub(const DoubleRegister frt, const DoubleRegister fra,
                     const DoubleRegister frb, RCBit rc) {
  a_form(EXT4 | FSUB, frt, fra, frb, rc);
}


void Assembler::fadd(const DoubleRegister frt, const DoubleRegister fra,
                     const DoubleRegister frb, RCBit rc) {
  a_form(EXT4 | FADD, frt, fra, frb, rc);
}


void Assembler::fmul(const DoubleRegister frt, const DoubleRegister fra,
                     const DoubleRegister frc, RCBit rc) {
  emit(EXT4 | FMUL | frt.code() * B21 | fra.code() * B16 | frc.code() * B6 |
       rc);
}


void Assembler::fdiv(const DoubleRegister frt, const DoubleRegister fra,
                     const DoubleRegister frb, RCBit rc) {
  a_form(EXT4 | FDIV, frt, fra, frb, rc);
}


void Assembler::fcmpu(const DoubleRegister fra, const DoubleRegister frb,
                      CRegister cr) {
  DCHECK(cr.code() >= 0 && cr.code() <= 7);
  emit(EXT4 | FCMPU | cr.code() * B23 | fra.code() * B16 | frb.code() * B11);
}


void Assembler::fmr(const DoubleRegister frt, const DoubleRegister frb,
                    RCBit rc) {
  emit(EXT4 | FMR | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fctiwz(const DoubleRegister frt, const DoubleRegister frb) {
  emit(EXT4 | FCTIWZ | frt.code() * B21 | frb.code() * B11);
}


void Assembler::fctiw(const DoubleRegister frt, const DoubleRegister frb) {
  emit(EXT4 | FCTIW | frt.code() * B21 | frb.code() * B11);
}


void Assembler::frim(const DoubleRegister frt, const DoubleRegister frb) {
  emit(EXT4 | FRIM | frt.code() * B21 | frb.code() * B11);
}


void Assembler::frsp(const DoubleRegister frt, const DoubleRegister frb,
                     RCBit rc) {
  emit(EXT4 | FRSP | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fcfid(const DoubleRegister frt, const DoubleRegister frb,
                      RCBit rc) {
  emit(EXT4 | FCFID | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fctid(const DoubleRegister frt, const DoubleRegister frb,
                      RCBit rc) {
  emit(EXT4 | FCTID | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fctidz(const DoubleRegister frt, const DoubleRegister frb,
                       RCBit rc) {
  emit(EXT4 | FCTIDZ | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fsel(const DoubleRegister frt, const DoubleRegister fra,
                     const DoubleRegister frc, const DoubleRegister frb,
                     RCBit rc) {
  emit(EXT4 | FSEL | frt.code() * B21 | fra.code() * B16 | frb.code() * B11 |
       frc.code() * B6 | rc);
}


void Assembler::fneg(const DoubleRegister frt, const DoubleRegister frb,
                     RCBit rc) {
  emit(EXT4 | FNEG | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::mtfsfi(int bf, int immediate, RCBit rc) {
  emit(EXT4 | MTFSFI | bf * B23 | immediate * B12 | rc);
}


void Assembler::mffs(const DoubleRegister frt, RCBit rc) {
  emit(EXT4 | MFFS | frt.code() * B21 | rc);
}


void Assembler::mtfsf(const DoubleRegister frb, bool L, int FLM, bool W,
                      RCBit rc) {
  emit(EXT4 | MTFSF | frb.code() * B11 | W * B16 | FLM * B17 | L * B25 | rc);
}


void Assembler::fsqrt(const DoubleRegister frt, const DoubleRegister frb,
                      RCBit rc) {
  emit(EXT4 | FSQRT | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fabs(const DoubleRegister frt, const DoubleRegister frb,
                     RCBit rc) {
  emit(EXT4 | FABS | frt.code() * B21 | frb.code() * B11 | rc);
}


void Assembler::fmadd(const DoubleRegister frt, const DoubleRegister fra,
                      const DoubleRegister frc, const DoubleRegister frb,
                      RCBit rc) {
  emit(EXT4 | FMADD | frt.code() * B21 | fra.code() * B16 | frb.code() * B11 |
       frc.code() * B6 | rc);
}


void Assembler::fmsub(const DoubleRegister frt, const DoubleRegister fra,
                      const DoubleRegister frc, const DoubleRegister frb,
                      RCBit rc) {
  emit(EXT4 | FMSUB | frt.code() * B21 | fra.code() * B16 | frb.code() * B11 |
       frc.code() * B6 | rc);
}


// Pseudo instructions.
void Assembler::nop(int type) {
  Register reg = r0;
  switch (type) {
    case NON_MARKING_NOP:
      reg = r0;
      break;
    case GROUP_ENDING_NOP:
      reg = r2;
      break;
    case DEBUG_BREAK_NOP:
      reg = r3;
      break;
    default:
      UNIMPLEMENTED();
  }

  ori(reg, reg, Operand::Zero());
}


bool Assembler::IsNop(Instr instr, int type) {
  int reg = 0;
  switch (type) {
    case NON_MARKING_NOP:
      reg = 0;
      break;
    case GROUP_ENDING_NOP:
      reg = 2;
      break;
    case DEBUG_BREAK_NOP:
      reg = 3;
      break;
    default:
      UNIMPLEMENTED();
  }
  return instr == (ORI | reg * B21 | reg * B16);
}


// Debugging.
void Assembler::RecordJSReturn() {
  positions_recorder()->WriteRecordedPositions();
  CheckBuffer();
  RecordRelocInfo(RelocInfo::JS_RETURN);
}


void Assembler::RecordDebugBreakSlot() {
  positions_recorder()->WriteRecordedPositions();
  CheckBuffer();
  RecordRelocInfo(RelocInfo::DEBUG_BREAK_SLOT);
}


void Assembler::RecordComment(const char* msg) {
  if (FLAG_code_comments) {
    CheckBuffer();
    RecordRelocInfo(RelocInfo::COMMENT, reinterpret_cast<intptr_t>(msg));
  }
}


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

  // Set up 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.
  intptr_t pc_delta = desc.buffer - buffer_;
  intptr_t 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.

#if ABI_USES_FUNCTION_DESCRIPTORS || V8_OOL_CONSTANT_POOL
  // Relocate runtime entries.
  for (RelocIterator it(desc); !it.done(); it.next()) {
    RelocInfo::Mode rmode = it.rinfo()->rmode();
    if (rmode == RelocInfo::INTERNAL_REFERENCE) {
      RelocateInternalReference(it.rinfo()->pc(), pc_delta, 0);
    }
  }
#if V8_OOL_CONSTANT_POOL
  constant_pool_builder_.Relocate(pc_delta);
#endif
#endif
}


void Assembler::db(uint8_t data) {
  CheckBuffer();
  *reinterpret_cast<uint8_t*>(pc_) = data;
  pc_ += sizeof(uint8_t);
}


void Assembler::dd(uint32_t data) {
  CheckBuffer();
  *reinterpret_cast<uint32_t*>(pc_) = data;
  pc_ += sizeof(uint32_t);
}


void Assembler::emit_ptr(uintptr_t data) {
  CheckBuffer();
  *reinterpret_cast<uintptr_t*>(pc_) = data;
  pc_ += sizeof(uintptr_t);
}


void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
  RelocInfo rinfo(pc_, rmode, data, NULL);
  RecordRelocInfo(rinfo);
}


void Assembler::RecordRelocInfo(const RelocInfo& rinfo) {
  if (rinfo.rmode() >= RelocInfo::JS_RETURN &&
      rinfo.rmode() <= RelocInfo::DEBUG_BREAK_SLOT) {
    // Adjust code for new modes.
    DCHECK(RelocInfo::IsDebugBreakSlot(rinfo.rmode()) ||
           RelocInfo::IsJSReturn(rinfo.rmode()) ||
           RelocInfo::IsComment(rinfo.rmode()) ||
           RelocInfo::IsPosition(rinfo.rmode()));
  }
  if (!RelocInfo::IsNone(rinfo.rmode())) {
    // Don't record external references unless the heap will be serialized.
    if (rinfo.rmode() == RelocInfo::EXTERNAL_REFERENCE) {
      if (!serializer_enabled() && !emit_debug_code()) {
        return;
      }
    }
    DCHECK(buffer_space() >= kMaxRelocSize);  // too late to grow buffer here
    if (rinfo.rmode() == RelocInfo::CODE_TARGET_WITH_ID) {
      RelocInfo reloc_info_with_ast_id(rinfo.pc(), rinfo.rmode(),
                                       RecordedAstId().ToInt(), NULL);
      ClearRecordedAstId();
      reloc_info_writer.Write(&reloc_info_with_ast_id);
    } else {
      reloc_info_writer.Write(&rinfo);
    }
  }
}


void Assembler::BlockTrampolinePoolFor(int instructions) {
  BlockTrampolinePoolBefore(pc_offset() + instructions * kInstrSize);
}


void Assembler::CheckTrampolinePool() {
  // Some small sequences of instructions must not be broken up by the
  // insertion of a trampoline pool; such sequences are protected by setting
  // either trampoline_pool_blocked_nesting_ or no_trampoline_pool_before_,
  // which are both checked here. Also, recursive calls to CheckTrampolinePool
  // are blocked by trampoline_pool_blocked_nesting_.
  if ((trampoline_pool_blocked_nesting_ > 0) ||
      (pc_offset() < no_trampoline_pool_before_)) {
    // Emission is currently blocked; make sure we try again as soon as
    // possible.
    if (trampoline_pool_blocked_nesting_ > 0) {
      next_buffer_check_ = pc_offset() + kInstrSize;
    } else {
      next_buffer_check_ = no_trampoline_pool_before_;
    }
    return;
  }

  DCHECK(!trampoline_emitted_);
  DCHECK(unbound_labels_count_ >= 0);
  if (unbound_labels_count_ > 0) {
    // First we emit jump, then we emit trampoline pool.
    {
      BlockTrampolinePoolScope block_trampoline_pool(this);
      Label after_pool;
      b(&after_pool);

      int pool_start = pc_offset();
      for (int i = 0; i < unbound_labels_count_; i++) {
        b(&after_pool);
      }
      bind(&after_pool);
      trampoline_ = Trampoline(pool_start, unbound_labels_count_);

      trampoline_emitted_ = true;
      // As we are only going to emit trampoline once, we need to prevent any
      // further emission.
      next_buffer_check_ = kMaxInt;
    }
  } else {
    // Number of branches to unbound label at this point is zero, so we can
    // move next buffer check to maximum.
    next_buffer_check_ =
        pc_offset() + kMaxCondBranchReach - kMaxBlockTrampolineSectionSize;
  }
  return;
}


Handle<ConstantPoolArray> Assembler::NewConstantPool(Isolate* isolate) {
#if V8_OOL_CONSTANT_POOL
  return constant_pool_builder_.New(isolate);
#else
  // No out-of-line constant pool support.
  DCHECK(!FLAG_enable_ool_constant_pool);
  return isolate->factory()->empty_constant_pool_array();
#endif
}


void Assembler::PopulateConstantPool(ConstantPoolArray* constant_pool) {
#if V8_OOL_CONSTANT_POOL
  constant_pool_builder_.Populate(this, constant_pool);
#else
  // No out-of-line constant pool support.
  DCHECK(!FLAG_enable_ool_constant_pool);
#endif
}


#if V8_OOL_CONSTANT_POOL
ConstantPoolBuilder::ConstantPoolBuilder()
    : size_(0),
      entries_(),
      current_section_(ConstantPoolArray::SMALL_SECTION) {}


bool ConstantPoolBuilder::IsEmpty() { return entries_.size() == 0; }


ConstantPoolArray::Type ConstantPoolBuilder::GetConstantPoolType(
    RelocInfo::Mode rmode) {
#if V8_TARGET_ARCH_PPC64
  // We don't support 32-bit entries at this time.
  if (!RelocInfo::IsGCRelocMode(rmode)) {
    return ConstantPoolArray::INT64;
#else
  if (rmode == RelocInfo::NONE64) {
    return ConstantPoolArray::INT64;
  } else if (!RelocInfo::IsGCRelocMode(rmode)) {
    return ConstantPoolArray::INT32;
#endif
  } else if (RelocInfo::IsCodeTarget(rmode)) {
    return ConstantPoolArray::CODE_PTR;
  } else {
    DCHECK(RelocInfo::IsGCRelocMode(rmode) && !RelocInfo::IsCodeTarget(rmode));
    return ConstantPoolArray::HEAP_PTR;
  }
}


ConstantPoolArray::LayoutSection ConstantPoolBuilder::AddEntry(
    Assembler* assm, const RelocInfo& rinfo) {
  RelocInfo::Mode rmode = rinfo.rmode();
  DCHECK(rmode != RelocInfo::COMMENT && rmode != RelocInfo::POSITION &&
         rmode != RelocInfo::STATEMENT_POSITION &&
         rmode != RelocInfo::CONST_POOL);

  // Try to merge entries which won't be patched.
  int merged_index = -1;
  ConstantPoolArray::LayoutSection entry_section = current_section_;
  if (RelocInfo::IsNone(rmode) ||
      (!assm->serializer_enabled() && (rmode >= RelocInfo::CELL))) {
    size_t i;
    std::vector<ConstantPoolEntry>::const_iterator it;
    for (it = entries_.begin(), i = 0; it != entries_.end(); it++, i++) {
      if (RelocInfo::IsEqual(rinfo, it->rinfo_)) {
        // Merge with found entry.
        merged_index = i;
        entry_section = entries_[i].section_;
        break;
      }
    }
  }
  DCHECK(entry_section <= current_section_);
  entries_.push_back(ConstantPoolEntry(rinfo, entry_section, merged_index));

  if (merged_index == -1) {
    // Not merged, so update the appropriate count.
    number_of_entries_[entry_section].increment(GetConstantPoolType(rmode));
  }

  // Check if we still have room for another entry in the small section
  // given the limitations of the header's layout fields.
  if (current_section_ == ConstantPoolArray::SMALL_SECTION) {
    size_ = ConstantPoolArray::SizeFor(*small_entries());
    if (!is_uint12(size_)) {
      current_section_ = ConstantPoolArray::EXTENDED_SECTION;
    }
  } else {
    size_ = ConstantPoolArray::SizeForExtended(*small_entries(),
                                               *extended_entries());
  }

  return entry_section;
}


void ConstantPoolBuilder::Relocate(intptr_t pc_delta) {
  for (std::vector<ConstantPoolEntry>::iterator entry = entries_.begin();
       entry != entries_.end(); entry++) {
    DCHECK(entry->rinfo_.rmode() != RelocInfo::JS_RETURN);
    entry->rinfo_.set_pc(entry->rinfo_.pc() + pc_delta);
  }
}


Handle<ConstantPoolArray> ConstantPoolBuilder::New(Isolate* isolate) {
  if (IsEmpty()) {
    return isolate->factory()->empty_constant_pool_array();
  } else if (extended_entries()->is_empty()) {
    return isolate->factory()->NewConstantPoolArray(*small_entries());
  } else {
    DCHECK(current_section_ == ConstantPoolArray::EXTENDED_SECTION);
    return isolate->factory()->NewExtendedConstantPoolArray(
        *small_entries(), *extended_entries());
  }
}


void ConstantPoolBuilder::Populate(Assembler* assm,
                                   ConstantPoolArray* constant_pool) {
  DCHECK_EQ(extended_entries()->is_empty(),
            !constant_pool->is_extended_layout());
  DCHECK(small_entries()->equals(ConstantPoolArray::NumberOfEntries(
      constant_pool, ConstantPoolArray::SMALL_SECTION)));
  if (constant_pool->is_extended_layout()) {
    DCHECK(extended_entries()->equals(ConstantPoolArray::NumberOfEntries(
        constant_pool, ConstantPoolArray::EXTENDED_SECTION)));
  }

  // Set up initial offsets.
  int offsets[ConstantPoolArray::NUMBER_OF_LAYOUT_SECTIONS]
             [ConstantPoolArray::NUMBER_OF_TYPES];
  for (int section = 0; section <= constant_pool->final_section(); section++) {
    int section_start = (section == ConstantPoolArray::EXTENDED_SECTION)
                            ? small_entries()->total_count()
                            : 0;
    for (int i = 0; i < ConstantPoolArray::NUMBER_OF_TYPES; i++) {
      ConstantPoolArray::Type type = static_cast<ConstantPoolArray::Type>(i);
      if (number_of_entries_[section].count_of(type) != 0) {
        offsets[section][type] = constant_pool->OffsetOfElementAt(
            number_of_entries_[section].base_of(type) + section_start);
      }
    }
  }

  for (std::vector<ConstantPoolEntry>::iterator entry = entries_.begin();
       entry != entries_.end(); entry++) {
    RelocInfo rinfo = entry->rinfo_;
    RelocInfo::Mode rmode = entry->rinfo_.rmode();
    ConstantPoolArray::Type type = GetConstantPoolType(rmode);

    // Update constant pool if necessary and get the entry's offset.
    int offset;
    if (entry->merged_index_ == -1) {
      offset = offsets[entry->section_][type];
      offsets[entry->section_][type] += ConstantPoolArray::entry_size(type);
      if (type == ConstantPoolArray::INT64) {
#if V8_TARGET_ARCH_PPC64
        constant_pool->set_at_offset(offset, rinfo.data());
#else
        constant_pool->set_at_offset(offset, rinfo.data64());
      } else if (type == ConstantPoolArray::INT32) {
        constant_pool->set_at_offset(offset,
                                     static_cast<int32_t>(rinfo.data()));
#endif
      } else if (type == ConstantPoolArray::CODE_PTR) {
        constant_pool->set_at_offset(offset,
                                     reinterpret_cast<Address>(rinfo.data()));
      } else {
        DCHECK(type == ConstantPoolArray::HEAP_PTR);
        constant_pool->set_at_offset(offset,
                                     reinterpret_cast<Object*>(rinfo.data()));
      }
      offset -= kHeapObjectTag;
      entry->merged_index_ = offset;  // Stash offset for merged entries.
    } else {
      DCHECK(entry->merged_index_ < (entry - entries_.begin()));
      offset = entries_[entry->merged_index_].merged_index_;
    }

    // Patch load instruction with correct offset.
    Assembler::SetConstantPoolOffset(rinfo.pc(), offset);
  }
}
#endif
}
}  // namespace v8::internal

#endif  // V8_TARGET_ARCH_PPC