Experimental parser: merge to r19637

src/a64/assembler-a64.cc

+// Copyright 2013 the V8 project authors. 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.
+//     * Redistributions 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 Google Inc. nor the names of its
+//       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.
+
+#include "v8.h"
+
+#if V8_TARGET_ARCH_A64
+
+#define A64_DEFINE_REG_STATICS
+
+#include "a64/assembler-a64-inl.h"
+
+namespace v8 {
+namespace internal {
+
+
+// -----------------------------------------------------------------------------
+// CpuFeatures utilities (for V8 compatibility).
+
+ExternalReference ExternalReference::cpu_features() {
+  return ExternalReference(&CpuFeatures::supported_);
+}
+
+
+// -----------------------------------------------------------------------------
+// CPURegList utilities.
+
+CPURegister CPURegList::PopLowestIndex() {
+  ASSERT(IsValid());
+  if (IsEmpty()) {
+    return NoCPUReg;
+  }
+  int index = CountTrailingZeros(list_, kRegListSizeInBits);
+  ASSERT((1 << index) & list_);
+  Remove(index);
+  return CPURegister::Create(index, size_, type_);
+}
+
+
+CPURegister CPURegList::PopHighestIndex() {
+  ASSERT(IsValid());
+  if (IsEmpty()) {
+    return NoCPUReg;
+  }
+  int index = CountLeadingZeros(list_, kRegListSizeInBits);
+  index = kRegListSizeInBits - 1 - index;
+  ASSERT((1 << index) & list_);
+  Remove(index);
+  return CPURegister::Create(index, size_, type_);
+}
+
+
+void CPURegList::RemoveCalleeSaved() {
+  if (type() == CPURegister::kRegister) {
+    Remove(GetCalleeSaved(RegisterSizeInBits()));
+  } else if (type() == CPURegister::kFPRegister) {
+    Remove(GetCalleeSavedFP(RegisterSizeInBits()));
+  } else {
+    ASSERT(type() == CPURegister::kNoRegister);
+    ASSERT(IsEmpty());
+    // The list must already be empty, so do nothing.
+  }
+}
+
+
+CPURegList CPURegList::GetCalleeSaved(unsigned size) {
+  return CPURegList(CPURegister::kRegister, size, 19, 29);
+}
+
+
+CPURegList CPURegList::GetCalleeSavedFP(unsigned size) {
+  return CPURegList(CPURegister::kFPRegister, size, 8, 15);
+}
+
+
+CPURegList CPURegList::GetCallerSaved(unsigned size) {
+  // Registers x0-x18 and lr (x30) are caller-saved.
+  CPURegList list = CPURegList(CPURegister::kRegister, size, 0, 18);
+  list.Combine(lr);
+  return list;
+}
+
+
+CPURegList CPURegList::GetCallerSavedFP(unsigned size) {
+  // Registers d0-d7 and d16-d31 are caller-saved.
+  CPURegList list = CPURegList(CPURegister::kFPRegister, size, 0, 7);
+  list.Combine(CPURegList(CPURegister::kFPRegister, size, 16, 31));
+  return list;
+}
+
+
+// This function defines the list of registers which are associated with a
+// safepoint slot. Safepoint register slots are saved contiguously on the stack.
+// MacroAssembler::SafepointRegisterStackIndex handles mapping from register
+// code to index in the safepoint register slots. Any change here can affect
+// this mapping.
+CPURegList CPURegList::GetSafepointSavedRegisters() {
+  CPURegList list = CPURegList::GetCalleeSaved();
+  list.Combine(CPURegList(CPURegister::kRegister, kXRegSize, kJSCallerSaved));
+
+  // Note that unfortunately we can't use symbolic names for registers and have
+  // to directly use register codes. This is because this function is used to
+  // initialize some static variables and we can't rely on register variables
+  // to be initialized due to static initialization order issues in C++.
+
+  // Drop ip0 and ip1 (i.e. x16 and x17), as they should not be expected to be
+  // preserved outside of the macro assembler.
+  list.Remove(16);
+  list.Remove(17);
+
+  // Add x18 to the safepoint list, as although it's not in kJSCallerSaved, it
+  // is a caller-saved register according to the procedure call standard.
+  list.Combine(18);
+
+  // Drop jssp as the stack pointer doesn't need to be included.
+  list.Remove(28);
+
+  // Add the link register (x30) to the safepoint list.
+  list.Combine(30);
+
+  return list;
+}
+
+
+// -----------------------------------------------------------------------------
+// Implementation of RelocInfo
+
+const int RelocInfo::kApplyMask = 0;
+
+
+bool RelocInfo::IsCodedSpecially() {
+  // The deserializer needs to know whether a pointer is specially coded. Being
+  // specially coded on A64 means that it is a movz/movk sequence. We don't
+  // generate those for relocatable pointers.
+  return false;
+}
+
+
+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.
+  CPU::FlushICache(pc_, instruction_count * kInstructionSize);
+}
+
+
+// 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) {
+  UNIMPLEMENTED();
+}
+
+
+Register GetAllocatableRegisterThatIsNotOneOf(Register reg1, Register reg2,
+                                              Register reg3, Register reg4) {
+  CPURegList regs(reg1, reg2, reg3, reg4);
+  for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {
+    Register candidate = Register::FromAllocationIndex(i);
+    if (regs.IncludesAliasOf(candidate)) continue;
+    return candidate;
+  }
+  UNREACHABLE();
+  return NoReg;
+}
+
+
+bool AreAliased(const CPURegister& reg1, const CPURegister& reg2,
+                const CPURegister& reg3, const CPURegister& reg4,
+                const CPURegister& reg5, const CPURegister& reg6,
+                const CPURegister& reg7, const CPURegister& reg8) {
+  int number_of_valid_regs = 0;
+  int number_of_valid_fpregs = 0;
+
+  RegList unique_regs = 0;
+  RegList unique_fpregs = 0;
+
+  const CPURegister regs[] = {reg1, reg2, reg3, reg4, reg5, reg6, reg7, reg8};
+
+  for (unsigned i = 0; i < sizeof(regs) / sizeof(regs[0]); i++) {
+    if (regs[i].IsRegister()) {
+      number_of_valid_regs++;
+      unique_regs |= regs[i].Bit();
+    } else if (regs[i].IsFPRegister()) {
+      number_of_valid_fpregs++;
+      unique_fpregs |= regs[i].Bit();
+    } else {
+      ASSERT(!regs[i].IsValid());
+    }
+  }
+
+  int number_of_unique_regs =
+    CountSetBits(unique_regs, sizeof(unique_regs) * kBitsPerByte);
+  int number_of_unique_fpregs =
+    CountSetBits(unique_fpregs, sizeof(unique_fpregs) * kBitsPerByte);
+
+  ASSERT(number_of_valid_regs >= number_of_unique_regs);
+  ASSERT(number_of_valid_fpregs >= number_of_unique_fpregs);
+
+  return (number_of_valid_regs != number_of_unique_regs) ||
+         (number_of_valid_fpregs != number_of_unique_fpregs);
+}
+
+
+bool AreSameSizeAndType(const CPURegister& reg1, const CPURegister& reg2,
+                        const CPURegister& reg3, const CPURegister& reg4,
+                        const CPURegister& reg5, const CPURegister& reg6,
+                        const CPURegister& reg7, const CPURegister& reg8) {
+  ASSERT(reg1.IsValid());
+  bool match = true;
+  match &= !reg2.IsValid() || reg2.IsSameSizeAndType(reg1);
+  match &= !reg3.IsValid() || reg3.IsSameSizeAndType(reg1);
+  match &= !reg4.IsValid() || reg4.IsSameSizeAndType(reg1);
+  match &= !reg5.IsValid() || reg5.IsSameSizeAndType(reg1);
+  match &= !reg6.IsValid() || reg6.IsSameSizeAndType(reg1);
+  match &= !reg7.IsValid() || reg7.IsSameSizeAndType(reg1);
+  match &= !reg8.IsValid() || reg8.IsSameSizeAndType(reg1);
+  return match;
+}
+
+
+void Operand::initialize_handle(Handle<Object> handle) {
+  AllowDeferredHandleDereference using_raw_address;
+
+  // Verify all Objects referred by code are NOT in new space.
+  Object* obj = *handle;
+  if (obj->IsHeapObject()) {
+    ASSERT(!HeapObject::cast(obj)->GetHeap()->InNewSpace(obj));
+    immediate_ = reinterpret_cast<intptr_t>(handle.location());
+    rmode_ = RelocInfo::EMBEDDED_OBJECT;
+  } else {
+    STATIC_ASSERT(sizeof(intptr_t) == sizeof(int64_t));
+    immediate_ = reinterpret_cast<intptr_t>(obj);
+    rmode_ = RelocInfo::NONE64;
+  }
+}
+
+
+bool Operand::NeedsRelocation() const {
+  if (rmode_ == RelocInfo::EXTERNAL_REFERENCE) {
+#ifdef DEBUG
+    if (!Serializer::enabled()) {
+      Serializer::TooLateToEnableNow();
+    }
+#endif
+    return Serializer::enabled();
+  }
+
+  return !RelocInfo::IsNone(rmode_);
+}
+
+
+// Assembler
+
+Assembler::Assembler(Isolate* isolate, void* buffer, int buffer_size)
+    : AssemblerBase(isolate, buffer, buffer_size),
+      recorded_ast_id_(TypeFeedbackId::None()),
+      unresolved_branches_(),
+      positions_recorder_(this) {
+  const_pool_blocked_nesting_ = 0;
+  Reset();
+}
+
+
+Assembler::~Assembler() {
+  ASSERT(num_pending_reloc_info_ == 0);
+  ASSERT(const_pool_blocked_nesting_ == 0);
+}
+
+
+void Assembler::Reset() {
+#ifdef DEBUG
+  ASSERT((pc_ >= buffer_) && (pc_ < buffer_ + buffer_size_));
+  ASSERT(const_pool_blocked_nesting_ == 0);
+  memset(buffer_, 0, pc_ - buffer_);
+#endif
+  pc_ = buffer_;
+  reloc_info_writer.Reposition(reinterpret_cast<byte*>(buffer_ + buffer_size_),
+                               reinterpret_cast<byte*>(pc_));
+  num_pending_reloc_info_ = 0;
+  next_buffer_check_ = 0;
+  no_const_pool_before_ = 0;
+  first_const_pool_use_ = -1;
+  ClearRecordedAstId();
+}
+
+
+void Assembler::GetCode(CodeDesc* desc) {
+  // Emit constant pool if necessary.
+  CheckConstPool(true, false);
+  ASSERT(num_pending_reloc_info_ == 0);
+
+  // Set up code descriptor.
+  if (desc) {
+    desc->buffer = reinterpret_cast<byte*>(buffer_);
+    desc->buffer_size = buffer_size_;
+    desc->instr_size = pc_offset();
+    desc->reloc_size = (reinterpret_cast<byte*>(buffer_) + buffer_size_) -
+                       reloc_info_writer.pos();
+    desc->origin = this;
+  }
+}
+
+
+void Assembler::Align(int m) {
+  ASSERT(m >= 4 && IsPowerOf2(m));
+  while ((pc_offset() & (m - 1)) != 0) {
+    nop();
+  }
+}
+
+
+void Assembler::CheckLabelLinkChain(Label const * label) {
+#ifdef DEBUG
+  if (label->is_linked()) {
+    int linkoffset = label->pos();
+    bool end_of_chain = false;
+    while (!end_of_chain) {
+      Instruction * link = InstructionAt(linkoffset);
+      int linkpcoffset = link->ImmPCOffset();
+      int prevlinkoffset = linkoffset + linkpcoffset;
+
+      end_of_chain = (linkoffset == prevlinkoffset);
+      linkoffset = linkoffset + linkpcoffset;
+    }
+  }
+#endif
+}
+
+
+void Assembler::RemoveBranchFromLabelLinkChain(Instruction* branch,
+                                               Label* label,
+                                               Instruction* label_veneer) {
+  ASSERT(label->is_linked());
+
+  CheckLabelLinkChain(label);
+
+  Instruction* link = InstructionAt(label->pos());
+  Instruction* prev_link = link;
+  Instruction* next_link;
+  bool end_of_chain = false;
+
+  while (link != branch && !end_of_chain) {
+    next_link = link->ImmPCOffsetTarget();
+    end_of_chain = (link == next_link);
+    prev_link = link;
+    link = next_link;
+  }
+
+  ASSERT(branch == link);
+  next_link = branch->ImmPCOffsetTarget();
+
+  if (branch == prev_link) {
+    // The branch is the first instruction in the chain.
+    if (branch == next_link) {
+      // It is also the last instruction in the chain, so it is the only branch
+      // currently referring to this label.
+      label->Unuse();
+    } else {
+      label->link_to(reinterpret_cast<byte*>(next_link) - buffer_);
+    }
+
+  } else if (branch == next_link) {
+    // The branch is the last (but not also the first) instruction in the chain.
+    prev_link->SetImmPCOffsetTarget(prev_link);
+
+  } else {
+    // The branch is in the middle of the chain.
+    if (prev_link->IsTargetInImmPCOffsetRange(next_link)) {
+      prev_link->SetImmPCOffsetTarget(next_link);
+    } else if (label_veneer != NULL) {
+      // Use the veneer for all previous links in the chain.
+      prev_link->SetImmPCOffsetTarget(prev_link);
+
+      end_of_chain = false;
+      link = next_link;
+      while (!end_of_chain) {
+        next_link = link->ImmPCOffsetTarget();
+        end_of_chain = (link == next_link);
+        link->SetImmPCOffsetTarget(label_veneer);
+        link = next_link;
+      }
+    } else {
+      // The assert below will fire.
+      // Some other work could be attempted to fix up the chain, but it would be
+      // rather complicated. If we crash here, we may want to consider using an
+      // other mechanism than a chain of branches.
+      //
+      // Note that this situation currently should not happen, as we always call
+      // this function with a veneer to the target label.
+      // However this could happen with a MacroAssembler in the following state:
+      //    [previous code]
+      //    B(label);
+      //    [20KB code]
+      //    Tbz(label);   // First tbz. Pointing to unconditional branch.
+      //    [20KB code]
+      //    Tbz(label);   // Second tbz. Pointing to the first tbz.
+      //    [more code]
+      // and this function is called to remove the first tbz from the label link
+      // chain. Since tbz has a range of +-32KB, the second tbz cannot point to
+      // the unconditional branch.
+      CHECK(prev_link->IsTargetInImmPCOffsetRange(next_link));
+      UNREACHABLE();
+    }
+  }
+
+  CheckLabelLinkChain(label);
+}
+
+
+void Assembler::bind(Label* label) {
+  // Bind label to the address at pc_. All instructions (most likely branches)
+  // that are linked to this label will be updated to point to the newly-bound
+  // label.
+
+  ASSERT(!label->is_near_linked());
+  ASSERT(!label->is_bound());
+
+  // If the label is linked, the link chain looks something like this:
+  //
+  // |--I----I-------I-------L
+  // |---------------------->| pc_offset
+  // |-------------->|         linkoffset = label->pos()
+  //         |<------|         link->ImmPCOffset()
+  // |------>|                 prevlinkoffset = linkoffset + link->ImmPCOffset()
+  //
+  // On each iteration, the last link is updated and then removed from the
+  // chain until only one remains. At that point, the label is bound.
+  //
+  // If the label is not linked, no preparation is required before binding.
+  while (label->is_linked()) {
+    int linkoffset = label->pos();
+    Instruction* link = InstructionAt(linkoffset);
+    int prevlinkoffset = linkoffset + link->ImmPCOffset();
+
+    CheckLabelLinkChain(label);
+
+    ASSERT(linkoffset >= 0);
+    ASSERT(linkoffset < pc_offset());
+    ASSERT((linkoffset > prevlinkoffset) ||
+           (linkoffset - prevlinkoffset == kStartOfLabelLinkChain));
+    ASSERT(prevlinkoffset >= 0);
+
+    // Update the link to point to the label.
+    link->SetImmPCOffsetTarget(reinterpret_cast<Instruction*>(pc_));
+
+    // Link the label to the previous link in the chain.
+    if (linkoffset - prevlinkoffset == kStartOfLabelLinkChain) {
+      // We hit kStartOfLabelLinkChain, so the chain is fully processed.
+      label->Unuse();
+    } else {
+      // Update the label for the next iteration.
+      label->link_to(prevlinkoffset);
+    }
+  }
+  label->bind_to(pc_offset());
+
+  ASSERT(label->is_bound());
+  ASSERT(!label->is_linked());
+
+  DeleteUnresolvedBranchInfoForLabel(label);
+}
+
+
+int Assembler::LinkAndGetByteOffsetTo(Label* label) {
+  ASSERT(sizeof(*pc_) == 1);
+  CheckLabelLinkChain(label);
+
+  int offset;
+  if (label->is_bound()) {
+    // The label is bound, so it does not need to be updated. Referring
+    // instructions must link directly to the label as they will not be
+    // updated.
+    //
+    // In this case, label->pos() returns the offset of the label from the
+    // start of the buffer.
+    //
+    // Note that offset can be zero for self-referential instructions. (This
+    // could be useful for ADR, for example.)
+    offset = label->pos() - pc_offset();
+    ASSERT(offset <= 0);
+  } else {
+    if (label->is_linked()) {
+      // The label is linked, so the referring instruction should be added onto
+      // the end of the label's link chain.
+      //
+      // In this case, label->pos() returns the offset of the last linked
+      // instruction from the start of the buffer.
+      offset = label->pos() - pc_offset();
+      ASSERT(offset != kStartOfLabelLinkChain);
+      // Note that the offset here needs to be PC-relative only so that the
+      // first instruction in a buffer can link to an unbound label. Otherwise,
+      // the offset would be 0 for this case, and 0 is reserved for
+      // kStartOfLabelLinkChain.
+    } else {
+      // The label is unused, so it now becomes linked and the referring
+      // instruction is at the start of the new link chain.
+      offset = kStartOfLabelLinkChain;
+    }
+    // The instruction at pc is now the last link in the label's chain.
+    label->link_to(pc_offset());
+  }
+
+  return offset;
+}
+
+
+void Assembler::DeleteUnresolvedBranchInfoForLabel(Label* label) {
+  // Branches to this label will be resolved when the label is bound below.
+  std::multimap<int, FarBranchInfo>::iterator it_tmp, it;
+  it = unresolved_branches_.begin();
+  while (it != unresolved_branches_.end()) {
+    it_tmp = it++;
+    if (it_tmp->second.label_ == label) {
+      CHECK(it_tmp->first >= pc_offset());
+      unresolved_branches_.erase(it_tmp);
+    }
+  }
+}
+
+
+void Assembler::StartBlockConstPool() {
+  if (const_pool_blocked_nesting_++ == 0) {
+    // Prevent constant pool checks happening by setting the next check to
+    // the biggest possible offset.
+    next_buffer_check_ = kMaxInt;
+  }
+}
+
+
+void Assembler::EndBlockConstPool() {
+  if (--const_pool_blocked_nesting_ == 0) {
+    // Check the constant pool hasn't been blocked for too long.
+    ASSERT((num_pending_reloc_info_ == 0) ||
+           (pc_offset() < (first_const_pool_use_ + kMaxDistToPool)));
+    // Two cases:
+    //  * no_const_pool_before_ >= next_buffer_check_ and the emission is
+    //    still blocked
+    //  * no_const_pool_before_ < next_buffer_check_ and the next emit will
+    //    trigger a check.
+    next_buffer_check_ = no_const_pool_before_;
+  }
+}
+
+
+bool Assembler::is_const_pool_blocked() const {
+  return (const_pool_blocked_nesting_ > 0) ||
+         (pc_offset() < no_const_pool_before_);
+}
+
+
+bool Assembler::IsConstantPoolAt(Instruction* instr) {
+  // The constant pool marker is made of two instructions. These instructions
+  // will never be emitted by the JIT, so checking for the first one is enough:
+  // 0: ldr xzr, #<size of pool>
+  bool result = instr->IsLdrLiteralX() && (instr->Rt() == xzr.code());
+
+  // It is still worth asserting the marker is complete.
+  // 4: blr xzr
+  ASSERT(!result || (instr->following()->IsBranchAndLinkToRegister() &&
+                     instr->following()->Rn() == xzr.code()));
+
+  return result;
+}
+
+
+int Assembler::ConstantPoolSizeAt(Instruction* instr) {
+  if (IsConstantPoolAt(instr)) {
+    return instr->ImmLLiteral();
+  } else {
+    return -1;
+  }
+}
+
+
+void Assembler::ConstantPoolMarker(uint32_t size) {
+  ASSERT(is_const_pool_blocked());
+  // + 1 is for the crash guard.
+  Emit(LDR_x_lit | ImmLLiteral(2 * size + 1) | Rt(xzr));
+}
+
+
+void Assembler::ConstantPoolGuard() {
+#ifdef DEBUG
+  // Currently this is only used after a constant pool marker.
+  ASSERT(is_const_pool_blocked());
+  Instruction* instr = reinterpret_cast<Instruction*>(pc_);
+  ASSERT(instr->preceding()->IsLdrLiteralX() &&
+         instr->preceding()->Rt() == xzr.code());
+#endif
+
+  // We must generate only one instruction.
+  Emit(BLR | Rn(xzr));
+}
+
+
+void Assembler::br(const Register& xn) {
+  positions_recorder()->WriteRecordedPositions();
+  ASSERT(xn.Is64Bits());
+  Emit(BR | Rn(xn));
+}
+
+
+void Assembler::blr(const Register& xn) {
+  positions_recorder()->WriteRecordedPositions();
+  ASSERT(xn.Is64Bits());
+  // The pattern 'blr xzr' is used as a guard to detect when execution falls
+  // through the constant pool. It should not be emitted.
+  ASSERT(!xn.Is(xzr));
+  Emit(BLR | Rn(xn));
+}
+
+
+void Assembler::ret(const Register& xn) {
+  positions_recorder()->WriteRecordedPositions();
+  ASSERT(xn.Is64Bits());
+  Emit(RET | Rn(xn));
+}
+
+
+void Assembler::b(int imm26) {
+  Emit(B | ImmUncondBranch(imm26));
+}
+
+
+void Assembler::b(Label* label) {
+  positions_recorder()->WriteRecordedPositions();
+  b(LinkAndGetInstructionOffsetTo(label));
+}
+
+
+void Assembler::b(int imm19, Condition cond) {
+  Emit(B_cond | ImmCondBranch(imm19) | cond);
+}
+
+
+void Assembler::b(Label* label, Condition cond) {
+  positions_recorder()->WriteRecordedPositions();
+  b(LinkAndGetInstructionOffsetTo(label), cond);
+}
+
+
+void Assembler::bl(int imm26) {
+  positions_recorder()->WriteRecordedPositions();
+  Emit(BL | ImmUncondBranch(imm26));
+}
+
+
+void Assembler::bl(Label* label) {
+  positions_recorder()->WriteRecordedPositions();
+  bl(LinkAndGetInstructionOffsetTo(label));
+}
+
+
+void Assembler::cbz(const Register& rt,
+                    int imm19) {
+  positions_recorder()->WriteRecordedPositions();
+  Emit(SF(rt) | CBZ | ImmCmpBranch(imm19) | Rt(rt));
+}
+
+
+void Assembler::cbz(const Register& rt,
+                    Label* label) {
+  positions_recorder()->WriteRecordedPositions();
+  cbz(rt, LinkAndGetInstructionOffsetTo(label));
+}
+
+
+void Assembler::cbnz(const Register& rt,
+                     int imm19) {
+  positions_recorder()->WriteRecordedPositions();
+  Emit(SF(rt) | CBNZ | ImmCmpBranch(imm19) | Rt(rt));
+}
+
+
+void Assembler::cbnz(const Register& rt,
+                     Label* label) {
+  positions_recorder()->WriteRecordedPositions();
+  cbnz(rt, LinkAndGetInstructionOffsetTo(label));
+}
+
+
+void Assembler::tbz(const Register& rt,
+                    unsigned bit_pos,
+                    int imm14) {
+  positions_recorder()->WriteRecordedPositions();
+  ASSERT(rt.Is64Bits() || (rt.Is32Bits() && (bit_pos < kWRegSize)));
+  Emit(TBZ | ImmTestBranchBit(bit_pos) | ImmTestBranch(imm14) | Rt(rt));
+}
+
+
+void Assembler::tbz(const Register& rt,
+                    unsigned bit_pos,
+                    Label* label) {
+  positions_recorder()->WriteRecordedPositions();
+  tbz(rt, bit_pos, LinkAndGetInstructionOffsetTo(label));
+}
+
+
+void Assembler::tbnz(const Register& rt,
+                     unsigned bit_pos,
+                     int imm14) {
+  positions_recorder()->WriteRecordedPositions();
+  ASSERT(rt.Is64Bits() || (rt.Is32Bits() && (bit_pos < kWRegSize)));
+  Emit(TBNZ | ImmTestBranchBit(bit_pos) | ImmTestBranch(imm14) | Rt(rt));
+}
+
+
+void Assembler::tbnz(const Register& rt,
+                     unsigned bit_pos,
+                     Label* label) {
+  positions_recorder()->WriteRecordedPositions();
+  tbnz(rt, bit_pos, LinkAndGetInstructionOffsetTo(label));
+}
+
+
+void Assembler::adr(const Register& rd, int imm21) {
+  ASSERT(rd.Is64Bits());
+  Emit(ADR | ImmPCRelAddress(imm21) | Rd(rd));
+}
+
+
+void Assembler::adr(const Register& rd, Label* label) {
+  adr(rd, LinkAndGetByteOffsetTo(label));
+}
+
+
+void Assembler::add(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  AddSub(rd, rn, operand, LeaveFlags, ADD);
+}
+
+
+void Assembler::adds(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  AddSub(rd, rn, operand, SetFlags, ADD);
+}
+
+
+void Assembler::cmn(const Register& rn,
+                    const Operand& operand) {
+  Register zr = AppropriateZeroRegFor(rn);
+  adds(zr, rn, operand);
+}
+
+
+void Assembler::sub(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  AddSub(rd, rn, operand, LeaveFlags, SUB);
+}
+
+
+void Assembler::subs(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  AddSub(rd, rn, operand, SetFlags, SUB);
+}
+
+
+void Assembler::cmp(const Register& rn, const Operand& operand) {
+  Register zr = AppropriateZeroRegFor(rn);
+  subs(zr, rn, operand);
+}
+
+
+void Assembler::neg(const Register& rd, const Operand& operand) {
+  Register zr = AppropriateZeroRegFor(rd);
+  sub(rd, zr, operand);
+}
+
+
+void Assembler::negs(const Register& rd, const Operand& operand) {
+  Register zr = AppropriateZeroRegFor(rd);
+  subs(rd, zr, operand);
+}
+
+
+void Assembler::adc(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  AddSubWithCarry(rd, rn, operand, LeaveFlags, ADC);
+}
+
+
+void Assembler::adcs(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  AddSubWithCarry(rd, rn, operand, SetFlags, ADC);
+}
+
+
+void Assembler::sbc(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  AddSubWithCarry(rd, rn, operand, LeaveFlags, SBC);
+}
+
+
+void Assembler::sbcs(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  AddSubWithCarry(rd, rn, operand, SetFlags, SBC);
+}
+
+
+void Assembler::ngc(const Register& rd, const Operand& operand) {
+  Register zr = AppropriateZeroRegFor(rd);
+  sbc(rd, zr, operand);
+}
+
+
+void Assembler::ngcs(const Register& rd, const Operand& operand) {
+  Register zr = AppropriateZeroRegFor(rd);
+  sbcs(rd, zr, operand);
+}
+
+
+// Logical instructions.
+void Assembler::and_(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  Logical(rd, rn, operand, AND);
+}
+
+
+void Assembler::ands(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  Logical(rd, rn, operand, ANDS);
+}
+
+
+void Assembler::tst(const Register& rn,
+                    const Operand& operand) {
+  ands(AppropriateZeroRegFor(rn), rn, operand);
+}
+
+
+void Assembler::bic(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  Logical(rd, rn, operand, BIC);
+}
+
+
+void Assembler::bics(const Register& rd,
+                     const Register& rn,
+                     const Operand& operand) {
+  Logical(rd, rn, operand, BICS);
+}
+
+
+void Assembler::orr(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  Logical(rd, rn, operand, ORR);
+}
+
+
+void Assembler::orn(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  Logical(rd, rn, operand, ORN);
+}
+
+
+void Assembler::eor(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  Logical(rd, rn, operand, EOR);
+}
+
+
+void Assembler::eon(const Register& rd,
+                    const Register& rn,
+                    const Operand& operand) {
+  Logical(rd, rn, operand, EON);
+}
+
+
+void Assembler::lslv(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | LSLV | Rm(rm) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::lsrv(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | LSRV | Rm(rm) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::asrv(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | ASRV | Rm(rm) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::rorv(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | RORV | Rm(rm) | Rn(rn) | Rd(rd));
+}
+
+
+// Bitfield operations.
+void Assembler::bfm(const Register& rd,
+                     const Register& rn,
+                     unsigned immr,
+                     unsigned imms) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  Instr N = SF(rd) >> (kSFOffset - kBitfieldNOffset);
+  Emit(SF(rd) | BFM | N |
+       ImmR(immr, rd.SizeInBits()) |
+       ImmS(imms, rn.SizeInBits()) |
+       Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::sbfm(const Register& rd,
+                     const Register& rn,
+                     unsigned immr,
+                     unsigned imms) {
+  ASSERT(rd.Is64Bits() || rn.Is32Bits());
+  Instr N = SF(rd) >> (kSFOffset - kBitfieldNOffset);
+  Emit(SF(rd) | SBFM | N |
+       ImmR(immr, rd.SizeInBits()) |
+       ImmS(imms, rn.SizeInBits()) |
+       Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::ubfm(const Register& rd,
+                     const Register& rn,
+                     unsigned immr,
+                     unsigned imms) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  Instr N = SF(rd) >> (kSFOffset - kBitfieldNOffset);
+  Emit(SF(rd) | UBFM | N |
+       ImmR(immr, rd.SizeInBits()) |
+       ImmS(imms, rn.SizeInBits()) |
+       Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::extr(const Register& rd,
+                     const Register& rn,
+                     const Register& rm,
+                     unsigned lsb) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Instr N = SF(rd) >> (kSFOffset - kBitfieldNOffset);
+  Emit(SF(rd) | EXTR | N | Rm(rm) |
+       ImmS(lsb, rn.SizeInBits()) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::csel(const Register& rd,
+                     const Register& rn,
+                     const Register& rm,
+                     Condition cond) {
+  ConditionalSelect(rd, rn, rm, cond, CSEL);
+}
+
+
+void Assembler::csinc(const Register& rd,
+                      const Register& rn,
+                      const Register& rm,
+                      Condition cond) {
+  ConditionalSelect(rd, rn, rm, cond, CSINC);
+}
+
+
+void Assembler::csinv(const Register& rd,
+                      const Register& rn,
+                      const Register& rm,
+                      Condition cond) {
+  ConditionalSelect(rd, rn, rm, cond, CSINV);
+}
+
+
+void Assembler::csneg(const Register& rd,
+                      const Register& rn,
+                      const Register& rm,
+                      Condition cond) {
+  ConditionalSelect(rd, rn, rm, cond, CSNEG);
+}
+
+
+void Assembler::cset(const Register &rd, Condition cond) {
+  ASSERT((cond != al) && (cond != nv));
+  Register zr = AppropriateZeroRegFor(rd);
+  csinc(rd, zr, zr, InvertCondition(cond));
+}
+
+
+void Assembler::csetm(const Register &rd, Condition cond) {
+  ASSERT((cond != al) && (cond != nv));
+  Register zr = AppropriateZeroRegFor(rd);
+  csinv(rd, zr, zr, InvertCondition(cond));
+}
+
+
+void Assembler::cinc(const Register &rd, const Register &rn, Condition cond) {
+  ASSERT((cond != al) && (cond != nv));
+  csinc(rd, rn, rn, InvertCondition(cond));
+}
+
+
+void Assembler::cinv(const Register &rd, const Register &rn, Condition cond) {
+  ASSERT((cond != al) && (cond != nv));
+  csinv(rd, rn, rn, InvertCondition(cond));
+}
+
+
+void Assembler::cneg(const Register &rd, const Register &rn, Condition cond) {
+  ASSERT((cond != al) && (cond != nv));
+  csneg(rd, rn, rn, InvertCondition(cond));
+}
+
+
+void Assembler::ConditionalSelect(const Register& rd,
+                                  const Register& rn,
+                                  const Register& rm,
+                                  Condition cond,
+                                  ConditionalSelectOp op) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | op | Rm(rm) | Cond(cond) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::ccmn(const Register& rn,
+                     const Operand& operand,
+                     StatusFlags nzcv,
+                     Condition cond) {
+  ConditionalCompare(rn, operand, nzcv, cond, CCMN);
+}
+
+
+void Assembler::ccmp(const Register& rn,
+                     const Operand& operand,
+                     StatusFlags nzcv,
+                     Condition cond) {
+  ConditionalCompare(rn, operand, nzcv, cond, CCMP);
+}
+
+
+void Assembler::DataProcessing3Source(const Register& rd,
+                                      const Register& rn,
+                                      const Register& rm,
+                                      const Register& ra,
+                                      DataProcessing3SourceOp op) {
+  Emit(SF(rd) | op | Rm(rm) | Ra(ra) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::mul(const Register& rd,
+                    const Register& rn,
+                    const Register& rm) {
+  ASSERT(AreSameSizeAndType(rd, rn, rm));
+  Register zr = AppropriateZeroRegFor(rn);
+  DataProcessing3Source(rd, rn, rm, zr, MADD);
+}
+
+
+void Assembler::madd(const Register& rd,
+                     const Register& rn,
+                     const Register& rm,
+                     const Register& ra) {
+  ASSERT(AreSameSizeAndType(rd, rn, rm, ra));
+  DataProcessing3Source(rd, rn, rm, ra, MADD);
+}
+
+
+void Assembler::mneg(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(AreSameSizeAndType(rd, rn, rm));
+  Register zr = AppropriateZeroRegFor(rn);
+  DataProcessing3Source(rd, rn, rm, zr, MSUB);
+}
+
+
+void Assembler::msub(const Register& rd,
+                     const Register& rn,
+                     const Register& rm,
+                     const Register& ra) {
+  ASSERT(AreSameSizeAndType(rd, rn, rm, ra));
+  DataProcessing3Source(rd, rn, rm, ra, MSUB);
+}
+
+
+void Assembler::smaddl(const Register& rd,
+                       const Register& rn,
+                       const Register& rm,
+                       const Register& ra) {
+  ASSERT(rd.Is64Bits() && ra.Is64Bits());
+  ASSERT(rn.Is32Bits() && rm.Is32Bits());
+  DataProcessing3Source(rd, rn, rm, ra, SMADDL_x);
+}
+
+
+void Assembler::smsubl(const Register& rd,
+                       const Register& rn,
+                       const Register& rm,
+                       const Register& ra) {
+  ASSERT(rd.Is64Bits() && ra.Is64Bits());
+  ASSERT(rn.Is32Bits() && rm.Is32Bits());
+  DataProcessing3Source(rd, rn, rm, ra, SMSUBL_x);
+}
+
+
+void Assembler::umaddl(const Register& rd,
+                       const Register& rn,
+                       const Register& rm,
+                       const Register& ra) {
+  ASSERT(rd.Is64Bits() && ra.Is64Bits());
+  ASSERT(rn.Is32Bits() && rm.Is32Bits());
+  DataProcessing3Source(rd, rn, rm, ra, UMADDL_x);
+}
+
+
+void Assembler::umsubl(const Register& rd,
+                       const Register& rn,
+                       const Register& rm,
+                       const Register& ra) {
+  ASSERT(rd.Is64Bits() && ra.Is64Bits());
+  ASSERT(rn.Is32Bits() && rm.Is32Bits());
+  DataProcessing3Source(rd, rn, rm, ra, UMSUBL_x);
+}
+
+
+void Assembler::smull(const Register& rd,
+                      const Register& rn,
+                      const Register& rm) {
+  ASSERT(rd.Is64Bits());
+  ASSERT(rn.Is32Bits() && rm.Is32Bits());
+  DataProcessing3Source(rd, rn, rm, xzr, SMADDL_x);
+}
+
+
+void Assembler::smulh(const Register& rd,
+                      const Register& rn,
+                      const Register& rm) {
+  ASSERT(AreSameSizeAndType(rd, rn, rm));
+  DataProcessing3Source(rd, rn, rm, xzr, SMULH_x);
+}
+
+
+void Assembler::sdiv(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | SDIV | Rm(rm) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::udiv(const Register& rd,
+                     const Register& rn,
+                     const Register& rm) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == rm.SizeInBits());
+  Emit(SF(rd) | UDIV | Rm(rm) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::rbit(const Register& rd,
+                     const Register& rn) {
+  DataProcessing1Source(rd, rn, RBIT);
+}
+
+
+void Assembler::rev16(const Register& rd,
+                      const Register& rn) {
+  DataProcessing1Source(rd, rn, REV16);
+}
+
+
+void Assembler::rev32(const Register& rd,
+                      const Register& rn) {
+  ASSERT(rd.Is64Bits());
+  DataProcessing1Source(rd, rn, REV);
+}
+
+
+void Assembler::rev(const Register& rd,
+                    const Register& rn) {
+  DataProcessing1Source(rd, rn, rd.Is64Bits() ? REV_x : REV_w);
+}
+
+
+void Assembler::clz(const Register& rd,
+                    const Register& rn) {
+  DataProcessing1Source(rd, rn, CLZ);
+}
+
+
+void Assembler::cls(const Register& rd,
+                    const Register& rn) {
+  DataProcessing1Source(rd, rn, CLS);
+}
+
+
+void Assembler::ldp(const CPURegister& rt,
+                    const CPURegister& rt2,
+                    const MemOperand& src) {
+  LoadStorePair(rt, rt2, src, LoadPairOpFor(rt, rt2));
+}
+
+
+void Assembler::stp(const CPURegister& rt,
+                    const CPURegister& rt2,
+                    const MemOperand& dst) {
+  LoadStorePair(rt, rt2, dst, StorePairOpFor(rt, rt2));
+}
+
+
+void Assembler::ldpsw(const Register& rt,
+                      const Register& rt2,
+                      const MemOperand& src) {
+  ASSERT(rt.Is64Bits());
+  LoadStorePair(rt, rt2, src, LDPSW_x);
+}
+
+
+void Assembler::LoadStorePair(const CPURegister& rt,
+                              const CPURegister& rt2,
+                              const MemOperand& addr,
+                              LoadStorePairOp op) {
+  // 'rt' and 'rt2' can only be aliased for stores.
+  ASSERT(((op & LoadStorePairLBit) == 0) || !rt.Is(rt2));
+  ASSERT(AreSameSizeAndType(rt, rt2));
+
+  Instr memop = op | Rt(rt) | Rt2(rt2) | RnSP(addr.base()) |
+                ImmLSPair(addr.offset(), CalcLSPairDataSize(op));
+
+  Instr addrmodeop;
+  if (addr.IsImmediateOffset()) {
+    addrmodeop = LoadStorePairOffsetFixed;
+  } else {
+    // Pre-index and post-index modes.
+    ASSERT(!rt.Is(addr.base()));
+    ASSERT(!rt2.Is(addr.base()));
+    ASSERT(addr.offset() != 0);
+    if (addr.IsPreIndex()) {
+      addrmodeop = LoadStorePairPreIndexFixed;
+    } else {
+      ASSERT(addr.IsPostIndex());
+      addrmodeop = LoadStorePairPostIndexFixed;
+    }
+  }
+  Emit(addrmodeop | memop);
+}
+
+
+void Assembler::ldnp(const CPURegister& rt,
+                     const CPURegister& rt2,
+                     const MemOperand& src) {
+  LoadStorePairNonTemporal(rt, rt2, src,
+                           LoadPairNonTemporalOpFor(rt, rt2));
+}
+
+
+void Assembler::stnp(const CPURegister& rt,
+                     const CPURegister& rt2,
+                     const MemOperand& dst) {
+  LoadStorePairNonTemporal(rt, rt2, dst,
+                           StorePairNonTemporalOpFor(rt, rt2));
+}
+
+
+void Assembler::LoadStorePairNonTemporal(const CPURegister& rt,
+                                         const CPURegister& rt2,
+                                         const MemOperand& addr,
+                                         LoadStorePairNonTemporalOp op) {
+  ASSERT(!rt.Is(rt2));
+  ASSERT(AreSameSizeAndType(rt, rt2));
+  ASSERT(addr.IsImmediateOffset());
+
+  LSDataSize size = CalcLSPairDataSize(
+    static_cast<LoadStorePairOp>(op & LoadStorePairMask));
+  Emit(op | Rt(rt) | Rt2(rt2) | RnSP(addr.base()) |
+       ImmLSPair(addr.offset(), size));
+}
+
+
+// Memory instructions.
+void Assembler::ldrb(const Register& rt, const MemOperand& src) {
+  LoadStore(rt, src, LDRB_w);
+}
+
+
+void Assembler::strb(const Register& rt, const MemOperand& dst) {
+  LoadStore(rt, dst, STRB_w);
+}
+
+
+void Assembler::ldrsb(const Register& rt, const MemOperand& src) {
+  LoadStore(rt, src, rt.Is64Bits() ? LDRSB_x : LDRSB_w);
+}
+
+
+void Assembler::ldrh(const Register& rt, const MemOperand& src) {
+  LoadStore(rt, src, LDRH_w);
+}
+
+
+void Assembler::strh(const Register& rt, const MemOperand& dst) {
+  LoadStore(rt, dst, STRH_w);
+}
+
+
+void Assembler::ldrsh(const Register& rt, const MemOperand& src) {
+  LoadStore(rt, src, rt.Is64Bits() ? LDRSH_x : LDRSH_w);
+}
+
+
+void Assembler::ldr(const CPURegister& rt, const MemOperand& src) {
+  LoadStore(rt, src, LoadOpFor(rt));
+}
+
+
+void Assembler::str(const CPURegister& rt, const MemOperand& src) {
+  LoadStore(rt, src, StoreOpFor(rt));
+}
+
+
+void Assembler::ldrsw(const Register& rt, const MemOperand& src) {
+  ASSERT(rt.Is64Bits());
+  LoadStore(rt, src, LDRSW_x);
+}
+
+
+void Assembler::ldr(const Register& rt, uint64_t imm) {
+  // TODO(all): Constant pool may be garbage collected. Hence we cannot store
+  // TODO(all): arbitrary values in them. Manually move it for now.
+  // TODO(all): Fix MacroAssembler::Fmov when this is implemented.
+  UNIMPLEMENTED();
+}
+
+
+void Assembler::ldr(const FPRegister& ft, double imm) {
+  // TODO(all): Constant pool may be garbage collected. Hence we cannot store
+  // TODO(all): arbitrary values in them. Manually move it for now.
+  // TODO(all): Fix MacroAssembler::Fmov when this is implemented.
+  UNIMPLEMENTED();
+}
+
+
+void Assembler::mov(const Register& rd, const Register& rm) {
+  // Moves involving the stack pointer are encoded as add immediate with
+  // second operand of zero. Otherwise, orr with first operand zr is
+  // used.
+  if (rd.IsSP() || rm.IsSP()) {
+    add(rd, rm, 0);
+  } else {
+    orr(rd, AppropriateZeroRegFor(rd), rm);
+  }
+}
+
+
+void Assembler::mvn(const Register& rd, const Operand& operand) {
+  orn(rd, AppropriateZeroRegFor(rd), operand);
+}
+
+
+void Assembler::mrs(const Register& rt, SystemRegister sysreg) {
+  ASSERT(rt.Is64Bits());
+  Emit(MRS | ImmSystemRegister(sysreg) | Rt(rt));
+}
+
+
+void Assembler::msr(SystemRegister sysreg, const Register& rt) {
+  ASSERT(rt.Is64Bits());
+  Emit(MSR | Rt(rt) | ImmSystemRegister(sysreg));
+}
+
+
+void Assembler::hint(SystemHint code) {
+  Emit(HINT | ImmHint(code) | Rt(xzr));
+}
+
+
+void Assembler::dmb(BarrierDomain domain, BarrierType type) {
+  Emit(DMB | ImmBarrierDomain(domain) | ImmBarrierType(type));
+}
+
+
+void Assembler::dsb(BarrierDomain domain, BarrierType type) {
+  Emit(DSB | ImmBarrierDomain(domain) | ImmBarrierType(type));
+}
+
+
+void Assembler::isb() {
+  Emit(ISB | ImmBarrierDomain(FullSystem) | ImmBarrierType(BarrierAll));
+}
+
+
+void Assembler::fmov(FPRegister fd, double imm) {
+  if (fd.Is64Bits() && IsImmFP64(imm)) {
+    Emit(FMOV_d_imm | Rd(fd) | ImmFP64(imm));
+  } else if (fd.Is32Bits() && IsImmFP32(imm)) {
+    Emit(FMOV_s_imm | Rd(fd) | ImmFP32(static_cast<float>(imm)));
+  } else if ((imm == 0.0) && (copysign(1.0, imm) == 1.0)) {
+    Register zr = AppropriateZeroRegFor(fd);
+    fmov(fd, zr);
+  } else {
+    ldr(fd, imm);
+  }
+}
+
+
+void Assembler::fmov(Register rd, FPRegister fn) {
+  ASSERT(rd.SizeInBits() == fn.SizeInBits());
+  FPIntegerConvertOp op = rd.Is32Bits() ? FMOV_ws : FMOV_xd;
+  Emit(op | Rd(rd) | Rn(fn));
+}
+
+
+void Assembler::fmov(FPRegister fd, Register rn) {
+  ASSERT(fd.SizeInBits() == rn.SizeInBits());
+  FPIntegerConvertOp op = fd.Is32Bits() ? FMOV_sw : FMOV_dx;
+  Emit(op | Rd(fd) | Rn(rn));
+}
+
+
+void Assembler::fmov(FPRegister fd, FPRegister fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  Emit(FPType(fd) | FMOV | Rd(fd) | Rn(fn));
+}
+
+
+void Assembler::fadd(const FPRegister& fd,
+                     const FPRegister& fn,
+                     const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FADD);
+}
+
+
+void Assembler::fsub(const FPRegister& fd,
+                     const FPRegister& fn,
+                     const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FSUB);
+}
+
+
+void Assembler::fmul(const FPRegister& fd,
+                     const FPRegister& fn,
+                     const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FMUL);
+}
+
+
+void Assembler::fmadd(const FPRegister& fd,
+                      const FPRegister& fn,
+                      const FPRegister& fm,
+                      const FPRegister& fa) {
+  FPDataProcessing3Source(fd, fn, fm, fa, fd.Is32Bits() ? FMADD_s : FMADD_d);
+}
+
+
+void Assembler::fmsub(const FPRegister& fd,
+                      const FPRegister& fn,
+                      const FPRegister& fm,
+                      const FPRegister& fa) {
+  FPDataProcessing3Source(fd, fn, fm, fa, fd.Is32Bits() ? FMSUB_s : FMSUB_d);
+}
+
+
+void Assembler::fnmadd(const FPRegister& fd,
+                       const FPRegister& fn,
+                       const FPRegister& fm,
+                       const FPRegister& fa) {
+  FPDataProcessing3Source(fd, fn, fm, fa, fd.Is32Bits() ? FNMADD_s : FNMADD_d);
+}
+
+
+void Assembler::fnmsub(const FPRegister& fd,
+                       const FPRegister& fn,
+                       const FPRegister& fm,
+                       const FPRegister& fa) {
+  FPDataProcessing3Source(fd, fn, fm, fa, fd.Is32Bits() ? FNMSUB_s : FNMSUB_d);
+}
+
+
+void Assembler::fdiv(const FPRegister& fd,
+                     const FPRegister& fn,
+                     const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FDIV);
+}
+
+
+void Assembler::fmax(const FPRegister& fd,
+                     const FPRegister& fn,
+                     const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FMAX);
+}
+
+
+void Assembler::fmaxnm(const FPRegister& fd,
+                       const FPRegister& fn,
+                       const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FMAXNM);
+}
+
+
+void Assembler::fmin(const FPRegister& fd,
+                     const FPRegister& fn,
+                     const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FMIN);
+}
+
+
+void Assembler::fminnm(const FPRegister& fd,
+                       const FPRegister& fn,
+                       const FPRegister& fm) {
+  FPDataProcessing2Source(fd, fn, fm, FMINNM);
+}
+
+
+void Assembler::fabs(const FPRegister& fd,
+                     const FPRegister& fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  FPDataProcessing1Source(fd, fn, FABS);
+}
+
+
+void Assembler::fneg(const FPRegister& fd,
+                     const FPRegister& fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  FPDataProcessing1Source(fd, fn, FNEG);
+}
+
+
+void Assembler::fsqrt(const FPRegister& fd,
+                      const FPRegister& fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  FPDataProcessing1Source(fd, fn, FSQRT);
+}
+
+
+void Assembler::frinta(const FPRegister& fd,
+                       const FPRegister& fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  FPDataProcessing1Source(fd, fn, FRINTA);
+}
+
+
+void Assembler::frintn(const FPRegister& fd,
+                       const FPRegister& fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  FPDataProcessing1Source(fd, fn, FRINTN);
+}
+
+
+void Assembler::frintz(const FPRegister& fd,
+                       const FPRegister& fn) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  FPDataProcessing1Source(fd, fn, FRINTZ);
+}
+
+
+void Assembler::fcmp(const FPRegister& fn,
+                     const FPRegister& fm) {
+  ASSERT(fn.SizeInBits() == fm.SizeInBits());
+  Emit(FPType(fn) | FCMP | Rm(fm) | Rn(fn));
+}
+
+
+void Assembler::fcmp(const FPRegister& fn,
+                     double value) {
+  USE(value);
+  // Although the fcmp instruction can strictly only take an immediate value of
+  // +0.0, we don't need to check for -0.0 because the sign of 0.0 doesn't
+  // affect the result of the comparison.
+  ASSERT(value == 0.0);
+  Emit(FPType(fn) | FCMP_zero | Rn(fn));
+}
+
+
+void Assembler::fccmp(const FPRegister& fn,
+                      const FPRegister& fm,
+                      StatusFlags nzcv,
+                      Condition cond) {
+  ASSERT(fn.SizeInBits() == fm.SizeInBits());
+  Emit(FPType(fn) | FCCMP | Rm(fm) | Cond(cond) | Rn(fn) | Nzcv(nzcv));
+}
+
+
+void Assembler::fcsel(const FPRegister& fd,
+                      const FPRegister& fn,
+                      const FPRegister& fm,
+                      Condition cond) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  ASSERT(fd.SizeInBits() == fm.SizeInBits());
+  Emit(FPType(fd) | FCSEL | Rm(fm) | Cond(cond) | Rn(fn) | Rd(fd));
+}
+
+
+void Assembler::FPConvertToInt(const Register& rd,
+                               const FPRegister& fn,
+                               FPIntegerConvertOp op) {
+  Emit(SF(rd) | FPType(fn) | op | Rn(fn) | Rd(rd));
+}
+
+
+void Assembler::fcvt(const FPRegister& fd,
+                     const FPRegister& fn) {
+  if (fd.Is64Bits()) {
+    // Convert float to double.
+    ASSERT(fn.Is32Bits());
+    FPDataProcessing1Source(fd, fn, FCVT_ds);
+  } else {
+    // Convert double to float.
+    ASSERT(fn.Is64Bits());
+    FPDataProcessing1Source(fd, fn, FCVT_sd);
+  }
+}
+
+
+void Assembler::fcvtau(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTAU);
+}
+
+
+void Assembler::fcvtas(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTAS);
+}
+
+
+void Assembler::fcvtmu(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTMU);
+}
+
+
+void Assembler::fcvtms(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTMS);
+}
+
+
+void Assembler::fcvtnu(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTNU);
+}
+
+
+void Assembler::fcvtns(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTNS);
+}
+
+
+void Assembler::fcvtzu(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTZU);
+}
+
+
+void Assembler::fcvtzs(const Register& rd, const FPRegister& fn) {
+  FPConvertToInt(rd, fn, FCVTZS);
+}
+
+
+void Assembler::scvtf(const FPRegister& fd,
+                      const Register& rn,
+                      unsigned fbits) {
+  if (fbits == 0) {
+    Emit(SF(rn) | FPType(fd) | SCVTF | Rn(rn) | Rd(fd));
+  } else {
+    Emit(SF(rn) | FPType(fd) | SCVTF_fixed | FPScale(64 - fbits) | Rn(rn) |
+         Rd(fd));
+  }
+}
+
+
+void Assembler::ucvtf(const FPRegister& fd,
+                      const Register& rn,
+                      unsigned fbits) {
+  if (fbits == 0) {
+    Emit(SF(rn) | FPType(fd) | UCVTF | Rn(rn) | Rd(fd));
+  } else {
+    Emit(SF(rn) | FPType(fd) | UCVTF_fixed | FPScale(64 - fbits) | Rn(rn) |
+         Rd(fd));
+  }
+}
+
+
+// Note:
+// Below, a difference in case for the same letter indicates a
+// negated bit.
+// If b is 1, then B is 0.
+Instr Assembler::ImmFP32(float imm) {
+  ASSERT(IsImmFP32(imm));
+  // bits: aBbb.bbbc.defg.h000.0000.0000.0000.0000
+  uint32_t bits = float_to_rawbits(imm);
+  // bit7: a000.0000
+  uint32_t bit7 = ((bits >> 31) & 0x1) << 7;
+  // bit6: 0b00.0000
+  uint32_t bit6 = ((bits >> 29) & 0x1) << 6;
+  // bit5_to_0: 00cd.efgh
+  uint32_t bit5_to_0 = (bits >> 19) & 0x3f;
+
+  return (bit7 | bit6 | bit5_to_0) << ImmFP_offset;
+}
+
+
+Instr Assembler::ImmFP64(double imm) {
+  ASSERT(IsImmFP64(imm));
+  // bits: aBbb.bbbb.bbcd.efgh.0000.0000.0000.0000
+  //       0000.0000.0000.0000.0000.0000.0000.0000
+  uint64_t bits = double_to_rawbits(imm);
+  // bit7: a000.0000
+  uint32_t bit7 = ((bits >> 63) & 0x1) << 7;
+  // bit6: 0b00.0000
+  uint32_t bit6 = ((bits >> 61) & 0x1) << 6;
+  // bit5_to_0: 00cd.efgh
+  uint32_t bit5_to_0 = (bits >> 48) & 0x3f;
+
+  return (bit7 | bit6 | bit5_to_0) << ImmFP_offset;
+}
+
+
+// Code generation helpers.
+void Assembler::MoveWide(const Register& rd,
+                         uint64_t imm,
+                         int shift,
+                         MoveWideImmediateOp mov_op) {
+  if (shift >= 0) {
+    // Explicit shift specified.
+    ASSERT((shift == 0) || (shift == 16) || (shift == 32) || (shift == 48));
+    ASSERT(rd.Is64Bits() || (shift == 0) || (shift == 16));
+    shift /= 16;
+  } else {
+    // Calculate a new immediate and shift combination to encode the immediate
+    // argument.
+    shift = 0;
+    if ((imm & ~0xffffUL) == 0) {
+      // Nothing to do.
+    } else if ((imm & ~(0xffffUL << 16)) == 0) {
+      imm >>= 16;
+      shift = 1;
+    } else if ((imm & ~(0xffffUL << 32)) == 0) {
+      ASSERT(rd.Is64Bits());
+      imm >>= 32;
+      shift = 2;
+    } else if ((imm & ~(0xffffUL << 48)) == 0) {
+      ASSERT(rd.Is64Bits());
+      imm >>= 48;
+      shift = 3;
+    }
+  }
+
+  ASSERT(is_uint16(imm));
+
+  Emit(SF(rd) | MoveWideImmediateFixed | mov_op |
+       Rd(rd) | ImmMoveWide(imm) | ShiftMoveWide(shift));
+}
+
+
+void Assembler::AddSub(const Register& rd,
+                       const Register& rn,
+                       const Operand& operand,
+                       FlagsUpdate S,
+                       AddSubOp op) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(!operand.NeedsRelocation());
+  if (operand.IsImmediate()) {
+    int64_t immediate = operand.immediate();
+    ASSERT(IsImmAddSub(immediate));
+    Instr dest_reg = (S == SetFlags) ? Rd(rd) : RdSP(rd);
+    Emit(SF(rd) | AddSubImmediateFixed | op | Flags(S) |
+         ImmAddSub(immediate) | dest_reg | RnSP(rn));
+  } else if (operand.IsShiftedRegister()) {
+    ASSERT(operand.reg().SizeInBits() == rd.SizeInBits());
+    ASSERT(operand.shift() != ROR);
+
+    // For instructions of the form:
+    //   add/sub   wsp, <Wn>, <Wm> [, LSL #0-3 ]
+    //   add/sub   <Wd>, wsp, <Wm> [, LSL #0-3 ]
+    //   add/sub   wsp, wsp, <Wm> [, LSL #0-3 ]
+    //   adds/subs <Wd>, wsp, <Wm> [, LSL #0-3 ]
+    // or their 64-bit register equivalents, convert the operand from shifted to
+    // extended register mode, and emit an add/sub extended instruction.
+    if (rn.IsSP() || rd.IsSP()) {
+      ASSERT(!(rd.IsSP() && (S == SetFlags)));
+      DataProcExtendedRegister(rd, rn, operand.ToExtendedRegister(), S,
+                               AddSubExtendedFixed | op);
+    } else {
+      DataProcShiftedRegister(rd, rn, operand, S, AddSubShiftedFixed | op);
+    }
+  } else {
+    ASSERT(operand.IsExtendedRegister());
+    DataProcExtendedRegister(rd, rn, operand, S, AddSubExtendedFixed | op);
+  }
+}
+
+
+void Assembler::AddSubWithCarry(const Register& rd,
+                                const Register& rn,
+                                const Operand& operand,
+                                FlagsUpdate S,
+                                AddSubWithCarryOp op) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(rd.SizeInBits() == operand.reg().SizeInBits());
+  ASSERT(operand.IsShiftedRegister() && (operand.shift_amount() == 0));
+  ASSERT(!operand.NeedsRelocation());
+  Emit(SF(rd) | op | Flags(S) | Rm(operand.reg()) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::hlt(int code) {
+  ASSERT(is_uint16(code));
+  Emit(HLT | ImmException(code));
+}
+
+
+void Assembler::brk(int code) {
+  ASSERT(is_uint16(code));
+  Emit(BRK | ImmException(code));
+}
+
+
+void Assembler::debug(const char* message, uint32_t code, Instr params) {
+#ifdef USE_SIMULATOR
+  // Don't generate simulator specific code if we are building a snapshot, which
+  // might be run on real hardware.
+  if (!Serializer::enabled()) {
+#ifdef DEBUG
+    Serializer::TooLateToEnableNow();
+#endif
+    // The arguments to the debug marker need to be contiguous in memory, so
+    // make sure we don't try to emit a literal pool.
+    BlockConstPoolScope scope(this);
+
+    Label start;
+    bind(&start);
+
+    // Refer to instructions-a64.h for a description of the marker and its
+    // arguments.
+    hlt(kImmExceptionIsDebug);
+    ASSERT(SizeOfCodeGeneratedSince(&start) == kDebugCodeOffset);
+    dc32(code);
+    ASSERT(SizeOfCodeGeneratedSince(&start) == kDebugParamsOffset);
+    dc32(params);
+    ASSERT(SizeOfCodeGeneratedSince(&start) == kDebugMessageOffset);
+    EmitStringData(message);
+    hlt(kImmExceptionIsUnreachable);
+
+    return;
+  }
+  // Fall through if Serializer is enabled.
+#endif
+
+  if (params & BREAK) {
+    hlt(kImmExceptionIsDebug);
+  }
+}
+
+
+void Assembler::Logical(const Register& rd,
+                        const Register& rn,
+                        const Operand& operand,
+                        LogicalOp op) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  ASSERT(!operand.NeedsRelocation());
+  if (operand.IsImmediate()) {
+    int64_t immediate = operand.immediate();
+    unsigned reg_size = rd.SizeInBits();
+
+    ASSERT(immediate != 0);
+    ASSERT(immediate != -1);
+    ASSERT(rd.Is64Bits() || is_uint32(immediate));
+
+    // If the operation is NOT, invert the operation and immediate.
+    if ((op & NOT) == NOT) {
+      op = static_cast<LogicalOp>(op & ~NOT);
+      immediate = rd.Is64Bits() ? ~immediate : (~immediate & kWRegMask);
+    }
+
+    unsigned n, imm_s, imm_r;
+    if (IsImmLogical(immediate, reg_size, &n, &imm_s, &imm_r)) {
+      // Immediate can be encoded in the instruction.
+      LogicalImmediate(rd, rn, n, imm_s, imm_r, op);
+    } else {
+      // This case is handled in the macro assembler.
+      UNREACHABLE();
+    }
+  } else {
+    ASSERT(operand.IsShiftedRegister());
+    ASSERT(operand.reg().SizeInBits() == rd.SizeInBits());
+    Instr dp_op = static_cast<Instr>(op | LogicalShiftedFixed);
+    DataProcShiftedRegister(rd, rn, operand, LeaveFlags, dp_op);
+  }
+}
+
+
+void Assembler::LogicalImmediate(const Register& rd,
+                                 const Register& rn,
+                                 unsigned n,
+                                 unsigned imm_s,
+                                 unsigned imm_r,
+                                 LogicalOp op) {
+  unsigned reg_size = rd.SizeInBits();
+  Instr dest_reg = (op == ANDS) ? Rd(rd) : RdSP(rd);
+  Emit(SF(rd) | LogicalImmediateFixed | op | BitN(n, reg_size) |
+       ImmSetBits(imm_s, reg_size) | ImmRotate(imm_r, reg_size) | dest_reg |
+       Rn(rn));
+}
+
+
+void Assembler::ConditionalCompare(const Register& rn,
+                                   const Operand& operand,
+                                   StatusFlags nzcv,
+                                   Condition cond,
+                                   ConditionalCompareOp op) {
+  Instr ccmpop;
+  ASSERT(!operand.NeedsRelocation());
+  if (operand.IsImmediate()) {
+    int64_t immediate = operand.immediate();
+    ASSERT(IsImmConditionalCompare(immediate));
+    ccmpop = ConditionalCompareImmediateFixed | op | ImmCondCmp(immediate);
+  } else {
+    ASSERT(operand.IsShiftedRegister() && (operand.shift_amount() == 0));
+    ccmpop = ConditionalCompareRegisterFixed | op | Rm(operand.reg());
+  }
+  Emit(SF(rn) | ccmpop | Cond(cond) | Rn(rn) | Nzcv(nzcv));
+}
+
+
+void Assembler::DataProcessing1Source(const Register& rd,
+                                      const Register& rn,
+                                      DataProcessing1SourceOp op) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+  Emit(SF(rn) | op | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::FPDataProcessing1Source(const FPRegister& fd,
+                                        const FPRegister& fn,
+                                        FPDataProcessing1SourceOp op) {
+  Emit(FPType(fn) | op | Rn(fn) | Rd(fd));
+}
+
+
+void Assembler::FPDataProcessing2Source(const FPRegister& fd,
+                                        const FPRegister& fn,
+                                        const FPRegister& fm,
+                                        FPDataProcessing2SourceOp op) {
+  ASSERT(fd.SizeInBits() == fn.SizeInBits());
+  ASSERT(fd.SizeInBits() == fm.SizeInBits());
+  Emit(FPType(fd) | op | Rm(fm) | Rn(fn) | Rd(fd));
+}
+
+
+void Assembler::FPDataProcessing3Source(const FPRegister& fd,
+                                        const FPRegister& fn,
+                                        const FPRegister& fm,
+                                        const FPRegister& fa,
+                                        FPDataProcessing3SourceOp op) {
+  ASSERT(AreSameSizeAndType(fd, fn, fm, fa));
+  Emit(FPType(fd) | op | Rm(fm) | Rn(fn) | Rd(fd) | Ra(fa));
+}
+
+
+void Assembler::EmitShift(const Register& rd,
+                          const Register& rn,
+                          Shift shift,
+                          unsigned shift_amount) {
+  switch (shift) {
+    case LSL:
+      lsl(rd, rn, shift_amount);
+      break;
+    case LSR:
+      lsr(rd, rn, shift_amount);
+      break;
+    case ASR:
+      asr(rd, rn, shift_amount);
+      break;
+    case ROR:
+      ror(rd, rn, shift_amount);
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void Assembler::EmitExtendShift(const Register& rd,
+                                const Register& rn,
+                                Extend extend,
+                                unsigned left_shift) {
+  ASSERT(rd.SizeInBits() >= rn.SizeInBits());
+  unsigned reg_size = rd.SizeInBits();
+  // Use the correct size of register.
+  Register rn_ = Register::Create(rn.code(), rd.SizeInBits());
+  // Bits extracted are high_bit:0.
+  unsigned high_bit = (8 << (extend & 0x3)) - 1;
+  // Number of bits left in the result that are not introduced by the shift.
+  unsigned non_shift_bits = (reg_size - left_shift) & (reg_size - 1);
+
+  if ((non_shift_bits > high_bit) || (non_shift_bits == 0)) {
+    switch (extend) {
+      case UXTB:
+      case UXTH:
+      case UXTW: ubfm(rd, rn_, non_shift_bits, high_bit); break;
+      case SXTB:
+      case SXTH:
+      case SXTW: sbfm(rd, rn_, non_shift_bits, high_bit); break;
+      case UXTX:
+      case SXTX: {
+        ASSERT(rn.SizeInBits() == kXRegSize);
+        // Nothing to extend. Just shift.
+        lsl(rd, rn_, left_shift);
+        break;
+      }
+      default: UNREACHABLE();
+    }
+  } else {
+    // No need to extend as the extended bits would be shifted away.
+    lsl(rd, rn_, left_shift);
+  }
+}
+
+
+void Assembler::DataProcShiftedRegister(const Register& rd,
+                                        const Register& rn,
+                                        const Operand& operand,
+                                        FlagsUpdate S,
+                                        Instr op) {
+  ASSERT(operand.IsShiftedRegister());
+  ASSERT(rn.Is64Bits() || (rn.Is32Bits() && is_uint5(operand.shift_amount())));
+  ASSERT(!operand.NeedsRelocation());
+  Emit(SF(rd) | op | Flags(S) |
+       ShiftDP(operand.shift()) | ImmDPShift(operand.shift_amount()) |
+       Rm(operand.reg()) | Rn(rn) | Rd(rd));
+}
+
+
+void Assembler::DataProcExtendedRegister(const Register& rd,
+                                         const Register& rn,
+                                         const Operand& operand,
+                                         FlagsUpdate S,
+                                         Instr op) {
+  ASSERT(!operand.NeedsRelocation());
+  Instr dest_reg = (S == SetFlags) ? Rd(rd) : RdSP(rd);
+  Emit(SF(rd) | op | Flags(S) | Rm(operand.reg()) |
+       ExtendMode(operand.extend()) | ImmExtendShift(operand.shift_amount()) |
+       dest_reg | RnSP(rn));
+}
+
+
+bool Assembler::IsImmAddSub(int64_t immediate) {
+  return is_uint12(immediate) ||
+         (is_uint12(immediate >> 12) && ((immediate & 0xfff) == 0));
+}
+
+void Assembler::LoadStore(const CPURegister& rt,
+                          const MemOperand& addr,
+                          LoadStoreOp op) {
+  Instr memop = op | Rt(rt) | RnSP(addr.base());
+  ptrdiff_t offset = addr.offset();
+
+  if (addr.IsImmediateOffset()) {
+    LSDataSize size = CalcLSDataSize(op);
+    if (IsImmLSScaled(offset, size)) {
+      // Use the scaled addressing mode.
+      Emit(LoadStoreUnsignedOffsetFixed | memop |
+           ImmLSUnsigned(offset >> size));
+    } else if (IsImmLSUnscaled(offset)) {
+      // Use the unscaled addressing mode.
+      Emit(LoadStoreUnscaledOffsetFixed | memop | ImmLS(offset));
+    } else {
+      // This case is handled in the macro assembler.
+      UNREACHABLE();
+    }
+  } else if (addr.IsRegisterOffset()) {
+    Extend ext = addr.extend();
+    Shift shift = addr.shift();
+    unsigned shift_amount = addr.shift_amount();
+
+    // LSL is encoded in the option field as UXTX.
+    if (shift == LSL) {
+      ext = UXTX;
+    }
+
+    // Shifts are encoded in one bit, indicating a left shift by the memory
+    // access size.
+    ASSERT((shift_amount == 0) ||
+           (shift_amount == static_cast<unsigned>(CalcLSDataSize(op))));
+    Emit(LoadStoreRegisterOffsetFixed | memop | Rm(addr.regoffset()) |
+         ExtendMode(ext) | ImmShiftLS((shift_amount > 0) ? 1 : 0));
+  } else {
+    // Pre-index and post-index modes.
+    ASSERT(!rt.Is(addr.base()));
+    if (IsImmLSUnscaled(offset)) {
+      if (addr.IsPreIndex()) {
+        Emit(LoadStorePreIndexFixed | memop | ImmLS(offset));
+      } else {
+        ASSERT(addr.IsPostIndex());
+        Emit(LoadStorePostIndexFixed | memop | ImmLS(offset));
+      }
+    } else {
+      // This case is handled in the macro assembler.
+      UNREACHABLE();
+    }
+  }
+}
+
+
+bool Assembler::IsImmLSUnscaled(ptrdiff_t offset) {
+  return is_int9(offset);
+}
+
+
+bool Assembler::IsImmLSScaled(ptrdiff_t offset, LSDataSize size) {
+  bool offset_is_size_multiple = (((offset >> size) << size) == offset);
+  return offset_is_size_multiple && is_uint12(offset >> size);
+}
+
+
+void Assembler::LoadLiteral(const CPURegister& rt, int offset_from_pc) {
+  ASSERT((offset_from_pc & ((1 << kLiteralEntrySizeLog2) - 1)) == 0);
+  // The pattern 'ldr xzr, #offset' is used to indicate the beginning of a
+  // constant pool. It should not be emitted.
+  ASSERT(!rt.Is(xzr));
+  Emit(LDR_x_lit |
+       ImmLLiteral(offset_from_pc >> kLiteralEntrySizeLog2) |
+       Rt(rt));
+}
+
+
+void Assembler::LoadRelocatedValue(const CPURegister& rt,
+                                   const Operand& operand,
+                                   LoadLiteralOp op) {
+  int64_t imm = operand.immediate();
+  ASSERT(is_int32(imm) || is_uint32(imm) || (rt.Is64Bits()));
+  RecordRelocInfo(operand.rmode(), imm);
+  BlockConstPoolFor(1);
+  Emit(op | ImmLLiteral(0) | Rt(rt));
+}
+
+
+// Test if a given value can be encoded in the immediate field of a logical
+// instruction.
+// If it can be encoded, the function returns true, and values pointed to by n,
+// imm_s and imm_r are updated with immediates encoded in the format required
+// by the corresponding fields in the logical instruction.
+// If it can not be encoded, the function returns false, and the values pointed
+// to by n, imm_s and imm_r are undefined.
+bool Assembler::IsImmLogical(uint64_t value,
+                             unsigned width,
+                             unsigned* n,
+                             unsigned* imm_s,
+                             unsigned* imm_r) {
+  ASSERT((n != NULL) && (imm_s != NULL) && (imm_r != NULL));
+  ASSERT((width == kWRegSize) || (width == kXRegSize));
+
+  // Logical immediates are encoded using parameters n, imm_s and imm_r using
+  // the following table:
+  //
+  //  N   imms    immr    size        S             R
+  //  1  ssssss  rrrrrr    64    UInt(ssssss)  UInt(rrrrrr)
+  //  0  0sssss  xrrrrr    32    UInt(sssss)   UInt(rrrrr)
+  //  0  10ssss  xxrrrr    16    UInt(ssss)    UInt(rrrr)
+  //  0  110sss  xxxrrr     8    UInt(sss)     UInt(rrr)
+  //  0  1110ss  xxxxrr     4    UInt(ss)      UInt(rr)
+  //  0  11110s  xxxxxr     2    UInt(s)       UInt(r)
+  // (s bits must not be all set)
+  //
+  // A pattern is constructed of size bits, where the least significant S+1
+  // bits are set. The pattern is rotated right by R, and repeated across a
+  // 32 or 64-bit value, depending on destination register width.
+  //
+  // To test if an arbitary immediate can be encoded using this scheme, an
+  // iterative algorithm is used.
+  //
+  // TODO(mcapewel) This code does not consider using X/W register overlap to
+  // support 64-bit immediates where the top 32-bits are zero, and the bottom
+  // 32-bits are an encodable logical immediate.
+
+  // 1. If the value has all set or all clear bits, it can't be encoded.
+  if ((value == 0) || (value == 0xffffffffffffffffUL) ||
+      ((width == kWRegSize) && (value == 0xffffffff))) {
+    return false;
+  }
+
+  unsigned lead_zero = CountLeadingZeros(value, width);
+  unsigned lead_one = CountLeadingZeros(~value, width);
+  unsigned trail_zero = CountTrailingZeros(value, width);
+  unsigned trail_one = CountTrailingZeros(~value, width);
+  unsigned set_bits = CountSetBits(value, width);
+
+  // The fixed bits in the immediate s field.
+  // If width == 64 (X reg), start at 0xFFFFFF80.
+  // If width == 32 (W reg), start at 0xFFFFFFC0, as the iteration for 64-bit
+  // widths won't be executed.
+  int imm_s_fixed = (width == kXRegSize) ? -128 : -64;
+  int imm_s_mask = 0x3F;
+
+  for (;;) {
+    // 2. If the value is two bits wide, it can be encoded.
+    if (width == 2) {
+      *n = 0;
+      *imm_s = 0x3C;
+      *imm_r = (value & 3) - 1;
+      return true;
+    }
+
+    *n = (width == 64) ? 1 : 0;
+    *imm_s = ((imm_s_fixed | (set_bits - 1)) & imm_s_mask);
+    if ((lead_zero + set_bits) == width) {
+      *imm_r = 0;
+    } else {
+      *imm_r = (lead_zero > 0) ? (width - trail_zero) : lead_one;
+    }
+
+    // 3. If the sum of leading zeros, trailing zeros and set bits is equal to
+    //    the bit width of the value, it can be encoded.
+    if (lead_zero + trail_zero + set_bits == width) {
+      return true;
+    }
+
+    // 4. If the sum of leading ones, trailing ones and unset bits in the
+    //    value is equal to the bit width of the value, it can be encoded.
+    if (lead_one + trail_one + (width - set_bits) == width) {
+      return true;
+    }
+
+    // 5. If the most-significant half of the bitwise value is equal to the
+    //    least-significant half, return to step 2 using the least-significant
+    //    half of the value.
+    uint64_t mask = (1UL << (width >> 1)) - 1;
+    if ((value & mask) == ((value >> (width >> 1)) & mask)) {
+      width >>= 1;
+      set_bits >>= 1;
+      imm_s_fixed >>= 1;
+      continue;
+    }
+
+    // 6. Otherwise, the value can't be encoded.
+    return false;
+  }
+}
+
+
+bool Assembler::IsImmConditionalCompare(int64_t immediate) {
+  return is_uint5(immediate);
+}
+
+
+bool Assembler::IsImmFP32(float imm) {
+  // Valid values will have the form:
+  // aBbb.bbbc.defg.h000.0000.0000.0000.0000
+  uint32_t bits = float_to_rawbits(imm);
+  // bits[19..0] are cleared.
+  if ((bits & 0x7ffff) != 0) {
+    return false;
+  }
+
+  // bits[29..25] are all set or all cleared.
+  uint32_t b_pattern = (bits >> 16) & 0x3e00;
+  if (b_pattern != 0 && b_pattern != 0x3e00) {
+    return false;
+  }
+
+  // bit[30] and bit[29] are opposite.
+  if (((bits ^ (bits << 1)) & 0x40000000) == 0) {
+    return false;
+  }
+
+  return true;
+}
+
+
+bool Assembler::IsImmFP64(double imm) {
+  // Valid values will have the form:
+  // aBbb.bbbb.bbcd.efgh.0000.0000.0000.0000
+  // 0000.0000.0000.0000.0000.0000.0000.0000
+  uint64_t bits = double_to_rawbits(imm);
+  // bits[47..0] are cleared.
+  if ((bits & 0xffffffffffffL) != 0) {
+    return false;
+  }
+
+  // bits[61..54] are all set or all cleared.
+  uint32_t b_pattern = (bits >> 48) & 0x3fc0;
+  if (b_pattern != 0 && b_pattern != 0x3fc0) {
+    return false;
+  }
+
+  // bit[62] and bit[61] are opposite.
+  if (((bits ^ (bits << 1)) & 0x4000000000000000L) == 0) {
+    return false;
+  }
+
+  return true;
+}
+
+
+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.
+
+  byte* buffer = reinterpret_cast<byte*>(buffer_);
+
+  // 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_ = reinterpret_cast<byte*>(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_pending_reloc_info_; i++) {
+    RelocInfo& rinfo = pending_reloc_info_[i];
+    ASSERT(rinfo.rmode() != RelocInfo::COMMENT &&
+           rinfo.rmode() != RelocInfo::POSITION);
+    if (rinfo.rmode() != RelocInfo::JS_RETURN) {
+      rinfo.set_pc(rinfo.pc() + pc_delta);
+    }
+  }
+}
+
+
+void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
+  // We do not try to reuse pool constants.
+  RelocInfo rinfo(reinterpret_cast<byte*>(pc_), rmode, data, NULL);
+  if (((rmode >= RelocInfo::JS_RETURN) &&
+       (rmode <= RelocInfo::DEBUG_BREAK_SLOT)) ||
+      (rmode == RelocInfo::CONST_POOL)) {
+    // Adjust code for new modes.
+    ASSERT(RelocInfo::IsDebugBreakSlot(rmode)
+           || RelocInfo::IsJSReturn(rmode)
+           || RelocInfo::IsComment(rmode)
+           || RelocInfo::IsPosition(rmode)
+           || RelocInfo::IsConstPool(rmode));
+    // These modes do not need an entry in the constant pool.
+  } else {
+    ASSERT(num_pending_reloc_info_ < kMaxNumPendingRelocInfo);
+    if (num_pending_reloc_info_ == 0) {
+      first_const_pool_use_ = pc_offset();
+    }
+    pending_reloc_info_[num_pending_reloc_info_++] = rinfo;
+    // Make sure the constant pool is not emitted in place of the next
+    // instruction for which we just recorded relocation info.
+    BlockConstPoolFor(1);
+  }
+
+  if (!RelocInfo::IsNone(rmode)) {
+    // Don't record external references unless the heap will be serialized.
+    if (rmode == RelocInfo::EXTERNAL_REFERENCE) {
+#ifdef DEBUG
+      if (!Serializer::enabled()) {
+        Serializer::TooLateToEnableNow();
+      }
+#endif
+      if (!Serializer::enabled() && !emit_debug_code()) {
+        return;
+      }
+    }
+    ASSERT(buffer_space() >= kMaxRelocSize);  // too late to grow buffer here
+    if (rmode == RelocInfo::CODE_TARGET_WITH_ID) {
+      RelocInfo reloc_info_with_ast_id(
+          reinterpret_cast<byte*>(pc_), rmode, RecordedAstId().ToInt(), NULL);
+      ClearRecordedAstId();
+      reloc_info_writer.Write(&reloc_info_with_ast_id);
+    } else {
+      reloc_info_writer.Write(&rinfo);
+    }
+  }
+}
+
+
+void Assembler::BlockConstPoolFor(int instructions) {
+  int pc_limit = pc_offset() + instructions * kInstructionSize;
+  if (no_const_pool_before_ < pc_limit) {
+    // If there are some pending entries, the constant pool cannot be blocked
+    // further than first_const_pool_use_ + kMaxDistToPool
+    ASSERT((num_pending_reloc_info_ == 0) ||
+           (pc_limit < (first_const_pool_use_ + kMaxDistToPool)));
+    no_const_pool_before_ = pc_limit;
+  }
+
+  if (next_buffer_check_ < no_const_pool_before_) {
+    next_buffer_check_ = no_const_pool_before_;
+  }
+}
+
+
+void Assembler::CheckConstPool(bool force_emit, bool require_jump) {
+  // Some short sequence of instruction mustn't be broken up by constant pool
+  // emission, such sequences are protected by calls to BlockConstPoolFor and
+  // BlockConstPoolScope.
+  if (is_const_pool_blocked()) {
+    // Something is wrong if emission is forced and blocked at the same time.
+    ASSERT(!force_emit);
+    return;
+  }
+
+  // There is nothing to do if there are no pending constant pool entries.
+  if (num_pending_reloc_info_ == 0)  {
+    // Calculate the offset of the next check.
+    next_buffer_check_ = pc_offset() + kCheckPoolInterval;
+    return;
+  }
+
+  // We emit a constant pool when:
+  //  * requested to do so by parameter force_emit (e.g. after each function).
+  //  * the distance to the first instruction accessing the constant pool is
+  //    kAvgDistToPool or more.
+  //  * no jump is required and the distance to the first instruction accessing
+  //    the constant pool is at least kMaxDistToPool / 2.
+  ASSERT(first_const_pool_use_ >= 0);
+  int dist = pc_offset() - first_const_pool_use_;
+  if (!force_emit && dist < kAvgDistToPool &&
+      (require_jump || (dist < (kMaxDistToPool / 2)))) {
+    return;
+  }
+
+  Label size_check;
+  bind(&size_check);
+
+  // Check that the code buffer is large enough before emitting the constant
+  // pool (include the jump over the pool, the constant pool marker, the
+  // constant pool guard, and the gap to the relocation information).
+  int jump_instr = require_jump ? kInstructionSize : 0;
+  int size_pool_marker = kInstructionSize;
+  int size_pool_guard = kInstructionSize;
+  int pool_size = jump_instr + size_pool_marker + size_pool_guard +
+    num_pending_reloc_info_ * kPointerSize;
+  int needed_space = pool_size + kGap;
+  while (buffer_space() <= needed_space) {
+    GrowBuffer();
+  }
+
+  {
+    // Block recursive calls to CheckConstPool.
+    BlockConstPoolScope block_const_pool(this);
+    RecordComment("[ Constant Pool");
+    RecordConstPool(pool_size);
+
+    // Emit jump over constant pool if necessary.
+    Label after_pool;
+    if (require_jump) {
+      b(&after_pool);
+    }
+
+    // Emit a constant pool header. The header has two goals:
+    //  1) Encode the size of the constant pool, for use by the disassembler.
+    //  2) Terminate the program, to try to prevent execution from accidentally
+    //     flowing into the constant pool.
+    // The header is therefore made of two a64 instructions:
+    //   ldr xzr, #<size of the constant pool in 32-bit words>
+    //   blr xzr
+    // If executed the code will likely segfault and lr will point to the
+    // beginning of the constant pool.
+    // TODO(all): currently each relocated constant is 64 bits, consider adding
+    // support for 32-bit entries.
+    ConstantPoolMarker(2 * num_pending_reloc_info_);
+    ConstantPoolGuard();
+
+    // Emit constant pool entries.
+    for (int i = 0; i < num_pending_reloc_info_; i++) {
+      RelocInfo& rinfo = pending_reloc_info_[i];
+      ASSERT(rinfo.rmode() != RelocInfo::COMMENT &&
+             rinfo.rmode() != RelocInfo::POSITION &&
+             rinfo.rmode() != RelocInfo::STATEMENT_POSITION &&
+             rinfo.rmode() != RelocInfo::CONST_POOL);
+
+      Instruction* instr = reinterpret_cast<Instruction*>(rinfo.pc());
+      // Instruction to patch must be 'ldr rd, [pc, #offset]' with offset == 0.
+      ASSERT(instr->IsLdrLiteral() &&
+             instr->ImmLLiteral() == 0);
+
+      instr->SetImmPCOffsetTarget(reinterpret_cast<Instruction*>(pc_));
+      dc64(rinfo.data());
+    }
+
+    num_pending_reloc_info_ = 0;
+    first_const_pool_use_ = -1;
+
+    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() + kCheckPoolInterval;
+
+  ASSERT(SizeOfCodeGeneratedSince(&size_check) ==
+         static_cast<unsigned>(pool_size));
+}
+
+
+void Assembler::RecordComment(const char* msg) {
+  if (FLAG_code_comments) {
+    CheckBuffer();
+    RecordRelocInfo(RelocInfo::COMMENT, reinterpret_cast<intptr_t>(msg));
+  }
+}
+
+
+int Assembler::buffer_space() const {
+  return reloc_info_writer.pos() - reinterpret_cast<byte*>(pc_);
+}
+
+
+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::RecordConstPool(int size) {
+  // We only need this for debugger support, to correctly compute offsets in the
+  // code.
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  RecordRelocInfo(RelocInfo::CONST_POOL, static_cast<intptr_t>(size));
+#endif
+}
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_A64