Experimental parser: merge to r19637

src/a64/assembler-a64-inl.h

+// 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.
+
+#ifndef V8_A64_ASSEMBLER_A64_INL_H_
+#define V8_A64_ASSEMBLER_A64_INL_H_
+
+#include "a64/assembler-a64.h"
+#include "cpu.h"
+#include "debug.h"
+
+
+namespace v8 {
+namespace internal {
+
+
+void RelocInfo::apply(intptr_t delta) {
+  UNIMPLEMENTED();
+}
+
+
+void RelocInfo::set_target_address(Address target, WriteBarrierMode mode) {
+  ASSERT(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_));
+  Assembler::set_target_address_at(pc_, target);
+  if (mode == UPDATE_WRITE_BARRIER && host() != NULL && IsCodeTarget(rmode_)) {
+    Object* target_code = Code::GetCodeFromTargetAddress(target);
+    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
+        host(), this, HeapObject::cast(target_code));
+  }
+}
+
+
+inline unsigned CPURegister::code() const {
+  ASSERT(IsValid());
+  return reg_code;
+}
+
+
+inline CPURegister::RegisterType CPURegister::type() const {
+  ASSERT(IsValidOrNone());
+  return reg_type;
+}
+
+
+inline RegList CPURegister::Bit() const {
+  ASSERT(reg_code < (sizeof(RegList) * kBitsPerByte));
+  return IsValid() ? 1UL << reg_code : 0;
+}
+
+
+inline unsigned CPURegister::SizeInBits() const {
+  ASSERT(IsValid());
+  return reg_size;
+}
+
+
+inline int CPURegister::SizeInBytes() const {
+  ASSERT(IsValid());
+  ASSERT(SizeInBits() % 8 == 0);
+  return reg_size / 8;
+}
+
+
+inline bool CPURegister::Is32Bits() const {
+  ASSERT(IsValid());
+  return reg_size == 32;
+}
+
+
+inline bool CPURegister::Is64Bits() const {
+  ASSERT(IsValid());
+  return reg_size == 64;
+}
+
+
+inline bool CPURegister::IsValid() const {
+  if (IsValidRegister() || IsValidFPRegister()) {
+    ASSERT(!IsNone());
+    return true;
+  } else {
+    ASSERT(IsNone());
+    return false;
+  }
+}
+
+
+inline bool CPURegister::IsValidRegister() const {
+  return IsRegister() &&
+         ((reg_size == kWRegSize) || (reg_size == kXRegSize)) &&
+         ((reg_code < kNumberOfRegisters) || (reg_code == kSPRegInternalCode));
+}
+
+
+inline bool CPURegister::IsValidFPRegister() const {
+  return IsFPRegister() &&
+         ((reg_size == kSRegSize) || (reg_size == kDRegSize)) &&
+         (reg_code < kNumberOfFPRegisters);
+}
+
+
+inline bool CPURegister::IsNone() const {
+  // kNoRegister types should always have size 0 and code 0.
+  ASSERT((reg_type != kNoRegister) || (reg_code == 0));
+  ASSERT((reg_type != kNoRegister) || (reg_size == 0));
+
+  return reg_type == kNoRegister;
+}
+
+
+inline bool CPURegister::Is(const CPURegister& other) const {
+  ASSERT(IsValidOrNone() && other.IsValidOrNone());
+  return (reg_code == other.reg_code) && (reg_size == other.reg_size) &&
+         (reg_type == other.reg_type);
+}
+
+
+inline bool CPURegister::IsRegister() const {
+  return reg_type == kRegister;
+}
+
+
+inline bool CPURegister::IsFPRegister() const {
+  return reg_type == kFPRegister;
+}
+
+
+inline bool CPURegister::IsSameSizeAndType(const CPURegister& other) const {
+  return (reg_size == other.reg_size) && (reg_type == other.reg_type);
+}
+
+
+inline bool CPURegister::IsValidOrNone() const {
+  return IsValid() || IsNone();
+}
+
+
+inline bool CPURegister::IsZero() const {
+  ASSERT(IsValid());
+  return IsRegister() && (reg_code == kZeroRegCode);
+}
+
+
+inline bool CPURegister::IsSP() const {
+  ASSERT(IsValid());
+  return IsRegister() && (reg_code == kSPRegInternalCode);
+}
+
+
+inline void CPURegList::Combine(const CPURegList& other) {
+  ASSERT(IsValid());
+  ASSERT(other.type() == type_);
+  ASSERT(other.RegisterSizeInBits() == size_);
+  list_ |= other.list();
+}
+
+
+inline void CPURegList::Remove(const CPURegList& other) {
+  ASSERT(IsValid());
+  ASSERT(other.type() == type_);
+  ASSERT(other.RegisterSizeInBits() == size_);
+  list_ &= ~other.list();
+}
+
+
+inline void CPURegList::Combine(const CPURegister& other) {
+  ASSERT(other.type() == type_);
+  ASSERT(other.SizeInBits() == size_);
+  Combine(other.code());
+}
+
+
+inline void CPURegList::Remove(const CPURegister& other) {
+  ASSERT(other.type() == type_);
+  ASSERT(other.SizeInBits() == size_);
+  Remove(other.code());
+}
+
+
+inline void CPURegList::Combine(int code) {
+  ASSERT(IsValid());
+  ASSERT(CPURegister::Create(code, size_, type_).IsValid());
+  list_ |= (1UL << code);
+}
+
+
+inline void CPURegList::Remove(int code) {
+  ASSERT(IsValid());
+  ASSERT(CPURegister::Create(code, size_, type_).IsValid());
+  list_ &= ~(1UL << code);
+}
+
+
+inline Register Register::XRegFromCode(unsigned code) {
+  // This function returns the zero register when code = 31. The stack pointer
+  // can not be returned.
+  ASSERT(code < kNumberOfRegisters);
+  return Register::Create(code, kXRegSize);
+}
+
+
+inline Register Register::WRegFromCode(unsigned code) {
+  ASSERT(code < kNumberOfRegisters);
+  return Register::Create(code, kWRegSize);
+}
+
+
+inline FPRegister FPRegister::SRegFromCode(unsigned code) {
+  ASSERT(code < kNumberOfFPRegisters);
+  return FPRegister::Create(code, kSRegSize);
+}
+
+
+inline FPRegister FPRegister::DRegFromCode(unsigned code) {
+  ASSERT(code < kNumberOfFPRegisters);
+  return FPRegister::Create(code, kDRegSize);
+}
+
+
+inline Register CPURegister::W() const {
+  ASSERT(IsValidRegister());
+  return Register::WRegFromCode(reg_code);
+}
+
+
+inline Register CPURegister::X() const {
+  ASSERT(IsValidRegister());
+  return Register::XRegFromCode(reg_code);
+}
+
+
+inline FPRegister CPURegister::S() const {
+  ASSERT(IsValidFPRegister());
+  return FPRegister::SRegFromCode(reg_code);
+}
+
+
+inline FPRegister CPURegister::D() const {
+  ASSERT(IsValidFPRegister());
+  return FPRegister::DRegFromCode(reg_code);
+}
+
+
+// Operand.
+template<typename T>
+Operand::Operand(Handle<T> value) : reg_(NoReg) {
+  initialize_handle(value);
+}
+
+
+// Default initializer is for int types
+template<typename int_t>
+struct OperandInitializer {
+  static const bool kIsIntType = true;
+  static inline RelocInfo::Mode rmode_for(int_t) {
+    return sizeof(int_t) == 8 ? RelocInfo::NONE64 : RelocInfo::NONE32;
+  }
+  static inline int64_t immediate_for(int_t t) {
+    STATIC_ASSERT(sizeof(int_t) <= 8);
+    return t;
+  }
+};
+
+
+template<>
+struct OperandInitializer<Smi*> {
+  static const bool kIsIntType = false;
+  static inline RelocInfo::Mode rmode_for(Smi* t) {
+    return RelocInfo::NONE64;
+  }
+  static inline int64_t immediate_for(Smi* t) {;
+    return reinterpret_cast<int64_t>(t);
+  }
+};
+
+
+template<>
+struct OperandInitializer<ExternalReference> {
+  static const bool kIsIntType = false;
+  static inline RelocInfo::Mode rmode_for(ExternalReference t) {
+    return RelocInfo::EXTERNAL_REFERENCE;
+  }
+  static inline int64_t immediate_for(ExternalReference t) {;
+    return reinterpret_cast<int64_t>(t.address());
+  }
+};
+
+
+template<typename T>
+Operand::Operand(T t)
+    : immediate_(OperandInitializer<T>::immediate_for(t)),
+      reg_(NoReg),
+      rmode_(OperandInitializer<T>::rmode_for(t)) {}
+
+
+template<typename T>
+Operand::Operand(T t, RelocInfo::Mode rmode)
+    : immediate_(OperandInitializer<T>::immediate_for(t)),
+      reg_(NoReg),
+      rmode_(rmode) {
+  STATIC_ASSERT(OperandInitializer<T>::kIsIntType);
+}
+
+
+Operand::Operand(Register reg, Shift shift, unsigned shift_amount)
+    : reg_(reg),
+      shift_(shift),
+      extend_(NO_EXTEND),
+      shift_amount_(shift_amount),
+      rmode_(reg.Is64Bits() ? RelocInfo::NONE64 : RelocInfo::NONE32) {
+  ASSERT(reg.Is64Bits() || (shift_amount < kWRegSize));
+  ASSERT(reg.Is32Bits() || (shift_amount < kXRegSize));
+  ASSERT(!reg.IsSP());
+}
+
+
+Operand::Operand(Register reg, Extend extend, unsigned shift_amount)
+    : reg_(reg),
+      shift_(NO_SHIFT),
+      extend_(extend),
+      shift_amount_(shift_amount),
+      rmode_(reg.Is64Bits() ? RelocInfo::NONE64 : RelocInfo::NONE32) {
+  ASSERT(reg.IsValid());
+  ASSERT(shift_amount <= 4);
+  ASSERT(!reg.IsSP());
+
+  // Extend modes SXTX and UXTX require a 64-bit register.
+  ASSERT(reg.Is64Bits() || ((extend != SXTX) && (extend != UXTX)));
+}
+
+
+bool Operand::IsImmediate() const {
+  return reg_.Is(NoReg);
+}
+
+
+bool Operand::IsShiftedRegister() const {
+  return reg_.IsValid() && (shift_ != NO_SHIFT);
+}
+
+
+bool Operand::IsExtendedRegister() const {
+  return reg_.IsValid() && (extend_ != NO_EXTEND);
+}
+
+
+bool Operand::IsZero() const {
+  if (IsImmediate()) {
+    return immediate() == 0;
+  } else {
+    return reg().IsZero();
+  }
+}
+
+
+Operand Operand::ToExtendedRegister() const {
+  ASSERT(IsShiftedRegister());
+  ASSERT((shift_ == LSL) && (shift_amount_ <= 4));
+  return Operand(reg_, reg_.Is64Bits() ? UXTX : UXTW, shift_amount_);
+}
+
+
+int64_t Operand::immediate() const {
+  ASSERT(IsImmediate());
+  return immediate_;
+}
+
+
+Register Operand::reg() const {
+  ASSERT(IsShiftedRegister() || IsExtendedRegister());
+  return reg_;
+}
+
+
+Shift Operand::shift() const {
+  ASSERT(IsShiftedRegister());
+  return shift_;
+}
+
+
+Extend Operand::extend() const {
+  ASSERT(IsExtendedRegister());
+  return extend_;
+}
+
+
+unsigned Operand::shift_amount() const {
+  ASSERT(IsShiftedRegister() || IsExtendedRegister());
+  return shift_amount_;
+}
+
+
+Operand Operand::UntagSmi(Register smi) {
+  ASSERT(smi.Is64Bits());
+  return Operand(smi, ASR, kSmiShift);
+}
+
+
+Operand Operand::UntagSmiAndScale(Register smi, int scale) {
+  ASSERT(smi.Is64Bits());
+  ASSERT((scale >= 0) && (scale <= (64 - kSmiValueSize)));
+  if (scale > kSmiShift) {
+    return Operand(smi, LSL, scale - kSmiShift);
+  } else if (scale < kSmiShift) {
+    return Operand(smi, ASR, kSmiShift - scale);
+  }
+  return Operand(smi);
+}
+
+
+MemOperand::MemOperand(Register base, ptrdiff_t offset, AddrMode addrmode)
+  : base_(base), regoffset_(NoReg), offset_(offset), addrmode_(addrmode),
+    shift_(NO_SHIFT), extend_(NO_EXTEND), shift_amount_(0) {
+  ASSERT(base.Is64Bits() && !base.IsZero());
+}
+
+
+MemOperand::MemOperand(Register base,
+                       Register regoffset,
+                       Extend extend,
+                       unsigned shift_amount)
+  : base_(base), regoffset_(regoffset), offset_(0), addrmode_(Offset),
+    shift_(NO_SHIFT), extend_(extend), shift_amount_(shift_amount) {
+  ASSERT(base.Is64Bits() && !base.IsZero());
+  ASSERT(!regoffset.IsSP());
+  ASSERT((extend == UXTW) || (extend == SXTW) || (extend == SXTX));
+
+  // SXTX extend mode requires a 64-bit offset register.
+  ASSERT(regoffset.Is64Bits() || (extend != SXTX));
+}
+
+
+MemOperand::MemOperand(Register base,
+                       Register regoffset,
+                       Shift shift,
+                       unsigned shift_amount)
+  : base_(base), regoffset_(regoffset), offset_(0), addrmode_(Offset),
+    shift_(shift), extend_(NO_EXTEND), shift_amount_(shift_amount) {
+  ASSERT(base.Is64Bits() && !base.IsZero());
+  ASSERT(regoffset.Is64Bits() && !regoffset.IsSP());
+  ASSERT(shift == LSL);
+}
+
+
+MemOperand::MemOperand(Register base, const Operand& offset, AddrMode addrmode)
+  : base_(base), addrmode_(addrmode) {
+  ASSERT(base.Is64Bits() && !base.IsZero());
+
+  if (offset.IsImmediate()) {
+    offset_ = offset.immediate();
+
+    regoffset_ = NoReg;
+  } else if (offset.IsShiftedRegister()) {
+    ASSERT(addrmode == Offset);
+
+    regoffset_ = offset.reg();
+    shift_= offset.shift();
+    shift_amount_ = offset.shift_amount();
+
+    extend_ = NO_EXTEND;
+    offset_ = 0;
+
+    // These assertions match those in the shifted-register constructor.
+    ASSERT(regoffset_.Is64Bits() && !regoffset_.IsSP());
+    ASSERT(shift_ == LSL);
+  } else {
+    ASSERT(offset.IsExtendedRegister());
+    ASSERT(addrmode == Offset);
+
+    regoffset_ = offset.reg();
+    extend_ = offset.extend();
+    shift_amount_ = offset.shift_amount();
+
+    shift_= NO_SHIFT;
+    offset_ = 0;
+
+    // These assertions match those in the extended-register constructor.
+    ASSERT(!regoffset_.IsSP());
+    ASSERT((extend_ == UXTW) || (extend_ == SXTW) || (extend_ == SXTX));
+    ASSERT((regoffset_.Is64Bits() || (extend_ != SXTX)));
+  }
+}
+
+bool MemOperand::IsImmediateOffset() const {
+  return (addrmode_ == Offset) && regoffset_.Is(NoReg);
+}
+
+
+bool MemOperand::IsRegisterOffset() const {
+  return (addrmode_ == Offset) && !regoffset_.Is(NoReg);
+}
+
+
+bool MemOperand::IsPreIndex() const {
+  return addrmode_ == PreIndex;
+}
+
+
+bool MemOperand::IsPostIndex() const {
+  return addrmode_ == PostIndex;
+}
+
+Operand MemOperand::OffsetAsOperand() const {
+  if (IsImmediateOffset()) {
+    return offset();
+  } else {
+    ASSERT(IsRegisterOffset());
+    if (extend() == NO_EXTEND) {
+      return Operand(regoffset(), shift(), shift_amount());
+    } else {
+      return Operand(regoffset(), extend(), shift_amount());
+    }
+  }
+}
+
+
+void Assembler::Unreachable() {
+#ifdef USE_SIMULATOR
+  debug("UNREACHABLE", __LINE__, BREAK);
+#else
+  // Crash by branching to 0. lr now points near the fault.
+  Emit(BLR | Rn(xzr));
+#endif
+}
+
+
+Address Assembler::target_pointer_address_at(Address pc) {
+  Instruction* instr = reinterpret_cast<Instruction*>(pc);
+  ASSERT(instr->IsLdrLiteralX());
+  return reinterpret_cast<Address>(instr->ImmPCOffsetTarget());
+}
+
+
+// Read/Modify the code target address in the branch/call instruction at pc.
+Address Assembler::target_address_at(Address pc) {
+  return Memory::Address_at(target_pointer_address_at(pc));
+}
+
+
+Address Assembler::target_address_from_return_address(Address pc) {
+  // Returns the address of the call target from the return address that will
+  // be returned to after a call.
+  // Call sequence on A64 is:
+  //  ldr ip0, #... @ load from literal pool
+  //  blr ip0
+  Address candidate = pc - 2 * kInstructionSize;
+  Instruction* instr = reinterpret_cast<Instruction*>(candidate);
+  USE(instr);
+  ASSERT(instr->IsLdrLiteralX());
+  return candidate;
+}
+
+
+Address Assembler::return_address_from_call_start(Address pc) {
+  // The call, generated by MacroAssembler::Call, is one of two possible
+  // sequences:
+  //
+  // Without relocation:
+  //  movz  ip0, #(target & 0x000000000000ffff)
+  //  movk  ip0, #(target & 0x00000000ffff0000)
+  //  movk  ip0, #(target & 0x0000ffff00000000)
+  //  movk  ip0, #(target & 0xffff000000000000)
+  //  blr   ip0
+  //
+  // With relocation:
+  //  ldr   ip0, =target
+  //  blr   ip0
+  //
+  // The return address is immediately after the blr instruction in both cases,
+  // so it can be found by adding the call size to the address at the start of
+  // the call sequence.
+  STATIC_ASSERT(Assembler::kCallSizeWithoutRelocation == 5 * kInstructionSize);
+  STATIC_ASSERT(Assembler::kCallSizeWithRelocation == 2 * kInstructionSize);
+
+  Instruction* instr = reinterpret_cast<Instruction*>(pc);
+  if (instr->IsMovz()) {
+    // Verify the instruction sequence.
+    ASSERT(instr->following(1)->IsMovk());
+    ASSERT(instr->following(2)->IsMovk());
+    ASSERT(instr->following(3)->IsMovk());
+    ASSERT(instr->following(4)->IsBranchAndLinkToRegister());
+    return pc + Assembler::kCallSizeWithoutRelocation;
+  } else {
+    // Verify the instruction sequence.
+    ASSERT(instr->IsLdrLiteralX());
+    ASSERT(instr->following(1)->IsBranchAndLinkToRegister());
+    return pc + Assembler::kCallSizeWithRelocation;
+  }
+}
+
+
+void Assembler::deserialization_set_special_target_at(
+    Address constant_pool_entry, Address target) {
+  Memory::Address_at(constant_pool_entry) = target;
+}
+
+
+void Assembler::set_target_address_at(Address pc, Address target) {
+  Memory::Address_at(target_pointer_address_at(pc)) = target;
+  // Intuitively, we would think it is necessary to always flush the
+  // instruction cache after patching a target address in the code as follows:
+  //   CPU::FlushICache(pc, sizeof(target));
+  // However, on ARM, an instruction is actually patched in the case of
+  // embedded constants of the form:
+  // ldr   ip, [pc, #...]
+  // since the instruction accessing this address in the constant pool remains
+  // unchanged, a flush is not required.
+}
+
+
+int RelocInfo::target_address_size() {
+  return kPointerSize;
+}
+
+
+Address RelocInfo::target_address() {
+  ASSERT(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_));
+  return Assembler::target_address_at(pc_);
+}
+
+
+Address RelocInfo::target_address_address() {
+  ASSERT(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_)
+                              || rmode_ == EMBEDDED_OBJECT
+                              || rmode_ == EXTERNAL_REFERENCE);
+  return Assembler::target_pointer_address_at(pc_);
+}
+
+
+Object* RelocInfo::target_object() {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  return reinterpret_cast<Object*>(Assembler::target_address_at(pc_));
+}
+
+
+Handle<Object> RelocInfo::target_object_handle(Assembler* origin) {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  return Handle<Object>(reinterpret_cast<Object**>(
+      Assembler::target_address_at(pc_)));
+}
+
+
+void RelocInfo::set_target_object(Object* target, WriteBarrierMode mode) {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  ASSERT(!target->IsConsString());
+  Assembler::set_target_address_at(pc_, reinterpret_cast<Address>(target));
+  if (mode == UPDATE_WRITE_BARRIER &&
+      host() != NULL &&
+      target->IsHeapObject()) {
+    host()->GetHeap()->incremental_marking()->RecordWrite(
+        host(), &Memory::Object_at(pc_), HeapObject::cast(target));
+  }
+}
+
+
+Address RelocInfo::target_reference() {
+  ASSERT(rmode_ == EXTERNAL_REFERENCE);
+  return Assembler::target_address_at(pc_);
+}
+
+
+Address RelocInfo::target_runtime_entry(Assembler* origin) {
+  ASSERT(IsRuntimeEntry(rmode_));
+  return target_address();
+}
+
+
+void RelocInfo::set_target_runtime_entry(Address target,
+                                         WriteBarrierMode mode) {
+  ASSERT(IsRuntimeEntry(rmode_));
+  if (target_address() != target) set_target_address(target, mode);
+}
+
+
+Handle<Cell> RelocInfo::target_cell_handle() {
+  UNIMPLEMENTED();
+  Cell *null_cell = NULL;
+  return Handle<Cell>(null_cell);
+}
+
+
+Cell* RelocInfo::target_cell() {
+  ASSERT(rmode_ == RelocInfo::CELL);
+  return Cell::FromValueAddress(Memory::Address_at(pc_));
+}
+
+
+void RelocInfo::set_target_cell(Cell* cell, WriteBarrierMode mode) {
+  UNIMPLEMENTED();
+}
+
+
+static const int kCodeAgeSequenceSize = 5 * kInstructionSize;
+static const int kCodeAgeStubEntryOffset = 3 * kInstructionSize;
+
+
+Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
+  UNREACHABLE();  // This should never be reached on A64.
+  return Handle<Object>();
+}
+
+
+Code* RelocInfo::code_age_stub() {
+  ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
+  ASSERT(!Code::IsYoungSequence(pc_));
+  // Read the stub entry point from the code age sequence.
+  Address stub_entry_address = pc_ + kCodeAgeStubEntryOffset;
+  return Code::GetCodeFromTargetAddress(Memory::Address_at(stub_entry_address));
+}
+
+
+void RelocInfo::set_code_age_stub(Code* stub) {
+  ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
+  ASSERT(!Code::IsYoungSequence(pc_));
+  // Overwrite the stub entry point in the code age sequence. This is loaded as
+  // a literal so there is no need to call FlushICache here.
+  Address stub_entry_address = pc_ + kCodeAgeStubEntryOffset;
+  Memory::Address_at(stub_entry_address) = stub->instruction_start();
+}
+
+
+Address RelocInfo::call_address() {
+  ASSERT((IsJSReturn(rmode()) && IsPatchedReturnSequence()) ||
+         (IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence()));
+  // For the above sequences the Relocinfo points to the load literal loading
+  // the call address.
+  return Assembler::target_address_at(pc_);
+}
+
+
+void RelocInfo::set_call_address(Address target) {
+  ASSERT((IsJSReturn(rmode()) && IsPatchedReturnSequence()) ||
+         (IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence()));
+  Assembler::set_target_address_at(pc_, target);
+  if (host() != NULL) {
+    Object* target_code = Code::GetCodeFromTargetAddress(target);
+    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
+        host(), this, HeapObject::cast(target_code));
+  }
+}
+
+
+void RelocInfo::WipeOut() {
+  ASSERT(IsEmbeddedObject(rmode_) ||
+         IsCodeTarget(rmode_) ||
+         IsRuntimeEntry(rmode_) ||
+         IsExternalReference(rmode_));
+  Assembler::set_target_address_at(pc_, NULL);
+}
+
+
+bool RelocInfo::IsPatchedReturnSequence() {
+  // The sequence must be:
+  //   ldr ip0, [pc, #offset]
+  //   blr ip0
+  // See a64/debug-a64.cc BreakLocationIterator::SetDebugBreakAtReturn().
+  Instruction* i1 = reinterpret_cast<Instruction*>(pc_);
+  Instruction* i2 = i1->following();
+  return i1->IsLdrLiteralX() && (i1->Rt() == ip0.code()) &&
+         i2->IsBranchAndLinkToRegister() && (i2->Rn() == ip0.code());
+}
+
+
+bool RelocInfo::IsPatchedDebugBreakSlotSequence() {
+  Instruction* current_instr = reinterpret_cast<Instruction*>(pc_);
+  return !current_instr->IsNop(Assembler::DEBUG_BREAK_NOP);
+}
+
+
+void RelocInfo::Visit(Isolate* isolate, ObjectVisitor* visitor) {
+  RelocInfo::Mode mode = rmode();
+  if (mode == RelocInfo::EMBEDDED_OBJECT) {
+    visitor->VisitEmbeddedPointer(this);
+  } else if (RelocInfo::IsCodeTarget(mode)) {
+    visitor->VisitCodeTarget(this);
+  } else if (mode == RelocInfo::CELL) {
+    visitor->VisitCell(this);
+  } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
+    visitor->VisitExternalReference(this);
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  } else if (((RelocInfo::IsJSReturn(mode) &&
+              IsPatchedReturnSequence()) ||
+             (RelocInfo::IsDebugBreakSlot(mode) &&
+              IsPatchedDebugBreakSlotSequence())) &&
+             isolate->debug()->has_break_points()) {
+    visitor->VisitDebugTarget(this);
+#endif
+  } else if (RelocInfo::IsRuntimeEntry(mode)) {
+    visitor->VisitRuntimeEntry(this);
+  }
+}
+
+
+template<typename StaticVisitor>
+void RelocInfo::Visit(Heap* heap) {
+  RelocInfo::Mode mode = rmode();
+  if (mode == RelocInfo::EMBEDDED_OBJECT) {
+    StaticVisitor::VisitEmbeddedPointer(heap, this);
+  } else if (RelocInfo::IsCodeTarget(mode)) {
+    StaticVisitor::VisitCodeTarget(heap, this);
+  } else if (mode == RelocInfo::CELL) {
+    StaticVisitor::VisitCell(heap, this);
+  } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
+    StaticVisitor::VisitExternalReference(this);
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  } else if (heap->isolate()->debug()->has_break_points() &&
+             ((RelocInfo::IsJSReturn(mode) &&
+              IsPatchedReturnSequence()) ||
+             (RelocInfo::IsDebugBreakSlot(mode) &&
+              IsPatchedDebugBreakSlotSequence()))) {
+    StaticVisitor::VisitDebugTarget(heap, this);
+#endif
+  } else if (RelocInfo::IsRuntimeEntry(mode)) {
+    StaticVisitor::VisitRuntimeEntry(this);
+  }
+}
+
+
+LoadStoreOp Assembler::LoadOpFor(const CPURegister& rt) {
+  ASSERT(rt.IsValid());
+  if (rt.IsRegister()) {
+    return rt.Is64Bits() ? LDR_x : LDR_w;
+  } else {
+    ASSERT(rt.IsFPRegister());
+    return rt.Is64Bits() ? LDR_d : LDR_s;
+  }
+}
+
+
+LoadStorePairOp Assembler::LoadPairOpFor(const CPURegister& rt,
+                                         const CPURegister& rt2) {
+  ASSERT(AreSameSizeAndType(rt, rt2));
+  USE(rt2);
+  if (rt.IsRegister()) {
+    return rt.Is64Bits() ? LDP_x : LDP_w;
+  } else {
+    ASSERT(rt.IsFPRegister());
+    return rt.Is64Bits() ? LDP_d : LDP_s;
+  }
+}
+
+
+LoadStoreOp Assembler::StoreOpFor(const CPURegister& rt) {
+  ASSERT(rt.IsValid());
+  if (rt.IsRegister()) {
+    return rt.Is64Bits() ? STR_x : STR_w;
+  } else {
+    ASSERT(rt.IsFPRegister());
+    return rt.Is64Bits() ? STR_d : STR_s;
+  }
+}
+
+
+LoadStorePairOp Assembler::StorePairOpFor(const CPURegister& rt,
+                                          const CPURegister& rt2) {
+  ASSERT(AreSameSizeAndType(rt, rt2));
+  USE(rt2);
+  if (rt.IsRegister()) {
+    return rt.Is64Bits() ? STP_x : STP_w;
+  } else {
+    ASSERT(rt.IsFPRegister());
+    return rt.Is64Bits() ? STP_d : STP_s;
+  }
+}
+
+
+LoadStorePairNonTemporalOp Assembler::LoadPairNonTemporalOpFor(
+    const CPURegister& rt, const CPURegister& rt2) {
+  ASSERT(AreSameSizeAndType(rt, rt2));
+  USE(rt2);
+  if (rt.IsRegister()) {
+    return rt.Is64Bits() ? LDNP_x : LDNP_w;
+  } else {
+    ASSERT(rt.IsFPRegister());
+    return rt.Is64Bits() ? LDNP_d : LDNP_s;
+  }
+}
+
+
+LoadStorePairNonTemporalOp Assembler::StorePairNonTemporalOpFor(
+    const CPURegister& rt, const CPURegister& rt2) {
+  ASSERT(AreSameSizeAndType(rt, rt2));
+  USE(rt2);
+  if (rt.IsRegister()) {
+    return rt.Is64Bits() ? STNP_x : STNP_w;
+  } else {
+    ASSERT(rt.IsFPRegister());
+    return rt.Is64Bits() ? STNP_d : STNP_s;
+  }
+}
+
+
+int Assembler::LinkAndGetInstructionOffsetTo(Label* label) {
+  ASSERT(kStartOfLabelLinkChain == 0);
+  int offset = LinkAndGetByteOffsetTo(label);
+  ASSERT(IsAligned(offset, kInstructionSize));
+  return offset >> kInstructionSizeLog2;
+}
+
+
+Instr Assembler::Flags(FlagsUpdate S) {
+  if (S == SetFlags) {
+    return 1 << FlagsUpdate_offset;
+  } else if (S == LeaveFlags) {
+    return 0 << FlagsUpdate_offset;
+  }
+  UNREACHABLE();
+  return 0;
+}
+
+
+Instr Assembler::Cond(Condition cond) {
+  return cond << Condition_offset;
+}
+
+
+Instr Assembler::ImmPCRelAddress(int imm21) {
+  CHECK(is_int21(imm21));
+  Instr imm = static_cast<Instr>(truncate_to_int21(imm21));
+  Instr immhi = (imm >> ImmPCRelLo_width) << ImmPCRelHi_offset;
+  Instr immlo = imm << ImmPCRelLo_offset;
+  return (immhi & ImmPCRelHi_mask) | (immlo & ImmPCRelLo_mask);
+}
+
+
+Instr Assembler::ImmUncondBranch(int imm26) {
+  CHECK(is_int26(imm26));
+  return truncate_to_int26(imm26) << ImmUncondBranch_offset;
+}
+
+
+Instr Assembler::ImmCondBranch(int imm19) {
+  CHECK(is_int19(imm19));
+  return truncate_to_int19(imm19) << ImmCondBranch_offset;
+}
+
+
+Instr Assembler::ImmCmpBranch(int imm19) {
+  CHECK(is_int19(imm19));
+  return truncate_to_int19(imm19) << ImmCmpBranch_offset;
+}
+
+
+Instr Assembler::ImmTestBranch(int imm14) {
+  CHECK(is_int14(imm14));
+  return truncate_to_int14(imm14) << ImmTestBranch_offset;
+}
+
+
+Instr Assembler::ImmTestBranchBit(unsigned bit_pos) {
+  ASSERT(is_uint6(bit_pos));
+  // Subtract five from the shift offset, as we need bit 5 from bit_pos.
+  unsigned b5 = bit_pos << (ImmTestBranchBit5_offset - 5);
+  unsigned b40 = bit_pos << ImmTestBranchBit40_offset;
+  b5 &= ImmTestBranchBit5_mask;
+  b40 &= ImmTestBranchBit40_mask;
+  return b5 | b40;
+}
+
+
+Instr Assembler::SF(Register rd) {
+    return rd.Is64Bits() ? SixtyFourBits : ThirtyTwoBits;
+}
+
+
+Instr Assembler::ImmAddSub(int64_t imm) {
+  ASSERT(IsImmAddSub(imm));
+  if (is_uint12(imm)) {  // No shift required.
+    return imm << ImmAddSub_offset;
+  } else {
+    return ((imm >> 12) << ImmAddSub_offset) | (1 << ShiftAddSub_offset);
+  }
+}
+
+
+Instr Assembler::ImmS(unsigned imms, unsigned reg_size) {
+  ASSERT(((reg_size == kXRegSize) && is_uint6(imms)) ||
+         ((reg_size == kWRegSize) && is_uint5(imms)));
+  USE(reg_size);
+  return imms << ImmS_offset;
+}
+
+
+Instr Assembler::ImmR(unsigned immr, unsigned reg_size) {
+  ASSERT(((reg_size == kXRegSize) && is_uint6(immr)) ||
+         ((reg_size == kWRegSize) && is_uint5(immr)));
+  USE(reg_size);
+  ASSERT(is_uint6(immr));
+  return immr << ImmR_offset;
+}
+
+
+Instr Assembler::ImmSetBits(unsigned imms, unsigned reg_size) {
+  ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize));
+  ASSERT(is_uint6(imms));
+  ASSERT((reg_size == kXRegSize) || is_uint6(imms + 3));
+  USE(reg_size);
+  return imms << ImmSetBits_offset;
+}
+
+
+Instr Assembler::ImmRotate(unsigned immr, unsigned reg_size) {
+  ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize));
+  ASSERT(((reg_size == kXRegSize) && is_uint6(immr)) ||
+         ((reg_size == kWRegSize) && is_uint5(immr)));
+  USE(reg_size);
+  return immr << ImmRotate_offset;
+}
+
+
+Instr Assembler::ImmLLiteral(int imm19) {
+  CHECK(is_int19(imm19));
+  return truncate_to_int19(imm19) << ImmLLiteral_offset;
+}
+
+
+Instr Assembler::BitN(unsigned bitn, unsigned reg_size) {
+  ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize));
+  ASSERT((reg_size == kXRegSize) || (bitn == 0));
+  USE(reg_size);
+  return bitn << BitN_offset;
+}
+
+
+Instr Assembler::ShiftDP(Shift shift) {
+  ASSERT(shift == LSL || shift == LSR || shift == ASR || shift == ROR);
+  return shift << ShiftDP_offset;
+}
+
+
+Instr Assembler::ImmDPShift(unsigned amount) {
+  ASSERT(is_uint6(amount));
+  return amount << ImmDPShift_offset;
+}
+
+
+Instr Assembler::ExtendMode(Extend extend) {
+  return extend << ExtendMode_offset;
+}
+
+
+Instr Assembler::ImmExtendShift(unsigned left_shift) {
+  ASSERT(left_shift <= 4);
+  return left_shift << ImmExtendShift_offset;
+}
+
+
+Instr Assembler::ImmCondCmp(unsigned imm) {
+  ASSERT(is_uint5(imm));
+  return imm << ImmCondCmp_offset;
+}
+
+
+Instr Assembler::Nzcv(StatusFlags nzcv) {
+  return ((nzcv >> Flags_offset) & 0xf) << Nzcv_offset;
+}
+
+
+Instr Assembler::ImmLSUnsigned(int imm12) {
+  ASSERT(is_uint12(imm12));
+  return imm12 << ImmLSUnsigned_offset;
+}
+
+
+Instr Assembler::ImmLS(int imm9) {
+  ASSERT(is_int9(imm9));
+  return truncate_to_int9(imm9) << ImmLS_offset;
+}
+
+
+Instr Assembler::ImmLSPair(int imm7, LSDataSize size) {
+  ASSERT(((imm7 >> size) << size) == imm7);
+  int scaled_imm7 = imm7 >> size;
+  ASSERT(is_int7(scaled_imm7));
+  return truncate_to_int7(scaled_imm7) << ImmLSPair_offset;
+}
+
+
+Instr Assembler::ImmShiftLS(unsigned shift_amount) {
+  ASSERT(is_uint1(shift_amount));
+  return shift_amount << ImmShiftLS_offset;
+}
+
+
+Instr Assembler::ImmException(int imm16) {
+  ASSERT(is_uint16(imm16));
+  return imm16 << ImmException_offset;
+}
+
+
+Instr Assembler::ImmSystemRegister(int imm15) {
+  ASSERT(is_uint15(imm15));
+  return imm15 << ImmSystemRegister_offset;
+}
+
+
+Instr Assembler::ImmHint(int imm7) {
+  ASSERT(is_uint7(imm7));
+  return imm7 << ImmHint_offset;
+}
+
+
+Instr Assembler::ImmBarrierDomain(int imm2) {
+  ASSERT(is_uint2(imm2));
+  return imm2 << ImmBarrierDomain_offset;
+}
+
+
+Instr Assembler::ImmBarrierType(int imm2) {
+  ASSERT(is_uint2(imm2));
+  return imm2 << ImmBarrierType_offset;
+}
+
+
+LSDataSize Assembler::CalcLSDataSize(LoadStoreOp op) {
+  ASSERT((SizeLS_offset + SizeLS_width) == (kInstructionSize * 8));
+  return static_cast<LSDataSize>(op >> SizeLS_offset);
+}
+
+
+Instr Assembler::ImmMoveWide(uint64_t imm) {
+  ASSERT(is_uint16(imm));
+  return imm << ImmMoveWide_offset;
+}
+
+
+Instr Assembler::ShiftMoveWide(int64_t shift) {
+  ASSERT(is_uint2(shift));
+  return shift << ShiftMoveWide_offset;
+}
+
+
+Instr Assembler::FPType(FPRegister fd) {
+  return fd.Is64Bits() ? FP64 : FP32;
+}
+
+
+Instr Assembler::FPScale(unsigned scale) {
+  ASSERT(is_uint6(scale));
+  return scale << FPScale_offset;
+}
+
+
+const Register& Assembler::AppropriateZeroRegFor(const CPURegister& reg) const {
+  return reg.Is64Bits() ? xzr : wzr;
+}
+
+
+void Assembler::LoadRelocated(const CPURegister& rt, const Operand& operand) {
+  LoadRelocatedValue(rt, operand, LDR_x_lit);
+}
+
+
+inline void Assembler::CheckBuffer() {
+  ASSERT(pc_ < (buffer_ + buffer_size_));
+  if (buffer_space() < kGap) {
+    GrowBuffer();
+  }
+  if (pc_offset() >= next_buffer_check_) {
+    CheckConstPool(false, true);
+  }
+}
+
+
+TypeFeedbackId Assembler::RecordedAstId() {
+  ASSERT(!recorded_ast_id_.IsNone());
+  return recorded_ast_id_;
+}
+
+
+void Assembler::ClearRecordedAstId() {
+  recorded_ast_id_ = TypeFeedbackId::None();
+}
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_A64_ASSEMBLER_A64_INL_H_