Merge experimental/a64 to bleeding_edge.

src/a64/assembler-a64.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_H_
+#define V8_A64_ASSEMBLER_A64_H_
+
+#include <list>
+
+#include "globals.h"
+#include "utils.h"
+#include "assembler.h"
+#include "serialize.h"
+#include "a64/instructions-a64.h"
+#include "a64/cpu-a64.h"
+
+
+namespace v8 {
+namespace internal {
+
+
+// -----------------------------------------------------------------------------
+// Registers.
+#define REGISTER_CODE_LIST(R)                                                  \
+R(0)  R(1)  R(2)  R(3)  R(4)  R(5)  R(6)  R(7)                                 \
+R(8)  R(9)  R(10) R(11) R(12) R(13) R(14) R(15)                                \
+R(16) R(17) R(18) R(19) R(20) R(21) R(22) R(23)                                \
+R(24) R(25) R(26) R(27) R(28) R(29) R(30) R(31)
+
+
+static const int kRegListSizeInBits = sizeof(RegList) * kBitsPerByte;
+
+
+// Some CPURegister methods can return Register and FPRegister types, so we
+// need to declare them in advance.
+class Register;
+class FPRegister;
+
+
+struct CPURegister {
+  enum RegisterType {
+    // The kInvalid value is used to detect uninitialized static instances,
+    // which are always zero-initialized before any constructors are called.
+    kInvalid = 0,
+    kRegister,
+    kFPRegister,
+    kNoRegister
+  };
+
+  static CPURegister Create(unsigned code, unsigned size, RegisterType type) {
+    CPURegister r = {code, size, type};
+    return r;
+  }
+
+  unsigned code() const;
+  RegisterType type() const;
+  RegList Bit() const;
+  unsigned SizeInBits() const;
+  int SizeInBytes() const;
+  bool Is32Bits() const;
+  bool Is64Bits() const;
+  bool IsValid() const;
+  bool IsValidOrNone() const;
+  bool IsValidRegister() const;
+  bool IsValidFPRegister() const;
+  bool IsNone() const;
+  bool Is(const CPURegister& other) const;
+
+  bool IsZero() const;
+  bool IsSP() const;
+
+  bool IsRegister() const;
+  bool IsFPRegister() const;
+
+  Register X() const;
+  Register W() const;
+  FPRegister D() const;
+  FPRegister S() const;
+
+  bool IsSameSizeAndType(const CPURegister& other) const;
+
+  // V8 compatibility.
+  bool is(const CPURegister& other) const { return Is(other); }
+  bool is_valid() const { return IsValid(); }
+
+  unsigned reg_code;
+  unsigned reg_size;
+  RegisterType reg_type;
+};
+
+
+struct Register : public CPURegister {
+  static Register Create(unsigned code, unsigned size) {
+    return CPURegister::Create(code, size, CPURegister::kRegister);
+  }
+
+  Register() {
+    reg_code = 0;
+    reg_size = 0;
+    reg_type = CPURegister::kNoRegister;
+  }
+
+  Register(const CPURegister& r) {  // NOLINT(runtime/explicit)
+    reg_code = r.reg_code;
+    reg_size = r.reg_size;
+    reg_type = r.reg_type;
+    ASSERT(IsValidOrNone());
+  }
+
+  bool IsValid() const {
+    ASSERT(IsRegister() || IsNone());
+    return IsValidRegister();
+  }
+
+  static Register XRegFromCode(unsigned code);
+  static Register WRegFromCode(unsigned code);
+
+  // Start of V8 compatibility section ---------------------
+  // These memebers are necessary for compilation.
+  // A few of them may be unused for now.
+
+  static const int kNumRegisters = kNumberOfRegisters;
+  static int NumRegisters() { return kNumRegisters; }
+
+  // We allow crankshaft to use the following registers:
+  //   - x0 to x15
+  //   - x18 to x24
+  //   - x27 (also context)
+  //
+  // TODO(all): Register x25 is currently free and could be available for
+  // crankshaft, but we don't use it as we might use it as a per function
+  // literal pool pointer in the future.
+  //
+  // TODO(all): Consider storing cp in x25 to have only two ranges.
+  // We split allocatable registers in three ranges called
+  //   - "low range"
+  //   - "high range"
+  //   - "context"
+  static const unsigned kAllocatableLowRangeBegin = 0;
+  static const unsigned kAllocatableLowRangeEnd = 15;
+  static const unsigned kAllocatableHighRangeBegin = 18;
+  static const unsigned kAllocatableHighRangeEnd = 24;
+  static const unsigned kAllocatableContext = 27;
+
+  // Gap between low and high ranges.
+  static const int kAllocatableRangeGapSize =
+      (kAllocatableHighRangeBegin - kAllocatableLowRangeEnd) - 1;
+
+  static const int kMaxNumAllocatableRegisters =
+      (kAllocatableLowRangeEnd - kAllocatableLowRangeBegin + 1) +
+      (kAllocatableHighRangeEnd - kAllocatableHighRangeBegin + 1) + 1;  // cp
+  static int NumAllocatableRegisters() { return kMaxNumAllocatableRegisters; }
+
+  // Return true if the register is one that crankshaft can allocate.
+  bool IsAllocatable() const {
+    return ((reg_code == kAllocatableContext) ||
+            (reg_code <= kAllocatableLowRangeEnd) ||
+            ((reg_code >= kAllocatableHighRangeBegin) &&
+             (reg_code <= kAllocatableHighRangeEnd)));
+  }
+
+  static Register FromAllocationIndex(unsigned index) {
+    ASSERT(index < static_cast<unsigned>(NumAllocatableRegisters()));
+    // cp is the last allocatable register.
+    if (index == (static_cast<unsigned>(NumAllocatableRegisters() - 1))) {
+      return from_code(kAllocatableContext);
+    }
+
+    // Handle low and high ranges.
+    return (index <= kAllocatableLowRangeEnd)
+        ? from_code(index)
+        : from_code(index + kAllocatableRangeGapSize);
+  }
+
+  static const char* AllocationIndexToString(int index) {
+    ASSERT((index >= 0) && (index < NumAllocatableRegisters()));
+    ASSERT((kAllocatableLowRangeBegin == 0) &&
+           (kAllocatableLowRangeEnd == 15) &&
+           (kAllocatableHighRangeBegin == 18) &&
+           (kAllocatableHighRangeEnd == 24) &&
+           (kAllocatableContext == 27));
+    const char* const names[] = {
+      "x0", "x1", "x2", "x3", "x4",
+      "x5", "x6", "x7", "x8", "x9",
+      "x10", "x11", "x12", "x13", "x14",
+      "x15", "x18", "x19", "x20", "x21",
+      "x22", "x23", "x24", "x27",
+    };
+    return names[index];
+  }
+
+  static int ToAllocationIndex(Register reg) {
+    ASSERT(reg.IsAllocatable());
+    unsigned code = reg.code();
+    if (code == kAllocatableContext) {
+      return NumAllocatableRegisters() - 1;
+    }
+
+    return (code <= kAllocatableLowRangeEnd)
+        ? code
+        : code - kAllocatableRangeGapSize;
+  }
+
+  static Register from_code(int code) {
+    // Always return an X register.
+    return Register::Create(code, kXRegSize);
+  }
+
+  // End of V8 compatibility section -----------------------
+};
+
+
+struct FPRegister : public CPURegister {
+  static FPRegister Create(unsigned code, unsigned size) {
+    return CPURegister::Create(code, size, CPURegister::kFPRegister);
+  }
+
+  FPRegister() {
+    reg_code = 0;
+    reg_size = 0;
+    reg_type = CPURegister::kNoRegister;
+  }
+
+  FPRegister(const CPURegister& r) {  // NOLINT(runtime/explicit)
+    reg_code = r.reg_code;
+    reg_size = r.reg_size;
+    reg_type = r.reg_type;
+    ASSERT(IsValidOrNone());
+  }
+
+  bool IsValid() const {
+    ASSERT(IsFPRegister() || IsNone());
+    return IsValidFPRegister();
+  }
+
+  static FPRegister SRegFromCode(unsigned code);
+  static FPRegister DRegFromCode(unsigned code);
+
+  // Start of V8 compatibility section ---------------------
+  static const int kMaxNumRegisters = kNumberOfFPRegisters;
+
+  // Crankshaft can use all the FP registers except:
+  //   - d29 which is used in crankshaft as a double scratch register
+  //   - d30 which is used to keep the 0 double value
+  //   - d31 which is used in the MacroAssembler as a double scratch register
+  static const int kNumReservedRegisters = 3;
+  static const int kMaxNumAllocatableRegisters =
+      kNumberOfFPRegisters - kNumReservedRegisters;
+  static int NumAllocatableRegisters() { return kMaxNumAllocatableRegisters; }
+  static const RegList kAllocatableFPRegisters =
+      (1 << kMaxNumAllocatableRegisters) - 1;
+
+  static FPRegister FromAllocationIndex(int index) {
+    ASSERT((index >= 0) && (index < NumAllocatableRegisters()));
+    return from_code(index);
+  }
+
+  static const char* AllocationIndexToString(int index) {
+    ASSERT((index >= 0) && (index < NumAllocatableRegisters()));
+    const char* const names[] = {
+      "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7",
+      "d8", "d9", "d10", "d11", "d12", "d13", "d14", "d15",
+      "d16", "d17", "d18", "d19", "d20", "d21", "d22", "d23",
+      "d24", "d25", "d26", "d27", "d28",
+    };
+    return names[index];
+  }
+
+  static int ToAllocationIndex(FPRegister reg) {
+    int code = reg.code();
+    ASSERT(code < NumAllocatableRegisters());
+    return code;
+  }
+
+  static FPRegister from_code(int code) {
+    // Always return a D register.
+    return FPRegister::Create(code, kDRegSize);
+  }
+  // End of V8 compatibility section -----------------------
+};
+
+
+STATIC_ASSERT(sizeof(CPURegister) == sizeof(Register));
+STATIC_ASSERT(sizeof(CPURegister) == sizeof(FPRegister));
+
+
+#if defined(A64_DEFINE_REG_STATICS)
+#define INITIALIZE_REGISTER(register_class, name, code, size, type)      \
+  const CPURegister init_##register_class##_##name = {code, size, type}; \
+  const register_class& name = *reinterpret_cast<const register_class*>( \
+                                    &init_##register_class##_##name)
+#define ALIAS_REGISTER(register_class, alias, name)                       \
+  const register_class& alias = *reinterpret_cast<const register_class*>( \
+                                     &init_##register_class##_##name)
+#else
+#define INITIALIZE_REGISTER(register_class, name, code, size, type) \
+  extern const register_class& name
+#define ALIAS_REGISTER(register_class, alias, name) \
+  extern const register_class& alias
+#endif  // defined(A64_DEFINE_REG_STATICS)
+
+// No*Reg is used to indicate an unused argument, or an error case. Note that
+// these all compare equal (using the Is() method). The Register and FPRegister
+// variants are provided for convenience.
+INITIALIZE_REGISTER(Register, NoReg, 0, 0, CPURegister::kNoRegister);
+INITIALIZE_REGISTER(FPRegister, NoFPReg, 0, 0, CPURegister::kNoRegister);
+INITIALIZE_REGISTER(CPURegister, NoCPUReg, 0, 0, CPURegister::kNoRegister);
+
+// v8 compatibility.
+INITIALIZE_REGISTER(Register, no_reg, 0, 0, CPURegister::kNoRegister);
+
+#define DEFINE_REGISTERS(N)                                                  \
+  INITIALIZE_REGISTER(Register, w##N, N, kWRegSize, CPURegister::kRegister); \
+  INITIALIZE_REGISTER(Register, x##N, N, kXRegSize, CPURegister::kRegister);
+REGISTER_CODE_LIST(DEFINE_REGISTERS)
+#undef DEFINE_REGISTERS
+
+INITIALIZE_REGISTER(Register, wcsp, kSPRegInternalCode, kWRegSize,
+                    CPURegister::kRegister);
+INITIALIZE_REGISTER(Register, csp, kSPRegInternalCode, kXRegSize,
+                    CPURegister::kRegister);
+
+#define DEFINE_FPREGISTERS(N)                         \
+  INITIALIZE_REGISTER(FPRegister, s##N, N, kSRegSize, \
+                      CPURegister::kFPRegister);      \
+  INITIALIZE_REGISTER(FPRegister, d##N, N, kDRegSize, CPURegister::kFPRegister);
+REGISTER_CODE_LIST(DEFINE_FPREGISTERS)
+#undef DEFINE_FPREGISTERS
+
+#undef INITIALIZE_REGISTER
+
+// Registers aliases.
+ALIAS_REGISTER(Register, ip0, x16);
+ALIAS_REGISTER(Register, ip1, x17);
+ALIAS_REGISTER(Register, wip0, w16);
+ALIAS_REGISTER(Register, wip1, w17);
+// Root register.
+ALIAS_REGISTER(Register, root, x26);
+ALIAS_REGISTER(Register, rr, x26);
+// Context pointer register.
+ALIAS_REGISTER(Register, cp, x27);
+// We use a register as a JS stack pointer to overcome the restriction on the
+// architectural SP alignment.
+// We chose x28 because it is contiguous with the other specific purpose
+// registers.
+STATIC_ASSERT(kJSSPCode == 28);
+ALIAS_REGISTER(Register, jssp, x28);
+ALIAS_REGISTER(Register, wjssp, w28);
+ALIAS_REGISTER(Register, fp, x29);
+ALIAS_REGISTER(Register, lr, x30);
+ALIAS_REGISTER(Register, xzr, x31);
+ALIAS_REGISTER(Register, wzr, w31);
+
+// Crankshaft double scratch register.
+ALIAS_REGISTER(FPRegister, crankshaft_fp_scratch, d29);
+// Keeps the 0 double value.
+ALIAS_REGISTER(FPRegister, fp_zero, d30);
+// MacroAssembler double scratch register.
+ALIAS_REGISTER(FPRegister, fp_scratch, d31);
+
+#undef ALIAS_REGISTER
+
+// AreAliased returns true if any of the named registers overlap. Arguments set
+// to NoReg are ignored. The system stack pointer may be specified.
+bool AreAliased(const CPURegister& reg1,
+                const CPURegister& reg2,
+                const CPURegister& reg3 = NoReg,
+                const CPURegister& reg4 = NoReg,
+                const CPURegister& reg5 = NoReg,
+                const CPURegister& reg6 = NoReg,
+                const CPURegister& reg7 = NoReg,
+                const CPURegister& reg8 = NoReg);
+
+// AreSameSizeAndType returns true if all of the specified registers have the
+// same size, and are of the same type. The system stack pointer may be
+// specified. Arguments set to NoReg are ignored, as are any subsequent
+// arguments. At least one argument (reg1) must be valid (not NoCPUReg).
+bool AreSameSizeAndType(const CPURegister& reg1,
+                        const CPURegister& reg2,
+                        const CPURegister& reg3 = NoCPUReg,
+                        const CPURegister& reg4 = NoCPUReg,
+                        const CPURegister& reg5 = NoCPUReg,
+                        const CPURegister& reg6 = NoCPUReg,
+                        const CPURegister& reg7 = NoCPUReg,
+                        const CPURegister& reg8 = NoCPUReg);
+
+
+typedef FPRegister DoubleRegister;
+
+
+// -----------------------------------------------------------------------------
+// Lists of registers.
+class CPURegList {
+ public:
+  explicit CPURegList(CPURegister reg1,
+                      CPURegister reg2 = NoCPUReg,
+                      CPURegister reg3 = NoCPUReg,
+                      CPURegister reg4 = NoCPUReg)
+      : list_(reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit()),
+        size_(reg1.SizeInBits()), type_(reg1.type()) {
+    ASSERT(AreSameSizeAndType(reg1, reg2, reg3, reg4));
+    ASSERT(IsValid());
+  }
+
+  CPURegList(CPURegister::RegisterType type, unsigned size, RegList list)
+      : list_(list), size_(size), type_(type) {
+    ASSERT(IsValid());
+  }
+
+  CPURegList(CPURegister::RegisterType type, unsigned size,
+             unsigned first_reg, unsigned last_reg)
+      : size_(size), type_(type) {
+    ASSERT(((type == CPURegister::kRegister) &&
+            (last_reg < kNumberOfRegisters)) ||
+           ((type == CPURegister::kFPRegister) &&
+            (last_reg < kNumberOfFPRegisters)));
+    ASSERT(last_reg >= first_reg);
+    list_ = (1UL << (last_reg + 1)) - 1;
+    list_ &= ~((1UL << first_reg) - 1);
+    ASSERT(IsValid());
+  }
+
+  CPURegister::RegisterType type() const {
+    ASSERT(IsValid());
+    return type_;
+  }
+
+  RegList list() const {
+    ASSERT(IsValid());
+    return list_;
+  }
+
+  // Combine another CPURegList into this one. Registers that already exist in
+  // this list are left unchanged. The type and size of the registers in the
+  // 'other' list must match those in this list.
+  void Combine(const CPURegList& other);
+
+  // Remove every register in the other CPURegList from this one. Registers that
+  // do not exist in this list are ignored. The type and size of the registers
+  // in the 'other' list must match those in this list.
+  void Remove(const CPURegList& other);
+
+  // Variants of Combine and Remove which take a single register.
+  void Combine(const CPURegister& other);
+  void Remove(const CPURegister& other);
+
+  // Variants of Combine and Remove which take a single register by its code;
+  // the type and size of the register is inferred from this list.
+  void Combine(int code);
+  void Remove(int code);
+
+  // Remove all callee-saved registers from the list. This can be useful when
+  // preparing registers for an AAPCS64 function call, for example.
+  void RemoveCalleeSaved();
+
+  CPURegister PopLowestIndex();
+  CPURegister PopHighestIndex();
+
+  // AAPCS64 callee-saved registers.
+  static CPURegList GetCalleeSaved(unsigned size = kXRegSize);
+  static CPURegList GetCalleeSavedFP(unsigned size = kDRegSize);
+
+  // AAPCS64 caller-saved registers. Note that this includes lr.
+  static CPURegList GetCallerSaved(unsigned size = kXRegSize);
+  static CPURegList GetCallerSavedFP(unsigned size = kDRegSize);
+
+  // Registers saved as safepoints.
+  static CPURegList GetSafepointSavedRegisters();
+
+  bool IsEmpty() const {
+    ASSERT(IsValid());
+    return list_ == 0;
+  }
+
+  bool IncludesAliasOf(const CPURegister& other) const {
+    ASSERT(IsValid());
+    return (type_ == other.type()) && (other.Bit() & list_);
+  }
+
+  int Count() const {
+    ASSERT(IsValid());
+    return CountSetBits(list_, kRegListSizeInBits);
+  }
+
+  unsigned RegisterSizeInBits() const {
+    ASSERT(IsValid());
+    return size_;
+  }
+
+  unsigned RegisterSizeInBytes() const {
+    int size_in_bits = RegisterSizeInBits();
+    ASSERT((size_in_bits % kBitsPerByte) == 0);
+    return size_in_bits / kBitsPerByte;
+  }
+
+ private:
+  RegList list_;
+  unsigned size_;
+  CPURegister::RegisterType type_;
+
+  bool IsValid() const {
+    if ((type_ == CPURegister::kRegister) ||
+        (type_ == CPURegister::kFPRegister)) {
+      bool is_valid = true;
+      // Try to create a CPURegister for each element in the list.
+      for (int i = 0; i < kRegListSizeInBits; i++) {
+        if (((list_ >> i) & 1) != 0) {
+          is_valid &= CPURegister::Create(i, size_, type_).IsValid();
+        }
+      }
+      return is_valid;
+    } else if (type_ == CPURegister::kNoRegister) {
+      // The kNoRegister type is valid only for empty lists.
+      // We can't use IsEmpty here because that asserts IsValid().
+      return list_ == 0;
+    } else {
+      return false;
+    }
+  }
+};
+
+
+// AAPCS64 callee-saved registers.
+#define kCalleeSaved CPURegList::GetCalleeSaved()
+#define kCalleeSavedFP CPURegList::GetCalleeSavedFP()
+
+
+// AAPCS64 caller-saved registers. Note that this includes lr.
+#define kCallerSaved CPURegList::GetCallerSaved()
+#define kCallerSavedFP CPURegList::GetCallerSavedFP()
+
+
+// -----------------------------------------------------------------------------
+// Operands.
+const int kSmiShift = kSmiTagSize + kSmiShiftSize;
+const uint64_t kSmiShiftMask = (1UL << kSmiShift) - 1;
+
+// Represents an operand in a machine instruction.
+class Operand {
+  // TODO(all): If necessary, study more in details which methods
+  // TODO(all): should be inlined or not.
+ public:
+  // #<immediate>
+  // where <immediate> is int64_t.
+  // GCC complains about ambiguous aliasing if we don't explicitly declare the
+  // variants.
+  // The simple literal-value wrappers are allowed to be implicit constructors
+  // because Operand is a wrapper class that doesn't normally perform any type
+  // conversion.
+  inline Operand(int64_t immediate,
+      RelocInfo::Mode rmode = RelocInfo::NONE64);    // NOLINT(runtime/explicit)
+  inline Operand(uint64_t immediate,
+      RelocInfo::Mode rmode = RelocInfo::NONE64);    // NOLINT(runtime/explicit)
+  inline Operand(int32_t immediate,
+      RelocInfo::Mode rmode = RelocInfo::NONE32);    // NOLINT(runtime/explicit)
+  inline Operand(uint32_t immediate,
+      RelocInfo::Mode rmode = RelocInfo::NONE32);    // NOLINT(runtime/explicit)
+
+
+  // rm, {<shift> {#<shift_amount>}}
+  // where <shift> is one of {LSL, LSR, ASR, ROR}.
+  //       <shift_amount> is uint6_t.
+  // This is allowed to be an implicit constructor because Operand is
+  // a wrapper class that doesn't normally perform any type conversion.
+  inline Operand(Register reg,
+                 Shift shift = LSL,
+                 unsigned shift_amount = 0);  // NOLINT(runtime/explicit)
+
+  // rm, <extend> {#<shift_amount>}
+  // where <extend> is one of {UXTB, UXTH, UXTW, UXTX, SXTB, SXTH, SXTW, SXTX}.
+  //       <shift_amount> is uint2_t.
+  inline Operand(Register reg,
+                 Extend extend,
+                 unsigned shift_amount = 0);
+
+  inline explicit Operand(Smi* value);
+  explicit Operand(const ExternalReference& f);
+  explicit Operand(Handle<Object> handle);
+
+  inline bool IsImmediate() const;
+  inline bool IsShiftedRegister() const;
+  inline bool IsExtendedRegister() const;
+  inline bool IsZero() const;
+
+  // This returns an LSL shift (<= 4) operand as an equivalent extend operand,
+  // which helps in the encoding of instructions that use the stack pointer.
+  inline Operand ToExtendedRegister() const;
+
+  inline int64_t immediate() const;
+  inline Register reg() const;
+  inline Shift shift() const;
+  inline Extend extend() const;
+  inline unsigned shift_amount() const;
+
+  // Relocation information.
+  RelocInfo::Mode rmode() const { return rmode_; }
+  void set_rmode(RelocInfo::Mode rmode) { rmode_ = rmode; }
+  bool NeedsRelocation() const;
+
+  // Helpers
+  inline static Operand UntagSmi(Register smi);
+  inline static Operand UntagSmiAndScale(Register smi, int scale);
+
+ private:
+  int64_t immediate_;
+  Register reg_;
+  Shift shift_;
+  Extend extend_;
+  unsigned shift_amount_;
+  RelocInfo::Mode rmode_;
+};
+
+
+// MemOperand represents a memory operand in a load or store instruction.
+class MemOperand {
+ public:
+  inline explicit MemOperand(Register base,
+                             ptrdiff_t offset = 0,
+                             AddrMode addrmode = Offset);
+  inline explicit MemOperand(Register base,
+                             Register regoffset,
+                             Shift shift = LSL,
+                             unsigned shift_amount = 0);
+  inline explicit MemOperand(Register base,
+                             Register regoffset,
+                             Extend extend,
+                             unsigned shift_amount = 0);
+  inline explicit MemOperand(Register base,
+                             const Operand& offset,
+                             AddrMode addrmode = Offset);
+
+  const Register& base() const { return base_; }
+  const Register& regoffset() const { return regoffset_; }
+  ptrdiff_t offset() const { return offset_; }
+  AddrMode addrmode() const { return addrmode_; }
+  Shift shift() const { return shift_; }
+  Extend extend() const { return extend_; }
+  unsigned shift_amount() const { return shift_amount_; }
+  inline bool IsImmediateOffset() const;
+  inline bool IsRegisterOffset() const;
+  inline bool IsPreIndex() const;
+  inline bool IsPostIndex() const;
+
+  // For offset modes, return the offset as an Operand. This helper cannot
+  // handle indexed modes.
+  inline Operand OffsetAsOperand() const;
+
+ private:
+  Register base_;
+  Register regoffset_;
+  ptrdiff_t offset_;
+  AddrMode addrmode_;
+  Shift shift_;
+  Extend extend_;
+  unsigned shift_amount_;
+};
+
+
+// -----------------------------------------------------------------------------
+// Assembler.
+
+class Assembler : public AssemblerBase {
+ public:
+  // Create an assembler. Instructions and relocation information are emitted
+  // into a buffer, with the instructions starting from the beginning and the
+  // relocation information starting from the end of the buffer. See CodeDesc
+  // for a detailed comment on the layout (globals.h).
+  //
+  // If the provided buffer is NULL, the assembler allocates and grows its own
+  // buffer, and buffer_size determines the initial buffer size. The buffer is
+  // owned by the assembler and deallocated upon destruction of the assembler.
+  //
+  // If the provided buffer is not NULL, the assembler uses the provided buffer
+  // for code generation and assumes its size to be buffer_size. If the buffer
+  // is too small, a fatal error occurs. No deallocation of the buffer is done
+  // upon destruction of the assembler.
+  Assembler(Isolate* arg_isolate, void* buffer, int buffer_size);
+
+  virtual ~Assembler();
+
+  // System functions ---------------------------------------------------------
+  // Start generating code from the beginning of the buffer, discarding any code
+  // and data that has already been emitted into the buffer.
+  //
+  // In order to avoid any accidental transfer of state, Reset ASSERTs that the
+  // constant pool is not blocked.
+  void Reset();
+
+  // GetCode emits any pending (non-emitted) code and fills the descriptor
+  // desc. GetCode() is idempotent; it returns the same result if no other
+  // Assembler functions are invoked in between GetCode() calls.
+  //
+  // The descriptor (desc) can be NULL. In that case, the code is finalized as
+  // usual, but the descriptor is not populated.
+  void GetCode(CodeDesc* desc);
+
+  // Insert the smallest number of nop instructions
+  // possible to align the pc offset to a multiple
+  // of m. m must be a power of 2 (>= 4).
+  void Align(int m);
+
+  // Label --------------------------------------------------------------------
+  // Bind a label to the current pc. Note that labels can only be bound once,
+  // and if labels are linked to other instructions, they _must_ be bound
+  // before they go out of scope.
+  void bind(Label* label);
+
+
+  // RelocInfo and constant pool ----------------------------------------------
+
+  // Record relocation information for current pc_.
+  void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
+
+  // Return the address in the constant pool of the code target address used by
+  // the branch/call instruction at pc.
+  inline static Address target_pointer_address_at(Address pc);
+
+  // Read/Modify the code target address in the branch/call instruction at pc.
+  inline static Address target_address_at(Address pc);
+  inline static void set_target_address_at(Address pc, Address target);
+
+  // Return the code target address at a call site from the return address of
+  // that call in the instruction stream.
+  inline static Address target_address_from_return_address(Address pc);
+
+  // Given the address of the beginning of a call, return the address in the
+  // instruction stream that call will return from.
+  inline static Address return_address_from_call_start(Address pc);
+
+  // This sets the branch destination (which is in the constant pool on ARM).
+  // This is for calls and branches within generated code.
+  inline static void deserialization_set_special_target_at(
+      Address constant_pool_entry, Address target);
+
+  // All addresses in the constant pool are the same size as pointers.
+  static const int kSpecialTargetSize = kPointerSize;
+
+  // The sizes of the call sequences emitted by MacroAssembler::Call.
+  // Wherever possible, use MacroAssembler::CallSize instead of these constants,
+  // as it will choose the correct value for a given relocation mode.
+  //
+  // 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
+  static const int kCallSizeWithoutRelocation = 5 * kInstructionSize;
+  static const int kCallSizeWithRelocation = 2 * kInstructionSize;
+
+  // Size of the generated code in bytes
+  uint64_t SizeOfGeneratedCode() const {
+    ASSERT((pc_ >= buffer_) && (pc_ < (buffer_ + buffer_size_)));
+    return pc_ - buffer_;
+  }
+
+  // Return the code size generated from label to the current position.
+  uint64_t SizeOfCodeGeneratedSince(const Label* label) {
+    ASSERT(label->is_bound());
+    ASSERT(pc_offset() >= label->pos());
+    ASSERT(pc_offset() < buffer_size_);
+    return pc_offset() - label->pos();
+  }
+
+  // Check the size of the code generated since the given label. This function
+  // is used primarily to work around comparisons between signed and unsigned
+  // quantities, since V8 uses both.
+  // TODO(jbramley): Work out what sign to use for these things and if possible,
+  // change things to be consistent.
+  void AssertSizeOfCodeGeneratedSince(const Label* label, ptrdiff_t size) {
+    ASSERT(size >= 0);
+    ASSERT(static_cast<uint64_t>(size) == SizeOfCodeGeneratedSince(label));
+  }
+
+  // Return the number of instructions generated from label to the
+  // current position.
+  int InstructionsGeneratedSince(const Label* label) {
+    return SizeOfCodeGeneratedSince(label) / kInstructionSize;
+  }
+
+  // TODO(all): Initialize these constants related with code patching.
+  // TODO(all): Set to -1 to hopefully crash if mistakenly used.
+
+  // Number of instructions generated for the return sequence in
+  // FullCodeGenerator::EmitReturnSequence.
+  static const int kJSRetSequenceInstructions = 7;
+  // Distance between start of patched return sequence and the emitted address
+  // to jump to.
+  static const int kPatchReturnSequenceAddressOffset =  0;
+  static const int kPatchDebugBreakSlotAddressOffset =  0;
+
+  // Number of instructions necessary to be able to later patch it to a call.
+  // See Debug::GenerateSlot() and BreakLocationIterator::SetDebugBreakAtSlot().
+  static const int kDebugBreakSlotInstructions = 4;
+  static const int kDebugBreakSlotLength =
+    kDebugBreakSlotInstructions * kInstructionSize;
+
+  static const int kPatchDebugBreakSlotReturnOffset = 2 * kInstructionSize;
+
+  // Prevent contant pool emission until EndBlockConstPool is called.
+  // Call to this function can be nested but must be followed by an equal
+  // number of call to EndBlockConstpool.
+  void StartBlockConstPool();
+
+  // Resume constant pool emission. Need to be called as many time as
+  // StartBlockConstPool to have an effect.
+  void EndBlockConstPool();
+
+  bool is_const_pool_blocked() const;
+  static bool IsConstantPoolAt(Instruction* instr);
+  static int ConstantPoolSizeAt(Instruction* instr);
+  // See Assembler::CheckConstPool for more info.
+  void ConstantPoolMarker(uint32_t size);
+  void ConstantPoolGuard();
+
+
+  // Debugging ----------------------------------------------------------------
+  PositionsRecorder* positions_recorder() { return &positions_recorder_; }
+  void RecordComment(const char* msg);
+  int buffer_space() const;
+
+  // Mark address of the ExitJSFrame code.
+  void RecordJSReturn();
+
+  // Mark address of a debug break slot.
+  void RecordDebugBreakSlot();
+
+  // Record the emission of a constant pool.
+  //
+  // The emission of constant pool depends on the size of the code generated and
+  // the number of RelocInfo recorded.
+  // The Debug mechanism needs to map code offsets between two versions of a
+  // function, compiled with and without debugger support (see for example
+  // Debug::PrepareForBreakPoints()).
+  // Compiling functions with debugger support generates additional code
+  // (Debug::GenerateSlot()). This may affect the emission of the constant
+  // pools and cause the version of the code with debugger support to have
+  // constant pools generated in different places.
+  // Recording the position and size of emitted constant pools allows to
+  // correctly compute the offset mappings between the different versions of a
+  // function in all situations.
+  //
+  // The parameter indicates the size of the constant pool (in bytes), including
+  // the marker and branch over the data.
+  void RecordConstPool(int size);
+
+
+  // Instruction set functions ------------------------------------------------
+
+  // Branch / Jump instructions.
+  // For branches offsets are scaled, i.e. they in instrcutions not in bytes.
+  // Branch to register.
+  void br(const Register& xn);
+
+  // Branch-link to register.
+  void blr(const Register& xn);
+
+  // Branch to register with return hint.
+  void ret(const Register& xn = lr);
+
+  // Unconditional branch to label.
+  void b(Label* label);
+
+  // Conditional branch to label.
+  void b(Label* label, Condition cond);
+
+  // Unconditional branch to PC offset.
+  void b(int imm26);
+
+  // Conditional branch to PC offset.
+  void b(int imm19, Condition cond);
+
+  // Branch-link to label / pc offset.
+  void bl(Label* label);
+  void bl(int imm26);
+
+  // Compare and branch to label / pc offset if zero.
+  void cbz(const Register& rt, Label* label);
+  void cbz(const Register& rt, int imm19);
+
+  // Compare and branch to label / pc offset if not zero.
+  void cbnz(const Register& rt, Label* label);
+  void cbnz(const Register& rt, int imm19);
+
+  // Test bit and branch to label / pc offset if zero.
+  void tbz(const Register& rt, unsigned bit_pos, Label* label);
+  void tbz(const Register& rt, unsigned bit_pos, int imm14);
+
+  // Test bit and branch to label / pc offset if not zero.
+  void tbnz(const Register& rt, unsigned bit_pos, Label* label);
+  void tbnz(const Register& rt, unsigned bit_pos, int imm14);
+
+  // Address calculation instructions.
+  // Calculate a PC-relative address. Unlike for branches the offset in adr is
+  // unscaled (i.e. the result can be unaligned).
+  void adr(const Register& rd, Label* label);
+  void adr(const Register& rd, int imm21);
+
+  // Data Processing instructions.
+  // Add.
+  void add(const Register& rd,
+           const Register& rn,
+           const Operand& operand);
+
+  // Add and update status flags.
+  void adds(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Compare negative.
+  void cmn(const Register& rn, const Operand& operand);
+
+  // Subtract.
+  void sub(const Register& rd,
+           const Register& rn,
+           const Operand& operand);
+
+  // Subtract and update status flags.
+  void subs(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Compare.
+  void cmp(const Register& rn, const Operand& operand);
+
+  // Negate.
+  void neg(const Register& rd,
+           const Operand& operand);
+
+  // Negate and update status flags.
+  void negs(const Register& rd,
+            const Operand& operand);
+
+  // Add with carry bit.
+  void adc(const Register& rd,
+           const Register& rn,
+           const Operand& operand);
+
+  // Add with carry bit and update status flags.
+  void adcs(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Subtract with carry bit.
+  void sbc(const Register& rd,
+           const Register& rn,
+           const Operand& operand);
+
+  // Subtract with carry bit and update status flags.
+  void sbcs(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Negate with carry bit.
+  void ngc(const Register& rd,
+           const Operand& operand);
+
+  // Negate with carry bit and update status flags.
+  void ngcs(const Register& rd,
+            const Operand& operand);
+
+  // Logical instructions.
+  // Bitwise and (A & B).
+  void and_(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Bitwise and (A & B) and update status flags.
+  void ands(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Bit test, and set flags.
+  void tst(const Register& rn, const Operand& operand);
+
+  // Bit clear (A & ~B).
+  void bic(const Register& rd,
+           const Register& rn,
+           const Operand& operand);
+
+  // Bit clear (A & ~B) and update status flags.
+  void bics(const Register& rd,
+            const Register& rn,
+            const Operand& operand);
+
+  // Bitwise or (A | B).
+  void orr(const Register& rd, const Register& rn, const Operand& operand);
+
+  // Bitwise nor (A | ~B).
+  void orn(const Register& rd, const Register& rn, const Operand& operand);
+
+  // Bitwise eor/xor (A ^ B).
+  void eor(const Register& rd, const Register& rn, const Operand& operand);
+
+  // Bitwise enor/xnor (A ^ ~B).
+  void eon(const Register& rd, const Register& rn, const Operand& operand);
+
+  // Logical shift left variable.
+  void lslv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Logical shift right variable.
+  void lsrv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Arithmetic shift right variable.
+  void asrv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Rotate right variable.
+  void rorv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Bitfield instructions.
+  // Bitfield move.
+  void bfm(const Register& rd,
+           const Register& rn,
+           unsigned immr,
+           unsigned imms);
+
+  // Signed bitfield move.
+  void sbfm(const Register& rd,
+            const Register& rn,
+            unsigned immr,
+            unsigned imms);
+
+  // Unsigned bitfield move.
+  void ubfm(const Register& rd,
+            const Register& rn,
+            unsigned immr,
+            unsigned imms);
+
+  // Bfm aliases.
+  // Bitfield insert.
+  void bfi(const Register& rd,
+           const Register& rn,
+           unsigned lsb,
+           unsigned width) {
+    ASSERT(width >= 1);
+    ASSERT(lsb + width <= rn.SizeInBits());
+    bfm(rd, rn, (rd.SizeInBits() - lsb) & (rd.SizeInBits() - 1), width - 1);
+  }
+
+  // Bitfield extract and insert low.
+  void bfxil(const Register& rd,
+             const Register& rn,
+             unsigned lsb,
+             unsigned width) {
+    ASSERT(width >= 1);
+    ASSERT(lsb + width <= rn.SizeInBits());
+    bfm(rd, rn, lsb, lsb + width - 1);
+  }
+
+  // Sbfm aliases.
+  // Arithmetic shift right.
+  void asr(const Register& rd, const Register& rn, unsigned shift) {
+    ASSERT(shift < rd.SizeInBits());
+    sbfm(rd, rn, shift, rd.SizeInBits() - 1);
+  }
+
+  // Signed bitfield insert in zero.
+  void sbfiz(const Register& rd,
+             const Register& rn,
+             unsigned lsb,
+             unsigned width) {
+    ASSERT(width >= 1);
+    ASSERT(lsb + width <= rn.SizeInBits());
+    sbfm(rd, rn, (rd.SizeInBits() - lsb) & (rd.SizeInBits() - 1), width - 1);
+  }
+
+  // Signed bitfield extract.
+  void sbfx(const Register& rd,
+            const Register& rn,
+            unsigned lsb,
+            unsigned width) {
+    ASSERT(width >= 1);
+    ASSERT(lsb + width <= rn.SizeInBits());
+    sbfm(rd, rn, lsb, lsb + width - 1);
+  }
+
+  // Signed extend byte.
+  void sxtb(const Register& rd, const Register& rn) {
+    sbfm(rd, rn, 0, 7);
+  }
+
+  // Signed extend halfword.
+  void sxth(const Register& rd, const Register& rn) {
+    sbfm(rd, rn, 0, 15);
+  }
+
+  // Signed extend word.
+  void sxtw(const Register& rd, const Register& rn) {
+    sbfm(rd, rn, 0, 31);
+  }
+
+  // Ubfm aliases.
+  // Logical shift left.
+  void lsl(const Register& rd, const Register& rn, unsigned shift) {
+    unsigned reg_size = rd.SizeInBits();
+    ASSERT(shift < reg_size);
+    ubfm(rd, rn, (reg_size - shift) % reg_size, reg_size - shift - 1);
+  }
+
+  // Logical shift right.
+  void lsr(const Register& rd, const Register& rn, unsigned shift) {
+    ASSERT(shift < rd.SizeInBits());
+    ubfm(rd, rn, shift, rd.SizeInBits() - 1);
+  }
+
+  // Unsigned bitfield insert in zero.
+  void ubfiz(const Register& rd,
+             const Register& rn,
+             unsigned lsb,
+             unsigned width) {
+    ASSERT(width >= 1);
+    ASSERT(lsb + width <= rn.SizeInBits());
+    ubfm(rd, rn, (rd.SizeInBits() - lsb) & (rd.SizeInBits() - 1), width - 1);
+  }
+
+  // Unsigned bitfield extract.
+  void ubfx(const Register& rd,
+            const Register& rn,
+            unsigned lsb,
+            unsigned width) {
+    ASSERT(width >= 1);
+    ASSERT(lsb + width <= rn.SizeInBits());
+    ubfm(rd, rn, lsb, lsb + width - 1);
+  }
+
+  // Unsigned extend byte.
+  void uxtb(const Register& rd, const Register& rn) {
+    ubfm(rd, rn, 0, 7);
+  }
+
+  // Unsigned extend halfword.
+  void uxth(const Register& rd, const Register& rn) {
+    ubfm(rd, rn, 0, 15);
+  }
+
+  // Unsigned extend word.
+  void uxtw(const Register& rd, const Register& rn) {
+    ubfm(rd, rn, 0, 31);
+  }
+
+  // Extract.
+  void extr(const Register& rd,
+            const Register& rn,
+            const Register& rm,
+            unsigned lsb);
+
+  // Conditional select: rd = cond ? rn : rm.
+  void csel(const Register& rd,
+            const Register& rn,
+            const Register& rm,
+            Condition cond);
+
+  // Conditional select increment: rd = cond ? rn : rm + 1.
+  void csinc(const Register& rd,
+             const Register& rn,
+             const Register& rm,
+             Condition cond);
+
+  // Conditional select inversion: rd = cond ? rn : ~rm.
+  void csinv(const Register& rd,
+             const Register& rn,
+             const Register& rm,
+             Condition cond);
+
+  // Conditional select negation: rd = cond ? rn : -rm.
+  void csneg(const Register& rd,
+             const Register& rn,
+             const Register& rm,
+             Condition cond);
+
+  // Conditional set: rd = cond ? 1 : 0.
+  void cset(const Register& rd, Condition cond);
+
+  // Conditional set minus: rd = cond ? -1 : 0.
+  void csetm(const Register& rd, Condition cond);
+
+  // Conditional increment: rd = cond ? rn + 1 : rn.
+  void cinc(const Register& rd, const Register& rn, Condition cond);
+
+  // Conditional invert: rd = cond ? ~rn : rn.
+  void cinv(const Register& rd, const Register& rn, Condition cond);
+
+  // Conditional negate: rd = cond ? -rn : rn.
+  void cneg(const Register& rd, const Register& rn, Condition cond);
+
+  // Extr aliases.
+  void ror(const Register& rd, const Register& rs, unsigned shift) {
+    extr(rd, rs, rs, shift);
+  }
+
+  // Conditional comparison.
+  // Conditional compare negative.
+  void ccmn(const Register& rn,
+            const Operand& operand,
+            StatusFlags nzcv,
+            Condition cond);
+
+  // Conditional compare.
+  void ccmp(const Register& rn,
+            const Operand& operand,
+            StatusFlags nzcv,
+            Condition cond);
+
+  // Multiplication.
+  // 32 x 32 -> 32-bit and 64 x 64 -> 64-bit multiply.
+  void mul(const Register& rd, const Register& rn, const Register& rm);
+
+  // 32 + 32 x 32 -> 32-bit and 64 + 64 x 64 -> 64-bit multiply accumulate.
+  void madd(const Register& rd,
+            const Register& rn,
+            const Register& rm,
+            const Register& ra);
+
+  // -(32 x 32) -> 32-bit and -(64 x 64) -> 64-bit multiply.
+  void mneg(const Register& rd, const Register& rn, const Register& rm);
+
+  // 32 - 32 x 32 -> 32-bit and 64 - 64 x 64 -> 64-bit multiply subtract.
+  void msub(const Register& rd,
+            const Register& rn,
+            const Register& rm,
+            const Register& ra);
+
+  // 32 x 32 -> 64-bit multiply.
+  void smull(const Register& rd, const Register& rn, const Register& rm);
+
+  // Xd = bits<127:64> of Xn * Xm.
+  void smulh(const Register& rd, const Register& rn, const Register& rm);
+
+  // Signed 32 x 32 -> 64-bit multiply and accumulate.
+  void smaddl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Unsigned 32 x 32 -> 64-bit multiply and accumulate.
+  void umaddl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Signed 32 x 32 -> 64-bit multiply and subtract.
+  void smsubl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Unsigned 32 x 32 -> 64-bit multiply and subtract.
+  void umsubl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Signed integer divide.
+  void sdiv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Unsigned integer divide.
+  void udiv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Bit count, bit reverse and endian reverse.
+  void rbit(const Register& rd, const Register& rn);
+  void rev16(const Register& rd, const Register& rn);
+  void rev32(const Register& rd, const Register& rn);
+  void rev(const Register& rd, const Register& rn);
+  void clz(const Register& rd, const Register& rn);
+  void cls(const Register& rd, const Register& rn);
+
+  // Memory instructions.
+
+  // Load literal from pc + offset_from_pc.
+  void LoadLiteral(const CPURegister& rt, int offset_from_pc);
+
+  // Load integer or FP register.
+  void ldr(const CPURegister& rt, const MemOperand& src);
+
+  // Store integer or FP register.
+  void str(const CPURegister& rt, const MemOperand& dst);
+
+  // Load word with sign extension.
+  void ldrsw(const Register& rt, const MemOperand& src);
+
+  // Load byte.
+  void ldrb(const Register& rt, const MemOperand& src);
+
+  // Store byte.
+  void strb(const Register& rt, const MemOperand& dst);
+
+  // Load byte with sign extension.
+  void ldrsb(const Register& rt, const MemOperand& src);
+
+  // Load half-word.
+  void ldrh(const Register& rt, const MemOperand& src);
+
+  // Store half-word.
+  void strh(const Register& rt, const MemOperand& dst);
+
+  // Load half-word with sign extension.
+  void ldrsh(const Register& rt, const MemOperand& src);
+
+  // Load integer or FP register pair.
+  void ldp(const CPURegister& rt, const CPURegister& rt2,
+           const MemOperand& src);
+
+  // Store integer or FP register pair.
+  void stp(const CPURegister& rt, const CPURegister& rt2,
+           const MemOperand& dst);
+
+  // Load word pair with sign extension.
+  void ldpsw(const Register& rt, const Register& rt2, const MemOperand& src);
+
+  // Load integer or FP register pair, non-temporal.
+  void ldnp(const CPURegister& rt, const CPURegister& rt2,
+            const MemOperand& src);
+
+  // Store integer or FP register pair, non-temporal.
+  void stnp(const CPURegister& rt, const CPURegister& rt2,
+            const MemOperand& dst);
+
+  // Load literal to register.
+  void ldr(const Register& rt, uint64_t imm);
+
+  // Load literal to FP register.
+  void ldr(const FPRegister& ft, double imm);
+
+  // Move instructions. The default shift of -1 indicates that the move
+  // instruction will calculate an appropriate 16-bit immediate and left shift
+  // that is equal to the 64-bit immediate argument. If an explicit left shift
+  // is specified (0, 16, 32 or 48), the immediate must be a 16-bit value.
+  //
+  // For movk, an explicit shift can be used to indicate which half word should
+  // be overwritten, eg. movk(x0, 0, 0) will overwrite the least-significant
+  // half word with zero, whereas movk(x0, 0, 48) will overwrite the
+  // most-significant.
+
+  // Move and keep.
+  void movk(const Register& rd, uint64_t imm, int shift = -1) {
+    MoveWide(rd, imm, shift, MOVK);
+  }
+
+  // Move with non-zero.
+  void movn(const Register& rd, uint64_t imm, int shift = -1) {
+    MoveWide(rd, imm, shift, MOVN);
+  }
+
+  // Move with zero.
+  void movz(const Register& rd, uint64_t imm, int shift = -1) {
+    MoveWide(rd, imm, shift, MOVZ);
+  }
+
+  // Misc instructions.
+  // Monitor debug-mode breakpoint.
+  void brk(int code);
+
+  // Halting debug-mode breakpoint.
+  void hlt(int code);
+
+  // Move register to register.
+  void mov(const Register& rd, const Register& rn);
+
+  // Move NOT(operand) to register.
+  void mvn(const Register& rd, const Operand& operand);
+
+  // System instructions.
+  // Move to register from system register.
+  void mrs(const Register& rt, SystemRegister sysreg);
+
+  // Move from register to system register.
+  void msr(SystemRegister sysreg, const Register& rt);
+
+  // System hint.
+  void hint(SystemHint code);
+
+  // Data memory barrier
+  void dmb(BarrierDomain domain, BarrierType type);
+
+  // Data synchronization barrier
+  void dsb(BarrierDomain domain, BarrierType type);
+
+  // Instruction synchronization barrier
+  void isb();
+
+  // Alias for system instructions.
+  void nop() { hint(NOP); }
+
+  // Different nop operations are used by the code generator to detect certain
+  // states of the generated code.
+  enum NopMarkerTypes {
+    DEBUG_BREAK_NOP,
+    INTERRUPT_CODE_NOP,
+    FIRST_NOP_MARKER = DEBUG_BREAK_NOP,
+    LAST_NOP_MARKER = INTERRUPT_CODE_NOP
+  };
+
+  void nop(NopMarkerTypes n) {
+    ASSERT((FIRST_NOP_MARKER <= n) && (n <= LAST_NOP_MARKER));
+    mov(Register::XRegFromCode(n), Register::XRegFromCode(n));
+  }
+
+  // FP instructions.
+  // Move immediate to FP register.
+  void fmov(FPRegister fd, double imm);
+
+  // Move FP register to register.
+  void fmov(Register rd, FPRegister fn);
+
+  // Move register to FP register.
+  void fmov(FPRegister fd, Register rn);
+
+  // Move FP register to FP register.
+  void fmov(FPRegister fd, FPRegister fn);
+
+  // FP add.
+  void fadd(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP subtract.
+  void fsub(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP multiply.
+  void fmul(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP fused multiply and add.
+  void fmadd(const FPRegister& fd,
+             const FPRegister& fn,
+             const FPRegister& fm,
+             const FPRegister& fa);
+
+  // FP fused multiply and subtract.
+  void fmsub(const FPRegister& fd,
+             const FPRegister& fn,
+             const FPRegister& fm,
+             const FPRegister& fa);
+
+  // FP fused multiply, add and negate.
+  void fnmadd(const FPRegister& fd,
+              const FPRegister& fn,
+              const FPRegister& fm,
+              const FPRegister& fa);
+
+  // FP fused multiply, subtract and negate.
+  void fnmsub(const FPRegister& fd,
+              const FPRegister& fn,
+              const FPRegister& fm,
+              const FPRegister& fa);
+
+  // FP divide.
+  void fdiv(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP maximum.
+  void fmax(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP minimum.
+  void fmin(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP maximum.
+  void fmaxnm(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP minimum.
+  void fminnm(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP absolute.
+  void fabs(const FPRegister& fd, const FPRegister& fn);
+
+  // FP negate.
+  void fneg(const FPRegister& fd, const FPRegister& fn);
+
+  // FP square root.
+  void fsqrt(const FPRegister& fd, const FPRegister& fn);
+
+  // FP round to integer (nearest with ties to away).
+  void frinta(const FPRegister& fd, const FPRegister& fn);
+
+  // FP round to integer (nearest with ties to even).
+  void frintn(const FPRegister& fd, const FPRegister& fn);
+
+  // FP round to integer (towards zero.)
+  void frintz(const FPRegister& fd, const FPRegister& fn);
+
+  // FP compare registers.
+  void fcmp(const FPRegister& fn, const FPRegister& fm);
+
+  // FP compare immediate.
+  void fcmp(const FPRegister& fn, double value);
+
+  // FP conditional compare.
+  void fccmp(const FPRegister& fn,
+             const FPRegister& fm,
+             StatusFlags nzcv,
+             Condition cond);
+
+  // FP conditional select.
+  void fcsel(const FPRegister& fd,
+             const FPRegister& fn,
+             const FPRegister& fm,
+             Condition cond);
+
+  // Common FP Convert function
+  void FPConvertToInt(const Register& rd,
+                      const FPRegister& fn,
+                      FPIntegerConvertOp op);
+
+  // FP convert between single and double precision.
+  void fcvt(const FPRegister& fd, const FPRegister& fn);
+
+  // Convert FP to unsigned integer (nearest with ties to away).
+  void fcvtau(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to signed integer (nearest with ties to away).
+  void fcvtas(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to unsigned integer (round towards -infinity).
+  void fcvtmu(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to signed integer (round towards -infinity).
+  void fcvtms(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to unsigned integer (nearest with ties to even).
+  void fcvtnu(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to signed integer (nearest with ties to even).
+  void fcvtns(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to unsigned integer (round towards zero).
+  void fcvtzu(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to signed integer (rounf towards zero).
+  void fcvtzs(const Register& rd, const FPRegister& fn);
+
+  // Convert signed integer or fixed point to FP.
+  void scvtf(const FPRegister& fd, const Register& rn, unsigned fbits = 0);
+
+  // Convert unsigned integer or fixed point to FP.
+  void ucvtf(const FPRegister& fd, const Register& rn, unsigned fbits = 0);
+
+  // Instruction functions used only for test, debug, and patching.
+  // Emit raw instructions in the instruction stream.
+  void dci(Instr raw_inst) { Emit(raw_inst); }
+
+  // Emit 8 bits of data in the instruction stream.
+  void dc8(uint8_t data) { EmitData(&data, sizeof(data)); }
+
+  // Emit 32 bits of data in the instruction stream.
+  void dc32(uint32_t data) { EmitData(&data, sizeof(data)); }
+
+  // Emit 64 bits of data in the instruction stream.
+  void dc64(uint64_t data) { EmitData(&data, sizeof(data)); }
+
+  // Copy a string into the instruction stream, including the terminating NULL
+  // character. The instruction pointer (pc_) is then aligned correctly for
+  // subsequent instructions.
+  void EmitStringData(const char * string) {
+    size_t len = strlen(string) + 1;
+    ASSERT(RoundUp(len, kInstructionSize) <= static_cast<size_t>(kGap));
+    EmitData(string, len);
+    // Pad with NULL characters until pc_ is aligned.
+    const char pad[] = {'\0', '\0', '\0', '\0'};
+    STATIC_ASSERT(sizeof(pad) == kInstructionSize);
+    byte* next_pc = AlignUp(pc_, kInstructionSize);
+    EmitData(&pad, next_pc - pc_);
+  }
+
+  // Pseudo-instructions ------------------------------------------------------
+
+  // Parameters are described in a64/instructions-a64.h.
+  void debug(const char* message, uint32_t code, Instr params = BREAK);
+
+  // Required by V8.
+  void dd(uint32_t data) { dc32(data); }
+  void db(uint8_t data) { dc8(data); }
+
+  // Code generation helpers --------------------------------------------------
+
+  unsigned num_pending_reloc_info() const { return num_pending_reloc_info_; }
+
+  Instruction* InstructionAt(int offset) const {
+    return reinterpret_cast<Instruction*>(buffer_ + offset);
+  }
+
+  // Register encoding.
+  static Instr Rd(CPURegister rd) {
+    ASSERT(rd.code() != kSPRegInternalCode);
+    return rd.code() << Rd_offset;
+  }
+
+  static Instr Rn(CPURegister rn) {
+    ASSERT(rn.code() != kSPRegInternalCode);
+    return rn.code() << Rn_offset;
+  }
+
+  static Instr Rm(CPURegister rm) {
+    ASSERT(rm.code() != kSPRegInternalCode);
+    return rm.code() << Rm_offset;
+  }
+
+  static Instr Ra(CPURegister ra) {
+    ASSERT(ra.code() != kSPRegInternalCode);
+    return ra.code() << Ra_offset;
+  }
+
+  static Instr Rt(CPURegister rt) {
+    ASSERT(rt.code() != kSPRegInternalCode);
+    return rt.code() << Rt_offset;
+  }
+
+  static Instr Rt2(CPURegister rt2) {
+    ASSERT(rt2.code() != kSPRegInternalCode);
+    return rt2.code() << Rt2_offset;
+  }
+
+  // These encoding functions allow the stack pointer to be encoded, and
+  // disallow the zero register.
+  static Instr RdSP(Register rd) {
+    ASSERT(!rd.IsZero());
+    return (rd.code() & kRegCodeMask) << Rd_offset;
+  }
+
+  static Instr RnSP(Register rn) {
+    ASSERT(!rn.IsZero());
+    return (rn.code() & kRegCodeMask) << Rn_offset;
+  }
+
+  // Flags encoding.
+  inline static Instr Flags(FlagsUpdate S);
+  inline static Instr Cond(Condition cond);
+
+  // PC-relative address encoding.
+  inline static Instr ImmPCRelAddress(int imm21);
+
+  // Branch encoding.
+  inline static Instr ImmUncondBranch(int imm26);
+  inline static Instr ImmCondBranch(int imm19);
+  inline static Instr ImmCmpBranch(int imm19);
+  inline static Instr ImmTestBranch(int imm14);
+  inline static Instr ImmTestBranchBit(unsigned bit_pos);
+
+  // Data Processing encoding.
+  inline static Instr SF(Register rd);
+  inline static Instr ImmAddSub(int64_t imm);
+  inline static Instr ImmS(unsigned imms, unsigned reg_size);
+  inline static Instr ImmR(unsigned immr, unsigned reg_size);
+  inline static Instr ImmSetBits(unsigned imms, unsigned reg_size);
+  inline static Instr ImmRotate(unsigned immr, unsigned reg_size);
+  inline static Instr ImmLLiteral(int imm19);
+  inline static Instr BitN(unsigned bitn, unsigned reg_size);
+  inline static Instr ShiftDP(Shift shift);
+  inline static Instr ImmDPShift(unsigned amount);
+  inline static Instr ExtendMode(Extend extend);
+  inline static Instr ImmExtendShift(unsigned left_shift);
+  inline static Instr ImmCondCmp(unsigned imm);
+  inline static Instr Nzcv(StatusFlags nzcv);
+
+  // MemOperand offset encoding.
+  inline static Instr ImmLSUnsigned(int imm12);
+  inline static Instr ImmLS(int imm9);
+  inline static Instr ImmLSPair(int imm7, LSDataSize size);
+  inline static Instr ImmShiftLS(unsigned shift_amount);
+  inline static Instr ImmException(int imm16);
+  inline static Instr ImmSystemRegister(int imm15);
+  inline static Instr ImmHint(int imm7);
+  inline static Instr ImmBarrierDomain(int imm2);
+  inline static Instr ImmBarrierType(int imm2);
+  inline static LSDataSize CalcLSDataSize(LoadStoreOp op);
+
+  // Move immediates encoding.
+  inline static Instr ImmMoveWide(uint64_t imm);
+  inline static Instr ShiftMoveWide(int64_t shift);
+
+  // FP Immediates.
+  static Instr ImmFP32(float imm);
+  static Instr ImmFP64(double imm);
+  inline static Instr FPScale(unsigned scale);
+
+  // FP register type.
+  inline static Instr FPType(FPRegister fd);
+
+  // Class for scoping postponing the constant pool generation.
+  class BlockConstPoolScope {
+   public:
+    explicit BlockConstPoolScope(Assembler* assem) : assem_(assem) {
+      assem_->StartBlockConstPool();
+    }
+    ~BlockConstPoolScope() {
+      assem_->EndBlockConstPool();
+    }
+
+   private:
+    Assembler* assem_;
+
+    DISALLOW_IMPLICIT_CONSTRUCTORS(BlockConstPoolScope);
+  };
+
+  // Check if is time to emit a constant pool.
+  void CheckConstPool(bool force_emit, bool require_jump);
+
+  // Available for constrained code generation scopes. Prefer
+  // MacroAssembler::Mov() when possible.
+  inline void LoadRelocated(const CPURegister& rt, const Operand& operand);
+
+ protected:
+  inline const Register& AppropriateZeroRegFor(const CPURegister& reg) const;
+
+  void LoadStore(const CPURegister& rt,
+                 const MemOperand& addr,
+                 LoadStoreOp op);
+  static bool IsImmLSUnscaled(ptrdiff_t offset);
+  static bool IsImmLSScaled(ptrdiff_t offset, LSDataSize size);
+
+  void Logical(const Register& rd,
+               const Register& rn,
+               const Operand& operand,
+               LogicalOp op);
+  void LogicalImmediate(const Register& rd,
+                        const Register& rn,
+                        unsigned n,
+                        unsigned imm_s,
+                        unsigned imm_r,
+                        LogicalOp op);
+  static bool IsImmLogical(uint64_t value,
+                           unsigned width,
+                           unsigned* n,
+                           unsigned* imm_s,
+                           unsigned* imm_r);
+
+  void ConditionalCompare(const Register& rn,
+                          const Operand& operand,
+                          StatusFlags nzcv,
+                          Condition cond,
+                          ConditionalCompareOp op);
+  static bool IsImmConditionalCompare(int64_t immediate);
+
+  void AddSubWithCarry(const Register& rd,
+                       const Register& rn,
+                       const Operand& operand,
+                       FlagsUpdate S,
+                       AddSubWithCarryOp op);
+
+  // Functions for emulating operands not directly supported by the instruction
+  // set.
+  void EmitShift(const Register& rd,
+                 const Register& rn,
+                 Shift shift,
+                 unsigned amount);
+  void EmitExtendShift(const Register& rd,
+                       const Register& rn,
+                       Extend extend,
+                       unsigned left_shift);
+
+  void AddSub(const Register& rd,
+              const Register& rn,
+              const Operand& operand,
+              FlagsUpdate S,
+              AddSubOp op);
+  static bool IsImmAddSub(int64_t immediate);
+
+  static bool IsImmFP32(float imm);
+  static bool IsImmFP64(double imm);
+
+  // Find an appropriate LoadStoreOp or LoadStorePairOp for the specified
+  // registers. Only simple loads are supported; sign- and zero-extension (such
+  // as in LDPSW_x or LDRB_w) are not supported.
+  static inline LoadStoreOp LoadOpFor(const CPURegister& rt);
+  static inline LoadStorePairOp LoadPairOpFor(const CPURegister& rt,
+                                              const CPURegister& rt2);
+  static inline LoadStoreOp StoreOpFor(const CPURegister& rt);
+  static inline LoadStorePairOp StorePairOpFor(const CPURegister& rt,
+                                               const CPURegister& rt2);
+  static inline LoadStorePairNonTemporalOp LoadPairNonTemporalOpFor(
+    const CPURegister& rt, const CPURegister& rt2);
+  static inline LoadStorePairNonTemporalOp StorePairNonTemporalOpFor(
+    const CPURegister& rt, const CPURegister& rt2);
+
+
+ private:
+  // Instruction helpers.
+  void MoveWide(const Register& rd,
+                uint64_t imm,
+                int shift,
+                MoveWideImmediateOp mov_op);
+  void DataProcShiftedRegister(const Register& rd,
+                               const Register& rn,
+                               const Operand& operand,
+                               FlagsUpdate S,
+                               Instr op);
+  void DataProcExtendedRegister(const Register& rd,
+                                const Register& rn,
+                                const Operand& operand,
+                                FlagsUpdate S,
+                                Instr op);
+  void LoadStorePair(const CPURegister& rt,
+                     const CPURegister& rt2,
+                     const MemOperand& addr,
+                     LoadStorePairOp op);
+  void LoadStorePairNonTemporal(const CPURegister& rt,
+                                const CPURegister& rt2,
+                                const MemOperand& addr,
+                                LoadStorePairNonTemporalOp op);
+  // Register the relocation information for the operand and load its value
+  // into rt.
+  void LoadRelocatedValue(const CPURegister& rt,
+                          const Operand& operand,
+                          LoadLiteralOp op);
+  void ConditionalSelect(const Register& rd,
+                         const Register& rn,
+                         const Register& rm,
+                         Condition cond,
+                         ConditionalSelectOp op);
+  void DataProcessing1Source(const Register& rd,
+                             const Register& rn,
+                             DataProcessing1SourceOp op);
+  void DataProcessing3Source(const Register& rd,
+                             const Register& rn,
+                             const Register& rm,
+                             const Register& ra,
+                             DataProcessing3SourceOp op);
+  void FPDataProcessing1Source(const FPRegister& fd,
+                               const FPRegister& fn,
+                               FPDataProcessing1SourceOp op);
+  void FPDataProcessing2Source(const FPRegister& fd,
+                               const FPRegister& fn,
+                               const FPRegister& fm,
+                               FPDataProcessing2SourceOp op);
+  void FPDataProcessing3Source(const FPRegister& fd,
+                               const FPRegister& fn,
+                               const FPRegister& fm,
+                               const FPRegister& fa,
+                               FPDataProcessing3SourceOp op);
+
+  // Label helpers.
+
+  // Return an offset for a label-referencing instruction, typically a branch.
+  int LinkAndGetByteOffsetTo(Label* label);
+
+  // This is the same as LinkAndGetByteOffsetTo, but return an offset
+  // suitable for fields that take instruction offsets.
+  inline int LinkAndGetInstructionOffsetTo(Label* label);
+
+  static const int kStartOfLabelLinkChain = 0;
+
+  // Verify that a label's link chain is intact.
+  void CheckLabelLinkChain(Label const * label);
+
+  void RecordLiteral(int64_t imm, unsigned size);
+
+  // Postpone the generation of the constant pool for the specified number of
+  // instructions.
+  void BlockConstPoolFor(int instructions);
+
+  // Emit the instruction at pc_.
+  void Emit(Instr instruction) {
+    STATIC_ASSERT(sizeof(*pc_) == 1);
+    STATIC_ASSERT(sizeof(instruction) == kInstructionSize);
+    ASSERT((pc_ + sizeof(instruction)) <= (buffer_ + buffer_size_));
+
+    memcpy(pc_, &instruction, sizeof(instruction));
+    pc_ += sizeof(instruction);
+    CheckBuffer();
+  }
+
+  // Emit data inline in the instruction stream.
+  void EmitData(void const * data, unsigned size) {
+    ASSERT(sizeof(*pc_) == 1);
+    ASSERT((pc_ + size) <= (buffer_ + buffer_size_));
+
+    // TODO(all): Somehow register we have some data here. Then we can
+    // disassemble it correctly.
+    memcpy(pc_, data, size);
+    pc_ += size;
+    CheckBuffer();
+  }
+
+  void GrowBuffer();
+  void CheckBuffer();
+
+  // Pc offset of the next buffer check.
+  int next_buffer_check_;
+
+  // Constant pool generation
+  // Pools are emitted in the instruction stream, preferably after unconditional
+  // jumps or after returns from functions (in dead code locations).
+  // If a long code sequence does not contain unconditional jumps, it is
+  // necessary to emit the constant pool before the pool gets too far from the
+  // location it is accessed from. In this case, we emit a jump over the emitted
+  // constant pool.
+  // Constants in the pool may be addresses of functions that gets relocated;
+  // if so, a relocation info entry is associated to the constant pool entry.
+
+  // Repeated checking whether the constant pool should be emitted is rather
+  // expensive. By default we only check again once a number of instructions
+  // has been generated. That also means that the sizing of the buffers is not
+  // an exact science, and that we rely on some slop to not overrun buffers.
+  static const int kCheckPoolIntervalInst = 128;
+  static const int kCheckPoolInterval =
+    kCheckPoolIntervalInst * kInstructionSize;
+
+  // Constants in pools are accessed via pc relative addressing, which can
+  // reach +/-4KB thereby defining a maximum distance between the instruction
+  // and the accessed constant.
+  static const int kMaxDistToPool = 4 * KB;
+  static const int kMaxNumPendingRelocInfo = kMaxDistToPool / kInstructionSize;
+
+
+  // Average distance beetween a constant pool and the first instruction
+  // accessing the constant pool. Longer distance should result in less I-cache
+  // pollution.
+  // In practice the distance will be smaller since constant pool emission is
+  // forced after function return and sometimes after unconditional branches.
+  static const int kAvgDistToPool = kMaxDistToPool - kCheckPoolInterval;
+
+  // Emission of the constant pool may be blocked in some code sequences.
+  int const_pool_blocked_nesting_;  // Block emission if this is not zero.
+  int no_const_pool_before_;  // Block emission before this pc offset.
+
+  // Keep track of the first instruction requiring a constant pool entry
+  // since the previous constant pool was emitted.
+  int first_const_pool_use_;
+
+  // Relocation info generation
+  // Each relocation is encoded as a variable size value
+  static const int kMaxRelocSize = RelocInfoWriter::kMaxSize;
+  RelocInfoWriter reloc_info_writer;
+
+  // Relocation info records are also used during code generation as temporary
+  // containers for constants and code target addresses until they are emitted
+  // to the constant pool. These pending relocation info records are temporarily
+  // stored in a separate buffer until a constant pool is emitted.
+  // If every instruction in a long sequence is accessing the pool, we need one
+  // pending relocation entry per instruction.
+
+  // the buffer of pending relocation info
+  RelocInfo pending_reloc_info_[kMaxNumPendingRelocInfo];
+  // number of pending reloc info entries in the buffer
+  int num_pending_reloc_info_;
+
+  // Relocation for a type-recording IC has the AST id added to it.  This
+  // member variable is a way to pass the information from the call site to
+  // the relocation info.
+  TypeFeedbackId recorded_ast_id_;
+
+  inline TypeFeedbackId RecordedAstId();
+  inline void ClearRecordedAstId();
+
+ protected:
+  // Record the AST id of the CallIC being compiled, so that it can be placed
+  // in the relocation information.
+  void SetRecordedAstId(TypeFeedbackId ast_id) {
+    ASSERT(recorded_ast_id_.IsNone());
+    recorded_ast_id_ = ast_id;
+  }
+
+  // Code generation
+  // The relocation writer's position is at least kGap bytes below the end of
+  // the generated instructions. This is so that multi-instruction sequences do
+  // not have to check for overflow. The same is true for writes of large
+  // relocation info entries, and debug strings encoded in the instruction
+  // stream.
+  static const int kGap = 128;
+
+ private:
+  // TODO(jbramley): VIXL uses next_literal_pool_check_ and
+  // literal_pool_monitor_ to determine when to consider emitting a literal
+  // pool. V8 doesn't use them, so they should either not be here at all, or
+  // should replace or be merged with next_buffer_check_ and
+  // const_pool_blocked_nesting_.
+  Instruction* next_literal_pool_check_;
+  unsigned literal_pool_monitor_;
+
+  PositionsRecorder positions_recorder_;
+  friend class PositionsRecorder;
+  friend class EnsureSpace;
+};
+
+class PatchingAssembler : public Assembler {
+ public:
+  // Create an Assembler with a buffer starting at 'start'.
+  // The buffer size is
+  //   size of instructions to patch + kGap
+  // Where kGap is the distance from which the Assembler tries to grow the
+  // buffer.
+  // If more or fewer instructions than expected are generated or if some
+  // relocation information takes space in the buffer, the PatchingAssembler
+  // will crash trying to grow the buffer.
+  PatchingAssembler(Instruction* start, unsigned count)
+    : Assembler(NULL,
+                reinterpret_cast<byte*>(start),
+                count * kInstructionSize + kGap) {
+    // Block constant pool emission.
+    StartBlockConstPool();
+  }
+
+  PatchingAssembler(byte* start, unsigned count)
+    : Assembler(NULL, start, count * kInstructionSize + kGap) {
+    // Block constant pool emission.
+    StartBlockConstPool();
+  }
+
+  ~PatchingAssembler() {
+    // Const pool should still be blocked.
+    ASSERT(is_const_pool_blocked());
+    EndBlockConstPool();
+    // Verify we have generated the number of instruction we expected.
+    ASSERT((pc_offset() + kGap) == buffer_size_);
+    // Verify no relocation information has been emitted.
+    ASSERT(num_pending_reloc_info() == 0);
+    // Flush the Instruction cache.
+    size_t length = buffer_size_ - kGap;
+    CPU::FlushICache(buffer_, length);
+  }
+};
+
+
+class EnsureSpace BASE_EMBEDDED {
+ public:
+  explicit EnsureSpace(Assembler* assembler) {
+    assembler->CheckBuffer();
+  }
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_A64_ASSEMBLER_A64_H_