Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

1 files changed, 2353 insertions, 0 deletions

diff --git a/qemu/disas/libvixl/a64/assembler-a64.h b/qemu/disas/libvixl/a64/assembler-a64.h
new file mode 100644
index 000000000..35aaf20f7
--- /dev/null
+++ b/qemu/disas/libvixl/a64/assembler-a64.h
@@ -0,0 +1,2353 @@
+// Copyright 2013, ARM Limited
+// 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 ARM Limited 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 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 VIXL_A64_ASSEMBLER_A64_H_
+#define VIXL_A64_ASSEMBLER_A64_H_
+
+#include <list>
+#include <stack>
+
+#include "globals.h"
+#include "utils.h"
+#include "code-buffer.h"
+#include "a64/instructions-a64.h"
+
+namespace vixl {
+
+typedef uint64_t RegList;
+static const int kRegListSizeInBits = sizeof(RegList) * 8;
+
+
+// Registers.
+
+// Some CPURegister methods can return Register and FPRegister types, so we
+// need to declare them in advance.
+class Register;
+class FPRegister;
+
+
+class CPURegister {
+ public:
+  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
+  };
+
+  CPURegister() : code_(0), size_(0), type_(kNoRegister) {
+    VIXL_ASSERT(!IsValid());
+    VIXL_ASSERT(IsNone());
+  }
+
+  CPURegister(unsigned code, unsigned size, RegisterType type)
+      : code_(code), size_(size), type_(type) {
+    VIXL_ASSERT(IsValidOrNone());
+  }
+
+  unsigned code() const {
+    VIXL_ASSERT(IsValid());
+    return code_;
+  }
+
+  RegisterType type() const {
+    VIXL_ASSERT(IsValidOrNone());
+    return type_;
+  }
+
+  RegList Bit() const {
+    VIXL_ASSERT(code_ < (sizeof(RegList) * 8));
+    return IsValid() ? (static_cast<RegList>(1) << code_) : 0;
+  }
+
+  unsigned size() const {
+    VIXL_ASSERT(IsValid());
+    return size_;
+  }
+
+  int SizeInBytes() const {
+    VIXL_ASSERT(IsValid());
+    VIXL_ASSERT(size() % 8 == 0);
+    return size_ / 8;
+  }
+
+  int SizeInBits() const {
+    VIXL_ASSERT(IsValid());
+    return size_;
+  }
+
+  bool Is32Bits() const {
+    VIXL_ASSERT(IsValid());
+    return size_ == 32;
+  }
+
+  bool Is64Bits() const {
+    VIXL_ASSERT(IsValid());
+    return size_ == 64;
+  }
+
+  bool IsValid() const {
+    if (IsValidRegister() || IsValidFPRegister()) {
+      VIXL_ASSERT(!IsNone());
+      return true;
+    } else {
+      VIXL_ASSERT(IsNone());
+      return false;
+    }
+  }
+
+  bool IsValidRegister() const {
+    return IsRegister() &&
+           ((size_ == kWRegSize) || (size_ == kXRegSize)) &&
+           ((code_ < kNumberOfRegisters) || (code_ == kSPRegInternalCode));
+  }
+
+  bool IsValidFPRegister() const {
+    return IsFPRegister() &&
+           ((size_ == kSRegSize) || (size_ == kDRegSize)) &&
+           (code_ < kNumberOfFPRegisters);
+  }
+
+  bool IsNone() const {
+    // kNoRegister types should always have size 0 and code 0.
+    VIXL_ASSERT((type_ != kNoRegister) || (code_ == 0));
+    VIXL_ASSERT((type_ != kNoRegister) || (size_ == 0));
+
+    return type_ == kNoRegister;
+  }
+
+  bool Aliases(const CPURegister& other) const {
+    VIXL_ASSERT(IsValidOrNone() && other.IsValidOrNone());
+    return (code_ == other.code_) && (type_ == other.type_);
+  }
+
+  bool Is(const CPURegister& other) const {
+    VIXL_ASSERT(IsValidOrNone() && other.IsValidOrNone());
+    return Aliases(other) && (size_ == other.size_);
+  }
+
+  bool IsZero() const {
+    VIXL_ASSERT(IsValid());
+    return IsRegister() && (code_ == kZeroRegCode);
+  }
+
+  bool IsSP() const {
+    VIXL_ASSERT(IsValid());
+    return IsRegister() && (code_ == kSPRegInternalCode);
+  }
+
+  bool IsRegister() const {
+    return type_ == kRegister;
+  }
+
+  bool IsFPRegister() const {
+    return type_ == kFPRegister;
+  }
+
+  bool IsW() const { return IsValidRegister() && Is32Bits(); }
+  bool IsX() const { return IsValidRegister() && Is64Bits(); }
+  bool IsS() const { return IsValidFPRegister() && Is32Bits(); }
+  bool IsD() const { return IsValidFPRegister() && Is64Bits(); }
+
+  const Register& W() const;
+  const Register& X() const;
+  const FPRegister& S() const;
+  const FPRegister& D() const;
+
+  bool IsSameSizeAndType(const CPURegister& other) const {
+    return (size_ == other.size_) && (type_ == other.type_);
+  }
+
+ protected:
+  unsigned code_;
+  unsigned size_;
+  RegisterType type_;
+
+ private:
+  bool IsValidOrNone() const {
+    return IsValid() || IsNone();
+  }
+};
+
+
+class Register : public CPURegister {
+ public:
+  Register() : CPURegister() {}
+  explicit Register(const CPURegister& other)
+      : CPURegister(other.code(), other.size(), other.type()) {
+    VIXL_ASSERT(IsValidRegister());
+  }
+  Register(unsigned code, unsigned size)
+      : CPURegister(code, size, kRegister) {}
+
+  bool IsValid() const {
+    VIXL_ASSERT(IsRegister() || IsNone());
+    return IsValidRegister();
+  }
+
+  static const Register& WRegFromCode(unsigned code);
+  static const Register& XRegFromCode(unsigned code);
+
+ private:
+  static const Register wregisters[];
+  static const Register xregisters[];
+};
+
+
+class FPRegister : public CPURegister {
+ public:
+  FPRegister() : CPURegister() {}
+  explicit FPRegister(const CPURegister& other)
+      : CPURegister(other.code(), other.size(), other.type()) {
+    VIXL_ASSERT(IsValidFPRegister());
+  }
+  FPRegister(unsigned code, unsigned size)
+      : CPURegister(code, size, kFPRegister) {}
+
+  bool IsValid() const {
+    VIXL_ASSERT(IsFPRegister() || IsNone());
+    return IsValidFPRegister();
+  }
+
+  static const FPRegister& SRegFromCode(unsigned code);
+  static const FPRegister& DRegFromCode(unsigned code);
+
+ private:
+  static const FPRegister sregisters[];
+  static const FPRegister dregisters[];
+};
+
+
+// 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.
+const Register NoReg;
+const FPRegister NoFPReg;
+const CPURegister NoCPUReg;
+
+
+#define DEFINE_REGISTERS(N)  \
+const Register w##N(N, kWRegSize);  \
+const Register x##N(N, kXRegSize);
+REGISTER_CODE_LIST(DEFINE_REGISTERS)
+#undef DEFINE_REGISTERS
+const Register wsp(kSPRegInternalCode, kWRegSize);
+const Register sp(kSPRegInternalCode, kXRegSize);
+
+
+#define DEFINE_FPREGISTERS(N)  \
+const FPRegister s##N(N, kSRegSize);  \
+const FPRegister d##N(N, kDRegSize);
+REGISTER_CODE_LIST(DEFINE_FPREGISTERS)
+#undef DEFINE_FPREGISTERS
+
+
+// Registers aliases.
+const Register ip0 = x16;
+const Register ip1 = x17;
+const Register lr = x30;
+const Register xzr = x31;
+const Register wzr = w31;
+
+
+// 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);
+
+
+// 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.size()), type_(reg1.type()) {
+    VIXL_ASSERT(AreSameSizeAndType(reg1, reg2, reg3, reg4));
+    VIXL_ASSERT(IsValid());
+  }
+
+  CPURegList(CPURegister::RegisterType type, unsigned size, RegList list)
+      : list_(list), size_(size), type_(type) {
+    VIXL_ASSERT(IsValid());
+  }
+
+  CPURegList(CPURegister::RegisterType type, unsigned size,
+             unsigned first_reg, unsigned last_reg)
+      : size_(size), type_(type) {
+    VIXL_ASSERT(((type == CPURegister::kRegister) &&
+                 (last_reg < kNumberOfRegisters)) ||
+                ((type == CPURegister::kFPRegister) &&
+                 (last_reg < kNumberOfFPRegisters)));
+    VIXL_ASSERT(last_reg >= first_reg);
+    list_ = (UINT64_C(1) << (last_reg + 1)) - 1;
+    list_ &= ~((UINT64_C(1) << first_reg) - 1);
+    VIXL_ASSERT(IsValid());
+  }
+
+  CPURegister::RegisterType type() const {
+    VIXL_ASSERT(IsValid());
+    return type_;
+  }
+
+  // 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) {
+    VIXL_ASSERT(IsValid());
+    VIXL_ASSERT(other.type() == type_);
+    VIXL_ASSERT(other.RegisterSizeInBits() == size_);
+    list_ |= other.list();
+  }
+
+  // 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) {
+    VIXL_ASSERT(IsValid());
+    VIXL_ASSERT(other.type() == type_);
+    VIXL_ASSERT(other.RegisterSizeInBits() == size_);
+    list_ &= ~other.list();
+  }
+
+  // Variants of Combine and Remove which take a single register.
+  void Combine(const CPURegister& other) {
+    VIXL_ASSERT(other.type() == type_);
+    VIXL_ASSERT(other.size() == size_);
+    Combine(other.code());
+  }
+
+  void Remove(const CPURegister& other) {
+    VIXL_ASSERT(other.type() == type_);
+    VIXL_ASSERT(other.size() == size_);
+    Remove(other.code());
+  }
+
+  // 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) {
+    VIXL_ASSERT(IsValid());
+    VIXL_ASSERT(CPURegister(code, size_, type_).IsValid());
+    list_ |= (UINT64_C(1) << code);
+  }
+
+  void Remove(int code) {
+    VIXL_ASSERT(IsValid());
+    VIXL_ASSERT(CPURegister(code, size_, type_).IsValid());
+    list_ &= ~(UINT64_C(1) << code);
+  }
+
+  static CPURegList Union(const CPURegList& list_1, const CPURegList& list_2) {
+    VIXL_ASSERT(list_1.type_ == list_2.type_);
+    VIXL_ASSERT(list_1.size_ == list_2.size_);
+    return CPURegList(list_1.type_, list_1.size_, list_1.list_ | list_2.list_);
+  }
+  static CPURegList Union(const CPURegList& list_1,
+                          const CPURegList& list_2,
+                          const CPURegList& list_3);
+  static CPURegList Union(const CPURegList& list_1,
+                          const CPURegList& list_2,
+                          const CPURegList& list_3,
+                          const CPURegList& list_4);
+
+  static CPURegList Intersection(const CPURegList& list_1,
+                                 const CPURegList& list_2) {
+    VIXL_ASSERT(list_1.type_ == list_2.type_);
+    VIXL_ASSERT(list_1.size_ == list_2.size_);
+    return CPURegList(list_1.type_, list_1.size_, list_1.list_ & list_2.list_);
+  }
+  static CPURegList Intersection(const CPURegList& list_1,
+                                 const CPURegList& list_2,
+                                 const CPURegList& list_3);
+  static CPURegList Intersection(const CPURegList& list_1,
+                                 const CPURegList& list_2,
+                                 const CPURegList& list_3,
+                                 const CPURegList& list_4);
+
+  RegList list() const {
+    VIXL_ASSERT(IsValid());
+    return list_;
+  }
+
+  void set_list(RegList new_list) {
+    VIXL_ASSERT(IsValid());
+    list_ = new_list;
+  }
+
+  // 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);
+
+  bool IsEmpty() const {
+    VIXL_ASSERT(IsValid());
+    return list_ == 0;
+  }
+
+  bool IncludesAliasOf(const CPURegister& other) const {
+    VIXL_ASSERT(IsValid());
+    return (type_ == other.type()) && ((other.Bit() & list_) != 0);
+  }
+
+  bool IncludesAliasOf(int code) const {
+    VIXL_ASSERT(IsValid());
+    return ((code & list_) != 0);
+  }
+
+  int Count() const {
+    VIXL_ASSERT(IsValid());
+    return CountSetBits(list_, kRegListSizeInBits);
+  }
+
+  unsigned RegisterSizeInBits() const {
+    VIXL_ASSERT(IsValid());
+    return size_;
+  }
+
+  unsigned RegisterSizeInBytes() const {
+    int size_in_bits = RegisterSizeInBits();
+    VIXL_ASSERT((size_in_bits % 8) == 0);
+    return size_in_bits / 8;
+  }
+
+  unsigned TotalSizeInBytes() const {
+    VIXL_ASSERT(IsValid());
+    return RegisterSizeInBytes() * Count();
+  }
+
+ private:
+  RegList list_;
+  unsigned size_;
+  CPURegister::RegisterType type_;
+
+  bool IsValid() const;
+};
+
+
+// AAPCS64 callee-saved registers.
+extern const CPURegList kCalleeSaved;
+extern const CPURegList kCalleeSavedFP;
+
+
+// AAPCS64 caller-saved registers. Note that this includes lr.
+extern const CPURegList kCallerSaved;
+extern const CPURegList kCallerSavedFP;
+
+
+// Operand.
+class Operand {
+ public:
+  // #<immediate>
+  // where <immediate> is int64_t.
+  // This is allowed to be an implicit constructor because Operand is
+  // a wrapper class that doesn't normally perform any type conversion.
+  Operand(int64_t immediate);           // 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.
+  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.
+  explicit Operand(Register reg, Extend extend, unsigned shift_amount = 0);
+
+  bool IsImmediate() const;
+  bool IsShiftedRegister() const;
+  bool IsExtendedRegister() const;
+  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.
+  Operand ToExtendedRegister() const;
+
+  int64_t immediate() const {
+    VIXL_ASSERT(IsImmediate());
+    return immediate_;
+  }
+
+  Register reg() const {
+    VIXL_ASSERT(IsShiftedRegister() || IsExtendedRegister());
+    return reg_;
+  }
+
+  Shift shift() const {
+    VIXL_ASSERT(IsShiftedRegister());
+    return shift_;
+  }
+
+  Extend extend() const {
+    VIXL_ASSERT(IsExtendedRegister());
+    return extend_;
+  }
+
+  unsigned shift_amount() const {
+    VIXL_ASSERT(IsShiftedRegister() || IsExtendedRegister());
+    return shift_amount_;
+  }
+
+ private:
+  int64_t immediate_;
+  Register reg_;
+  Shift shift_;
+  Extend extend_;
+  unsigned shift_amount_;
+};
+
+
+// MemOperand represents the addressing mode of a load or store instruction.
+class MemOperand {
+ public:
+  explicit MemOperand(Register base,
+                      int64_t offset = 0,
+                      AddrMode addrmode = Offset);
+  explicit MemOperand(Register base,
+                      Register regoffset,
+                      Shift shift = LSL,
+                      unsigned shift_amount = 0);
+  explicit MemOperand(Register base,
+                      Register regoffset,
+                      Extend extend,
+                      unsigned shift_amount = 0);
+  explicit MemOperand(Register base,
+                      const Operand& offset,
+                      AddrMode addrmode = Offset);
+
+  const Register& base() const { return base_; }
+  const Register& regoffset() const { return regoffset_; }
+  int64_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_; }
+  bool IsImmediateOffset() const;
+  bool IsRegisterOffset() const;
+  bool IsPreIndex() const;
+  bool IsPostIndex() const;
+
+ private:
+  Register base_;
+  Register regoffset_;
+  int64_t offset_;
+  AddrMode addrmode_;
+  Shift shift_;
+  Extend extend_;
+  unsigned shift_amount_;
+};
+
+
+class Label {
+ public:
+  Label() : location_(kLocationUnbound) {}
+  ~Label() {
+    // If the label has been linked to, it needs to be bound to a target.
+    VIXL_ASSERT(!IsLinked() || IsBound());
+  }
+
+  bool IsBound() const { return location_ >= 0; }
+  bool IsLinked() const { return !links_.empty(); }
+
+  ptrdiff_t location() const { return location_; }
+
+ private:
+  // The list of linked instructions is stored in a stack-like structure. We
+  // don't use std::stack directly because it's slow for the common case where
+  // only one or two instructions refer to a label, and labels themselves are
+  // short-lived. This class behaves like std::stack, but the first few links
+  // are preallocated (configured by kPreallocatedLinks).
+  //
+  // If more than N links are required, this falls back to std::stack.
+  class LinksStack {
+   public:
+    LinksStack() : size_(0), links_extended_(NULL) {}
+    ~LinksStack() {
+      delete links_extended_;
+    }
+
+    size_t size() const {
+      return size_;
+    }
+
+    bool empty() const {
+      return size_ == 0;
+    }
+
+    void push(ptrdiff_t value) {
+      if (size_ < kPreallocatedLinks) {
+        links_[size_] = value;
+      } else {
+        if (links_extended_ == NULL) {
+          links_extended_ = new std::stack<ptrdiff_t>();
+        }
+        VIXL_ASSERT(size_ == (links_extended_->size() + kPreallocatedLinks));
+        links_extended_->push(value);
+      }
+      size_++;
+    }
+
+    ptrdiff_t top() const {
+      return (size_ <= kPreallocatedLinks) ? links_[size_ - 1]
+                                           : links_extended_->top();
+    }
+
+    void pop() {
+      size_--;
+      if (size_ >= kPreallocatedLinks) {
+        links_extended_->pop();
+        VIXL_ASSERT(size_ == (links_extended_->size() + kPreallocatedLinks));
+      }
+    }
+
+   private:
+    static const size_t kPreallocatedLinks = 4;
+
+    size_t size_;
+    ptrdiff_t links_[kPreallocatedLinks];
+    std::stack<ptrdiff_t> * links_extended_;
+  };
+
+  void Bind(ptrdiff_t location) {
+    // Labels can only be bound once.
+    VIXL_ASSERT(!IsBound());
+    location_ = location;
+  }
+
+  void AddLink(ptrdiff_t instruction) {
+    // If a label is bound, the assembler already has the information it needs
+    // to write the instruction, so there is no need to add it to links_.
+    VIXL_ASSERT(!IsBound());
+    links_.push(instruction);
+  }
+
+  ptrdiff_t GetAndRemoveNextLink() {
+    VIXL_ASSERT(IsLinked());
+    ptrdiff_t link = links_.top();
+    links_.pop();
+    return link;
+  }
+
+  // The offsets of the instructions that have linked to this label.
+  LinksStack links_;
+  // The label location.
+  ptrdiff_t location_;
+
+  static const ptrdiff_t kLocationUnbound = -1;
+
+  // It is not safe to copy labels, so disable the copy constructor by declaring
+  // it private (without an implementation).
+  Label(const Label&);
+
+  // The Assembler class is responsible for binding and linking labels, since
+  // the stored offsets need to be consistent with the Assembler's buffer.
+  friend class Assembler;
+};
+
+
+// A literal is a 32-bit or 64-bit piece of data stored in the instruction
+// stream and loaded through a pc relative load. The same literal can be
+// referred to by multiple instructions but a literal can only reside at one
+// place in memory. A literal can be used by a load before or after being
+// placed in memory.
+//
+// Internally an offset of 0 is associated with a literal which has been
+// neither used nor placed. Then two possibilities arise:
+//  1) the label is placed, the offset (stored as offset + 1) is used to
+//     resolve any subsequent load using the label.
+//  2) the label is not placed and offset is the offset of the last load using
+//     the literal (stored as -offset -1). If multiple loads refer to this
+//     literal then the last load holds the offset of the preceding load and
+//     all loads form a chain. Once the offset is placed all the loads in the
+//     chain are resolved and future loads fall back to possibility 1.
+class RawLiteral {
+ public:
+  RawLiteral() : size_(0), offset_(0), raw_value_(0) {}
+
+  size_t size() {
+    VIXL_STATIC_ASSERT(kDRegSizeInBytes == kXRegSizeInBytes);
+    VIXL_STATIC_ASSERT(kSRegSizeInBytes == kWRegSizeInBytes);
+    VIXL_ASSERT((size_ == kXRegSizeInBytes) || (size_ == kWRegSizeInBytes));
+    return size_;
+  }
+  uint64_t raw_value64() {
+    VIXL_ASSERT(size_ == kXRegSizeInBytes);
+    return raw_value_;
+  }
+  uint32_t raw_value32() {
+    VIXL_ASSERT(size_ == kWRegSizeInBytes);
+    VIXL_ASSERT(is_uint32(raw_value_) || is_int32(raw_value_));
+    return static_cast<uint32_t>(raw_value_);
+  }
+  bool IsUsed() { return offset_ < 0; }
+  bool IsPlaced() { return offset_ > 0; }
+
+ protected:
+  ptrdiff_t offset() {
+    VIXL_ASSERT(IsPlaced());
+    return offset_ - 1;
+  }
+  void set_offset(ptrdiff_t offset) {
+    VIXL_ASSERT(offset >= 0);
+    VIXL_ASSERT(IsWordAligned(offset));
+    VIXL_ASSERT(!IsPlaced());
+    offset_ = offset + 1;
+  }
+  ptrdiff_t last_use() {
+    VIXL_ASSERT(IsUsed());
+    return -offset_ - 1;
+  }
+  void set_last_use(ptrdiff_t offset) {
+    VIXL_ASSERT(offset >= 0);
+    VIXL_ASSERT(IsWordAligned(offset));
+    VIXL_ASSERT(!IsPlaced());
+    offset_ = -offset - 1;
+  }
+
+  size_t size_;
+  ptrdiff_t offset_;
+  uint64_t raw_value_;
+
+  friend class Assembler;
+};
+
+
+template <typename T>
+class Literal : public RawLiteral {
+ public:
+  explicit Literal(T value) {
+    size_ = sizeof(value);
+    memcpy(&raw_value_, &value, sizeof(value));
+  }
+};
+
+
+// Control whether or not position-independent code should be emitted.
+enum PositionIndependentCodeOption {
+  // All code generated will be position-independent; all branches and
+  // references to labels generated with the Label class will use PC-relative
+  // addressing.
+  PositionIndependentCode,
+
+  // Allow VIXL to generate code that refers to absolute addresses. With this
+  // option, it will not be possible to copy the code buffer and run it from a
+  // different address; code must be generated in its final location.
+  PositionDependentCode,
+
+  // Allow VIXL to assume that the bottom 12 bits of the address will be
+  // constant, but that the top 48 bits may change. This allows `adrp` to
+  // function in systems which copy code between pages, but otherwise maintain
+  // 4KB page alignment.
+  PageOffsetDependentCode
+};
+
+
+// Control how scaled- and unscaled-offset loads and stores are generated.
+enum LoadStoreScalingOption {
+  // Prefer scaled-immediate-offset instructions, but emit unscaled-offset,
+  // register-offset, pre-index or post-index instructions if necessary.
+  PreferScaledOffset,
+
+  // Prefer unscaled-immediate-offset instructions, but emit scaled-offset,
+  // register-offset, pre-index or post-index instructions if necessary.
+  PreferUnscaledOffset,
+
+  // Require scaled-immediate-offset instructions.
+  RequireScaledOffset,
+
+  // Require unscaled-immediate-offset instructions.
+  RequireUnscaledOffset
+};
+
+
+// Assembler.
+class Assembler {
+ public:
+  Assembler(size_t capacity,
+            PositionIndependentCodeOption pic = PositionIndependentCode);
+  Assembler(byte* buffer, size_t capacity,
+            PositionIndependentCodeOption pic = PositionIndependentCode);
+
+  // The destructor asserts that one of the following is true:
+  //  * The Assembler object has not been used.
+  //  * Nothing has been emitted since the last Reset() call.
+  //  * Nothing has been emitted since the last FinalizeCode() call.
+  ~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.
+  void Reset();
+
+  // Finalize a code buffer of generated instructions. This function must be
+  // called before executing or copying code from the buffer.
+  void FinalizeCode();
+
+  // Label.
+  // Bind a label to the current PC.
+  void bind(Label* label);
+
+  // Bind a label to a specified offset from the start of the buffer.
+  void BindToOffset(Label* label, ptrdiff_t offset);
+
+  // Place a literal at the current PC.
+  void place(RawLiteral* literal);
+
+  ptrdiff_t CursorOffset() const {
+    return buffer_->CursorOffset();
+  }
+
+  ptrdiff_t BufferEndOffset() const {
+    return static_cast<ptrdiff_t>(buffer_->capacity());
+  }
+
+  // Return the address of an offset in the buffer.
+  template <typename T>
+  T GetOffsetAddress(ptrdiff_t offset) {
+    VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t));
+    return buffer_->GetOffsetAddress<T>(offset);
+  }
+
+  // Return the address of a bound label.
+  template <typename T>
+  T GetLabelAddress(const Label * label) {
+    VIXL_ASSERT(label->IsBound());
+    VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t));
+    return GetOffsetAddress<T>(label->location());
+  }
+
+  // Return the address of the cursor.
+  template <typename T>
+  T GetCursorAddress() {
+    VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t));
+    return GetOffsetAddress<T>(CursorOffset());
+  }
+
+  // Return the address of the start of the buffer.
+  template <typename T>
+  T GetStartAddress() {
+    VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t));
+    return GetOffsetAddress<T>(0);
+  }
+
+  // Instruction set functions.
+
+  // Branch / Jump instructions.
+  // Branch to register.
+  void br(const Register& xn);
+
+  // Branch with 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 with link to label.
+  void bl(Label* label);
+
+  // Branch with link to PC offset.
+  void bl(int imm26);
+
+  // Compare and branch to label if zero.
+  void cbz(const Register& rt, Label* label);
+
+  // Compare and branch to PC offset if zero.
+  void cbz(const Register& rt, int imm19);
+
+  // Compare and branch to label if not zero.
+  void cbnz(const Register& rt, Label* label);
+
+  // Compare and branch to PC offset if not zero.
+  void cbnz(const Register& rt, int imm19);
+
+  // Test bit and branch to label if zero.
+  void tbz(const Register& rt, unsigned bit_pos, Label* label);
+
+  // Test bit and branch to PC offset if zero.
+  void tbz(const Register& rt, unsigned bit_pos, int imm14);
+
+  // Test bit and branch to label if not zero.
+  void tbnz(const Register& rt, unsigned bit_pos, Label* label);
+
+  // Test bit and branch to PC offset if not zero.
+  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).
+
+  // Calculate the address of a label.
+  void adr(const Register& rd, Label* label);
+
+  // Calculate the address of a PC offset.
+  void adr(const Register& rd, int imm21);
+
+  // Calculate the page address of a label.
+  void adrp(const Register& rd, Label* label);
+
+  // Calculate the page address of a PC offset.
+  void adrp(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 by variable.
+  void lslv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Logical shift right by variable.
+  void lsrv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Arithmetic shift right by variable.
+  void asrv(const Register& rd, const Register& rn, const Register& rm);
+
+  // Rotate right by 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) {
+    VIXL_ASSERT(width >= 1);
+    VIXL_ASSERT(lsb + width <= rn.size());
+    bfm(rd, rn, (rd.size() - lsb) & (rd.size() - 1), width - 1);
+  }
+
+  // Bitfield extract and insert low.
+  void bfxil(const Register& rd,
+             const Register& rn,
+             unsigned lsb,
+             unsigned width) {
+    VIXL_ASSERT(width >= 1);
+    VIXL_ASSERT(lsb + width <= rn.size());
+    bfm(rd, rn, lsb, lsb + width - 1);
+  }
+
+  // Sbfm aliases.
+  // Arithmetic shift right.
+  void asr(const Register& rd, const Register& rn, unsigned shift) {
+    VIXL_ASSERT(shift < rd.size());
+    sbfm(rd, rn, shift, rd.size() - 1);
+  }
+
+  // Signed bitfield insert with zero at right.
+  void sbfiz(const Register& rd,
+             const Register& rn,
+             unsigned lsb,
+             unsigned width) {
+    VIXL_ASSERT(width >= 1);
+    VIXL_ASSERT(lsb + width <= rn.size());
+    sbfm(rd, rn, (rd.size() - lsb) & (rd.size() - 1), width - 1);
+  }
+
+  // Signed bitfield extract.
+  void sbfx(const Register& rd,
+            const Register& rn,
+            unsigned lsb,
+            unsigned width) {
+    VIXL_ASSERT(width >= 1);
+    VIXL_ASSERT(lsb + width <= rn.size());
+    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.size();
+    VIXL_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) {
+    VIXL_ASSERT(shift < rd.size());
+    ubfm(rd, rn, shift, rd.size() - 1);
+  }
+
+  // Unsigned bitfield insert with zero at right.
+  void ubfiz(const Register& rd,
+             const Register& rn,
+             unsigned lsb,
+             unsigned width) {
+    VIXL_ASSERT(width >= 1);
+    VIXL_ASSERT(lsb + width <= rn.size());
+    ubfm(rd, rn, (rd.size() - lsb) & (rd.size() - 1), width - 1);
+  }
+
+  // Unsigned bitfield extract.
+  void ubfx(const Register& rd,
+            const Register& rn,
+            unsigned lsb,
+            unsigned width) {
+    VIXL_ASSERT(width >= 1);
+    VIXL_ASSERT(lsb + width <= rn.size());
+    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 mask: 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);
+
+  // Rotate right.
+  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);
+
+  // Multiply.
+  void mul(const Register& rd, const Register& rn, const Register& rm);
+
+  // Negated multiply.
+  void mneg(const Register& rd, const Register& rn, const Register& rm);
+
+  // Signed long multiply: 32 x 32 -> 64-bit.
+  void smull(const Register& rd, const Register& rn, const Register& rm);
+
+  // Signed multiply high: 64 x 64 -> 64-bit <127:64>.
+  void smulh(const Register& xd, const Register& xn, const Register& xm);
+
+  // Multiply and accumulate.
+  void madd(const Register& rd,
+            const Register& rn,
+            const Register& rm,
+            const Register& ra);
+
+  // Multiply and subtract.
+  void msub(const Register& rd,
+            const Register& rn,
+            const Register& rm,
+            const Register& ra);
+
+  // Signed long multiply and accumulate: 32 x 32 + 64 -> 64-bit.
+  void smaddl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Unsigned long multiply and accumulate: 32 x 32 + 64 -> 64-bit.
+  void umaddl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Signed long multiply and subtract: 64 - (32 x 32) -> 64-bit.
+  void smsubl(const Register& rd,
+              const Register& rn,
+              const Register& rm,
+              const Register& ra);
+
+  // Unsigned long multiply and subtract: 64 - (32 x 32) -> 64-bit.
+  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 reverse.
+  void rbit(const Register& rd, const Register& rn);
+
+  // Reverse bytes in 16-bit half words.
+  void rev16(const Register& rd, const Register& rn);
+
+  // Reverse bytes in 32-bit words.
+  void rev32(const Register& rd, const Register& rn);
+
+  // Reverse bytes.
+  void rev(const Register& rd, const Register& rn);
+
+  // Count leading zeroes.
+  void clz(const Register& rd, const Register& rn);
+
+  // Count leading sign bits.
+  void cls(const Register& rd, const Register& rn);
+
+  // Memory instructions.
+  // Load integer or FP register.
+  void ldr(const CPURegister& rt, const MemOperand& src,
+           LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Store integer or FP register.
+  void str(const CPURegister& rt, const MemOperand& dst,
+           LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Load word with sign extension.
+  void ldrsw(const Register& rt, const MemOperand& src,
+             LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Load byte.
+  void ldrb(const Register& rt, const MemOperand& src,
+            LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Store byte.
+  void strb(const Register& rt, const MemOperand& dst,
+            LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Load byte with sign extension.
+  void ldrsb(const Register& rt, const MemOperand& src,
+             LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Load half-word.
+  void ldrh(const Register& rt, const MemOperand& src,
+            LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Store half-word.
+  void strh(const Register& rt, const MemOperand& dst,
+            LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Load half-word with sign extension.
+  void ldrsh(const Register& rt, const MemOperand& src,
+             LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Load integer or FP register (with unscaled offset).
+  void ldur(const CPURegister& rt, const MemOperand& src,
+            LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Store integer or FP register (with unscaled offset).
+  void stur(const CPURegister& rt, const MemOperand& src,
+            LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Load word with sign extension.
+  void ldursw(const Register& rt, const MemOperand& src,
+              LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Load byte (with unscaled offset).
+  void ldurb(const Register& rt, const MemOperand& src,
+             LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Store byte (with unscaled offset).
+  void sturb(const Register& rt, const MemOperand& dst,
+             LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Load byte with sign extension (and unscaled offset).
+  void ldursb(const Register& rt, const MemOperand& src,
+              LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Load half-word (with unscaled offset).
+  void ldurh(const Register& rt, const MemOperand& src,
+             LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Store half-word (with unscaled offset).
+  void sturh(const Register& rt, const MemOperand& dst,
+             LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Load half-word with sign extension (and unscaled offset).
+  void ldursh(const Register& rt, const MemOperand& src,
+              LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // 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 integer or FP register from literal pool.
+  void ldr(const CPURegister& rt, RawLiteral* literal);
+
+  // Load word with sign extension from literal pool.
+  void ldrsw(const Register& rt, RawLiteral* literal);
+
+  // Load integer or FP register from pc + imm19 << 2.
+  void ldr(const CPURegister& rt, int imm19);
+
+  // Load word with sign extension from pc + imm19 << 2.
+  void ldrsw(const Register& rt, int imm19);
+
+  // Store exclusive byte.
+  void stxrb(const Register& rs, const Register& rt, const MemOperand& dst);
+
+  // Store exclusive half-word.
+  void stxrh(const Register& rs, const Register& rt, const MemOperand& dst);
+
+  // Store exclusive register.
+  void stxr(const Register& rs, const Register& rt, const MemOperand& dst);
+
+  // Load exclusive byte.
+  void ldxrb(const Register& rt, const MemOperand& src);
+
+  // Load exclusive half-word.
+  void ldxrh(const Register& rt, const MemOperand& src);
+
+  // Load exclusive register.
+  void ldxr(const Register& rt, const MemOperand& src);
+
+  // Store exclusive register pair.
+  void stxp(const Register& rs,
+            const Register& rt,
+            const Register& rt2,
+            const MemOperand& dst);
+
+  // Load exclusive register pair.
+  void ldxp(const Register& rt, const Register& rt2, const MemOperand& src);
+
+  // Store-release exclusive byte.
+  void stlxrb(const Register& rs, const Register& rt, const MemOperand& dst);
+
+  // Store-release exclusive half-word.
+  void stlxrh(const Register& rs, const Register& rt, const MemOperand& dst);
+
+  // Store-release exclusive register.
+  void stlxr(const Register& rs, const Register& rt, const MemOperand& dst);
+
+  // Load-acquire exclusive byte.
+  void ldaxrb(const Register& rt, const MemOperand& src);
+
+  // Load-acquire exclusive half-word.
+  void ldaxrh(const Register& rt, const MemOperand& src);
+
+  // Load-acquire exclusive register.
+  void ldaxr(const Register& rt, const MemOperand& src);
+
+  // Store-release exclusive register pair.
+  void stlxp(const Register& rs,
+             const Register& rt,
+             const Register& rt2,
+             const MemOperand& dst);
+
+  // Load-acquire exclusive register pair.
+  void ldaxp(const Register& rt, const Register& rt2, const MemOperand& src);
+
+  // Store-release byte.
+  void stlrb(const Register& rt, const MemOperand& dst);
+
+  // Store-release half-word.
+  void stlrh(const Register& rt, const MemOperand& dst);
+
+  // Store-release register.
+  void stlr(const Register& rt, const MemOperand& dst);
+
+  // Load-acquire byte.
+  void ldarb(const Register& rt, const MemOperand& src);
+
+  // Load-acquire half-word.
+  void ldarh(const Register& rt, const MemOperand& src);
+
+  // Load-acquire register.
+  void ldar(const Register& rt, const MemOperand& src);
+
+  // Prefetch memory.
+  void prfm(PrefetchOperation op, const MemOperand& addr,
+            LoadStoreScalingOption option = PreferScaledOffset);
+
+  // Prefetch memory (with unscaled offset).
+  void prfum(PrefetchOperation op, const MemOperand& addr,
+             LoadStoreScalingOption option = PreferUnscaledOffset);
+
+  // Prefetch memory in the literal pool.
+  void prfm(PrefetchOperation op, RawLiteral* literal);
+
+  // Prefetch from pc + imm19 << 2.
+  void prfm(PrefetchOperation op, int imm19);
+
+  // 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 immediate and keep.
+  void movk(const Register& rd, uint64_t imm, int shift = -1) {
+    MoveWide(rd, imm, shift, MOVK);
+  }
+
+  // Move inverted immediate.
+  void movn(const Register& rd, uint64_t imm, int shift = -1) {
+    MoveWide(rd, imm, shift, MOVN);
+  }
+
+  // Move immediate.
+  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 inverted 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);
+
+  // Clear exclusive monitor.
+  void clrex(int imm4 = 0xf);
+
+  // 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.
+  // No-op.
+  void nop() {
+    hint(NOP);
+  }
+
+  // FP instructions.
+  // Move double precision immediate to FP register.
+  void fmov(const FPRegister& fd, double imm);
+
+  // Move single precision immediate to FP register.
+  void fmov(const FPRegister& fd, float imm);
+
+  // Move FP register to register.
+  void fmov(const Register& rd, const FPRegister& fn);
+
+  // Move register to FP register.
+  void fmov(const FPRegister& fd, const Register& rn);
+
+  // Move FP register to FP register.
+  void fmov(const FPRegister& fd, const 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 number.
+  void fmaxnm(const FPRegister& fd, const FPRegister& fn, const FPRegister& fm);
+
+  // FP minimum number.
+  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 (implicit rounding).
+  void frinti(const FPRegister& fd, const FPRegister& fn);
+
+  // FP round to integer (toward minus infinity).
+  void frintm(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 (toward plus infinity).
+  void frintp(const FPRegister& fd, const FPRegister& fn);
+
+  // FP round to integer (exact, implicit rounding).
+  void frintx(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 signed integer (nearest with ties to away).
+  void fcvtas(const Register& rd, 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 (round towards -infinity).
+  void fcvtms(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 (nearest with ties to even).
+  void fcvtns(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 (round towards zero).
+  void fcvtzs(const Register& rd, const FPRegister& fn);
+
+  // Convert FP to unsigned integer (round towards zero).
+  void fcvtzu(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);
+
+  // Emit generic instructions.
+  // Emit raw instructions into the instruction stream.
+  void dci(Instr raw_inst) { Emit(raw_inst); }
+
+  // Emit 32 bits of data into the instruction stream.
+  void dc32(uint32_t data) {
+    VIXL_ASSERT(buffer_monitor_ > 0);
+    buffer_->Emit32(data);
+  }
+
+  // Emit 64 bits of data into the instruction stream.
+  void dc64(uint64_t data) {
+    VIXL_ASSERT(buffer_monitor_ > 0);
+    buffer_->Emit64(data);
+  }
+
+  // Copy a string into the instruction stream, including the terminating NULL
+  // character. The instruction pointer is then aligned correctly for
+  // subsequent instructions.
+  void EmitString(const char * string) {
+    VIXL_ASSERT(string != NULL);
+    VIXL_ASSERT(buffer_monitor_ > 0);
+
+    buffer_->EmitString(string);
+    buffer_->Align();
+  }
+
+  // Code generation helpers.
+
+  // Register encoding.
+  static Instr Rd(CPURegister rd) {
+    VIXL_ASSERT(rd.code() != kSPRegInternalCode);
+    return rd.code() << Rd_offset;
+  }
+
+  static Instr Rn(CPURegister rn) {
+    VIXL_ASSERT(rn.code() != kSPRegInternalCode);
+    return rn.code() << Rn_offset;
+  }
+
+  static Instr Rm(CPURegister rm) {
+    VIXL_ASSERT(rm.code() != kSPRegInternalCode);
+    return rm.code() << Rm_offset;
+  }
+
+  static Instr Ra(CPURegister ra) {
+    VIXL_ASSERT(ra.code() != kSPRegInternalCode);
+    return ra.code() << Ra_offset;
+  }
+
+  static Instr Rt(CPURegister rt) {
+    VIXL_ASSERT(rt.code() != kSPRegInternalCode);
+    return rt.code() << Rt_offset;
+  }
+
+  static Instr Rt2(CPURegister rt2) {
+    VIXL_ASSERT(rt2.code() != kSPRegInternalCode);
+    return rt2.code() << Rt2_offset;
+  }
+
+  static Instr Rs(CPURegister rs) {
+    VIXL_ASSERT(rs.code() != kSPRegInternalCode);
+    return rs.code() << Rs_offset;
+  }
+
+  // These encoding functions allow the stack pointer to be encoded, and
+  // disallow the zero register.
+  static Instr RdSP(Register rd) {
+    VIXL_ASSERT(!rd.IsZero());
+    return (rd.code() & kRegCodeMask) << Rd_offset;
+  }
+
+  static Instr RnSP(Register rn) {
+    VIXL_ASSERT(!rn.IsZero());
+    return (rn.code() & kRegCodeMask) << Rn_offset;
+  }
+
+  // Flags encoding.
+  static Instr Flags(FlagsUpdate S) {
+    if (S == SetFlags) {
+      return 1 << FlagsUpdate_offset;
+    } else if (S == LeaveFlags) {
+      return 0 << FlagsUpdate_offset;
+    }
+    VIXL_UNREACHABLE();
+    return 0;
+  }
+
+  static Instr Cond(Condition cond) {
+    return cond << Condition_offset;
+  }
+
+  // PC-relative address encoding.
+  static Instr ImmPCRelAddress(int imm21) {
+    VIXL_ASSERT(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);
+  }
+
+  // Branch encoding.
+  static Instr ImmUncondBranch(int imm26) {
+    VIXL_ASSERT(is_int26(imm26));
+    return truncate_to_int26(imm26) << ImmUncondBranch_offset;
+  }
+
+  static Instr ImmCondBranch(int imm19) {
+    VIXL_ASSERT(is_int19(imm19));
+    return truncate_to_int19(imm19) << ImmCondBranch_offset;
+  }
+
+  static Instr ImmCmpBranch(int imm19) {
+    VIXL_ASSERT(is_int19(imm19));
+    return truncate_to_int19(imm19) << ImmCmpBranch_offset;
+  }
+
+  static Instr ImmTestBranch(int imm14) {
+    VIXL_ASSERT(is_int14(imm14));
+    return truncate_to_int14(imm14) << ImmTestBranch_offset;
+  }
+
+  static Instr ImmTestBranchBit(unsigned bit_pos) {
+    VIXL_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;
+  }
+
+  // Data Processing encoding.
+  static Instr SF(Register rd) {
+      return rd.Is64Bits() ? SixtyFourBits : ThirtyTwoBits;
+  }
+
+  static Instr ImmAddSub(int64_t imm) {
+    VIXL_ASSERT(IsImmAddSub(imm));
+    if (is_uint12(imm)) {  // No shift required.
+      return imm << ImmAddSub_offset;
+    } else {
+      return ((imm >> 12) << ImmAddSub_offset) | (1 << ShiftAddSub_offset);
+    }
+  }
+
+  static Instr ImmS(unsigned imms, unsigned reg_size) {
+    VIXL_ASSERT(((reg_size == kXRegSize) && is_uint6(imms)) ||
+           ((reg_size == kWRegSize) && is_uint5(imms)));
+    USE(reg_size);
+    return imms << ImmS_offset;
+  }
+
+  static Instr ImmR(unsigned immr, unsigned reg_size) {
+    VIXL_ASSERT(((reg_size == kXRegSize) && is_uint6(immr)) ||
+           ((reg_size == kWRegSize) && is_uint5(immr)));
+    USE(reg_size);
+    VIXL_ASSERT(is_uint6(immr));
+    return immr << ImmR_offset;
+  }
+
+  static Instr ImmSetBits(unsigned imms, unsigned reg_size) {
+    VIXL_ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize));
+    VIXL_ASSERT(is_uint6(imms));
+    VIXL_ASSERT((reg_size == kXRegSize) || is_uint6(imms + 3));
+    USE(reg_size);
+    return imms << ImmSetBits_offset;
+  }
+
+  static Instr ImmRotate(unsigned immr, unsigned reg_size) {
+    VIXL_ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize));
+    VIXL_ASSERT(((reg_size == kXRegSize) && is_uint6(immr)) ||
+           ((reg_size == kWRegSize) && is_uint5(immr)));
+    USE(reg_size);
+    return immr << ImmRotate_offset;
+  }
+
+  static Instr ImmLLiteral(int imm19) {
+    VIXL_ASSERT(is_int19(imm19));
+    return truncate_to_int19(imm19) << ImmLLiteral_offset;
+  }
+
+  static Instr BitN(unsigned bitn, unsigned reg_size) {
+    VIXL_ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize));
+    VIXL_ASSERT((reg_size == kXRegSize) || (bitn == 0));
+    USE(reg_size);
+    return bitn << BitN_offset;
+  }
+
+  static Instr ShiftDP(Shift shift) {
+    VIXL_ASSERT(shift == LSL || shift == LSR || shift == ASR || shift == ROR);
+    return shift << ShiftDP_offset;
+  }
+
+  static Instr ImmDPShift(unsigned amount) {
+    VIXL_ASSERT(is_uint6(amount));
+    return amount << ImmDPShift_offset;
+  }
+
+  static Instr ExtendMode(Extend extend) {
+    return extend << ExtendMode_offset;
+  }
+
+  static Instr ImmExtendShift(unsigned left_shift) {
+    VIXL_ASSERT(left_shift <= 4);
+    return left_shift << ImmExtendShift_offset;
+  }
+
+  static Instr ImmCondCmp(unsigned imm) {
+    VIXL_ASSERT(is_uint5(imm));
+    return imm << ImmCondCmp_offset;
+  }
+
+  static Instr Nzcv(StatusFlags nzcv) {
+    return ((nzcv >> Flags_offset) & 0xf) << Nzcv_offset;
+  }
+
+  // MemOperand offset encoding.
+  static Instr ImmLSUnsigned(int imm12) {
+    VIXL_ASSERT(is_uint12(imm12));
+    return imm12 << ImmLSUnsigned_offset;
+  }
+
+  static Instr ImmLS(int imm9) {
+    VIXL_ASSERT(is_int9(imm9));
+    return truncate_to_int9(imm9) << ImmLS_offset;
+  }
+
+  static Instr ImmLSPair(int imm7, LSDataSize size) {
+    VIXL_ASSERT(((imm7 >> size) << size) == imm7);
+    int scaled_imm7 = imm7 >> size;
+    VIXL_ASSERT(is_int7(scaled_imm7));
+    return truncate_to_int7(scaled_imm7) << ImmLSPair_offset;
+  }
+
+  static Instr ImmShiftLS(unsigned shift_amount) {
+    VIXL_ASSERT(is_uint1(shift_amount));
+    return shift_amount << ImmShiftLS_offset;
+  }
+
+  static Instr ImmPrefetchOperation(int imm5) {
+    VIXL_ASSERT(is_uint5(imm5));
+    return imm5 << ImmPrefetchOperation_offset;
+  }
+
+  static Instr ImmException(int imm16) {
+    VIXL_ASSERT(is_uint16(imm16));
+    return imm16 << ImmException_offset;
+  }
+
+  static Instr ImmSystemRegister(int imm15) {
+    VIXL_ASSERT(is_uint15(imm15));
+    return imm15 << ImmSystemRegister_offset;
+  }
+
+  static Instr ImmHint(int imm7) {
+    VIXL_ASSERT(is_uint7(imm7));
+    return imm7 << ImmHint_offset;
+  }
+
+  static Instr CRm(int imm4) {
+    VIXL_ASSERT(is_uint4(imm4));
+    return imm4 << CRm_offset;
+  }
+
+  static Instr ImmBarrierDomain(int imm2) {
+    VIXL_ASSERT(is_uint2(imm2));
+    return imm2 << ImmBarrierDomain_offset;
+  }
+
+  static Instr ImmBarrierType(int imm2) {
+    VIXL_ASSERT(is_uint2(imm2));
+    return imm2 << ImmBarrierType_offset;
+  }
+
+  static LSDataSize CalcLSDataSize(LoadStoreOp op) {
+    VIXL_ASSERT((SizeLS_offset + SizeLS_width) == (kInstructionSize * 8));
+    return static_cast<LSDataSize>(op >> SizeLS_offset);
+  }
+
+  // Move immediates encoding.
+  static Instr ImmMoveWide(uint64_t imm) {
+    VIXL_ASSERT(is_uint16(imm));
+    return imm << ImmMoveWide_offset;
+  }
+
+  static Instr ShiftMoveWide(int64_t shift) {
+    VIXL_ASSERT(is_uint2(shift));
+    return shift << ShiftMoveWide_offset;
+  }
+
+  // FP Immediates.
+  static Instr ImmFP32(float imm);
+  static Instr ImmFP64(double imm);
+
+  // FP register type.
+  static Instr FPType(FPRegister fd) {
+    return fd.Is64Bits() ? FP64 : FP32;
+  }
+
+  static Instr FPScale(unsigned scale) {
+    VIXL_ASSERT(is_uint6(scale));
+    return scale << FPScale_offset;
+  }
+
+  // Immediate field checking helpers.
+  static bool IsImmAddSub(int64_t immediate);
+  static bool IsImmConditionalCompare(int64_t immediate);
+  static bool IsImmFP32(float imm);
+  static bool IsImmFP64(double imm);
+  static bool IsImmLogical(uint64_t value,
+                           unsigned width,
+                           unsigned* n = NULL,
+                           unsigned* imm_s = NULL,
+                           unsigned* imm_r = NULL);
+  static bool IsImmLSPair(int64_t offset, LSDataSize size);
+  static bool IsImmLSScaled(int64_t offset, LSDataSize size);
+  static bool IsImmLSUnscaled(int64_t offset);
+  static bool IsImmMovn(uint64_t imm, unsigned reg_size);
+  static bool IsImmMovz(uint64_t imm, unsigned reg_size);
+
+  // Size of the code generated since label to the current position.
+  size_t SizeOfCodeGeneratedSince(Label* label) const {
+    VIXL_ASSERT(label->IsBound());
+    return buffer_->OffsetFrom(label->location());
+  }
+
+  size_t SizeOfCodeGenerated() const {
+    return buffer_->CursorOffset();
+  }
+
+  size_t BufferCapacity() const { return buffer_->capacity(); }
+
+  size_t RemainingBufferSpace() const { return buffer_->RemainingBytes(); }
+
+  void EnsureSpaceFor(size_t amount) {
+    if (buffer_->RemainingBytes() < amount) {
+      size_t capacity = buffer_->capacity();
+      size_t size = buffer_->CursorOffset();
+      do {
+        // TODO(all): refine.
+        capacity *= 2;
+      } while ((capacity - size) <  amount);
+      buffer_->Grow(capacity);
+    }
+  }
+
+#ifdef VIXL_DEBUG
+  void AcquireBuffer() {
+    VIXL_ASSERT(buffer_monitor_ >= 0);
+    buffer_monitor_++;
+  }
+
+  void ReleaseBuffer() {
+    buffer_monitor_--;
+    VIXL_ASSERT(buffer_monitor_ >= 0);
+  }
+#endif
+
+  PositionIndependentCodeOption pic() const {
+    return pic_;
+  }
+
+  bool AllowPageOffsetDependentCode() const {
+    return (pic() == PageOffsetDependentCode) ||
+           (pic() == PositionDependentCode);
+  }
+
+  static const Register& AppropriateZeroRegFor(const CPURegister& reg) {
+    return reg.Is64Bits() ? xzr : wzr;
+  }
+
+
+ protected:
+  void LoadStore(const CPURegister& rt,
+                 const MemOperand& addr,
+                 LoadStoreOp op,
+                 LoadStoreScalingOption option = PreferScaledOffset);
+
+  void LoadStorePair(const CPURegister& rt,
+                     const CPURegister& rt2,
+                     const MemOperand& addr,
+                     LoadStorePairOp op);
+
+  void Prefetch(PrefetchOperation op,
+                const MemOperand& addr,
+                LoadStoreScalingOption option = PreferScaledOffset);
+
+  // TODO(all): The third parameter should be passed by reference but gcc 4.8.2
+  // reports a bogus uninitialised warning then.
+  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);
+
+  void ConditionalCompare(const Register& rn,
+                          const Operand& operand,
+                          StatusFlags nzcv,
+                          Condition cond,
+                          ConditionalCompareOp op);
+
+  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);
+
+  // 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 LoadStoreOp LoadOpFor(const CPURegister& rt);
+  static LoadStorePairOp LoadPairOpFor(const CPURegister& rt,
+                                       const CPURegister& rt2);
+  static LoadStoreOp StoreOpFor(const CPURegister& rt);
+  static LoadStorePairOp StorePairOpFor(const CPURegister& rt,
+                                        const CPURegister& rt2);
+  static LoadStorePairNonTemporalOp LoadPairNonTemporalOpFor(
+    const CPURegister& rt, const CPURegister& rt2);
+  static LoadStorePairNonTemporalOp StorePairNonTemporalOpFor(
+    const CPURegister& rt, const CPURegister& rt2);
+  static LoadLiteralOp LoadLiteralOpFor(const CPURegister& rt);
+
+
+ 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 LoadStorePairNonTemporal(const CPURegister& rt,
+                                const CPURegister& rt2,
+                                const MemOperand& addr,
+                                LoadStorePairNonTemporalOp op);
+  void LoadLiteral(const CPURegister& rt, uint64_t imm, 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);
+
+  // Encode the specified MemOperand for the specified access size and scaling
+  // preference.
+  Instr LoadStoreMemOperand(const MemOperand& addr,
+                            LSDataSize size,
+                            LoadStoreScalingOption option);
+
+  // Link the current (not-yet-emitted) instruction to the specified label, then
+  // return an offset to be encoded in the instruction. If the label is not yet
+  // bound, an offset of 0 is returned.
+  ptrdiff_t LinkAndGetByteOffsetTo(Label * label);
+  ptrdiff_t LinkAndGetInstructionOffsetTo(Label * label);
+  ptrdiff_t LinkAndGetPageOffsetTo(Label * label);
+
+  // A common implementation for the LinkAndGet<Type>OffsetTo helpers.
+  template <int element_shift>
+  ptrdiff_t LinkAndGetOffsetTo(Label* label);
+
+  // Literal load offset are in words (32-bit).
+  ptrdiff_t LinkAndGetWordOffsetTo(RawLiteral* literal);
+
+  // Emit the instruction in buffer_.
+  void Emit(Instr instruction) {
+    VIXL_STATIC_ASSERT(sizeof(instruction) == kInstructionSize);
+    VIXL_ASSERT(buffer_monitor_ > 0);
+    buffer_->Emit32(instruction);
+  }
+
+  // Buffer where the code is emitted.
+  CodeBuffer* buffer_;
+  PositionIndependentCodeOption pic_;
+
+#ifdef VIXL_DEBUG
+  int64_t buffer_monitor_;
+#endif
+};
+
+
+// All Assembler emits MUST acquire/release the underlying code buffer. The
+// helper scope below will do so and optionally ensure the buffer is big enough
+// to receive the emit. It is possible to request the scope not to perform any
+// checks (kNoCheck) if for example it is known in advance the buffer size is
+// adequate or there is some other size checking mechanism in place.
+class CodeBufferCheckScope {
+ public:
+  // Tell whether or not the scope needs to ensure the associated CodeBuffer
+  // has enough space for the requested size.
+  enum CheckPolicy {
+    kNoCheck,
+    kCheck
+  };
+
+  // Tell whether or not the scope should assert the amount of code emitted
+  // within the scope is consistent with the requested amount.
+  enum AssertPolicy {
+    kNoAssert,    // No assert required.
+    kExactSize,   // The code emitted must be exactly size bytes.
+    kMaximumSize  // The code emitted must be at most size bytes.
+  };
+
+  CodeBufferCheckScope(Assembler* assm,
+                       size_t size,
+                       CheckPolicy check_policy = kCheck,
+                       AssertPolicy assert_policy = kMaximumSize)
+      : assm_(assm) {
+    if (check_policy == kCheck) assm->EnsureSpaceFor(size);
+#ifdef VIXL_DEBUG
+    assm->bind(&start_);
+    size_ = size;
+    assert_policy_ = assert_policy;
+    assm->AcquireBuffer();
+#else
+    USE(assert_policy);
+#endif
+  }
+
+  // This is a shortcut for CodeBufferCheckScope(assm, 0, kNoCheck, kNoAssert).
+  explicit CodeBufferCheckScope(Assembler* assm) : assm_(assm) {
+#ifdef VIXL_DEBUG
+    size_ = 0;
+    assert_policy_ = kNoAssert;
+    assm->AcquireBuffer();
+#endif
+  }
+
+  ~CodeBufferCheckScope() {
+#ifdef VIXL_DEBUG
+    assm_->ReleaseBuffer();
+    switch (assert_policy_) {
+      case kNoAssert: break;
+      case kExactSize:
+        VIXL_ASSERT(assm_->SizeOfCodeGeneratedSince(&start_) == size_);
+        break;
+      case kMaximumSize:
+        VIXL_ASSERT(assm_->SizeOfCodeGeneratedSince(&start_) <= size_);
+        break;
+      default:
+        VIXL_UNREACHABLE();
+    }
+#endif
+  }
+
+ protected:
+  Assembler* assm_;
+#ifdef VIXL_DEBUG
+  Label start_;
+  size_t size_;
+  AssertPolicy assert_policy_;
+#endif
+};
+
+}  // namespace vixl
+
+#endif  // VIXL_A64_ASSEMBLER_A64_H_