// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// Classes that describe assembly patterns as used by inline caches.

#ifndef VM_INSTRUCTIONS_ARM_H_
#define VM_INSTRUCTIONS_ARM_H_

#ifndef VM_INSTRUCTIONS_H_
#error Do not include instructions_arm.h directly; use instructions.h instead.
#endif

#include "vm/constants_arm.h"
#include "vm/object.h"

namespace dart {

class InstructionPattern : public AllStatic {
 public:
  // Decodes a load sequence ending at 'end' (the last instruction of the
  // load sequence is the instruction before the one at end).  Returns the
  // address of the first instruction in the sequence.  Returns the register
  // being loaded and the loaded object in the output parameters 'reg' and
  // 'obj' respectively.
  static uword DecodeLoadObject(uword end,
                                const ObjectPool& object_pool,
                                Register* reg,
                                Object* obj);

  // Decodes a load sequence ending at 'end' (the last instruction of the
  // load sequence is the instruction before the one at end).  Returns the
  // address of the first instruction in the sequence.  Returns the register
  // being loaded and the loaded immediate value in the output parameters
  // 'reg' and 'value' respectively.
  static uword DecodeLoadWordImmediate(uword end,
                                       Register* reg,
                                       intptr_t* value);

  // Decodes a load sequence ending at 'end' (the last instruction of the
  // load sequence is the instruction before the one at end).  Returns the
  // address of the first instruction in the sequence.  Returns the register
  // being loaded and the index in the pool being read from in the output
  // parameters 'reg' and 'index' respectively.
  static uword DecodeLoadWordFromPool(uword end,
                                      Register* reg,
                                      intptr_t* index);
};


class CallPattern : public ValueObject {
 public:
  CallPattern(uword pc, const Code& code);

  RawICData* IcData();
  RawArray* ClosureArgumentsDescriptor();

  uword TargetAddress() const;
  void SetTargetAddress(uword target_address) const;

  // This constant length is only valid for inserted call patterns used for
  // lazy deoptimization. Regular call pattern may vary in length.
  static int LengthInBytes();

  static void InsertAt(uword pc, uword target_address);

 private:
  const ObjectPool& object_pool_;

  uword end_;
  uword args_desc_load_end_;
  uword ic_data_load_end_;

  intptr_t target_address_pool_index_;
  Array& args_desc_;
  ICData& ic_data_;

  DISALLOW_COPY_AND_ASSIGN(CallPattern);
};


class JumpPattern : public ValueObject {
 public:
  JumpPattern(uword pc, const Code& code);

  static const int kLengthInBytes = 3 * Instr::kInstrSize;

  static int pattern_length_in_bytes();

  bool IsValid() const;
  uword TargetAddress() const;
  void SetTargetAddress(uword target_address) const;

 private:
  const uword pc_;

  DISALLOW_COPY_AND_ASSIGN(JumpPattern);
};


class ReturnPattern : public ValueObject {
 public:
  explicit ReturnPattern(uword pc);

  // bx_lr = 1.
  static const int kLengthInBytes = 1 * Instr::kInstrSize;

  int pattern_length_in_bytes() const {
    return kLengthInBytes;
  }

  bool IsValid() const;

 private:
  const uword pc_;
};

}  // namespace dart

#endif  // VM_INSTRUCTIONS_ARM_H_