1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_LIBELFFILE_DWARF_REGISTER_H_
18 #define ART_LIBELFFILE_DWARF_REGISTER_H_
19 
20 namespace art {
21 namespace dwarf {
22 
23 // Represents DWARF register.
24 class Reg {
25  public:
Reg(int reg_num)26   explicit Reg(int reg_num) : num_(reg_num) { }
num()27   int num() const { return num_; }
28 
29   // TODO: Arm S0–S31 register mapping is obsolescent.
30   //   We should use VFP-v3/Neon D0-D31 mapping instead.
31   //   However, D0 is aliased to pair of S0 and S1, so using that
32   //   mapping we cannot easily say S0 is spilled and S1 is not.
33   //   There are ways around this in DWARF but they are complex.
34   //   It would be much simpler to always spill whole D registers.
35   //   Arm64 mapping is correct since we already do this there.
36   //   libunwind might struggle with the new mapping as well.
37 
ArmCore(int num)38   static Reg ArmCore(int num) { return Reg(num); }  // R0-R15.
ArmFp(int num)39   static Reg ArmFp(int num) { return Reg(64 + num); }  // S0–S31.
ArmDp(int num)40   static Reg ArmDp(int num) { return Reg(256 + num); }  // D0–D31.
Arm64Core(int num)41   static Reg Arm64Core(int num) { return Reg(num); }  // X0-X31.
Arm64Fp(int num)42   static Reg Arm64Fp(int num) { return Reg(64 + num); }  // V0-V31.
X86Core(int num)43   static Reg X86Core(int num) { return Reg(num); }
X86Fp(int num)44   static Reg X86Fp(int num) { return Reg(21 + num); }
X86_64Core(int num)45   static Reg X86_64Core(int num) {
46     static const int map[8] = {0, 2, 1, 3, 7, 6, 4, 5};
47     return Reg(num < 8 ? map[num] : num);
48   }
X86_64Fp(int num)49   static Reg X86_64Fp(int num) { return Reg(17 + num); }
50 
51  private:
52   int num_;
53 };
54 
55 }  // namespace dwarf
56 }  // namespace art
57 
58 #endif  // ART_LIBELFFILE_DWARF_REGISTER_H_
59