ARMUnwindOpAsm.h revision 360784 
1//===-- ARMUnwindOpAsm.h - ARM Unwind Opcodes Assembler ---------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares the unwind opcode assembler for ARM exception handling
10// table.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
15#define LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
16
17#include "llvm/ADT/SmallVector.h"
18#include <cstddef>
19#include <cstdint>
20
21namespace llvm {
22
23class MCSymbol;
24
25class UnwindOpcodeAssembler {
26private:
27  SmallVector<uint8_t, 32> Ops;
28  SmallVector<unsigned, 8> OpBegins;
29  bool HasPersonality = false;
30
31public:
32  UnwindOpcodeAssembler() {
33    OpBegins.push_back(0);
34  }
35
36  /// Reset the unwind opcode assembler.
37  void Reset() {
38    Ops.clear();
39    OpBegins.clear();
40    OpBegins.push_back(0);
41    HasPersonality = false;
42  }
43
44  /// Set the personality
45  void setPersonality(const MCSymbol *Per) {
46    HasPersonality = true;
47  }
48
49  /// Emit unwind opcodes for .save directives
50  void EmitRegSave(uint32_t RegSave);
51
52  /// Emit unwind opcodes for .vsave directives
53  void EmitVFPRegSave(uint32_t VFPRegSave);
54
55  /// Emit unwind opcodes to copy address from source register to $sp.
56  void EmitSetSP(uint16_t Reg);
57
58  /// Emit unwind opcodes to add $sp with an offset.
59  void EmitSPOffset(int64_t Offset);
60
61  /// Emit unwind raw opcodes
62  void EmitRaw(const SmallVectorImpl<uint8_t> &Opcodes) {
63    Ops.insert(Ops.end(), Opcodes.begin(), Opcodes.end());
64    OpBegins.push_back(OpBegins.back() + Opcodes.size());
65  }
66
67  /// Finalize the unwind opcode sequence for EmitBytes()
68  void Finalize(unsigned &PersonalityIndex,
69                SmallVectorImpl<uint8_t> &Result);
70
71private:
72  void EmitInt8(unsigned Opcode) {
73    Ops.push_back(Opcode & 0xff);
74    OpBegins.push_back(OpBegins.back() + 1);
75  }
76
77  void EmitInt16(unsigned Opcode) {
78    Ops.push_back((Opcode >> 8) & 0xff);
79    Ops.push_back(Opcode & 0xff);
80    OpBegins.push_back(OpBegins.back() + 2);
81  }
82
83  void EmitBytes(const uint8_t *Opcode, size_t Size) {
84    Ops.insert(Ops.end(), Opcode, Opcode + Size);
85    OpBegins.push_back(OpBegins.back() + Size);
86  }
87};
88
89} // end namespace llvm
90
91#endif // LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
92