1 //===-- ARMUnwindOpAsm.h - ARM Unwind Opcodes Assembler ---------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file declares the unwind opcode assmebler for ARM exception handling
11 // table.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
16 #define LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
17 
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/Support/ARMEHABI.h"
20 #include "llvm/Support/DataTypes.h"
21 
22 namespace llvm {
23 
24 class MCSymbol;
25 
26 class UnwindOpcodeAssembler {
27 private:
28   llvm::SmallVector<uint8_t, 32> Ops;
29   llvm::SmallVector<unsigned, 8> OpBegins;
30   bool HasPersonality;
31 
32 public:
UnwindOpcodeAssembler()33   UnwindOpcodeAssembler()
34       : HasPersonality(0) {
35     OpBegins.push_back(0);
36   }
37 
38   /// Reset the unwind opcode assembler.
Reset()39   void Reset() {
40     Ops.clear();
41     OpBegins.clear();
42     OpBegins.push_back(0);
43     HasPersonality = 0;
44   }
45 
46   /// Set the personality
setPersonality(const MCSymbol * Per)47   void setPersonality(const MCSymbol *Per) {
48     HasPersonality = 1;
49   }
50 
51   /// Emit unwind opcodes for .save directives
52   void EmitRegSave(uint32_t RegSave);
53 
54   /// Emit unwind opcodes for .vsave directives
55   void EmitVFPRegSave(uint32_t VFPRegSave);
56 
57   /// Emit unwind opcodes to copy address from source register to $sp.
58   void EmitSetSP(uint16_t Reg);
59 
60   /// Emit unwind opcodes to add $sp with an offset.
61   void EmitSPOffset(int64_t Offset);
62 
63   /// Emit unwind raw opcodes
EmitRaw(const SmallVectorImpl<uint8_t> & Opcodes)64   void EmitRaw(const SmallVectorImpl<uint8_t> &Opcodes) {
65     Ops.insert(Ops.end(), Opcodes.begin(), Opcodes.end());
66     OpBegins.push_back(OpBegins.back() + Opcodes.size());
67   }
68 
69   /// Finalize the unwind opcode sequence for EmitBytes()
70   void Finalize(unsigned &PersonalityIndex,
71                 SmallVectorImpl<uint8_t> &Result);
72 
73 private:
EmitInt8(unsigned Opcode)74   void EmitInt8(unsigned Opcode) {
75     Ops.push_back(Opcode & 0xff);
76     OpBegins.push_back(OpBegins.back() + 1);
77   }
78 
EmitInt16(unsigned Opcode)79   void EmitInt16(unsigned Opcode) {
80     Ops.push_back((Opcode >> 8) & 0xff);
81     Ops.push_back(Opcode & 0xff);
82     OpBegins.push_back(OpBegins.back() + 2);
83   }
84 
EmitBytes(const uint8_t * Opcode,size_t Size)85   void EmitBytes(const uint8_t *Opcode, size_t Size) {
86     Ops.insert(Ops.end(), Opcode, Opcode + Size);
87     OpBegins.push_back(OpBegins.back() + Size);
88   }
89 };
90 
91 } // namespace llvm
92 
93 #endif
94