1//===- MCWinEH.h - Windows Unwinding Support --------------------*- 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#ifndef LLVM_MC_MCWINEH_H
10#define LLVM_MC_MCWINEH_H
11
12#include "llvm/ADT/MapVector.h"
13#include <vector>
14
15namespace llvm {
16class MCSection;
17class MCStreamer;
18class MCSymbol;
19
20namespace WinEH {
21struct Instruction {
22 const MCSymbol *Label;
23 unsigned Offset;
24 unsigned Register;
25 unsigned Operation;
26
27 Instruction(unsigned Op, MCSymbol *L, unsigned Reg, unsigned Off)
28 : Label(L), Offset(Off), Register(Reg), Operation(Op) {}
29
30 bool operator==(const Instruction &I) const {
31 // Check whether two instructions refer to the same operation
32 // applied at a different spot (i.e. pointing at a different label).
33 return Offset == I.Offset && Register == I.Register &&
34 Operation == I.Operation;
35 }
36 bool operator!=(const Instruction &I) const { return !(*this == I); }
37};
38
39struct FrameInfo {
40 const MCSymbol *Begin = nullptr;
41 const MCSymbol *End = nullptr;
42 const MCSymbol *FuncletOrFuncEnd = nullptr;
43 const MCSymbol *ExceptionHandler = nullptr;
44 const MCSymbol *Function = nullptr;
45 const MCSymbol *PrologEnd = nullptr;
46 const MCSymbol *Symbol = nullptr;
47 MCSection *TextSection = nullptr;
48 uint32_t PackedInfo = 0;
49 uint32_t PrologCodeBytes = 0;
50
51 bool HandlesUnwind = false;
52 bool HandlesExceptions = false;
53 bool EmitAttempted = false;
54 bool Fragment = false;
55
56 int LastFrameInst = -1;
57 const FrameInfo *ChainedParent = nullptr;
58 std::vector<Instruction> Instructions;
59 struct Epilog {
60 std::vector<Instruction> Instructions;
61 unsigned Condition;
62 MCSymbol *End;
63 };
64 MapVector<MCSymbol *, Epilog> EpilogMap;
65
66 // For splitting unwind info of large functions
67 struct Segment {
68 int64_t Offset;
69 int64_t Length;
70 bool HasProlog;
71 MCSymbol *Symbol = nullptr;
72 // Map an Epilog's symbol to its offset within the function.
73 MapVector<MCSymbol *, int64_t> Epilogs;
74
75 Segment(int64_t Offset, int64_t Length, bool HasProlog = false)
76 : Offset(Offset), Length(Length), HasProlog(HasProlog) {}
77 };
78
79 std::vector<Segment> Segments;
80
81 FrameInfo() = default;
82 FrameInfo(const MCSymbol *Function, const MCSymbol *BeginFuncEHLabel)
83 : Begin(BeginFuncEHLabel), Function(Function) {}
84 FrameInfo(const MCSymbol *Function, const MCSymbol *BeginFuncEHLabel,
85 const FrameInfo *ChainedParent)
86 : Begin(BeginFuncEHLabel), Function(Function),
87 ChainedParent(ChainedParent) {}
88
89 bool empty() const {
90 if (!Instructions.empty())
91 return false;
92 for (const auto &E : EpilogMap)
93 if (!E.second.Instructions.empty())
94 return false;
95 return true;
96 }
97};
98
99class UnwindEmitter {
100public:
101 virtual ~UnwindEmitter();
102
103 /// This emits the unwind info sections (.pdata and .xdata in PE/COFF).
104 virtual void Emit(MCStreamer &Streamer) const = 0;
105 virtual void EmitUnwindInfo(MCStreamer &Streamer, FrameInfo *FI,
106 bool HandlerData) const = 0;
107};
108}
109}
110
111#endif
112

source code of llvm/include/llvm/MC/MCWinEH.h