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 | |
15 | namespace llvm { |
16 | class MCSection; |
17 | class MCStreamer; |
18 | class MCSymbol; |
19 | |
20 | namespace WinEH { |
21 | struct 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 | |
39 | struct 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 | |
99 | class UnwindEmitter { |
100 | public: |
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 | |