1 //===-- WinException.h - Windows Exception Handling ----------*- 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 contains support for writing windows exception info into asm files.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
14 #define LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
15 
16 #include "EHStreamer.h"
17 
18 namespace llvm {
19 class GlobalValue;
20 class MachineFunction;
21 class MCExpr;
22 class MCSection;
23 struct WinEHFuncInfo;
24 
25 class LLVM_LIBRARY_VISIBILITY WinException : public EHStreamer {
26   /// Per-function flag to indicate if personality info should be emitted.
27   bool shouldEmitPersonality = false;
28 
29   /// Per-function flag to indicate if the LSDA should be emitted.
30   bool shouldEmitLSDA = false;
31 
32   /// Per-function flag to indicate if frame moves info should be emitted.
33   bool shouldEmitMoves = false;
34 
35   /// True if this is a 64-bit target and we should use image relative offsets.
36   bool useImageRel32 = false;
37 
38   /// True if we are generating exception handling on Windows for ARM64.
39   bool isAArch64 = false;
40 
41   /// Pointer to the current funclet entry BB.
42   const MachineBasicBlock *CurrentFuncletEntry = nullptr;
43 
44   /// The section of the last funclet start.
45   MCSection *CurrentFuncletTextSection = nullptr;
46 
47   void emitCSpecificHandlerTable(const MachineFunction *MF);
48 
49   void emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
50                               const MCSymbol *BeginLabel,
51                               const MCSymbol *EndLabel, int State);
52 
53   /// Emit the EH table data for 32-bit and 64-bit functions using
54   /// the __CxxFrameHandler3 personality.
55   void emitCXXFrameHandler3Table(const MachineFunction *MF);
56 
57   /// Emit the EH table data for _except_handler3 and _except_handler4
58   /// personality functions. These are only used on 32-bit and do not use CFI
59   /// tables.
60   void emitExceptHandlerTable(const MachineFunction *MF);
61 
62   void emitCLRExceptionTable(const MachineFunction *MF);
63 
64   void computeIP2StateTable(
65       const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
66       SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable);
67 
68   /// Emits the label used with llvm.eh.recoverfp, which is used by
69   /// outlined funclets.
70   void emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
71                                      StringRef FLinkageName);
72 
73   const MCExpr *create32bitRef(const MCSymbol *Value);
74   const MCExpr *create32bitRef(const GlobalValue *GV);
75   const MCExpr *getLabel(const MCSymbol *Label);
76   const MCExpr *getOffset(const MCSymbol *OffsetOf, const MCSymbol *OffsetFrom);
77   const MCExpr *getOffsetPlusOne(const MCSymbol *OffsetOf,
78                                  const MCSymbol *OffsetFrom);
79 
80   /// Gets the offset that we should use in a table for a stack object with the
81   /// given index. For targets using CFI (Win64, etc), this is relative to the
82   /// established SP at the end of the prologue. For targets without CFI (Win32
83   /// only), it is relative to the frame pointer.
84   int getFrameIndexOffset(int FrameIndex, const WinEHFuncInfo &FuncInfo);
85 
86   void endFuncletImpl();
87 public:
88   //===--------------------------------------------------------------------===//
89   // Main entry points.
90   //
91   WinException(AsmPrinter *A);
92   ~WinException() override;
93 
94   /// Emit all exception information that should come after the content.
95   void endModule() override;
96 
97   /// Gather pre-function exception information.  Assumes being emitted
98   /// immediately after the function entry point.
99   void beginFunction(const MachineFunction *MF) override;
100 
101   void markFunctionEnd() override;
102 
103   /// Gather and emit post-function exception information.
104   void endFunction(const MachineFunction *) override;
105 
106   /// Emit target-specific EH funclet machinery.
107   void beginFunclet(const MachineBasicBlock &MBB, MCSymbol *Sym) override;
108   void endFunclet() override;
109 };
110 }
111 
112 #endif
113 
114