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 #include <vector>
18 
19 namespace llvm {
20 class GlobalValue;
21 class MachineFunction;
22 class MCExpr;
23 class MCSection;
24 struct WinEHFuncInfo;
25 
26 class LLVM_LIBRARY_VISIBILITY WinException : public EHStreamer {
27   /// Per-function flag to indicate if personality info should be emitted.
28   bool shouldEmitPersonality = false;
29 
30   /// Per-function flag to indicate if the LSDA should be emitted.
31   bool shouldEmitLSDA = false;
32 
33   /// Per-function flag to indicate if frame moves info should be emitted.
34   bool shouldEmitMoves = false;
35 
36   /// True if this is a 64-bit target and we should use image relative offsets.
37   bool useImageRel32 = false;
38 
39   /// True if we are generating exception handling on Windows for ARM64.
40   bool isAArch64 = false;
41 
42   /// Pointer to the current funclet entry BB.
43   const MachineBasicBlock *CurrentFuncletEntry = nullptr;
44 
45   /// The section of the last funclet start.
46   MCSection *CurrentFuncletTextSection = nullptr;
47 
48   /// The list of symbols to add to the ehcont section
49   std::vector<const MCSymbol *> EHContTargets;
50 
51   void emitCSpecificHandlerTable(const MachineFunction *MF);
52 
53   void emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
54                               const MCSymbol *BeginLabel,
55                               const MCSymbol *EndLabel, int State);
56 
57   /// Emit the EH table data for 32-bit and 64-bit functions using
58   /// the __CxxFrameHandler3 personality.
59   void emitCXXFrameHandler3Table(const MachineFunction *MF);
60 
61   /// Emit the EH table data for _except_handler3 and _except_handler4
62   /// personality functions. These are only used on 32-bit and do not use CFI
63   /// tables.
64   void emitExceptHandlerTable(const MachineFunction *MF);
65 
66   void emitCLRExceptionTable(const MachineFunction *MF);
67 
68   void computeIP2StateTable(
69       const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
70       SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable);
71 
72   /// Emits the label used with llvm.eh.recoverfp, which is used by
73   /// outlined funclets.
74   void emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
75                                      StringRef FLinkageName);
76 
77   const MCExpr *create32bitRef(const MCSymbol *Value);
78   const MCExpr *create32bitRef(const GlobalValue *GV);
79   const MCExpr *getLabel(const MCSymbol *Label);
80   const MCExpr *getOffset(const MCSymbol *OffsetOf, const MCSymbol *OffsetFrom);
81   const MCExpr *getOffsetPlusOne(const MCSymbol *OffsetOf,
82                                  const MCSymbol *OffsetFrom);
83 
84   /// Gets the offset that we should use in a table for a stack object with the
85   /// given index. For targets using CFI (Win64, etc), this is relative to the
86   /// established SP at the end of the prologue. For targets without CFI (Win32
87   /// only), it is relative to the frame pointer.
88   int getFrameIndexOffset(int FrameIndex, const WinEHFuncInfo &FuncInfo);
89 
90   void endFuncletImpl();
91 public:
92   //===--------------------------------------------------------------------===//
93   // Main entry points.
94   //
95   WinException(AsmPrinter *A);
96   ~WinException() override;
97 
98   /// Emit all exception information that should come after the content.
99   void endModule() override;
100 
101   /// Gather pre-function exception information.  Assumes being emitted
102   /// immediately after the function entry point.
103   void beginFunction(const MachineFunction *MF) override;
104 
105   void markFunctionEnd() override;
106 
107   /// Gather and emit post-function exception information.
108   void endFunction(const MachineFunction *) override;
109 
110   /// Emit target-specific EH funclet machinery.
111   void beginFunclet(const MachineBasicBlock &MBB, MCSymbol *Sym) override;
112   void endFunclet() override;
113 };
114 }
115 
116 #endif
117 
118