1 //===-- llvm/CodeGen/WinEHFuncInfo.h ----------------------------*- 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 // Data structures and associated state for Windows exception handling schemes.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CODEGEN_WINEHFUNCINFO_H
15 #define LLVM_CODEGEN_WINEHFUNCINFO_H
16 
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/PointerUnion.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/TinyPtrVector.h"
21 
22 namespace llvm {
23 class AllocaInst;
24 class BasicBlock;
25 class CatchReturnInst;
26 class Constant;
27 class Function;
28 class GlobalVariable;
29 class InvokeInst;
30 class IntrinsicInst;
31 class LandingPadInst;
32 class MCExpr;
33 class MCSymbol;
34 class MachineBasicBlock;
35 class Value;
36 
37 // The following structs respresent the .xdata tables for various
38 // Windows-related EH personalities.
39 
40 typedef PointerUnion<const BasicBlock *, MachineBasicBlock *> MBBOrBasicBlock;
41 
42 struct CxxUnwindMapEntry {
43   int ToState;
44   MBBOrBasicBlock Cleanup;
45 };
46 
47 /// Similar to CxxUnwindMapEntry, but supports SEH filters.
48 struct SEHUnwindMapEntry {
49   /// If unwinding continues through this handler, transition to the handler at
50   /// this state. This indexes into SEHUnwindMap.
51   int ToState = -1;
52 
53   bool IsFinally = false;
54 
55   /// Holds the filter expression function.
56   const Function *Filter = nullptr;
57 
58   /// Holds the __except or __finally basic block.
59   MBBOrBasicBlock Handler;
60 };
61 
62 struct WinEHHandlerType {
63   int Adjectives;
64   /// The CatchObj starts out life as an LLVM alloca and is eventually turned
65   /// frame index.
66   union {
67     const AllocaInst *Alloca;
68     int FrameIndex;
69   } CatchObj = {};
70   GlobalVariable *TypeDescriptor;
71   MBBOrBasicBlock Handler;
72 };
73 
74 struct WinEHTryBlockMapEntry {
75   int TryLow = -1;
76   int TryHigh = -1;
77   int CatchHigh = -1;
78   SmallVector<WinEHHandlerType, 1> HandlerArray;
79 };
80 
81 enum class ClrHandlerType { Catch, Finally, Fault, Filter };
82 
83 struct ClrEHUnwindMapEntry {
84   MBBOrBasicBlock Handler;
85   uint32_t TypeToken;
86   int Parent;
87   ClrHandlerType HandlerType;
88 };
89 
90 struct WinEHFuncInfo {
91   DenseMap<const Instruction *, int> EHPadStateMap;
92   DenseMap<const FuncletPadInst *, int> FuncletBaseStateMap;
93   DenseMap<const InvokeInst *, int> InvokeStateMap;
94   DenseMap<const CatchReturnInst *, const BasicBlock *>
95       CatchRetSuccessorColorMap;
96   DenseMap<MCSymbol *, std::pair<int, MCSymbol *>> LabelToStateMap;
97   SmallVector<CxxUnwindMapEntry, 4> CxxUnwindMap;
98   SmallVector<WinEHTryBlockMapEntry, 4> TryBlockMap;
99   SmallVector<SEHUnwindMapEntry, 4> SEHUnwindMap;
100   SmallVector<ClrEHUnwindMapEntry, 4> ClrEHUnwindMap;
101   int UnwindHelpFrameIdx = INT_MAX;
102   int PSPSymFrameIdx = INT_MAX;
103 
getLastStateNumberWinEHFuncInfo104   int getLastStateNumber() const { return CxxUnwindMap.size() - 1; }
105 
106   void addIPToStateRange(const InvokeInst *II, MCSymbol *InvokeBegin,
107                          MCSymbol *InvokeEnd);
108 
109   int EHRegNodeFrameIndex = INT_MAX;
110   int EHRegNodeEndOffset = INT_MAX;
111   int SEHSetFrameOffset = INT_MAX;
112 
WinEHFuncInfoWinEHFuncInfo113   WinEHFuncInfo() {}
114 };
115 
116 /// Analyze the IR in ParentFn and it's handlers to build WinEHFuncInfo, which
117 /// describes the state numbers and tables used by __CxxFrameHandler3. This
118 /// analysis assumes that WinEHPrepare has already been run.
119 void calculateWinCXXEHStateNumbers(const Function *ParentFn,
120                                    WinEHFuncInfo &FuncInfo);
121 
122 void calculateSEHStateNumbers(const Function *ParentFn,
123                               WinEHFuncInfo &FuncInfo);
124 
125 void calculateClrEHStateNumbers(const Function *Fn, WinEHFuncInfo &FuncInfo);
126 
127 void calculateCatchReturnSuccessorColors(const Function *Fn,
128                                          WinEHFuncInfo &FuncInfo);
129 }
130 #endif // LLVM_CODEGEN_WINEHFUNCINFO_H
131