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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 #include "llvm/IR/Instructions.h"
22 
23 namespace llvm {
24 class AllocaInst;
25 class BasicBlock;
26 class CatchReturnInst;
27 class Constant;
28 class Function;
29 class GlobalVariable;
30 class InvokeInst;
31 class IntrinsicInst;
32 class LandingPadInst;
33 class MCExpr;
34 class MCSymbol;
35 class MachineBasicBlock;
36 class Value;
37 
38 // The following structs respresent the .xdata tables for various
39 // Windows-related EH personalities.
40 
41 typedef PointerUnion<const BasicBlock *, MachineBasicBlock *> MBBOrBasicBlock;
42 
43 struct CxxUnwindMapEntry {
44   int ToState;
45   MBBOrBasicBlock Cleanup;
46 };
47 
48 /// Similar to CxxUnwindMapEntry, but supports SEH filters.
49 struct SEHUnwindMapEntry {
50   /// If unwinding continues through this handler, transition to the handler at
51   /// this state. This indexes into SEHUnwindMap.
52   int ToState = -1;
53 
54   bool IsFinally = false;
55 
56   /// Holds the filter expression function.
57   const Function *Filter = nullptr;
58 
59   /// Holds the __except or __finally basic block.
60   MBBOrBasicBlock Handler;
61 };
62 
63 struct WinEHHandlerType {
64   int Adjectives;
65   /// The CatchObj starts out life as an LLVM alloca and is eventually turned
66   /// frame index.
67   union {
68     const AllocaInst *Alloca;
69     int FrameIndex;
70   } CatchObj = {};
71   GlobalVariable *TypeDescriptor;
72   MBBOrBasicBlock Handler;
73 };
74 
75 struct WinEHTryBlockMapEntry {
76   int TryLow = -1;
77   int TryHigh = -1;
78   int CatchHigh = -1;
79   SmallVector<WinEHHandlerType, 1> HandlerArray;
80 };
81 
82 enum class ClrHandlerType { Catch, Finally, Fault, Filter };
83 
84 struct ClrEHUnwindMapEntry {
85   MBBOrBasicBlock Handler;
86   uint32_t TypeToken;
87   int HandlerParentState; ///< Outer handler enclosing this entry's handler
88   int TryParentState; ///< Outer try region enclosing this entry's try region,
89                       ///< treating later catches on same try as "outer"
90   ClrHandlerType HandlerType;
91 };
92 
93 struct WinEHFuncInfo {
94   DenseMap<const Instruction *, int> EHPadStateMap;
95   DenseMap<const FuncletPadInst *, int> FuncletBaseStateMap;
96   DenseMap<const InvokeInst *, int> InvokeStateMap;
97   DenseMap<MCSymbol *, std::pair<int, MCSymbol *>> LabelToStateMap;
98   SmallVector<CxxUnwindMapEntry, 4> CxxUnwindMap;
99   SmallVector<WinEHTryBlockMapEntry, 4> TryBlockMap;
100   SmallVector<SEHUnwindMapEntry, 4> SEHUnwindMap;
101   SmallVector<ClrEHUnwindMapEntry, 4> ClrEHUnwindMap;
102   int UnwindHelpFrameIdx = INT_MAX;
103   int PSPSymFrameIdx = INT_MAX;
104 
getLastStateNumberWinEHFuncInfo105   int getLastStateNumber() const { return CxxUnwindMap.size() - 1; }
106 
107   void addIPToStateRange(const InvokeInst *II, MCSymbol *InvokeBegin,
108                          MCSymbol *InvokeEnd);
109 
110   int EHRegNodeFrameIndex = INT_MAX;
111   int EHRegNodeEndOffset = INT_MAX;
112   int EHGuardFrameIndex = INT_MAX;
113   int SEHSetFrameOffset = INT_MAX;
114 
115   WinEHFuncInfo();
116 };
117 
118 /// Analyze the IR in ParentFn and it's handlers to build WinEHFuncInfo, which
119 /// describes the state numbers and tables used by __CxxFrameHandler3. This
120 /// analysis assumes that WinEHPrepare has already been run.
121 void calculateWinCXXEHStateNumbers(const Function *ParentFn,
122                                    WinEHFuncInfo &FuncInfo);
123 
124 void calculateSEHStateNumbers(const Function *ParentFn,
125                               WinEHFuncInfo &FuncInfo);
126 
127 void calculateClrEHStateNumbers(const Function *Fn, WinEHFuncInfo &FuncInfo);
128 }
129 #endif // LLVM_CODEGEN_WINEHFUNCINFO_H
130