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1 //===--- llvm/CodeGen/WasmEHFuncInfo.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 for Wasm exception handling schemes.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CODEGEN_WASMEHFUNCINFO_H
15 #define LLVM_CODEGEN_WASMEHFUNCINFO_H
16 
17 #include "llvm/ADT/PointerUnion.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/CodeGen/MachineBasicBlock.h"
20 #include "llvm/IR/BasicBlock.h"
21 
22 namespace llvm {
23 
24 using BBOrMBB = PointerUnion<const BasicBlock *, MachineBasicBlock *>;
25 
26 struct WasmEHFuncInfo {
27   // When there is an entry <A, B>, if an exception is not caught by A, it
28   // should next unwind to the EH pad B.
29   DenseMap<BBOrMBB, BBOrMBB> EHPadUnwindMap;
30   // For entry <A, B>, A is a BB with an instruction that may throw
31   // (invoke/cleanupret in LLVM IR, call/rethrow in the backend) and B is an EH
32   // pad that A unwinds to.
33   DenseMap<BBOrMBB, BBOrMBB> ThrowUnwindMap;
34 
35   // Helper functions
getEHPadUnwindDestWasmEHFuncInfo36   const BasicBlock *getEHPadUnwindDest(const BasicBlock *BB) const {
37     return EHPadUnwindMap.lookup(BB).get<const BasicBlock *>();
38   }
setEHPadUnwindDestWasmEHFuncInfo39   void setEHPadUnwindDest(const BasicBlock *BB, const BasicBlock *Dest) {
40     EHPadUnwindMap[BB] = Dest;
41   }
getThrowUnwindDestWasmEHFuncInfo42   const BasicBlock *getThrowUnwindDest(BasicBlock *BB) const {
43     return ThrowUnwindMap.lookup(BB).get<const BasicBlock *>();
44   }
setThrowUnwindDestWasmEHFuncInfo45   void setThrowUnwindDest(const BasicBlock *BB, const BasicBlock *Dest) {
46     ThrowUnwindMap[BB] = Dest;
47   }
hasEHPadUnwindDestWasmEHFuncInfo48   bool hasEHPadUnwindDest(const BasicBlock *BB) const {
49     return EHPadUnwindMap.count(BB);
50   }
hasThrowUnwindDestWasmEHFuncInfo51   bool hasThrowUnwindDest(const BasicBlock *BB) const {
52     return ThrowUnwindMap.count(BB);
53   }
54 
getEHPadUnwindDestWasmEHFuncInfo55   MachineBasicBlock *getEHPadUnwindDest(MachineBasicBlock *MBB) const {
56     return EHPadUnwindMap.lookup(MBB).get<MachineBasicBlock *>();
57   }
setEHPadUnwindDestWasmEHFuncInfo58   void setEHPadUnwindDest(MachineBasicBlock *MBB, MachineBasicBlock *Dest) {
59     EHPadUnwindMap[MBB] = Dest;
60   }
getThrowUnwindDestWasmEHFuncInfo61   MachineBasicBlock *getThrowUnwindDest(MachineBasicBlock *MBB) const {
62     return ThrowUnwindMap.lookup(MBB).get<MachineBasicBlock *>();
63   }
setThrowUnwindDestWasmEHFuncInfo64   void setThrowUnwindDest(MachineBasicBlock *MBB, MachineBasicBlock *Dest) {
65     ThrowUnwindMap[MBB] = Dest;
66   }
hasEHPadUnwindDestWasmEHFuncInfo67   bool hasEHPadUnwindDest(MachineBasicBlock *MBB) const {
68     return EHPadUnwindMap.count(MBB);
69   }
hasThrowUnwindDestWasmEHFuncInfo70   bool hasThrowUnwindDest(MachineBasicBlock *MBB) const {
71     return ThrowUnwindMap.count(MBB);
72   }
73 };
74 
75 // Analyze the IR in the given function to build WasmEHFuncInfo.
76 void calculateWasmEHInfo(const Function *F, WasmEHFuncInfo &EHInfo);
77 
78 } // namespace llvm
79 
80 #endif // LLVM_CODEGEN_WASMEHFUNCINFO_H
81