1 //===--- llvm/CodeGen/WasmEHFuncInfo.h --------------------------*- 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 // Data structures for Wasm exception handling schemes.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CODEGEN_WASMEHFUNCINFO_H
14 #define LLVM_CODEGEN_WASMEHFUNCINFO_H
15 
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/PointerUnion.h"
18 
19 namespace llvm {
20 
21 class BasicBlock;
22 class Function;
23 class MachineBasicBlock;
24 
25 namespace WebAssembly {
26 enum EventTag { CPP_EXCEPTION = 0, C_LONGJMP = 1 };
27 }
28 
29 using BBOrMBB = PointerUnion<const BasicBlock *, MachineBasicBlock *>;
30 
31 struct WasmEHFuncInfo {
32   // When there is an entry <A, B>, if an exception is not caught by A, it
33   // should next unwind to the EH pad B.
34   DenseMap<BBOrMBB, BBOrMBB> EHPadUnwindMap;
35 
36   // Helper functions
37   const BasicBlock *getEHPadUnwindDest(const BasicBlock *BB) const {
38     return EHPadUnwindMap.lookup(BB).get<const BasicBlock *>();
39   }
40   void setEHPadUnwindDest(const BasicBlock *BB, const BasicBlock *Dest) {
41     EHPadUnwindMap[BB] = Dest;
42   }
43   bool hasEHPadUnwindDest(const BasicBlock *BB) const {
44     return EHPadUnwindMap.count(BB);
45   }
46 
47   MachineBasicBlock *getEHPadUnwindDest(MachineBasicBlock *MBB) const {
48     return EHPadUnwindMap.lookup(MBB).get<MachineBasicBlock *>();
49   }
50   void setEHPadUnwindDest(MachineBasicBlock *MBB, MachineBasicBlock *Dest) {
51     EHPadUnwindMap[MBB] = Dest;
52   }
53   bool hasEHPadUnwindDest(MachineBasicBlock *MBB) const {
54     return EHPadUnwindMap.count(MBB);
55   }
56 };
57 
58 // Analyze the IR in the given function to build WasmEHFuncInfo.
59 void calculateWasmEHInfo(const Function *F, WasmEHFuncInfo &EHInfo);
60 
61 } // namespace llvm
62 
63 #endif // LLVM_CODEGEN_WASMEHFUNCINFO_H
64