1 //===-- UnifyFunctionExitNodes.h - Ensure fn's have one return --*- 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 pass is used to ensure that functions have at most one return and one 10 // unwind instruction in them. Additionally, it keeps track of which node is 11 // the new exit node of the CFG. If there are no return or unwind instructions 12 // in the function, the getReturnBlock/getUnwindBlock methods will return a null 13 // pointer. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #ifndef LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H 18 #define LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H 19 20 #include "llvm/Pass.h" 21 #include "llvm/PassRegistry.h" 22 23 namespace llvm { 24 25 struct UnifyFunctionExitNodes : public FunctionPass { 26 BasicBlock *ReturnBlock = nullptr; 27 BasicBlock *UnwindBlock = nullptr; 28 BasicBlock *UnreachableBlock; 29 30 public: 31 static char ID; // Pass identification, replacement for typeid 32 UnifyFunctionExitNodes(); 33 34 // We can preserve non-critical-edgeness when we unify function exit nodes 35 void getAnalysisUsage(AnalysisUsage &AU) const override; 36 37 // getReturn|Unwind|UnreachableBlock - Return the new single (or nonexistent) 38 // return, unwind, or unreachable basic blocks in the CFG. 39 // getReturnBlockUnifyFunctionExitNodes40 BasicBlock *getReturnBlock() const { return ReturnBlock; } getUnwindBlockUnifyFunctionExitNodes41 BasicBlock *getUnwindBlock() const { return UnwindBlock; } getUnreachableBlockUnifyFunctionExitNodes42 BasicBlock *getUnreachableBlock() const { return UnreachableBlock; } 43 44 bool runOnFunction(Function &F) override; 45 }; 46 47 Pass *createUnifyFunctionExitNodesPass(); 48 49 } // end namespace llvm 50 51 #endif // LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H 52