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 22 namespace llvm { 23 24 class BasicBlock; 25 26 struct UnifyFunctionExitNodes : public FunctionPass { 27 BasicBlock *ReturnBlock = nullptr; 28 BasicBlock *UnwindBlock = nullptr; 29 BasicBlock *UnreachableBlock; 30 31 public: 32 static char ID; // Pass identification, replacement for typeid 33 UnifyFunctionExitNodes(); 34 35 // We can preserve non-critical-edgeness when we unify function exit nodes 36 void getAnalysisUsage(AnalysisUsage &AU) const override; 37 38 // getReturn|Unwind|UnreachableBlock - Return the new single (or nonexistent) 39 // return, unwind, or unreachable basic blocks in the CFG. 40 // 41 BasicBlock *getReturnBlock() const { return ReturnBlock; } 42 BasicBlock *getUnwindBlock() const { return UnwindBlock; } 43 BasicBlock *getUnreachableBlock() const { return UnreachableBlock; } 44 45 bool runOnFunction(Function &F) override; 46 }; 47 48 Pass *createUnifyFunctionExitNodesPass(); 49 50 } // end namespace llvm 51 52 #endif // LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H 53