1 //===-- UnifyFunctionExitNodes.h - Ensure fn's have one return --*- 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 // This pass is used to ensure that functions have at most one return and one 11 // unwind instruction in them. Additionally, it keeps track of which node is 12 // the new exit node of the CFG. If there are no return or unwind instructions 13 // in the function, the getReturnBlock/getUnwindBlock methods will return a null 14 // pointer. 15 // 16 //===----------------------------------------------------------------------===// 17 18 #ifndef LLVM_TRANSFORMS_UNIFYFUNCTIONEXITNODES_H 19 #define LLVM_TRANSFORMS_UNIFYFUNCTIONEXITNODES_H 20 21 #include "llvm/Pass.h" 22 23 namespace llvm { 24 25 struct UnifyFunctionExitNodes : public FunctionPass { 26 BasicBlock *ReturnBlock, *UnwindBlock, *UnreachableBlock; 27 28 public: 29 static char ID; // Pass identification, replacement for typeid 30 UnifyFunctionExitNodes() : FunctionPass(ID), 31 ReturnBlock(nullptr), UnwindBlock(nullptr) { 32 initializeUnifyFunctionExitNodesPass(*PassRegistry::getPassRegistry()); 33 } 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 llvm namespace 51 52 #endif 53
