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_UTILS_UNIFYFUNCTIONEXITNODES_H 19 #define LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H 20 21 #include "llvm/Pass.h" 22 #include "llvm/PassRegistry.h" 23 24 namespace llvm { 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() : FunctionPass(ID) { 34 initializeUnifyFunctionExitNodesPass(*PassRegistry::getPassRegistry()); 35 } 36 37 // We can preserve non-critical-edgeness when we unify function exit nodes 38 void getAnalysisUsage(AnalysisUsage &AU) const override; 39 40 // getReturn|Unwind|UnreachableBlock - Return the new single (or nonexistent) 41 // return, unwind, or unreachable basic blocks in the CFG. 42 // 43 BasicBlock *getReturnBlock() const { return ReturnBlock; } 44 BasicBlock *getUnwindBlock() const { return UnwindBlock; } 45 BasicBlock *getUnreachableBlock() const { return UnreachableBlock; } 46 47 bool runOnFunction(Function &F) override; 48 }; 49 50 Pass *createUnifyFunctionExitNodesPass(); 51 52 } // end namespace llvm 53 54 #endif // LLVM_TRANSFORMS_UTILS_UNIFYFUNCTIONEXITNODES_H 55
