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 23namespace llvm { 24 25struct UnifyFunctionExitNodes : public FunctionPass { 26 BasicBlock *ReturnBlock, *UnwindBlock, *UnreachableBlock; 27 28public: 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 48Pass *createUnifyFunctionExitNodesPass(); 49 50} // End llvm namespace 51 52#endif 53