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UnifyFunctionExitNodes.h

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00001 //===-- UnifyFunctionExitNodes.h - Ensure fn's have one return --*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This pass is used to ensure that functions have at most one return and one
00011 // unwind instruction in them.  Additionally, it keeps track of which node is
00012 // the new exit node of the CFG.  If there are no return or unwind instructions
00013 // in the function, the getReturnBlock/getUnwindBlock methods will return a null
00014 // pointer.
00015 //
00016 //===----------------------------------------------------------------------===//
00017 
00018 #ifndef LLVM_TRANSFORMS_UNIFYFUNCTIONEXITNODES_H
00019 #define LLVM_TRANSFORMS_UNIFYFUNCTIONEXITNODES_H
00020 
00021 #include "llvm/Pass.h"
00022 
00023 namespace llvm {
00024 
00025 struct UnifyFunctionExitNodes : public FunctionPass {
00026   BasicBlock *ReturnBlock, *UnwindBlock, *UnreachableBlock;
00027 public:
00028   UnifyFunctionExitNodes() : ReturnBlock(0), UnwindBlock(0) {}
00029 
00030   // We can preserve non-critical-edgeness when we unify function exit nodes
00031   virtual void getAnalysisUsage(AnalysisUsage &AU) const;
00032 
00033   // getReturn|Unwind|UnreachableBlock - Return the new single (or nonexistant)
00034   // return, unwind, or unreachable  basic blocks in the CFG.
00035   //
00036   BasicBlock *getReturnBlock() const { return ReturnBlock; }
00037   BasicBlock *getUnwindBlock() const { return UnwindBlock; }
00038   BasicBlock *getUnreachableBlock() const { return UnreachableBlock; }
00039 
00040   virtual bool runOnFunction(Function &F);
00041 };
00042 
00043 Pass *createUnifyFunctionExitNodesPass();
00044 
00045 } // End llvm namespace
00046 
00047 #endif