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CallGraphSCCPass.h

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00001 //===- CallGraphSCCPass.h - Pass that operates BU on call graph -*- 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 file defines the CallGraphSCCPass class, which is used for passes which
00011 // are implemented as bottom-up traversals on the call graph.  Because there may
00012 // be cycles in the call graph, passes of this type operate on the call-graph in
00013 // SCC order: that is, they process function bottom-up, except for recursive
00014 // functions, which they process all at once.
00015 //
00016 // These passes are inherently interprocedural, and are required to keep the
00017 // call graph up-to-date if they do anything which could modify it.
00018 //
00019 //===----------------------------------------------------------------------===//
00020 
00021 #ifndef LLVM_CALL_GRAPH_SCC_PASS_H
00022 #define LLVM_CALL_GRAPH_SCC_PASS_H
00023 
00024 #include "llvm/Pass.h"
00025 
00026 namespace llvm {
00027 
00028 class CallGraphNode;
00029 class CallGraph;
00030 
00031 struct CallGraphSCCPass : public ModulePass {
00032 
00033   /// doInitialization - This method is called before the SCC's of the program
00034   /// has been processed, allowing the pass to do initialization as necessary.
00035   virtual bool doInitialization(CallGraph &CG) {
00036     return false;
00037   }
00038 
00039   /// runOnSCC - This method should be implemented by the subclass to perform
00040   /// whatever action is necessary for the specified SCC.  Note that
00041   /// non-recursive (or only self-recursive) functions will have an SCC size of
00042   /// 1, where recursive portions of the call graph will have SCC size > 1.
00043   ///
00044   virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC) = 0;
00045 
00046   /// doFinalization - This method is called after the SCC's of the program has
00047   /// been processed, allowing the pass to do final cleanup as necessary.
00048   virtual bool doFinalization(CallGraph &CG) {
00049     return false;
00050   }
00051 
00052   /// run - Run this pass, returning true if a modification was made to the
00053   /// module argument.  This is implemented in terms of the runOnSCC method.
00054   ///
00055   virtual bool runOnModule(Module &M);
00056 
00057 
00058   /// getAnalysisUsage - For this class, we declare that we require and preserve
00059   /// the call graph.  If the derived class implements this method, it should
00060   /// always explicitly call the implementation here.
00061   virtual void getAnalysisUsage(AnalysisUsage &Info) const;
00062 };
00063 
00064 } // End llvm namespace
00065 
00066 #endif