1 //===- CallGraphSCCPass.h - Pass that operates BU on call graph -*- 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 file defines the CallGraphSCCPass class, which is used for passes which 11 // are implemented as bottom-up traversals on the call graph. Because there may 12 // be cycles in the call graph, passes of this type operate on the call-graph in 13 // SCC order: that is, they process function bottom-up, except for recursive 14 // functions, which they process all at once. 15 // 16 // These passes are inherently interprocedural, and are required to keep the 17 // call graph up-to-date if they do anything which could modify it. 18 // 19 //===----------------------------------------------------------------------===// 20 21 #ifndef LLVM_ANALYSIS_CALLGRAPHSCCPASS_H 22 #define LLVM_ANALYSIS_CALLGRAPHSCCPASS_H 23 24 #include "llvm/Analysis/CallGraph.h" 25 #include "llvm/Pass.h" 26 27 namespace llvm { 28 29 class CallGraphNode; 30 class CallGraph; 31 class PMStack; 32 class CallGraphSCC; 33 34 class CallGraphSCCPass : public Pass { 35 public: CallGraphSCCPass(char & pid)36 explicit CallGraphSCCPass(char &pid) : Pass(PT_CallGraphSCC, pid) {} 37 38 /// createPrinterPass - Get a pass that prints the Module 39 /// corresponding to a CallGraph. 40 Pass *createPrinterPass(raw_ostream &O, 41 const std::string &Banner) const override; 42 43 using llvm::Pass::doInitialization; 44 using llvm::Pass::doFinalization; 45 46 /// doInitialization - This method is called before the SCC's of the program 47 /// has been processed, allowing the pass to do initialization as necessary. doInitialization(CallGraph & CG)48 virtual bool doInitialization(CallGraph &CG) { 49 return false; 50 } 51 52 /// runOnSCC - This method should be implemented by the subclass to perform 53 /// whatever action is necessary for the specified SCC. Note that 54 /// non-recursive (or only self-recursive) functions will have an SCC size of 55 /// 1, where recursive portions of the call graph will have SCC size > 1. 56 /// 57 /// SCC passes that add or delete functions to the SCC are required to update 58 /// the SCC list, otherwise stale pointers may be dereferenced. 59 /// 60 virtual bool runOnSCC(CallGraphSCC &SCC) = 0; 61 62 /// doFinalization - This method is called after the SCC's of the program has 63 /// been processed, allowing the pass to do final cleanup as necessary. doFinalization(CallGraph & CG)64 virtual bool doFinalization(CallGraph &CG) { 65 return false; 66 } 67 68 /// Assign pass manager to manager this pass 69 void assignPassManager(PMStack &PMS, PassManagerType PMT) override; 70 71 /// Return what kind of Pass Manager can manage this pass. getPotentialPassManagerType()72 PassManagerType getPotentialPassManagerType() const override { 73 return PMT_CallGraphPassManager; 74 } 75 76 /// getAnalysisUsage - For this class, we declare that we require and preserve 77 /// the call graph. If the derived class implements this method, it should 78 /// always explicitly call the implementation here. 79 void getAnalysisUsage(AnalysisUsage &Info) const override; 80 }; 81 82 /// CallGraphSCC - This is a single SCC that a CallGraphSCCPass is run on. 83 class CallGraphSCC { 84 void *Context; // The CGPassManager object that is vending this. 85 std::vector<CallGraphNode*> Nodes; 86 public: CallGraphSCC(void * context)87 CallGraphSCC(void *context) : Context(context) {} 88 initialize(CallGraphNode * const * I,CallGraphNode * const * E)89 void initialize(CallGraphNode*const*I, CallGraphNode*const*E) { 90 Nodes.assign(I, E); 91 } 92 isSingular()93 bool isSingular() const { return Nodes.size() == 1; } size()94 unsigned size() const { return Nodes.size(); } 95 96 /// ReplaceNode - This informs the SCC and the pass manager that the specified 97 /// Old node has been deleted, and New is to be used in its place. 98 void ReplaceNode(CallGraphNode *Old, CallGraphNode *New); 99 100 typedef std::vector<CallGraphNode*>::const_iterator iterator; begin()101 iterator begin() const { return Nodes.begin(); } end()102 iterator end() const { return Nodes.end(); } 103 }; 104 105 } // End llvm namespace 106 107 #endif 108