include/llvm/CallGraphSCCPass.h

   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_CALL_GRAPH_SCC_PASS_H
  22 #define LLVM_CALL_GRAPH_SCC_PASS_H
  23
  24 #include "llvm/Pass.h"
  25 #include "llvm/Analysis/CallGraph.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:
  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, const std::string &Banner) const;
  41
  42   /// doInitialization - This method is called before the SCC's of the program
  43   /// has been processed, allowing the pass to do initialization as necessary.
  44   virtual bool doInitialization(CallGraph &CG) {
  45     return false;
  46   }
  47
  48   /// runOnSCC - This method should be implemented by the subclass to perform
  49   /// whatever action is necessary for the specified SCC.  Note that
  50   /// non-recursive (or only self-recursive) functions will have an SCC size of
  51   /// 1, where recursive portions of the call graph will have SCC size > 1.
  52   ///
  53   /// SCC passes that add or delete functions to the SCC are required to update
  54   /// the SCC list, otherwise stale pointers may be dereferenced.
  55   ///
  56   virtual bool runOnSCC(CallGraphSCC &SCC) = 0;
  57
  58   /// doFinalization - This method is called after the SCC's of the program has
  59   /// been processed, allowing the pass to do final cleanup as necessary.
  60   virtual bool doFinalization(CallGraph &CG) {
  61     return false;
  62   }
  63
  64   /// Assign pass manager to manager this pass
  65   virtual void assignPassManager(PMStack &PMS,
  66                                  PassManagerType PMT);
  67
  68   ///  Return what kind of Pass Manager can manage this pass.
  69   virtual PassManagerType getPotentialPassManagerType() const {
  70     return PMT_CallGraphPassManager;
  71   }
  72
  73   /// getAnalysisUsage - For this class, we declare that we require and preserve
  74   /// the call graph.  If the derived class implements this method, it should
  75   /// always explicitly call the implementation here.
  76   virtual void getAnalysisUsage(AnalysisUsage &Info) const;
  77 };
  78
  79 /// CallGraphSCC - This is a single SCC that a CallGraphSCCPass is run on.
  80 class CallGraphSCC {
  81   void *Context; // The CGPassManager object that is vending this.
  82   std::vector<CallGraphNode*> Nodes;
  83 public:
  84   CallGraphSCC(void *context) : Context(context) {}
  85
  86   void initialize(CallGraphNode*const*I, CallGraphNode*const*E) {
  87     Nodes.assign(I, E);
  88   }
  89
  90   bool isSingular() const { return Nodes.size() == 1; }
  91   unsigned size() const { return Nodes.size(); }
  92
  93   /// ReplaceNode - This informs the SCC and the pass manager that the specified
  94   /// Old node has been deleted, and New is to be used in its place.
  95   void ReplaceNode(CallGraphNode *Old, CallGraphNode *New);
  96
  97   typedef std::vector<CallGraphNode*>::const_iterator iterator;
  98   iterator begin() const { return Nodes.begin(); }
  99   iterator end() const { return Nodes.end(); }
 100 };
 101
 102 } // End llvm namespace
 103
 104 #endif