lib/Analysis/DataStructure/DataStructureStats.cpp

   1 //===- DSGraphStats.cpp - Various statistics for DS Graphs -----*- C++ -*--===//
   2 //
   3 //===----------------------------------------------------------------------===//
   4
   5 #include "llvm/Analysis/DataStructure.h"
   6 #include "llvm/Analysis/DSGraph.h"
   7 #include "llvm/Function.h"
   8 #include "llvm/iOther.h"
   9 #include "llvm/Pass.h"
  10 #include "Support/Statistic.h"
  11 #include <vector>
  12
  13 namespace {
  14   Statistic<> TotalNumCallees("totalcallees",
  15                 "Total number of callee functions at all indirect call sites");
  16   Statistic<> NumIndirectCalls("numindirect",
  17                 "Total number of indirect call sites in the program");
  18   Statistic<> NumPoolNodes("numpools",
  19                   "Number of allocation nodes that could be pool allocated");
  20
  21   class DSGraphStats: public FunctionPass {
  22     void countCallees(const Function& F, const DSGraph& tdGraph);
  23
  24   public:
  25     /// Driver functions to compute the Load/Store Dep. Graph per function.
  26     bool runOnFunction(Function& F);
  27
  28     /// getAnalysisUsage - This modify nothing, and uses the Top-Down Graph.
  29     void getAnalysisUsage(AnalysisUsage &AU) const {
  30       AU.setPreservesAll();
  31       AU.addRequired<TDDataStructures>();
  32     }
  33
  34     /// Debugging support methods
  35     void print(std::ostream &O) const { }
  36     void dump() const;
  37   };
  38
  39   static RegisterAnalysis<DSGraphStats> Z("dsstats", "DS Graph Statistics");
  40 }
  41
  42 static bool isIndirectCallee(Value *V) {
  43   if (isa<Function>(V)) return false;
  44
  45   if (CastInst *CI = dyn_cast<CastInst>(V))
  46     return isIndirectCallee(CI->getOperand(0));
  47   return true;
  48 }
  49
  50
  51 void DSGraphStats::countCallees(const Function& F,
  52                                 const DSGraph& tdGraph)
  53 {
  54   unsigned numIndirectCalls = 0, totalNumCallees = 0;
  55
  56   const std::vector<DSCallSite>& callSites = tdGraph.getFunctionCalls();
  57   for (unsigned i=0, N = callSites.size(); i < N; ++i)
  58     if (isIndirectCallee(callSites[i].getCallInst().getCalledValue()))
  59       { // This is an indirect function call
  60         std::vector<GlobalValue*> Callees =
  61           callSites[i].getCallee().getNode()->getGlobals();
  62         if (Callees.size() > 0)
  63           {
  64             totalNumCallees  += Callees.size();
  65             ++numIndirectCalls;
  66           }
  67 #ifndef NDEBUG
  68         else
  69           std::cerr << "WARNING: No callee in Function " << F.getName()
  70                       << "at call:\n" << callSites[i].getCallInst();
  71 #endif
  72       }
  73
  74   TotalNumCallees  += totalNumCallees;
  75   NumIndirectCalls += numIndirectCalls;
  76
  77   if (numIndirectCalls)
  78     std::cout << "  In function " << F.getName() << ":  "
  79               << (totalNumCallees / (double) numIndirectCalls)
  80               << " average callees per indirect call\n";
  81 }
  82
  83
  84 bool DSGraphStats::runOnFunction(Function& F)
  85 {
  86   const DSGraph& tdGraph = getAnalysis<TDDataStructures>().getDSGraph(F);
  87   countCallees(F, tdGraph);
  88   return true;
  89 }
  90
  91 void DSGraphStats::dump() const
  92 {
  93   this->print(std::cerr);
  94 }