lib/Analysis/AliasAnalysisCounter.cpp

   1 //===- AliasAnalysisCounter.cpp - Alias Analysis Query Counter ------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements a pass which can be used to count how many alias queries
  11 // are being made and how the alias analysis implementation being used responds.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Analysis/Passes.h"
  16 #include "llvm/Pass.h"
  17 #include "llvm/Analysis/AliasAnalysis.h"
  18 #include "llvm/Assembly/Writer.h"
  19 #include "llvm/Support/CommandLine.h"
  20 #include <iostream>
  21 using namespace llvm;
  22
  23 namespace {
  24   cl::opt<bool>
  25   PrintAll("count-aa-print-all-queries", cl::ReallyHidden);
  26   cl::opt<bool>
  27   PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
  28
  29   class AliasAnalysisCounter : public ModulePass, public AliasAnalysis {
  30     unsigned No, May, Must;
  31     unsigned NoMR, JustRef, JustMod, MR;
  32     const char *Name;
  33     Module *M;
  34   public:
  35     AliasAnalysisCounter() {
  36       No = May = Must = 0;
  37       NoMR = JustRef = JustMod = MR = 0;
  38     }
  39
  40     void printLine(const char *Desc, unsigned Val, unsigned Sum) {
  41       std::cerr <<  "  " << Val << " " << Desc << " responses ("
  42                 << Val*100/Sum << "%)\n";
  43     }
  44     ~AliasAnalysisCounter() {
  45       unsigned AASum = No+May+Must;
  46       unsigned MRSum = NoMR+JustRef+JustMod+MR;
  47       if (AASum + MRSum) { // Print a report if any counted queries occurred...
  48         std::cerr
  49           << "\n===== Alias Analysis Counter Report =====\n"
  50           << "  Analysis counted: " << Name << "\n"
  51           << "  " << AASum << " Total Alias Queries Performed\n";
  52         if (AASum) {
  53           printLine("no alias",     No, AASum);
  54           printLine("may alias",   May, AASum);
  55           printLine("must alias", Must, AASum);
  56           std::cerr
  57             << "  Alias Analysis Counter Summary: " << No*100/AASum << "%/"
  58             << May*100/AASum << "%/" << Must*100/AASum<<"%\n\n";
  59         }
  60
  61         std::cerr
  62           << "  " << MRSum    << " Total Mod/Ref Queries Performed\n";
  63         if (MRSum) {
  64           printLine("no mod/ref",    NoMR, MRSum);
  65           printLine("ref",        JustRef, MRSum);
  66           printLine("mod",        JustMod, MRSum);
  67           printLine("mod/ref",         MR, MRSum);
  68           std::cerr
  69             << "  Mod/Ref Analysis Counter Summary: " << NoMR*100/MRSum<< "%/"
  70             << JustRef*100/MRSum << "%/" << JustMod*100/MRSum << "%/"
  71             << MR*100/MRSum <<"%\n\n";
  72         }
  73       }
  74     }
  75
  76     bool runOnModule(Module &M) {
  77       this->M = &M;
  78       InitializeAliasAnalysis(this);
  79       Name = dynamic_cast<Pass*>(&getAnalysis<AliasAnalysis>())->getPassName();
  80       return false;
  81     }
  82
  83     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  84       AliasAnalysis::getAnalysisUsage(AU);
  85       AU.addRequired<AliasAnalysis>();
  86       AU.setPreservesAll();
  87     }
  88
  89     // FIXME: We could count these too...
  90     bool pointsToConstantMemory(const Value *P) {
  91       return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
  92     }
  93     bool doesNotAccessMemory(Function *F) {
  94       return getAnalysis<AliasAnalysis>().doesNotAccessMemory(F);
  95     }
  96     bool onlyReadsMemory(Function *F) {
  97       return getAnalysis<AliasAnalysis>().onlyReadsMemory(F);
  98     }
  99
 100
 101     // Forwarding functions: just delegate to a real AA implementation, counting
 102     // the number of responses...
 103     AliasResult alias(const Value *V1, unsigned V1Size,
 104                       const Value *V2, unsigned V2Size);
 105
 106     ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
 107     ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
 108       return AliasAnalysis::getModRefInfo(CS1,CS2);
 109     }
 110   };
 111
 112   RegisterOpt<AliasAnalysisCounter>
 113   X("count-aa", "Count Alias Analysis Query Responses");
 114   RegisterAnalysisGroup<AliasAnalysis, AliasAnalysisCounter> Y;
 115 }
 116
 117 ModulePass *llvm::createAliasAnalysisCounterPass() {
 118   return new AliasAnalysisCounter();
 119 }
 120
 121 AliasAnalysis::AliasResult
 122 AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
 123                             const Value *V2, unsigned V2Size) {
 124   AliasResult R = getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
 125
 126   const char *AliasString;
 127   switch (R) {
 128   default: assert(0 && "Unknown alias type!");
 129   case NoAlias:   No++;   AliasString = "No alias"; break;
 130   case MayAlias:  May++;  AliasString = "May alias"; break;
 131   case MustAlias: Must++; AliasString = "Must alias"; break;
 132   }
 133
 134   if (PrintAll || (PrintAllFailures && R == MayAlias)) {
 135     std::cerr << AliasString << ":\t";
 136     std::cerr << "[" << V1Size << "B] ";
 137     WriteAsOperand(std::cerr, V1, true, true, M) << ", ";
 138     std::cerr << "[" << V2Size << "B] ";
 139     WriteAsOperand(std::cerr, V2, true, true, M) << "\n";
 140   }
 141
 142   return R;
 143 }
 144
 145 AliasAnalysis::ModRefResult
 146 AliasAnalysisCounter::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
 147   ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, P, Size);
 148
 149   const char *MRString;
 150   switch (R) {
 151   default:       assert(0 && "Unknown mod/ref type!");
 152   case NoModRef: NoMR++;     MRString = "NoModRef"; break;
 153   case Ref:      JustRef++;  MRString = "JustRef"; break;
 154   case Mod:      JustMod++;  MRString = "JustMod"; break;
 155   case ModRef:   MR++;       MRString = "ModRef"; break;
 156   }
 157
 158   if (PrintAll || (PrintAllFailures && R == ModRef)) {
 159     std::cerr << MRString << ":  Ptr: ";
 160     std::cerr << "[" << Size << "B] ";
 161     WriteAsOperand(std::cerr, P, true, true, M);
 162     std::cerr << "\t<->" << *CS.getInstruction();
 163   }
 164   return R;
 165 }