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 "llvm/Support/Compiler.h"
  21 #include "llvm/Support/Streams.h"
  22 using namespace llvm;
  23
  24 namespace {
  25   cl::opt<bool>
  26   PrintAll("count-aa-print-all-queries", cl::ReallyHidden);
  27   cl::opt<bool>
  28   PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
  29
  30   class VISIBILITY_HIDDEN AliasAnalysisCounter
  31       : public ModulePass, public AliasAnalysis {
  32     unsigned No, May, Must;
  33     unsigned NoMR, JustRef, JustMod, MR;
  34     const char *Name;
  35     Module *M;
  36   public:
  37     static char ID; // Class identification, replacement for typeinfo
  38     AliasAnalysisCounter() : ModulePass((intptr_t) &ID) {
  39       No = May = Must = 0;
  40       NoMR = JustRef = JustMod = MR = 0;
  41     }
  42
  43     void printLine(const char *Desc, unsigned Val, unsigned Sum) {
  44       cerr <<  "  " << Val << " " << Desc << " responses ("
  45            << Val*100/Sum << "%)\n";
  46     }
  47     ~AliasAnalysisCounter() {
  48       unsigned AASum = No+May+Must;
  49       unsigned MRSum = NoMR+JustRef+JustMod+MR;
  50       if (AASum + MRSum) { // Print a report if any counted queries occurred...
  51         cerr << "\n===== Alias Analysis Counter Report =====\n"
  52              << "  Analysis counted: " << Name << "\n"
  53              << "  " << AASum << " Total Alias Queries Performed\n";
  54         if (AASum) {
  55           printLine("no alias",     No, AASum);
  56           printLine("may alias",   May, AASum);
  57           printLine("must alias", Must, AASum);
  58           cerr << "  Alias Analysis Counter Summary: " << No*100/AASum << "%/"
  59                << May*100/AASum << "%/" << Must*100/AASum<<"%\n\n";
  60         }
  61
  62         cerr << "  " << 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           cerr << "  Mod/Ref Analysis Counter Summary: " <<NoMR*100/MRSum<< "%/"
  69                << JustRef*100/MRSum << "%/" << JustMod*100/MRSum << "%/"
  70                << MR*100/MRSum <<"%\n\n";
  71         }
  72       }
  73     }
  74
  75     bool runOnModule(Module &M) {
  76       this->M = &M;
  77       InitializeAliasAnalysis(this);
  78       Name = dynamic_cast<Pass*>(&getAnalysis<AliasAnalysis>())->getPassName();
  79       return false;
  80     }
  81
  82     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  83       AliasAnalysis::getAnalysisUsage(AU);
  84       AU.addRequired<AliasAnalysis>();
  85       AU.setPreservesAll();
  86     }
  87
  88     // FIXME: We could count these too...
  89     bool pointsToConstantMemory(const Value *P) {
  90       return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
  91     }
  92     bool doesNotAccessMemory(Function *F) {
  93       return getAnalysis<AliasAnalysis>().doesNotAccessMemory(F);
  94     }
  95     bool onlyReadsMemory(Function *F) {
  96       return getAnalysis<AliasAnalysis>().onlyReadsMemory(F);
  97     }
  98
  99
 100     // Forwarding functions: just delegate to a real AA implementation, counting
 101     // the number of responses...
 102     AliasResult alias(const Value *V1, unsigned V1Size,
 103                       const Value *V2, unsigned V2Size);
 104
 105     ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
 106     ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
 107       return AliasAnalysis::getModRefInfo(CS1,CS2);
 108     }
 109   };
 110
 111   char AliasAnalysisCounter::ID = 0;
 112   RegisterPass<AliasAnalysisCounter>
 113   X("count-aa", "Count Alias Analysis Query Responses");
 114   RegisterAnalysisGroup<AliasAnalysis> Y(X);
 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     cerr << AliasString << ":\t";
 136     cerr << "[" << V1Size << "B] ";
 137     WriteAsOperand(*cerr.stream(), V1, true, M) << ", ";
 138     cerr << "[" << V2Size << "B] ";
 139     WriteAsOperand(*cerr.stream(), V2, 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     cerr << MRString << ":  Ptr: ";
 160     cerr << "[" << Size << "B] ";
 161     WriteAsOperand(*cerr.stream(), P, true, M);
 162     cerr << "\t<->" << *CS.getInstruction();
 163   }
 164   return R;
 165 }