lib/Analysis/AliasAnalysisCounter.cpp

   1 //===- AliasAnalysisCounter.cpp - Alias Analysis Query Counter ------------===//
   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 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/ErrorHandling.h"
  22 #include "llvm/Support/raw_ostream.h"
  23 using namespace llvm;
  24
  25 static cl::opt<bool>
  26 PrintAll("count-aa-print-all-queries", cl::ReallyHidden, cl::init(true));
  27 static cl::opt<bool>
  28 PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
  29
  30 namespace {
  31   class VISIBILITY_HIDDEN AliasAnalysisCounter
  32       : public ModulePass, public AliasAnalysis {
  33     unsigned No, May, Must;
  34     unsigned NoMR, JustRef, JustMod, MR;
  35     const char *Name;
  36     Module *M;
  37   public:
  38     static char ID; // Class identification, replacement for typeinfo
  39     AliasAnalysisCounter() : ModulePass(&ID) {
  40       No = May = Must = 0;
  41       NoMR = JustRef = JustMod = MR = 0;
  42     }
  43
  44     void printLine(const char *Desc, unsigned Val, unsigned Sum) {
  45       errs() <<  "  " << Val << " " << Desc << " responses ("
  46              << Val*100/Sum << "%)\n";
  47     }
  48     ~AliasAnalysisCounter() {
  49       unsigned AASum = No+May+Must;
  50       unsigned MRSum = NoMR+JustRef+JustMod+MR;
  51       if (AASum + MRSum) { // Print a report if any counted queries occurred...
  52         errs() << "\n===== Alias Analysis Counter Report =====\n"
  53                << "  Analysis counted: " << Name << "\n"
  54                << "  " << AASum << " Total Alias Queries Performed\n";
  55         if (AASum) {
  56           printLine("no alias",     No, AASum);
  57           printLine("may alias",   May, AASum);
  58           printLine("must alias", Must, AASum);
  59           errs() << "  Alias Analysis Counter Summary: " << No*100/AASum << "%/"
  60                  << May*100/AASum << "%/" << Must*100/AASum<<"%\n\n";
  61         }
  62
  63         errs() << "  " << MRSum    << " Total Mod/Ref Queries Performed\n";
  64         if (MRSum) {
  65           printLine("no mod/ref",    NoMR, MRSum);
  66           printLine("ref",        JustRef, MRSum);
  67           printLine("mod",        JustMod, MRSum);
  68           printLine("mod/ref",         MR, MRSum);
  69           errs() << "  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
  94     // Forwarding functions: just delegate to a real AA implementation, counting
  95     // the number of responses...
  96     AliasResult alias(const Value *V1, unsigned V1Size,
  97                       const Value *V2, unsigned V2Size);
  98
  99     ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
 100     ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
 101       return AliasAnalysis::getModRefInfo(CS1,CS2);
 102     }
 103   };
 104 }
 105
 106 char AliasAnalysisCounter::ID = 0;
 107 static RegisterPass<AliasAnalysisCounter>
 108 X("count-aa", "Count Alias Analysis Query Responses", false, true);
 109 static RegisterAnalysisGroup<AliasAnalysis> Y(X);
 110
 111 ModulePass *llvm::createAliasAnalysisCounterPass() {
 112   return new AliasAnalysisCounter();
 113 }
 114
 115 AliasAnalysis::AliasResult
 116 AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
 117                             const Value *V2, unsigned V2Size) {
 118   AliasResult R = getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
 119
 120   const char *AliasString;
 121   switch (R) {
 122   default: llvm_unreachable("Unknown alias type!");
 123   case NoAlias:   No++;   AliasString = "No alias"; break;
 124   case MayAlias:  May++;  AliasString = "May alias"; break;
 125   case MustAlias: Must++; AliasString = "Must alias"; break;
 126   }
 127
 128   if (PrintAll || (PrintAllFailures && R == MayAlias)) {
 129     errs() << AliasString << ":\t";
 130     errs() << "[" << V1Size << "B] ";
 131     WriteAsOperand(errs(), V1, true, M);
 132     errs() << ", ";
 133     errs() << "[" << V2Size << "B] ";
 134     WriteAsOperand(errs(), V2, true, M);
 135     errs() << "\n";
 136   }
 137
 138   return R;
 139 }
 140
 141 AliasAnalysis::ModRefResult
 142 AliasAnalysisCounter::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
 143   ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, P, Size);
 144
 145   const char *MRString;
 146   switch (R) {
 147   default:       llvm_unreachable("Unknown mod/ref type!");
 148   case NoModRef: NoMR++;     MRString = "NoModRef"; break;
 149   case Ref:      JustRef++;  MRString = "JustRef"; break;
 150   case Mod:      JustMod++;  MRString = "JustMod"; break;
 151   case ModRef:   MR++;       MRString = "ModRef"; break;
 152   }
 153
 154   if (PrintAll || (PrintAllFailures && R == ModRef)) {
 155     errs() << MRString << ":  Ptr: ";
 156     errs() << "[" << Size << "B] ";
 157     WriteAsOperand(errs(), P, true, M);
 158     errs() << "\t<->" << *CS.getInstruction();
 159   }
 160   return R;
 161 }