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/Debug.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 AliasAnalysisCounter : 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(&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       errs() <<  "  " << 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         errs() << "\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           errs() << "  Alias Analysis Counter Summary: " << No*100/AASum << "%/"
  59                  << May*100/AASum << "%/" << Must*100/AASum<<"%\n\n";
  60         }
  61
  62         errs() << "  " << 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           errs() << "  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
  93     // Forwarding functions: just delegate to a real AA implementation, counting
  94     // the number of responses...
  95     AliasResult alias(const Value *V1, unsigned V1Size,
  96                       const Value *V2, unsigned V2Size);
  97
  98     ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
  99     ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
 100       return AliasAnalysis::getModRefInfo(CS1,CS2);
 101     }
 102   };
 103 }
 104
 105 char AliasAnalysisCounter::ID = 0;
 106 static RegisterPass<AliasAnalysisCounter>
 107 X("count-aa", "Count Alias Analysis Query Responses", false, true);
 108 static RegisterAnalysisGroup<AliasAnalysis> Y(X);
 109
 110 ModulePass *llvm::createAliasAnalysisCounterPass() {
 111   return new AliasAnalysisCounter();
 112 }
 113
 114 AliasAnalysis::AliasResult
 115 AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
 116                             const Value *V2, unsigned V2Size) {
 117   AliasResult R = getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
 118
 119   const char *AliasString;
 120   switch (R) {
 121   default: llvm_unreachable("Unknown alias type!");
 122   case NoAlias:   No++;   AliasString = "No alias"; break;
 123   case MayAlias:  May++;  AliasString = "May alias"; break;
 124   case MustAlias: Must++; AliasString = "Must alias"; break;
 125   }
 126
 127   if (PrintAll || (PrintAllFailures && R == MayAlias)) {
 128     errs() << AliasString << ":\t";
 129     errs() << "[" << V1Size << "B] ";
 130     WriteAsOperand(errs(), V1, true, M);
 131     errs() << ", ";
 132     errs() << "[" << V2Size << "B] ";
 133     WriteAsOperand(errs(), V2, true, M);
 134     errs() << "\n";
 135   }
 136
 137   return R;
 138 }
 139
 140 AliasAnalysis::ModRefResult
 141 AliasAnalysisCounter::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
 142   ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, P, Size);
 143
 144   const char *MRString;
 145   switch (R) {
 146   default:       llvm_unreachable("Unknown mod/ref type!");
 147   case NoModRef: NoMR++;     MRString = "NoModRef"; break;
 148   case Ref:      JustRef++;  MRString = "JustRef"; break;
 149   case Mod:      JustMod++;  MRString = "JustMod"; break;
 150   case ModRef:   MR++;       MRString = "ModRef"; break;
 151   }
 152
 153   if (PrintAll || (PrintAllFailures && R == ModRef)) {
 154     errs() << MRString << ":  Ptr: ";
 155     errs() << "[" << Size << "B] ";
 156     WriteAsOperand(errs(), P, true, M);
 157     errs() << "\t<->" << *CS.getInstruction();
 158   }
 159   return R;
 160 }