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     Module *M;
  35   public:
  36     static char ID; // Class identification, replacement for typeinfo
  37     AliasAnalysisCounter() : ModulePass(ID) {
  38       initializeAliasAnalysisCounterPass(*PassRegistry::getPassRegistry());
  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:\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       return false;
  79     }
  80
  81     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  82       AliasAnalysis::getAnalysisUsage(AU);
  83       AU.addRequired<AliasAnalysis>();
  84       AU.setPreservesAll();
  85     }
  86
  87     /// getAdjustedAnalysisPointer - This method is used when a pass implements
  88     /// an analysis interface through multiple inheritance.  If needed, it
  89     /// should override this to adjust the this pointer as needed for the
  90     /// specified pass info.
  91     virtual void *getAdjustedAnalysisPointer(AnalysisID PI) {
  92       if (PI == &AliasAnalysis::ID)
  93         return (AliasAnalysis*)this;
  94       return this;
  95     }
  96
  97     // FIXME: We could count these too...
  98     bool pointsToConstantMemory(const Location &Loc) {
  99       return getAnalysis<AliasAnalysis>().pointsToConstantMemory(Loc);
 100     }
 101
 102     // Forwarding functions: just delegate to a real AA implementation, counting
 103     // the number of responses...
 104     AliasResult alias(const Location &LocA, const Location &LocB);
 105
 106     ModRefResult getModRefInfo(ImmutableCallSite CS,
 107                                const Location &Loc);
 108     ModRefResult getModRefInfo(ImmutableCallSite CS1,
 109                                ImmutableCallSite CS2) {
 110       return AliasAnalysis::getModRefInfo(CS1,CS2);
 111     }
 112   };
 113 }
 114
 115 char AliasAnalysisCounter::ID = 0;
 116 INITIALIZE_AG_PASS(AliasAnalysisCounter, AliasAnalysis, "count-aa",
 117                    "Count Alias Analysis Query Responses", false, true, false)
 118
 119 ModulePass *llvm::createAliasAnalysisCounterPass() {
 120   return new AliasAnalysisCounter();
 121 }
 122
 123 AliasAnalysis::AliasResult
 124 AliasAnalysisCounter::alias(const Location &LocA, const Location &LocB) {
 125   AliasResult R = getAnalysis<AliasAnalysis>().alias(LocA, LocB);
 126
 127   const char *AliasString;
 128   switch (R) {
 129   default: llvm_unreachable("Unknown alias type!");
 130   case NoAlias:   No++;   AliasString = "No alias"; break;
 131   case MayAlias:  May++;  AliasString = "May alias"; break;
 132   case MustAlias: Must++; AliasString = "Must alias"; break;
 133   }
 134
 135   if (PrintAll || (PrintAllFailures && R == MayAlias)) {
 136     errs() << AliasString << ":\t";
 137     errs() << "[" << LocA.Size << "B] ";
 138     WriteAsOperand(errs(), LocA.Ptr, true, M);
 139     errs() << ", ";
 140     errs() << "[" << LocB.Size << "B] ";
 141     WriteAsOperand(errs(), LocB.Ptr, true, M);
 142     errs() << "\n";
 143   }
 144
 145   return R;
 146 }
 147
 148 AliasAnalysis::ModRefResult
 149 AliasAnalysisCounter::getModRefInfo(ImmutableCallSite CS,
 150                                     const Location &Loc) {
 151   ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, Loc);
 152
 153   const char *MRString;
 154   switch (R) {
 155   default:       llvm_unreachable("Unknown mod/ref type!");
 156   case NoModRef: NoMR++;     MRString = "NoModRef"; break;
 157   case Ref:      JustRef++;  MRString = "JustRef"; break;
 158   case Mod:      JustMod++;  MRString = "JustMod"; break;
 159   case ModRef:   MR++;       MRString = "ModRef"; break;
 160   }
 161
 162   if (PrintAll || (PrintAllFailures && R == ModRef)) {
 163     errs() << MRString << ":  Ptr: ";
 164     errs() << "[" << Loc.Size << "B] ";
 165     WriteAsOperand(errs(), Loc.Ptr, true, M);
 166     errs() << "\t<->" << *CS.getInstruction() << '\n';
 167   }
 168   return R;
 169 }