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//===- AliasAnalysisCounter.cpp - Alias Analysis Query Counter ------------===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file implements a pass which can be used to count how many alias queries
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// are being made and how the alias analysis implementation being used responds.
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Passes.h"
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#include "llvm/Pass.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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PrintAll("count-aa-print-all-queries", cl::ReallyHidden, cl::init(true));
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PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
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class AliasAnalysisCounter : public ModulePass, public AliasAnalysis {
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unsigned No, May, Must;
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unsigned NoMR, JustRef, JustMod, MR;
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static char ID; // Class identification, replacement for typeinfo
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AliasAnalysisCounter() : ModulePass(&ID) {
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NoMR = JustRef = JustMod = MR = 0;
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void printLine(const char *Desc, unsigned Val, unsigned Sum) {
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errs() << " " << Val << " " << Desc << " responses ("
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<< Val*100/Sum << "%)\n";
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~AliasAnalysisCounter() {
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unsigned AASum = No+May+Must;
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unsigned MRSum = NoMR+JustRef+JustMod+MR;
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if (AASum + MRSum) { // Print a report if any counted queries occurred...
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errs() << "\n===== Alias Analysis Counter Report =====\n"
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<< " Analysis counted:\n"
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<< " " << AASum << " Total Alias Queries Performed\n";
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printLine("no alias", No, AASum);
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printLine("may alias", May, AASum);
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printLine("must alias", Must, AASum);
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errs() << " Alias Analysis Counter Summary: " << No*100/AASum << "%/"
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<< May*100/AASum << "%/" << Must*100/AASum<<"%\n\n";
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errs() << " " << MRSum << " Total Mod/Ref Queries Performed\n";
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printLine("no mod/ref", NoMR, MRSum);
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printLine("ref", JustRef, MRSum);
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printLine("mod", JustMod, MRSum);
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printLine("mod/ref", MR, MRSum);
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errs() << " Mod/Ref Analysis Counter Summary: " <<NoMR*100/MRSum
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<< "%/" << JustRef*100/MRSum << "%/" << JustMod*100/MRSum
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<< "%/" << MR*100/MRSum <<"%\n\n";
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bool runOnModule(Module &M) {
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InitializeAliasAnalysis(this);
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AliasAnalysis::getAnalysisUsage(AU);
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AU.addRequired<AliasAnalysis>();
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/// getAdjustedAnalysisPointer - This method is used when a pass implements
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/// an analysis interface through multiple inheritance. If needed, it
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/// should override this to adjust the this pointer as needed for the
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/// specified pass info.
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virtual void *getAdjustedAnalysisPointer(const PassInfo *PI) {
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if (PI->isPassID(&AliasAnalysis::ID))
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return (AliasAnalysis*)this;
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// FIXME: We could count these too...
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bool pointsToConstantMemory(const Value *P) {
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return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
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// Forwarding functions: just delegate to a real AA implementation, counting
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// the number of responses...
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AliasResult alias(const Value *V1, unsigned V1Size,
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const Value *V2, unsigned V2Size);
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ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
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ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
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return AliasAnalysis::getModRefInfo(CS1,CS2);
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char AliasAnalysisCounter::ID = 0;
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static RegisterPass<AliasAnalysisCounter>
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X("count-aa", "Count Alias Analysis Query Responses", false, true);
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static RegisterAnalysisGroup<AliasAnalysis> Y(X);
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ModulePass *llvm::createAliasAnalysisCounterPass() {
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return new AliasAnalysisCounter();
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AliasAnalysis::AliasResult
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AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
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const Value *V2, unsigned V2Size) {
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AliasResult R = getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
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const char *AliasString;
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default: llvm_unreachable("Unknown alias type!");
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case NoAlias: No++; AliasString = "No alias"; break;
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case MayAlias: May++; AliasString = "May alias"; break;
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case MustAlias: Must++; AliasString = "Must alias"; break;
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if (PrintAll || (PrintAllFailures && R == MayAlias)) {
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errs() << AliasString << ":\t";
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errs() << "[" << V1Size << "B] ";
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WriteAsOperand(errs(), V1, true, M);
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errs() << "[" << V2Size << "B] ";
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WriteAsOperand(errs(), V2, true, M);
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AliasAnalysis::ModRefResult
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AliasAnalysisCounter::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
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ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, P, Size);
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const char *MRString;
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default: llvm_unreachable("Unknown mod/ref type!");
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case NoModRef: NoMR++; MRString = "NoModRef"; break;
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case Ref: JustRef++; MRString = "JustRef"; break;
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case Mod: JustMod++; MRString = "JustMod"; break;
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case ModRef: MR++; MRString = "ModRef"; break;
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if (PrintAll || (PrintAllFailures && R == ModRef)) {
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errs() << MRString << ": Ptr: ";
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errs() << "[" << Size << "B] ";
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WriteAsOperand(errs(), P, true, M);
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errs() << "\t<->" << *CS.getInstruction() << '\n';