lib/Analysis/AliasAnalysisEvaluator.cpp

   1 //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
   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 #include "llvm/Analysis/AliasAnalysisEvaluator.h"
  11 #include "llvm/ADT/SetVector.h"
  12 #include "llvm/Analysis/AliasAnalysis.h"
  13 #include "llvm/IR/Constants.h"
  14 #include "llvm/IR/DataLayout.h"
  15 #include "llvm/IR/DerivedTypes.h"
  16 #include "llvm/IR/Function.h"
  17 #include "llvm/IR/InstIterator.h"
  18 #include "llvm/IR/Instructions.h"
  19 #include "llvm/IR/Module.h"
  20 #include "llvm/Pass.h"
  21 #include "llvm/Support/CommandLine.h"
  22 #include "llvm/Support/Debug.h"
  23 #include "llvm/Support/raw_ostream.h"
  24 using namespace llvm;
  25
  26 static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
  27
  28 static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
  29 static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
  30 static cl::opt<bool> PrintPartialAlias("print-partial-aliases", cl::ReallyHidden);
  31 static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
  32
  33 static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
  34 static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
  35 static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
  36 static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
  37 static cl::opt<bool> PrintMust("print-must", cl::ReallyHidden);
  38 static cl::opt<bool> PrintMustRef("print-mustref", cl::ReallyHidden);
  39 static cl::opt<bool> PrintMustMod("print-mustmod", cl::ReallyHidden);
  40 static cl::opt<bool> PrintMustModRef("print-mustmodref", cl::ReallyHidden);
  41
  42 static cl::opt<bool> EvalAAMD("evaluate-aa-metadata", cl::ReallyHidden);
  43
  44 static void PrintResults(AliasResult AR, bool P, const Value *V1,
  45                          const Value *V2, const Module *M) {
  46   if (PrintAll || P) {
  47     std::string o1, o2;
  48     {
  49       raw_string_ostream os1(o1), os2(o2);
  50       V1->printAsOperand(os1, true, M);
  51       V2->printAsOperand(os2, true, M);
  52     }
  53
  54     if (o2 < o1)
  55       std::swap(o1, o2);
  56     errs() << "  " << AR << ":\t" << o1 << ", " << o2 << "\n";
  57   }
  58 }
  59
  60 static inline void PrintModRefResults(const char *Msg, bool P, Instruction *I,
  61                                       Value *Ptr, Module *M) {
  62   if (PrintAll || P) {
  63     errs() << "  " << Msg << ":  Ptr: ";
  64     Ptr->printAsOperand(errs(), true, M);
  65     errs() << "\t<->" << *I << '\n';
  66   }
  67 }
  68
  69 static inline void PrintModRefResults(const char *Msg, bool P, CallSite CSA,
  70                                       CallSite CSB, Module *M) {
  71   if (PrintAll || P) {
  72     errs() << "  " << Msg << ": " << *CSA.getInstruction() << " <-> "
  73            << *CSB.getInstruction() << '\n';
  74   }
  75 }
  76
  77 static inline void PrintLoadStoreResults(AliasResult AR, bool P,
  78                                          const Value *V1, const Value *V2,
  79                                          const Module *M) {
  80   if (PrintAll || P) {
  81     errs() << "  " << AR << ": " << *V1 << " <-> " << *V2 << '\n';
  82   }
  83 }
  84
  85 static inline bool isInterestingPointer(Value *V) {
  86   return V->getType()->isPointerTy()
  87       && !isa<ConstantPointerNull>(V);
  88 }
  89
  90 PreservedAnalyses AAEvaluator::run(Function &F, FunctionAnalysisManager &AM) {
  91   runInternal(F, AM.getResult<AAManager>(F));
  92   return PreservedAnalyses::all();
  93 }
  94
  95 void AAEvaluator::runInternal(Function &F, AAResults &AA) {
  96   const DataLayout &DL = F.getParent()->getDataLayout();
  97
  98   ++FunctionCount;
  99
 100   SetVector<Value *> Pointers;
 101   SmallSetVector<CallSite, 16> CallSites;
 102   SetVector<Value *> Loads;
 103   SetVector<Value *> Stores;
 104
 105   for (auto &I : F.args())
 106     if (I.getType()->isPointerTy())    // Add all pointer arguments.
 107       Pointers.insert(&I);
 108
 109   for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
 110     if (I->getType()->isPointerTy()) // Add all pointer instructions.
 111       Pointers.insert(&*I);
 112     if (EvalAAMD && isa<LoadInst>(&*I))
 113       Loads.insert(&*I);
 114     if (EvalAAMD && isa<StoreInst>(&*I))
 115       Stores.insert(&*I);
 116     Instruction &Inst = *I;
 117     if (auto CS = CallSite(&Inst)) {
 118       Value *Callee = CS.getCalledValue();
 119       // Skip actual functions for direct function calls.
 120       if (!isa<Function>(Callee) && isInterestingPointer(Callee))
 121         Pointers.insert(Callee);
 122       // Consider formals.
 123       for (Use &DataOp : CS.data_ops())
 124         if (isInterestingPointer(DataOp))
 125           Pointers.insert(DataOp);
 126       CallSites.insert(CS);
 127     } else {
 128       // Consider all operands.
 129       for (Instruction::op_iterator OI = Inst.op_begin(), OE = Inst.op_end();
 130            OI != OE; ++OI)
 131         if (isInterestingPointer(*OI))
 132           Pointers.insert(*OI);
 133     }
 134   }
 135
 136   if (PrintAll || PrintNoAlias || PrintMayAlias || PrintPartialAlias ||
 137       PrintMustAlias || PrintNoModRef || PrintMod || PrintRef || PrintModRef)
 138     errs() << "Function: " << F.getName() << ": " << Pointers.size()
 139            << " pointers, " << CallSites.size() << " call sites\n";
 140
 141   // iterate over the worklist, and run the full (n^2)/2 disambiguations
 142   for (SetVector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
 143        I1 != E; ++I1) {
 144     uint64_t I1Size = MemoryLocation::UnknownSize;
 145     Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
 146     if (I1ElTy->isSized()) I1Size = DL.getTypeStoreSize(I1ElTy);
 147
 148     for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
 149       uint64_t I2Size = MemoryLocation::UnknownSize;
 150       Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
 151       if (I2ElTy->isSized()) I2Size = DL.getTypeStoreSize(I2ElTy);
 152
 153       AliasResult AR = AA.alias(*I1, I1Size, *I2, I2Size);
 154       switch (AR) {
 155       case NoAlias:
 156         PrintResults(AR, PrintNoAlias, *I1, *I2, F.getParent());
 157         ++NoAliasCount;
 158         break;
 159       case MayAlias:
 160         PrintResults(AR, PrintMayAlias, *I1, *I2, F.getParent());
 161         ++MayAliasCount;
 162         break;
 163       case PartialAlias:
 164         PrintResults(AR, PrintPartialAlias, *I1, *I2, F.getParent());
 165         ++PartialAliasCount;
 166         break;
 167       case MustAlias:
 168         PrintResults(AR, PrintMustAlias, *I1, *I2, F.getParent());
 169         ++MustAliasCount;
 170         break;
 171       }
 172     }
 173   }
 174
 175   if (EvalAAMD) {
 176     // iterate over all pairs of load, store
 177     for (Value *Load : Loads) {
 178       for (Value *Store : Stores) {
 179         AliasResult AR = AA.alias(MemoryLocation::get(cast<LoadInst>(Load)),
 180                                   MemoryLocation::get(cast<StoreInst>(Store)));
 181         switch (AR) {
 182         case NoAlias:
 183           PrintLoadStoreResults(AR, PrintNoAlias, Load, Store, F.getParent());
 184           ++NoAliasCount;
 185           break;
 186         case MayAlias:
 187           PrintLoadStoreResults(AR, PrintMayAlias, Load, Store, F.getParent());
 188           ++MayAliasCount;
 189           break;
 190         case PartialAlias:
 191           PrintLoadStoreResults(AR, PrintPartialAlias, Load, Store, F.getParent());
 192           ++PartialAliasCount;
 193           break;
 194         case MustAlias:
 195           PrintLoadStoreResults(AR, PrintMustAlias, Load, Store, F.getParent());
 196           ++MustAliasCount;
 197           break;
 198         }
 199       }
 200     }
 201
 202     // iterate over all pairs of store, store
 203     for (SetVector<Value *>::iterator I1 = Stores.begin(), E = Stores.end();
 204          I1 != E; ++I1) {
 205       for (SetVector<Value *>::iterator I2 = Stores.begin(); I2 != I1; ++I2) {
 206         AliasResult AR = AA.alias(MemoryLocation::get(cast<StoreInst>(*I1)),
 207                                   MemoryLocation::get(cast<StoreInst>(*I2)));
 208         switch (AR) {
 209         case NoAlias:
 210           PrintLoadStoreResults(AR, PrintNoAlias, *I1, *I2, F.getParent());
 211           ++NoAliasCount;
 212           break;
 213         case MayAlias:
 214           PrintLoadStoreResults(AR, PrintMayAlias, *I1, *I2, F.getParent());
 215           ++MayAliasCount;
 216           break;
 217         case PartialAlias:
 218           PrintLoadStoreResults(AR, PrintPartialAlias, *I1, *I2, F.getParent());
 219           ++PartialAliasCount;
 220           break;
 221         case MustAlias:
 222           PrintLoadStoreResults(AR, PrintMustAlias, *I1, *I2, F.getParent());
 223           ++MustAliasCount;
 224           break;
 225         }
 226       }
 227     }
 228   }
 229
 230   // Mod/ref alias analysis: compare all pairs of calls and values
 231   for (CallSite C : CallSites) {
 232     Instruction *I = C.getInstruction();
 233
 234     for (auto Pointer : Pointers) {
 235       uint64_t Size = MemoryLocation::UnknownSize;
 236       Type *ElTy = cast<PointerType>(Pointer->getType())->getElementType();
 237       if (ElTy->isSized()) Size = DL.getTypeStoreSize(ElTy);
 238
 239       switch (AA.getModRefInfo(C, Pointer, Size)) {
 240       case ModRefInfo::NoModRef:
 241         PrintModRefResults("NoModRef", PrintNoModRef, I, Pointer,
 242                            F.getParent());
 243         ++NoModRefCount;
 244         break;
 245       case ModRefInfo::Mod:
 246         PrintModRefResults("Just Mod", PrintMod, I, Pointer, F.getParent());
 247         ++ModCount;
 248         break;
 249       case ModRefInfo::Ref:
 250         PrintModRefResults("Just Ref", PrintRef, I, Pointer, F.getParent());
 251         ++RefCount;
 252         break;
 253       case ModRefInfo::ModRef:
 254         PrintModRefResults("Both ModRef", PrintModRef, I, Pointer,
 255                            F.getParent());
 256         ++ModRefCount;
 257         break;
 258       case ModRefInfo::Must:
 259         PrintModRefResults("Must", PrintMust, I, Pointer, F.getParent());
 260         ++MustCount;
 261         break;
 262       case ModRefInfo::MustMod:
 263         PrintModRefResults("Just Mod (MustAlias)", PrintMustMod, I, Pointer,
 264                            F.getParent());
 265         ++MustModCount;
 266         break;
 267       case ModRefInfo::MustRef:
 268         PrintModRefResults("Just Ref (MustAlias)", PrintMustRef, I, Pointer,
 269                            F.getParent());
 270         ++MustRefCount;
 271         break;
 272       case ModRefInfo::MustModRef:
 273         PrintModRefResults("Both ModRef (MustAlias)", PrintMustModRef, I,
 274                            Pointer, F.getParent());
 275         ++MustModRefCount;
 276         break;
 277       }
 278     }
 279   }
 280
 281   // Mod/ref alias analysis: compare all pairs of calls
 282   for (auto C = CallSites.begin(), Ce = CallSites.end(); C != Ce; ++C) {
 283     for (auto D = CallSites.begin(); D != Ce; ++D) {
 284       if (D == C)
 285         continue;
 286       switch (AA.getModRefInfo(*C, *D)) {
 287       case ModRefInfo::NoModRef:
 288         PrintModRefResults("NoModRef", PrintNoModRef, *C, *D, F.getParent());
 289         ++NoModRefCount;
 290         break;
 291       case ModRefInfo::Mod:
 292         PrintModRefResults("Just Mod", PrintMod, *C, *D, F.getParent());
 293         ++ModCount;
 294         break;
 295       case ModRefInfo::Ref:
 296         PrintModRefResults("Just Ref", PrintRef, *C, *D, F.getParent());
 297         ++RefCount;
 298         break;
 299       case ModRefInfo::ModRef:
 300         PrintModRefResults("Both ModRef", PrintModRef, *C, *D, F.getParent());
 301         ++ModRefCount;
 302         break;
 303       case ModRefInfo::Must:
 304         PrintModRefResults("Must", PrintMust, *C, *D, F.getParent());
 305         ++MustCount;
 306         break;
 307       case ModRefInfo::MustMod:
 308         PrintModRefResults("Just Mod (MustAlias)", PrintMustMod, *C, *D,
 309                            F.getParent());
 310         ++MustModCount;
 311         break;
 312       case ModRefInfo::MustRef:
 313         PrintModRefResults("Just Ref (MustAlias)", PrintMustRef, *C, *D,
 314                            F.getParent());
 315         ++MustRefCount;
 316         break;
 317       case ModRefInfo::MustModRef:
 318         PrintModRefResults("Both ModRef (MustAlias)", PrintMustModRef, *C, *D,
 319                            F.getParent());
 320         ++MustModRefCount;
 321         break;
 322       }
 323     }
 324   }
 325 }
 326
 327 static void PrintPercent(int64_t Num, int64_t Sum) {
 328   errs() << "(" << Num * 100LL / Sum << "." << ((Num * 1000LL / Sum) % 10)
 329          << "%)\n";
 330 }
 331
 332 AAEvaluator::~AAEvaluator() {
 333   if (FunctionCount == 0)
 334     return;
 335
 336   int64_t AliasSum =
 337       NoAliasCount + MayAliasCount + PartialAliasCount + MustAliasCount;
 338   errs() << "===== Alias Analysis Evaluator Report =====\n";
 339   if (AliasSum == 0) {
 340     errs() << "  Alias Analysis Evaluator Summary: No pointers!\n";
 341   } else {
 342     errs() << "  " << AliasSum << " Total Alias Queries Performed\n";
 343     errs() << "  " << NoAliasCount << " no alias responses ";
 344     PrintPercent(NoAliasCount, AliasSum);
 345     errs() << "  " << MayAliasCount << " may alias responses ";
 346     PrintPercent(MayAliasCount, AliasSum);
 347     errs() << "  " << PartialAliasCount << " partial alias responses ";
 348     PrintPercent(PartialAliasCount, AliasSum);
 349     errs() << "  " << MustAliasCount << " must alias responses ";
 350     PrintPercent(MustAliasCount, AliasSum);
 351     errs() << "  Alias Analysis Evaluator Pointer Alias Summary: "
 352            << NoAliasCount * 100 / AliasSum << "%/"
 353            << MayAliasCount * 100 / AliasSum << "%/"
 354            << PartialAliasCount * 100 / AliasSum << "%/"
 355            << MustAliasCount * 100 / AliasSum << "%\n";
 356   }
 357
 358   // Display the summary for mod/ref analysis
 359   int64_t ModRefSum = NoModRefCount + RefCount + ModCount + ModRefCount +
 360                       MustCount + MustRefCount + MustModCount + MustModRefCount;
 361   if (ModRefSum == 0) {
 362     errs() << "  Alias Analysis Mod/Ref Evaluator Summary: no "
 363               "mod/ref!\n";
 364   } else {
 365     errs() << "  " << ModRefSum << " Total ModRef Queries Performed\n";
 366     errs() << "  " << NoModRefCount << " no mod/ref responses ";
 367     PrintPercent(NoModRefCount, ModRefSum);
 368     errs() << "  " << ModCount << " mod responses ";
 369     PrintPercent(ModCount, ModRefSum);
 370     errs() << "  " << RefCount << " ref responses ";
 371     PrintPercent(RefCount, ModRefSum);
 372     errs() << "  " << ModRefCount << " mod & ref responses ";
 373     PrintPercent(ModRefCount, ModRefSum);
 374     errs() << "  " << MustCount << " must responses ";
 375     PrintPercent(MustCount, ModRefSum);
 376     errs() << "  " << MustModCount << " must mod responses ";
 377     PrintPercent(MustModCount, ModRefSum);
 378     errs() << "  " << MustRefCount << " must ref responses ";
 379     PrintPercent(MustRefCount, ModRefSum);
 380     errs() << "  " << MustModRefCount << " must mod & ref responses ";
 381     PrintPercent(MustModRefCount, ModRefSum);
 382     errs() << "  Alias Analysis Evaluator Mod/Ref Summary: "
 383            << NoModRefCount * 100 / ModRefSum << "%/"
 384            << ModCount * 100 / ModRefSum << "%/" << RefCount * 100 / ModRefSum
 385            << "%/" << ModRefCount * 100 / ModRefSum << "%/"
 386            << MustCount * 100 / ModRefSum << "%/"
 387            << MustRefCount * 100 / ModRefSum << "%/"
 388            << MustModCount * 100 / ModRefSum << "%/"
 389            << MustModRefCount * 100 / ModRefSum << "%\n";
 390   }
 391 }
 392
 393 namespace llvm {
 394 class AAEvalLegacyPass : public FunctionPass {
 395   std::unique_ptr<AAEvaluator> P;
 396
 397 public:
 398   static char ID; // Pass identification, replacement for typeid
 399   AAEvalLegacyPass() : FunctionPass(ID) {
 400     initializeAAEvalLegacyPassPass(*PassRegistry::getPassRegistry());
 401   }
 402
 403   void getAnalysisUsage(AnalysisUsage &AU) const override {
 404     AU.addRequired<AAResultsWrapperPass>();
 405     AU.setPreservesAll();
 406   }
 407
 408   bool doInitialization(Module &M) override {
 409     P.reset(new AAEvaluator());
 410     return false;
 411   }
 412
 413   bool runOnFunction(Function &F) override {
 414     P->runInternal(F, getAnalysis<AAResultsWrapperPass>().getAAResults());
 415     return false;
 416   }
 417   bool doFinalization(Module &M) override {
 418     P.reset();
 419     return false;
 420   }
 421 };
 422 }
 423
 424 char AAEvalLegacyPass::ID = 0;
 425 INITIALIZE_PASS_BEGIN(AAEvalLegacyPass, "aa-eval",
 426                       "Exhaustive Alias Analysis Precision Evaluator", false,
 427                       true)
 428 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
 429 INITIALIZE_PASS_END(AAEvalLegacyPass, "aa-eval",
 430                     "Exhaustive Alias Analysis Precision Evaluator", false,
 431                     true)
 432
 433 FunctionPass *llvm::createAAEvalPass() { return new AAEvalLegacyPass(); }