xref: /freebsd/contrib/llvm-project/llvm/lib/Analysis/AliasAnalysisEvaluator.cpp (revision 9f23cbd6cae82fd77edfad7173432fa8dccd0a95) 
1 //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Analysis/AliasAnalysisEvaluator.h"
10 #include "llvm/ADT/SetVector.h"
11 #include "llvm/Analysis/AliasAnalysis.h"
12 #include "llvm/IR/DataLayout.h"
13 #include "llvm/IR/Function.h"
14 #include "llvm/IR/InstIterator.h"
15 #include "llvm/IR/Instructions.h"
16 #include "llvm/IR/Module.h"
17 #include "llvm/InitializePasses.h"
18 #include "llvm/Pass.h"
19 #include "llvm/Support/CommandLine.h"
20 #include "llvm/Support/raw_ostream.h"
21 using namespace llvm;
22 
23 static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
24 
25 static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
26 static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
27 static cl::opt<bool> PrintPartialAlias("print-partial-aliases", cl::ReallyHidden);
28 static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
29 
30 static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
31 static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
32 static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
33 static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
34 
35 static cl::opt<bool> EvalAAMD("evaluate-aa-metadata", cl::ReallyHidden);
36 
37 static void PrintResults(AliasResult AR, bool P,
38                          std::pair<const Value *, Type *> Loc1,
39                          std::pair<const Value *, Type *> Loc2,
40                          const Module *M) {
41   if (PrintAll || P) {
42     Type *Ty1 = Loc1.second, *Ty2 = Loc2.second;
43     unsigned AS1 = Loc1.first->getType()->getPointerAddressSpace();
44     unsigned AS2 = Loc2.first->getType()->getPointerAddressSpace();
45     std::string o1, o2;
46     {
47       raw_string_ostream os1(o1), os2(o2);
48       Loc1.first->printAsOperand(os1, false, M);
49       Loc2.first->printAsOperand(os2, false, M);
50     }
51 
52     if (o2 < o1) {
53       std::swap(o1, o2);
54       std::swap(Ty1, Ty2);
55       std::swap(AS1, AS2);
56       // Change offset sign for the local AR, for printing only.
57       AR.swap();
58     }
59     errs() << "  " << AR << ":\t";
60     Ty1->print(errs(), false, /* NoDetails */ true);
61     if (AS1 != 0)
62       errs() << " addrspace(" << AS1 << ")";
63     errs() << "* " << o1 << ", ";
64     Ty2->print(errs(), false, /* NoDetails */ true);
65     if (AS2 != 0)
66       errs() << " addrspace(" << AS2 << ")";
67     errs() << "* " << o2 << "\n";
68   }
69 }
70 
71 static inline void PrintModRefResults(
72     const char *Msg, bool P, Instruction *I,
73     std::pair<const Value *, Type *> Loc, Module *M) {
74   if (PrintAll || P) {
75     errs() << "  " << Msg << ":  Ptr: ";
76     Loc.second->print(errs(), false, /* NoDetails */ true);
77     errs() << "* ";
78     Loc.first->printAsOperand(errs(), false, M);
79     errs() << "\t<->" << *I << '\n';
80   }
81 }
82 
83 static inline void PrintModRefResults(const char *Msg, bool P, CallBase *CallA,
84                                       CallBase *CallB, Module *M) {
85   if (PrintAll || P) {
86     errs() << "  " << Msg << ": " << *CallA << " <-> " << *CallB << '\n';
87   }
88 }
89 
90 static inline void PrintLoadStoreResults(AliasResult AR, bool P,
91                                          const Value *V1, const Value *V2,
92                                          const Module *M) {
93   if (PrintAll || P) {
94     errs() << "  " << AR << ": " << *V1 << " <-> " << *V2 << '\n';
95   }
96 }
97 
98 PreservedAnalyses AAEvaluator::run(Function &F, FunctionAnalysisManager &AM) {
99   runInternal(F, AM.getResult<AAManager>(F));
100   return PreservedAnalyses::all();
101 }
102 
103 void AAEvaluator::runInternal(Function &F, AAResults &AA) {
104   const DataLayout &DL = F.getParent()->getDataLayout();
105 
106   ++FunctionCount;
107 
108   SetVector<std::pair<const Value *, Type *>> Pointers;
109   SmallSetVector<CallBase *, 16> Calls;
110   SetVector<Value *> Loads;
111   SetVector<Value *> Stores;
112 
113   for (Instruction &Inst : instructions(F)) {
114     if (auto *LI = dyn_cast<LoadInst>(&Inst)) {
115       Pointers.insert({LI->getPointerOperand(), LI->getType()});
116       Loads.insert(LI);
117     } else if (auto *SI = dyn_cast<StoreInst>(&Inst)) {
118       Pointers.insert({SI->getPointerOperand(),
119                        SI->getValueOperand()->getType()});
120       Stores.insert(SI);
121     } else if (auto *CB = dyn_cast<CallBase>(&Inst))
122       Calls.insert(CB);
123   }
124 
125   if (PrintAll || PrintNoAlias || PrintMayAlias || PrintPartialAlias ||
126       PrintMustAlias || PrintNoModRef || PrintMod || PrintRef || PrintModRef)
127     errs() << "Function: " << F.getName() << ": " << Pointers.size()
128            << " pointers, " << Calls.size() << " call sites\n";
129 
130   // iterate over the worklist, and run the full (n^2)/2 disambiguations
131   for (auto I1 = Pointers.begin(), E = Pointers.end(); I1 != E; ++I1) {
132     LocationSize Size1 = LocationSize::precise(DL.getTypeStoreSize(I1->second));
133     for (auto I2 = Pointers.begin(); I2 != I1; ++I2) {
134       LocationSize Size2 =
135           LocationSize::precise(DL.getTypeStoreSize(I2->second));
136       AliasResult AR = AA.alias(I1->first, Size1, I2->first, Size2);
137       switch (AR) {
138       case AliasResult::NoAlias:
139         PrintResults(AR, PrintNoAlias, *I1, *I2, F.getParent());
140         ++NoAliasCount;
141         break;
142       case AliasResult::MayAlias:
143         PrintResults(AR, PrintMayAlias, *I1, *I2, F.getParent());
144         ++MayAliasCount;
145         break;
146       case AliasResult::PartialAlias:
147         PrintResults(AR, PrintPartialAlias, *I1, *I2, F.getParent());
148         ++PartialAliasCount;
149         break;
150       case AliasResult::MustAlias:
151         PrintResults(AR, PrintMustAlias, *I1, *I2, F.getParent());
152         ++MustAliasCount;
153         break;
154       }
155     }
156   }
157 
158   if (EvalAAMD) {
159     // iterate over all pairs of load, store
160     for (Value *Load : Loads) {
161       for (Value *Store : Stores) {
162         AliasResult AR = AA.alias(MemoryLocation::get(cast<LoadInst>(Load)),
163                                   MemoryLocation::get(cast<StoreInst>(Store)));
164         switch (AR) {
165         case AliasResult::NoAlias:
166           PrintLoadStoreResults(AR, PrintNoAlias, Load, Store, F.getParent());
167           ++NoAliasCount;
168           break;
169         case AliasResult::MayAlias:
170           PrintLoadStoreResults(AR, PrintMayAlias, Load, Store, F.getParent());
171           ++MayAliasCount;
172           break;
173         case AliasResult::PartialAlias:
174           PrintLoadStoreResults(AR, PrintPartialAlias, Load, Store, F.getParent());
175           ++PartialAliasCount;
176           break;
177         case AliasResult::MustAlias:
178           PrintLoadStoreResults(AR, PrintMustAlias, Load, Store, F.getParent());
179           ++MustAliasCount;
180           break;
181         }
182       }
183     }
184 
185     // iterate over all pairs of store, store
186     for (SetVector<Value *>::iterator I1 = Stores.begin(), E = Stores.end();
187          I1 != E; ++I1) {
188       for (SetVector<Value *>::iterator I2 = Stores.begin(); I2 != I1; ++I2) {
189         AliasResult AR = AA.alias(MemoryLocation::get(cast<StoreInst>(*I1)),
190                                   MemoryLocation::get(cast<StoreInst>(*I2)));
191         switch (AR) {
192         case AliasResult::NoAlias:
193           PrintLoadStoreResults(AR, PrintNoAlias, *I1, *I2, F.getParent());
194           ++NoAliasCount;
195           break;
196         case AliasResult::MayAlias:
197           PrintLoadStoreResults(AR, PrintMayAlias, *I1, *I2, F.getParent());
198           ++MayAliasCount;
199           break;
200         case AliasResult::PartialAlias:
201           PrintLoadStoreResults(AR, PrintPartialAlias, *I1, *I2, F.getParent());
202           ++PartialAliasCount;
203           break;
204         case AliasResult::MustAlias:
205           PrintLoadStoreResults(AR, PrintMustAlias, *I1, *I2, F.getParent());
206           ++MustAliasCount;
207           break;
208         }
209       }
210     }
211   }
212 
213   // Mod/ref alias analysis: compare all pairs of calls and values
214   for (CallBase *Call : Calls) {
215     for (const auto &Pointer : Pointers) {
216       LocationSize Size =
217           LocationSize::precise(DL.getTypeStoreSize(Pointer.second));
218       switch (AA.getModRefInfo(Call, Pointer.first, Size)) {
219       case ModRefInfo::NoModRef:
220         PrintModRefResults("NoModRef", PrintNoModRef, Call, Pointer,
221                            F.getParent());
222         ++NoModRefCount;
223         break;
224       case ModRefInfo::Mod:
225         PrintModRefResults("Just Mod", PrintMod, Call, Pointer, F.getParent());
226         ++ModCount;
227         break;
228       case ModRefInfo::Ref:
229         PrintModRefResults("Just Ref", PrintRef, Call, Pointer, F.getParent());
230         ++RefCount;
231         break;
232       case ModRefInfo::ModRef:
233         PrintModRefResults("Both ModRef", PrintModRef, Call, Pointer,
234                            F.getParent());
235         ++ModRefCount;
236         break;
237       }
238     }
239   }
240 
241   // Mod/ref alias analysis: compare all pairs of calls
242   for (CallBase *CallA : Calls) {
243     for (CallBase *CallB : Calls) {
244       if (CallA == CallB)
245         continue;
246       switch (AA.getModRefInfo(CallA, CallB)) {
247       case ModRefInfo::NoModRef:
248         PrintModRefResults("NoModRef", PrintNoModRef, CallA, CallB,
249                            F.getParent());
250         ++NoModRefCount;
251         break;
252       case ModRefInfo::Mod:
253         PrintModRefResults("Just Mod", PrintMod, CallA, CallB, F.getParent());
254         ++ModCount;
255         break;
256       case ModRefInfo::Ref:
257         PrintModRefResults("Just Ref", PrintRef, CallA, CallB, F.getParent());
258         ++RefCount;
259         break;
260       case ModRefInfo::ModRef:
261         PrintModRefResults("Both ModRef", PrintModRef, CallA, CallB,
262                            F.getParent());
263         ++ModRefCount;
264         break;
265       }
266     }
267   }
268 }
269 
270 static void PrintPercent(int64_t Num, int64_t Sum) {
271   errs() << "(" << Num * 100LL / Sum << "." << ((Num * 1000LL / Sum) % 10)
272          << "%)\n";
273 }
274 
275 AAEvaluator::~AAEvaluator() {
276   if (FunctionCount == 0)
277     return;
278 
279   int64_t AliasSum =
280       NoAliasCount + MayAliasCount + PartialAliasCount + MustAliasCount;
281   errs() << "===== Alias Analysis Evaluator Report =====\n";
282   if (AliasSum == 0) {
283     errs() << "  Alias Analysis Evaluator Summary: No pointers!\n";
284   } else {
285     errs() << "  " << AliasSum << " Total Alias Queries Performed\n";
286     errs() << "  " << NoAliasCount << " no alias responses ";
287     PrintPercent(NoAliasCount, AliasSum);
288     errs() << "  " << MayAliasCount << " may alias responses ";
289     PrintPercent(MayAliasCount, AliasSum);
290     errs() << "  " << PartialAliasCount << " partial alias responses ";
291     PrintPercent(PartialAliasCount, AliasSum);
292     errs() << "  " << MustAliasCount << " must alias responses ";
293     PrintPercent(MustAliasCount, AliasSum);
294     errs() << "  Alias Analysis Evaluator Pointer Alias Summary: "
295            << NoAliasCount * 100 / AliasSum << "%/"
296            << MayAliasCount * 100 / AliasSum << "%/"
297            << PartialAliasCount * 100 / AliasSum << "%/"
298            << MustAliasCount * 100 / AliasSum << "%\n";
299   }
300 
301   // Display the summary for mod/ref analysis
302   int64_t ModRefSum = NoModRefCount + RefCount + ModCount + ModRefCount;
303   if (ModRefSum == 0) {
304     errs() << "  Alias Analysis Mod/Ref Evaluator Summary: no "
305               "mod/ref!\n";
306   } else {
307     errs() << "  " << ModRefSum << " Total ModRef Queries Performed\n";
308     errs() << "  " << NoModRefCount << " no mod/ref responses ";
309     PrintPercent(NoModRefCount, ModRefSum);
310     errs() << "  " << ModCount << " mod responses ";
311     PrintPercent(ModCount, ModRefSum);
312     errs() << "  " << RefCount << " ref responses ";
313     PrintPercent(RefCount, ModRefSum);
314     errs() << "  " << ModRefCount << " mod & ref responses ";
315     PrintPercent(ModRefCount, ModRefSum);
316     errs() << "  Alias Analysis Evaluator Mod/Ref Summary: "
317            << NoModRefCount * 100 / ModRefSum << "%/"
318            << ModCount * 100 / ModRefSum << "%/" << RefCount * 100 / ModRefSum
319            << "%/" << ModRefCount * 100 / ModRefSum << "%\n";
320   }
321 }
322 
323 namespace llvm {
324 class AAEvalLegacyPass : public FunctionPass {
325   std::unique_ptr<AAEvaluator> P;
326 
327 public:
328   static char ID; // Pass identification, replacement for typeid
329   AAEvalLegacyPass() : FunctionPass(ID) {
330     initializeAAEvalLegacyPassPass(*PassRegistry::getPassRegistry());
331   }
332 
333   void getAnalysisUsage(AnalysisUsage &AU) const override {
334     AU.addRequired<AAResultsWrapperPass>();
335     AU.setPreservesAll();
336   }
337 
338   bool doInitialization(Module &M) override {
339     P.reset(new AAEvaluator());
340     return false;
341   }
342 
343   bool runOnFunction(Function &F) override {
344     P->runInternal(F, getAnalysis<AAResultsWrapperPass>().getAAResults());
345     return false;
346   }
347   bool doFinalization(Module &M) override {
348     P.reset();
349     return false;
350   }
351 };
352 }
353 
354 char AAEvalLegacyPass::ID = 0;
355 INITIALIZE_PASS_BEGIN(AAEvalLegacyPass, "aa-eval",
356                       "Exhaustive Alias Analysis Precision Evaluator", false,
357                       true)
358 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
359 INITIALIZE_PASS_END(AAEvalLegacyPass, "aa-eval",
360                     "Exhaustive Alias Analysis Precision Evaluator", false,
361                     true)
362 
363 FunctionPass *llvm::createAAEvalPass() { return new AAEvalLegacyPass(); }
364