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/Support/CommandLine.h"
18#include "llvm/Support/raw_ostream.h"
19using namespace llvm;
20
21static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
22
23static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
24static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
25static cl::opt<bool> PrintPartialAlias("print-partial-aliases", cl::ReallyHidden);
26static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
27
28static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
29static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
30static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
31static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
32
33static cl::opt<bool> EvalAAMD("evaluate-aa-metadata", cl::ReallyHidden);
34
35static void PrintResults(AliasResult AR, bool P,
36 std::pair<const Value *, Type *> Loc1,
37 std::pair<const Value *, Type *> Loc2,
38 const Module *M) {
39 if (PrintAll || P) {
40 Type *Ty1 = Loc1.second, *Ty2 = Loc2.second;
41 unsigned AS1 = Loc1.first->getType()->getPointerAddressSpace();
42 unsigned AS2 = Loc2.first->getType()->getPointerAddressSpace();
43 std::string o1, o2;
44 {
45 raw_string_ostream os1(o1), os2(o2);
46 Loc1.first->printAsOperand(O&: os1, PrintType: false, M);
47 Loc2.first->printAsOperand(O&: os2, PrintType: false, M);
48 }
49
50 if (o2 < o1) {
51 std::swap(lhs&: o1, rhs&: o2);
52 std::swap(a&: Ty1, b&: Ty2);
53 std::swap(a&: AS1, b&: AS2);
54 // Change offset sign for the local AR, for printing only.
55 AR.swap();
56 }
57 errs() << " " << AR << ":\t";
58 Ty1->print(O&: errs(), IsForDebug: false, /* NoDetails */ true);
59 if (AS1 != 0)
60 errs() << " addrspace(" << AS1 << ")";
61 errs() << "* " << o1 << ", ";
62 Ty2->print(O&: errs(), IsForDebug: false, /* NoDetails */ true);
63 if (AS2 != 0)
64 errs() << " addrspace(" << AS2 << ")";
65 errs() << "* " << o2 << "\n";
66 }
67}
68
69static inline void PrintModRefResults(
70 const char *Msg, bool P, Instruction *I,
71 std::pair<const Value *, Type *> Loc, Module *M) {
72 if (PrintAll || P) {
73 errs() << " " << Msg << ": Ptr: ";
74 Loc.second->print(O&: errs(), IsForDebug: false, /* NoDetails */ true);
75 errs() << "* ";
76 Loc.first->printAsOperand(O&: errs(), PrintType: false, M);
77 errs() << "\t<->" << *I << '\n';
78 }
79}
80
81static inline void PrintModRefResults(const char *Msg, bool P, CallBase *CallA,
82 CallBase *CallB, Module *M) {
83 if (PrintAll || P) {
84 errs() << " " << Msg << ": " << *CallA << " <-> " << *CallB << '\n';
85 }
86}
87
88static inline void PrintLoadStoreResults(AliasResult AR, bool P,
89 const Value *V1, const Value *V2,
90 const Module *M) {
91 if (PrintAll || P) {
92 errs() << " " << AR << ": " << *V1 << " <-> " << *V2 << '\n';
93 }
94}
95
96PreservedAnalyses AAEvaluator::run(Function &F, FunctionAnalysisManager &AM) {
97 runInternal(F, AA&: AM.getResult<AAManager>(IR&: F));
98 return PreservedAnalyses::all();
99}
100
101void AAEvaluator::runInternal(Function &F, AAResults &AA) {
102 const DataLayout &DL = F.getDataLayout();
103
104 ++FunctionCount;
105
106 SetVector<std::pair<const Value *, Type *>> Pointers;
107 SmallSetVector<CallBase *, 16> Calls;
108 SetVector<Value *> Loads;
109 SetVector<Value *> Stores;
110
111 for (Instruction &Inst : instructions(F)) {
112 if (auto *LI = dyn_cast<LoadInst>(Val: &Inst)) {
113 Pointers.insert(X: {LI->getPointerOperand(), LI->getType()});
114 Loads.insert(X: LI);
115 } else if (auto *SI = dyn_cast<StoreInst>(Val: &Inst)) {
116 Pointers.insert(X: {SI->getPointerOperand(),
117 SI->getValueOperand()->getType()});
118 Stores.insert(X: SI);
119 } else if (auto *CB = dyn_cast<CallBase>(Val: &Inst))
120 Calls.insert(X: CB);
121 }
122
123 if (PrintAll || PrintNoAlias || PrintMayAlias || PrintPartialAlias ||
124 PrintMustAlias || PrintNoModRef || PrintMod || PrintRef || PrintModRef)
125 errs() << "Function: " << F.getName() << ": " << Pointers.size()
126 << " pointers, " << Calls.size() << " call sites\n";
127
128 // iterate over the worklist, and run the full (n^2)/2 disambiguations
129 for (auto I1 = Pointers.begin(), E = Pointers.end(); I1 != E; ++I1) {
130 LocationSize Size1 = LocationSize::precise(Value: DL.getTypeStoreSize(Ty: I1->second));
131 for (auto I2 = Pointers.begin(); I2 != I1; ++I2) {
132 LocationSize Size2 =
133 LocationSize::precise(Value: DL.getTypeStoreSize(Ty: I2->second));
134 AliasResult AR = AA.alias(V1: I1->first, V1Size: Size1, V2: I2->first, V2Size: Size2);
135 switch (AR) {
136 case AliasResult::NoAlias:
137 PrintResults(AR, P: PrintNoAlias, Loc1: *I1, Loc2: *I2, M: F.getParent());
138 ++NoAliasCount;
139 break;
140 case AliasResult::MayAlias:
141 PrintResults(AR, P: PrintMayAlias, Loc1: *I1, Loc2: *I2, M: F.getParent());
142 ++MayAliasCount;
143 break;
144 case AliasResult::PartialAlias:
145 PrintResults(AR, P: PrintPartialAlias, Loc1: *I1, Loc2: *I2, M: F.getParent());
146 ++PartialAliasCount;
147 break;
148 case AliasResult::MustAlias:
149 PrintResults(AR, P: PrintMustAlias, Loc1: *I1, Loc2: *I2, M: F.getParent());
150 ++MustAliasCount;
151 break;
152 }
153 }
154 }
155
156 if (EvalAAMD) {
157 // iterate over all pairs of load, store
158 for (Value *Load : Loads) {
159 for (Value *Store : Stores) {
160 AliasResult AR = AA.alias(LocA: MemoryLocation::get(LI: cast<LoadInst>(Val: Load)),
161 LocB: MemoryLocation::get(SI: cast<StoreInst>(Val: Store)));
162 switch (AR) {
163 case AliasResult::NoAlias:
164 PrintLoadStoreResults(AR, P: PrintNoAlias, V1: Load, V2: Store, M: F.getParent());
165 ++NoAliasCount;
166 break;
167 case AliasResult::MayAlias:
168 PrintLoadStoreResults(AR, P: PrintMayAlias, V1: Load, V2: Store, M: F.getParent());
169 ++MayAliasCount;
170 break;
171 case AliasResult::PartialAlias:
172 PrintLoadStoreResults(AR, P: PrintPartialAlias, V1: Load, V2: Store, M: F.getParent());
173 ++PartialAliasCount;
174 break;
175 case AliasResult::MustAlias:
176 PrintLoadStoreResults(AR, P: PrintMustAlias, V1: Load, V2: Store, M: F.getParent());
177 ++MustAliasCount;
178 break;
179 }
180 }
181 }
182
183 // iterate over all pairs of store, store
184 for (SetVector<Value *>::iterator I1 = Stores.begin(), E = Stores.end();
185 I1 != E; ++I1) {
186 for (SetVector<Value *>::iterator I2 = Stores.begin(); I2 != I1; ++I2) {
187 AliasResult AR = AA.alias(LocA: MemoryLocation::get(SI: cast<StoreInst>(Val: *I1)),
188 LocB: MemoryLocation::get(SI: cast<StoreInst>(Val: *I2)));
189 switch (AR) {
190 case AliasResult::NoAlias:
191 PrintLoadStoreResults(AR, P: PrintNoAlias, V1: *I1, V2: *I2, M: F.getParent());
192 ++NoAliasCount;
193 break;
194 case AliasResult::MayAlias:
195 PrintLoadStoreResults(AR, P: PrintMayAlias, V1: *I1, V2: *I2, M: F.getParent());
196 ++MayAliasCount;
197 break;
198 case AliasResult::PartialAlias:
199 PrintLoadStoreResults(AR, P: PrintPartialAlias, V1: *I1, V2: *I2, M: F.getParent());
200 ++PartialAliasCount;
201 break;
202 case AliasResult::MustAlias:
203 PrintLoadStoreResults(AR, P: PrintMustAlias, V1: *I1, V2: *I2, M: F.getParent());
204 ++MustAliasCount;
205 break;
206 }
207 }
208 }
209 }
210
211 // Mod/ref alias analysis: compare all pairs of calls and values
212 for (CallBase *Call : Calls) {
213 for (const auto &Pointer : Pointers) {
214 LocationSize Size =
215 LocationSize::precise(Value: DL.getTypeStoreSize(Ty: Pointer.second));
216 switch (AA.getModRefInfo(I: Call, P: Pointer.first, Size)) {
217 case ModRefInfo::NoModRef:
218 PrintModRefResults(Msg: "NoModRef", P: PrintNoModRef, I: Call, Loc: Pointer,
219 M: F.getParent());
220 ++NoModRefCount;
221 break;
222 case ModRefInfo::Mod:
223 PrintModRefResults(Msg: "Just Mod", P: PrintMod, I: Call, Loc: Pointer, M: F.getParent());
224 ++ModCount;
225 break;
226 case ModRefInfo::Ref:
227 PrintModRefResults(Msg: "Just Ref", P: PrintRef, I: Call, Loc: Pointer, M: F.getParent());
228 ++RefCount;
229 break;
230 case ModRefInfo::ModRef:
231 PrintModRefResults(Msg: "Both ModRef", P: PrintModRef, I: Call, Loc: Pointer,
232 M: F.getParent());
233 ++ModRefCount;
234 break;
235 }
236 }
237 }
238
239 // Mod/ref alias analysis: compare all pairs of calls
240 for (CallBase *CallA : Calls) {
241 for (CallBase *CallB : Calls) {
242 if (CallA == CallB)
243 continue;
244 switch (AA.getModRefInfo(I: CallA, Call: CallB)) {
245 case ModRefInfo::NoModRef:
246 PrintModRefResults(Msg: "NoModRef", P: PrintNoModRef, CallA, CallB,
247 M: F.getParent());
248 ++NoModRefCount;
249 break;
250 case ModRefInfo::Mod:
251 PrintModRefResults(Msg: "Just Mod", P: PrintMod, CallA, CallB, M: F.getParent());
252 ++ModCount;
253 break;
254 case ModRefInfo::Ref:
255 PrintModRefResults(Msg: "Just Ref", P: PrintRef, CallA, CallB, M: F.getParent());
256 ++RefCount;
257 break;
258 case ModRefInfo::ModRef:
259 PrintModRefResults(Msg: "Both ModRef", P: PrintModRef, CallA, CallB,
260 M: F.getParent());
261 ++ModRefCount;
262 break;
263 }
264 }
265 }
266}
267
268static void PrintPercent(int64_t Num, int64_t Sum) {
269 errs() << "(" << Num * 100LL / Sum << "." << ((Num * 1000LL / Sum) % 10)
270 << "%)\n";
271}
272
273AAEvaluator::~AAEvaluator() {
274 if (FunctionCount == 0)
275 return;
276
277 int64_t AliasSum =
278 NoAliasCount + MayAliasCount + PartialAliasCount + MustAliasCount;
279 errs() << "===== Alias Analysis Evaluator Report =====\n";
280 if (AliasSum == 0) {
281 errs() << " Alias Analysis Evaluator Summary: No pointers!\n";
282 } else {
283 errs() << " " << AliasSum << " Total Alias Queries Performed\n";
284 errs() << " " << NoAliasCount << " no alias responses ";
285 PrintPercent(Num: NoAliasCount, Sum: AliasSum);
286 errs() << " " << MayAliasCount << " may alias responses ";
287 PrintPercent(Num: MayAliasCount, Sum: AliasSum);
288 errs() << " " << PartialAliasCount << " partial alias responses ";
289 PrintPercent(Num: PartialAliasCount, Sum: AliasSum);
290 errs() << " " << MustAliasCount << " must alias responses ";
291 PrintPercent(Num: MustAliasCount, Sum: AliasSum);
292 errs() << " Alias Analysis Evaluator Pointer Alias Summary: "
293 << NoAliasCount * 100 / AliasSum << "%/"
294 << MayAliasCount * 100 / AliasSum << "%/"
295 << PartialAliasCount * 100 / AliasSum << "%/"
296 << MustAliasCount * 100 / AliasSum << "%\n";
297 }
298
299 // Display the summary for mod/ref analysis
300 int64_t ModRefSum = NoModRefCount + RefCount + ModCount + ModRefCount;
301 if (ModRefSum == 0) {
302 errs() << " Alias Analysis Mod/Ref Evaluator Summary: no "
303 "mod/ref!\n";
304 } else {
305 errs() << " " << ModRefSum << " Total ModRef Queries Performed\n";
306 errs() << " " << NoModRefCount << " no mod/ref responses ";
307 PrintPercent(Num: NoModRefCount, Sum: ModRefSum);
308 errs() << " " << ModCount << " mod responses ";
309 PrintPercent(Num: ModCount, Sum: ModRefSum);
310 errs() << " " << RefCount << " ref responses ";
311 PrintPercent(Num: RefCount, Sum: ModRefSum);
312 errs() << " " << ModRefCount << " mod & ref responses ";
313 PrintPercent(Num: ModRefCount, Sum: ModRefSum);
314 errs() << " Alias Analysis Evaluator Mod/Ref Summary: "
315 << NoModRefCount * 100 / ModRefSum << "%/"
316 << ModCount * 100 / ModRefSum << "%/" << RefCount * 100 / ModRefSum
317 << "%/" << ModRefCount * 100 / ModRefSum << "%\n";
318 }
319}
320