1 //===--- AliasAnalysisTest.cpp - Mixed TBAA unit tests --------------------===//
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/AliasAnalysis.h"
10 #include "llvm/ADT/SetVector.h"
11 #include "llvm/Analysis/AssumptionCache.h"
12 #include "llvm/Analysis/BasicAliasAnalysis.h"
13 #include "llvm/Analysis/TargetLibraryInfo.h"
14 #include "llvm/AsmParser/Parser.h"
15 #include "llvm/IR/Constants.h"
16 #include "llvm/IR/InstIterator.h"
17 #include "llvm/IR/Instructions.h"
18 #include "llvm/IR/LLVMContext.h"
19 #include "llvm/IR/LegacyPassManager.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/InitializePasses.h"
22 #include "llvm/Support/SourceMgr.h"
23 #include "gtest/gtest.h"
24
25 using namespace llvm;
26
27 // Set up some test passes.
28 namespace llvm {
29 void initializeAATestPassPass(PassRegistry&);
30 void initializeTestCustomAAWrapperPassPass(PassRegistry&);
31 }
32
33 namespace {
34 struct AATestPass : FunctionPass {
35 static char ID;
AATestPass__anon7f44cadb0111::AATestPass36 AATestPass() : FunctionPass(ID) {
37 initializeAATestPassPass(*PassRegistry::getPassRegistry());
38 }
39
getAnalysisUsage__anon7f44cadb0111::AATestPass40 void getAnalysisUsage(AnalysisUsage &AU) const override {
41 AU.addRequired<AAResultsWrapperPass>();
42 AU.setPreservesAll();
43 }
44
runOnFunction__anon7f44cadb0111::AATestPass45 bool runOnFunction(Function &F) override {
46 AliasAnalysis &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
47
48 SetVector<Value *> Pointers;
49 for (Argument &A : F.args())
50 if (A.getType()->isPointerTy())
51 Pointers.insert(&A);
52 for (Instruction &I : instructions(F))
53 if (I.getType()->isPointerTy())
54 Pointers.insert(&I);
55
56 for (Value *P1 : Pointers)
57 for (Value *P2 : Pointers)
58 (void)AA.alias(P1, LocationSize::unknown(), P2,
59 LocationSize::unknown());
60
61 return false;
62 }
63 };
64 }
65
66 char AATestPass::ID = 0;
67 INITIALIZE_PASS_BEGIN(AATestPass, "aa-test-pas", "Alias Analysis Test Pass",
68 false, true)
69 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
70 INITIALIZE_PASS_END(AATestPass, "aa-test-pass", "Alias Analysis Test Pass",
71 false, true)
72
73 namespace {
74 /// A test customizable AA result. It merely accepts a callback to run whenever
75 /// it receives an alias query. Useful for testing that a particular AA result
76 /// is reached.
77 struct TestCustomAAResult : AAResultBase<TestCustomAAResult> {
78 friend AAResultBase<TestCustomAAResult>;
79
80 std::function<void()> CB;
81
TestCustomAAResult__anon7f44cadb0211::TestCustomAAResult82 explicit TestCustomAAResult(std::function<void()> CB)
83 : AAResultBase(), CB(std::move(CB)) {}
TestCustomAAResult__anon7f44cadb0211::TestCustomAAResult84 TestCustomAAResult(TestCustomAAResult &&Arg)
85 : AAResultBase(std::move(Arg)), CB(std::move(Arg.CB)) {}
86
invalidate__anon7f44cadb0211::TestCustomAAResult87 bool invalidate(Function &, const PreservedAnalyses &) { return false; }
88
alias__anon7f44cadb0211::TestCustomAAResult89 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
90 AAQueryInfo &AAQI) {
91 CB();
92 return MayAlias;
93 }
94 };
95 }
96
97 namespace {
98 /// A wrapper pass for the legacy pass manager to use with the above custom AA
99 /// result.
100 class TestCustomAAWrapperPass : public ImmutablePass {
101 std::function<void()> CB;
102 std::unique_ptr<TestCustomAAResult> Result;
103
104 public:
105 static char ID;
106
TestCustomAAWrapperPass(std::function<void ()> CB=std::function<void ()> ())107 explicit TestCustomAAWrapperPass(
108 std::function<void()> CB = std::function<void()>())
109 : ImmutablePass(ID), CB(std::move(CB)) {
110 initializeTestCustomAAWrapperPassPass(*PassRegistry::getPassRegistry());
111 }
112
getAnalysisUsage(AnalysisUsage & AU) const113 void getAnalysisUsage(AnalysisUsage &AU) const override {
114 AU.setPreservesAll();
115 AU.addRequired<TargetLibraryInfoWrapperPass>();
116 }
117
doInitialization(Module & M)118 bool doInitialization(Module &M) override {
119 Result.reset(new TestCustomAAResult(std::move(CB)));
120 return true;
121 }
122
doFinalization(Module & M)123 bool doFinalization(Module &M) override {
124 Result.reset();
125 return true;
126 }
127
getResult()128 TestCustomAAResult &getResult() { return *Result; }
getResult() const129 const TestCustomAAResult &getResult() const { return *Result; }
130 };
131 }
132
133 char TestCustomAAWrapperPass::ID = 0;
134 INITIALIZE_PASS_BEGIN(TestCustomAAWrapperPass, "test-custom-aa",
135 "Test Custom AA Wrapper Pass", false, true)
136 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
137 INITIALIZE_PASS_END(TestCustomAAWrapperPass, "test-custom-aa",
138 "Test Custom AA Wrapper Pass", false, true)
139
140 namespace {
141
142 class AliasAnalysisTest : public testing::Test {
143 protected:
144 LLVMContext C;
145 Module M;
146 TargetLibraryInfoImpl TLII;
147 TargetLibraryInfo TLI;
148 std::unique_ptr<AssumptionCache> AC;
149 std::unique_ptr<BasicAAResult> BAR;
150 std::unique_ptr<AAResults> AAR;
151
AliasAnalysisTest()152 AliasAnalysisTest() : M("AliasAnalysisTest", C), TLI(TLII) {}
153
getAAResults(Function & F)154 AAResults &getAAResults(Function &F) {
155 // Reset the Function AA results first to clear out any references.
156 AAR.reset(new AAResults(TLI));
157
158 // Build the various AA results and register them.
159 AC.reset(new AssumptionCache(F));
160 BAR.reset(new BasicAAResult(M.getDataLayout(), F, TLI, *AC));
161 AAR->addAAResult(*BAR);
162
163 return *AAR;
164 }
165 };
166
TEST_F(AliasAnalysisTest,getModRefInfo)167 TEST_F(AliasAnalysisTest, getModRefInfo) {
168 // Setup function.
169 FunctionType *FTy =
170 FunctionType::get(Type::getVoidTy(C), std::vector<Type *>(), false);
171 auto *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
172 auto *BB = BasicBlock::Create(C, "entry", F);
173 auto IntType = Type::getInt32Ty(C);
174 auto PtrType = Type::getInt32PtrTy(C);
175 auto *Value = ConstantInt::get(IntType, 42);
176 auto *Addr = ConstantPointerNull::get(PtrType);
177 auto Alignment = Align(IntType->getBitWidth() / 8);
178
179 auto *Store1 = new StoreInst(Value, Addr, BB);
180 auto *Load1 = new LoadInst(IntType, Addr, "load", BB);
181 auto *Add1 = BinaryOperator::CreateAdd(Value, Value, "add", BB);
182 auto *VAArg1 = new VAArgInst(Addr, PtrType, "vaarg", BB);
183 auto *CmpXChg1 = new AtomicCmpXchgInst(
184 Addr, ConstantInt::get(IntType, 0), ConstantInt::get(IntType, 1),
185 Alignment, AtomicOrdering::Monotonic, AtomicOrdering::Monotonic,
186 SyncScope::System, BB);
187 auto *AtomicRMW = new AtomicRMWInst(
188 AtomicRMWInst::Xchg, Addr, ConstantInt::get(IntType, 1), Alignment,
189 AtomicOrdering::Monotonic, SyncScope::System, BB);
190
191 ReturnInst::Create(C, nullptr, BB);
192
193 auto &AA = getAAResults(*F);
194
195 // Check basic results
196 EXPECT_EQ(AA.getModRefInfo(Store1, MemoryLocation()), ModRefInfo::Mod);
197 EXPECT_EQ(AA.getModRefInfo(Store1, None), ModRefInfo::Mod);
198 EXPECT_EQ(AA.getModRefInfo(Load1, MemoryLocation()), ModRefInfo::Ref);
199 EXPECT_EQ(AA.getModRefInfo(Load1, None), ModRefInfo::Ref);
200 EXPECT_EQ(AA.getModRefInfo(Add1, MemoryLocation()), ModRefInfo::NoModRef);
201 EXPECT_EQ(AA.getModRefInfo(Add1, None), ModRefInfo::NoModRef);
202 EXPECT_EQ(AA.getModRefInfo(VAArg1, MemoryLocation()), ModRefInfo::ModRef);
203 EXPECT_EQ(AA.getModRefInfo(VAArg1, None), ModRefInfo::ModRef);
204 EXPECT_EQ(AA.getModRefInfo(CmpXChg1, MemoryLocation()), ModRefInfo::ModRef);
205 EXPECT_EQ(AA.getModRefInfo(CmpXChg1, None), ModRefInfo::ModRef);
206 EXPECT_EQ(AA.getModRefInfo(AtomicRMW, MemoryLocation()), ModRefInfo::ModRef);
207 EXPECT_EQ(AA.getModRefInfo(AtomicRMW, None), ModRefInfo::ModRef);
208 }
209
210 class AAPassInfraTest : public testing::Test {
211 protected:
212 LLVMContext C;
213 SMDiagnostic Err;
214 std::unique_ptr<Module> M;
215
216 public:
AAPassInfraTest()217 AAPassInfraTest()
218 : M(parseAssemblyString("define i32 @f(i32* %x, i32* %y) {\n"
219 "entry:\n"
220 " %lx = load i32, i32* %x\n"
221 " %ly = load i32, i32* %y\n"
222 " %sum = add i32 %lx, %ly\n"
223 " ret i32 %sum\n"
224 "}\n",
225 Err, C)) {
226 assert(M && "Failed to build the module!");
227 }
228 };
229
TEST_F(AAPassInfraTest,injectExternalAA)230 TEST_F(AAPassInfraTest, injectExternalAA) {
231 legacy::PassManager PM;
232
233 // Register our custom AA's wrapper pass manually.
234 bool IsCustomAAQueried = false;
235 PM.add(new TestCustomAAWrapperPass([&] { IsCustomAAQueried = true; }));
236
237 // Now add the external AA wrapper with a lambda which queries for the
238 // wrapper around our custom AA and adds it to the results.
239 PM.add(createExternalAAWrapperPass([](Pass &P, Function &, AAResults &AAR) {
240 if (auto *WrapperPass = P.getAnalysisIfAvailable<TestCustomAAWrapperPass>())
241 AAR.addAAResult(WrapperPass->getResult());
242 }));
243
244 // And run a pass that will make some alias queries. This will automatically
245 // trigger the rest of the alias analysis stack to be run. It is analagous to
246 // building a full pass pipeline with any of the existing pass manager
247 // builders.
248 PM.add(new AATestPass());
249 PM.run(*M);
250
251 // Finally, ensure that our custom AA was indeed queried.
252 EXPECT_TRUE(IsCustomAAQueried);
253 }
254
255 } // end anonymous namspace
256