unittests/Analysis/AliasAnalysisTest.cpp

   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/Support/SourceMgr.h"
  22 #include "gtest/gtest.h"
  23
  24 using namespace llvm;
  25
  26 // Set up some test passes.
  27 namespace llvm {
  28 void initializeAATestPassPass(PassRegistry&);
  29 void initializeTestCustomAAWrapperPassPass(PassRegistry&);
  30 }
  31
  32 namespace {
  33 struct AATestPass : FunctionPass {
  34   static char ID;
  35   AATestPass() : FunctionPass(ID) {
  36     initializeAATestPassPass(*PassRegistry::getPassRegistry());
  37   }
  38
  39   void getAnalysisUsage(AnalysisUsage &AU) const override {
  40     AU.addRequired<AAResultsWrapperPass>();
  41     AU.setPreservesAll();
  42   }
  43
  44   bool runOnFunction(Function &F) override {
  45     AliasAnalysis &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
  46
  47     SetVector<Value *> Pointers;
  48     for (Argument &A : F.args())
  49       if (A.getType()->isPointerTy())
  50         Pointers.insert(&A);
  51     for (Instruction &I : instructions(F))
  52       if (I.getType()->isPointerTy())
  53         Pointers.insert(&I);
  54
  55     for (Value *P1 : Pointers)
  56       for (Value *P2 : Pointers)
  57         (void)AA.alias(P1, LocationSize::unknown(), P2,
  58                        LocationSize::unknown());
  59
  60     return false;
  61   }
  62 };
  63 }
  64
  65 char AATestPass::ID = 0;
  66 INITIALIZE_PASS_BEGIN(AATestPass, "aa-test-pas", "Alias Analysis Test Pass",
  67                       false, true)
  68 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
  69 INITIALIZE_PASS_END(AATestPass, "aa-test-pass", "Alias Analysis Test Pass",
  70                     false, true)
  71
  72 namespace {
  73 /// A test customizable AA result. It merely accepts a callback to run whenever
  74 /// it receives an alias query. Useful for testing that a particular AA result
  75 /// is reached.
  76 struct TestCustomAAResult : AAResultBase<TestCustomAAResult> {
  77   friend AAResultBase<TestCustomAAResult>;
  78
  79   std::function<void()> CB;
  80
  81   explicit TestCustomAAResult(std::function<void()> CB)
  82       : AAResultBase(), CB(std::move(CB)) {}
  83   TestCustomAAResult(TestCustomAAResult &&Arg)
  84       : AAResultBase(std::move(Arg)), CB(std::move(Arg.CB)) {}
  85
  86   bool invalidate(Function &, const PreservedAnalyses &) { return false; }
  87
  88   AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
  89     CB();
  90     return MayAlias;
  91   }
  92 };
  93 }
  94
  95 namespace {
  96 /// A wrapper pass for the legacy pass manager to use with the above custom AA
  97 /// result.
  98 class TestCustomAAWrapperPass : public ImmutablePass {
  99   std::function<void()> CB;
 100   std::unique_ptr<TestCustomAAResult> Result;
 101
 102 public:
 103   static char ID;
 104
 105   explicit TestCustomAAWrapperPass(
 106       std::function<void()> CB = std::function<void()>())
 107       : ImmutablePass(ID), CB(std::move(CB)) {
 108     initializeTestCustomAAWrapperPassPass(*PassRegistry::getPassRegistry());
 109   }
 110
 111   void getAnalysisUsage(AnalysisUsage &AU) const override {
 112     AU.setPreservesAll();
 113     AU.addRequired<TargetLibraryInfoWrapperPass>();
 114   }
 115
 116   bool doInitialization(Module &M) override {
 117     Result.reset(new TestCustomAAResult(std::move(CB)));
 118     return true;
 119   }
 120
 121   bool doFinalization(Module &M) override {
 122     Result.reset();
 123     return true;
 124   }
 125
 126   TestCustomAAResult &getResult() { return *Result; }
 127   const TestCustomAAResult &getResult() const { return *Result; }
 128 };
 129 }
 130
 131 char TestCustomAAWrapperPass::ID = 0;
 132 INITIALIZE_PASS_BEGIN(TestCustomAAWrapperPass, "test-custom-aa",
 133                 "Test Custom AA Wrapper Pass", false, true)
 134 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 135 INITIALIZE_PASS_END(TestCustomAAWrapperPass, "test-custom-aa",
 136                 "Test Custom AA Wrapper Pass", false, true)
 137
 138 namespace {
 139
 140 class AliasAnalysisTest : public testing::Test {
 141 protected:
 142   LLVMContext C;
 143   Module M;
 144   TargetLibraryInfoImpl TLII;
 145   TargetLibraryInfo TLI;
 146   std::unique_ptr<AssumptionCache> AC;
 147   std::unique_ptr<BasicAAResult> BAR;
 148   std::unique_ptr<AAResults> AAR;
 149
 150   AliasAnalysisTest() : M("AliasAnalysisTest", C), TLI(TLII) {}
 151
 152   AAResults &getAAResults(Function &F) {
 153     // Reset the Function AA results first to clear out any references.
 154     AAR.reset(new AAResults(TLI));
 155
 156     // Build the various AA results and register them.
 157     AC.reset(new AssumptionCache(F));
 158     BAR.reset(new BasicAAResult(M.getDataLayout(), F, TLI, *AC));
 159     AAR->addAAResult(*BAR);
 160
 161     return *AAR;
 162   }
 163 };
 164
 165 TEST_F(AliasAnalysisTest, getModRefInfo) {
 166   // Setup function.
 167   FunctionType *FTy =
 168       FunctionType::get(Type::getVoidTy(C), std::vector<Type *>(), false);
 169   auto *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
 170   auto *BB = BasicBlock::Create(C, "entry", F);
 171   auto IntType = Type::getInt32Ty(C);
 172   auto PtrType = Type::getInt32PtrTy(C);
 173   auto *Value = ConstantInt::get(IntType, 42);
 174   auto *Addr = ConstantPointerNull::get(PtrType);
 175
 176   auto *Store1 = new StoreInst(Value, Addr, BB);
 177   auto *Load1 = new LoadInst(IntType, Addr, "load", BB);
 178   auto *Add1 = BinaryOperator::CreateAdd(Value, Value, "add", BB);
 179   auto *VAArg1 = new VAArgInst(Addr, PtrType, "vaarg", BB);
 180   auto *CmpXChg1 = new AtomicCmpXchgInst(
 181       Addr, ConstantInt::get(IntType, 0), ConstantInt::get(IntType, 1),
 182       AtomicOrdering::Monotonic, AtomicOrdering::Monotonic,
 183       SyncScope::System, BB);
 184   auto *AtomicRMW =
 185       new AtomicRMWInst(AtomicRMWInst::Xchg, Addr, ConstantInt::get(IntType, 1),
 186                         AtomicOrdering::Monotonic, SyncScope::System, BB);
 187
 188   ReturnInst::Create(C, nullptr, BB);
 189
 190   auto &AA = getAAResults(*F);
 191
 192   // Check basic results
 193   EXPECT_EQ(AA.getModRefInfo(Store1, MemoryLocation()), ModRefInfo::Mod);
 194   EXPECT_EQ(AA.getModRefInfo(Store1, None), ModRefInfo::Mod);
 195   EXPECT_EQ(AA.getModRefInfo(Load1, MemoryLocation()), ModRefInfo::Ref);
 196   EXPECT_EQ(AA.getModRefInfo(Load1, None), ModRefInfo::Ref);
 197   EXPECT_EQ(AA.getModRefInfo(Add1, MemoryLocation()), ModRefInfo::NoModRef);
 198   EXPECT_EQ(AA.getModRefInfo(Add1, None), ModRefInfo::NoModRef);
 199   EXPECT_EQ(AA.getModRefInfo(VAArg1, MemoryLocation()), ModRefInfo::ModRef);
 200   EXPECT_EQ(AA.getModRefInfo(VAArg1, None), ModRefInfo::ModRef);
 201   EXPECT_EQ(AA.getModRefInfo(CmpXChg1, MemoryLocation()), ModRefInfo::ModRef);
 202   EXPECT_EQ(AA.getModRefInfo(CmpXChg1, None), ModRefInfo::ModRef);
 203   EXPECT_EQ(AA.getModRefInfo(AtomicRMW, MemoryLocation()), ModRefInfo::ModRef);
 204   EXPECT_EQ(AA.getModRefInfo(AtomicRMW, None), ModRefInfo::ModRef);
 205 }
 206
 207 class AAPassInfraTest : public testing::Test {
 208 protected:
 209   LLVMContext C;
 210   SMDiagnostic Err;
 211   std::unique_ptr<Module> M;
 212
 213 public:
 214   AAPassInfraTest()
 215       : M(parseAssemblyString("define i32 @f(i32* %x, i32* %y) {\n"
 216                               "entry:\n"
 217                               "  %lx = load i32, i32* %x\n"
 218                               "  %ly = load i32, i32* %y\n"
 219                               "  %sum = add i32 %lx, %ly\n"
 220                               "  ret i32 %sum\n"
 221                               "}\n",
 222                               Err, C)) {
 223     assert(M && "Failed to build the module!");
 224   }
 225 };
 226
 227 TEST_F(AAPassInfraTest, injectExternalAA) {
 228   legacy::PassManager PM;
 229
 230   // Register our custom AA's wrapper pass manually.
 231   bool IsCustomAAQueried = false;
 232   PM.add(new TestCustomAAWrapperPass([&] { IsCustomAAQueried = true; }));
 233
 234   // Now add the external AA wrapper with a lambda which queries for the
 235   // wrapper around our custom AA and adds it to the results.
 236   PM.add(createExternalAAWrapperPass([](Pass &P, Function &, AAResults &AAR) {
 237     if (auto *WrapperPass = P.getAnalysisIfAvailable<TestCustomAAWrapperPass>())
 238       AAR.addAAResult(WrapperPass->getResult());
 239   }));
 240
 241   // And run a pass that will make some alias queries. This will automatically
 242   // trigger the rest of the alias analysis stack to be run. It is analagous to
 243   // building a full pass pipeline with any of the existing pass manager
 244   // builders.
 245   PM.add(new AATestPass());
 246   PM.run(*M);
 247
 248   // Finally, ensure that our custom AA was indeed queried.
 249   EXPECT_TRUE(IsCustomAAQueried);
 250 }
 251
 252 } // end anonymous namspace