132 lines
4.5 KiB
C++
132 lines
4.5 KiB
C++
//===- BasicAliasAnalysisTest.cpp - Unit tests for BasicAA ----------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Targeted tests that are hard/convoluted to make happen with just `opt`.
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//
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#include "llvm/Analysis/BasicAliasAnalysis.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/AsmParser/Parser.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Support/SourceMgr.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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// FIXME: This is duplicated between this file and MemorySSATest. Refactor.
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const static char DLString[] = "e-i64:64-f80:128-n8:16:32:64-S128";
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/// There's a lot of common setup between these tests. This fixture helps reduce
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/// that. Tests should mock up a function, store it in F, and then call
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/// setupAnalyses().
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class BasicAATest : public testing::Test {
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protected:
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// N.B. Many of these members depend on each other (e.g. the Module depends on
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// the Context, etc.). So, order matters here (and in TestAnalyses).
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LLVMContext C;
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Module M;
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IRBuilder<> B;
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DataLayout DL;
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TargetLibraryInfoImpl TLII;
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TargetLibraryInfo TLI;
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Function *F;
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// Things that we need to build after the function is created.
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struct TestAnalyses {
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DominatorTree DT;
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AssumptionCache AC;
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BasicAAResult BAA;
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AAQueryInfo AAQI;
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TestAnalyses(BasicAATest &Test)
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: DT(*Test.F), AC(*Test.F), BAA(Test.DL, *Test.F, Test.TLI, AC, &DT),
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AAQI() {}
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};
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llvm::Optional<TestAnalyses> Analyses;
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TestAnalyses &setupAnalyses() {
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assert(F);
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Analyses.emplace(*this);
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return Analyses.getValue();
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}
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public:
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BasicAATest()
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: M("BasicAATest", C), B(C), DL(DLString), TLI(TLII), F(nullptr) {}
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};
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// Check that a function arg can't trivially alias a global when we're accessing
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// >sizeof(global) bytes through that arg, unless the access size is just an
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// upper-bound.
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TEST_F(BasicAATest, AliasInstWithObjectOfImpreciseSize) {
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F = Function::Create(
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FunctionType::get(B.getVoidTy(), {B.getInt32Ty()->getPointerTo()}, false),
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GlobalValue::ExternalLinkage, "F", &M);
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BasicBlock *Entry(BasicBlock::Create(C, "", F));
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B.SetInsertPoint(Entry);
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Value *IncomingI32Ptr = F->arg_begin();
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auto *GlobalPtr =
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cast<GlobalVariable>(M.getOrInsertGlobal("some_global", B.getInt8Ty()));
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// Without sufficiently restricted linkage/an init, some of the object size
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// checking bits get more conservative.
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GlobalPtr->setLinkage(GlobalValue::LinkageTypes::InternalLinkage);
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GlobalPtr->setInitializer(B.getInt8(0));
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auto &AllAnalyses = setupAnalyses();
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BasicAAResult &BasicAA = AllAnalyses.BAA;
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AAQueryInfo &AAQI = AllAnalyses.AAQI;
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ASSERT_EQ(
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BasicAA.alias(MemoryLocation(IncomingI32Ptr, LocationSize::precise(4)),
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MemoryLocation(GlobalPtr, LocationSize::precise(1)), AAQI),
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AliasResult::NoAlias);
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ASSERT_EQ(
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BasicAA.alias(MemoryLocation(IncomingI32Ptr, LocationSize::upperBound(4)),
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MemoryLocation(GlobalPtr, LocationSize::precise(1)), AAQI),
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AliasResult::MayAlias);
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}
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// Check that we fall back to MayAlias if we see an access of an entire object
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// that's just an upper-bound.
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TEST_F(BasicAATest, AliasInstWithFullObjectOfImpreciseSize) {
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F = Function::Create(
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FunctionType::get(B.getVoidTy(), {B.getInt64Ty()}, false),
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GlobalValue::ExternalLinkage, "F", &M);
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BasicBlock *Entry(BasicBlock::Create(C, "", F));
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B.SetInsertPoint(Entry);
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Value *ArbitraryI32 = F->arg_begin();
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AllocaInst *I8 = B.CreateAlloca(B.getInt8Ty(), B.getInt32(2));
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auto *I8AtUncertainOffset =
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cast<GetElementPtrInst>(B.CreateGEP(B.getInt8Ty(), I8, ArbitraryI32));
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auto &AllAnalyses = setupAnalyses();
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BasicAAResult &BasicAA = AllAnalyses.BAA;
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AAQueryInfo &AAQI = AllAnalyses.AAQI;
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ASSERT_EQ(BasicAA.alias(
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MemoryLocation(I8, LocationSize::precise(2)),
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MemoryLocation(I8AtUncertainOffset, LocationSize::precise(1)),
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AAQI),
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AliasResult::PartialAlias);
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ASSERT_EQ(BasicAA.alias(
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MemoryLocation(I8, LocationSize::upperBound(2)),
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MemoryLocation(I8AtUncertainOffset, LocationSize::precise(1)),
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AAQI),
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AliasResult::MayAlias);
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}
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