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llvm-mirror/unittests/Analysis/BasicAliasAnalysisTest.cpp
Peter Smith b8d8637f8d [AliasAnalysis] Initialize a member variable that may be used by unit test.
The unit tests in BasicAliasAnalysisTest use the alias analysis API
directly and do not call setAAResults to initalize AAR. This gives a
valgrind error "Conditional Jump depends on unitialized variable".

On most buildbots the variable is nullptr, but in some cases it can be
non nullptr leading to seemingly random failures.

These tests were disabled in r366986. With the initialization they can be
enabled again.

Fixes PR42719

Differential Revision: https://reviews.llvm.org/D65568

llvm-svn: 367662
2019-08-02 08:05:14 +00:00

132 lines
4.5 KiB
C++

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