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[clang][dataflow] Fix incorrect CXXThisExpr pointee for lambdas 

When constructing the `Environment`, the `this` pointee is established
for a `CXXMethodDecl` by looking at its parent. However, inside of
lambdas, a `CXXThisExpr` refers to the captured `this` coming from the
enclosing member function.

When establishing the `this` pointee for a function, we check whether
the function is a lambda, and check for an enclosing member function
to establish the `this` pointee storage location.

Differential Revision: https://reviews.llvm.org/D126413
This commit is contained in:
Eric Li 2022-05-25 20:15:46 +00:00
parent 33b598a808
commit 5520c58390
2 changed files with 112 additions and 1 deletions
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7
clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
View File

@ -216,7 +216,12 @@ Environment::Environment(DataflowAnalysisContext &DACtx,
}
if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(&DeclCtx)) {
if (!MethodDecl->isStatic()) {
auto *Parent = MethodDecl->getParent();
assert(Parent != nullptr);
if (Parent->isLambda())
MethodDecl = dyn_cast<CXXMethodDecl>(Parent->getDeclContext());
if (MethodDecl && !MethodDecl->isStatic()) {
QualType ThisPointeeType = MethodDecl->getThisObjectType();
// FIXME: Add support for union types.
if (!ThisPointeeType->isUnionType()) {

106
clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
View File

@ -1476,6 +1476,112 @@ TEST_F(TransferTest, ClassThisMember) {
});
}
TEST_F(TransferTest, StructThisInLambda) {
std::string ThisCaptureCode = R"(
struct A {
void frob() {
[this]() {
int Foo = Bar;
// [[p1]]
}();
}
int Bar;
};
)";
runDataflow(
ThisCaptureCode,
[](llvm::ArrayRef<
std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
Results,
ASTContext &ASTCtx) {
ASSERT_THAT(Results, ElementsAre(Pair("p1", _)));
const Environment &Env = Results[0].second.Env;
const auto *ThisLoc = dyn_cast<AggregateStorageLocation>(
Env.getThisPointeeStorageLocation());
ASSERT_THAT(ThisLoc, NotNull());
const ValueDecl *BarDecl = findValueDecl(ASTCtx, "Bar");
ASSERT_THAT(BarDecl, NotNull());
const auto *BarLoc =
cast<ScalarStorageLocation>(&ThisLoc->getChild(*BarDecl));
ASSERT_TRUE(isa_and_nonnull<ScalarStorageLocation>(BarLoc));
const Value *BarVal = Env.getValue(*BarLoc);
ASSERT_TRUE(isa_and_nonnull<IntegerValue>(BarVal));
const ValueDecl *FooDecl = findValueDecl(ASTCtx, "Foo");
ASSERT_THAT(FooDecl, NotNull());
EXPECT_EQ(Env.getValue(*FooDecl, SkipPast::None), BarVal);
},
LangStandard::lang_cxx17, /*ApplyBuiltinTransfer=*/true, "operator()");
std::string RefCaptureDefaultCode = R"(
struct A {
void frob() {
[&]() {
int Foo = Bar;
// [[p2]]
}();
}
int Bar;
};
)";
runDataflow(
RefCaptureDefaultCode,
[](llvm::ArrayRef<
std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
Results,
ASTContext &ASTCtx) {
ASSERT_THAT(Results, ElementsAre(Pair("p2", _)));
const Environment &Env = Results[0].second.Env;
const auto *ThisLoc = dyn_cast<AggregateStorageLocation>(
Env.getThisPointeeStorageLocation());
ASSERT_THAT(ThisLoc, NotNull());
const ValueDecl *BarDecl = findValueDecl(ASTCtx, "Bar");
ASSERT_THAT(BarDecl, NotNull());
const auto *BarLoc =
cast<ScalarStorageLocation>(&ThisLoc->getChild(*BarDecl));
ASSERT_TRUE(isa_and_nonnull<ScalarStorageLocation>(BarLoc));
const Value *BarVal = Env.getValue(*BarLoc);
ASSERT_TRUE(isa_and_nonnull<IntegerValue>(BarVal));
const ValueDecl *FooDecl = findValueDecl(ASTCtx, "Foo");
ASSERT_THAT(FooDecl, NotNull());
EXPECT_EQ(Env.getValue(*FooDecl, SkipPast::None), BarVal);
},
LangStandard::lang_cxx17, /*ApplyBuiltinTransfer=*/true, "operator()");
std::string FreeFunctionLambdaCode = R"(
void foo() {
int Bar;
[&]() {
int Foo = Bar;
// [[p3]]
}();
}
)";
runDataflow(
FreeFunctionLambdaCode,
[](llvm::ArrayRef<
std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
Results,
ASTContext &ASTCtx) {
ASSERT_THAT(Results, ElementsAre(Pair("p3", _)));
const Environment &Env = Results[0].second.Env;
EXPECT_THAT(Env.getThisPointeeStorageLocation(), IsNull());
},
LangStandard::lang_cxx17, /*ApplyBuiltinTransfer=*/true, "operator()");
}
TEST_F(TransferTest, ConstructorInitializer) {
std::string Code = R"(
struct target {