ymandel created this revision.
ymandel added reviewers: xazax.hun, sgatev.
Herald added subscribers: tschuett, steakhal, rnkovacs.
Herald added a project: All.
ymandel requested review of this revision.
Herald added a project: clang.
Google's protobufs are often quite large and their internal state is never worth
modeling in the environment. Exclude them during value construction.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D123032
Files:
clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
clang/unittests/Analysis/FlowSensitive/DataflowEnvironmentTest.cpp
Index: clang/unittests/Analysis/FlowSensitive/DataflowEnvironmentTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/DataflowEnvironmentTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/DataflowEnvironmentTest.cpp
@@ -20,8 +20,8 @@
using namespace clang;
using namespace dataflow;
-using ::testing::ElementsAre;
-using ::testing::Pair;
+using ::testing::IsNull;
+using ::testing::NotNull;
class EnvironmentTest : public ::testing::Test {
DataflowAnalysisContext Context;
@@ -98,4 +98,70 @@
EXPECT_NE(PV, nullptr);
}
+TEST_F(EnvironmentTest, ExcludeProtobufTypes) {
+ using namespace ast_matchers;
+
+ std::string Code = R"cc(
+ namespace proto2 {
+ struct Message {};
+ }
+
+ namespace google {
+ namespace protobuf {
+ struct Message {};
+ }
+ }
+
+ namespace other {
+ namespace google {
+ namespace protobuf {
+ struct Message {};
+ }
+ }
+ }
+
+ struct Foo : public proto2::Message {
+ bool Field;
+ };
+
+ struct Bar : public google::protobuf::Message {
+ bool Field;
+ };
+
+ // Not a protobuf, but looks like it. Verify that it is *not* excluded.
+ struct Zab : public other::google::protobuf::Message {
+ bool Field;
+ };
+
+ void target() {
+ Foo F;
+ Bar B;
+ Zab Z;
+ (void)0;
+ /*[[check]]*/
+ }
+ )cc";
+
+ auto Unit =
+ tooling::buildASTFromCodeWithArgs(Code, {"-fsyntax-only", "-std=c++11"});
+ auto &Context = Unit->getASTContext();
+
+ ASSERT_EQ(Context.getDiagnostics().getClient()->getNumErrors(), 0U);
+
+ auto Results = match(varDecl(eachOf(varDecl(hasName("F")).bind("varF"),
+ varDecl(hasName("B")).bind("varB"),
+ varDecl(hasName("Z")).bind("varZ"))),
+ Context);
+ const auto *F = selectFirst<VarDecl>("varF", Results);
+ ASSERT_TRUE(F != nullptr);
+ const auto *B = selectFirst<VarDecl>("varB", Results);
+ ASSERT_TRUE(B != nullptr);
+ const auto *Z = selectFirst<VarDecl>("varZ", Results);
+ ASSERT_TRUE(Z != nullptr);
+
+ EXPECT_THAT(Env.createValue(F->getType()), IsNull());
+ EXPECT_THAT(Env.createValue(B->getType()), IsNull());
+ EXPECT_THAT(Env.createValue(Z->getType()), NotNull());
+}
+
} // namespace
Index: clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
+++ clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
@@ -493,6 +493,41 @@
return Val;
}
+// Hard code certain types to exclude from modeling. Currently, we limit to
+// Google protobufs, since they can be very large, and have no value in
+// modeling.
+static bool isExcludedRecordType(const RecordType *Ty) {
+ const auto *CD = dyn_cast<CXXRecordDecl>(Ty->getDecl());
+ if (CD == nullptr || !CD->hasDefinition() || CD->getNumBases() != 1)
+ return false;
+
+ QualType BQ = CD->bases_begin()->getType();
+ if (BQ.isNull())
+ return false;
+
+ const RecordType *BaseTy = BQ->getAs<RecordType>();
+ if (BaseTy == nullptr)
+ return false;
+
+ const RecordDecl *RD = BaseTy->getDecl();
+ if (RD->getIdentifier() == nullptr || RD->getName() != "Message")
+ return false;
+
+ const auto *ND = dyn_cast<NamespaceDecl>(RD->getDeclContext());
+ if (ND == nullptr || ND->getIdentifier() == nullptr)
+ return false;
+ if (ND->getName() == "proto2")
+ return true;
+
+ // Check for `::google::protobuf`:
+ if (ND->getName() != "protobuf")
+ return false;
+
+ ND = dyn_cast<NamespaceDecl>(ND->getDeclContext());
+ return ND != nullptr && ND->getParent()->isTranslationUnit() &&
+ ND->getIdentifier() != nullptr && ND->getName() == "google";
+}
+
Value *Environment::createValueUnlessSelfReferential(
QualType Type, llvm::DenseSet<QualType> &Visited, int Depth,
int &CreatedValuesCount) {
@@ -549,7 +584,8 @@
return &takeOwnership(std::make_unique<PointerValue>(PointeeLoc));
}
- if (Type->isStructureOrClassType()) {
+ if (Type->isStructureOrClassType() &&
+ !isExcludedRecordType(Type->getAs<RecordType>())) {
CreatedValuesCount++;
// FIXME: Initialize only fields that are accessed in the context that is
// being analyzed.
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