[PATCH] D126419: [clang][dataflow] Improve handling of constructor initializers.

[Yitzhak Mandelbaum via Phabricator via cfe-commits]

ymandel created this revision.
ymandel added reviewers: sgatev, li.zhe.hua, xazax.hun.
Herald added subscribers: tschuett, steakhal, rnkovacs.
Herald added a project: All.
ymandel requested review of this revision.
Herald added a project: clang.

Currently, we assert that `CXXCtorInitializer`s are field initializers. Replace
the assertion with an early return. Otherwise, we crash every time we process a
constructor with a non-field (e.g. base class) initializer.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126419

Files:
  clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
  clang/unittests/Analysis/FlowSensitive/TransferTest.cpp


Index: clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
===================================================================
--- clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
+++ clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
@@ -1274,6 +1274,49 @@
       });
 }
 
+TEST_F(TransferTest, BaseClassInitializer) {
+  using ast_matchers::cxxConstructorDecl;
+  using ast_matchers::hasName;
+  using ast_matchers::ofClass;
+
+  std::string Code = R"(
+    class A {
+    public:
+      A(int I) : Bar(I) {}
+      int Bar;
+    };
+
+    class B : public A {
+    public:
+      B(int I) : A(I) {
+        (void)0;
+        // [[p]]
+      }
+    };
+  )";
+  ASSERT_THAT_ERROR(
+      test::checkDataflow<NoopAnalysis>(
+          Code, cxxConstructorDecl(ofClass(hasName("B"))),
+          [](ASTContext &C, Environment &) {
+            return NoopAnalysis(C, /*ApplyBuiltinTransfer=*/true);
+          },
+          [](llvm::ArrayRef<
+                 std::pair<std::string, DataflowAnalysisState<NoopLattice>>>
+                 Results,
+             ASTContext &ASTCtx) {
+            // Regression test to verify that base-class initializers do not
+            // trigger an assertion. If we add support for such initializers in
+            // the future, we can expand this test to check more specific
+            // properties.
+            EXPECT_THAT(Results, ElementsAre(Pair("p", _)));
+          },
+          {"-fsyntax-only", "-fno-delayed-template-parsing",
+           "-std=" + std::string(LangStandard::getLangStandardForKind(
+                                     LangStandard::lang_cxx17)
+                                     .getName())}),
+      llvm::Succeeded());
+}
+
 TEST_F(TransferTest, ReferenceMember) {
   std::string Code = R"(
     struct A {
Index: clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
+++ clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
@@ -257,6 +257,11 @@
   const CXXCtorInitializer *Initializer = CfgInit.getInitializer();
   assert(Initializer != nullptr);
 
+  const FieldDecl *Member = Initializer->getMember();
+  if (Member == nullptr)
+    // Not a field initializer.
+    return;
+
   auto *InitStmt = Initializer->getInit();
   assert(InitStmt != nullptr);
 
@@ -269,9 +274,6 @@
   if (InitStmtVal == nullptr)
     return;
 
-  const FieldDecl *Member = Initializer->getMember();
-  assert(Member != nullptr);
-
   if (Member->getType()->isReferenceType()) {
     auto &MemberLoc = ThisLoc.getChild(*Member);
     State.Env.setValue(MemberLoc,


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D126419.432113.patch
Type: text/x-patch
Size: 2698 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20220525/a9be5b23/attachment.bin>