[PATCH] D102640: [ASTimporter] Remove decl from lookup only if it has decl context

[Balázs Benics via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG88ee91cd8779: [ASTimporter] Remove decl from lookup only if it has decl context (authored by steakhal).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102640/new/

https://reviews.llvm.org/D102640

Files:
  clang/lib/AST/ASTImporter.cpp
  clang/unittests/AST/ASTImporterTest.cpp


Index: clang/unittests/AST/ASTImporterTest.cpp
===================================================================
--- clang/unittests/AST/ASTImporterTest.cpp
+++ clang/unittests/AST/ASTImporterTest.cpp
@@ -5225,6 +5225,40 @@
   EXPECT_TRUE(ImportedOK);
 }
 
+TEST_P(ErrorHandlingTest, ODRViolationWithinTypedefDecls) {
+  // Importing `z` should fail - instead of crashing - due to an ODR violation.
+  // The `bar::e` typedef sets it's DeclContext after the import is done.
+  // However, if the importation fails, it will be left as a nullptr.
+  // During the cleanup of the failed import, we should check whether the
+  // DeclContext is null or not - instead of dereferencing that unconditionally.
+  constexpr auto ToTUCode = R"(
+      namespace X {
+        struct bar {
+          int odr_violation;
+        };
+      })";
+  constexpr auto FromTUCode = R"(
+      namespace X {
+        enum b {};
+        struct bar {
+          typedef b e;
+          static e d;
+        };
+      }
+      int z = X::bar::d;
+      )";
+  Decl *ToTU = getToTuDecl(ToTUCode, Lang_CXX11);
+  static_cast<void>(ToTU);
+  Decl *FromTU = getTuDecl(FromTUCode, Lang_CXX11);
+  auto *FromZ =
+      FirstDeclMatcher<VarDecl>().match(FromTU, varDecl(hasName("z")));
+  ASSERT_TRUE(FromZ);
+  ASSERT_TRUE(FromZ->hasInit());
+
+  auto *ImportedZ = Import(FromZ, Lang_CXX11);
+  EXPECT_FALSE(ImportedZ);
+}
+
 // An error should be set for a class if it had a previous import with an error
 // from another TU.
 TEST_P(ErrorHandlingTest,
Index: clang/lib/AST/ASTImporter.cpp
===================================================================
--- clang/lib/AST/ASTImporter.cpp
+++ clang/lib/AST/ASTImporter.cpp
@@ -8383,7 +8383,11 @@
       // traverse of the 'to' context).
       auto PosF = ImportedFromDecls.find(ToD);
       if (PosF != ImportedFromDecls.end()) {
-        SharedState->removeDeclFromLookup(ToD);
+        // In the case of TypedefNameDecl we create the Decl first and only
+        // then we import and set its DeclContext. So, the DC might not be set
+        // when we reach here.
+        if (ToD->getDeclContext())
+          SharedState->removeDeclFromLookup(ToD);
         ImportedFromDecls.erase(PosF);
       }
 


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