[PATCH] D53697: [ASTImporter][Structural Eq] Check for isBeingDefined

[Gabor Marton via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rC345760: [ASTImporter][Structural Eq] Check for isBeingDefined (authored by martong, committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D53697?vs=171723&id=171984#toc

Repository:
  rC Clang

https://reviews.llvm.org/D53697

Files:
  lib/AST/ASTStructuralEquivalence.cpp
  unittests/AST/ASTImporterTest.cpp


Index: lib/AST/ASTStructuralEquivalence.cpp
===================================================================
--- lib/AST/ASTStructuralEquivalence.cpp
+++ lib/AST/ASTStructuralEquivalence.cpp
@@ -1016,7 +1016,8 @@
     return false;
 
   // Compare the definitions of these two records. If either or both are
-  // incomplete, we assume that they are equivalent.
+  // incomplete (i.e. it is a forward decl), we assume that they are
+  // equivalent.
   D1 = D1->getDefinition();
   D2 = D2->getDefinition();
   if (!D1 || !D2)
@@ -1031,6 +1032,11 @@
     if (D1->hasExternalLexicalStorage() || D2->hasExternalLexicalStorage())
       return true;
 
+  // If one definition is currently being defined, we do not compare for
+  // equality and we assume that the decls are equal.
+  if (D1->isBeingDefined() || D2->isBeingDefined())
+    return true;
+
   if (auto *D1CXX = dyn_cast<CXXRecordDecl>(D1)) {
     if (auto *D2CXX = dyn_cast<CXXRecordDecl>(D2)) {
       if (D1CXX->hasExternalLexicalStorage() &&
Index: unittests/AST/ASTImporterTest.cpp
===================================================================
--- unittests/AST/ASTImporterTest.cpp
+++ unittests/AST/ASTImporterTest.cpp
@@ -3726,6 +3726,45 @@
   EXPECT_EQ(To1->getPreviousDecl(), To0);
 }
 
+TEST_P(ASTImporterTestBase,
+    ImportShouldNotReportFalseODRErrorWhenRecordIsBeingDefined) {
+  {
+    Decl *FromTU = getTuDecl(
+        R"(
+            template <typename T>
+            struct B;
+            )",
+        Lang_CXX, "input0.cc");
+    auto *FromD = FirstDeclMatcher<ClassTemplateDecl>().match(
+        FromTU, classTemplateDecl(hasName("B")));
+
+    Import(FromD, Lang_CXX);
+  }
+
+  {
+    Decl *FromTU = getTuDecl(
+        R"(
+            template <typename T>
+            struct B {
+              void f();
+              B* b;
+            };
+            )",
+        Lang_CXX, "input1.cc");
+    FunctionDecl *FromD = FirstDeclMatcher<FunctionDecl>().match(
+        FromTU, functionDecl(hasName("f")));
+    Import(FromD, Lang_CXX);
+    auto *FromCTD = FirstDeclMatcher<ClassTemplateDecl>().match(
+        FromTU, classTemplateDecl(hasName("B")));
+    auto *ToCTD = cast<ClassTemplateDecl>(Import(FromCTD, Lang_CXX));
+    EXPECT_TRUE(ToCTD->isThisDeclarationADefinition());
+
+    // We expect no (ODR) warning during the import.
+    auto *ToTU = ToAST->getASTContext().getTranslationUnitDecl();
+    EXPECT_EQ(0u, ToTU->getASTContext().getDiagnostics().getNumWarnings());
+  }
+}
+
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, DeclContextTest,
                         ::testing::Values(ArgVector()), );
 


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