martong created this revision.
martong added reviewers: a.sidorin, xazax.hun, szepet.
Herald added subscribers: cfe-commits, dkrupp, rnkovacs.
During import of a class template, lookup may find a forward declaration and
structural match falsely reports equivalency in between a fwd decl and a
definition. This results that some definitions are not imported if we had
imported a fwd decl previously. This patch gives a fix.
Repository:
rC Clang
https://reviews.llvm.org/D46353
Files:
lib/AST/ASTImporter.cpp
unittests/AST/ASTImporterTest.cpp
Index: unittests/AST/ASTImporterTest.cpp
===================================================================
--- unittests/AST/ASTImporterTest.cpp
+++ unittests/AST/ASTImporterTest.cpp
@@ -1431,6 +1431,39 @@
MatchVerifier<Decl>{}.match(To->getTranslationUnitDecl(), Pattern));
}
+TEST_P(ASTImporterTestBase, ImportDefinitionOfClassTemplateAfterFwdDecl) {
+ {
+ 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();
+ };
+ )",
+ 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());
+ }
+}
+
INSTANTIATE_TEST_CASE_P(
ParameterizedTests, ASTImporterTestBase,
::testing::Values(ArgVector(), ArgVector{"-fdelayed-template-parsing"}),);
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -4077,8 +4077,13 @@
if (auto *FoundTemplate = dyn_cast<ClassTemplateDecl>(Found)) {
if (IsStructuralMatch(D, FoundTemplate)) {
// The class templates structurally match; call it the same template.
- // FIXME: We may be filling in a forward declaration here. Handle
- // this case!
+
+ // We found a forward declaration but the class to be imported has a
+ // definition.
+ if (D->isThisDeclarationADefinition() &&
+ !FoundTemplate->isThisDeclarationADefinition())
+ continue;
+
Importer.Imported(D->getTemplatedDecl(),
FoundTemplate->getTemplatedDecl());
return Importer.Imported(D, FoundTemplate);
Index: unittests/AST/ASTImporterTest.cpp
===================================================================
--- unittests/AST/ASTImporterTest.cpp
+++ unittests/AST/ASTImporterTest.cpp
@@ -1431,6 +1431,39 @@
MatchVerifier<Decl>{}.match(To->getTranslationUnitDecl(), Pattern));
}
+TEST_P(ASTImporterTestBase, ImportDefinitionOfClassTemplateAfterFwdDecl) {
+ {
+ 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();
+ };
+ )",
+ 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());
+ }
+}
+
INSTANTIATE_TEST_CASE_P(
ParameterizedTests, ASTImporterTestBase,
::testing::Values(ArgVector(), ArgVector{"-fdelayed-template-parsing"}),);
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -4077,8 +4077,13 @@
if (auto *FoundTemplate = dyn_cast<ClassTemplateDecl>(Found)) {
if (IsStructuralMatch(D, FoundTemplate)) {
// The class templates structurally match; call it the same template.
- // FIXME: We may be filling in a forward declaration here. Handle
- // this case!
+
+ // We found a forward declaration but the class to be imported has a
+ // definition.
+ if (D->isThisDeclarationADefinition() &&
+ !FoundTemplate->isThisDeclarationADefinition())
+ continue;
+
Importer.Imported(D->getTemplatedDecl(),
FoundTemplate->getTemplatedDecl());
return Importer.Imported(D, FoundTemplate);
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