mstorsjo created this revision.
mstorsjo added reviewers: rnk, hans, smeenai.
Herald added a project: clang.
Contrary to MSVC, GCC/MinGW needs to have the dllexport attribute on the
template instantiation declaration, not on the definition.
Previously clang never marked explicit template instantiations as dllexport in
MinGW mode, regardless of where the attribute was placed. This makes Clang
behave like GCC in this regard, and allows using the same attribute form for
both MinGW compilers.
This fixes PR40256.
Repository:
rC Clang
https://reviews.llvm.org/D61118
Files:
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaDeclCXX.cpp
lib/Sema/SemaTemplate.cpp
test/CodeGenCXX/mingw-template-dllexport.cpp
test/SemaCXX/dllexport.cpp
test/SemaCXX/dllimport.cpp
Index: test/SemaCXX/dllimport.cpp
===================================================================
--- test/SemaCXX/dllimport.cpp
+++ test/SemaCXX/dllimport.cpp
@@ -1495,6 +1495,9 @@
#endif
template struct ExplicitlyInstantiatedTemplate<int>;
template <typename T> struct ExplicitlyExportInstantiatedTemplate { void func() {} };
+#ifndef MS
+// expected-warning@+2{{'dllexport' attribute ignored on explicit instantiation definition}}
+#endif
template struct __declspec(dllexport) ExplicitlyExportInstantiatedTemplate<int>;
template <typename T> struct ExplicitlyImportInstantiatedTemplate { void func() {} };
template struct __declspec(dllimport) ExplicitlyImportInstantiatedTemplate<int>;
Index: test/SemaCXX/dllexport.cpp
===================================================================
--- test/SemaCXX/dllexport.cpp
+++ test/SemaCXX/dllexport.cpp
@@ -367,10 +367,16 @@
// Don't instantiate class members of templates with explicit instantiation declarations, even if they are exported.
struct IncompleteType2;
-template <typename T> struct __declspec(dllexport) ExportedTemplateWithExplicitInstantiationDecl { // expected-note{{attribute is here}}
+#ifdef MS
+// expected-note@+2{{attribute is here}}
+#endif
+template <typename T> struct __declspec(dllexport) ExportedTemplateWithExplicitInstantiationDecl {
int f() { return sizeof(T); } // no-error
};
-extern template struct ExportedTemplateWithExplicitInstantiationDecl<IncompleteType2>; // expected-warning{{explicit instantiation declaration should not be 'dllexport'}}
+#ifdef MS
+// expected-warning@+2{{explicit instantiation declaration should not be 'dllexport'}}
+#endif
+extern template struct ExportedTemplateWithExplicitInstantiationDecl<IncompleteType2>;
// Instantiate class members for explicitly instantiated exported templates.
struct IncompleteType3; // expected-note{{forward declaration of 'IncompleteType3'}}
@@ -402,10 +408,17 @@
// Warn about explicit instantiation declarations of dllexport classes.
template <typename T> struct ExplicitInstantiationDeclTemplate {};
-extern template struct __declspec(dllexport) ExplicitInstantiationDeclTemplate<int>; // expected-warning{{explicit instantiation declaration should not be 'dllexport'}} expected-note{{attribute is here}}
+#ifdef MS
+// expected-warning@+2{{explicit instantiation declaration should not be 'dllexport'}} expected-note@+2{{attribute is here}}
+#endif
+extern template struct __declspec(dllexport) ExplicitInstantiationDeclTemplate<int>;
-template <typename T> struct __declspec(dllexport) ExplicitInstantiationDeclExportedTemplate {}; // expected-note{{attribute is here}}
-extern template struct ExplicitInstantiationDeclExportedTemplate<int>; // expected-warning{{explicit instantiation declaration should not be 'dllexport'}}
+template <typename T> struct __declspec(dllexport) ExplicitInstantiationDeclExportedTemplate {};
+#ifdef MS
+// expected-note@-2{{attribute is here}}
+// expected-warning@+2{{explicit instantiation declaration should not be 'dllexport'}}
+#endif
+extern template struct ExplicitInstantiationDeclExportedTemplate<int>;
namespace { struct InternalLinkageType {}; }
struct __declspec(dllexport) PR23308 {
@@ -437,6 +450,9 @@
#endif
template struct ExplicitlyInstantiatedTemplate<int>;
template <typename T> struct ExplicitlyExportInstantiatedTemplate { void func() {} };
+#ifndef MS
+// expected-warning@+2{{'dllexport' attribute ignored on explicit instantiation definition}}
+#endif
template struct __declspec(dllexport) ExplicitlyExportInstantiatedTemplate<int>;
template <typename T> struct ExplicitlyImportInstantiatedTemplate { void func() {} };
template struct __declspec(dllimport) ExplicitlyImportInstantiatedTemplate<int>;
Index: test/CodeGenCXX/mingw-template-dllexport.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/mingw-template-dllexport.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -emit-llvm -triple i686-mingw32 %s -o - | FileCheck %s
+
+template <class T>
+class c {
+ void f();
+};
+
+template <class T> void c<T>::f() {}
+
+template class __declspec(dllexport) c<int>;
+
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN1cIiE1fEv
+
+extern template class __declspec(dllexport) c<char>;
+template class c<char>;
+
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN1cIcE1fEv
+
+extern template class c<double>;
+template class __declspec(dllexport) c<double>;
+
+// CHECK-NOT: define {{.*}} dllexport {{.*}} @_ZN1cIdE1fEv
+
+template <class T>
+struct outer {
+ void f();
+ struct inner {
+ void f();
+ };
+};
+
+template <class T> void outer<T>::f() {}
+template <class T> void outer<T>::inner::f() {}
+
+template class __declspec(dllexport) outer<int>;
+
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN5outerIiE1fEv
+// CHECK-NOT: define {{.*}} dllexport {{.*}} @_ZN5outerIiE5inner1fEv
Index: lib/Sema/SemaTemplate.cpp
===================================================================
--- lib/Sema/SemaTemplate.cpp
+++ lib/Sema/SemaTemplate.cpp
@@ -8709,8 +8709,10 @@
? TSK_ExplicitInstantiationDefinition
: TSK_ExplicitInstantiationDeclaration;
- if (TSK == TSK_ExplicitInstantiationDeclaration) {
- // Check for dllexport class template instantiation declarations.
+ if (TSK == TSK_ExplicitInstantiationDeclaration &&
+ !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+ // Check for dllexport class template instantiation declarations,
+ // except for MinGW mode.
for (const ParsedAttr &AL : Attr) {
if (AL.getKind() == ParsedAttr::AT_DLLExport) {
Diag(ExternLoc,
@@ -8726,6 +8728,18 @@
Diag(A->getLocation(), diag::note_attribute);
}
}
+ if (TSK == TSK_ExplicitInstantiationDefinition &&
+ Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+ // Check for dllexport class template instantiation definitions in MinGW
+ // mode.
+ for (const ParsedAttr &AL : Attr) {
+ if (AL.getKind() == ParsedAttr::AT_DLLExport) {
+ Diag(AL.getLoc(),
+ diag::warn_attribute_dllexport_explicit_instantiation_def);
+ break;
+ }
+ }
+ }
// In MSVC mode, dllimported explicit instantiation definitions are treated as
// instantiation declarations for most purposes.
@@ -8931,6 +8945,14 @@
dllExportImportClassTemplateSpecialization(*this, Def);
}
+ // In MinGW mode, export the template instantiation if the declaration
+ // was marked dllexport.
+ if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
+ Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
+ PrevDecl->hasAttr<DLLExportAttr>()) {
+ dllExportImportClassTemplateSpecialization(*this, Def);
+ }
+
// Set the template specialization kind. Make sure it is set before
// instantiating the members which will trigger ASTConsumer callbacks.
Specialization->setTemplateSpecializationKind(TSK);
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -5697,9 +5697,11 @@
TemplateSpecializationKind TSK = Class->getTemplateSpecializationKind();
- // Ignore explicit dllexport on explicit class template instantiation declarations.
+ // Ignore explicit dllexport on explicit class template instantiation
+ // declarations, except in MinGW mode.
if (ClassExported && !ClassAttr->isInherited() &&
- TSK == TSK_ExplicitInstantiationDeclaration) {
+ TSK == TSK_ExplicitInstantiationDeclaration &&
+ !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
Class->dropAttr<DLLExportAttr>();
return;
}
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -2863,6 +2863,9 @@
def warn_attribute_dllexport_explicit_instantiation_decl : Warning<
"explicit instantiation declaration should not be 'dllexport'">,
InGroup<DiagGroup<"dllexport-explicit-instantiation-decl">>;
+def warn_attribute_dllexport_explicit_instantiation_def : Warning<
+ "'dllexport' attribute ignored on explicit instantiation definition">,
+ InGroup<IgnoredAttributes>;
def warn_invalid_initializer_from_system_header : Warning<
"invalid constructor form class in system header, should not be explicit">,
InGroup<DiagGroup<"invalid-initializer-from-system-header">>;
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