[clang] c9b771b - Keep inherited dllimport/export attrs for explicit specialization of class template member functions
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Fri Oct 7 03:24:40 PDT 2022
Author: Hans Wennborg
Date: 2022-10-07T12:24:19+02:00
New Revision: c9b771b9fc2f17cccd9ccbf8f1d52e2642679b8a
URL: https://github.com/llvm/llvm-project/commit/c9b771b9fc2f17cccd9ccbf8f1d52e2642679b8a
DIFF: https://github.com/llvm/llvm-project/commit/c9b771b9fc2f17cccd9ccbf8f1d52e2642679b8a.diff
LOG: Keep inherited dllimport/export attrs for explicit specialization of class template member functions
Previously we were stripping these normally inherited attributes during
explicit specialization. However for class template member functions
(but not function templates), MSVC keeps the attribute.
This makes Clang match that behavior, and fixes GitHub issue #54717
Differential revision: https://reviews.llvm.org/D135154
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaTemplate.cpp
clang/test/CodeGenCXX/dllexport-members.cpp
clang/test/CodeGenCXX/dllimport-members.cpp
clang/test/SemaCXX/dllexport.cpp
clang/test/SemaCXX/dllimport.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b9a5e0507e35e..7dc779ccc2e24 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -86,6 +86,36 @@ code bases.
typedef char int8_a16 __attribute__((aligned(16)));
int8_a16 array[4]; // Now diagnosed as the element size not being a multiple of the array alignment.
+- When compiling for Windows in MSVC compatibility mode (for example by using
+ clang-cl), the compiler will now propagate dllimport/export declspecs in
+ explicit specializations of class template member functions (`Issue 54717
+ <https://github.com/llvm/llvm-project/issues/54717>`_):
+
+ .. code-block:: c++
+
+ template <typename> struct __declspec(dllexport) S {
+ void f();
+ };
+ template<> void S<int>::f() {} // clang-cl will now dllexport this.
+
+ This matches what MSVC does, so it improves compatibility, but it can also
+ cause errors for code which clang-cl would previously accept, for example:
+
+ .. code-block:: c++
+
+ template <typename> struct __declspec(dllexport) S {
+ void f();
+ };
+ template<> void S<int>::f() = delete; // Error: cannot delete dllexport function.
+
+ .. code-block:: c++
+
+ template <typename> struct __declspec(dllimport) S {
+ void f();
+ };
+ template<> void S<int>::f() {}; // Error: cannot define dllimport function.
+
+ These errors also match MSVC's behavior.
What's New in Clang |release|?
==============================
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 0c7b64c7a94b4..8a721d45e78f0 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3469,6 +3469,8 @@ def warn_attribute_dll_redeclaration : Warning<
InGroup<DiagGroup<"dll-attribute-on-redeclaration">>;
def err_attribute_dllimport_function_definition : Error<
"dllimport cannot be applied to non-inline function definition">;
+def err_attribute_dllimport_function_specialization_definition : Error<
+ "cannot define non-inline dllimport template specialization">;
def err_attribute_dll_deleted : Error<
"attribute %q0 cannot be applied to a deleted function">;
def err_attribute_dllimport_data_definition : Error<
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 60b8d1c3c59c7..760cf7fd805cc 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7041,13 +7041,24 @@ static void checkDLLAttributeRedeclaration(Sema &S, NamedDecl *OldDecl,
(!IsInline || (IsMicrosoftABI && IsTemplate)) && !IsStaticDataMember &&
!NewDecl->isLocalExternDecl() && !IsQualifiedFriend) {
if (IsMicrosoftABI && IsDefinition) {
- S.Diag(NewDecl->getLocation(),
- diag::warn_redeclaration_without_import_attribute)
- << NewDecl;
- S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
- NewDecl->dropAttr<DLLImportAttr>();
- NewDecl->addAttr(
- DLLExportAttr::CreateImplicit(S.Context, NewImportAttr->getRange()));
+ if (IsSpecialization) {
+ S.Diag(
+ NewDecl->getLocation(),
+ diag::err_attribute_dllimport_function_specialization_definition);
+ S.Diag(OldImportAttr->getLocation(), diag::note_attribute);
+ NewDecl->dropAttr<DLLImportAttr>();
+ } else {
+ S.Diag(NewDecl->getLocation(),
+ diag::warn_redeclaration_without_import_attribute)
+ << NewDecl;
+ S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
+ NewDecl->dropAttr<DLLImportAttr>();
+ NewDecl->addAttr(DLLExportAttr::CreateImplicit(
+ S.Context, NewImportAttr->getRange()));
+ }
+ } else if (IsMicrosoftABI && IsSpecialization) {
+ assert(!IsDefinition);
+ // MSVC allows this. Keep the inherited attribute.
} else {
S.Diag(NewDecl->getLocation(),
diag::warn_redeclaration_without_attribute_prev_attribute_ignored)
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index f9f34337384ae..e07ad3a72b4b3 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -8919,9 +8919,12 @@ void Sema::CheckConceptRedefinition(ConceptDecl *NewDecl,
/// \brief Strips various properties off an implicit instantiation
/// that has just been explicitly specialized.
-static void StripImplicitInstantiation(NamedDecl *D) {
- D->dropAttr<DLLImportAttr>();
- D->dropAttr<DLLExportAttr>();
+static void StripImplicitInstantiation(NamedDecl *D, bool MinGW) {
+ if (MinGW || (isa<FunctionDecl>(D) &&
+ cast<FunctionDecl>(D)->isFunctionTemplateSpecialization())) {
+ D->dropAttr<DLLImportAttr>();
+ D->dropAttr<DLLExportAttr>();
+ }
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
FD->setInlineSpecified(false);
@@ -8996,7 +8999,9 @@ Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
if (PrevPointOfInstantiation.isInvalid()) {
// The declaration itself has not actually been instantiated, so it is
// still okay to specialize it.
- StripImplicitInstantiation(PrevDecl);
+ StripImplicitInstantiation(
+ PrevDecl,
+ Context.getTargetInfo().getTriple().isWindowsGNUEnvironment());
return false;
}
// Fall through
diff --git a/clang/test/CodeGenCXX/dllexport-members.cpp b/clang/test/CodeGenCXX/dllexport-members.cpp
index 2ce41d025c3d3..e4effa4c72c72 100644
--- a/clang/test/CodeGenCXX/dllexport-members.cpp
+++ b/clang/test/CodeGenCXX/dllexport-members.cpp
@@ -679,3 +679,21 @@ template __declspec(dllexport) const int MemVarTmpl::StaticVar<ExplicitInst_Expo
// MSC-DAG: @"??$StaticVar at UExplicitSpec_Def_Exported@@@MemVarTmpl@@2HB" = weak_odr dso_local dllexport constant i32 1, comdat, align 4
// GNU-DAG: @_ZN10MemVarTmpl9StaticVarI25ExplicitSpec_Def_ExportedEE = dso_local dllexport constant i32 1, align 4
template<> __declspec(dllexport) const int MemVarTmpl::StaticVar<ExplicitSpec_Def_Exported> = 1;
+
+
+//===----------------------------------------------------------------------===//
+// Class template members
+//===----------------------------------------------------------------------===//
+
+template <typename> struct ClassTmplMem {
+ void __declspec(dllexport) exportedNormal();
+ static void __declspec(dllexport) exportedStatic();
+};
+// MSVC exports explicit specialization of exported class template member function; MinGW does not.
+// M32-DAG: define dso_local dllexport x86_thiscallcc void @"?exportedNormal@?$ClassTmplMem at H@@QAEXXZ"
+// G32-DAG: define dso_local x86_thiscallcc void @_ZN12ClassTmplMemIiE14exportedNormalEv
+template<> void ClassTmplMem<int>::exportedNormal() {}
+
+// M32-DAG: define dso_local dllexport void @"?exportedStatic@?$ClassTmplMem at H@@SAXXZ"
+// G32-DAG: define dso_local void @_ZN12ClassTmplMemIiE14exportedStaticEv
+template<> void ClassTmplMem<int>::exportedStatic() {}
diff --git a/clang/test/CodeGenCXX/dllimport-members.cpp b/clang/test/CodeGenCXX/dllimport-members.cpp
index 3f8a592e24fe0..19bd7fec3f337 100644
--- a/clang/test/CodeGenCXX/dllimport-members.cpp
+++ b/clang/test/CodeGenCXX/dllimport-members.cpp
@@ -875,3 +875,23 @@ USEMV(MemVarTmpl, StaticVar<ExplicitDecl_Imported>)
// GNU-DAG: @_ZN10MemVarTmpl9StaticVarI21ExplicitSpec_ImportedEE = external dllimport constant i32
template<> __declspec(dllimport) const int MemVarTmpl::StaticVar<ExplicitSpec_Imported>;
USEMV(MemVarTmpl, StaticVar<ExplicitSpec_Imported>)
+
+
+//===----------------------------------------------------------------------===//
+// Class template members
+//===----------------------------------------------------------------------===//
+
+template <typename> struct ClassTmplMem {
+ void __declspec(dllimport) importedNormal();
+ static void __declspec(dllimport) importedStatic();
+};
+// MSVC imports explicit specialization of imported class template member function; MinGW does not.
+// M32-DAG: declare dllimport x86_thiscallcc void @"?importedNormal@?$ClassTmplMem at H@@QAEXXZ"
+// G32-DAG: declare dso_local x86_thiscallcc void @_ZN12ClassTmplMemIiE14importedNormalEv
+template<> void ClassTmplMem<int>::importedNormal();
+USEMF(ClassTmplMem<int>, importedNormal);
+
+// M32-DAG: declare dllimport void @"?importedStatic@?$ClassTmplMem at H@@SAXXZ"
+// G32-DAG: declare dso_local void @_ZN12ClassTmplMemIiE14importedStaticEv
+template<> void ClassTmplMem<int>::importedStatic();
+USEMF(ClassTmplMem<int>, importedStatic);
diff --git a/clang/test/SemaCXX/dllexport.cpp b/clang/test/SemaCXX/dllexport.cpp
index 7d8bfdadbb839..bd4b0a7c78df0 100644
--- a/clang/test/SemaCXX/dllexport.cpp
+++ b/clang/test/SemaCXX/dllexport.cpp
@@ -1,11 +1,11 @@
-// RUN: %clang_cc1 -triple i686-win32 -fsyntax-only -fms-extensions -verify -std=c++11 -Wunsupported-dll-base-class-template -DMS %s
-// RUN: %clang_cc1 -triple x86_64-win32 -fsyntax-only -fms-extensions -verify -std=c++1y -Wunsupported-dll-base-class-template -DMS %s
-// RUN: %clang_cc1 -triple i686-mingw32 -fsyntax-only -fms-extensions -verify -std=c++1y -Wunsupported-dll-base-class-template %s
-// RUN: %clang_cc1 -triple x86_64-mingw32 -fsyntax-only -fms-extensions -verify -std=c++11 -Wunsupported-dll-base-class-template %s
-// RUN: %clang_cc1 -triple i686-windows-itanium -fsyntax-only -fms-extensions -verify -std=c++11 -Wunsupported-dll-base-class-template -DWI %s
-// RUN: %clang_cc1 -triple x86_64-windows-itanium -fsyntax-only -fms-extensions -verify -std=c++1y -Wunsupported-dll-base-class-template -DWI %s
-// RUN: %clang_cc1 -triple x86_64-scei-ps4 -fsyntax-only -fdeclspec -verify -std=c++11 -Wunsupported-dll-base-class-template -DWI %s
-// RUN: %clang_cc1 -triple x86_64-sie-ps5 -fsyntax-only -fdeclspec -verify -std=c++1y -Wunsupported-dll-base-class-template -DWI %s
+// RUN: %clang_cc1 -triple i686-win32 -fsyntax-only -fms-extensions -verify -std=c++11 -Wunsupported-dll-base-class-template -DMS %s
+// RUN: %clang_cc1 -triple x86_64-win32 -fsyntax-only -fms-extensions -verify -std=c++1y -Wunsupported-dll-base-class-template -DMS %s
+// RUN: %clang_cc1 -triple i686-mingw32 -fsyntax-only -fms-extensions -verify -std=c++1y -Wunsupported-dll-base-class-template -DGNU %s
+// RUN: %clang_cc1 -triple x86_64-mingw32 -fsyntax-only -fms-extensions -verify -std=c++11 -Wunsupported-dll-base-class-template -DGNU %s
+// RUN: %clang_cc1 -triple i686-windows-itanium -fsyntax-only -fms-extensions -verify -std=c++11 -Wunsupported-dll-base-class-template -DWI %s
+// RUN: %clang_cc1 -triple x86_64-windows-itanium -fsyntax-only -fms-extensions -verify -std=c++1y -Wunsupported-dll-base-class-template -DWI %s
+// RUN: %clang_cc1 -triple x86_64-scei-ps4 -fsyntax-only -fdeclspec -verify -std=c++11 -Wunsupported-dll-base-class-template -DWI %s
+// RUN: %clang_cc1 -triple x86_64-sie-ps5 -fsyntax-only -fdeclspec -verify -std=c++1y -Wunsupported-dll-base-class-template -DWI %s
// Helper structs to make templates more expressive.
struct ImplicitInst_Exported {};
@@ -1087,6 +1087,13 @@ template<typename T> __declspec(dllexport) const int CTMR<T>::StaticConstField
#endif
template<typename T> __declspec(dllexport) constexpr int CTMR<T>::ConstexprField;
+// MSVC exports explicit specialization of exported class template member
+// function, and errors on such definitions. MinGW does not treat them as
+// dllexport.
+#if !defined(GNU)
+// expected-error at +2{{attribute 'dllexport' cannot be applied to a deleted function}}
+#endif
+template <> void ExportClassTmplMembers<int>::normalDecl() = delete;
//===----------------------------------------------------------------------===//
diff --git a/clang/test/SemaCXX/dllimport.cpp b/clang/test/SemaCXX/dllimport.cpp
index c5291d925523d..6ab27433d9e93 100644
--- a/clang/test/SemaCXX/dllimport.cpp
+++ b/clang/test/SemaCXX/dllimport.cpp
@@ -1138,6 +1138,9 @@ template<> __declspec(dllimport) const int MemVarTmpl::StaticVar<ExplicitSpec_De
// Import individual members of a class template.
template<typename T>
struct ImportClassTmplMembers {
+#ifndef GNU
+// expected-note at +2{{attribute is here}}
+#endif
__declspec(dllimport) void normalDecl();
#ifdef GNU
// expected-note at +2{{previous attribute is here}}
@@ -1300,6 +1303,34 @@ template<typename T> __declspec(dllimport) const int CTMR<T>::StaticConstField
template<typename T> __declspec(dllimport) constexpr int CTMR<T>::ConstexprField;
+// MSVC imports explicit specialization of imported class template member
+// function, and errors on such definitions. MinGW does not treat them as
+// dllimport.
+template <typename> struct ClassTmpl {
+#if !defined(GNU)
+// expected-note at +2{{attribute is here}}
+#endif
+ void __declspec(dllimport) importedNormal();
+#if !defined(GNU)
+// expected-note at +2{{attribute is here}}
+#endif
+ static void __declspec(dllimport) importedStatic();
+};
+#if !defined(GNU)
+// expected-error at +2{{cannot define non-inline dllimport template specialization}}
+#endif
+template<> void ClassTmpl<int>::importedNormal() {}
+#if !defined(GNU)
+// expected-error at +2{{cannot define non-inline dllimport template specialization}}
+#endif
+template<> void ClassTmpl<int>::importedStatic() {}
+
+#if !defined(GNU)
+// expected-error at +3{{cannot define non-inline dllimport template specialization}}
+// expected-error at +2{{attribute 'dllimport' cannot be applied to a deleted function}}
+#endif
+template <> void ImportClassTmplMembers<int>::normalDecl() = delete;
+
//===----------------------------------------------------------------------===//
// Class template member templates
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