Hi rnk, nrieck,
This implements what I believe is the final piece of PR11170.
Consider the following code:
template <typename T> class Base {};
class __declspec(dllexport) class Derived : public Base<int> {}
When the base of an exported or imported class is a class template
specialization, MSVC will propagate the dll attribute to the base. In the
example code, Base<int> becomes a dllexported class.
My patch does this when the base hasn't been instantiated yet (unless that
instantiation already has the attribute), and warns otherwise. This is
different from MSVC, which allows changing a specialization back and forth
between dllimport and dllexport and seems to let the last one win. Changing the
dll attribute after instantiation would be hard for us, and doesn't seem to
come up in practice, so I think this is a reasonable limitation to have.
MinGW doesn't do this propagation thing.
http://reviews.llvm.org/D4264
Files:
include/clang/Basic/DiagnosticGroups.td
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaDeclCXX.cpp
test/CodeGenCXX/dllexport.cpp
test/CodeGenCXX/dllimport.cpp
test/SemaCXX/dllexport.cpp
test/SemaCXX/dllimport.cpp
Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td
+++ include/clang/Basic/DiagnosticGroups.td
@@ -34,6 +34,7 @@
def BitFieldConstantConversion : DiagGroup<"bitfield-constant-conversion">;
def ConstantConversion :
DiagGroup<"constant-conversion", [ BitFieldConstantConversion ] >;
+def DLLBaseClassTemplate : DiagGroup<"unsupported-dll-base-class-template">;
def LiteralConversion : DiagGroup<"literal-conversion">;
def StringConversion : DiagGroup<"string-conversion">;
def SignConversion : DiagGroup<"sign-conversion">;
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -2130,6 +2130,13 @@
InGroup<DiagGroup<"dllimport-static-field-def">>;
def err_attribute_dll_member_of_dll_class : Error<
"attribute %q0 cannot be applied to member of %q1 class">;
+def warn_attribute_dll_instantiated_base_class : Warning<
+ "propagating dll attribute to already instantiated base class template "
+ "%select{without dll attribute|with different dll attribute}0 is unsupported">,
+ InGroup<DLLBaseClassTemplate>;
+def warn_attribute_dll_templated_base_class_mismatch : Warning<
+ "propagating dll attribute to templated base class with different dll attribute is unsupported">,
+ InGroup<DLLBaseClassTemplate>;
def err_attribute_weakref_not_static : Error<
"weakref declaration must have internal linkage">;
def err_attribute_weakref_not_global_context : Error<
@@ -3405,8 +3412,12 @@
"%select{implicit|explicit}0 instantiation of undefined template %1">;
def err_implicit_instantiate_member_undefined : Error<
"implicit instantiation of undefined member %0">;
+def note_template_class_instantiation_was_here : Note<
+ "class template %0 was instantiated here">;
def note_template_class_instantiation_here : Note<
"in instantiation of template class %0 requested here">;
+def note_template_class_declaration_attr_here : Note<
+ "class template %0 was declared '%1' here">;
def note_template_member_class_here : Note<
"in instantiation of member class %0 requested here">;
def note_template_member_function_here : Note<
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -1296,6 +1296,46 @@
return false;
}
+static void propagateDLLAttrToBaseClassTemplate(
+ Sema &S, CXXRecordDecl *Class, Attr *ClassAttr,
+ ClassTemplateSpecializationDecl *BaseTemplateSpec, SourceLocation BaseLoc) {
+ if (Attr *BaseTemplateAttr = getDLLAttr(
+ BaseTemplateSpec->getSpecializedTemplate()->getTemplatedDecl())) {
+ if (BaseTemplateAttr->getKind() == ClassAttr->getKind())
+ return;
+
+ S.Diag(BaseLoc, diag::warn_attribute_dll_templated_base_class_mismatch);
+ S.Diag(ClassAttr->getLocation(), diag::note_attribute);
+ S.Diag(BaseTemplateAttr->getLocation(),
+ diag::note_template_class_declaration_attr_here)
+ << BaseTemplateSpec->getSpecializedTemplate()->getTemplatedDecl()
+ << BaseTemplateAttr->getSpelling();
+ return;
+ }
+
+ if (BaseTemplateSpec->getSpecializationKind() != TSK_Undeclared) {
+ bool DifferentAttribute = false;
+ if (Attr *SpecializationAttr = getDLLAttr(BaseTemplateSpec)) {
+ if (SpecializationAttr->getKind() == ClassAttr->getKind()) {
+ return;
+ }
+ DifferentAttribute = true;
+ }
+
+ S.Diag(BaseLoc, diag::warn_attribute_dll_instantiated_base_class)
+ << DifferentAttribute;
+ S.Diag(ClassAttr->getLocation(), diag::note_attribute);
+ S.Diag(BaseTemplateSpec->getPointOfInstantiation(),
+ diag::note_template_class_instantiation_was_here)
+ << BaseTemplateSpec;
+
+ return;
+ }
+ auto *NewAttr = cast<InheritableAttr>(ClassAttr->clone(S.getASTContext()));
+ NewAttr->setInherited(true);
+ BaseTemplateSpec->addAttr(NewAttr);
+}
+
/// \brief Check the validity of a C++ base class specifier.
///
/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
@@ -1362,6 +1402,17 @@
return nullptr;
}
+ // For the MS ABI, propagate DLL attributes to base class templates.
+ if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
+ if (Attr *ClassAttr = getDLLAttr(Class)) {
+ if (auto *BaseTemplate = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
+ BaseType->getAsCXXRecordDecl())) {
+ propagateDLLAttrToBaseClassTemplate(*this, Class, ClassAttr,
+ BaseTemplate, BaseLoc);
+ }
+ }
+ }
+
// C++ [class.derived]p2:
// The class-name in a base-specifier shall not be an incompletely
// defined class.
@@ -4361,9 +4412,6 @@
// FIXME: MSVC's docs say all bases must be exportable, but this doesn't
// seem to be true in practice?
- // FIXME: We also need to propagate the attribute upwards to class template
- // specialization bases.
-
for (Decl *Member : Class->decls()) {
VarDecl *VD = dyn_cast<VarDecl>(Member);
CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Member);
@@ -4385,7 +4433,7 @@
if (InheritableAttr *MemberAttr = getDLLAttr(Member)) {
if (S.Context.getTargetInfo().getCXXABI().isMicrosoft() &&
- !MemberAttr->isInherited()) {
+ !MemberAttr->isInherited() && !ClassAttr->isInherited()) {
S.Diag(MemberAttr->getLocation(),
diag::err_attribute_dll_member_of_dll_class)
<< MemberAttr << ClassAttr;
Index: test/CodeGenCXX/dllexport.cpp
===================================================================
--- test/CodeGenCXX/dllexport.cpp
+++ test/CodeGenCXX/dllexport.cpp
@@ -20,6 +20,7 @@
#define UNIQ(name) JOIN(name, __LINE__)
#define USEVAR(var) int UNIQ(use)() { return var; }
#define USE(func) void UNIQ(use)() { func(); }
+#define USEMEMFUNC(class, func) void (class::*UNIQ(use)())() { return &class::func; }
#define INSTVAR(var) template int var;
#define INST(func) template void func();
@@ -568,3 +569,46 @@
// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?foo@S@ReferencedInlineMethodInNestedClass@@QAEXXZ"
// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?bar@T@S@ReferencedInlineMethodInNestedClass@@QAEXXZ"
}
+
+template <typename T> struct ClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllexport) ExportedClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllimport) ImportedClassTemplate { void func() {} };
+
+// MS: ClassTemplate<int> gets exported.
+struct __declspec(dllexport) DerivedFromTemplate : public ClassTemplate<int> {};
+USEMEMFUNC(ClassTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ClassTemplate@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIiE4funcEv
+
+// ExportedTemplate is already exported.
+struct __declspec(dllexport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN21ExportedClassTemplateIiE4funcEv
+
+// Base class template has different attribute.
+struct __declspec(dllexport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+USEMEMFUNC(ImportedClassTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ImportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: declare dllimport x86_thiscallcc void @_ZN21ImportedClassTemplateIiE4funcEv
+
+// Base class already instantiated without dll attribute.
+struct DerivedFromTemplateD : public ClassTemplate<double> {};
+struct __declspec(dllexport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+USEMEMFUNC(ClassTemplate<double>, func)
+// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?func@?$ClassTemplate@N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIdE4funcEv
+
+// MS: Base class already instantiated with different dll attribute.
+struct __declspec(dllimport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+struct __declspec(dllexport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+USEMEMFUNC(ClassTemplate<bool>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ClassTemplate@_N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIbE4funcEv
+
+// MS: A dll attribute propagates through multiple levels of instantiation.
+template <typename T> struct TopClass { void func() {} };
+template <typename T> struct MiddleClass : public TopClass<T> { };
+struct __declspec(dllexport) BottomClas : public MiddleClass<int> { };
+USEMEMFUNC(TopClass<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$TopClass@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN8TopClassIiE4funcEv
Index: test/CodeGenCXX/dllimport.cpp
===================================================================
--- test/CodeGenCXX/dllimport.cpp
+++ test/CodeGenCXX/dllimport.cpp
@@ -649,3 +649,47 @@
// MSC-DAG: @"\01?x@?$D@$0CK@@PR19933@@2HA" = available_externally dllimport global i32 43
// MSC-DAG: @"\01?y@?$D@$0CK@@PR19933@@2HA" = available_externally dllimport global i32 0
}
+
+template <typename T> struct ClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllexport) ExportedClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllimport) ImportedClassTemplate { void func() {} };
+
+// MS: ClassTemplate<int> gets imported.
+struct __declspec(dllimport) DerivedFromTemplate : public ClassTemplate<int> {};
+USEMEMFUNC(ClassTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ClassTemplate@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIiE4funcEv
+
+// ImportedTemplate is already imported.
+struct __declspec(dllimport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+USEMEMFUNC(ImportedClassTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ImportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: declare dllimport x86_thiscallcc void @_ZN21ImportedClassTemplateIiE4funcEv
+
+// Base class template has different attribute.
+struct __declspec(dllimport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+USEMEMFUNC(ExportedClassTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN21ExportedClassTemplateIiE4funcEv
+
+// Base class already instantiated without attribute.
+struct DerivedFromTemplateD : public ClassTemplate<double> {};
+struct __declspec(dllimport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+USEMEMFUNC(ClassTemplate<double>, func)
+// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?func@?$ClassTemplate@N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIdE4funcEv
+
+// MS: Base class already instantiated with dfferent attribute.
+struct __declspec(dllexport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+struct __declspec(dllimport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+USEMEMFUNC(ClassTemplate<bool>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ClassTemplate@_N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIbE4funcEv
+
+// MS: A dll attribute propagates through multiple levels of instantiation.
+template <typename T> struct TopClass { void func() {} };
+template <typename T> struct MiddleClass : public TopClass<T> { };
+struct __declspec(dllimport) BottomClas : public MiddleClass<int> { };
+USEMEMFUNC(TopClass<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$TopClass@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN8TopClassIiE4funcEv
Index: test/SemaCXX/dllexport.cpp
===================================================================
--- test/SemaCXX/dllexport.cpp
+++ test/SemaCXX/dllexport.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple i686-win32 -fsyntax-only -verify -std=c++11 %s
-// RUN: %clang_cc1 -triple x86_64-win32 -fsyntax-only -verify -std=c++1y %s
+// RUN: %clang_cc1 -triple i686-win32 -fsyntax-only -verify -std=c++11 -DMS %s
+// RUN: %clang_cc1 -triple x86_64-win32 -fsyntax-only -verify -std=c++1y -DMS %s
// RUN: %clang_cc1 -triple i686-mingw32 -fsyntax-only -verify -std=c++1y %s
// RUN: %clang_cc1 -triple x86_64-mingw32 -fsyntax-only -verify -std=c++11 %s
@@ -316,7 +316,48 @@
class __declspec(dllexport) ClassDecl;
-class __declspec(dllexport) ClassDef { };
+class __declspec(dllexport) ClassDef {};
+
+template <typename T> class ClassTemplate {};
+
+template <typename T> class __declspec(dllexport) ExportedClassTemplate {};
+
+#ifdef MS
+// expected-note@+2{{class template 'ImportedClassTemplate' was declared 'dllimport' here}}
+#endif
+template <typename T> class __declspec(dllimport) ImportedClassTemplate {};
+
+// ClassTemplate<int> gets exported.
+class __declspec(dllexport) DerivedFromTemplate : public ClassTemplate<int> {};
+
+// ClassTemplate<int> is already exported.
+class __declspec(dllexport) DerivedFromTemplate2 : public ClassTemplate<int> {};
+
+// ExportedTemplate is already exported.
+class __declspec(dllexport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+
+#ifdef MS
+// expected-warning@+3{{propagating dll attribute to templated base class with different dll attribute is unsupported}}
+// expected-note@+2{{attribute is here}}
+#endif
+class __declspec(dllexport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<double>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template without dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class DerivedFromTemplateD : public ClassTemplate<double> {};
+class __declspec(dllexport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<bool>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template with different dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class __declspec(dllimport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+class __declspec(dllexport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+
//===----------------------------------------------------------------------===//
// Precedence
Index: test/SemaCXX/dllimport.cpp
===================================================================
--- test/SemaCXX/dllimport.cpp
+++ test/SemaCXX/dllimport.cpp
@@ -955,6 +955,46 @@
class __declspec(dllimport) ClassDef { };
+template <typename T> class ClassTemplate {};
+
+#ifdef MS
+// expected-note@+2{{class template 'ExportedClassTemplate' was declared 'dllexport' here}}
+#endif
+template <typename T> class __declspec(dllexport) ExportedClassTemplate {};
+
+template <typename T> class __declspec(dllimport) ImportedClassTemplate {};
+
+// ClassTemplate<int> gets imported.
+class __declspec(dllimport) DerivedFromTemplate : public ClassTemplate<int> {};
+
+// ClassTemplate<int> is already imported.
+class __declspec(dllimport) DerivedFromTemplate2 : public ClassTemplate<int> {};
+
+// ImportedTemplate is already imported.
+class __declspec(dllimport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+
+#ifdef MS
+// expected-warning@+3{{propagating dll attribute to templated base class with different dll attribute is unsupported}}
+// expected-note@+2{{attribute is here}}
+#endif
+class __declspec(dllimport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<double>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template without dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class DerivedFromTemplateD : public ClassTemplate<double> {};
+class __declspec(dllimport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<bool>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template with different dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class __declspec(dllexport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+class __declspec(dllimport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+
#ifdef MS
// expected-note@+5{{previous attribute is here}}
// expected-note@+4{{previous attribute is here}}
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