__uuidof() and declspec(uuid("...")) should be allowed on enumeration types

Although not specifically mentioned in the documentation, MSVC accepts
__uuidof(…) and declspec(uuid("…")) attributes on enumeration types in
addition to structs/classes. This is meaningful, as such types *do* have
associated UUIDs in ActiveX typelibs, and such attributes are included
by default in the wrappers generated by their #import construct, so they
are not particularly unusual.

clang currently rejects the declspec with a –Wignored-attributes
warning, and errors on __uuidof() with “cannot call operator __uuidof on
a type with no GUID” (because it rejected the uuid attribute, and
therefore finds no value). This is causing problems for us while trying
to use clang-tidy on a codebase that makes heavy use of ActiveX.

I believe I have found the relevant places to add this functionality,
this patch adds this case to clang’s implementation of these MS
extensions.  patch is against r285994 (or actually the git mirror
80464680ce).

Both include an update to test/Parser/MicrosoftExtensions.cpp to
exercise the new functionality.

This is my first time contributing to LLVM, so if I’ve missed anything
else needed to prepare this for review just let me know!

__uuidof: https://msdn.microsoft.com/en-us/library/zaah6a61.aspx
declspec(uuid("…")): https://msdn.microsoft.com/en-us/library/3b6wkewa.aspx
 #import: https://msdn.microsoft.com/en-us/library/8etzzkb6.aspx

Reviewers: aaron.ballman, majnemer, rnk

Differential Revision: https://reviews.llvm.org/D26846

llvm-svn: 289567

diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 4692495..4c8276a 100644 (file)
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -1618,7 +1618,9 @@ def Used : InheritableAttr {
 def Uuid : InheritableAttr {
   let Spellings = [Declspec<"uuid">, Microsoft<"uuid">];
   let Args = [StringArgument<"Guid">];
-//  let Subjects = SubjectList<[CXXRecord]>;
+  let Subjects = SubjectList<[Record, Enum], WarnDiag, "ExpectedEnumOrClass">;
+  // FIXME: Allow expressing logical AND for LangOpts. Our condition should be:
+  // CPlusPlus && (MicrosoftExt || Borland)
   let LangOpts = [MicrosoftExt, Borland];
   let Documentation = [Undocumented];
 }

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index cc8d5d4..8498740 100644 (file)
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2650,7 +2650,8 @@ def warn_attribute_wrong_decl_type : Warning<
   "|variables, enums, fields and typedefs"
   "|functions, methods, enums, and classes"
   "|structs, classes, variables, functions, and inline namespaces"
-  "|variables, functions, methods, types, enumerations, enumerators, labels, and non-static data members}1">,
+  "|variables, functions, methods, types, enumerations, enumerators, labels, and non-static data members"
+  "|classes and enumerations}1">,
   InGroup<IgnoredAttributes>;
 def err_attribute_wrong_decl_type : Error<warn_attribute_wrong_decl_type.Text>;
 def warn_type_attribute_wrong_type : Warning<

diff --git a/clang/include/clang/Sema/AttributeList.h b/clang/include/clang/Sema/AttributeList.h
index 0c56b3f..e74bf6a 100644 (file)
--- a/clang/include/clang/Sema/AttributeList.h
+++ b/clang/include/clang/Sema/AttributeList.h
@@ -925,7 +925,8 @@ enum AttributeDeclKind {
   ExpectedVariableEnumFieldOrTypedef,
   ExpectedFunctionMethodEnumOrClass,
   ExpectedStructClassVariableFunctionOrInlineNamespace,
-  ExpectedForMaybeUnused
+  ExpectedForMaybeUnused,
+  ExpectedEnumOrClass,
 };
 
 }  // end namespace clang

diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index ffb1051..2ecea5f 100644 (file)
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -4666,12 +4666,6 @@ static void handleUuidAttr(Sema &S, Decl *D, const AttributeList &Attr) {
     return;
   }
 
-  if (!isa<CXXRecordDecl>(D)) {
-    S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
-      << Attr.getName() << ExpectedClass;
-    return;
-  }
-
   StringRef StrRef;
   SourceLocation LiteralLoc;
   if (!S.checkStringLiteralArgumentAttr(Attr, 0, StrRef, &LiteralLoc))

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 6acbd74..a4546ce 100644 (file)
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -520,17 +520,17 @@ getUuidAttrOfType(Sema &SemaRef, QualType QT,
   else if (QT->isArrayType())
     Ty = Ty->getBaseElementTypeUnsafe();
 
-  const auto *RD = Ty->getAsCXXRecordDecl();
-  if (!RD)
+  const auto *TD = Ty->getAsTagDecl();
+  if (!TD)
     return;
 
-  if (const auto *Uuid = RD->getMostRecentDecl()->getAttr<UuidAttr>()) {
+  if (const auto *Uuid = TD->getMostRecentDecl()->getAttr<UuidAttr>()) {
     UuidAttrs.insert(Uuid);
     return;
   }
 
   // __uuidof can grab UUIDs from template arguments.
-  if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(RD)) {
+  if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(TD)) {
     const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
     for (const TemplateArgument &TA : TAL.asArray()) {
       const UuidAttr *UuidForTA = nullptr;

diff --git a/clang/test/Parser/MicrosoftExtensions.cpp b/clang/test/Parser/MicrosoftExtensions.cpp
index 4aba8f0..830412e 100644 (file)
--- a/clang/test/Parser/MicrosoftExtensions.cpp
+++ b/clang/test/Parser/MicrosoftExtensions.cpp
@@ -65,6 +65,12 @@ struct_with_uuid2;
 struct
 struct_with_uuid2 {} ;
 
+enum __declspec(uuid("000000A0-0000-0000-C000-000000000046"))
+enum_with_uuid { };
+enum enum_without_uuid { };
+
+int __declspec(uuid("000000A0-0000-0000-C000-000000000046")) inappropriate_uuid; // expected-warning {{'uuid' attribute only applies to classes and enumerations}}
+
 int uuid_sema_test()
 {
    struct_with_uuid var_with_uuid[1];
@@ -81,6 +87,15 @@ int uuid_sema_test()
    __uuidof(const struct_with_uuid[1][1]);
    __uuidof(const struct_with_uuid*[1][1]); // expected-error {{cannot call operator __uuidof on a type with no GUID}}
 
+   __uuidof(enum_with_uuid);
+   __uuidof(enum_without_uuid); // expected-error {{cannot call operator __uuidof on a type with no GUID}}
+   __uuidof(enum_with_uuid*);
+   __uuidof(enum_without_uuid*); // expected-error {{cannot call operator __uuidof on a type with no GUID}}
+   __uuidof(enum_with_uuid[1]);
+   __uuidof(enum_with_uuid*[1]); // expected-error {{cannot call operator __uuidof on a type with no GUID}}
+   __uuidof(const enum_with_uuid[1][1]);
+   __uuidof(const enum_with_uuid*[1][1]); // expected-error {{cannot call operator __uuidof on a type with no GUID}}
+
    __uuidof(var_with_uuid);
    __uuidof(var_without_uuid);// expected-error {{cannot call operator __uuidof on a type with no GUID}}
    __uuidof(var_with_uuid[1]);