initial support for recognizing __transparent_union__ attributes

comments on the ML will follow

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@50262 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 30 insertions, 0 deletions

diff --git a/lib/Parse/AttributeList.cpp b/lib/Parse/AttributeList.cpp
index c764085caa..2d8de97f3c 100644
--- a/lib/Parse/AttributeList.cpp
+++ b/lib/Parse/AttributeList.cpp
@@ -90,6 +90,9 @@ AttributeList::Kind AttributeList::getKind(const IdentifierInfo *Name) {
   case 15:
     if (!memcmp(Str, "ext_vector_type", 15)) return AT_ext_vector_type;
     break;
+  case 17:
+    if (!memcmp(Str, "transparent_union", 17)) return AT_transparent_union;
+    break;
   case 18:
     if (!memcmp(Str, "warn_unused_result", 18)) return AT_warn_unused_result;
     break;
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 4b6722abc6..33d3ce4ece 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -323,6 +323,7 @@ private:
   void HandleFormatAttribute(Decl *d, AttributeList *rawAttr);
   void HandleStdCallAttribute(Decl *d, AttributeList *rawAttr);
   void HandleFastCallAttribute(Decl *d, AttributeList *rawAttr);
+  void HandleTransparentUnionAttribute(Decl *d, AttributeList *rawAttr);
   
   void WarnUndefinedMethod(SourceLocation ImpLoc, ObjCMethodDecl *method,
                            bool &IncompleteImpl);
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index c97ecc8313..373aaceb87 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2003,6 +2003,9 @@ void Sema::HandleDeclAttribute(Decl *New, AttributeList *Attr) {
   case AttributeList::AT_format:
     HandleFormatAttribute(New, Attr);
     break;
+  case AttributeList::AT_transparent_union:
+    HandleTransparentUnionAttribute(New, Attr);
+    break;
   default:
 #if 0
     // TODO: when we have the full set of attributes, warn about unknown ones.
@@ -2419,6 +2422,29 @@ void Sema::HandleFormatAttribute(Decl *d, AttributeList *rawAttr) {
                             Idx.getZExtValue(), FirstArg.getZExtValue()));
 }
 
+void Sema::HandleTransparentUnionAttribute(Decl *d, AttributeList *rawAttr) {
+  // check the attribute arguments.
+  if (rawAttr->getNumArgs() != 0) {
+    Diag(rawAttr->getLoc(), diag::err_attribute_wrong_number_arguments,
+         std::string("0"));
+    return;
+  }
+
+  TypeDecl *decl = dyn_cast<TypeDecl>(d);
+
+  if (!decl || !Context.getTypeDeclType(decl)->isUnionType()) {
+    Diag(rawAttr->getLoc(), diag::warn_attribute_wrong_decl_type,
+         "transparent_union", "union");
+    return;
+  }
+
+  QualType QTy = Context.getTypeDeclType(decl);
+  const RecordType *Ty = QTy->getAsUnionType();
+
+// FIXME
+// Ty->addAttr(new TransparentUnionAttr());
+}
+
 void Sema::HandleAnnotateAttribute(Decl *d, AttributeList *rawAttr) {
   // check the attribute arguments.
   if (rawAttr->getNumArgs() != 1) {