Use attributes from the definition (if available) when
instantiating functions.

Fixes PR10272.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134491 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 0a05d0e..29385e5 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -59,7 +59,7 @@
 
 // FIXME: Is this still too simple?
 void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
-                            Decl *Tmpl, Decl *New) {
+                            const Decl *Tmpl, Decl *New) {
   for (AttrVec::const_iterator i = Tmpl->attr_begin(), e = Tmpl->attr_end();
        i != e; ++i) {
     const Attr *TmplAttr = *i;
@@ -2283,7 +2283,12 @@
                                                  EPI));
   }
 
-  SemaRef.InstantiateAttrs(TemplateArgs, Tmpl, New);
+  const FunctionDecl* Definition = Tmpl;
+
+  // Get the definition. Leaves the variable unchanged if undefined.
+  Tmpl->isDefined(Definition);
+
+  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New);
 
   return false;
 }