Add a fixit for attributes incorrectly placed prior to 'struct/class/enum' keyword.

Suggest moving the following erroneous attrib list (based on location)
[[]] struct X;  
to 
struct [[]] X;

Additionally, added a fixme for the current implementation that diagnoses misplaced attributes to consider using the newly introduced diagnostic (that I think is more user-friendly).

llvm-svn: 321449
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 9fe4309..2a99939 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -1548,15 +1548,21 @@
   SourceLocation Loc = Tok.getLocation();
   ParseCXX11Attributes(Attrs);
   CharSourceRange AttrRange(SourceRange(Loc, Attrs.Range.getEnd()), true);
-
+  // FIXME: use err_attributes_misplaced
   Diag(Loc, diag::err_attributes_not_allowed)
     << FixItHint::CreateInsertionFromRange(CorrectLocation, AttrRange)
     << FixItHint::CreateRemoval(AttrRange);
 }
 
-void Parser::DiagnoseProhibitedAttributes(ParsedAttributesWithRange &attrs) {
-  Diag(attrs.Range.getBegin(), diag::err_attributes_not_allowed)
-    << attrs.Range;
+void Parser::DiagnoseProhibitedAttributes(ParsedAttributesWithRange &attrs,
+                                          const SourceLocation CorrectLocation) {
+  if (CorrectLocation.isValid()) {
+    CharSourceRange AttrRange(attrs.Range, true);
+    Diag(CorrectLocation, diag::err_attributes_misplaced)
+        << FixItHint::CreateInsertionFromRange(CorrectLocation, AttrRange)
+        << FixItHint::CreateRemoval(AttrRange);
+  } else
+    Diag(attrs.Range.getBegin(), diag::err_attributes_not_allowed) << attrs.Range;
 }
 
 void Parser::ProhibitCXX11Attributes(ParsedAttributesWithRange &Attrs,