How to determine if a decl is a class member in GCC

["Le-Chun Wu" <lcwu at google dot com>]

Hi,

In my attribute handlers that handle the new thread-safety attributes
(in c-common.c), I need to check if a decl is a class member. How do
people do that? My original code was checking if a decl is a
FIELD_DECL but that doesn't work for static members. I also tried to
use DECL_CONTEXT but it is not set (in the C++ front-end) for data
members. (I was able to use DECL_CONTEXT for member functions,
though.) Is there any other way that I should use?

BTW, as an experiment, I went ahead and made the following change in
C++ front-end to set the DECL_CONTEXT of class data members. The patch
appears to work and doesn't seem to break any g++ and gcc regression
tests. (I will be running gdb testsuite later.) I think there must be
a reason why the DECL_CONTEXT of data members wasn't set in the
front-end, but it's not clear to my why. Can someone kindly explain
why that is and whether the patch is OK?

Thanks,

Le-chun


Index: cp/decl.c
===================================================================
--- cp/decl.c   (revision 137849)
+++ cp/decl.c   (working copy)
@@ -9074,6 +9074,11 @@ grokdeclarator (const cp_declarator *dec

               if (thread_p)
                 DECL_TLS_MODEL (decl) = decl_default_tls_model (decl);
+
+                /* Since a static class data member is a VAR_DECL (instead of
+                   a FIELD_DECL), setting the decl_context here allows us to
+                   tell if it is a class member.  */
+                DECL_CONTEXT (decl) = ctype ? ctype : current_class_type;
             }
           else
             {