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Re: [C PATCH] Make attributes accept enum values (PR c/50459)
- From: Marc Glisse <marc dot glisse at inria dot fr>
- To: Marek Polacek <polacek at redhat dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Jason Merrill <jason at redhat dot com>, "Joseph S. Myers" <joseph at codesourcery dot com>
- Date: Mon, 14 Apr 2014 17:26:03 +0200 (CEST)
- Subject: Re: [C PATCH] Make attributes accept enum values (PR c/50459)
- Authentication-results: sourceware.org; auth=none
- References: <20140414151045 dot GA20332 at redhat dot com>
On Mon, 14 Apr 2014, Marek Polacek wrote:
Currently it is not possible to use an enum value (or const int in
C++) as an attribute argument (where compiler wants INTEGER_CST). This
is because the values are represented by CONST_DECL nodes -- and
we don't deal with them. I think it's viable to accept them too,
and that is what this patch does along with some clean ups.
Thanks.
+/* Perform default promotions or extract the integer constant from
+ an enum value. This function is used for getting a value from
+ an attribute argument. */
+
+static tree
+get_attrib_value (tree val)
+{
+ if (val
+ && TREE_CODE (val) != IDENTIFIER_NODE
+ && TREE_CODE (val) != FUNCTION_DECL)
+ val = default_conversion (val);
+ else if (TREE_CODE (val) == IDENTIFIER_NODE)
+ {
+ tree t = lookup_name (val);
+ if (t && TREE_CODE (t) == CONST_DECL)
+ return DECL_INITIAL (t);
+ }
+ return val;
+}
If val is NULL, it seems you still end up looking at its TREE_CODE?
(don't know if that can happen)
In C++, default_conversion probably handles IDENTIFIER_NODE just fine, but
having different code for the 2 languages would not be nice, right?
--
Marc Glisse