From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-440655-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 28720 invoked by alias); 17 Jan 2014 05:05:21 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Received: (qmail 28675 invoked by uid 48); 17 Jan 2014 05:05:14 -0000
From: "hpa at zytor dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/59850] New: Support sparse-style pointer address spaces (type attributes)
Date: Fri, 17 Jan 2014 05:05:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c
X-Bugzilla-Version: unknown
X-Bugzilla-Keywords:
X-Bugzilla-Severity: enhancement
X-Bugzilla-Who: hpa at zytor dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter
Message-ID: <bug-59850-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-01/txt/msg01797.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59850

            Bug ID: 59850
           Summary: Support sparse-style pointer address spaces (type
                    attributes)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hpa at zytor dot com

The sparse C compile checker has a set of extensions to the gcc type attribute
set:

__attribute__((noderef))

__attribute__((address_space(N)))

... where N is an arbitrary integer.

sparse will warn if pointers tagged with different address spaces are mixed,
and if a pointer tagged with "noderef" is dereferenced.

It would be highly useful if these protections could be extended to gcc itself
and thus get more ubiquitously run.  The main use case, of course, is the Linux
kernel, but almost any low-level application which has to deal with multiple
"manually maintained" address spaces is likely to benefit.

__attribute__((force))

... usually used as part of a cast, is used to suppress the warning.