From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32566 invoked by alias); 11 Apr 2014 20:16:39 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 32552 invoked by uid 89); 11 Apr 2014 20:16:38 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-qg0-f53.google.com Received: from mail-qg0-f53.google.com (HELO mail-qg0-f53.google.com) (209.85.192.53) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Fri, 11 Apr 2014 20:16:37 +0000 Received: by mail-qg0-f53.google.com with SMTP id f51so5140780qge.40 for ; Fri, 11 Apr 2014 13:16:34 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.140.87.151 with SMTP id r23mr30300073qgd.75.1397247394834; Fri, 11 Apr 2014 13:16:34 -0700 (PDT) Received: by 10.140.30.74 with HTTP; Fri, 11 Apr 2014 13:16:34 -0700 (PDT) In-Reply-To: References: Date: Fri, 11 Apr 2014 20:16:00 -0000 Message-ID: Subject: Re: [patch] Fix unused static symbols so they're not dropped by clang From: David Blaikie To: Doug Evans Cc: gdb-patches , Eric Christopher Content-Type: text/plain; charset=ISO-8859-1 X-IsSubscribed: yes X-SW-Source: 2014-04/txt/msg00219.txt.bz2 On Fri, Apr 11, 2014 at 12:32 PM, Doug Evans wrote: > On Fri, Apr 11, 2014 at 11:23 AM, Doug Evans wrote: >> On Thu, Apr 10, 2014 at 11:51 PM, David Blaikie wrote: >>> Several tests used file-static functions and variables that were not >>> referenced by the code. Even at -O0, clang omits these entities at the >>> frontend so the tests fail. >>> >>> Since it doesn't look like these tests needed this functionality for >>> what they were testing, I've modified the variables/functions to >>> either be non-static, or marked them with __attribute__((used)). >>> >>> If it's preferred that I use the attribute more pervasively, rather >>> than just making the entities non-static, I can provide a patch for >>> that (or some other preferred solution). There's certainly precedent >>> for both (non-static entities and __attribute__((used)) in the >>> testsuite already and much more of the former than the latter). >>> >>> I have commit-after-review access, so just looking for sign-off here. >> >> Yikes. >> >> This is becoming more and more painful (not your fault of course!). >> I can imagine this being a never ending source of regressions. >> >> Does clang perchance have a -O0-and-yes-I-really-mean-O0 option? > > Failing that, > > making the entries non-static without adding a comment to explain why > things are the way they are will leave things in a more fragile state, If people only ever test with GCC, yes. Though to a degree I'm happy enough carrying the burden of providing patches to cleanup test cases people commit that break clang. We're going to do this anyway for other sources of breakage, I don't /think/ this particular kind of breakage would be especially more egregious (possibly more common, but providing a patch every few months doesn't sound like the end of the world to me) Though I agree that it's slightly subtle to make them non-static with no comment. > and if we're going to add a comment we might just as well use an > attribute throughout I guess. > However using the attribute is, technically, more complicated than > that because we shouldn't unnecessarily break testing with other > compilers. While some test cases use #ifdefs, there are several test cases that already use __attribute__((used)) unconditionally... so I'm not sure if there's a problem adding more. But perhaps I misunderstand the priority/need here. > That suggests putting the attribute in a macro in a header protected > by appropriate #ifdefs. > The testsuite doesn't yet have a single location for such headers > (testsuite/include or some such, though there is already testsuite/lib > (cough) but if it's just for the one header ...).