From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,fb264cdd67c2f20f X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news4.google.com!news3.google.com!news.glorb.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Alex R. Mosteo" Newsgroups: comp.lang.ada Subject: Re: Compiler Bug or what I'm doing wrong? Date: Wed, 21 Jun 2006 14:46:53 +0200 Message-ID: <4fstb4F1kgmekU1@individual.net> References: <05lkrrojfd.fsf@hod.lan.m-e-leypold.de> <1150875880.103859.95200@p79g2000cwp.googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7Bit X-Trace: individual.net VdMgUDd5gZ2wL8yRL1r1ygXaYosJfsl9YmA1/2CCwUJOzwHQ4= User-Agent: KNode/0.10.2 Xref: g2news2.google.com comp.lang.ada:4875 Date: 2006-06-21T14:46:53+02:00 List-Id: M E Leypold wrote: > > "Ludovic Brenta" writes: > >> M E Leypold writes : >> > I've generated a core and also can reproduce the SIGSEGV in this >> > configuration 100% of the time. Don't hesitate to ask for more >> > debugger output or more code. >> >> I'd ask for *less* code :-) >> >> It would be nice if you could write a minimal test case that reproduces >> the problem. Yes, it takes time. I cannot do that for you, for various > > I've already done that (it took me 10 hours so far to isolate the > problem from a larger program): The original program was much > larger. I'll be trying to even strip the example furter, but the > problem with the bug seems to be that it's a Heisenbug which vanishes > when you delete some fields in the datastructure, then turns up again > if you delete more fields and so on. The malloc() implementation of > libc which the GNAt runtime uses is unchecked so obviously one gets > sometimes away when freeing unvalid pointers and (as we know from C > programming). Indeed, for me the most frustrating part of bug reporting is obtaining a sufficiently small test case. I usually hit bugs in a large project I'm involved. Once you start to chop off, you know that the bug will disappear along the way. When you're not even sure if you're the culprit and not the compiler, the frustration is even bigger. I'm now, for example, facing a spurious exception case when switching from GNAT GPL'05 to GPL'06, only when certain compiler switches are used. I have already found a workaround, and I even know that the problem is related with interfaces, but I fear that the effort to isolate it will be a waste of time. So the temptation to move on is big... This post is really just to show my "condolences" and support. Best luck, A. Mosteo.