From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rock.gnat.com (rock.gnat.com [IPv6:2620:20:4000:0:a9e:1ff:fe9b:1d1]) by sourceware.org (Postfix) with ESMTP id 02E77388703E for ; Tue, 5 Jan 2021 13:09:58 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 02E77388703E Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=oliva@adacore.com Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id AA5BF11758F; Tue, 5 Jan 2021 08:09:57 -0500 (EST) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id u7KXXZpny2KL; Tue, 5 Jan 2021 08:09:57 -0500 (EST) Received: from free.home (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by rock.gnat.com (Postfix) with ESMTPS id 69BF8117417; Tue, 5 Jan 2021 08:09:57 -0500 (EST) Received: from livre (livre.home [172.31.160.2]) by free.home (8.15.2/8.15.2) with ESMTPS id 105D9oQZ414454 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 5 Jan 2021 10:09:51 -0300 From: Alexandre Oliva To: Bernd Edlinger Cc: "gcc-patches\@gcc.gnu.org" , Richard Biener , Jakub Jelinek Subject: Re: [PATCH] Add line debug info for virtual thunks (PR ipa/97937) Organization: Free thinker, does not speak for AdaCore References: Errors-To: aoliva@lxoliva.fsfla.org Date: Tue, 05 Jan 2021 10:09:50 -0300 In-Reply-To: (Bernd Edlinger's message of "Mon, 4 Jan 2021 21:06:34 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 X-Spam-Status: No, score=-5.9 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Jan 2021 13:09:59 -0000 On Jan 4, 2021, Bernd Edlinger wrote: > currently there is a problem when debugging a virtual thunk. That is > a decl with DECL_IGNORED_P. Currently the line information displayed > in gdb is completely bogus, thus the last line of whatever function > is immediately before the PC of the thunk. *nod*, I recall seeing such issues before, for compiler-generated functions. Ideally, there should be some .noloc directive in the assembler that would signal "no line number info for this code fragment", but I don't think we have anything like that. I don't recall whether using compiler-generated line number programs avoids the problem, but I do recall that -ffunction-sections works around it, because IIRC switching to a new section has the same effect of discontinuing the line number program that the desired .noloc directive would. -- Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ Free Software Activist GNU Toolchain Engineer Vim, Vi, Voltei pro Emacs -- GNUlius Caesar