From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22403 invoked by alias); 7 Apr 2011 15:49:45 -0000 Received: (qmail 22392 invoked by uid 22791); 7 Apr 2011 15:49:43 -0000 X-SWARE-Spam-Status: No, hits=-2.8 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 07 Apr 2011 15:49:39 +0000 From: "davek at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug lto/48447] LTO link fails to link libgcc correctly when -nostdlib option is specified X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: lto X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: davek at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Thu, 07 Apr 2011 15:49:00 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2011-04/txt/msg00748.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48447 --- Comment #5 from Dave Korn 2011-04-07 15:49:29 UTC --- Well, this is basically a weakness in the pass-through solution implemented for PR 42690; it only knows about the compilers stdlibs, and doesn't process any user-specified libs on the command line. In the general case that's how things ought to be: LTRANS only generates new references to builtins/libcalls, not any of the user's code. However when you use -nostdlib and pass libgcc as if it were a user library, as in case 3, the pass-through mechanism doesn't know that it's actually a compiler runtime rather than user library and doesn't pass it through. The correct fix is going to be in the linker, not the compiler, by implementing a second library scan pass and obsoleting the pass-through mechanism. I've got a revised version of that experimental patch that I'll attach to this PR for reference.