From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30602 invoked by alias); 6 May 2018 01:31:11 -0000 Mailing-List: contact libffi-discuss-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libffi-discuss-owner@sourceware.org Received: (qmail 29382 invoked by uid 89); 6 May 2018 01:30:26 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,TIME_LIMIT_EXCEEDED autolearn=unavailable version=3.3.2 spammy=visual, filed, H*c:alternative, c X-HELO: mail-lf0-f66.google.com Received: from mail-lf0-f66.google.com (HELO mail-lf0-f66.google.com) (209.85.215.66) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sun, 06 May 2018 01:30:09 +0000 Received: by mail-lf0-f66.google.com with SMTP id u21-v6so35846315lfu.9 for ; Sat, 05 May 2018 18:30:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=OboTBNA38yBq+Nr6NiNtU/R+dfuL/BG8Zvpvav6LjDo=; b=gTo/TWVMPS9CLyHUHrtw0agGKo0hinT4lpzDvWgeQ7339+LdQ2vnXNxPauoJNH3zNw yenwM2pU7WkRJp5gdU2wLFZhvahUUliw91FhdZKgXZdinNi/LeZyXCPb5wXBhobEplT7 G9HRIBNYJkh1wG5XEne0Gt7fFnezYsp6NMEd7lqwqi6yrdlApFvRL73FFGgWSc0//WrR o9JSnxZ/LMvMuAdB0DXrnJYKOu3YsITeTXlezZjnBnwSJ8Fdr0WpffeIQIBGa6dSPw/q Uk5/8YTeZ1SPcyrIL/HCPlnAlbM7siTecq/jjJpaH6adF/w17zbKz+O+9du1hZ3Gu8AF CI5w== X-Gm-Message-State: ALQs6tBnj6qFiw4dbNUHA8C+Y+ueiCytOYBehjIA6Ps0QTJZD5hnOqj+ JgTE2HoQ6h9y7Q0S3PnHq2dC5IEp1nHSeh5eb9YL/Q== X-Google-Smtp-Source: AB8JxZoXX5onuF3tnLX93URl5TcNbGpUYu8Zp5emOgTRFDVwCwc9ecuPZlAq28NPOLJOTn2He8eqeA/27ba0SUmKY/U= X-Received: by 2002:a19:bec3:: with SMTP id o186-v6mr21303731lff.20.1525570207502; Sat, 05 May 2018 18:30:07 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a19:df46:0:0:0:0:0 with HTTP; Sat, 5 May 2018 18:30:06 -0700 (PDT) In-Reply-To: <95c5ed34fcb8394f33e67ac6f65a3cce@mail.kylheku.com> References: <95c5ed34fcb8394f33e67ac6f65a3cce@mail.kylheku.com> From: Anthony Green Date: Sun, 06 May 2018 01:31:00 -0000 Message-ID: Subject: Re: libffi trunk: new regressions on x86_64-linux-gnu, some test failures left on i686-linux-gnu To: "Kaz Kylheku (libffi)" <382-725-6798@kylheku.com> Cc: Matthias Klose , libffi-discuss@sourceware.org, "H.J. Lu" Content-Type: text/plain; charset="UTF-8" X-IsSubscribed: yes X-SW-Source: 2018/txt/msg00031.txt.bz2 On Sat, May 5, 2018 at 10:36 AM, Kaz Kylheku (libffi) < 382-725-6798@kylheku.com> wrote: > On 2018-05-05 06:51, Anthony Green wrote: > >> These failures are showing up because we're testing the microsoft ABI now. >> >> This looks like a bug in GCC. It's not returning small structures with >> floating point values in the right registers when following the Microsoft >> ABI. I'm going to figure out how to 'xfail' those tests and open a bug >> against GCC. Clang appears to get it right. >> > > When would this be an actual issue? > As far as I know this is the first time this bug has been reported. I've filed it here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43869 GCC is internally consistant, but can't generate code that will interface correctly to binaries built with clang or visual c. Since nobody has reported this problem before, I'm OK with having libffi follow the correct ABI as long as the GCC hackers agree to fix this in future versions of GCC. Libffi won't work with GCC-compiled ms_abi functions returning short structs (8 bytes or less) containing floating point values (a pretty narrow use-case!). This is why I'll just xfail the problematic test cases when we know we're using GCC. AG