From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail-wm1-f68.google.com (mail-wm1-f68.google.com [209.85.128.68])
 by mx.groups.io with SMTP id smtpd.web11.32705.1585210272193084010
 for <devel@edk2.groups.io>;
 Thu, 26 Mar 2020 01:11:12 -0700
Authentication-Results: mx.groups.io;
 dkim=pass header.i=@linaro.org header.s=google header.b=o4C0mptp;
 spf=pass (domain: linaro.org, ip: 209.85.128.68, mailfrom: ard.biesheuvel@linaro.org)
Received: by mail-wm1-f68.google.com with SMTP id a81so5907116wmf.5
        for <devel@edk2.groups.io>; Thu, 26 Mar 2020 01:11:11 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=linaro.org; s=google;
        h=mime-version:references:in-reply-to:from:date:message-id:subject:to
         :cc:content-transfer-encoding;
        bh=e6PkHkFfKiok10MNxhKRSSdHlm3oPFO/gSA97605D9k=;
        b=o4C0mptpYKPk8PdgPTcEYVFigwdcr16npc0v6ESTx+JTR/fjit3O5Q0dfBlxke8tH9
         lwwUuifg6vfcpKf9ywNBYJYZgfd+Gny6yFLUPTbDgKgNp1zEgljNGZYLmxMpd01BClNO
         LW1D17NPcWVqBQfBK1v7gPOjbDoNXxOtUEXJGcKJDrmxkH3/dK7nw2EL5EnJO5N79elX
         QTrMakxzA6x/1ScCLbGN3yawXc6rQ68nmWTbpafQB4ElnGHEvH0iUE/rWkUq6r6aYFi6
         a6thO9bs/bzFFuwQcfheC4JAQdlqP3jANMHYl5Facf2+orbRA1Znz3uPrUSPGXH9X2Ee
         DEeA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20161025;
        h=x-gm-message-state:mime-version:references:in-reply-to:from:date
         :message-id:subject:to:cc:content-transfer-encoding;
        bh=e6PkHkFfKiok10MNxhKRSSdHlm3oPFO/gSA97605D9k=;
        b=R1Y5uTVYFlJaLDpbzxqHdVbih2bTzAr6iNgXo7GrMl0o8QXsaEmXG2rTQBReus6kZr
         yYwCt/TMj9pSzsvYtG1G7pCP/uWrZ8feH8UBHveSc299YdZbp+sfIFDT2kyUfe5TcT4M
         O/57gOyqJWUMAe1EmS79uWpPDIvpltyIP5icTae5HpT7TCKAGYk5DITsxTG5RkD3QWWe
         iHHUG2NSo5XJfrWcqbdUV0aYyqwJlIEWTkaGTfTyCzg4p5hTZ2ylIBUTASki37ZCy3pV
         lZElfOQoV8nCJGTNVmMH7wv9g3O8SsEYKNuqy5cnfkps3bGYn8U+lNp0cQ6A+77HB6na
         2L2A==
X-Gm-Message-State: ANhLgQ3hdW6e5GTXpP/j82SUEU4uU2m7duDMNlt6bMJlPoaUfJqlJ9wS
	gWsYf/0eTMoc0tvyzgWBmwj39MUcPmy1CR/OtTaK6Q==
X-Google-Smtp-Source: ADFU+vu3jnlT3YGp3I1TVYfnmS5TiB6aBtyCx4Oq9pquSZ+S3KRqWAhVppt2qbMG5bVluo1miPwnfWjUMpA2I0gqhJw=
X-Received: by 2002:a7b:c050:: with SMTP id u16mr1974687wmc.68.1585210270772;
 Thu, 26 Mar 2020 01:11:10 -0700 (PDT)
MIME-Version: 1.0
References: <20200325091238.24048-1-ard.biesheuvel@linaro.org> <e789512c-372e-d972-2b14-1a67e77302ca@redhat.com>
In-Reply-To: <e789512c-372e-d972-2b14-1a67e77302ca@redhat.com>
From: "Ard Biesheuvel" <ard.biesheuvel@linaro.org>
Date: Thu, 26 Mar 2020 09:10:59 +0100
Message-ID: <CAKv+Gu_f5+N0fzTVqBMkNjSamiVYvwhbZf7xHq7HCRER4qrqvA@mail.gmail.com>
Subject: Re: [edk2-devel] [PATCH] OvmfPkg/X86QemuLoadImageLib: add dummy assignment to work around GCC
To: Laszlo Ersek <lersek@redhat.com>
Cc: edk2-devel-groups-io <devel@edk2.groups.io>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Wed, 25 Mar 2020 at 20:08, Laszlo Ersek <lersek@redhat.com> wrote:
>
> On 03/25/20 10:12, Ard Biesheuvel wrote:
> > GCC 4.8 or 4.9 may throw the following error when building OVMF:
> >
> >   Edk2/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c:
> >       In function =E2=80=98QemuLoadKernelImage=E2=80=99:
> >   Edk2/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c:416:30=
:
> >       error: =E2=80=98CommandLine=E2=80=99 may be used uninitialized in=
 this function
> >                                                [-Werror=3Dmaybe-uniniti=
alized]
> >         UnicodeSPrintAsciiFormat (
> >         cc1: all warnings being treated as errors
> >
> > This is due to the fact that older GCCs fail to infer that CommandLine =
is
> > never actually used unless it has been assigned. So add a redundant NUL=
L
> > assignment to help these older GCCs understand this.
> >
> > Link: https://bugzilla.tianocore.org/show_bug.cgi?id=3D2630
> > Fixes: 7c47d89003a6f ("OvmfPkg: implement QEMU loader library for X86 w=
ith ...")
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c =
b/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
> > index c5bd6862b265..52b14a4462d8 100644
> > --- a/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
> > +++ b/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
> > @@ -291,6 +291,11 @@ QemuLoadKernelImage (
> >    CHAR8                     *CommandLine;
> >    UINTN                     InitrdSize;
> >
> > +  //
> > +  // Redundant assignment to work around GCC48/GCC49 limitations.
> > +  //
> > +  CommandLine =3D NULL;
> > +
> >    //
> >    // Load the image. This should call back into the QEMU EFI loader fi=
le system.
> >    //
> >
>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>

Pushed, thanks.