From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755169AbeD3WQq (ORCPT ); Mon, 30 Apr 2018 18:16:46 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:42536 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbeD3WQp (ORCPT ); Mon, 30 Apr 2018 18:16:45 -0400 X-Google-Smtp-Source: AB8JxZqhBlSdRTXTrO3xJsTw5EPow9RPX7AcCmP1U1ZfybhAj92hxhBGng+iIQ80zmKdhWHpBBp3jw== Date: Mon, 30 Apr 2018 15:16:43 -0700 From: Matthias Kaehlcke To: Chris Wilson Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Guenter Roeck , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [Intel-gfx] [PATCH v2] drm/i915: Disable some extra clang warnings Message-ID: <20180430221643.GD133494@google.com> References: <20180319191451.83910-1-mka@chromium.org> <20180430193119.GB133494@google.com> <152511850981.10429.1077865835761338509@mail.alporthouse.com> <20180430205145.GC133494@google.com> <152512211018.25556.5922164301972750801@mail.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <152512211018.25556.5922164301972750801@mail.alporthouse.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 30, 2018 at 10:01:50PM +0100, Chris Wilson wrote: > Quoting Matthias Kaehlcke (2018-04-30 21:51:45) > > On Mon, Apr 30, 2018 at 09:01:49PM +0100, Chris Wilson wrote: > > > Quoting Matthias Kaehlcke (2018-04-30 20:31:19) > > > > On Mon, Mar 19, 2018 at 12:14:51PM -0700, Matthias Kaehlcke wrote: > > > > > Commit 39bf4de89ff7 ("drm/i915: Add -Wall -Wextra to our build, set > > > > > warnings to full") enabled extra warnings for i915 to spot possible > > > > > bugs in new code, and then disabled a subset of these warnings to keep > > > > > the current code building without warnings (with gcc). Enabling the > > > > > extra warnings also enabled some additional clang-only warnings, as a > > > > > result building i915 with clang currently is extremely noisy. For now > > > > > also disable the clang warnings sign-compare, sometimes-uninitialized, > > > > > unneeded-internal-declaration and initializer-overrides. If desired > > > > > they can be re-enabled after the code has been fixed. > > > > > > > > > > Fixes: 39bf4de89ff7 ("drm/i915: Add -Wall -Wextra to our build, set > > > > > warnings to full") > > > > > > Do we need to backport this for a non-default build with a non-default > > > compiler? > > > > If it affected a LTS build I'd say yes, but since that isn't the case > > I think it's not necessary. > > > > > > > Signed-off-by: Matthias Kaehlcke > > > > > --- > > > > > Changes in v2: > > > > > - rebased on drm-tip > > > > > - added comment indicating that disabled warnings are clang warnings > > > > > > > > > > drivers/gpu/drm/i915/Makefile | 5 +++++ > > > > > 1 file changed, 5 insertions(+) > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile > > > > > index 4eee91a3a236..9717c037b582 100644 > > > > > --- a/drivers/gpu/drm/i915/Makefile > > > > > +++ b/drivers/gpu/drm/i915/Makefile > > > > > @@ -18,6 +18,11 @@ subdir-ccflags-y += $(call cc-disable-warning, type-limits) > > > > > subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers) > > > > > subdir-ccflags-y += $(call cc-disable-warning, implicit-fallthrough) > > > > > subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable) > > > > > +# clang warnings > > > > > +subdir-ccflags-y += $(call cc-disable-warning, sign-compare) > > > > > > Too much mixup in the code to be fixed overnight indeed. > > > > > > > > +subdir-ccflags-y += $(call cc-disable-warning, sometimes-uninitialized) > > > > > > Annoyingly it appears that clang has more false positives. > > > > > > > > +subdir-ccflags-y += $(call cc-disable-warning, unneeded-internal-declaration) > > > > > > Example? I don't recall this one, so don't know if we should just not > > > fix it rather than suppress. I've used ignored-attributes, perhaps that > > > was for the same cause. > > > > drivers/gpu/drm/i915/intel_guc_submission.c:183:13: warning: function > > 'has_doorbell' is not needed and will not be emitted > > [-Wunneeded-internal-declaration] > > static bool has_doorbell(struct intel_guc_client *client) > > > > The function is only called within a GEM_BUG_ON macro, which does not > > evaluate the expression unless CONFIG_DRM_I915_DEBUG_GEM is set. > > > > Instead of disabling the warning it would probably be better to mark > > has_doorbell as __maybe_unused. > > Hmm, if it is just this one, I would remove the use from > intel_guc_submission and move it into selftests/ > The single use case inside intel_guc_submission isn't that interesting > and I doubt we would miss not having the assert. Could you take care of this? I'm not really familiar with the i915 codebase and might not put it exactly where you want it ;-) I'd then rebase this patch and leave -Wunneeded-internal-declaration enabled. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Kaehlcke Subject: Re: [Intel-gfx] [PATCH v2] drm/i915: Disable some extra clang warnings Date: Mon, 30 Apr 2018 15:16:43 -0700 Message-ID: <20180430221643.GD133494@google.com> References: <20180319191451.83910-1-mka@chromium.org> <20180430193119.GB133494@google.com> <152511850981.10429.1077865835761338509@mail.alporthouse.com> <20180430205145.GC133494@google.com> <152512211018.25556.5922164301972750801@mail.alporthouse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-pg0-x243.google.com (mail-pg0-x243.google.com [IPv6:2607:f8b0:400e:c05::243]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1B6476E247 for ; Mon, 30 Apr 2018 22:16:44 +0000 (UTC) Received: by mail-pg0-x243.google.com with SMTP id i194-v6so7207298pgd.0 for ; Mon, 30 Apr 2018 15:16:44 -0700 (PDT) Content-Disposition: inline In-Reply-To: <152512211018.25556.5922164301972750801@mail.alporthouse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Chris Wilson Cc: David Airlie , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Rodrigo Vivi , Guenter Roeck List-Id: dri-devel@lists.freedesktop.org T24gTW9uLCBBcHIgMzAsIDIwMTggYXQgMTA6MDE6NTBQTSArMDEwMCwgQ2hyaXMgV2lsc29uIHdy b3RlOgo+IFF1b3RpbmcgTWF0dGhpYXMgS2FlaGxja2UgKDIwMTgtMDQtMzAgMjE6NTE6NDUpCj4g PiBPbiBNb24sIEFwciAzMCwgMjAxOCBhdCAwOTowMTo0OVBNICswMTAwLCBDaHJpcyBXaWxzb24g d3JvdGU6Cj4gPiA+IFF1b3RpbmcgTWF0dGhpYXMgS2FlaGxja2UgKDIwMTgtMDQtMzAgMjA6MzE6 MTkpCj4gPiA+ID4gT24gTW9uLCBNYXIgMTksIDIwMTggYXQgMTI6MTQ6NTFQTSAtMDcwMCwgTWF0 dGhpYXMgS2FlaGxja2Ugd3JvdGU6Cj4gPiA+ID4gPiBDb21taXQgMzliZjRkZTg5ZmY3ICgiZHJt L2k5MTU6IEFkZCAtV2FsbCAtV2V4dHJhIHRvIG91ciBidWlsZCwgc2V0Cj4gPiA+ID4gPiB3YXJu 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