From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: "Carlo Marcelo Arenas Belón" <carenas@gmail.com>
Cc: git@vger.kernel.org, t.gummerer@gmail.com, pclouds@gmail.com,
jonathantanmy@google.com
Subject: Re: [PATCH 2/3] Makefile: avoid multiple -Wall in CFLAGS
Date: Tue, 28 Sep 2021 11:19:24 +0200 [thread overview]
Message-ID: <87wnn1vxh8.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <20210928091054.78895-3-carenas@gmail.com>
On Tue, Sep 28 2021, Carlo Marcelo Arenas Belón wrote:
> 6163f3f1a4 (config.mak.dev: add -Wall, primarily for -Wformat, to help
> autoconf users, 2018-10-12) adds a second -Wall in config.mak.dev to
> workaround the lack of one from config.mak.autogen.
>
> Since 6d5d4b4e93 (Makefile: allow for combining DEVELOPER=1 and
> CFLAGS="...", 2019-02-22), that variable is set instead as part of
> DEVELOPER_FLAGS which won't be overriden by config.mak.autogen, so
> it can be safely removed from config.mak.dev if set instead in the
> Makefile.
>
> This also has the advantage of separating cleanly CFLAGS which are
> used for building with the ones that provide with diagnostics.
>
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
> ---
> Makefile | 3 ++-
> config.mak.dev | 1 -
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 9df565f27b..963b9e7c6b 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1200,7 +1200,8 @@ endif
> # Set CFLAGS, LDFLAGS and other *FLAGS variables. These might be
> # tweaked by config.* below as well as the command-line, both of
> # which'll override these defaults.
> -CFLAGS = -g -O2 -Wall
> +CFLAGS = -g -O2
> +DEVELOPER_CFLAGS = -Wall
> LDFLAGS =
> CC_LD_DYNPATH = -Wl,-rpath,
> BASIC_CFLAGS = -I.
> diff --git a/config.mak.dev b/config.mak.dev
> index c81be62a5c..90c47d2782 100644
> --- a/config.mak.dev
> +++ b/config.mak.dev
> @@ -6,7 +6,6 @@ ifeq ($(filter no-error,$(DEVOPTS)),)
> DEVELOPER_CFLAGS += -Werror
> SPARSE_FLAGS += -Wsparse-error
> endif
> -DEVELOPER_CFLAGS += -Wall
> ifeq ($(filter no-pedantic,$(DEVOPTS)),)
> DEVELOPER_CFLAGS += -pedantic
> ifneq ($(filter clang4 gcc5,$(COMPILER_FEATURES)),)
This really breaks things for anyone who's relying on specifing CFLAGS
now to clobber the default -Wall configuration, e.g. on both xlc and aCC
after this:
xlc: 1501-289 (W) Option -Wall was incorrectly specified. The option will be ignored.
cc: error 1914: bad form for `-W' option
I.e. they didn't work before, but I've got CFLAGS="-g -O0" for both in
my build scripts, so they didn't get -Wall before, but now they do, so
I'll need:
CFLAGS=<that> DEVELOPER_CFLAGS=
And in my own dev setup I do in config.mak: "CFLAGS=-g -O0", and then
rely on config.mak.dev to set -Wall, but if I did e.g.:
DEVELOPER= CFLAGS="-g -O0 -Wall"
I'd end up with -Wall twice, gcc doesn't complain, but maybe some other
toolchains do.
For the former case this seems like a really odd and leaky interface
since I don't have DEVELOPER=1. Let's leave DEVOPTS, DEVELOPER_CFLAGS
etc. etc. only in effect for anyone who turns on that option.
Anyway, I don't think it's a no-go to make a change in this direction,
and while it would break builds for some perhaps the end result is worth
it. I haven't really looked closely enough at the Makefile logic you're
untangling to form an opinion on it.
But I think this needs to at least have
s/DEVELOPER_CFLAGS/WARNING_CFLAGS/g or something.
But not to saddle you with an impossible task, wouldn't this whole thing
be much easier if we included config.mak* before setting our own CFLAGS
etc. defaults? But of course that would break for anyone relying on "+="
working, so I don't know.
next prev parent reply other threads:[~2021-09-28 9:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-28 9:10 [PATCH 0/3] Makefile: tighten pedantic flag Carlo Marcelo Arenas Belón
2021-09-28 9:10 ` [PATCH 1/3] Makefile: restrict -Wpedantic and -Wno-pedantic-ms-format better Carlo Marcelo Arenas Belón
2021-09-28 11:46 ` Ævar Arnfjörð Bjarmason
2021-09-28 23:39 ` Junio C Hamano
2021-09-28 9:10 ` [PATCH 2/3] Makefile: avoid multiple -Wall in CFLAGS Carlo Marcelo Arenas Belón
2021-09-28 9:19 ` Ævar Arnfjörð Bjarmason [this message]
2021-09-28 11:03 ` Carlo Arenas
2021-09-28 21:19 ` Junio C Hamano
2021-09-28 23:22 ` Carlo Arenas
2021-09-29 4:08 ` Junio C Hamano
2021-09-28 9:10 ` [PATCH 3/3] config.mak.dev: simplify compiler check for multiple compilers Carlo Marcelo Arenas Belón
2021-09-28 12:07 ` Ævar Arnfjörð Bjarmason
2021-09-28 21:30 ` Junio C Hamano
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