From: Junio C Hamano <gitster@pobox.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: "Carlo Marcelo Arenas Belón" <carenas@gmail.com>,
git@vger.kernel.org, t.gummerer@gmail.com, pclouds@gmail.com,
jonathantanmy@google.com
Subject: Re: [PATCH 3/3] config.mak.dev: simplify compiler check for multiple compilers
Date: Tue, 28 Sep 2021 14:30:02 -0700 [thread overview]
Message-ID: <xmqq4ka4jsmd.fsf@gitster.g> (raw)
In-Reply-To: <87k0j0x5mg.fsf@evledraar.gmail.com> ("Ævar Arnfjörð Bjarmason"'s message of "Tue, 28 Sep 2021 14:07:09 +0200")
Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> Anyway, feel free to ignore the below, and I think it's certainly not
> needed for this series, just my 0.02 if you're eventually refactoring
> some of this.
>
> diff --git a/config.mak.dev b/config.mak.dev
> index 0a87d8cbe9d..df27340b4b0 100644
> --- a/config.mak.dev
> +++ b/config.mak.dev
> @@ -2,6 +2,14 @@ ifndef COMPILER_FEATURES
> COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
> endif
>
> +# These are all the empty string if the compiler *isn't* X or
> +# earlier. Note that clang v5, v6 etc. also qualify as "have v4".
I had to read this three times and still cannot decide what it wants
ot say.
> +CC_HAVE_CLANG4 = $(filter clang4,$(COMPILER_FEATURES))
> +CC_HAVE_GCC4 = $(filter gcc4,$(COMPILER_FEATURES))
> +CC_HAVE_GCC5 = $(filter gcc5,$(COMPILER_FEATURES))
> +CC_HAVE_GCC6 = $(filter gcc6,$(COMPILER_FEATURES))
> +CC_HAVE_GCC10 = $(filter gcc10,$(COMPILER_FEATURES))
It is empty if the compiler isn't X. It is also empty if the
compiler isn't earlier than X? That would mean version (X+1) would
qualify, as it is not X, which is not what we want.
I think you meant "... empty string, unless the compiler is X or
later."
Also, I often see "Note that" to imply "despite what I just said",
but as far as I can tell CLANG4 is not all that special and follows
the same general rule. Perhaps "Note that" -> "For example," is
needed to clarify.
Having said all that, I find that the original
ifneq ($(filter x y, $(COMPILER_FEATURES)),)
idiom is readable enough, and
ifneq ($(CC_HAVE_X)$(CC_HAVE_Y),)
does not necessarily make it easier to spot X and Y that are being
checked with the conditional.
> ifeq ($(filter no-error,$(DEVOPTS)),)
> DEVELOPER_CFLAGS += -Werror
> SPARSE_FLAGS += -Wsparse-error
> @@ -9,9 +17,9 @@ endif
> DEVELOPER_CFLAGS += -Wall
> ifeq ($(filter no-pedantic,$(DEVOPTS)),)
> DEVELOPER_CFLAGS += -pedantic
> -ifneq ($(filter clang4 gcc5,$(COMPILER_FEATURES)),)
> +ifneq ($(CC_HAVE_CLANG4)$(CC_HAVE_GCC5),)
prev parent reply other threads:[~2021-09-28 21:30 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
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 [this message]
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