linux-kernel - Re: [PATCH v2 1/2] kbuild: revive "Entering directory" for Make >= 4.4.1

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Message-ID: <CAK7LNAT5hSH5ov2AQOVsfzCSOTFnECMK1-t5AfvCpbAeWMa9ag@mail.gmail.com>
Date:   Sun, 25 Jun 2023 17:03:53 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     linux-kbuild@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nicolas Schier <nicolas@...sle.eu>,
        David Howells <dhowells@...hat.com>
Subject: Re: [PATCH v2 1/2] kbuild: revive "Entering directory" for Make >= 4.4.1

On Fri, Jun 16, 2023 at 11:57 PM Masahiro Yamada <masahiroy@...nel.org> wrote:
>
> With commit 9da0763bdd82 ("kbuild: Use relative path when building in
> a subdir of the source tree"), compiler messages in out-of-tree builds
> include relative paths, which are relative to the build directory, not
> the directory where make was started.
>
> To help IDEs/editors find the source files, Kbuild lets GNU Make print
> "Entering directory ..." when it changes the working directory. It has
> been working fine for a long time, but David reported it is broken with
> the latest GNU Make.
>
> The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537]
> Fix setting -w in makefiles"). Previously, setting --no-print-directory
> to MAKEFLAGS only affected child makes, but it is now interpreted in
> the current make as soon as it is set.
>
> [test code]
>
>   $ cat /tmp/Makefile
>   ifneq ($(SUBMAKE),1)
>   MAKEFLAGS += --no-print-directory
>   all: ; $(MAKE) SUBMAKE=1
>   else
>   all: ; :
>   endif
>
> [before 8f9e7722ff0f]
>
>   $ make -C /tmp
>   make: Entering directory '/tmp'
>   make SUBMAKE=1
>   :
>   make: Leaving directory '/tmp'
>
> [after 8f9e7722ff0f]
>
>   $ make -C /tmp
>   make SUBMAKE=1
>   :
>
> Previously, the effect of --no-print-directory was delayed until Kbuild
> started the directory descending, but it is no longer true with GNU Make
> 4.4.1.
>
> This commit adds one more recursion to cater to GNU Make >= 4.4.1.
>
> When Kbuild needs to change the working directory, __submake will be
> executed twice.
>
>   __submake without --no-print-directory  --> show "Entering directory ..."
>   __submake with    --no-print-directory  --> parse the rest of Makefile
>
> We end up with one more recursion than needed for GNU Make < 4.4.1, but
> I do not want to complicate the version check.
>
> Reported-by: David Howells <dhowells@...hat.com>
> Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/
> Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
> ---
>
> Changes in v2:
>   - Fix the code. V1 did not work.
>   - Remove the version check to simplify the code


This patch broke 'make rpm-pkg'  (and 'make snap-pkg' as well).

I will send v3.











-- 
Best Regards
Masahiro Yamada