From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Masahiro Yamada <yamada.masahiro@socionext.com>,
linux-kbuild@vger.kernel.org
Cc: Sam Ravnborg <sam@ravnborg.org>,
Nicolas Pitre <nicolas.pitre@linaro.org>,
Michal Marek <michal.lkml@markovi.net>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/8] kbuild: change if_changed_rule to accept multi-line recipe
Date: Thu, 15 Nov 2018 10:12:18 +0100 [thread overview]
Message-ID: <6ee62b52-5d6d-c540-5f01-f522b6986c4d@rasmusvillemoes.dk> (raw)
In-Reply-To: <1542270435-11181-6-git-send-email-yamada.masahiro@socionext.com>
On 15/11/2018 09.27, Masahiro Yamada wrote:
> GNU Make supports 'define' ... 'endef' directive, which can describe
> a recipe that consists of multiple lines.
>
> endef
>
> This does not actually exploit the benefits of 'define' ... 'endef'
> form. All shell commands must be concatenated with '; \' so that it
> looks like a single command from the Makefile point of view. '@' can
> only appear before the first action.
>
> The root cause of this misfortune is the '@set -e;' in if_changed_rule.
> It is easily solvable by moving '@set -e' to the 'cmd' macro.
>
> The combo of $(call echo-cmd,*) $(cmd_*) in rule_cc_o_c and rule_as_o_S
> were replaced with $(call cmd,*). The tailing back-slashes went away.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
>
> define rule_cc_o_c
> - $(call echo-cmd,checksrc) $(cmd_checksrc) \
> - $(call cmd_and_fixdep,cc_o_c) \
> - $(cmd_gen_ksymdeps) \
> - $(cmd_checkdoc) \
> - $(call echo-cmd,objtool) $(cmd_objtool) \
> - $(cmd_modversions_c) \
> - $(call echo-cmd,record_mcount) $(cmd_record_mcount)
> + $(call cmd,checksrc)
> + @$(call cmd_and_fixdep,cc_o_c)
> + $(call cmd,gen_ksymdeps)
> + $(call cmd,checkdoc)
> + $(call cmd,objtool)
> + $(call cmd,modversions_c)
> + $(call cmd,record_mcount)
> endef
Does this mean that Make now spawns a new shell for each of these
commands, and if so, what's the performance impact? Or am I just
misreading things? If this does change the semantics (one shell instance
versus many), I think that's worth mentioning explicitly in the
changelog, regardless of whether there's no measuarable performance impact.
Rasmus
next prev parent reply other threads:[~2018-11-15 9:12 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-15 8:27 [PATCH 0/8] kbuild: clean-up modversion, TRIM_UNUSED_KSYMS, if_changed_rule, etc Masahiro Yamada
2018-11-15 8:27 ` [PATCH 1/8] kbuild: remove redundant 'set -e' from filechk_* defines Masahiro Yamada
2018-11-15 8:27 ` [PATCH 2/8] kbuild: remove redundant 'set -e' from sub_cmd_record_mcount Masahiro Yamada
2018-11-15 8:27 ` [PATCH 3/8] kbuild: refactor modversions build rules Masahiro Yamada
2018-11-16 20:01 ` Sam Ravnborg
2018-11-18 5:00 ` Masahiro Yamada
2018-11-15 8:27 ` [PATCH 4/8] kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS Masahiro Yamada
2018-11-16 5:13 ` Nicolas Pitre
2018-11-16 7:13 ` Masahiro Yamada
2018-11-16 17:49 ` Nicolas Pitre
2018-11-20 1:13 ` Masahiro Yamada
2018-11-15 8:27 ` [PATCH 5/8] kbuild: change if_changed_rule to accept multi-line recipe Masahiro Yamada
2018-11-15 9:12 ` Rasmus Villemoes [this message]
2018-11-16 1:37 ` Masahiro Yamada
2018-11-15 8:27 ` [PATCH 6/8] kbuild: remove trailing semicolon from cmd_* passed to if_changed_rule Masahiro Yamada
2018-11-15 8:27 ` [PATCH 7/8] kbuild: refactor if_changed and if_changed_dep Masahiro Yamada
2018-11-15 8:27 ` [PATCH 8/8] kbuild: remove redundant 'set -e' from cmd_* defines Masahiro Yamada
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6ee62b52-5d6d-c540-5f01-f522b6986c4d@rasmusvillemoes.dk \
--to=linux@rasmusvillemoes.dk \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=michal.lkml@markovi.net \
--cc=nicolas.pitre@linaro.org \
--cc=sam@ravnborg.org \
--cc=yamada.masahiro@socionext.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).