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From: Ramsay Jones <ramsay@ramsayjones.plus.com>
To: Danh Doan <congdanhqx@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH v2 2/4] compat/regex: include alloca.h before undef it
Date: Sun, 26 Apr 2020 20:38:26 +0100	[thread overview]
Message-ID: <1a0c2b25-e283-9936-1fa2-ce51df1404dc@ramsayjones.plus.com> (raw)
In-Reply-To: <e9163e0d-2572-e7e0-6aa3-09ce04750b22@ramsayjones.plus.com>



On 26/04/2020 17:17, Ramsay Jones wrote:
[snip]

> Hmm, whatever patch you decide to send (even the original one) I think
> you need to add an explanation of the problem to the commit message,
> including why the patch provides a solution. (You don't have to type
> a novel - see commit bd8f005583 :-P ).
> 
> I haven't thought about this too much, but some options:
> 
>   - iff the musl library sets some kind of identifying pp variable
>     (_MUSL_LIBC_ or somesuch - I haven't looked), then you could
>     make the '#include <alloca.h>' conditional on that variable.
>     This has the benefit of making it obvious to people reading the
>     code that this is specific to musl-libc.
> 
>   - you could simply remove that '#ifdef GAWK' block completely (Lines
>     64->67). We set GAWK and NO_MBSUPPORT  unconditionally in the Makefile
>     so that it compiles (see commit a997bf423d), but these particular
>     lines simply reflect the gawk projects dislike of alloca (along with
>     the desire to catch any attempts to add new calls which are not protected
>     by HAVE_ALLOCA). Given that we are very unlikely to add new calls ...
> 
>   - change the conditional on this block to (totally untested, just typing
>     into my email client) '#if defined(GAWK) && defined(HAVE_ALLOCA)'.
>     This should work, but it does disable the 'catch any attempts to add
>     new _unintentional_ calls' aspect of that block; so you may as well
>     remove it ...
> 
> Just some 'off the top of my head ideas', ... ;-)

Another option I thought about, but didn't mention above, is given by
the patch below. I didn't mention it because it has the potential to
cause problems on non musl-libc systems (and I was feeling too lazy at
the time to go and test ...). Again, see commit bd8f005583.

So, I have now tested this patch on (glibc) linux and it seems to work
just fine; compile, sparse, test-suite passed. It also compiles clean
(and sparse clean) on cygwin (new-lib) - I didn't run the test-suite
on cygwin, since it takes about 3.5 to 4 hours to run.

I don't have any other systems to test this on, so I can't say that it
won't cause problems somewhere. In practice, I think the chances of that
are rather low, but don't quote me on that! :-P

ATB,
Ramsay Jones

-- >8 --
Subject: [PATCH] regex: fix up musl-libc builds

---
 compat/regex/regex.c          | 1 +
 compat/regex/regex_internal.h | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/regex/regex.c b/compat/regex/regex.c
index f3e03a9eab..e6f4a5d177 100644
--- a/compat/regex/regex.c
+++ b/compat/regex/regex.c
@@ -60,6 +60,7 @@
    #undefs RE_DUP_MAX and sets it to the right value.  */
 #include <limits.h>
 #include <stdint.h>
+#include <stdlib.h>
 
 #ifdef GAWK
 #undef alloca
diff --git a/compat/regex/regex_internal.h b/compat/regex/regex_internal.h
index 3ee8aae59d..0bad8b841e 100644
--- a/compat/regex/regex_internal.h
+++ b/compat/regex/regex_internal.h
@@ -23,7 +23,6 @@
 #include <assert.h>
 #include <ctype.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 #if defined HAVE_LANGINFO_H || defined HAVE_LANGINFO_CODESET || defined _LIBC
-- 
2.26.2


  reply	other threads:[~2020-04-26 19:38 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-23 13:47 [PATCH 0/4] fix make sparse warning Đoàn Trần Công Danh
2020-04-23 13:47 ` [PATCH 1/4] C: s/0/NULL/ for pointer type Đoàn Trần Công Danh
2020-04-24  0:39   ` Ramsay Jones
2020-04-24  0:54     ` Junio C Hamano
2020-04-24  1:09       ` Danh Doan
2020-04-24  1:54         ` Junio C Hamano
2020-05-14 21:37       ` Luc Van Oostenryck
2020-04-23 13:47 ` [PATCH 2/4] compat/regex: silence `make sparse` warning Đoàn Trần Công Danh
2020-04-24  0:51   ` Ramsay Jones
2020-04-24  1:04     ` Danh Doan
2020-04-23 13:47 ` [PATCH 3/4] graph.c: limit linkage of internal variable Đoàn Trần Công Danh
2020-04-24  0:52   ` Ramsay Jones
2020-04-23 13:47 ` [PATCH 4/4] progress.c: silence cgcc suggestion about internal linkage Đoàn Trần Công Danh
2020-04-24  0:58   ` Ramsay Jones
2020-04-24  5:54     ` Jeff King
2020-04-23 13:47 ` [PATCH 5/4] fmt-merge-msg.c: fix `make sparse` on next Đoàn Trần Công Danh
2020-04-23 23:10 ` [PATCH 0/4] fix make sparse warning Ramsay Jones
2020-04-23 23:58   ` Danh Doan
2020-04-24 16:38     ` Ramsay Jones
2020-04-24 15:12 ` [PATCH v2 0/4] Fix Sparse Warning Đoàn Trần Công Danh
2020-04-24 15:12   ` [PATCH v2 1/4] test-parse-pathspec-file.c: s/0/NULL/ for pointer type Đoàn Trần Công Danh
2020-04-24 15:12   ` [PATCH v2 2/4] compat/regex: include alloca.h before undef it Đoàn Trần Công Danh
2020-04-24 16:56     ` Ramsay Jones
2020-04-24 17:09       ` Danh Doan
2020-04-24 18:29         ` Ramsay Jones
2020-04-24 22:34           ` Danh Doan
2020-04-25 20:28             ` Ramsay Jones
2020-04-26  0:54               ` Danh Doan
2020-04-26  1:10                 ` Danh Doan
2020-04-26 16:17                 ` Ramsay Jones
2020-04-26 19:38                   ` Ramsay Jones [this message]
2020-04-26 22:37                     ` Junio C Hamano
2020-04-27  1:08                   ` Danh Doan
2020-04-27 16:28                     ` Ramsay Jones
2020-04-27 16:46                       ` Danh Doan
2020-04-27 17:21                         ` Ramsay Jones
2020-04-24 15:12   ` [PATCH v2 3/4] graph.c: limit linkage of internal variable Đoàn Trần Công Danh
2020-04-24 15:12   ` [PATCH v2 4/4] progress.c: silence cgcc suggestion about internal linkage Đoàn Trần Công Danh
2020-04-24 16:40   ` [PATCH v2 0/4] Fix Sparse Warning Ramsay Jones
2020-04-25 13:13 ` [PATCH 0/4] fix make sparse warning Johannes Schindelin
2020-04-26  3:32   ` Danh Doan
2020-04-26 16:24     ` Ramsay Jones
2020-05-01 20:02       ` Johannes Schindelin
2020-04-27 14:22 ` [PATCH v3 0/4] Partial fix `make sparse` Đoàn Trần Công Danh
2020-04-27 14:22   ` [PATCH v3 1/4] test-parse-pathspec-file.c: s/0/NULL/ for pointer type Đoàn Trần Công Danh
2020-04-27 14:22   ` [PATCH v3 2/4] compat/regex: move stdlib.h up in inclusion chain Đoàn Trần Công Danh
2020-04-27 16:41     ` Ramsay Jones
2020-04-27 14:22   ` [PATCH v3 3/4] graph.c: limit linkage of internal variable Đoàn Trần Công Danh
2020-04-27 14:22   ` [PATCH v3 4/4] progress.c: silence cgcc suggestion about internal linkage Đoàn Trần Công Danh
2020-05-01 20:09     ` Johannes Schindelin
2020-04-27 16:35   ` [PATCH v3 0/4] Partial fix `make sparse` Ramsay Jones

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