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Re: gnulib does not always detect need for iconv() hack on musl
From: |
Bruno Haible |
Subject: |
Re: gnulib does not always detect need for iconv() hack on musl |
Date: |
Sun, 17 Oct 2021 19:18:51 +0200 |
Hello Sergei,
Sergei Trofimovich wrote:
> The following fails bison-3.8.2 tests:
> $ ./configure && make && make check
> The following succeeds:
> $ ./configure --host=x86_64-unknown-linux-musl && make && make check
>
> The failure happens due to unexpected '*' output in report logs instead
> of '%empty' on 'ASCII' locales.
>
> These unexpected '*' pop back again because gnulib relies on '--host='
> parameter for './configure' to detect musl target (for lack of better
> signal?):
>
> https://git.savannah.gnu.org/cgit/gnulib.git/tree/m4/musl.m4#n16
>
> case "$host_os" in
> *-musl*) AC_DEFINE([MUSL_LIBC], [1], [Define to 1 on musl libc.]) ;;
>
> https://git.savannah.gnu.org/cgit/gnulib.git/tree/lib/unicodeio.c#n151
>
> /* FreeBSD iconv(), NetBSD iconv(), and Solaris 11 iconv() insert
> a '?' if they cannot convert. */
> # if !defined _LIBICONV_VERSION
> || (res > 0 && outptr - outbuf == 1 && *outbuf == '?')
> # endif
> /* musl libc iconv() inserts a '*' if it cannot convert. */
> # if !defined _LIBICONV_VERSION && MUSL_LIBC
> || (res > 0 && outptr - outbuf == 1 && *outbuf == '*')
> # endif
> )
> return failure (code, NULL, callback_arg);
>
> What do you think of enabling the workaround regardless of MUSL_LIBC
> define?
The MUSL_LIBC symbol is supposed to be set on musl platforms; this is
what musl.m4 is for. The difference between your two invocations is that
in the first case, it used a $host triple inferred by config.guess,
while in the second case, it used the $host that you specified on the
command line.
When I try your two commands (just the configure step), the first one
prints
checking for host system type... x86_64-pc-linux-musl
while the second one prints
checking for host system type... x86_64-unknown-linux-musl
The next steps of the investigation are: In the first case,
- What did the "checking for host system type..." line look like?
- Which of the environment variables CC_FOR_BUILD, HOST_CC, CC,
CONFIG_SITE did you have defined, and to which values?
> Or perhaps gnulib should perform runtime testing to detect the need for
> a hack? Here is how musl mangles symbols:
>
> https://git.musl-libc.org/cgit/musl/tree/src/locale/iconv.c#n545
>
> case US_ASCII:
> if (c > 0x7f) subst: x++, c='*';
>
> Below implements unconditional workaround.
Thanks for the suggestion. But we try to limit the performance implications
of hacks/workarounds needed for one platform (here: musl) on other platforms
(especially glibc platforms).
Bruno