struct siginfo vs. siginfo_t (was: GNU C Library master sources branch, master, updated. glibc-2.15-229-g4efeffc)

[Thomas Schwinge <thomas at codesourcery dot com>]

Hi!

On 26 Feb 2012 18:17:52 -0000, drepper@sourceware.org wrote:
> http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=4efeffc1d583597e4f52985b9747269e47b754e2
> 
> commit 4efeffc1d583597e4f52985b9747269e47b754e2
> Author: Ulrich Drepper <drepper@gmail.com>
> Date:   Sun Feb 26 13:17:27 2012 -0500
> 
>     Fix up POSIX testing in conformtest

> [...]
> +	* sysdeps/unix/sysv/linux/bits/siginfo.h: Don't name siginfo_t
> +	struct.  [...]
> [...]

> diff --git a/sysdeps/unix/sysv/linux/bits/siginfo.h b/sysdeps/unix/sysv/linux/bits/siginfo.h
> index ecef39d..0635e2f 100644
> --- a/sysdeps/unix/sysv/linux/bits/siginfo.h
> +++ b/sysdeps/unix/sysv/linux/bits/siginfo.h
> [...]
> @@ -47,7 +47,7 @@ typedef union sigval
>  #  define __SI_PAD_SIZE     ((__SI_MAX_SIZE / sizeof (int)) - 3)
>  # endif
>  
> -typedef struct siginfo
> +typedef struct
>    {
>      int si_signo;		/* Signal number.  */
>      int si_errno;		/* If non-zero, an errno value associated with
> [...]

This change breaks GCC:

    In file included from /scratch/tschwing/FM_sh-linux-gnu-mk2/src/gcc-mainline/libgcc/unwind-dw2.c:377:0:
    ./md-unwind-support.h: In function 'sh_fallback_frame_state':
    ./md-unwind-support.h:182:17: error: field 'info' has incomplete type

In my case, this is really libgcc/config/sh/linux-unwind.h:

    [...]
       181	      struct rt_sigframe {
       182		struct siginfo info;
       183		struct ucontext uc;
       184	      } *rt_ = context->cfa;
    [...]

There are more such cases:

    boehm-gc/os_dep.c:#   define SIGINFO_T struct siginfo
    libgcc/config/alpha/linux-unwind.h:   struct siginfo info;
    libgcc/config/bfin/linux-unwind.h:    struct siginfo *pinfo;
    libgcc/config/bfin/linux-unwind.h:    struct siginfo info;
    libgcc/config/i386/linux-unwind.h:    struct siginfo *pinfo;
    libgcc/config/i386/linux-unwind.h:    struct siginfo info;
    libgcc/config/ia64/linux-unwind.h:    struct siginfo *info;
    libgcc/config/ia64/linux-unwind.h:    struct siginfo *info;
    libgcc/config/mips/linux-unwind.h:    struct siginfo info;
    libgcc/config/pa/linux-unwind.h:    struct siginfo info;
    libgcc/config/sh/linux-unwind.h:      struct siginfo *pinfo;
    libgcc/config/sh/linux-unwind.h:      struct siginfo info;
    libgcc/config/sh/linux-unwind.h:      struct siginfo info;
    libgcc/config/tilepro/linux-unwind.h:    struct siginfo info;
    libgcc/config/xtensa/linux-unwind.h:    struct siginfo info;

(Is there really nobody doing nightly testing of GCC against glibc master
branch on x86, which would have shown this earlier?)

Replacing struct siginfo with siginfo_t in sh/linux-unwind.h makes the
build pass.  Is this the desired approach; shall we apply this for all
cases listed above (and submit to Boehm GC upstream)?  I wonder -- if GCC
breaks, how much software out in the wild is going to break once this
glibc change ripples through?


GrÃÃe,
 Thomas

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