Re: [PATCH] Fix building several uclinux target

[Nathan Froyd <froydnj@codesourcery.com>]

On Thu, Jul 15, 2010 at 08:00:24PM +0400, Maxim Kuvyrkov wrote:
>> The following patch should fix the build of moxie-uclinux toolchain. The
>> problem was that the piece of config.gcc defining supported linux C
>> libraries isn't executed for most uclinux targets, moxie included.
>> Still, many uclinux targets includes linux.h and linux.opt, which
>> yielded an error.

This patch breaks building a cross to powerpc-eabispe (possibly other
powerpc SysV4-ish non-Linux targets).  Reverting this
bit:

> Index: gcc/config.gcc
> ===================================================================
> --- gcc/config.gcc	(revision 162059)
> +++ gcc/config.gcc	(working copy)
> @@ -405,6 +405,9 @@ case ${target} in
>  	;;
>  esac
>  
> +# Common C libraries.  There are mere constants.
> +tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
> +
>  # Common parts for widely ported systems.
>  case ${target} in
>  *-*-darwin*)
> @@ -508,8 +511,6 @@ case ${target} in
>      *-*-gnu*)
>        tmake_file="$tmake_file t-gnu";;
>    esac
> -  # Common C libraries.
> -  tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
>    # glibc / uclibc / bionic switch.
>    # uclibc and bionic aren't usable for GNU/Hurd and neither for GNU/k*BSD.
>    case $target in

fixes things.

I think this is because of this hunk in config/rs6000/sysv4.h:

#define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
#define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
#if DEFAULT_LIBC == LIBC_UCLIBC
#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:" G ";:" U "}"
#elif DEFAULT_LIBC == LIBC_GLIBC
#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:" U ";:" G "}"
#else
#error "Unsupported DEFAULT_LIBC"
#endif
#define LINUX_DYNAMIC_LINKER \
  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)

After your patch, LIBC_{UCLIBC,GLIBC} are defined unconditionally;
DEFAULT_LIBC is not defined, so we now fall through to the #error case.

Perhaps the toplevel code should now be:

case $target in
*-*-*linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu)
  # Common C libraries.
  tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
  ;;
esac

to catch the uclinux targets as well?

-Nathan