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From: Jim Ingham <jingham@apple.com>
Subject: Re: [RFC] The never ending 32-bit vs. 64-bit blues
Date: Mon, 07 Nov 2005 22:50:00 -0000
To: Mark Kettenis <mark.kettenis@xs4all.nl>
X-SW-Source: 2005-11/txt/msg00181.txt.bz2

Just as a point of information, Apple's PPC gdb (built 32 bit) can  
debug both 32 and 64 bit PPC apps.  We have a 32 bit native gdb with  
a 32 bit and a 64 bit gdbarch.  Seems to work okay so far.

Jim

On Nov 7, 2005, at 2:45 PM, Mark Kettenis wrote:

> In the past we have had a lot of bug reports from people trying to
> debug 64-bit programs with a native 32-bit gdb.  As far as I know we
> don't support any native configuration that allows this.  I've never
> quite managed to come up with a satisfactory solution to deal with
> this.  Here's an attempt to deal with it by making configure complain.
>
> Any opinions about this?
>
> Mark
>
>
> Index: configure.ac
> ===================================================================
> RCS file: /cvs/src/src/gdb/configure.ac,v
> retrieving revision 1.24
> diff -u -p -r1.24 configure.ac
> --- configure.ac    25 Jul 2005 15:08:40 -0000    1.24
> +++ configure.ac    7 Nov 2005 22:34:19 -0000
> @@ -34,6 +34,19 @@ AM_PROG_CC_STDC
>  AC_CONFIG_AUX_DIR(`cd $srcdir;pwd`/..)
>  AC_CANONICAL_SYSTEM
>
> +# Sanity check; refuse to build a native GDB for a 64-bit target with
> +# a 32-bit compiler.
> +AC_CHECK_SIZEOF(void *)
> +if test "${target}" = "${host}"; then
> +  case "$host_cpu" in
> +  hppa64|mips64*|powerpc64|sparc64|x86_64)
> +    if test $ac_cv_sizeof_void_p != 8; then
> +      AC_MSG_ERROR(
> +[building native target ${host} with a 32-bit compiler is not  
> supported])
> +    fi
> +  esac
> +fi
> +
>  dnl List of object files and targets accumulated by configure.
>
>  CONFIG_OBS=
>