Re: [linux@arm.linux.org.uk: Re: [CRITICAL PATCH] 2.6: fix silentbuild error]

[Dan Kegel <dank at kegel dot com>]

Lennert Buytenhek wrote:>
> Dunno if you saw this..

Nope.  I'm not reading any mailing lists these days, I'm on
a crosstool vacation...

> there appears to be a problem in many binutils
> versions for ARM where GNU as happily accepts an undefined symbol being
> used as an immediate w/o corresponding reloc, which silently causes the
> resulting code to use '0' instead of the intended value.
>
> http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-July/023128.html
> http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=1950/1
>
> It might be appropriate to include a patch along the lines of what was
> posted below into crosstool.

Thanks, sounds like I should add this!
- Dan

>   gas/ChangeLog
>   2004-07-01  Nick Clifton  <nickc@redhat.com>
>
>         * config/tc-arm.c (md_apply_fix3:BFD_RELOC_ARM_IMMEDIATE): Do not
>         allow values which have come from undefined symbols.
>         Always consider this fixup to have been processed as a reloc
>         cannot be generated for it.
>
>
> Index: gas/config/tc-arm.c
> ===================================================================
> RCS file: /work/repositories/sourceware/src/gas/config/tc-arm.c,v
> retrieving revision 1.140.2.1
> diff -c -3 -p -r1.140.2.1 tc-arm.c
> *** gas/config/tc-arm.c	13 Jun 2003 16:34:31 -0000	1.140.2.1
> --- gas/config/tc-arm.c	1 Jul 2004 17:22:43 -0000
> *************** md_apply_fix3 (fixP, valP, seg)
> *** 10693,10698 ****
> --- 10693,10712 ----
>     switch (fixP->fx_r_type)
>       {
>       case BFD_RELOC_ARM_IMMEDIATE:
> +       /* We claim that this fixup has been processed here,
> + 	 even if in fact we generate an error because we do
> + 	 not have a reloc for it, so tc_gen_reloc will reject it.  */
> +       fixP->fx_done = 1;
> + 
> +       if (fixP->fx_addsy
> + 	  && ! S_IS_DEFINED (fixP->fx_addsy))
> + 	{
> + 	  as_bad_where (fixP->fx_file, fixP->fx_line,
> + 			_("undefined symbol %s used as an immediate value"),
> + 			S_GET_NAME (fixP->fx_addsy));
> + 	  break;
> + 	}
> + 
>         newimm = validate_immediate (value);
>         temp = md_chars_to_number (buf, INSN_SIZE);
>   
> *************** md_apply_fix3 (fixP, valP, seg)
> *** 10709,10715 ****
>   
>         newimm |= (temp & 0xfffff000);
>         md_number_to_chars (buf, (valueT) newimm, INSN_SIZE);
> -       fixP->fx_done = 1;
>         break;
>   
>       case BFD_RELOC_ARM_ADRL_IMMEDIATE:
> --- 10723,10728 ----
>
>
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--
My technical stuff: http://kegel.com
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