Re: [PATCH, FT32] initial support (2nd attempt)

[Alan Modra <amodra at gmail dot com>]

On Mon, Jan 05, 2015 at 08:08:17PM +0000, James Bowman wrote:
> +  HOWTO (R_FT32_32,		/* type */
> +	 0,			/* rightshift */
> +	 2,			/* size (0 = byte, 1 = short, 2 = long) */
> +	 32,			/* bitsize */
> +	 FALSE,			/* pc_relative */
> +	 0,			/* bitpos */
> +	 complain_overflow_bitfield, /* complain_on_overflow */
> +	 bfd_elf_generic_reloc,	/* special_function */
> +	 "R_FT32_32",		/* name */
> +	 FALSE,			/* partial_inplace */
> +	 0x00000000,		/* src_mask */
> +	 0x000fffff,		/* dst_mask */
> +	 FALSE),		/* pcrel_offset */

This problem still remains.  You have a 20-bit dst_mask, where I'd
expect to see 0xffffffff for a 32-bit reloc.

> +  /* This is the standard place for KLUDGEs to work around bugs in
> +     bfd_install_relocation (first such note in the documentation
> +     appears with binutils-2.8).
> +
> +     That function bfd_install_relocation does the wrong thing with
> +     putting stuff into the addend of a reloc (it should stay out) for a
> +     weak symbol.  The really bad thing is that it adds the
> +     "segment-relative offset" of the symbol into the reloc.  In this
> +     case, the reloc should instead be relative to the symbol with no
> +     other offset than the assembly code shows; and since the symbol is
> +     weak, any local definition should be ignored until link time (or
> +     thereafter).
> +     To wit:  weaksym+42  should be weaksym+42 in the reloc,
> +     not weaksym+(offset_from_segment_of_local_weaksym_definition)
> +
> +     To "work around" this, we subtract the segment-relative offset of
> +     "known" weak symbols.  This evens out the extra offset.
> +
> +     That happens for a.out but not for ELF, since for ELF,
> +     bfd_install_relocation uses the "special function" field of the
> +     howto, and does not execute the code that needs to be undone.  */
> +
> +  if (OUTPUT_FLAVOR == bfd_target_aout_flavour
> +      && fixP->fx_addsy && S_IS_WEAK (fixP->fx_addsy)
> +      && ! bfd_is_und_section (S_GET_SEGMENT (fixP->fx_addsy)))
> +    {
> +      relP->addend -= S_GET_VALUE (fixP->fx_addsy);
> +    }

This too.  If you don't plan to support AOUT in the near future,
please remove the above.

-- 
Alan Modra
Australia Development Lab, IBM