Problems converting elf32-sh to coff-sh

Problems converting elf32-sh to coff-sh

[François Costin]

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I need for some reason to convert simple elf object files into coff files.

My compiler produces some R_SH_DIR32 relocations which are not supported by
the binutils for the conversion.  I know you can't do it in the general
case, but I've managed somehow to remap the R_SH_DIR32 as a R_SH_IMM32
reloc.  This part seems to work fine.

Only one exception... when an object file contains a reloc to a function
inside that same object file, the converter adds a weird negative offset to
the symbol name when I ask for an objdump -x.

I did find where the offset comes from there's a line in the coff-sh.c file
inside the CALC_ADDEND macro which goes like this:

cache_ptr->addend = -(ptr->section->vma + ptr->value);

I did try to simply change this to:

cache_ptr->addend = 0;

Now, after doing an objcopy -O coff-sh, when I do an objdump -x with the new
code, I do not see the offset.  But when I do the objdump with an older
version of the code, it does see it.  And it fact it stays there.

I'd just like to know where in the code I can once and for all delete that
offset.  It is only for that specific application and I know that if I can
delete the offset, I'll have no problems anymore converting my object files.

I hope I made myself clear.  I can give more details if needed!


François Costin

Electrical Engineering
Technologies Lyre Inc.

Re: Problems converting elf32-sh to coff-sh

[Ian Lance Taylor]

   From: =?iso-8859-1?Q?Fran=E7ois_Costin?= <costin00@gel.ulaval.ca>
   Date: Fri, 10 Sep 1999 17:44:19 -0400

   I need for some reason to convert simple elf object files into coff files.

   My compiler produces some R_SH_DIR32 relocations which are not supported by
   the binutils for the conversion.  I know you can't do it in the general
   case, but I've managed somehow to remap the R_SH_DIR32 as a R_SH_IMM32
   reloc.  This part seems to work fine.

   Only one exception... when an object file contains a reloc to a function
   inside that same object file, the converter adds a weird negative offset to
   the symbol name when I ask for an objdump -x.

   I did find where the offset comes from there's a line in the coff-sh.c file
   inside the CALC_ADDEND macro which goes like this:

   cache_ptr->addend = -(ptr->section->vma + ptr->value);

   I did try to simply change this to:

   cache_ptr->addend = 0;

   Now, after doing an objcopy -O coff-sh, when I do an objdump -x with the new
   code, I do not see the offset.  But when I do the objdump with an older
   version of the code, it does see it.  And it fact it stays there.

   I'd just like to know where in the code I can once and for all delete that
   offset.  It is only for that specific application and I know that if I can
   delete the offset, I'll have no problems anymore converting my object files.

You've already figured out how to delete that offset: change the
CALC_ADDEND macro.

I don't understand what else you are asking for.  For coff-sh, the
addend computed by CALC_ADDEND and reported by objdump -x doesn't
reflect any value that actually appears in the object file.  It is a
value computed solely to make the link work correctly.

Try generating a COFF file directly using the assembler, and see what
you get.  You want to get the same results after the conversion from
ELF.

Ian