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PR ld/12253 DW_EH_PE_datarel

Jakub Jelinek jakub@redhat.com
Thu Nov 25 17:58:00 GMT 2010 
On Thu, Nov 25, 2010 at 05:35:01PM +0100, Rainer Orth wrote:
> Jakub Jelinek <jakub@redhat.com> writes:
> 
> > On Wed, Nov 24, 2010 at 10:57:25AM +1030, Alan Modra wrote:
> >> architecture dependent, it is also context sensitive.  When used in
> >> .eh_frame_hdr, DW_EH_PE_datarel means relative to the .eh_frame_hdr
> >> section.
> >
> > Yeah, I'm sorry for that, but it is documented that way and
> 
> Is there any written/formal documention for that, other than binutils
> and gcc (gcc/unwind-fde-dw2-glibc.c) sources?

The comment in elf-eh-frame.c in binutils is the written documentation:

/* Write out .eh_frame_hdr section.  This must be called after
   _bfd_elf_write_section_eh_frame has been called on all input
   .eh_frame sections.
   .eh_frame_hdr format:
   ubyte version                (currently 1)
   ubyte eh_frame_ptr_enc       (DW_EH_PE_* encoding of pointer to start of
                                 .eh_frame section)
   ubyte fde_count_enc          (DW_EH_PE_* encoding of total FDE count
                                 number (or DW_EH_PE_omit if there is no
                                 binary search table computed))
   ubyte table_enc              (DW_EH_PE_* encoding of binary search table,
                                 or DW_EH_PE_omit if not present.
                                 DW_EH_PE_datarel is using address of
                                 .eh_frame_hdr section start as base)
   [encoded] eh_frame_ptr       (pointer to start of .eh_frame section)
   optionally followed by:
   [encoded] fde_count          (total number of FDEs in .eh_frame section)
   fde_count x [encoded] initial_loc, fde
                                (array of encoded pairs containing
                                 FDE initial_location field and FDE address,
                                 sorted by increasing initial_loc).  */

	Jakub
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