Re: elfxx-ia64.c question

[David Mosberger <davidm at napali dot hpl dot hp dot com>]

>>>>> On Fri, 24 Jan 2003 14:46:45 -0800, Richard Henderson <rth@redhat.com> said:

  >> Specifically, with @secrel() an exception-entry might look like
  >> this:
  >>
  >> .section "__ex_table", "a"
  >>
  >> .text [1:] INSTRUCTION_THAT MIGHT_FAULT .xdata4 "__ex_table",
  >> @secrel(1b), @secrel(1f) [1:] CONTINUATION_POINT
  >>
  >> The Linux kernel linker script normally places the __ex_table
  >> section after the .text section, such that the @secrel() entries
  >> are negative and the above "bug" kicks in and silently puts all
  >> zeroes in the exception table.  Not very useful.  I was able to
  >> fix it by moving __ex_table in front of .text, but that's not a
  >> very clean solution.
  >>
  >> It sounds to me like the linker doesn't expect @secrel() to go
  >> across sections, but from my reading of the ps-ABI this is legal.

  Richard> I don't think secrel really does what you want here.

I still would like to understand why BFD doesn't allow @secrel() with
negative offsets.  If there is a good reason to disallow this, the
psABI should be updated to reflect this constraint.  And if there
isn't a good reason, we should fix BFD.

Alan mentioned something about weak references, but I didn't fully
understand the exact circumstances he was referring to.  Could someone
provide a specific example (or reason) or where things fail if
@secrel() is allowed to produce negative values?

Thanks,

	--david