From: John David Anglin <dave.anglin@bell.net>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: GNU C Library <libc-alpha@sourceware.org>,
Carlos O'Donell <carlos@systemhalted.org>
Subject: Re: [committed] Return to caller when _dl_fixup fails on hppa
Date: Sun, 16 Jul 2017 22:02:00 -0000 [thread overview]
Message-ID: <859EA4CC-A29C-4E31-97D5-57A9598DB5C6@bell.net> (raw)
In-Reply-To: <87mv84gjbf.fsf@linux-m68k.org>
On 2017-07-16, at 5:31 PM, Andreas Schwab wrote:
>> That's assumed. However, it doesn't work on hppa. The caller has access to a non NULL pointer
>> to a function descriptor.
>
> It works well on ia64 and ppc64, why not on hppa?
32-bit hppa doesn't have official procedure descriptors (OPDs). Carlos at one time indicated that
he wanted to rework binutils elf32-hppa.c to use OPDs but it never happened. As a result, undefined
weak symbols are poorly supported.
It was a bad design and HP recognized it when they created the 64-bit hppa and ia64 runtimes. The
32-bit hpux linker doesn't support undefined weak symbols at all. We worked around it with one-only
support in gcc.
Anyway, one compare instruction checking the return of _dl_fixup doesn't affect performance much.
It could be removed if the problems with undefined weak functions are resolved.
Dave
--
John David Anglin dave.anglin@bell.net
next prev parent reply other threads:[~2017-07-16 22:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-16 17:50 John David Anglin
2017-07-16 18:53 ` Andreas Schwab
2017-07-16 19:46 ` John David Anglin
2017-07-16 21:31 ` Andreas Schwab
2017-07-16 22:02 ` John David Anglin [this message]
2017-07-17 7:10 ` Andreas Schwab
2017-07-17 11:11 ` Carlos O'Donell
2017-07-17 11:52 ` John David Anglin
2017-07-23 23:58 ` John David Anglin
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