From: Florian Weimer <fw@deneb.enyo.de>
To: Michael Matz <matz@suse.de>
Cc: Fangrui Song <maskray@google.com>,
GNU C Library <libc-alpha@sourceware.org>,
Binutils <binutils@sourceware.org>
Subject: Re: Suppress the fetch of an archive member via --defsym (glibc/elf/librtld.map.o)
Date: Sat, 11 Apr 2020 19:04:30 +0200 [thread overview]
Message-ID: <87a73i7y3l.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <alpine.LSU.2.21.2003161845540.30534@wotan.suse.de> (Michael Matz's message of "Mon, 16 Mar 2020 19:05:59 +0000 (UTC)")
* Michael Matz:
> On Mon, 16 Mar 2020, Fangrui Song via Binutils wrote:
>> I am concerned that the --defsym's order dependence with archive files is not
>> so obvious, given -u's behavior:
>>
>> # -u inserts an undefined which fetches b.a(b.o)
>> ld.bfd -u foo b.a # b.a(b.o) is fetched. free is present
>> # This can't be order dependent because b.a (not in a group) should have been
>> dropped when we saw -u
>> ld.bfd b.a -u foo # b.a(b.o) is fetched. free is present
>>
>> Some observations:
>>
>>
>> # GNU ld --defsym interacts with an archive
>> ld.bfd a.o b.a --defsym foo=0 # b.a(b.o) is fetched. free is present
>> ld.bfd --defsym foo=0 a.o b.a # b.a(b.o) is not fetched. free is absent
>
> I consider this the correct linker behaviour. In that sense I would
> consider the inconsistency with -u and -T to be the problems of those, not
> a problem of --defsym (but not necessarily problems we can fix anymore, as
> people might rely on that). (i.e. I think the second -u command above
> should result in an 'undefined foo' output/error, not in b.a(b.o) being
> fetched).
I agree, the ld.bfd behavior seems the most reasonable one to me.
next prev parent reply other threads:[~2020-04-11 17:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-16 4:58 Fangrui Song
2020-03-16 5:02 ` Fangrui Song
2020-03-16 11:27 ` H.J. Lu
2020-03-16 15:47 ` Fangrui Song
2020-03-16 16:01 ` H.J. Lu
2020-03-16 18:31 ` Fangrui Song
2020-03-16 19:05 ` Michael Matz
2020-03-21 16:39 ` Fangrui Song
2020-04-11 17:04 ` Florian Weimer [this message]
2020-04-11 18:16 ` Fangrui Song
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