From: David Miller <davem@davemloft.net>
To: thomas@codesourcery.com
Cc: binutils@sourceware.org, aoliva@redhat.com, kkojima@rr.iij4u.or.jp
Subject: Re: [SH] TLS IE -> LE optimization issue
Date: Fri, 13 Apr 2012 15:55:00 -0000 [thread overview]
Message-ID: <20120413.115316.1972942705768732499.davem@davemloft.net> (raw)
In-Reply-To: <87obqvpr9l.fsf@schwinge.name>
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Fri, 13 Apr 2012 17:48:06 +0200
> (This is also where the (dummy) SO comes into play: otherwise »dyn ==
> NULL«.) Back in sh_elf_size_dynamic_sections, »srelgot->size != 0«
> (»sizeof (Elf32_External_Rela) == 12«), thus memory for this section will
> be allocated (using bfd_zalloc). Later on, in sh_elf_relocate_section,
> the linker recognizes that TLS IE can here be optimized into TLS LE, and
> does so; the relocation slot is now not needed anymore (so
> srelgot->reloc_count is not incremented), but it is not reclaimed/the
> size reservation remains (and due to using zalloc, it's a R_SH_NONE), and
> thus the assertion is triggered.
>
> Expectedly, weakening the assertion into using <= instead of == makes the
> problem go away, but the empty slot in .rela.dyn remains (12 bytes
> wasted).
>
> Or, instead, should the srelgot->size reservations be un-done as the TLS
> optimizations are done (there may be other such cases, I didn't check)?
> Can this actually be done at this stage?
>
> Or, should there be another cleanup pass after the TLS optimizations have
> been done? Or, should one of the existing passes in fact be catching
> this case, too?
Sparc, which makes similar transformations, lacks the assertion you
mention altogether.
In fact SH is one of the few backends I see making this size check.
next prev parent reply other threads:[~2012-04-13 15:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-13 15:53 Thomas Schwinge
2012-04-13 15:55 ` David Miller [this message]
2012-04-14 0:27 ` Kaz Kojima
2012-04-15 22:18 ` Alan Modra
2012-04-16 11:47 ` Kaz Kojima
2012-04-17 12:36 ` Thomas Schwinge
2012-04-17 14:48 ` Kaz Kojima
2012-04-17 22:13 ` Kaz Kojima
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