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Re: Discard zero address range eh_frame FDEs
- From: Matthias Klose <doko at ubuntu dot com>
- To: Alan Modra <amodra at gmail dot com>
- Cc: binutils at sourceware dot org
- Date: Thu, 09 Oct 2014 09:23:23 +0200
- Subject: Re: Discard zero address range eh_frame FDEs
- Authentication-results: sourceware.org; auth=none
- References: <20141004132545 dot GB5112 at bubble dot grove dot modra dot org>
Am 04.10.2014 um 15:25 schrieb Alan Modra:
> Zero address range FDEs are useless because they can't match any
> address. In fact, worse than useless because the .eh_frame_hdr lookup
> table matching addresses to FDEs does not contain information about
> the FDE range. The table is sorted by address; Range is inferred by
> the address delta from one entry to the next. So if a zero address
> range FDE is followed by a normal non-zero range FDE for the same
> address, everything is good. The zero address range FDE will be seen
> as having zero range, and the normal FDE an address range up to the
> next FDE. However, the qsort could just as easily sort the FDEs in
> the other order, in which case the normal FDE would be seen to have a
> zero range.
this still leaves some link failures for more unusual packages, where ld -r is
used to create intermediate files.
Filed https://sourceware.org/bugzilla/show_bug.cgi?id=17467 and put together a
tarball with the object files for x86_64.
Matthias