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* [Bug libc/11394] New: locale-archive differs between x86_64-linux and i686-linux due to unintentional hash difference
@ 2010-03-17 6:30 cgd at google dot com
2010-03-17 6:36 ` [Bug libc/11394] " cgd at google dot com
2010-03-25 0:11 ` drepper at redhat dot com
0 siblings, 2 replies; 4+ messages in thread
From: cgd at google dot com @ 2010-03-17 6:30 UTC (permalink / raw)
To: glibc-bugs
locale-archive files generated on x86_64-linux and i686-linux differ
unnecessarily, due a likely-unintentional hash difference.
they're compatible with each other AFAICT, but they aren't identical when built
fresh (and they easily could be).
to repro:
configure / build glibc for i686-linux and x86_64-linux.
in each, install locale data & create a locale-archive file by doing:
make localedata/install-locales 'SUPPORTED-LOCALES=en_US/ISO-8859-1
en_US.UTF-8/UTF-8'
compare the locale-archive files. They're much the same, but the
_NL_CTYPE_WIDTH tables are different. in particular, some of the early
(high-level) 3level table entries have different order, and thus later data in
the file also differs. However, each is usable/correct.
the wcwidth_table 3level table is constructed by iterating charmap->char_table
(a simple-hash).
the iteration order depends order of entries in the table, which depends on the
compute_hashval hash function (whose result is modded by the table size).
the version of compute_hashval used for simple-hash returns unsigned long int,
and the computed hash value differs between i686 and x86_64, so the 3level table
gets populated in a different order, ...
the hash table in this case doesn't make it to disk, so it's safe to tweak the
return type. (the hashes that use compute_hashval and *do* make it to disk use
uint32_t already.)
while it's not strictly necessary to fix this, it's comforting to see identical
results when building on 32-bit and 64-bit. will attach patch.
--
Summary: locale-archive differs between x86_64-linux and i686-
linux due to unintentional hash difference
Product: glibc
Version: 2.12
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper at redhat dot com
ReportedBy: cgd at google dot com
CC: glibc-bugs at sources dot redhat dot com
GCC build triplet: x86_64-linux
GCC host triplet: x86_64-linux
GCC target triplet: x86_64-linux and i686-linux
http://sourceware.org/bugzilla/show_bug.cgi?id=11394
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^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <bug-11394-131@http.sourceware.org/bugzilla/>]
end of thread, other threads:[~2014-06-30 18:29 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-03-17 6:30 [Bug libc/11394] New: locale-archive differs between x86_64-linux and i686-linux due to unintentional hash difference cgd at google dot com
2010-03-17 6:36 ` [Bug libc/11394] " cgd at google dot com
2010-03-25 0:11 ` drepper at redhat dot com
[not found] <bug-11394-131@http.sourceware.org/bugzilla/>
2014-06-30 18:29 ` fweimer at redhat dot com
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