From: Bryce McKinlay <bmckinlay@gmail.com>
To: gcc@gcc.gnu.org, java@gcc.gnu.org,
Jack Howarth <howarth@bromo.med.uc.edu>
Subject: _darwin10_Unwind_FindEnclosingFunction
Date: Mon, 23 Jul 2012 11:24:00 -0000 [thread overview]
Message-ID: <CALUNu-rAQF1da1HT7=nLijCn2kNt6aXaEq1DXqMdUPrRBysVsQ@mail.gmail.com> (raw)
libgcc_s and libgcj contain a hack which renames
_Unwind_FindEnclosingFunction to
_darwin10_Unwind_FindEnclosingFunction on darwin targets. It appears
this was introduced to work around an issue in OS X 10.6 where the
_Unwind_FindEnclosingFunction was implemented as a stub which called
abort(). see: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41991
This has since been fixed in OS X 10.7+, and the system's
_Unwind_FindEnclosingFunction now works.
In Mac OS X 10.7 and 10.8, libgcc_s is installed as a symlink to libSystem:
$ ls -l /usr/lib/libgcc_s.1.dylib
lrwxr-xr-x 1 root wheel 17 Jun 19 13:16 /usr/lib/libgcc_s.1.dylib ->
libSystem.B.dylib
Unfortunately this means that libgcj does not work on a standard Mac
OS X installation, because dyld will see the symlink and resolve
libgcc_s to libSystem before it checks anywhere else:
$ gcj Hello.class --main=Hello
$ ./a.out
dyld: _dyld_bind_fully_image_containing_address() error
dyld: Symbol not found: __darwin10_Unwind_FindEnclosingFunction
Referenced from: /usr/local/lib/libgcj.13.dylib
Expected in: /usr/lib/libSystem.B.dylib
in /usr/local/lib/libgcj.13.dylib
Trace/BPT trap: 5
This can be worked around by adjusting the system library path, or
forcing libgcc_s to be loaded with DYLD_INSERT_LIBRARIES, but libgcj
should work out-of-the-box for without having to hack the dyld
configuration - so clearly we should not be renaming
_Unwind_FindEnclosingFunction on OS X 10.7+ configurations.
But I'm not convinced that this solution was ever really right to
begin with. Even on a 10.6 system, things ought to work so long as you
ensure libgcc_s is loaded before libSystem. Shouldn't the
_darwin10_Unwind_FindEnclosingFunction rename be removed entirely?
Bryce
next reply other threads:[~2012-07-23 11:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-23 11:24 Bryce McKinlay [this message]
2012-07-26 13:44 ` _darwin10_Unwind_FindEnclosingFunction Jack Howarth
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