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To: Nathan Whitehorn <nwhitehorn@freebsd.org>
Subject: Re: clang 3.2 RC2 miscompiles libgcc?
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On 2012-12-27 16:15, Nathan Whitehorn wrote:
> On 12/27/12 09:07, Stefan Farfeleder wrote:
>> I noticed that most of my C++ applications in recent versions of FreeBSD
>> head suddenly crash without me recompiling them. I tracked it down to
>> r243830 which imported a new clang version. The new clang seems to
>> compile libgcc in a wrong or at least incompatible way with what gcc
>> expects. In fact, the breakage only occurs with libgcc compiled by a
>> post-r243830 clang and an application compiled with g++ -O2. For me, the
>> crash happens with boost::program_options, but I'm not sure if that is
>> necessary for the crash.
>
> I've seen what I think is the same thing due to a miscompilation of
> unwind-dw2.c that caused crashes related to cross-shared-object
> exception handling. It seems to have been fixed with the 3.2 release but
> I haven't tested it too thoroughly yet.

I have been playing with Stefan's testcase for a while now, and while I
can reproduce the crashes, I am still at a loss about the cause.  It
does seem to have something to do with throwing exceptions, but I am
still not sure whether I am looking at a bug in boost, gcc, clang, or
libgcc...

Do you happen to have a smaller testcase, by any chance?