hi, there!
On Fri, 25 Aug 2000, Bryan K. Ogawa wrote:
> 1. I had seen an email in the mailing list archives which asserted that
> C++ exceptions have been broken since August 1999 in the multithread case
> -- does anyone know what the status in 4.1-STABLE and -CURRENT are? I've
> managed to get the code to compile under FreeBSD, but it crashes quite
> rapidly after this, and I'm wondering if it's because of an exception
> being thrown. This is under 4.1-RELEASE.
this issue is unrelated to threads. FreeBSD stock g++ 2.95.2 compiler
uses -fsjlj-exceptions mechanism for exception handling which is broken
(g++ sometimes generates incorrect code even without any optimization
options given). It is not FreeBSD-specific behaviour. gcc GNATS has
bug report with similar gcc behaviour under OS/390.
uou can still use /usr/ports/lang/egcs -- this is the same
2.95.2 but it uses DWARF2 unwinding info for exception handling -- the
same mechanism that is used by default under Linux and (IIRC) Solaris. I
believe that FreeBSD g++ will switch to this scheme in near future.
I have initial set of patches that adds support to FreeBSD CRT startups
for loading info from .eh_frame ELF sections needed for DWARF2 unwinding
info mechanism to work. David O'Brien has all the information. I think he
can shed some light on this issue (he is gcc/binutils maintainer) but he
seems to be busy with other tasks -- I still haven't got any replies
from him except "go ahead, it would be nice to have this feature" :)
> 2. Sometimes, the programs crash at startup, but not always. I seem to
> recall a recent discussion about the loader not being multi-thread safe --
> was this fixed in time for 4.1-RELEASE ?
yes, I beleive
/fjoe
PS you will also have problems with shared libraries debugging
(see PR/20373). I have solution for this problem too.
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