Re: [Mingw-users] g++ 4.2.1 with shared libstdc++ notcatchingexceptions

[Danny S. <dan...@cl...>]

> > 
> > Strange...
> > Is there another way to always force the -shared-libgcc flag ?

I wrote: 
> 
> Unfortunately not without some cost.  The crtbegin object 
> that initializes the EH frame use weak externals to resolve 
> the registration/deregistration functions.  It uses weak 
> symbols so that we pull in in the libgcc modules with all the 
> unwind code only  when we actually need the unwind code -- 
> that is to avoid dead code in non-EH apps.  I did this 
> because in an earlier experiment with DW2, users complained 
> about 'huge' size of their toy apps that didn't need nor want 
> the unwind code.  This  all works as advertised with static 
> libgcc.    However, weak symbols do not work with dlls that 
> are linked via import lib.  So unless we   add 
> -Wl,-u,___register_frame_info -Wl,-u,___deregister_frame_info 
> to make the symbols string EH tables won't be initialized or 
> finalized.  --shared-libgcc adds the magic -u's.
> 

Thanks for reporting, becuase it made think of the problem shtly
differently and indeed ther is a very simple solution to get weak
__register_frame_info,__deregister_frame_info when using static libgcc
and strong externs when using a libgcc.dll.

Just call them from a wrapper that lives in libgcc itself.  The process
of tying together the object files that make a dll automatically forces
all undefined references  to be strong.  

I'm testing an updated libgcc/crtbegin now, so far it works just by
renaming libgcc_s.a to libgcc.dll.a - no need for -shared-libgcc.  With
this setup just adding -Bstatic to command line will revert to using
static libgcc.a 


Danny