Re: [Mingw-users] gcc and stack unwinding

[Earnie <ea...@us...>]

K. Frank wrote:
> Hi Edward!
> 
> On Tue, May 10, 2011 at 1:38 PM, Edward Diener <eld...@tr...> wrote:
>> I was having problems with the MingW gcc-4.5.2 implementation and some
>> Boost regression tests when someone suggested I try a gcc-4.5.2
>> implementation from TDM-GCC. After trying that version my regression
>> testing problems went away, for what reason I do not know. When I looked
>> to compare the two versions I noticed the MingW version has
>> 'libgcc_s_dw2-1.dll' while the TDM version has 'libgcc_s_sjlj-1.dll'. I
>> believed these have something to do with the stack, and maybe stack
>> unwinding as well as cross-DLL exceptions but I could not find any
>> explanation in the gcc 4.5.2 docs although I thought I saw something
>> there about it previously.
>>
>> Can anyone tell me what these different DLLs are and where in the gcc
>> docs I can find information about them ?
> 
> I don't really understand the details of this, but I do believe they are
> two different implementations of exception handling.
> 

Dwarf-2 unwinding is faster.  If you don't care about catching
exceptions thrown by non-dwarf-2 third party binaries or need to unwind
through a third party binary then it shouldn't matter to you.

It would be nice to be able to -mdwarf-2 or -msjlj but the system
libraries would need to be generated for each and the appropriate ones
chosen.  This might be possible with a modified specs file but would
make maintenance a nightmare.

>>From the tdm web site:
> 
>    http://tdm-gcc.tdragon.net/start
> 

A different POV.  You must choose a package that contains the
appropriate libraries.  MinGW offers only one binary distribution of the
runtime that matches the stack unwinding of its compiler offering.

-- 
Earnie
-- http://www.for-my-kids.com