[patch] support -gdwarf-2 when creating cygwin1.dbg

Brian Dessent brian@dessent.net
Wed Apr 18 13:18:00 GMT 2007


Christopher Faylor wrote:

> Thanks for doing this.  Please check in.  Can we switch to dwarf-2 by
> default in the cygwin makefile(s)?

I thought about that, but the problem is anything you do to *FLAGS in
winsup/cygwin won't affect flags used in the other dirs like libiberty
or newlib, and so unless you set CXXFLAGS and CFLAGS when you do
toplevel configure, you'll end up with a mish-mash of some stabs and
some DW2 in the .dbg file.

Corinna Vinschen wrote:

> As long as we use a 3.x or 4.0.x gcc it should be ok.  Later gcc's
> explicitely switch off the generation of a DW_CFA_offset column in the
> .debug_frame CIE header information, which breaks backtracing in GDB.

Hmm, I think I read something about that on the gcc list.  Is this just
a case of gcc switching to doing TheActualRightThing and gdb not having
being updated yet?

> There's an explicit
> 
> #define DWARF2_UNWIND_INFO 0
> 
> in gcc/config/i386/cygming.h right now.  The accompanying comment is

Aren't we talking about two different things here?  That's for unwinding
during exception handling, but you can still leave that at 0 (and use
--enable-sjlj-exceptions) and still get the benefit of -gdwarf-2 for
gdb's consumption.

Brian



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