Re: problems parsing dwarf frame info on amd64 optimized code

[Jim Wilson <wilson at specifixinc dot com>]

Max Asbock wrote:
> The parser works correctly in unoptimized code that uses frame pointers.
> When I turn on the -O flag things fall apart. This is with gcc 3.2.2.

Try a newer gcc version, or a gcc from the development tree.  Maybe 
something has been fixed.

The dwarf unwind info is only used by the gcc builtin dwarf unwinder, 
and the semantics are pretty much defined by what the gcc unwinder does. 
 If the gcc unwinder is working, then step through it to see how it works.

It is possible that the dwarf2 unwind info is not sufficiently detailed 
for all libunwind features to work.  We generally only emit enough info 
for C++ EH to work, which means we need consistent unwind info at call 
points, but not anyplace else.  In particular, most ports do not emit 
unwind info for epilogues.  I think only IA-64 does at the moment, and 
it doesn't use dwarf unwind info.  We do emit unwind info for prologues 
as that is useful for gdb.
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com