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Re: [testsuite & dwarf2] How to handle store.exp failure on AMD64?
On Thu, Aug 07, 2003 at 10:58:48AM -0400, Andrew Cagney wrote:
> >On Thu, Aug 07, 2003 at 10:49:59AM +0200, Michal Ludvig wrote:
> >
> >>4) let GDB pretend that all registers have the same value unless said
> >>otherwise later in the .debug_frame and convince GCC to put a note when
> >>their value is overwritten.
> >>
> >>Opinions?
> >
> >
> >See the archives of this list, from about a month ago. I discussed
> >this with Richard but never got around to writing a patch.
>
> And I forgot to commented on the thread also :-(
>
> There are several bugs:
>
> - An architecture should mark a limited set of registers as, for want of
> a better phrase, `always unwind'. System registers, for instance, would
> fall into that category. No preserve registers, however, are a more
> interesting problem.
>
> - GCC should be generate, and GDB should consume, more complete
> variable location information. If a variable isn't preserved across a
> function call then GCC/GDB should report the variable as being unavailable.
I'm not talking about variable location information. I'm talking about
register unwind information; and Richard's claim that the default
should be unmodified makes sense in the context of unwinding.
Variable locations are a different problem. A serious one, maybe, but
unrelated.
> - GCC -O0 should should not eliminate variables, and should preserve all
> variables across function calls.
>
> Given that is compiled with -O0, I think GCC is failing on count #3 here.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer