------- Additional Comments From dberlin at gcc dot gnu dot org 2005-03-16
04:25 -------
Subject: Re: [4.0/4.1 Regression] GCC produces wrong dwarf2
output that breaks gdb
On Wed, 2005-03-16 at 03:54 +0000, wilson at gcc dot gnu dot org wrote:
> ------- Additional Comments From wilson at gcc dot gnu dot org 2005-03-16
> 03:54 -------
> Part of the problem here is the way that declare_in_namespace works.
> gen_variable_die, calls declare_in_namespace, which checks to see if the
> variable has a namespace, and if so emits it into that namespace.
> declare_in_namespace then returns, and gen_variable_die finishes normally,
> which
> means we end up with DIEs for one variable. The local one in the current
> context, and the one emitted into the namespace. The variable in question
> here
> has a namespace of "::".
>
> When we process the abstract instance of f, we emit a local die for i into f,
> and a namespace one into :: the global context. This one has line 3. Then we
> see the global redeclaration, and emit another die into the global context.
> This one has line 6. Then when we handle the function main, we see the
> inlined
> version of f, and we get a decl of i with an abstract origin pointing at the
> function f, and emit two more dies, one local one in the inlined version of f
> that points at the abstract instance of f, and one global one that also points
> at the abstract instance of f. This last one is very wrong. Note that there
> are 5 dies not 4 as I claimed earlier, I missed the one in 'main' when I was
> counting them.
>
> It seems very silly to try to emit a namespace version of a decl with an
> abstract origin. One possible solution is for declare_in_namespace to ignore
> any decl with an abstract origin. If I try this, I get only 4 dies, and gdb
> is
> happy. We still have two global dies, with different line numbers, but we can
> live with that for now.
>
I'm pretty sure declare_in_namespace was something either jason wrote
with my help, or i wrote with jason's help (i can't remember), and i'm
pretty sure this problem didn't occur to either of us.
I agree that outputting a namespace version of an inline die with an
abstract origin is indeed silly, since i don't believe it could possibly
be the one that actually belongs in that namespace (which would be
whatever the actual abstract origin points to).
> I haven't yet tried to trace the history of this, to determine what change
> caused the problem to appear. There might be something else wrong here.
>
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19769
