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Subject: [Bug c++/99215] coroutines: debugging with gdb
Date: Wed, 24 Feb 2021 15:23:56 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99215

--- Comment #6 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Nils Gladitz from comment #5)
> Apparently when the coroutine happens to be a member function (even a sta=
tic
> one) printing *frame_ptr results in "{<No data fields>}".
>=20
> Ideally I'd want to have non-static member coroutines and would like to be
> able to inspect the "this" pointer during debugging.

.. 'this' gets translated into a reference to the original object for
coroutines... hmm have to see if there's any useful advice at this stage.

> I was also wondering if "frame_ptr" as a non-reserved name isn't problema=
tic
> in case there happens to be e.g. a local variable with that name.

the local variables in the ramp are prefixed with 'coro.' which makes them =
not
a legal user identifiers.  So it's actually coro.frame_ptr.

(where there is potential for clashes, frame variables named are pushed into
the implementation space e.g. __ or _CapitalLetter).

=3D=3D=3D

I should check in the actor/destroyer if there is scope for a clash (since =
the
variables are local, they are named xxxxxactor:frame_ptr)

.. and would be distinct from any var named frame_ptr in the original sourc=
e ..
which would become  xxxxxactor:frame_ptr->frame_ptr :)=20

However, when implementing the "idea" described above, I think that might
expose the issue - so prefixing with __ or changing the name to _Frame_ptr
might be necessary.

Of course, I didn't make a test case to prove this, .. but will try it
sometime.=