Re: [PATCH 1/4] New gdb arch hook: return_with_first_hidden_param_p

Joel Brobecker
2012-05-14T17:15:17Z

> > Can we use the fact that functions that have their first parameter
> > be a nameless, artificial, paramter whose type is a pointer to
> > the return type? Or would this heuristics trigger in other situations?
>
> Yeah, I thought of that heuristics, but it still can't differentiate
> passing 3 or 4 parameters.

So, you are saying that we have functions who have an extra hidden
parameter used for something other than the function's return value?

> Well, we have to compromise :) Could you please re-consider this patch
> series, as it is a trade-off, and not perfect?
>
> If this patch series is still not acceptable, we may create a variant
> (or sub-class) of gnu-v3-abi, say "gnu-v3-pass-implicit-param" or
> something similar, for targets affected by this problem, and
> `set_cp_abi_as_auto_default ("gnu-v3-pass-implicit-param")' in each
> target backend. (This is my rough thought, and need some experiments to
> see it works or not). Even, if GCC in the future starts to pass
> implicit parameter for these ports, we can switch to gnu-v3, and users
> just have to type `set cp-abi gnu-v3' without rebuilding their GDB.

I'm not very familiar with the gnu-v3-abi... If we've explored
all avenues with trying to use the debug info, I'm satisfied with
the next best thing, which could possibly be your initial set of
patches. I'd like someone else to be involved in the review,
however, just to get someone else's opinion.

--
Joel