Re: [PATCH 1/3] gdb/python: add type traits check for all PyObject sub-classes

[Tom Tromey <tom@tromey.com>]

>>>>> "Andrew" == Andrew Burgess <aburgess@redhat.com> writes:

Andrew> The problem is that Python is written in C, and PyObject_New doesn't
Andrew> call any constructors for `some_new_type`, nor for any of the fields
Andrew> within `some_new_type`.

Since working on the Python safety series, I have been wondering if we
could remedy this.  That is, give gdb's classes constructors and
destructors and arrange for these to be called in-place in tp_init /
whatever the destroy one is.

This way we could use idiomatic gdb code, which would be safer.

I was planning to investigate this more deeply once Matthew Longo's work
was done, since I didn't want to touch all the type objects and cause
conflicts.

Andrew> +
Andrew> +template <typename T>
Andrew> +struct is_python_allocatable {
Andrew> +  static constexpr bool value =
Andrew> +    std::is_trivially_destructible_v<T> &&
Andrew> +    std::is_trivially_copyable_v<T>;

Brace and operator placement.

Otherwise this looks good to me.

If the tp_init experiment works out I suppose we may end up reverting
this.  But IMO it's best not to wait on something that might not happen.

Approved-By: Tom Tromey <tom@tromey.com>

Tom