Re: [PATCH 4/7] Class-fy partial_die_info

[Tom Tromey <tom@tromey.com>]

>> std::is_trivially_destructible to enforce the rule that objects on an
>> obstack can't really be destroyed.  This would eliminate the separate
>> XOBNEW, which is maybe a potential source of errors; and would also make
>> it harder to accidentally add a destructor to objects allocated this way

Yao> but why dtor must be trivial?  We can have "operator new" and "operator
Yao> delete", the former allocate spaces on obstack and the latter doesn't
Yao> de-allocate space.  It doesn't matter dtor is trivial or not.  I may
Yao> miss something here.

My thinking was that if something is allocated on an obstack, then
presumably the destructor will never be run.  So, it's best to avoid
confusion by requiring a trivial destructor.

I suppose it would be possible to track objects and destroy them, but if
that's done, then it sort of eliminates the point of an obstack -- it
would be just as convenient at that point to use the ordinary new.

Yao> Further, I think IWBN to have a  class which has new/delete operator,
Yao> and other classes can inherit it.  What do you think the patch below?

I suppose this makes sense if you know that all objects of a given type
must be allocated on an obstack.

Tom