Re: Type safe vector API

[Mark Mitchell <mark at codesourcery dot com>]

Nathan Sidwell wrote:

> Hi,
> Here's a patch which implements a type safe vector API, and a separate 
> patch
> which applies it to the CLASSTYPE_VBASECLASSES.
>
> The basic idea is that you define a vector of pointers with
>     DEF_VEC_P(typedef)
> and a vector of objects with
>     DEF_VEC_O(typedef)
> these produce a structure declaration and a set of inline functions to
> manipulate the vector.
>
> You define a pointer to vector object with
>     VEC(typedef) *v;
> and away you go. You have to deal with pointers to vectors, as
> the implementation uses the trailing array hack.  There is an API
> call to allow you to have a structure ending with a vector member
> (something that would be useful for a BINFO or TEMPLATE_ARG_VEC).
>
> I couldn't measure time or size difference with this patch, as I
> didn't have a testcase with significant virtual bases.
>
> ok?

I've been waiting to see if someone else would comment.

To me, this looks fine.  I'm a little nervous about the way in which 
you're using the API for CLASSTYPE_VBASECLASSES in that it looks like 
you're conservatively estimating the size of the vector, so it might not 
actually be a win over the TREE_LIST thing we have now.   As you say, 
however, this is a tiny amount of memory one way or the other.

You need comments on some of the functions; for example, macro_input.

If nobody objects in another 24 hours, please go ahead and check this 
in.  Hopefully the tree-ssa folks can make use of this for their 
purposes as well.

--
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com