Re: Proposal: block-based vector allocator

[Eli Zaretskii]

> Date: Fri, 01 Jun 2012 17:32:54 -0700
> From: Paul Eggert <address@hidden>
> CC: Dmitry Antipov <address@hidden>, address@hidden, 
>  Eli Zaretskii <address@hidden>
> 
> This whole area is in a bit of a mess.  It's not just
> that comment.  While looking into this and cleaning it up
> I also found the following:
> 
>  * The union data structure depends on WORDS_BIGENDIAN
>    for no particularly good reason nowadays, and this just
>    confuses things.
> 
>  * The w32heap code is confused about this, and thinks that
>    USE_LISP_UNION_TYPE invalidates USE_LSB_TAG, which maybe
>    used to be true but is no longer true.
> 
>  * There's no way for the builder to force a build
>    without USE_LSB_TAG (Dmitry's point).
> 
>  * There are a few annoying warnings if you compile unions
>    with gcc -Wall.
> 
> You can find the patch for all this at
> <http://bugs.gnu.org/11604>.  I'll CC: Eli
> since this affects w32 code.

Unfortunately, that patch does nothing IMO to reduce "the mess".  To
reduce the mess, we should add commentary that would replace wading
through twisty macros all alike with reading clear descriptions in
plain English.  By contrast, the patch doesn't add any documentation,
it actually _removes_ some of the comments.

In this situation, saying that w32heap.c is "confused" is really being
facetious, to say the least.