Re: C identifier lookup speedups, 2/2

[Zack Weinberg <zack at codesourcery dot com>]

Neil Booth <neil at daikokuya dot co dot uk> writes:

> Zack Weinberg wrote:-
>
>> This half does tag lookups.  It is more invasive than it might
>> otherwise have been, because part of the change is that the C front
>> end no longer puts parameter decls in their own binding contour; they
>> go in the same contour as variables declared at the outermost block
>> scope of a function.
>
> Great!  I could never figure out why we did this, and of course there
> was no comment.  Do you know why?

I think it was originally because of the way the compound statement
production in c-parse.in works, and then it accreted other parts of
the code that expected it to be so.

> I once tried to remove the extra contour, which gave a bootstrappable
> compiler but with screwy debug info IIRC.  At that point I gave up.

I don't think the debug info is screwed by this ... I suppose we'll
find out.

zw