Re: Benchmarking temporary Lisp objects [Was: Re: [RFC] temporary Lisp_Strings]

[Dmitry Antipov]

On 09/05/2014 08:24 AM, Stefan Monnier wrote:

> Your benchmark for `cons' showed that there's some potential benefit,
> but then we have to figure out which Fcons calls can be replaced by
> alloca ones, and then assess whether the result is worth the effort
> (and the risk, since such alloca-allocated thingies need to be handled
> with care, making sure they can't escape to Elisp, and also using the
> stack more intensively increases the risk of crashing into the
> stack depth limit).

Surely this is a bit risky and requires careful looking how this object is
used.  On the other side, it's not too hard to debug; use of local object
outside of its scope causes the very likely eassert/crash at next GC, and
the fault address is very different from what we see with heap objects.

Dmitry