Re: Performance tracking

[David Kastrup]

Noah Lavine <address@hidden> writes:

>> On Sat, May 5, 2012 at 12:42 PM, David Kastrup <address@hidden> wrote:
>>> Noah Lavine <address@hidden> writes:
>>>
>>>> It appears to me (anecdotally) that most of the build time is spent
>>>> compiling Scheme code, rather than C code.
>>>>
>>>> One idea I had been toying with is whether Guile could compile faster
>>>> if it had another copy of Guile already around, so it could skip the
>>>> portion of compile-time where the interpreter is running the compiler.
>>>
>>> Bootstrap hell.  If the "copy of Guile already around" happens to
>>> produce different code, you have lots of fun ahead.
>
>
> Oh, I was unclear. I meant that the existing copy of Guile would run
> the compiler from the new copy of Guile.

That assumes that it runs it producing a correct result.

> In the worst case you'd have to bootstrap, but that's what we do now,
> every time.

If the "copy of Guile already around" is malicious, bootstrapping from
the produced compilation can't get rid of the malice.  See Ken
Thompson's malicious compiler experiment.

-- 
David Kastrup