RE: conditional compilation of debug facilities in LUA core

[Benoit Germain <bgermain@...>]

I have run a modified life.lua 

> -----Original Message-----
> From: Benoit Germain [mailto:bgermain@ubisoft.fr]
> Sent: lundi 9 septembre 2002 12:36
> To: Multiple recipients of list
> Subject: RE: conditional compilation of debug facilities in LUA core
> 
> 
> Well, I have added a few 
> 
> #ifdef LUA_REFLEXIVEDEBUG
> 
> all over the code (41 places are touched). I don't know about 
> performance,
> but I have a 8K code size reduction because of this. In 
> itself it justifies
> the change, to my mind.
> A script of mine, where no error should occur, still runs fine :-).
> 
> The changes are as follows:
> 
> - removed support for hooks and setjmp/longjmp from the 
> lua_State structure
> - lua_Debug structure keeps only its i_ci field
> - several error checking functions are redefined as empty macros
> 
> However, since I have no deep knowledge of the core's 
> internals, I cannot
> guarantee that it is truly operational.
> Maybe someone would care to have a look ?
> 
> Cheers,
> 
> Benoit.
> 
> 
> > -----Original Message-----
> > From: Benoit Germain [mailto:bgermain@ubisoft.fr]
> > Sent: lundi 9 septembre 2002 09:28
> > To: Multiple recipients of list
> > Subject: RE: conditional compilation of debug facilities in LUA core
> > 
> > 
> > I am not working in an environment where the measures I could do are
> > significant (W2K, to name it). Also, measures on an 
> > intel-based system with
> > a few hundred Kb of L1 cache might not provide information as 
> > to the gain we
> > get, say, on a R5900 core with 8K of L1 code cache :-)
> > And I haven't yet had the time to do it, but I am going to 
> > take it real
> > soon.
> > 
> > Cheers,
> > 
> > Benoit.
> > 
> > > -----Original Message-----
> > > From: Jani Kajala [mailto:jani@sumea.com]
> > > Sent: vendredi 6 septembre 2002 19:34
> > > To: Multiple recipients of list
> > > Subject: Re: conditional compilation of debug facilities 
> in LUA core
> > > 
> > > 
> > > Hi,
> > > 
> > > Have you profiled the difference in your application? How 
> much more
> > > performance you get by removing the debug stuff?
> > > 
> > > 
> > > Regards,
> > > Jani Kajala
> > > 
> > > ----- Original Message -----
> > > From: "Benoit Germain" <bgermain@ubisoft.fr>
> > > To: "Multiple recipients of list" <lua-l@tecgraf.puc-rio.br>
> > > Sent: Friday, September 06, 2002 5:10 PM
> > > Subject: conditional compilation of debug facilities in LUA core
> > > 
> > > 
> > > > Hi all (well, game developers might be more specifically 
> > > concerned, I
> > > think)
> > > >
> > > > I was thinking that when using LUA as a scripting extension 
> > > for a game,
> > > once
> > > > the scripts are debugged they will not change, because 
> > the scripting
> > > engine
> > > > won't be exposed to the player (unless you use LUA as a 
> > > console language).
> > > > In that case, all the debug stuff is no longer necessary, 
> > > as well as the
> > > > hook mechanism. Therefore, in order to make LUA leaner and 
> > > faster, it
> > > might
> > > > be interesting to be able to compile the core with all 
> this being
> > > disabled.
> > > > Of course the setjmp/longjmp mechanism should remain, but 
> > > testing for a
> > > > count hook at each VM instruction, and keeping 
> lua_Debug structure
> > > pointers
> > > > in some places is something I would want to be able to 
> > control, for
> > > example
> > > > by commenting out a -DLUA_REFLEXIVEDEBUG directive in the 
> > > config file...
> > > >
> > > > I guess this shouldn't be too much work for anybody, but if 
> > > this could
> > > > become a feature of the official lua distribution, it would 
> > > spare many of
> > > us
> > > > the throes of despair at not having found all the places to 
> > > touch, and of
> > > > doing all this all over again when upgrading.
> > > >
> > > > I suppose that it would mean that the associated compiler 
> > > would be unable
> > > to
> > > > generate unstripped bytecode files, and that a virtual 
> > > machine without
> > > debug
> > > > facilities would have to fail gracefully upon being handled 
> > > a precompiled
> > > > file with debug infos (even if crashing would'nt bother me 
> > > too much).
> > > >
> > > > Anybody with me to convince the authors to include this 
> > > feature in 5.0
> > > final
> > > > :-) ?
> > > >
> > > > Cheers,
> > > >
> > > > Benoit.
> > > >
> > > 
> > 
>