Re: LuaThreads with LuaJIT (and maybe lua_tcc)

[Javier Guerra <javier@...>]

On Tuesday 11 April 2006 10:47 am, Jerome Vuarand wrote:
> I'm also planning to use lua_tcc at some point to optimize by hand some
> part of my engine. The principle would be to turn static data of my
> problem into ultra-specific hardcoded C routines that would be almost
> optimal with no cost in data complexity.

i don't want to discourage you, but don't rely too much on lua_tcc.  
unfortunately, it seems TCC has some unclean usage of global variables; so 
it's usable to use it with very static environment (usual C program 
initialisation and such), but might be unstable with a dynamic language 
environment.

in particular, each time you use it to compile some C, lua_tcc allocates a new 
TCC state. this state has to be there as long as you want to use the compiled 
code, so the returned function(s) are closure with a 'hidden' reference to a 
userdata that holds the TCC state.  that way, when the last function is 
disposed, the lua_tcc userdata can be collected and the TCC state 
deallocated; but if you create two TCC states, the first deallocation 
succeeds, and the second one fails (it tries to deallocate some globals 
_again_).

for this, lua_tcc is nice to experiment and try new things; but when you're 
satisfied with your C code, you should use a real compiler.


-- 
Javier

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