Re: FYI: No JIT on Windows 8 for ARM

  • From: Joshua Ballanco <jballanc@xxxxxxxxx>
  • To: luajit@xxxxxxxxxxxxx
  • Date: Thu, 10 May 2012 18:21:06 +0300

On Thursday, May 10, 2012 at 3:25 PM, Mike Pall wrote:
> Joshua Ballanco wrote:
>  
>  
> > would a workaround like the one used by
> > imp_implementationWithBlock work? More details here:
> > http://landonf.bikemonkey.org/code/objc/imp_implementationWithBlock.20110413.html
> >  
>  
>  
> This only works for trampolines with fixed code, where you can
> remap the trampoline code pages and attach it to different data.
> But you can't generated arbitrary code, which is what a JIT
> compiler really needs to do.
>  
>  

Thanks for the great explanation! So, curiosity has gotten the better of me… I 
realize this is completely impractical for LuaJIT, but would it be possible (in 
theory) to combine something like the trampolines from 
imp_implementationWithBlock with Return-oriented Programming (possibly with the 
benefit of a pre-built page containing common code sequences) to achieve 
something like a JIT compiler?  

More importantly, if the answer is yes: why on earth would anyone think that 
locking down memory pages is a good idea?

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