[LLVMdev] JIT allocates global data in function body memory

Reid Kleckner rnk at mit.edu
Tue Jun 30 15:59:47 PDT 2009


> I presume (hope, really) that we don't end up with code and data in the
> same page.  From
> Intel® 64 and IA-32 Architectures Optimization Reference Manual:
> Assembly/Compiler Coding Rule 57. (H impact, L generality) Always put
> code and data on separate pages.

Hahaha, nope.  So this change could actually be a performance win!

Dale, here's a preliminary patch:
http://codereview.appspot.com/90053 (also attached)

Would this kind of change be acceptable to your mysterious client who
won't fully disclose their requirements?  All they have to do is flip
a static boolean flag (it's ugly, I know, but I wanted it to be easy
to change programmatically so a CLI flag takes more work).

Reid
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