[PATCH] [x32] Use ebp/esp as frame and stack pointer

[Derek Schuff]

This area is actually one place where NaCl's 64-bit ABI differs from X32; i.e. NaCl considers the frame and stack pointers as 64 bits, but has special sequences to update them. For the purposes of this patch, instead of just e.g. using isLP64 everywhere in emitPrologue, could we just make the const at the top of be something like Uses64BitFramePtr and have that be the condition?

Splitting into FramePtr vs MachineFramePtr is fine.

http://reviews.llvm.org/D4617