[Lightning] Re: Argument Management

[Sandro Magi]

On Wed, Feb 20, 2008 at 1:50 AM, Paolo Bonzini <address@hidden> wrote:
 >  > Does this mean that I can't write a VM which performs interprocedural
 >  > register allocation using GNU Lightning? Or is this statement intended
 >  > to apply only when using the C call convention?
 >
 >  It's mostly because of the SPARC, which uses register windows.  If you
 >  don't care about it, you can pass parameters using GPR.

 I don't want to break compatibility unnecessarily. I'll read up on Sparc:
 http://www.sics.se/~psm/sparcstack.html

 Perhaps an additional macro to be defined by each arch is warranted.
 Something like: JIT_NEEDS_PROLOG. If false, I can use a different
 calling convention.


 >  The way I worked around it in GNU Smalltalk was to run the whole
 >  interpreter in "continuation-passing style".  Which is, in fact, a
 >  different calling convention than the standard one.

 I've considered CPS, particularly in conjunction with the Cheney on
 the MTA-style GC. Unfortunately, CPS just kills the pipeline due to
 the indirect function calls. Given how deep pipelines are nowadays,
 and the fact that they're getting deeper, I'm reluctant to go this
 way.

 Sandro