Hello Andy and Mark, Thanks for the review! There has actually been more progress since I pushed that branch. I hit a point in the CPS->RTL stuff where I had trouble because I didn't know how to do things (like mutable variables) in RTL. So I've actually ported the compiler to GLIL in a branch on my computer. I also have a working Tree-IL->CPS compiler for some of Tree-IL (it's not done yet).
I thought that might be a better way forward because CPS and RTL are, to a certain extent, separate ideas. I'll push my wip-cps branch, which contains a Tree-IL->CPS compiler and a CPS->GLIL compiler. What I'm working on now is actually how to represent mutable variables in CPS. I think having explicit environment structures would be nice (and fit with Kennedy's paper), but I haven't figured out the details yet. I realize it might be confusing to start with CPS->RTL, then switch to CPS->GLIL, then switch back later when the RTL branch is ready. If you'd rather do it that way, we can skip the CPS->GLIL phase. Some thoughts: * Yes, passes might be good. I had thought of writing some generic control-flow operators like 'compute-fixpoint' and then writing other things in terms of those. * Using tree-il first sounds good to me. * I also think that CPS should have some construct which says 'do these things in any order'. I haven't put one in yet, mostly because the compiler wouldn't take advantage of it anyway. Noah On Thu, Jan 24, 2013 at 5:38 AM, Nala Ginrut <nalagin...@gmail.com> wrote: > Are you guys going to use CSP to implement SSA for AOT? > 在 2013-1-24 PM6:36，"Andy Wingo" <wi...@pobox.com>写道： > > Hi! >> >> On Thu 24 Jan 2013 10:28, Mark H Weaver <m...@netris.org> writes: >> >> > The problem is that CPS fixes the order in which everything is >> > evaluated, such as the order in which procedure arguments are >> > evaluated, the order in which 'let' or 'letrec' initializers are >> > evaluated, etc. The fact that these orders are unspecified in the >> > direct-style gives the compiler freedom to choose an order that >> > generates the best code, and apparently this freedom can often result >> > in significant gains. Such ordering decisions must be made before the >> > conversion to CPS. >> >> Agreed with the sentiment; however, two points: >> >> * we can have a CPS with let / letrec / * operators that bind a number >> of values in unspecified order, and have a pass later that fixes >> their order. >> >> * code motion passes like CSE depend on effects analysis, and can >> often commute some operations >> >> Anyway, violent agreement! >> >> Cheers, >> >> Andy >> -- >> http://wingolog.org/ >> >>
