Hi, When code is both VM and native it's nice to be able to have both code blocks as a unit because then we can freely compile a function without needing to do graph analysis. It simply makes the life easier to maintain the two setups. And incrementally compile to native on a per uses base and not in one go very much like JIT ing. Also the overhead on the VM side is low but the native execution will of cause be a little bit slower because of an extra indirection. I don't expect the slowdown to be too bad though. Perhaps we could mark the beginning of a code block in a program as
0 -> the rest of the vector is VM code 1 -> the rest of the vector is Native code addr -> there is native code at the addr indirection Then we can skip the expensive extra inderection for native code when suitable. To note here I assume that picking a[0],a[1] is less expensive then a[0],*a[0]. At some stage we may leave the VM and perhaps enter into a Native only mode. Then we can restructure. /Stefan On Mon, Aug 6, 2012 at 11:32 AM, Andy Wingo <wi...@pobox.com> wrote: > On Sun 05 Aug 2012 17:19, Stefan Israelsson Tampe <stefan.ita...@gmail.com> > writes: > > > Probably it is best to have the first qword / dword in the code to be > > 0 or the native adress e.g. I propose to add that feature to the > > rtl-branch. > > Good question! Given the different tradeoffs, that seems workable. > Another possibility would be to use a different TC7 for native > procedures. After all, the only calls we need to make cheaply are > native->native and bytecode->bytecode, and the rest can go through a > general dispatch loop (possibly with inline caching). WDYT? (Also note > that RTL words are 32 bits wide, which may or may not be sufficient for > native code pointers.) > > Andy > -- > http://wingolog.org/ >
