On Sun, 5 Dec 2010 17:02:37 +0100 "CUOQ Pascal" <pascal.c...@cea.fr> wrote:
> ygrek wrote: > > > BTW, while we are on this topic, why the following is not in upstream yet? > > > > http://eigenclass.org/R2/writings/optimizing-caml_modify > > > > Looks like a clear win-win without drawbacks (increased code size shouldn't > > be significant > > cause Modify is only used in a couple of places). What do you think? > > This is very interesting. Thanks for pointing it out. Sorry to be nitpicking, but... IIRC, there might be some rare occasions where the Modify macro could be called several times in a C routine. And then you've got several caml_modify_maybe_add_to_ref_table labels in the same C routine. With GCC, you could use a local __label__ http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html but if you want to be portable to non GCC compilers, you'll need a Modify macro which generates a unique label (perhaps using __LINE__ for that purpose). I am thinking of something like [UNTESTED CODE] #define Modify(fp, val) Modify_at(fp, val, __LINE__) #define Modify_at(fp, val, lin) do{ \ value in_heap = 0; \ value _old_ = *(fp); \ *(fp) = (val); \ if (caml_gc_phase == Phase_mark) { \ if (Is_in_heap (fp)) { \ caml_darken (_old_, NULL); \ in_heap = 1; \ goto caml_modify_maybe_add_to_ref_table##Lin; \ } \ } else { \ caml_modify_maybe_add_to_ref_table##Lin: \ if (Is_block (val) && Is_young (val) \ && ! (Is_block (_old_) && Is_young (_old_)) && \ (in_heap || Is_in_heap (fp)) ){ \ if (caml_ref_table.ptr >= caml_ref_table.limit){ \ CAMLassert (caml_ref_table.ptr == caml_ref_table.limit); \ caml_realloc_ref_table (&caml_ref_table); \ } \ *caml_ref_table.ptr++ = (fp); \ } \ } \ }while(0) Cheers. -- Basile STARYNKEVITCH http://starynkevitch.net/Basile/ email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359 8, rue de la Faiencerie, 92340 Bourg La Reine, France *** opinions {are only mine, sont seulement les miennes} *** _______________________________________________ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
