I originally posted this as a follow-up to the named anonymous subs thread, but a monk of greater standing than I suggested that I might generate a little more heat if I started a new thread here. So...

As maintainer of Class::MethodMaker, I have more than a passing interest in this technique: C::MM generates anonymous routines by the bucket-load, and as well as debugging, I'm particularly interested in profiling, too.

I'd been meaning to do something about this for a couple of years now, and this thread finally galvanized me into action. After two days of tinkering with it, and several false starts, I've finally come up with this XS incantation:

  void
  set_sub_name(SV *sub, char *pname, char *subname, char *stashname)
    CODE:
      CvGV((GV*)SvRV(sub)) = gv_fetchpv(stashname, TRUE, SVt_PV);
      GvSTASH(CvGV((GV*)SvRV(sub))) = gv_stashpv(pname, 1);
      GvNAME(CvGV((GV*)SvRV(sub))) = savepv(subname);
      GvNAMELEN(CvGV((GV*)SvRV(sub))) = strlen(subname);

[download]

The pname is the package name, the subname the subname, and stashname is the name of a stash to generate to attach the code to, to avoid overwriting the original stash (which is the package the code was compiled in), or the ANON entry in the pname stash. The above certainly appears to work, both with stack traces & the profiler, and doesn't break my code. I was concerned that generating a new stash for each subr might hurt the memory consumption, but empirical testing suggests that the effect is minimal-to-nil.

I'm no XS programmer, so I'd appreciate any constructive feedback anyone has.

In reply to Naming Anonymous Subs by fluffy

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