Create a direct lookup hash for ->isa() lookup, by retaining the

de-duping hash used by S_mro_get_linear_isa_dfs(). Provide a new
function Perl_get_isa_hash() to lazily retrieve this. (Which could
actually be static if S_isa_lookup() and Perl_sv_derived_from()
moved into mro.c.) Make S_isa_lookup() use this lookup hash in place
of a linear walk of the linear isa. This should turn isa lookups from
O(n) to O(1), which should make heavy users of ->isa() faster.
(eg PPI, and hence Perl Critic).

p4raw-id: //depot/perl@34354

1 files changed, 1 insertions, 0 deletions

diff --git a/hv.h b/hv.h
index e7d0c762ff..7f96a1357b 100644
--- a/hv.h
+++ b/hv.h
@@ -52,6 +52,7 @@ struct mro_meta {
     U32     cache_gen;       /* Bumping this invalidates our method cache */
     U32     pkg_gen;         /* Bumps when local methods/@ISA change */
     const struct mro_alg *mro_which; /* which mro alg is in use? */
+    HV      *isa;            /* Everything this class @ISA */
 };
 
 /* Subject to change.