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, 5 insertions, 0 deletions

diff --git a/proto.h b/proto.h
index 59080ec33a..d106187ef2 100644
--- a/proto.h
+++ b/proto.h
@@ -6597,6 +6597,11 @@ PERL_CALLCONV struct refcounted_he *	Perl_store_cop_label(pTHX_ struct refcounte
 #define PERL_ARGS_ASSERT_STORE_COP_LABEL	\
 	assert(label)
 
+PERL_CALLCONV HV *	Perl_get_isa_hash(pTHX_ HV *const stash)
+			__attribute__nonnull__(pTHX_1);
+#define PERL_ARGS_ASSERT_GET_ISA_HASH	\
+	assert(stash)
+
 
 END_EXTERN_C
 /*