Faster feature checks

Perform only a bit check instead of a much more expensive hash
lookup to test features.

For now I've just added a U32 to the cop structure to store the bits,
if we need more we could either add more bits directly, or make it a
pointer.

We don't have the immediate need for a pointer that warning do since
we don't dynamically add new features during compilation/runtime.

The changes to %^H are retained so that caller() can be used from perl
code to check the features enabled at a given caller's scope.

1 files changed, 3 insertions, 0 deletions

diff --git a/pp_ctl.c b/pp_ctl.c
index 5bd9376b03..ec08078d2a 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -33,6 +33,7 @@
 #include "EXTERN.h"
 #define PERL_IN_PP_CTL_C
 #include "perl.h"
+#include "feature.h"
 
 #define RUN_PP_CATCHABLY(thispp) \
     STMT_START { if (CATCH_GET) return docatch(thispp); } STMT_END
@@ -3485,6 +3486,7 @@ S_doeval_compile(pTHX_ U8 gimme, CV* outside, U32 seq, HV *hh)
     if (clear_hints) {
 	PL_hints = 0;
 	hv_clear(GvHV(PL_hintgv));
+        CLEARFEATUREBITS();
     }
     else {
 	PL_hints = saveop->op_private & OPpEVAL_COPHH
@@ -3502,6 +3504,7 @@ S_doeval_compile(pTHX_ U8 gimme, CV* outside, U32 seq, HV *hh)
 	    /* SAVEHINTS created a new HV in PL_hintgv, which we need to GC */
 	    SvREFCNT_dec(GvHV(PL_hintgv));
 	    GvHV(PL_hintgv) = hh;
+            FETCHFEATUREBITSHH(hh);
 	}
     }
     SAVECOMPILEWARNINGS();