refactor pp_tied

remove some redundant code regarding stack handling

-removed:
  -4/-8 pop on SP
  +4/+8 push on SP
  PUTBACK

function's machine code size dropped from 0xC5 to 0xBD bytes on VC2003

diff --git a/pp_sys.c b/pp_sys.c
index b445ee2..41a315d 100644 (file)
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -1005,21 +1005,23 @@ PP(pp_tied)
     dVAR;
     dSP;
     const MAGIC *mg;
     dVAR;
     dSP;
     const MAGIC *mg;

-    SV *sv = POPs;
+    dTOPss;

     const char how = (SvTYPE(sv) == SVt_PVHV || SvTYPE(sv) == SVt_PVAV)
                ? PERL_MAGIC_tied : PERL_MAGIC_tiedscalar;
 
     if (isGV_with_GP(sv) && !SvFAKE(sv) && !(sv = MUTABLE_SV(GvIOp(sv))))
     const char how = (SvTYPE(sv) == SVt_PVHV || SvTYPE(sv) == SVt_PVAV)
                ? PERL_MAGIC_tied : PERL_MAGIC_tiedscalar;
 
     if (isGV_with_GP(sv) && !SvFAKE(sv) && !(sv = MUTABLE_SV(GvIOp(sv))))

-       RETPUSHUNDEF;
+       goto ret_undef;

 
     if (SvTYPE(sv) == SVt_PVLV && LvTYPE(sv) == 'y' &&
 
     if (SvTYPE(sv) == SVt_PVLV && LvTYPE(sv) == 'y' &&

-       !(sv = defelem_target(sv, NULL))) RETPUSHUNDEF;
+       !(sv = defelem_target(sv, NULL))) goto ret_undef;

 
     if ((mg = SvTIED_mg(sv, how))) {
 
     if ((mg = SvTIED_mg(sv, how))) {

-       PUSHs(SvTIED_obj(sv, mg));
-       RETURN;
+       SETs(SvTIED_obj(sv, mg));
+       return NORMAL; /* PUTBACK not needed, pp_tied never moves SP */

     }
     }

-    RETPUSHUNDEF;
+    ret_undef:
+    SETs(&PL_sv_undef);
+    return NORMAL;

 }
 
 PP(pp_dbmopen)
 }
 
 PP(pp_dbmopen)