Add SS_ADD_* macros and replace most SSPUSH* uses

The current idiom for adding an entry to the savestack is

    SSCHECK(3);
    SSPUSHINT(...);
    SSPUSHPTR(...);
    SSPUSHUV(SAVEt_...);

Replace this with a new idiom:

    {
        dSS_ADD;
        SS_ADD_INT(...);
        SS_ADD_PTR(...);
        SS_ADD_UV(SAVEt_...);
        SS_ADD_END(3);
    }

This is designed to be more efficient.

First, it defines some local vars, and defers updating PL_savestack_ix
to the end.

Second, it performs the 'is there space on the stack' check *after*
pushing. Doing the check last means that values in registers will have
been pushed and no longer needed, so don't need saving around the call to
grow. Also, tail-call elimination of the grow() can be done. These changes
reduce the code of something like save_pushptrptr() to half its former
size.

Of course, doing the size check *after* pushing means we must always
ensure there are SS_MAXPUSH free slots on the savestack */

1 files changed, 7 insertions, 6 deletions

diff --git a/sv.c b/sv.c
index 35d295e7d5..397d9928df 100644
--- a/sv.c
+++ b/sv.c
@@ -3795,13 +3795,14 @@ S_glob_assign_ref(pTHX_ SV *const dstr, SV *const sstr)
 	       gain a name somehow before leave_scope. */
 	    if (stype == SVt_PVCV) {
 		/* There is no save_pushptrptrptr.  Creating it for this
-		   one call site would be overkill.  So inline the ss push
+		   one call site would be overkill.  So inline the ss add
 		   routines here. */
-		SSCHECK(4);
-		SSPUSHPTR(dstr);
-		SSPUSHPTR(location);
-		SSPUSHPTR(SvREFCNT_inc(*location));
-		SSPUSHUV(SAVEt_GVSLOT);
+                dSS_ADD;
+		SS_ADD_PTR(dstr);
+		SS_ADD_PTR(location);
+		SS_ADD_PTR(SvREFCNT_inc(*location));
+		SS_ADD_UV(SAVEt_GVSLOT);
+		SS_ADD_END(4);
 	    }
 	    else SAVEGENERICSV(*location);
 	}