wrap op_sibling field access in OP_SIBLING* macros

Remove (almost all) direct access to the op_sibling field of OP structs,
and use these three new macros instead:

    OP_SIBLING(o);
    OP_HAS_SIBLING(o);
    OP_SIBLING_set(o, new_value);

OP_HAS_SIBLING is intended to be a slightly more efficient version of
OP_SIBLING when only boolean context is needed.

For now these three macros are just defined in the obvious way:

    #define OP_SIBLING(o)          (0 + (o)->op_sibling)
    #define OP_HAS_SIBLING(o)      (cBOOL((o)->op_sibling))
    #define OP_SIBLING_set(o, sib) ((o)->op_sibling = (sib))

but abstracting them out will allow us shortly to make the last pointer in
an op_sibling chain point back to the parent rather than being null, with
a new flag indicating whether this is the last op.

Perl_ck_fun() still has a couple of direct uses of op_sibling, since it
takes the field's address, which is not covered by these macros.

1 files changed, 9 insertions, 9 deletions

diff --git a/pp_ctl.c b/pp_ctl.c
index 6c5ccf5698..b25905d369 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -1811,7 +1811,7 @@ PP(pp_caller)
 	PUSHTARG;
     }
     mPUSHs(newSVpv(OutCopFILE(cx->blk_oldcop), 0));
-    lcop = closest_cop(cx->blk_oldcop, cx->blk_oldcop->op_sibling,
+    lcop = closest_cop(cx->blk_oldcop, OP_SIBLING(cx->blk_oldcop),
 		       cx->blk_sub.retop, TRUE);
     if (!lcop)
 	lcop = cx->blk_oldcop;
@@ -2701,7 +2701,7 @@ S_dofindlabel(pTHX_ OP *o, const char *label, STRLEN len, U32 flags, OP **opstac
     if (o->op_flags & OPf_KIDS) {
 	OP *kid;
 	/* First try all the kids at this level, since that's likeliest. */
-	for (kid = cUNOPo->op_first; kid; kid = kid->op_sibling) {
+	for (kid = cUNOPo->op_first; kid; kid = OP_SIBLING(kid)) {
 	    if (kid->op_type == OP_NEXTSTATE || kid->op_type == OP_DBSTATE) {
                 STRLEN kid_label_len;
                 U32 kid_label_flags;
@@ -2721,7 +2721,7 @@ S_dofindlabel(pTHX_ OP *o, const char *label, STRLEN len, U32 flags, OP **opstac
 		    return kid;
 	    }
 	}
-	for (kid = cUNOPo->op_first; kid; kid = kid->op_sibling) {
+	for (kid = cUNOPo->op_first; kid; kid = OP_SIBLING(kid)) {
 	    if (kid == PL_lastgotoprobe)
 		continue;
 	    if (kid->op_type == OP_NEXTSTATE || kid->op_type == OP_DBSTATE) {
@@ -3007,13 +3007,13 @@ PP(pp_goto) /* also pp_dump */
 	    case CXt_LOOP_PLAIN:
 	    case CXt_GIVEN:
 	    case CXt_WHEN:
-		gotoprobe = cx->blk_oldcop->op_sibling;
+		gotoprobe = OP_SIBLING(cx->blk_oldcop);
 		break;
 	    case CXt_SUBST:
 		continue;
 	    case CXt_BLOCK:
 		if (ix) {
-		    gotoprobe = cx->blk_oldcop->op_sibling;
+		    gotoprobe = OP_SIBLING(cx->blk_oldcop);
 		    in_block = TRUE;
 		} else
 		    gotoprobe = PL_main_root;
@@ -3039,10 +3039,10 @@ PP(pp_goto) /* also pp_dump */
 				    enterops, enterops + GOTO_DEPTH);
 		if (retop)
 		    break;
-		if (gotoprobe->op_sibling &&
-			gotoprobe->op_sibling->op_type == OP_UNSTACK &&
-			gotoprobe->op_sibling->op_sibling) {
-		    retop = dofindlabel(gotoprobe->op_sibling->op_sibling,
+		if (OP_HAS_SIBLING(gotoprobe) &&
+			OP_SIBLING(gotoprobe)->op_type == OP_UNSTACK &&
+			OP_HAS_SIBLING(OP_SIBLING(gotoprobe))) {
+		    retop = dofindlabel(OP_SIBLING(OP_SIBLING(gotoprobe)),
 					label, label_len, label_flags, enterops,
 					enterops + GOTO_DEPTH);
 		    if (retop)