vm_eval.c: rb_check_funcall_default

* vm_eval.c (rb_check_funcall_default): split from
  rb_check_funcall to return the given fallback value.
* object.c (rb_obj_dig): use rb_check_funcall_default so that tail
  call optimization will be possible.  [Feature ruby#11643]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52505 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,11 @@
+Mon Nov  9 21:48:17 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_eval.c (rb_check_funcall_default): split from
+	  rb_check_funcall to return the given fallback value.
+
+	* object.c (rb_obj_dig): use rb_check_funcall_default so that tail
+	  call optimization will be possible.  [Feature #11643]
+
 Mon Nov  9 21:27:23 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* array.c (rb_ary_dig): new method Array#dig.

internal.h

@@ -1218,6 +1218,7 @@ VALUE rb_check_block_call(VALUE, ID, int, const VALUE *, rb_block_call_func_t, V
 typedef void rb_check_funcall_hook(int, VALUE, ID, int, const VALUE *, VALUE);
 VALUE rb_check_funcall_with_hook(VALUE recv, ID mid, int argc, const VALUE *argv,
 				 rb_check_funcall_hook *hook, VALUE arg);
+VALUE rb_check_funcall_default(VALUE, ID, int, const VALUE *, VALUE);
 VALUE rb_catch_protect(VALUE t, rb_block_call_func *func, VALUE data, int *stateptr);
 VALUE rb_yield_1(VALUE val);
 

object.c

@@ -3183,9 +3183,7 @@ rb_obj_dig(int argc, VALUE *argv, VALUE obj, VALUE notfound)
 		}
 	    }
 	}
-	obj = rb_check_funcall(obj, id_dig, argc, argv);
-	if (obj == Qundef) return notfound;
-	break;
+	return rb_check_funcall_default(obj, id_dig, argc, argv, notfound);
     }
     return obj;
 }

vm_eval.c

@@ -410,18 +410,18 @@ check_funcall_callable(rb_thread_t *th, const rb_callable_method_entry_t *me)
 }
 
 static VALUE
-check_funcall_missing(rb_thread_t *th, VALUE klass, VALUE recv, ID mid, int argc, const VALUE *argv, int respond)
+check_funcall_missing(rb_thread_t *th, VALUE klass, VALUE recv, ID mid, int argc, const VALUE *argv, int respond, VALUE def)
 {
     struct rescue_funcall_args args;
     const rb_method_entry_t *me;
     VALUE ret = Qundef;
 
     ret = basic_obj_respond_to_missing(th, klass, recv,
 				       ID2SYM(mid), PRIV);
-    if (!RTEST(ret)) return Qundef;
+    if (!RTEST(ret)) return def;
     args.respond = respond > 0;
     args.respond_to_missing = (ret != Qundef);
-    ret = Qundef;
+    ret = def;
     me = method_entry_get(klass, idMethodMissing, &args.defined_class);
     if (me && !METHOD_ENTRY_BASIC(me)) {
 	VALUE argbuf, *new_args = ALLOCV_N(VALUE, argbuf, argc+1);
@@ -445,18 +445,25 @@ check_funcall_missing(rb_thread_t *th, VALUE klass, VALUE recv, ID mid, int argc
 
 VALUE
 rb_check_funcall(VALUE recv, ID mid, int argc, const VALUE *argv)
+{
+    return rb_check_funcall_default(recv, mid, argc, argv, Qundef);
+}
+
+VALUE
+rb_check_funcall_default(VALUE recv, ID mid, int argc, const VALUE *argv, VALUE def)
 {
     VALUE klass = CLASS_OF(recv);
     const rb_callable_method_entry_t *me;
     rb_thread_t *th = GET_THREAD();
     int respond = check_funcall_respond_to(th, klass, recv, mid);
 
     if (!respond)
-	return Qundef;
+	return def;
 
     me = rb_search_method_entry(recv, mid);
     if (!check_funcall_callable(th, me)) {
-	return check_funcall_missing(th, klass, recv, mid, argc, argv, respond);
+	return check_funcall_missing(th, klass, recv, mid, argc, argv,
+				     respond, def);
     }
     stack_check();
     return vm_call0(th, recv, mid, argc, argv, me);
@@ -477,7 +484,8 @@ rb_check_funcall_with_hook(VALUE recv, ID mid, int argc, const VALUE *argv,
     me = rb_search_method_entry(recv, mid);
     if (!check_funcall_callable(th, me)) {
 	(*hook)(FALSE, recv, mid, argc, argv, arg);
-	return check_funcall_missing(th, klass, recv, mid, argc, argv, respond);
+	return check_funcall_missing(th, klass, recv, mid, argc, argv,
+				     respond, Qundef);
     }
     stack_check();
     (*hook)(TRUE, recv, mid, argc, argv, arg);