Add rb_block_call2, a flexible variant of rb_block_call

This function accepts flags:

RB_NO_KEYWORDS, RB_PASS_KEYWORDS, RB_PASS_CALLED_KEYWORDS:
Works as the same as rb_block_call_kw.

RB_BLOCK_NO_USE_PACKED_ARGS:
The given block ("bl_proc") does not use "yielded_arg" of rb_block_call_func_t.
Instead, the block accesses the yielded arguments via "argc" and "argv".
This flag allows the called method to yield arguments without allocating an Array.

include/ruby/internal/scan_args.h

@@ -75,7 +75,7 @@
  * Pass keywords if current method is called with keywords, useful for argument
  * delegation
  */
-#define RB_PASS_CALLED_KEYWORDS rb_keyword_given_p()
+#define RB_PASS_CALLED_KEYWORDS !!rb_keyword_given_p()
 
 /** @} */
 

internal/imemo.h

@@ -87,6 +87,7 @@ struct vm_ifunc {
     const void *data;
     struct vm_ifunc_argc argc;
 };
+#define IFUNC_YIELD_OPTIMIZABLE IMEMO_FL_USER0
 
 struct rb_imemo_tmpbuf_struct {
     VALUE flags;

internal/vm.h

@@ -77,6 +77,8 @@ VALUE rb_lambda_call(VALUE obj, ID mid, int argc, const VALUE *argv,
                      rb_block_call_func_t bl_proc, int min_argc, int max_argc,
                      VALUE data2);
 void rb_check_stack_overflow(void);
+#define RB_BLOCK_NO_USE_PACKED_ARGS 2
+VALUE rb_block_call2(VALUE obj, ID mid, int argc, const VALUE *argv, rb_block_call_func_t bl_proc, VALUE data2, long flags);
 
 #if USE_YJIT
 /* vm_exec.c */

proc.c

@@ -1159,6 +1159,12 @@ rb_block_pair_yield_optimizable(void)
             return min > 1;
         }
 
+      case block_handler_type_ifunc:
+        {
+            const struct vm_ifunc *ifunc = block.as.captured.code.ifunc;
+            if (ifunc->flags & IFUNC_YIELD_OPTIMIZABLE) return 1;
+        }
+
       default:
         return min > 1;
     }

vm_eval.c

@@ -1558,6 +1558,37 @@ rb_block_call_kw(VALUE obj, ID mid, int argc, const VALUE * argv,
     return rb_iterate_internal(iterate_method, (VALUE)&arg, bl_proc, data2);
 }
 
+/*
+ * A flexible variant of rb_block_call and rb_block_call_kw.
+ * This function accepts flags:
+ *
+ *   RB_NO_KEYWORDS, RB_PASS_KEYWORDS, RB_PASS_CALLED_KEYWORDS:
+ *   Works as the same as rb_block_call_kw.
+ *
+ *   RB_BLOCK_NO_USE_PACKED_ARGS:
+ *   The given block ("bl_proc") does not use "yielded_arg" of rb_block_call_func_t.
+ *   Instead, the block accesses the yielded arguments via "argc" and "argv".
+ *   This flag allows the called method to yield arguments without allocating an Array.
+ */
+VALUE
+rb_block_call2(VALUE obj, ID mid, int argc, const VALUE *argv,
+               rb_block_call_func_t bl_proc, VALUE data2, long flags)
+{
+    struct iter_method_arg arg;
+
+    arg.obj = obj;
+    arg.mid = mid;
+    arg.argc = argc;
+    arg.argv = argv;
+    arg.kw_splat = flags & 1;
+
+    struct vm_ifunc *ifunc = rb_vm_ifunc_proc_new(bl_proc, (void *)data2);
+    if (flags & RB_BLOCK_NO_USE_PACKED_ARGS)
+        ifunc->flags |= IFUNC_YIELD_OPTIMIZABLE;
+
+    return rb_iterate0(iterate_method, (VALUE)&arg, ifunc, GET_EC());
+}
+
 VALUE
 rb_lambda_call(VALUE obj, ID mid, int argc, const VALUE *argv,
                rb_block_call_func_t bl_proc, int min_argc, int max_argc,