symbol.c (rb_id2str): eliminate branch to set class

Since the fstring table encompasses all strings in the
symbol table, we may reuse the fstring table walk to set
the class and eliminate the branch in rb_id2str.

* string.c (Init_String): use rb_cString immediately after definition
* symbol.c (rb_id2str): eliminate branch to set class

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57521 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

string.c

@@ -10036,6 +10036,8 @@ Init_String(void)
 #define rb_intern(str) rb_intern_const(str)
 
     rb_cString  = rb_define_class("String", rb_cObject);
+    assert(rb_vm_fstring_table());
+    st_foreach(rb_vm_fstring_table(), fstring_set_class_i, rb_cString);
     rb_include_module(rb_cString, rb_mComparable);
     rb_define_alloc_func(rb_cString, empty_str_alloc);
     rb_define_singleton_method(rb_cString, "try_convert", rb_str_s_try_convert, 1);
@@ -10215,7 +10217,4 @@ Init_String(void)
     rb_define_method(rb_cSymbol, "swapcase", sym_swapcase, -1);
 
     rb_define_method(rb_cSymbol, "encoding", sym_encoding, 0);
-
-    assert(rb_vm_fstring_table());
-    st_foreach(rb_vm_fstring_table(), fstring_set_class_i, rb_cString);
 }

symbol.c

@@ -744,15 +744,7 @@ rb_sym2str(VALUE sym)
 VALUE
 rb_id2str(ID id)
 {
-    VALUE str;
-
-    if ((str = lookup_id_str(id)) != 0) {
-        if (RBASIC(str)->klass == 0)
-            RBASIC_SET_CLASS_RAW(str, rb_cString);
-	return str;
-    }
-
-    return 0;
+    return lookup_id_str(id);
 }
 
 const char *