eval.c: no method calls at stack overflow

* eval.c (setup_exception): get rid of method calls before raising
  stack overflow, not to cause stack overflow again.
* defs/id.def: add IDs for backtraces.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46593 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Sat Jun 28 13:58:19 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* eval.c (setup_exception): get rid of method calls before raising
+	  stack overflow, not to cause stack overflow again.
+
+	* defs/id.def: add IDs for backtraces.
+
 Sat Jun 28 04:08:22 2014  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/uri/mailto.rb: update to latest specs, RFC 6068 and HTML5.

defs/id.def

@@ -36,6 +36,8 @@ firstline, predefined = __LINE__+1, %[\
   to_a
   to_s
   to_i
+  bt
+  bt_locations
 
   _                                                     UScore
   "/*NULL*/"                                            NULL

eval.c

@@ -469,7 +469,6 @@ sysstack_error_p(VALUE exc)
 static void
 setup_exception(rb_thread_t *th, int tag, volatile VALUE mesg, VALUE cause)
 {
-    VALUE at;
     VALUE e;
     const char *file = 0;
     volatile int line = 0;
@@ -492,24 +491,22 @@ setup_exception(rb_thread_t *th, int tag, volatile VALUE mesg, VALUE cause)
     file = rb_sourcefile();
     if (file) line = rb_sourceline();
     if (file && !NIL_P(mesg)) {
-	if (mesg == sysstack_error) {
-	    /* machine stack overflow, reduce too long backtrace */
-	    ID func = rb_frame_this_func();
-	    at = rb_enc_sprintf(rb_usascii_encoding(), "%s:%d", file, line);
-	    if (func) {
-		VALUE name = rb_id2str(func);
-		if (name) rb_str_catf(at, ":in `%"PRIsVALUE"'", name);
+	VALUE at;
+	if (sysstack_error_p(mesg)) {
+	    at = rb_vm_backtrace_object();
+	    if (mesg == sysstack_error) {
+		VALUE ruby_vm_sysstack_error_copy(void);
+		mesg = ruby_vm_sysstack_error_copy();
 	    }
-	    at = rb_ary_new3(1, at);
-	    mesg = rb_obj_dup(mesg);
-	    rb_iv_set(mesg, "bt", at);
+	    rb_ivar_set(mesg, idBt, at);
+	    rb_ivar_set(mesg, idBt_locations, at);
 	}
-	else if (sysstack_error_p(mesg) || NIL_P(at = get_backtrace(mesg))) {
+	else if (NIL_P(get_backtrace(mesg))) {
 	    at = rb_vm_backtrace_object();
 	    if (OBJ_FROZEN(mesg)) {
 		mesg = rb_obj_dup(mesg);
 	    }
-	    rb_iv_set(mesg, "bt_locations", at);
+	    rb_ivar_set(mesg, idBt_locations, at);
 	    set_backtrace(mesg, at);
 	}
     }

test/ruby/test_exception.rb

@@ -529,8 +529,10 @@ end.join
   end
 
   def test_stackoverflow
-    e = assert_raise(SystemStackError){m}
-    assert_operator(e.backtrace.size, :>, 10)
+    feature6216 = '[ruby-core:43794] [Feature #6216]'
+    e = assert_raise(SystemStackError, feature6216) {m}
+    level = e.backtrace.size
+    assert_operator(level, :>, 10, feature6216)
   end
 
   def test_machine_stackoverflow

vm_insnhelper.c

@@ -24,12 +24,18 @@
 
 static rb_control_frame_t *vm_get_ruby_level_caller_cfp(rb_thread_t *th, rb_control_frame_t *cfp);
 
-static void
-vm_stackoverflow(void)
+VALUE
+ruby_vm_sysstack_error_copy(void)
 {
     VALUE e = rb_obj_alloc(rb_eSysStackError);
     rb_obj_copy_ivar(e, sysstack_error);
-    rb_exc_raise(e);
+    return e;
+}
+
+static void
+vm_stackoverflow(void)
+{
+    rb_exc_raise(ruby_vm_sysstack_error_copy());
 }
 
 static inline rb_control_frame_t *