--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.ruby.runtime/src/com/oracle/truffle/ruby/runtime/debug/RubyBreakBeforeLineProbe.java	Wed Jan 08 14:03:36 2014 -0800
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved. This
+ * code is released under a tri EPL/GPL/LGPL license. You can use it,
+ * redistribute it and/or modify it under the terms of the:
+ *
+ * Eclipse Public License version 1.0
+ * GNU General Public License version 2
+ * GNU Lesser General Public License version 2.1
+ */
+package com.oracle.truffle.ruby.runtime.debug;
+
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.source.*;
+import com.oracle.truffle.ruby.runtime.*;
+
+/**
+ * A probe for halting execution at a line before a child execution method.
+ */
+public final class RubyBreakBeforeLineProbe extends RubyLineProbe {
+
+    /**
+     * Creates a probe that will cause a halt just before child execution starts; a {@code oneShot}
+     * probe will remove itself the first time it halts.
+     */
+    public RubyBreakBeforeLineProbe(RubyContext context, SourceLineLocation location, boolean oneShot) {
+        super(context, location, oneShot);
+    }
+
+    @Override
+    public void enter(Node astNode, VirtualFrame frame) {
+
+        if (!isStepping()) {
+            // Ordinary line breakpoints ignored during stepping so no double halts.
+            if (oneShot) {
+                // One-shot breakpoints retire after one activation.
+                context.getDebugManager().retireLineProbe(location, this);
+            }
+            context.getDebugManager().haltedAt(astNode, frame.materialize());
+        }
+    }
+}