--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/builtins/SLAssertFalseBuiltin.java	Mon Sep 01 20:08:18 2014 +0200
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.sl.builtins;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.dsl.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.source.*;
+import com.oracle.truffle.sl.runtime.*;
+
+/**
+ * Asserts a given value to be <code>false</code> and throws an {@link AssertionError} if the value
+ * was <code>true</code>.
+ */
+@NodeInfo(shortName = "assertFalse")
+public abstract class SLAssertFalseBuiltin extends SLBuiltinNode {
+
+    public SLAssertFalseBuiltin() {
+        super(new NullSourceSection("SL builtin", "assertFalse"));
+    }
+
+    @Specialization
+    public boolean doAssert(boolean value, String message) {
+        if (value) {
+            CompilerDirectives.transferToInterpreter();
+            if (message == null) {
+                throw new AssertionError();
+            } else {
+                throw new AssertionError(message);
+            }
+        }
+        return value;
+    }
+
+    @Specialization
+    public boolean doAssertNull(boolean value, @SuppressWarnings("unused") SLNull message) {
+        return doAssert(value, null);
+    }
+
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/builtins/SLAssertTrueBuiltin.java	Mon Sep 01 20:08:18 2014 +0200
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.sl.builtins;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.dsl.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.source.*;
+import com.oracle.truffle.sl.runtime.*;
+
+/**
+ * Asserts a given value to be <code>true</code> and throws an {@link AssertionError} if the value
+ * was <code>false</code>.
+ */
+@NodeInfo(shortName = "assertTrue")
+public abstract class SLAssertTrueBuiltin extends SLBuiltinNode {
+
+    public SLAssertTrueBuiltin() {
+        super(new NullSourceSection("SL builtin", "assertTrue"));
+    }
+
+    @Specialization
+    public boolean doAssert(boolean value, String message) {
+        if (!value) {
+            CompilerDirectives.transferToInterpreter();
+            if (message == null) {
+                throw new AssertionError();
+            } else {
+                throw new AssertionError(message);
+            }
+        }
+        return value;
+    }
+
+    @Specialization
+    public boolean doAssertNull(boolean value, @SuppressWarnings("unused") SLNull message) {
+        return doAssert(value, null);
+    }
+
+}

--- a/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/runtime/SLContext.java	Mon Sep 01 16:46:59 2014 +0200
+++ b/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/runtime/SLContext.java	Mon Sep 01 20:08:18 2014 +0200
@@ -109,9 +109,11 @@
         installBuiltin(SLDefineFunctionBuiltinFactory.getInstance());
         installBuiltin(SLStackTraceBuiltinFactory.getInstance());
         installBuiltin(SLHelloEqualsWorldBuiltinFactory.getInstance());
+        installBuiltin(SLAssertTrueBuiltinFactory.getInstance());
+        installBuiltin(SLAssertFalseBuiltinFactory.getInstance());
     }
 
-    private void installBuiltin(NodeFactory<? extends SLBuiltinNode> factory) {
+    public void installBuiltin(NodeFactory<? extends SLBuiltinNode> factory) {
         /*
          * The builtin node factory is a class that is automatically generated by the Truffle DSL.
          * The signature returned by the factory reflects the signature of the @Specialization