Fix invalid assertion in vm_loop. (#1561)

Because of the fallthrough case the value of 3 is also allowed in the default case.

Fixes #1555.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/vm/vm.c

@@ -808,7 +808,8 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
           }
           default:
           {
-            JERRY_ASSERT (CBC_BRANCH_OFFSET_LENGTH (opcode) == 2);
+            JERRY_ASSERT (CBC_BRANCH_OFFSET_LENGTH (opcode) == 2
+                          || CBC_BRANCH_OFFSET_LENGTH (opcode) == 3);
 
             branch_offset <<= 8;
             branch_offset |= *(byte_code_p++);

tests/jerry/regression-test-issue-1555.js

@@ -0,0 +1,21 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var src = "var a = 0; while(a) { switch(a) {";
+/* The += operation has a longer opcode. */
+for (var i = 0; i < 4000; i++)
+    src += "case " + i + ": a += a += a; break; ";
+src += "} }";
+
+eval(src);