Add logic to SBValue.linked_list_iter() to detect infinite loop and to bail out early.

Add code to test case to create an evil linked list with:

    task_evil -> task_2 -> task_3 -> task_evil ...

and to check that the linked list iterator only iterates 3 times.

llvm-svn: 137291

lldb/scripts/Python/modify-python-lldb.py

@@ -112,6 +112,8 @@ linked_list_iter_def = '''
         end-of-list test function which takes an SBValue for an item and returns
         True if EOL is reached and False if not.
 
+        linked_list_iter() also detects infinite loop and bails out early.
+
         The end_of_list_test arg, if omitted, defaults to the __eol_test__
         function above.
 
@@ -130,8 +132,10 @@ linked_list_iter_def = '''
         if end_of_list_test(self):
             return
         item = self
+        visited = set()
         try:
-            while not end_of_list_test(item):
+            while not end_of_list_test(item) and not item.GetValueAsUnsigned() in visited:
+                visited.add(item.GetValueAsUnsigned())
                 yield item
                 # Prepare for the next iteration.
                 item = item.GetChildMemberWithName(next_item_name)