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

2 files changed, 21 insertions, 0 deletions

diff --git a/lldb/test/python_api/value/linked_list/TestValueAPILinkedList.py b/lldb/test/python_api/value/linked_list/TestValueAPILinkedList.py
index f07ed1b1de2..2d820cbfe09 100644
--- a/lldb/test/python_api/value/linked_list/TestValueAPILinkedList.py
+++ b/lldb/test/python_api/value/linked_list/TestValueAPILinkedList.py
@@ -127,6 +127,20 @@ class ValueAsLinkedListTestCase(TestBase):
 
         self.assertTrue(len(list) == 0)
 
+        # Get variable 'task_evil'.
+        task_evil = frame0.FindVariable('task_evil')
+        self.assertTrue(task_evil, VALID_VARIABLE)
+        self.DebugSBValue(task_evil)
+
+        list = []
+        # There 3 iterable items from task_evil.linked_list_iter(). :-)
+        for t in task_evil.linked_list_iter('next'):
+            if self.TraceOn():
+                print cvf.format(t)
+            list.append(int(t.GetChildMemberWithName("id").GetValue()))
+
+        self.assertTrue(len(list) == 3)
+
 if __name__ == '__main__':
     import atexit
     lldb.SBDebugger.Initialize()
diff --git a/lldb/test/python_api/value/linked_list/main.cpp b/lldb/test/python_api/value/linked_list/main.cpp
index de812178fdd..50517f48774 100644
--- a/lldb/test/python_api/value/linked_list/main.cpp
+++ b/lldb/test/python_api/value/linked_list/main.cpp
@@ -45,5 +45,12 @@ int main (int argc, char const *argv[])
     // This corresponds to an empty task list.
     Task *empty_task_head = NULL;
 
+    Task *task_evil = new Task(1, NULL);
+    Task *task_2 = new Task(2, NULL);
+    Task *task_3 = new Task(3, NULL);
+    task_evil->next = task_2;
+    task_2->next = task_3;
+    task_3->next = task_evil; // In order to cause inifinite loop. :-)
+
     return 0; // Break at this line
 }