1 files changed, 20 insertions, 4 deletions
diff --git a/src/engine/SCons/Debug.py b/src/engine/SCons/Debug.py
index 9974039..9e520ff 100644
--- a/src/engine/SCons/Debug.py
+++ b/src/engine/SCons/Debug.py
@@ -1,7 +1,10 @@
 """SCons.Debug
 
 Code for debugging SCons internal things.  Shouldn't be
-needed by most users.
+needed by most users. Quick shortcuts:
+
+from SCons.Debug import caller_trace
+caller_trace()
 
 """
 
@@ -34,6 +37,7 @@ import os
 import sys
 import time
 import weakref
+import inspect
 
 # Global variable that gets set to 'True' by the Main script,
 # when the creation of class instances should get tracked.
@@ -46,7 +50,12 @@ def logInstanceCreation(instance, name=None):
         name = instance.__class__.__name__
     if name not in tracked_classes:
         tracked_classes[name] = []
-    tracked_classes[name].append(weakref.ref(instance))
+    if hasattr(instance, '__dict__'):
+        tracked_classes[name].append(weakref.ref(instance))
+    else:
+        # weakref doesn't seem to work when the instance
+        # contains only slots...
+        tracked_classes[name].append(instance)
 
 def string_to_classes(s):
     if s == '*':
@@ -66,7 +75,10 @@ def listLoggedInstances(classes, file=sys.stdout):
     for classname in string_to_classes(classes):
         file.write('\n%s:\n' % classname)
         for ref in tracked_classes[classname]:
-            obj = ref()
+            if inspect.isclass(ref):
+                obj = ref()
+            else:
+                obj = ref
             if obj is not None:
                 file.write('    %s\n' % repr(obj))
 
@@ -128,8 +140,12 @@ def caller_stack():
 caller_bases = {}
 caller_dicts = {}
 
-# trace a caller's stack
 def caller_trace(back=0):
+    """
+    Trace caller stack and save info into global dicts, which
+    are printed automatically at the end of SCons execution.
+    """
+    global caller_bases, caller_dicts
     import traceback
     tb = traceback.extract_stack(limit=3+back)
     tb.reverse()