Index: Lib/inspect.py
===================================================================
--- Lib/inspect.py	(revision 81388)
+++ Lib/inspect.py	(working copy)
@@ -437,7 +437,9 @@
     if info: return info[0]
 
 def getsourcefile(object):
-    """Return the Python source file an object was defined in, if it exists."""
+    """Return the filename that can be used to locate an object's source.
+    Return None if no way can be identified to get the source.
+    """
     filename = getfile(object)
     if filename[-4:].lower() in ('.pyc', '.pyo'):
         filename = filename[:-4] + '.py'
@@ -450,6 +452,9 @@
     # only return a non-existent filename if the module has a PEP 302 loader
     if hasattr(getmodule(object, filename), '__loader__'):
         return filename
+    # or it is in the linecache
+    if filename in linecache.cache:
+        return filename
 
 def getabsfile(object, _filename=None):
     """Return an absolute path to the source or compiled file for an object.
Index: Lib/test/test_inspect.py
===================================================================
--- Lib/test/test_inspect.py	(revision 81388)
+++ Lib/test/test_inspect.py	(working copy)
@@ -3,6 +3,7 @@
 import types
 import unittest
 import inspect
+import linecache
 import datetime
 import collections
 from os.path import normcase
@@ -275,6 +276,11 @@
     def test_getsourcefile(self):
         self.assertEqual(normcase(inspect.getsourcefile(mod.spam)), modfile)
         self.assertEqual(normcase(inspect.getsourcefile(git.abuse)), modfile)
+        fn = "_non_existing_filename_used_for_sourcefile_test.py"
+        co = compile("None", fn, "exec")
+        self.assertEqual(normcase(inspect.getsourcefile(co)), None)
+        linecache.cache[co.co_filename] = (1, None, "None", co.co_filename)
+        self.assertEqual(normcase(inspect.getsourcefile(co)), fn)
 
     def test_getfile(self):
         self.assertEqual(inspect.getfile(mod.StupidGit), mod.__file__)
@@ -373,6 +379,15 @@
         self.assertRaises(IOError, inspect.getsource, unicodedata)
         self.assertRaises(IOError, inspect.findsource, unicodedata)
 
+    def test_findsource_code_in_linecache(self):
+        lines = ["x=1"]
+        co = compile(lines[0], "_dynamically_created_file", "exec")
+        self.assertRaises(IOError, inspect.findsource, co)
+        self.assertRaises(IOError, inspect.getsource, co)
+        linecache.cache[co.co_filename] = (1, None, lines, co.co_filename)
+        self.assertEquals(inspect.findsource(co), (lines,0))
+        self.assertEquals(inspect.getsource(co), lines[0])
+
 # Helper for testing classify_class_attrs.
 def attrs_wo_objs(cls):
     return [t[:3] for t in inspect.classify_class_attrs(cls)]