Issue #8847: Merge with 3.2

Lib/test/test_list.py

@@ -98,6 +98,14 @@ class ListTest(list_tests.CommonTest):
         d = pickle.dumps(it)
         self.assertEqual(self.type2test(it), self.type2test(reversed(data))[1:])
 
+    def test_no_comdat_folding(self):
+        # Issue 8847: In the PGO build, the MSVC linker's COMDAT folding
+        # optimization causes failures in code that relies on distinct
+        # function addresses.
+        class L(list): pass
+        with self.assertRaises(TypeError):
+            (3,) + L([1,2])
+
 def test_main(verbose=None):
     support.run_unittest(ListTest)
 

Lib/test/test_tuple.py

@@ -193,6 +193,14 @@ class TupleTest(seq_tests.CommonTest):
         d = pickle.dumps(it)
         self.assertEqual(self.type2test(it), self.type2test(reversed(data))[1:])
 
+    def test_no_comdat_folding(self):
+        # Issue 8847: In the PGO build, the MSVC linker's COMDAT folding
+        # optimization causes failures in code that relies on distinct
+        # function addresses.
+        class T(tuple): pass
+        with self.assertRaises(TypeError):
+            [3,] + T((1,2))
+
 def test_main():
     support.run_unittest(TupleTest)
 

Misc/NEWS

@@ -276,6 +276,8 @@ Tests
 Build
 -----
 
+- Issue #8847: Disable COMDAT folding in Windows PGO builds.
+
 - Issue #14018: Fix OS X Tcl/Tk framework checking when using OS X SDKs.
 
 - Issue #15431: Add _freeze_importlib project to regenerate importlib.h

PC/VS9.0/pginstrument.vsprops

@@ -22,7 +22,7 @@
 	<Tool
 		Name="VCLinkerTool"
 		OptimizeReferences="2"
-		EnableCOMDATFolding="2"
+		EnableCOMDATFolding="1"
 		LinkTimeCodeGeneration="2"
 		ProfileGuidedDatabase="$(SolutionDir)$(PlatformName)-pgi\$(TargetName).pgd"
 		ImportLibrary="$(OutDirPGI)\$(TargetName).lib"