[dynamo] misc fixes for inspect (#146283)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/146283
Approved by: https://github.com/jansel
ghstack dependencies: #146075

test/dynamo/test_repros.py

@@ -6635,6 +6635,19 @@ class ReproTestsDevice(torch._dynamo.test_case.TestCase):
         mem_after = torch.cuda.memory_allocated()
         self.assertEqual(mem_before, mem_after)
 
+    def test_udf_class_source(self):
+        class Foo:
+            pass
+
+        def fn(x):
+            foo = Foo()
+            bar = type(foo)()  # noqa: F841
+            return torch.cos(x)
+
+        opt_fn = torch.compile(fn, backend="eager", fullgraph=True)
+        x = torch.randn(4)
+        self.assertEqual(fn(x), opt_fn(x))
+
     @requires_cuda
     def test_sdpa_dynamic_shapes(self, device):
         def f(x, s0, s1, s2):

torch/_dynamo/variables/builtin.py

@@ -1942,6 +1942,12 @@ class BuiltinVariable(VariableTracker):
             ) from None
 
         source = obj.source and TypeSource(obj.source)
+        if (
+            source is None
+            and isinstance(obj, variables.UserDefinedObjectVariable)
+            and obj.cls_source
+        ):
+            source = obj.cls_source
         if py_type is torch.Tensor:
             # In some cases torch isn't available in globals
             name = tx.output.install_global_by_id("", torch)
@@ -2004,6 +2010,8 @@ class BuiltinVariable(VariableTracker):
             return tensor_variable.call_id(tx)
         elif istype(args[0], variables.UserFunctionVariable):
             return variables.ConstantVariable.create(id(args[0].fn))
+        elif istype(args[0], variables.SkipFunctionVariable):
+            return variables.ConstantVariable.create(id(args[0].value))
         else:
             unimplemented(f"call_id with args {args}")
 

torch/_dynamo/variables/functions.py

@@ -734,6 +734,13 @@ class SkipFunctionVariable(VariableTracker):
     ) -> "VariableTracker":
         if inspect.getattr_static(self.value, "_torchdynamo_disable", False):
             unimplemented(f"call torch._dynamo.disable() wrapped function {self.value}")
+        elif isinstance(self.value, types.WrapperDescriptorType):
+            msg = (
+                f"Graph break due to unsupported wrapper descriptor {self.value}. "
+                f"Please file an issue on GitHub "
+                f"so the PyTorch team can add support for it. "
+            )
+            torch._dynamo.utils.warn_once(msg)
         else:
             try:
                 path = inspect.getfile(self.value)