[pytorch][codegen] remove dead code in gen_variable_type.py (pytorch#…

…47975)

Summary: Pull Request resolved: pytorch#47975

Test Plan: Imported from OSS

Reviewed By: ezyang

Differential Revision: D24976274

Pulled By: ljk53

fbshipit-source-id: 8542471ee30f26592aad949fc17eef87a47df024

tools/autograd/gen_variable_type.py

@@ -263,36 +263,6 @@
 #endif
 """)
 
-FACTORY_FUNCTION_NAMES = None
-
-# TODO The maybe_unwrap_optional_tensors is only needed because our at::native::xxx functions
-# still take "Tensor" instead of "optional<Tensor>", so we need CPUType, TypeDefault, ...
-# to do the same. Once at::native::xxx are converted, we can remove use_optional_tensor
-# and use the use_optional_tensor=True behavior always.
-def maybe_unwrap_optional_tensors(option, formals, args):
-    assert len(formals) == len(args), \
-        "Assert we didn't screw up with method_args removing self but forgetting to remove it from formals"
-    if option['use_c10_dispatcher'] in ['full', 'hacky_wrapper_for_legacy_signatures']:
-        def maybe_unwrap_optional_tensor(formal, arg):
-            if formal['dynamic_type'] == 'Tensor' and formal['is_nullable']:
-                return "{}.has_value() ? *{} : at::Tensor()".format(arg, arg)
-            else:
-                return arg
-        return [maybe_unwrap_optional_tensor(formal, arg) for (formal, arg) in zip(formals, args)]
-    else:
-        assert option['use_c10_dispatcher'] == 'with_codegenerated_unboxing_wrapper'
-        return args
-
-
-def find_factory_functions(declarations):
-    global FACTORY_FUNCTION_NAMES
-    FACTORY_FUNCTION_NAMES = set()
-
-    for declaration in declarations:
-        if declaration['is_factory_method']:
-            FACTORY_FUNCTION_NAMES.add(declaration['api_name'])
-
-
 # Methods shared by TraceType and VariableType to handle return variable declaration, tie and tuple.
 def format_return_variables(declaration):
     name = declaration['name']
@@ -344,9 +314,6 @@ def gen_variable_type(out, aten_declarations, template_path):
     compute the output. The grad_fn is attached to differentiable functions.
     """
 
-    # WARNING: this function call modifies global mutable state
-    find_factory_functions(aten_declarations)
-
     aten_declarations = list(sorted(aten_declarations, key=lambda decl: decl['name']))
 
     gen_variable_type_shard(out, aten_declarations, template_path, None, True)