# Copyright 2019 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
def make_copy(obj, memo=None):
"""
Creates a copy of the given object, which should be an IR or part of IR.
The copy is created basically as a deep copy of the object, but |make_copy|
method is used to create a (part of) copy if the object (or part of it) has
the method. |memo| argument behaves as the same as |deepcopy|.
"""
if memo is None:
memo = dict()
if obj is None or isinstance(obj, (bool, int, float, complex, str)):
# Do not make a copy if the object is of an immutable primitive type
# (or its subclass).
#
# Memoization is tricky in case that both of Identifier('x') and
# Component('x') exist. We could memoize them as
# |memo[(type(obj), obj)] = copy|, though.
return obj
if hasattr(obj, 'make_copy'):
return obj.make_copy(memo=memo)
memoizable = obj.__hash__ is not None
if memoizable:
copy = memo.get(obj, None)
if copy is not None:
return copy
def memoize(copy):
if memoizable:
memo[obj] = copy
return copy
cls = type(obj)
if isinstance(obj, (list, tuple, set, frozenset)):
return memoize(cls(map(lambda x: make_copy(x, memo), obj)))
if isinstance(obj, dict):
return memoize(
cls([(make_copy(key, memo), make_copy(value, memo))
for key, value in obj.items()]))
if hasattr(obj, '__dict__'):
copy = memoize(cls.__new__(cls))
for name, value in obj.__dict__.items():
setattr(copy, name, make_copy(value, memo))
return copy
assert False, 'Unsupported type of object: {}'.format(cls)
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