316 lines
11 KiB
Python
316 lines
11 KiB
Python
import dis
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import re
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import sys
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from io import StringIO
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import unittest
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def disassemble(func):
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f = StringIO()
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tmp = sys.stdout
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sys.stdout = f
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try:
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dis.dis(func)
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finally:
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sys.stdout = tmp
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result = f.getvalue()
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f.close()
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return result
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def dis_single(line):
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return disassemble(compile(line, '', 'single'))
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class TestTranforms(unittest.TestCase):
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def test_unot(self):
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# UNARY_NOT POP_JUMP_IF_FALSE --> POP_JUMP_IF_TRUE'
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def unot(x):
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if not x == 2:
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del x
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asm = disassemble(unot)
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for elem in ('UNARY_NOT', 'POP_JUMP_IF_FALSE'):
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self.assertNotIn(elem, asm)
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for elem in ('POP_JUMP_IF_TRUE',):
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self.assertIn(elem, asm)
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def test_elim_inversion_of_is_or_in(self):
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for line, elem in (
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('not a is b', '(is not)',),
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('not a in b', '(not in)',),
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('not a is not b', '(is)',),
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('not a not in b', '(in)',),
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):
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asm = dis_single(line)
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self.assertIn(elem, asm)
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def test_global_as_constant(self):
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# LOAD_GLOBAL None/True/False --> LOAD_CONST None/True/False
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def f(x):
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None
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None
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return x
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def g(x):
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True
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return x
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def h(x):
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False
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return x
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for func, name in ((f, 'None'), (g, 'True'), (h, 'False')):
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asm = disassemble(func)
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for elem in ('LOAD_GLOBAL',):
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self.assertNotIn(elem, asm)
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for elem in ('LOAD_CONST', '('+name+')'):
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self.assertIn(elem, asm)
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def f():
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'Adding a docstring made this test fail in Py2.5.0'
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return None
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self.assertIn('LOAD_CONST', disassemble(f))
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self.assertNotIn('LOAD_GLOBAL', disassemble(f))
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def test_while_one(self):
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# Skip over: LOAD_CONST trueconst POP_JUMP_IF_FALSE xx
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def f():
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while 1:
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pass
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return list
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asm = disassemble(f)
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for elem in ('LOAD_CONST', 'POP_JUMP_IF_FALSE'):
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self.assertNotIn(elem, asm)
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for elem in ('JUMP_ABSOLUTE',):
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self.assertIn(elem, asm)
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def test_pack_unpack(self):
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for line, elem in (
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('a, = a,', 'LOAD_CONST',),
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('a, b = a, b', 'ROT_TWO',),
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('a, b, c = a, b, c', 'ROT_THREE',),
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):
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asm = dis_single(line)
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self.assertIn(elem, asm)
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self.assertNotIn('BUILD_TUPLE', asm)
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self.assertNotIn('UNPACK_TUPLE', asm)
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def test_folding_of_tuples_of_constants(self):
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for line, elem in (
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('a = 1,2,3', '((1, 2, 3))'),
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('("a","b","c")', "(('a', 'b', 'c'))"),
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('a,b,c = 1,2,3', '((1, 2, 3))'),
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('(None, 1, None)', '((None, 1, None))'),
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('((1, 2), 3, 4)', '(((1, 2), 3, 4))'),
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):
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asm = dis_single(line)
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self.assertIn(elem, asm)
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self.assertNotIn('BUILD_TUPLE', asm)
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# Long tuples should be folded too.
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asm = dis_single(repr(tuple(range(10000))))
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# One LOAD_CONST for the tuple, one for the None return value
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self.assertEqual(asm.count('LOAD_CONST'), 2)
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self.assertNotIn('BUILD_TUPLE', asm)
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# Bug 1053819: Tuple of constants misidentified when presented with:
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# . . . opcode_with_arg 100 unary_opcode BUILD_TUPLE 1 . . .
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# The following would segfault upon compilation
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def crater():
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(~[
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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],)
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def test_folding_of_lists_of_constants(self):
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for line, elem in (
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# in/not in constants with BUILD_LIST should be folded to a tuple:
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('a in [1,2,3]', '(1, 2, 3)'),
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('a not in ["a","b","c"]', "(('a', 'b', 'c'))"),
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('a in [None, 1, None]', '((None, 1, None))'),
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('a not in [(1, 2), 3, 4]', '(((1, 2), 3, 4))'),
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):
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asm = dis_single(line)
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self.assertIn(elem, asm)
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self.assertNotIn('BUILD_LIST', asm)
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def test_folding_of_sets_of_constants(self):
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for line, elem in (
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# in/not in constants with BUILD_SET should be folded to a frozenset:
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('a in {1,2,3}', frozenset({1, 2, 3})),
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('a not in {"a","b","c"}', frozenset({'a', 'c', 'b'})),
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('a in {None, 1, None}', frozenset({1, None})),
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('a not in {(1, 2), 3, 4}', frozenset({(1, 2), 3, 4})),
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('a in {1, 2, 3, 3, 2, 1}', frozenset({1, 2, 3})),
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):
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asm = dis_single(line)
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self.assertNotIn('BUILD_SET', asm)
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# Verify that the frozenset 'elem' is in the disassembly
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# The ordering of the elements in repr( frozenset ) isn't
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# guaranteed, so we jump through some hoops to ensure that we have
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# the frozenset we expect:
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self.assertIn('frozenset', asm)
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# Extract the frozenset literal from the disassembly:
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m = re.match(r'.*(frozenset\({.*}\)).*', asm, re.DOTALL)
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self.assertTrue(m)
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self.assertEqual(eval(m.group(1)), elem)
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# Ensure that the resulting code actually works:
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def f(a):
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return a in {1, 2, 3}
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def g(a):
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return a not in {1, 2, 3}
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self.assertTrue(f(3))
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self.assertTrue(not f(4))
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self.assertTrue(not g(3))
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self.assertTrue(g(4))
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def test_folding_of_binops_on_constants(self):
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for line, elem in (
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('a = 2+3+4', '(9)'), # chained fold
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('"@"*4', "('@@@@')"), # check string ops
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('a="abc" + "def"', "('abcdef')"), # check string ops
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('a = 3**4', '(81)'), # binary power
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('a = 3*4', '(12)'), # binary multiply
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('a = 13//4', '(3)'), # binary floor divide
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('a = 14%4', '(2)'), # binary modulo
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('a = 2+3', '(5)'), # binary add
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('a = 13-4', '(9)'), # binary subtract
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('a = (12,13)[1]', '(13)'), # binary subscr
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('a = 13 << 2', '(52)'), # binary lshift
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('a = 13 >> 2', '(3)'), # binary rshift
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('a = 13 & 7', '(5)'), # binary and
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('a = 13 ^ 7', '(10)'), # binary xor
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('a = 13 | 7', '(15)'), # binary or
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):
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asm = dis_single(line)
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self.assertIn(elem, asm, asm)
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self.assertNotIn('BINARY_', asm)
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# Verify that unfoldables are skipped
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asm = dis_single('a=2+"b"')
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self.assertIn('(2)', asm)
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self.assertIn("('b')", asm)
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# Verify that large sequences do not result from folding
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asm = dis_single('a="x"*1000')
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self.assertIn('(1000)', asm)
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def test_folding_of_unaryops_on_constants(self):
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for line, elem in (
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('-0.5', '(-0.5)'), # unary negative
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('~-2', '(1)'), # unary invert
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('+1', '(1)'), # unary positive
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):
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asm = dis_single(line)
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self.assertIn(elem, asm, asm)
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self.assertNotIn('UNARY_', asm)
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# Verify that unfoldables are skipped
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for line, elem in (
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('-"abc"', "('abc')"), # unary negative
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('~"abc"', "('abc')"), # unary invert
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):
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asm = dis_single(line)
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self.assertIn(elem, asm, asm)
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self.assertIn('UNARY_', asm)
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def test_elim_extra_return(self):
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# RETURN LOAD_CONST None RETURN --> RETURN
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def f(x):
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return x
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asm = disassemble(f)
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self.assertNotIn('LOAD_CONST', asm)
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self.assertNotIn('(None)', asm)
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self.assertEqual(asm.split().count('RETURN_VALUE'), 1)
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def test_elim_jump_to_return(self):
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# JUMP_FORWARD to RETURN --> RETURN
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def f(cond, true_value, false_value):
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return true_value if cond else false_value
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asm = disassemble(f)
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self.assertNotIn('JUMP_FORWARD', asm)
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self.assertNotIn('JUMP_ABSOLUTE', asm)
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self.assertEqual(asm.split().count('RETURN_VALUE'), 2)
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def test_elim_jump_after_return1(self):
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# Eliminate dead code: jumps immediately after returns can't be reached
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def f(cond1, cond2):
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if cond1: return 1
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if cond2: return 2
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while 1:
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return 3
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while 1:
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if cond1: return 4
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return 5
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return 6
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asm = disassemble(f)
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self.assertNotIn('JUMP_FORWARD', asm)
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self.assertNotIn('JUMP_ABSOLUTE', asm)
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self.assertEqual(asm.split().count('RETURN_VALUE'), 6)
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def test_elim_jump_after_return2(self):
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# Eliminate dead code: jumps immediately after returns can't be reached
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def f(cond1, cond2):
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while 1:
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if cond1: return 4
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asm = disassemble(f)
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self.assertNotIn('JUMP_FORWARD', asm)
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# There should be one jump for the while loop.
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self.assertEqual(asm.split().count('JUMP_ABSOLUTE'), 1)
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self.assertEqual(asm.split().count('RETURN_VALUE'), 2)
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def test_make_function_doesnt_bail(self):
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def f():
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def g()->1+1:
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pass
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return g
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asm = disassemble(f)
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self.assertNotIn('BINARY_ADD', asm)
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def test_constant_folding(self):
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# Issue #11244: aggressive constant folding.
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exprs = [
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"3 * -5",
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"-3 * 5",
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"2 * (3 * 4)",
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"(2 * 3) * 4",
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"(-1, 2, 3)",
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"(1, -2, 3)",
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"(1, 2, -3)",
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"(1, 2, -3) * 6",
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"lambda x: x in {(3 * -5) + (-1 - 6), (1, -2, 3) * 2, None}",
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]
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for e in exprs:
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asm = dis_single(e)
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self.assertNotIn('UNARY_', asm, e)
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self.assertNotIn('BINARY_', asm, e)
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self.assertNotIn('BUILD_', asm, e)
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def test_main(verbose=None):
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import sys
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from test import support
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test_classes = (TestTranforms,)
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support.run_unittest(*test_classes)
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# verify reference counting
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if verbose and hasattr(sys, "gettotalrefcount"):
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import gc
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counts = [None] * 5
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for i in range(len(counts)):
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support.run_unittest(*test_classes)
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gc.collect()
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counts[i] = sys.gettotalrefcount()
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print(counts)
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if __name__ == "__main__":
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test_main(verbose=True)
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