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			239 lines
		
	
	
	
		
			8.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			239 lines
		
	
	
	
		
			8.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
import dis
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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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    dis.dis(func)
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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.assertTrue(elem not in asm)
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        for elem in ('POP_JUMP_IF_TRUE',):
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            self.assertTrue(elem in 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.assertTrue(elem in 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.assertTrue(elem not in asm)
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            for elem in ('LOAD_CONST', '('+name+')'):
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                self.assertTrue(elem in 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.assertTrue('LOAD_CONST' in disassemble(f))
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        self.assertTrue('LOAD_GLOBAL' not in 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.assertTrue(elem not in asm)
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        for elem in ('JUMP_ABSOLUTE',):
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            self.assertTrue(elem in 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.assertTrue(elem in asm)
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            self.assertTrue('BUILD_TUPLE' not in asm)
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            self.assertTrue('UNPACK_TUPLE' not in 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.assertTrue(elem in asm)
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            self.assertTrue('BUILD_TUPLE' not in 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_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.assertTrue(elem in asm, asm)
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            self.assertTrue('BINARY_' not in 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.assertTrue('(2)' in asm)
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        self.assertTrue("('b')" in 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.assertTrue('(1000)' in 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.assertTrue(elem in asm, asm)
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            self.assertTrue('UNARY_' not in 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.assertTrue(elem in asm, asm)
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            self.assertTrue('UNARY_' in 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.assertTrue('LOAD_CONST' not in asm)
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        self.assertTrue('(None)' not in 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.assertTrue('JUMP_FORWARD' not in asm)
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        self.assertTrue('JUMP_ABSOLUTE' not in 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.assertTrue('JUMP_FORWARD' not in asm)
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        self.assertTrue('JUMP_ABSOLUTE' not in 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.assertTrue('JUMP_FORWARD' not in 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.assertTrue('BINARY_ADD' not in asm)
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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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