import dis import re import sys from io import StringIO import unittest from math import copysign def disassemble(func): f = StringIO() tmp = sys.stdout sys.stdout = f try: dis.dis(func) finally: sys.stdout = tmp result = f.getvalue() f.close() return result def dis_single(line): return disassemble(compile(line, '', 'single')) class TestTranforms(unittest.TestCase): def test_unot(self): # UNARY_NOT POP_JUMP_IF_FALSE --> POP_JUMP_IF_TRUE' def unot(x): if not x == 2: del x asm = disassemble(unot) for elem in ('UNARY_NOT', 'POP_JUMP_IF_FALSE'): self.assertNotIn(elem, asm) for elem in ('POP_JUMP_IF_TRUE',): self.assertIn(elem, asm) def test_elim_inversion_of_is_or_in(self): for line, elem in ( ('not a is b', '(is not)',), ('not a in b', '(not in)',), ('not a is not b', '(is)',), ('not a not in b', '(in)',), ): asm = dis_single(line) self.assertIn(elem, asm) def test_global_as_constant(self): # LOAD_GLOBAL None/True/False --> LOAD_CONST None/True/False def f(x): None None return x def g(x): True return x def h(x): False return x for func, name in ((f, 'None'), (g, 'True'), (h, 'False')): asm = disassemble(func) for elem in ('LOAD_GLOBAL',): self.assertNotIn(elem, asm) for elem in ('LOAD_CONST', '('+name+')'): self.assertIn(elem, asm) def f(): 'Adding a docstring made this test fail in Py2.5.0' return None self.assertIn('LOAD_CONST', disassemble(f)) self.assertNotIn('LOAD_GLOBAL', disassemble(f)) def test_while_one(self): # Skip over: LOAD_CONST trueconst POP_JUMP_IF_FALSE xx def f(): while 1: pass return list asm = disassemble(f) for elem in ('LOAD_CONST', 'POP_JUMP_IF_FALSE'): self.assertNotIn(elem, asm) for elem in ('JUMP_ABSOLUTE',): self.assertIn(elem, asm) def test_pack_unpack(self): for line, elem in ( ('a, = a,', 'LOAD_CONST',), ('a, b = a, b', 'ROT_TWO',), ('a, b, c = a, b, c', 'ROT_THREE',), ): asm = dis_single(line) self.assertIn(elem, asm) self.assertNotIn('BUILD_TUPLE', asm) self.assertNotIn('UNPACK_TUPLE', asm) def test_folding_of_tuples_of_constants(self): for line, elem in ( ('a = 1,2,3', '((1, 2, 3))'), ('("a","b","c")', "(('a', 'b', 'c'))"), ('a,b,c = 1,2,3', '((1, 2, 3))'), ('(None, 1, None)', '((None, 1, None))'), ('((1, 2), 3, 4)', '(((1, 2), 3, 4))'), ): asm = dis_single(line) self.assertIn(elem, asm) self.assertNotIn('BUILD_TUPLE', asm) # Long tuples should be folded too. asm = dis_single(repr(tuple(range(10000)))) # One LOAD_CONST for the tuple, one for the None return value self.assertEqual(asm.count('LOAD_CONST'), 2) self.assertNotIn('BUILD_TUPLE', asm) # Bug 1053819: Tuple of constants misidentified when presented with: # . . . opcode_with_arg 100 unary_opcode BUILD_TUPLE 1 . . . # The following would segfault upon compilation def crater(): (~[ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ],) def test_folding_of_lists_of_constants(self): for line, elem in ( # in/not in constants with BUILD_LIST should be folded to a tuple: ('a in [1,2,3]', '(1, 2, 3)'), ('a not in ["a","b","c"]', "(('a', 'b', 'c'))"), ('a in [None, 1, None]', '((None, 1, None))'), ('a not in [(1, 2), 3, 4]', '(((1, 2), 3, 4))'), ): asm = dis_single(line) self.assertIn(elem, asm) self.assertNotIn('BUILD_LIST', asm) def test_folding_of_sets_of_constants(self): for line, elem in ( # in/not in constants with BUILD_SET should be folded to a frozenset: ('a in {1,2,3}', frozenset({1, 2, 3})), ('a not in {"a","b","c"}', frozenset({'a', 'c', 'b'})), ('a in {None, 1, None}', frozenset({1, None})), ('a not in {(1, 2), 3, 4}', frozenset({(1, 2), 3, 4})), ('a in {1, 2, 3, 3, 2, 1}', frozenset({1, 2, 3})), ): asm = dis_single(line) self.assertNotIn('BUILD_SET', asm) # Verify that the frozenset 'elem' is in the disassembly # The ordering of the elements in repr( frozenset ) isn't # guaranteed, so we jump through some hoops to ensure that we have # the frozenset we expect: self.assertIn('frozenset', asm) # Extract the frozenset literal from the disassembly: m = re.match(r'.*(frozenset\({.*}\)).*', asm, re.DOTALL) self.assertTrue(m) self.assertEqual(eval(m.group(1)), elem) # Ensure that the resulting code actually works: def f(a): return a in {1, 2, 3} def g(a): return a not in {1, 2, 3} self.assertTrue(f(3)) self.assertTrue(not f(4)) self.assertTrue(not g(3)) self.assertTrue(g(4)) def test_folding_of_binops_on_constants(self): for line, elem in ( ('a = 2+3+4', '(9)'), # chained fold ('"@"*4', "('@@@@')"), # check string ops ('a="abc" + "def"', "('abcdef')"), # check string ops ('a = 3**4', '(81)'), # binary power ('a = 3*4', '(12)'), # binary multiply ('a = 13//4', '(3)'), # binary floor divide ('a = 14%4', '(2)'), # binary modulo ('a = 2+3', '(5)'), # binary add ('a = 13-4', '(9)'), # binary subtract ('a = (12,13)[1]', '(13)'), # binary subscr ('a = 13 << 2', '(52)'), # binary lshift ('a = 13 >> 2', '(3)'), # binary rshift ('a = 13 & 7', '(5)'), # binary and ('a = 13 ^ 7', '(10)'), # binary xor ('a = 13 | 7', '(15)'), # binary or ): asm = dis_single(line) self.assertIn(elem, asm, asm) self.assertNotIn('BINARY_', asm) # Verify that unfoldables are skipped asm = dis_single('a=2+"b"') self.assertIn('(2)', asm) self.assertIn("('b')", asm) # Verify that large sequences do not result from folding asm = dis_single('a="x"*1000') self.assertIn('(1000)', asm) def test_binary_subscr_on_unicode(self): # valid code get optimized asm = dis_single('"foo"[0]') self.assertIn("('f')", asm) self.assertNotIn('BINARY_SUBSCR', asm) asm = dis_single('"\u0061\uffff"[1]') self.assertIn("('\\uffff')", asm) self.assertNotIn('BINARY_SUBSCR', asm) asm = dis_single('"\U00012345abcdef"[3]') self.assertIn("('c')", asm) self.assertNotIn('BINARY_SUBSCR', asm) # invalid code doesn't get optimized # out of range asm = dis_single('"fuu"[10]') self.assertIn('BINARY_SUBSCR', asm) def test_folding_of_unaryops_on_constants(self): for line, elem in ( ('-0.5', '(-0.5)'), # unary negative ('-0.0', '(-0.0)'), # -0.0 ('-(1.0-1.0)','(-0.0)'), # -0.0 after folding ('-0', '(0)'), # -0 ('~-2', '(1)'), # unary invert ('+1', '(1)'), # unary positive ): asm = dis_single(line) self.assertIn(elem, asm, asm) self.assertNotIn('UNARY_', asm) # Check that -0.0 works after marshaling def negzero(): return -(1.0-1.0) self.assertNotIn('UNARY_', disassemble(negzero)) self.assertTrue(copysign(1.0, negzero()) < 0) # Verify that unfoldables are skipped for line, elem in ( ('-"abc"', "('abc')"), # unary negative ('~"abc"', "('abc')"), # unary invert ): asm = dis_single(line) self.assertIn(elem, asm, asm) self.assertIn('UNARY_', asm) def test_elim_extra_return(self): # RETURN LOAD_CONST None RETURN --> RETURN def f(x): return x asm = disassemble(f) self.assertNotIn('LOAD_CONST', asm) self.assertNotIn('(None)', asm) self.assertEqual(asm.split().count('RETURN_VALUE'), 1) def test_elim_jump_to_return(self): # JUMP_FORWARD to RETURN --> RETURN def f(cond, true_value, false_value): return true_value if cond else false_value asm = disassemble(f) self.assertNotIn('JUMP_FORWARD', asm) self.assertNotIn('JUMP_ABSOLUTE', asm) self.assertEqual(asm.split().count('RETURN_VALUE'), 2) def test_elim_jump_after_return1(self): # Eliminate dead code: jumps immediately after returns can't be reached def f(cond1, cond2): if cond1: return 1 if cond2: return 2 while 1: return 3 while 1: if cond1: return 4 return 5 return 6 asm = disassemble(f) self.assertNotIn('JUMP_FORWARD', asm) self.assertNotIn('JUMP_ABSOLUTE', asm) self.assertEqual(asm.split().count('RETURN_VALUE'), 6) def test_elim_jump_after_return2(self): # Eliminate dead code: jumps immediately after returns can't be reached def f(cond1, cond2): while 1: if cond1: return 4 asm = disassemble(f) self.assertNotIn('JUMP_FORWARD', asm) # There should be one jump for the while loop. self.assertEqual(asm.split().count('JUMP_ABSOLUTE'), 1) self.assertEqual(asm.split().count('RETURN_VALUE'), 2) def test_make_function_doesnt_bail(self): def f(): def g()->1+1: pass return g asm = disassemble(f) self.assertNotIn('BINARY_ADD', asm) def test_constant_folding(self): # Issue #11244: aggressive constant folding. exprs = [ "3 * -5", "-3 * 5", "2 * (3 * 4)", "(2 * 3) * 4", "(-1, 2, 3)", "(1, -2, 3)", "(1, 2, -3)", "(1, 2, -3) * 6", "lambda x: x in {(3 * -5) + (-1 - 6), (1, -2, 3) * 2, None}", ] for e in exprs: asm = dis_single(e) self.assertNotIn('UNARY_', asm, e) self.assertNotIn('BINARY_', asm, e) self.assertNotIn('BUILD_', asm, e) class TestBuglets(unittest.TestCase): def test_bug_11510(self): # folded constant set optimization was commingled with the tuple # unpacking optimization which would fail if the set had duplicate # elements so that the set length was unexpected def f(): x, y = {1, 1} return x, y with self.assertRaises(ValueError): f() def test_main(verbose=None): import sys from test import support test_classes = (TestTranforms, TestBuglets) support.run_unittest(*test_classes) # verify reference counting if verbose and hasattr(sys, "gettotalrefcount"): import gc counts = [None] * 5 for i in range(len(counts)): support.run_unittest(*test_classes) gc.collect() counts[i] = sys.gettotalrefcount() print(counts) if __name__ == "__main__": test_main(verbose=True)