text: import dis
  import unittest
  
  from test.support.bytecode_helper import BytecodeTestCase
  
  
  def count_instr_recursively(f, opname):
      count = 0
      for instr in dis.get_instructions(f):
          if instr.opname == opname:
              count += 1
      if hasattr(f, '__code__'):
          f = f.__code__
      for c in f.co_consts:
          if hasattr(c, 'co_code'):
              count += count_instr_recursively(c, opname)
      return count
  
  
  class TestTranforms(BytecodeTestCase):
  
      def check_jump_targets(self, code):
          instructions = list(dis.get_instructions(code))
          targets = {instr.offset: instr for instr in instructions}
          for instr in instructions:
              if 'JUMP_' not in instr.opname:
                  continue
              tgt = targets[instr.argval]
              # jump to unconditional jump
              if tgt.opname in ('JUMP_ABSOLUTE', 'JUMP_FORWARD'):
                  self.fail(f'{instr.opname} at {instr.offset} '
                            f'jumps to {tgt.opname} at {tgt.offset}')
              # unconditional jump to RETURN_VALUE
              if (instr.opname in ('JUMP_ABSOLUTE', 'JUMP_FORWARD') and
                  tgt.opname == 'RETURN_VALUE'):
                  self.fail(f'{instr.opname} at {instr.offset} '
                            f'jumps to {tgt.opname} at {tgt.offset}')
              # JUMP_IF_*_OR_POP jump to conditional jump
              if '_OR_POP' in instr.opname and 'JUMP_IF_' in tgt.opname:
                  self.fail(f'{instr.opname} at {instr.offset} '
                            f'jumps to {tgt.opname} at {tgt.offset}')
  
      def check_lnotab(self, code):
          "Check that the lnotab byte offsets are sensible."
          code = dis._get_code_object(code)
          lnotab = list(dis.findlinestarts(code))
          # Don't bother checking if the line info is sensible, because
          # most of the line info we can get at comes from lnotab.
          min_bytecode = min(t[0] for t in lnotab)
          max_bytecode = max(t[0] for t in lnotab)
          self.assertGreaterEqual(min_bytecode, 0)
          self.assertLess(max_bytecode, len(code.co_code))
          # This could conceivably test more (and probably should, as there
          # aren't very many tests of lnotab), if peepholer wasn't scheduled
          # to be replaced anyway.
  
      def test_unot(self):
          # UNARY_NOT POP_JUMP_IF_FALSE  -->  POP_JUMP_IF_TRUE'
          def unot(x):
              if not x == 2:
                  del x
          self.assertNotInBytecode(unot, 'UNARY_NOT')
          self.assertNotInBytecode(unot, 'POP_JUMP_IF_FALSE')
          self.assertInBytecode(unot, 'POP_JUMP_IF_TRUE')
          self.check_lnotab(unot)
  
      def test_elim_inversion_of_is_or_in(self):
          for line, cmp_op, invert in (
              ('not a is b', 'IS_OP', 1,),
              ('not a is not b', 'IS_OP', 0,),
              ('not a in b', 'CONTAINS_OP', 1,),
              ('not a not in b', 'CONTAINS_OP', 0,),
              ):
              code = compile(line, '', 'single')
              self.assertInBytecode(code, cmp_op, invert)
              self.check_lnotab(code)
  
      def test_global_as_constant(self):
          # LOAD_GLOBAL None/True/False  -->  LOAD_CONST None/True/False
          def f():
              x = None
              x = None
              return x
          def g():
              x = True
              return x
          def h():
              x = False
              return x
  
          for func, elem in ((f, None), (g, True), (h, False)):
              self.assertNotInBytecode(func, 'LOAD_GLOBAL')
              self.assertInBytecode(func, 'LOAD_CONST', elem)
              self.check_lnotab(func)
  
          def f():
              'Adding a docstring made this test fail in Py2.5.0'
              return None
  
          self.assertNotInBytecode(f, 'LOAD_GLOBAL')
          self.assertInBytecode(f, 'LOAD_CONST', None)
          self.check_lnotab(f)
  
      def test_while_one(self):
          # Skip over:  LOAD_CONST trueconst  POP_JUMP_IF_FALSE xx
          def f():
              while 1:
                  pass
              return list
          for elem in ('LOAD_CONST', 'POP_JUMP_IF_FALSE'):
              self.assertNotInBytecode(f, elem)
          for elem in ('JUMP_ABSOLUTE',):
              self.assertInBytecode(f, elem)
          self.check_lnotab(f)
  
      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',),
              ):
              code = compile(line,'','single')
              self.assertInBytecode(code, elem)
              self.assertNotInBytecode(code, 'BUILD_TUPLE')
              self.assertNotInBytecode(code, 'UNPACK_TUPLE')
              self.check_lnotab(code)
  
      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)),
              ):
              code = compile(line,'','single')
              self.assertInBytecode(code, 'LOAD_CONST', elem)
              self.assertNotInBytecode(code, 'BUILD_TUPLE')
              self.check_lnotab(code)
  
          # Long tuples should be folded too.
          code = compile(repr(tuple(range(10000))),'','single')
          self.assertNotInBytecode(code, 'BUILD_TUPLE')
          # One LOAD_CONST for the tuple, one for the None return value
          load_consts = [instr for instr in dis.get_instructions(code)
                                if instr.opname == 'LOAD_CONST']
          self.assertEqual(len(load_consts), 2)
          self.check_lnotab(code)
  
          # 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,
              ],)
          self.check_lnotab(crater)
  
      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)),
              ):
              code = compile(line, '', 'single')
              self.assertInBytecode(code, 'LOAD_CONST', elem)
              self.assertNotInBytecode(code, 'BUILD_LIST')
              self.check_lnotab(code)
  
      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})),
              ):
              code = compile(line, '', 'single')
              self.assertNotInBytecode(code, 'BUILD_SET')
              self.assertInBytecode(code, 'LOAD_CONST', elem)
              self.check_lnotab(code)
  
          # 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.check_lnotab(f)
  
          self.assertTrue(not g(3))
          self.assertTrue(g(4))
          self.check_lnotab(g)
  
  
      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
              ):
              code = compile(line, '', 'single')
              self.assertInBytecode(code, 'LOAD_CONST', elem)
              for instr in dis.get_instructions(code):
                  self.assertFalse(instr.opname.startswith('BINARY_'))
              self.check_lnotab(code)
  
          # Verify that unfoldables are skipped
          code = compile('a=2+"b"', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', 2)
          self.assertInBytecode(code, 'LOAD_CONST', 'b')
          self.check_lnotab(code)
  
          # Verify that large sequences do not result from folding
          code = compile('a="x"*10000', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', 10000)
          self.assertNotIn("x"*10000, code.co_consts)
          self.check_lnotab(code)
          code = compile('a=1<<1000', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', 1000)
          self.assertNotIn(1<<1000, code.co_consts)
          self.check_lnotab(code)
          code = compile('a=2**1000', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', 1000)
          self.assertNotIn(2**1000, code.co_consts)
          self.check_lnotab(code)
  
      def test_binary_subscr_on_unicode(self):
          # valid code get optimized
          code = compile('"foo"[0]', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', 'f')
          self.assertNotInBytecode(code, 'BINARY_SUBSCR')
          self.check_lnotab(code)
          code = compile('"\u0061\uffff"[1]', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', '\uffff')
          self.assertNotInBytecode(code,'BINARY_SUBSCR')
          self.check_lnotab(code)
  
          # With PEP 393, non-BMP char get optimized
          code = compile('"\U00012345"[0]', '', 'single')
          self.assertInBytecode(code, 'LOAD_CONST', '\U00012345')
          self.assertNotInBytecode(code, 'BINARY_SUBSCR')
          self.check_lnotab(code)
  
          # invalid code doesn't get optimized
          # out of range
          code = compile('"fuu"[10]', '', 'single')
          self.assertInBytecode(code, 'BINARY_SUBSCR')
          self.check_lnotab(code)
  
      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
          ):
              code = compile(line, '', 'single')
              self.assertInBytecode(code, 'LOAD_CONST', elem)
              for instr in dis.get_instructions(code):
                  self.assertFalse(instr.opname.startswith('UNARY_'))
              self.check_lnotab(code)
  
          # Check that -0.0 works after marshaling
          def negzero():
              return -(1.0-1.0)
  
          for instr in dis.get_instructions(negzero):
              self.assertFalse(instr.opname.startswith('UNARY_'))
          self.check_lnotab(negzero)
  
          # Verify that unfoldables are skipped
          for line, elem, opname in (
              ('-"abc"', 'abc', 'UNARY_NEGATIVE'),
              ('~"abc"', 'abc', 'UNARY_INVERT'),
          ):
              code = compile(line, '', 'single')
              self.assertInBytecode(code, 'LOAD_CONST', elem)
              self.assertInBytecode(code, opname)
              self.check_lnotab(code)
  
      def test_elim_extra_return(self):
          # RETURN LOAD_CONST None RETURN  -->  RETURN
          def f(x):
              return x
          self.assertNotInBytecode(f, 'LOAD_CONST', None)
          returns = [instr for instr in dis.get_instructions(f)
                            if instr.opname == 'RETURN_VALUE']
          self.assertEqual(len(returns), 1)
          self.check_lnotab(f)
  
      def test_elim_jump_to_return(self):
          # JUMP_FORWARD to RETURN -->  RETURN
          def f(cond, true_value, false_value):
              # Intentionally use two-line expression to test issue37213.
              return (true_value if cond
                      else false_value)
          self.check_jump_targets(f)
          self.assertNotInBytecode(f, 'JUMP_FORWARD')
          self.assertNotInBytecode(f, 'JUMP_ABSOLUTE')
          returns = [instr for instr in dis.get_instructions(f)
                            if instr.opname == 'RETURN_VALUE']
          self.assertEqual(len(returns), 2)
          self.check_lnotab(f)
  
      def test_elim_jump_to_uncond_jump(self):
          # POP_JUMP_IF_FALSE to JUMP_FORWARD --> POP_JUMP_IF_FALSE to non-jump
          def f():
              if a:
                  # Intentionally use two-line expression to test issue37213.
                  if (c
                      or d):
                      foo()
              else:
                  baz()
          self.check_jump_targets(f)
          self.check_lnotab(f)
  
      def test_elim_jump_to_uncond_jump2(self):
          # POP_JUMP_IF_FALSE to JUMP_ABSOLUTE --> POP_JUMP_IF_FALSE to non-jump
          def f():
              while a:
                  # Intentionally use two-line expression to test issue37213.
                  if (c
                      or d):
                      a = foo()
          self.check_jump_targets(f)
          self.check_lnotab(f)
  
      def test_elim_jump_to_uncond_jump3(self):
          # Intentionally use two-line expressions to test issue37213.
          # JUMP_IF_FALSE_OR_POP to JUMP_IF_FALSE_OR_POP --> JUMP_IF_FALSE_OR_POP to non-jump
          def f(a, b, c):
              return ((a and b)
                      and c)
          self.check_jump_targets(f)
          self.check_lnotab(f)
          self.assertEqual(count_instr_recursively(f, 'JUMP_IF_FALSE_OR_POP'), 2)
          # JUMP_IF_TRUE_OR_POP to JUMP_IF_TRUE_OR_POP --> JUMP_IF_TRUE_OR_POP to non-jump
          def f(a, b, c):
              return ((a or b)
                      or c)
          self.check_jump_targets(f)
          self.check_lnotab(f)
          self.assertEqual(count_instr_recursively(f, 'JUMP_IF_TRUE_OR_POP'), 2)
          # JUMP_IF_FALSE_OR_POP to JUMP_IF_TRUE_OR_POP --> POP_JUMP_IF_FALSE to non-jump
          def f(a, b, c):
              return ((a and b)
                      or c)
          self.check_jump_targets(f)
          self.check_lnotab(f)
          self.assertNotInBytecode(f, 'JUMP_IF_FALSE_OR_POP')
          self.assertInBytecode(f, 'JUMP_IF_TRUE_OR_POP')
          self.assertInBytecode(f, 'POP_JUMP_IF_FALSE')
          # JUMP_IF_TRUE_OR_POP to JUMP_IF_FALSE_OR_POP --> POP_JUMP_IF_TRUE to non-jump
          def f(a, b, c):
              return ((a or b)
                      and c)
          self.check_jump_targets(f)
          self.check_lnotab(f)
          self.assertNotInBytecode(f, 'JUMP_IF_TRUE_OR_POP')
          self.assertInBytecode(f, 'JUMP_IF_FALSE_OR_POP')
          self.assertInBytecode(f, 'POP_JUMP_IF_TRUE')
  
      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
          self.assertNotInBytecode(f, 'JUMP_FORWARD')
          self.assertNotInBytecode(f, 'JUMP_ABSOLUTE')
          returns = [instr for instr in dis.get_instructions(f)
                            if instr.opname == 'RETURN_VALUE']
          self.assertLessEqual(len(returns), 6)
          self.check_lnotab(f)
  
      def test_make_function_doesnt_bail(self):
          def f():
              def g()->1+1:
                  pass
              return g
          self.assertNotInBytecode(f, 'BINARY_ADD')
          self.check_lnotab(f)
  
      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:
              code = compile(e, '', 'single')
              for instr in dis.get_instructions(code):
                  self.assertFalse(instr.opname.startswith('UNARY_'))
                  self.assertFalse(instr.opname.startswith('BINARY_'))
                  self.assertFalse(instr.opname.startswith('BUILD_'))
              self.check_lnotab(code)
  
      def test_in_literal_list(self):
          def containtest():
              return x in [a, b]
          self.assertEqual(count_instr_recursively(containtest, 'BUILD_LIST'), 0)
          self.check_lnotab(containtest)
  
      def test_iterate_literal_list(self):
          def forloop():
              for x in [a, b]:
                  pass
          self.assertEqual(count_instr_recursively(forloop, 'BUILD_LIST'), 0)
          self.check_lnotab(forloop)
  
      def test_condition_with_binop_with_bools(self):
          def f():
              if True or False:
                  return 1
              return 0
          self.assertEqual(f(), 1)
          self.check_lnotab(f)
  
      def test_if_with_if_expression(self):
          # Check bpo-37289
          def f(x):
              if (True if x else False):
                  return True
              return False
          self.assertTrue(f(True))
          self.check_lnotab(f)
  
      def test_trailing_nops(self):
          # Check the lnotab of a function that even after trivial
          # optimization has trailing nops, which the lnotab adjustment has to
          # handle properly (bpo-38115).
          def f(x):
              while 1:
                  return 3
              while 1:
                  return 5
              return 6
          self.check_lnotab(f)
  
      def test_assignment_idiom_in_comprehensions(self):
          def listcomp():
              return [y for x in a for y in [f(x)]]
          self.assertEqual(count_instr_recursively(listcomp, 'FOR_ITER'), 1)
          def setcomp():
              return {y for x in a for y in [f(x)]}
          self.assertEqual(count_instr_recursively(setcomp, 'FOR_ITER'), 1)
          def dictcomp():
              return {y: y for x in a for y in [f(x)]}
          self.assertEqual(count_instr_recursively(dictcomp, 'FOR_ITER'), 1)
          def genexpr():
              return (y for x in a for y in [f(x)])
          self.assertEqual(count_instr_recursively(genexpr, 'FOR_ITER'), 1)
  
  
  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_bpo_42057(self):
          for i in range(10):
              try:
                  raise Exception
              except Exception or Exception:
                  pass
  
  if __name__ == "__main__":
      unittest.main()
  