def Compare(*args): """Creates an _ast.Compare node. Args: *args: List which should alternate between regular nodes and _ast.cmpop. Raises: ValueError: If less than 3 args, or odd args are not valid comparison operators. Returns: An _ast.Compare node. """ if len(args) < 3: raise ValueError('Must have at least 3 args') ops = [] comparators = [] for index, arg in enumerate(args): if index % 2 == 1: if not isinstance(arg, _ast.AST): arg = CompareOpMap(arg) if not isinstance(arg, _ast.cmpop): raise ValueError('Odd args must be instances of _ast.cmpop') ops.append(arg) else: if index != 0: comparators.append(_WrapWithName(arg, ctx_type=CtxEnum.LOAD)) return _ast.Compare(left=_WrapWithName(args[0], ctx_type=CtxEnum.LOAD), ops=ops, comparators=comparators)
def make_comparator(i, bytecode): op, arg = bytecode[i][2], bytecode[i][3] if arg not in Statement.CMP_OP_AST_NODE_MAP: return Statement.make_exception(i, bytecode) cmp_op = Statement.CMP_OP_AST_NODE_MAP[arg]() i, rhs = Statement.make_expr(i - 1, bytecode) i, lhs = Statement.make_expr(i - 1, bytecode) comp_stmt = _ast.Compare(lhs, [cmp_op], [rhs]) return i, comp_stmt
def COMPARE_OP(self, instr): op = instr.arg right = self.ast_stack.pop() expr = self.ast_stack.pop() OP = CMP_OPMAP[op] compare = _ast.Compare(left=expr, ops=[OP()], comparators=[right], lineno=instr.lineno, col_offset=0) self.ast_stack.append(compare)
def test_compare(self): import ast def _mod(mod, msg=None, mode="exec", exc=ValueError): mod.lineno = mod.col_offset = 0 ast.fix_missing_locations(mod) exc = raises(exc, compile, mod, "<test>", mode) if msg is not None: assert msg in str(exc.value) def _expr(node, msg=None, exc=ValueError): mod = ast.Module([ast.Expr(node)]) _mod(mod, msg, exc=exc) left = ast.Name("x", ast.Load()) comp = ast.Compare(left, [ast.In()], []) _expr(comp, "no comparators") comp = ast.Compare(left, [ast.In()], [ast.Num(4), ast.Num(5)]) _expr(comp, "different number of comparators and operands") comp = ast.Compare(ast.Num("blah"), [ast.In()], [left]) _expr(comp, "non-numeric", exc=TypeError) comp = ast.Compare(left, [ast.In()], [ast.Num("blah")]) _expr(comp, "non-numeric", exc=TypeError)
def compare_expr(left: _ast.expr, ops: List[_ast.cmpop], comparators: List[_ast.expr]) -> _ast.Compare: return _ast.Compare(left=left, ops=ops, comparators=comparators)
def _cfa(body, state, on_gen): assert isinstance(on_gen, list) for c in on_gen: assert callable(c) cfg = state.cfg def make_connect(cur_bid): assert isinstance(cur_bid, int) def inner(new_bid): assert isinstance(new_bid, int) state.connect([cur_bid], [new_bid]) return inner def push_block(block): block_id = len(cfg.blocks) assert block_id not in cfg.blocks cfg.blocks[block_id] = block for c in on_gen: c(block_id) return block_id cur_block = [] for b in body: if REDUCE_FORS_TO_WHILES and isinstance(b, _ast.For): if isinstance(b.iter, _ast.Call) and isinstance( b.iter.func, _ast.Name) and b.iter.func.id in ("range", "xrange"): if not b.iter.keywords and not b.iter.starargs and not b.iter.kwargs: end_var = "__wfend_%d_%d_" % (b.lineno, b.col_offset) iter_var = "__wfiter_%d_%d_" % (b.lineno, b.col_offset) if len(b.iter.args) in (1, 2): if len(b.iter.args) == 1: start = _ast.Num(0) end = b.iter.args[0] elif len(b.iter.args) == 2: start = b.iter.args[0] end = b.iter.args[1] else: start = b.iter.args[0] end = b.iter.args[1] cur_block.append( _ast.Assign([ _ast.Name( iter_var, _ast.Store(), not_real=True) ], start, lineno=b.lineno, col_offset=b.col_offset, not_real=True)) cur_block.append( _ast.Assign([ _ast.Name(end_var, _ast.Store(), not_real=True) ], end, lineno=b.lineno, col_offset=b.col_offset, not_real=True)) body = [ _ast.Assign([b.target], _ast.Name(iter_var, _ast.Load(), not_real=True), lineno=b.lineno, col_offset=b.col_offset, not_real=True), _ast.Assign([ _ast.Name( iter_var, _ast.Store(), not_real=True) ], _ast.BinOp( _ast.Name(iter_var, _ast.Load(), not_real=True), _ast.Add(), _ast.Num(1)), lineno=b.lineno, col_offset=b.col_offset, not_real=True) ] + b.body b = _ast.While(_ast.Compare( _ast.Name(iter_var, _ast.Load(), not_real=True), [_ast.Lt()], [_ast.Name(end_var, _ast.Load(), not_real=True)], lineno=b.lineno, col_offset=b.col_offset, not_real=True), body, b.orelse, not_real=True) if isinstance(b, ( _ast.Assign, _ast.AugAssign, _ast.ClassDef, _ast.Delete, _ast.Exec, _ast.Expr, _ast.FunctionDef, _ast.Global, _ast.Import, _ast.ImportFrom, _ast.Print, _ast.Pass, )): cur_block.append(b) elif isinstance(b, _ast.Assert): cur_block.append(b) if isinstance(b.test, _ast.Call) and isinstance( b.test.func, _ast.Name ) and b.test.func.id == "isinstance" and isinstance( b.test.args[0], _ast.Name) and isinstance( b.test.args[1], _ast.Name): varname = b.test.args[0].id cast = _ast.Call(_ast.Name( "__cast__", _ast.Load(), not_real=True, **pos(b)), [ _ast.Name( varname, _ast.Store(), not_real=True, **pos(b)), b.test.args[1] ], [], None, None, not_real=True, **pos(b)) assign = _ast.Assign([ _ast.Name(varname, _ast.Store(), not_real=True, **pos(b)) ], cast, not_real=True, lineno=b.lineno, col_offset=b.col_offset) cur_block.append(assign) elif isinstance(b, (_ast.Break, _ast.Continue)): f = state.add_break if isinstance( b, _ast.Break) else state.add_continue if cur_block: j = Jump() cur_block.append(j) block_id = push_block(cur_block) f(j.set_dest) f(make_connect(block_id)) else: for c in on_gen: f(c) return [] elif isinstance(b, _ast.If): br = Branch(b.test, lineno=b.lineno) cur_block.append(br) next_block = push_block(cur_block) on_gen = None # make sure this doesn't get used cur_block = [] gen_true = [br.set_true, make_connect(next_block)] gen_false = [br.set_false, make_connect(next_block)] if ENFORCE_NO_MULTIMULTI: on_gen = gen_true j1 = Jump() gen_true = [make_connect(push_block([j1])), j1.set_dest] on_gen = gen_false j2 = Jump() gen_false = [make_connect(push_block([j2])), j2.set_dest] on_gen = None assert b.body body = b.body if isinstance(b.test, _ast.Call) and isinstance( b.test.func, _ast.Name ) and b.test.func.id == "isinstance" and isinstance( b.test.args[0], _ast.Name) and isinstance( b.test.args[1], _ast.Name): varname = b.test.args[0].id cast = _ast.Call(_ast.Name( "__cast__", _ast.Load(), not_real=True, **pos(b)), [ _ast.Name( varname, _ast.Store(), not_real=True, **pos(b)), b.test.args[1] ], [], None, None, not_real=True, **pos(b)) assign = _ast.Assign([ _ast.Name(varname, _ast.Store(), not_real=True, **pos(b)) ], cast, not_real=True, lineno=b.lineno, col_offset=b.col_offset) body = [assign] + body if ADD_IF_ASSERTS: body = [_ast.Assert(b.test, None, not_real=True, **pos(b)) ] + body ending_gen = _cfa(body, state, gen_true) if b.orelse: ending_gen += _cfa(b.orelse, state, gen_false) else: ending_gen += gen_false on_gen = ending_gen if not on_gen and PRUNE_UNREACHABLE_BLOCKS: return [] elif isinstance(b, _ast.TryExcept): j = Jump() cur_block.append(j) next_block = push_block(cur_block) on_gen = [j.set_dest, make_connect(next_block)] cur_block = [] on_gen = _cfa(b.body, state, on_gen) # Set this to evaluate a string to try to defeat simple flow analysis br = Branch(_ast.Str("nonzero")) next_block = push_block([br]) on_except = [br.set_false, make_connect(next_block)] on_fine = [br.set_true, make_connect(next_block)] assert len(b.handlers) >= 1 # for handler in b.handlers: # on_except = _cfa(b.handlers[0].body, state, on_except) if b.orelse: on_fine = _cfa(b.orelse, state, on_fine) if ENFORCE_NO_MULTIMULTI: j = Jump() on_gen = on_fine next_block = push_block([j]) on_fine = [j.set_dest, make_connect(next_block)] j = Jump() on_gen = on_except next_block = push_block([j]) on_except = [j.set_dest, make_connect(next_block)] on_gen = on_fine + on_except cur_block = [] elif isinstance(b, _ast.TryFinally): j = Jump() cur_block.append(j) next_block = push_block(cur_block) on_gen = [j.set_dest, make_connect(next_block)] cur_block = [] on_gen = _cfa(b.body, state, on_gen) on_gen = _cfa(b.finalbody, state, on_gen) elif isinstance(b, _ast.While): # This could also be architected as having no extra block and having two jump statements, but I don't like that if cur_block: j = Jump() cur_block.append(j) on_gen = [make_connect(push_block(cur_block)), j.set_dest] cur_block = [] always_true = False always_false = False if isinstance(b.test, _ast.Name): if b.test.id == "True": always_true = True elif b.test.id == "False": always_false = True elif isinstance(b.test, _ast.Num): if b.test.n: always_true = True else: always_false = True if always_true: br = Jump() on_true = br.set_dest elif always_false: br = Jump() on_false = br.set_dest else: br = Branch(b.test) on_true = br.set_true on_false = br.set_false init_id = push_block([br]) on_gen = None assert cur_block == [] # just checking if not always_false: gen_true = [on_true, make_connect(init_id)] if not always_true: gen_false = [on_false, make_connect(init_id)] if ENFORCE_NO_MULTIMULTI: if not always_false: on_gen = gen_true j1 = Jump() gen_true = [make_connect(push_block([j1])), j1.set_dest] if not always_true: on_gen = gen_false j2 = Jump() gen_false = [make_connect(push_block([j2])), j2.set_dest] on_gen = None ending_gen = [] if not always_false: state.push_loop() assert b.body loop_ending_gen = _cfa(b.body, state, gen_true) loop_ending_gen += state.get_continues() for c in loop_ending_gen: c(init_id) ending_gen = state.get_breaks() state.pop_loop() if not always_true: if b.orelse: ending_gen += _cfa(b.orelse, state, gen_false) else: ending_gen += gen_false on_gen = ending_gen if not on_gen and PRUNE_UNREACHABLE_BLOCKS: return [] elif isinstance(b, _ast.For): iter_func = _ast.Attribute(b.iter, "__iter__", _ast.Load(), not_real=True, lineno=b.lineno, col_offset=b.col_offset) iter_call = _ast.Call(iter_func, [], [], None, None, not_real=True, lineno=b.lineno, col_offset=b.col_offset) # iter_var = _make_temp_name() iter_var = "__foriter_%d_%d_" % (b.lineno, b.col_offset) iter_assign = _ast.Assign( [_ast.Name(iter_var, _ast.Store(), not_real=True, **pos(b))], iter_call, not_real=True, lineno=b.lineno, col_offset=b.col_offset) cur_block.append(iter_assign) j = Jump() cur_block.append(j) on_gen = [make_connect(push_block(cur_block)), j.set_dest] cur_block = [] br = Branch( HasNext( _ast.Name(iter_var, _ast.Load(), not_real=True, **pos(b)), **pos(b)), **pos(b)) init_id = push_block([br]) on_gen = None assert cur_block == [] # just checking gen_true = [br.set_true, make_connect(init_id)] gen_false = [br.set_false, make_connect(init_id)] if ENFORCE_NO_MULTIMULTI: on_gen = gen_true j1 = Jump() gen_true = [make_connect(push_block([j1])), j1.set_dest] on_gen = gen_false j2 = Jump() gen_false = [make_connect(push_block([j2])), j2.set_dest] on_gen = None ending_gen = [] state.push_loop() next_func = _ast.Attribute(_ast.Name(iter_var, _ast.Load(), not_real=True, **pos(b)), "next", _ast.Load(), not_real=True, lineno=b.lineno, col_offset=b.col_offset) next = _ast.Call(next_func, [], [], None, None, not_real=True, lineno=b.lineno, col_offset=b.col_offset) next_assign = _ast.Assign([b.target], next, not_real=True, lineno=b.lineno, col_offset=b.col_offset) next_iter_gen = _cfa([next_assign] + b.body, state, gen_true) next_iter_gen += state.get_continues() for c in next_iter_gen: c(init_id) loop_done_gen = list(state.get_breaks()) state.pop_loop() if b.orelse: # if b.orelse and loop_ending_blocks: loop_done_gen += _cfa(b.orelse, state, gen_false) else: loop_done_gen += gen_false on_gen = loop_done_gen if not on_gen and PRUNE_UNREACHABLE_BLOCKS: return [] elif isinstance(b, (_ast.Return, _ast.Raise)): cur_block.append(b) block_id = push_block(cur_block) state.returns.append(make_connect(block_id)) return [] elif isinstance(b, _ast.With): # XXX totally ignores the functionality of with statements # Have to save the context manager because the expression might not be valid later mgr_name = "__mgr_%s_%s_" % (b.lineno, b.col_offset) save_mgr = _ast.Assign([ _ast.Name(mgr_name, _ast.Store(), lineno=b.lineno, col_offset=b.col_offset, not_real=True) ], b.context_expr, lineno=b.lineno, col_offset=b.col_offset, not_real=True) enter_func = _ast.Attribute(_ast.Name(mgr_name, _ast.Load(), lineno=b.lineno, col_offset=b.col_offset, not_real=True), "__enter__", _ast.Load(), lineno=b.lineno, col_offset=b.col_offset, not_real=True) bind = _ast.Call(enter_func, [], [], None, None, lineno=b.lineno, col_offset="__enter__()", not_real=True) if b.optional_vars: assert isinstance(b.optional_vars, _ast.AST) init = _ast.Assign([b.optional_vars], bind, lineno=b.lineno, col_offset=b.col_offset, not_real=True) else: init = _ast.Expr(bind, lineno=b.lineno, col_offset=b.col_offset, not_real=True) exit_func = _ast.Attribute(_ast.Name(mgr_name, _ast.Load(), lineno=b.lineno, col_offset=b.col_offset, not_real=True), "__exit__", _ast.Load(), lineno=b.lineno, col_offset=b.col_offset, not_real=True) if SIMPLE_WITH_EXIT: exit_call = _ast.Call(exit_func, [], [], None, None, lineno=b.lineno, col_offset=b.col_offset, not_real=True) else: none_ = _ast.Name("None", _ast.Load(), lineno=b.lineno, col_offset=b.col_offset, not_real=True) exit_call = _ast.Call(exit_func, [none_, none_, none_], [], None, None, lineno=b.lineno, col_offset=b.col_offset, not_real=True) exit = _ast.Expr(exit_call, lineno=b.lineno, col_offset="__exit__()", not_real=True) cur_block.extend([save_mgr, init]) j = Jump() cur_block.append(j) next_block = push_block(cur_block) on_gen = [j.set_dest, make_connect(next_block)] cur_block = [] body = b.body + [exit] next_gen = _cfa(body, state, on_gen) on_gen = next_gen else: raise Exception(b) if cur_block: j = Jump() cur_block.append(j) next = push_block(cur_block) return [j.set_dest, make_connect(next)] return on_gen return on_gen