# Copyright (c) 2015, 2016 by Rocky Bernstein # Copyright (c) 2005 by Dan Pascu # Copyright (c) 2000-2002 by hartmut Goebel """ Python 3 Generic bytecode scanner/deparser This overlaps various Python3's dis module, but it can be run from Python versions other than the version running this code. Notably, run from Python version 2. Also we *modify* the instruction sequence to assist deparsing code. For example: - we add "COME_FROM" instructions to help in figuring out conditional branching and looping. - LOAD_CONSTs are classified further into the type of thing they load: lambda's, genexpr's, {dict,set,list} comprehension's, - PARAMETER counts appended {CALL,MAKE}_FUNCTION, BUILD_{TUPLE,SET,SLICE} Finally we save token information. """ from __future__ import print_function from collections import namedtuple from array import array from uncompyle6.scanner import Scanner, op_has_argument from xdis.code import iscode from xdis.bytecode import Bytecode from uncompyle6.scanner import Token, parse_fn_counts # Get all the opcodes into globals import xdis.opcodes.opcode_33 as op3 import sys from uncompyle6 import PYTHON3 if PYTHON3: intern = sys.intern globals().update(op3.opmap) # POP_JUMP_IF is used by verify POP_JUMP_TF = (POP_JUMP_IF_TRUE, POP_JUMP_IF_FALSE) class Scanner3(Scanner): def __init__(self, version, show_asm=None, is_pypy=False): super(Scanner3, self).__init__(version, show_asm, is_pypy) # Create opcode classification sets # Note: super initilization above initializes self.opc # Ops that start SETUP_ ... We will COME_FROM with these names # Some blocks and END_ statements. And they can start # a new statement setup_ops = [self.opc.SETUP_LOOP, self.opc.SETUP_EXCEPT, self.opc.SETUP_FINALLY] if self.version >= 3.2: setup_ops.append(self.opc.SETUP_WITH) self.setup_ops = frozenset(setup_ops) self.setup_ops_no_loop = frozenset(setup_ops) - frozenset([self.opc.SETUP_LOOP]) # Opcodes that can start a statement. statement_opcodes = [ self.opc.BREAK_LOOP, self.opc.CONTINUE_LOOP, self.opc.POP_BLOCK, self.opc.STORE_FAST, self.opc.DELETE_FAST, self.opc.STORE_DEREF, self.opc.STORE_GLOBAL, self.opc.DELETE_GLOBAL, self.opc.STORE_NAME, self.opc.DELETE_NAME, self.opc.STORE_ATTR, self.opc.DELETE_ATTR, self.opc.STORE_SUBSCR, self.opc.POP_TOP, self.opc.DELETE_SUBSCR, self.opc.END_FINALLY, self.opc.RETURN_VALUE, self.opc.RAISE_VARARGS, self.opc.PRINT_EXPR, self.opc.JUMP_ABSOLUTE ] self.statement_opcodes = frozenset(statement_opcodes) | self.setup_ops_no_loop # Opcodes that can start a designator non-terminal. # FIXME: JUMP_ABSOLUTE is weird. What's up with that? self.designator_ops = frozenset([ self.opc.STORE_FAST, self.opc.STORE_NAME, self.opc.STORE_GLOBAL, self.opc.STORE_DEREF, self.opc.STORE_ATTR, self.opc.STORE_SUBSCR, self.opc.UNPACK_SEQUENCE, self.opc.JUMP_ABSOLUTE, self.opc.UNPACK_EX ]) if self.version > 3.0: self.jump_if_pop = frozenset([self.opc.JUMP_IF_FALSE_OR_POP, self.opc.JUMP_IF_TRUE_OR_POP]) self.pop_jump_if_pop = frozenset([self.opc.JUMP_IF_FALSE_OR_POP, self.opc.JUMP_IF_TRUE_OR_POP, self.opc.POP_JUMP_IF_TRUE, self.opc.POP_JUMP_IF_FALSE]) # Not really a set, but still clasification-like self.statement_opcode_sequences = [ (self.opc.POP_JUMP_IF_FALSE, self.opc.JUMP_FORWARD), (self.opc.POP_JUMP_IF_FALSE, self.opc.JUMP_ABSOLUTE), (self.opc.POP_JUMP_IF_TRUE, self.opc.JUMP_FORWARD), (self.opc.POP_JUMP_IF_TRUE, self.opc.JUMP_ABSOLUTE)] else: self.jump_if_pop = frozenset([]) self.pop_jump_if_pop = frozenset([]) # Not really a set, but still clasification-like self.statement_opcode_sequences = [ (self.opc.JUMP_FORWARD,), (self.opc.JUMP_ABSOLUTE,), (self.opc.JUMP_FORWARD,), (self.opc.JUMP_ABSOLUTE,)] # Opcodes that take a variable number of arguments # (expr's) varargs_ops = set([ self.opc.BUILD_LIST, self.opc.BUILD_TUPLE, self.opc.BUILD_SET, self.opc.BUILD_SLICE, self.opc.BUILD_MAP, self.opc.UNPACK_SEQUENCE, self.opc.RAISE_VARARGS]) if is_pypy: varargs_ops.add(self.opc.CALL_METHOD) self.varargs_ops = frozenset(varargs_ops) # FIXME: remove the above in favor of: # self.varargs_ops = frozenset(self.opc.hasvargs) def opName(self, offset): return self.opc.opname[self.code[offset]] def ingest(self, co, classname=None, code_objects={}, show_asm=None): """ Pick out tokens from an uncompyle6 code object, and transform them, returning a list of uncompyle6 'Token's. The transformations are made to assist the deparsing grammar. Specificially: - various types of LOAD_CONST's are categorized in terms of what they load - COME_FROM instructions are added to assist parsing control structures - MAKE_FUNCTION and FUNCTION_CALLS append the number of positional arguments Also, when we encounter certain tokens, we add them to a set which will cause custom grammar rules. Specifically, variable arg tokens like MAKE_FUNCTION or BUILD_LIST cause specific rules for the specific number of arguments they take. """ show_asm = self.show_asm if not show_asm else show_asm # show_asm = 'both' if show_asm in ('both', 'before'): bytecode = Bytecode(co, self.opc) for instr in bytecode.get_instructions(co): print(instr._disassemble()) # Container for tokens tokens = [] customize = {} if self.is_pypy: customize['PyPy'] = 1 self.code = array('B', co.co_code) self.build_lines_data(co) self.build_prev_op() bytecode = Bytecode(co, self.opc) # FIXME: put as its own method? # Scan for assertions. Later we will # turn 'LOAD_GLOBAL' to 'LOAD_ASSERT'. # 'LOAD_ASSERT' is used in assert statements. self.load_asserts = set() bs = list(bytecode) n = len(bs) for i in range(n): inst = bs[i] # We need to detect the difference between # "raise AssertionError" and "assert" # If we have a JUMP_FORWARD after the # RAISE_VARARGS then we have a "raise" statement # else we have an "assert" statement. if inst.opname == 'POP_JUMP_IF_TRUE' and i+1 < n: next_inst = bs[i+1] if (next_inst.opname == 'LOAD_GLOBAL' and next_inst.argval == 'AssertionError'): for j in range(i+2, n): raise_inst = bs[j] if raise_inst.opname.startswith('RAISE_VARARGS'): if j+1 >= n or bs[j+1].opname != 'JUMP_FORWARD': self.load_asserts.add(next_inst.offset) pass break pass pass # Get jump targets # Format: {target offset: [jump offsets]} jump_targets = self.find_jump_targets(show_asm) last_op_was_break = False for inst in bytecode: argval = inst.argval if inst.offset in jump_targets: jump_idx = 0 # We want to process COME_FROMs to the same offset to be in *descending* # offset order so we have the larger range or biggest instruction interval # last. (I think they are sorted in increasing order, but for safety # we sort them). That way, specific COME_FROM tags will match up # properly. For example, a "loop" with an "if" nested in it should have the # "loop" tag last so the grammar rule matches that properly. for jump_offset in sorted(jump_targets[inst.offset], reverse=True): come_from_name = 'COME_FROM' opname = self.opName(jump_offset) if opname.startswith('SETUP_'): come_from_type = opname[len('SETUP_'):] come_from_name = 'COME_FROM_%s' % come_from_type pass tokens.append(Token(come_from_name, None, repr(jump_offset), offset='%s_%s' % (inst.offset, jump_idx), has_arg = True, opc=self.opc)) jump_idx += 1 pass pass elif inst.offset in self.else_start: end_offset = self.else_start[inst.offset] tokens.append(Token('ELSE', None, repr(end_offset), offset='%s' % (inst.offset), has_arg = True, opc=self.opc)) pass pattr = inst.argrepr opname = inst.opname op = inst.opcode if opname in ['LOAD_CONST']: const = inst.argval if iscode(const): if const.co_name == '': opname = 'LOAD_LAMBDA' elif const.co_name == '': opname = 'LOAD_GENEXPR' elif const.co_name == '': opname = 'LOAD_DICTCOMP' elif const.co_name == '': opname = 'LOAD_SETCOMP' elif const.co_name == '': opname = 'LOAD_LISTCOMP' # verify() uses 'pattr' for comparison, since 'attr' # now holds Code(const) and thus can not be used # for comparison (todo: think about changing this) # pattr = 'code_object @ 0x%x %s->%s' %\ # (id(const), const.co_filename, const.co_name) pattr = '' else: pattr = const pass elif opname in ('MAKE_FUNCTION', 'MAKE_CLOSURE'): pos_args, name_pair_args, annotate_args = parse_fn_counts(inst.argval) if name_pair_args > 0: opname = '%s_N%d' % (opname, name_pair_args) pass if annotate_args > 0: opname = '%s_A_%d' % (opname, annotate_args) pass opname = '%s_%d' % (opname, pos_args) pattr = ("%d positional, %d keyword pair, %d annotated" % (pos_args, name_pair_args, annotate_args)) tokens.append( Token( type_ = opname, attr = (pos_args, name_pair_args, annotate_args), pattr = pattr, offset = inst.offset, linestart = inst.starts_line, op = op, has_arg = op_has_argument(op, op3), opc = self.opc ) ) continue elif op in self.varargs_ops: pos_args = inst.argval if self.is_pypy and not pos_args and opname == 'BUILD_MAP': opname = 'BUILD_MAP_n' else: opname = '%s_%d' % (opname, pos_args) elif self.is_pypy and opname in ('CALL_METHOD', 'JUMP_IF_NOT_DEBUG'): # The value in the dict is in special cases in semantic actions, such # as CALL_FUNCTION. The value is not used in these cases, so we put # in arbitrary value 0. customize[opname] = 0 elif opname == 'UNPACK_EX': # FIXME: try with scanner and parser by # changing inst.argval before_args = inst.argval & 0xFF after_args = (inst.argval >> 8) & 0xff pattr = "%d before vararg, %d after" % (before_args, after_args) argval = (before_args, after_args) opname = '%s_%d+%d' % (opname, before_args, after_args) elif op == self.opc.JUMP_ABSOLUTE: # Further classify JUMP_ABSOLUTE into backward jumps # which are used in loops, and "CONTINUE" jumps which # may appear in a "continue" statement. The loop-type # and continue-type jumps will help us classify loop # boundaries The continue-type jumps help us get # "continue" statements with would otherwise be turned # into a "pass" statement because JUMPs are sometimes # ignored in rules as just boundary overhead. In # comprehensions we might sometimes classify JUMP_BACK # as CONTINUE, but that's okay since we add a grammar # rule for that. pattr = inst.argval target = self.get_target(inst.offset) if target <= inst.offset: next_opname = self.opname[self.code[inst.offset+3]] if (inst.offset in self.stmts and (self.version != 3.0 or (hasattr(inst, 'linestart'))) and (next_opname not in ('END_FINALLY', 'POP_BLOCK', # Python 3.0 only uses POP_TOP 'POP_TOP'))): if (self.version >= 3.5 or (inst.offset not in self.not_continue) or (tokens[-1].type == 'RETURN_VALUE')): opname = 'CONTINUE' pass else: opname = 'JUMP_BACK' # FIXME: this is a hack to catch stuff like: # if x: continue # the "continue" is not on a new line. # There are other situations where we don't catch # CONTINUE as well. if tokens[-1].type == 'JUMP_BACK' and tokens[-1].attr <= argval: if tokens[-2].type == 'BREAK_LOOP': del tokens[-1] else: # intern is used because we are changing the *previous* token tokens[-1].type = intern('CONTINUE') if last_op_was_break and opname == 'CONTINUE': last_op_was_break = False continue elif op == self.opc.RETURN_VALUE: if inst.offset in self.return_end_ifs: opname = 'RETURN_END_IF' elif inst.offset in self.load_asserts: opname = 'LOAD_ASSERT' last_op_was_break = opname == 'BREAK_LOOP' tokens.append( Token( type_ = opname, attr = argval, pattr = pattr, offset = inst.offset, linestart = inst.starts_line, op = op, has_arg = (op >= op3.HAVE_ARGUMENT), opc = self.opc ) ) pass if show_asm in ('both', 'after'): for t in tokens: print(t) print() return tokens, customize def build_lines_data(self, code_obj): """ Generate various line-related helper data. """ # Offset: lineno pairs, only for offsets which start line. # Locally we use list for more convenient iteration using indices linestarts = list(self.opc.findlinestarts(code_obj)) self.linestarts = dict(linestarts) # Plain set with offsets of first ops on line self.linestart_offsets = set(a for (a, _) in linestarts) # 'List-map' which shows line number of current op and offset of # first op on following line, given offset of op as index self.lines = lines = [] LineTuple = namedtuple('LineTuple', ['l_no', 'next']) # Iterate through available linestarts, and fill # the data for all code offsets encountered until # last linestart offset _, prev_line_no = linestarts[0] offset = 0 for start_offset, line_no in linestarts[1:]: while offset < start_offset: lines.append(LineTuple(prev_line_no, start_offset)) offset += 1 prev_line_no = line_no # Fill remaining offsets with reference to last line number # and code length as start offset of following non-existing line codelen = len(self.code) while offset < codelen: lines.append(LineTuple(prev_line_no, codelen)) offset += 1 def build_prev_op(self): """ Compose 'list-map' which allows to jump to previous op, given offset of current op as index. """ code = self.code codelen = len(code) # 2.x uses prev 3.x uses prev_op. Sigh # Until we get this sorted out. self.prev = self.prev_op = [0] for offset in self.op_range(0, codelen): op = code[offset] for _ in range(self.op_size(op)): self.prev_op.append(offset) def find_jump_targets(self, debug): """ Detect all offsets in a byte code which are jump targets where we might insert a COME_FROM instruction. Return the list of offsets. Return the list of offsets. An instruction can be jumped to in from multiple instructions. """ code = self.code n = len(code) self.structs = [{'type': 'root', 'start': 0, 'end': n-1}] # All loop entry points self.loops = [] # Map fixed jumps to their real destination self.fixed_jumps = {} self.ignore_if = set() self.build_statement_indices() self.else_start = {} # Containers filled by detect_control_flow() self.not_continue = set() self.return_end_ifs = set() self.setup_loop_targets = {} # target given setup_loop offset self.setup_loops = {} # setup_loop offset given target targets = {} for offset in self.op_range(0, n): op = code[offset] # Determine structures and fix jumps in Python versions # since 2.3 self.detect_control_flow(offset, targets) has_arg = (op >= op3.HAVE_ARGUMENT) if has_arg: label = self.fixed_jumps.get(offset) if self.version >= 3.6: oparg = code[offset+1] else: oparg = code[offset+1] + code[offset+2] * 256 next_offset = offset + self.op_size(op) if label is None: if op in op3.hasjrel and op != self.opc.FOR_ITER: label = next_offset + oparg elif op in op3.hasjabs: if op in self.jump_if_pop: if oparg > offset: label = oparg if label is not None and label != -1: targets[label] = targets.get(label, []) + [offset] elif op == self.opc.END_FINALLY and offset in self.fixed_jumps: label = self.fixed_jumps[offset] targets[label] = targets.get(label, []) + [offset] pass pass # DEBUG: if debug in ('both', 'after'): import pprint as pp pp.pprint(self.structs) return targets def build_statement_indices(self): code = self.code start = 0 end = codelen = len(code) # Compose preliminary list of indices with statements, # using plain statement opcodes prelim = self.all_instr(start, end, self.statement_opcodes) # Initialize final container with statements with # preliminary data stmts = self.stmts = set(prelim) # Same for opcode sequences pass_stmts = set() for sequence in self.statement_opcode_sequences: for i in self.op_range(start, end-(len(sequence)+1)): match = True for elem in sequence: if elem != code[i]: match = False break i += self.op_size(code[i]) if match is True: i = self.prev_op[i] stmts.add(i) pass_stmts.add(i) # Initialize statement list with the full data we've gathered so far if pass_stmts: stmt_offset_list = list(stmts) stmt_offset_list.sort() else: stmt_offset_list = prelim # 'List-map' which contains offset of start of # next statement, when op offset is passed as index self.next_stmt = slist = [] last_stmt_offset = -1 i = 0 # Go through all statement offsets for stmt_offset in stmt_offset_list: # Process absolute jumps, but do not remove 'pass' statements # from the set if (code[stmt_offset] == self.opc.JUMP_ABSOLUTE and stmt_offset not in pass_stmts): # If absolute jump occurs in forward direction or it takes off from the # same line as previous statement, this is not a statement target = self.get_target(stmt_offset) if target > stmt_offset or self.lines[last_stmt_offset].l_no == self.lines[stmt_offset].l_no: stmts.remove(stmt_offset) continue # Rewing ops till we encounter non-JUMP_ABSOLUTE one j = self.prev_op[stmt_offset] while code[j] == self.opc.JUMP_ABSOLUTE: j = self.prev_op[j] # If we got here, then it's list comprehension which # is not a statement too if code[j] == self.opc.LIST_APPEND: stmts.remove(stmt_offset) continue # Exclude ROT_TWO + POP_TOP elif (code[stmt_offset] == self.opc.POP_TOP and code[self.prev_op[stmt_offset]] == self.opc.ROT_TWO): stmts.remove(stmt_offset) continue # Exclude FOR_ITER + designators elif code[stmt_offset] in self.designator_ops: j = self.prev_op[stmt_offset] while code[j] in self.designator_ops: j = self.prev_op[j] if code[j] == self.opc.FOR_ITER: stmts.remove(stmt_offset) continue # Add to list another list with offset of current statement, # equal to length of previous statement slist += [stmt_offset] * (stmt_offset-i) last_stmt_offset = stmt_offset i = stmt_offset # Finish filling the list for last statement slist += [codelen] * (codelen-len(slist)) def get_target(self, offset): """ Get target offset for op located at given . """ op = self.code[offset] if self.version >= 3.6: target = self.code[offset+1] if op in self.opc.hasjrel: target += offset + 2 else: target = self.code[offset+1] + self.code[offset+2] * 256 if op in self.opc.hasjrel: target += offset + 3 return target def detect_control_flow(self, offset, targets): """ Detect structures and their boundaries to fix optimized jumps in python2.3+ """ # TODO: check the struct boundaries more precisely -Dan code = self.code op = code[offset] # Detect parent structure parent = self.structs[0] start = parent['start'] end = parent['end'] # Pick inner-most parent for our offset for struct in self.structs: current_start = struct['start'] current_end = struct['end'] if ((current_start <= offset < current_end) and (current_start >= start and current_end <= end)): start = current_start end = current_end parent = struct if op == self.opc.SETUP_LOOP: # We categorize loop types: 'for', 'while', 'while 1' with # possibly suffixes '-loop' and '-else' # Try to find the jump_back instruction of the loop. # It could be a return instruction. if self.version <= 3.5: start = offset+3 else: start = offset+2 target = self.get_target(offset) end = self.restrict_to_parent(target, parent) self.setup_loop_targets[offset] = target self.setup_loops[target] = offset if target != end: self.fixed_jumps[offset] = end (line_no, next_line_byte) = self.lines[offset] jump_back = self.last_instr(start, end, self.opc.JUMP_ABSOLUTE, next_line_byte, False) if jump_back: jump_forward_offset = jump_back+3 else: jump_forward_offset = None return_val_offset1 = self.prev[self.prev[end]] if (jump_back and jump_back != self.prev_op[end] and self.is_jump_forward(jump_forward_offset)): if (code[self.prev_op[end]] == self.opc.RETURN_VALUE or (code[self.prev_op[end]] == self.opc.POP_BLOCK and code[return_val_offset1] == self.opc.RETURN_VALUE)): jump_back = None if not jump_back: jump_back = self.last_instr(start, end, self.opc.RETURN_VALUE) if not jump_back: return jump_back += 2 if_offset = None if code[self.prev_op[next_line_byte]] not in POP_JUMP_TF: if_offset = self.prev[next_line_byte] if if_offset: loop_type = 'while' self.ignore_if.add(if_offset) else: loop_type = 'for' target = next_line_byte end = jump_back + 3 else: if self.get_target(jump_back) >= next_line_byte: jump_back = self.last_instr(start, end, self.opc.JUMP_ABSOLUTE, start, False) if end > jump_back+4 and self.is_jump_forward(end): if self.is_jump_forward(jump_back+4): if self.get_target(jump_back+4) == self.get_target(end): self.fixed_jumps[offset] = jump_back+4 end = jump_back+4 elif target < offset: self.fixed_jumps[offset] = jump_back+4 end = jump_back+4 target = self.get_target(jump_back) if code[target] in (self.opc.FOR_ITER, self.opc.GET_ITER): loop_type = 'for' else: loop_type = 'while' test = self.prev_op[next_line_byte] if test == offset: loop_type = 'while 1' elif self.code[test] in op3.hasjabs+op3.hasjrel: self.ignore_if.add(test) test_target = self.get_target(test) if test_target > (jump_back+3): jump_back = test_target self.not_continue.add(jump_back) self.loops.append(target) self.structs.append({'type': loop_type + '-loop', 'start': target, 'end': jump_back}) if jump_back+3 != end: self.structs.append({'type': loop_type + '-else', 'start': jump_back+3, 'end': end}) elif op in POP_JUMP_TF: start = offset + self.op_size(op) target = self.get_target(offset) rtarget = self.restrict_to_parent(target, parent) prev_op = self.prev_op # Do not let jump to go out of parent struct bounds if target != rtarget and parent['type'] == 'and/or': self.fixed_jumps[offset] = rtarget return # Does this jump to right after another conditional jump that is # not myself? If so, it's part of a larger conditional. # rocky: if we have a conditional jump to the next instruction, then # possibly I am "skipping over" a "pass" or null statement. if ((code[prev_op[target]] in self.pop_jump_if_pop) and (target > offset) and prev_op[target] != offset): self.fixed_jumps[offset] = prev_op[target] self.structs.append({'type': 'and/or', 'start': start, 'end': prev_op[target]}) return # The op offset just before the target jump offset is important # in making a determination of what we have. Save that. pre_rtarget = prev_op[rtarget] # Is it an "and" inside an "if" or "while" block if op == self.opc.POP_JUMP_IF_FALSE: # Search for another POP_JUMP_IF_FALSE targetting the same op, # in current statement, starting from current offset, and filter # everything inside inner 'or' jumps and midline ifs match = self.rem_or(start, self.next_stmt[offset], self.opc.POP_JUMP_IF_FALSE, target) # If we still have any offsets in set, start working on it if match: is_jump_forward = self.is_jump_forward(pre_rtarget) if (is_jump_forward and pre_rtarget not in self.stmts and self.restrict_to_parent(self.get_target(pre_rtarget), parent) == rtarget): if (code[prev_op[pre_rtarget]] == self.opc.JUMP_ABSOLUTE and self.remove_mid_line_ifs([offset]) and target == self.get_target(prev_op[pre_rtarget]) and (prev_op[pre_rtarget] not in self.stmts or self.get_target(prev_op[pre_rtarget]) > prev_op[pre_rtarget]) and 1 == len(self.remove_mid_line_ifs(self.rem_or(start, prev_op[pre_rtarget], POP_JUMP_TF, target)))): pass elif (code[prev_op[pre_rtarget]] == self.opc.RETURN_VALUE and self.remove_mid_line_ifs([offset]) and 1 == (len(set(self.remove_mid_line_ifs(self.rem_or(start, prev_op[pre_rtarget], POP_JUMP_TF, target))) | set(self.remove_mid_line_ifs(self.rem_or(start, prev_op[pre_rtarget], (self.opc.POP_JUMP_IF_FALSE, self.opc.POP_JUMP_IF_TRUE, self.opc.JUMP_ABSOLUTE), pre_rtarget, True)))))): pass else: fix = None jump_ifs = self.all_instr(start, self.next_stmt[offset], self.opc.POP_JUMP_IF_FALSE) last_jump_good = True for j in jump_ifs: if target == self.get_target(j): if self.lines[j].next == j + 3 and last_jump_good: fix = j break else: last_jump_good = False self.fixed_jumps[offset] = fix or match[-1] return else: self.fixed_jumps[offset] = match[-1] return # op == POP_JUMP_IF_TRUE else: next = self.next_stmt[offset] if prev_op[next] == offset: pass elif self.is_jump_forward(next) and target == self.get_target(next): if code[prev_op[next]] == self.opc.POP_JUMP_IF_FALSE: if (code[next] == self.opc.JUMP_FORWARD or target != rtarget or code[prev_op[pre_rtarget]] not in (self.opc.JUMP_ABSOLUTE, self.opc.RETURN_VALUE)): self.fixed_jumps[offset] = prev_op[next] return elif (code[next] == self.opc.JUMP_ABSOLUTE and self.is_jump_forward(target) and self.get_target(target) == self.get_target(next)): self.fixed_jumps[offset] = prev_op[next] return # Don't add a struct for a while test, it's already taken care of if offset in self.ignore_if: return if (code[pre_rtarget] == self.opc.JUMP_ABSOLUTE and pre_rtarget in self.stmts and pre_rtarget != offset and prev_op[pre_rtarget] != offset and not (code[rtarget] == self.opc.JUMP_ABSOLUTE and code[rtarget+3] == self.opc.POP_BLOCK and code[prev_op[pre_rtarget]] != self.opc.JUMP_ABSOLUTE)): rtarget = pre_rtarget # Does the "jump if" jump beyond a jump op? # That is, we have something like: # POP_JUMP_IF_FALSE HERE # ... # JUMP_FORWARD # HERE: # # If so, this can be block inside an "if" statement # or a conditional assignment like: # x = 1 if x else 2 # # There are other contexts we may need to consider # like whether the target is "END_FINALLY" # or if the condition jump is to a forward location if self.is_jump_forward(pre_rtarget): if_end = self.get_target(pre_rtarget) # If the jump target is back, we are looping if (if_end < pre_rtarget and (code[prev_op[if_end]] == self.opc.SETUP_LOOP)): if (if_end > start): return end = self.restrict_to_parent(if_end, parent) self.structs.append({'type': 'if-then', 'start': start, 'end': pre_rtarget}) self.not_continue.add(pre_rtarget) if rtarget < end and ( code[rtarget] not in (self.opc.END_FINALLY, self.opc.JUMP_ABSOLUTE) and code[prev_op[pre_rtarget]] not in (self.opc.POP_EXCEPT, self.opc.END_FINALLY)): self.structs.append({'type': 'else', 'start': rtarget, 'end': end}) self.else_start[rtarget] = end elif self.is_jump_back(pre_rtarget): if_end = rtarget self.structs.append({'type': 'if-then', 'start': start, 'end': pre_rtarget}) self.not_continue.add(pre_rtarget) elif code[pre_rtarget] in (self.opc.RETURN_VALUE, self.opc.BREAK_LOOP): self.structs.append({'type': 'if-then', 'start': start, 'end': rtarget}) # It is important to distingish if this return is inside some sort # except block return jump_prev = prev_op[offset] if self.is_pypy and code[jump_prev] == self.opc.COMPARE_OP: if self.opc.cmp_op[code[jump_prev+1]] == 'exception match': return if self.version >= 3.5: # Python 3.5 may remove as dead code a JUMP # instruction after a RETURN_VALUE. So we check # based on seeing SETUP_EXCEPT various places. if code[rtarget] == self.opc.SETUP_EXCEPT: return # Check that next instruction after pops and jump is # not from SETUP_EXCEPT next_op = rtarget if code[next_op] == self.opc.POP_BLOCK: next_op += self.op_size(self.code[next_op]) if code[next_op] == self.opc.JUMP_ABSOLUTE: next_op += self.op_size(self.code[next_op]) if next_op in targets: for try_op in targets[next_op]: come_from_op = code[try_op] if come_from_op == self.opc.SETUP_EXCEPT: return pass pass if code[pre_rtarget] == self.opc.RETURN_VALUE: self.return_end_ifs.add(pre_rtarget) else: self.fixed_jumps[offset] = rtarget self.not_continue.add(pre_rtarget) elif op == self.opc.SETUP_EXCEPT: target = self.get_target(offset) end = self.restrict_to_parent(target, parent) self.fixed_jumps[offset] = end elif op == self.opc.SETUP_FINALLY: target = self.get_target(offset) end = self.restrict_to_parent(target, parent) self.fixed_jumps[offset] = end elif op in self.jump_if_pop: target = self.get_target(offset) if target > offset: unop_target = self.last_instr(offset, target, self.opc.JUMP_FORWARD, target) if unop_target and code[unop_target+3] != self.opc.ROT_TWO: self.fixed_jumps[offset] = unop_target else: self.fixed_jumps[offset] = self.restrict_to_parent(target, parent) pass pass elif self.version >= 3.5: # 3.5+ has Jump optimization which too often causes RETURN_VALUE to get # misclassified as RETURN_END_IF. Handle that here. # In RETURN_VALUE, JUMP_ABSOLUTE, RETURN_VALUE is never RETURN_END_IF if op == self.opc.RETURN_VALUE: if (offset+1 < len(code) and code[offset+1] == self.opc.JUMP_ABSOLUTE and offset in self.return_end_ifs): self.return_end_ifs.remove(offset) pass pass elif op == self.opc.JUMP_FORWARD: # If we have: # JUMP_FORWARD x, [non-jump, insns], RETURN_VALUE, x: # then RETURN_VALUE is not RETURN_END_IF rtarget = self.get_target(offset) rtarget_prev = self.prev[rtarget] if (code[rtarget_prev] == self.opc.RETURN_VALUE and rtarget_prev in self.return_end_ifs): i = rtarget_prev while i != offset: if code[i] in [op3.JUMP_FORWARD, op3.JUMP_ABSOLUTE]: return i = self.prev[i] self.return_end_ifs.remove(rtarget_prev) pass return def is_jump_back(self, offset): """ Return True if the code at offset is some sort of jump back. That is, it is ether "JUMP_FORWARD" or an absolute jump that goes forward. """ if self.code[offset] != self.opc.JUMP_ABSOLUTE: return False return offset > self.get_target(offset) def next_except_jump(self, start): """ Return the next jump that was generated by an except SomeException: construct in a try...except...else clause or None if not found. """ if self.code[start] == self.opc.DUP_TOP: except_match = self.first_instr(start, len(self.code), self.opc.POP_JUMP_IF_FALSE) if except_match: jmp = self.prev_op[self.get_target(except_match)] self.ignore_if.add(except_match) self.not_continue.add(jmp) return jmp count_END_FINALLY = 0 count_SETUP_ = 0 for i in self.op_range(start, len(self.code)): op = self.code[i] if op == self.opc.END_FINALLY: if count_END_FINALLY == count_SETUP_: assert self.code[self.prev_op[i]] in (JUMP_ABSOLUTE, JUMP_FORWARD, RETURN_VALUE) self.not_continue.add(self.prev_op[i]) return self.prev_op[i] count_END_FINALLY += 1 elif op in self.setup_opts_no_loop: count_SETUP_ += 1 def rem_or(self, start, end, instr, target=None, include_beyond_target=False): """ Find offsets of all requested between and , optionally ing specified offset, and return list found offsets which are not within any POP_JUMP_IF_TRUE jumps. """ assert(start>=0 and end<=len(self.code) and start <= end) # Find all offsets of requested instructions instr_offsets = self.all_instr(start, end, instr, target, include_beyond_target) # Get all POP_JUMP_IF_TRUE (or) offsets pjit_offsets = self.all_instr(start, end, self.opc.POP_JUMP_IF_TRUE) filtered = [] for pjit_offset in pjit_offsets: pjit_tgt = self.get_target(pjit_offset) - 3 for instr_offset in instr_offsets: if instr_offset <= pjit_offset or instr_offset >= pjit_tgt: filtered.append(instr_offset) instr_offsets = filtered filtered = [] return instr_offsets if __name__ == "__main__": from uncompyle6 import PYTHON_VERSION if PYTHON_VERSION >= 3.2: import inspect co = inspect.currentframe().f_code from uncompyle6 import PYTHON_VERSION tokens, customize = Scanner3(PYTHON_VERSION).ingest(co) for t in tokens: print(t) else: print("Need to be Python 3.2 or greater to demo; I am %s." % PYTHON_VERSION) pass