# Copyright (c) 2015-2019 by Rocky Bernstein # Copyright (c) 2005 by Dan Pascu # Copyright (c) 2000-2002 by hartmut Goebel # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . """ 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 xdis import iscode, instruction_size from xdis.bytecode import _get_const_info from uncompyle6.scanner import Token, parse_fn_counts import xdis # Get all the opcodes into globals import xdis.opcodes.opcode_33 as op3 from uncompyle6.scanner import Scanner import sys from uncompyle6 import PYTHON3 if PYTHON3: intern = sys.intern globals().update(op3.opmap) 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 # For ops that start SETUP_ ... we will add COME_FROM with these names # at the their targets. # Some blocks and END_ statements. And they can start # a new statement if self.version < 3.8: setup_ops = [ self.opc.SETUP_LOOP, self.opc.SETUP_EXCEPT, self.opc.SETUP_FINALLY, ] self.setup_ops_no_loop = frozenset(setup_ops) - frozenset( [self.opc.SETUP_LOOP] ) else: setup_ops = [self.opc.SETUP_FINALLY] self.setup_ops_no_loop = frozenset(setup_ops) if self.version >= 3.2: setup_ops.append(self.opc.SETUP_WITH) self.setup_ops = frozenset(setup_ops) if self.version == 3.0: self.pop_jump_tf = frozenset( [self.opc.JUMP_IF_FALSE, self.opc.JUMP_IF_TRUE] ) self.not_continue_follow = ("END_FINALLY", "POP_BLOCK", "POP_TOP") else: self.pop_jump_tf = frozenset([self.opc.PJIF, self.opc.PJIT]) self.not_continue_follow = ("END_FINALLY", "POP_BLOCK") # Opcodes that can start a statement. statement_opcodes = [ 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, ] if self.version < 3.8: statement_opcodes += [self.opc.BREAK_LOOP, self.opc.CONTINUE_LOOP] self.statement_opcodes = frozenset(statement_opcodes) | self.setup_ops_no_loop # Opcodes that can start a "store" 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,), ] # FIXME: remove this and use instead info from xdis. # 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 or self.version >= 3.7: varargs_ops.add(self.opc.CALL_METHOD) if self.version >= 3.5: varargs_ops |= set( [ self.opc.BUILD_SET_UNPACK, self.opc.BUILD_MAP_UNPACK, # we will handle this later self.opc.BUILD_LIST_UNPACK, self.opc.BUILD_TUPLE_UNPACK, ] ) if self.version >= 3.6: varargs_ops.add(self.opc.BUILD_CONST_KEY_MAP) # Below is in bit order, "default = bit 0, closure = bit 3 self.MAKE_FUNCTION_FLAGS = tuple( """ default keyword-only annotation closure""".split() ) self.varargs_ops = frozenset(varargs_ops) # FIXME: remove the above in favor of: # self.varargs_ops = frozenset(self.opc.hasvargs) return 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 - some EXTENDED_ARGS instructions are removed 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. """ if not show_asm: show_asm = self.show_asm bytecode = self.build_instructions(co) # show_asm = 'both' if show_asm in ("both", "before"): for instr in bytecode.get_instructions(co): print(instr.disassemble()) # list of tokens/instructions tokens = [] # "customize" is in the process of going away here customize = {} if self.is_pypy: customize["PyPy"] = 0 # Scan for assertions. Later we will # turn 'LOAD_GLOBAL' to 'LOAD_ASSERT'. # 'LOAD_ASSERT' is used in assert statements. self.load_asserts = set() n = len(self.insts) for i, inst in enumerate(self.insts): # 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 self.version == 3.0: # Like 2.6, 3.0 doesn't have POP_JUMP_IF... so we have # to go through more machinations assert_can_follow = inst.opname == "POP_TOP" and i + 1 < n if assert_can_follow: prev_inst = self.insts[i - 1] assert_can_follow = ( prev_inst.opname in ("JUMP_IF_TRUE", "JUMP_IF_FALSE") and i + 1 < n ) jump_if_inst = prev_inst else: assert_can_follow = ( inst.opname in ("POP_JUMP_IF_TRUE", "POP_JUMP_IF_FALSE") and i + 1 < n ) jump_if_inst = inst if assert_can_follow: next_inst = self.insts[i + 1] if ( next_inst.opname == "LOAD_GLOBAL" and next_inst.argval == "AssertionError" and jump_if_inst.argval ): raise_idx = self.offset2inst_index[self.prev_op[jump_if_inst.argval]] raise_inst = self.insts[raise_idx] if raise_inst.opname.startswith("RAISE_VARARGS"): self.load_asserts.add(next_inst.offset) pass pass # Get jump targets # Format: {target offset: [jump offsets]} jump_targets = self.find_jump_targets(show_asm) # print("XXX2", jump_targets) last_op_was_break = False for i, inst in enumerate(self.insts): argval = inst.argval op = inst.opcode if inst.opname == "EXTENDED_ARG": # FIXME: The EXTENDED_ARG is used to signal annotation # parameters if i + 1 < n and self.insts[i + 1].opcode != self.opc.MAKE_FUNCTION: continue 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_for_offset(jump_offset) if opname == "EXTENDED_ARG": j = xdis.next_offset(op, self.opc, jump_offset) opname = self.opname_for_offset(j) if opname.startswith("SETUP_"): come_from_type = opname[len("SETUP_") :] come_from_name = "COME_FROM_%s" % come_from_type pass elif inst.offset in self.except_targets: come_from_name = "COME_FROM_EXCEPT_CLAUSE" tokens.append( Token( come_from_name, jump_offset, 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 if op in self.opc.CONST_OPS: const = argval if iscode(const): if const.co_name == "": assert opname == "LOAD_CONST" 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" else: opname = "LOAD_CODE" # 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 = "" elif isinstance(const, str) or xdis.PYTHON_VERSION <= 2.7 and isinstance(const, unicode): opname = "LOAD_STR" else: if isinstance(inst.arg, int) and inst.arg < len(co.co_consts): argval, _ = _get_const_info(inst.arg, co.co_consts) # Why don't we use _ above for "pattr" rather than "const"? # This *is* a little hoaky, but we have to coordinate with # other parts like n_LOAD_CONST in pysource.py for example. pattr = const pass elif opname in ("MAKE_FUNCTION", "MAKE_CLOSURE"): if self.version >= 3.6: # 3.6+ doesn't have MAKE_CLOSURE, so opname == 'MAKE_FUNCTION' flags = argval opname = "MAKE_FUNCTION_%d" % (flags) attr = [] for flag in self.MAKE_FUNCTION_FLAGS: bit = flags & 1 attr.append(bit) flags >>= 1 attr = attr[:4] # remove last value: attr[5] == False else: pos_args, name_pair_args, annotate_args = parse_fn_counts( inst.argval ) pattr = "%d positional, %d keyword only, %d annotated" % ( pos_args, name_pair_args, annotate_args, ) if name_pair_args > 0: # FIXME: this should probably be K_ 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) attr = (pos_args, name_pair_args, annotate_args) tokens.append( Token( opname=opname, attr=attr, pattr=pattr, offset=inst.offset, linestart=inst.starts_line, op=op, has_arg=inst.has_arg, opc=self.opc, ) ) continue elif op in self.varargs_ops: pos_args = 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 ("JUMP_IF_NOT_DEBUG", "CALL_FUNCTION"): if opname == "JUMP_IF_NOT_DEBUG": # The value in the dict is in special cases in semantic actions, such # as JUMP_IF_NOT_DEBUG. The value is not used in these cases, so we put # in arbitrary value 0. customize[opname] = 0 elif self.version >= 3.6 and argval > 255: opname = "CALL_FUNCTION_KW" pass elif opname == "UNPACK_EX": # FIXME: try with scanner and parser by # changing argval before_args = argval & 0xFF after_args = (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 = argval target = self.get_target(inst.offset) if target <= inst.offset: next_opname = self.insts[i + 1].opname # 'Continue's include jumps to loops that are not # and the end of a block which follow with POP_BLOCK and COME_FROM_LOOP. # If the JUMP_ABSOLUTE is to a FOR_ITER and it is followed by another JUMP_FORWARD # then we'll take it as a "continue". is_continue = ( self.insts[self.offset2inst_index[target]].opname == "FOR_ITER" and self.insts[i + 1].opname == "JUMP_FORWARD" ) if (self.version == 3.0 and self.insts[i + 1].opname == "JUMP_FORWARD" and not is_continue): target_prev = self.offset2inst_index[self.prev_op[target]] is_continue = ( self.insts[target_prev].opname == "SETUP_LOOP") if is_continue or ( inst.offset in self.stmts and ( inst.starts_line and next_opname not in self.not_continue_follow ) ): opname = "CONTINUE" 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].kind == "JUMP_BACK" and tokens[-1].attr <= argval: if tokens[-2].kind == "BREAK_LOOP": del tokens[-1] else: # intern is used because we are changing the *previous* token tokens[-1].kind = intern("CONTINUE") if last_op_was_break and opname == "CONTINUE": last_op_was_break = False continue # FIXME: go over for Python 3.6+. This is sometimes wrong 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( opname=opname, attr=argval, pattr=pattr, offset=inst.offset, linestart=inst.starts_line, op=op, has_arg=inst.has_arg, opc=self.opc, ) ) pass if show_asm in ("both", "after"): for t in tokens: print(t.format(line_prefix="")) print() return tokens, customize 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.except_targets = {} 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 i, inst in enumerate(self.insts): offset = inst.offset op = inst.opcode # Determine structures and fix jumps in Python versions # since 2.3 self.detect_control_flow(offset, targets, i) if inst.has_arg: label = self.fixed_jumps.get(offset) oparg = inst.arg if self.version >= 3.6 and self.code[offset] == self.opc.EXTENDED_ARG: j = xdis.next_offset(op, self.opc, offset) next_offset = xdis.next_offset(op, self.opc, j) else: next_offset = xdis.next_offset(op, self.opc, offset) if label is None: if op in self.opc.hasjrel and op != self.opc.FOR_ITER: label = next_offset + oparg elif op in self.opc.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 # for loop # 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.inst_matches(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 += instruction_size(code[i], self.opc) 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 # FIXME: 0 isn't always correct 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 detect_control_flow(self, offset, targets, inst_index): """ Detect type of block structures and their boundaries to fix optimized jumps in python2.3+ """ code = self.code inst = self.insts[inst_index] op = inst.opcode # 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 self.version < 3.8 and 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. start += inst.inst_size target = self.get_target(offset) end = self.restrict_to_parent(target, parent) 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 = xdis.next_offset( code[jump_back], self.opc, jump_back ) 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: # loop suite ends in return jump_back = self.last_instr(start, end, self.opc.RETURN_VALUE) if not jump_back: return jb_inst = self.get_inst(jump_back) jump_back = self.next_offset(jb_inst.opcode, jump_back) if_offset = None if code[self.prev_op[next_line_byte]] not in self.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 = xdis.next_offset(code[jump_back], self.opc, jump_back) else: if self.get_target(jump_back) >= next_line_byte: jump_back = self.last_instr( start, end, self.opc.JUMP_ABSOLUTE, start, False ) jb_inst = self.get_inst(jump_back) jb_next_offset = self.next_offset(jb_inst.opcode, jump_back) if end > jb_next_offset and self.is_jump_forward(end): if self.is_jump_forward(jb_next_offset): if self.get_target(jb_next_offset) == self.get_target(end): self.fixed_jumps[offset] = jb_next_offset end = jb_next_offset elif target < offset: self.fixed_jumps[offset] = jb_next_offset end = jb_next_offset 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 self.opc.JUMP_OPs: 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} ) after_jump_offset = xdis.next_offset(code[jump_back], self.opc, jump_back) if after_jump_offset != end: self.structs.append( { "type": loop_type + "-else", "start": after_jump_offset, "end": end, } ) elif op in self.pop_jump_tf: start = offset + inst.inst_size target = inst.argval 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. pretarget = self.get_inst(prev_op[target]) if ( pretarget.opcode in self.pop_jump_if_pop and (target > offset) and pretarget.offset != offset ): # FIXME: hack upon hack... # In some cases the pretarget can be a jump to the next instruction # and these aren't and/or's either. We limit to 3.5+ since we experienced there # but it might be earlier versions, or might be a general principle. if self.version < 3.5 or pretarget.argval != target: # FIXME: this is not accurate The commented out below # is what it should be. However grammar rules right now # assume the incorrect offsets. # self.fixed_jumps[offset] = target self.fixed_jumps[offset] = pretarget.offset self.structs.append( {"type": "and/or", "start": start, "end": pretarget.offset} ) return # The opcode *two* instructions 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 ) # FIXME: Remove this whole "if" block # 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], self.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], self.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 elif self.version <= 3.2: fix = None jump_ifs = self.inst_matches( 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): # FIXME: remove magic number 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: if self.version < 3.6: # FIXME: this is putting in COME_FROMs in the wrong place. # Fix up grammar so we don't need to do this. # See cf_for_iter use in parser36.py self.fixed_jumps[offset] = match[-1] elif target > offset: # Right now we only add COME_FROMs in forward (not loop) jumps self.fixed_jumps[offset] = target 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 rtarget_is_ja = code[pre_rtarget] == self.opc.JUMP_ABSOLUTE if ( rtarget_is_ja 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 # # For 3.5, in addition the JUMP_FORWARD above we could have # JUMP_BACK or CONTINUE # # There are other situations we may need to consider, like # if the condition jump is to a forward location. # Also the existence of a jump to the instruction after "END_FINALLY" # will distinguish "try/else" from "try". if self.version < 3.8: rtarget_break = (self.opc.RETURN_VALUE, self.opc.BREAK_LOOP) else: rtarget_break = (self.opc.RETURN_VALUE,) if self.is_jump_forward(pre_rtarget) or ( rtarget_is_ja and self.version >= 3.5 ): if_end = self.get_target(pre_rtarget) # If the jump target is back, we are looping if ( if_end < pre_rtarget and self.version < 3.8 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} ) # FIXME: add this # self.fixed_jumps[offset] = 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, 0): 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 rtarget_break: 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 self.version < 3.6 and 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 += instruction_size(self.code[next_op], self.opc) if code[next_op] == self.opc.JUMP_ABSOLUTE: next_op += instruction_size(self.code[next_op], self.opc) if next_op in targets: for try_op in targets[next_op]: come_from_op = code[try_op] if ( self.version < 3.8 and come_from_op == self.opc.SETUP_EXCEPT ): return pass pass if self.version >= 3.4: self.fixed_jumps[offset] = rtarget if code[pre_rtarget] == self.opc.RETURN_VALUE: # If we are at some sort of POP_JUMP_IF and the instruction before was # COMPARE_OP exception-match, then pre_rtarget is not an end_if if not ( inst_index > 0 and self.insts[inst_index - 1].argval == "exception-match" ): self.return_end_ifs.add(pre_rtarget) else: self.fixed_jumps[offset] = rtarget self.not_continue.add(pre_rtarget) else: # FIXME: this is very convoluted and based on rather hacky # empirical evidence. It should go a way when # we have better control-flow analysis normal_jump = self.version >= 3.6 if self.version == 3.5: j = self.offset2inst_index[target] if j + 2 < len(self.insts) and self.insts[j + 2].is_jump_target: normal_jump = self.insts[j + 1].opname == "POP_BLOCK" if normal_jump: # For now, we'll only tag forward jump. if target > offset: self.fixed_jumps[offset] = target pass else: # FIXME: This is probably a bug in < 3.5 and we should # instead use the above code. But until we smoke things # out we'll stick with it. if rtarget > offset: self.fixed_jumps[offset] = rtarget elif self.version < 3.8 and 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.POP_EXCEPT: next_offset = xdis.next_offset(op, self.opc, offset) target = self.get_target(next_offset) if target > next_offset: next_op = code[next_offset] if ( self.opc.JUMP_ABSOLUTE == next_op and self.opc.END_FINALLY != code[xdis.next_offset(next_op, self.opc, next_offset)] ): self.fixed_jumps[next_offset] = target self.except_targets[target] = next_offset 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: next_offset = xdis.next_offset(op, self.opc, offset) if next_offset < len(code) and ( code[next_offset] == 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, extended_arg): """ 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, extended_arg) 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 frozenset( [ self.opc.JUMP_ABSOLUTE, self.opc.JUMP_FORWARD, self.opc.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.inst_matches( start, end, instr, target, include_beyond_target ) # Get all POP_JUMP_IF_TRUE (or) offsets if self.version == 3.0: jump_true_op = self.opc.JUMP_IF_TRUE else: jump_true_op = self.opc.POP_JUMP_IF_TRUE pjit_offsets = self.inst_matches(start, end, jump_true_op) 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