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python-uncompyle6/uncompyle6/scanners/scanner3.py
rocky 05db6194ec Use up right 3.x opcodes in jump detection... 
A small but pervasive, and I guess important change. More correct COME_FROMs
are now coming out. A number of grammar changes then in 3.0, 3.5, and 3.8
2019-04-23 05:14:29 -04:00

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# Copyright (c) 2015-2019 by Rocky Bernstein
# Copyright (c) 2005 by Dan Pascu <dan@windowmaker.org>
# Copyright (c) 2000-2002 by hartmut Goebel <h.goebel@crazy-compilers.com>
#
# 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 <http://www.gnu.org/licenses/>.
"""
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.code import iscode
from xdis.bytecode import instruction_size, _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
# Ops that start SETUP_ ... We will COME_FROM with these names
# 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:
# There is a an implied JUMP_IF_TRUE that we are not testing for (yet?) here
assert_can_follow = inst.opname == 'POP_TOP' and i+1 < n
else:
assert_can_follow = inst.opname == 'POP_JUMP_IF_TRUE' and i+1 < n
if assert_can_follow:
next_inst = self.insts[i+1]
if (next_inst.opname == 'LOAD_GLOBAL' and
next_inst.argval == 'AssertionError'):
if (i + 2 < n and self.insts[i+2].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 == '<lambda>':
assert opname == 'LOAD_CONST'
opname = 'LOAD_LAMBDA'
elif const.co_name == '<genexpr>':
opname = 'LOAD_GENEXPR'
elif const.co_name == '<dictcomp>':
opname = 'LOAD_DICTCOMP'
elif const.co_name == '<setcomp>':
opname = 'LOAD_SETCOMP'
elif const.co_name == '<listcomp>':
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 = '<code_object ' + const.co_name + '>'
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 pair, %d annotated" %
(pos_args, name_pair_args, annotate_args))
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)
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 == '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 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 (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='L.'))
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)
# 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
else:
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:
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
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 < 3.8 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 <instr> between <start> and <end>,
optionally <target>ing specified offset, and return list found
<instr> 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
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