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499 lines
21 KiB
Python
499 lines
21 KiB
Python
"""
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Python 3.2 bytecode scanner/deparser
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Copyright (c) 1999 John Aycock
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Copyright (c) 2000-2002 by hartmut Goebel <h.goebel@crazy-compilers.com>
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Copyright (c) 2005 by Dan Pascu <dan@windowmaker.org>
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Copyright (c) 2015 by Rocky Bernstein
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See main module for license.
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This overlaps Python's 3.2's dis module, but it can be run from
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Python3 and other versions of Python. Also, we save token information
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for later use in deparsing.
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"""
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from __future__ import print_function
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import dis, marshal
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from collections import namedtuple
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from uncompyle6.scanner import Token, L65536
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# Get all the opcodes into globals
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globals().update(dis.opmap)
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from uncompyle6.opcodes.opcode_27 import *
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import uncompyle6.scanner as scan
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class Scanner32(scan.Scanner):
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def __init__(self):
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self.Token = scan.Scanner.__init__(self, 3.2) # check
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def run(self, bytecode):
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code_object = marshal.loads(bytecode)
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tokens = self.tokenize(code_object)
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return tokens
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def disassemble(self, co):
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"""
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Convert code object <co> into a sequence of tokens.
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Based on dis.disassemble() function.
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"""
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# Container for tokens
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tokens = []
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customize = {}
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self.code = code = co.co_code
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codelen = len(code)
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self.build_lines_data(co)
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self.build_prev_op()
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# Get jump targets
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# Format: {target offset: [jump offsets]}
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jump_targets = self.find_jump_targets()
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# Initialize extended arg at 0. When extended arg op is encountered,
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# variable preserved for next cycle and added as arg for next op
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extended_arg = 0
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free = None
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for offset in self.op_range(0, codelen):
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# Add jump target tokens
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if offset in jump_targets:
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jump_idx = 0
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for jump_offset in jump_targets[offset]:
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tokens.append(Token('COME_FROM', None, repr(jump_offset),
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offset='{}_{}'.format(offset, jump_idx)))
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jump_idx += 1
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op = code[offset]
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# Create token and fill all the fields we can
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# w/o touching arguments
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current_token = Token(dis.opname[op])
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current_token.offset = offset
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if offset in self.linestarts:
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current_token.linestart = self.linestarts[offset]
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else:
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current_token.linestart = None
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if op >= dis.HAVE_ARGUMENT:
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# Calculate op's argument value based on its argument and
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# preceding extended argument, if any
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oparg = code[offset+1] + code[offset+2]*256 + extended_arg
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extended_arg = 0
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if op == dis.EXTENDED_ARG:
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extended_arg = oparg * L65536
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# Fill token's attr/pattr fields
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current_token.attr = oparg
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if op in dis.hasconst:
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current_token.pattr = repr(co.co_consts[oparg])
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elif op in dis.hasname:
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current_token.pattr = co.co_names[oparg]
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elif op in dis.hasjrel:
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current_token.pattr = repr(offset + 3 + oparg)
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elif op in dis.haslocal:
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current_token.pattr = co.co_varnames[oparg]
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elif op in dis.hascompare:
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current_token.pattr = dis.cmp_op[oparg]
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elif op in dis.hasfree:
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if free is None:
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free = co.co_cellvars + co.co_freevars
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current_token.pattr = free[oparg]
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tokens.append(current_token)
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return tokens, customize
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def build_lines_data(self, code_obj):
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"""
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Generate various line-related helper data.
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"""
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# Offset: lineno pairs, only for offsets which start line.
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# Locally we use list for more convenient iteration using indices
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linestarts = list(dis.findlinestarts(code_obj))
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self.linestarts = dict(linestarts)
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# Plain set with offsets of first ops on line
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self.linestart_offsets = {a for (a, _) in linestarts}
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# 'List-map' which shows line number of current op and offset of
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# first op on following line, given offset of op as index
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self.lines = lines = []
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LineTuple = namedtuple('LineTuple', ['l_no', 'next'])
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# Iterate through available linestarts, and fill
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# the data for all code offsets encountered until
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# last linestart offset
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_, prev_line_no = linestarts[0]
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offset = 0
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for start_offset, line_no in linestarts[1:]:
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while offset < start_offset:
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lines.append(LineTuple(prev_line_no, start_offset))
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offset += 1
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prev_line_no = line_no
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# Fill remaining offsets with reference to last line number
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# and code length as start offset of following non-existing line
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codelen = len(self.code)
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while offset < codelen:
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lines.append(LineTuple(prev_line_no, codelen))
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offset += 1
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def build_prev_op(self):
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"""
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Compose 'list-map' which allows to jump to previous
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op, given offset of current op as index.
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"""
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code = self.code
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codelen = len(code)
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self.prev_op = [0]
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for offset in self.op_range(0, codelen):
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op = code[offset]
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for _ in range(self.op_size(op)):
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self.prev_op.append(offset)
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def op_size(self, op):
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"""
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Return size of operator with its arguments
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for given opcode <op>.
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"""
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if op < dis.HAVE_ARGUMENT:
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return 1
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else:
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return 3
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def find_jump_targets(self):
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"""
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Detect all offsets in a byte code which are jump targets.
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Return the list of offsets.
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This procedure is modelled after dis.findlables(), but here
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for each target the number of jumps is counted.
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"""
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code = self.code
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codelen = len(code)
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self.structs = [{'type': 'root',
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'start': 0,
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'end': codelen-1}]
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# All loop entry points
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# self.loops = []
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# Map fixed jumps to their real destination
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self.fixed_jumps = {}
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self.ignore_if = set()
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self.build_statement_indices()
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# Containers filled by detect_structure()
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self.not_continue = set()
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self.return_end_ifs = set()
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targets = {}
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for offset in self.op_range(0, codelen):
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op = code[offset]
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# Determine structures and fix jumps for 2.3+
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self.detect_structure(offset)
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if op >= dis.HAVE_ARGUMENT:
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label = self.fixed_jumps.get(offset)
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oparg = code[offset+1] + code[offset+2] * 256
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if label is None:
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if op in dis.hasjrel and op != FOR_ITER:
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label = offset + 3 + oparg
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elif op in dis.hasjabs:
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if op in (JUMP_IF_FALSE_OR_POP, JUMP_IF_TRUE_OR_POP):
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if oparg > offset:
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label = oparg
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if label is not None and label != -1:
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targets[label] = targets.get(label, []) + [offset]
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elif op == END_FINALLY and offset in self.fixed_jumps:
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label = self.fixed_jumps[offset]
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targets[label] = targets.get(label, []) + [offset]
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return targets
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def build_statement_indices(self):
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code = self.code
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start = 0
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end = codelen = len(code)
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statement_opcodes = {
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SETUP_LOOP, BREAK_LOOP, CONTINUE_LOOP,
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SETUP_FINALLY, END_FINALLY, SETUP_EXCEPT, SETUP_WITH,
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POP_BLOCK, STORE_FAST, DELETE_FAST, STORE_DEREF,
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STORE_GLOBAL, DELETE_GLOBAL, STORE_NAME, DELETE_NAME,
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STORE_ATTR, DELETE_ATTR, STORE_SUBSCR, DELETE_SUBSCR,
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RETURN_VALUE, RAISE_VARARGS, POP_TOP, PRINT_EXPR,
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JUMP_ABSOLUTE
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}
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statement_opcode_sequences = [(POP_JUMP_IF_FALSE, JUMP_FORWARD), (POP_JUMP_IF_FALSE, JUMP_ABSOLUTE),
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(POP_JUMP_IF_TRUE, JUMP_FORWARD), (POP_JUMP_IF_TRUE, JUMP_ABSOLUTE)]
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designator_ops = {
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STORE_FAST, STORE_NAME, STORE_GLOBAL, STORE_DEREF, STORE_ATTR,
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STORE_SUBSCR, UNPACK_SEQUENCE, JUMP_ABSOLUTE
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}
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# Compose preliminary list of indices with statements,
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# using plain statement opcodes
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prelim = self.all_instr(start, end, statement_opcodes)
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# Initialize final container with statements with
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# preliminnary data
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stmts = self.stmts = set(prelim)
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# Same for opcode sequences
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pass_stmts = set()
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for sequence in statement_opcode_sequences:
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for i in self.op_range(start, end-(len(sequence)+1)):
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match = True
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for elem in sequence:
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if elem != code[i]:
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match = False
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break
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i += self.op_size(code[i])
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if match is True:
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i = self.prev_op[i]
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stmts.add(i)
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pass_stmts.add(i)
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# Initialize statement list with the full data we've gathered so far
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if pass_stmts:
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stmt_offset_list = list(stmts)
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stmt_offset_list.sort()
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else:
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stmt_offset_list = prelim
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# 'List-map' which contains offset of start of
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# next statement, when op offset is passed as index
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self.next_stmt = slist = []
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last_stmt_offset = -1
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i = 0
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# Go through all statement offsets
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for stmt_offset in stmt_offset_list:
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# Process absolute jumps, but do not remove 'pass' statements
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# from the set
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if code[stmt_offset] == JUMP_ABSOLUTE and stmt_offset not in pass_stmts:
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# If absolute jump occurs in forward direction or it takes off from the
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# same line as previous statement, this is not a statement
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target = self.get_target(stmt_offset)
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if target > stmt_offset or self.lines[last_stmt_offset].l_no == self.lines[stmt_offset].l_no:
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stmts.remove(stmt_offset)
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continue
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# Rewing ops till we encounter non-JA one
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j = self.prev_op[stmt_offset]
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while code[j] == JUMP_ABSOLUTE:
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j = self.prev_op[j]
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# If we got here, then it's list comprehension which
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# is not a statement too
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if code[j] == LIST_APPEND:
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stmts.remove(stmt_offset)
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continue
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# Exclude ROT_TWO + POP_TOP
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elif code[stmt_offset] == POP_TOP and code[self.prev_op[stmt_offset]] == ROT_TWO:
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stmts.remove(stmt_offset)
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continue
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# Exclude FOR_ITER + designators
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elif code[stmt_offset] in designator_ops:
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j = self.prev_op[stmt_offset]
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while code[j] in designator_ops:
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j = self.prev_op[j]
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if code[j] == FOR_ITER:
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stmts.remove(stmt_offset)
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continue
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# Add to list another list with offset of current statement,
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# equal to length of previous statement
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slist += [stmt_offset] * (stmt_offset-i)
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last_stmt_offset = stmt_offset
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i = stmt_offset
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# Finish filling the list for last statement
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slist += [codelen] * (codelen-len(slist))
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def get_target(self, offset):
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"""
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Get target offset for op located at given <offset>.
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"""
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op = self.code[offset]
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target = self.code[offset+1] + self.code[offset+2] * 256
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if op in dis.hasjrel:
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target += offset + 3
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return target
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def detect_structure(self, offset):
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"""
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Detect structures and their boundaries to fix optimizied jumps
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in python2.3+
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"""
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code = self.code
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op = code[offset]
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# Detect parent structure
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parent = self.structs[0]
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start = parent['start']
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end = parent['end']
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# Pick inner-most parent for our offset
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for struct in self.structs:
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curent_start = struct['start']
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curent_end = struct['end']
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if (curent_start <= offset < curent_end) and (curent_start >= start and curent_end <= end):
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start = curent_start
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end = curent_end
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parent = struct
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if op in (POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE):
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start = offset + self.op_size(op)
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target = self.get_target(offset)
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rtarget = self.restrict_to_parent(target, parent)
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prev_op = self.prev_op
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# Do not let jump to go out of parent struct bounds
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if target != rtarget and parent['type'] == 'and/or':
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self.fixed_jumps[offset] = rtarget
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return
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# Does this jump to right after another cond jump?
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# If so, it's part of a larger conditional
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if (code[prev_op[target]] in (JUMP_IF_FALSE_OR_POP, JUMP_IF_TRUE_OR_POP,
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POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE)) and (target > offset):
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self.fixed_jumps[offset] = prev_op[target]
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self.structs.append({'type': 'and/or',
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'start': start,
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'end': prev_op[target]})
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return
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# Is it an and inside if block
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if op == POP_JUMP_IF_FALSE:
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# Search for other POP_JUMP_IF_FALSE targetting the same op,
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# in current statement, starting from current offset, and filter
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# everything inside inner 'or' jumps and midline ifs
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match = self.rem_or(start, self.next_stmt[offset], POP_JUMP_IF_FALSE, target)
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match = self.remove_mid_line_ifs(match)
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# If we still have any offsets in set, start working on it
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if match:
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if (code[prev_op[rtarget]] in (JUMP_FORWARD, JUMP_ABSOLUTE) and prev_op[rtarget] not in self.stmts and
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self.restrict_to_parent(self.get_target(prev_op[rtarget]), parent) == rtarget):
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if (code[prev_op[prev_op[rtarget]]] == JUMP_ABSOLUTE and self.remove_mid_line_ifs([offset]) and
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target == self.get_target(prev_op[prev_op[rtarget]]) and
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(prev_op[prev_op[rtarget]] not in self.stmts or self.get_target(prev_op[prev_op[rtarget]]) > prev_op[prev_op[rtarget]]) and
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1 == len(self.remove_mid_line_ifs(self.rem_or(start, prev_op[prev_op[rtarget]], (POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE), target)))):
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pass
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elif (code[prev_op[prev_op[rtarget]]] == RETURN_VALUE and self.remove_mid_line_ifs([offset]) and
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1 == (len(set(self.remove_mid_line_ifs(self.rem_or(start, prev_op[prev_op[rtarget]],
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(POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE), target))) |
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set(self.remove_mid_line_ifs(self.rem_or(start, prev_op[prev_op[rtarget]],
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(POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE, JUMP_ABSOLUTE),
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prev_op[rtarget], True)))))):
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pass
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else:
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fix = None
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jump_ifs = self.all_instr(start, self.next_stmt[offset], POP_JUMP_IF_FALSE)
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last_jump_good = True
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for j in jump_ifs:
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if target == self.get_target(j):
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if self.lines[j].next == j + 3 and last_jump_good:
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fix = j
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break
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else:
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last_jump_good = False
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self.fixed_jumps[offset] = fix or match[-1]
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return
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else:
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self.fixed_jumps[offset] = match[-1]
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return
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# op == POP_JUMP_IF_TRUE
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else:
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next = self.next_stmt[offset]
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if prev_op[next] == offset:
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pass
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elif code[next] in (JUMP_FORWARD, JUMP_ABSOLUTE) and target == self.get_target(next):
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if code[prev_op[next]] == POP_JUMP_IF_FALSE:
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if code[next] == JUMP_FORWARD or target != rtarget or code[prev_op[prev_op[rtarget]]] not in (JUMP_ABSOLUTE, RETURN_VALUE):
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self.fixed_jumps[offset] = prev_op[next]
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return
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elif (code[next] == JUMP_ABSOLUTE and code[target] in (JUMP_ABSOLUTE, JUMP_FORWARD) and
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self.get_target(target) == self.get_target(next)):
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self.fixed_jumps[offset] = prev_op[next]
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return
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# Don't add a struct for a while test, it's already taken care of
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if offset in self.ignore_if:
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return
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if (code[prev_op[rtarget]] == JUMP_ABSOLUTE and prev_op[rtarget] in self.stmts and
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prev_op[rtarget] != offset and prev_op[prev_op[rtarget]] != offset and
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not (code[rtarget] == JUMP_ABSOLUTE and code[rtarget+3] == POP_BLOCK and code[prev_op[prev_op[rtarget]]] != JUMP_ABSOLUTE)):
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rtarget = prev_op[rtarget]
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# Does the if jump just beyond a jump op, then this is probably an if statement
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if code[prev_op[rtarget]] in (JUMP_ABSOLUTE, JUMP_FORWARD):
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if_end = self.get_target(prev_op[rtarget])
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# Is this a loop not an if?
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if (if_end < prev_op[rtarget]) and (code[prev_op[if_end]] == SETUP_LOOP):
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if(if_end > start):
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return
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end = self.restrict_to_parent(if_end, parent)
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self.structs.append({'type': 'if-then',
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'start': start,
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'end': prev_op[rtarget]})
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self.not_continue.add(prev_op[rtarget])
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if rtarget < end:
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self.structs.append({'type': 'if-else',
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'start': rtarget,
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'end': end})
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elif code[prev_op[rtarget]] == RETURN_VALUE:
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self.structs.append({'type': 'if-then',
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'start': start,
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'end': rtarget})
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self.return_end_ifs.add(prev_op[rtarget])
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elif op in (JUMP_IF_FALSE_OR_POP, JUMP_IF_TRUE_OR_POP):
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target = self.get_target(offset)
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if target > offset:
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unop_target = self.last_instr(offset, target, JUMP_FORWARD, target)
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if unop_target and code[unop_target+3] != ROT_TWO:
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self.fixed_jumps[offset] = unop_target
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else:
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self.fixed_jumps[offset] = self.restrict_to_parent(target, parent)
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def restrict_to_parent(self, target, parent):
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"""Restrict target to parent structure boundaries."""
|
|
if not (parent['start'] < target < parent['end']):
|
|
target = parent['end']
|
|
return target
|
|
|
|
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.
|
|
"""
|
|
# 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, 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
|
|
|
|
def remove_mid_line_ifs(self, ifs):
|
|
"""
|
|
Go through passed offsets, filtering ifs
|
|
located somewhere mid-line.
|
|
"""
|
|
filtered = []
|
|
for if_ in ifs:
|
|
# For each offset, if line number of current and next op
|
|
# is the same
|
|
if self.lines[if_].l_no == self.lines[if_+3].l_no:
|
|
# Check if last op on line is PJIT or PJIF, and if it is - skip it
|
|
if self.code[self.prev_op[self.lines[if_].next]] in (POP_JUMP_IF_TRUE, POP_JUMP_IF_FALSE):
|
|
continue
|
|
filtered.append(if_)
|
|
return filtered
|