mirror of
https://github.com/CPunch/LuaDecompy.git
synced 2025-02-03 05:50:08 +00:00
Inital commit
- Extremely basic decompiler implemented in lparser.py - lundump.py ported from [this repository](https://github.com/CPunch/LuaPytecode)
This commit is contained in:
213
lparser.py
Normal file
213
lparser.py
Normal file
@@ -0,0 +1,213 @@
|
||||
'''
|
||||
lparser.py
|
||||
|
||||
Depends on ldump.py for lua dump deserialization.
|
||||
|
||||
An experimental bytecode decompiler.
|
||||
'''
|
||||
|
||||
from operator import concat
|
||||
from subprocess import call
|
||||
from lundump import Chunk, LuaUndump, Constant, Instruction, InstructionType, Opcodes
|
||||
|
||||
class _Scope:
|
||||
def __init__(self, startPC: int, endPC: int):
|
||||
self.startPC = startPC
|
||||
self.endPC = endPC
|
||||
|
||||
class LuaDecomp:
|
||||
def __init__(self, chunk: Chunk):
|
||||
self.chunk = chunk
|
||||
self.pc = 0
|
||||
self.scope = []
|
||||
self.top = {}
|
||||
self.locals = {}
|
||||
self.unknownLocalCount = 0
|
||||
self.src: str = ""
|
||||
|
||||
# configurations!
|
||||
self.aggressiveLocals = False # should *EVERY* accessed register be considered a local?
|
||||
self.indexWidth = 4 # how many spaces for indentions?
|
||||
|
||||
# parse instructions
|
||||
while self.pc < len(self.chunk.instructions):
|
||||
self.parseExpr()
|
||||
self.pc += 1
|
||||
|
||||
# end the scope (if we're supposed too)
|
||||
self.__checkScope()
|
||||
|
||||
print("\n==== [[" + str(self.chunk.name) + "'s decompiled source]] ====\n")
|
||||
print(self.src)
|
||||
|
||||
def __makeLocalIdentifier(self, indx: int) -> str:
|
||||
self.locals[indx] = "__unknLocal%d" % self.unknownLocalCount
|
||||
self.unknownLocalCount += 1
|
||||
|
||||
return self.locals[indx]
|
||||
|
||||
def __newLocal(self, indx: int, expr: str) -> None:
|
||||
# TODO: grab identifier from chunk(?)
|
||||
self.__makeLocalIdentifier(indx)
|
||||
|
||||
self.__startStatement()
|
||||
self.__addExpr("local " + self.locals[indx] + " = " + expr)
|
||||
|
||||
def __getNextInstr(self) -> Instruction:
|
||||
if self.pc + 1 < len(self.chunk.instructions):
|
||||
return self.chunk.instructions[self.pc + 1]
|
||||
|
||||
return None
|
||||
|
||||
def __getCurrInstr(self) -> Instruction:
|
||||
return self.chunk.instructions[self.pc]
|
||||
|
||||
def __addExpr(self, code: str) -> None:
|
||||
self.src += code
|
||||
|
||||
def __startStatement(self):
|
||||
self.src += '\n' + (' ' * self.indexWidth * len(self.scope))
|
||||
|
||||
def __getReg(self, indx: int) -> str:
|
||||
# if the top indx is a local, get it
|
||||
return self.locals[indx] if indx in self.locals else self.top[indx]
|
||||
|
||||
def __setReg(self, indx: int, code: str) -> None:
|
||||
# if the top indx is a local, set it
|
||||
if indx in self.locals:
|
||||
self.__startStatement()
|
||||
self.__addExpr(self.locals[indx] + " = " + code)
|
||||
elif self.aggressiveLocals: # 'every register is a local!!'
|
||||
self.__newLocal(indx, code)
|
||||
|
||||
self.top[indx] = code
|
||||
|
||||
def __startScope(self, scopeType: str, size: int) -> None:
|
||||
self.__addExpr(scopeType)
|
||||
self.scope.append(_Scope(self.pc, self.pc + size))
|
||||
|
||||
# checks if we need to end a scope
|
||||
def __checkScope(self) -> None:
|
||||
if len(self.scope) == 0:
|
||||
return
|
||||
|
||||
if self.pc > self.scope[len(self.scope) - 1].endPC:
|
||||
self.__endScope()
|
||||
|
||||
def __endScope(self) -> None:
|
||||
self.scope.pop()
|
||||
self.__startStatement()
|
||||
self.__addExpr("end")
|
||||
|
||||
def __emitOperand(self, a: int, b: str, c: str, op: str) -> None:
|
||||
self.__setReg(a, "(" + b + op + c + ")")
|
||||
|
||||
# 'RK's are special in because can be a register or a konstant. a bitflag is read to determine which
|
||||
def __readRK(self, rk: int) -> str:
|
||||
if (rk & (1 << 8)) > 0:
|
||||
return self.chunk.constants[(rk & ~(1 << 8))].toCode()
|
||||
else:
|
||||
return self.__getReg(rk)
|
||||
|
||||
def parseExpr(self):
|
||||
instr = self.__getCurrInstr()
|
||||
|
||||
# python, add switch statements *please*
|
||||
if instr.opcode == Opcodes.MOVE: # move is a fake ABC instr, C is ignored
|
||||
# move registers
|
||||
self.__setReg(instr.A, self.__getReg(instr.B))
|
||||
elif instr.opcode == Opcodes.LOADK:
|
||||
self.__setReg(instr.A, self.chunk.constants[instr.B].toCode())
|
||||
elif instr.opcode == Opcodes.LOADBOOL:
|
||||
if instr.B == 0:
|
||||
self.__setReg(instr.A, "false")
|
||||
else:
|
||||
self.__setReg(instr.A, "true")
|
||||
elif instr.opcode == Opcodes.GETGLOBAL:
|
||||
self.__setReg(instr.A, self.chunk.constants[instr.B].data)
|
||||
elif instr.opcode == Opcodes.GETTABLE:
|
||||
self.__setReg(instr.A, self.__getReg(instr.B) + "[" + self.__readRK(instr.C) + "]")
|
||||
elif instr.opcode == Opcodes.SETGLOBAL:
|
||||
self.__startStatement()
|
||||
self.__addExpr(self.chunk.constants[instr.B].data + " = " + self.__getReg(instr.A))
|
||||
elif instr.opcode == Opcodes.SETTABLE:
|
||||
self.__startStatement()
|
||||
self.__addExpr(self.__getReg(instr.A) + "[" + self.__readRK(instr.B) + "] = " + self.__readRK(instr.C))
|
||||
elif instr.opcode == Opcodes.ADD:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " + ")
|
||||
elif instr.opcode == Opcodes.SUB:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " - ")
|
||||
elif instr.opcode == Opcodes.MUL:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " * ")
|
||||
elif instr.opcode == Opcodes.DIV:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " / ")
|
||||
elif instr.opcode == Opcodes.MOD:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " % ")
|
||||
elif instr.opcode == Opcodes.POW:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " ^ ")
|
||||
elif instr.opcode == Opcodes.UNM:
|
||||
self.__setReg(instr.A, "-" + self.__getReg(instr.B))
|
||||
elif instr.opcode == Opcodes.NOT:
|
||||
self.__setReg(instr.A, "!" + self.__getReg(instr.B))
|
||||
elif instr.opcode == Opcodes.LEN:
|
||||
self.__setReg(instr.A, "#" + self.__getCurrInstr(instr.B))
|
||||
elif instr.opcode == Opcodes.CONCAT:
|
||||
count = instr.C-instr.B+1
|
||||
concatStr = ""
|
||||
|
||||
# concat all items on stack from RC to RB
|
||||
for i in range(count):
|
||||
concatStr += self.__getReg(instr.B + i) + (" .. " if not i == count - 1 else "")
|
||||
|
||||
self.__setReg(instr.A, concatStr)
|
||||
elif instr.opcode == Opcodes.JMP:
|
||||
pass
|
||||
elif instr.opcode == Opcodes.EQ:
|
||||
self.__startStatement()
|
||||
if instr.A > 0:
|
||||
self.__addExpr("if not ")
|
||||
else:
|
||||
self.__addExpr("if ")
|
||||
self.__addExpr(self.__readRK(instr.B) + " == " + self.__readRK(instr.C) + " ")
|
||||
self.__startScope("then ", self.__getNextInstr().B + 1)
|
||||
|
||||
self.pc += 1 # skip next instr
|
||||
elif instr.opcode == Opcodes.LT:
|
||||
self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " < ")
|
||||
elif instr.opcode == Opcodes.LE:
|
||||
self.__emitOperand(instr.A, instr.B, instr.C, " <= ")
|
||||
elif instr.opcode == Opcodes.CALL:
|
||||
preStr = ""
|
||||
callStr = ""
|
||||
ident = ""
|
||||
|
||||
# parse arguments
|
||||
callStr += self.__getReg(instr.A) + "("
|
||||
for i in range(instr.A + 1, instr.A + instr.B):
|
||||
callStr += self.__getReg(i) + (", " if not i + 1 == instr.A + instr.B else "")
|
||||
callStr += ")"
|
||||
|
||||
# parse return values
|
||||
if instr.C > 1:
|
||||
preStr = "local "
|
||||
for indx in range(instr.A, instr.A + instr.C - 1):
|
||||
if indx in self.locals:
|
||||
ident = self.locals[indx]
|
||||
else:
|
||||
ident = self.__makeLocalIdentifier(indx)
|
||||
preStr += ident
|
||||
|
||||
# normally setReg() does this
|
||||
self.top[indx] = ident
|
||||
|
||||
# just so we don't have a trailing ', '
|
||||
preStr += ", " if not indx == instr.A + instr.C - 2 else ""
|
||||
preStr += " = "
|
||||
|
||||
self.__startStatement()
|
||||
self.__addExpr(preStr + callStr)
|
||||
elif instr.opcode == Opcodes.RETURN:
|
||||
self.__startStatement()
|
||||
pass # no-op for now
|
||||
else:
|
||||
raise Exception("unsupported instruction: %s" % instr.toString())
|
||||
Reference in New Issue
Block a user