Пример #1
0
    def test_pysmt_operations(self, width, x, y):
        try:
            from pysmt import shortcuts as sc
        except ImportError:
            return

        modulus = 2 ** width
        x = x % modulus
        y = y % modulus
        bvx = Constant(x, width)
        bvy = Constant(y, width)
        psx = sc.BV(x, width)
        psy = sc.BV(y, width)

        def eval_pysmt(pysmt_var):
            return pysmt_var.simplify().constant_value()

        self.assertEqual(~bvx, eval_pysmt(sc.BVNot(psx)))
        self.assertEqual(bvx & bvy, eval_pysmt(sc.BVAnd(psx, psy)))
        self.assertEqual(bvx | bvy, eval_pysmt(sc.BVOr(psx, psy)))
        self.assertEqual(bvx ^ bvy, eval_pysmt(sc.BVXor(psx, psy)))

        self.assertEqual(BvComp(bvx, bvy), eval_pysmt(sc.BVComp(psx, psy)))
        self.assertEqual((bvx < bvy), eval_pysmt(sc.BVULT(psx, psy)))
        self.assertEqual((bvx <= bvy), eval_pysmt(sc.BVULE(psx, psy)))
        self.assertEqual((bvx > bvy), eval_pysmt(sc.BVUGT(psx, psy)))
        self.assertEqual((bvx >= bvy), eval_pysmt(sc.BVUGE(psx, psy)))

        r = y % bvx.width
        self.assertEqual(bvx << bvy, eval_pysmt(sc.BVLShl(psx, psy)))
        self.assertEqual(bvx >> bvy, eval_pysmt(sc.BVLShr(psx, psy)))
        self.assertEqual(RotateLeft(bvx, r), eval_pysmt(sc.BVRol(psx, r)))
        self.assertEqual(RotateRight(bvx, r), eval_pysmt(sc.BVRor(psx, r)))

        bvb = Constant(y % 2, 1)
        psb = sc.Bool(bool(bvb))
        self.assertEqual(Ite(bvb, bvx, bvy), eval_pysmt(sc.Ite(psb, psx, psy)))
        j = y % bvx.width
        self.assertEqual(bvx[:j], eval_pysmt(sc.BVExtract(psx, start=j)))
        self.assertEqual(bvx[j:], eval_pysmt(sc.BVExtract(psx, end=j)))
        self.assertEqual(Concat(bvx, bvy), eval_pysmt(sc.BVConcat(psx, psy)))
        self.assertEqual(ZeroExtend(bvx, j), eval_pysmt(sc.BVZExt(psx, j)))
        self.assertEqual(Repeat(bvx, 1 + j), eval_pysmt(psx.BVRepeat(1 + j)))

        self.assertEqual(-bvx, eval_pysmt(sc.BVNeg(psx)))
        self.assertEqual(bvx + bvy, eval_pysmt(sc.BVAdd(psx, psy)))
        self.assertEqual(bvx - bvy, eval_pysmt(sc.BVSub(psx, psy)))
        self.assertEqual(bvx * bvy, eval_pysmt(sc.BVMul(psx, psy)))
        if bvy > 0:
            self.assertEqual(bvx / bvy, eval_pysmt(sc.BVUDiv(psx, psy)))
            self.assertEqual(bvx % bvy, eval_pysmt(sc.BVURem(psx, psy)))
Пример #2
0
 def bvsub(self, other):
     return type(self)(smt.BVSub(self.value, other.value))
Пример #3
0
def bv2pysmt(bv):
    """Convert a bit-vector type to a pySMT type.

        >>> from arxpy.bitvector.core import Constant, Variable
        >>> from arxpy.diffcrypt.smt import bv2pysmt
        >>> bv2pysmt(Constant(0b00000001, 8))
        1_8
        >>> x, y = Variable("x", 8), Variable("y", 8)
        >>> bv2pysmt(x)
        x
        >>> bv2pysmt(x +  y)
        (x + y)
        >>> bv2pysmt(x <=  y)
        (x u<= y)
        >>> bv2pysmt(x[4: 2])
        x[2:4]

    """
    msg = "unknown conversion of {} to a pySMT type".format(type(bv).__name__)

    if isinstance(bv, int):
        return bv

    if isinstance(bv, core.Variable):
        return sc.Symbol(bv.name, typing.BVType(bv.width))

    if isinstance(bv, core.Constant):
        return sc.BV(bv.val, bv.width)

    if isinstance(bv, operation.Operation):
        args = [bv2pysmt(a) for a in bv.args]

        if type(bv) == operation.BvNot:
            if args[0].is_equals():
                return sc.Not(*args)
            else:
                return sc.BVNot(*args)

        if type(bv) == operation.BvAnd:
            return sc.BVAnd(*args)

        if type(bv) == operation.BvOr:
            return sc.BVOr(*args)

        if type(bv) == operation.BvXor:
            return sc.BVXor(*args)

        if type(bv) == operation.BvComp:
            # return sc.BVComp(*args)
            return sc.Equals(*args)

        if type(bv) == operation.BvUlt:
            return sc.BVULT(*args)

        if type(bv) == operation.BvUle:
            return sc.BVULE(*args)

        if type(bv) == operation.BvUgt:
            return sc.BVUGT(*args)

        if type(bv) == operation.BvUge:
            return sc.BVUGE(*args)

        if type(bv) == operation.BvShl:
            # Left hand side width must be a power of 2
            if (args[0].bv_width() & (args[0].bv_width() - 1)) == 0:
                return sc.BVLShl(*args)
            else:
                x, r = bv.args
                offset = 0
                while (x.width & (x.width - 1)) != 0:
                    x = operation.ZeroExtend(x, 1)
                    r = operation.ZeroExtend(r, 1)
                    offset += 1

                shift = bv2pysmt(x << r)
                return sc.BVExtract(shift, end=shift.bv_width() - offset - 1)
            # width = args[0].bv_width()
            # assert (width & (width - 1)) == 0  # power of 2
            # return sc.BVLShl(*args)

        if type(bv) == operation.BvLshr:
            # Left hand side width must be a power of 2
            if (args[0].bv_width() & (args[0].bv_width() - 1)) == 0:
                return sc.BVLShr(*args)
            else:
                x, r = bv.args
                offset = 0
                while (x.width & (x.width - 1)) != 0:
                    x = operation.ZeroExtend(x, 1)
                    r = operation.ZeroExtend(r, 1)
                    offset += 1

                shift = bv2pysmt(x >> r)
                return sc.BVExtract(shift, end=shift.bv_width() - offset - 1)
            # width = args[1].bv_width()
            # assert (width & (width - 1)) == 0  # power of 2
            # return sc.BVLShr(*args)

        if type(bv) == operation.RotateLeft:
            # Left hand side width must be a power of 2
            if (args[0].bv_width() & (args[0].bv_width() - 1)) == 0:
                return sc.BVRol(*args)
            else:
                x, r = bv.args
                n = x.width
                return bv2pysmt(operation.Concat(x[n - r - 1:],
                                                 x[n - 1:n - r]))

        if type(bv) == operation.RotateRight:
            # Left hand side width must be a power of 2
            if (args[0].bv_width() & (args[0].bv_width() - 1)) == 0:
                return sc.BVRor(*args)
            else:
                x, r = bv.args
                n = x.width
                return bv2pysmt(operation.Concat(x[r - 1:], x[n - 1:r]))

        if type(bv) == operation.Ite:
            if args[0].is_equals():
                a0 = args[0]
            else:
                a0 = sc.Equals(args[0], bv2pysmt(core.Constant(1, 1)))

            return sc.Ite(a0, *args[1:])

        if type(bv) == operation.Extract:
            return sc.BVExtract(args[0], args[2], args[1])

        if type(bv) == operation.Concat:
            return sc.BVConcat(*args)

        if type(bv) == operation.ZeroExtend:
            return sc.BVZExt(*args)

        if type(bv) == operation.Repeat:
            return args[0].BVRepeat(args[1])

        if type(bv) == operation.BvNeg:
            return sc.BVNeg(*args)

        if type(bv) == operation.BvAdd:
            return sc.BVAdd(*args)

        if type(bv) == operation.BvSub:
            return sc.BVSub(*args)

        if type(bv) == operation.BvMul:
            return sc.BVMul(*args)

        if type(bv) == operation.BvMul:
            return sc.BVMul(*args)

        if type(bv) == operation.BvUdiv:
            return sc.BVUDiv(*args)

        if type(bv) == operation.BvUrem:
            return sc.BVURem(*args)

        raise NotImplementedError(msg)