diff options
| -rw-r--r-- | miasm2/expression/simplifications_common.py | 35 | ||||
| -rw-r--r-- | test/expression/simplifications.py | 45 |
2 files changed, 59 insertions, 21 deletions
diff --git a/miasm2/expression/simplifications_common.py b/miasm2/expression/simplifications_common.py index 22e328e1..ccb97cb3 100644 --- a/miasm2/expression/simplifications_common.py +++ b/miasm2/expression/simplifications_common.py @@ -196,21 +196,34 @@ def simp_cst_propagation(e_s, expr): args[1].arg == args[0].size): return args[0] - # A <<< X <<< Y => A <<< (X+Y) (ou <<< >>>) + # (A <<< X) <<< Y => A <<< (X+Y) (or <<< >>>) if X + Y does not overflow if (op_name in ['<<<', '>>>'] and args[0].is_op() and args[0].op in ['<<<', '>>>']): - op1 = op_name - op2 = args[0].op - if op1 == op2: - op_name = op1 - args1 = args[0].args[1] + args[1] - else: - op_name = op2 - args1 = args[0].args[1] - args[1] + A = args[0].args[0] + X = args[0].args[1] + Y = args[1] + if op_name != args[0].op and e_s(X - Y) == ExprInt(0, X.size): + return args[0].args[0] + elif X.is_int() and Y.is_int(): + new_X = int(X) % expr.size + new_Y = int(Y) % expr.size + if op_name == args[0].op: + rot = (new_X + new_Y) % expr.size + op = op_name + else: + rot = new_Y - new_X + op = op_name + if rot < 0: + rot = - rot + op = {">>>": "<<<", "<<<": ">>>"}[op_name] + args = [A, ExprInt(rot, expr.size)] + op_name = op - args0 = args[0].args[0] - args = [args0, args1] + else: + # Do not consider this case, too tricky (overflow on addition / + # substraction) + pass # A >> X >> Y => A >> (X+Y) if X + Y does not overflow # To be sure, only consider the simplification when X.msb and Y.msb are 0 diff --git a/test/expression/simplifications.py b/test/expression/simplifications.py index cb8dc4f8..2650d4d1 100644 --- a/test/expression/simplifications.py +++ b/test/expression/simplifications.py @@ -86,6 +86,13 @@ f = ExprId('f', size=64) b_msb_null = b[:31].zeroExtend(32) c_msb_null = c[:31].zeroExtend(32) +a31 = ExprId('a31', 31) +b31 = ExprId('b31', 31) +c31 = ExprId('c31', 31) +b31_msb_null = ExprId('b31', 31)[:30].zeroExtend(31) +c31_msb_null = ExprId('c31', 31)[:30].zeroExtend(31) + + m = ExprMem(a) s = a[:8] @@ -120,17 +127,35 @@ to_test = [(ExprInt(1, 32) - ExprInt(1, 32), ExprInt(0, 32)), (ExprOp('>>>', a, ExprInt(32, 32)), a), (ExprOp('>>>', a, ExprInt(0, 32)), a), (ExprOp('<<', a, ExprInt(0, 32)), a), + (ExprOp('<<<', a31, ExprInt(31, 31)), a31), + (ExprOp('>>>', a31, ExprInt(31, 31)), a31), + (ExprOp('>>>', a31, ExprInt(0, 31)), a31), + (ExprOp('<<', a31, ExprInt(0, 31)), a31), + + (ExprOp('<<<', a31, ExprOp('<<<', b31, c31)), + ExprOp('<<<', a31, ExprOp('<<<', b31, c31))), + (ExprOp('<<<', ExprOp('>>>', a31, b31), c31), + ExprOp('<<<', ExprOp('>>>', a31, b31), c31)), + (ExprOp('>>>', ExprOp('<<<', a31, b31), c31), + ExprOp('>>>', ExprOp('<<<', a31, b31), c31)), + (ExprOp('>>>', ExprOp('<<<', a31, b31), b31), + a31), + (ExprOp('<<<', ExprOp('>>>', a31, b31), b31), + a31), + (ExprOp('>>>', ExprOp('>>>', a31, b31), b31), + ExprOp('>>>', ExprOp('>>>', a31, b31), b31)), + (ExprOp('<<<', ExprOp('<<<', a31, b31), b31), + ExprOp('<<<', ExprOp('<<<', a31, b31), b31)), + + (ExprOp('>>>', ExprOp('<<<', a31, ExprInt(0x1234, 31)), ExprInt(0x1111, 31)), + ExprOp('>>>', a31, ExprInt(0x13, 31))), + (ExprOp('<<<', ExprOp('>>>', a31, ExprInt(0x1234, 31)), ExprInt(0x1111, 31)), + ExprOp('<<<', a31, ExprInt(0x13, 31))), + (ExprOp('>>>', ExprOp('<<<', a31, ExprInt(-1, 31)), ExprInt(0x1111, 31)), + ExprOp('>>>', a31, ExprInt(0x1c, 31))), + (ExprOp('<<<', ExprOp('>>>', a31, ExprInt(-1, 31)), ExprInt(0x1111, 31)), + ExprOp('<<<', a31, ExprInt(0x1c, 31))), - (ExprOp('<<<', a, ExprOp('<<<', b, c)), - ExprOp('<<<', a, ExprOp('<<<', b, c))), - (ExprOp('<<<', ExprOp('<<<', a, b), c), - ExprOp('<<<', a, (b+c))), - (ExprOp('<<<', ExprOp('>>>', a, b), c), - ExprOp('>>>', a, (b-c))), - (ExprOp('>>>', ExprOp('<<<', a, b), c), - ExprOp('<<<', a, (b-c))), - (ExprOp('>>>', ExprOp('<<<', a, b), b), - a), (ExprOp(">>>", ExprInt(0x1000, 16), ExprInt(0x11, 16)), ExprInt(0x800, 16)), (ExprOp("<<<", ExprInt(0x1000, 16), ExprInt(0x11, 16)), |