diff options
Diffstat (limited to 'miasm2/expression')
| -rw-r--r-- | miasm2/expression/simplifications.py | 6 | ||||
| -rw-r--r-- | miasm2/expression/simplifications_common.py | 112 | ||||
| -rw-r--r-- | miasm2/expression/simplifications_explicit.py | 8 |
3 files changed, 94 insertions, 32 deletions
diff --git a/miasm2/expression/simplifications.py b/miasm2/expression/simplifications.py index 8ea9c41f..483331a6 100644 --- a/miasm2/expression/simplifications.py +++ b/miasm2/expression/simplifications.py @@ -55,6 +55,7 @@ class ExpressionSimplifier(object): simplifications_common.simp_zeroext_and_cst_eq_cst, simplifications_common.simp_test_signext_inf, simplifications_common.simp_test_zeroext_inf, + simplifications_common.simp_cond_inf_eq_unsigned_zero, ], @@ -67,6 +68,7 @@ class ExpressionSimplifier(object): m2_expr.ExprCond: [ simplifications_common.simp_cond, simplifications_common.simp_cond_zeroext, + simplifications_common.simp_cond_add, # CC op simplifications_common.simp_cond_flag, simplifications_common.simp_cmp_int_arg, @@ -75,11 +77,13 @@ class ExpressionSimplifier(object): simplifications_common.simp_x_and_cst_eq_cst, simplifications_common.simp_cond_logic_ext, simplifications_common.simp_cond_sign_bit, + simplifications_common.simp_cond_eq_1_0, ], m2_expr.ExprMem: [simplifications_common.simp_mem], } + # Heavy passes PASS_HEAVY = {} @@ -193,8 +197,6 @@ class ExpressionSimplifier(object): expr_simp = ExpressionSimplifier() expr_simp.enable_passes(ExpressionSimplifier.PASS_COMMONS) - - expr_simp_high_to_explicit = ExpressionSimplifier() expr_simp_high_to_explicit.enable_passes(ExpressionSimplifier.PASS_HIGH_TO_EXPLICIT) diff --git a/miasm2/expression/simplifications_common.py b/miasm2/expression/simplifications_common.py index 00b14554..a4b7c61e 100644 --- a/miasm2/expression/simplifications_common.py +++ b/miasm2/expression/simplifications_common.py @@ -909,6 +909,7 @@ def simp_cmp_int(expr_simp, expr): """ ({X, 0} == int) => X == int[:] X + int1 == int2 => X == int2-int1 + X ^ int1 == int2 => X == int1^int2 """ if (expr.is_op(TOK_EQUAL) and expr.args[1].is_int() and @@ -922,28 +923,42 @@ def simp_cmp_int(expr_simp, expr): expr = expr_simp( ExprOp(TOK_EQUAL, src, new_int) ) - elif (expr.is_op() and - expr.op in [ - TOK_EQUAL, - ] and - expr.args[1].is_int() and - expr.args[0].is_op("+") and - expr.args[0].args[-1].is_int()): - # X + int1 == int2 => X == int2-int1 - # WARNING: - # X - 0x10 <=u 0x20 gives X in [0x10 0x30] - # which is not equivalet to A <=u 0x10 - - left, right = expr.args - left, int_diff = left.args[:-1], left.args[-1] - if len(left) == 1: - left = left[0] - else: - left = ExprOp('+', *left) - new_int = expr_simp(right - int_diff) - expr = expr_simp( - ExprOp(expr.op, left, new_int), - ) + elif not expr.is_op(TOK_EQUAL): + return expr + assert len(expr.args) == 2 + + left, right = expr.args + if left.is_int() and not right.is_int(): + left, right = right, left + if not right.is_int(): + return expr + if not (left.is_op() and left.op in ['+', '^']): + return expr + if not left.args[-1].is_int(): + return expr + # X + int1 == int2 => X == int2-int1 + # WARNING: + # X - 0x10 <=u 0x20 gives X in [0x10 0x30] + # which is not equivalet to A <=u 0x10 + + left_orig = left + left, last_int = left.args[:-1], left.args[-1] + + if len(left) == 1: + left = left[0] + else: + left = ExprOp(left.op, *left) + + if left_orig.op == "+": + new_int = expr_simp(right - last_int) + elif left_orig.op == '^': + new_int = expr_simp(right ^ last_int) + else: + raise RuntimeError("Unsupported operator") + + expr = expr_simp( + ExprOp(TOK_EQUAL, left, new_int), + ) return expr @@ -1375,6 +1390,59 @@ def simp_cond_sign_bit(_, expr): return ExprCond(cond, expr.src1, expr.src2) +def simp_cond_add(expr_s, expr): + """ + (a+b)?X:Y => (a == b)?Y:X + (a^b)?X:Y => (a == b)?Y:X + """ + cond = expr.cond + if not cond.is_op(): + return expr + if cond.op not in ['+', '^']: + return expr + if len(cond.args) != 2: + return expr + arg1, arg2 = cond.args + if cond.is_op('+'): + new_cond = ExprOp('==', arg1, expr_s(-arg2)) + elif cond.is_op('^'): + new_cond = ExprOp('==', arg1, arg2) + else: + raise ValueError('Bad case') + return ExprCond(new_cond, expr.src2, expr.src1) + + +def simp_cond_eq_1_0(expr_s, expr): + """ + (a == b)?ExprInt(1, 1):ExprInt(0, 1) => a == b + (a <s b)?ExprInt(1, 1):ExprInt(0, 1) => a == b + ... + """ + cond = expr.cond + if not cond.is_op(): + return expr + if cond.op not in [ + TOK_EQUAL, + TOK_INF_SIGNED, TOK_INF_EQUAL_SIGNED, + TOK_INF_UNSIGNED, TOK_INF_EQUAL_UNSIGNED + ]: + return expr + if expr.src1 != ExprInt(1, 1) or expr.src2 != ExprInt(0, 1): + return expr + return cond + + +def simp_cond_inf_eq_unsigned_zero(expr_s, expr): + """ + (a <=u 0) => a == 0 + """ + if not expr.is_op(TOK_INF_EQUAL_UNSIGNED): + return expr + if not expr.args[1].is_int(0): + return expr + return ExprOp(TOK_EQUAL, expr.args[0], expr.args[1]) + + def simp_test_signext_inf(expr_s, expr): """A.signExt() <s int => A <s int[:]""" if not (expr.is_op(TOK_INF_SIGNED) or expr.is_op(TOK_INF_EQUAL_SIGNED)): diff --git a/miasm2/expression/simplifications_explicit.py b/miasm2/expression/simplifications_explicit.py index 4c5dde3e..00892201 100644 --- a/miasm2/expression/simplifications_explicit.py +++ b/miasm2/expression/simplifications_explicit.py @@ -155,13 +155,5 @@ def simp_flags(_, expr): op_nf, = args return ~op_nf - elif expr.is_op(TOK_EQUAL): - arg1, arg2 = args - return ExprCond( - arg1 - arg2, - ExprInt(0, expr.size), - ExprInt(1, expr.size), - ) - return expr |