diff options
| -rw-r--r-- | miasm2/expression/simplifications.py | 6 | ||||
| -rw-r--r-- | miasm2/expression/simplifications_common.py | 53 | ||||
| -rw-r--r-- | miasm2/expression/simplifications_explicit.py | 8 | ||||
| -rw-r--r-- | test/expression/simplifications.py | 31 |
4 files changed, 88 insertions, 10 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..87720e08 100644 --- a/miasm2/expression/simplifications_common.py +++ b/miasm2/expression/simplifications_common.py @@ -1375,6 +1375,59 @@ 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 diff --git a/test/expression/simplifications.py b/test/expression/simplifications.py index 5bca3fa9..263479b7 100644 --- a/test/expression/simplifications.py +++ b/test/expression/simplifications.py @@ -101,6 +101,10 @@ i3 = ExprInt(3, 32) im1 = ExprInt(-1, 32) im2 = ExprInt(-2, 32) +bi0 = ExprInt(0, 1) +bi1 = ExprInt(1, 1) + + icustom = ExprInt(0x12345678, 32) cc = ExprCond(a, b, c) @@ -692,6 +696,33 @@ to_test = [ (a8.zeroExtend(32)[2:5], a8[2:5]), + + ( + ExprCond(a + b, a, b), + ExprCond(ExprOp(TOK_EQUAL, a, -b), b, a) + ), + + ( + ExprCond(a + i1, a, b), + ExprCond(ExprOp(TOK_EQUAL, a, im1), b, a) + ), + + + ( + ExprCond(ExprOp(TOK_EQUAL, a, i1), bi1, bi0), + ExprOp(TOK_EQUAL, a, i1) + ), + + ( + ExprCond(ExprOp(TOK_INF_SIGNED, a, i1), bi1, bi0), + ExprOp(TOK_INF_SIGNED, a, i1) + ), + + ( + ExprOp(TOK_INF_EQUAL_UNSIGNED, a, i0), + ExprOp(TOK_EQUAL, a, i0) + ), + ] for e_input, e_check in to_test: |