diff options
| -rw-r--r-- | miasm2/expression/simplifications.py | 20 | ||||
| -rw-r--r-- | miasm2/expression/simplifications_explicit.py | 155 |
2 files changed, 175 insertions, 0 deletions
diff --git a/miasm2/expression/simplifications.py b/miasm2/expression/simplifications.py index e6c5dc54..3f7b9db9 100644 --- a/miasm2/expression/simplifications.py +++ b/miasm2/expression/simplifications.py @@ -6,6 +6,7 @@ import logging from miasm2.expression import simplifications_common from miasm2.expression import simplifications_cond +from miasm2.expression import simplifications_explicit from miasm2.expression.expression_helper import fast_unify import miasm2.expression.expression as m2_expr @@ -55,6 +56,16 @@ class ExpressionSimplifier(object): } + # Available passes lists are: + # - highlevel: transform high level operators to explicit computations + PASS_HIGH_TO_EXPLICIT = { + m2_expr.ExprOp: [ + simplifications_explicit.simp_flags, + simplifications_explicit.simp_ext, + ], + } + + def __init__(self): self.expr_simp_cb = {} self.simplified_exprs = set() @@ -136,3 +147,12 @@ class ExpressionSimplifier(object): # Public ExprSimplificationPass instance with commons passes 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) + +expr_simp_explicit = ExpressionSimplifier() +expr_simp_explicit.enable_passes(ExpressionSimplifier.PASS_COMMONS) +expr_simp_explicit.enable_passes(ExpressionSimplifier.PASS_HIGH_TO_EXPLICIT) diff --git a/miasm2/expression/simplifications_explicit.py b/miasm2/expression/simplifications_explicit.py new file mode 100644 index 00000000..78e056ec --- /dev/null +++ b/miasm2/expression/simplifications_explicit.py @@ -0,0 +1,155 @@ +from miasm2.expression.modint import size2mask +from miasm2.expression.expression import ExprInt, ExprCond, ExprOp, \ + ExprCompose + + +def simp_ext(_, expr): + if expr.op.startswith('zeroExt_'): + arg = expr.args[0] + if expr.size == arg.size: + return arg + return ExprCompose(arg, ExprInt(0, expr.size - arg.size)) + + if expr.op.startswith("signExt_"): + arg = expr.args[0] + add_size = expr.size - arg.size + new_expr = ExprCompose( + arg, + ExprCond( + arg.msb(), + ExprInt(size2mask(add_size), add_size), + ExprInt(0, add_size) + ) + ) + return new_expr + return expr + + +def simp_flags(_, expr): + args = expr.args + + if expr.is_op("FLAG_EQ"): + return ExprCond(args[0], ExprInt(0, 1), ExprInt(1, 1)) + + elif expr.is_op("FLAG_EQ_AND"): + op1, op2 = args + return ExprCond(op1 & op2, ExprInt(0, 1), ExprInt(1, 1)) + + elif expr.is_op("FLAG_SIGN_SUB"): + return (args[0] - args[1]).msb() + + elif expr.is_op("FLAG_EQ_CMP"): + return ExprCond( + args[0] - args[1], + ExprInt(0, 1), + ExprInt(1, 1), + ) + + elif expr.is_op("FLAG_ADD_CF"): + op1, op2 = args + res = op1 + op2 + return (((op1 ^ op2) ^ res) ^ ((op1 ^ res) & (~(op1 ^ op2)))).msb() + + elif expr.is_op("FLAG_SUB_CF"): + op1, op2 = args + res = op1 - op2 + return (((op1 ^ op2) ^ res) ^ ((op1 ^ res) & (op1 ^ op2))).msb() + + elif expr.is_op("FLAG_ADD_OF"): + op1, op2 = args + res = op1 + op2 + return (((op1 ^ res) & (~(op1 ^ op2)))).msb() + + elif expr.is_op("FLAG_SUB_OF"): + op1, op2 = args + res = op1 - op2 + return (((op1 ^ res) & (op1 ^ op2))).msb() + + elif expr.is_op("FLAG_EQ_ADDWC"): + op1, op2, op3 = args + return ExprCond( + op1 + op2 + op3.zeroExtend(op1.size), + ExprInt(0, 1), + ExprInt(1, 1), + ) + + elif expr.is_op("FLAG_ADDWC_OF"): + op1, op2, op3 = args + res = op1 + op2 + op3.zeroExtend(op1.size) + return (((op1 ^ res) & (~(op1 ^ op2)))).msb() + + elif expr.is_op("FLAG_SUBWC_OF"): + op1, op2, op3 = args + res = op1 - (op2 + op3.zeroExtend(op1.size)) + return (((op1 ^ res) & (op1 ^ op2))).msb() + + elif expr.is_op("FLAG_ADDWC_CF"): + op1, op2, op3 = args + res = op1 + op2 + op3.zeroExtend(op1.size) + return (((op1 ^ op2) ^ res) ^ ((op1 ^ res) & (~(op1 ^ op2)))).msb() + + elif expr.is_op("FLAG_SUBWC_CF"): + op1, op2, op3 = args + res = op1 - (op2 + op3.zeroExtend(op1.size)) + return (((op1 ^ op2) ^ res) ^ ((op1 ^ res) & (op1 ^ op2))).msb() + + elif expr.is_op("FLAG_SIGN_ADDWC"): + op1, op2, op3 = args + return (op1 + op2 + op3.zeroExtend(op1.size)).msb() + + elif expr.is_op("FLAG_SIGN_SUBWC"): + op1, op2, op3 = args + return (op1 - (op2 + op3.zeroExtend(op1.size))).msb() + + + elif expr.is_op("FLAG_EQ_SUBWC"): + op1, op2, op3 = args + res = op1 - (op2 + op3.zeroExtend(op1.size)) + return ExprCond(res, ExprInt(0, 1), ExprInt(1, 1)) + + elif expr.is_op("CC_U<="): + op_cf, op_zf = args + return op_cf | op_zf + + elif expr.is_op("CC_U>="): + op_cf, = args + return ~op_cf + + elif expr.is_op("CC_S<"): + op_nf, op_of = args + return op_nf ^ op_of + + elif expr.is_op("CC_S>"): + op_nf, op_of, op_zf = args + return ~(op_zf | (op_nf ^ op_of)) + + elif expr.is_op("CC_S<="): + op_nf, op_of, op_zf = args + return op_zf | (op_nf ^ op_of) + + elif expr.is_op("CC_S>="): + op_nf, op_of = args + return ~(op_nf ^ op_of) + + elif expr.is_op("CC_U>"): + op_cf, op_zf = args + return ~(op_cf | op_zf) + + elif expr.is_op("CC_U<"): + op_cf, = args + return op_cf + + elif expr.is_op("CC_NEG"): + op_nf, = args + return op_nf + + elif expr.is_op("CC_EQ"): + op_zf, = args + return op_zf + + elif expr.is_op("CC_NE"): + op_zf, = args + return ~op_zf + + return expr + |