mirror of
https://github.com/cea-sec/miasm
synced 2026-06-21 13:48:18 +00:00
Fabrice Desclaux
47 lines
1.5 KiB
Python
47 lines
1.5 KiB
Python
import miasm2.expression.expression as m2_expr
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from miasm2.expression.simplifications import expr_simp
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from pdb import pm
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print """
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Expression simplification demo: Adding a simplification:
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a + a + a == a * 3
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More detailed examples can be found in miasm2/expression/simplification*.
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"""
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# Define the simplification method
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## @expr_simp is the current expression simplifier instance
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## (for recursive simplifications)
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## @expr is the expression to (perhaps) simplify
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def simp_add_mul(expr_simp, expr):
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"Naive Simplification: a + a + a == a * 3"
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# Match the expected form
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## isinstance(expr, m2_expr.ExprOp) is not needed: simplifications are
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## attached to expression types
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if expr.op == "+" and \
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len(expr.args) == 3 and \
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expr.args.count(expr.args[0]) == len(expr.args):
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# Effective simplification
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return m2_expr.ExprOp("*", expr.args[0],
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m2_expr.ExprInt(3, expr.args[0].size))
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else:
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# Do not simplify
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return expr
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a = m2_expr.ExprId('a', 32)
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base_expr = a + a + a
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print "Without adding the simplification:"
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print "\t%s = %s" % (base_expr, expr_simp(base_expr))
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# Enable pass
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expr_simp.enable_passes({m2_expr.ExprOp: [simp_add_mul]})
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print "After adding the simplification:"
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print "\t%s = %s" % (base_expr, expr_simp(base_expr))
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# Automatic fail
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assert(expr_simp(base_expr) == m2_expr.ExprOp("*", a,
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m2_expr.ExprInt(3, a.size)))
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