Example: add constant expression propagation

1 files changed, 54 insertions, 0 deletions

diff --git a/example/expression/constant_propagation.py b/example/expression/constant_propagation.py
new file mode 100644
index 00000000..70394580
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+++ b/example/expression/constant_propagation.py
@@ -0,0 +1,54 @@
+"""
+Example of "constant expression" propagation.
+A "constant expression" is an expression based on constants or init regs.
+
+"""
+
+from argparse import ArgumentParser
+
+from miasm2.arch.x86.disasm import dis_x86_32 as dis_engine
+from miasm2.analysis.machine import Machine
+from miasm2.analysis.binary import Container
+from miasm2.analysis.cst_propag import propagate_cst_expr
+from miasm2.analysis.data_flow import dead_simp
+from miasm2.expression.simplifications import expr_simp
+
+
+parser = ArgumentParser("Constant expression propagation")
+parser.add_argument('filename', help="File to analyze")
+parser.add_argument('address', help="Starting address for disassembly engine")
+parser.add_argument('-s', "--simplify", action="store_true",
+                    help="Apply simplifications rules (liveness, graph simplification, ...)")
+
+args = parser.parse_args()
+
+
+machine = Machine("x86_32")
+
+cont = Container.from_stream(open(args.filename))
+ira, dis_engine = machine.ira, machine.dis_engine
+mdis = dis_engine(cont.bin_stream)
+ir_arch = ira(mdis.symbol_pool)
+addr = int(args.address, 0)
+
+
+blocks = mdis.dis_multiblock(addr)
+for block in blocks:
+    ir_arch.add_block(block)
+
+
+init_infos = ir_arch.arch.regs.regs_init
+cst_propag_link = propagate_cst_expr(ir_arch, addr, init_infos)
+
+if args.simplify:
+    ir_arch.simplify(expr_simp)
+    modified = True
+    while modified:
+        modified = False
+        modified |= dead_simp(ir_arch)
+        modified |= ir_arch.remove_empty_assignblks()
+        modified |= ir_arch.remove_jmp_blocks()
+        modified |= ir_arch.merge_blocks()
+
+
+open("%s.propag.dot" % args.filename, 'w').write(ir_arch.graph.dot())