Merge pull request #564 from commial/feature/compose-mem-simpl

Add a new simplification merging ExprMem sharing the same base in ExprCompose

2 files changed, 16 insertions, 0 deletions

diff --git a/miasm2/expression/simplifications_common.py b/miasm2/expression/simplifications_common.py
index 01db7597..eb9d0958 100644
--- a/miasm2/expression/simplifications_common.py
+++ b/miasm2/expression/simplifications_common.py
@@ -542,6 +542,17 @@ def simp_compose(e_s, e):
             new_e = args[0].arg >> ExprInt(args[0].start, args[0].arg.size)
             return new_e
 
+    # {@X[base + i] 0 X, @Y[base + i + X] X (X + Y)} => @(X+Y)[base + i]
+    for i, arg in enumerate(args[:-1]):
+        nxt = args[i + 1]
+        if arg.is_mem() and nxt.is_mem():
+            gap = e_s(nxt.arg - arg.arg)
+            if gap.is_int() and int(gap) == arg.size / 8:
+                args = args[:i] + [ExprMem(arg.arg,
+                                          arg.size + nxt.size)] + args[i + 2:]
+                return ExprCompose(*args)
+
+
     # Compose with ExprCond with integers for src1/src2 and intergers =>
     # propagage integers
     # {XXX?(0x0,0x1)?(0x0,0x1),0,8, 0x0,8,32} => XXX?(int1, int2)
diff --git a/test/expression/simplifications.py b/test/expression/simplifications.py
index 60c328dc..efabddb5 100644
--- a/test/expression/simplifications.py
+++ b/test/expression/simplifications.py
@@ -314,6 +314,11 @@ to_test = [(ExprInt(1, 32) - ExprInt(1, 32), ExprInt(0, 32)),
     (ExprOp("imod", ExprInt(0x0123, 16), ExprInt(0xfffb, 16))[:8],
      ExprInt(0x01, 8)),
 
+    (ExprCompose(ExprInt(0x0123, 16), ExprMem(a + ExprInt(0x40, a.size), 16),
+                 ExprMem(a + ExprInt(0x42, a.size), 16), ExprInt(0x0321, 16)),
+     ExprCompose(ExprInt(0x0123, 16), ExprMem(a + ExprInt(0x40, a.size), 32),
+                 ExprInt(0x0321, 16))),
+
 ]
 
 for e, e_check in to_test[:]: