Translator: add a bounded cache on `from_expr`

1 files changed, 16 insertions, 1 deletions

diff --git a/miasm2/ir/translators/translator.py b/miasm2/ir/translators/translator.py
index 90e5890c..e3641843 100644
--- a/miasm2/ir/translators/translator.py
+++ b/miasm2/ir/translators/translator.py
@@ -1,4 +1,5 @@
 import miasm2.expression.expression as m2_expr
+from miasm2.core.utils import BoundedDict
 
 
 class Translator(object):
@@ -34,6 +35,12 @@ class Translator(object):
         "Return the list of registered languages"
         return [translator.__LANG__ for translator in cls.available_translators]
 
+    def __init__(self, cache_size=1000):
+        """Instance a translator
+        @cache_size: (optional) Expr cache size
+        """
+        self._cache = BoundedDict(cache_size)
+
     def from_ExprInt(self, expr):
         """Translate an ExprInt
         @expr: ExprInt to translate
@@ -86,6 +93,11 @@ class Translator(object):
         """Translate an expression according to its type
         @expr: expression to translate
         """
+        # Use cache
+        if expr in self._cache:
+            return self._cache[expr]
+
+        # Handle Expr type
         handlers = {m2_expr.ExprInt: self.from_ExprInt,
                     m2_expr.ExprId: self.from_ExprId,
                     m2_expr.ExprCompose: self.from_ExprCompose,
@@ -97,6 +109,9 @@ class Translator(object):
                     }
         for target, handler in handlers.iteritems():
             if isinstance(expr, target):
-                return handler(expr)
+                ## Compute value and update the internal cache
+                ret = handler(expr)
+                self._cache[expr] = ret
+                return ret
         raise ValueError("Unhandled type for %s" % expr)