robustly handle 'missing' enum values

decompiler/structures/pseudo/complextypes.py

@@ -108,8 +108,9 @@ class Enum(ComplexType):
     def add_member(self, member: ComplexTypeMember):
         self.members[member.value] = member
 
-    def get_name_by_value(self, value: int) -> str:
-        return self.members.get(value).name
+    def get_name_by_value(self, value: int) -> Optional[str]:
+        member = self.members.get(value)
+        return member.name if member is not None else None
 
     def declaration(self) -> str:
         members = ",\n\t".join(f"{x.name} = {x.value}" for x in self.members.values())

decompiler/structures/pseudo/expressions.py

@@ -191,7 +191,10 @@ def __str__(self) -> str:
         Constants of type Enum are represented as strings (corresponding enumerator identifiers).
         """
         if isinstance(self._type, Enum):
-            return self._type.get_name_by_value(self.value)
+            name = self._type.get_name_by_value(self.value)
+            if name is not None:
+                return name
+            # otherwise, i.e. if value is not found in Enum class, fall through
         if self._type.is_boolean:
             return "true" if self.value else "false"
         if isinstance(self.value, str):