java_class_typet: record method descriptor

Along with the basename already stored on class_typet::methodt, this means we can compare
two Java methods for name and descriptor compatibility without having to parse the composite
method identifier.

Author: smowton

jbmc/src/java_bytecode/java_bytecode_convert_method.cpp

@@ -410,14 +410,13 @@ void java_bytecode_convert_method_lazy(
 
   if(!m.is_static)
   {
-    class_typet::methodt new_method;
-    new_method.set_name(method_symbol.name);
+    java_class_typet::methodt new_method{method_symbol.name, method_type};
     new_method.set_base_name(method_symbol.base_name);
     new_method.set_pretty_name(method_symbol.pretty_name);
     new_method.set_access(member_type.get_access());
-    new_method.type() = method_symbol.type;
+    new_method.set_descriptor(m.descriptor);
 
-    to_class_type(class_symbol.type)
+    to_java_class_type(class_symbol.type)
       .methods()
       .emplace_back(std::move(new_method));
   }

jbmc/src/java_bytecode/java_types.h

@@ -283,6 +283,18 @@ class java_class_typet:public class_typet
     {
       set(ID_is_native_method, is_native);
     }
+
+    /// Gets the method's descriptor -- the mangled form of its type
+    const irep_idt &get_descriptor() const
+    {
+      return get(ID_object_descriptor);
+    }
+
+    /// Sets the method's descriptor -- the mangled form of its type
+    void set_descriptor(const irep_idt &id)
+    {
+      set(ID_object_descriptor, id);
+    }
   };
 
   using methodst = std::vector<methodt>;