ethcore: add missing builtins benchmarks (#9170)

* ethcore: add modexp benchmarks

* ethcore: add_bn_128_add benchmark

ethcore/src/builtin.rs

@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
+//! Standard built-in contracts.
+
 use std::cmp::{max, min};
 use std::io::{self, Read};
 
@@ -27,6 +29,7 @@ use bytes::BytesRef;
 use ethkey::{Signature, recover as ec_recover};
 use ethjson;
 
+/// Execution error.
 #[derive(Debug)]
 pub struct Error(pub &'static str);
 
@@ -207,8 +210,8 @@ impl From<ethjson::spec::Builtin> for Builtin {
 	}
 }
 
-// Ethereum builtin creator.
-fn ethereum_builtin(name: &str) -> Box<Impl> {
+/// Ethereum built-in factory.
+pub fn ethereum_builtin(name: &str) -> Box<Impl> {
 	match name {
 		"identity" => Box::new(Identity) as Box<Impl>,
 		"ecrecover" => Box::new(EcRecover) as Box<Impl>,

ethcore/src/lib.rs

@@ -146,6 +146,7 @@ pub mod views;
 
 pub mod account_provider;
 pub mod block;
+pub mod builtin;
 pub mod client;
 pub mod db;
 pub mod encoded;
@@ -168,7 +169,6 @@ pub mod verification;
 mod cache_manager;
 mod pod_account;
 mod account_db;
-mod builtin;
 mod externalities;
 mod blockchain;
 mod factory;