Reduce asm in Proxy.sol

Author: k06a

packages/lib/contracts/upgradeability/Proxy.sol

@@ -28,23 +28,10 @@ contract Proxy {
    * @param implementation Address to delegate.
    */
   function _delegate(address implementation) internal {
+    (bool success, bytes memory data) = implementation.delegatecall(msg.data);
+    require(success, string(data));
     assembly {
-      // Copy msg.data. We take full control of memory in this inline assembly
-      // block because it will not return to Solidity code. We overwrite the
-      // Solidity scratch pad at memory position 0.
-      calldatacopy(0, 0, calldatasize)
-
-      // Call the implementation.
-      // out and outsize are 0 because we don't know the size yet.
-      let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
-
-      // Copy the returned data.
-      returndatacopy(0, 0, returndatasize)
-
-      switch result
-      // delegatecall returns 0 on error.
-      case 0 { revert(0, returndatasize) }
-      default { return(0, returndatasize) }
+      return(add(data, 32), sload(data))
     }
   }