Merge branch 'fix/64' into 'master'

Resolve "Optimize the proxies to remove state loads from the admin"

Closes #64

See merge request aave-tech/protocol-v2!71

contracts/configuration/LendingPoolAddressesProvider.sol

@@ -3,8 +3,8 @@ pragma solidity ^0.6.8;
 
 import {Ownable} from '@openzeppelin/contracts/access/Ownable.sol';
 import {
-  InitializableAdminUpgradeabilityProxy
+  InitializableImmutableAdminUpgradeabilityProxy
-} from '../libraries/openzeppelin-upgradeability/InitializableAdminUpgradeabilityProxy.sol';
+} from '../libraries/aave-upgradeability/InitializableImmutableAdminUpgradeabilityProxy.sol';
 
 import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddressesProvider.sol';
 
@@ -153,14 +153,14 @@ contract LendingPoolAddressesProvider is Ownable, ILendingPoolAddressesProvider
   function _updateImpl(bytes32 id, address newAddress) internal {
     address payable proxyAddress = payable(_addresses[id]);
 
-    InitializableAdminUpgradeabilityProxy proxy = InitializableAdminUpgradeabilityProxy(
+    InitializableImmutableAdminUpgradeabilityProxy proxy = InitializableImmutableAdminUpgradeabilityProxy(
       proxyAddress
     );
     bytes memory params = abi.encodeWithSignature('initialize(address)', address(this));
 
     if (proxyAddress == address(0)) {
-      proxy = new InitializableAdminUpgradeabilityProxy();
+      proxy = new InitializableImmutableAdminUpgradeabilityProxy(address(this));
-      proxy.initialize(newAddress, address(this), params);
+      proxy.initialize(newAddress, params);
       _addresses[id] = address(proxy);
       emit ProxyCreated(id, address(proxy));
     } else {

contracts/lendingpool/LendingPoolConfigurator.sol

@@ -7,8 +7,8 @@ import {
   VersionedInitializable
 } from '../libraries/openzeppelin-upgradeability/VersionedInitializable.sol';
 import {
-  InitializableAdminUpgradeabilityProxy
+  InitializableImmutableAdminUpgradeabilityProxy
-} from '../libraries/openzeppelin-upgradeability/InitializableAdminUpgradeabilityProxy.sol';
+} from '../libraries/aave-upgradeability/InitializableImmutableAdminUpgradeabilityProxy.sol';
 import {ReserveConfiguration} from '../libraries/configuration/ReserveConfiguration.sol';
 import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddressesProvider.sol';
 import {ILendingPool} from '../interfaces/ILendingPool.sol';
@@ -558,7 +558,9 @@ contract LendingPoolConfigurator is VersionedInitializable {
    * @param decimals the decimals of the token
    **/
   function _initTokenWithProxy(address implementation, uint8 decimals) internal returns (address) {
-    InitializableAdminUpgradeabilityProxy proxy = new InitializableAdminUpgradeabilityProxy();
+
+      InitializableImmutableAdminUpgradeabilityProxy proxy
+     = new InitializableImmutableAdminUpgradeabilityProxy(address(this));
 
     bytes memory params = abi.encodeWithSignature(
       'initialize(uint8,string,string)',
@@ -567,7 +569,7 @@ contract LendingPoolConfigurator is VersionedInitializable {
       IERC20Detailed(implementation).symbol()
     );
 
-    proxy.initialize(implementation, address(this), params);
+    proxy.initialize(implementation, params);
 
     return address(proxy);
   }
@@ -577,9 +579,9 @@ contract LendingPoolConfigurator is VersionedInitializable {
     address proxyAddress,
     address implementation
   ) internal {
-    InitializableAdminUpgradeabilityProxy proxy = InitializableAdminUpgradeabilityProxy(
+
-      payable(proxyAddress)
+      InitializableImmutableAdminUpgradeabilityProxy proxy
-    );
+     = InitializableImmutableAdminUpgradeabilityProxy(payable(proxyAddress));
 
     (uint256 decimals, , , , , , , , , , ) = pool.getReserveConfigurationData(asset);
 

contracts/libraries/aave-upgradeability/BaseImmutableAdminUpgradeabilityProxy.sol

@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity ^0.6.8;
+
+import '../openzeppelin-upgradeability/BaseUpgradeabilityProxy.sol';
+
+/**
+ * @title BaseImmutableAdminUpgradeabilityProxy
+ * @author Aave, inspired by the OpenZeppelin upgradeability proxy pattern
+ * @dev This contract combines an upgradeability proxy with an authorization
+ * mechanism for administrative tasks. The admin role is stored in an immutable, which
+ * helps saving transactions costs
+ * All external functions in this contract must be guarded by the
+ * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
+ * feature proposal that would enable this to be done automatically.
+ */
+contract BaseImmutableAdminUpgradeabilityProxy is BaseUpgradeabilityProxy {
+
+  address immutable ADMIN;
+
+  constructor(address admin) public {
+     ADMIN = admin; 
+  }
+
+  modifier ifAdmin() {
+    if (msg.sender == ADMIN) {
+      _;
+    } else {
+      _fallback();
+    }
+  }
+
+  /**
+   * @return The address of the proxy admin.
+   */
+  function admin() external ifAdmin returns (address) {
+    return ADMIN;
+  }
+
+  /**
+   * @return The address of the implementation.
+   */
+  function implementation() external ifAdmin returns (address) {
+    return _implementation();
+  }
+
+  /**
+   * @dev Upgrade the backing implementation of the proxy.
+   * Only the admin can call this function.
+   * @param newImplementation Address of the new implementation.
+   */
+  function upgradeTo(address newImplementation) external ifAdmin {
+    _upgradeTo(newImplementation);
+  }
+
+  /**
+   * @dev Upgrade the backing implementation of the proxy and call a function
+   * on the new implementation.
+   * This is useful to initialize the proxied contract.
+   * @param newImplementation Address of the new implementation.
+   * @param data Data to send as msg.data in the low level call.
+   * It should include the signature and the parameters of the function to be called, as described in
+   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
+   */
+  function upgradeToAndCall(address newImplementation, bytes calldata data)
+    external
+    payable
+    ifAdmin
+  {
+    _upgradeTo(newImplementation);
+    (bool success, ) = newImplementation.delegatecall(data);
+    require(success);
+  }
+
+
+  /**
+   * @dev Only fall back when the sender is not the admin.
+   */
+  function _willFallback() internal virtual override {
+    require(msg.sender != ADMIN, 'Cannot call fallback function from the proxy admin');
+    super._willFallback();
+  }
+}

contracts/libraries/aave-upgradeability/InitializableImmutableAdminUpgradeabilityProxy.sol

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity ^0.6.8;
+
+import './BaseImmutableAdminUpgradeabilityProxy.sol';
+import '../openzeppelin-upgradeability/InitializableUpgradeabilityProxy.sol';
+
+/**
+ * @title InitializableAdminUpgradeabilityProxy
+ * @dev Extends from BaseAdminUpgradeabilityProxy with an initializer for
+ * initializing the implementation, admin, and init data.
+ */
+contract InitializableImmutableAdminUpgradeabilityProxy is
+  BaseImmutableAdminUpgradeabilityProxy,
+  InitializableUpgradeabilityProxy
+{
+
+  constructor(address admin) public BaseImmutableAdminUpgradeabilityProxy(admin) {
+  }
+
+  /**
+   * @dev Only fall back when the sender is not the admin.
+   */
+  function _willFallback() internal override(BaseImmutableAdminUpgradeabilityProxy, Proxy) {
+    BaseImmutableAdminUpgradeabilityProxy._willFallback();
+  }
+}