Merge pull request #43 from matter-labs/vb-implement-optimisations-fo…

…r-validator-timelock

Implement optimisations for validator timelock

ethereum/contracts/zksync/ValidatorTimelock.sol

@@ -3,6 +3,7 @@
 pragma solidity ^0.8.13;
 
 import "@openzeppelin/contracts/access/Ownable2Step.sol";
+import "./libraries/LibMap.sol";
 import "./interfaces/IExecutor.sol";
 
 /// @author Matter Labs
@@ -17,6 +18,8 @@ import "./interfaces/IExecutor.sol";
 /// the timestamp is stored for it. Later, when the owner calls the batch execution, the contract checks that batch
 /// was committed not earlier than X time ago.
 contract ValidatorTimelock is IExecutor, Ownable2Step {
+    using LibMap for LibMap.Uint32Map;
+
     /// @dev Part of the IBase interface. Not used in this contract.
     string public constant override getName = "ValidatorTimelock";
 
@@ -29,16 +32,16 @@ contract ValidatorTimelock is IExecutor, Ownable2Step {
     /// @dev The main zkSync smart contract.
     address public immutable zkSyncContract;
 
-    /// @dev The mapping of L2 batch number => timestamp when it was commited.
-    mapping(uint256 => uint256) public committedBatchTimestamp;
+    /// @dev The mapping of L2 batch number => timestamp when it was committed.
+    LibMap.Uint32Map committedBatchTimestamp;
 
     /// @dev The address that can commit/revert/validate/execute batches.
     address public validator;
 
     /// @dev The delay between committing and executing batches.
-    uint256 public executionDelay;
+    uint32 public executionDelay;
 
-    constructor(address _initialOwner, address _zkSyncContract, uint256 _executionDelay, address _validator) {
+    constructor(address _initialOwner, address _zkSyncContract, uint32 _executionDelay, address _validator) {
         _transferOwnership(_initialOwner);
         zkSyncContract = _zkSyncContract;
         executionDelay = _executionDelay;
@@ -53,7 +56,7 @@ contract ValidatorTimelock is IExecutor, Ownable2Step {
     }
 
     /// @dev Set the delay between committing and executing batches.
-    function setExecutionDelay(uint256 _executionDelay) external onlyOwner {
+    function setExecutionDelay(uint32 _executionDelay) external onlyOwner {
         executionDelay = _executionDelay;
         emit NewExecutionDelay(_executionDelay);
     }
@@ -64,14 +67,24 @@ contract ValidatorTimelock is IExecutor, Ownable2Step {
         _;
     }
 
+    /// @dev Returns the timestamp when `_l2BatchNumber` was committed.
+    function getCommittedBatchTimestamp(uint256 _l2BatchNumber) external view returns (uint256) {
+        return committedBatchTimestamp.get(_l2BatchNumber);
+    }
+
     /// @dev Records the timestamp for all provided committed batches and make
     /// a call to the zkSync contract with the same calldata.
     function commitBatches(
         StoredBatchInfo calldata,
         CommitBatchInfo[] calldata _newBatchesData
     ) external onlyValidator {
-        for (uint256 i = 0; i < _newBatchesData.length; ++i) {
-            committedBatchTimestamp[_newBatchesData[i].batchNumber] = block.timestamp;
+        unchecked {
+            // This contract is only a temporary solution, that hopefully will be disabled until 2106 year, so...
+            // It is safe to cast.
+            uint32 timestamp = uint32(block.timestamp);
+            for (uint256 i = 0; i < _newBatchesData.length; ++i) {
+                committedBatchTimestamp.set(_newBatchesData[i].batchNumber, timestamp);
+            }
         }
 
         _propagateToZkSync();
@@ -98,15 +111,17 @@ contract ValidatorTimelock is IExecutor, Ownable2Step {
     /// @dev Check that batches were committed at least X time ago and
     /// make a call to the zkSync contract with the same calldata.
     function executeBatches(StoredBatchInfo[] calldata _newBatchesData) external onlyValidator {
-        for (uint256 i = 0; i < _newBatchesData.length; ++i) {
-            uint256 commitBatchTimestamp = committedBatchTimestamp[_newBatchesData[i].batchNumber];
-
-            // Note: if the `commitBatchTimestamp` is zero, that means either:
-            // * The batch was committed, but not though this contract.
-            // * The batch wasn't committed at all, so execution will fail in the zkSync contract.
-            // We allow executing such batches.
-
-            require(block.timestamp > commitBatchTimestamp + executionDelay, "5c"); // The delay is not passed
+        uint256 delay = executionDelay; // uint32
+        unchecked {
+            for (uint256 i = 0; i < _newBatchesData.length; ++i) {
+                uint256 commitBatchTimestamp = committedBatchTimestamp.get(_newBatchesData[i].batchNumber);
+
+                // Note: if the `commitBatchTimestamp` is zero, that means either:
+                // * The batch was committed, but not through this contract.
+                // * The batch wasn't committed at all, so execution will fail in the zkSync contract.
+                // We allow executing such batches.
+                require(block.timestamp >= commitBatchTimestamp + delay, "5c"); // The delay is not passed
+            }
         }
 
         _propagateToZkSync();

ethereum/contracts/zksync/libraries/LibMap.sol

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.13;
+
+/// @notice Library for storage of packed unsigned integers.
+/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/LibMap.sol)
+library LibMap {
+    /// @dev A uint32 map in storage.
+    struct Uint32Map {
+        mapping(uint256 => uint256) map;
+    }
+
+    /// @dev Retrieves the uint32 value at a specific index from the Uint32Map.
+    /// @param _map The Uint32Map instance containing the packed uint32 values.
+    /// @param _index The index of the uint32 value to retrieve.
+    /// @return result The uint32 value at the specified index.
+    function get(Uint32Map storage _map, uint256 _index) internal view returns (uint32 result) {
+        unchecked {
+            // Each storage slot can store 256 bits of data.
+            // As uint32 is 32 bits long, 8 uint32s can be packed into one storage slot.
+            // Hence, `_index / 8` is done to find the storage slot that contains the required uint32.
+            uint256 mapValue = _map.map[_index / 8];
+
+            // First three bits of the original `_index` denotes the position of the uint32 in that slot.
+            // So, '(_index & 7) * 32' is done to find the bit position of the uint32 in that storage slot.
+            uint256 bitOffset = (_index & 7) * 32;
+
+            // Shift the bits to the right and retrieve the uint32 value.
+            result = uint32(mapValue >> bitOffset);
+        }
+    }
+
+    /// @dev Updates the uint32 value at `_index` in `map`.
+    /// @param _map The Uint32Map instance containing the packed uint32 values.
+    /// @param _index The index of the uint32 value to retrieve.
+    /// @param _value The new value at the specified index.
+    function set(
+        Uint32Map storage _map,
+        uint256 _index,
+        uint32 _value
+    ) internal {
+        unchecked {
+            // Each storage slot can store 256 bits of data.
+            // As uint32 is 32 bits long, 8 uint32s can be packed into one storage slot.
+            // Hence, `_index / 8` is done to find the storage slot that contains the required uint32.
+            uint256 mapIndex = _index / 8;
+            uint256 mapValue = _map.map[mapIndex];
+
+            // First three bits of the original `_index` denotes the position of the uint32 in that slot.
+            // So, '(_index & 7) * 32' is done to find the bit position of the uint32 in that storage slot.
+            uint256 bitOffset = (_index & 7) * 32;
+
+            // XORing a value A with B, and then with A again, gives the original value B.
+            // We will use this property to update the uint32 value in the slot.
+
+            // Shift the bits to the right and retrieve the uint32 value.
+            uint32 oldValue = uint32(mapValue >> bitOffset);
+
+            // Calculate the XOR of the new value and the existing value.
+            uint256 newValueXorOldValue = uint256(oldValue ^ _value);
+
+            // Finally, we XOR the slot with the XOR of the new value and the existing value,
+            // shifted to its proper position. The XOR operation will effectively replace the old value with the new value.
+            _map.map[mapIndex] = (newValueXorOldValue << bitOffset) ^ mapValue;
+        }
+    }
+}

ethereum/package.json

@@ -53,7 +53,7 @@
     "test:foundry": "hardhat solpp && forge test",
     "test:fork": "CONTRACT_TESTS=1 TEST_CONTRACTS_FORK=1 yarn run hardhat test test/unit_tests/*.fork.ts --network hardhat",
     "lint": "yarn lint:sol && yarn prettier:check",
-    "lint:sol-contracts": "solhint --max-warnings 30 contracts/**/*.sol",
+    "lint:sol-contracts": "solhint --max-warnings 31 contracts/**/*.sol",
     "lint:sol-tests": "solhint --max-warnings 0 test/**/*.sol",
     "lint:sol": "yarn lint:sol-contracts && yarn lint:sol-tests",
     "prettier:check-contracts": "prettier --check contracts/**/*.sol",

ethereum/test/unit_tests/validator_timelock_test.spec.ts

@@ -157,7 +157,7 @@ describe(`ValidatorTimelock tests`, function () {
     });
 
     it(`Should successfully overwrite the committing timestamp on the reverted batches timestamp`, async () => {
-        const revertedBatchesTimestamp = Number(await validatorTimelock.committedBatchTimestamp(1));
+        const revertedBatchesTimestamp = Number(await validatorTimelock.getCommittedBatchTimestamp(1));
 
         await validatorTimelock
             .connect(validator)
@@ -167,7 +167,7 @@ describe(`ValidatorTimelock tests`, function () {
             .connect(validator)
             .proveBatches(getMockStoredBatchInfo(0), [getMockStoredBatchInfo(1)], MOCK_PROOF_INPUT);
 
-        const newBatchesTimestamp = Number(await validatorTimelock.committedBatchTimestamp(1));
+        const newBatchesTimestamp = Number(await validatorTimelock.getCommittedBatchTimestamp(1));
 
         expect(newBatchesTimestamp).greaterThanOrEqual(revertedBatchesTimestamp);
     });

ethereum/yarn.lock

@@ -904,7 +904,7 @@
   resolved "https://registry.yarnpkg.com/@sindresorhus/is/-/is-4.6.0.tgz#3c7c9c46e678feefe7a2e5bb609d3dbd665ffb3f"
   integrity sha512-t09vSN3MdfsyCHoFcTRCH/iUtG7OJ0CsjzB8cjAmKc/va/kIgeDI/TxsigdncE/4be734m0cvIYwNaV4i2XqAw==
 
-"@solidity-parser/parser@^0.14.0", "@solidity-parser/parser@^0.14.1":
+"@solidity-parser/parser@^0.14.0":
   version "0.14.5"
   resolved "https://registry.yarnpkg.com/@solidity-parser/parser/-/parser-0.14.5.tgz#87bc3cc7b068e08195c219c91cd8ddff5ef1a804"
   integrity sha512-6dKnHZn7fg/iQATVEzqyUOyEidbn05q7YA2mQ9hC0MMXhhV3/JrsxmFSYZAcr7j1yUP700LLhTruvJ3MiQmjJg==
@@ -6979,7 +6979,7 @@ [email protected]:
     object.getownpropertydescriptors "^2.0.3"
     semver "^5.7.0"
 
-node-fetch@^2.6.0, node-fetch@^2.6.1, node-fetch@^2.6.7:
+node-fetch@^2.6.1, node-fetch@^2.6.7:
   version "2.6.7"
   resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.6.7.tgz#24de9fba827e3b4ae44dc8b20256a379160052ad"
   integrity sha512-ZjMPFEfVx5j+y2yF35Kzx5sF7kDzxuDj6ziH4FFbOp87zKDZNx8yExJIb05OGF4Nlt9IHFIMBkRl41VdvcNdbQ==
@@ -7011,13 +7011,6 @@ [email protected]:
   dependencies:
     abbrev "1"
 
-[email protected]:
-  version "3.0.6"
-  resolved "https://registry.yarnpkg.com/nopt/-/nopt-3.0.6.tgz#c6465dbf08abcd4db359317f79ac68a646b28ff9"
-  integrity sha512-4GUt3kSEYmk4ITxzB/b9vaIDfUVWN/Ml1Fwl11IlnIG2iaJ9O6WXZ9SrYM9NLI8OCBieN2Y8SWC2oJV0RQ7qYg==
-  dependencies:
-    abbrev "1"
-
 normalize-package-data@^2.3.2:
   version "2.5.0"
   resolved "https://registry.yarnpkg.com/normalize-package-data/-/normalize-package-data-2.5.0.tgz#e66db1838b200c1dfc233225d12cb36520e234a8"
@@ -8233,7 +8226,7 @@ semaphore@>=1.0.1, semaphore@^1.0.3, semaphore@^1.1.0:
   resolved "https://registry.yarnpkg.com/semaphore/-/semaphore-1.1.0.tgz#aaad8b86b20fe8e9b32b16dc2ee682a8cd26a8aa"
   integrity sha512-O4OZEaNtkMd/K0i6js9SL+gqy0ZCBMgUvlSqHKi4IBdjhe7wB8pwztUk1BbZ1fmrvpwFrPbHzqd2w5pTcJH6LA==
 
-"semver@2 || 3 || 4 || 5", semver@^5.3.0, semver@^5.5.0, semver@^5.6.0, semver@^5.7.0:
+"semver@2 || 3 || 4 || 5", semver@^5.3.0, semver@^5.5.0, semver@^5.6.0:
   version "5.7.1"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.7.1.tgz#a954f931aeba508d307bbf069eff0c01c96116f7"
   integrity sha512-sauaDf/PZdVgrLTNYHRtpXa1iRiKcaebiKQ1BJdpQlWH2lCvexQdX55snPFyK7QzpudqbCI0qXFfOasHdyNDGQ==
@@ -8248,14 +8241,7 @@ semver@^6.3.0:
   resolved "https://registry.yarnpkg.com/semver/-/semver-6.3.0.tgz#ee0a64c8af5e8ceea67687b133761e1becbd1d3d"
   integrity sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==
 
-semver@^7.3.4:
-  version "7.5.4"
-  resolved "https://registry.yarnpkg.com/semver/-/semver-7.5.4.tgz#483986ec4ed38e1c6c48c34894a9182dbff68a6e"
-  integrity sha512-1bCSESV6Pv+i21Hvpxp3Dx+pSD8lIPt8uVjRrxAUt/nbswYc+tK6Y2btiULjd4+fnq15PX+nqQDC7Oft7WkwcA==
-  dependencies:
-    lru-cache "^6.0.0"
-
-semver@^7.3.8, semver@^7.5.2:
+semver@^7.3.4, semver@^7.3.8, semver@^7.5.2:
   version "7.5.4"
   resolved "https://registry.yarnpkg.com/semver/-/semver-7.5.4.tgz#483986ec4ed38e1c6c48c34894a9182dbff68a6e"
   integrity sha512-1bCSESV6Pv+i21Hvpxp3Dx+pSD8lIPt8uVjRrxAUt/nbswYc+tK6Y2btiULjd4+fnq15PX+nqQDC7Oft7WkwcA==