Making contracts memory-safe

.solcover.js

@@ -12,4 +12,11 @@ module.exports = {
         grep: "@skip-on-coverage", // Find everything with this tag
         invert: true, // Run the grep's inverse set.
     },
+    configureYulOptimizer: true,
+    solcOptimizerDetails: {
+        yul: true,
+        yulDetails: {
+            optimizerSteps: ""
+        },
+    },
 };

contracts/Safe.sol

@@ -263,7 +263,7 @@ contract Safe is
         uint256 contractSignatureLen;
         /* solhint-disable no-inline-assembly */
         /// @solidity memory-safe-assembly
-        assembly {
+        assembly ("memory-safe") {
             contractSignatureLen := mload(add(add(signatures, offset), 0x20))
         }
         /* solhint-enable no-inline-assembly */
@@ -273,7 +273,7 @@ contract Safe is
         bytes memory contractSignature;
         /* solhint-disable no-inline-assembly */
         /// @solidity memory-safe-assembly
-        assembly {
+        assembly ("memory-safe") {
             // The signature data for contract signatures is appended to the concatenated signatures and the offset is stored in s
             contractSignature := add(add(signatures, offset), 0x20)
         }

contracts/base/Executor.sol

@@ -28,7 +28,7 @@ abstract contract Executor {
         if (operation == Enum.Operation.DelegateCall) {
             /* solhint-disable no-inline-assembly */
             /// @solidity memory-safe-assembly
-            assembly {
+            assembly ("memory-safe") {
                 success := delegatecall(txGas, to, add(data, 0x20), mload(data), 0, 0)
             }
             /* solhint-enable no-inline-assembly */

contracts/base/FallbackManager.sol

@@ -36,7 +36,7 @@ abstract contract FallbackManager is SelfAuthorized {
         bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
         /* solhint-disable no-inline-assembly */
         /// @solidity memory-safe-assembly
-        assembly {
+        assembly ("memory-safe") {
             sstore(slot, handler)
         }
         /* solhint-enable no-inline-assembly */

contracts/base/ModuleManager.sol

@@ -183,7 +183,7 @@ abstract contract ModuleManager is SelfAuthorized, Executor, GuardManager {
         // Set correct size of returned array
         /* solhint-disable no-inline-assembly */
         /// @solidity memory-safe-assembly
-        assembly {
+        assembly ("memory-safe") {
             mstore(array, moduleCount)
         }
         /* solhint-enable no-inline-assembly */

contracts/common/SecuredTokenTransfer.sol

@@ -18,8 +18,9 @@ abstract contract SecuredTokenTransfer {
     function transferToken(address token, address receiver, uint256 amount) internal returns (bool transferred) {
         // 0xa9059cbb - keccack("transfer(address,uint256)")
         bytes memory data = abi.encodeWithSelector(0xa9059cbb, receiver, amount);
-        // solhint-disable-next-line no-inline-assembly
-        assembly {
+        /* solhint-disable no-inline-assembly */
+        /// @solidity memory-safe-assembly
+        assembly ("memory-safe") {
             // We write the return value to scratch space.
             // See https://docs.soliditylang.org/en/v0.7.6/internals/layout_in_memory.html#layout-in-memory
             let success := call(sub(gas(), 10000), token, 0, add(data, 0x20), mload(data), 0, 0x20)
@@ -34,5 +35,6 @@ abstract contract SecuredTokenTransfer {
                 transferred := 0
             }
         }
+        /* solhint-enable no-inline-assembly */
     }
 }

contracts/common/SignatureDecoder.sol

@@ -21,7 +21,7 @@ abstract contract SignatureDecoder {
     function signatureSplit(bytes memory signatures, uint256 pos) internal pure returns (uint8 v, bytes32 r, bytes32 s) {
         /* solhint-disable no-inline-assembly */
         /// @solidity memory-safe-assembly
-        assembly {
+        assembly ("memory-safe") {
             let signaturePos := mul(0x41, pos)
             r := mload(add(signatures, add(signaturePos, 0x20)))
             s := mload(add(signatures, add(signaturePos, 0x40)))

contracts/common/StorageAccessible.sol

@@ -19,7 +19,7 @@ abstract contract StorageAccessible {
         for (uint256 index = 0; index < length; index++) {
             /* solhint-disable no-inline-assembly */
             /// @solidity memory-safe-assembly
-            assembly {
+            assembly ("memory-safe") {
                 let word := sload(add(offset, index))
                 mstore(add(add(result, 0x20), mul(index, 0x20)), word)
             }
@@ -42,7 +42,7 @@ abstract contract StorageAccessible {
     function simulateAndRevert(address targetContract, bytes memory calldataPayload) external {
         /* solhint-disable no-inline-assembly */
         /// @solidity memory-safe-assembly
-        assembly {
+        assembly ("memory-safe") {
             let success := delegatecall(gas(), targetContract, add(calldataPayload, 0x20), mload(calldataPayload), 0, 0)
             // Load free memory location
             let ptr := mload(0x40)

contracts/interfaces/ViewStorageAccessible.sol

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LGPL-3.0-only
 pragma solidity >=0.5.0 <0.9.0;
 
 /// @title ViewStorageAccessible - Interface on top of StorageAccessible base class to allow simulations from view functions.

contracts/libraries/Safe130To141Migration.sol

@@ -125,10 +125,12 @@ contract Safe130To141Migration is SafeStorage {
      */
     function isContract(address account) internal view returns (bool) {
         uint256 size;
-        // solhint-disable-next-line no-inline-assembly
+        /* solhint-disable no-inline-assembly */
+        /// @solidity memory-safe-assembly
         assembly {
             size := extcodesize(account)
         }
+        /* solhint-enable no-inline-assembly */
 
         // If the code size is greater than 0, it is a contract; otherwise, it is an EOA.
         return size > 0;

contracts/libraries/Safe150Migration.sol

@@ -160,10 +160,12 @@ contract Safe150Migration is SafeStorage {
      */
     function getGuard() internal view returns (address guard) {
         bytes32 slot = GUARD_STORAGE_SLOT;
-        // solhint-disable-next-line no-inline-assembly
+        /* solhint-disable no-inline-assembly */
+        /// @solidity memory-safe-assembly
         assembly {
             guard := sload(slot)
         }
+        /* solhint-enable no-inline-assembly */
     }
 
     /**
@@ -176,10 +178,12 @@ contract Safe150Migration is SafeStorage {
      */
     function isContract(address account) internal view returns (bool) {
         uint256 size;
-        // solhint-disable-next-line no-inline-assembly
+        /* solhint-disable no-inline-assembly */
+        /// @solidity memory-safe-assembly
         assembly {
             size := extcodesize(account)
         }
+        /* solhint-enable no-inline-assembly */
 
         // If the code size is greater than 0, it is a contract; otherwise, it is an EOA.
         return size > 0;

contracts/libraries/SafeToL2Migration.sol

@@ -96,7 +96,7 @@ contract SafeToL2Migration is SafeStorage {
             0,
             0,
             address(0),
-            address(0),
+            payable(address(0)),
             "", // We cannot detect signatures
             additionalInfo
         );
@@ -166,10 +166,12 @@ contract SafeToL2Migration is SafeStorage {
      */
     function isContract(address account) internal view returns (bool) {
         uint256 size;
-        // solhint-disable-next-line no-inline-assembly
+        /* solhint-disable no-inline-assembly */
+        /// @solidity memory-safe-assembly
         assembly {
             size := extcodesize(account)
         }
+        /* solhint-enable no-inline-assembly */
 
         // If the code size is greater than 0, it is a contract; otherwise, it is an EOA.
         return size > 0;

contracts/proxies/SafeProxy.sol

@@ -31,21 +31,26 @@ contract SafeProxy {
 
     /// @dev Fallback function forwards all transactions and returns all received return data.
     fallback() external payable {
-        // solhint-disable-next-line no-inline-assembly
+        /* solhint-disable no-inline-assembly */
+        /// @solidity memory-safe-assembly
         assembly {
             let _singleton := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
+            let ptr := mload(0x40)
             // 0xa619486e == keccak("masterCopy()"). The value is right padded to 32-bytes with 0s
             if eq(calldataload(0), 0xa619486e00000000000000000000000000000000000000000000000000000000) {
-                mstore(0, _singleton)
-                return(0, 0x20)
+                mstore(ptr, _singleton)
+                return(ptr, 0x20)
             }
-            calldatacopy(0, 0, calldatasize())
-            let success := delegatecall(gas(), _singleton, 0, calldatasize(), 0, 0)
-            returndatacopy(0, 0, returndatasize())
+            ptr := mload(0x40)
+            calldatacopy(ptr, 0, calldatasize())
+            let success := delegatecall(gas(), _singleton, ptr, calldatasize(), 0, 0)
+            ptr := mload(0x40)
+            returndatacopy(ptr, 0, returndatasize())
             if eq(success, 0) {
-                revert(0, returndatasize())
+                revert(ptr, returndatasize())
             }
-            return(0, returndatasize())
+            return(ptr, returndatasize())
         }
+        /* solhint-enable no-inline-assembly */
     }
 }

contracts/test/DelegateCaller.sol

@@ -13,12 +13,15 @@ contract DelegateCaller {
     function makeDelegatecall(address _called, bytes memory _calldata) external returns (bool success, bytes memory returnData) {
         (success, returnData) = _called.delegatecall(_calldata);
         if (!success) {
-            // solhint-disable-next-line no-inline-assembly
+            /* solhint-disable no-inline-assembly */
+            /// @solidity memory-safe-assembly
             assembly {
+                let ptr := mload(0x40)
                 let length := returndatasize()
-                returndatacopy(0, 0, length)
-                revert(0, length)
+                returndatacopy(ptr, 0, length)
+                revert(ptr, length)
             }
+            /* solhint-enable no-inline-assembly */
         }
     }
 }

docs/guidelines.md

@@ -11,6 +11,7 @@ The data can be stored to this location with
 ```
 bytes32 slot = VARIABLE_SLOT;
 // solhint-disable-next-line no-inline-assembly
+/// @solidity memory-safe-assembly
 assembly {
     sstore(slot, value)
 }
@@ -21,6 +22,7 @@ and read with
 ```
 bytes32 slot = VARIABLE_SLOT;
 // solhint-disable-next-line no-inline-assembly
+/// @solidity memory-safe-assembly
 assembly {
     value := sload(slot)
 }

hardhat.config.ts

@@ -39,8 +39,10 @@ import "./src/tasks/show_codesize";
 import { BigNumber } from "@ethersproject/bignumber";
 import { DeterministicDeploymentInfo } from "hardhat-deploy/dist/types";
 
-const primarySolidityVersion = SOLIDITY_VERSION || "0.7.6";
-const soliditySettings = SOLIDITY_SETTINGS ? JSON.parse(SOLIDITY_SETTINGS) : undefined;
+const primarySolidityVersion = SOLIDITY_VERSION || "0.8.19";
+const soliditySettings = SOLIDITY_SETTINGS
+    ? JSON.parse(SOLIDITY_SETTINGS)
+    : JSON.parse('{"viaIR":true,"optimizer":{"enabled":true, "details": {"yul": true}}}');
 
 const deterministicDeployment = (network: string): DeterministicDeploymentInfo => {
     const info = getSingletonFactoryInfo(parseInt(network));
@@ -70,7 +72,12 @@ const userConfig: HardhatUserConfig = {
         target: "ethers-v6",
     },
     solidity: {
-        compilers: [{ version: primarySolidityVersion, settings: soliditySettings }, { version: "0.6.12" }, { version: "0.5.17" }],
+        compilers: [
+            { version: primarySolidityVersion, settings: soliditySettings },
+            { version: "0.7.6" },
+            { version: "0.6.12" },
+            { version: "0.5.17" },
+        ],
     },
     networks: {
         hardhat: {

package.json

@@ -29,6 +29,7 @@
         "lint:sol:prettier": "prettier 'contracts/**/*.sol' --list-different",
         "lint:ts": "eslint 'src/**/*.ts' 'test/**/*.ts' --fix",
         "lint:ts:prettier": "prettier 'src/**/*.ts' 'test/**/*.ts' --list-different",
+        "fmt": "npm run fmt:sol && npm run fmt:ts",
         "fmt:sol": "prettier 'contracts/**/*.sol' -w",
         "fmt:ts": "prettier 'src/**/*.ts' 'test/**/*.ts' -w",
         "prepack": "npm run build",
@@ -70,7 +71,7 @@
         "husky": "^8.0.3",
         "prettier": "^3.1.0",
         "prettier-plugin-solidity": "^1.2.0",
-        "solc": "0.7.6",
+        "solc": "0.8.19",
         "solhint": "^4.0.0",
         "ts-node": "^10.9.1",
         "typescript": "^5.3.2",

test/accessors/SimulateTxAccessor.spec.ts

@@ -65,7 +65,7 @@ describe("SimulateTxAccessor", () => {
             const simulation = accessor.interface.decodeFunctionResult("simulate", acccessibleData);
             expect(safe.interface.decodeFunctionResult("getOwners", simulation.returnData)[0]).to.be.deep.eq([user1.address]);
             expect(simulation.success).to.be.true;
-            expect(simulation.estimate).to.be.lte(10000n);
+            expect(simulation.estimate).to.be.lte(14800n);
         });
 
         it("simulate delegatecall", async () => {
@@ -83,7 +83,7 @@ describe("SimulateTxAccessor", () => {
                 userBalance + ethers.parseEther("1"),
             );
             expect(simulation.success).to.be.true;
-            expect(simulation.estimate).to.be.lte(15000n);
+            expect(simulation.estimate).to.be.lte(15100n);
         });
 
         it("simulate selfdestruct", async () => {