feat: cool cheatcode (foundry-rs#5830)

* feat: `cool` cheatcode

* refactor: extract to a function, remove check

crates/abi/abi/HEVM.sol

@@ -22,6 +22,7 @@ fee(uint256)
 coinbase(address)
 store(address,bytes32,bytes32)
 load(address,bytes32)(bytes32)
+cool(address)
 
 setEnv(string,string)
 envBool(string)(bool)

crates/evm/src/executor/inspector/cheatcodes/env.rs

@@ -318,6 +318,18 @@ fn add_breakpoint(state: &mut Cheatcodes, caller: Address, inner: &str, add: boo
     Ok(Bytes::new())
 }
 
+// mark the slots of an account and the account address as cold
+fn cool_account<DB: DatabaseExt>(data: &mut EVMData<'_, DB>, address: Address) -> Result {
+    if let Some(account) = data.journaled_state.state.get_mut(&h160_to_b160(address)) {
+        if account.is_touched() {
+            account.unmark_touch();
+        }
+        account.storage.clear();
+    }
+
+    Ok(Bytes::new())
+}
+
 #[instrument(level = "error", name = "env", target = "evm::cheatcodes", skip_all)]
 pub fn apply<DB: DatabaseExt>(
     state: &mut Cheatcodes,
@@ -387,6 +399,7 @@ pub fn apply<DB: DatabaseExt>(
             )?;
             ru256_to_u256(val).encode().into()
         }
+        HEVMCalls::Cool(inner) => cool_account(data, inner.0)?,
         HEVMCalls::Breakpoint0(inner) => add_breakpoint(state, caller, &inner.0, true)?,
         HEVMCalls::Breakpoint1(inner) => add_breakpoint(state, caller, &inner.0, inner.1)?,
         HEVMCalls::Etch(inner) => {

testdata/cheats/Cool.t.sol

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: Unlicense
+pragma solidity 0.8.18;
+
+import "../lib/ds-test/src/test.sol";
+import "./Vm.sol";
+
+contract CoolTest is DSTest {
+    Vm constant vm = Vm(HEVM_ADDRESS);
+    uint256 public slot0 = 1;
+
+    function testCool_SLOAD_normal() public {
+        uint256 startGas;
+        uint256 endGas;
+        uint256 val;
+        uint256 beforeCoolGas;
+        uint256 noCoolGas;
+
+        startGas = gasleft();
+        val = slot0;
+        endGas = gasleft();
+        beforeCoolGas = startGas - endGas;
+
+        startGas = gasleft();
+        val = slot0;
+        endGas = gasleft();
+        noCoolGas = startGas - endGas;
+
+        assertGt(beforeCoolGas, noCoolGas);
+    }
+
+    function testCool_SLOAD() public {
+        uint256 startGas;
+        uint256 endGas;
+        uint256 val;
+        uint256 beforeCoolGas;
+        uint256 afterCoolGas;
+        uint256 noCoolGas;
+
+        startGas = gasleft();
+        val = slot0;
+        endGas = gasleft();
+        beforeCoolGas = startGas - endGas;
+
+        vm.cool(address(this));
+
+        startGas = gasleft();
+        val = slot0;
+        endGas = gasleft();
+        afterCoolGas = startGas - endGas;
+
+        assertEq(beforeCoolGas, afterCoolGas);
+
+        startGas = gasleft();
+        val = slot0;
+        endGas = gasleft();
+        noCoolGas = startGas - endGas;
+
+        assertGt(beforeCoolGas, noCoolGas);
+    }
+}

testdata/cheats/Vm.sol

@@ -96,6 +96,9 @@ interface Vm {
     // Stores a value to an address' storage slot, (who, slot, value)
     function store(address, bytes32, bytes32) external;
 
+    // Cools off a warm address and its storage slots
+    function cool(address) external;
+
     // Signs data, (privateKey, digest) => (v, r, s)
     function sign(uint256, bytes32) external returns (uint8, bytes32, bytes32);