Added pre-EIP-2 contract creation behaviors

Added a prehomestead field on CacheDB to prevent deletion of empty
contracts that were created before HOMESTEAD as well as out-of-gas to
empty contract creation behavior.

crates/revm/src/db/in_memory_db.rs

@@ -18,7 +18,7 @@ pub type InMemoryDB = CacheDB<EmptyDB>;
 
 impl InMemoryDB {
     pub fn default() -> Self {
-        CacheDB::new(EmptyDB {})
+        CacheDB::new(EmptyDB {}, false)
     }
 }
 
@@ -32,6 +32,7 @@ pub struct CacheDB<ExtDB: DatabaseRef> {
     pub logs: Vec<Log>,
     pub block_hashes: Map<U256, H256>,
     pub db: ExtDB,
+    pub prehomestead: bool,
 }
 
 #[derive(Debug, Clone, Default)]
@@ -55,7 +56,7 @@ pub enum AccountState {
 }
 
 impl<ExtDB: DatabaseRef> CacheDB<ExtDB> {
-    pub fn new(db: ExtDB) -> Self {
+    pub fn new(db: ExtDB, prehomestead: bool) -> Self {
         let mut contracts = Map::new();
         contracts.insert(KECCAK_EMPTY, Bytes::new());
         contracts.insert(H256::zero(), Bytes::new());
@@ -65,6 +66,7 @@ impl<ExtDB: DatabaseRef> CacheDB<ExtDB> {
             logs: Vec::default(),
             block_hashes: Map::new(),
             db,
+            prehomestead,
         }
     }
 
@@ -102,6 +104,13 @@ impl<ExtDB: DatabaseRef> DatabaseCommit for CacheDB<ExtDB> {
     fn commit(&mut self, changes: Map<H160, Account>) {
         for (add, acc) in changes {
             if acc.is_empty() || matches!(acc.filth, Filth::Destroyed) {
+                // pre EIP-2
+                if acc.info.code.is_some()
+                    && acc.info.code_hash == KECCAK_EMPTY
+                    && self.prehomestead
+                {
+                    continue;
+                }
                 // clear account data, and increate its incarnation.
                 let acc = self.accounts.entry(add).or_default();
                 acc.account_state = AccountState::EVMStorageCleared;

crates/revm/src/evm_impl.rs

@@ -415,8 +415,22 @@ impl<'a, GSPEC: Spec, DB: Database, const INSPECT: bool> EVMImpl<'a, GSPEC, DB,
                     let gas_for_code = code.len() as u64 * crate::gas::CODEDEPOSIT;
                     // record code deposit gas cost and check if we are out of gas.
                     if !interp.gas.record_cost(gas_for_code) {
-                        self.data.subroutine.checkpoint_revert(checkpoint);
-                        return (Return::OutOfGas, ret, interp.gas, b);
+                        // EIP-2
+                        if SPEC::enabled(HOMESTEAD) {
+                            self.data.subroutine.checkpoint_revert(checkpoint);
+                            return (Return::OutOfGas, ret, interp.gas, b);
+                        } else {
+                            self.data.subroutine.checkpoint_commit();
+                            let empty_contract = Bytes::new();
+                            let code_hash =
+                                H256::from_slice(Keccak256::digest(&empty_contract).as_slice());
+                            self.data.subroutine.set_code(
+                                created_address,
+                                empty_contract,
+                                code_hash,
+                            );
+                            return (Return::Continue, ret, interp.gas, b);
+                        }
                     }
                 }
                 // if we have enought gas