feat(levm): add in memory db for AccountUpdates

crates/vm/backends/levm/mod.rs

@@ -164,8 +164,11 @@ impl LEVM {
     ) -> Result<Vec<AccountUpdate>, EvmError> {
         let mut account_updates: Vec<AccountUpdate> = vec![];
         for (address, new_state_account) in db.cache.drain() {
-            let initial_state_account = db.store.get_account(address)?;
-            let account_existed = db.store.account_exists(address);
+            let initial_state_account = db
+                .in_memory_db
+                .get(&address)
+                .cloned()
+                .unwrap_or(db.store.get_account(address)?);
 
             let mut acc_info_updated = false;
             let mut storage_updated = false;
@@ -206,15 +209,16 @@ impl LEVM {
 
             // https://eips.ethereum.org/EIPS/eip-161
             if fork >= Fork::SpuriousDragon {
-                // "No account may change state from non-existent to existent-but-_empty_. If an operation would do this, the account SHALL instead remain non-existent."
-                if !account_existed && new_state_account.is_empty() {
-                    continue;
-                }
-
                 // "At the end of the transaction, any account touched by the execution of that transaction which is now empty SHALL instead become non-existent (i.e. deleted)."
                 // Note: An account can be empty but still exist in the trie (if that's the case we remove it)
                 if new_state_account.is_empty() {
                     removed = true;
+
+                    // "No account may change state from non-existent to existent-but-_empty_. If an operation would do this, the account SHALL instead remain non-existent."
+                    let account_existed = db.store.account_exists(address);
+                    if !account_existed {
+                        continue;
+                    }
                 }
             }
 
@@ -233,6 +237,7 @@ impl LEVM {
 
             account_updates.push(account_update);
         }
+        db.in_memory_db.clear();
         Ok(account_updates)
     }
 

crates/vm/levm/src/db/gen_db.rs

@@ -1,3 +1,4 @@
+use std::collections::HashMap;
 use std::sync::Arc;
 
 use bytes::Bytes;
@@ -21,11 +22,16 @@ use super::Database;
 pub struct GeneralizedDatabase {
     pub store: Arc<dyn Database>,
     pub cache: CacheDB,
+    pub in_memory_db: HashMap<Address, Account>,
 }
 
 impl GeneralizedDatabase {
     pub fn new(store: Arc<dyn Database>, cache: CacheDB) -> Self {
-        Self { store, cache }
+        Self {
+            store,
+            cache,
+            in_memory_db: HashMap::new(),
+        }
     }
 
     // ================== Account related functions =====================
@@ -35,18 +41,49 @@ impl GeneralizedDatabase {
         match cache::get_account(&self.cache, &address) {
             Some(acc) => Ok(acc.clone()),
             None => {
-                let account = self.store.get_account(address)?;
+                let account = self.get_account_from_database(address)?;
                 cache::insert_account(&mut self.cache, address, account.clone());
                 Ok(account)
             }
         }
     }
 
+    /// Gets account from storage, storing in InMemoryDB for efficiency when getting AccountUpdates.
+    pub fn get_account_from_database(
+        &mut self,
+        address: Address,
+    ) -> Result<Account, DatabaseError> {
+        let account = self.store.get_account(address)?;
+        self.in_memory_db.insert(address, account.clone());
+        Ok(account)
+    }
+
+    /// Gets storage slot from Database, storing in InMemoryDB for efficiency when getting AccountUpdates.
+    pub fn get_value_from_database(
+        &mut self,
+        address: Address,
+        key: H256,
+    ) -> Result<U256, DatabaseError> {
+        let value = self.store.get_storage_value(address, key)?;
+        // Account must be already in in_memory_db
+        if let Some(account) = self.in_memory_db.get_mut(&address) {
+            account.storage.insert(key, value);
+        } else {
+            return Err(DatabaseError::Custom(
+                "Account not found in InMemoryDB".to_string(),
+            ));
+        }
+        Ok(value)
+    }
+
     /// Gets account without pushing it to the cache
-    pub fn get_account_no_push_cache(&self, address: Address) -> Result<Account, DatabaseError> {
+    pub fn get_account_no_push_cache(
+        &mut self,
+        address: Address,
+    ) -> Result<Account, DatabaseError> {
         match cache::get_account(&self.cache, &address) {
             Some(acc) => Ok(acc.clone()),
-            None => self.store.get_account(address),
+            None => self.get_account_from_database(address),
         }
     }
 

crates/vm/levm/src/utils.rs

@@ -331,7 +331,7 @@ pub fn eip7702_recover_address(
 /// The idea of this function comes from ethereum/execution-specs:
 /// https://github.com/ethereum/execution-specs/blob/951fc43a709b493f27418a8e57d2d6f3608cef84/src/ethereum/prague/vm/eoa_delegation.py#L115
 pub fn eip7702_get_code(
-    db: &GeneralizedDatabase,
+    db: &mut GeneralizedDatabase,
     accrued_substate: &mut Substate,
     address: Address,
 ) -> Result<(bool, u64, Address, Bytes), VMError> {