Transaction: Make transaction validation use new function txCallEvm

Split out and move the EVM setup and call in `processTransaction` to
`call_evm`.  This is the last part of the main program which calls the EVM
to be moved.  (There's still test code.)

While we're here, move the EIP2929 access list setup too, as the similarity
to `rpcInitialAccessListEIP2929` is obvious.

Signed-off-by: Jamie Lokier <jamie@shareable.org>

nimbus/p2p/executor.nim

@@ -54,26 +54,8 @@ proc processTransaction*(tx: Transaction, sender: EthAddress, vmState: BaseVMSta
   trace "Sender", sender
   trace "txHash", rlpHash = tx.rlpHash
 
-  # EIP2929
-  if fork >= FkBerlin:
-    vmState.mutateStateDB:
-      db.accessList(sender)
-      if not tx.isContractCreation:
-        #If it's a create-tx, the destination will be added inside evm.create
-        db.accessList(tx.getRecipient)
-      for c in activePrecompiles():
-        db.accessList(c)
-
   if validateTransaction(vmState, tx, sender, fork):
-    var c = txSetupComputation(tx, sender, vmState, fork)
-    vmState.mutateStateDB:
-      db.subBalance(sender, tx.gasLimit.u256 * tx.gasPrice.u256)
-    execComputation(c)
-
-    result = tx.gasLimit
-    if not c.shouldBurnGas:
-      txRefundGas(tx, sender, c)
-      result -= c.gasMeter.gasRemaining
+    result = txCallEvm(tx, sender, vmState, fork)
 
   vmState.cumulativeGasUsed += result
 

nimbus/transaction/call_evm.nim

@@ -150,7 +150,7 @@ proc rpcEstimateGas*(call: RpcCallData, header: BlockHeader, chain: BaseChainDB,
   let refund = min(c.getGasRefund(), maxRefund)
   return gasLimit - c.gasMeter.gasRemaining - refund
 
-proc txSetupComputation*(tx: Transaction, sender: EthAddress, vmState: BaseVMState, fork: Fork): Computation =
+proc txSetupComputation(tx: Transaction, sender: EthAddress, vmState: BaseVMState, fork: Fork): Computation =
   var gas = tx.gasLimit - tx.intrinsicGas(fork)
   assert gas >= 0
 
@@ -174,9 +174,35 @@ proc txSetupComputation*(tx: Transaction, sender: EthAddress, vmState: BaseVMSta
   result = newComputation(vmState, msg)
   doAssert result.isOriginComputation
 
-proc txRefundGas*(tx: Transaction, sender: EthAddress, c: Computation) =
+proc txRefundgas(tx: Transaction, sender: EthAddress, c: Computation) =
   let maxRefund = (tx.gasLimit - c.gasMeter.gasRemaining) div 2
   let refund = min(c.getGasRefund(), maxRefund)
   c.gasMeter.returnGas(refund)
   c.vmState.mutateStateDB:
     db.addBalance(sender, c.gasMeter.gasRemaining.u256 * tx.gasPrice.u256)
+
+proc txInitialAccessListEIP2929(tx: Transaction, sender: EthAddress, vmState: BaseVMState, fork: Fork) =
+  # EIP2929 initial access list.
+  if fork >= FkBerlin:
+    vmState.mutateStateDB:
+      db.accessList(sender)
+      # For contract creations the EVM will add the contract address to the
+      # access list itself, after calculating the new contract address.
+      if not tx.isContractCreation:
+        db.accessList(tx.getRecipient())
+      for c in activePrecompiles():
+        db.accessList(c)
+
+proc txCallEvm*(tx: Transaction, sender: EthAddress, vmState: BaseVMState, fork: Fork): GasInt =
+  txInitialAccessListEIP2929(tx, sender, vmState, fork)
+
+  var c = txSetupComputation(tx, sender, vmState, fork)
+  vmState.mutateStateDB:
+    db.subBalance(sender, tx.gasLimit.u256 * tx.gasPrice.u256)
+
+  execComputation(c)
+
+  if c.shouldBurnGas:
+    return tx.gasLimit
+  txRefundGas(tx, sender, c)
+  return tx.gasLimit - c.gasMeter.gasRemaining