Transaction: Change transactions to go through unified EVM runner

Simplify transaction validations to use `runComputation`; drop other code.

Getting everything right up to this point to pass all the tests was trickier
than it looks.

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

nimbus/transaction/call_evm.nim

@@ -113,60 +113,21 @@ proc rpcEstimateGas*(call: RpcCallData, header: BlockHeader, chain: BaseChainDB,
   let callResult = rpcRunComputation(vmState, call, gasLimit, some(fork), true)
   return callResult.gasUsed
 
-proc txSetupComputation(tx: Transaction, sender: EthAddress, vmState: BaseVMState, fork: Fork): Computation =
-  var gas = tx.gasLimit - tx.intrinsicGas(fork)
-  assert gas >= 0
-  return setupComputation(CallParams(
+proc txCallEvm*(tx: Transaction, sender: EthAddress, vmState: BaseVMState, fork: Fork): GasInt =
+  var call = CallParams(
     vmState:      vmState,
     forkOverride: some(fork),
     gasPrice:     tx.gasPrice,
-    gasLimit:     gas,
+    gasLimit:     tx.gasLimit,
     sender:       sender,
     to:           tx.to,
     isCreate:     tx.isContractCreation,
     value:        tx.value,
     input:        tx.payload
-  ))
-
-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(sender))
-      for c in activePrecompiles():
-        db.accessList(c)
-
-      # EIP2930 optional access list
-      if tx.txType == AccessListTxType:
-        for n in tx.accessListTx.accessList:
-          db.accessList(n.address)
-          for x in n.storageKeys:
-            db.accessList(n.address, UInt256.fromBytesBE(x))
-
-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
+  )
+  if tx.txType == AccessListTxType:
+    shallowCopy(call.accessList, tx.accessListTx.accessList)
+  return runComputation(call).gasUsed
 
 type
   AsmResult* = object