Transaction: EIP-2930 (Berlin): Extra intrinsic gas for access list

Calculate extra intrinsic gas for an EIP-2930 transaction with access list.

While we're here, do the rest of the intrinsic gas calculation.  Make it clear,
explicit and in one place.  (Previous code delegated parts of the calculation
to `transaction.nim` but had to do the rest locally due to mismatched types.)

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

nimbus/transaction/call_common.nim

@@ -9,7 +9,7 @@
 import
   eth/common/eth_types, stint, options, stew/ranges/ptr_arith,
   ".."/[vm_types, vm_types2, vm_state, vm_computation, vm_state_transactions],
-  ".."/[db/accounts_cache, transaction, vm_precompiles, vm_gas_costs],
+  ".."/[db/accounts_cache, vm_precompiles, vm_gas_costs],
   ".."/vm_internals,
   ./host_types
 
@@ -55,6 +55,34 @@ proc hostToComputationMessage(msg: EvmcMessage): Message =
     flags:           if msg.isStatic: emvcStatic else: emvcNoFlags
   )
 
+# From EIP-2930 (Berlin).
+const
+  ACCESS_LIST_STORAGE_KEY_COST = 1900.GasInt
+  ACCESS_LIST_ADDRESS_COST     = 2400.GasInt
+
+func intrinsicGas(call: CallParams, fork: Fork): GasInt {.inline.} =
+  # Compute the baseline gas cost for this transaction.  This is the amount
+  # of gas needed to send this transaction (but that is not actually used
+  # for computation).
+  var gas = gasFees[fork][GasTransaction]
+
+  # EIP-2 (Homestead) extra intrinsic gas for contract creations.
+  if call.isCreate:
+    gas += gasFees[fork][GasTXCreate]
+
+  # Input data cost, reduced in EIP-2028 (Istanbul).
+  let gasZero    = gasFees[fork][GasTXDataZero]
+  let gasNonZero = gasFees[fork][GasTXDataNonZero]
+  for b in call.input:
+    gas += (if b == 0: gasZero else: gasNonZero)
+
+  # EIP-2930 (Berlin) intrinsic gas for transaction access list.
+  if fork >= FkBerlin:
+    for account in call.accessList:
+      gas += ACCESS_LIST_ADDRESS_COST
+      gas += account.storageKeys.len * ACCESS_LIST_STORAGE_KEY_COST
+  return gas
+
 proc initialAccessListEIP2929(call: CallParams) =
   # EIP2929 initial access list.
   let vmState = call.vmState
@@ -87,9 +115,7 @@ proc setupCall(call: CallParams, useIntrinsic: bool): TransactionHost =
 
   var intrinsicGas: GasInt = 0
   if useIntrinsic:
-    intrinsicGas = intrinsicGas(call.input, vmState.fork)
-    if call.isCreate:
-      intrinsicGas += gasFees[vmState.fork][GasTXCreate]
+    intrinsicGas = intrinsicGas(call, vmState.fork)
 
   let host = TransactionHost(
     vmState:       vmState,