fix CREATE opcode gas cost

nimbus/vm/computation.nim

@@ -175,8 +175,8 @@ proc writeContract*(computation: var BaseComputation, fork: Fork): bool =
   let storageAddr = computation.msg.storageAddress
   if computation.isSuicided(storageAddr): return
 
-  # tricky gasCost: 1,0,0 -> createCost. 0,0,x -> depositCost
-  let codeCost = computation.gasCosts[Create].m_handler(0, 0, contractCode.len)
+  let gasParams = GasParams(kind: Create, cr_memLength: contractCode.len)
+  let codeCost = computation.gasCosts[Create].c_handler(0.u256, gasParams).gasCost
   if computation.gasMeter.gasRemaining >= codeCost:
     computation.gasMeter.consumeGas(codeCost, reason = "Write contract code for CREATE")
     computation.vmState.mutateStateDb:

nimbus/vm/interpreter/gas_costs.nim

@@ -72,6 +72,10 @@ type
       c_memOffset*: Natural
       c_memLength*: Natural
       c_opCode*: Op
+    of Create:
+      cr_currentMemSize*: Natural
+      cr_memOffset*: Natural
+      cr_memLength*: Natural
     else:
       discard
 
@@ -169,10 +173,15 @@ template gasCosts(fork: Fork, prefix, ResultGasCostsName: untyped) =
     if not value.isZero:
       result += static(FeeSchedule[GasExpByte]) * (1 + log256(value))
 
-  func `prefix gasCreate`(currentMemSize, memOffset, memLength: Natural): GasInt {.nimcall.} =
-    # tricky gasCost: 1,0,0 -> createCost. 0,0,x -> depositCost
-    result = currentMemSize * static(FeeSchedule[GasCreate]) +
-      static(FeeSchedule[GasCodeDeposit]) * memLength
+  func `prefix gasCreate`(value: Uint256, gasParams: GasParams): GasResult {.nimcall.} =
+    if value.isZero:
+      result.gasCost = static(FeeSchedule[GasCodeDeposit]) * gasParams.cr_memLength
+    else:
+      result.gasCost = static(FeeSchedule[GasCreate]) +
+                       `prefix gasMemoryExpansion`(
+                          gasParams.cr_currentMemSize,
+                          gasParams.cr_memOffset,
+                          gasParams.cr_memLength)
 
   func `prefix gasSha3`(currentMemSize, memOffset, memLength: Natural): GasInt {.nimcall.} =
 
@@ -509,7 +518,7 @@ template gasCosts(fork: Fork, prefix, ResultGasCostsName: untyped) =
           Log4:           memExpansion `prefix gasLog4`,
 
           # f0s: System operations
-          Create:         memExpansion `prefix gasCreate`,  # TODO: Change to dynamic?
+          Create:         complex `prefix gasCreate`,
           Call:           complex `prefix gasCall`,
           CallCode:       complex `prefix gasCall`,
           Return:         memExpansion `prefix gasHalt`,

nimbus/vm/interpreter/opcodes_impl.nim

@@ -506,13 +506,17 @@ genLog()
 # ##########################################
 # f0s: System operations.
 
-proc canTransfer(computation: BaseComputation, memPos, len: int, value: Uint256): bool =
-  # tricky gasCost: 1,0,0 -> createCost. 0,0,x -> depositCost
-  let gasCost = computation.gasCosts[Create].m_handler(1, 0, 0)
-  let reason = &"CREATE: GasCreate + {len} * memory expansion"
+proc canTransfer(computation: BaseComputation, memPos, memLen: int, value: Uint256): bool =
+  let gasParams = GasParams(kind: Create,
+    cr_currentMemSize: computation.memory.len,
+    cr_memOffset: memPos,
+    cr_memLength: memLen
+    )
+  let gasCost = computation.gasCosts[Create].c_handler(1.u256, gasParams).gasCost
+  let reason = &"CREATE: GasCreate + {memLen} * memory expansion"
 
   computation.gasMeter.consumeGas(gasCost, reason = reason)
-  computation.memory.extend(memPos, len)
+  computation.memory.extend(memPos, memLen)
 
   # the sender is childmsg sender, not parent msg sender
   # perhaps we need to move this code somewhere else