EVMC refundGas not breaching host/evm separation anymore (#2395)

nimbus/evm/computation.nim

@@ -372,9 +372,6 @@ template chainTo*(c: Computation,
     c.continuation = nil
     after
 
-func merge*(c, child: Computation) =
-  c.gasMeter.refundGas(child.gasMeter.gasRefunded)
-
 proc execSelfDestruct*(c: Computation, beneficiary: EthAddress) =
   c.vmState.mutateStateDB:
     let localBalance = c.getBalance(c.msg.contractAddress)

nimbus/evm/interpreter/op_handlers/oph_call.nim

@@ -162,7 +162,8 @@ when evmc_enabled:
         ? c.memory.write(p.memOutPos,
           c.returnData.toOpenArray(0, actualOutputSize - 1))
 
-      c.gasMeter.returnGas(GasInt c.res.gas_left)
+      c.gasMeter.returnGas(c.res.gas_left)
+      c.gasMeter.refundGas(c.res.gas_refund)
 
       if c.res.status_code == EVMC_SUCCESS:
         ? c.stack.top(1)
@@ -185,7 +186,7 @@ else:
         c.gasMeter.returnGas(child.gasMeter.gasRemaining)
 
       if child.isSuccess:
-        c.merge(child)
+        c.gasMeter.refundGas(child.gasMeter.gasRefunded)
         ? c.stack.top(1)
 
       c.returnData = child.output

nimbus/evm/interpreter/op_handlers/oph_create.nim

@@ -45,7 +45,8 @@ when not defined(evmc_enabled):
 when evmc_enabled:
   template execSubCreate(c: Computation; msg: ref nimbus_message) =
     c.chainTo(msg):
-      c.gasMeter.returnGas(GasInt c.res.gas_left)
+      c.gasMeter.returnGas(c.res.gas_left)
+      c.gasMeter.refundGas(c.res.gas_refund)
       if c.res.status_code == EVMC_SUCCESS:
         ? c.stack.top(c.res.create_address)
       elif c.res.status_code == EVMC_REVERT:
@@ -69,7 +70,7 @@ else:
         c.gasMeter.returnGas(child.gasMeter.gasRemaining)
 
       if child.isSuccess:
-        c.merge(child)
+        c.gasMeter.refundGas(child.gasMeter.gasRefunded)
         ? c.stack.top child.msg.contractAddress
       elif not child.error.burnsGas: # Means return was `REVERT`.
         # From create, only use `outputData` if child returned with `REVERT`.

nimbus/transaction/evmc_vm_glue.nim

@@ -62,8 +62,8 @@ proc evmcExecute(vm: ptr evmc_vm, hostInterface: ptr evmc_host_interface,
     status_code: c.evmcStatus,
     # Gas left is required to be zero when not `EVMC_SUCCESS` or `EVMC_REVERT`.
     gas_left:    if result.status_code notin {EVMC_SUCCESS, EVMC_REVERT}: 0'i64
-                 else: c.gasMeter.gasRemaining.int64,
-    gas_refund:  if result.status_code == EVMC_SUCCESS: c.gasMeter.gasRefunded.int64
+                 else: c.gasMeter.gasRemaining,
+    gas_refund:  if result.status_code == EVMC_SUCCESS: c.gasMeter.gasRefunded
                  else: 0'i64,
     output_data: output_data,
     output_size: output_size.csize_t,

nimbus/transaction/host_call_nested.nim

@@ -42,7 +42,7 @@ proc afterExecCreateEvmcNested(host: TransactionHost, child: Computation,
     res.gas_left = child.gasMeter.gasRemaining
 
   if child.isSuccess:
-    host.computation.merge(child)
+    res.gas_refund = child.gasMeter.gasRefunded
     res.status_code = EVMC_SUCCESS
     res.create_address = child.msg.contractAddress.toEvmc
   else:
@@ -78,7 +78,7 @@ proc afterExecCallEvmcNested(host: TransactionHost, child: Computation,
     res.gas_left = child.gasMeter.gasRemaining
 
   if child.isSuccess:
-    host.computation.merge(child)
+    res.gas_refund = child.gasMeter.gasRefunded
     res.status_code = EVMC_SUCCESS
   else:
     res.status_code = child.evmcStatus