public override void Execute()
{
// Obtain the values for our call value, and call data memory.
BigInteger value = Stack.Pop();
BigInteger inputMemoryStart = Stack.Pop();
BigInteger inputMemorySize = Stack.Pop();
// We'll want to charge for memory expansion first
Memory.ExpandStream(inputMemoryStart, inputMemorySize);
// If we're in a static context, we can't self destruct
if (Message.IsStatic)
{
throw new EVMException($"{Opcode.ToString()} instruction cannot execute in a static context!");
}
// Verify we have enough balance and call depth hasn't exceeded the maximum.
if (EVM.State.GetBalance(Message.To) >= value && Message.Depth < EVMDefinitions.MAX_CALL_DEPTH)
{
// Obtain our call information.
byte[] callData = Memory.ReadBytes((long)inputMemoryStart, (int)inputMemorySize);
BigInteger innerCallGas = GasState.Gas;
if (Version >= EthereumRelease.TangerineWhistle)
{
innerCallGas = GasDefinitions.GetMaxCallGas(innerCallGas);
}
// Create our message
EVMMessage message = new EVMMessage(Message.To, Address.ZERO_ADDRESS, value, innerCallGas, callData, Message.Depth + 1, Address.ZERO_ADDRESS, true, Message.IsStatic);
EVMExecutionResult innerVMResult = MeadowEVM.CreateContract(EVM.State, message);
if (innerVMResult.Succeeded)
{
// Push our resulting address onto the stack.
Stack.Push(BigIntegerConverter.GetBigInteger(innerVMResult.ReturnData.ToArray()));
EVM.ExecutionState.LastCallResult = null;
}
else
{
// We failed, push our fail value and put the last call data in place.
Stack.Push(0);
ExecutionState.LastCallResult = innerVMResult;
}
}
else
{
// We didn't have a sufficient balance or call depth so we push nothing to the stack. We push 0 (fail)
Stack.Push(0);
// Set our last call result as null.
ExecutionState.LastCallResult = null;
}
}
public override void Execute()
{
// Obtain all of our values for the call (the value variable is only used in some calls, and is zero otherwise)
BigInteger gas = Stack.Pop(); // The base amount of gas we allocate to the call.
Address to = Stack.Pop(); // The address we're making the call to.
BigInteger value = 0;
if (Opcode == InstructionOpcode.CALL || Opcode == InstructionOpcode.CALLCODE)
{
value = Stack.Pop();
}
// Obtain the values for where our input memory comes from, and where our output memory will go to.
BigInteger inputMemoryStart = Stack.Pop();
BigInteger inputMemorySize = Stack.Pop();
BigInteger outputMemoryStart = Stack.Pop();
BigInteger outputMemorySize = Stack.Pop();
// CALL opcode can only make static calls with a zero value.
if (Opcode == InstructionOpcode.CALL && Message.IsStatic && value != 0)
{
throw new EVMException($"Cannot use opcode {Opcode.ToString()} in a static context call with any value but zero.");
}
// Gas: Pre-Expand Memory (since it should be charged for expansion, then the call should be made, then written to)
Memory.ExpandStream(inputMemoryStart, inputMemorySize);
Memory.ExpandStream(outputMemoryStart, outputMemorySize);
// Gas: Calculate extra gas costs based off of forks and what kind of call this is.
BigInteger extraGasCost = 0;
// Gas: If this is a call and the account doesn't exist
if (Opcode == InstructionOpcode.CALL && !EVM.State.ContainsAccount(to))
{
// If the value is above zero (or if we're pre-spurious dragon) we charge for calling a new account.
if (value > 0 || Version < EthereumRelease.SpuriousDragon)
{
extraGasCost = GasDefinitions.GAS_CALL_NEW_ACCOUNT;
}
}
// If we are transferring a value, we charge gas
if (value > 0)
{
extraGasCost += GasDefinitions.GAS_CALL_VALUE;
}
// Tangerine whistle introduces new inner call gas limits
// Source: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-150.md
if (Version < EthereumRelease.TangerineWhistle)
{
// Prior to tangerine whistle, we need the provided gas + extra gas available
GasState.Check(gas + extraGasCost);
}
else
{
// After tangerine whistle, we check that the desired gas amount for the call doesn't exceed our calculated max call gas (or else it's capped).
GasState.Check(extraGasCost);
gas = BigInteger.Min(gas, GasDefinitions.GetMaxCallGas(GasState.Gas - extraGasCost));
}
// Define how much gas our inner message can take.
BigInteger innerCallGas = gas;
if (value > 0)
{
innerCallGas += GasDefinitions.GAS_CALL_VALUE_STIPEND;
}
// Verify we have enough balance and call depth hasn't exceeded the maximum.
if (EVM.State.GetBalance(Message.To) >= value && Message.Depth < EVMDefinitions.MAX_CALL_DEPTH)
{
// We're going to make an inner call, so we charge our gas and extra gas.
GasState.Deduct(gas + extraGasCost);
// Obtain our call data.
byte[] callData = Memory.ReadBytes((long)inputMemoryStart, (int)inputMemorySize);
// Create our message
EVMMessage innerMessage = null;
switch (Opcode)
{
case InstructionOpcode.CALL:
innerMessage = new EVMMessage(Message.To, to, value, innerCallGas, callData, Message.Depth + 1, to, true, Message.IsStatic);
break;
case InstructionOpcode.DELEGATECALL:
innerMessage = new EVMMessage(Message.Sender, Message.To, Message.Value, innerCallGas, callData, Message.Depth + 1, to, false, Message.IsStatic);
break;
case InstructionOpcode.STATICCALL:
innerMessage = new EVMMessage(Message.To, to, value, innerCallGas, callData, Message.Depth + 1, to, true, true);
break;
case InstructionOpcode.CALLCODE:
innerMessage = new EVMMessage(Message.To, Message.To, value, innerCallGas, callData, Message.Depth + 1, to, true, Message.IsStatic);
break;
}
// Execute our message in an inner VM.
EVMExecutionResult innerVMResult = MeadowEVM.Execute(EVM.State, innerMessage);
// Refund our remaining gas that the inner VM didn't use.
GasState.Refund(innerVMResult.RemainingGas);
// Set our last call results
ExecutionState.LastCallResult = innerVMResult;
// Push a status indicating whether execution had succeeded without reverting changes.
if (!innerVMResult.Succeeded)
{
Stack.Push(0);
}
else
{
Stack.Push(1);
}
// Determine how much we want to copy out.
int returnCopyLength = Math.Min(ExecutionState.LastCallResult?.ReturnData.Length ?? 0, (int)outputMemorySize);
if (returnCopyLength == 0 || ExecutionState.LastCallResult?.ReturnData == null)
{
return;
}
// Copy our data out
Memory.Write((long)outputMemoryStart, ExecutionState.LastCallResult.ReturnData.ToArray());
}
else
{
// We didn't have a sufficient balance or call depth so we push nothing to the stack. We push 0 (fail)
Stack.Push(0);
// Set our last call result as null.
ExecutionState.LastCallResult = null;
// Since we couldn't make an inner message call, we charge all the other extra charges, but not the inner message call cost. (Note: inner call gas comes from gas, so we put it here to offset potential extra cost from stipend)
GasState.Deduct(gas + extraGasCost - innerCallGas);
}
}
