private void Spill(List <AssemblyOperation> operations, Instruction instruction, Address address)
{
foreach (Register register in _registers.All)
{
LiveAnalysisEntry candidateEntry = instruction.LiveVariableEntries.FirstOrDefault(x => x.Variable.Register != null && !instruction.GetAddresses().Contains(x.Variable));
if (candidateEntry != null)
{
string registerName = candidateEntry.Variable.Register.Name;
candidateEntry.Variable.Register.Clear();
operations.Add(new MoveOperation()
{
Target = candidateEntry.Variable.ToMemoryLocation(),
Value = registerName
});
operations.Add(new XorInstruction()
{
Target = registerName,
Value = registerName
});
candidateEntry.Variable.Spilled = true;
TryAssignRegister(address);
return;
}
}
}
private void AllocateRegister(ref int relativeAddress, Instruction instruction, Address address, List <AssemblyOperation> operations)
{
if (address == null)
{
return;
}
address.CalculateRelativeAddress(ref relativeAddress);
if (address is ConstantValue)
{
return;
}
if (!TryAssignRegister(address))
{
LiveAnalysisEntry deadEntry = instruction.LiveVariableEntries.FirstOrDefault(x => x.NextUse == null && x.Variable.Register != null);
if (deadEntry != null)
{
deadEntry.Variable.Register.Clear();
TryAssignRegister(address);
if (address.Spilled)
{
operations.Add(new MoveOperation()
{
Target = address.Register.Name,
Value = address.ToMemoryLocation()
});
}
else
{
operations.Add(new XorInstruction()
{
Target = address.Register.Name,
Value = address.Register.Name
});
}
}
else
{
Spill(operations, instruction, address);
}
}
}
