public static CFGNode[] ConstructCFG(List <IInstruction> instructions)
{
CFGNode[] nodes = new CFGNode[instructions.Count];
int end = instructions.Count - 1;
for (int i = end; i >= 0; i--)
{
nodes[i] = new CFGNode(instructions[i], i == end ? null : nodes[i + 1]);
}
// Map Labels to instructions
Dictionary <LabelInstruction, CFGNode> labels = new Dictionary <LabelInstruction, CFGNode>();
List <LabelInstruction> activeLabels = new List <LabelInstruction>();
for (int i = 0; i < instructions.Count; i++)
{
if (instructions[i] is LabelInstruction label)
{
activeLabels.Add(label);
}
else if (activeLabels.Count > 0)
{
foreach (var activeLabel in activeLabels)
{
labels[activeLabel] = nodes[i];
}
activeLabels.Clear();
}
}
foreach (var node in nodes)
{
LabelInstruction?target = node.Instruction switch
{
ConditionalJump conditionalJump =>
conditionalJump.Target,
UnconditionalJump unconditionalJump =>
unconditionalJump.Target,
_ => null,
};
if (target != null && labels.TryGetValue(target.Value, out var successor))
{
node.Successors.Add(successor);
}
}
return(nodes);
}
private IEnumerable <NasmInstruction> CompileInstruction(int i, IInstruction instruction)
{
yield return(NasmInstruction.Comment(instruction.ToString()));
yield return(NasmInstruction.Comment("In = { " + string.Join(", ", RegisterAllocation.GetAllInAt(i)) + " }"));
foreach (var inst in instruction switch
{
UnaryComputationAssignment inst => CompileCore(inst),
BinaryComputationAssignment inst => CompileCore(inst),
ConditionalJump inst => CompileCore(inst),
UnconditionalJump inst => CompileCore(inst),
LabelInstruction inst => CompileCore(inst),
CallInstruction inst => CompileCore(i, inst),
ReturnInstruction inst => CompileCore(inst),
ParameterQueryAssignment inst => CompileCore(inst),
_ => throw new ArgumentException(nameof(instruction))
})
