public ILStack Clone()
{
ILStack clone = new ILStack();
foreach(Slot s in this.Items) {
clone.Items.Add(new Slot(s.PushedBy, s.Type));
}
return clone;
}
public void StackAnalysis(List<Instruction> body, MethodDefinition methodDef)
{
Queue<Instruction> agenda = new Queue<Instruction>();
// Add known states
stackBefore[body[0]] = new ILStack();
agenda.Enqueue(body[0]);
if(methodDef.Body.HasExceptionHandlers) {
foreach(ExceptionHandler ex in methodDef.Body.ExceptionHandlers) {
stackBefore[ex.TryStart] = new ILStack();
agenda.Enqueue(ex.TryStart);
ILStack stack = new ILStack();
stack.Items.Add(new ILStack.Slot(null, MyRocks.TypeException));
stackBefore[ex.HandlerStart] = stack;
agenda.Enqueue(ex.HandlerStart);
}
}
// Process agenda
while(agenda.Count > 0) {
Instruction inst = agenda.Dequeue();
// What is the effect of the instruction on the stack?
ILStack newStack = stackBefore[inst].Clone();
int popCount = inst.GetPopCount();
if (popCount == int.MaxValue) popCount = stackBefore[inst].Items.Count; // Pop all
List<TypeReference> typeArgs = new List<TypeReference>();
for (int i = newStack.Items.Count - popCount; i < newStack.Items.Count; i++) {
typeArgs.Add(newStack.Items[i].Type);
}
TypeReference type;
try {
type = inst.GetTypeInternal(methodDef, typeArgs);
} catch {
type = MyRocks.TypeObject;
}
if (popCount > 0) {
newStack.Items.RemoveRange(newStack.Items.Count - popCount, popCount);
}
int pushCount = inst.GetPushCount();
for (int i = 0; i < pushCount; i++) {
newStack.Items.Add(new ILStack.Slot(inst, type));
}
// Apply the state to any successors
List<Instruction> branchTargets = new List<Instruction>();
if (inst.OpCode.CanFallThough()) {
branchTargets.Add(inst.Next);
}
if (inst.OpCode.IsBranch()) {
if (inst.Operand is Instruction[]) {
branchTargets.AddRange((Instruction[])inst.Operand);
} else {
branchTargets.Add((Instruction)inst.Operand);
}
}
foreach (Instruction branchTarget in branchTargets) {
ILStack nextStack;
if (stackBefore.TryGetValue(branchTarget, out nextStack)) {
// TODO: Compare stacks
} else {
stackBefore[branchTarget] = newStack;
agenda.Enqueue(branchTarget);
}
}
}
}
