/// <summary>
/// mcs likes to optimize closures in yield state machines away by moving the captured variables' fields into the state machine type,
/// We construct a <see cref="DisplayClass"/> that spans the whole method body.
/// </summary>
bool HandleMonoStateMachine(ILFunction currentFunction, ILVariable thisVariable, SimpleTypeResolveContext decompilationContext, ILFunction nestedFunction)
{
if (!(nestedFunction.StateMachineCompiledWithMono && thisVariable.IsThis()))
{
return(false);
}
// Special case for Mono-compiled yield state machines
ITypeDefinition closureType = thisVariable.Type.GetDefinition();
if (!(closureType != decompilationContext.CurrentTypeDefinition &&
IsPotentialClosure(decompilationContext.CurrentTypeDefinition, closureType, allowTypeImplementingInterfaces: true)))
{
return(false);
}
var displayClass = new DisplayClass {
IsMono = true,
Initializer = nestedFunction.Body,
Variable = thisVariable,
Definition = thisVariable.Type.GetDefinition(),
Variables = new Dictionary <IField, ILVariable>(),
CaptureScope = (BlockContainer)nestedFunction.Body
};
displayClasses.Add(thisVariable, displayClass);
foreach (var stateMachineVariable in nestedFunction.Variables)
{
if (stateMachineVariable.StateMachineField == null || displayClass.Variables.ContainsKey(stateMachineVariable.StateMachineField))
{
continue;
}
displayClass.Variables.Add(stateMachineVariable.StateMachineField, stateMachineVariable);
}
if (!currentFunction.Method.IsStatic && FindThisField(out var thisField))
{
var thisVar = currentFunction.Variables
.FirstOrDefault(t => t.IsThis() && t.Type.GetDefinition() == decompilationContext.CurrentTypeDefinition);
if (thisVar == null)
{
thisVar = new ILVariable(VariableKind.Parameter, decompilationContext.CurrentTypeDefinition, -1)
{
Name = "this"
};
currentFunction.Variables.Add(thisVar);
}
displayClass.Variables.Add(thisField, thisVar);
}
return(true);
bool FindThisField(out IField foundField)
{
foundField = null;
foreach (var field in closureType.GetFields(f2 => !f2.IsStatic && !displayClass.Variables.ContainsKey(f2) && f2.Type.GetDefinition() == decompilationContext.CurrentTypeDefinition))
{
thisField = field;
return(true);
}
return(false);
}
}
private DisplayClass AnalyzeVariable(ILVariable v)
{
switch (v.Kind)
{
case VariableKind.Parameter:
if (context.Settings.YieldReturn && v.Function.StateMachineCompiledWithMono && v.IsThis())
{
return(HandleMonoStateMachine(v.Function, v));
}
return(null);
case VariableKind.StackSlot:
case VariableKind.Local:
case VariableKind.DisplayClassLocal:
return(DetectDisplayClass(v));
case VariableKind.InitializerTarget:
return(DetectDisplayClassInitializer(v));
default:
return(null);
}
}
