ILFunction TransformDelegateConstruction(
ILInstruction value, IMethod targetMethod,
ILInstruction target, IType delegateType)
{
if (!IsAnonymousMethod(decompilationContext.CurrentTypeDefinition, targetMethod))
{
return(null);
}
if (targetMethod.MetadataToken.IsNil)
{
return(null);
}
if (LocalFunctionDecompiler.IsLocalFunctionMethod(targetMethod, context))
{
return(null);
}
if (!ValidateDelegateTarget(target))
{
return(null);
}
var handle = (MethodDefinitionHandle)targetMethod.MetadataToken;
if (activeMethods.Contains(handle))
{
this.context.Function.Warnings.Add(" Found self-referencing delegate construction. Abort transformation to avoid stack overflow.");
return(null);
}
var methodDefinition = context.PEFile.Metadata.GetMethodDefinition((MethodDefinitionHandle)targetMethod.MetadataToken);
if (!methodDefinition.HasBody())
{
return(null);
}
var genericContext = GenericContextFromTypeArguments(targetMethod.Substitution);
if (genericContext == null)
{
return(null);
}
var ilReader = context.CreateILReader();
var body = context.PEFile.Reader.GetMethodBody(methodDefinition.RelativeVirtualAddress);
var function = ilReader.ReadIL((MethodDefinitionHandle)targetMethod.MetadataToken, body, genericContext.Value, ILFunctionKind.Delegate, context.CancellationToken);
function.DelegateType = delegateType;
// Embed the lambda into the parent function's ILAst, so that "Show steps" can show
// how the lambda body is being transformed.
value.ReplaceWith(function);
function.CheckInvariant(ILPhase.Normal);
var contextPrefix = targetMethod.Name;
foreach (ILVariable v in function.Variables.Where(v => v.Kind != VariableKind.Parameter))
{
v.Name = contextPrefix + v.Name;
}
var nestedContext = new ILTransformContext(context, function);
function.RunTransforms(CSharpDecompiler.GetILTransforms().TakeWhile(t => !(t is DelegateConstruction)).Concat(GetTransforms()), nestedContext);
nestedContext.Step("DelegateConstruction (ReplaceDelegateTargetVisitor)", function);
function.AcceptVisitor(new ReplaceDelegateTargetVisitor(target, function.Variables.SingleOrDefault(VariableKindExtensions.IsThis)));
// handle nested lambdas
nestedContext.StepStartGroup("DelegateConstruction (nested lambdas)", function);
((IILTransform)this).Run(function, nestedContext);
nestedContext.StepEndGroup();
function.AddILRange(target);
function.AddILRange(value);
if (value is Call call)
{
function.AddILRange(call.Arguments[1]);
}
return(function);
}
ILFunction TransformDelegateConstruction(NewObj value, out ILInstruction target)
{
target = null;
if (!IsDelegateConstruction(value))
{
return(null);
}
var targetMethod = ((IInstructionWithMethodOperand)value.Arguments[1]).Method;
if (!IsAnonymousMethod(decompilationContext.CurrentTypeDefinition, targetMethod))
{
return(null);
}
if (LocalFunctionDecompiler.IsLocalFunctionMethod(targetMethod.ParentModule.PEFile, (MethodDefinitionHandle)targetMethod.MetadataToken))
{
return(null);
}
target = value.Arguments[0];
if (targetMethod.MetadataToken.IsNil)
{
return(null);
}
var methodDefinition = context.PEFile.Metadata.GetMethodDefinition((MethodDefinitionHandle)targetMethod.MetadataToken);
if (!methodDefinition.HasBody())
{
return(null);
}
var genericContext = GenericContextFromTypeArguments(targetMethod.Substitution);
if (genericContext == null)
{
return(null);
}
var ilReader = context.CreateILReader();
var body = context.PEFile.Reader.GetMethodBody(methodDefinition.RelativeVirtualAddress);
var function = ilReader.ReadIL((MethodDefinitionHandle)targetMethod.MetadataToken, body, genericContext.Value, context.CancellationToken);
function.DelegateType = value.Method.DeclaringType;
function.CheckInvariant(ILPhase.Normal);
// Embed the lambda into the parent function's ILAst, so that "Show steps" can show
// how the lambda body is being transformed.
value.ReplaceWith(function);
var contextPrefix = targetMethod.Name;
foreach (ILVariable v in function.Variables.Where(v => v.Kind != VariableKind.Parameter))
{
v.Name = contextPrefix + v.Name;
}
var nestedContext = new ILTransformContext(context, function);
function.RunTransforms(CSharpDecompiler.GetILTransforms().TakeWhile(t => !(t is DelegateConstruction)).Concat(GetTransforms()), nestedContext);
nestedContext.Step("DelegateConstruction (ReplaceDelegateTargetVisitor)", function);
function.AcceptVisitor(new ReplaceDelegateTargetVisitor(target, function.Variables.SingleOrDefault(v => v.Index == -1 && v.Kind == VariableKind.Parameter)));
// handle nested lambdas
nestedContext.StepStartGroup("DelegateConstruction (nested lambdas)", function);
((IILTransform) new DelegateConstruction()).Run(function, nestedContext);
nestedContext.StepEndGroup();
function.AddILRange(target);
function.AddILRange(value);
function.AddILRange(value.Arguments[1]);
return(function);
}
void PerformAssignment(ILFunction function)
{
// remove unused variables before assigning names
function.Variables.RemoveDead();
int numDisplayClassLocals = 0;
foreach (var v in function.Variables)
{
switch (v.Kind)
{
case VariableKind.Parameter: // ignore
break;
case VariableKind.InitializerTarget: // keep generated names
AddExistingName(reservedVariableNames, v.Name);
break;
case VariableKind.DisplayClassLocal:
v.Name = "CS$<>8__locals" + (numDisplayClassLocals++);
break;
default:
if (v.HasGeneratedName || !IsValidName(v.Name) || ConflictWithLocal(v))
{
// don't use the name from the debug symbols if it looks like a generated name
v.Name = null;
}
else
{
// use the name from the debug symbols
// (but ensure we don't use the same name for two variables)
v.Name = GetAlternativeName(v.Name);
}
break;
}
}
foreach (var localFunction in function.LocalFunctions)
{
if (!LocalFunctionDecompiler.ParseLocalFunctionName(localFunction.Name, out _, out var newName) || !IsValidName(newName))
{
newName = null;
}
localFunction.Name = newName;
}
// Now generate names:
var mapping = new Dictionary <ILVariable, string>(ILVariableEqualityComparer.Instance);
foreach (var inst in function.Descendants.OfType <IInstructionWithVariableOperand>())
{
var v = inst.Variable;
if (!mapping.TryGetValue(v, out string name))
{
if (string.IsNullOrEmpty(v.Name))
{
v.Name = GenerateNameForVariable(v);
}
mapping.Add(v, v.Name);
}
else
{
v.Name = name;
}
}
foreach (var localFunction in function.LocalFunctions)
{
var newName = localFunction.Name;
if (newName == null)
{
newName = GetAlternativeName("f");
}
localFunction.Name = newName;
}
}
public void Run(ILFunction function, ILTransformContext context)
{
try {
if (this.context != null)
{
throw new InvalidOperationException("Reentrancy in " + nameof(TransformDisplayClassUsage));
}
this.context = context;
var decompilationContext = new SimpleTypeResolveContext(context.Function.Method);
// Traverse nested functions in post-order:
// Inner functions are transformed before outer functions
foreach (var f in function.Descendants.OfType <ILFunction>())
{
foreach (var v in f.Variables.ToArray())
{
if (HandleMonoStateMachine(function, v, decompilationContext, f))
{
continue;
}
if (IsClosure(v, out ITypeDefinition closureType, out var inst))
{
AddOrUpdateDisplayClass(f, v, closureType, inst, localFunctionClosureParameter: false);
}
if (context.Settings.LocalFunctions && f.Kind == ILFunctionKind.LocalFunction && v.Kind == VariableKind.Parameter && v.Index > -1 && f.Method.Parameters[v.Index.Value] is IParameter p && LocalFunctionDecompiler.IsClosureParameter(p, decompilationContext))
{
AddOrUpdateDisplayClass(f, v, ((ByReferenceType)p.Type).ElementType.GetDefinition(), f.Body, localFunctionClosureParameter: true);
}
}
}
VisitILFunction(function);
if (instructionsToRemove.Count > 0)
{
context.Step($"Remove instructions", function);
foreach (var store in instructionsToRemove)
{
if (store.Parent is Block containingBlock)
{
containingBlock.Instructions.Remove(store);
}
}
}
RemoveDeadVariableInit.ResetHasInitialValueFlag(function, context);
} finally {
instructionsToRemove.Clear();
displayClasses.Clear();
this.context = null;
}
}
void PerformAssignment(ILFunction function)
{
// remove unused variables before assigning names
function.Variables.RemoveDead();
int numDisplayClassLocals = 0;
Dictionary <int, string> assignedLocalSignatureIndices = new Dictionary <int, string>();
foreach (var v in function.Variables.OrderBy(v => v.Name))
{
switch (v.Kind)
{
case VariableKind.Parameter: // ignore
break;
case VariableKind.InitializerTarget: // keep generated names
AddExistingName(reservedVariableNames, v.Name);
break;
case VariableKind.DisplayClassLocal:
v.Name = "CS$<>8__locals" + (numDisplayClassLocals++);
break;
case VariableKind.Local when v.Index != null:
if (assignedLocalSignatureIndices.TryGetValue(v.Index.Value, out string name))
{
// make sure all local ILVariables that refer to the same slot in the locals signature
// are assigned the same name.
v.Name = name;
}
else
{
AssignName();
// Remember the newly assigned name:
assignedLocalSignatureIndices.Add(v.Index.Value, v.Name);
}
break;
default:
AssignName();
break;
}
void AssignName()
{
if (v.HasGeneratedName || !IsValidName(v.Name) || ConflictWithLocal(v))
{
// don't use the name from the debug symbols if it looks like a generated name
v.Name = null;
}
else
{
// use the name from the debug symbols
// (but ensure we don't use the same name for two variables)
v.Name = GetAlternativeName(v.Name);
}
}
}
foreach (var localFunction in function.LocalFunctions)
{
if (!LocalFunctionDecompiler.ParseLocalFunctionName(localFunction.Name, out _, out var newName) || !IsValidName(newName))
{
newName = null;
}
localFunction.Name = newName;
localFunction.ReducedMethod.Name = newName;
}
// Now generate names:
var mapping = new Dictionary <ILVariable, string>(ILVariableEqualityComparer.Instance);
foreach (var inst in function.Descendants.OfType <IInstructionWithVariableOperand>())
{
var v = inst.Variable;
if (!mapping.TryGetValue(v, out string name))
{
if (string.IsNullOrEmpty(v.Name))
{
v.Name = GenerateNameForVariable(v);
}
mapping.Add(v, v.Name);
}
else
{
v.Name = name;
}
}
foreach (var localFunction in function.LocalFunctions)
{
var newName = localFunction.Name;
if (newName == null)
{
newName = GetAlternativeName("f");
}
localFunction.Name = newName;
localFunction.ReducedMethod.Name = newName;
localFunctionMapping[(MethodDefinitionHandle)localFunction.ReducedMethod.MetadataToken] = newName;
}
foreach (var inst in function.Descendants)
{
LocalFunctionMethod localFunction;
switch (inst)
{
case Call call:
localFunction = call.Method as LocalFunctionMethod;
break;
case LdFtn ldftn:
localFunction = ldftn.Method as LocalFunctionMethod;
break;
default:
localFunction = null;
break;
}
if (localFunction == null || !localFunctionMapping.TryGetValue((MethodDefinitionHandle)localFunction.MetadataToken, out var name))
{
continue;
}
localFunction.Name = name;
}
}
