internal static bool IsCatchWhenBlock(Block block)
{
var container = BlockContainer.FindClosestContainer(block);
return(container?.Parent is TryCatchHandler handler &&
handler.Filter == container);
}
void IILTransform.Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.AnonymousMethods)
{
return;
}
this.context = context;
this.decompilationContext = new SimpleTypeResolveContext(function.Method);
var orphanedVariableInits = new List <ILInstruction>();
var targetsToReplace = new List <IInstructionWithVariableOperand>();
var translatedDisplayClasses = new HashSet <ITypeDefinition>();
var cancellationToken = context.CancellationToken;
foreach (var inst in function.Descendants)
{
cancellationToken.ThrowIfCancellationRequested();
if (inst is NewObj call)
{
context.StepStartGroup($"TransformDelegateConstruction {call.StartILOffset}", call);
ILFunction f = TransformDelegateConstruction(call, out ILInstruction target);
if (f != null && target is IInstructionWithVariableOperand instWithVar)
{
if (instWithVar.Variable.Kind == VariableKind.Local)
{
instWithVar.Variable.Kind = VariableKind.DisplayClassLocal;
}
targetsToReplace.Add(instWithVar);
}
context.StepEndGroup();
}
if (inst.MatchStLoc(out ILVariable targetVariable, out ILInstruction value))
{
var newObj = value as NewObj;
// TODO : it is probably not a good idea to remove *all* display-classes
// is there a way to minimize the false-positives?
if (newObj != null && IsInSimpleDisplayClass(newObj.Method))
{
targetVariable.CaptureScope = BlockContainer.FindClosestContainer(inst);
targetsToReplace.Add((IInstructionWithVariableOperand)inst);
translatedDisplayClasses.Add(newObj.Method.DeclaringTypeDefinition);
}
}
}
foreach (var target in targetsToReplace.OrderByDescending(t => ((ILInstruction)t).StartILOffset))
{
context.Step($"TransformDisplayClassUsages {target.Variable}", (ILInstruction)target);
function.AcceptVisitor(new TransformDisplayClassUsages(function, target, target.Variable.CaptureScope, orphanedVariableInits, translatedDisplayClasses));
}
context.Step($"Remove orphanedVariableInits", function);
foreach (var store in orphanedVariableInits)
{
if (store.Parent is Block containingBlock)
{
containingBlock.Instructions.Remove(store);
}
}
}
private void DetermineCaptureAndDeclarationScopes(Dictionary <MethodDefinitionHandle, LocalFunctionInfo> .ValueCollection localFunctions)
{
foreach (var info in localFunctions)
{
context.CancellationToken.ThrowIfCancellationRequested();
if (info.Definition == null)
{
context.Function.Warnings.Add($"Could not decode local function '{info.Method}'");
continue;
}
context.StepStartGroup($"Determine and move to declaration scope of " + info.Definition.Name, info.Definition);
try
{
var localFunction = info.Definition;
foreach (var useSite in info.UseSites)
{
DetermineCaptureAndDeclarationScope(info, useSite);
if (context.Function.Method.IsConstructor && localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = BlockContainer.FindClosestContainer(useSite);
}
}
if (localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = (BlockContainer)context.Function.Body;
}
ILFunction declaringFunction = GetDeclaringFunction(localFunction);
if (declaringFunction != context.Function)
{
context.Step($"Move {localFunction.Name} from {context.Function.Name} to {declaringFunction.Name}", localFunction);
context.Function.LocalFunctions.Remove(localFunction);
declaringFunction.LocalFunctions.Add(localFunction);
}
if (TryValidateSkipCount(info, out int skipCount) && skipCount != localFunction.ReducedMethod.NumberOfCompilerGeneratedTypeParameters)
{
Debug.Assert(false);
context.Function.Warnings.Add($"Could not decode local function '{info.Method}'");
if (declaringFunction != context.Function)
{
declaringFunction.LocalFunctions.Remove(localFunction);
}
}
}
finally
{
context.StepEndGroup(keepIfEmpty: true);
}
}
}
void IILTransform.Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.AnonymousMethods)
{
return;
}
var prevContext = this.context;
var prevDecompilationContext = this.decompilationContext;
try
{
activeMethods.Push((MethodDefinitionHandle)function.Method.MetadataToken);
this.context = context;
this.decompilationContext = new SimpleTypeResolveContext(function.Method);
var cancellationToken = context.CancellationToken;
foreach (var inst in function.Descendants)
{
cancellationToken.ThrowIfCancellationRequested();
if (!MatchDelegateConstruction(inst, out var targetMethod, out var target,
out var delegateType, allowTransformed: false))
{
continue;
}
context.StepStartGroup($"TransformDelegateConstruction {inst.StartILOffset}", inst);
ILFunction f = TransformDelegateConstruction(inst, targetMethod, target, delegateType);
if (f != null && target is IInstructionWithVariableOperand instWithVar)
{
var v = instWithVar.Variable;
if (v.Kind == VariableKind.Local)
{
v.Kind = VariableKind.DisplayClassLocal;
}
if (v.IsSingleDefinition &&
v.StoreInstructions.SingleOrDefault() is StLoc store &&
store.Value is NewObj)
{
v.CaptureScope = BlockContainer.FindClosestContainer(store);
}
}
context.StepEndGroup();
}
}
finally
{
this.context = prevContext;
this.decompilationContext = prevDecompilationContext;
activeMethods.Pop();
}
}
bool ShouldSwapIfTargets(ILInstruction inst1, ILInstruction inst2)
{
Block block1 = null, block2 = null;
if (inst1.MatchBranch(out block1) && inst2.MatchBranch(out block2))
{
// prefer arranging stuff in IL order
return(block1.ILRange.Start > block2.ILRange.Start);
}
BlockContainer container1, container2;
if (inst1.MatchLeave(out container1) && container1.Parent is TryInstruction)
{
// 'leave tryBlock' is considered to have a later target than
// any branch within the container, and also a later target
// than a return instruction.
// This is necessary to avoid "goto" statements in the
// ExceptionHandling.ConditionalReturnInThrow test.
if (!inst2.MatchLeave(out container2))
{
container2 = block2?.Parent as BlockContainer;
}
return(container2 == null || container2.IsDescendantOf(container1));
}
if (inst1.MatchBranch(out block1) && inst2.MatchLeave(out container2) &&
block1.IncomingEdgeCount > 1)
{
// if (..) goto x; leave c;
// Unless x can be inlined, it's better to swap the order if the 'leave'
// has a chance to turn into a 'break;' or 'return;'
if (container2.Parent is ILFunction)
{
return(true); // return
}
if (container2.EntryPoint.IncomingEdgeCount > 1)
{
// break
return(BlockContainer.FindClosestContainer(inst2) == container2);
}
}
return(false);
}
void IILTransform.Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.AnonymousMethods)
{
return;
}
this.context = context;
this.decompilationContext = new SimpleTypeResolveContext(function.Method);
var cancellationToken = context.CancellationToken;
foreach (var inst in function.Descendants)
{
cancellationToken.ThrowIfCancellationRequested();
if (inst is NewObj call)
{
context.StepStartGroup($"TransformDelegateConstruction {call.StartILOffset}", call);
ILFunction f = TransformDelegateConstruction(call, out ILInstruction target);
if (f != null && target is IInstructionWithVariableOperand instWithVar)
{
if (instWithVar.Variable.Kind == VariableKind.Local)
{
instWithVar.Variable.Kind = VariableKind.DisplayClassLocal;
}
var displayClassTypeDef = instWithVar.Variable.Type.GetDefinition();
if (instWithVar.Variable.IsSingleDefinition && instWithVar.Variable.StoreInstructions.SingleOrDefault() is StLoc store)
{
if (store.Value is NewObj newObj)
{
instWithVar.Variable.CaptureScope = BlockContainer.FindClosestContainer(store);
}
}
}
context.StepEndGroup();
}
}
}
/// <summary>
/// The transform works like this:
///
/// <para>
/// local functions can either be used in method calls, i.e., call and callvirt instructions,
/// or can be used as part of the "delegate construction" pattern, i.e.,
/// <c>newobj Delegate(<target-expression>, ldftn <method>)</c>.
/// </para>
/// As local functions can be declared practically anywhere, we have to take a look at
/// all use-sites and infer the declaration location from that. Use-sites can be call,
/// callvirt and ldftn instructions.
/// After all use-sites are collected we construct the ILAst of the local function
/// and add it to the parent function.
/// Then all use-sites of the local-function are transformed to a call to the
/// <c>LocalFunctionMethod</c> or a ldftn of the <c>LocalFunctionMethod</c>.
/// In a next step we handle all nested local functions.
/// After all local functions are transformed, we move all local functions that capture
/// any variables to their respective declaration scope.
/// </summary>
public void Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.LocalFunctions)
{
return;
}
// Disable the transform if we are decompiling a display-class or local function method:
// This happens if a local function or display class is selected in the ILSpy tree view.
if (IsLocalFunctionMethod(function.Method, context) || IsLocalFunctionDisplayClass(function.Method.ParentModule.PEFile, (TypeDefinitionHandle)function.Method.DeclaringTypeDefinition.MetadataToken, context))
{
return;
}
this.context = context;
this.resolveContext = new SimpleTypeResolveContext(function.Method);
var localFunctions = new Dictionary <MethodDefinitionHandle, LocalFunctionInfo>();
var cancellationToken = context.CancellationToken;
// Find all local functions declared inside this method, including nested local functions or local functions declared in lambdas.
FindUseSites(function, context, localFunctions);
foreach (var(_, info) in localFunctions)
{
cancellationToken.ThrowIfCancellationRequested();
if (info.Definition == null)
{
function.Warnings.Add($"Could not decode local function '{info.Method}'");
continue;
}
context.StepStartGroup($"Transform " + info.Definition.Name, info.Definition);
try {
var localFunction = info.Definition;
if (!localFunction.Method.IsStatic)
{
var thisVar = localFunction.Variables.SingleOrDefault(VariableKindExtensions.IsThis);
var target = info.UseSites.Where(us => us.Arguments[0].MatchLdLoc(out _)).FirstOrDefault()?.Arguments[0];
if (target == null)
{
target = info.UseSites[0].Arguments[0];
if (target.MatchLdFld(out var target1, out var field) && thisVar.Type.Equals(field.Type) && field.Type.Kind == TypeKind.Class && TransformDisplayClassUsage.IsPotentialClosure(context, field.Type.GetDefinition()))
{
var variable = function.Descendants.OfType <ILFunction>().SelectMany(f => f.Variables).Where(v => !v.IsThis() && TransformDisplayClassUsage.IsClosure(context, v, out var varType, out _) && varType.Equals(field.Type)).OnlyOrDefault();
if (variable != null)
{
target = new LdLoc(variable);
HandleArgument(localFunction, 1, 0, target);
}
}
}
context.Step($"Replace 'this' with {target}", localFunction);
localFunction.AcceptVisitor(new DelegateConstruction.ReplaceDelegateTargetVisitor(target, thisVar));
}
foreach (var useSite in info.UseSites)
{
DetermineCaptureAndDeclarationScope(localFunction, useSite);
if (function.Method.IsConstructor && localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = BlockContainer.FindClosestContainer(useSite);
}
}
if (localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = (BlockContainer)function.Body;
}
ILFunction declaringFunction = GetDeclaringFunction(localFunction);
if (declaringFunction != function)
{
function.LocalFunctions.Remove(localFunction);
declaringFunction.LocalFunctions.Add(localFunction);
}
if (TryValidateSkipCount(info, out int skipCount) && skipCount != localFunction.ReducedMethod.NumberOfCompilerGeneratedTypeParameters)
{
Debug.Assert(false);
function.Warnings.Add($"Could not decode local function '{info.Method}'");
if (declaringFunction != function)
{
declaringFunction.LocalFunctions.Remove(localFunction);
}
continue;
}
foreach (var useSite in info.UseSites)
{
context.Step($"Transform use site at IL_{useSite.StartILOffset:x4}", useSite);
if (useSite.OpCode == OpCode.NewObj)
{
TransformToLocalFunctionReference(localFunction, useSite);
}
else
{
TransformToLocalFunctionInvocation(localFunction.ReducedMethod, useSite);
}
}
} finally {
context.StepEndGroup();
}
}
}
/// <summary>
/// The transform works like this:
///
/// <para>
/// local functions can either be used in method calls, i.e., call and callvirt instructions,
/// or can be used as part of the "delegate construction" pattern, i.e., <c>newobj Delegate(<target-expression>, ldftn <method>)</c>.
/// </para>
/// As local functions can be declared practically anywhere, we have to take a look at all use-sites and infer the declaration location from that. Use-sites can be call, callvirt and ldftn instructions.
/// After all use-sites are collected we construct the ILAst of the local function and add it to the parent function.
/// Then all use-sites of the local-function are transformed to a call to the <c>LocalFunctionMethod</c> or a ldftn of the <c>LocalFunctionMethod</c>.
/// In a next step we handle all nested local functions.
/// After all local functions are transformed, we move all local functions that capture any variables to their respective declaration scope.
/// </summary>
public void Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.LocalFunctions)
{
return;
}
this.context = context;
this.resolveContext = new SimpleTypeResolveContext(function.Method);
var localFunctions = new Dictionary <MethodDefinitionHandle, LocalFunctionInfo>();
var cancellationToken = context.CancellationToken;
// Find all local functions declared inside this method, including nested local functions or local functions declared in lambdas.
FindUseSites(function, context, localFunctions);
foreach (var(method, info) in localFunctions)
{
cancellationToken.ThrowIfCancellationRequested();
var firstUseSite = info.UseSites[0];
context.StepStartGroup($"Transform " + info.Definition.Name, info.Definition);
try {
var localFunction = info.Definition;
if (!localFunction.Method.IsStatic)
{
var target = firstUseSite.Arguments[0];
context.Step($"Replace 'this' with {target}", localFunction);
var thisVar = localFunction.Variables.SingleOrDefault(VariableKindExtensions.IsThis);
localFunction.AcceptVisitor(new DelegateConstruction.ReplaceDelegateTargetVisitor(target, thisVar));
}
foreach (var useSite in info.UseSites)
{
context.Step($"Transform use site at IL_{useSite.StartILOffset:x4}", useSite);
if (useSite.OpCode == OpCode.NewObj)
{
TransformToLocalFunctionReference(localFunction, useSite);
}
else
{
DetermineCaptureAndDeclarationScope(localFunction, useSite);
TransformToLocalFunctionInvocation(localFunction.ReducedMethod, useSite);
}
if (function.Method.IsConstructor && localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = BlockContainer.FindClosestContainer(useSite);
}
}
if (localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = (BlockContainer)function.Body;
}
else if (localFunction.DeclarationScope != function.Body && localFunction.DeclarationScope.Parent is ILFunction declaringFunction)
{
function.LocalFunctions.Remove(localFunction);
declaringFunction.LocalFunctions.Add(localFunction);
}
} finally {
context.StepEndGroup();
}
}
}
private BlockContainer FindBlockContainer(Block block)
{
return(BlockContainer.FindClosestContainer(block) ?? throw new NotSupportedException());
}
public static void Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.AwaitInCatchFinally)
{
return;
}
HashSet <BlockContainer> changedContainers = new HashSet <BlockContainer>();
// analyze all try-catch statements in the function
foreach (var tryCatch in function.Descendants.OfType <TryCatch>().ToArray())
{
if (!(tryCatch.Parent?.Parent is BlockContainer container))
{
continue;
}
// await in finally uses a single catch block with catch-type object
if (tryCatch.Handlers.Count != 1 || !(tryCatch.Handlers[0].Body is BlockContainer catchBlockContainer) || !tryCatch.Handlers[0].Variable.Type.IsKnownType(KnownTypeCode.Object))
{
continue;
}
// and consists of an assignment to a temporary that is used outside the catch block
// and a jump to the finally block
var block = catchBlockContainer.EntryPoint;
if (block.Instructions.Count < 2 || !block.Instructions[0].MatchStLoc(out var globalCopyVar, out var value) || !value.MatchLdLoc(tryCatch.Handlers[0].Variable))
{
continue;
}
if (block.Instructions.Count == 3)
{
if (!block.Instructions[1].MatchStLoc(out var globalCopyVarTemp, out value) || !value.MatchLdLoc(globalCopyVar))
{
continue;
}
globalCopyVar = globalCopyVarTemp;
}
if (!block.Instructions[block.Instructions.Count - 1].MatchBranch(out var entryPointOfFinally))
{
continue;
}
// globalCopyVar should only be used once, at the end of the finally-block
if (globalCopyVar.LoadCount != 1 || globalCopyVar.StoreCount > 2)
{
continue;
}
var tempStore = globalCopyVar.LoadInstructions[0].Parent as StLoc;
if (tempStore == null || !MatchExceptionCaptureBlock(tempStore, out var exitOfFinally, out var afterFinally, out var blocksToRemove))
{
continue;
}
if (!MatchAfterFinallyBlock(ref afterFinally, blocksToRemove, out bool removeFirstInstructionInAfterFinally))
{
continue;
}
var cfg = new ControlFlowGraph(container, context.CancellationToken);
var exitOfFinallyNode = cfg.GetNode(exitOfFinally);
var entryPointOfFinallyNode = cfg.GetNode(entryPointOfFinally);
var additionalBlocksInFinally = new HashSet <Block>();
var invalidExits = new List <ControlFlowNode>();
TraverseDominatorTree(entryPointOfFinallyNode);
void TraverseDominatorTree(ControlFlowNode node)
{
if (entryPointOfFinallyNode != node)
{
if (entryPointOfFinallyNode.Dominates(node))
{
additionalBlocksInFinally.Add((Block)node.UserData);
}
else
{
invalidExits.Add(node);
}
}
if (node == exitOfFinallyNode)
{
return;
}
foreach (var child in node.DominatorTreeChildren)
{
TraverseDominatorTree(child);
}
}
if (invalidExits.Any())
{
continue;
}
context.Step("Inline finally block with await", tryCatch.Handlers[0]);
foreach (var blockToRemove in blocksToRemove)
{
blockToRemove.Remove();
}
var finallyContainer = new BlockContainer();
entryPointOfFinally.Remove();
if (removeFirstInstructionInAfterFinally)
{
afterFinally.Instructions.RemoveAt(0);
}
changedContainers.Add(container);
var outer = BlockContainer.FindClosestContainer(container.Parent);
if (outer != null)
{
changedContainers.Add(outer);
}
finallyContainer.Blocks.Add(entryPointOfFinally);
finallyContainer.AddILRange(entryPointOfFinally);
exitOfFinally.Instructions.RemoveRange(tempStore.ChildIndex, 3);
exitOfFinally.Instructions.Add(new Leave(finallyContainer));
foreach (var branchToFinally in container.Descendants.OfType <Branch>())
{
if (branchToFinally.TargetBlock == entryPointOfFinally)
{
branchToFinally.ReplaceWith(new Branch(afterFinally));
}
}
foreach (var newBlock in additionalBlocksInFinally)
{
newBlock.Remove();
finallyContainer.Blocks.Add(newBlock);
finallyContainer.AddILRange(newBlock);
}
tryCatch.ReplaceWith(new TryFinally(tryCatch.TryBlock, finallyContainer).WithILRange(tryCatch.TryBlock));
}
// clean up all modified containers
foreach (var container in changedContainers)
{
container.SortBlocks(deleteUnreachableBlocks: true);
}
}
