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 (context.Settings.YieldReturn && HandleMonoStateMachine(function, v, decompilationContext, f))
{
continue;
}
if ((context.Settings.AnonymousMethods || context.Settings.ExpressionTrees) && IsClosure(context, v, out ITypeDefinition closureType, out var inst))
{
if (!CanRemoveAllReferencesTo(context, v))
{
continue;
}
if (inst is StObj || inst is StLoc)
{
instructionsToRemove.Add(inst);
}
AddOrUpdateDisplayClass(f, v, closureType, inst, localFunctionClosureParameter: false);
continue;
}
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);
continue;
}
AnalyzeUseSites(v);
}
}
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);
}
}
}
foreach (var f in TreeTraversal.PostOrder(function, f => f.LocalFunctions))
{
RemoveDeadVariableInit.ResetHasInitialValueFlag(f, context);
}
} finally {
instructionsToRemove.Clear();
displayClasses.Clear();
fieldAssignmentsWithVariableValue.Clear();
this.context = null;
}
}
/// <summary>
/// Inlines the stloc instruction at block.Instructions[pos] into the next instruction, if possible.
/// </summary>
public static bool InlineOneIfPossible(Block block, int pos, InliningOptions options, ILTransformContext context)
{
context.CancellationToken.ThrowIfCancellationRequested();
StLoc stloc = block.Instructions[pos] as StLoc;
if (stloc == null || stloc.Variable.Kind == VariableKind.PinnedLocal)
{
return(false);
}
ILVariable v = stloc.Variable;
// ensure the variable is accessed only a single time
if (v.StoreCount != 1)
{
return(false);
}
if (v.LoadCount > 1 || v.LoadCount + v.AddressCount != 1)
{
return(false);
}
// TODO: inlining of small integer types might be semantically incorrect,
// but we can't avoid it this easily without breaking lots of tests.
//if (v.Type.IsSmallIntegerType())
// return false; // stloc might perform implicit truncation
return(InlineOne(stloc, options, context));
}
public static bool InlineAllInBlock(ILFunction function, Block block, ILTransformContext context)
{
int?ctorCallStart = null;
return(InlineAllInBlock(function, block, context, ref ctorCallStart));
}
void IILTransform.Run(ILFunction function, ILTransformContext context)
{
var callsToFix = new List <Call>();
foreach (var call in function.Descendants.OfType <Call>())
{
if (!(call.Method.IsOperator && (call.Method.Name == "op_Increment" || call.Method.Name == "op_Decrement")))
{
continue;
}
if (call.Arguments.Count != 1)
{
continue;
}
if (call.Method.DeclaringType.IsKnownType(KnownTypeCode.Decimal))
{
// For decimal, legacy csc can optimize "d + 1m" to "op_Increment(d)".
// We can handle these calls in ReplaceMethodCallsWithOperators.
continue;
}
callsToFix.Add(call);
}
foreach (var call in callsToFix)
{
// A user-defined increment/decrement that was not handled by TransformAssignment.
// This can happen because the variable-being-incremented was optimized out by Roslyn,
// e.g.
// public void Issue1552Pre(UserType a, UserType b)
// {
// UserType num = a + b;
// Console.WriteLine(++num);
// }
// can end up being compiled to:
// Console.WriteLine(UserType.op_Increment(a + b));
if (call.SlotInfo == StLoc.ValueSlot && call.Parent.SlotInfo == Block.InstructionSlot)
{
var store = (StLoc)call.Parent;
var block = (Block)store.Parent;
context.Step($"Fix {call.Method.Name} call at 0x{call.StartILOffset:x4} using {store.Variable.Name}", call);
// stloc V(call op_Increment(...))
// ->
// stloc V(...)
// compound.assign op_Increment(V)
call.ReplaceWith(call.Arguments[0]);
block.Instructions.Insert(store.ChildIndex + 1,
new UserDefinedCompoundAssign(call.Method, CompoundEvalMode.EvaluatesToNewValue,
new LdLoca(store.Variable), CompoundTargetKind.Address, new LdcI4(1)).WithILRange(call));
}
else
{
context.Step($"Fix {call.Method.Name} call at 0x{call.StartILOffset:x4} using new local", call);
var newVariable = call.Arguments[0].Extract(context);
if (newVariable == null)
{
Debug.Fail("Failed to extract argument of remaining increment/decrement");
continue;
}
newVariable.Type = call.GetParameter(0).Type;
Debug.Assert(call.Arguments[0].MatchLdLoc(newVariable));
call.ReplaceWith(new UserDefinedCompoundAssign(call.Method, CompoundEvalMode.EvaluatesToNewValue,
new LdLoca(newVariable), CompoundTargetKind.Address, new LdcI4(1)).WithILRange(call));
}
}
}
internal static bool IsPotentialClosure(ILTransformContext context, ITypeDefinition potentialDisplayClass)
{
var decompilationContext = new SimpleTypeResolveContext(context.Function.Ancestors.OfType <ILFunction>().Last().Method);
return(IsPotentialClosure(decompilationContext.CurrentTypeDefinition, potentialDisplayClass));
}
private bool PatternMatchRefTypes(Block block, BlockContainer container, ILTransformContext context, ref ControlFlowGraph?cfg)
{
if (!block.MatchIfAtEndOfBlock(out var condition, out var trueInst, out var falseInst))
{
return(false);
}
int pos = block.Instructions.Count - 3;
if (condition.MatchLdLoc(out var conditionVar))
{
// stloc conditionVar(comp.o(ldloc s == ldnull))
// if (logic.not(ldloc conditionVar)) br trueBlock
if (pos < 0)
{
return(false);
}
if (!(conditionVar.IsSingleDefinition && conditionVar.LoadCount == 1 &&
conditionVar.Kind == VariableKind.StackSlot))
{
return(false);
}
if (!block.Instructions[pos].MatchStLoc(conditionVar, out condition))
{
return(false);
}
pos--;
}
if (condition.MatchCompEqualsNull(out var loadInNullCheck))
{
ExtensionMethods.Swap(ref trueInst, ref falseInst);
}
else if (condition.MatchCompNotEqualsNull(out loadInNullCheck))
{
// do nothing
}
else
{
return(false);
}
if (!loadInNullCheck.MatchLdLoc(out var s))
{
return(false);
}
if (!s.IsSingleDefinition)
{
return(false);
}
if (s.Kind is not(VariableKind.Local or VariableKind.StackSlot))
{
return(false);
}
if (pos < 0)
{
return(false);
}
// stloc V(isinst T(testedOperand))
ILInstruction storeToV = block.Instructions[pos];
if (!storeToV.MatchStLoc(out var v, out var value))
{
return(false);
}
if (value.MatchLdLoc(s))
{
// stloc v(ldloc s)
pos--;
if (pos < 0 || !block.Instructions[pos].MatchStLoc(s, out value))
{
return(false);
}
if (v.Kind is not(VariableKind.Local or VariableKind.StackSlot))
{
return(false);
}
if (s.LoadCount != 2)
{
return(false);
}
}
else
{
if (v != s)
{
return(false);
}
}
IType?unboxType;
if (value is UnboxAny unboxAny)
{
// stloc S(unbox.any T(isinst T(testedOperand)))
unboxType = unboxAny.Type;
value = unboxAny.Argument;
}
else
{
unboxType = null;
}
if (value is not IsInst {
Argument : var testedOperand, Type : var type
})
/// <summary>
/// Inlines 'expr' into 'next', if possible.
///
/// Note that this method does not check whether 'v' has only one use;
/// the caller is expected to validate whether inlining 'v' has any effects on other uses of 'v'.
/// </summary>
static bool DoInline(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, InliningOptions options, ILTransformContext context)
{
var r = FindLoadInNext(next, v, inlinedExpression, options);
if (r.Type == FindResultType.Found || r.Type == FindResultType.NamedArgument)
{
var loadInst = r.LoadInst;
if (loadInst.OpCode == OpCode.LdLoca)
{
if (!IsGeneratedValueTypeTemporary((LdLoca)loadInst, v, inlinedExpression))
{
return(false);
}
}
else
{
Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
bool aggressive = (options & InliningOptions.Aggressive) != 0;
if (!aggressive && v.Kind != VariableKind.StackSlot &&
!NonAggressiveInlineInto(next, r, inlinedExpression, v))
{
return(false);
}
}
if (r.Type == FindResultType.NamedArgument)
{
NamedArgumentTransform.IntroduceNamedArgument(r.CallArgument, context);
// Now that the argument is evaluated early, we can inline as usual
}
context.Step($"Inline variable '{v.Name}'", inlinedExpression);
// Assign the ranges of the ldloc instruction:
inlinedExpression.AddILRange(loadInst);
if (loadInst.OpCode == OpCode.LdLoca)
{
// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
// to preserve the semantics of the compiler-generated temporary
Debug.Assert(((LdLoca)loadInst).Variable == v);
loadInst.ReplaceWith(new AddressOf(inlinedExpression, v.Type));
}
else
{
loadInst.ReplaceWith(inlinedExpression);
}
return(true);
}
return(false);
}
public void Run(ILFunction function, ILTransformContext context)
{
this.context = context;
Default(function);
}
public void Run(ILFunction function, ILTransformContext context)
{
this.context = context;
foreach (var inst in function.Descendants.OfType <CallInstruction>())
{
MethodDefinition methodDef = context.TypeSystem.GetCecil(inst.Method) as MethodDefinition;
if (methodDef != null && methodDef.Body != null)
{
if (inst.Method.IsCompilerGeneratedOrIsInCompilerGeneratedClass())
{
// partially copied from CSharpDecompiler
var specializingTypeSystem = this.context.TypeSystem.GetSpecializingTypeSystem(inst.Method.Substitution);
var ilReader = new ILReader(specializingTypeSystem);
System.Threading.CancellationToken cancellationToken = new System.Threading.CancellationToken();
var proxyFunction = ilReader.ReadIL(methodDef.Body, cancellationToken);
var transformContext = new ILTransformContext(proxyFunction, specializingTypeSystem, this.context.Settings)
{
CancellationToken = cancellationToken,
DecompileRun = context.DecompileRun
};
foreach (var transform in CSharp.CSharpDecompiler.GetILTransforms())
{
if (transform.GetType() != typeof(ProxyCallReplacer)) // don't call itself on itself
{
cancellationToken.ThrowIfCancellationRequested();
transform.Run(proxyFunction, transformContext);
}
}
if (!(proxyFunction.Body is BlockContainer blockContainer))
{
return;
}
if (blockContainer.Blocks.Count != 1)
{
return;
}
var block = blockContainer.Blocks[0];
Call call = null;
if (block.Instructions.Count == 1)
{
// leave IL_0000 (call Test(ldloc this, ldloc A_1))
if (!block.Instructions[0].MatchLeave(blockContainer, out ILInstruction returnValue))
{
return;
}
call = returnValue as Call;
}
else if (block.Instructions.Count == 2)
{
// call Test(ldloc this, ldloc A_1)
// leave IL_0000(nop)
call = block.Instructions[0] as Call;
if (!block.Instructions[1].MatchLeave(blockContainer, out ILInstruction returnValue))
{
return;
}
if (!returnValue.MatchNop())
{
return;
}
}
if (call == null)
{
return;
}
if (call.Method.IsConstructor)
{
return;
}
// check if original arguments are only correct ldloc calls
for (int i = 0; i < call.Arguments.Count; i++)
{
var originalArg = call.Arguments[i];
if (!originalArg.MatchLdLoc(out ILVariable var) ||
var.Kind != VariableKind.Parameter ||
var.Index != i - 1)
{
return;
}
}
Call newInst = (Call)call.Clone();
newInst.Arguments.ReplaceList(inst.Arguments);
inst.ReplaceWith(newInst);
}
}
}
}
internal static bool IsPotentialClosure(ILTransformContext context, NewObj inst)
{
var decompilationContext = new SimpleTypeResolveContext(context.TypeSystem.Resolve(context.Function.Method));
return(IsPotentialClosure(decompilationContext.CurrentTypeDefinition, inst.Method.DeclaringTypeDefinition));
}
public BlockTransformContext(ILTransformContext context) : base(context)
{
}
/// <summary>
/// Inlines 'expr' into 'next', if possible.
///
/// Note that this method does not check whether 'v' has only one use;
/// the caller is expected to validate whether inlining 'v' has any effects on other uses of 'v'.
/// </summary>
static bool DoInline(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, bool aggressive, ILTransformContext context)
{
ILInstruction loadInst;
if (FindLoadInNext(next, v, inlinedExpression, out loadInst) == true)
{
if (loadInst.OpCode == OpCode.LdLoca)
{
if (!IsGeneratedValueTypeTemporary(next, loadInst.Parent, loadInst.ChildIndex, v, inlinedExpression))
{
return(false);
}
}
else
{
Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
if (!aggressive && v.Kind != VariableKind.StackSlot && !NonAggressiveInlineInto(next, loadInst, inlinedExpression, v))
{
return(false);
}
}
context.Step($"Inline variable '{v.Name}'", inlinedExpression);
// Assign the ranges of the ldloc instruction:
inlinedExpression.AddILRange(loadInst.ILRange);
if (loadInst.OpCode == OpCode.LdLoca)
{
// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
// to preserve the semantics of the compiler-generated temporary
loadInst.ReplaceWith(new AddressOf(inlinedExpression));
}
else
{
loadInst.ReplaceWith(inlinedExpression);
}
return(true);
}
return(false);
}
/// <summary>
/// Inlines the stloc instruction at block.Instructions[pos] into the next instruction, if possible.
/// </summary>
public static bool InlineOneIfPossible(Block block, int pos, bool aggressive, ILTransformContext context)
{
context.CancellationToken.ThrowIfCancellationRequested();
StLoc stloc = block.Instructions[pos] as StLoc;
if (stloc == null || stloc.Variable.Kind == VariableKind.PinnedLocal)
{
return(false);
}
ILVariable v = stloc.Variable;
// ensure the variable is accessed only a single time
if (v.StoreCount != 1)
{
return(false);
}
if (v.LoadCount > 1 || v.LoadCount + v.AddressCount != 1)
{
return(false);
}
return(InlineOne(stloc, aggressive, context));
}
void Run(CallInstruction inst, ILTransformContext context)
{
if (inst.Method.IsStatic)
{
return;
}
if (inst.Method.MetadataToken.IsNil || inst.Method.MetadataToken.Kind != HandleKind.MethodDefinition)
{
return;
}
var handle = (MethodDefinitionHandle)inst.Method.MetadataToken;
if (!IsDefinedInCurrentOrOuterClass(inst.Method, context.Function.Method.DeclaringTypeDefinition))
{
return;
}
if (!inst.Method.IsCompilerGeneratedOrIsInCompilerGeneratedClass())
{
return;
}
var metadata = context.PEFile.Metadata;
MethodDefinition methodDef = metadata.GetMethodDefinition((MethodDefinitionHandle)inst.Method.MetadataToken);
if (!methodDef.HasBody())
{
return;
}
var genericContext = DelegateConstruction.GenericContextFromTypeArguments(inst.Method.Substitution);
if (genericContext == null)
{
return;
}
// partially copied from CSharpDecompiler
var ilReader = context.CreateILReader();
var body = context.PEFile.Reader.GetMethodBody(methodDef.RelativeVirtualAddress);
var proxyFunction = ilReader.ReadIL(handle, body, genericContext.Value, context.CancellationToken);
var transformContext = new ILTransformContext(context, proxyFunction);
proxyFunction.RunTransforms(CSharp.CSharpDecompiler.EarlyILTransforms(), transformContext);
if (!(proxyFunction.Body is BlockContainer blockContainer))
{
return;
}
if (blockContainer.Blocks.Count != 1)
{
return;
}
var block = blockContainer.Blocks[0];
Call call;
ILInstruction returnValue;
switch (block.Instructions.Count)
{
case 1:
// leave IL_0000 (call Test(ldloc this, ldloc A_1))
if (!block.Instructions[0].MatchLeave(blockContainer, out returnValue))
{
return;
}
call = returnValue as Call;
break;
case 2:
// call Test(ldloc this, ldloc A_1)
// leave IL_0000(nop)
call = block.Instructions[0] as Call;
if (!block.Instructions[1].MatchLeave(blockContainer, out returnValue))
{
return;
}
if (!returnValue.MatchNop())
{
return;
}
break;
default:
return;
}
if (call == null || call.Method.IsConstructor)
{
return;
}
if (call.Method.IsStatic || call.Method.Parameters.Count != inst.Method.Parameters.Count)
{
return;
}
// check if original arguments are only correct ldloc calls
for (int i = 0; i < call.Arguments.Count; i++)
{
var originalArg = call.Arguments[i];
if (!originalArg.MatchLdLoc(out ILVariable var) ||
var.Kind != VariableKind.Parameter ||
var.Index != i - 1)
{
return;
}
}
context.Step("Replace proxy: " + inst.Method.Name + " with " + call.Method.Name, inst);
Call newInst = (Call)call.Clone();
newInst.Arguments.ReplaceList(inst.Arguments);
inst.ReplaceWith(newInst);
}
public NullPropagationTransform(ILTransformContext context)
{
this.context = context;
}
static void DoPropagate(ILVariable v, ILInstruction copiedExpr, Block block, ref int i, ILTransformContext context)
{
context.Step($"Copy propagate {v.Name}", copiedExpr);
// un-inline the arguments of the ldArg instruction
ILVariable[] uninlinedArgs = new ILVariable[copiedExpr.Children.Count];
for (int j = 0; j < uninlinedArgs.Length; j++)
{
var arg = copiedExpr.Children[j];
var type = context.TypeSystem.FindType(arg.ResultType);
uninlinedArgs[j] = new ILVariable(VariableKind.StackSlot, type, arg.ResultType)
{
Name = "C_" + arg.StartILOffset,
HasGeneratedName = true,
};
block.Instructions.Insert(i++, new StLoc(uninlinedArgs[j], arg));
}
v.Function.Variables.AddRange(uninlinedArgs);
// perform copy propagation:
foreach (var expr in v.LoadInstructions.ToArray())
{
var clone = copiedExpr.Clone();
for (int j = 0; j < uninlinedArgs.Length; j++)
{
clone.Children[j].ReplaceWith(new LdLoc(uninlinedArgs[j]));
}
expr.ReplaceWith(clone);
}
block.Instructions.RemoveAt(i);
int c = ILInlining.InlineInto(block, i, InliningOptions.None, context: context);
i -= c + 1;
}
public void Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.Dynamic)
{
return;
}
this.context = context;
Dictionary <IField, CallSiteInfo> callsites = new Dictionary <IField, CallSiteInfo>();
HashSet <BlockContainer> modifiedContainers = new HashSet <BlockContainer>();
foreach (var block in function.Descendants.OfType <Block>())
{
if (block.Instructions.Count < 2)
{
continue;
}
// Check if, we deal with a callsite cache field null check:
// if (comp(ldsfld <>p__3 == ldnull)) br IL_000c
// br IL_002b
if (!(block.Instructions.SecondToLastOrDefault() is IfInstruction ifInst))
{
continue;
}
if (!(block.Instructions.LastOrDefault() is Branch branchAfterInit))
{
continue;
}
if (!MatchCallSiteCacheNullCheck(ifInst.Condition, out var callSiteCacheField, out var callSiteDelegate, out bool invertBranches))
{
continue;
}
if (!ifInst.TrueInst.MatchBranch(out var trueBlock))
{
continue;
}
Block callSiteInitBlock, targetBlockAfterInit;
if (invertBranches)
{
callSiteInitBlock = branchAfterInit.TargetBlock;
targetBlockAfterInit = trueBlock;
}
else
{
callSiteInitBlock = trueBlock;
targetBlockAfterInit = branchAfterInit.TargetBlock;
}
if (!ScanCallSiteInitBlock(callSiteInitBlock, callSiteCacheField, callSiteDelegate, out var callSiteInfo, out var blockAfterInit))
{
continue;
}
if (targetBlockAfterInit != blockAfterInit)
{
continue;
}
callSiteInfo.DelegateType = callSiteDelegate;
callSiteInfo.ConditionalJumpToInit = ifInst;
callSiteInfo.Inverted = invertBranches;
callSiteInfo.BranchAfterInit = branchAfterInit;
callsites.Add(callSiteCacheField, callSiteInfo);
}
var storesToRemove = new List <StLoc>();
foreach (var invokeCall in function.Descendants.OfType <CallVirt>())
{
if (invokeCall.Method.DeclaringType.Kind != TypeKind.Delegate || invokeCall.Method.Name != "Invoke" || invokeCall.Arguments.Count == 0)
{
continue;
}
var firstArgument = invokeCall.Arguments[0];
if (firstArgument.MatchLdLoc(out var stackSlot) && stackSlot.Kind == VariableKind.StackSlot && stackSlot.IsSingleDefinition)
{
firstArgument = ((StLoc)stackSlot.StoreInstructions[0]).Value;
}
if (!firstArgument.MatchLdFld(out var cacheFieldLoad, out var targetField))
{
continue;
}
if (!cacheFieldLoad.MatchLdsFld(out var cacheField))
{
continue;
}
if (!callsites.TryGetValue(cacheField, out var callsite))
{
continue;
}
context.Stepper.Step("Transform callsite for " + callsite.MemberName);
var deadArguments = new List <ILInstruction>();
ILInstruction replacement = MakeDynamicInstruction(callsite, invokeCall, deadArguments);
if (replacement == null)
{
continue;
}
invokeCall.ReplaceWith(replacement);
Debug.Assert(callsite.ConditionalJumpToInit?.Parent is Block);
var block = ((Block)callsite.ConditionalJumpToInit.Parent);
if (callsite.Inverted)
{
block.Instructions.Remove(callsite.ConditionalJumpToInit);
callsite.BranchAfterInit.ReplaceWith(callsite.ConditionalJumpToInit.TrueInst);
}
else
{
block.Instructions.Remove(callsite.ConditionalJumpToInit);
}
foreach (var arg in deadArguments)
{
if (arg.MatchLdLoc(out var temporary) && temporary.Kind == VariableKind.StackSlot && temporary.IsSingleDefinition && temporary.LoadCount == 0)
{
StLoc stLoc = (StLoc)temporary.StoreInstructions[0];
if (stLoc.Parent is Block storeParentBlock)
{
var value = stLoc.Value;
if (value.MatchLdsFld(out var cacheFieldCopy) && cacheFieldCopy.Equals(cacheField))
{
storesToRemove.Add(stLoc);
}
if (value.MatchLdFld(out cacheFieldLoad, out var targetFieldCopy) && cacheFieldLoad.MatchLdsFld(out cacheFieldCopy) && cacheField.Equals(cacheFieldCopy) && targetField.Equals(targetFieldCopy))
{
storesToRemove.Add(stLoc);
}
}
}
}
modifiedContainers.Add((BlockContainer)block.Parent);
}
foreach (var inst in storesToRemove)
{
Block parentBlock = (Block)inst.Parent;
parentBlock.Instructions.RemoveAt(inst.ChildIndex);
}
foreach (var container in modifiedContainers)
{
container.SortBlocks(deleteUnreachableBlocks: true);
}
}
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);
}
public void Run(ILFunction function, ILTransformContext context)
{
this.context = context;
currentFieldNames = function.Method.DeclaringTypeDefinition.Fields.Select(f => f.Name).ToArray();
reservedVariableNames = new Dictionary <string, int>();
loopCounters = CollectLoopCounters(function);
foreach (var f in function.Descendants.OfType <ILFunction>())
{
if (f.Method != null)
{
if (IsSetOrEventAccessor(f.Method) && f.Method.Parameters.Count > 0)
{
for (int i = 0; i < f.Method.Parameters.Count - 1; i++)
{
AddExistingName(reservedVariableNames, f.Method.Parameters[i].Name);
}
var lastParameter = f.Method.Parameters.Last();
switch (f.Method.AccessorOwner)
{
case IProperty prop:
if (f.Method.AccessorKind == MethodSemanticsAttributes.Setter)
{
if (prop.Parameters.Any(p => p.Name == "value"))
{
f.Warnings.Add("Parameter named \"value\" already present in property signature!");
break;
}
var variableForLastParameter = f.Variables.FirstOrDefault(v => v.Function == f &&
v.Kind == VariableKind.Parameter &&
v.Index == f.Method.Parameters.Count - 1);
if (variableForLastParameter == null)
{
AddExistingName(reservedVariableNames, lastParameter.Name);
}
else
{
if (variableForLastParameter.Name != "value")
{
variableForLastParameter.Name = "value";
}
AddExistingName(reservedVariableNames, variableForLastParameter.Name);
}
}
break;
case IEvent ev:
if (f.Method.AccessorKind != MethodSemanticsAttributes.Raiser)
{
var variableForLastParameter = f.Variables.FirstOrDefault(v => v.Function == f &&
v.Kind == VariableKind.Parameter &&
v.Index == f.Method.Parameters.Count - 1);
if (variableForLastParameter == null)
{
AddExistingName(reservedVariableNames, lastParameter.Name);
}
else
{
if (variableForLastParameter.Name != "value")
{
variableForLastParameter.Name = "value";
}
AddExistingName(reservedVariableNames, variableForLastParameter.Name);
}
}
break;
default:
AddExistingName(reservedVariableNames, lastParameter.Name);
break;
}
}
else
{
foreach (var p in f.Method.Parameters)
{
AddExistingName(reservedVariableNames, p.Name);
}
}
}
else
{
foreach (var p in f.Variables.Where(v => v.Kind == VariableKind.Parameter))
{
AddExistingName(reservedVariableNames, p.Name);
}
}
}
foreach (ILFunction f in function.Descendants.OfType <ILFunction>().Reverse())
{
PerformAssignment(f);
}
}
public void Run(Block block, BlockTransformContext context)
{
this.context = context;
Default(block);
}
public void Run(ILFunction function, ILTransformContext context)
{
throw new NotImplementedException();
}
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);
}
internal static bool IsPotentialClosure(ILTransformContext context, NewObj inst)
{
var decompilationContext = new SimpleTypeResolveContext(context.Function.Ancestors.OfType <ILFunction>().Last().Method);
return(IsPotentialClosure(decompilationContext.CurrentTypeDefinition, inst.Method.DeclaringTypeDefinition));
}
/// <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();
}
}
}
/// <summary>
/// Aggressively inlines the stloc instruction at block.Body[pos] into the next instruction, if possible.
/// </summary>
public static bool InlineIfPossible(Block block, int pos, ILTransformContext context)
{
return(InlineOneIfPossible(block, pos, InliningOptions.Aggressive, context));
}
public void Run(ILFunction function, ILTransformContext context)
{
ResetHasInitialValueFlag(function, context);
// Remove dead stores to variables that are never read from.
// If the stored value has some side-effect, the value is unwrapped.
// This is necessary to remove useless stores generated by some compilers, e.g., the F# compiler.
// In yield return + async, the C# compiler tends to store null/default(T) to variables
// when the variable goes out of scope.
if (function.IsAsync || function.IsIterator || context.Settings.RemoveDeadStores)
{
var variableQueue = new Queue <ILVariable>(function.Variables);
while (variableQueue.Count > 0)
{
var v = variableQueue.Dequeue();
if (v.Kind != VariableKind.Local && v.Kind != VariableKind.StackSlot)
{
continue;
}
// Skip variables that are captured in a mcs yield state-machine
// loads of these will only be visible after DelegateConstruction step.
if (function.StateMachineCompiledWithMono && v.StateMachineField != null)
{
continue;
}
if (v.LoadCount != 0 || v.AddressCount != 0)
{
continue;
}
foreach (var stloc in v.StoreInstructions.OfType <StLoc>().ToArray())
{
if (stloc.Parent is Block block)
{
if (SemanticHelper.IsPure(stloc.Value.Flags))
{
block.Instructions.Remove(stloc);
}
else
{
stloc.ReplaceWith(stloc.Value);
}
if (stloc.Value is LdLoc ldloc)
{
variableQueue.Enqueue(ldloc.Variable);
}
}
}
}
}
// Try to infer IType of stack slots that are of StackType.Ref:
foreach (var v in function.Variables)
{
if (v.Kind == VariableKind.StackSlot && v.StackType == StackType.Ref && v.AddressCount == 0)
{
IType newType = null;
// Multiple store are possible in case of (c ? ref a : ref b) += 1, for example.
foreach (var stloc in v.StoreInstructions.OfType <StLoc>())
{
var inferredType = stloc.Value.InferType(context.TypeSystem);
// cancel, if types of values do not match exactly
if (newType != null && !newType.Equals(inferredType))
{
newType = SpecialType.UnknownType;
break;
}
newType = inferredType;
}
// Only overwrite existing type, if a "better" type was found.
if (newType != null && newType != SpecialType.UnknownType)
{
v.Type = newType;
}
}
}
}
/// <summary>
/// Inlines 'expr' into 'next', if possible.
///
/// Note that this method does not check whether 'v' has only one use;
/// the caller is expected to validate whether inlining 'v' has any effects on other uses of 'v'.
/// </summary>
static bool DoInline(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, InliningOptions options, ILTransformContext context)
{
var r = FindLoadInNext(next, v, inlinedExpression, out var loadInst);
if (r == FindResult.Found)
{
if (loadInst.OpCode == OpCode.LdLoca)
{
if (!IsGeneratedValueTypeTemporary(next, (LdLoca)loadInst, v, inlinedExpression))
{
return(false);
}
}
else
{
Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
bool aggressive = (options & InliningOptions.Aggressive) != 0;
if (!aggressive && v.Kind != VariableKind.StackSlot &&
!NonAggressiveInlineInto(next, loadInst, inlinedExpression, v))
{
return(false);
}
}
context.Step($"Inline variable '{v.Name}'", inlinedExpression);
// Assign the ranges of the ldloc instruction:
inlinedExpression.AddILRange(loadInst.ILRange);
if (loadInst.OpCode == OpCode.LdLoca)
{
// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
// to preserve the semantics of the compiler-generated temporary
loadInst.ReplaceWith(new AddressOf(inlinedExpression));
}
else
{
loadInst.ReplaceWith(inlinedExpression);
}
return(true);
}
else if (r == FindResult.NamedArgument && (options & InliningOptions.IntroduceNamedArguments) != 0)
{
return(NamedArgumentTransform.DoInline(v, (StLoc)inlinedExpression.Parent, (LdLoc)loadInst,
options, context));
}
return(false);
}
void ClearState()
{
displayClasses.Clear();
this.decompilationContext = null;
this.context = null;
}
public NullableLiftingTransform(ILTransformContext context)
{
this.context = context;
this.nullableVars = null;
}
internal static bool IsClosure(ILTransformContext context, ILVariable variable, out ITypeDefinition closureType, out ILInstruction initializer)
{
return(IsClosure(context, variable, instructionsToRemove: null, out closureType, out initializer));
}
