/// <summary>
/// if (comp(ldloc v == ldnull)) {
/// stloc v(DelegateConstruction)
/// }
/// =>
/// stloc v(DelegateConstruction)
/// </summary>
bool CachedDelegateInitializationWithLocal(IfInstruction inst)
{
Block trueInst = inst.TrueInst as Block;
if (trueInst == null || (trueInst.Instructions.Count != 1) || !inst.FalseInst.MatchNop())
{
return(false);
}
if (!inst.Condition.MatchCompEquals(out ILInstruction left, out ILInstruction right) || !left.MatchLdLoc(out ILVariable v) || !right.MatchLdNull())
{
return(false);
}
var storeInst = trueInst.Instructions.Last();
if (!storeInst.MatchStLoc(v, out ILInstruction value))
{
return(false);
}
if (!DelegateConstruction.IsDelegateConstruction(value as NewObj, true))
{
return(false);
}
// do not transform if there are other stores/loads of this variable
if (v.StoreCount != 2 || v.StoreInstructions.Count != 2 || v.LoadCount != 2 || v.AddressCount != 0)
{
return(false);
}
// do not transform if the first assignment is not assigning null:
var otherStore = v.StoreInstructions.OfType <StLoc>().SingleOrDefault(store => store != storeInst);
if (otherStore == null || !otherStore.Value.MatchLdNull() || !(otherStore.Parent is Block))
{
return(false);
}
// do not transform if there is no usage directly afterwards
var nextInstruction = inst.Parent.Children.ElementAtOrDefault(inst.ChildIndex + 1);
if (nextInstruction == null)
{
return(false);
}
var usages = nextInstruction.Descendants.Where(i => i.MatchLdLoc(v)).ToArray();
if (usages.Length != 1)
{
return(false);
}
context.Step("CachedDelegateInitializationWithLocal", inst);
((Block)otherStore.Parent).Instructions.Remove(otherStore);
inst.ReplaceWith(storeInst);
return(true);
}
/// <summary>
/// stloc s(ldobj(ldflda(CachedAnonMethodDelegate))
/// if (comp(ldloc s == null)) {
/// stloc s(stobj(ldflda(CachedAnonMethodDelegate), DelegateConstruction))
/// }
/// =>
/// stloc s(DelegateConstruction)
/// </summary>
bool CachedDelegateInitializationRoslynWithLocal(IfInstruction inst)
{
Block trueInst = inst.TrueInst as Block;
if (trueInst == null || (trueInst.Instructions.Count != 1) || !inst.FalseInst.MatchNop())
{
return(false);
}
if (!inst.Condition.MatchCompEquals(out ILInstruction left, out ILInstruction right) || !left.MatchLdLoc(out ILVariable s) || !right.MatchLdNull())
{
return(false);
}
var storeInst = trueInst.Instructions.Last() as StLoc;
var storeBeforeIf = inst.Parent.Children.ElementAtOrDefault(inst.ChildIndex - 1) as StLoc;
if (storeBeforeIf == null || storeInst == null || storeBeforeIf.Variable != s || storeInst.Variable != s)
{
return(false);
}
if (!(storeInst.Value is StObj stobj) || !(storeBeforeIf.Value is LdObj ldobj))
{
return(false);
}
if (!(stobj.Value is NewObj))
{
return(false);
}
if (!stobj.Target.MatchLdFlda(out var _, out var field1) || !ldobj.Target.MatchLdFlda(out var __, out var field2) || !field1.Equals(field2))
{
return(false);
}
if (!DelegateConstruction.IsDelegateConstruction((NewObj)stobj.Value, true))
{
return(false);
}
context.Step("CachedDelegateInitializationRoslynWithLocal", inst);
storeBeforeIf.Value = stobj.Value;
return(true);
}
/// <summary>
/// if (comp(ldsfld CachedAnonMethodDelegate == ldnull)) {
/// stsfld CachedAnonMethodDelegate(DelegateConstruction)
/// }
/// ... one usage of CachedAnonMethodDelegate ...
/// =>
/// ... one usage of DelegateConstruction ...
/// </summary>
bool CachedDelegateInitializationWithField(IfInstruction inst)
{
Block trueInst = inst.TrueInst as Block;
if (trueInst == null || trueInst.Instructions.Count != 1 || !inst.FalseInst.MatchNop())
{
return(false);
}
var storeInst = trueInst.Instructions[0];
if (!inst.Condition.MatchCompEquals(out ILInstruction left, out ILInstruction right) || !left.MatchLdsFld(out IField field) || !right.MatchLdNull())
{
return(false);
}
if (!storeInst.MatchStsFld(out IField field2, out ILInstruction value) || !field.Equals(field2) || !field.IsCompilerGeneratedOrIsInCompilerGeneratedClass())
{
return(false);
}
if (!DelegateConstruction.IsDelegateConstruction(value as NewObj, true))
{
return(false);
}
var nextInstruction = inst.Parent.Children.ElementAtOrDefault(inst.ChildIndex + 1);
if (nextInstruction == null)
{
return(false);
}
var usages = nextInstruction.Descendants.Where(i => i.MatchLdsFld(field)).ToArray();
if (usages.Length != 1)
{
return(false);
}
context.Step("CachedDelegateInitializationWithField", inst);
usages[0].ReplaceWith(value);
return(true);
}
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);
}
bool DoTransform(Block body, int pos)
{
ILInstruction inst = body.Instructions[pos];
// Match stloc(v, newobj)
if (inst.MatchStLoc(out var v, out var initInst) && (v.Kind == VariableKind.Local || v.Kind == VariableKind.StackSlot))
{
IType instType;
switch (initInst)
{
case NewObj newObjInst:
if (newObjInst.ILStackWasEmpty && v.Kind == VariableKind.Local && !context.Function.Method.IsConstructor && !context.Function.Method.IsCompilerGeneratedOrIsInCompilerGeneratedClass())
{
// on statement level (no other expressions on IL stack),
// prefer to keep local variables (but not stack slots),
// unless we are in a constructor (where inlining object initializers might be critical
// for the base ctor call) or a compiler-generated delegate method, which might be used in a query expression.
return(false);
}
// Do not try to transform display class usages or delegate construction.
// DelegateConstruction transform cannot deal with this.
if (DelegateConstruction.IsSimpleDisplayClass(newObjInst.Method.DeclaringType))
{
return(false);
}
if (DelegateConstruction.IsDelegateConstruction(newObjInst) || DelegateConstruction.IsPotentialClosure(context, newObjInst))
{
return(false);
}
// Cannot build a collection/object initializer attached to an AnonymousTypeCreateExpression:s
// anon = new { A = 5 } { 3,4,5 } is invalid syntax.
if (newObjInst.Method.DeclaringType.ContainsAnonymousType())
{
return(false);
}
instType = newObjInst.Method.DeclaringType;
break;
case DefaultValue defaultVal:
if (defaultVal.ILStackWasEmpty && v.Kind == VariableKind.Local && !context.Function.Method.IsConstructor)
{
// on statement level (no other expressions on IL stack),
// prefer to keep local variables (but not stack slots),
// unless we are in a constructor (where inlining object initializers might be critical
// for the base ctor call)
return(false);
}
instType = defaultVal.Type;
break;
default:
return(false);
}
int initializerItemsCount = 0;
var blockKind = BlockKind.CollectionInitializer;
possibleIndexVariables = new Dictionary <ILVariable, (int Index, ILInstruction Value)>();
currentPath = new List <AccessPathElement>();
isCollection = false;
pathStack = new Stack <HashSet <AccessPathElement> >();
pathStack.Push(new HashSet <AccessPathElement>());
// Detect initializer type by scanning the following statements
// each must be a callvirt with ldloc v as first argument
// if the method is a setter we're dealing with an object initializer
// if the method is named Add and has at least 2 arguments we're dealing with a collection/dictionary initializer
while (pos + initializerItemsCount + 1 < body.Instructions.Count &&
IsPartOfInitializer(body.Instructions, pos + initializerItemsCount + 1, v, instType, ref blockKind))
{
initializerItemsCount++;
}
// Do not convert the statements into an initializer if there's an incompatible usage of the initializer variable
// directly after the possible initializer.
if (IsMethodCallOnVariable(body.Instructions[pos + initializerItemsCount + 1], v))
{
return(false);
}
// Calculate the correct number of statements inside the initializer:
// All index variables that were used in the initializer have Index set to -1.
// We fetch the first unused variable from the list and remove all instructions after its
// first usage (i.e. the init store) from the initializer.
var index = possibleIndexVariables.Where(info => info.Value.Index > -1).Min(info => (int?)info.Value.Index);
if (index != null)
{
initializerItemsCount = index.Value - pos - 1;
}
// The initializer would be empty, there's nothing to do here.
if (initializerItemsCount <= 0)
{
return(false);
}
context.Step("CollectionOrObjectInitializer", inst);
// Create a new block and final slot (initializer target variable)
var initializerBlock = new Block(blockKind);
ILVariable finalSlot = context.Function.RegisterVariable(VariableKind.InitializerTarget, v.Type);
initializerBlock.FinalInstruction = new LdLoc(finalSlot);
initializerBlock.Instructions.Add(new StLoc(finalSlot, initInst.Clone()));
// Move all instructions to the initializer block.
for (int i = 1; i <= initializerItemsCount; i++)
{
switch (body.Instructions[i + pos])
{
case CallInstruction call:
if (!(call is CallVirt || call is Call))
{
continue;
}
var newCall = call;
var newTarget = newCall.Arguments[0];
foreach (var load in newTarget.Descendants.OfType <IInstructionWithVariableOperand>())
{
if ((load is LdLoc || load is LdLoca) && load.Variable == v)
{
load.Variable = finalSlot;
}
}
initializerBlock.Instructions.Add(newCall);
break;
case StObj stObj:
var newStObj = stObj;
foreach (var load in newStObj.Target.Descendants.OfType <IInstructionWithVariableOperand>())
{
if ((load is LdLoc || load is LdLoca) && load.Variable == v)
{
load.Variable = finalSlot;
}
}
initializerBlock.Instructions.Add(newStObj);
break;
case StLoc stLoc:
var newStLoc = stLoc;
initializerBlock.Instructions.Add(newStLoc);
break;
}
}
initInst.ReplaceWith(initializerBlock);
body.Instructions.RemoveRange(pos + 1, initializerItemsCount);
ILInlining.InlineIfPossible(body, pos, context);
}
return(true);
}