void MapGeneratedTypeTypeParameters(MetadataType generatedType)
{
Debug.Assert(CompilerGeneratedNames.IsGeneratedType(generatedType.Name));
Debug.Assert(generatedType == generatedType.GetTypeDefinition());
if (_generatedTypeToTypeArgumentInfo?.TryGetValue(generatedType, out var typeInfo) != true)
{
// This can happen for static (non-capturing) closure environments, where more than
// nested function can map to the same closure environment. Since the current functionality
// is based on a one-to-one relationship between environments (types) and methods, this is
// not supported.
return;
}
if (typeInfo.OriginalAttributes is not null)
{
return;
}
var method = typeInfo.CreatingMethod;
var body = ilProvider.GetMethodIL(method);
var typeArgs = new GenericParameterDesc?[generatedType.Instantiation.Length];
var typeRef = ScanForInit(generatedType, body);
if (typeRef is null)
{
return;
}
// The typeRef is going to be a generic instantiation with signature variables
// We need to figure out the actual generic parameters which were used to create these
// so instantiate the typeRef in the context of the method body where it is created
TypeDesc instantiatedType = typeRef.InstantiateSignature(method.OwningType.Instantiation, method.Instantiation);
for (int i = 0; i < instantiatedType.Instantiation.Length; i++)
{
var typeArg = instantiatedType.Instantiation[i];
// Start with the existing parameters, in case we can't find the mapped one
GenericParameterDesc?userAttrs = generatedType.Instantiation[i] as GenericParameterDesc;
// The type parameters of the state machine types are alpha renames of the
// the method parameters, so the type ref should always be a GenericParameter. However,
// in the case of nesting, there may be multiple renames, so if the parameter is a method
// we know we're done, but if it's another state machine, we have to keep looking to find
// the original owner of that state machine.
if (typeArg is GenericParameterDesc {
Kind: { } kind
} param)
{
if (kind == GenericParameterKind.Method)
{
userAttrs = param;
}
else
{
// Must be a type ref
if (method.OwningType is not MetadataType owningType || !CompilerGeneratedNames.IsGeneratedType(owningType.Name))
{
userAttrs = param;
}
internal TypeCache(MetadataType type, Logger?logger, ILProvider ilProvider)
{
Debug.Assert(type == type.GetTypeDefinition());
Debug.Assert(!CompilerGeneratedNames.IsGeneratedMemberName(type.Name));
Type = type;
var callGraph = new CompilerGeneratedCallGraph();
var userDefinedMethods = new HashSet <MethodDesc>();
void ProcessMethod(MethodDesc method)
{
Debug.Assert(method == method.GetTypicalMethodDefinition());
bool isStateMachineMember = CompilerGeneratedNames.IsStateMachineType(((MetadataType)method.OwningType).Name);
if (!CompilerGeneratedNames.IsLambdaOrLocalFunction(method.Name))
{
if (!isStateMachineMember)
{
// If it's not a nested function, track as an entry point to the call graph.
var added = userDefinedMethods.Add(method);
Debug.Assert(added);
}
}
else
{
// We don't expect lambdas or local functions to be emitted directly into
// state machine types.
Debug.Assert(!isStateMachineMember);
}
// Discover calls or references to lambdas or local functions. This includes
// calls to local functions, and lambda assignments (which use ldftn).
var methodBody = ilProvider.GetMethodIL(method);
if (methodBody != null)
{
ILReader reader = new ILReader(methodBody.GetILBytes());
while (reader.HasNext)
{
ILOpcode opcode = reader.ReadILOpcode();
switch (opcode)
{
case ILOpcode.ldftn:
case ILOpcode.ldtoken:
case ILOpcode.call:
case ILOpcode.callvirt:
case ILOpcode.newobj:
{
MethodDesc?referencedMethod = methodBody.GetObject(reader.ReadILToken(), NotFoundBehavior.ReturnNull) as MethodDesc;
if (referencedMethod == null)
{
continue;
}
referencedMethod = referencedMethod.GetTypicalMethodDefinition();
if (referencedMethod.IsConstructor &&
referencedMethod.OwningType is MetadataType generatedType &&
// Don't consider calls in the same type, like inside a static constructor
method.OwningType != generatedType &&
CompilerGeneratedNames.IsLambdaDisplayClass(generatedType.Name))
{
Debug.Assert(generatedType.IsTypeDefinition);
// fill in null for now, attribute providers will be filled in later
_generatedTypeToTypeArgumentInfo ??= new Dictionary <MetadataType, TypeArgumentInfo>();
if (!_generatedTypeToTypeArgumentInfo.TryAdd(generatedType, new TypeArgumentInfo(method, null)))
{
var alreadyAssociatedMethod = _generatedTypeToTypeArgumentInfo[generatedType].CreatingMethod;
logger?.LogWarning(new MessageOrigin(method), DiagnosticId.MethodsAreAssociatedWithUserMethod, method.GetDisplayName(), alreadyAssociatedMethod.GetDisplayName(), generatedType.GetDisplayName());
}
continue;
}
if (!CompilerGeneratedNames.IsLambdaOrLocalFunction(referencedMethod.Name))
{
continue;
}
if (isStateMachineMember)
{
callGraph.TrackCall((MetadataType)method.OwningType, referencedMethod);
}
else
{
callGraph.TrackCall(method, referencedMethod);
}
}
break;
case ILOpcode.stsfld:
{
// Same as above, but stsfld instead of a call to the constructor
FieldDesc?field = methodBody.GetObject(reader.ReadILToken()) as FieldDesc;
if (field == null)
{
continue;
}
field = field.GetTypicalFieldDefinition();
if (field.OwningType is MetadataType generatedType &&
// Don't consider field accesses in the same type, like inside a static constructor
method.OwningType != generatedType &&
CompilerGeneratedNames.IsLambdaDisplayClass(generatedType.Name))
{
Debug.Assert(generatedType.IsTypeDefinition);
_generatedTypeToTypeArgumentInfo ??= new Dictionary <MetadataType, TypeArgumentInfo>();
if (!_generatedTypeToTypeArgumentInfo.TryAdd(generatedType, new TypeArgumentInfo(method, null)))
{
// It's expected that there may be multiple methods associated with the same static closure environment.
// All of these methods will substitute the same type arguments into the closure environment
// (if it is generic). Don't warn.
}
continue;
}
}
break;
default:
reader.Skip(opcode);
break;
}
}
}
if (TryGetStateMachineType(method, out MetadataType? stateMachineType))
{
Debug.Assert(stateMachineType.ContainingType == type ||
(CompilerGeneratedNames.IsGeneratedMemberName(stateMachineType.ContainingType.Name) &&
stateMachineType.ContainingType.ContainingType == type));
Debug.Assert(stateMachineType == stateMachineType.GetTypeDefinition());
callGraph.TrackCall(method, stateMachineType);
_compilerGeneratedTypeToUserCodeMethod ??= new Dictionary <MetadataType, MethodDesc>();
if (!_compilerGeneratedTypeToUserCodeMethod.TryAdd(stateMachineType, method))
{
var alreadyAssociatedMethod = _compilerGeneratedTypeToUserCodeMethod[stateMachineType];
logger?.LogWarning(new MessageOrigin(method), DiagnosticId.MethodsAreAssociatedWithStateMachine, method.GetDisplayName(), alreadyAssociatedMethod.GetDisplayName(), stateMachineType.GetDisplayName());
}
// Already warned above if multiple methods map to the same type
// Fill in null for argument providers now, the real providers will be filled in later
_generatedTypeToTypeArgumentInfo ??= new Dictionary <MetadataType, TypeArgumentInfo>();
_generatedTypeToTypeArgumentInfo[stateMachineType] = new TypeArgumentInfo(method, null);
}
}
// Look for state machine methods, and methods which call local functions.
foreach (MethodDesc method in type.GetMethods())
{
ProcessMethod(method);
}
// Also scan compiler-generated state machine methods (in case they have calls to nested functions),
// and nested functions inside compiler-generated closures (in case they call other nested functions).
// State machines can be emitted into lambda display classes, so we need to go down at least two
// levels to find calls from iterator nested functions to other nested functions. We just recurse into
// all compiler-generated nested types to avoid depending on implementation details.
foreach (var nestedType in GetCompilerGeneratedNestedTypes(type))
{
foreach (var method in nestedType.GetMethods())
{
ProcessMethod(method);
}
}
// Now we've discovered the call graphs for calls to nested functions.
// Use this to map back from nested functions to the declaring user methods.
// Note: This maps all nested functions back to the user code, not to the immediately
// declaring local function. The IL doesn't contain enough information in general for
// us to determine the nesting of local functions and lambdas.
// Note: this only discovers nested functions which are referenced from the user
// code or its referenced nested functions. There is no reliable way to determine from
// IL which user code an unused nested function belongs to.
foreach (var userDefinedMethod in userDefinedMethods)
{
var callees = callGraph.GetReachableMembers(userDefinedMethod);
if (!callees.Any())
{
continue;
}
_compilerGeneratedMembers ??= new Dictionary <MethodDesc, List <TypeSystemEntity> >();
_compilerGeneratedMembers.Add(userDefinedMethod, new List <TypeSystemEntity>(callees));
foreach (var compilerGeneratedMember in callees)
{
switch (compilerGeneratedMember)
{
case MethodDesc nestedFunction:
Debug.Assert(CompilerGeneratedNames.IsLambdaOrLocalFunction(nestedFunction.Name));
// Nested functions get suppressions from the user method only.
_compilerGeneratedMethodToUserCodeMethod ??= new Dictionary <MethodDesc, MethodDesc>();
if (!_compilerGeneratedMethodToUserCodeMethod.TryAdd(nestedFunction, userDefinedMethod))
{
var alreadyAssociatedMethod = _compilerGeneratedMethodToUserCodeMethod[nestedFunction];
logger?.LogWarning(new MessageOrigin(userDefinedMethod), DiagnosticId.MethodsAreAssociatedWithUserMethod, userDefinedMethod.GetDisplayName(), alreadyAssociatedMethod.GetDisplayName(), nestedFunction.GetDisplayName());
}
break;
case MetadataType stateMachineType:
// Types in the call graph are always state machine types
// For those all their methods are not tracked explicitly in the call graph; instead, they
// are represented by the state machine type itself.
// We are already tracking the association of the state machine type to the user code method
// above, so no need to track it here.
Debug.Assert(CompilerGeneratedNames.IsStateMachineType(stateMachineType.Name));
break;
default:
throw new InvalidOperationException();
}
}
}
// Now that we have instantiating methods fully filled out, walk the generated types and fill in the attribute
// providers
if (_generatedTypeToTypeArgumentInfo != null)
{
foreach (var generatedType in _generatedTypeToTypeArgumentInfo.Keys)
{
Debug.Assert(generatedType == generatedType.GetTypeDefinition());
if (HasGenericParameters(generatedType))
{
MapGeneratedTypeTypeParameters(generatedType);
}
}
}
