Merge pull request #28869 from DougGregor/assoc-type-witness-canon

[IRGen] Canonicalize associated type witnesses.

Author: DougGregor

lib/IRGen/GenMeta.cpp

@@ -824,6 +824,7 @@ namespace {
         auto witness =
             entry.getAssociatedTypeWitness().Witness->mapTypeOutOfContext();
         return IGM.getAssociatedTypeWitness(witness,
+                                            Proto->getGenericSignature(),
                                             /*inProtocolContext=*/true);
       }
 
@@ -1593,8 +1594,7 @@ namespace {
       // TargetRelativeDirectPointer<Runtime, const char> SuperclassType;
       if (auto superclassType = getType()->getSuperclass()) {
         GenericSignature genericSig = getType()->getGenericSignature();
-        B.addRelativeAddress(IGM.getTypeRef(superclassType->getCanonicalType(),
-                                            genericSig,
+        B.addRelativeAddress(IGM.getTypeRef(superclassType, genericSig,
                                             MangledTypeRefRole::Metadata)
                                .first);
       } else {

lib/IRGen/GenProto.cpp

@@ -1303,7 +1303,10 @@ class AccessorConformanceInfo : public ConformanceInfo {
       auto associate =
           Conformance.getTypeWitness(requirement.getAssociation());
       llvm::Constant *witness =
-          IGM.getAssociatedTypeWitness(associate, /*inProtocolContext=*/false);
+          IGM.getAssociatedTypeWitness(
+            associate,
+            Conformance.getDeclContext()->getGenericSignatureOfContext(),
+            /*inProtocolContext=*/false);
       Table.addBitCast(witness, IGM.Int8PtrTy);
     }
 
@@ -1436,6 +1439,7 @@ void WitnessTableBuilder::build() {
 }
 
 llvm::Constant *IRGenModule::getAssociatedTypeWitness(Type type,
+                                                      GenericSignature sig,
                                                       bool inProtocolContext) {
   // FIXME: If we can directly reference constant type metadata, do so.
 
@@ -1444,7 +1448,7 @@ llvm::Constant *IRGenModule::getAssociatedTypeWitness(Type type,
   auto role = inProtocolContext
     ? MangledTypeRefRole::DefaultAssociatedTypeWitness
     : MangledTypeRefRole::Metadata;
-  auto typeRef = getTypeRef(type, /*generic signature*/nullptr, role).first;
+  auto typeRef = getTypeRef(type, sig, role).first;
 
   // Set the low bit to indicate that this is a mangled name.
   auto witness = llvm::ConstantExpr::getPtrToInt(typeRef, IntPtrTy);
@@ -1613,7 +1617,10 @@ void WitnessTableBuilder::collectResilientWitnesses(
       auto associate = conformance.getTypeWitness(assocType);
 
       llvm::Constant *witness =
-          IGM.getAssociatedTypeWitness(associate, /*inProtocolContext=*/false);
+          IGM.getAssociatedTypeWitness(
+            associate,
+            conformance.getDeclContext()->getGenericSignatureOfContext(),
+            /*inProtocolContext=*/false);
       resilientWitnesses.push_back(witness);
       continue;
     }

lib/IRGen/IRGenModule.h

@@ -1123,7 +1123,8 @@ class IRGenModule {
                                          CanGenericSignature genericSig);
 
   /// Produce an associated type witness that refers to the given type.
-  llvm::Constant *getAssociatedTypeWitness(Type type, bool inProtocolContext);
+  llvm::Constant *getAssociatedTypeWitness(Type type, GenericSignature sig,
+                                           bool inProtocolContext);
 
   void emitAssociatedTypeMetadataRecord(const RootProtocolConformance *C);
   void emitFieldDescriptor(const NominalTypeDecl *Decl);

test/IRGen/associated_type_witness.swift

@@ -133,6 +133,37 @@ struct UsesVoid : HasSimpleAssoc {
   typealias Assoc = ()
 }
 
+// SR-11642: Failure to canonicalize type in associated type witness.
+struct Validator<T> {
+  let validatorFailureType: Any.Type
+}
+
+
+protocol ValidatorType {
+  associatedtype Data
+  associatedtype Failure
+  func validator() -> Validator<Data>
+}
+
+
+extension ValidatorType {
+  func validator() -> Validator<Data> {
+    .init(validatorFailureType: Failure.self)
+  }
+}
+
+
+// MARK: Failing example
+extension Validator where T == String {
+  // GLOBAL: @"symbolic _____ySS__G 23associated_type_witness9ValidatorVAASSRszlE1VV7FailureV"
+  struct V: ValidatorType {
+    typealias Data = T // or String
+
+    struct Failure {}
+  }
+}
+
+
 //   Protocol conformance descriptor for Computed : Assocked.
 // GLOBAL-LABEL: @"$s23associated_type_witness8ComputedVyxq_GAA8AssockedAAMc" = hidden constant
 // GLOBAL-SAME:    i16 4,