Account for whether artificial subclasses are skipped on type caching

MetadataReader caches types only with the metadata address as the key.
However a type lookup can be requested skipping artificial subclasses or
not. This makes the cached results incorrect if two requests for the
same type, but skipping subclasses on one and not on the other, are made.
Fix this by adding a second dimension to the cache key.

rdar://101519300

Author: augusto2112

include/swift/Remote/MetadataReader.h

@@ -17,6 +17,8 @@
 #ifndef SWIFT_REMOTE_METADATAREADER_H
 #define SWIFT_REMOTE_METADATAREADER_H
 
+#include "llvm/ADT/Hashing.h"
+
 #include "swift/Runtime/Metadata.h"
 #include "swift/Remote/MemoryReader.h"
 #include "swift/Demangling/Demangler.h"
@@ -193,8 +195,18 @@ class MetadataReader {
   /// amounts of data when we encounter corrupt values for sizes/counts.
   static const uint64_t MaxMetadataSize = 1048576; // 1MB
 
-  /// A cache of built types, keyed by the address of the type.
-  std::unordered_map<StoredPointer, BuiltType> TypeCache;
+  /// Define a has function for a std::pair<StoredPointer, bool>
+  struct TypeCacheKeyHash {
+    std::size_t operator()(const std::pair<StoredPointer, bool> &x) const {
+      return llvm::hash_combine(x.first, x.second);
+    }
+  };
+
+  /// A cache of built types, keyed by the address of the type and whether the
+  /// request ignored articial superclasses or not.
+  std::unordered_map<std::pair<StoredPointer, bool>, BuiltType,
+                     TypeCacheKeyHash>
+      TypeCache;
 
   using MetadataRef = RemoteRef<const TargetMetadata<Runtime>>;
   using OwnedMetadataRef = MemoryReader::ReadBytesResult;
@@ -821,7 +833,9 @@ class MetadataReader {
   readTypeFromMetadata(StoredPointer MetadataAddress,
                        bool skipArtificialSubclasses = false,
                        int recursion_limit = defaultTypeRecursionLimit) {
-    auto Cached = TypeCache.find(MetadataAddress);
+    std::pair<StoredPointer, bool> TypeCacheKey(MetadataAddress,
+                                                skipArtificialSubclasses);
+    auto Cached = TypeCache.find(TypeCacheKey);
     if (Cached != TypeCache.end())
       return Cached->second;
 
@@ -841,7 +855,7 @@ class MetadataReader {
     // Insert a negative result into the cache now so that, if we recur with
     // the same address, we will return the negative result with the check
     // just above.
-    TypeCache.insert({MetadataAddress, BuiltType()});
+    TypeCache.insert({TypeCacheKey, BuiltType()});
 
     auto Meta = readMetadata(MetadataAddress);
     if (!Meta) return BuiltType();
@@ -890,7 +904,7 @@ class MetadataReader {
 
       auto BuiltTuple =
           Builder.createTupleType(elementTypes, labels);
-      TypeCache[MetadataAddress] = BuiltTuple;
+      TypeCache[TypeCacheKey] = BuiltTuple;
       return BuiltTuple;
     }
     case MetadataKind::Function: {
@@ -947,7 +961,7 @@ class MetadataReader {
 
       auto BuiltFunction = Builder.createFunctionType(
           Parameters, Result, flags, diffKind, globalActor);
-      TypeCache[MetadataAddress] = BuiltFunction;
+      TypeCache[TypeCacheKey] = BuiltFunction;
       return BuiltFunction;
     }
     case MetadataKind::Existential: {
@@ -998,7 +1012,7 @@ class MetadataReader {
       }
       auto BuiltExist = Builder.createProtocolCompositionType(
         Protocols, SuperclassType, HasExplicitAnyObject);
-      TypeCache[MetadataAddress] = BuiltExist;
+      TypeCache[TypeCacheKey] = BuiltExist;
       return BuiltExist;
     }
     case MetadataKind::ExtendedExistential: {
@@ -1076,7 +1090,7 @@ class MetadataReader {
         }
       }
 
-      TypeCache[MetadataAddress] = builtProto;
+      TypeCache[TypeCacheKey] = builtProto;
       return builtProto;
     }
 
@@ -1086,7 +1100,7 @@ class MetadataReader {
           readTypeFromMetadata(Metatype->InstanceType, false, recursion_limit);
       if (!Instance) return BuiltType();
       auto BuiltMetatype = Builder.createMetatypeType(Instance);
-      TypeCache[MetadataAddress] = BuiltMetatype;
+      TypeCache[TypeCacheKey] = BuiltMetatype;
       return BuiltMetatype;
     }
     case MetadataKind::ObjCClassWrapper: {
@@ -1098,7 +1112,7 @@ class MetadataReader {
         return BuiltType();
 
       auto BuiltObjCClass = Builder.createObjCClassType(std::move(className));
-      TypeCache[MetadataAddress] = BuiltObjCClass;
+      TypeCache[TypeCacheKey] = BuiltObjCClass;
       return BuiltObjCClass;
     }
     case MetadataKind::ExistentialMetatype: {
@@ -1107,7 +1121,7 @@ class MetadataReader {
           readTypeFromMetadata(Exist->InstanceType, false, recursion_limit);
       if (!Instance) return BuiltType();
       auto BuiltExist = Builder.createExistentialMetatypeType(Instance);
-      TypeCache[MetadataAddress] = BuiltExist;
+      TypeCache[TypeCacheKey] = BuiltExist;
       return BuiltExist;
     }
     case MetadataKind::ForeignReferenceType:
@@ -1131,7 +1145,7 @@ class MetadataReader {
       auto name = mangling.result();
 
       auto BuiltForeign = Builder.createForeignClassType(std::move(name));
-      TypeCache[MetadataAddress] = BuiltForeign;
+      TypeCache[TypeCacheKey] = BuiltForeign;
       return BuiltForeign;
     }
     case MetadataKind::HeapLocalVariable:
@@ -1142,7 +1156,7 @@ class MetadataReader {
     case MetadataKind::Opaque:
     default: {
       auto BuiltOpaque = Builder.getOpaqueType();
-      TypeCache[MetadataAddress] = BuiltOpaque;
+      TypeCache[TypeCacheKey] = BuiltOpaque;
       return BuiltOpaque;
     }
     }
@@ -3084,9 +3098,12 @@ class MetadataReader {
     // If we've skipped an artificial subclasses, check the cache at
     // the superclass.  (This also protects against recursion.)
     if (skipArtificialSubclasses && metadata != origMetadata) {
-      auto it = TypeCache.find(getAddress(metadata));
-      if (it != TypeCache.end())
+      auto it =
+          TypeCache.find({getAddress(metadata), skipArtificialSubclasses});
+      if (it != TypeCache.end()) {
+        TypeCache.erase({getAddress(origMetadata), skipArtificialSubclasses});
         return it->second;
+      }
     }
 
     // Read the nominal type descriptor.
@@ -3115,12 +3132,12 @@ class MetadataReader {
     if (!nominal)
       return BuiltType();
 
-    TypeCache[getAddress(metadata)] = nominal;
+    TypeCache[{getAddress(metadata), skipArtificialSubclasses}] = nominal;
 
     // If we've skipped an artificial subclass, remove the
     // recursion-protection entry we made for it.
     if (skipArtificialSubclasses && metadata != origMetadata) {
-      TypeCache.erase(getAddress(origMetadata));
+      TypeCache.erase({getAddress(origMetadata), skipArtificialSubclasses});
     }
 
     return nominal;
@@ -3151,7 +3168,7 @@ class MetadataReader {
                                skipArtificialSubclasses, recursion_limit);
     }
 
-    TypeCache[origMetadataPtr] = BuiltObjCClass;
+    TypeCache[{origMetadataPtr, skipArtificialSubclasses}] = BuiltObjCClass;
     return BuiltObjCClass;
   }