Reserve a larger range for enumerated metadata kinds.

0...128 is pretty meager, and it would be pretty embarrassing to run out.

Author: rjmccall

include/swift/ABI/MetadataKind.def

@@ -83,10 +83,8 @@ METADATAKIND(HeapGenericLocalVariable, 65)
 /// A native error object.
 METADATAKIND(ErrorObject, 128)
 
-/// All metadata kinds in this range are non-isa metadata. Any "metadata" values
-/// outside of this range are objective-c class isa pointers. These isa pointers
-/// are of course not "true" swift metadata.
-ABSTRACTMETADATAKIND(NonIsaMetadata, Class, ErrorObject)
+// getEnumeratedMetadataKind assumes that all the enumerated values here
+// will be <= LastEnumeratedMetadataKind.
 
 #undef ABSTRACTMETADATAKIND
 #undef NOMINALTYPEMETADATAKIND

include/swift/ABI/MetadataValues.h

@@ -39,12 +39,12 @@ enum class MetadataKind : uint32_t {
 #include "MetadataKind.def"
 };
 
+const unsigned LastEnumeratedMetadataKind = 2047;
+
 /// Try to translate the 'isa' value of a type/heap metadata into a value
 /// of the MetadataKind enum.
-template <typename StoredPointer>
-MetadataKind getEnumeratedMetadataKind(StoredPointer kind) {
-  if (kind > static_cast<StoredPointer>(MetadataKind::NonIsaMetadata_End) ||
-      kind < static_cast<StoredPointer>(MetadataKind::NonIsaMetadata_Start))
+inline MetadataKind getEnumeratedMetadataKind(uint64_t kind) {
+  if (kind > LastEnumeratedMetadataKind)
     return MetadataKind::Class;
   return MetadataKind(kind);
 }