[Index] Add symbol properties to record the Swift access level of a declaration

This will allow us to record the access level of a Swift symbol in the index store.

rdar://163256878

Author: ahoppen

clang/include/clang/Index/IndexSymbol.h

@@ -110,19 +110,38 @@ enum class SymbolSubKind : uint8_t {
 typedef uint32_t SymbolPropertySet;
 /// Set of properties that provide additional info about a symbol.
 enum class SymbolProperty : SymbolPropertySet {
-  Generic                       = 1 << 0,
+  Generic = 1 << 0,
   TemplatePartialSpecialization = 1 << 1,
-  TemplateSpecialization        = 1 << 2,
-  UnitTest                      = 1 << 3,
-  IBAnnotated                   = 1 << 4,
-  IBOutletCollection            = 1 << 5,
-  GKInspectable                 = 1 << 6,
-  Local                         = 1 << 7,
+  TemplateSpecialization = 1 << 2,
+  UnitTest = 1 << 3,
+  IBAnnotated = 1 << 4,
+  IBOutletCollection = 1 << 5,
+  GKInspectable = 1 << 6,
+  Local = 1 << 7,
   /// Symbol is part of a protocol interface.
-  ProtocolInterface             = 1 << 8,
-
-  /// Swift-only properties
-  SwiftAsync                    = 1 << 16,
+  ProtocolInterface = 1 << 8,
+
+  /// --- Swift-only properties
+
+  /// Whether this is a `async` function.
+  SwiftAsync = 1 << 16,
+
+  /// Swift Access control levels, packed into 3 bits.
+  ///
+  /// Use \c applyForEachSymbolProperty to correctly unpack these from a \c
+  /// SymbolPropertySet.
+  SwiftAccessControlPrivate = 1 << 17,
+  SwiftAccessControlFilePrivate = 1 << 18,
+  SwiftAccessControlInternal = 1 << 18 | 1 << 17,
+  SwiftAccessControlPackage = 1 << 19,
+  SwiftAccessControlPublic = 1 << 19 | 1 << 17,
+  SwiftAccessControlOpen = 1 << 19 | 1 << 18,
+
+  /// Whether the declaration has a `@_spi` attributed.
+  ///
+  /// Note that `@_spi` is orthogonal to the access control levels because it
+  /// can be applied to `public` and `open` declarations.
+  SwiftSPI = 1 << 20,
 };
 
 /// Set of roles that are attributed to symbol occurrences.

clang/lib/Index/IndexSymbol.cpp

@@ -603,8 +603,14 @@ void index::applyForEachSymbolProperty(SymbolPropertySet Props,
   APPLY_FOR_PROPERTY(Local);
   APPLY_FOR_PROPERTY(ProtocolInterface);
   APPLY_FOR_PROPERTY(SwiftAsync);
-
+  APPLY_FOR_PROPERTY(SwiftSPI);
+    
 #undef APPLY_FOR_PROPERTY
+
+  /// Access levels are bit-packed, so we need to handle them explicitly.
+  if (uint32_t AccessLevel = Props & (1 << 19 | 1 << 18 | 1 << 17)) {
+    Fn((SymbolProperty)AccessLevel);
+  }
 }
 
 void index::printSymbolProperties(SymbolPropertySet Props, raw_ostream &OS) {
@@ -625,6 +631,13 @@ void index::printSymbolProperties(SymbolPropertySet Props, raw_ostream &OS) {
     case SymbolProperty::Local: OS << "local"; break;
     case SymbolProperty::ProtocolInterface: OS << "protocol"; break;
     case SymbolProperty::SwiftAsync: OS << "swift_async"; break;
+    case SymbolProperty::SwiftAccessControlPrivate: OS << "private"; break;
+    case SymbolProperty::SwiftAccessControlFilePrivate: OS << "fileprivate"; break;
+    case SymbolProperty::SwiftAccessControlInternal: OS << "internal"; break;
+    case SymbolProperty::SwiftAccessControlPackage: OS << "package"; break;
+    case SymbolProperty::SwiftAccessControlPublic: OS << "public"; break;
+    case SymbolProperty::SwiftAccessControlOpen: OS << "open"; break;
+    case SymbolProperty::SwiftSPI: OS << "SPI"; break;
     }
   });
 }