Use the same behavior of a non-frozen public decl for a package decl

in a resiliency check, i.e. *Decl::isFormallyResilient.

If the defining module is built resiliently, treat the package decl as resilient.

Added tests to check for serialization and indirect access with/out resilience enabled.

Ref rdar://118947451

Author: elsh

include/swift/AST/AccessScope.h

@@ -75,6 +75,7 @@ class AccessScope {
   bool isFileScope() const;
   bool isInternal() const;
   bool isPackage() const;
+  bool isPublicOrPackage() const { return isPublic() || isPackage(); }
 
   /// Checks if the DeclContext of this (use site) access scope is more
   /// restrictive than that of the argument (decl site) based on the DeclContext

lib/AST/Decl.cpp

@@ -2986,7 +2986,7 @@ bool AbstractStorageDecl::isFormallyResilient() const {
   // Non-public global and static variables always have a
   // fixed layout.
   if (!getFormalAccessScope(/*useDC=*/nullptr,
-                            /*treatUsableFromInlineAsPublic=*/true).isPublic())
+                            /*treatUsableFromInlineAsPublic=*/true).isPublicOrPackage())
     return false;
 
   return true;
@@ -4987,10 +4987,10 @@ int TypeDecl::compare(const TypeDecl *type1, const TypeDecl *type2) {
 }
 
 bool NominalTypeDecl::isFormallyResilient() const {
-  // Private, (unversioned) internal, and package types always have a
+  // Private and (unversioned) internal types always have a
   // fixed layout.
   if (!getFormalAccessScope(/*useDC=*/nullptr,
-                            /*treatUsableFromInlineAsPublic=*/true).isPublic())
+                            /*treatUsableFromInlineAsPublic=*/true).isPublicOrPackage())
     return false;
 
   // Check for an explicit @_fixed_layout or @frozen attribute.

test/SILGen/witness_tables_serialized.swift

@@ -26,11 +26,6 @@ internal struct UsableFromInlineStruct : PublicProtocol, UsableFromInlineProtoco
 // CHECK-DAG: sil_witness_table PublicFrozenStruct: PackageProtocol
 // CHECK-DAG: sil_witness_table hidden PublicFrozenStruct: InternalProtocol
 
-// CHECK-DAG: sil_witness_table [serialized] PackageStruct: PublicProtocol
-// CHECK-DAG: sil_witness_table [serialized] PackageStruct: UsableFromInlineProtocol
-// CHECK-DAG: sil_witness_table PackageStruct: PackageProtocol
-// CHECK-DAG: sil_witness_table hidden PackageStruct: InternalProtocol
-
 // CHECK-RESILIENT-DAG: sil_witness_table UsableFromInlineStruct: UsableFromInlineProtocol
 // CHECK-RESILIENT-DAG: sil_witness_table UsableFromInlineStruct: PublicProtocol
 // CHECK-RESILIENT-DAG: sil_witness_table UsableFromInlineStruct: PackageProtocol
@@ -41,6 +36,11 @@ internal struct UsableFromInlineStruct : PublicProtocol, UsableFromInlineProtoco
 // CHECK-RESILIENT-DAG: sil_witness_table PublicResilientStruct: PackageProtocol
 // CHECK-RESILIENT-DAG: sil_witness_table hidden PublicResilientStruct: InternalProtocol
 
+// CHECK-RESILIENT-DAG: sil_witness_table PackageStruct: PublicProtocol
+// CHECK-RESILIENT-DAG: sil_witness_table PackageStruct: UsableFromInlineProtocol
+// CHECK-RESILIENT-DAG: sil_witness_table PackageStruct: PackageProtocol
+// CHECK-RESILIENT-DAG: sil_witness_table hidden PackageStruct: InternalProtocol
+
 // CHECK-NONRESILIENT-DAG: sil_witness_table [serialized] UsableFromInlineStruct: UsableFromInlineProtocol
 // CHECK-NONRESILIENT-DAG: sil_witness_table [serialized] UsableFromInlineStruct: PublicProtocol
 // CHECK-NONRESILIENT-DAG: sil_witness_table UsableFromInlineStruct: PackageProtocol
@@ -50,3 +50,8 @@ internal struct UsableFromInlineStruct : PublicProtocol, UsableFromInlineProtoco
 // CHECK-NONRESILIENT-DAG: sil_witness_table [serialized] PublicResilientStruct: UsableFromInlineProtocol
 // CHECK-NONRESILIENT-DAG: sil_witness_table PublicResilientStruct: PackageProtocol
 // CHECK-NONRESILIENT-DAG: sil_witness_table hidden PublicResilientStruct: InternalProtocol
+
+// CHECK-NONRESILIENT-DAG: sil_witness_table [serialized] PackageStruct: PublicProtocol
+// CHECK-NONRESILIENT-DAG: sil_witness_table [serialized] PackageStruct: UsableFromInlineProtocol
+// CHECK-NONRESILIENT-DAG: sil_witness_table PackageStruct: PackageProtocol
+// CHECK-NONRESILIENT-DAG: sil_witness_table hidden PackageStruct: InternalProtocol