[cxx-interop][Runtime] Initialize metadata of a Swift array of C++ references correctly

This fixes a crash at runtime when destroying a Swift array of values of a C++ foreign reference type.

Swift optimizes the amount of metadata emitted for `_ContiguousArrayStorage<Element>` by reusing `_ContiguousArrayStorage<AnyObject>` whenever possible (see `getContiguousArrayStorageType`). However, C++ foreign reference types are not `AnyObject`s, since they have custom retain/release operations.

This change disables the `_ContiguousArrayStorage` metadata optimization for C++ reference types, which makes sure that `swift_arrayDestroy` will call the correct release operation for elements of `[MyCxxRefType]`.

rdar://127154770

Author: egorzhdan

include/swift/ABI/Metadata.h

@@ -297,7 +297,6 @@ struct TargetMetadata {
     case MetadataKind::Class:
     case MetadataKind::ObjCClassWrapper:
     case MetadataKind::ForeignClass:
-    case MetadataKind::ForeignReferenceType:
       return true;
 
     default:

test/Interop/Cxx/foreign-reference/not-any-object.swift

@@ -15,7 +15,9 @@ module Test {
 
 inline void* operator new(unsigned long, void* p) { return p; }
 
-struct __attribute__((swift_attr("import_reference"))) Empty {
+struct __attribute__((swift_attr("import_reference")))
+       __attribute__((swift_attr("retain:immortal")))
+       __attribute__((swift_attr("release:immortal"))) Empty {
   static Empty *create() { return new (malloc(sizeof(Empty))) Empty(); }
 };
 
@@ -27,3 +29,4 @@ public func test(_ _: AnyObject) {}
 
 // TODO: make this a better error.
 test(Empty.create()) // expected-error {{type of expression is ambiguous without a type annotation}}
+test([Empty.create()][0]) // expected-error {{argument type 'Any' expected to be an instance of a class or class-constrained type}}

test/Interop/Cxx/foreign-reference/reference-counted-irgen.swift

@@ -51,3 +51,17 @@ public func getNullable(wantNullptr: Bool) -> GlobalCountNullableInit? {
 // CHECK:      lifetime.cont:
 // CHECK:          ret i64 %2
 // CHECK-NEXT: }
+
+
+public func getArrayOfLocalCount() -> [NS.LocalCount] {
+    return [NS.LocalCount.create()]
+}
+
+// CHECK:      define {{.*}}swiftcc ptr @"$s4main20getArrayOfLocalCountSaySo2NSO0eF0VGyF"()
+// CHECK-NEXT: entry:
+// CHECK-NEXT:   %0 = call swiftcc %swift.metadata_response @"$sSo2NSO10LocalCountVMa"(i64 0) #9
+// CHECK-NEXT:   %1 = extractvalue %swift.metadata_response %0, 0
+// CHECK-NEXT:   %2 = call swiftcc { ptr, ptr } @"$ss27_allocateUninitializedArrayySayxG_BptBwlF"(i64 1, ptr %1)
+// CHECK:        %5 = call ptr @{{_ZN2NS10LocalCount6createEv|"\?create\@LocalCount\@NS\@\@SAPEAU12\@XZ"}}()
+// CHECK-NEXT:   call void @{{_Z8LCRetainPN2NS10LocalCountE|"\?LCRetain\@\@YAXPEAULocalCount\@NS\@\@\@Z"}}(ptr %5)
+// CHECK:      }

test/Interop/Cxx/foreign-reference/reference-counted.swift

@@ -67,4 +67,18 @@ ReferenceCountedTestSuite.test("Global") {
     expectEqual(globalCount, 0)
 }
 
+var globalArray: [GlobalCount] = []
+
+ReferenceCountedTestSuite.test("Global array") {
+    expectEqual(globalCount, 0)
+
+    globalArray = [GlobalCount.create()]
+#if NO_OPTIMIZATIONS
+    expectEqual(globalCount, 1)
+#endif
+
+    globalArray = []
+    expectEqual(globalCount, 0)
+}
+
 runAllTests()