[embedded] Add support for some foreign metadata

test/embedded/Inputs/existential_foreign.h

@@ -0,0 +1,34 @@
+#pragma once
+
+typedef struct {
+  unsigned long long f1;
+  unsigned long long f2;
+} SomeCStruct;
+
+static inline SomeCStruct createSomeCStruct() {
+    SomeCStruct s;
+    s.f1 = 1;
+    s.f2 = 2;
+    return s;
+}
+
+typedef enum {
+  caseA,
+  caseB,
+  caseC
+} SomeCEnum;
+
+static inline SomeCEnum createSomeCEnum() {
+  return caseA;
+}
+
+#define SWIFT_ENUM(_type, _name) enum _name : _type
+
+typedef SWIFT_ENUM(unsigned short, SomeNSEnum) {
+  someCaseA,
+  someCaseB,
+} SomeNSEnum;
+
+static inline SomeNSEnum createSomeNSEnum() {
+  return someCaseB;
+}

test/embedded/existential_foreign.swift

@@ -0,0 +1,102 @@
+// RUN: %target-run-simple-swift(-import-objc-header %S/Inputs/existential_foreign.h -enable-experimental-feature EmbeddedExistentials -enable-experimental-feature Embedded -parse-as-library -wmo) | %FileCheck %s --check-prefix=OUTPUT
+// RUN: %target-run-simple-swift(-import-objc-header %S/Inputs/existential_foreign.h -enable-experimental-feature EmbeddedExistentials -enable-experimental-feature Embedded -parse-as-library -wmo -O) | %FileCheck %s --check-prefix=OUTPUT
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_EmbeddedExistentials
+
+protocol P {
+  func printme()
+}
+
+protocol Q {
+  associatedtype Printable : P
+
+  func getPrintable() -> Printable
+}
+
+extension SomeCStruct : P {
+  func printme() {
+    print("SomeCStruct: \(self.f1), \(self.f2)")
+  }
+}
+
+extension SomeCEnum : P {
+  func printme() {
+    switch self {
+      case caseA:
+        print("SomeCEnum: .caseA")
+      case caseB:
+        print("SomeCEnum: .caseB")
+      case caseC:
+        print("SomeCEnum: .caseC")
+      default:
+        print("SomeCEnum: default")
+    }
+  }
+}
+
+struct SomeCStructContainer : Q {
+  let s: SomeCStruct
+
+  init() {
+    self.s = createSomeCStruct()
+  }
+
+  func getPrintable() -> SomeCStruct {
+    return s
+  }
+}
+
+struct SomeCEnumContainer : Q {
+  let s: SomeCEnum
+
+  init() {
+    self.s = createSomeCEnum()
+  }
+
+  func getPrintable() -> SomeCEnum {
+    return s
+  }
+}
+
+extension SomeNSEnum : P {
+  func printme() {
+    switch self {
+      case .someCaseA:
+        print("SomeNSEnum: .someCaseA")
+      case .someCaseB:
+        print("SomeNSEnum: .someCaseB")
+    }
+  }
+}
+
+struct SomeNSEnumContainer : Q {
+  let s: SomeNSEnum
+
+  init() {
+    self.s = createSomeNSEnum()
+  }
+
+  func getPrintable() -> SomeNSEnum {
+    return s
+  }
+}
+
+@main
+struct Main {
+  static func main() {
+
+    let a: [any Q] = [ SomeCStructContainer(), SomeCEnumContainer(), SomeNSEnumContainer() ]
+
+    for x0 in a {
+      let x = x0.getPrintable()
+      x.printme()
+      // OUTPUT: SomeCStruct: 1, 2
+      // OUTPUT: SomeCEnum: .caseA
+      // OUTPUT: SomeNSEnum: .someCaseB
+    }
+  }
+}