[embedded][ptrauth] Guard extra ptrauth verification on objc interop being enabled.

This verification runs on ObjC briging types which are not present in embedded stdlib or when objc interop is not enabled.

Author: zoecarver

lib/IRGen/IRGenModule.cpp

@@ -196,6 +196,8 @@ static void sanityCheckStdlib(IRGenModule &IGM) {
   // Only run the sanity check when we're building the real stdlib.
   if (!lookupSimple(IGM.getSwiftModule(), { "String" })) return;
 
+  if (!IGM.ObjCInterop) return;
+
   checkPointerAuthAssociatedTypeDiscriminator(IGM, { "_ObjectiveCBridgeable", "_ObjectiveCType" }, SpecialPointerAuthDiscriminators::ObjectiveCTypeDiscriminator);
   checkPointerAuthWitnessDiscriminator(IGM, { "_ObjectiveCBridgeable", "_bridgeToObjectiveC" }, SpecialPointerAuthDiscriminators::bridgeToObjectiveCDiscriminator);
   checkPointerAuthWitnessDiscriminator(IGM, { "_ObjectiveCBridgeable", "_forceBridgeFromObjectiveC" }, SpecialPointerAuthDiscriminators::forceBridgeFromObjectiveCDiscriminator);

test/embedded/ptr-auth-irgen-verify-no-stdlib.swift

@@ -0,0 +1,11 @@
+// RUN: %target-swift-emit-ir %s -parse-stdlib -enable-experimental-feature Embedded -target arm64e-apple-none -Xcc -fptrauth-calls -module-name Swift | %FileCheck %s
+
+// Windows does not have SwiftCompilerSources.
+// XFAIL: OS=windows-msvc
+
+// Some verification is blocked on string lookup succeeding.
+struct String {}
+
+public func test() { }
+
+// CHECK-LABEL: define {{.*}}void @"$ss4testyyF"()