Merge pull request #38465 from nkcsgexi/80703470-5.5

[5.5]ModuleInterface: pass down -disable-availability-checking to module building command

Author: tkremenek

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -1182,6 +1182,10 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
   // If we are supposed to use RequireOSSAModules, do so.
   genericSubInvocation.getSILOptions().EnableOSSAModules =
       bool(RequireOSSAModules);
+  if (LangOpts.DisableAvailabilityChecking) {
+    genericSubInvocation.getLangOptions().DisableAvailabilityChecking = true;
+    GenericArgs.push_back("-disable-availability-checking");
+  }
 }
 
 bool InterfaceSubContextDelegateImpl::extractSwiftInterfaceVersionAndArgs(

test/ModuleInterface/disable-availability-checking.swift

@@ -0,0 +1,16 @@
+// REQUIRES: OS=macosx && CPU=x86_64
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/inputs)
+// RUN: %empty-directory(%t/modulecache)
+// RUN: echo "// swift-interface-format-version: 1.0" > %t/inputs/Foo.swiftinterface
+// RUN: echo "// swift-module-flags: -module-name Foo" >> %t/inputs/Foo.swiftinterface
+// RUN: echo "@available(macOS 11, *)" >> %t/inputs/Foo.swiftinterface
+// RUN: echo "public class Foo {}" >> %t/inputs/Foo.swiftinterface
+// RUN: echo "public extension Foo { public func f() {} }" >> %t/inputs/Foo.swiftinterface
+
+// RUN: not %target-swift-frontend -emit-module-path %t/Bar.swiftmodule -enable-library-evolution -enable-objc-interop -disable-objc-attr-requires-foundation-module -module-name Bar %s -I %t/inputs -target x86_64-apple-macos10.9 -module-cache-path %t/modulecache
+
+// RUN: %target-swift-frontend -emit-module-path %t/Bar.swiftmodule -enable-library-evolution -enable-objc-interop -disable-objc-attr-requires-foundation-module -module-name Bar %s -I %t/inputs -target x86_64-apple-macos10.9 -disable-availability-checking -module-cache-path %t/modulecache
+
+import Foo
+