disable CMO when compiling swiftmodule files

Summary: Disable CMO when compiling swiftmodules in a separate action. This is required to compile correctly, otherwise we end up with swiftmodule inlining issues that fail at link time.

Reviewed By: milend

Differential Revision: D62244498

fbshipit-source-id: 3d667f686c0354486b0d2b49d75f3e86c67e37de

prelude/apple/swift/swift_compilation.bzl

@@ -352,7 +352,9 @@ def _compile_swiftmodule(
         swift_framework_output: SwiftLibraryForDistributionOutput | None) -> CompileArgsfiles:
     argfile_cmd = cmd_args(shared_flags)
     argfile_cmd.add([
+        "-disable-cmo",
         "-emit-module",
+        "-experimental-emit-module-separately",
     ])
 
     if ctx.attrs.swift_module_skip_function_bodies: