Merge pull request #38610 from CodaFi/pile-driver

[5.5] Eat -experimental-emit-module-separately

Author: CodaFi

include/swift/Option/Options.td

@@ -579,6 +579,10 @@ def experimental_cxx_stdlib :
   Separate<["-"], "experimental-cxx-stdlib">,
   HelpText<"C++ standard library to use; forwarded to Clang's -stdlib flag">;
 
+def experimental_emit_module_separately:
+  Flag<["-"], "experimental-emit-module-separately">,
+  Flags<[FrontendOption, NoInteractiveOption, HelpHidden]>,
+  HelpText<"Schedule a swift module emission job instead of a merge-modules job (new Driver only)">;
 
 // Diagnostic control options
 def suppress_warnings : Flag<["-"], "suppress-warnings">,

test/Driver/emit_module_separately.swift

@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+// RUN: touch %t/file1.swift %t/file2.swift %t/file3.swift
+// RUN: echo 'public func main() {}' >%t/main.swift
+//
+// RUN: %target-swiftc_driver -driver-skip-execution -c -emit-module -module-name main -driver-print-jobs %s -experimental-emit-module-separately %t/file1.swift %t/file2.swift %t/file3.swift %t/main.swift 2>^1 | %FileCheck -check-prefix NORMAL %s
+// RUN: %target-swiftc_driver -driver-skip-execution -c -emit-module -module-name main -driver-print-jobs -incremental %s -experimental-emit-module-separately %t/file1.swift %t/file2.swift %t/file3.swift %t/main.swift 2>^1 | %FileCheck -check-prefix INCREMENTAL %s
+
+// Just test that we eat this argument. Only the new driver knows what to do
+// here. The legacy driver will just fall back to a merge-modules job as usual.
+// NORMAL: swift
+// NORMAL-NOT: -experimental-emit-module-separately
+
+// INCREMENTAL: swift
+// INCREMENTAL: -merge-modules
+// INCREMENTAL-NOT: -experimental-emit-module-separately