Driver: diagnose options that are only supported in the new driver

include/swift/AST/DiagnosticsDriver.def

@@ -173,5 +173,7 @@ WARNING(warn_drv_darwin_sdk_invalid_settings, none,
     "SDK settings were ignored because 'SDKSettings.json' could not be parsed",
     ())
 
+WARNING(warning_unsupported_driver_option,none,
+        "option '%0' is ony supported in swift-driver", (StringRef))
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

include/swift/Option/Options.h

@@ -40,6 +40,7 @@ namespace options {
     SwiftAPIExtractOption = (1 << 15),
     SwiftSymbolGraphExtractOption = (1 << 16),
     SwiftAPIDigesterOption = (1 << 17),
+    NewDriverOnlyOption = (1 << 18),
   };
 
   enum ID {

include/swift/Option/Options.td

@@ -64,6 +64,9 @@ def SwiftSymbolGraphExtractOption : OptionFlag;
 // The option should be accepted by swift-api-digester.
 def SwiftAPIDigesterOption : OptionFlag;
 
+// The option only functions in the new driver.
+def NewDriverOnlyOption : OptionFlag;
+
 /////////
 // Options
 
@@ -1181,7 +1184,7 @@ def working_directory_EQ : Joined<["-"], "working-directory=">,
   Alias<working_directory>;
 
 def user_module_version : Separate<["-"], "user-module-version">,
-  Flags<[FrontendOption, ModuleInterfaceOption]>,
+  Flags<[FrontendOption, ModuleInterfaceOption, NewDriverOnlyOption]>,
   HelpText<"Module version specified from Swift module authors">,
   MetaVarName<"<vers>">;
 

test/Driver/diagnose-new-driver-flags.swift

@@ -0,0 +1,3 @@
+// RUN: %swiftc_driver -emit-module -user-module-version 999.999 %s -### 2>&1 | %FileCheck %s
+
+// CHECK: warning: option '-user-module-version' is ony supported in swift-driver

tools/driver/driver.cpp

@@ -276,6 +276,13 @@ static int run_driver(StringRef ExecName,
   if (Diags.hadAnyError())
     return 1;
 
+  for (auto arg: ArgList->getArgs()) {
+    if (arg->getOption().hasFlag(options::NewDriverOnlyOption)) {
+      Diags.diagnose(SourceLoc(), diag::warning_unsupported_driver_option,
+                     arg->getSpelling());
+    }
+  }
+
   std::unique_ptr<Compilation> C =
       TheDriver.buildCompilation(*TC, std::move(ArgList));