[embedded] Require whole module optimization in embedded mode.

Author: zoecarver

include/swift/AST/DiagnosticsFrontend.def

@@ -556,6 +556,8 @@ ERROR(layout_string_instantiation_without_layout_strings,none,
 
 ERROR(evolution_with_embedded,none,
       "Library evolution cannot be enabled with embedded Swift.", ())
+ERROR(wmo_with_embedded,none,
+      "Whole module optimization (wmo) must be enabled with embedded Swift.", ())
 
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

lib/Frontend/CompilerInvocation.cpp

@@ -1340,6 +1340,15 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     }
   }
 
+  // Is this the correct way to query for WMO?
+  bool isWMO =
+    Args.hasArg(OPT_wmo) ||
+    Args.hasArg(OPT_whole_module_optimization);
+  if (!isWMO && Opts.hasFeature(Feature::Embedded)) {
+    Diags.diagnose(SourceLoc(), diag::wmo_with_embedded);
+    HadError = true;
+  }
+
   return HadError || UnsupportedOS || UnsupportedArch;
 }
 

test/embedded/basic-errors-no-stdlib.swift

@@ -1,4 +1,4 @@
-// RUN: not %target-swift-frontend -emit-ir %s -parse-stdlib -enable-experimental-feature Embedded 2>&1 | %FileCheck %s
+// RUN: not %target-swift-frontend -emit-ir %s -parse-stdlib -enable-experimental-feature Embedded -wmo 2>&1 | %FileCheck %s
 
 public protocol Player {}
 struct Concrete: Player {}

test/embedded/basic-irgen-no-stdlib.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-emit-ir %s -parse-stdlib -enable-experimental-feature Embedded -target arm64e-apple-none | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -parse-stdlib -enable-experimental-feature Embedded -target arm64e-apple-none -wmo | %FileCheck %s
 
 // TODO: investigate why windows is generating more metadata.
 // XFAIL: OS=windows-msvc

test/embedded/evolution-with-embedded-diag.swift

@@ -1,4 +1,4 @@
-// RUN: not %target-swift-frontend -emit-ir %s -enable-library-evolution -enable-experimental-feature Embedded 2>&1 | %FileCheck %s
-// RUN: not %target-swift-frontend -emit-ir %s -enable-resilience -enable-experimental-feature Embedded 2>&1 | %FileCheck %s
+// RUN: not %target-swift-frontend -emit-ir %s -enable-library-evolution -enable-experimental-feature Embedded -wmo 2>&1 | %FileCheck %s
+// RUN: not %target-swift-frontend -emit-ir %s -enable-resilience -enable-experimental-feature Embedded -wmo 2>&1 | %FileCheck %s
 
 // CHECK: error: Library evolution cannot be enabled with embedded Swift.

test/embedded/wmo-with-embedded-diag.swift

@@ -0,0 +1,3 @@
+// RUN: not %target-swift-frontend -emit-ir %s -enable-experimental-feature Embedded 2>&1 | %FileCheck %s
+
+// CHECK: error: Whole module optimization (wmo) must be enabled with embedded Swift.