TF-587: Default arguments not working in Swift-Jupyter (#25664)

Revert "IRGen: give non_abi WeakODR linkage"

This reverts commit 846a64b.

Author: marcrasi

lib/IRGen/GenDecl.cpp

@@ -1654,16 +1654,13 @@ getIRLinkage(const UniversalLinkageInfo &info, SILLinkage linkage,
     return {llvm::GlobalValue::ExternalLinkage, PublicDefinitionVisibility,
             ExportedStorage};
 
-  case SILLinkage::PublicNonABI:
-    return isDefinition ? RESULT(WeakODR, Hidden, Default)
-                        : RESULT(External, Hidden, Default);
-
   case SILLinkage::Shared:
   case SILLinkage::SharedExternal:
     return isDefinition ? RESULT(LinkOnceODR, Hidden, Default)
                         : RESULT(External, Hidden, Default);
 
   case SILLinkage::Hidden:
+  case SILLinkage::PublicNonABI:
     return RESULT(External, Hidden, Default);
 
   case SILLinkage::Private: {

test/IRGen/sil_linkage.sil

@@ -5,7 +5,7 @@ sil_stage canonical
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @public_fragile_function_test() {{.*}} {
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @public_transparent_fragile_function_test() {{.*}} {
 // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @public_transparent_function_test() {{.*}} {
-// CHECK: define weak_odr hidden swiftcc void @public_non_abi_function_test() {{.*}} {
+// CHECK: define hidden swiftcc void @public_non_abi_function_test() {{.*}} {
 // CHECK: define hidden swiftcc void @hidden_fragile_function_test() {{.*}} {
 // CHECK: define linkonce_odr hidden swiftcc void @shared_fragile_function_test() {{.*}} {
 // CHECK: define{{( internal)?}} swiftcc void @private_fragile_function_test() {{.*}} {