Revert back to previous ns_Error_enum behavior

(cherry picked from commit 759ba98)

Author: hyp

clang/include/clang/Basic/Attr.td

@@ -2056,7 +2056,7 @@ def ObjCBridgeRelated : InheritableAttr {
 def NSErrorDomain : InheritableAttr {
   let Spellings = [GNU<"ns_error_domain">];
   let Subjects = SubjectList<[Enum], ErrorDiag>;
-  let Args = [DeclArgument<Var, "ErrorDomain">];
+  let Args = [IdentifierArgument<"ErrorDomain">];
   let Documentation = [NSErrorDomainDocs];
 }
 

clang/lib/Sema/SemaAPINotes.cpp

@@ -347,22 +347,11 @@ static void ProcessAPINotes(Sema &S, Decl *D,
 
   // ns_error_domain
   if (auto nsErrorDomain = info.getNSErrorDomain()) {
-    handleAPINotedAttribute<NSErrorDomainAttr>(
-        S, D, !nsErrorDomain->empty(), metadata, [&]() -> NSErrorDomainAttr * {
-          LookupResult lookupResult(
-              S, DeclarationName(&S.Context.Idents.get(*nsErrorDomain)),
-              SourceLocation(), Sema::LookupNameKind::LookupOrdinaryName);
-          S.LookupName(lookupResult, S.TUScope);
-          auto *VD = lookupResult.getAsSingle<VarDecl>();
-
-          if (!VD) {
-            S.Diag(D->getLocation(), diag::err_nserrordomain_invalid_decl) << 0;
-            return nullptr;
-          }
-
-          return new (S.Context)
-              NSErrorDomainAttr(S.Context, getDummyAttrInfo(), VD);
-        });
+    handleAPINotedAttribute<NSErrorDomainAttr>(S, D, !nsErrorDomain->empty(),
+                                               metadata, [&] {
+      return new (S.Context) NSErrorDomainAttr(
+          S.Context, getDummyAttrInfo(), &S.Context.Idents.get(*nsErrorDomain));
+    });
   }
 
   ProcessAPINotes(S, D, static_cast<const api_notes::CommonEntityInfo &>(info),

clang/lib/Sema/SemaDeclAttr.cpp

@@ -5656,29 +5656,37 @@ static void handleObjCRequiresSuperAttr(Sema &S, Decl *D,
   D->addAttr(::new (S.Context) ObjCRequiresSuperAttr(S.Context, Attrs));
 }
 
-static void handleNSErrorDomain(Sema &S, Decl *D, const ParsedAttr &AL) {
-  auto *E = AL.getArgAsExpr(0);
-  auto Loc = E ? E->getBeginLoc() : AL.getLoc();
-
-  auto *DRE = dyn_cast<DeclRefExpr>(AL.getArgAsExpr(0));
-  if (!DRE) {
-    S.Diag(Loc, diag::err_nserrordomain_invalid_decl) << 0;
+static void handleNSErrorDomain(Sema &S, Decl *D, const ParsedAttr &Attr) {
+  if (!isa<TagDecl>(D)) {
+    S.Diag(D->getBeginLoc(), diag::err_nserrordomain_invalid_decl)
+        << 0;
     return;
   }
+  IdentifierLoc *identLoc =
+      Attr.isArgIdent(0) ? Attr.getArgAsIdent(0) : nullptr;
+  if (!identLoc || !identLoc->Ident) {
+    // Try to locate the argument directly
+    SourceLocation loc = Attr.getLoc();
+    if (Attr.isArgExpr(0) && Attr.getArgAsExpr(0))
+      loc = Attr.getArgAsExpr(0)->getBeginLoc();
 
-  auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
-  if (!VD) {
-    S.Diag(Loc, diag::err_nserrordomain_invalid_decl) << 1 << DRE->getDecl();
+    S.Diag(loc, diag::err_nserrordomain_invalid_decl) << 0;
     return;
   }
 
-  if (!isNSStringType(VD->getType(), S.Context) &&
-      !isCFStringType(VD->getType(), S.Context)) {
-    S.Diag(Loc, diag::err_nserrordomain_wrong_type) << VD;
+  // Verify that the identifier is a valid decl in the C decl namespace
+  LookupResult lookupResult(S, DeclarationName(identLoc->Ident),
+                            SourceLocation(),
+                            Sema::LookupNameKind::LookupOrdinaryName);
+  if (!S.LookupName(lookupResult, S.TUScope) ||
+      !lookupResult.getAsSingle<VarDecl>()) {
+    S.Diag(identLoc->Loc, diag::err_nserrordomain_invalid_decl)
+        << 1 << identLoc->Ident;
     return;
   }
 
-  D->addAttr(::new (S.Context) NSErrorDomainAttr(S.Context, AL, VD));
+  D->addAttr(::new (S.Context)
+                 NSErrorDomainAttr(S.Context, Attr, identLoc->Ident));
 }
 
 static void handleObjCBridgeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {

clang/test/Sema/ns_error_enum.m

@@ -53,7 +53,6 @@ typedef NS_ERROR_ENUM(unsigned char, MyCFTypedefErrorEnum, MyCFTypedefErrorDomai
 
 extern char *const WrongErrorDomainType;
 enum __attribute__((ns_error_domain(WrongErrorDomainType))) MyWrongErrorDomainType { MyWrongErrorDomain };
-// expected-error@-1{{domain argument 'WrongErrorDomainType' does not point to an NSString or CFString constant}}
 
 struct __attribute__((ns_error_domain(MyErrorDomain))) MyStructWithErrorDomain {};
 // expected-error@-1{{'ns_error_domain' attribute only applies to enums}}
@@ -68,7 +67,7 @@ typedef NS_ERROR_ENUM(unsigned char, MyCFTypedefErrorEnum, MyCFTypedefErrorDomai
 // expected-error@-1{{'ns_error_domain' attribute takes one argument}}
 
 typedef NS_ERROR_ENUM(unsigned char, MyErrorEnumInvalid, InvalidDomain) {
-	// expected-error@-1{{use of undeclared identifier 'InvalidDomain'}}
+	// expected-error@-1{{domain argument 'InvalidDomain' does not refer to global constant}}
 	MyErrFirstInvalid,
 	MyErrSecondInvalid,
 };