Reflection: Fix metadata for empty cases

Also change std::endl to '\n' in the dumper, since std::endl flushes
the output stream.

Author: slavapestov

include/swift/Reflection/Records.h

@@ -52,6 +52,11 @@ class FieldRecord {
 
 public:
   FieldRecord() = delete;
+
+  bool hasMangledTypeName() const {
+    return MangledTypeName;
+  }
+
   std::string getMangledTypeName() const {
     return MangledTypeName.get();
   }

include/swift/Reflection/ReflectionContext.h

@@ -206,16 +206,16 @@ class ReflectionContext
   void dumpTypeRef(const std::string &MangledName,
                    std::ostream &OS, bool printTypeName = false) {
     auto TypeName = Demangle::demangleTypeAsString(MangledName);
-    OS << TypeName << std::endl;
+    OS << TypeName << '\n';
 
     auto DemangleTree = Demangle::demangleTypeAsNode(MangledName);
     auto TR = decodeMangledType(DemangleTree);
     if (!TR) {
-      OS << "!!! Invalid typeref: " << MangledName << std::endl;
+      OS << "!!! Invalid typeref: " << MangledName << '\n';
       return;
     }
     TR->dump(OS);
-    OS << std::endl;
+    OS << '\n';
   }
 
   const AssociatedTypeDescriptor *
@@ -259,13 +259,18 @@ class ReflectionContext
       for (const auto &descriptor : sections.fieldmd) {
         auto TypeName
           = Demangle::demangleTypeAsString(descriptor.getMangledTypeName());
-        OS << TypeName << std::endl;
+        OS << TypeName << '\n';
         for (size_t i = 0; i < TypeName.size(); ++i)
           OS << '-';
-        OS << std::endl;
+        OS << '\n';
         for (auto &field : descriptor) {
-          OS << field.getFieldName() << ": ";
-          dumpTypeRef(field.getMangledTypeName(), OS);
+          OS << field.getFieldName();
+          if (field.hasMangledTypeName()) {
+            OS << ": ";
+            dumpTypeRef(field.getMangledTypeName(), OS);
+          } else {
+            OS << "\n\n";
+          }
         }
       }
     }
@@ -280,7 +285,7 @@ class ReflectionContext
           descriptor.getMangledProtocolTypeName());
 
         OS << conformingTypeName << " : " << protocolName;
-        OS << std::endl;
+        OS << '\n';
 
         for (const auto &associatedType : descriptor) {
           OS << "typealias " << associatedType.getName() << " = ";
@@ -291,15 +296,15 @@ class ReflectionContext
   }
 
   void dumpAllSections(std::ostream &OS) {
-    OS << "FIELDS:" << std::endl;
+    OS << "FIELDS:\n";
     for (size_t i = 0; i < 7; ++i) OS << '=';
-    OS << std::endl;
+    OS << '\n';
     dumpFieldSection(OS);
-    OS << "\nASSOCIATED TYPES:" << std::endl;
+    OS << "\nASSOCIATED TYPES:\n";
     for (size_t i = 0; i < 17; ++i) OS << '=';
-    OS << std::endl;
+    OS << '\n';
     dumpAssociatedTypeSection(OS);
-    OS << std::endl;
+    OS << '\n';
   }
 
   TypeRef *
@@ -340,13 +345,21 @@ class ReflectionContext
         if (MangledName.compare(CandidateMangledName) != 0)
           continue;
         for (auto &Field : FieldDescriptor) {
+          auto FieldName = Field.getFieldName();
+
+          // Empty cases of enums do not have a type
+          if (!Field.hasMangledTypeName()) {
+            Fields.push_back({FieldName, nullptr});
+            continue;
+          }
+
           auto Demangled
-          = Demangle::demangleTypeAsNode(Field.getMangledTypeName());
+            = Demangle::demangleTypeAsNode(Field.getMangledTypeName());
           auto Unsubstituted = decodeMangledType(Demangled);
           if (!Unsubstituted)
             return {};
+
           auto Substituted = Unsubstituted->subst(*this, Subs);
-          auto FieldName = Field.getFieldName();
           if (FieldName.empty())
             FieldName = "<Redacted Field Name>";
           Fields.push_back({FieldName, Substituted});

lib/IRGen/GenReflection.cpp

@@ -132,7 +132,11 @@ class FieldTypeMetadataBuilder : public ReflectionMetadataBuilder {
 
     addConstantInt32(Flags.getRawValue());
 
-    addTypeRef(value->getModuleContext(), type);
+    if (!type) {
+      addConstantInt32(0);
+    } else {
+      addTypeRef(value->getModuleContext(), type);
+    }
 
     if (IGM.Opts.StripReflectionNames) {
       addConstantInt32(0);
@@ -164,10 +168,15 @@ class FieldTypeMetadataBuilder : public ReflectionMetadataBuilder {
       auto cases = enumDecl->getAllElements();
       addConstantInt32(std::distance(cases.begin(), cases.end()));
       addConstantInt32(fieldRecordSize);
-      for (auto enumCase : cases)
-        addFieldDecl(enumCase,
-                     enumCase->getArgumentInterfaceType()
-                       ->getCanonicalType());
+      for (auto enumCase : cases) {
+        if (enumCase->hasArgumentType()) {
+          addFieldDecl(enumCase,
+                       enumCase->getArgumentInterfaceType()
+                         ->getCanonicalType());
+        } else {
+          addFieldDecl(enumCase, CanType());
+        }
+      }
       break;
     }
     default:

test/Reflection/Inputs/ConcreteTypes.swift

@@ -52,6 +52,7 @@ public enum E {
   indirect case IndirectTuple(C, S, E, Int)
   case Metatype(E.Type)
   case NestedStruct(S.NestedS)
+  case EmptyCase
 }
 
 public struct References {

test/Reflection/typeref_decoding.result.txt

@@ -127,6 +127,8 @@ NestedStruct: TypesToReflect.S.NestedS
 (struct TypesToReflect.S.NestedS
   (struct TypesToReflect.S))
 
+EmptyCase
+
 TypesToReflect.References
 -------------------------
 strongRef: TypesToReflect.C

test/Reflection/typeref_decoding_objc.result.txt

@@ -127,6 +127,8 @@ NestedStruct: TypesToReflect.S.NestedS
 (struct TypesToReflect.S.NestedS
   (struct TypesToReflect.S))
 
+EmptyCase
+
 TypesToReflect.References
 -------------------------
 strongRef: TypesToReflect.C