NFC: refactor applyObjCProtocolQualifiers from SemaType.cpp to ASTContext so it can be shared.

[manmanren]

Summary

To construct the canonical type of ObjCTypeParamType, we need to apply qualifiers on ObjCObjectPointerType. The updated applyObjCProtocolQualifiers handles this case by merging the protocol lists, constructing a new ObjCObjectType, then a new ObjCObjectPointerType.

[doug.gregor]

Yep, this refactor looks good!

include/clang/AST/ASTContext.h

public:
   /// \brief Return the uniqued reference to the type for an address space
   /// qualified type with the specified type and address space.
   ///
   /// The resulting type has a union of the qualifiers from T and the address
   /// space. If T already has an address space specifier, it is silently
   /// replaced.
   QualType getAddrSpaceQualType(QualType T, unsigned AddressSpace) const;
 
+  /// \brief Apply Objective-C protocol qualifiers to the given type.
+  /// \param allowOnPointerType specifies if we can apply protocol
+  /// qualifiers on ObjCObjectPointerType. It can be set to true when
+  /// contructing the canonical type of a Objective-C type parameter.
+  QualType applyObjCProtocolQualifiers(QualType type,
+      ArrayRef<ObjCProtocolDecl *> protocols, bool &hasError,
+      bool allowOnPointerType = false) const;
+
   /// \brief Return the uniqued reference to the type for an Objective-C
   /// gc-qualified type.
   ///
   /// The retulting type has a union of the qualifiers from T and the gc
   /// attribute.
   QualType getObjCGCQualType(QualType T, Qualifiers::GC gcAttr) const;
 
   /// \brief Return the uniqued reference to the type for a \c restrict

lib/AST/ASTContext.cpp

ObjCObjectTypeImpl *T =
     new (mem) ObjCObjectTypeImpl(canonical, baseType, typeArgs, protocols,
                                  isKindOf);
 
   Types.push_back(T);
   ObjCObjectTypes.InsertNode(T, InsertPos);
   return QualType(T, 0);
 }
 
+/// Apply Objective-C protocol qualifiers to the given type.
+/// If this is for the canonical type of a type parameter, we can apply
+/// protocol qualifiers on the ObjCObjectPointerType.
+QualType
+ASTContext::applyObjCProtocolQualifiers(QualType type,
+                  ArrayRef<ObjCProtocolDecl *> protocols, bool &hasError,
+                  bool allowOnPointerType) const {
+  hasError = false;
+
+  // Apply protocol qualifiers to ObjCObjectPointerType.
+  if (allowOnPointerType) {
+    if (const ObjCObjectPointerType *objPtr =
+        dyn_cast<ObjCObjectPointerType>(type.getTypePtr())) {
+      const ObjCObjectType *objT = objPtr->getObjectType();
+      // Merge protocol lists and construct ObjCObjectType.
+      SmallVector<ObjCProtocolDecl*, 8> protocolsVec;
+      protocolsVec.append(objT->qual_begin(),
+                          objT->qual_end());
+      protocolsVec.append(protocols.begin(), protocols.end());
+      ArrayRef<ObjCProtocolDecl *> protocols = protocolsVec;
+      type = getObjCObjectType(
+             objT->getBaseType(),
+             objT->getTypeArgsAsWritten(),
+             protocols,
+             objT->isKindOfTypeAsWritten());
+      return getObjCObjectPointerType(type);
+    }
+  }
+
+  // Apply protocol qualifiers to ObjCObjectType.
+  if (const ObjCObjectType *objT = dyn_cast<ObjCObjectType>(type.getTypePtr())){
+    // FIXME: Check for protocols to which the class type is already
+    // known to conform.
+
+    return getObjCObjectType(objT->getBaseType(),
+                             objT->getTypeArgsAsWritten(),
+                             protocols,
+                             objT->isKindOfTypeAsWritten());
+  }
+
+  // If the canonical type is ObjCObjectType, ...
+  if (type->isObjCObjectType()) {
+    // Silently overwrite any existing protocol qualifiers.
+    // TODO: determine whether that's the right thing to do.
+
+    // FIXME: Check for protocols to which the class type is already
+    // known to conform.
+    return getObjCObjectType(type, { }, protocols, false);
+  }
+
+  // id<protocol-list>
+  if (type->isObjCIdType()) {
+    const ObjCObjectPointerType *objPtr = type->castAs<ObjCObjectPointerType>();
+    type = getObjCObjectType(ObjCBuiltinIdTy, { }, protocols,
+                                 objPtr->isKindOfType());
+    return getObjCObjectPointerType(type);
+  }
+
+  // Class<protocol-list>
+  if (type->isObjCClassType()) {
+    const ObjCObjectPointerType *objPtr = type->castAs<ObjCObjectPointerType>();
+    type = getObjCObjectType(ObjCBuiltinClassTy, { }, protocols,
+                                 objPtr->isKindOfType());
+    return getObjCObjectPointerType(type);
+  }
+
+  hasError = true;
+  return type;
+}
+
 /// ObjCObjectAdoptsQTypeProtocols - Checks that protocols in IC's
 /// protocol list adopt all protocols in QT's qualified-id protocol
 /// list.
 bool ASTContext::ObjCObjectAdoptsQTypeProtocols(QualType QT,
                                                 ObjCInterfaceDecl *IC) {
   if (!QT->isObjCQualifiedIdType())
     return false;
   

lib/Sema/SemaType.cpp

if (!anyPackExpansions && finalTypeArgs.size() != numTypeParams) {
 
     return type;
   }
 
   // Success. Form the specialized type.
   return S.Context.getObjCObjectType(type, finalTypeArgs, { }, false);
 }
 
-/// Apply Objective-C protocol qualifiers to the given type.
-static QualType applyObjCProtocolQualifiers(
-                  Sema &S, SourceLocation loc, SourceRange range, QualType type,
-                  ArrayRef<ObjCProtocolDecl *> protocols,
-                  const SourceLocation *protocolLocs,
-                  bool failOnError = false) {
-  ASTContext &ctx = S.Context;
-  if (const ObjCObjectType *objT = dyn_cast<ObjCObjectType>(type.getTypePtr())){
-    // FIXME: Check for protocols to which the class type is already
-    // known to conform.
-
-    return ctx.getObjCObjectType(objT->getBaseType(),
-                                 objT->getTypeArgsAsWritten(),
-                                 protocols,
-                                 objT->isKindOfTypeAsWritten());
-  }
-
-  if (type->isObjCObjectType()) {
-    // Silently overwrite any existing protocol qualifiers.
-    // TODO: determine whether that's the right thing to do.
-
-    // FIXME: Check for protocols to which the class type is already
-    // known to conform.
-    return ctx.getObjCObjectType(type, { }, protocols, false);
-  }
-
-  // id<protocol-list>
-  if (type->isObjCIdType()) {
-    const ObjCObjectPointerType *objPtr = type->castAs<ObjCObjectPointerType>();
-    type = ctx.getObjCObjectType(ctx.ObjCBuiltinIdTy, { }, protocols,
-                                 objPtr->isKindOfType());
-    return ctx.getObjCObjectPointerType(type);
-  }
-
-  // Class<protocol-list>
-  if (type->isObjCClassType()) {
-    const ObjCObjectPointerType *objPtr = type->castAs<ObjCObjectPointerType>();
-    type = ctx.getObjCObjectType(ctx.ObjCBuiltinClassTy, { }, protocols,
-                                 objPtr->isKindOfType());
-    return ctx.getObjCObjectPointerType(type);
-  }
-
-  S.Diag(loc, diag::err_invalid_protocol_qualifiers)
-    << range;
-
-  if (failOnError)
-    return QualType();
-
-  return type;
-}
-
 QualType Sema::BuildObjCObjectType(QualType BaseType,
                                    SourceLocation Loc,
                                    SourceLocation TypeArgsLAngleLoc,
                                    ArrayRef<TypeSourceInfo *> TypeArgs,
                                    SourceLocation TypeArgsRAngleLoc,
                                    SourceLocation ProtocolLAngleLoc,
                                    ArrayRef<ObjCProtocolDecl *> Protocols,
                                    ArrayRef<SourceLocation> ProtocolLocs,
                                    SourceLocation ProtocolRAngleLoc,
                                    bool FailOnError) {
   QualType Result = BaseType;
   if (!TypeArgs.empty()) {
     Result = applyObjCTypeArgs(*this, Loc, Result, TypeArgs,
                                SourceRange(TypeArgsLAngleLoc,
                                            TypeArgsRAngleLoc),
                                FailOnError);
     if (FailOnError && Result.isNull())
       return QualType();
   }
 
   if (!Protocols.empty()) {
-    Result = applyObjCProtocolQualifiers(*this, Loc,
-                                         SourceRange(ProtocolLAngleLoc,
-                                                     ProtocolRAngleLoc),
-                                         Result, Protocols,
-                                         ProtocolLocs.data(),
-                                         FailOnError);
+    bool HasError;
+    Result = Context.applyObjCProtocolQualifiers(Result, Protocols,
+                                                 HasError);
+    if (HasError) {
+      Diag(Loc, diag::err_invalid_protocol_qualifiers)
+        << SourceRange(ProtocolLAngleLoc, ProtocolRAngleLoc);
+      if (FailOnError) Result = QualType();
+    }
     if (FailOnError && Result.isNull())
       return QualType();
   }
 
   return Result;
 }
 
 TypeResult Sema::actOnObjCProtocolQualifierType(