Modify DeclaratorChuck::getFunction to use DeclSpec for qualifiers

[Anastasia]

Summary

Rather than duplicating data fields, use DeclSpec directly to store qualifiers for the functions/methods.

This change is discussed in the following comment:
https://reviews.llvm.org/D55850#inline-495037

[rjmccall]

include/clang/Sema/DeclSpec.h

1316

Can we give this a better name? I know we use "type qualifiers" for this concept in the AST, but it's not a good name, and we should really rename it in the AST. How about MethodQualifiers?

lib/Parse/ParseDecl.cpp

6126

Is it possible to just build into a local DS and then move that DS to the heap if it contains qualifiers or attributes? It'd be nice to not do a heap allocation every time we parse a function declarator in C++ since the vast majority of them don't have qualifiers. (It probably has to be a move to handle attributes and AttributeFactory correctly.)

That would also side-step any concerns about memory management.

[Anastasia]

• Changed to store DeclSpec only when quals are present.
• Renamed to MethodQualifiers.

[Anastasia]

lib/Parse/ParseDecl.cpp

6126

I found DeclSpec a bit copy-unfriednly... not sure it was better to modify its interface. For now I just provide custom impl for function quals.

[rjmccall]

include/clang/Sema/DeclSpec.h

1381

This DeclSpec ends up with a dangling reference to the AttributeFactory; I think you need to allocate them both when used.

Consider having this return a DeclSpec & and making it the primary way that clients get a mutable DS.

1422–1423

The "if any" suggests that that this method (and below) can be called on a DS that doesn't have this qualifier. If that's not actually true, you should assert that MethodQualifiers exists and change the comment.

1462

It might be reasonable to just remove these accessors and make more things query the DS if it exists.

1605

Spacing

lib/Parse/ParseDeclCXX.cpp

2351–2352

Since you're touching this code anyway, please make this an early return (before the declaration of Insertion) and de-indent the rest of the helper.

2352

Either MethodQualifiers already exists (because it has the qualifier) or you'll be creating it (to add the qualifier); might as well force it to exist eagerly and simplify the logic here and below.

2363–2364

Please remove this dead semicolon since you're touching this code anyway.

lib/Sema/DeclSpec.cpp

175

Consider taking this as a pointer just so that the various places that construct one of these when method qualifiers are impossible don't have to construct a DS unnecessarily.

lib/Sema/SemaDeclCXX.cpp

8360–8365

Should there be a method on DS that iterates over the type qualifiers present? You could have it take an llvm::function_ref<void(TQ, StringRef, SourceLoc)> or something.

[Anastasia]

Addressed review comments.

[Anastasia]

lib/Parse/ParseDeclCXX.cpp

2363–2364

Here the semicolon is at the end of a lambda declaration statement.

[rjmccall]

lib/Parse/ParseDeclCXX.cpp

2363–2364

Oh, yes it is, sorry.

lib/Parse/ParseExprCXX.cpp

1264

This is dead now.

lib/Sema/DeclSpec.cpp

233

Spacing?

lib/Sema/SemaDeclCXX.cpp

8175–8180

I think you should add a hasMethodQualifiers method to FTI that does this check. Note that it needs to check for attributes, too, and I think you need to figure out some way to generalize forEachCVRUQual to cover those.

8181

I'd write this lambda inline as the argument, but if you think it's better separate, that's okay.

8360–8365

Another place for hasMethodQualifiers.

lib/Sema/SemaType.cpp

719

This is dead now.

4459

This would be a good place to use hasMethodQualifiers (unless there's a reason to ignore attribute qualifiers here).

5032

A lambda this simple should definitely be written inline.

[Anastasia]

lib/Sema/DeclSpec.cpp

233

I am keeping the old formatting from the lines 195-204. But obviously it doesn't match with the current clang-format rules. Do you prefer that I reformat the whole block or just this line?

lib/Sema/SemaDeclCXX.cpp

8175–8180

Are there any attributes I should handle currently?

Also are you suggesting to add another forEach... method or extend existing? If the latter, I might not be able to use it in all places I use it now.

[rjmccall]

lib/Sema/DeclSpec.cpp

233

Oh, I see. Could you hoist the null-initialization of these two fields above this block, then? They'll look more consistent, and it'll make it clearer that you're establishing the basic invariants on these fields before modifying them.

lib/Sema/SemaDeclCXX.cpp

8175–8180

Adding another method might be easier. How many clients actually use the TQ?

[Anastasia]

lib/Sema/SemaDeclCXX.cpp

8175–8180

In DeclSpec.cpp I definitely need just TQ. I am not sure about SemaType.cpp. All other places (3x) I guess should be possible to generalize. Although I am not very clear if I should be checking all attr. It might be a bit exhaustive since the use cases are for the function?

Perhaps, I could add an extra helper forEachQualifier that can call forEachCVRUQual and then I could add a FIXME to complete the rest. We can extend it as we discover what's missing. For example I will add address spaces there in my next patch. Would this make sense?

As for hasMethodQualifiers just to be clear I would need to check for all qualifiers including reference qualifier, attributes, etc?

[rjmccall]

lib/Sema/SemaDeclCXX.cpp

8175–8180

That seems like a reasonable short-term plan. Maybe there needs to be some way to describe an individual qualifier; we can hash that out in a separate patch.

As for hasMethodQualifiers just to be clear I would need to check for all qualifiers including reference qualifier, attributes, etc?

Maybe, although at least one of the cases below wants to check for ref-qualifiers separately. Maybe it should be hasMethodTypeQualifiers, and it implies that MethodQualifiers->forEachQualifier will invoke the callback at least once.

[Anastasia]

• Added forEachQualifiers to DeclSpec.
• Removed dead code.
• Moved lambdas definition inline into the function parameters.

lib/Sema/SemaDeclCXX.cpp

8175–8180

I think it should be sufficient to check that MethodQualifiers exist because we only create it if we have either a type qual or any attribute.

[rjmccall]

lib/Sema/SemaDeclCXX.cpp

8175–8180

Hmm. I think we can remove qualifiers, and we do sometimes (at least in recovery situations, and possibly in others), so it's better not to rely on that. But I think for attributes you can just check whether there are any attributes rather than carefully checking whether any attribute is a type qualifier.

[Anastasia]

Added hasMethodTypeQualifiers method.

[rjmccall]

Thanks! LGTM.

include/clang/Sema/DeclSpec.h

void ClearFunctionSpecs() {
     FS_virtual_specified = false;
     FS_virtualLoc = SourceLocation();
     FS_explicit_specified = false;
     FS_explicitLoc = SourceLocation();
     FS_noreturn_specified = false;
     FS_noreturnLoc = SourceLocation();
   }
 
+  /// This method calls the passed in handler on each CVRU qual being
+  /// set.
+  /// Handle - a handler to be invoked.
+  void forEachCVRUQualifier(
+      llvm::function_ref<void(TQ, StringRef, SourceLocation)> Handle);
+
+  /// This method calls the passed in handler on each qual being
+  /// set.
+  /// Handle - a handler to be invoked.
+  void forEachQualifier(
+      llvm::function_ref<void(TQ, StringRef, SourceLocation)> Handle);
+
   /// Return true if any type-specifier has been found.
   bool hasTypeSpecifier() const {
     return getTypeSpecType() != DeclSpec::TST_unspecified ||
            getTypeSpecWidth() != DeclSpec::TSW_unspecified ||
            getTypeSpecComplex() != DeclSpec::TSC_unspecified ||
            getTypeSpecSign() != DeclSpec::TSS_unspecified;
   }
 
void UpdateTypeRep(ParsedType Rep) {
     assert(isTypeRep((TST) TypeSpecType));
     TypeRep = Rep;
   }
   void UpdateExprRep(Expr *Rep) {
     assert(isExprRep((TST) TypeSpecType));
     ExprRep = Rep;
   }
 
+  bool SetTypeQual(TQ T, SourceLocation Loc);
+
   bool SetTypeQual(TQ T, SourceLocation Loc, const char *&PrevSpec,
                    unsigned &DiagID, const LangOptions &Lang);
 
   bool setFunctionSpecInline(SourceLocation Loc, const char *&PrevSpec,
                              unsigned &DiagID);
   bool setFunctionSpecForceInline(SourceLocation Loc, const char *&PrevSpec,
                                   unsigned &DiagID);
   bool setFunctionSpecVirtual(SourceLocation Loc, const char *&PrevSpec,
struct FunctionTypeInfo {
 
     /// Can this declaration be a constructor-style initializer?
     unsigned isAmbiguous : 1;
 
     /// Whether the ref-qualifier (if any) is an lvalue reference.
     /// Otherwise, it's an rvalue reference.
     unsigned RefQualifierIsLValueRef : 1;
 
-    /// The type qualifiers: const/volatile/restrict/__unaligned
-    /// The qualifier bitmask values are the same as in QualType.
-    unsigned TypeQuals : 4;
-
     /// ExceptionSpecType - An ExceptionSpecificationType value.
     unsigned ExceptionSpecType : 4;
 
     /// DeleteParams - If this is true, we need to delete[] Params.
     unsigned DeleteParams : 1;
 
     /// HasTrailingReturnType - If this is true, a trailing return type was
     /// specified.
struct FunctionTypeInfo {
     /// number of declarations in the function prototype.
     unsigned NumExceptionsOrDecls;
 
     /// The location of the ref-qualifier, if any.
     ///
     /// If this is an invalid location, there is no ref-qualifier.
     unsigned RefQualifierLoc;
 
-    /// The location of the const-qualifier, if any.
-    ///
-    /// If this is an invalid location, there is no const-qualifier.
-    unsigned ConstQualifierLoc;
-
-    /// The location of the volatile-qualifier, if any.
-    ///
-    /// If this is an invalid location, there is no volatile-qualifier.
-    unsigned VolatileQualifierLoc;
-
-    /// The location of the restrict-qualifier, if any.
-    ///
-    /// If this is an invalid location, there is no restrict-qualifier.
-    unsigned RestrictQualifierLoc;
-
     /// The location of the 'mutable' qualifer in a lambda-declarator, if
     /// any.
     unsigned MutableLoc;
 
     /// The beginning location of the exception specification, if any.
     unsigned ExceptionSpecLocBeg;
 
     /// The end location of the exception specification, if any.
     unsigned ExceptionSpecLocEnd;
 
     /// Params - This is a pointer to a new[]'d array of ParamInfo objects that
     /// describe the parameters specified by this function declarator.  null if
     /// there are no parameters specified.
     ParamInfo *Params;
 
+    /// DeclSpec for the function with the qualifier related info.
+    DeclSpec *MethodQualifiers;
+
+    /// AtttibuteFactory for the MethodQualifiers.
+    AttributeFactory *QualAttrFactory;
+
     union {
       /// Pointer to a new[]'d array of TypeAndRange objects that
       /// contain the types in the function's dynamic exception specification
       /// and their locations, if there is one.
       TypeAndRange *Exceptions;
 
       /// Pointer to the expression in the noexcept-specifier of this
       /// function, if it has one.
void freeParams() {
         delete[] Params;
         DeleteParams = false;
       }
       NumParams = 0;
     }
 
     void destroy() {
       freeParams();
+      delete QualAttrFactory;
+      delete MethodQualifiers;
       switch (getExceptionSpecType()) {
       default:
         break;
       case EST_Dynamic:
         delete[] Exceptions;
         break;
       case EST_Unparsed:
         delete ExceptionSpecTokens;
         break;
       case EST_None:
         if (NumExceptionsOrDecls != 0)
           delete[] DeclsInPrototype;
         break;
       }
     }
 
+    DeclSpec &getOrCreateMethodQualifiers() {
+      if (!MethodQualifiers) {
+        QualAttrFactory = new AttributeFactory();
+        MethodQualifiers = new DeclSpec(*QualAttrFactory);
+      }
+      return *MethodQualifiers;
+    }
+
     /// isKNRPrototype - Return true if this is a K&R style identifier list,
     /// like "void foo(a,b,c)".  In a function definition, this will be followed
     /// by the parameter type definitions.
     bool isKNRPrototype() const { return !hasPrototype && NumParams != 0; }
 
     SourceLocation getLParenLoc() const {
       return SourceLocation::getFromRawEncoding(LParenLoc);
     }
SourceRange getExceptionSpecRange() const {
       return SourceRange(getExceptionSpecLocBeg(), getExceptionSpecLocEnd());
     }
 
     /// Retrieve the location of the ref-qualifier, if any.
     SourceLocation getRefQualifierLoc() const {
       return SourceLocation::getFromRawEncoding(RefQualifierLoc);
     }
 
-    /// Retrieve the location of the 'const' qualifier, if any.
+    /// Retrieve the location of the 'const' qualifier.
     SourceLocation getConstQualifierLoc() const {
-      return SourceLocation::getFromRawEncoding(ConstQualifierLoc);
+      assert(MethodQualifiers);
+      return MethodQualifiers->getConstSpecLoc();
     }
 
-    /// Retrieve the location of the 'volatile' qualifier, if any.
+    /// Retrieve the location of the 'volatile' qualifier.
     SourceLocation getVolatileQualifierLoc() const {
-      return SourceLocation::getFromRawEncoding(VolatileQualifierLoc);
+      assert(MethodQualifiers);
+      return MethodQualifiers->getVolatileSpecLoc();
     }
 
-    /// Retrieve the location of the 'restrict' qualifier, if any.
+    /// Retrieve the location of the 'restrict' qualifier.
     SourceLocation getRestrictQualifierLoc() const {
-      return SourceLocation::getFromRawEncoding(RestrictQualifierLoc);
+      assert(MethodQualifiers);
+      return MethodQualifiers->getRestrictSpecLoc();
     }
 
     /// Retrieve the location of the 'mutable' qualifier, if any.
     SourceLocation getMutableLoc() const {
       return SourceLocation::getFromRawEncoding(MutableLoc);
     }
 
     /// Determine whether this function declaration contains a
struct FunctionTypeInfo {
     }
 
     /// Get the number of dynamic exception specifications.
     unsigned getNumExceptions() const {
       assert(ExceptionSpecType != EST_None);
       return NumExceptionsOrDecls;
     }
 
     /// Get the non-parameter decls defined within this function
     /// prototype. Typically these are tag declarations.
     ArrayRef<NamedDecl *> getDeclsInPrototype() const {
       assert(ExceptionSpecType == EST_None);
       return llvm::makeArrayRef(DeclsInPrototype, NumExceptionsOrDecls);
     }
 
     /// Determine whether this function declarator had a
     /// trailing-return-type.
struct DeclaratorChunk {
   /// DeclaratorChunk::getFunction - Return a DeclaratorChunk for a function.
   /// "TheDeclarator" is the declarator that this will be added to.
   static DeclaratorChunk getFunction(bool HasProto,
                                      bool IsAmbiguous,
                                      SourceLocation LParenLoc,
                                      ParamInfo *Params, unsigned NumParams,
                                      SourceLocation EllipsisLoc,
                                      SourceLocation RParenLoc,
-                                     unsigned TypeQuals,
                                      bool RefQualifierIsLvalueRef,
                                      SourceLocation RefQualifierLoc,
-                                     SourceLocation ConstQualifierLoc,
-                                     SourceLocation VolatileQualifierLoc,
-                                     SourceLocation RestrictQualifierLoc,
                                      SourceLocation MutableLoc,
                                      ExceptionSpecificationType ESpecType,
                                      SourceRange ESpecRange,
                                      ParsedType *Exceptions,
                                      SourceRange *ExceptionRanges,
                                      unsigned NumExceptions,
                                      Expr *NoexceptExpr,
                                      CachedTokens *ExceptionSpecTokens,
                                      ArrayRef<NamedDecl *> DeclsInPrototype,
                                      SourceLocation LocalRangeBegin,
                                      SourceLocation LocalRangeEnd,
                                      Declarator &TheDeclarator,
                                      TypeResult TrailingReturnType =
-                                                    TypeResult());
+                                                    TypeResult(),
+                                     DeclSpec *MethodQualifiers = nullptr);
 
   /// Return a DeclaratorChunk for a block.
   static DeclaratorChunk getBlockPointer(unsigned TypeQuals,
                                          SourceLocation Loc) {
     DeclaratorChunk I;
     I.Kind          = BlockPointer;
     I.Loc           = Loc;
     I.Cls.TypeQuals = TypeQuals;

lib/Parse/ParseDecl.cpp

void Parser::ParseFunctionDeclarator(Declarator &D,
   // Build up an array of information about the parsed arguments.
   SmallVector<DeclaratorChunk::ParamInfo, 16> ParamInfo;
   // Remember where we see an ellipsis, if any.
   SourceLocation EllipsisLoc;
 
   DeclSpec DS(AttrFactory);
   bool RefQualifierIsLValueRef = true;
   SourceLocation RefQualifierLoc;
-  SourceLocation ConstQualifierLoc;
-  SourceLocation VolatileQualifierLoc;
-  SourceLocation RestrictQualifierLoc;
   ExceptionSpecificationType ESpecType = EST_None;
   SourceRange ESpecRange;
   SmallVector<ParsedType, 2> DynamicExceptions;
   SmallVector<SourceRange, 2> DynamicExceptionRanges;
   ExprResult NoexceptExpr;
   CachedTokens *ExceptionSpecTokens = nullptr;
   ParsedAttributesWithRange FnAttrs(AttrFactory);
   TypeResult TrailingReturnType;
if (isFunctionDeclaratorIdentifierList()) {
     Tracker.consumeClose();
     RParenLoc = Tracker.getCloseLocation();
     LocalEndLoc = RParenLoc;
     EndLoc = RParenLoc;
 
     if (getLangOpts().CPlusPlus) {
       // FIXME: Accept these components in any order, and produce fixits to
       // correct the order if the user gets it wrong. Ideally we should deal
       // with the pure-specifier in the same way.
 
       // Parse cv-qualifier-seq[opt].
       ParseTypeQualifierListOpt(DS, AR_NoAttributesParsed,
                                 /*AtomicAllowed*/ false,
                                 /*IdentifierRequired=*/false,
                                 llvm::function_ref<void()>([&]() {
                                   Actions.CodeCompleteFunctionQualifiers(DS, D);
                                 }));
       if (!DS.getSourceRange().getEnd().isInvalid()) {
         EndLoc = DS.getSourceRange().getEnd();
-        ConstQualifierLoc = DS.getConstSpecLoc();
-        VolatileQualifierLoc = DS.getVolatileSpecLoc();
-        RestrictQualifierLoc = DS.getRestrictSpecLoc();
       }
 
       // Parse ref-qualifier[opt].
       if (ParseRefQualifier(RefQualifierIsLValueRef, RefQualifierLoc))
         EndLoc = RefQualifierLoc;
 
       // C++11 [expr.prim.general]p3:
       //   If a declaration declares a member function or member function
for (Decl *D : getCurScope()->decls()) {
       DeclsInPrototype.push_back(ND);
     }
   }
 
   // Remember that we parsed a function type, and remember the attributes.
   D.AddTypeInfo(DeclaratorChunk::getFunction(
                     HasProto, IsAmbiguous, LParenLoc, ParamInfo.data(),
                     ParamInfo.size(), EllipsisLoc, RParenLoc,
-                    DS.getTypeQualifiers(), RefQualifierIsLValueRef,
-                    RefQualifierLoc, ConstQualifierLoc, VolatileQualifierLoc,
-                    RestrictQualifierLoc,
-                    /*MutableLoc=*/SourceLocation(), ESpecType, ESpecRange,
-                    DynamicExceptions.data(), DynamicExceptionRanges.data(),
-                    DynamicExceptions.size(),
+                    RefQualifierIsLValueRef, RefQualifierLoc,
+                    /*MutableLoc=*/SourceLocation(),
+                    ESpecType, ESpecRange, DynamicExceptions.data(),
+                    DynamicExceptionRanges.data(), DynamicExceptions.size(),
                     NoexceptExpr.isUsable() ? NoexceptExpr.get() : nullptr,
                     ExceptionSpecTokens, DeclsInPrototype, StartLoc,
-                    LocalEndLoc, D, TrailingReturnType),
+                    LocalEndLoc, D, TrailingReturnType, &DS),
                 std::move(FnAttrs), EndLoc);
 }
 
 /// ParseRefQualifier - Parses a member function ref-qualifier. Returns
 /// true if a ref-qualifier is found.
 bool Parser::ParseRefQualifier(bool &RefQualifierIsLValueRef,
                                SourceLocation &RefQualifierLoc) {
   if (Tok.isOneOf(tok::amp, tok::ampamp)) {

lib/Parse/ParseDeclCXX.cpp

ParseTypeQualifierListOpt(
       /*IdentifierRequired=*/false, llvm::function_ref<void()>([&]() {
         Actions.CodeCompleteFunctionQualifiers(DS, D, &VS);
       }));
   D.ExtendWithDeclSpec(DS);
 
   if (D.isFunctionDeclarator()) {
     auto &Function = D.getFunctionTypeInfo();
     if (DS.getTypeQualifiers() != DeclSpec::TQ_unspecified) {
-      auto DeclSpecCheck = [&] (DeclSpec::TQ TypeQual,
-                                const char *FixItName,
-                                SourceLocation SpecLoc,
-                                unsigned* QualifierLoc) {
+      auto DeclSpecCheck = [&](DeclSpec::TQ TypeQual, StringRef FixItName,
+                               SourceLocation SpecLoc) {
         FixItHint Insertion;
-        if (DS.getTypeQualifiers() & TypeQual) {
-          if (!(Function.TypeQuals & TypeQual)) {
-            std::string Name(FixItName);
-            Name += " ";
-            Insertion = FixItHint::CreateInsertion(VS.getFirstLocation(), Name);
-            Function.TypeQuals |= TypeQual;
-            *QualifierLoc = SpecLoc.getRawEncoding();
-          }
-          Diag(SpecLoc, diag::err_declspec_after_virtspec)
+        auto &MQ = Function.getOrCreateMethodQualifiers();
+        if (!(MQ.getTypeQualifiers() & TypeQual)) {
+          std::string Name(FixItName.data());
+          MQ.SetTypeQual(TypeQual, SpecLoc);
             << FixItName
             << VirtSpecifiers::getSpecifierName(VS.getLastSpecifier())
-            << FixItHint::CreateRemoval(SpecLoc)
-            << Insertion;
-        }
+            << FixItHint::CreateRemoval(SpecLoc) << Insertion;
       };
-      DeclSpecCheck(DeclSpec::TQ_const, "const", DS.getConstSpecLoc(),
-                    &Function.ConstQualifierLoc);
-      DeclSpecCheck(DeclSpec::TQ_volatile, "volatile", DS.getVolatileSpecLoc(),
-                    &Function.VolatileQualifierLoc);
-      DeclSpecCheck(DeclSpec::TQ_restrict, "restrict", DS.getRestrictSpecLoc(),
-                    &Function.RestrictQualifierLoc);
+      DS.forEachQualifier(DeclSpecCheck);
     }
 
     // Parse ref-qualifiers.
     bool RefQualifierIsLValueRef = true;
     SourceLocation RefQualifierLoc;
     if (ParseRefQualifier(RefQualifierIsLValueRef, RefQualifierLoc)) {
       const char *Name = (RefQualifierIsLValueRef ? "& " : "&& ");
       FixItHint Insertion = FixItHint::CreateInsertion(VS.getFirstLocation(), Name);

lib/Parse/ParseExpr.cpp

if (Tok.is(tok::l_paren)) {
     ParamInfo.AddTypeInfo(
         DeclaratorChunk::getFunction(/*HasProto=*/true,
                                      /*IsAmbiguous=*/false,
                                      /*RParenLoc=*/NoLoc,
                                      /*ArgInfo=*/nullptr,
                                      /*NumArgs=*/0,
                                      /*EllipsisLoc=*/NoLoc,
                                      /*RParenLoc=*/NoLoc,
-                                     /*TypeQuals=*/0,
                                      /*RefQualifierIsLvalueRef=*/true,
                                      /*RefQualifierLoc=*/NoLoc,
-                                     /*ConstQualifierLoc=*/NoLoc,
-                                     /*VolatileQualifierLoc=*/NoLoc,
-                                     /*RestrictQualifierLoc=*/NoLoc,
                                      /*MutableLoc=*/NoLoc, EST_None,
                                      /*ESpecRange=*/SourceRange(),
                                      /*Exceptions=*/nullptr,
                                      /*ExceptionRanges=*/nullptr,
                                      /*NumExceptions=*/0,
                                      /*NoexceptExpr=*/nullptr,
                                      /*ExceptionSpecTokens=*/nullptr,
                                      /*DeclsInPrototype=*/None, CaretLoc,

lib/Parse/ParseExprCXX.cpp

if (Tok.is(tok::l_paren)) {
 
     WarnIfHasCUDATargetAttr();
 
     SourceLocation NoLoc;
     D.AddTypeInfo(DeclaratorChunk::getFunction(
                       /*hasProto=*/true,
                       /*isAmbiguous=*/false, LParenLoc, ParamInfo.data(),
                       ParamInfo.size(), EllipsisLoc, RParenLoc,
-                      DS.getTypeQualifiers(),
                       /*RefQualifierIsLValueRef=*/true,
-                      /*RefQualifierLoc=*/NoLoc,
-                      /*ConstQualifierLoc=*/NoLoc,
-                      /*VolatileQualifierLoc=*/NoLoc,
-                      /*RestrictQualifierLoc=*/NoLoc, MutableLoc, ESpecType,
+                      /*RefQualifierLoc=*/NoLoc, MutableLoc, ESpecType,
                       ESpecRange, DynamicExceptions.data(),
                       DynamicExceptionRanges.data(), DynamicExceptions.size(),
                       NoexceptExpr.isUsable() ? NoexceptExpr.get() : nullptr,
                       /*ExceptionSpecTokens*/ nullptr,
                       /*DeclsInPrototype=*/None, LParenLoc, FunLocalRangeEnd, D,
                       TrailingReturnType),
                   std::move(Attr), DeclEndLoc);
   } else if (Tok.isOneOf(tok::kw_mutable, tok::arrow, tok::kw___attribute,
if (Tok.is(tok::arrow)) {
           ParseTrailingReturnType(Range, /*MayBeFollowedByDirectInit*/ false);
       if (Range.getEnd().isValid())
         DeclEndLoc = Range.getEnd();
     }
 
     WarnIfHasCUDATargetAttr();
 
     SourceLocation NoLoc;
     D.AddTypeInfo(DeclaratorChunk::getFunction(
                       /*hasProto=*/true,
                       /*isAmbiguous=*/false,
                       /*LParenLoc=*/NoLoc,
                       /*Params=*/nullptr,
                       /*NumParams=*/0,
                       /*EllipsisLoc=*/NoLoc,
                       /*RParenLoc=*/NoLoc,
-                      /*TypeQuals=*/0,
                       /*RefQualifierIsLValueRef=*/true,
-                      /*RefQualifierLoc=*/NoLoc,
-                      /*ConstQualifierLoc=*/NoLoc,
-                      /*VolatileQualifierLoc=*/NoLoc,
-                      /*RestrictQualifierLoc=*/NoLoc, MutableLoc, EST_None,
+                      /*RefQualifierLoc=*/NoLoc, MutableLoc, EST_None,
                       /*ESpecRange=*/SourceRange(),
                       /*Exceptions=*/nullptr,
                       /*ExceptionRanges=*/nullptr,
                       /*NumExceptions=*/0,
                       /*NoexceptExpr=*/nullptr,
                       /*ExceptionSpecTokens=*/nullptr,
                       /*DeclsInPrototype=*/None, DeclLoc, DeclEndLoc, D,
                       TrailingReturnType),

lib/Sema/DeclSpec.cpp

 /// "TheDeclarator" is the declarator that this will be added to.
 DeclaratorChunk DeclaratorChunk::getFunction(bool hasProto,
                                              bool isAmbiguous,
                                              SourceLocation LParenLoc,
                                              ParamInfo *Params,
                                              unsigned NumParams,
                                              SourceLocation EllipsisLoc,
                                              SourceLocation RParenLoc,
-                                             unsigned TypeQuals,
                                              bool RefQualifierIsLvalueRef,
                                              SourceLocation RefQualifierLoc,
-                                             SourceLocation ConstQualifierLoc,
-                                             SourceLocation
-                                                 VolatileQualifierLoc,
-                                             SourceLocation
-                                                 RestrictQualifierLoc,
                                              SourceLocation MutableLoc,
                                              ExceptionSpecificationType
                                                  ESpecType,
                                              SourceRange ESpecRange,
                                              ParsedType *Exceptions,
                                              SourceRange *ExceptionRanges,
                                              unsigned NumExceptions,
                                              Expr *NoexceptExpr,
                                              CachedTokens *ExceptionSpecTokens,
                                              ArrayRef<NamedDecl*>
                                                  DeclsInPrototype,
                                              SourceLocation LocalRangeBegin,
                                              SourceLocation LocalRangeEnd,
                                              Declarator &TheDeclarator,
-                                             TypeResult TrailingReturnType) {
-  assert(!(TypeQuals & DeclSpec::TQ_atomic) &&
+                                             TypeResult TrailingReturnType,
+                                             DeclSpec *MethodQualifiers) {
+  assert(!(MethodQualifiers && MethodQualifiers->getTypeQualifiers() & DeclSpec::TQ_atomic) &&
          "function cannot have _Atomic qualifier");
 
   DeclaratorChunk I;
   I.Kind                        = Function;
   I.Loc                         = LocalRangeBegin;
   I.EndLoc                      = LocalRangeEnd;
   I.Fun.hasPrototype            = hasProto;
   I.Fun.isVariadic              = EllipsisLoc.isValid();
   I.Fun.isAmbiguous             = isAmbiguous;
   I.Fun.LParenLoc               = LParenLoc.getRawEncoding();
   I.Fun.EllipsisLoc             = EllipsisLoc.getRawEncoding();
   I.Fun.RParenLoc               = RParenLoc.getRawEncoding();
   I.Fun.DeleteParams            = false;
-  I.Fun.TypeQuals               = TypeQuals;
   I.Fun.NumParams               = NumParams;
   I.Fun.Params                  = nullptr;
   I.Fun.RefQualifierIsLValueRef = RefQualifierIsLvalueRef;
   I.Fun.RefQualifierLoc         = RefQualifierLoc.getRawEncoding();
-  I.Fun.ConstQualifierLoc       = ConstQualifierLoc.getRawEncoding();
-  I.Fun.VolatileQualifierLoc    = VolatileQualifierLoc.getRawEncoding();
-  I.Fun.RestrictQualifierLoc    = RestrictQualifierLoc.getRawEncoding();
   I.Fun.MutableLoc              = MutableLoc.getRawEncoding();
   I.Fun.ExceptionSpecType       = ESpecType;
   I.Fun.ExceptionSpecLocBeg     = ESpecRange.getBegin().getRawEncoding();
   I.Fun.ExceptionSpecLocEnd     = ESpecRange.getEnd().getRawEncoding();
   I.Fun.NumExceptionsOrDecls    = 0;
   I.Fun.Exceptions              = nullptr;
   I.Fun.NoexceptExpr            = nullptr;
   I.Fun.HasTrailingReturnType   = TrailingReturnType.isUsable() ||
                                   TrailingReturnType.isInvalid();
   I.Fun.TrailingReturnType      = TrailingReturnType.get();
+  I.Fun.MethodQualifiers        = nullptr;
+  I.Fun.QualAttrFactory         = nullptr;
+
+  if (MethodQualifiers && (MethodQualifiers->getTypeQualifiers() ||
+                           MethodQualifiers->getAttributes().size())) {
+    auto &attrs = MethodQualifiers->getAttributes();
+    I.Fun.MethodQualifiers = new DeclSpec(attrs.getPool().getFactory());
+    MethodQualifiers->forEachCVRUQualifier(
+        [&](DeclSpec::TQ TypeQual, StringRef PrintName, SourceLocation SL) {
+          I.Fun.MethodQualifiers->SetTypeQual(TypeQual, SL);
+        });
+    I.Fun.MethodQualifiers->getAttributes().takeAllFrom(attrs);
+    I.Fun.MethodQualifiers->getAttributePool().takeAllFrom(attrs.getPool());
+  }
 
-  assert(I.Fun.TypeQuals == TypeQuals && "bitfield overflow");
   assert(I.Fun.ExceptionSpecType == ESpecType && "bitfield overflow");
 
   // new[] a parameter array if needed.
   if (NumParams) {
     // If the 'InlineParams' in Declarator is unused and big enough, put our
     // parameter list there (in an effort to avoid new/delete traffic).  If it
     // is already used (consider a function returning a function pointer) or too
     // small (function with too many parameters), go to the heap.
     if (!TheDeclarator.InlineStorageUsed &&
         NumParams <= llvm::array_lengthof(TheDeclarator.InlineParams)) {
       I.Fun.Params = TheDeclarator.InlineParams;
       new (I.Fun.Params) ParamInfo[NumParams];
       I.Fun.DeleteParams = false;
       TheDeclarator.InlineStorageUsed = true;
     } else {
       I.Fun.Params = new DeclaratorChunk::ParamInfo[NumParams];
       I.Fun.DeleteParams = true;
     }
     for (unsigned i = 0; i < NumParams; i++)
       I.Fun.Params[i] = std::move(Params[i]);
   }
 
return getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_static ||
               getName().OperatorFunctionId.Operator));
 }
 
 bool Declarator::isCtorOrDtor() {
   return (getName().getKind() == UnqualifiedIdKind::IK_ConstructorName) ||
          (getName().getKind() == UnqualifiedIdKind::IK_DestructorName);
 }
 
+void DeclSpec::forEachCVRUQualifier(
+    llvm::function_ref<void(TQ, StringRef, SourceLocation)> Handle) {
+  if (TypeQualifiers & TQ_const)
+    Handle(TQ_const, "const", TQ_constLoc);
+  if (TypeQualifiers & TQ_volatile)
+    Handle(TQ_volatile, "volatile", TQ_volatileLoc);
+  if (TypeQualifiers & TQ_restrict)
+    Handle(TQ_restrict, "restrict", TQ_restrictLoc);
+  if (TypeQualifiers & TQ_unaligned)
+    Handle(TQ_unaligned, "unaligned", TQ_unalignedLoc);
+}
+
+void DeclSpec::forEachQualifier(
+    llvm::function_ref<void(TQ, StringRef, SourceLocation)> Handle) {
+  forEachCVRUQualifier(Handle);
+  // FIXME: Add code below to iterate through the attributes and call Handle.
+}
+
 bool DeclSpec::hasTagDefinition() const {
   if (!TypeSpecOwned)
     return false;
   return cast<TagDecl>(getRepAsDecl())->isCompleteDefinition();
 }
 
 /// getParsedSpecifiers - Return a bitmask of which flavors of specifiers this
 /// declaration specifier includes.
bool DeclSpec::SetTypeQual(TQ T, SourceLocation Loc, const char *&PrevSpec,
   // always warn.  We do not need to set the qualifier's location since we
   // already have it.
   if (TypeQualifiers & T) {
     bool IsExtension = true;
     if (Lang.C99)
       IsExtension = false;
     return BadSpecifier(T, T, PrevSpec, DiagID, IsExtension);
   }
+
+  return SetTypeQual(T, Loc);
+}
+
+bool DeclSpec::SetTypeQual(TQ T, SourceLocation Loc) {
   TypeQualifiers |= T;
 
   switch (T) {
   case TQ_unspecified: break;
   case TQ_const:    TQ_constLoc = Loc; return false;
   case TQ_restrict: TQ_restrictLoc = Loc; return false;
   case TQ_volatile: TQ_volatileLoc = Loc; return false;
   case TQ_unaligned: TQ_unalignedLoc = Loc; return false;

lib/Sema/SemaDecl.cpp

NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
   Declarator D(DS, DeclaratorContext::BlockContext);
   D.AddTypeInfo(DeclaratorChunk::getFunction(/*HasProto=*/false,
                                              /*IsAmbiguous=*/false,
                                              /*LParenLoc=*/NoLoc,
                                              /*Params=*/nullptr,
                                              /*NumParams=*/0,
                                              /*EllipsisLoc=*/NoLoc,
                                              /*RParenLoc=*/NoLoc,
-                                             /*TypeQuals=*/0,
                                              /*RefQualifierIsLvalueRef=*/true,
                                              /*RefQualifierLoc=*/NoLoc,
-                                             /*ConstQualifierLoc=*/NoLoc,
-                                             /*VolatileQualifierLoc=*/NoLoc,
-                                             /*RestrictQualifierLoc=*/NoLoc,
                                              /*MutableLoc=*/NoLoc, EST_None,
                                              /*ESpecRange=*/SourceRange(),
                                              /*Exceptions=*/nullptr,
                                              /*ExceptionRanges=*/nullptr,
                                              /*NumExceptions=*/0,
                                              /*NoexceptExpr=*/nullptr,
                                              /*ExceptionSpecTokens=*/nullptr,
                                              /*DeclsInPrototype=*/None, Loc,

lib/Sema/SemaDeclCXX.cpp

diagnoseIgnoredQualifiers(
         diag::err_constructor_return_type, TypeQuals, SourceLocation(),
         D.getDeclSpec().getConstSpecLoc(), D.getDeclSpec().getVolatileSpecLoc(),
         D.getDeclSpec().getRestrictSpecLoc(),
         D.getDeclSpec().getAtomicSpecLoc());
     D.setInvalidType();
   }
 
   DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
-  if (FTI.TypeQuals != 0) {
-    if (FTI.TypeQuals & Qualifiers::Const)
-      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_constructor)
-        << "const" << SourceRange(D.getIdentifierLoc());
-    if (FTI.TypeQuals & Qualifiers::Volatile)
-      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_constructor)
-        << "volatile" << SourceRange(D.getIdentifierLoc());
-    if (FTI.TypeQuals & Qualifiers::Restrict)
-      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_constructor)
-        << "restrict" << SourceRange(D.getIdentifierLoc());
+  if (FTI.MethodQualifiers) {
+    FTI.MethodQualifiers->forEachQualifier(
+        [&](DeclSpec::TQ TypeQual, StringRef QualName, SourceLocation SL) {
+          Diag(SL, diag::err_invalid_qualified_constructor)
+              << QualName << SourceRange(SL);
+        });
     D.setInvalidType();
   }
 
   // C++0x [class.ctor]p4:
   //   A constructor shall not be declared with a ref-qualifier.
   if (FTI.hasRefQualifier()) {
     Diag(FTI.getRefQualifierLoc(), diag::err_ref_qualifier_constructor)
       << FTI.RefQualifierIsLValueRef
       << FixItHint::CreateRemoval(FTI.getRefQualifierLoc());
else if (unsigned TypeQuals = D.getDeclSpec().getTypeQualifiers()) {
                                 D.getDeclSpec().getVolatileSpecLoc(),
                                 D.getDeclSpec().getRestrictSpecLoc(),
                                 D.getDeclSpec().getAtomicSpecLoc());
       D.setInvalidType();
     }
   }
 
   DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();
-  if (FTI.TypeQuals != 0 && !D.isInvalidType()) {
-    if (FTI.TypeQuals & Qualifiers::Const)
-      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_destructor)
-        << "const" << SourceRange(D.getIdentifierLoc());
-    if (FTI.TypeQuals & Qualifiers::Volatile)
-      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_destructor)
-        << "volatile" << SourceRange(D.getIdentifierLoc());
-    if (FTI.TypeQuals & Qualifiers::Restrict)
-      Diag(D.getIdentifierLoc(), diag::err_invalid_qualified_destructor)
-        << "restrict" << SourceRange(D.getIdentifierLoc());
+  if (FTI.MethodQualifiers && !D.isInvalidType()) {
+    FTI.MethodQualifiers->forEachQualifier(
+        [&](DeclSpec::TQ TypeQual, StringRef QualName, SourceLocation SL) {
+          Diag(SL, diag::err_invalid_qualified_destructor)
+              << QualName << SourceRange(SL);
+        });
     D.setInvalidType();
   }
 
   // C++0x [class.dtor]p2:
   //   A destructor shall not be declared with a ref-qualifier.
   if (FTI.hasRefQualifier()) {
     Diag(FTI.getRefQualifierLoc(), diag::err_ref_qualifier_destructor)
       << FTI.RefQualifierIsLValueRef

lib/Sema/SemaLambda.cpp

if (ParamInfo.getNumTypeObjects() == 0) {
     assert(ParamInfo.isFunctionDeclarator() &&
            "lambda-declarator is a function");
     DeclaratorChunk::FunctionTypeInfo &FTI = ParamInfo.getFunctionTypeInfo();
 
     // C++11 [expr.prim.lambda]p5:
     //   This function call operator is declared const (9.3.1) if and only if
     //   the lambda-expression's parameter-declaration-clause is not followed
     //   by mutable. It is neither virtual nor declared volatile. [...]
-    if (!FTI.hasMutableQualifier())
-      FTI.TypeQuals |= DeclSpec::TQ_const;
+    if (!FTI.hasMutableQualifier()) {
+      FTI.getOrCreateMethodQualifiers().SetTypeQual(DeclSpec::TQ_const,
+                                                    SourceLocation());
+    }
 
     MethodTyInfo = GetTypeForDeclarator(ParamInfo, CurScope);
     assert(MethodTyInfo && "no type from lambda-declarator");
     EndLoc = ParamInfo.getSourceRange().getEnd();
 
     ExplicitResultType = FTI.hasTrailingReturnType();
 
     if (FTIHasNonVoidParameters(FTI)) {

lib/Sema/SemaType.cpp

static void maybeSynthesizeBlockSignature(TypeProcessingState &state,
   // occur only in failed efforts to make function declarators, so
   // faking up the function chunk is still the right thing to do.
 
   // Otherwise, we need to fake up a function declarator.
   SourceLocation loc = declarator.getBeginLoc();
 
   // ...and *prepend* it to the declarator.
   SourceLocation NoLoc;
   declarator.AddInnermostTypeInfo(DeclaratorChunk::getFunction(
       /*HasProto=*/true,
       /*IsAmbiguous=*/false,
       /*LParenLoc=*/NoLoc,
       /*ArgInfo=*/nullptr,
       /*NumArgs=*/0,
       /*EllipsisLoc=*/NoLoc,
       /*RParenLoc=*/NoLoc,
-      /*TypeQuals=*/0,
       /*RefQualifierIsLvalueRef=*/true,
       /*RefQualifierLoc=*/NoLoc,
-      /*ConstQualifierLoc=*/NoLoc,
-      /*VolatileQualifierLoc=*/NoLoc,
-      /*RestrictQualifierLoc=*/NoLoc,
       /*MutableLoc=*/NoLoc, EST_None,
       /*ESpecRange=*/SourceRange(),
       /*Exceptions=*/nullptr,
       /*ExceptionRanges=*/nullptr,
       /*NumExceptions=*/0,
       /*NoexceptExpr=*/nullptr,
       /*ExceptionSpecTokens=*/nullptr,
-      /*DeclsInPrototype=*/None,
-      loc, loc, declarator));
+      /*DeclsInPrototype=*/None, loc, loc, declarator));
 
   // For consistency, make sure the state still has us as processing
   // the decl spec.
   assert(state.getCurrentChunkIndex() == declarator.getNumTypeObjects() - 1);
   state.setCurrentChunkIndex(declarator.getNumTypeObjects());
 }
 
 static void diagnoseAndRemoveTypeQualifiers(Sema &S, const DeclSpec &DS,
case DeclaratorChunk::Array: {
                            SourceRange(DeclType.Loc, DeclType.EndLoc), Name);
       break;
     }
     case DeclaratorChunk::Function: {
       // If the function declarator has a prototype (i.e. it is not () and
       // does not have a K&R-style identifier list), then the arguments are part
       // of the type, otherwise the argument list is ().
       const DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
-      IsQualifiedFunction = FTI.TypeQuals || FTI.hasRefQualifier();
+      IsQualifiedFunction = FTI.MethodQualifiers || FTI.hasRefQualifier();
 
       // Check for auto functions and trailing return type and adjust the
       // return type accordingly.
       if (!D.isInvalidType()) {
         // trailing-return-type is only required if we're declaring a function,
         // and not, for instance, a pointer to a function.
         if (D.getDeclSpec().hasAutoTypeSpec() &&
             !FTI.hasTrailingReturnType() && chunkIndex == 0) {
           if (!S.getLangOpts().CPlusPlus14) {
case DeclaratorChunk::Function: {
           T = Context.getFunctionNoProtoType(T, EI);
           break;
         }
 
         FunctionProtoType::ExtProtoInfo EPI;
         EPI.ExtInfo = EI;
         EPI.Variadic = FTI.isVariadic;
         EPI.HasTrailingReturn = FTI.hasTrailingReturnType();
-        EPI.TypeQuals.addCVRUQualifiers(FTI.TypeQuals);
+        EPI.TypeQuals.addCVRUQualifiers(
+            FTI.MethodQualifiers ? FTI.MethodQualifiers->getTypeQualifiers()
+                                 : 0);
         EPI.RefQualifier = !FTI.hasRefQualifier()? RQ_None
                     : FTI.RefQualifierIsLValueRef? RQ_LValue
                     : RQ_RValue;
 
         // Otherwise, we have a function with a parameter list that is
         // potentially variadic.
         SmallVector<QualType, 16> ParamTys;
         ParamTys.reserve(FTI.NumParams);
if (IsQualifiedFunction &&
         D.getContext() != DeclaratorContext::TemplateTypeArgContext) {
       SourceLocation Loc = D.getBeginLoc();
       SourceRange RemovalRange;
       unsigned I;
       if (D.isFunctionDeclarator(I)) {
         SmallVector<SourceLocation, 4> RemovalLocs;
         const DeclaratorChunk &Chunk = D.getTypeObject(I);
         assert(Chunk.Kind == DeclaratorChunk::Function);
+
         if (Chunk.Fun.hasRefQualifier())
           RemovalLocs.push_back(Chunk.Fun.getRefQualifierLoc());
-        if (Chunk.Fun.TypeQuals & Qualifiers::Const)
-          RemovalLocs.push_back(Chunk.Fun.getConstQualifierLoc());
-        if (Chunk.Fun.TypeQuals & Qualifiers::Volatile)
-          RemovalLocs.push_back(Chunk.Fun.getVolatileQualifierLoc());
-        if (Chunk.Fun.TypeQuals & Qualifiers::Restrict)
-          RemovalLocs.push_back(Chunk.Fun.getRestrictQualifierLoc());
+
+        if (Chunk.Fun.MethodQualifiers)
+          Chunk.Fun.MethodQualifiers->forEachQualifier(
+              [&](DeclSpec::TQ TypeQual, StringRef QualName,
+                  SourceLocation SL) { RemovalLocs.push_back(SL); });
+
         if (!RemovalLocs.empty()) {
           llvm::sort(RemovalLocs,
                      BeforeThanCompare<SourceLocation>(S.getSourceManager()));
           RemovalRange = SourceRange(RemovalLocs.front(), RemovalLocs.back());
           Loc = RemovalLocs.front();
         }
       }