[clang][AST] Encapsulate DeclarationNameLoc, NFCI

This change makes `DeclarationNameLoc` a proper class and refactors its
users to use getter methods instead of accessing the members directly.
The change also makes `DeclarationNameLoc` immutable (i.e., it cannot
be modified once constructed).

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D94596

9 files changed, 110 insertions, 74 deletions

diff --git a/clang/include/clang/AST/DeclarationName.h b/clang/include/clang/AST/DeclarationName.h
index 3cb0a02..acf7e24 100644
--- a/clang/include/clang/AST/DeclarationName.h
+++ b/clang/include/clang/AST/DeclarationName.h
@@ -647,7 +647,7 @@ public:
 /// DeclarationNameLoc - Additional source/type location info
 /// for a declaration name. Needs a DeclarationName in order
 /// to be interpreted correctly.
-struct DeclarationNameLoc {
+class DeclarationNameLoc {
   // The source location for identifier stored elsewhere.
   // struct {} Identifier;
 
@@ -679,10 +679,78 @@ struct DeclarationNameLoc {
     struct CXXLitOpName CXXLiteralOperatorName;
   };
 
-  DeclarationNameLoc(DeclarationName Name);
+  void setNamedTypeLoc(TypeSourceInfo *TInfo) { NamedType.TInfo = TInfo; }
+
+  void setCXXOperatorNameRange(SourceRange Range) {
+    CXXOperatorName.BeginOpNameLoc = Range.getBegin().getRawEncoding();
+    CXXOperatorName.EndOpNameLoc = Range.getEnd().getRawEncoding();
+  }
 
+  void setCXXLiteralOperatorNameLoc(SourceLocation Loc) {
+    CXXLiteralOperatorName.OpNameLoc = Loc.getRawEncoding();
+  }
+
+public:
+  DeclarationNameLoc(DeclarationName Name);
   // FIXME: this should go away once all DNLocs are properly initialized.
   DeclarationNameLoc() { memset((void*) this, 0, sizeof(*this)); }
+
+  /// Returns the source type info. Assumes that the object stores location
+  /// information of a constructor, destructor or conversion operator.
+  TypeSourceInfo *getNamedTypeInfo() const { return NamedType.TInfo; }
+
+  /// Return the beginning location of the getCXXOperatorNameRange() range.
+  SourceLocation getCXXOperatorNameBeginLoc() const {
+    return SourceLocation::getFromRawEncoding(CXXOperatorName.BeginOpNameLoc);
+  }
+
+  /// Return the end location of the getCXXOperatorNameRange() range.
+  SourceLocation getCXXOperatorNameEndLoc() const {
+    return SourceLocation::getFromRawEncoding(CXXOperatorName.EndOpNameLoc);
+  }
+
+  /// Return the range of the operator name (without the operator keyword).
+  /// Assumes that the object stores location information of a (non-literal)
+  /// operator.
+  SourceRange getCXXOperatorNameRange() const {
+    return SourceRange(getCXXOperatorNameBeginLoc(),
+                       getCXXOperatorNameEndLoc());
+  }
+
+  /// Return the location of the literal operator name (without the operator
+  /// keyword). Assumes that the object stores location information of a literal
+  /// operator.
+  SourceLocation getCXXLiteralOperatorNameLoc() const {
+    return SourceLocation::getFromRawEncoding(CXXLiteralOperatorName.OpNameLoc);
+  }
+
+  /// Construct location information for a constructor, destructor or conversion
+  /// operator.
+  static DeclarationNameLoc makeNamedTypeLoc(TypeSourceInfo *TInfo) {
+    DeclarationNameLoc DNL;
+    DNL.setNamedTypeLoc(TInfo);
+    return DNL;
+  }
+
+  /// Construct location information for a non-literal C++ operator.
+  static DeclarationNameLoc makeCXXOperatorNameLoc(SourceLocation BeginLoc,
+                                                   SourceLocation EndLoc) {
+    return makeCXXOperatorNameLoc(SourceRange(BeginLoc, EndLoc));
+  }
+
+  /// Construct location information for a non-literal C++ operator.
+  static DeclarationNameLoc makeCXXOperatorNameLoc(SourceRange Range) {
+    DeclarationNameLoc DNL;
+    DNL.setCXXOperatorNameRange(Range);
+    return DNL;
+  }
+
+  /// Construct location information for a literal C++ operator.
+  static DeclarationNameLoc makeCXXLiteralOperatorNameLoc(SourceLocation Loc) {
+    DeclarationNameLoc DNL;
+    DNL.setCXXLiteralOperatorNameLoc(Loc);
+    return DNL;
+  }
 };
 
 /// DeclarationNameInfo - A collector data type for bundling together
@@ -722,7 +790,6 @@ public:
   void setLoc(SourceLocation L) { NameLoc = L; }
 
   const DeclarationNameLoc &getInfo() const { return LocInfo; }
-  DeclarationNameLoc &getInfo() { return LocInfo; }
   void setInfo(const DeclarationNameLoc &Info) { LocInfo = Info; }
 
   /// getNamedTypeInfo - Returns the source type info associated to
@@ -732,7 +799,7 @@ public:
         Name.getNameKind() != DeclarationName::CXXDestructorName &&
         Name.getNameKind() != DeclarationName::CXXConversionFunctionName)
       return nullptr;
-    return LocInfo.NamedType.TInfo;
+    return LocInfo.getNamedTypeInfo();
   }
 
   /// setNamedTypeInfo - Sets the source type info associated to
@@ -741,7 +808,7 @@ public:
     assert(Name.getNameKind() == DeclarationName::CXXConstructorName ||
            Name.getNameKind() == DeclarationName::CXXDestructorName ||
            Name.getNameKind() == DeclarationName::CXXConversionFunctionName);
-    LocInfo.NamedType.TInfo = TInfo;
+    LocInfo = DeclarationNameLoc::makeNamedTypeLoc(TInfo);
   }
 
   /// getCXXOperatorNameRange - Gets the range of the operator name
@@ -749,18 +816,14 @@ public:
   SourceRange getCXXOperatorNameRange() const {
     if (Name.getNameKind() != DeclarationName::CXXOperatorName)
       return SourceRange();
-    return SourceRange(
-     SourceLocation::getFromRawEncoding(LocInfo.CXXOperatorName.BeginOpNameLoc),
-     SourceLocation::getFromRawEncoding(LocInfo.CXXOperatorName.EndOpNameLoc)
-                       );
+    return LocInfo.getCXXOperatorNameRange();
   }
 
   /// setCXXOperatorNameRange - Sets the range of the operator name
   /// (without the operator keyword). Assumes it is a C++ operator.
   void setCXXOperatorNameRange(SourceRange R) {
     assert(Name.getNameKind() == DeclarationName::CXXOperatorName);
-    LocInfo.CXXOperatorName.BeginOpNameLoc = R.getBegin().getRawEncoding();
-    LocInfo.CXXOperatorName.EndOpNameLoc = R.getEnd().getRawEncoding();
+    LocInfo = DeclarationNameLoc::makeCXXOperatorNameLoc(R);
   }
 
   /// getCXXLiteralOperatorNameLoc - Returns the location of the literal
@@ -769,8 +832,7 @@ public:
   SourceLocation getCXXLiteralOperatorNameLoc() const {
     if (Name.getNameKind() != DeclarationName::CXXLiteralOperatorName)
       return SourceLocation();
-    return SourceLocation::
-      getFromRawEncoding(LocInfo.CXXLiteralOperatorName.OpNameLoc);
+    return LocInfo.getCXXLiteralOperatorNameLoc();
   }
 
   /// setCXXLiteralOperatorNameLoc - Sets the location of the literal
@@ -778,7 +840,7 @@ public:
   /// Assumes it is a literal operator.
   void setCXXLiteralOperatorNameLoc(SourceLocation Loc) {
     assert(Name.getNameKind() == DeclarationName::CXXLiteralOperatorName);
-    LocInfo.CXXLiteralOperatorName.OpNameLoc = Loc.getRawEncoding();
+    LocInfo = DeclarationNameLoc::makeCXXLiteralOperatorNameLoc(Loc);
   }
 
   /// Determine whether this name involves a template parameter.
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index cb7f00a..6b8425f 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -5840,9 +5840,8 @@ ASTContext::getNameForTemplate(TemplateName Name,
     } else {
       DName = DeclarationNames.getCXXOperatorName(DTN->getOperator());
       // DNInfo work in progress: FIXME: source locations?
-      DeclarationNameLoc DNLoc;
-      DNLoc.CXXOperatorName.BeginOpNameLoc = SourceLocation().getRawEncoding();
-      DNLoc.CXXOperatorName.EndOpNameLoc = SourceLocation().getRawEncoding();
+      DeclarationNameLoc DNLoc =
+          DeclarationNameLoc::makeCXXOperatorNameLoc(SourceRange());
       return DeclarationNameInfo(DName, NameLoc, DNLoc);
     }
   }
diff --git a/clang/lib/AST/DeclarationName.cpp b/clang/lib/AST/DeclarationName.cpp
index ecf676c..56cf4b4 100644
--- a/clang/lib/AST/DeclarationName.cpp
+++ b/clang/lib/AST/DeclarationName.cpp
@@ -392,14 +392,13 @@ DeclarationNameLoc::DeclarationNameLoc(DeclarationName Name) {
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    NamedType.TInfo = nullptr;
+    setNamedTypeLoc(nullptr);
     break;
   case DeclarationName::CXXOperatorName:
-    CXXOperatorName.BeginOpNameLoc = SourceLocation().getRawEncoding();
-    CXXOperatorName.EndOpNameLoc = SourceLocation().getRawEncoding();
+    setCXXOperatorNameRange(SourceRange());
     break;
   case DeclarationName::CXXLiteralOperatorName:
-    CXXLiteralOperatorName.OpNameLoc = SourceLocation().getRawEncoding();
+    setCXXLiteralOperatorNameLoc(SourceLocation());
     break;
   case DeclarationName::ObjCZeroArgSelector:
   case DeclarationName::ObjCOneArgSelector:
@@ -426,7 +425,7 @@ bool DeclarationNameInfo::containsUnexpandedParameterPack() const {
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    if (TypeSourceInfo *TInfo = LocInfo.NamedType.TInfo)
+    if (TypeSourceInfo *TInfo = LocInfo.getNamedTypeInfo())
       return TInfo->getType()->containsUnexpandedParameterPack();
 
     return Name.getCXXNameType()->containsUnexpandedParameterPack();
@@ -449,7 +448,7 @@ bool DeclarationNameInfo::isInstantiationDependent() const {
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    if (TypeSourceInfo *TInfo = LocInfo.NamedType.TInfo)
+    if (TypeSourceInfo *TInfo = LocInfo.getNamedTypeInfo())
       return TInfo->getType()->isInstantiationDependentType();
 
     return Name.getCXXNameType()->isInstantiationDependentType();
@@ -486,7 +485,7 @@ void DeclarationNameInfo::printName(raw_ostream &OS, PrintingPolicy Policy) cons
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    if (TypeSourceInfo *TInfo = LocInfo.NamedType.TInfo) {
+    if (TypeSourceInfo *TInfo = LocInfo.getNamedTypeInfo()) {
       if (Name.getNameKind() == DeclarationName::CXXDestructorName)
         OS << '~';
       else if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName)
@@ -508,20 +507,16 @@ SourceLocation DeclarationNameInfo::getEndLocPrivate() const {
   case DeclarationName::CXXDeductionGuideName:
     return NameLoc;
 
-  case DeclarationName::CXXOperatorName: {
-    unsigned raw = LocInfo.CXXOperatorName.EndOpNameLoc;
-    return SourceLocation::getFromRawEncoding(raw);
-  }
+  case DeclarationName::CXXOperatorName:
+    return LocInfo.getCXXOperatorNameEndLoc();
 
-  case DeclarationName::CXXLiteralOperatorName: {
-    unsigned raw = LocInfo.CXXLiteralOperatorName.OpNameLoc;
-    return SourceLocation::getFromRawEncoding(raw);
-  }
+  case DeclarationName::CXXLiteralOperatorName:
+    return LocInfo.getCXXLiteralOperatorNameLoc();
 
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    if (TypeSourceInfo *TInfo = LocInfo.NamedType.TInfo)
+    if (TypeSourceInfo *TInfo = LocInfo.getNamedTypeInfo())
       return TInfo->getTypeLoc().getEndLoc();
     else
       return NameLoc;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 3ee0c43..ef4947b 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5351,10 +5351,8 @@ Sema::GetNameFromUnqualifiedId(const UnqualifiedId &Name) {
   case UnqualifiedIdKind::IK_OperatorFunctionId:
     NameInfo.setName(Context.DeclarationNames.getCXXOperatorName(
                                            Name.OperatorFunctionId.Operator));
-    NameInfo.getInfo().CXXOperatorName.BeginOpNameLoc =
-        Name.OperatorFunctionId.SymbolLocations[0].getRawEncoding();
-    NameInfo.getInfo().CXXOperatorName.EndOpNameLoc
-      = Name.EndLocation.getRawEncoding();
+    NameInfo.setCXXOperatorNameRange(SourceRange(
+        Name.OperatorFunctionId.SymbolLocations[0], Name.EndLocation));
     return NameInfo;
 
   case UnqualifiedIdKind::IK_LiteralOperatorId:
diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index af61c82..f066acf 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -386,11 +386,8 @@ CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class,
   //   trailing-return-type respectively.
   DeclarationName MethodName
     = Context.DeclarationNames.getCXXOperatorName(OO_Call);
-  DeclarationNameLoc MethodNameLoc;
-  MethodNameLoc.CXXOperatorName.BeginOpNameLoc
-    = IntroducerRange.getBegin().getRawEncoding();
-  MethodNameLoc.CXXOperatorName.EndOpNameLoc
-    = IntroducerRange.getEnd().getRawEncoding();
+  DeclarationNameLoc MethodNameLoc =
+      DeclarationNameLoc::makeCXXOperatorNameLoc(IntroducerRange);
   CXXMethodDecl *Method = CXXMethodDecl::Create(
       Context, Class, EndLoc,
       DeclarationNameInfo(MethodName, IntroducerRange.getBegin(),
@@ -1378,7 +1375,6 @@ static void addFunctionPointerConversion(Sema &S, SourceRange IntroducerRange,
   DeclarationName ConversionName
     = S.Context.DeclarationNames.getCXXConversionFunctionName(
         S.Context.getCanonicalType(PtrToFunctionTy));
-  DeclarationNameLoc ConvNameLoc;
   // Construct a TypeSourceInfo for the conversion function, and wire
   // all the parameters appropriately for the FunctionProtoTypeLoc
   // so that everything works during transformation/instantiation of
@@ -1397,7 +1393,8 @@ static void addFunctionPointerConversion(Sema &S, SourceRange IntroducerRange,
   // operators ParmVarDecls below.
   TypeSourceInfo *ConvNamePtrToFunctionTSI =
       S.Context.getTrivialTypeSourceInfo(PtrToFunctionTy, Loc);
-  ConvNameLoc.NamedType.TInfo = ConvNamePtrToFunctionTSI;
+  DeclarationNameLoc ConvNameLoc =
+      DeclarationNameLoc::makeNamedTypeLoc(ConvNamePtrToFunctionTSI);
 
   // The conversion function is a conversion to a pointer-to-function.
   TypeSourceInfo *ConvTSI = S.Context.getTrivialTypeSourceInfo(ConvTy, Loc);
@@ -1548,8 +1545,8 @@ static void addBlockPointerConversion(Sema &S,
   DeclarationName Name
     = S.Context.DeclarationNames.getCXXConversionFunctionName(
         S.Context.getCanonicalType(BlockPtrTy));
-  DeclarationNameLoc NameLoc;
-  NameLoc.NamedType.TInfo = S.Context.getTrivialTypeSourceInfo(BlockPtrTy, Loc);
+  DeclarationNameLoc NameLoc = DeclarationNameLoc::makeNamedTypeLoc(
+      S.Context.getTrivialTypeSourceInfo(BlockPtrTy, Loc));
   CXXConversionDecl *Conversion = CXXConversionDecl::Create(
       S.Context, Class, Loc, DeclarationNameInfo(Name, Loc, NameLoc), ConvTy,
       S.Context.getTrivialTypeSourceInfo(ConvTy, Loc),
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 0a596e5..9da07a1 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -14334,11 +14334,9 @@ TreeTransform<Derived>::RebuildCXXOperatorCallExpr(OverloadedOperatorKind Op,
     SourceLocation RBrace;
 
     if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Callee)) {
-        DeclarationNameLoc NameLoc = DRE->getNameInfo().getInfo();
-        LBrace = SourceLocation::getFromRawEncoding(
-                    NameLoc.CXXOperatorName.BeginOpNameLoc);
-        RBrace = SourceLocation::getFromRawEncoding(
-                    NameLoc.CXXOperatorName.EndOpNameLoc);
+      DeclarationNameLoc NameLoc = DRE->getNameInfo().getInfo();
+      LBrace = NameLoc.getCXXOperatorNameBeginLoc();
+      RBrace = NameLoc.getCXXOperatorNameEndLoc();
     } else {
       LBrace = Callee->getBeginLoc();
       RBrace = OpLoc;
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 1f68f6bc..85add2e 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -8737,25 +8737,18 @@ ASTReader::getGlobalSelectorID(ModuleFile &M, unsigned LocalID) const {
 
 DeclarationNameLoc
 ASTRecordReader::readDeclarationNameLoc(DeclarationName Name) {
-  DeclarationNameLoc DNLoc;
   switch (Name.getNameKind()) {
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    DNLoc.NamedType.TInfo = readTypeSourceInfo();
-    break;
+    return DeclarationNameLoc::makeNamedTypeLoc(readTypeSourceInfo());
 
   case DeclarationName::CXXOperatorName:
-    DNLoc.CXXOperatorName.BeginOpNameLoc
-      = readSourceLocation().getRawEncoding();
-    DNLoc.CXXOperatorName.EndOpNameLoc
-      = readSourceLocation().getRawEncoding();
-    break;
+    return DeclarationNameLoc::makeCXXOperatorNameLoc(readSourceRange());
 
   case DeclarationName::CXXLiteralOperatorName:
-    DNLoc.CXXLiteralOperatorName.OpNameLoc
-      = readSourceLocation().getRawEncoding();
-    break;
+    return DeclarationNameLoc::makeCXXLiteralOperatorNameLoc(
+        readSourceLocation());
 
   case DeclarationName::Identifier:
   case DeclarationName::ObjCZeroArgSelector:
@@ -8765,7 +8758,7 @@ ASTRecordReader::readDeclarationNameLoc(DeclarationName Name) {
   case DeclarationName::CXXDeductionGuideName:
     break;
   }
-  return DNLoc;
+  return DeclarationNameLoc();
 }
 
 DeclarationNameInfo ASTRecordReader::readDeclarationNameInfo() {
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 6bfa7b0..b940020 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5413,19 +5413,15 @@ void ASTRecordWriter::AddDeclarationNameLoc(const DeclarationNameLoc &DNLoc,
   case DeclarationName::CXXConstructorName:
   case DeclarationName::CXXDestructorName:
   case DeclarationName::CXXConversionFunctionName:
-    AddTypeSourceInfo(DNLoc.NamedType.TInfo);
+    AddTypeSourceInfo(DNLoc.getNamedTypeInfo());
     break;
 
   case DeclarationName::CXXOperatorName:
-    AddSourceLocation(SourceLocation::getFromRawEncoding(
-        DNLoc.CXXOperatorName.BeginOpNameLoc));
-    AddSourceLocation(
-        SourceLocation::getFromRawEncoding(DNLoc.CXXOperatorName.EndOpNameLoc));
+    AddSourceRange(DNLoc.getCXXOperatorNameRange());
     break;
 
   case DeclarationName::CXXLiteralOperatorName:
-    AddSourceLocation(SourceLocation::getFromRawEncoding(
-        DNLoc.CXXLiteralOperatorName.OpNameLoc));
+    AddSourceLocation(DNLoc.getCXXLiteralOperatorNameLoc());
     break;
 
   case DeclarationName::Identifier:
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index f100831..3ae30c1 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -3351,10 +3351,8 @@ RefNamePieces buildPieces(unsigned NameFlags, bool IsMemberRefExpr,
     Pieces.push_back(*TemplateArgsLoc);
 
   if (Kind == DeclarationName::CXXOperatorName) {
-    Pieces.push_back(SourceLocation::getFromRawEncoding(
-        NI.getInfo().CXXOperatorName.BeginOpNameLoc));
-    Pieces.push_back(SourceLocation::getFromRawEncoding(
-        NI.getInfo().CXXOperatorName.EndOpNameLoc));
+    Pieces.push_back(NI.getInfo().getCXXOperatorNameBeginLoc());
+    Pieces.push_back(NI.getInfo().getCXXOperatorNameEndLoc());
   }
 
   if (WantSinglePiece) {