[Lldb-commits] [lldb] fca5191 - [NFC][Clang] Improve const correctness for IdentifierInfo (#79365)

via lldb-commits lldb-commits at lists.llvm.org
Wed Apr 10 17:33:44 PDT 2024


Author: Bill Wendling
Date: 2024-04-11T00:33:40Z
New Revision: fca51911d4668b3a6b79eb956327eb81fad3f40c

URL: https://github.com/llvm/llvm-project/commit/fca51911d4668b3a6b79eb956327eb81fad3f40c
DIFF: https://github.com/llvm/llvm-project/commit/fca51911d4668b3a6b79eb956327eb81fad3f40c.diff

LOG: [NFC][Clang] Improve const correctness for IdentifierInfo (#79365)

The IdentifierInfo isn't typically modified. Use 'const' wherever
possible.

Added: 
    

Modified: 
    clang/include/clang/AST/ASTContext.h
    clang/include/clang/AST/Decl.h
    clang/include/clang/AST/DeclObjC.h
    clang/include/clang/AST/DeclTemplate.h
    clang/include/clang/AST/ExprCXX.h
    clang/include/clang/AST/ExternalASTSource.h
    clang/include/clang/AST/NestedNameSpecifier.h
    clang/include/clang/Analysis/SelectorExtras.h
    clang/include/clang/Basic/IdentifierTable.h
    clang/include/clang/Lex/ExternalPreprocessorSource.h
    clang/include/clang/Lex/MacroInfo.h
    clang/include/clang/Lex/Preprocessor.h
    clang/include/clang/Parse/Parser.h
    clang/include/clang/Sema/CodeCompleteConsumer.h
    clang/include/clang/Sema/DeclSpec.h
    clang/include/clang/Sema/ParsedTemplate.h
    clang/include/clang/Sema/Sema.h
    clang/include/clang/Serialization/ASTReader.h
    clang/lib/ARCMigrate/ObjCMT.cpp
    clang/lib/ARCMigrate/TransAPIUses.cpp
    clang/lib/AST/ASTContext.cpp
    clang/lib/AST/ASTImporter.cpp
    clang/lib/AST/Decl.cpp
    clang/lib/AST/DeclObjC.cpp
    clang/lib/AST/DeclTemplate.cpp
    clang/lib/AST/NSAPI.cpp
    clang/lib/AST/NestedNameSpecifier.cpp
    clang/lib/AST/SelectorLocationsKind.cpp
    clang/lib/AST/StmtPrinter.cpp
    clang/lib/AST/StmtProfile.cpp
    clang/lib/Analysis/ObjCNoReturn.cpp
    clang/lib/Basic/IdentifierTable.cpp
    clang/lib/CodeGen/CGBlocks.cpp
    clang/lib/CodeGen/CGCUDANV.cpp
    clang/lib/CodeGen/CGDecl.cpp
    clang/lib/CodeGen/CGObjC.cpp
    clang/lib/CodeGen/CGObjCMac.cpp
    clang/lib/CodeGen/CodeGenFunction.cpp
    clang/lib/CodeGen/CodeGenModule.cpp
    clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
    clang/lib/Lex/HeaderSearch.cpp
    clang/lib/Lex/MacroInfo.cpp
    clang/lib/Lex/PPLexerChange.cpp
    clang/lib/Lex/PPMacroExpansion.cpp
    clang/lib/Lex/Preprocessor.cpp
    clang/lib/Parse/ParseDecl.cpp
    clang/lib/Parse/ParseDeclCXX.cpp
    clang/lib/Parse/ParseExprCXX.cpp
    clang/lib/Parse/ParseObjc.cpp
    clang/lib/Parse/ParseTemplate.cpp
    clang/lib/Sema/CodeCompleteConsumer.cpp
    clang/lib/Sema/Sema.cpp
    clang/lib/Sema/SemaCodeComplete.cpp
    clang/lib/Sema/SemaDecl.cpp
    clang/lib/Sema/SemaDeclCXX.cpp
    clang/lib/Sema/SemaDeclObjC.cpp
    clang/lib/Sema/SemaExprCXX.cpp
    clang/lib/Sema/SemaExprObjC.cpp
    clang/lib/Sema/SemaObjCProperty.cpp
    clang/lib/Sema/SemaOpenMP.cpp
    clang/lib/Sema/SemaPseudoObject.cpp
    clang/lib/Sema/SemaStmt.cpp
    clang/lib/Sema/SemaTemplate.cpp
    clang/lib/Serialization/ASTCommon.cpp
    clang/lib/Serialization/ASTReader.cpp
    clang/lib/Serialization/ASTWriter.cpp
    clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
    clang/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
    clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp
    clang/lib/StaticAnalyzer/Checkers/ObjCMissingSuperCallChecker.cpp
    clang/lib/StaticAnalyzer/Checkers/ObjCSuperDeallocChecker.cpp
    clang/tools/libclang/CIndexCodeCompletion.cpp
    lldb/source/Plugins/ExpressionParser/Clang/ASTUtils.h
    lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
    lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
    lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index 08f71051e6cbf3..28f8d67811f0a2 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -3411,13 +3411,13 @@ const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
 
 /// Utility function for constructing a nullary selector.
 inline Selector GetNullarySelector(StringRef name, ASTContext &Ctx) {
-  IdentifierInfo* II = &Ctx.Idents.get(name);
+  const IdentifierInfo *II = &Ctx.Idents.get(name);
   return Ctx.Selectors.getSelector(0, &II);
 }
 
 /// Utility function for constructing an unary selector.
 inline Selector GetUnarySelector(StringRef name, ASTContext &Ctx) {
-  IdentifierInfo* II = &Ctx.Idents.get(name);
+  const IdentifierInfo *II = &Ctx.Idents.get(name);
   return Ctx.Selectors.getSelector(1, &II);
 }
 

diff  --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 5f1f83bb00282f..ed6790acdfc7cc 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -1731,7 +1731,7 @@ class ImplicitParamDecl : public VarDecl {
   static ImplicitParamDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
   ImplicitParamDecl(ASTContext &C, DeclContext *DC, SourceLocation IdLoc,
-                    IdentifierInfo *Id, QualType Type,
+                    const IdentifierInfo *Id, QualType Type,
                     ImplicitParamKind ParamKind)
       : VarDecl(ImplicitParam, C, DC, IdLoc, IdLoc, Id, Type,
                 /*TInfo=*/nullptr, SC_None) {
@@ -1765,7 +1765,7 @@ class ParmVarDecl : public VarDecl {
 
 protected:
   ParmVarDecl(Kind DK, ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
-              SourceLocation IdLoc, IdentifierInfo *Id, QualType T,
+              SourceLocation IdLoc, const IdentifierInfo *Id, QualType T,
               TypeSourceInfo *TInfo, StorageClass S, Expr *DefArg)
       : VarDecl(DK, C, DC, StartLoc, IdLoc, Id, T, TInfo, S) {
     assert(ParmVarDeclBits.HasInheritedDefaultArg == false);
@@ -1777,10 +1777,10 @@ class ParmVarDecl : public VarDecl {
 
 public:
   static ParmVarDecl *Create(ASTContext &C, DeclContext *DC,
-                             SourceLocation StartLoc,
-                             SourceLocation IdLoc, IdentifierInfo *Id,
-                             QualType T, TypeSourceInfo *TInfo,
-                             StorageClass S, Expr *DefArg);
+                             SourceLocation StartLoc, SourceLocation IdLoc,
+                             const IdentifierInfo *Id, QualType T,
+                             TypeSourceInfo *TInfo, StorageClass S,
+                             Expr *DefArg);
 
   static ParmVarDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
@@ -3095,7 +3095,7 @@ class FieldDecl : public DeclaratorDecl, public Mergeable<FieldDecl> {
 
 protected:
   FieldDecl(Kind DK, DeclContext *DC, SourceLocation StartLoc,
-            SourceLocation IdLoc, IdentifierInfo *Id, QualType T,
+            SourceLocation IdLoc, const IdentifierInfo *Id, QualType T,
             TypeSourceInfo *TInfo, Expr *BW, bool Mutable,
             InClassInitStyle InitStyle)
       : DeclaratorDecl(DK, DC, IdLoc, Id, T, TInfo, StartLoc), BitField(false),
@@ -3111,7 +3111,7 @@ class FieldDecl : public DeclaratorDecl, public Mergeable<FieldDecl> {
 
   static FieldDecl *Create(const ASTContext &C, DeclContext *DC,
                            SourceLocation StartLoc, SourceLocation IdLoc,
-                           IdentifierInfo *Id, QualType T,
+                           const IdentifierInfo *Id, QualType T,
                            TypeSourceInfo *TInfo, Expr *BW, bool Mutable,
                            InClassInitStyle InitStyle);
 
@@ -3332,8 +3332,9 @@ class IndirectFieldDecl : public ValueDecl,
   friend class ASTDeclReader;
 
   static IndirectFieldDecl *Create(ASTContext &C, DeclContext *DC,
-                                   SourceLocation L, IdentifierInfo *Id,
-                                   QualType T, llvm::MutableArrayRef<NamedDecl *> CH);
+                                   SourceLocation L, const IdentifierInfo *Id,
+                                   QualType T,
+                                   llvm::MutableArrayRef<NamedDecl *> CH);
 
   static IndirectFieldDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
@@ -3381,9 +3382,9 @@ class TypeDecl : public NamedDecl {
   void anchor() override;
 
 protected:
-  TypeDecl(Kind DK, DeclContext *DC, SourceLocation L, IdentifierInfo *Id,
+  TypeDecl(Kind DK, DeclContext *DC, SourceLocation L, const IdentifierInfo *Id,
            SourceLocation StartL = SourceLocation())
-    : NamedDecl(DK, DC, L, Id), LocStart(StartL) {}
+      : NamedDecl(DK, DC, L, Id), LocStart(StartL) {}
 
 public:
   // Low-level accessor. If you just want the type defined by this node,
@@ -3425,7 +3426,7 @@ class TypedefNameDecl : public TypeDecl, public Redeclarable<TypedefNameDecl> {
 protected:
   TypedefNameDecl(Kind DK, ASTContext &C, DeclContext *DC,
                   SourceLocation StartLoc, SourceLocation IdLoc,
-                  IdentifierInfo *Id, TypeSourceInfo *TInfo)
+                  const IdentifierInfo *Id, TypeSourceInfo *TInfo)
       : TypeDecl(DK, DC, IdLoc, Id, StartLoc), redeclarable_base(C),
         MaybeModedTInfo(TInfo, 0) {}
 
@@ -3512,13 +3513,14 @@ class TypedefNameDecl : public TypeDecl, public Redeclarable<TypedefNameDecl> {
 /// type specifier.
 class TypedefDecl : public TypedefNameDecl {
   TypedefDecl(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
-              SourceLocation IdLoc, IdentifierInfo *Id, TypeSourceInfo *TInfo)
+              SourceLocation IdLoc, const IdentifierInfo *Id,
+              TypeSourceInfo *TInfo)
       : TypedefNameDecl(Typedef, C, DC, StartLoc, IdLoc, Id, TInfo) {}
 
 public:
   static TypedefDecl *Create(ASTContext &C, DeclContext *DC,
                              SourceLocation StartLoc, SourceLocation IdLoc,
-                             IdentifierInfo *Id, TypeSourceInfo *TInfo);
+                             const IdentifierInfo *Id, TypeSourceInfo *TInfo);
   static TypedefDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
   SourceRange getSourceRange() const override LLVM_READONLY;
@@ -3535,14 +3537,15 @@ class TypeAliasDecl : public TypedefNameDecl {
   TypeAliasTemplateDecl *Template;
 
   TypeAliasDecl(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
-                SourceLocation IdLoc, IdentifierInfo *Id, TypeSourceInfo *TInfo)
+                SourceLocation IdLoc, const IdentifierInfo *Id,
+                TypeSourceInfo *TInfo)
       : TypedefNameDecl(TypeAlias, C, DC, StartLoc, IdLoc, Id, TInfo),
         Template(nullptr) {}
 
 public:
   static TypeAliasDecl *Create(ASTContext &C, DeclContext *DC,
                                SourceLocation StartLoc, SourceLocation IdLoc,
-                               IdentifierInfo *Id, TypeSourceInfo *TInfo);
+                               const IdentifierInfo *Id, TypeSourceInfo *TInfo);
   static TypeAliasDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
   SourceRange getSourceRange() const override LLVM_READONLY;

diff  --git a/clang/include/clang/AST/DeclObjC.h b/clang/include/clang/AST/DeclObjC.h
index f8f894b4b10d19..b8d17dd06d1550 100644
--- a/clang/include/clang/AST/DeclObjC.h
+++ b/clang/include/clang/AST/DeclObjC.h
@@ -772,7 +772,7 @@ class ObjCPropertyDecl : public NamedDecl {
   // Synthesize ivar for this property
   ObjCIvarDecl *PropertyIvarDecl = nullptr;
 
-  ObjCPropertyDecl(DeclContext *DC, SourceLocation L, IdentifierInfo *Id,
+  ObjCPropertyDecl(DeclContext *DC, SourceLocation L, const IdentifierInfo *Id,
                    SourceLocation AtLocation, SourceLocation LParenLocation,
                    QualType T, TypeSourceInfo *TSI, PropertyControl propControl)
       : NamedDecl(ObjCProperty, DC, L, Id), AtLoc(AtLocation),
@@ -782,10 +782,12 @@ class ObjCPropertyDecl : public NamedDecl {
         PropertyImplementation(propControl) {}
 
 public:
-  static ObjCPropertyDecl *
-  Create(ASTContext &C, DeclContext *DC, SourceLocation L, IdentifierInfo *Id,
-         SourceLocation AtLocation, SourceLocation LParenLocation, QualType T,
-         TypeSourceInfo *TSI, PropertyControl propControl = None);
+  static ObjCPropertyDecl *Create(ASTContext &C, DeclContext *DC,
+                                  SourceLocation L, const IdentifierInfo *Id,
+                                  SourceLocation AtLocation,
+                                  SourceLocation LParenLocation, QualType T,
+                                  TypeSourceInfo *TSI,
+                                  PropertyControl propControl = None);
 
   static ObjCPropertyDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
@@ -952,7 +954,7 @@ class ObjCContainerDecl : public NamedDecl, public DeclContext {
   void anchor() override;
 
 public:
-  ObjCContainerDecl(Kind DK, DeclContext *DC, IdentifierInfo *Id,
+  ObjCContainerDecl(Kind DK, DeclContext *DC, const IdentifierInfo *Id,
                     SourceLocation nameLoc, SourceLocation atStartLoc);
 
   // Iterator access to instance/class properties.
@@ -1240,7 +1242,7 @@ class ObjCInterfaceDecl : public ObjCContainerDecl
   llvm::PointerIntPair<DefinitionData *, 1, bool> Data;
 
   ObjCInterfaceDecl(const ASTContext &C, DeclContext *DC, SourceLocation AtLoc,
-                    IdentifierInfo *Id, ObjCTypeParamList *typeParamList,
+                    const IdentifierInfo *Id, ObjCTypeParamList *typeParamList,
                     SourceLocation CLoc, ObjCInterfaceDecl *PrevDecl,
                     bool IsInternal);
 
@@ -1271,13 +1273,11 @@ class ObjCInterfaceDecl : public ObjCContainerDecl
   }
 
 public:
-  static ObjCInterfaceDecl *Create(const ASTContext &C, DeclContext *DC,
-                                   SourceLocation atLoc,
-                                   IdentifierInfo *Id,
-                                   ObjCTypeParamList *typeParamList,
-                                   ObjCInterfaceDecl *PrevDecl,
-                                   SourceLocation ClassLoc = SourceLocation(),
-                                   bool isInternal = false);
+  static ObjCInterfaceDecl *
+  Create(const ASTContext &C, DeclContext *DC, SourceLocation atLoc,
+         const IdentifierInfo *Id, ObjCTypeParamList *typeParamList,
+         ObjCInterfaceDecl *PrevDecl,
+         SourceLocation ClassLoc = SourceLocation(), bool isInternal = false);
 
   static ObjCInterfaceDecl *CreateDeserialized(const ASTContext &C, unsigned ID);
 
@@ -1338,7 +1338,8 @@ class ObjCInterfaceDecl : public ObjCContainerDecl
   ObjCImplementationDecl *getImplementation() const;
   void setImplementation(ObjCImplementationDecl *ImplD);
 
-  ObjCCategoryDecl *FindCategoryDeclaration(IdentifierInfo *CategoryId) const;
+  ObjCCategoryDecl *
+  FindCategoryDeclaration(const IdentifierInfo *CategoryId) const;
 
   // Get the local instance/class method declared in a category.
   ObjCMethodDecl *getCategoryInstanceMethod(Selector Sel) const;
@@ -1794,9 +1795,9 @@ class ObjCInterfaceDecl : public ObjCContainerDecl
     data().CategoryList = category;
   }
 
-  ObjCPropertyDecl
-    *FindPropertyVisibleInPrimaryClass(IdentifierInfo *PropertyId,
-                                       ObjCPropertyQueryKind QueryKind) const;
+  ObjCPropertyDecl *
+  FindPropertyVisibleInPrimaryClass(const IdentifierInfo *PropertyId,
+                                    ObjCPropertyQueryKind QueryKind) const;
 
   void collectPropertiesToImplement(PropertyMap &PM) const override;
 
@@ -1954,8 +1955,8 @@ class ObjCIvarDecl : public FieldDecl {
 
 private:
   ObjCIvarDecl(ObjCContainerDecl *DC, SourceLocation StartLoc,
-               SourceLocation IdLoc, IdentifierInfo *Id,
-               QualType T, TypeSourceInfo *TInfo, AccessControl ac, Expr *BW,
+               SourceLocation IdLoc, const IdentifierInfo *Id, QualType T,
+               TypeSourceInfo *TInfo, AccessControl ac, Expr *BW,
                bool synthesized)
       : FieldDecl(ObjCIvar, DC, StartLoc, IdLoc, Id, T, TInfo, BW,
                   /*Mutable=*/false, /*HasInit=*/ICIS_NoInit),
@@ -1964,10 +1965,9 @@ class ObjCIvarDecl : public FieldDecl {
 public:
   static ObjCIvarDecl *Create(ASTContext &C, ObjCContainerDecl *DC,
                               SourceLocation StartLoc, SourceLocation IdLoc,
-                              IdentifierInfo *Id, QualType T,
-                              TypeSourceInfo *TInfo,
-                              AccessControl ac, Expr *BW = nullptr,
-                              bool synthesized=false);
+                              const IdentifierInfo *Id, QualType T,
+                              TypeSourceInfo *TInfo, AccessControl ac,
+                              Expr *BW = nullptr, bool synthesized = false);
 
   static ObjCIvarDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
@@ -2343,7 +2343,7 @@ class ObjCCategoryDecl : public ObjCContainerDecl {
 
   ObjCCategoryDecl(DeclContext *DC, SourceLocation AtLoc,
                    SourceLocation ClassNameLoc, SourceLocation CategoryNameLoc,
-                   IdentifierInfo *Id, ObjCInterfaceDecl *IDecl,
+                   const IdentifierInfo *Id, ObjCInterfaceDecl *IDecl,
                    ObjCTypeParamList *typeParamList,
                    SourceLocation IvarLBraceLoc = SourceLocation(),
                    SourceLocation IvarRBraceLoc = SourceLocation());
@@ -2354,15 +2354,13 @@ class ObjCCategoryDecl : public ObjCContainerDecl {
   friend class ASTDeclReader;
   friend class ASTDeclWriter;
 
-  static ObjCCategoryDecl *Create(ASTContext &C, DeclContext *DC,
-                                  SourceLocation AtLoc,
-                                  SourceLocation ClassNameLoc,
-                                  SourceLocation CategoryNameLoc,
-                                  IdentifierInfo *Id,
-                                  ObjCInterfaceDecl *IDecl,
-                                  ObjCTypeParamList *typeParamList,
-                                  SourceLocation IvarLBraceLoc=SourceLocation(),
-                                  SourceLocation IvarRBraceLoc=SourceLocation());
+  static ObjCCategoryDecl *
+  Create(ASTContext &C, DeclContext *DC, SourceLocation AtLoc,
+         SourceLocation ClassNameLoc, SourceLocation CategoryNameLoc,
+         const IdentifierInfo *Id, ObjCInterfaceDecl *IDecl,
+         ObjCTypeParamList *typeParamList,
+         SourceLocation IvarLBraceLoc = SourceLocation(),
+         SourceLocation IvarRBraceLoc = SourceLocation());
   static ObjCCategoryDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
   ObjCInterfaceDecl *getClassInterface() { return ClassInterface; }
@@ -2472,10 +2470,9 @@ class ObjCImplDecl : public ObjCContainerDecl {
   void anchor() override;
 
 protected:
-  ObjCImplDecl(Kind DK, DeclContext *DC,
-               ObjCInterfaceDecl *classInterface,
-               IdentifierInfo *Id,
-               SourceLocation nameLoc, SourceLocation atStartLoc)
+  ObjCImplDecl(Kind DK, DeclContext *DC, ObjCInterfaceDecl *classInterface,
+               const IdentifierInfo *Id, SourceLocation nameLoc,
+               SourceLocation atStartLoc)
       : ObjCContainerDecl(DK, DC, Id, nameLoc, atStartLoc),
         ClassInterface(classInterface) {}
 
@@ -2543,12 +2540,12 @@ class ObjCCategoryImplDecl : public ObjCImplDecl {
   // Category name location
   SourceLocation CategoryNameLoc;
 
-  ObjCCategoryImplDecl(DeclContext *DC, IdentifierInfo *Id,
+  ObjCCategoryImplDecl(DeclContext *DC, const IdentifierInfo *Id,
                        ObjCInterfaceDecl *classInterface,
                        SourceLocation nameLoc, SourceLocation atStartLoc,
                        SourceLocation CategoryNameLoc)
-      : ObjCImplDecl(ObjCCategoryImpl, DC, classInterface, Id,
-                     nameLoc, atStartLoc),
+      : ObjCImplDecl(ObjCCategoryImpl, DC, classInterface, Id, nameLoc,
+                     atStartLoc),
         CategoryNameLoc(CategoryNameLoc) {}
 
   void anchor() override;
@@ -2557,12 +2554,10 @@ class ObjCCategoryImplDecl : public ObjCImplDecl {
   friend class ASTDeclReader;
   friend class ASTDeclWriter;
 
-  static ObjCCategoryImplDecl *Create(ASTContext &C, DeclContext *DC,
-                                      IdentifierInfo *Id,
-                                      ObjCInterfaceDecl *classInterface,
-                                      SourceLocation nameLoc,
-                                      SourceLocation atStartLoc,
-                                      SourceLocation CategoryNameLoc);
+  static ObjCCategoryImplDecl *
+  Create(ASTContext &C, DeclContext *DC, const IdentifierInfo *Id,
+         ObjCInterfaceDecl *classInterface, SourceLocation nameLoc,
+         SourceLocation atStartLoc, SourceLocation CategoryNameLoc);
   static ObjCCategoryImplDecl *CreateDeserialized(ASTContext &C, unsigned ID);
 
   ObjCCategoryDecl *getCategoryDecl() const;

diff  --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
index e3b6a7efb1127a..cb598cb81840d1 100644
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -1389,14 +1389,14 @@ class NonTypeTemplateParmDecl final
 
   NonTypeTemplateParmDecl(DeclContext *DC, SourceLocation StartLoc,
                           SourceLocation IdLoc, unsigned D, unsigned P,
-                          IdentifierInfo *Id, QualType T,
+                          const IdentifierInfo *Id, QualType T,
                           bool ParameterPack, TypeSourceInfo *TInfo)
       : DeclaratorDecl(NonTypeTemplateParm, DC, IdLoc, Id, T, TInfo, StartLoc),
         TemplateParmPosition(D, P), ParameterPack(ParameterPack) {}
 
   NonTypeTemplateParmDecl(DeclContext *DC, SourceLocation StartLoc,
                           SourceLocation IdLoc, unsigned D, unsigned P,
-                          IdentifierInfo *Id, QualType T,
+                          const IdentifierInfo *Id, QualType T,
                           TypeSourceInfo *TInfo,
                           ArrayRef<QualType> ExpandedTypes,
                           ArrayRef<TypeSourceInfo *> ExpandedTInfos);
@@ -1404,12 +1404,12 @@ class NonTypeTemplateParmDecl final
 public:
   static NonTypeTemplateParmDecl *
   Create(const ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
-         SourceLocation IdLoc, unsigned D, unsigned P, IdentifierInfo *Id,
+         SourceLocation IdLoc, unsigned D, unsigned P, const IdentifierInfo *Id,
          QualType T, bool ParameterPack, TypeSourceInfo *TInfo);
 
   static NonTypeTemplateParmDecl *
   Create(const ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
-         SourceLocation IdLoc, unsigned D, unsigned P, IdentifierInfo *Id,
+         SourceLocation IdLoc, unsigned D, unsigned P, const IdentifierInfo *Id,
          QualType T, TypeSourceInfo *TInfo, ArrayRef<QualType> ExpandedTypes,
          ArrayRef<TypeSourceInfo *> ExpandedTInfos);
 

diff  --git a/clang/include/clang/AST/ExprCXX.h b/clang/include/clang/AST/ExprCXX.h
index 7eb99a75e1fc9d..d28e5c3a78ee4b 100644
--- a/clang/include/clang/AST/ExprCXX.h
+++ b/clang/include/clang/AST/ExprCXX.h
@@ -2559,7 +2559,7 @@ class CXXDeleteExpr : public Expr {
 class PseudoDestructorTypeStorage {
   /// Either the type source information or the name of the type, if
   /// it couldn't be resolved due to type-dependence.
-  llvm::PointerUnion<TypeSourceInfo *, IdentifierInfo *> Type;
+  llvm::PointerUnion<TypeSourceInfo *, const IdentifierInfo *> Type;
 
   /// The starting source location of the pseudo-destructor type.
   SourceLocation Location;
@@ -2567,7 +2567,7 @@ class PseudoDestructorTypeStorage {
 public:
   PseudoDestructorTypeStorage() = default;
 
-  PseudoDestructorTypeStorage(IdentifierInfo *II, SourceLocation Loc)
+  PseudoDestructorTypeStorage(const IdentifierInfo *II, SourceLocation Loc)
       : Type(II), Location(Loc) {}
 
   PseudoDestructorTypeStorage(TypeSourceInfo *Info);
@@ -2576,8 +2576,8 @@ class PseudoDestructorTypeStorage {
     return Type.dyn_cast<TypeSourceInfo *>();
   }
 
-  IdentifierInfo *getIdentifier() const {
-    return Type.dyn_cast<IdentifierInfo *>();
+  const IdentifierInfo *getIdentifier() const {
+    return Type.dyn_cast<const IdentifierInfo *>();
   }
 
   SourceLocation getLocation() const { return Location; }
@@ -2708,7 +2708,7 @@ class CXXPseudoDestructorExpr : public Expr {
   /// In a dependent pseudo-destructor expression for which we do not
   /// have full type information on the destroyed type, provides the name
   /// of the destroyed type.
-  IdentifierInfo *getDestroyedTypeIdentifier() const {
+  const IdentifierInfo *getDestroyedTypeIdentifier() const {
     return DestroyedType.getIdentifier();
   }
 

diff  --git a/clang/include/clang/AST/ExternalASTSource.h b/clang/include/clang/AST/ExternalASTSource.h
index 8e573965b0a336..230c83943c2224 100644
--- a/clang/include/clang/AST/ExternalASTSource.h
+++ b/clang/include/clang/AST/ExternalASTSource.h
@@ -138,7 +138,7 @@ class ExternalASTSource : public RefCountedBase<ExternalASTSource> {
   virtual CXXBaseSpecifier *GetExternalCXXBaseSpecifiers(uint64_t Offset);
 
   /// Update an out-of-date identifier.
-  virtual void updateOutOfDateIdentifier(IdentifierInfo &II) {}
+  virtual void updateOutOfDateIdentifier(const IdentifierInfo &II) {}
 
   /// Find all declarations with the given name in the given context,
   /// and add them to the context by calling SetExternalVisibleDeclsForName

diff  --git a/clang/include/clang/AST/NestedNameSpecifier.h b/clang/include/clang/AST/NestedNameSpecifier.h
index 3b6cf972118509..7b0c21b9e7cfb1 100644
--- a/clang/include/clang/AST/NestedNameSpecifier.h
+++ b/clang/include/clang/AST/NestedNameSpecifier.h
@@ -124,7 +124,7 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
   /// cannot be resolved.
   static NestedNameSpecifier *Create(const ASTContext &Context,
                                      NestedNameSpecifier *Prefix,
-                                     IdentifierInfo *II);
+                                     const IdentifierInfo *II);
 
   /// Builds a nested name specifier that names a namespace.
   static NestedNameSpecifier *Create(const ASTContext &Context,
@@ -134,7 +134,7 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
   /// Builds a nested name specifier that names a namespace alias.
   static NestedNameSpecifier *Create(const ASTContext &Context,
                                      NestedNameSpecifier *Prefix,
-                                     NamespaceAliasDecl *Alias);
+                                     const NamespaceAliasDecl *Alias);
 
   /// Builds a nested name specifier that names a type.
   static NestedNameSpecifier *Create(const ASTContext &Context,
@@ -148,7 +148,7 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
   /// nested name specifier, e.g., in "x->Base::f", the "x" has a dependent
   /// type.
   static NestedNameSpecifier *Create(const ASTContext &Context,
-                                     IdentifierInfo *II);
+                                     const IdentifierInfo *II);
 
   /// Returns the nested name specifier representing the global
   /// scope.

diff  --git a/clang/include/clang/Analysis/SelectorExtras.h b/clang/include/clang/Analysis/SelectorExtras.h
index 1e1daf5706bbf5..ac2c2519beae35 100644
--- a/clang/include/clang/Analysis/SelectorExtras.h
+++ b/clang/include/clang/Analysis/SelectorExtras.h
@@ -15,10 +15,10 @@ namespace clang {
 
 template <typename... IdentifierInfos>
 static inline Selector getKeywordSelector(ASTContext &Ctx,
-                                          IdentifierInfos *... IIs) {
+                                          const IdentifierInfos *...IIs) {
   static_assert(sizeof...(IdentifierInfos) > 0,
                 "keyword selectors must have at least one argument");
-  SmallVector<IdentifierInfo *, 10> II({&Ctx.Idents.get(IIs)...});
+  SmallVector<const IdentifierInfo *, 10> II({&Ctx.Idents.get(IIs)...});
 
   return Ctx.Selectors.getSelector(II.size(), &II[0]);
 }

diff  --git a/clang/include/clang/Basic/IdentifierTable.h b/clang/include/clang/Basic/IdentifierTable.h
index a091639bfa2542..a893e6f4d3d39d 100644
--- a/clang/include/clang/Basic/IdentifierTable.h
+++ b/clang/include/clang/Basic/IdentifierTable.h
@@ -913,12 +913,13 @@ class alignas(IdentifierInfoAlignment) MultiKeywordSelector
 
 public:
   // Constructor for keyword selectors.
-  MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV)
+  MultiKeywordSelector(unsigned nKeys, const IdentifierInfo **IIV)
       : DeclarationNameExtra(nKeys) {
     assert((nKeys > 1) && "not a multi-keyword selector");
 
     // Fill in the trailing keyword array.
-    IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this + 1);
+    const IdentifierInfo **KeyInfo =
+        reinterpret_cast<const IdentifierInfo **>(this + 1);
     for (unsigned i = 0; i != nKeys; ++i)
       KeyInfo[i] = IIV[i];
   }
@@ -928,7 +929,7 @@ class alignas(IdentifierInfoAlignment) MultiKeywordSelector
 
   using DeclarationNameExtra::getNumArgs;
 
-  using keyword_iterator = IdentifierInfo *const *;
+  using keyword_iterator = const IdentifierInfo *const *;
 
   keyword_iterator keyword_begin() const {
     return reinterpret_cast<keyword_iterator>(this + 1);
@@ -938,7 +939,7 @@ class alignas(IdentifierInfoAlignment) MultiKeywordSelector
     return keyword_begin() + getNumArgs();
   }
 
-  IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
+  const IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
     return keyword_begin()[i];
   }
@@ -991,10 +992,10 @@ class Selector {
   /// Do not reorder or add any arguments to this template
   /// without thoroughly understanding how tightly coupled these classes are.
   llvm::PointerIntPair<
-      llvm::PointerUnion<IdentifierInfo *, MultiKeywordSelector *>, 2>
+      llvm::PointerUnion<const IdentifierInfo *, MultiKeywordSelector *>, 2>
       InfoPtr;
 
-  Selector(IdentifierInfo *II, unsigned nArgs) {
+  Selector(const IdentifierInfo *II, unsigned nArgs) {
     assert(nArgs < 2 && "nArgs not equal to 0/1");
     InfoPtr.setPointerAndInt(II, nArgs + 1);
   }
@@ -1006,8 +1007,8 @@ class Selector {
     InfoPtr.setPointerAndInt(SI, MultiArg & 0b11);
   }
 
-  IdentifierInfo *getAsIdentifierInfo() const {
-    return InfoPtr.getPointer().dyn_cast<IdentifierInfo *>();
+  const IdentifierInfo *getAsIdentifierInfo() const {
+    return InfoPtr.getPointer().dyn_cast<const IdentifierInfo *>();
   }
 
   MultiKeywordSelector *getMultiKeywordSelector() const {
@@ -1075,7 +1076,7 @@ class Selector {
   ///
   /// \returns the uniqued identifier for this slot, or NULL if this slot has
   /// no corresponding identifier.
-  IdentifierInfo *getIdentifierInfoForSlot(unsigned argIndex) const;
+  const IdentifierInfo *getIdentifierInfoForSlot(unsigned argIndex) const;
 
   /// Retrieve the name at a given position in the selector.
   ///
@@ -1132,13 +1133,13 @@ class SelectorTable {
   ///
   /// \p NumArgs indicates whether this is a no argument selector "foo", a
   /// single argument selector "foo:" or multi-argument "foo:bar:".
-  Selector getSelector(unsigned NumArgs, IdentifierInfo **IIV);
+  Selector getSelector(unsigned NumArgs, const IdentifierInfo **IIV);
 
-  Selector getUnarySelector(IdentifierInfo *ID) {
+  Selector getUnarySelector(const IdentifierInfo *ID) {
     return Selector(ID, 1);
   }
 
-  Selector getNullarySelector(IdentifierInfo *ID) {
+  Selector getNullarySelector(const IdentifierInfo *ID) {
     return Selector(ID, 0);
   }
 

diff  --git a/clang/include/clang/Lex/ExternalPreprocessorSource.h b/clang/include/clang/Lex/ExternalPreprocessorSource.h
index 685941b66bd8bf..6775841860373c 100644
--- a/clang/include/clang/Lex/ExternalPreprocessorSource.h
+++ b/clang/include/clang/Lex/ExternalPreprocessorSource.h
@@ -31,7 +31,7 @@ class ExternalPreprocessorSource {
   virtual void ReadDefinedMacros() = 0;
 
   /// Update an out-of-date identifier.
-  virtual void updateOutOfDateIdentifier(IdentifierInfo &II) = 0;
+  virtual void updateOutOfDateIdentifier(const IdentifierInfo &II) = 0;
 
   /// Return the identifier associated with the given ID number.
   ///

diff  --git a/clang/include/clang/Lex/MacroInfo.h b/clang/include/clang/Lex/MacroInfo.h
index 1237fc62eb6cf3..19a706216d5093 100644
--- a/clang/include/clang/Lex/MacroInfo.h
+++ b/clang/include/clang/Lex/MacroInfo.h
@@ -515,7 +515,7 @@ class ModuleMacro : public llvm::FoldingSetNode {
   friend class Preprocessor;
 
   /// The name defined by the macro.
-  IdentifierInfo *II;
+  const IdentifierInfo *II;
 
   /// The body of the #define, or nullptr if this is a #undef.
   MacroInfo *Macro;
@@ -529,7 +529,7 @@ class ModuleMacro : public llvm::FoldingSetNode {
   /// The number of modules whose macros are directly overridden by this one.
   unsigned NumOverrides;
 
-  ModuleMacro(Module *OwningModule, IdentifierInfo *II, MacroInfo *Macro,
+  ModuleMacro(Module *OwningModule, const IdentifierInfo *II, MacroInfo *Macro,
               ArrayRef<ModuleMacro *> Overrides)
       : II(II), Macro(Macro), OwningModule(OwningModule),
         NumOverrides(Overrides.size()) {
@@ -539,7 +539,7 @@ class ModuleMacro : public llvm::FoldingSetNode {
 
 public:
   static ModuleMacro *create(Preprocessor &PP, Module *OwningModule,
-                             IdentifierInfo *II, MacroInfo *Macro,
+                             const IdentifierInfo *II, MacroInfo *Macro,
                              ArrayRef<ModuleMacro *> Overrides);
 
   void Profile(llvm::FoldingSetNodeID &ID) const {
@@ -553,7 +553,7 @@ class ModuleMacro : public llvm::FoldingSetNode {
   }
 
   /// Get the name of the macro.
-  IdentifierInfo *getName() const { return II; }
+  const IdentifierInfo *getName() const { return II; }
 
   /// Get the ID of the module that exports this macro.
   Module *getOwningModule() const { return OwningModule; }

diff  --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
index 0836b7d439bb04..e89b4a2c5230e7 100644
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -836,7 +836,7 @@ class Preprocessor {
     ModuleMacroInfo *getModuleInfo(Preprocessor &PP,
                                    const IdentifierInfo *II) const {
       if (II->isOutOfDate())
-        PP.updateOutOfDateIdentifier(const_cast<IdentifierInfo&>(*II));
+        PP.updateOutOfDateIdentifier(*II);
       // FIXME: Find a spare bit on IdentifierInfo and store a
       //        HasModuleMacros flag.
       if (!II->hasMacroDefinition() ||
@@ -1162,7 +1162,7 @@ class Preprocessor {
   /// skipped.
   llvm::DenseMap<const char *, unsigned> RecordedSkippedRanges;
 
-  void updateOutOfDateIdentifier(IdentifierInfo &II) const;
+  void updateOutOfDateIdentifier(const IdentifierInfo &II) const;
 
 public:
   Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,
@@ -1432,14 +1432,15 @@ class Preprocessor {
                                MacroDirective *MD);
 
   /// Register an exported macro for a module and identifier.
-  ModuleMacro *addModuleMacro(Module *Mod, IdentifierInfo *II, MacroInfo *Macro,
+  ModuleMacro *addModuleMacro(Module *Mod, const IdentifierInfo *II,
+                              MacroInfo *Macro,
                               ArrayRef<ModuleMacro *> Overrides, bool &IsNew);
   ModuleMacro *getModuleMacro(Module *Mod, const IdentifierInfo *II);
 
   /// Get the list of leaf (non-overridden) module macros for a name.
   ArrayRef<ModuleMacro*> getLeafModuleMacros(const IdentifierInfo *II) const {
     if (II->isOutOfDate())
-      updateOutOfDateIdentifier(const_cast<IdentifierInfo&>(*II));
+      updateOutOfDateIdentifier(*II);
     auto I = LeafModuleMacros.find(II);
     if (I != LeafModuleMacros.end())
       return I->second;

diff  --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 8bc929b1dfe4bb..3a055c10ffb387 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -329,7 +329,7 @@ class Parser : public CodeCompletionHandler {
   };
 
   /// Identifiers which have been declared within a tentative parse.
-  SmallVector<IdentifierInfo *, 8> TentativelyDeclaredIdentifiers;
+  SmallVector<const IdentifierInfo *, 8> TentativelyDeclaredIdentifiers;
 
   /// Tracker for '<' tokens that might have been intended to be treated as an
   /// angle bracket instead of a less-than comparison.
@@ -1927,15 +1927,11 @@ class Parser : public CodeCompletionHandler {
                                   bool EnteringContext, IdentifierInfo &II,
                                   CXXScopeSpec &SS);
 
-  bool ParseOptionalCXXScopeSpecifier(CXXScopeSpec &SS,
-                                      ParsedType ObjectType,
-                                      bool ObjectHasErrors,
-                                      bool EnteringContext,
-                                      bool *MayBePseudoDestructor = nullptr,
-                                      bool IsTypename = false,
-                                      IdentifierInfo **LastII = nullptr,
-                                      bool OnlyNamespace = false,
-                                      bool InUsingDeclaration = false);
+  bool ParseOptionalCXXScopeSpecifier(
+      CXXScopeSpec &SS, ParsedType ObjectType, bool ObjectHasErrors,
+      bool EnteringContext, bool *MayBePseudoDestructor = nullptr,
+      bool IsTypename = false, const IdentifierInfo **LastII = nullptr,
+      bool OnlyNamespace = false, bool InUsingDeclaration = false);
 
   //===--------------------------------------------------------------------===//
   // C++11 5.1.2: Lambda expressions

diff  --git a/clang/include/clang/Sema/CodeCompleteConsumer.h b/clang/include/clang/Sema/CodeCompleteConsumer.h
index a2028e40f83d54..0924dc27af82b5 100644
--- a/clang/include/clang/Sema/CodeCompleteConsumer.h
+++ b/clang/include/clang/Sema/CodeCompleteConsumer.h
@@ -362,7 +362,7 @@ class CodeCompletionContext {
   QualType BaseType;
 
   /// The identifiers for Objective-C selector parts.
-  ArrayRef<IdentifierInfo *> SelIdents;
+  ArrayRef<const IdentifierInfo *> SelIdents;
 
   /// The scope specifier that comes before the completion token e.g.
   /// "a::b::"
@@ -378,8 +378,9 @@ class CodeCompletionContext {
       : CCKind(CCKind), IsUsingDeclaration(false), SelIdents(std::nullopt) {}
 
   /// Construct a new code-completion context of the given kind.
-  CodeCompletionContext(Kind CCKind, QualType T,
-                        ArrayRef<IdentifierInfo *> SelIdents = std::nullopt)
+  CodeCompletionContext(
+      Kind CCKind, QualType T,
+      ArrayRef<const IdentifierInfo *> SelIdents = std::nullopt)
       : CCKind(CCKind), IsUsingDeclaration(false), SelIdents(SelIdents) {
     if (CCKind == CCC_DotMemberAccess || CCKind == CCC_ArrowMemberAccess ||
         CCKind == CCC_ObjCPropertyAccess || CCKind == CCC_ObjCClassMessage ||
@@ -406,7 +407,7 @@ class CodeCompletionContext {
   QualType getBaseType() const { return BaseType; }
 
   /// Retrieve the Objective-C selector identifiers.
-  ArrayRef<IdentifierInfo *> getSelIdents() const { return SelIdents; }
+  ArrayRef<const IdentifierInfo *> getSelIdents() const { return SelIdents; }
 
   /// Determines whether we want C++ constructors as results within this
   /// context.

diff  --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index a176159707486c..c9eecdafe62c7c 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -1049,7 +1049,7 @@ class UnqualifiedId {
   union {
     /// When Kind == IK_Identifier, the parsed identifier, or when
     /// Kind == IK_UserLiteralId, the identifier suffix.
-    IdentifierInfo *Identifier;
+    const IdentifierInfo *Identifier;
 
     /// When Kind == IK_OperatorFunctionId, the overloaded operator
     /// that we parsed.
@@ -1111,7 +1111,7 @@ class UnqualifiedId {
   /// \param IdLoc the location of the parsed identifier.
   void setIdentifier(const IdentifierInfo *Id, SourceLocation IdLoc) {
     Kind = UnqualifiedIdKind::IK_Identifier;
-    Identifier = const_cast<IdentifierInfo *>(Id);
+    Identifier = Id;
     StartLocation = EndLocation = IdLoc;
   }
 
@@ -1154,9 +1154,9 @@ class UnqualifiedId {
   ///
   /// \param IdLoc the location of the identifier.
   void setLiteralOperatorId(const IdentifierInfo *Id, SourceLocation OpLoc,
-                              SourceLocation IdLoc) {
+                            SourceLocation IdLoc) {
     Kind = UnqualifiedIdKind::IK_LiteralOperatorId;
-    Identifier = const_cast<IdentifierInfo *>(Id);
+    Identifier = Id;
     StartLocation = OpLoc;
     EndLocation = IdLoc;
   }
@@ -1225,7 +1225,7 @@ class UnqualifiedId {
   /// \param Id the identifier.
   void setImplicitSelfParam(const IdentifierInfo *Id) {
     Kind = UnqualifiedIdKind::IK_ImplicitSelfParam;
-    Identifier = const_cast<IdentifierInfo *>(Id);
+    Identifier = Id;
     StartLocation = EndLocation = SourceLocation();
   }
 
@@ -1327,7 +1327,7 @@ struct DeclaratorChunk {
   /// Parameter type lists will have type info (if the actions module provides
   /// it), but may have null identifier info: e.g. for 'void foo(int X, int)'.
   struct ParamInfo {
-    IdentifierInfo *Ident;
+    const IdentifierInfo *Ident;
     SourceLocation IdentLoc;
     Decl *Param;
 
@@ -1339,11 +1339,10 @@ struct DeclaratorChunk {
     std::unique_ptr<CachedTokens> DefaultArgTokens;
 
     ParamInfo() = default;
-    ParamInfo(IdentifierInfo *ident, SourceLocation iloc,
-              Decl *param,
+    ParamInfo(const IdentifierInfo *ident, SourceLocation iloc, Decl *param,
               std::unique_ptr<CachedTokens> DefArgTokens = nullptr)
-      : Ident(ident), IdentLoc(iloc), Param(param),
-        DefaultArgTokens(std::move(DefArgTokens)) {}
+        : Ident(ident), IdentLoc(iloc), Param(param),
+          DefaultArgTokens(std::move(DefArgTokens)) {}
   };
 
   struct TypeAndRange {
@@ -2326,7 +2325,7 @@ class Declarator {
     return BindingGroup.isSet();
   }
 
-  IdentifierInfo *getIdentifier() const {
+  const IdentifierInfo *getIdentifier() const {
     if (Name.getKind() == UnqualifiedIdKind::IK_Identifier)
       return Name.Identifier;
 
@@ -2335,7 +2334,7 @@ class Declarator {
   SourceLocation getIdentifierLoc() const { return Name.StartLocation; }
 
   /// Set the name of this declarator to be the given identifier.
-  void SetIdentifier(IdentifierInfo *Id, SourceLocation IdLoc) {
+  void SetIdentifier(const IdentifierInfo *Id, SourceLocation IdLoc) {
     Name.setIdentifier(Id, IdLoc);
   }
 

diff  --git a/clang/include/clang/Sema/ParsedTemplate.h b/clang/include/clang/Sema/ParsedTemplate.h
index 65182d57246ae7..ac4dbbf294caf2 100644
--- a/clang/include/clang/Sema/ParsedTemplate.h
+++ b/clang/include/clang/Sema/ParsedTemplate.h
@@ -159,7 +159,7 @@ namespace clang {
     SourceLocation TemplateNameLoc;
 
     /// FIXME: Temporarily stores the name of a specialization
-    IdentifierInfo *Name;
+    const IdentifierInfo *Name;
 
     /// FIXME: Temporarily stores the overloaded operator kind.
     OverloadedOperatorKind Operator;
@@ -197,7 +197,7 @@ namespace clang {
     /// appends it to List.
     static TemplateIdAnnotation *
     Create(SourceLocation TemplateKWLoc, SourceLocation TemplateNameLoc,
-           IdentifierInfo *Name, OverloadedOperatorKind OperatorKind,
+           const IdentifierInfo *Name, OverloadedOperatorKind OperatorKind,
            ParsedTemplateTy OpaqueTemplateName, TemplateNameKind TemplateKind,
            SourceLocation LAngleLoc, SourceLocation RAngleLoc,
            ArrayRef<ParsedTemplateArgument> TemplateArgs, bool ArgsInvalid,
@@ -236,7 +236,8 @@ namespace clang {
     TemplateIdAnnotation(const TemplateIdAnnotation &) = delete;
 
     TemplateIdAnnotation(SourceLocation TemplateKWLoc,
-                         SourceLocation TemplateNameLoc, IdentifierInfo *Name,
+                         SourceLocation TemplateNameLoc,
+                         const IdentifierInfo *Name,
                          OverloadedOperatorKind OperatorKind,
                          ParsedTemplateTy OpaqueTemplateName,
                          TemplateNameKind TemplateKind,

diff  --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index e3e255a0dd76f8..0ee4f3c8e127f6 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -568,7 +568,7 @@ class Sema final : public SemaBase {
 
   /// Invent a new identifier for parameters of abbreviated templates.
   IdentifierInfo *
-  InventAbbreviatedTemplateParameterTypeName(IdentifierInfo *ParamName,
+  InventAbbreviatedTemplateParameterTypeName(const IdentifierInfo *ParamName,
                                              unsigned Index);
 
   void emitAndClearUnusedLocalTypedefWarnings();
@@ -2958,9 +2958,9 @@ class Sema final : public SemaBase {
                                                   SourceLocation NameLoc,
                                                   TypeSourceInfo *TSInfo);
   ParmVarDecl *CheckParameter(DeclContext *DC, SourceLocation StartLoc,
-                              SourceLocation NameLoc, IdentifierInfo *Name,
-                              QualType T, TypeSourceInfo *TSInfo,
-                              StorageClass SC);
+                              SourceLocation NameLoc,
+                              const IdentifierInfo *Name, QualType T,
+                              TypeSourceInfo *TSInfo, StorageClass SC);
 
   // Contexts where using non-trivial C union types can be disallowed. This is
   // passed to err_non_trivial_c_union_in_invalid_context.
@@ -3365,7 +3365,7 @@ class Sema final : public SemaBase {
   /// variable.
   void DiagnoseUnusedButSetDecl(const VarDecl *VD, DiagReceiverTy DiagReceiver);
 
-  ObjCInterfaceDecl *getObjCInterfaceDecl(IdentifierInfo *&Id,
+  ObjCInterfaceDecl *getObjCInterfaceDecl(const IdentifierInfo *&Id,
                                           SourceLocation IdLoc,
                                           bool TypoCorrection = false);
 
@@ -3442,8 +3442,9 @@ class Sema final : public SemaBase {
   /// VerifyBitField - verifies that a bit field expression is an ICE and has
   /// the correct width, and that the field type is valid.
   /// Returns false on success.
-  ExprResult VerifyBitField(SourceLocation FieldLoc, IdentifierInfo *FieldName,
-                            QualType FieldTy, bool IsMsStruct, Expr *BitWidth);
+  ExprResult VerifyBitField(SourceLocation FieldLoc,
+                            const IdentifierInfo *FieldName, QualType FieldTy,
+                            bool IsMsStruct, Expr *BitWidth);
 
   /// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
   /// enum. If AllowMask is true, then we also allow the complement of a valid
@@ -4638,7 +4639,8 @@ class Sema final : public SemaBase {
 
   VarDecl *BuildExceptionDeclaration(Scope *S, TypeSourceInfo *TInfo,
                                      SourceLocation StartLoc,
-                                     SourceLocation IdLoc, IdentifierInfo *Id);
+                                     SourceLocation IdLoc,
+                                     const IdentifierInfo *Id);
 
   Decl *ActOnExceptionDeclarator(Scope *S, Declarator &D);
 
@@ -6555,12 +6557,12 @@ class Sema final : public SemaBase {
 
   ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
                                           SourceLocation NameLoc,
-                                          IdentifierInfo &Name);
+                                          const IdentifierInfo &Name);
 
-  ParsedType getConstructorName(IdentifierInfo &II, SourceLocation NameLoc,
-                                Scope *S, CXXScopeSpec &SS,
-                                bool EnteringContext);
-  ParsedType getDestructorName(IdentifierInfo &II, SourceLocation NameLoc,
+  ParsedType getConstructorName(const IdentifierInfo &II,
+                                SourceLocation NameLoc, Scope *S,
+                                CXXScopeSpec &SS, bool EnteringContext);
+  ParsedType getDestructorName(const IdentifierInfo &II, SourceLocation NameLoc,
                                Scope *S, CXXScopeSpec &SS,
                                ParsedType ObjectType, bool EnteringContext);
 
@@ -6960,7 +6962,7 @@ class Sema final : public SemaBase {
   concepts::Requirement *ActOnTypeRequirement(SourceLocation TypenameKWLoc,
                                               CXXScopeSpec &SS,
                                               SourceLocation NameLoc,
-                                              IdentifierInfo *TypeName,
+                                              const IdentifierInfo *TypeName,
                                               TemplateIdAnnotation *TemplateId);
   concepts::Requirement *ActOnCompoundRequirement(Expr *E,
                                                   SourceLocation NoexceptLoc);
@@ -9116,7 +9118,7 @@ class Sema final : public SemaBase {
 
   TypeResult
   ActOnTemplateIdType(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
-                      TemplateTy Template, IdentifierInfo *TemplateII,
+                      TemplateTy Template, const IdentifierInfo *TemplateII,
                       SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
                       ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
                       bool IsCtorOrDtorName = false, bool IsClassName = false,
@@ -9457,7 +9459,7 @@ class Sema final : public SemaBase {
   TypeResult
   ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
                     const CXXScopeSpec &SS, SourceLocation TemplateLoc,
-                    TemplateTy TemplateName, IdentifierInfo *TemplateII,
+                    TemplateTy TemplateName, const IdentifierInfo *TemplateII,
                     SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
                     ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc);
 
@@ -9535,14 +9537,15 @@ class Sema final : public SemaBase {
 
   Decl *ActOnConceptDefinition(Scope *S,
                                MultiTemplateParamsArg TemplateParameterLists,
-                               IdentifierInfo *Name, SourceLocation NameLoc,
-                               Expr *ConstraintExpr);
+                               const IdentifierInfo *Name,
+                               SourceLocation NameLoc, Expr *ConstraintExpr);
 
   void CheckConceptRedefinition(ConceptDecl *NewDecl, LookupResult &Previous,
                                 bool &AddToScope);
 
   TypeResult ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
-                               const CXXScopeSpec &SS, IdentifierInfo *Name,
+                               const CXXScopeSpec &SS,
+                               const IdentifierInfo *Name,
                                SourceLocation TagLoc, SourceLocation NameLoc);
 
   void MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
@@ -11988,22 +11991,22 @@ class Sema final : public SemaBase {
       SkipBodyInfo *SkipBody);
 
   ObjCCategoryDecl *ActOnStartCategoryInterface(
-      SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
+      SourceLocation AtInterfaceLoc, const IdentifierInfo *ClassName,
       SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
-      IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
+      const IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
       Decl *const *ProtoRefs, unsigned NumProtoRefs,
       const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
       const ParsedAttributesView &AttrList);
 
   ObjCImplementationDecl *ActOnStartClassImplementation(
-      SourceLocation AtClassImplLoc, IdentifierInfo *ClassName,
-      SourceLocation ClassLoc, IdentifierInfo *SuperClassname,
+      SourceLocation AtClassImplLoc, const IdentifierInfo *ClassName,
+      SourceLocation ClassLoc, const IdentifierInfo *SuperClassname,
       SourceLocation SuperClassLoc, const ParsedAttributesView &AttrList);
 
   ObjCCategoryImplDecl *ActOnStartCategoryImplementation(
-      SourceLocation AtCatImplLoc, IdentifierInfo *ClassName,
-      SourceLocation ClassLoc, IdentifierInfo *CatName, SourceLocation CatLoc,
-      const ParsedAttributesView &AttrList);
+      SourceLocation AtCatImplLoc, const IdentifierInfo *ClassName,
+      SourceLocation ClassLoc, const IdentifierInfo *CatName,
+      SourceLocation CatLoc, const ParsedAttributesView &AttrList);
 
   DeclGroupPtrTy ActOnFinishObjCImplementation(Decl *ObjCImpDecl,
                                                ArrayRef<Decl *> Decls);
@@ -12186,11 +12189,13 @@ class Sema final : public SemaBase {
   bool CheckObjCDeclScope(Decl *D);
 
   void ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
-                 IdentifierInfo *ClassName, SmallVectorImpl<Decl *> &Decls);
+                 const IdentifierInfo *ClassName,
+                 SmallVectorImpl<Decl *> &Decls);
 
   VarDecl *BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType ExceptionType,
                                   SourceLocation StartLoc, SourceLocation IdLoc,
-                                  IdentifierInfo *Id, bool Invalid = false);
+                                  const IdentifierInfo *Id,
+                                  bool Invalid = false);
 
   Decl *ActOnObjCExceptionDecl(Scope *S, Declarator &D);
 
@@ -12307,8 +12312,8 @@ class Sema final : public SemaBase {
                                        SourceLocation SuperLoc,
                                        QualType SuperType, bool Super);
 
-  ExprResult ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
-                                       IdentifierInfo &propertyName,
+  ExprResult ActOnClassPropertyRefExpr(const IdentifierInfo &receiverName,
+                                       const IdentifierInfo &propertyName,
                                        SourceLocation receiverNameLoc,
                                        SourceLocation propertyNameLoc);
 
@@ -12783,18 +12788,18 @@ class Sema final : public SemaBase {
                                    bool IsParameter);
   void CodeCompleteObjCMessageReceiver(Scope *S);
   void CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
-                                    ArrayRef<IdentifierInfo *> SelIdents,
+                                    ArrayRef<const IdentifierInfo *> SelIdents,
                                     bool AtArgumentExpression);
   void CodeCompleteObjCClassMessage(Scope *S, ParsedType Receiver,
-                                    ArrayRef<IdentifierInfo *> SelIdents,
+                                    ArrayRef<const IdentifierInfo *> SelIdents,
                                     bool AtArgumentExpression,
                                     bool IsSuper = false);
-  void CodeCompleteObjCInstanceMessage(Scope *S, Expr *Receiver,
-                                       ArrayRef<IdentifierInfo *> SelIdents,
-                                       bool AtArgumentExpression,
-                                       ObjCInterfaceDecl *Super = nullptr);
+  void CodeCompleteObjCInstanceMessage(
+      Scope *S, Expr *Receiver, ArrayRef<const IdentifierInfo *> SelIdents,
+      bool AtArgumentExpression, ObjCInterfaceDecl *Super = nullptr);
   void CodeCompleteObjCForCollection(Scope *S, DeclGroupPtrTy IterationVar);
-  void CodeCompleteObjCSelector(Scope *S, ArrayRef<IdentifierInfo *> SelIdents);
+  void CodeCompleteObjCSelector(Scope *S,
+                                ArrayRef<const IdentifierInfo *> SelIdents);
   void
   CodeCompleteObjCProtocolReferences(ArrayRef<IdentifierLocPair> Protocols);
   void CodeCompleteObjCProtocolDecl(Scope *S);
@@ -12814,11 +12819,11 @@ class Sema final : public SemaBase {
   void CodeCompleteObjCMethodDecl(Scope *S,
                                   std::optional<bool> IsInstanceMethod,
                                   ParsedType ReturnType);
-  void CodeCompleteObjCMethodDeclSelector(Scope *S, bool IsInstanceMethod,
-                                          bool AtParameterName,
-                                          ParsedType ReturnType,
-                                          ArrayRef<IdentifierInfo *> SelIdents);
-  void CodeCompleteObjCClassPropertyRefExpr(Scope *S, IdentifierInfo &ClassName,
+  void CodeCompleteObjCMethodDeclSelector(
+      Scope *S, bool IsInstanceMethod, bool AtParameterName,
+      ParsedType ReturnType, ArrayRef<const IdentifierInfo *> SelIdents);
+  void CodeCompleteObjCClassPropertyRefExpr(Scope *S,
+                                            const IdentifierInfo &ClassName,
                                             SourceLocation ClassNameLoc,
                                             bool IsBaseExprStatement);
   void CodeCompletePreprocessorDirective(bool InConditional);

diff  --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
index 1911252b34cd1c..5fd55a519c6b0f 100644
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -1082,12 +1082,12 @@ class ASTReader
 
   /// The set of lookup results that we have faked in order to support
   /// merging of partially deserialized decls but that we have not yet removed.
-  llvm::SmallMapVector<IdentifierInfo *, SmallVector<NamedDecl*, 2>, 16>
-    PendingFakeLookupResults;
+  llvm::SmallMapVector<const IdentifierInfo *, SmallVector<NamedDecl *, 2>, 16>
+      PendingFakeLookupResults;
 
   /// The generation number of each identifier, which keeps track of
   /// the last time we loaded information about this identifier.
-  llvm::DenseMap<IdentifierInfo *, unsigned> IdentifierGeneration;
+  llvm::DenseMap<const IdentifierInfo *, unsigned> IdentifierGeneration;
 
   /// Contains declarations and definitions that could be
   /// "interesting" to the ASTConsumer, when we get that AST consumer.
@@ -2330,10 +2330,10 @@ class ASTReader
   void ReadDefinedMacros() override;
 
   /// Update an out-of-date identifier.
-  void updateOutOfDateIdentifier(IdentifierInfo &II) override;
+  void updateOutOfDateIdentifier(const IdentifierInfo &II) override;
 
   /// Note that this identifier is up-to-date.
-  void markIdentifierUpToDate(IdentifierInfo *II);
+  void markIdentifierUpToDate(const IdentifierInfo *II);
 
   /// Load all external visible decls in the given DeclContext.
   void completeVisibleDeclsMap(const DeclContext *DC) override;

diff  --git a/clang/lib/ARCMigrate/ObjCMT.cpp b/clang/lib/ARCMigrate/ObjCMT.cpp
index 0786c81516b2d1..b9dcfb8951b3e1 100644
--- a/clang/lib/ARCMigrate/ObjCMT.cpp
+++ b/clang/lib/ARCMigrate/ObjCMT.cpp
@@ -1144,7 +1144,7 @@ static bool IsValidIdentifier(ASTContext &Ctx,
     return false;
   std::string NameString = Name;
   NameString[0] = toLowercase(NameString[0]);
-  IdentifierInfo *II = &Ctx.Idents.get(NameString);
+  const IdentifierInfo *II = &Ctx.Idents.get(NameString);
   return II->getTokenID() ==  tok::identifier;
 }
 
@@ -1166,7 +1166,7 @@ bool ObjCMigrateASTConsumer::migrateProperty(ASTContext &Ctx,
   if (OIT_Family != OIT_None)
     return false;
 
-  IdentifierInfo *getterName = GetterSelector.getIdentifierInfoForSlot(0);
+  const IdentifierInfo *getterName = GetterSelector.getIdentifierInfoForSlot(0);
   Selector SetterSelector =
   SelectorTable::constructSetterSelector(PP.getIdentifierTable(),
                                          PP.getSelectorTable(),
@@ -1311,7 +1311,8 @@ void ObjCMigrateASTConsumer::migrateFactoryMethod(ASTContext &Ctx,
   std::string StringLoweredClassName = LoweredClassName.lower();
   LoweredClassName = StringLoweredClassName;
 
-  IdentifierInfo *MethodIdName = OM->getSelector().getIdentifierInfoForSlot(0);
+  const IdentifierInfo *MethodIdName =
+      OM->getSelector().getIdentifierInfoForSlot(0);
   // Handle method with no name at its first selector slot; e.g. + (id):(int)x.
   if (!MethodIdName)
     return;

diff  --git a/clang/lib/ARCMigrate/TransAPIUses.cpp b/clang/lib/ARCMigrate/TransAPIUses.cpp
index 638850dcf9ecc7..8f5d4f4bde06ca 100644
--- a/clang/lib/ARCMigrate/TransAPIUses.cpp
+++ b/clang/lib/ARCMigrate/TransAPIUses.cpp
@@ -41,7 +41,7 @@ class APIChecker : public RecursiveASTVisitor<APIChecker> {
     getReturnValueSel = sels.getUnarySelector(&ids.get("getReturnValue"));
     setReturnValueSel = sels.getUnarySelector(&ids.get("setReturnValue"));
 
-    IdentifierInfo *selIds[2];
+    const IdentifierInfo *selIds[2];
     selIds[0] = &ids.get("getArgument");
     selIds[1] = &ids.get("atIndex");
     getArgumentSel = sels.getSelector(2, selIds);

diff  --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index f7f55dc4e7a9f4..2fa6aedca4c6ab 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -6929,16 +6929,13 @@ ASTContext::getCanonicalNestedNameSpecifier(NestedNameSpecifier *NNS) const {
     //   typedef typename T::type T1;
     //   typedef typename T1::type T2;
     if (const auto *DNT = T->getAs<DependentNameType>())
-      return NestedNameSpecifier::Create(
-          *this, DNT->getQualifier(),
-          const_cast<IdentifierInfo *>(DNT->getIdentifier()));
+      return NestedNameSpecifier::Create(*this, DNT->getQualifier(),
+                                         DNT->getIdentifier());
     if (const auto *DTST = T->getAs<DependentTemplateSpecializationType>())
-      return NestedNameSpecifier::Create(*this, DTST->getQualifier(), true,
-                                         const_cast<Type *>(T));
+      return NestedNameSpecifier::Create(*this, DTST->getQualifier(), true, T);
 
     // TODO: Set 'Template' parameter to true for other template types.
-    return NestedNameSpecifier::Create(*this, nullptr, false,
-                                       const_cast<Type *>(T));
+    return NestedNameSpecifier::Create(*this, nullptr, false, T);
   }
 
   case NestedNameSpecifier::Global:

diff  --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 45d4c9600537be..d5ec5ee4091562 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -8383,8 +8383,8 @@ ASTNodeImporter::VisitCXXPseudoDestructorExpr(CXXPseudoDestructorExpr *E) {
     return std::move(Err);
 
   PseudoDestructorTypeStorage Storage;
-  if (IdentifierInfo *FromII = E->getDestroyedTypeIdentifier()) {
-    IdentifierInfo *ToII = Importer.Import(FromII);
+  if (const IdentifierInfo *FromII = E->getDestroyedTypeIdentifier()) {
+    const IdentifierInfo *ToII = Importer.Import(FromII);
     ExpectedSLoc ToDestroyedTypeLocOrErr = import(E->getDestroyedTypeLoc());
     if (!ToDestroyedTypeLocOrErr)
       return ToDestroyedTypeLocOrErr.takeError();
@@ -10194,7 +10194,7 @@ Expected<Selector> ASTImporter::Import(Selector FromSel) {
   if (FromSel.isNull())
     return Selector{};
 
-  SmallVector<IdentifierInfo *, 4> Idents;
+  SmallVector<const IdentifierInfo *, 4> Idents;
   Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(0)));
   for (unsigned I = 1, N = FromSel.getNumArgs(); I < N; ++I)
     Idents.push_back(Import(FromSel.getIdentifierInfoForSlot(I)));

diff  --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 131f82985e903b..60e0a3aecf6c8e 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2913,10 +2913,10 @@ VarDecl::setInstantiationOfStaticDataMember(VarDecl *VD,
 //===----------------------------------------------------------------------===//
 
 ParmVarDecl *ParmVarDecl::Create(ASTContext &C, DeclContext *DC,
-                                 SourceLocation StartLoc,
-                                 SourceLocation IdLoc, IdentifierInfo *Id,
-                                 QualType T, TypeSourceInfo *TInfo,
-                                 StorageClass S, Expr *DefArg) {
+                                 SourceLocation StartLoc, SourceLocation IdLoc,
+                                 const IdentifierInfo *Id, QualType T,
+                                 TypeSourceInfo *TInfo, StorageClass S,
+                                 Expr *DefArg) {
   return new (C, DC) ParmVarDecl(ParmVar, C, DC, StartLoc, IdLoc, Id, T, TInfo,
                                  S, DefArg);
 }
@@ -4511,7 +4511,7 @@ unsigned FunctionDecl::getODRHash() {
 
 FieldDecl *FieldDecl::Create(const ASTContext &C, DeclContext *DC,
                              SourceLocation StartLoc, SourceLocation IdLoc,
-                             IdentifierInfo *Id, QualType T,
+                             const IdentifierInfo *Id, QualType T,
                              TypeSourceInfo *TInfo, Expr *BW, bool Mutable,
                              InClassInitStyle InitStyle) {
   return new (C, DC) FieldDecl(Decl::Field, DC, StartLoc, IdLoc, Id, T, TInfo,
@@ -5438,7 +5438,7 @@ IndirectFieldDecl::IndirectFieldDecl(ASTContext &C, DeclContext *DC,
 
 IndirectFieldDecl *
 IndirectFieldDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
-                          IdentifierInfo *Id, QualType T,
+                          const IdentifierInfo *Id, QualType T,
                           llvm::MutableArrayRef<NamedDecl *> CH) {
   return new (C, DC) IndirectFieldDecl(C, DC, L, Id, T, CH);
 }
@@ -5461,7 +5461,8 @@ void TypeDecl::anchor() {}
 
 TypedefDecl *TypedefDecl::Create(ASTContext &C, DeclContext *DC,
                                  SourceLocation StartLoc, SourceLocation IdLoc,
-                                 IdentifierInfo *Id, TypeSourceInfo *TInfo) {
+                                 const IdentifierInfo *Id,
+                                 TypeSourceInfo *TInfo) {
   return new (C, DC) TypedefDecl(C, DC, StartLoc, IdLoc, Id, TInfo);
 }
 
@@ -5511,7 +5512,8 @@ TypedefDecl *TypedefDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
 
 TypeAliasDecl *TypeAliasDecl::Create(ASTContext &C, DeclContext *DC,
                                      SourceLocation StartLoc,
-                                     SourceLocation IdLoc, IdentifierInfo *Id,
+                                     SourceLocation IdLoc,
+                                     const IdentifierInfo *Id,
                                      TypeSourceInfo *TInfo) {
   return new (C, DC) TypeAliasDecl(C, DC, StartLoc, IdLoc, Id, TInfo);
 }

diff  --git a/clang/lib/AST/DeclObjC.cpp b/clang/lib/AST/DeclObjC.cpp
index 962f503306a0f0..32c14938cd5888 100644
--- a/clang/lib/AST/DeclObjC.cpp
+++ b/clang/lib/AST/DeclObjC.cpp
@@ -66,7 +66,8 @@ void ObjCProtocolList::set(ObjCProtocolDecl* const* InList, unsigned Elts,
 //===----------------------------------------------------------------------===//
 
 ObjCContainerDecl::ObjCContainerDecl(Kind DK, DeclContext *DC,
-                                     IdentifierInfo *Id, SourceLocation nameLoc,
+                                     const IdentifierInfo *Id,
+                                     SourceLocation nameLoc,
                                      SourceLocation atStartLoc)
     : NamedDecl(DK, DC, nameLoc, Id), DeclContext(DK) {
   setAtStartLoc(atStartLoc);
@@ -378,10 +379,8 @@ SourceLocation ObjCInterfaceDecl::getSuperClassLoc() const {
 /// FindPropertyVisibleInPrimaryClass - Finds declaration of the property
 /// with name 'PropertyId' in the primary class; including those in protocols
 /// (direct or indirect) used by the primary class.
-ObjCPropertyDecl *
-ObjCInterfaceDecl::FindPropertyVisibleInPrimaryClass(
-                       IdentifierInfo *PropertyId,
-                       ObjCPropertyQueryKind QueryKind) const {
+ObjCPropertyDecl *ObjCInterfaceDecl::FindPropertyVisibleInPrimaryClass(
+    const IdentifierInfo *PropertyId, ObjCPropertyQueryKind QueryKind) const {
   // FIXME: Should make sure no callers ever do this.
   if (!hasDefinition())
     return nullptr;
@@ -1539,14 +1538,10 @@ void ObjCTypeParamList::gatherDefaultTypeArgs(
 // ObjCInterfaceDecl
 //===----------------------------------------------------------------------===//
 
-ObjCInterfaceDecl *ObjCInterfaceDecl::Create(const ASTContext &C,
-                                             DeclContext *DC,
-                                             SourceLocation atLoc,
-                                             IdentifierInfo *Id,
-                                             ObjCTypeParamList *typeParamList,
-                                             ObjCInterfaceDecl *PrevDecl,
-                                             SourceLocation ClassLoc,
-                                             bool isInternal){
+ObjCInterfaceDecl *ObjCInterfaceDecl::Create(
+    const ASTContext &C, DeclContext *DC, SourceLocation atLoc,
+    const IdentifierInfo *Id, ObjCTypeParamList *typeParamList,
+    ObjCInterfaceDecl *PrevDecl, SourceLocation ClassLoc, bool isInternal) {
   auto *Result = new (C, DC)
       ObjCInterfaceDecl(C, DC, atLoc, Id, typeParamList, ClassLoc, PrevDecl,
                         isInternal);
@@ -1564,12 +1559,10 @@ ObjCInterfaceDecl *ObjCInterfaceDecl::CreateDeserialized(const ASTContext &C,
   return Result;
 }
 
-ObjCInterfaceDecl::ObjCInterfaceDecl(const ASTContext &C, DeclContext *DC,
-                                     SourceLocation AtLoc, IdentifierInfo *Id,
-                                     ObjCTypeParamList *typeParamList,
-                                     SourceLocation CLoc,
-                                     ObjCInterfaceDecl *PrevDecl,
-                                     bool IsInternal)
+ObjCInterfaceDecl::ObjCInterfaceDecl(
+    const ASTContext &C, DeclContext *DC, SourceLocation AtLoc,
+    const IdentifierInfo *Id, ObjCTypeParamList *typeParamList,
+    SourceLocation CLoc, ObjCInterfaceDecl *PrevDecl, bool IsInternal)
     : ObjCContainerDecl(ObjCInterface, DC, Id, CLoc, AtLoc),
       redeclarable_base(C) {
   setPreviousDecl(PrevDecl);
@@ -1751,8 +1744,8 @@ ObjCIvarDecl *ObjCInterfaceDecl::all_declared_ivar_begin() {
 /// categories for this class and returns it. Name of the category is passed
 /// in 'CategoryId'. If category not found, return 0;
 ///
-ObjCCategoryDecl *
-ObjCInterfaceDecl::FindCategoryDeclaration(IdentifierInfo *CategoryId) const {
+ObjCCategoryDecl *ObjCInterfaceDecl::FindCategoryDeclaration(
+    const IdentifierInfo *CategoryId) const {
   // FIXME: Should make sure no callers ever do this.
   if (!hasDefinition())
     return nullptr;
@@ -1838,10 +1831,10 @@ void ObjCIvarDecl::anchor() {}
 
 ObjCIvarDecl *ObjCIvarDecl::Create(ASTContext &C, ObjCContainerDecl *DC,
                                    SourceLocation StartLoc,
-                                   SourceLocation IdLoc, IdentifierInfo *Id,
-                                   QualType T, TypeSourceInfo *TInfo,
-                                   AccessControl ac, Expr *BW,
-                                   bool synthesized) {
+                                   SourceLocation IdLoc,
+                                   const IdentifierInfo *Id, QualType T,
+                                   TypeSourceInfo *TInfo, AccessControl ac,
+                                   Expr *BW, bool synthesized) {
   if (DC) {
     // Ivar's can only appear in interfaces, implementations (via synthesized
     // properties), and class extensions (via direct declaration, or synthesized
@@ -2120,28 +2113,23 @@ void ObjCProtocolDecl::setHasODRHash(bool HasHash) {
 
 void ObjCCategoryDecl::anchor() {}
 
-ObjCCategoryDecl::ObjCCategoryDecl(DeclContext *DC, SourceLocation AtLoc,
-                                   SourceLocation ClassNameLoc,
-                                   SourceLocation CategoryNameLoc,
-                                   IdentifierInfo *Id, ObjCInterfaceDecl *IDecl,
-                                   ObjCTypeParamList *typeParamList,
-                                   SourceLocation IvarLBraceLoc,
-                                   SourceLocation IvarRBraceLoc)
+ObjCCategoryDecl::ObjCCategoryDecl(
+    DeclContext *DC, SourceLocation AtLoc, SourceLocation ClassNameLoc,
+    SourceLocation CategoryNameLoc, const IdentifierInfo *Id,
+    ObjCInterfaceDecl *IDecl, ObjCTypeParamList *typeParamList,
+    SourceLocation IvarLBraceLoc, SourceLocation IvarRBraceLoc)
     : ObjCContainerDecl(ObjCCategory, DC, Id, ClassNameLoc, AtLoc),
       ClassInterface(IDecl), CategoryNameLoc(CategoryNameLoc),
       IvarLBraceLoc(IvarLBraceLoc), IvarRBraceLoc(IvarRBraceLoc) {
   setTypeParamList(typeParamList);
 }
 
-ObjCCategoryDecl *ObjCCategoryDecl::Create(ASTContext &C, DeclContext *DC,
-                                           SourceLocation AtLoc,
-                                           SourceLocation ClassNameLoc,
-                                           SourceLocation CategoryNameLoc,
-                                           IdentifierInfo *Id,
-                                           ObjCInterfaceDecl *IDecl,
-                                           ObjCTypeParamList *typeParamList,
-                                           SourceLocation IvarLBraceLoc,
-                                           SourceLocation IvarRBraceLoc) {
+ObjCCategoryDecl *ObjCCategoryDecl::Create(
+    ASTContext &C, DeclContext *DC, SourceLocation AtLoc,
+    SourceLocation ClassNameLoc, SourceLocation CategoryNameLoc,
+    const IdentifierInfo *Id, ObjCInterfaceDecl *IDecl,
+    ObjCTypeParamList *typeParamList, SourceLocation IvarLBraceLoc,
+    SourceLocation IvarRBraceLoc) {
   auto *CatDecl =
       new (C, DC) ObjCCategoryDecl(DC, AtLoc, ClassNameLoc, CategoryNameLoc, Id,
                                    IDecl, typeParamList, IvarLBraceLoc,
@@ -2190,13 +2178,10 @@ void ObjCCategoryDecl::setTypeParamList(ObjCTypeParamList *TPL) {
 
 void ObjCCategoryImplDecl::anchor() {}
 
-ObjCCategoryImplDecl *
-ObjCCategoryImplDecl::Create(ASTContext &C, DeclContext *DC,
-                             IdentifierInfo *Id,
-                             ObjCInterfaceDecl *ClassInterface,
-                             SourceLocation nameLoc,
-                             SourceLocation atStartLoc,
-                             SourceLocation CategoryNameLoc) {
+ObjCCategoryImplDecl *ObjCCategoryImplDecl::Create(
+    ASTContext &C, DeclContext *DC, const IdentifierInfo *Id,
+    ObjCInterfaceDecl *ClassInterface, SourceLocation nameLoc,
+    SourceLocation atStartLoc, SourceLocation CategoryNameLoc) {
   if (ClassInterface && ClassInterface->hasDefinition())
     ClassInterface = ClassInterface->getDefinition();
   return new (C, DC) ObjCCategoryImplDecl(DC, Id, ClassInterface, nameLoc,
@@ -2365,14 +2350,11 @@ ObjCCompatibleAliasDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
 
 void ObjCPropertyDecl::anchor() {}
 
-ObjCPropertyDecl *ObjCPropertyDecl::Create(ASTContext &C, DeclContext *DC,
-                                           SourceLocation L,
-                                           IdentifierInfo *Id,
-                                           SourceLocation AtLoc,
-                                           SourceLocation LParenLoc,
-                                           QualType T,
-                                           TypeSourceInfo *TSI,
-                                           PropertyControl propControl) {
+ObjCPropertyDecl *
+ObjCPropertyDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
+                         const IdentifierInfo *Id, SourceLocation AtLoc,
+                         SourceLocation LParenLoc, QualType T,
+                         TypeSourceInfo *TSI, PropertyControl propControl) {
   return new (C, DC) ObjCPropertyDecl(DC, L, Id, AtLoc, LParenLoc, T, TSI,
                                       propControl);
 }

diff  --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 3c217d6a6a5ae3..571ed81a42e405 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -715,7 +715,7 @@ void TemplateTypeParmDecl::setTypeConstraint(
 
 NonTypeTemplateParmDecl::NonTypeTemplateParmDecl(
     DeclContext *DC, SourceLocation StartLoc, SourceLocation IdLoc, unsigned D,
-    unsigned P, IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
+    unsigned P, const IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
     ArrayRef<QualType> ExpandedTypes, ArrayRef<TypeSourceInfo *> ExpandedTInfos)
     : DeclaratorDecl(NonTypeTemplateParm, DC, IdLoc, Id, T, TInfo, StartLoc),
       TemplateParmPosition(D, P), ParameterPack(true),
@@ -730,12 +730,10 @@ NonTypeTemplateParmDecl::NonTypeTemplateParmDecl(
   }
 }
 
-NonTypeTemplateParmDecl *
-NonTypeTemplateParmDecl::Create(const ASTContext &C, DeclContext *DC,
-                                SourceLocation StartLoc, SourceLocation IdLoc,
-                                unsigned D, unsigned P, IdentifierInfo *Id,
-                                QualType T, bool ParameterPack,
-                                TypeSourceInfo *TInfo) {
+NonTypeTemplateParmDecl *NonTypeTemplateParmDecl::Create(
+    const ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
+    SourceLocation IdLoc, unsigned D, unsigned P, const IdentifierInfo *Id,
+    QualType T, bool ParameterPack, TypeSourceInfo *TInfo) {
   AutoType *AT =
       C.getLangOpts().CPlusPlus20 ? T->getContainedAutoType() : nullptr;
   return new (C, DC,
@@ -748,7 +746,7 @@ NonTypeTemplateParmDecl::Create(const ASTContext &C, DeclContext *DC,
 
 NonTypeTemplateParmDecl *NonTypeTemplateParmDecl::Create(
     const ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
-    SourceLocation IdLoc, unsigned D, unsigned P, IdentifierInfo *Id,
+    SourceLocation IdLoc, unsigned D, unsigned P, const IdentifierInfo *Id,
     QualType T, TypeSourceInfo *TInfo, ArrayRef<QualType> ExpandedTypes,
     ArrayRef<TypeSourceInfo *> ExpandedTInfos) {
   AutoType *AT = TInfo->getType()->getContainedAutoType();

diff  --git a/clang/lib/AST/NSAPI.cpp b/clang/lib/AST/NSAPI.cpp
index 86dee540e9e299..ecc56c13fb7573 100644
--- a/clang/lib/AST/NSAPI.cpp
+++ b/clang/lib/AST/NSAPI.cpp
@@ -56,10 +56,8 @@ Selector NSAPI::getNSStringSelector(NSStringMethodKind MK) const {
                                        &Ctx.Idents.get("initWithUTF8String"));
       break;
     case NSStr_stringWithCStringEncoding: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("stringWithCString"),
-        &Ctx.Idents.get("encoding")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("stringWithCString"),
+                                           &Ctx.Idents.get("encoding")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -93,10 +91,8 @@ Selector NSAPI::getNSArraySelector(NSArrayMethodKind MK) const {
       Sel = Ctx.Selectors.getUnarySelector(&Ctx.Idents.get("arrayWithObjects"));
       break;
     case NSArr_arrayWithObjectsCount: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("arrayWithObjects"),
-        &Ctx.Idents.get("count")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("arrayWithObjects"),
+                                           &Ctx.Idents.get("count")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -110,10 +106,9 @@ Selector NSAPI::getNSArraySelector(NSArrayMethodKind MK) const {
       Sel = Ctx.Selectors.getUnarySelector(&Ctx.Idents.get("objectAtIndex"));
       break;
     case NSMutableArr_replaceObjectAtIndex: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("replaceObjectAtIndex"),
-        &Ctx.Idents.get("withObject")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("replaceObjectAtIndex"),
+          &Ctx.Idents.get("withObject")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -121,18 +116,14 @@ Selector NSAPI::getNSArraySelector(NSArrayMethodKind MK) const {
       Sel = Ctx.Selectors.getUnarySelector(&Ctx.Idents.get("addObject"));
       break;
     case NSMutableArr_insertObjectAtIndex: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("insertObject"),
-        &Ctx.Idents.get("atIndex")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("insertObject"),
+                                           &Ctx.Idents.get("atIndex")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSMutableArr_setObjectAtIndexedSubscript: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("setObject"),
-        &Ctx.Idents.get("atIndexedSubscript")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("setObject"), &Ctx.Idents.get("atIndexedSubscript")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -167,27 +158,21 @@ Selector NSAPI::getNSDictionarySelector(
                                    &Ctx.Idents.get("dictionaryWithDictionary"));
       break;
     case NSDict_dictionaryWithObjectForKey: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("dictionaryWithObject"),
-        &Ctx.Idents.get("forKey")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("dictionaryWithObject"), &Ctx.Idents.get("forKey")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSDict_dictionaryWithObjectsForKeys: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("dictionaryWithObjects"),
-        &Ctx.Idents.get("forKeys")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("dictionaryWithObjects"), &Ctx.Idents.get("forKeys")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSDict_dictionaryWithObjectsForKeysCount: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("dictionaryWithObjects"),
-        &Ctx.Idents.get("forKeys"),
-        &Ctx.Idents.get("count")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("dictionaryWithObjects"), &Ctx.Idents.get("forKeys"),
+          &Ctx.Idents.get("count")};
       Sel = Ctx.Selectors.getSelector(3, KeyIdents);
       break;
     }
@@ -204,10 +189,8 @@ Selector NSAPI::getNSDictionarySelector(
                                      &Ctx.Idents.get("initWithObjectsAndKeys"));
       break;
     case NSDict_initWithObjectsForKeys: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("initWithObjects"),
-        &Ctx.Idents.get("forKeys")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("initWithObjects"),
+                                           &Ctx.Idents.get("forKeys")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -215,26 +198,20 @@ Selector NSAPI::getNSDictionarySelector(
       Sel = Ctx.Selectors.getUnarySelector(&Ctx.Idents.get("objectForKey"));
       break;
     case NSMutableDict_setObjectForKey: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("setObject"),
-        &Ctx.Idents.get("forKey")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("setObject"),
+                                           &Ctx.Idents.get("forKey")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSMutableDict_setObjectForKeyedSubscript: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("setObject"),
-        &Ctx.Idents.get("forKeyedSubscript")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("setObject"), &Ctx.Idents.get("forKeyedSubscript")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSMutableDict_setValueForKey: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("setValue"),
-        &Ctx.Idents.get("forKey")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("setValue"),
+                                           &Ctx.Idents.get("forKey")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -264,34 +241,27 @@ Selector NSAPI::getNSSetSelector(NSSetMethodKind MK) const {
       Sel = Ctx.Selectors.getUnarySelector(&Ctx.Idents.get("addObject"));
       break;
     case NSOrderedSet_insertObjectAtIndex: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("insertObject"),
-        &Ctx.Idents.get("atIndex")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("insertObject"),
+                                           &Ctx.Idents.get("atIndex")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSOrderedSet_setObjectAtIndex: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("setObject"),
-        &Ctx.Idents.get("atIndex")
-      };
+      const IdentifierInfo *KeyIdents[] = {&Ctx.Idents.get("setObject"),
+                                           &Ctx.Idents.get("atIndex")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSOrderedSet_setObjectAtIndexedSubscript: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("setObject"),
-        &Ctx.Idents.get("atIndexedSubscript")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("setObject"), &Ctx.Idents.get("atIndexedSubscript")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
     case NSOrderedSet_replaceObjectAtIndexWithObject: {
-      IdentifierInfo *KeyIdents[] = {
-        &Ctx.Idents.get("replaceObjectAtIndex"),
-        &Ctx.Idents.get("withObject")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &Ctx.Idents.get("replaceObjectAtIndex"),
+          &Ctx.Idents.get("withObject")};
       Sel = Ctx.Selectors.getSelector(2, KeyIdents);
       break;
     }
@@ -606,7 +576,7 @@ bool NSAPI::isObjCEnumerator(const Expr *E,
 Selector NSAPI::getOrInitSelector(ArrayRef<StringRef> Ids,
                                   Selector &Sel) const {
   if (Sel.isNull()) {
-    SmallVector<IdentifierInfo *, 4> Idents;
+    SmallVector<const IdentifierInfo *, 4> Idents;
     for (ArrayRef<StringRef>::const_iterator
            I = Ids.begin(), E = Ids.end(); I != E; ++I)
       Idents.push_back(&Ctx.Idents.get(*I));
@@ -617,7 +587,7 @@ Selector NSAPI::getOrInitSelector(ArrayRef<StringRef> Ids,
 
 Selector NSAPI::getOrInitNullarySelector(StringRef Id, Selector &Sel) const {
   if (Sel.isNull()) {
-    IdentifierInfo *Ident = &Ctx.Idents.get(Id);
+    const IdentifierInfo *Ident = &Ctx.Idents.get(Id);
     Sel = Ctx.Selectors.getSelector(0, &Ident);
   }
   return Sel;

diff  --git a/clang/lib/AST/NestedNameSpecifier.cpp b/clang/lib/AST/NestedNameSpecifier.cpp
index 36f2c47b30005d..785c46e86a77c5 100644
--- a/clang/lib/AST/NestedNameSpecifier.cpp
+++ b/clang/lib/AST/NestedNameSpecifier.cpp
@@ -55,16 +55,16 @@ NestedNameSpecifier::FindOrInsert(const ASTContext &Context,
   return NNS;
 }
 
-NestedNameSpecifier *
-NestedNameSpecifier::Create(const ASTContext &Context,
-                            NestedNameSpecifier *Prefix, IdentifierInfo *II) {
+NestedNameSpecifier *NestedNameSpecifier::Create(const ASTContext &Context,
+                                                 NestedNameSpecifier *Prefix,
+                                                 const IdentifierInfo *II) {
   assert(II && "Identifier cannot be NULL");
   assert((!Prefix || Prefix->isDependent()) && "Prefix must be dependent");
 
   NestedNameSpecifier Mockup;
   Mockup.Prefix.setPointer(Prefix);
   Mockup.Prefix.setInt(StoredIdentifier);
-  Mockup.Specifier = II;
+  Mockup.Specifier = const_cast<IdentifierInfo *>(II);
   return FindOrInsert(Context, Mockup);
 }
 
@@ -87,7 +87,7 @@ NestedNameSpecifier::Create(const ASTContext &Context,
 NestedNameSpecifier *
 NestedNameSpecifier::Create(const ASTContext &Context,
                             NestedNameSpecifier *Prefix,
-                            NamespaceAliasDecl *Alias) {
+                            const NamespaceAliasDecl *Alias) {
   assert(Alias && "Namespace alias cannot be NULL");
   assert((!Prefix ||
           (Prefix->getAsType() == nullptr &&
@@ -96,7 +96,7 @@ NestedNameSpecifier::Create(const ASTContext &Context,
   NestedNameSpecifier Mockup;
   Mockup.Prefix.setPointer(Prefix);
   Mockup.Prefix.setInt(StoredDecl);
-  Mockup.Specifier = Alias;
+  Mockup.Specifier = const_cast<NamespaceAliasDecl *>(Alias);
   return FindOrInsert(Context, Mockup);
 }
 
@@ -112,13 +112,13 @@ NestedNameSpecifier::Create(const ASTContext &Context,
   return FindOrInsert(Context, Mockup);
 }
 
-NestedNameSpecifier *
-NestedNameSpecifier::Create(const ASTContext &Context, IdentifierInfo *II) {
+NestedNameSpecifier *NestedNameSpecifier::Create(const ASTContext &Context,
+                                                 const IdentifierInfo *II) {
   assert(II && "Identifier cannot be NULL");
   NestedNameSpecifier Mockup;
   Mockup.Prefix.setPointer(nullptr);
   Mockup.Prefix.setInt(StoredIdentifier);
-  Mockup.Specifier = II;
+  Mockup.Specifier = const_cast<IdentifierInfo *>(II);
   return FindOrInsert(Context, Mockup);
 }
 

diff  --git a/clang/lib/AST/SelectorLocationsKind.cpp b/clang/lib/AST/SelectorLocationsKind.cpp
index 2c34c9c60c2b20..ebe6324f904c78 100644
--- a/clang/lib/AST/SelectorLocationsKind.cpp
+++ b/clang/lib/AST/SelectorLocationsKind.cpp
@@ -26,7 +26,7 @@ static SourceLocation getStandardSelLoc(unsigned Index,
     assert(Index == 0);
     if (EndLoc.isInvalid())
       return SourceLocation();
-    IdentifierInfo *II = Sel.getIdentifierInfoForSlot(0);
+    const IdentifierInfo *II = Sel.getIdentifierInfoForSlot(0);
     unsigned Len = II ? II->getLength() : 0;
     return EndLoc.getLocWithOffset(-Len);
   }
@@ -34,7 +34,7 @@ static SourceLocation getStandardSelLoc(unsigned Index,
   assert(Index < NumSelArgs);
   if (ArgLoc.isInvalid())
     return SourceLocation();
-  IdentifierInfo *II = Sel.getIdentifierInfoForSlot(Index);
+  const IdentifierInfo *II = Sel.getIdentifierInfoForSlot(Index);
   unsigned Len = /* selector id */ (II ? II->getLength() : 0) + /* ':' */ 1;
   if (WithArgSpace)
     ++Len;

diff  --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index 2ba93d17f2675d..5855ab3141edcc 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -1447,7 +1447,7 @@ void StmtPrinter::VisitOffsetOfExpr(OffsetOfExpr *Node) {
       continue;
 
     // Field or identifier node.
-    IdentifierInfo *Id = ON.getFieldName();
+    const IdentifierInfo *Id = ON.getFieldName();
     if (!Id)
       continue;
 
@@ -2348,7 +2348,7 @@ void StmtPrinter::VisitCXXPseudoDestructorExpr(CXXPseudoDestructorExpr *E) {
     E->getQualifier()->print(OS, Policy);
   OS << "~";
 
-  if (IdentifierInfo *II = E->getDestroyedTypeIdentifier())
+  if (const IdentifierInfo *II = E->getDestroyedTypeIdentifier())
     OS << II->getName();
   else
     E->getDestroyedType().print(OS, Policy);

diff  --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
index be3dd4b673cf98..01e1d1cc8289bf 100644
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -61,7 +61,7 @@ namespace {
     virtual void VisitName(DeclarationName Name, bool TreatAsDecl = false) = 0;
 
     /// Visit identifiers that are not in Decl's or Type's.
-    virtual void VisitIdentifierInfo(IdentifierInfo *II) = 0;
+    virtual void VisitIdentifierInfo(const IdentifierInfo *II) = 0;
 
     /// Visit a nested-name-specifier that occurs within an expression
     /// or statement.
@@ -163,7 +163,7 @@ namespace {
       ID.AddPointer(Name.getAsOpaquePtr());
     }
 
-    void VisitIdentifierInfo(IdentifierInfo *II) override {
+    void VisitIdentifierInfo(const IdentifierInfo *II) override {
       ID.AddPointer(II);
     }
 
@@ -211,7 +211,7 @@ namespace {
       }
       Hash.AddDeclarationName(Name, TreatAsDecl);
     }
-    void VisitIdentifierInfo(IdentifierInfo *II) override {
+    void VisitIdentifierInfo(const IdentifierInfo *II) override {
       ID.AddBoolean(II);
       if (II) {
         Hash.AddIdentifierInfo(II);

diff  --git a/clang/lib/Analysis/ObjCNoReturn.cpp b/clang/lib/Analysis/ObjCNoReturn.cpp
index 9d7c365c3b9924..9e651c29e085da 100644
--- a/clang/lib/Analysis/ObjCNoReturn.cpp
+++ b/clang/lib/Analysis/ObjCNoReturn.cpp
@@ -17,7 +17,8 @@
 
 using namespace clang;
 
-static bool isSubclass(const ObjCInterfaceDecl *Class, IdentifierInfo *II) {
+static bool isSubclass(const ObjCInterfaceDecl *Class,
+                       const IdentifierInfo *II) {
   if (!Class)
     return false;
   if (Class->getIdentifier() == II)
@@ -30,7 +31,7 @@ ObjCNoReturn::ObjCNoReturn(ASTContext &C)
     NSExceptionII(&C.Idents.get("NSException"))
 {
   // Generate selectors.
-  SmallVector<IdentifierInfo*, 3> II;
+  SmallVector<const IdentifierInfo *, 3> II;
 
   // raise:format:
   II.push_back(&C.Idents.get("raise"));

diff  --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp
index a9b07aca65c052..feea84544d62fb 100644
--- a/clang/lib/Basic/IdentifierTable.cpp
+++ b/clang/lib/Basic/IdentifierTable.cpp
@@ -541,7 +541,8 @@ unsigned Selector::getNumArgs() const {
   return SI->getNumArgs();
 }
 
-IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
+const IdentifierInfo *
+Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
   if (getIdentifierInfoFlag() < MultiArg) {
     assert(argIndex == 0 && "illegal keyword index");
     return getAsIdentifierInfo();
@@ -553,7 +554,7 @@ IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
 }
 
 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
-  IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
+  const IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
   return II ? II->getName() : StringRef();
 }
 
@@ -574,7 +575,7 @@ std::string Selector::getAsString() const {
     return "<null selector>";
 
   if (getIdentifierInfoFlag() < MultiArg) {
-    IdentifierInfo *II = getAsIdentifierInfo();
+    const IdentifierInfo *II = getAsIdentifierInfo();
 
     if (getNumArgs() == 0) {
       assert(II && "If the number of arguments is 0 then II is guaranteed to "
@@ -608,7 +609,7 @@ static bool startsWithWord(StringRef name, StringRef word) {
 }
 
 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
-  IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
+  const IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
   if (!first) return OMF_None;
 
   StringRef name = first->getName();
@@ -655,7 +656,7 @@ ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
 }
 
 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
-  IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
+  const IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
   if (!first) return OIT_None;
 
   StringRef name = first->getName();
@@ -683,7 +684,7 @@ ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
 }
 
 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
-  IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
+  const IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
   if (!first) return SFF_None;
 
   StringRef name = first->getName();
@@ -750,7 +751,8 @@ size_t SelectorTable::getTotalMemory() const {
   return SelTabImpl.Allocator.getTotalMemory();
 }
 
-Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
+Selector SelectorTable::getSelector(unsigned nKeys,
+                                    const IdentifierInfo **IIV) {
   if (nKeys < 2)
     return Selector(IIV[0], nKeys);
 

diff  --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 47f063b5501cc6..2742c39965b2c8 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1447,7 +1447,7 @@ llvm::Function *CodeGenFunction::GenerateBlockFunction(
     selfTy = getContext().getPointerType(getContext().getAddrSpaceQualType(
         getContext().VoidTy, LangAS::opencl_generic));
 
-  IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
+  const IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
 
   ImplicitParamDecl SelfDecl(getContext(), const_cast<BlockDecl *>(blockDecl),
                              SourceLocation(), II, selfTy,
@@ -2791,7 +2791,7 @@ static void configureBlocksRuntimeObject(CodeGenModule &CGM,
   auto *GV = cast<llvm::GlobalValue>(C->stripPointerCasts());
 
   if (CGM.getTarget().getTriple().isOSBinFormatCOFF()) {
-    IdentifierInfo &II = CGM.getContext().Idents.get(C->getName());
+    const IdentifierInfo &II = CGM.getContext().Idents.get(C->getName());
     TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
     DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
 

diff  --git a/clang/lib/CodeGen/CGCUDANV.cpp b/clang/lib/CodeGen/CGCUDANV.cpp
index 0cb5b06a519c00..370642cb3d5364 100644
--- a/clang/lib/CodeGen/CGCUDANV.cpp
+++ b/clang/lib/CodeGen/CGCUDANV.cpp
@@ -361,7 +361,7 @@ void CGNVCUDARuntime::emitDeviceStubBodyNew(CodeGenFunction &CGF,
       KernelLaunchAPI = KernelLaunchAPI + "_ptsz";
   }
   auto LaunchKernelName = addPrefixToName(KernelLaunchAPI);
-  IdentifierInfo &cudaLaunchKernelII =
+  const IdentifierInfo &cudaLaunchKernelII =
       CGM.getContext().Idents.get(LaunchKernelName);
   FunctionDecl *cudaLaunchKernelFD = nullptr;
   for (auto *Result : DC->lookup(&cudaLaunchKernelII)) {

diff  --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 4f4013292b1fc0..8bdafa7c569b08 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1384,7 +1384,7 @@ void CodeGenFunction::EmitAndRegisterVariableArrayDimensions(
   // For each dimension stores its QualType and corresponding
   // size-expression Value.
   SmallVector<CodeGenFunction::VlaSizePair, 4> Dimensions;
-  SmallVector<IdentifierInfo *, 4> VLAExprNames;
+  SmallVector<const IdentifierInfo *, 4> VLAExprNames;
 
   // Break down the array into individual dimensions.
   QualType Type1D = D.getType();
@@ -1421,7 +1421,7 @@ void CodeGenFunction::EmitAndRegisterVariableArrayDimensions(
       MD = llvm::ConstantAsMetadata::get(C);
     else {
       // Create an artificial VarDecl to generate debug info for.
-      IdentifierInfo *NameIdent = VLAExprNames[NameIdx++];
+      const IdentifierInfo *NameIdent = VLAExprNames[NameIdx++];
       auto QT = getContext().getIntTypeForBitwidth(
           SizeTy->getScalarSizeInBits(), false);
       auto *ArtificialDecl = VarDecl::Create(

diff  --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index c7f497a7c8451b..ee571995ce4c3f 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -1789,11 +1789,10 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
   static const unsigned NumItems = 16;
 
   // Fetch the countByEnumeratingWithState:objects:count: selector.
-  IdentifierInfo *II[] = {
-    &CGM.getContext().Idents.get("countByEnumeratingWithState"),
-    &CGM.getContext().Idents.get("objects"),
-    &CGM.getContext().Idents.get("count")
-  };
+  const IdentifierInfo *II[] = {
+      &CGM.getContext().Idents.get("countByEnumeratingWithState"),
+      &CGM.getContext().Idents.get("objects"),
+      &CGM.getContext().Idents.get("count")};
   Selector FastEnumSel =
       CGM.getContext().Selectors.getSelector(std::size(II), &II[0]);
 
@@ -2720,7 +2719,7 @@ llvm::Value *CodeGenFunction::EmitObjCMRRAutoreleasePoolPush() {
   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
   llvm::Value *Receiver = Runtime.EmitNSAutoreleasePoolClassRef(*this);
   // [NSAutoreleasePool alloc]
-  IdentifierInfo *II = &CGM.getContext().Idents.get("alloc");
+  const IdentifierInfo *II = &CGM.getContext().Idents.get("alloc");
   Selector AllocSel = getContext().Selectors.getSelector(0, &II);
   CallArgList Args;
   RValue AllocRV =
@@ -2767,7 +2766,7 @@ llvm::Value *CodeGenFunction::EmitObjCAllocInit(llvm::Value *value,
 /// Produce the code to do a primitive release.
 /// [tmp drain];
 void CodeGenFunction::EmitObjCMRRAutoreleasePoolPop(llvm::Value *Arg) {
-  IdentifierInfo *II = &CGM.getContext().Idents.get("drain");
+  const IdentifierInfo *II = &CGM.getContext().Idents.get("drain");
   Selector DrainSel = getContext().Selectors.getSelector(0, &II);
   CallArgList Args;
   CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
@@ -3715,8 +3714,8 @@ CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
   if ((HelperFn = CGM.getAtomicSetterHelperFnMap(Ty)))
     return HelperFn;
 
-  IdentifierInfo *II
-    = &CGM.getContext().Idents.get("__assign_helper_atomic_property_");
+  const IdentifierInfo *II =
+      &CGM.getContext().Idents.get("__assign_helper_atomic_property_");
 
   QualType ReturnTy = C.VoidTy;
   QualType DestTy = C.getPointerType(Ty);
@@ -3813,7 +3812,7 @@ llvm::Constant *CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
   if ((HelperFn = CGM.getAtomicGetterHelperFnMap(Ty)))
     return HelperFn;
 
-  IdentifierInfo *II =
+  const IdentifierInfo *II =
       &CGM.getContext().Idents.get("__copy_helper_atomic_property_");
 
   QualType ReturnTy = C.VoidTy;
@@ -3907,10 +3906,10 @@ llvm::Constant *CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
 llvm::Value *
 CodeGenFunction::EmitBlockCopyAndAutorelease(llvm::Value *Block, QualType Ty) {
   // Get selectors for retain/autorelease.
-  IdentifierInfo *CopyID = &getContext().Idents.get("copy");
+  const IdentifierInfo *CopyID = &getContext().Idents.get("copy");
   Selector CopySelector =
       getContext().Selectors.getNullarySelector(CopyID);
-  IdentifierInfo *AutoreleaseID = &getContext().Idents.get("autorelease");
+  const IdentifierInfo *AutoreleaseID = &getContext().Idents.get("autorelease");
   Selector AutoreleaseSelector =
       getContext().Selectors.getNullarySelector(AutoreleaseID);
 

diff  --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 8a599c10e1caf1..042cd5d46da4b2 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -1555,12 +1555,12 @@ class CGObjCNonFragileABIMac : public CGObjCCommonMac {
 
   // Shamelessly stolen from Analysis/CFRefCount.cpp
   Selector GetNullarySelector(const char* name) const {
-    IdentifierInfo* II = &CGM.getContext().Idents.get(name);
+    const IdentifierInfo *II = &CGM.getContext().Idents.get(name);
     return CGM.getContext().Selectors.getSelector(0, &II);
   }
 
   Selector GetUnarySelector(const char* name) const {
-    IdentifierInfo* II = &CGM.getContext().Idents.get(name);
+    const IdentifierInfo *II = &CGM.getContext().Idents.get(name);
     return CGM.getContext().Selectors.getSelector(1, &II);
   }
 
@@ -6268,11 +6268,10 @@ bool CGObjCNonFragileABIMac::isVTableDispatchedSelector(Selector Sel) {
       VTableDispatchMethods.insert(GetUnarySelector("addObject"));
 
       // "countByEnumeratingWithState:objects:count"
-      IdentifierInfo *KeyIdents[] = {
-        &CGM.getContext().Idents.get("countByEnumeratingWithState"),
-        &CGM.getContext().Idents.get("objects"),
-        &CGM.getContext().Idents.get("count")
-      };
+      const IdentifierInfo *KeyIdents[] = {
+          &CGM.getContext().Idents.get("countByEnumeratingWithState"),
+          &CGM.getContext().Idents.get("objects"),
+          &CGM.getContext().Idents.get("count")};
       VTableDispatchMethods.insert(
         CGM.getContext().Selectors.getSelector(3, KeyIdents));
     }

diff  --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index a2d746bb8f4f9d..87766a758311d5 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -828,7 +828,7 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
   // .cxx_destruct, __destroy_helper_block_ and all of their calees at run time.
   if (SanOpts.has(SanitizerKind::Thread)) {
     if (const auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(D)) {
-      IdentifierInfo *II = OMD->getSelector().getIdentifierInfoForSlot(0);
+      const IdentifierInfo *II = OMD->getSelector().getIdentifierInfoForSlot(0);
       if (OMD->getMethodFamily() == OMF_dealloc ||
           OMD->getMethodFamily() == OMF_initialize ||
           (OMD->getSelector().isUnarySelector() && II->isStr(".cxx_destruct"))) {

diff  --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 75519be8bba052..b15031dca46862 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -6626,7 +6626,7 @@ static bool AllTrivialInitializers(CodeGenModule &CGM,
 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
   // We might need a .cxx_destruct even if we don't have any ivar initializers.
   if (needsDestructMethod(D)) {
-    IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct");
+    const IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct");
     Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
     ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(
         getContext(), D->getLocation(), D->getLocation(), cxxSelector,
@@ -6646,7 +6646,7 @@ void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
       AllTrivialInitializers(*this, D))
     return;
 
-  IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");
+  const IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");
   Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
   // The constructor returns 'self'.
   ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(
@@ -7214,7 +7214,7 @@ void CodeGenModule::EmitStaticExternCAliases() {
   if (!getTargetCodeGenInfo().shouldEmitStaticExternCAliases())
     return;
   for (auto &I : StaticExternCValues) {
-    IdentifierInfo *Name = I.first;
+    const IdentifierInfo *Name = I.first;
     llvm::GlobalValue *Val = I.second;
 
     // If Val is null, that implies there were multiple declarations that each

diff  --git a/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp b/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
index 1f40db785981d6..6ae955a2380b74 100644
--- a/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
+++ b/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
@@ -592,7 +592,7 @@ namespace {
     }
 
     bool ImplementationIsNonLazy(const ObjCImplDecl *OD) const {
-      IdentifierInfo* II = &Context->Idents.get("load");
+      const IdentifierInfo *II = &Context->Idents.get("load");
       Selector LoadSel = Context->Selectors.getSelector(0, &II);
       return OD->getClassMethod(LoadSel) != nullptr;
     }

diff  --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 7dffcf0e941e09..f0750e5336b6a5 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -64,8 +64,7 @@ HeaderFileInfo::getControllingMacro(ExternalPreprocessorSource *External) {
     if (ControllingMacro->isOutOfDate()) {
       assert(External && "We must have an external source if we have a "
                          "controlling macro that is out of date.");
-      External->updateOutOfDateIdentifier(
-          *const_cast<IdentifierInfo *>(ControllingMacro));
+      External->updateOutOfDateIdentifier(*ControllingMacro);
     }
     return ControllingMacro;
   }

diff  --git a/clang/lib/Lex/MacroInfo.cpp b/clang/lib/Lex/MacroInfo.cpp
index 39bb0f44eff25b..dfdf463665f3c1 100644
--- a/clang/lib/Lex/MacroInfo.cpp
+++ b/clang/lib/Lex/MacroInfo.cpp
@@ -257,7 +257,7 @@ LLVM_DUMP_METHOD void MacroDirective::dump() const {
 }
 
 ModuleMacro *ModuleMacro::create(Preprocessor &PP, Module *OwningModule,
-                                 IdentifierInfo *II, MacroInfo *Macro,
+                                 const IdentifierInfo *II, MacroInfo *Macro,
                                  ArrayRef<ModuleMacro *> Overrides) {
   void *Mem = PP.getPreprocessorAllocator().Allocate(
       sizeof(ModuleMacro) + sizeof(ModuleMacro *) * Overrides.size(),

diff  --git a/clang/lib/Lex/PPLexerChange.cpp b/clang/lib/Lex/PPLexerChange.cpp
index 3b1b6df1dbae4e..2ca2122ac71099 100644
--- a/clang/lib/Lex/PPLexerChange.cpp
+++ b/clang/lib/Lex/PPLexerChange.cpp
@@ -368,8 +368,7 @@ bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
       // Okay, this has a controlling macro, remember in HeaderFileInfo.
       if (OptionalFileEntryRef FE = CurPPLexer->getFileEntry()) {
         HeaderInfo.SetFileControllingMacro(*FE, ControllingMacro);
-        if (MacroInfo *MI =
-              getMacroInfo(const_cast<IdentifierInfo*>(ControllingMacro)))
+        if (MacroInfo *MI = getMacroInfo(ControllingMacro))
           MI->setUsedForHeaderGuard(true);
         if (const IdentifierInfo *DefinedMacro =
               CurPPLexer->MIOpt.GetDefinedMacro()) {
@@ -805,7 +804,7 @@ Module *Preprocessor::LeaveSubmodule(bool ForPragma) {
   llvm::SmallPtrSet<const IdentifierInfo*, 8> VisitedMacros;
   for (unsigned I = Info.OuterPendingModuleMacroNames;
        I != PendingModuleMacroNames.size(); ++I) {
-    auto *II = const_cast<IdentifierInfo*>(PendingModuleMacroNames[I]);
+    const auto *II = PendingModuleMacroNames[I];
     if (!VisitedMacros.insert(II).second)
       continue;
 
@@ -855,8 +854,8 @@ Module *Preprocessor::LeaveSubmodule(bool ForPragma) {
         // Don't bother creating a module macro if it would represent a #undef
         // that doesn't override anything.
         if (Def || !Macro.getOverriddenMacros().empty())
-          addModuleMacro(LeavingMod, II, Def,
-                         Macro.getOverriddenMacros(), IsNew);
+          addModuleMacro(LeavingMod, II, Def, Macro.getOverriddenMacros(),
+                         IsNew);
 
         if (!getLangOpts().ModulesLocalVisibility) {
           // This macro is exposed to the rest of this compilation as a

diff  --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 516269c0c6013e..a5f22f01682d25 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -129,7 +129,7 @@ void Preprocessor::setLoadedMacroDirective(IdentifierInfo *II,
     II->setHasMacroDefinition(false);
 }
 
-ModuleMacro *Preprocessor::addModuleMacro(Module *Mod, IdentifierInfo *II,
+ModuleMacro *Preprocessor::addModuleMacro(Module *Mod, const IdentifierInfo *II,
                                           MacroInfo *Macro,
                                           ArrayRef<ModuleMacro *> Overrides,
                                           bool &New) {
@@ -162,7 +162,7 @@ ModuleMacro *Preprocessor::addModuleMacro(Module *Mod, IdentifierInfo *II,
   // The new macro is always a leaf macro.
   LeafMacros.push_back(MM);
   // The identifier now has defined macros (that may or may not be visible).
-  II->setHasMacroDefinition(true);
+  const_cast<IdentifierInfo *>(II)->setHasMacroDefinition(true);
 
   New = true;
   return MM;

diff  --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index 031ed1e16bb8fc..0b70192743a399 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -759,7 +759,7 @@ void Preprocessor::HandlePoisonedIdentifier(Token & Identifier) {
     Diag(Identifier,it->second) << Identifier.getIdentifierInfo();
 }
 
-void Preprocessor::updateOutOfDateIdentifier(IdentifierInfo &II) const {
+void Preprocessor::updateOutOfDateIdentifier(const IdentifierInfo &II) const {
   assert(II.isOutOfDate() && "not out of date");
   getExternalSource()->updateOutOfDateIdentifier(II);
 }

diff  --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 0aa14b0510746b..583232f2d610d0 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -7700,7 +7700,7 @@ void Parser::ParseParameterDeclarationClause(
     }
 
     // Remember this parsed parameter in ParamInfo.
-    IdentifierInfo *ParmII = ParmDeclarator.getIdentifier();
+    const IdentifierInfo *ParmII = ParmDeclarator.getIdentifier();
 
     // DefArgToks is used when the parsing of default arguments needs
     // to be delayed.

diff  --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 861a25dc5103c1..477d81cdc2c230 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -616,7 +616,7 @@ bool Parser::ParseUsingDeclarator(DeclaratorContext Context,
   }
 
   // Parse nested-name-specifier.
-  IdentifierInfo *LastII = nullptr;
+  const IdentifierInfo *LastII = nullptr;
   if (ParseOptionalCXXScopeSpecifier(D.SS, /*ObjectType=*/nullptr,
                                      /*ObjectHasErrors=*/false,
                                      /*EnteringContext=*/false,

diff  --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index 73c85c585baae4..43d6105dcf31c4 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -157,7 +157,8 @@ void Parser::CheckForTemplateAndDigraph(Token &Next, ParsedType ObjectType,
 bool Parser::ParseOptionalCXXScopeSpecifier(
     CXXScopeSpec &SS, ParsedType ObjectType, bool ObjectHadErrors,
     bool EnteringContext, bool *MayBePseudoDestructor, bool IsTypename,
-    IdentifierInfo **LastII, bool OnlyNamespace, bool InUsingDeclaration) {
+    const IdentifierInfo **LastII, bool OnlyNamespace,
+    bool InUsingDeclaration) {
   assert(getLangOpts().CPlusPlus &&
          "Call sites of this function should be guarded by checking for C++");
 
@@ -2626,7 +2627,7 @@ bool Parser::ParseUnqualifiedIdTemplateId(
     // UnqualifiedId.
 
     // FIXME: Store name for literal operator too.
-    IdentifierInfo *TemplateII =
+    const IdentifierInfo *TemplateII =
         Id.getKind() == UnqualifiedIdKind::IK_Identifier ? Id.Identifier
                                                          : nullptr;
     OverloadedOperatorKind OpKind =

diff  --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 88bab0eb27a3ed..887d7a36cee7e9 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -799,11 +799,11 @@ void Parser::ParseObjCInterfaceDeclList(tok::ObjCKeywordKind contextKey,
                                              addedToDeclSpec);
 
         // Install the property declarator into interfaceDecl.
-        IdentifierInfo *SelName =
+        const IdentifierInfo *SelName =
             OCDS.getGetterName() ? OCDS.getGetterName() : FD.D.getIdentifier();
 
         Selector GetterSel = PP.getSelectorTable().getNullarySelector(SelName);
-        IdentifierInfo *SetterName = OCDS.getSetterName();
+        const IdentifierInfo *SetterName = OCDS.getSetterName();
         Selector SetterSel;
         if (SetterName)
           SetterSel = PP.getSelectorTable().getSelector(1, &SetterName);
@@ -1445,7 +1445,7 @@ Decl *Parser::ParseObjCMethodDecl(SourceLocation mLoc,
     return Result;
   }
 
-  SmallVector<IdentifierInfo *, 12> KeyIdents;
+  SmallVector<const IdentifierInfo *, 12> KeyIdents;
   SmallVector<SourceLocation, 12> KeyLocs;
   SmallVector<Sema::ObjCArgInfo, 12> ArgInfos;
   ParseScope PrototypeScope(this, Scope::FunctionPrototypeScope |
@@ -1541,7 +1541,7 @@ Decl *Parser::ParseObjCMethodDecl(SourceLocation mLoc,
     Declarator ParmDecl(DS, ParsedAttributesView::none(),
                         DeclaratorContext::Prototype);
     ParseDeclarator(ParmDecl);
-    IdentifierInfo *ParmII = ParmDecl.getIdentifier();
+    const IdentifierInfo *ParmII = ParmDecl.getIdentifier();
     Decl *Param = Actions.ActOnParamDeclarator(getCurScope(), ParmDecl);
     CParamInfo.push_back(DeclaratorChunk::ParamInfo(ParmII,
                                                     ParmDecl.getIdentifierLoc(),
@@ -3242,7 +3242,7 @@ Parser::ParseObjCMessageExpressionBody(SourceLocation LBracLoc,
   SourceLocation Loc;
   IdentifierInfo *selIdent = ParseObjCSelectorPiece(Loc);
 
-  SmallVector<IdentifierInfo *, 12> KeyIdents;
+  SmallVector<const IdentifierInfo *, 12> KeyIdents;
   SmallVector<SourceLocation, 12> KeyLocs;
   ExprVector KeyExprs;
 
@@ -3642,7 +3642,7 @@ ExprResult Parser::ParseObjCSelectorExpression(SourceLocation AtLoc) {
   if (Tok.isNot(tok::l_paren))
     return ExprError(Diag(Tok, diag::err_expected_lparen_after) << "@selector");
 
-  SmallVector<IdentifierInfo *, 12> KeyIdents;
+  SmallVector<const IdentifierInfo *, 12> KeyIdents;
   SourceLocation sLoc;
 
   BalancedDelimiterTracker T(*this, tok::l_paren);

diff  --git a/clang/lib/Parse/ParseTemplate.cpp b/clang/lib/Parse/ParseTemplate.cpp
index d4897f8f66072e..03257500426e52 100644
--- a/clang/lib/Parse/ParseTemplate.cpp
+++ b/clang/lib/Parse/ParseTemplate.cpp
@@ -313,7 +313,7 @@ Parser::ParseConceptDefinition(const ParsedTemplateInfo &TemplateInfo,
     return nullptr;
   }
 
-  IdentifierInfo *Id = Result.Identifier;
+  const IdentifierInfo *Id = Result.Identifier;
   SourceLocation IdLoc = Result.getBeginLoc();
 
   DiagnoseAndSkipCXX11Attributes();
@@ -1289,7 +1289,7 @@ bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
     // later.
     Tok.setKind(tok::annot_template_id);
 
-    IdentifierInfo *TemplateII =
+    const IdentifierInfo *TemplateII =
         TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
             ? TemplateName.Identifier
             : nullptr;

diff  --git a/clang/lib/Sema/CodeCompleteConsumer.cpp b/clang/lib/Sema/CodeCompleteConsumer.cpp
index 350bd78b57107b..91713d71786ee5 100644
--- a/clang/lib/Sema/CodeCompleteConsumer.cpp
+++ b/clang/lib/Sema/CodeCompleteConsumer.cpp
@@ -854,7 +854,8 @@ StringRef CodeCompletionResult::getOrderedName(std::string &Saved) const {
   if (IdentifierInfo *Id = Name.getAsIdentifierInfo())
     return Id->getName();
   if (Name.isObjCZeroArgSelector())
-    if (IdentifierInfo *Id = Name.getObjCSelector().getIdentifierInfoForSlot(0))
+    if (const IdentifierInfo *Id =
+            Name.getObjCSelector().getIdentifierInfoForSlot(0))
       return Id->getName();
 
   Saved = Name.getAsString();

diff  --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 801b03a63dbc81..a2ea66f339c8e3 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -92,9 +92,8 @@ DarwinSDKInfo *Sema::getDarwinSDKInfoForAvailabilityChecking() {
   return nullptr;
 }
 
-IdentifierInfo *
-Sema::InventAbbreviatedTemplateParameterTypeName(IdentifierInfo *ParamName,
-                                                 unsigned int Index) {
+IdentifierInfo *Sema::InventAbbreviatedTemplateParameterTypeName(
+    const IdentifierInfo *ParamName, unsigned int Index) {
   std::string InventedName;
   llvm::raw_string_ostream OS(InventedName);
 

diff  --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index 83ebcaf9e765a7..c335017f243eb2 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -3691,7 +3691,7 @@ CodeCompletionString *CodeCompletionResult::createCodeCompletionStringForDecl(
         std::string Keyword;
         if (Idx > StartParameter)
           Result.AddChunk(CodeCompletionString::CK_HorizontalSpace);
-        if (IdentifierInfo *II = Sel.getIdentifierInfoForSlot(Idx))
+        if (const IdentifierInfo *II = Sel.getIdentifierInfoForSlot(Idx))
           Keyword += II->getName();
         Keyword += ":";
         if (Idx < StartParameter || AllParametersAreInformative)
@@ -3720,7 +3720,7 @@ CodeCompletionString *CodeCompletionResult::createCodeCompletionStringForDecl(
         Arg = "(" + formatObjCParamQualifiers((*P)->getObjCDeclQualifier(),
                                               ParamType);
         Arg += ParamType.getAsString(Policy) + ")";
-        if (IdentifierInfo *II = (*P)->getIdentifier())
+        if (const IdentifierInfo *II = (*P)->getIdentifier())
           if (DeclaringEntity || AllParametersAreInformative)
             Arg += II->getName();
       }
@@ -4500,11 +4500,11 @@ void Sema::CodeCompleteOrdinaryName(Scope *S,
                             Results.data(), Results.size());
 }
 
-static void AddClassMessageCompletions(Sema &SemaRef, Scope *S,
-                                       ParsedType Receiver,
-                                       ArrayRef<IdentifierInfo *> SelIdents,
-                                       bool AtArgumentExpression, bool IsSuper,
-                                       ResultBuilder &Results);
+static void
+AddClassMessageCompletions(Sema &SemaRef, Scope *S, ParsedType Receiver,
+                           ArrayRef<const IdentifierInfo *> SelIdents,
+                           bool AtArgumentExpression, bool IsSuper,
+                           ResultBuilder &Results);
 
 void Sema::CodeCompleteDeclSpec(Scope *S, DeclSpec &DS,
                                 bool AllowNonIdentifiers,
@@ -4928,7 +4928,7 @@ void Sema::CodeCompletePostfixExpression(Scope *S, ExprResult E,
 
 /// The set of properties that have already been added, referenced by
 /// property name.
-typedef llvm::SmallPtrSet<IdentifierInfo *, 16> AddedPropertiesSet;
+typedef llvm::SmallPtrSet<const IdentifierInfo *, 16> AddedPropertiesSet;
 
 /// Retrieve the container definition, if any?
 static ObjCContainerDecl *getContainerDef(ObjCContainerDecl *Container) {
@@ -5090,7 +5090,7 @@ AddObjCProperties(const CodeCompletionContext &CCContext,
     PrintingPolicy Policy = getCompletionPrintingPolicy(Results.getSema());
     // Adds a method result
     const auto AddMethod = [&](const ObjCMethodDecl *M) {
-      IdentifierInfo *Name = M->getSelector().getIdentifierInfoForSlot(0);
+      const IdentifierInfo *Name = M->getSelector().getIdentifierInfoForSlot(0);
       if (!Name)
         return;
       if (!AddedProperties.insert(Name).second)
@@ -5859,10 +5859,10 @@ void Sema::CodeCompleteMemberReferenceExpr(Scope *S, Expr *Base,
 }
 
 void Sema::CodeCompleteObjCClassPropertyRefExpr(Scope *S,
-                                                IdentifierInfo &ClassName,
+                                                const IdentifierInfo &ClassName,
                                                 SourceLocation ClassNameLoc,
                                                 bool IsBaseExprStatement) {
-  IdentifierInfo *ClassNamePtr = &ClassName;
+  const IdentifierInfo *ClassNamePtr = &ClassName;
   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(ClassNamePtr, ClassNameLoc);
   if (!IFace)
     return;
@@ -7527,7 +7527,7 @@ enum ObjCMethodKind {
 };
 
 static bool isAcceptableObjCSelector(Selector Sel, ObjCMethodKind WantKind,
-                                     ArrayRef<IdentifierInfo *> SelIdents,
+                                     ArrayRef<const IdentifierInfo *> SelIdents,
                                      bool AllowSameLength = true) {
   unsigned NumSelIdents = SelIdents.size();
   if (NumSelIdents > Sel.getNumArgs())
@@ -7554,7 +7554,7 @@ static bool isAcceptableObjCSelector(Selector Sel, ObjCMethodKind WantKind,
 
 static bool isAcceptableObjCMethod(ObjCMethodDecl *Method,
                                    ObjCMethodKind WantKind,
-                                   ArrayRef<IdentifierInfo *> SelIdents,
+                                   ArrayRef<const IdentifierInfo *> SelIdents,
                                    bool AllowSameLength = true) {
   return isAcceptableObjCSelector(Method->getSelector(), WantKind, SelIdents,
                                   AllowSameLength);
@@ -7586,7 +7586,7 @@ typedef llvm::SmallPtrSet<Selector, 16> VisitedSelectorSet;
 /// \param Results the structure into which we'll add results.
 static void AddObjCMethods(ObjCContainerDecl *Container,
                            bool WantInstanceMethods, ObjCMethodKind WantKind,
-                           ArrayRef<IdentifierInfo *> SelIdents,
+                           ArrayRef<const IdentifierInfo *> SelIdents,
                            DeclContext *CurContext,
                            VisitedSelectorSet &Selectors, bool AllowSameLength,
                            ResultBuilder &Results, bool InOriginalClass = true,
@@ -7819,7 +7819,7 @@ static ObjCInterfaceDecl *GetAssumedMessageSendExprType(Expr *E) {
   if (Sel.isNull())
     return nullptr;
 
-  IdentifierInfo *Id = Sel.getIdentifierInfoForSlot(0);
+  const IdentifierInfo *Id = Sel.getIdentifierInfoForSlot(0);
   if (!Id)
     return nullptr;
 
@@ -7895,7 +7895,7 @@ static ObjCInterfaceDecl *GetAssumedMessageSendExprType(Expr *E) {
 /// this "super" completion. If NULL, no completion was added.
 static ObjCMethodDecl *
 AddSuperSendCompletion(Sema &S, bool NeedSuperKeyword,
-                       ArrayRef<IdentifierInfo *> SelIdents,
+                       ArrayRef<const IdentifierInfo *> SelIdents,
                        ResultBuilder &Results) {
   ObjCMethodDecl *CurMethod = S.getCurMethodDecl();
   if (!CurMethod)
@@ -8032,9 +8032,9 @@ void Sema::CodeCompleteObjCMessageReceiver(Scope *S) {
                             Results.data(), Results.size());
 }
 
-void Sema::CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
-                                        ArrayRef<IdentifierInfo *> SelIdents,
-                                        bool AtArgumentExpression) {
+void Sema::CodeCompleteObjCSuperMessage(
+    Scope *S, SourceLocation SuperLoc,
+    ArrayRef<const IdentifierInfo *> SelIdents, bool AtArgumentExpression) {
   ObjCInterfaceDecl *CDecl = nullptr;
   if (ObjCMethodDecl *CurMethod = getCurMethodDecl()) {
     // Figure out which interface we're in.
@@ -8059,7 +8059,7 @@ void Sema::CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
   } else {
     // "super" may be the name of a type or variable. Figure out which
     // it is.
-    IdentifierInfo *Super = getSuperIdentifier();
+    const IdentifierInfo *Super = getSuperIdentifier();
     NamedDecl *ND = LookupSingleName(S, Super, SuperLoc, LookupOrdinaryName);
     if ((CDecl = dyn_cast_or_null<ObjCInterfaceDecl>(ND))) {
       // "super" names an interface. Use it.
@@ -8127,11 +8127,11 @@ static QualType getPreferredArgumentTypeForMessageSend(ResultBuilder &Results,
   return PreferredType;
 }
 
-static void AddClassMessageCompletions(Sema &SemaRef, Scope *S,
-                                       ParsedType Receiver,
-                                       ArrayRef<IdentifierInfo *> SelIdents,
-                                       bool AtArgumentExpression, bool IsSuper,
-                                       ResultBuilder &Results) {
+static void
+AddClassMessageCompletions(Sema &SemaRef, Scope *S, ParsedType Receiver,
+                           ArrayRef<const IdentifierInfo *> SelIdents,
+                           bool AtArgumentExpression, bool IsSuper,
+                           ResultBuilder &Results) {
   typedef CodeCompletionResult Result;
   ObjCInterfaceDecl *CDecl = nullptr;
 
@@ -8202,10 +8202,9 @@ static void AddClassMessageCompletions(Sema &SemaRef, Scope *S,
   Results.ExitScope();
 }
 
-void Sema::CodeCompleteObjCClassMessage(Scope *S, ParsedType Receiver,
-                                        ArrayRef<IdentifierInfo *> SelIdents,
-                                        bool AtArgumentExpression,
-                                        bool IsSuper) {
+void Sema::CodeCompleteObjCClassMessage(
+    Scope *S, ParsedType Receiver, ArrayRef<const IdentifierInfo *> SelIdents,
+    bool AtArgumentExpression, bool IsSuper) {
 
   QualType T = this->GetTypeFromParser(Receiver);
 
@@ -8237,10 +8236,9 @@ void Sema::CodeCompleteObjCClassMessage(Scope *S, ParsedType Receiver,
                             Results.data(), Results.size());
 }
 
-void Sema::CodeCompleteObjCInstanceMessage(Scope *S, Expr *Receiver,
-                                           ArrayRef<IdentifierInfo *> SelIdents,
-                                           bool AtArgumentExpression,
-                                           ObjCInterfaceDecl *Super) {
+void Sema::CodeCompleteObjCInstanceMessage(
+    Scope *S, Expr *Receiver, ArrayRef<const IdentifierInfo *> SelIdents,
+    bool AtArgumentExpression, ObjCInterfaceDecl *Super) {
   typedef CodeCompletionResult Result;
 
   Expr *RecExpr = static_cast<Expr *>(Receiver);
@@ -8410,8 +8408,8 @@ void Sema::CodeCompleteObjCForCollection(Scope *S,
   CodeCompleteExpression(S, Data);
 }
 
-void Sema::CodeCompleteObjCSelector(Scope *S,
-                                    ArrayRef<IdentifierInfo *> SelIdents) {
+void Sema::CodeCompleteObjCSelector(
+    Scope *S, ArrayRef<const IdentifierInfo *> SelIdents) {
   // If we have an external source, load the entire class method
   // pool from the AST file.
   if (ExternalSource) {
@@ -9166,8 +9164,8 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // Add -(void)getKey:(type **)buffer range:(NSRange)inRange
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("get") + UpperKey).str();
-    IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName),
-                                      &Context.Idents.get("range")};
+    const IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName),
+                                            &Context.Idents.get("range")};
 
     if (KnownSelectors.insert(Selectors.getSelector(2, SelectorIds)).second) {
       if (ReturnType.isNull()) {
@@ -9198,8 +9196,8 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // - (void)insertObject:(type *)object inKeyAtIndex:(NSUInteger)index
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("in") + UpperKey + "AtIndex").str();
-    IdentifierInfo *SelectorIds[2] = {&Context.Idents.get("insertObject"),
-                                      &Context.Idents.get(SelectorName)};
+    const IdentifierInfo *SelectorIds[2] = {&Context.Idents.get("insertObject"),
+                                            &Context.Idents.get(SelectorName)};
 
     if (KnownSelectors.insert(Selectors.getSelector(2, SelectorIds)).second) {
       if (ReturnType.isNull()) {
@@ -9228,8 +9226,8 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // - (void)insertKey:(NSArray *)array atIndexes:(NSIndexSet *)indexes
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("insert") + UpperKey).str();
-    IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName),
-                                      &Context.Idents.get("atIndexes")};
+    const IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName),
+                                            &Context.Idents.get("atIndexes")};
 
     if (KnownSelectors.insert(Selectors.getSelector(2, SelectorIds)).second) {
       if (ReturnType.isNull()) {
@@ -9258,7 +9256,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName =
         (Twine("removeObjectFrom") + UpperKey + "AtIndex").str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9279,7 +9277,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // -(void)removeKeyAtIndexes:(NSIndexSet *)indexes
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("remove") + UpperKey + "AtIndexes").str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9301,8 +9299,8 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName =
         (Twine("replaceObjectIn") + UpperKey + "AtIndex").str();
-    IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName),
-                                      &Context.Idents.get("withObject")};
+    const IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName),
+                                            &Context.Idents.get("withObject")};
 
     if (KnownSelectors.insert(Selectors.getSelector(2, SelectorIds)).second) {
       if (ReturnType.isNull()) {
@@ -9332,8 +9330,8 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
     std::string SelectorName1 =
         (Twine("replace") + UpperKey + "AtIndexes").str();
     std::string SelectorName2 = (Twine("with") + UpperKey).str();
-    IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName1),
-                                      &Context.Idents.get(SelectorName2)};
+    const IdentifierInfo *SelectorIds[2] = {&Context.Idents.get(SelectorName1),
+                                            &Context.Idents.get(SelectorName2)};
 
     if (KnownSelectors.insert(Selectors.getSelector(2, SelectorIds)).second) {
       if (ReturnType.isNull()) {
@@ -9368,7 +9366,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
                 ->getInterfaceDecl()
                 ->getName() == "NSEnumerator"))) {
     std::string SelectorName = (Twine("enumeratorOf") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getNullarySelector(SelectorId))
             .second) {
       if (ReturnType.isNull()) {
@@ -9387,7 +9385,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   if (IsInstanceMethod &&
       (ReturnType.isNull() || ReturnType->isObjCObjectPointerType())) {
     std::string SelectorName = (Twine("memberOf") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9417,7 +9415,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName =
         (Twine("add") + UpperKey + Twine("Object")).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9439,7 +9437,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // - (void)addKey:(NSSet *)objects
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("add") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9461,7 +9459,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName =
         (Twine("remove") + UpperKey + Twine("Object")).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9483,7 +9481,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // - (void)removeKey:(NSSet *)objects
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("remove") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9504,7 +9502,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
   // - (void)intersectKey:(NSSet *)objects
   if (IsInstanceMethod && ReturnTypeMatchesVoid) {
     std::string SelectorName = (Twine("intersect") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getUnarySelector(SelectorId)).second) {
       if (ReturnType.isNull()) {
         Builder.AddChunk(CodeCompletionString::CK_LeftParen);
@@ -9533,7 +9531,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
                 ->getName() == "NSSet"))) {
     std::string SelectorName =
         (Twine("keyPathsForValuesAffecting") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getNullarySelector(SelectorId))
             .second) {
       if (ReturnType.isNull()) {
@@ -9554,7 +9552,7 @@ static void AddObjCKeyValueCompletions(ObjCPropertyDecl *Property,
        ReturnType->isBooleanType())) {
     std::string SelectorName =
         (Twine("automaticallyNotifiesObserversOf") + UpperKey).str();
-    IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
+    const IdentifierInfo *SelectorId = &Context.Idents.get(SelectorName);
     if (KnownSelectors.insert(Selectors.getNullarySelector(SelectorId))
             .second) {
       if (ReturnType.isNull()) {
@@ -9749,7 +9747,7 @@ void Sema::CodeCompleteObjCMethodDecl(Scope *S,
 
 void Sema::CodeCompleteObjCMethodDeclSelector(
     Scope *S, bool IsInstanceMethod, bool AtParameterName, ParsedType ReturnTy,
-    ArrayRef<IdentifierInfo *> SelIdents) {
+    ArrayRef<const IdentifierInfo *> SelIdents) {
   // If we have an external source, load the entire class method
   // pool from the AST file.
   if (ExternalSource) {

diff  --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 8472aaeb6bad97..5a23179dfbbf44 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -2318,7 +2318,7 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
 ///
 /// \returns The declaration of the named Objective-C class, or NULL if the
 /// class could not be found.
-ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(IdentifierInfo *&Id,
+ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(const IdentifierInfo *&Id,
                                               SourceLocation IdLoc,
                                               bool DoTypoCorrection) {
   // The third "scope" argument is 0 since we aren't enabling lazy built-in
@@ -15307,7 +15307,7 @@ Decl *Sema::ActOnParamDeclarator(Scope *S, Declarator &D,
   QualType parmDeclType = TInfo->getType();
 
   // Check for redeclaration of parameters, e.g. int foo(int x, int x);
-  IdentifierInfo *II = D.getIdentifier();
+  const IdentifierInfo *II = D.getIdentifier();
   if (II) {
     LookupResult R(*this, II, D.getIdentifierLoc(), LookupOrdinaryName,
                    ForVisibleRedeclaration);
@@ -15459,9 +15459,9 @@ QualType Sema::AdjustParameterTypeForObjCAutoRefCount(QualType T,
 }
 
 ParmVarDecl *Sema::CheckParameter(DeclContext *DC, SourceLocation StartLoc,
-                                  SourceLocation NameLoc, IdentifierInfo *Name,
-                                  QualType T, TypeSourceInfo *TSInfo,
-                                  StorageClass SC) {
+                                  SourceLocation NameLoc,
+                                  const IdentifierInfo *Name, QualType T,
+                                  TypeSourceInfo *TSInfo, StorageClass SC) {
   // In ARC, infer a lifetime qualifier for appropriate parameter types.
   if (getLangOpts().ObjCAutoRefCount &&
       T.getObjCLifetime() == Qualifiers::OCL_None &&
@@ -18551,8 +18551,9 @@ void Sema::ActOnTagDefinitionError(Scope *S, Decl *TagD) {
 
 // Note that FieldName may be null for anonymous bitfields.
 ExprResult Sema::VerifyBitField(SourceLocation FieldLoc,
-                                IdentifierInfo *FieldName, QualType FieldTy,
-                                bool IsMsStruct, Expr *BitWidth) {
+                                const IdentifierInfo *FieldName,
+                                QualType FieldTy, bool IsMsStruct,
+                                Expr *BitWidth) {
   assert(BitWidth);
   if (BitWidth->containsErrors())
     return ExprError();
@@ -18661,7 +18662,7 @@ FieldDecl *Sema::HandleField(Scope *S, RecordDecl *Record,
     return nullptr;
   }
 
-  IdentifierInfo *II = D.getIdentifier();
+  const IdentifierInfo *II = D.getIdentifier();
   SourceLocation Loc = DeclStart;
   if (II) Loc = D.getIdentifierLoc();
 
@@ -18762,7 +18763,7 @@ FieldDecl *Sema::CheckFieldDecl(DeclarationName Name, QualType T,
                                 SourceLocation TSSL,
                                 AccessSpecifier AS, NamedDecl *PrevDecl,
                                 Declarator *D) {
-  IdentifierInfo *II = Name.getAsIdentifierInfo();
+  const IdentifierInfo *II = Name.getAsIdentifierInfo();
   bool InvalidDecl = false;
   if (D) InvalidDecl = D->isInvalidType();
 
@@ -19022,7 +19023,7 @@ TranslateIvarVisibility(tok::ObjCKeywordKind ivarVisibility) {
 Decl *Sema::ActOnIvar(Scope *S, SourceLocation DeclStart, Declarator &D,
                       Expr *BitWidth, tok::ObjCKeywordKind Visibility) {
 
-  IdentifierInfo *II = D.getIdentifier();
+  const IdentifierInfo *II = D.getIdentifier();
   SourceLocation Loc = DeclStart;
   if (II) Loc = D.getIdentifierLoc();
 

diff  --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 068a2e4f04fa50..858951580ea45b 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -16913,11 +16913,10 @@ Decl *Sema::ActOnEmptyDeclaration(Scope *S,
 /// Perform semantic analysis for the variable declaration that
 /// occurs within a C++ catch clause, returning the newly-created
 /// variable.
-VarDecl *Sema::BuildExceptionDeclaration(Scope *S,
-                                         TypeSourceInfo *TInfo,
+VarDecl *Sema::BuildExceptionDeclaration(Scope *S, TypeSourceInfo *TInfo,
                                          SourceLocation StartLoc,
                                          SourceLocation Loc,
-                                         IdentifierInfo *Name) {
+                                         const IdentifierInfo *Name) {
   bool Invalid = false;
   QualType ExDeclType = TInfo->getType();
 
@@ -17062,7 +17061,7 @@ Decl *Sema::ActOnExceptionDeclarator(Scope *S, Declarator &D) {
     Invalid = true;
   }
 
-  IdentifierInfo *II = D.getIdentifier();
+  const IdentifierInfo *II = D.getIdentifier();
   if (NamedDecl *PrevDecl = LookupSingleName(S, II, D.getIdentifierLoc(),
                                              LookupOrdinaryName,
                                              ForVisibleRedeclaration)) {
@@ -19158,7 +19157,7 @@ MSPropertyDecl *Sema::HandleMSProperty(Scope *S, RecordDecl *Record,
                                        InClassInitStyle InitStyle,
                                        AccessSpecifier AS,
                                        const ParsedAttr &MSPropertyAttr) {
-  IdentifierInfo *II = D.getIdentifier();
+  const IdentifierInfo *II = D.getIdentifier();
   if (!II) {
     Diag(DeclStart, diag::err_anonymous_property);
     return nullptr;

diff  --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 94a245f0f905f3..74d6f0700b0e4f 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -1818,9 +1818,9 @@ Sema::ActOnForwardProtocolDeclaration(SourceLocation AtProtocolLoc,
 }
 
 ObjCCategoryDecl *Sema::ActOnStartCategoryInterface(
-    SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
+    SourceLocation AtInterfaceLoc, const IdentifierInfo *ClassName,
     SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
-    IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
+    const IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
     Decl *const *ProtoRefs, unsigned NumProtoRefs,
     const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
     const ParsedAttributesView &AttrList) {
@@ -1916,9 +1916,9 @@ ObjCCategoryDecl *Sema::ActOnStartCategoryInterface(
 /// category implementation declaration and build an ObjCCategoryImplDecl
 /// object.
 ObjCCategoryImplDecl *Sema::ActOnStartCategoryImplementation(
-    SourceLocation AtCatImplLoc, IdentifierInfo *ClassName,
-    SourceLocation ClassLoc, IdentifierInfo *CatName, SourceLocation CatLoc,
-    const ParsedAttributesView &Attrs) {
+    SourceLocation AtCatImplLoc, const IdentifierInfo *ClassName,
+    SourceLocation ClassLoc, const IdentifierInfo *CatName,
+    SourceLocation CatLoc, const ParsedAttributesView &Attrs) {
   ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(ClassName, ClassLoc, true);
   ObjCCategoryDecl *CatIDecl = nullptr;
   if (IDecl && IDecl->hasDefinition()) {
@@ -1982,8 +1982,8 @@ ObjCCategoryImplDecl *Sema::ActOnStartCategoryImplementation(
 }
 
 ObjCImplementationDecl *Sema::ActOnStartClassImplementation(
-    SourceLocation AtClassImplLoc, IdentifierInfo *ClassName,
-    SourceLocation ClassLoc, IdentifierInfo *SuperClassname,
+    SourceLocation AtClassImplLoc, const IdentifierInfo *ClassName,
+    SourceLocation ClassLoc, const IdentifierInfo *SuperClassname,
     SourceLocation SuperClassLoc, const ParsedAttributesView &Attrs) {
   ObjCInterfaceDecl *IDecl = nullptr;
   // Check for another declaration kind with the same name.
@@ -2751,7 +2751,7 @@ static void CheckProtocolMethodDefs(
     // implemented in the class, we should not issue "Method definition not
     // found" warnings.
     // FIXME: Use a general GetUnarySelector method for this.
-    IdentifierInfo* II = &S.Context.Idents.get("forwardInvocation");
+    const IdentifierInfo *II = &S.Context.Idents.get("forwardInvocation");
     Selector fISelector = S.Context.Selectors.getSelector(1, &II);
     if (InsMap.count(fISelector))
       // Is IDecl derived from 'NSProxy'? If so, no instance methods
@@ -5105,8 +5105,8 @@ bool Sema::CheckObjCDeclScope(Decl *D) {
 /// Called whenever \@defs(ClassName) is encountered in the source.  Inserts the
 /// instance variables of ClassName into Decls.
 void Sema::ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
-                     IdentifierInfo *ClassName,
-                     SmallVectorImpl<Decl*> &Decls) {
+                     const IdentifierInfo *ClassName,
+                     SmallVectorImpl<Decl *> &Decls) {
   // Check that ClassName is a valid class
   ObjCInterfaceDecl *Class = getObjCInterfaceDecl(ClassName, DeclStart);
   if (!Class) {
@@ -5148,8 +5148,7 @@ void Sema::ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
 VarDecl *Sema::BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType T,
                                       SourceLocation StartLoc,
                                       SourceLocation IdLoc,
-                                      IdentifierInfo *Id,
-                                      bool Invalid) {
+                                      const IdentifierInfo *Id, bool Invalid) {
   // ISO/IEC TR 18037 S6.7.3: "The type of an object with automatic storage
   // duration shall not be qualified by an address-space qualifier."
   // Since all parameters have automatic store duration, they can not have

diff  --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 7b9b8f149d9edd..12f42f66e5e21b 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -57,7 +57,7 @@ using namespace sema;
 /// name of the corresponding type.
 ParsedType Sema::getInheritingConstructorName(CXXScopeSpec &SS,
                                               SourceLocation NameLoc,
-                                              IdentifierInfo &Name) {
+                                              const IdentifierInfo &Name) {
   NestedNameSpecifier *NNS = SS.getScopeRep();
 
   // Convert the nested-name-specifier into a type.
@@ -89,10 +89,9 @@ ParsedType Sema::getInheritingConstructorName(CXXScopeSpec &SS,
                           Context.getTrivialTypeSourceInfo(Type, NameLoc));
 }
 
-ParsedType Sema::getConstructorName(IdentifierInfo &II,
-                                    SourceLocation NameLoc,
-                                    Scope *S, CXXScopeSpec &SS,
-                                    bool EnteringContext) {
+ParsedType Sema::getConstructorName(const IdentifierInfo &II,
+                                    SourceLocation NameLoc, Scope *S,
+                                    CXXScopeSpec &SS, bool EnteringContext) {
   CXXRecordDecl *CurClass = getCurrentClass(S, &SS);
   assert(CurClass && &II == CurClass->getIdentifier() &&
          "not a constructor name");
@@ -140,9 +139,9 @@ ParsedType Sema::getConstructorName(IdentifierInfo &II,
   return ParsedType::make(T);
 }
 
-ParsedType Sema::getDestructorName(IdentifierInfo &II, SourceLocation NameLoc,
-                                   Scope *S, CXXScopeSpec &SS,
-                                   ParsedType ObjectTypePtr,
+ParsedType Sema::getDestructorName(const IdentifierInfo &II,
+                                   SourceLocation NameLoc, Scope *S,
+                                   CXXScopeSpec &SS, ParsedType ObjectTypePtr,
                                    bool EnteringContext) {
   // Determine where to perform name lookup.
 
@@ -500,7 +499,7 @@ bool Sema::checkLiteralOperatorId(const CXXScopeSpec &SS,
     //
     // double operator""_Bq(long double);  // OK: not a reserved identifier
     // double operator"" _Bq(long double); // ill-formed, no diagnostic required
-    IdentifierInfo *II = Name.Identifier;
+    const IdentifierInfo *II = Name.Identifier;
     ReservedIdentifierStatus Status = II->isReserved(PP.getLangOpts());
     SourceLocation Loc = Name.getEndLoc();
     if (!PP.getSourceManager().isInSystemHeader(Loc)) {
@@ -9178,10 +9177,9 @@ concepts::Requirement *Sema::ActOnSimpleRequirement(Expr *E) {
                               /*ReturnTypeRequirement=*/{});
 }
 
-concepts::Requirement *
-Sema::ActOnTypeRequirement(SourceLocation TypenameKWLoc, CXXScopeSpec &SS,
-                           SourceLocation NameLoc, IdentifierInfo *TypeName,
-                           TemplateIdAnnotation *TemplateId) {
+concepts::Requirement *Sema::ActOnTypeRequirement(
+    SourceLocation TypenameKWLoc, CXXScopeSpec &SS, SourceLocation NameLoc,
+    const IdentifierInfo *TypeName, TemplateIdAnnotation *TemplateId) {
   assert(((!TypeName && TemplateId) || (TypeName && !TemplateId)) &&
          "Exactly one of TypeName and TemplateId must be specified.");
   TypeSourceInfo *TSI = nullptr;

diff  --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index a8853f634c9cc9..3148f0db6e20c8 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -663,10 +663,8 @@ ExprResult Sema::BuildObjCBoxedExpr(SourceRange SR, Expr *ValueExpr) {
     }
 
     if (!ValueWithBytesObjCTypeMethod) {
-      IdentifierInfo *II[] = {
-        &Context.Idents.get("valueWithBytes"),
-        &Context.Idents.get("objCType")
-      };
+      const IdentifierInfo *II[] = {&Context.Idents.get("valueWithBytes"),
+                                    &Context.Idents.get("objCType")};
       Selector ValueWithBytesObjCType = Context.Selectors.getSelector(2, II);
 
       // Look for the appropriate method within NSValue.
@@ -2155,13 +2153,12 @@ HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
   return ExprError();
 }
 
-ExprResult Sema::
-ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
-                          IdentifierInfo &propertyName,
-                          SourceLocation receiverNameLoc,
-                          SourceLocation propertyNameLoc) {
+ExprResult Sema::ActOnClassPropertyRefExpr(const IdentifierInfo &receiverName,
+                                           const IdentifierInfo &propertyName,
+                                           SourceLocation receiverNameLoc,
+                                           SourceLocation propertyNameLoc) {
 
-  IdentifierInfo *receiverNamePtr = &receiverName;
+  const IdentifierInfo *receiverNamePtr = &receiverName;
   ObjCInterfaceDecl *IFace = getObjCInterfaceDecl(receiverNamePtr,
                                                   receiverNameLoc);
 

diff  --git a/clang/lib/Sema/SemaObjCProperty.cpp b/clang/lib/Sema/SemaObjCProperty.cpp
index f9e1ad0121e2a2..222a65a13dd0b2 100644
--- a/clang/lib/Sema/SemaObjCProperty.cpp
+++ b/clang/lib/Sema/SemaObjCProperty.cpp
@@ -419,7 +419,7 @@ Sema::HandlePropertyInClassExtension(Scope *S,
   ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
   // Diagnose if this property is already in continuation class.
   DeclContext *DC = CurContext;
-  IdentifierInfo *PropertyId = FD.D.getIdentifier();
+  const IdentifierInfo *PropertyId = FD.D.getIdentifier();
   ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();
 
   // We need to look in the @interface to see if the @property was
@@ -571,7 +571,7 @@ ObjCPropertyDecl *Sema::CreatePropertyDecl(Scope *S,
                                            TypeSourceInfo *TInfo,
                                            tok::ObjCKeywordKind MethodImplKind,
                                            DeclContext *lexicalDC){
-  IdentifierInfo *PropertyId = FD.D.getIdentifier();
+  const IdentifierInfo *PropertyId = FD.D.getIdentifier();
 
   // Property defaults to 'assign' if it is readwrite, unless this is ARC
   // and the type is retainable.

diff  --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index c814535ad6bdb7..e9efb4721133fe 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -7375,7 +7375,7 @@ void Sema::ActOnStartOfFunctionDefinitionInOpenMPDeclareVariantScope(
           llvm::omp::TraitProperty::implementation_extension_allow_templates))
     return;
 
-  IdentifierInfo *BaseII = D.getIdentifier();
+  const IdentifierInfo *BaseII = D.getIdentifier();
   LookupResult Lookup(*this, DeclarationName(BaseII), D.getIdentifierLoc(),
                       LookupOrdinaryName);
   LookupParsedName(Lookup, S, &D.getCXXScopeSpec());

diff  --git a/clang/lib/Sema/SemaPseudoObject.cpp b/clang/lib/Sema/SemaPseudoObject.cpp
index 528c261c4a297f..82774760b34d44 100644
--- a/clang/lib/Sema/SemaPseudoObject.cpp
+++ b/clang/lib/Sema/SemaPseudoObject.cpp
@@ -613,9 +613,9 @@ bool ObjCPropertyOpBuilder::findGetter() {
       // Must build the getter selector the hard way.
       ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter();
       assert(setter && "both setter and getter are null - cannot happen");
-      IdentifierInfo *setterName =
-        setter->getSelector().getIdentifierInfoForSlot(0);
-      IdentifierInfo *getterName =
+      const IdentifierInfo *setterName =
+          setter->getSelector().getIdentifierInfoForSlot(0);
+      const IdentifierInfo *getterName =
           &S.Context.Idents.get(setterName->getName().substr(3));
       GetterSelector =
         S.PP.getSelectorTable().getNullarySelector(getterName);
@@ -640,9 +640,9 @@ bool ObjCPropertyOpBuilder::findSetter(bool warn) {
       SetterSelector = setter->getSelector();
       return true;
     } else {
-      IdentifierInfo *getterName =
-        RefExpr->getImplicitPropertyGetter()->getSelector()
-          .getIdentifierInfoForSlot(0);
+      const IdentifierInfo *getterName = RefExpr->getImplicitPropertyGetter()
+                                             ->getSelector()
+                                             .getIdentifierInfoForSlot(0);
       SetterSelector =
         SelectorTable::constructSetterSelector(S.PP.getIdentifierTable(),
                                                S.PP.getSelectorTable(),
@@ -667,7 +667,8 @@ bool ObjCPropertyOpBuilder::findSetter(bool warn) {
         front = isLowercase(front) ? toUppercase(front) : toLowercase(front);
         SmallString<100> PropertyName = thisPropertyName;
         PropertyName[0] = front;
-        IdentifierInfo *AltMember = &S.PP.getIdentifierTable().get(PropertyName);
+        const IdentifierInfo *AltMember =
+            &S.PP.getIdentifierTable().get(PropertyName);
         if (ObjCPropertyDecl *prop1 = IFace->FindPropertyDeclaration(
                 AltMember, prop->getQueryKind()))
           if (prop != prop1 && (prop1->getSetterMethodDecl() == setter)) {
@@ -1126,9 +1127,8 @@ static void CheckKeyForObjCARCConversion(Sema &S, QualType ContainerT,
     return;
   // dictionary subscripting.
   // - (id)objectForKeyedSubscript:(id)key;
-  IdentifierInfo *KeyIdents[] = {
-    &S.Context.Idents.get("objectForKeyedSubscript")
-  };
+  const IdentifierInfo *KeyIdents[] = {
+      &S.Context.Idents.get("objectForKeyedSubscript")};
   Selector GetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
   ObjCMethodDecl *Getter = S.LookupMethodInObjectType(GetterSelector, ContainerT,
                                                       true /*instance*/);
@@ -1169,16 +1169,14 @@ bool ObjCSubscriptOpBuilder::findAtIndexGetter() {
   if (!arrayRef) {
     // dictionary subscripting.
     // - (id)objectForKeyedSubscript:(id)key;
-    IdentifierInfo *KeyIdents[] = {
-      &S.Context.Idents.get("objectForKeyedSubscript")
-    };
+    const IdentifierInfo *KeyIdents[] = {
+        &S.Context.Idents.get("objectForKeyedSubscript")};
     AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
   }
   else {
     // - (id)objectAtIndexedSubscript:(size_t)index;
-    IdentifierInfo *KeyIdents[] = {
-      &S.Context.Idents.get("objectAtIndexedSubscript")
-    };
+    const IdentifierInfo *KeyIdents[] = {
+        &S.Context.Idents.get("objectAtIndexedSubscript")};
 
     AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
   }
@@ -1274,18 +1272,16 @@ bool ObjCSubscriptOpBuilder::findAtIndexSetter() {
   if (!arrayRef) {
     // dictionary subscripting.
     // - (void)setObject:(id)object forKeyedSubscript:(id)key;
-    IdentifierInfo *KeyIdents[] = {
-      &S.Context.Idents.get("setObject"),
-      &S.Context.Idents.get("forKeyedSubscript")
-    };
+    const IdentifierInfo *KeyIdents[] = {
+        &S.Context.Idents.get("setObject"),
+        &S.Context.Idents.get("forKeyedSubscript")};
     AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
   }
   else {
     // - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
-    IdentifierInfo *KeyIdents[] = {
-      &S.Context.Idents.get("setObject"),
-      &S.Context.Idents.get("atIndexedSubscript")
-    };
+    const IdentifierInfo *KeyIdents[] = {
+        &S.Context.Idents.get("setObject"),
+        &S.Context.Idents.get("atIndexedSubscript")};
     AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
   }
   AtIndexSetter = S.LookupMethodInObjectType(AtIndexSetterSelector, ResultType,
@@ -1474,7 +1470,7 @@ ExprResult MSPropertyOpBuilder::buildGet() {
   }
 
   UnqualifiedId GetterName;
-  IdentifierInfo *II = RefExpr->getPropertyDecl()->getGetterId();
+  const IdentifierInfo *II = RefExpr->getPropertyDecl()->getGetterId();
   GetterName.setIdentifier(II, RefExpr->getMemberLoc());
   CXXScopeSpec SS;
   SS.Adopt(RefExpr->getQualifierLoc());
@@ -1503,7 +1499,7 @@ ExprResult MSPropertyOpBuilder::buildSet(Expr *op, SourceLocation sl,
   }
 
   UnqualifiedId SetterName;
-  IdentifierInfo *II = RefExpr->getPropertyDecl()->getSetterId();
+  const IdentifierInfo *II = RefExpr->getPropertyDecl()->getSetterId();
   SetterName.setIdentifier(II, RefExpr->getMemberLoc());
   CXXScopeSpec SS;
   SS.Adopt(RefExpr->getQualifierLoc());

diff  --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index e72397adec24fb..e53c76e65b03d2 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -2275,11 +2275,9 @@ Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
     // Otherwise, if we have any useful type information, check that
     // the type declares the appropriate method.
   } else if (iface || !objectType->qual_empty()) {
-    IdentifierInfo *selectorIdents[] = {
-      &Context.Idents.get("countByEnumeratingWithState"),
-      &Context.Idents.get("objects"),
-      &Context.Idents.get("count")
-    };
+    const IdentifierInfo *selectorIdents[] = {
+        &Context.Idents.get("countByEnumeratingWithState"),
+        &Context.Idents.get("objects"), &Context.Idents.get("count")};
     Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
 
     ObjCMethodDecl *method = nullptr;

diff  --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 2013799b5eb816..951e5a31cab3b8 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -970,7 +970,7 @@ void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
 
 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
                                                  SourceLocation Loc,
-                                                 IdentifierInfo *Name) {
+                                                 const IdentifierInfo *Name) {
   NamedDecl *PrevDecl = SemaRef.LookupSingleName(
       S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
   if (PrevDecl && PrevDecl->isTemplateParameter())
@@ -1578,7 +1578,7 @@ NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
 
   CheckFunctionOrTemplateParamDeclarator(S, D);
 
-  IdentifierInfo *ParamName = D.getIdentifier();
+  const IdentifierInfo *ParamName = D.getIdentifier();
   bool IsParameterPack = D.hasEllipsis();
   NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
       Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
@@ -4702,7 +4702,7 @@ bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
 
 TypeResult Sema::ActOnTemplateIdType(
     Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
-    TemplateTy TemplateD, IdentifierInfo *TemplateII,
+    TemplateTy TemplateD, const IdentifierInfo *TemplateII,
     SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
     ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
     bool IsCtorOrDtorName, bool IsClassName,
@@ -9684,10 +9684,9 @@ Decl *Sema::ActOnTemplateDeclarator(Scope *S,
   return NewDecl;
 }
 
-Decl *Sema::ActOnConceptDefinition(Scope *S,
-                              MultiTemplateParamsArg TemplateParameterLists,
-                                   IdentifierInfo *Name, SourceLocation NameLoc,
-                                   Expr *ConstraintExpr) {
+Decl *Sema::ActOnConceptDefinition(
+    Scope *S, MultiTemplateParamsArg TemplateParameterLists,
+    const IdentifierInfo *Name, SourceLocation NameLoc, Expr *ConstraintExpr) {
   DeclContext *DC = CurContext;
 
   if (!DC->getRedeclContext()->isFileContext()) {
@@ -11511,10 +11510,11 @@ DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
   return (Decl*) nullptr;
 }
 
-TypeResult
-Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
-                        const CXXScopeSpec &SS, IdentifierInfo *Name,
-                        SourceLocation TagLoc, SourceLocation NameLoc) {
+TypeResult Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
+                                   const CXXScopeSpec &SS,
+                                   const IdentifierInfo *Name,
+                                   SourceLocation TagLoc,
+                                   SourceLocation NameLoc) {
   // This has to hold, because SS is expected to be defined.
   assert(Name && "Expected a name in a dependent tag");
 
@@ -11574,14 +11574,10 @@ TypeResult Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
 }
 
 TypeResult
-Sema::ActOnTypenameType(Scope *S,
-                        SourceLocation TypenameLoc,
-                        const CXXScopeSpec &SS,
-                        SourceLocation TemplateKWLoc,
-                        TemplateTy TemplateIn,
-                        IdentifierInfo *TemplateII,
-                        SourceLocation TemplateIILoc,
-                        SourceLocation LAngleLoc,
+Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
+                        const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
+                        TemplateTy TemplateIn, const IdentifierInfo *TemplateII,
+                        SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
                         ASTTemplateArgsPtr TemplateArgsIn,
                         SourceLocation RAngleLoc) {
   if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
@@ -11657,7 +11653,6 @@ Sema::ActOnTypenameType(Scope *S,
   return CreateParsedType(T, TSI);
 }
 
-
 /// Determine whether this failed name lookup should be treated as being
 /// disabled by a usage of std::enable_if.
 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,

diff  --git a/clang/lib/Serialization/ASTCommon.cpp b/clang/lib/Serialization/ASTCommon.cpp
index 6110e287b7fb50..f8d54c0c398906 100644
--- a/clang/lib/Serialization/ASTCommon.cpp
+++ b/clang/lib/Serialization/ASTCommon.cpp
@@ -284,7 +284,7 @@ unsigned serialization::ComputeHash(Selector Sel) {
     ++N;
   unsigned R = 5381;
   for (unsigned I = 0; I != N; ++I)
-    if (IdentifierInfo *II = Sel.getIdentifierInfoForSlot(I))
+    if (const IdentifierInfo *II = Sel.getIdentifierInfoForSlot(I))
       R = llvm::djbHash(II->getName(), R);
   return R;
 }

diff  --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 0ca7f6600eee33..4f6987f92fc82e 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -916,14 +916,14 @@ ASTSelectorLookupTrait::ReadKey(const unsigned char* d, unsigned) {
   SelectorTable &SelTable = Reader.getContext().Selectors;
   unsigned N =
       endian::readNext<uint16_t, llvm::endianness::little, unaligned>(d);
-  IdentifierInfo *FirstII = Reader.getLocalIdentifier(
+  const IdentifierInfo *FirstII = Reader.getLocalIdentifier(
       F, endian::readNext<uint32_t, llvm::endianness::little, unaligned>(d));
   if (N == 0)
     return SelTable.getNullarySelector(FirstII);
   else if (N == 1)
     return SelTable.getUnarySelector(FirstII);
 
-  SmallVector<IdentifierInfo *, 16> Args;
+  SmallVector<const IdentifierInfo *, 16> Args;
   Args.push_back(FirstII);
   for (unsigned I = 1; I != N; ++I)
     Args.push_back(Reader.getLocalIdentifier(
@@ -987,7 +987,7 @@ ASTIdentifierLookupTraitBase::ReadKey(const unsigned char* d, unsigned n) {
 }
 
 /// Whether the given identifier is "interesting".
-static bool isInterestingIdentifier(ASTReader &Reader, IdentifierInfo &II,
+static bool isInterestingIdentifier(ASTReader &Reader, const IdentifierInfo &II,
                                     bool IsModule) {
   bool IsInteresting =
       II.getNotableIdentifierID() != tok::NotableIdentifierKind::not_notable ||
@@ -2229,7 +2229,7 @@ namespace {
 
 } // namespace
 
-void ASTReader::updateOutOfDateIdentifier(IdentifierInfo &II) {
+void ASTReader::updateOutOfDateIdentifier(const IdentifierInfo &II) {
   // Note that we are loading an identifier.
   Deserializing AnIdentifier(this);
 
@@ -2254,11 +2254,11 @@ void ASTReader::updateOutOfDateIdentifier(IdentifierInfo &II) {
   markIdentifierUpToDate(&II);
 }
 
-void ASTReader::markIdentifierUpToDate(IdentifierInfo *II) {
+void ASTReader::markIdentifierUpToDate(const IdentifierInfo *II) {
   if (!II)
     return;
 
-  II->setOutOfDate(false);
+  const_cast<IdentifierInfo *>(II)->setOutOfDate(false);
 
   // Update the generation for this identifier.
   if (getContext().getLangOpts().Modules)
@@ -10168,7 +10168,7 @@ void ASTReader::FinishedDeserializing() {
 }
 
 void ASTReader::pushExternalDeclIntoScope(NamedDecl *D, DeclarationName Name) {
-  if (IdentifierInfo *II = Name.getAsIdentifierInfo()) {
+  if (const IdentifierInfo *II = Name.getAsIdentifierInfo()) {
     // Remove any fake results before adding any real ones.
     auto It = PendingFakeLookupResults.find(II);
     if (It != PendingFakeLookupResults.end()) {

diff  --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index d2afe378bb0c33..ffc53292e39124 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3629,7 +3629,7 @@ class ASTIdentifierTableTrait {
   }
 
 public:
-  using key_type = IdentifierInfo *;
+  using key_type = const IdentifierInfo *;
   using key_type_ref = key_type;
 
   using data_type = IdentID;
@@ -3661,7 +3661,7 @@ class ASTIdentifierTableTrait {
   }
 
   std::pair<unsigned, unsigned>
-  EmitKeyDataLength(raw_ostream& Out, IdentifierInfo* II, IdentID ID) {
+  EmitKeyDataLength(raw_ostream &Out, const IdentifierInfo *II, IdentID ID) {
     // Record the location of the identifier data. This is used when generating
     // the mapping from persistent IDs to strings.
     Writer.SetIdentifierOffset(II, Out.tell());
@@ -3688,13 +3688,12 @@ class ASTIdentifierTableTrait {
     return emitULEBKeyDataLength(KeyLen, DataLen, Out);
   }
 
-  void EmitKey(raw_ostream& Out, const IdentifierInfo* II,
-               unsigned KeyLen) {
+  void EmitKey(raw_ostream &Out, const IdentifierInfo *II, unsigned KeyLen) {
     Out.write(II->getNameStart(), KeyLen);
   }
 
-  void EmitData(raw_ostream& Out, IdentifierInfo* II,
-                IdentID ID, unsigned) {
+  void EmitData(raw_ostream &Out, const IdentifierInfo *II, IdentID ID,
+                unsigned) {
     using namespace llvm::support;
 
     endian::Writer LE(Out, llvm::endianness::little);
@@ -3776,13 +3775,14 @@ void ASTWriter::WriteIdentifierTable(Preprocessor &PP,
     // for identifiers that appear here for the first time.
     IdentifierOffsets.resize(NextIdentID - FirstIdentID);
     for (auto IdentIDPair : IdentifierIDs) {
-      auto *II = const_cast<IdentifierInfo *>(IdentIDPair.first);
+      const IdentifierInfo *II = IdentIDPair.first;
       IdentID ID = IdentIDPair.second;
       assert(II && "NULL identifier in identifier table");
+
       // Write out identifiers if either the ID is local or the identifier has
       // changed since it was loaded.
-      if (ID >= FirstIdentID || !Chain || !II->isFromAST()
-          || II->hasChangedSinceDeserialization() ||
+      if (ID >= FirstIdentID || !Chain || !II->isFromAST() ||
+          II->hasChangedSinceDeserialization() ||
           (Trait.needDecls() &&
            II->hasFETokenInfoChangedSinceDeserialization()))
         Generator.insert(II, ID, Trait);

diff  --git a/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp b/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
index 978bc0bb082f80..b4390f0b85bbed 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
@@ -768,8 +768,8 @@ void ObjCDeallocChecker::initIdentifierInfoAndSelectors(
   Block_releaseII = &Ctx.Idents.get("_Block_release");
   CIFilterII = &Ctx.Idents.get("CIFilter");
 
-  IdentifierInfo *DeallocII = &Ctx.Idents.get("dealloc");
-  IdentifierInfo *ReleaseII = &Ctx.Idents.get("release");
+  const IdentifierInfo *DeallocII = &Ctx.Idents.get("dealloc");
+  const IdentifierInfo *ReleaseII = &Ctx.Idents.get("release");
   DeallocSel = Ctx.Selectors.getSelector(0, &DeallocII);
   ReleaseSel = Ctx.Selectors.getSelector(0, &ReleaseII);
 }

diff  --git a/clang/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
index 812d787e2e37c4..882eb0236a1896 100644
--- a/clang/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
@@ -154,11 +154,11 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UISearchDisplayController, setSearchResultsTitle, 0)
 
   NEW_RECEIVER(UITabBarItem)
-  IdentifierInfo *initWithTitleUITabBarItemTag[] = {
+  const IdentifierInfo *initWithTitleUITabBarItemTag[] = {
       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("image"),
       &Ctx.Idents.get("tag")};
   ADD_METHOD(UITabBarItem, initWithTitleUITabBarItemTag, 3, 0)
-  IdentifierInfo *initWithTitleUITabBarItemImage[] = {
+  const IdentifierInfo *initWithTitleUITabBarItemImage[] = {
       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("image"),
       &Ctx.Idents.get("selectedImage")};
   ADD_METHOD(UITabBarItem, initWithTitleUITabBarItemImage, 3, 0)
@@ -171,7 +171,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSStatusItem, setToolTip, 0)
 
   NEW_RECEIVER(UITableViewRowAction)
-  IdentifierInfo *rowActionWithStyleUITableViewRowAction[] = {
+  const IdentifierInfo *rowActionWithStyleUITableViewRowAction[] = {
       &Ctx.Idents.get("rowActionWithStyle"), &Ctx.Idents.get("title"),
       &Ctx.Idents.get("handler")};
   ADD_METHOD(UITableViewRowAction, rowActionWithStyleUITableViewRowAction, 3, 1)
@@ -183,19 +183,19 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   NEW_RECEIVER(NSButton)
   ADD_UNARY_METHOD(NSButton, setTitle, 0)
   ADD_UNARY_METHOD(NSButton, setAlternateTitle, 0)
-  IdentifierInfo *radioButtonWithTitleNSButton[] = {
+  const IdentifierInfo *radioButtonWithTitleNSButton[] = {
       &Ctx.Idents.get("radioButtonWithTitle"), &Ctx.Idents.get("target"),
       &Ctx.Idents.get("action")};
   ADD_METHOD(NSButton, radioButtonWithTitleNSButton, 3, 0)
-  IdentifierInfo *buttonWithTitleNSButtonImage[] = {
+  const IdentifierInfo *buttonWithTitleNSButtonImage[] = {
       &Ctx.Idents.get("buttonWithTitle"), &Ctx.Idents.get("image"),
       &Ctx.Idents.get("target"), &Ctx.Idents.get("action")};
   ADD_METHOD(NSButton, buttonWithTitleNSButtonImage, 4, 0)
-  IdentifierInfo *checkboxWithTitleNSButton[] = {
+  const IdentifierInfo *checkboxWithTitleNSButton[] = {
       &Ctx.Idents.get("checkboxWithTitle"), &Ctx.Idents.get("target"),
       &Ctx.Idents.get("action")};
   ADD_METHOD(NSButton, checkboxWithTitleNSButton, 3, 0)
-  IdentifierInfo *buttonWithTitleNSButtonTarget[] = {
+  const IdentifierInfo *buttonWithTitleNSButtonTarget[] = {
       &Ctx.Idents.get("buttonWithTitle"), &Ctx.Idents.get("target"),
       &Ctx.Idents.get("action")};
   ADD_METHOD(NSButton, buttonWithTitleNSButtonTarget, 3, 0)
@@ -215,8 +215,8 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSTabViewItem, setToolTip, 0)
 
   NEW_RECEIVER(NSBrowser)
-  IdentifierInfo *setTitleNSBrowser[] = {&Ctx.Idents.get("setTitle"),
-                                         &Ctx.Idents.get("ofColumn")};
+  const IdentifierInfo *setTitleNSBrowser[] = {&Ctx.Idents.get("setTitle"),
+                                               &Ctx.Idents.get("ofColumn")};
   ADD_METHOD(NSBrowser, setTitleNSBrowser, 2, 0)
 
   NEW_RECEIVER(UIAccessibilityElement)
@@ -225,14 +225,14 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UIAccessibilityElement, setAccessibilityValue, 0)
 
   NEW_RECEIVER(UIAlertAction)
-  IdentifierInfo *actionWithTitleUIAlertAction[] = {
+  const IdentifierInfo *actionWithTitleUIAlertAction[] = {
       &Ctx.Idents.get("actionWithTitle"), &Ctx.Idents.get("style"),
       &Ctx.Idents.get("handler")};
   ADD_METHOD(UIAlertAction, actionWithTitleUIAlertAction, 3, 0)
 
   NEW_RECEIVER(NSPopUpButton)
   ADD_UNARY_METHOD(NSPopUpButton, addItemWithTitle, 0)
-  IdentifierInfo *insertItemWithTitleNSPopUpButton[] = {
+  const IdentifierInfo *insertItemWithTitleNSPopUpButton[] = {
       &Ctx.Idents.get("insertItemWithTitle"), &Ctx.Idents.get("atIndex")};
   ADD_METHOD(NSPopUpButton, insertItemWithTitleNSPopUpButton, 2, 0)
   ADD_UNARY_METHOD(NSPopUpButton, removeItemWithTitle, 0)
@@ -240,7 +240,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSPopUpButton, setTitle, 0)
 
   NEW_RECEIVER(NSTableViewRowAction)
-  IdentifierInfo *rowActionWithStyleNSTableViewRowAction[] = {
+  const IdentifierInfo *rowActionWithStyleNSTableViewRowAction[] = {
       &Ctx.Idents.get("rowActionWithStyle"), &Ctx.Idents.get("title"),
       &Ctx.Idents.get("handler")};
   ADD_METHOD(NSTableViewRowAction, rowActionWithStyleNSTableViewRowAction, 3, 1)
@@ -273,10 +273,10 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSTableColumn, setHeaderToolTip, 0)
 
   NEW_RECEIVER(NSSegmentedControl)
-  IdentifierInfo *setLabelNSSegmentedControl[] = {
+  const IdentifierInfo *setLabelNSSegmentedControl[] = {
       &Ctx.Idents.get("setLabel"), &Ctx.Idents.get("forSegment")};
   ADD_METHOD(NSSegmentedControl, setLabelNSSegmentedControl, 2, 0)
-  IdentifierInfo *setToolTipNSSegmentedControl[] = {
+  const IdentifierInfo *setToolTipNSSegmentedControl[] = {
       &Ctx.Idents.get("setToolTip"), &Ctx.Idents.get("forSegment")};
   ADD_METHOD(NSSegmentedControl, setToolTipNSSegmentedControl, 2, 0)
 
@@ -301,8 +301,8 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSAccessibility, setAccessibilityHelp, 0)
 
   NEW_RECEIVER(NSMatrix)
-  IdentifierInfo *setToolTipNSMatrix[] = {&Ctx.Idents.get("setToolTip"),
-                                          &Ctx.Idents.get("forCell")};
+  const IdentifierInfo *setToolTipNSMatrix[] = {&Ctx.Idents.get("setToolTip"),
+                                                &Ctx.Idents.get("forCell")};
   ADD_METHOD(NSMatrix, setToolTipNSMatrix, 2, 0)
 
   NEW_RECEIVER(NSPrintPanel)
@@ -317,13 +317,13 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSSlider, setTitle, 0)
 
   NEW_RECEIVER(UIMenuItem)
-  IdentifierInfo *initWithTitleUIMenuItem[] = {&Ctx.Idents.get("initWithTitle"),
-                                               &Ctx.Idents.get("action")};
+  const IdentifierInfo *initWithTitleUIMenuItem[] = {
+      &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("action")};
   ADD_METHOD(UIMenuItem, initWithTitleUIMenuItem, 2, 0)
   ADD_UNARY_METHOD(UIMenuItem, setTitle, 0)
 
   NEW_RECEIVER(UIAlertController)
-  IdentifierInfo *alertControllerWithTitleUIAlertController[] = {
+  const IdentifierInfo *alertControllerWithTitleUIAlertController[] = {
       &Ctx.Idents.get("alertControllerWithTitle"), &Ctx.Idents.get("message"),
       &Ctx.Idents.get("preferredStyle")};
   ADD_METHOD(UIAlertController, alertControllerWithTitleUIAlertController, 3, 1)
@@ -331,19 +331,19 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UIAlertController, setMessage, 0)
 
   NEW_RECEIVER(UIApplicationShortcutItem)
-  IdentifierInfo *initWithTypeUIApplicationShortcutItemIcon[] = {
+  const IdentifierInfo *initWithTypeUIApplicationShortcutItemIcon[] = {
       &Ctx.Idents.get("initWithType"), &Ctx.Idents.get("localizedTitle"),
       &Ctx.Idents.get("localizedSubtitle"), &Ctx.Idents.get("icon"),
       &Ctx.Idents.get("userInfo")};
   ADD_METHOD(UIApplicationShortcutItem,
              initWithTypeUIApplicationShortcutItemIcon, 5, 1)
-  IdentifierInfo *initWithTypeUIApplicationShortcutItem[] = {
+  const IdentifierInfo *initWithTypeUIApplicationShortcutItem[] = {
       &Ctx.Idents.get("initWithType"), &Ctx.Idents.get("localizedTitle")};
   ADD_METHOD(UIApplicationShortcutItem, initWithTypeUIApplicationShortcutItem,
              2, 1)
 
   NEW_RECEIVER(UIActionSheet)
-  IdentifierInfo *initWithTitleUIActionSheet[] = {
+  const IdentifierInfo *initWithTitleUIActionSheet[] = {
       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("delegate"),
       &Ctx.Idents.get("cancelButtonTitle"),
       &Ctx.Idents.get("destructiveButtonTitle"),
@@ -353,7 +353,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UIActionSheet, setTitle, 0)
 
   NEW_RECEIVER(UIAccessibilityCustomAction)
-  IdentifierInfo *initWithNameUIAccessibilityCustomAction[] = {
+  const IdentifierInfo *initWithNameUIAccessibilityCustomAction[] = {
       &Ctx.Idents.get("initWithName"), &Ctx.Idents.get("target"),
       &Ctx.Idents.get("selector")};
   ADD_METHOD(UIAccessibilityCustomAction,
@@ -382,7 +382,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
 
   NEW_RECEIVER(NSAttributedString)
   ADD_UNARY_METHOD(NSAttributedString, initWithString, 0)
-  IdentifierInfo *initWithStringNSAttributedString[] = {
+  const IdentifierInfo *initWithStringNSAttributedString[] = {
       &Ctx.Idents.get("initWithString"), &Ctx.Idents.get("attributes")};
   ADD_METHOD(NSAttributedString, initWithStringNSAttributedString, 2, 0)
 
@@ -390,7 +390,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSText, setString, 0)
 
   NEW_RECEIVER(UIKeyCommand)
-  IdentifierInfo *keyCommandWithInputUIKeyCommand[] = {
+  const IdentifierInfo *keyCommandWithInputUIKeyCommand[] = {
       &Ctx.Idents.get("keyCommandWithInput"), &Ctx.Idents.get("modifierFlags"),
       &Ctx.Idents.get("action"), &Ctx.Idents.get("discoverabilityTitle")};
   ADD_METHOD(UIKeyCommand, keyCommandWithInputUIKeyCommand, 4, 3)
@@ -400,7 +400,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UILabel, setText, 0)
 
   NEW_RECEIVER(NSAlert)
-  IdentifierInfo *alertWithMessageTextNSAlert[] = {
+  const IdentifierInfo *alertWithMessageTextNSAlert[] = {
       &Ctx.Idents.get("alertWithMessageText"), &Ctx.Idents.get("defaultButton"),
       &Ctx.Idents.get("alternateButton"), &Ctx.Idents.get("otherButton"),
       &Ctx.Idents.get("informativeTextWithFormat")};
@@ -415,13 +415,13 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UIMutableApplicationShortcutItem, setLocalizedSubtitle, 0)
 
   NEW_RECEIVER(UIButton)
-  IdentifierInfo *setTitleUIButton[] = {&Ctx.Idents.get("setTitle"),
-                                        &Ctx.Idents.get("forState")};
+  const IdentifierInfo *setTitleUIButton[] = {&Ctx.Idents.get("setTitle"),
+                                              &Ctx.Idents.get("forState")};
   ADD_METHOD(UIButton, setTitleUIButton, 2, 0)
 
   NEW_RECEIVER(NSWindow)
   ADD_UNARY_METHOD(NSWindow, setTitle, 0)
-  IdentifierInfo *minFrameWidthWithTitleNSWindow[] = {
+  const IdentifierInfo *minFrameWidthWithTitleNSWindow[] = {
       &Ctx.Idents.get("minFrameWidthWithTitle"), &Ctx.Idents.get("styleMask")};
   ADD_METHOD(NSWindow, minFrameWidthWithTitleNSWindow, 2, 0)
   ADD_UNARY_METHOD(NSWindow, setMiniwindowTitle, 0)
@@ -430,7 +430,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSPathCell, setPlaceholderString, 0)
 
   NEW_RECEIVER(UIDocumentMenuViewController)
-  IdentifierInfo *addOptionWithTitleUIDocumentMenuViewController[] = {
+  const IdentifierInfo *addOptionWithTitleUIDocumentMenuViewController[] = {
       &Ctx.Idents.get("addOptionWithTitle"), &Ctx.Idents.get("image"),
       &Ctx.Idents.get("order"), &Ctx.Idents.get("handler")};
   ADD_METHOD(UIDocumentMenuViewController,
@@ -442,7 +442,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UINavigationItem, setPrompt, 0)
 
   NEW_RECEIVER(UIAlertView)
-  IdentifierInfo *initWithTitleUIAlertView[] = {
+  const IdentifierInfo *initWithTitleUIAlertView[] = {
       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("message"),
       &Ctx.Idents.get("delegate"), &Ctx.Idents.get("cancelButtonTitle"),
       &Ctx.Idents.get("otherButtonTitles")};
@@ -474,11 +474,11 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSProgress, setLocalizedAdditionalDescription, 0)
 
   NEW_RECEIVER(NSSegmentedCell)
-  IdentifierInfo *setLabelNSSegmentedCell[] = {&Ctx.Idents.get("setLabel"),
-                                               &Ctx.Idents.get("forSegment")};
+  const IdentifierInfo *setLabelNSSegmentedCell[] = {
+      &Ctx.Idents.get("setLabel"), &Ctx.Idents.get("forSegment")};
   ADD_METHOD(NSSegmentedCell, setLabelNSSegmentedCell, 2, 0)
-  IdentifierInfo *setToolTipNSSegmentedCell[] = {&Ctx.Idents.get("setToolTip"),
-                                                 &Ctx.Idents.get("forSegment")};
+  const IdentifierInfo *setToolTipNSSegmentedCell[] = {
+      &Ctx.Idents.get("setToolTip"), &Ctx.Idents.get("forSegment")};
   ADD_METHOD(NSSegmentedCell, setToolTipNSSegmentedCell, 2, 0)
 
   NEW_RECEIVER(NSUndoManager)
@@ -487,7 +487,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSUndoManager, redoMenuTitleForUndoActionName, 0)
 
   NEW_RECEIVER(NSMenuItem)
-  IdentifierInfo *initWithTitleNSMenuItem[] = {
+  const IdentifierInfo *initWithTitleNSMenuItem[] = {
       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("action"),
       &Ctx.Idents.get("keyEquivalent")};
   ADD_METHOD(NSMenuItem, initWithTitleNSMenuItem, 3, 0)
@@ -495,11 +495,11 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSMenuItem, setToolTip, 0)
 
   NEW_RECEIVER(NSPopUpButtonCell)
-  IdentifierInfo *initTextCellNSPopUpButtonCell[] = {
+  const IdentifierInfo *initTextCellNSPopUpButtonCell[] = {
       &Ctx.Idents.get("initTextCell"), &Ctx.Idents.get("pullsDown")};
   ADD_METHOD(NSPopUpButtonCell, initTextCellNSPopUpButtonCell, 2, 0)
   ADD_UNARY_METHOD(NSPopUpButtonCell, addItemWithTitle, 0)
-  IdentifierInfo *insertItemWithTitleNSPopUpButtonCell[] = {
+  const IdentifierInfo *insertItemWithTitleNSPopUpButtonCell[] = {
       &Ctx.Idents.get("insertItemWithTitle"), &Ctx.Idents.get("atIndex")};
   ADD_METHOD(NSPopUpButtonCell, insertItemWithTitleNSPopUpButtonCell, 2, 0)
   ADD_UNARY_METHOD(NSPopUpButtonCell, removeItemWithTitle, 0)
@@ -511,11 +511,11 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
 
   NEW_RECEIVER(NSMenu)
   ADD_UNARY_METHOD(NSMenu, initWithTitle, 0)
-  IdentifierInfo *insertItemWithTitleNSMenu[] = {
+  const IdentifierInfo *insertItemWithTitleNSMenu[] = {
       &Ctx.Idents.get("insertItemWithTitle"), &Ctx.Idents.get("action"),
       &Ctx.Idents.get("keyEquivalent"), &Ctx.Idents.get("atIndex")};
   ADD_METHOD(NSMenu, insertItemWithTitleNSMenu, 4, 0)
-  IdentifierInfo *addItemWithTitleNSMenu[] = {
+  const IdentifierInfo *addItemWithTitleNSMenu[] = {
       &Ctx.Idents.get("addItemWithTitle"), &Ctx.Idents.get("action"),
       &Ctx.Idents.get("keyEquivalent")};
   ADD_METHOD(NSMenu, addItemWithTitleNSMenu, 3, 0)
@@ -526,15 +526,15 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
 
   NEW_RECEIVER(NSForm)
   ADD_UNARY_METHOD(NSForm, addEntry, 0)
-  IdentifierInfo *insertEntryNSForm[] = {&Ctx.Idents.get("insertEntry"),
-                                         &Ctx.Idents.get("atIndex")};
+  const IdentifierInfo *insertEntryNSForm[] = {&Ctx.Idents.get("insertEntry"),
+                                               &Ctx.Idents.get("atIndex")};
   ADD_METHOD(NSForm, insertEntryNSForm, 2, 0)
 
   NEW_RECEIVER(NSTextFieldCell)
   ADD_UNARY_METHOD(NSTextFieldCell, setPlaceholderString, 0)
 
   NEW_RECEIVER(NSUserNotificationAction)
-  IdentifierInfo *actionWithIdentifierNSUserNotificationAction[] = {
+  const IdentifierInfo *actionWithIdentifierNSUserNotificationAction[] = {
       &Ctx.Idents.get("actionWithIdentifier"), &Ctx.Idents.get("title")};
   ADD_METHOD(NSUserNotificationAction,
              actionWithIdentifierNSUserNotificationAction, 2, 1)
@@ -544,7 +544,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UITextField, setPlaceholder, 0)
 
   NEW_RECEIVER(UIBarButtonItem)
-  IdentifierInfo *initWithTitleUIBarButtonItem[] = {
+  const IdentifierInfo *initWithTitleUIBarButtonItem[] = {
       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("style"),
       &Ctx.Idents.get("target"), &Ctx.Idents.get("action")};
   ADD_METHOD(UIBarButtonItem, initWithTitleUIBarButtonItem, 4, 0)
@@ -553,16 +553,16 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UIViewController, setTitle, 0)
 
   NEW_RECEIVER(UISegmentedControl)
-  IdentifierInfo *insertSegmentWithTitleUISegmentedControl[] = {
+  const IdentifierInfo *insertSegmentWithTitleUISegmentedControl[] = {
       &Ctx.Idents.get("insertSegmentWithTitle"), &Ctx.Idents.get("atIndex"),
       &Ctx.Idents.get("animated")};
   ADD_METHOD(UISegmentedControl, insertSegmentWithTitleUISegmentedControl, 3, 0)
-  IdentifierInfo *setTitleUISegmentedControl[] = {
+  const IdentifierInfo *setTitleUISegmentedControl[] = {
       &Ctx.Idents.get("setTitle"), &Ctx.Idents.get("forSegmentAtIndex")};
   ADD_METHOD(UISegmentedControl, setTitleUISegmentedControl, 2, 0)
 
   NEW_RECEIVER(NSAccessibilityCustomRotorItemResult)
-  IdentifierInfo
+  const IdentifierInfo
       *initWithItemLoadingTokenNSAccessibilityCustomRotorItemResult[] = {
           &Ctx.Idents.get("initWithItemLoadingToken"),
           &Ctx.Idents.get("customLabel")};
@@ -571,7 +571,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSAccessibilityCustomRotorItemResult, setCustomLabel, 0)
 
   NEW_RECEIVER(UIContextualAction)
-  IdentifierInfo *contextualActionWithStyleUIContextualAction[] = {
+  const IdentifierInfo *contextualActionWithStyleUIContextualAction[] = {
       &Ctx.Idents.get("contextualActionWithStyle"), &Ctx.Idents.get("title"),
       &Ctx.Idents.get("handler")};
   ADD_METHOD(UIContextualAction, contextualActionWithStyleUIContextualAction, 3,
@@ -579,7 +579,7 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(UIContextualAction, setTitle, 0)
 
   NEW_RECEIVER(NSAccessibilityCustomRotor)
-  IdentifierInfo *initWithLabelNSAccessibilityCustomRotor[] = {
+  const IdentifierInfo *initWithLabelNSAccessibilityCustomRotor[] = {
       &Ctx.Idents.get("initWithLabel"), &Ctx.Idents.get("itemSearchDelegate")};
   ADD_METHOD(NSAccessibilityCustomRotor,
              initWithLabelNSAccessibilityCustomRotor, 2, 0)
@@ -590,11 +590,11 @@ void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
   ADD_UNARY_METHOD(NSWindowTab, setToolTip, 0)
 
   NEW_RECEIVER(NSAccessibilityCustomAction)
-  IdentifierInfo *initWithNameNSAccessibilityCustomAction[] = {
+  const IdentifierInfo *initWithNameNSAccessibilityCustomAction[] = {
       &Ctx.Idents.get("initWithName"), &Ctx.Idents.get("handler")};
   ADD_METHOD(NSAccessibilityCustomAction,
              initWithNameNSAccessibilityCustomAction, 2, 0)
-  IdentifierInfo *initWithNameTargetNSAccessibilityCustomAction[] = {
+  const IdentifierInfo *initWithNameTargetNSAccessibilityCustomAction[] = {
       &Ctx.Idents.get("initWithName"), &Ctx.Idents.get("target"),
       &Ctx.Idents.get("selector")};
   ADD_METHOD(NSAccessibilityCustomAction,
@@ -618,12 +618,12 @@ void NonLocalizedStringChecker::initLocStringsMethods(ASTContext &Ctx) const {
   if (!LSM.empty())
     return;
 
-  IdentifierInfo *LocalizedStringMacro[] = {
+  const IdentifierInfo *LocalizedStringMacro[] = {
       &Ctx.Idents.get("localizedStringForKey"), &Ctx.Idents.get("value"),
       &Ctx.Idents.get("table")};
   LSM_INSERT_SELECTOR("NSBundle", LocalizedStringMacro, 3)
   LSM_INSERT_UNARY("NSDateFormatter", "stringFromDate")
-  IdentifierInfo *LocalizedStringFromDate[] = {
+  const IdentifierInfo *LocalizedStringFromDate[] = {
       &Ctx.Idents.get("localizedStringFromDate"), &Ctx.Idents.get("dateStyle"),
       &Ctx.Idents.get("timeStyle")};
   LSM_INSERT_SELECTOR("NSDateFormatter", LocalizedStringFromDate, 3)
@@ -903,7 +903,7 @@ static inline bool isNSStringType(QualType T, ASTContext &Ctx) {
   if (!Cls)
     return false;
 
-  IdentifierInfo *ClsName = Cls->getIdentifier();
+  const IdentifierInfo *ClsName = Cls->getIdentifier();
 
   // FIXME: Should we walk the chain of classes?
   return ClsName == &Ctx.Idents.get("NSString") ||

diff  --git a/clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp
index 06f1ad00eaf20d..60934e51febe84 100644
--- a/clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp
@@ -1082,7 +1082,8 @@ void NullabilityChecker::checkPostObjCMessage(const ObjCMethodCall &M,
       M.getMessageKind() == OCM_PropertyAccess && !C.wasInlined) {
     bool LookupResolved = false;
     if (const MemRegion *ReceiverRegion = getTrackRegion(M.getReceiverSVal())) {
-      if (IdentifierInfo *Ident = M.getSelector().getIdentifierInfoForSlot(0)) {
+      if (const IdentifierInfo *Ident =
+              M.getSelector().getIdentifierInfoForSlot(0)) {
         LookupResolved = true;
         ObjectPropPair Key = std::make_pair(ReceiverRegion, Ident);
         const ConstrainedPropertyVal *PrevPropVal =

diff  --git a/clang/lib/StaticAnalyzer/Checkers/ObjCMissingSuperCallChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/ObjCMissingSuperCallChecker.cpp
index 598b368e74d47a..03dab4f7ada7ae 100644
--- a/clang/lib/StaticAnalyzer/Checkers/ObjCMissingSuperCallChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/ObjCMissingSuperCallChecker.cpp
@@ -107,7 +107,7 @@ void ObjCSuperCallChecker::fillSelectors(ASTContext &Ctx,
     assert(Descriptor.ArgumentCount <= 1); // No multi-argument selectors yet.
 
     // Get the selector.
-    IdentifierInfo *II = &Ctx.Idents.get(Descriptor.SelectorName);
+    const IdentifierInfo *II = &Ctx.Idents.get(Descriptor.SelectorName);
 
     Selector Sel = Ctx.Selectors.getSelector(Descriptor.ArgumentCount, &II);
     ClassSelectors.insert(Sel);

diff  --git a/clang/lib/StaticAnalyzer/Checkers/ObjCSuperDeallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/ObjCSuperDeallocChecker.cpp
index eb40711812e16b..a6c4186cb15bba 100644
--- a/clang/lib/StaticAnalyzer/Checkers/ObjCSuperDeallocChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/ObjCSuperDeallocChecker.cpp
@@ -26,8 +26,8 @@ namespace {
 class ObjCSuperDeallocChecker
     : public Checker<check::PostObjCMessage, check::PreObjCMessage,
                      check::PreCall, check::Location> {
-  mutable IdentifierInfo *IIdealloc = nullptr;
-  mutable IdentifierInfo *IINSObject = nullptr;
+  mutable const IdentifierInfo *IIdealloc = nullptr;
+  mutable const IdentifierInfo *IINSObject = nullptr;
   mutable Selector SELdealloc;
 
   const BugType DoubleSuperDeallocBugType{

diff  --git a/clang/tools/libclang/CIndexCodeCompletion.cpp b/clang/tools/libclang/CIndexCodeCompletion.cpp
index 3c5f390f6d888a..850c004680fd96 100644
--- a/clang/tools/libclang/CIndexCodeCompletion.cpp
+++ b/clang/tools/libclang/CIndexCodeCompletion.cpp
@@ -601,15 +601,15 @@ namespace {
       AllocatedResults.Contexts = getContextsForContextKind(contextKind, S);
       
       AllocatedResults.Selector = "";
-      ArrayRef<IdentifierInfo *> SelIdents = Context.getSelIdents();
-      for (ArrayRef<IdentifierInfo *>::iterator I = SelIdents.begin(),
-                                                E = SelIdents.end();
+      ArrayRef<const IdentifierInfo *> SelIdents = Context.getSelIdents();
+      for (ArrayRef<const IdentifierInfo *>::iterator I = SelIdents.begin(),
+                                                      E = SelIdents.end();
            I != E; ++I) {
-        if (IdentifierInfo *selIdent = *I)
+        if (const IdentifierInfo *selIdent = *I)
           AllocatedResults.Selector += selIdent->getName();
         AllocatedResults.Selector += ":";
       }
-      
+
       QualType baseType = Context.getBaseType();
       NamedDecl *D = nullptr;
 

diff  --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTUtils.h b/lldb/source/Plugins/ExpressionParser/Clang/ASTUtils.h
index 95e8a600f83824..cefec15a79809d 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTUtils.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ASTUtils.h
@@ -56,7 +56,7 @@ class ExternalASTSourceWrapper : public clang::ExternalSemaSource {
     return m_Source->GetExternalCXXBaseSpecifiers(Offset);
   }
 
-  void updateOutOfDateIdentifier(clang::IdentifierInfo &II) override {
+  void updateOutOfDateIdentifier(const clang::IdentifierInfo &II) override {
     m_Source->updateOutOfDateIdentifier(II);
   }
 

diff  --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
index a95a9e9f01e3fc..75493eb10d7311 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
@@ -713,17 +713,18 @@ bool ClangASTSource::FindObjCMethodDeclsWithOrigin(
   Selector original_selector;
 
   if (decl_name.isObjCZeroArgSelector()) {
-    IdentifierInfo *ident = &original_ctx->Idents.get(decl_name.getAsString());
+    const IdentifierInfo *ident =
+        &original_ctx->Idents.get(decl_name.getAsString());
     original_selector = original_ctx->Selectors.getSelector(0, &ident);
   } else if (decl_name.isObjCOneArgSelector()) {
     const std::string &decl_name_string = decl_name.getAsString();
     std::string decl_name_string_without_colon(decl_name_string.c_str(),
                                                decl_name_string.length() - 1);
-    IdentifierInfo *ident =
+    const IdentifierInfo *ident =
         &original_ctx->Idents.get(decl_name_string_without_colon);
     original_selector = original_ctx->Selectors.getSelector(1, &ident);
   } else {
-    SmallVector<IdentifierInfo *, 4> idents;
+    SmallVector<const IdentifierInfo *, 4> idents;
 
     clang::Selector sel = decl_name.getObjCSelector();
 

diff  --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
index 5d7c5f38d18051..6894cdccaf95a7 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
@@ -316,7 +316,7 @@ class ObjCRuntimeMethodType {
     const bool HasRelatedResultType = false;
     const bool for_expression = true;
 
-    std::vector<clang::IdentifierInfo *> selector_components;
+    std::vector<const clang::IdentifierInfo *> selector_components;
 
     const char *name_cursor = name;
     bool is_zero_argument = true;
@@ -335,7 +335,7 @@ class ObjCRuntimeMethodType {
       }
     }
 
-    clang::IdentifierInfo **identifier_infos = selector_components.data();
+    const clang::IdentifierInfo **identifier_infos = selector_components.data();
     if (!identifier_infos) {
       return nullptr;
     }

diff  --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 4a1c8d57655215..ee634d12b3c41e 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -7910,14 +7910,14 @@ bool TypeSystemClang::AddObjCClassProperty(
   if (property_setter_name) {
     std::string property_setter_no_colon(property_setter_name,
                                          strlen(property_setter_name) - 1);
-    clang::IdentifierInfo *setter_ident =
+    const clang::IdentifierInfo *setter_ident =
         &clang_ast.Idents.get(property_setter_no_colon);
     setter_sel = clang_ast.Selectors.getSelector(1, &setter_ident);
   } else if (!(property_attributes & DW_APPLE_PROPERTY_readonly)) {
     std::string setter_sel_string("set");
     setter_sel_string.push_back(::toupper(property_name[0]));
     setter_sel_string.append(&property_name[1]);
-    clang::IdentifierInfo *setter_ident =
+    const clang::IdentifierInfo *setter_ident =
         &clang_ast.Idents.get(setter_sel_string);
     setter_sel = clang_ast.Selectors.getSelector(1, &setter_ident);
   }
@@ -7925,11 +7925,12 @@ bool TypeSystemClang::AddObjCClassProperty(
   property_decl->setPropertyAttributes(ObjCPropertyAttribute::kind_setter);
 
   if (property_getter_name != nullptr) {
-    clang::IdentifierInfo *getter_ident =
+    const clang::IdentifierInfo *getter_ident =
         &clang_ast.Idents.get(property_getter_name);
     getter_sel = clang_ast.Selectors.getSelector(0, &getter_ident);
   } else {
-    clang::IdentifierInfo *getter_ident = &clang_ast.Idents.get(property_name);
+    const clang::IdentifierInfo *getter_ident =
+        &clang_ast.Idents.get(property_name);
     getter_sel = clang_ast.Selectors.getSelector(0, &getter_ident);
   }
   property_decl->setGetterName(getter_sel);
@@ -8091,7 +8092,7 @@ clang::ObjCMethodDecl *TypeSystemClang::AddMethodToObjCObjectType(
     return nullptr;
 
   selector_start++;
-  llvm::SmallVector<clang::IdentifierInfo *, 12> selector_idents;
+  llvm::SmallVector<const clang::IdentifierInfo *, 12> selector_idents;
 
   size_t len = 0;
   const char *start;


        


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