Vendor import of clang trunk r178860:

http://llvm.org/svn/llvm-project/cfe/trunk@178860

1 files changed, 149 insertions, 178 deletions

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 087a585..7927279 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -16,33 +16,34 @@
 
 #include "clang/AST/APValue.h"
 #include "clang/AST/DeclBase.h"
-#include "clang/AST/Redeclarable.h"
 #include "clang/AST/DeclarationName.h"
 #include "clang/AST/ExternalASTSource.h"
+#include "clang/AST/Redeclarable.h"
+#include "clang/AST/Type.h"
 #include "clang/Basic/Linkage.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/Support/Compiler.h"
 
 namespace clang {
+struct ASTTemplateArgumentListInfo;
 class CXXTemporary;
+class CompoundStmt;
+class DependentFunctionTemplateSpecializationInfo;
 class Expr;
 class FunctionTemplateDecl;
+class FunctionTemplateSpecializationInfo;
+class LabelStmt;
+class MemberSpecializationInfo;
+class Module;
+class NestedNameSpecifier;
 class Stmt;
-class CompoundStmt;
 class StringLiteral;
-class NestedNameSpecifier;
-class TemplateParameterList;
 class TemplateArgumentList;
-struct ASTTemplateArgumentListInfo;
-class MemberSpecializationInfo;
-class FunctionTemplateSpecializationInfo;
-class DependentFunctionTemplateSpecializationInfo;
+class TemplateParameterList;
 class TypeLoc;
 class UnresolvedSetImpl;
-class LabelStmt;
-class Module;
-  
+
 /// \brief A container of type source information.
 ///
 /// A client can read the relevant info using TypeLoc wrappers, e.g:
@@ -108,6 +109,7 @@ class NamedDecl : public Decl {
 
 private:
   NamedDecl *getUnderlyingDeclImpl();
+  void verifyLinkage() const;
 
 protected:
   NamedDecl(Kind DK, DeclContext *DC, SourceLocation L, DeclarationName N)
@@ -149,32 +151,29 @@ public:
   /// \brief Set the name of this declaration.
   void setDeclName(DeclarationName N) { Name = N; }
 
-  /// getQualifiedNameAsString - Returns human-readable qualified name for
+  /// printQualifiedName - Returns human-readable qualified name for
   /// declaration, like A::B::i, for i being member of namespace A::B.
   /// If declaration is not member of context which can be named (record,
-  /// namespace), it will return same result as getNameAsString().
+  /// namespace), it will return same result as printName().
   /// Creating this name is expensive, so it should be called only when
   /// performance doesn't matter.
+  void printQualifiedName(raw_ostream &OS) const;
+  void printQualifiedName(raw_ostream &OS, const PrintingPolicy &Policy) const;
+
+  // FIXME: Remove string versions.
   std::string getQualifiedNameAsString() const;
   std::string getQualifiedNameAsString(const PrintingPolicy &Policy) const;
 
   /// getNameForDiagnostic - Appends a human-readable name for this
-  /// declaration into the given string.
+  /// declaration into the given stream.
   ///
   /// This is the method invoked by Sema when displaying a NamedDecl
   /// in a diagnostic.  It does not necessarily produce the same
-  /// result as getNameAsString(); for example, class template
+  /// result as printName(); for example, class template
   /// specializations are printed with their template arguments.
-  ///
-  /// TODO: use an API that doesn't require so many temporary strings
-  virtual void getNameForDiagnostic(std::string &S,
+  virtual void getNameForDiagnostic(raw_ostream &OS,
                                     const PrintingPolicy &Policy,
-                                    bool Qualified) const {
-    if (Qualified)
-      S += getQualifiedNameAsString(Policy);
-    else
-      S += getNameAsString();
-  }
+                                    bool Qualified) const;
 
   /// declarationReplaces - Determine whether this declaration, if
   /// known to be well-formed within its context, will replace the
@@ -212,117 +211,40 @@ public:
   /// a C++ class.
   bool isCXXInstanceMember() const;
 
-  class LinkageInfo {
-    uint8_t linkage_    : 2;
-    uint8_t visibility_ : 2;
-    uint8_t explicit_   : 1;
-
-    void setVisibility(Visibility V, bool E) { visibility_ = V; explicit_ = E; }
-  public:
-    LinkageInfo() : linkage_(ExternalLinkage), visibility_(DefaultVisibility),
-                    explicit_(false) {}
-    LinkageInfo(Linkage L, Visibility V, bool E)
-      : linkage_(L), visibility_(V), explicit_(E) {
-      assert(linkage() == L && visibility() == V && visibilityExplicit() == E &&
-             "Enum truncated!");
-    }
-
-    static LinkageInfo external() {
-      return LinkageInfo();
-    }
-    static LinkageInfo internal() {
-      return LinkageInfo(InternalLinkage, DefaultVisibility, false);
-    }
-    static LinkageInfo uniqueExternal() {
-      return LinkageInfo(UniqueExternalLinkage, DefaultVisibility, false);
-    }
-    static LinkageInfo none() {
-      return LinkageInfo(NoLinkage, DefaultVisibility, false);
-    }
-
-    Linkage linkage() const { return (Linkage)linkage_; }
-    Visibility visibility() const { return (Visibility)visibility_; }
-    bool visibilityExplicit() const { return explicit_; }
-
-    void setLinkage(Linkage L) { linkage_ = L; }
-    void mergeLinkage(Linkage L) {
-      setLinkage(minLinkage(linkage(), L));
-    }
-    void mergeLinkage(LinkageInfo Other) {
-      mergeLinkage(Other.linkage());
-    }
-
-    // Merge the visibility V giving preference to explicit ones.
-    // This is used, for example, when merging the visibility of a class
-    // down to one of its members. If the member has no explicit visibility,
-    // the class visibility wins.
-    void mergeVisibility(Visibility V, bool E = false) {
-      // Never increase the visibility
-      if (visibility() < V)
-        return;
-
-      // If we have an explicit visibility, keep it
-      if (visibilityExplicit())
-        return;
-
-      setVisibility(V, E);
-    }
-    // Merge the visibility V, keeping the most restrictive one.
-    // This is used for cases like merging the visibility of a template
-    // argument to an instantiation. If we already have a hidden class,
-    // no argument should give it default visibility.
-    void mergeVisibilityWithMin(Visibility V, bool E = false) {
-      // Never increase the visibility
-      if (visibility() < V)
-        return;
-
-      // FIXME: this
-      // If this visibility is explicit, keep it.
-      if (visibilityExplicit() && !E)
-        return;
-
-      // should be replaced with this
-      // Don't lose the explicit bit for nothing
-      //      if (visibility() == V && visibilityExplicit())
-      //        return;
-
-      setVisibility(V, E);
-    }
-    void mergeVisibility(LinkageInfo Other) {
-      mergeVisibility(Other.visibility(), Other.visibilityExplicit());
-    }
-    void mergeVisibilityWithMin(LinkageInfo Other) {
-      mergeVisibilityWithMin(Other.visibility(), Other.visibilityExplicit());
-    }
-
-    void merge(LinkageInfo Other) {
-      mergeLinkage(Other);
-      mergeVisibility(Other);
-    }
-    void mergeWithMin(LinkageInfo Other) {
-      mergeLinkage(Other);
-      mergeVisibilityWithMin(Other);
-    }
-  };
-
   /// \brief Determine what kind of linkage this entity has.
   Linkage getLinkage() const;
 
+  /// \brief True if this decl has external linkage.
+  bool hasExternalLinkage() const {
+    return getLinkage() == ExternalLinkage;
+  }
+
+  /// \brief True if this decl has external linkage. Don't cache the linkage,
+  /// because we are not finished setting up the redecl chain for the decl.
+  bool hasExternalLinkageUncached() const;
+
   /// \brief Determines the visibility of this entity.
   Visibility getVisibility() const {
-    return getLinkageAndVisibility().visibility();
+    return getLinkageAndVisibility().getVisibility();
   }
 
   /// \brief Determines the linkage and visibility of this entity.
   LinkageInfo getLinkageAndVisibility() const;
 
+  /// Kinds of explicit visibility.
+  enum ExplicitVisibilityKind {
+    VisibilityForType,
+    VisibilityForValue
+  };
+
   /// \brief If visibility was explicitly specified for this
   /// declaration, return that visibility.
-  llvm::Optional<Visibility> getExplicitVisibility() const;
+  Optional<Visibility>
+  getExplicitVisibility(ExplicitVisibilityKind kind) const;
 
-  /// \brief Clear the linkage cache in response to a change
-  /// to the declaration.
-  void ClearLinkageCache();
+  /// \brief True if the computed linkage is valid. Used for consistency
+  /// checking. Should always return true.
+  bool isLinkageValid() const;
 
   /// \brief Looks through UsingDecls and ObjCCompatibleAliasDecls for
   /// the underlying named decl.
@@ -538,9 +460,7 @@ public:
 
   /// \brief Determine whether this symbol is weakly-imported,
   ///        or declared with the weak or weak-ref attr.
-  bool isWeak() const {
-    return hasAttr<WeakAttr>() || hasAttr<WeakRefAttr>() || isWeakImported();
-  }
+  bool isWeak() const;
 
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
@@ -744,7 +664,6 @@ private:
     friend class ASTDeclReader;
 
     unsigned SClass : 3;
-    unsigned SClassAsWritten : 3;
     unsigned ThreadSpecified : 1;
     unsigned InitStyle : 2;
 
@@ -811,14 +730,12 @@ protected:
 
   VarDecl(Kind DK, DeclContext *DC, SourceLocation StartLoc,
           SourceLocation IdLoc, IdentifierInfo *Id,
-          QualType T, TypeSourceInfo *TInfo, StorageClass SC,
-          StorageClass SCAsWritten)
+          QualType T, TypeSourceInfo *TInfo, StorageClass SC)
     : DeclaratorDecl(DK, DC, IdLoc, Id, T, TInfo, StartLoc), Init() {
     assert(sizeof(VarDeclBitfields) <= sizeof(unsigned));
     assert(sizeof(ParmVarDeclBitfields) <= sizeof(unsigned));
     AllBits = 0;
     VarDeclBits.SClass = SC;
-    VarDeclBits.SClassAsWritten = SCAsWritten;
     // Everything else is implicitly initialized to false.
   }
 
@@ -841,23 +758,18 @@ public:
   static VarDecl *Create(ASTContext &C, DeclContext *DC,
                          SourceLocation StartLoc, SourceLocation IdLoc,
                          IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
-                         StorageClass S, StorageClass SCAsWritten);
+                         StorageClass S);
 
   static VarDecl *CreateDeserialized(ASTContext &C, unsigned ID);
   
   virtual SourceRange getSourceRange() const LLVM_READONLY;
 
+  /// \brief Returns the storage class as written in the source. For the
+  /// computed linkage of symbol, see getLinkage.
   StorageClass getStorageClass() const {
     return (StorageClass) VarDeclBits.SClass;
   }
-  StorageClass getStorageClassAsWritten() const {
-    return (StorageClass) VarDeclBits.SClassAsWritten;
-  }
   void setStorageClass(StorageClass SC);
-  void setStorageClassAsWritten(StorageClass SC) {
-    assert(isLegalForVariable(SC));
-    VarDeclBits.SClassAsWritten = SC;
-  }
 
   void setThreadSpecified(bool T) { VarDeclBits.ThreadSpecified = T; }
   bool isThreadSpecified() const {
@@ -882,8 +794,8 @@ public:
     return getStorageClass() == SC_Static && !isFileVarDecl();
   }
 
-  /// hasExternStorage - Returns true if a variable has extern or
-  /// __private_extern__ storage.
+  /// \brief Returns true if a variable has extern or __private_extern__
+  /// storage.
   bool hasExternalStorage() const {
     return getStorageClass() == SC_Extern ||
            getStorageClass() == SC_PrivateExtern;
@@ -894,6 +806,9 @@ public:
   ///  as static variables declared within a function.
   bool hasGlobalStorage() const { return !hasLocalStorage(); }
 
+  /// Compute the language linkage.
+  LanguageLinkage getLanguageLinkage() const;
+
   /// \brief Determines whether this variable is a variable with
   /// external, C linkage.
   bool isExternC() const;
@@ -1087,8 +1002,7 @@ public:
   /// not a constant expression. Returns a pointer to the value if evaluation
   /// succeeded, 0 otherwise.
   APValue *evaluateValue() const;
-  APValue *evaluateValue(
-    llvm::SmallVectorImpl<PartialDiagnosticAt> &Notes) const;
+  APValue *evaluateValue(SmallVectorImpl<PartialDiagnosticAt> &Notes) const;
 
   /// \brief Return the already-evaluated value of this variable's
   /// initializer, or NULL if the value is not yet known. Returns pointer
@@ -1220,7 +1134,7 @@ public:
   ImplicitParamDecl(DeclContext *DC, SourceLocation IdLoc,
                     IdentifierInfo *Id, QualType Type)
     : VarDecl(ImplicitParam, DC, IdLoc, IdLoc, Id, Type,
-              /*tinfo*/ 0, SC_None, SC_None) {
+              /*tinfo*/ 0, SC_None) {
     setImplicit();
   }
 
@@ -1239,8 +1153,8 @@ protected:
   ParmVarDecl(Kind DK, DeclContext *DC, SourceLocation StartLoc,
               SourceLocation IdLoc, IdentifierInfo *Id,
               QualType T, TypeSourceInfo *TInfo,
-              StorageClass S, StorageClass SCAsWritten, Expr *DefArg)
-    : VarDecl(DK, DC, StartLoc, IdLoc, Id, T, TInfo, S, SCAsWritten) {
+              StorageClass S, Expr *DefArg)
+    : VarDecl(DK, DC, StartLoc, IdLoc, Id, T, TInfo, S) {
     assert(ParmVarDeclBits.HasInheritedDefaultArg == false);
     assert(ParmVarDeclBits.IsKNRPromoted == false);
     assert(ParmVarDeclBits.IsObjCMethodParam == false);
@@ -1252,8 +1166,7 @@ public:
                              SourceLocation StartLoc,
                              SourceLocation IdLoc, IdentifierInfo *Id,
                              QualType T, TypeSourceInfo *TInfo,
-                             StorageClass S, StorageClass SCAsWritten,
-                             Expr *DefArg);
+                             StorageClass S, Expr *DefArg);
 
   static ParmVarDecl *CreateDeserialized(ASTContext &C, unsigned ID);
   
@@ -1451,14 +1364,13 @@ private:
   /// DeclsInPrototypeScope - Array of pointers to NamedDecls for
   /// decls defined in the function prototype that are not parameters. E.g.
   /// 'enum Y' in 'void f(enum Y {AA} x) {}'.
-  llvm::ArrayRef<NamedDecl*> DeclsInPrototypeScope;
+  ArrayRef<NamedDecl *> DeclsInPrototypeScope;
 
   LazyDeclStmtPtr Body;
 
   // FIXME: This can be packed into the bitfields in Decl.
   // NOTE: VC++ treats enums as signed, avoid using the StorageClass enum
   unsigned SClass : 2;
-  unsigned SClassAsWritten : 2;
   bool IsInline : 1;
   bool IsInlineSpecified : 1;
   bool IsVirtualAsWritten : 1;
@@ -1473,6 +1385,10 @@ private:
   bool IsLateTemplateParsed : 1;
   bool IsConstexpr : 1;
 
+  /// \brief Indicates if the function was a definition but its body was
+  /// skipped.
+  unsigned HasSkippedBody : 1;
+
   /// \brief End part of this FunctionDecl's source range.
   ///
   /// We could compute the full range in getSourceRange(). However, when we're
@@ -1538,25 +1454,26 @@ private:
   void setInstantiationOfMemberFunction(ASTContext &C, FunctionDecl *FD,
                                         TemplateSpecializationKind TSK);
 
-  void setParams(ASTContext &C, llvm::ArrayRef<ParmVarDecl *> NewParamInfo);
+  void setParams(ASTContext &C, ArrayRef<ParmVarDecl *> NewParamInfo);
 
 protected:
   FunctionDecl(Kind DK, DeclContext *DC, SourceLocation StartLoc,
                const DeclarationNameInfo &NameInfo,
                QualType T, TypeSourceInfo *TInfo,
-               StorageClass S, StorageClass SCAsWritten, bool isInlineSpecified,
+               StorageClass S, bool isInlineSpecified,
                bool isConstexprSpecified)
     : DeclaratorDecl(DK, DC, NameInfo.getLoc(), NameInfo.getName(), T, TInfo,
                      StartLoc),
       DeclContext(DK),
       ParamInfo(0), Body(),
-      SClass(S), SClassAsWritten(SCAsWritten),
+      SClass(S),
       IsInline(isInlineSpecified), IsInlineSpecified(isInlineSpecified),
       IsVirtualAsWritten(false), IsPure(false), HasInheritedPrototype(false),
       HasWrittenPrototype(true), IsDeleted(false), IsTrivial(false),
       IsDefaulted(false), IsExplicitlyDefaulted(false),
       HasImplicitReturnZero(false), IsLateTemplateParsed(false),
-      IsConstexpr(isConstexprSpecified), EndRangeLoc(NameInfo.getEndLoc()),
+      IsConstexpr(isConstexprSpecified), HasSkippedBody(false),
+      EndRangeLoc(NameInfo.getEndLoc()),
       TemplateOrSpecialization(),
       DNLoc(NameInfo.getInfo()) {}
 
@@ -1580,14 +1497,13 @@ public:
                               SourceLocation StartLoc, SourceLocation NLoc,
                               DeclarationName N, QualType T,
                               TypeSourceInfo *TInfo,
-                              StorageClass SC = SC_None,
-                              StorageClass SCAsWritten = SC_None,
+                              StorageClass SC,
                               bool isInlineSpecified = false,
                               bool hasWrittenPrototype = true,
                               bool isConstexprSpecified = false) {
     DeclarationNameInfo NameInfo(N, NLoc);
     return FunctionDecl::Create(C, DC, StartLoc, NameInfo, T, TInfo,
-                                SC, SCAsWritten,
+                                SC,
                                 isInlineSpecified, hasWrittenPrototype,
                                 isConstexprSpecified);
   }
@@ -1596,10 +1512,9 @@ public:
                               SourceLocation StartLoc,
                               const DeclarationNameInfo &NameInfo,
                               QualType T, TypeSourceInfo *TInfo,
-                              StorageClass SC = SC_None,
-                              StorageClass SCAsWritten = SC_None,
-                              bool isInlineSpecified = false,
-                              bool hasWrittenPrototype = true,
+                              StorageClass SC,
+                              bool isInlineSpecified,
+                              bool hasWrittenPrototype,
                               bool isConstexprSpecified = false);
 
   static FunctionDecl *CreateDeserialized(ASTContext &C, unsigned ID);
@@ -1608,7 +1523,7 @@ public:
     return DeclarationNameInfo(getDeclName(), getLocation(), DNLoc);
   }
 
-  virtual void getNameForDiagnostic(std::string &S,
+  virtual void getNameForDiagnostic(raw_ostream &OS,
                                     const PrintingPolicy &Policy,
                                     bool Qualified) const;
 
@@ -1732,7 +1647,7 @@ public:
 
   /// Whether this is a (C++11) constexpr function or constexpr constructor.
   bool isConstexpr() const { return IsConstexpr; }
-  void setConstexpr(bool IC);
+  void setConstexpr(bool IC) { IsConstexpr = IC; }
 
   /// \brief Whether this function has been deleted.
   ///
@@ -1776,6 +1691,9 @@ public:
   /// This function must be an allocation or deallocation function.
   bool isReservedGlobalPlacementOperator() const;
 
+  /// Compute the language linkage.
+  LanguageLinkage getLanguageLinkage() const;
+
   /// \brief Determines whether this function is a function with
   /// external, C linkage.
   bool isExternC() const;
@@ -1783,6 +1701,14 @@ public:
   /// \brief Determines whether this is a global function.
   bool isGlobal() const;
 
+  /// \brief Determines whether this function is known to be 'noreturn', through
+  /// an attribute on its declaration or its type.
+  bool isNoReturn() const;
+
+  /// \brief True if the function was a definition but its body was skipped.
+  bool hasSkippedBody() const { return HasSkippedBody; }
+  void setHasSkippedBody(bool Skipped = true) { HasSkippedBody = Skipped; }
+
   void setPreviousDeclaration(FunctionDecl * PrevDecl);
 
   virtual const FunctionDecl *getCanonicalDecl() const;
@@ -1814,14 +1740,14 @@ public:
     assert(i < getNumParams() && "Illegal param #");
     return ParamInfo[i];
   }
-  void setParams(llvm::ArrayRef<ParmVarDecl *> NewParamInfo) {
+  void setParams(ArrayRef<ParmVarDecl *> NewParamInfo) {
     setParams(getASTContext(), NewParamInfo);
   }
 
-  const llvm::ArrayRef<NamedDecl*> &getDeclsInPrototypeScope() const {
+  const ArrayRef<NamedDecl *> &getDeclsInPrototypeScope() const {
     return DeclsInPrototypeScope;
   }
-  void setDeclsInPrototypeScope(llvm::ArrayRef<NamedDecl *> NewDecls);
+  void setDeclsInPrototypeScope(ArrayRef<NamedDecl *> NewDecls);
 
   /// getMinRequiredArguments - Returns the minimum number of arguments
   /// needed to call this function. This may be fewer than the number of
@@ -1838,12 +1764,9 @@ public:
     return getType()->getAs<FunctionType>()->getCallResultType(getASTContext());
   }
 
+  /// \brief Returns the storage class as written in the source. For the
+  /// computed linkage of symbol, see getLinkage.
   StorageClass getStorageClass() const { return StorageClass(SClass); }
-  void setStorageClass(StorageClass SC);
-
-  StorageClass getStorageClassAsWritten() const {
-    return StorageClass(SClassAsWritten);
-  }
 
   /// \brief Determine whether the "inline" keyword was specified for this
   /// function.
@@ -1863,7 +1786,7 @@ public:
   /// \brief Determine whether this function should be inlined, because it is
   /// either marked "inline" or "constexpr" or is a member function of a class
   /// that was defined in the class body.
-  bool isInlined() const;
+  bool isInlined() const { return IsInline; }
 
   bool isInlineDefinitionExternallyVisible() const;
 
@@ -1908,7 +1831,9 @@ public:
   /// \brief If this function is an instantiation of a member function of a
   /// class template specialization, retrieves the member specialization
   /// information.
-  MemberSpecializationInfo *getMemberSpecializationInfo() const;
+  MemberSpecializationInfo *getMemberSpecializationInfo() const {
+    return TemplateOrSpecialization.dyn_cast<MemberSpecializationInfo*>();
+  }
 
   /// \brief Specify that this record is an instantiation of the
   /// member function FD.
@@ -2472,6 +2397,12 @@ protected:
   /// possible in C++11 or Microsoft extensions mode.
   bool IsFixed : 1;
 
+  /// \brief Indicates whether it is possible for declarations of this kind
+  /// to have an out-of-date definition.
+  ///
+  /// This option is only enabled when modules are enabled.
+  bool MayHaveOutOfDateDef : 1;
+
 private:
   SourceLocation RBraceLoc;
 
@@ -2616,6 +2547,25 @@ public:
   bool isUnion()  const { return getTagKind() == TTK_Union; }
   bool isEnum()   const { return getTagKind() == TTK_Enum; }
 
+  /// Is this tag type named, either directly or via being defined in
+  /// a typedef of this type?
+  ///
+  /// C++11 [basic.link]p8:
+  ///   A type is said to have linkage if and only if:
+  ///     - it is a class or enumeration type that is named (or has a
+  ///       name for linkage purposes) and the name has linkage; ...
+  /// C++11 [dcl.typedef]p9:
+  ///   If the typedef declaration defines an unnamed class (or enum),
+  ///   the first typedef-name declared by the declaration to be that
+  ///   class type (or enum type) is used to denote the class type (or
+  ///   enum type) for linkage purposes only.
+  ///
+  /// C does not have an analogous rule, but the same concept is
+  /// nonetheless useful in some places.
+  bool hasNameForLinkage() const {
+    return (getDeclName() || getTypedefNameForAnonDecl());
+  }
+
   TypedefNameDecl *getTypedefNameForAnonDecl() const {
     return hasExtInfo() ? 0 :
            TypedefNameDeclOrQualifier.get<TypedefNameDecl*>();
@@ -2906,6 +2856,10 @@ class RecordDecl : public TagDecl {
   /// HasObjectMember - This is true if this struct has at least one member
   /// containing an Objective-C object pointer type.
   bool HasObjectMember : 1;
+  
+  /// HasVolatileMember - This is true if struct has at least one member of
+  /// 'volatile' type.
+  bool HasVolatileMember : 1;
 
   /// \brief Whether the field declarations of this record have been loaded
   /// from external storage. To avoid unnecessary deserialization of
@@ -2962,6 +2916,9 @@ public:
   bool hasObjectMember() const { return HasObjectMember; }
   void setHasObjectMember (bool val) { HasObjectMember = val; }
 
+  bool hasVolatileMember() const { return HasVolatileMember; }
+  void setHasVolatileMember (bool val) { HasVolatileMember = val; }
+  
   /// \brief Determines whether this declaration represents the
   /// injected class name.
   ///
@@ -3161,7 +3118,7 @@ public:
     assert(i < getNumParams() && "Illegal param #");
     return ParamInfo[i];
   }
-  void setParams(llvm::ArrayRef<ParmVarDecl *> NewParamInfo);
+  void setParams(ArrayRef<ParmVarDecl *> NewParamInfo);
 
   /// hasCaptures - True if this block (or its nested blocks) captures
   /// anything of local storage from its enclosing scopes.
@@ -3210,7 +3167,7 @@ public:
 ///
 /// An import declaration imports the named module (or submodule). For example:
 /// \code
-///   @__experimental_modules_import std.vector;
+///   @import std.vector;
 /// \endcode
 ///
 /// Import declarations can also be implicitly generated from
@@ -3271,7 +3228,21 @@ public:
   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
   static bool classofKind(Kind K) { return K == Import; }
 };
-  
+
+/// \brief Represents an empty-declaration.
+class EmptyDecl : public Decl {
+  virtual void anchor();
+  EmptyDecl(DeclContext *DC, SourceLocation L)
+    : Decl(Empty, DC, L) { }
+
+public:
+  static EmptyDecl *Create(ASTContext &C, DeclContext *DC,
+                           SourceLocation L);
+  static EmptyDecl *CreateDeserialized(ASTContext &C, unsigned ID);
+
+  static bool classof(const Decl *D) { return classofKind(D->getKind()); }
+  static bool classofKind(Kind K) { return K == Empty; }
+};
 
 /// Insertion operator for diagnostics.  This allows sending NamedDecl's
 /// into a diagnostic with <<.
@@ -3299,10 +3270,10 @@ void Redeclarable<decl_type>::setPreviousDeclaration(decl_type *PrevDecl) {
     // Point to previous. Make sure that this is actually the most recent
     // redeclaration, or we can build invalid chains. If the most recent
     // redeclaration is invalid, it won't be PrevDecl, but we want it anyway.
-    RedeclLink = PreviousDeclLink(
-                   llvm::cast<decl_type>(PrevDecl->getMostRecentDecl()));
     First = PrevDecl->getFirstDeclaration();
     assert(First->RedeclLink.NextIsLatest() && "Expected first");
+    decl_type *MostRecent = First->RedeclLink.getNext();
+    RedeclLink = PreviousDeclLink(cast<decl_type>(MostRecent));
   } else {
     // Make this first.
     First = static_cast<decl_type*>(this);
@@ -3310,8 +3281,8 @@ void Redeclarable<decl_type>::setPreviousDeclaration(decl_type *PrevDecl) {
 
   // First one will point to this one as latest.
   First->RedeclLink = LatestDeclLink(static_cast<decl_type*>(this));
-  if (NamedDecl *ND = dyn_cast<NamedDecl>(static_cast<decl_type*>(this)))
-    ND->ClearLinkageCache();
+  assert(!isa<NamedDecl>(static_cast<decl_type*>(this)) ||
+         cast<NamedDecl>(static_cast<decl_type*>(this))->isLinkageValid());
 }
 
 // Inline function definitions.