Standardize the reader methods in ASTReader; NFC.

There are three significant changes here:

- Most of the methods to read various embedded structures (`APInt`,
  `NestedNameSpecifier`, `DeclarationName`, etc.) have been moved
  from `ASTReader` to `ASTRecordReader`.  This cleans up quite a
  bit of code which was passing around `(F, Record, Idx)` arguments
  everywhere or doing explicit indexing, and it nicely parallels
  how it works on the writer side.  It also sets us up to then move
  most of these methods into the `BasicReader`s that I'm introducing
  as part of abstract serialization.

  As part of this, several of the top-level reader methods (e.g.
  `readTypeRecord`) have been converted to use `ASTRecordReader`
  internally, which is a nice readability improvement.

- I've standardized most of these method names on `readFoo` rather
  than `ReadFoo` (used in some of the helper structures) or `GetFoo`
  (used for some specific types for no apparent reason).

- I've changed a few of these methods to return their result instead
  of reading into an argument passed by reference.  This is partly
  for general consistency and partly because it will make the
  metaprogramming easier with abstract serialization.

Author: rjmccall

clang/include/clang/Serialization/ASTReader.h

@@ -1345,10 +1345,6 @@ class ASTReader
   };
 
   QualType readTypeRecord(unsigned Index);
-  void readExceptionSpec(ModuleFile &ModuleFile,
-                         SmallVectorImpl<QualType> &ExceptionStorage,
-                         FunctionProtoType::ExceptionSpecInfo &ESI,
-                         const RecordData &Record, unsigned &Index);
   RecordLocation TypeCursorForIndex(unsigned Index);
   void LoadedDecl(unsigned Index, Decl *D);
   Decl *ReadDeclRecord(serialization::DeclID ID);
@@ -1781,29 +1777,6 @@ class ASTReader
     return Result;
   }
 
-  /// Reads a TemplateArgumentLocInfo appropriate for the
-  /// given TemplateArgument kind.
-  TemplateArgumentLocInfo
-  GetTemplateArgumentLocInfo(ModuleFile &F, TemplateArgument::ArgKind Kind,
-                             const RecordData &Record, unsigned &Idx);
-
-  /// Reads a TemplateArgumentLoc.
-  TemplateArgumentLoc
-  ReadTemplateArgumentLoc(ModuleFile &F,
-                          const RecordData &Record, unsigned &Idx);
-
-  const ASTTemplateArgumentListInfo*
-  ReadASTTemplateArgumentListInfo(ModuleFile &F,
-                                  const RecordData &Record, unsigned &Index);
-
-  /// Reads a declarator info from the given record.
-  TypeSourceInfo *GetTypeSourceInfo(ModuleFile &F,
-                                    const RecordData &Record, unsigned &Idx);
-
-  /// Raad the type locations for the given TInfo.
-  void ReadTypeLoc(ModuleFile &F, const RecordData &Record, unsigned &Idx,
-                   TypeLoc TL);
-
   /// Resolve a type ID into a type, potentially building a new
   /// type.
   QualType GetType(serialization::TypeID ID);
@@ -2057,8 +2030,8 @@ class ASTReader
 
   IdentifierInfo *DecodeIdentifierInfo(serialization::IdentifierID ID);
 
-  IdentifierInfo *GetIdentifierInfo(ModuleFile &M, const RecordData &Record,
-                                    unsigned &Idx) {
+  IdentifierInfo *readIdentifier(ModuleFile &M, const RecordData &Record,
+                                 unsigned &Idx) {
     return DecodeIdentifierInfo(getGlobalIdentifierID(M, Record[Idx++]));
   }
 
@@ -2136,58 +2109,6 @@ class ASTReader
   serialization::SelectorID getGlobalSelectorID(ModuleFile &F,
                                                 unsigned LocalID) const;
 
-  /// Read a declaration name.
-  DeclarationName ReadDeclarationName(ModuleFile &F,
-                                      const RecordData &Record, unsigned &Idx);
-  void ReadDeclarationNameLoc(ModuleFile &F,
-                              DeclarationNameLoc &DNLoc, DeclarationName Name,
-                              const RecordData &Record, unsigned &Idx);
-  void ReadDeclarationNameInfo(ModuleFile &F, DeclarationNameInfo &NameInfo,
-                               const RecordData &Record, unsigned &Idx);
-
-  void ReadQualifierInfo(ModuleFile &F, QualifierInfo &Info,
-                         const RecordData &Record, unsigned &Idx);
-
-  NestedNameSpecifier *ReadNestedNameSpecifier(ModuleFile &F,
-                                               const RecordData &Record,
-                                               unsigned &Idx);
-
-  NestedNameSpecifierLoc ReadNestedNameSpecifierLoc(ModuleFile &F,
-                                                    const RecordData &Record,
-                                                    unsigned &Idx);
-
-  /// Read a template name.
-  TemplateName ReadTemplateName(ModuleFile &F, const RecordData &Record,
-                                unsigned &Idx);
-
-  /// Read a template argument.
-  TemplateArgument ReadTemplateArgument(ModuleFile &F, const RecordData &Record,
-                                        unsigned &Idx,
-                                        bool Canonicalize = false);
-
-  /// Read a template parameter list.
-  TemplateParameterList *ReadTemplateParameterList(ModuleFile &F,
-                                                   const RecordData &Record,
-                                                   unsigned &Idx);
-
-  /// Read a template argument array.
-  void ReadTemplateArgumentList(SmallVectorImpl<TemplateArgument> &TemplArgs,
-                                ModuleFile &F, const RecordData &Record,
-                                unsigned &Idx, bool Canonicalize = false);
-
-  /// Read a UnresolvedSet structure.
-  void ReadUnresolvedSet(ModuleFile &F, LazyASTUnresolvedSet &Set,
-                         const RecordData &Record, unsigned &Idx);
-
-  /// Read a C++ base specifier.
-  CXXBaseSpecifier ReadCXXBaseSpecifier(ModuleFile &F,
-                                        const RecordData &Record,unsigned &Idx);
-
-  /// Read a CXXCtorInitializer array.
-  CXXCtorInitializer **
-  ReadCXXCtorInitializers(ModuleFile &F, const RecordData &Record,
-                          unsigned &Idx);
-
   /// Read the contents of a CXXCtorInitializer array.
   CXXCtorInitializer **GetExternalCXXCtorInitializers(uint64_t Offset) override;
 
@@ -2227,19 +2148,6 @@ class ASTReader
   SourceRange ReadSourceRange(ModuleFile &F,
                               const RecordData &Record, unsigned &Idx);
 
-  /// Read an integral value
-  llvm::APInt ReadAPInt(const RecordData &Record, unsigned &Idx);
-
-  /// Read a signed integral value
-  llvm::APSInt ReadAPSInt(const RecordData &Record, unsigned &Idx);
-
-  /// Read a floating-point value
-  llvm::APFloat ReadAPFloat(const RecordData &Record,
-                            const llvm::fltSemantics &Sem, unsigned &Idx);
-
-  /// Read an APValue
-  APValue ReadAPValue(const RecordData &Record, unsigned &Idx);
-
   // Read a string
   static std::string ReadString(const RecordData &Record, unsigned &Idx);
 
@@ -2266,12 +2174,6 @@ class ASTReader
   CXXTemporary *ReadCXXTemporary(ModuleFile &F, const RecordData &Record,
                                  unsigned &Idx);
 
-  /// Reads one attribute from the current stream position.
-  Attr *ReadAttr(ModuleFile &M, const RecordData &Record, unsigned &Idx);
-
-  /// Reads attributes from the current stream position.
-  void ReadAttributes(ASTRecordReader &Record, AttrVec &Attrs);
-
   /// Reads a statement.
   Stmt *ReadStmt(ModuleFile &F);
 
@@ -2414,15 +2316,21 @@ class ASTRecordReader {
   /// An arbitrary index in this record.
   const uint64_t &operator[](size_t N) { return Record[N]; }
 
-  /// The last element in this record.
-  const uint64_t &back() const { return Record.back(); }
+  /// Returns the last value in this record.
+  uint64_t back() { return Record.back(); }
 
   /// Returns the current value in this record, and advances to the
   /// next value.
-  const uint64_t &readInt() { return Record[Idx++]; }
+  uint64_t readInt() { return Record[Idx++]; }
+
+  ArrayRef<uint64_t> readIntArray(unsigned Len) {
+    auto Array = llvm::makeArrayRef(Record).slice(Idx, Len);
+    Idx += Len;
+    return Array;
+  }
 
   /// Returns the current value in this record, without advancing.
-  const uint64_t &peekInt() { return Record[Idx]; }
+  uint64_t peekInt() { return Record[Idx]; }
 
   /// Skips the specified number of values.
   void skipInts(unsigned N) { Idx += N; }
@@ -2459,10 +2367,8 @@ class ASTRecordReader {
                              static_cast<ExplicitSpecKind>(Kind));
   }
 
-  void readExceptionSpec(SmallVectorImpl<QualType> &ExceptionStorage,
-                         FunctionProtoType::ExceptionSpecInfo &ESI) {
-    return Reader->readExceptionSpec(*F, ExceptionStorage, ESI, Record, Idx);
-  }
+  FunctionProtoType::ExceptionSpecInfo
+  readExceptionSpecInfo(SmallVectorImpl<QualType> &ExceptionStorage);
 
   /// Get the global offset corresponding to a local offset.
   uint64_t getGlobalBitOffset(uint32_t LocalOffset) {
@@ -2492,36 +2398,30 @@ class ASTRecordReader {
   /// Reads a TemplateArgumentLocInfo appropriate for the
   /// given TemplateArgument kind, advancing Idx.
   TemplateArgumentLocInfo
-  getTemplateArgumentLocInfo(TemplateArgument::ArgKind Kind) {
-    return Reader->GetTemplateArgumentLocInfo(*F, Kind, Record, Idx);
-  }
+  readTemplateArgumentLocInfo(TemplateArgument::ArgKind Kind);
 
   /// Reads a TemplateArgumentLoc, advancing Idx.
-  TemplateArgumentLoc
-  readTemplateArgumentLoc() {
-    return Reader->ReadTemplateArgumentLoc(*F, Record, Idx);
-  }
+  TemplateArgumentLoc readTemplateArgumentLoc();
 
   const ASTTemplateArgumentListInfo*
-  readASTTemplateArgumentListInfo() {
-    return Reader->ReadASTTemplateArgumentListInfo(*F, Record, Idx);
-  }
+  readASTTemplateArgumentListInfo();
 
   /// Reads a declarator info from the given record, advancing Idx.
-  TypeSourceInfo *getTypeSourceInfo() {
-    return Reader->GetTypeSourceInfo(*F, Record, Idx);
-  }
+  TypeSourceInfo *readTypeSourceInfo();
 
   /// Reads the location information for a type.
-  void readTypeLoc(TypeLoc TL) {
-    return Reader->ReadTypeLoc(*F, Record, Idx, TL);
-  }
+  void readTypeLoc(TypeLoc TL);
+
 
   /// Map a local type ID within a given AST file to a global type ID.
   serialization::TypeID getGlobalTypeID(unsigned LocalID) const {
     return Reader->getGlobalTypeID(*F, LocalID);
   }
 
+  Qualifiers readQualifiers() {
+    return Qualifiers::fromOpaqueValue(readInt());
+  }
+
   /// Read a type from the current position in the record.
   QualType readType() {
     return Reader->readType(*F, Record, Idx);
@@ -2550,8 +2450,8 @@ class ASTRecordReader {
     return Reader->ReadDeclAs<T>(*F, Record, Idx);
   }
 
-  IdentifierInfo *getIdentifierInfo() {
-    return Reader->GetIdentifierInfo(*F, Record, Idx);
+  IdentifierInfo *readIdentifier() {
+    return Reader->readIdentifier(*F, Record, Idx);
   }
 
   /// Read a selector from the Record, advancing Idx.
@@ -2560,64 +2460,37 @@ class ASTRecordReader {
   }
 
   /// Read a declaration name, advancing Idx.
-  DeclarationName readDeclarationName() {
-    return Reader->ReadDeclarationName(*F, Record, Idx);
-  }
-  void readDeclarationNameLoc(DeclarationNameLoc &DNLoc, DeclarationName Name) {
-    return Reader->ReadDeclarationNameLoc(*F, DNLoc, Name, Record, Idx);
-  }
-  void readDeclarationNameInfo(DeclarationNameInfo &NameInfo) {
-    return Reader->ReadDeclarationNameInfo(*F, NameInfo, Record, Idx);
-  }
+  DeclarationName readDeclarationName();
+  DeclarationNameLoc readDeclarationNameLoc(DeclarationName Name);
+  DeclarationNameInfo readDeclarationNameInfo();
 
-  void readQualifierInfo(QualifierInfo &Info) {
-    return Reader->ReadQualifierInfo(*F, Info, Record, Idx);
-  }
+  void readQualifierInfo(QualifierInfo &Info);
 
-  NestedNameSpecifier *readNestedNameSpecifier() {
-    return Reader->ReadNestedNameSpecifier(*F, Record, Idx);
-  }
+  NestedNameSpecifier *readNestedNameSpecifier();
 
-  NestedNameSpecifierLoc readNestedNameSpecifierLoc() {
-    return Reader->ReadNestedNameSpecifierLoc(*F, Record, Idx);
-  }
+  NestedNameSpecifierLoc readNestedNameSpecifierLoc();
 
   /// Read a template name, advancing Idx.
-  TemplateName readTemplateName() {
-    return Reader->ReadTemplateName(*F, Record, Idx);
-  }
+  TemplateName readTemplateName();
 
   /// Read a template argument, advancing Idx.
-  TemplateArgument readTemplateArgument(bool Canonicalize = false) {
-    return Reader->ReadTemplateArgument(*F, Record, Idx, Canonicalize);
-  }
+  TemplateArgument readTemplateArgument(bool Canonicalize = false);
 
   /// Read a template parameter list, advancing Idx.
-  TemplateParameterList *readTemplateParameterList() {
-    return Reader->ReadTemplateParameterList(*F, Record, Idx);
-  }
+  TemplateParameterList *readTemplateParameterList();
 
   /// Read a template argument array, advancing Idx.
   void readTemplateArgumentList(SmallVectorImpl<TemplateArgument> &TemplArgs,
-                                bool Canonicalize = false) {
-    return Reader->ReadTemplateArgumentList(TemplArgs, *F, Record, Idx,
-                                            Canonicalize);
-  }
+                                bool Canonicalize = false);
 
   /// Read a UnresolvedSet structure, advancing Idx.
-  void readUnresolvedSet(LazyASTUnresolvedSet &Set) {
-    return Reader->ReadUnresolvedSet(*F, Set, Record, Idx);
-  }
+  void readUnresolvedSet(LazyASTUnresolvedSet &Set);
 
   /// Read a C++ base specifier, advancing Idx.
-  CXXBaseSpecifier readCXXBaseSpecifier() {
-    return Reader->ReadCXXBaseSpecifier(*F, Record, Idx);
-  }
+  CXXBaseSpecifier readCXXBaseSpecifier();
 
   /// Read a CXXCtorInitializer array, advancing Idx.
-  CXXCtorInitializer **readCXXCtorInitializers() {
-    return Reader->ReadCXXCtorInitializers(*F, Record, Idx);
-  }
+  CXXCtorInitializer **readCXXCtorInitializers();
 
   CXXTemporary *readCXXTemporary() {
     return Reader->ReadCXXTemporary(*F, Record, Idx);
@@ -2633,22 +2506,20 @@ class ASTRecordReader {
     return Reader->ReadSourceRange(*F, Record, Idx);
   }
 
-  APValue readAPValue() { return Reader->ReadAPValue(Record, Idx); }
+  /// Read an arbitrary constant value, advancing Idx.
+  APValue readAPValue();
 
   /// Read an integral value, advancing Idx.
-  llvm::APInt readAPInt() {
-    return Reader->ReadAPInt(Record, Idx);
-  }
+  llvm::APInt readAPInt();
 
   /// Read a signed integral value, advancing Idx.
-  llvm::APSInt readAPSInt() {
-    return Reader->ReadAPSInt(Record, Idx);
-  }
+  llvm::APSInt readAPSInt();
 
   /// Read a floating-point value, advancing Idx.
-  llvm::APFloat readAPFloat(const llvm::fltSemantics &Sem) {
-    return Reader->ReadAPFloat(Record, Sem,Idx);
-  }
+  llvm::APFloat readAPFloat(const llvm::fltSemantics &Sem);
+
+  /// Read a boolean value, advancing Idx.
+  bool readBool() { return readInt() != 0; }
 
   /// Read a string, advancing Idx.
   std::string readString() {
@@ -2666,14 +2537,10 @@ class ASTRecordReader {
   }
 
   /// Reads one attribute from the current stream position, advancing Idx.
-  Attr *readAttr() {
-    return Reader->ReadAttr(*F, Record, Idx);
-  }
+  Attr *readAttr();
 
   /// Reads attributes from the current stream position, advancing Idx.
-  void readAttributes(AttrVec &Attrs) {
-    return Reader->ReadAttributes(*this, Attrs);
-  }
+  void readAttributes(AttrVec &Attrs);
 
   /// Reads a token out of a record, advancing Idx.
   Token readToken() {