text: //===- ASTBitCodes.h - Enum values for the PCH bitcode format ---*- C++ -*-===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This header defines Bitcode enum values for Clang serialized AST files.
  //
  // The enum values defined in this file should be considered permanent.  If
  // new features are added, they should have values added at the end of the
  // respective lists.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_CLANG_SERIALIZATION_ASTBITCODES_H
  #define LLVM_CLANG_SERIALIZATION_ASTBITCODES_H
  
  #include "clang/AST/DeclarationName.h"
  #include "clang/AST/Type.h"
  #include "clang/Basic/IdentifierTable.h"
  #include "clang/Basic/OperatorKinds.h"
  #include "clang/Basic/SourceLocation.h"
  #include "llvm/ADT/DenseMapInfo.h"
  #include "llvm/Bitstream/BitCodes.h"
  #include <cassert>
  #include <cstdint>
  
  namespace clang {
  namespace serialization {
  
      /// AST file major version number supported by this version of
      /// Clang.
      ///
      /// Whenever the AST file format changes in a way that makes it
      /// incompatible with previous versions (such that a reader
      /// designed for the previous version could not support reading
      /// the new version), this number should be increased.
      ///
      /// Version 4 of AST files also requires that the version control branch and
      /// revision match exactly, since there is no backward compatibility of
      /// AST files at this time.
      const unsigned VERSION_MAJOR = 8;
  
      /// AST file minor version number supported by this version of
      /// Clang.
      ///
      /// Whenever the AST format changes in a way that is still
      /// compatible with previous versions (such that a reader designed
      /// for the previous version could still support reading the new
      /// version by ignoring new kinds of subblocks), this number
      /// should be increased.
      const unsigned VERSION_MINOR = 0;
  
      /// An ID number that refers to an identifier in an AST file.
      ///
      /// The ID numbers of identifiers are consecutive (in order of discovery)
      /// and start at 1. 0 is reserved for NULL.
      using IdentifierID = uint32_t;
  
      /// An ID number that refers to a declaration in an AST file.
      ///
      /// The ID numbers of declarations are consecutive (in order of
      /// discovery), with values below NUM_PREDEF_DECL_IDS being reserved.
      /// At the start of a chain of precompiled headers, declaration ID 1 is
      /// used for the translation unit declaration.
      using DeclID = uint32_t;
  
      // FIXME: Turn these into classes so we can have some type safety when
      // we go from local ID to global and vice-versa.
      using LocalDeclID = DeclID;
      using GlobalDeclID = DeclID;
  
      /// An ID number that refers to a type in an AST file.
      ///
      /// The ID of a type is partitioned into two parts: the lower
      /// three bits are used to store the const/volatile/restrict
      /// qualifiers (as with QualType) and the upper bits provide a
      /// type index. The type index values are partitioned into two
      /// sets. The values below NUM_PREDEF_TYPE_IDs are predefined type
      /// IDs (based on the PREDEF_TYPE_*_ID constants), with 0 as a
      /// placeholder for "no type". Values from NUM_PREDEF_TYPE_IDs are
      /// other types that have serialized representations.
      using TypeID = uint32_t;
  
      /// A type index; the type ID with the qualifier bits removed.
      class TypeIdx {
        uint32_t Idx = 0;
  
      public:
        TypeIdx() = default;
        explicit TypeIdx(uint32_t index) : Idx(index) {}
  
        uint32_t getIndex() const { return Idx; }
  
        TypeID asTypeID(unsigned FastQuals) const {
          if (Idx == uint32_t(-1))
            return TypeID(-1);
  
          return (Idx << Qualifiers::FastWidth) | FastQuals;
        }
  
        static TypeIdx fromTypeID(TypeID ID) {
          if (ID == TypeID(-1))
            return TypeIdx(-1);
  
          return TypeIdx(ID >> Qualifiers::FastWidth);
        }
      };
  
      /// A structure for putting "fast"-unqualified QualTypes into a
      /// DenseMap.  This uses the standard pointer hash function.
      struct UnsafeQualTypeDenseMapInfo {
        static bool isEqual(QualType A, QualType B) { return A == B; }
  
        static QualType getEmptyKey() {
          return QualType::getFromOpaquePtr((void*) 1);
        }
  
        static QualType getTombstoneKey() {
          return QualType::getFromOpaquePtr((void*) 2);
        }
  
        static unsigned getHashValue(QualType T) {
          assert(!T.getLocalFastQualifiers() &&
                 "hash invalid for types with fast quals");
          uintptr_t v = reinterpret_cast<uintptr_t>(T.getAsOpaquePtr());
          return (unsigned(v) >> 4) ^ (unsigned(v) >> 9);
        }
      };
  
      /// An ID number that refers to an identifier in an AST file.
      using IdentID = uint32_t;
  
      /// The number of predefined identifier IDs.
      const unsigned int NUM_PREDEF_IDENT_IDS = 1;
  
      /// An ID number that refers to a macro in an AST file.
      using MacroID = uint32_t;
  
      /// A global ID number that refers to a macro in an AST file.
      using GlobalMacroID = uint32_t;
  
      /// A local to a module ID number that refers to a macro in an
      /// AST file.
      using LocalMacroID = uint32_t;
  
      /// The number of predefined macro IDs.
      const unsigned int NUM_PREDEF_MACRO_IDS = 1;
  
      /// An ID number that refers to an ObjC selector in an AST file.
      using SelectorID = uint32_t;
  
      /// The number of predefined selector IDs.
      const unsigned int NUM_PREDEF_SELECTOR_IDS = 1;
  
      /// An ID number that refers to a set of CXXBaseSpecifiers in an
      /// AST file.
      using CXXBaseSpecifiersID = uint32_t;
  
      /// An ID number that refers to a list of CXXCtorInitializers in an
      /// AST file.
      using CXXCtorInitializersID = uint32_t;
  
      /// An ID number that refers to an entity in the detailed
      /// preprocessing record.
      using PreprocessedEntityID = uint32_t;
  
      /// An ID number that refers to a submodule in a module file.
      using SubmoduleID = uint32_t;
  
      /// The number of predefined submodule IDs.
      const unsigned int NUM_PREDEF_SUBMODULE_IDS = 1;
  
      /// Source range/offset of a preprocessed entity.
      struct PPEntityOffset {
        /// Raw source location of beginning of range.
        unsigned Begin;
  
        /// Raw source location of end of range.
        unsigned End;
  
        /// Offset in the AST file.
        uint32_t BitOffset;
  
        PPEntityOffset(SourceRange R, uint32_t BitOffset)
          : Begin(R.getBegin().getRawEncoding()),
            End(R.getEnd().getRawEncoding()), BitOffset(BitOffset) {}
  
        SourceLocation getBegin() const {
          return SourceLocation::getFromRawEncoding(Begin);
        }
  
        SourceLocation getEnd() const {
          return SourceLocation::getFromRawEncoding(End);
        }
      };
  
      /// Source range of a skipped preprocessor region
      struct PPSkippedRange {
        /// Raw source location of beginning of range.
        unsigned Begin;
        /// Raw source location of end of range.
        unsigned End;
  
        PPSkippedRange(SourceRange R)
          : Begin(R.getBegin().getRawEncoding()),
            End(R.getEnd().getRawEncoding()) { }
  
        SourceLocation getBegin() const {
          return SourceLocation::getFromRawEncoding(Begin);
        }
        SourceLocation getEnd() const {
          return SourceLocation::getFromRawEncoding(End);
        }
      };
  
      /// Source range/offset of a preprocessed entity.
      struct DeclOffset {
        /// Raw source location.
        unsigned Loc = 0;
  
        /// Offset in the AST file.
        uint32_t BitOffset = 0;
  
        DeclOffset() = default;
        DeclOffset(SourceLocation Loc, uint32_t BitOffset)
          : Loc(Loc.getRawEncoding()), BitOffset(BitOffset) {}
  
        void setLocation(SourceLocation L) {
          Loc = L.getRawEncoding();
        }
  
        SourceLocation getLocation() const {
          return SourceLocation::getFromRawEncoding(Loc);
        }
      };
  
      /// The number of predefined preprocessed entity IDs.
      const unsigned int NUM_PREDEF_PP_ENTITY_IDS = 1;
  
      /// Describes the various kinds of blocks that occur within
      /// an AST file.
      enum BlockIDs {
        /// The AST block, which acts as a container around the
        /// full AST block.
        AST_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID,
  
        /// The block containing information about the source
        /// manager.
        SOURCE_MANAGER_BLOCK_ID,
  
        /// The block containing information about the
        /// preprocessor.
        PREPROCESSOR_BLOCK_ID,
  
        /// The block containing the definitions of all of the
        /// types and decls used within the AST file.
        DECLTYPES_BLOCK_ID,
  
        /// The block containing the detailed preprocessing record.
        PREPROCESSOR_DETAIL_BLOCK_ID,
  
        /// The block containing the submodule structure.
        SUBMODULE_BLOCK_ID,
  
        /// The block containing comments.
        COMMENTS_BLOCK_ID,
  
        /// The control block, which contains all of the
        /// information that needs to be validated prior to committing
        /// to loading the AST file.
        CONTROL_BLOCK_ID,
  
        /// The block of input files, which were used as inputs
        /// to create this AST file.
        ///
        /// This block is part of the control block.
        INPUT_FILES_BLOCK_ID,
  
        /// The block of configuration options, used to check that
        /// a module is being used in a configuration compatible with the
        /// configuration in which it was built.
        ///
        /// This block is part of the control block.
        OPTIONS_BLOCK_ID,
  
        /// A block containing a module file extension.
        EXTENSION_BLOCK_ID,
  
        /// A block with unhashed content.
        ///
        /// These records should not change the \a ASTFileSignature.  See \a
        /// UnhashedControlBlockRecordTypes for the list of records.
        UNHASHED_CONTROL_BLOCK_ID,
      };
  
      /// Record types that occur within the control block.
      enum ControlRecordTypes {
        /// AST file metadata, including the AST file version number
        /// and information about the compiler used to build this AST file.
        METADATA = 1,
  
        /// Record code for the list of other AST files imported by
        /// this AST file.
        IMPORTS,
  
        /// Record code for the original file that was used to
        /// generate the AST file, including both its file ID and its
        /// name.
        ORIGINAL_FILE,
  
        /// The directory that the PCH was originally created in.
        ORIGINAL_PCH_DIR,
  
        /// Record code for file ID of the file or buffer that was used to
        /// generate the AST file.
        ORIGINAL_FILE_ID,
  
        /// Offsets into the input-files block where input files
        /// reside.
        INPUT_FILE_OFFSETS,
  
        /// Record code for the module name.
        MODULE_NAME,
  
        /// Record code for the module map file that was used to build this
        /// AST file.
        MODULE_MAP_FILE,
  
        /// Record code for the module build directory.
        MODULE_DIRECTORY,
      };
  
      /// Record types that occur within the options block inside
      /// the control block.
      enum OptionsRecordTypes {
        /// Record code for the language options table.
        ///
        /// The record with this code contains the contents of the
        /// LangOptions structure. We serialize the entire contents of
        /// the structure, and let the reader decide which options are
        /// actually important to check.
        LANGUAGE_OPTIONS = 1,
  
        /// Record code for the target options table.
        TARGET_OPTIONS,
  
        /// Record code for the filesystem options table.
        FILE_SYSTEM_OPTIONS,
  
        /// Record code for the headers search options table.
        HEADER_SEARCH_OPTIONS,
  
        /// Record code for the preprocessor options table.
        PREPROCESSOR_OPTIONS,
      };
  
      /// Record codes for the unhashed control block.
      enum UnhashedControlBlockRecordTypes {
        /// Record code for the signature that identifiers this AST file.
        SIGNATURE = 1,
  
        /// Record code for the diagnostic options table.
        DIAGNOSTIC_OPTIONS,
  
        /// Record code for \#pragma diagnostic mappings.
        DIAG_PRAGMA_MAPPINGS,
      };
  
      /// Record code for extension blocks.
      enum ExtensionBlockRecordTypes {
        /// Metadata describing this particular extension.
        EXTENSION_METADATA = 1,
  
        /// The first record ID allocated to the extensions themselves.
        FIRST_EXTENSION_RECORD_ID = 4
      };
  
      /// Record types that occur within the input-files block
      /// inside the control block.
      enum InputFileRecordTypes {
        /// An input file.
        INPUT_FILE = 1,
  
        /// The input file content hash
        INPUT_FILE_HASH
      };
  
      /// Record types that occur within the AST block itself.
      enum ASTRecordTypes {
        /// Record code for the offsets of each type.
        ///
        /// The TYPE_OFFSET constant describes the record that occurs
        /// within the AST block. The record itself is an array of offsets that
        /// point into the declarations and types block (identified by
        /// DECLTYPES_BLOCK_ID). The index into the array is based on the ID
        /// of a type. For a given type ID @c T, the lower three bits of
        /// @c T are its qualifiers (const, volatile, restrict), as in
        /// the QualType class. The upper bits, after being shifted and
        /// subtracting NUM_PREDEF_TYPE_IDS, are used to index into the
        /// TYPE_OFFSET block to determine the offset of that type's
        /// corresponding record within the DECLTYPES_BLOCK_ID block.
        TYPE_OFFSET = 1,
  
        /// Record code for the offsets of each decl.
        ///
        /// The DECL_OFFSET constant describes the record that occurs
        /// within the block identified by DECL_OFFSETS_BLOCK_ID within
        /// the AST block. The record itself is an array of offsets that
        /// point into the declarations and types block (identified by
        /// DECLTYPES_BLOCK_ID). The declaration ID is an index into this
        /// record, after subtracting one to account for the use of
        /// declaration ID 0 for a NULL declaration pointer. Index 0 is
        /// reserved for the translation unit declaration.
        DECL_OFFSET = 2,
  
        /// Record code for the table of offsets of each
        /// identifier ID.
        ///
        /// The offset table contains offsets into the blob stored in
        /// the IDENTIFIER_TABLE record. Each offset points to the
        /// NULL-terminated string that corresponds to that identifier.
        IDENTIFIER_OFFSET = 3,
  
        /// This is so that older clang versions, before the introduction
        /// of the control block, can read and reject the newer PCH format.
        /// *DON'T CHANGE THIS NUMBER*.
        METADATA_OLD_FORMAT = 4,
  
        /// Record code for the identifier table.
        ///
        /// The identifier table is a simple blob that contains
        /// NULL-terminated strings for all of the identifiers
        /// referenced by the AST file. The IDENTIFIER_OFFSET table
        /// contains the mapping from identifier IDs to the characters
        /// in this blob. Note that the starting offsets of all of the
        /// identifiers are odd, so that, when the identifier offset
        /// table is loaded in, we can use the low bit to distinguish
        /// between offsets (for unresolved identifier IDs) and
        /// IdentifierInfo pointers (for already-resolved identifier
        /// IDs).
        IDENTIFIER_TABLE = 5,
  
        /// Record code for the array of eagerly deserialized decls.
        ///
        /// The AST file contains a list of all of the declarations that should be
        /// eagerly deserialized present within the parsed headers, stored as an
        /// array of declaration IDs. These declarations will be
        /// reported to the AST consumer after the AST file has been
        /// read, since their presence can affect the semantics of the
        /// program (e.g., for code generation).
        EAGERLY_DESERIALIZED_DECLS = 6,
  
        /// Record code for the set of non-builtin, special
        /// types.
        ///
        /// This record contains the type IDs for the various type nodes
        /// that are constructed during semantic analysis (e.g.,
        /// __builtin_va_list). The SPECIAL_TYPE_* constants provide
        /// offsets into this record.
        SPECIAL_TYPES = 7,
  
        /// Record code for the extra statistics we gather while
        /// generating an AST file.
        STATISTICS = 8,
  
        /// Record code for the array of tentative definitions.
        TENTATIVE_DEFINITIONS = 9,
  
        // ID 10 used to be for a list of extern "C" declarations.
  
        /// Record code for the table of offsets into the
        /// Objective-C method pool.
        SELECTOR_OFFSETS = 11,
  
        /// Record code for the Objective-C method pool,
        METHOD_POOL = 12,
  
        /// The value of the next __COUNTER__ to dispense.
        /// [PP_COUNTER_VALUE, Val]
        PP_COUNTER_VALUE = 13,
  
        /// Record code for the table of offsets into the block
        /// of source-location information.
        SOURCE_LOCATION_OFFSETS = 14,
  
        /// Record code for the set of source location entries
        /// that need to be preloaded by the AST reader.
        ///
        /// This set contains the source location entry for the
        /// predefines buffer and for any file entries that need to be
        /// preloaded.
        SOURCE_LOCATION_PRELOADS = 15,
  
        /// Record code for the set of ext_vector type names.
        EXT_VECTOR_DECLS = 16,
  
        /// Record code for the array of unused file scoped decls.
        UNUSED_FILESCOPED_DECLS = 17,
  
        /// Record code for the table of offsets to entries in the
        /// preprocessing record.
        PPD_ENTITIES_OFFSETS = 18,
  
        /// Record code for the array of VTable uses.
        VTABLE_USES = 19,
  
        // ID 20 used to be for a list of dynamic classes.
  
        /// Record code for referenced selector pool.
        REFERENCED_SELECTOR_POOL = 21,
  
        /// Record code for an update to the TU's lexically contained
        /// declarations.
        TU_UPDATE_LEXICAL = 22,
  
        // ID 23 used to be for a list of local redeclarations.
  
        /// Record code for declarations that Sema keeps references of.
        SEMA_DECL_REFS = 24,
  
        /// Record code for weak undeclared identifiers.
        WEAK_UNDECLARED_IDENTIFIERS = 25,
  
        /// Record code for pending implicit instantiations.
        PENDING_IMPLICIT_INSTANTIATIONS = 26,
  
        // ID 27 used to be for a list of replacement decls.
  
        /// Record code for an update to a decl context's lookup table.
        ///
        /// In practice, this should only be used for the TU and namespaces.
        UPDATE_VISIBLE = 28,
  
        /// Record for offsets of DECL_UPDATES records for declarations
        /// that were modified after being deserialized and need updates.
        DECL_UPDATE_OFFSETS = 29,
  
        // ID 30 used to be a decl update record. These are now in the DECLTYPES
        // block.
  
        // ID 31 used to be a list of offsets to DECL_CXX_BASE_SPECIFIERS records.
  
        // ID 32 used to be the code for \#pragma diagnostic mappings.
  
        /// Record code for special CUDA declarations.
        CUDA_SPECIAL_DECL_REFS = 33,
  
        /// Record code for header search information.
        HEADER_SEARCH_TABLE = 34,
  
        /// Record code for floating point \#pragma options.
        FP_PRAGMA_OPTIONS = 35,
  
        /// Record code for enabled OpenCL extensions.
        OPENCL_EXTENSIONS = 36,
  
        /// The list of delegating constructor declarations.
        DELEGATING_CTORS = 37,
  
        /// Record code for the set of known namespaces, which are used
        /// for typo correction.
        KNOWN_NAMESPACES = 38,
  
        /// Record code for the remapping information used to relate
        /// loaded modules to the various offsets and IDs(e.g., source location
        /// offests, declaration and type IDs) that are used in that module to
        /// refer to other modules.
        MODULE_OFFSET_MAP = 39,
  
        /// Record code for the source manager line table information,
        /// which stores information about \#line directives.
        SOURCE_MANAGER_LINE_TABLE = 40,
  
        /// Record code for map of Objective-C class definition IDs to the
        /// ObjC categories in a module that are attached to that class.
        OBJC_CATEGORIES_MAP = 41,
  
        /// Record code for a file sorted array of DeclIDs in a module.
        FILE_SORTED_DECLS = 42,
  
        /// Record code for an array of all of the (sub)modules that were
        /// imported by the AST file.
        IMPORTED_MODULES = 43,
  
        // ID 44 used to be a table of merged canonical declarations.
        // ID 45 used to be a list of declaration IDs of local redeclarations.
  
        /// Record code for the array of Objective-C categories (including
        /// extensions).
        ///
        /// This array can only be interpreted properly using the Objective-C
        /// categories map.
        OBJC_CATEGORIES = 46,
  
        /// Record code for the table of offsets of each macro ID.
        ///
        /// The offset table contains offsets into the blob stored in
        /// the preprocessor block. Each offset points to the corresponding
        /// macro definition.
        MACRO_OFFSET = 47,
  
        /// A list of "interesting" identifiers. Only used in C++ (where we
        /// don't normally do lookups into the serialized identifier table). These
        /// are eagerly deserialized.
        INTERESTING_IDENTIFIERS = 48,
  
        /// Record code for undefined but used functions and variables that
        /// need a definition in this TU.
        UNDEFINED_BUT_USED = 49,
  
        /// Record code for late parsed template functions.
        LATE_PARSED_TEMPLATE = 50,
  
        /// Record code for \#pragma optimize options.
        OPTIMIZE_PRAGMA_OPTIONS = 51,
  
        /// Record code for potentially unused local typedef names.
        UNUSED_LOCAL_TYPEDEF_NAME_CANDIDATES = 52,
  
        // ID 53 used to be a table of constructor initializer records.
  
        /// Delete expressions that will be analyzed later.
        DELETE_EXPRS_TO_ANALYZE = 54,
  
        /// Record code for \#pragma ms_struct options.
        MSSTRUCT_PRAGMA_OPTIONS = 55,
  
        /// Record code for \#pragma ms_struct options.
        POINTERS_TO_MEMBERS_PRAGMA_OPTIONS = 56,
  
        /// Number of unmatched #pragma clang cuda_force_host_device begin
        /// directives we've seen.
        CUDA_PRAGMA_FORCE_HOST_DEVICE_DEPTH = 57,
  
        /// Record code for types associated with OpenCL extensions.
        OPENCL_EXTENSION_TYPES = 58,
  
        /// Record code for declarations associated with OpenCL extensions.
        OPENCL_EXTENSION_DECLS = 59,
  
        MODULAR_CODEGEN_DECLS = 60,
  
        /// Record code for \#pragma pack options.
        PACK_PRAGMA_OPTIONS = 61,
  
        /// The stack of open #ifs/#ifdefs recorded in a preamble.
        PP_CONDITIONAL_STACK = 62,
  
        /// A table of skipped ranges within the preprocessing record.
        PPD_SKIPPED_RANGES = 63
      };
  
      /// Record types used within a source manager block.
      enum SourceManagerRecordTypes {
        /// Describes a source location entry (SLocEntry) for a
        /// file.
        SM_SLOC_FILE_ENTRY = 1,
  
        /// Describes a source location entry (SLocEntry) for a
        /// buffer.
        SM_SLOC_BUFFER_ENTRY = 2,
  
        /// Describes a blob that contains the data for a buffer
        /// entry. This kind of record always directly follows a
        /// SM_SLOC_BUFFER_ENTRY record or a SM_SLOC_FILE_ENTRY with an
        /// overridden buffer.
        SM_SLOC_BUFFER_BLOB = 3,
  
        /// Describes a zlib-compressed blob that contains the data for
        /// a buffer entry.
        SM_SLOC_BUFFER_BLOB_COMPRESSED = 4,
  
        /// Describes a source location entry (SLocEntry) for a
        /// macro expansion.
        SM_SLOC_EXPANSION_ENTRY = 5
      };
  
      /// Record types used within a preprocessor block.
      enum PreprocessorRecordTypes {
        // The macros in the PP section are a PP_MACRO_* instance followed by a
        // list of PP_TOKEN instances for each token in the definition.
  
        /// An object-like macro definition.
        /// [PP_MACRO_OBJECT_LIKE, IdentInfoID, SLoc, IsUsed]
        PP_MACRO_OBJECT_LIKE = 1,
  
        /// A function-like macro definition.
        /// [PP_MACRO_FUNCTION_LIKE, \<ObjectLikeStuff>, IsC99Varargs,
        /// IsGNUVarars, NumArgs, ArgIdentInfoID* ]
        PP_MACRO_FUNCTION_LIKE = 2,
  
        /// Describes one token.
        /// [PP_TOKEN, SLoc, Length, IdentInfoID, Kind, Flags]
        PP_TOKEN = 3,
  
        /// The macro directives history for a particular identifier.
        PP_MACRO_DIRECTIVE_HISTORY = 4,
  
        /// A macro directive exported by a module.
        /// [PP_MODULE_MACRO, SubmoduleID, MacroID, (Overridden SubmoduleID)*]
        PP_MODULE_MACRO = 5,
      };
  
      /// Record types used within a preprocessor detail block.
      enum PreprocessorDetailRecordTypes {
        /// Describes a macro expansion within the preprocessing record.
        PPD_MACRO_EXPANSION = 0,
  
        /// Describes a macro definition within the preprocessing record.
        PPD_MACRO_DEFINITION = 1,
  
        /// Describes an inclusion directive within the preprocessing
        /// record.
        PPD_INCLUSION_DIRECTIVE = 2
      };
  
      /// Record types used within a submodule description block.
      enum SubmoduleRecordTypes {
        /// Metadata for submodules as a whole.
        SUBMODULE_METADATA = 0,
  
        /// Defines the major attributes of a submodule, including its
        /// name and parent.
        SUBMODULE_DEFINITION = 1,
  
        /// Specifies the umbrella header used to create this module,
        /// if any.
        SUBMODULE_UMBRELLA_HEADER = 2,
  
        /// Specifies a header that falls into this (sub)module.
        SUBMODULE_HEADER = 3,
  
        /// Specifies a top-level header that falls into this (sub)module.
        SUBMODULE_TOPHEADER = 4,
  
        /// Specifies an umbrella directory.
        SUBMODULE_UMBRELLA_DIR = 5,
  
        /// Specifies the submodules that are imported by this
        /// submodule.
        SUBMODULE_IMPORTS = 6,
  
        /// Specifies the submodules that are re-exported from this
        /// submodule.
        SUBMODULE_EXPORTS = 7,
  
        /// Specifies a required feature.
        SUBMODULE_REQUIRES = 8,
  
        /// Specifies a header that has been explicitly excluded
        /// from this submodule.
        SUBMODULE_EXCLUDED_HEADER = 9,
  
        /// Specifies a library or framework to link against.
        SUBMODULE_LINK_LIBRARY = 10,
  
        /// Specifies a configuration macro for this module.
        SUBMODULE_CONFIG_MACRO = 11,
  
        /// Specifies a conflict with another module.
        SUBMODULE_CONFLICT = 12,
  
        /// Specifies a header that is private to this submodule.
        SUBMODULE_PRIVATE_HEADER = 13,
  
        /// Specifies a header that is part of the module but must be
        /// textually included.
        SUBMODULE_TEXTUAL_HEADER = 14,
  
        /// Specifies a header that is private to this submodule but
        /// must be textually included.
        SUBMODULE_PRIVATE_TEXTUAL_HEADER = 15,
  
        /// Specifies some declarations with initializers that must be
        /// emitted to initialize the module.
        SUBMODULE_INITIALIZERS = 16,
  
        /// Specifies the name of the module that will eventually
        /// re-export the entities in this module.
        SUBMODULE_EXPORT_AS = 17,
      };
  
      /// Record types used within a comments block.
      enum CommentRecordTypes {
        COMMENTS_RAW_COMMENT = 0
      };
  
      /// \defgroup ASTAST AST file AST constants
      ///
      /// The constants in this group describe various components of the
      /// abstract syntax tree within an AST file.
      ///
      /// @{
  
      /// Predefined type IDs.
      ///
      /// These type IDs correspond to predefined types in the AST
      /// context, such as built-in types (int) and special place-holder
      /// types (the \<overload> and \<dependent> type markers). Such
      /// types are never actually serialized, since they will be built
      /// by the AST context when it is created.
      enum PredefinedTypeIDs {
        /// The NULL type.
        PREDEF_TYPE_NULL_ID       = 0,
  
        /// The void type.
        PREDEF_TYPE_VOID_ID       = 1,
  
        /// The 'bool' or '_Bool' type.
        PREDEF_TYPE_BOOL_ID       = 2,
  
        /// The 'char' type, when it is unsigned.
        PREDEF_TYPE_CHAR_U_ID     = 3,
  
        /// The 'unsigned char' type.
        PREDEF_TYPE_UCHAR_ID      = 4,
  
        /// The 'unsigned short' type.
        PREDEF_TYPE_USHORT_ID     = 5,
  
        /// The 'unsigned int' type.
        PREDEF_TYPE_UINT_ID       = 6,
  
        /// The 'unsigned long' type.
        PREDEF_TYPE_ULONG_ID      = 7,
  
        /// The 'unsigned long long' type.
        PREDEF_TYPE_ULONGLONG_ID  = 8,
  
        /// The 'char' type, when it is signed.
        PREDEF_TYPE_CHAR_S_ID     = 9,
  
        /// The 'signed char' type.
        PREDEF_TYPE_SCHAR_ID      = 10,
  
        /// The C++ 'wchar_t' type.
        PREDEF_TYPE_WCHAR_ID      = 11,
  
        /// The (signed) 'short' type.
        PREDEF_TYPE_SHORT_ID      = 12,
  
        /// The (signed) 'int' type.
        PREDEF_TYPE_INT_ID        = 13,
  
        /// The (signed) 'long' type.
        PREDEF_TYPE_LONG_ID       = 14,
  
        /// The (signed) 'long long' type.
        PREDEF_TYPE_LONGLONG_ID   = 15,
  
        /// The 'float' type.
        PREDEF_TYPE_FLOAT_ID      = 16,
  
        /// The 'double' type.
        PREDEF_TYPE_DOUBLE_ID     = 17,
  
        /// The 'long double' type.
        PREDEF_TYPE_LONGDOUBLE_ID = 18,
  
        /// The placeholder type for overloaded function sets.
        PREDEF_TYPE_OVERLOAD_ID   = 19,
  
        /// The placeholder type for dependent types.
        PREDEF_TYPE_DEPENDENT_ID  = 20,
  
        /// The '__uint128_t' type.
        PREDEF_TYPE_UINT128_ID    = 21,
  
        /// The '__int128_t' type.
        PREDEF_TYPE_INT128_ID     = 22,
  
        /// The type of 'nullptr'.
        PREDEF_TYPE_NULLPTR_ID    = 23,
  
        /// The C++ 'char16_t' type.
        PREDEF_TYPE_CHAR16_ID     = 24,
  
        /// The C++ 'char32_t' type.
        PREDEF_TYPE_CHAR32_ID     = 25,
  
        /// The ObjC 'id' type.
        PREDEF_TYPE_OBJC_ID       = 26,
  
        /// The ObjC 'Class' type.
        PREDEF_TYPE_OBJC_CLASS    = 27,
  
        /// The ObjC 'SEL' type.
        PREDEF_TYPE_OBJC_SEL      = 28,
  
        /// The 'unknown any' placeholder type.
        PREDEF_TYPE_UNKNOWN_ANY   = 29,
  
        /// The placeholder type for bound member functions.
        PREDEF_TYPE_BOUND_MEMBER  = 30,
  
        /// The "auto" deduction type.
        PREDEF_TYPE_AUTO_DEDUCT   = 31,
  
        /// The "auto &&" deduction type.
        PREDEF_TYPE_AUTO_RREF_DEDUCT = 32,
  
        /// The OpenCL 'half' / ARM NEON __fp16 type.
        PREDEF_TYPE_HALF_ID       = 33,
  
        /// ARC's unbridged-cast placeholder type.
        PREDEF_TYPE_ARC_UNBRIDGED_CAST = 34,
  
        /// The pseudo-object placeholder type.
        PREDEF_TYPE_PSEUDO_OBJECT = 35,
  
        /// The placeholder type for builtin functions.
        PREDEF_TYPE_BUILTIN_FN = 36,
  
        /// OpenCL event type.
        PREDEF_TYPE_EVENT_ID      = 37,
  
        /// OpenCL clk event type.
        PREDEF_TYPE_CLK_EVENT_ID  = 38,
  
        /// OpenCL sampler type.
        PREDEF_TYPE_SAMPLER_ID    = 39,
  
        /// OpenCL queue type.
        PREDEF_TYPE_QUEUE_ID      = 40,
  
        /// OpenCL reserve_id type.
        PREDEF_TYPE_RESERVE_ID_ID = 41,
  
        /// The placeholder type for OpenMP array section.
        PREDEF_TYPE_OMP_ARRAY_SECTION = 42,
  
        /// The '__float128' type
        PREDEF_TYPE_FLOAT128_ID = 43,
  
        /// The '_Float16' type
        PREDEF_TYPE_FLOAT16_ID = 44,
  
        /// The C++ 'char8_t' type.
        PREDEF_TYPE_CHAR8_ID = 45,
  
        /// \brief The 'short _Accum' type
        PREDEF_TYPE_SHORT_ACCUM_ID    = 46,
  
        /// \brief The '_Accum' type
        PREDEF_TYPE_ACCUM_ID      = 47,
  
        /// \brief The 'long _Accum' type
        PREDEF_TYPE_LONG_ACCUM_ID = 48,
  
        /// \brief The 'unsigned short _Accum' type
        PREDEF_TYPE_USHORT_ACCUM_ID   = 49,
  
        /// \brief The 'unsigned _Accum' type
        PREDEF_TYPE_UACCUM_ID     = 50,
  
        /// \brief The 'unsigned long _Accum' type
        PREDEF_TYPE_ULONG_ACCUM_ID    = 51,
  
        /// \brief The 'short _Fract' type
        PREDEF_TYPE_SHORT_FRACT_ID = 52,
  
        /// \brief The '_Fract' type
        PREDEF_TYPE_FRACT_ID = 53,
  
        /// \brief The 'long _Fract' type
        PREDEF_TYPE_LONG_FRACT_ID = 54,
  
        /// \brief The 'unsigned short _Fract' type
        PREDEF_TYPE_USHORT_FRACT_ID = 55,
  
        /// \brief The 'unsigned _Fract' type
        PREDEF_TYPE_UFRACT_ID = 56,
  
        /// \brief The 'unsigned long _Fract' type
        PREDEF_TYPE_ULONG_FRACT_ID = 57,
  
        /// \brief The '_Sat short _Accum' type
        PREDEF_TYPE_SAT_SHORT_ACCUM_ID = 58,
  
        /// \brief The '_Sat _Accum' type
        PREDEF_TYPE_SAT_ACCUM_ID = 59,
  
        /// \brief The '_Sat long _Accum' type
        PREDEF_TYPE_SAT_LONG_ACCUM_ID = 60,
  
        /// \brief The '_Sat unsigned short _Accum' type
        PREDEF_TYPE_SAT_USHORT_ACCUM_ID = 61,
  
        /// \brief The '_Sat unsigned _Accum' type
        PREDEF_TYPE_SAT_UACCUM_ID = 62,
  
        /// \brief The '_Sat unsigned long _Accum' type
        PREDEF_TYPE_SAT_ULONG_ACCUM_ID = 63,
  
        /// \brief The '_Sat short _Fract' type
        PREDEF_TYPE_SAT_SHORT_FRACT_ID = 64,
  
        /// \brief The '_Sat _Fract' type
        PREDEF_TYPE_SAT_FRACT_ID = 65,
  
        /// \brief The '_Sat long _Fract' type
        PREDEF_TYPE_SAT_LONG_FRACT_ID = 66,
  
        /// \brief The '_Sat unsigned short _Fract' type
        PREDEF_TYPE_SAT_USHORT_FRACT_ID = 67,
  
        /// \brief The '_Sat unsigned _Fract' type
        PREDEF_TYPE_SAT_UFRACT_ID = 68,
  
        /// \brief The '_Sat unsigned long _Fract' type
        PREDEF_TYPE_SAT_ULONG_FRACT_ID = 69,
  
        /// OpenCL image types with auto numeration
  #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
        PREDEF_TYPE_##Id##_ID,
  #include "clang/Basic/OpenCLImageTypes.def"
        /// \brief OpenCL extension types with auto numeration
  #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
        PREDEF_TYPE_##Id##_ID,
  #include "clang/Basic/OpenCLExtensionTypes.def"
        // \brief SVE types with auto numeration
  #define SVE_TYPE(Name, Id, SingletonId) PREDEF_TYPE_##Id##_ID,
  #include "clang/Basic/AArch64SVEACLETypes.def"
      };
  
      /// The number of predefined type IDs that are reserved for
      /// the PREDEF_TYPE_* constants.
      ///
      /// Type IDs for non-predefined types will start at
      /// NUM_PREDEF_TYPE_IDs.
      const unsigned NUM_PREDEF_TYPE_IDS = 200;
  
      /// Record codes for each kind of type.
      ///
      /// These constants describe the type records that can occur within a
      /// block identified by DECLTYPES_BLOCK_ID in the AST file. Each
      /// constant describes a record for a specific type class in the
      /// AST. Note that DeclCode values share this code space.
      enum TypeCode {
  #define TYPE_BIT_CODE(CLASS_ID, CODE_ID, CODE_VALUE) \
        TYPE_##CODE_ID = CODE_VALUE,
  #include "clang/Serialization/TypeBitCodes.def"
  
        /// An ExtQualType record.
        TYPE_EXT_QUAL = 1
      };
  
      /// The type IDs for special types constructed by semantic
      /// analysis.
      ///
      /// The constants in this enumeration are indices into the
      /// SPECIAL_TYPES record.
      enum SpecialTypeIDs {
        /// CFConstantString type
        SPECIAL_TYPE_CF_CONSTANT_STRING          = 0,
  
        /// C FILE typedef type
        SPECIAL_TYPE_FILE                        = 1,
  
        /// C jmp_buf typedef type
        SPECIAL_TYPE_JMP_BUF                     = 2,
  
        /// C sigjmp_buf typedef type
        SPECIAL_TYPE_SIGJMP_BUF                  = 3,
  
        /// Objective-C "id" redefinition type
        SPECIAL_TYPE_OBJC_ID_REDEFINITION        = 4,
  
        /// Objective-C "Class" redefinition type
        SPECIAL_TYPE_OBJC_CLASS_REDEFINITION     = 5,
  
        /// Objective-C "SEL" redefinition type
        SPECIAL_TYPE_OBJC_SEL_REDEFINITION       = 6,
  
        /// C ucontext_t typedef type
        SPECIAL_TYPE_UCONTEXT_T                  = 7
      };
  
      /// The number of special type IDs.
      const unsigned NumSpecialTypeIDs = 8;
  
      /// Predefined declaration IDs.
      ///
      /// These declaration IDs correspond to predefined declarations in the AST
      /// context, such as the NULL declaration ID. Such declarations are never
      /// actually serialized, since they will be built by the AST context when
      /// it is created.
      enum PredefinedDeclIDs {
        /// The NULL declaration.
        PREDEF_DECL_NULL_ID = 0,
  
        /// The translation unit.
        PREDEF_DECL_TRANSLATION_UNIT_ID = 1,
  
        /// The Objective-C 'id' type.
        PREDEF_DECL_OBJC_ID_ID = 2,
  
        /// The Objective-C 'SEL' type.
        PREDEF_DECL_OBJC_SEL_ID = 3,
  
        /// The Objective-C 'Class' type.
        PREDEF_DECL_OBJC_CLASS_ID = 4,
  
        /// The Objective-C 'Protocol' type.
        PREDEF_DECL_OBJC_PROTOCOL_ID = 5,
  
        /// The signed 128-bit integer type.
        PREDEF_DECL_INT_128_ID = 6,
  
        /// The unsigned 128-bit integer type.
        PREDEF_DECL_UNSIGNED_INT_128_ID = 7,
  
        /// The internal 'instancetype' typedef.
        PREDEF_DECL_OBJC_INSTANCETYPE_ID = 8,
  
        /// The internal '__builtin_va_list' typedef.
        PREDEF_DECL_BUILTIN_VA_LIST_ID = 9,
  
        /// The internal '__va_list_tag' struct, if any.
        PREDEF_DECL_VA_LIST_TAG = 10,
  
        /// The internal '__builtin_ms_va_list' typedef.
        PREDEF_DECL_BUILTIN_MS_VA_LIST_ID = 11,
  
        /// The extern "C" context.
        PREDEF_DECL_EXTERN_C_CONTEXT_ID = 12,
  
        /// The internal '__make_integer_seq' template.
        PREDEF_DECL_MAKE_INTEGER_SEQ_ID = 13,
  
        /// The internal '__NSConstantString' typedef.
        PREDEF_DECL_CF_CONSTANT_STRING_ID = 14,
  
        /// The internal '__NSConstantString' tag type.
        PREDEF_DECL_CF_CONSTANT_STRING_TAG_ID = 15,
  
        /// The internal '__type_pack_element' template.
        PREDEF_DECL_TYPE_PACK_ELEMENT_ID = 16,
      };
  
      /// The number of declaration IDs that are predefined.
      ///
      /// For more information about predefined declarations, see the
      /// \c PredefinedDeclIDs type and the PREDEF_DECL_*_ID constants.
      const unsigned int NUM_PREDEF_DECL_IDS = 17;
  
      /// Record of updates for a declaration that was modified after
      /// being deserialized. This can occur within DECLTYPES_BLOCK_ID.
      const unsigned int DECL_UPDATES = 49;
  
      /// Record code for a list of local redeclarations of a declaration.
      /// This can occur within DECLTYPES_BLOCK_ID.
      const unsigned int LOCAL_REDECLARATIONS = 50;
  
      /// Record codes for each kind of declaration.
      ///
      /// These constants describe the declaration records that can occur within
      /// a declarations block (identified by DECLTYPES_BLOCK_ID). Each
      /// constant describes a record for a specific declaration class
      /// in the AST. Note that TypeCode values share this code space.
      enum DeclCode {
        /// A TypedefDecl record.
        DECL_TYPEDEF = 51,
        /// A TypeAliasDecl record.
  
        DECL_TYPEALIAS,
  
        /// An EnumDecl record.
        DECL_ENUM,
  
        /// A RecordDecl record.
        DECL_RECORD,
  
        /// An EnumConstantDecl record.
        DECL_ENUM_CONSTANT,
  
        /// A FunctionDecl record.
        DECL_FUNCTION,
  
        /// A ObjCMethodDecl record.
        DECL_OBJC_METHOD,
  
        /// A ObjCInterfaceDecl record.
        DECL_OBJC_INTERFACE,
  
        /// A ObjCProtocolDecl record.
        DECL_OBJC_PROTOCOL,
  
        /// A ObjCIvarDecl record.
        DECL_OBJC_IVAR,
  
        /// A ObjCAtDefsFieldDecl record.
        DECL_OBJC_AT_DEFS_FIELD,
  
        /// A ObjCCategoryDecl record.
        DECL_OBJC_CATEGORY,
  
        /// A ObjCCategoryImplDecl record.
        DECL_OBJC_CATEGORY_IMPL,
  
        /// A ObjCImplementationDecl record.
        DECL_OBJC_IMPLEMENTATION,
  
        /// A ObjCCompatibleAliasDecl record.
        DECL_OBJC_COMPATIBLE_ALIAS,
  
        /// A ObjCPropertyDecl record.
        DECL_OBJC_PROPERTY,
  
        /// A ObjCPropertyImplDecl record.
        DECL_OBJC_PROPERTY_IMPL,
  
        /// A FieldDecl record.
        DECL_FIELD,
  
        /// A MSPropertyDecl record.
        DECL_MS_PROPERTY,
  
        /// A VarDecl record.
        DECL_VAR,
  
        /// An ImplicitParamDecl record.
        DECL_IMPLICIT_PARAM,
  
        /// A ParmVarDecl record.
        DECL_PARM_VAR,
  
        /// A DecompositionDecl record.
        DECL_DECOMPOSITION,
  
        /// A BindingDecl record.
        DECL_BINDING,
  
        /// A FileScopeAsmDecl record.
        DECL_FILE_SCOPE_ASM,
  
        /// A BlockDecl record.
        DECL_BLOCK,
  
        /// A CapturedDecl record.
        DECL_CAPTURED,
  
        /// A record that stores the set of declarations that are
        /// lexically stored within a given DeclContext.
        ///
        /// The record itself is a blob that is an array of declaration IDs,
        /// in the order in which those declarations were added to the
        /// declaration context. This data is used when iterating over
        /// the contents of a DeclContext, e.g., via
        /// DeclContext::decls_begin() and DeclContext::decls_end().
        DECL_CONTEXT_LEXICAL,
  
        /// A record that stores the set of declarations that are
        /// visible from a given DeclContext.
        ///
        /// The record itself stores a set of mappings, each of which
        /// associates a declaration name with one or more declaration
        /// IDs. This data is used when performing qualified name lookup
        /// into a DeclContext via DeclContext::lookup.
        DECL_CONTEXT_VISIBLE,
  
        /// A LabelDecl record.
        DECL_LABEL,
  
        /// A NamespaceDecl record.
        DECL_NAMESPACE,
  
        /// A NamespaceAliasDecl record.
        DECL_NAMESPACE_ALIAS,
  
        /// A UsingDecl record.
        DECL_USING,
  
        /// A UsingPackDecl record.
        DECL_USING_PACK,
  
        /// A UsingShadowDecl record.
        DECL_USING_SHADOW,
  
        /// A ConstructorUsingShadowDecl record.
        DECL_CONSTRUCTOR_USING_SHADOW,
  
        /// A UsingDirecitveDecl record.
        DECL_USING_DIRECTIVE,
  
        /// An UnresolvedUsingValueDecl record.
        DECL_UNRESOLVED_USING_VALUE,
  
        /// An UnresolvedUsingTypenameDecl record.
        DECL_UNRESOLVED_USING_TYPENAME,
  
        /// A LinkageSpecDecl record.
        DECL_LINKAGE_SPEC,
  
        /// An ExportDecl record.
        DECL_EXPORT,
  
        /// A CXXRecordDecl record.
        DECL_CXX_RECORD,
  
        /// A CXXDeductionGuideDecl record.
        DECL_CXX_DEDUCTION_GUIDE,
  
        /// A CXXMethodDecl record.
        DECL_CXX_METHOD,
  
        /// A CXXConstructorDecl record.
        DECL_CXX_CONSTRUCTOR,
  
        /// A CXXDestructorDecl record.
        DECL_CXX_DESTRUCTOR,
  
        /// A CXXConversionDecl record.
        DECL_CXX_CONVERSION,
  
        /// An AccessSpecDecl record.
        DECL_ACCESS_SPEC,
  
        /// A FriendDecl record.
        DECL_FRIEND,
  
        /// A FriendTemplateDecl record.
        DECL_FRIEND_TEMPLATE,
  
        /// A ClassTemplateDecl record.
        DECL_CLASS_TEMPLATE,
  
        /// A ClassTemplateSpecializationDecl record.
        DECL_CLASS_TEMPLATE_SPECIALIZATION,
  
        /// A ClassTemplatePartialSpecializationDecl record.
        DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION,
  
        /// A VarTemplateDecl record.
        DECL_VAR_TEMPLATE,
  
        /// A VarTemplateSpecializationDecl record.
        DECL_VAR_TEMPLATE_SPECIALIZATION,
  
        /// A VarTemplatePartialSpecializationDecl record.
        DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION,
  
        /// A FunctionTemplateDecl record.
        DECL_FUNCTION_TEMPLATE,
  
        /// A TemplateTypeParmDecl record.
        DECL_TEMPLATE_TYPE_PARM,
  
        /// A NonTypeTemplateParmDecl record.
        DECL_NON_TYPE_TEMPLATE_PARM,
  
        /// A TemplateTemplateParmDecl record.
        DECL_TEMPLATE_TEMPLATE_PARM,
  
        /// A TypeAliasTemplateDecl record.
        DECL_TYPE_ALIAS_TEMPLATE,
  
        /// \brief A ConceptDecl record.
        DECL_CONCEPT,
  
        /// \brief A StaticAssertDecl record.
        DECL_STATIC_ASSERT,
  
        /// A record containing CXXBaseSpecifiers.
        DECL_CXX_BASE_SPECIFIERS,
  
        /// A record containing CXXCtorInitializers.
        DECL_CXX_CTOR_INITIALIZERS,
  
        /// A IndirectFieldDecl record.
        DECL_INDIRECTFIELD,
  
        /// A NonTypeTemplateParmDecl record that stores an expanded
        /// non-type template parameter pack.
        DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK,
  
        /// A TemplateTemplateParmDecl record that stores an expanded
        /// template template parameter pack.
        DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK,
  
        /// A ClassScopeFunctionSpecializationDecl record a class scope
        /// function specialization. (Microsoft extension).
        DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION,
  
        /// An ImportDecl recording a module import.
        DECL_IMPORT,
  
        /// An OMPThreadPrivateDecl record.
        DECL_OMP_THREADPRIVATE,
  
        /// An OMPRequiresDecl record.
        DECL_OMP_REQUIRES,
  
        /// An OMPAllocateDcl record.
        DECL_OMP_ALLOCATE,
  
        /// An EmptyDecl record.
        DECL_EMPTY,
  
        /// An LifetimeExtendedTemporaryDecl record.
        DECL_LIFETIME_EXTENDED_TEMPORARY,
  
        /// A RequiresExprBodyDecl record.
        DECL_REQUIRES_EXPR_BODY,
  
        /// An ObjCTypeParamDecl record.
        DECL_OBJC_TYPE_PARAM,
  
        /// An OMPCapturedExprDecl record.
        DECL_OMP_CAPTUREDEXPR,
  
        /// A PragmaCommentDecl record.
        DECL_PRAGMA_COMMENT,
  
        /// A PragmaDetectMismatchDecl record.
        DECL_PRAGMA_DETECT_MISMATCH,
  
        /// An OMPDeclareMapperDecl record.
        DECL_OMP_DECLARE_MAPPER,
  
        /// An OMPDeclareReductionDecl record.
        DECL_OMP_DECLARE_REDUCTION,
  
        DECL_LAST = DECL_OMP_DECLARE_REDUCTION
      };
  
      /// Record codes for each kind of statement or expression.
      ///
      /// These constants describe the records that describe statements
      /// or expressions. These records  occur within type and declarations
      /// block, so they begin with record values of 128.  Each constant
      /// describes a record for a specific statement or expression class in the
      /// AST.
      enum StmtCode {
        /// A marker record that indicates that we are at the end
        /// of an expression.
        STMT_STOP = DECL_LAST + 1,
  
        /// A NULL expression.
        STMT_NULL_PTR,
  
        /// A reference to a previously [de]serialized Stmt record.
        STMT_REF_PTR,
  
        /// A NullStmt record.
        STMT_NULL,
  
        /// A CompoundStmt record.
        STMT_COMPOUND,
  
        /// A CaseStmt record.
        STMT_CASE,
  
        /// A DefaultStmt record.
        STMT_DEFAULT,
  
        /// A LabelStmt record.
        STMT_LABEL,
  
        /// An AttributedStmt record.
        STMT_ATTRIBUTED,
  
        /// An IfStmt record.
        STMT_IF,
  
        /// A SwitchStmt record.
        STMT_SWITCH,
  
        /// A WhileStmt record.
        STMT_WHILE,
  
        /// A DoStmt record.
        STMT_DO,
  
        /// A ForStmt record.
        STMT_FOR,
  
        /// A GotoStmt record.
        STMT_GOTO,
  
        /// An IndirectGotoStmt record.
        STMT_INDIRECT_GOTO,
  
        /// A ContinueStmt record.
        STMT_CONTINUE,
  
        /// A BreakStmt record.
        STMT_BREAK,
  
        /// A ReturnStmt record.
        STMT_RETURN,
  
        /// A DeclStmt record.
        STMT_DECL,
  
        /// A CapturedStmt record.
        STMT_CAPTURED,
  
        /// A GCC-style AsmStmt record.
        STMT_GCCASM,
  
        /// A MS-style AsmStmt record.
        STMT_MSASM,
  
        /// A constant expression context.
        EXPR_CONSTANT,
  
        /// A PredefinedExpr record.
        EXPR_PREDEFINED,
  
        /// A DeclRefExpr record.
        EXPR_DECL_REF,
  
        /// An IntegerLiteral record.
        EXPR_INTEGER_LITERAL,
  
        /// A FloatingLiteral record.
        EXPR_FLOATING_LITERAL,
  
        /// An ImaginaryLiteral record.
        EXPR_IMAGINARY_LITERAL,
  
        /// A StringLiteral record.
        EXPR_STRING_LITERAL,
  
        /// A CharacterLiteral record.
        EXPR_CHARACTER_LITERAL,
  
        /// A ParenExpr record.
        EXPR_PAREN,
  
        /// A ParenListExpr record.
        EXPR_PAREN_LIST,
  
        /// A UnaryOperator record.
        EXPR_UNARY_OPERATOR,
  
        /// An OffsetOfExpr record.
        EXPR_OFFSETOF,
  
        /// A SizefAlignOfExpr record.
        EXPR_SIZEOF_ALIGN_OF,
  
        /// An ArraySubscriptExpr record.
        EXPR_ARRAY_SUBSCRIPT,
  
        /// A CallExpr record.
        EXPR_CALL,
  
        /// A MemberExpr record.
        EXPR_MEMBER,
  
        /// A BinaryOperator record.
        EXPR_BINARY_OPERATOR,
  
        /// A CompoundAssignOperator record.
        EXPR_COMPOUND_ASSIGN_OPERATOR,
  
        /// A ConditionOperator record.
        EXPR_CONDITIONAL_OPERATOR,
  
        /// An ImplicitCastExpr record.
        EXPR_IMPLICIT_CAST,
  
        /// A CStyleCastExpr record.
        EXPR_CSTYLE_CAST,
  
        /// A CompoundLiteralExpr record.
        EXPR_COMPOUND_LITERAL,
  
        /// An ExtVectorElementExpr record.
        EXPR_EXT_VECTOR_ELEMENT,
  
        /// An InitListExpr record.
        EXPR_INIT_LIST,
  
        /// A DesignatedInitExpr record.
        EXPR_DESIGNATED_INIT,
  
        /// A DesignatedInitUpdateExpr record.
        EXPR_DESIGNATED_INIT_UPDATE,
  
        /// An NoInitExpr record.
        EXPR_NO_INIT,
  
        /// An ArrayInitLoopExpr record.
        EXPR_ARRAY_INIT_LOOP,
  
        /// An ArrayInitIndexExpr record.
        EXPR_ARRAY_INIT_INDEX,
  
        /// An ImplicitValueInitExpr record.
        EXPR_IMPLICIT_VALUE_INIT,
  
        /// A VAArgExpr record.
        EXPR_VA_ARG,
  
        /// An AddrLabelExpr record.
        EXPR_ADDR_LABEL,
  
        /// A StmtExpr record.
        EXPR_STMT,
  
        /// A ChooseExpr record.
        EXPR_CHOOSE,
  
        /// A GNUNullExpr record.
        EXPR_GNU_NULL,
  
        /// A SourceLocExpr record.
        EXPR_SOURCE_LOC,
  
        /// A ShuffleVectorExpr record.
        EXPR_SHUFFLE_VECTOR,
  
        /// A ConvertVectorExpr record.
        EXPR_CONVERT_VECTOR,
  
        /// BlockExpr
        EXPR_BLOCK,
  
        /// A GenericSelectionExpr record.
        EXPR_GENERIC_SELECTION,
  
        /// A PseudoObjectExpr record.
        EXPR_PSEUDO_OBJECT,
  
        /// An AtomicExpr record.
        EXPR_ATOMIC,
  
        // Objective-C
  
        /// An ObjCStringLiteral record.
        EXPR_OBJC_STRING_LITERAL,
  
        EXPR_OBJC_BOXED_EXPRESSION,
        EXPR_OBJC_ARRAY_LITERAL,
        EXPR_OBJC_DICTIONARY_LITERAL,
  
        /// An ObjCEncodeExpr record.
        EXPR_OBJC_ENCODE,
  
        /// An ObjCSelectorExpr record.
        EXPR_OBJC_SELECTOR_EXPR,
  
        /// An ObjCProtocolExpr record.
        EXPR_OBJC_PROTOCOL_EXPR,
  
        /// An ObjCIvarRefExpr record.
        EXPR_OBJC_IVAR_REF_EXPR,
  
        /// An ObjCPropertyRefExpr record.
        EXPR_OBJC_PROPERTY_REF_EXPR,
  
        /// An ObjCSubscriptRefExpr record.
        EXPR_OBJC_SUBSCRIPT_REF_EXPR,
  
        /// UNUSED
        EXPR_OBJC_KVC_REF_EXPR,
  
        /// An ObjCMessageExpr record.
        EXPR_OBJC_MESSAGE_EXPR,
  
        /// An ObjCIsa Expr record.
        EXPR_OBJC_ISA,
  
        /// An ObjCIndirectCopyRestoreExpr record.
        EXPR_OBJC_INDIRECT_COPY_RESTORE,
  
        /// An ObjCForCollectionStmt record.
        STMT_OBJC_FOR_COLLECTION,
  
        /// An ObjCAtCatchStmt record.
        STMT_OBJC_CATCH,
  
        /// An ObjCAtFinallyStmt record.
        STMT_OBJC_FINALLY,
  
        /// An ObjCAtTryStmt record.
        STMT_OBJC_AT_TRY,
  
        /// An ObjCAtSynchronizedStmt record.
        STMT_OBJC_AT_SYNCHRONIZED,
  
        /// An ObjCAtThrowStmt record.
        STMT_OBJC_AT_THROW,
  
        /// An ObjCAutoreleasePoolStmt record.
        STMT_OBJC_AUTORELEASE_POOL,
  
        /// An ObjCBoolLiteralExpr record.
        EXPR_OBJC_BOOL_LITERAL,
  
        /// An ObjCAvailabilityCheckExpr record.
        EXPR_OBJC_AVAILABILITY_CHECK,
  
        // C++
  
        /// A CXXCatchStmt record.
        STMT_CXX_CATCH,
  
        /// A CXXTryStmt record.
        STMT_CXX_TRY,
        /// A CXXForRangeStmt record.
  
        STMT_CXX_FOR_RANGE,
  
        /// A CXXOperatorCallExpr record.
        EXPR_CXX_OPERATOR_CALL,
  
        /// A CXXMemberCallExpr record.
        EXPR_CXX_MEMBER_CALL,
  
        /// A CXXRewrittenBinaryOperator record.
        EXPR_CXX_REWRITTEN_BINARY_OPERATOR,
  
        /// A CXXConstructExpr record.
        EXPR_CXX_CONSTRUCT,
  
        /// A CXXInheritedCtorInitExpr record.
        EXPR_CXX_INHERITED_CTOR_INIT,
  
        /// A CXXTemporaryObjectExpr record.
        EXPR_CXX_TEMPORARY_OBJECT,
  
        /// A CXXStaticCastExpr record.
        EXPR_CXX_STATIC_CAST,
  
        /// A CXXDynamicCastExpr record.
        EXPR_CXX_DYNAMIC_CAST,
  
        /// A CXXReinterpretCastExpr record.
        EXPR_CXX_REINTERPRET_CAST,
  
        /// A CXXConstCastExpr record.
        EXPR_CXX_CONST_CAST,
  
        /// A CXXFunctionalCastExpr record.
        EXPR_CXX_FUNCTIONAL_CAST,
  
        /// A UserDefinedLiteral record.
        EXPR_USER_DEFINED_LITERAL,
  
        /// A CXXStdInitializerListExpr record.
        EXPR_CXX_STD_INITIALIZER_LIST,
  
        /// A CXXBoolLiteralExpr record.
        EXPR_CXX_BOOL_LITERAL,
  
        EXPR_CXX_NULL_PTR_LITERAL,  // CXXNullPtrLiteralExpr
        EXPR_CXX_TYPEID_EXPR,       // CXXTypeidExpr (of expr).
        EXPR_CXX_TYPEID_TYPE,       // CXXTypeidExpr (of type).
        EXPR_CXX_THIS,              // CXXThisExpr
        EXPR_CXX_THROW,             // CXXThrowExpr
        EXPR_CXX_DEFAULT_ARG,       // CXXDefaultArgExpr
        EXPR_CXX_DEFAULT_INIT,      // CXXDefaultInitExpr
        EXPR_CXX_BIND_TEMPORARY,    // CXXBindTemporaryExpr
  
        EXPR_CXX_SCALAR_VALUE_INIT, // CXXScalarValueInitExpr
        EXPR_CXX_NEW,               // CXXNewExpr
        EXPR_CXX_DELETE,            // CXXDeleteExpr
        EXPR_CXX_PSEUDO_DESTRUCTOR, // CXXPseudoDestructorExpr
  
        EXPR_EXPR_WITH_CLEANUPS,    // ExprWithCleanups
  
        EXPR_CXX_DEPENDENT_SCOPE_MEMBER,   // CXXDependentScopeMemberExpr
        EXPR_CXX_DEPENDENT_SCOPE_DECL_REF, // DependentScopeDeclRefExpr
        EXPR_CXX_UNRESOLVED_CONSTRUCT,     // CXXUnresolvedConstructExpr
        EXPR_CXX_UNRESOLVED_MEMBER,        // UnresolvedMemberExpr
        EXPR_CXX_UNRESOLVED_LOOKUP,        // UnresolvedLookupExpr
  
        EXPR_CXX_EXPRESSION_TRAIT,  // ExpressionTraitExpr
        EXPR_CXX_NOEXCEPT,          // CXXNoexceptExpr
  
        EXPR_OPAQUE_VALUE,          // OpaqueValueExpr
        EXPR_BINARY_CONDITIONAL_OPERATOR,  // BinaryConditionalOperator
        EXPR_TYPE_TRAIT,            // TypeTraitExpr
        EXPR_ARRAY_TYPE_TRAIT,      // ArrayTypeTraitIntExpr
  
        EXPR_PACK_EXPANSION,        // PackExpansionExpr
        EXPR_SIZEOF_PACK,           // SizeOfPackExpr
        EXPR_SUBST_NON_TYPE_TEMPLATE_PARM, // SubstNonTypeTemplateParmExpr
        EXPR_SUBST_NON_TYPE_TEMPLATE_PARM_PACK,// SubstNonTypeTemplateParmPackExpr
        EXPR_FUNCTION_PARM_PACK,    // FunctionParmPackExpr
        EXPR_MATERIALIZE_TEMPORARY, // MaterializeTemporaryExpr
        EXPR_CXX_FOLD,              // CXXFoldExpr
        EXPR_CONCEPT_SPECIALIZATION,// ConceptSpecializationExpr
        EXPR_REQUIRES,              // RequiresExpr
  
        // CUDA
        EXPR_CUDA_KERNEL_CALL,       // CUDAKernelCallExpr
  
        // OpenCL
        EXPR_ASTYPE,                 // AsTypeExpr
  
        // Microsoft
        EXPR_CXX_PROPERTY_REF_EXPR, // MSPropertyRefExpr
        EXPR_CXX_PROPERTY_SUBSCRIPT_EXPR, // MSPropertySubscriptExpr
        EXPR_CXX_UUIDOF_EXPR,       // CXXUuidofExpr (of expr).
        EXPR_CXX_UUIDOF_TYPE,       // CXXUuidofExpr (of type).
        STMT_SEH_LEAVE,             // SEHLeaveStmt
        STMT_SEH_EXCEPT,            // SEHExceptStmt
        STMT_SEH_FINALLY,           // SEHFinallyStmt
        STMT_SEH_TRY,               // SEHTryStmt
  
        // OpenMP directives
        STMT_OMP_PARALLEL_DIRECTIVE,
        STMT_OMP_SIMD_DIRECTIVE,
        STMT_OMP_FOR_DIRECTIVE,
        STMT_OMP_FOR_SIMD_DIRECTIVE,
        STMT_OMP_SECTIONS_DIRECTIVE,
        STMT_OMP_SECTION_DIRECTIVE,
        STMT_OMP_SINGLE_DIRECTIVE,
        STMT_OMP_MASTER_DIRECTIVE,
        STMT_OMP_CRITICAL_DIRECTIVE,
        STMT_OMP_PARALLEL_FOR_DIRECTIVE,
        STMT_OMP_PARALLEL_FOR_SIMD_DIRECTIVE,
        STMT_OMP_PARALLEL_MASTER_DIRECTIVE,
        STMT_OMP_PARALLEL_SECTIONS_DIRECTIVE,
        STMT_OMP_TASK_DIRECTIVE,
        STMT_OMP_TASKYIELD_DIRECTIVE,
        STMT_OMP_BARRIER_DIRECTIVE,
        STMT_OMP_TASKWAIT_DIRECTIVE,
        STMT_OMP_FLUSH_DIRECTIVE,
        STMT_OMP_ORDERED_DIRECTIVE,
        STMT_OMP_ATOMIC_DIRECTIVE,
        STMT_OMP_TARGET_DIRECTIVE,
        STMT_OMP_TARGET_DATA_DIRECTIVE,
        STMT_OMP_TARGET_ENTER_DATA_DIRECTIVE,
        STMT_OMP_TARGET_EXIT_DATA_DIRECTIVE,
        STMT_OMP_TARGET_PARALLEL_DIRECTIVE,
        STMT_OMP_TARGET_PARALLEL_FOR_DIRECTIVE,
        STMT_OMP_TEAMS_DIRECTIVE,
        STMT_OMP_TASKGROUP_DIRECTIVE,
        STMT_OMP_CANCELLATION_POINT_DIRECTIVE,
        STMT_OMP_CANCEL_DIRECTIVE,
        STMT_OMP_TASKLOOP_DIRECTIVE,
        STMT_OMP_TASKLOOP_SIMD_DIRECTIVE,
        STMT_OMP_MASTER_TASKLOOP_DIRECTIVE,
        STMT_OMP_MASTER_TASKLOOP_SIMD_DIRECTIVE,
        STMT_OMP_PARALLEL_MASTER_TASKLOOP_DIRECTIVE,
        STMT_OMP_PARALLEL_MASTER_TASKLOOP_SIMD_DIRECTIVE,
        STMT_OMP_DISTRIBUTE_DIRECTIVE,
        STMT_OMP_TARGET_UPDATE_DIRECTIVE,
        STMT_OMP_DISTRIBUTE_PARALLEL_FOR_DIRECTIVE,
        STMT_OMP_DISTRIBUTE_PARALLEL_FOR_SIMD_DIRECTIVE,
        STMT_OMP_DISTRIBUTE_SIMD_DIRECTIVE,
        STMT_OMP_TARGET_PARALLEL_FOR_SIMD_DIRECTIVE,
        STMT_OMP_TARGET_SIMD_DIRECTIVE,
        STMT_OMP_TEAMS_DISTRIBUTE_DIRECTIVE,
        STMT_OMP_TEAMS_DISTRIBUTE_SIMD_DIRECTIVE,
        STMT_OMP_TEAMS_DISTRIBUTE_PARALLEL_FOR_SIMD_DIRECTIVE,
        STMT_OMP_TEAMS_DISTRIBUTE_PARALLEL_FOR_DIRECTIVE,
        STMT_OMP_TARGET_TEAMS_DIRECTIVE,
        STMT_OMP_TARGET_TEAMS_DISTRIBUTE_DIRECTIVE,
        STMT_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_FOR_DIRECTIVE,
        STMT_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_FOR_SIMD_DIRECTIVE,
        STMT_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD_DIRECTIVE,
        EXPR_OMP_ARRAY_SECTION,
  
        // ARC
        EXPR_OBJC_BRIDGED_CAST,     // ObjCBridgedCastExpr
  
        STMT_MS_DEPENDENT_EXISTS,   // MSDependentExistsStmt
        EXPR_LAMBDA,                // LambdaExpr
        STMT_COROUTINE_BODY,
        STMT_CORETURN,
        EXPR_COAWAIT,
        EXPR_COYIELD,
        EXPR_DEPENDENT_COAWAIT,
      };
  
      /// The kinds of designators that can occur in a
      /// DesignatedInitExpr.
      enum DesignatorTypes {
        /// Field designator where only the field name is known.
        DESIG_FIELD_NAME  = 0,
  
        /// Field designator where the field has been resolved to
        /// a declaration.
        DESIG_FIELD_DECL  = 1,
  
        /// Array designator.
        DESIG_ARRAY       = 2,
  
        /// GNU array range designator.
        DESIG_ARRAY_RANGE = 3
      };
  
      /// The different kinds of data that can occur in a
      /// CtorInitializer.
      enum CtorInitializerType {
        CTOR_INITIALIZER_BASE,
        CTOR_INITIALIZER_DELEGATING,
        CTOR_INITIALIZER_MEMBER,
        CTOR_INITIALIZER_INDIRECT_MEMBER
      };
  
      /// Describes the redeclarations of a declaration.
      struct LocalRedeclarationsInfo {
        // The ID of the first declaration
        DeclID FirstID;
  
        // Offset into the array of redeclaration chains.
        unsigned Offset;
  
        friend bool operator<(const LocalRedeclarationsInfo &X,
                              const LocalRedeclarationsInfo &Y) {
          return X.FirstID < Y.FirstID;
        }
  
        friend bool operator>(const LocalRedeclarationsInfo &X,
                              const LocalRedeclarationsInfo &Y) {
          return X.FirstID > Y.FirstID;
        }
  
        friend bool operator<=(const LocalRedeclarationsInfo &X,
                               const LocalRedeclarationsInfo &Y) {
          return X.FirstID <= Y.FirstID;
        }
  
        friend bool operator>=(const LocalRedeclarationsInfo &X,
                               const LocalRedeclarationsInfo &Y) {
          return X.FirstID >= Y.FirstID;
        }
      };
  
      /// Describes the categories of an Objective-C class.
      struct ObjCCategoriesInfo {
        // The ID of the definition
        DeclID DefinitionID;
  
        // Offset into the array of category lists.
        unsigned Offset;
  
        friend bool operator<(const ObjCCategoriesInfo &X,
                              const ObjCCategoriesInfo &Y) {
          return X.DefinitionID < Y.DefinitionID;
        }
  
        friend bool operator>(const ObjCCategoriesInfo &X,
                              const ObjCCategoriesInfo &Y) {
          return X.DefinitionID > Y.DefinitionID;
        }
  
        friend bool operator<=(const ObjCCategoriesInfo &X,
                               const ObjCCategoriesInfo &Y) {
          return X.DefinitionID <= Y.DefinitionID;
        }
  
        friend bool operator>=(const ObjCCategoriesInfo &X,
                               const ObjCCategoriesInfo &Y) {
          return X.DefinitionID >= Y.DefinitionID;
        }
      };
  
      /// A key used when looking up entities by \ref DeclarationName.
      ///
      /// Different \ref DeclarationNames are mapped to different keys, but the
      /// same key can occasionally represent multiple names (for names that
      /// contain types, in particular).
      class DeclarationNameKey {
        using NameKind = unsigned;
  
        NameKind Kind = 0;
        uint64_t Data = 0;
  
      public:
        DeclarationNameKey() = default;
        DeclarationNameKey(DeclarationName Name);
        DeclarationNameKey(NameKind Kind, uint64_t Data)
            : Kind(Kind), Data(Data) {}
  
        NameKind getKind() const { return Kind; }
  
        IdentifierInfo *getIdentifier() const {
          assert(Kind == DeclarationName::Identifier ||
                 Kind == DeclarationName::CXXLiteralOperatorName ||
                 Kind == DeclarationName::CXXDeductionGuideName);
          return (IdentifierInfo *)Data;
        }
  
        Selector getSelector() const {
          assert(Kind == DeclarationName::ObjCZeroArgSelector ||
                 Kind == DeclarationName::ObjCOneArgSelector ||
                 Kind == DeclarationName::ObjCMultiArgSelector);
          return Selector(Data);
        }
  
        OverloadedOperatorKind getOperatorKind() const {
          assert(Kind == DeclarationName::CXXOperatorName);
          return (OverloadedOperatorKind)Data;
        }
  
        /// Compute a fingerprint of this key for use in on-disk hash table.
        unsigned getHash() const;
  
        friend bool operator==(const DeclarationNameKey &A,
                               const DeclarationNameKey &B) {
          return A.Kind == B.Kind && A.Data == B.Data;
        }
      };
  
      /// @}
  
  } // namespace serialization
  } // namespace clang
  
  namespace llvm {
  
    template <> struct DenseMapInfo<clang::serialization::DeclarationNameKey> {
      static clang::serialization::DeclarationNameKey getEmptyKey() {
        return clang::serialization::DeclarationNameKey(-1, 1);
      }
  
      static clang::serialization::DeclarationNameKey getTombstoneKey() {
        return clang::serialization::DeclarationNameKey(-1, 2);
      }
  
      static unsigned
      getHashValue(const clang::serialization::DeclarationNameKey &Key) {
        return Key.getHash();
      }
  
      static bool isEqual(const clang::serialization::DeclarationNameKey &L,
                          const clang::serialization::DeclarationNameKey &R) {
        return L == R;
      }
    };
  
  } // namespace llvm
  
  #endif // LLVM_CLANG_SERIALIZATION_ASTBITCODES_H
  