path: root/include/clang/Serialization/ASTWriter.h

//===--- ASTWriter.h - AST File Writer --------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file defines the ASTWriter class, which writes an AST file
//  containing a serialized representation of a translation unit.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_FRONTEND_AST_WRITER_H
#define LLVM_CLANG_FRONTEND_AST_WRITER_H

#include "clang/AST/Decl.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/Serialization/ASTBitCodes.h"
#include "clang/Serialization/ASTDeserializationListener.h"
#include "clang/Sema/SemaConsumer.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Bitcode/BitstreamWriter.h"
#include <map>
#include <queue>
#include <vector>

namespace llvm {
  class APFloat;
  class APInt;
  class BitstreamWriter;
}

namespace clang {

class ASTContext;
class NestedNameSpecifier;
class CXXBaseSpecifier;
class CXXBaseOrMemberInitializer;
class LabelStmt;
class MacroDefinition;
class MemorizeStatCalls;
class ASTReader;
class Preprocessor;
class Sema;
class SourceManager;
class SwitchCase;
class TargetInfo;

/// \brief Writes an AST file containing the contents of a translation unit.
///
/// The ASTWriter class produces a bitstream containing the serialized
/// representation of a given abstract syntax tree and its supporting
/// data structures. This bitstream can be de-serialized via an
/// instance of the ASTReader class.
class ASTWriter : public ASTDeserializationListener,
                  public ASTMutationListener {
public:
  typedef llvm::SmallVector<uint64_t, 64> RecordData;
  typedef llvm::SmallVectorImpl<uint64_t> RecordDataImpl;

  friend class ASTDeclWriter;
private:
  /// \brief The bitstream writer used to emit this precompiled header.
  llvm::BitstreamWriter &Stream;

  /// \brief The reader of existing AST files, if we're chaining.
  ASTReader *Chain;

  /// \brief Stores a declaration or a type to be written to the AST file.
  class DeclOrType {
  public:
    DeclOrType(Decl *D) : Stored(D), IsType(false) { }
    DeclOrType(QualType T) : Stored(T.getAsOpaquePtr()), IsType(true) { }
    
    bool isType() const { return IsType; }
    bool isDecl() const { return !IsType; }
    
    QualType getType() const {
      assert(isType() && "Not a type!");
      return QualType::getFromOpaquePtr(Stored);
    }
    
    Decl *getDecl() const {
      assert(isDecl() && "Not a decl!");
      return static_cast<Decl *>(Stored);
    }
    
  private:
    void *Stored;
    bool IsType;
  };

  /// \brief The declarations and types to emit.
  std::queue<DeclOrType> DeclTypesToEmit;

  /// \brief The first ID number we can use for our own declarations.
  serialization::DeclID FirstDeclID;

  /// \brief The decl ID that will be assigned to the next new decl.
  serialization::DeclID NextDeclID;

  /// \brief Map that provides the ID numbers of each declaration within
  /// the output stream, as well as those deserialized from a chained PCH.
  ///
  /// The ID numbers of declarations are consecutive (in order of
  /// discovery) and start at 2. 1 is reserved for the translation
  /// unit, while 0 is reserved for NULL.
  llvm::DenseMap<const Decl *, serialization::DeclID> DeclIDs;

  /// \brief Offset of each declaration in the bitstream, indexed by
  /// the declaration's ID.
  std::vector<uint32_t> DeclOffsets;

  /// \brief The first ID number we can use for our own types.
  serialization::TypeID FirstTypeID;

  /// \brief The type ID that will be assigned to the next new type.
  serialization::TypeID NextTypeID;

  /// \brief Map that provides the ID numbers of each type within the
  /// output stream, plus those deserialized from a chained PCH.
  ///
  /// The ID numbers of types are consecutive (in order of discovery)
  /// and start at 1. 0 is reserved for NULL. When types are actually
  /// stored in the stream, the ID number is shifted by 2 bits to
  /// allow for the const/volatile qualifiers.
  ///
  /// Keys in the map never have const/volatile qualifiers.
  serialization::TypeIdxMap TypeIdxs;

  /// \brief Offset of each type in the bitstream, indexed by
  /// the type's ID.
  std::vector<uint32_t> TypeOffsets;

  /// \brief The first ID number we can use for our own identifiers.
  serialization::IdentID FirstIdentID;

  /// \brief The identifier ID that will be assigned to the next new identifier.
  serialization::IdentID NextIdentID;

  /// \brief Map that provides the ID numbers of each identifier in
  /// the output stream.
  ///
  /// The ID numbers for identifiers are consecutive (in order of
  /// discovery), starting at 1. An ID of zero refers to a NULL
  /// IdentifierInfo.
  llvm::DenseMap<const IdentifierInfo *, serialization::IdentID> IdentifierIDs;

  /// \brief Offsets of each of the identifier IDs into the identifier
  /// table.
  std::vector<uint32_t> IdentifierOffsets;

  /// \brief The first ID number we can use for our own selectors.
  serialization::SelectorID FirstSelectorID;

  /// \brief The selector ID that will be assigned to the next new identifier.
  serialization::SelectorID NextSelectorID;

  /// \brief Map that provides the ID numbers of each Selector.
  llvm::DenseMap<Selector, serialization::SelectorID> SelectorIDs;

  /// \brief Offset of each selector within the method pool/selector
  /// table, indexed by the Selector ID (-1).
  std::vector<uint32_t> SelectorOffsets;
  
  /// \brief Offsets of each of the macro identifiers into the
  /// bitstream.
  ///
  /// For each identifier that is associated with a macro, this map
  /// provides the offset into the bitstream where that macro is
  /// defined.
  llvm::DenseMap<const IdentifierInfo *, uint64_t> MacroOffsets;

  /// \brief The first ID number we can use for our own macro definitions.
  serialization::MacroID FirstMacroID;
  
  /// \brief The decl ID that will be assigned to the next new macro definition.
  serialization::MacroID NextMacroID;
  
  /// \brief Mapping from macro definitions (as they occur in the preprocessing
  /// record) to the macro IDs.
  llvm::DenseMap<const MacroDefinition *, serialization::MacroID>
      MacroDefinitions;
  
  /// \brief Mapping from the macro definition indices in \c MacroDefinitions
  /// to the corresponding offsets within the preprocessor block.
  std::vector<uint32_t> MacroDefinitionOffsets;

  typedef llvm::SmallVector<uint64_t, 2> UpdateRecord;
  typedef llvm::DenseMap<const Decl *, UpdateRecord> DeclUpdateMap;
  /// \brief Mapping from declarations that came from a chained PCH to the
  /// record containing modifications to them.
  DeclUpdateMap DeclUpdates;

  typedef llvm::DenseMap<Decl *, Decl *> FirstLatestDeclMap;
  /// \brief Map of first declarations from a chained PCH that point to the
  /// most recent declarations in another PCH.
  FirstLatestDeclMap FirstLatestDecls;
  
  /// \brief Declarations encountered that might be external
  /// definitions.
  ///
  /// We keep track of external definitions (as well as tentative
  /// definitions) as we are emitting declarations to the AST
  /// file. The AST file contains a separate record for these external
  /// definitions, which are provided to the AST consumer by the AST
  /// reader. This is behavior is required to properly cope with,
  /// e.g., tentative variable definitions that occur within
  /// headers. The declarations themselves are stored as declaration
  /// IDs, since they will be written out to an EXTERNAL_DEFINITIONS
  /// record.
  llvm::SmallVector<uint64_t, 16> ExternalDefinitions;

  /// \brief Namespaces that have received extensions since their serialized
  /// form.
  ///
  /// Basically, when we're chaining and encountering a namespace, we check if
  /// its primary namespace comes from the chain. If it does, we add the primary
  /// to this set, so that we can write out lexical content updates for it.
  llvm::SmallPtrSet<const NamespaceDecl *, 16> UpdatedNamespaces;

  typedef llvm::SmallPtrSet<const Decl *, 16> DeclsToRewriteTy;
  /// \brief Decls that will be replaced in the current dependent AST file.
  DeclsToRewriteTy DeclsToRewrite;

  /// \brief Decls that have been replaced in the current dependent AST file.
  ///
  /// When a decl changes fundamentally after being deserialized (this shouldn't
  /// happen, but the ObjC AST nodes are designed this way), it will be
  /// serialized again. In this case, it is registered here, so that the reader
  /// knows to read the updated version.
  llvm::SmallVector<std::pair<serialization::DeclID, uint64_t>, 16>
      ReplacedDecls;

  typedef llvm::SmallVector<serialization::DeclID, 4>
      AdditionalTemplateSpecializationsList;
  typedef llvm::DenseMap<serialization::DeclID,
                         AdditionalTemplateSpecializationsList>
      AdditionalTemplateSpecializationsMap;

  /// \brief Additional specializations (including partial) of templates that
  /// were introduced after the template was serialized.
  AdditionalTemplateSpecializationsMap AdditionalTemplateSpecializations;

  /// \brief Statements that we've encountered while serializing a
  /// declaration or type.
  llvm::SmallVector<Stmt *, 16> StmtsToEmit;

  /// \brief Statements collection to use for ASTWriter::AddStmt().
  /// It will point to StmtsToEmit unless it is overriden. 
  llvm::SmallVector<Stmt *, 16> *CollectedStmts;

  /// \brief Mapping from SwitchCase statements to IDs.
  std::map<SwitchCase *, unsigned> SwitchCaseIDs;

  /// \brief Mapping from LabelStmt statements to IDs.
  std::map<LabelStmt *, unsigned> LabelIDs;

  /// \brief The number of statements written to the AST file.
  unsigned NumStatements;

  /// \brief The number of macros written to the AST file.
  unsigned NumMacros;

  /// \brief The number of lexical declcontexts written to the AST
  /// file.
  unsigned NumLexicalDeclContexts;

  /// \brief The number of visible declcontexts written to the AST
  /// file.
  unsigned NumVisibleDeclContexts;

  /// \brief Write the given subexpression to the bitstream.
  void WriteSubStmt(Stmt *S);

  void WriteBlockInfoBlock();
  void WriteMetadata(ASTContext &Context, const char *isysroot);
  void WriteLanguageOptions(const LangOptions &LangOpts);
  void WriteStatCache(MemorizeStatCalls &StatCalls);
  void WriteSourceManagerBlock(SourceManager &SourceMgr,
                               const Preprocessor &PP,
                               const char* isysroot);
  void WritePreprocessor(const Preprocessor &PP);
  void WriteType(QualType T);
  uint64_t WriteDeclContextLexic