//===--- 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/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:
  typedef llvm::SmallVector<uint64_t, 64> RecordData;

  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 Mapping from macro definitions (as they occur in the preprocessing
  /// record) to the index into the macro definitions table.
  llvm::DenseMap<const MacroDefinition *, serialization::IdentID>
      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::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;

  /// \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 WriteDeclContextLexicalBlock(ASTContext &Context, DeclContext *DC);
  uint64_t WriteDeclContextVisibleBlock(ASTContext &Context, DeclContext *DC);
  void WriteTypeDeclOffsets();
  void WriteSelectors(Sema &SemaRef);
  void WriteReferencedSelectorsPool(Sema &SemaRef);
  void WriteIdentifierTable(Preprocessor &PP);
  void WriteAttributeRecord(const AttrVec &Attrs);
  void WriteDeclUpdateBlock();
  void WriteDeclContextVisibleUpdate(const DeclContext *DC);
  void WriteAdditionalTemplateSpecializations();

  unsigned ParmVarDeclAbbrev;
  unsigned DeclContextLexicalAbbrev;
  unsigned DeclContextVisibleLookupAbbrev;
  unsigned UpdateVisibleAbbrev;
  void WriteDeclsBlockAbbrevs();
  void WriteDecl(ASTContext &Context, Decl *D);

  void WriteASTCore(Sema &SemaRef, MemorizeStatCalls *StatCalls,
                    const char* isysroot);
  void WriteASTChain(Sema &SemaRef, MemorizeStatCalls *StatCalls,
                     const char* isysroot);
  
public:
  /// \brief Create a new precompiled header writer that outputs to
  /// the given bitstream.
  ASTWriter(llvm::BitstreamWriter &Stream);

  /// \brief Write a precompiled header for the given semantic analysis.
  ///
  /// \param SemaRef a reference to the semantic analysis object that processed
  /// the AST to be written into the precompiled header.
  ///
  /// \param StatCalls the object that cached all of the stat() calls made while
  /// searching for source files and headers.
  ///
  /// \param isysroot if non-NULL, write a relocatable PCH file whose headers
  /// are relative to the given system root.
  ///
  /// \param PPRec Record of the preprocessing actions that occurred while
  /// preprocessing this file, e.g., macro instantiations
  void WriteAST(Sema &SemaRef, MemorizeStatCalls *StatCalls,
                const char* isysroot);

  /// \brief Emit a source location.
  void AddSourceLocation(SourceLocation Loc, RecordData &Record);

  /// \brief Emit a source range.
  void AddSourceRange(SourceRange Range, RecordData &Record);
  
  /// \brief Emit an integral value.
  void AddAPInt(const llvm::APInt &Value, RecordData &Record);

  /// \brief Emit a signed integral value.
  void AddAPSInt(const llvm::APSInt &Value, RecordData &Record);

  /// \brief Emit a floating-point value.
  void AddAPFloat(const llvm::APFloat &Value, RecordData &Record);

  /// \brief Emit a reference to an identifier.
  void AddIdentifierRef(const IdentifierInfo *II, RecordData &Record);

  /// \brief Emit a Selector (which is a smart pointer reference).
  void AddSelectorRef(Selector, RecordData &Record);

  /// \brief Emit a CXXTemporary.
  void AddCXXTemporary(const CXXTemporary *Temp, RecordData &Record);

  /// \brief Get the unique number used to refer to the given selector.
  serialization::SelectorID getSelectorRef(Selector Sel);
  
  /// \brief Get the unique number used to refer to the given identifier.
  serialization::IdentID getIdentifierRef(const IdentifierInfo *II);

  /// \brief Retrieve the offset of the macro definition for the given
  /// identifier.
  ///
  /// The identifier must refer to a macro.
  uint64_t getMacroOffset(const IdentifierInfo *II) {
    assert(MacroOffsets.find(II) != MacroOffsets.end() &&
           "Identifier does not name a macro");
    return MacroOffsets[II];
  }

  /// \brief Retrieve the ID number corresponding to the given macro 
  /// definition.
  serialization::IdentID getMacroDefinitionID(MacroDefinition *MD);
  
  /// \brief Emit a reference to a type.
  void AddTypeRef(QualType T, RecordData &Record);

  /// \brief Force a type to be emitted and get its ID.
  serialization::TypeID GetOrCreateTypeID(QualType T);

  /// \brief Determine the type ID of an already-emitted type.
  serialization::TypeID getTypeID(QualType T) const;

  /// \brief Force a type to be emitted and get its index.
  serialization::TypeIdx GetOrCreateTypeIdx(QualType T);

  /// \brief Determine the type index of an already-emitted type.
  serialization::TypeIdx getTypeIdx(QualType T) const;

  /// \brief Emits a reference to a declarator info.
  void AddTypeSourceInfo(TypeSourceInfo *TInfo, RecordData &Record);

  /// \brief Emits a template argument location info.
  void AddTemplateArgumentLocInfo(TemplateArgument::ArgKind Kind,
                                  const TemplateArgumentLocInfo &Arg,
                                  RecordData &Record);

  /// \brief Emits a template argument location.
  void AddTemplateArgumentLoc(const TemplateArgumentLoc &Arg,
                              RecordData &Record);

  /// \brief Emit a reference to a declaration.
  void AddDeclRef(const Decl *D, RecordData &Record);

  /// \brief Force a declaration to be emitted and get its ID.
  serialization::DeclID GetDeclRef(const Decl *D);

  /// \brief Determine the declaration ID of an already-emitted
  /// declaration.
  serialization::DeclID getDeclID(const Decl *D);

  /// \brief Emit a declaration name.
  void AddDeclarationName(DeclarationName Name, RecordData &Record);

  /// \brief Emit a nested name specifier.
  void AddNestedNameSpecifier(NestedNameSpecifier *NNS, RecordData &Record);
  
  /// \brief Emit a template name.
  void AddTemplateName(TemplateName Name, RecordData &Record);

  /// \brief Emit a template argument.
  void AddTemplateArgument(const TemplateArgument &Arg, RecordData &Record);

  /// \brief Emit a template parameter list.
  void AddTemplateParameterList(const TemplateParameterList *TemplateParams,
                                RecordData &Record);

  /// \brief Emit a template argument list.
  void AddTemplateArgumentList(const TemplateArgumentList *TemplateArgs,
                                RecordData &Record);

  /// \brief Emit a UnresolvedSet structure.
  void AddUnresolvedSet(const UnresolvedSetImpl &Set, RecordData &Record);

  /// \brief Emit a C++ base specifier.
  void AddCXXBaseSpecifier(const CXXBaseSpecifier &Base, RecordData &Record);

  /// \brief Emit a CXXBaseOrMemberInitializer array.
  void AddCXXBaseOrMemberInitializers(
                        const CXXBaseOrMemberInitializer * const *BaseOrMembers,
                        unsigned NumBaseOrMembers, RecordData &Record);

  /// \brief Add a string to the given record.
  void AddString(llvm::StringRef Str, RecordData &Record);

  /// \brief Mark a namespace as needing an update.
  void AddUpdatedNamespace(const NamespaceDecl *NS) {
    UpdatedNamespaces.insert(NS);
  }

  /// \brief Record a template specialization or partial specialization of
  /// a template from a previous PCH file.
  void AddAdditionalTemplateSpecialization(serialization::DeclID Templ,
                                           serialization::DeclID Spec) {
    AdditionalTemplateSpecializations[Templ].push_back(Spec);
  }

  /// \brief Note that the identifier II occurs at the given offset
  /// within the identifier table.
  void SetIdentifierOffset(const IdentifierInfo *II, uint32_t Offset);

  /// \brief Note that the selector Sel occurs at the given offset
  /// within the method pool/selector table.
  void SetSelectorOffset(Selector Sel, uint32_t Offset);

  /// \brief Add the given statement or expression to the queue of
  /// statements to emit.
  ///
  /// This routine should be used when emitting types and declarations
  /// that have expressions as part of their formulation. Once the
  /// type or declaration has been written, call FlushStmts() to write
  /// the corresponding statements just after the type or
  /// declaration.
  void AddStmt(Stmt *S) {
      CollectedStmts->push_back(S);
  }

  /// \brief Flush all of the statements and expressions that have
  /// been added to the queue via AddStmt().
  void FlushStmts();

  /// \brief Record an ID for the given switch-case statement.
  unsigned RecordSwitchCaseID(SwitchCase *S);

  /// \brief Retrieve the ID for the given switch-case statement.
  unsigned getSwitchCaseID(SwitchCase *S);

  /// \brief Retrieve the ID for the given label statement, which may
  /// or may not have been emitted yet.
  unsigned GetLabelID(LabelStmt *S);

  unsigned getParmVarDeclAbbrev() const { return ParmVarDeclAbbrev; }

  bool hasChain() const { return Chain; }

  // ASTDeserializationListener implementation
  void SetReader(ASTReader *Reader);
  void IdentifierRead(serialization::IdentID ID, IdentifierInfo *II);
  void TypeRead(serialization::TypeIdx Idx, QualType T);
  void DeclRead(serialization::DeclID ID, const Decl *D);
  void SelectorRead(serialization::SelectorID iD, Selector Sel);
};

/// \brief AST and semantic-analysis consumer that generates a
/// precompiled header from the parsed source code.
class PCHGenerator : public SemaConsumer {
  const Preprocessor &PP;
  const char *isysroot;
  llvm::raw_ostream *Out;
  Sema *SemaPtr;
  MemorizeStatCalls *StatCalls; // owned by the FileManager
  std::vector<unsigned char> Buffer;
  llvm::BitstreamWriter Stream;
  ASTWriter Writer;

protected:
  ASTWriter &getWriter() { return Writer; }
  const ASTWriter &getWriter() const { return Writer; }

public:
  PCHGenerator(const Preprocessor &PP, bool Chaining,
               const char *isysroot, llvm::raw_ostream *Out);
  virtual void InitializeSema(Sema &S) { SemaPtr = &S; }
  virtual void HandleTranslationUnit(ASTContext &Ctx);
  virtual ASTDeserializationListener *GetASTDeserializationListener();
};

} // end namespace clang

#endif