text: //===--- Module.h - Describe a module ---------------------------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  ///
  /// \file
  /// \brief Defines the clang::Module class, which describes a module in the
  /// source code.
  ///
  //===----------------------------------------------------------------------===//
  #ifndef LLVM_CLANG_BASIC_MODULE_H
  #define LLVM_CLANG_BASIC_MODULE_H
  
  #include "clang/Basic/SourceLocation.h"
  #include "llvm/ADT/PointerIntPair.h"
  #include "llvm/ADT/PointerUnion.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/ADT/StringMap.h"
  #include "llvm/ADT/StringRef.h"
  #include <string>
  #include <utility>
  #include <vector>
  
  namespace llvm {
    class raw_ostream;
  }
  
  namespace clang {
    
  class DirectoryEntry;
  class FileEntry;
  class LangOptions;
  class TargetInfo;
    
  /// \brief Describes the name of a module.
  typedef llvm::SmallVector<std::pair<std::string, SourceLocation>, 2>
    ModuleId;
    
  /// \brief Describes a module or submodule.
  class Module {
  public:
    /// \brief The name of this module.
    std::string Name;
    
    /// \brief The location of the module definition.
    SourceLocation DefinitionLoc;
    
    /// \brief The parent of this module. This will be NULL for the top-level
    /// module.
    Module *Parent;
    
    /// \brief The umbrella header or directory.
    llvm::PointerUnion<const DirectoryEntry *, const FileEntry *> Umbrella;
    
  private:
    /// \brief The submodules of this module, indexed by name.
    std::vector<Module *> SubModules;
    
    /// \brief A mapping from the submodule name to the index into the 
    /// \c SubModules vector at which that submodule resides.
    llvm::StringMap<unsigned> SubModuleIndex;
  
    /// \brief The AST file if this is a top-level module which has a
    /// corresponding serialized AST file, or null otherwise.
    const FileEntry *ASTFile;
    
  public:
    /// \brief The headers that are part of this module.
    llvm::SmallVector<const FileEntry *, 2> Headers;
  
    /// \brief The set of language features required to use this module.
    ///
    /// If any of these features is not present, the \c IsAvailable bit
    /// will be false to indicate that this (sub)module is not
    /// available.
    llvm::SmallVector<std::string, 2> Requires;
  
    /// \brief Whether this module is available in the current
    /// translation unit.
    unsigned IsAvailable : 1;
  
    /// \brief Whether this module was loaded from a module file.
    unsigned IsFromModuleFile : 1;
    
    /// \brief Whether this is a framework module.
    unsigned IsFramework : 1;
    
    /// \brief Whether this is an explicit submodule.
    unsigned IsExplicit : 1;
    
    /// \brief Whether this is a "system" module (which assumes that all
    /// headers in it are system headers).
    unsigned IsSystem : 1;
    
    /// \brief Whether we should infer submodules for this module based on 
    /// the headers.
    ///
    /// Submodules can only be inferred for modules with an umbrella header.
    unsigned InferSubmodules : 1;
    
    /// \brief Whether, when inferring submodules, the inferred submodules
    /// should be explicit.
    unsigned InferExplicitSubmodules : 1;
    
    /// \brief Whether, when inferring submodules, the inferr submodules should
    /// export all modules they import (e.g., the equivalent of "export *").
    unsigned InferExportWildcard : 1;
    
    /// \brief Describes the visibility of the various names within a
    /// particular module.
    enum NameVisibilityKind {
      /// \brief All of the names in this module are hidden.
      ///
      Hidden,
      /// \brief Only the macro names in this module are visible.
      MacrosVisible,
      /// \brief All of the names in this module are visible.
      AllVisible
    };  
    
    ///\ brief The visibility of names within this particular module.
    NameVisibilityKind NameVisibility;
  
    /// \brief The location of the inferred submodule.
    SourceLocation InferredSubmoduleLoc;
  
    /// \brief The set of modules imported by this module, and on which this
    /// module depends.
    llvm::SmallVector<Module *, 2> Imports;
    
    /// \brief Describes an exported module.
    ///
    /// The pointer is the module being re-exported, while the bit will be true
    /// to indicate that this is a wildcard export.
    typedef llvm::PointerIntPair<Module *, 1, bool> ExportDecl;
    
    /// \brief The set of export declarations.
    llvm::SmallVector<ExportDecl, 2> Exports;
    
    /// \brief Describes an exported module that has not yet been resolved
    /// (perhaps because the module it refers to has not yet been loaded).
    struct UnresolvedExportDecl {
      /// \brief The location of the 'export' keyword in the module map file.
      SourceLocation ExportLoc;
      
      /// \brief The name of the module.
      ModuleId Id;
      
      /// \brief Whether this export declaration ends in a wildcard, indicating
      /// that all of its submodules should be exported (rather than the named
      /// module itself).
      bool Wildcard;
    };
    
    /// \brief The set of export declarations that have yet to be resolved.
    llvm::SmallVector<UnresolvedExportDecl, 2> UnresolvedExports;
    
    /// \brief Construct a top-level module.
    explicit Module(StringRef Name, SourceLocation DefinitionLoc,
                    bool IsFramework)
      : Name(Name), DefinitionLoc(DefinitionLoc), Parent(0),Umbrella(),ASTFile(0),
        IsAvailable(true), IsFromModuleFile(false), IsFramework(IsFramework), 
        IsExplicit(false), IsSystem(false),
        InferSubmodules(false), InferExplicitSubmodules(false),
        InferExportWildcard(false), NameVisibility(Hidden) { }
    
    /// \brief Construct a new module or submodule.
    Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent, 
           bool IsFramework, bool IsExplicit);
    
    ~Module();
    
    /// \brief Determine whether this module is available for use within the
    /// current translation unit.
    bool isAvailable() const { return IsAvailable; }
  
    /// \brief Determine whether this module is available for use within the
    /// current translation unit.
    ///
    /// \param LangOpts The language options used for the current
    /// translation unit.
    ///
    /// \param Target The target options used for the current translation unit.
    ///
    /// \param Feature If this module is unavailable, this parameter
    /// will be set to one of the features that is required for use of
    /// this module (but is not available).
    bool isAvailable(const LangOptions &LangOpts, 
                     const TargetInfo &Target,
                     StringRef &Feature) const;
  
    /// \brief Determine whether this module is a submodule.
    bool isSubModule() const { return Parent != 0; }
    
    /// \brief Determine whether this module is a submodule of the given other
    /// module.
    bool isSubModuleOf(Module *Other) const;
    
    /// \brief Determine whether this module is a part of a framework,
    /// either because it is a framework module or because it is a submodule
    /// of a framework module.
    bool isPartOfFramework() const {
      for (const Module *Mod = this; Mod; Mod = Mod->Parent) 
        if (Mod->IsFramework)
          return true;
      
      return false;
    }
    
    /// \brief Retrieve the full name of this module, including the path from
    /// its top-level module.
    std::string getFullModuleName() const;
  
    /// \brief Retrieve the top-level module for this (sub)module, which may
    /// be this module.
    Module *getTopLevelModule() {
      return const_cast<Module *>(
               const_cast<const Module *>(this)->getTopLevelModule());
    }
  
    /// \brief Retrieve the top-level module for this (sub)module, which may
    /// be this module.
    const Module *getTopLevelModule() const;
    
    /// \brief Retrieve the name of the top-level module.
    ///
    StringRef getTopLevelModuleName() const {
      return getTopLevelModule()->Name;
    }
  
    /// \brief The serialized AST file for this module, if one was created.
    const FileEntry *getASTFile() const {
      return getTopLevelModule()->ASTFile;
    }
  
    /// \brief Set the serialized AST file for the top-level module of this module.
    void setASTFile(const FileEntry *File) {
      assert((getASTFile() == 0 || getASTFile() == File) && "file path changed");
      getTopLevelModule()->ASTFile = File;
    }
  
    /// \brief Retrieve the directory for which this module serves as the
    /// umbrella.
    const DirectoryEntry *getUmbrellaDir() const;
  
    /// \brief Retrieve the header that serves as the umbrella header for this
    /// module.
    const FileEntry *getUmbrellaHeader() const {
      return Umbrella.dyn_cast<const FileEntry *>();
    }
  
    /// \brief Determine whether this module has an umbrella directory that is
    /// not based on an umbrella header.
    bool hasUmbrellaDir() const {
      return Umbrella && Umbrella.is<const DirectoryEntry *>();
    }
  
    /// \brief Add the given feature requirement to the list of features
    /// required by this module.
    ///
    /// \param Feature The feature that is required by this module (and
    /// its submodules).
    ///
    /// \param LangOpts The set of language options that will be used to
    /// evaluate the availability of this feature.
    ///
    /// \param Target The target options that will be used to evaluate the
    /// availability of this feature.
    void addRequirement(StringRef Feature, const LangOptions &LangOpts,
                        const TargetInfo &Target);
  
    /// \brief Find the submodule with the given name.
    ///
    /// \returns The submodule if found, or NULL otherwise.
    Module *findSubmodule(StringRef Name) const;
    
    typedef std::vector<Module *>::iterator submodule_iterator;
    typedef std::vector<Module *>::const_iterator submodule_const_iterator;
    
    submodule_iterator submodule_begin() { return SubModules.begin(); }
    submodule_const_iterator submodule_begin() const {return SubModules.begin();}
    submodule_iterator submodule_end()   { return SubModules.end(); }
    submodule_const_iterator submodule_end() const { return SubModules.end(); }
    
    /// \brief Print the module map for this module to the given stream. 
    ///
    void print(llvm::raw_ostream &OS, unsigned Indent = 0) const;
    
    /// \brief Dump the contents of this module to the given output stream.
    void dump() const;
  };
  
  } // end namespace clang
  
  
  #endif // LLVM_CLANG_BASIC_MODULE_H
  