path: root/include/clang/Lex/HeaderSearch.h

//===--- HeaderSearch.h - Resolve Header File Locations ---------*- 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 HeaderSearch interface.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LEX_HEADERSEARCH_H
#define LLVM_CLANG_LEX_HEADERSEARCH_H

#include "clang/Lex/DirectoryLookup.h"
#include "clang/Lex/ModuleMap.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/Allocator.h"
#include <vector>

namespace clang {
  
class DiagnosticsEngine;  
class ExternalIdentifierLookup;
class FileEntry;
class FileManager;
class HeaderSearchOptions;
class IdentifierInfo;

/// \brief The preprocessor keeps track of this information for each
/// file that is \#included.
struct HeaderFileInfo {
  /// \brief True if this is a \#import'd or \#pragma once file.
  unsigned isImport : 1;

  /// \brief True if this is a \#pragma once file.
  unsigned isPragmaOnce : 1;

  /// DirInfo - Keep track of whether this is a system header, and if so,
  /// whether it is C++ clean or not.  This can be set by the include paths or
  /// by \#pragma gcc system_header.  This is an instance of
  /// SrcMgr::CharacteristicKind.
  unsigned DirInfo : 2;

  /// \brief Whether this header file info was supplied by an external source.
  unsigned External : 1;

  /// \brief Whether this header is part of a module.
  unsigned isModuleHeader : 1;
  
  /// \brief Whether this structure is considered to already have been
  /// "resolved", meaning that it was loaded from the external source.
  unsigned Resolved : 1;
  
  /// \brief Whether this is a header inside a framework that is currently
  /// being built. 
  ///
  /// When a framework is being built, the headers have not yet been placed
  /// into the appropriate framework subdirectories, and therefore are
  /// provided via a header map. This bit indicates when this is one of
  /// those framework headers.
  unsigned IndexHeaderMapHeader : 1;
  
  /// \brief The number of times the file has been included already.
  unsigned short NumIncludes;

  /// \brief The ID number of the controlling macro.
  ///
  /// This ID number will be non-zero when there is a controlling
  /// macro whose IdentifierInfo may not yet have been loaded from
  /// external storage.
  unsigned ControllingMacroID;

  /// If this file has a \#ifndef XXX (or equivalent) guard that
  /// protects the entire contents of the file, this is the identifier
  /// for the macro that controls whether or not it has any effect.
  ///
  /// Note: Most clients should use getControllingMacro() to access
  /// the controlling macro of this header, since
  /// getControllingMacro() is able to load a controlling macro from
  /// external storage.
  const IdentifierInfo *ControllingMacro;

  /// \brief If this header came from a framework include, this is the name
  /// of the framework.
  StringRef Framework;
  
  HeaderFileInfo()
    : isImport(false), isPragmaOnce(false), DirInfo(SrcMgr::C_User), 
      External(false), isModuleHeader(false), Resolved(false),
      IndexHeaderMapHeader(false),
      NumIncludes(0), ControllingMacroID(0), ControllingMacro(0)  {}

  /// \brief Retrieve the controlling macro for this header file, if
  /// any.
  const IdentifierInfo *getControllingMacro(ExternalIdentifierLookup *External);
  
  /// \brief Determine whether this is a non-default header file info, e.g.,
  /// it corresponds to an actual header we've included or tried to include.
  bool isNonDefault() const {
    return isImport || isPragmaOnce || NumIncludes || ControllingMacro || 
      ControllingMacroID;
  }
};

/// \brief An external source of header file information, which may supply
/// information about header files already included.
class ExternalHeaderFileInfoSource {
public:
  virtual ~ExternalHeaderFileInfoSource();
  
  /// \brief Retrieve the header file information for the given file entry.
  ///
  /// \returns Header file information for the given file entry, with the
  /// \c External bit set. If the file entry is not known, return a 
  /// default-constructed \c HeaderFileInfo.
  virtual HeaderFileInfo GetHeaderFileInfo(const FileEntry *FE) = 0;
};
  
/// \brief Encapsulates the information needed to find the file referenced
/// by a \#include or \#include_next, (sub-)framework lookup, etc.
class HeaderSearch {
  /// This structure is used to record entries in our framework cache.
  struct FrameworkCacheEntry {
    /// The directory entry which should be used for the cached framework.
    const DirectoryEntry *Directory;

    /// Whether this framework has been "user-specified" to be treated as if it
    /// were a system framework (even if it was found outside a system framework
    /// directory).
    bool IsUserSpecifiedSystemFramework;
  };

  /// \brief Header-search options used to initialize this header search.
  IntrusiveRefCntPtr<HeaderSearchOptions> HSOpts;

  FileManager &FileMgr;
  /// \#include search path information.  Requests for \#include "x" search the
  /// directory of the \#including file first, then each directory in SearchDirs
  /// consecutively. Requests for <x> search the current dir first, then each
  /// directory in SearchDirs, starting at AngledDirIdx, consecutively.  If
  /// NoCurDirSearch is true, then the check for the file in the current
  /// directory is suppressed.
  std::vector<DirectoryLookup> SearchDirs;
  unsigned AngledDirIdx;
  unsigned SystemDirIdx;
  bool NoCurDirSearch;

  /// \brief \#include prefixes for which the 'system header' property is
  /// overridden.
  ///
  /// For a \#include "x" or \#include \<x> directive, the last string in this
  /// list which is a prefix of 'x' determines whether the file is treated as
  /// a system header.
  std::vector<std::pair<std::string, bool> > SystemHeaderPrefixes;

  /// \brief The path to the module cache.
  std::string ModuleCachePath;
  
  /// \brief All of the preprocessor-specific data about files that are
  /// included, indexed by the FileEntry's UID.
  std::vector<HeaderFileInfo> FileInfo;

  /// \brief Keeps track of each lookup performed by LookupFile.
  ///
  /// The first part of the value is the starting index in SearchDirs
  /// that the cached search was performed from.  If there is a hit and
  /// this value doesn't match the current query, the cache has to be
  /// ignored.  The second value is the entry in SearchDirs that satisfied
  /// the query.
  llvm::StringMap<std::pair<unsigned, unsigned>, llvm::BumpPtrAllocator>
    LookupFileCache;

  /// \brief Collection mapping a framework or subframework
  /// name like "Carbon" to the Carbon.framework directory.
  llvm::StringMap<FrameworkCacheEntry, llvm::BumpPtrAllocator> FrameworkMap;

  /// IncludeAliases - maps include file names (including the quotes or
  /// angle brackets) to other include file names.  This is used to support the
  /// include_alias pragma for Microsoft compatibility.
  typedef llvm::StringMap<std::string, llvm::BumpPtrAllocator>
    IncludeAliasMap;
  OwningPtr<IncludeAliasMap> IncludeAliases;

  /// HeaderMaps - This is a mapping from FileEntry -> HeaderMap, uniquing
  /// headermaps.  This vector owns the headermap.
  std::vector<std::pair<const FileEntry*, const HeaderMap*> > HeaderMaps;

  /// \brief The mapping between modules and headers.
  mutable ModuleMap ModMap;
  
  /// \brief Describes whether a given directory has a module map in it.
  llvm::DenseMap<const DirectoryEntry *, bool> DirectoryHasModuleMap;
  
  /// \brief Uniqued set of framework names, which is used to track which 
  /// headers were included as framework headers.
  llvm::StringSet<llvm::BumpPtrAllocator> FrameworkNames;
  
  /// \brief Entity used to resolve the identifier IDs of controlling
  /// macros into IdentifierInfo pointers, as needed.
  ExternalIdentifierLookup *ExternalLookup;

  /// \brief Entity used to look up stored header file information.
  ExternalHeaderFileInfoSource *ExternalSource;
  
  // Various statistics we track for performance analysis.
  unsigned NumIncluded;
  unsigned NumMultiIncludeFileOptzn;
  unsigned NumFrameworkLookups, NumSubFrameworkLookups;

  // HeaderSearch doesn't support default or copy construction.
  HeaderSearch(const HeaderSearch&) LLVM_DELETED_FUNCTION;
  void operator=(const HeaderSearch&) LLVM_DELETED_FUNCTION;

  friend class DirectoryLookup;
  
public:
  HeaderSearch(IntrusiveRefCntPtr<HeaderSearchOptions> HSOpts,
               FileManager &FM, DiagnosticsEngine &Diags,
               const LangOptions &LangOpts, const TargetInfo *Target);
  ~HeaderSearch();

  /// \brief Retrieve the header-search options with which this header search
  /// was initialized.
  HeaderSearchOptions &getHeaderSearchOpts() const { return *HSOpts; }
  
  FileManager &getFileMgr() const { return FileMgr; }

  /// \brief Interface for setting the file search paths.
  void SetSearchPaths(const std::vector<DirectoryLookup> &dirs,
                      unsigned angledDirIdx, unsigned systemDirIdx,
                      bool noCurDirSearch) {
    assert(angledDirIdx <= systemDirIdx && systemDirIdx <= dirs.size() &&
        "Directory indicies are unordered");
    SearchDirs = dirs;
    AngledDirIdx = angledDirIdx;
    SystemDirIdx = systemDirIdx;
    NoCurDirSearch = noCurDirSearch;
    //LookupFileCache.clear();
  }

  /// \brief Add an additional search path.
  void AddSearchPath(const DirectoryLookup &dir, bool isAngled) {
    unsigned idx = isAngled ? SystemDirIdx : AngledDirIdx;
    SearchDirs.insert(SearchDirs.begin() + idx, dir);
    if (!isAngled)
      AngledDirIdx++;
    SystemDirIdx++;
  }

  /// \brief Set the list of system header prefixes.
  void SetSystemHeaderPrefixes(ArrayRef<std::pair<std::string, bool> > P) {
    SystemHeaderPrefixes.assign(P.begin(), P.end());
  }

  /// \brief Checks whether the map exists or not.
  bool HasIncludeAliasMap() const {
    return IncludeAliases;
  }

  /// \brief Map the source include name to the dest include name.
  ///
  /// The Source should include the angle brackets or quotes, the dest 
  /// should not.  This allows for distinction between <> and "" headers.
  void AddIncludeAlias(