//===- HeaderSearch.h - Resolve Header File Locations -----------*- 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 file defines the HeaderSearch interface.
 
//
 
//===----------------------------------------------------------------------===//
 
 
 
#ifndef LLVM_CLANG_LEX_HEADERSEARCH_H
 
#define LLVM_CLANG_LEX_HEADERSEARCH_H
 
 
 
#include "clang/Basic/SourceLocation.h"
 
#include "clang/Basic/SourceManager.h"
 
#include "clang/Lex/DirectoryLookup.h"
 
#include "clang/Lex/HeaderMap.h"
 
#include "clang/Lex/ModuleMap.h"
 
#include "llvm/ADT/ArrayRef.h"
 
#include "llvm/ADT/DenseMap.h"
 
#include "llvm/ADT/SmallString.h"
 
#include "llvm/ADT/StringMap.h"
 
#include "llvm/ADT/StringRef.h"
 
#include "llvm/ADT/StringSet.h"
 
#include "llvm/Support/Allocator.h"
 
#include <cassert>
 
#include <cstddef>
 
#include <memory>
 
#include <string>
 
#include <utility>
 
#include <vector>
 
 
 
namespace llvm {
 
 
 
class Triple;
 
 
 
} // namespace llvm
 
 
 
namespace clang {
 
 
 
class DiagnosticsEngine;
 
class DirectoryEntry;
 
class ExternalPreprocessorSource;
 
class FileEntry;
 
class FileManager;
 
class HeaderSearch;
 
class HeaderSearchOptions;
 
class IdentifierInfo;
 
class LangOptions;
 
class Module;
 
class Preprocessor;
 
class TargetInfo;
 
 
 
/// The preprocessor keeps track of this information for each
 
/// file that is \#included.
 
struct HeaderFileInfo {
 
  // TODO: Whether the file was imported is not a property of the file itself.
 
  // It's a preprocessor state, move it there.
 
  /// True if this is a \#import'd file.
 
  unsigned isImport : 1;
 
 
 
  /// True if this is a \#pragma once file.
 
  unsigned isPragmaOnce : 1;
 
 
 
  /// 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 : 3;
 
 
 
  /// Whether this header file info was supplied by an external source,
 
  /// and has not changed since.
 
  unsigned External : 1;
 
 
 
  /// Whether this header is part of a module.
 
  unsigned isModuleHeader : 1;
 
 
 
  /// Whether this header is part of the module that we are building.
 
  unsigned isCompilingModuleHeader : 1;
 
 
 
  /// Whether this structure is considered to already have been
 
  /// "resolved", meaning that it was loaded from the external source.
 
  unsigned Resolved : 1;
 
 
 
  /// 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;
 
 
 
  /// Whether this file has been looked up as a header.
 
  unsigned IsValid : 1;
 
 
 
  /// 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 = 0;
 
 
 
  /// 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 = nullptr;
 
 
 
  /// 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), isCompilingModuleHeader(false),
 
        Resolved(false), IndexHeaderMapHeader(false), IsValid(false)  {}
 
 
 
  /// Retrieve the controlling macro for this header file, if
 
  /// any.
 
  const IdentifierInfo *
 
  getControllingMacro(ExternalPreprocessorSource *External);
 
};
 
 
 
/// An external source of header file information, which may supply
 
/// information about header files already included.
 
class ExternalHeaderFileInfoSource {
 
public:
 
  virtual ~ExternalHeaderFileInfoSource();
 
 
 
  /// 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;
 
};
 
 
 
/// This structure is used to record entries in our framework cache.
 
struct FrameworkCacheEntry {
 
  /// The directory entry which should be used for the cached framework.
 
  OptionalDirectoryEntryRef 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;
 
};
 
 
 
namespace detail {
 
template <bool Const, typename T>
 
using Qualified = std::conditional_t<Const, const T, T>;
 
 
 
/// Forward iterator over the search directories of \c HeaderSearch.
 
template <bool IsConst>
 
struct SearchDirIteratorImpl
 
    : llvm::iterator_facade_base<SearchDirIteratorImpl<IsConst>,
 
                                 std::forward_iterator_tag,
 
                                 Qualified<IsConst, DirectoryLookup>> {
 
  /// Const -> non-const iterator conversion.
 
  template <typename Enable = std::enable_if<IsConst, bool>>
 
  SearchDirIteratorImpl(const SearchDirIteratorImpl<false> &Other)
 
      : HS(Other.HS), Idx(Other.Idx) {}
 
 
 
  SearchDirIteratorImpl(const SearchDirIteratorImpl &) = default;
 
 
 
  SearchDirIteratorImpl &operator=(const SearchDirIteratorImpl &) = default;
 
 
 
  bool operator==(const SearchDirIteratorImpl &RHS) const {
 
    return HS == RHS.HS && Idx == RHS.Idx;
 
  }
 
 
 
  SearchDirIteratorImpl &operator++() {
 
    assert(*this && "Invalid iterator.");
 
    ++Idx;
 
    return *this;
 
  }
 
 
 
  Qualified<IsConst, DirectoryLookup> &operator*() const {
 
    assert(*this && "Invalid iterator.");
 
    return HS->SearchDirs[Idx];
 
  }
 
 
 
  /// Creates an invalid iterator.
 
  SearchDirIteratorImpl(std::nullptr_t) : HS(nullptr), Idx(0) {}
 
 
 
  /// Checks whether the iterator is valid.
 
  explicit operator bool() const { return HS != nullptr; }
 
 
 
private:
 
  /// The parent \c HeaderSearch. This is \c nullptr for invalid iterator.
 
  Qualified<IsConst, HeaderSearch> *HS;
 
 
 
  /// The index of the current element.
 
  size_t Idx;
 
 
 
  /// The constructor that creates a valid iterator.
 
  SearchDirIteratorImpl(Qualified<IsConst, HeaderSearch> &HS, size_t Idx)
 
      : HS(&HS), Idx(Idx) {}
 
 
 
  /// Only HeaderSearch is allowed to instantiate valid iterators.
 
  friend HeaderSearch;
 
 
 
  /// Enables const -> non-const conversion.
 
  friend SearchDirIteratorImpl<!IsConst>;
 
};
 
} // namespace detail
 
 
 
using ConstSearchDirIterator = detail::SearchDirIteratorImpl<true>;
 
using SearchDirIterator = detail::SearchDirIteratorImpl<false>;
 
 
 
using ConstSearchDirRange = llvm::iterator_range<ConstSearchDirIterator>;
 
using SearchDirRange = llvm::iterator_range<SearchDirIterator>;
 
 
 
/// Encapsulates the information needed to find the file referenced
 
/// by a \#include or \#include_next, (sub-)framework lookup, etc.
 
class HeaderSearch {
 
  friend class DirectoryLookup;
 
 
 
  friend ConstSearchDirIterator;
 
  friend SearchDirIterator;
 
 
 
  /// Header-search options used to initialize this header search.
 
  std::shared_ptr<HeaderSearchOptions> HSOpts;
 
 
 
  /// Mapping from SearchDir to HeaderSearchOptions::UserEntries indices.
 
  llvm::DenseMap<unsigned, unsigned> SearchDirToHSEntry;
 
 
 
  DiagnosticsEngine &Diags;
 
  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;
 
  /// Whether the DirectoryLookup at the corresponding index in SearchDirs has
 
  /// been successfully used to lookup a file.
 
  std::vector<bool> SearchDirsUsage;
 
  unsigned AngledDirIdx = 0;
 
  unsigned SystemDirIdx = 0;
 
  bool NoCurDirSearch = false;
 
 
 
  /// Maps HeaderMap keys to SearchDir indices. When HeaderMaps are used
 
  /// heavily, SearchDirs can start with thousands of HeaderMaps, so this Index
 
  /// lets us avoid scanning them all to find a match.
 
  llvm::StringMap<unsigned, llvm::BumpPtrAllocator> SearchDirHeaderMapIndex;
 
 
 
  /// The index of the first SearchDir that isn't a header map.
 
  unsigned FirstNonHeaderMapSearchDirIdx = 0;
 
 
 
  /// \#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;
 
 
 
  /// The hash used for module cache paths.
 
  std::string ModuleHash;
 
 
 
  /// The path to the module cache.
 
  std::string ModuleCachePath;
 
 
 
  /// All of the preprocessor-specific data about files that are
 
  /// included, indexed by the FileEntry's UID.
 
  mutable std::vector<HeaderFileInfo> FileInfo;
 
 
 
  /// Keeps track of each lookup performed by LookupFile.
 
  struct LookupFileCacheInfo {
 
    /// Starting search directory iterator 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.
 
    ConstSearchDirIterator StartIt = nullptr;
 
 
 
    /// The search directory iterator that satisfied the query.
 
    ConstSearchDirIterator HitIt = nullptr;
 
 
 
    /// This is non-null if the original filename was mapped to a framework
 
    /// include via a headermap.
 
    const char *MappedName = nullptr;
 
 
 
    /// Default constructor -- Initialize all members with zero.
 
    LookupFileCacheInfo() = default;
 
 
 
    void reset(ConstSearchDirIterator NewStartIt) {
 
      StartIt = NewStartIt;
 
      MappedName = nullptr;
 
    }
 
  };
 
  llvm::StringMap<LookupFileCacheInfo, llvm::BumpPtrAllocator> LookupFileCache;
 
 
 
  /// Collection mapping a framework or subframework
 
  /// name like "Carbon" to the Carbon.framework directory.
 
  llvm::StringMap<FrameworkCacheEntry, llvm::BumpPtrAllocator> FrameworkMap;
 
 
 
  /// 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.
 
  using IncludeAliasMap =
 
      llvm::StringMap<std::string, llvm::BumpPtrAllocator>;
 
  std::unique_ptr<IncludeAliasMap> IncludeAliases;
 
 
 
  /// This is a mapping from FileEntry -> HeaderMap, uniquing headermaps.
 
  std::vector<std::pair<const FileEntry *, std::unique_ptr<HeaderMap>>> HeaderMaps;
 
 
 
  /// The mapping between modules and headers.
 
  mutable ModuleMap ModMap;
 
 
 
  /// Describes whether a given directory has a module map in it.
 
  llvm::DenseMap<const DirectoryEntry *, bool> DirectoryHasModuleMap;
 
 
 
  /// Set of module map files we've already loaded, and a flag indicating
 
  /// whether they were valid or not.
 
  llvm::DenseMap<const FileEntry *, bool> LoadedModuleMaps;
 
 
 
  // A map of discovered headers with their associated include file name.
 
  llvm::DenseMap<const FileEntry *, llvm::SmallString<64>> IncludeNames;
 
 
 
  /// Uniqued set of framework names, which is used to track which
 
  /// headers were included as framework headers.
 
  llvm::StringSet<llvm::BumpPtrAllocator> FrameworkNames;
 
 
 
  /// Entity used to resolve the identifier IDs of controlling
 
  /// macros into IdentifierInfo pointers, and keep the identifire up to date,
 
  /// as needed.
 
  ExternalPreprocessorSource *ExternalLookup = nullptr;
 
 
 
  /// Entity used to look up stored header file information.
 
  ExternalHeaderFileInfoSource *ExternalSource = nullptr;
 
 
 
  /// Scan all of the header maps at the beginning of SearchDirs and
 
  /// map their keys to the SearchDir index of their header map.
 
  void indexInitialHeaderMaps();
 
 
 
public:
 
  HeaderSearch(std::shared_ptr<HeaderSearchOptions> HSOpts,
 
               SourceManager &SourceMgr, DiagnosticsEngine &Diags,
 
               const LangOptions &LangOpts, const TargetInfo *Target);
 
  HeaderSearch(const HeaderSearch &) = delete;
 
  HeaderSearch &operator=(const HeaderSearch &) = delete;
 
 
 
  /// Retrieve the header-search options with which this header search
 
  /// was initialized.
 
  HeaderSearchOptions &getHeaderSearchOpts() const { return *HSOpts; }
 
 
 
  FileManager &getFileMgr() const { return FileMgr; }
 
 
 
  DiagnosticsEngine &getDiags() const { return Diags; }
 
 
 
  /// Interface for setting the file search paths.
 
  void SetSearchPaths(std::vector<DirectoryLookup> dirs, unsigned angledDirIdx,
 
                      unsigned systemDirIdx, bool noCurDirSearch,
 
                      llvm::DenseMap<unsigned, unsigned> searchDirToHSEntry);
 
 
 
  /// Add an additional search path.
 
  void AddSearchPath(const DirectoryLookup &dir, bool isAngled);
 
 
 
  /// Add an additional system search path.
 
  void AddSystemSearchPath(const DirectoryLookup &dir) {
 
    SearchDirs.push_back(dir);
 
    SearchDirsUsage.push_back(false);
 
  }
 
 
 
  /// Set the list of system header prefixes.
 
  void SetSystemHeaderPrefixes(ArrayRef<std::pair<std::string, bool>> P) {
 
    SystemHeaderPrefixes.assign(P.begin(), P.end());
 
  }
 
 
 
  /// Checks whether the map exists or not.
 
  bool HasIncludeAliasMap() const { return (bool)IncludeAliases; }
 
 
 
  /// 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(StringRef Source, StringRef Dest) {
 
    if (!IncludeAliases)
 
      IncludeAliases.reset(new IncludeAliasMap);
 
    (*IncludeAliases)[Source] = std::string(Dest);
 
  }
 
 
 
  /// Maps one header file name to a different header
 
  /// file name, for use with the include_alias pragma.  Note that the source
 
  /// file name should include the angle brackets or quotes.  Returns StringRef
 
  /// as null if the header cannot be mapped.
 
  StringRef MapHeaderToIncludeAlias(StringRef Source) {
 
    assert(IncludeAliases && "Trying to map headers when there's no map");
 
 
 
    // Do any filename replacements before anything else
 
    IncludeAliasMap::const_iterator Iter = IncludeAliases->find(Source);
 
    if (Iter != IncludeAliases->end())
 
      return Iter->second;
 
    return {};
 
  }
 
 
 
  /// Set the hash to use for module cache paths.
 
  void setModuleHash(StringRef Hash) { ModuleHash = std::string(Hash); }
 
 
 
  /// Set the path to the module cache.
 
  void setModuleCachePath(StringRef CachePath) {
 
    ModuleCachePath = std::string(CachePath);
 
  }
 
 
 
  /// Retrieve the module hash.
 
  StringRef getModuleHash() const { return ModuleHash; }
 
 
 
  /// Retrieve the path to the module cache.
 
  StringRef getModuleCachePath() const { return ModuleCachePath; }
 
 
 
  /// Consider modules when including files from this directory.
 
  void setDirectoryHasModuleMap(const DirectoryEntry* Dir) {
 
    DirectoryHasModuleMap[Dir] = true;
 
  }
 
 
 
  /// Forget everything we know about headers so far.
 
  void ClearFileInfo() {
 
    FileInfo.clear();
 
  }
 
 
 
  void SetExternalLookup(ExternalPreprocessorSource *EPS) {
 
    ExternalLookup = EPS;
 
  }
 
 
 
  ExternalPreprocessorSource *getExternalLookup() const {
 
    return ExternalLookup;
 
  }
 
 
 
  /// Set the external source of header information.
 
  void SetExternalSource(ExternalHeaderFileInfoSource *ES) {
 
    ExternalSource = ES;
 
  }
 
 
 
  /// Set the target information for the header search, if not
 
  /// already known.
 
  void setTarget(const TargetInfo &Target);
 
 
 
  /// Given a "foo" or \<foo> reference, look up the indicated file,
 
  /// return null on failure.
 
  ///
 
  /// \returns If successful, this returns 'UsedDir', the DirectoryLookup member
 
  /// the file was found in, or null if not applicable.
 
  ///
 
  /// \param IncludeLoc Used for diagnostics if valid.
 
  ///
 
  /// \param isAngled indicates whether the file reference is a <> reference.
 
  ///
 
  /// \param CurDir If non-null, the file was found in the specified directory
 
  /// search location.  This is used to implement \#include_next.
 
  ///
 
  /// \param Includers Indicates where the \#including file(s) are, in case
 
  /// relative searches are needed. In reverse order of inclusion.
 
  ///
 
  /// \param SearchPath If non-null, will be set to the search path relative
 
  /// to which the file was found. If the include path is absolute, SearchPath
 
  /// will be set to an empty string.
 
  ///
 
  /// \param RelativePath If non-null, will be set to the path relative to
 
  /// SearchPath at which the file was found. This only differs from the
 
  /// Filename for framework includes.
 
  ///
 
  /// \param SuggestedModule If non-null, and the file found is semantically
 
  /// part of a known module, this will be set to the module that should
 
  /// be imported instead of preprocessing/parsing the file found.
 
  ///
 
  /// \param IsMapped If non-null, and the search involved header maps, set to
 
  /// true.
 
  ///
 
  /// \param IsFrameworkFound If non-null, will be set to true if a framework is
 
  /// found in any of searched SearchDirs. Will be set to false if a framework
 
  /// is found only through header maps. Doesn't guarantee the requested file is
 
  /// found.
 
  OptionalFileEntryRef LookupFile(
 
      StringRef Filename, SourceLocation IncludeLoc, bool isAngled,
 
      ConstSearchDirIterator FromDir, ConstSearchDirIterator *CurDir,
 
      ArrayRef<std::pair<const FileEntry *, const DirectoryEntry *>> Includers,
 
      SmallVectorImpl<char> *SearchPath, SmallVectorImpl<char> *RelativePath,
 
      Module *RequestingModule, ModuleMap::KnownHeader *SuggestedModule,
 
      bool *IsMapped, bool *IsFrameworkFound, bool SkipCache = false,
 
      bool BuildSystemModule = false, bool OpenFile = true,
 
      bool CacheFailures = true);
 
 
 
  /// Look up a subframework for the specified \#include file.
 
  ///
 
  /// For example, if \#include'ing <HIToolbox/HIToolbox.h> from
 
  /// within ".../Carbon.framework/Headers/Carbon.h", check to see if
 
  /// HIToolbox is a subframework within Carbon.framework.  If so, return
 
  /// the FileEntry for the designated file, otherwise return null.
 
  OptionalFileEntryRef LookupSubframeworkHeader(
 
      StringRef Filename, const FileEntry *ContextFileEnt,
 
      SmallVectorImpl<char> *SearchPath, SmallVectorImpl<char> *RelativePath,
 
      Module *RequestingModule, ModuleMap::KnownHeader *SuggestedModule);
 
 
 
  /// Look up the specified framework name in our framework cache.
 
  /// \returns The DirectoryEntry it is in if we know, null otherwise.
 
  FrameworkCacheEntry &LookupFrameworkCache(StringRef FWName) {
 
    return FrameworkMap[FWName];
 
  }
 
 
 
  /// Mark the specified file as a target of a \#include,
 
  /// \#include_next, or \#import directive.
 
  ///
 
  /// \return false if \#including the file will have no effect or true
 
  /// if we should include it.
 
  bool ShouldEnterIncludeFile(Preprocessor &PP, const FileEntry *File,
 
                              bool isImport, bool ModulesEnabled, Module *M,
 
                              bool &IsFirstIncludeOfFile);
 
 
 
  /// Return whether the specified file is a normal header,
 
  /// a system header, or a C++ friendly system header.
 
  SrcMgr::CharacteristicKind getFileDirFlavor(const FileEntry *File) {
 
    return (SrcMgr::CharacteristicKind)getFileInfo(File).DirInfo;
 
  }
 
 
 
  /// Mark the specified file as a "once only" file due to
 
  /// \#pragma once.
 
  void MarkFileIncludeOnce(const FileEntry *File) {
 
    HeaderFileInfo &FI = getFileInfo(File);
 
    FI.isPragmaOnce = true;
 
  }
 
 
 
  /// Mark the specified file as a system header, e.g. due to
 
  /// \#pragma GCC system_header.
 
  void MarkFileSystemHeader(const FileEntry *File) {
 
    getFileInfo(File).DirInfo = SrcMgr::C_System;
 
  }
 
 
 
  /// Mark the specified file as part of a module.
 
  void MarkFileModuleHeader(const FileEntry *FE,
 
                            ModuleMap::ModuleHeaderRole Role,
 
                            bool isCompilingModuleHeader);
 
 
 
  /// Mark the specified file as having a controlling macro.
 
  ///
 
  /// This is used by the multiple-include optimization to eliminate
 
  /// no-op \#includes.
 
  void SetFileControllingMacro(const FileEntry *File,
 
                               const IdentifierInfo *ControllingMacro) {
 
    getFileInfo(File).ControllingMacro = ControllingMacro;
 
  }
 
 
 
  /// Determine whether this file is intended to be safe from
 
  /// multiple inclusions, e.g., it has \#pragma once or a controlling
 
  /// macro.
 
  ///
 
  /// This routine does not consider the effect of \#import
 
  bool isFileMultipleIncludeGuarded(const FileEntry *File);
 
 
 
  /// Determine whether the given file is known to have ever been \#imported.
 
  bool hasFileBeenImported(const FileEntry *File) {
 
    const HeaderFileInfo *FI = getExistingFileInfo(File);
 
    return FI && FI->isImport;
 
  }
 
 
 
  /// Determine which HeaderSearchOptions::UserEntries have been successfully
 
  /// used so far and mark their index with 'true' in the resulting bit vector.
 
  /// Note: implicit module maps don't contribute to entry usage.
 
  std::vector<bool> computeUserEntryUsage() const;
 
 
 
  /// This method returns a HeaderMap for the specified
 
  /// FileEntry, uniquing them through the 'HeaderMaps' datastructure.
 
  const HeaderMap *CreateHeaderMap(const FileEntry *FE);
 
 
 
  /// Get filenames for all registered header maps.
 
  void getHeaderMapFileNames(SmallVectorImpl<std::string> &Names) const;
 
 
 
  /// Retrieve the name of the cached module file that should be used
 
  /// to load the given module.
 
  ///
 
  /// \param Module The module whose module file name will be returned.
 
  ///
 
  /// \returns The name of the module file that corresponds to this module,
 
  /// or an empty string if this module does not correspond to any module file.
 
  std::string getCachedModuleFileName(Module *Module);
 
 
 
  /// Retrieve the name of the prebuilt module file that should be used
 
  /// to load a module with the given name.
 
  ///
 
  /// \param ModuleName The module whose module file name will be returned.
 
  ///
 
  /// \param FileMapOnly If true, then only look in the explicit module name
 
  //  to file name map and skip the directory search.
 
  ///
 
  /// \returns The name of the module file that corresponds to this module,
 
  /// or an empty string if this module does not correspond to any module file.
 
  std::string getPrebuiltModuleFileName(StringRef ModuleName,
 
                                        bool FileMapOnly = false);
 
 
 
  /// Retrieve the name of the prebuilt module file that should be used
 
  /// to load the given module.
 
  ///
 
  /// \param Module The module whose module file name will be returned.
 
  ///
 
  /// \returns The name of the module file that corresponds to this module,
 
  /// or an empty string if this module does not correspond to any module file.
 
  std::string getPrebuiltImplicitModuleFileName(Module *Module);
 
 
 
  /// Retrieve the name of the (to-be-)cached module file that should
 
  /// be used to load a module with the given name.
 
  ///
 
  /// \param ModuleName The module whose module file name will be returned.
 
  ///
 
  /// \param ModuleMapPath A path that when combined with \c ModuleName
 
  /// uniquely identifies this module. See Module::ModuleMap.
 
  ///
 
  /// \returns The name of the module file that corresponds to this module,
 
  /// or an empty string if this module does not correspond to any module file.
 
  std::string getCachedModuleFileName(StringRef ModuleName,
 
                                      StringRef ModuleMapPath);
 
 
 
  /// Lookup a module Search for a module with the given name.
 
  ///
 
  /// \param ModuleName The name of the module we're looking for.
 
  ///
 
  /// \param ImportLoc Location of the module include/import.
 
  ///
 
  /// \param AllowSearch Whether we are allowed to search in the various
 
  /// search directories to produce a module definition. If not, this lookup
 
  /// will only return an already-known module.
 
  ///
 
  /// \param AllowExtraModuleMapSearch Whether we allow to search modulemaps
 
  /// in subdirectories.
 
  ///
 
  /// \returns The module with the given name.
 
  Module *lookupModule(StringRef ModuleName,
 
                       SourceLocation ImportLoc = SourceLocation(),
 
                       bool AllowSearch = true,
 
                       bool AllowExtraModuleMapSearch = false);
 
 
 
  /// Try to find a module map file in the given directory, returning
 
  /// \c nullptr if none is found.
 
  const FileEntry *lookupModuleMapFile(const DirectoryEntry *Dir,
 
                                       bool IsFramework);
 
 
 
  /// Determine whether there is a module map that may map the header
 
  /// with the given file name to a (sub)module.
 
  /// Always returns false if modules are disabled.
 
  ///
 
  /// \param Filename The name of the file.
 
  ///
 
  /// \param Root The "root" directory, at which we should stop looking for
 
  /// module maps.
 
  ///
 
  /// \param IsSystem Whether the directories we're looking at are system
 
  /// header directories.
 
  bool hasModuleMap(StringRef Filename, const DirectoryEntry *Root,
 
                    bool IsSystem);
 
 
 
  /// Retrieve the module that corresponds to the given file, if any.
 
  ///
 
  /// \param File The header that we wish to map to a module.
 
  /// \param AllowTextual Whether we want to find textual headers too.
 
  ModuleMap::KnownHeader findModuleForHeader(const FileEntry *File,
 
                                             bool AllowTextual = false,
 
                                             bool AllowExcluded = false) const;
 
 
 
  /// Retrieve all the modules corresponding to the given file.
 
  ///
 
  /// \ref findModuleForHeader should typically be used instead of this.
 
  ArrayRef<ModuleMap::KnownHeader>
 
  findAllModulesForHeader(const FileEntry *File) const;
 
 
 
  /// Read the contents of the given module map file.
 
  ///
 
  /// \param File The module map file.
 
  /// \param IsSystem Whether this file is in a system header directory.
 
  /// \param ID If the module map file is already mapped (perhaps as part of
 
  ///        processing a preprocessed module), the ID of the file.
 
  /// \param Offset [inout] An offset within ID to start parsing. On exit,
 
  ///        filled by the end of the parsed contents (either EOF or the
 
  ///        location of an end-of-module-map pragma).
 
  /// \param OriginalModuleMapFile The original path to the module map file,
 
  ///        used to resolve paths within the module (this is required when
 
  ///        building the module from preprocessed source).
 
  /// \returns true if an error occurred, false otherwise.
 
  bool loadModuleMapFile(const FileEntry *File, bool IsSystem,
 
                         FileID ID = FileID(), unsigned *Offset = nullptr,
 
                         StringRef OriginalModuleMapFile = StringRef());
 
 
 
  /// Collect the set of all known, top-level modules.
 
  ///
 
  /// \param Modules Will be filled with the set of known, top-level modules.
 
  void collectAllModules(SmallVectorImpl<Module *> &Modules);
 
 
 
  /// Load all known, top-level system modules.
 
  void loadTopLevelSystemModules();
 
 
 
private:
 
  /// Lookup a module with the given module name and search-name.
 
  ///
 
  /// \param ModuleName The name of the module we're looking for.
 
  ///
 
  /// \param SearchName The "search-name" to derive filesystem paths from
 
  /// when looking for the module map; this is usually equal to ModuleName,
 
  /// but for compatibility with some buggy frameworks, additional attempts
 
  /// may be made to find the module under a related-but-different search-name.
 
  ///
 
  /// \param ImportLoc Location of the module include/import.
 
  ///
 
  /// \param AllowExtraModuleMapSearch Whether we allow to search modulemaps
 
  /// in subdirectories.
 
  ///
 
  /// \returns The module named ModuleName.
 
  Module *lookupModule(StringRef ModuleName, StringRef SearchName,
 
                       SourceLocation ImportLoc,
 
                       bool AllowExtraModuleMapSearch = false);
 
 
 
  /// Retrieve the name of the (to-be-)cached module file that should
 
  /// be used to load a module with the given name.
 
  ///
 
  /// \param ModuleName The module whose module file name will be returned.
 
  ///
 
  /// \param ModuleMapPath A path that when combined with \c ModuleName
 
  /// uniquely identifies this module. See Module::ModuleMap.
 
  ///
 
  /// \param CachePath A path to the module cache.
 
  ///
 
  /// \returns The name of the module file that corresponds to this module,
 
  /// or an empty string if this module does not correspond to any module file.
 
  std::string getCachedModuleFileNameImpl(StringRef ModuleName,
 
                                          StringRef ModuleMapPath,
 
                                          StringRef CachePath);
 
 
 
  /// Retrieve a module with the given name, which may be part of the
 
  /// given framework.
 
  ///
 
  /// \param Name The name of the module to retrieve.
 
  ///
 
  /// \param Dir The framework directory (e.g., ModuleName.framework).
 
  ///
 
  /// \param IsSystem Whether the framework directory is part of the system
 
  /// frameworks.
 
  ///
 
  /// \returns The module, if found; otherwise, null.
 
  Module *loadFrameworkModule(StringRef Name, DirectoryEntryRef Dir,
 
                              bool IsSystem);
 
 
 
  /// Load all of the module maps within the immediate subdirectories
 
  /// of the given search directory.
 
  void loadSubdirectoryModuleMaps(DirectoryLookup &SearchDir);
 
 
 
  /// Find and suggest a usable module for the given file.
 
  ///
 
  /// \return \c true if the file can be used, \c false if we are not permitted to
 
  ///         find this file due to requirements from \p RequestingModule.
 
  bool findUsableModuleForHeader(const FileEntry *File,
 
                                 const DirectoryEntry *Root,
 
                                 Module *RequestingModule,
 
                                 ModuleMap::KnownHeader *SuggestedModule,
 
                                 bool IsSystemHeaderDir);
 
 
 
  /// Find and suggest a usable module for the given file, which is part of
 
  /// the specified framework.
 
  ///
 
  /// \return \c true if the file can be used, \c false if we are not permitted to
 
  ///         find this file due to requirements from \p RequestingModule.
 
  bool findUsableModuleForFrameworkHeader(
 
      const FileEntry *File, StringRef FrameworkName, Module *RequestingModule,
 
      ModuleMap::KnownHeader *SuggestedModule, bool IsSystemFramework);
 
 
 
  /// Look up the file with the specified name and determine its owning
 
  /// module.
 
  OptionalFileEntryRef
 
  getFileAndSuggestModule(StringRef FileName, SourceLocation IncludeLoc,
 
                          const DirectoryEntry *Dir, bool IsSystemHeaderDir,
 
                          Module *RequestingModule,
 
                          ModuleMap::KnownHeader *SuggestedModule,
 
                          bool OpenFile = true, bool CacheFailures = true);
 
 
 
  /// Cache the result of a successful lookup at the given include location
 
  /// using the search path at \c HitIt.
 
  void cacheLookupSuccess(LookupFileCacheInfo &CacheLookup,
 
                          ConstSearchDirIterator HitIt,
 
                          SourceLocation IncludeLoc);
 
 
 
  /// Note that a lookup at the given include location was successful using the
 
  /// search path at index `HitIdx`.
 
  void noteLookupUsage(unsigned HitIdx, SourceLocation IncludeLoc);
 
 
 
public:
 
  /// Retrieve the module map.
 
  ModuleMap &getModuleMap() { return ModMap; }
 
 
 
  /// Retrieve the module map.
 
  const ModuleMap &getModuleMap() const { return ModMap; }
 
 
 
  unsigned header_file_size() const { return FileInfo.size(); }
 
 
 
  /// Return the HeaderFileInfo structure for the specified FileEntry,
 
  /// in preparation for updating it in some way.
 
  HeaderFileInfo &getFileInfo(const FileEntry *FE);
 
 
 
  /// Return the HeaderFileInfo structure for the specified FileEntry,
 
  /// if it has ever been filled in.
 
  /// \param WantExternal Whether the caller wants purely-external header file
 
  ///        info (where \p External is true).
 
  const HeaderFileInfo *getExistingFileInfo(const FileEntry *FE,
 
                                            bool WantExternal = true) const;
 
 
 
  SearchDirIterator search_dir_begin() { return {*this, 0}; }
 
  SearchDirIterator search_dir_end() { return {*this, SearchDirs.size()}; }
 
  SearchDirRange search_dir_range() {
 
    return {search_dir_begin(), search_dir_end()};
 
  }
 
 
 
  ConstSearchDirIterator search_dir_begin() const { return quoted_dir_begin(); }
 
  ConstSearchDirIterator search_dir_nth(size_t n) const {
 
    assert(n < SearchDirs.size());
 
    return {*this, n};
 
  }
 
  ConstSearchDirIterator search_dir_end() const { return system_dir_end(); }
 
  ConstSearchDirRange search_dir_range() const {
 
    return {search_dir_begin(), search_dir_end()};
 
  }
 
 
 
  unsigned search_dir_size() const { return SearchDirs.size(); }
 
 
 
  ConstSearchDirIterator quoted_dir_begin() const { return {*this, 0}; }
 
  ConstSearchDirIterator quoted_dir_end() const { return angled_dir_begin(); }
 
 
 
  ConstSearchDirIterator angled_dir_begin() const {
 
    return {*this, AngledDirIdx};
 
  }
 
  ConstSearchDirIterator angled_dir_end() const { return system_dir_begin(); }
 
 
 
  ConstSearchDirIterator system_dir_begin() const {
 
    return {*this, SystemDirIdx};
 
  }
 
  ConstSearchDirIterator system_dir_end() const {
 
    return {*this, SearchDirs.size()};
 
  }
 
 
 
  /// Get the index of the given search directory.
 
  unsigned searchDirIdx(const DirectoryLookup &DL) const;
 
 
 
  /// Retrieve a uniqued framework name.
 
  StringRef getUniqueFrameworkName(StringRef Framework);
 
 
 
  /// Retrieve the include name for the header.
 
  ///
 
  /// \param File The entry for a given header.
 
  /// \returns The name of how the file was included when the header's location
 
  /// was resolved.
 
  StringRef getIncludeNameForHeader(const FileEntry *File) const;
 
 
 
  /// Suggest a path by which the specified file could be found, for use in
 
  /// diagnostics to suggest a #include. Returned path will only contain forward
 
  /// slashes as separators. MainFile is the absolute path of the file that we
 
  /// are generating the diagnostics for. It will try to shorten the path using
 
  /// MainFile location, if none of the include search directories were prefix
 
  /// of File.
 
  ///
 
  /// \param IsSystem If non-null, filled in to indicate whether the suggested
 
  ///        path is relative to a system header directory.
 
  std::string suggestPathToFileForDiagnostics(const FileEntry *File,
 
                                              llvm::StringRef MainFile,
 
                                              bool *IsSystem = nullptr);
 
 
 
  /// Suggest a path by which the specified file could be found, for use in
 
  /// diagnostics to suggest a #include. Returned path will only contain forward
 
  /// slashes as separators. MainFile is the absolute path of the file that we
 
  /// are generating the diagnostics for. It will try to shorten the path using
 
  /// MainFile location, if none of the include search directories were prefix
 
  /// of File.
 
  ///
 
  /// \param WorkingDir If non-empty, this will be prepended to search directory
 
  /// paths that are relative.
 
  std::string suggestPathToFileForDiagnostics(llvm::StringRef File,
 
                                              llvm::StringRef WorkingDir,
 
                                              llvm::StringRef MainFile,
 
                                              bool *IsSystem = nullptr);
 
 
 
  void PrintStats();
 
 
 
  size_t getTotalMemory() const;
 
 
 
private:
 
  /// Describes what happened when we tried to load a module map file.
 
  enum LoadModuleMapResult {
 
    /// The module map file had already been loaded.
 
    LMM_AlreadyLoaded,
 
 
 
    /// The module map file was loaded by this invocation.
 
    LMM_NewlyLoaded,
 
 
 
    /// There is was directory with the given name.
 
    LMM_NoDirectory,
 
 
 
    /// There was either no module map file or the module map file was
 
    /// invalid.
 
    LMM_InvalidModuleMap
 
  };
 
 
 
  LoadModuleMapResult loadModuleMapFileImpl(const FileEntry *File,
 
                                            bool IsSystem,
 
                                            DirectoryEntryRef Dir,
 
                                            FileID ID = FileID(),
 
                                            unsigned *Offset = nullptr);
 
 
 
  /// Try to load the module map file in the given directory.
 
  ///
 
  /// \param DirName The name of the directory where we will look for a module
 
  /// map file.
 
  /// \param IsSystem Whether this is a system header directory.
 
  /// \param IsFramework Whether this is a framework directory.
 
  ///
 
  /// \returns The result of attempting to load the module map file from the
 
  /// named directory.
 
  LoadModuleMapResult loadModuleMapFile(StringRef DirName, bool IsSystem,
 
                                        bool IsFramework);
 
 
 
  /// Try to load the module map file in the given directory.
 
  ///
 
  /// \param Dir The directory where we will look for a module map file.
 
  /// \param IsSystem Whether this is a system header directory.
 
  /// \param IsFramework Whether this is a framework directory.
 
  ///
 
  /// \returns The result of attempting to load the module map file from the
 
  /// named directory.
 
  LoadModuleMapResult loadModuleMapFile(DirectoryEntryRef Dir, bool IsSystem,
 
                                        bool IsFramework);
 
};
 
 
 
/// Apply the header search options to get given HeaderSearch object.
 
void ApplyHeaderSearchOptions(HeaderSearch &HS,
 
                              const HeaderSearchOptions &HSOpts,
 
                              const LangOptions &Lang,
 
                              const llvm::Triple &triple);
 
 
 
} // namespace clang
 
 
 
#endif // LLVM_CLANG_LEX_HEADERSEARCH_H