Example #1
/// \brief Collect the set of header includes needed to construct the given 
/// module and update the TopHeaders file set of the module.
/// \param Module The module we're collecting includes from.
/// \param Includes Will be augmented with the set of \#includes or \#imports
/// needed to load all of the named headers.
static std::error_code
collectModuleHeaderIncludes(const LangOptions &LangOpts, FileManager &FileMgr,
                            ModuleMap &ModMap, clang::Module *Module,
                            SmallVectorImpl<char> &Includes) {
  // Don't collect any headers for unavailable modules.
  if (!Module->isAvailable())
    return std::error_code();

  // Add includes for each of these headers.
  for (auto HK : {Module::HK_Normal, Module::HK_Private}) {
    for (Module::Header &H : Module->Headers[HK]) {
      // Use the path as specified in the module map file. We'll look for this
      // file relative to the module build directory (the directory containing
      // the module map file) so this will find the same file that we found
      // while parsing the module map.
      addHeaderInclude(H.NameAsWritten, Includes, LangOpts, Module->IsExternC);
  // Note that Module->PrivateHeaders will not be a TopHeader.

  if (Module::Header UmbrellaHeader = Module->getUmbrellaHeader()) {
    if (Module->Parent)
      // Include the umbrella header for submodules.
      addHeaderInclude(UmbrellaHeader.NameAsWritten, Includes, LangOpts,
  } else if (Module::DirectoryName UmbrellaDir = Module->getUmbrellaDir()) {
    // Add all of the headers we find in this subdirectory.
    std::error_code EC;
    SmallString<128> DirNative;
    llvm::sys::path::native(UmbrellaDir.Entry->getName(), DirNative);

    vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
    for (vfs::recursive_directory_iterator Dir(FS, DirNative, EC), End;
         Dir != End && !EC; Dir.increment(EC)) {
      // Check whether this entry has an extension typically associated with 
      // headers.
      if (!llvm::StringSwitch<bool>(llvm::sys::path::extension(Dir->getName()))
          .Cases(".h", ".H", ".hh", ".hpp", true)

      const FileEntry *Header = FileMgr.getFile(Dir->getName());
      // FIXME: This shouldn't happen unless there is a file system race. Is
      // that worth diagnosing?
      if (!Header)

      // If this header is marked 'unavailable' in this module, don't include 
      // it.
      if (ModMap.isHeaderUnavailableInModule(Header, Module))

      // Compute the relative path from the directory to this file.
      SmallVector<StringRef, 16> Components;
      auto PathIt = llvm::sys::path::rbegin(Dir->getName());
      for (int I = 0; I != Dir.level() + 1; ++I, ++PathIt)
      SmallString<128> RelativeHeader(UmbrellaDir.NameAsWritten);
      for (auto It = Components.rbegin(), End = Components.rend(); It != End;
        llvm::sys::path::append(RelativeHeader, *It);

      // Include this header as part of the umbrella directory.
      addHeaderInclude(RelativeHeader, Includes, LangOpts, Module->IsExternC);

    if (EC)
      return EC;

  // Recurse into submodules.
  for (clang::Module::submodule_iterator Sub = Module->submodule_begin(),
                                      SubEnd = Module->submodule_end();
       Sub != SubEnd; ++Sub)
    if (std::error_code Err = collectModuleHeaderIncludes(
            LangOpts, FileMgr, ModMap, *Sub, Includes))
      return Err;

  return std::error_code();