C++ Path::isArchive方法代码示例

/// LinkInArchive - opens an archive library and link in all objects which
/// provide symbols that are currently undefined.
///
/// Inputs:
///  Filename - The pathname of the archive.
///
/// Return Value:
///  TRUE  - An error occurred.
///  FALSE - No errors.
bool
Linker::LinkInArchive(const sys::Path &Filename, bool &is_native) {
  // Make sure this is an archive file we're dealing with
  if (!Filename.isArchive())
    return error("File '" + Filename.toString() + "' is not an archive.");

  // Open the archive file
  verbose("Linking archive file '" + Filename.toString() + "'");

  // Find all of the symbols currently undefined in the bitcode program.
  // If all the symbols are defined, the program is complete, and there is
  // no reason to link in any archive files.
  std::set<std::string> UndefinedSymbols;
  GetAllUndefinedSymbols(Composite, UndefinedSymbols);

  if (UndefinedSymbols.empty()) {
    verbose("No symbols undefined, skipping library '" +
            Filename.toString() + "'");
    return false;  // No need to link anything in!
  }

  std::string ErrMsg;
  std::auto_ptr<Archive> AutoArch (
    Archive::OpenAndLoadSymbols(Filename, Context, &ErrMsg));

  Archive* arch = AutoArch.get();

  if (!arch)
    return error("Cannot read archive '" + Filename.toString() +
                 "': " + ErrMsg);
  if (!arch->isBitcodeArchive()) {
    is_native = true;
    return false;
  }
  is_native = false;

  // Save a set of symbols that are not defined by the archive. Since we're
  // entering a loop, there's no point searching for these multiple times. This
  // variable is used to "set_subtract" from the set of undefined symbols.
  std::set<std::string> NotDefinedByArchive;

  // Save the current set of undefined symbols, because we may have to make
  // multiple passes over the archive:
  std::set<std::string> CurrentlyUndefinedSymbols;

  do {
    CurrentlyUndefinedSymbols = UndefinedSymbols;

    // Find the modules we need to link into the target module
    std::set<ModuleProvider*> Modules;
    if (!arch->findModulesDefiningSymbols(UndefinedSymbols, Modules, &ErrMsg))
      return error("Cannot find symbols in '" + Filename.toString() + 
                   "': " + ErrMsg);

    // If we didn't find any more modules to link this time, we are done
    // searching this archive.
    if (Modules.empty())
      break;

    // Any symbols remaining in UndefinedSymbols after
    // findModulesDefiningSymbols are ones that the archive does not define. So
    // we add them to the NotDefinedByArchive variable now.
    NotDefinedByArchive.insert(UndefinedSymbols.begin(),
        UndefinedSymbols.end());

    // Loop over all the ModuleProviders that we got back from the archive
    for (std::set<ModuleProvider*>::iterator I=Modules.begin(), E=Modules.end();
         I != E; ++I) {

      // Get the module we must link in.
      std::string moduleErrorMsg;
      std::auto_ptr<Module> AutoModule((*I)->releaseModule( &moduleErrorMsg ));
      if (!moduleErrorMsg.empty())
        return error("Could not load a module: " + moduleErrorMsg);

      Module* aModule = AutoModule.get();

      if (aModule != NULL) {
        verbose("  Linking in module: " + aModule->getModuleIdentifier());

        // Link it in
        if (LinkInModule(aModule, &moduleErrorMsg)) {
          return error("Cannot link in module '" +
                       aModule->getModuleIdentifier() + "': " + moduleErrorMsg);
        }
      } 
    }
    
    // Get the undefined symbols from the aggregate module. This recomputes the
    // symbols we still need after the new modules have been linked in.
    GetAllUndefinedSymbols(Composite, UndefinedSymbols);
//.........这里部分代码省略.........