C++ StringRef::substr方法代码示例

std::string Context::getThunkTarget(llvm::StringRef MangledName) {
  if (!isThunkSymbol(MangledName))
    return std::string();

  if (isMangledName(MangledName)) {
    // The targets of those thunks not derivable from the mangling.
    if (MangledName.endswith("TR") ||
        MangledName.endswith("Tr") ||
        MangledName.endswith("TW") )
      return std::string();

    if (MangledName.endswith("fC")) {
      std::string target = MangledName.str();
      target[target.size() - 1] = 'c';
      return target;
    }

    return MangledName.substr(0, MangledName.size() - 2).str();
  }
  // Old mangling.
  assert(MangledName.startswith("_T"));
  StringRef Remaining = MangledName.substr(2);
  if (Remaining.startswith("PA_"))
    return Remaining.substr(3).str();
  if (Remaining.startswith("PAo_"))
    return Remaining.substr(4).str();
  assert(Remaining.startswith("To") || Remaining.startswith("TO"));
  return std::string("_T") + Remaining.substr(2).str();
}

static inline void StripSpaces(llvm::StringRef &Str)
{
    while (!Str.empty() && isspace(Str[0]))
        Str = Str.substr(1);
    while (!Str.empty() && isspace(Str.back()))
        Str = Str.substr(0, Str.size()-1);
}

PythonObject PythonObject::ResolveName(llvm::StringRef name) const {
  // Resolve the name in the context of the specified object.  If, for example,
  // `this` refers to a PyModule, then this will look for `name` in this
  // module.  If `this` refers to a PyType, then it will resolve `name` as an
  // attribute of that type.  If `this` refers to an instance of an object,
  // then it will resolve `name` as the value of the specified field.
  //
  // This function handles dotted names so that, for example, if `m_py_obj`
  // refers to the `sys` module, and `name` == "path.append", then it will find
  // the function `sys.path.append`.

  size_t dot_pos = name.find('.');
  if (dot_pos == llvm::StringRef::npos) {
    // No dots in the name, we should be able to find the value immediately as
    // an attribute of `m_py_obj`.
    return GetAttributeValue(name);
  }

  // Look up the first piece of the name, and resolve the rest as a child of
  // that.
  PythonObject parent = ResolveName(name.substr(0, dot_pos));
  if (!parent.IsAllocated())
    return PythonObject();

  // Tail recursion.. should be optimized by the compiler
  return parent.ResolveName(name.substr(dot_pos + 1));
}

Symbol symbol(llvm::StringRef QName) {
  Symbol Sym;
  Sym.ID = SymbolID(QName.str());
  size_t Pos = QName.rfind("::");
  if (Pos == llvm::StringRef::npos) {
    Sym.Name = QName;
    Sym.Scope = "";
  } else {
    Sym.Name = QName.substr(Pos + 2);
    Sym.Scope = QName.substr(0, Pos + 2);
  }
  return Sym;
}

PythonObject
PythonObject::ResolveNameWithDictionary(llvm::StringRef name,
                                        const PythonDictionary &dict) {
  size_t dot_pos = name.find('.');
  llvm::StringRef piece = name.substr(0, dot_pos);
  PythonObject result = dict.GetItemForKey(PythonString(piece));
  if (dot_pos == llvm::StringRef::npos) {
    // There was no dot, we're done.
    return result;
  }

  // There was a dot.  The remaining portion of the name should be looked up in
  // the context of the object that was found in the dictionary.
  return result.ResolveName(name.substr(dot_pos + 1));
}

// Parses the contents of version.txt in an CUDA installation.  It should
// contain one line of the from e.g. "CUDA Version 7.5.2".
static CudaVersion ParseCudaVersionFile(llvm::StringRef V) {
  if (!V.startswith("CUDA Version "))
    return CudaVersion::UNKNOWN;
  V = V.substr(strlen("CUDA Version "));
  int Major = -1, Minor = -1;
  auto First = V.split('.');
  auto Second = First.second.split('.');
  if (First.first.getAsInteger(10, Major) ||
      Second.first.getAsInteger(10, Minor))
    return CudaVersion::UNKNOWN;

  if (Major == 7 && Minor == 0) {
    // This doesn't appear to ever happen -- version.txt doesn't exist in the
    // CUDA 7 installs I've seen.  But no harm in checking.
    return CudaVersion::CUDA_70;
  }
  if (Major == 7 && Minor == 5)
    return CudaVersion::CUDA_75;
  if (Major == 8 && Minor == 0)
    return CudaVersion::CUDA_80;
  if (Major == 9 && Minor == 0)
    return CudaVersion::CUDA_90;
  if (Major == 9 && Minor == 1)
    return CudaVersion::CUDA_91;
  return CudaVersion::UNKNOWN;
}

static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
                     const swift::Demangle::DemangleOptions &options) {
  bool hadLeadingUnderscore = false;
  if (name.startswith("__")) {
    hadLeadingUnderscore = true;
    name = name.substr(1);
  }
  swift::Demangle::NodePointer pointer =
      swift::demangle_wrappers::demangleSymbolAsNode(name);
  if (ExpandMode || TreeOnly) {
    llvm::outs() << "Demangling for " << name << '\n';
    swift::demangle_wrappers::NodeDumper(pointer).print(llvm::outs());
  }
  if (RemangleMode) {
    if (hadLeadingUnderscore) llvm::outs() << '_';
    // Just reprint the original mangled name if it didn't demangle.
    // This makes it easier to share the same database between the
    // mangling and demangling tests.
    if (!pointer) {
      llvm::outs() << name;
    } else {
      llvm::outs() << swift::Demangle::mangleNode(pointer);
    }
    return;
  }
  if (!TreeOnly) {
    std::string string = swift::Demangle::nodeToString(pointer, options);
    if (!CompactMode)
      llvm::outs() << name << " ---> ";
    llvm::outs() << (string.empty() ? name : llvm::StringRef(string));
  }
}

/// HandleComment - Hook into the preprocessor and extract comments containing
///  expected errors and warnings.
bool VerifyDiagnosticConsumer::HandleComment(Lexer &PP, const SourceLocation& CommentBegin, const llvm::StringRef &C) {
  const llvm::SourceMgr &SM = PP.getSourceManager();

  // If this comment is for a different source manager, ignore it.
  if (SrcManager && &SM != SrcManager)
    return false;

  if (C.empty())
    return false;

  // Fold any "\<EOL>" sequences
  size_t loc = C.find('\\');
  if (loc == StringRef::npos) {
    ParseDirective(C, &ED, SM, &PP, CommentBegin, Status);
    return false;
  }

  std::string C2;
  C2.reserve(C.size());

  for (size_t last = 0;; loc = C.find('\\', last)) {
    if (loc == StringRef::npos || loc == C.size()) {
      C2 += C.substr(last);
      break;
    }
    C2 += C.substr(last, loc-last);
    last = loc + 1;

    if (C[last] == '\n' || C[last] == '\r') {
      ++last;

      // Escape \r\n  or \n\r, but not \n\n.
      if (last < C.size())
        if (C[last] == '\n' || C[last] == '\r')
          if (C[last] != C[last-1])
            ++last;
    } else {
      // This was just a normal backslash.
      C2 += '\\';
    }
  }

  if (!C2.empty())
    ParseDirective(C2, &ED, SM, &PP, CommentBegin, Status);
  return false;
}

void InitHeaderSearch::AddDelimitedPaths(llvm::StringRef at) {
  if (at.empty()) // Empty string should not add '.' path.
    return;

  llvm::StringRef::size_type delim;
  while ((delim = at.find(llvm::sys::PathSeparator)) != llvm::StringRef::npos) {
    if (delim == 0)
      AddPath(".", Angled, false, true, false);
    else
      AddPath(at.substr(0, delim), Angled, false, true, false);
    at = at.substr(delim + 1);
  }

  if (at.empty())
    AddPath(".", Angled, false, true, false);
  else
    AddPath(at, Angled, false, true, false);
}

// Helpers to produce fake index symbols for memIndex() or completions().
// USRFormat is a regex replacement string for the unqualified part of the USR.
Symbol sym(llvm::StringRef QName, index::SymbolKind Kind,
           llvm::StringRef USRFormat) {
  Symbol Sym;
  std::string USR = "c:"; // We synthesize a few simple cases of USRs by hand!
  size_t Pos = QName.rfind("::");
  if (Pos == llvm::StringRef::npos) {
    Sym.Name = QName;
    Sym.Scope = "";
  } else {
    Sym.Name = QName.substr(Pos + 2);
    Sym.Scope = QName.substr(0, Pos + 2);
    USR += "@[email protected]" + replace(QName.substr(0, Pos), "::", "@[email protected]"); // ns:: -> @[email protected]
  }
  USR += llvm::Regex("^.*$").sub(USRFormat, Sym.Name); // e.g. func -> @[email protected]#
  Sym.ID = SymbolID(USR);
  Sym.SymInfo.Kind = Kind;
  Sym.Flags |= Symbol::IndexedForCodeCompletion;
  Sym.Origin = SymbolOrigin::Static;
  return Sym;
}

bool ProjectManager::shouldProcess(llvm::StringRef filename, ProjectInfo* project)
{
    if (!project)
        return false;
    if (project->type == ProjectInfo::External)
        return false;

    std::string fn = outputPrefix % "/" % project->name % "/" % filename.substr(project->source_path.size()) % ".html";
    return !llvm::sys::fs::exists(fn);
            // || boost::filesystem::last_write_time(p) < entry->getModificationTime();
}

bool Context::isThunkSymbol(llvm::StringRef MangledName) {
  if (isMangledName(MangledName)) {
    // First do a quick check
    if (MangledName.endswith("TA") ||  // partial application forwarder
        MangledName.endswith("Ta") ||  // ObjC partial application forwarder
        MangledName.endswith("To") ||  // swift-as-ObjC thunk
        MangledName.endswith("TO") ||  // ObjC-as-swift thunk
        MangledName.endswith("TR") ||  // reabstraction thunk helper function
        MangledName.endswith("Tr") ||  // reabstraction thunk
        MangledName.endswith("TW") ||  // protocol witness thunk
        MangledName.endswith("fC")) {  // allocating constructor

      // To avoid false positives, we need to fully demangle the symbol.
      NodePointer Nd = D->demangleSymbol(MangledName);
      if (!Nd || Nd->getKind() != Node::Kind::Global ||
          Nd->getNumChildren() == 0)
        return false;

      switch (Nd->getFirstChild()->getKind()) {
        case Node::Kind::ObjCAttribute:
        case Node::Kind::NonObjCAttribute:
        case Node::Kind::PartialApplyObjCForwarder:
        case Node::Kind::PartialApplyForwarder:
        case Node::Kind::ReabstractionThunkHelper:
        case Node::Kind::ReabstractionThunk:
        case Node::Kind::ProtocolWitness:
        case Node::Kind::Allocator:
          return true;
        default:
          break;
      }
    }
    return false;
  }

  if (MangledName.startswith("_T")) {
    // Old mangling.
    StringRef Remaining = MangledName.substr(2);
    if (Remaining.startswith("To") ||   // swift-as-ObjC thunk
        Remaining.startswith("TO") ||   // ObjC-as-swift thunk
        Remaining.startswith("PA_") ||  // partial application forwarder
        Remaining.startswith("PAo_")) { // ObjC partial application forwarder
      return true;
    }
  }
  return false;
}

static bool GetDescriptionSysV4L(llvm::StringRef path, std::string* desc) {
  llvm::SmallString<64> ifpath{"/sys/class/video4linux/"};
  ifpath += path.substr(5);
  ifpath += "/device/interface";

  int fd = open(ifpath.c_str(), O_RDONLY);
  if (fd < 0) return false;

  char readBuf[128];
  ssize_t n = read(fd, readBuf, sizeof(readBuf));
  close(fd);

  if (n <= 0) return false;

  *desc = llvm::StringRef(readBuf, n).rtrim();
  return true;
}

CompletionRequest::CompletionRequest(llvm::StringRef command_line,
                                     unsigned raw_cursor_pos,
                                     int match_start_point,
                                     int max_return_elements,
                                     CompletionResult &result)
    : m_command(command_line), m_raw_cursor_pos(raw_cursor_pos),
      m_match_start_point(match_start_point),
      m_max_return_elements(max_return_elements), m_result(result) {

  // We parse the argument up to the cursor, so the last argument in
  // parsed_line is the one containing the cursor, and the cursor is after the
  // last character.
  m_parsed_line = Args(command_line);
  m_partial_parsed_line = Args(command_line.substr(0, raw_cursor_pos));

  m_cursor_index = m_partial_parsed_line.GetArgumentCount() - 1;

  if (m_cursor_index == -1)
    m_cursor_char_position = 0;
  else
    m_cursor_char_position =
        strlen(m_partial_parsed_line.GetArgumentAtIndex(m_cursor_index));

  const char *cursor = command_line.data() + raw_cursor_pos;
  if (raw_cursor_pos > 0 && cursor[-1] == ' ') {
    // We are just after a space.  If we are in an argument, then we will
    // continue parsing, but if we are between arguments, then we have to
    // complete whatever the next element would be. We can distinguish the two
    // cases because if we are in an argument (e.g. because the space is
    // protected by a quote) then the space will also be in the parsed
    // argument...

    const char *current_elem =
        m_partial_parsed_line.GetArgumentAtIndex(m_cursor_index);
    if (m_cursor_char_position == 0 ||
        current_elem[m_cursor_char_position - 1] != ' ') {
      m_parsed_line.InsertArgumentAtIndex(m_cursor_index + 1, llvm::StringRef(),
                                          '\0');
      m_cursor_index++;
      m_cursor_char_position = 0;
    }
  }
}

bool GetSystemLibraryPaths(llvm::SmallVectorImpl<std::string>& Paths) {
#if defined(__APPLE__) || defined(__CYGWIN__)
  Paths.push_back("/usr/local/lib/");
  Paths.push_back("/usr/X11R6/lib/");
  Paths.push_back("/usr/lib/");
  Paths.push_back("/lib/");

 #ifndef __APPLE__
  Paths.push_back("/lib/x86_64-linux-gnu/");
  Paths.push_back("/usr/local/lib64/");
  Paths.push_back("/usr/lib64/");
  Paths.push_back("/lib64/");
 #endif
#else
  llvm::SmallString<1024> Buf;
  platform::Popen("LD_DEBUG=libs LD_PRELOAD=DOESNOTEXIST ls", Buf, true);
  const llvm::StringRef Result = Buf.str();

  const std::size_t NPos = std::string::npos;
  const std::size_t LD = Result.find("(LD_LIBRARY_PATH)");
  std::size_t From = Result.find("search path=", LD == NPos ? 0 : LD);
  if (From != NPos) {
    const std::size_t To = Result.find("(system search path)", From);
    if (To != NPos) {
      From += 12;
      std::string SysPath = Result.substr(From, To-From);
      SysPath.erase(std::remove_if(SysPath.begin(), SysPath.end(), isspace),
                    SysPath.end());

      llvm::SmallVector<llvm::StringRef, 10> CurPaths;
      SplitPaths(SysPath, CurPaths);
      for (const auto& Path : CurPaths)
        Paths.push_back(Path.str());
    }
  }
#endif
  return true;
}