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// archive.h -- archive support for gold      -*- C++ -*-

// Copyright 2006, 2007, 2008, 2010, 2011 Free Software Foundation, Inc.

// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation; either version 3 of the License, or

// (at your option) any later version.

// This program is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with this program; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,

// MA 02110-1301, USA.

#ifndef GOLD_ARCHIVE_H

#define GOLD_ARCHIVE_H

#include <string>

#include <vector>

#include "fileread.h"

#include "workqueue.h"

namespace gold

{

class Task;

class Input_argument;

class Input_file;

class Input_objects;

class Input_group;

class Layout;

class Symbol_table;

class Object;

class Read_symbols_data;

class Input_file_lib;

class Incremental_archive_entry;

// An entry in the archive map of offsets to members.

struct Archive_member

{

  Archive_member()

      : obj_(NULL), sd_(NULL), arg_serial_(0)

  { }

  Archive_member(Object* obj, Read_symbols_data* sd)

      : obj_(obj), sd_(sd), arg_serial_(0)

  { }

  // The object file.

  Object* obj_;

  // The data to pass from read_symbols() to add_symbols().

  Read_symbols_data* sd_;

  // The serial number of the file in the argument list.

  unsigned int arg_serial_;

};

// This class serves as a base class for Archive and Lib_group objects.

class Library_base

{

 public:

  Library_base(Task* task)

    : task_(task), incremental_info_(NULL)

  { }

  virtual

  ~Library_base()

  { }

  // The file name.

  const std::string&

  filename() const

  { return this->do_filename(); }

  // The modification time of the archive file.

  Timespec

  get_mtime()

  { return this->do_get_mtime(); }

  // When we see a symbol in an archive we might decide to include the member,

  // not include the member or be undecided. This enum represents these

  // possibilities.

  enum Should_include

  {

    SHOULD_INCLUDE_NO,

    SHOULD_INCLUDE_YES,

    SHOULD_INCLUDE_UNKNOWN

  };

  static Should_include

  should_include_member(Symbol_table* symtab, Layout*, const char* sym_name,

                        Symbol** symp, std::string* why, char** tmpbufp,

                        size_t* tmpbuflen);

  // Store a pointer to the incremental link info for the library.

  void

  set_incremental_info(Incremental_archive_entry* info)

  { this->incremental_info_ = info; }

  // Return the pointer to the incremental link info for the library.

  Incremental_archive_entry*

  incremental_info() const

  { return this->incremental_info_; }

  // Abstract base class for processing unused symbols.

  class Symbol_visitor_base

  {

   public:

    Symbol_visitor_base()

    { }

    virtual

    ~Symbol_visitor_base()

    { }

    // This function will be called for each unused global

    // symbol in a library, with a pointer to the symbol name.

    virtual void

    visit(const char* /* name */) = 0;

  };

  // Iterator for unused global symbols in the library.

  // Calls v->visit() for each global symbol defined

  // in each unused library member, passing a pointer to

  // the symbol name.

  void

  for_all_unused_symbols(Symbol_visitor_base* v) const

  { this->do_for_all_unused_symbols(v); }

 protected:

  // The task reading this archive.

  Task *task_;

 private:

  // The file name.

  virtual const std::string&

  do_filename() const = 0;

  // Return the modification time of the archive file.

  virtual Timespec

  do_get_mtime() = 0;

  // Iterator for unused global symbols in the library.

  virtual void

  do_for_all_unused_symbols(Symbol_visitor_base* v) const = 0;

  // The incremental link information for this archive.

  Incremental_archive_entry* incremental_info_;

};

// This class represents an archive--generally a libNAME.a file.

// Archives have a symbol table and a list of objects.

class Archive : public Library_base

{

 public:

  Archive(const std::string& name, Input_file* input_file,

          bool is_thin_archive, Dirsearch* dirpath, Task* task);

  // The length of the magic string at the start of an archive.

  static const int sarmag = 8;

  // The magic string at the start of an archive.

  static const char armag[sarmag];

  static const char armagt[sarmag];

  // The string expected at the end of an archive member header.

  static const char arfmag[2];

  // The name of the object.  This is the name used on the command

  // line; e.g., if "-lgcc" is on the command line, this will be

  // "gcc".

  const std::string&

  name() const

  { return this->name_; }

  // The input file.

  const Input_file*

  input_file() const

  { return this->input_file_; }

  // Set up the archive: read the symbol map.

  void

  setup();

  // Get a reference to the underlying file.

  File_read&

  file()

  { return this->input_file_->file(); }

  const File_read&

  file() const

  { return this->input_file_->file(); }

  // Lock the underlying file.

  void

  lock(const Task* t)

  { this->input_file_->file().lock(t); }

  // Unlock the underlying file.

  void

  unlock(const Task* t)

  { this->input_file_->file().unlock(t); }

  // Return whether the underlying file is locked.

  bool

  is_locked() const

  { return this->input_file_->file().is_locked(); }

  // Return the token, so that the task can be queued.

  Task_token*

  token()

  { return this->input_file_->file().token(); }

  // Release the underlying file.

  void

  release()

  { this->input_file_->file().release(); }

  // Clear uncached views in the underlying file.

  void

  clear_uncached_views()

  { this->input_file_->file().clear_uncached_views(); }

  // Whether this is a thin archive.

  bool

  is_thin_archive() const

  { return this->is_thin_archive_; }

  // Unlock any nested archives.

  void

  unlock_nested_archives();

  // Select members from the archive as needed and add them to the

  // link.

  bool

  add_symbols(Symbol_table*, Layout*, Input_objects*, Mapfile*);

  // Return whether the archive defines the symbol.

  bool

  defines_symbol(Symbol*) const;

  // Dump statistical information to stderr.

  static void

  print_stats();

  // Return the number of members in the archive.

  size_t

  count_members();

  // Return the no-export flag.

  bool

  no_export()

  { return this->no_export_; }

 private:

  Archive(const Archive&);

  Archive& operator=(const Archive&);

  // The file name.

  const std::string&

  do_filename() const

  { return this->input_file_->filename(); }

  // The modification time of the archive file.

  Timespec

  do_get_mtime()

  { return this->file().get_mtime(); }

  struct Archive_header;

  // Total number of archives seen.

  static unsigned int total_archives;

  // Total number of archive members seen.

  static unsigned int total_members;

  // Number of archive members loaded.

  static unsigned int total_members_loaded;

  // Get a view into the underlying file.

  const unsigned char*

  get_view(off_t start, section_size_type size, bool aligned, bool cache)

  { return this->input_file_->file().get_view(0, start, size, aligned, cache); }

  // Read the archive symbol map.

  void

  read_armap(off_t start, section_size_type size);

  // Read an archive member header at OFF.  CACHE is whether to cache

  // the file view.  Return the size of the member, and set *PNAME to

  // the name.

  off_t

  read_header(off_t off, bool cache, std::string* pname, off_t* nested_off);

  // Interpret an archive header HDR at OFF.  Return the size of the

  // member, and set *PNAME to the name.

  off_t

  interpret_header(const Archive_header* hdr, off_t off, std::string* pname,

                   off_t* nested_off) const;

  // Get the file and offset for an archive member, which may be an

  // external member of a thin archive.  Set *INPUT_FILE to the

  // file containing the actual member, *MEMOFF to the offset

  // within that file (0 if not a nested archive), and *MEMBER_NAME

  // to the name of the archive member.  Return TRUE on success.

  bool

  get_file_and_offset(off_t off, Input_file** input_file, off_t* memoff,

                      off_t* memsize, std::string* member_name);

  // Return an ELF object for the member at offset OFF.

  Object*

  get_elf_object_for_member(off_t off, bool*);

  // Read the symbols from all the archive members in the link.

  void

  read_all_symbols();

  // Read the symbols from an archive member in the link.  OFF is the file

  // offset of the member header.

  void

  read_symbols(off_t off);

  // Include all the archive members in the link.

  bool

  include_all_members(Symbol_table*, Layout*, Input_objects*, Mapfile*);

  // Include an archive member in the link.

  bool

  include_member(Symbol_table*, Layout*, Input_objects*, off_t off,

                 Mapfile*, Symbol*, const char* why);

  // Return whether we found this archive by searching a directory.

  bool

  searched_for() const

  { return this->input_file_->will_search_for(); }

  // Iterate over archive members.

  class const_iterator;

  const_iterator

  begin();

  const_iterator

  end();

  friend class const_iterator;

  // Iterator for unused global symbols in the library.

  void

  do_for_all_unused_symbols(Symbol_visitor_base* v) const;

  // An entry in the archive map of symbols to object files.

  struct Armap_entry

  {

    // The offset to the symbol name in armap_names_.

    off_t name_offset;

    // The file offset to the object in the archive.

    off_t file_offset;

  };

  // A simple hash code for off_t values.

  class Seen_hash

  {

   public:

    size_t operator()(off_t val) const

    { return static_cast<size_t>(val); }

  };

  // For keeping track of open nested archives in a thin archive file.

  typedef Unordered_map<std::string, Archive*> Nested_archive_table;

  // Name of object as printed to user.

  std::string name_;

  // For reading the file.

  Input_file* input_file_;

  // The archive map.

  std::vector<Armap_entry> armap_;

  // The names in the archive map.

  std::string armap_names_;

  // The extended name table.

  std::string extended_names_;

  // Track which symbols in the archive map are for elements which are

  // defined or which have already been included in the link.

  std::vector<bool> armap_checked_;

  // Track which elements have been included by offset.

  Unordered_set<off_t, Seen_hash> seen_offsets_;

  // Table of objects whose symbols have been pre-read.

  std::map<off_t, Archive_member> members_;

  // True if this is a thin archive.

  const bool is_thin_archive_;

  // True if we have included at least one object from this archive.

  bool included_member_;

  // Table of nested archives, indexed by filename.

  Nested_archive_table nested_archives_;

  // The directory search path.

  Dirsearch* dirpath_;

  // Number of members in this archive;

  unsigned int num_members_;

  // True if we exclude this library archive from automatic export.

  bool no_export_;

  // True if this library has been included as a --whole-archive.

  bool included_all_members_;

};

// This class is used to read an archive and pick out the desired

// elements and add them to the link.

class Add_archive_symbols : public Task

{

 public:

  Add_archive_symbols(Symbol_table* symtab, Layout* layout,

                      Input_objects* input_objects, Dirsearch* dirpath,

                      int dirindex, Mapfile* mapfile,

                      const Input_argument* input_argument,

                      Archive* archive, Input_group* input_group,

                      Task_token* this_blocker,

                      Task_token* next_blocker)

    : symtab_(symtab), layout_(layout), input_objects_(input_objects),

      dirpath_(dirpath), dirindex_(dirindex), mapfile_(mapfile),

      input_argument_(input_argument), archive_(archive),

      input_group_(input_group), this_blocker_(this_blocker),

      next_blocker_(next_blocker)

  { }

  ~Add_archive_symbols();

  // The standard Task methods.

  Task_token*

  is_runnable();

  void

  locks(Task_locker*);

  void

  run(Workqueue*);

  std::string

  get_name() const

  {

    if (this->archive_ == NULL)

      return "Add_archive_symbols";

    return "Add_archive_symbols " + this->archive_->file().filename();

  }

 private:

  Symbol_table* symtab_;

  Layout* layout_;

  Input_objects* input_objects_;

  Dirsearch* dirpath_;

  int dirindex_;

  Mapfile* mapfile_;

  const Input_argument* input_argument_;

  Archive* archive_;

  Input_group* input_group_;

  Task_token* this_blocker_;

  Task_token* next_blocker_;

};

// This class represents the files surrounded by a --start-lib ... --end-lib.

class Lib_group : public Library_base

{

 public:

  Lib_group(const Input_file_lib* lib, Task* task);

  // Select members from the lib group as needed and add them to the link.

  void

  add_symbols(Symbol_table*, Layout*, Input_objects*);

  // Include a member of the lib group in the link.

  void

  include_member(Symbol_table*, Layout*, Input_objects*, const Archive_member&);

  Archive_member*

  get_member(int i)

  {

    return &this->members_[i];

  }

  // Total number of archives seen.

  static unsigned int total_lib_groups;

  // Total number of archive members seen.

  static unsigned int total_members;

  // Number of archive members loaded.

  static unsigned int total_members_loaded;

  // Dump statistical information to stderr.

  static void

  print_stats();

 private:

  // The file name.

  const std::string&

  do_filename() const;

  // A Lib_group does not have a modification time, since there is no

  // real library file.

  Timespec

  do_get_mtime()

  { return Timespec(0, 0); }

  // Iterator for unused global symbols in the library.

  void

  do_for_all_unused_symbols(Symbol_visitor_base*) const;

  // For reading the files.

  const Input_file_lib* lib_;

  // Table of the objects in the group.

  std::vector<Archive_member> members_;

};

// This class is used to pick out the desired elements and add them to the link.

class Add_lib_group_symbols : public Task

{

 public:

  Add_lib_group_symbols(Symbol_table* symtab, Layout* layout,

                        Input_objects* input_objects,

                        Lib_group* lib, Task_token* next_blocker)

      : symtab_(symtab), layout_(layout), input_objects_(input_objects),

        lib_(lib), readsyms_blocker_(NULL), this_blocker_(NULL),

        next_blocker_(next_blocker)

  { }

  ~Add_lib_group_symbols();

  // The standard Task methods.

  Task_token*

  is_runnable();

  void

  locks(Task_locker*);

  void

  run(Workqueue*);

  // Set the blocker to use for this task.

  void

  set_blocker(Task_token* readsyms_blocker, Task_token* this_blocker)

  {

    gold_assert(this->readsyms_blocker_ == NULL && this->this_blocker_ == NULL);

    this->readsyms_blocker_ = readsyms_blocker;

    this->this_blocker_ = this_blocker;

  }

  std::string

  get_name() const

  {

    return "Add_lib_group_symbols";

  }

 private:

  Symbol_table* symtab_;

  Layout* layout_;

  Input_objects* input_objects_;

  Lib_group* lib_;

  Task_token* readsyms_blocker_;

  Task_token* this_blocker_;

  Task_token* next_blocker_;

};

} // End namespace gold.

#endif // !defined(GOLD_ARCHIVE_H)