gold/archive.h

   1 // archive.h -- archive support for gold      -*- C++ -*-
   2
   3 // Copyright 2006, 2007 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #ifndef GOLD_ARCHIVE_H
  24 #define GOLD_ARCHIVE_H
  25
  26 #include <string>
  27 #include <vector>
  28
  29 #include "workqueue.h"
  30
  31 namespace gold
  32 {
  33
  34 class Input_file;
  35 class Input_objects;
  36 class Input_group;
  37 class Layout;
  38 class Symbol_table;
  39
  40 // This class represents an archive--generally a libNAME.a file.
  41 // Archives have a symbol table and a list of objects.
  42
  43 class Archive
  44 {
  45  public:
  46   Archive(const std::string& name, Input_file* input_file)
  47     : name_(name), input_file_(input_file), armap_(), armap_names_(),
  48       extended_names_(), armap_checked_(), seen_offsets_()
  49   { }
  50
  51   // The length of the magic string at the start of an archive.
  52   static const int sarmag = 8;
  53
  54   // The magic string at the start of an archive.
  55   static const char armag[sarmag];
  56
  57   // The string expected at the end of an archive member header.
  58   static const char arfmag[2];
  59
  60   // The name of the object.
  61   const std::string&
  62   name() const
  63   { return this->name_; }
  64
  65   // Set up the archive: read the symbol map.
  66   void
  67   setup();
  68
  69   // Get a reference to the underlying file.
  70   File_read&
  71   file()
  72   { return this->input_file_->file(); }
  73
  74   // Lock the underlying file.
  75   void
  76   lock()
  77   { this->input_file_->file().lock(); }
  78
  79   // Unlock the underlying file.
  80   void
  81   unlock()
  82   { this->input_file_->file().unlock(); }
  83
  84   // Return whether the underlying file is locked.
  85   bool
  86   is_locked() const
  87   { return this->input_file_->file().is_locked(); }
  88
  89   // Select members from the archive as needed and add them to the
  90   // link.
  91   void
  92   add_symbols(Symbol_table*, Layout*, Input_objects*);
  93
  94  private:
  95   Archive(const Archive&);
  96   Archive& operator=(const Archive&);
  97
  98   struct Archive_header;
  99
 100   // Get a view into the underlying file.
 101   const unsigned char*
 102   get_view(off_t start, off_t size, bool cache)
 103   { return this->input_file_->file().get_view(start, size, cache); }
 104
 105   // Read the archive symbol map.
 106   void
 107   read_armap(off_t start, off_t size);
 108
 109   // Read an archive member header at OFF.  Return the size of the
 110   // member, and set *PNAME to the name.
 111   off_t
 112   read_header(off_t off, std::string* pname);
 113
 114   // Interpret an archive header HDR at OFF.  Return the size of the
 115   // member, and set *PNAME to the name.
 116   off_t
 117   interpret_header(const Archive_header* hdr, off_t off, std::string* pname);
 118
 119   // Include all the archive members in the link.
 120   void
 121   include_all_members(Symbol_table*, Layout*, Input_objects*);
 122
 123   // Include an archive member in the link.
 124   void
 125   include_member(Symbol_table*, Layout*, Input_objects*, off_t off);
 126
 127   // An entry in the archive map of symbols to object files.
 128   struct Armap_entry
 129   {
 130     // The offset to the symbol name in armap_names_.
 131     off_t name_offset;
 132     // The file offset to the object in the archive.
 133     off_t file_offset;
 134   };
 135
 136   // A simple hash code for off_t values.
 137   class Seen_hash
 138   {
 139    public:
 140     size_t operator()(off_t val) const
 141     { return static_cast<size_t>(val); }
 142   };
 143
 144   // Name of object as printed to user.
 145   std::string name_;
 146   // For reading the file.
 147   Input_file* input_file_;
 148   // The archive map.
 149   std::vector<Armap_entry> armap_;
 150   // The names in the archive map.
 151   std::string armap_names_;
 152   // The extended name table.
 153   std::string extended_names_;
 154   // Track which symbols in the archive map are for elements which are
 155   // defined or which have already been included in the link.
 156   std::vector<bool> armap_checked_;
 157   // Track which elements have been included by offset.
 158   Unordered_set<off_t, Seen_hash> seen_offsets_;
 159 };
 160
 161 // This class is used to read an archive and pick out the desired
 162 // elements and add them to the link.
 163
 164 class Add_archive_symbols : public Task
 165 {
 166  public:
 167   Add_archive_symbols(Symbol_table* symtab, Layout* layout,
 168                       Input_objects* input_objects,
 169                       Archive* archive, Input_group* input_group,
 170                       Task_token* this_blocker,
 171                       Task_token* next_blocker)
 172     : symtab_(symtab), layout_(layout), input_objects_(input_objects),
 173       archive_(archive), input_group_(input_group),
 174       this_blocker_(this_blocker), next_blocker_(next_blocker)
 175   { }
 176
 177   ~Add_archive_symbols();
 178
 179   // The standard Task methods.
 180
 181   Is_runnable_type
 182   is_runnable(Workqueue*);
 183
 184   Task_locker*
 185   locks(Workqueue*);
 186
 187   void
 188   run(Workqueue*);
 189
 190  private:
 191   class Add_archive_symbols_locker;
 192
 193   Symbol_table* symtab_;
 194   Layout* layout_;
 195   Input_objects* input_objects_;
 196   Archive* archive_;
 197   Input_group* input_group_;
 198   Task_token* this_blocker_;
 199   Task_token* next_blocker_;
 200 };
 201
 202 } // End namespace gold.
 203
 204 #endif // !defined(GOLD_ARCHIVE_H)