gold/archive.h

   1 // archive.h -- archive support for gold      -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008 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 Task;
  35 class Input_file;
  36 class Input_objects;
  37 class Input_group;
  38 class Layout;
  39 class Symbol_table;
  40
  41 // This class represents an archive--generally a libNAME.a file.
  42 // Archives have a symbol table and a list of objects.
  43
  44 class Archive
  45 {
  46  public:
  47   Archive(const std::string& name, Input_file* input_file)
  48     : name_(name), input_file_(input_file), armap_(), armap_names_(),
  49       extended_names_(), armap_checked_(), seen_offsets_()
  50   { }
  51
  52   // The length of the magic string at the start of an archive.
  53   static const int sarmag = 8;
  54
  55   // The magic string at the start of an archive.
  56   static const char armag[sarmag];
  57
  58   // The string expected at the end of an archive member header.
  59   static const char arfmag[2];
  60
  61   // The name of the object.
  62   const std::string&
  63   name() const
  64   { return this->name_; }
  65
  66   // Set up the archive: read the symbol map.
  67   void
  68   setup(Task*);
  69
  70   // Get a reference to the underlying file.
  71   File_read&
  72   file()
  73   { return this->input_file_->file(); }
  74
  75   // Lock the underlying file.
  76   void
  77   lock(const Task* t)
  78   { this->input_file_->file().lock(t); }
  79
  80   // Unlock the underlying file.
  81   void
  82   unlock(const Task* t)
  83   { this->input_file_->file().unlock(t); }
  84
  85   // Return whether the underlying file is locked.
  86   bool
  87   is_locked() const
  88   { return this->input_file_->file().is_locked(); }
  89
  90   // Return the token, so that the task can be queued.
  91   Task_token*
  92   token()
  93   { return this->input_file_->file().token(); }
  94
  95   // Release the underlying file.
  96   void
  97   release()
  98   { this->input_file_->file().release(); }
  99
 100   // Select members from the archive as needed and add them to the
 101   // link.
 102   void
 103   add_symbols(Symbol_table*, Layout*, Input_objects*);
 104
 105  private:
 106   Archive(const Archive&);
 107   Archive& operator=(const Archive&);
 108
 109   struct Archive_header;
 110
 111   // Get a view into the underlying file.
 112   const unsigned char*
 113   get_view(off_t start, section_size_type size, bool cache)
 114   { return this->input_file_->file().get_view(start, size, cache); }
 115
 116   // Read the archive symbol map.
 117   void
 118   read_armap(off_t start, section_size_type size);
 119
 120   // Read an archive member header at OFF.  CACHE is whether to cache
 121   // the file view.  Return the size of the member, and set *PNAME to
 122   // the name.
 123   off_t
 124   read_header(off_t off, bool cache, std::string* pname);
 125
 126   // Interpret an archive header HDR at OFF.  Return the size of the
 127   // member, and set *PNAME to the name.
 128   off_t
 129   interpret_header(const Archive_header* hdr, off_t off, std::string* pname);
 130
 131   // Include all the archive members in the link.
 132   void
 133   include_all_members(Symbol_table*, Layout*, Input_objects*);
 134
 135   // Include an archive member in the link.
 136   void
 137   include_member(Symbol_table*, Layout*, Input_objects*, off_t off);
 138
 139   // An entry in the archive map of symbols to object files.
 140   struct Armap_entry
 141   {
 142     // The offset to the symbol name in armap_names_.
 143     off_t name_offset;
 144     // The file offset to the object in the archive.
 145     off_t file_offset;
 146   };
 147
 148   // A simple hash code for off_t values.
 149   class Seen_hash
 150   {
 151    public:
 152     size_t operator()(off_t val) const
 153     { return static_cast<size_t>(val); }
 154   };
 155
 156   // Name of object as printed to user.
 157   std::string name_;
 158   // For reading the file.
 159   Input_file* input_file_;
 160   // The archive map.
 161   std::vector<Armap_entry> armap_;
 162   // The names in the archive map.
 163   std::string armap_names_;
 164   // The extended name table.
 165   std::string extended_names_;
 166   // Track which symbols in the archive map are for elements which are
 167   // defined or which have already been included in the link.
 168   std::vector<bool> armap_checked_;
 169   // Track which elements have been included by offset.
 170   Unordered_set<off_t, Seen_hash> seen_offsets_;
 171 };
 172
 173 // This class is used to read an archive and pick out the desired
 174 // elements and add them to the link.
 175
 176 class Add_archive_symbols : public Task
 177 {
 178  public:
 179   Add_archive_symbols(Symbol_table* symtab, Layout* layout,
 180                       Input_objects* input_objects,
 181                       Archive* archive, Input_group* input_group,
 182                       Task_token* this_blocker,
 183                       Task_token* next_blocker)
 184     : symtab_(symtab), layout_(layout), input_objects_(input_objects),
 185       archive_(archive), input_group_(input_group),
 186       this_blocker_(this_blocker), next_blocker_(next_blocker)
 187   { }
 188
 189   ~Add_archive_symbols();
 190
 191   // The standard Task methods.
 192
 193   Task_token*
 194   is_runnable();
 195
 196   void
 197   locks(Task_locker*);
 198
 199   void
 200   run(Workqueue*);
 201
 202   std::string
 203   get_name() const
 204   {
 205     if (this->archive_ == NULL)
 206       return "Add_archive_symbols";
 207     return "Add_archive_symbols " + this->archive_->file().filename();
 208   }
 209
 210  private:
 211   Symbol_table* symtab_;
 212   Layout* layout_;
 213   Input_objects* input_objects_;
 214   Archive* archive_;
 215   Input_group* input_group_;
 216   Task_token* this_blocker_;
 217   Task_token* next_blocker_;
 218 };
 219
 220 } // End namespace gold.
 221
 222 #endif // !defined(GOLD_ARCHIVE_H)