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 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, off_t 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, off_t size);
 119
 120   // Read an archive member header at OFF.  Return the size of the
 121   // member, and set *PNAME to the name.
 122   off_t
 123   read_header(off_t off, std::string* pname);
 124
 125   // Interpret an archive header HDR at OFF.  Return the size of the
 126   // member, and set *PNAME to the name.
 127   off_t
 128   interpret_header(const Archive_header* hdr, off_t off, std::string* pname);
 129
 130   // Include all the archive members in the link.
 131   void
 132   include_all_members(Symbol_table*, Layout*, Input_objects*);
 133
 134   // Include an archive member in the link.
 135   void
 136   include_member(Symbol_table*, Layout*, Input_objects*, off_t off);
 137
 138   // An entry in the archive map of symbols to object files.
 139   struct Armap_entry
 140   {
 141     // The offset to the symbol name in armap_names_.
 142     off_t name_offset;
 143     // The file offset to the object in the archive.
 144     off_t file_offset;
 145   };
 146
 147   // A simple hash code for off_t values.
 148   class Seen_hash
 149   {
 150    public:
 151     size_t operator()(off_t val) const
 152     { return static_cast<size_t>(val); }
 153   };
 154
 155   // Name of object as printed to user.
 156   std::string name_;
 157   // For reading the file.
 158   Input_file* input_file_;
 159   // The archive map.
 160   std::vector<Armap_entry> armap_;
 161   // The names in the archive map.
 162   std::string armap_names_;
 163   // The extended name table.
 164   std::string extended_names_;
 165   // Track which symbols in the archive map are for elements which are
 166   // defined or which have already been included in the link.
 167   std::vector<bool> armap_checked_;
 168   // Track which elements have been included by offset.
 169   Unordered_set<off_t, Seen_hash> seen_offsets_;
 170 };
 171
 172 // This class is used to read an archive and pick out the desired
 173 // elements and add them to the link.
 174
 175 class Add_archive_symbols : public Task
 176 {
 177  public:
 178   Add_archive_symbols(Symbol_table* symtab, Layout* layout,
 179                       Input_objects* input_objects,
 180                       Archive* archive, Input_group* input_group,
 181                       Task_token* this_blocker,
 182                       Task_token* next_blocker)
 183     : symtab_(symtab), layout_(layout), input_objects_(input_objects),
 184       archive_(archive), input_group_(input_group),
 185       this_blocker_(this_blocker), next_blocker_(next_blocker)
 186   { }
 187
 188   ~Add_archive_symbols();
 189
 190   // The standard Task methods.
 191
 192   Task_token*
 193   is_runnable();
 194
 195   void
 196   locks(Task_locker*);
 197
 198   void
 199   run(Workqueue*);
 200
 201   std::string
 202   get_name() const
 203   {
 204     if (this->archive_ == NULL)
 205       return "Add_archive_symbols";
 206     return "Add_archive_symbols " + this->archive_->file().filename();
 207   }
 208
 209  private:
 210   Symbol_table* symtab_;
 211   Layout* layout_;
 212   Input_objects* input_objects_;
 213   Archive* archive_;
 214   Input_group* input_group_;
 215   Task_token* this_blocker_;
 216   Task_token* next_blocker_;
 217 };
 218
 219 } // End namespace gold.
 220
 221 #endif // !defined(GOLD_ARCHIVE_H)