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