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 "fileread.h"
  30 #include "workqueue.h"
  31
  32 namespace gold
  33 {
  34
  35 class Task;
  36 class Input_file;
  37 class Input_objects;
  38 class Input_group;
  39 class Layout;
  40 class Symbol_table;
  41
  42 // This class represents an archive--generally a libNAME.a file.
  43 // Archives have a symbol table and a list of objects.
  44
  45 class Archive
  46 {
  47  public:
  48   Archive(const std::string& name, Input_file* input_file,
  49           bool is_thin_archive, Dirsearch* dirpath, Task* task)
  50     : name_(name), input_file_(input_file), armap_(), armap_names_(),
  51       extended_names_(), armap_checked_(), seen_offsets_(),
  52       is_thin_archive_(is_thin_archive), dirpath_(dirpath), task_(task)
  53   { }
  54
  55   // The length of the magic string at the start of an archive.
  56   static const int sarmag = 8;
  57
  58   // The magic string at the start of an archive.
  59   static const char armag[sarmag];
  60   static const char armagt[sarmag];
  61
  62   // The string expected at the end of an archive member header.
  63   static const char arfmag[2];
  64
  65   // The name of the object.  This is the name used on the command
  66   // line; e.g., if "-lgcc" is on the command line, this will be
  67   // "gcc".
  68   const std::string&
  69   name() const
  70   { return this->name_; }
  71
  72   // The file name.
  73   const std::string&
  74   filename() const
  75   { return this->input_file_->filename(); }
  76
  77   // Set up the archive: read the symbol map.
  78   void
  79   setup();
  80
  81   // Get a reference to the underlying file.
  82   File_read&
  83   file()
  84   { return this->input_file_->file(); }
  85
  86   const File_read&
  87   file() const
  88   { return this->input_file_->file(); }
  89
  90   // Lock the underlying file.
  91   void
  92   lock(const Task* t)
  93   { this->input_file_->file().lock(t); }
  94
  95   // Unlock the underlying file.
  96   void
  97   unlock(const Task* t)
  98   { this->input_file_->file().unlock(t); }
  99
 100   // Return whether the underlying file is locked.
 101   bool
 102   is_locked() const
 103   { return this->input_file_->file().is_locked(); }
 104
 105   // Return the token, so that the task can be queued.
 106   Task_token*
 107   token()
 108   { return this->input_file_->file().token(); }
 109
 110   // Release the underlying file.
 111   void
 112   release()
 113   { this->input_file_->file().release(); }
 114
 115   // Clear uncached views in the underlying file.
 116   void
 117   clear_uncached_views()
 118   { this->input_file_->file().clear_uncached_views(); }
 119
 120   // Whether this is a thin archive.
 121   bool
 122   is_thin_archive() const
 123   { return this->is_thin_archive_; }
 124
 125   // Unlock any nested archives.
 126   void
 127   unlock_nested_archives();
 128
 129   // Select members from the archive as needed and add them to the
 130   // link.
 131   void
 132   add_symbols(Symbol_table*, Layout*, Input_objects*, Mapfile*);
 133
 134   // Return the number of members in the archive.
 135   size_t
 136   count_members() const;
 137
 138  private:
 139   Archive(const Archive&);
 140   Archive& operator=(const Archive&);
 141
 142   struct Archive_header;
 143
 144   // Get a view into the underlying file.
 145   const unsigned char*
 146   get_view(off_t start, section_size_type size, bool aligned, bool cache)
 147   { return this->input_file_->file().get_view(0, start, size, aligned, cache); }
 148
 149   // Read the archive symbol map.
 150   void
 151   read_armap(off_t start, section_size_type size);
 152
 153   // Read an archive member header at OFF.  CACHE is whether to cache
 154   // the file view.  Return the size of the member, and set *PNAME to
 155   // the name.
 156   off_t
 157   read_header(off_t off, bool cache, std::string* pname, off_t* nested_off);
 158
 159   // Interpret an archive header HDR at OFF.  Return the size of the
 160   // member, and set *PNAME to the name.
 161   off_t
 162   interpret_header(const Archive_header* hdr, off_t off, std::string* pname,
 163                    off_t* nested_off) const;
 164
 165   // Include all the archive members in the link.
 166   void
 167   include_all_members(Symbol_table*, Layout*, Input_objects*, Mapfile*);
 168
 169   // Include an archive member in the link.
 170   void
 171   include_member(Symbol_table*, Layout*, Input_objects*, off_t off,
 172                  Mapfile*, Symbol*, const char* why);
 173
 174   // Iterate over archive members.
 175   class const_iterator;
 176
 177   const_iterator
 178   begin() const;
 179
 180   const_iterator
 181   end() const;
 182
 183   friend class const_iterator;
 184
 185   // An entry in the archive map of symbols to object files.
 186   struct Armap_entry
 187   {
 188     // The offset to the symbol name in armap_names_.
 189     off_t name_offset;
 190     // The file offset to the object in the archive.
 191     off_t file_offset;
 192   };
 193
 194   // A simple hash code for off_t values.
 195   class Seen_hash
 196   {
 197    public:
 198     size_t operator()(off_t val) const
 199     { return static_cast<size_t>(val); }
 200   };
 201
 202   // For keeping track of open nested archives in a thin archive file.
 203   typedef Unordered_map<std::string, Archive*> Nested_archive_table;
 204
 205   // Name of object as printed to user.
 206   std::string name_;
 207   // For reading the file.
 208   Input_file* input_file_;
 209   // The archive map.
 210   std::vector<Armap_entry> armap_;
 211   // The names in the archive map.
 212   std::string armap_names_;
 213   // The extended name table.
 214   std::string extended_names_;
 215   // Track which symbols in the archive map are for elements which are
 216   // defined or which have already been included in the link.
 217   std::vector<bool> armap_checked_;
 218   // Track which elements have been included by offset.
 219   Unordered_set<off_t, Seen_hash> seen_offsets_;
 220   // True if this is a thin archive.
 221   const bool is_thin_archive_;
 222   // Table of nested archives, indexed by filename.
 223   Nested_archive_table nested_archives_;
 224   // The directory search path.
 225   Dirsearch* dirpath_;
 226   // The task reading this archive.
 227   Task *task_;
 228 };
 229
 230 // This class is used to read an archive and pick out the desired
 231 // elements and add them to the link.
 232
 233 class Add_archive_symbols : public Task
 234 {
 235  public:
 236   Add_archive_symbols(Symbol_table* symtab, Layout* layout,
 237                       Input_objects* input_objects, Mapfile* mapfile,
 238                       Archive* archive, Input_group* input_group,
 239                       Task_token* this_blocker,
 240                       Task_token* next_blocker)
 241     : symtab_(symtab), layout_(layout), input_objects_(input_objects),
 242       mapfile_(mapfile), archive_(archive), input_group_(input_group),
 243       this_blocker_(this_blocker), next_blocker_(next_blocker)
 244   { }
 245
 246   ~Add_archive_symbols();
 247
 248   // The standard Task methods.
 249
 250   Task_token*
 251   is_runnable();
 252
 253   void
 254   locks(Task_locker*);
 255
 256   void
 257   run(Workqueue*);
 258
 259   std::string
 260   get_name() const
 261   {
 262     if (this->archive_ == NULL)
 263       return "Add_archive_symbols";
 264     return "Add_archive_symbols " + this->archive_->file().filename();
 265   }
 266
 267  private:
 268   Symbol_table* symtab_;
 269   Layout* layout_;
 270   Input_objects* input_objects_;
 271   Mapfile* mapfile_;
 272   Archive* archive_;
 273   Input_group* input_group_;
 274   Task_token* this_blocker_;
 275   Task_token* next_blocker_;
 276 };
 277
 278 } // End namespace gold.
 279
 280 #endif // !defined(GOLD_ARCHIVE_H)