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