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