gold/target-select.h

   1 // target-select.h -- select a target for an object file  -*- 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_TARGET_SELECT_H
  24 #define GOLD_TARGET_SELECT_H
  25
  26 namespace gold
  27 {
  28
  29 class Target;
  30
  31 // We want to avoid a master list of targets, which implies using a
  32 // global constructor.  And we also want the program to start up as
  33 // quickly as possible, which implies avoiding global constructors.
  34 // We compromise on a very simple global constructor.  We use a target
  35 // selector, which specifies an ELF machine number and a recognition
  36 // function.  We use global constructors to build a linked list of
  37 // target selectors--a simple pointer list, not a std::list.
  38
  39 class Target_selector
  40 {
  41  public:
  42   // Create a target selector for a specific machine number, size (32
  43   // or 64), and endianness.  The machine number can be EM_NONE to
  44   // test for any machine number.
  45   Target_selector(int machine, int size, bool big_endian);
  46
  47   virtual ~Target_selector()
  48   { }
  49
  50   // If we can handle this target, return a pointer to a target
  51   // structure.  The size and endianness are known.
  52   virtual Target* recognize(int machine, int osabi, int abiversion) = 0;
  53
  54   // Return the next Target_selector in the linked list.
  55   Target_selector*
  56   next() const
  57   { return this->next_; }
  58
  59   // Return the machine number this selector is looking for, which can
  60   // be EM_NONE to match any machine number.
  61   int
  62   machine() const
  63   { return this->machine_; }
  64
  65   // Return the size this is looking for (32 or 64).
  66   int
  67   size() const
  68   { return this->size_; }
  69
  70   // Return the endianness this is looking for.
  71   bool
  72   big_endian() const
  73   { return this->big_endian_; }
  74
  75  private:
  76   int machine_;
  77   int size_;
  78   bool big_endian_;
  79   Target_selector* next_;
  80 };
  81
  82 // Select the target for an ELF file.
  83
  84 extern Target* select_target(int machine, int size, bool big_endian,
  85                              int osabi, int abiversion);
  86
  87 } // End namespace gold.
  88
  89 #endif // !defined(GOLD_TARGET_SELECT_H)