gold/target-select.h

// target-select.h -- select a target for an object file  -*- C++ -*-

#ifndef GOLD_TARGET_SELECT_H
#define GOLD_TARGET_SELECT_H

namespace gold
{

class Target;

// We want to avoid a master list of targets, which implies using a
// global constructor.  And we also want the program to start up as
// quickly as possible, which implies avoiding global constructors.
// We compromise on a very simple global constructor.  We use a target
// selector, which specifies an ELF machine number and a recognition
// function.  We use global constructors to build a linked list of
// target selectors--a simple pointer list, not a std::list.

class Target_selector
{
 public:
  // Create a target selector for a specific machine number, size (32
  // or 64), and endianness.  The machine number can be EM_NONE to
  // test for any machine number.
  Target_selector(int machine, int size, bool big_endian);

  virtual ~Target_selector()
  { }

  // If we can handle this target, return a pointer to a target
  // structure.  The size and endianness are known.
  virtual Target* recognize(int machine, int osabi, int abiversion) = 0;

  // Return the next Target_selector in the linked list.
  Target_selector*
  next() const
  { return this->next_; }

  // Return the machine number this selector is looking for, which can
  // be EM_NONE to match any machine number.
  int
  machine() const
  { return this->machine_; }

  // Return the size this is looking for (32 or 64).
  int
  size() const
  { return this->size_; }

  // Return the endianness this is looking for.
  bool
  big_endian() const
  { return this->big_endian_; }

 private:
  int machine_;
  int size_;
  bool big_endian_;
  Target_selector* next_;
};

// Select the target for an ELF file.

extern Target* select_target(int machine, int size, bool big_endian,
			     int osabi, int abiversion);

} // End namespace gold.

#endif // !defined(GOLD_TARGET_SELECT_H)