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// target-select.h -- select a target for an object file -*- C++ -*-
// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.
#ifndef GOLD_TARGET_SELECT_H
#define GOLD_TARGET_SELECT_H
#include <vector>
#include "gold-threads.h"
namespace gold
{
class Target;
class Target_selector;
// Used to set the target only once.
class Set_target_once : public Once
{
public:
Set_target_once(Target_selector* target_selector)
: target_selector_(target_selector)
{ }
protected:
void
do_run_once(void*);
private:
Target_selector* target_selector_;
};
// 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. BFD_NAME is the name of the target
// used by the GNU linker, for backward compatibility; it may be
// NULL.
Target_selector(int machine, int size, bool is_big_endian,
const char* bfd_name);
virtual ~Target_selector()
{ }
// If we can handle this target, return a pointer to a target
// structure. The size and endianness are known.
Target*
recognize(int machine, int osabi, int abiversion)
{ return this->do_recognize(machine, osabi, abiversion); }
// If NAME matches the target, return a pointer to a target
// structure.
Target*
recognize_by_name(const char* name)
{ return this->do_recognize_by_name(name); }
// Push all supported names onto the vector. This is only used for
// help output.
void
supported_names(std::vector<const char*>* names)
{ this->do_supported_names(names); }
// 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. This can
// be EM_NONE to match any machine number, in which case the
// do_recognize hook will be responsible for matching the machine
// number.
int
machine() const
{ return this->machine_; }
// Return the size this is looking for (32 or 64).
int
get_size() const
{ return this->size_; }
// Return the endianness this is looking for.
bool
is_big_endian() const
{ return this->is_big_endian_; }
// Return the BFD name. This may return NULL, in which case the
// do_recognize_by_name hook will be responsible for matching the
// BFD name.
const char*
bfd_name() const
{ return this->bfd_name_; }
protected:
// Return an instance of the real target. This must be implemented
// by the child class.
virtual Target*
do_instantiate_target() = 0;
// Recognize an object file given a machine code, OSABI code, and
// ELF version value. When this is called we already know that they
// match the machine_, size_, and is_big_endian_ fields. The child
// class may implement a different version of this to do additional
// checks, or to check for multiple machine codes if the machine_
// field is EM_NONE.
virtual Target*
do_recognize(int, int, int)
{ return this->instantiate_target(); }
// Recognize a target by name. When this is called we already know
// that the name matches (or that the bfd_name_ field is NULL). The
// child class may implement a different version of this to
// recognize more than one name.
virtual Target*
do_recognize_by_name(const char*)
{ return this->instantiate_target(); }
// Return a list of supported BFD names. The child class may
// implement a different version of this to handle more than one
// name.
virtual void
do_supported_names(std::vector<const char*>* names)
{
gold_assert(this->bfd_name_ != NULL);
names->push_back(this->bfd_name_);
}
// Instantiate the target and return it.
Target*
instantiate_target();
private:
// Set the target.
void
set_target();
friend class Set_target_once;
// ELF machine code.
const int machine_;
// Target size--32 or 64.
const int size_;
// Whether the target is big endian.
const bool is_big_endian_;
// BFD name of target, for compatibility.
const char* const bfd_name_;
// Next entry in list built at global constructor time.
Target_selector* next_;
// The singleton Target structure--this points to an instance of the
// real implementation.
Target* instantiated_target_;
// Used to set the target only once.
Set_target_once set_target_once_;
};
// Select the target for an ELF file.
extern Target*
select_target(int machine, int size, bool big_endian, int osabi,
int abiversion);
// Select a target using a BFD name.
extern Target*
select_target_by_name(const char* name);
// Fill in a vector with the list of supported targets. This returns
// a list of BFD names.
extern void
supported_target_names(std::vector<const char*>*);
} // End namespace gold.
#endif // !defined(GOLD_TARGET_SELECT_H)
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