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// target-select.cc -- select a target for an object file
// Copyright (C) 2006-2020 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.
#include "gold.h"
#include <cstdio>
#include <cstring>
#include "elfcpp.h"
#include "options.h"
#include "parameters.h"
#include "target-select.h"
namespace
{
// The start of the list of target selectors.
gold::Target_selector* target_selectors;
} // End anonymous namespace.
namespace gold
{
// Class Set_target_once.
void
Set_target_once::do_run_once(void*)
{
this->target_selector_->set_target();
}
// Construct a Target_selector, which means adding it to the linked
// list. This runs at global constructor time, so we want it to be
// fast.
Target_selector::Target_selector(int machine, int size, bool is_big_endian,
const char* bfd_name, const char* emulation)
: machine_(machine), size_(size), is_big_endian_(is_big_endian),
bfd_name_(bfd_name), emulation_(emulation), instantiated_target_(NULL),
set_target_once_(this)
{
this->next_ = target_selectors;
target_selectors = this;
}
// Instantiate the target and return it. Use SET_TARGET_ONCE_ to
// avoid instantiating two instances of the same target.
Target*
Target_selector::instantiate_target()
{
this->set_target_once_.run_once(NULL);
return this->instantiated_target_;
}
// Instantiate the target. This is called at most once.
void
Target_selector::set_target()
{
gold_assert(this->instantiated_target_ == NULL);
this->instantiated_target_ = this->do_instantiate_target();
}
// If we instantiated TARGET, return the corresponding BFD name.
const char*
Target_selector::do_target_bfd_name(const Target* target)
{
if (!this->is_our_target(target))
return NULL;
const char* my_bfd_name = this->bfd_name();
gold_assert(my_bfd_name != NULL);
return my_bfd_name;
}
// Find the target for an ELF file.
Target*
select_target(Input_file* input_file, off_t offset,
int machine, int size, bool is_big_endian,
int osabi, int abiversion)
{
for (Target_selector* p = target_selectors; p != NULL; p = p->next())
{
int pmach = p->machine();
if ((pmach == machine || pmach == elfcpp::EM_NONE)
&& p->get_size() == size
&& (p->is_big_endian() ? is_big_endian : !is_big_endian))
{
Target* ret = p->recognize(input_file, offset,
machine, osabi, abiversion);
if (ret != NULL)
return ret;
}
}
return NULL;
}
// Find a target using a BFD name. This is used to support the
// --oformat option.
Target*
select_target_by_bfd_name(const char* name)
{
for (Target_selector* p = target_selectors; p != NULL; p = p->next())
{
const char* pname = p->bfd_name();
if (pname == NULL || strcmp(pname, name) == 0)
{
Target* ret = p->recognize_by_bfd_name(name);
if (ret != NULL)
return ret;
}
}
return NULL;
}
// Find a target using a GNU linker emulation. This is used to
// support the -m option.
Target*
select_target_by_emulation(const char* name)
{
for (Target_selector* p = target_selectors; p != NULL; p = p->next())
{
const char* pname = p->emulation();
if (pname == NULL || strcmp(pname, name) == 0)
{
Target* ret = p->recognize_by_emulation(name);
if (ret != NULL)
return ret;
}
}
return NULL;
}
// Push all the supported BFD names onto a vector.
void
supported_target_names(std::vector<const char*>* names)
{
for (Target_selector* p = target_selectors; p != NULL; p = p->next())
p->supported_bfd_names(names);
}
// Push all the supported emulations onto a vector.
void
supported_emulation_names(std::vector<const char*>* names)
{
for (Target_selector* p = target_selectors; p != NULL; p = p->next())
p->supported_emulations(names);
}
// Implement the --print-output-format option.
void
print_output_format()
{
if (!parameters->target_valid())
{
// This case arises when --print-output-format is used with no
// input files. We need to come up with the right string to
// print based on the other options. If the user specified the
// format using a --oformat option, use that. That saves each
// target from having to remember the name that was used to
// select it. In other cases, we will just have to ask the
// target.
if (parameters->options().user_set_oformat())
{
const char* bfd_name = parameters->options().oformat();
Target* target = select_target_by_bfd_name(bfd_name);
if (target != NULL)
printf("%s\n", bfd_name);
else
gold_error(_("unrecognized output format %s"), bfd_name);
return;
}
parameters_force_valid_target();
}
const Target* target = ¶meters->target();
for (Target_selector* p = target_selectors; p != NULL; p = p->next())
{
const char* bfd_name = p->target_bfd_name(target);
if (bfd_name != NULL)
{
printf("%s\n", bfd_name);
return;
}
}
gold_unreachable();
}
} // End namespace gold.
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