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// target.cc
// Copyright 2009 Free Software Foundation, Inc.
// Written by Doug Kwan <dougkwan@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 "elfcpp.h"
#include "dynobj.h"
#include "symtab.h"
#include "output.h"
#include "target.h"
namespace gold
{
// Return whether NAME is a local label name. This is used to implement the
// --discard-locals options and can be overriden by children classes to
// implement system-specific behaviour. The logic here is the same as that
// in _bfd_elf_is_local_label_name().
bool
Target::do_is_local_label_name(const char* name) const
{
// Normal local symbols start with ``.L''.
if (name[0] == '.' && name[1] == 'L')
return true;
// At least some SVR4 compilers (e.g., UnixWare 2.1 cc) generate
// DWARF debugging symbols starting with ``..''.
if (name[0] == '.' && name[1] == '.')
return true;
// gcc will sometimes generate symbols beginning with ``_.L_'' when
// emitting DWARF debugging output. I suspect this is actually a
// small bug in gcc (it calls ASM_OUTPUT_LABEL when it should call
// ASM_GENERATE_INTERNAL_LABEL, and this causes the leading
// underscore to be emitted on some ELF targets). For ease of use,
// we treat such symbols as local.
if (name[0] == '_' && name[1] == '.' && name[2] == 'L' && name[3] == '_')
return true;
return false;
}
// Implementations of methods Target::do_make_elf_object are almost identical
// except for the address sizes and endianities. So we extract this
// into a template.
template<int size, bool big_endian>
inline Object*
Target::do_make_elf_object_implementation(
const std::string& name,
Input_file* input_file,
off_t offset,
const elfcpp::Ehdr<size, big_endian>& ehdr)
{
int et = ehdr.get_e_type();
if (et == elfcpp::ET_REL)
{
Sized_relobj<size, big_endian>* obj =
new Sized_relobj<size, big_endian>(name, input_file, offset, ehdr);
obj->setup();
return obj;
}
else if (et == elfcpp::ET_DYN)
{
Sized_dynobj<size, big_endian>* obj =
new Sized_dynobj<size, big_endian>(name, input_file, offset, ehdr);
obj->setup();
return obj;
}
else
{
gold_error(_("%s: unsupported ELF file type %d"),
name.c_str(), et);
return NULL;
}
}
// Make an ELF object called NAME by reading INPUT_FILE at OFFSET. EHDR
// is the ELF header of the object. There are four versions of this
// for different address sizes and endianities.
#ifdef HAVE_TARGET_32_LITTLE
Object*
Target::do_make_elf_object(const std::string& name, Input_file* input_file,
off_t offset, const elfcpp::Ehdr<32, false>& ehdr)
{
return this->do_make_elf_object_implementation<32, false>(name, input_file,
offset, ehdr);
}
#endif
#ifdef HAVE_TARGET_32_BIG
Object*
Target::do_make_elf_object(const std::string& name, Input_file* input_file,
off_t offset, const elfcpp::Ehdr<32, true>& ehdr)
{
return this->do_make_elf_object_implementation<32, true>(name, input_file,
offset, ehdr);
}
#endif
#ifdef HAVE_TARGET_64_LITTLE
Object*
Target::do_make_elf_object(const std::string& name, Input_file* input_file,
off_t offset, const elfcpp::Ehdr<64, false>& ehdr)
{
return this->do_make_elf_object_implementation<64, false>(name, input_file,
offset, ehdr);
}
#endif
#ifdef HAVE_TARGET_64_BIG
Object*
Target::do_make_elf_object(const std::string& name, Input_file* input_file,
off_t offset, const elfcpp::Ehdr<64, true>& ehdr)
{
return this->do_make_elf_object_implementation<64, true>(name, input_file,
offset, ehdr);
}
#endif
Output_section*
Target::do_make_output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags)
{
return new Output_section(name, type, flags);
}
// Default for whether a reloc is a call to a non-split function is
// whether the symbol is a function.
bool
Target::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
{
return sym->type() == elfcpp::STT_FUNC;
}
// Default conversion for -fsplit-stack is to give an error.
void
Target::do_calls_non_split(Relobj* object, unsigned int, section_offset_type,
section_size_type, unsigned char*, section_size_type,
std::string*, std::string*) const
{
static bool warned;
if (!warned)
{
gold_error(_("linker does not include stack split support "
"required by %s"),
object->name().c_str());
warned = true;
}
}
// Return whether BYTES/LEN matches VIEW/VIEW_SIZE at OFFSET.
bool
Target::match_view(const unsigned char* view, section_size_type view_size,
section_offset_type offset, const char* bytes,
size_t len) const
{
if (offset + len > view_size)
return false;
return memcmp(view + offset, bytes, len) == 0;
}
// Set the contents of a VIEW/VIEW_SIZE to nops starting at OFFSET
// for LEN bytes.
void
Target::set_view_to_nop(unsigned char* view, section_size_type view_size,
section_offset_type offset, size_t len) const
{
gold_assert(offset >= 0 && offset + len <= view_size);
if (!this->has_code_fill())
memset(view + offset, 0, len);
else
{
std::string fill = this->code_fill(len);
memcpy(view + offset, fill.data(), len);
}
}
} // End namespace gold.
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