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binutils-gdb/gold/output.cc
Doug Kwan 131687b4ad 2010-07-13 Doug Kwan <dougkwan@google.com> 
* arm.cc (Arm_input_section::Arm_input_section): For a
	SHT_ARM_EXIDX section, always keeps the input sections.
	(Arm_input_section::set_exidx_section_link): New method.
	(Arm_exidx_input_section::Arm_exidx_input_section): Initialize
	has_errors_ to false.
	(Arm_exidx_input_section::has_errors,
	Arm_exidx_input_section::set_has_errors): New methods.
	(Arm_exidx_input_section::has_errors_): New data member.
	(Arm_relobj::get_exidx_shndx_list): New method.
	(Arm_output_section::append_text_sections_to_list): Do not skip
	section without SHF_EXECINSTR.
	(Arm_output_section::fix_exidx_coverage): Skip input sections with
	errors.
 	(Arm_relobj::make_exidx_input_section): Add new parameter for text
	section header.  Make error messages more verbose.  Check for
	a non-executable section linked to an EXIDX section.
	(Arm_relobj::do_read_symbols): Remove error checking, which has been
	moved to Arm_relobj::make_exidx_input_section.  Add an assertion to
	check that there is no deferred EXIDX section if we exit early.
	Instead of not making an EXIDX section in case of an error, make one
	and set the has_errors flag of it.
	(Target_arm::do_finalize_sections): Fix up links of EXIDX sections
	in a relocatable link.
	(Target_arm::do_relax): Look for the EXIDX output section instead of
	assuming that it is called .ARM.exidx.
 	(Target_arm::fix_exidx_coverage): Add a new parameter for input
	section list.  Do not check for SHF_EXECINSTR section flags but
	skip any input section with errors.
	* output.cc (Output_section::Output_section): Initialize
	always_keeps_input_sections_ to false.
	(Output_section::add_input_section): Check for
	always_keeps_input_sections_.
	*  output.h (Output_section::always_keeps_input_sections,
	Output_section::set_always_keeps_input_sections): New methods.
	(Output_section::always_keeps_input_sections): New data member.
2010-07-13 20:07:08 +00:00

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// output.cc -- manage the output file for gold
// Copyright 2006, 2007, 2008, 2009 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 <cstdlib>
#include <cstring>
#include <cerrno>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <algorithm>
#include "libiberty.h"
#include "parameters.h"
#include "object.h"
#include "symtab.h"
#include "reloc.h"
#include "merge.h"
#include "descriptors.h"
#include "output.h"
// Some BSD systems still use MAP_ANON instead of MAP_ANONYMOUS
#ifndef MAP_ANONYMOUS
# define MAP_ANONYMOUS MAP_ANON
#endif
#ifndef HAVE_POSIX_FALLOCATE
// A dummy, non general, version of posix_fallocate. Here we just set
// the file size and hope that there is enough disk space. FIXME: We
// could allocate disk space by walking block by block and writing a
// zero byte into each block.
static int
posix_fallocate(int o, off_t offset, off_t len)
{
return ftruncate(o, offset + len);
}
#endif // !defined(HAVE_POSIX_FALLOCATE)
namespace gold
{
// Output_data variables.
bool Output_data::allocated_sizes_are_fixed;
// Output_data methods.
Output_data::~Output_data()
{
}
// Return the default alignment for the target size.
uint64_t
Output_data::default_alignment()
{
return Output_data::default_alignment_for_size(
parameters->target().get_size());
}
// Return the default alignment for a size--32 or 64.
uint64_t
Output_data::default_alignment_for_size(int size)
{
if (size == 32)
return 4;
else if (size == 64)
return 8;
else
gold_unreachable();
}
// Output_section_header methods. This currently assumes that the
// segment and section lists are complete at construction time.
Output_section_headers::Output_section_headers(
const Layout* layout,
const Layout::Segment_list* segment_list,
const Layout::Section_list* section_list,
const Layout::Section_list* unattached_section_list,
const Stringpool* secnamepool,
const Output_section* shstrtab_section)
: layout_(layout),
segment_list_(segment_list),
section_list_(section_list),
unattached_section_list_(unattached_section_list),
secnamepool_(secnamepool),
shstrtab_section_(shstrtab_section)
{
}
// Compute the current data size.
off_t
Output_section_headers::do_size() const
{
// Count all the sections. Start with 1 for the null section.
off_t count = 1;
if (!parameters->options().relocatable())
{
for (Layout::Segment_list::const_iterator p =
this->segment_list_->begin();
p != this->segment_list_->end();
++p)
if ((*p)->type() == elfcpp::PT_LOAD)
count += (*p)->output_section_count();
}
else
{
for (Layout::Section_list::const_iterator p =
this->section_list_->begin();
p != this->section_list_->end();
++p)
if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
++count;
}
count += this->unattached_section_list_->size();
const int size = parameters->target().get_size();
int shdr_size;
if (size == 32)
shdr_size = elfcpp::Elf_sizes<32>::shdr_size;
else if (size == 64)
shdr_size = elfcpp::Elf_sizes<64>::shdr_size;
else
gold_unreachable();
return count * shdr_size;
}
// Write out the section headers.
void
Output_section_headers::do_write(Output_file* of)
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->do_sized_write<32, false>(of);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->do_sized_write<32, true>(of);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->do_sized_write<64, false>(of);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->do_sized_write<64, true>(of);
break;
#endif
default:
gold_unreachable();
}
}
template<int size, bool big_endian>
void
Output_section_headers::do_sized_write(Output_file* of)
{
off_t all_shdrs_size = this->data_size();
unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size);
const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
unsigned char* v = view;
{
typename elfcpp::Shdr_write<size, big_endian> oshdr(v);
oshdr.put_sh_name(0);
oshdr.put_sh_type(elfcpp::SHT_NULL);
oshdr.put_sh_flags(0);
oshdr.put_sh_addr(0);
oshdr.put_sh_offset(0);
size_t section_count = (this->data_size()
/ elfcpp::Elf_sizes<size>::shdr_size);
if (section_count < elfcpp::SHN_LORESERVE)
oshdr.put_sh_size(0);
else
oshdr.put_sh_size(section_count);
unsigned int shstrndx = this->shstrtab_section_->out_shndx();
if (shstrndx < elfcpp::SHN_LORESERVE)
oshdr.put_sh_link(0);
else
oshdr.put_sh_link(shstrndx);
size_t segment_count = this->segment_list_->size();
oshdr.put_sh_info(segment_count >= elfcpp::PN_XNUM ? segment_count : 0);
oshdr.put_sh_addralign(0);
oshdr.put_sh_entsize(0);
}
v += shdr_size;
unsigned int shndx = 1;
if (!parameters->options().relocatable())
{
for (Layout::Segment_list::const_iterator p =
this->segment_list_->begin();
p != this->segment_list_->end();
++p)
v = (*p)->write_section_headers<size, big_endian>(this->layout_,
this->secnamepool_,
v,
&shndx);
}
else
{
for (Layout::Section_list::const_iterator p =
this->section_list_->begin();
p != this->section_list_->end();
++p)
{
// We do unallocated sections below, except that group
// sections have to come first.
if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
&& (*p)->type() != elfcpp::SHT_GROUP)
continue;
gold_assert(shndx == (*p)->out_shndx());
elfcpp::Shdr_write<size, big_endian> oshdr(v);
(*p)->write_header(this->layout_, this->secnamepool_, &oshdr);
v += shdr_size;
++shndx;
}
}
for (Layout::Section_list::const_iterator p =
this->unattached_section_list_->begin();
p != this->unattached_section_list_->end();
++p)
{
// For a relocatable link, we did unallocated group sections
// above, since they have to come first.
if ((*p)->type() == elfcpp::SHT_GROUP
&& parameters->options().relocatable())
continue;
gold_assert(shndx == (*p)->out_shndx());
elfcpp::Shdr_write<size, big_endian> oshdr(v);
(*p)->write_header(this->layout_, this->secnamepool_, &oshdr);
v += shdr_size;
++shndx;
}
of->write_output_view(this->offset(), all_shdrs_size, view);
}
// Output_segment_header methods.
Output_segment_headers::Output_segment_headers(
const Layout::Segment_list& segment_list)
: segment_list_(segment_list)
{
}
void
Output_segment_headers::do_write(Output_file* of)
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->do_sized_write<32, false>(of);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->do_sized_write<32, true>(of);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->do_sized_write<64, false>(of);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->do_sized_write<64, true>(of);
break;
#endif
default:
gold_unreachable();
}
}
template<int size, bool big_endian>
void
Output_segment_headers::do_sized_write(Output_file* of)
{
const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size;
off_t all_phdrs_size = this->segment_list_.size() * phdr_size;
gold_assert(all_phdrs_size == this->data_size());
unsigned char* view = of->get_output_view(this->offset(),
all_phdrs_size);
unsigned char* v = view;
for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
p != this->segment_list_.end();
++p)
{
elfcpp::Phdr_write<size, big_endian> ophdr(v);
(*p)->write_header(&ophdr);
v += phdr_size;
}
gold_assert(v - view == all_phdrs_size);
of->write_output_view(this->offset(), all_phdrs_size, view);
}
off_t
Output_segment_headers::do_size() const
{
const int size = parameters->target().get_size();
int phdr_size;
if (size == 32)
phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
else if (size == 64)
phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
else
gold_unreachable();
return this->segment_list_.size() * phdr_size;
}
// Output_file_header methods.
Output_file_header::Output_file_header(const Target* target,
const Symbol_table* symtab,
const Output_segment_headers* osh,
const char* entry)
: target_(target),
symtab_(symtab),
segment_header_(osh),
section_header_(NULL),
shstrtab_(NULL),
entry_(entry)
{
this->set_data_size(this->do_size());
}
// Set the section table information for a file header.
void
Output_file_header::set_section_info(const Output_section_headers* shdrs,
const Output_section* shstrtab)
{
this->section_header_ = shdrs;
this->shstrtab_ = shstrtab;
}
// Write out the file header.
void
Output_file_header::do_write(Output_file* of)
{
gold_assert(this->offset() == 0);
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->do_sized_write<32, false>(of);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->do_sized_write<32, true>(of);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->do_sized_write<64, false>(of);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->do_sized_write<64, true>(of);
break;
#endif
default:
gold_unreachable();
}
}
// Write out the file header with appropriate size and endianess.
template<int size, bool big_endian>
void
Output_file_header::do_sized_write(Output_file* of)
{
gold_assert(this->offset() == 0);
int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
unsigned char* view = of->get_output_view(0, ehdr_size);
elfcpp::Ehdr_write<size, big_endian> oehdr(view);
unsigned char e_ident[elfcpp::EI_NIDENT];
memset(e_ident, 0, elfcpp::EI_NIDENT);
e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
if (size == 32)
e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
else if (size == 64)
e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
else
gold_unreachable();
e_ident[elfcpp::EI_DATA] = (big_endian
? elfcpp::ELFDATA2MSB
: elfcpp::ELFDATA2LSB);
e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
oehdr.put_e_ident(e_ident);
elfcpp::ET e_type;
if (parameters->options().relocatable())
e_type = elfcpp::ET_REL;
else if (parameters->options().output_is_position_independent())
e_type = elfcpp::ET_DYN;
else
e_type = elfcpp::ET_EXEC;
oehdr.put_e_type(e_type);
oehdr.put_e_machine(this->target_->machine_code());
oehdr.put_e_version(elfcpp::EV_CURRENT);
oehdr.put_e_entry(this->entry<size>());
if (this->segment_header_ == NULL)
oehdr.put_e_phoff(0);
else
oehdr.put_e_phoff(this->segment_header_->offset());
oehdr.put_e_shoff(this->section_header_->offset());
oehdr.put_e_flags(this->target_->processor_specific_flags());
oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
if (this->segment_header_ == NULL)
{
oehdr.put_e_phentsize(0);
oehdr.put_e_phnum(0);
}
else
{
oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
size_t phnum = (this->segment_header_->data_size()
/ elfcpp::Elf_sizes<size>::phdr_size);
if (phnum > elfcpp::PN_XNUM)
phnum = elfcpp::PN_XNUM;
oehdr.put_e_phnum(phnum);
}
oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
size_t section_count = (this->section_header_->data_size()
/ elfcpp::Elf_sizes<size>::shdr_size);
if (section_count < elfcpp::SHN_LORESERVE)
oehdr.put_e_shnum(this->section_header_->data_size()
/ elfcpp::Elf_sizes<size>::shdr_size);
else
oehdr.put_e_shnum(0);
unsigned int shstrndx = this->shstrtab_->out_shndx();
if (shstrndx < elfcpp::SHN_LORESERVE)
oehdr.put_e_shstrndx(this->shstrtab_->out_shndx());
else
oehdr.put_e_shstrndx(elfcpp::SHN_XINDEX);
// Let the target adjust the ELF header, e.g., to set EI_OSABI in
// the e_ident field.
parameters->target().adjust_elf_header(view, ehdr_size);
of->write_output_view(0, ehdr_size, view);
}
// Return the value to use for the entry address. THIS->ENTRY_ is the
// symbol specified on the command line, if any.
template<int size>
typename elfcpp::Elf_types<size>::Elf_Addr
Output_file_header::entry()
{
const bool should_issue_warning = (this->entry_ != NULL
&& !parameters->options().relocatable()
&& !parameters->options().shared());
// FIXME: Need to support target specific entry symbol.
const char* entry = this->entry_;
if (entry == NULL)
entry = "_start";
Symbol* sym = this->symtab_->lookup(entry);
typename Sized_symbol<size>::Value_type v;
if (sym != NULL)
{
Sized_symbol<size>* ssym;
ssym = this->symtab_->get_sized_symbol<size>(sym);
if (!ssym->is_defined() && should_issue_warning)
gold_warning("entry symbol '%s' exists but is not defined", entry);
v = ssym->value();
}
else
{
// We couldn't find the entry symbol. See if we can parse it as
// a number. This supports, e.g., -e 0x1000.
char* endptr;
v = strtoull(entry, &endptr, 0);
if (*endptr != '\0')
{
if (should_issue_warning)
gold_warning("cannot find entry symbol '%s'", entry);
v = 0;
}
}
return v;
}
// Compute the current data size.
off_t
Output_file_header::do_size() const
{
const int size = parameters->target().get_size();
if (size == 32)
return elfcpp::Elf_sizes<32>::ehdr_size;
else if (size == 64)
return elfcpp::Elf_sizes<64>::ehdr_size;
else
gold_unreachable();
}
// Output_data_const methods.
void
Output_data_const::do_write(Output_file* of)
{
of->write(this->offset(), this->data_.data(), this->data_.size());
}
// Output_data_const_buffer methods.
void
Output_data_const_buffer::do_write(Output_file* of)
{
of->write(this->offset(), this->p_, this->data_size());
}
// Output_section_data methods.
// Record the output section, and set the entry size and such.
void
Output_section_data::set_output_section(Output_section* os)
{
gold_assert(this->output_section_ == NULL);
this->output_section_ = os;
this->do_adjust_output_section(os);
}
// Return the section index of the output section.
unsigned int
Output_section_data::do_out_shndx() const
{
gold_assert(this->output_section_ != NULL);
return this->output_section_->out_shndx();
}
// Set the alignment, which means we may need to update the alignment
// of the output section.
void
Output_section_data::set_addralign(uint64_t addralign)
{
this->addralign_ = addralign;
if (this->output_section_ != NULL
&& this->output_section_->addralign() < addralign)
this->output_section_->set_addralign(addralign);
}
// Output_data_strtab methods.
// Set the final data size.
void
Output_data_strtab::set_final_data_size()
{
this->strtab_->set_string_offsets();
this->set_data_size(this->strtab_->get_strtab_size());
}
// Write out a string table.
void
Output_data_strtab::do_write(Output_file* of)
{
this->strtab_->write(of, this->offset());
}
// Output_reloc methods.
// A reloc against a global symbol.
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
Symbol* gsym,
unsigned int type,
Output_data* od,
Address address,
bool is_relative,
bool is_symbolless)
: address_(address), local_sym_index_(GSYM_CODE), type_(type),
is_relative_(is_relative), is_symbolless_(is_symbolless),
is_section_symbol_(false), shndx_(INVALID_CODE)
{
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.gsym = gsym;
this->u2_.od = od;
if (dynamic)
this->set_needs_dynsym_index();
}
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
Symbol* gsym,
unsigned int type,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx,
Address address,
bool is_relative,
bool is_symbolless)
: address_(address), local_sym_index_(GSYM_CODE), type_(type),
is_relative_(is_relative), is_symbolless_(is_symbolless),
is_section_symbol_(false), shndx_(shndx)
{
gold_assert(shndx != INVALID_CODE);
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.gsym = gsym;
this->u2_.relobj = relobj;
if (dynamic)
this->set_needs_dynsym_index();
}
// A reloc against a local symbol.
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index,
unsigned int type,
Output_data* od,
Address address,
bool is_relative,
bool is_symbolless,
bool is_section_symbol)
: address_(address), local_sym_index_(local_sym_index), type_(type),
is_relative_(is_relative), is_symbolless_(is_symbolless),
is_section_symbol_(is_section_symbol), shndx_(INVALID_CODE)
{
gold_assert(local_sym_index != GSYM_CODE
&& local_sym_index != INVALID_CODE);
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.relobj = relobj;
this->u2_.od = od;
if (dynamic)
this->set_needs_dynsym_index();
}
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index,
unsigned int type,
unsigned int shndx,
Address address,
bool is_relative,
bool is_symbolless,
bool is_section_symbol)
: address_(address), local_sym_index_(local_sym_index), type_(type),
is_relative_(is_relative), is_symbolless_(is_symbolless),
is_section_symbol_(is_section_symbol), shndx_(shndx)
{
gold_assert(local_sym_index != GSYM_CODE
&& local_sym_index != INVALID_CODE);
gold_assert(shndx != INVALID_CODE);
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.relobj = relobj;
this->u2_.relobj = relobj;
if (dynamic)
this->set_needs_dynsym_index();
}
// A reloc against the STT_SECTION symbol of an output section.
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
Output_section* os,
unsigned int type,
Output_data* od,
Address address)
: address_(address), local_sym_index_(SECTION_CODE), type_(type),
is_relative_(false), is_symbolless_(false),
is_section_symbol_(true), shndx_(INVALID_CODE)
{
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.os = os;
this->u2_.od = od;
if (dynamic)
this->set_needs_dynsym_index();
else
os->set_needs_symtab_index();
}
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
Output_section* os,
unsigned int type,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx,
Address address)
: address_(address), local_sym_index_(SECTION_CODE), type_(type),
is_relative_(false), is_symbolless_(false),
is_section_symbol_(true), shndx_(shndx)
{
gold_assert(shndx != INVALID_CODE);
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.os = os;
this->u2_.relobj = relobj;
if (dynamic)
this->set_needs_dynsym_index();
else
os->set_needs_symtab_index();
}
// An absolute relocation.
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
unsigned int type,
Output_data* od,
Address address)
: address_(address), local_sym_index_(0), type_(type),
is_relative_(false), is_symbolless_(false),
is_section_symbol_(false), shndx_(INVALID_CODE)
{
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.relobj = NULL;
this->u2_.od = od;
}
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
unsigned int type,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx,
Address address)
: address_(address), local_sym_index_(0), type_(type),
is_relative_(false), is_symbolless_(false),
is_section_symbol_(false), shndx_(shndx)
{
gold_assert(shndx != INVALID_CODE);
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.relobj = NULL;
this->u2_.relobj = relobj;
}
// A target specific relocation.
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
unsigned int type,
void* arg,
Output_data* od,
Address address)
: address_(address), local_sym_index_(TARGET_CODE), type_(type),
is_relative_(false), is_symbolless_(false),
is_section_symbol_(false), shndx_(INVALID_CODE)
{
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.arg = arg;
this->u2_.od = od;
}
template<bool dynamic, int size, bool big_endian>
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
unsigned int type,
void* arg,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx,
Address address)
: address_(address), local_sym_index_(TARGET_CODE), type_(type),
is_relative_(false), is_symbolless_(false),
is_section_symbol_(false), shndx_(shndx)
{
gold_assert(shndx != INVALID_CODE);
// this->type_ is a bitfield; make sure TYPE fits.
gold_assert(this->type_ == type);
this->u1_.arg = arg;
this->u2_.relobj = relobj;
}
// Record that we need a dynamic symbol index for this relocation.
template<bool dynamic, int size, bool big_endian>
void
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::
set_needs_dynsym_index()
{
if (this->is_symbolless_)
return;
switch (this->local_sym_index_)
{
case INVALID_CODE:
gold_unreachable();
case GSYM_CODE:
this->u1_.gsym->set_needs_dynsym_entry();
break;
case SECTION_CODE:
this->u1_.os->set_needs_dynsym_index();
break;
case TARGET_CODE:
// The target must take care of this if necessary.
break;
case 0:
break;
default:
{
const unsigned int lsi = this->local_sym_index_;
if (!this->is_section_symbol_)
this->u1_.relobj->set_needs_output_dynsym_entry(lsi);
else
this->u1_.relobj->output_section(lsi)->set_needs_dynsym_index();
}
break;
}
}
// Get the symbol index of a relocation.
template<bool dynamic, int size, bool big_endian>
unsigned int
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
const
{
unsigned int index;
if (this->is_symbolless_)
return 0;
switch (this->local_sym_index_)
{
case INVALID_CODE:
gold_unreachable();
case GSYM_CODE:
if (this->u1_.gsym == NULL)
index = 0;
else if (dynamic)
index = this->u1_.gsym->dynsym_index();
else
index = this->u1_.gsym->symtab_index();
break;
case SECTION_CODE:
if (dynamic)
index = this->u1_.os->dynsym_index();
else
index = this->u1_.os->symtab_index();
break;
case TARGET_CODE:
index = parameters->target().reloc_symbol_index(this->u1_.arg,
this->type_);
break;
case 0:
// Relocations without symbols use a symbol index of 0.
index = 0;
break;
default:
{
const unsigned int lsi = this->local_sym_index_;
if (!this->is_section_symbol_)
{
if (dynamic)
index = this->u1_.relobj->dynsym_index(lsi);
else
index = this->u1_.relobj->symtab_index(lsi);
}
else
{
Output_section* os = this->u1_.relobj->output_section(lsi);
gold_assert(os != NULL);
if (dynamic)
index = os->dynsym_index();
else
index = os->symtab_index();
}
}
break;
}
gold_assert(index != -1U);
return index;
}
// For a local section symbol, get the address of the offset ADDEND
// within the input section.
template<bool dynamic, int size, bool big_endian>
typename elfcpp::Elf_types<size>::Elf_Addr
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::
local_section_offset(Addend addend) const
{
gold_assert(this->local_sym_index_ != GSYM_CODE
&& this->local_sym_index_ != SECTION_CODE
&& this->local_sym_index_ != TARGET_CODE
&& this->local_sym_index_ != INVALID_CODE
&& this->local_sym_index_ != 0
&& this->is_section_symbol_);
const unsigned int lsi = this->local_sym_index_;
Output_section* os = this->u1_.relobj->output_section(lsi);
gold_assert(os != NULL);
Address offset = this->u1_.relobj->get_output_section_offset(lsi);
if (offset != invalid_address)
return offset + addend;
// This is a merge section.
offset = os->output_address(this->u1_.relobj, lsi, addend);
gold_assert(offset != invalid_address);
return offset;
}
// Get the output address of a relocation.
template<bool dynamic, int size, bool big_endian>
typename elfcpp::Elf_types<size>::Elf_Addr
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_address() const
{
Address address = this->address_;
if (this->shndx_ != INVALID_CODE)
{
Output_section* os = this->u2_.relobj->output_section(this->shndx_);
gold_assert(os != NULL);
Address off = this->u2_.relobj->get_output_section_offset(this->shndx_);
if (off != invalid_address)
address += os->address() + off;
else
{
address = os->output_address(this->u2_.relobj, this->shndx_,
address);
gold_assert(address != invalid_address);
}
}
else if (this->u2_.od != NULL)
address += this->u2_.od->address();
return address;
}
// Write out the offset and info fields of a Rel or Rela relocation
// entry.
template<bool dynamic, int size, bool big_endian>
template<typename Write_rel>
void
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write_rel(
Write_rel* wr) const
{
wr->put_r_offset(this->get_address());
unsigned int sym_index = this->get_symbol_index();
wr->put_r_info(elfcpp::elf_r_info<size>(sym_index, this->type_));
}
// Write out a Rel relocation.
template<bool dynamic, int size, bool big_endian>
void
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write(
unsigned char* pov) const
{
elfcpp::Rel_write<size, big_endian> orel(pov);
this->write_rel(&orel);
}
// Get the value of the symbol referred to by a Rel relocation.
template<bool dynamic, int size, bool big_endian>
typename elfcpp::Elf_types<size>::Elf_Addr
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::symbol_value(
Addend addend) const
{
if (this->local_sym_index_ == GSYM_CODE)
{
const Sized_symbol<size>* sym;
sym = static_cast<const Sized_symbol<size>*>(this->u1_.gsym);
return sym->value() + addend;
}
gold_assert(this->local_sym_index_ != SECTION_CODE
&& this->local_sym_index_ != TARGET_CODE
&& this->local_sym_index_ != INVALID_CODE
&& this->local_sym_index_ != 0
&& !this->is_section_symbol_);
const unsigned int lsi = this->local_sym_index_;
const Symbol_value<size>* symval = this->u1_.relobj->local_symbol(lsi);
return symval->value(this->u1_.relobj, addend);
}
// Reloc comparison. This function sorts the dynamic relocs for the
// benefit of the dynamic linker. First we sort all relative relocs
// to the front. Among relative relocs, we sort by output address.
// Among non-relative relocs, we sort by symbol index, then by output
// address.
template<bool dynamic, int size, bool big_endian>
int
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::
compare(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>& r2)
const
{
if (this->is_relative_)
{
if (!r2.is_relative_)
return -1;
// Otherwise sort by reloc address below.
}
else if (r2.is_relative_)
return 1;
else
{
unsigned int sym1 = this->get_symbol_index();
unsigned int sym2 = r2.get_symbol_index();
if (sym1 < sym2)
return -1;
else if (sym1 > sym2)
return 1;
// Otherwise sort by reloc address.
}
section_offset_type addr1 = this->get_address();
section_offset_type addr2 = r2.get_address();
if (addr1 < addr2)
return -1;
else if (addr1 > addr2)
return 1;
// Final tie breaker, in order to generate the same output on any
// host: reloc type.
unsigned int type1 = this->type_;
unsigned int type2 = r2.type_;
if (type1 < type2)
return -1;
else if (type1 > type2)
return 1;
// These relocs appear to be exactly the same.
return 0;
}
// Write out a Rela relocation.
template<bool dynamic, int size, bool big_endian>
void
Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>::write(
unsigned char* pov) const
{
elfcpp::Rela_write<size, big_endian> orel(pov);
this->rel_.write_rel(&orel);
Addend addend = this->addend_;
if (this->rel_.is_target_specific())
addend = parameters->target().reloc_addend(this->rel_.target_arg(),
this->rel_.type(), addend);
else if (this->rel_.is_symbolless())
addend = this->rel_.symbol_value(addend);
else if (this->rel_.is_local_section_symbol())
addend = this->rel_.local_section_offset(addend);
orel.put_r_addend(addend);
}
// Output_data_reloc_base methods.
// Adjust the output section.
template<int sh_type, bool dynamic, int size, bool big_endian>
void
Output_data_reloc_base<sh_type, dynamic, size, big_endian>
::do_adjust_output_section(Output_section* os)
{
if (sh_type == elfcpp::SHT_REL)
os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
else if (sh_type == elfcpp::SHT_RELA)
os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
else
gold_unreachable();
if (dynamic)
os->set_should_link_to_dynsym();
else
os->set_should_link_to_symtab();
}
// Write out relocation data.
template<int sh_type, bool dynamic, int size, bool big_endian>
void
Output_data_reloc_base<sh_type, dynamic, size, big_endian>::do_write(
Output_file* of)
{
const off_t off = this->offset();
const off_t oview_size = this->data_size();
unsigned char* const oview = of->get_output_view(off, oview_size);
if (this->sort_relocs())
{
gold_assert(dynamic);
std::sort(this->relocs_.begin(), this->relocs_.end(),
Sort_relocs_comparison());
}
unsigned char* pov = oview;
for (typename Relocs::const_iterator p = this->relocs_.begin();
p != this->relocs_.end();
++p)
{
p->write(pov);
pov += reloc_size;
}
gold_assert(pov - oview == oview_size);
of->write_output_view(off, oview_size, oview);
// We no longer need the relocation entries.
this->relocs_.clear();
}
// Class Output_relocatable_relocs.
template<int sh_type, int size, bool big_endian>
void
Output_relocatable_relocs<sh_type, size, big_endian>::set_final_data_size()
{
this->set_data_size(this->rr_->output_reloc_count()
* Reloc_types<sh_type, size, big_endian>::reloc_size);
}
// class Output_data_group.
template<int size, bool big_endian>
Output_data_group<size, big_endian>::Output_data_group(
Sized_relobj<size, big_endian>* relobj,
section_size_type entry_count,
elfcpp::Elf_Word flags,
std::vector<unsigned int>* input_shndxes)
: Output_section_data(entry_count * 4, 4, false),
relobj_(relobj),
flags_(flags)
{
this->input_shndxes_.swap(*input_shndxes);
}
// Write out the section group, which means translating the section
// indexes to apply to the output file.
template<int size, bool big_endian>
void
Output_data_group<size, big_endian>::do_write(Output_file* of)
{
const off_t off = this->offset();
const section_size_type oview_size =
convert_to_section_size_type(this->data_size());
unsigned char* const oview = of->get_output_view(off, oview_size);
elfcpp::Elf_Word* contents = reinterpret_cast<elfcpp::Elf_Word*>(oview);
elfcpp::Swap<32, big_endian>::writeval(contents, this->flags_);
++contents;
for (std::vector<unsigned int>::const_iterator p =
this->input_shndxes_.begin();
p != this->input_shndxes_.end();
++p, ++contents)
{
Output_section* os = this->relobj_->output_section(*p);
unsigned int output_shndx;
if (os != NULL)
output_shndx = os->out_shndx();
else
{
this->relobj_->error(_("section group retained but "
"group element discarded"));
output_shndx = 0;
}
elfcpp::Swap<32, big_endian>::writeval(contents, output_shndx);
}
size_t wrote = reinterpret_cast<unsigned char*>(contents) - oview;
gold_assert(wrote == oview_size);
of->write_output_view(off, oview_size, oview);
// We no longer need this information.
this->input_shndxes_.clear();
}
// Output_data_got::Got_entry methods.
// Write out the entry.
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const
{
Valtype val = 0;
switch (this->local_sym_index_)
{
case GSYM_CODE:
{
// If the symbol is resolved locally, we need to write out the
// link-time value, which will be relocated dynamically by a
// RELATIVE relocation.
Symbol* gsym = this->u_.gsym;
Sized_symbol<size>* sgsym;
// This cast is a bit ugly. We don't want to put a
// virtual method in Symbol, because we want Symbol to be
// as small as possible.
sgsym = static_cast<Sized_symbol<size>*>(gsym);
val = sgsym->value();
}
break;
case CONSTANT_CODE:
val = this->u_.constant;
break;
default:
{
const unsigned int lsi = this->local_sym_index_;
const Symbol_value<size>* symval = this->u_.object->local_symbol(lsi);
val = symval->value(this->u_.object, 0);
}
break;
}
elfcpp::Swap<size, big_endian>::writeval(pov, val);
}
// Output_data_got methods.
// Add an entry for a global symbol to the GOT. This returns true if
// this is a new GOT entry, false if the symbol already had a GOT
// entry.
template<int size, bool big_endian>
bool
Output_data_got<size, big_endian>::add_global(
Symbol* gsym,
unsigned int got_type)
{
if (gsym->has_got_offset(got_type))
return false;
this->entries_.push_back(Got_entry(gsym));
this->set_got_size();
gsym->set_got_offset(got_type, this->last_got_offset());
return true;
}
// Add an entry for a global symbol to the GOT, and add a dynamic
// relocation of type R_TYPE for the GOT entry.
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_global_with_rel(
Symbol* gsym,
unsigned int got_type,
Rel_dyn* rel_dyn,
unsigned int r_type)
{
if (gsym->has_got_offset(got_type))
return;
this->entries_.push_back(Got_entry());
this->set_got_size();
unsigned int got_offset = this->last_got_offset();
gsym->set_got_offset(got_type, got_offset);
rel_dyn->add_global(gsym, r_type, this, got_offset);
}
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_global_with_rela(
Symbol* gsym,
unsigned int got_type,
Rela_dyn* rela_dyn,
unsigned int r_type)
{
if (gsym->has_got_offset(got_type))
return;
this->entries_.push_back(Got_entry());
this->set_got_size();
unsigned int got_offset = this->last_got_offset();
gsym->set_got_offset(got_type, got_offset);
rela_dyn->add_global(gsym, r_type, this, got_offset, 0);
}
// Add a pair of entries for a global symbol to the GOT, and add
// dynamic relocations of type R_TYPE_1 and R_TYPE_2, respectively.
// If R_TYPE_2 == 0, add the second entry with no relocation.
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_global_pair_with_rel(
Symbol* gsym,
unsigned int got_type,
Rel_dyn* rel_dyn,
unsigned int r_type_1,
unsigned int r_type_2)
{
if (gsym->has_got_offset(got_type))
return;
this->entries_.push_back(Got_entry());
unsigned int got_offset = this->last_got_offset();
gsym->set_got_offset(got_type, got_offset);
rel_dyn->add_global(gsym, r_type_1, this, got_offset);
this->entries_.push_back(Got_entry());
if (r_type_2 != 0)
{
got_offset = this->last_got_offset();
rel_dyn->add_global(gsym, r_type_2, this, got_offset);
}
this->set_got_size();
}
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_global_pair_with_rela(
Symbol* gsym,
unsigned int got_type,
Rela_dyn* rela_dyn,
unsigned int r_type_1,
unsigned int r_type_2)
{
if (gsym->has_got_offset(got_type))
return;
this->entries_.push_back(Got_entry());
unsigned int got_offset = this->last_got_offset();
gsym->set_got_offset(got_type, got_offset);
rela_dyn->add_global(gsym, r_type_1, this, got_offset, 0);
this->entries_.push_back(Got_entry());
if (r_type_2 != 0)
{
got_offset = this->last_got_offset();
rela_dyn->add_global(gsym, r_type_2, this, got_offset, 0);
}
this->set_got_size();
}
// Add an entry for a local symbol to the GOT. This returns true if
// this is a new GOT entry, false if the symbol already has a GOT
// entry.
template<int size, bool big_endian>
bool
Output_data_got<size, big_endian>::add_local(
Sized_relobj<size, big_endian>* object,
unsigned int symndx,
unsigned int got_type)
{
if (object->local_has_got_offset(symndx, got_type))
return false;
this->entries_.push_back(Got_entry(object, symndx));
this->set_got_size();
object->set_local_got_offset(symndx, got_type, this->last_got_offset());
return true;
}
// Add an entry for a local symbol to the GOT, and add a dynamic
// relocation of type R_TYPE for the GOT entry.
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_local_with_rel(
Sized_relobj<size, big_endian>* object,
unsigned int symndx,
unsigned int got_type,
Rel_dyn* rel_dyn,
unsigned int r_type)
{
if (object->local_has_got_offset(symndx, got_type))
return;
this->entries_.push_back(Got_entry());
this->set_got_size();
unsigned int got_offset = this->last_got_offset();
object->set_local_got_offset(symndx, got_type, got_offset);
rel_dyn->add_local(object, symndx, r_type, this, got_offset);
}
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_local_with_rela(
Sized_relobj<size, big_endian>* object,
unsigned int symndx,
unsigned int got_type,
Rela_dyn* rela_dyn,
unsigned int r_type)
{
if (object->local_has_got_offset(symndx, got_type))
return;
this->entries_.push_back(Got_entry());
this->set_got_size();
unsigned int got_offset = this->last_got_offset();
object->set_local_got_offset(symndx, got_type, got_offset);
rela_dyn->add_local(object, symndx, r_type, this, got_offset, 0);
}
// Add a pair of entries for a local symbol to the GOT, and add
// dynamic relocations of type R_TYPE_1 and R_TYPE_2, respectively.
// If R_TYPE_2 == 0, add the second entry with no relocation.
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_local_pair_with_rel(
Sized_relobj<size, big_endian>* object,
unsigned int symndx,
unsigned int shndx,
unsigned int got_type,
Rel_dyn* rel_dyn,
unsigned int r_type_1,
unsigned int r_type_2)
{
if (object->local_has_got_offset(symndx, got_type))
return;
this->entries_.push_back(Got_entry());
unsigned int got_offset = this->last_got_offset();
object->set_local_got_offset(symndx, got_type, got_offset);
Output_section* os = object->output_section(shndx);
rel_dyn->add_output_section(os, r_type_1, this, got_offset);
this->entries_.push_back(Got_entry(object, symndx));
if (r_type_2 != 0)
{
got_offset = this->last_got_offset();
rel_dyn->add_output_section(os, r_type_2, this, got_offset);
}
this->set_got_size();
}
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::add_local_pair_with_rela(
Sized_relobj<size, big_endian>* object,
unsigned int symndx,
unsigned int shndx,
unsigned int got_type,
Rela_dyn* rela_dyn,
unsigned int r_type_1,
unsigned int r_type_2)
{
if (object->local_has_got_offset(symndx, got_type))
return;
this->entries_.push_back(Got_entry());
unsigned int got_offset = this->last_got_offset();
object->set_local_got_offset(symndx, got_type, got_offset);
Output_section* os = object->output_section(shndx);
rela_dyn->add_output_section(os, r_type_1, this, got_offset, 0);
this->entries_.push_back(Got_entry(object, symndx));
if (r_type_2 != 0)
{
got_offset = this->last_got_offset();
rela_dyn->add_output_section(os, r_type_2, this, got_offset, 0);
}
this->set_got_size();
}
// Write out the GOT.
template<int size, bool big_endian>
void
Output_data_got<size, big_endian>::do_write(Output_file* of)
{
const int add = size / 8;
const off_t off = this->offset();
const off_t oview_size = this->data_size();
unsigned char* const oview = of->get_output_view(off, oview_size);
unsigned char* pov = oview;
for (typename Got_entries::const_iterator p = this->entries_.begin();
p != this->entries_.end();
++p)
{
p->write(pov);
pov += add;
}
gold_assert(pov - oview == oview_size);
of->write_output_view(off, oview_size, oview);
// We no longer need the GOT entries.
this->entries_.clear();
}
// Output_data_dynamic::Dynamic_entry methods.
// Write out the entry.
template<int size, bool big_endian>
void
Output_data_dynamic::Dynamic_entry::write(
unsigned char* pov,
const Stringpool* pool) const
{
typename elfcpp::Elf_types<size>::Elf_WXword val;
switch (this->offset_)
{
case DYNAMIC_NUMBER:
val = this->u_.val;
break;
case DYNAMIC_SECTION_SIZE:
val = this->u_.od->data_size();
if (this->od2 != NULL)
val += this->od2->data_size();
break;
case DYNAMIC_SYMBOL:
{
const Sized_symbol<size>* s =
static_cast<const Sized_symbol<size>*>(this->u_.sym);
val = s->value();
}
break;
case DYNAMIC_STRING:
val = pool->get_offset(this->u_.str);
break;
default:
val = this->u_.od->address() + this->offset_;
break;
}
elfcpp::Dyn_write<size, big_endian> dw(pov);
dw.put_d_tag(this->tag_);
dw.put_d_val(val);
}
// Output_data_dynamic methods.
// Adjust the output section to set the entry size.
void
Output_data_dynamic::do_adjust_output_section(Output_section* os)
{
if (parameters->target().get_size() == 32)
os->set_entsize(elfcpp::Elf_sizes<32>::dyn_size);
else if (parameters->target().get_size() == 64)
os->set_entsize(elfcpp::Elf_sizes<64>::dyn_size);
else
gold_unreachable();
}
// Set the final data size.
void
Output_data_dynamic::set_final_data_size()
{
// Add the terminating entry if it hasn't been added.
// Because of relaxation, we can run this multiple times.
if (this->entries_.empty() || this->entries_.back().tag() != elfcpp::DT_NULL)
{
int extra = parameters->options().spare_dynamic_tags();
for (int i = 0; i < extra; ++i)
this->add_constant(elfcpp::DT_NULL, 0);
this->add_constant(elfcpp::DT_NULL, 0);
}
int dyn_size;
if (parameters->target().get_size() == 32)
dyn_size = elfcpp::Elf_sizes<32>::dyn_size;
else if (parameters->target().get_size() == 64)
dyn_size = elfcpp::Elf_sizes<64>::dyn_size;
else
gold_unreachable();
this->set_data_size(this->entries_.size() * dyn_size);
}
// Write out the dynamic entries.
void
Output_data_dynamic::do_write(Output_file* of)
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->sized_write<32, false>(of);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->sized_write<32, true>(of);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->sized_write<64, false>(of);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->sized_write<64, true>(of);
break;
#endif
default:
gold_unreachable();
}
}
template<int size, bool big_endian>
void
Output_data_dynamic::sized_write(Output_file* of)
{
const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
const off_t offset = this->offset();
const off_t oview_size = this->data_size();
unsigned char* const oview = of->get_output_view(offset, oview_size);
unsigned char* pov = oview;
for (typename Dynamic_entries::const_iterator p = this->entries_.begin();
p != this->entries_.end();
++p)
{
p->write<size, big_endian>(pov, this->pool_);
pov += dyn_size;
}
gold_assert(pov - oview == oview_size);
of->write_output_view(offset, oview_size, oview);
// We no longer need the dynamic entries.
this->entries_.clear();
}
// Class Output_symtab_xindex.
void
Output_symtab_xindex::do_write(Output_file* of)
{
const off_t offset = this->offset();
const off_t oview_size = this->data_size();
unsigned char* const oview = of->get_output_view(offset, oview_size);
memset(oview, 0, oview_size);
if (parameters->target().is_big_endian())
this->endian_do_write<true>(oview);
else
this->endian_do_write<false>(oview);
of->write_output_view(offset, oview_size, oview);
// We no longer need the data.
this->entries_.clear();
}
template<bool big_endian>
void
Output_symtab_xindex::endian_do_write(unsigned char* const oview)
{
for (Xindex_entries::const_iterator p = this->entries_.begin();
p != this->entries_.end();
++p)
{
unsigned int symndx = p->first;
gold_assert(symndx * 4 < this->data_size());
elfcpp::Swap<32, big_endian>::writeval(oview + symndx * 4, p->second);
}
}
// Output_section::Input_section methods.
// Return the data size. For an input section we store the size here.
// For an Output_section_data, we have to ask it for the size.
off_t
Output_section::Input_section::data_size() const
{
if (this->is_input_section())
return this->u1_.data_size;
else
return this->u2_.posd->data_size();
}
// Return the object for an input section.
Relobj*
Output_section::Input_section::relobj() const
{
if (this->is_input_section())
return this->u2_.object;
else if (this->is_merge_section())
{
gold_assert(this->u2_.pomb->first_relobj() != NULL);
return this->u2_.pomb->first_relobj();
}
else if (this->is_relaxed_input_section())
return this->u2_.poris->relobj();
else
gold_unreachable();
}
// Return the input section index for an input section.
unsigned int
Output_section::Input_section::shndx() const
{
if (this->is_input_section())
return this->shndx_;
else if (this->is_merge_section())
{
gold_assert(this->u2_.pomb->first_relobj() != NULL);
return this->u2_.pomb->first_shndx();
}
else if (this->is_relaxed_input_section())
return this->u2_.poris->shndx();
else
gold_unreachable();
}
// Set the address and file offset.
void
Output_section::Input_section::set_address_and_file_offset(
uint64_t address,
off_t file_offset,
off_t section_file_offset)
{
if (this->is_input_section())
this->u2_.object->set_section_offset(this->shndx_,
file_offset - section_file_offset);
else
this->u2_.posd->set_address_and_file_offset(address, file_offset);
}
// Reset the address and file offset.
void
Output_section::Input_section::reset_address_and_file_offset()
{
if (!this->is_input_section())
this->u2_.posd->reset_address_and_file_offset();
}
// Finalize the data size.
void
Output_section::Input_section::finalize_data_size()
{
if (!this->is_input_section())
this->u2_.posd->finalize_data_size();
}
// Try to turn an input offset into an output offset. We want to
// return the output offset relative to the start of this
// Input_section in the output section.
inline bool
Output_section::Input_section::output_offset(
const Relobj* object,
unsigned int shndx,
section_offset_type offset,
section_offset_type *poutput) const
{
if (!this->is_input_section())
return this->u2_.posd->output_offset(object, shndx, offset, poutput);
else
{
if (this->shndx_ != shndx || this->u2_.object != object)
return false;
*poutput = offset;
return true;
}
}
// Return whether this is the merge section for the input section
// SHNDX in OBJECT.
inline bool
Output_section::Input_section::is_merge_section_for(const Relobj* object,
unsigned int shndx) const
{
if (this->is_input_section())
return false;
return this->u2_.posd->is_merge_section_for(object, shndx);
}
// Write out the data. We don't have to do anything for an input
// section--they are handled via Object::relocate--but this is where
// we write out the data for an Output_section_data.
void
Output_section::Input_section::write(Output_file* of)
{
if (!this->is_input_section())
this->u2_.posd->write(of);
}
// Write the data to a buffer. As for write(), we don't have to do
// anything for an input section.
void
Output_section::Input_section::write_to_buffer(unsigned char* buffer)
{
if (!this->is_input_section())
this->u2_.posd->write_to_buffer(buffer);
}
// Print to a map file.
void
Output_section::Input_section::print_to_mapfile(Mapfile* mapfile) const
{
switch (this->shndx_)
{
case OUTPUT_SECTION_CODE:
case MERGE_DATA_SECTION_CODE:
case MERGE_STRING_SECTION_CODE:
this->u2_.posd->print_to_mapfile(mapfile);
break;
case RELAXED_INPUT_SECTION_CODE:
{
Output_relaxed_input_section* relaxed_section =
this->relaxed_input_section();
mapfile->print_input_section(relaxed_section->relobj(),
relaxed_section->shndx());
}
break;
default:
mapfile->print_input_section(this->u2_.object, this->shndx_);
break;
}
}
// Output_section methods.
// Construct an Output_section. NAME will point into a Stringpool.
Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags)
: name_(name),
addralign_(0),
entsize_(0),
load_address_(0),
link_section_(NULL),
link_(0),
info_section_(NULL),
info_symndx_(NULL),
info_(0),
type_(type),
flags_(flags),
out_shndx_(-1U),
symtab_index_(0),
dynsym_index_(0),
input_sections_(),
first_input_offset_(0),
fills_(),
postprocessing_buffer_(NULL),
needs_symtab_index_(false),
needs_dynsym_index_(false),
should_link_to_symtab_(false),
should_link_to_dynsym_(false),
after_input_sections_(false),
requires_postprocessing_(false),
found_in_sections_clause_(false),
has_load_address_(false),
info_uses_section_index_(false),
input_section_order_specified_(false),
may_sort_attached_input_sections_(false),
must_sort_attached_input_sections_(false),
attached_input_sections_are_sorted_(false),
is_relro_(false),
is_relro_local_(false),
is_last_relro_(false),
is_first_non_relro_(false),
is_small_section_(false),
is_large_section_(false),
is_interp_(false),
is_dynamic_linker_section_(false),
generate_code_fills_at_write_(false),
is_entsize_zero_(false),
section_offsets_need_adjustment_(false),
is_noload_(false),
always_keeps_input_sections_(false),
tls_offset_(0),
checkpoint_(NULL),
lookup_maps_(new Output_section_lookup_maps)
{
// An unallocated section has no address. Forcing this means that
// we don't need special treatment for symbols defined in debug
// sections.
if ((flags & elfcpp::SHF_ALLOC) == 0)
this->set_address(0);
}
Output_section::~Output_section()
{
delete this->checkpoint_;
}
// Set the entry size.
void
Output_section::set_entsize(uint64_t v)
{
if (this->is_entsize_zero_)
;
else if (this->entsize_ == 0)
this->entsize_ = v;
else if (this->entsize_ != v)
{
this->entsize_ = 0;
this->is_entsize_zero_ = 1;
}
}
// Add the input section SHNDX, with header SHDR, named SECNAME, in
// OBJECT, to the Output_section. RELOC_SHNDX is the index of a
// relocation section which applies to this section, or 0 if none, or
// -1U if more than one. Return the offset of the input section
// within the output section. Return -1 if the input section will
// receive special handling. In the normal case we don't always keep
// track of input sections for an Output_section. Instead, each
// Object keeps track of the Output_section for each of its input
// sections. However, if HAVE_SECTIONS_SCRIPT is true, we do keep
// track of input sections here; this is used when SECTIONS appears in
// a linker script.
template<int size, bool big_endian>
off_t
Output_section::add_input_section(Layout* layout,
Sized_relobj<size, big_endian>* object,
unsigned int shndx,
const char* secname,
const elfcpp::Shdr<size, big_endian>& shdr,
unsigned int reloc_shndx,
bool have_sections_script)
{
elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
if ((addralign & (addralign - 1)) != 0)
{
object->error(_("invalid alignment %lu for section \"%s\""),
static_cast<unsigned long>(addralign), secname);
addralign = 1;
}
if (addralign > this->addralign_)
this->addralign_ = addralign;
typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
uint64_t entsize = shdr.get_sh_entsize();
// .debug_str is a mergeable string section, but is not always so
// marked by compilers. Mark manually here so we can optimize.
if (strcmp(secname, ".debug_str") == 0)
{
sh_flags |= (elfcpp::SHF_MERGE | elfcpp::SHF_STRINGS);
entsize = 1;
}
this->update_flags_for_input_section(sh_flags);
this->set_entsize(entsize);
// If this is a SHF_MERGE section, we pass all the input sections to
// a Output_data_merge. We don't try to handle relocations for such
// a section. We don't try to handle empty merge sections--they
// mess up the mappings, and are useless anyhow.
if ((sh_flags & elfcpp::SHF_MERGE) != 0
&& reloc_shndx == 0
&& shdr.get_sh_size() > 0)
{
// Keep information about merged input sections for rebuilding fast
// lookup maps if we have sections-script or we do relaxation.
bool keeps_input_sections = (this->always_keeps_input_sections_
|| have_sections_script
|| parameters->target().may_relax());
if (this->add_merge_input_section(object, shndx, sh_flags, entsize,
addralign, keeps_input_sections))
{
// Tell the relocation routines that they need to call the
// output_offset method to determine the final address.
return -1;
}
}
off_t offset_in_section = this->current_data_size_for_child();
off_t aligned_offset_in_section = align_address(offset_in_section,
addralign);
// Determine if we want to delay code-fill generation until the output
// section is written. When the target is relaxing, we want to delay fill
// generating to avoid adjusting them during relaxation.
if (!this->generate_code_fills_at_write_
&& !have_sections_script
&& (sh_flags & elfcpp::SHF_EXECINSTR) != 0
&& parameters->target().has_code_fill()
&& parameters->target().may_relax())
{
gold_assert(this->fills_.empty());
this->generate_code_fills_at_write_ = true;
}
if (aligned_offset_in_section > offset_in_section
&& !this->generate_code_fills_at_write_
&& !have_sections_script
&& (sh_flags & elfcpp::SHF_EXECINSTR) != 0
&& parameters->target().has_code_fill())
{
// We need to add some fill data. Using fill_list_ when
// possible is an optimization, since we will often have fill
// sections without input sections.
off_t fill_len = aligned_offset_in_section - offset_in_section;
if (this->input_sections_.empty())
this->fills_.push_back(Fill(offset_in_section, fill_len));
else
{
std::string fill_data(parameters->target().code_fill(fill_len));
Output_data_const* odc = new Output_data_const(fill_data, 1);
this->input_sections_.push_back(Input_section(odc));
}
}
section_size_type input_section_size = shdr.get_sh_size();
section_size_type uncompressed_size;
if (object->section_is_compressed(shndx, &uncompressed_size))
input_section_size = uncompressed_size;
this->set_current_data_size_for_child(aligned_offset_in_section
+ input_section_size);
// We need to keep track of this section if we are already keeping
// track of sections, or if we are relaxing. Also, if this is a
// section which requires sorting, or which may require sorting in
// the future, we keep track of the sections. If the
// --section-ordering-file option is used to specify the order of
// sections, we need to keep track of sections.
if (this->always_keeps_input_sections_
|| have_sections_script
|| !this->input_sections_.empty()
|| this->may_sort_attached_input_sections()
|| this->must_sort_attached_input_sections()
|| parameters->options().user_set_Map()
|| parameters->target().may_relax()
|| parameters->options().section_ordering_file())
{
Input_section isecn(object, shndx, shdr.get_sh_size(), addralign);
if (parameters->options().section_ordering_file())
{
unsigned int section_order_index =
layout->find_section_order_index(std::string(secname));
if (section_order_index != 0)
{
isecn.set_section_order_index(section_order_index);
this->set_input_section_order_specified();
}
}
this->input_sections_.push_back(isecn);
}
return aligned_offset_in_section;
}
// Add arbitrary data to an output section.
void
Output_section::add_output_section_data(Output_section_data* posd)
{
Input_section inp(posd);
this->add_output_section_data(&inp);
if (posd->is_data_size_valid())
{
off_t offset_in_section = this->current_data_size_for_child();
off_t aligned_offset_in_section = align_address(offset_in_section,
posd->addralign());
this->set_current_data_size_for_child(aligned_offset_in_section
+ posd->data_size());
}
}
// Add a relaxed input section.
void
Output_section::add_relaxed_input_section(Output_relaxed_input_section* poris)
{
Input_section inp(poris);
this->add_output_section_data(&inp);
if (this->lookup_maps_->is_valid())
this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
poris->shndx(), poris);
// For a relaxed section, we use the current data size. Linker scripts
// get all the input sections, including relaxed one from an output
// section and add them back to them same output section to compute the
// output section size. If we do not account for sizes of relaxed input
// sections, an output section would be incorrectly sized.
off_t offset_in_section = this->current_data_size_for_child();
off_t aligned_offset_in_section = align_address(offset_in_section,
poris->addralign());
this->set_current_data_size_for_child(aligned_offset_in_section
+ poris->current_data_size());
}
// Add arbitrary data to an output section by Input_section.
void
Output_section::add_output_section_data(Input_section* inp)
{
if (this->input_sections_.empty())
this->first_input_offset_ = this->current_data_size_for_child();
this->input_sections_.push_back(*inp);
uint64_t addralign = inp->addralign();
if (addralign > this->addralign_)
this->addralign_ = addralign;
inp->set_output_section(this);
}
// Add a merge section to an output section.
void
Output_section::add_output_merge_section(Output_section_data* posd,
bool is_string, uint64_t entsize)
{
Input_section inp(posd, is_string, entsize);
this->add_output_section_data(&inp);
}
// Add an input section to a SHF_MERGE section.
bool
Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
uint64_t flags, uint64_t entsize,
uint64_t addralign,
bool keeps_input_sections)
{
bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
// We only merge strings if the alignment is not more than the
// character size. This could be handled, but it's unusual.
if (is_string && addralign > entsize)
return false;
// We cannot restore merged input section states.
gold_assert(this->checkpoint_ == NULL);
// Look up merge sections by required properties.
// Currently, we only invalidate the lookup maps in script processing
// and relaxation. We should not have done either when we reach here.
// So we assume that the lookup maps are valid to simply code.
gold_assert(this->lookup_maps_->is_valid());
Merge_section_properties msp(is_string, entsize, addralign);
Output_merge_base* pomb = this->lookup_maps_->find_merge_section(msp);
bool is_new = false;
if (pomb != NULL)
{
gold_assert(pomb->is_string() == is_string
&& pomb->entsize() == entsize
&& pomb->addralign() == addralign);
}
else
{
// Create a new Output_merge_data or Output_merge_string_data.
if (!is_string)
pomb = new Output_merge_data(entsize, addralign);
else
{
switch (entsize)
{
case 1:
pomb = new Output_merge_string<char>(addralign);
break;
case 2:
pomb = new Output_merge_string<uint16_t>(addralign);
break;
case 4:
pomb = new Output_merge_string<uint32_t>(addralign);
break;
default:
return false;
}
}
// If we need to do script processing or relaxation, we need to keep
// the original input sections to rebuild the fast lookup maps.
if (keeps_input_sections)
pomb->set_keeps_input_sections();
is_new = true;
}
if (pomb->add_input_section(object, shndx))
{
// Add new merge section to this output section and link merge
// section properties to new merge section in map.
if (is_new)
{
this->add_output_merge_section(pomb, is_string, entsize);
this->lookup_maps_->add_merge_section(msp, pomb);
}
// Add input section to new merge section and link input section to new
// merge section in map.
this->lookup_maps_->add_merge_input_section(object, shndx, pomb);
return true;
}
else
{
// If add_input_section failed, delete new merge section to avoid
// exporting empty merge sections in Output_section::get_input_section.
if (is_new)
delete pomb;
return false;
}
}
// Build a relaxation map to speed up relaxation of existing input sections.
// Look up to the first LIMIT elements in INPUT_SECTIONS.
void
Output_section::build_relaxation_map(
const Input_section_list& input_sections,
size_t limit,
Relaxation_map* relaxation_map) const
{
for (size_t i = 0; i < limit; ++i)
{
const Input_section& is(input_sections[i]);
if (is.is_input_section() || is.is_relaxed_input_section())
{
Section_id sid(is.relobj(), is.shndx());
(*relaxation_map)[sid] = i;
}
}
}
// Convert regular input sections in INPUT_SECTIONS into relaxed input
// sections in RELAXED_SECTIONS. MAP is a prebuilt map from section id
// indices of INPUT_SECTIONS.
void
Output_section::convert_input_sections_in_list_to_relaxed_sections(
const std::vector<Output_relaxed_input_section*>& relaxed_sections,
const Relaxation_map& map,
Input_section_list* input_sections)
{
for (size_t i = 0; i < relaxed_sections.size(); ++i)
{
Output_relaxed_input_section* poris = relaxed_sections[i];
Section_id sid(poris->relobj(), poris->shndx());
Relaxation_map::const_iterator p = map.find(sid);
gold_assert(p != map.end());
gold_assert((*input_sections)[p->second].is_input_section());
(*input_sections)[p->second] = Input_section(poris);
}
}
// Convert regular input sections into relaxed input sections. RELAXED_SECTIONS
// is a vector of pointers to Output_relaxed_input_section or its derived
// classes. The relaxed sections must correspond to existing input sections.
void
Output_section::convert_input_sections_to_relaxed_sections(
const std::vector<Output_relaxed_input_section*>& relaxed_sections)
{
gold_assert(parameters->target().may_relax());
// We want to make sure that restore_states does not undo the effect of
// this. If there is no checkpoint active, just search the current
// input section list and replace the sections there. If there is
// a checkpoint, also replace the sections there.
// By default, we look at the whole list.
size_t limit = this->input_sections_.size();
if (this->checkpoint_ != NULL)
{
// Replace input sections with relaxed input section in the saved
// copy of the input section list.
if (this->checkpoint_->input_sections_saved())
{
Relaxation_map map;
this->build_relaxation_map(
*(this->checkpoint_->input_sections()),
this->checkpoint_->input_sections()->size(),
&map);
this->convert_input_sections_in_list_to_relaxed_sections(
relaxed_sections,
map,
this->checkpoint_->input_sections());
}
else
{
// We have not copied the input section list yet. Instead, just
// look at the portion that would be saved.
limit = this->checkpoint_->input_sections_size();
}
}
// Convert input sections in input_section_list.
Relaxation_map map;
this->build_relaxation_map(this->input_sections_, limit, &map);
this->convert_input_sections_in_list_to_relaxed_sections(
relaxed_sections,
map,
&this->input_sections_);
// Update fast look-up map.
if (this->lookup_maps_->is_valid())
for (size_t i = 0; i < relaxed_sections.size(); ++i)
{
Output_relaxed_input_section* poris = relaxed_sections[i];
this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
poris->shndx(), poris);
}
}
// Update the output section flags based on input section flags.
void
Output_section::update_flags_for_input_section(elfcpp::Elf_Xword flags)
{
// If we created the section with SHF_ALLOC clear, we set the
// address. If we are now setting the SHF_ALLOC flag, we need to
// undo that.
if ((this->flags_ & elfcpp::SHF_ALLOC) == 0
&& (flags & elfcpp::SHF_ALLOC) != 0)
this->mark_address_invalid();
this->flags_ |= (flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR));
if ((flags & elfcpp::SHF_MERGE) == 0)
this->flags_ &=~ elfcpp::SHF_MERGE;
else
{
if (this->current_data_size_for_child() == 0)
this->flags_ |= elfcpp::SHF_MERGE;
}
if ((flags & elfcpp::SHF_STRINGS) == 0)
this->flags_ &=~ elfcpp::SHF_STRINGS;
else
{
if (this->current_data_size_for_child() == 0)
this->flags_ |= elfcpp::SHF_STRINGS;
}
}
// Find the merge section into which an input section with index SHNDX in
// OBJECT has been added. Return NULL if none found.
Output_section_data*
Output_section::find_merge_section(const Relobj* object,
unsigned int shndx) const
{
if (!this->lookup_maps_->is_valid())
this->build_lookup_maps();
return this->lookup_maps_->find_merge_section(object, shndx);
}
// Build the lookup maps for merge and relaxed sections. This is needs
// to be declared as a const methods so that it is callable with a const
// Output_section pointer. The method only updates states of the maps.
void
Output_section::build_lookup_maps() const
{
this->lookup_maps_->clear();
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
if (p->is_merge_section())
{
Output_merge_base* pomb = p->output_merge_base();
Merge_section_properties msp(pomb->is_string(), pomb->entsize(),
pomb->addralign());
this->lookup_maps_->add_merge_section(msp, pomb);
for (Output_merge_base::Input_sections::const_iterator is =
pomb->input_sections_begin();
is != pomb->input_sections_end();
++is)
{
const Const_section_id& csid = *is;
this->lookup_maps_->add_merge_input_section(csid.first,
csid.second, pomb);
}
}
else if (p->is_relaxed_input_section())
{
Output_relaxed_input_section* poris = p->relaxed_input_section();
this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
poris->shndx(), poris);
}
}
}
// Find an relaxed input section corresponding to an input section
// in OBJECT with index SHNDX.
const Output_relaxed_input_section*
Output_section::find_relaxed_input_section(const Relobj* object,
unsigned int shndx) const
{
if (!this->lookup_maps_->is_valid())
this->build_lookup_maps();
return this->lookup_maps_->find_relaxed_input_section(object, shndx);
}
// Given an address OFFSET relative to the start of input section
// SHNDX in OBJECT, return whether this address is being included in
// the final link. This should only be called if SHNDX in OBJECT has
// a special mapping.
bool
Output_section::is_input_address_mapped(const Relobj* object,
unsigned int shndx,
off_t offset) const
{
// Look at the Output_section_data_maps first.
const Output_section_data* posd = this->find_merge_section(object, shndx);
if (posd == NULL)
posd = this->find_relaxed_input_section(object, shndx);
if (posd != NULL)
{
section_offset_type output_offset;
bool found = posd->output_offset(object, shndx, offset, &output_offset);
gold_assert(found);
return output_offset != -1;
}
// Fall back to the slow look-up.
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
section_offset_type output_offset;
if (p->output_offset(object, shndx, offset, &output_offset))
return output_offset != -1;
}
// By default we assume that the address is mapped. This should
// only be called after we have passed all sections to Layout. At
// that point we should know what we are discarding.
return true;
}
// Given an address OFFSET relative to the start of input section
// SHNDX in object OBJECT, return the output offset relative to the
// start of the input section in the output section. This should only
// be called if SHNDX in OBJECT has a special mapping.
section_offset_type
Output_section::output_offset(const Relobj* object, unsigned int shndx,
section_offset_type offset) const
{
// This can only be called meaningfully when we know the data size
// of this.
gold_assert(this->is_data_size_valid());
// Look at the Output_section_data_maps first.
const Output_section_data* posd = this->find_merge_section(object, shndx);
if (posd == NULL)
posd = this->find_relaxed_input_section(object, shndx);
if (posd != NULL)
{
section_offset_type output_offset;
bool found = posd->output_offset(object, shndx, offset, &output_offset);
gold_assert(found);
return output_offset;
}
// Fall back to the slow look-up.
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
section_offset_type output_offset;
if (p->output_offset(object, shndx, offset, &output_offset))
return output_offset;
}
gold_unreachable();
}
// Return the output virtual address of OFFSET relative to the start
// of input section SHNDX in object OBJECT.
uint64_t
Output_section::output_address(const Relobj* object, unsigned int shndx,
off_t offset) const
{
uint64_t addr = this->address() + this->first_input_offset_;
// Look at the Output_section_data_maps first.
const Output_section_data* posd = this->find_merge_section(object, shndx);
if (posd == NULL)
posd = this->find_relaxed_input_section(object, shndx);
if (posd != NULL && posd->is_address_valid())
{
section_offset_type output_offset;
bool found = posd->output_offset(object, shndx, offset, &output_offset);
gold_assert(found);
return posd->address() + output_offset;
}
// Fall back to the slow look-up.
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
addr = align_address(addr, p->addralign());
section_offset_type output_offset;
if (p->output_offset(object, shndx, offset, &output_offset))
{
if (output_offset == -1)
return -1ULL;
return addr + output_offset;
}
addr += p->data_size();
}
// If we get here, it means that we don't know the mapping for this
// input section. This might happen in principle if
// add_input_section were called before add_output_section_data.
// But it should never actually happen.
gold_unreachable();
}
// Find the output address of the start of the merged section for
// input section SHNDX in object OBJECT.
bool
Output_section::find_starting_output_address(const Relobj* object,
unsigned int shndx,
uint64_t* paddr) const
{
// FIXME: This becomes a bottle-neck if we have many relaxed sections.
// Looking up the merge section map does not always work as we sometimes
// find a merge section without its address set.
uint64_t addr = this->address() + this->first_input_offset_;
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
addr = align_address(addr, p->addralign());
// It would be nice if we could use the existing output_offset
// method to get the output offset of input offset 0.
// Unfortunately we don't know for sure that input offset 0 is
// mapped at all.
if (p->is_merge_section_for(object, shndx))
{
*paddr = addr;
return true;
}
addr += p->data_size();
}
// We couldn't find a merge output section for this input section.
return false;
}
// Set the data size of an Output_section. This is where we handle
// setting the addresses of any Output_section_data objects.
void
Output_section::set_final_data_size()
{
if (this->input_sections_.empty())
{
this->set_data_size(this->current_data_size_for_child());
return;
}
if (this->must_sort_attached_input_sections()
|| this->input_section_order_specified())
this->sort_attached_input_sections();
uint64_t address = this->address();
off_t startoff = this->offset();
off_t off = startoff + this->first_input_offset_;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
off = align_address(off, p->addralign());
p->set_address_and_file_offset(address + (off - startoff), off,
startoff);
off += p->data_size();
}
this->set_data_size(off - startoff);
}
// Reset the address and file offset.
void
Output_section::do_reset_address_and_file_offset()
{
// An unallocated section has no address. Forcing this means that
// we don't need special treatment for symbols defined in debug
// sections. We do the same in the constructor. This does not
// apply to NOLOAD sections though.
if (((this->flags_ & elfcpp::SHF_ALLOC) == 0) && !this->is_noload_)
this->set_address(0);
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
p->reset_address_and_file_offset();
}
// Return true if address and file offset have the values after reset.
bool
Output_section::do_address_and_file_offset_have_reset_values() const
{
if (this->is_offset_valid())
return false;
// An unallocated section has address 0 after its construction or a reset.
if ((this->flags_ & elfcpp::SHF_ALLOC) == 0)
return this->is_address_valid() && this->address() == 0;
else
return !this->is_address_valid();
}
// Set the TLS offset. Called only for SHT_TLS sections.
void
Output_section::do_set_tls_offset(uint64_t tls_base)
{
this->tls_offset_ = this->address() - tls_base;
}
// In a few cases we need to sort the input sections attached to an
// output section. This is used to implement the type of constructor
// priority ordering implemented by the GNU linker, in which the
// priority becomes part of the section name and the sections are
// sorted by name. We only do this for an output section if we see an
// attached input section matching ".ctor.*", ".dtor.*",
// ".init_array.*" or ".fini_array.*".
class Output_section::Input_section_sort_entry
{
public:
Input_section_sort_entry()
: input_section_(), index_(-1U), section_has_name_(false),
section_name_()
{ }
Input_section_sort_entry(const Input_section& input_section,
unsigned int index,
bool must_sort_attached_input_sections)
: input_section_(input_section), index_(index),
section_has_name_(input_section.is_input_section()
|| input_section.is_relaxed_input_section())
{
if (this->section_has_name_
&& must_sort_attached_input_sections)
{
// This is only called single-threaded from Layout::finalize,
// so it is OK to lock. Unfortunately we have no way to pass
// in a Task token.
const Task* dummy_task = reinterpret_cast<const Task*>(-1);
Object* obj = (input_section.is_input_section()
? input_section.relobj()
: input_section.relaxed_input_section()->relobj());
Task_lock_obj<Object> tl(dummy_task, obj);
// This is a slow operation, which should be cached in
// Layout::layout if this becomes a speed problem.
this->section_name_ = obj->section_name(input_section.shndx());
}
}
// Return the Input_section.
const Input_section&
input_section() const
{
gold_assert(this->index_ != -1U);
return this->input_section_;
}
// The index of this entry in the original list. This is used to
// make the sort stable.
unsigned int
index() const
{
gold_assert(this->index_ != -1U);
return this->index_;
}
// Whether there is a section name.
bool
section_has_name() const
{ return this->section_has_name_; }
// The section name.
const std::string&
section_name() const
{
gold_assert(this->section_has_name_);
return this->section_name_;
}
// Return true if the section name has a priority. This is assumed
// to be true if it has a dot after the initial dot.
bool
has_priority() const
{
gold_assert(this->section_has_name_);
return this->section_name_.find('.', 1) != std::string::npos;
}
// Return true if this an input file whose base name matches
// FILE_NAME. The base name must have an extension of ".o", and
// must be exactly FILE_NAME.o or FILE_NAME, one character, ".o".
// This is to match crtbegin.o as well as crtbeginS.o without
// getting confused by other possibilities. Overall matching the
// file name this way is a dreadful hack, but the GNU linker does it
// in order to better support gcc, and we need to be compatible.
bool
match_file_name(const char* match_file_name) const
{
const std::string& file_name(this->input_section_.relobj()->name());
const char* base_name = lbasename(file_name.c_str());
size_t match_len = strlen(match_file_name);
if (strncmp(base_name, match_file_name, match_len) != 0)
return false;
size_t base_len = strlen(base_name);
if (base_len != match_len + 2 && base_len != match_len + 3)
return false;
return memcmp(base_name + base_len - 2, ".o", 2) == 0;
}
// Returns 1 if THIS should appear before S in section order, -1 if S
// appears before THIS and 0 if they are not comparable.
int
compare_section_ordering(const Input_section_sort_entry& s) const
{
unsigned int this_secn_index = this->input_section_.section_order_index();
unsigned int s_secn_index = s.input_section().section_order_index();
if (this_secn_index > 0 && s_secn_index > 0)
{
if (this_secn_index < s_secn_index)
return 1;
else if (this_secn_index > s_secn_index)
return -1;
}
return 0;
}
private:
// The Input_section we are sorting.
Input_section input_section_;
// The index of this Input_section in the original list.
unsigned int index_;
// Whether this Input_section has a section name--it won't if this
// is some random Output_section_data.
bool section_has_name_;
// The section name if there is one.
std::string section_name_;
};
// Return true if S1 should come before S2 in the output section.
bool
Output_section::Input_section_sort_compare::operator()(
const Output_section::Input_section_sort_entry& s1,
const Output_section::Input_section_sort_entry& s2) const
{
// crtbegin.o must come first.
bool s1_begin = s1.match_file_name("crtbegin");
bool s2_begin = s2.match_file_name("crtbegin");
if (s1_begin || s2_begin)
{
if (!s1_begin)
return false;
if (!s2_begin)
return true;
return s1.index() < s2.index();
}
// crtend.o must come last.
bool s1_end = s1.match_file_name("crtend");
bool s2_end = s2.match_file_name("crtend");
if (s1_end || s2_end)
{
if (!s1_end)
return true;
if (!s2_end)
return false;
return s1.index() < s2.index();
}
// We sort all the sections with no names to the end.
if (!s1.section_has_name() || !s2.section_has_name())
{
if (s1.section_has_name())
return true;
if (s2.section_has_name())
return false;
return s1.index() < s2.index();
}
// A section with a priority follows a section without a priority.
bool s1_has_priority = s1.has_priority();
bool s2_has_priority = s2.has_priority();
if (s1_has_priority && !s2_has_priority)
return false;
if (!s1_has_priority && s2_has_priority)
return true;
// Check if a section order exists for these sections through a section
// ordering file. If sequence_num is 0, an order does not exist.
int sequence_num = s1.compare_section_ordering(s2);
if (sequence_num != 0)
return sequence_num == 1;
// Otherwise we sort by name.
int compare = s1.section_name().compare(s2.section_name());
if (compare != 0)
return compare < 0;
// Otherwise we keep the input order.
return s1.index() < s2.index();
}
// Return true if S1 should come before S2 in an .init_array or .fini_array
// output section.
bool
Output_section::Input_section_sort_init_fini_compare::operator()(
const Output_section::Input_section_sort_entry& s1,
const Output_section::Input_section_sort_entry& s2) const
{
// We sort all the sections with no names to the end.
if (!s1.section_has_name() || !s2.section_has_name())
{
if (s1.section_has_name())
return true;
if (s2.section_has_name())
return false;
return s1.index() < s2.index();
}
// A section without a priority follows a section with a priority.
// This is the reverse of .ctors and .dtors sections.
bool s1_has_priority = s1.has_priority();
bool s2_has_priority = s2.has_priority();
if (s1_has_priority && !s2_has_priority)
return true;
if (!s1_has_priority && s2_has_priority)
return false;
// Check if a section order exists for these sections through a section
// ordering file. If sequence_num is 0, an order does not exist.
int sequence_num = s1.compare_section_ordering(s2);
if (sequence_num != 0)
return sequence_num == 1;
// Otherwise we sort by name.
int compare = s1.section_name().compare(s2.section_name());
if (compare != 0)
return compare < 0;
// Otherwise we keep the input order.
return s1.index() < s2.index();
}
// Return true if S1 should come before S2. Sections that do not match
// any pattern in the section ordering file are placed ahead of the sections
// that match some pattern.
bool
Output_section::Input_section_sort_section_order_index_compare::operator()(
const Output_section::Input_section_sort_entry& s1,
const Output_section::Input_section_sort_entry& s2) const
{
unsigned int s1_secn_index = s1.input_section().section_order_index();
unsigned int s2_secn_index = s2.input_section().section_order_index();
// Keep input order if section ordering cannot determine order.
if (s1_secn_index == s2_secn_index)
return s1.index() < s2.index();
return s1_secn_index < s2_secn_index;
}
// Sort the input sections attached to an output section.
void
Output_section::sort_attached_input_sections()
{
if (this->attached_input_sections_are_sorted_)
return;
if (this->checkpoint_ != NULL
&& !this->checkpoint_->input_sections_saved())
this->checkpoint_->save_input_sections();
// The only thing we know about an input section is the object and
// the section index. We need the section name. Recomputing this
// is slow but this is an unusual case. If this becomes a speed
// problem we can cache the names as required in Layout::layout.
// We start by building a larger vector holding a copy of each
// Input_section, plus its current index in the list and its name.
std::vector<Input_section_sort_entry> sort_list;
unsigned int i = 0;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p, ++i)
sort_list.push_back(Input_section_sort_entry(*p, i,
this->must_sort_attached_input_sections()));
// Sort the input sections.
if (this->must_sort_attached_input_sections())
{
if (this->type() == elfcpp::SHT_PREINIT_ARRAY
|| this->type() == elfcpp::SHT_INIT_ARRAY
|| this->type() == elfcpp::SHT_FINI_ARRAY)
std::sort(sort_list.begin(), sort_list.end(),
Input_section_sort_init_fini_compare());
else
std::sort(sort_list.begin(), sort_list.end(),
Input_section_sort_compare());
}
else
{
gold_assert(parameters->options().section_ordering_file());
std::sort(sort_list.begin(), sort_list.end(),
Input_section_sort_section_order_index_compare());
}
// Copy the sorted input sections back to our list.
this->input_sections_.clear();
for (std::vector<Input_section_sort_entry>::iterator p = sort_list.begin();
p != sort_list.end();
++p)
this->input_sections_.push_back(p->input_section());
sort_list.clear();
// Remember that we sorted the input sections, since we might get
// called again.
this->attached_input_sections_are_sorted_ = true;
}
// Write the section header to *OSHDR.
template<int size, bool big_endian>
void
Output_section::write_header(const Layout* layout,
const Stringpool* secnamepool,
elfcpp::Shdr_write<size, big_endian>* oshdr) const
{
oshdr->put_sh_name(secnamepool->get_offset(this->name_));
oshdr->put_sh_type(this->type_);
elfcpp::Elf_Xword flags = this->flags_;
if (this->info_section_ != NULL && this->info_uses_section_index_)
flags |= elfcpp::SHF_INFO_LINK;
oshdr->put_sh_flags(flags);
oshdr->put_sh_addr(this->address());
oshdr->put_sh_offset(this->offset());
oshdr->put_sh_size(this->data_size());
if (this->link_section_ != NULL)
oshdr->put_sh_link(this->link_section_->out_shndx());
else if (this->should_link_to_symtab_)
oshdr->put_sh_link(layout->symtab_section()->out_shndx());
else if (this->should_link_to_dynsym_)
oshdr->put_sh_link(layout->dynsym_section()->out_shndx());
else
oshdr->put_sh_link(this->link_);
elfcpp::Elf_Word info;
if (this->info_section_ != NULL)
{
if (this->info_uses_section_index_)
info = this->info_section_->out_shndx();
else
info = this->info_section_->symtab_index();
}
else if (this->info_symndx_ != NULL)
info = this->info_symndx_->symtab_index();
else
info = this->info_;
oshdr->put_sh_info(info);
oshdr->put_sh_addralign(this->addralign_);
oshdr->put_sh_entsize(this->entsize_);
}
// Write out the data. For input sections the data is written out by
// Object::relocate, but we have to handle Output_section_data objects
// here.
void
Output_section::do_write(Output_file* of)
{
gold_assert(!this->requires_postprocessing());
// If the target performs relaxation, we delay filler generation until now.
gold_assert(!this->generate_code_fills_at_write_ || this->fills_.empty());
off_t output_section_file_offset = this->offset();
for (Fill_list::iterator p = this->fills_.begin();
p != this->fills_.end();
++p)
{
std::string fill_data(parameters->target().code_fill(p->length()));
of->write(output_section_file_offset + p->section_offset(),
fill_data.data(), fill_data.size());
}
off_t off = this->offset() + this->first_input_offset_;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
off_t aligned_off = align_address(off, p->addralign());
if (this->generate_code_fills_at_write_ && (off != aligned_off))
{
size_t fill_len = aligned_off - off;
std::string fill_data(parameters->target().code_fill(fill_len));
of->write(off, fill_data.data(), fill_data.size());
}
p->write(of);
off = aligned_off + p->data_size();
}
}
// If a section requires postprocessing, create the buffer to use.
void
Output_section::create_postprocessing_buffer()
{
gold_assert(this->requires_postprocessing());
if (this->postprocessing_buffer_ != NULL)
return;
if (!this->input_sections_.empty())
{
off_t off = this->first_input_offset_;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
off = align_address(off, p->addralign());
p->finalize_data_size();
off += p->data_size();
}
this->set_current_data_size_for_child(off);
}
off_t buffer_size = this->current_data_size_for_child();
this->postprocessing_buffer_ = new unsigned char[buffer_size];
}
// Write all the data of an Output_section into the postprocessing
// buffer. This is used for sections which require postprocessing,
// such as compression. Input sections are handled by
// Object::Relocate.
void
Output_section::write_to_postprocessing_buffer()
{
gold_assert(this->requires_postprocessing());
// If the target performs relaxation, we delay filler generation until now.
gold_assert(!this->generate_code_fills_at_write_ || this->fills_.empty());
unsigned char* buffer = this->postprocessing_buffer();
for (Fill_list::iterator p = this->fills_.begin();
p != this->fills_.end();
++p)
{
std::string fill_data(parameters->target().code_fill(p->length()));
memcpy(buffer + p->section_offset(), fill_data.data(),
fill_data.size());
}
off_t off = this->first_input_offset_;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
off_t aligned_off = align_address(off, p->addralign());
if (this->generate_code_fills_at_write_ && (off != aligned_off))
{
size_t fill_len = aligned_off - off;
std::string fill_data(parameters->target().code_fill(fill_len));
memcpy(buffer + off, fill_data.data(), fill_data.size());
}
p->write_to_buffer(buffer + aligned_off);
off = aligned_off + p->data_size();
}
}
// Get the input sections for linker script processing. We leave
// behind the Output_section_data entries. Note that this may be
// slightly incorrect for merge sections. We will leave them behind,
// but it is possible that the script says that they should follow
// some other input sections, as in:
// .rodata { *(.rodata) *(.rodata.cst*) }
// For that matter, we don't handle this correctly:
// .rodata { foo.o(.rodata.cst*) *(.rodata.cst*) }
// With luck this will never matter.
uint64_t
Output_section::get_input_sections(
uint64_t address,
const std::string& fill,
std::list<Input_section>* input_sections)
{
if (this->checkpoint_ != NULL
&& !this->checkpoint_->input_sections_saved())
this->checkpoint_->save_input_sections();
// Invalidate fast look-up maps.
this->lookup_maps_->invalidate();
uint64_t orig_address = address;
address = align_address(address, this->addralign());
Input_section_list remaining;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
if (p->is_input_section()
|| p->is_relaxed_input_section()
|| p->is_merge_section())
input_sections->push_back(*p);
else
{
uint64_t aligned_address = align_address(address, p->addralign());
if (aligned_address != address && !fill.empty())
{
section_size_type length =
convert_to_section_size_type(aligned_address - address);
std::string this_fill;
this_fill.reserve(length);
while (this_fill.length() + fill.length() <= length)
this_fill += fill;
if (this_fill.length() < length)
this_fill.append(fill, 0, length - this_fill.length());
Output_section_data* posd = new Output_data_const(this_fill, 0);
remaining.push_back(Input_section(posd));
}
address = aligned_address;
remaining.push_back(*p);
p->finalize_data_size();
address += p->data_size();
}
}
this->input_sections_.swap(remaining);
this->first_input_offset_ = 0;
uint64_t data_size = address - orig_address;
this->set_current_data_size_for_child(data_size);
return data_size;
}
// Add a script input section. SIS is an Output_section::Input_section,
// which can be either a plain input section or a special input section like
// a relaxed input section. For a special input section, its size must be
// finalized.
void
Output_section::add_script_input_section(const Input_section& sis)
{
uint64_t data_size = sis.data_size();
uint64_t addralign = sis.addralign();
if (addralign > this->addralign_)
this->addralign_ = addralign;
off_t offset_in_section = this->current_data_size_for_child();
off_t aligned_offset_in_section = align_address(offset_in_section,
addralign);
this->set_current_data_size_for_child(aligned_offset_in_section
+ data_size);
this->input_sections_.push_back(sis);
// Update fast lookup maps if necessary.
if (this->lookup_maps_->is_valid())
{
if (sis.is_merge_section())
{
Output_merge_base* pomb = sis.output_merge_base();
Merge_section_properties msp(pomb->is_string(), pomb->entsize(),
pomb->addralign());
this->lookup_maps_->add_merge_section(msp, pomb);
for (Output_merge_base::Input_sections::const_iterator p =
pomb->input_sections_begin();
p != pomb->input_sections_end();
++p)
this->lookup_maps_->add_merge_input_section(p->first, p->second,
pomb);
}
else if (sis.is_relaxed_input_section())
{
Output_relaxed_input_section* poris = sis.relaxed_input_section();
this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
poris->shndx(), poris);
}
}
}
// Save states for relaxation.
void
Output_section::save_states()
{
gold_assert(this->checkpoint_ == NULL);
Checkpoint_output_section* checkpoint =
new Checkpoint_output_section(this->addralign_, this->flags_,
this->input_sections_,
this->first_input_offset_,
this->attached_input_sections_are_sorted_);
this->checkpoint_ = checkpoint;
gold_assert(this->fills_.empty());
}
void
Output_section::discard_states()
{
gold_assert(this->checkpoint_ != NULL);
delete this->checkpoint_;
this->checkpoint_ = NULL;
gold_assert(this->fills_.empty());
// Simply invalidate the fast lookup maps since we do not keep
// track of them.
this->lookup_maps_->invalidate();
}
void
Output_section::restore_states()
{
gold_assert(this->checkpoint_ != NULL);
Checkpoint_output_section* checkpoint = this->checkpoint_;
this->addralign_ = checkpoint->addralign();
this->flags_ = checkpoint->flags();
this->first_input_offset_ = checkpoint->first_input_offset();
if (!checkpoint->input_sections_saved())
{
// If we have not copied the input sections, just resize it.
size_t old_size = checkpoint->input_sections_size();
gold_assert(this->input_sections_.size() >= old_size);
this->input_sections_.resize(old_size);
}
else
{
// We need to copy the whole list. This is not efficient for
// extremely large output with hundreads of thousands of input
// objects. We may need to re-think how we should pass sections
// to scripts.
this->input_sections_ = *checkpoint->input_sections();
}
this->attached_input_sections_are_sorted_ =
checkpoint->attached_input_sections_are_sorted();
// Simply invalidate the fast lookup maps since we do not keep
// track of them.
this->lookup_maps_->invalidate();
}
// Update the section offsets of input sections in this. This is required if
// relaxation causes some input sections to change sizes.
void
Output_section::adjust_section_offsets()
{
if (!this->section_offsets_need_adjustment_)
return;
off_t off = 0;
for (Input_section_list::iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
{
off = align_address(off, p->addralign());
if (p->is_input_section())
p->relobj()->set_section_offset(p->shndx(), off);
off += p->data_size();
}
this->section_offsets_need_adjustment_ = false;
}
// Print to the map file.
void
Output_section::do_print_to_mapfile(Mapfile* mapfile) const
{
mapfile->print_output_section(this);
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
p->print_to_mapfile(mapfile);
}
// Print stats for merge sections to stderr.
void
Output_section::print_merge_stats()
{
Input_section_list::iterator p;
for (p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
p->print_merge_stats(this->name_);
}
// Output segment methods.
Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
: output_data_(),
output_bss_(),
vaddr_(0),
paddr_(0),
memsz_(0),
max_align_(0),
min_p_align_(0),
offset_(0),
filesz_(0),
type_(type),
flags_(flags),
is_max_align_known_(false),
are_addresses_set_(false),
is_large_data_segment_(false)
{
// The ELF ABI specifies that a PT_TLS segment always has PF_R as
// the flags.
if (type == elfcpp::PT_TLS)
this->flags_ = elfcpp::PF_R;
}
// Add an Output_section to an Output_segment.
void
Output_segment::add_output_section(Output_section* os,
elfcpp::Elf_Word seg_flags,
bool do_sort)
{
gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
gold_assert(!this->is_max_align_known_);
gold_assert(os->is_large_data_section() == this->is_large_data_segment());
gold_assert(this->type() == elfcpp::PT_LOAD || !do_sort);
this->update_flags_for_output_section(seg_flags);
Output_segment::Output_data_list* pdl;
if (os->type() == elfcpp::SHT_NOBITS)
pdl = &this->output_bss_;
else
pdl = &this->output_data_;
// Note that while there may be many input sections in an output
// section, there are normally only a few output sections in an
// output segment. The loops below are expected to be fast.
// So that PT_NOTE segments will work correctly, we need to ensure
// that all SHT_NOTE sections are adjacent.
if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
{
Output_segment::Output_data_list::iterator p = pdl->end();
do
{
--p;
if ((*p)->is_section_type(elfcpp::SHT_NOTE))
{
++p;
pdl->insert(p, os);
return;
}
}
while (p != pdl->begin());
}
// Similarly, so that PT_TLS segments will work, we need to group
// SHF_TLS sections. An SHF_TLS/SHT_NOBITS section is a special
// case: we group the SHF_TLS/SHT_NOBITS sections right after the
// SHF_TLS/SHT_PROGBITS sections. This lets us set up PT_TLS
// correctly. SHF_TLS sections get added to both a PT_LOAD segment
// and the PT_TLS segment; we do this grouping only for the PT_LOAD
// segment.
if (this->type_ != elfcpp::PT_TLS
&& (os->flags() & elfcpp::SHF_TLS) != 0)
{
pdl = &this->output_data_;
if (!pdl->empty())
{
bool nobits = os->type() == elfcpp::SHT_NOBITS;
bool sawtls = false;
Output_segment::Output_data_list::iterator p = pdl->end();
gold_assert(p != pdl->begin());
do
{
--p;
bool insert;
if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
{
sawtls = true;
// Put a NOBITS section after the first TLS section.
// Put a PROGBITS section after the first
// TLS/PROGBITS section.
insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
}
else
{
// If we've gone past the TLS sections, but we've
// seen a TLS section, then we need to insert this
// section now.
insert = sawtls;
}
if (insert)
{
++p;
pdl->insert(p, os);
return;
}
}
while (p != pdl->begin());
}
// There are no TLS sections yet; put this one at the requested
// location in the section list.
}
if (do_sort)
{
// For the PT_GNU_RELRO segment, we need to group relro
// sections, and we need to put them before any non-relro
// sections. Any relro local sections go before relro non-local
// sections. One section may be marked as the last relro
// section.
if (os->is_relro())
{
gold_assert(pdl == &this->output_data_);
Output_segment::Output_data_list::iterator p;
for (p = pdl->begin(); p != pdl->end(); ++p)
{
if (!(*p)->is_section())
break;
Output_section* pos = (*p)->output_section();
if (!pos->is_relro()
|| (os->is_relro_local() && !pos->is_relro_local())
|| (!os->is_last_relro() && pos->is_last_relro()))
break;
}
pdl->insert(p, os);
return;
}
// One section may be marked as the first section which follows
// the relro sections.
if (os->is_first_non_relro())
{
gold_assert(pdl == &this->output_data_);
Output_segment::Output_data_list::iterator p;
for (p = pdl->begin(); p != pdl->end(); ++p)
{
if (!(*p)->is_section())
break;
Output_section* pos = (*p)->output_section();
if (!pos->is_relro())
break;
}
pdl->insert(p, os);
return;
}
}
// Small data sections go at the end of the list of data sections.
// If OS is not small, and there are small sections, we have to
// insert it before the first small section.
if (os->type() != elfcpp::SHT_NOBITS
&& !os->is_small_section()
&& !pdl->empty()
&& pdl->back()->is_section()
&& pdl->back()->output_section()->is_small_section())
{
for (Output_segment::Output_data_list::iterator p = pdl->begin();
p != pdl->end();
++p)
{
if ((*p)->is_section()
&& (*p)->output_section()->is_small_section())
{
pdl->insert(p, os);
return;
}
}
gold_unreachable();
}
// A small BSS section goes at the start of the BSS sections, after
// other small BSS sections.
if (os->type() == elfcpp::SHT_NOBITS && os->is_small_section())
{
for (Output_segment::Output_data_list::iterator p = pdl->begin();
p != pdl->end();
++p)
{
if (!(*p)->is_section()
|| !(*p)->output_section()->is_small_section())
{
pdl->insert(p, os);
return;
}
}
}
// A large BSS section goes at the end of the BSS sections, which
// means that one that is not large must come before the first large
// one.
if (os->type() == elfcpp::SHT_NOBITS
&& !os->is_large_section()
&& !pdl->empty()
&& pdl->back()->is_section()
&& pdl->back()->output_section()->is_large_section())
{
for (Output_segment::Output_data_list::iterator p = pdl->begin();
p != pdl->end();
++p)
{
if ((*p)->is_section()
&& (*p)->output_section()->is_large_section())
{
pdl->insert(p, os);
return;
}
}
gold_unreachable();
}
// We do some further output section sorting in order to make the
// generated program run more efficiently. We should only do this
// when not using a linker script, so it is controled by the DO_SORT
// parameter.
if (do_sort)
{
// FreeBSD requires the .interp section to be in the first page
// of the executable. That is a more efficient location anyhow
// for any OS, since it means that the kernel will have the data
// handy after it reads the program headers.
if (os->is_interp() && !pdl->empty())
{
pdl->insert(pdl->begin(), os);
return;
}
// Put loadable non-writable notes immediately after the .interp
// sections, so that the PT_NOTE segment is on the first page of
// the executable.
if (os->type() == elfcpp::SHT_NOTE
&& (os->flags() & elfcpp::SHF_WRITE) == 0
&& !pdl->empty())
{
Output_segment::Output_data_list::iterator p = pdl->begin();
if ((*p)->is_section() && (*p)->output_section()->is_interp())
++p;
pdl->insert(p, os);
return;
}
// If this section is used by the dynamic linker, and it is not
// writable, then put it first, after the .interp section and
// any loadable notes. This makes it more likely that the
// dynamic linker will have to read less data from the disk.
if (os->is_dynamic_linker_section()
&& !pdl->empty()
&& (os->flags() & elfcpp::SHF_WRITE) == 0)
{
bool is_reloc = (os->type() == elfcpp::SHT_REL
|| os->type() == elfcpp::SHT_RELA);
Output_segment::Output_data_list::iterator p = pdl->begin();
while (p != pdl->end()
&& (*p)->is_section()
&& ((*p)->output_section()->is_dynamic_linker_section()
|| (*p)->output_section()->type() == elfcpp::SHT_NOTE))
{
// Put reloc sections after the other ones. Putting the
// dynamic reloc sections first confuses BFD, notably
// objcopy and strip.
if (!is_reloc
&& ((*p)->output_section()->type() == elfcpp::SHT_REL
|| (*p)->output_section()->type() == elfcpp::SHT_RELA))
break;
++p;
}
pdl->insert(p, os);
return;
}
}
// If there were no constraints on the output section, just add it
// to the end of the list.
pdl->push_back(os);
}
// Remove an Output_section from this segment. It is an error if it
// is not present.
void
Output_segment::remove_output_section(Output_section* os)
{
// We only need this for SHT_PROGBITS.
gold_assert(os->type() == elfcpp::SHT_PROGBITS);
for (Output_data_list::iterator p = this->output_data_.begin();
p != this->output_data_.end();
++p)
{
if (*p == os)
{
this->output_data_.erase(p);
return;
}
}
gold_unreachable();
}
// Add an Output_data (which need not be an Output_section) to the
// start of a segment.
void
Output_segment::add_initial_output_data(Output_data* od)
{
gold_assert(!this->is_max_align_known_);
this->output_data_.push_front(od);
}
// Return whether the first data section is a relro section.
bool
Output_segment::is_first_section_relro() const
{
return (!this->output_data_.empty()
&& this->output_data_.front()->is_section()
&& this->output_data_.front()->output_section()->is_relro());
}
// Return the maximum alignment of the Output_data in Output_segment.
uint64_t
Output_segment::maximum_alignment()
{
if (!this->is_max_align_known_)
{
uint64_t addralign;
addralign = Output_segment::maximum_alignment_list(&this->output_data_);
if (addralign > this->max_align_)
this->max_align_ = addralign;
addralign = Output_segment::maximum_alignment_list(&this->output_bss_);
if (addralign > this->max_align_)
this->max_align_ = addralign;
this->is_max_align_known_ = true;
}
return this->max_align_;
}
// Return the maximum alignment of a list of Output_data.
uint64_t
Output_segment::maximum_alignment_list(const Output_data_list* pdl)
{
uint64_t ret = 0;
for (Output_data_list::const_iterator p = pdl->begin();
p != pdl->end();
++p)
{
uint64_t addralign = (*p)->addralign();
if (addralign > ret)
ret = addralign;
}
return ret;
}
// Return the number of dynamic relocs applied to this segment.
unsigned int
Output_segment::dynamic_reloc_count() const
{
return (this->dynamic_reloc_count_list(&this->output_data_)
+ this->dynamic_reloc_count_list(&this->output_bss_));
}
// Return the number of dynamic relocs applied to an Output_data_list.
unsigned int
Output_segment::dynamic_reloc_count_list(const Output_data_list* pdl) const
{
unsigned int count = 0;
for (Output_data_list::const_iterator p = pdl->begin();
p != pdl->end();
++p)
count += (*p)->dynamic_reloc_count();
return count;
}
// Set the section addresses for an Output_segment. If RESET is true,
// reset the addresses first. ADDR is the address and *POFF is the
// file offset. Set the section indexes starting with *PSHNDX.
// Return the address of the immediately following segment. Update
// *POFF and *PSHNDX.
uint64_t
Output_segment::set_section_addresses(const Layout* layout, bool reset,
uint64_t addr,
unsigned int increase_relro,
off_t* poff,
unsigned int* pshndx)
{
gold_assert(this->type_ == elfcpp::PT_LOAD);
off_t orig_off = *poff;
// If we have relro sections, we need to pad forward now so that the
// relro sections plus INCREASE_RELRO end on a common page boundary.
if (parameters->options().relro()
&& this->is_first_section_relro()
&& (!this->are_addresses_set_ || reset))
{
uint64_t relro_size = 0;
off_t off = *poff;
for (Output_data_list::iterator p = this->output_data_.begin();
p != this->output_data_.end();
++p)
{
if (!(*p)->is_section())
break;
Output_section* pos = (*p)->output_section();
if (!pos->is_relro())
break;
gold_assert(!(*p)->is_section_flag_set(elfcpp::SHF_TLS));
if ((*p)->is_address_valid())
relro_size += (*p)->data_size();
else
{
// FIXME: This could be faster.
(*p)->set_address_and_file_offset(addr + relro_size,
off + relro_size);
relro_size += (*p)->data_size();
(*p)->reset_address_and_file_offset();
}
}
relro_size += increase_relro;
uint64_t page_align = parameters->target().common_pagesize();
// Align to offset N such that (N + RELRO_SIZE) % PAGE_ALIGN == 0.
uint64_t desired_align = page_align - (relro_size % page_align);
if (desired_align < *poff % page_align)
*poff += page_align - *poff % page_align;
*poff += desired_align - *poff % page_align;
addr += *poff - orig_off;
orig_off = *poff;
}
if (!reset && this->are_addresses_set_)
{
gold_assert(this->paddr_ == addr);
addr = this->vaddr_;
}
else
{
this->vaddr_ = addr;
this->paddr_ = addr;
this->are_addresses_set_ = true;
}
bool in_tls = false;
this->offset_ = orig_off;
addr = this->set_section_list_addresses(layout, reset, &this->output_data_,
addr, poff, pshndx, &in_tls);
this->filesz_ = *poff - orig_off;
off_t off = *poff;
uint64_t ret = this->set_section_list_addresses(layout, reset,
&this->output_bss_,
addr, poff, pshndx,
&in_tls);
// If the last section was a TLS section, align upward to the
// alignment of the TLS segment, so that the overall size of the TLS
// segment is aligned.
if (in_tls)
{
uint64_t segment_align = layout->tls_segment()->maximum_alignment();
*poff = align_address(*poff, segment_align);
}
this->memsz_ = *poff - orig_off;
// Ignore the file offset adjustments made by the BSS Output_data
// objects.
*poff = off;
return ret;
}
// Set the addresses and file offsets in a list of Output_data
// structures.
uint64_t
Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
Output_data_list* pdl,
uint64_t addr, off_t* poff,
unsigned int* pshndx,
bool* in_tls)
{
off_t startoff = *poff;
off_t off = startoff;
for (Output_data_list::iterator p = pdl->begin();
p != pdl->end();
++p)
{
if (reset)
(*p)->reset_address_and_file_offset();
// When using a linker script the section will most likely
// already have an address.
if (!(*p)->is_address_valid())
{
uint64_t align = (*p)->addralign();
if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
{
// Give the first TLS section the alignment of the
// entire TLS segment. Otherwise the TLS segment as a
// whole may be misaligned.
if (!*in_tls)
{
Output_segment* tls_segment = layout->tls_segment();
gold_assert(tls_segment != NULL);
uint64_t segment_align = tls_segment->maximum_alignment();
gold_assert(segment_align >= align);
align = segment_align;
*in_tls = true;
}
}
else
{
// If this is the first section after the TLS segment,
// align it to at least the alignment of the TLS
// segment, so that the size of the overall TLS segment
// is aligned.
if (*in_tls)
{
uint64_t segment_align =
layout->tls_segment()->maximum_alignment();
if (segment_align > align)
align = segment_align;
*in_tls = false;
}
}
off = align_address(off, align);
(*p)->set_address_and_file_offset(addr + (off - startoff), off);
}
else
{
// The script may have inserted a skip forward, but it
// better not have moved backward.
if ((*p)->address() >= addr + (off - startoff))
off += (*p)->address() - (addr + (off - startoff));
else
{
if (!layout->script_options()->saw_sections_clause())
gold_unreachable();
else
{
Output_section* os = (*p)->output_section();
// Cast to unsigned long long to avoid format warnings.
unsigned long long previous_dot =
static_cast<unsigned long long>(addr + (off - startoff));
unsigned long long dot =
static_cast<unsigned long long>((*p)->address());
if (os == NULL)
gold_error(_("dot moves backward in linker script "
"from 0x%llx to 0x%llx"), previous_dot, dot);
else
gold_error(_("address of section '%s' moves backward "
"from 0x%llx to 0x%llx"),
os->name(), previous_dot, dot);
}
}
(*p)->set_file_offset(off);
(*p)->finalize_data_size();
}
// We want to ignore the size of a SHF_TLS or SHT_NOBITS
// section. Such a section does not affect the size of a
// PT_LOAD segment.
if (!(*p)->is_section_flag_set(elfcpp::SHF_TLS)
|| !(*p)->is_section_type(elfcpp::SHT_NOBITS))
off += (*p)->data_size();
if ((*p)->is_section())
{
(*p)->set_out_shndx(*pshndx);
++*pshndx;
}
}
*poff = off;
return addr + (off - startoff);
}
// For a non-PT_LOAD segment, set the offset from the sections, if
// any. Add INCREASE to the file size and the memory size.
void
Output_segment::set_offset(unsigned int increase)
{
gold_assert(this->type_ != elfcpp::PT_LOAD);
gold_assert(!this->are_addresses_set_);
if (this->output_data_.empty() && this->output_bss_.empty())
{
gold_assert(increase == 0);
this->vaddr_ = 0;
this->paddr_ = 0;
this->are_addresses_set_ = true;
this->memsz_ = 0;
this->min_p_align_ = 0;
this->offset_ = 0;
this->filesz_ = 0;
return;
}
const Output_data* first;
if (this->output_data_.empty())
first = this->output_bss_.front();
else
first = this->output_data_.front();
this->vaddr_ = first->address();
this->paddr_ = (first->has_load_address()
? first->load_address()
: this->vaddr_);
this->are_addresses_set_ = true;
this->offset_ = first->offset();
if (this->output_data_.empty())
this->filesz_ = 0;
else
{
const Output_data* last_data = this->output_data_.back();
this->filesz_ = (last_data->address()
+ last_data->data_size()
- this->vaddr_);
}
const Output_data* last;
if (this->output_bss_.empty())
last = this->output_data_.back();
else
last = this->output_bss_.back();
this->memsz_ = (last->address()
+ last->data_size()
- this->vaddr_);
this->filesz_ += increase;
this->memsz_ += increase;
// If this is a TLS segment, align the memory size. The code in
// set_section_list ensures that the section after the TLS segment
// is aligned to give us room.
if (this->type_ == elfcpp::PT_TLS)
{
uint64_t segment_align = this->maximum_alignment();
gold_assert(this->vaddr_ == align_address(this->vaddr_, segment_align));
this->memsz_ = align_address(this->memsz_, segment_align);
}
}
// Set the TLS offsets of the sections in the PT_TLS segment.
void
Output_segment::set_tls_offsets()
{
gold_assert(this->type_ == elfcpp::PT_TLS);
for (Output_data_list::iterator p = this->output_data_.begin();
p != this->output_data_.end();
++p)
(*p)->set_tls_offset(this->vaddr_);
for (Output_data_list::iterator p = this->output_bss_.begin();
p != this->output_bss_.end();
++p)
(*p)->set_tls_offset(this->vaddr_);
}
// Return the address of the first section.
uint64_t
Output_segment::first_section_load_address() const
{
for (Output_data_list::const_iterator p = this->output_data_.begin();
p != this->output_data_.end();
++p)
if ((*p)->is_section())
return (*p)->has_load_address() ? (*p)->load_address() : (*p)->address();
for (Output_data_list::const_iterator p = this->output_bss_.begin();
p != this->output_bss_.end();
++p)
if ((*p)->is_section())
return (*p)->has_load_address() ? (*p)->load_address() : (*p)->address();
gold_unreachable();
}
// Return the number of Output_sections in an Output_segment.
unsigned int
Output_segment::output_section_count() const
{
return (this->output_section_count_list(&this->output_data_)
+ this->output_section_count_list(&this->output_bss_));
}
// Return the number of Output_sections in an Output_data_list.
unsigned int
Output_segment::output_section_count_list(const Output_data_list* pdl) const
{
unsigned int count = 0;
for (Output_data_list::const_iterator p = pdl->begin();
p != pdl->end();
++p)
{
if ((*p)->is_section())
++count;
}
return count;
}
// Return the section attached to the list segment with the lowest
// load address. This is used when handling a PHDRS clause in a
// linker script.
Output_section*
Output_segment::section_with_lowest_load_address() const
{
Output_section* found = NULL;
uint64_t found_lma = 0;
this->lowest_load_address_in_list(&this->output_data_, &found, &found_lma);
Output_section* found_data = found;
this->lowest_load_address_in_list(&this->output_bss_, &found, &found_lma);
if (found != found_data && found_data != NULL)
{
gold_error(_("nobits section %s may not precede progbits section %s "
"in same segment"),
found->name(), found_data->name());
return NULL;
}
return found;
}
// Look through a list for a section with a lower load address.
void
Output_segment::lowest_load_address_in_list(const Output_data_list* pdl,
Output_section** found,
uint64_t* found_lma) const
{
for (Output_data_list::const_iterator p = pdl->begin();
p != pdl->end();
++p)
{
if (!(*p)->is_section())
continue;
Output_section* os = static_cast<Output_section*>(*p);
uint64_t lma = (os->has_load_address()
? os->load_address()
: os->address());
if (*found == NULL || lma < *found_lma)
{
*found = os;
*found_lma = lma;
}
}
}
// Write the segment data into *OPHDR.
template<int size, bool big_endian>
void
Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr)
{
ophdr->put_p_type(this->type_);
ophdr->put_p_offset(this->offset_);
ophdr->put_p_vaddr(this->vaddr_);
ophdr->put_p_paddr(this->paddr_);
ophdr->put_p_filesz(this->filesz_);
ophdr->put_p_memsz(this->memsz_);
ophdr->put_p_flags(this->flags_);
ophdr->put_p_align(std::max(this->min_p_align_, this->maximum_alignment()));
}
// Write the section headers into V.
template<int size, bool big_endian>
unsigned char*
Output_segment::write_section_headers(const Layout* layout,
const Stringpool* secnamepool,
unsigned char* v,
unsigned int *pshndx) const
{
// Every section that is attached to a segment must be attached to a
// PT_LOAD segment, so we only write out section headers for PT_LOAD
// segments.
if (this->type_ != elfcpp::PT_LOAD)
return v;
v = this->write_section_headers_list<size, big_endian>(layout, secnamepool,
&this->output_data_,
v, pshndx);
v = this->write_section_headers_list<size, big_endian>(layout, secnamepool,
&this->output_bss_,
v, pshndx);
return v;
}
template<int size, bool big_endian>
unsigned char*
Output_segment::write_section_headers_list(const Layout* layout,
const Stringpool* secnamepool,
const Output_data_list* pdl,
unsigned char* v,
unsigned int* pshndx) const
{
const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
for (Output_data_list::const_iterator p = pdl->begin();
p != pdl->end();
++p)
{
if ((*p)->is_section())
{
const Output_section* ps = static_cast<const Output_section*>(*p);
gold_assert(*pshndx == ps->out_shndx());
elfcpp::Shdr_write<size, big_endian> oshdr(v);
ps->write_header(layout, secnamepool, &oshdr);
v += shdr_size;
++*pshndx;
}
}
return v;
}
// Print the output sections to the map file.
void
Output_segment::print_sections_to_mapfile(Mapfile* mapfile) const
{
if (this->type() != elfcpp::PT_LOAD)
return;
this->print_section_list_to_mapfile(mapfile, &this->output_data_);
this->print_section_list_to_mapfile(mapfile, &this->output_bss_);
}
// Print an output section list to the map file.
void
Output_segment::print_section_list_to_mapfile(Mapfile* mapfile,
const Output_data_list* pdl) const
{
for (Output_data_list::const_iterator p = pdl->begin();
p != pdl->end();
++p)
(*p)->print_to_mapfile(mapfile);
}
// Output_file methods.
Output_file::Output_file(const char* name)
: name_(name),
o_(-1),
file_size_(0),
base_(NULL),
map_is_anonymous_(false),
is_temporary_(false)
{
}
// Try to open an existing file. Returns false if the file doesn't
// exist, has a size of 0 or can't be mmapped.
bool
Output_file::open_for_modification()
{
// The name "-" means "stdout".
if (strcmp(this->name_, "-") == 0)
return false;
// Don't bother opening files with a size of zero.
struct stat s;
if (::stat(this->name_, &s) != 0 || s.st_size == 0)
return false;
int o = open_descriptor(-1, this->name_, O_RDWR, 0);
if (o < 0)
gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
this->o_ = o;
this->file_size_ = s.st_size;
// If the file can't be mmapped, copying the content to an anonymous
// map will probably negate the performance benefits of incremental
// linking. This could be helped by using views and loading only
// the necessary parts, but this is not supported as of now.
if (!this->map_no_anonymous())
{
release_descriptor(o, true);
this->o_ = -1;
this->file_size_ = 0;
return false;
}
return true;
}
// Open the output file.
void
Output_file::open(off_t file_size)
{
this->file_size_ = file_size;
// Unlink the file first; otherwise the open() may fail if the file
// is busy (e.g. it's an executable that's currently being executed).
//
// However, the linker may be part of a system where a zero-length
// file is created for it to write to, with tight permissions (gcc
// 2.95 did something like this). Unlinking the file would work
// around those permission controls, so we only unlink if the file
// has a non-zero size. We also unlink only regular files to avoid
// trouble with directories/etc.
//
// If we fail, continue; this command is merely a best-effort attempt
// to improve the odds for open().
// We let the name "-" mean "stdout"
if (!this->is_temporary_)
{
if (strcmp(this->name_, "-") == 0)
this->o_ = STDOUT_FILENO;
else
{
struct stat s;
if (::stat(this->name_, &s) == 0
&& (S_ISREG (s.st_mode) || S_ISLNK (s.st_mode)))
{
if (s.st_size != 0)
::unlink(this->name_);
else if (!parameters->options().relocatable())
{
// If we don't unlink the existing file, add execute
// permission where read permissions already exist
// and where the umask permits.
int mask = ::umask(0);
::umask(mask);
s.st_mode |= (s.st_mode & 0444) >> 2;
::chmod(this->name_, s.st_mode & ~mask);
}
}
int mode = parameters->options().relocatable() ? 0666 : 0777;
int o = open_descriptor(-1, this->name_, O_RDWR | O_CREAT | O_TRUNC,
mode);
if (o < 0)
gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
this->o_ = o;
}
}
this->map();
}
// Resize the output file.
void
Output_file::resize(off_t file_size)
{
// If the mmap is mapping an anonymous memory buffer, this is easy:
// just mremap to the new size. If it's mapping to a file, we want
// to unmap to flush to the file, then remap after growing the file.
if (this->map_is_anonymous_)
{
void* base = ::mremap(this->base_, this->file_size_, file_size,
MREMAP_MAYMOVE);
if (base == MAP_FAILED)
gold_fatal(_("%s: mremap: %s"), this->name_, strerror(errno));
this->base_ = static_cast<unsigned char*>(base);
this->file_size_ = file_size;
}
else
{
this->unmap();
this->file_size_ = file_size;
if (!this->map_no_anonymous())
gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
}
}
// Map an anonymous block of memory which will later be written to the
// file. Return whether the map succeeded.
bool
Output_file::map_anonymous()
{
void* base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (base != MAP_FAILED)
{
this->map_is_anonymous_ = true;
this->base_ = static_cast<unsigned char*>(base);
return true;
}
return false;
}
// Map the file into memory. Return whether the mapping succeeded.
bool
Output_file::map_no_anonymous()
{
const int o = this->o_;
// If the output file is not a regular file, don't try to mmap it;
// instead, we'll mmap a block of memory (an anonymous buffer), and
// then later write the buffer to the file.
void* base;
struct stat statbuf;
if (o == STDOUT_FILENO || o == STDERR_FILENO
|| ::fstat(o, &statbuf) != 0
|| !S_ISREG(statbuf.st_mode)
|| this->is_temporary_)
return false;
// Ensure that we have disk space available for the file. If we
// don't do this, it is possible that we will call munmap, close,
// and exit with dirty buffers still in the cache with no assigned
// disk blocks. If the disk is out of space at that point, the
// output file will wind up incomplete, but we will have already
// exited. The alternative to fallocate would be to use fdatasync,
// but that would be a more significant performance hit.
if (::posix_fallocate(o, 0, this->file_size_) < 0)
gold_fatal(_("%s: %s"), this->name_, strerror(errno));
// Map the file into memory.
base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
MAP_SHARED, o, 0);
// The mmap call might fail because of file system issues: the file
// system might not support mmap at all, or it might not support
// mmap with PROT_WRITE.
if (base == MAP_FAILED)
return false;
this->map_is_anonymous_ = false;
this->base_ = static_cast<unsigned char*>(base);
return true;
}
// Map the file into memory.
void
Output_file::map()
{
if (this->map_no_anonymous())
return;
// The mmap call might fail because of file system issues: the file
// system might not support mmap at all, or it might not support
// mmap with PROT_WRITE. I'm not sure which errno values we will
// see in all cases, so if the mmap fails for any reason and we
// don't care about file contents, try for an anonymous map.
if (this->map_anonymous())
return;
gold_fatal(_("%s: mmap: failed to allocate %lu bytes for output file: %s"),
this->name_, static_cast<unsigned long>(this->file_size_),
strerror(errno));
}
// Unmap the file from memory.
void
Output_file::unmap()
{
if (::munmap(this->base_, this->file_size_) < 0)
gold_error(_("%s: munmap: %s"), this->name_, strerror(errno));
this->base_ = NULL;
}
// Close the output file.
void
Output_file::close()
{
// If the map isn't file-backed, we need to write it now.
if (this->map_is_anonymous_ && !this->is_temporary_)
{
size_t bytes_to_write = this->file_size_;
size_t offset = 0;
while (bytes_to_write > 0)
{
ssize_t bytes_written = ::write(this->o_, this->base_ + offset,
bytes_to_write);
if (bytes_written == 0)
gold_error(_("%s: write: unexpected 0 return-value"), this->name_);
else if (bytes_written < 0)
gold_error(_("%s: write: %s"), this->name_, strerror(errno));
else
{
bytes_to_write -= bytes_written;
offset += bytes_written;
}
}
}
this->unmap();
// We don't close stdout or stderr
if (this->o_ != STDOUT_FILENO
&& this->o_ != STDERR_FILENO
&& !this->is_temporary_)
if (::close(this->o_) < 0)
gold_error(_("%s: close: %s"), this->name_, strerror(errno));
this->o_ = -1;
}
// Instantiate the templates we need. We could use the configure
// script to restrict this to only the ones for implemented targets.
#ifdef HAVE_TARGET_32_LITTLE
template
off_t
Output_section::add_input_section<32, false>(
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int shndx,
const char* secname,
const elfcpp::Shdr<32, false>& shdr,
unsigned int reloc_shndx,
bool have_sections_script);
#endif
#ifdef HAVE_TARGET_32_BIG
template
off_t
Output_section::add_input_section<32, true>(
Layout* layout,
Sized_relobj<32, true>* object,
unsigned int shndx,
const char* secname,
const elfcpp::Shdr<32, true>& shdr,
unsigned int reloc_shndx,
bool have_sections_script);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
off_t
Output_section::add_input_section<64, false>(
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int shndx,
const char* secname,
const elfcpp::Shdr<64, false>& shdr,
unsigned int reloc_shndx,
bool have_sections_script);
#endif
#ifdef HAVE_TARGET_64_BIG
template
off_t
Output_section::add_input_section<64, true>(
Layout* layout,
Sized_relobj<64, true>* object,
unsigned int shndx,
const char* secname,
const elfcpp::Shdr<64, true>& shdr,
unsigned int reloc_shndx,
bool have_sections_script);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_reloc<elfcpp::SHT_REL, false, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_reloc<elfcpp::SHT_REL, false, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_reloc<elfcpp::SHT_REL, false, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_reloc<elfcpp::SHT_REL, false, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_reloc<elfcpp::SHT_REL, true, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_reloc<elfcpp::SHT_REL, true, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_reloc<elfcpp::SHT_REL, true, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_reloc<elfcpp::SHT_REL, true, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_reloc<elfcpp::SHT_RELA, false, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_reloc<elfcpp::SHT_RELA, false, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_reloc<elfcpp::SHT_RELA, false, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_reloc<elfcpp::SHT_RELA, false, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_reloc<elfcpp::SHT_RELA, true, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_reloc<elfcpp::SHT_RELA, true, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_reloc<elfcpp::SHT_RELA, true, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_reloc<elfcpp::SHT_RELA, true, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_data_reloc<elfcpp::SHT_REL, false, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_data_reloc<elfcpp::SHT_REL, false, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_data_reloc<elfcpp::SHT_REL, false, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_data_reloc<elfcpp::SHT_REL, false, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_data_reloc<elfcpp::SHT_REL, true, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_data_reloc<elfcpp::SHT_REL, true, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_data_reloc<elfcpp::SHT_REL, true, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_data_reloc<elfcpp::SHT_REL, true, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_data_reloc<elfcpp::SHT_RELA, false, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_data_reloc<elfcpp::SHT_RELA, false, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_data_reloc<elfcpp::SHT_RELA, false, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_data_reloc<elfcpp::SHT_RELA, false, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_data_reloc<elfcpp::SHT_RELA, true, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_data_reloc<elfcpp::SHT_RELA, true, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_data_reloc<elfcpp::SHT_RELA, true, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_data_reloc<elfcpp::SHT_RELA, true, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_relocatable_relocs<elfcpp::SHT_REL, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_relocatable_relocs<elfcpp::SHT_REL, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_relocatable_relocs<elfcpp::SHT_REL, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_relocatable_relocs<elfcpp::SHT_REL, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_relocatable_relocs<elfcpp::SHT_RELA, 32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_relocatable_relocs<elfcpp::SHT_RELA, 32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_relocatable_relocs<elfcpp::SHT_RELA, 64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_relocatable_relocs<elfcpp::SHT_RELA, 64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_data_group<32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_data_group<32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_data_group<64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_data_group<64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Output_data_got<32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Output_data_got<32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Output_data_got<64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Output_data_got<64, true>;
#endif
} // End namespace gold.
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