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binutils-gdb/gold/output.cc
Ian Lance Taylor 661be1e21e * layout.cc (Layout::set_segment_offsets): Align the file offset 
to the segment aligment for -N or -n with no load segment.
	* output.cc (Output_segment::add_output_section): Don't crash if
	the first section is a TLS section.
	(Output_segment::set_section_list_addresses): Print an error
	message if the address moves backward in a linker script.
	* script-sections.cc
	(Output_section_element_input::set_section_addresses): Don't
	increase *dot_value for a SHF_TLS/SHT_NOBITS section.
	(Orphan_output_section::set_section_addresses): Likewise.
2009-10-16 05:00:29 +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);
oshdr.put_sh_info(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());
// FIXME: The target needs to set the flags.
oehdr.put_e_flags(0);
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);
oehdr.put_e_phnum(this->segment_header_->data_size()
/ elfcpp::Elf_sizes<size>::phdr_size);
}
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)
: address_(address), local_sym_index_(GSYM_CODE), type_(type),
is_relative_(is_relative), 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)
: address_(address), local_sym_index_(GSYM_CODE), type_(type),
is_relative_(is_relative), 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_section_symbol)
: address_(address), local_sym_index_(local_sym_index), type_(type),
is_relative_(is_relative), 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_section_symbol)
: address_(address), local_sym_index_(local_sym_index), type_(type),
is_relative_(is_relative), 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_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_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();
}
// 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_relative_)
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 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;
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 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_ != INVALID_CODE
&& 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->is_relative_ ? 0 : 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_ != INVALID_CODE
&& !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_relative())
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();
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_.rbegin()->tag() != elfcpp::DT_NULL)
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();
}
// 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),
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_small_section_(false),
is_large_section_(false),
tls_offset_(0),
checkpoint_(NULL),
merge_section_map_(),
merge_section_by_properties_map_(),
relaxed_input_section_map_(),
is_relaxed_input_section_map_valid_(true),
generate_code_fills_at_write_(false)
{
// 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->entsize_ == 0)
this->entsize_ = v;
else
gold_assert(this->entsize_ == v);
}
// 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(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();
this->update_flags_for_input_section(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;
}
// 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)
{
if (this->add_merge_input_section(object, shndx, sh_flags,
entsize, addralign))
{
// 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));
}
}
this->set_current_data_size_for_child(aligned_offset_in_section
+ shdr.get_sh_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 (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())
this->input_sections_.push_back(Input_section(object, shndx,
shdr.get_sh_size(),
addralign));
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->is_relaxed_input_section_map_valid_)
{
Input_section_specifier iss(poris->relobj(), poris->shndx());
this->relaxed_input_section_map_[iss] = 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 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.
Merge_section_properties msp(is_string, entsize, addralign);
Merge_section_by_properties_map::const_iterator p =
this->merge_section_by_properties_map_.find(msp);
if (p != this->merge_section_by_properties_map_.end())
{
Output_merge_base* merge_section = p->second;
merge_section->add_input_section(object, shndx);
gold_assert(merge_section->is_string() == is_string
&& merge_section->entsize() == entsize
&& merge_section->addralign() == addralign);
// Link input section to found merge section.
Input_section_specifier iss(object, shndx);
this->merge_section_map_[iss] = merge_section;
return true;
}
// We handle the actual constant merging in Output_merge_data or
// Output_merge_string_data.
Output_merge_base* pomb;
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;
}
}
// Add new merge section to this output section and link merge section
// properties to new merge section in map.
this->add_output_merge_section(pomb, is_string, entsize);
this->merge_section_by_properties_map_[msp] = pomb;
// Add input section to new merge section and link input section to new
// merge section in map.
pomb->add_input_section(object, shndx);
Input_section_specifier iss(object, shndx);
this->merge_section_map_[iss] = pomb;
return true;
}
// 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())
{
Input_section_specifier iss(is.relobj(), is.shndx());
(*relaxation_map)[iss] = i;
}
}
}
// Convert regular input sections in INPUT_SECTIONS into relaxed input
// sections in RELAXED_SECTIONS. MAP is a prebuilt map from input section
// specifier to 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];
Input_section_specifier iss(poris->relobj(), poris->shndx());
Relaxation_map::const_iterator p = map.find(iss);
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 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));
}
// 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
{
Input_section_specifier iss(object, shndx);
Output_section_data_by_input_section_map::const_iterator p =
this->merge_section_map_.find(iss);
if (p != this->merge_section_map_.end())
{
Output_section_data* posd = p->second;
gold_assert(posd->is_merge_section_for(object, shndx));
return posd;
}
else
return NULL;
}
// Find an relaxed input section corresponding to an input section
// in OBJECT with index SHNDX.
const Output_section_data*
Output_section::find_relaxed_input_section(const Relobj* object,
unsigned int shndx) const
{
// Be careful that the map may not be valid due to input section export
// to scripts or a check-point restore.
if (!this->is_relaxed_input_section_map_valid_)
{
// Rebuild the map as needed.
this->relaxed_input_section_map_.clear();
for (Input_section_list::const_iterator p = this->input_sections_.begin();
p != this->input_sections_.end();
++p)
if (p->is_relaxed_input_section())
{
Input_section_specifier iss(p->relobj(), p->shndx());
this->relaxed_input_section_map_[iss] =
p->relaxed_input_section();
}
this->is_relaxed_input_section_map_valid_ = true;
}
Input_section_specifier iss(object, shndx);
Output_section_data_by_input_section_map::const_iterator p =
this->relaxed_input_section_map_.find(iss);
if (p != this->relaxed_input_section_map_.end())
return p->second;
else
return NULL;
}
// 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->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.
if ((this->flags_ & elfcpp::SHF_ALLOC) == 0)
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)
: 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_)
{
// 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);
}
// 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;
}
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.
// The GNU linker does this for all but .init_array sections; until
// further notice we'll assume that that is an mistake.
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;
// 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();
}
// 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));
// Sort the input sections.
std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_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());
// 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<Simple_input_section>* input_sections)
{
if (this->checkpoint_ != NULL
&& !this->checkpoint_->input_sections_saved())
this->checkpoint_->save_input_sections();
// Invalidate the relaxed input section map.
this->is_relaxed_input_section_map_valid_ = false;
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())
input_sections->push_back(Simple_input_section(p->relobj(),
p->shndx()));
else if (p->is_relaxed_input_section())
input_sections->push_back(
Simple_input_section(p->relaxed_input_section()));
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 an input section from a script.
void
Output_section::add_input_section_for_script(const Simple_input_section& sis,
off_t data_size,
uint64_t 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);
Input_section is =
(sis.is_relaxed_input_section()
? Input_section(sis.relaxed_input_section())
: Input_section(sis.relobj(), sis.shndx(), data_size, addralign));
this->input_sections_.push_back(is);
}
//
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::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 relaxed input section map since we do not keep
// track of it.
this->is_relaxed_input_section_map_valid_ = 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)
{
}
// Add an Output_section to an Output_segment.
void
Output_segment::add_output_section(Output_section* os,
elfcpp::Elf_Word seg_flags)
{
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());
// Update the segment flags.
this->flags_ |= seg_flags;
Output_segment::Output_data_list* pdl;
if (os->type() == elfcpp::SHT_NOBITS)
pdl = &this->output_bss_;
else
pdl = &this->output_data_;
// So that PT_NOTE segments will work correctly, we need to ensure
// that all SHT_NOTE sections are adjacent. This will normally
// happen automatically, because all the SHT_NOTE input sections
// will wind up in the same output section. However, it is possible
// for multiple SHT_NOTE input sections to have different section
// flags, and thus be in different output sections, but for the
// different section flags to map into the same segment flags and
// thus the same output segment.
// 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. This loop is expected to be fast.
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.
}
// For the PT_GNU_RELRO segment, we need to group relro sections,
// and we need to put them before any non-relro sections. Also,
// relro local sections go before relro non-local sections.
if (parameters->options().relro() && 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()))
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();
}
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 is not 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;
// If -z relro is in effect, and the first section in this
// segment is a relro section, then the segment must be aligned
// to at least the common page size. This ensures that the
// PT_GNU_RELRO segment will start at a page boundary.
if (this->type_ == elfcpp::PT_LOAD
&& parameters->options().relro()
&& this->is_first_section_relro())
{
addralign = parameters->target().common_pagesize();
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, off_t* poff,
unsigned int* pshndx)
{
gold_assert(this->type_ == elfcpp::PT_LOAD);
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;
bool in_relro = (parameters->options().relro()
&& this->is_first_section_relro());
off_t orig_off = *poff;
this->offset_ = orig_off;
addr = this->set_section_list_addresses(layout, reset, &this->output_data_,
addr, poff, pshndx, &in_tls,
&in_relro);
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, &in_relro);
// 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);
}
// If all the sections were relro sections, align upward to the
// common page size.
if (in_relro)
{
uint64_t page_align = parameters->target().common_pagesize();
*poff = align_address(*poff, page_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, bool* in_relro)
{
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;
}
}
// If this is a non-relro section after a relro section,
// align it to a common page boundary so that the dynamic
// linker has a page to mark as read-only.
if (*in_relro
&& (!(*p)->is_section()
|| !(*p)->output_section()->is_relro()))
{
uint64_t page_align = parameters->target().common_pagesize();
if (page_align > align)
align = page_align;
*in_relro = 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();
if (os == NULL)
gold_error(_("dot moves backward in linker script "
"from 0x%llx to 0x%llx"),
addr + (off - startoff), (*p)->address());
else
gold_error(_("address of section '%s' moves backward "
"from 0x%llx to 0x%llx"),
os->name(), addr + (off - startoff),
(*p)->address());
}
}
(*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.
void
Output_segment::set_offset()
{
gold_assert(this->type_ != elfcpp::PT_LOAD);
gold_assert(!this->are_addresses_set_);
if (this->output_data_.empty() && this->output_bss_.empty())
{
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_);
// 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);
}
// If this is a RELRO segment, align the memory size. The code in
// set_section_list ensures that the section after the RELRO segment
// is aligned to give us room.
if (this->type_ == elfcpp::PT_GNU_RELRO)
{
uint64_t page_align = parameters->target().common_pagesize();
gold_assert(this->vaddr_ == align_address(this->vaddr_, page_align));
this->memsz_ = align_address(this->memsz_, page_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>(
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>(
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>(
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>(
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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