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// object.cc -- support for an object file for linking in gold
// Copyright (C) 2006-2016 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 <cerrno>
#include <cstring>
#include <cstdarg>
#include "demangle.h"
#include "libiberty.h"
#include "gc.h"
#include "target-select.h"
#include "dwarf_reader.h"
#include "layout.h"
#include "output.h"
#include "symtab.h"
#include "cref.h"
#include "reloc.h"
#include "object.h"
#include "dynobj.h"
#include "plugin.h"
#include "compressed_output.h"
#include "incremental.h"
#include "merge.h"
namespace gold
{
// Struct Read_symbols_data.
// Destroy any remaining File_view objects and buffers of decompressed
// sections.
Read_symbols_data::~Read_symbols_data()
{
if (this->section_headers != NULL)
delete this->section_headers;
if (this->section_names != NULL)
delete this->section_names;
if (this->symbols != NULL)
delete this->symbols;
if (this->symbol_names != NULL)
delete this->symbol_names;
if (this->versym != NULL)
delete this->versym;
if (this->verdef != NULL)
delete this->verdef;
if (this->verneed != NULL)
delete this->verneed;
}
// Class Xindex.
// Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
// section and read it in. SYMTAB_SHNDX is the index of the symbol
// table we care about.
template<int size, bool big_endian>
void
Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
{
if (!this->symtab_xindex_.empty())
return;
gold_assert(symtab_shndx != 0);
// Look through the sections in reverse order, on the theory that it
// is more likely to be near the end than the beginning.
unsigned int i = object->shnum();
while (i > 0)
{
--i;
if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
&& this->adjust_shndx(object->section_link(i)) == symtab_shndx)
{
this->read_symtab_xindex<size, big_endian>(object, i, NULL);
return;
}
}
object->error(_("missing SHT_SYMTAB_SHNDX section"));
}
// Read in the symtab_xindex_ array, given the section index of the
// SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
// section headers.
template<int size, bool big_endian>
void
Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
const unsigned char* pshdrs)
{
section_size_type bytecount;
const unsigned char* contents;
if (pshdrs == NULL)
contents = object->section_contents(xindex_shndx, &bytecount, false);
else
{
const unsigned char* p = (pshdrs
+ (xindex_shndx
* elfcpp::Elf_sizes<size>::shdr_size));
typename elfcpp::Shdr<size, big_endian> shdr(p);
bytecount = convert_to_section_size_type(shdr.get_sh_size());
contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
}
gold_assert(this->symtab_xindex_.empty());
this->symtab_xindex_.reserve(bytecount / 4);
for (section_size_type i = 0; i < bytecount; i += 4)
{
unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
// We preadjust the section indexes we save.
this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
}
}
// Symbol symndx has a section of SHN_XINDEX; return the real section
// index.
unsigned int
Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
{
if (symndx >= this->symtab_xindex_.size())
{
object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
symndx);
return elfcpp::SHN_UNDEF;
}
unsigned int shndx = this->symtab_xindex_[symndx];
if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
{
object->error(_("extended index for symbol %u out of range: %u"),
symndx, shndx);
return elfcpp::SHN_UNDEF;
}
return shndx;
}
// Class Object.
// Report an error for this object file. This is used by the
// elfcpp::Elf_file interface, and also called by the Object code
// itself.
void
Object::error(const char* format, ...) const
{
va_list args;
va_start(args, format);
char* buf = NULL;
if (vasprintf(&buf, format, args) < 0)
gold_nomem();
va_end(args);
gold_error(_("%s: %s"), this->name().c_str(), buf);
free(buf);
}
// Return a view of the contents of a section.
const unsigned char*
Object::section_contents(unsigned int shndx, section_size_type* plen,
bool cache)
{ return this->do_section_contents(shndx, plen, cache); }
// Read the section data into SD. This is code common to Sized_relobj_file
// and Sized_dynobj, so we put it into Object.
template<int size, bool big_endian>
void
Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
Read_symbols_data* sd)
{
const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
// Read the section headers.
const off_t shoff = elf_file->shoff();
const unsigned int shnum = this->shnum();
sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
true, true);
// Read the section names.
const unsigned char* pshdrs = sd->section_headers->data();
const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
this->error(_("section name section has wrong type: %u"),
static_cast<unsigned int>(shdrnames.get_sh_type()));
sd->section_names_size =
convert_to_section_size_type(shdrnames.get_sh_size());
sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
sd->section_names_size, false,
false);
}
// If NAME is the name of a special .gnu.warning section, arrange for
// the warning to be issued. SHNDX is the section index. Return
// whether it is a warning section.
bool
Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
Symbol_table* symtab)
{
const char warn_prefix[] = ".gnu.warning.";
const int warn_prefix_len = sizeof warn_prefix - 1;
if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
{
// Read the section contents to get the warning text. It would
// be nicer if we only did this if we have to actually issue a
// warning. Unfortunately, warnings are issued as we relocate
// sections. That means that we can not lock the object then,
// as we might try to issue the same warning multiple times
// simultaneously.
section_size_type len;
const unsigned char* contents = this->section_contents(shndx, &len,
false);
if (len == 0)
{
const char* warning = name + warn_prefix_len;
contents = reinterpret_cast<const unsigned char*>(warning);
len = strlen(warning);
}
std::string warning(reinterpret_cast<const char*>(contents), len);
symtab->add_warning(name + warn_prefix_len, this, warning);
return true;
}
return false;
}
// If NAME is the name of the special section which indicates that
// this object was compiled with -fsplit-stack, mark it accordingly.
bool
Object::handle_split_stack_section(const char* name)
{
if (strcmp(name, ".note.GNU-split-stack") == 0)
{
this->uses_split_stack_ = true;
return true;
}
if (strcmp(name, ".note.GNU-no-split-stack") == 0)
{
this->has_no_split_stack_ = true;
return true;
}
return false;
}
// Class Relobj
template<int size>
void
Relobj::initialize_input_to_output_map(unsigned int shndx,
typename elfcpp::Elf_types<size>::Elf_Addr starting_address,
Unordered_map<section_offset_type,
typename elfcpp::Elf_types<size>::Elf_Addr>* output_addresses) const {
Object_merge_map *map = this->object_merge_map_;
map->initialize_input_to_output_map<size>(shndx, starting_address,
output_addresses);
}
void
Relobj::add_merge_mapping(Output_section_data *output_data,
unsigned int shndx, section_offset_type offset,
section_size_type length,
section_offset_type output_offset) {
Object_merge_map* object_merge_map = this->get_or_create_merge_map();
object_merge_map->add_mapping(output_data, shndx, offset, length, output_offset);
}
bool
Relobj::merge_output_offset(unsigned int shndx, section_offset_type offset,
section_offset_type *poutput) const {
Object_merge_map* object_merge_map = this->object_merge_map_;
if (object_merge_map == NULL)
return false;
return object_merge_map->get_output_offset(shndx, offset, poutput);
}
const Output_section_data*
Relobj::find_merge_section(unsigned int shndx) const {
Object_merge_map* object_merge_map = this->object_merge_map_;
if (object_merge_map == NULL)
return NULL;
return object_merge_map->find_merge_section(shndx);
}
// To copy the symbols data read from the file to a local data structure.
// This function is called from do_layout only while doing garbage
// collection.
void
Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
unsigned int section_header_size)
{
gc_sd->section_headers_data =
new unsigned char[(section_header_size)];
memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
section_header_size);
gc_sd->section_names_data =
new unsigned char[sd->section_names_size];
memcpy(gc_sd->section_names_data, sd->section_names->data(),
sd->section_names_size);
gc_sd->section_names_size = sd->section_names_size;
if (sd->symbols != NULL)
{
gc_sd->symbols_data =
new unsigned char[sd->symbols_size];
memcpy(gc_sd->symbols_data, sd->symbols->data(),
sd->symbols_size);
}
else
{
gc_sd->symbols_data = NULL;
}
gc_sd->symbols_size = sd->symbols_size;
gc_sd->external_symbols_offset = sd->external_symbols_offset;
if (sd->symbol_names != NULL)
{
gc_sd->symbol_names_data =
new unsigned char[sd->symbol_names_size];
memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
sd->symbol_names_size);
}
else
{
gc_sd->symbol_names_data = NULL;
}
gc_sd->symbol_names_size = sd->symbol_names_size;
}
// This function determines if a particular section name must be included
// in the link. This is used during garbage collection to determine the
// roots of the worklist.
bool
Relobj::is_section_name_included(const char* name)
{
if (is_prefix_of(".ctors", name)
|| is_prefix_of(".dtors", name)
|| is_prefix_of(".note", name)
|| is_prefix_of(".init", name)
|| is_prefix_of(".fini", name)
|| is_prefix_of(".gcc_except_table", name)
|| is_prefix_of(".jcr", name)
|| is_prefix_of(".preinit_array", name)
|| (is_prefix_of(".text", name)
&& strstr(name, "personality"))
|| (is_prefix_of(".data", name)
&& strstr(name, "personality"))
|| (is_prefix_of(".sdata", name)
&& strstr(name, "personality"))
|| (is_prefix_of(".gnu.linkonce.d", name)
&& strstr(name, "personality"))
|| (is_prefix_of(".rodata", name)
&& strstr(name, "nptl_version")))
{
return true;
}
return false;
}
// Finalize the incremental relocation information. Allocates a block
// of relocation entries for each symbol, and sets the reloc_bases_
// array to point to the first entry in each block. If CLEAR_COUNTS
// is TRUE, also clear the per-symbol relocation counters.
void
Relobj::finalize_incremental_relocs(Layout* layout, bool clear_counts)
{
unsigned int nsyms = this->get_global_symbols()->size();
this->reloc_bases_ = new unsigned int[nsyms];
gold_assert(this->reloc_bases_ != NULL);
gold_assert(layout->incremental_inputs() != NULL);
unsigned int rindex = layout->incremental_inputs()->get_reloc_count();
for (unsigned int i = 0; i < nsyms; ++i)
{
this->reloc_bases_[i] = rindex;
rindex += this->reloc_counts_[i];
if (clear_counts)
this->reloc_counts_[i] = 0;
}
layout->incremental_inputs()->set_reloc_count(rindex);
}
Object_merge_map*
Relobj::get_or_create_merge_map()
{
if (!this->object_merge_map_)
this->object_merge_map_ = new Object_merge_map();
return this->object_merge_map_;
}
// Class Sized_relobj.
// Iterate over local symbols, calling a visitor class V for each GOT offset
// associated with a local symbol.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_for_all_local_got_entries(
Got_offset_list::Visitor* v) const
{
unsigned int nsyms = this->local_symbol_count();
for (unsigned int i = 0; i < nsyms; i++)
{
Local_got_entry_key key(i, 0);
Local_got_offsets::const_iterator p = this->local_got_offsets_.find(key);
if (p != this->local_got_offsets_.end())
{
const Got_offset_list* got_offsets = p->second;
got_offsets->for_all_got_offsets(v);
}
}
}
// Get the address of an output section.
template<int size, bool big_endian>
uint64_t
Sized_relobj<size, big_endian>::do_output_section_address(
unsigned int shndx)
{
// If the input file is linked as --just-symbols, the output
// section address is the input section address.
if (this->just_symbols())
return this->section_address(shndx);
const Output_section* os = this->do_output_section(shndx);
gold_assert(os != NULL);
return os->address();
}
// Class Sized_relobj_file.
template<int size, bool big_endian>
Sized_relobj_file<size, big_endian>::Sized_relobj_file(
const std::string& name,
Input_file* input_file,
off_t offset,
const elfcpp::Ehdr<size, big_endian>& ehdr)
: Sized_relobj<size, big_endian>(name, input_file, offset),
elf_file_(this, ehdr),
symtab_shndx_(-1U),
local_symbol_count_(0),
output_local_symbol_count_(0),
output_local_dynsym_count_(0),
symbols_(),
defined_count_(0),
local_symbol_offset_(0),
local_dynsym_offset_(0),
local_values_(),
local_plt_offsets_(),
kept_comdat_sections_(),
has_eh_frame_(false),
discarded_eh_frame_shndx_(-1U),
is_deferred_layout_(false),
deferred_layout_(),
deferred_layout_relocs_(),
output_views_(NULL)
{
this->e_type_ = ehdr.get_e_type();
}
template<int size, bool big_endian>
Sized_relobj_file<size, big_endian>::~Sized_relobj_file()
{
}
// Set up an object file based on the file header. This sets up the
// section information.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_setup()
{
const unsigned int shnum = this->elf_file_.shnum();
this->set_shnum(shnum);
}
// Find the SHT_SYMTAB section, given the section headers. The ELF
// standard says that maybe in the future there can be more than one
// SHT_SYMTAB section. Until somebody figures out how that could
// work, we assume there is only one.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::find_symtab(const unsigned char* pshdrs)
{
const unsigned int shnum = this->shnum();
this->symtab_shndx_ = 0;
if (shnum > 0)
{
// Look through the sections in reverse order, since gas tends
// to put the symbol table at the end.
const unsigned char* p = pshdrs + shnum * This::shdr_size;
unsigned int i = shnum;
unsigned int xindex_shndx = 0;
unsigned int xindex_link = 0;
while (i > 0)
{
--i;
p -= This::shdr_size;
typename This::Shdr shdr(p);
if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
{
this->symtab_shndx_ = i;
if (xindex_shndx > 0 && xindex_link == i)
{
Xindex* xindex =
new Xindex(this->elf_file_.large_shndx_offset());
xindex->read_symtab_xindex<size, big_endian>(this,
xindex_shndx,
pshdrs);
this->set_xindex(xindex);
}
break;
}
// Try to pick up the SHT_SYMTAB_SHNDX section, if there is
// one. This will work if it follows the SHT_SYMTAB
// section.
if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
{
xindex_shndx = i;
xindex_link = this->adjust_shndx(shdr.get_sh_link());
}
}
}
}
// Return the Xindex structure to use for object with lots of
// sections.
template<int size, bool big_endian>
Xindex*
Sized_relobj_file<size, big_endian>::do_initialize_xindex()
{
gold_assert(this->symtab_shndx_ != -1U);
Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
return xindex;
}
// Return whether SHDR has the right type and flags to be a GNU
// .eh_frame section.
template<int size, bool big_endian>
bool
Sized_relobj_file<size, big_endian>::check_eh_frame_flags(
const elfcpp::Shdr<size, big_endian>* shdr) const
{
elfcpp::Elf_Word sh_type = shdr->get_sh_type();
return ((sh_type == elfcpp::SHT_PROGBITS
|| sh_type == elfcpp::SHT_X86_64_UNWIND)
&& (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
}
// Find the section header with the given name.
template<int size, bool big_endian>
const unsigned char*
Object::find_shdr(
const unsigned char* pshdrs,
const char* name,
const char* names,
section_size_type names_size,
const unsigned char* hdr) const
{
const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
const unsigned int shnum = this->shnum();
const unsigned char* hdr_end = pshdrs + shdr_size * shnum;
size_t sh_name = 0;
while (1)
{
if (hdr)
{
// We found HDR last time we were called, continue looking.
typename elfcpp::Shdr<size, big_endian> shdr(hdr);
sh_name = shdr.get_sh_name();
}
else
{
// Look for the next occurrence of NAME in NAMES.
// The fact that .shstrtab produced by current GNU tools is
// string merged means we shouldn't have both .not.foo and
// .foo in .shstrtab, and multiple .foo sections should all
// have the same sh_name. However, this is not guaranteed
// by the ELF spec and not all ELF object file producers may
// be so clever.
size_t len = strlen(name) + 1;
const char *p = sh_name ? names + sh_name + len : names;
p = reinterpret_cast<const char*>(memmem(p, names_size - (p - names),
name, len));
if (p == NULL)
return NULL;
sh_name = p - names;
hdr = pshdrs;
if (sh_name == 0)
return hdr;
}
hdr += shdr_size;
while (hdr < hdr_end)
{
typename elfcpp::Shdr<size, big_endian> shdr(hdr);
if (shdr.get_sh_name() == sh_name)
return hdr;
hdr += shdr_size;
}
hdr = NULL;
if (sh_name == 0)
return hdr;
}
}
// Return whether there is a GNU .eh_frame section, given the section
// headers and the section names.
template<int size, bool big_endian>
bool
Sized_relobj_file<size, big_endian>::find_eh_frame(
const unsigned char* pshdrs,
const char* names,
section_size_type names_size) const
{
const unsigned char* s = NULL;
while (1)
{
s = this->template find_shdr<size, big_endian>(pshdrs, ".eh_frame",
names, names_size, s);
if (s == NULL)
return false;
typename This::Shdr shdr(s);
if (this->check_eh_frame_flags(&shdr))
return true;
}
}
// Return TRUE if this is a section whose contents will be needed in the
// Add_symbols task. This function is only called for sections that have
// already passed the test in is_compressed_debug_section() and the debug
// section name prefix, ".debug"/".zdebug", has been skipped.
static bool
need_decompressed_section(const char* name)
{
if (*name++ != '_')
return false;
#ifdef ENABLE_THREADS
// Decompressing these sections now will help only if we're
// multithreaded.
if (parameters->options().threads())
{
// We will need .zdebug_str if this is not an incremental link
// (i.e., we are processing string merge sections) or if we need
// to build a gdb index.
if ((!parameters->incremental() || parameters->options().gdb_index())
&& strcmp(name, "str") == 0)
return true;
// We will need these other sections when building a gdb index.
if (parameters->options().gdb_index()
&& (strcmp(name, "info") == 0
|| strcmp(name, "types") == 0
|| strcmp(name, "pubnames") == 0
|| strcmp(name, "pubtypes") == 0
|| strcmp(name, "ranges") == 0
|| strcmp(name, "abbrev") == 0))
return true;
}
#endif
// Even when single-threaded, we will need .zdebug_str if this is
// not an incremental link and we are building a gdb index.
// Otherwise, we would decompress the section twice: once for
// string merge processing, and once for building the gdb index.
if (!parameters->incremental()
&& parameters->options().gdb_index()
&& strcmp(name, "str") == 0)
return true;
return false;
}
// Build a table for any compressed debug sections, mapping each section index
// to the uncompressed size and (if needed) the decompressed contents.
template<int size, bool big_endian>
Compressed_section_map*
build_compressed_section_map(
const unsigned char* pshdrs,
unsigned int shnum,
const char* names,
section_size_type names_size,
Object* obj,
bool decompress_if_needed)
{
Compressed_section_map* uncompressed_map = new Compressed_section_map();
const unsigned int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
const unsigned char* p = pshdrs + shdr_size;
for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
{
typename elfcpp::Shdr<size, big_endian> shdr(p);
if (shdr.get_sh_type() == elfcpp::SHT_PROGBITS
&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
{
if (shdr.get_sh_name() >= names_size)
{
obj->error(_("bad section name offset for section %u: %lu"),
i, static_cast<unsigned long>(shdr.get_sh_name()));
continue;
}
const char* name = names + shdr.get_sh_name();
bool is_compressed = ((shdr.get_sh_flags()
& elfcpp::SHF_COMPRESSED) != 0);
bool is_zcompressed = (!is_compressed
&& is_compressed_debug_section(name));
if (is_zcompressed || is_compressed)
{
section_size_type len;
const unsigned char* contents =
obj->section_contents(i, &len, false);
uint64_t uncompressed_size;
if (is_zcompressed)
{
// Skip over the ".zdebug" prefix.
name += 7;
uncompressed_size = get_uncompressed_size(contents, len);
}
else
{
// Skip over the ".debug" prefix.
name += 6;
elfcpp::Chdr<size, big_endian> chdr(contents);
uncompressed_size = chdr.get_ch_size();
}
Compressed_section_info info;
info.size = convert_to_section_size_type(uncompressed_size);
info.flag = shdr.get_sh_flags();
info.contents = NULL;
if (uncompressed_size != -1ULL)
{
unsigned char* uncompressed_data = NULL;
if (decompress_if_needed && need_decompressed_section(name))
{
uncompressed_data = new unsigned char[uncompressed_size];
if (decompress_input_section(contents, len,
uncompressed_data,
uncompressed_size,
size, big_endian,
shdr.get_sh_flags()))
info.contents = uncompressed_data;
else
delete[] uncompressed_data;
}
(*uncompressed_map)[i] = info;
}
}
}
}
return uncompressed_map;
}
// Stash away info for a number of special sections.
// Return true if any of the sections found require local symbols to be read.
template<int size, bool big_endian>
bool
Sized_relobj_file<size, big_endian>::do_find_special_sections(
Read_symbols_data* sd)
{
const unsigned char* const pshdrs = sd->section_headers->data();
const unsigned char* namesu = sd->section_names->data();
const char* names = reinterpret_cast<const char*>(namesu);
if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
this->has_eh_frame_ = true;
Compressed_section_map* compressed_sections =
build_compressed_section_map<size, big_endian>(
pshdrs, this->shnum(), names, sd->section_names_size, this, true);
if (compressed_sections != NULL)
this->set_compressed_sections(compressed_sections);
return (this->has_eh_frame_
|| (!parameters->options().relocatable()
&& parameters->options().gdb_index()
&& (memmem(names, sd->section_names_size, "debug_info", 12) == 0
|| memmem(names, sd->section_names_size, "debug_types",
13) == 0)));
}
// Read the sections and symbols from an object file.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
{
this->base_read_symbols(sd);
}
// Read the sections and symbols from an object file. This is common
// code for all target-specific overrides of do_read_symbols().
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::base_read_symbols(Read_symbols_data* sd)
{
this->read_section_data(&this->elf_file_, sd);
const unsigned char* const pshdrs = sd->section_headers->data();
this->find_symtab(pshdrs);
bool need_local_symbols = this->do_find_special_sections(sd);
sd->symbols = NULL;
sd->symbols_size = 0;
sd->external_symbols_offset = 0;
sd->symbol_names = NULL;
sd->symbol_names_size = 0;
if (this->symtab_shndx_ == 0)
{
// No symbol table. Weird but legal.
return;
}
// Get the symbol table section header.
typename This::Shdr symtabshdr(pshdrs
+ this->symtab_shndx_ * This::shdr_size);
gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
// If this object has a .eh_frame section, or if building a .gdb_index
// section and there is debug info, we need all the symbols.
// Otherwise we only need the external symbols. While it would be
// simpler to just always read all the symbols, I've seen object
// files with well over 2000 local symbols, which for a 64-bit
// object file format is over 5 pages that we don't need to read
// now.
const int sym_size = This::sym_size;
const unsigned int loccount = symtabshdr.get_sh_info();
this->local_symbol_count_ = loccount;
this->local_values_.resize(loccount);
section_offset_type locsize = loccount * sym_size;
off_t dataoff = symtabshdr.get_sh_offset();
section_size_type datasize =
convert_to_section_size_type(symtabshdr.get_sh_size());
off_t extoff = dataoff + locsize;
section_size_type extsize = datasize - locsize;
off_t readoff = need_local_symbols ? dataoff : extoff;
section_size_type readsize = need_local_symbols ? datasize : extsize;
if (readsize == 0)
{
// No external symbols. Also weird but also legal.
return;
}
File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
// Read the section header for the symbol names.
unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
if (strtab_shndx >= this->shnum())
{
this->error(_("invalid symbol table name index: %u"), strtab_shndx);
return;
}
typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
{
this->error(_("symbol table name section has wrong type: %u"),
static_cast<unsigned int>(strtabshdr.get_sh_type()));
return;
}
// Read the symbol names.
File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
strtabshdr.get_sh_size(),
false, true);
sd->symbols = fvsymtab;
sd->symbols_size = readsize;
sd->external_symbols_offset = need_local_symbols ? locsize : 0;
sd->symbol_names = fvstrtab;
sd->symbol_names_size =
convert_to_section_size_type(strtabshdr.get_sh_size());
}
// Return the section index of symbol SYM. Set *VALUE to its value in
// the object file. Set *IS_ORDINARY if this is an ordinary section
// index, not a special code between SHN_LORESERVE and SHN_HIRESERVE.
// Note that for a symbol which is not defined in this object file,
// this will set *VALUE to 0 and return SHN_UNDEF; it will not return
// the final value of the symbol in the link.
template<int size, bool big_endian>
unsigned int
Sized_relobj_file<size, big_endian>::symbol_section_and_value(unsigned int sym,
Address* value,
bool* is_ordinary)
{
section_size_type symbols_size;
const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
&symbols_size,
false);
const size_t count = symbols_size / This::sym_size;
gold_assert(sym < count);
elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
*value = elfsym.get_st_value();
return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
}
// Return whether to include a section group in the link. LAYOUT is
// used to keep track of which section groups we have already seen.
// INDEX is the index of the section group and SHDR is the section
// header. If we do not want to include this group, we set bits in
// OMIT for each section which should be discarded.
template<int size, bool big_endian>
bool
Sized_relobj_file<size, big_endian>::include_section_group(
Symbol_table* symtab,
Layout* layout,
unsigned int index,
const char* name,
const unsigned char* shdrs,
const char* section_names,
section_size_type section_names_size,
std::vector<bool>* omit)
{
// Read the section contents.
typename This::Shdr shdr(shdrs + index * This::shdr_size);
const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
shdr.get_sh_size(), true, false);
const elfcpp::Elf_Word* pword =
reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
// The first word contains flags. We only care about COMDAT section
// groups. Other section groups are always included in the link
// just like ordinary sections.
elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
// Look up the group signature, which is the name of a symbol. ELF
// uses a symbol name because some group signatures are long, and
// the name is generally already in the symbol table, so it makes
// sense to put the long string just once in .strtab rather than in
// both .strtab and .shstrtab.
// Get the appropriate symbol table header (this will normally be
// the single SHT_SYMTAB section, but in principle it need not be).
const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
// Read the symbol table entry.
unsigned int symndx = shdr.get_sh_info();
if (symndx >= symshdr.get_sh_size() / This::sym_size)
{
this->error(_("section group %u info %u out of range"),
index, symndx);
return false;
}
off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
false);
elfcpp::Sym<size, big_endian> sym(psym);
// Read the symbol table names.
section_size_type symnamelen;
const unsigned char* psymnamesu;
psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
&symnamelen, true);
const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
// Get the section group signature.
if (sym.get_st_name() >= symnamelen)
{
this->error(_("symbol %u name offset %u out of range"),
symndx, sym.get_st_name());
return false;
}
std::string signature(psymnames + sym.get_st_name());
// It seems that some versions of gas will create a section group
// associated with a section symbol, and then fail to give a name to
// the section symbol. In such a case, use the name of the section.
if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
{
bool is_ordinary;
unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
sym.get_st_shndx(),
&is_ordinary);
if (!is_ordinary || sym_shndx >= this->shnum())
{
this->error(_("symbol %u invalid section index %u"),
symndx, sym_shndx);
return false;
}
typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
if (member_shdr.get_sh_name() < section_names_size)
signature = section_names + member_shdr.get_sh_name();
}
// Record this section group in the layout, and see whether we've already
// seen one with the same signature.
bool include_group;
bool is_comdat;
Kept_section* kept_section = NULL;
if ((flags & elfcpp::GRP_COMDAT) == 0)
{
include_group = true;
is_comdat = false;
}
else
{
include_group = layout->find_or_add_kept_section(signature,
this, index, true,
true, &kept_section);
is_comdat = true;
}
if (is_comdat && include_group)
{
Incremental_inputs* incremental_inputs = layout->incremental_inputs();
if (incremental_inputs != NULL)
incremental_inputs->report_comdat_group(this, signature.c_str());
}
size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
std::vector<unsigned int> shndxes;
bool relocate_group = include_group && parameters->options().relocatable();
if (relocate_group)
shndxes.reserve(count - 1);
for (size_t i = 1; i < count; ++i)
{
elfcpp::Elf_Word shndx =
this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
if (relocate_group)
shndxes.push_back(shndx);
if (shndx >= this->shnum())
{
this->error(_("section %u in section group %u out of range"),
shndx, index);
continue;
}
// Check for an earlier section number, since we're going to get
// it wrong--we may have already decided to include the section.
if (shndx < index)
this->error(_("invalid section group %u refers to earlier section %u"),
index, shndx);
// Get the name of the member section.
typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
if (member_shdr.get_sh_name() >= section_names_size)
{
// This is an error, but it will be diagnosed eventually
// in do_layout, so we don't need to do anything here but
// ignore it.
continue;
}
std::string mname(section_names + member_shdr.get_sh_name());
if (include_group)
{
if (is_comdat)
kept_section->add_comdat_section(mname, shndx,
member_shdr.get_sh_size());
}
else
{
(*omit)[shndx] = true;
if (is_comdat)
{
Relobj* kept_object = kept_section->object();
if (kept_section->is_comdat())
{
// Find the corresponding kept section, and store
// that info in the discarded section table.
unsigned int kept_shndx;
uint64_t kept_size;
if (kept_section->find_comdat_section(mname, &kept_shndx,
&kept_size))
{
// We don't keep a mapping for this section if
// it has a different size. The mapping is only
// used for relocation processing, and we don't
// want to treat the sections as similar if the
// sizes are different. Checking the section
// size is the approach used by the GNU linker.
if (kept_size == member_shdr.get_sh_size())
this->set_kept_comdat_section(shndx, kept_object,
kept_shndx);
}
}
else
{
// The existing section is a linkonce section. Add
// a mapping if there is exactly one section in the
// group (which is true when COUNT == 2) and if it
// is the same size.
if (count == 2
&& (kept_section->linkonce_size()
== member_shdr.get_sh_size()))
this->set_kept_comdat_section(shndx, kept_object,
kept_section->shndx());
}
}
}
}
if (relocate_group)
layout->layout_group(symtab, this, index, name, signature.c_str(),
shdr, flags, &shndxes);
return include_group;
}
// Whether to include a linkonce section in the link. NAME is the
// name of the section and SHDR is the section header.
// Linkonce sections are a GNU extension implemented in the original
// GNU linker before section groups were defined. The semantics are
// that we only include one linkonce section with a given name. The
// name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
// where T is the type of section and SYMNAME is the name of a symbol.
// In an attempt to make linkonce sections interact well with section
// groups, we try to identify SYMNAME and use it like a section group
// signature. We want to block section groups with that signature,
// but not other linkonce sections with that signature. We also use
// the full name of the linkonce section as a normal section group
// signature.
template<int size, bool big_endian>
bool
Sized_relobj_file<size, big_endian>::include_linkonce_section(
Layout* layout,
unsigned int index,
const char* name,
const elfcpp::Shdr<size, big_endian>& shdr)
{
typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
// In general the symbol name we want will be the string following
// the last '.'. However, we have to handle the case of
// .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
// some versions of gcc. So we use a heuristic: if the name starts
// with ".gnu.linkonce.t.", we use everything after that. Otherwise
// we look for the last '.'. We can't always simply skip
// ".gnu.linkonce.X", because we have to deal with cases like
// ".gnu.linkonce.d.rel.ro.local".
const char* const linkonce_t = ".gnu.linkonce.t.";
const char* symname;
if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
symname = name + strlen(linkonce_t);
else
symname = strrchr(name, '.') + 1;
std::string sig1(symname);
std::string sig2(name);
Kept_section* kept1;
Kept_section* kept2;
bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
false, &kept1);
bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
true, &kept2);
if (!include2)
{
// We are not including this section because we already saw the
// name of the section as a signature. This normally implies
// that the kept section is another linkonce section. If it is
// the same size, record it as the section which corresponds to
// this one.
if (kept2->object() != NULL
&& !kept2->is_comdat()
&& kept2->linkonce_size() == sh_size)
this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
}
else if (!include1)
{
// The section is being discarded on the basis of its symbol
// name. This means that the corresponding kept section was
// part of a comdat group, and it will be difficult to identify
// the specific section within that group that corresponds to
// this linkonce section. We'll handle the simple case where
// the group has only one member section. Otherwise, it's not
// worth the effort.
unsigned int kept_shndx;
uint64_t kept_size;
if (kept1->object() != NULL
&& kept1->is_comdat()
&& kept1->find_single_comdat_section(&kept_shndx, &kept_size)
&& kept_size == sh_size)
this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
}
else
{
kept1->set_linkonce_size(sh_size);
kept2->set_linkonce_size(sh_size);
}
return include1 && include2;
}
// Layout an input section.
template<int size, bool big_endian>
inline void
Sized_relobj_file<size, big_endian>::layout_section(
Layout* layout,
unsigned int shndx,
const char* name,
const typename This::Shdr& shdr,
unsigned int reloc_shndx,
unsigned int reloc_type)
{
off_t offset;
Output_section* os = layout->layout(this, shndx, name, shdr,
reloc_shndx, reloc_type, &offset);
this->output_sections()[shndx] = os;
if (offset == -1)
this->section_offsets()[shndx] = invalid_address;
else
this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
// If this section requires special handling, and if there are
// relocs that apply to it, then we must do the special handling
// before we apply the relocs.
if (offset == -1 && reloc_shndx != 0)
this->set_relocs_must_follow_section_writes();
}
// Layout an input .eh_frame section.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
Layout* layout,
const unsigned char* symbols_data,
section_size_type symbols_size,
const unsigned char* symbol_names_data,
section_size_type symbol_names_size,
unsigned int shndx,
const typename This::Shdr& shdr,
unsigned int reloc_shndx,
unsigned int reloc_type)
{
gold_assert(this->has_eh_frame_);
off_t offset;
Output_section* os = layout->layout_eh_frame(this,
symbols_data,
symbols_size,
symbol_names_data,
symbol_names_size,
shndx,
shdr,
reloc_shndx,
reloc_type,
&offset);
this->output_sections()[shndx] = os;
if (os == NULL || offset == -1)
{
// An object can contain at most one section holding exception
// frame information.
gold_assert(this->discarded_eh_frame_shndx_ == -1U);
this->discarded_eh_frame_shndx_ = shndx;
this->section_offsets()[shndx] = invalid_address;
}
else
this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
// If this section requires special handling, and if there are
// relocs that aply to it, then we must do the special handling
// before we apply the relocs.
if (os != NULL && offset == -1 && reloc_shndx != 0)
this->set_relocs_must_follow_section_writes();
}
// Lay out the input sections. We walk through the sections and check
// whether they should be included in the link. If they should, we
// pass them to the Layout object, which will return an output section
// and an offset.
// This function is called twice sometimes, two passes, when mapping
// of input sections to output sections must be delayed.
// This is true for the following :
// * Garbage collection (--gc-sections): Some input sections will be
// discarded and hence the assignment must wait until the second pass.
// In the first pass, it is for setting up some sections as roots to
// a work-list for --gc-sections and to do comdat processing.
// * Identical Code Folding (--icf=<safe,all>): Some input sections
// will be folded and hence the assignment must wait.
// * Using plugins to map some sections to unique segments: Mapping
// some sections to unique segments requires mapping them to unique
// output sections too. This can be done via plugins now and this
// information is not available in the first pass.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
Layout* layout,
Read_symbols_data* sd)
{
const unsigned int shnum = this->shnum();
/* Should this function be called twice? */
bool is_two_pass = (parameters->options().gc_sections()
|| parameters->options().icf_enabled()
|| layout->is_unique_segment_for_sections_specified());
/* Only one of is_pass_one and is_pass_two is true. Both are false when
a two-pass approach is not needed. */
bool is_pass_one = false;
bool is_pass_two = false;
Symbols_data* gc_sd = NULL;
/* Check if do_layout needs to be two-pass. If so, find out which pass
should happen. In the first pass, the data in sd is saved to be used
later in the second pass. */
if (is_two_pass)
{
gc_sd = this->get_symbols_data();
if (gc_sd == NULL)
{
gold_assert(sd != NULL);
is_pass_one = true;
}
else
{
if (parameters->options().gc_sections())
gold_assert(symtab->gc()->is_worklist_ready());
if (parameters->options().icf_enabled())
gold_assert(symtab->icf()->is_icf_ready());
is_pass_two = true;
}
}
if (shnum == 0)
return;
if (is_pass_one)
{
// During garbage collection save the symbols data to use it when
// re-entering this function.
gc_sd = new Symbols_data;
this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
this->set_symbols_data(gc_sd);
}
const unsigned char* section_headers_data = NULL;
section_size_type section_names_size;
const unsigned char* symbols_data = NULL;
section_size_type symbols_size;
const unsigned char* symbol_names_data = NULL;
section_size_type symbol_names_size;
if (is_two_pass)
{
section_headers_data = gc_sd->section_headers_data;
section_names_size = gc_sd->section_names_size;
symbols_data = gc_sd->symbols_data;
symbols_size = gc_sd->symbols_size;
symbol_names_data = gc_sd->symbol_names_data;
symbol_names_size = gc_sd->symbol_names_size;
}
else
{
section_headers_data = sd->section_headers->data();
section_names_size = sd->section_names_size;
if (sd->symbols != NULL)
symbols_data = sd->symbols->data();
symbols_size = sd->symbols_size;
if (sd->symbol_names != NULL)
symbol_names_data = sd->symbol_names->data();
symbol_names_size = sd->symbol_names_size;
}
// Get the section headers.
const unsigned char* shdrs = section_headers_data;
const unsigned char* pshdrs;
// Get the section names.
const unsigned char* pnamesu = (is_two_pass
? gc_sd->section_names_data
: sd->section_names->data());
const char* pnames = reinterpret_cast<const char*>(pnamesu);
// If any input files have been claimed by plugins, we need to defer
// actual layout until the replacement files have arrived.
const bool should_defer_layout =
(parameters->options().has_plugins()
&& parameters->options().plugins()->should_defer_layout());
unsigned int num_sections_to_defer = 0;
// For each section, record the index of the reloc section if any.
// Use 0 to mean that there is no reloc section, -1U to mean that
// there is more than one.
std::vector<unsigned int> reloc_shndx(shnum, 0);
std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
// Skip the first, dummy, section.
pshdrs = shdrs + This::shdr_size;
for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
{
typename This::Shdr shdr(pshdrs);
// Count the number of sections whose layout will be deferred.
if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
++num_sections_to_defer;
unsigned int sh_type = shdr.get_sh_type();
if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
{
unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
if (target_shndx == 0 || target_shndx >= shnum)
{
this->error(_("relocation section %u has bad info %u"),
i, target_shndx);
continue;
}
if (reloc_shndx[target_shndx] != 0)
reloc_shndx[target_shndx] = -1U;
else
{
reloc_shndx[target_shndx] = i;
reloc_type[target_shndx] = sh_type;
}
}
}
Output_sections& out_sections(this->output_sections());
std::vector<Address>& out_section_offsets(this->section_offsets());
if (!is_pass_two)
{
out_sections.resize(shnum);
out_section_offsets.resize(shnum);
}
// If we are only linking for symbols, then there is nothing else to
// do here.
if (this->input_file()->just_symbols())
{
if (!is_pass_two)
{
delete sd->section_headers;
sd->section_headers = NULL;
delete sd->section_names;
sd->section_names = NULL;
}
return;
}
if (num_sections_to_defer > 0)
{
parameters->options().plugins()->add_deferred_layout_object(this);
this->deferred_layout_.reserve(num_sections_to_defer);
this->is_deferred_layout_ = true;
}
// Whether we've seen a .note.GNU-stack section.
bool seen_gnu_stack = false;
// The flags of a .note.GNU-stack section.
uint64_t gnu_stack_flags = 0;
// Keep track of which sections to omit.
std::vector<bool> omit(shnum, false);
// Keep track of reloc sections when emitting relocations.
const bool relocatable = parameters->options().relocatable();
const bool emit_relocs = (relocatable
|| parameters->options().emit_relocs());
std::vector<unsigned int> reloc_sections;
// Keep track of .eh_frame sections.
std::vector<unsigned int> eh_frame_sections;
// Keep track of .debug_info and .debug_types sections.
std::vector<unsigned int> debug_info_sections;
std::vector<unsigned int> debug_types_sections;
// Skip the first, dummy, section.
pshdrs = shdrs + This::shdr_size;
for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
{
typename This::Shdr shdr(pshdrs);
if (shdr.get_sh_name() >= section_names_size)
{
this->error(_("bad section name offset for section %u: %lu"),
i, static_cast<unsigned long>(shdr.get_sh_name()));
return;
}
const char* name = pnames + shdr.get_sh_name();
if (!is_pass_two)
{
if (this->handle_gnu_warning_section(name, i, symtab))
{
if (!relocatable && !parameters->options().shared())
omit[i] = true;
}
// The .note.GNU-stack section is special. It gives the
// protection flags that this object file requires for the stack
// in memory.
if (strcmp(name, ".note.GNU-stack") == 0)
{
seen_gnu_stack = true;
gnu_stack_flags |= shdr.get_sh_flags();
omit[i] = true;
}
// The .note.GNU-split-stack section is also special. It
// indicates that the object was compiled with
// -fsplit-stack.
if (this->handle_split_stack_section(name))
{
if (!relocatable && !parameters->options().shared())
omit[i] = true;
}
// Skip attributes section.
if (parameters->target().is_attributes_section(name))
{
omit[i] = true;
}
bool discard = omit[i];
if (!discard)
{
if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
{
if (!this->include_section_group(symtab, layout, i, name,
shdrs, pnames,
section_names_size,
&omit))
discard = true;
}
else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
&& Layout::is_linkonce(name))
{
if (!this->include_linkonce_section(layout, i, name, shdr))
discard = true;
}
}
// Add the section to the incremental inputs layout.
Incremental_inputs* incremental_inputs = layout->incremental_inputs();
if (incremental_inputs != NULL
&& !discard
&& can_incremental_update(shdr.get_sh_type()))
{
off_t sh_size = shdr.get_sh_size();
section_size_type uncompressed_size;
if (this->section_is_compressed(i, &uncompressed_size))
sh_size = uncompressed_size;
incremental_inputs->report_input_section(this, i, name, sh_size);
}
if (discard)
{
// Do not include this section in the link.
out_sections[i] = NULL;
out_section_offsets[i] = invalid_address;
continue;
}
}
if (is_pass_one && parameters->options().gc_sections())
{
if (this->is_section_name_included(name)
|| layout->keep_input_section (this, name)
|| shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
|| shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
{
symtab->gc()->worklist().push_back(Section_id(this, i));
}
// If the section name XXX can be represented as a C identifier
// it cannot be discarded if there are references to
// __start_XXX and __stop_XXX symbols. These need to be
// specially handled.
if (is_cident(name))
{
symtab->gc()->add_cident_section(name, Section_id(this, i));
}
}
// When doing a relocatable link we are going to copy input
// reloc sections into the output. We only want to copy the
// ones associated with sections which are not being discarded.
// However, we don't know that yet for all sections. So save
// reloc sections and process them later. Garbage collection is
// not triggered when relocatable code is desired.
if (emit_relocs
&& (shdr.get_sh_type() == elfcpp::SHT_REL
|| shdr.get_sh_type() == elfcpp::SHT_RELA))
{
reloc_sections.push_back(i);
continue;
}
if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
continue;
// The .eh_frame section is special. It holds exception frame
// information that we need to read in order to generate the
// exception frame header. We process these after all the other
// sections so that the exception frame reader can reliably
// determine which sections are being discarded, and discard the
// corresponding information.
if (!relocatable
&& strcmp(name, ".eh_frame") == 0
&& this->check_eh_frame_flags(&shdr))
{
if (is_pass_one)
{
if (this->is_deferred_layout())
out_sections[i] = reinterpret_cast<Output_section*>(2);
else
out_sections[i] = reinterpret_cast<Output_section*>(1);
out_section_offsets[i] = invalid_address;
}
else if (this->is_deferred_layout())
this->deferred_layout_.push_back(Deferred_layout(i, name,
pshdrs,
reloc_shndx[i],
reloc_type[i]));
else
eh_frame_sections.push_back(i);
continue;
}
if (is_pass_two && parameters->options().gc_sections())
{
// This is executed during the second pass of garbage
// collection. do_layout has been called before and some
// sections have been already discarded. Simply ignore
// such sections this time around.
if (out_sections[i] == NULL)
{
gold_assert(out_section_offsets[i] == invalid_address);
continue;
}
if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
&& symtab->gc()->is_section_garbage(this, i))
{
if (parameters->options().print_gc_sections())
gold_info(_("%s: removing unused section from '%s'"
" in file '%s'"),
program_name, this->section_name(i).c_str(),
this->name().c_str());
out_sections[i] = NULL;
out_section_offsets[i] = invalid_address;
continue;
}
}
if (is_pass_two && parameters->options().icf_enabled())
{
if (out_sections[i] == NULL)
{
gold_assert(out_section_offsets[i] == invalid_address);
continue;
}
if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
&& symtab->icf()->is_section_folded(this, i))
{
if (parameters->options().print_icf_sections())
{
Section_id folded =
symtab->icf()->get_folded_section(this, i);
Relobj* folded_obj =
reinterpret_cast<Relobj*>(folded.first);
gold_info(_("%s: ICF folding section '%s' in file '%s' "
"into '%s' in file '%s'"),
program_name, this->section_name(i).c_str(),
this->name().c_str(),
folded_obj->section_name(folded.second).c_str(),
folded_obj->name().c_str());
}
out_sections[i] = NULL;
out_section_offsets[i] = invalid_address;
continue;
}
}
// Defer layout here if input files are claimed by plugins. When gc
// is turned on this function is called twice; we only want to do this
// on the first pass.
if (!is_pass_two
&& this->is_deferred_layout()
&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
{
this->deferred_layout_.push_back(Deferred_layout(i, name,
pshdrs,
reloc_shndx[i],
reloc_type[i]));
// Put dummy values here; real values will be supplied by
// do_layout_deferred_sections.
out_sections[i] = reinterpret_cast<Output_section*>(2);
out_section_offsets[i] = invalid_address;
continue;
}
// During gc_pass_two if a section that was previously deferred is
// found, do not layout the section as layout_deferred_sections will
// do it later from gold.cc.
if (is_pass_two
&& (out_sections[i] == reinterpret_cast<Output_section*>(2)))
continue;
if (is_pass_one)
{
// This is during garbage collection. The out_sections are
// assigned in the second call to this function.
out_sections[i] = reinterpret_cast<Output_section*>(1);
out_section_offsets[i] = invalid_address;
}
else
{
// When garbage collection is switched on the actual layout
// only happens in the second call.
this->layout_section(layout, i, name, shdr, reloc_shndx[i],
reloc_type[i]);
// When generating a .gdb_index section, we do additional
// processing of .debug_info and .debug_types sections after all
// the other sections for the same reason as above.
if (!relocatable
&& parameters->options().gdb_index()
&& !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
{
if (strcmp(name, ".debug_info") == 0
|| strcmp(name, ".zdebug_info") == 0)
debug_info_sections.push_back(i);
else if (strcmp(name, ".debug_types") == 0
|| strcmp(name, ".zdebug_types") == 0)
debug_types_sections.push_back(i);
}
}
}
if (!is_pass_two)
layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
// Handle the .eh_frame sections after the other sections.
gold_assert(!is_pass_one || eh_frame_sections.empty());
for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
p != eh_frame_sections.end();
++p)
{
unsigned int i = *p;
const unsigned char* pshdr;
pshdr = section_headers_data + i * This::shdr_size;
typename This::Shdr shdr(pshdr);
this->layout_eh_frame_section(layout,
symbols_data,
symbols_size,
symbol_names_data,
symbol_names_size,
i,
shdr,
reloc_shndx[i],
reloc_type[i]);
}
// When doing a relocatable link handle the reloc sections at the
// end. Garbage collection and Identical Code Folding is not
// turned on for relocatable code.
if (emit_relocs)
this->size_relocatable_relocs();
gold_assert(!is_two_pass || reloc_sections.empty());
for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
p != reloc_sections.end();
++p)
{
unsigned int i = *p;
const unsigned char* pshdr;
pshdr = section_headers_data + i * This::shdr_size;
typename This::Shdr shdr(pshdr);
unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
if (data_shndx >= shnum)
{
// We already warned about this above.
continue;
}
Output_section* data_section = out_sections[data_shndx];
if (data_section == reinterpret_cast<Output_section*>(2))
{
if (is_pass_two)
continue;
// The layout for the data section was deferred, so we need
// to defer the relocation section, too.
const char* name = pnames + shdr.get_sh_name();
this->deferred_layout_relocs_.push_back(
Deferred_layout(i, name, pshdr, 0, elfcpp::SHT_NULL));
out_sections[i] = reinterpret_cast<Output_section*>(2);
out_section_offsets[i] = invalid_address;
continue;
}
if (data_section == NULL)
{
out_sections[i] = NULL;
out_section_offsets[i] = invalid_address;
continue;
}
Relocatable_relocs* rr = new Relocatable_relocs();
this->set_relocatable_relocs(i, rr);
Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
rr);
out_sections[i] = os;
out_section_offsets[i] = invalid_address;
}
// When building a .gdb_index section, scan the .debug_info and
// .debug_types sections.
gold_assert(!is_pass_one
|| (debug_info_sections.empty() && debug_types_sections.empty()));
for (std::vector<unsigned int>::const_iterator p
= debug_info_sections.begin();
p != debug_info_sections.end();
++p)
{
unsigned int i = *p;
layout->add_to_gdb_index(false, this, symbols_data, symbols_size,
i, reloc_shndx[i], reloc_type[i]);
}
for (std::vector<unsigned int>::const_iterator p
= debug_types_sections.begin();
p != debug_types_sections.end();
++p)
{
unsigned int i = *p;
layout->add_to_gdb_index(true, this, symbols_data, symbols_size,
i, reloc_shndx[i], reloc_type[i]);
}
if (is_pass_two)
{
delete[] gc_sd->section_headers_data;
delete[] gc_sd->section_names_data;
delete[] gc_sd->symbols_data;
delete[] gc_sd->symbol_names_data;
this->set_symbols_data(NULL);
}
else
{
delete sd->section_headers;
sd->section_headers = NULL;
delete sd->section_names;
sd->section_names = NULL;
}
}
// Layout sections whose layout was deferred while waiting for
// input files from a plugin.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
{
typename std::vector<Deferred_layout>::iterator deferred;
for (deferred = this->deferred_layout_.begin();
deferred != this->deferred_layout_.end();
++deferred)
{
typename This::Shdr shdr(deferred->shdr_data_);
if (!parameters->options().relocatable()
&& deferred->name_ == ".eh_frame"
&& this->check_eh_frame_flags(&shdr))
{
// Checking is_section_included is not reliable for
// .eh_frame sections, because they do not have an output
// section. This is not a problem normally because we call
// layout_eh_frame_section unconditionally, but when
// deferring sections that is not true. We don't want to
// keep all .eh_frame sections because that will cause us to
// keep all sections that they refer to, which is the wrong
// way around. Instead, the eh_frame code will discard
// .eh_frame sections that refer to discarded sections.
// Reading the symbols again here may be slow.
Read_symbols_data sd;
this->base_read_symbols(&sd);
this->layout_eh_frame_section(layout,
sd.symbols->data(),
sd.symbols_size,
sd.symbol_names->data(),
sd.symbol_names_size,
deferred->shndx_,
shdr,
deferred->reloc_shndx_,
deferred->reloc_type_);
continue;
}
// If the section is not included, it is because the garbage collector
// decided it is not needed. Avoid reverting that decision.
if (!this->is_section_included(deferred->shndx_))
continue;
this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
shdr, deferred->reloc_shndx_,
deferred->reloc_type_);
}
this->deferred_layout_.clear();
// Now handle the deferred relocation sections.
Output_sections& out_sections(this->output_sections());
std::vector<Address>& out_section_offsets(this->section_offsets());
for (deferred = this->deferred_layout_relocs_.begin();
deferred != this->deferred_layout_relocs_.end();
++deferred)
{
unsigned int shndx = deferred->shndx_;
typename This::Shdr shdr(deferred->shdr_data_);
unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
Output_section* data_section = out_sections[data_shndx];
if (data_section == NULL)
{
out_sections[shndx] = NULL;
out_section_offsets[shndx] = invalid_address;
continue;
}
Relocatable_relocs* rr = new Relocatable_relocs();
this->set_relocatable_relocs(shndx, rr);
Output_section* os = layout->layout_reloc(this, shndx, shdr,
data_section, rr);
out_sections[shndx] = os;
out_section_offsets[shndx] = invalid_address;
}
}
// Add the symbols to the symbol table.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
Read_symbols_data* sd,
Layout*)
{
if (sd->symbols == NULL)
{
gold_assert(sd->symbol_names == NULL);
return;
}
const int sym_size = This::sym_size;
size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
/ sym_size);
if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
{
this->error(_("size of symbols is not multiple of symbol size"));
return;
}
this->symbols_.resize(symcount);
const char* sym_names =
reinterpret_cast<const char*>(sd->symbol_names->data());
symtab->add_from_relobj(this,
sd->symbols->data() + sd->external_symbols_offset,
symcount, this->local_symbol_count_,
sym_names, sd->symbol_names_size,
&this->symbols_,
&this->defined_count_);
delete sd->symbols;
sd->symbols = NULL;
delete sd->symbol_names;
sd->symbol_names = NULL;
}
// Find out if this object, that is a member of a lib group, should be included
// in the link. We check every symbol defined by this object. If the symbol
// table has a strong undefined reference to that symbol, we have to include
// the object.
template<int size, bool big_endian>
Archive::Should_include
Sized_relobj_file<size, big_endian>::do_should_include_member(
Symbol_table* symtab,
Layout* layout,
Read_symbols_data* sd,
std::string* why)
{
char* tmpbuf = NULL;
size_t tmpbuflen = 0;
const char* sym_names =
reinterpret_cast<const char*>(sd->symbol_names->data());
const unsigned char* syms =
sd->symbols->data() + sd->external_symbols_offset;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
/ sym_size);
const unsigned char* p = syms;
for (size_t i = 0; i < symcount; ++i, p += sym_size)
{
elfcpp::Sym<size, big_endian> sym(p);
unsigned int st_shndx = sym.get_st_shndx();
if (st_shndx == elfcpp::SHN_UNDEF)
continue;
unsigned int st_name = sym.get_st_name();
const char* name = sym_names + st_name;
Symbol* symbol;
Archive::Should_include t = Archive::should_include_member(symtab,
layout,
name,
&symbol, why,
&tmpbuf,
&tmpbuflen);
if (t == Archive::SHOULD_INCLUDE_YES)
{
if (tmpbuf != NULL)
free(tmpbuf);
return t;
}
}
if (tmpbuf != NULL)
free(tmpbuf);
return Archive::SHOULD_INCLUDE_UNKNOWN;
}
// Iterate over global defined symbols, calling a visitor class V for each.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
Read_symbols_data* sd,
Library_base::Symbol_visitor_base* v)
{
const char* sym_names =
reinterpret_cast<const char*>(sd->symbol_names->data());
const unsigned char* syms =
sd->symbols->data() + sd->external_symbols_offset;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
/ sym_size);
const unsigned char* p = syms;
for (size_t i = 0; i < symcount; ++i, p += sym_size)
{
elfcpp::Sym<size, big_endian> sym(p);
if (sym.get_st_shndx() != elfcpp::SHN_UNDEF)
v->visit(sym_names + sym.get_st_name());
}
}
// Return whether the local symbol SYMNDX has a PLT offset.
template<int size, bool big_endian>
bool
Sized_relobj_file<size, big_endian>::local_has_plt_offset(
unsigned int symndx) const
{
typename Local_plt_offsets::const_iterator p =
this->local_plt_offsets_.find(symndx);
return p != this->local_plt_offsets_.end();
}
// Get the PLT offset of a local symbol.
template<int size, bool big_endian>
unsigned int
Sized_relobj_file<size, big_endian>::do_local_plt_offset(
unsigned int symndx) const
{
typename Local_plt_offsets::const_iterator p =
this->local_plt_offsets_.find(symndx);
gold_assert(p != this->local_plt_offsets_.end());
return p->second;
}
// Set the PLT offset of a local symbol.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::set_local_plt_offset(
unsigned int symndx, unsigned int plt_offset)
{
std::pair<typename Local_plt_offsets::iterator, bool> ins =
this->local_plt_offsets_.insert(std::make_pair(symndx, plt_offset));
gold_assert(ins.second);
}
// First pass over the local symbols. Here we add their names to
// *POOL and *DYNPOOL, and we store the symbol value in
// THIS->LOCAL_VALUES_. This function is always called from a
// singleton thread. This is followed by a call to
// finalize_local_symbols.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
Stringpool* dynpool)
{
gold_assert(this->symtab_shndx_ != -1U);
if (this->symtab_shndx_ == 0)
{
// This object has no symbols. Weird but legal.
return;
}
// Read the symbol table section header.
const unsigned int symtab_shndx = this->symtab_shndx_;
typename This::Shdr symtabshdr(this,
this->elf_file_.section_header(symtab_shndx));
gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
// Read the local symbols.
const int sym_size = This::sym_size;
const unsigned int loccount = this->local_symbol_count_;
gold_assert(loccount == symtabshdr.get_sh_info());
off_t locsize = loccount * sym_size;
const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
locsize, true, true);
// Read the symbol names.
const unsigned int strtab_shndx =
this->adjust_shndx(symtabshdr.get_sh_link());
section_size_type strtab_size;
const unsigned char* pnamesu = this->section_contents(strtab_shndx,
&strtab_size,
true);
const char* pnames = reinterpret_cast<const char*>(pnamesu);
// Loop over the local symbols.
const Output_sections& out_sections(this->output_sections());
std::vector<Address>& out_section_offsets(this->section_offsets());
unsigned int shnum = this->shnum();
unsigned int count = 0;
unsigned int dyncount = 0;
// Skip the first, dummy, symbol.
psyms += sym_size;
bool strip_all = parameters->options().strip_all();
bool discard_all = parameters->options().discard_all();
bool discard_locals = parameters->options().discard_locals();
bool discard_sec_merge = parameters->options().discard_sec_merge();
for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
{
elfcpp::Sym<size, big_endian> sym(psyms);
Symbol_value<size>& lv(this->local_values_[i]);
bool is_ordinary;
unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
&is_ordinary);
lv.set_input_shndx(shndx, is_ordinary);
if (sym.get_st_type() == elfcpp::STT_SECTION)
lv.set_is_section_symbol();
else if (sym.get_st_type() == elfcpp::STT_TLS)
lv.set_is_tls_symbol();
else if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
lv.set_is_ifunc_symbol();
// Save the input symbol value for use in do_finalize_local_symbols().
lv.set_input_value(sym.get_st_value());
// Decide whether this symbol should go into the output file.
if ((shndx < shnum && out_sections[shndx] == NULL)
|| shndx == this->discarded_eh_frame_shndx_)
{
lv.set_no_output_symtab_entry();
gold_assert(!lv.needs_output_dynsym_entry());
continue;
}
if (sym.get_st_type() == elfcpp::STT_SECTION
|| !this->adjust_local_symbol(&lv))
{
lv.set_no_output_symtab_entry();
gold_assert(!lv.needs_output_dynsym_entry());
continue;
}
if (sym.get_st_name() >= strtab_size)
{
this->error(_("local symbol %u section name out of range: %u >= %u"),
i, sym.get_st_name(),
static_cast<unsigned int>(strtab_size));
lv.set_no_output_symtab_entry();
continue;
}
const char* name = pnames + sym.get_st_name();
// If needed, add the symbol to the dynamic symbol table string pool.
if (lv.needs_output_dynsym_entry())
{
dynpool->add(name, true, NULL);
++dyncount;
}
if (strip_all
|| (discard_all && lv.may_be_discarded_from_output_symtab()))
{
lv.set_no_output_symtab_entry();
continue;
}
// By default, discard temporary local symbols in merge sections.
// If --discard-locals option is used, discard all temporary local
// symbols. These symbols start with system-specific local label
// prefixes, typically .L for ELF system. We want to be compatible
// with GNU ld so here we essentially use the same check in
// bfd_is_local_label(). The code is different because we already
// know that:
//
// - the symbol is local and thus cannot have global or weak binding.
// - the symbol is not a section symbol.
// - the symbol has a name.
//
// We do not discard a symbol if it needs a dynamic symbol entry.
if ((discard_locals
|| (discard_sec_merge
&& is_ordinary
&& out_section_offsets[shndx] == invalid_address))
&& sym.get_st_type() != elfcpp::STT_FILE
&& !lv.needs_output_dynsym_entry()
&& lv.may_be_discarded_from_output_symtab()
&& parameters->target().is_local_label_name(name))
{
lv.set_no_output_symtab_entry();
continue;
}
// Discard the local symbol if -retain_symbols_file is specified
// and the local symbol is not in that file.
if (!parameters->options().should_retain_symbol(name))
{
lv.set_no_output_symtab_entry();
continue;
}
// Add the symbol to the symbol table string pool.
pool->add(name, true, NULL);
++count;
}
this->output_local_symbol_count_ = count;
this->output_local_dynsym_count_ = dyncount;
}
// Compute the final value of a local symbol.
template<int size, bool big_endian>
typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
Sized_relobj_file<size, big_endian>::compute_final_local_value_internal(
unsigned int r_sym,
const Symbol_value<size>* lv_in,
Symbol_value<size>* lv_out,
bool relocatable,
const Output_sections& out_sections,
const std::vector<Address>& out_offsets,
const Symbol_table* symtab)
{
// We are going to overwrite *LV_OUT, if it has a merged symbol value,
// we may have a memory leak.
gold_assert(lv_out->has_output_value());
bool is_ordinary;
unsigned int shndx = lv_in->input_shndx(&is_ordinary);
// Set the output symbol value.
if (!is_ordinary)
{
if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
lv_out->set_output_value(lv_in->input_value());
else
{
this->error(_("unknown section index %u for local symbol %u"),
shndx, r_sym);
lv_out->set_output_value(0);
return This::CFLV_ERROR;
}
}
else
{
if (shndx >= this->shnum())
{
this->error(_("local symbol %u section index %u out of range"),
r_sym, shndx);
lv_out->set_output_value(0);
return This::CFLV_ERROR;
}
Output_section* os = out_sections[shndx];
Address secoffset = out_offsets[shndx];
if (symtab->is_section_folded(this, shndx))
{
gold_assert(os == NULL && secoffset == invalid_address);
// Get the os of the section it is folded onto.
Section_id folded = symtab->icf()->get_folded_section(this,
shndx);
gold_assert(folded.first != NULL);
Sized_relobj_file<size, big_endian>* folded_obj = reinterpret_cast
<Sized_relobj_file<size, big_endian>*>(folded.first);
os = folded_obj->output_section(folded.second);
gold_assert(os != NULL);
secoffset = folded_obj->get_output_section_offset(folded.second);
// This could be a relaxed input section.
if (secoffset == invalid_address)
{
const Output_relaxed_input_section* relaxed_section =
os->find_relaxed_input_section(folded_obj, folded.second);
gold_assert(relaxed_section != NULL);
secoffset = relaxed_section->address() - os->address();
}
}
if (os == NULL)
{
// This local symbol belongs to a section we are discarding.
// In some cases when applying relocations later, we will
// attempt to match it to the corresponding kept section,
// so we leave the input value unchanged here.
return This::CFLV_DISCARDED;
}
else if (secoffset == invalid_address)
{
uint64_t start;
// This is a SHF_MERGE section or one which otherwise
// requires special handling.
if (shndx == this->discarded_eh_frame_shndx_)
{
// This local symbol belongs to a discarded .eh_frame
// section. Just treat it like the case in which
// os == NULL above.
gold_assert(this->has_eh_frame_);
return This::CFLV_DISCARDED;
}
else if (!lv_in->is_section_symbol())
{
// This is not a section symbol. We can determine
// the final value now.
lv_out->set_output_value(
os->output_address(this, shndx, lv_in->input_value()));
}
else if (!os->find_starting_output_address(this, shndx, &start))
{
// This is a section symbol, but apparently not one in a
// merged section. First check to see if this is a relaxed
// input section. If so, use its address. Otherwise just
// use the start of the output section. This happens with
// relocatable links when the input object has section
// symbols for arbitrary non-merge sections.
const Output_section_data* posd =
os->find_relaxed_input_section(this, shndx);
if (posd != NULL)
{
Address relocatable_link_adjustment =
relocatable ? os->address() : 0;
lv_out->set_output_value(posd->address()
- relocatable_link_adjustment);
}
else
lv_out->set_output_value(os->address());
}
else
{
// We have to consider the addend to determine the
// value to use in a relocation. START is the start
// of this input section. If we are doing a relocatable
// link, use offset from start output section instead of
// address.
Address adjusted_start =
relocatable ? start - os->address() : start;
Merged_symbol_value<size>* msv =
new Merged_symbol_value<size>(lv_in->input_value(),
adjusted_start);
lv_out->set_merged_symbol_value(msv);
}
}
else if (lv_in->is_tls_symbol()
|| (lv_in->is_section_symbol()
&& (os->flags() & elfcpp::SHF_TLS)))
lv_out->set_output_value(os->tls_offset()
+ secoffset
+ lv_in->input_value());
else
lv_out->set_output_value((relocatable ? 0 : os->address())
+ secoffset
+ lv_in->input_value());
}
return This::CFLV_OK;
}
// Compute final local symbol value. R_SYM is the index of a local
// symbol in symbol table. LV points to a symbol value, which is
// expected to hold the input value and to be over-written by the
// final value. SYMTAB points to a symbol table. Some targets may want
// to know would-be-finalized local symbol values in relaxation.
// Hence we provide this method. Since this method updates *LV, a
// callee should make a copy of the original local symbol value and
// use the copy instead of modifying an object's local symbols before
// everything is finalized. The caller should also free up any allocated
// memory in the return value in *LV.
template<int size, bool big_endian>
typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
Sized_relobj_file<size, big_endian>::compute_final_local_value(
unsigned int r_sym,
const Symbol_value<size>* lv_in,
Symbol_value<size>* lv_out,
const Symbol_table* symtab)
{
// This is just a wrapper of compute_final_local_value_internal.
const bool relocatable = parameters->options().relocatable();
const Output_sections& out_sections(this->output_sections());
const std::vector<Address>& out_offsets(this->section_offsets());
return this->compute_final_local_value_internal(r_sym, lv_in, lv_out,
relocatable, out_sections,
out_offsets, symtab);
}
// Finalize the local symbols. Here we set the final value in
// THIS->LOCAL_VALUES_ and set their output symbol table indexes.
// This function is always called from a singleton thread. The actual
// output of the local symbols will occur in a separate task.
template<int size, bool big_endian>
unsigned int
Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
unsigned int index,
off_t off,
Symbol_table* symtab)
{
gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
const unsigned int loccount = this->local_symbol_count_;
this->local_symbol_offset_ = off;
const bool relocatable = parameters->options().relocatable();
const Output_sections& out_sections(this->output_sections());
const std::vector<Address>& out_offsets(this->section_offsets());
for (unsigned int i = 1; i < loccount; ++i)
{
Symbol_value<size>* lv = &this->local_values_[i];
Compute_final_local_value_status cflv_status =
this->compute_final_local_value_internal(i, lv, lv, relocatable,
out_sections, out_offsets,
symtab);
switch (cflv_status)
{
case CFLV_OK:
if (!lv->is_output_symtab_index_set())
{
lv->set_output_symtab_index(index);
++index;
}
break;
case CFLV_DISCARDED:
case CFLV_ERROR:
// Do nothing.
break;
default:
gold_unreachable();
}
}
return index;
}
// Set the output dynamic symbol table indexes for the local variables.
template<int size, bool big_endian>
unsigned int
Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
unsigned int index)
{
const unsigned int loccount = this->local_symbol_count_;
for (unsigned int i = 1; i < loccount; ++i)
{
Symbol_value<size>& lv(this->local_values_[i]);
if (lv.needs_output_dynsym_entry())
{
lv.set_output_dynsym_index(index);
++index;
}
}
return index;
}
// Set the offset where local dynamic symbol information will be stored.
// Returns the count of local symbols contributed to the symbol table by
// this object.
template<int size, bool big_endian>
unsigned int
Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
{
gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
this->local_dynsym_offset_ = off;
return this->output_local_dynsym_count_;
}
// If Symbols_data is not NULL get the section flags from here otherwise
// get it from the file.
template<int size, bool big_endian>
uint64_t
Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
{
Symbols_data* sd = this->get_symbols_data();
if (sd != NULL)
{
const unsigned char* pshdrs = sd->section_headers_data
+ This::shdr_size * shndx;
typename This::Shdr shdr(pshdrs);
return shdr.get_sh_flags();
}
// If sd is NULL, read the section header from the file.
return this->elf_file_.section_flags(shndx);
}
// Get the section's ent size from Symbols_data. Called by get_section_contents
// in icf.cc
template<int size, bool big_endian>
uint64_t
Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
{
Symbols_data* sd = this->get_symbols_data();
gold_assert(sd != NULL);
const unsigned char* pshdrs = sd->section_headers_data
+ This::shdr_size * shndx;
typename This::Shdr shdr(pshdrs);
return shdr.get_sh_entsize();
}
// Write out the local symbols.
template<int size, bool big_endian>
void
Sized_relobj_file<size, big_endian>::write_local_symbols(
Output_file* of,
const Stringpool* sympool,
const Stringpool* dynpool,
Output_symtab_xindex* symtab_xindex,
Output_symtab_xindex* dynsym_xindex,
off_t symtab_off)
{
const bool strip_all = parameters->options().strip_all();
if (strip_all)
{
if (this->output_local_dynsym_count_ == 0)
return;
this->output_local_symbol_count_ = 0;
}
gold_assert(this->symtab_shndx_ != -1U);
if (this->symtab_shndx_ == 0)
{
// This object has no symbols. Weird but legal.
return;
}
// Read the symbol table section header.
const unsigned int symtab_shndx = this->symtab_shndx_;
typename This::Shdr symtabshdr(this,
this->elf_file_.section_header(symtab_shndx));
gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
const unsigned int loccount = this->local_symbol_count_;
gold_assert(loccount == symtabshdr.get_sh_info());
// Read the local symbols.
const int sym_size = This::sym_size;
off_t locsize = loccount * sym_size;
const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
locsize, true, false);
// Read the symbol names.
const unsigned int strtab_shndx =
this->adjust_shndx(symtabshdr.get_sh_link());
section_size_type strtab_size;
const unsigned char* pnamesu = this->section_contents(strtab_shndx,
&strtab_size,
false);
const char* pnames = reinterpret_cast<const char*>(pnamesu);
// Get views into the output file for the portions of the symbol table
// and the dynamic symbol table that we will be writing.
off_t output_size = this->output_local_symbol_count_ * sym_size;
unsigned char* oview = NULL;
if (output_size > 0)
oview = of->get_output_view(symtab_off + this->local_symbol_offset_,
output_size);
off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
unsigned char* dyn_oview = NULL;
if (dyn_output_size > 0)
dyn_oview = of->get_output_view(this->local_dynsym_offset_,
dyn_output_size);
const Output_sections& out_sections(this->output_sections());
gold_assert(this->local_values_.size() == loccount);
unsigned char* ov = oview;
unsigned char* dyn_ov = dyn_oview;
psyms += sym_size;
for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
{
elfcpp::Sym<size, big_endian> isym(psyms);
Symbol_value