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binutils-gdb/gold/object.cc
Ian Lance Taylor 8a5e3e08a6 * layout.cc (Layout::make_output_section): Call 
Target::new_output_section.
	(Layout::attach_allocated_section_to_segment): Put large section
	sections in a separate load segment with the large segment flag
	set.
	(Layout::segment_precedes): Sort large data segments after other
	load segments.
	(align_file_offset): New static function.
	(Layout::set_segment_offsets): Use align_file_offset.
	* output.h (class Output_section): Add is_small_section_ and
	is_large_section_ fields.
	(Output_section::is_small_section): New function.
	(Output_section::set_is_small_section):  New function.
	(Output_section::is_large_section): New function.
	(Output_section::set_is_large_section): New function.
	(Output_section::is_large_data_section): New function.
	(class Output_segment): Add is_large_data_segment_ field.
	(Output_segment::is_large_data_segment): New function.
	(Output_segment::set_is_large_data_segment): New function.
	* output.cc (Output_section::Output_section): Initialize new
	fields.
	(Output_segment::Output_segment): Likewise.
	(Output_segment::add_output_section): Add assertion that large
	data sections always go in large data segments.  Force small data
	sections to the end of the list of data sections.  Force small BSS
	sections to the start of the list of BSS sections.  For large BSS
	sections to the end of the list of BSS sections.
	* symtab.h (class Symbol): Declare is_common_shndx.
	(Symbol::is_defined): Check Symbol::is_common_shndx.
	(Symbol::is_common): Likewise.
	(class Symbol_table): Define enum Commons_section_type.  Update
	declarations.  Add small_commons_ and large_commons_ fields.
	* symtab.cc (Symbol::is_common_shndx): New function.
	(Symbol_table::Symbol_table): Initialize new fields.
	(Symbol_table::add_from_object): Put small and large common
	symbols in the right list.
	(Symbol_table::sized_finalized_symbol): Check
	Symbol::is_common_shndx.
	(Symbol_table::sized_write_globals): Likewise.
	* common.cc (Symbol_table::do_allocate_commons): Allocate new
	common symbol lists.  Don't call do_allocate_commons_list if the
	list is empty.
	(Symbol_table::do_allocate_commons_list): Remove is_tls
	parameter.  Add comons_section_type parameter.  Change all
	callers.  Handle small and large common symbols.
	* object.cc (Sized_relobj::do_finalize_local_symbols): Check
	Symbol::is_common_shndx.
	* resolve.cc (symbol_to_bits): Likewise.
	* target.h (Target::small_common_shndx): New function.
	(Target::small_common_section_flags): New function.
	(Target::large_common_shndx): New function.
	(Target::large_common_section_flags): New function.
	(Target::new_output_section): New function.
	(Target::Target_info): Add small_common_shndx, large_common_shndx,
	small_common_section_flags, and large_common_section_flags
	fields.
	(Target::do_new_output_section): New virtual function.
	* arm.cc (Target_arm::arm_info): Initialize new fields.
	* i386.cc (Target_i386::i386_info): Likewise.
	* powerpc.cc (Target_powerpc::powerpc_info) [all versions]:
	Likewise.
	* sparc.c (Target_sparc::sparc_info) [all versions]: Likewise.
	* x86_64.cc (Target_x86_64::x86_64_info): Likewise.
	(Target_x86_64::do_new_output_section): New function.
	* configure.ac: Define conditional MCMODEL_MEDIUM.
	* testsuite/Makefile.am (check_PROGRAMS): Add large.
	(large_SOURCES, large_CFLAGS, large_DEPENDENCIES): Define.
	(large_LDFLAGS): Define.
	* testsuite/large.c: New file.
	* testsuite/testfile.cc (Target_test::test_target_info):
	Initialize new fields.
	* configure, testsuite/Makefile.in: Rebuild.
2009-06-22 06:51:53 +00:00

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// object.cc -- support for an object file for linking in 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 <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"
namespace gold
{
// 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.
// Set the target based on fields in the ELF file header.
void
Object::set_target(int machine, int size, bool big_endian, int osabi,
int abiversion)
{
Target* target = select_target(machine, size, big_endian, osabi, abiversion);
if (target == NULL)
gold_fatal(_("%s: unsupported ELF machine number %d"),
this->name().c_str(), machine);
this->target_ = target;
}
// 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)
{
Location loc(this->do_section_contents(shndx));
*plen = convert_to_section_size_type(loc.data_size);
return this->get_view(loc.file_offset, *plen, true, cache);
}
// Read the section data into SD. This is code common to Sized_relobj
// 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);
std::string warning(reinterpret_cast<const char*>(contents), len);
symtab->add_warning(name + warn_prefix_len, this, warning);
return true;
}
return false;
}
// Class Relobj
// 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(".gnu.linkonce.d", name) &&
strstr(name, "personality")))
{
return true;
}
return false;
}
// Class Sized_relobj.
template<int size, bool big_endian>
Sized_relobj<size, big_endian>::Sized_relobj(
const std::string& name,
Input_file* input_file,
off_t offset,
const elfcpp::Ehdr<size, big_endian>& ehdr)
: Relobj(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_got_offsets_(),
kept_comdat_sections_(),
has_eh_frame_(false),
discarded_eh_frame_shndx_(-1U)
{
}
template<int size, bool big_endian>
Sized_relobj<size, big_endian>::~Sized_relobj()
{
}
// Set up an object file based on the file header. This sets up the
// target and reads the section information.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::setup(
const elfcpp::Ehdr<size, big_endian>& ehdr)
{
this->set_target(ehdr.get_e_machine(), size, big_endian,
ehdr.get_e_ident()[elfcpp::EI_OSABI],
ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
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<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<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<size, big_endian>::check_eh_frame_flags(
const elfcpp::Shdr<size, big_endian>* shdr) const
{
return (shdr->get_sh_type() == elfcpp::SHT_PROGBITS
&& (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
}
// 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<size, big_endian>::find_eh_frame(
const unsigned char* pshdrs,
const char* names,
section_size_type names_size) const
{
const unsigned int shnum = this->shnum();
const unsigned char* p = pshdrs + This::shdr_size;
for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
{
typename This::Shdr shdr(p);
if (this->check_eh_frame_flags(&shdr))
{
if (shdr.get_sh_name() >= names_size)
{
this->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();
if (strcmp(name, ".eh_frame") == 0)
return true;
}
}
return false;
}
// Read the sections and symbols from an object file.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_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);
const unsigned char* namesu = sd->section_names->data();
const char* names = reinterpret_cast<const char*>(namesu);
if (memmem(names, sd->section_names_size, ".eh_frame", 10) != NULL)
{
if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
this->has_eh_frame_ = true;
}
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, 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 = this->has_eh_frame_ ? dataoff : extoff;
section_size_type readsize = this->has_eh_frame_ ? 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 = this->has_eh_frame_ ? 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 cod 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<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<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. This
// is a lot of effort to go to to read a string. Why didn't they
// just have the group signature point into the string table, rather
// than indirect through a symbol?
// 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;
Sized_relobj<size, big_endian>* kept_object = NULL;
Kept_section::Comdat_group* kept_group = NULL;
if ((flags & elfcpp::GRP_COMDAT) == 0)
include_group = true;
else
{
Kept_section this_group(this, index, true);
Kept_section *kept_section_group;
include_group = layout->find_or_add_kept_section(signature,
&this_group,
&kept_section_group);
if (include_group)
kept_section_group->group_sections = new Kept_section::Comdat_group;
kept_group = kept_section_group->group_sections;
kept_object = (static_cast<Sized_relobj<size, big_endian>*>
(kept_section_group->object));
}
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 secnum =
this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
if (relocate_group)
shndxes.push_back(secnum);
if (secnum >= this->shnum())
{
this->error(_("section %u in section group %u out of range"),
secnum, 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 (secnum < index)
this->error(_("invalid section group %u refers to earlier section %u"),
index, secnum);
// Get the name of the member section.
typename This::Shdr member_shdr(shdrs + secnum * 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)
{
(*omit)[secnum] = true;
if (kept_group != NULL)
{
// Find the corresponding kept section, and store that info
// in the discarded section table.
Kept_section::Comdat_group::const_iterator p =
kept_group->find(mname);
if (p != kept_group->end())
{
Kept_comdat_section* kept =
new Kept_comdat_section(kept_object, p->second);
this->set_kept_comdat_section(secnum, kept);
}
}
}
else if (flags & elfcpp::GRP_COMDAT)
{
// Add the section to the kept group table.
gold_assert(kept_group != NULL);
kept_group->insert(std::make_pair(mname, secnum));
}
}
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<size, big_endian>::include_linkonce_section(
Layout* layout,
unsigned int index,
const char* name,
const elfcpp::Shdr<size, big_endian>&)
{
// 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 candidate1(this, index, false);
Kept_section candidate2(this, index, true);
Kept_section* kept1;
Kept_section* kept2;
bool include1 = layout->find_or_add_kept_section(sig1, &candidate1, &kept1);
bool include2 = layout->find_or_add_kept_section(sig2, &candidate2, &kept2);
if (!include2)
{
// The section is being discarded on the basis of its section
// name (i.e., the kept section was also a linkonce section).
// In this case, the section index stored with the layout object
// is the linkonce section that was kept.
unsigned int kept_group_index = kept2->shndx;
Relobj* kept_relobj = kept2->object;
if (kept_relobj != NULL)
{
Sized_relobj<size, big_endian>* kept_object =
static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
Kept_comdat_section* kept =
new Kept_comdat_section(kept_object, kept_group_index);
this->set_kept_comdat_section(index, kept);
}
}
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.
Relobj* kept_relobj = kept1->object;
if (kept_relobj != NULL)
{
Sized_relobj<size, big_endian>* kept_object =
static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
Kept_section::Comdat_group* kept_group = kept1->group_sections;
if (kept_group != NULL && kept_group->size() == 1)
{
Kept_section::Comdat_group::const_iterator p =
kept_group->begin();
gold_assert(p != kept_group->end());
Kept_comdat_section* kept =
new Kept_comdat_section(kept_object, p->second);
this->set_kept_comdat_section(index, kept);
}
}
}
return include1 && include2;
}
// Layout an input section.
template<int size, bool big_endian>
inline void
Sized_relobj<size, big_endian>::layout_section(Layout* layout,
unsigned int shndx,
const char* name,
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();
}
// 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.
// During garbage collection (gc-sections), this function is called
// twice. When it is called the first time, it is for setting up some
// sections as roots to a work-list and to do comdat processing. Actual
// layout happens the second time around after all the relevant sections
// have been determined. The first time, is_worklist_ready is false.
// It is then set to true after the worklist is processed and the relevant
// sections are determined. Then, this function is called again to
// layout the sections.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_layout(Symbol_table* symtab,
Layout* layout,
Read_symbols_data* sd)
{
const unsigned int shnum = this->shnum();
bool is_gc_pass_one = (parameters->options().gc_sections()
&& !symtab->gc()->is_worklist_ready());
bool is_gc_pass_two = (parameters->options().gc_sections()
&& symtab->gc()->is_worklist_ready());
if (shnum == 0)
return;
Symbols_data* gc_sd = NULL;
if (is_gc_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);
}
else if (is_gc_pass_two)
{
gc_sd = this->get_symbols_data();
}
const unsigned char* section_headers_data = NULL;
section_size_type section_names_size;
const unsigned char* symbols_data = NULL;
section_size_type symbols_size;
section_offset_type external_symbols_offset;
const unsigned char* symbol_names_data = NULL;
section_size_type symbol_names_size;
if (parameters->options().gc_sections())
{
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;
external_symbols_offset = gc_sd->external_symbols_offset;
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;
external_symbols_offset = sd->external_symbols_offset;
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 = parameters->options().gc_sections() ?
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_gc_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_gc_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);
}
// 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;
// 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_gc_pass_two)
{
if (this->handle_gnu_warning_section(name, i, symtab))
{
if (!relocatable)
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;
}
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;
}
}
if (discard)
{
// Do not include this section in the link.
out_sections[i] = NULL;
out_section_offsets[i] = invalid_address;
continue;
}
}
if (is_gc_pass_one)
{
if (is_section_name_included(name)
|| shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
|| shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
{
symtab->gc()->worklist().push(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_gc_pass_one)
{
out_sections[i] = reinterpret_cast<Output_section*>(1);
out_section_offsets[i] = invalid_address;
}
else
eh_frame_sections.push_back(i);
continue;
}
if (is_gc_pass_two)
{
// 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)
if (symtab->gc()->referenced_list().find(Section_id(this,i))
== symtab->gc()->referenced_list().end())
{
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;
}
}
// Defer layout here if input files are claimed by plugins. When gc
// is turned on this function is called twice. For the second call
// should_defer_layout should be false.
if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
{
gold_assert(!is_gc_pass_two);
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_gc_pass_two
&& (out_sections[i] == reinterpret_cast<Output_section*>(2)))
continue;
if (is_gc_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]);
}
}
if (!is_gc_pass_one)
layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags);
// When doing a relocatable link handle the reloc sections at the
// end. Garbage collection is not turned on for relocatable code.
if (emit_relocs)
this->size_relocatable_relocs();
gold_assert(!parameters->options().gc_sections() || 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 == 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;
}
// Handle the .eh_frame sections at the end.
gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
p != eh_frame_sections.end();
++p)
{
gold_assert(this->has_eh_frame_);
gold_assert(external_symbols_offset != 0);
unsigned int i = *p;
const unsigned char *pshdr;
pshdr = section_headers_data + i * This::shdr_size;
typename This::Shdr shdr(pshdr);
off_t offset;
Output_section* os = layout->layout_eh_frame(this,
symbols_data,
symbols_size,
symbol_names_data,
symbol_names_size,
i, shdr,
reloc_shndx[i],
reloc_type[i],
&offset);
out_sections[i] = os;
if (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_ = i;
out_section_offsets[i] = invalid_address;
}
else
out_section_offsets[i] = 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[i] != 0)
this->set_relocs_must_follow_section_writes();
}
if (is_gc_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;
}
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<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_);
this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
shdr, deferred->reloc_shndx_, deferred->reloc_type_);
}
this->deferred_layout_.clear();
}
// Add the symbols to the symbol table.
template<int size, bool big_endian>
void
Sized_relobj<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;
}
// 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<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());
unsigned int shnum = this->shnum();
unsigned int count = 0;
unsigned int dyncount = 0;
// Skip the first, dummy, symbol.
psyms += sym_size;
bool discard_locals = parameters->options().discard_locals();
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();
// 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)
{
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;
}
// 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.
const char* name = pnames + sym.get_st_name();
if (discard_locals
&& sym.get_st_type() != elfcpp::STT_FILE
&& !lv.needs_output_dynsym_entry()
&& parameters->target().is_local_label_name(name))
{
lv.set_no_output_symtab_entry();
continue;
}
// Add the symbol to the symbol table string pool.
pool->add(name, true, NULL);
++count;
// If needed, add the symbol to the dynamic symbol table string pool.
if (lv.needs_output_dynsym_entry())
{
dynpool->add(name, true, NULL);
++dyncount;
}
}
this->output_local_symbol_count_ = count;
this->output_local_dynsym_count_ = dyncount;
}
// 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<size, big_endian>::do_finalize_local_symbols(unsigned int index,
off_t off)
{
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_);
unsigned int shnum = this->shnum();
for (unsigned int i = 1; i < loccount; ++i)
{
Symbol_value<size>& lv(this->local_values_[i]);
bool is_ordinary;
unsigned int shndx = lv.input_shndx(&is_ordinary);
// Set the output symbol value.
if (!is_ordinary)
{
if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
lv.set_output_value(lv.input_value());
else
{
this->error(_("unknown section index %u for local symbol %u"),
shndx, i);
lv.set_output_value(0);
}
}
else
{
if (shndx >= shnum)
{
this->error(_("local symbol %u section index %u out of range"),
i, shndx);
shndx = 0;
}
Output_section* os = out_sections[shndx];
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.
continue;
}
else if (out_offsets[shndx] == 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_);
continue;
}
else if (!lv.is_section_symbol())
{
// This is not a section symbol. We can determine
// the final value now.
lv.set_output_value(os->output_address(this, shndx,
lv.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. 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.
lv.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.
Merged_symbol_value<size>* msv =
new Merged_symbol_value<size>(lv.input_value(), start);
lv.set_merged_symbol_value(msv);
}
}
else if (lv.is_tls_symbol())
lv.set_output_value(os->tls_offset()
+ out_offsets[shndx]
+ lv.input_value());
else
lv.set_output_value((relocatable ? 0 : os->address())
+ out_offsets[shndx]
+ lv.input_value());
}
if (lv.needs_output_symtab_entry())
{
lv.set_output_symtab_index(index);
++index;
}
}
return index;
}
// Set the output dynamic symbol table indexes for the local variables.
template<int size, bool big_endian>
unsigned int
Sized_relobj<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<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_;
}
// Write out the local symbols.
template<int size, bool big_endian>
void
Sized_relobj<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)
{
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(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<size>& lv(this->local_values_[i]);
bool is_ordinary;
unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
&is_ordinary);
if (is_ordinary)
{
gold_assert(st_shndx < out_sections.size());
if (out_sections[st_shndx] == NULL)
continue;
st_shndx = out_sections[st_shndx]->out_shndx();
if (st_shndx >= elfcpp::SHN_LORESERVE)
{
if (lv.needs_output_symtab_entry() && !strip_all)
symtab_xindex->add(lv.output_symtab_index(), st_shndx);
if (lv.needs_output_dynsym_entry())
dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
st_shndx = elfcpp::SHN_XINDEX;
}
}
// Write the symbol to the output symbol table.
if (!strip_all && lv.needs_output_symtab_entry())
{
elfcpp::Sym_write<size, big_endian> osym(ov);
gold_assert(isym.get_st_name() < strtab_size);
const char* name = pnames + isym.get_st_name();
osym.put_st_name(sympool->get_offset(name));
osym.put_st_value(this->local_values_[i].value(this, 0));
osym.put_st_size(isym.get_st_size());
osym.put_st_info(isym.get_st_info());
osym.put_st_other(isym.get_st_other());
osym.put_st_shndx(st_shndx);
ov += sym_size;
}
// Write the symbol to the output dynamic symbol table.
if (lv.needs_output_dynsym_entry())
{
gold_assert(dyn_ov < dyn_oview + dyn_output_size);
elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
gold_assert(isym.get_st_name() < strtab_size);
const char* name = pnames + isym.get_st_name();
osym.put_st_name(dynpool->get_offset(name));
osym.put_st_value(this->local_values_[i].value(this, 0));
osym.put_st_size(isym.get_st_size());
osym.put_st_info(isym.get_st_info());
osym.put_st_other(isym.get_st_other());
osym.put_st_shndx(st_shndx);
dyn_ov += sym_size;
}
}
if (output_size > 0)
{
gold_assert(ov - oview == output_size);
of->write_output_view(this->local_symbol_offset_, output_size, oview);
}
if (dyn_output_size > 0)
{
gold_assert(dyn_ov - dyn_oview == dyn_output_size);
of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
dyn_oview);
}
}
// Set *INFO to symbolic information about the offset OFFSET in the
// section SHNDX. Return true if we found something, false if we
// found nothing.
template<int size, bool big_endian>
bool
Sized_relobj<size, big_endian>::get_symbol_location_info(
unsigned int shndx,
off_t offset,
Symbol_location_info* info)
{
if (this->symtab_shndx_ == 0)
return false;
section_size_type symbols_size;
const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
&symbols_size,
false);
unsigned int symbol_names_shndx =
this->adjust_shndx(this->section_link(this->symtab_shndx_));
section_size_type names_size;
const unsigned char* symbol_names_u =
this->section_contents(symbol_names_shndx, &names_size, false);
const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
const int sym_size = This::sym_size;
const size_t count = symbols_size / sym_size;
const unsigned char* p = symbols;
for (size_t i = 0; i < count; ++i, p += sym_size)
{
elfcpp::Sym<size, big_endian> sym(p);
if (sym.get_st_type() == elfcpp::STT_FILE)
{
if (sym.get_st_name() >= names_size)
info->source_file = "(invalid)";
else
info->source_file = symbol_names + sym.get_st_name();
continue;
}
bool is_ordinary;
unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
&is_ordinary);
if (is_ordinary
&& st_shndx == shndx
&& static_cast<off_t>(sym.get_st_value()) <= offset
&& (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
> offset))
{
if (sym.get_st_name() > names_size)
info->enclosing_symbol_name = "(invalid)";
else
{
info->enclosing_symbol_name = symbol_names + sym.get_st_name();
if (parameters->options().do_demangle())
{
char* demangled_name = cplus_demangle(
info->enclosing_symbol_name.c_str(),
DMGL_ANSI | DMGL_PARAMS);
if (demangled_name != NULL)
{
info->enclosing_symbol_name.assign(demangled_name);
free(demangled_name);
}
}
}
return true;
}
}
return false;
}
// Look for a kept section corresponding to the given discarded section,
// and return its output address. This is used only for relocations in
// debugging sections. If we can't find the kept section, return 0.
template<int size, bool big_endian>
typename Sized_relobj<size, big_endian>::Address
Sized_relobj<size, big_endian>::map_to_kept_section(
unsigned int shndx,
bool* found) const
{
Kept_comdat_section *kept = this->get_kept_comdat_section(shndx);
if (kept != NULL)
{
gold_assert(kept->object_ != NULL);
*found = true;
Output_section* os = kept->object_->output_section(kept->shndx_);
Address offset = kept->object_->get_output_section_offset(kept->shndx_);
if (os != NULL && offset != invalid_address)
return os->address() + offset;
}
*found = false;
return 0;
}
// Get symbol counts.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_get_global_symbol_counts(
const Symbol_table*,
size_t* defined,
size_t* used) const
{
*defined = this->defined_count_;
size_t count = 0;
for (Symbols::const_iterator p = this->symbols_.begin();
p != this->symbols_.end();
++p)
if (*p != NULL
&& (*p)->source() == Symbol::FROM_OBJECT
&& (*p)->object() == this
&& (*p)->is_defined())
++count;
*used = count;
}
// Input_objects methods.
// Add a regular relocatable object to the list. Return false if this
// object should be ignored.
bool
Input_objects::add_object(Object* obj)
{
// Set the global target from the first object file we recognize.
Target* target = obj->target();
if (!parameters->target_valid())
set_parameters_target(target);
else if (target != &parameters->target())
{
obj->error(_("incompatible target"));
return false;
}
// Print the filename if the -t/--trace option is selected.
if (parameters->options().trace())
gold_info("%s", obj->name().c_str());
if (!obj->is_dynamic())
this->relobj_list_.push_back(static_cast<Relobj*>(obj));
else
{
// See if this is a duplicate SONAME.
Dynobj* dynobj = static_cast<Dynobj*>(obj);
const char* soname = dynobj->soname();
std::pair<Unordered_set<std::string>::iterator, bool> ins =
this->sonames_.insert(soname);
if (!ins.second)
{
// We have already seen a dynamic object with this soname.
return false;
}
this->dynobj_list_.push_back(dynobj);
}
// Add this object to the cross-referencer if requested.
if (parameters->options().user_set_print_symbol_counts())
{
if (this->cref_ == NULL)
this->cref_ = new Cref();
this->cref_->add_object(obj);
}
return true;
}
// For each dynamic object, record whether we've seen all of its
// explicit dependencies.
void
Input_objects::check_dynamic_dependencies() const
{
for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
p != this->dynobj_list_.end();
++p)
{
const Dynobj::Needed& needed((*p)->needed());
bool found_all = true;
for (Dynobj::Needed::const_iterator pneeded = needed.begin();
pneeded != needed.end();
++pneeded)
{
if (this->sonames_.find(*pneeded) == this->sonames_.end())
{
found_all = false;
break;
}
}
(*p)->set_has_unknown_needed_entries(!found_all);
}
}
// Start processing an archive.
void
Input_objects::archive_start(Archive* archive)
{
if (parameters->options().user_set_print_symbol_counts())
{
if (this->cref_ == NULL)
this->cref_ = new Cref();
this->cref_->add_archive_start(archive);
}
}
// Stop processing an archive.
void
Input_objects::archive_stop(Archive* archive)
{
if (parameters->options().user_set_print_symbol_counts())
this->cref_->add_archive_stop(archive);
}
// Print symbol counts
void
Input_objects::print_symbol_counts(const Symbol_table* symtab) const
{
if (parameters->options().user_set_print_symbol_counts()
&& this->cref_ != NULL)
this->cref_->print_symbol_counts(symtab);
}
// Relocate_info methods.
// Return a string describing the location of a relocation. This is
// only used in error messages.
template<int size, bool big_endian>
std::string
Relocate_info<size, big_endian>::location(size_t, off_t offset) const
{
// See if we can get line-number information from debugging sections.
std::string filename;
std::string file_and_lineno; // Better than filename-only, if available.
Sized_dwarf_line_info<size, big_endian> line_info(this->object);
// This will be "" if we failed to parse the debug info for any reason.
file_and_lineno = line_info.addr2line(this->data_shndx, offset);
std::string ret(this->object->name());
ret += ':';
Symbol_location_info info;
if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
{
ret += " in function ";
ret += info.enclosing_symbol_name;
ret += ":";
filename = info.source_file;
}
if (!file_and_lineno.empty())
ret += file_and_lineno;
else
{
if (!filename.empty())
ret += filename;
ret += "(";
ret += this->object->section_name(this->data_shndx);
char buf[100];
// Offsets into sections have to be positive.
snprintf(buf, sizeof(buf), "+0x%lx", static_cast<long>(offset));
ret += buf;
ret += ")";
}
return ret;
}
} // End namespace gold.
namespace
{
using namespace gold;
// Read an ELF file with the header and return the appropriate
// instance of Object.
template<int size, bool big_endian>
Object*
make_elf_sized_object(const std::string& name, Input_file* input_file,
off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
{
int et = ehdr.get_e_type();
if (et == elfcpp::ET_REL)
{
Sized_relobj<size, big_endian>* obj =
new Sized_relobj<size, big_endian>(name, input_file, offset, ehdr);
obj->setup(ehdr);
return obj;
}
else if (et == elfcpp::ET_DYN)
{
Sized_dynobj<size, big_endian>* obj =
new Sized_dynobj<size, big_endian>(name, input_file, offset, ehdr);
obj->setup(ehdr);
return obj;
}
else
{
gold_error(_("%s: unsupported ELF file type %d"),
name.c_str(), et);
return NULL;
}
}
} // End anonymous namespace.
namespace gold
{
// Return whether INPUT_FILE is an ELF object.
bool
is_elf_object(Input_file* input_file, off_t offset,
const unsigned char** start, int *read_size)
{
off_t filesize = input_file->file().filesize();
int want = elfcpp::Elf_sizes<64>::ehdr_size;
if (filesize - offset < want)
want = filesize - offset;
const unsigned char* p = input_file->file().get_view(offset, 0, want,
true, false);
*start = p;
*read_size = want;
if (want < 4)
return false;
static unsigned char elfmagic[4] =
{
elfcpp::ELFMAG0, elfcpp::ELFMAG1,
elfcpp::ELFMAG2, elfcpp::ELFMAG3
};
return memcmp(p, elfmagic, 4) == 0;
}
// Read an ELF file and return the appropriate instance of Object.
Object*
make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
const unsigned char* p, section_offset_type bytes,
bool* punconfigured)
{
if (punconfigured != NULL)
*punconfigured = false;
if (bytes < elfcpp::EI_NIDENT)
{
gold_error(_("%s: ELF file too short"), name.c_str());
return NULL;
}
int v = p[elfcpp::EI_VERSION];
if (v != elfcpp::EV_CURRENT)
{
if (v == elfcpp::EV_NONE)
gold_error(_("%s: invalid ELF version 0"), name.c_str());
else
gold_error(_("%s: unsupported ELF version %d"), name.c_str(), v);
return NULL;
}
int c = p[elfcpp::EI_CLASS];
if (c == elfcpp::ELFCLASSNONE)
{
gold_error(_("%s: invalid ELF class 0"), name.c_str());
return NULL;
}
else if (c != elfcpp::ELFCLASS32
&& c != elfcpp::ELFCLASS64)
{
gold_error(_("%s: unsupported ELF class %d"), name.c_str(), c);
return NULL;
}
int d = p[elfcpp::EI_DATA];
if (d == elfcpp::ELFDATANONE)
{
gold_error(_("%s: invalid ELF data encoding"), name.c_str());
return NULL;
}
else if (d != elfcpp::ELFDATA2LSB
&& d != elfcpp::ELFDATA2MSB)
{
gold_error(_("%s: unsupported ELF data encoding %d"), name.c_str(), d);
return NULL;
}
bool big_endian = d == elfcpp::ELFDATA2MSB;
if (c == elfcpp::ELFCLASS32)
{
if (bytes < elfcpp::Elf_sizes<32>::ehdr_size)
{
gold_error(_("%s: ELF file too short"), name.c_str());
return NULL;
}
if (big_endian)
{
#ifdef HAVE_TARGET_32_BIG
elfcpp::Ehdr<32, true> ehdr(p);
return make_elf_sized_object<32, true>(name, input_file,
offset, ehdr);
#else
if (punconfigured != NULL)
*punconfigured = true;
else
gold_error(_("%s: not configured to support "
"32-bit big-endian object"),
name.c_str());
return NULL;
#endif
}
else
{
#ifdef HAVE_TARGET_32_LITTLE
elfcpp::Ehdr<32, false> ehdr(p);
return make_elf_sized_object<32, false>(name, input_file,
offset, ehdr);
#else
if (punconfigured != NULL)
*punconfigured = true;
else
gold_error(_("%s: not configured to support "
"32-bit little-endian object"),
name.c_str());
return NULL;
#endif
}
}
else
{
if (bytes < elfcpp::Elf_sizes<64>::ehdr_size)
{
gold_error(_("%s: ELF file too short"), name.c_str());
return NULL;
}
if (big_endian)
{
#ifdef HAVE_TARGET_64_BIG
elfcpp::Ehdr<64, true> ehdr(p);
return make_elf_sized_object<64, true>(name, input_file,
offset, ehdr);
#else
if (punconfigured != NULL)
*punconfigured = true;
else
gold_error(_("%s: not configured to support "
"64-bit big-endian object"),
name.c_str());
return NULL;
#endif
}
else
{
#ifdef HAVE_TARGET_64_LITTLE
elfcpp::Ehdr<64, false> ehdr(p);
return make_elf_sized_object<64, false>(name, input_file,
offset, ehdr);
#else
if (punconfigured != NULL)
*punconfigured = true;
else
gold_error(_("%s: not configured to support "
"64-bit little-endian object"),
name.c_str());
return NULL;
#endif
}
}
}
// Instantiate the templates we need.
#ifdef HAVE_TARGET_32_LITTLE
template
void
Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
Read_symbols_data*);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
Read_symbols_data*);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
Read_symbols_data*);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
Read_symbols_data*);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Sized_relobj<32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Sized_relobj<32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Sized_relobj<64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Sized_relobj<64, true>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
struct Relocate_info<32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
struct Relocate_info<32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
struct Relocate_info<64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
struct Relocate_info<64, true>;
#endif
} // End namespace gold.
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