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binutils-gdb/gold/x86_64.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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// x86_64.cc -- x86_64 target support for gold.
// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.
#include "gold.h"
#include <cstring>
#include "elfcpp.h"
#include "parameters.h"
#include "reloc.h"
#include "x86_64.h"
#include "object.h"
#include "symtab.h"
#include "layout.h"
#include "output.h"
#include "copy-relocs.h"
#include "target.h"
#include "target-reloc.h"
#include "target-select.h"
#include "tls.h"
#include "freebsd.h"
namespace
{
using namespace gold;
class Output_data_plt_x86_64;
// The x86_64 target class.
// See the ABI at
// http://www.x86-64.org/documentation/abi.pdf
// TLS info comes from
// http://people.redhat.com/drepper/tls.pdf
// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
class Target_x86_64 : public Target_freebsd<64, false>
{
public:
// In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
// uses only Elf64_Rela relocation entries with explicit addends."
typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
Target_x86_64()
: Target_freebsd<64, false>(&x86_64_info),
got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
{ }
// Hook for a new output section.
void
do_new_output_section(Output_section*) const;
// Scan the relocations to look for symbol adjustments.
void
gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_symbols);
// Scan the relocations to look for symbol adjustments.
void
scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_symbols);
// Finalize the sections.
void
do_finalize_sections(Layout*);
// Return the value to use for a dynamic which requires special
// treatment.
uint64_t
do_dynsym_value(const Symbol*) const;
// Relocate a section.
void
relocate_section(const Relocate_info<64, false>*,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr view_address,
section_size_type view_size);
// Scan the relocs during a relocatable link.
void
scan_relocatable_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_symbols,
Relocatable_relocs*);
// Relocate a section during a relocatable link.
void
relocate_for_relocatable(const Relocate_info<64, false>*,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
off_t offset_in_output_section,
const Relocatable_relocs*,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr view_address,
section_size_type view_size,
unsigned char* reloc_view,
section_size_type reloc_view_size);
// Return a string used to fill a code section with nops.
std::string
do_code_fill(section_size_type length) const;
// Return whether SYM is defined by the ABI.
bool
do_is_defined_by_abi(const Symbol* sym) const
{ return strcmp(sym->name(), "__tls_get_addr") == 0; }
// Return the size of the GOT section.
section_size_type
got_size()
{
gold_assert(this->got_ != NULL);
return this->got_->data_size();
}
private:
// The class which scans relocations.
class Scan
{
public:
Scan()
: issued_non_pic_error_(false)
{ }
inline void
local(const General_options& options, Symbol_table* symtab,
Layout* layout, Target_x86_64* target,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
const elfcpp::Sym<64, false>& lsym);
inline void
global(const General_options& options, Symbol_table* symtab,
Layout* layout, Target_x86_64* target,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
Symbol* gsym);
private:
static void
unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
static void
unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
Symbol*);
void
check_non_pic(Relobj*, unsigned int r_type);
// Whether we have issued an error about a non-PIC compilation.
bool issued_non_pic_error_;
};
// The class which implements relocation.
class Relocate
{
public:
Relocate()
: skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
{ }
~Relocate()
{
if (this->skip_call_tls_get_addr_)
{
// FIXME: This needs to specify the location somehow.
gold_error(_("missing expected TLS relocation"));
}
}
// Do a relocation. Return false if the caller should not issue
// any warnings about this relocation.
inline bool
relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
size_t relnum, const elfcpp::Rela<64, false>&,
unsigned int r_type, const Sized_symbol<64>*,
const Symbol_value<64>*,
unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
section_size_type);
private:
// Do a TLS relocation.
inline void
relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
size_t relnum, const elfcpp::Rela<64, false>&,
unsigned int r_type, const Sized_symbol<64>*,
const Symbol_value<64>*,
unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
section_size_type);
// Do a TLS General-Dynamic to Initial-Exec transition.
inline void
tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>&, unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr,
section_size_type view_size);
// Do a TLS General-Dynamic to Local-Exec transition.
inline void
tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>&, unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size);
// Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
inline void
tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>&, unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr,
section_size_type view_size);
// Do a TLSDESC-style General-Dynamic to Local-Exec transition.
inline void
tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>&, unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size);
// Do a TLS Local-Dynamic to Local-Exec transition.
inline void
tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>&, unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size);
// Do a TLS Initial-Exec to Local-Exec transition.
static inline void
tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>&, unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size);
// This is set if we should skip the next reloc, which should be a
// PLT32 reloc against ___tls_get_addr.
bool skip_call_tls_get_addr_;
// This is set if we see a relocation which could load the address
// of the TLS block. Whether we see such a relocation determines
// how we handle the R_X86_64_DTPOFF32 relocation, which is used
// in debugging sections.
bool saw_tls_block_reloc_;
};
// A class which returns the size required for a relocation type,
// used while scanning relocs during a relocatable link.
class Relocatable_size_for_reloc
{
public:
unsigned int
get_size_for_reloc(unsigned int, Relobj*);
};
// Adjust TLS relocation type based on the options and whether this
// is a local symbol.
static tls::Tls_optimization
optimize_tls_reloc(bool is_final, int r_type);
// Get the GOT section, creating it if necessary.
Output_data_got<64, false>*
got_section(Symbol_table*, Layout*);
// Get the GOT PLT section.
Output_data_space*
got_plt_section() const
{
gold_assert(this->got_plt_ != NULL);
return this->got_plt_;
}
// Create the PLT section.
void
make_plt_section(Symbol_table* symtab, Layout* layout);
// Create a PLT entry for a global symbol.
void
make_plt_entry(Symbol_table*, Layout*, Symbol*);
// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
void
define_tls_base_symbol(Symbol_table*, Layout*);
// Create the reserved PLT and GOT entries for the TLS descriptor resolver.
void
reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
// Create a GOT entry for the TLS module index.
unsigned int
got_mod_index_entry(Symbol_table* symtab, Layout* layout,
Sized_relobj<64, false>* object);
// Get the PLT section.
Output_data_plt_x86_64*
plt_section() const
{
gold_assert(this->plt_ != NULL);
return this->plt_;
}
// Get the dynamic reloc section, creating it if necessary.
Reloc_section*
rela_dyn_section(Layout*);
// Return true if the symbol may need a COPY relocation.
// References from an executable object to non-function symbols
// defined in a dynamic object may need a COPY relocation.
bool
may_need_copy_reloc(Symbol* gsym)
{
return (!parameters->options().shared()
&& gsym->is_from_dynobj()
&& gsym->type() != elfcpp::STT_FUNC);
}
// Add a potential copy relocation.
void
copy_reloc(Symbol_table* symtab, Layout* layout,
Sized_relobj<64, false>* object,
unsigned int shndx, Output_section* output_section,
Symbol* sym, const elfcpp::Rela<64, false>& reloc)
{
this->copy_relocs_.copy_reloc(symtab, layout,
symtab->get_sized_symbol<64>(sym),
object, shndx, output_section,
reloc, this->rela_dyn_section(layout));
}
// Information about this specific target which we pass to the
// general Target structure.
static const Target::Target_info x86_64_info;
enum Got_type
{
GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset
GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair
GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair
};
// The GOT section.
Output_data_got<64, false>* got_;
// The PLT section.
Output_data_plt_x86_64* plt_;
// The GOT PLT section.
Output_data_space* got_plt_;
// The dynamic reloc section.
Reloc_section* rela_dyn_;
// Relocs saved to avoid a COPY reloc.
Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
// Space for variables copied with a COPY reloc.
Output_data_space* dynbss_;
// Offset of the GOT entry for the TLS module index.
unsigned int got_mod_index_offset_;
// True if the _TLS_MODULE_BASE_ symbol has been defined.
bool tls_base_symbol_defined_;
};
const Target::Target_info Target_x86_64::x86_64_info =
{
64, // size
false, // is_big_endian
elfcpp::EM_X86_64, // machine_code
false, // has_make_symbol
false, // has_resolve
true, // has_code_fill
true, // is_default_stack_executable
'\0', // wrap_char
"/lib/ld64.so.1", // program interpreter
0x400000, // default_text_segment_address
0x1000, // abi_pagesize (overridable by -z max-page-size)
0x1000, // common_pagesize (overridable by -z common-page-size)
elfcpp::SHN_UNDEF, // small_common_shndx
elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
0, // small_common_section_flags
elfcpp::SHF_X86_64_LARGE // large_common_section_flags
};
// This is called when a new output section is created. This is where
// we handle the SHF_X86_64_LARGE.
void
Target_x86_64::do_new_output_section(Output_section *os) const
{
if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
os->set_is_large_section();
}
// Get the GOT section, creating it if necessary.
Output_data_got<64, false>*
Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
{
if (this->got_ == NULL)
{
gold_assert(symtab != NULL && layout != NULL);
this->got_ = new Output_data_got<64, false>();
Output_section* os;
os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
this->got_);
os->set_is_relro();
// The old GNU linker creates a .got.plt section. We just
// create another set of data in the .got section. Note that we
// always create a PLT if we create a GOT, although the PLT
// might be empty.
this->got_plt_ = new Output_data_space(8, "** GOT PLT");
os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
this->got_plt_);
os->set_is_relro();
// The first three entries are reserved.
this->got_plt_->set_current_data_size(3 * 8);
// Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
this->got_plt_,
0, 0, elfcpp::STT_OBJECT,
elfcpp::STB_LOCAL,
elfcpp::STV_HIDDEN, 0,
false, false);
}
return this->got_;
}
// Get the dynamic reloc section, creating it if necessary.
Target_x86_64::Reloc_section*
Target_x86_64::rela_dyn_section(Layout* layout)
{
if (this->rela_dyn_ == NULL)
{
gold_assert(layout != NULL);
this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->rela_dyn_);
}
return this->rela_dyn_;
}
// A class to handle the PLT data.
class Output_data_plt_x86_64 : public Output_section_data
{
public:
typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*,
Output_data_space*);
// Add an entry to the PLT.
void
add_entry(Symbol* gsym);
// Add the reserved TLSDESC_PLT entry to the PLT.
void
reserve_tlsdesc_entry(unsigned int got_offset)
{ this->tlsdesc_got_offset_ = got_offset; }
// Return true if a TLSDESC_PLT entry has been reserved.
bool
has_tlsdesc_entry() const
{ return this->tlsdesc_got_offset_ != -1U; }
// Return the GOT offset for the reserved TLSDESC_PLT entry.
unsigned int
get_tlsdesc_got_offset() const
{ return this->tlsdesc_got_offset_; }
// Return the offset of the reserved TLSDESC_PLT entry.
unsigned int
get_tlsdesc_plt_offset() const
{ return (this->count_ + 1) * plt_entry_size; }
// Return the .rel.plt section data.
const Reloc_section*
rel_plt() const
{ return this->rel_; }
protected:
void
do_adjust_output_section(Output_section* os);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** PLT")); }
private:
// The size of an entry in the PLT.
static const int plt_entry_size = 16;
// The first entry in the PLT.
// From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
// procedure linkage table for both programs and shared objects."
static unsigned char first_plt_entry[plt_entry_size];
// Other entries in the PLT for an executable.
static unsigned char plt_entry[plt_entry_size];
// The reserved TLSDESC entry in the PLT for an executable.
static unsigned char tlsdesc_plt_entry[plt_entry_size];
// Set the final size.
void
set_final_data_size();
// Write out the PLT data.
void
do_write(Output_file*);
// The reloc section.
Reloc_section* rel_;
// The .got section.
Output_data_got<64, false>* got_;
// The .got.plt section.
Output_data_space* got_plt_;
// The number of PLT entries.
unsigned int count_;
// Offset of the reserved TLSDESC_GOT entry when needed.
unsigned int tlsdesc_got_offset_;
};
// Create the PLT section. The ordinary .got section is an argument,
// since we need to refer to the start. We also create our own .got
// section just for PLT entries.
Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
Output_data_got<64, false>* got,
Output_data_space* got_plt)
: Output_section_data(8), got_(got), got_plt_(got_plt), count_(0),
tlsdesc_got_offset_(-1U)
{
this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->rel_);
}
void
Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
{
os->set_entsize(plt_entry_size);
}
// Add an entry to the PLT.
void
Output_data_plt_x86_64::add_entry(Symbol* gsym)
{
gold_assert(!gsym->has_plt_offset());
// Note that when setting the PLT offset we skip the initial
// reserved PLT entry.
gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
++this->count_;
section_offset_type got_offset = this->got_plt_->current_data_size();
// Every PLT entry needs a GOT entry which points back to the PLT
// entry (this will be changed by the dynamic linker, normally
// lazily when the function is called).
this->got_plt_->set_current_data_size(got_offset + 8);
// Every PLT entry needs a reloc.
gsym->set_needs_dynsym_entry();
this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
got_offset, 0);
// Note that we don't need to save the symbol. The contents of the
// PLT are independent of which symbols are used. The symbols only
// appear in the relocations.
}
// Set the final size.
void
Output_data_plt_x86_64::set_final_data_size()
{
unsigned int count = this->count_;
if (this->has_tlsdesc_entry())
++count;
this->set_data_size((count + 1) * plt_entry_size);
}
// The first entry in the PLT for an executable.
unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
{
// From AMD64 ABI Draft 0.98, page 76
0xff, 0x35, // pushq contents of memory address
0, 0, 0, 0, // replaced with address of .got + 8
0xff, 0x25, // jmp indirect
0, 0, 0, 0, // replaced with address of .got + 16
0x90, 0x90, 0x90, 0x90 // noop (x4)
};
// Subsequent entries in the PLT for an executable.
unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
{
// From AMD64 ABI Draft 0.98, page 76
0xff, 0x25, // jmpq indirect
0, 0, 0, 0, // replaced with address of symbol in .got
0x68, // pushq immediate
0, 0, 0, 0, // replaced with offset into relocation table
0xe9, // jmpq relative
0, 0, 0, 0 // replaced with offset to start of .plt
};
// The reserved TLSDESC entry in the PLT for an executable.
unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
{
// From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
// and AMD64/EM64T", Version 0.9.4 (2005-10-10).
0xff, 0x35, // pushq x(%rip)
0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
0xff, 0x25, // jmpq *y(%rip)
0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
0x0f, 0x1f, // nop
0x40, 0
};
// Write out the PLT. This uses the hand-coded instructions above,
// and adjusts them as needed. This is specified by the AMD64 ABI.
void
Output_data_plt_x86_64::do_write(Output_file* of)
{
const off_t offset = this->offset();
const section_size_type oview_size =
convert_to_section_size_type(this->data_size());
unsigned char* const oview = of->get_output_view(offset, oview_size);
const off_t got_file_offset = this->got_plt_->offset();
const section_size_type got_size =
convert_to_section_size_type(this->got_plt_->data_size());
unsigned char* const got_view = of->get_output_view(got_file_offset,
got_size);
unsigned char* pov = oview;
// The base address of the .plt section.
elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
// The base address of the .got section.
elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
// The base address of the PLT portion of the .got section,
// which is where the GOT pointer will point, and where the
// three reserved GOT entries are located.
elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
memcpy(pov, first_plt_entry, plt_entry_size);
// We do a jmp relative to the PC at the end of this instruction.
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
(got_address + 8
- (plt_address + 6)));
elfcpp::Swap<32, false>::writeval(pov + 8,
(got_address + 16
- (plt_address + 12)));
pov += plt_entry_size;
unsigned char* got_pov = got_view;
memset(got_pov, 0, 24);
got_pov += 24;
unsigned int plt_offset = plt_entry_size;
unsigned int got_offset = 24;
const unsigned int count = this->count_;
for (unsigned int plt_index = 0;
plt_index < count;
++plt_index,
pov += plt_entry_size,
got_pov += 8,
plt_offset += plt_entry_size,
got_offset += 8)
{
// Set and adjust the PLT entry itself.
memcpy(pov, plt_entry, plt_entry_size);
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
(got_address + got_offset
- (plt_address + plt_offset
+ 6)));
elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
elfcpp::Swap<32, false>::writeval(pov + 12,
- (plt_offset + plt_entry_size));
// Set the entry in the GOT.
elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
}
if (this->has_tlsdesc_entry())
{
// Set and adjust the reserved TLSDESC PLT entry.
unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
(got_address + 8
- (plt_address + plt_offset
+ 6)));
elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
(got_base
+ tlsdesc_got_offset
- (plt_address + plt_offset
+ 12)));
pov += plt_entry_size;
}
gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
of->write_output_view(offset, oview_size, oview);
of->write_output_view(got_file_offset, got_size, got_view);
}
// Create the PLT section.
void
Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
{
if (this->plt_ == NULL)
{
// Create the GOT sections first.
this->got_section(symtab, layout);
this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
this->got_plt_);
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR),
this->plt_);
}
}
// Create a PLT entry for a global symbol.
void
Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
Symbol* gsym)
{
if (gsym->has_plt_offset())
return;
if (this->plt_ == NULL)
this->make_plt_section(symtab, layout);
this->plt_->add_entry(gsym);
}
// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
void
Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
{
if (this->tls_base_symbol_defined_)
return;
Output_segment* tls_segment = layout->tls_segment();
if (tls_segment != NULL)
{
bool is_exec = parameters->options().output_is_executable();
symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
tls_segment, 0, 0,
elfcpp::STT_TLS,
elfcpp::STB_LOCAL,
elfcpp::STV_HIDDEN, 0,
(is_exec
? Symbol::SEGMENT_END
: Symbol::SEGMENT_START),
true);
}
this->tls_base_symbol_defined_ = true;
}
// Create the reserved PLT and GOT entries for the TLS descriptor resolver.
void
Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
Layout* layout)
{
if (this->plt_ == NULL)
this->make_plt_section(symtab, layout);
if (!this->plt_->has_tlsdesc_entry())
{
// Allocate the TLSDESC_GOT entry.
Output_data_got<64, false>* got = this->got_section(symtab, layout);
unsigned int got_offset = got->add_constant(0);
// Allocate the TLSDESC_PLT entry.
this->plt_->reserve_tlsdesc_entry(got_offset);
}
}
// Create a GOT entry for the TLS module index.
unsigned int
Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
Sized_relobj<64, false>* object)
{
if (this->got_mod_index_offset_ == -1U)
{
gold_assert(symtab != NULL && layout != NULL && object != NULL);
Reloc_section* rela_dyn = this->rela_dyn_section(layout);
Output_data_got<64, false>* got = this->got_section(symtab, layout);
unsigned int got_offset = got->add_constant(0);
rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
got_offset, 0);
got->add_constant(0);
this->got_mod_index_offset_ = got_offset;
}
return this->got_mod_index_offset_;
}
// Optimize the TLS relocation type based on what we know about the
// symbol. IS_FINAL is true if the final address of this symbol is
// known at link time.
tls::Tls_optimization
Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
{
// If we are generating a shared library, then we can't do anything
// in the linker.
if (parameters->options().shared())
return tls::TLSOPT_NONE;
switch (r_type)
{
case elfcpp::R_X86_64_TLSGD:
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
case elfcpp::R_X86_64_TLSDESC_CALL:
// These are General-Dynamic which permits fully general TLS
// access. Since we know that we are generating an executable,
// we can convert this to Initial-Exec. If we also know that
// this is a local symbol, we can further switch to Local-Exec.
if (is_final)
return tls::TLSOPT_TO_LE;
return tls::TLSOPT_TO_IE;
case elfcpp::R_X86_64_TLSLD:
// This is Local-Dynamic, which refers to a local symbol in the
// dynamic TLS block. Since we know that we generating an
// executable, we can switch to Local-Exec.
return tls::TLSOPT_TO_LE;
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
// Another Local-Dynamic reloc.
return tls::TLSOPT_TO_LE;
case elfcpp::R_X86_64_GOTTPOFF:
// These are Initial-Exec relocs which get the thread offset
// from the GOT. If we know that we are linking against the
// local symbol, we can switch to Local-Exec, which links the
// thread offset into the instruction.
if (is_final)
return tls::TLSOPT_TO_LE;
return tls::TLSOPT_NONE;
case elfcpp::R_X86_64_TPOFF32:
// When we already have Local-Exec, there is nothing further we
// can do.
return tls::TLSOPT_NONE;
default:
gold_unreachable();
}
}
// Report an unsupported relocation against a local symbol.
void
Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
unsigned int r_type)
{
gold_error(_("%s: unsupported reloc %u against local symbol"),
object->name().c_str(), r_type);
}
// We are about to emit a dynamic relocation of type R_TYPE. If the
// dynamic linker does not support it, issue an error. The GNU linker
// only issues a non-PIC error for an allocated read-only section.
// Here we know the section is allocated, but we don't know that it is
// read-only. But we check for all the relocation types which the
// glibc dynamic linker supports, so it seems appropriate to issue an
// error even if the section is not read-only.
void
Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
{
switch (r_type)
{
// These are the relocation types supported by glibc for x86_64.
case elfcpp::R_X86_64_RELATIVE:
case elfcpp::R_X86_64_GLOB_DAT:
case elfcpp::R_X86_64_JUMP_SLOT:
case elfcpp::R_X86_64_DTPMOD64:
case elfcpp::R_X86_64_DTPOFF64:
case elfcpp::R_X86_64_TPOFF64:
case elfcpp::R_X86_64_64:
case elfcpp::R_X86_64_32:
case elfcpp::R_X86_64_PC32:
case elfcpp::R_X86_64_COPY:
return;
default:
// This prevents us from issuing more than one error per reloc
// section. But we can still wind up issuing more than one
// error per object file.
if (this->issued_non_pic_error_)
return;
gold_assert(parameters->options().output_is_position_independent());
object->error(_("requires unsupported dynamic reloc; "
"recompile with -fPIC"));
this->issued_non_pic_error_ = true;
return;
case elfcpp::R_X86_64_NONE:
gold_unreachable();
}
}
// Scan a relocation for a local symbol.
inline void
Target_x86_64::Scan::local(const General_options&,
Symbol_table* symtab,
Layout* layout,
Target_x86_64* target,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rela<64, false>& reloc,
unsigned int r_type,
const elfcpp::Sym<64, false>& lsym)
{
switch (r_type)
{
case elfcpp::R_X86_64_NONE:
case elfcpp::R_386_GNU_VTINHERIT:
case elfcpp::R_386_GNU_VTENTRY:
break;
case elfcpp::R_X86_64_64:
// If building a shared library (or a position-independent
// executable), we need to create a dynamic relocation for this
// location. The relocation applied at link time will apply the
// link-time value, so we flag the location with an
// R_X86_64_RELATIVE relocation so the dynamic loader can
// relocate it easily.
if (parameters->options().output_is_position_independent())
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_local_relative(object, r_sym,
elfcpp::R_X86_64_RELATIVE,
output_section, data_shndx,
reloc.get_r_offset(),
reloc.get_r_addend());
}
break;
case elfcpp::R_X86_64_32:
case elfcpp::R_X86_64_32S:
case elfcpp::R_X86_64_16:
case elfcpp::R_X86_64_8:
// If building a shared library (or a position-independent
// executable), we need to create a dynamic relocation for this
// location. We can't use an R_X86_64_RELATIVE relocation
// because that is always a 64-bit relocation.
if (parameters->options().output_is_position_independent())
{
this->check_non_pic(object, r_type);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
if (lsym.get_st_type() != elfcpp::STT_SECTION)
rela_dyn->add_local(object, r_sym, r_type, output_section,
data_shndx, reloc.get_r_offset(),
reloc.get_r_addend());
else
{
gold_assert(lsym.get_st_value() == 0);
unsigned int shndx = lsym.get_st_shndx();
bool is_ordinary;
shndx = object->adjust_sym_shndx(r_sym, shndx,
&is_ordinary);
if (!is_ordinary)
object->error(_("section symbol %u has bad shndx %u"),
r_sym, shndx);
else
rela_dyn->add_local_section(object, shndx,
r_type, output_section,
data_shndx, reloc.get_r_offset(),
reloc.get_r_addend());
}
}
break;
case elfcpp::R_X86_64_PC64:
case elfcpp::R_X86_64_PC32:
case elfcpp::R_X86_64_PC16:
case elfcpp::R_X86_64_PC8:
break;
case elfcpp::R_X86_64_PLT32:
// Since we know this is a local symbol, we can handle this as a
// PC32 reloc.
break;
case elfcpp::R_X86_64_GOTPC32:
case elfcpp::R_X86_64_GOTOFF64:
case elfcpp::R_X86_64_GOTPC64:
case elfcpp::R_X86_64_PLTOFF64:
// We need a GOT section.
target->got_section(symtab, layout);
// For PLTOFF64, we'd normally want a PLT section, but since we
// know this is a local symbol, no PLT is needed.
break;
case elfcpp::R_X86_64_GOT64:
case elfcpp::R_X86_64_GOT32:
case elfcpp::R_X86_64_GOTPCREL64:
case elfcpp::R_X86_64_GOTPCREL:
case elfcpp::R_X86_64_GOTPLT64:
{
// The symbol requires a GOT entry.
Output_data_got<64, false>* got = target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
{
// If we are generating a shared object, we need to add a
// dynamic relocation for this symbol's GOT entry.
if (parameters->options().output_is_position_independent())
{
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
// R_X86_64_RELATIVE assumes a 64-bit relocation.
if (r_type != elfcpp::R_X86_64_GOT32)
rela_dyn->add_local_relative(
object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
else
{
this->check_non_pic(object, r_type);
gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
rela_dyn->add_local(
object, r_sym, r_type, got,
object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
}
}
}
// For GOTPLT64, we'd normally want a PLT section, but since
// we know this is a local symbol, no PLT is needed.
}
break;
case elfcpp::R_X86_64_COPY:
case elfcpp::R_X86_64_GLOB_DAT:
case elfcpp::R_X86_64_JUMP_SLOT:
case elfcpp::R_X86_64_RELATIVE:
// These are outstanding tls relocs, which are unexpected when linking
case elfcpp::R_X86_64_TPOFF64:
case elfcpp::R_X86_64_DTPMOD64:
case elfcpp::R_X86_64_TLSDESC:
gold_error(_("%s: unexpected reloc %u in object file"),
object->name().c_str(), r_type);
break;
// These are initial tls relocs, which are expected when linking
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_X86_64_TLSDESC_CALL:
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
case elfcpp::R_X86_64_TPOFF32: // Local-exec
{
bool output_is_shared = parameters->options().shared();
const tls::Tls_optimization optimized_type
= Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
switch (r_type)
{
case elfcpp::R_X86_64_TLSGD: // General-dynamic
if (optimized_type == tls::TLSOPT_NONE)
{
// Create a pair of GOT entries for the module index and
// dtv-relative offset.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
unsigned int shndx = lsym.get_st_shndx();
bool is_ordinary;
shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
if (!is_ordinary)
object->error(_("local symbol %u has bad shndx %u"),
r_sym, shndx);
else
got->add_local_pair_with_rela(object, r_sym,
shndx,
GOT_TYPE_TLS_PAIR,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_DTPMOD64, 0);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
break;
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
target->define_tls_base_symbol(symtab, layout);
if (optimized_type == tls::TLSOPT_NONE)
{
// Create reserved PLT and GOT entries for the resolver.
target->reserve_tlsdesc_entries(symtab, layout);
// Generate a double GOT entry with an R_X86_64_TLSDESC reloc.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
unsigned int shndx = lsym.get_st_shndx();
bool is_ordinary;
shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
if (!is_ordinary)
object->error(_("local symbol %u has bad shndx %u"),
r_sym, shndx);
else
got->add_local_pair_with_rela(object, r_sym,
shndx,
GOT_TYPE_TLS_DESC,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_TLSDESC, 0);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
break;
case elfcpp::R_X86_64_TLSDESC_CALL:
break;
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
if (optimized_type == tls::TLSOPT_NONE)
{
// Create a GOT entry for the module index.
target->got_mod_index_entry(symtab, layout, object);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
break;
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
break;
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
layout->set_has_static_tls();
if (optimized_type == tls::TLSOPT_NONE)
{
// Create a GOT entry for the tp-relative offset.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_TPOFF64);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
break;
case elfcpp::R_X86_64_TPOFF32: // Local-exec
layout->set_has_static_tls();
if (output_is_shared)
unsupported_reloc_local(object, r_type);
break;
default:
gold_unreachable();
}
}
break;
case elfcpp::R_X86_64_SIZE32:
case elfcpp::R_X86_64_SIZE64:
default:
gold_error(_("%s: unsupported reloc %u against local symbol"),
object->name().c_str(), r_type);
break;
}
}
// Report an unsupported relocation against a global symbol.
void
Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
unsigned int r_type,
Symbol* gsym)
{
gold_error(_("%s: unsupported reloc %u against global symbol %s"),
object->name().c_str(), r_type, gsym->demangled_name().c_str());
}
// Scan a relocation for a global symbol.
inline void
Target_x86_64::Scan::global(const General_options&,
Symbol_table* symtab,
Layout* layout,
Target_x86_64* target,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rela<64, false>& reloc,
unsigned int r_type,
Symbol* gsym)
{
switch (r_type)
{
case elfcpp::R_X86_64_NONE:
case elfcpp::R_386_GNU_VTINHERIT:
case elfcpp::R_386_GNU_VTENTRY:
break;
case elfcpp::R_X86_64_64:
case elfcpp::R_X86_64_32:
case elfcpp::R_X86_64_32S:
case elfcpp::R_X86_64_16:
case elfcpp::R_X86_64_8:
{
// Make a PLT entry if necessary.
if (gsym->needs_plt_entry())
{
target->make_plt_entry(symtab, layout, gsym);
// Since this is not a PC-relative relocation, we may be
// taking the address of a function. In that case we need to
// set the entry in the dynamic symbol table to the address of
// the PLT entry.
if (gsym->is_from_dynobj() && !parameters->options().shared())
gsym->set_needs_dynsym_value();
}
// Make a dynamic relocation if necessary.
if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
{
if (target->may_need_copy_reloc(gsym))
{
target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
}
else if (r_type == elfcpp::R_X86_64_64
&& gsym->can_use_relative_reloc(false))
{
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
output_section, object,
data_shndx, reloc.get_r_offset(),
reloc.get_r_addend());
}
else
{
this->check_non_pic(object, r_type);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_global(gsym, r_type, output_section, object,
data_shndx, reloc.get_r_offset(),
reloc.get_r_addend());
}
}
}
break;
case elfcpp::R_X86_64_PC64:
case elfcpp::R_X86_64_PC32:
case elfcpp::R_X86_64_PC16:
case elfcpp::R_X86_64_PC8:
{
// Make a PLT entry if necessary.
if (gsym->needs_plt_entry())
target->make_plt_entry(symtab, layout, gsym);
// Make a dynamic relocation if necessary.
int flags = Symbol::NON_PIC_REF;
if (gsym->type() == elfcpp::STT_FUNC)
flags |= Symbol::FUNCTION_CALL;
if (gsym->needs_dynamic_reloc(flags))
{
if (target->may_need_copy_reloc(gsym))
{
target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
}
else
{
this->check_non_pic(object, r_type);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_global(gsym, r_type, output_section, object,
data_shndx, reloc.get_r_offset(),
reloc.get_r_addend());
}
}
}
break;
case elfcpp::R_X86_64_GOT64:
case elfcpp::R_X86_64_GOT32:
case elfcpp::R_X86_64_GOTPCREL64:
case elfcpp::R_X86_64_GOTPCREL:
case elfcpp::R_X86_64_GOTPLT64:
{
// The symbol requires a GOT entry.
Output_data_got<64, false>* got = target->got_section(symtab, layout);
if (gsym->final_value_is_known())
got->add_global(gsym, GOT_TYPE_STANDARD);
else
{
// If this symbol is not fully resolved, we need to add a
// dynamic relocation for it.
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
if (gsym->is_from_dynobj()
|| gsym->is_undefined()
|| gsym->is_preemptible())
got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
elfcpp::R_X86_64_GLOB_DAT);
else
{
if (got->add_global(gsym, GOT_TYPE_STANDARD))
rela_dyn->add_global_relative(
gsym, elfcpp::R_X86_64_RELATIVE, got,
gsym->got_offset(GOT_TYPE_STANDARD), 0);
}
}
// For GOTPLT64, we also need a PLT entry (but only if the
// symbol is not fully resolved).
if (r_type == elfcpp::R_X86_64_GOTPLT64
&& !gsym->final_value_is_known())
target->make_plt_entry(symtab, layout, gsym);
}
break;
case elfcpp::R_X86_64_PLT32:
// If the symbol is fully resolved, this is just a PC32 reloc.
// Otherwise we need a PLT entry.
if (gsym->final_value_is_known())
break;
// If building a shared library, we can also skip the PLT entry
// if the symbol is defined in the output file and is protected
// or hidden.
if (gsym->is_defined()
&& !gsym->is_from_dynobj()
&& !gsym->is_preemptible())
break;
target->make_plt_entry(symtab, layout, gsym);
break;
case elfcpp::R_X86_64_GOTPC32:
case elfcpp::R_X86_64_GOTOFF64:
case elfcpp::R_X86_64_GOTPC64:
case elfcpp::R_X86_64_PLTOFF64:
// We need a GOT section.
target->got_section(symtab, layout);
// For PLTOFF64, we also need a PLT entry (but only if the
// symbol is not fully resolved).
if (r_type == elfcpp::R_X86_64_PLTOFF64
&& !gsym->final_value_is_known())
target->make_plt_entry(symtab, layout, gsym);
break;
case elfcpp::R_X86_64_COPY:
case elfcpp::R_X86_64_GLOB_DAT:
case elfcpp::R_X86_64_JUMP_SLOT:
case elfcpp::R_X86_64_RELATIVE:
// These are outstanding tls relocs, which are unexpected when linking
case elfcpp::R_X86_64_TPOFF64:
case elfcpp::R_X86_64_DTPMOD64:
case elfcpp::R_X86_64_TLSDESC:
gold_error(_("%s: unexpected reloc %u in object file"),
object->name().c_str(), r_type);
break;
// These are initial tls relocs, which are expected for global()
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_X86_64_TLSDESC_CALL:
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
case elfcpp::R_X86_64_TPOFF32: // Local-exec
{
const bool is_final = gsym->final_value_is_known();
const tls::Tls_optimization optimized_type
= Target_x86_64::optimize_tls_reloc(is_final, r_type);
switch (r_type)
{
case elfcpp::R_X86_64_TLSGD: // General-dynamic
if (optimized_type == tls::TLSOPT_NONE)
{
// Create a pair of GOT entries for the module index and
// dtv-relative offset.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_DTPMOD64,
elfcpp::R_X86_64_DTPOFF64);
}
else if (optimized_type == tls::TLSOPT_TO_IE)
{
// Create a GOT entry for the tp-relative offset.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_TPOFF64);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_global(object, r_type, gsym);
break;
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
target->define_tls_base_symbol(symtab, layout);
if (optimized_type == tls::TLSOPT_NONE)
{
// Create reserved PLT and GOT entries for the resolver.
target->reserve_tlsdesc_entries(symtab, layout);
// Create a double GOT entry with an R_X86_64_TLSDESC reloc.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_TLSDESC, 0);
}
else if (optimized_type == tls::TLSOPT_TO_IE)
{
// Create a GOT entry for the tp-relative offset.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_TPOFF64);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_global(object, r_type, gsym);
break;
case elfcpp::R_X86_64_TLSDESC_CALL:
break;
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
if (optimized_type == tls::TLSOPT_NONE)
{
// Create a GOT entry for the module index.
target->got_mod_index_entry(symtab, layout, object);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_global(object, r_type, gsym);
break;
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
break;
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
layout->set_has_static_tls();
if (optimized_type == tls::TLSOPT_NONE)
{
// Create a GOT entry for the tp-relative offset.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
target->rela_dyn_section(layout),
elfcpp::R_X86_64_TPOFF64);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_global(object, r_type, gsym);
break;
case elfcpp::R_X86_64_TPOFF32: // Local-exec
layout->set_has_static_tls();
if (parameters->options().shared())
unsupported_reloc_local(object, r_type);
break;
default:
gold_unreachable();
}
}
break;
case elfcpp::R_X86_64_SIZE32:
case elfcpp::R_X86_64_SIZE64:
default:
gold_error(_("%s: unsupported reloc %u against global symbol %s"),
object->name().c_str(), r_type,
gsym->demangled_name().c_str());
break;
}
}
void
Target_x86_64::gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_symbols)
{
if (sh_type == elfcpp::SHT_REL)
{
return;
}
gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
Target_x86_64::Scan>(
options,
symtab,
layout,
this,
object,
data_shndx,
prelocs,
reloc_count,
output_section,
needs_special_offset_handling,
local_symbol_count,
plocal_symbols);
}
// Scan relocations for a section.
void
Target_x86_64::scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_symbols)
{
if (sh_type == elfcpp::SHT_REL)
{
gold_error(_("%s: unsupported REL reloc section"),
object->name().c_str());
return;
}
gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
Target_x86_64::Scan>(
options,
symtab,
layout,
this,
object,
data_shndx,
prelocs,
reloc_count,
output_section,
needs_special_offset_handling,
local_symbol_count,
plocal_symbols);
}
// Finalize the sections.
void
Target_x86_64::do_finalize_sections(Layout* layout)
{
// Fill in some more dynamic tags.
Output_data_dynamic* const odyn = layout->dynamic_data();
if (odyn != NULL)
{
if (this->got_plt_ != NULL)
odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
if (this->plt_ != NULL)
{
const Output_data* od = this->plt_->rel_plt();
odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
odyn->add_section_address(elfcpp::DT_JMPREL, od);
odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
if (this->plt_->has_tlsdesc_entry())
{
unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
this->got_->finalize_data_size();
odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
this->plt_, plt_offset);
odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
this->got_, got_offset);
}
}
if (this->rela_dyn_ != NULL)
{
const Output_data* od = this->rela_dyn_;
odyn->add_section_address(elfcpp::DT_RELA, od);
odyn->add_section_size(elfcpp::DT_RELASZ, od);
odyn->add_constant(elfcpp::DT_RELAENT,
elfcpp::Elf_sizes<64>::rela_size);
}
if (!parameters->options().shared())
{
// The value of the DT_DEBUG tag is filled in by the dynamic
// linker at run time, and used by the debugger.
odyn->add_constant(elfcpp::DT_DEBUG, 0);
}
}
// Emit any relocs we saved in an attempt to avoid generating COPY
// relocs.
if (this->copy_relocs_.any_saved_relocs())
this->copy_relocs_.emit(this->rela_dyn_section(layout));
}
// Perform a relocation.
inline bool
Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
Target_x86_64* target,
Output_section*,
size_t relnum,
const elfcpp::Rela<64, false>& rela,
unsigned int r_type,
const Sized_symbol<64>* gsym,
const Symbol_value<64>* psymval,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr address,
section_size_type view_size)
{
if (this->skip_call_tls_get_addr_)
{
if ((r_type != elfcpp::R_X86_64_PLT32
&& r_type != elfcpp::R_X86_64_PC32)
|| gsym == NULL
|| strcmp(gsym->name(), "__tls_get_addr") != 0)
{
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("missing expected TLS relocation"));
}
else
{
this->skip_call_tls_get_addr_ = false;
return false;
}
}
// Pick the value to use for symbols defined in shared objects.
Symbol_value<64> symval;
if (gsym != NULL
&& gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
|| r_type == elfcpp::R_X86_64_PC32
|| r_type == elfcpp::R_X86_64_PC16
|| r_type == elfcpp::R_X86_64_PC8))
{
symval.set_output_value(target->plt_section()->address()
+ gsym->plt_offset());
psymval = &symval;
}
const Sized_relobj<64, false>* object = relinfo->object;
const elfcpp::Elf_Xword addend = rela.get_r_addend();
// Get the GOT offset if needed.
// The GOT pointer points to the end of the GOT section.
// We need to subtract the size of the GOT section to get
// the actual offset to use in the relocation.
bool have_got_offset = false;
unsigned int got_offset = 0;
switch (r_type)
{
case elfcpp::R_X86_64_GOT32:
case elfcpp::R_X86_64_GOT64:
case elfcpp::R_X86_64_GOTPLT64:
case elfcpp::R_X86_64_GOTPCREL:
case elfcpp::R_X86_64_GOTPCREL64:
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
- target->got_size());
}
have_got_offset = true;
break;
default:
break;
}
switch (r_type)
{
case elfcpp::R_X86_64_NONE:
case elfcpp::R_386_GNU_VTINHERIT:
case elfcpp::R_386_GNU_VTENTRY:
break;
case elfcpp::R_X86_64_64:
Relocate_functions<64, false>::rela64(view, object, psymval, addend);
break;
case elfcpp::R_X86_64_PC64:
Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
address);
break;
case elfcpp::R_X86_64_32:
// FIXME: we need to verify that value + addend fits into 32 bits:
// uint64_t x = value + addend;
// x == static_cast<uint64_t>(static_cast<uint32_t>(x))
// Likewise for other <=32-bit relocations (but see R_X86_64_32S).
Relocate_functions<64, false>::rela32(view, object, psymval, addend);
break;
case elfcpp::R_X86_64_32S:
// FIXME: we need to verify that value + addend fits into 32 bits:
// int64_t x = value + addend; // note this quantity is signed!
// x == static_cast<int64_t>(static_cast<int32_t>(x))
Relocate_functions<64, false>::rela32(view, object, psymval, addend);
break;
case elfcpp::R_X86_64_PC32:
Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
address);
break;
case elfcpp::R_X86_64_16:
Relocate_functions<64, false>::rela16(view, object, psymval, addend);
break;
case elfcpp::R_X86_64_PC16:
Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
address);
break;
case elfcpp::R_X86_64_8:
Relocate_functions<64, false>::rela8(view, object, psymval, addend);
break;
case elfcpp::R_X86_64_PC8:
Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
address);
break;
case elfcpp::R_X86_64_PLT32:
gold_assert(gsym == NULL
|| gsym->has_plt_offset()
|| gsym->final_value_is_known()
|| (gsym->is_defined()
&& !gsym->is_from_dynobj()
&& !gsym->is_preemptible()));
// Note: while this code looks the same as for R_X86_64_PC32, it
// behaves differently because psymval was set to point to
// the PLT entry, rather than the symbol, in Scan::global().
Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
address);
break;
case elfcpp::R_X86_64_PLTOFF64:
{
gold_assert(gsym);
gold_assert(gsym->has_plt_offset()
|| gsym->final_value_is_known());
elfcpp::Elf_types<64>::Elf_Addr got_address;
got_address = target->got_section(NULL, NULL)->address();
Relocate_functions<64, false>::rela64(view, object, psymval,
addend - got_address);
}
case elfcpp::R_X86_64_GOT32:
gold_assert(have_got_offset);
Relocate_functions<64, false>::rela32(view, got_offset, addend);
break;
case elfcpp::R_X86_64_GOTPC32:
{
gold_assert(gsym);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_plt_section()->address();
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
}
break;
case elfcpp::R_X86_64_GOT64:
// The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
// Since we always add a PLT entry, this is equivalent.
case elfcpp::R_X86_64_GOTPLT64:
gold_assert(have_got_offset);
Relocate_functions<64, false>::rela64(view, got_offset, addend);
break;
case elfcpp::R_X86_64_GOTPC64:
{
gold_assert(gsym);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_plt_section()->address();
Relocate_functions<64, false>::pcrela64(view, value, addend, address);
}
break;
case elfcpp::R_X86_64_GOTOFF64:
{
elfcpp::Elf_types<64>::Elf_Addr value;
value = (psymval->value(object, 0)
- target->got_plt_section()->address());
Relocate_functions<64, false>::rela64(view, value, addend);
}
break;
case elfcpp::R_X86_64_GOTPCREL:
{
gold_assert(have_got_offset);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
}
break;
case elfcpp::R_X86_64_GOTPCREL64:
{
gold_assert(have_got_offset);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela64(view, value, addend, address);
}
break;
case elfcpp::R_X86_64_COPY:
case elfcpp::R_X86_64_GLOB_DAT:
case elfcpp::R_X86_64_JUMP_SLOT:
case elfcpp::R_X86_64_RELATIVE:
// These are outstanding tls relocs, which are unexpected when linking
case elfcpp::R_X86_64_TPOFF64:
case elfcpp::R_X86_64_DTPMOD64:
case elfcpp::R_X86_64_TLSDESC:
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("unexpected reloc %u in object file"),
r_type);
break;
// These are initial tls relocs, which are expected when linking
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_X86_64_TLSDESC_CALL:
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
case elfcpp::R_X86_64_TPOFF32: // Local-exec
this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
view, address, view_size);
break;
case elfcpp::R_X86_64_SIZE32:
case elfcpp::R_X86_64_SIZE64:
default:
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("unsupported reloc %u"),
r_type);
break;
}
return true;
}
// Perform a TLS relocation.
inline void
Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
Target_x86_64* target,
size_t relnum,
const elfcpp::Rela<64, false>& rela,
unsigned int r_type,
const Sized_symbol<64>* gsym,
const Symbol_value<64>* psymval,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr address,
section_size_type view_size)
{
Output_segment* tls_segment = relinfo->layout->tls_segment();
const Sized_relobj<64, false>* object = relinfo->object;
const elfcpp::Elf_Xword addend = rela.get_r_addend();
elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
const bool is_final = (gsym == NULL
? !parameters->options().output_is_position_independent()
: gsym->final_value_is_known());
const tls::Tls_optimization optimized_type
= Target_x86_64::optimize_tls_reloc(is_final, r_type);
switch (r_type)
{
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
this->saw_tls_block_reloc_ = true;
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
this->tls_gd_to_le(relinfo, relnum, tls_segment,
rela, r_type, value, view,
view_size);
break;
}
else
{
unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
? GOT_TYPE_TLS_OFFSET
: GOT_TYPE_TLS_PAIR);
unsigned int got_offset;
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset(got_type));
got_offset = gsym->got_offset(got_type) - target->got_size();
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
gold_assert(object->local_has_got_offset(r_sym, got_type));
got_offset = (object->local_got_offset(r_sym, got_type)
- target->got_size());
}
if (optimized_type == tls::TLSOPT_TO_IE)
{
gold_assert(tls_segment != NULL);
value = target->got_plt_section()->address() + got_offset;
this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
value, view, address, view_size);
break;
}
else if (optimized_type == tls::TLSOPT_NONE)
{
// Relocate the field with the offset of the pair of GOT
// entries.
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela32(view, value, addend,
address);
break;
}
}
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("unsupported reloc %u"), r_type);
break;
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_X86_64_TLSDESC_CALL:
this->saw_tls_block_reloc_ = true;
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
rela, r_type, value, view,
view_size);
break;
}
else
{
unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
? GOT_TYPE_TLS_OFFSET
: GOT_TYPE_TLS_DESC);
unsigned int got_offset;
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset(got_type));
got_offset = gsym->got_offset(got_type) - target->got_size();
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
gold_assert(object->local_has_got_offset(r_sym, got_type));
got_offset = (object->local_got_offset(r_sym, got_type)
- target->got_size());
}
if (optimized_type == tls::TLSOPT_TO_IE)
{
gold_assert(tls_segment != NULL);
value = target->got_plt_section()->address() + got_offset;
this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
rela, r_type, value, view, address,
view_size);
break;
}
else if (optimized_type == tls::TLSOPT_NONE)
{
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
{
// Relocate the field with the offset of the pair of GOT
// entries.
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela32(view, value, addend,
address);
}
break;
}
}
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("unsupported reloc %u"), r_type);
break;
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
this->saw_tls_block_reloc_ = true;
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
value, view, view_size);
break;
}
else if (optimized_type == tls::TLSOPT_NONE)
{
// Relocate the field with the offset of the GOT entry for
// the module index.
unsigned int got_offset;
got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
- target->got_size());
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela32(view, value, addend,
address);
break;
}
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("unsupported reloc %u"), r_type);
break;
case elfcpp::R_X86_64_DTPOFF32:
gold_assert(tls_segment != NULL);
if (optimized_type == tls::TLSOPT_TO_LE)
{
// This relocation type is used in debugging information.
// In that case we need to not optimize the value. If we
// haven't seen a TLSLD reloc, then we assume we should not
// optimize this reloc.
if (this->saw_tls_block_reloc_)
value -= tls_segment->memsz();
}
Relocate_functions<64, false>::rela32(view, value, addend);
break;
case elfcpp::R_X86_64_DTPOFF64:
gold_assert(tls_segment != NULL);
if (optimized_type == tls::TLSOPT_TO_LE)
{
// See R_X86_64_DTPOFF32, just above, for why we test this.
if (this->saw_tls_block_reloc_)
value -= tls_segment->memsz();
}
Relocate_functions<64, false>::rela64(view, value, addend);
break;
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
rela, r_type, value, view,
view_size);
break;
}
else if (optimized_type == tls::TLSOPT_NONE)
{
// Relocate the field with the offset of the GOT entry for
// the tp-relative offset of the symbol.
unsigned int got_offset;
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
- target->got_size());
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
gold_assert(object->local_has_got_offset(r_sym,
GOT_TYPE_TLS_OFFSET));
got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
- target->got_size());
}
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
break;
}
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
_("unsupported reloc type %u"),
r_type);
break;
case elfcpp::R_X86_64_TPOFF32: // Local-exec
value -= tls_segment->memsz();
Relocate_functions<64, false>::rela32(view, value, addend);
break;
}
}
// Do a relocation in which we convert a TLS General-Dynamic to an
// Initial-Exec.
inline void
Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
size_t relnum,
Output_segment*,
const elfcpp::Rela<64, false>& rela,
unsigned int,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr address,
section_size_type view_size)
{
// .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
// .word 0x6666; rex64; call __tls_get_addr
// ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
(memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
(memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
const elfcpp::Elf_Xword addend = rela.get_r_addend();
Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
// The next reloc should be a PLT32 reloc against __tls_get_addr.
// We can skip it.
this->skip_call_tls_get_addr_ = true;
}
// Do a relocation in which we convert a TLS General-Dynamic to a
// Local-Exec.
inline void
Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>& rela,
unsigned int,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size)
{
// .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
// .word 0x6666; rex64; call __tls_get_addr
// ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
(memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
(memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
value -= tls_segment->memsz();
Relocate_functions<64, false>::rela32(view + 8, value, 0);
// The next reloc should be a PLT32 reloc against __tls_get_addr.
// We can skip it.
this->skip_call_tls_get_addr_ = true;
}
// Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
inline void
Target_x86_64::Relocate::tls_desc_gd_to_ie(
const Relocate_info<64, false>* relinfo,
size_t relnum,
Output_segment*,
const elfcpp::Rela<64, false>& rela,
unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr address,
section_size_type view_size)
{
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
{
// leaq foo@tlsdesc(%rip), %rax
// ==> movq foo@gottpoff(%rip), %rax
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
view[-2] = 0x8b;
const elfcpp::Elf_Xword addend = rela.get_r_addend();
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
}
else
{
// call *foo@tlscall(%rax)
// ==> nop; nop
gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
view[0] == 0xff && view[1] == 0x10);
view[0] = 0x66;
view[1] = 0x90;
}
}
// Do a TLSDESC-style General-Dynamic to Local-Exec transition.
inline void
Target_x86_64::Relocate::tls_desc_gd_to_le(
const Relocate_info<64, false>* relinfo,
size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>& rela,
unsigned int r_type,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size)
{
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
{
// leaq foo@tlsdesc(%rip), %rax
// ==> movq foo@tpoff, %rax
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
view[-2] = 0xc7;
view[-1] = 0xc0;
value -= tls_segment->memsz();
Relocate_functions<64, false>::rela32(view, value, 0);
}
else
{
// call *foo@tlscall(%rax)
// ==> nop; nop
gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
view[0] == 0xff && view[1] == 0x10);
view[0] = 0x66;
view[1] = 0x90;
}
}
inline void
Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
size_t relnum,
Output_segment*,
const elfcpp::Rela<64, false>& rela,
unsigned int,
elfcpp::Elf_types<64>::Elf_Addr,
unsigned char* view,
section_size_type view_size)
{
// leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
// ... leq foo@dtpoff(%rax),%reg
// ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
// The next reloc should be a PLT32 reloc against __tls_get_addr.
// We can skip it.
this->skip_call_tls_get_addr_ = true;
}
// Do a relocation in which we convert a TLS Initial-Exec to a
// Local-Exec.
inline void
Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
size_t relnum,
Output_segment* tls_segment,
const elfcpp::Rela<64, false>& rela,
unsigned int,
elfcpp::Elf_types<64>::Elf_Addr value,
unsigned char* view,
section_size_type view_size)
{
// We need to examine the opcodes to figure out which instruction we
// are looking at.
// movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
// addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
unsigned char op1 = view[-3];
unsigned char op2 = view[-2];
unsigned char op3 = view[-1];
unsigned char reg = op3 >> 3;
if (op2 == 0x8b)
{
// movq
if (op1 == 0x4c)
view[-3] = 0x49;
view[-2] = 0xc7;
view[-1] = 0xc0 | reg;
}
else if (reg == 4)
{
// Special handling for %rsp.
if (op1 == 0x4c)
view[-3] = 0x49;
view[-2] = 0x81;
view[-1] = 0xc0 | reg;
}
else
{
// addq
if (op1 == 0x4c)
view[-3] = 0x4d;
view[-2] = 0x8d;
view[-1] = 0x80 | reg | (reg << 3);
}
value -= tls_segment->memsz();
Relocate_functions<64, false>::rela32(view, value, 0);
}
// Relocate section data.
void
Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr address,
section_size_type view_size)
{
gold_assert(sh_type == elfcpp::SHT_RELA);
gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
Target_x86_64::Relocate>(
relinfo,
this,
prelocs,
reloc_count,
output_section,
needs_special_offset_handling,
view,
address,
view_size);
}
// Return the size of a relocation while scanning during a relocatable
// link.
unsigned int
Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
unsigned int r_type,
Relobj* object)
{
switch (r_type)
{
case elfcpp::R_X86_64_NONE:
case elfcpp::R_386_GNU_VTINHERIT:
case elfcpp::R_386_GNU_VTENTRY:
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_X86_64_TLSDESC_CALL:
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
case elfcpp::R_X86_64_DTPOFF32:
case elfcpp::R_X86_64_DTPOFF64:
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
case elfcpp::R_X86_64_TPOFF32: // Local-exec
return 0;
case elfcpp::R_X86_64_64:
case elfcpp::R_X86_64_PC64:
case elfcpp::R_X86_64_GOTOFF64:
case elfcpp::R_X86_64_GOTPC64:
case elfcpp::R_X86_64_PLTOFF64:
case elfcpp::R_X86_64_GOT64:
case elfcpp::R_X86_64_GOTPCREL64:
case elfcpp::R_X86_64_GOTPCREL:
case elfcpp::R_X86_64_GOTPLT64:
return 8;
case elfcpp::R_X86_64_32:
case elfcpp::R_X86_64_32S:
case elfcpp::R_X86_64_PC32:
case elfcpp::R_X86_64_PLT32:
case elfcpp::R_X86_64_GOTPC32:
case elfcpp::R_X86_64_GOT32:
return 4;
case elfcpp::R_X86_64_16:
case elfcpp::R_X86_64_PC16:
return 2;
case elfcpp::R_X86_64_8:
case elfcpp::R_X86_64_PC8:
return 1;
case elfcpp::R_X86_64_COPY:
case elfcpp::R_X86_64_GLOB_DAT:
case elfcpp::R_X86_64_JUMP_SLOT:
case elfcpp::R_X86_64_RELATIVE:
// These are outstanding tls relocs, which are unexpected when linking
case elfcpp::R_X86_64_TPOFF64:
case elfcpp::R_X86_64_DTPMOD64:
case elfcpp::R_X86_64_TLSDESC:
object->error(_("unexpected reloc %u in object file"), r_type);
return 0;
case elfcpp::R_X86_64_SIZE32:
case elfcpp::R_X86_64_SIZE64:
default:
object->error(_("unsupported reloc %u against local symbol"), r_type);
return 0;
}
}
// Scan the relocs during a relocatable link.
void
Target_x86_64::scan_relocatable_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<64, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_symbols,
Relocatable_relocs* rr)
{
gold_assert(sh_type == elfcpp::SHT_RELA);
typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
Relocatable_size_for_reloc> Scan_relocatable_relocs;
gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
Scan_relocatable_relocs>(
options,
symtab,
layout,
object,
data_shndx,
prelocs,
reloc_count,
output_section,
needs_special_offset_handling,
local_symbol_count,
plocal_symbols,
rr);
}
// Relocate a section during a relocatable link.
void
Target_x86_64::relocate_for_relocatable(
const Relocate_info<64, false>* relinfo,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
off_t offset_in_output_section,
const Relocatable_relocs* rr,
unsigned char* view,
elfcpp::Elf_types<64>::Elf_Addr view_address,
section_size_type view_size,
unsigned char* reloc_view,
section_size_type reloc_view_size)
{
gold_assert(sh_type == elfcpp::SHT_RELA);
gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
relinfo,
prelocs,
reloc_count,
output_section,
offset_in_output_section,
rr,
view,
view_address,
view_size,
reloc_view,
reloc_view_size);
}
// Return the value to use for a dynamic which requires special
// treatment. This is how we support equality comparisons of function
// pointers across shared library boundaries, as described in the
// processor specific ABI supplement.
uint64_t
Target_x86_64::do_dynsym_value(const Symbol* gsym) const
{
gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
return this->plt_section()->address() + gsym->plt_offset();
}
// Return a string used to fill a code section with nops to take up
// the specified length.
std::string
Target_x86_64::do_code_fill(section_size_type length) const
{
if (length >= 16)
{
// Build a jmpq instruction to skip over the bytes.
unsigned char jmp[5];
jmp[0] = 0xe9;
elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
+ std::string(length - 5, '\0'));
}
// Nop sequences of various lengths.
const char nop1[1] = { 0x90 }; // nop
const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
0x00 }; // leal 0(%esi,1),%esi
const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
0x00, 0x00 };
const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
0x00, 0x00, 0x00 };
const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
0x00 };
const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
0x00, 0x00 };
const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
0x00, 0x00, 0x00 };
const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
0x00, 0x00, 0x00, 0x00 };
const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
0x27, 0x00, 0x00, 0x00,
0x00 };
const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
0xbc, 0x27, 0x00, 0x00,
0x00, 0x00 };
const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
0x90, 0x90, 0x90, 0x90,
0x90, 0x90, 0x90 };
const char* nops[16] = {
NULL,
nop1, nop2, nop3, nop4, nop5, nop6, nop7,
nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
};
return std::string(nops[length], length);
}
// The selector for x86_64 object files.
class Target_selector_x86_64 : public Target_selector_freebsd
{
public:
Target_selector_x86_64()
: Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
"elf64-x86-64-freebsd")
{ }
Target*
do_instantiate_target()
{ return new Target_x86_64(); }
};
Target_selector_x86_64 target_selector_x86_64;
} // End anonymous namespace.
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