2256 lines
76 KiB
C++
2256 lines
76 KiB
C++
// x86_64.cc -- x86_64 target support for gold.
|
|
|
|
// Copyright 2006, 2007, 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 Library General Public License
|
|
// as published by the Free Software Foundation; either version 2, or
|
|
// (at your option) any later version.
|
|
|
|
// In addition to the permissions in the GNU Library General Public
|
|
// License, the Free Software Foundation gives you unlimited
|
|
// permission to link the compiled version of this file into
|
|
// combinations with other programs, and to distribute those
|
|
// combinations without any restriction coming from the use of this
|
|
// file. (The Library Public License restrictions do apply in other
|
|
// respects; for example, they cover modification of the file, and
|
|
/// distribution when not linked into a combined executable.)
|
|
|
|
// 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
|
|
// Library General Public License for more details.
|
|
|
|
// You should have received a copy of the GNU Library 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 "target.h"
|
|
#include "target-reloc.h"
|
|
#include "target-select.h"
|
|
#include "tls.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 Sized_target<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()
|
|
: Sized_target<64, false>(&x86_64_info),
|
|
got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
|
|
copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U)
|
|
{ }
|
|
|
|
// 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);
|
|
|
|
// Return whether SYM is defined by the ABI.
|
|
bool
|
|
do_is_defined_by_abi(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.
|
|
struct Scan
|
|
{
|
|
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);
|
|
|
|
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*);
|
|
};
|
|
|
|
// The class which implements relocation.
|
|
class Relocate
|
|
{
|
|
public:
|
|
Relocate()
|
|
: skip_call_tls_get_addr_(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*, 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 Local-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,
|
|
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 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_;
|
|
};
|
|
|
|
// 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 a PLT entry for a global symbol.
|
|
void
|
|
make_plt_entry(Symbol_table*, Layout*, Symbol*);
|
|
|
|
// 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->output_is_shared()
|
|
&& gsym->is_from_dynobj()
|
|
&& gsym->type() != elfcpp::STT_FUNC);
|
|
}
|
|
|
|
// Copy a relocation against a global symbol.
|
|
void
|
|
copy_reloc(const General_options*, Symbol_table*, Layout*,
|
|
Sized_relobj<64, false>*, unsigned int,
|
|
Output_section*, Symbol*, const elfcpp::Rela<64, false>&);
|
|
|
|
// Information about this specific target which we pass to the
|
|
// general Target structure.
|
|
static const Target::Target_info x86_64_info;
|
|
|
|
// 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<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_;
|
|
};
|
|
|
|
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
|
|
"/lib/ld64.so.1", // program interpreter
|
|
0x400000, // default_text_segment_address
|
|
0x1000, // abi_pagesize
|
|
0x1000 // common_pagesize
|
|
};
|
|
|
|
// 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>();
|
|
|
|
layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
|
|
this->got_);
|
|
|
|
// 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);
|
|
layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
|
|
this->got_plt_);
|
|
|
|
// 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();
|
|
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_space*);
|
|
|
|
// Add an entry to the PLT.
|
|
void
|
|
add_entry(Symbol* gsym);
|
|
|
|
// Return the .rel.plt section data.
|
|
const Reloc_section*
|
|
rel_plt() const
|
|
{ return this->rel_; }
|
|
|
|
protected:
|
|
void
|
|
do_adjust_output_section(Output_section* os);
|
|
|
|
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];
|
|
|
|
// Set the final size.
|
|
void
|
|
set_final_data_size()
|
|
{ this->set_data_size((this->count_ + 1) * plt_entry_size); }
|
|
|
|
// Write out the PLT data.
|
|
void
|
|
do_write(Output_file*);
|
|
|
|
// The reloc section.
|
|
Reloc_section* rel_;
|
|
// The .got.plt section.
|
|
Output_data_space* got_plt_;
|
|
// The number of PLT entries.
|
|
unsigned int count_;
|
|
};
|
|
|
|
// 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_space* got_plt)
|
|
: Output_section_data(8), got_plt_(got_plt), count_(0)
|
|
{
|
|
this->rel_ = new Reloc_section();
|
|
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)
|
|
{
|
|
// UnixWare sets the entsize of .plt to 4, and so does the old GNU
|
|
// linker, and so do we.
|
|
os->set_entsize(4);
|
|
}
|
|
|
|
// 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.
|
|
}
|
|
|
|
// 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
|
|
};
|
|
|
|
// 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;
|
|
|
|
elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
|
|
elfcpp::Elf_types<32>::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);
|
|
}
|
|
|
|
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 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)
|
|
{
|
|
// Create the GOT sections first.
|
|
this->got_section(symtab, layout);
|
|
|
|
this->plt_ = new Output_data_plt_x86_64(layout, this->got_plt_);
|
|
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_EXECINSTR),
|
|
this->plt_);
|
|
}
|
|
|
|
this->plt_->add_entry(gsym);
|
|
}
|
|
|
|
// 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_;
|
|
}
|
|
|
|
// Handle a relocation against a non-function symbol defined in a
|
|
// dynamic object. The traditional way to handle this is to generate
|
|
// a COPY relocation to copy the variable at runtime from the shared
|
|
// object into the executable's data segment. However, this is
|
|
// undesirable in general, as if the size of the object changes in the
|
|
// dynamic object, the executable will no longer work correctly. If
|
|
// this relocation is in a writable section, then we can create a
|
|
// dynamic reloc and the dynamic linker will resolve it to the correct
|
|
// address at runtime. However, we do not want do that if the
|
|
// relocation is in a read-only section, as it would prevent the
|
|
// readonly segment from being shared. And if we have to eventually
|
|
// generate a COPY reloc, then any dynamic relocations will be
|
|
// useless. So this means that if this is a writable section, we need
|
|
// to save the relocation until we see whether we have to create a
|
|
// COPY relocation for this symbol for any other relocation.
|
|
|
|
void
|
|
Target_x86_64::copy_reloc(const General_options* options,
|
|
Symbol_table* symtab,
|
|
Layout* layout,
|
|
Sized_relobj<64, false>* object,
|
|
unsigned int data_shndx,
|
|
Output_section* output_section,
|
|
Symbol* gsym,
|
|
const elfcpp::Rela<64, false>& rela)
|
|
{
|
|
Sized_symbol<64>* ssym;
|
|
ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(64) (gsym
|
|
SELECT_SIZE(64));
|
|
|
|
if (!Copy_relocs<64, false>::need_copy_reloc(options, object,
|
|
data_shndx, ssym))
|
|
{
|
|
// So far we do not need a COPY reloc. Save this relocation.
|
|
// If it turns out that we never need a COPY reloc for this
|
|
// symbol, then we will emit the relocation.
|
|
if (this->copy_relocs_ == NULL)
|
|
this->copy_relocs_ = new Copy_relocs<64, false>();
|
|
this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela);
|
|
}
|
|
else
|
|
{
|
|
// Allocate space for this symbol in the .bss section.
|
|
|
|
elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize();
|
|
|
|
// There is no defined way to determine the required alignment
|
|
// of the symbol. We pick the alignment based on the size. We
|
|
// set an arbitrary maximum of 256.
|
|
unsigned int align;
|
|
for (align = 1; align < 512; align <<= 1)
|
|
if ((symsize & align) != 0)
|
|
break;
|
|
|
|
if (this->dynbss_ == NULL)
|
|
{
|
|
this->dynbss_ = new Output_data_space(align);
|
|
layout->add_output_section_data(".bss",
|
|
elfcpp::SHT_NOBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->dynbss_);
|
|
}
|
|
|
|
Output_data_space* dynbss = this->dynbss_;
|
|
|
|
if (align > dynbss->addralign())
|
|
dynbss->set_space_alignment(align);
|
|
|
|
section_size_type dynbss_size = dynbss->current_data_size();
|
|
dynbss_size = align_address(dynbss_size, align);
|
|
section_size_type offset = dynbss_size;
|
|
dynbss->set_current_data_size(dynbss_size + symsize);
|
|
|
|
symtab->define_with_copy_reloc(ssym, dynbss, offset);
|
|
|
|
// Add the COPY reloc.
|
|
Reloc_section* rela_dyn = this->rela_dyn_section(layout);
|
|
rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0);
|
|
}
|
|
}
|
|
|
|
|
|
// 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->output_is_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);
|
|
}
|
|
|
|
// 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->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->output_is_position_independent())
|
|
{
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
if (lsym.get_st_type() != elfcpp::STT_SECTION)
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
|
|
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);
|
|
rela_dyn->add_local_section(object, lsym.get_st_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))
|
|
{
|
|
// If we are generating a shared object, we need to add a
|
|
// dynamic relocation for this symbol's GOT entry.
|
|
if (parameters->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),
|
|
0);
|
|
else
|
|
{
|
|
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),
|
|
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->output_is_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());
|
|
got->add_local_tls_with_rela(object, r_sym,
|
|
lsym.get_st_shndx(), true,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_DTPMOD64);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
// FIXME: If not relaxing to LE, we need to generate
|
|
// a GOT entry with a R_x86_64_TLSDESC reloc.
|
|
if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
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,
|
|
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& 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->output_is_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(&options, 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
|
|
{
|
|
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(&options, symtab, layout, object,
|
|
data_shndx, output_section, gsym, reloc);
|
|
}
|
|
else
|
|
{
|
|
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);
|
|
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, rela_dyn,
|
|
elfcpp::R_X86_64_GLOB_DAT);
|
|
else
|
|
{
|
|
if (got->add_global(gsym))
|
|
rela_dyn->add_global_relative(gsym,
|
|
elfcpp::R_X86_64_RELATIVE,
|
|
got, gsym->got_offset(), 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_tls_with_rela(gsym,
|
|
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,
|
|
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:
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
// FIXME: If not relaxing to LE, we need to generate
|
|
// DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
|
|
if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
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,
|
|
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->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 global symbol %s"),
|
|
object->name().c_str(), r_type,
|
|
gsym->demangled_name().c_str());
|
|
break;
|
|
}
|
|
}
|
|
|
|
// 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->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->output_is_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_ == NULL)
|
|
return;
|
|
if (this->copy_relocs_->any_to_emit())
|
|
{
|
|
Reloc_section* rela_dyn = this->rela_dyn_section(layout);
|
|
this->copy_relocs_->emit(rela_dyn);
|
|
}
|
|
delete this->copy_relocs_;
|
|
this->copy_relocs_ = NULL;
|
|
}
|
|
|
|
// Perform a relocation.
|
|
|
|
inline bool
|
|
Target_x86_64::Relocate::relocate(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)
|
|
{
|
|
if (this->skip_call_tls_get_addr_)
|
|
{
|
|
if (r_type != elfcpp::R_X86_64_PLT32
|
|
|| 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->is_from_dynobj()
|
|
|| (parameters->output_is_shared()
|
|
&& (gsym->is_undefined() || gsym->is_preemptible())))
|
|
&& gsym->has_plt_offset())
|
|
{
|
|
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_offset = gsym->got_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_offset = object->local_got_offset(r_sym) - 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->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
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
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_offset;
|
|
if (gsym != NULL)
|
|
{
|
|
gold_assert(gsym->has_tls_got_offset(true));
|
|
got_offset = gsym->tls_got_offset(true) - target->got_size();
|
|
}
|
|
else
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
|
|
gold_assert(object->local_has_tls_got_offset(r_sym, true));
|
|
got_offset = (object->local_tls_got_offset(r_sym, true)
|
|
- target->got_size());
|
|
}
|
|
if (optimized_type == tls::TLSOPT_TO_IE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
|
|
got_offset, view, 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_TLSLD: // Local-dynamic
|
|
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)
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<64, false>::rela32(view, value, 0);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
gold_assert(tls_segment != NULL);
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<64, false>::rela64(view, value, 0);
|
|
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_offset = gsym->got_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_offset = (object->local_got_offset(r_sym)
|
|
- 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, 0);
|
|
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* 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; 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);
|
|
|
|
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 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;
|
|
}
|
|
|
|
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, Target_x86_64, 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, Target_x86_64, 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)
|
|
{
|
|
if (length >= 16)
|
|
{
|
|
// Build a jmpq instruction to skip over the bytes.
|
|
unsigned char jmp[5];
|
|
jmp[0] = 0xe9;
|
|
elfcpp::Swap_unaligned<64, 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
|
|
{
|
|
public:
|
|
Target_selector_x86_64()
|
|
: Target_selector(elfcpp::EM_X86_64, 64, false)
|
|
{ }
|
|
|
|
Target*
|
|
recognize(int machine, int osabi, int abiversion);
|
|
|
|
Target*
|
|
recognize_by_name(const char*);
|
|
|
|
private:
|
|
Target_x86_64* target_;
|
|
};
|
|
|
|
// Recognize an x86_64 object file when we already know that the machine
|
|
// number is EM_X86_64.
|
|
|
|
Target*
|
|
Target_selector_x86_64::recognize(int, int, int)
|
|
{
|
|
if (this->target_ == NULL)
|
|
this->target_ = new Target_x86_64();
|
|
return this->target_;
|
|
}
|
|
|
|
Target*
|
|
Target_selector_x86_64::recognize_by_name(const char* name)
|
|
{
|
|
if (strcmp(name, "elf64-x86-64") != 0)
|
|
return NULL;
|
|
if (this->target_ == NULL)
|
|
this->target_ = new Target_x86_64();
|
|
return this->target_;
|
|
}
|
|
|
|
Target_selector_x86_64 target_selector_x86_64;
|
|
|
|
} // End anonymous namespace.
|