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binutils-gdb/gold/aarch64.cc

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// aarch64.cc -- aarch64 target support for gold.
// Copyright (C) 2014 Free Software Foundation, Inc.
// Written by Jing Yu <jingyu@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 "dwarf.h"
#include "parameters.h"
#include "reloc.h"
#include "aarch64.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"
#include "nacl.h"
#include "gc.h"
#include "icf.h"
// The first three .got.plt entries are reserved.
const int32_t AARCH64_GOTPLT_RESERVE_COUNT = 3;
namespace
{
using namespace gold;
template<int size, bool big_endian>
class Output_data_plt_aarch64;
template<int size, bool big_endian>
class Output_data_plt_aarch64_standard;
template<int size, bool big_endian>
class Target_aarch64;
// Output_data_got_aarch64 class.
template<int size, bool big_endian>
class Output_data_got_aarch64 : public Output_data_got<size, big_endian>
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Valtype;
Output_data_got_aarch64(Symbol_table* symtab, Layout* layout)
: Output_data_got<size, big_endian>(), layout_(layout)
{ }
protected:
// Write out the GOT table.
void
do_write(Output_file* of) {
// The first entry in the GOT is the address of the .dynamic section.
gold_assert(this->data_size() >= size / 8);
Output_section* dynamic = this->layout_->dynamic_section();
Valtype dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
this->replace_constant(0, dynamic_addr);
Output_data_got<size, big_endian>::do_write(of);
}
private:
// A pointer to the Layout class, so that we can find the .dynamic
// section when we write out the GOT section.
Layout* layout_;
};
// The aarch64 target class.
// See the ABI at
// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0056b/IHI0056B_aaelf64.pdf
template<int size, bool big_endian>
class Target_aarch64 : public Sized_target<size, big_endian>
{
public:
typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>
Reloc_section;
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
Target_aarch64(const Target::Target_info* info = &aarch64_info)
: Sized_target<size, big_endian>(info),
got_(NULL), plt_(NULL), got_plt_(NULL),
global_offset_table_(NULL), rela_dyn_(NULL),
copy_relocs_(elfcpp::R_AARCH64_COPY)
{ }
// Scan the relocations to determine unreferenced sections for
// garbage collection.
void
gc_process_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj_file<size, big_endian>* 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(Symbol_table* symtab,
Layout* layout,
Sized_relobj_file<size, big_endian>* 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*, const Input_objects*, Symbol_table*);
// Relocate a section.
void
relocate_section(const Relocate_info<size, big_endian>*,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr view_address,
section_size_type view_size,
const Reloc_symbol_changes*);
// Scan the relocs during a relocatable link.
void
scan_relocatable_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj_file<size, big_endian>* 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_relocs(
const Relocate_info<size, big_endian>*,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
const Relocatable_relocs*,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr view_address,
section_size_type view_size,
unsigned char* reloc_view,
section_size_type reloc_view_size);
// Return the number of entries in the PLT.
unsigned int
plt_entry_count() const;
//Return the offset of the first non-reserved PLT entry.
unsigned int
first_plt_entry_offset() const;
// Return the size of each PLT entry.
unsigned int
plt_entry_size() const;
private:
// The class which scans relocations.
class Scan
{
public:
Scan()
: issued_non_pic_error_(false)
{ }
static inline int
get_reference_flags(unsigned int r_type);
inline void
local(Symbol_table* symtab, Layout* layout, Target_aarch64* target,
Sized_relobj_file<size, big_endian>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rela<size, big_endian>& reloc, unsigned int r_type,
const elfcpp::Sym<size, big_endian>& lsym,
bool is_discarded);
inline void
global(Symbol_table* symtab, Layout* layout, Target_aarch64* target,
Sized_relobj_file<size, big_endian>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rela<size, big_endian>& reloc, unsigned int r_type,
Symbol* gsym);
inline bool
local_reloc_may_be_function_pointer(Symbol_table* , Layout* ,
Target_aarch64<size, big_endian>* ,
Sized_relobj_file<size, big_endian>* ,
unsigned int ,
Output_section* ,
const elfcpp::Rela<size, big_endian>& ,
unsigned int r_type,
const elfcpp::Sym<size, big_endian>&);
inline bool
global_reloc_may_be_function_pointer(Symbol_table* , Layout* ,
Target_aarch64<size, big_endian>* ,
Sized_relobj_file<size, big_endian>* ,
unsigned int ,
Output_section* ,
const elfcpp::Rela<size, big_endian>& ,
unsigned int r_type,
Symbol* gsym);
private:
static void
unsupported_reloc_local(Sized_relobj_file<size, big_endian>*,
unsigned int r_type);
static void
unsupported_reloc_global(Sized_relobj_file<size, big_endian>*,
unsigned int r_type, Symbol*);
inline bool
possible_function_pointer_reloc(unsigned int r_type);
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()
{ }
~Relocate()
{ }
// Do a relocation. Return false if the caller should not issue
// any warnings about this relocation.
inline bool
relocate(const Relocate_info<size, big_endian>*, Target_aarch64*,
Output_section*,
size_t relnum, const elfcpp::Rela<size, big_endian>&,
unsigned int r_type, const Sized_symbol<size>*,
const Symbol_value<size>*,
unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
section_size_type);
};
// 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_aarch64<size, big_endian>*
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*);
// Get the PLT section.
Output_data_plt_aarch64<size, big_endian>*
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*);
// Add a potential copy relocation.
void
copy_reloc(Symbol_table* symtab, Layout* layout,
Sized_relobj_file<size, big_endian>* object,
unsigned int shndx, Output_section* output_section,
Symbol* sym, const elfcpp::Rela<size, big_endian>& reloc)
{
this->copy_relocs_.copy_reloc(symtab, layout,
symtab->get_sized_symbol<size>(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 aarch64_info;
// The types of GOT entries needed for this platform.
// These values are exposed to the ABI in an incremental link.
// Do not renumber existing values without changing the version
// number of the .gnu_incremental_inputs section.
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_aarch64<size, big_endian>* got_;
// The PLT section.
Output_data_plt_aarch64<size, big_endian>* plt_;
// The GOT PLT section.
Output_data_space* got_plt_;
// The _GLOBAL_OFFSET_TABLE_ symbol.
Symbol* global_offset_table_;
// The dynamic reloc section.
Reloc_section* rela_dyn_;
// Relocs saved to avoid a COPY reloc.
Copy_relocs<elfcpp::SHT_RELA, size, big_endian> copy_relocs_;
};
template<>
const Target::Target_info Target_aarch64<64, false>::aarch64_info =
{
64, // size
false, // is_big_endian
elfcpp::EM_AARCH64, // machine_code
false, // has_make_symbol
false, // has_resolve
false, // has_code_fill
true, // is_default_stack_executable
false, // can_icf_inline_merge_sections
'\0', // wrap_char
"/lib/ld.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)
false, // isolate_execinstr
0, // rosegment_gap
elfcpp::SHN_UNDEF, // small_common_shndx
elfcpp::SHN_UNDEF, // large_common_shndx
0, // small_common_section_flags
0, // large_common_section_flags
NULL, // attributes_section
NULL, // attributes_vendor
"_start" // entry_symbol_name
};
template<>
const Target::Target_info Target_aarch64<32, false>::aarch64_info =
{
32, // size
false, // is_big_endian
elfcpp::EM_AARCH64, // machine_code
false, // has_make_symbol
false, // has_resolve
false, // has_code_fill
true, // is_default_stack_executable
false, // can_icf_inline_merge_sections
'\0', // wrap_char
"/lib/ld.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)
false, // isolate_execinstr
0, // rosegment_gap
elfcpp::SHN_UNDEF, // small_common_shndx
elfcpp::SHN_UNDEF, // large_common_shndx
0, // small_common_section_flags
0, // large_common_section_flags
NULL, // attributes_section
NULL, // attributes_vendor
"_start" // entry_symbol_name
};
template<>
const Target::Target_info Target_aarch64<64, true>::aarch64_info =
{
64, // size
true, // is_big_endian
elfcpp::EM_AARCH64, // machine_code
false, // has_make_symbol
false, // has_resolve
false, // has_code_fill
true, // is_default_stack_executable
false, // can_icf_inline_merge_sections
'\0', // wrap_char
"/lib/ld.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)
false, // isolate_execinstr
0, // rosegment_gap
elfcpp::SHN_UNDEF, // small_common_shndx
elfcpp::SHN_UNDEF, // large_common_shndx
0, // small_common_section_flags
0, // large_common_section_flags
NULL, // attributes_section
NULL, // attributes_vendor
"_start" // entry_symbol_name
};
template<>
const Target::Target_info Target_aarch64<32, true>::aarch64_info =
{
32, // size
true, // is_big_endian
elfcpp::EM_AARCH64, // machine_code
false, // has_make_symbol
false, // has_resolve
false, // has_code_fill
true, // is_default_stack_executable
false, // can_icf_inline_merge_sections
'\0', // wrap_char
"/lib/ld.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)
false, // isolate_execinstr
0, // rosegment_gap
elfcpp::SHN_UNDEF, // small_common_shndx
elfcpp::SHN_UNDEF, // large_common_shndx
0, // small_common_section_flags
0, // large_common_section_flags
NULL, // attributes_section
NULL, // attributes_vendor
"_start" // entry_symbol_name
};
// Get the GOT section, creating it if necessary.
template<int size, bool big_endian>
Output_data_got_aarch64<size, big_endian>*
Target_aarch64<size, big_endian>::got_section(Symbol_table* symtab,
Layout* layout)
{
if (this->got_ == NULL)
{
gold_assert(symtab != NULL && layout != NULL);
// When using -z now, we can treat .got.plt as a relro section.
// Without -z now, it is modified after program startup by lazy
// PLT relocations.
bool is_got_plt_relro = parameters->options().now();
Output_section_order got_order = (is_got_plt_relro
? ORDER_RELRO
: ORDER_RELRO_LAST);
Output_section_order got_plt_order = (is_got_plt_relro
? ORDER_RELRO
: ORDER_NON_RELRO_FIRST);
// Layout of .got and .got.plt sections.
// .got[0] &_DYNAMIC <-_GLOBAL_OFFSET_TABLE_
// ...
// .gotplt[0] reserved for ld.so (&linkmap) <--DT_PLTGOT
// .gotplt[1] reserved for ld.so (resolver)
// .gotplt[2] reserved
// Generate .got section.
this->got_ = new Output_data_got_aarch64<size, big_endian>(symtab,
layout);
layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE),
this->got_, got_order, true);
// The first word of GOT is reserved for the address of .dynamic.
// We put 0 here now. The value will be replaced later in
// Output_data_got_aarch64::do_write.
this->got_->add_constant(0);
// Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
// _GLOBAL_OFFSET_TABLE_ value points to the start of the .got section,
// even if there is a .got.plt section.
this->global_offset_table_ =
symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
Symbol_table::PREDEFINED,
this->got_,
0, 0, elfcpp::STT_OBJECT,
elfcpp::STB_LOCAL,
elfcpp::STV_HIDDEN, 0,
false, false);
// Generate .got.plt section.
this->got_plt_ = new Output_data_space(size / 8, "** GOT PLT");
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
this->got_plt_, got_plt_order,
is_got_plt_relro);
// The first three entries are reserved.
this->got_plt_->set_current_data_size
(AARCH64_GOTPLT_RESERVE_COUNT * (size / 8));
if (!is_got_plt_relro)
{
// Those bytes can go into the relro segment.
layout->increase_relro
(AARCH64_GOTPLT_RESERVE_COUNT * (size / 8));
}
}
return this->got_;
}
// Get the dynamic reloc section, creating it if necessary.
template<int size, bool big_endian>
typename Target_aarch64<size, big_endian>::Reloc_section*
Target_aarch64<size, big_endian>::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_,
ORDER_DYNAMIC_RELOCS, false);
}
return this->rela_dyn_;
}
// A class to handle the PLT data.
// This is an abstract base class that handles most of the linker details
// but does not know the actual contents of PLT entries. The derived
// classes below fill in those details.
template<int size, bool big_endian>
class Output_data_plt_aarch64 : public Output_section_data
{
public:
typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>
Reloc_section;
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
Output_data_plt_aarch64(Layout* layout,
uint64_t addralign,
Output_data_space* got_plt)
: Output_section_data(addralign),
got_plt_(got_plt),
count_(0)
{ this->init(layout); }
// Initialize the PLT section.
void
init(Layout* layout);
// Add an entry to the PLT.
void
add_entry(Symbol* gsym);
// Return the .rela.plt section data.
Reloc_section*
rela_plt()
{ return this->rel_; }
// Return the number of PLT entries.
unsigned int
entry_count() const
{ return this->count_; }
// Return the offset of the first non-reserved PLT entry.
unsigned int
first_plt_entry_offset()
{ return this->do_first_plt_entry_offset(); }
// Return the size of a PLT entry.
unsigned int
get_plt_entry_size() const
{ return this->do_get_plt_entry_size(); }
protected:
// Fill in the first PLT entry.
void
fill_first_plt_entry(unsigned char* pov,
Address got_address,
Address plt_address)
{ this->do_fill_first_plt_entry(pov, got_address, plt_address); }
// Fill in a normal PLT entry.
void
fill_plt_entry(unsigned char* pov,
Address got_address,
Address plt_address,
unsigned int got_offset,
unsigned int plt_offset)
{
this->do_fill_plt_entry(pov, got_address, plt_address,
got_offset, plt_offset);
}
virtual unsigned int
do_first_plt_entry_offset() const = 0;
virtual unsigned int
do_get_plt_entry_size() const = 0;
virtual void
do_fill_first_plt_entry(unsigned char* pov,
Address got_addr,
Address plt_addr) = 0;
virtual void
do_fill_plt_entry(unsigned char* pov,
Address got_address,
Address plt_address,
unsigned int got_offset,
unsigned int plt_offset) = 0;
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:
// 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_aarch64<size, big_endian>* got_;
// The .got.plt section.
Output_data_space* got_plt_;
// The number of PLT entries.
unsigned int count_;
};
// Initialize the PLT section.
template<int size, bool big_endian>
void
Output_data_plt_aarch64<size, big_endian>::init(Layout* layout)
{
this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->rel_,
ORDER_DYNAMIC_PLT_RELOCS, false);
}
template<int size, bool big_endian>
void
Output_data_plt_aarch64<size, big_endian>::do_adjust_output_section(
Output_section* os)
{
os->set_entsize(this->get_plt_entry_size());
}
// Add an entry to the PLT.
template<int size, bool big_endian>
void
Output_data_plt_aarch64<size, big_endian>::add_entry(Symbol* gsym)
{
gold_assert(!gsym->has_plt_offset());
//TODO
}
// Set the final size.
template<int size, bool big_endian>
void
Output_data_plt_aarch64<size, big_endian>::set_final_data_size()
{
this->set_data_size(this->first_plt_entry_offset()
+ this->count * this->get_plt_entry_size());
}
template<int size, bool big_endian>
class Output_data_plt_aarch64_standard :
public Output_data_plt_aarch64<size, big_endian>
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
Output_data_plt_aarch64_standard(Layout* layout, Output_data_space* got_plt)
: Output_data_plt_aarch64<size, big_endian>(layout,
size == 32 ? 4 : 8,
got_plt)
{ }
protected:
// Return the offset of the first non-reserved PLT entry.
virtual unsigned int
do_first_plt_entry_offset() const
{ return this->first_plt_entry_size; }
// Return the size of a PLT entry
virtual unsigned int
do_get_plt_entry_size() const
{ return this->plt_entry_size; }
virtual void
do_fill_first_plt_entry(unsigned char* pov,
Address got_address,
Address plt_address);
virtual void
do_fill_plt_entry(unsigned char* pov,
Address got_address,
Address plt_address,
unsigned int got_offset,
unsigned int plt_offset);
private:
// The size of the first plt entry size.
static const int first_plt_entry_size = 32;
// The size of the plt entry size.
static const int plt_entry_size = 16;
// Template for the first PLT entry.
static const uint32_t first_plt_entry[first_plt_entry_size / 4];
// Template for subsequent PLT entries.
static const uint32_t plt_entry[plt_entry_size / 4];
};
// The first entry in the PLT for an executable.
template<>
const uint32_t
Output_data_plt_aarch64_standard<32, false>::
first_plt_entry[first_plt_entry_size / 4] =
{
0xa9bf7bf0, /* stp x16, x30, [sp, #-16]! */
0x90000010, /* adrp x16, PLT_GOT+0x8 */
0xb9400A11, /* ldr w17, [x16, #PLT_GOT+0x8] */
0x11002210, /* add w16, w16,#PLT_GOT+0x8 */
0xd61f0220, /* br x17 */
0xd503201f, /* nop */
0xd503201f, /* nop */
0xd503201f, /* nop */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<32, true>::
first_plt_entry[first_plt_entry_size / 4] =
{
0xa9bf7bf0, /* stp x16, x30, [sp, #-16]! */
0x90000010, /* adrp x16, PLT_GOT+0x8 */
0xb9400A11, /* ldr w17, [x16, #PLT_GOT+0x8] */
0x11002210, /* add w16, w16,#PLT_GOT+0x8 */
0xd61f0220, /* br x17 */
0xd503201f, /* nop */
0xd503201f, /* nop */
0xd503201f, /* nop */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<64, false>::
first_plt_entry[first_plt_entry_size / 4] =
{
0xa9bf7bf0, /* stp x16, x30, [sp, #-16]! */
0x90000010, /* adrp x16, PLT_GOT+16 */
0xf9400A11, /* ldr x17, [x16, #PLT_GOT+0x10] */
0x91004210, /* add x16, x16,#PLT_GOT+0x10 */
0xd61f0220, /* br x17 */
0xd503201f, /* nop */
0xd503201f, /* nop */
0xd503201f, /* nop */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<64, true>::
first_plt_entry[first_plt_entry_size / 4] =
{
0xa9bf7bf0, /* stp x16, x30, [sp, #-16]! */
0x90000010, /* adrp x16, PLT_GOT+16 */
0xf9400A11, /* ldr x17, [x16, #PLT_GOT+0x10] */
0x91004210, /* add x16, x16,#PLT_GOT+0x10 */
0xd61f0220, /* br x17 */
0xd503201f, /* nop */
0xd503201f, /* nop */
0xd503201f, /* nop */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<32, false>::
plt_entry[plt_entry_size / 4] =
{
0x90000010, /* adrp x16, PLTGOT + n * 4 */
0xb9400211, /* ldr w17, [w16, PLTGOT + n * 4] */
0x11000210, /* add w16, w16, :lo12:PLTGOT + n * 4 */
0xd61f0220, /* br x17. */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<32, true>::
plt_entry[plt_entry_size / 4] =
{
0x90000010, /* adrp x16, PLTGOT + n * 4 */
0xb9400211, /* ldr w17, [w16, PLTGOT + n * 4] */
0x11000210, /* add w16, w16, :lo12:PLTGOT + n * 4 */
0xd61f0220, /* br x17. */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<64, false>::
plt_entry[plt_entry_size / 4] =
{
0x90000010, /* adrp x16, PLTGOT + n * 8 */
0xf9400211, /* ldr x17, [x16, PLTGOT + n * 8] */
0x91000210, /* add x16, x16, :lo12:PLTGOT + n * 8 */
0xd61f0220, /* br x17. */
};
template<>
const uint32_t
Output_data_plt_aarch64_standard<64, true>::
plt_entry[plt_entry_size / 4] =
{
0x90000010, /* adrp x16, PLTGOT + n * 8 */
0xf9400211, /* ldr x17, [x16, PLTGOT + n * 8] */
0x91000210, /* add x16, x16, :lo12:PLTGOT + n * 8 */
0xd61f0220, /* br x17. */
};
template<int size, bool big_endian>
void
Output_data_plt_aarch64_standard<size, big_endian>::do_fill_first_plt_entry(
unsigned char* pov,
Address /* got_address */,
Address /* plt_address */)
{
// PLT0 of the small PLT looks like this in ELF64 -
// stp x16, x30, [sp, #-16]! Save the reloc and lr on stack.
// adrp x16, PLT_GOT + 16 Get the page base of the GOTPLT
// ldr x17, [x16, #:lo12:PLT_GOT+16] Load the address of the
// symbol resolver
// add x16, x16, #:lo12:PLT_GOT+16 Load the lo12 bits of the
// GOTPLT entry for this.
// br x17
// PLT0 will be slightly different in ELF32 due to different got entry
// size.
memcpy(pov, this->first_plt_entry, this->first_plt_entry_size);
// TODO
}
// Subsequent entries in the PLT for an executable.
template<int size, bool big_endian>
void
Output_data_plt_aarch64_standard<size, big_endian>::do_fill_plt_entry(
unsigned char* pov,
Address /* got_address*/,
Address /* plt_address */,
unsigned int /* got_offset */,
unsigned int /* plt_offset */)
{
memcpy(pov, this->plt_entry, this->plt_entry_size);
//TODO
}
// Write out the PLT. This uses the hand-coded instructions above,
// and adjusts them as needed. This is specified by the AMD64 ABI.
template<int size, bool big_endian>
void
Output_data_plt_aarch64<size, big_endian>::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.
typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address();
// The base address of the .got section.
typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address();
// The base address of the PLT portion of the .got section.
typename elfcpp::Elf_types<size>::Elf_Addr got_address
= this->got_plt_->address();
this->fill_first_plt_entry(pov, got_address, plt_address);
pov += this->first_plt_entry_offset();
// The first three entries in .got.plt are reserved.
unsigned char* got_pov = got_view;
memset(got_pov, 0, size / 8 * AARCH64_GOTPLT_RESERVE_COUNT);
got_pov += (size / 8) * AARCH64_GOTPLT_RESERVE_COUNT;
unsigned int plt_offset = this->first_plt_entry_offset();
unsigned int got_offset = (size / 8) * AARCH64_GOTPLT_RESERVE_COUNT;
const unsigned int count = this->count_;
for (unsigned int plt_index = 0;
plt_index < count;
++plt_index,
pov += this->get_plt_entry_size(),
got_pov += size / 8,
plt_offset += this->get_plt_entry_size(),
got_offset += size / 8)
{
// Set and adjust the PLT entry itself.
this->fill_plt_entry(pov, got_address, plt_address,
got_offset, plt_offset);
// Set the entry in the GOT.
elfcpp::Swap<size, big_endian>::writeval(got_pov,
plt_address + plt_offset);
}
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);
}
// Return the number of entries in the PLT.
template<int size, bool big_endian>
unsigned int
Target_aarch64<size, big_endian>::plt_entry_count() const
{
if (this->plt_ == NULL)
return 0;
return this->plt_->entry_count();
}
// Return the offset of the first non-reserved PLT entry.
template<int size, bool big_endian>
unsigned int
Target_aarch64<size, big_endian>::first_plt_entry_offset() const
{
return this->plt_->first_plt_entry_offset();
}
// Return the size of each PLT entry.
template<int size, bool big_endian>
unsigned int
Target_aarch64<size, big_endian>::plt_entry_size() const
{
return this->plt_->get_plt_entry_size();
}
// 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.
template<int size, bool big_endian>
tls::Tls_optimization
Target_aarch64<size, big_endian>::optimize_tls_reloc(bool /* is_final */,
int /* r_type */)
{
//TODO
return tls::TLSOPT_NONE;
}
// Get the Reference_flags for a particular relocation.
template<int size, bool big_endian>
int
Target_aarch64<size, big_endian>::Scan::get_reference_flags(unsigned int r_type)
{
switch (r_type)
{
case elfcpp::R_AARCH64_NONE:
// No symbol reference.
return 0;
//TODO
default:
// Not expected. We will give an error later.
return 0;
}
}
// Returns true if this relocation type could be that of a function pointer.
template<int size, bool big_endian>
inline bool
Target_aarch64<size, big_endian>::Scan::possible_function_pointer_reloc(
unsigned int r_type)
{
switch (r_type)
{
case elfcpp::R_AARCH64_ABS64:
//TODO
{
return true;
}
}
return false;
}
// For safe ICF, scan a relocation for a local symbol to check if it
// corresponds to a function pointer being taken. In that case mark
// the function whose pointer was taken as not foldable.
template<int size, bool big_endian>
inline bool
Target_aarch64<size, big_endian>::Scan::local_reloc_may_be_function_pointer(
Symbol_table* ,
Layout* ,
Target_aarch64<size, big_endian>* ,
Sized_relobj_file<size, big_endian>* ,
unsigned int ,
Output_section* ,
const elfcpp::Rela<size, big_endian>& ,
unsigned int r_type,
const elfcpp::Sym<size, big_endian>&)
{
// When building a shared library, do not fold any local symbols as it is
// not possible to distinguish pointer taken versus a call by looking at
// the relocation types.
return (parameters->options().shared()
|| possible_function_pointer_reloc(r_type));
}
// For safe ICF, scan a relocation for a global symbol to check if it
// corresponds to a function pointer being taken. In that case mark
// the function whose pointer was taken as not foldable.
template<int size, bool big_endian>
inline bool
Target_aarch64<size, big_endian>::Scan::global_reloc_may_be_function_pointer(
Symbol_table* ,
Layout* ,
Target_aarch64<size, big_endian>* ,
Sized_relobj_file<size, big_endian>* ,
unsigned int ,
Output_section* ,
const elfcpp::Rela<size, big_endian>& ,
unsigned int r_type,
Symbol* gsym)
{
// When building a shared library, do not fold symbols whose visibility
// is hidden, internal or protected.
return ((parameters->options().shared()
&& (gsym->visibility() == elfcpp::STV_INTERNAL
|| gsym->visibility() == elfcpp::STV_PROTECTED
|| gsym->visibility() == elfcpp::STV_HIDDEN))
|| possible_function_pointer_reloc(r_type));
}
// Report an unsupported relocation against a local symbol.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::Scan::unsupported_reloc_local(
Sized_relobj_file<size, big_endian>* 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.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::Scan::check_non_pic(Relobj* object,
unsigned int r_type)
{
gold_assert(r_type != elfcpp::R_AARCH64_NONE);
switch (r_type)
{
// These are the relocation types supported by glibc for AARCH64.
case elfcpp::R_AARCH64_NONE:
case elfcpp::R_AARCH64_COPY:
case elfcpp::R_AARCH64_GLOB_DAT:
case elfcpp::R_AARCH64_JUMP_SLOT:
case elfcpp::R_AARCH64_RELATIVE:
case elfcpp::R_AARCH64_TLS_DTPREL64:
case elfcpp::R_AARCH64_TLS_DTPMOD64:
case elfcpp::R_AARCH64_TLS_TPREL64:
case elfcpp::R_AARCH64_TLSDESC:
case elfcpp::R_AARCH64_IRELATIVE:
case elfcpp::R_AARCH64_ABS32:
case elfcpp::R_AARCH64_ABS64:
return;
default:
break;
}
// 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;
}
// Scan a relocation for a local symbol.
template<int size, bool big_endian>
inline void
Target_aarch64<size, big_endian>::Scan::local(
Symbol_table* /* symtab */,
Layout* /* layout */,
Target_aarch64<size, big_endian>* /* target */,
Sized_relobj_file<size, big_endian>* /* object */,
unsigned int /* data_shndx */,
Output_section* /* output_section */,
const elfcpp::Rela<size, big_endian>& /* reloc */,
unsigned int r_type,
const elfcpp::Sym<size, big_endian>& /* lsym */,
bool is_discarded)
{
if (is_discarded)
return;
switch (r_type)
{
case elfcpp::R_AARCH64_NONE:
break;
//TODO
}
}
// Report an unsupported relocation against a global symbol.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::Scan::unsupported_reloc_global(
Sized_relobj_file<size, big_endian>* 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());
}
template<int size, bool big_endian>
inline void
Target_aarch64<size, big_endian>::Scan::global(
Symbol_table* /* symtab */,
Layout* /* layout */,
Target_aarch64<size, big_endian>* /* target */,
Sized_relobj_file<size, big_endian>* /* object */,
unsigned int /* data_shndx */,
Output_section* /* output_section */,
const elfcpp::Rela<size, big_endian>& /* reloc */,
unsigned int /* r_type */,
Symbol* /* gsym */)
{
//TODO
return;
}
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::gc_process_relocs(
Symbol_table* symtab,
Layout* layout,
Sized_relobj_file<size, big_endian>* 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<size, big_endian,
Target_aarch64<size, big_endian>,
elfcpp::SHT_RELA,
typename Target_aarch64<size, big_endian>::Scan,
typename Target_aarch64<size, big_endian>::Relocatable_size_for_reloc>(
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.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::scan_relocs(
Symbol_table* symtab,
Layout* layout,
Sized_relobj_file<size, big_endian>* 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<size, big_endian, Target_aarch64<size, big_endian>,
elfcpp::SHT_RELA,
typename Target_aarch64<size, big_endian>::Scan>(
symtab,
layout,
this,
object,
data_shndx,
prelocs,
reloc_count,
output_section,
needs_special_offset_handling,
local_symbol_count,
plocal_symbols);
}
// Finalize the sections.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::do_finalize_sections(
Layout* /* layout */,
const Input_objects*,
Symbol_table* /* symtab */)
{
//TODO
return;
}
// Perform a relocation.
template<int size, bool big_endian>
inline bool
Target_aarch64<size, big_endian>::Relocate::relocate(
const Relocate_info<size, big_endian>* /* relinfo */,
Target_aarch64<size, big_endian>* /* target */,
Output_section* ,
size_t /* relnum */,
const elfcpp::Rela<size, big_endian>& /* rela */,
unsigned int /* r_type */,
const Sized_symbol<size>* /* gsym */,
const Symbol_value<size>* /* psymval */,
unsigned char* /* view */,
typename elfcpp::Elf_types<size>::Elf_Addr /* address */,
section_size_type /* view_size */)
{
//TODO
return true;
}
// Relocate section data.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::relocate_section(
const Relocate_info<size, big_endian>* /* 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 */,
typename elfcpp::Elf_types<size>::Elf_Addr /* address */,
section_size_type /* view_size */,
const Reloc_symbol_changes* /* reloc_symbol_changes */)
{
//TODO
gold_assert(sh_type == elfcpp::SHT_RELA);
}
// Return the size of a relocation while scanning during a relocatable
// link.
template<int size, bool big_endian>
unsigned int
Target_aarch64<size, big_endian>::Relocatable_size_for_reloc::
get_size_for_reloc(
unsigned int ,
Relobj* )
{
// We will never support SHT_REL relocations.
gold_unreachable();
return 0;
}
// Scan the relocs during a relocatable link.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::scan_relocatable_relocs(
Symbol_table* /* symtab */,
Layout* /* layout */,
Sized_relobj_file<size, big_endian>* /* 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 */)
{
//TODO
gold_assert(sh_type == elfcpp::SHT_RELA);
}
// Relocate a section during a relocatable link.
template<int size, bool big_endian>
void
Target_aarch64<size, big_endian>::relocate_relocs(
const Relocate_info<size, big_endian>* /* relinfo */,
unsigned int sh_type,
const unsigned char* /* prelocs */,
size_t /* reloc_count */,
Output_section* /* output_section */,
typename elfcpp::Elf_types<size>::Elf_Off /* offset_in_output_section */,
const Relocatable_relocs* /* rr */,
unsigned char* /* view */,
typename elfcpp::Elf_types<size>::Elf_Addr /* view_address */,
section_size_type /* view_size */,
unsigned char* /* reloc_view */,
section_size_type /* reloc_view_size */)
{
//TODO
gold_assert(sh_type == elfcpp::SHT_RELA);
}
// The selector for aarch64 object files.
template<int size, bool big_endian>
class Target_selector_aarch64 : public Target_selector
{
public:
Target_selector_aarch64()
: Target_selector(elfcpp::EM_AARCH64, size, big_endian,
(size == 64
? (big_endian ? "elf64-bigaarch64"
: "elf64-littleaarch64")
: (big_endian ? "elf32-bigaarch64"
: "elf32-littleaarch64")),
(size == 64
? (big_endian ? "aarch64_elf64_be_vec"
: "aarch64_elf64_le_vec")
: (big_endian ? "aarch64_elf32_be_vec"
: "aarch64_elf32_le_vec")))
{ }
virtual Target*
do_instantiate_target()
{ return new Target_aarch64<size, big_endian>(); }
};
Target_selector_aarch64<32, true> target_selector_aarch64elf32b;
Target_selector_aarch64<32, false> target_selector_aarch64elf32;
Target_selector_aarch64<64, true> target_selector_aarch64elfb;
Target_selector_aarch64<64, false> target_selector_aarch64elf;
} // End anonymous namespace.
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