1 // x86_64.cc -- x86_64 target support for gold.
3 // Copyright 2006, 2007, Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU Library General Public License
10 // as published by the Free Software Foundation; either version 2, or
11 // (at your option) any later version.
13 // In addition to the permissions in the GNU Library General Public
14 // License, the Free Software Foundation gives you unlimited
15 // permission to link the compiled version of this file into
16 // combinations with other programs, and to distribute those
17 // combinations without any restriction coming from the use of this
18 // file. (The Library Public License restrictions do apply in other
19 // respects; for example, they cover modification of the file, and
20 /// distribution when not linked into a combined executable.)
22 // This program is distributed in the hope that it will be useful, but
23 // WITHOUT ANY WARRANTY; without even the implied warranty of
24 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25 // Library General Public License for more details.
27 // You should have received a copy of the GNU Library General Public
28 // License along with this program; if not, write to the Free Software
29 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
37 #include "parameters.h"
45 #include "target-reloc.h"
46 #include "target-select.h"
54 class Output_data_plt_x86_64
;
56 // The x86_64 target class.
58 // http://www.x86-64.org/documentation/abi.pdf
59 // TLS info comes from
60 // http://people.redhat.com/drepper/tls.pdf
61 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
63 class Target_x86_64
: public Sized_target
<64, false>
66 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
67 // uses only Elf64_Rela relocation entries with explicit addends."
68 typedef Output_data_reloc
<elfcpp::SHT_RELA
, true, 64, false> Reloc_section
;
71 : Sized_target
<64, false>(&x86_64_info
),
72 got_(NULL
), plt_(NULL
), got_plt_(NULL
), rela_dyn_(NULL
),
73 copy_relocs_(NULL
), dynbss_(NULL
)
76 // Scan the relocations to look for symbol adjustments.
78 scan_relocs(const General_options
& options
,
81 Sized_relobj
<64, false>* object
,
82 unsigned int data_shndx
,
84 const unsigned char* prelocs
,
86 Output_section
* output_section
,
87 bool needs_special_offset_handling
,
88 size_t local_symbol_count
,
89 const unsigned char* plocal_symbols
);
91 // Finalize the sections.
93 do_finalize_sections(Layout
*);
95 // Return the value to use for a dynamic which requires special
98 do_dynsym_value(const Symbol
*) const;
100 // Relocate a section.
102 relocate_section(const Relocate_info
<64, false>*,
103 unsigned int sh_type
,
104 const unsigned char* prelocs
,
106 Output_section
* output_section
,
107 bool needs_special_offset_handling
,
109 elfcpp::Elf_types
<64>::Elf_Addr view_address
,
112 // Return a string used to fill a code section with nops.
114 do_code_fill(off_t length
);
116 // Return whether SYM is defined by the ABI.
118 do_is_defined_by_abi(Symbol
* sym
) const
119 { return strcmp(sym
->name(), "__tls_get_addr") == 0; }
121 // Return the size of the GOT section.
125 gold_assert(this->got_
!= NULL
);
126 return this->got_
->data_size();
130 // The class which scans relocations.
134 local(const General_options
& options
, Symbol_table
* symtab
,
135 Layout
* layout
, Target_x86_64
* target
,
136 Sized_relobj
<64, false>* object
,
137 unsigned int data_shndx
,
138 Output_section
* output_section
,
139 const elfcpp::Rela
<64, false>& reloc
, unsigned int r_type
,
140 const elfcpp::Sym
<64, false>& lsym
);
143 global(const General_options
& options
, Symbol_table
* symtab
,
144 Layout
* layout
, Target_x86_64
* target
,
145 Sized_relobj
<64, false>* object
,
146 unsigned int data_shndx
,
147 Output_section
* output_section
,
148 const elfcpp::Rela
<64, false>& reloc
, unsigned int r_type
,
152 unsupported_reloc_local(Sized_relobj
<64, false>*, unsigned int r_type
);
155 unsupported_reloc_global(Sized_relobj
<64, false>*, unsigned int r_type
,
159 // The class which implements relocation.
164 : skip_call_tls_get_addr_(false)
169 if (this->skip_call_tls_get_addr_
)
171 // FIXME: This needs to specify the location somehow.
172 gold_error(_("missing expected TLS relocation"));
176 // Do a relocation. Return false if the caller should not issue
177 // any warnings about this relocation.
179 relocate(const Relocate_info
<64, false>*, Target_x86_64
*, size_t relnum
,
180 const elfcpp::Rela
<64, false>&,
181 unsigned int r_type
, const Sized_symbol
<64>*,
182 const Symbol_value
<64>*,
183 unsigned char*, elfcpp::Elf_types
<64>::Elf_Addr
,
187 // Do a TLS relocation.
189 relocate_tls(const Relocate_info
<64, false>*, Target_x86_64
*,
190 size_t relnum
, const elfcpp::Rela
<64, false>&,
191 unsigned int r_type
, const Sized_symbol
<64>*,
192 const Symbol_value
<64>*,
193 unsigned char*, elfcpp::Elf_types
<64>::Elf_Addr
, off_t
);
195 // Do a TLS General-Dynamic to Local-Exec transition.
197 tls_gd_to_ie(const Relocate_info
<64, false>*, size_t relnum
,
198 Output_segment
* tls_segment
,
199 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
200 elfcpp::Elf_types
<64>::Elf_Addr value
,
204 // Do a TLS General-Dynamic to Local-Exec transition.
206 tls_gd_to_le(const Relocate_info
<64, false>*, size_t relnum
,
207 Output_segment
* tls_segment
,
208 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
209 elfcpp::Elf_types
<64>::Elf_Addr value
,
213 // Do a TLS Local-Dynamic to Local-Exec transition.
215 tls_ld_to_le(const Relocate_info
<64, false>*, size_t relnum
,
216 Output_segment
* tls_segment
,
217 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
218 elfcpp::Elf_types
<64>::Elf_Addr value
,
222 // Do a TLS Initial-Exec to Local-Exec transition.
224 tls_ie_to_le(const Relocate_info
<64, false>*, size_t relnum
,
225 Output_segment
* tls_segment
,
226 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
227 elfcpp::Elf_types
<64>::Elf_Addr value
,
231 // This is set if we should skip the next reloc, which should be a
232 // PLT32 reloc against ___tls_get_addr.
233 bool skip_call_tls_get_addr_
;
236 // Adjust TLS relocation type based on the options and whether this
237 // is a local symbol.
238 static tls::Tls_optimization
239 optimize_tls_reloc(bool is_final
, int r_type
);
241 // Get the GOT section, creating it if necessary.
242 Output_data_got
<64, false>*
243 got_section(Symbol_table
*, Layout
*);
245 // Get the GOT PLT section.
247 got_plt_section() const
249 gold_assert(this->got_plt_
!= NULL
);
250 return this->got_plt_
;
253 // Create a PLT entry for a global symbol.
255 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
257 // Get the PLT section.
258 Output_data_plt_x86_64
*
261 gold_assert(this->plt_
!= NULL
);
265 // Get the dynamic reloc section, creating it if necessary.
267 rela_dyn_section(Layout
*);
269 // Return true if the symbol may need a COPY relocation.
270 // References from an executable object to non-function symbols
271 // defined in a dynamic object may need a COPY relocation.
273 may_need_copy_reloc(Symbol
* gsym
)
275 return (!parameters
->output_is_shared()
276 && gsym
->is_from_dynobj()
277 && gsym
->type() != elfcpp::STT_FUNC
);
280 // Copy a relocation against a global symbol.
282 copy_reloc(const General_options
*, Symbol_table
*, Layout
*,
283 Sized_relobj
<64, false>*, unsigned int,
284 Output_section
*, Symbol
*, const elfcpp::Rela
<64, false>&);
286 // Information about this specific target which we pass to the
287 // general Target structure.
288 static const Target::Target_info x86_64_info
;
291 Output_data_got
<64, false>* got_
;
293 Output_data_plt_x86_64
* plt_
;
294 // The GOT PLT section.
295 Output_data_space
* got_plt_
;
296 // The dynamic reloc section.
297 Reloc_section
* rela_dyn_
;
298 // Relocs saved to avoid a COPY reloc.
299 Copy_relocs
<64, false>* copy_relocs_
;
300 // Space for variables copied with a COPY reloc.
301 Output_data_space
* dynbss_
;
304 const Target::Target_info
Target_x86_64::x86_64_info
=
307 false, // is_big_endian
308 elfcpp::EM_X86_64
, // machine_code
309 false, // has_make_symbol
310 false, // has_resolve
311 true, // has_code_fill
312 true, // is_default_stack_executable
313 "/lib/ld64.so.1", // program interpreter
314 0x400000, // default_text_segment_address
315 0x1000, // abi_pagesize
316 0x1000 // common_pagesize
319 // Get the GOT section, creating it if necessary.
321 Output_data_got
<64, false>*
322 Target_x86_64::got_section(Symbol_table
* symtab
, Layout
* layout
)
324 if (this->got_
== NULL
)
326 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
328 this->got_
= new Output_data_got
<64, false>();
330 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
331 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
334 // The old GNU linker creates a .got.plt section. We just
335 // create another set of data in the .got section. Note that we
336 // always create a PLT if we create a GOT, although the PLT
338 this->got_plt_
= new Output_data_space(8);
339 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
340 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
343 // The first three entries are reserved.
344 this->got_plt_
->set_current_data_size(3 * 8);
346 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
347 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL
,
349 0, 0, elfcpp::STT_OBJECT
,
351 elfcpp::STV_HIDDEN
, 0,
358 // Get the dynamic reloc section, creating it if necessary.
360 Target_x86_64::Reloc_section
*
361 Target_x86_64::rela_dyn_section(Layout
* layout
)
363 if (this->rela_dyn_
== NULL
)
365 gold_assert(layout
!= NULL
);
366 this->rela_dyn_
= new Reloc_section();
367 layout
->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA
,
368 elfcpp::SHF_ALLOC
, this->rela_dyn_
);
370 return this->rela_dyn_
;
373 // A class to handle the PLT data.
375 class Output_data_plt_x86_64
: public Output_section_data
378 typedef Output_data_reloc
<elfcpp::SHT_RELA
, true, 64, false> Reloc_section
;
380 Output_data_plt_x86_64(Layout
*, Output_data_space
*);
382 // Add an entry to the PLT.
384 add_entry(Symbol
* gsym
);
386 // Return the .rel.plt section data.
389 { return this->rel_
; }
393 do_adjust_output_section(Output_section
* os
);
396 // The size of an entry in the PLT.
397 static const int plt_entry_size
= 16;
399 // The first entry in the PLT.
400 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
401 // procedure linkage table for both programs and shared objects."
402 static unsigned char first_plt_entry
[plt_entry_size
];
404 // Other entries in the PLT for an executable.
405 static unsigned char plt_entry
[plt_entry_size
];
407 // Set the final size.
409 set_final_data_size()
410 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
412 // Write out the PLT data.
414 do_write(Output_file
*);
416 // The reloc section.
418 // The .got.plt section.
419 Output_data_space
* got_plt_
;
420 // The number of PLT entries.
424 // Create the PLT section. The ordinary .got section is an argument,
425 // since we need to refer to the start. We also create our own .got
426 // section just for PLT entries.
428 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout
* layout
,
429 Output_data_space
* got_plt
)
430 : Output_section_data(8), got_plt_(got_plt
), count_(0)
432 this->rel_
= new Reloc_section();
433 layout
->add_output_section_data(".rela.plt", elfcpp::SHT_RELA
,
434 elfcpp::SHF_ALLOC
, this->rel_
);
438 Output_data_plt_x86_64::do_adjust_output_section(Output_section
* os
)
440 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
441 // linker, and so do we.
445 // Add an entry to the PLT.
448 Output_data_plt_x86_64::add_entry(Symbol
* gsym
)
450 gold_assert(!gsym
->has_plt_offset());
452 // Note that when setting the PLT offset we skip the initial
453 // reserved PLT entry.
454 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
458 off_t got_offset
= this->got_plt_
->current_data_size();
460 // Every PLT entry needs a GOT entry which points back to the PLT
461 // entry (this will be changed by the dynamic linker, normally
462 // lazily when the function is called).
463 this->got_plt_
->set_current_data_size(got_offset
+ 8);
465 // Every PLT entry needs a reloc.
466 gsym
->set_needs_dynsym_entry();
467 this->rel_
->add_global(gsym
, elfcpp::R_X86_64_JUMP_SLOT
, this->got_plt_
,
470 // Note that we don't need to save the symbol. The contents of the
471 // PLT are independent of which symbols are used. The symbols only
472 // appear in the relocations.
475 // The first entry in the PLT for an executable.
477 unsigned char Output_data_plt_x86_64::first_plt_entry
[plt_entry_size
] =
479 // From AMD64 ABI Draft 0.98, page 76
480 0xff, 0x35, // pushq contents of memory address
481 0, 0, 0, 0, // replaced with address of .got + 8
482 0xff, 0x25, // jmp indirect
483 0, 0, 0, 0, // replaced with address of .got + 16
484 0x90, 0x90, 0x90, 0x90 // noop (x4)
487 // Subsequent entries in the PLT for an executable.
489 unsigned char Output_data_plt_x86_64::plt_entry
[plt_entry_size
] =
491 // From AMD64 ABI Draft 0.98, page 76
492 0xff, 0x25, // jmpq indirect
493 0, 0, 0, 0, // replaced with address of symbol in .got
494 0x68, // pushq immediate
495 0, 0, 0, 0, // replaced with offset into relocation table
496 0xe9, // jmpq relative
497 0, 0, 0, 0 // replaced with offset to start of .plt
500 // Write out the PLT. This uses the hand-coded instructions above,
501 // and adjusts them as needed. This is specified by the AMD64 ABI.
504 Output_data_plt_x86_64::do_write(Output_file
* of
)
506 const off_t offset
= this->offset();
507 const off_t oview_size
= this->data_size();
508 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
510 const off_t got_file_offset
= this->got_plt_
->offset();
511 const off_t got_size
= this->got_plt_
->data_size();
512 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
515 unsigned char* pov
= oview
;
517 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
518 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
520 memcpy(pov
, first_plt_entry
, plt_entry_size
);
521 // We do a jmp relative to the PC at the end of this instruction.
522 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 8
523 - (plt_address
+ 6));
524 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 16
525 - (plt_address
+ 12));
526 pov
+= plt_entry_size
;
528 unsigned char* got_pov
= got_view
;
530 memset(got_pov
, 0, 24);
533 unsigned int plt_offset
= plt_entry_size
;
534 unsigned int got_offset
= 24;
535 const unsigned int count
= this->count_
;
536 for (unsigned int plt_index
= 0;
539 pov
+= plt_entry_size
,
541 plt_offset
+= plt_entry_size
,
544 // Set and adjust the PLT entry itself.
545 memcpy(pov
, plt_entry
, plt_entry_size
);
546 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
547 (got_address
+ got_offset
548 - (plt_address
+ plt_offset
551 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_index
);
552 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
553 - (plt_offset
+ plt_entry_size
));
555 // Set the entry in the GOT.
556 elfcpp::Swap
<64, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
559 gold_assert(pov
- oview
== oview_size
);
560 gold_assert(got_pov
- got_view
== got_size
);
562 of
->write_output_view(offset
, oview_size
, oview
);
563 of
->write_output_view(got_file_offset
, got_size
, got_view
);
566 // Create a PLT entry for a global symbol.
569 Target_x86_64::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
572 if (gsym
->has_plt_offset())
575 if (this->plt_
== NULL
)
577 // Create the GOT sections first.
578 this->got_section(symtab
, layout
);
580 this->plt_
= new Output_data_plt_x86_64(layout
, this->got_plt_
);
581 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
583 | elfcpp::SHF_EXECINSTR
),
587 this->plt_
->add_entry(gsym
);
590 // Handle a relocation against a non-function symbol defined in a
591 // dynamic object. The traditional way to handle this is to generate
592 // a COPY relocation to copy the variable at runtime from the shared
593 // object into the executable's data segment. However, this is
594 // undesirable in general, as if the size of the object changes in the
595 // dynamic object, the executable will no longer work correctly. If
596 // this relocation is in a writable section, then we can create a
597 // dynamic reloc and the dynamic linker will resolve it to the correct
598 // address at runtime. However, we do not want do that if the
599 // relocation is in a read-only section, as it would prevent the
600 // readonly segment from being shared. And if we have to eventually
601 // generate a COPY reloc, then any dynamic relocations will be
602 // useless. So this means that if this is a writable section, we need
603 // to save the relocation until we see whether we have to create a
604 // COPY relocation for this symbol for any other relocation.
607 Target_x86_64::copy_reloc(const General_options
* options
,
608 Symbol_table
* symtab
,
610 Sized_relobj
<64, false>* object
,
611 unsigned int data_shndx
,
612 Output_section
* output_section
,
614 const elfcpp::Rela
<64, false>& rela
)
616 Sized_symbol
<64>* ssym
;
617 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(64) (gsym
620 if (!Copy_relocs
<64, false>::need_copy_reloc(options
, object
,
623 // So far we do not need a COPY reloc. Save this relocation.
624 // If it turns out that we never need a COPY reloc for this
625 // symbol, then we will emit the relocation.
626 if (this->copy_relocs_
== NULL
)
627 this->copy_relocs_
= new Copy_relocs
<64, false>();
628 this->copy_relocs_
->save(ssym
, object
, data_shndx
, output_section
, rela
);
632 // Allocate space for this symbol in the .bss section.
634 elfcpp::Elf_types
<64>::Elf_WXword symsize
= ssym
->symsize();
636 // There is no defined way to determine the required alignment
637 // of the symbol. We pick the alignment based on the size. We
638 // set an arbitrary maximum of 256.
640 for (align
= 1; align
< 512; align
<<= 1)
641 if ((symsize
& align
) != 0)
644 if (this->dynbss_
== NULL
)
646 this->dynbss_
= new Output_data_space(align
);
647 layout
->add_output_section_data(".bss",
650 | elfcpp::SHF_WRITE
),
654 Output_data_space
* dynbss
= this->dynbss_
;
656 if (align
> dynbss
->addralign())
657 dynbss
->set_space_alignment(align
);
659 off_t dynbss_size
= dynbss
->current_data_size();
660 dynbss_size
= align_address(dynbss_size
, align
);
661 off_t offset
= dynbss_size
;
662 dynbss
->set_current_data_size(dynbss_size
+ symsize
);
664 symtab
->define_with_copy_reloc(this, ssym
, dynbss
, offset
);
666 // Add the COPY reloc.
667 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
668 rela_dyn
->add_global(ssym
, elfcpp::R_X86_64_COPY
, dynbss
, offset
, 0);
673 // Optimize the TLS relocation type based on what we know about the
674 // symbol. IS_FINAL is true if the final address of this symbol is
675 // known at link time.
677 tls::Tls_optimization
678 Target_x86_64::optimize_tls_reloc(bool is_final
, int r_type
)
680 // If we are generating a shared library, then we can't do anything
682 if (parameters
->output_is_shared())
683 return tls::TLSOPT_NONE
;
687 case elfcpp::R_X86_64_TLSGD
:
688 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
689 case elfcpp::R_X86_64_TLSDESC_CALL
:
690 // These are General-Dynamic which permits fully general TLS
691 // access. Since we know that we are generating an executable,
692 // we can convert this to Initial-Exec. If we also know that
693 // this is a local symbol, we can further switch to Local-Exec.
695 return tls::TLSOPT_TO_LE
;
696 return tls::TLSOPT_TO_IE
;
698 case elfcpp::R_X86_64_TLSLD
:
699 // This is Local-Dynamic, which refers to a local symbol in the
700 // dynamic TLS block. Since we know that we generating an
701 // executable, we can switch to Local-Exec.
702 return tls::TLSOPT_TO_LE
;
704 case elfcpp::R_X86_64_DTPOFF32
:
705 case elfcpp::R_X86_64_DTPOFF64
:
706 // Another Local-Dynamic reloc.
707 return tls::TLSOPT_TO_LE
;
709 case elfcpp::R_X86_64_GOTTPOFF
:
710 // These are Initial-Exec relocs which get the thread offset
711 // from the GOT. If we know that we are linking against the
712 // local symbol, we can switch to Local-Exec, which links the
713 // thread offset into the instruction.
715 return tls::TLSOPT_TO_LE
;
716 return tls::TLSOPT_NONE
;
718 case elfcpp::R_X86_64_TPOFF32
:
719 // When we already have Local-Exec, there is nothing further we
721 return tls::TLSOPT_NONE
;
728 // Report an unsupported relocation against a local symbol.
731 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj
<64, false>* object
,
734 gold_error(_("%s: unsupported reloc %u against local symbol"),
735 object
->name().c_str(), r_type
);
738 // Scan a relocation for a local symbol.
741 Target_x86_64::Scan::local(const General_options
&,
742 Symbol_table
* symtab
,
744 Target_x86_64
* target
,
745 Sized_relobj
<64, false>* object
,
746 unsigned int data_shndx
,
747 Output_section
* output_section
,
748 const elfcpp::Rela
<64, false>& reloc
,
750 const elfcpp::Sym
<64, false>& lsym
)
754 case elfcpp::R_X86_64_NONE
:
755 case elfcpp::R_386_GNU_VTINHERIT
:
756 case elfcpp::R_386_GNU_VTENTRY
:
759 case elfcpp::R_X86_64_64
:
760 // If building a shared library (or a position-independent
761 // executable), we need to create a dynamic relocation for
762 // this location. The relocation applied at link time will
763 // apply the link-time value, so we flag the location with
764 // an R_386_RELATIVE relocation so the dynamic loader can
765 // relocate it easily.
766 if (parameters
->output_is_position_independent())
768 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
769 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
770 rela_dyn
->add_local_relative(object
, r_sym
,
771 elfcpp::R_X86_64_RELATIVE
,
772 output_section
, data_shndx
,
773 reloc
.get_r_offset(),
774 reloc
.get_r_addend());
778 case elfcpp::R_X86_64_32
:
779 case elfcpp::R_X86_64_32S
:
780 case elfcpp::R_X86_64_16
:
781 case elfcpp::R_X86_64_8
:
782 // If building a shared library (or a position-independent
783 // executable), we need to create a dynamic relocation for
784 // this location. The relocation applied at link time will
785 // apply the link-time value, so we flag the location with
786 // an R_386_RELATIVE relocation so the dynamic loader can
787 // relocate it easily.
788 if (parameters
->output_is_position_independent())
790 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
791 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
792 rela_dyn
->add_local(object
, r_sym
, r_type
, output_section
,
793 data_shndx
, reloc
.get_r_offset(),
794 reloc
.get_r_addend());
798 case elfcpp::R_X86_64_PC64
:
799 case elfcpp::R_X86_64_PC32
:
800 case elfcpp::R_X86_64_PC16
:
801 case elfcpp::R_X86_64_PC8
:
804 case elfcpp::R_X86_64_PLT32
:
805 // Since we know this is a local symbol, we can handle this as a
809 case elfcpp::R_X86_64_GOTPC32
:
810 case elfcpp::R_X86_64_GOTOFF64
:
811 case elfcpp::R_X86_64_GOTPC64
:
812 case elfcpp::R_X86_64_PLTOFF64
:
813 // We need a GOT section.
814 target
->got_section(symtab
, layout
);
815 // For PLTOFF64, we'd normally want a PLT section, but since we
816 // know this is a local symbol, no PLT is needed.
819 case elfcpp::R_X86_64_GOT64
:
820 case elfcpp::R_X86_64_GOT32
:
821 case elfcpp::R_X86_64_GOTPCREL64
:
822 case elfcpp::R_X86_64_GOTPCREL
:
823 case elfcpp::R_X86_64_GOTPLT64
:
825 // The symbol requires a GOT entry.
826 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
827 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
828 if (got
->add_local(object
, r_sym
))
830 // If we are generating a shared object, we need to add a
831 // dynamic relocation for this symbol's GOT entry.
832 if (parameters
->output_is_position_independent())
834 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
835 // R_X86_64_RELATIVE assumes a 64-bit relocation.
836 if (r_type
!= elfcpp::R_X86_64_GOT32
)
837 rela_dyn
->add_local_relative(object
, r_sym
,
838 elfcpp::R_X86_64_RELATIVE
, got
,
839 object
->local_got_offset(r_sym
),
842 rela_dyn
->add_local(object
, r_sym
, r_type
,
843 got
, object
->local_got_offset(r_sym
), 0);
846 // For GOTPLT64, we'd normally want a PLT section, but since
847 // we know this is a local symbol, no PLT is needed.
851 case elfcpp::R_X86_64_COPY
:
852 case elfcpp::R_X86_64_GLOB_DAT
:
853 case elfcpp::R_X86_64_JUMP_SLOT
:
854 case elfcpp::R_X86_64_RELATIVE
:
855 // These are outstanding tls relocs, which are unexpected when linking
856 case elfcpp::R_X86_64_TPOFF64
:
857 case elfcpp::R_X86_64_DTPMOD64
:
858 case elfcpp::R_X86_64_TLSDESC
:
859 gold_error(_("%s: unexpected reloc %u in object file"),
860 object
->name().c_str(), r_type
);
863 // These are initial tls relocs, which are expected when linking
864 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
865 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
866 case elfcpp::R_X86_64_TLSDESC_CALL
:
867 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
868 case elfcpp::R_X86_64_DTPOFF32
:
869 case elfcpp::R_X86_64_DTPOFF64
:
870 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
871 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
873 bool output_is_shared
= parameters
->output_is_shared();
874 const tls::Tls_optimization optimized_type
875 = Target_x86_64::optimize_tls_reloc(!output_is_shared
, r_type
);
878 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
879 if (optimized_type
== tls::TLSOPT_NONE
)
881 // Create a pair of GOT entries for the module index and
882 // dtv-relative offset.
883 Output_data_got
<64, false>* got
884 = target
->got_section(symtab
, layout
);
885 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
886 got
->add_local_tls_with_rela(object
, r_sym
,
887 lsym
.get_st_shndx(), true,
888 target
->rela_dyn_section(layout
),
889 elfcpp::R_X86_64_DTPMOD64
);
891 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
892 unsupported_reloc_local(object
, r_type
);
895 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
896 case elfcpp::R_X86_64_TLSDESC_CALL
:
897 // FIXME: If not relaxing to LE, we need to generate
898 // a GOT entry with a R_x86_64_TLSDESC reloc.
899 if (optimized_type
!= tls::TLSOPT_TO_LE
)
900 unsupported_reloc_local(object
, r_type
);
903 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
904 if (optimized_type
== tls::TLSOPT_NONE
)
906 // Create a GOT entry for the module index.
907 Output_data_got
<64, false>* got
908 = target
->got_section(symtab
, layout
);
909 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
910 got
->add_local_tls_with_rela(object
, r_sym
,
911 lsym
.get_st_shndx(), false,
912 target
->rela_dyn_section(layout
),
913 elfcpp::R_X86_64_DTPMOD64
);
915 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
916 unsupported_reloc_local(object
, r_type
);
919 case elfcpp::R_X86_64_DTPOFF32
:
920 case elfcpp::R_X86_64_DTPOFF64
:
923 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
924 if (optimized_type
== tls::TLSOPT_NONE
)
926 // Create a GOT entry for the tp-relative offset.
927 Output_data_got
<64, false>* got
928 = target
->got_section(symtab
, layout
);
929 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
930 got
->add_local_with_rela(object
, r_sym
,
931 target
->rela_dyn_section(layout
),
932 elfcpp::R_X86_64_TPOFF64
);
934 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
935 unsupported_reloc_local(object
, r_type
);
938 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
939 if (output_is_shared
)
940 unsupported_reloc_local(object
, r_type
);
949 case elfcpp::R_X86_64_SIZE32
:
950 case elfcpp::R_X86_64_SIZE64
:
952 gold_error(_("%s: unsupported reloc %u against local symbol"),
953 object
->name().c_str(), r_type
);
959 // Report an unsupported relocation against a global symbol.
962 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj
<64, false>* object
,
966 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
967 object
->name().c_str(), r_type
, gsym
->demangled_name().c_str());
970 // Scan a relocation for a global symbol.
973 Target_x86_64::Scan::global(const General_options
& options
,
974 Symbol_table
* symtab
,
976 Target_x86_64
* target
,
977 Sized_relobj
<64, false>* object
,
978 unsigned int data_shndx
,
979 Output_section
* output_section
,
980 const elfcpp::Rela
<64, false>& reloc
,
986 case elfcpp::R_X86_64_NONE
:
987 case elfcpp::R_386_GNU_VTINHERIT
:
988 case elfcpp::R_386_GNU_VTENTRY
:
991 case elfcpp::R_X86_64_64
:
992 case elfcpp::R_X86_64_32
:
993 case elfcpp::R_X86_64_32S
:
994 case elfcpp::R_X86_64_16
:
995 case elfcpp::R_X86_64_8
:
997 // Make a PLT entry if necessary.
998 if (gsym
->needs_plt_entry())
1000 target
->make_plt_entry(symtab
, layout
, gsym
);
1001 // Since this is not a PC-relative relocation, we may be
1002 // taking the address of a function. In that case we need to
1003 // set the entry in the dynamic symbol table to the address of
1005 if (gsym
->is_from_dynobj())
1006 gsym
->set_needs_dynsym_value();
1008 // Make a dynamic relocation if necessary.
1009 if (gsym
->needs_dynamic_reloc(true, false))
1011 if (target
->may_need_copy_reloc(gsym
))
1013 target
->copy_reloc(&options
, symtab
, layout
, object
,
1014 data_shndx
, output_section
, gsym
, reloc
);
1016 else if (r_type
== elfcpp::R_X86_64_64
1017 && gsym
->can_use_relative_reloc(false))
1019 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1020 rela_dyn
->add_global_relative(gsym
, elfcpp::R_X86_64_RELATIVE
,
1021 output_section
, object
,
1022 data_shndx
, reloc
.get_r_offset(),
1023 reloc
.get_r_addend());
1027 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1028 rela_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1029 data_shndx
, reloc
.get_r_offset(),
1030 reloc
.get_r_addend());
1036 case elfcpp::R_X86_64_PC64
:
1037 case elfcpp::R_X86_64_PC32
:
1038 case elfcpp::R_X86_64_PC16
:
1039 case elfcpp::R_X86_64_PC8
:
1041 // Make a PLT entry if necessary.
1042 if (gsym
->needs_plt_entry())
1043 target
->make_plt_entry(symtab
, layout
, gsym
);
1044 // Make a dynamic relocation if necessary.
1045 bool is_function_call
= (gsym
->type() == elfcpp::STT_FUNC
);
1046 if (gsym
->needs_dynamic_reloc(false, is_function_call
))
1048 if (target
->may_need_copy_reloc(gsym
))
1050 target
->copy_reloc(&options
, symtab
, layout
, object
,
1051 data_shndx
, output_section
, gsym
, reloc
);
1055 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1056 rela_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1057 data_shndx
, reloc
.get_r_offset(),
1058 reloc
.get_r_addend());
1064 case elfcpp::R_X86_64_GOT64
:
1065 case elfcpp::R_X86_64_GOT32
:
1066 case elfcpp::R_X86_64_GOTPCREL64
:
1067 case elfcpp::R_X86_64_GOTPCREL
:
1068 case elfcpp::R_X86_64_GOTPLT64
:
1070 // The symbol requires a GOT entry.
1071 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
1072 if (gsym
->final_value_is_known())
1073 got
->add_global(gsym
);
1076 // If this symbol is not fully resolved, we need to add a
1077 // dynamic relocation for it.
1078 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1079 if (gsym
->is_from_dynobj() || gsym
->is_preemptible())
1080 got
->add_global_with_rela(gsym
, rela_dyn
,
1081 elfcpp::R_X86_64_GLOB_DAT
);
1084 if (got
->add_global(gsym
))
1085 rela_dyn
->add_global_relative(gsym
,
1086 elfcpp::R_X86_64_RELATIVE
,
1087 got
, gsym
->got_offset(), 0);
1090 // For GOTPLT64, we also need a PLT entry (but only if the
1091 // symbol is not fully resolved).
1092 if (r_type
== elfcpp::R_X86_64_GOTPLT64
1093 && !gsym
->final_value_is_known())
1094 target
->make_plt_entry(symtab
, layout
, gsym
);
1098 case elfcpp::R_X86_64_PLT32
:
1099 // If the symbol is fully resolved, this is just a PC32 reloc.
1100 // Otherwise we need a PLT entry.
1101 if (gsym
->final_value_is_known())
1103 // If building a shared library, we can also skip the PLT entry
1104 // if the symbol is defined in the output file and is protected
1106 if (gsym
->is_defined()
1107 && !gsym
->is_from_dynobj()
1108 && !gsym
->is_preemptible())
1110 target
->make_plt_entry(symtab
, layout
, gsym
);
1113 case elfcpp::R_X86_64_GOTPC32
:
1114 case elfcpp::R_X86_64_GOTOFF64
:
1115 case elfcpp::R_X86_64_GOTPC64
:
1116 case elfcpp::R_X86_64_PLTOFF64
:
1117 // We need a GOT section.
1118 target
->got_section(symtab
, layout
);
1119 // For PLTOFF64, we also need a PLT entry (but only if the
1120 // symbol is not fully resolved).
1121 if (r_type
== elfcpp::R_X86_64_PLTOFF64
1122 && !gsym
->final_value_is_known())
1123 target
->make_plt_entry(symtab
, layout
, gsym
);
1126 case elfcpp::R_X86_64_COPY
:
1127 case elfcpp::R_X86_64_GLOB_DAT
:
1128 case elfcpp::R_X86_64_JUMP_SLOT
:
1129 case elfcpp::R_X86_64_RELATIVE
:
1130 // These are outstanding tls relocs, which are unexpected when linking
1131 case elfcpp::R_X86_64_TPOFF64
:
1132 case elfcpp::R_X86_64_DTPMOD64
:
1133 case elfcpp::R_X86_64_TLSDESC
:
1134 gold_error(_("%s: unexpected reloc %u in object file"),
1135 object
->name().c_str(), r_type
);
1138 // These are initial tls relocs, which are expected for global()
1139 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1140 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1141 case elfcpp::R_X86_64_TLSDESC_CALL
:
1142 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1143 case elfcpp::R_X86_64_DTPOFF32
:
1144 case elfcpp::R_X86_64_DTPOFF64
:
1145 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1146 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1148 const bool is_final
= gsym
->final_value_is_known();
1149 const tls::Tls_optimization optimized_type
1150 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
1153 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
1154 if (optimized_type
== tls::TLSOPT_NONE
)
1156 // Create a pair of GOT entries for the module index and
1157 // dtv-relative offset.
1158 Output_data_got
<64, false>* got
1159 = target
->got_section(symtab
, layout
);
1160 got
->add_global_tls_with_rela(gsym
,
1161 target
->rela_dyn_section(layout
),
1162 elfcpp::R_X86_64_DTPMOD64
,
1163 elfcpp::R_X86_64_DTPOFF64
);
1165 else if (optimized_type
== tls::TLSOPT_TO_IE
)
1167 // Create a GOT entry for the tp-relative offset.
1168 Output_data_got
<64, false>* got
1169 = target
->got_section(symtab
, layout
);
1170 got
->add_global_with_rela(gsym
,
1171 target
->rela_dyn_section(layout
),
1172 elfcpp::R_X86_64_TPOFF64
);
1174 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1175 unsupported_reloc_global(object
, r_type
, gsym
);
1178 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
1179 case elfcpp::R_X86_64_TLSDESC_CALL
:
1180 // FIXME: If not relaxing to LE, we need to generate
1181 // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1182 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1183 unsupported_reloc_global(object
, r_type
, gsym
);
1186 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1187 if (optimized_type
== tls::TLSOPT_NONE
)
1189 // Create a GOT entry for the module index.
1190 Output_data_got
<64, false>* got
1191 = target
->got_section(symtab
, layout
);
1192 got
->add_global_tls_with_rela(gsym
,
1193 target
->rela_dyn_section(layout
),
1194 elfcpp::R_X86_64_DTPMOD64
);
1196 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1197 unsupported_reloc_global(object
, r_type
, gsym
);
1200 case elfcpp::R_X86_64_DTPOFF32
:
1201 case elfcpp::R_X86_64_DTPOFF64
:
1204 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1205 if (optimized_type
== tls::TLSOPT_NONE
)
1207 // Create a GOT entry for the tp-relative offset.
1208 Output_data_got
<64, false>* got
1209 = target
->got_section(symtab
, layout
);
1210 got
->add_global_with_rela(gsym
,
1211 target
->rela_dyn_section(layout
),
1212 elfcpp::R_X86_64_TPOFF64
);
1214 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1215 unsupported_reloc_global(object
, r_type
, gsym
);
1218 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1219 if (parameters
->output_is_shared())
1220 unsupported_reloc_local(object
, r_type
);
1229 case elfcpp::R_X86_64_SIZE32
:
1230 case elfcpp::R_X86_64_SIZE64
:
1232 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1233 object
->name().c_str(), r_type
,
1234 gsym
->demangled_name().c_str());
1239 // Scan relocations for a section.
1242 Target_x86_64::scan_relocs(const General_options
& options
,
1243 Symbol_table
* symtab
,
1245 Sized_relobj
<64, false>* object
,
1246 unsigned int data_shndx
,
1247 unsigned int sh_type
,
1248 const unsigned char* prelocs
,
1250 Output_section
* output_section
,
1251 bool needs_special_offset_handling
,
1252 size_t local_symbol_count
,
1253 const unsigned char* plocal_symbols
)
1255 if (sh_type
== elfcpp::SHT_REL
)
1257 gold_error(_("%s: unsupported REL reloc section"),
1258 object
->name().c_str());
1262 gold::scan_relocs
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
1263 Target_x86_64::Scan
>(
1273 needs_special_offset_handling
,
1278 // Finalize the sections.
1281 Target_x86_64::do_finalize_sections(Layout
* layout
)
1283 // Fill in some more dynamic tags.
1284 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1287 if (this->got_plt_
!= NULL
)
1288 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1290 if (this->plt_
!= NULL
)
1292 const Output_data
* od
= this->plt_
->rel_plt();
1293 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1294 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1295 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_RELA
);
1298 if (this->rela_dyn_
!= NULL
)
1300 const Output_data
* od
= this->rela_dyn_
;
1301 odyn
->add_section_address(elfcpp::DT_RELA
, od
);
1302 odyn
->add_section_size(elfcpp::DT_RELASZ
, od
);
1303 odyn
->add_constant(elfcpp::DT_RELAENT
,
1304 elfcpp::Elf_sizes
<64>::rela_size
);
1307 if (!parameters
->output_is_shared())
1309 // The value of the DT_DEBUG tag is filled in by the dynamic
1310 // linker at run time, and used by the debugger.
1311 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1315 // Emit any relocs we saved in an attempt to avoid generating COPY
1317 if (this->copy_relocs_
== NULL
)
1319 if (this->copy_relocs_
->any_to_emit())
1321 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
1322 this->copy_relocs_
->emit(rela_dyn
);
1324 delete this->copy_relocs_
;
1325 this->copy_relocs_
= NULL
;
1328 // Perform a relocation.
1331 Target_x86_64::Relocate::relocate(const Relocate_info
<64, false>* relinfo
,
1332 Target_x86_64
* target
,
1334 const elfcpp::Rela
<64, false>& rela
,
1335 unsigned int r_type
,
1336 const Sized_symbol
<64>* gsym
,
1337 const Symbol_value
<64>* psymval
,
1338 unsigned char* view
,
1339 elfcpp::Elf_types
<64>::Elf_Addr address
,
1342 if (this->skip_call_tls_get_addr_
)
1344 if (r_type
!= elfcpp::R_X86_64_PLT32
1346 || strcmp(gsym
->name(), "__tls_get_addr") != 0)
1348 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1349 _("missing expected TLS relocation"));
1353 this->skip_call_tls_get_addr_
= false;
1358 // Pick the value to use for symbols defined in shared objects.
1359 Symbol_value
<64> symval
;
1361 && (gsym
->is_from_dynobj()
1362 || (parameters
->output_is_shared()
1363 && gsym
->is_preemptible()))
1364 && gsym
->has_plt_offset())
1366 symval
.set_output_value(target
->plt_section()->address()
1367 + gsym
->plt_offset());
1371 const Sized_relobj
<64, false>* object
= relinfo
->object
;
1372 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
1374 // Get the GOT offset if needed.
1375 // The GOT pointer points to the end of the GOT section.
1376 // We need to subtract the size of the GOT section to get
1377 // the actual offset to use in the relocation.
1378 bool have_got_offset
= false;
1379 unsigned int got_offset
= 0;
1382 case elfcpp::R_X86_64_GOT32
:
1383 case elfcpp::R_X86_64_GOT64
:
1384 case elfcpp::R_X86_64_GOTPLT64
:
1385 case elfcpp::R_X86_64_GOTPCREL
:
1386 case elfcpp::R_X86_64_GOTPCREL64
:
1389 gold_assert(gsym
->has_got_offset());
1390 got_offset
= gsym
->got_offset() - target
->got_size();
1394 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
1395 gold_assert(object
->local_has_got_offset(r_sym
));
1396 got_offset
= object
->local_got_offset(r_sym
) - target
->got_size();
1398 have_got_offset
= true;
1407 case elfcpp::R_X86_64_NONE
:
1408 case elfcpp::R_386_GNU_VTINHERIT
:
1409 case elfcpp::R_386_GNU_VTENTRY
:
1412 case elfcpp::R_X86_64_64
:
1413 Relocate_functions
<64, false>::rela64(view
, object
, psymval
, addend
);
1416 case elfcpp::R_X86_64_PC64
:
1417 Relocate_functions
<64, false>::pcrela64(view
, object
, psymval
, addend
,
1421 case elfcpp::R_X86_64_32
:
1422 // FIXME: we need to verify that value + addend fits into 32 bits:
1423 // uint64_t x = value + addend;
1424 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1425 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1426 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
1429 case elfcpp::R_X86_64_32S
:
1430 // FIXME: we need to verify that value + addend fits into 32 bits:
1431 // int64_t x = value + addend; // note this quantity is signed!
1432 // x == static_cast<int64_t>(static_cast<int32_t>(x))
1433 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
1436 case elfcpp::R_X86_64_PC32
:
1437 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
1441 case elfcpp::R_X86_64_16
:
1442 Relocate_functions
<64, false>::rela16(view
, object
, psymval
, addend
);
1445 case elfcpp::R_X86_64_PC16
:
1446 Relocate_functions
<64, false>::pcrela16(view
, object
, psymval
, addend
,
1450 case elfcpp::R_X86_64_8
:
1451 Relocate_functions
<64, false>::rela8(view
, object
, psymval
, addend
);
1454 case elfcpp::R_X86_64_PC8
:
1455 Relocate_functions
<64, false>::pcrela8(view
, object
, psymval
, addend
,
1459 case elfcpp::R_X86_64_PLT32
:
1460 gold_assert(gsym
== NULL
1461 || gsym
->has_plt_offset()
1462 || gsym
->final_value_is_known());
1463 // Note: while this code looks the same as for R_X86_64_PC32, it
1464 // behaves differently because psymval was set to point to
1465 // the PLT entry, rather than the symbol, in Scan::global().
1466 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
1470 case elfcpp::R_X86_64_PLTOFF64
:
1473 gold_assert(gsym
->has_plt_offset()
1474 || gsym
->final_value_is_known());
1475 elfcpp::Elf_types
<64>::Elf_Addr got_address
;
1476 got_address
= target
->got_section(NULL
, NULL
)->address();
1477 Relocate_functions
<64, false>::rela64(view
, object
, psymval
,
1478 addend
- got_address
);
1481 case elfcpp::R_X86_64_GOT32
:
1482 gold_assert(have_got_offset
);
1483 Relocate_functions
<64, false>::rela32(view
, got_offset
, addend
);
1486 case elfcpp::R_X86_64_GOTPC32
:
1489 elfcpp::Elf_types
<64>::Elf_Addr value
;
1490 value
= target
->got_plt_section()->address();
1491 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
1495 case elfcpp::R_X86_64_GOT64
:
1496 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1497 // Since we always add a PLT entry, this is equivalent.
1498 case elfcpp::R_X86_64_GOTPLT64
:
1499 gold_assert(have_got_offset
);
1500 Relocate_functions
<64, false>::rela64(view
, got_offset
, addend
);
1503 case elfcpp::R_X86_64_GOTPC64
:
1506 elfcpp::Elf_types
<64>::Elf_Addr value
;
1507 value
= target
->got_plt_section()->address();
1508 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
1512 case elfcpp::R_X86_64_GOTOFF64
:
1514 elfcpp::Elf_types
<64>::Elf_Addr value
;
1515 value
= (psymval
->value(object
, 0)
1516 - target
->got_plt_section()->address());
1517 Relocate_functions
<64, false>::rela64(view
, value
, addend
);
1521 case elfcpp::R_X86_64_GOTPCREL
:
1523 gold_assert(have_got_offset
);
1524 elfcpp::Elf_types
<64>::Elf_Addr value
;
1525 value
= target
->got_plt_section()->address() + got_offset
;
1526 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
1530 case elfcpp::R_X86_64_GOTPCREL64
:
1532 gold_assert(have_got_offset
);
1533 elfcpp::Elf_types
<64>::Elf_Addr value
;
1534 value
= target
->got_plt_section()->address() + got_offset
;
1535 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
1539 case elfcpp::R_X86_64_COPY
:
1540 case elfcpp::R_X86_64_GLOB_DAT
:
1541 case elfcpp::R_X86_64_JUMP_SLOT
:
1542 case elfcpp::R_X86_64_RELATIVE
:
1543 // These are outstanding tls relocs, which are unexpected when linking
1544 case elfcpp::R_X86_64_TPOFF64
:
1545 case elfcpp::R_X86_64_DTPMOD64
:
1546 case elfcpp::R_X86_64_TLSDESC
:
1547 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1548 _("unexpected reloc %u in object file"),
1552 // These are initial tls relocs, which are expected when linking
1553 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1554 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1555 case elfcpp::R_X86_64_TLSDESC_CALL
:
1556 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1557 case elfcpp::R_X86_64_DTPOFF32
:
1558 case elfcpp::R_X86_64_DTPOFF64
:
1559 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1560 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1561 this->relocate_tls(relinfo
, target
, relnum
, rela
, r_type
, gsym
, psymval
,
1562 view
, address
, view_size
);
1565 case elfcpp::R_X86_64_SIZE32
:
1566 case elfcpp::R_X86_64_SIZE64
:
1568 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1569 _("unsupported reloc %u"),
1577 // Perform a TLS relocation.
1580 Target_x86_64::Relocate::relocate_tls(const Relocate_info
<64, false>* relinfo
,
1581 Target_x86_64
* target
,
1583 const elfcpp::Rela
<64, false>& rela
,
1584 unsigned int r_type
,
1585 const Sized_symbol
<64>* gsym
,
1586 const Symbol_value
<64>* psymval
,
1587 unsigned char* view
,
1588 elfcpp::Elf_types
<64>::Elf_Addr
,
1591 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1593 const Sized_relobj
<64, false>* object
= relinfo
->object
;
1595 elfcpp::Elf_types
<64>::Elf_Addr value
= psymval
->value(relinfo
->object
, 0);
1597 const bool is_final
= (gsym
== NULL
1598 ? !parameters
->output_is_position_independent()
1599 : gsym
->final_value_is_known());
1600 const tls::Tls_optimization optimized_type
1601 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
1604 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1605 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1606 case elfcpp::R_X86_64_TLSDESC_CALL
:
1607 if (optimized_type
== tls::TLSOPT_TO_LE
)
1609 gold_assert(tls_segment
!= NULL
);
1610 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1611 rela
, r_type
, value
, view
,
1617 unsigned int got_offset
;
1620 gold_assert(gsym
->has_tls_got_offset(true));
1621 got_offset
= gsym
->tls_got_offset(true) - target
->got_size();
1625 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
1626 gold_assert(object
->local_has_tls_got_offset(r_sym
, true));
1627 got_offset
= (object
->local_tls_got_offset(r_sym
, true)
1628 - target
->got_size());
1630 if (optimized_type
== tls::TLSOPT_TO_IE
)
1632 gold_assert(tls_segment
!= NULL
);
1633 this->tls_gd_to_ie(relinfo
, relnum
, tls_segment
, rela
, r_type
,
1634 got_offset
, view
, view_size
);
1637 else if (optimized_type
== tls::TLSOPT_NONE
)
1639 // Relocate the field with the offset of the pair of GOT
1641 Relocate_functions
<64, false>::rel64(view
, got_offset
);
1645 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1646 _("unsupported reloc %u"), r_type
);
1649 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1650 if (optimized_type
== tls::TLSOPT_TO_LE
)
1652 gold_assert(tls_segment
!= NULL
);
1653 this->tls_ld_to_le(relinfo
, relnum
, tls_segment
, rela
, r_type
,
1654 value
, view
, view_size
);
1657 else if (optimized_type
== tls::TLSOPT_NONE
)
1659 // Relocate the field with the offset of the GOT entry for
1660 // the module index.
1661 unsigned int got_offset
;
1664 gold_assert(gsym
->has_tls_got_offset(false));
1665 got_offset
= gsym
->tls_got_offset(false) - target
->got_size();
1669 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
1670 gold_assert(object
->local_has_tls_got_offset(r_sym
, false));
1671 got_offset
= (object
->local_tls_got_offset(r_sym
, false)
1672 - target
->got_size());
1674 Relocate_functions
<64, false>::rel64(view
, got_offset
);
1677 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1678 _("unsupported reloc %u"), r_type
);
1681 case elfcpp::R_X86_64_DTPOFF32
:
1682 gold_assert(tls_segment
!= NULL
);
1683 if (optimized_type
== tls::TLSOPT_TO_LE
)
1684 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1686 value
= value
- tls_segment
->vaddr();
1687 Relocate_functions
<64, false>::rel32(view
, value
);
1690 case elfcpp::R_X86_64_DTPOFF64
:
1691 gold_assert(tls_segment
!= NULL
);
1692 if (optimized_type
== tls::TLSOPT_TO_LE
)
1693 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1695 value
= value
- tls_segment
->vaddr();
1696 Relocate_functions
<64, false>::rel64(view
, value
);
1699 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1700 if (optimized_type
== tls::TLSOPT_TO_LE
)
1702 gold_assert(tls_segment
!= NULL
);
1703 Target_x86_64::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1704 rela
, r_type
, value
, view
,
1708 else if (optimized_type
== tls::TLSOPT_NONE
)
1710 // Relocate the field with the offset of the GOT entry for
1711 // the tp-relative offset of the symbol.
1712 unsigned int got_offset
;
1715 gold_assert(gsym
->has_got_offset());
1716 got_offset
= gsym
->got_offset() - target
->got_size();
1720 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
1721 gold_assert(object
->local_has_got_offset(r_sym
));
1722 got_offset
= (object
->local_got_offset(r_sym
)
1723 - target
->got_size());
1725 Relocate_functions
<64, false>::rel64(view
, got_offset
);
1728 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1729 _("unsupported reloc type %u"),
1733 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1734 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1735 Relocate_functions
<64, false>::rel32(view
, value
);
1740 // Do a relocation in which we convert a TLS General-Dynamic to an
1744 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info
<64, false>* relinfo
,
1746 Output_segment
* tls_segment
,
1747 const elfcpp::Rela
<64, false>& rela
,
1749 elfcpp::Elf_types
<64>::Elf_Addr value
,
1750 unsigned char* view
,
1753 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1754 // .word 0x6666; rex64; call __tls_get_addr
1755 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
1757 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -4);
1758 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 12);
1760 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1761 (memcmp(view
- 4, "\x66\x48\x8d\x3d", 4) == 0));
1762 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1763 (memcmp(view
+ 4, "\x66\x66\x48\xe8", 4) == 0));
1765 memcpy(view
- 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
1767 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1768 Relocate_functions
<64, false>::rela32(view
+ 8, value
, 0);
1770 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1772 this->skip_call_tls_get_addr_
= true;
1775 // Do a relocation in which we convert a TLS General-Dynamic to a
1779 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info
<64, false>* relinfo
,
1781 Output_segment
* tls_segment
,
1782 const elfcpp::Rela
<64, false>& rela
,
1784 elfcpp::Elf_types
<64>::Elf_Addr value
,
1785 unsigned char* view
,
1788 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1789 // .word 0x6666; rex64; call __tls_get_addr
1790 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1792 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -4);
1793 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 12);
1795 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1796 (memcmp(view
- 4, "\x66\x48\x8d\x3d", 4) == 0));
1797 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1798 (memcmp(view
+ 4, "\x66\x66\x48\xe8", 4) == 0));
1800 memcpy(view
- 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1802 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1803 Relocate_functions
<64, false>::rela32(view
+ 8, value
, 0);
1805 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1807 this->skip_call_tls_get_addr_
= true;
1811 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info
<64, false>* relinfo
,
1814 const elfcpp::Rela
<64, false>& rela
,
1816 elfcpp::Elf_types
<64>::Elf_Addr
,
1817 unsigned char* view
,
1820 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1821 // ... leq foo@dtpoff(%rax),%reg
1822 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1824 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
1825 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 9);
1827 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1828 view
[-3] == 0x48 && view
[-2] == 0x8d && view
[-1] == 0x3d);
1830 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(), view
[4] == 0xe8);
1832 memcpy(view
- 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1834 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1836 this->skip_call_tls_get_addr_
= true;
1839 // Do a relocation in which we convert a TLS Initial-Exec to a
1843 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info
<64, false>* relinfo
,
1845 Output_segment
* tls_segment
,
1846 const elfcpp::Rela
<64, false>& rela
,
1848 elfcpp::Elf_types
<64>::Elf_Addr value
,
1849 unsigned char* view
,
1852 // We need to examine the opcodes to figure out which instruction we
1855 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
1856 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
1858 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
1859 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 4);
1861 unsigned char op1
= view
[-3];
1862 unsigned char op2
= view
[-2];
1863 unsigned char op3
= view
[-1];
1864 unsigned char reg
= op3
>> 3;
1872 view
[-1] = 0xc0 | reg
;
1876 // Special handling for %rsp.
1880 view
[-1] = 0xc0 | reg
;
1888 view
[-1] = 0x80 | reg
| (reg
<< 3);
1891 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1892 Relocate_functions
<64, false>::rela32(view
, value
, 0);
1895 // Relocate section data.
1898 Target_x86_64::relocate_section(const Relocate_info
<64, false>* relinfo
,
1899 unsigned int sh_type
,
1900 const unsigned char* prelocs
,
1902 Output_section
* output_section
,
1903 bool needs_special_offset_handling
,
1904 unsigned char* view
,
1905 elfcpp::Elf_types
<64>::Elf_Addr address
,
1908 gold_assert(sh_type
== elfcpp::SHT_RELA
);
1910 gold::relocate_section
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
1911 Target_x86_64::Relocate
>(
1917 needs_special_offset_handling
,
1923 // Return the value to use for a dynamic which requires special
1924 // treatment. This is how we support equality comparisons of function
1925 // pointers across shared library boundaries, as described in the
1926 // processor specific ABI supplement.
1929 Target_x86_64::do_dynsym_value(const Symbol
* gsym
) const
1931 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1932 return this->plt_section()->address() + gsym
->plt_offset();
1935 // Return a string used to fill a code section with nops to take up
1936 // the specified length.
1939 Target_x86_64::do_code_fill(off_t length
)
1943 // Build a jmpq instruction to skip over the bytes.
1944 unsigned char jmp
[5];
1946 elfcpp::Swap_unaligned
<64, false>::writeval(jmp
+ 1, length
- 5);
1947 return (std::string(reinterpret_cast<char*>(&jmp
[0]), 5)
1948 + std::string(length
- 5, '\0'));
1951 // Nop sequences of various lengths.
1952 const char nop1
[1] = { 0x90 }; // nop
1953 const char nop2
[2] = { 0x66, 0x90 }; // xchg %ax %ax
1954 const char nop3
[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1955 const char nop4
[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1956 const char nop5
[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1957 0x00 }; // leal 0(%esi,1),%esi
1958 const char nop6
[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1960 const char nop7
[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1962 const char nop8
[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1963 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1964 const char nop9
[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1965 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1967 const char nop10
[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1968 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1970 const char nop11
[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1971 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1973 const char nop12
[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1974 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1975 0x00, 0x00, 0x00, 0x00 };
1976 const char nop13
[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1977 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1978 0x27, 0x00, 0x00, 0x00,
1980 const char nop14
[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1981 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1982 0xbc, 0x27, 0x00, 0x00,
1984 const char nop15
[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1985 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1986 0x90, 0x90, 0x90, 0x90,
1989 const char* nops
[16] = {
1991 nop1
, nop2
, nop3
, nop4
, nop5
, nop6
, nop7
,
1992 nop8
, nop9
, nop10
, nop11
, nop12
, nop13
, nop14
, nop15
1995 return std::string(nops
[length
], length
);
1998 // The selector for x86_64 object files.
2000 class Target_selector_x86_64
: public Target_selector
2003 Target_selector_x86_64()
2004 : Target_selector(elfcpp::EM_X86_64
, 64, false)
2008 recognize(int machine
, int osabi
, int abiversion
);
2011 Target_x86_64
* target_
;
2014 // Recognize an x86_64 object file when we already know that the machine
2015 // number is EM_X86_64.
2018 Target_selector_x86_64::recognize(int, int, int)
2020 if (this->target_
== NULL
)
2021 this->target_
= new Target_x86_64();
2022 return this->target_
;
2025 Target_selector_x86_64 target_selector_x86_64
;
2027 } // End anonymous namespace.