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 the size of the GOT section.
120 gold_assert(this->got_
!= NULL
);
121 return this->got_
->data_size();
125 // The class which scans relocations.
129 local(const General_options
& options
, Symbol_table
* symtab
,
130 Layout
* layout
, Target_x86_64
* target
,
131 Sized_relobj
<64, false>* object
,
132 unsigned int data_shndx
,
133 const elfcpp::Rela
<64, false>& reloc
, unsigned int r_type
,
134 const elfcpp::Sym
<64, false>& lsym
);
137 global(const General_options
& options
, Symbol_table
* symtab
,
138 Layout
* layout
, Target_x86_64
* target
,
139 Sized_relobj
<64, false>* object
,
140 unsigned int data_shndx
,
141 const elfcpp::Rela
<64, false>& reloc
, unsigned int r_type
,
145 unsupported_reloc_local(Sized_relobj
<64, false>*, unsigned int r_type
);
148 unsupported_reloc_global(Sized_relobj
<64, false>*, unsigned int r_type
,
152 // The class which implements relocation.
157 : skip_call_tls_get_addr_(false)
162 if (this->skip_call_tls_get_addr_
)
164 // FIXME: This needs to specify the location somehow.
165 gold_error(_("missing expected TLS relocation"));
169 // Do a relocation. Return false if the caller should not issue
170 // any warnings about this relocation.
172 relocate(const Relocate_info
<64, false>*, Target_x86_64
*, size_t relnum
,
173 const elfcpp::Rela
<64, false>&,
174 unsigned int r_type
, const Sized_symbol
<64>*,
175 const Symbol_value
<64>*,
176 unsigned char*, elfcpp::Elf_types
<64>::Elf_Addr
,
180 // Do a TLS relocation.
182 relocate_tls(const Relocate_info
<64, false>*, size_t relnum
,
183 const elfcpp::Rela
<64, false>&,
184 unsigned int r_type
, const Sized_symbol
<64>*,
185 const Symbol_value
<64>*,
186 unsigned char*, elfcpp::Elf_types
<64>::Elf_Addr
, off_t
);
188 // Do a TLS General-Dynamic to Local-Exec transition.
190 tls_gd_to_le(const Relocate_info
<64, false>*, size_t relnum
,
191 Output_segment
* tls_segment
,
192 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
193 elfcpp::Elf_types
<64>::Elf_Addr value
,
197 // Do a TLS Local-Dynamic to Local-Exec transition.
199 tls_ld_to_le(const Relocate_info
<64, false>*, size_t relnum
,
200 Output_segment
* tls_segment
,
201 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
202 elfcpp::Elf_types
<64>::Elf_Addr value
,
206 // Do a TLS Initial-Exec to Local-Exec transition.
208 tls_ie_to_le(const Relocate_info
<64, false>*, size_t relnum
,
209 Output_segment
* tls_segment
,
210 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
211 elfcpp::Elf_types
<64>::Elf_Addr value
,
215 // This is set if we should skip the next reloc, which should be a
216 // PLT32 reloc against ___tls_get_addr.
217 bool skip_call_tls_get_addr_
;
220 // Adjust TLS relocation type based on the options and whether this
221 // is a local symbol.
222 static tls::Tls_optimization
223 optimize_tls_reloc(bool is_final
, int r_type
);
225 // Get the GOT section, creating it if necessary.
226 Output_data_got
<64, false>*
227 got_section(Symbol_table
*, Layout
*);
229 // Get the GOT PLT section.
231 got_plt_section() const
233 gold_assert(this->got_plt_
!= NULL
);
234 return this->got_plt_
;
237 // Create a PLT entry for a global symbol.
239 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
241 // Get the PLT section.
242 Output_data_plt_x86_64
*
245 gold_assert(this->plt_
!= NULL
);
249 // Get the dynamic reloc section, creating it if necessary.
251 rela_dyn_section(Layout
*);
253 // Copy a relocation against a global symbol.
255 copy_reloc(const General_options
*, Symbol_table
*, Layout
*,
256 Sized_relobj
<64, false>*, unsigned int,
257 Symbol
*, const elfcpp::Rela
<64, false>&);
259 // Information about this specific target which we pass to the
260 // general Target structure.
261 static const Target::Target_info x86_64_info
;
264 Output_data_got
<64, false>* got_
;
266 Output_data_plt_x86_64
* plt_
;
267 // The GOT PLT section.
268 Output_data_space
* got_plt_
;
269 // The dynamic reloc section.
270 Reloc_section
* rela_dyn_
;
271 // Relocs saved to avoid a COPY reloc.
272 Copy_relocs
<64, false>* copy_relocs_
;
273 // Space for variables copied with a COPY reloc.
274 Output_data_space
* dynbss_
;
277 const Target::Target_info
Target_x86_64::x86_64_info
=
280 false, // is_big_endian
281 elfcpp::EM_X86_64
, // machine_code
282 false, // has_make_symbol
283 false, // has_resolve
284 true, // has_code_fill
285 true, // is_default_stack_executable
286 "/lib/ld64.so.1", // program interpreter
287 0x400000, // default_text_segment_address
288 0x1000, // abi_pagesize
289 0x1000 // common_pagesize
292 // Get the GOT section, creating it if necessary.
294 Output_data_got
<64, false>*
295 Target_x86_64::got_section(Symbol_table
* symtab
, Layout
* layout
)
297 if (this->got_
== NULL
)
299 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
301 this->got_
= new Output_data_got
<64, false>();
303 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
304 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
307 // The old GNU linker creates a .got.plt section. We just
308 // create another set of data in the .got section. Note that we
309 // always create a PLT if we create a GOT, although the PLT
311 this->got_plt_
= new Output_data_space(8);
312 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
313 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
316 // The first three entries are reserved.
317 this->got_plt_
->set_space_size(3 * 8);
319 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
320 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL
,
322 0, 0, elfcpp::STT_OBJECT
,
324 elfcpp::STV_HIDDEN
, 0,
331 // Get the dynamic reloc section, creating it if necessary.
333 Target_x86_64::Reloc_section
*
334 Target_x86_64::rela_dyn_section(Layout
* layout
)
336 if (this->rela_dyn_
== NULL
)
338 gold_assert(layout
!= NULL
);
339 this->rela_dyn_
= new Reloc_section();
340 layout
->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA
,
341 elfcpp::SHF_ALLOC
, this->rela_dyn_
);
343 return this->rela_dyn_
;
346 // A class to handle the PLT data.
348 class Output_data_plt_x86_64
: public Output_section_data
351 typedef Output_data_reloc
<elfcpp::SHT_RELA
, true, 64, false> Reloc_section
;
353 Output_data_plt_x86_64(Layout
*, Output_data_space
*);
355 // Add an entry to the PLT.
357 add_entry(Symbol
* gsym
);
359 // Return the .rel.plt section data.
362 { return this->rel_
; }
366 do_adjust_output_section(Output_section
* os
);
369 // The size of an entry in the PLT.
370 static const int plt_entry_size
= 16;
372 // The first entry in the PLT.
373 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
374 // procedure linkage table for both programs and shared objects."
375 static unsigned char first_plt_entry
[plt_entry_size
];
377 // Other entries in the PLT for an executable.
378 static unsigned char plt_entry
[plt_entry_size
];
380 // Set the final size.
382 do_set_address(uint64_t, off_t
)
383 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
385 // Write out the PLT data.
387 do_write(Output_file
*);
389 // The reloc section.
391 // The .got.plt section.
392 Output_data_space
* got_plt_
;
393 // The number of PLT entries.
397 // Create the PLT section. The ordinary .got section is an argument,
398 // since we need to refer to the start. We also create our own .got
399 // section just for PLT entries.
401 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout
* layout
,
402 Output_data_space
* got_plt
)
403 : Output_section_data(8), got_plt_(got_plt
), count_(0)
405 this->rel_
= new Reloc_section();
406 layout
->add_output_section_data(".rela.plt", elfcpp::SHT_RELA
,
407 elfcpp::SHF_ALLOC
, this->rel_
);
411 Output_data_plt_x86_64::do_adjust_output_section(Output_section
* os
)
413 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
414 // linker, and so do we.
418 // Add an entry to the PLT.
421 Output_data_plt_x86_64::add_entry(Symbol
* gsym
)
423 gold_assert(!gsym
->has_plt_offset());
425 // Note that when setting the PLT offset we skip the initial
426 // reserved PLT entry.
427 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
431 off_t got_offset
= this->got_plt_
->data_size();
433 // Every PLT entry needs a GOT entry which points back to the PLT
434 // entry (this will be changed by the dynamic linker, normally
435 // lazily when the function is called).
436 this->got_plt_
->set_space_size(got_offset
+ 8);
438 // Every PLT entry needs a reloc.
439 gsym
->set_needs_dynsym_entry();
440 this->rel_
->add_global(gsym
, elfcpp::R_X86_64_JUMP_SLOT
, this->got_plt_
,
443 // Note that we don't need to save the symbol. The contents of the
444 // PLT are independent of which symbols are used. The symbols only
445 // appear in the relocations.
448 // The first entry in the PLT for an executable.
450 unsigned char Output_data_plt_x86_64::first_plt_entry
[plt_entry_size
] =
452 // From AMD64 ABI Draft 0.98, page 76
453 0xff, 0x35, // pushq contents of memory address
454 0, 0, 0, 0, // replaced with address of .got + 4
455 0xff, 0x25, // jmp indirect
456 0, 0, 0, 0, // replaced with address of .got + 8
457 0x90, 0x90, 0x90, 0x90 // noop (x4)
460 // Subsequent entries in the PLT for an executable.
462 unsigned char Output_data_plt_x86_64::plt_entry
[plt_entry_size
] =
464 // From AMD64 ABI Draft 0.98, page 76
465 0xff, 0x25, // jmpq indirect
466 0, 0, 0, 0, // replaced with address of symbol in .got
467 0x68, // pushq immediate
468 0, 0, 0, 0, // replaced with offset into relocation table
469 0xe9, // jmpq relative
470 0, 0, 0, 0 // replaced with offset to start of .plt
473 // Write out the PLT. This uses the hand-coded instructions above,
474 // and adjusts them as needed. This is specified by the AMD64 ABI.
477 Output_data_plt_x86_64::do_write(Output_file
* of
)
479 const off_t offset
= this->offset();
480 const off_t oview_size
= this->data_size();
481 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
483 const off_t got_file_offset
= this->got_plt_
->offset();
484 const off_t got_size
= this->got_plt_
->data_size();
485 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
488 unsigned char* pov
= oview
;
490 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
491 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
493 memcpy(pov
, first_plt_entry
, plt_entry_size
);
494 if (!parameters
->output_is_shared())
496 // We do a jmp relative to the PC at the end of this instruction.
497 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 8
498 - (plt_address
+ 6));
499 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 16
500 - (plt_address
+ 12));
502 pov
+= plt_entry_size
;
504 unsigned char* got_pov
= got_view
;
506 memset(got_pov
, 0, 24);
509 unsigned int plt_offset
= plt_entry_size
;
510 unsigned int got_offset
= 24;
511 const unsigned int count
= this->count_
;
512 for (unsigned int plt_index
= 0;
515 pov
+= plt_entry_size
,
517 plt_offset
+= plt_entry_size
,
520 // Set and adjust the PLT entry itself.
521 memcpy(pov
, plt_entry
, plt_entry_size
);
522 if (parameters
->output_is_shared())
523 // FIXME(csilvers): what's the right thing to write here?
524 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_offset
);
526 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
527 (got_address
+ got_offset
528 - (plt_address
+ plt_offset
531 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_index
);
532 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
533 - (plt_offset
+ plt_entry_size
));
535 // Set the entry in the GOT.
536 elfcpp::Swap
<64, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
539 gold_assert(pov
- oview
== oview_size
);
540 gold_assert(got_pov
- got_view
== got_size
);
542 of
->write_output_view(offset
, oview_size
, oview
);
543 of
->write_output_view(got_file_offset
, got_size
, got_view
);
546 // Create a PLT entry for a global symbol.
549 Target_x86_64::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
552 if (gsym
->has_plt_offset())
555 if (this->plt_
== NULL
)
557 // Create the GOT sections first.
558 this->got_section(symtab
, layout
);
560 this->plt_
= new Output_data_plt_x86_64(layout
, this->got_plt_
);
561 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
563 | elfcpp::SHF_EXECINSTR
),
567 this->plt_
->add_entry(gsym
);
570 // Handle a relocation against a non-function symbol defined in a
571 // dynamic object. The traditional way to handle this is to generate
572 // a COPY relocation to copy the variable at runtime from the shared
573 // object into the executable's data segment. However, this is
574 // undesirable in general, as if the size of the object changes in the
575 // dynamic object, the executable will no longer work correctly. If
576 // this relocation is in a writable section, then we can create a
577 // dynamic reloc and the dynamic linker will resolve it to the correct
578 // address at runtime. However, we do not want do that if the
579 // relocation is in a read-only section, as it would prevent the
580 // readonly segment from being shared. And if we have to eventually
581 // generate a COPY reloc, then any dynamic relocations will be
582 // useless. So this means that if this is a writable section, we need
583 // to save the relocation until we see whether we have to create a
584 // COPY relocation for this symbol for any other relocation.
587 Target_x86_64::copy_reloc(const General_options
* options
,
588 Symbol_table
* symtab
,
590 Sized_relobj
<64, false>* object
,
591 unsigned int data_shndx
, Symbol
* gsym
,
592 const elfcpp::Rela
<64, false>& rela
)
594 Sized_symbol
<64>* ssym
;
595 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(64) (gsym
598 if (!Copy_relocs
<64, false>::need_copy_reloc(options
, object
,
601 // So far we do not need a COPY reloc. Save this relocation.
602 // If it turns out that we never need a COPY reloc for this
603 // symbol, then we will emit the relocation.
604 if (this->copy_relocs_
== NULL
)
605 this->copy_relocs_
= new Copy_relocs
<64, false>();
606 this->copy_relocs_
->save(ssym
, object
, data_shndx
, rela
);
610 // Allocate space for this symbol in the .bss section.
612 elfcpp::Elf_types
<64>::Elf_WXword symsize
= ssym
->symsize();
614 // There is no defined way to determine the required alignment
615 // of the symbol. We pick the alignment based on the size. We
616 // set an arbitrary maximum of 256.
618 for (align
= 1; align
< 512; align
<<= 1)
619 if ((symsize
& align
) != 0)
622 if (this->dynbss_
== NULL
)
624 this->dynbss_
= new Output_data_space(align
);
625 layout
->add_output_section_data(".bss",
628 | elfcpp::SHF_WRITE
),
632 Output_data_space
* dynbss
= this->dynbss_
;
634 if (align
> dynbss
->addralign())
635 dynbss
->set_space_alignment(align
);
637 off_t dynbss_size
= dynbss
->data_size();
638 dynbss_size
= align_address(dynbss_size
, align
);
639 off_t offset
= dynbss_size
;
640 dynbss
->set_space_size(dynbss_size
+ symsize
);
642 symtab
->define_with_copy_reloc(this, ssym
, dynbss
, offset
);
644 // Add the COPY reloc.
645 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
646 rela_dyn
->add_global(ssym
, elfcpp::R_X86_64_COPY
, dynbss
, offset
, 0);
651 // Optimize the TLS relocation type based on what we know about the
652 // symbol. IS_FINAL is true if the final address of this symbol is
653 // known at link time.
655 tls::Tls_optimization
656 Target_x86_64::optimize_tls_reloc(bool is_final
, int r_type
)
658 // If we are generating a shared library, then we can't do anything
660 if (parameters
->output_is_shared())
661 return tls::TLSOPT_NONE
;
665 case elfcpp::R_X86_64_TLSGD
:
666 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
667 case elfcpp::R_X86_64_TLSDESC_CALL
:
668 // These are General-Dynamic which permits fully general TLS
669 // access. Since we know that we are generating an executable,
670 // we can convert this to Initial-Exec. If we also know that
671 // this is a local symbol, we can further switch to Local-Exec.
673 return tls::TLSOPT_TO_LE
;
674 return tls::TLSOPT_TO_IE
;
676 case elfcpp::R_X86_64_TLSLD
:
677 // This is Local-Dynamic, which refers to a local symbol in the
678 // dynamic TLS block. Since we know that we generating an
679 // executable, we can switch to Local-Exec.
680 return tls::TLSOPT_TO_LE
;
682 case elfcpp::R_X86_64_DTPOFF32
:
683 case elfcpp::R_X86_64_DTPOFF64
:
684 // Another Local-Dynamic reloc.
685 return tls::TLSOPT_TO_LE
;
687 case elfcpp::R_X86_64_GOTTPOFF
:
688 // These are Initial-Exec relocs which get the thread offset
689 // from the GOT. If we know that we are linking against the
690 // local symbol, we can switch to Local-Exec, which links the
691 // thread offset into the instruction.
693 return tls::TLSOPT_TO_LE
;
694 return tls::TLSOPT_NONE
;
696 case elfcpp::R_X86_64_TPOFF32
:
697 // When we already have Local-Exec, there is nothing further we
699 return tls::TLSOPT_NONE
;
706 // Report an unsupported relocation against a local symbol.
709 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj
<64, false>* object
,
712 gold_error(_("%s: unsupported reloc %u against local symbol"),
713 object
->name().c_str(), r_type
);
716 // Scan a relocation for a local symbol.
719 Target_x86_64::Scan::local(const General_options
&,
720 Symbol_table
* symtab
,
722 Target_x86_64
* target
,
723 Sized_relobj
<64, false>* object
,
724 unsigned int data_shndx
,
725 const elfcpp::Rela
<64, false>& reloc
,
727 const elfcpp::Sym
<64, false>&)
731 case elfcpp::R_X86_64_NONE
:
732 case elfcpp::R_386_GNU_VTINHERIT
:
733 case elfcpp::R_386_GNU_VTENTRY
:
736 case elfcpp::R_X86_64_64
:
737 case elfcpp::R_X86_64_32
:
738 case elfcpp::R_X86_64_32S
:
739 case elfcpp::R_X86_64_16
:
740 case elfcpp::R_X86_64_8
:
741 // If building a shared library (or a position-independent
742 // executable), we need to create a dynamic relocation for
743 // this location. The relocation applied at link time will
744 // apply the link-time value, so we flag the location with
745 // an R_386_RELATIVE relocation so the dynamic loader can
746 // relocate it easily.
747 if (parameters
->output_is_position_independent())
749 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
750 if (r_type
== elfcpp::R_X86_64_64
)
751 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
752 data_shndx
, reloc
.get_r_offset(), 0);
755 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
756 rela_dyn
->add_local(object
, r_sym
, r_type
, data_shndx
,
757 reloc
.get_r_offset(),
758 reloc
.get_r_addend());
763 case elfcpp::R_X86_64_PC64
:
764 case elfcpp::R_X86_64_PC32
:
765 case elfcpp::R_X86_64_PC16
:
766 case elfcpp::R_X86_64_PC8
:
769 case elfcpp::R_X86_64_PLT32
:
770 // Since we know this is a local symbol, we can handle this as a
774 case elfcpp::R_X86_64_GOTPC32
:
775 case elfcpp::R_X86_64_GOTOFF64
:
776 case elfcpp::R_X86_64_GOTPC64
:
777 case elfcpp::R_X86_64_PLTOFF64
:
778 // We need a GOT section.
779 target
->got_section(symtab
, layout
);
780 // For PLTOFF64, we'd normally want a PLT section, but since we
781 // know this is a local symbol, no PLT is needed.
784 case elfcpp::R_X86_64_GOT64
:
785 case elfcpp::R_X86_64_GOT32
:
786 case elfcpp::R_X86_64_GOTPCREL64
:
787 case elfcpp::R_X86_64_GOTPCREL
:
788 case elfcpp::R_X86_64_GOTPLT64
:
790 // The symbol requires a GOT entry.
791 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
792 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
793 if (got
->add_local(object
, r_sym
))
795 // If we are generating a shared object, we need to add a
796 // dynamic RELATIVE relocation for this symbol.
797 if (parameters
->output_is_position_independent())
799 // FIXME: R_X86_64_RELATIVE assumes a 64-bit relocation.
800 gold_assert(r_type
!= elfcpp::R_X86_64_GOT32
);
802 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
803 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
804 data_shndx
, reloc
.get_r_offset(), 0);
807 // For GOTPLT64, we'd normally want a PLT section, but since
808 // we know this is a local symbol, no PLT is needed.
812 case elfcpp::R_X86_64_COPY
:
813 case elfcpp::R_X86_64_GLOB_DAT
:
814 case elfcpp::R_X86_64_JUMP_SLOT
:
815 case elfcpp::R_X86_64_RELATIVE
:
816 // These are outstanding tls relocs, which are unexpected when linking
817 case elfcpp::R_X86_64_TPOFF64
:
818 case elfcpp::R_X86_64_DTPMOD64
:
819 case elfcpp::R_X86_64_TLSDESC
:
820 gold_error(_("%s: unexpected reloc %u in object file"),
821 object
->name().c_str(), r_type
);
824 // These are initial tls relocs, which are expected when linking
825 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
826 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
827 case elfcpp::R_X86_64_TLSDESC_CALL
:
828 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
829 case elfcpp::R_X86_64_DTPOFF32
:
830 case elfcpp::R_X86_64_DTPOFF64
:
831 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
832 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
834 bool output_is_shared
= parameters
->output_is_shared();
835 const tls::Tls_optimization optimized_type
836 = Target_x86_64::optimize_tls_reloc(!output_is_shared
, r_type
);
839 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
840 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
841 case elfcpp::R_X86_64_TLSDESC_CALL
:
842 // FIXME: If not relaxing to LE, we need to generate
843 // DTPMOD64 and DTPOFF64 relocs.
844 if (optimized_type
!= tls::TLSOPT_TO_LE
)
845 unsupported_reloc_local(object
, r_type
);
848 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
849 case elfcpp::R_X86_64_DTPOFF32
:
850 case elfcpp::R_X86_64_DTPOFF64
:
851 // FIXME: If not relaxing to LE, we need to generate a
853 if (optimized_type
!= tls::TLSOPT_TO_LE
)
854 unsupported_reloc_local(object
, r_type
);
857 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
858 // FIXME: If not relaxing to LE, we need to generate a
860 if (optimized_type
!= tls::TLSOPT_TO_LE
)
861 unsupported_reloc_local(object
, r_type
);
864 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
865 // FIXME: If generating a shared object, we need to copy
866 // this relocation into the object.
867 gold_assert(!output_is_shared
);
876 case elfcpp::R_X86_64_SIZE32
:
877 case elfcpp::R_X86_64_SIZE64
:
879 gold_error(_("%s: unsupported reloc %u against local symbol"),
880 object
->name().c_str(), r_type
);
886 // Report an unsupported relocation against a global symbol.
889 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj
<64, false>* object
,
893 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
894 object
->name().c_str(), r_type
, gsym
->name());
897 // Scan a relocation for a global symbol.
900 Target_x86_64::Scan::global(const General_options
& options
,
901 Symbol_table
* symtab
,
903 Target_x86_64
* target
,
904 Sized_relobj
<64, false>* object
,
905 unsigned int data_shndx
,
906 const elfcpp::Rela
<64, false>& reloc
,
912 case elfcpp::R_X86_64_NONE
:
913 case elfcpp::R_386_GNU_VTINHERIT
:
914 case elfcpp::R_386_GNU_VTENTRY
:
917 case elfcpp::R_X86_64_64
:
918 case elfcpp::R_X86_64_PC64
:
919 case elfcpp::R_X86_64_32
:
920 case elfcpp::R_X86_64_32S
:
921 case elfcpp::R_X86_64_PC32
:
922 case elfcpp::R_X86_64_16
:
923 case elfcpp::R_X86_64_PC16
:
924 case elfcpp::R_X86_64_8
:
925 case elfcpp::R_X86_64_PC8
:
927 bool is_pcrel
= (r_type
== elfcpp::R_X86_64_PC64
928 || r_type
== elfcpp::R_X86_64_PC32
929 || r_type
== elfcpp::R_X86_64_PC16
930 || r_type
== elfcpp::R_X86_64_PC8
);
932 if (gsym
->is_from_dynobj()
933 || (parameters
->output_is_shared()
934 && gsym
->is_preemptible()))
936 // (a) This symbol is defined in a dynamic object. If it is a
937 // function, we make a PLT entry. Otherwise we need to
938 // either generate a COPY reloc or copy this reloc.
939 // (b) We are building a shared object and this symbol is
940 // preemptible. If it is a function, we make a PLT entry.
941 // Otherwise, we copy the reloc.
942 if (gsym
->type() == elfcpp::STT_FUNC
)
944 target
->make_plt_entry(symtab
, layout
, gsym
);
946 // If this is not a PC relative reference, then we may
947 // be taking the address of the function. In that case
948 // we need to set the entry in the dynamic symbol table
949 // to the address of the PLT entry. We will also need to
950 // create a dynamic relocation.
953 if (gsym
->is_from_dynobj())
954 gsym
->set_needs_dynsym_value();
955 if (parameters
->output_is_position_independent())
957 Reloc_section
* rela_dyn
=
958 target
->rela_dyn_section(layout
);
959 rela_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
960 reloc
.get_r_offset(),
961 reloc
.get_r_addend());
965 else if (parameters
->output_is_shared())
967 // We do not make COPY relocs in shared objects.
968 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
969 rela_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
970 reloc
.get_r_offset(),
971 reloc
.get_r_addend());
974 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
977 else if (!is_pcrel
&& parameters
->output_is_position_independent())
979 // This is not a PC-relative reference, so we need to generate
980 // a dynamic relocation. At this point, we know the symbol
981 // is not preemptible, so we can use the RELATIVE relocation.
982 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
983 if (r_type
== elfcpp::R_X86_64_64
)
984 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
986 reloc
.get_r_offset(), 0);
988 rela_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
989 reloc
.get_r_offset(),
990 reloc
.get_r_addend());
995 case elfcpp::R_X86_64_GOT64
:
996 case elfcpp::R_X86_64_GOT32
:
997 case elfcpp::R_X86_64_GOTPCREL64
:
998 case elfcpp::R_X86_64_GOTPCREL
:
999 case elfcpp::R_X86_64_GOTPLT64
:
1001 // The symbol requires a GOT entry.
1002 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
1003 if (got
->add_global(gsym
))
1005 // If this symbol is not fully resolved, we need to add a
1006 // dynamic relocation for it.
1007 if (!gsym
->final_value_is_known())
1009 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1010 rela_dyn
->add_global(gsym
, elfcpp::R_X86_64_GLOB_DAT
, got
,
1011 gsym
->got_offset(), 0);
1014 // For GOTPLT64, we also need a PLT entry (but only if the
1015 // symbol is not fully resolved).
1016 if (r_type
== elfcpp::R_X86_64_GOTPLT64
1017 && !gsym
->final_value_is_known())
1018 target
->make_plt_entry(symtab
, layout
, gsym
);
1022 case elfcpp::R_X86_64_PLT32
:
1023 // If the symbol is fully resolved, this is just a PC32 reloc.
1024 // Otherwise we need a PLT entry.
1025 if (gsym
->final_value_is_known())
1027 // If building a shared library, we can also skip the PLT entry
1028 // if the symbol is defined in the output file and is protected
1030 if (gsym
->is_defined()
1031 && !gsym
->is_from_dynobj()
1032 && !gsym
->is_preemptible())
1034 target
->make_plt_entry(symtab
, layout
, gsym
);
1037 case elfcpp::R_X86_64_GOTPC32
:
1038 case elfcpp::R_X86_64_GOTOFF64
:
1039 case elfcpp::R_X86_64_GOTPC64
:
1040 case elfcpp::R_X86_64_PLTOFF64
:
1041 // We need a GOT section.
1042 target
->got_section(symtab
, layout
);
1043 // For PLTOFF64, we also need a PLT entry (but only if the
1044 // symbol is not fully resolved).
1045 if (r_type
== elfcpp::R_X86_64_PLTOFF64
1046 && !gsym
->final_value_is_known())
1047 target
->make_plt_entry(symtab
, layout
, gsym
);
1050 case elfcpp::R_X86_64_COPY
:
1051 case elfcpp::R_X86_64_GLOB_DAT
:
1052 case elfcpp::R_X86_64_JUMP_SLOT
:
1053 case elfcpp::R_X86_64_RELATIVE
:
1054 // These are outstanding tls relocs, which are unexpected when linking
1055 case elfcpp::R_X86_64_TPOFF64
:
1056 case elfcpp::R_X86_64_DTPMOD64
:
1057 case elfcpp::R_X86_64_TLSDESC
:
1058 gold_error(_("%s: unexpected reloc %u in object file"),
1059 object
->name().c_str(), r_type
);
1062 // These are initial tls relocs, which are expected for global()
1063 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1064 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1065 case elfcpp::R_X86_64_TLSDESC_CALL
:
1066 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1067 case elfcpp::R_X86_64_DTPOFF32
:
1068 case elfcpp::R_X86_64_DTPOFF64
:
1069 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1070 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1072 const bool is_final
= gsym
->final_value_is_known();
1073 const tls::Tls_optimization optimized_type
1074 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
1077 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
1078 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
1079 case elfcpp::R_X86_64_TLSDESC_CALL
:
1080 // FIXME: If not relaxing to LE, we need to generate
1081 // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1082 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1083 unsupported_reloc_global(object
, r_type
, gsym
);
1086 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1087 case elfcpp::R_X86_64_DTPOFF32
:
1088 case elfcpp::R_X86_64_DTPOFF64
:
1089 // FIXME: If not relaxing to LE, we need to generate a
1091 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1092 unsupported_reloc_global(object
, r_type
, gsym
);
1095 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1096 // FIXME: If not relaxing to LE, we need to generate a
1098 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1099 unsupported_reloc_global(object
, r_type
, gsym
);
1102 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1103 // FIXME: If generating a shared object, we need to copy
1104 // this relocation into the object.
1105 gold_assert(is_final
);
1114 case elfcpp::R_X86_64_SIZE32
:
1115 case elfcpp::R_X86_64_SIZE64
:
1117 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1118 object
->name().c_str(), r_type
, gsym
->name());
1123 // Scan relocations for a section.
1126 Target_x86_64::scan_relocs(const General_options
& options
,
1127 Symbol_table
* symtab
,
1129 Sized_relobj
<64, false>* object
,
1130 unsigned int data_shndx
,
1131 unsigned int sh_type
,
1132 const unsigned char* prelocs
,
1134 Output_section
* output_section
,
1135 bool needs_special_offset_handling
,
1136 size_t local_symbol_count
,
1137 const unsigned char* plocal_symbols
)
1139 if (sh_type
== elfcpp::SHT_REL
)
1141 gold_error(_("%s: unsupported REL reloc section"),
1142 object
->name().c_str());
1146 gold::scan_relocs
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
1147 Target_x86_64::Scan
>(
1157 needs_special_offset_handling
,
1162 // Finalize the sections.
1165 Target_x86_64::do_finalize_sections(Layout
* layout
)
1167 // Fill in some more dynamic tags.
1168 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1171 if (this->got_plt_
!= NULL
)
1172 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1174 if (this->plt_
!= NULL
)
1176 const Output_data
* od
= this->plt_
->rel_plt();
1177 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1178 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1179 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_RELA
);
1182 if (this->rela_dyn_
!= NULL
)
1184 const Output_data
* od
= this->rela_dyn_
;
1185 odyn
->add_section_address(elfcpp::DT_RELA
, od
);
1186 odyn
->add_section_size(elfcpp::DT_RELASZ
, od
);
1187 odyn
->add_constant(elfcpp::DT_RELAENT
,
1188 elfcpp::Elf_sizes
<64>::rela_size
);
1191 if (!parameters
->output_is_shared())
1193 // The value of the DT_DEBUG tag is filled in by the dynamic
1194 // linker at run time, and used by the debugger.
1195 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1199 // Emit any relocs we saved in an attempt to avoid generating COPY
1201 if (this->copy_relocs_
== NULL
)
1203 if (this->copy_relocs_
->any_to_emit())
1205 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
1206 this->copy_relocs_
->emit(rela_dyn
);
1208 delete this->copy_relocs_
;
1209 this->copy_relocs_
= NULL
;
1212 // Perform a relocation.
1215 Target_x86_64::Relocate::relocate(const Relocate_info
<64, false>* relinfo
,
1216 Target_x86_64
* target
,
1218 const elfcpp::Rela
<64, false>& rela
,
1219 unsigned int r_type
,
1220 const Sized_symbol
<64>* gsym
,
1221 const Symbol_value
<64>* psymval
,
1222 unsigned char* view
,
1223 elfcpp::Elf_types
<64>::Elf_Addr address
,
1226 if (this->skip_call_tls_get_addr_
)
1228 if (r_type
!= elfcpp::R_X86_64_PLT32
1230 || strcmp(gsym
->name(), "__tls_get_addr") != 0)
1232 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1233 _("missing expected TLS relocation"));
1237 this->skip_call_tls_get_addr_
= false;
1242 // Pick the value to use for symbols defined in shared objects.
1243 Symbol_value
<64> symval
;
1245 && (gsym
->is_from_dynobj()
1246 || (parameters
->output_is_shared()
1247 && gsym
->is_preemptible()))
1248 && gsym
->has_plt_offset())
1250 symval
.set_output_value(target
->plt_section()->address()
1251 + gsym
->plt_offset());
1255 const Sized_relobj
<64, false>* object
= relinfo
->object
;
1256 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
1258 // Get the GOT offset if needed.
1259 // The GOT pointer points to the end of the GOT section.
1260 // We need to subtract the size of the GOT section to get
1261 // the actual offset to use in the relocation.
1262 bool have_got_offset
= false;
1263 unsigned int got_offset
= 0;
1266 case elfcpp::R_X86_64_GOT32
:
1267 case elfcpp::R_X86_64_GOT64
:
1268 case elfcpp::R_X86_64_GOTPLT64
:
1269 case elfcpp::R_X86_64_GOTPCREL
:
1270 case elfcpp::R_X86_64_GOTPCREL64
:
1273 gold_assert(gsym
->has_got_offset());
1274 got_offset
= gsym
->got_offset() - target
->got_size();
1278 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
1279 got_offset
= object
->local_got_offset(r_sym
) - target
->got_size();
1281 have_got_offset
= true;
1290 case elfcpp::R_X86_64_NONE
:
1291 case elfcpp::R_386_GNU_VTINHERIT
:
1292 case elfcpp::R_386_GNU_VTENTRY
:
1295 case elfcpp::R_X86_64_64
:
1296 Relocate_functions
<64, false>::rela64(view
, object
, psymval
, addend
);
1299 case elfcpp::R_X86_64_PC64
:
1300 Relocate_functions
<64, false>::pcrela64(view
, object
, psymval
, addend
,
1304 case elfcpp::R_X86_64_32
:
1305 // FIXME: we need to verify that value + addend fits into 32 bits:
1306 // uint64_t x = value + addend;
1307 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1308 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1309 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
1312 case elfcpp::R_X86_64_32S
:
1313 // FIXME: we need to verify that value + addend fits into 32 bits:
1314 // int64_t x = value + addend; // note this quantity is signed!
1315 // x == static_cast<int64_t>(static_cast<int32_t>(x))
1316 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
1319 case elfcpp::R_X86_64_PC32
:
1320 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
1324 case elfcpp::R_X86_64_16
:
1325 Relocate_functions
<64, false>::rela16(view
, object
, psymval
, addend
);
1328 case elfcpp::R_X86_64_PC16
:
1329 Relocate_functions
<64, false>::pcrela16(view
, object
, psymval
, addend
,
1333 case elfcpp::R_X86_64_8
:
1334 Relocate_functions
<64, false>::rela8(view
, object
, psymval
, addend
);
1337 case elfcpp::R_X86_64_PC8
:
1338 Relocate_functions
<64, false>::pcrela8(view
, object
, psymval
, addend
,
1342 case elfcpp::R_X86_64_PLT32
:
1343 gold_assert(gsym
== NULL
1344 || gsym
->has_plt_offset()
1345 || gsym
->final_value_is_known());
1346 // Note: while this code looks the same as for R_X86_64_PC32, it
1347 // behaves differently because psymval was set to point to
1348 // the PLT entry, rather than the symbol, in Scan::global().
1349 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
1353 case elfcpp::R_X86_64_PLTOFF64
:
1356 gold_assert(gsym
->has_plt_offset()
1357 || gsym
->final_value_is_known());
1358 elfcpp::Elf_types
<64>::Elf_Addr got_address
;
1359 got_address
= target
->got_section(NULL
, NULL
)->address();
1360 Relocate_functions
<64, false>::rela64(view
, object
, psymval
,
1361 addend
- got_address
);
1364 case elfcpp::R_X86_64_GOT32
:
1365 gold_assert(have_got_offset
);
1366 Relocate_functions
<64, false>::rela32(view
, got_offset
, addend
);
1369 case elfcpp::R_X86_64_GOTPC32
:
1372 elfcpp::Elf_types
<64>::Elf_Addr value
;
1373 value
= target
->got_plt_section()->address();
1374 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
1378 case elfcpp::R_X86_64_GOT64
:
1379 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1380 // Since we always add a PLT entry, this is equivalent.
1381 case elfcpp::R_X86_64_GOTPLT64
:
1382 gold_assert(have_got_offset
);
1383 Relocate_functions
<64, false>::rela64(view
, got_offset
, addend
);
1386 case elfcpp::R_X86_64_GOTPC64
:
1389 elfcpp::Elf_types
<64>::Elf_Addr value
;
1390 value
= target
->got_plt_section()->address();
1391 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
1395 case elfcpp::R_X86_64_GOTOFF64
:
1397 elfcpp::Elf_types
<64>::Elf_Addr value
;
1398 value
= (psymval
->value(object
, 0)
1399 - target
->got_plt_section()->address());
1400 Relocate_functions
<64, false>::rela64(view
, value
, addend
);
1404 case elfcpp::R_X86_64_GOTPCREL
:
1406 gold_assert(have_got_offset
);
1407 elfcpp::Elf_types
<64>::Elf_Addr value
;
1408 value
= target
->got_plt_section()->address() + got_offset
;
1409 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
1413 case elfcpp::R_X86_64_GOTPCREL64
:
1415 gold_assert(have_got_offset
);
1416 elfcpp::Elf_types
<64>::Elf_Addr value
;
1417 value
= target
->got_plt_section()->address() + got_offset
;
1418 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
1422 case elfcpp::R_X86_64_COPY
:
1423 case elfcpp::R_X86_64_GLOB_DAT
:
1424 case elfcpp::R_X86_64_JUMP_SLOT
:
1425 case elfcpp::R_X86_64_RELATIVE
:
1426 // These are outstanding tls relocs, which are unexpected when linking
1427 case elfcpp::R_X86_64_TPOFF64
:
1428 case elfcpp::R_X86_64_DTPMOD64
:
1429 case elfcpp::R_X86_64_TLSDESC
:
1430 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1431 _("unexpected reloc %u in object file"),
1435 // These are initial tls relocs, which are expected when linking
1436 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1437 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1438 case elfcpp::R_X86_64_TLSDESC_CALL
:
1439 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1440 case elfcpp::R_X86_64_DTPOFF32
:
1441 case elfcpp::R_X86_64_DTPOFF64
:
1442 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1443 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1444 this->relocate_tls(relinfo
, relnum
, rela
, r_type
, gsym
, psymval
, view
,
1445 address
, view_size
);
1448 case elfcpp::R_X86_64_SIZE32
:
1449 case elfcpp::R_X86_64_SIZE64
:
1451 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1452 _("unsupported reloc %u"),
1460 // Perform a TLS relocation.
1463 Target_x86_64::Relocate::relocate_tls(const Relocate_info
<64, false>* relinfo
,
1465 const elfcpp::Rela
<64, false>& rela
,
1466 unsigned int r_type
,
1467 const Sized_symbol
<64>* gsym
,
1468 const Symbol_value
<64>* psymval
,
1469 unsigned char* view
,
1470 elfcpp::Elf_types
<64>::Elf_Addr
,
1473 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1474 if (tls_segment
== NULL
)
1476 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1477 _("TLS reloc but no TLS segment"));
1481 elfcpp::Elf_types
<64>::Elf_Addr value
= psymval
->value(relinfo
->object
, 0);
1483 const bool is_final
= (gsym
== NULL
1484 ? !parameters
->output_is_position_independent()
1485 : gsym
->final_value_is_known());
1486 const tls::Tls_optimization optimized_type
1487 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
1490 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1491 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1492 case elfcpp::R_X86_64_TLSDESC_CALL
:
1493 if (optimized_type
== tls::TLSOPT_TO_LE
)
1495 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1496 rela
, r_type
, value
, view
,
1500 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1501 _("unsupported reloc %u"), r_type
);
1504 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1505 if (optimized_type
== tls::TLSOPT_TO_LE
)
1507 this->tls_ld_to_le(relinfo
, relnum
, tls_segment
, rela
, r_type
,
1508 value
, view
, view_size
);
1511 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1512 _("unsupported reloc %u"), r_type
);
1515 case elfcpp::R_X86_64_DTPOFF32
:
1516 if (optimized_type
== tls::TLSOPT_TO_LE
)
1517 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1519 value
= value
- tls_segment
->vaddr();
1520 Relocate_functions
<64, false>::rel32(view
, value
);
1523 case elfcpp::R_X86_64_DTPOFF64
:
1524 if (optimized_type
== tls::TLSOPT_TO_LE
)
1525 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1527 value
= value
- tls_segment
->vaddr();
1528 Relocate_functions
<64, false>::rel64(view
, value
);
1531 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1532 if (optimized_type
== tls::TLSOPT_TO_LE
)
1534 Target_x86_64::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1535 rela
, r_type
, value
, view
,
1539 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1540 _("unsupported reloc type %u"),
1544 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1545 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1546 Relocate_functions
<64, false>::rel32(view
, value
);
1551 // Do a relocation in which we convert a TLS General-Dynamic to a
1555 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info
<64, false>* relinfo
,
1557 Output_segment
* tls_segment
,
1558 const elfcpp::Rela
<64, false>& rela
,
1560 elfcpp::Elf_types
<64>::Elf_Addr value
,
1561 unsigned char* view
,
1564 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1565 // .word 0x6666; rex64; call __tls_get_addr
1566 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1568 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -4);
1569 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 12);
1571 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1572 (memcmp(view
- 4, "\x66\x48\x8d\x3d", 4) == 0));
1573 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1574 (memcmp(view
+ 4, "\x66\x66\x48\xe8", 4) == 0));
1576 memcpy(view
- 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1578 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1579 Relocate_functions
<64, false>::rela32(view
+ 8, value
, 0);
1581 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1583 this->skip_call_tls_get_addr_
= true;
1587 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info
<64, false>* relinfo
,
1590 const elfcpp::Rela
<64, false>& rela
,
1592 elfcpp::Elf_types
<64>::Elf_Addr
,
1593 unsigned char* view
,
1596 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1597 // ... leq foo@dtpoff(%rax),%reg
1598 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1600 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
1601 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 9);
1603 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1604 view
[-3] == 0x48 && view
[-2] == 0x8d && view
[-1] == 0x3d);
1606 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(), view
[4] == 0xe8);
1608 memcpy(view
- 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1610 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1612 this->skip_call_tls_get_addr_
= true;
1615 // Do a relocation in which we convert a TLS Initial-Exec to a
1619 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info
<64, false>* relinfo
,
1621 Output_segment
* tls_segment
,
1622 const elfcpp::Rela
<64, false>& rela
,
1624 elfcpp::Elf_types
<64>::Elf_Addr value
,
1625 unsigned char* view
,
1628 // We need to examine the opcodes to figure out which instruction we
1631 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
1632 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
1634 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
1635 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 4);
1637 unsigned char op1
= view
[-3];
1638 unsigned char op2
= view
[-2];
1639 unsigned char op3
= view
[-1];
1640 unsigned char reg
= op3
>> 3;
1648 view
[-1] = 0xc0 | reg
;
1652 // Special handling for %rsp.
1656 view
[-1] = 0xc0 | reg
;
1664 view
[-1] = 0x80 | reg
| (reg
<< 3);
1667 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1668 Relocate_functions
<64, false>::rela32(view
, value
, 0);
1671 // Relocate section data.
1674 Target_x86_64::relocate_section(const Relocate_info
<64, false>* relinfo
,
1675 unsigned int sh_type
,
1676 const unsigned char* prelocs
,
1678 Output_section
* output_section
,
1679 bool needs_special_offset_handling
,
1680 unsigned char* view
,
1681 elfcpp::Elf_types
<64>::Elf_Addr address
,
1684 gold_assert(sh_type
== elfcpp::SHT_RELA
);
1686 gold::relocate_section
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
1687 Target_x86_64::Relocate
>(
1693 needs_special_offset_handling
,
1699 // Return the value to use for a dynamic which requires special
1700 // treatment. This is how we support equality comparisons of function
1701 // pointers across shared library boundaries, as described in the
1702 // processor specific ABI supplement.
1705 Target_x86_64::do_dynsym_value(const Symbol
* gsym
) const
1707 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1708 return this->plt_section()->address() + gsym
->plt_offset();
1711 // Return a string used to fill a code section with nops to take up
1712 // the specified length.
1715 Target_x86_64::do_code_fill(off_t length
)
1719 // Build a jmpq instruction to skip over the bytes.
1720 unsigned char jmp
[5];
1722 elfcpp::Swap_unaligned
<64, false>::writeval(jmp
+ 1, length
- 5);
1723 return (std::string(reinterpret_cast<char*>(&jmp
[0]), 5)
1724 + std::string(length
- 5, '\0'));
1727 // Nop sequences of various lengths.
1728 const char nop1
[1] = { 0x90 }; // nop
1729 const char nop2
[2] = { 0x66, 0x90 }; // xchg %ax %ax
1730 const char nop3
[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1731 const char nop4
[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1732 const char nop5
[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1733 0x00 }; // leal 0(%esi,1),%esi
1734 const char nop6
[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1736 const char nop7
[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1738 const char nop8
[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1739 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1740 const char nop9
[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1741 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1743 const char nop10
[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1744 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1746 const char nop11
[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1747 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1749 const char nop12
[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1750 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1751 0x00, 0x00, 0x00, 0x00 };
1752 const char nop13
[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1753 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1754 0x27, 0x00, 0x00, 0x00,
1756 const char nop14
[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1757 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1758 0xbc, 0x27, 0x00, 0x00,
1760 const char nop15
[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1761 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1762 0x90, 0x90, 0x90, 0x90,
1765 const char* nops
[16] = {
1767 nop1
, nop2
, nop3
, nop4
, nop5
, nop6
, nop7
,
1768 nop8
, nop9
, nop10
, nop11
, nop12
, nop13
, nop14
, nop15
1771 return std::string(nops
[length
], length
);
1774 // The selector for x86_64 object files.
1776 class Target_selector_x86_64
: public Target_selector
1779 Target_selector_x86_64()
1780 : Target_selector(elfcpp::EM_X86_64
, 64, false)
1784 recognize(int machine
, int osabi
, int abiversion
);
1787 Target_x86_64
* target_
;
1790 // Recognize an x86_64 object file when we already know that the machine
1791 // number is EM_X86_64.
1794 Target_selector_x86_64::recognize(int, int, int)
1796 if (this->target_
== NULL
)
1797 this->target_
= new Target_x86_64();
1798 return this->target_
;
1801 Target_selector_x86_64 target_selector_x86_64
;
1803 } // End anonymous namespace.