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 // Return true if the symbol may need a COPY relocation.
254 // References from an executable object to non-function symbols
255 // defined in a dynamic object may need a COPY relocation.
257 may_need_copy_reloc(Symbol
* gsym
)
259 return (!parameters
->output_is_shared()
260 && gsym
->is_from_dynobj()
261 && gsym
->type() != elfcpp::STT_FUNC
);
264 // Copy a relocation against a global symbol.
266 copy_reloc(const General_options
*, Symbol_table
*, Layout
*,
267 Sized_relobj
<64, false>*, unsigned int,
268 Symbol
*, const elfcpp::Rela
<64, false>&);
270 // Information about this specific target which we pass to the
271 // general Target structure.
272 static const Target::Target_info x86_64_info
;
275 Output_data_got
<64, false>* got_
;
277 Output_data_plt_x86_64
* plt_
;
278 // The GOT PLT section.
279 Output_data_space
* got_plt_
;
280 // The dynamic reloc section.
281 Reloc_section
* rela_dyn_
;
282 // Relocs saved to avoid a COPY reloc.
283 Copy_relocs
<64, false>* copy_relocs_
;
284 // Space for variables copied with a COPY reloc.
285 Output_data_space
* dynbss_
;
288 const Target::Target_info
Target_x86_64::x86_64_info
=
291 false, // is_big_endian
292 elfcpp::EM_X86_64
, // machine_code
293 false, // has_make_symbol
294 false, // has_resolve
295 true, // has_code_fill
296 true, // is_default_stack_executable
297 "/lib/ld64.so.1", // program interpreter
298 0x400000, // default_text_segment_address
299 0x1000, // abi_pagesize
300 0x1000 // common_pagesize
303 // Get the GOT section, creating it if necessary.
305 Output_data_got
<64, false>*
306 Target_x86_64::got_section(Symbol_table
* symtab
, Layout
* layout
)
308 if (this->got_
== NULL
)
310 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
312 this->got_
= new Output_data_got
<64, false>();
314 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
315 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
318 // The old GNU linker creates a .got.plt section. We just
319 // create another set of data in the .got section. Note that we
320 // always create a PLT if we create a GOT, although the PLT
322 this->got_plt_
= new Output_data_space(8);
323 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
324 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
327 // The first three entries are reserved.
328 this->got_plt_
->set_space_size(3 * 8);
330 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
331 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL
,
333 0, 0, elfcpp::STT_OBJECT
,
335 elfcpp::STV_HIDDEN
, 0,
342 // Get the dynamic reloc section, creating it if necessary.
344 Target_x86_64::Reloc_section
*
345 Target_x86_64::rela_dyn_section(Layout
* layout
)
347 if (this->rela_dyn_
== NULL
)
349 gold_assert(layout
!= NULL
);
350 this->rela_dyn_
= new Reloc_section();
351 layout
->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA
,
352 elfcpp::SHF_ALLOC
, this->rela_dyn_
);
354 return this->rela_dyn_
;
357 // A class to handle the PLT data.
359 class Output_data_plt_x86_64
: public Output_section_data
362 typedef Output_data_reloc
<elfcpp::SHT_RELA
, true, 64, false> Reloc_section
;
364 Output_data_plt_x86_64(Layout
*, Output_data_space
*);
366 // Add an entry to the PLT.
368 add_entry(Symbol
* gsym
);
370 // Return the .rel.plt section data.
373 { return this->rel_
; }
377 do_adjust_output_section(Output_section
* os
);
380 // The size of an entry in the PLT.
381 static const int plt_entry_size
= 16;
383 // The first entry in the PLT.
384 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
385 // procedure linkage table for both programs and shared objects."
386 static unsigned char first_plt_entry
[plt_entry_size
];
388 // Other entries in the PLT for an executable.
389 static unsigned char plt_entry
[plt_entry_size
];
391 // Set the final size.
393 do_set_address(uint64_t, off_t
)
394 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
396 // Write out the PLT data.
398 do_write(Output_file
*);
400 // The reloc section.
402 // The .got.plt section.
403 Output_data_space
* got_plt_
;
404 // The number of PLT entries.
408 // Create the PLT section. The ordinary .got section is an argument,
409 // since we need to refer to the start. We also create our own .got
410 // section just for PLT entries.
412 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout
* layout
,
413 Output_data_space
* got_plt
)
414 : Output_section_data(8), got_plt_(got_plt
), count_(0)
416 this->rel_
= new Reloc_section();
417 layout
->add_output_section_data(".rela.plt", elfcpp::SHT_RELA
,
418 elfcpp::SHF_ALLOC
, this->rel_
);
422 Output_data_plt_x86_64::do_adjust_output_section(Output_section
* os
)
424 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
425 // linker, and so do we.
429 // Add an entry to the PLT.
432 Output_data_plt_x86_64::add_entry(Symbol
* gsym
)
434 gold_assert(!gsym
->has_plt_offset());
436 // Note that when setting the PLT offset we skip the initial
437 // reserved PLT entry.
438 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
442 off_t got_offset
= this->got_plt_
->data_size();
444 // Every PLT entry needs a GOT entry which points back to the PLT
445 // entry (this will be changed by the dynamic linker, normally
446 // lazily when the function is called).
447 this->got_plt_
->set_space_size(got_offset
+ 8);
449 // Every PLT entry needs a reloc.
450 gsym
->set_needs_dynsym_entry();
451 this->rel_
->add_global(gsym
, elfcpp::R_X86_64_JUMP_SLOT
, this->got_plt_
,
454 // Note that we don't need to save the symbol. The contents of the
455 // PLT are independent of which symbols are used. The symbols only
456 // appear in the relocations.
459 // The first entry in the PLT for an executable.
461 unsigned char Output_data_plt_x86_64::first_plt_entry
[plt_entry_size
] =
463 // From AMD64 ABI Draft 0.98, page 76
464 0xff, 0x35, // pushq contents of memory address
465 0, 0, 0, 0, // replaced with address of .got + 4
466 0xff, 0x25, // jmp indirect
467 0, 0, 0, 0, // replaced with address of .got + 8
468 0x90, 0x90, 0x90, 0x90 // noop (x4)
471 // Subsequent entries in the PLT for an executable.
473 unsigned char Output_data_plt_x86_64::plt_entry
[plt_entry_size
] =
475 // From AMD64 ABI Draft 0.98, page 76
476 0xff, 0x25, // jmpq indirect
477 0, 0, 0, 0, // replaced with address of symbol in .got
478 0x68, // pushq immediate
479 0, 0, 0, 0, // replaced with offset into relocation table
480 0xe9, // jmpq relative
481 0, 0, 0, 0 // replaced with offset to start of .plt
484 // Write out the PLT. This uses the hand-coded instructions above,
485 // and adjusts them as needed. This is specified by the AMD64 ABI.
488 Output_data_plt_x86_64::do_write(Output_file
* of
)
490 const off_t offset
= this->offset();
491 const off_t oview_size
= this->data_size();
492 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
494 const off_t got_file_offset
= this->got_plt_
->offset();
495 const off_t got_size
= this->got_plt_
->data_size();
496 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
499 unsigned char* pov
= oview
;
501 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
502 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
504 memcpy(pov
, first_plt_entry
, plt_entry_size
);
505 if (!parameters
->output_is_shared())
507 // We do a jmp relative to the PC at the end of this instruction.
508 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 8
509 - (plt_address
+ 6));
510 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 16
511 - (plt_address
+ 12));
513 pov
+= plt_entry_size
;
515 unsigned char* got_pov
= got_view
;
517 memset(got_pov
, 0, 24);
520 unsigned int plt_offset
= plt_entry_size
;
521 unsigned int got_offset
= 24;
522 const unsigned int count
= this->count_
;
523 for (unsigned int plt_index
= 0;
526 pov
+= plt_entry_size
,
528 plt_offset
+= plt_entry_size
,
531 // Set and adjust the PLT entry itself.
532 memcpy(pov
, plt_entry
, plt_entry_size
);
533 if (parameters
->output_is_shared())
534 // FIXME(csilvers): what's the right thing to write here?
535 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_offset
);
537 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
538 (got_address
+ got_offset
539 - (plt_address
+ plt_offset
542 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_index
);
543 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
544 - (plt_offset
+ plt_entry_size
));
546 // Set the entry in the GOT.
547 elfcpp::Swap
<64, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
550 gold_assert(pov
- oview
== oview_size
);
551 gold_assert(got_pov
- got_view
== got_size
);
553 of
->write_output_view(offset
, oview_size
, oview
);
554 of
->write_output_view(got_file_offset
, got_size
, got_view
);
557 // Create a PLT entry for a global symbol.
560 Target_x86_64::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
563 if (gsym
->has_plt_offset())
566 if (this->plt_
== NULL
)
568 // Create the GOT sections first.
569 this->got_section(symtab
, layout
);
571 this->plt_
= new Output_data_plt_x86_64(layout
, this->got_plt_
);
572 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
574 | elfcpp::SHF_EXECINSTR
),
578 this->plt_
->add_entry(gsym
);
581 // Handle a relocation against a non-function symbol defined in a
582 // dynamic object. The traditional way to handle this is to generate
583 // a COPY relocation to copy the variable at runtime from the shared
584 // object into the executable's data segment. However, this is
585 // undesirable in general, as if the size of the object changes in the
586 // dynamic object, the executable will no longer work correctly. If
587 // this relocation is in a writable section, then we can create a
588 // dynamic reloc and the dynamic linker will resolve it to the correct
589 // address at runtime. However, we do not want do that if the
590 // relocation is in a read-only section, as it would prevent the
591 // readonly segment from being shared. And if we have to eventually
592 // generate a COPY reloc, then any dynamic relocations will be
593 // useless. So this means that if this is a writable section, we need
594 // to save the relocation until we see whether we have to create a
595 // COPY relocation for this symbol for any other relocation.
598 Target_x86_64::copy_reloc(const General_options
* options
,
599 Symbol_table
* symtab
,
601 Sized_relobj
<64, false>* object
,
602 unsigned int data_shndx
, Symbol
* gsym
,
603 const elfcpp::Rela
<64, false>& rela
)
605 Sized_symbol
<64>* ssym
;
606 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(64) (gsym
609 if (!Copy_relocs
<64, false>::need_copy_reloc(options
, object
,
612 // So far we do not need a COPY reloc. Save this relocation.
613 // If it turns out that we never need a COPY reloc for this
614 // symbol, then we will emit the relocation.
615 if (this->copy_relocs_
== NULL
)
616 this->copy_relocs_
= new Copy_relocs
<64, false>();
617 this->copy_relocs_
->save(ssym
, object
, data_shndx
, rela
);
621 // Allocate space for this symbol in the .bss section.
623 elfcpp::Elf_types
<64>::Elf_WXword symsize
= ssym
->symsize();
625 // There is no defined way to determine the required alignment
626 // of the symbol. We pick the alignment based on the size. We
627 // set an arbitrary maximum of 256.
629 for (align
= 1; align
< 512; align
<<= 1)
630 if ((symsize
& align
) != 0)
633 if (this->dynbss_
== NULL
)
635 this->dynbss_
= new Output_data_space(align
);
636 layout
->add_output_section_data(".bss",
639 | elfcpp::SHF_WRITE
),
643 Output_data_space
* dynbss
= this->dynbss_
;
645 if (align
> dynbss
->addralign())
646 dynbss
->set_space_alignment(align
);
648 off_t dynbss_size
= dynbss
->data_size();
649 dynbss_size
= align_address(dynbss_size
, align
);
650 off_t offset
= dynbss_size
;
651 dynbss
->set_space_size(dynbss_size
+ symsize
);
653 symtab
->define_with_copy_reloc(this, ssym
, dynbss
, offset
);
655 // Add the COPY reloc.
656 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
657 rela_dyn
->add_global(ssym
, elfcpp::R_X86_64_COPY
, dynbss
, offset
, 0);
662 // Optimize the TLS relocation type based on what we know about the
663 // symbol. IS_FINAL is true if the final address of this symbol is
664 // known at link time.
666 tls::Tls_optimization
667 Target_x86_64::optimize_tls_reloc(bool is_final
, int r_type
)
669 // If we are generating a shared library, then we can't do anything
671 if (parameters
->output_is_shared())
672 return tls::TLSOPT_NONE
;
676 case elfcpp::R_X86_64_TLSGD
:
677 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
678 case elfcpp::R_X86_64_TLSDESC_CALL
:
679 // These are General-Dynamic which permits fully general TLS
680 // access. Since we know that we are generating an executable,
681 // we can convert this to Initial-Exec. If we also know that
682 // this is a local symbol, we can further switch to Local-Exec.
684 return tls::TLSOPT_TO_LE
;
685 return tls::TLSOPT_TO_IE
;
687 case elfcpp::R_X86_64_TLSLD
:
688 // This is Local-Dynamic, which refers to a local symbol in the
689 // dynamic TLS block. Since we know that we generating an
690 // executable, we can switch to Local-Exec.
691 return tls::TLSOPT_TO_LE
;
693 case elfcpp::R_X86_64_DTPOFF32
:
694 case elfcpp::R_X86_64_DTPOFF64
:
695 // Another Local-Dynamic reloc.
696 return tls::TLSOPT_TO_LE
;
698 case elfcpp::R_X86_64_GOTTPOFF
:
699 // These are Initial-Exec relocs which get the thread offset
700 // from the GOT. If we know that we are linking against the
701 // local symbol, we can switch to Local-Exec, which links the
702 // thread offset into the instruction.
704 return tls::TLSOPT_TO_LE
;
705 return tls::TLSOPT_NONE
;
707 case elfcpp::R_X86_64_TPOFF32
:
708 // When we already have Local-Exec, there is nothing further we
710 return tls::TLSOPT_NONE
;
717 // Report an unsupported relocation against a local symbol.
720 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj
<64, false>* object
,
723 gold_error(_("%s: unsupported reloc %u against local symbol"),
724 object
->name().c_str(), r_type
);
727 // Scan a relocation for a local symbol.
730 Target_x86_64::Scan::local(const General_options
&,
731 Symbol_table
* symtab
,
733 Target_x86_64
* target
,
734 Sized_relobj
<64, false>* object
,
735 unsigned int data_shndx
,
736 const elfcpp::Rela
<64, false>& reloc
,
738 const elfcpp::Sym
<64, false>&)
742 case elfcpp::R_X86_64_NONE
:
743 case elfcpp::R_386_GNU_VTINHERIT
:
744 case elfcpp::R_386_GNU_VTENTRY
:
747 case elfcpp::R_X86_64_64
:
748 // If building a shared library (or a position-independent
749 // executable), we need to create a dynamic relocation for
750 // this location. The relocation applied at link time will
751 // apply the link-time value, so we flag the location with
752 // an R_386_RELATIVE relocation so the dynamic loader can
753 // relocate it easily.
754 if (parameters
->output_is_position_independent())
756 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
757 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
758 data_shndx
, reloc
.get_r_offset(), 0);
762 case elfcpp::R_X86_64_32
:
763 case elfcpp::R_X86_64_32S
:
764 case elfcpp::R_X86_64_16
:
765 case elfcpp::R_X86_64_8
:
766 // If building a shared library (or a position-independent
767 // executable), we need to create a dynamic relocation for
768 // this location. The relocation applied at link time will
769 // apply the link-time value, so we flag the location with
770 // an R_386_RELATIVE relocation so the dynamic loader can
771 // relocate it easily.
772 if (parameters
->output_is_position_independent())
774 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
775 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
776 rela_dyn
->add_local(object
, r_sym
, r_type
, data_shndx
,
777 reloc
.get_r_offset(),
778 reloc
.get_r_addend());
782 case elfcpp::R_X86_64_PC64
:
783 case elfcpp::R_X86_64_PC32
:
784 case elfcpp::R_X86_64_PC16
:
785 case elfcpp::R_X86_64_PC8
:
788 case elfcpp::R_X86_64_PLT32
:
789 // Since we know this is a local symbol, we can handle this as a
793 case elfcpp::R_X86_64_GOTPC32
:
794 case elfcpp::R_X86_64_GOTOFF64
:
795 case elfcpp::R_X86_64_GOTPC64
:
796 case elfcpp::R_X86_64_PLTOFF64
:
797 // We need a GOT section.
798 target
->got_section(symtab
, layout
);
799 // For PLTOFF64, we'd normally want a PLT section, but since we
800 // know this is a local symbol, no PLT is needed.
803 case elfcpp::R_X86_64_GOT64
:
804 case elfcpp::R_X86_64_GOT32
:
805 case elfcpp::R_X86_64_GOTPCREL64
:
806 case elfcpp::R_X86_64_GOTPCREL
:
807 case elfcpp::R_X86_64_GOTPLT64
:
809 // The symbol requires a GOT entry.
810 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
811 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
812 if (got
->add_local(object
, r_sym
))
814 // If we are generating a shared object, we need to add a
815 // dynamic RELATIVE relocation for this symbol.
816 if (parameters
->output_is_position_independent())
818 // FIXME: R_X86_64_RELATIVE assumes a 64-bit relocation.
819 gold_assert(r_type
!= elfcpp::R_X86_64_GOT32
);
821 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
822 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
823 data_shndx
, reloc
.get_r_offset(), 0);
826 // For GOTPLT64, we'd normally want a PLT section, but since
827 // we know this is a local symbol, no PLT is needed.
831 case elfcpp::R_X86_64_COPY
:
832 case elfcpp::R_X86_64_GLOB_DAT
:
833 case elfcpp::R_X86_64_JUMP_SLOT
:
834 case elfcpp::R_X86_64_RELATIVE
:
835 // These are outstanding tls relocs, which are unexpected when linking
836 case elfcpp::R_X86_64_TPOFF64
:
837 case elfcpp::R_X86_64_DTPMOD64
:
838 case elfcpp::R_X86_64_TLSDESC
:
839 gold_error(_("%s: unexpected reloc %u in object file"),
840 object
->name().c_str(), r_type
);
843 // These are initial tls relocs, which are expected when linking
844 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
845 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
846 case elfcpp::R_X86_64_TLSDESC_CALL
:
847 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
848 case elfcpp::R_X86_64_DTPOFF32
:
849 case elfcpp::R_X86_64_DTPOFF64
:
850 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
851 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
853 bool output_is_shared
= parameters
->output_is_shared();
854 const tls::Tls_optimization optimized_type
855 = Target_x86_64::optimize_tls_reloc(!output_is_shared
, r_type
);
858 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
859 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
860 case elfcpp::R_X86_64_TLSDESC_CALL
:
861 // FIXME: If not relaxing to LE, we need to generate
862 // DTPMOD64 and DTPOFF64 relocs.
863 if (optimized_type
!= tls::TLSOPT_TO_LE
)
864 unsupported_reloc_local(object
, r_type
);
867 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
868 case elfcpp::R_X86_64_DTPOFF32
:
869 case elfcpp::R_X86_64_DTPOFF64
:
870 // FIXME: If not relaxing to LE, we need to generate a
872 if (optimized_type
!= tls::TLSOPT_TO_LE
)
873 unsupported_reloc_local(object
, r_type
);
876 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
877 // FIXME: If not relaxing to LE, we need to generate a
879 if (optimized_type
!= tls::TLSOPT_TO_LE
)
880 unsupported_reloc_local(object
, r_type
);
883 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
884 // FIXME: If generating a shared object, we need to copy
885 // this relocation into the object.
886 gold_assert(!output_is_shared
);
895 case elfcpp::R_X86_64_SIZE32
:
896 case elfcpp::R_X86_64_SIZE64
:
898 gold_error(_("%s: unsupported reloc %u against local symbol"),
899 object
->name().c_str(), r_type
);
905 // Report an unsupported relocation against a global symbol.
908 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj
<64, false>* object
,
912 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
913 object
->name().c_str(), r_type
, gsym
->name());
916 // Scan a relocation for a global symbol.
919 Target_x86_64::Scan::global(const General_options
& options
,
920 Symbol_table
* symtab
,
922 Target_x86_64
* target
,
923 Sized_relobj
<64, false>* object
,
924 unsigned int data_shndx
,
925 const elfcpp::Rela
<64, false>& reloc
,
931 case elfcpp::R_X86_64_NONE
:
932 case elfcpp::R_386_GNU_VTINHERIT
:
933 case elfcpp::R_386_GNU_VTENTRY
:
936 case elfcpp::R_X86_64_64
:
937 case elfcpp::R_X86_64_32
:
938 case elfcpp::R_X86_64_32S
:
939 case elfcpp::R_X86_64_16
:
940 case elfcpp::R_X86_64_8
:
942 // Make a PLT entry if necessary.
943 if (gsym
->needs_plt_entry())
945 target
->make_plt_entry(symtab
, layout
, gsym
);
946 // Since this is not a PC-relative relocation, we may be
947 // taking the address of a function. In that case we need to
948 // set the entry in the dynamic symbol table to the address of
950 if (gsym
->is_from_dynobj())
951 gsym
->set_needs_dynsym_value();
953 // Make a dynamic relocation if necessary.
954 if (gsym
->needs_dynamic_reloc(true, false))
956 if (target
->may_need_copy_reloc(gsym
))
958 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
961 else if (r_type
== elfcpp::R_X86_64_64
962 && gsym
->can_use_relative_reloc(false))
964 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
965 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
967 reloc
.get_r_offset(), 0);
971 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
972 rela_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
973 reloc
.get_r_offset(),
974 reloc
.get_r_addend());
980 case elfcpp::R_X86_64_PC64
:
981 case elfcpp::R_X86_64_PC32
:
982 case elfcpp::R_X86_64_PC16
:
983 case elfcpp::R_X86_64_PC8
:
985 // Make a PLT entry if necessary.
986 if (gsym
->needs_plt_entry())
987 target
->make_plt_entry(symtab
, layout
, gsym
);
988 // Make a dynamic relocation if necessary.
989 bool is_function_call
= (gsym
->type() == elfcpp::STT_FUNC
);
990 if (gsym
->needs_dynamic_reloc(true, is_function_call
))
992 if (target
->may_need_copy_reloc(gsym
))
994 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
999 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1000 rela_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
1001 reloc
.get_r_offset(),
1002 reloc
.get_r_addend());
1008 case elfcpp::R_X86_64_GOT64
:
1009 case elfcpp::R_X86_64_GOT32
:
1010 case elfcpp::R_X86_64_GOTPCREL64
:
1011 case elfcpp::R_X86_64_GOTPCREL
:
1012 case elfcpp::R_X86_64_GOTPLT64
:
1014 // The symbol requires a GOT entry.
1015 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
1016 if (got
->add_global(gsym
))
1018 // If this symbol is not fully resolved, we need to add a
1019 // dynamic relocation for it.
1020 if (!gsym
->final_value_is_known())
1022 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1023 if (gsym
->is_from_dynobj()
1024 || gsym
->is_preemptible())
1025 rela_dyn
->add_global(gsym
, elfcpp::R_X86_64_GLOB_DAT
, got
,
1026 gsym
->got_offset(), 0);
1029 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_RELATIVE
,
1030 got
, gsym
->got_offset(), 0);
1031 // Make sure we write the link-time value to the GOT.
1032 gsym
->set_needs_value_in_got();
1036 // For GOTPLT64, we also need a PLT entry (but only if the
1037 // symbol is not fully resolved).
1038 if (r_type
== elfcpp::R_X86_64_GOTPLT64
1039 && !gsym
->final_value_is_known())
1040 target
->make_plt_entry(symtab
, layout
, gsym
);
1044 case elfcpp::R_X86_64_PLT32
:
1045 // If the symbol is fully resolved, this is just a PC32 reloc.
1046 // Otherwise we need a PLT entry.
1047 if (gsym
->final_value_is_known())
1049 // If building a shared library, we can also skip the PLT entry
1050 // if the symbol is defined in the output file and is protected
1052 if (gsym
->is_defined()
1053 && !gsym
->is_from_dynobj()
1054 && !gsym
->is_preemptible())
1056 target
->make_plt_entry(symtab
, layout
, gsym
);
1059 case elfcpp::R_X86_64_GOTPC32
:
1060 case elfcpp::R_X86_64_GOTOFF64
:
1061 case elfcpp::R_X86_64_GOTPC64
:
1062 case elfcpp::R_X86_64_PLTOFF64
:
1063 // We need a GOT section.
1064 target
->got_section(symtab
, layout
);
1065 // For PLTOFF64, we also need a PLT entry (but only if the
1066 // symbol is not fully resolved).
1067 if (r_type
== elfcpp::R_X86_64_PLTOFF64
1068 && !gsym
->final_value_is_known())
1069 target
->make_plt_entry(symtab
, layout
, gsym
);
1072 case elfcpp::R_X86_64_COPY
:
1073 case elfcpp::R_X86_64_GLOB_DAT
:
1074 case elfcpp::R_X86_64_JUMP_SLOT
:
1075 case elfcpp::R_X86_64_RELATIVE
:
1076 // These are outstanding tls relocs, which are unexpected when linking
1077 case elfcpp::R_X86_64_TPOFF64
:
1078 case elfcpp::R_X86_64_DTPMOD64
:
1079 case elfcpp::R_X86_64_TLSDESC
:
1080 gold_error(_("%s: unexpected reloc %u in object file"),
1081 object
->name().c_str(), r_type
);
1084 // These are initial tls relocs, which are expected for global()
1085 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1086 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1087 case elfcpp::R_X86_64_TLSDESC_CALL
:
1088 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1089 case elfcpp::R_X86_64_DTPOFF32
:
1090 case elfcpp::R_X86_64_DTPOFF64
:
1091 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1092 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1094 const bool is_final
= gsym
->final_value_is_known();
1095 const tls::Tls_optimization optimized_type
1096 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
1099 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
1100 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
1101 case elfcpp::R_X86_64_TLSDESC_CALL
:
1102 // FIXME: If not relaxing to LE, we need to generate
1103 // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1104 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1105 unsupported_reloc_global(object
, r_type
, gsym
);
1108 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1109 case elfcpp::R_X86_64_DTPOFF32
:
1110 case elfcpp::R_X86_64_DTPOFF64
:
1111 // FIXME: If not relaxing to LE, we need to generate a
1113 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1114 unsupported_reloc_global(object
, r_type
, gsym
);
1117 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1118 // FIXME: If not relaxing to LE, we need to generate a
1120 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1121 unsupported_reloc_global(object
, r_type
, gsym
);
1124 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1125 // FIXME: If generating a shared object, we need to copy
1126 // this relocation into the object.
1127 gold_assert(is_final
);
1136 case elfcpp::R_X86_64_SIZE32
:
1137 case elfcpp::R_X86_64_SIZE64
:
1139 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1140 object
->name().c_str(), r_type
, gsym
->name());
1145 // Scan relocations for a section.
1148 Target_x86_64::scan_relocs(const General_options
& options
,
1149 Symbol_table
* symtab
,
1151 Sized_relobj
<64, false>* object
,
1152 unsigned int data_shndx
,
1153 unsigned int sh_type
,
1154 const unsigned char* prelocs
,
1156 Output_section
* output_section
,
1157 bool needs_special_offset_handling
,
1158 size_t local_symbol_count
,
1159 const unsigned char* plocal_symbols
)
1161 if (sh_type
== elfcpp::SHT_REL
)
1163 gold_error(_("%s: unsupported REL reloc section"),
1164 object
->name().c_str());
1168 gold::scan_relocs
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
1169 Target_x86_64::Scan
>(
1179 needs_special_offset_handling
,
1184 // Finalize the sections.
1187 Target_x86_64::do_finalize_sections(Layout
* layout
)
1189 // Fill in some more dynamic tags.
1190 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1193 if (this->got_plt_
!= NULL
)
1194 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1196 if (this->plt_
!= NULL
)
1198 const Output_data
* od
= this->plt_
->rel_plt();
1199 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1200 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1201 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_RELA
);
1204 if (this->rela_dyn_
!= NULL
)
1206 const Output_data
* od
= this->rela_dyn_
;
1207 odyn
->add_section_address(elfcpp::DT_RELA
, od
);
1208 odyn
->add_section_size(elfcpp::DT_RELASZ
, od
);
1209 odyn
->add_constant(elfcpp::DT_RELAENT
,
1210 elfcpp::Elf_sizes
<64>::rela_size
);
1213 if (!parameters
->output_is_shared())
1215 // The value of the DT_DEBUG tag is filled in by the dynamic
1216 // linker at run time, and used by the debugger.
1217 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1221 // Emit any relocs we saved in an attempt to avoid generating COPY
1223 if (this->copy_relocs_
== NULL
)
1225 if (this->copy_relocs_
->any_to_emit())
1227 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
1228 this->copy_relocs_
->emit(rela_dyn
);
1230 delete this->copy_relocs_
;
1231 this->copy_relocs_
= NULL
;
1234 // Perform a relocation.
1237 Target_x86_64::Relocate::relocate(const Relocate_info
<64, false>* relinfo
,
1238 Target_x86_64
* target
,
1240 const elfcpp::Rela
<64, false>& rela
,
1241 unsigned int r_type
,
1242 const Sized_symbol
<64>* gsym
,
1243 const Symbol_value
<64>* psymval
,
1244 unsigned char* view
,
1245 elfcpp::Elf_types
<64>::Elf_Addr address
,
1248 if (this->skip_call_tls_get_addr_
)
1250 if (r_type
!= elfcpp::R_X86_64_PLT32
1252 || strcmp(gsym
->name(), "__tls_get_addr") != 0)
1254 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1255 _("missing expected TLS relocation"));
1259 this->skip_call_tls_get_addr_
= false;
1264 // Pick the value to use for symbols defined in shared objects.
1265 Symbol_value
<64> symval
;
1267 && (gsym
->is_from_dynobj()
1268 || (parameters
->output_is_shared()
1269 && gsym
->is_preemptible()))
1270 && gsym
->has_plt_offset())
1272 symval
.set_output_value(target
->plt_section()->address()
1273 + gsym
->plt_offset());
1277 const Sized_relobj
<64, false>* object
= relinfo
->object
;
1278 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
1280 // Get the GOT offset if needed.
1281 // The GOT pointer points to the end of the GOT section.
1282 // We need to subtract the size of the GOT section to get
1283 // the actual offset to use in the relocation.
1284 bool have_got_offset
= false;
1285 unsigned int got_offset
= 0;
1288 case elfcpp::R_X86_64_GOT32
:
1289 case elfcpp::R_X86_64_GOT64
:
1290 case elfcpp::R_X86_64_GOTPLT64
:
1291 case elfcpp::R_X86_64_GOTPCREL
:
1292 case elfcpp::R_X86_64_GOTPCREL64
:
1295 gold_assert(gsym
->has_got_offset());
1296 got_offset
= gsym
->got_offset() - target
->got_size();
1300 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
1301 got_offset
= object
->local_got_offset(r_sym
) - target
->got_size();
1303 have_got_offset
= true;
1312 case elfcpp::R_X86_64_NONE
:
1313 case elfcpp::R_386_GNU_VTINHERIT
:
1314 case elfcpp::R_386_GNU_VTENTRY
:
1317 case elfcpp::R_X86_64_64
:
1318 Relocate_functions
<64, false>::rela64(view
, object
, psymval
, addend
);
1321 case elfcpp::R_X86_64_PC64
:
1322 Relocate_functions
<64, false>::pcrela64(view
, object
, psymval
, addend
,
1326 case elfcpp::R_X86_64_32
:
1327 // FIXME: we need to verify that value + addend fits into 32 bits:
1328 // uint64_t x = value + addend;
1329 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1330 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1331 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
1334 case elfcpp::R_X86_64_32S
:
1335 // FIXME: we need to verify that value + addend fits into 32 bits:
1336 // int64_t x = value + addend; // note this quantity is signed!
1337 // x == static_cast<int64_t>(static_cast<int32_t>(x))
1338 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
1341 case elfcpp::R_X86_64_PC32
:
1342 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
1346 case elfcpp::R_X86_64_16
:
1347 Relocate_functions
<64, false>::rela16(view
, object
, psymval
, addend
);
1350 case elfcpp::R_X86_64_PC16
:
1351 Relocate_functions
<64, false>::pcrela16(view
, object
, psymval
, addend
,
1355 case elfcpp::R_X86_64_8
:
1356 Relocate_functions
<64, false>::rela8(view
, object
, psymval
, addend
);
1359 case elfcpp::R_X86_64_PC8
:
1360 Relocate_functions
<64, false>::pcrela8(view
, object
, psymval
, addend
,
1364 case elfcpp::R_X86_64_PLT32
:
1365 gold_assert(gsym
== NULL
1366 || gsym
->has_plt_offset()
1367 || gsym
->final_value_is_known());
1368 // Note: while this code looks the same as for R_X86_64_PC32, it
1369 // behaves differently because psymval was set to point to
1370 // the PLT entry, rather than the symbol, in Scan::global().
1371 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
1375 case elfcpp::R_X86_64_PLTOFF64
:
1378 gold_assert(gsym
->has_plt_offset()
1379 || gsym
->final_value_is_known());
1380 elfcpp::Elf_types
<64>::Elf_Addr got_address
;
1381 got_address
= target
->got_section(NULL
, NULL
)->address();
1382 Relocate_functions
<64, false>::rela64(view
, object
, psymval
,
1383 addend
- got_address
);
1386 case elfcpp::R_X86_64_GOT32
:
1387 gold_assert(have_got_offset
);
1388 Relocate_functions
<64, false>::rela32(view
, got_offset
, addend
);
1391 case elfcpp::R_X86_64_GOTPC32
:
1394 elfcpp::Elf_types
<64>::Elf_Addr value
;
1395 value
= target
->got_plt_section()->address();
1396 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
1400 case elfcpp::R_X86_64_GOT64
:
1401 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1402 // Since we always add a PLT entry, this is equivalent.
1403 case elfcpp::R_X86_64_GOTPLT64
:
1404 gold_assert(have_got_offset
);
1405 Relocate_functions
<64, false>::rela64(view
, got_offset
, addend
);
1408 case elfcpp::R_X86_64_GOTPC64
:
1411 elfcpp::Elf_types
<64>::Elf_Addr value
;
1412 value
= target
->got_plt_section()->address();
1413 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
1417 case elfcpp::R_X86_64_GOTOFF64
:
1419 elfcpp::Elf_types
<64>::Elf_Addr value
;
1420 value
= (psymval
->value(object
, 0)
1421 - target
->got_plt_section()->address());
1422 Relocate_functions
<64, false>::rela64(view
, value
, addend
);
1426 case elfcpp::R_X86_64_GOTPCREL
:
1428 gold_assert(have_got_offset
);
1429 elfcpp::Elf_types
<64>::Elf_Addr value
;
1430 value
= target
->got_plt_section()->address() + got_offset
;
1431 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
1435 case elfcpp::R_X86_64_GOTPCREL64
:
1437 gold_assert(have_got_offset
);
1438 elfcpp::Elf_types
<64>::Elf_Addr value
;
1439 value
= target
->got_plt_section()->address() + got_offset
;
1440 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
1444 case elfcpp::R_X86_64_COPY
:
1445 case elfcpp::R_X86_64_GLOB_DAT
:
1446 case elfcpp::R_X86_64_JUMP_SLOT
:
1447 case elfcpp::R_X86_64_RELATIVE
:
1448 // These are outstanding tls relocs, which are unexpected when linking
1449 case elfcpp::R_X86_64_TPOFF64
:
1450 case elfcpp::R_X86_64_DTPMOD64
:
1451 case elfcpp::R_X86_64_TLSDESC
:
1452 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1453 _("unexpected reloc %u in object file"),
1457 // These are initial tls relocs, which are expected when linking
1458 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1459 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1460 case elfcpp::R_X86_64_TLSDESC_CALL
:
1461 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1462 case elfcpp::R_X86_64_DTPOFF32
:
1463 case elfcpp::R_X86_64_DTPOFF64
:
1464 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1465 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1466 this->relocate_tls(relinfo
, relnum
, rela
, r_type
, gsym
, psymval
, view
,
1467 address
, view_size
);
1470 case elfcpp::R_X86_64_SIZE32
:
1471 case elfcpp::R_X86_64_SIZE64
:
1473 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1474 _("unsupported reloc %u"),
1482 // Perform a TLS relocation.
1485 Target_x86_64::Relocate::relocate_tls(const Relocate_info
<64, false>* relinfo
,
1487 const elfcpp::Rela
<64, false>& rela
,
1488 unsigned int r_type
,
1489 const Sized_symbol
<64>* gsym
,
1490 const Symbol_value
<64>* psymval
,
1491 unsigned char* view
,
1492 elfcpp::Elf_types
<64>::Elf_Addr
,
1495 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1496 if (tls_segment
== NULL
)
1498 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1499 _("TLS reloc but no TLS segment"));
1503 elfcpp::Elf_types
<64>::Elf_Addr value
= psymval
->value(relinfo
->object
, 0);
1505 const bool is_final
= (gsym
== NULL
1506 ? !parameters
->output_is_position_independent()
1507 : gsym
->final_value_is_known());
1508 const tls::Tls_optimization optimized_type
1509 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
1512 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1513 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1514 case elfcpp::R_X86_64_TLSDESC_CALL
:
1515 if (optimized_type
== tls::TLSOPT_TO_LE
)
1517 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1518 rela
, r_type
, value
, view
,
1522 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1523 _("unsupported reloc %u"), r_type
);
1526 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1527 if (optimized_type
== tls::TLSOPT_TO_LE
)
1529 this->tls_ld_to_le(relinfo
, relnum
, tls_segment
, rela
, r_type
,
1530 value
, view
, view_size
);
1533 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1534 _("unsupported reloc %u"), r_type
);
1537 case elfcpp::R_X86_64_DTPOFF32
:
1538 if (optimized_type
== tls::TLSOPT_TO_LE
)
1539 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1541 value
= value
- tls_segment
->vaddr();
1542 Relocate_functions
<64, false>::rel32(view
, value
);
1545 case elfcpp::R_X86_64_DTPOFF64
:
1546 if (optimized_type
== tls::TLSOPT_TO_LE
)
1547 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1549 value
= value
- tls_segment
->vaddr();
1550 Relocate_functions
<64, false>::rel64(view
, value
);
1553 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1554 if (optimized_type
== tls::TLSOPT_TO_LE
)
1556 Target_x86_64::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1557 rela
, r_type
, value
, view
,
1561 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
1562 _("unsupported reloc type %u"),
1566 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1567 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1568 Relocate_functions
<64, false>::rel32(view
, value
);
1573 // Do a relocation in which we convert a TLS General-Dynamic to a
1577 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info
<64, false>* relinfo
,
1579 Output_segment
* tls_segment
,
1580 const elfcpp::Rela
<64, false>& rela
,
1582 elfcpp::Elf_types
<64>::Elf_Addr value
,
1583 unsigned char* view
,
1586 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1587 // .word 0x6666; rex64; call __tls_get_addr
1588 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1590 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -4);
1591 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 12);
1593 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1594 (memcmp(view
- 4, "\x66\x48\x8d\x3d", 4) == 0));
1595 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1596 (memcmp(view
+ 4, "\x66\x66\x48\xe8", 4) == 0));
1598 memcpy(view
- 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1600 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1601 Relocate_functions
<64, false>::rela32(view
+ 8, value
, 0);
1603 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1605 this->skip_call_tls_get_addr_
= true;
1609 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info
<64, false>* relinfo
,
1612 const elfcpp::Rela
<64, false>& rela
,
1614 elfcpp::Elf_types
<64>::Elf_Addr
,
1615 unsigned char* view
,
1618 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1619 // ... leq foo@dtpoff(%rax),%reg
1620 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1622 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
1623 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 9);
1625 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
1626 view
[-3] == 0x48 && view
[-2] == 0x8d && view
[-1] == 0x3d);
1628 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(), view
[4] == 0xe8);
1630 memcpy(view
- 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1632 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1634 this->skip_call_tls_get_addr_
= true;
1637 // Do a relocation in which we convert a TLS Initial-Exec to a
1641 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info
<64, false>* relinfo
,
1643 Output_segment
* tls_segment
,
1644 const elfcpp::Rela
<64, false>& rela
,
1646 elfcpp::Elf_types
<64>::Elf_Addr value
,
1647 unsigned char* view
,
1650 // We need to examine the opcodes to figure out which instruction we
1653 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
1654 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
1656 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
1657 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 4);
1659 unsigned char op1
= view
[-3];
1660 unsigned char op2
= view
[-2];
1661 unsigned char op3
= view
[-1];
1662 unsigned char reg
= op3
>> 3;
1670 view
[-1] = 0xc0 | reg
;
1674 // Special handling for %rsp.
1678 view
[-1] = 0xc0 | reg
;
1686 view
[-1] = 0x80 | reg
| (reg
<< 3);
1689 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1690 Relocate_functions
<64, false>::rela32(view
, value
, 0);
1693 // Relocate section data.
1696 Target_x86_64::relocate_section(const Relocate_info
<64, false>* relinfo
,
1697 unsigned int sh_type
,
1698 const unsigned char* prelocs
,
1700 Output_section
* output_section
,
1701 bool needs_special_offset_handling
,
1702 unsigned char* view
,
1703 elfcpp::Elf_types
<64>::Elf_Addr address
,
1706 gold_assert(sh_type
== elfcpp::SHT_RELA
);
1708 gold::relocate_section
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
1709 Target_x86_64::Relocate
>(
1715 needs_special_offset_handling
,
1721 // Return the value to use for a dynamic which requires special
1722 // treatment. This is how we support equality comparisons of function
1723 // pointers across shared library boundaries, as described in the
1724 // processor specific ABI supplement.
1727 Target_x86_64::do_dynsym_value(const Symbol
* gsym
) const
1729 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1730 return this->plt_section()->address() + gsym
->plt_offset();
1733 // Return a string used to fill a code section with nops to take up
1734 // the specified length.
1737 Target_x86_64::do_code_fill(off_t length
)
1741 // Build a jmpq instruction to skip over the bytes.
1742 unsigned char jmp
[5];
1744 elfcpp::Swap_unaligned
<64, false>::writeval(jmp
+ 1, length
- 5);
1745 return (std::string(reinterpret_cast<char*>(&jmp
[0]), 5)
1746 + std::string(length
- 5, '\0'));
1749 // Nop sequences of various lengths.
1750 const char nop1
[1] = { 0x90 }; // nop
1751 const char nop2
[2] = { 0x66, 0x90 }; // xchg %ax %ax
1752 const char nop3
[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1753 const char nop4
[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1754 const char nop5
[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1755 0x00 }; // leal 0(%esi,1),%esi
1756 const char nop6
[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1758 const char nop7
[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1760 const char nop8
[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1761 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1762 const char nop9
[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1763 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1765 const char nop10
[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1766 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1768 const char nop11
[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1769 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1771 const char nop12
[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1772 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1773 0x00, 0x00, 0x00, 0x00 };
1774 const char nop13
[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1775 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1776 0x27, 0x00, 0x00, 0x00,
1778 const char nop14
[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1779 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1780 0xbc, 0x27, 0x00, 0x00,
1782 const char nop15
[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1783 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1784 0x90, 0x90, 0x90, 0x90,
1787 const char* nops
[16] = {
1789 nop1
, nop2
, nop3
, nop4
, nop5
, nop6
, nop7
,
1790 nop8
, nop9
, nop10
, nop11
, nop12
, nop13
, nop14
, nop15
1793 return std::string(nops
[length
], length
);
1796 // The selector for x86_64 object files.
1798 class Target_selector_x86_64
: public Target_selector
1801 Target_selector_x86_64()
1802 : Target_selector(elfcpp::EM_X86_64
, 64, false)
1806 recognize(int machine
, int osabi
, int abiversion
);
1809 Target_x86_64
* target_
;
1812 // Recognize an x86_64 object file when we already know that the machine
1813 // number is EM_X86_64.
1816 Target_selector_x86_64::recognize(int, int, int)
1818 if (this->target_
== NULL
)
1819 this->target_
= new Target_x86_64();
1820 return this->target_
;
1823 Target_selector_x86_64 target_selector_x86_64
;
1825 } // End anonymous namespace.