1 // i386.cc -- i386 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 modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
28 #include "parameters.h"
36 #include "target-reloc.h"
37 #include "target-select.h"
45 class Output_data_plt_i386
;
47 // The i386 target class.
48 // TLS info comes from
49 // http://people.redhat.com/drepper/tls.pdf
50 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
52 class Target_i386
: public Sized_target
<32, false>
55 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, false> Reloc_section
;
58 : Sized_target
<32, false>(&i386_info
),
59 got_(NULL
), plt_(NULL
), got_plt_(NULL
), rel_dyn_(NULL
),
60 copy_relocs_(NULL
), dynbss_(NULL
)
63 // Scan the relocations to look for symbol adjustments.
65 scan_relocs(const General_options
& options
,
68 Sized_relobj
<32, false>* object
,
69 unsigned int data_shndx
,
71 const unsigned char* prelocs
,
73 size_t local_symbol_count
,
74 const unsigned char* plocal_symbols
,
75 Symbol
** global_symbols
);
77 // Finalize the sections.
79 do_finalize_sections(Layout
*);
81 // Return the value to use for a dynamic which requires special
84 do_dynsym_value(const Symbol
*) const;
86 // Relocate a section.
88 relocate_section(const Relocate_info
<32, false>*,
90 const unsigned char* prelocs
,
93 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
96 // Return a string used to fill a code section with nops.
98 do_code_fill(off_t length
);
101 // The class which scans relocations.
105 local(const General_options
& options
, Symbol_table
* symtab
,
106 Layout
* layout
, Target_i386
* target
,
107 Sized_relobj
<32, false>* object
,
108 unsigned int data_shndx
,
109 const elfcpp::Rel
<32, false>& reloc
, unsigned int r_type
,
110 const elfcpp::Sym
<32, false>& lsym
);
113 global(const General_options
& options
, Symbol_table
* symtab
,
114 Layout
* layout
, Target_i386
* target
,
115 Sized_relobj
<32, false>* object
,
116 unsigned int data_shndx
,
117 const elfcpp::Rel
<32, false>& reloc
, unsigned int r_type
,
121 unsupported_reloc_local(Sized_relobj
<32, false>*, unsigned int r_type
);
124 unsupported_reloc_global(Sized_relobj
<32, false>*, unsigned int r_type
,
128 // The class which implements relocation.
133 : skip_call_tls_get_addr_(false),
134 local_dynamic_type_(LOCAL_DYNAMIC_NONE
)
139 if (this->skip_call_tls_get_addr_
)
141 // FIXME: This needs to specify the location somehow.
142 gold_error(_("missing expected TLS relocation"));
146 // Do a relocation. Return false if the caller should not issue
147 // any warnings about this relocation.
149 relocate(const Relocate_info
<32, false>*, Target_i386
*, size_t relnum
,
150 const elfcpp::Rel
<32, false>&,
151 unsigned int r_type
, const Sized_symbol
<32>*,
152 const Symbol_value
<32>*,
153 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
,
157 // Do a TLS relocation.
159 relocate_tls(const Relocate_info
<32, false>*, size_t relnum
,
160 const elfcpp::Rel
<32, false>&,
161 unsigned int r_type
, const Sized_symbol
<32>*,
162 const Symbol_value
<32>*,
163 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
, off_t
);
165 // Do a TLS Initial-Exec to Local-Exec transition.
167 tls_ie_to_le(const Relocate_info
<32, false>*, size_t relnum
,
168 Output_segment
* tls_segment
,
169 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
170 elfcpp::Elf_types
<32>::Elf_Addr value
,
174 // Do a TLS General-Dynamic to Local-Exec transition.
176 tls_gd_to_le(const Relocate_info
<32, false>*, size_t relnum
,
177 Output_segment
* tls_segment
,
178 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
179 elfcpp::Elf_types
<32>::Elf_Addr value
,
183 // Do a TLS Local-Dynamic to Local-Exec transition.
185 tls_ld_to_le(const Relocate_info
<32, false>*, size_t relnum
,
186 Output_segment
* tls_segment
,
187 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
188 elfcpp::Elf_types
<32>::Elf_Addr value
,
192 // We need to keep track of which type of local dynamic relocation
193 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
194 enum Local_dynamic_type
201 // This is set if we should skip the next reloc, which should be a
202 // PLT32 reloc against ___tls_get_addr.
203 bool skip_call_tls_get_addr_
;
204 // The type of local dynamic relocation we have seen in the section
205 // being relocated, if any.
206 Local_dynamic_type local_dynamic_type_
;
209 // Adjust TLS relocation type based on the options and whether this
210 // is a local symbol.
211 static tls::Tls_optimization
212 optimize_tls_reloc(bool is_final
, int r_type
);
214 // Get the GOT section, creating it if necessary.
215 Output_data_got
<32, false>*
216 got_section(Symbol_table
*, Layout
*);
218 // Create a PLT entry for a global symbol.
220 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
222 // Get the PLT section.
223 const Output_data_plt_i386
*
226 gold_assert(this->plt_
!= NULL
);
230 // Get the dynamic reloc section, creating it if necessary.
232 rel_dyn_section(Layout
*);
234 // Copy a relocation against a global symbol.
236 copy_reloc(const General_options
*, Symbol_table
*, Layout
*,
237 Sized_relobj
<32, false>*, unsigned int,
238 Symbol
*, const elfcpp::Rel
<32, false>&);
240 // Information about this specific target which we pass to the
241 // general Target structure.
242 static const Target::Target_info i386_info
;
245 Output_data_got
<32, false>* got_
;
247 Output_data_plt_i386
* plt_
;
248 // The GOT PLT section.
249 Output_data_space
* got_plt_
;
250 // The dynamic reloc section.
251 Reloc_section
* rel_dyn_
;
252 // Relocs saved to avoid a COPY reloc.
253 Copy_relocs
<32, false>* copy_relocs_
;
254 // Space for variables copied with a COPY reloc.
255 Output_data_space
* dynbss_
;
258 const Target::Target_info
Target_i386::i386_info
=
261 false, // is_big_endian
262 elfcpp::EM_386
, // machine_code
263 false, // has_make_symbol
264 false, // has_resolve
265 true, // has_code_fill
266 "/usr/lib/libc.so.1", // dynamic_linker
267 0x08048000, // default_text_segment_address
268 0x1000, // abi_pagesize
269 0x1000 // common_pagesize
272 // Get the GOT section, creating it if necessary.
274 Output_data_got
<32, false>*
275 Target_i386::got_section(Symbol_table
* symtab
, Layout
* layout
)
277 if (this->got_
== NULL
)
279 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
281 this->got_
= new Output_data_got
<32, false>();
283 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
284 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
287 // The old GNU linker creates a .got.plt section. We just
288 // create another set of data in the .got section. Note that we
289 // always create a PLT if we create a GOT, although the PLT
291 this->got_plt_
= new Output_data_space(4);
292 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
293 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
296 // The first three entries are reserved.
297 this->got_plt_
->set_space_size(3 * 4);
299 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
300 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL
,
302 0, 0, elfcpp::STT_OBJECT
,
304 elfcpp::STV_HIDDEN
, 0,
311 // Get the dynamic reloc section, creating it if necessary.
313 Target_i386::Reloc_section
*
314 Target_i386::rel_dyn_section(Layout
* layout
)
316 if (this->rel_dyn_
== NULL
)
318 gold_assert(layout
!= NULL
);
319 this->rel_dyn_
= new Reloc_section();
320 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
321 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
323 return this->rel_dyn_
;
326 // A class to handle the PLT data.
328 class Output_data_plt_i386
: public Output_section_data
331 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, false> Reloc_section
;
333 Output_data_plt_i386(Layout
*, Output_data_space
*);
335 // Add an entry to the PLT.
337 add_entry(Symbol
* gsym
);
339 // Return the .rel.plt section data.
342 { return this->rel_
; }
346 do_adjust_output_section(Output_section
* os
);
349 // The size of an entry in the PLT.
350 static const int plt_entry_size
= 16;
352 // The first entry in the PLT for an executable.
353 static unsigned char exec_first_plt_entry
[plt_entry_size
];
355 // The first entry in the PLT for a shared object.
356 static unsigned char dyn_first_plt_entry
[plt_entry_size
];
358 // Other entries in the PLT for an executable.
359 static unsigned char exec_plt_entry
[plt_entry_size
];
361 // Other entries in the PLT for a shared object.
362 static unsigned char dyn_plt_entry
[plt_entry_size
];
364 // Set the final size.
366 do_set_address(uint64_t, off_t
)
367 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
369 // Write out the PLT data.
371 do_write(Output_file
*);
373 // The reloc section.
375 // The .got.plt section.
376 Output_data_space
* got_plt_
;
377 // The number of PLT entries.
381 // Create the PLT section. The ordinary .got section is an argument,
382 // since we need to refer to the start. We also create our own .got
383 // section just for PLT entries.
385 Output_data_plt_i386::Output_data_plt_i386(Layout
* layout
,
386 Output_data_space
* got_plt
)
387 : Output_section_data(4), got_plt_(got_plt
), count_(0)
389 this->rel_
= new Reloc_section();
390 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
391 elfcpp::SHF_ALLOC
, this->rel_
);
395 Output_data_plt_i386::do_adjust_output_section(Output_section
* os
)
397 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
398 // linker, and so do we.
402 // Add an entry to the PLT.
405 Output_data_plt_i386::add_entry(Symbol
* gsym
)
407 gold_assert(!gsym
->has_plt_offset());
409 // Note that when setting the PLT offset we skip the initial
410 // reserved PLT entry.
411 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
415 off_t got_offset
= this->got_plt_
->data_size();
417 // Every PLT entry needs a GOT entry which points back to the PLT
418 // entry (this will be changed by the dynamic linker, normally
419 // lazily when the function is called).
420 this->got_plt_
->set_space_size(got_offset
+ 4);
422 // Every PLT entry needs a reloc.
423 gsym
->set_needs_dynsym_entry();
424 this->rel_
->add_global(gsym
, elfcpp::R_386_JUMP_SLOT
, this->got_plt_
,
427 // Note that we don't need to save the symbol. The contents of the
428 // PLT are independent of which symbols are used. The symbols only
429 // appear in the relocations.
432 // The first entry in the PLT for an executable.
434 unsigned char Output_data_plt_i386::exec_first_plt_entry
[plt_entry_size
] =
436 0xff, 0x35, // pushl contents of memory address
437 0, 0, 0, 0, // replaced with address of .got + 4
438 0xff, 0x25, // jmp indirect
439 0, 0, 0, 0, // replaced with address of .got + 8
443 // The first entry in the PLT for a shared object.
445 unsigned char Output_data_plt_i386::dyn_first_plt_entry
[plt_entry_size
] =
447 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
448 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
452 // Subsequent entries in the PLT for an executable.
454 unsigned char Output_data_plt_i386::exec_plt_entry
[plt_entry_size
] =
456 0xff, 0x25, // jmp indirect
457 0, 0, 0, 0, // replaced with address of symbol in .got
458 0x68, // pushl immediate
459 0, 0, 0, 0, // replaced with offset into relocation table
460 0xe9, // jmp relative
461 0, 0, 0, 0 // replaced with offset to start of .plt
464 // Subsequent entries in the PLT for a shared object.
466 unsigned char Output_data_plt_i386::dyn_plt_entry
[plt_entry_size
] =
468 0xff, 0xa3, // jmp *offset(%ebx)
469 0, 0, 0, 0, // replaced with offset of symbol in .got
470 0x68, // pushl immediate
471 0, 0, 0, 0, // replaced with offset into relocation table
472 0xe9, // jmp relative
473 0, 0, 0, 0 // replaced with offset to start of .plt
476 // Write out the PLT. This uses the hand-coded instructions above,
477 // and adjusts them as needed. This is all specified by the i386 ELF
478 // Processor Supplement.
481 Output_data_plt_i386::do_write(Output_file
* of
)
483 const off_t offset
= this->offset();
484 const off_t oview_size
= this->data_size();
485 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
487 const off_t got_file_offset
= this->got_plt_
->offset();
488 const off_t got_size
= this->got_plt_
->data_size();
489 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
492 unsigned char* pov
= oview
;
494 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
495 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
497 if (parameters
->output_is_shared())
498 memcpy(pov
, dyn_first_plt_entry
, plt_entry_size
);
501 memcpy(pov
, exec_first_plt_entry
, plt_entry_size
);
502 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 4);
503 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 8);
505 pov
+= plt_entry_size
;
507 unsigned char* got_pov
= got_view
;
509 memset(got_pov
, 0, 12);
512 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
514 unsigned int plt_offset
= plt_entry_size
;
515 unsigned int plt_rel_offset
= 0;
516 unsigned int got_offset
= 12;
517 const unsigned int count
= this->count_
;
518 for (unsigned int i
= 0;
521 pov
+= plt_entry_size
,
523 plt_offset
+= plt_entry_size
,
524 plt_rel_offset
+= rel_size
,
527 // Set and adjust the PLT entry itself.
529 if (parameters
->output_is_shared())
531 memcpy(pov
, dyn_plt_entry
, plt_entry_size
);
532 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_offset
);
536 memcpy(pov
, exec_plt_entry
, plt_entry_size
);
537 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
542 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_rel_offset
);
543 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
544 - (plt_offset
+ plt_entry_size
));
546 // Set the entry in the GOT.
547 elfcpp::Swap
<32, 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_i386::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
, Symbol
* gsym
)
562 if (gsym
->has_plt_offset())
565 if (this->plt_
== NULL
)
567 // Create the GOT sections first.
568 this->got_section(symtab
, layout
);
570 this->plt_
= new Output_data_plt_i386(layout
, this->got_plt_
);
571 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
573 | elfcpp::SHF_EXECINSTR
),
577 this->plt_
->add_entry(gsym
);
580 // Handle a relocation against a non-function symbol defined in a
581 // dynamic object. The traditional way to handle this is to generate
582 // a COPY relocation to copy the variable at runtime from the shared
583 // object into the executable's data segment. However, this is
584 // undesirable in general, as if the size of the object changes in the
585 // dynamic object, the executable will no longer work correctly. If
586 // this relocation is in a writable section, then we can create a
587 // dynamic reloc and the dynamic linker will resolve it to the correct
588 // address at runtime. However, we do not want do that if the
589 // relocation is in a read-only section, as it would prevent the
590 // readonly segment from being shared. And if we have to eventually
591 // generate a COPY reloc, then any dynamic relocations will be
592 // useless. So this means that if this is a writable section, we need
593 // to save the relocation until we see whether we have to create a
594 // COPY relocation for this symbol for any other relocation.
597 Target_i386::copy_reloc(const General_options
* options
,
598 Symbol_table
* symtab
,
600 Sized_relobj
<32, false>* object
,
601 unsigned int data_shndx
, Symbol
* gsym
,
602 const elfcpp::Rel
<32, false>& rel
)
604 Sized_symbol
<32>* ssym
;
605 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(32) (gsym
608 if (!Copy_relocs
<32, false>::need_copy_reloc(options
, object
,
611 // So far we do not need a COPY reloc. Save this relocation.
612 // If it turns out that we never need a COPY reloc for this
613 // symbol, then we will emit the relocation.
614 if (this->copy_relocs_
== NULL
)
615 this->copy_relocs_
= new Copy_relocs
<32, false>();
616 this->copy_relocs_
->save(ssym
, object
, data_shndx
, rel
);
620 // Allocate space for this symbol in the .bss section.
622 elfcpp::Elf_types
<32>::Elf_WXword symsize
= ssym
->symsize();
624 // There is no defined way to determine the required alignment
625 // of the symbol. We pick the alignment based on the size. We
626 // set an arbitrary maximum of 256.
628 for (align
= 1; align
< 512; align
<<= 1)
629 if ((symsize
& align
) != 0)
632 if (this->dynbss_
== NULL
)
634 this->dynbss_
= new Output_data_space(align
);
635 layout
->add_output_section_data(".bss",
638 | elfcpp::SHF_WRITE
),
642 Output_data_space
* dynbss
= this->dynbss_
;
644 if (align
> dynbss
->addralign())
645 dynbss
->set_space_alignment(align
);
647 off_t dynbss_size
= dynbss
->data_size();
648 dynbss_size
= align_address(dynbss_size
, align
);
649 off_t offset
= dynbss_size
;
650 dynbss
->set_space_size(dynbss_size
+ symsize
);
652 // Define the symbol in the .dynbss section.
653 symtab
->define_in_output_data(this, ssym
->name(), ssym
->version(),
654 dynbss
, offset
, symsize
, ssym
->type(),
655 ssym
->binding(), ssym
->visibility(),
656 ssym
->nonvis(), false, false);
658 // Add the COPY reloc.
659 ssym
->set_needs_dynsym_entry();
660 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
661 rel_dyn
->add_global(ssym
, elfcpp::R_386_COPY
, dynbss
, offset
);
665 // Optimize the TLS relocation type based on what we know about the
666 // symbol. IS_FINAL is true if the final address of this symbol is
667 // known at link time.
669 tls::Tls_optimization
670 Target_i386::optimize_tls_reloc(bool is_final
, int r_type
)
672 // If we are generating a shared library, then we can't do anything
674 if (parameters
->output_is_shared())
675 return tls::TLSOPT_NONE
;
679 case elfcpp::R_386_TLS_GD
:
680 case elfcpp::R_386_TLS_GOTDESC
:
681 case elfcpp::R_386_TLS_DESC_CALL
:
682 // These are General-Dynamic which permits fully general TLS
683 // access. Since we know that we are generating an executable,
684 // we can convert this to Initial-Exec. If we also know that
685 // this is a local symbol, we can further switch to Local-Exec.
687 return tls::TLSOPT_TO_LE
;
688 return tls::TLSOPT_TO_IE
;
690 case elfcpp::R_386_TLS_LDM
:
691 // This is Local-Dynamic, which refers to a local symbol in the
692 // dynamic TLS block. Since we know that we generating an
693 // executable, we can switch to Local-Exec.
694 return tls::TLSOPT_TO_LE
;
696 case elfcpp::R_386_TLS_LDO_32
:
697 // Another type of Local-Dynamic relocation.
698 return tls::TLSOPT_TO_LE
;
700 case elfcpp::R_386_TLS_IE
:
701 case elfcpp::R_386_TLS_GOTIE
:
702 case elfcpp::R_386_TLS_IE_32
:
703 // These are Initial-Exec relocs which get the thread offset
704 // from the GOT. If we know that we are linking against the
705 // local symbol, we can switch to Local-Exec, which links the
706 // thread offset into the instruction.
708 return tls::TLSOPT_TO_LE
;
709 return tls::TLSOPT_NONE
;
711 case elfcpp::R_386_TLS_LE
:
712 case elfcpp::R_386_TLS_LE_32
:
713 // When we already have Local-Exec, there is nothing further we
715 return tls::TLSOPT_NONE
;
722 // Report an unsupported relocation against a local symbol.
725 Target_i386::Scan::unsupported_reloc_local(Sized_relobj
<32, false>* object
,
728 gold_error(_("%s: unsupported reloc %u against local symbol"),
729 object
->name().c_str(), r_type
);
732 // Scan a relocation for a local symbol.
735 Target_i386::Scan::local(const General_options
&,
736 Symbol_table
* symtab
,
739 Sized_relobj
<32, false>* object
,
740 unsigned int data_shndx
,
741 const elfcpp::Rel
<32, false>& reloc
,
743 const elfcpp::Sym
<32, false>&)
747 case elfcpp::R_386_NONE
:
748 case elfcpp::R_386_GNU_VTINHERIT
:
749 case elfcpp::R_386_GNU_VTENTRY
:
752 case elfcpp::R_386_32
:
753 case elfcpp::R_386_16
:
754 case elfcpp::R_386_8
:
755 // If building a shared library (or a position-independent
756 // executable), we need to create a dynamic relocation for
757 // this location. The relocation applied at link time will
758 // apply the link-time value, so we flag the location with
759 // an R_386_RELATIVE relocation so the dynamic loader can
760 // relocate it easily.
761 if (parameters
->output_is_position_independent())
763 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
764 rel_dyn
->add_local(object
, 0, elfcpp::R_386_RELATIVE
, data_shndx
,
765 reloc
.get_r_offset());
769 case elfcpp::R_386_PC32
:
770 case elfcpp::R_386_PC16
:
771 case elfcpp::R_386_PC8
:
774 case elfcpp::R_386_GOTOFF
:
775 case elfcpp::R_386_GOTPC
:
776 // We need a GOT section.
777 target
->got_section(symtab
, layout
);
780 case elfcpp::R_386_GOT32
:
782 // The symbol requires a GOT entry.
783 Output_data_got
<32, false>* got
= target
->got_section(symtab
, layout
);
784 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
785 if (got
->add_local(object
, r_sym
))
787 // If we are generating a shared object, we need to add a
788 // dynamic RELATIVE relocation for this symbol.
789 if (parameters
->output_is_position_independent())
791 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
792 rel_dyn
->add_local(object
, 0, elfcpp::R_386_RELATIVE
,
793 data_shndx
, reloc
.get_r_offset());
799 // These are relocations which should only be seen by the
800 // dynamic linker, and should never be seen here.
801 case elfcpp::R_386_COPY
:
802 case elfcpp::R_386_GLOB_DAT
:
803 case elfcpp::R_386_JUMP_SLOT
:
804 case elfcpp::R_386_RELATIVE
:
805 case elfcpp::R_386_TLS_TPOFF
:
806 case elfcpp::R_386_TLS_DTPMOD32
:
807 case elfcpp::R_386_TLS_DTPOFF32
:
808 case elfcpp::R_386_TLS_TPOFF32
:
809 case elfcpp::R_386_TLS_DESC
:
810 gold_error(_("%s: unexpected reloc %u in object file"),
811 object
->name().c_str(), r_type
);
814 // These are initial TLS relocs, which are expected when
816 case elfcpp::R_386_TLS_IE
:
817 case elfcpp::R_386_TLS_GOTIE
:
818 case elfcpp::R_386_TLS_LE
:
819 case elfcpp::R_386_TLS_GD
:
820 case elfcpp::R_386_TLS_LDM
:
821 case elfcpp::R_386_TLS_LDO_32
:
822 case elfcpp::R_386_TLS_IE_32
:
823 case elfcpp::R_386_TLS_LE_32
:
824 case elfcpp::R_386_TLS_GOTDESC
:
825 case elfcpp::R_386_TLS_DESC_CALL
:
827 bool output_is_shared
= parameters
->output_is_shared();
828 const tls::Tls_optimization optimized_type
829 = Target_i386::optimize_tls_reloc(!output_is_shared
, r_type
);
832 case elfcpp::R_386_TLS_LE
:
833 case elfcpp::R_386_TLS_LE_32
:
834 // FIXME: If generating a shared object, we need to copy
835 // this relocation into the object.
836 gold_assert(!output_is_shared
);
839 case elfcpp::R_386_TLS_IE
:
840 case elfcpp::R_386_TLS_IE_32
:
841 case elfcpp::R_386_TLS_GOTIE
:
842 // FIXME: If not relaxing to LE, we need to generate a
843 // TPOFF or TPOFF32 reloc.
844 if (optimized_type
!= tls::TLSOPT_TO_LE
)
845 unsupported_reloc_local(object
, r_type
);
848 case elfcpp::R_386_TLS_LDM
:
849 // FIXME: If not relaxing to LE, we need to generate a
851 if (optimized_type
!= tls::TLSOPT_TO_LE
)
852 unsupported_reloc_local(object
, r_type
);
855 case elfcpp::R_386_TLS_LDO_32
:
858 case elfcpp::R_386_TLS_GD
:
859 case elfcpp::R_386_TLS_GOTDESC
:
860 case elfcpp::R_386_TLS_DESC_CALL
:
861 // FIXME: If not relaxing to LE, we need to generate
862 // DTPMOD32 and DTPOFF32 relocs.
863 if (optimized_type
!= tls::TLSOPT_TO_LE
)
864 unsupported_reloc_local(object
, r_type
);
873 case elfcpp::R_386_PLT32
:
874 case elfcpp::R_386_32PLT
:
875 case elfcpp::R_386_TLS_GD_32
:
876 case elfcpp::R_386_TLS_GD_PUSH
:
877 case elfcpp::R_386_TLS_GD_CALL
:
878 case elfcpp::R_386_TLS_GD_POP
:
879 case elfcpp::R_386_TLS_LDM_32
:
880 case elfcpp::R_386_TLS_LDM_PUSH
:
881 case elfcpp::R_386_TLS_LDM_CALL
:
882 case elfcpp::R_386_TLS_LDM_POP
:
883 case elfcpp::R_386_USED_BY_INTEL_200
:
885 unsupported_reloc_local(object
, r_type
);
890 // Report an unsupported relocation against a global symbol.
893 Target_i386::Scan::unsupported_reloc_global(Sized_relobj
<32, false>* object
,
897 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
898 object
->name().c_str(), r_type
, gsym
->name());
901 // Scan a relocation for a global symbol.
904 Target_i386::Scan::global(const General_options
& options
,
905 Symbol_table
* symtab
,
908 Sized_relobj
<32, false>* object
,
909 unsigned int data_shndx
,
910 const elfcpp::Rel
<32, false>& reloc
,
916 case elfcpp::R_386_NONE
:
917 case elfcpp::R_386_GNU_VTINHERIT
:
918 case elfcpp::R_386_GNU_VTENTRY
:
921 case elfcpp::R_386_32
:
922 case elfcpp::R_386_PC32
:
923 case elfcpp::R_386_16
:
924 case elfcpp::R_386_PC16
:
925 case elfcpp::R_386_8
:
926 case elfcpp::R_386_PC8
:
927 if (gsym
->is_from_dynobj()
928 || (parameters
->output_is_shared()
929 && gsym
->is_preemptible()))
931 // (a) This symbol is defined in a dynamic object. If it is a
932 // function, we make a PLT entry. Otherwise we need to
933 // either generate a COPY reloc or copy this reloc.
934 // (b) We are building a shared object and this symbol is
935 // preemptible. If it is a function, we make a PLT entry.
936 // Otherwise, we copy the reloc. We do not make COPY relocs
937 // in shared objects.
938 if (gsym
->type() == elfcpp::STT_FUNC
)
940 target
->make_plt_entry(symtab
, layout
, gsym
);
942 // If this is not a PC relative reference, then we may
943 // be taking the address of the function. In that case
944 // we need to set the entry in the dynamic symbol table
945 // to the address of the PLT entry.
946 if (r_type
!= elfcpp::R_386_PC32
947 && r_type
!= elfcpp::R_386_PC16
948 && r_type
!= elfcpp::R_386_PC8
949 && gsym
->is_from_dynobj())
950 gsym
->set_needs_dynsym_value();
952 else if (parameters
->output_is_shared())
954 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
955 rel_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
956 reloc
.get_r_offset());
959 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
965 case elfcpp::R_386_GOT32
:
967 // The symbol requires a GOT entry.
968 Output_data_got
<32, false>* got
= target
->got_section(symtab
, layout
);
969 if (got
->add_global(gsym
))
971 // If this symbol is not fully resolved, we need to add a
972 // dynamic relocation for it.
973 if (!gsym
->final_value_is_known())
975 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
976 rel_dyn
->add_global(gsym
, elfcpp::R_386_GLOB_DAT
, got
,
983 case elfcpp::R_386_PLT32
:
984 // If the symbol is fully resolved, this is just a PC32 reloc.
985 // Otherwise we need a PLT entry.
986 if (gsym
->final_value_is_known())
988 // If building a shared library, we can also skip the PLT entry
989 // if the symbol is defined in the output file and is protected
991 if (gsym
->is_defined()
992 && !gsym
->is_from_dynobj()
993 && !gsym
->is_preemptible())
995 target
->make_plt_entry(symtab
, layout
, gsym
);
998 case elfcpp::R_386_GOTOFF
:
999 case elfcpp::R_386_GOTPC
:
1000 // We need a GOT section.
1001 target
->got_section(symtab
, layout
);
1004 // These are relocations which should only be seen by the
1005 // dynamic linker, and should never be seen here.
1006 case elfcpp::R_386_COPY
:
1007 case elfcpp::R_386_GLOB_DAT
:
1008 case elfcpp::R_386_JUMP_SLOT
:
1009 case elfcpp::R_386_RELATIVE
:
1010 case elfcpp::R_386_TLS_TPOFF
:
1011 case elfcpp::R_386_TLS_DTPMOD32
:
1012 case elfcpp::R_386_TLS_DTPOFF32
:
1013 case elfcpp::R_386_TLS_TPOFF32
:
1014 case elfcpp::R_386_TLS_DESC
:
1015 gold_error(_("%s: unexpected reloc %u in object file"),
1016 object
->name().c_str(), r_type
);
1019 // These are initial tls relocs, which are expected when
1021 case elfcpp::R_386_TLS_IE
:
1022 case elfcpp::R_386_TLS_GOTIE
:
1023 case elfcpp::R_386_TLS_LE
:
1024 case elfcpp::R_386_TLS_GD
:
1025 case elfcpp::R_386_TLS_LDM
:
1026 case elfcpp::R_386_TLS_LDO_32
:
1027 case elfcpp::R_386_TLS_IE_32
:
1028 case elfcpp::R_386_TLS_LE_32
:
1029 case elfcpp::R_386_TLS_GOTDESC
:
1030 case elfcpp::R_386_TLS_DESC_CALL
:
1032 const bool is_final
= gsym
->final_value_is_known();
1033 const tls::Tls_optimization optimized_type
1034 = Target_i386::optimize_tls_reloc(is_final
, r_type
);
1037 case elfcpp::R_386_TLS_LE
:
1038 case elfcpp::R_386_TLS_LE_32
:
1039 // FIXME: If generating a shared object, we need to copy
1040 // this relocation into the object.
1041 gold_assert(!parameters
->output_is_shared());
1044 case elfcpp::R_386_TLS_IE
:
1045 case elfcpp::R_386_TLS_IE_32
:
1046 case elfcpp::R_386_TLS_GOTIE
:
1047 // FIXME: If not relaxing to LE, we need to generate a
1048 // TPOFF or TPOFF32 reloc.
1049 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1050 unsupported_reloc_global(object
, r_type
, gsym
);
1053 case elfcpp::R_386_TLS_LDM
:
1054 // FIXME: If not relaxing to LE, we need to generate a
1056 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1057 unsupported_reloc_global(object
, r_type
, gsym
);
1060 case elfcpp::R_386_TLS_LDO_32
:
1063 case elfcpp::R_386_TLS_GD
:
1064 case elfcpp::R_386_TLS_GOTDESC
:
1065 case elfcpp::R_386_TLS_DESC_CALL
:
1066 // FIXME: If not relaxing to LE, we need to generate
1067 // DTPMOD32 and DTPOFF32 relocs.
1068 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1069 unsupported_reloc_global(object
, r_type
, gsym
);
1078 case elfcpp::R_386_32PLT
:
1079 case elfcpp::R_386_TLS_GD_32
:
1080 case elfcpp::R_386_TLS_GD_PUSH
:
1081 case elfcpp::R_386_TLS_GD_CALL
:
1082 case elfcpp::R_386_TLS_GD_POP
:
1083 case elfcpp::R_386_TLS_LDM_32
:
1084 case elfcpp::R_386_TLS_LDM_PUSH
:
1085 case elfcpp::R_386_TLS_LDM_CALL
:
1086 case elfcpp::R_386_TLS_LDM_POP
:
1087 case elfcpp::R_386_USED_BY_INTEL_200
:
1089 unsupported_reloc_global(object
, r_type
, gsym
);
1094 // Scan relocations for a section.
1097 Target_i386::scan_relocs(const General_options
& options
,
1098 Symbol_table
* symtab
,
1100 Sized_relobj
<32, false>* object
,
1101 unsigned int data_shndx
,
1102 unsigned int sh_type
,
1103 const unsigned char* prelocs
,
1105 size_t local_symbol_count
,
1106 const unsigned char* plocal_symbols
,
1107 Symbol
** global_symbols
)
1109 if (sh_type
== elfcpp::SHT_RELA
)
1111 gold_error(_("%s: unsupported RELA reloc section"),
1112 object
->name().c_str());
1116 gold::scan_relocs
<32, false, Target_i386
, elfcpp::SHT_REL
,
1131 // Finalize the sections.
1134 Target_i386::do_finalize_sections(Layout
* layout
)
1136 // Fill in some more dynamic tags.
1137 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1140 if (this->got_plt_
!= NULL
)
1141 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1143 if (this->plt_
!= NULL
)
1145 const Output_data
* od
= this->plt_
->rel_plt();
1146 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1147 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1148 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_REL
);
1151 if (this->rel_dyn_
!= NULL
)
1153 const Output_data
* od
= this->rel_dyn_
;
1154 odyn
->add_section_address(elfcpp::DT_REL
, od
);
1155 odyn
->add_section_size(elfcpp::DT_RELSZ
, od
);
1156 odyn
->add_constant(elfcpp::DT_RELENT
,
1157 elfcpp::Elf_sizes
<32>::rel_size
);
1160 if (!parameters
->output_is_shared())
1162 // The value of the DT_DEBUG tag is filled in by the dynamic
1163 // linker at run time, and used by the debugger.
1164 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1168 // Emit any relocs we saved in an attempt to avoid generating COPY
1170 if (this->copy_relocs_
== NULL
)
1172 if (this->copy_relocs_
->any_to_emit())
1174 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
1175 this->copy_relocs_
->emit(rel_dyn
);
1177 delete this->copy_relocs_
;
1178 this->copy_relocs_
= NULL
;
1181 // Perform a relocation.
1184 Target_i386::Relocate::relocate(const Relocate_info
<32, false>* relinfo
,
1185 Target_i386
* target
,
1187 const elfcpp::Rel
<32, false>& rel
,
1188 unsigned int r_type
,
1189 const Sized_symbol
<32>* gsym
,
1190 const Symbol_value
<32>* psymval
,
1191 unsigned char* view
,
1192 elfcpp::Elf_types
<32>::Elf_Addr address
,
1195 if (this->skip_call_tls_get_addr_
)
1197 if (r_type
!= elfcpp::R_386_PLT32
1199 || strcmp(gsym
->name(), "___tls_get_addr") != 0)
1200 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1201 _("missing expected TLS relocation"));
1204 this->skip_call_tls_get_addr_
= false;
1209 // Pick the value to use for symbols defined in shared objects.
1210 Symbol_value
<32> symval
;
1212 && (gsym
->is_from_dynobj()
1213 || (parameters
->output_is_shared()
1214 && gsym
->is_preemptible()))
1215 && gsym
->has_plt_offset())
1217 symval
.set_output_value(target
->plt_section()->address()
1218 + gsym
->plt_offset());
1222 const Sized_relobj
<32, false>* object
= relinfo
->object
;
1224 // Get the GOT offset if needed.
1225 bool have_got_offset
= false;
1226 unsigned int got_offset
= 0;
1229 case elfcpp::R_386_GOT32
:
1232 gold_assert(gsym
->has_got_offset());
1233 got_offset
= gsym
->got_offset();
1237 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(rel
.get_r_info());
1238 got_offset
= object
->local_got_offset(r_sym
);
1240 have_got_offset
= true;
1249 case elfcpp::R_386_NONE
:
1250 case elfcpp::R_386_GNU_VTINHERIT
:
1251 case elfcpp::R_386_GNU_VTENTRY
:
1254 case elfcpp::R_386_32
:
1255 Relocate_functions
<32, false>::rel32(view
, object
, psymval
);
1258 case elfcpp::R_386_PC32
:
1259 Relocate_functions
<32, false>::pcrel32(view
, object
, psymval
, address
);
1262 case elfcpp::R_386_16
:
1263 Relocate_functions
<32, false>::rel16(view
, object
, psymval
);
1266 case elfcpp::R_386_PC16
:
1267 Relocate_functions
<32, false>::pcrel16(view
, object
, psymval
, address
);
1270 case elfcpp::R_386_8
:
1271 Relocate_functions
<32, false>::rel8(view
, object
, psymval
);
1274 case elfcpp::R_386_PC8
:
1275 Relocate_functions
<32, false>::pcrel8(view
, object
, psymval
, address
);
1278 case elfcpp::R_386_PLT32
:
1279 gold_assert(gsym
->has_plt_offset()
1280 || gsym
->final_value_is_known());
1281 Relocate_functions
<32, false>::pcrel32(view
, object
, psymval
, address
);
1284 case elfcpp::R_386_GOT32
:
1285 gold_assert(have_got_offset
);
1286 Relocate_functions
<32, false>::rel32(view
, got_offset
);
1289 case elfcpp::R_386_GOTOFF
:
1291 elfcpp::Elf_types
<32>::Elf_Addr value
;
1292 value
= (psymval
->value(object
, 0)
1293 - target
->got_section(NULL
, NULL
)->address());
1294 Relocate_functions
<32, false>::rel32(view
, value
);
1298 case elfcpp::R_386_GOTPC
:
1300 elfcpp::Elf_types
<32>::Elf_Addr value
;
1301 value
= target
->got_section(NULL
, NULL
)->address();
1302 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1306 case elfcpp::R_386_COPY
:
1307 case elfcpp::R_386_GLOB_DAT
:
1308 case elfcpp::R_386_JUMP_SLOT
:
1309 case elfcpp::R_386_RELATIVE
:
1310 // These are outstanding tls relocs, which are unexpected when
1312 case elfcpp::R_386_TLS_TPOFF
:
1313 case elfcpp::R_386_TLS_DTPMOD32
:
1314 case elfcpp::R_386_TLS_DTPOFF32
:
1315 case elfcpp::R_386_TLS_TPOFF32
:
1316 case elfcpp::R_386_TLS_DESC
:
1317 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1318 _("unexpected reloc %u in object file"),
1322 // These are initial tls relocs, which are expected when
1324 case elfcpp::R_386_TLS_IE
:
1325 case elfcpp::R_386_TLS_GOTIE
:
1326 case elfcpp::R_386_TLS_LE
:
1327 case elfcpp::R_386_TLS_GD
:
1328 case elfcpp::R_386_TLS_LDM
:
1329 case elfcpp::R_386_TLS_LDO_32
:
1330 case elfcpp::R_386_TLS_IE_32
:
1331 case elfcpp::R_386_TLS_LE_32
:
1332 case elfcpp::R_386_TLS_GOTDESC
:
1333 case elfcpp::R_386_TLS_DESC_CALL
:
1334 this->relocate_tls(relinfo
, relnum
, rel
, r_type
, gsym
, psymval
, view
,
1335 address
, view_size
);
1338 case elfcpp::R_386_32PLT
:
1339 case elfcpp::R_386_TLS_GD_32
:
1340 case elfcpp::R_386_TLS_GD_PUSH
:
1341 case elfcpp::R_386_TLS_GD_CALL
:
1342 case elfcpp::R_386_TLS_GD_POP
:
1343 case elfcpp::R_386_TLS_LDM_32
:
1344 case elfcpp::R_386_TLS_LDM_PUSH
:
1345 case elfcpp::R_386_TLS_LDM_CALL
:
1346 case elfcpp::R_386_TLS_LDM_POP
:
1347 case elfcpp::R_386_USED_BY_INTEL_200
:
1349 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1350 _("unsupported reloc %u"),
1358 // Perform a TLS relocation.
1361 Target_i386::Relocate::relocate_tls(const Relocate_info
<32, false>* relinfo
,
1363 const elfcpp::Rel
<32, false>& rel
,
1364 unsigned int r_type
,
1365 const Sized_symbol
<32>* gsym
,
1366 const Symbol_value
<32>* psymval
,
1367 unsigned char* view
,
1368 elfcpp::Elf_types
<32>::Elf_Addr
,
1371 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1372 if (tls_segment
== NULL
)
1374 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1375 _("TLS reloc but no TLS segment"));
1379 elfcpp::Elf_types
<32>::Elf_Addr value
= psymval
->value(relinfo
->object
, 0);
1381 const bool is_final
= (gsym
== NULL
1382 ? !parameters
->output_is_position_independent()
1383 : gsym
->final_value_is_known());
1384 const tls::Tls_optimization optimized_type
1385 = Target_i386::optimize_tls_reloc(is_final
, r_type
);
1388 case elfcpp::R_386_TLS_LE_32
:
1389 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1390 Relocate_functions
<32, false>::rel32(view
, value
);
1393 case elfcpp::R_386_TLS_LE
:
1394 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1395 Relocate_functions
<32, false>::rel32(view
, value
);
1398 case elfcpp::R_386_TLS_IE
:
1399 case elfcpp::R_386_TLS_GOTIE
:
1400 case elfcpp::R_386_TLS_IE_32
:
1401 if (optimized_type
== tls::TLSOPT_TO_LE
)
1403 Target_i386::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1404 rel
, r_type
, value
, view
,
1408 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1409 _("unsupported reloc %u"),
1413 case elfcpp::R_386_TLS_GD
:
1414 if (optimized_type
== tls::TLSOPT_TO_LE
)
1416 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1417 rel
, r_type
, value
, view
,
1421 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1422 _("unsupported reloc %u"),
1426 case elfcpp::R_386_TLS_LDM
:
1427 if (this->local_dynamic_type_
== LOCAL_DYNAMIC_SUN
)
1429 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1430 _("both SUN and GNU model "
1431 "TLS relocations"));
1434 this->local_dynamic_type_
= LOCAL_DYNAMIC_GNU
;
1435 if (optimized_type
== tls::TLSOPT_TO_LE
)
1437 this->tls_ld_to_le(relinfo
, relnum
, tls_segment
, rel
, r_type
,
1438 value
, view
, view_size
);
1441 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1442 _("unsupported reloc %u"),
1446 case elfcpp::R_386_TLS_LDO_32
:
1447 // This reloc can appear in debugging sections, in which case we
1448 // won't see the TLS_LDM reloc. The local_dynamic_type field
1450 if (optimized_type
!= tls::TLSOPT_TO_LE
1451 || this->local_dynamic_type_
== LOCAL_DYNAMIC_NONE
)
1452 value
= value
- tls_segment
->vaddr();
1453 else if (this->local_dynamic_type_
== LOCAL_DYNAMIC_GNU
)
1454 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1456 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1457 Relocate_functions
<32, false>::rel32(view
, value
);
1460 case elfcpp::R_386_TLS_GOTDESC
:
1461 case elfcpp::R_386_TLS_DESC_CALL
:
1462 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1463 _("unsupported reloc %u"),
1469 // Do a relocation in which we convert a TLS Initial-Exec to a
1473 Target_i386::Relocate::tls_ie_to_le(const Relocate_info
<32, false>* relinfo
,
1475 Output_segment
* tls_segment
,
1476 const elfcpp::Rel
<32, false>& rel
,
1477 unsigned int r_type
,
1478 elfcpp::Elf_types
<32>::Elf_Addr value
,
1479 unsigned char* view
,
1482 // We have to actually change the instructions, which means that we
1483 // need to examine the opcodes to figure out which instruction we
1485 if (r_type
== elfcpp::R_386_TLS_IE
)
1487 // movl %gs:XX,%eax ==> movl $YY,%eax
1488 // movl %gs:XX,%reg ==> movl $YY,%reg
1489 // addl %gs:XX,%reg ==> addl $YY,%reg
1490 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -1);
1491 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 4);
1493 unsigned char op1
= view
[-1];
1496 // movl XX,%eax ==> movl $YY,%eax
1501 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1503 unsigned char op2
= view
[-2];
1506 // movl XX,%reg ==> movl $YY,%reg
1507 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1508 (op1
& 0xc7) == 0x05);
1510 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1512 else if (op2
== 0x03)
1514 // addl XX,%reg ==> addl $YY,%reg
1515 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1516 (op1
& 0xc7) == 0x05);
1518 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1521 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), 0);
1526 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1527 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1528 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1529 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1530 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 4);
1532 unsigned char op1
= view
[-1];
1533 unsigned char op2
= view
[-2];
1534 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1535 (op1
& 0xc0) == 0x80 && (op1
& 7) != 4);
1538 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1540 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1542 else if (op2
== 0x2b)
1544 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1546 view
[-1] = 0xe8 | ((op1
>> 3) & 7);
1548 else if (op2
== 0x03)
1550 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1552 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1555 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), 0);
1558 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1559 if (r_type
== elfcpp::R_386_TLS_IE
|| r_type
== elfcpp::R_386_TLS_GOTIE
)
1562 Relocate_functions
<32, false>::rel32(view
, value
);
1565 // Do a relocation in which we convert a TLS General-Dynamic to a
1569 Target_i386::Relocate::tls_gd_to_le(const Relocate_info
<32, false>* relinfo
,
1571 Output_segment
* tls_segment
,
1572 const elfcpp::Rel
<32, false>& rel
,
1574 elfcpp::Elf_types
<32>::Elf_Addr value
,
1575 unsigned char* view
,
1578 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1579 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1580 // leal foo(%reg),%eax; call ___tls_get_addr
1581 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1583 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1584 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 9);
1586 unsigned char op1
= view
[-1];
1587 unsigned char op2
= view
[-2];
1589 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1590 op2
== 0x8d || op2
== 0x04);
1591 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), view
[4] == 0xe8);
1597 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -3);
1598 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), view
[-3] == 0x8d);
1599 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1600 ((op1
& 0xc7) == 0x05 && op1
!= (4 << 3)));
1601 memcpy(view
- 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1605 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1606 (op1
& 0xf8) == 0x80 && (op1
& 7) != 4);
1607 if (static_cast<off_t
>(rel
.get_r_offset() + 9) < view_size
1610 // There is a trailing nop. Use the size byte subl.
1611 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1616 // Use the five byte subl.
1617 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1621 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1622 Relocate_functions
<32, false>::rel32(view
+ roff
, value
);
1624 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1626 this->skip_call_tls_get_addr_
= true;
1629 // Do a relocation in which we convert a TLS Local-Dynamic to a
1633 Target_i386::Relocate::tls_ld_to_le(const Relocate_info
<32, false>* relinfo
,
1636 const elfcpp::Rel
<32, false>& rel
,
1638 elfcpp::Elf_types
<32>::Elf_Addr
,
1639 unsigned char* view
,
1642 // leal foo(%reg), %eax; call ___tls_get_addr
1643 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1645 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1646 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 9);
1648 // FIXME: Does this test really always pass?
1649 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1650 view
[-2] == 0x8d && view
[-1] == 0x83);
1652 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), view
[4] == 0xe8);
1654 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1656 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1658 this->skip_call_tls_get_addr_
= true;
1661 // Relocate section data.
1664 Target_i386::relocate_section(const Relocate_info
<32, false>* relinfo
,
1665 unsigned int sh_type
,
1666 const unsigned char* prelocs
,
1668 unsigned char* view
,
1669 elfcpp::Elf_types
<32>::Elf_Addr address
,
1672 gold_assert(sh_type
== elfcpp::SHT_REL
);
1674 gold::relocate_section
<32, false, Target_i386
, elfcpp::SHT_REL
,
1675 Target_i386::Relocate
>(
1685 // Return the value to use for a dynamic which requires special
1686 // treatment. This is how we support equality comparisons of function
1687 // pointers across shared library boundaries, as described in the
1688 // processor specific ABI supplement.
1691 Target_i386::do_dynsym_value(const Symbol
* gsym
) const
1693 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1694 return this->plt_section()->address() + gsym
->plt_offset();
1697 // Return a string used to fill a code section with nops to take up
1698 // the specified length.
1701 Target_i386::do_code_fill(off_t length
)
1705 // Build a jmp instruction to skip over the bytes.
1706 unsigned char jmp
[5];
1708 elfcpp::Swap_unaligned
<32, false>::writeval(jmp
+ 1, length
- 5);
1709 return (std::string(reinterpret_cast<char*>(&jmp
[0]), 5)
1710 + std::string(length
- 5, '\0'));
1713 // Nop sequences of various lengths.
1714 const char nop1
[1] = { 0x90 }; // nop
1715 const char nop2
[2] = { 0x66, 0x90 }; // xchg %ax %ax
1716 const char nop3
[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1717 const char nop4
[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1718 const char nop5
[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1719 0x00 }; // leal 0(%esi,1),%esi
1720 const char nop6
[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1722 const char nop7
[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1724 const char nop8
[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1725 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1726 const char nop9
[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1727 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1729 const char nop10
[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1730 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1732 const char nop11
[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1733 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1735 const char nop12
[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1736 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1737 0x00, 0x00, 0x00, 0x00 };
1738 const char nop13
[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1739 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1740 0x27, 0x00, 0x00, 0x00,
1742 const char nop14
[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1743 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1744 0xbc, 0x27, 0x00, 0x00,
1746 const char nop15
[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1747 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1748 0x90, 0x90, 0x90, 0x90,
1751 const char* nops
[16] = {
1753 nop1
, nop2
, nop3
, nop4
, nop5
, nop6
, nop7
,
1754 nop8
, nop9
, nop10
, nop11
, nop12
, nop13
, nop14
, nop15
1757 return std::string(nops
[length
], length
);
1760 // The selector for i386 object files.
1762 class Target_selector_i386
: public Target_selector
1765 Target_selector_i386()
1766 : Target_selector(elfcpp::EM_386
, 32, false)
1770 recognize(int machine
, int osabi
, int abiversion
);
1773 Target_i386
* target_
;
1776 // Recognize an i386 object file when we already know that the machine
1777 // number is EM_386.
1780 Target_selector_i386::recognize(int, int, int)
1782 if (this->target_
== NULL
)
1783 this->target_
= new Target_i386();
1784 return this->target_
;
1787 Target_selector_i386 target_selector_i386
;
1789 } // End anonymous namespace.