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 Output_section
* output_section
,
74 bool needs_special_offset_handling
,
75 size_t local_symbol_count
,
76 const unsigned char* plocal_symbols
);
78 // Finalize the sections.
80 do_finalize_sections(Layout
*);
82 // Return the value to use for a dynamic which requires special
85 do_dynsym_value(const Symbol
*) const;
87 // Relocate a section.
89 relocate_section(const Relocate_info
<32, false>*,
91 const unsigned char* prelocs
,
93 Output_section
* output_section
,
94 bool needs_special_offset_handling
,
96 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
99 // Return a string used to fill a code section with nops.
101 do_code_fill(off_t length
);
103 // Return the size of the GOT section.
107 gold_assert(this->got_
!= NULL
);
108 return this->got_
->data_size();
112 // The class which scans relocations.
116 local(const General_options
& options
, Symbol_table
* symtab
,
117 Layout
* layout
, Target_i386
* target
,
118 Sized_relobj
<32, false>* object
,
119 unsigned int data_shndx
,
120 const elfcpp::Rel
<32, false>& reloc
, unsigned int r_type
,
121 const elfcpp::Sym
<32, false>& lsym
);
124 global(const General_options
& options
, Symbol_table
* symtab
,
125 Layout
* layout
, Target_i386
* target
,
126 Sized_relobj
<32, false>* object
,
127 unsigned int data_shndx
,
128 const elfcpp::Rel
<32, false>& reloc
, unsigned int r_type
,
132 unsupported_reloc_local(Sized_relobj
<32, false>*, unsigned int r_type
);
135 unsupported_reloc_global(Sized_relobj
<32, false>*, unsigned int r_type
,
139 // The class which implements relocation.
144 : skip_call_tls_get_addr_(false),
145 local_dynamic_type_(LOCAL_DYNAMIC_NONE
)
150 if (this->skip_call_tls_get_addr_
)
152 // FIXME: This needs to specify the location somehow.
153 gold_error(_("missing expected TLS relocation"));
157 // Return whether the static relocation needs to be applied.
159 should_apply_static_reloc(const Sized_symbol
<32>* gsym
,
160 bool is_absolute_ref
,
161 bool is_function_call
,
164 // Do a relocation. Return false if the caller should not issue
165 // any warnings about this relocation.
167 relocate(const Relocate_info
<32, false>*, Target_i386
*, size_t relnum
,
168 const elfcpp::Rel
<32, false>&,
169 unsigned int r_type
, const Sized_symbol
<32>*,
170 const Symbol_value
<32>*,
171 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
,
175 // Do a TLS relocation.
177 relocate_tls(const Relocate_info
<32, false>*, size_t relnum
,
178 const elfcpp::Rel
<32, false>&,
179 unsigned int r_type
, const Sized_symbol
<32>*,
180 const Symbol_value
<32>*,
181 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
, off_t
);
183 // Do a TLS General-Dynamic to Local-Exec transition.
185 tls_gd_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 // Do a TLS Local-Dynamic to Local-Exec transition.
194 tls_ld_to_le(const Relocate_info
<32, false>*, size_t relnum
,
195 Output_segment
* tls_segment
,
196 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
197 elfcpp::Elf_types
<32>::Elf_Addr value
,
201 // Do a TLS Initial-Exec to Local-Exec transition.
203 tls_ie_to_le(const Relocate_info
<32, false>*, size_t relnum
,
204 Output_segment
* tls_segment
,
205 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
206 elfcpp::Elf_types
<32>::Elf_Addr value
,
210 // We need to keep track of which type of local dynamic relocation
211 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
212 enum Local_dynamic_type
219 // This is set if we should skip the next reloc, which should be a
220 // PLT32 reloc against ___tls_get_addr.
221 bool skip_call_tls_get_addr_
;
222 // The type of local dynamic relocation we have seen in the section
223 // being relocated, if any.
224 Local_dynamic_type local_dynamic_type_
;
227 // Adjust TLS relocation type based on the options and whether this
228 // is a local symbol.
229 static tls::Tls_optimization
230 optimize_tls_reloc(bool is_final
, int r_type
);
232 // Get the GOT section, creating it if necessary.
233 Output_data_got
<32, false>*
234 got_section(Symbol_table
*, Layout
*);
236 // Get the GOT PLT section.
238 got_plt_section() const
240 gold_assert(this->got_plt_
!= NULL
);
241 return this->got_plt_
;
244 // Create a PLT entry for a global symbol.
246 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
248 // Get the PLT section.
249 const Output_data_plt_i386
*
252 gold_assert(this->plt_
!= NULL
);
256 // Get the dynamic reloc section, creating it if necessary.
258 rel_dyn_section(Layout
*);
260 // Return true if the symbol may need a COPY relocation.
261 // References from an executable object to non-function symbols
262 // defined in a dynamic object may need a COPY relocation.
264 may_need_copy_reloc(Symbol
* gsym
)
266 return (!parameters
->output_is_shared()
267 && gsym
->is_from_dynobj()
268 && gsym
->type() != elfcpp::STT_FUNC
);
271 // Copy a relocation against a global symbol.
273 copy_reloc(const General_options
*, Symbol_table
*, Layout
*,
274 Sized_relobj
<32, false>*, unsigned int,
275 Symbol
*, const elfcpp::Rel
<32, false>&);
277 // Information about this specific target which we pass to the
278 // general Target structure.
279 static const Target::Target_info i386_info
;
282 Output_data_got
<32, false>* got_
;
284 Output_data_plt_i386
* plt_
;
285 // The GOT PLT section.
286 Output_data_space
* got_plt_
;
287 // The dynamic reloc section.
288 Reloc_section
* rel_dyn_
;
289 // Relocs saved to avoid a COPY reloc.
290 Copy_relocs
<32, false>* copy_relocs_
;
291 // Space for variables copied with a COPY reloc.
292 Output_data_space
* dynbss_
;
295 const Target::Target_info
Target_i386::i386_info
=
298 false, // is_big_endian
299 elfcpp::EM_386
, // machine_code
300 false, // has_make_symbol
301 false, // has_resolve
302 true, // has_code_fill
303 true, // is_default_stack_executable
304 "/usr/lib/libc.so.1", // dynamic_linker
305 0x08048000, // default_text_segment_address
306 0x1000, // abi_pagesize
307 0x1000 // common_pagesize
310 // Get the GOT section, creating it if necessary.
312 Output_data_got
<32, false>*
313 Target_i386::got_section(Symbol_table
* symtab
, Layout
* layout
)
315 if (this->got_
== NULL
)
317 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
319 this->got_
= new Output_data_got
<32, false>();
321 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
322 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
325 // The old GNU linker creates a .got.plt section. We just
326 // create another set of data in the .got section. Note that we
327 // always create a PLT if we create a GOT, although the PLT
329 this->got_plt_
= new Output_data_space(4);
330 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
331 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
334 // The first three entries are reserved.
335 this->got_plt_
->set_space_size(3 * 4);
337 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
338 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL
,
340 0, 0, elfcpp::STT_OBJECT
,
342 elfcpp::STV_HIDDEN
, 0,
349 // Get the dynamic reloc section, creating it if necessary.
351 Target_i386::Reloc_section
*
352 Target_i386::rel_dyn_section(Layout
* layout
)
354 if (this->rel_dyn_
== NULL
)
356 gold_assert(layout
!= NULL
);
357 this->rel_dyn_
= new Reloc_section();
358 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
359 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
361 return this->rel_dyn_
;
364 // A class to handle the PLT data.
366 class Output_data_plt_i386
: public Output_section_data
369 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, false> Reloc_section
;
371 Output_data_plt_i386(Layout
*, Output_data_space
*);
373 // Add an entry to the PLT.
375 add_entry(Symbol
* gsym
);
377 // Return the .rel.plt section data.
380 { return this->rel_
; }
384 do_adjust_output_section(Output_section
* os
);
387 // The size of an entry in the PLT.
388 static const int plt_entry_size
= 16;
390 // The first entry in the PLT for an executable.
391 static unsigned char exec_first_plt_entry
[plt_entry_size
];
393 // The first entry in the PLT for a shared object.
394 static unsigned char dyn_first_plt_entry
[plt_entry_size
];
396 // Other entries in the PLT for an executable.
397 static unsigned char exec_plt_entry
[plt_entry_size
];
399 // Other entries in the PLT for a shared object.
400 static unsigned char dyn_plt_entry
[plt_entry_size
];
402 // Set the final size.
404 do_set_address(uint64_t, off_t
)
405 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
407 // Write out the PLT data.
409 do_write(Output_file
*);
411 // The reloc section.
413 // The .got.plt section.
414 Output_data_space
* got_plt_
;
415 // The number of PLT entries.
419 // Create the PLT section. The ordinary .got section is an argument,
420 // since we need to refer to the start. We also create our own .got
421 // section just for PLT entries.
423 Output_data_plt_i386::Output_data_plt_i386(Layout
* layout
,
424 Output_data_space
* got_plt
)
425 : Output_section_data(4), got_plt_(got_plt
), count_(0)
427 this->rel_
= new Reloc_section();
428 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
429 elfcpp::SHF_ALLOC
, this->rel_
);
433 Output_data_plt_i386::do_adjust_output_section(Output_section
* os
)
435 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
436 // linker, and so do we.
440 // Add an entry to the PLT.
443 Output_data_plt_i386::add_entry(Symbol
* gsym
)
445 gold_assert(!gsym
->has_plt_offset());
447 // Note that when setting the PLT offset we skip the initial
448 // reserved PLT entry.
449 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
453 off_t got_offset
= this->got_plt_
->data_size();
455 // Every PLT entry needs a GOT entry which points back to the PLT
456 // entry (this will be changed by the dynamic linker, normally
457 // lazily when the function is called).
458 this->got_plt_
->set_space_size(got_offset
+ 4);
460 // Every PLT entry needs a reloc.
461 gsym
->set_needs_dynsym_entry();
462 this->rel_
->add_global(gsym
, elfcpp::R_386_JUMP_SLOT
, this->got_plt_
,
465 // Note that we don't need to save the symbol. The contents of the
466 // PLT are independent of which symbols are used. The symbols only
467 // appear in the relocations.
470 // The first entry in the PLT for an executable.
472 unsigned char Output_data_plt_i386::exec_first_plt_entry
[plt_entry_size
] =
474 0xff, 0x35, // pushl contents of memory address
475 0, 0, 0, 0, // replaced with address of .got + 4
476 0xff, 0x25, // jmp indirect
477 0, 0, 0, 0, // replaced with address of .got + 8
481 // The first entry in the PLT for a shared object.
483 unsigned char Output_data_plt_i386::dyn_first_plt_entry
[plt_entry_size
] =
485 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
486 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
490 // Subsequent entries in the PLT for an executable.
492 unsigned char Output_data_plt_i386::exec_plt_entry
[plt_entry_size
] =
494 0xff, 0x25, // jmp indirect
495 0, 0, 0, 0, // replaced with address of symbol in .got
496 0x68, // pushl immediate
497 0, 0, 0, 0, // replaced with offset into relocation table
498 0xe9, // jmp relative
499 0, 0, 0, 0 // replaced with offset to start of .plt
502 // Subsequent entries in the PLT for a shared object.
504 unsigned char Output_data_plt_i386::dyn_plt_entry
[plt_entry_size
] =
506 0xff, 0xa3, // jmp *offset(%ebx)
507 0, 0, 0, 0, // replaced with offset of symbol in .got
508 0x68, // pushl immediate
509 0, 0, 0, 0, // replaced with offset into relocation table
510 0xe9, // jmp relative
511 0, 0, 0, 0 // replaced with offset to start of .plt
514 // Write out the PLT. This uses the hand-coded instructions above,
515 // and adjusts them as needed. This is all specified by the i386 ELF
516 // Processor Supplement.
519 Output_data_plt_i386::do_write(Output_file
* of
)
521 const off_t offset
= this->offset();
522 const off_t oview_size
= this->data_size();
523 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
525 const off_t got_file_offset
= this->got_plt_
->offset();
526 const off_t got_size
= this->got_plt_
->data_size();
527 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
530 unsigned char* pov
= oview
;
532 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
533 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
535 if (parameters
->output_is_shared())
536 memcpy(pov
, dyn_first_plt_entry
, plt_entry_size
);
539 memcpy(pov
, exec_first_plt_entry
, plt_entry_size
);
540 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 4);
541 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 8);
543 pov
+= plt_entry_size
;
545 unsigned char* got_pov
= got_view
;
547 memset(got_pov
, 0, 12);
550 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
552 unsigned int plt_offset
= plt_entry_size
;
553 unsigned int plt_rel_offset
= 0;
554 unsigned int got_offset
= 12;
555 const unsigned int count
= this->count_
;
556 for (unsigned int i
= 0;
559 pov
+= plt_entry_size
,
561 plt_offset
+= plt_entry_size
,
562 plt_rel_offset
+= rel_size
,
565 // Set and adjust the PLT entry itself.
567 if (parameters
->output_is_shared())
569 memcpy(pov
, dyn_plt_entry
, plt_entry_size
);
570 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_offset
);
574 memcpy(pov
, exec_plt_entry
, plt_entry_size
);
575 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
580 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_rel_offset
);
581 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
582 - (plt_offset
+ plt_entry_size
));
584 // Set the entry in the GOT.
585 elfcpp::Swap
<32, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
588 gold_assert(pov
- oview
== oview_size
);
589 gold_assert(got_pov
- got_view
== got_size
);
591 of
->write_output_view(offset
, oview_size
, oview
);
592 of
->write_output_view(got_file_offset
, got_size
, got_view
);
595 // Create a PLT entry for a global symbol.
598 Target_i386::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
, Symbol
* gsym
)
600 if (gsym
->has_plt_offset())
603 if (this->plt_
== NULL
)
605 // Create the GOT sections first.
606 this->got_section(symtab
, layout
);
608 this->plt_
= new Output_data_plt_i386(layout
, this->got_plt_
);
609 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
611 | elfcpp::SHF_EXECINSTR
),
615 this->plt_
->add_entry(gsym
);
618 // Handle a relocation against a non-function symbol defined in a
619 // dynamic object. The traditional way to handle this is to generate
620 // a COPY relocation to copy the variable at runtime from the shared
621 // object into the executable's data segment. However, this is
622 // undesirable in general, as if the size of the object changes in the
623 // dynamic object, the executable will no longer work correctly. If
624 // this relocation is in a writable section, then we can create a
625 // dynamic reloc and the dynamic linker will resolve it to the correct
626 // address at runtime. However, we do not want do that if the
627 // relocation is in a read-only section, as it would prevent the
628 // readonly segment from being shared. And if we have to eventually
629 // generate a COPY reloc, then any dynamic relocations will be
630 // useless. So this means that if this is a writable section, we need
631 // to save the relocation until we see whether we have to create a
632 // COPY relocation for this symbol for any other relocation.
635 Target_i386::copy_reloc(const General_options
* options
,
636 Symbol_table
* symtab
,
638 Sized_relobj
<32, false>* object
,
639 unsigned int data_shndx
, Symbol
* gsym
,
640 const elfcpp::Rel
<32, false>& rel
)
642 Sized_symbol
<32>* ssym
;
643 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(32) (gsym
646 if (!Copy_relocs
<32, false>::need_copy_reloc(options
, object
,
649 // So far we do not need a COPY reloc. Save this relocation.
650 // If it turns out that we never need a COPY reloc for this
651 // symbol, then we will emit the relocation.
652 if (this->copy_relocs_
== NULL
)
653 this->copy_relocs_
= new Copy_relocs
<32, false>();
654 this->copy_relocs_
->save(ssym
, object
, data_shndx
, rel
);
658 // Allocate space for this symbol in the .bss section.
660 elfcpp::Elf_types
<32>::Elf_WXword symsize
= ssym
->symsize();
662 // There is no defined way to determine the required alignment
663 // of the symbol. We pick the alignment based on the size. We
664 // set an arbitrary maximum of 256.
666 for (align
= 1; align
< 512; align
<<= 1)
667 if ((symsize
& align
) != 0)
670 if (this->dynbss_
== NULL
)
672 this->dynbss_
= new Output_data_space(align
);
673 layout
->add_output_section_data(".bss",
676 | elfcpp::SHF_WRITE
),
680 Output_data_space
* dynbss
= this->dynbss_
;
682 if (align
> dynbss
->addralign())
683 dynbss
->set_space_alignment(align
);
685 off_t dynbss_size
= dynbss
->data_size();
686 dynbss_size
= align_address(dynbss_size
, align
);
687 off_t offset
= dynbss_size
;
688 dynbss
->set_space_size(dynbss_size
+ symsize
);
690 symtab
->define_with_copy_reloc(this, ssym
, dynbss
, offset
);
692 // Add the COPY reloc.
693 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
694 rel_dyn
->add_global(ssym
, elfcpp::R_386_COPY
, dynbss
, offset
);
698 // Optimize the TLS relocation type based on what we know about the
699 // symbol. IS_FINAL is true if the final address of this symbol is
700 // known at link time.
702 tls::Tls_optimization
703 Target_i386::optimize_tls_reloc(bool is_final
, int r_type
)
705 // If we are generating a shared library, then we can't do anything
707 if (parameters
->output_is_shared())
708 return tls::TLSOPT_NONE
;
712 case elfcpp::R_386_TLS_GD
:
713 case elfcpp::R_386_TLS_GOTDESC
:
714 case elfcpp::R_386_TLS_DESC_CALL
:
715 // These are General-Dynamic which permits fully general TLS
716 // access. Since we know that we are generating an executable,
717 // we can convert this to Initial-Exec. If we also know that
718 // this is a local symbol, we can further switch to Local-Exec.
720 return tls::TLSOPT_TO_LE
;
721 return tls::TLSOPT_TO_IE
;
723 case elfcpp::R_386_TLS_LDM
:
724 // This is Local-Dynamic, which refers to a local symbol in the
725 // dynamic TLS block. Since we know that we generating an
726 // executable, we can switch to Local-Exec.
727 return tls::TLSOPT_TO_LE
;
729 case elfcpp::R_386_TLS_LDO_32
:
730 // Another type of Local-Dynamic relocation.
731 return tls::TLSOPT_TO_LE
;
733 case elfcpp::R_386_TLS_IE
:
734 case elfcpp::R_386_TLS_GOTIE
:
735 case elfcpp::R_386_TLS_IE_32
:
736 // These are Initial-Exec relocs which get the thread offset
737 // from the GOT. If we know that we are linking against the
738 // local symbol, we can switch to Local-Exec, which links the
739 // thread offset into the instruction.
741 return tls::TLSOPT_TO_LE
;
742 return tls::TLSOPT_NONE
;
744 case elfcpp::R_386_TLS_LE
:
745 case elfcpp::R_386_TLS_LE_32
:
746 // When we already have Local-Exec, there is nothing further we
748 return tls::TLSOPT_NONE
;
755 // Report an unsupported relocation against a local symbol.
758 Target_i386::Scan::unsupported_reloc_local(Sized_relobj
<32, false>* object
,
761 gold_error(_("%s: unsupported reloc %u against local symbol"),
762 object
->name().c_str(), r_type
);
765 // Scan a relocation for a local symbol.
768 Target_i386::Scan::local(const General_options
&,
769 Symbol_table
* symtab
,
772 Sized_relobj
<32, false>* object
,
773 unsigned int data_shndx
,
774 const elfcpp::Rel
<32, false>& reloc
,
776 const elfcpp::Sym
<32, false>&)
780 case elfcpp::R_386_NONE
:
781 case elfcpp::R_386_GNU_VTINHERIT
:
782 case elfcpp::R_386_GNU_VTENTRY
:
785 case elfcpp::R_386_32
:
786 // If building a shared library (or a position-independent
787 // executable), we need to create a dynamic relocation for
788 // this location. The relocation applied at link time will
789 // apply the link-time value, so we flag the location with
790 // an R_386_RELATIVE relocation so the dynamic loader can
791 // relocate it easily.
792 if (parameters
->output_is_position_independent())
794 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
795 rel_dyn
->add_local(object
, 0, elfcpp::R_386_RELATIVE
, data_shndx
,
796 reloc
.get_r_offset());
800 case elfcpp::R_386_16
:
801 case elfcpp::R_386_8
:
802 // If building a shared library (or a position-independent
803 // executable), we need to create a dynamic relocation for
804 // this location. Because the addend needs to remain in the
805 // data section, we need to be careful not to apply this
806 // relocation statically.
807 if (parameters
->output_is_position_independent())
809 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
810 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
811 rel_dyn
->add_local(object
, r_sym
, r_type
, data_shndx
,
812 reloc
.get_r_offset());
816 case elfcpp::R_386_PC32
:
817 case elfcpp::R_386_PC16
:
818 case elfcpp::R_386_PC8
:
821 case elfcpp::R_386_PLT32
:
822 // Since we know this is a local symbol, we can handle this as a
826 case elfcpp::R_386_GOTOFF
:
827 case elfcpp::R_386_GOTPC
:
828 // We need a GOT section.
829 target
->got_section(symtab
, layout
);
832 case elfcpp::R_386_GOT32
:
834 // The symbol requires a GOT entry.
835 Output_data_got
<32, false>* got
= target
->got_section(symtab
, layout
);
836 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
837 if (got
->add_local(object
, r_sym
))
839 // If we are generating a shared object, we need to add a
840 // dynamic RELATIVE relocation for this symbol.
841 if (parameters
->output_is_position_independent())
843 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
844 rel_dyn
->add_local(object
, 0, elfcpp::R_386_RELATIVE
,
845 data_shndx
, reloc
.get_r_offset());
851 // These are relocations which should only be seen by the
852 // dynamic linker, and should never be seen here.
853 case elfcpp::R_386_COPY
:
854 case elfcpp::R_386_GLOB_DAT
:
855 case elfcpp::R_386_JUMP_SLOT
:
856 case elfcpp::R_386_RELATIVE
:
857 case elfcpp::R_386_TLS_TPOFF
:
858 case elfcpp::R_386_TLS_DTPMOD32
:
859 case elfcpp::R_386_TLS_DTPOFF32
:
860 case elfcpp::R_386_TLS_TPOFF32
:
861 case elfcpp::R_386_TLS_DESC
:
862 gold_error(_("%s: unexpected reloc %u in object file"),
863 object
->name().c_str(), r_type
);
866 // These are initial TLS relocs, which are expected when
868 case elfcpp::R_386_TLS_GD
: // Global-dynamic
869 case elfcpp::R_386_TLS_GOTDESC
: // Global-dynamic (from ~oliva url)
870 case elfcpp::R_386_TLS_DESC_CALL
:
871 case elfcpp::R_386_TLS_LDM
: // Local-dynamic
872 case elfcpp::R_386_TLS_LDO_32
: // Alternate local-dynamic
873 case elfcpp::R_386_TLS_IE
: // Initial-exec
874 case elfcpp::R_386_TLS_IE_32
:
875 case elfcpp::R_386_TLS_GOTIE
:
876 case elfcpp::R_386_TLS_LE
: // Local-exec
877 case elfcpp::R_386_TLS_LE_32
:
879 bool output_is_shared
= parameters
->output_is_shared();
880 const tls::Tls_optimization optimized_type
881 = Target_i386::optimize_tls_reloc(!output_is_shared
, r_type
);
884 case elfcpp::R_386_TLS_GD
: // Global-dynamic
885 case elfcpp::R_386_TLS_GOTDESC
: // Global-dynamic (from ~oliva)
886 case elfcpp::R_386_TLS_DESC_CALL
:
887 // FIXME: If not relaxing to LE, we need to generate
888 // DTPMOD32 and DTPOFF32 relocs.
889 if (optimized_type
!= tls::TLSOPT_TO_LE
)
890 unsupported_reloc_local(object
, r_type
);
893 case elfcpp::R_386_TLS_LDM
: // Local-dynamic
894 // FIXME: If not relaxing to LE, we need to generate a
896 if (optimized_type
!= tls::TLSOPT_TO_LE
)
897 unsupported_reloc_local(object
, r_type
);
900 case elfcpp::R_386_TLS_LDO_32
: // Alternate local-dynamic
903 case elfcpp::R_386_TLS_IE
: // Initial-exec
904 case elfcpp::R_386_TLS_IE_32
:
905 case elfcpp::R_386_TLS_GOTIE
:
906 // FIXME: If not relaxing to LE, we need to generate a
907 // TPOFF or TPOFF32 reloc.
908 if (optimized_type
!= tls::TLSOPT_TO_LE
)
909 unsupported_reloc_local(object
, r_type
);
912 case elfcpp::R_386_TLS_LE
: // Local-exec
913 case elfcpp::R_386_TLS_LE_32
:
914 // FIXME: If generating a shared object, we need to copy
915 // this relocation into the object.
916 gold_assert(!output_is_shared
);
925 case elfcpp::R_386_32PLT
:
926 case elfcpp::R_386_TLS_GD_32
:
927 case elfcpp::R_386_TLS_GD_PUSH
:
928 case elfcpp::R_386_TLS_GD_CALL
:
929 case elfcpp::R_386_TLS_GD_POP
:
930 case elfcpp::R_386_TLS_LDM_32
:
931 case elfcpp::R_386_TLS_LDM_PUSH
:
932 case elfcpp::R_386_TLS_LDM_CALL
:
933 case elfcpp::R_386_TLS_LDM_POP
:
934 case elfcpp::R_386_USED_BY_INTEL_200
:
936 unsupported_reloc_local(object
, r_type
);
941 // Report an unsupported relocation against a global symbol.
944 Target_i386::Scan::unsupported_reloc_global(Sized_relobj
<32, false>* object
,
948 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
949 object
->name().c_str(), r_type
, gsym
->name());
952 // Scan a relocation for a global symbol.
955 Target_i386::Scan::global(const General_options
& options
,
956 Symbol_table
* symtab
,
959 Sized_relobj
<32, false>* object
,
960 unsigned int data_shndx
,
961 const elfcpp::Rel
<32, false>& reloc
,
967 case elfcpp::R_386_NONE
:
968 case elfcpp::R_386_GNU_VTINHERIT
:
969 case elfcpp::R_386_GNU_VTENTRY
:
972 case elfcpp::R_386_32
:
973 case elfcpp::R_386_16
:
974 case elfcpp::R_386_8
:
976 // Make a PLT entry if necessary.
977 if (gsym
->needs_plt_entry())
979 target
->make_plt_entry(symtab
, layout
, gsym
);
980 // Since this is not a PC-relative relocation, we may be
981 // taking the address of a function. In that case we need to
982 // set the entry in the dynamic symbol table to the address of
984 if (gsym
->is_from_dynobj())
985 gsym
->set_needs_dynsym_value();
987 // Make a dynamic relocation if necessary.
988 if (gsym
->needs_dynamic_reloc(true, false))
990 if (target
->may_need_copy_reloc(gsym
))
992 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
995 else if (r_type
== elfcpp::R_386_32
996 && gsym
->can_use_relative_reloc(false))
998 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
999 rel_dyn
->add_local(object
, 0, elfcpp::R_386_RELATIVE
, data_shndx
,
1000 reloc
.get_r_offset());
1004 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1005 rel_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
1006 reloc
.get_r_offset());
1012 case elfcpp::R_386_PC32
:
1013 case elfcpp::R_386_PC16
:
1014 case elfcpp::R_386_PC8
:
1016 // Make a PLT entry if necessary.
1017 if (gsym
->needs_plt_entry())
1018 target
->make_plt_entry(symtab
, layout
, gsym
);
1019 // Make a dynamic relocation if necessary.
1020 bool is_function_call
= (gsym
->type() == elfcpp::STT_FUNC
);
1021 if (gsym
->needs_dynamic_reloc(false, is_function_call
))
1023 if (target
->may_need_copy_reloc(gsym
))
1025 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
1030 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1031 rel_dyn
->add_global(gsym
, r_type
, object
, data_shndx
,
1032 reloc
.get_r_offset());
1038 case elfcpp::R_386_GOT32
:
1040 // The symbol requires a GOT entry.
1041 Output_data_got
<32, false>* got
= target
->got_section(symtab
, layout
);
1042 if (got
->add_global(gsym
))
1044 // If this symbol is not fully resolved, we need to add a
1045 // dynamic relocation for it.
1046 if (!gsym
->final_value_is_known())
1048 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1049 if (gsym
->is_from_dynobj()
1050 || gsym
->is_preemptible())
1051 rel_dyn
->add_global(gsym
, elfcpp::R_386_GLOB_DAT
, got
,
1052 gsym
->got_offset());
1055 rel_dyn
->add_local(object
, 0, elfcpp::R_386_RELATIVE
,
1056 got
, gsym
->got_offset());
1057 // Make sure we write the link-time value to the GOT.
1058 gsym
->set_needs_value_in_got();
1065 case elfcpp::R_386_PLT32
:
1066 // If the symbol is fully resolved, this is just a PC32 reloc.
1067 // Otherwise we need a PLT entry.
1068 if (gsym
->final_value_is_known())
1070 // If building a shared library, we can also skip the PLT entry
1071 // if the symbol is defined in the output file and is protected
1073 if (gsym
->is_defined()
1074 && !gsym
->is_from_dynobj()
1075 && !gsym
->is_preemptible())
1077 target
->make_plt_entry(symtab
, layout
, gsym
);
1080 case elfcpp::R_386_GOTOFF
:
1081 case elfcpp::R_386_GOTPC
:
1082 // We need a GOT section.
1083 target
->got_section(symtab
, layout
);
1086 // These are relocations which should only be seen by the
1087 // dynamic linker, and should never be seen here.
1088 case elfcpp::R_386_COPY
:
1089 case elfcpp::R_386_GLOB_DAT
:
1090 case elfcpp::R_386_JUMP_SLOT
:
1091 case elfcpp::R_386_RELATIVE
:
1092 case elfcpp::R_386_TLS_TPOFF
:
1093 case elfcpp::R_386_TLS_DTPMOD32
:
1094 case elfcpp::R_386_TLS_DTPOFF32
:
1095 case elfcpp::R_386_TLS_TPOFF32
:
1096 case elfcpp::R_386_TLS_DESC
:
1097 gold_error(_("%s: unexpected reloc %u in object file"),
1098 object
->name().c_str(), r_type
);
1101 // These are initial tls relocs, which are expected when
1103 case elfcpp::R_386_TLS_GD
: // Global-dynamic
1104 case elfcpp::R_386_TLS_GOTDESC
: // Global-dynamic (from ~oliva url)
1105 case elfcpp::R_386_TLS_DESC_CALL
:
1106 case elfcpp::R_386_TLS_LDM
: // Local-dynamic
1107 case elfcpp::R_386_TLS_LDO_32
: // Alternate local-dynamic
1108 case elfcpp::R_386_TLS_IE
: // Initial-exec
1109 case elfcpp::R_386_TLS_IE_32
:
1110 case elfcpp::R_386_TLS_GOTIE
:
1111 case elfcpp::R_386_TLS_LE
: // Local-exec
1112 case elfcpp::R_386_TLS_LE_32
:
1114 const bool is_final
= gsym
->final_value_is_known();
1115 const tls::Tls_optimization optimized_type
1116 = Target_i386::optimize_tls_reloc(is_final
, r_type
);
1119 case elfcpp::R_386_TLS_GD
: // Global-dynamic
1120 case elfcpp::R_386_TLS_GOTDESC
: // Global-dynamic (~oliva url)
1121 case elfcpp::R_386_TLS_DESC_CALL
:
1122 // FIXME: If not relaxing to LE, we need to generate
1123 // DTPMOD32 and DTPOFF32 relocs.
1124 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1125 unsupported_reloc_global(object
, r_type
, gsym
);
1128 case elfcpp::R_386_TLS_LDM
: // Local-dynamic
1129 // FIXME: If not relaxing to LE, we need to generate a
1131 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1132 unsupported_reloc_global(object
, r_type
, gsym
);
1135 case elfcpp::R_386_TLS_LDO_32
: // Alternate local-dynamic
1138 case elfcpp::R_386_TLS_IE
: // Initial-exec
1139 case elfcpp::R_386_TLS_IE_32
:
1140 case elfcpp::R_386_TLS_GOTIE
:
1141 // FIXME: If not relaxing to LE, we need to generate a
1142 // TPOFF or TPOFF32 reloc.
1143 if (optimized_type
!= tls::TLSOPT_TO_LE
)
1144 unsupported_reloc_global(object
, r_type
, gsym
);
1147 case elfcpp::R_386_TLS_LE
: // Local-exec
1148 case elfcpp::R_386_TLS_LE_32
:
1149 // FIXME: If generating a shared object, we need to copy
1150 // this relocation into the object.
1151 gold_assert(!parameters
->output_is_shared());
1160 case elfcpp::R_386_32PLT
:
1161 case elfcpp::R_386_TLS_GD_32
:
1162 case elfcpp::R_386_TLS_GD_PUSH
:
1163 case elfcpp::R_386_TLS_GD_CALL
:
1164 case elfcpp::R_386_TLS_GD_POP
:
1165 case elfcpp::R_386_TLS_LDM_32
:
1166 case elfcpp::R_386_TLS_LDM_PUSH
:
1167 case elfcpp::R_386_TLS_LDM_CALL
:
1168 case elfcpp::R_386_TLS_LDM_POP
:
1169 case elfcpp::R_386_USED_BY_INTEL_200
:
1171 unsupported_reloc_global(object
, r_type
, gsym
);
1176 // Scan relocations for a section.
1179 Target_i386::scan_relocs(const General_options
& options
,
1180 Symbol_table
* symtab
,
1182 Sized_relobj
<32, false>* object
,
1183 unsigned int data_shndx
,
1184 unsigned int sh_type
,
1185 const unsigned char* prelocs
,
1187 Output_section
* output_section
,
1188 bool needs_special_offset_handling
,
1189 size_t local_symbol_count
,
1190 const unsigned char* plocal_symbols
)
1192 if (sh_type
== elfcpp::SHT_RELA
)
1194 gold_error(_("%s: unsupported RELA reloc section"),
1195 object
->name().c_str());
1199 gold::scan_relocs
<32, false, Target_i386
, elfcpp::SHT_REL
,
1210 needs_special_offset_handling
,
1215 // Finalize the sections.
1218 Target_i386::do_finalize_sections(Layout
* layout
)
1220 // Fill in some more dynamic tags.
1221 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1224 if (this->got_plt_
!= NULL
)
1225 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1227 if (this->plt_
!= NULL
)
1229 const Output_data
* od
= this->plt_
->rel_plt();
1230 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1231 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1232 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_REL
);
1235 if (this->rel_dyn_
!= NULL
)
1237 const Output_data
* od
= this->rel_dyn_
;
1238 odyn
->add_section_address(elfcpp::DT_REL
, od
);
1239 odyn
->add_section_size(elfcpp::DT_RELSZ
, od
);
1240 odyn
->add_constant(elfcpp::DT_RELENT
,
1241 elfcpp::Elf_sizes
<32>::rel_size
);
1244 if (!parameters
->output_is_shared())
1246 // The value of the DT_DEBUG tag is filled in by the dynamic
1247 // linker at run time, and used by the debugger.
1248 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1252 // Emit any relocs we saved in an attempt to avoid generating COPY
1254 if (this->copy_relocs_
== NULL
)
1256 if (this->copy_relocs_
->any_to_emit())
1258 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
1259 this->copy_relocs_
->emit(rel_dyn
);
1261 delete this->copy_relocs_
;
1262 this->copy_relocs_
= NULL
;
1265 // Return whether a direct absolute static relocation needs to be applied.
1266 // In cases where Scan::local() or Scan::global() has created
1267 // a dynamic relocation other than R_386_RELATIVE, the addend
1268 // of the relocation is carried in the data, and we must not
1269 // apply the static relocation.
1272 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol
<32>* gsym
,
1273 bool is_absolute_ref
,
1274 bool is_function_call
,
1277 // For local symbols, we will have created a non-RELATIVE dynamic
1278 // relocation only if (a) the output is position independent,
1279 // (b) the relocation is absolute (not pc- or segment-relative), and
1280 // (c) the relocation is not 32 bits wide.
1282 return !(parameters
->output_is_position_independent()
1286 // For global symbols, we use the same helper routines used in the scan pass.
1287 return !(gsym
->needs_dynamic_reloc(is_absolute_ref
, is_function_call
)
1288 && !gsym
->can_use_relative_reloc(is_function_call
));
1291 // Perform a relocation.
1294 Target_i386::Relocate::relocate(const Relocate_info
<32, false>* relinfo
,
1295 Target_i386
* target
,
1297 const elfcpp::Rel
<32, false>& rel
,
1298 unsigned int r_type
,
1299 const Sized_symbol
<32>* gsym
,
1300 const Symbol_value
<32>* psymval
,
1301 unsigned char* view
,
1302 elfcpp::Elf_types
<32>::Elf_Addr address
,
1305 if (this->skip_call_tls_get_addr_
)
1307 if (r_type
!= elfcpp::R_386_PLT32
1309 || strcmp(gsym
->name(), "___tls_get_addr") != 0)
1310 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1311 _("missing expected TLS relocation"));
1314 this->skip_call_tls_get_addr_
= false;
1319 // Pick the value to use for symbols defined in shared objects.
1320 Symbol_value
<32> symval
;
1322 && (gsym
->is_from_dynobj()
1323 || (parameters
->output_is_shared()
1324 && gsym
->is_preemptible()))
1325 && gsym
->has_plt_offset())
1327 symval
.set_output_value(target
->plt_section()->address()
1328 + gsym
->plt_offset());
1332 const Sized_relobj
<32, false>* object
= relinfo
->object
;
1334 // Get the GOT offset if needed.
1335 // The GOT pointer points to the end of the GOT section.
1336 // We need to subtract the size of the GOT section to get
1337 // the actual offset to use in the relocation.
1338 bool have_got_offset
= false;
1339 unsigned int got_offset
= 0;
1342 case elfcpp::R_386_GOT32
:
1345 gold_assert(gsym
->has_got_offset());
1346 got_offset
= gsym
->got_offset() - target
->got_size();
1350 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(rel
.get_r_info());
1351 got_offset
= object
->local_got_offset(r_sym
) - target
->got_size();
1353 have_got_offset
= true;
1362 case elfcpp::R_386_NONE
:
1363 case elfcpp::R_386_GNU_VTINHERIT
:
1364 case elfcpp::R_386_GNU_VTENTRY
:
1367 case elfcpp::R_386_32
:
1368 if (should_apply_static_reloc(gsym
, true, false, true))
1369 Relocate_functions
<32, false>::rel32(view
, object
, psymval
);
1372 case elfcpp::R_386_PC32
:
1374 bool is_function_call
= (gsym
!= NULL
1375 && gsym
->type() == elfcpp::STT_FUNC
);
1376 if (should_apply_static_reloc(gsym
, false, is_function_call
, true))
1377 Relocate_functions
<32, false>::pcrel32(view
, object
, psymval
, address
);
1381 case elfcpp::R_386_16
:
1382 if (should_apply_static_reloc(gsym
, true, false, false))
1383 Relocate_functions
<32, false>::rel16(view
, object
, psymval
);
1386 case elfcpp::R_386_PC16
:
1388 bool is_function_call
= (gsym
!= NULL
1389 && gsym
->type() == elfcpp::STT_FUNC
);
1390 if (should_apply_static_reloc(gsym
, false, is_function_call
, false))
1391 Relocate_functions
<32, false>::pcrel32(view
, object
, psymval
, address
);
1395 case elfcpp::R_386_8
:
1396 if (should_apply_static_reloc(gsym
, true, false, false))
1397 Relocate_functions
<32, false>::rel8(view
, object
, psymval
);
1400 case elfcpp::R_386_PC8
:
1402 bool is_function_call
= (gsym
!= NULL
1403 && gsym
->type() == elfcpp::STT_FUNC
);
1404 if (should_apply_static_reloc(gsym
, false, is_function_call
, false))
1405 Relocate_functions
<32, false>::pcrel32(view
, object
, psymval
, address
);
1409 case elfcpp::R_386_PLT32
:
1410 gold_assert(gsym
== NULL
1411 || gsym
->has_plt_offset()
1412 || gsym
->final_value_is_known());
1413 Relocate_functions
<32, false>::pcrel32(view
, object
, psymval
, address
);
1416 case elfcpp::R_386_GOT32
:
1417 gold_assert(have_got_offset
);
1418 Relocate_functions
<32, false>::rel32(view
, got_offset
);
1421 case elfcpp::R_386_GOTOFF
:
1423 elfcpp::Elf_types
<32>::Elf_Addr value
;
1424 value
= (psymval
->value(object
, 0)
1425 - target
->got_plt_section()->address());
1426 Relocate_functions
<32, false>::rel32(view
, value
);
1430 case elfcpp::R_386_GOTPC
:
1432 elfcpp::Elf_types
<32>::Elf_Addr value
;
1433 value
= target
->got_plt_section()->address();
1434 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1438 case elfcpp::R_386_COPY
:
1439 case elfcpp::R_386_GLOB_DAT
:
1440 case elfcpp::R_386_JUMP_SLOT
:
1441 case elfcpp::R_386_RELATIVE
:
1442 // These are outstanding tls relocs, which are unexpected when
1444 case elfcpp::R_386_TLS_TPOFF
:
1445 case elfcpp::R_386_TLS_DTPMOD32
:
1446 case elfcpp::R_386_TLS_DTPOFF32
:
1447 case elfcpp::R_386_TLS_TPOFF32
:
1448 case elfcpp::R_386_TLS_DESC
:
1449 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1450 _("unexpected reloc %u in object file"),
1454 // These are initial tls relocs, which are expected when
1456 case elfcpp::R_386_TLS_GD
: // Global-dynamic
1457 case elfcpp::R_386_TLS_GOTDESC
: // Global-dynamic (from ~oliva url)
1458 case elfcpp::R_386_TLS_DESC_CALL
:
1459 case elfcpp::R_386_TLS_LDM
: // Local-dynamic
1460 case elfcpp::R_386_TLS_LDO_32
: // Alternate local-dynamic
1461 case elfcpp::R_386_TLS_IE
: // Initial-exec
1462 case elfcpp::R_386_TLS_IE_32
:
1463 case elfcpp::R_386_TLS_GOTIE
:
1464 case elfcpp::R_386_TLS_LE
: // Local-exec
1465 case elfcpp::R_386_TLS_LE_32
:
1466 this->relocate_tls(relinfo
, relnum
, rel
, r_type
, gsym
, psymval
, view
,
1467 address
, view_size
);
1470 case elfcpp::R_386_32PLT
:
1471 case elfcpp::R_386_TLS_GD_32
:
1472 case elfcpp::R_386_TLS_GD_PUSH
:
1473 case elfcpp::R_386_TLS_GD_CALL
:
1474 case elfcpp::R_386_TLS_GD_POP
:
1475 case elfcpp::R_386_TLS_LDM_32
:
1476 case elfcpp::R_386_TLS_LDM_PUSH
:
1477 case elfcpp::R_386_TLS_LDM_CALL
:
1478 case elfcpp::R_386_TLS_LDM_POP
:
1479 case elfcpp::R_386_USED_BY_INTEL_200
:
1481 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1482 _("unsupported reloc %u"),
1490 // Perform a TLS relocation.
1493 Target_i386::Relocate::relocate_tls(const Relocate_info
<32, false>* relinfo
,
1495 const elfcpp::Rel
<32, false>& rel
,
1496 unsigned int r_type
,
1497 const Sized_symbol
<32>* gsym
,
1498 const Symbol_value
<32>* psymval
,
1499 unsigned char* view
,
1500 elfcpp::Elf_types
<32>::Elf_Addr
,
1503 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1504 if (tls_segment
== NULL
)
1506 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1507 _("TLS reloc but no TLS segment"));
1511 elfcpp::Elf_types
<32>::Elf_Addr value
= psymval
->value(relinfo
->object
, 0);
1513 const bool is_final
= (gsym
== NULL
1514 ? !parameters
->output_is_position_independent()
1515 : gsym
->final_value_is_known());
1516 const tls::Tls_optimization optimized_type
1517 = Target_i386::optimize_tls_reloc(is_final
, r_type
);
1520 case elfcpp::R_386_TLS_GD
: // Global-dynamic
1521 if (optimized_type
== tls::TLSOPT_TO_LE
)
1523 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1524 rel
, r_type
, value
, view
,
1528 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1529 _("unsupported reloc %u"),
1533 case elfcpp::R_386_TLS_GOTDESC
: // Global-dynamic (from ~oliva url)
1534 case elfcpp::R_386_TLS_DESC_CALL
:
1535 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1536 _("unsupported reloc %u"),
1540 case elfcpp::R_386_TLS_LDM
: // Local-dynamic
1541 if (this->local_dynamic_type_
== LOCAL_DYNAMIC_SUN
)
1543 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1544 _("both SUN and GNU model "
1545 "TLS relocations"));
1548 this->local_dynamic_type_
= LOCAL_DYNAMIC_GNU
;
1549 if (optimized_type
== tls::TLSOPT_TO_LE
)
1551 this->tls_ld_to_le(relinfo
, relnum
, tls_segment
, rel
, r_type
,
1552 value
, view
, view_size
);
1555 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1556 _("unsupported reloc %u"),
1560 case elfcpp::R_386_TLS_LDO_32
: // Alternate local-dynamic
1561 // This reloc can appear in debugging sections, in which case we
1562 // won't see the TLS_LDM reloc. The local_dynamic_type field
1564 if (optimized_type
!= tls::TLSOPT_TO_LE
1565 || this->local_dynamic_type_
== LOCAL_DYNAMIC_NONE
)
1566 value
= value
- tls_segment
->vaddr();
1567 else if (this->local_dynamic_type_
== LOCAL_DYNAMIC_GNU
)
1568 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1570 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1571 Relocate_functions
<32, false>::rel32(view
, value
);
1574 case elfcpp::R_386_TLS_IE
: // Initial-exec
1575 case elfcpp::R_386_TLS_GOTIE
:
1576 case elfcpp::R_386_TLS_IE_32
:
1577 if (optimized_type
== tls::TLSOPT_TO_LE
)
1579 Target_i386::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1580 rel
, r_type
, value
, view
,
1584 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1585 _("unsupported reloc %u"),
1589 case elfcpp::R_386_TLS_LE
: // Local-exec
1590 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1591 Relocate_functions
<32, false>::rel32(view
, value
);
1594 case elfcpp::R_386_TLS_LE_32
:
1595 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1596 Relocate_functions
<32, false>::rel32(view
, value
);
1601 // Do a relocation in which we convert a TLS General-Dynamic to a
1605 Target_i386::Relocate::tls_gd_to_le(const Relocate_info
<32, false>* relinfo
,
1607 Output_segment
* tls_segment
,
1608 const elfcpp::Rel
<32, false>& rel
,
1610 elfcpp::Elf_types
<32>::Elf_Addr value
,
1611 unsigned char* view
,
1614 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1615 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1616 // leal foo(%reg),%eax; call ___tls_get_addr
1617 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1619 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1620 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 9);
1622 unsigned char op1
= view
[-1];
1623 unsigned char op2
= view
[-2];
1625 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1626 op2
== 0x8d || op2
== 0x04);
1627 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), view
[4] == 0xe8);
1633 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -3);
1634 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), view
[-3] == 0x8d);
1635 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1636 ((op1
& 0xc7) == 0x05 && op1
!= (4 << 3)));
1637 memcpy(view
- 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1641 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1642 (op1
& 0xf8) == 0x80 && (op1
& 7) != 4);
1643 if (static_cast<off_t
>(rel
.get_r_offset() + 9) < view_size
1646 // There is a trailing nop. Use the size byte subl.
1647 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1652 // Use the five byte subl.
1653 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1657 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1658 Relocate_functions
<32, false>::rel32(view
+ roff
, value
);
1660 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1662 this->skip_call_tls_get_addr_
= true;
1665 // Do a relocation in which we convert a TLS Local-Dynamic to a
1669 Target_i386::Relocate::tls_ld_to_le(const Relocate_info
<32, false>* relinfo
,
1672 const elfcpp::Rel
<32, false>& rel
,
1674 elfcpp::Elf_types
<32>::Elf_Addr
,
1675 unsigned char* view
,
1678 // leal foo(%reg), %eax; call ___tls_get_addr
1679 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1681 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1682 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 9);
1684 // FIXME: Does this test really always pass?
1685 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1686 view
[-2] == 0x8d && view
[-1] == 0x83);
1688 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), view
[4] == 0xe8);
1690 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1692 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1694 this->skip_call_tls_get_addr_
= true;
1697 // Do a relocation in which we convert a TLS Initial-Exec to a
1701 Target_i386::Relocate::tls_ie_to_le(const Relocate_info
<32, false>* relinfo
,
1703 Output_segment
* tls_segment
,
1704 const elfcpp::Rel
<32, false>& rel
,
1705 unsigned int r_type
,
1706 elfcpp::Elf_types
<32>::Elf_Addr value
,
1707 unsigned char* view
,
1710 // We have to actually change the instructions, which means that we
1711 // need to examine the opcodes to figure out which instruction we
1713 if (r_type
== elfcpp::R_386_TLS_IE
)
1715 // movl %gs:XX,%eax ==> movl $YY,%eax
1716 // movl %gs:XX,%reg ==> movl $YY,%reg
1717 // addl %gs:XX,%reg ==> addl $YY,%reg
1718 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -1);
1719 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 4);
1721 unsigned char op1
= view
[-1];
1724 // movl XX,%eax ==> movl $YY,%eax
1729 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1731 unsigned char op2
= view
[-2];
1734 // movl XX,%reg ==> movl $YY,%reg
1735 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1736 (op1
& 0xc7) == 0x05);
1738 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1740 else if (op2
== 0x03)
1742 // addl XX,%reg ==> addl $YY,%reg
1743 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1744 (op1
& 0xc7) == 0x05);
1746 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1749 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), 0);
1754 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1755 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1756 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1757 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, -2);
1758 tls::check_range(relinfo
, relnum
, rel
.get_r_offset(), view_size
, 4);
1760 unsigned char op1
= view
[-1];
1761 unsigned char op2
= view
[-2];
1762 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(),
1763 (op1
& 0xc0) == 0x80 && (op1
& 7) != 4);
1766 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1768 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1770 else if (op2
== 0x2b)
1772 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1774 view
[-1] = 0xe8 | ((op1
>> 3) & 7);
1776 else if (op2
== 0x03)
1778 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1780 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1783 tls::check_tls(relinfo
, relnum
, rel
.get_r_offset(), 0);
1786 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1787 if (r_type
== elfcpp::R_386_TLS_IE
|| r_type
== elfcpp::R_386_TLS_GOTIE
)
1790 Relocate_functions
<32, false>::rel32(view
, value
);
1793 // Relocate section data.
1796 Target_i386::relocate_section(const Relocate_info
<32, false>* relinfo
,
1797 unsigned int sh_type
,
1798 const unsigned char* prelocs
,
1800 Output_section
* output_section
,
1801 bool needs_special_offset_handling
,
1802 unsigned char* view
,
1803 elfcpp::Elf_types
<32>::Elf_Addr address
,
1806 gold_assert(sh_type
== elfcpp::SHT_REL
);
1808 gold::relocate_section
<32, false, Target_i386
, elfcpp::SHT_REL
,
1809 Target_i386::Relocate
>(
1815 needs_special_offset_handling
,
1821 // Return the value to use for a dynamic which requires special
1822 // treatment. This is how we support equality comparisons of function
1823 // pointers across shared library boundaries, as described in the
1824 // processor specific ABI supplement.
1827 Target_i386::do_dynsym_value(const Symbol
* gsym
) const
1829 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1830 return this->plt_section()->address() + gsym
->plt_offset();
1833 // Return a string used to fill a code section with nops to take up
1834 // the specified length.
1837 Target_i386::do_code_fill(off_t length
)
1841 // Build a jmp instruction to skip over the bytes.
1842 unsigned char jmp
[5];
1844 elfcpp::Swap_unaligned
<32, false>::writeval(jmp
+ 1, length
- 5);
1845 return (std::string(reinterpret_cast<char*>(&jmp
[0]), 5)
1846 + std::string(length
- 5, '\0'));
1849 // Nop sequences of various lengths.
1850 const char nop1
[1] = { 0x90 }; // nop
1851 const char nop2
[2] = { 0x66, 0x90 }; // xchg %ax %ax
1852 const char nop3
[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1853 const char nop4
[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1854 const char nop5
[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1855 0x00 }; // leal 0(%esi,1),%esi
1856 const char nop6
[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1858 const char nop7
[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1860 const char nop8
[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1861 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1862 const char nop9
[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1863 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1865 const char nop10
[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1866 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1868 const char nop11
[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1869 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1871 const char nop12
[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1872 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1873 0x00, 0x00, 0x00, 0x00 };
1874 const char nop13
[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1875 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1876 0x27, 0x00, 0x00, 0x00,
1878 const char nop14
[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1879 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1880 0xbc, 0x27, 0x00, 0x00,
1882 const char nop15
[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1883 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1884 0x90, 0x90, 0x90, 0x90,
1887 const char* nops
[16] = {
1889 nop1
, nop2
, nop3
, nop4
, nop5
, nop6
, nop7
,
1890 nop8
, nop9
, nop10
, nop11
, nop12
, nop13
, nop14
, nop15
1893 return std::string(nops
[length
], length
);
1896 // The selector for i386 object files.
1898 class Target_selector_i386
: public Target_selector
1901 Target_selector_i386()
1902 : Target_selector(elfcpp::EM_386
, 32, false)
1906 recognize(int machine
, int osabi
, int abiversion
);
1909 Target_i386
* target_
;
1912 // Recognize an i386 object file when we already know that the machine
1913 // number is EM_386.
1916 Target_selector_i386::recognize(int, int, int)
1918 if (this->target_
== NULL
)
1919 this->target_
= new Target_i386();
1920 return this->target_
;
1923 Target_selector_i386 target_selector_i386
;
1925 } // End anonymous namespace.