1 // i386.cc -- i386 target support for gold.
15 #include "target-reloc.h"
16 #include "target-select.h"
23 class Output_data_plt_i386
;
25 // The i386 target class.
27 class Target_i386
: public Sized_target
<32, false>
30 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, false> Reloc_section
;
33 : Sized_target
<32, false>(&i386_info
),
34 got_(NULL
), plt_(NULL
), got_plt_(NULL
), rel_dyn_(NULL
),
35 copy_relocs_(NULL
), dynbss_(NULL
)
38 // Scan the relocations to look for symbol adjustments.
40 scan_relocs(const General_options
& options
,
43 Sized_relobj
<32, false>* object
,
44 unsigned int data_shndx
,
46 const unsigned char* prelocs
,
48 size_t local_symbol_count
,
49 const unsigned char* plocal_symbols
,
50 Symbol
** global_symbols
);
52 // Finalize the sections.
54 do_finalize_sections(const General_options
*, Layout
*);
56 // Relocate a section.
58 relocate_section(const Relocate_info
<32, false>*,
60 const unsigned char* prelocs
,
63 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
67 // The class which scans relocations.
71 local(const General_options
& options
, Symbol_table
* symtab
,
72 Layout
* layout
, Target_i386
* target
,
73 Sized_relobj
<32, false>* object
,
74 unsigned int data_shndx
,
75 const elfcpp::Rel
<32, false>& reloc
, unsigned int r_type
,
76 const elfcpp::Sym
<32, false>& lsym
);
79 global(const General_options
& options
, Symbol_table
* symtab
,
80 Layout
* layout
, Target_i386
* target
,
81 Sized_relobj
<32, false>* object
,
82 unsigned int data_shndx
,
83 const elfcpp::Rel
<32, false>& reloc
, unsigned int r_type
,
87 // The class which implements relocation.
92 : skip_call_tls_get_addr_(false)
97 if (this->skip_call_tls_get_addr_
)
99 // FIXME: This needs to specify the location somehow.
100 fprintf(stderr
, _("%s: missing expected TLS relocation\n"),
106 // Do a relocation. Return false if the caller should not issue
107 // any warnings about this relocation.
109 relocate(const Relocate_info
<32, false>*, Target_i386
*, size_t relnum
,
110 const elfcpp::Rel
<32, false>&,
111 unsigned int r_type
, const Sized_symbol
<32>*,
112 elfcpp::Elf_types
<32>::Elf_Addr
,
113 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
,
117 // Do a TLS relocation.
119 relocate_tls(const Relocate_info
<32, false>*, size_t relnum
,
120 const elfcpp::Rel
<32, false>&,
121 unsigned int r_type
, const Sized_symbol
<32>*,
122 elfcpp::Elf_types
<32>::Elf_Addr
,
123 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
, off_t
);
125 // Do a TLS Initial-Exec to Local-Exec transition.
127 tls_ie_to_le(const Relocate_info
<32, false>*, size_t relnum
,
128 Output_segment
* tls_segment
,
129 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
130 elfcpp::Elf_types
<32>::Elf_Addr value
,
134 // Do a TLS Global-Dynamic to Local-Exec transition.
136 tls_gd_to_le(const Relocate_info
<32, false>*, size_t relnum
,
137 Output_segment
* tls_segment
,
138 const elfcpp::Rel
<32, false>&, unsigned int r_type
,
139 elfcpp::Elf_types
<32>::Elf_Addr value
,
143 // Check the range for a TLS relocation.
145 check_range(const Relocate_info
<32, false>*, size_t relnum
,
146 const elfcpp::Rel
<32, false>&, off_t
, off_t
);
148 // Check the validity of a TLS relocation. This is like assert.
150 check_tls(const Relocate_info
<32, false>*, size_t relnum
,
151 const elfcpp::Rel
<32, false>&, bool);
153 // This is set if we should skip the next reloc, which should be a
154 // PLT32 reloc against ___tls_get_addr.
155 bool skip_call_tls_get_addr_
;
158 // Adjust TLS relocation type based on the options and whether this
159 // is a local symbol.
161 optimize_tls_reloc(const General_options
*, bool is_final
, int r_type
);
163 // Get the GOT section, creating it if necessary.
164 Output_data_got
<32, false>*
165 got_section(const General_options
*, Symbol_table
*, Layout
*);
167 // Create a PLT entry for a global symbol.
169 make_plt_entry(const General_options
* options
, Symbol_table
*,
172 // Get the PLT section.
173 Output_data_plt_i386
*
176 gold_assert(this->plt_
!= NULL
);
180 // Get the dynamic reloc section, creating it if necessary.
182 rel_dyn_section(Layout
*);
184 // Copy a relocation against a global symbol.
186 copy_reloc(const General_options
*, Symbol_table
*, Layout
*,
187 Sized_relobj
<32, false>*, unsigned int,
188 Symbol
*, const elfcpp::Rel
<32, false>&);
190 // Information about this specific target which we pass to the
191 // general Target structure.
192 static const Target::Target_info i386_info
;
195 Output_data_got
<32, false>* got_
;
197 Output_data_plt_i386
* plt_
;
198 // The GOT PLT section.
199 Output_data_space
* got_plt_
;
200 // The dynamic reloc section.
201 Reloc_section
* rel_dyn_
;
202 // Relocs saved to avoid a COPY reloc.
203 Copy_relocs
<32, false>* copy_relocs_
;
204 // Space for variables copied with a COPY reloc.
205 Output_data_space
* dynbss_
;
208 const Target::Target_info
Target_i386::i386_info
=
211 false, // is_big_endian
212 elfcpp::EM_386
, // machine_code
213 false, // has_make_symbol
214 false, // has_resolve
215 "/usr/lib/libc.so.1", // dynamic_linker
216 0x08048000, // text_segment_address
217 0x1000, // abi_pagesize
218 0x1000 // common_pagesize
221 // Get the GOT section, creating it if necessary.
223 Output_data_got
<32, false>*
224 Target_i386::got_section(const General_options
* options
, Symbol_table
* symtab
,
227 if (this->got_
== NULL
)
229 gold_assert(options
!= NULL
&& symtab
!= NULL
&& layout
!= NULL
);
231 this->got_
= new Output_data_got
<32, false>(options
);
233 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
234 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
237 // The old GNU linker creates a .got.plt section. We just
238 // create another set of data in the .got section. Note that we
239 // always create a PLT if we create a GOT, although the PLT
241 this->got_plt_
= new Output_data_space(4);
242 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
243 elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE
,
246 // The first three entries are reserved.
247 this->got_plt_
->set_space_size(3 * 4);
249 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
250 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL
,
252 0, 0, elfcpp::STT_OBJECT
,
254 elfcpp::STV_HIDDEN
, 0,
261 // Get the dynamic reloc section, creating it if necessary.
263 Target_i386::Reloc_section
*
264 Target_i386::rel_dyn_section(Layout
* layout
)
266 if (this->rel_dyn_
== NULL
)
268 gold_assert(layout
!= NULL
);
269 this->rel_dyn_
= new Reloc_section();
270 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
271 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
273 return this->rel_dyn_
;
276 // A class to handle the PLT data.
278 class Output_data_plt_i386
: public Output_section_data
281 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, false> Reloc_section
;
283 Output_data_plt_i386(Layout
*, Output_data_space
*, bool is_shared
);
285 // Add an entry to the PLT.
287 add_entry(Symbol
* gsym
);
289 // Return the .rel.plt section data.
292 { return this->rel_
; }
296 do_adjust_output_section(Output_section
* os
);
299 // The size of an entry in the PLT.
300 static const int plt_entry_size
= 16;
302 // The first entry in the PLT for an executable.
303 static unsigned char exec_first_plt_entry
[plt_entry_size
];
305 // The first entry in the PLT for a shared object.
306 static unsigned char dyn_first_plt_entry
[plt_entry_size
];
308 // Other entries in the PLT for an executable.
309 static unsigned char exec_plt_entry
[plt_entry_size
];
311 // Other entries in the PLT for a shared object.
312 static unsigned char dyn_plt_entry
[plt_entry_size
];
314 // Set the final size.
316 do_set_address(uint64_t, off_t
)
317 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
319 // Write out the PLT data.
321 do_write(Output_file
*);
323 // The reloc section.
325 // The .got.plt section.
326 Output_data_space
* got_plt_
;
327 // The number of PLT entries.
329 // Whether we are generated a shared object.
333 // Create the PLT section. The ordinary .got section is an argument,
334 // since we need to refer to the start. We also create our own .got
335 // section just for PLT entries.
337 Output_data_plt_i386::Output_data_plt_i386(Layout
* layout
,
338 Output_data_space
* got_plt
,
340 : Output_section_data(4), got_plt_(got_plt
), is_shared_(is_shared
)
342 this->rel_
= new Reloc_section();
343 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
344 elfcpp::SHF_ALLOC
, this->rel_
);
350 Output_data_plt_i386::do_adjust_output_section(Output_section
* os
)
352 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
353 // linker, and so do we.
357 // Add an entry to the PLT.
360 Output_data_plt_i386::add_entry(Symbol
* gsym
)
362 gold_assert(!gsym
->has_plt_offset());
364 // Note that when setting the PLT offset we skip the initial
365 // reserved PLT entry.
366 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
370 off_t got_offset
= this->got_plt_
->data_size();
372 // Every PLT entry needs a GOT entry which points back to the PLT
373 // entry (this will be changed by the dynamic linker, normally
374 // lazily when the function is called).
375 this->got_plt_
->set_space_size(got_offset
+ 4);
377 // Every PLT entry needs a reloc.
378 gsym
->set_needs_dynsym_entry();
379 this->rel_
->add_global(gsym
, elfcpp::R_386_JUMP_SLOT
, this->got_plt_
,
382 // Note that we don't need to save the symbol. The contents of the
383 // PLT are independent of which symbols are used. The symbols only
384 // appear in the relocations.
387 // The first entry in the PLT for an executable.
389 unsigned char Output_data_plt_i386::exec_first_plt_entry
[plt_entry_size
] =
391 0xff, 0x35, // pushl contents of memory address
392 0, 0, 0, 0, // replaced with address of .got + 4
393 0xff, 0x25, // jmp indirect
394 0, 0, 0, 0, // replaced with address of .got + 8
398 // The first entry in the PLT for a shared object.
400 unsigned char Output_data_plt_i386::dyn_first_plt_entry
[plt_entry_size
] =
402 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
403 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
407 // Subsequent entries in the PLT for an executable.
409 unsigned char Output_data_plt_i386::exec_plt_entry
[plt_entry_size
] =
411 0xff, 0x25, // jmp indirect
412 0, 0, 0, 0, // replaced with address of symbol in .got
413 0x68, // pushl immediate
414 0, 0, 0, 0, // replaced with offset into relocation table
415 0xe9, // jmp relative
416 0, 0, 0, 0 // replaced with offset to start of .plt
419 // Subsequent entries in the PLT for a shared object.
421 unsigned char Output_data_plt_i386::dyn_plt_entry
[plt_entry_size
] =
423 0xff, 0xa3, // jmp *offset(%ebx)
424 0, 0, 0, 0, // replaced with offset of symbol in .got
425 0x68, // pushl immediate
426 0, 0, 0, 0, // replaced with offset into relocation table
427 0xe9, // jmp relative
428 0, 0, 0, 0 // replaced with offset to start of .plt
431 // Write out the PLT. This uses the hand-coded instructions above,
432 // and adjusts them as needed. This is all specified by the i386 ELF
433 // Processor Supplement.
436 Output_data_plt_i386::do_write(Output_file
* of
)
438 const off_t offset
= this->offset();
439 const off_t oview_size
= this->data_size();
440 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
442 const off_t got_file_offset
= this->got_plt_
->offset();
443 const off_t got_size
= this->got_plt_
->data_size();
444 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
447 unsigned char* pov
= oview
;
449 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
450 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
452 if (this->is_shared_
)
453 memcpy(pov
, dyn_first_plt_entry
, plt_entry_size
);
456 memcpy(pov
, exec_first_plt_entry
, plt_entry_size
);
457 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 4);
458 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 8);
460 pov
+= plt_entry_size
;
462 unsigned char* got_pov
= got_view
;
464 memset(got_pov
, 0, 12);
467 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
469 unsigned int plt_offset
= plt_entry_size
;
470 unsigned int plt_rel_offset
= 0;
471 unsigned int got_offset
= 12;
472 const unsigned int count
= this->count_
;
473 for (unsigned int i
= 0;
476 pov
+= plt_entry_size
,
478 plt_offset
+= plt_entry_size
,
479 plt_rel_offset
+= rel_size
,
482 // Set and adjust the PLT entry itself.
484 if (this->is_shared_
)
486 memcpy(pov
, dyn_plt_entry
, plt_entry_size
);
487 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_offset
);
491 memcpy(pov
, exec_plt_entry
, plt_entry_size
);
492 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
497 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_rel_offset
);
498 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
499 - (plt_offset
+ plt_entry_size
));
501 // Set the entry in the GOT.
502 elfcpp::Swap
<32, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
505 gold_assert(pov
- oview
== oview_size
);
506 gold_assert(got_pov
- got_view
== got_size
);
508 of
->write_output_view(offset
, oview_size
, oview
);
509 of
->write_output_view(got_file_offset
, got_size
, got_view
);
512 // Create a PLT entry for a global symbol.
515 Target_i386::make_plt_entry(const General_options
* options
,
516 Symbol_table
* symtab
, Layout
* layout
, Symbol
* gsym
)
518 if (gsym
->has_plt_offset())
521 if (this->plt_
== NULL
)
523 // Create the GOT sections first.
524 this->got_section(options
, symtab
, layout
);
526 this->plt_
= new Output_data_plt_i386(layout
, this->got_plt_
,
527 options
->is_shared());
528 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
530 | elfcpp::SHF_EXECINSTR
),
534 this->plt_
->add_entry(gsym
);
537 // Handle a relocation against a non-function symbol defined in a
538 // dynamic object. The traditional way to handle this is to generate
539 // a COPY relocation to copy the variable at runtime from the shared
540 // object into the executable's data segment. However, this is
541 // undesirable in general, as if the size of the object changes in the
542 // dynamic object, the executable will no longer work correctly. If
543 // this relocation is in a writable section, then we can create a
544 // dynamic reloc and the dynamic linker will resolve it to the correct
545 // address at runtime. However, we do not want do that if the
546 // relocation is in a read-only section, as it would prevent the
547 // readonly segment from being shared. And if we have to eventually
548 // generate a COPY reloc, then any dynamic relocations will be
549 // useless. So this means that if this is a writable section, we need
550 // to save the relocation until we see whether we have to create a
551 // COPY relocation for this symbol for any other relocation.
554 Target_i386::copy_reloc(const General_options
* options
,
555 Symbol_table
* symtab
,
557 Sized_relobj
<32, false>* object
,
558 unsigned int data_shndx
, Symbol
* gsym
,
559 const elfcpp::Rel
<32, false>& rel
)
561 Sized_symbol
<32>* ssym
;
562 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(32) (gsym
565 if (!Copy_relocs
<32, false>::need_copy_reloc(options
, object
,
568 // So far we do not need a COPY reloc. Save this relocation.
569 // If it turns out that we never need a COPY reloc for this
570 // symbol, then we will emit the relocation.
571 if (this->copy_relocs_
== NULL
)
572 this->copy_relocs_
= new Copy_relocs
<32, false>();
573 this->copy_relocs_
->save(ssym
, object
, data_shndx
, rel
);
577 // Allocate space for this symbol in the .bss section.
579 elfcpp::Elf_types
<32>::Elf_WXword symsize
= ssym
->symsize();
581 // There is no defined way to determine the required alignment
582 // of the symbol. We pick the alignment based on the size. We
583 // set an arbitrary maximum of 256.
585 for (align
= 1; align
< 512; align
<<= 1)
586 if ((symsize
& align
) != 0)
589 if (this->dynbss_
== NULL
)
591 this->dynbss_
= new Output_data_space(align
);
592 layout
->add_output_section_data(".bss",
595 | elfcpp::SHF_WRITE
),
599 Output_data_space
* dynbss
= this->dynbss_
;
601 if (align
> dynbss
->addralign())
602 dynbss
->set_space_alignment(align
);
604 off_t dynbss_size
= dynbss
->data_size();
605 dynbss_size
= align_address(dynbss_size
, align
);
606 off_t offset
= dynbss_size
;
607 dynbss
->set_space_size(dynbss_size
+ symsize
);
609 // Define the symbol in the .dynbss section.
610 symtab
->define_in_output_data(this, ssym
->name(), ssym
->version(),
611 dynbss
, offset
, symsize
, ssym
->type(),
612 ssym
->binding(), ssym
->visibility(),
613 ssym
->nonvis(), false, false);
615 // Add the COPY reloc.
616 ssym
->set_needs_dynsym_entry();
617 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
618 rel_dyn
->add_global(ssym
, elfcpp::R_386_COPY
, dynbss
, offset
);
622 // Optimize the TLS relocation type based on what we know about the
623 // symbol. IS_FINAL is true if the final address of this symbol is
624 // known at link time.
627 Target_i386::optimize_tls_reloc(const General_options
* options
,
631 // If we are generating a shared library, then we can't do anything
633 if (options
->is_shared())
638 case elfcpp::R_386_TLS_GD
:
639 case elfcpp::R_386_TLS_GOTDESC
:
640 case elfcpp::R_386_TLS_DESC_CALL
:
641 // These are Global-Dynamic which permits fully general TLS
642 // access. Since we know that we are generating an executable,
643 // we can convert this to Initial-Exec. If we also know that
644 // this is a local symbol, we can further switch to Local-Exec.
646 return elfcpp::R_386_TLS_LE_32
;
647 return elfcpp::R_386_TLS_IE_32
;
649 case elfcpp::R_386_TLS_LDM
:
650 // This is Local-Dynamic, which refers to a local symbol in the
651 // dynamic TLS block. Since we know that we generating an
652 // executable, we can switch to Local-Exec.
653 return elfcpp::R_386_TLS_LE_32
;
655 case elfcpp::R_386_TLS_LDO_32
:
656 // Another type of Local-Dynamic relocation.
657 return elfcpp::R_386_TLS_LE
;
659 case elfcpp::R_386_TLS_IE
:
660 case elfcpp::R_386_TLS_GOTIE
:
661 case elfcpp::R_386_TLS_IE_32
:
662 // These are Initial-Exec relocs which get the thread offset
663 // from the GOT. If we know that we are linking against the
664 // local symbol, we can switch to Local-Exec, which links the
665 // thread offset into the instruction.
667 return elfcpp::R_386_TLS_LE_32
;
670 case elfcpp::R_386_TLS_LE
:
671 case elfcpp::R_386_TLS_LE_32
:
672 // When we already have Local-Exec, there is nothing further we
681 // Scan a relocation for a local symbol.
684 Target_i386::Scan::local(const General_options
& options
,
685 Symbol_table
* symtab
,
688 Sized_relobj
<32, false>* object
,
690 const elfcpp::Rel
<32, false>&,
692 const elfcpp::Sym
<32, false>&)
696 case elfcpp::R_386_NONE
:
697 case elfcpp::R_386_GNU_VTINHERIT
:
698 case elfcpp::R_386_GNU_VTENTRY
:
701 case elfcpp::R_386_32
:
702 case elfcpp::R_386_16
:
703 case elfcpp::R_386_8
:
704 // FIXME: If we are generating a shared object we need to copy
705 // this relocation into the object.
706 gold_assert(!options
.is_shared());
709 case elfcpp::R_386_PC32
:
710 case elfcpp::R_386_PC16
:
711 case elfcpp::R_386_PC8
:
714 case elfcpp::R_386_GOTOFF
:
715 case elfcpp::R_386_GOTPC
:
716 // We need a GOT section.
717 target
->got_section(&options
, symtab
, layout
);
720 case elfcpp::R_386_COPY
:
721 case elfcpp::R_386_GLOB_DAT
:
722 case elfcpp::R_386_JUMP_SLOT
:
723 case elfcpp::R_386_RELATIVE
:
724 case elfcpp::R_386_TLS_TPOFF
:
725 case elfcpp::R_386_TLS_DTPMOD32
:
726 case elfcpp::R_386_TLS_DTPOFF32
:
727 case elfcpp::R_386_TLS_TPOFF32
:
728 case elfcpp::R_386_TLS_DESC
:
729 fprintf(stderr
, _("%s: %s: unexpected reloc %u in object file\n"),
730 program_name
, object
->name().c_str(), r_type
);
734 case elfcpp::R_386_TLS_IE
:
735 case elfcpp::R_386_TLS_GOTIE
:
736 case elfcpp::R_386_TLS_LE
:
737 case elfcpp::R_386_TLS_GD
:
738 case elfcpp::R_386_TLS_LDM
:
739 case elfcpp::R_386_TLS_LDO_32
:
740 case elfcpp::R_386_TLS_IE_32
:
741 case elfcpp::R_386_TLS_LE_32
:
742 case elfcpp::R_386_TLS_GOTDESC
:
743 case elfcpp::R_386_TLS_DESC_CALL
:
744 r_type
= Target_i386::optimize_tls_reloc(&options
,
745 !options
.is_shared(),
749 case elfcpp::R_386_TLS_LE
:
750 case elfcpp::R_386_TLS_LE_32
:
751 // FIXME: If generating a shared object, we need to copy
752 // this relocation into the object.
753 gold_assert(!options
.is_shared());
756 case elfcpp::R_386_TLS_IE
:
757 case elfcpp::R_386_TLS_GOTIE
:
758 case elfcpp::R_386_TLS_GD
:
759 case elfcpp::R_386_TLS_LDM
:
760 case elfcpp::R_386_TLS_LDO_32
:
761 case elfcpp::R_386_TLS_IE_32
:
762 case elfcpp::R_386_TLS_GOTDESC
:
763 case elfcpp::R_386_TLS_DESC_CALL
:
765 _("%s: %s: unsupported reloc %u against local symbol\n"),
766 program_name
, object
->name().c_str(), r_type
);
771 case elfcpp::R_386_GOT32
:
772 case elfcpp::R_386_PLT32
:
773 case elfcpp::R_386_32PLT
:
774 case elfcpp::R_386_TLS_GD_32
:
775 case elfcpp::R_386_TLS_GD_PUSH
:
776 case elfcpp::R_386_TLS_GD_CALL
:
777 case elfcpp::R_386_TLS_GD_POP
:
778 case elfcpp::R_386_TLS_LDM_32
:
779 case elfcpp::R_386_TLS_LDM_PUSH
:
780 case elfcpp::R_386_TLS_LDM_CALL
:
781 case elfcpp::R_386_TLS_LDM_POP
:
782 case elfcpp::R_386_USED_BY_INTEL_200
:
784 fprintf(stderr
, _("%s: %s: unsupported reloc %u against local symbol\n"),
785 program_name
, object
->name().c_str(), r_type
);
790 // Scan a relocation for a global symbol.
793 Target_i386::Scan::global(const General_options
& options
,
794 Symbol_table
* symtab
,
797 Sized_relobj
<32, false>* object
,
798 unsigned int data_shndx
,
799 const elfcpp::Rel
<32, false>& reloc
,
805 case elfcpp::R_386_NONE
:
806 case elfcpp::R_386_GNU_VTINHERIT
:
807 case elfcpp::R_386_GNU_VTENTRY
:
810 case elfcpp::R_386_32
:
811 case elfcpp::R_386_PC32
:
812 case elfcpp::R_386_16
:
813 case elfcpp::R_386_PC16
:
814 case elfcpp::R_386_8
:
815 case elfcpp::R_386_PC8
:
816 // FIXME: If we are generating a shared object we may need to
817 // copy this relocation into the object. If this symbol is
818 // defined in a shared object, we may need to copy this
819 // relocation in order to avoid a COPY relocation.
820 gold_assert(!options
.is_shared());
822 if (gsym
->is_from_dynobj())
824 // This symbol is defined in a dynamic object. If it is a
825 // function, we make a PLT entry. Otherwise we need to
826 // either generate a COPY reloc or copy this reloc.
827 if (gsym
->type() == elfcpp::STT_FUNC
)
828 target
->make_plt_entry(&options
, symtab
, layout
, gsym
);
830 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
836 case elfcpp::R_386_GOT32
:
837 // The symbol requires a GOT entry.
838 if (target
->got_section(&options
, symtab
, layout
)->add_global(gsym
))
840 // If this symbol is not fully resolved, we need to add a
841 // dynamic relocation for it.
842 if (!gsym
->final_value_is_known(&options
))
847 case elfcpp::R_386_PLT32
:
848 // If the symbol is fully resolved, this is just a PC32 reloc.
849 // Otherwise we need a PLT entry.
850 if (gsym
->final_value_is_known(&options
))
852 target
->make_plt_entry(&options
, symtab
, layout
, gsym
);
855 case elfcpp::R_386_GOTOFF
:
856 case elfcpp::R_386_GOTPC
:
857 // We need a GOT section.
858 target
->got_section(&options
, symtab
, layout
);
861 case elfcpp::R_386_COPY
:
862 case elfcpp::R_386_GLOB_DAT
:
863 case elfcpp::R_386_JUMP_SLOT
:
864 case elfcpp::R_386_RELATIVE
:
865 case elfcpp::R_386_TLS_TPOFF
:
866 case elfcpp::R_386_TLS_DTPMOD32
:
867 case elfcpp::R_386_TLS_DTPOFF32
:
868 case elfcpp::R_386_TLS_TPOFF32
:
869 case elfcpp::R_386_TLS_DESC
:
870 fprintf(stderr
, _("%s: %s: unexpected reloc %u in object file\n"),
871 program_name
, object
->name().c_str(), r_type
);
875 case elfcpp::R_386_TLS_IE
:
876 case elfcpp::R_386_TLS_GOTIE
:
877 case elfcpp::R_386_TLS_LE
:
878 case elfcpp::R_386_TLS_GD
:
879 case elfcpp::R_386_TLS_LDM
:
880 case elfcpp::R_386_TLS_LDO_32
:
881 case elfcpp::R_386_TLS_IE_32
:
882 case elfcpp::R_386_TLS_LE_32
:
883 case elfcpp::R_386_TLS_GOTDESC
:
884 case elfcpp::R_386_TLS_DESC_CALL
:
886 const bool is_final
= gsym
->final_value_is_known(&options
);
887 r_type
= Target_i386::optimize_tls_reloc(&options
, is_final
, r_type
);
890 case elfcpp::R_386_TLS_LE
:
891 case elfcpp::R_386_TLS_LE_32
:
892 // FIXME: If generating a shared object, we need to copy
893 // this relocation into the object.
894 gold_assert(!options
.is_shared());
897 case elfcpp::R_386_TLS_IE
:
898 case elfcpp::R_386_TLS_GOTIE
:
899 case elfcpp::R_386_TLS_GD
:
900 case elfcpp::R_386_TLS_LDM
:
901 case elfcpp::R_386_TLS_LDO_32
:
902 case elfcpp::R_386_TLS_IE_32
:
903 case elfcpp::R_386_TLS_GOTDESC
:
904 case elfcpp::R_386_TLS_DESC_CALL
:
906 _("%s: %s: unsupported reloc %u "
907 "against global symbol %s\n"),
908 program_name
, object
->name().c_str(), r_type
,
915 case elfcpp::R_386_32PLT
:
916 case elfcpp::R_386_TLS_GD_32
:
917 case elfcpp::R_386_TLS_GD_PUSH
:
918 case elfcpp::R_386_TLS_GD_CALL
:
919 case elfcpp::R_386_TLS_GD_POP
:
920 case elfcpp::R_386_TLS_LDM_32
:
921 case elfcpp::R_386_TLS_LDM_PUSH
:
922 case elfcpp::R_386_TLS_LDM_CALL
:
923 case elfcpp::R_386_TLS_LDM_POP
:
924 case elfcpp::R_386_USED_BY_INTEL_200
:
927 _("%s: %s: unsupported reloc %u against global symbol %s\n"),
928 program_name
, object
->name().c_str(), r_type
, gsym
->name());
933 // Scan relocations for a section.
936 Target_i386::scan_relocs(const General_options
& options
,
937 Symbol_table
* symtab
,
939 Sized_relobj
<32, false>* object
,
940 unsigned int data_shndx
,
941 unsigned int sh_type
,
942 const unsigned char* prelocs
,
944 size_t local_symbol_count
,
945 const unsigned char* plocal_symbols
,
946 Symbol
** global_symbols
)
948 if (sh_type
== elfcpp::SHT_RELA
)
950 fprintf(stderr
, _("%s: %s: unsupported RELA reloc section\n"),
951 program_name
, object
->name().c_str());
955 gold::scan_relocs
<32, false, Target_i386
, elfcpp::SHT_REL
,
970 // Finalize the sections.
973 Target_i386::do_finalize_sections(const General_options
* options
,
976 // Fill in some more dynamic tags.
977 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
980 if (this->got_plt_
!= NULL
)
981 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
983 if (this->plt_
!= NULL
)
985 const Output_data
* od
= this->plt_
->rel_plt();
986 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
987 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
988 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_REL
);
991 if (this->rel_dyn_
!= NULL
)
993 const Output_data
* od
= this->rel_dyn_
;
994 odyn
->add_section_address(elfcpp::DT_REL
, od
);
995 odyn
->add_section_size(elfcpp::DT_RELSZ
, od
);
996 odyn
->add_constant(elfcpp::DT_RELENT
,
997 elfcpp::Elf_sizes
<32>::rel_size
);
1000 if (!options
->is_shared())
1002 // The value of the DT_DEBUG tag is filled in by the dynamic
1003 // linker at run time, and used by the debugger.
1004 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1008 // Emit any relocs we saved in an attempt to avoid generating COPY
1010 if (this->copy_relocs_
== NULL
)
1012 if (this->copy_relocs_
->any_to_emit())
1014 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
1015 this->copy_relocs_
->emit(rel_dyn
);
1017 delete this->copy_relocs_
;
1018 this->copy_relocs_
= NULL
;
1021 // Perform a relocation.
1024 Target_i386::Relocate::relocate(const Relocate_info
<32, false>* relinfo
,
1025 Target_i386
* target
,
1027 const elfcpp::Rel
<32, false>& rel
,
1028 unsigned int r_type
,
1029 const Sized_symbol
<32>* gsym
,
1030 elfcpp::Elf_types
<32>::Elf_Addr value
,
1031 unsigned char* view
,
1032 elfcpp::Elf_types
<32>::Elf_Addr address
,
1035 if (this->skip_call_tls_get_addr_
)
1037 if (r_type
!= elfcpp::R_386_PLT32
1039 || strcmp(gsym
->name(), "___tls_get_addr") != 0)
1041 fprintf(stderr
, _("%s: %s: missing expected TLS relocation\n"),
1043 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1047 this->skip_call_tls_get_addr_
= false;
1052 // Pick the value to use for symbols defined in shared objects.
1053 if (gsym
!= NULL
&& gsym
->is_from_dynobj())
1055 if (gsym
->has_plt_offset())
1056 value
= target
->plt_section()->address() + gsym
->plt_offset();
1063 case elfcpp::R_386_NONE
:
1064 case elfcpp::R_386_GNU_VTINHERIT
:
1065 case elfcpp::R_386_GNU_VTENTRY
:
1068 case elfcpp::R_386_32
:
1069 Relocate_functions
<32, false>::rel32(view
, value
);
1072 case elfcpp::R_386_PC32
:
1073 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1076 case elfcpp::R_386_16
:
1077 Relocate_functions
<32, false>::rel16(view
, value
);
1080 case elfcpp::R_386_PC16
:
1081 Relocate_functions
<32, false>::pcrel16(view
, value
, address
);
1084 case elfcpp::R_386_8
:
1085 Relocate_functions
<32, false>::rel8(view
, value
);
1088 case elfcpp::R_386_PC8
:
1089 Relocate_functions
<32, false>::pcrel8(view
, value
, address
);
1092 case elfcpp::R_386_PLT32
:
1093 gold_assert(gsym
->has_plt_offset()
1094 || gsym
->final_value_is_known(relinfo
->options
));
1095 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1098 case elfcpp::R_386_GOT32
:
1099 // Local GOT offsets not yet supported.
1101 gold_assert(gsym
->has_got_offset());
1102 value
= gsym
->got_offset();
1103 Relocate_functions
<32, false>::rel32(view
, value
);
1106 case elfcpp::R_386_GOTOFF
:
1107 value
-= target
->got_section(NULL
, NULL
, NULL
)->address();
1108 Relocate_functions
<32, false>::rel32(view
, value
);
1111 case elfcpp::R_386_GOTPC
:
1112 value
= target
->got_section(NULL
, NULL
, NULL
)->address();
1113 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1116 case elfcpp::R_386_COPY
:
1117 case elfcpp::R_386_GLOB_DAT
:
1118 case elfcpp::R_386_JUMP_SLOT
:
1119 case elfcpp::R_386_RELATIVE
:
1120 case elfcpp::R_386_TLS_TPOFF
:
1121 case elfcpp::R_386_TLS_DTPMOD32
:
1122 case elfcpp::R_386_TLS_DTPOFF32
:
1123 case elfcpp::R_386_TLS_TPOFF32
:
1124 case elfcpp::R_386_TLS_DESC
:
1125 fprintf(stderr
, _("%s: %s: unexpected reloc %u in object file\n"),
1127 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1132 case elfcpp::R_386_TLS_IE
:
1133 case elfcpp::R_386_TLS_GOTIE
:
1134 case elfcpp::R_386_TLS_LE
:
1135 case elfcpp::R_386_TLS_GD
:
1136 case elfcpp::R_386_TLS_LDM
:
1137 case elfcpp::R_386_TLS_LDO_32
:
1138 case elfcpp::R_386_TLS_IE_32
:
1139 case elfcpp::R_386_TLS_LE_32
:
1140 case elfcpp::R_386_TLS_GOTDESC
:
1141 case elfcpp::R_386_TLS_DESC_CALL
:
1142 this->relocate_tls(relinfo
, relnum
, rel
, r_type
, gsym
, value
, view
,
1143 address
, view_size
);
1146 case elfcpp::R_386_32PLT
:
1147 case elfcpp::R_386_TLS_GD_32
:
1148 case elfcpp::R_386_TLS_GD_PUSH
:
1149 case elfcpp::R_386_TLS_GD_CALL
:
1150 case elfcpp::R_386_TLS_GD_POP
:
1151 case elfcpp::R_386_TLS_LDM_32
:
1152 case elfcpp::R_386_TLS_LDM_PUSH
:
1153 case elfcpp::R_386_TLS_LDM_CALL
:
1154 case elfcpp::R_386_TLS_LDM_POP
:
1155 case elfcpp::R_386_USED_BY_INTEL_200
:
1157 fprintf(stderr
, _("%s: %s: unsupported reloc %u\n"),
1159 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1161 // gold_exit(false);
1168 // Perform a TLS relocation.
1171 Target_i386::Relocate::relocate_tls(const Relocate_info
<32, false>* relinfo
,
1173 const elfcpp::Rel
<32, false>& rel
,
1174 unsigned int r_type
,
1175 const Sized_symbol
<32>* gsym
,
1176 elfcpp::Elf_types
<32>::Elf_Addr value
,
1177 unsigned char* view
,
1178 elfcpp::Elf_types
<32>::Elf_Addr
,
1181 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1182 if (tls_segment
== NULL
)
1184 fprintf(stderr
, _("%s: %s: TLS reloc but no TLS segment\n"),
1186 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1190 const bool is_final
= (gsym
== NULL
1191 ? !relinfo
->options
->is_shared()
1192 : gsym
->final_value_is_known(relinfo
->options
));
1193 const unsigned int opt_r_type
=
1194 Target_i386::optimize_tls_reloc(relinfo
->options
, is_final
, r_type
);
1197 case elfcpp::R_386_TLS_LE_32
:
1198 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1199 Relocate_functions
<32, false>::rel32(view
, value
);
1202 case elfcpp::R_386_TLS_LE
:
1203 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1204 Relocate_functions
<32, false>::rel32(view
, value
);
1207 case elfcpp::R_386_TLS_IE
:
1208 case elfcpp::R_386_TLS_GOTIE
:
1209 case elfcpp::R_386_TLS_IE_32
:
1210 if (opt_r_type
== elfcpp::R_386_TLS_LE_32
)
1212 Target_i386::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1213 rel
, r_type
, value
, view
,
1217 fprintf(stderr
, _("%s: %s: unsupported reloc type %u\n"),
1219 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1221 // gold_exit(false);
1224 case elfcpp::R_386_TLS_GD
:
1225 if (opt_r_type
== elfcpp::R_386_TLS_LE_32
)
1227 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1228 rel
, r_type
, value
, view
,
1232 fprintf(stderr
, _("%s: %s: unsupported reloc %u\n"),
1234 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1236 // gold_exit(false);
1239 case elfcpp::R_386_TLS_LDM
:
1240 case elfcpp::R_386_TLS_LDO_32
:
1241 case elfcpp::R_386_TLS_GOTDESC
:
1242 case elfcpp::R_386_TLS_DESC_CALL
:
1243 fprintf(stderr
, _("%s: %s: unsupported reloc %u\n"),
1245 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1247 // gold_exit(false);
1252 // Do a relocation in which we convert a TLS Initial-Exec to a
1256 Target_i386::Relocate::tls_ie_to_le(const Relocate_info
<32, false>* relinfo
,
1258 Output_segment
* tls_segment
,
1259 const elfcpp::Rel
<32, false>& rel
,
1260 unsigned int r_type
,
1261 elfcpp::Elf_types
<32>::Elf_Addr value
,
1262 unsigned char* view
,
1265 // We have to actually change the instructions, which means that we
1266 // need to examine the opcodes to figure out which instruction we
1268 if (r_type
== elfcpp::R_386_TLS_IE
)
1270 // movl %gs:XX,%eax ==> movl $YY,%eax
1271 // movl %gs:XX,%reg ==> movl $YY,%reg
1272 // addl %gs:XX,%reg ==> addl $YY,%reg
1273 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -1);
1274 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, 4);
1276 unsigned char op1
= view
[-1];
1279 // movl XX,%eax ==> movl $YY,%eax
1284 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
,
1287 unsigned char op2
= view
[-2];
1290 // movl XX,%reg ==> movl $YY,%reg
1291 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1292 (op1
& 0xc7) == 0x05);
1294 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1296 else if (op2
== 0x03)
1298 // addl XX,%reg ==> addl $YY,%reg
1299 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1300 (op1
& 0xc7) == 0x05);
1302 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1305 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
, 0);
1310 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1311 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1312 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1313 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -2);
1314 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, 4);
1316 unsigned char op1
= view
[-1];
1317 unsigned char op2
= view
[-2];
1318 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1319 (op1
& 0xc0) == 0x80 && (op1
& 7) != 4);
1322 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1324 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1326 else if (op2
== 0x2b)
1328 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1330 view
[-1] = 0xe8 | ((op1
>> 3) & 7);
1332 else if (op2
== 0x03)
1334 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1336 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1339 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
, 0);
1342 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1343 if (r_type
== elfcpp::R_386_TLS_IE
|| r_type
== elfcpp::R_386_TLS_GOTIE
)
1346 Relocate_functions
<32, false>::rel32(view
, value
);
1349 // Do a relocation in which we convert a TLS Global-Dynamic to a
1353 Target_i386::Relocate::tls_gd_to_le(const Relocate_info
<32, false>* relinfo
,
1355 Output_segment
* tls_segment
,
1356 const elfcpp::Rel
<32, false>& rel
,
1358 elfcpp::Elf_types
<32>::Elf_Addr value
,
1359 unsigned char* view
,
1362 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1363 // ==> movl %gs,0,%eax; subl $foo@tpoff,%eax
1364 // leal foo(%reg),%eax; call ___tls_get_addr
1365 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1367 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -2);
1368 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, 9);
1370 unsigned char op1
= view
[-1];
1371 unsigned char op2
= view
[-2];
1373 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1374 op2
== 0x8d || op2
== 0x04);
1375 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1382 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -3);
1383 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1385 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1386 ((op1
& 0xc7) == 0x05
1387 && op1
!= (4 << 3)));
1388 memcpy(view
- 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1392 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1393 (op1
& 0xf8) == 0x80 && (op1
& 7) != 4);
1394 if (rel
.get_r_offset() + 9 < view_size
&& view
[9] == 0x90)
1396 // There is a trailing nop. Use the size byte subl.
1397 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1402 // Use the five byte subl.
1403 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1407 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1408 Relocate_functions
<32, false>::rel32(view
+ roff
, value
);
1410 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1412 this->skip_call_tls_get_addr_
= true;
1415 // Check the range for a TLS relocation.
1418 Target_i386::Relocate::check_range(const Relocate_info
<32, false>* relinfo
,
1420 const elfcpp::Rel
<32, false>& rel
,
1421 off_t view_size
, off_t off
)
1423 off_t offset
= rel
.get_r_offset() + off
;
1424 if (offset
< 0 || offset
> view_size
)
1426 fprintf(stderr
, _("%s: %s: TLS relocation out of range\n"),
1428 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1433 // Check the validity of a TLS relocation. This is like assert.
1436 Target_i386::Relocate::check_tls(const Relocate_info
<32, false>* relinfo
,
1438 const elfcpp::Rel
<32, false>& rel
,
1444 _("%s: %s: TLS relocation against invalid instruction\n"),
1446 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1451 // Relocate section data.
1454 Target_i386::relocate_section(const Relocate_info
<32, false>* relinfo
,
1455 unsigned int sh_type
,
1456 const unsigned char* prelocs
,
1458 unsigned char* view
,
1459 elfcpp::Elf_types
<32>::Elf_Addr address
,
1462 gold_assert(sh_type
== elfcpp::SHT_REL
);
1464 gold::relocate_section
<32, false, Target_i386
, elfcpp::SHT_REL
,
1465 Target_i386::Relocate
>(
1475 // The selector for i386 object files.
1477 class Target_selector_i386
: public Target_selector
1480 Target_selector_i386()
1481 : Target_selector(elfcpp::EM_386
, 32, false)
1485 recognize(int machine
, int osabi
, int abiversion
);
1488 Target_i386
* target_
;
1491 // Recognize an i386 object file when we already know that the machine
1492 // number is EM_386.
1495 Target_selector_i386::recognize(int, int, int)
1497 if (this->target_
== NULL
)
1498 this->target_
= new Target_i386();
1499 return this->target_
;
1502 Target_selector_i386 target_selector_i386
;
1504 } // End anonymous namespace.