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(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
, this->got_
);
236 // The old GNU linker creates a .got.plt section. We just
237 // create another set of data in the .got section. Note that we
238 // always create a PLT if we create a GOT, although the PLT
240 this->got_plt_
= new Output_data_space(4);
241 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
242 elfcpp::SHF_ALLOC
, this->got_plt_
);
244 // The first three entries are reserved.
245 this->got_plt_
->set_space_size(3 * 4);
247 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
248 symtab
->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_",
250 0, 0, elfcpp::STT_OBJECT
,
252 elfcpp::STV_HIDDEN
, 0,
259 // Get the dynamic reloc section, creating it if necessary.
261 Target_i386::Reloc_section
*
262 Target_i386::rel_dyn_section(Layout
* layout
)
264 if (this->rel_dyn_
== NULL
)
266 gold_assert(layout
!= NULL
);
267 this->rel_dyn_
= new Reloc_section();
268 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
269 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
271 return this->rel_dyn_
;
274 // A class to handle the PLT data.
276 class Output_data_plt_i386
: public Output_section_data
279 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, false> Reloc_section
;
281 Output_data_plt_i386(Layout
*, Output_data_space
*, bool is_shared
);
283 // Add an entry to the PLT.
285 add_entry(Symbol
* gsym
);
288 // The size of an entry in the PLT.
289 static const int plt_entry_size
= 16;
291 // The first entry in the PLT for an executable.
292 static unsigned char exec_first_plt_entry
[plt_entry_size
];
294 // The first entry in the PLT for a shared object.
295 static unsigned char dyn_first_plt_entry
[plt_entry_size
];
297 // Other entries in the PLT for an executable.
298 static unsigned char exec_plt_entry
[plt_entry_size
];
300 // Other entries in the PLT for a shared object.
301 static unsigned char dyn_plt_entry
[plt_entry_size
];
303 // Set the final size.
305 do_set_address(uint64_t, off_t
)
306 { this->set_data_size((this->count_
+ 1) * plt_entry_size
); }
308 // Write out the PLT data.
310 do_write(Output_file
*);
312 // The reloc section.
314 // The .got.plt section.
315 Output_data_space
* got_plt_
;
316 // The number of PLT entries.
318 // Whether we are generated a shared object.
322 // Create the PLT section. The ordinary .got section is an argument,
323 // since we need to refer to the start. We also create our own .got
324 // section just for PLT entries.
326 Output_data_plt_i386::Output_data_plt_i386(Layout
* layout
,
327 Output_data_space
* got_plt
,
329 : Output_section_data(4), got_plt_(got_plt
), is_shared_(is_shared
)
331 this->rel_
= new Reloc_section();
332 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
333 elfcpp::SHF_ALLOC
, this->rel_
);
336 // Add an entry to the PLT.
339 Output_data_plt_i386::add_entry(Symbol
* gsym
)
341 gold_assert(!gsym
->has_plt_offset());
343 // Note that when setting the PLT offset we skip the initial
344 // reserved PLT entry.
345 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
349 off_t got_offset
= this->got_plt_
->data_size();
351 // Every PLT entry needs a GOT entry which points back to the PLT
352 // entry (this will be changed by the dynamic linker, normally
353 // lazily when the function is called).
354 this->got_plt_
->set_space_size(got_offset
+ 4);
356 // Every PLT entry needs a reloc.
357 this->rel_
->add_global(gsym
, elfcpp::R_386_JUMP_SLOT
, this->got_plt_
,
360 // Note that we don't need to save the symbol. The contents of the
361 // PLT are independent of which symbols are used. The symbols only
362 // appear in the relocations.
365 // The first entry in the PLT for an executable.
367 unsigned char Output_data_plt_i386::exec_first_plt_entry
[plt_entry_size
] =
369 0xff, 0x35, // pushl contents of memory address
370 0, 0, 0, 0, // replaced with address of .got + 4
371 0xff, 0x25, // jmp indirect
372 0, 0, 0, 0, // replaced with address of .got + 8
376 // The first entry in the PLT for a shared object.
378 unsigned char Output_data_plt_i386::dyn_first_plt_entry
[plt_entry_size
] =
380 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
381 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
385 // Subsequent entries in the PLT for an executable.
387 unsigned char Output_data_plt_i386::exec_plt_entry
[plt_entry_size
] =
389 0xff, 0x25, // jmp indirect
390 0, 0, 0, 0, // replaced with address of symbol in .got
391 0x68, // pushl immediate
392 0, 0, 0, 0, // replaced with offset into relocation table
393 0xe9, // jmp relative
394 0, 0, 0, 0 // replaced with offset to start of .plt
397 // Subsequent entries in the PLT for a shared object.
399 unsigned char Output_data_plt_i386::dyn_plt_entry
[plt_entry_size
] =
401 0xff, 0xa3, // jmp *offset(%ebx)
402 0, 0, 0, 0, // replaced with offset of symbol in .got
403 0x68, // pushl immediate
404 0, 0, 0, 0, // replaced with offset into relocation table
405 0xe9, // jmp relative
406 0, 0, 0, 0 // replaced with offset to start of .plt
409 // Write out the PLT. This uses the hand-coded instructions above,
410 // and adjusts them as needed. This is all specified by the i386 ELF
411 // Processor Supplement.
414 Output_data_plt_i386::do_write(Output_file
* of
)
416 const off_t offset
= this->offset();
417 const off_t oview_size
= this->data_size();
418 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
420 const off_t got_file_offset
= this->got_plt_
->offset();
421 const off_t got_size
= this->got_plt_
->data_size();
422 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
425 unsigned char* pov
= oview
;
427 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
428 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
430 if (this->is_shared_
)
431 memcpy(pov
, dyn_first_plt_entry
, plt_entry_size
);
434 memcpy(pov
, exec_first_plt_entry
, plt_entry_size
);
435 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_address
+ 4);
436 elfcpp::Swap
<32, false>::writeval(pov
+ 8, got_address
+ 8);
438 pov
+= plt_entry_size
;
440 unsigned char* got_pov
= got_view
;
442 memset(got_pov
, 0, 12);
445 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
447 unsigned int plt_offset
= plt_entry_size
;
448 unsigned int plt_rel_offset
= 0;
449 unsigned int got_offset
= 12;
450 const unsigned int count
= this->count_
;
451 for (unsigned int i
= 0;
454 pov
+= plt_entry_size
,
456 plt_offset
+= plt_entry_size
,
457 plt_rel_offset
+= rel_size
,
460 // Set and adjust the PLT entry itself.
462 if (this->is_shared_
)
464 memcpy(pov
, dyn_plt_entry
, plt_entry_size
);
465 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2, got_offset
);
469 memcpy(pov
, exec_plt_entry
, plt_entry_size
);
470 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
475 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_rel_offset
);
476 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
477 - (plt_offset
+ plt_entry_size
));
479 // Set the entry in the GOT.
480 elfcpp::Swap
<32, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
483 gold_assert(pov
- oview
== oview_size
);
484 gold_assert(got_pov
- got_view
== got_size
);
486 of
->write_output_view(offset
, oview_size
, oview
);
487 of
->write_output_view(got_file_offset
, got_size
, got_view
);
490 // Create a PLT entry for a global symbol.
493 Target_i386::make_plt_entry(const General_options
* options
,
494 Symbol_table
* symtab
, Layout
* layout
, Symbol
* gsym
)
496 if (gsym
->has_plt_offset())
499 if (this->plt_
== NULL
)
501 // Create the GOT sections first.
502 this->got_section(options
, symtab
, layout
);
504 this->plt_
= new Output_data_plt_i386(layout
, this->got_plt_
,
505 options
->is_shared());
508 this->plt_
->add_entry(gsym
);
511 // Handle a relocation against a non-function symbol defined in a
512 // dynamic object. The traditional way to handle this is to generate
513 // a COPY relocation to copy the variable at runtime from the shared
514 // object into the executable's data segment. However, this is
515 // undesirable in general, as if the size of the object changes in the
516 // dynamic object, the executable will no longer work correctly. If
517 // this relocation is in a writable section, then we can create a
518 // dynamic reloc and the dynamic linker will resolve it to the correct
519 // address at runtime. However, we do not want do that if the
520 // relocation is in a read-only section, as it would prevent the
521 // readonly segment from being shared. And if we have to eventually
522 // generate a COPY reloc, then any dynamic relocations will be
523 // useless. So this means that if this is a writable section, we need
524 // to save the relocation until we see whether we have to create a
525 // COPY relocation for this symbol for any other relocation.
528 Target_i386::copy_reloc(const General_options
* options
,
529 Symbol_table
* symtab
,
531 Sized_relobj
<32, false>* object
,
532 unsigned int data_shndx
, Symbol
* gsym
,
533 const elfcpp::Rel
<32, false>& rel
)
535 Sized_symbol
<32>* ssym
;
536 ssym
= symtab
->get_sized_symbol
SELECT_SIZE_NAME(32) (gsym
539 if (!Copy_relocs
<32, false>::need_copy_reloc(options
, object
,
542 // So far we do not need a COPY reloc. Save this relocation.
543 // If it turns out that we never need a COPY reloc for this
544 // symbol, then we will emit the relocation.
545 if (this->copy_relocs_
== NULL
)
546 this->copy_relocs_
= new Copy_relocs
<32, false>();
547 this->copy_relocs_
->save(ssym
, object
, data_shndx
, rel
);
551 // Allocate space for this symbol in the .bss section.
553 elfcpp::Elf_types
<32>::Elf_WXword symsize
= ssym
->symsize();
555 // There is no defined way to determine the required alignment
556 // of the symbol. We pick the alignment based on the size. We
557 // set an arbitrary maximum of 256.
559 for (align
= 1; align
< 512; align
<<= 1)
560 if ((symsize
& align
) != 0)
563 if (this->dynbss_
== NULL
)
565 this->dynbss_
= new Output_data_space(align
);
566 layout
->add_output_section_data(".bss",
569 | elfcpp::SHF_WRITE
),
573 Output_data_space
* dynbss
= this->dynbss_
;
575 if (align
> dynbss
->addralign())
576 dynbss
->set_space_alignment(align
);
578 off_t dynbss_size
= dynbss
->data_size();
579 dynbss_size
= align_address(dynbss_size
, align
);
580 off_t offset
= dynbss_size
;
581 dynbss
->set_space_size(dynbss_size
+ symsize
);
583 // Define the symbol in the .dynbss section.
584 symtab
->define_in_output_data(this, ssym
->name(), dynbss
, offset
,
585 symsize
, ssym
->type(), ssym
->binding(),
586 ssym
->visibility(), ssym
->nonvis(),
589 // Add the COPY reloc.
590 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
591 rel_dyn
->add_global(ssym
, elfcpp::R_386_COPY
, dynbss
, offset
);
595 // Optimize the TLS relocation type based on what we know about the
596 // symbol. IS_FINAL is true if the final address of this symbol is
597 // known at link time.
600 Target_i386::optimize_tls_reloc(const General_options
* options
,
604 // If we are generating a shared library, then we can't do anything
606 if (options
->is_shared())
611 case elfcpp::R_386_TLS_GD
:
612 case elfcpp::R_386_TLS_GOTDESC
:
613 case elfcpp::R_386_TLS_DESC_CALL
:
614 // These are Global-Dynamic which permits fully general TLS
615 // access. Since we know that we are generating an executable,
616 // we can convert this to Initial-Exec. If we also know that
617 // this is a local symbol, we can further switch to Local-Exec.
619 return elfcpp::R_386_TLS_LE_32
;
620 return elfcpp::R_386_TLS_IE_32
;
622 case elfcpp::R_386_TLS_LDM
:
623 // This is Local-Dynamic, which refers to a local symbol in the
624 // dynamic TLS block. Since we know that we generating an
625 // executable, we can switch to Local-Exec.
626 return elfcpp::R_386_TLS_LE_32
;
628 case elfcpp::R_386_TLS_LDO_32
:
629 // Another type of Local-Dynamic relocation.
630 return elfcpp::R_386_TLS_LE
;
632 case elfcpp::R_386_TLS_IE
:
633 case elfcpp::R_386_TLS_GOTIE
:
634 case elfcpp::R_386_TLS_IE_32
:
635 // These are Initial-Exec relocs which get the thread offset
636 // from the GOT. If we know that we are linking against the
637 // local symbol, we can switch to Local-Exec, which links the
638 // thread offset into the instruction.
640 return elfcpp::R_386_TLS_LE_32
;
643 case elfcpp::R_386_TLS_LE
:
644 case elfcpp::R_386_TLS_LE_32
:
645 // When we already have Local-Exec, there is nothing further we
654 // Scan a relocation for a local symbol.
657 Target_i386::Scan::local(const General_options
& options
,
658 Symbol_table
* symtab
,
661 Sized_relobj
<32, false>* object
,
663 const elfcpp::Rel
<32, false>&,
665 const elfcpp::Sym
<32, false>&)
669 case elfcpp::R_386_NONE
:
670 case elfcpp::R_386_GNU_VTINHERIT
:
671 case elfcpp::R_386_GNU_VTENTRY
:
674 case elfcpp::R_386_32
:
675 case elfcpp::R_386_16
:
676 case elfcpp::R_386_8
:
677 // FIXME: If we are generating a shared object we need to copy
678 // this relocation into the object.
679 gold_assert(!options
.is_shared());
682 case elfcpp::R_386_PC32
:
683 case elfcpp::R_386_PC16
:
684 case elfcpp::R_386_PC8
:
687 case elfcpp::R_386_GOTOFF
:
688 case elfcpp::R_386_GOTPC
:
689 // We need a GOT section.
690 target
->got_section(&options
, symtab
, layout
);
693 case elfcpp::R_386_COPY
:
694 case elfcpp::R_386_GLOB_DAT
:
695 case elfcpp::R_386_JUMP_SLOT
:
696 case elfcpp::R_386_RELATIVE
:
697 case elfcpp::R_386_TLS_TPOFF
:
698 case elfcpp::R_386_TLS_DTPMOD32
:
699 case elfcpp::R_386_TLS_DTPOFF32
:
700 case elfcpp::R_386_TLS_TPOFF32
:
701 case elfcpp::R_386_TLS_DESC
:
702 fprintf(stderr
, _("%s: %s: unexpected reloc %u in object file\n"),
703 program_name
, object
->name().c_str(), r_type
);
707 case elfcpp::R_386_TLS_IE
:
708 case elfcpp::R_386_TLS_GOTIE
:
709 case elfcpp::R_386_TLS_LE
:
710 case elfcpp::R_386_TLS_GD
:
711 case elfcpp::R_386_TLS_LDM
:
712 case elfcpp::R_386_TLS_LDO_32
:
713 case elfcpp::R_386_TLS_IE_32
:
714 case elfcpp::R_386_TLS_LE_32
:
715 case elfcpp::R_386_TLS_GOTDESC
:
716 case elfcpp::R_386_TLS_DESC_CALL
:
717 r_type
= Target_i386::optimize_tls_reloc(&options
,
718 !options
.is_shared(),
722 case elfcpp::R_386_TLS_LE
:
723 case elfcpp::R_386_TLS_LE_32
:
724 // FIXME: If generating a shared object, we need to copy
725 // this relocation into the object.
726 gold_assert(!options
.is_shared());
729 case elfcpp::R_386_TLS_IE
:
730 case elfcpp::R_386_TLS_GOTIE
:
731 case elfcpp::R_386_TLS_GD
:
732 case elfcpp::R_386_TLS_LDM
:
733 case elfcpp::R_386_TLS_LDO_32
:
734 case elfcpp::R_386_TLS_IE_32
:
735 case elfcpp::R_386_TLS_GOTDESC
:
736 case elfcpp::R_386_TLS_DESC_CALL
:
738 _("%s: %s: unsupported reloc %u against local symbol\n"),
739 program_name
, object
->name().c_str(), r_type
);
744 case elfcpp::R_386_GOT32
:
745 case elfcpp::R_386_PLT32
:
746 case elfcpp::R_386_32PLT
:
747 case elfcpp::R_386_TLS_GD_32
:
748 case elfcpp::R_386_TLS_GD_PUSH
:
749 case elfcpp::R_386_TLS_GD_CALL
:
750 case elfcpp::R_386_TLS_GD_POP
:
751 case elfcpp::R_386_TLS_LDM_32
:
752 case elfcpp::R_386_TLS_LDM_PUSH
:
753 case elfcpp::R_386_TLS_LDM_CALL
:
754 case elfcpp::R_386_TLS_LDM_POP
:
755 case elfcpp::R_386_USED_BY_INTEL_200
:
757 fprintf(stderr
, _("%s: %s: unsupported reloc %u against local symbol\n"),
758 program_name
, object
->name().c_str(), r_type
);
763 // Scan a relocation for a global symbol.
766 Target_i386::Scan::global(const General_options
& options
,
767 Symbol_table
* symtab
,
770 Sized_relobj
<32, false>* object
,
771 unsigned int data_shndx
,
772 const elfcpp::Rel
<32, false>& reloc
,
778 case elfcpp::R_386_NONE
:
779 case elfcpp::R_386_GNU_VTINHERIT
:
780 case elfcpp::R_386_GNU_VTENTRY
:
783 case elfcpp::R_386_32
:
784 case elfcpp::R_386_PC32
:
785 case elfcpp::R_386_16
:
786 case elfcpp::R_386_PC16
:
787 case elfcpp::R_386_8
:
788 case elfcpp::R_386_PC8
:
789 // FIXME: If we are generating a shared object we may need to
790 // copy this relocation into the object. If this symbol is
791 // defined in a shared object, we may need to copy this
792 // relocation in order to avoid a COPY relocation.
793 gold_assert(!options
.is_shared());
795 if (gsym
->is_defined_in_dynobj())
797 // This symbol is defined in a dynamic object. If it is a
798 // function, we make a PLT entry. Otherwise we need to
799 // either generate a COPY reloc or copy this reloc.
800 if (gsym
->type() == elfcpp::STT_FUNC
)
801 target
->make_plt_entry(&options
, symtab
, layout
, gsym
);
803 target
->copy_reloc(&options
, symtab
, layout
, object
, data_shndx
,
809 case elfcpp::R_386_GOT32
:
810 // The symbol requires a GOT entry.
811 if (target
->got_section(&options
, symtab
, layout
)->add_global(gsym
))
813 // If this symbol is not fully resolved, we need to add a
814 // dynamic relocation for it.
815 if (!gsym
->final_value_is_known(&options
))
820 case elfcpp::R_386_PLT32
:
821 // If the symbol is fully resolved, this is just a PC32 reloc.
822 // Otherwise we need a PLT entry.
823 if (gsym
->final_value_is_known(&options
))
825 target
->make_plt_entry(&options
, symtab
, layout
, gsym
);
828 case elfcpp::R_386_GOTOFF
:
829 case elfcpp::R_386_GOTPC
:
830 // We need a GOT section.
831 target
->got_section(&options
, symtab
, layout
);
834 case elfcpp::R_386_COPY
:
835 case elfcpp::R_386_GLOB_DAT
:
836 case elfcpp::R_386_JUMP_SLOT
:
837 case elfcpp::R_386_RELATIVE
:
838 case elfcpp::R_386_TLS_TPOFF
:
839 case elfcpp::R_386_TLS_DTPMOD32
:
840 case elfcpp::R_386_TLS_DTPOFF32
:
841 case elfcpp::R_386_TLS_TPOFF32
:
842 case elfcpp::R_386_TLS_DESC
:
843 fprintf(stderr
, _("%s: %s: unexpected reloc %u in object file\n"),
844 program_name
, object
->name().c_str(), r_type
);
848 case elfcpp::R_386_TLS_IE
:
849 case elfcpp::R_386_TLS_GOTIE
:
850 case elfcpp::R_386_TLS_LE
:
851 case elfcpp::R_386_TLS_GD
:
852 case elfcpp::R_386_TLS_LDM
:
853 case elfcpp::R_386_TLS_LDO_32
:
854 case elfcpp::R_386_TLS_IE_32
:
855 case elfcpp::R_386_TLS_LE_32
:
856 case elfcpp::R_386_TLS_GOTDESC
:
857 case elfcpp::R_386_TLS_DESC_CALL
:
859 const bool is_final
= gsym
->final_value_is_known(&options
);
860 r_type
= Target_i386::optimize_tls_reloc(&options
, is_final
, r_type
);
863 case elfcpp::R_386_TLS_LE
:
864 case elfcpp::R_386_TLS_LE_32
:
865 // FIXME: If generating a shared object, we need to copy
866 // this relocation into the object.
867 gold_assert(!options
.is_shared());
870 case elfcpp::R_386_TLS_IE
:
871 case elfcpp::R_386_TLS_GOTIE
:
872 case elfcpp::R_386_TLS_GD
:
873 case elfcpp::R_386_TLS_LDM
:
874 case elfcpp::R_386_TLS_LDO_32
:
875 case elfcpp::R_386_TLS_IE_32
:
876 case elfcpp::R_386_TLS_GOTDESC
:
877 case elfcpp::R_386_TLS_DESC_CALL
:
879 _("%s: %s: unsupported reloc %u "
880 "against global symbol %s\n"),
881 program_name
, object
->name().c_str(), r_type
,
888 case elfcpp::R_386_32PLT
:
889 case elfcpp::R_386_TLS_GD_32
:
890 case elfcpp::R_386_TLS_GD_PUSH
:
891 case elfcpp::R_386_TLS_GD_CALL
:
892 case elfcpp::R_386_TLS_GD_POP
:
893 case elfcpp::R_386_TLS_LDM_32
:
894 case elfcpp::R_386_TLS_LDM_PUSH
:
895 case elfcpp::R_386_TLS_LDM_CALL
:
896 case elfcpp::R_386_TLS_LDM_POP
:
897 case elfcpp::R_386_USED_BY_INTEL_200
:
900 _("%s: %s: unsupported reloc %u against global symbol %s\n"),
901 program_name
, object
->name().c_str(), r_type
, gsym
->name());
906 // Scan relocations for a section.
909 Target_i386::scan_relocs(const General_options
& options
,
910 Symbol_table
* symtab
,
912 Sized_relobj
<32, false>* object
,
913 unsigned int data_shndx
,
914 unsigned int sh_type
,
915 const unsigned char* prelocs
,
917 size_t local_symbol_count
,
918 const unsigned char* plocal_symbols
,
919 Symbol
** global_symbols
)
921 if (sh_type
== elfcpp::SHT_RELA
)
923 fprintf(stderr
, _("%s: %s: unsupported RELA reloc section\n"),
924 program_name
, object
->name().c_str());
928 gold::scan_relocs
<32, false, Target_i386
, elfcpp::SHT_REL
,
943 // Finalize the sections. This is where we emit any relocs we saved
944 // in an attempt to avoid generating extra COPY relocs.
947 Target_i386::do_finalize_sections(Layout
* layout
)
949 if (this->copy_relocs_
== NULL
)
951 if (this->copy_relocs_
->any_to_emit())
953 Reloc_section
* rel_dyn
= this->rel_dyn_section(layout
);
954 this->copy_relocs_
->emit(rel_dyn
);
956 delete this->copy_relocs_
;
957 this->copy_relocs_
= NULL
;
960 // Perform a relocation.
963 Target_i386::Relocate::relocate(const Relocate_info
<32, false>* relinfo
,
966 const elfcpp::Rel
<32, false>& rel
,
968 const Sized_symbol
<32>* gsym
,
969 elfcpp::Elf_types
<32>::Elf_Addr value
,
971 elfcpp::Elf_types
<32>::Elf_Addr address
,
974 if (this->skip_call_tls_get_addr_
)
976 if (r_type
!= elfcpp::R_386_PLT32
978 || strcmp(gsym
->name(), "___tls_get_addr") != 0)
980 fprintf(stderr
, _("%s: %s: missing expected TLS relocation\n"),
982 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
986 this->skip_call_tls_get_addr_
= false;
991 // Pick the value to use for symbols defined in shared objects.
992 if (gsym
!= NULL
&& gsym
->is_defined_in_dynobj())
994 if (gsym
->has_plt_offset())
995 address
= target
->plt_section()->address() + gsym
->plt_offset();
1002 case elfcpp::R_386_NONE
:
1003 case elfcpp::R_386_GNU_VTINHERIT
:
1004 case elfcpp::R_386_GNU_VTENTRY
:
1007 case elfcpp::R_386_32
:
1008 Relocate_functions
<32, false>::rel32(view
, value
);
1011 case elfcpp::R_386_PC32
:
1012 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1015 case elfcpp::R_386_16
:
1016 Relocate_functions
<32, false>::rel16(view
, value
);
1019 case elfcpp::R_386_PC16
:
1020 Relocate_functions
<32, false>::pcrel16(view
, value
, address
);
1023 case elfcpp::R_386_8
:
1024 Relocate_functions
<32, false>::rel8(view
, value
);
1027 case elfcpp::R_386_PC8
:
1028 Relocate_functions
<32, false>::pcrel8(view
, value
, address
);
1031 case elfcpp::R_386_PLT32
:
1032 gold_assert(gsym
->has_plt_offset()
1033 || gsym
->final_value_is_known(relinfo
->options
));
1034 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1037 case elfcpp::R_386_GOT32
:
1038 // Local GOT offsets not yet supported.
1040 gold_assert(gsym
->has_got_offset());
1041 value
= gsym
->got_offset();
1042 Relocate_functions
<32, false>::rel32(view
, value
);
1045 case elfcpp::R_386_GOTOFF
:
1046 value
-= target
->got_section(NULL
, NULL
, NULL
)->address();
1047 Relocate_functions
<32, false>::rel32(view
, value
);
1050 case elfcpp::R_386_GOTPC
:
1051 value
= target
->got_section(NULL
, NULL
, NULL
)->address();
1052 Relocate_functions
<32, false>::pcrel32(view
, value
, address
);
1055 case elfcpp::R_386_COPY
:
1056 case elfcpp::R_386_GLOB_DAT
:
1057 case elfcpp::R_386_JUMP_SLOT
:
1058 case elfcpp::R_386_RELATIVE
:
1059 case elfcpp::R_386_TLS_TPOFF
:
1060 case elfcpp::R_386_TLS_DTPMOD32
:
1061 case elfcpp::R_386_TLS_DTPOFF32
:
1062 case elfcpp::R_386_TLS_TPOFF32
:
1063 case elfcpp::R_386_TLS_DESC
:
1064 fprintf(stderr
, _("%s: %s: unexpected reloc %u in object file\n"),
1066 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1071 case elfcpp::R_386_TLS_IE
:
1072 case elfcpp::R_386_TLS_GOTIE
:
1073 case elfcpp::R_386_TLS_LE
:
1074 case elfcpp::R_386_TLS_GD
:
1075 case elfcpp::R_386_TLS_LDM
:
1076 case elfcpp::R_386_TLS_LDO_32
:
1077 case elfcpp::R_386_TLS_IE_32
:
1078 case elfcpp::R_386_TLS_LE_32
:
1079 case elfcpp::R_386_TLS_GOTDESC
:
1080 case elfcpp::R_386_TLS_DESC_CALL
:
1081 this->relocate_tls(relinfo
, relnum
, rel
, r_type
, gsym
, value
, view
,
1082 address
, view_size
);
1085 case elfcpp::R_386_32PLT
:
1086 case elfcpp::R_386_TLS_GD_32
:
1087 case elfcpp::R_386_TLS_GD_PUSH
:
1088 case elfcpp::R_386_TLS_GD_CALL
:
1089 case elfcpp::R_386_TLS_GD_POP
:
1090 case elfcpp::R_386_TLS_LDM_32
:
1091 case elfcpp::R_386_TLS_LDM_PUSH
:
1092 case elfcpp::R_386_TLS_LDM_CALL
:
1093 case elfcpp::R_386_TLS_LDM_POP
:
1094 case elfcpp::R_386_USED_BY_INTEL_200
:
1096 fprintf(stderr
, _("%s: %s: unsupported reloc %u\n"),
1098 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1100 // gold_exit(false);
1107 // Perform a TLS relocation.
1110 Target_i386::Relocate::relocate_tls(const Relocate_info
<32, false>* relinfo
,
1112 const elfcpp::Rel
<32, false>& rel
,
1113 unsigned int r_type
,
1114 const Sized_symbol
<32>* gsym
,
1115 elfcpp::Elf_types
<32>::Elf_Addr value
,
1116 unsigned char* view
,
1117 elfcpp::Elf_types
<32>::Elf_Addr
,
1120 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
1121 if (tls_segment
== NULL
)
1123 fprintf(stderr
, _("%s: %s: TLS reloc but no TLS segment\n"),
1125 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1129 const bool is_final
= (gsym
== NULL
1130 ? !relinfo
->options
->is_shared()
1131 : gsym
->final_value_is_known(relinfo
->options
));
1132 const unsigned int opt_r_type
=
1133 Target_i386::optimize_tls_reloc(relinfo
->options
, is_final
, r_type
);
1136 case elfcpp::R_386_TLS_LE_32
:
1137 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1138 Relocate_functions
<32, false>::rel32(view
, value
);
1141 case elfcpp::R_386_TLS_LE
:
1142 value
= value
- (tls_segment
->vaddr() + tls_segment
->memsz());
1143 Relocate_functions
<32, false>::rel32(view
, value
);
1146 case elfcpp::R_386_TLS_IE
:
1147 case elfcpp::R_386_TLS_GOTIE
:
1148 case elfcpp::R_386_TLS_IE_32
:
1149 if (opt_r_type
== elfcpp::R_386_TLS_LE_32
)
1151 Target_i386::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
1152 rel
, r_type
, value
, view
,
1156 fprintf(stderr
, _("%s: %s: unsupported reloc type %u\n"),
1158 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1160 // gold_exit(false);
1163 case elfcpp::R_386_TLS_GD
:
1164 if (opt_r_type
== elfcpp::R_386_TLS_LE_32
)
1166 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
1167 rel
, r_type
, value
, view
,
1171 fprintf(stderr
, _("%s: %s: unsupported reloc %u\n"),
1173 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1175 // gold_exit(false);
1178 case elfcpp::R_386_TLS_LDM
:
1179 case elfcpp::R_386_TLS_LDO_32
:
1180 case elfcpp::R_386_TLS_GOTDESC
:
1181 case elfcpp::R_386_TLS_DESC_CALL
:
1182 fprintf(stderr
, _("%s: %s: unsupported reloc %u\n"),
1184 relinfo
->location(relnum
, rel
.get_r_offset()).c_str(),
1186 // gold_exit(false);
1191 // Do a relocation in which we convert a TLS Initial-Exec to a
1195 Target_i386::Relocate::tls_ie_to_le(const Relocate_info
<32, false>* relinfo
,
1197 Output_segment
* tls_segment
,
1198 const elfcpp::Rel
<32, false>& rel
,
1199 unsigned int r_type
,
1200 elfcpp::Elf_types
<32>::Elf_Addr value
,
1201 unsigned char* view
,
1204 // We have to actually change the instructions, which means that we
1205 // need to examine the opcodes to figure out which instruction we
1207 if (r_type
== elfcpp::R_386_TLS_IE
)
1209 // movl %gs:XX,%eax ==> movl $YY,%eax
1210 // movl %gs:XX,%reg ==> movl $YY,%reg
1211 // addl %gs:XX,%reg ==> addl $YY,%reg
1212 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -1);
1213 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, 4);
1215 unsigned char op1
= view
[-1];
1218 // movl XX,%eax ==> movl $YY,%eax
1223 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
,
1226 unsigned char op2
= view
[-2];
1229 // movl XX,%reg ==> movl $YY,%reg
1230 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1231 (op1
& 0xc7) == 0x05);
1233 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1235 else if (op2
== 0x03)
1237 // addl XX,%reg ==> addl $YY,%reg
1238 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1239 (op1
& 0xc7) == 0x05);
1241 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1244 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
, 0);
1249 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1250 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1251 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1252 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -2);
1253 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, 4);
1255 unsigned char op1
= view
[-1];
1256 unsigned char op2
= view
[-2];
1257 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1258 (op1
& 0xc0) == 0x80 && (op1
& 7) != 4);
1261 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1263 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1265 else if (op2
== 0x2b)
1267 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1269 view
[-1] = 0xe8 | ((op1
>> 3) & 7);
1271 else if (op2
== 0x03)
1273 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1275 view
[-1] = 0xc0 | ((op1
>> 3) & 7);
1278 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
, 0);
1281 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1282 if (r_type
== elfcpp::R_386_TLS_IE
|| r_type
== elfcpp::R_386_TLS_GOTIE
)
1285 Relocate_functions
<32, false>::rel32(view
, value
);
1288 // Do a relocation in which we convert a TLS Global-Dynamic to a
1292 Target_i386::Relocate::tls_gd_to_le(const Relocate_info
<32, false>* relinfo
,
1294 Output_segment
* tls_segment
,
1295 const elfcpp::Rel
<32, false>& rel
,
1297 elfcpp::Elf_types
<32>::Elf_Addr value
,
1298 unsigned char* view
,
1301 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1302 // ==> movl %gs,0,%eax; subl $foo@tpoff,%eax
1303 // leal foo(%reg),%eax; call ___tls_get_addr
1304 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1306 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -2);
1307 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, 9);
1309 unsigned char op1
= view
[-1];
1310 unsigned char op2
= view
[-2];
1312 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1313 op2
== 0x8d || op2
== 0x04);
1314 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1321 Target_i386::Relocate::check_range(relinfo
, relnum
, rel
, view_size
, -3);
1322 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1324 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1325 ((op1
& 0xc7) == 0x05
1326 && op1
!= (4 << 3)));
1327 memcpy(view
- 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1331 Target_i386::Relocate::check_tls(relinfo
, relnum
, rel
,
1332 (op1
& 0xf8) == 0x80 && (op1
& 7) != 4);
1333 if (rel
.get_r_offset() + 9 < view_size
&& view
[9] == 0x90)
1335 // There is a trailing nop. Use the size byte subl.
1336 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1341 // Use the five byte subl.
1342 memcpy(view
- 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1346 value
= tls_segment
->vaddr() + tls_segment
->memsz() - value
;
1347 Relocate_functions
<32, false>::rel32(view
+ roff
, value
);
1349 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1351 this->skip_call_tls_get_addr_
= true;
1354 // Check the range for a TLS relocation.
1357 Target_i386::Relocate::check_range(const Relocate_info
<32, false>* relinfo
,
1359 const elfcpp::Rel
<32, false>& rel
,
1360 off_t view_size
, off_t off
)
1362 off_t offset
= rel
.get_r_offset() + off
;
1363 if (offset
< 0 || offset
> view_size
)
1365 fprintf(stderr
, _("%s: %s: TLS relocation out of range\n"),
1367 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1372 // Check the validity of a TLS relocation. This is like assert.
1375 Target_i386::Relocate::check_tls(const Relocate_info
<32, false>* relinfo
,
1377 const elfcpp::Rel
<32, false>& rel
,
1383 _("%s: %s: TLS relocation against invalid instruction\n"),
1385 relinfo
->location(relnum
, rel
.get_r_offset()).c_str());
1390 // Relocate section data.
1393 Target_i386::relocate_section(const Relocate_info
<32, false>* relinfo
,
1394 unsigned int sh_type
,
1395 const unsigned char* prelocs
,
1397 unsigned char* view
,
1398 elfcpp::Elf_types
<32>::Elf_Addr address
,
1401 gold_assert(sh_type
== elfcpp::SHT_REL
);
1403 gold::relocate_section
<32, false, Target_i386
, elfcpp::SHT_REL
,
1404 Target_i386::Relocate
>(
1414 // The selector for i386 object files.
1416 class Target_selector_i386
: public Target_selector
1419 Target_selector_i386()
1420 : Target_selector(elfcpp::EM_386
, 32, false)
1424 recognize(int machine
, int osabi
, int abiversion
);
1427 Target_i386
* target_
;
1430 // Recognize an i386 object file when we already know that the machine
1431 // number is EM_386.
1434 Target_selector_i386::recognize(int, int, int)
1436 if (this->target_
== NULL
)
1437 this->target_
= new Target_i386();
1438 return this->target_
;
1441 Target_selector_i386 target_selector_i386
;
1443 } // End anonymous namespace.