From Cary Coutant: Some x86_64 shared library fixes.
[binutils-gdb.git] / gold / i386.cc
1 // i386.cc -- i386 target support for gold.
2
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
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.
12
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.
17
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.
22
23 #include "gold.h"
24
25 #include <cstring>
26
27 #include "elfcpp.h"
28 #include "parameters.h"
29 #include "reloc.h"
30 #include "i386.h"
31 #include "object.h"
32 #include "symtab.h"
33 #include "layout.h"
34 #include "output.h"
35 #include "target.h"
36 #include "target-reloc.h"
37 #include "target-select.h"
38 #include "tls.h"
39
40 namespace
41 {
42
43 using namespace gold;
44
45 class Output_data_plt_i386;
46
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
51
52 class Target_i386 : public Sized_target<32, false>
53 {
54 public:
55 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
56
57 Target_i386()
58 : Sized_target<32, false>(&i386_info),
59 got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
60 copy_relocs_(NULL), dynbss_(NULL)
61 { }
62
63 // Scan the relocations to look for symbol adjustments.
64 void
65 scan_relocs(const General_options& options,
66 Symbol_table* symtab,
67 Layout* layout,
68 Sized_relobj<32, false>* object,
69 unsigned int data_shndx,
70 unsigned int sh_type,
71 const unsigned char* prelocs,
72 size_t reloc_count,
73 Output_section* output_section,
74 bool needs_special_offset_handling,
75 size_t local_symbol_count,
76 const unsigned char* plocal_symbols);
77
78 // Finalize the sections.
79 void
80 do_finalize_sections(Layout*);
81
82 // Return the value to use for a dynamic which requires special
83 // treatment.
84 uint64_t
85 do_dynsym_value(const Symbol*) const;
86
87 // Relocate a section.
88 void
89 relocate_section(const Relocate_info<32, false>*,
90 unsigned int sh_type,
91 const unsigned char* prelocs,
92 size_t reloc_count,
93 Output_section* output_section,
94 bool needs_special_offset_handling,
95 unsigned char* view,
96 elfcpp::Elf_types<32>::Elf_Addr view_address,
97 off_t view_size);
98
99 // Return a string used to fill a code section with nops.
100 std::string
101 do_code_fill(off_t length);
102
103 // Return whether SYM is defined by the ABI.
104 bool
105 do_is_defined_by_abi(Symbol* sym) const
106 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
107
108 // Return the size of the GOT section.
109 off_t
110 got_size()
111 {
112 gold_assert(this->got_ != NULL);
113 return this->got_->data_size();
114 }
115
116 private:
117 // The class which scans relocations.
118 struct Scan
119 {
120 inline void
121 local(const General_options& options, Symbol_table* symtab,
122 Layout* layout, Target_i386* target,
123 Sized_relobj<32, false>* object,
124 unsigned int data_shndx,
125 Output_section* output_section,
126 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
127 const elfcpp::Sym<32, false>& lsym);
128
129 inline void
130 global(const General_options& options, Symbol_table* symtab,
131 Layout* layout, Target_i386* target,
132 Sized_relobj<32, false>* object,
133 unsigned int data_shndx,
134 Output_section* output_section,
135 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
136 Symbol* gsym);
137
138 static void
139 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
140
141 static void
142 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
143 Symbol*);
144 };
145
146 // The class which implements relocation.
147 class Relocate
148 {
149 public:
150 Relocate()
151 : skip_call_tls_get_addr_(false),
152 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
153 { }
154
155 ~Relocate()
156 {
157 if (this->skip_call_tls_get_addr_)
158 {
159 // FIXME: This needs to specify the location somehow.
160 gold_error(_("missing expected TLS relocation"));
161 }
162 }
163
164 // Return whether the static relocation needs to be applied.
165 inline bool
166 should_apply_static_reloc(const Sized_symbol<32>* gsym,
167 bool is_absolute_ref,
168 bool is_function_call,
169 bool is_32bit);
170
171 // Do a relocation. Return false if the caller should not issue
172 // any warnings about this relocation.
173 inline bool
174 relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
175 const elfcpp::Rel<32, false>&,
176 unsigned int r_type, const Sized_symbol<32>*,
177 const Symbol_value<32>*,
178 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
179 off_t);
180
181 private:
182 // Do a TLS relocation.
183 inline void
184 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
185 size_t relnum, const elfcpp::Rel<32, false>&,
186 unsigned int r_type, const Sized_symbol<32>*,
187 const Symbol_value<32>*,
188 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
189
190 // Do a TLS General-Dynamic to Initial-Exec transition.
191 inline void
192 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
193 Output_segment* tls_segment,
194 const elfcpp::Rel<32, false>&, unsigned int r_type,
195 elfcpp::Elf_types<32>::Elf_Addr value,
196 unsigned char* view,
197 off_t view_size);
198
199 // Do a TLS General-Dynamic to Local-Exec transition.
200 inline void
201 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
202 Output_segment* tls_segment,
203 const elfcpp::Rel<32, false>&, unsigned int r_type,
204 elfcpp::Elf_types<32>::Elf_Addr value,
205 unsigned char* view,
206 off_t view_size);
207
208 // Do a TLS Local-Dynamic to Local-Exec transition.
209 inline void
210 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
211 Output_segment* tls_segment,
212 const elfcpp::Rel<32, false>&, unsigned int r_type,
213 elfcpp::Elf_types<32>::Elf_Addr value,
214 unsigned char* view,
215 off_t view_size);
216
217 // Do a TLS Initial-Exec to Local-Exec transition.
218 static inline void
219 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
220 Output_segment* tls_segment,
221 const elfcpp::Rel<32, false>&, unsigned int r_type,
222 elfcpp::Elf_types<32>::Elf_Addr value,
223 unsigned char* view,
224 off_t view_size);
225
226 // We need to keep track of which type of local dynamic relocation
227 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
228 enum Local_dynamic_type
229 {
230 LOCAL_DYNAMIC_NONE,
231 LOCAL_DYNAMIC_SUN,
232 LOCAL_DYNAMIC_GNU
233 };
234
235 // This is set if we should skip the next reloc, which should be a
236 // PLT32 reloc against ___tls_get_addr.
237 bool skip_call_tls_get_addr_;
238 // The type of local dynamic relocation we have seen in the section
239 // being relocated, if any.
240 Local_dynamic_type local_dynamic_type_;
241 };
242
243 // Adjust TLS relocation type based on the options and whether this
244 // is a local symbol.
245 static tls::Tls_optimization
246 optimize_tls_reloc(bool is_final, int r_type);
247
248 // Get the GOT section, creating it if necessary.
249 Output_data_got<32, false>*
250 got_section(Symbol_table*, Layout*);
251
252 // Get the GOT PLT section.
253 Output_data_space*
254 got_plt_section() const
255 {
256 gold_assert(this->got_plt_ != NULL);
257 return this->got_plt_;
258 }
259
260 // Create a PLT entry for a global symbol.
261 void
262 make_plt_entry(Symbol_table*, Layout*, Symbol*);
263
264 // Get the PLT section.
265 const Output_data_plt_i386*
266 plt_section() const
267 {
268 gold_assert(this->plt_ != NULL);
269 return this->plt_;
270 }
271
272 // Get the dynamic reloc section, creating it if necessary.
273 Reloc_section*
274 rel_dyn_section(Layout*);
275
276 // Return true if the symbol may need a COPY relocation.
277 // References from an executable object to non-function symbols
278 // defined in a dynamic object may need a COPY relocation.
279 bool
280 may_need_copy_reloc(Symbol* gsym)
281 {
282 return (!parameters->output_is_shared()
283 && gsym->is_from_dynobj()
284 && gsym->type() != elfcpp::STT_FUNC);
285 }
286
287 // Copy a relocation against a global symbol.
288 void
289 copy_reloc(const General_options*, Symbol_table*, Layout*,
290 Sized_relobj<32, false>*, unsigned int,
291 Output_section*, Symbol*, const elfcpp::Rel<32, false>&);
292
293 // Information about this specific target which we pass to the
294 // general Target structure.
295 static const Target::Target_info i386_info;
296
297 // The GOT section.
298 Output_data_got<32, false>* got_;
299 // The PLT section.
300 Output_data_plt_i386* plt_;
301 // The GOT PLT section.
302 Output_data_space* got_plt_;
303 // The dynamic reloc section.
304 Reloc_section* rel_dyn_;
305 // Relocs saved to avoid a COPY reloc.
306 Copy_relocs<32, false>* copy_relocs_;
307 // Space for variables copied with a COPY reloc.
308 Output_data_space* dynbss_;
309 };
310
311 const Target::Target_info Target_i386::i386_info =
312 {
313 32, // size
314 false, // is_big_endian
315 elfcpp::EM_386, // machine_code
316 false, // has_make_symbol
317 false, // has_resolve
318 true, // has_code_fill
319 true, // is_default_stack_executable
320 "/usr/lib/libc.so.1", // dynamic_linker
321 0x08048000, // default_text_segment_address
322 0x1000, // abi_pagesize
323 0x1000 // common_pagesize
324 };
325
326 // Get the GOT section, creating it if necessary.
327
328 Output_data_got<32, false>*
329 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
330 {
331 if (this->got_ == NULL)
332 {
333 gold_assert(symtab != NULL && layout != NULL);
334
335 this->got_ = new Output_data_got<32, false>();
336
337 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
338 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
339 this->got_);
340
341 // The old GNU linker creates a .got.plt section. We just
342 // create another set of data in the .got section. Note that we
343 // always create a PLT if we create a GOT, although the PLT
344 // might be empty.
345 this->got_plt_ = new Output_data_space(4);
346 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
347 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
348 this->got_plt_);
349
350 // The first three entries are reserved.
351 this->got_plt_->set_current_data_size(3 * 4);
352
353 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
354 symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
355 this->got_plt_,
356 0, 0, elfcpp::STT_OBJECT,
357 elfcpp::STB_LOCAL,
358 elfcpp::STV_HIDDEN, 0,
359 false, false);
360 }
361
362 return this->got_;
363 }
364
365 // Get the dynamic reloc section, creating it if necessary.
366
367 Target_i386::Reloc_section*
368 Target_i386::rel_dyn_section(Layout* layout)
369 {
370 if (this->rel_dyn_ == NULL)
371 {
372 gold_assert(layout != NULL);
373 this->rel_dyn_ = new Reloc_section();
374 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
375 elfcpp::SHF_ALLOC, this->rel_dyn_);
376 }
377 return this->rel_dyn_;
378 }
379
380 // A class to handle the PLT data.
381
382 class Output_data_plt_i386 : public Output_section_data
383 {
384 public:
385 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
386
387 Output_data_plt_i386(Layout*, Output_data_space*);
388
389 // Add an entry to the PLT.
390 void
391 add_entry(Symbol* gsym);
392
393 // Return the .rel.plt section data.
394 const Reloc_section*
395 rel_plt() const
396 { return this->rel_; }
397
398 protected:
399 void
400 do_adjust_output_section(Output_section* os);
401
402 private:
403 // The size of an entry in the PLT.
404 static const int plt_entry_size = 16;
405
406 // The first entry in the PLT for an executable.
407 static unsigned char exec_first_plt_entry[plt_entry_size];
408
409 // The first entry in the PLT for a shared object.
410 static unsigned char dyn_first_plt_entry[plt_entry_size];
411
412 // Other entries in the PLT for an executable.
413 static unsigned char exec_plt_entry[plt_entry_size];
414
415 // Other entries in the PLT for a shared object.
416 static unsigned char dyn_plt_entry[plt_entry_size];
417
418 // Set the final size.
419 void
420 set_final_data_size()
421 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
422
423 // Write out the PLT data.
424 void
425 do_write(Output_file*);
426
427 // The reloc section.
428 Reloc_section* rel_;
429 // The .got.plt section.
430 Output_data_space* got_plt_;
431 // The number of PLT entries.
432 unsigned int count_;
433 };
434
435 // Create the PLT section. The ordinary .got section is an argument,
436 // since we need to refer to the start. We also create our own .got
437 // section just for PLT entries.
438
439 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
440 Output_data_space* got_plt)
441 : Output_section_data(4), got_plt_(got_plt), count_(0)
442 {
443 this->rel_ = new Reloc_section();
444 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
445 elfcpp::SHF_ALLOC, this->rel_);
446 }
447
448 void
449 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
450 {
451 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
452 // linker, and so do we.
453 os->set_entsize(4);
454 }
455
456 // Add an entry to the PLT.
457
458 void
459 Output_data_plt_i386::add_entry(Symbol* gsym)
460 {
461 gold_assert(!gsym->has_plt_offset());
462
463 // Note that when setting the PLT offset we skip the initial
464 // reserved PLT entry.
465 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
466
467 ++this->count_;
468
469 off_t got_offset = this->got_plt_->current_data_size();
470
471 // Every PLT entry needs a GOT entry which points back to the PLT
472 // entry (this will be changed by the dynamic linker, normally
473 // lazily when the function is called).
474 this->got_plt_->set_current_data_size(got_offset + 4);
475
476 // Every PLT entry needs a reloc.
477 gsym->set_needs_dynsym_entry();
478 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
479 got_offset);
480
481 // Note that we don't need to save the symbol. The contents of the
482 // PLT are independent of which symbols are used. The symbols only
483 // appear in the relocations.
484 }
485
486 // The first entry in the PLT for an executable.
487
488 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
489 {
490 0xff, 0x35, // pushl contents of memory address
491 0, 0, 0, 0, // replaced with address of .got + 4
492 0xff, 0x25, // jmp indirect
493 0, 0, 0, 0, // replaced with address of .got + 8
494 0, 0, 0, 0 // unused
495 };
496
497 // The first entry in the PLT for a shared object.
498
499 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
500 {
501 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
502 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
503 0, 0, 0, 0 // unused
504 };
505
506 // Subsequent entries in the PLT for an executable.
507
508 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
509 {
510 0xff, 0x25, // jmp indirect
511 0, 0, 0, 0, // replaced with address of symbol in .got
512 0x68, // pushl immediate
513 0, 0, 0, 0, // replaced with offset into relocation table
514 0xe9, // jmp relative
515 0, 0, 0, 0 // replaced with offset to start of .plt
516 };
517
518 // Subsequent entries in the PLT for a shared object.
519
520 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
521 {
522 0xff, 0xa3, // jmp *offset(%ebx)
523 0, 0, 0, 0, // replaced with offset of symbol in .got
524 0x68, // pushl immediate
525 0, 0, 0, 0, // replaced with offset into relocation table
526 0xe9, // jmp relative
527 0, 0, 0, 0 // replaced with offset to start of .plt
528 };
529
530 // Write out the PLT. This uses the hand-coded instructions above,
531 // and adjusts them as needed. This is all specified by the i386 ELF
532 // Processor Supplement.
533
534 void
535 Output_data_plt_i386::do_write(Output_file* of)
536 {
537 const off_t offset = this->offset();
538 const off_t oview_size = this->data_size();
539 unsigned char* const oview = of->get_output_view(offset, oview_size);
540
541 const off_t got_file_offset = this->got_plt_->offset();
542 const off_t got_size = this->got_plt_->data_size();
543 unsigned char* const got_view = of->get_output_view(got_file_offset,
544 got_size);
545
546 unsigned char* pov = oview;
547
548 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
549 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
550
551 if (parameters->output_is_shared())
552 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
553 else
554 {
555 memcpy(pov, exec_first_plt_entry, plt_entry_size);
556 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
557 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
558 }
559 pov += plt_entry_size;
560
561 unsigned char* got_pov = got_view;
562
563 memset(got_pov, 0, 12);
564 got_pov += 12;
565
566 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
567
568 unsigned int plt_offset = plt_entry_size;
569 unsigned int plt_rel_offset = 0;
570 unsigned int got_offset = 12;
571 const unsigned int count = this->count_;
572 for (unsigned int i = 0;
573 i < count;
574 ++i,
575 pov += plt_entry_size,
576 got_pov += 4,
577 plt_offset += plt_entry_size,
578 plt_rel_offset += rel_size,
579 got_offset += 4)
580 {
581 // Set and adjust the PLT entry itself.
582
583 if (parameters->output_is_shared())
584 {
585 memcpy(pov, dyn_plt_entry, plt_entry_size);
586 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
587 }
588 else
589 {
590 memcpy(pov, exec_plt_entry, plt_entry_size);
591 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
592 (got_address
593 + got_offset));
594 }
595
596 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
597 elfcpp::Swap<32, false>::writeval(pov + 12,
598 - (plt_offset + plt_entry_size));
599
600 // Set the entry in the GOT.
601 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
602 }
603
604 gold_assert(pov - oview == oview_size);
605 gold_assert(got_pov - got_view == got_size);
606
607 of->write_output_view(offset, oview_size, oview);
608 of->write_output_view(got_file_offset, got_size, got_view);
609 }
610
611 // Create a PLT entry for a global symbol.
612
613 void
614 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
615 {
616 if (gsym->has_plt_offset())
617 return;
618
619 if (this->plt_ == NULL)
620 {
621 // Create the GOT sections first.
622 this->got_section(symtab, layout);
623
624 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
625 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
626 (elfcpp::SHF_ALLOC
627 | elfcpp::SHF_EXECINSTR),
628 this->plt_);
629 }
630
631 this->plt_->add_entry(gsym);
632 }
633
634 // Handle a relocation against a non-function symbol defined in a
635 // dynamic object. The traditional way to handle this is to generate
636 // a COPY relocation to copy the variable at runtime from the shared
637 // object into the executable's data segment. However, this is
638 // undesirable in general, as if the size of the object changes in the
639 // dynamic object, the executable will no longer work correctly. If
640 // this relocation is in a writable section, then we can create a
641 // dynamic reloc and the dynamic linker will resolve it to the correct
642 // address at runtime. However, we do not want do that if the
643 // relocation is in a read-only section, as it would prevent the
644 // readonly segment from being shared. And if we have to eventually
645 // generate a COPY reloc, then any dynamic relocations will be
646 // useless. So this means that if this is a writable section, we need
647 // to save the relocation until we see whether we have to create a
648 // COPY relocation for this symbol for any other relocation.
649
650 void
651 Target_i386::copy_reloc(const General_options* options,
652 Symbol_table* symtab,
653 Layout* layout,
654 Sized_relobj<32, false>* object,
655 unsigned int data_shndx,
656 Output_section* output_section,
657 Symbol* gsym,
658 const elfcpp::Rel<32, false>& rel)
659 {
660 Sized_symbol<32>* ssym;
661 ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
662 SELECT_SIZE(32));
663
664 if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
665 data_shndx, ssym))
666 {
667 // So far we do not need a COPY reloc. Save this relocation.
668 // If it turns out that we never need a COPY reloc for this
669 // symbol, then we will emit the relocation.
670 if (this->copy_relocs_ == NULL)
671 this->copy_relocs_ = new Copy_relocs<32, false>();
672 this->copy_relocs_->save(ssym, object, data_shndx, output_section, rel);
673 }
674 else
675 {
676 // Allocate space for this symbol in the .bss section.
677
678 elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
679
680 // There is no defined way to determine the required alignment
681 // of the symbol. We pick the alignment based on the size. We
682 // set an arbitrary maximum of 256.
683 unsigned int align;
684 for (align = 1; align < 512; align <<= 1)
685 if ((symsize & align) != 0)
686 break;
687
688 if (this->dynbss_ == NULL)
689 {
690 this->dynbss_ = new Output_data_space(align);
691 layout->add_output_section_data(".bss",
692 elfcpp::SHT_NOBITS,
693 (elfcpp::SHF_ALLOC
694 | elfcpp::SHF_WRITE),
695 this->dynbss_);
696 }
697
698 Output_data_space* dynbss = this->dynbss_;
699
700 if (align > dynbss->addralign())
701 dynbss->set_space_alignment(align);
702
703 off_t dynbss_size = dynbss->current_data_size();
704 dynbss_size = align_address(dynbss_size, align);
705 off_t offset = dynbss_size;
706 dynbss->set_current_data_size(dynbss_size + symsize);
707
708 symtab->define_with_copy_reloc(this, ssym, dynbss, offset);
709
710 // Add the COPY reloc.
711 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
712 rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
713 }
714 }
715
716 // Optimize the TLS relocation type based on what we know about the
717 // symbol. IS_FINAL is true if the final address of this symbol is
718 // known at link time.
719
720 tls::Tls_optimization
721 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
722 {
723 // If we are generating a shared library, then we can't do anything
724 // in the linker.
725 if (parameters->output_is_shared())
726 return tls::TLSOPT_NONE;
727
728 switch (r_type)
729 {
730 case elfcpp::R_386_TLS_GD:
731 case elfcpp::R_386_TLS_GOTDESC:
732 case elfcpp::R_386_TLS_DESC_CALL:
733 // These are General-Dynamic which permits fully general TLS
734 // access. Since we know that we are generating an executable,
735 // we can convert this to Initial-Exec. If we also know that
736 // this is a local symbol, we can further switch to Local-Exec.
737 if (is_final)
738 return tls::TLSOPT_TO_LE;
739 return tls::TLSOPT_TO_IE;
740
741 case elfcpp::R_386_TLS_LDM:
742 // This is Local-Dynamic, which refers to a local symbol in the
743 // dynamic TLS block. Since we know that we generating an
744 // executable, we can switch to Local-Exec.
745 return tls::TLSOPT_TO_LE;
746
747 case elfcpp::R_386_TLS_LDO_32:
748 // Another type of Local-Dynamic relocation.
749 return tls::TLSOPT_TO_LE;
750
751 case elfcpp::R_386_TLS_IE:
752 case elfcpp::R_386_TLS_GOTIE:
753 case elfcpp::R_386_TLS_IE_32:
754 // These are Initial-Exec relocs which get the thread offset
755 // from the GOT. If we know that we are linking against the
756 // local symbol, we can switch to Local-Exec, which links the
757 // thread offset into the instruction.
758 if (is_final)
759 return tls::TLSOPT_TO_LE;
760 return tls::TLSOPT_NONE;
761
762 case elfcpp::R_386_TLS_LE:
763 case elfcpp::R_386_TLS_LE_32:
764 // When we already have Local-Exec, there is nothing further we
765 // can do.
766 return tls::TLSOPT_NONE;
767
768 default:
769 gold_unreachable();
770 }
771 }
772
773 // Report an unsupported relocation against a local symbol.
774
775 void
776 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
777 unsigned int r_type)
778 {
779 gold_error(_("%s: unsupported reloc %u against local symbol"),
780 object->name().c_str(), r_type);
781 }
782
783 // Scan a relocation for a local symbol.
784
785 inline void
786 Target_i386::Scan::local(const General_options&,
787 Symbol_table* symtab,
788 Layout* layout,
789 Target_i386* target,
790 Sized_relobj<32, false>* object,
791 unsigned int data_shndx,
792 Output_section* output_section,
793 const elfcpp::Rel<32, false>& reloc,
794 unsigned int r_type,
795 const elfcpp::Sym<32, false>& lsym)
796 {
797 switch (r_type)
798 {
799 case elfcpp::R_386_NONE:
800 case elfcpp::R_386_GNU_VTINHERIT:
801 case elfcpp::R_386_GNU_VTENTRY:
802 break;
803
804 case elfcpp::R_386_32:
805 // If building a shared library (or a position-independent
806 // executable), we need to create a dynamic relocation for
807 // this location. The relocation applied at link time will
808 // apply the link-time value, so we flag the location with
809 // an R_386_RELATIVE relocation so the dynamic loader can
810 // relocate it easily.
811 if (parameters->output_is_position_independent())
812 {
813 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
814 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, output_section,
815 data_shndx, reloc.get_r_offset());
816 }
817 break;
818
819 case elfcpp::R_386_16:
820 case elfcpp::R_386_8:
821 // If building a shared library (or a position-independent
822 // executable), we need to create a dynamic relocation for
823 // this location. Because the addend needs to remain in the
824 // data section, we need to be careful not to apply this
825 // relocation statically.
826 if (parameters->output_is_position_independent())
827 {
828 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
829 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
830 rel_dyn->add_local(object, r_sym, r_type, output_section, data_shndx,
831 reloc.get_r_offset());
832 }
833 break;
834
835 case elfcpp::R_386_PC32:
836 case elfcpp::R_386_PC16:
837 case elfcpp::R_386_PC8:
838 break;
839
840 case elfcpp::R_386_PLT32:
841 // Since we know this is a local symbol, we can handle this as a
842 // PC32 reloc.
843 break;
844
845 case elfcpp::R_386_GOTOFF:
846 case elfcpp::R_386_GOTPC:
847 // We need a GOT section.
848 target->got_section(symtab, layout);
849 break;
850
851 case elfcpp::R_386_GOT32:
852 {
853 // The symbol requires a GOT entry.
854 Output_data_got<32, false>* got = target->got_section(symtab, layout);
855 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
856 if (got->add_local(object, r_sym))
857 {
858 // If we are generating a shared object, we need to add a
859 // dynamic RELATIVE relocation for this symbol's GOT entry.
860 if (parameters->output_is_position_independent())
861 {
862 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
863 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
864 got, object->local_got_offset(r_sym));
865 }
866 }
867 }
868 break;
869
870 // These are relocations which should only be seen by the
871 // dynamic linker, and should never be seen here.
872 case elfcpp::R_386_COPY:
873 case elfcpp::R_386_GLOB_DAT:
874 case elfcpp::R_386_JUMP_SLOT:
875 case elfcpp::R_386_RELATIVE:
876 case elfcpp::R_386_TLS_TPOFF:
877 case elfcpp::R_386_TLS_DTPMOD32:
878 case elfcpp::R_386_TLS_DTPOFF32:
879 case elfcpp::R_386_TLS_TPOFF32:
880 case elfcpp::R_386_TLS_DESC:
881 gold_error(_("%s: unexpected reloc %u in object file"),
882 object->name().c_str(), r_type);
883 break;
884
885 // These are initial TLS relocs, which are expected when
886 // linking.
887 case elfcpp::R_386_TLS_GD: // Global-dynamic
888 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
889 case elfcpp::R_386_TLS_DESC_CALL:
890 case elfcpp::R_386_TLS_LDM: // Local-dynamic
891 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
892 case elfcpp::R_386_TLS_IE: // Initial-exec
893 case elfcpp::R_386_TLS_IE_32:
894 case elfcpp::R_386_TLS_GOTIE:
895 case elfcpp::R_386_TLS_LE: // Local-exec
896 case elfcpp::R_386_TLS_LE_32:
897 {
898 bool output_is_shared = parameters->output_is_shared();
899 const tls::Tls_optimization optimized_type
900 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
901 switch (r_type)
902 {
903 case elfcpp::R_386_TLS_GD: // Global-dynamic
904 if (optimized_type == tls::TLSOPT_NONE)
905 {
906 // Create a pair of GOT entries for the module index and
907 // dtv-relative offset.
908 Output_data_got<32, false>* got
909 = target->got_section(symtab, layout);
910 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
911 got->add_local_tls_with_rel(object, r_sym,
912 lsym.get_st_shndx(), true,
913 target->rel_dyn_section(layout),
914 elfcpp::R_386_TLS_DTPMOD32);
915 }
916 else if (optimized_type != tls::TLSOPT_TO_LE)
917 unsupported_reloc_local(object, r_type);
918 break;
919
920 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
921 case elfcpp::R_386_TLS_DESC_CALL:
922 // FIXME: If not relaxing to LE, we need to generate
923 // a GOT entry with an R_386_TLS_DESC reloc.
924 if (optimized_type != tls::TLSOPT_TO_LE)
925 unsupported_reloc_local(object, r_type);
926 break;
927
928 case elfcpp::R_386_TLS_LDM: // Local-dynamic
929 if (optimized_type == tls::TLSOPT_NONE)
930 {
931 // Create a GOT entry for the module index.
932 Output_data_got<32, false>* got
933 = target->got_section(symtab, layout);
934 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
935 got->add_local_tls_with_rel(object, r_sym,
936 lsym.get_st_shndx(), false,
937 target->rel_dyn_section(layout),
938 elfcpp::R_386_TLS_DTPMOD32);
939 }
940 else if (optimized_type != tls::TLSOPT_TO_LE)
941 unsupported_reloc_local(object, r_type);
942 break;
943
944 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
945 break;
946
947 case elfcpp::R_386_TLS_IE: // Initial-exec
948 case elfcpp::R_386_TLS_IE_32:
949 case elfcpp::R_386_TLS_GOTIE:
950 if (optimized_type == tls::TLSOPT_NONE)
951 {
952 // For the R_386_TLS_IE relocation, we need to create a
953 // dynamic relocation when building a shared library.
954 if (r_type == elfcpp::R_386_TLS_IE
955 && parameters->output_is_shared())
956 {
957 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
958 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
959 output_section, data_shndx,
960 reloc.get_r_offset());
961 }
962 // Create a GOT entry for the tp-relative offset.
963 Output_data_got<32, false>* got
964 = target->got_section(symtab, layout);
965 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
966 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
967 ? elfcpp::R_386_TLS_TPOFF32
968 : elfcpp::R_386_TLS_TPOFF);
969 got->add_local_with_rel(object, r_sym,
970 target->rel_dyn_section(layout),
971 dyn_r_type);
972 }
973 else if (optimized_type != tls::TLSOPT_TO_LE)
974 unsupported_reloc_local(object, r_type);
975 break;
976
977 case elfcpp::R_386_TLS_LE: // Local-exec
978 case elfcpp::R_386_TLS_LE_32:
979 if (output_is_shared)
980 {
981 // We need to create a dynamic relocation.
982 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
983 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
984 ? elfcpp::R_386_TLS_TPOFF32
985 : elfcpp::R_386_TLS_TPOFF);
986 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
987 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
988 data_shndx, reloc.get_r_offset());
989 }
990 break;
991
992 default:
993 gold_unreachable();
994 }
995 }
996 break;
997
998 case elfcpp::R_386_32PLT:
999 case elfcpp::R_386_TLS_GD_32:
1000 case elfcpp::R_386_TLS_GD_PUSH:
1001 case elfcpp::R_386_TLS_GD_CALL:
1002 case elfcpp::R_386_TLS_GD_POP:
1003 case elfcpp::R_386_TLS_LDM_32:
1004 case elfcpp::R_386_TLS_LDM_PUSH:
1005 case elfcpp::R_386_TLS_LDM_CALL:
1006 case elfcpp::R_386_TLS_LDM_POP:
1007 case elfcpp::R_386_USED_BY_INTEL_200:
1008 default:
1009 unsupported_reloc_local(object, r_type);
1010 break;
1011 }
1012 }
1013
1014 // Report an unsupported relocation against a global symbol.
1015
1016 void
1017 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1018 unsigned int r_type,
1019 Symbol* gsym)
1020 {
1021 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1022 object->name().c_str(), r_type, gsym->demangled_name().c_str());
1023 }
1024
1025 // Scan a relocation for a global symbol.
1026
1027 inline void
1028 Target_i386::Scan::global(const General_options& options,
1029 Symbol_table* symtab,
1030 Layout* layout,
1031 Target_i386* target,
1032 Sized_relobj<32, false>* object,
1033 unsigned int data_shndx,
1034 Output_section* output_section,
1035 const elfcpp::Rel<32, false>& reloc,
1036 unsigned int r_type,
1037 Symbol* gsym)
1038 {
1039 switch (r_type)
1040 {
1041 case elfcpp::R_386_NONE:
1042 case elfcpp::R_386_GNU_VTINHERIT:
1043 case elfcpp::R_386_GNU_VTENTRY:
1044 break;
1045
1046 case elfcpp::R_386_32:
1047 case elfcpp::R_386_16:
1048 case elfcpp::R_386_8:
1049 {
1050 // Make a PLT entry if necessary.
1051 if (gsym->needs_plt_entry())
1052 {
1053 target->make_plt_entry(symtab, layout, gsym);
1054 // Since this is not a PC-relative relocation, we may be
1055 // taking the address of a function. In that case we need to
1056 // set the entry in the dynamic symbol table to the address of
1057 // the PLT entry.
1058 if (gsym->is_from_dynobj())
1059 gsym->set_needs_dynsym_value();
1060 }
1061 // Make a dynamic relocation if necessary.
1062 if (gsym->needs_dynamic_reloc(true, false))
1063 {
1064 if (target->may_need_copy_reloc(gsym))
1065 {
1066 target->copy_reloc(&options, symtab, layout, object,
1067 data_shndx, output_section, gsym, reloc);
1068 }
1069 else if (r_type == elfcpp::R_386_32
1070 && gsym->can_use_relative_reloc(false))
1071 {
1072 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1073 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
1074 output_section, data_shndx,
1075 reloc.get_r_offset());
1076 }
1077 else
1078 {
1079 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1080 rel_dyn->add_global(gsym, r_type, output_section, object,
1081 data_shndx, reloc.get_r_offset());
1082 }
1083 }
1084 }
1085 break;
1086
1087 case elfcpp::R_386_PC32:
1088 case elfcpp::R_386_PC16:
1089 case elfcpp::R_386_PC8:
1090 {
1091 // Make a PLT entry if necessary.
1092 if (gsym->needs_plt_entry())
1093 {
1094 // These relocations are used for function calls only in
1095 // non-PIC code. For a 32-bit relocation in a shared library,
1096 // we'll need a text relocation anyway, so we can skip the
1097 // PLT entry and let the dynamic linker bind the call directly
1098 // to the target. For smaller relocations, we should use a
1099 // PLT entry to ensure that the call can reach.
1100 if (!parameters->output_is_shared()
1101 || r_type != elfcpp::R_386_PC32)
1102 target->make_plt_entry(symtab, layout, gsym);
1103 }
1104 // Make a dynamic relocation if necessary.
1105 bool is_function_call = (gsym->type() == elfcpp::STT_FUNC);
1106 if (gsym->needs_dynamic_reloc(false, is_function_call))
1107 {
1108 if (target->may_need_copy_reloc(gsym))
1109 {
1110 target->copy_reloc(&options, symtab, layout, object,
1111 data_shndx, output_section, gsym, reloc);
1112 }
1113 else
1114 {
1115 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1116 rel_dyn->add_global(gsym, r_type, output_section, object,
1117 data_shndx, reloc.get_r_offset());
1118 }
1119 }
1120 }
1121 break;
1122
1123 case elfcpp::R_386_GOT32:
1124 {
1125 // The symbol requires a GOT entry.
1126 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1127 if (gsym->final_value_is_known())
1128 got->add_global(gsym);
1129 else
1130 {
1131 // If this symbol is not fully resolved, we need to add a
1132 // GOT entry with a dynamic relocation.
1133 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1134 if (gsym->is_from_dynobj() || gsym->is_preemptible())
1135 got->add_global_with_rel(gsym, rel_dyn, elfcpp::R_386_GLOB_DAT);
1136 else
1137 {
1138 if (got->add_global(gsym))
1139 {
1140 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
1141 got, gsym->got_offset());
1142 // Make sure we write the link-time value to the GOT.
1143 gsym->set_needs_value_in_got();
1144 }
1145 }
1146 }
1147 }
1148 break;
1149
1150 case elfcpp::R_386_PLT32:
1151 // If the symbol is fully resolved, this is just a PC32 reloc.
1152 // Otherwise we need a PLT entry.
1153 if (gsym->final_value_is_known())
1154 break;
1155 // If building a shared library, we can also skip the PLT entry
1156 // if the symbol is defined in the output file and is protected
1157 // or hidden.
1158 if (gsym->is_defined()
1159 && !gsym->is_from_dynobj()
1160 && !gsym->is_preemptible())
1161 break;
1162 target->make_plt_entry(symtab, layout, gsym);
1163 break;
1164
1165 case elfcpp::R_386_GOTOFF:
1166 case elfcpp::R_386_GOTPC:
1167 // We need a GOT section.
1168 target->got_section(symtab, layout);
1169 break;
1170
1171 // These are relocations which should only be seen by the
1172 // dynamic linker, and should never be seen here.
1173 case elfcpp::R_386_COPY:
1174 case elfcpp::R_386_GLOB_DAT:
1175 case elfcpp::R_386_JUMP_SLOT:
1176 case elfcpp::R_386_RELATIVE:
1177 case elfcpp::R_386_TLS_TPOFF:
1178 case elfcpp::R_386_TLS_DTPMOD32:
1179 case elfcpp::R_386_TLS_DTPOFF32:
1180 case elfcpp::R_386_TLS_TPOFF32:
1181 case elfcpp::R_386_TLS_DESC:
1182 gold_error(_("%s: unexpected reloc %u in object file"),
1183 object->name().c_str(), r_type);
1184 break;
1185
1186 // These are initial tls relocs, which are expected when
1187 // linking.
1188 case elfcpp::R_386_TLS_GD: // Global-dynamic
1189 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1190 case elfcpp::R_386_TLS_DESC_CALL:
1191 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1192 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1193 case elfcpp::R_386_TLS_IE: // Initial-exec
1194 case elfcpp::R_386_TLS_IE_32:
1195 case elfcpp::R_386_TLS_GOTIE:
1196 case elfcpp::R_386_TLS_LE: // Local-exec
1197 case elfcpp::R_386_TLS_LE_32:
1198 {
1199 const bool is_final = gsym->final_value_is_known();
1200 const tls::Tls_optimization optimized_type
1201 = Target_i386::optimize_tls_reloc(is_final, r_type);
1202 switch (r_type)
1203 {
1204 case elfcpp::R_386_TLS_GD: // Global-dynamic
1205 if (optimized_type == tls::TLSOPT_NONE)
1206 {
1207 // Create a pair of GOT entries for the module index and
1208 // dtv-relative offset.
1209 Output_data_got<32, false>* got
1210 = target->got_section(symtab, layout);
1211 got->add_global_tls_with_rel(gsym,
1212 target->rel_dyn_section(layout),
1213 elfcpp::R_386_TLS_DTPMOD32,
1214 elfcpp::R_386_TLS_DTPOFF32);
1215 }
1216 else if (optimized_type == tls::TLSOPT_TO_IE)
1217 {
1218 // Create a GOT entry for the tp-relative offset.
1219 Output_data_got<32, false>* got
1220 = target->got_section(symtab, layout);
1221 got->add_global_with_rel(gsym, target->rel_dyn_section(layout),
1222 elfcpp::R_386_TLS_TPOFF32);
1223 }
1224 else if (optimized_type != tls::TLSOPT_TO_LE)
1225 unsupported_reloc_global(object, r_type, gsym);
1226 break;
1227
1228 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1229 case elfcpp::R_386_TLS_DESC_CALL:
1230 // FIXME: If not relaxing to LE, we need to generate
1231 // a GOT entry with an R_386_TLS_DESC reloc.
1232 if (optimized_type != tls::TLSOPT_TO_LE)
1233 unsupported_reloc_global(object, r_type, gsym);
1234 unsupported_reloc_global(object, r_type, gsym);
1235 break;
1236
1237 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1238 // FIXME: If not relaxing to LE, we need to generate a
1239 // DTPMOD32 reloc.
1240 if (optimized_type == tls::TLSOPT_NONE)
1241 {
1242 // Create a GOT entry for the module index.
1243 Output_data_got<32, false>* got
1244 = target->got_section(symtab, layout);
1245 got->add_global_tls_with_rel(gsym,
1246 target->rel_dyn_section(layout),
1247 elfcpp::R_386_TLS_DTPMOD32);
1248 }
1249 else if (optimized_type != tls::TLSOPT_TO_LE)
1250 unsupported_reloc_global(object, r_type, gsym);
1251 break;
1252
1253 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1254 break;
1255
1256 case elfcpp::R_386_TLS_IE: // Initial-exec
1257 case elfcpp::R_386_TLS_IE_32:
1258 case elfcpp::R_386_TLS_GOTIE:
1259 if (optimized_type == tls::TLSOPT_NONE)
1260 {
1261 // For the R_386_TLS_IE relocation, we need to create a
1262 // dynamic relocation when building a shared library.
1263 if (r_type == elfcpp::R_386_TLS_IE
1264 && parameters->output_is_shared())
1265 {
1266 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1267 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
1268 output_section, data_shndx,
1269 reloc.get_r_offset());
1270 }
1271 // Create a GOT entry for the tp-relative offset.
1272 Output_data_got<32, false>* got
1273 = target->got_section(symtab, layout);
1274 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1275 ? elfcpp::R_386_TLS_TPOFF32
1276 : elfcpp::R_386_TLS_TPOFF);
1277 got->add_global_with_rel(gsym,
1278 target->rel_dyn_section(layout),
1279 dyn_r_type);
1280 }
1281 else if (optimized_type != tls::TLSOPT_TO_LE)
1282 unsupported_reloc_global(object, r_type, gsym);
1283 break;
1284
1285 case elfcpp::R_386_TLS_LE: // Local-exec
1286 case elfcpp::R_386_TLS_LE_32:
1287 if (parameters->output_is_shared())
1288 {
1289 // We need to create a dynamic relocation.
1290 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1291 ? elfcpp::R_386_TLS_TPOFF32
1292 : elfcpp::R_386_TLS_TPOFF);
1293 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1294 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1295 data_shndx, reloc.get_r_offset());
1296 }
1297 break;
1298
1299 default:
1300 gold_unreachable();
1301 }
1302 }
1303 break;
1304
1305 case elfcpp::R_386_32PLT:
1306 case elfcpp::R_386_TLS_GD_32:
1307 case elfcpp::R_386_TLS_GD_PUSH:
1308 case elfcpp::R_386_TLS_GD_CALL:
1309 case elfcpp::R_386_TLS_GD_POP:
1310 case elfcpp::R_386_TLS_LDM_32:
1311 case elfcpp::R_386_TLS_LDM_PUSH:
1312 case elfcpp::R_386_TLS_LDM_CALL:
1313 case elfcpp::R_386_TLS_LDM_POP:
1314 case elfcpp::R_386_USED_BY_INTEL_200:
1315 default:
1316 unsupported_reloc_global(object, r_type, gsym);
1317 break;
1318 }
1319 }
1320
1321 // Scan relocations for a section.
1322
1323 void
1324 Target_i386::scan_relocs(const General_options& options,
1325 Symbol_table* symtab,
1326 Layout* layout,
1327 Sized_relobj<32, false>* object,
1328 unsigned int data_shndx,
1329 unsigned int sh_type,
1330 const unsigned char* prelocs,
1331 size_t reloc_count,
1332 Output_section* output_section,
1333 bool needs_special_offset_handling,
1334 size_t local_symbol_count,
1335 const unsigned char* plocal_symbols)
1336 {
1337 if (sh_type == elfcpp::SHT_RELA)
1338 {
1339 gold_error(_("%s: unsupported RELA reloc section"),
1340 object->name().c_str());
1341 return;
1342 }
1343
1344 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1345 Target_i386::Scan>(
1346 options,
1347 symtab,
1348 layout,
1349 this,
1350 object,
1351 data_shndx,
1352 prelocs,
1353 reloc_count,
1354 output_section,
1355 needs_special_offset_handling,
1356 local_symbol_count,
1357 plocal_symbols);
1358 }
1359
1360 // Finalize the sections.
1361
1362 void
1363 Target_i386::do_finalize_sections(Layout* layout)
1364 {
1365 // Fill in some more dynamic tags.
1366 Output_data_dynamic* const odyn = layout->dynamic_data();
1367 if (odyn != NULL)
1368 {
1369 if (this->got_plt_ != NULL)
1370 odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1371
1372 if (this->plt_ != NULL)
1373 {
1374 const Output_data* od = this->plt_->rel_plt();
1375 odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1376 odyn->add_section_address(elfcpp::DT_JMPREL, od);
1377 odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1378 }
1379
1380 if (this->rel_dyn_ != NULL)
1381 {
1382 const Output_data* od = this->rel_dyn_;
1383 odyn->add_section_address(elfcpp::DT_REL, od);
1384 odyn->add_section_size(elfcpp::DT_RELSZ, od);
1385 odyn->add_constant(elfcpp::DT_RELENT,
1386 elfcpp::Elf_sizes<32>::rel_size);
1387 }
1388
1389 if (!parameters->output_is_shared())
1390 {
1391 // The value of the DT_DEBUG tag is filled in by the dynamic
1392 // linker at run time, and used by the debugger.
1393 odyn->add_constant(elfcpp::DT_DEBUG, 0);
1394 }
1395 }
1396
1397 // Emit any relocs we saved in an attempt to avoid generating COPY
1398 // relocs.
1399 if (this->copy_relocs_ == NULL)
1400 return;
1401 if (this->copy_relocs_->any_to_emit())
1402 {
1403 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1404 this->copy_relocs_->emit(rel_dyn);
1405 }
1406 delete this->copy_relocs_;
1407 this->copy_relocs_ = NULL;
1408 }
1409
1410 // Return whether a direct absolute static relocation needs to be applied.
1411 // In cases where Scan::local() or Scan::global() has created
1412 // a dynamic relocation other than R_386_RELATIVE, the addend
1413 // of the relocation is carried in the data, and we must not
1414 // apply the static relocation.
1415
1416 inline bool
1417 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1418 bool is_absolute_ref,
1419 bool is_function_call,
1420 bool is_32bit)
1421 {
1422 // For local symbols, we will have created a non-RELATIVE dynamic
1423 // relocation only if (a) the output is position independent,
1424 // (b) the relocation is absolute (not pc- or segment-relative), and
1425 // (c) the relocation is not 32 bits wide.
1426 if (gsym == NULL)
1427 return !(parameters->output_is_position_independent()
1428 && is_absolute_ref
1429 && !is_32bit);
1430
1431 // For global symbols, we use the same helper routines used in the scan pass.
1432 return !(gsym->needs_dynamic_reloc(is_absolute_ref, is_function_call)
1433 && !gsym->can_use_relative_reloc(is_function_call));
1434 }
1435
1436 // Perform a relocation.
1437
1438 inline bool
1439 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1440 Target_i386* target,
1441 size_t relnum,
1442 const elfcpp::Rel<32, false>& rel,
1443 unsigned int r_type,
1444 const Sized_symbol<32>* gsym,
1445 const Symbol_value<32>* psymval,
1446 unsigned char* view,
1447 elfcpp::Elf_types<32>::Elf_Addr address,
1448 off_t view_size)
1449 {
1450 if (this->skip_call_tls_get_addr_)
1451 {
1452 if (r_type != elfcpp::R_386_PLT32
1453 || gsym == NULL
1454 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1455 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1456 _("missing expected TLS relocation"));
1457 else
1458 {
1459 this->skip_call_tls_get_addr_ = false;
1460 return false;
1461 }
1462 }
1463
1464 // Pick the value to use for symbols defined in shared objects.
1465 Symbol_value<32> symval;
1466 if (gsym != NULL
1467 && (gsym->is_from_dynobj()
1468 || (parameters->output_is_shared()
1469 && gsym->is_preemptible()))
1470 && gsym->has_plt_offset())
1471 {
1472 symval.set_output_value(target->plt_section()->address()
1473 + gsym->plt_offset());
1474 psymval = &symval;
1475 }
1476
1477 const Sized_relobj<32, false>* object = relinfo->object;
1478
1479 // Get the GOT offset if needed.
1480 // The GOT pointer points to the end of the GOT section.
1481 // We need to subtract the size of the GOT section to get
1482 // the actual offset to use in the relocation.
1483 bool have_got_offset = false;
1484 unsigned int got_offset = 0;
1485 switch (r_type)
1486 {
1487 case elfcpp::R_386_GOT32:
1488 if (gsym != NULL)
1489 {
1490 gold_assert(gsym->has_got_offset());
1491 got_offset = gsym->got_offset() - target->got_size();
1492 }
1493 else
1494 {
1495 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1496 gold_assert(object->local_has_got_offset(r_sym));
1497 got_offset = object->local_got_offset(r_sym) - target->got_size();
1498 }
1499 have_got_offset = true;
1500 break;
1501
1502 default:
1503 break;
1504 }
1505
1506 switch (r_type)
1507 {
1508 case elfcpp::R_386_NONE:
1509 case elfcpp::R_386_GNU_VTINHERIT:
1510 case elfcpp::R_386_GNU_VTENTRY:
1511 break;
1512
1513 case elfcpp::R_386_32:
1514 if (should_apply_static_reloc(gsym, true, false, true))
1515 Relocate_functions<32, false>::rel32(view, object, psymval);
1516 break;
1517
1518 case elfcpp::R_386_PC32:
1519 {
1520 bool is_function_call = (gsym != NULL
1521 && gsym->type() == elfcpp::STT_FUNC);
1522 if (should_apply_static_reloc(gsym, false, is_function_call, true))
1523 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1524 }
1525 break;
1526
1527 case elfcpp::R_386_16:
1528 if (should_apply_static_reloc(gsym, true, false, false))
1529 Relocate_functions<32, false>::rel16(view, object, psymval);
1530 break;
1531
1532 case elfcpp::R_386_PC16:
1533 {
1534 bool is_function_call = (gsym != NULL
1535 && gsym->type() == elfcpp::STT_FUNC);
1536 if (should_apply_static_reloc(gsym, false, is_function_call, false))
1537 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1538 }
1539 break;
1540
1541 case elfcpp::R_386_8:
1542 if (should_apply_static_reloc(gsym, true, false, false))
1543 Relocate_functions<32, false>::rel8(view, object, psymval);
1544 break;
1545
1546 case elfcpp::R_386_PC8:
1547 {
1548 bool is_function_call = (gsym != NULL
1549 && gsym->type() == elfcpp::STT_FUNC);
1550 if (should_apply_static_reloc(gsym, false, is_function_call, false))
1551 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1552 }
1553 break;
1554
1555 case elfcpp::R_386_PLT32:
1556 gold_assert(gsym == NULL
1557 || gsym->has_plt_offset()
1558 || gsym->final_value_is_known());
1559 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1560 break;
1561
1562 case elfcpp::R_386_GOT32:
1563 gold_assert(have_got_offset);
1564 Relocate_functions<32, false>::rel32(view, got_offset);
1565 break;
1566
1567 case elfcpp::R_386_GOTOFF:
1568 {
1569 elfcpp::Elf_types<32>::Elf_Addr value;
1570 value = (psymval->value(object, 0)
1571 - target->got_plt_section()->address());
1572 Relocate_functions<32, false>::rel32(view, value);
1573 }
1574 break;
1575
1576 case elfcpp::R_386_GOTPC:
1577 {
1578 elfcpp::Elf_types<32>::Elf_Addr value;
1579 value = target->got_plt_section()->address();
1580 Relocate_functions<32, false>::pcrel32(view, value, address);
1581 }
1582 break;
1583
1584 case elfcpp::R_386_COPY:
1585 case elfcpp::R_386_GLOB_DAT:
1586 case elfcpp::R_386_JUMP_SLOT:
1587 case elfcpp::R_386_RELATIVE:
1588 // These are outstanding tls relocs, which are unexpected when
1589 // linking.
1590 case elfcpp::R_386_TLS_TPOFF:
1591 case elfcpp::R_386_TLS_DTPMOD32:
1592 case elfcpp::R_386_TLS_DTPOFF32:
1593 case elfcpp::R_386_TLS_TPOFF32:
1594 case elfcpp::R_386_TLS_DESC:
1595 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1596 _("unexpected reloc %u in object file"),
1597 r_type);
1598 break;
1599
1600 // These are initial tls relocs, which are expected when
1601 // linking.
1602 case elfcpp::R_386_TLS_GD: // Global-dynamic
1603 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1604 case elfcpp::R_386_TLS_DESC_CALL:
1605 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1606 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1607 case elfcpp::R_386_TLS_IE: // Initial-exec
1608 case elfcpp::R_386_TLS_IE_32:
1609 case elfcpp::R_386_TLS_GOTIE:
1610 case elfcpp::R_386_TLS_LE: // Local-exec
1611 case elfcpp::R_386_TLS_LE_32:
1612 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1613 view, address, view_size);
1614 break;
1615
1616 case elfcpp::R_386_32PLT:
1617 case elfcpp::R_386_TLS_GD_32:
1618 case elfcpp::R_386_TLS_GD_PUSH:
1619 case elfcpp::R_386_TLS_GD_CALL:
1620 case elfcpp::R_386_TLS_GD_POP:
1621 case elfcpp::R_386_TLS_LDM_32:
1622 case elfcpp::R_386_TLS_LDM_PUSH:
1623 case elfcpp::R_386_TLS_LDM_CALL:
1624 case elfcpp::R_386_TLS_LDM_POP:
1625 case elfcpp::R_386_USED_BY_INTEL_200:
1626 default:
1627 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1628 _("unsupported reloc %u"),
1629 r_type);
1630 break;
1631 }
1632
1633 return true;
1634 }
1635
1636 // Perform a TLS relocation.
1637
1638 inline void
1639 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1640 Target_i386* target,
1641 size_t relnum,
1642 const elfcpp::Rel<32, false>& rel,
1643 unsigned int r_type,
1644 const Sized_symbol<32>* gsym,
1645 const Symbol_value<32>* psymval,
1646 unsigned char* view,
1647 elfcpp::Elf_types<32>::Elf_Addr,
1648 off_t view_size)
1649 {
1650 Output_segment* tls_segment = relinfo->layout->tls_segment();
1651
1652 const Sized_relobj<32, false>* object = relinfo->object;
1653
1654 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1655
1656 const bool is_final = (gsym == NULL
1657 ? !parameters->output_is_position_independent()
1658 : gsym->final_value_is_known());
1659 const tls::Tls_optimization optimized_type
1660 = Target_i386::optimize_tls_reloc(is_final, r_type);
1661 switch (r_type)
1662 {
1663 case elfcpp::R_386_TLS_GD: // Global-dynamic
1664 if (optimized_type == tls::TLSOPT_TO_LE)
1665 {
1666 gold_assert(tls_segment != NULL);
1667 this->tls_gd_to_le(relinfo, relnum, tls_segment,
1668 rel, r_type, value, view,
1669 view_size);
1670 break;
1671 }
1672 else
1673 {
1674 unsigned int got_offset;
1675 if (gsym != NULL)
1676 {
1677 gold_assert(gsym->has_tls_got_offset(true));
1678 got_offset = gsym->tls_got_offset(true) - target->got_size();
1679 }
1680 else
1681 {
1682 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1683 gold_assert(object->local_has_tls_got_offset(r_sym, true));
1684 got_offset = (object->local_tls_got_offset(r_sym, true)
1685 - target->got_size());
1686 }
1687 if (optimized_type == tls::TLSOPT_TO_IE)
1688 {
1689 gold_assert(tls_segment != NULL);
1690 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1691 got_offset, view, view_size);
1692 break;
1693 }
1694 else if (optimized_type == tls::TLSOPT_NONE)
1695 {
1696 // Relocate the field with the offset of the pair of GOT
1697 // entries.
1698 Relocate_functions<32, false>::rel32(view, got_offset);
1699 break;
1700 }
1701 }
1702 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1703 _("unsupported reloc %u"),
1704 r_type);
1705 break;
1706
1707 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1708 case elfcpp::R_386_TLS_DESC_CALL:
1709 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1710 _("unsupported reloc %u"),
1711 r_type);
1712 break;
1713
1714 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1715 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1716 {
1717 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1718 _("both SUN and GNU model "
1719 "TLS relocations"));
1720 break;
1721 }
1722 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1723 if (optimized_type == tls::TLSOPT_TO_LE)
1724 {
1725 gold_assert(tls_segment != NULL);
1726 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1727 value, view, view_size);
1728 break;
1729 }
1730 else if (optimized_type == tls::TLSOPT_NONE)
1731 {
1732 // Relocate the field with the offset of the GOT entry for
1733 // the module index.
1734 unsigned int got_offset;
1735 if (gsym != NULL)
1736 {
1737 gold_assert(gsym->has_tls_got_offset(false));
1738 got_offset = gsym->tls_got_offset(false) - target->got_size();
1739 }
1740 else
1741 {
1742 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1743 gold_assert(object->local_has_tls_got_offset(r_sym, false));
1744 got_offset = (object->local_tls_got_offset(r_sym, false)
1745 - target->got_size());
1746 }
1747 Relocate_functions<32, false>::rel32(view, got_offset);
1748 break;
1749 }
1750 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1751 _("unsupported reloc %u"),
1752 r_type);
1753 break;
1754
1755 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1756 // This reloc can appear in debugging sections, in which case we
1757 // won't see the TLS_LDM reloc. The local_dynamic_type field
1758 // tells us this.
1759 gold_assert(tls_segment != NULL);
1760 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_GNU)
1761 value -= tls_segment->memsz();
1762 else if (optimized_type == tls::TLSOPT_TO_LE
1763 && this->local_dynamic_type_ != LOCAL_DYNAMIC_NONE)
1764 value = tls_segment->memsz() - value;
1765 Relocate_functions<32, false>::rel32(view, value);
1766 break;
1767
1768 case elfcpp::R_386_TLS_IE: // Initial-exec
1769 case elfcpp::R_386_TLS_GOTIE:
1770 case elfcpp::R_386_TLS_IE_32:
1771 if (optimized_type == tls::TLSOPT_TO_LE)
1772 {
1773 gold_assert(tls_segment != NULL);
1774 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1775 rel, r_type, value, view,
1776 view_size);
1777 break;
1778 }
1779 else if (optimized_type == tls::TLSOPT_NONE)
1780 {
1781 // Relocate the field with the offset of the GOT entry for
1782 // the tp-relative offset of the symbol.
1783 unsigned int got_offset;
1784 if (gsym != NULL)
1785 {
1786 gold_assert(gsym->has_got_offset());
1787 got_offset = gsym->got_offset();
1788 }
1789 else
1790 {
1791 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1792 gold_assert(object->local_has_got_offset(r_sym));
1793 got_offset = object->local_got_offset(r_sym);
1794 }
1795 // For the R_386_TLS_IE relocation, we need to apply the
1796 // absolute address of the GOT entry.
1797 if (r_type == elfcpp::R_386_TLS_IE)
1798 got_offset += target->got_plt_section()->address();
1799 // All GOT offsets are relative to the end of the GOT.
1800 got_offset -= target->got_size();
1801 Relocate_functions<32, false>::rel32(view, got_offset);
1802 break;
1803 }
1804 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1805 _("unsupported reloc %u"),
1806 r_type);
1807 break;
1808
1809 case elfcpp::R_386_TLS_LE: // Local-exec
1810 // If we're creating a shared library, a dynamic relocation will
1811 // have been created for this location, so do not apply it now.
1812 if (!parameters->output_is_shared())
1813 {
1814 gold_assert(tls_segment != NULL);
1815 value -= tls_segment->memsz();
1816 Relocate_functions<32, false>::rel32(view, value);
1817 }
1818 break;
1819
1820 case elfcpp::R_386_TLS_LE_32:
1821 // If we're creating a shared library, a dynamic relocation will
1822 // have been created for this location, so do not apply it now.
1823 if (!parameters->output_is_shared())
1824 {
1825 gold_assert(tls_segment != NULL);
1826 value = tls_segment->memsz() - value;
1827 Relocate_functions<32, false>::rel32(view, value);
1828 }
1829 break;
1830 }
1831 }
1832
1833 // Do a relocation in which we convert a TLS General-Dynamic to a
1834 // Local-Exec.
1835
1836 inline void
1837 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1838 size_t relnum,
1839 Output_segment* tls_segment,
1840 const elfcpp::Rel<32, false>& rel,
1841 unsigned int,
1842 elfcpp::Elf_types<32>::Elf_Addr value,
1843 unsigned char* view,
1844 off_t view_size)
1845 {
1846 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1847 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1848 // leal foo(%reg),%eax; call ___tls_get_addr
1849 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1850
1851 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1852 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1853
1854 unsigned char op1 = view[-1];
1855 unsigned char op2 = view[-2];
1856
1857 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1858 op2 == 0x8d || op2 == 0x04);
1859 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1860
1861 int roff = 5;
1862
1863 if (op2 == 0x04)
1864 {
1865 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1866 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1867 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1868 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1869 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1870 }
1871 else
1872 {
1873 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1874 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1875 if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1876 && view[9] == 0x90)
1877 {
1878 // There is a trailing nop. Use the size byte subl.
1879 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1880 roff = 6;
1881 }
1882 else
1883 {
1884 // Use the five byte subl.
1885 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1886 }
1887 }
1888
1889 value = tls_segment->memsz() - value;
1890 Relocate_functions<32, false>::rel32(view + roff, value);
1891
1892 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1893 // We can skip it.
1894 this->skip_call_tls_get_addr_ = true;
1895 }
1896
1897 // Do a relocation in which we convert a TLS General-Dynamic to an
1898 // Initial-Exec.
1899
1900 inline void
1901 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
1902 size_t relnum,
1903 Output_segment* tls_segment,
1904 const elfcpp::Rel<32, false>& rel,
1905 unsigned int,
1906 elfcpp::Elf_types<32>::Elf_Addr value,
1907 unsigned char* view,
1908 off_t view_size)
1909 {
1910 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
1911 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
1912
1913 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1914 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1915
1916 unsigned char op1 = view[-1];
1917 unsigned char op2 = view[-2];
1918
1919 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1920 op2 == 0x8d || op2 == 0x04);
1921 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1922
1923 int roff = 5;
1924
1925 // FIXME: For now, support only one form.
1926 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1927 op1 == 0x8d && op2 == 0x04);
1928
1929 if (op2 == 0x04)
1930 {
1931 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1932 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1933 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1934 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1935 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
1936 }
1937 else
1938 {
1939 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1940 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1941 if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1942 && view[9] == 0x90)
1943 {
1944 // FIXME: This is not the right instruction sequence.
1945 // There is a trailing nop. Use the size byte subl.
1946 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1947 roff = 6;
1948 }
1949 else
1950 {
1951 // FIXME: This is not the right instruction sequence.
1952 // Use the five byte subl.
1953 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1954 }
1955 }
1956
1957 value = tls_segment->memsz() - value;
1958 Relocate_functions<32, false>::rel32(view + roff, value);
1959
1960 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1961 // We can skip it.
1962 this->skip_call_tls_get_addr_ = true;
1963 }
1964
1965 // Do a relocation in which we convert a TLS Local-Dynamic to a
1966 // Local-Exec.
1967
1968 inline void
1969 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
1970 size_t relnum,
1971 Output_segment*,
1972 const elfcpp::Rel<32, false>& rel,
1973 unsigned int,
1974 elfcpp::Elf_types<32>::Elf_Addr,
1975 unsigned char* view,
1976 off_t view_size)
1977 {
1978 // leal foo(%reg), %eax; call ___tls_get_addr
1979 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1980
1981 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1982 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1983
1984 // FIXME: Does this test really always pass?
1985 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1986 view[-2] == 0x8d && view[-1] == 0x83);
1987
1988 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1989
1990 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1991
1992 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1993 // We can skip it.
1994 this->skip_call_tls_get_addr_ = true;
1995 }
1996
1997 // Do a relocation in which we convert a TLS Initial-Exec to a
1998 // Local-Exec.
1999
2000 inline void
2001 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2002 size_t relnum,
2003 Output_segment* tls_segment,
2004 const elfcpp::Rel<32, false>& rel,
2005 unsigned int r_type,
2006 elfcpp::Elf_types<32>::Elf_Addr value,
2007 unsigned char* view,
2008 off_t view_size)
2009 {
2010 // We have to actually change the instructions, which means that we
2011 // need to examine the opcodes to figure out which instruction we
2012 // are looking at.
2013 if (r_type == elfcpp::R_386_TLS_IE)
2014 {
2015 // movl %gs:XX,%eax ==> movl $YY,%eax
2016 // movl %gs:XX,%reg ==> movl $YY,%reg
2017 // addl %gs:XX,%reg ==> addl $YY,%reg
2018 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2019 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2020
2021 unsigned char op1 = view[-1];
2022 if (op1 == 0xa1)
2023 {
2024 // movl XX,%eax ==> movl $YY,%eax
2025 view[-1] = 0xb8;
2026 }
2027 else
2028 {
2029 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2030
2031 unsigned char op2 = view[-2];
2032 if (op2 == 0x8b)
2033 {
2034 // movl XX,%reg ==> movl $YY,%reg
2035 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2036 (op1 & 0xc7) == 0x05);
2037 view[-2] = 0xc7;
2038 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2039 }
2040 else if (op2 == 0x03)
2041 {
2042 // addl XX,%reg ==> addl $YY,%reg
2043 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2044 (op1 & 0xc7) == 0x05);
2045 view[-2] = 0x81;
2046 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2047 }
2048 else
2049 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2050 }
2051 }
2052 else
2053 {
2054 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2055 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2056 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2057 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2058 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2059
2060 unsigned char op1 = view[-1];
2061 unsigned char op2 = view[-2];
2062 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2063 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2064 if (op2 == 0x8b)
2065 {
2066 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2067 view[-2] = 0xc7;
2068 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2069 }
2070 else if (op2 == 0x2b)
2071 {
2072 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2073 view[-2] = 0x81;
2074 view[-1] = 0xe8 | ((op1 >> 3) & 7);
2075 }
2076 else if (op2 == 0x03)
2077 {
2078 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2079 view[-2] = 0x81;
2080 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2081 }
2082 else
2083 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2084 }
2085
2086 value = tls_segment->memsz() - value;
2087 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2088 value = - value;
2089
2090 Relocate_functions<32, false>::rel32(view, value);
2091 }
2092
2093 // Relocate section data.
2094
2095 void
2096 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2097 unsigned int sh_type,
2098 const unsigned char* prelocs,
2099 size_t reloc_count,
2100 Output_section* output_section,
2101 bool needs_special_offset_handling,
2102 unsigned char* view,
2103 elfcpp::Elf_types<32>::Elf_Addr address,
2104 off_t view_size)
2105 {
2106 gold_assert(sh_type == elfcpp::SHT_REL);
2107
2108 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2109 Target_i386::Relocate>(
2110 relinfo,
2111 this,
2112 prelocs,
2113 reloc_count,
2114 output_section,
2115 needs_special_offset_handling,
2116 view,
2117 address,
2118 view_size);
2119 }
2120
2121 // Return the value to use for a dynamic which requires special
2122 // treatment. This is how we support equality comparisons of function
2123 // pointers across shared library boundaries, as described in the
2124 // processor specific ABI supplement.
2125
2126 uint64_t
2127 Target_i386::do_dynsym_value(const Symbol* gsym) const
2128 {
2129 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2130 return this->plt_section()->address() + gsym->plt_offset();
2131 }
2132
2133 // Return a string used to fill a code section with nops to take up
2134 // the specified length.
2135
2136 std::string
2137 Target_i386::do_code_fill(off_t length)
2138 {
2139 if (length >= 16)
2140 {
2141 // Build a jmp instruction to skip over the bytes.
2142 unsigned char jmp[5];
2143 jmp[0] = 0xe9;
2144 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2145 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2146 + std::string(length - 5, '\0'));
2147 }
2148
2149 // Nop sequences of various lengths.
2150 const char nop1[1] = { 0x90 }; // nop
2151 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
2152 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
2153 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
2154 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
2155 0x00 }; // leal 0(%esi,1),%esi
2156 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2157 0x00, 0x00 };
2158 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2159 0x00, 0x00, 0x00 };
2160 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
2161 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2162 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
2163 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
2164 0x00 };
2165 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2166 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2167 0x00, 0x00 };
2168 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2169 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2170 0x00, 0x00, 0x00 };
2171 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2172 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2173 0x00, 0x00, 0x00, 0x00 };
2174 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2175 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2176 0x27, 0x00, 0x00, 0x00,
2177 0x00 };
2178 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2179 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2180 0xbc, 0x27, 0x00, 0x00,
2181 0x00, 0x00 };
2182 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2183 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2184 0x90, 0x90, 0x90, 0x90,
2185 0x90, 0x90, 0x90 };
2186
2187 const char* nops[16] = {
2188 NULL,
2189 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2190 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2191 };
2192
2193 return std::string(nops[length], length);
2194 }
2195
2196 // The selector for i386 object files.
2197
2198 class Target_selector_i386 : public Target_selector
2199 {
2200 public:
2201 Target_selector_i386()
2202 : Target_selector(elfcpp::EM_386, 32, false)
2203 { }
2204
2205 Target*
2206 recognize(int machine, int osabi, int abiversion);
2207
2208 private:
2209 Target_i386* target_;
2210 };
2211
2212 // Recognize an i386 object file when we already know that the machine
2213 // number is EM_386.
2214
2215 Target*
2216 Target_selector_i386::recognize(int, int, int)
2217 {
2218 if (this->target_ == NULL)
2219 this->target_ = new Target_i386();
2220 return this->target_;
2221 }
2222
2223 Target_selector_i386 target_selector_i386;
2224
2225 } // End anonymous namespace.