Add -Wshadow to the gcc command line options used when compiling the binutils.
[binutils.git] / gold / i386.cc
blobcadffbadbca541a7d0e96f928614a02a281fce17
1 // i386.cc -- i386 target support for gold.
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 #include "gold.h"
25 #include <cstring>
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 "copy-relocs.h"
36 #include "target.h"
37 #include "target-reloc.h"
38 #include "target-select.h"
39 #include "tls.h"
40 #include "freebsd.h"
41 #include "gc.h"
43 namespace
46 using namespace gold;
48 class Output_data_plt_i386;
50 // The i386 target class.
51 // TLS info comes from
52 // http://people.redhat.com/drepper/tls.pdf
53 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
55 class Target_i386 : public Target_freebsd<32, false>
57 public:
58 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
60 Target_i386()
61 : Target_freebsd<32, false>(&i386_info),
62 got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
63 copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
64 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
65 { }
67 // Process the relocations to determine unreferenced sections for
68 // garbage collection.
69 void
70 gc_process_relocs(Symbol_table* symtab,
71 Layout* layout,
72 Sized_relobj<32, false>* object,
73 unsigned int data_shndx,
74 unsigned int sh_type,
75 const unsigned char* prelocs,
76 size_t reloc_count,
77 Output_section* output_section,
78 bool needs_special_offset_handling,
79 size_t local_symbol_count,
80 const unsigned char* plocal_symbols);
82 // Scan the relocations to look for symbol adjustments.
83 void
84 scan_relocs(Symbol_table* symtab,
85 Layout* layout,
86 Sized_relobj<32, false>* object,
87 unsigned int data_shndx,
88 unsigned int sh_type,
89 const unsigned char* prelocs,
90 size_t reloc_count,
91 Output_section* output_section,
92 bool needs_special_offset_handling,
93 size_t local_symbol_count,
94 const unsigned char* plocal_symbols);
96 // Finalize the sections.
97 void
98 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
100 // Return the value to use for a dynamic which requires special
101 // treatment.
102 uint64_t
103 do_dynsym_value(const Symbol*) const;
105 // Relocate a section.
106 void
107 relocate_section(const Relocate_info<32, false>*,
108 unsigned int sh_type,
109 const unsigned char* prelocs,
110 size_t reloc_count,
111 Output_section* output_section,
112 bool needs_special_offset_handling,
113 unsigned char* view,
114 elfcpp::Elf_types<32>::Elf_Addr view_address,
115 section_size_type view_size,
116 const Reloc_symbol_changes*);
118 // Scan the relocs during a relocatable link.
119 void
120 scan_relocatable_relocs(Symbol_table* symtab,
121 Layout* layout,
122 Sized_relobj<32, false>* object,
123 unsigned int data_shndx,
124 unsigned int sh_type,
125 const unsigned char* prelocs,
126 size_t reloc_count,
127 Output_section* output_section,
128 bool needs_special_offset_handling,
129 size_t local_symbol_count,
130 const unsigned char* plocal_symbols,
131 Relocatable_relocs*);
133 // Relocate a section during a relocatable link.
134 void
135 relocate_for_relocatable(const Relocate_info<32, false>*,
136 unsigned int sh_type,
137 const unsigned char* prelocs,
138 size_t reloc_count,
139 Output_section* output_section,
140 off_t offset_in_output_section,
141 const Relocatable_relocs*,
142 unsigned char* view,
143 elfcpp::Elf_types<32>::Elf_Addr view_address,
144 section_size_type view_size,
145 unsigned char* reloc_view,
146 section_size_type reloc_view_size);
148 // Return a string used to fill a code section with nops.
149 std::string
150 do_code_fill(section_size_type length) const;
152 // Return whether SYM is defined by the ABI.
153 bool
154 do_is_defined_by_abi(const Symbol* sym) const
155 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
157 // Return whether a symbol name implies a local label. The UnixWare
158 // 2.1 cc generates temporary symbols that start with .X, so we
159 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
160 // If so, we should move the .X recognition into
161 // Target::do_is_local_label_name.
162 bool
163 do_is_local_label_name(const char* name) const
165 if (name[0] == '.' && name[1] == 'X')
166 return true;
167 return Target::do_is_local_label_name(name);
170 // Adjust -fstack-split code which calls non-stack-split code.
171 void
172 do_calls_non_split(Relobj* object, unsigned int shndx,
173 section_offset_type fnoffset, section_size_type fnsize,
174 unsigned char* view, section_size_type view_size,
175 std::string* from, std::string* to) const;
177 // Return the size of the GOT section.
178 section_size_type
179 got_size()
181 gold_assert(this->got_ != NULL);
182 return this->got_->data_size();
185 private:
186 // The class which scans relocations.
187 struct Scan
189 inline void
190 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
191 Sized_relobj<32, false>* object,
192 unsigned int data_shndx,
193 Output_section* output_section,
194 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
195 const elfcpp::Sym<32, false>& lsym);
197 inline void
198 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
199 Sized_relobj<32, false>* object,
200 unsigned int data_shndx,
201 Output_section* output_section,
202 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
203 Symbol* gsym);
205 static void
206 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
208 static void
209 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
210 Symbol*);
213 // The class which implements relocation.
214 class Relocate
216 public:
217 Relocate()
218 : skip_call_tls_get_addr_(false),
219 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
222 ~Relocate()
224 if (this->skip_call_tls_get_addr_)
226 // FIXME: This needs to specify the location somehow.
227 gold_error(_("missing expected TLS relocation"));
231 // Return whether the static relocation needs to be applied.
232 inline bool
233 should_apply_static_reloc(const Sized_symbol<32>* gsym,
234 int ref_flags,
235 bool is_32bit,
236 Output_section* output_section);
238 // Do a relocation. Return false if the caller should not issue
239 // any warnings about this relocation.
240 inline bool
241 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
242 size_t relnum, const elfcpp::Rel<32, false>&,
243 unsigned int r_type, const Sized_symbol<32>*,
244 const Symbol_value<32>*,
245 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
246 section_size_type);
248 private:
249 // Do a TLS relocation.
250 inline void
251 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
252 size_t relnum, const elfcpp::Rel<32, false>&,
253 unsigned int r_type, const Sized_symbol<32>*,
254 const Symbol_value<32>*,
255 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
256 section_size_type);
258 // Do a TLS General-Dynamic to Initial-Exec transition.
259 inline void
260 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
261 Output_segment* tls_segment,
262 const elfcpp::Rel<32, false>&, unsigned int r_type,
263 elfcpp::Elf_types<32>::Elf_Addr value,
264 unsigned char* view,
265 section_size_type view_size);
267 // Do a TLS General-Dynamic to Local-Exec transition.
268 inline void
269 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
270 Output_segment* tls_segment,
271 const elfcpp::Rel<32, false>&, unsigned int r_type,
272 elfcpp::Elf_types<32>::Elf_Addr value,
273 unsigned char* view,
274 section_size_type view_size);
276 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
277 // transition.
278 inline void
279 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
280 Output_segment* tls_segment,
281 const elfcpp::Rel<32, false>&, unsigned int r_type,
282 elfcpp::Elf_types<32>::Elf_Addr value,
283 unsigned char* view,
284 section_size_type view_size);
286 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
287 // transition.
288 inline void
289 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
290 Output_segment* tls_segment,
291 const elfcpp::Rel<32, false>&, unsigned int r_type,
292 elfcpp::Elf_types<32>::Elf_Addr value,
293 unsigned char* view,
294 section_size_type view_size);
296 // Do a TLS Local-Dynamic to Local-Exec transition.
297 inline void
298 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
299 Output_segment* tls_segment,
300 const elfcpp::Rel<32, false>&, unsigned int r_type,
301 elfcpp::Elf_types<32>::Elf_Addr value,
302 unsigned char* view,
303 section_size_type view_size);
305 // Do a TLS Initial-Exec to Local-Exec transition.
306 static inline void
307 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
308 Output_segment* tls_segment,
309 const elfcpp::Rel<32, false>&, unsigned int r_type,
310 elfcpp::Elf_types<32>::Elf_Addr value,
311 unsigned char* view,
312 section_size_type view_size);
314 // We need to keep track of which type of local dynamic relocation
315 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
316 enum Local_dynamic_type
318 LOCAL_DYNAMIC_NONE,
319 LOCAL_DYNAMIC_SUN,
320 LOCAL_DYNAMIC_GNU
323 // This is set if we should skip the next reloc, which should be a
324 // PLT32 reloc against ___tls_get_addr.
325 bool skip_call_tls_get_addr_;
326 // The type of local dynamic relocation we have seen in the section
327 // being relocated, if any.
328 Local_dynamic_type local_dynamic_type_;
331 // A class which returns the size required for a relocation type,
332 // used while scanning relocs during a relocatable link.
333 class Relocatable_size_for_reloc
335 public:
336 unsigned int
337 get_size_for_reloc(unsigned int, Relobj*);
340 // Adjust TLS relocation type based on the options and whether this
341 // is a local symbol.
342 static tls::Tls_optimization
343 optimize_tls_reloc(bool is_final, int r_type);
345 // Get the GOT section, creating it if necessary.
346 Output_data_got<32, false>*
347 got_section(Symbol_table*, Layout*);
349 // Get the GOT PLT section.
350 Output_data_space*
351 got_plt_section() const
353 gold_assert(this->got_plt_ != NULL);
354 return this->got_plt_;
357 // Create a PLT entry for a global symbol.
358 void
359 make_plt_entry(Symbol_table*, Layout*, Symbol*);
361 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
362 void
363 define_tls_base_symbol(Symbol_table*, Layout*);
365 // Create a GOT entry for the TLS module index.
366 unsigned int
367 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
368 Sized_relobj<32, false>* object);
370 // Get the PLT section.
371 const Output_data_plt_i386*
372 plt_section() const
374 gold_assert(this->plt_ != NULL);
375 return this->plt_;
378 // Get the dynamic reloc section, creating it if necessary.
379 Reloc_section*
380 rel_dyn_section(Layout*);
382 // Add a potential copy relocation.
383 void
384 copy_reloc(Symbol_table* symtab, Layout* layout,
385 Sized_relobj<32, false>* object,
386 unsigned int shndx, Output_section* output_section,
387 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
389 this->copy_relocs_.copy_reloc(symtab, layout,
390 symtab->get_sized_symbol<32>(sym),
391 object, shndx, output_section, reloc,
392 this->rel_dyn_section(layout));
395 // Information about this specific target which we pass to the
396 // general Target structure.
397 static const Target::Target_info i386_info;
399 // The types of GOT entries needed for this platform.
400 enum Got_type
402 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
403 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
404 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
405 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
406 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
409 // The GOT section.
410 Output_data_got<32, false>* got_;
411 // The PLT section.
412 Output_data_plt_i386* plt_;
413 // The GOT PLT section.
414 Output_data_space* got_plt_;
415 // The dynamic reloc section.
416 Reloc_section* rel_dyn_;
417 // Relocs saved to avoid a COPY reloc.
418 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
419 // Space for variables copied with a COPY reloc.
420 Output_data_space* dynbss_;
421 // Offset of the GOT entry for the TLS module index.
422 unsigned int got_mod_index_offset_;
423 // True if the _TLS_MODULE_BASE_ symbol has been defined.
424 bool tls_base_symbol_defined_;
427 const Target::Target_info Target_i386::i386_info =
429 32, // size
430 false, // is_big_endian
431 elfcpp::EM_386, // machine_code
432 false, // has_make_symbol
433 false, // has_resolve
434 true, // has_code_fill
435 true, // is_default_stack_executable
436 '\0', // wrap_char
437 "/usr/lib/libc.so.1", // dynamic_linker
438 0x08048000, // default_text_segment_address
439 0x1000, // abi_pagesize (overridable by -z max-page-size)
440 0x1000, // common_pagesize (overridable by -z common-page-size)
441 elfcpp::SHN_UNDEF, // small_common_shndx
442 elfcpp::SHN_UNDEF, // large_common_shndx
443 0, // small_common_section_flags
444 0, // large_common_section_flags
445 NULL, // attributes_section
446 NULL // attributes_vendor
449 // Get the GOT section, creating it if necessary.
451 Output_data_got<32, false>*
452 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
454 if (this->got_ == NULL)
456 gold_assert(symtab != NULL && layout != NULL);
458 this->got_ = new Output_data_got<32, false>();
460 Output_section* os;
461 os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
462 (elfcpp::SHF_ALLOC
463 | elfcpp::SHF_WRITE),
464 this->got_, false);
465 os->set_is_relro();
467 // The old GNU linker creates a .got.plt section. We just
468 // create another set of data in the .got section. Note that we
469 // always create a PLT if we create a GOT, although the PLT
470 // might be empty.
471 this->got_plt_ = new Output_data_space(4, "** GOT PLT");
472 os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
473 (elfcpp::SHF_ALLOC
474 | elfcpp::SHF_WRITE),
475 this->got_plt_, false);
476 os->set_is_relro();
478 // The first three entries are reserved.
479 this->got_plt_->set_current_data_size(3 * 4);
481 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
482 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
483 this->got_plt_,
484 0, 0, elfcpp::STT_OBJECT,
485 elfcpp::STB_LOCAL,
486 elfcpp::STV_HIDDEN, 0,
487 false, false);
490 return this->got_;
493 // Get the dynamic reloc section, creating it if necessary.
495 Target_i386::Reloc_section*
496 Target_i386::rel_dyn_section(Layout* layout)
498 if (this->rel_dyn_ == NULL)
500 gold_assert(layout != NULL);
501 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
502 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
503 elfcpp::SHF_ALLOC, this->rel_dyn_, true);
505 return this->rel_dyn_;
508 // A class to handle the PLT data.
510 class Output_data_plt_i386 : public Output_section_data
512 public:
513 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
515 Output_data_plt_i386(Layout*, Output_data_space*);
517 // Add an entry to the PLT.
518 void
519 add_entry(Symbol* gsym);
521 // Return the .rel.plt section data.
522 const Reloc_section*
523 rel_plt() const
524 { return this->rel_; }
526 protected:
527 void
528 do_adjust_output_section(Output_section* os);
530 // Write to a map file.
531 void
532 do_print_to_mapfile(Mapfile* mapfile) const
533 { mapfile->print_output_data(this, _("** PLT")); }
535 private:
536 // The size of an entry in the PLT.
537 static const int plt_entry_size = 16;
539 // The first entry in the PLT for an executable.
540 static unsigned char exec_first_plt_entry[plt_entry_size];
542 // The first entry in the PLT for a shared object.
543 static unsigned char dyn_first_plt_entry[plt_entry_size];
545 // Other entries in the PLT for an executable.
546 static unsigned char exec_plt_entry[plt_entry_size];
548 // Other entries in the PLT for a shared object.
549 static unsigned char dyn_plt_entry[plt_entry_size];
551 // Set the final size.
552 void
553 set_final_data_size()
554 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
556 // Write out the PLT data.
557 void
558 do_write(Output_file*);
560 // The reloc section.
561 Reloc_section* rel_;
562 // The .got.plt section.
563 Output_data_space* got_plt_;
564 // The number of PLT entries.
565 unsigned int count_;
568 // Create the PLT section. The ordinary .got section is an argument,
569 // since we need to refer to the start. We also create our own .got
570 // section just for PLT entries.
572 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
573 Output_data_space* got_plt)
574 : Output_section_data(4), got_plt_(got_plt), count_(0)
576 this->rel_ = new Reloc_section(false);
577 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
578 elfcpp::SHF_ALLOC, this->rel_, true);
581 void
582 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
584 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
585 // linker, and so do we.
586 os->set_entsize(4);
589 // Add an entry to the PLT.
591 void
592 Output_data_plt_i386::add_entry(Symbol* gsym)
594 gold_assert(!gsym->has_plt_offset());
596 // Note that when setting the PLT offset we skip the initial
597 // reserved PLT entry.
598 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
600 ++this->count_;
602 section_offset_type got_offset = this->got_plt_->current_data_size();
604 // Every PLT entry needs a GOT entry which points back to the PLT
605 // entry (this will be changed by the dynamic linker, normally
606 // lazily when the function is called).
607 this->got_plt_->set_current_data_size(got_offset + 4);
609 // Every PLT entry needs a reloc.
610 gsym->set_needs_dynsym_entry();
611 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
612 got_offset);
614 // Note that we don't need to save the symbol. The contents of the
615 // PLT are independent of which symbols are used. The symbols only
616 // appear in the relocations.
619 // The first entry in the PLT for an executable.
621 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
623 0xff, 0x35, // pushl contents of memory address
624 0, 0, 0, 0, // replaced with address of .got + 4
625 0xff, 0x25, // jmp indirect
626 0, 0, 0, 0, // replaced with address of .got + 8
627 0, 0, 0, 0 // unused
630 // The first entry in the PLT for a shared object.
632 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
634 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
635 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
636 0, 0, 0, 0 // unused
639 // Subsequent entries in the PLT for an executable.
641 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
643 0xff, 0x25, // jmp indirect
644 0, 0, 0, 0, // replaced with address of symbol in .got
645 0x68, // pushl immediate
646 0, 0, 0, 0, // replaced with offset into relocation table
647 0xe9, // jmp relative
648 0, 0, 0, 0 // replaced with offset to start of .plt
651 // Subsequent entries in the PLT for a shared object.
653 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
655 0xff, 0xa3, // jmp *offset(%ebx)
656 0, 0, 0, 0, // replaced with offset of symbol in .got
657 0x68, // pushl immediate
658 0, 0, 0, 0, // replaced with offset into relocation table
659 0xe9, // jmp relative
660 0, 0, 0, 0 // replaced with offset to start of .plt
663 // Write out the PLT. This uses the hand-coded instructions above,
664 // and adjusts them as needed. This is all specified by the i386 ELF
665 // Processor Supplement.
667 void
668 Output_data_plt_i386::do_write(Output_file* of)
670 const off_t off = this->offset();
671 const section_size_type oview_size =
672 convert_to_section_size_type(this->data_size());
673 unsigned char* const oview = of->get_output_view(off, oview_size);
675 const off_t got_file_offset = this->got_plt_->offset();
676 const section_size_type got_size =
677 convert_to_section_size_type(this->got_plt_->data_size());
678 unsigned char* const got_view = of->get_output_view(got_file_offset,
679 got_size);
681 unsigned char* pov = oview;
683 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
684 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
686 if (parameters->options().output_is_position_independent())
687 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
688 else
690 memcpy(pov, exec_first_plt_entry, plt_entry_size);
691 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
692 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
694 pov += plt_entry_size;
696 unsigned char* got_pov = got_view;
698 memset(got_pov, 0, 12);
699 got_pov += 12;
701 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
703 unsigned int plt_offset = plt_entry_size;
704 unsigned int plt_rel_offset = 0;
705 unsigned int got_offset = 12;
706 const unsigned int count = this->count_;
707 for (unsigned int i = 0;
708 i < count;
709 ++i,
710 pov += plt_entry_size,
711 got_pov += 4,
712 plt_offset += plt_entry_size,
713 plt_rel_offset += rel_size,
714 got_offset += 4)
716 // Set and adjust the PLT entry itself.
718 if (parameters->options().output_is_position_independent())
720 memcpy(pov, dyn_plt_entry, plt_entry_size);
721 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
723 else
725 memcpy(pov, exec_plt_entry, plt_entry_size);
726 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
727 (got_address
728 + got_offset));
731 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
732 elfcpp::Swap<32, false>::writeval(pov + 12,
733 - (plt_offset + plt_entry_size));
735 // Set the entry in the GOT.
736 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
739 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
740 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
742 of->write_output_view(off, oview_size, oview);
743 of->write_output_view(got_file_offset, got_size, got_view);
746 // Create a PLT entry for a global symbol.
748 void
749 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
751 if (gsym->has_plt_offset())
752 return;
754 if (this->plt_ == NULL)
756 // Create the GOT sections first.
757 this->got_section(symtab, layout);
759 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
760 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
761 (elfcpp::SHF_ALLOC
762 | elfcpp::SHF_EXECINSTR),
763 this->plt_, false);
766 this->plt_->add_entry(gsym);
769 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
771 void
772 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
774 if (this->tls_base_symbol_defined_)
775 return;
777 Output_segment* tls_segment = layout->tls_segment();
778 if (tls_segment != NULL)
780 bool is_exec = parameters->options().output_is_executable();
781 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
782 tls_segment, 0, 0,
783 elfcpp::STT_TLS,
784 elfcpp::STB_LOCAL,
785 elfcpp::STV_HIDDEN, 0,
786 (is_exec
787 ? Symbol::SEGMENT_END
788 : Symbol::SEGMENT_START),
789 true);
791 this->tls_base_symbol_defined_ = true;
794 // Create a GOT entry for the TLS module index.
796 unsigned int
797 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
798 Sized_relobj<32, false>* object)
800 if (this->got_mod_index_offset_ == -1U)
802 gold_assert(symtab != NULL && layout != NULL && object != NULL);
803 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
804 Output_data_got<32, false>* got = this->got_section(symtab, layout);
805 unsigned int got_offset = got->add_constant(0);
806 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
807 got_offset);
808 got->add_constant(0);
809 this->got_mod_index_offset_ = got_offset;
811 return this->got_mod_index_offset_;
814 // Optimize the TLS relocation type based on what we know about the
815 // symbol. IS_FINAL is true if the final address of this symbol is
816 // known at link time.
818 tls::Tls_optimization
819 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
821 // If we are generating a shared library, then we can't do anything
822 // in the linker.
823 if (parameters->options().shared())
824 return tls::TLSOPT_NONE;
826 switch (r_type)
828 case elfcpp::R_386_TLS_GD:
829 case elfcpp::R_386_TLS_GOTDESC:
830 case elfcpp::R_386_TLS_DESC_CALL:
831 // These are General-Dynamic which permits fully general TLS
832 // access. Since we know that we are generating an executable,
833 // we can convert this to Initial-Exec. If we also know that
834 // this is a local symbol, we can further switch to Local-Exec.
835 if (is_final)
836 return tls::TLSOPT_TO_LE;
837 return tls::TLSOPT_TO_IE;
839 case elfcpp::R_386_TLS_LDM:
840 // This is Local-Dynamic, which refers to a local symbol in the
841 // dynamic TLS block. Since we know that we generating an
842 // executable, we can switch to Local-Exec.
843 return tls::TLSOPT_TO_LE;
845 case elfcpp::R_386_TLS_LDO_32:
846 // Another type of Local-Dynamic relocation.
847 return tls::TLSOPT_TO_LE;
849 case elfcpp::R_386_TLS_IE:
850 case elfcpp::R_386_TLS_GOTIE:
851 case elfcpp::R_386_TLS_IE_32:
852 // These are Initial-Exec relocs which get the thread offset
853 // from the GOT. If we know that we are linking against the
854 // local symbol, we can switch to Local-Exec, which links the
855 // thread offset into the instruction.
856 if (is_final)
857 return tls::TLSOPT_TO_LE;
858 return tls::TLSOPT_NONE;
860 case elfcpp::R_386_TLS_LE:
861 case elfcpp::R_386_TLS_LE_32:
862 // When we already have Local-Exec, there is nothing further we
863 // can do.
864 return tls::TLSOPT_NONE;
866 default:
867 gold_unreachable();
871 // Report an unsupported relocation against a local symbol.
873 void
874 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
875 unsigned int r_type)
877 gold_error(_("%s: unsupported reloc %u against local symbol"),
878 object->name().c_str(), r_type);
881 // Scan a relocation for a local symbol.
883 inline void
884 Target_i386::Scan::local(Symbol_table* symtab,
885 Layout* layout,
886 Target_i386* target,
887 Sized_relobj<32, false>* object,
888 unsigned int data_shndx,
889 Output_section* output_section,
890 const elfcpp::Rel<32, false>& reloc,
891 unsigned int r_type,
892 const elfcpp::Sym<32, false>& lsym)
894 switch (r_type)
896 case elfcpp::R_386_NONE:
897 case elfcpp::R_386_GNU_VTINHERIT:
898 case elfcpp::R_386_GNU_VTENTRY:
899 break;
901 case elfcpp::R_386_32:
902 // If building a shared library (or a position-independent
903 // executable), we need to create a dynamic relocation for
904 // this location. The relocation applied at link time will
905 // apply the link-time value, so we flag the location with
906 // an R_386_RELATIVE relocation so the dynamic loader can
907 // relocate it easily.
908 if (parameters->options().output_is_position_independent())
910 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
911 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
912 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
913 output_section, data_shndx,
914 reloc.get_r_offset());
916 break;
918 case elfcpp::R_386_16:
919 case elfcpp::R_386_8:
920 // If building a shared library (or a position-independent
921 // executable), we need to create a dynamic relocation for
922 // this location. Because the addend needs to remain in the
923 // data section, we need to be careful not to apply this
924 // relocation statically.
925 if (parameters->options().output_is_position_independent())
927 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
928 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
929 if (lsym.get_st_type() != elfcpp::STT_SECTION)
930 rel_dyn->add_local(object, r_sym, r_type, output_section,
931 data_shndx, reloc.get_r_offset());
932 else
934 gold_assert(lsym.get_st_value() == 0);
935 unsigned int shndx = lsym.get_st_shndx();
936 bool is_ordinary;
937 shndx = object->adjust_sym_shndx(r_sym, shndx,
938 &is_ordinary);
939 if (!is_ordinary)
940 object->error(_("section symbol %u has bad shndx %u"),
941 r_sym, shndx);
942 else
943 rel_dyn->add_local_section(object, shndx,
944 r_type, output_section,
945 data_shndx, reloc.get_r_offset());
948 break;
950 case elfcpp::R_386_PC32:
951 case elfcpp::R_386_PC16:
952 case elfcpp::R_386_PC8:
953 break;
955 case elfcpp::R_386_PLT32:
956 // Since we know this is a local symbol, we can handle this as a
957 // PC32 reloc.
958 break;
960 case elfcpp::R_386_GOTOFF:
961 case elfcpp::R_386_GOTPC:
962 // We need a GOT section.
963 target->got_section(symtab, layout);
964 break;
966 case elfcpp::R_386_GOT32:
968 // The symbol requires a GOT entry.
969 Output_data_got<32, false>* got = target->got_section(symtab, layout);
970 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
971 if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
973 // If we are generating a shared object, we need to add a
974 // dynamic RELATIVE relocation for this symbol's GOT entry.
975 if (parameters->options().output_is_position_independent())
977 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
978 r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
979 rel_dyn->add_local_relative(
980 object, r_sym, elfcpp::R_386_RELATIVE, got,
981 object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
985 break;
987 // These are relocations which should only be seen by the
988 // dynamic linker, and should never be seen here.
989 case elfcpp::R_386_COPY:
990 case elfcpp::R_386_GLOB_DAT:
991 case elfcpp::R_386_JUMP_SLOT:
992 case elfcpp::R_386_RELATIVE:
993 case elfcpp::R_386_TLS_TPOFF:
994 case elfcpp::R_386_TLS_DTPMOD32:
995 case elfcpp::R_386_TLS_DTPOFF32:
996 case elfcpp::R_386_TLS_TPOFF32:
997 case elfcpp::R_386_TLS_DESC:
998 gold_error(_("%s: unexpected reloc %u in object file"),
999 object->name().c_str(), r_type);
1000 break;
1002 // These are initial TLS relocs, which are expected when
1003 // linking.
1004 case elfcpp::R_386_TLS_GD: // Global-dynamic
1005 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1006 case elfcpp::R_386_TLS_DESC_CALL:
1007 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1008 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1009 case elfcpp::R_386_TLS_IE: // Initial-exec
1010 case elfcpp::R_386_TLS_IE_32:
1011 case elfcpp::R_386_TLS_GOTIE:
1012 case elfcpp::R_386_TLS_LE: // Local-exec
1013 case elfcpp::R_386_TLS_LE_32:
1015 bool output_is_shared = parameters->options().shared();
1016 const tls::Tls_optimization optimized_type
1017 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1018 switch (r_type)
1020 case elfcpp::R_386_TLS_GD: // Global-dynamic
1021 if (optimized_type == tls::TLSOPT_NONE)
1023 // Create a pair of GOT entries for the module index and
1024 // dtv-relative offset.
1025 Output_data_got<32, false>* got
1026 = target->got_section(symtab, layout);
1027 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1028 unsigned int shndx = lsym.get_st_shndx();
1029 bool is_ordinary;
1030 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1031 if (!is_ordinary)
1032 object->error(_("local symbol %u has bad shndx %u"),
1033 r_sym, shndx);
1034 else
1035 got->add_local_pair_with_rel(object, r_sym, shndx,
1036 GOT_TYPE_TLS_PAIR,
1037 target->rel_dyn_section(layout),
1038 elfcpp::R_386_TLS_DTPMOD32, 0);
1040 else if (optimized_type != tls::TLSOPT_TO_LE)
1041 unsupported_reloc_local(object, r_type);
1042 break;
1044 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1045 target->define_tls_base_symbol(symtab, layout);
1046 if (optimized_type == tls::TLSOPT_NONE)
1048 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1049 Output_data_got<32, false>* got
1050 = target->got_section(symtab, layout);
1051 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1052 unsigned int shndx = lsym.get_st_shndx();
1053 bool is_ordinary;
1054 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1055 if (!is_ordinary)
1056 object->error(_("local symbol %u has bad shndx %u"),
1057 r_sym, shndx);
1058 else
1059 got->add_local_pair_with_rel(object, r_sym, shndx,
1060 GOT_TYPE_TLS_DESC,
1061 target->rel_dyn_section(layout),
1062 elfcpp::R_386_TLS_DESC, 0);
1064 else if (optimized_type != tls::TLSOPT_TO_LE)
1065 unsupported_reloc_local(object, r_type);
1066 break;
1068 case elfcpp::R_386_TLS_DESC_CALL:
1069 break;
1071 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1072 if (optimized_type == tls::TLSOPT_NONE)
1074 // Create a GOT entry for the module index.
1075 target->got_mod_index_entry(symtab, layout, object);
1077 else if (optimized_type != tls::TLSOPT_TO_LE)
1078 unsupported_reloc_local(object, r_type);
1079 break;
1081 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1082 break;
1084 case elfcpp::R_386_TLS_IE: // Initial-exec
1085 case elfcpp::R_386_TLS_IE_32:
1086 case elfcpp::R_386_TLS_GOTIE:
1087 layout->set_has_static_tls();
1088 if (optimized_type == tls::TLSOPT_NONE)
1090 // For the R_386_TLS_IE relocation, we need to create a
1091 // dynamic relocation when building a shared library.
1092 if (r_type == elfcpp::R_386_TLS_IE
1093 && parameters->options().shared())
1095 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1096 unsigned int r_sym
1097 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1098 rel_dyn->add_local_relative(object, r_sym,
1099 elfcpp::R_386_RELATIVE,
1100 output_section, data_shndx,
1101 reloc.get_r_offset());
1103 // Create a GOT entry for the tp-relative offset.
1104 Output_data_got<32, false>* got
1105 = target->got_section(symtab, layout);
1106 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1107 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1108 ? elfcpp::R_386_TLS_TPOFF32
1109 : elfcpp::R_386_TLS_TPOFF);
1110 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1111 ? GOT_TYPE_TLS_OFFSET
1112 : GOT_TYPE_TLS_NOFFSET);
1113 got->add_local_with_rel(object, r_sym, got_type,
1114 target->rel_dyn_section(layout),
1115 dyn_r_type);
1117 else if (optimized_type != tls::TLSOPT_TO_LE)
1118 unsupported_reloc_local(object, r_type);
1119 break;
1121 case elfcpp::R_386_TLS_LE: // Local-exec
1122 case elfcpp::R_386_TLS_LE_32:
1123 layout->set_has_static_tls();
1124 if (output_is_shared)
1126 // We need to create a dynamic relocation.
1127 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1128 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1129 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1130 ? elfcpp::R_386_TLS_TPOFF32
1131 : elfcpp::R_386_TLS_TPOFF);
1132 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1133 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1134 data_shndx, reloc.get_r_offset());
1136 break;
1138 default:
1139 gold_unreachable();
1142 break;
1144 case elfcpp::R_386_32PLT:
1145 case elfcpp::R_386_TLS_GD_32:
1146 case elfcpp::R_386_TLS_GD_PUSH:
1147 case elfcpp::R_386_TLS_GD_CALL:
1148 case elfcpp::R_386_TLS_GD_POP:
1149 case elfcpp::R_386_TLS_LDM_32:
1150 case elfcpp::R_386_TLS_LDM_PUSH:
1151 case elfcpp::R_386_TLS_LDM_CALL:
1152 case elfcpp::R_386_TLS_LDM_POP:
1153 case elfcpp::R_386_USED_BY_INTEL_200:
1154 default:
1155 unsupported_reloc_local(object, r_type);
1156 break;
1160 // Report an unsupported relocation against a global symbol.
1162 void
1163 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1164 unsigned int r_type,
1165 Symbol* gsym)
1167 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1168 object->name().c_str(), r_type, gsym->demangled_name().c_str());
1171 // Scan a relocation for a global symbol.
1173 inline void
1174 Target_i386::Scan::global(Symbol_table* symtab,
1175 Layout* layout,
1176 Target_i386* target,
1177 Sized_relobj<32, false>* object,
1178 unsigned int data_shndx,
1179 Output_section* output_section,
1180 const elfcpp::Rel<32, false>& reloc,
1181 unsigned int r_type,
1182 Symbol* gsym)
1184 switch (r_type)
1186 case elfcpp::R_386_NONE:
1187 case elfcpp::R_386_GNU_VTINHERIT:
1188 case elfcpp::R_386_GNU_VTENTRY:
1189 break;
1191 case elfcpp::R_386_32:
1192 case elfcpp::R_386_16:
1193 case elfcpp::R_386_8:
1195 // Make a PLT entry if necessary.
1196 if (gsym->needs_plt_entry())
1198 target->make_plt_entry(symtab, layout, gsym);
1199 // Since this is not a PC-relative relocation, we may be
1200 // taking the address of a function. In that case we need to
1201 // set the entry in the dynamic symbol table to the address of
1202 // the PLT entry.
1203 if (gsym->is_from_dynobj() && !parameters->options().shared())
1204 gsym->set_needs_dynsym_value();
1206 // Make a dynamic relocation if necessary.
1207 if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1209 if (gsym->may_need_copy_reloc())
1211 target->copy_reloc(symtab, layout, object,
1212 data_shndx, output_section, gsym, reloc);
1214 else if (r_type == elfcpp::R_386_32
1215 && gsym->can_use_relative_reloc(false))
1217 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1218 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1219 output_section, object,
1220 data_shndx, reloc.get_r_offset());
1222 else
1224 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1225 rel_dyn->add_global(gsym, r_type, output_section, object,
1226 data_shndx, reloc.get_r_offset());
1230 break;
1232 case elfcpp::R_386_PC32:
1233 case elfcpp::R_386_PC16:
1234 case elfcpp::R_386_PC8:
1236 // Make a PLT entry if necessary.
1237 if (gsym->needs_plt_entry())
1239 // These relocations are used for function calls only in
1240 // non-PIC code. For a 32-bit relocation in a shared library,
1241 // we'll need a text relocation anyway, so we can skip the
1242 // PLT entry and let the dynamic linker bind the call directly
1243 // to the target. For smaller relocations, we should use a
1244 // PLT entry to ensure that the call can reach.
1245 if (!parameters->options().shared()
1246 || r_type != elfcpp::R_386_PC32)
1247 target->make_plt_entry(symtab, layout, gsym);
1249 // Make a dynamic relocation if necessary.
1250 int flags = Symbol::NON_PIC_REF;
1251 if (gsym->is_func())
1252 flags |= Symbol::FUNCTION_CALL;
1253 if (gsym->needs_dynamic_reloc(flags))
1255 if (gsym->may_need_copy_reloc())
1257 target->copy_reloc(symtab, layout, object,
1258 data_shndx, output_section, gsym, reloc);
1260 else
1262 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1263 rel_dyn->add_global(gsym, r_type, output_section, object,
1264 data_shndx, reloc.get_r_offset());
1268 break;
1270 case elfcpp::R_386_GOT32:
1272 // The symbol requires a GOT entry.
1273 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1274 if (gsym->final_value_is_known())
1275 got->add_global(gsym, GOT_TYPE_STANDARD);
1276 else
1278 // If this symbol is not fully resolved, we need to add a
1279 // GOT entry with a dynamic relocation.
1280 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1281 if (gsym->is_from_dynobj()
1282 || gsym->is_undefined()
1283 || gsym->is_preemptible())
1284 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
1285 rel_dyn, elfcpp::R_386_GLOB_DAT);
1286 else
1288 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1289 rel_dyn->add_global_relative(
1290 gsym, elfcpp::R_386_RELATIVE, got,
1291 gsym->got_offset(GOT_TYPE_STANDARD));
1295 break;
1297 case elfcpp::R_386_PLT32:
1298 // If the symbol is fully resolved, this is just a PC32 reloc.
1299 // Otherwise we need a PLT entry.
1300 if (gsym->final_value_is_known())
1301 break;
1302 // If building a shared library, we can also skip the PLT entry
1303 // if the symbol is defined in the output file and is protected
1304 // or hidden.
1305 if (gsym->is_defined()
1306 && !gsym->is_from_dynobj()
1307 && !gsym->is_preemptible())
1308 break;
1309 target->make_plt_entry(symtab, layout, gsym);
1310 break;
1312 case elfcpp::R_386_GOTOFF:
1313 case elfcpp::R_386_GOTPC:
1314 // We need a GOT section.
1315 target->got_section(symtab, layout);
1316 break;
1318 // These are relocations which should only be seen by the
1319 // dynamic linker, and should never be seen here.
1320 case elfcpp::R_386_COPY:
1321 case elfcpp::R_386_GLOB_DAT:
1322 case elfcpp::R_386_JUMP_SLOT:
1323 case elfcpp::R_386_RELATIVE:
1324 case elfcpp::R_386_TLS_TPOFF:
1325 case elfcpp::R_386_TLS_DTPMOD32:
1326 case elfcpp::R_386_TLS_DTPOFF32:
1327 case elfcpp::R_386_TLS_TPOFF32:
1328 case elfcpp::R_386_TLS_DESC:
1329 gold_error(_("%s: unexpected reloc %u in object file"),
1330 object->name().c_str(), r_type);
1331 break;
1333 // These are initial tls relocs, which are expected when
1334 // linking.
1335 case elfcpp::R_386_TLS_GD: // Global-dynamic
1336 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1337 case elfcpp::R_386_TLS_DESC_CALL:
1338 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1339 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1340 case elfcpp::R_386_TLS_IE: // Initial-exec
1341 case elfcpp::R_386_TLS_IE_32:
1342 case elfcpp::R_386_TLS_GOTIE:
1343 case elfcpp::R_386_TLS_LE: // Local-exec
1344 case elfcpp::R_386_TLS_LE_32:
1346 const bool is_final = gsym->final_value_is_known();
1347 const tls::Tls_optimization optimized_type
1348 = Target_i386::optimize_tls_reloc(is_final, r_type);
1349 switch (r_type)
1351 case elfcpp::R_386_TLS_GD: // Global-dynamic
1352 if (optimized_type == tls::TLSOPT_NONE)
1354 // Create a pair of GOT entries for the module index and
1355 // dtv-relative offset.
1356 Output_data_got<32, false>* got
1357 = target->got_section(symtab, layout);
1358 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
1359 target->rel_dyn_section(layout),
1360 elfcpp::R_386_TLS_DTPMOD32,
1361 elfcpp::R_386_TLS_DTPOFF32);
1363 else if (optimized_type == tls::TLSOPT_TO_IE)
1365 // Create a GOT entry for the tp-relative offset.
1366 Output_data_got<32, false>* got
1367 = target->got_section(symtab, layout);
1368 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1369 target->rel_dyn_section(layout),
1370 elfcpp::R_386_TLS_TPOFF);
1372 else if (optimized_type != tls::TLSOPT_TO_LE)
1373 unsupported_reloc_global(object, r_type, gsym);
1374 break;
1376 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1377 target->define_tls_base_symbol(symtab, layout);
1378 if (optimized_type == tls::TLSOPT_NONE)
1380 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1381 Output_data_got<32, false>* got
1382 = target->got_section(symtab, layout);
1383 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC,
1384 target->rel_dyn_section(layout),
1385 elfcpp::R_386_TLS_DESC, 0);
1387 else if (optimized_type == tls::TLSOPT_TO_IE)
1389 // Create a GOT entry for the tp-relative offset.
1390 Output_data_got<32, false>* got
1391 = target->got_section(symtab, layout);
1392 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1393 target->rel_dyn_section(layout),
1394 elfcpp::R_386_TLS_TPOFF);
1396 else if (optimized_type != tls::TLSOPT_TO_LE)
1397 unsupported_reloc_global(object, r_type, gsym);
1398 break;
1400 case elfcpp::R_386_TLS_DESC_CALL:
1401 break;
1403 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1404 if (optimized_type == tls::TLSOPT_NONE)
1406 // Create a GOT entry for the module index.
1407 target->got_mod_index_entry(symtab, layout, object);
1409 else if (optimized_type != tls::TLSOPT_TO_LE)
1410 unsupported_reloc_global(object, r_type, gsym);
1411 break;
1413 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1414 break;
1416 case elfcpp::R_386_TLS_IE: // Initial-exec
1417 case elfcpp::R_386_TLS_IE_32:
1418 case elfcpp::R_386_TLS_GOTIE:
1419 layout->set_has_static_tls();
1420 if (optimized_type == tls::TLSOPT_NONE)
1422 // For the R_386_TLS_IE relocation, we need to create a
1423 // dynamic relocation when building a shared library.
1424 if (r_type == elfcpp::R_386_TLS_IE
1425 && parameters->options().shared())
1427 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1428 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1429 output_section, object,
1430 data_shndx,
1431 reloc.get_r_offset());
1433 // Create a GOT entry for the tp-relative offset.
1434 Output_data_got<32, false>* got
1435 = target->got_section(symtab, layout);
1436 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1437 ? elfcpp::R_386_TLS_TPOFF32
1438 : elfcpp::R_386_TLS_TPOFF);
1439 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1440 ? GOT_TYPE_TLS_OFFSET
1441 : GOT_TYPE_TLS_NOFFSET);
1442 got->add_global_with_rel(gsym, got_type,
1443 target->rel_dyn_section(layout),
1444 dyn_r_type);
1446 else if (optimized_type != tls::TLSOPT_TO_LE)
1447 unsupported_reloc_global(object, r_type, gsym);
1448 break;
1450 case elfcpp::R_386_TLS_LE: // Local-exec
1451 case elfcpp::R_386_TLS_LE_32:
1452 layout->set_has_static_tls();
1453 if (parameters->options().shared())
1455 // We need to create a dynamic relocation.
1456 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1457 ? elfcpp::R_386_TLS_TPOFF32
1458 : elfcpp::R_386_TLS_TPOFF);
1459 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1460 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1461 data_shndx, reloc.get_r_offset());
1463 break;
1465 default:
1466 gold_unreachable();
1469 break;
1471 case elfcpp::R_386_32PLT:
1472 case elfcpp::R_386_TLS_GD_32:
1473 case elfcpp::R_386_TLS_GD_PUSH:
1474 case elfcpp::R_386_TLS_GD_CALL:
1475 case elfcpp::R_386_TLS_GD_POP:
1476 case elfcpp::R_386_TLS_LDM_32:
1477 case elfcpp::R_386_TLS_LDM_PUSH:
1478 case elfcpp::R_386_TLS_LDM_CALL:
1479 case elfcpp::R_386_TLS_LDM_POP:
1480 case elfcpp::R_386_USED_BY_INTEL_200:
1481 default:
1482 unsupported_reloc_global(object, r_type, gsym);
1483 break;
1487 // Process relocations for gc.
1489 void
1490 Target_i386::gc_process_relocs(Symbol_table* symtab,
1491 Layout* layout,
1492 Sized_relobj<32, false>* object,
1493 unsigned int data_shndx,
1494 unsigned int,
1495 const unsigned char* prelocs,
1496 size_t reloc_count,
1497 Output_section* output_section,
1498 bool needs_special_offset_handling,
1499 size_t local_symbol_count,
1500 const unsigned char* plocal_symbols)
1502 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1503 Target_i386::Scan>(
1504 symtab,
1505 layout,
1506 this,
1507 object,
1508 data_shndx,
1509 prelocs,
1510 reloc_count,
1511 output_section,
1512 needs_special_offset_handling,
1513 local_symbol_count,
1514 plocal_symbols);
1517 // Scan relocations for a section.
1519 void
1520 Target_i386::scan_relocs(Symbol_table* symtab,
1521 Layout* layout,
1522 Sized_relobj<32, false>* object,
1523 unsigned int data_shndx,
1524 unsigned int sh_type,
1525 const unsigned char* prelocs,
1526 size_t reloc_count,
1527 Output_section* output_section,
1528 bool needs_special_offset_handling,
1529 size_t local_symbol_count,
1530 const unsigned char* plocal_symbols)
1532 if (sh_type == elfcpp::SHT_RELA)
1534 gold_error(_("%s: unsupported RELA reloc section"),
1535 object->name().c_str());
1536 return;
1539 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1540 Target_i386::Scan>(
1541 symtab,
1542 layout,
1543 this,
1544 object,
1545 data_shndx,
1546 prelocs,
1547 reloc_count,
1548 output_section,
1549 needs_special_offset_handling,
1550 local_symbol_count,
1551 plocal_symbols);
1554 // Finalize the sections.
1556 void
1557 Target_i386::do_finalize_sections(
1558 Layout* layout,
1559 const Input_objects*,
1560 Symbol_table*)
1562 // Fill in some more dynamic tags.
1563 Output_data_dynamic* const odyn = layout->dynamic_data();
1564 if (odyn != NULL)
1566 if (this->got_plt_ != NULL
1567 && this->got_plt_->output_section() != NULL)
1568 odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1570 if (this->plt_ != NULL
1571 && this->plt_->output_section() != NULL)
1573 const Output_data* od = this->plt_->rel_plt();
1574 odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1575 odyn->add_section_address(elfcpp::DT_JMPREL, od);
1576 odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1579 if (this->rel_dyn_ != NULL
1580 && this->rel_dyn_->output_section() != NULL)
1582 const Output_data* od = this->rel_dyn_;
1583 odyn->add_section_address(elfcpp::DT_REL, od);
1584 odyn->add_section_size(elfcpp::DT_RELSZ, od);
1585 odyn->add_constant(elfcpp::DT_RELENT,
1586 elfcpp::Elf_sizes<32>::rel_size);
1589 if (!parameters->options().shared())
1591 // The value of the DT_DEBUG tag is filled in by the dynamic
1592 // linker at run time, and used by the debugger.
1593 odyn->add_constant(elfcpp::DT_DEBUG, 0);
1597 // Emit any relocs we saved in an attempt to avoid generating COPY
1598 // relocs.
1599 if (this->copy_relocs_.any_saved_relocs())
1600 this->copy_relocs_.emit(this->rel_dyn_section(layout));
1603 // Return whether a direct absolute static relocation needs to be applied.
1604 // In cases where Scan::local() or Scan::global() has created
1605 // a dynamic relocation other than R_386_RELATIVE, the addend
1606 // of the relocation is carried in the data, and we must not
1607 // apply the static relocation.
1609 inline bool
1610 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1611 int ref_flags,
1612 bool is_32bit,
1613 Output_section* output_section)
1615 // If the output section is not allocated, then we didn't call
1616 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1617 // the reloc here.
1618 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
1619 return true;
1621 // For local symbols, we will have created a non-RELATIVE dynamic
1622 // relocation only if (a) the output is position independent,
1623 // (b) the relocation is absolute (not pc- or segment-relative), and
1624 // (c) the relocation is not 32 bits wide.
1625 if (gsym == NULL)
1626 return !(parameters->options().output_is_position_independent()
1627 && (ref_flags & Symbol::ABSOLUTE_REF)
1628 && !is_32bit);
1630 // For global symbols, we use the same helper routines used in the
1631 // scan pass. If we did not create a dynamic relocation, or if we
1632 // created a RELATIVE dynamic relocation, we should apply the static
1633 // relocation.
1634 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
1635 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
1636 && gsym->can_use_relative_reloc(ref_flags
1637 & Symbol::FUNCTION_CALL);
1638 return !has_dyn || is_rel;
1641 // Perform a relocation.
1643 inline bool
1644 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1645 Target_i386* target,
1646 Output_section *output_section,
1647 size_t relnum,
1648 const elfcpp::Rel<32, false>& rel,
1649 unsigned int r_type,
1650 const Sized_symbol<32>* gsym,
1651 const Symbol_value<32>* psymval,
1652 unsigned char* view,
1653 elfcpp::Elf_types<32>::Elf_Addr address,
1654 section_size_type view_size)
1656 if (this->skip_call_tls_get_addr_)
1658 if ((r_type != elfcpp::R_386_PLT32
1659 && r_type != elfcpp::R_386_PC32)
1660 || gsym == NULL
1661 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1662 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1663 _("missing expected TLS relocation"));
1664 else
1666 this->skip_call_tls_get_addr_ = false;
1667 return false;
1671 // Pick the value to use for symbols defined in shared objects.
1672 Symbol_value<32> symval;
1673 if (gsym != NULL
1674 && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
1675 || r_type == elfcpp::R_386_PC16
1676 || r_type == elfcpp::R_386_PC32))
1678 symval.set_output_value(target->plt_section()->address()
1679 + gsym->plt_offset());
1680 psymval = &symval;
1683 const Sized_relobj<32, false>* object = relinfo->object;
1685 // Get the GOT offset if needed.
1686 // The GOT pointer points to the end of the GOT section.
1687 // We need to subtract the size of the GOT section to get
1688 // the actual offset to use in the relocation.
1689 bool have_got_offset = false;
1690 unsigned int got_offset = 0;
1691 switch (r_type)
1693 case elfcpp::R_386_GOT32:
1694 if (gsym != NULL)
1696 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1697 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
1698 - target->got_size());
1700 else
1702 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1703 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1704 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1705 - target->got_size());
1707 have_got_offset = true;
1708 break;
1710 default:
1711 break;
1714 switch (r_type)
1716 case elfcpp::R_386_NONE:
1717 case elfcpp::R_386_GNU_VTINHERIT:
1718 case elfcpp::R_386_GNU_VTENTRY:
1719 break;
1721 case elfcpp::R_386_32:
1722 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
1723 output_section))
1724 Relocate_functions<32, false>::rel32(view, object, psymval);
1725 break;
1727 case elfcpp::R_386_PC32:
1729 int ref_flags = Symbol::NON_PIC_REF;
1730 if (gsym != NULL && gsym->is_func())
1731 ref_flags |= Symbol::FUNCTION_CALL;
1732 if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
1733 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1735 break;
1737 case elfcpp::R_386_16:
1738 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1739 output_section))
1740 Relocate_functions<32, false>::rel16(view, object, psymval);
1741 break;
1743 case elfcpp::R_386_PC16:
1745 int ref_flags = Symbol::NON_PIC_REF;
1746 if (gsym != NULL && gsym->is_func())
1747 ref_flags |= Symbol::FUNCTION_CALL;
1748 if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
1749 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1751 break;
1753 case elfcpp::R_386_8:
1754 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1755 output_section))
1756 Relocate_functions<32, false>::rel8(view, object, psymval);
1757 break;
1759 case elfcpp::R_386_PC8:
1761 int ref_flags = Symbol::NON_PIC_REF;
1762 if (gsym != NULL && gsym->is_func())
1763 ref_flags |= Symbol::FUNCTION_CALL;
1764 if (should_apply_static_reloc(gsym, ref_flags, false,
1765 output_section))
1766 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1768 break;
1770 case elfcpp::R_386_PLT32:
1771 gold_assert(gsym == NULL
1772 || gsym->has_plt_offset()
1773 || gsym->final_value_is_known()
1774 || (gsym->is_defined()
1775 && !gsym->is_from_dynobj()
1776 && !gsym->is_preemptible()));
1777 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1778 break;
1780 case elfcpp::R_386_GOT32:
1781 gold_assert(have_got_offset);
1782 Relocate_functions<32, false>::rel32(view, got_offset);
1783 break;
1785 case elfcpp::R_386_GOTOFF:
1787 elfcpp::Elf_types<32>::Elf_Addr value;
1788 value = (psymval->value(object, 0)
1789 - target->got_plt_section()->address());
1790 Relocate_functions<32, false>::rel32(view, value);
1792 break;
1794 case elfcpp::R_386_GOTPC:
1796 elfcpp::Elf_types<32>::Elf_Addr value;
1797 value = target->got_plt_section()->address();
1798 Relocate_functions<32, false>::pcrel32(view, value, address);
1800 break;
1802 case elfcpp::R_386_COPY:
1803 case elfcpp::R_386_GLOB_DAT:
1804 case elfcpp::R_386_JUMP_SLOT:
1805 case elfcpp::R_386_RELATIVE:
1806 // These are outstanding tls relocs, which are unexpected when
1807 // linking.
1808 case elfcpp::R_386_TLS_TPOFF:
1809 case elfcpp::R_386_TLS_DTPMOD32:
1810 case elfcpp::R_386_TLS_DTPOFF32:
1811 case elfcpp::R_386_TLS_TPOFF32:
1812 case elfcpp::R_386_TLS_DESC:
1813 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1814 _("unexpected reloc %u in object file"),
1815 r_type);
1816 break;
1818 // These are initial tls relocs, which are expected when
1819 // linking.
1820 case elfcpp::R_386_TLS_GD: // Global-dynamic
1821 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1822 case elfcpp::R_386_TLS_DESC_CALL:
1823 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1824 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1825 case elfcpp::R_386_TLS_IE: // Initial-exec
1826 case elfcpp::R_386_TLS_IE_32:
1827 case elfcpp::R_386_TLS_GOTIE:
1828 case elfcpp::R_386_TLS_LE: // Local-exec
1829 case elfcpp::R_386_TLS_LE_32:
1830 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1831 view, address, view_size);
1832 break;
1834 case elfcpp::R_386_32PLT:
1835 case elfcpp::R_386_TLS_GD_32:
1836 case elfcpp::R_386_TLS_GD_PUSH:
1837 case elfcpp::R_386_TLS_GD_CALL:
1838 case elfcpp::R_386_TLS_GD_POP:
1839 case elfcpp::R_386_TLS_LDM_32:
1840 case elfcpp::R_386_TLS_LDM_PUSH:
1841 case elfcpp::R_386_TLS_LDM_CALL:
1842 case elfcpp::R_386_TLS_LDM_POP:
1843 case elfcpp::R_386_USED_BY_INTEL_200:
1844 default:
1845 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1846 _("unsupported reloc %u"),
1847 r_type);
1848 break;
1851 return true;
1854 // Perform a TLS relocation.
1856 inline void
1857 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1858 Target_i386* target,
1859 size_t relnum,
1860 const elfcpp::Rel<32, false>& rel,
1861 unsigned int r_type,
1862 const Sized_symbol<32>* gsym,
1863 const Symbol_value<32>* psymval,
1864 unsigned char* view,
1865 elfcpp::Elf_types<32>::Elf_Addr,
1866 section_size_type view_size)
1868 Output_segment* tls_segment = relinfo->layout->tls_segment();
1870 const Sized_relobj<32, false>* object = relinfo->object;
1872 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1874 const bool is_final =
1875 (gsym == NULL
1876 ? !parameters->options().output_is_position_independent()
1877 : gsym->final_value_is_known());
1878 const tls::Tls_optimization optimized_type
1879 = Target_i386::optimize_tls_reloc(is_final, r_type);
1880 switch (r_type)
1882 case elfcpp::R_386_TLS_GD: // Global-dynamic
1883 if (optimized_type == tls::TLSOPT_TO_LE)
1885 gold_assert(tls_segment != NULL);
1886 this->tls_gd_to_le(relinfo, relnum, tls_segment,
1887 rel, r_type, value, view,
1888 view_size);
1889 break;
1891 else
1893 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1894 ? GOT_TYPE_TLS_NOFFSET
1895 : GOT_TYPE_TLS_PAIR);
1896 unsigned int got_offset;
1897 if (gsym != NULL)
1899 gold_assert(gsym->has_got_offset(got_type));
1900 got_offset = gsym->got_offset(got_type) - target->got_size();
1902 else
1904 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1905 gold_assert(object->local_has_got_offset(r_sym, got_type));
1906 got_offset = (object->local_got_offset(r_sym, got_type)
1907 - target->got_size());
1909 if (optimized_type == tls::TLSOPT_TO_IE)
1911 gold_assert(tls_segment != NULL);
1912 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1913 got_offset, view, view_size);
1914 break;
1916 else if (optimized_type == tls::TLSOPT_NONE)
1918 // Relocate the field with the offset of the pair of GOT
1919 // entries.
1920 Relocate_functions<32, false>::rel32(view, got_offset);
1921 break;
1924 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1925 _("unsupported reloc %u"),
1926 r_type);
1927 break;
1929 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1930 case elfcpp::R_386_TLS_DESC_CALL:
1931 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1932 if (optimized_type == tls::TLSOPT_TO_LE)
1934 gold_assert(tls_segment != NULL);
1935 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
1936 rel, r_type, value, view,
1937 view_size);
1938 break;
1940 else
1942 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1943 ? GOT_TYPE_TLS_NOFFSET
1944 : GOT_TYPE_TLS_DESC);
1945 unsigned int got_offset;
1946 if (gsym != NULL)
1948 gold_assert(gsym->has_got_offset(got_type));
1949 got_offset = gsym->got_offset(got_type) - target->got_size();
1951 else
1953 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1954 gold_assert(object->local_has_got_offset(r_sym, got_type));
1955 got_offset = (object->local_got_offset(r_sym, got_type)
1956 - target->got_size());
1958 if (optimized_type == tls::TLSOPT_TO_IE)
1960 gold_assert(tls_segment != NULL);
1961 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1962 got_offset, view, view_size);
1963 break;
1965 else if (optimized_type == tls::TLSOPT_NONE)
1967 if (r_type == elfcpp::R_386_TLS_GOTDESC)
1969 // Relocate the field with the offset of the pair of GOT
1970 // entries.
1971 Relocate_functions<32, false>::rel32(view, got_offset);
1973 break;
1976 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1977 _("unsupported reloc %u"),
1978 r_type);
1979 break;
1981 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1982 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1984 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1985 _("both SUN and GNU model "
1986 "TLS relocations"));
1987 break;
1989 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1990 if (optimized_type == tls::TLSOPT_TO_LE)
1992 gold_assert(tls_segment != NULL);
1993 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1994 value, view, view_size);
1995 break;
1997 else if (optimized_type == tls::TLSOPT_NONE)
1999 // Relocate the field with the offset of the GOT entry for
2000 // the module index.
2001 unsigned int got_offset;
2002 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2003 - target->got_size());
2004 Relocate_functions<32, false>::rel32(view, got_offset);
2005 break;
2007 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2008 _("unsupported reloc %u"),
2009 r_type);
2010 break;
2012 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2013 if (optimized_type == tls::TLSOPT_TO_LE)
2015 // This reloc can appear in debugging sections, in which
2016 // case we must not convert to local-exec. We decide what
2017 // to do based on whether the section is marked as
2018 // containing executable code. That is what the GNU linker
2019 // does as well.
2020 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
2021 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
2023 gold_assert(tls_segment != NULL);
2024 value -= tls_segment->memsz();
2027 Relocate_functions<32, false>::rel32(view, value);
2028 break;
2030 case elfcpp::R_386_TLS_IE: // Initial-exec
2031 case elfcpp::R_386_TLS_GOTIE:
2032 case elfcpp::R_386_TLS_IE_32:
2033 if (optimized_type == tls::TLSOPT_TO_LE)
2035 gold_assert(tls_segment != NULL);
2036 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2037 rel, r_type, value, view,
2038 view_size);
2039 break;
2041 else if (optimized_type == tls::TLSOPT_NONE)
2043 // Relocate the field with the offset of the GOT entry for
2044 // the tp-relative offset of the symbol.
2045 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2046 ? GOT_TYPE_TLS_OFFSET
2047 : GOT_TYPE_TLS_NOFFSET);
2048 unsigned int got_offset;
2049 if (gsym != NULL)
2051 gold_assert(gsym->has_got_offset(got_type));
2052 got_offset = gsym->got_offset(got_type);
2054 else
2056 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2057 gold_assert(object->local_has_got_offset(r_sym, got_type));
2058 got_offset = object->local_got_offset(r_sym, got_type);
2060 // For the R_386_TLS_IE relocation, we need to apply the
2061 // absolute address of the GOT entry.
2062 if (r_type == elfcpp::R_386_TLS_IE)
2063 got_offset += target->got_plt_section()->address();
2064 // All GOT offsets are relative to the end of the GOT.
2065 got_offset -= target->got_size();
2066 Relocate_functions<32, false>::rel32(view, got_offset);
2067 break;
2069 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2070 _("unsupported reloc %u"),
2071 r_type);
2072 break;
2074 case elfcpp::R_386_TLS_LE: // Local-exec
2075 // If we're creating a shared library, a dynamic relocation will
2076 // have been created for this location, so do not apply it now.
2077 if (!parameters->options().shared())
2079 gold_assert(tls_segment != NULL);
2080 value -= tls_segment->memsz();
2081 Relocate_functions<32, false>::rel32(view, value);
2083 break;
2085 case elfcpp::R_386_TLS_LE_32:
2086 // If we're creating a shared library, a dynamic relocation will
2087 // have been created for this location, so do not apply it now.
2088 if (!parameters->options().shared())
2090 gold_assert(tls_segment != NULL);
2091 value = tls_segment->memsz() - value;
2092 Relocate_functions<32, false>::rel32(view, value);
2094 break;
2098 // Do a relocation in which we convert a TLS General-Dynamic to a
2099 // Local-Exec.
2101 inline void
2102 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
2103 size_t relnum,
2104 Output_segment* tls_segment,
2105 const elfcpp::Rel<32, false>& rel,
2106 unsigned int,
2107 elfcpp::Elf_types<32>::Elf_Addr value,
2108 unsigned char* view,
2109 section_size_type view_size)
2111 // leal foo(,%reg,1),%eax; call ___tls_get_addr
2112 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2113 // leal foo(%reg),%eax; call ___tls_get_addr
2114 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2116 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2117 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2119 unsigned char op1 = view[-1];
2120 unsigned char op2 = view[-2];
2122 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2123 op2 == 0x8d || op2 == 0x04);
2124 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2126 int roff = 5;
2128 if (op2 == 0x04)
2130 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2131 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2132 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2133 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2134 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2136 else
2138 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2139 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2140 if (rel.get_r_offset() + 9 < view_size
2141 && view[9] == 0x90)
2143 // There is a trailing nop. Use the size byte subl.
2144 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2145 roff = 6;
2147 else
2149 // Use the five byte subl.
2150 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2154 value = tls_segment->memsz() - value;
2155 Relocate_functions<32, false>::rel32(view + roff, value);
2157 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2158 // We can skip it.
2159 this->skip_call_tls_get_addr_ = true;
2162 // Do a relocation in which we convert a TLS General-Dynamic to an
2163 // Initial-Exec.
2165 inline void
2166 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
2167 size_t relnum,
2168 Output_segment*,
2169 const elfcpp::Rel<32, false>& rel,
2170 unsigned int,
2171 elfcpp::Elf_types<32>::Elf_Addr value,
2172 unsigned char* view,
2173 section_size_type view_size)
2175 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
2176 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
2178 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2179 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2181 unsigned char op1 = view[-1];
2182 unsigned char op2 = view[-2];
2184 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2185 op2 == 0x8d || op2 == 0x04);
2186 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2188 int roff = 5;
2190 // FIXME: For now, support only the first (SIB) form.
2191 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
2193 if (op2 == 0x04)
2195 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2196 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2197 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2198 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2199 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
2201 else
2203 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2204 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2205 if (rel.get_r_offset() + 9 < view_size
2206 && view[9] == 0x90)
2208 // FIXME: This is not the right instruction sequence.
2209 // There is a trailing nop. Use the size byte subl.
2210 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2211 roff = 6;
2213 else
2215 // FIXME: This is not the right instruction sequence.
2216 // Use the five byte subl.
2217 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2221 Relocate_functions<32, false>::rel32(view + roff, value);
2223 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2224 // We can skip it.
2225 this->skip_call_tls_get_addr_ = true;
2228 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2229 // General-Dynamic to a Local-Exec.
2231 inline void
2232 Target_i386::Relocate::tls_desc_gd_to_le(
2233 const Relocate_info<32, false>* relinfo,
2234 size_t relnum,
2235 Output_segment* tls_segment,
2236 const elfcpp::Rel<32, false>& rel,
2237 unsigned int r_type,
2238 elfcpp::Elf_types<32>::Elf_Addr value,
2239 unsigned char* view,
2240 section_size_type view_size)
2242 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2244 // leal foo@TLSDESC(%ebx), %eax
2245 // ==> leal foo@NTPOFF, %eax
2246 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2247 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2248 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2249 view[-2] == 0x8d && view[-1] == 0x83);
2250 view[-1] = 0x05;
2251 value -= tls_segment->memsz();
2252 Relocate_functions<32, false>::rel32(view, value);
2254 else
2256 // call *foo@TLSCALL(%eax)
2257 // ==> nop; nop
2258 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2259 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2260 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2261 view[0] == 0xff && view[1] == 0x10);
2262 view[0] = 0x66;
2263 view[1] = 0x90;
2267 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2268 // General-Dynamic to an Initial-Exec.
2270 inline void
2271 Target_i386::Relocate::tls_desc_gd_to_ie(
2272 const Relocate_info<32, false>* relinfo,
2273 size_t relnum,
2274 Output_segment*,
2275 const elfcpp::Rel<32, false>& rel,
2276 unsigned int r_type,
2277 elfcpp::Elf_types<32>::Elf_Addr value,
2278 unsigned char* view,
2279 section_size_type view_size)
2281 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2283 // leal foo@TLSDESC(%ebx), %eax
2284 // ==> movl foo@GOTNTPOFF(%ebx), %eax
2285 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2286 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2287 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2288 view[-2] == 0x8d && view[-1] == 0x83);
2289 view[-2] = 0x8b;
2290 Relocate_functions<32, false>::rel32(view, value);
2292 else
2294 // call *foo@TLSCALL(%eax)
2295 // ==> nop; nop
2296 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2297 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2298 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2299 view[0] == 0xff && view[1] == 0x10);
2300 view[0] = 0x66;
2301 view[1] = 0x90;
2305 // Do a relocation in which we convert a TLS Local-Dynamic to a
2306 // Local-Exec.
2308 inline void
2309 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
2310 size_t relnum,
2311 Output_segment*,
2312 const elfcpp::Rel<32, false>& rel,
2313 unsigned int,
2314 elfcpp::Elf_types<32>::Elf_Addr,
2315 unsigned char* view,
2316 section_size_type view_size)
2318 // leal foo(%reg), %eax; call ___tls_get_addr
2319 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
2321 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2322 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2324 // FIXME: Does this test really always pass?
2325 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2326 view[-2] == 0x8d && view[-1] == 0x83);
2328 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2330 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
2332 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2333 // We can skip it.
2334 this->skip_call_tls_get_addr_ = true;
2337 // Do a relocation in which we convert a TLS Initial-Exec to a
2338 // Local-Exec.
2340 inline void
2341 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2342 size_t relnum,
2343 Output_segment* tls_segment,
2344 const elfcpp::Rel<32, false>& rel,
2345 unsigned int r_type,
2346 elfcpp::Elf_types<32>::Elf_Addr value,
2347 unsigned char* view,
2348 section_size_type view_size)
2350 // We have to actually change the instructions, which means that we
2351 // need to examine the opcodes to figure out which instruction we
2352 // are looking at.
2353 if (r_type == elfcpp::R_386_TLS_IE)
2355 // movl %gs:XX,%eax ==> movl $YY,%eax
2356 // movl %gs:XX,%reg ==> movl $YY,%reg
2357 // addl %gs:XX,%reg ==> addl $YY,%reg
2358 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2359 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2361 unsigned char op1 = view[-1];
2362 if (op1 == 0xa1)
2364 // movl XX,%eax ==> movl $YY,%eax
2365 view[-1] = 0xb8;
2367 else
2369 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2371 unsigned char op2 = view[-2];
2372 if (op2 == 0x8b)
2374 // movl XX,%reg ==> movl $YY,%reg
2375 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2376 (op1 & 0xc7) == 0x05);
2377 view[-2] = 0xc7;
2378 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2380 else if (op2 == 0x03)
2382 // addl XX,%reg ==> addl $YY,%reg
2383 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2384 (op1 & 0xc7) == 0x05);
2385 view[-2] = 0x81;
2386 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2388 else
2389 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2392 else
2394 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2395 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2396 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2397 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2398 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2400 unsigned char op1 = view[-1];
2401 unsigned char op2 = view[-2];
2402 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2403 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2404 if (op2 == 0x8b)
2406 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2407 view[-2] = 0xc7;
2408 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2410 else if (op2 == 0x2b)
2412 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2413 view[-2] = 0x81;
2414 view[-1] = 0xe8 | ((op1 >> 3) & 7);
2416 else if (op2 == 0x03)
2418 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2419 view[-2] = 0x81;
2420 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2422 else
2423 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2426 value = tls_segment->memsz() - value;
2427 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2428 value = - value;
2430 Relocate_functions<32, false>::rel32(view, value);
2433 // Relocate section data.
2435 void
2436 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2437 unsigned int sh_type,
2438 const unsigned char* prelocs,
2439 size_t reloc_count,
2440 Output_section* output_section,
2441 bool needs_special_offset_handling,
2442 unsigned char* view,
2443 elfcpp::Elf_types<32>::Elf_Addr address,
2444 section_size_type view_size,
2445 const Reloc_symbol_changes* reloc_symbol_changes)
2447 gold_assert(sh_type == elfcpp::SHT_REL);
2449 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2450 Target_i386::Relocate>(
2451 relinfo,
2452 this,
2453 prelocs,
2454 reloc_count,
2455 output_section,
2456 needs_special_offset_handling,
2457 view,
2458 address,
2459 view_size,
2460 reloc_symbol_changes);
2463 // Return the size of a relocation while scanning during a relocatable
2464 // link.
2466 unsigned int
2467 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
2468 unsigned int r_type,
2469 Relobj* object)
2471 switch (r_type)
2473 case elfcpp::R_386_NONE:
2474 case elfcpp::R_386_GNU_VTINHERIT:
2475 case elfcpp::R_386_GNU_VTENTRY:
2476 case elfcpp::R_386_TLS_GD: // Global-dynamic
2477 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2478 case elfcpp::R_386_TLS_DESC_CALL:
2479 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2480 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2481 case elfcpp::R_386_TLS_IE: // Initial-exec
2482 case elfcpp::R_386_TLS_IE_32:
2483 case elfcpp::R_386_TLS_GOTIE:
2484 case elfcpp::R_386_TLS_LE: // Local-exec
2485 case elfcpp::R_386_TLS_LE_32:
2486 return 0;
2488 case elfcpp::R_386_32:
2489 case elfcpp::R_386_PC32:
2490 case elfcpp::R_386_GOT32:
2491 case elfcpp::R_386_PLT32:
2492 case elfcpp::R_386_GOTOFF:
2493 case elfcpp::R_386_GOTPC:
2494 return 4;
2496 case elfcpp::R_386_16:
2497 case elfcpp::R_386_PC16:
2498 return 2;
2500 case elfcpp::R_386_8:
2501 case elfcpp::R_386_PC8:
2502 return 1;
2504 // These are relocations which should only be seen by the
2505 // dynamic linker, and should never be seen here.
2506 case elfcpp::R_386_COPY:
2507 case elfcpp::R_386_GLOB_DAT:
2508 case elfcpp::R_386_JUMP_SLOT:
2509 case elfcpp::R_386_RELATIVE:
2510 case elfcpp::R_386_TLS_TPOFF:
2511 case elfcpp::R_386_TLS_DTPMOD32:
2512 case elfcpp::R_386_TLS_DTPOFF32:
2513 case elfcpp::R_386_TLS_TPOFF32:
2514 case elfcpp::R_386_TLS_DESC:
2515 object->error(_("unexpected reloc %u in object file"), r_type);
2516 return 0;
2518 case elfcpp::R_386_32PLT:
2519 case elfcpp::R_386_TLS_GD_32:
2520 case elfcpp::R_386_TLS_GD_PUSH:
2521 case elfcpp::R_386_TLS_GD_CALL:
2522 case elfcpp::R_386_TLS_GD_POP:
2523 case elfcpp::R_386_TLS_LDM_32:
2524 case elfcpp::R_386_TLS_LDM_PUSH:
2525 case elfcpp::R_386_TLS_LDM_CALL:
2526 case elfcpp::R_386_TLS_LDM_POP:
2527 case elfcpp::R_386_USED_BY_INTEL_200:
2528 default:
2529 object->error(_("unsupported reloc %u in object file"), r_type);
2530 return 0;
2534 // Scan the relocs during a relocatable link.
2536 void
2537 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
2538 Layout* layout,
2539 Sized_relobj<32, false>* object,
2540 unsigned int data_shndx,
2541 unsigned int sh_type,
2542 const unsigned char* prelocs,
2543 size_t reloc_count,
2544 Output_section* output_section,
2545 bool needs_special_offset_handling,
2546 size_t local_symbol_count,
2547 const unsigned char* plocal_symbols,
2548 Relocatable_relocs* rr)
2550 gold_assert(sh_type == elfcpp::SHT_REL);
2552 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
2553 Relocatable_size_for_reloc> Scan_relocatable_relocs;
2555 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
2556 Scan_relocatable_relocs>(
2557 symtab,
2558 layout,
2559 object,
2560 data_shndx,
2561 prelocs,
2562 reloc_count,
2563 output_section,
2564 needs_special_offset_handling,
2565 local_symbol_count,
2566 plocal_symbols,
2567 rr);
2570 // Relocate a section during a relocatable link.
2572 void
2573 Target_i386::relocate_for_relocatable(
2574 const Relocate_info<32, false>* relinfo,
2575 unsigned int sh_type,
2576 const unsigned char* prelocs,
2577 size_t reloc_count,
2578 Output_section* output_section,
2579 off_t offset_in_output_section,
2580 const Relocatable_relocs* rr,
2581 unsigned char* view,
2582 elfcpp::Elf_types<32>::Elf_Addr view_address,
2583 section_size_type view_size,
2584 unsigned char* reloc_view,
2585 section_size_type reloc_view_size)
2587 gold_assert(sh_type == elfcpp::SHT_REL);
2589 gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
2590 relinfo,
2591 prelocs,
2592 reloc_count,
2593 output_section,
2594 offset_in_output_section,
2596 view,
2597 view_address,
2598 view_size,
2599 reloc_view,
2600 reloc_view_size);
2603 // Return the value to use for a dynamic which requires special
2604 // treatment. This is how we support equality comparisons of function
2605 // pointers across shared library boundaries, as described in the
2606 // processor specific ABI supplement.
2608 uint64_t
2609 Target_i386::do_dynsym_value(const Symbol* gsym) const
2611 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2612 return this->plt_section()->address() + gsym->plt_offset();
2615 // Return a string used to fill a code section with nops to take up
2616 // the specified length.
2618 std::string
2619 Target_i386::do_code_fill(section_size_type length) const
2621 if (length >= 16)
2623 // Build a jmp instruction to skip over the bytes.
2624 unsigned char jmp[5];
2625 jmp[0] = 0xe9;
2626 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2627 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2628 + std::string(length - 5, '\0'));
2631 // Nop sequences of various lengths.
2632 const char nop1[1] = { 0x90 }; // nop
2633 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
2634 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
2635 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
2636 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
2637 0x00 }; // leal 0(%esi,1),%esi
2638 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2639 0x00, 0x00 };
2640 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2641 0x00, 0x00, 0x00 };
2642 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
2643 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2644 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
2645 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
2646 0x00 };
2647 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2648 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2649 0x00, 0x00 };
2650 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2651 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2652 0x00, 0x00, 0x00 };
2653 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2654 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2655 0x00, 0x00, 0x00, 0x00 };
2656 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2657 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2658 0x27, 0x00, 0x00, 0x00,
2659 0x00 };
2660 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2661 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2662 0xbc, 0x27, 0x00, 0x00,
2663 0x00, 0x00 };
2664 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2665 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2666 0x90, 0x90, 0x90, 0x90,
2667 0x90, 0x90, 0x90 };
2669 const char* nops[16] = {
2670 NULL,
2671 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2672 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2675 return std::string(nops[length], length);
2678 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2679 // compiled with -fstack-split. The function calls non-stack-split
2680 // code. We have to change the function so that it always ensures
2681 // that it has enough stack space to run some random function.
2683 void
2684 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
2685 section_offset_type fnoffset,
2686 section_size_type fnsize,
2687 unsigned char* view,
2688 section_size_type view_size,
2689 std::string* from,
2690 std::string* to) const
2692 // The function starts with a comparison of the stack pointer and a
2693 // field in the TCB. This is followed by a jump.
2695 // cmp %gs:NN,%esp
2696 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
2697 && fnsize > 7)
2699 // We will call __morestack if the carry flag is set after this
2700 // comparison. We turn the comparison into an stc instruction
2701 // and some nops.
2702 view[fnoffset] = '\xf9';
2703 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
2705 // lea NN(%esp),%ecx
2706 else if (this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
2707 && fnsize > 7)
2709 // This is loading an offset from the stack pointer for a
2710 // comparison. The offset is negative, so we decrease the
2711 // offset by the amount of space we need for the stack. This
2712 // means we will avoid calling __morestack if there happens to
2713 // be plenty of space on the stack already.
2714 unsigned char* pval = view + fnoffset + 3;
2715 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2716 val -= parameters->options().split_stack_adjust_size();
2717 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2719 else
2721 if (!object->has_no_split_stack())
2722 object->error(_("failed to match split-stack sequence at "
2723 "section %u offset %0zx"),
2724 shndx, static_cast<size_t>(fnoffset));
2725 return;
2728 // We have to change the function so that it calls
2729 // __morestack_non_split instead of __morestack. The former will
2730 // allocate additional stack space.
2731 *from = "__morestack";
2732 *to = "__morestack_non_split";
2735 // The selector for i386 object files.
2737 class Target_selector_i386 : public Target_selector_freebsd
2739 public:
2740 Target_selector_i386()
2741 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
2742 "elf32-i386", "elf32-i386-freebsd")
2745 Target*
2746 do_instantiate_target()
2747 { return new Target_i386(); }
2750 Target_selector_i386 target_selector_i386;
2752 } // End anonymous namespace.