1 // i386.cc -- i386 target support for gold.
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
28 #include "parameters.h"
36 #include "target-reloc.h"
37 #include "target-select.h"
45 class Output_data_plt_i386;
47 // The i386 target class.
48 // TLS info comes from
49 // http://people.redhat.com/drepper/tls.pdf
50 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
52 class Target_i386 : public Sized_target<32, false>
55 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
58 : Sized_target<32, false>(&i386_info),
59 got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
60 copy_relocs_(NULL), dynbss_(NULL)
63 // Scan the relocations to look for symbol adjustments.
65 scan_relocs(const General_options& options,
68 Sized_relobj<32, false>* object,
69 unsigned int data_shndx,
71 const unsigned char* prelocs,
73 size_t local_symbol_count,
74 const unsigned char* plocal_symbols,
75 Symbol** global_symbols);
77 // Finalize the sections.
79 do_finalize_sections(Layout*);
81 // Return the value to use for a dynamic which requires special
84 do_dynsym_value(const Symbol*) const;
86 // Relocate a section.
88 relocate_section(const Relocate_info<32, false>*,
90 const unsigned char* prelocs,
93 elfcpp::Elf_types<32>::Elf_Addr view_address,
96 // Return a string used to fill a code section with nops.
98 do_code_fill(off_t length);
101 // The class which scans relocations.
105 local(const General_options& options, Symbol_table* symtab,
106 Layout* layout, Target_i386* target,
107 Sized_relobj<32, false>* object,
108 unsigned int data_shndx,
109 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
110 const elfcpp::Sym<32, false>& lsym);
113 global(const General_options& options, Symbol_table* symtab,
114 Layout* layout, Target_i386* target,
115 Sized_relobj<32, false>* object,
116 unsigned int data_shndx,
117 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
121 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
124 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
128 // The class which implements relocation.
133 : skip_call_tls_get_addr_(false),
134 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
139 if (this->skip_call_tls_get_addr_)
141 // FIXME: This needs to specify the location somehow.
142 gold_error(_("missing expected TLS relocation"));
146 // Do a relocation. Return false if the caller should not issue
147 // any warnings about this relocation.
149 relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
150 const elfcpp::Rel<32, false>&,
151 unsigned int r_type, const Sized_symbol<32>*,
152 const Symbol_value<32>*,
153 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
157 // Do a TLS relocation.
159 relocate_tls(const Relocate_info<32, false>*, size_t relnum,
160 const elfcpp::Rel<32, false>&,
161 unsigned int r_type, const Sized_symbol<32>*,
162 const Symbol_value<32>*,
163 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
165 // Do a TLS General-Dynamic to Local-Exec transition.
167 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
168 Output_segment* tls_segment,
169 const elfcpp::Rel<32, false>&, unsigned int r_type,
170 elfcpp::Elf_types<32>::Elf_Addr value,
174 // Do a TLS Local-Dynamic to Local-Exec transition.
176 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
177 Output_segment* tls_segment,
178 const elfcpp::Rel<32, false>&, unsigned int r_type,
179 elfcpp::Elf_types<32>::Elf_Addr value,
183 // Do a TLS Initial-Exec to Local-Exec transition.
185 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
186 Output_segment* tls_segment,
187 const elfcpp::Rel<32, false>&, unsigned int r_type,
188 elfcpp::Elf_types<32>::Elf_Addr value,
192 // We need to keep track of which type of local dynamic relocation
193 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
194 enum Local_dynamic_type
201 // This is set if we should skip the next reloc, which should be a
202 // PLT32 reloc against ___tls_get_addr.
203 bool skip_call_tls_get_addr_;
204 // The type of local dynamic relocation we have seen in the section
205 // being relocated, if any.
206 Local_dynamic_type local_dynamic_type_;
209 // Adjust TLS relocation type based on the options and whether this
210 // is a local symbol.
211 static tls::Tls_optimization
212 optimize_tls_reloc(bool is_final, int r_type);
214 // Get the GOT section, creating it if necessary.
215 Output_data_got<32, false>*
216 got_section(Symbol_table*, Layout*);
218 // Create a PLT entry for a global symbol.
220 make_plt_entry(Symbol_table*, Layout*, Symbol*);
222 // Get the PLT section.
223 const Output_data_plt_i386*
226 gold_assert(this->plt_ != NULL);
230 // Get the dynamic reloc section, creating it if necessary.
232 rel_dyn_section(Layout*);
234 // Copy a relocation against a global symbol.
236 copy_reloc(const General_options*, Symbol_table*, Layout*,
237 Sized_relobj<32, false>*, unsigned int,
238 Symbol*, const elfcpp::Rel<32, false>&);
240 // Information about this specific target which we pass to the
241 // general Target structure.
242 static const Target::Target_info i386_info;
245 Output_data_got<32, false>* got_;
247 Output_data_plt_i386* plt_;
248 // The GOT PLT section.
249 Output_data_space* got_plt_;
250 // The dynamic reloc section.
251 Reloc_section* rel_dyn_;
252 // Relocs saved to avoid a COPY reloc.
253 Copy_relocs<32, false>* copy_relocs_;
254 // Space for variables copied with a COPY reloc.
255 Output_data_space* dynbss_;
258 const Target::Target_info Target_i386::i386_info =
261 false, // is_big_endian
262 elfcpp::EM_386, // machine_code
263 false, // has_make_symbol
264 false, // has_resolve
265 true, // has_code_fill
266 true, // is_default_stack_executable
267 "/usr/lib/libc.so.1", // dynamic_linker
268 0x08048000, // default_text_segment_address
269 0x1000, // abi_pagesize
270 0x1000 // common_pagesize
273 // Get the GOT section, creating it if necessary.
275 Output_data_got<32, false>*
276 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
278 if (this->got_ == NULL)
280 gold_assert(symtab != NULL && layout != NULL);
282 this->got_ = new Output_data_got<32, false>();
284 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
285 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
288 // The old GNU linker creates a .got.plt section. We just
289 // create another set of data in the .got section. Note that we
290 // always create a PLT if we create a GOT, although the PLT
292 this->got_plt_ = new Output_data_space(4);
293 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
294 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
297 // The first three entries are reserved.
298 this->got_plt_->set_space_size(3 * 4);
300 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
301 symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
303 0, 0, elfcpp::STT_OBJECT,
305 elfcpp::STV_HIDDEN, 0,
312 // Get the dynamic reloc section, creating it if necessary.
314 Target_i386::Reloc_section*
315 Target_i386::rel_dyn_section(Layout* layout)
317 if (this->rel_dyn_ == NULL)
319 gold_assert(layout != NULL);
320 this->rel_dyn_ = new Reloc_section();
321 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
322 elfcpp::SHF_ALLOC, this->rel_dyn_);
324 return this->rel_dyn_;
327 // A class to handle the PLT data.
329 class Output_data_plt_i386 : public Output_section_data
332 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
334 Output_data_plt_i386(Layout*, Output_data_space*);
336 // Add an entry to the PLT.
338 add_entry(Symbol* gsym);
340 // Return the .rel.plt section data.
343 { return this->rel_; }
347 do_adjust_output_section(Output_section* os);
350 // The size of an entry in the PLT.
351 static const int plt_entry_size = 16;
353 // The first entry in the PLT for an executable.
354 static unsigned char exec_first_plt_entry[plt_entry_size];
356 // The first entry in the PLT for a shared object.
357 static unsigned char dyn_first_plt_entry[plt_entry_size];
359 // Other entries in the PLT for an executable.
360 static unsigned char exec_plt_entry[plt_entry_size];
362 // Other entries in the PLT for a shared object.
363 static unsigned char dyn_plt_entry[plt_entry_size];
365 // Set the final size.
367 do_set_address(uint64_t, off_t)
368 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
370 // Write out the PLT data.
372 do_write(Output_file*);
374 // The reloc section.
376 // The .got.plt section.
377 Output_data_space* got_plt_;
378 // The number of PLT entries.
382 // Create the PLT section. The ordinary .got section is an argument,
383 // since we need to refer to the start. We also create our own .got
384 // section just for PLT entries.
386 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
387 Output_data_space* got_plt)
388 : Output_section_data(4), got_plt_(got_plt), count_(0)
390 this->rel_ = new Reloc_section();
391 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
392 elfcpp::SHF_ALLOC, this->rel_);
396 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
398 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
399 // linker, and so do we.
403 // Add an entry to the PLT.
406 Output_data_plt_i386::add_entry(Symbol* gsym)
408 gold_assert(!gsym->has_plt_offset());
410 // Note that when setting the PLT offset we skip the initial
411 // reserved PLT entry.
412 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
416 off_t got_offset = this->got_plt_->data_size();
418 // Every PLT entry needs a GOT entry which points back to the PLT
419 // entry (this will be changed by the dynamic linker, normally
420 // lazily when the function is called).
421 this->got_plt_->set_space_size(got_offset + 4);
423 // Every PLT entry needs a reloc.
424 gsym->set_needs_dynsym_entry();
425 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
428 // Note that we don't need to save the symbol. The contents of the
429 // PLT are independent of which symbols are used. The symbols only
430 // appear in the relocations.
433 // The first entry in the PLT for an executable.
435 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
437 0xff, 0x35, // pushl contents of memory address
438 0, 0, 0, 0, // replaced with address of .got + 4
439 0xff, 0x25, // jmp indirect
440 0, 0, 0, 0, // replaced with address of .got + 8
444 // The first entry in the PLT for a shared object.
446 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
448 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
449 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
453 // Subsequent entries in the PLT for an executable.
455 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
457 0xff, 0x25, // jmp indirect
458 0, 0, 0, 0, // replaced with address of symbol in .got
459 0x68, // pushl immediate
460 0, 0, 0, 0, // replaced with offset into relocation table
461 0xe9, // jmp relative
462 0, 0, 0, 0 // replaced with offset to start of .plt
465 // Subsequent entries in the PLT for a shared object.
467 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
469 0xff, 0xa3, // jmp *offset(%ebx)
470 0, 0, 0, 0, // replaced with offset of symbol in .got
471 0x68, // pushl immediate
472 0, 0, 0, 0, // replaced with offset into relocation table
473 0xe9, // jmp relative
474 0, 0, 0, 0 // replaced with offset to start of .plt
477 // Write out the PLT. This uses the hand-coded instructions above,
478 // and adjusts them as needed. This is all specified by the i386 ELF
479 // Processor Supplement.
482 Output_data_plt_i386::do_write(Output_file* of)
484 const off_t offset = this->offset();
485 const off_t oview_size = this->data_size();
486 unsigned char* const oview = of->get_output_view(offset, oview_size);
488 const off_t got_file_offset = this->got_plt_->offset();
489 const off_t got_size = this->got_plt_->data_size();
490 unsigned char* const got_view = of->get_output_view(got_file_offset,
493 unsigned char* pov = oview;
495 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
496 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
498 if (parameters->output_is_shared())
499 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
502 memcpy(pov, exec_first_plt_entry, plt_entry_size);
503 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
504 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
506 pov += plt_entry_size;
508 unsigned char* got_pov = got_view;
510 memset(got_pov, 0, 12);
513 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
515 unsigned int plt_offset = plt_entry_size;
516 unsigned int plt_rel_offset = 0;
517 unsigned int got_offset = 12;
518 const unsigned int count = this->count_;
519 for (unsigned int i = 0;
522 pov += plt_entry_size,
524 plt_offset += plt_entry_size,
525 plt_rel_offset += rel_size,
528 // Set and adjust the PLT entry itself.
530 if (parameters->output_is_shared())
532 memcpy(pov, dyn_plt_entry, plt_entry_size);
533 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
537 memcpy(pov, exec_plt_entry, plt_entry_size);
538 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
543 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
544 elfcpp::Swap<32, false>::writeval(pov + 12,
545 - (plt_offset + plt_entry_size));
547 // Set the entry in the GOT.
548 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
551 gold_assert(pov - oview == oview_size);
552 gold_assert(got_pov - got_view == got_size);
554 of->write_output_view(offset, oview_size, oview);
555 of->write_output_view(got_file_offset, got_size, got_view);
558 // Create a PLT entry for a global symbol.
561 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
563 if (gsym->has_plt_offset())
566 if (this->plt_ == NULL)
568 // Create the GOT sections first.
569 this->got_section(symtab, layout);
571 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
572 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
574 | elfcpp::SHF_EXECINSTR),
578 this->plt_->add_entry(gsym);
581 // Handle a relocation against a non-function symbol defined in a
582 // dynamic object. The traditional way to handle this is to generate
583 // a COPY relocation to copy the variable at runtime from the shared
584 // object into the executable's data segment. However, this is
585 // undesirable in general, as if the size of the object changes in the
586 // dynamic object, the executable will no longer work correctly. If
587 // this relocation is in a writable section, then we can create a
588 // dynamic reloc and the dynamic linker will resolve it to the correct
589 // address at runtime. However, we do not want do that if the
590 // relocation is in a read-only section, as it would prevent the
591 // readonly segment from being shared. And if we have to eventually
592 // generate a COPY reloc, then any dynamic relocations will be
593 // useless. So this means that if this is a writable section, we need
594 // to save the relocation until we see whether we have to create a
595 // COPY relocation for this symbol for any other relocation.
598 Target_i386::copy_reloc(const General_options* options,
599 Symbol_table* symtab,
601 Sized_relobj<32, false>* object,
602 unsigned int data_shndx, Symbol* gsym,
603 const elfcpp::Rel<32, false>& rel)
605 Sized_symbol<32>* ssym;
606 ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
609 if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
612 // So far we do not need a COPY reloc. Save this relocation.
613 // If it turns out that we never need a COPY reloc for this
614 // symbol, then we will emit the relocation.
615 if (this->copy_relocs_ == NULL)
616 this->copy_relocs_ = new Copy_relocs<32, false>();
617 this->copy_relocs_->save(ssym, object, data_shndx, rel);
621 // Allocate space for this symbol in the .bss section.
623 elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
625 // There is no defined way to determine the required alignment
626 // of the symbol. We pick the alignment based on the size. We
627 // set an arbitrary maximum of 256.
629 for (align = 1; align < 512; align <<= 1)
630 if ((symsize & align) != 0)
633 if (this->dynbss_ == NULL)
635 this->dynbss_ = new Output_data_space(align);
636 layout->add_output_section_data(".bss",
639 | elfcpp::SHF_WRITE),
643 Output_data_space* dynbss = this->dynbss_;
645 if (align > dynbss->addralign())
646 dynbss->set_space_alignment(align);
648 off_t dynbss_size = dynbss->data_size();
649 dynbss_size = align_address(dynbss_size, align);
650 off_t offset = dynbss_size;
651 dynbss->set_space_size(dynbss_size + symsize);
653 symtab->define_with_copy_reloc(this, ssym, dynbss, offset);
655 // Add the COPY reloc.
656 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
657 rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
661 // Optimize the TLS relocation type based on what we know about the
662 // symbol. IS_FINAL is true if the final address of this symbol is
663 // known at link time.
665 tls::Tls_optimization
666 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
668 // If we are generating a shared library, then we can't do anything
670 if (parameters->output_is_shared())
671 return tls::TLSOPT_NONE;
675 case elfcpp::R_386_TLS_GD:
676 case elfcpp::R_386_TLS_GOTDESC:
677 case elfcpp::R_386_TLS_DESC_CALL:
678 // These are General-Dynamic which permits fully general TLS
679 // access. Since we know that we are generating an executable,
680 // we can convert this to Initial-Exec. If we also know that
681 // this is a local symbol, we can further switch to Local-Exec.
683 return tls::TLSOPT_TO_LE;
684 return tls::TLSOPT_TO_IE;
686 case elfcpp::R_386_TLS_LDM:
687 // This is Local-Dynamic, which refers to a local symbol in the
688 // dynamic TLS block. Since we know that we generating an
689 // executable, we can switch to Local-Exec.
690 return tls::TLSOPT_TO_LE;
692 case elfcpp::R_386_TLS_LDO_32:
693 // Another type of Local-Dynamic relocation.
694 return tls::TLSOPT_TO_LE;
696 case elfcpp::R_386_TLS_IE:
697 case elfcpp::R_386_TLS_GOTIE:
698 case elfcpp::R_386_TLS_IE_32:
699 // These are Initial-Exec relocs which get the thread offset
700 // from the GOT. If we know that we are linking against the
701 // local symbol, we can switch to Local-Exec, which links the
702 // thread offset into the instruction.
704 return tls::TLSOPT_TO_LE;
705 return tls::TLSOPT_NONE;
707 case elfcpp::R_386_TLS_LE:
708 case elfcpp::R_386_TLS_LE_32:
709 // When we already have Local-Exec, there is nothing further we
711 return tls::TLSOPT_NONE;
718 // Report an unsupported relocation against a local symbol.
721 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
724 gold_error(_("%s: unsupported reloc %u against local symbol"),
725 object->name().c_str(), r_type);
728 // Scan a relocation for a local symbol.
731 Target_i386::Scan::local(const General_options&,
732 Symbol_table* symtab,
735 Sized_relobj<32, false>* object,
736 unsigned int data_shndx,
737 const elfcpp::Rel<32, false>& reloc,
739 const elfcpp::Sym<32, false>&)
743 case elfcpp::R_386_NONE:
744 case elfcpp::R_386_GNU_VTINHERIT:
745 case elfcpp::R_386_GNU_VTENTRY:
748 case elfcpp::R_386_32:
749 case elfcpp::R_386_16:
750 case elfcpp::R_386_8:
751 // If building a shared library (or a position-independent
752 // executable), we need to create a dynamic relocation for
753 // this location. The relocation applied at link time will
754 // apply the link-time value, so we flag the location with
755 // an R_386_RELATIVE relocation so the dynamic loader can
756 // relocate it easily.
757 if (parameters->output_is_position_independent())
759 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
760 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, data_shndx,
761 reloc.get_r_offset());
765 case elfcpp::R_386_PC32:
766 case elfcpp::R_386_PC16:
767 case elfcpp::R_386_PC8:
770 case elfcpp::R_386_PLT32:
771 // Since we know this is a local symbol, we can handle this as a
775 case elfcpp::R_386_GOTOFF:
776 case elfcpp::R_386_GOTPC:
777 // We need a GOT section.
778 target->got_section(symtab, layout);
781 case elfcpp::R_386_GOT32:
783 // The symbol requires a GOT entry.
784 Output_data_got<32, false>* got = target->got_section(symtab, layout);
785 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
786 if (got->add_local(object, r_sym))
788 // If we are generating a shared object, we need to add a
789 // dynamic RELATIVE relocation for this symbol.
790 if (parameters->output_is_position_independent())
792 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
793 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
794 data_shndx, reloc.get_r_offset());
800 // These are relocations which should only be seen by the
801 // dynamic linker, and should never be seen here.
802 case elfcpp::R_386_COPY:
803 case elfcpp::R_386_GLOB_DAT:
804 case elfcpp::R_386_JUMP_SLOT:
805 case elfcpp::R_386_RELATIVE:
806 case elfcpp::R_386_TLS_TPOFF:
807 case elfcpp::R_386_TLS_DTPMOD32:
808 case elfcpp::R_386_TLS_DTPOFF32:
809 case elfcpp::R_386_TLS_TPOFF32:
810 case elfcpp::R_386_TLS_DESC:
811 gold_error(_("%s: unexpected reloc %u in object file"),
812 object->name().c_str(), r_type);
815 // These are initial TLS relocs, which are expected when
817 case elfcpp::R_386_TLS_GD: // Global-dynamic
818 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
819 case elfcpp::R_386_TLS_DESC_CALL:
820 case elfcpp::R_386_TLS_LDM: // Local-dynamic
821 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
822 case elfcpp::R_386_TLS_IE: // Initial-exec
823 case elfcpp::R_386_TLS_IE_32:
824 case elfcpp::R_386_TLS_GOTIE:
825 case elfcpp::R_386_TLS_LE: // Local-exec
826 case elfcpp::R_386_TLS_LE_32:
828 bool output_is_shared = parameters->output_is_shared();
829 const tls::Tls_optimization optimized_type
830 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
833 case elfcpp::R_386_TLS_GD: // Global-dynamic
834 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
835 case elfcpp::R_386_TLS_DESC_CALL:
836 // FIXME: If not relaxing to LE, we need to generate
837 // DTPMOD32 and DTPOFF32 relocs.
838 if (optimized_type != tls::TLSOPT_TO_LE)
839 unsupported_reloc_local(object, r_type);
842 case elfcpp::R_386_TLS_LDM: // Local-dynamic
843 // FIXME: If not relaxing to LE, we need to generate a
845 if (optimized_type != tls::TLSOPT_TO_LE)
846 unsupported_reloc_local(object, r_type);
849 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
852 case elfcpp::R_386_TLS_IE: // Initial-exec
853 case elfcpp::R_386_TLS_IE_32:
854 case elfcpp::R_386_TLS_GOTIE:
855 // FIXME: If not relaxing to LE, we need to generate a
856 // TPOFF or TPOFF32 reloc.
857 if (optimized_type != tls::TLSOPT_TO_LE)
858 unsupported_reloc_local(object, r_type);
861 case elfcpp::R_386_TLS_LE: // Local-exec
862 case elfcpp::R_386_TLS_LE_32:
863 // FIXME: If generating a shared object, we need to copy
864 // this relocation into the object.
865 gold_assert(!output_is_shared);
874 case elfcpp::R_386_32PLT:
875 case elfcpp::R_386_TLS_GD_32:
876 case elfcpp::R_386_TLS_GD_PUSH:
877 case elfcpp::R_386_TLS_GD_CALL:
878 case elfcpp::R_386_TLS_GD_POP:
879 case elfcpp::R_386_TLS_LDM_32:
880 case elfcpp::R_386_TLS_LDM_PUSH:
881 case elfcpp::R_386_TLS_LDM_CALL:
882 case elfcpp::R_386_TLS_LDM_POP:
883 case elfcpp::R_386_USED_BY_INTEL_200:
885 unsupported_reloc_local(object, r_type);
890 // Report an unsupported relocation against a global symbol.
893 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
897 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
898 object->name().c_str(), r_type, gsym->name());
901 // Scan a relocation for a global symbol.
904 Target_i386::Scan::global(const General_options& options,
905 Symbol_table* symtab,
908 Sized_relobj<32, false>* object,
909 unsigned int data_shndx,
910 const elfcpp::Rel<32, false>& reloc,
916 case elfcpp::R_386_NONE:
917 case elfcpp::R_386_GNU_VTINHERIT:
918 case elfcpp::R_386_GNU_VTENTRY:
921 case elfcpp::R_386_32:
922 case elfcpp::R_386_PC32:
923 case elfcpp::R_386_16:
924 case elfcpp::R_386_PC16:
925 case elfcpp::R_386_8:
926 case elfcpp::R_386_PC8:
927 if (gsym->is_from_dynobj()
928 || (parameters->output_is_shared()
929 && gsym->is_preemptible()))
931 // (a) This symbol is defined in a dynamic object. If it is a
932 // function, we make a PLT entry. Otherwise we need to
933 // either generate a COPY reloc or copy this reloc.
934 // (b) We are building a shared object and this symbol is
935 // preemptible. If it is a function, we make a PLT entry.
936 // Otherwise, we copy the reloc. We do not make COPY relocs
937 // in shared objects.
938 if (gsym->type() == elfcpp::STT_FUNC)
940 target->make_plt_entry(symtab, layout, gsym);
942 // If this is not a PC relative reference, then we may
943 // be taking the address of the function. In that case
944 // we need to set the entry in the dynamic symbol table
945 // to the address of the PLT entry.
946 if (r_type != elfcpp::R_386_PC32
947 && r_type != elfcpp::R_386_PC16
948 && r_type != elfcpp::R_386_PC8
949 && gsym->is_from_dynobj())
950 gsym->set_needs_dynsym_value();
952 else if (parameters->output_is_shared())
954 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
955 rel_dyn->add_global(gsym, r_type, object, data_shndx,
956 reloc.get_r_offset());
959 target->copy_reloc(&options, symtab, layout, object, data_shndx,
965 case elfcpp::R_386_GOT32:
967 // The symbol requires a GOT entry.
968 Output_data_got<32, false>* got = target->got_section(symtab, layout);
969 if (got->add_global(gsym))
971 // If this symbol is not fully resolved, we need to add a
972 // dynamic relocation for it.
973 if (!gsym->final_value_is_known())
975 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
976 rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
983 case elfcpp::R_386_PLT32:
984 // If the symbol is fully resolved, this is just a PC32 reloc.
985 // Otherwise we need a PLT entry.
986 if (gsym->final_value_is_known())
988 // If building a shared library, we can also skip the PLT entry
989 // if the symbol is defined in the output file and is protected
991 if (gsym->is_defined()
992 && !gsym->is_from_dynobj()
993 && !gsym->is_preemptible())
995 target->make_plt_entry(symtab, layout, gsym);
998 case elfcpp::R_386_GOTOFF:
999 case elfcpp::R_386_GOTPC:
1000 // We need a GOT section.
1001 target->got_section(symtab, layout);
1004 // These are relocations which should only be seen by the
1005 // dynamic linker, and should never be seen here.
1006 case elfcpp::R_386_COPY:
1007 case elfcpp::R_386_GLOB_DAT:
1008 case elfcpp::R_386_JUMP_SLOT:
1009 case elfcpp::R_386_RELATIVE:
1010 case elfcpp::R_386_TLS_TPOFF:
1011 case elfcpp::R_386_TLS_DTPMOD32:
1012 case elfcpp::R_386_TLS_DTPOFF32:
1013 case elfcpp::R_386_TLS_TPOFF32:
1014 case elfcpp::R_386_TLS_DESC:
1015 gold_error(_("%s: unexpected reloc %u in object file"),
1016 object->name().c_str(), r_type);
1019 // These are initial tls relocs, which are expected when
1021 case elfcpp::R_386_TLS_GD: // Global-dynamic
1022 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1023 case elfcpp::R_386_TLS_DESC_CALL:
1024 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1025 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1026 case elfcpp::R_386_TLS_IE: // Initial-exec
1027 case elfcpp::R_386_TLS_IE_32:
1028 case elfcpp::R_386_TLS_GOTIE:
1029 case elfcpp::R_386_TLS_LE: // Local-exec
1030 case elfcpp::R_386_TLS_LE_32:
1032 const bool is_final = gsym->final_value_is_known();
1033 const tls::Tls_optimization optimized_type
1034 = Target_i386::optimize_tls_reloc(is_final, r_type);
1037 case elfcpp::R_386_TLS_GD: // Global-dynamic
1038 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1039 case elfcpp::R_386_TLS_DESC_CALL:
1040 // FIXME: If not relaxing to LE, we need to generate
1041 // DTPMOD32 and DTPOFF32 relocs.
1042 if (optimized_type != tls::TLSOPT_TO_LE)
1043 unsupported_reloc_global(object, r_type, gsym);
1046 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1047 // FIXME: If not relaxing to LE, we need to generate a
1049 if (optimized_type != tls::TLSOPT_TO_LE)
1050 unsupported_reloc_global(object, r_type, gsym);
1053 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1056 case elfcpp::R_386_TLS_IE: // Initial-exec
1057 case elfcpp::R_386_TLS_IE_32:
1058 case elfcpp::R_386_TLS_GOTIE:
1059 // FIXME: If not relaxing to LE, we need to generate a
1060 // TPOFF or TPOFF32 reloc.
1061 if (optimized_type != tls::TLSOPT_TO_LE)
1062 unsupported_reloc_global(object, r_type, gsym);
1065 case elfcpp::R_386_TLS_LE: // Local-exec
1066 case elfcpp::R_386_TLS_LE_32:
1067 // FIXME: If generating a shared object, we need to copy
1068 // this relocation into the object.
1069 gold_assert(!parameters->output_is_shared());
1078 case elfcpp::R_386_32PLT:
1079 case elfcpp::R_386_TLS_GD_32:
1080 case elfcpp::R_386_TLS_GD_PUSH:
1081 case elfcpp::R_386_TLS_GD_CALL:
1082 case elfcpp::R_386_TLS_GD_POP:
1083 case elfcpp::R_386_TLS_LDM_32:
1084 case elfcpp::R_386_TLS_LDM_PUSH:
1085 case elfcpp::R_386_TLS_LDM_CALL:
1086 case elfcpp::R_386_TLS_LDM_POP:
1087 case elfcpp::R_386_USED_BY_INTEL_200:
1089 unsupported_reloc_global(object, r_type, gsym);
1094 // Scan relocations for a section.
1097 Target_i386::scan_relocs(const General_options& options,
1098 Symbol_table* symtab,
1100 Sized_relobj<32, false>* object,
1101 unsigned int data_shndx,
1102 unsigned int sh_type,
1103 const unsigned char* prelocs,
1105 size_t local_symbol_count,
1106 const unsigned char* plocal_symbols,
1107 Symbol** global_symbols)
1109 if (sh_type == elfcpp::SHT_RELA)
1111 gold_error(_("%s: unsupported RELA reloc section"),
1112 object->name().c_str());
1116 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1131 // Finalize the sections.
1134 Target_i386::do_finalize_sections(Layout* layout)
1136 // Fill in some more dynamic tags.
1137 Output_data_dynamic* const odyn = layout->dynamic_data();
1140 if (this->got_plt_ != NULL)
1141 odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1143 if (this->plt_ != NULL)
1145 const Output_data* od = this->plt_->rel_plt();
1146 odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1147 odyn->add_section_address(elfcpp::DT_JMPREL, od);
1148 odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1151 if (this->rel_dyn_ != NULL)
1153 const Output_data* od = this->rel_dyn_;
1154 odyn->add_section_address(elfcpp::DT_REL, od);
1155 odyn->add_section_size(elfcpp::DT_RELSZ, od);
1156 odyn->add_constant(elfcpp::DT_RELENT,
1157 elfcpp::Elf_sizes<32>::rel_size);
1160 if (!parameters->output_is_shared())
1162 // The value of the DT_DEBUG tag is filled in by the dynamic
1163 // linker at run time, and used by the debugger.
1164 odyn->add_constant(elfcpp::DT_DEBUG, 0);
1168 // Emit any relocs we saved in an attempt to avoid generating COPY
1170 if (this->copy_relocs_ == NULL)
1172 if (this->copy_relocs_->any_to_emit())
1174 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1175 this->copy_relocs_->emit(rel_dyn);
1177 delete this->copy_relocs_;
1178 this->copy_relocs_ = NULL;
1181 // Perform a relocation.
1184 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1185 Target_i386* target,
1187 const elfcpp::Rel<32, false>& rel,
1188 unsigned int r_type,
1189 const Sized_symbol<32>* gsym,
1190 const Symbol_value<32>* psymval,
1191 unsigned char* view,
1192 elfcpp::Elf_types<32>::Elf_Addr address,
1195 if (this->skip_call_tls_get_addr_)
1197 if (r_type != elfcpp::R_386_PLT32
1199 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1200 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1201 _("missing expected TLS relocation"));
1204 this->skip_call_tls_get_addr_ = false;
1209 // Pick the value to use for symbols defined in shared objects.
1210 Symbol_value<32> symval;
1212 && (gsym->is_from_dynobj()
1213 || (parameters->output_is_shared()
1214 && gsym->is_preemptible()))
1215 && gsym->has_plt_offset())
1217 symval.set_output_value(target->plt_section()->address()
1218 + gsym->plt_offset());
1222 const Sized_relobj<32, false>* object = relinfo->object;
1224 // Get the GOT offset if needed.
1225 bool have_got_offset = false;
1226 unsigned int got_offset = 0;
1229 case elfcpp::R_386_GOT32:
1232 gold_assert(gsym->has_got_offset());
1233 got_offset = gsym->got_offset();
1237 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1238 got_offset = object->local_got_offset(r_sym);
1240 have_got_offset = true;
1249 case elfcpp::R_386_NONE:
1250 case elfcpp::R_386_GNU_VTINHERIT:
1251 case elfcpp::R_386_GNU_VTENTRY:
1254 case elfcpp::R_386_32:
1255 Relocate_functions<32, false>::rel32(view, object, psymval);
1258 case elfcpp::R_386_PC32:
1259 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1262 case elfcpp::R_386_16:
1263 Relocate_functions<32, false>::rel16(view, object, psymval);
1266 case elfcpp::R_386_PC16:
1267 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1270 case elfcpp::R_386_8:
1271 Relocate_functions<32, false>::rel8(view, object, psymval);
1274 case elfcpp::R_386_PC8:
1275 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1278 case elfcpp::R_386_PLT32:
1279 gold_assert(gsym == NULL
1280 || gsym->has_plt_offset()
1281 || gsym->final_value_is_known());
1282 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1285 case elfcpp::R_386_GOT32:
1286 gold_assert(have_got_offset);
1287 Relocate_functions<32, false>::rel32(view, got_offset);
1290 case elfcpp::R_386_GOTOFF:
1292 elfcpp::Elf_types<32>::Elf_Addr value;
1293 value = (psymval->value(object, 0)
1294 - target->got_section(NULL, NULL)->address());
1295 Relocate_functions<32, false>::rel32(view, value);
1299 case elfcpp::R_386_GOTPC:
1301 elfcpp::Elf_types<32>::Elf_Addr value;
1302 value = target->got_section(NULL, NULL)->address();
1303 Relocate_functions<32, false>::pcrel32(view, value, address);
1307 case elfcpp::R_386_COPY:
1308 case elfcpp::R_386_GLOB_DAT:
1309 case elfcpp::R_386_JUMP_SLOT:
1310 case elfcpp::R_386_RELATIVE:
1311 // These are outstanding tls relocs, which are unexpected when
1313 case elfcpp::R_386_TLS_TPOFF:
1314 case elfcpp::R_386_TLS_DTPMOD32:
1315 case elfcpp::R_386_TLS_DTPOFF32:
1316 case elfcpp::R_386_TLS_TPOFF32:
1317 case elfcpp::R_386_TLS_DESC:
1318 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1319 _("unexpected reloc %u in object file"),
1323 // These are initial tls relocs, which are expected when
1325 case elfcpp::R_386_TLS_GD: // Global-dynamic
1326 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1327 case elfcpp::R_386_TLS_DESC_CALL:
1328 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1329 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1330 case elfcpp::R_386_TLS_IE: // Initial-exec
1331 case elfcpp::R_386_TLS_IE_32:
1332 case elfcpp::R_386_TLS_GOTIE:
1333 case elfcpp::R_386_TLS_LE: // Local-exec
1334 case elfcpp::R_386_TLS_LE_32:
1335 this->relocate_tls(relinfo, relnum, rel, r_type, gsym, psymval, view,
1336 address, view_size);
1339 case elfcpp::R_386_32PLT:
1340 case elfcpp::R_386_TLS_GD_32:
1341 case elfcpp::R_386_TLS_GD_PUSH:
1342 case elfcpp::R_386_TLS_GD_CALL:
1343 case elfcpp::R_386_TLS_GD_POP:
1344 case elfcpp::R_386_TLS_LDM_32:
1345 case elfcpp::R_386_TLS_LDM_PUSH:
1346 case elfcpp::R_386_TLS_LDM_CALL:
1347 case elfcpp::R_386_TLS_LDM_POP:
1348 case elfcpp::R_386_USED_BY_INTEL_200:
1350 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1351 _("unsupported reloc %u"),
1359 // Perform a TLS relocation.
1362 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1364 const elfcpp::Rel<32, false>& rel,
1365 unsigned int r_type,
1366 const Sized_symbol<32>* gsym,
1367 const Symbol_value<32>* psymval,
1368 unsigned char* view,
1369 elfcpp::Elf_types<32>::Elf_Addr,
1372 Output_segment* tls_segment = relinfo->layout->tls_segment();
1373 if (tls_segment == NULL)
1375 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1376 _("TLS reloc but no TLS segment"));
1380 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(relinfo->object, 0);
1382 const bool is_final = (gsym == NULL
1383 ? !parameters->output_is_position_independent()
1384 : gsym->final_value_is_known());
1385 const tls::Tls_optimization optimized_type
1386 = Target_i386::optimize_tls_reloc(is_final, r_type);
1389 case elfcpp::R_386_TLS_GD: // Global-dynamic
1390 if (optimized_type == tls::TLSOPT_TO_LE)
1392 this->tls_gd_to_le(relinfo, relnum, tls_segment,
1393 rel, r_type, value, view,
1397 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1398 _("unsupported reloc %u"),
1402 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1403 case elfcpp::R_386_TLS_DESC_CALL:
1404 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1405 _("unsupported reloc %u"),
1409 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1410 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1412 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1413 _("both SUN and GNU model "
1414 "TLS relocations"));
1417 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1418 if (optimized_type == tls::TLSOPT_TO_LE)
1420 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1421 value, view, view_size);
1424 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1425 _("unsupported reloc %u"),
1429 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1430 // This reloc can appear in debugging sections, in which case we
1431 // won't see the TLS_LDM reloc. The local_dynamic_type field
1433 if (optimized_type != tls::TLSOPT_TO_LE
1434 || this->local_dynamic_type_ == LOCAL_DYNAMIC_NONE)
1435 value = value - tls_segment->vaddr();
1436 else if (this->local_dynamic_type_ == LOCAL_DYNAMIC_GNU)
1437 value = value - (tls_segment->vaddr() + tls_segment->memsz());
1439 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1440 Relocate_functions<32, false>::rel32(view, value);
1443 case elfcpp::R_386_TLS_IE: // Initial-exec
1444 case elfcpp::R_386_TLS_GOTIE:
1445 case elfcpp::R_386_TLS_IE_32:
1446 if (optimized_type == tls::TLSOPT_TO_LE)
1448 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1449 rel, r_type, value, view,
1453 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1454 _("unsupported reloc %u"),
1458 case elfcpp::R_386_TLS_LE: // Local-exec
1459 value = value - (tls_segment->vaddr() + tls_segment->memsz());
1460 Relocate_functions<32, false>::rel32(view, value);
1463 case elfcpp::R_386_TLS_LE_32:
1464 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1465 Relocate_functions<32, false>::rel32(view, value);
1470 // Do a relocation in which we convert a TLS General-Dynamic to a
1474 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1476 Output_segment* tls_segment,
1477 const elfcpp::Rel<32, false>& rel,
1479 elfcpp::Elf_types<32>::Elf_Addr value,
1480 unsigned char* view,
1483 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1484 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1485 // leal foo(%reg),%eax; call ___tls_get_addr
1486 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1488 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1489 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1491 unsigned char op1 = view[-1];
1492 unsigned char op2 = view[-2];
1494 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1495 op2 == 0x8d || op2 == 0x04);
1496 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1502 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1503 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1504 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1505 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1506 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1510 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1511 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1512 if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1515 // There is a trailing nop. Use the size byte subl.
1516 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1521 // Use the five byte subl.
1522 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1526 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1527 Relocate_functions<32, false>::rel32(view + roff, value);
1529 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1531 this->skip_call_tls_get_addr_ = true;
1534 // Do a relocation in which we convert a TLS Local-Dynamic to a
1538 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
1541 const elfcpp::Rel<32, false>& rel,
1543 elfcpp::Elf_types<32>::Elf_Addr,
1544 unsigned char* view,
1547 // leal foo(%reg), %eax; call ___tls_get_addr
1548 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1550 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1551 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1553 // FIXME: Does this test really always pass?
1554 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1555 view[-2] == 0x8d && view[-1] == 0x83);
1557 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1559 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1561 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1563 this->skip_call_tls_get_addr_ = true;
1566 // Do a relocation in which we convert a TLS Initial-Exec to a
1570 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1572 Output_segment* tls_segment,
1573 const elfcpp::Rel<32, false>& rel,
1574 unsigned int r_type,
1575 elfcpp::Elf_types<32>::Elf_Addr value,
1576 unsigned char* view,
1579 // We have to actually change the instructions, which means that we
1580 // need to examine the opcodes to figure out which instruction we
1582 if (r_type == elfcpp::R_386_TLS_IE)
1584 // movl %gs:XX,%eax ==> movl $YY,%eax
1585 // movl %gs:XX,%reg ==> movl $YY,%reg
1586 // addl %gs:XX,%reg ==> addl $YY,%reg
1587 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
1588 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1590 unsigned char op1 = view[-1];
1593 // movl XX,%eax ==> movl $YY,%eax
1598 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1600 unsigned char op2 = view[-2];
1603 // movl XX,%reg ==> movl $YY,%reg
1604 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1605 (op1 & 0xc7) == 0x05);
1607 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1609 else if (op2 == 0x03)
1611 // addl XX,%reg ==> addl $YY,%reg
1612 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1613 (op1 & 0xc7) == 0x05);
1615 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1618 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
1623 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1624 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1625 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1626 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1627 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1629 unsigned char op1 = view[-1];
1630 unsigned char op2 = view[-2];
1631 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1632 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
1635 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1637 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1639 else if (op2 == 0x2b)
1641 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1643 view[-1] = 0xe8 | ((op1 >> 3) & 7);
1645 else if (op2 == 0x03)
1647 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1649 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1652 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
1655 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1656 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
1659 Relocate_functions<32, false>::rel32(view, value);
1662 // Relocate section data.
1665 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
1666 unsigned int sh_type,
1667 const unsigned char* prelocs,
1669 unsigned char* view,
1670 elfcpp::Elf_types<32>::Elf_Addr address,
1673 gold_assert(sh_type == elfcpp::SHT_REL);
1675 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
1676 Target_i386::Relocate>(
1686 // Return the value to use for a dynamic which requires special
1687 // treatment. This is how we support equality comparisons of function
1688 // pointers across shared library boundaries, as described in the
1689 // processor specific ABI supplement.
1692 Target_i386::do_dynsym_value(const Symbol* gsym) const
1694 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
1695 return this->plt_section()->address() + gsym->plt_offset();
1698 // Return a string used to fill a code section with nops to take up
1699 // the specified length.
1702 Target_i386::do_code_fill(off_t length)
1706 // Build a jmp instruction to skip over the bytes.
1707 unsigned char jmp[5];
1709 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
1710 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1711 + std::string(length - 5, '\0'));
1714 // Nop sequences of various lengths.
1715 const char nop1[1] = { 0x90 }; // nop
1716 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
1717 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1718 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1719 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1720 0x00 }; // leal 0(%esi,1),%esi
1721 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1723 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1725 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1726 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1727 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1728 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1730 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1731 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1733 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1734 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1736 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1737 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1738 0x00, 0x00, 0x00, 0x00 };
1739 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1740 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1741 0x27, 0x00, 0x00, 0x00,
1743 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1744 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1745 0xbc, 0x27, 0x00, 0x00,
1747 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1748 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1749 0x90, 0x90, 0x90, 0x90,
1752 const char* nops[16] = {
1754 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
1755 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
1758 return std::string(nops[length], length);
1761 // The selector for i386 object files.
1763 class Target_selector_i386 : public Target_selector
1766 Target_selector_i386()
1767 : Target_selector(elfcpp::EM_386, 32, false)
1771 recognize(int machine, int osabi, int abiversion);
1774 Target_i386* target_;
1777 // Recognize an i386 object file when we already know that the machine
1778 // number is EM_386.
1781 Target_selector_i386::recognize(int, int, int)
1783 if (this->target_ == NULL)
1784 this->target_ = new Target_i386();
1785 return this->target_;
1788 Target_selector_i386 target_selector_i386;
1790 } // End anonymous namespace.