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);
100 // Return the size of the GOT section.
104 gold_assert(this->got_ != NULL);
105 return this->got_->data_size();
109 // The class which scans relocations.
113 local(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,
118 const elfcpp::Sym<32, false>& lsym);
121 global(const General_options& options, Symbol_table* symtab,
122 Layout* layout, Target_i386* target,
123 Sized_relobj<32, false>* object,
124 unsigned int data_shndx,
125 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
129 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
132 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
136 // The class which implements relocation.
141 : skip_call_tls_get_addr_(false),
142 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
147 if (this->skip_call_tls_get_addr_)
149 // FIXME: This needs to specify the location somehow.
150 gold_error(_("missing expected TLS relocation"));
154 // Return whether the static relocation needs to be applied.
156 should_apply_static_reloc(const Sized_symbol<32>* gsym,
160 // Do a relocation. Return false if the caller should not issue
161 // any warnings about this relocation.
163 relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
164 const elfcpp::Rel<32, false>&,
165 unsigned int r_type, const Sized_symbol<32>*,
166 const Symbol_value<32>*,
167 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
171 // Do a TLS relocation.
173 relocate_tls(const Relocate_info<32, false>*, size_t relnum,
174 const elfcpp::Rel<32, false>&,
175 unsigned int r_type, const Sized_symbol<32>*,
176 const Symbol_value<32>*,
177 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
179 // Do a TLS General-Dynamic to Local-Exec transition.
181 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
182 Output_segment* tls_segment,
183 const elfcpp::Rel<32, false>&, unsigned int r_type,
184 elfcpp::Elf_types<32>::Elf_Addr value,
188 // Do a TLS Local-Dynamic to Local-Exec transition.
190 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
191 Output_segment* tls_segment,
192 const elfcpp::Rel<32, false>&, unsigned int r_type,
193 elfcpp::Elf_types<32>::Elf_Addr value,
197 // Do a TLS Initial-Exec to Local-Exec transition.
199 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
200 Output_segment* tls_segment,
201 const elfcpp::Rel<32, false>&, unsigned int r_type,
202 elfcpp::Elf_types<32>::Elf_Addr value,
206 // We need to keep track of which type of local dynamic relocation
207 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
208 enum Local_dynamic_type
215 // This is set if we should skip the next reloc, which should be a
216 // PLT32 reloc against ___tls_get_addr.
217 bool skip_call_tls_get_addr_;
218 // The type of local dynamic relocation we have seen in the section
219 // being relocated, if any.
220 Local_dynamic_type local_dynamic_type_;
223 // Adjust TLS relocation type based on the options and whether this
224 // is a local symbol.
225 static tls::Tls_optimization
226 optimize_tls_reloc(bool is_final, int r_type);
228 // Get the GOT section, creating it if necessary.
229 Output_data_got<32, false>*
230 got_section(Symbol_table*, Layout*);
232 // Get the GOT PLT section.
234 got_plt_section() const
236 gold_assert(this->got_plt_ != NULL);
237 return this->got_plt_;
240 // Create a PLT entry for a global symbol.
242 make_plt_entry(Symbol_table*, Layout*, Symbol*);
244 // Get the PLT section.
245 const Output_data_plt_i386*
248 gold_assert(this->plt_ != NULL);
252 // Get the dynamic reloc section, creating it if necessary.
254 rel_dyn_section(Layout*);
256 // Copy a relocation against a global symbol.
258 copy_reloc(const General_options*, Symbol_table*, Layout*,
259 Sized_relobj<32, false>*, unsigned int,
260 Symbol*, const elfcpp::Rel<32, false>&);
262 // Information about this specific target which we pass to the
263 // general Target structure.
264 static const Target::Target_info i386_info;
267 Output_data_got<32, false>* got_;
269 Output_data_plt_i386* plt_;
270 // The GOT PLT section.
271 Output_data_space* got_plt_;
272 // The dynamic reloc section.
273 Reloc_section* rel_dyn_;
274 // Relocs saved to avoid a COPY reloc.
275 Copy_relocs<32, false>* copy_relocs_;
276 // Space for variables copied with a COPY reloc.
277 Output_data_space* dynbss_;
280 const Target::Target_info Target_i386::i386_info =
283 false, // is_big_endian
284 elfcpp::EM_386, // machine_code
285 false, // has_make_symbol
286 false, // has_resolve
287 true, // has_code_fill
288 true, // is_default_stack_executable
289 "/usr/lib/libc.so.1", // dynamic_linker
290 0x08048000, // default_text_segment_address
291 0x1000, // abi_pagesize
292 0x1000 // common_pagesize
295 // Get the GOT section, creating it if necessary.
297 Output_data_got<32, false>*
298 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
300 if (this->got_ == NULL)
302 gold_assert(symtab != NULL && layout != NULL);
304 this->got_ = new Output_data_got<32, false>();
306 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
307 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
310 // The old GNU linker creates a .got.plt section. We just
311 // create another set of data in the .got section. Note that we
312 // always create a PLT if we create a GOT, although the PLT
314 this->got_plt_ = new Output_data_space(4);
315 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
316 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
319 // The first three entries are reserved.
320 this->got_plt_->set_space_size(3 * 4);
322 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
323 symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
325 0, 0, elfcpp::STT_OBJECT,
327 elfcpp::STV_HIDDEN, 0,
334 // Get the dynamic reloc section, creating it if necessary.
336 Target_i386::Reloc_section*
337 Target_i386::rel_dyn_section(Layout* layout)
339 if (this->rel_dyn_ == NULL)
341 gold_assert(layout != NULL);
342 this->rel_dyn_ = new Reloc_section();
343 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
344 elfcpp::SHF_ALLOC, this->rel_dyn_);
346 return this->rel_dyn_;
349 // A class to handle the PLT data.
351 class Output_data_plt_i386 : public Output_section_data
354 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
356 Output_data_plt_i386(Layout*, Output_data_space*);
358 // Add an entry to the PLT.
360 add_entry(Symbol* gsym);
362 // Return the .rel.plt section data.
365 { return this->rel_; }
369 do_adjust_output_section(Output_section* os);
372 // The size of an entry in the PLT.
373 static const int plt_entry_size = 16;
375 // The first entry in the PLT for an executable.
376 static unsigned char exec_first_plt_entry[plt_entry_size];
378 // The first entry in the PLT for a shared object.
379 static unsigned char dyn_first_plt_entry[plt_entry_size];
381 // Other entries in the PLT for an executable.
382 static unsigned char exec_plt_entry[plt_entry_size];
384 // Other entries in the PLT for a shared object.
385 static unsigned char dyn_plt_entry[plt_entry_size];
387 // Set the final size.
389 do_set_address(uint64_t, off_t)
390 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
392 // Write out the PLT data.
394 do_write(Output_file*);
396 // The reloc section.
398 // The .got.plt section.
399 Output_data_space* got_plt_;
400 // The number of PLT entries.
404 // Create the PLT section. The ordinary .got section is an argument,
405 // since we need to refer to the start. We also create our own .got
406 // section just for PLT entries.
408 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
409 Output_data_space* got_plt)
410 : Output_section_data(4), got_plt_(got_plt), count_(0)
412 this->rel_ = new Reloc_section();
413 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
414 elfcpp::SHF_ALLOC, this->rel_);
418 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
420 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
421 // linker, and so do we.
425 // Add an entry to the PLT.
428 Output_data_plt_i386::add_entry(Symbol* gsym)
430 gold_assert(!gsym->has_plt_offset());
432 // Note that when setting the PLT offset we skip the initial
433 // reserved PLT entry.
434 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
438 off_t got_offset = this->got_plt_->data_size();
440 // Every PLT entry needs a GOT entry which points back to the PLT
441 // entry (this will be changed by the dynamic linker, normally
442 // lazily when the function is called).
443 this->got_plt_->set_space_size(got_offset + 4);
445 // Every PLT entry needs a reloc.
446 gsym->set_needs_dynsym_entry();
447 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
450 // Note that we don't need to save the symbol. The contents of the
451 // PLT are independent of which symbols are used. The symbols only
452 // appear in the relocations.
455 // The first entry in the PLT for an executable.
457 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
459 0xff, 0x35, // pushl contents of memory address
460 0, 0, 0, 0, // replaced with address of .got + 4
461 0xff, 0x25, // jmp indirect
462 0, 0, 0, 0, // replaced with address of .got + 8
466 // The first entry in the PLT for a shared object.
468 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
470 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
471 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
475 // Subsequent entries in the PLT for an executable.
477 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
479 0xff, 0x25, // jmp indirect
480 0, 0, 0, 0, // replaced with address of symbol in .got
481 0x68, // pushl immediate
482 0, 0, 0, 0, // replaced with offset into relocation table
483 0xe9, // jmp relative
484 0, 0, 0, 0 // replaced with offset to start of .plt
487 // Subsequent entries in the PLT for a shared object.
489 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
491 0xff, 0xa3, // jmp *offset(%ebx)
492 0, 0, 0, 0, // replaced with offset of symbol in .got
493 0x68, // pushl immediate
494 0, 0, 0, 0, // replaced with offset into relocation table
495 0xe9, // jmp relative
496 0, 0, 0, 0 // replaced with offset to start of .plt
499 // Write out the PLT. This uses the hand-coded instructions above,
500 // and adjusts them as needed. This is all specified by the i386 ELF
501 // Processor Supplement.
504 Output_data_plt_i386::do_write(Output_file* of)
506 const off_t offset = this->offset();
507 const off_t oview_size = this->data_size();
508 unsigned char* const oview = of->get_output_view(offset, oview_size);
510 const off_t got_file_offset = this->got_plt_->offset();
511 const off_t got_size = this->got_plt_->data_size();
512 unsigned char* const got_view = of->get_output_view(got_file_offset,
515 unsigned char* pov = oview;
517 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
518 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
520 if (parameters->output_is_shared())
521 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
524 memcpy(pov, exec_first_plt_entry, plt_entry_size);
525 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
526 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
528 pov += plt_entry_size;
530 unsigned char* got_pov = got_view;
532 memset(got_pov, 0, 12);
535 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
537 unsigned int plt_offset = plt_entry_size;
538 unsigned int plt_rel_offset = 0;
539 unsigned int got_offset = 12;
540 const unsigned int count = this->count_;
541 for (unsigned int i = 0;
544 pov += plt_entry_size,
546 plt_offset += plt_entry_size,
547 plt_rel_offset += rel_size,
550 // Set and adjust the PLT entry itself.
552 if (parameters->output_is_shared())
554 memcpy(pov, dyn_plt_entry, plt_entry_size);
555 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
559 memcpy(pov, exec_plt_entry, plt_entry_size);
560 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
565 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
566 elfcpp::Swap<32, false>::writeval(pov + 12,
567 - (plt_offset + plt_entry_size));
569 // Set the entry in the GOT.
570 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
573 gold_assert(pov - oview == oview_size);
574 gold_assert(got_pov - got_view == got_size);
576 of->write_output_view(offset, oview_size, oview);
577 of->write_output_view(got_file_offset, got_size, got_view);
580 // Create a PLT entry for a global symbol.
583 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
585 if (gsym->has_plt_offset())
588 if (this->plt_ == NULL)
590 // Create the GOT sections first.
591 this->got_section(symtab, layout);
593 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
594 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
596 | elfcpp::SHF_EXECINSTR),
600 this->plt_->add_entry(gsym);
603 // Handle a relocation against a non-function symbol defined in a
604 // dynamic object. The traditional way to handle this is to generate
605 // a COPY relocation to copy the variable at runtime from the shared
606 // object into the executable's data segment. However, this is
607 // undesirable in general, as if the size of the object changes in the
608 // dynamic object, the executable will no longer work correctly. If
609 // this relocation is in a writable section, then we can create a
610 // dynamic reloc and the dynamic linker will resolve it to the correct
611 // address at runtime. However, we do not want do that if the
612 // relocation is in a read-only section, as it would prevent the
613 // readonly segment from being shared. And if we have to eventually
614 // generate a COPY reloc, then any dynamic relocations will be
615 // useless. So this means that if this is a writable section, we need
616 // to save the relocation until we see whether we have to create a
617 // COPY relocation for this symbol for any other relocation.
620 Target_i386::copy_reloc(const General_options* options,
621 Symbol_table* symtab,
623 Sized_relobj<32, false>* object,
624 unsigned int data_shndx, Symbol* gsym,
625 const elfcpp::Rel<32, false>& rel)
627 Sized_symbol<32>* ssym;
628 ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
631 if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
634 // So far we do not need a COPY reloc. Save this relocation.
635 // If it turns out that we never need a COPY reloc for this
636 // symbol, then we will emit the relocation.
637 if (this->copy_relocs_ == NULL)
638 this->copy_relocs_ = new Copy_relocs<32, false>();
639 this->copy_relocs_->save(ssym, object, data_shndx, rel);
643 // Allocate space for this symbol in the .bss section.
645 elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
647 // There is no defined way to determine the required alignment
648 // of the symbol. We pick the alignment based on the size. We
649 // set an arbitrary maximum of 256.
651 for (align = 1; align < 512; align <<= 1)
652 if ((symsize & align) != 0)
655 if (this->dynbss_ == NULL)
657 this->dynbss_ = new Output_data_space(align);
658 layout->add_output_section_data(".bss",
661 | elfcpp::SHF_WRITE),
665 Output_data_space* dynbss = this->dynbss_;
667 if (align > dynbss->addralign())
668 dynbss->set_space_alignment(align);
670 off_t dynbss_size = dynbss->data_size();
671 dynbss_size = align_address(dynbss_size, align);
672 off_t offset = dynbss_size;
673 dynbss->set_space_size(dynbss_size + symsize);
675 symtab->define_with_copy_reloc(this, ssym, dynbss, offset);
677 // Add the COPY reloc.
678 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
679 rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
683 // Optimize the TLS relocation type based on what we know about the
684 // symbol. IS_FINAL is true if the final address of this symbol is
685 // known at link time.
687 tls::Tls_optimization
688 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
690 // If we are generating a shared library, then we can't do anything
692 if (parameters->output_is_shared())
693 return tls::TLSOPT_NONE;
697 case elfcpp::R_386_TLS_GD:
698 case elfcpp::R_386_TLS_GOTDESC:
699 case elfcpp::R_386_TLS_DESC_CALL:
700 // These are General-Dynamic which permits fully general TLS
701 // access. Since we know that we are generating an executable,
702 // we can convert this to Initial-Exec. If we also know that
703 // this is a local symbol, we can further switch to Local-Exec.
705 return tls::TLSOPT_TO_LE;
706 return tls::TLSOPT_TO_IE;
708 case elfcpp::R_386_TLS_LDM:
709 // This is Local-Dynamic, which refers to a local symbol in the
710 // dynamic TLS block. Since we know that we generating an
711 // executable, we can switch to Local-Exec.
712 return tls::TLSOPT_TO_LE;
714 case elfcpp::R_386_TLS_LDO_32:
715 // Another type of Local-Dynamic relocation.
716 return tls::TLSOPT_TO_LE;
718 case elfcpp::R_386_TLS_IE:
719 case elfcpp::R_386_TLS_GOTIE:
720 case elfcpp::R_386_TLS_IE_32:
721 // These are Initial-Exec relocs which get the thread offset
722 // from the GOT. If we know that we are linking against the
723 // local symbol, we can switch to Local-Exec, which links the
724 // thread offset into the instruction.
726 return tls::TLSOPT_TO_LE;
727 return tls::TLSOPT_NONE;
729 case elfcpp::R_386_TLS_LE:
730 case elfcpp::R_386_TLS_LE_32:
731 // When we already have Local-Exec, there is nothing further we
733 return tls::TLSOPT_NONE;
740 // Report an unsupported relocation against a local symbol.
743 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
746 gold_error(_("%s: unsupported reloc %u against local symbol"),
747 object->name().c_str(), r_type);
750 // Scan a relocation for a local symbol.
753 Target_i386::Scan::local(const General_options&,
754 Symbol_table* symtab,
757 Sized_relobj<32, false>* object,
758 unsigned int data_shndx,
759 const elfcpp::Rel<32, false>& reloc,
761 const elfcpp::Sym<32, false>&)
765 case elfcpp::R_386_NONE:
766 case elfcpp::R_386_GNU_VTINHERIT:
767 case elfcpp::R_386_GNU_VTENTRY:
770 case elfcpp::R_386_32:
771 case elfcpp::R_386_16:
772 case elfcpp::R_386_8:
773 // If building a shared library (or a position-independent
774 // executable), we need to create a dynamic relocation for
775 // this location. The relocation applied at link time will
776 // apply the link-time value, so we flag the location with
777 // an R_386_RELATIVE relocation so the dynamic loader can
778 // relocate it easily.
779 if (parameters->output_is_position_independent())
781 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
782 if (r_type == elfcpp::R_386_32)
783 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, data_shndx,
784 reloc.get_r_offset());
787 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
788 rel_dyn->add_local(object, r_sym, r_type, data_shndx,
789 reloc.get_r_offset());
794 case elfcpp::R_386_PC32:
795 case elfcpp::R_386_PC16:
796 case elfcpp::R_386_PC8:
799 case elfcpp::R_386_PLT32:
800 // Since we know this is a local symbol, we can handle this as a
804 case elfcpp::R_386_GOTOFF:
805 case elfcpp::R_386_GOTPC:
806 // We need a GOT section.
807 target->got_section(symtab, layout);
810 case elfcpp::R_386_GOT32:
812 // The symbol requires a GOT entry.
813 Output_data_got<32, false>* got = target->got_section(symtab, layout);
814 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
815 if (got->add_local(object, r_sym))
817 // If we are generating a shared object, we need to add a
818 // dynamic RELATIVE relocation for this symbol.
819 if (parameters->output_is_position_independent())
821 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
822 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
823 data_shndx, reloc.get_r_offset());
829 // These are relocations which should only be seen by the
830 // dynamic linker, and should never be seen here.
831 case elfcpp::R_386_COPY:
832 case elfcpp::R_386_GLOB_DAT:
833 case elfcpp::R_386_JUMP_SLOT:
834 case elfcpp::R_386_RELATIVE:
835 case elfcpp::R_386_TLS_TPOFF:
836 case elfcpp::R_386_TLS_DTPMOD32:
837 case elfcpp::R_386_TLS_DTPOFF32:
838 case elfcpp::R_386_TLS_TPOFF32:
839 case elfcpp::R_386_TLS_DESC:
840 gold_error(_("%s: unexpected reloc %u in object file"),
841 object->name().c_str(), r_type);
844 // These are initial TLS relocs, which are expected when
846 case elfcpp::R_386_TLS_GD: // Global-dynamic
847 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
848 case elfcpp::R_386_TLS_DESC_CALL:
849 case elfcpp::R_386_TLS_LDM: // Local-dynamic
850 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
851 case elfcpp::R_386_TLS_IE: // Initial-exec
852 case elfcpp::R_386_TLS_IE_32:
853 case elfcpp::R_386_TLS_GOTIE:
854 case elfcpp::R_386_TLS_LE: // Local-exec
855 case elfcpp::R_386_TLS_LE_32:
857 bool output_is_shared = parameters->output_is_shared();
858 const tls::Tls_optimization optimized_type
859 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
862 case elfcpp::R_386_TLS_GD: // Global-dynamic
863 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
864 case elfcpp::R_386_TLS_DESC_CALL:
865 // FIXME: If not relaxing to LE, we need to generate
866 // DTPMOD32 and DTPOFF32 relocs.
867 if (optimized_type != tls::TLSOPT_TO_LE)
868 unsupported_reloc_local(object, r_type);
871 case elfcpp::R_386_TLS_LDM: // Local-dynamic
872 // FIXME: If not relaxing to LE, we need to generate a
874 if (optimized_type != tls::TLSOPT_TO_LE)
875 unsupported_reloc_local(object, r_type);
878 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
881 case elfcpp::R_386_TLS_IE: // Initial-exec
882 case elfcpp::R_386_TLS_IE_32:
883 case elfcpp::R_386_TLS_GOTIE:
884 // FIXME: If not relaxing to LE, we need to generate a
885 // TPOFF or TPOFF32 reloc.
886 if (optimized_type != tls::TLSOPT_TO_LE)
887 unsupported_reloc_local(object, r_type);
890 case elfcpp::R_386_TLS_LE: // Local-exec
891 case elfcpp::R_386_TLS_LE_32:
892 // FIXME: If generating a shared object, we need to copy
893 // this relocation into the object.
894 gold_assert(!output_is_shared);
903 case elfcpp::R_386_32PLT:
904 case elfcpp::R_386_TLS_GD_32:
905 case elfcpp::R_386_TLS_GD_PUSH:
906 case elfcpp::R_386_TLS_GD_CALL:
907 case elfcpp::R_386_TLS_GD_POP:
908 case elfcpp::R_386_TLS_LDM_32:
909 case elfcpp::R_386_TLS_LDM_PUSH:
910 case elfcpp::R_386_TLS_LDM_CALL:
911 case elfcpp::R_386_TLS_LDM_POP:
912 case elfcpp::R_386_USED_BY_INTEL_200:
914 unsupported_reloc_local(object, r_type);
919 // Report an unsupported relocation against a global symbol.
922 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
926 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
927 object->name().c_str(), r_type, gsym->name());
930 // Scan a relocation for a global symbol.
933 Target_i386::Scan::global(const General_options& options,
934 Symbol_table* symtab,
937 Sized_relobj<32, false>* object,
938 unsigned int data_shndx,
939 const elfcpp::Rel<32, false>& reloc,
945 case elfcpp::R_386_NONE:
946 case elfcpp::R_386_GNU_VTINHERIT:
947 case elfcpp::R_386_GNU_VTENTRY:
950 case elfcpp::R_386_32:
951 case elfcpp::R_386_PC32:
952 case elfcpp::R_386_16:
953 case elfcpp::R_386_PC16:
954 case elfcpp::R_386_8:
955 case elfcpp::R_386_PC8:
957 bool is_pcrel = (r_type == elfcpp::R_386_PC32
958 || r_type == elfcpp::R_386_PC16
959 || r_type == elfcpp::R_386_PC8);
961 if (gsym->is_from_dynobj()
962 || (parameters->output_is_shared()
963 && gsym->is_preemptible()))
965 // (a) This symbol is defined in a dynamic object. If it is a
966 // function, we make a PLT entry. Otherwise we need to
967 // either generate a COPY reloc or copy this reloc.
968 // (b) We are building a shared object and this symbol is
969 // preemptible. If it is a function, we make a PLT entry.
970 // Otherwise, we copy the reloc.
971 if (gsym->type() == elfcpp::STT_FUNC)
973 target->make_plt_entry(symtab, layout, gsym);
975 // If this is not a PC relative reference, then we may
976 // be taking the address of the function. In that case
977 // we need to set the entry in the dynamic symbol table
978 // to the address of the PLT entry. We will also need to
979 // create a dynamic relocation.
982 if (gsym->is_from_dynobj())
983 gsym->set_needs_dynsym_value();
984 if (parameters->output_is_position_independent())
986 Reloc_section* rel_dyn =
987 target->rel_dyn_section(layout);
988 rel_dyn->add_global(gsym, r_type, object, data_shndx,
989 reloc.get_r_offset());
993 else if (parameters->output_is_shared())
995 // We do not make COPY relocs in shared objects.
996 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
997 rel_dyn->add_global(gsym, r_type, object, data_shndx,
998 reloc.get_r_offset());
1001 target->copy_reloc(&options, symtab, layout, object, data_shndx,
1004 else if (!is_pcrel && parameters->output_is_position_independent())
1006 // This is not a PC-relative reference, so we need to generate
1007 // a dynamic relocation. At this point, we know the symbol
1008 // is not preemptible, so we can use the RELATIVE relocation.
1009 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1010 if (r_type == elfcpp::R_386_32)
1011 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, data_shndx,
1012 reloc.get_r_offset());
1014 rel_dyn->add_global(gsym, r_type, object, data_shndx,
1015 reloc.get_r_offset());
1020 case elfcpp::R_386_GOT32:
1022 // The symbol requires a GOT entry.
1023 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1024 if (got->add_global(gsym))
1026 // If this symbol is not fully resolved, we need to add a
1027 // dynamic relocation for it.
1028 if (!gsym->final_value_is_known())
1030 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1031 rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
1032 gsym->got_offset());
1038 case elfcpp::R_386_PLT32:
1039 // If the symbol is fully resolved, this is just a PC32 reloc.
1040 // Otherwise we need a PLT entry.
1041 if (gsym->final_value_is_known())
1043 // If building a shared library, we can also skip the PLT entry
1044 // if the symbol is defined in the output file and is protected
1046 if (gsym->is_defined()
1047 && !gsym->is_from_dynobj()
1048 && !gsym->is_preemptible())
1050 target->make_plt_entry(symtab, layout, gsym);
1053 case elfcpp::R_386_GOTOFF:
1054 case elfcpp::R_386_GOTPC:
1055 // We need a GOT section.
1056 target->got_section(symtab, layout);
1059 // These are relocations which should only be seen by the
1060 // dynamic linker, and should never be seen here.
1061 case elfcpp::R_386_COPY:
1062 case elfcpp::R_386_GLOB_DAT:
1063 case elfcpp::R_386_JUMP_SLOT:
1064 case elfcpp::R_386_RELATIVE:
1065 case elfcpp::R_386_TLS_TPOFF:
1066 case elfcpp::R_386_TLS_DTPMOD32:
1067 case elfcpp::R_386_TLS_DTPOFF32:
1068 case elfcpp::R_386_TLS_TPOFF32:
1069 case elfcpp::R_386_TLS_DESC:
1070 gold_error(_("%s: unexpected reloc %u in object file"),
1071 object->name().c_str(), r_type);
1074 // These are initial tls relocs, which are expected when
1076 case elfcpp::R_386_TLS_GD: // Global-dynamic
1077 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1078 case elfcpp::R_386_TLS_DESC_CALL:
1079 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1080 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1081 case elfcpp::R_386_TLS_IE: // Initial-exec
1082 case elfcpp::R_386_TLS_IE_32:
1083 case elfcpp::R_386_TLS_GOTIE:
1084 case elfcpp::R_386_TLS_LE: // Local-exec
1085 case elfcpp::R_386_TLS_LE_32:
1087 const bool is_final = gsym->final_value_is_known();
1088 const tls::Tls_optimization optimized_type
1089 = Target_i386::optimize_tls_reloc(is_final, r_type);
1092 case elfcpp::R_386_TLS_GD: // Global-dynamic
1093 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1094 case elfcpp::R_386_TLS_DESC_CALL:
1095 // FIXME: If not relaxing to LE, we need to generate
1096 // DTPMOD32 and DTPOFF32 relocs.
1097 if (optimized_type != tls::TLSOPT_TO_LE)
1098 unsupported_reloc_global(object, r_type, gsym);
1101 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1102 // FIXME: If not relaxing to LE, we need to generate a
1104 if (optimized_type != tls::TLSOPT_TO_LE)
1105 unsupported_reloc_global(object, r_type, gsym);
1108 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1111 case elfcpp::R_386_TLS_IE: // Initial-exec
1112 case elfcpp::R_386_TLS_IE_32:
1113 case elfcpp::R_386_TLS_GOTIE:
1114 // FIXME: If not relaxing to LE, we need to generate a
1115 // TPOFF or TPOFF32 reloc.
1116 if (optimized_type != tls::TLSOPT_TO_LE)
1117 unsupported_reloc_global(object, r_type, gsym);
1120 case elfcpp::R_386_TLS_LE: // Local-exec
1121 case elfcpp::R_386_TLS_LE_32:
1122 // FIXME: If generating a shared object, we need to copy
1123 // this relocation into the object.
1124 gold_assert(!parameters->output_is_shared());
1133 case elfcpp::R_386_32PLT:
1134 case elfcpp::R_386_TLS_GD_32:
1135 case elfcpp::R_386_TLS_GD_PUSH:
1136 case elfcpp::R_386_TLS_GD_CALL:
1137 case elfcpp::R_386_TLS_GD_POP:
1138 case elfcpp::R_386_TLS_LDM_32:
1139 case elfcpp::R_386_TLS_LDM_PUSH:
1140 case elfcpp::R_386_TLS_LDM_CALL:
1141 case elfcpp::R_386_TLS_LDM_POP:
1142 case elfcpp::R_386_USED_BY_INTEL_200:
1144 unsupported_reloc_global(object, r_type, gsym);
1149 // Scan relocations for a section.
1152 Target_i386::scan_relocs(const General_options& options,
1153 Symbol_table* symtab,
1155 Sized_relobj<32, false>* object,
1156 unsigned int data_shndx,
1157 unsigned int sh_type,
1158 const unsigned char* prelocs,
1160 size_t local_symbol_count,
1161 const unsigned char* plocal_symbols,
1162 Symbol** global_symbols)
1164 if (sh_type == elfcpp::SHT_RELA)
1166 gold_error(_("%s: unsupported RELA reloc section"),
1167 object->name().c_str());
1171 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1186 // Finalize the sections.
1189 Target_i386::do_finalize_sections(Layout* layout)
1191 // Fill in some more dynamic tags.
1192 Output_data_dynamic* const odyn = layout->dynamic_data();
1195 if (this->got_plt_ != NULL)
1196 odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1198 if (this->plt_ != NULL)
1200 const Output_data* od = this->plt_->rel_plt();
1201 odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1202 odyn->add_section_address(elfcpp::DT_JMPREL, od);
1203 odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1206 if (this->rel_dyn_ != NULL)
1208 const Output_data* od = this->rel_dyn_;
1209 odyn->add_section_address(elfcpp::DT_REL, od);
1210 odyn->add_section_size(elfcpp::DT_RELSZ, od);
1211 odyn->add_constant(elfcpp::DT_RELENT,
1212 elfcpp::Elf_sizes<32>::rel_size);
1215 if (!parameters->output_is_shared())
1217 // The value of the DT_DEBUG tag is filled in by the dynamic
1218 // linker at run time, and used by the debugger.
1219 odyn->add_constant(elfcpp::DT_DEBUG, 0);
1223 // Emit any relocs we saved in an attempt to avoid generating COPY
1225 if (this->copy_relocs_ == NULL)
1227 if (this->copy_relocs_->any_to_emit())
1229 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1230 this->copy_relocs_->emit(rel_dyn);
1232 delete this->copy_relocs_;
1233 this->copy_relocs_ = NULL;
1236 // Return whether a direct absolute static relocation needs to be applied.
1237 // In cases where Scan::local() or Scan::global() has created
1238 // a dynamic relocation other than R_386_RELATIVE, the addend
1239 // of the relocation is carried in the data, and we must not
1240 // apply the static relocation.
1243 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1247 // For local symbols, return FALSE if a non-RELATIVE dynamic
1248 // relocation was created; return TRUE otherwise.
1250 return (!parameters->output_is_position_independent() || is_32bit);
1252 // For global symbols, mimic the logic in Scan::global()
1253 // to decide whether a non-RELATIVE dynamic relocation was
1255 // FIXME: This is ugly. Try to refactor this logic so it can be
1256 // shared by Scan::global() and Relocate::relocate().
1257 if (gsym->is_from_dynobj()
1258 || (parameters->output_is_shared()
1259 && gsym->is_preemptible()))
1261 if (gsym->type() == elfcpp::STT_FUNC)
1263 if (!is_pcrel && parameters->output_is_position_independent())
1269 else if (!is_pcrel && parameters->output_is_position_independent())
1272 // For all other cases, return TRUE
1276 // Perform a relocation.
1279 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1280 Target_i386* target,
1282 const elfcpp::Rel<32, false>& rel,
1283 unsigned int r_type,
1284 const Sized_symbol<32>* gsym,
1285 const Symbol_value<32>* psymval,
1286 unsigned char* view,
1287 elfcpp::Elf_types<32>::Elf_Addr address,
1290 if (this->skip_call_tls_get_addr_)
1292 if (r_type != elfcpp::R_386_PLT32
1294 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1295 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1296 _("missing expected TLS relocation"));
1299 this->skip_call_tls_get_addr_ = false;
1304 // Pick the value to use for symbols defined in shared objects.
1305 Symbol_value<32> symval;
1307 && (gsym->is_from_dynobj()
1308 || (parameters->output_is_shared()
1309 && gsym->is_preemptible()))
1310 && gsym->has_plt_offset())
1312 symval.set_output_value(target->plt_section()->address()
1313 + gsym->plt_offset());
1317 const Sized_relobj<32, false>* object = relinfo->object;
1319 // Get the GOT offset if needed.
1320 // The GOT pointer points to the end of the GOT section.
1321 // We need to subtract the size of the GOT section to get
1322 // the actual offset to use in the relocation.
1323 bool have_got_offset = false;
1324 unsigned int got_offset = 0;
1327 case elfcpp::R_386_GOT32:
1330 gold_assert(gsym->has_got_offset());
1331 got_offset = gsym->got_offset() - target->got_size();
1335 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1336 got_offset = object->local_got_offset(r_sym) - target->got_size();
1338 have_got_offset = true;
1347 case elfcpp::R_386_NONE:
1348 case elfcpp::R_386_GNU_VTINHERIT:
1349 case elfcpp::R_386_GNU_VTENTRY:
1352 case elfcpp::R_386_32:
1353 if (should_apply_static_reloc(gsym, false, true))
1354 Relocate_functions<32, false>::rel32(view, object, psymval);
1357 case elfcpp::R_386_PC32:
1358 if (should_apply_static_reloc(gsym, true, true))
1359 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1362 case elfcpp::R_386_16:
1363 if (should_apply_static_reloc(gsym, false, false))
1364 Relocate_functions<32, false>::rel16(view, object, psymval);
1367 case elfcpp::R_386_PC16:
1368 if (should_apply_static_reloc(gsym, true, false))
1369 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1372 case elfcpp::R_386_8:
1373 if (should_apply_static_reloc(gsym, false, false))
1374 Relocate_functions<32, false>::rel8(view, object, psymval);
1377 case elfcpp::R_386_PC8:
1378 if (should_apply_static_reloc(gsym, true, false))
1379 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1382 case elfcpp::R_386_PLT32:
1383 gold_assert(gsym == NULL
1384 || gsym->has_plt_offset()
1385 || gsym->final_value_is_known());
1386 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1389 case elfcpp::R_386_GOT32:
1390 gold_assert(have_got_offset);
1391 Relocate_functions<32, false>::rel32(view, got_offset);
1394 case elfcpp::R_386_GOTOFF:
1396 elfcpp::Elf_types<32>::Elf_Addr value;
1397 value = (psymval->value(object, 0)
1398 - target->got_plt_section()->address());
1399 Relocate_functions<32, false>::rel32(view, value);
1403 case elfcpp::R_386_GOTPC:
1405 elfcpp::Elf_types<32>::Elf_Addr value;
1406 value = target->got_plt_section()->address();
1407 Relocate_functions<32, false>::pcrel32(view, value, address);
1411 case elfcpp::R_386_COPY:
1412 case elfcpp::R_386_GLOB_DAT:
1413 case elfcpp::R_386_JUMP_SLOT:
1414 case elfcpp::R_386_RELATIVE:
1415 // These are outstanding tls relocs, which are unexpected when
1417 case elfcpp::R_386_TLS_TPOFF:
1418 case elfcpp::R_386_TLS_DTPMOD32:
1419 case elfcpp::R_386_TLS_DTPOFF32:
1420 case elfcpp::R_386_TLS_TPOFF32:
1421 case elfcpp::R_386_TLS_DESC:
1422 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1423 _("unexpected reloc %u in object file"),
1427 // These are initial tls relocs, which are expected when
1429 case elfcpp::R_386_TLS_GD: // Global-dynamic
1430 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1431 case elfcpp::R_386_TLS_DESC_CALL:
1432 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1433 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1434 case elfcpp::R_386_TLS_IE: // Initial-exec
1435 case elfcpp::R_386_TLS_IE_32:
1436 case elfcpp::R_386_TLS_GOTIE:
1437 case elfcpp::R_386_TLS_LE: // Local-exec
1438 case elfcpp::R_386_TLS_LE_32:
1439 this->relocate_tls(relinfo, relnum, rel, r_type, gsym, psymval, view,
1440 address, view_size);
1443 case elfcpp::R_386_32PLT:
1444 case elfcpp::R_386_TLS_GD_32:
1445 case elfcpp::R_386_TLS_GD_PUSH:
1446 case elfcpp::R_386_TLS_GD_CALL:
1447 case elfcpp::R_386_TLS_GD_POP:
1448 case elfcpp::R_386_TLS_LDM_32:
1449 case elfcpp::R_386_TLS_LDM_PUSH:
1450 case elfcpp::R_386_TLS_LDM_CALL:
1451 case elfcpp::R_386_TLS_LDM_POP:
1452 case elfcpp::R_386_USED_BY_INTEL_200:
1454 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1455 _("unsupported reloc %u"),
1463 // Perform a TLS relocation.
1466 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1468 const elfcpp::Rel<32, false>& rel,
1469 unsigned int r_type,
1470 const Sized_symbol<32>* gsym,
1471 const Symbol_value<32>* psymval,
1472 unsigned char* view,
1473 elfcpp::Elf_types<32>::Elf_Addr,
1476 Output_segment* tls_segment = relinfo->layout->tls_segment();
1477 if (tls_segment == NULL)
1479 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1480 _("TLS reloc but no TLS segment"));
1484 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(relinfo->object, 0);
1486 const bool is_final = (gsym == NULL
1487 ? !parameters->output_is_position_independent()
1488 : gsym->final_value_is_known());
1489 const tls::Tls_optimization optimized_type
1490 = Target_i386::optimize_tls_reloc(is_final, r_type);
1493 case elfcpp::R_386_TLS_GD: // Global-dynamic
1494 if (optimized_type == tls::TLSOPT_TO_LE)
1496 this->tls_gd_to_le(relinfo, relnum, tls_segment,
1497 rel, r_type, value, view,
1501 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1502 _("unsupported reloc %u"),
1506 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1507 case elfcpp::R_386_TLS_DESC_CALL:
1508 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1509 _("unsupported reloc %u"),
1513 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1514 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1516 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1517 _("both SUN and GNU model "
1518 "TLS relocations"));
1521 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1522 if (optimized_type == tls::TLSOPT_TO_LE)
1524 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1525 value, view, view_size);
1528 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1529 _("unsupported reloc %u"),
1533 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1534 // This reloc can appear in debugging sections, in which case we
1535 // won't see the TLS_LDM reloc. The local_dynamic_type field
1537 if (optimized_type != tls::TLSOPT_TO_LE
1538 || this->local_dynamic_type_ == LOCAL_DYNAMIC_NONE)
1539 value = value - tls_segment->vaddr();
1540 else if (this->local_dynamic_type_ == LOCAL_DYNAMIC_GNU)
1541 value = value - (tls_segment->vaddr() + tls_segment->memsz());
1543 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1544 Relocate_functions<32, false>::rel32(view, value);
1547 case elfcpp::R_386_TLS_IE: // Initial-exec
1548 case elfcpp::R_386_TLS_GOTIE:
1549 case elfcpp::R_386_TLS_IE_32:
1550 if (optimized_type == tls::TLSOPT_TO_LE)
1552 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1553 rel, r_type, value, view,
1557 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1558 _("unsupported reloc %u"),
1562 case elfcpp::R_386_TLS_LE: // Local-exec
1563 value = value - (tls_segment->vaddr() + tls_segment->memsz());
1564 Relocate_functions<32, false>::rel32(view, value);
1567 case elfcpp::R_386_TLS_LE_32:
1568 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1569 Relocate_functions<32, false>::rel32(view, value);
1574 // Do a relocation in which we convert a TLS General-Dynamic to a
1578 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1580 Output_segment* tls_segment,
1581 const elfcpp::Rel<32, false>& rel,
1583 elfcpp::Elf_types<32>::Elf_Addr value,
1584 unsigned char* view,
1587 // leal foo(,%reg,1),%eax; call ___tls_get_addr
1588 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1589 // leal foo(%reg),%eax; call ___tls_get_addr
1590 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1592 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1593 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1595 unsigned char op1 = view[-1];
1596 unsigned char op2 = view[-2];
1598 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1599 op2 == 0x8d || op2 == 0x04);
1600 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1606 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1607 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1608 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1609 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1610 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1614 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1615 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1616 if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1619 // There is a trailing nop. Use the size byte subl.
1620 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1625 // Use the five byte subl.
1626 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1630 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1631 Relocate_functions<32, false>::rel32(view + roff, value);
1633 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1635 this->skip_call_tls_get_addr_ = true;
1638 // Do a relocation in which we convert a TLS Local-Dynamic to a
1642 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
1645 const elfcpp::Rel<32, false>& rel,
1647 elfcpp::Elf_types<32>::Elf_Addr,
1648 unsigned char* view,
1651 // leal foo(%reg), %eax; call ___tls_get_addr
1652 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1654 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1655 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1657 // FIXME: Does this test really always pass?
1658 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1659 view[-2] == 0x8d && view[-1] == 0x83);
1661 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1663 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1665 // The next reloc should be a PLT32 reloc against __tls_get_addr.
1667 this->skip_call_tls_get_addr_ = true;
1670 // Do a relocation in which we convert a TLS Initial-Exec to a
1674 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1676 Output_segment* tls_segment,
1677 const elfcpp::Rel<32, false>& rel,
1678 unsigned int r_type,
1679 elfcpp::Elf_types<32>::Elf_Addr value,
1680 unsigned char* view,
1683 // We have to actually change the instructions, which means that we
1684 // need to examine the opcodes to figure out which instruction we
1686 if (r_type == elfcpp::R_386_TLS_IE)
1688 // movl %gs:XX,%eax ==> movl $YY,%eax
1689 // movl %gs:XX,%reg ==> movl $YY,%reg
1690 // addl %gs:XX,%reg ==> addl $YY,%reg
1691 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
1692 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1694 unsigned char op1 = view[-1];
1697 // movl XX,%eax ==> movl $YY,%eax
1702 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1704 unsigned char op2 = view[-2];
1707 // movl XX,%reg ==> movl $YY,%reg
1708 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1709 (op1 & 0xc7) == 0x05);
1711 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1713 else if (op2 == 0x03)
1715 // addl XX,%reg ==> addl $YY,%reg
1716 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1717 (op1 & 0xc7) == 0x05);
1719 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1722 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
1727 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1728 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1729 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1730 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1731 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1733 unsigned char op1 = view[-1];
1734 unsigned char op2 = view[-2];
1735 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1736 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
1739 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
1741 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1743 else if (op2 == 0x2b)
1745 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
1747 view[-1] = 0xe8 | ((op1 >> 3) & 7);
1749 else if (op2 == 0x03)
1751 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
1753 view[-1] = 0xc0 | ((op1 >> 3) & 7);
1756 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
1759 value = tls_segment->vaddr() + tls_segment->memsz() - value;
1760 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
1763 Relocate_functions<32, false>::rel32(view, value);
1766 // Relocate section data.
1769 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
1770 unsigned int sh_type,
1771 const unsigned char* prelocs,
1773 unsigned char* view,
1774 elfcpp::Elf_types<32>::Elf_Addr address,
1777 gold_assert(sh_type == elfcpp::SHT_REL);
1779 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
1780 Target_i386::Relocate>(
1790 // Return the value to use for a dynamic which requires special
1791 // treatment. This is how we support equality comparisons of function
1792 // pointers across shared library boundaries, as described in the
1793 // processor specific ABI supplement.
1796 Target_i386::do_dynsym_value(const Symbol* gsym) const
1798 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
1799 return this->plt_section()->address() + gsym->plt_offset();
1802 // Return a string used to fill a code section with nops to take up
1803 // the specified length.
1806 Target_i386::do_code_fill(off_t length)
1810 // Build a jmp instruction to skip over the bytes.
1811 unsigned char jmp[5];
1813 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
1814 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1815 + std::string(length - 5, '\0'));
1818 // Nop sequences of various lengths.
1819 const char nop1[1] = { 0x90 }; // nop
1820 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
1821 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
1822 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
1823 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
1824 0x00 }; // leal 0(%esi,1),%esi
1825 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1827 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1829 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
1830 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1831 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
1832 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
1834 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1835 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1837 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1838 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1840 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1841 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1842 0x00, 0x00, 0x00, 0x00 };
1843 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1844 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1845 0x27, 0x00, 0x00, 0x00,
1847 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1848 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1849 0xbc, 0x27, 0x00, 0x00,
1851 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1852 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1853 0x90, 0x90, 0x90, 0x90,
1856 const char* nops[16] = {
1858 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
1859 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
1862 return std::string(nops[length], length);
1865 // The selector for i386 object files.
1867 class Target_selector_i386 : public Target_selector
1870 Target_selector_i386()
1871 : Target_selector(elfcpp::EM_386, 32, false)
1875 recognize(int machine, int osabi, int abiversion);
1878 Target_i386* target_;
1881 // Recognize an i386 object file when we already know that the machine
1882 // number is EM_386.
1885 Target_selector_i386::recognize(int, int, int)
1887 if (this->target_ == NULL)
1888 this->target_ = new Target_i386();
1889 return this->target_;
1892 Target_selector_i386 target_selector_i386;
1894 } // End anonymous namespace.