1 // target-reloc.h -- target specific relocation support -*- C++ -*-
3 // Copyright (C) 2006-2018 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 #ifndef GOLD_TARGET_RELOC_H
24 #define GOLD_TARGET_RELOC_H
30 #include "reloc-types.h"
35 // This function implements the generic part of reloc scanning. The
36 // template parameter Scan must be a class type which provides two
37 // functions: local() and global(). Those functions implement the
38 // machine specific part of scanning. We do it this way to
39 // avoid making a function call for each relocation, and to avoid
40 // repeating the generic code for each target.
42 template<int size
, bool big_endian
, typename Target_type
,
43 typename Scan
, typename Classify_reloc
>
49 Sized_relobj_file
<size
, big_endian
>* object
,
50 unsigned int data_shndx
,
51 const unsigned char* prelocs
,
53 Output_section
* output_section
,
54 bool needs_special_offset_handling
,
56 const unsigned char* plocal_syms
)
58 typedef typename
Classify_reloc::Reltype Reltype
;
59 const int reloc_size
= Classify_reloc::reloc_size
;
60 const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
63 for (size_t i
= 0; i
< reloc_count
; ++i
, prelocs
+= reloc_size
)
65 Reltype
reloc(prelocs
);
67 if (needs_special_offset_handling
68 && !output_section
->is_input_address_mapped(object
, data_shndx
,
69 reloc
.get_r_offset()))
72 unsigned int r_sym
= Classify_reloc::get_r_sym(&reloc
);
73 unsigned int r_type
= Classify_reloc::get_r_type(&reloc
);
75 if (r_sym
< local_count
)
77 gold_assert(plocal_syms
!= NULL
);
78 typename
elfcpp::Sym
<size
, big_endian
> lsym(plocal_syms
80 unsigned int shndx
= lsym
.get_st_shndx();
82 shndx
= object
->adjust_sym_shndx(r_sym
, shndx
, &is_ordinary
);
83 // If RELOC is a relocation against a local symbol in a
84 // section we are discarding then we can ignore it. It will
85 // eventually become a reloc against the value zero.
87 // FIXME: We should issue a warning if this is an
88 // allocated section; is this the best place to do it?
90 // FIXME: The old GNU linker would in some cases look
91 // for the linkonce section which caused this section to
92 // be discarded, and, if the other section was the same
93 // size, change the reloc to refer to the other section.
94 // That seems risky and weird to me, and I don't know of
95 // any case where it is actually required.
96 bool is_discarded
= (is_ordinary
97 && shndx
!= elfcpp::SHN_UNDEF
98 && !object
->is_section_included(shndx
)
99 && !symtab
->is_section_folded(object
, shndx
));
100 scan
.local(symtab
, layout
, target
, object
, data_shndx
,
101 output_section
, reloc
, r_type
, lsym
, is_discarded
);
105 Symbol
* gsym
= object
->global_symbol(r_sym
);
106 gold_assert(gsym
!= NULL
);
107 if (gsym
->is_forwarder())
108 gsym
= symtab
->resolve_forwards(gsym
);
110 scan
.global(symtab
, layout
, target
, object
, data_shndx
,
111 output_section
, reloc
, r_type
, gsym
);
116 // Behavior for relocations to discarded comdat sections.
120 CB_UNDETERMINED
, // Not yet determined -- need to look at section name.
121 CB_PRETEND
, // Attempt to map to the corresponding kept section.
122 CB_IGNORE
, // Ignore the relocation.
123 CB_WARNING
// Print a warning.
126 class Default_comdat_behavior
129 // Decide what the linker should do for relocations that refer to
130 // discarded comdat sections. This decision is based on the name of
131 // the section being relocated.
133 inline Comdat_behavior
134 get(const char* name
)
136 if (Layout::is_debug_info_section(name
))
138 if (strcmp(name
, ".eh_frame") == 0
139 || strcmp(name
, ".gcc_except_table") == 0)
145 // Give an error for a symbol with non-default visibility which is not
149 visibility_error(const Symbol
* sym
)
152 switch (sym
->visibility())
154 case elfcpp::STV_INTERNAL
:
157 case elfcpp::STV_HIDDEN
:
160 case elfcpp::STV_PROTECTED
:
166 gold_error(_("%s symbol '%s' is not defined locally"),
170 // Return true if we are should issue an error saying that SYM is an
171 // undefined symbol. This is called if there is a relocation against
175 issue_undefined_symbol_error(const Symbol
* sym
)
177 // We only report global symbols.
181 // We only report undefined symbols.
182 if (!sym
->is_undefined() && !sym
->is_placeholder())
185 // We don't report weak symbols.
186 if (sym
->is_weak_undefined())
189 // We don't report symbols defined in discarded sections,
190 // unless they're placeholder symbols that should have been
191 // provided by a plugin.
192 if (sym
->is_defined_in_discarded_section() && !sym
->is_placeholder())
195 // If the target defines this symbol, don't report it here.
196 if (parameters
->target().is_defined_by_abi(sym
))
199 // See if we've been told to ignore whether this symbol is
201 const char* const u
= parameters
->options().unresolved_symbols();
204 if (strcmp(u
, "ignore-all") == 0)
206 if (strcmp(u
, "report-all") == 0)
208 if (strcmp(u
, "ignore-in-object-files") == 0 && !sym
->in_dyn())
210 if (strcmp(u
, "ignore-in-shared-libs") == 0 && !sym
->in_reg())
214 // If the symbol is hidden, report it.
215 if (sym
->visibility() == elfcpp::STV_HIDDEN
)
218 // When creating a shared library, only report unresolved symbols if
220 if (parameters
->options().shared() && !parameters
->options().defs())
223 // Otherwise issue a warning.
227 // This function implements the generic part of relocation processing.
228 // The template parameter Relocate must be a class type which provides
229 // a single function, relocate(), which implements the machine
230 // specific part of a relocation.
232 // The template parameter Relocate_comdat_behavior is a class type
233 // which provides a single function, get(), which determines what the
234 // linker should do for relocations that refer to discarded comdat
237 // SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of
238 // the data. SH_TYPE is the section type: SHT_REL or SHT_RELA.
239 // RELOCATE implements operator() to do a relocation.
241 // PRELOCS points to the relocation data. RELOC_COUNT is the number
242 // of relocs. OUTPUT_SECTION is the output section.
243 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
244 // mapped to output offsets.
246 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
247 // VIEW_SIZE is the size. These refer to the input section, unless
248 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
249 // the output section.
251 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is
252 // not NULL, it is a vector indexed by relocation index. If that
253 // entry is not NULL, it points to a global symbol which used as the
254 // symbol for the relocation, ignoring the symbol index in the
257 template<int size
, bool big_endian
, typename Target_type
,
259 typename Relocate_comdat_behavior
,
260 typename Classify_reloc
>
263 const Relocate_info
<size
, big_endian
>* relinfo
,
265 const unsigned char* prelocs
,
267 Output_section
* output_section
,
268 bool needs_special_offset_handling
,
270 typename
elfcpp::Elf_types
<size
>::Elf_Addr view_address
,
271 section_size_type view_size
,
272 const Reloc_symbol_changes
* reloc_symbol_changes
)
274 typedef typename
Classify_reloc::Reltype Reltype
;
275 const int reloc_size
= Classify_reloc::reloc_size
;
277 Relocate_comdat_behavior relocate_comdat_behavior
;
279 Sized_relobj_file
<size
, big_endian
>* object
= relinfo
->object
;
280 unsigned int local_count
= object
->local_symbol_count();
282 Comdat_behavior comdat_behavior
= CB_UNDETERMINED
;
284 for (size_t i
= 0; i
< reloc_count
; ++i
, prelocs
+= reloc_size
)
286 Reltype
reloc(prelocs
);
288 section_offset_type offset
=
289 convert_to_section_size_type(reloc
.get_r_offset());
291 if (needs_special_offset_handling
)
293 offset
= output_section
->output_offset(relinfo
->object
,
300 unsigned int r_sym
= Classify_reloc::get_r_sym(&reloc
);
302 const Sized_symbol
<size
>* sym
;
304 Symbol_value
<size
> symval
;
305 const Symbol_value
<size
> *psymval
;
306 bool is_defined_in_discarded_section
;
308 const Symbol
* gsym
= NULL
;
309 if (r_sym
< local_count
310 && (reloc_symbol_changes
== NULL
311 || (*reloc_symbol_changes
)[i
] == NULL
))
314 psymval
= object
->local_symbol(r_sym
);
316 // If the local symbol belongs to a section we are discarding,
317 // and that section is a debug section, try to find the
318 // corresponding kept section and map this symbol to its
319 // counterpart in the kept section. The symbol must not
320 // correspond to a section we are folding.
322 shndx
= psymval
->input_shndx(&is_ordinary
);
323 is_defined_in_discarded_section
=
325 && shndx
!= elfcpp::SHN_UNDEF
326 && !object
->is_section_included(shndx
)
327 && !relinfo
->symtab
->is_section_folded(object
, shndx
));
331 if (reloc_symbol_changes
!= NULL
332 && (*reloc_symbol_changes
)[i
] != NULL
)
333 gsym
= (*reloc_symbol_changes
)[i
];
336 gsym
= object
->global_symbol(r_sym
);
337 gold_assert(gsym
!= NULL
);
338 if (gsym
->is_forwarder())
339 gsym
= relinfo
->symtab
->resolve_forwards(gsym
);
342 sym
= static_cast<const Sized_symbol
<size
>*>(gsym
);
343 if (sym
->has_symtab_index() && sym
->symtab_index() != -1U)
344 symval
.set_output_symtab_index(sym
->symtab_index());
346 symval
.set_no_output_symtab_entry();
347 symval
.set_output_value(sym
->value());
348 if (gsym
->type() == elfcpp::STT_TLS
)
349 symval
.set_is_tls_symbol();
350 else if (gsym
->type() == elfcpp::STT_GNU_IFUNC
)
351 symval
.set_is_ifunc_symbol();
354 is_defined_in_discarded_section
=
355 (gsym
->is_defined_in_discarded_section()
356 && gsym
->is_undefined());
360 Symbol_value
<size
> symval2
;
361 if (is_defined_in_discarded_section
)
363 if (comdat_behavior
== CB_UNDETERMINED
)
365 std::string name
= object
->section_name(relinfo
->data_shndx
);
366 comdat_behavior
= relocate_comdat_behavior
.get(name
.c_str());
368 if (comdat_behavior
== CB_PRETEND
)
370 // FIXME: This case does not work for global symbols.
371 // We have no place to store the original section index.
372 // Fortunately this does not matter for comdat sections,
373 // only for sections explicitly discarded by a linker
376 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
=
377 object
->map_to_kept_section(shndx
, &found
);
379 symval2
.set_output_value(value
+ psymval
->input_value());
381 symval2
.set_output_value(0);
385 if (comdat_behavior
== CB_WARNING
)
389 gold_warning_at_location(
391 _("relocation refers to local symbol %d "
392 "defined in discarded section"),
397 gold_warning_at_location(
399 _("relocation refers to symbol \"%s\" "
400 "defined in discarded section"),
401 gsym
->demangled_name().c_str());
404 symval2
.set_output_value(0);
406 symval2
.set_no_output_symtab_entry();
410 // If OFFSET is out of range, still let the target decide to
411 // ignore the relocation. Pass in NULL as the VIEW argument so
412 // that it can return quickly without trashing an invalid memory
414 unsigned char *v
= view
+ offset
;
415 if (offset
< 0 || static_cast<section_size_type
>(offset
) >= view_size
)
418 if (!relocate
.relocate(relinfo
, Classify_reloc::sh_type
, target
,
419 output_section
, i
, prelocs
, sym
, psymval
,
420 v
, view_address
+ offset
, view_size
))
425 gold_error_at_location(relinfo
, i
, offset
,
426 _("reloc has bad offset %zu"),
427 static_cast<size_t>(offset
));
431 if (issue_undefined_symbol_error(sym
))
432 gold_undefined_symbol_at_location(sym
, relinfo
, i
, offset
);
434 && sym
->visibility() != elfcpp::STV_DEFAULT
435 && (sym
->is_strong_undefined() || sym
->is_from_dynobj()))
436 visibility_error(sym
);
438 if (sym
!= NULL
&& sym
->has_warning())
439 relinfo
->symtab
->issue_warning(sym
, relinfo
, i
, offset
);
443 // Apply an incremental relocation.
445 template<int size
, bool big_endian
, typename Target_type
,
448 apply_relocation(const Relocate_info
<size
, big_endian
>* relinfo
,
450 typename
elfcpp::Elf_types
<size
>::Elf_Addr r_offset
,
452 typename
elfcpp::Elf_types
<size
>::Elf_Swxword r_addend
,
455 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
,
456 section_size_type view_size
)
458 // Construct the ELF relocation in a temporary buffer.
459 const int reloc_size
= elfcpp::Elf_sizes
<size
>::rela_size
;
460 unsigned char relbuf
[reloc_size
];
461 elfcpp::Rela_write
<size
, big_endian
> orel(relbuf
);
462 orel
.put_r_offset(r_offset
);
463 orel
.put_r_info(elfcpp::elf_r_info
<size
>(0, r_type
));
464 orel
.put_r_addend(r_addend
);
466 // Setup a Symbol_value for the global symbol.
467 const Sized_symbol
<size
>* sym
= static_cast<const Sized_symbol
<size
>*>(gsym
);
468 Symbol_value
<size
> symval
;
469 gold_assert(sym
->has_symtab_index() && sym
->symtab_index() != -1U);
470 symval
.set_output_symtab_index(sym
->symtab_index());
471 symval
.set_output_value(sym
->value());
472 if (gsym
->type() == elfcpp::STT_TLS
)
473 symval
.set_is_tls_symbol();
474 else if (gsym
->type() == elfcpp::STT_GNU_IFUNC
)
475 symval
.set_is_ifunc_symbol();
478 relocate
.relocate(relinfo
, elfcpp::SHT_RELA
, target
, NULL
,
479 -1U, relbuf
, sym
, &symval
,
480 view
+ r_offset
, address
+ r_offset
, view_size
);
483 // A class for inquiring about properties of a relocation,
484 // used while scanning relocs during a relocatable link and
485 // garbage collection. This class may be used as the default
486 // for SHT_RELA targets, but SHT_REL targets must implement
487 // a derived class that overrides get_size_for_reloc.
488 // The MIPS-64 target also needs to override the methods
489 // for accessing the r_sym and r_type fields of a relocation,
490 // due to its non-standard use of the r_info field.
492 template<int sh_type_
, int size
, bool big_endian
>
493 class Default_classify_reloc
496 typedef typename Reloc_types
<sh_type_
, size
, big_endian
>::Reloc
498 typedef typename Reloc_types
<sh_type_
, size
, big_endian
>::Reloc_write
500 static const int reloc_size
=
501 Reloc_types
<sh_type_
, size
, big_endian
>::reloc_size
;
502 static const int sh_type
= sh_type_
;
504 // Return the symbol referred to by the relocation.
505 static inline unsigned int
506 get_r_sym(const Reltype
* reloc
)
507 { return elfcpp::elf_r_sym
<size
>(reloc
->get_r_info()); }
509 // Return the type of the relocation.
510 static inline unsigned int
511 get_r_type(const Reltype
* reloc
)
512 { return elfcpp::elf_r_type
<size
>(reloc
->get_r_info()); }
514 // Return the explicit addend of the relocation (return 0 for SHT_REL).
515 static inline typename
elfcpp::Elf_types
<size
>::Elf_Swxword
516 get_r_addend(const Reltype
* reloc
)
517 { return Reloc_types
<sh_type_
, size
, big_endian
>::get_reloc_addend(reloc
); }
519 // Write the r_info field to a new reloc, using the r_info field from
520 // the original reloc, replacing the r_sym field with R_SYM.
522 put_r_info(Reltype_write
* new_reloc
, Reltype
* reloc
, unsigned int r_sym
)
524 unsigned int r_type
= elfcpp::elf_r_type
<size
>(reloc
->get_r_info());
525 new_reloc
->put_r_info(elfcpp::elf_r_info
<size
>(r_sym
, r_type
));
528 // Write the r_addend field to a new reloc.
530 put_r_addend(Reltype_write
* to
,
531 typename
elfcpp::Elf_types
<size
>::Elf_Swxword addend
)
532 { Reloc_types
<sh_type_
, size
, big_endian
>::set_reloc_addend(to
, addend
); }
534 // Return the size of the addend of the relocation (only used for SHT_REL).
536 get_size_for_reloc(unsigned int, Relobj
*)
543 // This class may be used as a typical class for the
544 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.
545 // This class is intended to capture the most typical target behaviour,
546 // while still permitting targets to define their own independent class
547 // for Scan_relocatable_reloc.
549 template<typename Classify_reloc
>
550 class Default_scan_relocatable_relocs
553 typedef typename
Classify_reloc::Reltype Reltype
;
554 static const int reloc_size
= Classify_reloc::reloc_size
;
555 static const int sh_type
= Classify_reloc::sh_type
;
557 // Return the symbol referred to by the relocation.
558 static inline unsigned int
559 get_r_sym(const Reltype
* reloc
)
560 { return Classify_reloc::get_r_sym(reloc
); }
562 // Return the type of the relocation.
563 static inline unsigned int
564 get_r_type(const Reltype
* reloc
)
565 { return Classify_reloc::get_r_type(reloc
); }
567 // Return the strategy to use for a local symbol which is not a
568 // section symbol, given the relocation type.
569 inline Relocatable_relocs::Reloc_strategy
570 local_non_section_strategy(unsigned int r_type
, Relobj
*, unsigned int r_sym
)
572 // We assume that relocation type 0 is NONE. Targets which are
573 // different must override.
574 if (r_type
== 0 && r_sym
== 0)
575 return Relocatable_relocs::RELOC_DISCARD
;
576 return Relocatable_relocs::RELOC_COPY
;
579 // Return the strategy to use for a local symbol which is a section
580 // symbol, given the relocation type.
581 inline Relocatable_relocs::Reloc_strategy
582 local_section_strategy(unsigned int r_type
, Relobj
* object
)
584 if (sh_type
== elfcpp::SHT_RELA
)
585 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA
;
588 switch (Classify_reloc::get_size_for_reloc(r_type
, object
))
591 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0
;
593 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1
;
595 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2
;
597 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4
;
599 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8
;
606 // Return the strategy to use for a global symbol, given the
607 // relocation type, the object, and the symbol index.
608 inline Relocatable_relocs::Reloc_strategy
609 global_strategy(unsigned int, Relobj
*, unsigned int)
610 { return Relocatable_relocs::RELOC_COPY
; }
613 // This is a strategy class used with scan_relocatable_relocs
614 // and --emit-relocs.
616 template<typename Classify_reloc
>
617 class Default_emit_relocs_strategy
620 typedef typename
Classify_reloc::Reltype Reltype
;
621 static const int reloc_size
= Classify_reloc::reloc_size
;
622 static const int sh_type
= Classify_reloc::sh_type
;
624 // Return the symbol referred to by the relocation.
625 static inline unsigned int
626 get_r_sym(const Reltype
* reloc
)
627 { return Classify_reloc::get_r_sym(reloc
); }
629 // Return the type of the relocation.
630 static inline unsigned int
631 get_r_type(const Reltype
* reloc
)
632 { return Classify_reloc::get_r_type(reloc
); }
634 // A local non-section symbol.
635 inline Relocatable_relocs::Reloc_strategy
636 local_non_section_strategy(unsigned int, Relobj
*, unsigned int)
637 { return Relocatable_relocs::RELOC_COPY
; }
639 // A local section symbol.
640 inline Relocatable_relocs::Reloc_strategy
641 local_section_strategy(unsigned int, Relobj
*)
643 if (sh_type
== elfcpp::SHT_RELA
)
644 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA
;
647 // The addend is stored in the section contents. Since this
648 // is not a relocatable link, we are going to apply the
649 // relocation contents to the section as usual. This means
650 // that we have no way to record the original addend. If the
651 // original addend is not zero, there is basically no way for
652 // the user to handle this correctly. Caveat emptor.
653 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0
;
658 inline Relocatable_relocs::Reloc_strategy
659 global_strategy(unsigned int, Relobj
*, unsigned int)
660 { return Relocatable_relocs::RELOC_COPY
; }
663 // Scan relocs during a relocatable link. This is a default
664 // definition which should work for most targets.
665 // Scan_relocatable_reloc must name a class type which provides three
666 // functions which return a Relocatable_relocs::Reloc_strategy code:
667 // global_strategy, local_non_section_strategy, and
668 // local_section_strategy. Most targets should be able to use
669 // Default_scan_relocatable_relocs as this class.
671 template<int size
, bool big_endian
, typename Scan_relocatable_reloc
>
673 scan_relocatable_relocs(
676 Sized_relobj_file
<size
, big_endian
>* object
,
677 unsigned int data_shndx
,
678 const unsigned char* prelocs
,
680 Output_section
* output_section
,
681 bool needs_special_offset_handling
,
682 size_t local_symbol_count
,
683 const unsigned char* plocal_syms
,
684 Relocatable_relocs
* rr
)
686 typedef typename
Scan_relocatable_reloc::Reltype Reltype
;
687 const int reloc_size
= Scan_relocatable_reloc::reloc_size
;
688 const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
689 Scan_relocatable_reloc scan
;
691 for (size_t i
= 0; i
< reloc_count
; ++i
, prelocs
+= reloc_size
)
693 Reltype
reloc(prelocs
);
695 Relocatable_relocs::Reloc_strategy strategy
;
697 if (needs_special_offset_handling
698 && !output_section
->is_input_address_mapped(object
, data_shndx
,
699 reloc
.get_r_offset()))
700 strategy
= Relocatable_relocs::RELOC_DISCARD
;
703 const unsigned int r_sym
= Scan_relocatable_reloc::get_r_sym(&reloc
);
704 const unsigned int r_type
=
705 Scan_relocatable_reloc::get_r_type(&reloc
);
707 if (r_sym
>= local_symbol_count
)
708 strategy
= scan
.global_strategy(r_type
, object
, r_sym
);
711 gold_assert(plocal_syms
!= NULL
);
712 typename
elfcpp::Sym
<size
, big_endian
> lsym(plocal_syms
714 unsigned int shndx
= lsym
.get_st_shndx();
716 shndx
= object
->adjust_sym_shndx(r_sym
, shndx
, &is_ordinary
);
718 && shndx
!= elfcpp::SHN_UNDEF
719 && !object
->is_section_included(shndx
))
721 // RELOC is a relocation against a local symbol
722 // defined in a section we are discarding. Discard
723 // the reloc. FIXME: Should we issue a warning?
724 strategy
= Relocatable_relocs::RELOC_DISCARD
;
726 else if (lsym
.get_st_type() != elfcpp::STT_SECTION
)
727 strategy
= scan
.local_non_section_strategy(r_type
, object
,
731 strategy
= scan
.local_section_strategy(r_type
, object
);
732 if (strategy
!= Relocatable_relocs::RELOC_DISCARD
)
733 object
->output_section(shndx
)->set_needs_symtab_index();
736 if (strategy
== Relocatable_relocs::RELOC_COPY
)
737 object
->set_must_have_output_symtab_entry(r_sym
);
741 rr
->set_next_reloc_strategy(strategy
);
745 // Relocate relocs. Called for a relocatable link, and for --emit-relocs.
746 // This is a default definition which should work for most targets.
748 template<int size
, bool big_endian
, typename Classify_reloc
>
751 const Relocate_info
<size
, big_endian
>* relinfo
,
752 const unsigned char* prelocs
,
754 Output_section
* output_section
,
755 typename
elfcpp::Elf_types
<size
>::Elf_Off offset_in_output_section
,
757 typename
elfcpp::Elf_types
<size
>::Elf_Addr view_address
,
758 section_size_type view_size
,
759 unsigned char* reloc_view
,
760 section_size_type reloc_view_size
)
762 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
763 typedef typename
Classify_reloc::Reltype Reltype
;
764 typedef typename
Classify_reloc::Reltype_write Reltype_write
;
765 const int reloc_size
= Classify_reloc::reloc_size
;
766 const Address invalid_address
= static_cast<Address
>(0) - 1;
768 Sized_relobj_file
<size
, big_endian
>* const object
= relinfo
->object
;
769 const unsigned int local_count
= object
->local_symbol_count();
771 unsigned char* pwrite
= reloc_view
;
773 const bool relocatable
= parameters
->options().relocatable();
775 for (size_t i
= 0; i
< reloc_count
; ++i
, prelocs
+= reloc_size
)
777 Relocatable_relocs::Reloc_strategy strategy
= relinfo
->rr
->strategy(i
);
778 if (strategy
== Relocatable_relocs::RELOC_DISCARD
)
781 if (strategy
== Relocatable_relocs::RELOC_SPECIAL
)
783 // Target wants to handle this relocation.
784 Sized_target
<size
, big_endian
>* target
=
785 parameters
->sized_target
<size
, big_endian
>();
786 target
->relocate_special_relocatable(relinfo
, Classify_reloc::sh_type
,
787 prelocs
, i
, output_section
,
788 offset_in_output_section
,
791 pwrite
+= reloc_size
;
794 Reltype
reloc(prelocs
);
795 Reltype_write
reloc_write(pwrite
);
797 const unsigned int r_sym
= Classify_reloc::get_r_sym(&reloc
);
799 // Get the new symbol index.
801 Output_section
* os
= NULL
;
802 unsigned int new_symndx
;
803 if (r_sym
< local_count
)
807 case Relocatable_relocs::RELOC_COPY
:
812 new_symndx
= object
->symtab_index(r_sym
);
813 gold_assert(new_symndx
!= -1U);
817 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA
:
818 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0
:
819 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1
:
820 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2
:
821 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4
:
822 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8
:
823 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED
:
825 // We are adjusting a section symbol. We need to find
826 // the symbol table index of the section symbol for
827 // the output section corresponding to input section
828 // in which this symbol is defined.
829 gold_assert(r_sym
< local_count
);
832 object
->local_symbol_input_shndx(r_sym
, &is_ordinary
);
833 gold_assert(is_ordinary
);
834 os
= object
->output_section(shndx
);
835 gold_assert(os
!= NULL
);
836 gold_assert(os
->needs_symtab_index());
837 new_symndx
= os
->symtab_index();
847 const Symbol
* gsym
= object
->global_symbol(r_sym
);
848 gold_assert(gsym
!= NULL
);
849 if (gsym
->is_forwarder())
850 gsym
= relinfo
->symtab
->resolve_forwards(gsym
);
852 gold_assert(gsym
->has_symtab_index());
853 new_symndx
= gsym
->symtab_index();
856 // Get the new offset--the location in the output section where
857 // this relocation should be applied.
859 Address offset
= reloc
.get_r_offset();
861 if (offset_in_output_section
!= invalid_address
)
862 new_offset
= offset
+ offset_in_output_section
;
865 section_offset_type sot_offset
=
866 convert_types
<section_offset_type
, Address
>(offset
);
867 section_offset_type new_sot_offset
=
868 output_section
->output_offset(object
, relinfo
->data_shndx
,
870 gold_assert(new_sot_offset
!= -1);
871 new_offset
= new_sot_offset
;
874 // In an object file, r_offset is an offset within the section.
875 // In an executable or dynamic object, generated by
876 // --emit-relocs, r_offset is an absolute address.
879 new_offset
+= view_address
;
880 if (offset_in_output_section
!= invalid_address
)
881 new_offset
-= offset_in_output_section
;
884 reloc_write
.put_r_offset(new_offset
);
885 Classify_reloc::put_r_info(&reloc_write
, &reloc
, new_symndx
);
887 // Handle the reloc addend based on the strategy.
889 if (strategy
== Relocatable_relocs::RELOC_COPY
)
891 if (Classify_reloc::sh_type
== elfcpp::SHT_RELA
)
892 Classify_reloc::put_r_addend(&reloc_write
,
893 Classify_reloc::get_r_addend(&reloc
));
897 // The relocation uses a section symbol in the input file.
898 // We are adjusting it to use a section symbol in the output
899 // file. The input section symbol refers to some address in
900 // the input section. We need the relocation in the output
901 // file to refer to that same address. This adjustment to
902 // the addend is the same calculation we use for a simple
903 // absolute relocation for the input section symbol.
905 const Symbol_value
<size
>* psymval
= object
->local_symbol(r_sym
);
907 unsigned char* padd
= view
+ offset
;
910 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA
:
912 typename
elfcpp::Elf_types
<size
>::Elf_Swxword addend
913 = Classify_reloc::get_r_addend(&reloc
);
914 addend
= psymval
->value(object
, addend
);
915 // In a relocatable link, the symbol value is relative to
916 // the start of the output section. For a non-relocatable
917 // link, we need to adjust the addend.
920 gold_assert(os
!= NULL
);
921 addend
-= os
->address();
923 Classify_reloc::put_r_addend(&reloc_write
, addend
);
927 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0
:
930 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1
:
931 Relocate_functions
<size
, big_endian
>::rel8(padd
, object
,
935 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2
:
936 Relocate_functions
<size
, big_endian
>::rel16(padd
, object
,
940 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4
:
941 Relocate_functions
<size
, big_endian
>::rel32(padd
, object
,
945 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8
:
946 Relocate_functions
<size
, big_endian
>::rel64(padd
, object
,
950 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED
:
951 Relocate_functions
<size
, big_endian
>::rel32_unaligned(padd
,
961 pwrite
+= reloc_size
;
964 gold_assert(static_cast<section_size_type
>(pwrite
- reloc_view
)
968 } // End namespace gold.
970 #endif // !defined(GOLD_TARGET_RELOC_H)