xref: /netbsd-src/external/gpl3/binutils/dist/gold/target-reloc.h (revision 7788a0781fe6ff2cce37368b4578a7ade0850cb1)
1 // target-reloc.h -- target specific relocation support  -*- C++ -*-
2 
3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5 
6 // This file is part of gold.
7 
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12 
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17 
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22 
23 #ifndef GOLD_TARGET_RELOC_H
24 #define GOLD_TARGET_RELOC_H
25 
26 #include "elfcpp.h"
27 #include "symtab.h"
28 #include "object.h"
29 #include "reloc.h"
30 #include "reloc-types.h"
31 
32 namespace gold
33 {
34 
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 // avoidmaking a function call for each relocation, and to avoid
40 // repeating the generic code for each target.
41 
42 template<int size, bool big_endian, typename Target_type, int sh_type,
43 	 typename Scan>
44 inline void
45 scan_relocs(
46     Symbol_table* symtab,
47     Layout* layout,
48     Target_type* target,
49     Sized_relobj<size, big_endian>* object,
50     unsigned int data_shndx,
51     const unsigned char* prelocs,
52     size_t reloc_count,
53     Output_section* output_section,
54     bool needs_special_offset_handling,
55     size_t local_count,
56     const unsigned char* plocal_syms)
57 {
58   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
59   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
60   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
61   Scan scan;
62 
63   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
64     {
65       Reltype reloc(prelocs);
66 
67       if (needs_special_offset_handling
68 	  && !output_section->is_input_address_mapped(object, data_shndx,
69 						      reloc.get_r_offset()))
70 	continue;
71 
72       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
73       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
74       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
75 
76       if (r_sym < local_count)
77 	{
78 	  gold_assert(plocal_syms != NULL);
79 	  typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
80 						      + r_sym * sym_size);
81 	  unsigned int shndx = lsym.get_st_shndx();
82 	  bool is_ordinary;
83 	  shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
84 	  if (is_ordinary
85 	      && shndx != elfcpp::SHN_UNDEF
86 	      && !object->is_section_included(shndx)
87               && !symtab->is_section_folded(object, shndx))
88 	    {
89 	      // RELOC is a relocation against a local symbol in a
90 	      // section we are discarding.  We can ignore this
91 	      // relocation.  It will eventually become a reloc
92 	      // against the value zero.
93 	      //
94 	      // FIXME: We should issue a warning if this is an
95 	      // allocated section; is this the best place to do it?
96 	      //
97 	      // FIXME: The old GNU linker would in some cases look
98 	      // for the linkonce section which caused this section to
99 	      // be discarded, and, if the other section was the same
100 	      // size, change the reloc to refer to the other section.
101 	      // That seems risky and weird to me, and I don't know of
102 	      // any case where it is actually required.
103 
104 	      continue;
105 	    }
106 	  scan.local(symtab, layout, target, object, data_shndx,
107 		     output_section, reloc, r_type, lsym);
108 	}
109       else
110 	{
111 	  Symbol* gsym = object->global_symbol(r_sym);
112 	  gold_assert(gsym != NULL);
113 	  if (gsym->is_forwarder())
114 	    gsym = symtab->resolve_forwards(gsym);
115 
116 	  scan.global(symtab, layout, target, object, data_shndx,
117 		      output_section, reloc, r_type, gsym);
118 	}
119     }
120 }
121 
122 // Behavior for relocations to discarded comdat sections.
123 
124 enum Comdat_behavior
125 {
126   CB_UNDETERMINED,   // Not yet determined -- need to look at section name.
127   CB_PRETEND,        // Attempt to map to the corresponding kept section.
128   CB_IGNORE,         // Ignore the relocation.
129   CB_WARNING         // Print a warning.
130 };
131 
132 // Decide what the linker should do for relocations that refer to discarded
133 // comdat sections.  This decision is based on the name of the section being
134 // relocated.
135 
136 inline Comdat_behavior
137 get_comdat_behavior(const char* name)
138 {
139   if (Layout::is_debug_info_section(name))
140     return CB_PRETEND;
141   if (strcmp(name, ".eh_frame") == 0
142       || strcmp(name, ".gcc_except_table") == 0)
143     return CB_IGNORE;
144   return CB_WARNING;
145 }
146 
147 // Give an error for a symbol with non-default visibility which is not
148 // defined locally.
149 
150 inline void
151 visibility_error(const Symbol* sym)
152 {
153   const char* v;
154   switch (sym->visibility())
155     {
156     case elfcpp::STV_INTERNAL:
157       v = _("internal");
158       break;
159     case elfcpp::STV_HIDDEN:
160       v = _("hidden");
161       break;
162     case elfcpp::STV_PROTECTED:
163       v = _("protected");
164       break;
165     default:
166       gold_unreachable();
167     }
168   gold_error(_("%s symbol '%s' is not defined locally"),
169 	     v, sym->name());
170 }
171 
172 // This function implements the generic part of relocation processing.
173 // The template parameter Relocate must be a class type which provides
174 // a single function, relocate(), which implements the machine
175 // specific part of a relocation.
176 
177 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
178 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
179 // RELOCATE implements operator() to do a relocation.
180 
181 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
182 // of relocs.  OUTPUT_SECTION is the output section.
183 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
184 // mapped to output offsets.
185 
186 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
187 // VIEW_SIZE is the size.  These refer to the input section, unless
188 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
189 // the output section.
190 
191 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support.  If it is
192 // not NULL, it is a vector indexed by relocation index.  If that
193 // entry is not NULL, it points to a global symbol which used as the
194 // symbol for the relocation, ignoring the symbol index in the
195 // relocation.
196 
197 template<int size, bool big_endian, typename Target_type, int sh_type,
198 	 typename Relocate>
199 inline void
200 relocate_section(
201     const Relocate_info<size, big_endian>* relinfo,
202     Target_type* target,
203     const unsigned char* prelocs,
204     size_t reloc_count,
205     Output_section* output_section,
206     bool needs_special_offset_handling,
207     unsigned char* view,
208     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
209     section_size_type view_size,
210     const Reloc_symbol_changes* reloc_symbol_changes)
211 {
212   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
213   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
214   Relocate relocate;
215 
216   Sized_relobj<size, big_endian>* object = relinfo->object;
217   unsigned int local_count = object->local_symbol_count();
218 
219   Comdat_behavior comdat_behavior = CB_UNDETERMINED;
220 
221   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
222     {
223       Reltype reloc(prelocs);
224 
225       section_offset_type offset =
226 	convert_to_section_size_type(reloc.get_r_offset());
227 
228       if (needs_special_offset_handling)
229 	{
230 	  offset = output_section->output_offset(relinfo->object,
231 						 relinfo->data_shndx,
232 						 offset);
233 	  if (offset == -1)
234 	    continue;
235 	}
236 
237       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
238       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
239       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
240 
241       const Sized_symbol<size>* sym;
242 
243       Symbol_value<size> symval;
244       const Symbol_value<size> *psymval;
245       bool is_defined_in_discarded_section;
246       unsigned int shndx;
247       if (r_sym < local_count
248 	  && (reloc_symbol_changes == NULL
249 	      || (*reloc_symbol_changes)[i] == NULL))
250 	{
251 	  sym = NULL;
252 	  psymval = object->local_symbol(r_sym);
253 
254           // If the local symbol belongs to a section we are discarding,
255           // and that section is a debug section, try to find the
256           // corresponding kept section and map this symbol to its
257           // counterpart in the kept section.  The symbol must not
258           // correspond to a section we are folding.
259 	  bool is_ordinary;
260 	  shndx = psymval->input_shndx(&is_ordinary);
261 	  is_defined_in_discarded_section =
262 	    (is_ordinary
263 	     && shndx != elfcpp::SHN_UNDEF
264 	     && !object->is_section_included(shndx)
265 	     && !relinfo->symtab->is_section_folded(object, shndx));
266 	}
267       else
268 	{
269 	  const Symbol* gsym;
270 	  if (reloc_symbol_changes != NULL
271 	      && (*reloc_symbol_changes)[i] != NULL)
272 	    gsym = (*reloc_symbol_changes)[i];
273 	  else
274 	    {
275 	      gsym = object->global_symbol(r_sym);
276 	      gold_assert(gsym != NULL);
277 	      if (gsym->is_forwarder())
278 		gsym = relinfo->symtab->resolve_forwards(gsym);
279 	    }
280 
281 	  sym = static_cast<const Sized_symbol<size>*>(gsym);
282 	  if (sym->has_symtab_index() && sym->symtab_index() != -1U)
283 	    symval.set_output_symtab_index(sym->symtab_index());
284 	  else
285 	    symval.set_no_output_symtab_entry();
286 	  symval.set_output_value(sym->value());
287 	  if (gsym->type() == elfcpp::STT_TLS)
288 	    symval.set_is_tls_symbol();
289 	  else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
290 	    symval.set_is_ifunc_symbol();
291 	  psymval = &symval;
292 
293 	  is_defined_in_discarded_section =
294 	    (gsym->is_defined_in_discarded_section()
295 	     && gsym->is_undefined());
296 	  shndx = 0;
297 	}
298 
299       Symbol_value<size> symval2;
300       if (is_defined_in_discarded_section)
301 	{
302 	  if (comdat_behavior == CB_UNDETERMINED)
303 	    {
304 	      std::string name = object->section_name(relinfo->data_shndx);
305 	      comdat_behavior = get_comdat_behavior(name.c_str());
306 	    }
307 	  if (comdat_behavior == CB_PRETEND)
308 	    {
309 	      // FIXME: This case does not work for global symbols.
310 	      // We have no place to store the original section index.
311 	      // Fortunately this does not matter for comdat sections,
312 	      // only for sections explicitly discarded by a linker
313 	      // script.
314 	      bool found;
315 	      typename elfcpp::Elf_types<size>::Elf_Addr value =
316 		object->map_to_kept_section(shndx, &found);
317 	      if (found)
318 		symval2.set_output_value(value + psymval->input_value());
319 	      else
320 		symval2.set_output_value(0);
321 	    }
322 	  else
323 	    {
324 	      if (comdat_behavior == CB_WARNING)
325 		gold_warning_at_location(relinfo, i, offset,
326 					 _("relocation refers to discarded "
327 					   "section"));
328 	      symval2.set_output_value(0);
329 	    }
330 	  symval2.set_no_output_symtab_entry();
331 	  psymval = &symval2;
332 	}
333 
334       if (!relocate.relocate(relinfo, target, output_section, i, reloc,
335 			     r_type, sym, psymval, view + offset,
336 			     view_address + offset, view_size))
337 	continue;
338 
339       if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
340 	{
341 	  gold_error_at_location(relinfo, i, offset,
342 				 _("reloc has bad offset %zu"),
343 				 static_cast<size_t>(offset));
344 	  continue;
345 	}
346 
347       if (sym != NULL
348 	  && (sym->is_undefined() || sym->is_placeholder())
349 	  && sym->binding() != elfcpp::STB_WEAK
350 	  && !is_defined_in_discarded_section
351           && !target->is_defined_by_abi(sym)
352 	  && (!parameters->options().shared()       // -shared
353               || parameters->options().defs()))     // -z defs
354 	gold_undefined_symbol_at_location(sym, relinfo, i, offset);
355       else if (sym != NULL
356 	       && sym->visibility() != elfcpp::STV_DEFAULT
357 	       && (sym->is_undefined() || sym->is_from_dynobj()))
358 	visibility_error(sym);
359 
360       if (sym != NULL && sym->has_warning())
361 	relinfo->symtab->issue_warning(sym, relinfo, i, offset);
362     }
363 }
364 
365 // This class may be used as a typical class for the
366 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.  The
367 // template parameter Classify_reloc must be a class type which
368 // provides a function get_size_for_reloc which returns the number of
369 // bytes to which a reloc applies.  This class is intended to capture
370 // the most typical target behaviour, while still permitting targets
371 // to define their own independent class for Scan_relocatable_reloc.
372 
373 template<int sh_type, typename Classify_reloc>
374 class Default_scan_relocatable_relocs
375 {
376  public:
377   // Return the strategy to use for a local symbol which is not a
378   // section symbol, given the relocation type.
379   inline Relocatable_relocs::Reloc_strategy
380   local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym)
381   {
382     // We assume that relocation type 0 is NONE.  Targets which are
383     // different must override.
384     if (r_type == 0 && r_sym == 0)
385       return Relocatable_relocs::RELOC_DISCARD;
386     return Relocatable_relocs::RELOC_COPY;
387   }
388 
389   // Return the strategy to use for a local symbol which is a section
390   // symbol, given the relocation type.
391   inline Relocatable_relocs::Reloc_strategy
392   local_section_strategy(unsigned int r_type, Relobj* object)
393   {
394     if (sh_type == elfcpp::SHT_RELA)
395       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
396     else
397       {
398 	Classify_reloc classify;
399 	switch (classify.get_size_for_reloc(r_type, object))
400 	  {
401 	  case 0:
402 	    return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
403 	  case 1:
404 	    return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
405 	  case 2:
406 	    return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
407 	  case 4:
408 	    return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
409 	  case 8:
410 	    return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
411 	  default:
412 	    gold_unreachable();
413 	  }
414       }
415   }
416 
417   // Return the strategy to use for a global symbol, given the
418   // relocation type, the object, and the symbol index.
419   inline Relocatable_relocs::Reloc_strategy
420   global_strategy(unsigned int, Relobj*, unsigned int)
421   { return Relocatable_relocs::RELOC_COPY; }
422 };
423 
424 // Scan relocs during a relocatable link.  This is a default
425 // definition which should work for most targets.
426 // Scan_relocatable_reloc must name a class type which provides three
427 // functions which return a Relocatable_relocs::Reloc_strategy code:
428 // global_strategy, local_non_section_strategy, and
429 // local_section_strategy.  Most targets should be able to use
430 // Default_scan_relocatable_relocs as this class.
431 
432 template<int size, bool big_endian, int sh_type,
433 	 typename Scan_relocatable_reloc>
434 void
435 scan_relocatable_relocs(
436     Symbol_table*,
437     Layout*,
438     Sized_relobj<size, big_endian>* object,
439     unsigned int data_shndx,
440     const unsigned char* prelocs,
441     size_t reloc_count,
442     Output_section* output_section,
443     bool needs_special_offset_handling,
444     size_t local_symbol_count,
445     const unsigned char* plocal_syms,
446     Relocatable_relocs* rr)
447 {
448   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
449   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
450   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
451   Scan_relocatable_reloc scan;
452 
453   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
454     {
455       Reltype reloc(prelocs);
456 
457       Relocatable_relocs::Reloc_strategy strategy;
458 
459       if (needs_special_offset_handling
460 	  && !output_section->is_input_address_mapped(object, data_shndx,
461 						      reloc.get_r_offset()))
462 	strategy = Relocatable_relocs::RELOC_DISCARD;
463       else
464 	{
465 	  typename elfcpp::Elf_types<size>::Elf_WXword r_info =
466 	    reloc.get_r_info();
467 	  const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
468 	  const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
469 
470 	  if (r_sym >= local_symbol_count)
471 	    strategy = scan.global_strategy(r_type, object, r_sym);
472 	  else
473 	    {
474 	      gold_assert(plocal_syms != NULL);
475 	      typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
476 							  + r_sym * sym_size);
477 	      unsigned int shndx = lsym.get_st_shndx();
478 	      bool is_ordinary;
479 	      shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
480 	      if (is_ordinary
481 		  && shndx != elfcpp::SHN_UNDEF
482 		  && !object->is_section_included(shndx))
483 		{
484 		  // RELOC is a relocation against a local symbol
485 		  // defined in a section we are discarding.  Discard
486 		  // the reloc.  FIXME: Should we issue a warning?
487 		  strategy = Relocatable_relocs::RELOC_DISCARD;
488 		}
489 	      else if (lsym.get_st_type() != elfcpp::STT_SECTION)
490 		strategy = scan.local_non_section_strategy(r_type, object,
491 							   r_sym);
492 	      else
493 		{
494 		  strategy = scan.local_section_strategy(r_type, object);
495 		  if (strategy != Relocatable_relocs::RELOC_DISCARD)
496                     object->output_section(shndx)->set_needs_symtab_index();
497 		}
498 
499 	      if (strategy == Relocatable_relocs::RELOC_COPY)
500 		object->set_must_have_output_symtab_entry(r_sym);
501 	    }
502 	}
503 
504       rr->set_next_reloc_strategy(strategy);
505     }
506 }
507 
508 // Relocate relocs during a relocatable link.  This is a default
509 // definition which should work for most targets.
510 
511 template<int size, bool big_endian, int sh_type>
512 void
513 relocate_for_relocatable(
514     const Relocate_info<size, big_endian>* relinfo,
515     const unsigned char* prelocs,
516     size_t reloc_count,
517     Output_section* output_section,
518     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
519     const Relocatable_relocs* rr,
520     unsigned char* view,
521     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
522     section_size_type view_size,
523     unsigned char* reloc_view,
524     section_size_type reloc_view_size)
525 {
526   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
527   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
528   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
529     Reltype_write;
530   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
531   const Address invalid_address = static_cast<Address>(0) - 1;
532 
533   Sized_relobj<size, big_endian>* const object = relinfo->object;
534   const unsigned int local_count = object->local_symbol_count();
535 
536   unsigned char* pwrite = reloc_view;
537 
538   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
539     {
540       Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
541       if (strategy == Relocatable_relocs::RELOC_DISCARD)
542 	continue;
543 
544       if (strategy == Relocatable_relocs::RELOC_SPECIAL)
545 	{
546 	  // Target wants to handle this relocation.
547 	  Sized_target<size, big_endian>* target =
548 	    parameters->sized_target<size, big_endian>();
549 	  target->relocate_special_relocatable(relinfo, sh_type, prelocs,
550 					       i, output_section,
551 					       offset_in_output_section,
552 					       view, view_address,
553 					       view_size, pwrite);
554 	  pwrite += reloc_size;
555 	  continue;
556 	}
557       Reltype reloc(prelocs);
558       Reltype_write reloc_write(pwrite);
559 
560       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
561       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
562       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
563 
564       // Get the new symbol index.
565 
566       unsigned int new_symndx;
567       if (r_sym < local_count)
568 	{
569 	  switch (strategy)
570 	    {
571 	    case Relocatable_relocs::RELOC_COPY:
572 	      if (r_sym == 0)
573 		new_symndx = 0;
574 	      else
575 		{
576 		  new_symndx = object->symtab_index(r_sym);
577 		  gold_assert(new_symndx != -1U);
578 		}
579 	      break;
580 
581 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
582 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
583 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
584 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
585 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
586 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
587 	      {
588 		// We are adjusting a section symbol.  We need to find
589 		// the symbol table index of the section symbol for
590 		// the output section corresponding to input section
591 		// in which this symbol is defined.
592 		gold_assert(r_sym < local_count);
593 		bool is_ordinary;
594 		unsigned int shndx =
595 		  object->local_symbol_input_shndx(r_sym, &is_ordinary);
596 		gold_assert(is_ordinary);
597 		Output_section* os = object->output_section(shndx);
598 		gold_assert(os != NULL);
599 		gold_assert(os->needs_symtab_index());
600 		new_symndx = os->symtab_index();
601 	      }
602 	      break;
603 
604 	    default:
605 	      gold_unreachable();
606 	    }
607 	}
608       else
609 	{
610 	  const Symbol* gsym = object->global_symbol(r_sym);
611 	  gold_assert(gsym != NULL);
612 	  if (gsym->is_forwarder())
613 	    gsym = relinfo->symtab->resolve_forwards(gsym);
614 
615 	  gold_assert(gsym->has_symtab_index());
616 	  new_symndx = gsym->symtab_index();
617 	}
618 
619       // Get the new offset--the location in the output section where
620       // this relocation should be applied.
621 
622       Address offset = reloc.get_r_offset();
623       Address new_offset;
624       if (offset_in_output_section != invalid_address)
625 	new_offset = offset + offset_in_output_section;
626       else
627 	{
628           section_offset_type sot_offset =
629               convert_types<section_offset_type, Address>(offset);
630 	  section_offset_type new_sot_offset =
631               output_section->output_offset(object, relinfo->data_shndx,
632                                             sot_offset);
633 	  gold_assert(new_sot_offset != -1);
634           new_offset = new_sot_offset;
635 	}
636 
637       // In an object file, r_offset is an offset within the section.
638       // In an executable or dynamic object, generated by
639       // --emit-relocs, r_offset is an absolute address.
640       if (!parameters->options().relocatable())
641 	{
642 	  new_offset += view_address;
643 	  if (offset_in_output_section != invalid_address)
644 	    new_offset -= offset_in_output_section;
645 	}
646 
647       reloc_write.put_r_offset(new_offset);
648       reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
649 
650       // Handle the reloc addend based on the strategy.
651 
652       if (strategy == Relocatable_relocs::RELOC_COPY)
653 	{
654 	  if (sh_type == elfcpp::SHT_RELA)
655 	    Reloc_types<sh_type, size, big_endian>::
656 	      copy_reloc_addend(&reloc_write,
657 				&reloc);
658 	}
659       else
660 	{
661 	  // The relocation uses a section symbol in the input file.
662 	  // We are adjusting it to use a section symbol in the output
663 	  // file.  The input section symbol refers to some address in
664 	  // the input section.  We need the relocation in the output
665 	  // file to refer to that same address.  This adjustment to
666 	  // the addend is the same calculation we use for a simple
667 	  // absolute relocation for the input section symbol.
668 
669 	  const Symbol_value<size>* psymval = object->local_symbol(r_sym);
670 
671 	  unsigned char* padd = view + offset;
672 	  switch (strategy)
673 	    {
674 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
675 	      {
676 		typename elfcpp::Elf_types<size>::Elf_Swxword addend;
677 		addend = Reloc_types<sh_type, size, big_endian>::
678 			   get_reloc_addend(&reloc);
679 		addend = psymval->value(object, addend);
680 		Reloc_types<sh_type, size, big_endian>::
681 		  set_reloc_addend(&reloc_write, addend);
682 	      }
683 	      break;
684 
685 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
686 	      break;
687 
688 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
689 	      Relocate_functions<size, big_endian>::rel8(padd, object,
690 							 psymval);
691 	      break;
692 
693 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
694 	      Relocate_functions<size, big_endian>::rel16(padd, object,
695 							  psymval);
696 	      break;
697 
698 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
699 	      Relocate_functions<size, big_endian>::rel32(padd, object,
700 							  psymval);
701 	      break;
702 
703 	    case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
704 	      Relocate_functions<size, big_endian>::rel64(padd, object,
705 							  psymval);
706 	      break;
707 
708 	    default:
709 	      gold_unreachable();
710 	    }
711 	}
712 
713       pwrite += reloc_size;
714     }
715 
716   gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
717 	      == reloc_view_size);
718 }
719 
720 } // End namespace gold.
721 
722 #endif // !defined(GOLD_TARGET_RELOC_H)
723