2009-06-05 Doug Kwan <dougkwan@google.com>
[deliverable/binutils-gdb.git] / gold / object.cc
1 // object.cc -- support for an object file for linking in gold
2
3 // Copyright 2006, 2007, 2008, 2009 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 #include "gold.h"
24
25 #include <cerrno>
26 #include <cstring>
27 #include <cstdarg>
28 #include "demangle.h"
29 #include "libiberty.h"
30
31 #include "gc.h"
32 #include "target-select.h"
33 #include "dwarf_reader.h"
34 #include "layout.h"
35 #include "output.h"
36 #include "symtab.h"
37 #include "cref.h"
38 #include "reloc.h"
39 #include "object.h"
40 #include "dynobj.h"
41 #include "plugin.h"
42
43 namespace gold
44 {
45
46 // Class Xindex.
47
48 // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
49 // section and read it in. SYMTAB_SHNDX is the index of the symbol
50 // table we care about.
51
52 template<int size, bool big_endian>
53 void
54 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
55 {
56 if (!this->symtab_xindex_.empty())
57 return;
58
59 gold_assert(symtab_shndx != 0);
60
61 // Look through the sections in reverse order, on the theory that it
62 // is more likely to be near the end than the beginning.
63 unsigned int i = object->shnum();
64 while (i > 0)
65 {
66 --i;
67 if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
68 && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
69 {
70 this->read_symtab_xindex<size, big_endian>(object, i, NULL);
71 return;
72 }
73 }
74
75 object->error(_("missing SHT_SYMTAB_SHNDX section"));
76 }
77
78 // Read in the symtab_xindex_ array, given the section index of the
79 // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
80 // section headers.
81
82 template<int size, bool big_endian>
83 void
84 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
85 const unsigned char* pshdrs)
86 {
87 section_size_type bytecount;
88 const unsigned char* contents;
89 if (pshdrs == NULL)
90 contents = object->section_contents(xindex_shndx, &bytecount, false);
91 else
92 {
93 const unsigned char* p = (pshdrs
94 + (xindex_shndx
95 * elfcpp::Elf_sizes<size>::shdr_size));
96 typename elfcpp::Shdr<size, big_endian> shdr(p);
97 bytecount = convert_to_section_size_type(shdr.get_sh_size());
98 contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
99 }
100
101 gold_assert(this->symtab_xindex_.empty());
102 this->symtab_xindex_.reserve(bytecount / 4);
103 for (section_size_type i = 0; i < bytecount; i += 4)
104 {
105 unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
106 // We preadjust the section indexes we save.
107 this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
108 }
109 }
110
111 // Symbol symndx has a section of SHN_XINDEX; return the real section
112 // index.
113
114 unsigned int
115 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
116 {
117 if (symndx >= this->symtab_xindex_.size())
118 {
119 object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
120 symndx);
121 return elfcpp::SHN_UNDEF;
122 }
123 unsigned int shndx = this->symtab_xindex_[symndx];
124 if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
125 {
126 object->error(_("extended index for symbol %u out of range: %u"),
127 symndx, shndx);
128 return elfcpp::SHN_UNDEF;
129 }
130 return shndx;
131 }
132
133 // Class Object.
134
135 // Set the target based on fields in the ELF file header.
136
137 void
138 Object::set_target(int machine, int size, bool big_endian, int osabi,
139 int abiversion)
140 {
141 Target* target = select_target(machine, size, big_endian, osabi, abiversion);
142 if (target == NULL)
143 gold_fatal(_("%s: unsupported ELF machine number %d"),
144 this->name().c_str(), machine);
145 this->target_ = target;
146 }
147
148 // Report an error for this object file. This is used by the
149 // elfcpp::Elf_file interface, and also called by the Object code
150 // itself.
151
152 void
153 Object::error(const char* format, ...) const
154 {
155 va_list args;
156 va_start(args, format);
157 char* buf = NULL;
158 if (vasprintf(&buf, format, args) < 0)
159 gold_nomem();
160 va_end(args);
161 gold_error(_("%s: %s"), this->name().c_str(), buf);
162 free(buf);
163 }
164
165 // Return a view of the contents of a section.
166
167 const unsigned char*
168 Object::section_contents(unsigned int shndx, section_size_type* plen,
169 bool cache)
170 {
171 Location loc(this->do_section_contents(shndx));
172 *plen = convert_to_section_size_type(loc.data_size);
173 return this->get_view(loc.file_offset, *plen, true, cache);
174 }
175
176 // Read the section data into SD. This is code common to Sized_relobj
177 // and Sized_dynobj, so we put it into Object.
178
179 template<int size, bool big_endian>
180 void
181 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
182 Read_symbols_data* sd)
183 {
184 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
185
186 // Read the section headers.
187 const off_t shoff = elf_file->shoff();
188 const unsigned int shnum = this->shnum();
189 sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
190 true, true);
191
192 // Read the section names.
193 const unsigned char* pshdrs = sd->section_headers->data();
194 const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
195 typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
196
197 if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
198 this->error(_("section name section has wrong type: %u"),
199 static_cast<unsigned int>(shdrnames.get_sh_type()));
200
201 sd->section_names_size =
202 convert_to_section_size_type(shdrnames.get_sh_size());
203 sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
204 sd->section_names_size, false,
205 false);
206 }
207
208 // If NAME is the name of a special .gnu.warning section, arrange for
209 // the warning to be issued. SHNDX is the section index. Return
210 // whether it is a warning section.
211
212 bool
213 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
214 Symbol_table* symtab)
215 {
216 const char warn_prefix[] = ".gnu.warning.";
217 const int warn_prefix_len = sizeof warn_prefix - 1;
218 if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
219 {
220 // Read the section contents to get the warning text. It would
221 // be nicer if we only did this if we have to actually issue a
222 // warning. Unfortunately, warnings are issued as we relocate
223 // sections. That means that we can not lock the object then,
224 // as we might try to issue the same warning multiple times
225 // simultaneously.
226 section_size_type len;
227 const unsigned char* contents = this->section_contents(shndx, &len,
228 false);
229 std::string warning(reinterpret_cast<const char*>(contents), len);
230 symtab->add_warning(name + warn_prefix_len, this, warning);
231 return true;
232 }
233 return false;
234 }
235
236 // Class Relobj
237
238 // To copy the symbols data read from the file to a local data structure.
239 // This function is called from do_layout only while doing garbage
240 // collection.
241
242 void
243 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
244 unsigned int section_header_size)
245 {
246 gc_sd->section_headers_data =
247 new unsigned char[(section_header_size)];
248 memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
249 section_header_size);
250 gc_sd->section_names_data =
251 new unsigned char[sd->section_names_size];
252 memcpy(gc_sd->section_names_data, sd->section_names->data(),
253 sd->section_names_size);
254 gc_sd->section_names_size = sd->section_names_size;
255 if (sd->symbols != NULL)
256 {
257 gc_sd->symbols_data =
258 new unsigned char[sd->symbols_size];
259 memcpy(gc_sd->symbols_data, sd->symbols->data(),
260 sd->symbols_size);
261 }
262 else
263 {
264 gc_sd->symbols_data = NULL;
265 }
266 gc_sd->symbols_size = sd->symbols_size;
267 gc_sd->external_symbols_offset = sd->external_symbols_offset;
268 if (sd->symbol_names != NULL)
269 {
270 gc_sd->symbol_names_data =
271 new unsigned char[sd->symbol_names_size];
272 memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
273 sd->symbol_names_size);
274 }
275 else
276 {
277 gc_sd->symbol_names_data = NULL;
278 }
279 gc_sd->symbol_names_size = sd->symbol_names_size;
280 }
281
282 // This function determines if a particular section name must be included
283 // in the link. This is used during garbage collection to determine the
284 // roots of the worklist.
285
286 bool
287 Relobj::is_section_name_included(const char* name)
288 {
289 if (is_prefix_of(".ctors", name)
290 || is_prefix_of(".dtors", name)
291 || is_prefix_of(".note", name)
292 || is_prefix_of(".init", name)
293 || is_prefix_of(".fini", name)
294 || is_prefix_of(".gcc_except_table", name)
295 || is_prefix_of(".jcr", name)
296 || is_prefix_of(".preinit_array", name)
297 || (is_prefix_of(".text", name)
298 && strstr(name, "personality"))
299 || (is_prefix_of(".data", name)
300 && strstr(name, "personality"))
301 || (is_prefix_of(".gnu.linkonce.d", name) &&
302 strstr(name, "personality")))
303 {
304 return true;
305 }
306 return false;
307 }
308
309 // Class Sized_relobj.
310
311 template<int size, bool big_endian>
312 Sized_relobj<size, big_endian>::Sized_relobj(
313 const std::string& name,
314 Input_file* input_file,
315 off_t offset,
316 const elfcpp::Ehdr<size, big_endian>& ehdr)
317 : Relobj(name, input_file, offset),
318 elf_file_(this, ehdr),
319 symtab_shndx_(-1U),
320 local_symbol_count_(0),
321 output_local_symbol_count_(0),
322 output_local_dynsym_count_(0),
323 symbols_(),
324 defined_count_(0),
325 local_symbol_offset_(0),
326 local_dynsym_offset_(0),
327 local_values_(),
328 local_got_offsets_(),
329 kept_comdat_sections_(),
330 has_eh_frame_(false),
331 discarded_eh_frame_shndx_(-1U)
332 {
333 }
334
335 template<int size, bool big_endian>
336 Sized_relobj<size, big_endian>::~Sized_relobj()
337 {
338 }
339
340 // Set up an object file based on the file header. This sets up the
341 // target and reads the section information.
342
343 template<int size, bool big_endian>
344 void
345 Sized_relobj<size, big_endian>::setup(
346 const elfcpp::Ehdr<size, big_endian>& ehdr)
347 {
348 this->set_target(ehdr.get_e_machine(), size, big_endian,
349 ehdr.get_e_ident()[elfcpp::EI_OSABI],
350 ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
351
352 const unsigned int shnum = this->elf_file_.shnum();
353 this->set_shnum(shnum);
354 }
355
356 // Find the SHT_SYMTAB section, given the section headers. The ELF
357 // standard says that maybe in the future there can be more than one
358 // SHT_SYMTAB section. Until somebody figures out how that could
359 // work, we assume there is only one.
360
361 template<int size, bool big_endian>
362 void
363 Sized_relobj<size, big_endian>::find_symtab(const unsigned char* pshdrs)
364 {
365 const unsigned int shnum = this->shnum();
366 this->symtab_shndx_ = 0;
367 if (shnum > 0)
368 {
369 // Look through the sections in reverse order, since gas tends
370 // to put the symbol table at the end.
371 const unsigned char* p = pshdrs + shnum * This::shdr_size;
372 unsigned int i = shnum;
373 unsigned int xindex_shndx = 0;
374 unsigned int xindex_link = 0;
375 while (i > 0)
376 {
377 --i;
378 p -= This::shdr_size;
379 typename This::Shdr shdr(p);
380 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
381 {
382 this->symtab_shndx_ = i;
383 if (xindex_shndx > 0 && xindex_link == i)
384 {
385 Xindex* xindex =
386 new Xindex(this->elf_file_.large_shndx_offset());
387 xindex->read_symtab_xindex<size, big_endian>(this,
388 xindex_shndx,
389 pshdrs);
390 this->set_xindex(xindex);
391 }
392 break;
393 }
394
395 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
396 // one. This will work if it follows the SHT_SYMTAB
397 // section.
398 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
399 {
400 xindex_shndx = i;
401 xindex_link = this->adjust_shndx(shdr.get_sh_link());
402 }
403 }
404 }
405 }
406
407 // Return the Xindex structure to use for object with lots of
408 // sections.
409
410 template<int size, bool big_endian>
411 Xindex*
412 Sized_relobj<size, big_endian>::do_initialize_xindex()
413 {
414 gold_assert(this->symtab_shndx_ != -1U);
415 Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
416 xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
417 return xindex;
418 }
419
420 // Return whether SHDR has the right type and flags to be a GNU
421 // .eh_frame section.
422
423 template<int size, bool big_endian>
424 bool
425 Sized_relobj<size, big_endian>::check_eh_frame_flags(
426 const elfcpp::Shdr<size, big_endian>* shdr) const
427 {
428 return (shdr->get_sh_type() == elfcpp::SHT_PROGBITS
429 && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
430 }
431
432 // Return whether there is a GNU .eh_frame section, given the section
433 // headers and the section names.
434
435 template<int size, bool big_endian>
436 bool
437 Sized_relobj<size, big_endian>::find_eh_frame(
438 const unsigned char* pshdrs,
439 const char* names,
440 section_size_type names_size) const
441 {
442 const unsigned int shnum = this->shnum();
443 const unsigned char* p = pshdrs + This::shdr_size;
444 for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
445 {
446 typename This::Shdr shdr(p);
447 if (this->check_eh_frame_flags(&shdr))
448 {
449 if (shdr.get_sh_name() >= names_size)
450 {
451 this->error(_("bad section name offset for section %u: %lu"),
452 i, static_cast<unsigned long>(shdr.get_sh_name()));
453 continue;
454 }
455
456 const char* name = names + shdr.get_sh_name();
457 if (strcmp(name, ".eh_frame") == 0)
458 return true;
459 }
460 }
461 return false;
462 }
463
464 // Read the sections and symbols from an object file.
465
466 template<int size, bool big_endian>
467 void
468 Sized_relobj<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
469 {
470 this->read_section_data(&this->elf_file_, sd);
471
472 const unsigned char* const pshdrs = sd->section_headers->data();
473
474 this->find_symtab(pshdrs);
475
476 const unsigned char* namesu = sd->section_names->data();
477 const char* names = reinterpret_cast<const char*>(namesu);
478 if (memmem(names, sd->section_names_size, ".eh_frame", 10) != NULL)
479 {
480 if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
481 this->has_eh_frame_ = true;
482 }
483
484 sd->symbols = NULL;
485 sd->symbols_size = 0;
486 sd->external_symbols_offset = 0;
487 sd->symbol_names = NULL;
488 sd->symbol_names_size = 0;
489
490 if (this->symtab_shndx_ == 0)
491 {
492 // No symbol table. Weird but legal.
493 return;
494 }
495
496 // Get the symbol table section header.
497 typename This::Shdr symtabshdr(pshdrs
498 + this->symtab_shndx_ * This::shdr_size);
499 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
500
501 // If this object has a .eh_frame section, we need all the symbols.
502 // Otherwise we only need the external symbols. While it would be
503 // simpler to just always read all the symbols, I've seen object
504 // files with well over 2000 local symbols, which for a 64-bit
505 // object file format is over 5 pages that we don't need to read
506 // now.
507
508 const int sym_size = This::sym_size;
509 const unsigned int loccount = symtabshdr.get_sh_info();
510 this->local_symbol_count_ = loccount;
511 this->local_values_.resize(loccount);
512 section_offset_type locsize = loccount * sym_size;
513 off_t dataoff = symtabshdr.get_sh_offset();
514 section_size_type datasize =
515 convert_to_section_size_type(symtabshdr.get_sh_size());
516 off_t extoff = dataoff + locsize;
517 section_size_type extsize = datasize - locsize;
518
519 off_t readoff = this->has_eh_frame_ ? dataoff : extoff;
520 section_size_type readsize = this->has_eh_frame_ ? datasize : extsize;
521
522 if (readsize == 0)
523 {
524 // No external symbols. Also weird but also legal.
525 return;
526 }
527
528 File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
529
530 // Read the section header for the symbol names.
531 unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
532 if (strtab_shndx >= this->shnum())
533 {
534 this->error(_("invalid symbol table name index: %u"), strtab_shndx);
535 return;
536 }
537 typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
538 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
539 {
540 this->error(_("symbol table name section has wrong type: %u"),
541 static_cast<unsigned int>(strtabshdr.get_sh_type()));
542 return;
543 }
544
545 // Read the symbol names.
546 File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
547 strtabshdr.get_sh_size(),
548 false, true);
549
550 sd->symbols = fvsymtab;
551 sd->symbols_size = readsize;
552 sd->external_symbols_offset = this->has_eh_frame_ ? locsize : 0;
553 sd->symbol_names = fvstrtab;
554 sd->symbol_names_size =
555 convert_to_section_size_type(strtabshdr.get_sh_size());
556 }
557
558 // Return the section index of symbol SYM. Set *VALUE to its value in
559 // the object file. Set *IS_ORDINARY if this is an ordinary section
560 // index. not a special cod between SHN_LORESERVE and SHN_HIRESERVE.
561 // Note that for a symbol which is not defined in this object file,
562 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
563 // the final value of the symbol in the link.
564
565 template<int size, bool big_endian>
566 unsigned int
567 Sized_relobj<size, big_endian>::symbol_section_and_value(unsigned int sym,
568 Address* value,
569 bool* is_ordinary)
570 {
571 section_size_type symbols_size;
572 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
573 &symbols_size,
574 false);
575
576 const size_t count = symbols_size / This::sym_size;
577 gold_assert(sym < count);
578
579 elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
580 *value = elfsym.get_st_value();
581
582 return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
583 }
584
585 // Return whether to include a section group in the link. LAYOUT is
586 // used to keep track of which section groups we have already seen.
587 // INDEX is the index of the section group and SHDR is the section
588 // header. If we do not want to include this group, we set bits in
589 // OMIT for each section which should be discarded.
590
591 template<int size, bool big_endian>
592 bool
593 Sized_relobj<size, big_endian>::include_section_group(
594 Symbol_table* symtab,
595 Layout* layout,
596 unsigned int index,
597 const char* name,
598 const unsigned char* shdrs,
599 const char* section_names,
600 section_size_type section_names_size,
601 std::vector<bool>* omit)
602 {
603 // Read the section contents.
604 typename This::Shdr shdr(shdrs + index * This::shdr_size);
605 const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
606 shdr.get_sh_size(), true, false);
607 const elfcpp::Elf_Word* pword =
608 reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
609
610 // The first word contains flags. We only care about COMDAT section
611 // groups. Other section groups are always included in the link
612 // just like ordinary sections.
613 elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
614
615 // Look up the group signature, which is the name of a symbol. This
616 // is a lot of effort to go to to read a string. Why didn't they
617 // just have the group signature point into the string table, rather
618 // than indirect through a symbol?
619
620 // Get the appropriate symbol table header (this will normally be
621 // the single SHT_SYMTAB section, but in principle it need not be).
622 const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
623 typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
624
625 // Read the symbol table entry.
626 unsigned int symndx = shdr.get_sh_info();
627 if (symndx >= symshdr.get_sh_size() / This::sym_size)
628 {
629 this->error(_("section group %u info %u out of range"),
630 index, symndx);
631 return false;
632 }
633 off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
634 const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
635 false);
636 elfcpp::Sym<size, big_endian> sym(psym);
637
638 // Read the symbol table names.
639 section_size_type symnamelen;
640 const unsigned char* psymnamesu;
641 psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
642 &symnamelen, true);
643 const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
644
645 // Get the section group signature.
646 if (sym.get_st_name() >= symnamelen)
647 {
648 this->error(_("symbol %u name offset %u out of range"),
649 symndx, sym.get_st_name());
650 return false;
651 }
652
653 std::string signature(psymnames + sym.get_st_name());
654
655 // It seems that some versions of gas will create a section group
656 // associated with a section symbol, and then fail to give a name to
657 // the section symbol. In such a case, use the name of the section.
658 if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
659 {
660 bool is_ordinary;
661 unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
662 sym.get_st_shndx(),
663 &is_ordinary);
664 if (!is_ordinary || sym_shndx >= this->shnum())
665 {
666 this->error(_("symbol %u invalid section index %u"),
667 symndx, sym_shndx);
668 return false;
669 }
670 typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
671 if (member_shdr.get_sh_name() < section_names_size)
672 signature = section_names + member_shdr.get_sh_name();
673 }
674
675 // Record this section group in the layout, and see whether we've already
676 // seen one with the same signature.
677 bool include_group;
678 Sized_relobj<size, big_endian>* kept_object = NULL;
679 Kept_section::Comdat_group* kept_group = NULL;
680
681 if ((flags & elfcpp::GRP_COMDAT) == 0)
682 include_group = true;
683 else
684 {
685 Kept_section this_group(this, index, true);
686 Kept_section *kept_section_group;
687 include_group = layout->find_or_add_kept_section(signature,
688 &this_group,
689 &kept_section_group);
690 if (include_group)
691 kept_section_group->group_sections = new Kept_section::Comdat_group;
692
693 kept_group = kept_section_group->group_sections;
694 kept_object = (static_cast<Sized_relobj<size, big_endian>*>
695 (kept_section_group->object));
696 }
697
698 size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
699
700 std::vector<unsigned int> shndxes;
701 bool relocate_group = include_group && parameters->options().relocatable();
702 if (relocate_group)
703 shndxes.reserve(count - 1);
704
705 for (size_t i = 1; i < count; ++i)
706 {
707 elfcpp::Elf_Word secnum =
708 this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
709
710 if (relocate_group)
711 shndxes.push_back(secnum);
712
713 if (secnum >= this->shnum())
714 {
715 this->error(_("section %u in section group %u out of range"),
716 secnum, index);
717 continue;
718 }
719
720 // Check for an earlier section number, since we're going to get
721 // it wrong--we may have already decided to include the section.
722 if (secnum < index)
723 this->error(_("invalid section group %u refers to earlier section %u"),
724 index, secnum);
725
726 // Get the name of the member section.
727 typename This::Shdr member_shdr(shdrs + secnum * This::shdr_size);
728 if (member_shdr.get_sh_name() >= section_names_size)
729 {
730 // This is an error, but it will be diagnosed eventually
731 // in do_layout, so we don't need to do anything here but
732 // ignore it.
733 continue;
734 }
735 std::string mname(section_names + member_shdr.get_sh_name());
736
737 if (!include_group)
738 {
739 (*omit)[secnum] = true;
740 if (kept_group != NULL)
741 {
742 // Find the corresponding kept section, and store that info
743 // in the discarded section table.
744 Kept_section::Comdat_group::const_iterator p =
745 kept_group->find(mname);
746 if (p != kept_group->end())
747 {
748 Kept_comdat_section* kept =
749 new Kept_comdat_section(kept_object, p->second);
750 this->set_kept_comdat_section(secnum, kept);
751 }
752 }
753 }
754 else if (flags & elfcpp::GRP_COMDAT)
755 {
756 // Add the section to the kept group table.
757 gold_assert(kept_group != NULL);
758 kept_group->insert(std::make_pair(mname, secnum));
759 }
760 }
761
762 if (relocate_group)
763 layout->layout_group(symtab, this, index, name, signature.c_str(),
764 shdr, flags, &shndxes);
765
766 return include_group;
767 }
768
769 // Whether to include a linkonce section in the link. NAME is the
770 // name of the section and SHDR is the section header.
771
772 // Linkonce sections are a GNU extension implemented in the original
773 // GNU linker before section groups were defined. The semantics are
774 // that we only include one linkonce section with a given name. The
775 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
776 // where T is the type of section and SYMNAME is the name of a symbol.
777 // In an attempt to make linkonce sections interact well with section
778 // groups, we try to identify SYMNAME and use it like a section group
779 // signature. We want to block section groups with that signature,
780 // but not other linkonce sections with that signature. We also use
781 // the full name of the linkonce section as a normal section group
782 // signature.
783
784 template<int size, bool big_endian>
785 bool
786 Sized_relobj<size, big_endian>::include_linkonce_section(
787 Layout* layout,
788 unsigned int index,
789 const char* name,
790 const elfcpp::Shdr<size, big_endian>&)
791 {
792 // In general the symbol name we want will be the string following
793 // the last '.'. However, we have to handle the case of
794 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
795 // some versions of gcc. So we use a heuristic: if the name starts
796 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
797 // we look for the last '.'. We can't always simply skip
798 // ".gnu.linkonce.X", because we have to deal with cases like
799 // ".gnu.linkonce.d.rel.ro.local".
800 const char* const linkonce_t = ".gnu.linkonce.t.";
801 const char* symname;
802 if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
803 symname = name + strlen(linkonce_t);
804 else
805 symname = strrchr(name, '.') + 1;
806 std::string sig1(symname);
807 std::string sig2(name);
808 Kept_section candidate1(this, index, false);
809 Kept_section candidate2(this, index, true);
810 Kept_section* kept1;
811 Kept_section* kept2;
812 bool include1 = layout->find_or_add_kept_section(sig1, &candidate1, &kept1);
813 bool include2 = layout->find_or_add_kept_section(sig2, &candidate2, &kept2);
814
815 if (!include2)
816 {
817 // The section is being discarded on the basis of its section
818 // name (i.e., the kept section was also a linkonce section).
819 // In this case, the section index stored with the layout object
820 // is the linkonce section that was kept.
821 unsigned int kept_group_index = kept2->shndx;
822 Relobj* kept_relobj = kept2->object;
823 if (kept_relobj != NULL)
824 {
825 Sized_relobj<size, big_endian>* kept_object =
826 static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
827 Kept_comdat_section* kept =
828 new Kept_comdat_section(kept_object, kept_group_index);
829 this->set_kept_comdat_section(index, kept);
830 }
831 }
832 else if (!include1)
833 {
834 // The section is being discarded on the basis of its symbol
835 // name. This means that the corresponding kept section was
836 // part of a comdat group, and it will be difficult to identify
837 // the specific section within that group that corresponds to
838 // this linkonce section. We'll handle the simple case where
839 // the group has only one member section. Otherwise, it's not
840 // worth the effort.
841 Relobj* kept_relobj = kept1->object;
842 if (kept_relobj != NULL)
843 {
844 Sized_relobj<size, big_endian>* kept_object =
845 static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
846 Kept_section::Comdat_group* kept_group = kept1->group_sections;
847 if (kept_group != NULL && kept_group->size() == 1)
848 {
849 Kept_section::Comdat_group::const_iterator p =
850 kept_group->begin();
851 gold_assert(p != kept_group->end());
852 Kept_comdat_section* kept =
853 new Kept_comdat_section(kept_object, p->second);
854 this->set_kept_comdat_section(index, kept);
855 }
856 }
857 }
858
859 return include1 && include2;
860 }
861
862 // Layout an input section.
863
864 template<int size, bool big_endian>
865 inline void
866 Sized_relobj<size, big_endian>::layout_section(Layout* layout,
867 unsigned int shndx,
868 const char* name,
869 typename This::Shdr& shdr,
870 unsigned int reloc_shndx,
871 unsigned int reloc_type)
872 {
873 off_t offset;
874 Output_section* os = layout->layout(this, shndx, name, shdr,
875 reloc_shndx, reloc_type, &offset);
876
877 this->output_sections()[shndx] = os;
878 if (offset == -1)
879 this->section_offsets_[shndx] = invalid_address;
880 else
881 this->section_offsets_[shndx] = convert_types<Address, off_t>(offset);
882
883 // If this section requires special handling, and if there are
884 // relocs that apply to it, then we must do the special handling
885 // before we apply the relocs.
886 if (offset == -1 && reloc_shndx != 0)
887 this->set_relocs_must_follow_section_writes();
888 }
889
890 // Lay out the input sections. We walk through the sections and check
891 // whether they should be included in the link. If they should, we
892 // pass them to the Layout object, which will return an output section
893 // and an offset.
894 // During garbage collection (gc-sections), this function is called
895 // twice. When it is called the first time, it is for setting up some
896 // sections as roots to a work-list and to do comdat processing. Actual
897 // layout happens the second time around after all the relevant sections
898 // have been determined. The first time, is_worklist_ready is false.
899 // It is then set to true after the worklist is processed and the relevant
900 // sections are determined. Then, this function is called again to
901 // layout the sections.
902
903 template<int size, bool big_endian>
904 void
905 Sized_relobj<size, big_endian>::do_layout(Symbol_table* symtab,
906 Layout* layout,
907 Read_symbols_data* sd)
908 {
909 const unsigned int shnum = this->shnum();
910 bool is_gc_pass_one = (parameters->options().gc_sections()
911 && !symtab->gc()->is_worklist_ready());
912 bool is_gc_pass_two = (parameters->options().gc_sections()
913 && symtab->gc()->is_worklist_ready());
914 if (shnum == 0)
915 return;
916 Symbols_data* gc_sd = NULL;
917 if (is_gc_pass_one)
918 {
919 // During garbage collection save the symbols data to use it when
920 // re-entering this function.
921 gc_sd = new Symbols_data;
922 this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
923 this->set_symbols_data(gc_sd);
924 }
925 else if (is_gc_pass_two)
926 {
927 gc_sd = this->get_symbols_data();
928 }
929
930 const unsigned char* section_headers_data = NULL;
931 section_size_type section_names_size;
932 const unsigned char* symbols_data = NULL;
933 section_size_type symbols_size;
934 section_offset_type external_symbols_offset;
935 const unsigned char* symbol_names_data = NULL;
936 section_size_type symbol_names_size;
937
938 if (parameters->options().gc_sections())
939 {
940 section_headers_data = gc_sd->section_headers_data;
941 section_names_size = gc_sd->section_names_size;
942 symbols_data = gc_sd->symbols_data;
943 symbols_size = gc_sd->symbols_size;
944 external_symbols_offset = gc_sd->external_symbols_offset;
945 symbol_names_data = gc_sd->symbol_names_data;
946 symbol_names_size = gc_sd->symbol_names_size;
947 }
948 else
949 {
950 section_headers_data = sd->section_headers->data();
951 section_names_size = sd->section_names_size;
952 if (sd->symbols != NULL)
953 symbols_data = sd->symbols->data();
954 symbols_size = sd->symbols_size;
955 external_symbols_offset = sd->external_symbols_offset;
956 if (sd->symbol_names != NULL)
957 symbol_names_data = sd->symbol_names->data();
958 symbol_names_size = sd->symbol_names_size;
959 }
960
961 // Get the section headers.
962 const unsigned char* shdrs = section_headers_data;
963 const unsigned char* pshdrs;
964
965 // Get the section names.
966 const unsigned char* pnamesu = parameters->options().gc_sections() ?
967 gc_sd->section_names_data :
968 sd->section_names->data();
969 const char* pnames = reinterpret_cast<const char*>(pnamesu);
970
971 // If any input files have been claimed by plugins, we need to defer
972 // actual layout until the replacement files have arrived.
973 const bool should_defer_layout =
974 (parameters->options().has_plugins()
975 && parameters->options().plugins()->should_defer_layout());
976 unsigned int num_sections_to_defer = 0;
977
978 // For each section, record the index of the reloc section if any.
979 // Use 0 to mean that there is no reloc section, -1U to mean that
980 // there is more than one.
981 std::vector<unsigned int> reloc_shndx(shnum, 0);
982 std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
983 // Skip the first, dummy, section.
984 pshdrs = shdrs + This::shdr_size;
985 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
986 {
987 typename This::Shdr shdr(pshdrs);
988
989 // Count the number of sections whose layout will be deferred.
990 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
991 ++num_sections_to_defer;
992
993 unsigned int sh_type = shdr.get_sh_type();
994 if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
995 {
996 unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
997 if (target_shndx == 0 || target_shndx >= shnum)
998 {
999 this->error(_("relocation section %u has bad info %u"),
1000 i, target_shndx);
1001 continue;
1002 }
1003
1004 if (reloc_shndx[target_shndx] != 0)
1005 reloc_shndx[target_shndx] = -1U;
1006 else
1007 {
1008 reloc_shndx[target_shndx] = i;
1009 reloc_type[target_shndx] = sh_type;
1010 }
1011 }
1012 }
1013
1014 Output_sections& out_sections(this->output_sections());
1015 std::vector<Address>& out_section_offsets(this->section_offsets_);
1016
1017 if (!is_gc_pass_two)
1018 {
1019 out_sections.resize(shnum);
1020 out_section_offsets.resize(shnum);
1021 }
1022
1023 // If we are only linking for symbols, then there is nothing else to
1024 // do here.
1025 if (this->input_file()->just_symbols())
1026 {
1027 if (!is_gc_pass_two)
1028 {
1029 delete sd->section_headers;
1030 sd->section_headers = NULL;
1031 delete sd->section_names;
1032 sd->section_names = NULL;
1033 }
1034 return;
1035 }
1036
1037 if (num_sections_to_defer > 0)
1038 {
1039 parameters->options().plugins()->add_deferred_layout_object(this);
1040 this->deferred_layout_.reserve(num_sections_to_defer);
1041 }
1042
1043 // Whether we've seen a .note.GNU-stack section.
1044 bool seen_gnu_stack = false;
1045 // The flags of a .note.GNU-stack section.
1046 uint64_t gnu_stack_flags = 0;
1047
1048 // Keep track of which sections to omit.
1049 std::vector<bool> omit(shnum, false);
1050
1051 // Keep track of reloc sections when emitting relocations.
1052 const bool relocatable = parameters->options().relocatable();
1053 const bool emit_relocs = (relocatable
1054 || parameters->options().emit_relocs());
1055 std::vector<unsigned int> reloc_sections;
1056
1057 // Keep track of .eh_frame sections.
1058 std::vector<unsigned int> eh_frame_sections;
1059
1060 // Skip the first, dummy, section.
1061 pshdrs = shdrs + This::shdr_size;
1062 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1063 {
1064 typename This::Shdr shdr(pshdrs);
1065
1066 if (shdr.get_sh_name() >= section_names_size)
1067 {
1068 this->error(_("bad section name offset for section %u: %lu"),
1069 i, static_cast<unsigned long>(shdr.get_sh_name()));
1070 return;
1071 }
1072
1073 const char* name = pnames + shdr.get_sh_name();
1074
1075 if (!is_gc_pass_two)
1076 {
1077 if (this->handle_gnu_warning_section(name, i, symtab))
1078 {
1079 if (!relocatable)
1080 omit[i] = true;
1081 }
1082
1083 // The .note.GNU-stack section is special. It gives the
1084 // protection flags that this object file requires for the stack
1085 // in memory.
1086 if (strcmp(name, ".note.GNU-stack") == 0)
1087 {
1088 seen_gnu_stack = true;
1089 gnu_stack_flags |= shdr.get_sh_flags();
1090 omit[i] = true;
1091 }
1092
1093 bool discard = omit[i];
1094 if (!discard)
1095 {
1096 if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1097 {
1098 if (!this->include_section_group(symtab, layout, i, name,
1099 shdrs, pnames,
1100 section_names_size,
1101 &omit))
1102 discard = true;
1103 }
1104 else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1105 && Layout::is_linkonce(name))
1106 {
1107 if (!this->include_linkonce_section(layout, i, name, shdr))
1108 discard = true;
1109 }
1110 }
1111
1112 if (discard)
1113 {
1114 // Do not include this section in the link.
1115 out_sections[i] = NULL;
1116 out_section_offsets[i] = invalid_address;
1117 continue;
1118 }
1119 }
1120
1121 if (is_gc_pass_one)
1122 {
1123 if (is_section_name_included(name)
1124 || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1125 || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1126 {
1127 symtab->gc()->worklist().push(Section_id(this, i));
1128 }
1129 }
1130
1131 // When doing a relocatable link we are going to copy input
1132 // reloc sections into the output. We only want to copy the
1133 // ones associated with sections which are not being discarded.
1134 // However, we don't know that yet for all sections. So save
1135 // reloc sections and process them later. Garbage collection is
1136 // not triggered when relocatable code is desired.
1137 if (emit_relocs
1138 && (shdr.get_sh_type() == elfcpp::SHT_REL
1139 || shdr.get_sh_type() == elfcpp::SHT_RELA))
1140 {
1141 reloc_sections.push_back(i);
1142 continue;
1143 }
1144
1145 if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1146 continue;
1147
1148 // The .eh_frame section is special. It holds exception frame
1149 // information that we need to read in order to generate the
1150 // exception frame header. We process these after all the other
1151 // sections so that the exception frame reader can reliably
1152 // determine which sections are being discarded, and discard the
1153 // corresponding information.
1154 if (!relocatable
1155 && strcmp(name, ".eh_frame") == 0
1156 && this->check_eh_frame_flags(&shdr))
1157 {
1158 if (is_gc_pass_one)
1159 {
1160 out_sections[i] = reinterpret_cast<Output_section*>(1);
1161 out_section_offsets[i] = invalid_address;
1162 }
1163 else
1164 eh_frame_sections.push_back(i);
1165 continue;
1166 }
1167
1168 if (is_gc_pass_two)
1169 {
1170 // This is executed during the second pass of garbage
1171 // collection. do_layout has been called before and some
1172 // sections have been already discarded. Simply ignore
1173 // such sections this time around.
1174 if (out_sections[i] == NULL)
1175 {
1176 gold_assert(out_section_offsets[i] == invalid_address);
1177 continue;
1178 }
1179 if ((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1180 if (symtab->gc()->referenced_list().find(Section_id(this,i))
1181 == symtab->gc()->referenced_list().end())
1182 {
1183 if (parameters->options().print_gc_sections())
1184 gold_info(_("%s: removing unused section from '%s'"
1185 " in file '%s"),
1186 program_name, this->section_name(i).c_str(),
1187 this->name().c_str());
1188 out_sections[i] = NULL;
1189 out_section_offsets[i] = invalid_address;
1190 continue;
1191 }
1192 }
1193 // Defer layout here if input files are claimed by plugins. When gc
1194 // is turned on this function is called twice. For the second call
1195 // should_defer_layout should be false.
1196 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1197 {
1198 gold_assert(!is_gc_pass_two);
1199 this->deferred_layout_.push_back(Deferred_layout(i, name,
1200 pshdrs,
1201 reloc_shndx[i],
1202 reloc_type[i]));
1203 // Put dummy values here; real values will be supplied by
1204 // do_layout_deferred_sections.
1205 out_sections[i] = reinterpret_cast<Output_section*>(2);
1206 out_section_offsets[i] = invalid_address;
1207 continue;
1208 }
1209 // During gc_pass_two if a section that was previously deferred is
1210 // found, do not layout the section as layout_deferred_sections will
1211 // do it later from gold.cc.
1212 if (is_gc_pass_two
1213 && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1214 continue;
1215
1216 if (is_gc_pass_one)
1217 {
1218 // This is during garbage collection. The out_sections are
1219 // assigned in the second call to this function.
1220 out_sections[i] = reinterpret_cast<Output_section*>(1);
1221 out_section_offsets[i] = invalid_address;
1222 }
1223 else
1224 {
1225 // When garbage collection is switched on the actual layout
1226 // only happens in the second call.
1227 this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1228 reloc_type[i]);
1229 }
1230 }
1231
1232 if (!is_gc_pass_one)
1233 layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags);
1234
1235 // When doing a relocatable link handle the reloc sections at the
1236 // end. Garbage collection is not turned on for relocatable code.
1237 if (emit_relocs)
1238 this->size_relocatable_relocs();
1239 gold_assert(!parameters->options().gc_sections() || reloc_sections.empty());
1240 for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1241 p != reloc_sections.end();
1242 ++p)
1243 {
1244 unsigned int i = *p;
1245 const unsigned char* pshdr;
1246 pshdr = section_headers_data + i * This::shdr_size;
1247 typename This::Shdr shdr(pshdr);
1248
1249 unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1250 if (data_shndx >= shnum)
1251 {
1252 // We already warned about this above.
1253 continue;
1254 }
1255
1256 Output_section* data_section = out_sections[data_shndx];
1257 if (data_section == NULL)
1258 {
1259 out_sections[i] = NULL;
1260 out_section_offsets[i] = invalid_address;
1261 continue;
1262 }
1263
1264 Relocatable_relocs* rr = new Relocatable_relocs();
1265 this->set_relocatable_relocs(i, rr);
1266
1267 Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1268 rr);
1269 out_sections[i] = os;
1270 out_section_offsets[i] = invalid_address;
1271 }
1272
1273 // Handle the .eh_frame sections at the end.
1274 gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
1275 for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1276 p != eh_frame_sections.end();
1277 ++p)
1278 {
1279 gold_assert(this->has_eh_frame_);
1280 gold_assert(external_symbols_offset != 0);
1281
1282 unsigned int i = *p;
1283 const unsigned char *pshdr;
1284 pshdr = section_headers_data + i * This::shdr_size;
1285 typename This::Shdr shdr(pshdr);
1286
1287 off_t offset;
1288 Output_section* os = layout->layout_eh_frame(this,
1289 symbols_data,
1290 symbols_size,
1291 symbol_names_data,
1292 symbol_names_size,
1293 i, shdr,
1294 reloc_shndx[i],
1295 reloc_type[i],
1296 &offset);
1297 out_sections[i] = os;
1298 if (offset == -1)
1299 {
1300 // An object can contain at most one section holding exception
1301 // frame information.
1302 gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1303 this->discarded_eh_frame_shndx_ = i;
1304 out_section_offsets[i] = invalid_address;
1305 }
1306 else
1307 out_section_offsets[i] = convert_types<Address, off_t>(offset);
1308
1309 // If this section requires special handling, and if there are
1310 // relocs that apply to it, then we must do the special handling
1311 // before we apply the relocs.
1312 if (offset == -1 && reloc_shndx[i] != 0)
1313 this->set_relocs_must_follow_section_writes();
1314 }
1315
1316 if (is_gc_pass_two)
1317 {
1318 delete[] gc_sd->section_headers_data;
1319 delete[] gc_sd->section_names_data;
1320 delete[] gc_sd->symbols_data;
1321 delete[] gc_sd->symbol_names_data;
1322 }
1323 else
1324 {
1325 delete sd->section_headers;
1326 sd->section_headers = NULL;
1327 delete sd->section_names;
1328 sd->section_names = NULL;
1329 }
1330 }
1331
1332 // Layout sections whose layout was deferred while waiting for
1333 // input files from a plugin.
1334
1335 template<int size, bool big_endian>
1336 void
1337 Sized_relobj<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1338 {
1339 typename std::vector<Deferred_layout>::iterator deferred;
1340
1341 for (deferred = this->deferred_layout_.begin();
1342 deferred != this->deferred_layout_.end();
1343 ++deferred)
1344 {
1345 typename This::Shdr shdr(deferred->shdr_data_);
1346 this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1347 shdr, deferred->reloc_shndx_, deferred->reloc_type_);
1348 }
1349
1350 this->deferred_layout_.clear();
1351 }
1352
1353 // Add the symbols to the symbol table.
1354
1355 template<int size, bool big_endian>
1356 void
1357 Sized_relobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1358 Read_symbols_data* sd,
1359 Layout*)
1360 {
1361 if (sd->symbols == NULL)
1362 {
1363 gold_assert(sd->symbol_names == NULL);
1364 return;
1365 }
1366
1367 const int sym_size = This::sym_size;
1368 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1369 / sym_size);
1370 if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1371 {
1372 this->error(_("size of symbols is not multiple of symbol size"));
1373 return;
1374 }
1375
1376 this->symbols_.resize(symcount);
1377
1378 const char* sym_names =
1379 reinterpret_cast<const char*>(sd->symbol_names->data());
1380 symtab->add_from_relobj(this,
1381 sd->symbols->data() + sd->external_symbols_offset,
1382 symcount, this->local_symbol_count_,
1383 sym_names, sd->symbol_names_size,
1384 &this->symbols_,
1385 &this->defined_count_);
1386
1387 delete sd->symbols;
1388 sd->symbols = NULL;
1389 delete sd->symbol_names;
1390 sd->symbol_names = NULL;
1391 }
1392
1393 // First pass over the local symbols. Here we add their names to
1394 // *POOL and *DYNPOOL, and we store the symbol value in
1395 // THIS->LOCAL_VALUES_. This function is always called from a
1396 // singleton thread. This is followed by a call to
1397 // finalize_local_symbols.
1398
1399 template<int size, bool big_endian>
1400 void
1401 Sized_relobj<size, big_endian>::do_count_local_symbols(Stringpool* pool,
1402 Stringpool* dynpool)
1403 {
1404 gold_assert(this->symtab_shndx_ != -1U);
1405 if (this->symtab_shndx_ == 0)
1406 {
1407 // This object has no symbols. Weird but legal.
1408 return;
1409 }
1410
1411 // Read the symbol table section header.
1412 const unsigned int symtab_shndx = this->symtab_shndx_;
1413 typename This::Shdr symtabshdr(this,
1414 this->elf_file_.section_header(symtab_shndx));
1415 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1416
1417 // Read the local symbols.
1418 const int sym_size = This::sym_size;
1419 const unsigned int loccount = this->local_symbol_count_;
1420 gold_assert(loccount == symtabshdr.get_sh_info());
1421 off_t locsize = loccount * sym_size;
1422 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1423 locsize, true, true);
1424
1425 // Read the symbol names.
1426 const unsigned int strtab_shndx =
1427 this->adjust_shndx(symtabshdr.get_sh_link());
1428 section_size_type strtab_size;
1429 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1430 &strtab_size,
1431 true);
1432 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1433
1434 // Loop over the local symbols.
1435
1436 const Output_sections& out_sections(this->output_sections());
1437 unsigned int shnum = this->shnum();
1438 unsigned int count = 0;
1439 unsigned int dyncount = 0;
1440 // Skip the first, dummy, symbol.
1441 psyms += sym_size;
1442 bool discard_locals = parameters->options().discard_locals();
1443 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1444 {
1445 elfcpp::Sym<size, big_endian> sym(psyms);
1446
1447 Symbol_value<size>& lv(this->local_values_[i]);
1448
1449 bool is_ordinary;
1450 unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1451 &is_ordinary);
1452 lv.set_input_shndx(shndx, is_ordinary);
1453
1454 if (sym.get_st_type() == elfcpp::STT_SECTION)
1455 lv.set_is_section_symbol();
1456 else if (sym.get_st_type() == elfcpp::STT_TLS)
1457 lv.set_is_tls_symbol();
1458
1459 // Save the input symbol value for use in do_finalize_local_symbols().
1460 lv.set_input_value(sym.get_st_value());
1461
1462 // Decide whether this symbol should go into the output file.
1463
1464 if ((shndx < shnum && out_sections[shndx] == NULL)
1465 || (shndx == this->discarded_eh_frame_shndx_))
1466 {
1467 lv.set_no_output_symtab_entry();
1468 gold_assert(!lv.needs_output_dynsym_entry());
1469 continue;
1470 }
1471
1472 if (sym.get_st_type() == elfcpp::STT_SECTION)
1473 {
1474 lv.set_no_output_symtab_entry();
1475 gold_assert(!lv.needs_output_dynsym_entry());
1476 continue;
1477 }
1478
1479 if (sym.get_st_name() >= strtab_size)
1480 {
1481 this->error(_("local symbol %u section name out of range: %u >= %u"),
1482 i, sym.get_st_name(),
1483 static_cast<unsigned int>(strtab_size));
1484 lv.set_no_output_symtab_entry();
1485 continue;
1486 }
1487
1488 // If --discard-locals option is used, discard all temporary local
1489 // symbols. These symbols start with system-specific local label
1490 // prefixes, typically .L for ELF system. We want to be compatible
1491 // with GNU ld so here we essentially use the same check in
1492 // bfd_is_local_label(). The code is different because we already
1493 // know that:
1494 //
1495 // - the symbol is local and thus cannot have global or weak binding.
1496 // - the symbol is not a section symbol.
1497 // - the symbol has a name.
1498 //
1499 // We do not discard a symbol if it needs a dynamic symbol entry.
1500 const char* name = pnames + sym.get_st_name();
1501 if (discard_locals
1502 && sym.get_st_type() != elfcpp::STT_FILE
1503 && !lv.needs_output_dynsym_entry()
1504 && parameters->target().is_local_label_name(name))
1505 {
1506 lv.set_no_output_symtab_entry();
1507 continue;
1508 }
1509
1510 // Add the symbol to the symbol table string pool.
1511 pool->add(name, true, NULL);
1512 ++count;
1513
1514 // If needed, add the symbol to the dynamic symbol table string pool.
1515 if (lv.needs_output_dynsym_entry())
1516 {
1517 dynpool->add(name, true, NULL);
1518 ++dyncount;
1519 }
1520 }
1521
1522 this->output_local_symbol_count_ = count;
1523 this->output_local_dynsym_count_ = dyncount;
1524 }
1525
1526 // Finalize the local symbols. Here we set the final value in
1527 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
1528 // This function is always called from a singleton thread. The actual
1529 // output of the local symbols will occur in a separate task.
1530
1531 template<int size, bool big_endian>
1532 unsigned int
1533 Sized_relobj<size, big_endian>::do_finalize_local_symbols(unsigned int index,
1534 off_t off)
1535 {
1536 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1537
1538 const unsigned int loccount = this->local_symbol_count_;
1539 this->local_symbol_offset_ = off;
1540
1541 const bool relocatable = parameters->options().relocatable();
1542 const Output_sections& out_sections(this->output_sections());
1543 const std::vector<Address>& out_offsets(this->section_offsets_);
1544 unsigned int shnum = this->shnum();
1545
1546 for (unsigned int i = 1; i < loccount; ++i)
1547 {
1548 Symbol_value<size>& lv(this->local_values_[i]);
1549
1550 bool is_ordinary;
1551 unsigned int shndx = lv.input_shndx(&is_ordinary);
1552
1553 // Set the output symbol value.
1554
1555 if (!is_ordinary)
1556 {
1557 if (shndx == elfcpp::SHN_ABS || shndx == elfcpp::SHN_COMMON)
1558 lv.set_output_value(lv.input_value());
1559 else
1560 {
1561 this->error(_("unknown section index %u for local symbol %u"),
1562 shndx, i);
1563 lv.set_output_value(0);
1564 }
1565 }
1566 else
1567 {
1568 if (shndx >= shnum)
1569 {
1570 this->error(_("local symbol %u section index %u out of range"),
1571 i, shndx);
1572 shndx = 0;
1573 }
1574
1575 Output_section* os = out_sections[shndx];
1576
1577 if (os == NULL)
1578 {
1579 // This local symbol belongs to a section we are discarding.
1580 // In some cases when applying relocations later, we will
1581 // attempt to match it to the corresponding kept section,
1582 // so we leave the input value unchanged here.
1583 continue;
1584 }
1585 else if (out_offsets[shndx] == invalid_address)
1586 {
1587 uint64_t start;
1588
1589 // This is a SHF_MERGE section or one which otherwise
1590 // requires special handling.
1591 if (shndx == this->discarded_eh_frame_shndx_)
1592 {
1593 // This local symbol belongs to a discarded .eh_frame
1594 // section. Just treat it like the case in which
1595 // os == NULL above.
1596 gold_assert(this->has_eh_frame_);
1597 continue;
1598 }
1599 else if (!lv.is_section_symbol())
1600 {
1601 // This is not a section symbol. We can determine
1602 // the final value now.
1603 lv.set_output_value(os->output_address(this, shndx,
1604 lv.input_value()));
1605 }
1606 else if (!os->find_starting_output_address(this, shndx, &start))
1607 {
1608 // This is a section symbol, but apparently not one
1609 // in a merged section. Just use the start of the
1610 // output section. This happens with relocatable
1611 // links when the input object has section symbols
1612 // for arbitrary non-merge sections.
1613 lv.set_output_value(os->address());
1614 }
1615 else
1616 {
1617 // We have to consider the addend to determine the
1618 // value to use in a relocation. START is the start
1619 // of this input section.
1620 Merged_symbol_value<size>* msv =
1621 new Merged_symbol_value<size>(lv.input_value(), start);
1622 lv.set_merged_symbol_value(msv);
1623 }
1624 }
1625 else if (lv.is_tls_symbol())
1626 lv.set_output_value(os->tls_offset()
1627 + out_offsets[shndx]
1628 + lv.input_value());
1629 else
1630 lv.set_output_value((relocatable ? 0 : os->address())
1631 + out_offsets[shndx]
1632 + lv.input_value());
1633 }
1634
1635 if (lv.needs_output_symtab_entry())
1636 {
1637 lv.set_output_symtab_index(index);
1638 ++index;
1639 }
1640 }
1641 return index;
1642 }
1643
1644 // Set the output dynamic symbol table indexes for the local variables.
1645
1646 template<int size, bool big_endian>
1647 unsigned int
1648 Sized_relobj<size, big_endian>::do_set_local_dynsym_indexes(unsigned int index)
1649 {
1650 const unsigned int loccount = this->local_symbol_count_;
1651 for (unsigned int i = 1; i < loccount; ++i)
1652 {
1653 Symbol_value<size>& lv(this->local_values_[i]);
1654 if (lv.needs_output_dynsym_entry())
1655 {
1656 lv.set_output_dynsym_index(index);
1657 ++index;
1658 }
1659 }
1660 return index;
1661 }
1662
1663 // Set the offset where local dynamic symbol information will be stored.
1664 // Returns the count of local symbols contributed to the symbol table by
1665 // this object.
1666
1667 template<int size, bool big_endian>
1668 unsigned int
1669 Sized_relobj<size, big_endian>::do_set_local_dynsym_offset(off_t off)
1670 {
1671 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1672 this->local_dynsym_offset_ = off;
1673 return this->output_local_dynsym_count_;
1674 }
1675
1676 // Write out the local symbols.
1677
1678 template<int size, bool big_endian>
1679 void
1680 Sized_relobj<size, big_endian>::write_local_symbols(
1681 Output_file* of,
1682 const Stringpool* sympool,
1683 const Stringpool* dynpool,
1684 Output_symtab_xindex* symtab_xindex,
1685 Output_symtab_xindex* dynsym_xindex)
1686 {
1687 const bool strip_all = parameters->options().strip_all();
1688 if (strip_all)
1689 {
1690 if (this->output_local_dynsym_count_ == 0)
1691 return;
1692 this->output_local_symbol_count_ = 0;
1693 }
1694
1695 gold_assert(this->symtab_shndx_ != -1U);
1696 if (this->symtab_shndx_ == 0)
1697 {
1698 // This object has no symbols. Weird but legal.
1699 return;
1700 }
1701
1702 // Read the symbol table section header.
1703 const unsigned int symtab_shndx = this->symtab_shndx_;
1704 typename This::Shdr symtabshdr(this,
1705 this->elf_file_.section_header(symtab_shndx));
1706 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1707 const unsigned int loccount = this->local_symbol_count_;
1708 gold_assert(loccount == symtabshdr.get_sh_info());
1709
1710 // Read the local symbols.
1711 const int sym_size = This::sym_size;
1712 off_t locsize = loccount * sym_size;
1713 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1714 locsize, true, false);
1715
1716 // Read the symbol names.
1717 const unsigned int strtab_shndx =
1718 this->adjust_shndx(symtabshdr.get_sh_link());
1719 section_size_type strtab_size;
1720 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1721 &strtab_size,
1722 false);
1723 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1724
1725 // Get views into the output file for the portions of the symbol table
1726 // and the dynamic symbol table that we will be writing.
1727 off_t output_size = this->output_local_symbol_count_ * sym_size;
1728 unsigned char* oview = NULL;
1729 if (output_size > 0)
1730 oview = of->get_output_view(this->local_symbol_offset_, output_size);
1731
1732 off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
1733 unsigned char* dyn_oview = NULL;
1734 if (dyn_output_size > 0)
1735 dyn_oview = of->get_output_view(this->local_dynsym_offset_,
1736 dyn_output_size);
1737
1738 const Output_sections out_sections(this->output_sections());
1739
1740 gold_assert(this->local_values_.size() == loccount);
1741
1742 unsigned char* ov = oview;
1743 unsigned char* dyn_ov = dyn_oview;
1744 psyms += sym_size;
1745 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1746 {
1747 elfcpp::Sym<size, big_endian> isym(psyms);
1748
1749 Symbol_value<size>& lv(this->local_values_[i]);
1750
1751 bool is_ordinary;
1752 unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1753 &is_ordinary);
1754 if (is_ordinary)
1755 {
1756 gold_assert(st_shndx < out_sections.size());
1757 if (out_sections[st_shndx] == NULL)
1758 continue;
1759 st_shndx = out_sections[st_shndx]->out_shndx();
1760 if (st_shndx >= elfcpp::SHN_LORESERVE)
1761 {
1762 if (lv.needs_output_symtab_entry() && !strip_all)
1763 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
1764 if (lv.needs_output_dynsym_entry())
1765 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
1766 st_shndx = elfcpp::SHN_XINDEX;
1767 }
1768 }
1769
1770 // Write the symbol to the output symbol table.
1771 if (!strip_all && lv.needs_output_symtab_entry())
1772 {
1773 elfcpp::Sym_write<size, big_endian> osym(ov);
1774
1775 gold_assert(isym.get_st_name() < strtab_size);
1776 const char* name = pnames + isym.get_st_name();
1777 osym.put_st_name(sympool->get_offset(name));
1778 osym.put_st_value(this->local_values_[i].value(this, 0));
1779 osym.put_st_size(isym.get_st_size());
1780 osym.put_st_info(isym.get_st_info());
1781 osym.put_st_other(isym.get_st_other());
1782 osym.put_st_shndx(st_shndx);
1783
1784 ov += sym_size;
1785 }
1786
1787 // Write the symbol to the output dynamic symbol table.
1788 if (lv.needs_output_dynsym_entry())
1789 {
1790 gold_assert(dyn_ov < dyn_oview + dyn_output_size);
1791 elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
1792
1793 gold_assert(isym.get_st_name() < strtab_size);
1794 const char* name = pnames + isym.get_st_name();
1795 osym.put_st_name(dynpool->get_offset(name));
1796 osym.put_st_value(this->local_values_[i].value(this, 0));
1797 osym.put_st_size(isym.get_st_size());
1798 osym.put_st_info(isym.get_st_info());
1799 osym.put_st_other(isym.get_st_other());
1800 osym.put_st_shndx(st_shndx);
1801
1802 dyn_ov += sym_size;
1803 }
1804 }
1805
1806
1807 if (output_size > 0)
1808 {
1809 gold_assert(ov - oview == output_size);
1810 of->write_output_view(this->local_symbol_offset_, output_size, oview);
1811 }
1812
1813 if (dyn_output_size > 0)
1814 {
1815 gold_assert(dyn_ov - dyn_oview == dyn_output_size);
1816 of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
1817 dyn_oview);
1818 }
1819 }
1820
1821 // Set *INFO to symbolic information about the offset OFFSET in the
1822 // section SHNDX. Return true if we found something, false if we
1823 // found nothing.
1824
1825 template<int size, bool big_endian>
1826 bool
1827 Sized_relobj<size, big_endian>::get_symbol_location_info(
1828 unsigned int shndx,
1829 off_t offset,
1830 Symbol_location_info* info)
1831 {
1832 if (this->symtab_shndx_ == 0)
1833 return false;
1834
1835 section_size_type symbols_size;
1836 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
1837 &symbols_size,
1838 false);
1839
1840 unsigned int symbol_names_shndx =
1841 this->adjust_shndx(this->section_link(this->symtab_shndx_));
1842 section_size_type names_size;
1843 const unsigned char* symbol_names_u =
1844 this->section_contents(symbol_names_shndx, &names_size, false);
1845 const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
1846
1847 const int sym_size = This::sym_size;
1848 const size_t count = symbols_size / sym_size;
1849
1850 const unsigned char* p = symbols;
1851 for (size_t i = 0; i < count; ++i, p += sym_size)
1852 {
1853 elfcpp::Sym<size, big_endian> sym(p);
1854
1855 if (sym.get_st_type() == elfcpp::STT_FILE)
1856 {
1857 if (sym.get_st_name() >= names_size)
1858 info->source_file = "(invalid)";
1859 else
1860 info->source_file = symbol_names + sym.get_st_name();
1861 continue;
1862 }
1863
1864 bool is_ordinary;
1865 unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1866 &is_ordinary);
1867 if (is_ordinary
1868 && st_shndx == shndx
1869 && static_cast<off_t>(sym.get_st_value()) <= offset
1870 && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
1871 > offset))
1872 {
1873 if (sym.get_st_name() > names_size)
1874 info->enclosing_symbol_name = "(invalid)";
1875 else
1876 {
1877 info->enclosing_symbol_name = symbol_names + sym.get_st_name();
1878 if (parameters->options().do_demangle())
1879 {
1880 char* demangled_name = cplus_demangle(
1881 info->enclosing_symbol_name.c_str(),
1882 DMGL_ANSI | DMGL_PARAMS);
1883 if (demangled_name != NULL)
1884 {
1885 info->enclosing_symbol_name.assign(demangled_name);
1886 free(demangled_name);
1887 }
1888 }
1889 }
1890 return true;
1891 }
1892 }
1893
1894 return false;
1895 }
1896
1897 // Look for a kept section corresponding to the given discarded section,
1898 // and return its output address. This is used only for relocations in
1899 // debugging sections. If we can't find the kept section, return 0.
1900
1901 template<int size, bool big_endian>
1902 typename Sized_relobj<size, big_endian>::Address
1903 Sized_relobj<size, big_endian>::map_to_kept_section(
1904 unsigned int shndx,
1905 bool* found) const
1906 {
1907 Kept_comdat_section *kept = this->get_kept_comdat_section(shndx);
1908 if (kept != NULL)
1909 {
1910 gold_assert(kept->object_ != NULL);
1911 *found = true;
1912 Output_section* os = kept->object_->output_section(kept->shndx_);
1913 Address offset = kept->object_->get_output_section_offset(kept->shndx_);
1914 if (os != NULL && offset != invalid_address)
1915 return os->address() + offset;
1916 }
1917 *found = false;
1918 return 0;
1919 }
1920
1921 // Get symbol counts.
1922
1923 template<int size, bool big_endian>
1924 void
1925 Sized_relobj<size, big_endian>::do_get_global_symbol_counts(
1926 const Symbol_table*,
1927 size_t* defined,
1928 size_t* used) const
1929 {
1930 *defined = this->defined_count_;
1931 size_t count = 0;
1932 for (Symbols::const_iterator p = this->symbols_.begin();
1933 p != this->symbols_.end();
1934 ++p)
1935 if (*p != NULL
1936 && (*p)->source() == Symbol::FROM_OBJECT
1937 && (*p)->object() == this
1938 && (*p)->is_defined())
1939 ++count;
1940 *used = count;
1941 }
1942
1943 // Input_objects methods.
1944
1945 // Add a regular relocatable object to the list. Return false if this
1946 // object should be ignored.
1947
1948 bool
1949 Input_objects::add_object(Object* obj)
1950 {
1951 // Set the global target from the first object file we recognize.
1952 Target* target = obj->target();
1953 if (!parameters->target_valid())
1954 set_parameters_target(target);
1955 else if (target != &parameters->target())
1956 {
1957 obj->error(_("incompatible target"));
1958 return false;
1959 }
1960
1961 // Print the filename if the -t/--trace option is selected.
1962 if (parameters->options().trace())
1963 gold_info("%s", obj->name().c_str());
1964
1965 if (!obj->is_dynamic())
1966 this->relobj_list_.push_back(static_cast<Relobj*>(obj));
1967 else
1968 {
1969 // See if this is a duplicate SONAME.
1970 Dynobj* dynobj = static_cast<Dynobj*>(obj);
1971 const char* soname = dynobj->soname();
1972
1973 std::pair<Unordered_set<std::string>::iterator, bool> ins =
1974 this->sonames_.insert(soname);
1975 if (!ins.second)
1976 {
1977 // We have already seen a dynamic object with this soname.
1978 return false;
1979 }
1980
1981 this->dynobj_list_.push_back(dynobj);
1982 }
1983
1984 // Add this object to the cross-referencer if requested.
1985 if (parameters->options().user_set_print_symbol_counts())
1986 {
1987 if (this->cref_ == NULL)
1988 this->cref_ = new Cref();
1989 this->cref_->add_object(obj);
1990 }
1991
1992 return true;
1993 }
1994
1995 // For each dynamic object, record whether we've seen all of its
1996 // explicit dependencies.
1997
1998 void
1999 Input_objects::check_dynamic_dependencies() const
2000 {
2001 for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2002 p != this->dynobj_list_.end();
2003 ++p)
2004 {
2005 const Dynobj::Needed& needed((*p)->needed());
2006 bool found_all = true;
2007 for (Dynobj::Needed::const_iterator pneeded = needed.begin();
2008 pneeded != needed.end();
2009 ++pneeded)
2010 {
2011 if (this->sonames_.find(*pneeded) == this->sonames_.end())
2012 {
2013 found_all = false;
2014 break;
2015 }
2016 }
2017 (*p)->set_has_unknown_needed_entries(!found_all);
2018 }
2019 }
2020
2021 // Start processing an archive.
2022
2023 void
2024 Input_objects::archive_start(Archive* archive)
2025 {
2026 if (parameters->options().user_set_print_symbol_counts())
2027 {
2028 if (this->cref_ == NULL)
2029 this->cref_ = new Cref();
2030 this->cref_->add_archive_start(archive);
2031 }
2032 }
2033
2034 // Stop processing an archive.
2035
2036 void
2037 Input_objects::archive_stop(Archive* archive)
2038 {
2039 if (parameters->options().user_set_print_symbol_counts())
2040 this->cref_->add_archive_stop(archive);
2041 }
2042
2043 // Print symbol counts
2044
2045 void
2046 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2047 {
2048 if (parameters->options().user_set_print_symbol_counts()
2049 && this->cref_ != NULL)
2050 this->cref_->print_symbol_counts(symtab);
2051 }
2052
2053 // Relocate_info methods.
2054
2055 // Return a string describing the location of a relocation. This is
2056 // only used in error messages.
2057
2058 template<int size, bool big_endian>
2059 std::string
2060 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2061 {
2062 // See if we can get line-number information from debugging sections.
2063 std::string filename;
2064 std::string file_and_lineno; // Better than filename-only, if available.
2065
2066 Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2067 // This will be "" if we failed to parse the debug info for any reason.
2068 file_and_lineno = line_info.addr2line(this->data_shndx, offset);
2069
2070 std::string ret(this->object->name());
2071 ret += ':';
2072 Symbol_location_info info;
2073 if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2074 {
2075 ret += " in function ";
2076 ret += info.enclosing_symbol_name;
2077 ret += ":";
2078 filename = info.source_file;
2079 }
2080
2081 if (!file_and_lineno.empty())
2082 ret += file_and_lineno;
2083 else
2084 {
2085 if (!filename.empty())
2086 ret += filename;
2087 ret += "(";
2088 ret += this->object->section_name(this->data_shndx);
2089 char buf[100];
2090 // Offsets into sections have to be positive.
2091 snprintf(buf, sizeof(buf), "+0x%lx", static_cast<long>(offset));
2092 ret += buf;
2093 ret += ")";
2094 }
2095 return ret;
2096 }
2097
2098 } // End namespace gold.
2099
2100 namespace
2101 {
2102
2103 using namespace gold;
2104
2105 // Read an ELF file with the header and return the appropriate
2106 // instance of Object.
2107
2108 template<int size, bool big_endian>
2109 Object*
2110 make_elf_sized_object(const std::string& name, Input_file* input_file,
2111 off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
2112 {
2113 int et = ehdr.get_e_type();
2114 if (et == elfcpp::ET_REL)
2115 {
2116 Sized_relobj<size, big_endian>* obj =
2117 new Sized_relobj<size, big_endian>(name, input_file, offset, ehdr);
2118 obj->setup(ehdr);
2119 return obj;
2120 }
2121 else if (et == elfcpp::ET_DYN)
2122 {
2123 Sized_dynobj<size, big_endian>* obj =
2124 new Sized_dynobj<size, big_endian>(name, input_file, offset, ehdr);
2125 obj->setup(ehdr);
2126 return obj;
2127 }
2128 else
2129 {
2130 gold_error(_("%s: unsupported ELF file type %d"),
2131 name.c_str(), et);
2132 return NULL;
2133 }
2134 }
2135
2136 } // End anonymous namespace.
2137
2138 namespace gold
2139 {
2140
2141 // Return whether INPUT_FILE is an ELF object.
2142
2143 bool
2144 is_elf_object(Input_file* input_file, off_t offset,
2145 const unsigned char** start, int *read_size)
2146 {
2147 off_t filesize = input_file->file().filesize();
2148 int want = elfcpp::Elf_sizes<64>::ehdr_size;
2149 if (filesize - offset < want)
2150 want = filesize - offset;
2151
2152 const unsigned char* p = input_file->file().get_view(offset, 0, want,
2153 true, false);
2154 *start = p;
2155 *read_size = want;
2156
2157 if (want < 4)
2158 return false;
2159
2160 static unsigned char elfmagic[4] =
2161 {
2162 elfcpp::ELFMAG0, elfcpp::ELFMAG1,
2163 elfcpp::ELFMAG2, elfcpp::ELFMAG3
2164 };
2165 return memcmp(p, elfmagic, 4) == 0;
2166 }
2167
2168 // Read an ELF file and return the appropriate instance of Object.
2169
2170 Object*
2171 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
2172 const unsigned char* p, section_offset_type bytes,
2173 bool* punconfigured)
2174 {
2175 if (punconfigured != NULL)
2176 *punconfigured = false;
2177
2178 if (bytes < elfcpp::EI_NIDENT)
2179 {
2180 gold_error(_("%s: ELF file too short"), name.c_str());
2181 return NULL;
2182 }
2183
2184 int v = p[elfcpp::EI_VERSION];
2185 if (v != elfcpp::EV_CURRENT)
2186 {
2187 if (v == elfcpp::EV_NONE)
2188 gold_error(_("%s: invalid ELF version 0"), name.c_str());
2189 else
2190 gold_error(_("%s: unsupported ELF version %d"), name.c_str(), v);
2191 return NULL;
2192 }
2193
2194 int c = p[elfcpp::EI_CLASS];
2195 if (c == elfcpp::ELFCLASSNONE)
2196 {
2197 gold_error(_("%s: invalid ELF class 0"), name.c_str());
2198 return NULL;
2199 }
2200 else if (c != elfcpp::ELFCLASS32
2201 && c != elfcpp::ELFCLASS64)
2202 {
2203 gold_error(_("%s: unsupported ELF class %d"), name.c_str(), c);
2204 return NULL;
2205 }
2206
2207 int d = p[elfcpp::EI_DATA];
2208 if (d == elfcpp::ELFDATANONE)
2209 {
2210 gold_error(_("%s: invalid ELF data encoding"), name.c_str());
2211 return NULL;
2212 }
2213 else if (d != elfcpp::ELFDATA2LSB
2214 && d != elfcpp::ELFDATA2MSB)
2215 {
2216 gold_error(_("%s: unsupported ELF data encoding %d"), name.c_str(), d);
2217 return NULL;
2218 }
2219
2220 bool big_endian = d == elfcpp::ELFDATA2MSB;
2221
2222 if (c == elfcpp::ELFCLASS32)
2223 {
2224 if (bytes < elfcpp::Elf_sizes<32>::ehdr_size)
2225 {
2226 gold_error(_("%s: ELF file too short"), name.c_str());
2227 return NULL;
2228 }
2229 if (big_endian)
2230 {
2231 #ifdef HAVE_TARGET_32_BIG
2232 elfcpp::Ehdr<32, true> ehdr(p);
2233 return make_elf_sized_object<32, true>(name, input_file,
2234 offset, ehdr);
2235 #else
2236 if (punconfigured != NULL)
2237 *punconfigured = true;
2238 else
2239 gold_error(_("%s: not configured to support "
2240 "32-bit big-endian object"),
2241 name.c_str());
2242 return NULL;
2243 #endif
2244 }
2245 else
2246 {
2247 #ifdef HAVE_TARGET_32_LITTLE
2248 elfcpp::Ehdr<32, false> ehdr(p);
2249 return make_elf_sized_object<32, false>(name, input_file,
2250 offset, ehdr);
2251 #else
2252 if (punconfigured != NULL)
2253 *punconfigured = true;
2254 else
2255 gold_error(_("%s: not configured to support "
2256 "32-bit little-endian object"),
2257 name.c_str());
2258 return NULL;
2259 #endif
2260 }
2261 }
2262 else
2263 {
2264 if (bytes < elfcpp::Elf_sizes<64>::ehdr_size)
2265 {
2266 gold_error(_("%s: ELF file too short"), name.c_str());
2267 return NULL;
2268 }
2269 if (big_endian)
2270 {
2271 #ifdef HAVE_TARGET_64_BIG
2272 elfcpp::Ehdr<64, true> ehdr(p);
2273 return make_elf_sized_object<64, true>(name, input_file,
2274 offset, ehdr);
2275 #else
2276 if (punconfigured != NULL)
2277 *punconfigured = true;
2278 else
2279 gold_error(_("%s: not configured to support "
2280 "64-bit big-endian object"),
2281 name.c_str());
2282 return NULL;
2283 #endif
2284 }
2285 else
2286 {
2287 #ifdef HAVE_TARGET_64_LITTLE
2288 elfcpp::Ehdr<64, false> ehdr(p);
2289 return make_elf_sized_object<64, false>(name, input_file,
2290 offset, ehdr);
2291 #else
2292 if (punconfigured != NULL)
2293 *punconfigured = true;
2294 else
2295 gold_error(_("%s: not configured to support "
2296 "64-bit little-endian object"),
2297 name.c_str());
2298 return NULL;
2299 #endif
2300 }
2301 }
2302 }
2303
2304 // Instantiate the templates we need.
2305
2306 #ifdef HAVE_TARGET_32_LITTLE
2307 template
2308 void
2309 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
2310 Read_symbols_data*);
2311 #endif
2312
2313 #ifdef HAVE_TARGET_32_BIG
2314 template
2315 void
2316 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
2317 Read_symbols_data*);
2318 #endif
2319
2320 #ifdef HAVE_TARGET_64_LITTLE
2321 template
2322 void
2323 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
2324 Read_symbols_data*);
2325 #endif
2326
2327 #ifdef HAVE_TARGET_64_BIG
2328 template
2329 void
2330 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
2331 Read_symbols_data*);
2332 #endif
2333
2334 #ifdef HAVE_TARGET_32_LITTLE
2335 template
2336 class Sized_relobj<32, false>;
2337 #endif
2338
2339 #ifdef HAVE_TARGET_32_BIG
2340 template
2341 class Sized_relobj<32, true>;
2342 #endif
2343
2344 #ifdef HAVE_TARGET_64_LITTLE
2345 template
2346 class Sized_relobj<64, false>;
2347 #endif
2348
2349 #ifdef HAVE_TARGET_64_BIG
2350 template
2351 class Sized_relobj<64, true>;
2352 #endif
2353
2354 #ifdef HAVE_TARGET_32_LITTLE
2355 template
2356 struct Relocate_info<32, false>;
2357 #endif
2358
2359 #ifdef HAVE_TARGET_32_BIG
2360 template
2361 struct Relocate_info<32, true>;
2362 #endif
2363
2364 #ifdef HAVE_TARGET_64_LITTLE
2365 template
2366 struct Relocate_info<64, false>;
2367 #endif
2368
2369 #ifdef HAVE_TARGET_64_BIG
2370 template
2371 struct Relocate_info<64, true>;
2372 #endif
2373
2374 } // End namespace gold.
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