1 // ehframe.cc -- handle exception frame sections for gold
2 
3 // Copyright (C) 2006-2016 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 <cstring>
26 #include <algorithm>
27 
28 #include "elfcpp.h"
29 #include "dwarf.h"
30 #include "symtab.h"
31 #include "reloc.h"
32 #include "ehframe.h"
33 
34 namespace gold
35 {
36 
37 // This file handles generation of the exception frame header that
38 // gcc's runtime support libraries use to find unwind information at
39 // runtime.  This file also handles discarding duplicate exception
40 // frame information.
41 
42 // The exception frame header starts with four bytes:
43 
44 // 0: The version number, currently 1.
45 
46 // 1: The encoding of the pointer to the exception frames.  This can
47 //    be any DWARF unwind encoding (DW_EH_PE_*).  It is normally a 4
48 //    byte PC relative offset (DW_EH_PE_pcrel | DW_EH_PE_sdata4).
49 
50 // 2: The encoding of the count of the number of FDE pointers in the
51 //    lookup table.  This can be any DWARF unwind encoding, and in
52 //    particular can be DW_EH_PE_omit if the count is omitted.  It is
53 //    normally a 4 byte unsigned count (DW_EH_PE_udata4).
54 
55 // 3: The encoding of the lookup table entries.  Currently gcc's
56 //    libraries will only support DW_EH_PE_datarel | DW_EH_PE_sdata4,
57 //    which means that the values are 4 byte offsets from the start of
58 //    the table.
59 
60 // The exception frame header is followed by a pointer to the contents
61 // of the exception frame section (.eh_frame).  This pointer is
62 // encoded as specified in the byte at offset 1 of the header (i.e.,
63 // it is normally a 4 byte PC relative offset).
64 
65 // If there is a lookup table, this is followed by the count of the
66 // number of FDE pointers, encoded as specified in the byte at offset
67 // 2 of the header (i.e., normally a 4 byte unsigned integer).
68 
69 // This is followed by the table, which should start at an 4-byte
70 // aligned address in memory.  Each entry in the table is 8 bytes.
71 // Each entry represents an FDE.  The first four bytes of each entry
72 // are an offset to the starting PC for the FDE.  The last four bytes
73 // of each entry are an offset to the FDE data.  The offsets are from
74 // the start of the exception frame header information.  The entries
75 // are in sorted order by starting PC.
76 
77 const int eh_frame_hdr_size = 4;
78 
79 // Construct the exception frame header.
80 
Eh_frame_hdr(Output_section * eh_frame_section,const Eh_frame * eh_frame_data)81 Eh_frame_hdr::Eh_frame_hdr(Output_section* eh_frame_section,
82 			   const Eh_frame* eh_frame_data)
83   : Output_section_data(4),
84     eh_frame_section_(eh_frame_section),
85     eh_frame_data_(eh_frame_data),
86     fde_offsets_(),
87     any_unrecognized_eh_frame_sections_(false)
88 {
89 }
90 
91 // Set the size of the exception frame header.
92 
93 void
set_final_data_size()94 Eh_frame_hdr::set_final_data_size()
95 {
96   unsigned int data_size = eh_frame_hdr_size + 4;
97   if (!this->any_unrecognized_eh_frame_sections_)
98     {
99       unsigned int fde_count = this->eh_frame_data_->fde_count();
100       if (fde_count != 0)
101 	data_size += 4 + 8 * fde_count;
102       this->fde_offsets_.reserve(fde_count);
103     }
104   this->set_data_size(data_size);
105 }
106 
107 // Write the data to the file.
108 
109 void
do_write(Output_file * of)110 Eh_frame_hdr::do_write(Output_file* of)
111 {
112   switch (parameters->size_and_endianness())
113     {
114 #ifdef HAVE_TARGET_32_LITTLE
115     case Parameters::TARGET_32_LITTLE:
116       this->do_sized_write<32, false>(of);
117       break;
118 #endif
119 #ifdef HAVE_TARGET_32_BIG
120     case Parameters::TARGET_32_BIG:
121       this->do_sized_write<32, true>(of);
122       break;
123 #endif
124 #ifdef HAVE_TARGET_64_LITTLE
125     case Parameters::TARGET_64_LITTLE:
126       this->do_sized_write<64, false>(of);
127       break;
128 #endif
129 #ifdef HAVE_TARGET_64_BIG
130     case Parameters::TARGET_64_BIG:
131       this->do_sized_write<64, true>(of);
132       break;
133 #endif
134     default:
135       gold_unreachable();
136     }
137 }
138 
139 // Write the data to the file with the right endianness.
140 
141 template<int size, bool big_endian>
142 void
do_sized_write(Output_file * of)143 Eh_frame_hdr::do_sized_write(Output_file* of)
144 {
145   const off_t off = this->offset();
146   const off_t oview_size = this->data_size();
147   unsigned char* const oview = of->get_output_view(off, oview_size);
148 
149   // Version number.
150   oview[0] = 1;
151 
152   // Write out a 4 byte PC relative offset to the address of the
153   // .eh_frame section.
154   oview[1] = elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4;
155   uint64_t eh_frame_address = this->eh_frame_section_->address();
156   uint64_t eh_frame_hdr_address = this->address();
157   uint64_t eh_frame_offset = (eh_frame_address -
158 			      (eh_frame_hdr_address + 4));
159   elfcpp::Swap<32, big_endian>::writeval(oview + 4, eh_frame_offset);
160 
161   if (this->any_unrecognized_eh_frame_sections_
162       || this->fde_offsets_.empty())
163     {
164       // There are no FDEs, or we didn't recognize the format of the
165       // some of the .eh_frame sections, so we can't write out the
166       // sorted table.
167       oview[2] = elfcpp::DW_EH_PE_omit;
168       oview[3] = elfcpp::DW_EH_PE_omit;
169 
170       gold_assert(oview_size == 8);
171     }
172   else
173     {
174       oview[2] = elfcpp::DW_EH_PE_udata4;
175       oview[3] = elfcpp::DW_EH_PE_datarel | elfcpp::DW_EH_PE_sdata4;
176 
177       elfcpp::Swap<32, big_endian>::writeval(oview + 8,
178 					     this->fde_offsets_.size());
179 
180       // We have the offsets of the FDEs in the .eh_frame section.  We
181       // couldn't easily get the PC values before, as they depend on
182       // relocations which are, of course, target specific.  This code
183       // is run after all those relocations have been applied to the
184       // output file.  Here we read the output file again to find the
185       // PC values.  Then we sort the list and write it out.
186 
187       Fde_addresses<size> fde_addresses(this->fde_offsets_.size());
188       this->get_fde_addresses<size, big_endian>(of, &this->fde_offsets_,
189 						&fde_addresses);
190 
191       std::sort(fde_addresses.begin(), fde_addresses.end(),
192 		Fde_address_compare<size>());
193 
194       typename elfcpp::Elf_types<size>::Elf_Addr output_address;
195       output_address = this->address();
196 
197       unsigned char* pfde = oview + 12;
198       for (typename Fde_addresses<size>::iterator p = fde_addresses.begin();
199 	   p != fde_addresses.end();
200 	   ++p)
201 	{
202 	  elfcpp::Swap<32, big_endian>::writeval(pfde,
203 						 p->first - output_address);
204 	  elfcpp::Swap<32, big_endian>::writeval(pfde + 4,
205 						 p->second - output_address);
206 	  pfde += 8;
207 	}
208 
209       gold_assert(pfde - oview == oview_size);
210     }
211 
212   of->write_output_view(off, oview_size, oview);
213 }
214 
215 // Given the offset FDE_OFFSET of an FDE in the .eh_frame section, and
216 // the contents of the .eh_frame section EH_FRAME_CONTENTS, where the
217 // FDE's encoding is FDE_ENCODING, return the output address of the
218 // FDE's PC.
219 
220 template<int size, bool big_endian>
221 typename elfcpp::Elf_types<size>::Elf_Addr
get_fde_pc(typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address,const unsigned char * eh_frame_contents,section_offset_type fde_offset,unsigned char fde_encoding)222 Eh_frame_hdr::get_fde_pc(
223     typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address,
224     const unsigned char* eh_frame_contents,
225     section_offset_type fde_offset,
226     unsigned char fde_encoding)
227 {
228   // The FDE starts with a 4 byte length and a 4 byte offset to the
229   // CIE.  The PC follows.
230   const unsigned char* p = eh_frame_contents + fde_offset + 8;
231 
232   typename elfcpp::Elf_types<size>::Elf_Addr pc;
233   bool is_signed = (fde_encoding & elfcpp::DW_EH_PE_signed) != 0;
234   int pc_size = fde_encoding & 7;
235   if (pc_size == elfcpp::DW_EH_PE_absptr)
236     {
237       if (size == 32)
238 	pc_size = elfcpp::DW_EH_PE_udata4;
239       else if (size == 64)
240 	pc_size = elfcpp::DW_EH_PE_udata8;
241       else
242 	gold_unreachable();
243     }
244 
245   switch (pc_size)
246     {
247     case elfcpp::DW_EH_PE_udata2:
248       pc = elfcpp::Swap<16, big_endian>::readval(p);
249       if (is_signed)
250 	pc = (pc ^ 0x8000) - 0x8000;
251       break;
252 
253     case elfcpp::DW_EH_PE_udata4:
254       pc = elfcpp::Swap<32, big_endian>::readval(p);
255       if (size > 32 && is_signed)
256 	pc = (pc ^ 0x80000000) - 0x80000000;
257       break;
258 
259     case elfcpp::DW_EH_PE_udata8:
260       gold_assert(size == 64);
261       pc = elfcpp::Swap_unaligned<64, big_endian>::readval(p);
262       break;
263 
264     default:
265       // All other cases were rejected in Eh_frame::read_cie.
266       gold_unreachable();
267     }
268 
269   switch (fde_encoding & 0x70)
270     {
271     case 0:
272       break;
273 
274     case elfcpp::DW_EH_PE_pcrel:
275       pc += eh_frame_address + fde_offset + 8;
276       break;
277 
278     case elfcpp::DW_EH_PE_datarel:
279       pc += parameters->target().ehframe_datarel_base();
280       break;
281 
282     default:
283       // If other cases arise, then we have to handle them, or we have
284       // to reject them by returning false in Eh_frame::read_cie.
285       gold_unreachable();
286     }
287 
288   gold_assert((fde_encoding & elfcpp::DW_EH_PE_indirect) == 0);
289 
290   return pc;
291 }
292 
293 // Given an array of FDE offsets in the .eh_frame section, return an
294 // array of offsets from the exception frame header to the FDE's
295 // output PC and to the output address of the FDE itself.  We get the
296 // FDE's PC by actually looking in the .eh_frame section we just wrote
297 // to the output file.
298 
299 template<int size, bool big_endian>
300 void
get_fde_addresses(Output_file * of,const Fde_offsets * fde_offsets,Fde_addresses<size> * fde_addresses)301 Eh_frame_hdr::get_fde_addresses(Output_file* of,
302 				const Fde_offsets* fde_offsets,
303 				Fde_addresses<size>* fde_addresses)
304 {
305   typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address;
306   eh_frame_address = this->eh_frame_section_->address();
307   off_t eh_frame_offset = this->eh_frame_section_->offset();
308   off_t eh_frame_size = this->eh_frame_section_->data_size();
309   const unsigned char* eh_frame_contents = of->get_input_view(eh_frame_offset,
310 							      eh_frame_size);
311 
312   for (Fde_offsets::const_iterator p = fde_offsets->begin();
313        p != fde_offsets->end();
314        ++p)
315     {
316       typename elfcpp::Elf_types<size>::Elf_Addr fde_pc;
317       fde_pc = this->get_fde_pc<size, big_endian>(eh_frame_address,
318 						  eh_frame_contents,
319 						  p->first, p->second);
320       fde_addresses->push_back(fde_pc, eh_frame_address + p->first);
321     }
322 
323   of->free_input_view(eh_frame_offset, eh_frame_size, eh_frame_contents);
324 }
325 
326 // Class Fde.
327 
328 // Write the FDE to OVIEW starting at OFFSET.  CIE_OFFSET is the
329 // offset of the CIE in OVIEW.  OUTPUT_OFFSET is the offset of the
330 // Eh_frame section within the output section.  FDE_ENCODING is the
331 // encoding, from the CIE.  ADDRALIGN is the required alignment.
332 // ADDRESS is the virtual address of OVIEW.  Record the FDE pc for
333 // EH_FRAME_HDR.  Return the new offset.
334 
335 template<int size, bool big_endian>
336 section_offset_type
write(unsigned char * oview,section_offset_type output_offset,section_offset_type offset,uint64_t address,unsigned int addralign,section_offset_type cie_offset,unsigned char fde_encoding,Eh_frame_hdr * eh_frame_hdr)337 Fde::write(unsigned char* oview, section_offset_type output_offset,
338 	   section_offset_type offset, uint64_t address, unsigned int addralign,
339 	   section_offset_type cie_offset, unsigned char fde_encoding,
340 	   Eh_frame_hdr* eh_frame_hdr)
341 {
342   gold_assert((offset & (addralign - 1)) == 0);
343 
344   size_t length = this->contents_.length();
345 
346   // We add 8 when getting the aligned length to account for the
347   // length word and the CIE offset.
348   size_t aligned_full_length = align_address(length + 8, addralign);
349 
350   // Write the length of the FDE as a 32-bit word.  The length word
351   // does not include the four bytes of the length word itself, but it
352   // does include the offset to the CIE.
353   elfcpp::Swap<32, big_endian>::writeval(oview + offset,
354                                          aligned_full_length - 4);
355 
356   // Write the offset to the CIE as a 32-bit word.  This is the
357   // difference between the address of the offset word itself and the
358   // CIE address.
359   elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4,
360 					 offset + 4 - cie_offset);
361 
362   // Copy the rest of the FDE.  Note that this is run before
363   // relocation processing is done on this section, so the relocations
364   // will later be applied to the FDE data.
365   memcpy(oview + offset + 8, this->contents_.data(), length);
366 
367   // If this FDE is associated with a PLT, fill in the PLT's address
368   // and size.
369   if (this->object_ == NULL)
370     {
371       gold_assert(memcmp(oview + offset + 8, "\0\0\0\0\0\0\0\0", 8) == 0);
372       uint64_t paddress;
373       off_t psize;
374       parameters->target().plt_fde_location(this->u_.from_linker.plt,
375 					    oview + offset + 8,
376 					    &paddress, &psize);
377       uint64_t poffset = paddress - (address + offset + 8);
378       int32_t spoffset = static_cast<int32_t>(poffset);
379       uint32_t upsize = static_cast<uint32_t>(psize);
380       if (static_cast<uint64_t>(static_cast<int64_t>(spoffset)) != poffset
381 	  || static_cast<off_t>(upsize) != psize)
382 	gold_warning(_("overflow in PLT unwind data; "
383 		       "unwinding through PLT may fail"));
384       elfcpp::Swap<32, big_endian>::writeval(oview + offset + 8, spoffset);
385       elfcpp::Swap<32, big_endian>::writeval(oview + offset + 12, upsize);
386     }
387 
388   if (aligned_full_length > length + 8)
389     memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
390 
391   // Tell the exception frame header about this FDE.
392   if (eh_frame_hdr != NULL)
393     eh_frame_hdr->record_fde(output_offset + offset, fde_encoding);
394 
395   return offset + aligned_full_length;
396 }
397 
398 // Class Cie.
399 
400 // Destructor.
401 
~Cie()402 Cie::~Cie()
403 {
404   for (std::vector<Fde*>::iterator p = this->fdes_.begin();
405        p != this->fdes_.end();
406        ++p)
407     delete *p;
408 }
409 
410 // Set the output offset of a CIE.  Return the new output offset.
411 
412 section_offset_type
set_output_offset(section_offset_type output_offset,unsigned int addralign,Output_section_data * output_data)413 Cie::set_output_offset(section_offset_type output_offset,
414 		       unsigned int addralign,
415 		       Output_section_data *output_data)
416 {
417   size_t length = this->contents_.length();
418 
419   // Add 4 for length and 4 for zero CIE identifier tag.
420   length += 8;
421 
422   if (this->object_ != NULL)
423     {
424       // Add a mapping so that relocations are applied correctly.
425       this->object_->add_merge_mapping(output_data, this->shndx_,
426                                        this->input_offset_, length,
427                                        output_offset);
428     }
429 
430   length = align_address(length, addralign);
431 
432   for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
433        p != this->fdes_.end();
434        ++p)
435     {
436       (*p)->add_mapping(output_offset + length, output_data);
437 
438       size_t fde_length = (*p)->length();
439       fde_length = align_address(fde_length, addralign);
440       length += fde_length;
441     }
442 
443   return output_offset + length;
444 }
445 
446 // Write the CIE to OVIEW starting at OFFSET.  OUTPUT_OFFSET is the
447 // offset of the Eh_frame section within the output section.  Round up
448 // the bytes to ADDRALIGN.  ADDRESS is the virtual address of OVIEW.
449 // EH_FRAME_HDR is the exception frame header for FDE recording.
450 // POST_FDES stashes FDEs created after mappings were done, for later
451 // writing.  Return the new offset.
452 
453 template<int size, bool big_endian>
454 section_offset_type
write(unsigned char * oview,section_offset_type output_offset,section_offset_type offset,uint64_t address,unsigned int addralign,Eh_frame_hdr * eh_frame_hdr,Post_fdes * post_fdes)455 Cie::write(unsigned char* oview, section_offset_type output_offset,
456 	   section_offset_type offset, uint64_t address,
457 	   unsigned int addralign, Eh_frame_hdr* eh_frame_hdr,
458 	   Post_fdes* post_fdes)
459 {
460   gold_assert((offset & (addralign - 1)) == 0);
461 
462   section_offset_type cie_offset = offset;
463 
464   size_t length = this->contents_.length();
465 
466   // We add 8 when getting the aligned length to account for the
467   // length word and the CIE tag.
468   size_t aligned_full_length = align_address(length + 8, addralign);
469 
470   // Write the length of the CIE as a 32-bit word.  The length word
471   // does not include the four bytes of the length word itself.
472   elfcpp::Swap<32, big_endian>::writeval(oview + offset,
473                                          aligned_full_length - 4);
474 
475   // Write the tag which marks this as a CIE: a 32-bit zero.
476   elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4, 0);
477 
478   // Write out the CIE data.
479   memcpy(oview + offset + 8, this->contents_.data(), length);
480 
481   if (aligned_full_length > length + 8)
482     memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
483 
484   offset += aligned_full_length;
485 
486   // Write out the associated FDEs.
487   unsigned char fde_encoding = this->fde_encoding_;
488   for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
489        p != this->fdes_.end();
490        ++p)
491     {
492       if ((*p)->post_map())
493 	post_fdes->push_back(Post_fde(*p, cie_offset, fde_encoding));
494       else
495 	offset = (*p)->write<size, big_endian>(oview, output_offset, offset,
496 					       address, addralign, cie_offset,
497 					       fde_encoding, eh_frame_hdr);
498     }
499 
500   return offset;
501 }
502 
503 // We track all the CIEs we see, and merge them when possible.  This
504 // works because each FDE holds an offset to the relevant CIE: we
505 // rewrite the FDEs to point to the merged CIE.  This is worthwhile
506 // because in a typical C++ program many FDEs in many different object
507 // files will use the same CIE.
508 
509 // An equality operator for Cie.
510 
511 bool
operator ==(const Cie & cie1,const Cie & cie2)512 operator==(const Cie& cie1, const Cie& cie2)
513 {
514   return (cie1.personality_name_ == cie2.personality_name_
515 	  && cie1.contents_ == cie2.contents_);
516 }
517 
518 // A less-than operator for Cie.
519 
520 bool
operator <(const Cie & cie1,const Cie & cie2)521 operator<(const Cie& cie1, const Cie& cie2)
522 {
523   if (cie1.personality_name_ != cie2.personality_name_)
524     return cie1.personality_name_ < cie2.personality_name_;
525   return cie1.contents_ < cie2.contents_;
526 }
527 
528 // Class Eh_frame.
529 
Eh_frame()530 Eh_frame::Eh_frame()
531   : Output_section_data(Output_data::default_alignment()),
532     eh_frame_hdr_(NULL),
533     cie_offsets_(),
534     unmergeable_cie_offsets_(),
535     mappings_are_done_(false),
536     final_data_size_(0)
537 {
538 }
539 
540 // Skip an LEB128, updating *PP to point to the next character.
541 // Return false if we ran off the end of the string.
542 
543 bool
skip_leb128(const unsigned char ** pp,const unsigned char * pend)544 Eh_frame::skip_leb128(const unsigned char** pp, const unsigned char* pend)
545 {
546   const unsigned char* p;
547   for (p = *pp; p < pend; ++p)
548     {
549       if ((*p & 0x80) == 0)
550 	{
551 	  *pp = p + 1;
552 	  return true;
553 	}
554     }
555   return false;
556 }
557 
558 // Add input section SHNDX in OBJECT to an exception frame section.
559 // SYMBOLS is the contents of the symbol table section (size
560 // SYMBOLS_SIZE), SYMBOL_NAMES is the symbol names section (size
561 // SYMBOL_NAMES_SIZE).  RELOC_SHNDX is the index of a relocation
562 // section applying to SHNDX, or 0 if none, or -1U if more than one.
563 // RELOC_TYPE is the type of the reloc section if there is one, either
564 // SHT_REL or SHT_RELA.  We try to parse the input exception frame
565 // data into our data structures.  If we can't do it, we return false
566 // to mean that the section should be handled as a normal input
567 // section.
568 
569 template<int size, bool big_endian>
570 Eh_frame::Eh_frame_section_disposition
add_ehframe_input_section(Sized_relobj_file<size,big_endian> * object,const unsigned char * symbols,section_size_type symbols_size,const unsigned char * symbol_names,section_size_type symbol_names_size,unsigned int shndx,unsigned int reloc_shndx,unsigned int reloc_type)571 Eh_frame::add_ehframe_input_section(
572     Sized_relobj_file<size, big_endian>* object,
573     const unsigned char* symbols,
574     section_size_type symbols_size,
575     const unsigned char* symbol_names,
576     section_size_type symbol_names_size,
577     unsigned int shndx,
578     unsigned int reloc_shndx,
579     unsigned int reloc_type)
580 {
581   // Get the section contents.
582   section_size_type contents_len;
583   const unsigned char* pcontents = object->section_contents(shndx,
584 							    &contents_len,
585 							    false);
586   if (contents_len == 0)
587     return EH_EMPTY_SECTION;
588 
589   // If this is the marker section for the end of the data, then
590   // return false to force it to be handled as an ordinary input
591   // section.  If we don't do this, we won't correctly handle the case
592   // of unrecognized .eh_frame sections.
593   if (contents_len == 4
594       && elfcpp::Swap<32, big_endian>::readval(pcontents) == 0)
595     return EH_END_MARKER_SECTION;
596 
597   New_cies new_cies;
598   if (!this->do_add_ehframe_input_section(object, symbols, symbols_size,
599 					  symbol_names, symbol_names_size,
600 					  shndx, reloc_shndx,
601 					  reloc_type, pcontents,
602 					  contents_len, &new_cies))
603     {
604       if (this->eh_frame_hdr_ != NULL)
605 	this->eh_frame_hdr_->found_unrecognized_eh_frame_section();
606 
607       for (New_cies::iterator p = new_cies.begin();
608 	   p != new_cies.end();
609 	   ++p)
610 	delete p->first;
611 
612       return EH_UNRECOGNIZED_SECTION;
613     }
614 
615   // Now that we know we are using this section, record any new CIEs
616   // that we found.
617   for (New_cies::const_iterator p = new_cies.begin();
618        p != new_cies.end();
619        ++p)
620     {
621       if (p->second)
622 	this->cie_offsets_.insert(p->first);
623       else
624 	this->unmergeable_cie_offsets_.push_back(p->first);
625     }
626 
627   return EH_OPTIMIZABLE_SECTION;
628 }
629 
630 // The bulk of the implementation of add_ehframe_input_section.
631 
632 template<int size, bool big_endian>
633 bool
do_add_ehframe_input_section(Sized_relobj_file<size,big_endian> * object,const unsigned char * symbols,section_size_type symbols_size,const unsigned char * symbol_names,section_size_type symbol_names_size,unsigned int shndx,unsigned int reloc_shndx,unsigned int reloc_type,const unsigned char * pcontents,section_size_type contents_len,New_cies * new_cies)634 Eh_frame::do_add_ehframe_input_section(
635     Sized_relobj_file<size, big_endian>* object,
636     const unsigned char* symbols,
637     section_size_type symbols_size,
638     const unsigned char* symbol_names,
639     section_size_type symbol_names_size,
640     unsigned int shndx,
641     unsigned int reloc_shndx,
642     unsigned int reloc_type,
643     const unsigned char* pcontents,
644     section_size_type contents_len,
645     New_cies* new_cies)
646 {
647   Track_relocs<size, big_endian> relocs;
648 
649   const unsigned char* p = pcontents;
650   const unsigned char* pend = p + contents_len;
651 
652   // Get the contents of the reloc section if any.
653   if (!relocs.initialize(object, reloc_shndx, reloc_type))
654     return false;
655 
656   // Keep track of which CIEs are at which offsets.
657   Offsets_to_cie cies;
658 
659   while (p < pend)
660     {
661       if (pend - p < 4)
662 	return false;
663 
664       // There shouldn't be any relocations here.
665       if (relocs.advance(p + 4 - pcontents) > 0)
666 	return false;
667 
668       unsigned int len = elfcpp::Swap<32, big_endian>::readval(p);
669       p += 4;
670       if (len == 0)
671 	{
672 	  // We should only find a zero-length entry at the end of the
673 	  // section.
674 	  if (p < pend)
675 	    return false;
676 	  break;
677 	}
678       // We don't support a 64-bit .eh_frame.
679       if (len == 0xffffffff)
680 	return false;
681       if (static_cast<unsigned int>(pend - p) < len)
682 	return false;
683 
684       const unsigned char* const pentend = p + len;
685 
686       if (pend - p < 4)
687 	return false;
688       if (relocs.advance(p + 4 - pcontents) > 0)
689 	return false;
690 
691       unsigned int id = elfcpp::Swap<32, big_endian>::readval(p);
692       p += 4;
693 
694       if (id == 0)
695 	{
696 	  // CIE.
697 	  if (!this->read_cie(object, shndx, symbols, symbols_size,
698 			      symbol_names, symbol_names_size,
699 			      pcontents, p, pentend, &relocs, &cies,
700 			      new_cies))
701 	    return false;
702 	}
703       else
704 	{
705 	  // FDE.
706 	  if (!this->read_fde(object, shndx, symbols, symbols_size,
707 			      pcontents, id, p, pentend, &relocs, &cies))
708 	    return false;
709 	}
710 
711       p = pentend;
712     }
713 
714   return true;
715 }
716 
717 // Read a CIE.  Return false if we can't parse the information.
718 
719 template<int size, bool big_endian>
720 bool
read_cie(Sized_relobj_file<size,big_endian> * object,unsigned int shndx,const unsigned char * symbols,section_size_type symbols_size,const unsigned char * symbol_names,section_size_type symbol_names_size,const unsigned char * pcontents,const unsigned char * pcie,const unsigned char * pcieend,Track_relocs<size,big_endian> * relocs,Offsets_to_cie * cies,New_cies * new_cies)721 Eh_frame::read_cie(Sized_relobj_file<size, big_endian>* object,
722 		   unsigned int shndx,
723 		   const unsigned char* symbols,
724 		   section_size_type symbols_size,
725 		   const unsigned char* symbol_names,
726 		   section_size_type symbol_names_size,
727 		   const unsigned char* pcontents,
728 		   const unsigned char* pcie,
729 		   const unsigned char* pcieend,
730 		   Track_relocs<size, big_endian>* relocs,
731 		   Offsets_to_cie* cies,
732 		   New_cies* new_cies)
733 {
734   bool mergeable = true;
735 
736   // We need to find the personality routine if there is one, since we
737   // can only merge CIEs which use the same routine.  We also need to
738   // find the FDE encoding if there is one, so that we can read the PC
739   // from the FDE.
740 
741   const unsigned char* p = pcie;
742 
743   if (pcieend - p < 1)
744     return false;
745   unsigned char version = *p++;
746   if (version != 1 && version != 3)
747     return false;
748 
749   const unsigned char* paug = p;
750   const void* paugendv = memchr(p, '\0', pcieend - p);
751   const unsigned char* paugend = static_cast<const unsigned char*>(paugendv);
752   if (paugend == NULL)
753     return false;
754   p = paugend + 1;
755 
756   if (paug[0] == 'e' && paug[1] == 'h')
757     {
758       // This is a CIE from gcc before version 3.0.  We can't merge
759       // these.  We can still read the FDEs.
760       mergeable = false;
761       paug += 2;
762       if (*paug != '\0')
763 	return false;
764       if (pcieend - p < size / 8)
765 	return false;
766       p += size / 8;
767     }
768 
769   // Skip the code alignment.
770   if (!skip_leb128(&p, pcieend))
771     return false;
772 
773   // Skip the data alignment.
774   if (!skip_leb128(&p, pcieend))
775     return false;
776 
777   // Skip the return column.
778   if (version == 1)
779     {
780       if (pcieend - p < 1)
781 	return false;
782       ++p;
783     }
784   else
785     {
786       if (!skip_leb128(&p, pcieend))
787 	return false;
788     }
789 
790   if (*paug == 'z')
791     {
792       ++paug;
793       // Skip the augmentation size.
794       if (!skip_leb128(&p, pcieend))
795 	return false;
796     }
797 
798   unsigned char fde_encoding = elfcpp::DW_EH_PE_absptr;
799   int per_offset = -1;
800   while (*paug != '\0')
801     {
802       switch (*paug)
803 	{
804 	case 'L': // LSDA encoding.
805 	  if (pcieend - p < 1)
806 	    return false;
807 	  ++p;
808 	  break;
809 
810 	case 'R': // FDE encoding.
811 	  if (pcieend - p < 1)
812 	    return false;
813 	  fde_encoding = *p;
814 	  switch (fde_encoding & 7)
815 	    {
816 	    case elfcpp::DW_EH_PE_absptr:
817 	    case elfcpp::DW_EH_PE_udata2:
818 	    case elfcpp::DW_EH_PE_udata4:
819 	    case elfcpp::DW_EH_PE_udata8:
820 	      break;
821 	    default:
822 	      // We don't expect to see any other cases here, and
823 	      // we're not prepared to handle them.
824 	      return false;
825 	    }
826 	  ++p;
827 	  break;
828 
829 	case 'S':
830 	  break;
831 
832 	case 'P':
833 	  // Personality encoding.
834 	  {
835 	    if (pcieend - p < 1)
836 	      return false;
837 	    unsigned char per_encoding = *p;
838 	    ++p;
839 
840 	    if ((per_encoding & 0x60) == 0x60)
841 	      return false;
842 	    unsigned int per_width;
843 	    switch (per_encoding & 7)
844 	      {
845 	      case elfcpp::DW_EH_PE_udata2:
846 		per_width = 2;
847 		break;
848 	      case elfcpp::DW_EH_PE_udata4:
849 		per_width = 4;
850 		break;
851 	      case elfcpp::DW_EH_PE_udata8:
852 		per_width = 8;
853 		break;
854 	      case elfcpp::DW_EH_PE_absptr:
855 		per_width = size / 8;
856 		break;
857 	      default:
858 		return false;
859 	      }
860 
861 	    if ((per_encoding & 0xf0) == elfcpp::DW_EH_PE_aligned)
862 	      {
863 		unsigned int len = p - pcie;
864 		len += per_width - 1;
865 		len &= ~ (per_width - 1);
866 		if (static_cast<unsigned int>(pcieend - p) < len)
867 		  return false;
868 		p += len;
869 	      }
870 
871 	    per_offset = p - pcontents;
872 
873 	    if (static_cast<unsigned int>(pcieend - p) < per_width)
874 	      return false;
875 	    p += per_width;
876 	  }
877 	  break;
878 
879 	default:
880 	  return false;
881 	}
882 
883       ++paug;
884     }
885 
886   const char* personality_name = "";
887   if (per_offset != -1)
888     {
889       if (relocs->advance(per_offset) > 0)
890 	return false;
891       if (relocs->next_offset() != per_offset)
892 	return false;
893 
894       unsigned int personality_symndx = relocs->next_symndx();
895       if (personality_symndx == -1U)
896 	return false;
897 
898       if (personality_symndx < object->local_symbol_count())
899 	{
900 	  // We can only merge this CIE if the personality routine is
901 	  // a global symbol.  We can still read the FDEs.
902 	  mergeable = false;
903 	}
904       else
905 	{
906 	  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
907 	  if (personality_symndx >= symbols_size / sym_size)
908 	    return false;
909 	  elfcpp::Sym<size, big_endian> sym(symbols
910 					    + (personality_symndx * sym_size));
911 	  unsigned int name_offset = sym.get_st_name();
912 	  if (name_offset >= symbol_names_size)
913 	    return false;
914 	  personality_name = (reinterpret_cast<const char*>(symbol_names)
915 			      + name_offset);
916 	}
917 
918       int r = relocs->advance(per_offset + 1);
919       gold_assert(r == 1);
920     }
921 
922   if (relocs->advance(pcieend - pcontents) > 0)
923     return false;
924 
925   Cie cie(object, shndx, (pcie - 8) - pcontents, fde_encoding,
926 	  personality_name, pcie, pcieend - pcie);
927   Cie* cie_pointer = NULL;
928   if (mergeable)
929     {
930       Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
931       if (find_cie != this->cie_offsets_.end())
932 	cie_pointer = *find_cie;
933       else
934 	{
935 	  // See if we already saw this CIE in this object file.
936 	  for (New_cies::const_iterator pc = new_cies->begin();
937 	       pc != new_cies->end();
938 	       ++pc)
939 	    {
940 	      if (*(pc->first) == cie)
941 		{
942 		  cie_pointer = pc->first;
943 		  break;
944 		}
945 	    }
946 	}
947     }
948 
949   if (cie_pointer == NULL)
950     {
951       cie_pointer = new Cie(cie);
952       new_cies->push_back(std::make_pair(cie_pointer, mergeable));
953     }
954   else
955     {
956       // We are deleting this CIE.  Record that in our mapping from
957       // input sections to the output section.  At this point we don't
958       // know for sure that we are doing a special mapping for this
959       // input section, but that's OK--if we don't do a special
960       // mapping, nobody will ever ask for the mapping we add here.
961       object->add_merge_mapping(this, shndx, (pcie - 8) - pcontents,
962                                 pcieend - (pcie - 8), -1);
963     }
964 
965   // Record this CIE plus the offset in the input section.
966   cies->insert(std::make_pair(pcie - pcontents, cie_pointer));
967 
968   return true;
969 }
970 
971 // Read an FDE.  Return false if we can't parse the information.
972 
973 template<int size, bool big_endian>
974 bool
read_fde(Sized_relobj_file<size,big_endian> * object,unsigned int shndx,const unsigned char * symbols,section_size_type symbols_size,const unsigned char * pcontents,unsigned int offset,const unsigned char * pfde,const unsigned char * pfdeend,Track_relocs<size,big_endian> * relocs,Offsets_to_cie * cies)975 Eh_frame::read_fde(Sized_relobj_file<size, big_endian>* object,
976 		   unsigned int shndx,
977 		   const unsigned char* symbols,
978 		   section_size_type symbols_size,
979 		   const unsigned char* pcontents,
980 		   unsigned int offset,
981 		   const unsigned char* pfde,
982 		   const unsigned char* pfdeend,
983 		   Track_relocs<size, big_endian>* relocs,
984 		   Offsets_to_cie* cies)
985 {
986   // OFFSET is the distance between the 4 bytes before PFDE to the
987   // start of the CIE.  The offset we recorded for the CIE is 8 bytes
988   // after the start of the CIE--after the length and the zero tag.
989   unsigned int cie_offset = (pfde - 4 - pcontents) - offset + 8;
990   Offsets_to_cie::const_iterator pcie = cies->find(cie_offset);
991   if (pcie == cies->end())
992     return false;
993   Cie* cie = pcie->second;
994 
995   int pc_size = 0;
996   switch (cie->fde_encoding() & 7)
997     {
998     case elfcpp::DW_EH_PE_udata2:
999       pc_size = 2;
1000       break;
1001     case elfcpp::DW_EH_PE_udata4:
1002       pc_size = 4;
1003       break;
1004     case elfcpp::DW_EH_PE_udata8:
1005       gold_assert(size == 64);
1006       pc_size = 8;
1007       break;
1008     case elfcpp::DW_EH_PE_absptr:
1009       pc_size = size == 32 ? 4 : 8;
1010       break;
1011     default:
1012       // All other cases were rejected in Eh_frame::read_cie.
1013       gold_unreachable();
1014     }
1015 
1016   // The FDE should start with a reloc to the start of the code which
1017   // it describes.
1018   if (relocs->advance(pfde - pcontents) > 0)
1019     return false;
1020   if (relocs->next_offset() != pfde - pcontents)
1021     {
1022       // In an object produced by a relocatable link, gold may have
1023       // discarded a COMDAT group in the previous link, but not the
1024       // corresponding FDEs. In that case, gold will have discarded
1025       // the relocations, so the FDE will have a non-relocatable zero
1026       // (regardless of whether the PC encoding is absolute, pc-relative,
1027       // or data-relative) instead of a pointer to the start of the code.
1028 
1029       uint64_t pc_value = 0;
1030       switch (pc_size)
1031 	{
1032 	case 2:
1033 	  pc_value = elfcpp::Swap<16, big_endian>::readval(pfde);
1034 	  break;
1035 	case 4:
1036 	  pc_value = elfcpp::Swap<32, big_endian>::readval(pfde);
1037 	  break;
1038 	case 8:
1039 	  pc_value = elfcpp::Swap_unaligned<64, big_endian>::readval(pfde);
1040 	  break;
1041 	default:
1042 	  gold_unreachable();
1043 	}
1044 
1045       if (pc_value == 0)
1046 	{
1047 	  // This FDE applies to a discarded function.  We
1048 	  // can discard this FDE.
1049 	  object->add_merge_mapping(this, shndx, (pfde - 8) - pcontents,
1050 				    pfdeend - (pfde - 8), -1);
1051 	  return true;
1052 	}
1053 
1054       // Otherwise, reject the FDE.
1055       return false;
1056     }
1057 
1058   unsigned int symndx = relocs->next_symndx();
1059   if (symndx == -1U)
1060     return false;
1061 
1062   // There can be another reloc in the FDE, if the CIE specifies an
1063   // LSDA (language specific data area).  We currently don't care.  We
1064   // will care later if we want to optimize the LSDA from an absolute
1065   // pointer to a PC relative offset when generating a shared library.
1066   relocs->advance(pfdeend - pcontents);
1067 
1068   // Find the section index for code that this FDE describes.
1069   // If we have discarded the section, we can also discard the FDE.
1070   unsigned int fde_shndx;
1071   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1072   if (symndx >= symbols_size / sym_size)
1073     return false;
1074   elfcpp::Sym<size, big_endian> sym(symbols + symndx * sym_size);
1075   bool is_ordinary;
1076   fde_shndx = object->adjust_sym_shndx(symndx, sym.get_st_shndx(),
1077 				       &is_ordinary);
1078   bool is_discarded = (is_ordinary
1079 		       && fde_shndx != elfcpp::SHN_UNDEF
1080 		       && fde_shndx < object->shnum()
1081 		       && !object->is_section_included(fde_shndx));
1082 
1083   // Fetch the address range field from the FDE. The offset and size
1084   // of the field depends on the PC encoding given in the CIE, but
1085   // it is always an absolute value. If the address range is 0, this
1086   // FDE corresponds to a function that was discarded during optimization
1087   // (too late to discard the corresponding FDE).
1088   uint64_t address_range = 0;
1089   switch (pc_size)
1090     {
1091     case 2:
1092       address_range = elfcpp::Swap<16, big_endian>::readval(pfde + 2);
1093       break;
1094     case 4:
1095       address_range = elfcpp::Swap<32, big_endian>::readval(pfde + 4);
1096       break;
1097     case 8:
1098       address_range = elfcpp::Swap_unaligned<64, big_endian>::readval(pfde + 8);
1099       break;
1100     default:
1101       gold_unreachable();
1102     }
1103 
1104   if (is_discarded || address_range == 0)
1105     {
1106       // This FDE applies to a discarded function.  We
1107       // can discard this FDE.
1108       object->add_merge_mapping(this, shndx, (pfde - 8) - pcontents,
1109                                 pfdeend - (pfde - 8), -1);
1110       return true;
1111     }
1112 
1113   cie->add_fde(new Fde(object, shndx, (pfde - 8) - pcontents,
1114 		       pfde, pfdeend - pfde));
1115 
1116   return true;
1117 }
1118 
1119 // Add unwind information for a PLT.
1120 
1121 void
add_ehframe_for_plt(Output_data * plt,const unsigned char * cie_data,size_t cie_length,const unsigned char * fde_data,size_t fde_length)1122 Eh_frame::add_ehframe_for_plt(Output_data* plt, const unsigned char* cie_data,
1123 			      size_t cie_length, const unsigned char* fde_data,
1124 			      size_t fde_length)
1125 {
1126   Cie cie(NULL, 0, 0, elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4, "",
1127 	  cie_data, cie_length);
1128   Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
1129   Cie* pcie;
1130   if (find_cie != this->cie_offsets_.end())
1131     pcie = *find_cie;
1132   else
1133     {
1134       gold_assert(!this->mappings_are_done_);
1135       pcie = new Cie(cie);
1136       this->cie_offsets_.insert(pcie);
1137     }
1138 
1139   Fde* fde = new Fde(plt, fde_data, fde_length, this->mappings_are_done_);
1140   pcie->add_fde(fde);
1141 
1142   if (this->mappings_are_done_)
1143     this->final_data_size_ += align_address(fde_length + 8, this->addralign());
1144 }
1145 
1146 // Return the number of FDEs.
1147 
1148 unsigned int
fde_count() const1149 Eh_frame::fde_count() const
1150 {
1151   unsigned int ret = 0;
1152   for (Unmergeable_cie_offsets::const_iterator p =
1153 	 this->unmergeable_cie_offsets_.begin();
1154        p != this->unmergeable_cie_offsets_.end();
1155        ++p)
1156     ret += (*p)->fde_count();
1157   for (Cie_offsets::const_iterator p = this->cie_offsets_.begin();
1158        p != this->cie_offsets_.end();
1159        ++p)
1160     ret += (*p)->fde_count();
1161   return ret;
1162 }
1163 
1164 // Set the final data size.
1165 
1166 void
set_final_data_size()1167 Eh_frame::set_final_data_size()
1168 {
1169   // We can be called more than once if Layout::set_segment_offsets
1170   // finds a better mapping.  We don't want to add all the mappings
1171   // again.
1172   if (this->mappings_are_done_)
1173     {
1174       this->set_data_size(this->final_data_size_);
1175       return;
1176     }
1177 
1178   section_offset_type output_start = 0;
1179   if (this->is_offset_valid())
1180     output_start = this->offset() - this->output_section()->offset();
1181   section_offset_type output_offset = output_start;
1182 
1183   for (Unmergeable_cie_offsets::iterator p =
1184 	 this->unmergeable_cie_offsets_.begin();
1185        p != this->unmergeable_cie_offsets_.end();
1186        ++p)
1187     output_offset = (*p)->set_output_offset(output_offset,
1188 					    this->addralign(),
1189 					    this);
1190 
1191   for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1192        p != this->cie_offsets_.end();
1193        ++p)
1194     output_offset = (*p)->set_output_offset(output_offset,
1195 					    this->addralign(),
1196 					    this);
1197 
1198   this->mappings_are_done_ = true;
1199   this->final_data_size_ = output_offset - output_start;
1200 
1201   gold_assert((output_offset & (this->addralign() - 1)) == 0);
1202   this->set_data_size(this->final_data_size_);
1203 }
1204 
1205 // Return an output offset for an input offset.
1206 
1207 bool
do_output_offset(const Relobj * object,unsigned int shndx,section_offset_type offset,section_offset_type * poutput) const1208 Eh_frame::do_output_offset(const Relobj* object, unsigned int shndx,
1209 			   section_offset_type offset,
1210 			   section_offset_type* poutput) const
1211 {
1212   return object->merge_output_offset(shndx, offset, poutput);
1213 }
1214 
1215 // Write the data to the output file.
1216 
1217 void
do_write(Output_file * of)1218 Eh_frame::do_write(Output_file* of)
1219 {
1220   const off_t offset = this->offset();
1221   const off_t oview_size = this->data_size();
1222   unsigned char* const oview = of->get_output_view(offset, oview_size);
1223 
1224   switch (parameters->size_and_endianness())
1225     {
1226 #ifdef HAVE_TARGET_32_LITTLE
1227     case Parameters::TARGET_32_LITTLE:
1228       this->do_sized_write<32, false>(oview);
1229       break;
1230 #endif
1231 #ifdef HAVE_TARGET_32_BIG
1232     case Parameters::TARGET_32_BIG:
1233       this->do_sized_write<32, true>(oview);
1234       break;
1235 #endif
1236 #ifdef HAVE_TARGET_64_LITTLE
1237     case Parameters::TARGET_64_LITTLE:
1238       this->do_sized_write<64, false>(oview);
1239       break;
1240 #endif
1241 #ifdef HAVE_TARGET_64_BIG
1242     case Parameters::TARGET_64_BIG:
1243       this->do_sized_write<64, true>(oview);
1244       break;
1245 #endif
1246     default:
1247       gold_unreachable();
1248     }
1249 
1250   of->write_output_view(offset, oview_size, oview);
1251 }
1252 
1253 // Write the data to the output file--template version.
1254 
1255 template<int size, bool big_endian>
1256 void
do_sized_write(unsigned char * oview)1257 Eh_frame::do_sized_write(unsigned char* oview)
1258 {
1259   uint64_t address = this->address();
1260   unsigned int addralign = this->addralign();
1261   section_offset_type o = 0;
1262   const off_t output_offset = this->offset() - this->output_section()->offset();
1263   Post_fdes post_fdes;
1264   for (Unmergeable_cie_offsets::iterator p =
1265 	 this->unmergeable_cie_offsets_.begin();
1266        p != this->unmergeable_cie_offsets_.end();
1267        ++p)
1268     o = (*p)->write<size, big_endian>(oview, output_offset, o, address,
1269 				      addralign, this->eh_frame_hdr_,
1270 				      &post_fdes);
1271   for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1272        p != this->cie_offsets_.end();
1273        ++p)
1274     o = (*p)->write<size, big_endian>(oview, output_offset, o, address,
1275 				      addralign, this->eh_frame_hdr_,
1276 				      &post_fdes);
1277   for (Post_fdes::iterator p = post_fdes.begin();
1278        p != post_fdes.end();
1279        ++p)
1280     o = (*p).fde->write<size, big_endian>(oview, output_offset, o, address,
1281 					  addralign, (*p).cie_offset,
1282 					  (*p).fde_encoding,
1283 					  this->eh_frame_hdr_);
1284 }
1285 
1286 #ifdef HAVE_TARGET_32_LITTLE
1287 template
1288 Eh_frame::Eh_frame_section_disposition
1289 Eh_frame::add_ehframe_input_section<32, false>(
1290     Sized_relobj_file<32, false>* object,
1291     const unsigned char* symbols,
1292     section_size_type symbols_size,
1293     const unsigned char* symbol_names,
1294     section_size_type symbol_names_size,
1295     unsigned int shndx,
1296     unsigned int reloc_shndx,
1297     unsigned int reloc_type);
1298 #endif
1299 
1300 #ifdef HAVE_TARGET_32_BIG
1301 template
1302 Eh_frame::Eh_frame_section_disposition
1303 Eh_frame::add_ehframe_input_section<32, true>(
1304     Sized_relobj_file<32, true>* object,
1305     const unsigned char* symbols,
1306     section_size_type symbols_size,
1307     const unsigned char* symbol_names,
1308     section_size_type symbol_names_size,
1309     unsigned int shndx,
1310     unsigned int reloc_shndx,
1311     unsigned int reloc_type);
1312 #endif
1313 
1314 #ifdef HAVE_TARGET_64_LITTLE
1315 template
1316 Eh_frame::Eh_frame_section_disposition
1317 Eh_frame::add_ehframe_input_section<64, false>(
1318     Sized_relobj_file<64, false>* object,
1319     const unsigned char* symbols,
1320     section_size_type symbols_size,
1321     const unsigned char* symbol_names,
1322     section_size_type symbol_names_size,
1323     unsigned int shndx,
1324     unsigned int reloc_shndx,
1325     unsigned int reloc_type);
1326 #endif
1327 
1328 #ifdef HAVE_TARGET_64_BIG
1329 template
1330 Eh_frame::Eh_frame_section_disposition
1331 Eh_frame::add_ehframe_input_section<64, true>(
1332     Sized_relobj_file<64, true>* object,
1333     const unsigned char* symbols,
1334     section_size_type symbols_size,
1335     const unsigned char* symbol_names,
1336     section_size_type symbol_names_size,
1337     unsigned int shndx,
1338     unsigned int reloc_shndx,
1339     unsigned int reloc_type);
1340 #endif
1341 
1342 } // End namespace gold.
1343