1 // ehframe.cc -- handle exception frame sections for gold
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
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
42 // The exception frame header starts with four bytes:
44 // 0: The version number, currently 1.
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).
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).
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
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).
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).
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.
77 const int eh_frame_hdr_size = 4;
79 // Construct the exception frame header.
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),
87 any_unrecognized_eh_frame_sections_(false)
91 // Set the size of the exception frame header.
94 Eh_frame_hdr::set_final_data_size()
96 unsigned int data_size = eh_frame_hdr_size + 4;
97 if (!this->any_unrecognized_eh_frame_sections_)
99 unsigned int fde_count = this->eh_frame_data_->fde_count();
101 data_size += 4 + 8 * fde_count;
102 this->fde_offsets_.reserve(fde_count);
104 this->set_data_size(data_size);
107 // Write the data to the flie.
110 Eh_frame_hdr::do_write(Output_file* of)
112 if (parameters->get_size() == 32)
114 if (!parameters->is_big_endian())
116 #ifdef HAVE_TARGET_32_LITTLE
117 this->do_sized_write<32, false>(of);
124 #ifdef HAVE_TARGET_32_BIG
125 this->do_sized_write<32, true>(of);
131 else if (parameters->get_size() == 64)
133 if (!parameters->is_big_endian())
135 #ifdef HAVE_TARGET_64_LITTLE
136 this->do_sized_write<64, false>(of);
143 #ifdef HAVE_TARGET_64_BIG
144 this->do_sized_write<64, true>(of);
154 // Write the data to the file with the right endianness.
156 template<int size, bool big_endian>
158 Eh_frame_hdr::do_sized_write(Output_file* of)
160 const off_t off = this->offset();
161 const off_t oview_size = this->data_size();
162 unsigned char* const oview = of->get_output_view(off, oview_size);
167 // Write out a 4 byte PC relative offset to the address of the
168 // .eh_frame section.
169 oview[1] = elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4;
170 uint64_t eh_frame_address = this->eh_frame_section_->address();
171 uint64_t eh_frame_hdr_address = this->address();
172 uint64_t eh_frame_offset = (eh_frame_address -
173 (eh_frame_hdr_address + 4));
174 elfcpp::Swap<32, big_endian>::writeval(oview + 4, eh_frame_offset);
176 if (this->any_unrecognized_eh_frame_sections_
177 || this->fde_offsets_.empty())
179 // There are no FDEs, or we didn't recognize the format of the
180 // some of the .eh_frame sections, so we can't write out the
182 oview[2] = elfcpp::DW_EH_PE_omit;
183 oview[3] = elfcpp::DW_EH_PE_omit;
185 gold_assert(oview_size == 8);
189 oview[2] = elfcpp::DW_EH_PE_udata4;
190 oview[3] = elfcpp::DW_EH_PE_datarel | elfcpp::DW_EH_PE_sdata4;
192 elfcpp::Swap<32, big_endian>::writeval(oview + 8,
193 this->fde_offsets_.size());
195 // We have the offsets of the FDEs in the .eh_frame section. We
196 // couldn't easily get the PC values before, as they depend on
197 // relocations which are, of course, target specific. This code
198 // is run after all those relocations have been applied to the
199 // output file. Here we read the output file again to find the
200 // PC values. Then we sort the list and write it out.
202 Fde_addresses<size> fde_addresses(this->fde_offsets_.size());
203 this->get_fde_addresses<size, big_endian>(of, &this->fde_offsets_,
206 std::sort(fde_addresses.begin(), fde_addresses.end(),
207 Fde_address_compare<size>());
209 typename elfcpp::Elf_types<size>::Elf_Addr output_address;
210 output_address = this->address();
212 unsigned char* pfde = oview + 12;
213 for (typename Fde_addresses<size>::iterator p = fde_addresses.begin();
214 p != fde_addresses.end();
217 elfcpp::Swap<32, big_endian>::writeval(pfde,
218 p->first - output_address);
219 elfcpp::Swap<32, big_endian>::writeval(pfde + 4,
220 p->second - output_address);
224 gold_assert(pfde - oview == oview_size);
227 of->write_output_view(off, oview_size, oview);
230 // Given the offset FDE_OFFSET of an FDE in the .eh_frame section, and
231 // the contents of the .eh_frame section EH_FRAME_CONTENTS, where the
232 // FDE's encoding is FDE_ENCODING, return the output address of the
235 template<int size, bool big_endian>
236 typename elfcpp::Elf_types<size>::Elf_Addr
237 Eh_frame_hdr::get_fde_pc(
238 typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address,
239 const unsigned char* eh_frame_contents,
240 section_offset_type fde_offset,
241 unsigned char fde_encoding)
243 // The FDE starts with a 4 byte length and a 4 byte offset to the
244 // CIE. The PC follows.
245 const unsigned char* p = eh_frame_contents + fde_offset + 8;
247 typename elfcpp::Elf_types<size>::Elf_Addr pc;
248 bool is_signed = (fde_encoding & elfcpp::DW_EH_PE_signed) != 0;
249 int pc_size = fde_encoding & 7;
250 if (pc_size == elfcpp::DW_EH_PE_absptr)
253 pc_size = elfcpp::DW_EH_PE_udata4;
255 pc_size = elfcpp::DW_EH_PE_udata8;
262 case elfcpp::DW_EH_PE_udata2:
263 pc = elfcpp::Swap<16, big_endian>::readval(p);
265 pc = (pc ^ 0x8000) - 0x8000;
268 case elfcpp::DW_EH_PE_udata4:
269 pc = elfcpp::Swap<32, big_endian>::readval(p);
270 if (size > 32 && is_signed)
271 pc = (pc ^ 0x80000000) - 0x80000000;
274 case elfcpp::DW_EH_PE_udata8:
275 gold_assert(size == 64);
276 pc = elfcpp::Swap_unaligned<64, big_endian>::readval(p);
280 // All other cases were rejected in Eh_frame::read_cie.
284 switch (fde_encoding & 0xf0)
289 case elfcpp::DW_EH_PE_pcrel:
290 pc += eh_frame_address + fde_offset + 8;
294 // If other cases arise, then we have to handle them, or we have
295 // to reject them by returning false in Eh_frame::read_cie.
302 // Given an array of FDE offsets in the .eh_frame section, return an
303 // array of offsets from the exception frame header to the FDE's
304 // output PC and to the output address of the FDE itself. We get the
305 // FDE's PC by actually looking in the .eh_frame section we just wrote
306 // to the output file.
308 template<int size, bool big_endian>
310 Eh_frame_hdr::get_fde_addresses(Output_file* of,
311 const Fde_offsets* fde_offsets,
312 Fde_addresses<size>* fde_addresses)
314 typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address;
315 eh_frame_address = this->eh_frame_section_->address();
316 off_t eh_frame_offset = this->eh_frame_section_->offset();
317 off_t eh_frame_size = this->eh_frame_section_->data_size();
318 const unsigned char* eh_frame_contents = of->get_input_view(eh_frame_offset,
321 for (Fde_offsets::const_iterator p = fde_offsets->begin();
322 p != fde_offsets->end();
325 typename elfcpp::Elf_types<size>::Elf_Addr fde_pc;
326 fde_pc = this->get_fde_pc<size, big_endian>(eh_frame_address,
328 p->first, p->second);
329 fde_addresses->push_back(fde_pc, eh_frame_address + p->first);
332 of->free_input_view(eh_frame_offset, eh_frame_size, eh_frame_contents);
337 // Write the FDE to OVIEW starting at OFFSET. CIE_OFFSET is the
338 // offset of the CIE in OVIEW. FDE_ENCODING is the encoding, from the
339 // CIE. ADDRALIGN is the required alignment. Record the FDE pc for
340 // EH_FRAME_HDR. Return the new offset.
342 template<int size, bool big_endian>
344 Fde::write(unsigned char* oview, section_offset_type offset,
345 unsigned int addralign, section_offset_type cie_offset,
346 unsigned char fde_encoding, Eh_frame_hdr* eh_frame_hdr)
348 gold_assert((offset & (addralign - 1)) == 0);
350 size_t length = this->contents_.length();
352 // We add 8 when getting the aligned length to account for the
353 // length word and the CIE offset.
354 size_t aligned_full_length = align_address(length + 8, addralign);
356 // Write the length of the FDE as a 32-bit word. The length word
357 // does not include the four bytes of the length word itself, but it
358 // does include the offset to the CIE.
359 elfcpp::Swap<32, big_endian>::writeval(oview + offset,
360 aligned_full_length - 4);
362 // Write the offset to the CIE as a 32-bit word. This is the
363 // difference between the address of the offset word itself and the
365 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4,
366 offset + 4 - cie_offset);
368 // Copy the rest of the FDE. Note that this is run before
369 // relocation processing is done on this section, so the relocations
370 // will later be applied to the FDE data.
371 memcpy(oview + offset + 8, this->contents_.data(), length);
373 if (aligned_full_length > length + 8)
374 memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
376 // Tell the exception frame header about this FDE.
377 if (eh_frame_hdr != NULL)
378 eh_frame_hdr->record_fde(offset, fde_encoding);
380 return offset + aligned_full_length;
389 for (std::vector<Fde*>::iterator p = this->fdes_.begin();
390 p != this->fdes_.end();
395 // Set the output offset of a CIE. Return the new output offset.
398 Cie::set_output_offset(section_offset_type output_offset,
399 unsigned int addralign,
400 Merge_map* merge_map)
402 size_t length = this->contents_.length();
404 // Add 4 for length and 4 for zero CIE identifier tag.
407 merge_map->add_mapping(this->object_, this->shndx_, this->input_offset_,
408 length, output_offset);
410 length = align_address(length, addralign);
412 for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
413 p != this->fdes_.end();
416 (*p)->add_mapping(output_offset + length, merge_map);
418 size_t fde_length = (*p)->length();
419 fde_length = align_address(fde_length, addralign);
420 length += fde_length;
423 return output_offset + length;
426 // Write the CIE to OVIEW starting at OFFSET. EH_FRAME_HDR is for FDE
427 // recording. Round up the bytes to ADDRALIGN. Return the new
430 template<int size, bool big_endian>
432 Cie::write(unsigned char* oview, section_offset_type offset,
433 unsigned int addralign, Eh_frame_hdr* eh_frame_hdr)
435 gold_assert((offset & (addralign - 1)) == 0);
437 section_offset_type cie_offset = offset;
439 size_t length = this->contents_.length();
441 // We add 8 when getting the aligned length to account for the
442 // length word and the CIE tag.
443 size_t aligned_full_length = align_address(length + 8, addralign);
445 // Write the length of the CIE as a 32-bit word. The length word
446 // does not include the four bytes of the length word itself.
447 elfcpp::Swap<32, big_endian>::writeval(oview + offset,
448 aligned_full_length - 4);
450 // Write the tag which marks this as a CIE: a 32-bit zero.
451 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4, 0);
453 // Write out the CIE data.
454 memcpy(oview + offset + 8, this->contents_.data(), length);
456 if (aligned_full_length > length + 8)
457 memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
459 offset += aligned_full_length;
461 // Write out the associated FDEs.
462 unsigned char fde_encoding = this->fde_encoding_;
463 for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
464 p != this->fdes_.end();
466 offset = (*p)->write<size, big_endian>(oview, offset, addralign,
467 cie_offset, fde_encoding,
473 // We track all the CIEs we see, and merge them when possible. This
474 // works because each FDE holds an offset to the relevant CIE: we
475 // rewrite the FDEs to point to the merged CIE. This is worthwhile
476 // because in a typical C++ program many FDEs in many different object
477 // files will use the same CIE.
479 // An equality operator for Cie.
482 operator==(const Cie& cie1, const Cie& cie2)
484 return (cie1.personality_name_ == cie2.personality_name_
485 && cie1.contents_ == cie2.contents_);
488 // A less-than operator for Cie.
491 operator<(const Cie& cie1, const Cie& cie2)
493 if (cie1.personality_name_ != cie2.personality_name_)
494 return cie1.personality_name_ < cie2.personality_name_;
495 return cie1.contents_ < cie2.contents_;
501 : Output_section_data(Output_data::default_alignment()),
504 unmergeable_cie_offsets_(),
509 // Skip an LEB128, updating *PP to point to the next character.
510 // Return false if we ran off the end of the string.
513 Eh_frame::skip_leb128(const unsigned char** pp, const unsigned char* pend)
515 const unsigned char* p;
516 for (p = *pp; p < pend; ++p)
518 if ((*p & 0x80) == 0)
527 // Add input section SHNDX in OBJECT to an exception frame section.
528 // SYMBOLS is the contents of the symbol table section (size
529 // SYMBOLS_SIZE), SYMBOL_NAMES is the symbol names section (size
530 // SYMBOL_NAMES_SIZE). RELOC_SHNDX is the index of a relocation
531 // section applying to SHNDX, or 0 if none, or -1U if more than one.
532 // RELOC_TYPE is the type of the reloc section if there is one, either
533 // SHT_REL or SHT_RELA. We try to parse the input exception frame
534 // data into our data structures. If we can't do it, we return false
535 // to mean that the section should be handled as a normal input
538 template<int size, bool big_endian>
540 Eh_frame::add_ehframe_input_section(
541 Sized_relobj<size, big_endian>* object,
542 const unsigned char* symbols,
543 section_size_type symbols_size,
544 const unsigned char* symbol_names,
545 section_size_type symbol_names_size,
547 unsigned int reloc_shndx,
548 unsigned int reloc_type)
550 // Get the section contents.
551 section_size_type contents_len;
552 const unsigned char* pcontents = object->section_contents(shndx,
555 if (contents_len == 0)
558 // If this is the marker section for the end of the data, then
559 // return false to force it to be handled as an ordinary input
560 // section. If we don't do this, we won't correctly handle the case
561 // of unrecognized .eh_frame sections.
562 if (contents_len == 4
563 && elfcpp::Swap<32, big_endian>::readval(pcontents) == 0)
567 if (!this->do_add_ehframe_input_section(object, symbols, symbols_size,
568 symbol_names, symbol_names_size,
570 reloc_type, pcontents,
571 contents_len, &new_cies))
573 this->eh_frame_hdr_->found_unrecognized_eh_frame_section();
575 for (New_cies::iterator p = new_cies.begin();
583 // Now that we know we are using this section, record any new CIEs
585 for (New_cies::const_iterator p = new_cies.begin();
590 this->cie_offsets_.insert(p->first);
592 this->unmergeable_cie_offsets_.push_back(p->first);
598 // The bulk of the implementation of add_ehframe_input_section.
600 template<int size, bool big_endian>
602 Eh_frame::do_add_ehframe_input_section(
603 Sized_relobj<size, big_endian>* object,
604 const unsigned char* symbols,
605 section_size_type symbols_size,
606 const unsigned char* symbol_names,
607 section_size_type symbol_names_size,
609 unsigned int reloc_shndx,
610 unsigned int reloc_type,
611 const unsigned char* pcontents,
612 section_size_type contents_len,
615 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
616 Track_relocs<size, big_endian> relocs;
618 const unsigned char* p = pcontents;
619 const unsigned char* pend = p + contents_len;
621 // Get the contents of the reloc section if any.
622 if (!relocs.initialize(object, reloc_shndx, reloc_type))
625 // Keep track of which CIEs are at which offsets.
633 // There shouldn't be any relocations here.
634 if (relocs.advance(p + 4 - pcontents) > 0)
637 unsigned int len = elfcpp::Swap<32, big_endian>::readval(p);
641 // We should only find a zero-length entry at the end of the
647 // We don't support a 64-bit .eh_frame.
648 if (len == 0xffffffff)
650 if (static_cast<unsigned int>(pend - p) < len)
653 const unsigned char* const pentend = p + len;
657 if (relocs.advance(p + 4 - pcontents) > 0)
660 unsigned int id = elfcpp::Swap<32, big_endian>::readval(p);
666 if (!this->read_cie(object, shndx, symbols, symbols_size,
667 symbol_names, symbol_names_size,
668 pcontents, p, pentend, &relocs, &cies,
675 if (!this->read_fde(object, shndx, symbols, symbols_size,
676 pcontents, id, p, pentend, &relocs, &cies))
686 // Read a CIE. Return false if we can't parse the information.
688 template<int size, bool big_endian>
690 Eh_frame::read_cie(Sized_relobj<size, big_endian>* object,
692 const unsigned char* symbols,
693 section_size_type symbols_size,
694 const unsigned char* symbol_names,
695 section_size_type symbol_names_size,
696 const unsigned char* pcontents,
697 const unsigned char* pcie,
698 const unsigned char *pcieend,
699 Track_relocs<size, big_endian>* relocs,
700 Offsets_to_cie* cies,
703 bool mergeable = true;
705 // We need to find the personality routine if there is one, since we
706 // can only merge CIEs which use the same routine. We also need to
707 // find the FDE encoding if there is one, so that we can read the PC
710 const unsigned char* p = pcie;
714 unsigned char version = *p++;
715 if (version != 1 && version != 3)
718 const unsigned char* paug = p;
719 const void* paugendv = memchr(p, '\0', pcieend - p);
720 const unsigned char* paugend = static_cast<const unsigned char*>(paugendv);
725 if (paug[0] == 'e' && paug[1] == 'h')
727 // This is a CIE from gcc before version 3.0. We can't merge
728 // these. We can still read the FDEs.
733 if (pcieend - p < size / 8)
738 // Skip the code alignment.
739 if (!skip_leb128(&p, pcieend))
742 // Skip the data alignment.
743 if (!skip_leb128(&p, pcieend))
746 // Skip the return column.
755 if (!skip_leb128(&p, pcieend))
762 // Skip the augmentation size.
763 if (!skip_leb128(&p, pcieend))
767 unsigned char fde_encoding = elfcpp::DW_EH_PE_absptr;
769 while (*paug != '\0')
773 case 'L': // LSDA encoding.
779 case 'R': // FDE encoding.
783 switch (fde_encoding & 7)
785 case elfcpp::DW_EH_PE_absptr:
786 case elfcpp::DW_EH_PE_udata2:
787 case elfcpp::DW_EH_PE_udata4:
788 case elfcpp::DW_EH_PE_udata8:
791 // We don't expect to see any other cases here, and
792 // we're not prepared to handle them.
802 // Personality encoding.
806 unsigned char per_encoding = *p;
809 if ((per_encoding & 0x60) == 0x60)
811 unsigned int per_width;
812 switch (per_encoding & 7)
814 case elfcpp::DW_EH_PE_udata2:
817 case elfcpp::DW_EH_PE_udata4:
820 case elfcpp::DW_EH_PE_udata8:
823 case elfcpp::DW_EH_PE_absptr:
824 per_width = size / 8;
830 if ((per_encoding & 0xf0) == elfcpp::DW_EH_PE_aligned)
832 unsigned int len = p - pcie;
833 len += per_width - 1;
834 len &= ~ (per_width - 1);
835 if (static_cast<unsigned int>(pcieend - p) < len)
840 per_offset = p - pcontents;
842 if (static_cast<unsigned int>(pcieend - p) < per_width)
855 const char* personality_name = "";
856 if (per_offset != -1)
858 if (relocs->advance(per_offset) > 0)
860 if (relocs->next_offset() != per_offset)
863 unsigned int personality_symndx = relocs->next_symndx();
864 if (personality_symndx == -1U)
867 if (personality_symndx < object->local_symbol_count())
869 // We can only merge this CIE if the personality routine is
870 // a global symbol. We can still read the FDEs.
875 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
876 if (personality_symndx >= symbols_size / sym_size)
878 elfcpp::Sym<size, big_endian> sym(symbols
879 + (personality_symndx * sym_size));
880 unsigned int name_offset = sym.get_st_name();
881 if (name_offset >= symbol_names_size)
883 personality_name = (reinterpret_cast<const char*>(symbol_names)
887 int r = relocs->advance(per_offset + 1);
891 if (relocs->advance(pcieend - pcontents) > 0)
894 Cie cie(object, shndx, (pcie - 8) - pcontents, fde_encoding,
895 personality_name, pcie, pcieend - pcie);
896 Cie* cie_pointer = NULL;
899 Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
900 if (find_cie != this->cie_offsets_.end())
901 cie_pointer = *find_cie;
904 // See if we already saw this CIE in this object file.
905 for (New_cies::const_iterator pc = new_cies->begin();
906 pc != new_cies->end();
909 if (*(pc->first) == cie)
911 cie_pointer = pc->first;
918 if (cie_pointer == NULL)
920 cie_pointer = new Cie(cie);
921 new_cies->push_back(std::make_pair(cie_pointer, mergeable));
925 // We are deleting this CIE. Record that in our mapping from
926 // input sections to the output section. At this point we don't
927 // know for sure that we are doing a special mapping for this
928 // input section, but that's OK--if we don't do a special
929 // mapping, nobody will ever ask for the mapping we add here.
930 this->merge_map_.add_mapping(object, shndx, (pcie - 8) - pcontents,
931 pcieend - (pcie - 8), -1);
934 // Record this CIE plus the offset in the input section.
935 cies->insert(std::make_pair(pcie - pcontents, cie_pointer));
940 // Read an FDE. Return false if we can't parse the information.
942 template<int size, bool big_endian>
944 Eh_frame::read_fde(Sized_relobj<size, big_endian>* object,
946 const unsigned char* symbols,
947 section_size_type symbols_size,
948 const unsigned char* pcontents,
950 const unsigned char* pfde,
951 const unsigned char *pfdeend,
952 Track_relocs<size, big_endian>* relocs,
953 Offsets_to_cie* cies)
955 // OFFSET is the distance between the 4 bytes before PFDE to the
956 // start of the CIE. The offset we recorded for the CIE is 8 bytes
957 // after the start of the CIE--after the length and the zero tag.
958 unsigned int cie_offset = (pfde - 4 - pcontents) - offset + 8;
959 Offsets_to_cie::const_iterator pcie = cies->find(cie_offset);
960 if (pcie == cies->end())
962 Cie* cie = pcie->second;
964 // The FDE should start with a reloc to the start of the code which
966 if (relocs->advance(pfde - pcontents) > 0)
969 if (relocs->next_offset() != pfde - pcontents)
972 unsigned int symndx = relocs->next_symndx();
976 // There can be another reloc in the FDE, if the CIE specifies an
977 // LSDA (language specific data area). We currently don't care. We
978 // will care later if we want to optimize the LSDA from an absolute
979 // pointer to a PC relative offset when generating a shared library.
980 relocs->advance(pfdeend - pcontents);
982 unsigned int fde_shndx;
983 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
984 if (symndx >= symbols_size / sym_size)
986 elfcpp::Sym<size, big_endian> sym(symbols + symndx * sym_size);
987 fde_shndx = sym.get_st_shndx();
989 if (fde_shndx != elfcpp::SHN_UNDEF
990 && fde_shndx < object->shnum()
991 && !object->is_section_included(fde_shndx))
993 // This FDE applies to a section which we are discarding. We
994 // can discard this FDE.
995 this->merge_map_.add_mapping(object, shndx, (pfde - 8) - pcontents,
996 pfdeend - (pfde - 8), -1);
1000 cie->add_fde(new Fde(object, shndx, (pfde - 8) - pcontents,
1001 pfde, pfdeend - pfde));
1006 // Return the number of FDEs.
1009 Eh_frame::fde_count() const
1011 unsigned int ret = 0;
1012 for (Unmergeable_cie_offsets::const_iterator p =
1013 this->unmergeable_cie_offsets_.begin();
1014 p != this->unmergeable_cie_offsets_.end();
1016 ret += (*p)->fde_count();
1017 for (Cie_offsets::const_iterator p = this->cie_offsets_.begin();
1018 p != this->cie_offsets_.end();
1020 ret += (*p)->fde_count();
1024 // Set the final data size.
1027 Eh_frame::set_final_data_size()
1029 section_offset_type output_offset = 0;
1031 for (Unmergeable_cie_offsets::iterator p =
1032 this->unmergeable_cie_offsets_.begin();
1033 p != this->unmergeable_cie_offsets_.end();
1035 output_offset = (*p)->set_output_offset(output_offset,
1039 for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1040 p != this->cie_offsets_.end();
1042 output_offset = (*p)->set_output_offset(output_offset,
1046 gold_assert((output_offset & (this->addralign() - 1)) == 0);
1047 this->set_data_size(output_offset);
1050 // Return an output offset for an input offset.
1053 Eh_frame::do_output_offset(const Relobj* object, unsigned int shndx,
1054 section_offset_type offset,
1055 section_offset_type* poutput) const
1057 return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
1060 // Return whether this is the merge section for an input section.
1063 Eh_frame::do_is_merge_section_for(const Relobj* object,
1064 unsigned int shndx) const
1066 return this->merge_map_.is_merge_section_for(object, shndx);
1069 // Write the data to the output file.
1072 Eh_frame::do_write(Output_file* of)
1074 const off_t offset = this->offset();
1075 const off_t oview_size = this->data_size();
1076 unsigned char* const oview = of->get_output_view(offset, oview_size);
1078 if (parameters->get_size() == 32)
1080 if (!parameters->is_big_endian())
1082 #ifdef HAVE_TARGET_32_LITTLE
1083 this->do_sized_write<32, false>(oview);
1090 #ifdef HAVE_TARGET_32_BIG
1091 this->do_sized_write<32, true>(oview);
1097 else if (parameters->get_size() == 64)
1099 if (!parameters->is_big_endian())
1101 #ifdef HAVE_TARGET_64_LITTLE
1102 this->do_sized_write<64, false>(oview);
1109 #ifdef HAVE_TARGET_64_BIG
1110 this->do_sized_write<64, true>(oview);
1119 of->write_output_view(offset, oview_size, oview);
1122 // Write the data to the output file--template version.
1124 template<int size, bool big_endian>
1126 Eh_frame::do_sized_write(unsigned char* oview)
1128 unsigned int addralign = this->addralign();
1129 section_offset_type o = 0;
1130 for (Unmergeable_cie_offsets::iterator p =
1131 this->unmergeable_cie_offsets_.begin();
1132 p != this->unmergeable_cie_offsets_.end();
1134 o = (*p)->write<size, big_endian>(oview, o, addralign,
1135 this->eh_frame_hdr_);
1136 for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1137 p != this->cie_offsets_.end();
1139 o = (*p)->write<size, big_endian>(oview, o, addralign,
1140 this->eh_frame_hdr_);
1143 #ifdef HAVE_TARGET_32_LITTLE
1146 Eh_frame::add_ehframe_input_section<32, false>(
1147 Sized_relobj<32, false>* object,
1148 const unsigned char* symbols,
1149 section_size_type symbols_size,
1150 const unsigned char* symbol_names,
1151 section_size_type symbol_names_size,
1153 unsigned int reloc_shndx,
1154 unsigned int reloc_type);
1157 #ifdef HAVE_TARGET_32_BIG
1160 Eh_frame::add_ehframe_input_section<32, true>(
1161 Sized_relobj<32, true>* object,
1162 const unsigned char* symbols,
1163 section_size_type symbols_size,
1164 const unsigned char* symbol_names,
1165 section_size_type symbol_names_size,
1167 unsigned int reloc_shndx,
1168 unsigned int reloc_type);
1171 #ifdef HAVE_TARGET_64_LITTLE
1174 Eh_frame::add_ehframe_input_section<64, false>(
1175 Sized_relobj<64, false>* object,
1176 const unsigned char* symbols,
1177 section_size_type symbols_size,
1178 const unsigned char* symbol_names,
1179 section_size_type symbol_names_size,
1181 unsigned int reloc_shndx,
1182 unsigned int reloc_type);
1185 #ifdef HAVE_TARGET_64_BIG
1188 Eh_frame::add_ehframe_input_section<64, true>(
1189 Sized_relobj<64, true>* object,
1190 const unsigned char* symbols,
1191 section_size_type symbols_size,
1192 const unsigned char* symbol_names,
1193 section_size_type symbol_names_size,
1195 unsigned int reloc_shndx,
1196 unsigned int reloc_type);
1199 } // End namespace gold.