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 switch (parameters->size_and_endianness())
114 #ifdef HAVE_TARGET_32_LITTLE
115 case Parameters::TARGET_32_LITTLE:
116 this->do_sized_write<32, false>(of);
119 #ifdef HAVE_TARGET_32_BIG
120 case Parameters::TARGET_32_BIG:
121 this->do_sized_write<32, true>(of);
124 #ifdef HAVE_TARGET_64_LITTLE
125 case Parameters::TARGET_64_LITTLE:
126 this->do_sized_write<64, false>(of);
129 #ifdef HAVE_TARGET_64_BIG
130 case Parameters::TARGET_64_BIG:
131 this->do_sized_write<64, true>(of);
139 // Write the data to the file with the right endianness.
141 template<int size, bool big_endian>
143 Eh_frame_hdr::do_sized_write(Output_file* of)
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);
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);
161 if (this->any_unrecognized_eh_frame_sections_
162 || this->fde_offsets_.empty())
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
167 oview[2] = elfcpp::DW_EH_PE_omit;
168 oview[3] = elfcpp::DW_EH_PE_omit;
170 gold_assert(oview_size == 8);
174 oview[2] = elfcpp::DW_EH_PE_udata4;
175 oview[3] = elfcpp::DW_EH_PE_datarel | elfcpp::DW_EH_PE_sdata4;
177 elfcpp::Swap<32, big_endian>::writeval(oview + 8,
178 this->fde_offsets_.size());
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.
187 Fde_addresses<size> fde_addresses(this->fde_offsets_.size());
188 this->get_fde_addresses<size, big_endian>(of, &this->fde_offsets_,
191 std::sort(fde_addresses.begin(), fde_addresses.end(),
192 Fde_address_compare<size>());
194 typename elfcpp::Elf_types<size>::Elf_Addr output_address;
195 output_address = this->address();
197 unsigned char* pfde = oview + 12;
198 for (typename Fde_addresses<size>::iterator p = fde_addresses.begin();
199 p != fde_addresses.end();
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);
209 gold_assert(pfde - oview == oview_size);
212 of->write_output_view(off, oview_size, oview);
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
220 template<int size, bool big_endian>
221 typename elfcpp::Elf_types<size>::Elf_Addr
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)
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;
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)
238 pc_size = elfcpp::DW_EH_PE_udata4;
240 pc_size = elfcpp::DW_EH_PE_udata8;
247 case elfcpp::DW_EH_PE_udata2:
248 pc = elfcpp::Swap<16, big_endian>::readval(p);
250 pc = (pc ^ 0x8000) - 0x8000;
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;
259 case elfcpp::DW_EH_PE_udata8:
260 gold_assert(size == 64);
261 pc = elfcpp::Swap_unaligned<64, big_endian>::readval(p);
265 // All other cases were rejected in Eh_frame::read_cie.
269 switch (fde_encoding & 0xf0)
274 case elfcpp::DW_EH_PE_pcrel:
275 pc += eh_frame_address + fde_offset + 8;
279 // If other cases arise, then we have to handle them, or we have
280 // to reject them by returning false in Eh_frame::read_cie.
287 // Given an array of FDE offsets in the .eh_frame section, return an
288 // array of offsets from the exception frame header to the FDE's
289 // output PC and to the output address of the FDE itself. We get the
290 // FDE's PC by actually looking in the .eh_frame section we just wrote
291 // to the output file.
293 template<int size, bool big_endian>
295 Eh_frame_hdr::get_fde_addresses(Output_file* of,
296 const Fde_offsets* fde_offsets,
297 Fde_addresses<size>* fde_addresses)
299 typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address;
300 eh_frame_address = this->eh_frame_section_->address();
301 off_t eh_frame_offset = this->eh_frame_section_->offset();
302 off_t eh_frame_size = this->eh_frame_section_->data_size();
303 const unsigned char* eh_frame_contents = of->get_input_view(eh_frame_offset,
306 for (Fde_offsets::const_iterator p = fde_offsets->begin();
307 p != fde_offsets->end();
310 typename elfcpp::Elf_types<size>::Elf_Addr fde_pc;
311 fde_pc = this->get_fde_pc<size, big_endian>(eh_frame_address,
313 p->first, p->second);
314 fde_addresses->push_back(fde_pc, eh_frame_address + p->first);
317 of->free_input_view(eh_frame_offset, eh_frame_size, eh_frame_contents);
322 // Write the FDE to OVIEW starting at OFFSET. CIE_OFFSET is the
323 // offset of the CIE in OVIEW. FDE_ENCODING is the encoding, from the
324 // CIE. ADDRALIGN is the required alignment. Record the FDE pc for
325 // EH_FRAME_HDR. Return the new offset.
327 template<int size, bool big_endian>
329 Fde::write(unsigned char* oview, section_offset_type offset,
330 unsigned int addralign, section_offset_type cie_offset,
331 unsigned char fde_encoding, Eh_frame_hdr* eh_frame_hdr)
333 gold_assert((offset & (addralign - 1)) == 0);
335 size_t length = this->contents_.length();
337 // We add 8 when getting the aligned length to account for the
338 // length word and the CIE offset.
339 size_t aligned_full_length = align_address(length + 8, addralign);
341 // Write the length of the FDE as a 32-bit word. The length word
342 // does not include the four bytes of the length word itself, but it
343 // does include the offset to the CIE.
344 elfcpp::Swap<32, big_endian>::writeval(oview + offset,
345 aligned_full_length - 4);
347 // Write the offset to the CIE as a 32-bit word. This is the
348 // difference between the address of the offset word itself and the
350 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4,
351 offset + 4 - cie_offset);
353 // Copy the rest of the FDE. Note that this is run before
354 // relocation processing is done on this section, so the relocations
355 // will later be applied to the FDE data.
356 memcpy(oview + offset + 8, this->contents_.data(), length);
358 if (aligned_full_length > length + 8)
359 memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
361 // Tell the exception frame header about this FDE.
362 if (eh_frame_hdr != NULL)
363 eh_frame_hdr->record_fde(offset, fde_encoding);
365 return offset + aligned_full_length;
374 for (std::vector<Fde*>::iterator p = this->fdes_.begin();
375 p != this->fdes_.end();
380 // Set the output offset of a CIE. Return the new output offset.
383 Cie::set_output_offset(section_offset_type output_offset,
384 unsigned int addralign,
385 Merge_map* merge_map)
387 size_t length = this->contents_.length();
389 // Add 4 for length and 4 for zero CIE identifier tag.
392 merge_map->add_mapping(this->object_, this->shndx_, this->input_offset_,
393 length, output_offset);
395 length = align_address(length, addralign);
397 for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
398 p != this->fdes_.end();
401 (*p)->add_mapping(output_offset + length, merge_map);
403 size_t fde_length = (*p)->length();
404 fde_length = align_address(fde_length, addralign);
405 length += fde_length;
408 return output_offset + length;
411 // Write the CIE to OVIEW starting at OFFSET. EH_FRAME_HDR is for FDE
412 // recording. Round up the bytes to ADDRALIGN. Return the new
415 template<int size, bool big_endian>
417 Cie::write(unsigned char* oview, section_offset_type offset,
418 unsigned int addralign, Eh_frame_hdr* eh_frame_hdr)
420 gold_assert((offset & (addralign - 1)) == 0);
422 section_offset_type cie_offset = offset;
424 size_t length = this->contents_.length();
426 // We add 8 when getting the aligned length to account for the
427 // length word and the CIE tag.
428 size_t aligned_full_length = align_address(length + 8, addralign);
430 // Write the length of the CIE as a 32-bit word. The length word
431 // does not include the four bytes of the length word itself.
432 elfcpp::Swap<32, big_endian>::writeval(oview + offset,
433 aligned_full_length - 4);
435 // Write the tag which marks this as a CIE: a 32-bit zero.
436 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4, 0);
438 // Write out the CIE data.
439 memcpy(oview + offset + 8, this->contents_.data(), length);
441 if (aligned_full_length > length + 8)
442 memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
444 offset += aligned_full_length;
446 // Write out the associated FDEs.
447 unsigned char fde_encoding = this->fde_encoding_;
448 for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
449 p != this->fdes_.end();
451 offset = (*p)->write<size, big_endian>(oview, offset, addralign,
452 cie_offset, fde_encoding,
458 // We track all the CIEs we see, and merge them when possible. This
459 // works because each FDE holds an offset to the relevant CIE: we
460 // rewrite the FDEs to point to the merged CIE. This is worthwhile
461 // because in a typical C++ program many FDEs in many different object
462 // files will use the same CIE.
464 // An equality operator for Cie.
467 operator==(const Cie& cie1, const Cie& cie2)
469 return (cie1.personality_name_ == cie2.personality_name_
470 && cie1.contents_ == cie2.contents_);
473 // A less-than operator for Cie.
476 operator<(const Cie& cie1, const Cie& cie2)
478 if (cie1.personality_name_ != cie2.personality_name_)
479 return cie1.personality_name_ < cie2.personality_name_;
480 return cie1.contents_ < cie2.contents_;
486 : Output_section_data(Output_data::default_alignment()),
489 unmergeable_cie_offsets_(),
494 // Skip an LEB128, updating *PP to point to the next character.
495 // Return false if we ran off the end of the string.
498 Eh_frame::skip_leb128(const unsigned char** pp, const unsigned char* pend)
500 const unsigned char* p;
501 for (p = *pp; p < pend; ++p)
503 if ((*p & 0x80) == 0)
512 // Add input section SHNDX in OBJECT to an exception frame section.
513 // SYMBOLS is the contents of the symbol table section (size
514 // SYMBOLS_SIZE), SYMBOL_NAMES is the symbol names section (size
515 // SYMBOL_NAMES_SIZE). RELOC_SHNDX is the index of a relocation
516 // section applying to SHNDX, or 0 if none, or -1U if more than one.
517 // RELOC_TYPE is the type of the reloc section if there is one, either
518 // SHT_REL or SHT_RELA. We try to parse the input exception frame
519 // data into our data structures. If we can't do it, we return false
520 // to mean that the section should be handled as a normal input
523 template<int size, bool big_endian>
525 Eh_frame::add_ehframe_input_section(
526 Sized_relobj<size, big_endian>* object,
527 const unsigned char* symbols,
528 section_size_type symbols_size,
529 const unsigned char* symbol_names,
530 section_size_type symbol_names_size,
532 unsigned int reloc_shndx,
533 unsigned int reloc_type)
535 // Get the section contents.
536 section_size_type contents_len;
537 const unsigned char* pcontents = object->section_contents(shndx,
540 if (contents_len == 0)
543 // If this is the marker section for the end of the data, then
544 // return false to force it to be handled as an ordinary input
545 // section. If we don't do this, we won't correctly handle the case
546 // of unrecognized .eh_frame sections.
547 if (contents_len == 4
548 && elfcpp::Swap<32, big_endian>::readval(pcontents) == 0)
552 if (!this->do_add_ehframe_input_section(object, symbols, symbols_size,
553 symbol_names, symbol_names_size,
555 reloc_type, pcontents,
556 contents_len, &new_cies))
558 this->eh_frame_hdr_->found_unrecognized_eh_frame_section();
560 for (New_cies::iterator p = new_cies.begin();
568 // Now that we know we are using this section, record any new CIEs
570 for (New_cies::const_iterator p = new_cies.begin();
575 this->cie_offsets_.insert(p->first);
577 this->unmergeable_cie_offsets_.push_back(p->first);
583 // The bulk of the implementation of add_ehframe_input_section.
585 template<int size, bool big_endian>
587 Eh_frame::do_add_ehframe_input_section(
588 Sized_relobj<size, big_endian>* object,
589 const unsigned char* symbols,
590 section_size_type symbols_size,
591 const unsigned char* symbol_names,
592 section_size_type symbol_names_size,
594 unsigned int reloc_shndx,
595 unsigned int reloc_type,
596 const unsigned char* pcontents,
597 section_size_type contents_len,
600 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
601 Track_relocs<size, big_endian> relocs;
603 const unsigned char* p = pcontents;
604 const unsigned char* pend = p + contents_len;
606 // Get the contents of the reloc section if any.
607 if (!relocs.initialize(object, reloc_shndx, reloc_type))
610 // Keep track of which CIEs are at which offsets.
618 // There shouldn't be any relocations here.
619 if (relocs.advance(p + 4 - pcontents) > 0)
622 unsigned int len = elfcpp::Swap<32, big_endian>::readval(p);
626 // We should only find a zero-length entry at the end of the
632 // We don't support a 64-bit .eh_frame.
633 if (len == 0xffffffff)
635 if (static_cast<unsigned int>(pend - p) < len)
638 const unsigned char* const pentend = p + len;
642 if (relocs.advance(p + 4 - pcontents) > 0)
645 unsigned int id = elfcpp::Swap<32, big_endian>::readval(p);
651 if (!this->read_cie(object, shndx, symbols, symbols_size,
652 symbol_names, symbol_names_size,
653 pcontents, p, pentend, &relocs, &cies,
660 if (!this->read_fde(object, shndx, symbols, symbols_size,
661 pcontents, id, p, pentend, &relocs, &cies))
671 // Read a CIE. Return false if we can't parse the information.
673 template<int size, bool big_endian>
675 Eh_frame::read_cie(Sized_relobj<size, big_endian>* object,
677 const unsigned char* symbols,
678 section_size_type symbols_size,
679 const unsigned char* symbol_names,
680 section_size_type symbol_names_size,
681 const unsigned char* pcontents,
682 const unsigned char* pcie,
683 const unsigned char *pcieend,
684 Track_relocs<size, big_endian>* relocs,
685 Offsets_to_cie* cies,
688 bool mergeable = true;
690 // We need to find the personality routine if there is one, since we
691 // can only merge CIEs which use the same routine. We also need to
692 // find the FDE encoding if there is one, so that we can read the PC
695 const unsigned char* p = pcie;
699 unsigned char version = *p++;
700 if (version != 1 && version != 3)
703 const unsigned char* paug = p;
704 const void* paugendv = memchr(p, '\0', pcieend - p);
705 const unsigned char* paugend = static_cast<const unsigned char*>(paugendv);
710 if (paug[0] == 'e' && paug[1] == 'h')
712 // This is a CIE from gcc before version 3.0. We can't merge
713 // these. We can still read the FDEs.
718 if (pcieend - p < size / 8)
723 // Skip the code alignment.
724 if (!skip_leb128(&p, pcieend))
727 // Skip the data alignment.
728 if (!skip_leb128(&p, pcieend))
731 // Skip the return column.
740 if (!skip_leb128(&p, pcieend))
747 // Skip the augmentation size.
748 if (!skip_leb128(&p, pcieend))
752 unsigned char fde_encoding = elfcpp::DW_EH_PE_absptr;
754 while (*paug != '\0')
758 case 'L': // LSDA encoding.
764 case 'R': // FDE encoding.
768 switch (fde_encoding & 7)
770 case elfcpp::DW_EH_PE_absptr:
771 case elfcpp::DW_EH_PE_udata2:
772 case elfcpp::DW_EH_PE_udata4:
773 case elfcpp::DW_EH_PE_udata8:
776 // We don't expect to see any other cases here, and
777 // we're not prepared to handle them.
787 // Personality encoding.
791 unsigned char per_encoding = *p;
794 if ((per_encoding & 0x60) == 0x60)
796 unsigned int per_width;
797 switch (per_encoding & 7)
799 case elfcpp::DW_EH_PE_udata2:
802 case elfcpp::DW_EH_PE_udata4:
805 case elfcpp::DW_EH_PE_udata8:
808 case elfcpp::DW_EH_PE_absptr:
809 per_width = size / 8;
815 if ((per_encoding & 0xf0) == elfcpp::DW_EH_PE_aligned)
817 unsigned int len = p - pcie;
818 len += per_width - 1;
819 len &= ~ (per_width - 1);
820 if (static_cast<unsigned int>(pcieend - p) < len)
825 per_offset = p - pcontents;
827 if (static_cast<unsigned int>(pcieend - p) < per_width)
840 const char* personality_name = "";
841 if (per_offset != -1)
843 if (relocs->advance(per_offset) > 0)
845 if (relocs->next_offset() != per_offset)
848 unsigned int personality_symndx = relocs->next_symndx();
849 if (personality_symndx == -1U)
852 if (personality_symndx < object->local_symbol_count())
854 // We can only merge this CIE if the personality routine is
855 // a global symbol. We can still read the FDEs.
860 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
861 if (personality_symndx >= symbols_size / sym_size)
863 elfcpp::Sym<size, big_endian> sym(symbols
864 + (personality_symndx * sym_size));
865 unsigned int name_offset = sym.get_st_name();
866 if (name_offset >= symbol_names_size)
868 personality_name = (reinterpret_cast<const char*>(symbol_names)
872 int r = relocs->advance(per_offset + 1);
876 if (relocs->advance(pcieend - pcontents) > 0)
879 Cie cie(object, shndx, (pcie - 8) - pcontents, fde_encoding,
880 personality_name, pcie, pcieend - pcie);
881 Cie* cie_pointer = NULL;
884 Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
885 if (find_cie != this->cie_offsets_.end())
886 cie_pointer = *find_cie;
889 // See if we already saw this CIE in this object file.
890 for (New_cies::const_iterator pc = new_cies->begin();
891 pc != new_cies->end();
894 if (*(pc->first) == cie)
896 cie_pointer = pc->first;
903 if (cie_pointer == NULL)
905 cie_pointer = new Cie(cie);
906 new_cies->push_back(std::make_pair(cie_pointer, mergeable));
910 // We are deleting this CIE. Record that in our mapping from
911 // input sections to the output section. At this point we don't
912 // know for sure that we are doing a special mapping for this
913 // input section, but that's OK--if we don't do a special
914 // mapping, nobody will ever ask for the mapping we add here.
915 this->merge_map_.add_mapping(object, shndx, (pcie - 8) - pcontents,
916 pcieend - (pcie - 8), -1);
919 // Record this CIE plus the offset in the input section.
920 cies->insert(std::make_pair(pcie - pcontents, cie_pointer));
925 // Read an FDE. Return false if we can't parse the information.
927 template<int size, bool big_endian>
929 Eh_frame::read_fde(Sized_relobj<size, big_endian>* object,
931 const unsigned char* symbols,
932 section_size_type symbols_size,
933 const unsigned char* pcontents,
935 const unsigned char* pfde,
936 const unsigned char *pfdeend,
937 Track_relocs<size, big_endian>* relocs,
938 Offsets_to_cie* cies)
940 // OFFSET is the distance between the 4 bytes before PFDE to the
941 // start of the CIE. The offset we recorded for the CIE is 8 bytes
942 // after the start of the CIE--after the length and the zero tag.
943 unsigned int cie_offset = (pfde - 4 - pcontents) - offset + 8;
944 Offsets_to_cie::const_iterator pcie = cies->find(cie_offset);
945 if (pcie == cies->end())
947 Cie* cie = pcie->second;
949 // The FDE should start with a reloc to the start of the code which
951 if (relocs->advance(pfde - pcontents) > 0)
954 if (relocs->next_offset() != pfde - pcontents)
957 unsigned int symndx = relocs->next_symndx();
961 // There can be another reloc in the FDE, if the CIE specifies an
962 // LSDA (language specific data area). We currently don't care. We
963 // will care later if we want to optimize the LSDA from an absolute
964 // pointer to a PC relative offset when generating a shared library.
965 relocs->advance(pfdeend - pcontents);
967 unsigned int fde_shndx;
968 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
969 if (symndx >= symbols_size / sym_size)
971 elfcpp::Sym<size, big_endian> sym(symbols + symndx * sym_size);
972 fde_shndx = sym.get_st_shndx();
974 if (fde_shndx != elfcpp::SHN_UNDEF
975 && fde_shndx < object->shnum()
976 && !object->is_section_included(fde_shndx))
978 // This FDE applies to a section which we are discarding. We
979 // can discard this FDE.
980 this->merge_map_.add_mapping(object, shndx, (pfde - 8) - pcontents,
981 pfdeend - (pfde - 8), -1);
985 cie->add_fde(new Fde(object, shndx, (pfde - 8) - pcontents,
986 pfde, pfdeend - pfde));
991 // Return the number of FDEs.
994 Eh_frame::fde_count() const
996 unsigned int ret = 0;
997 for (Unmergeable_cie_offsets::const_iterator p =
998 this->unmergeable_cie_offsets_.begin();
999 p != this->unmergeable_cie_offsets_.end();
1001 ret += (*p)->fde_count();
1002 for (Cie_offsets::const_iterator p = this->cie_offsets_.begin();
1003 p != this->cie_offsets_.end();
1005 ret += (*p)->fde_count();
1009 // Set the final data size.
1012 Eh_frame::set_final_data_size()
1014 section_offset_type output_offset = 0;
1016 for (Unmergeable_cie_offsets::iterator p =
1017 this->unmergeable_cie_offsets_.begin();
1018 p != this->unmergeable_cie_offsets_.end();
1020 output_offset = (*p)->set_output_offset(output_offset,
1024 for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1025 p != this->cie_offsets_.end();
1027 output_offset = (*p)->set_output_offset(output_offset,
1031 gold_assert((output_offset & (this->addralign() - 1)) == 0);
1032 this->set_data_size(output_offset);
1035 // Return an output offset for an input offset.
1038 Eh_frame::do_output_offset(const Relobj* object, unsigned int shndx,
1039 section_offset_type offset,
1040 section_offset_type* poutput) const
1042 return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
1045 // Return whether this is the merge section for an input section.
1048 Eh_frame::do_is_merge_section_for(const Relobj* object,
1049 unsigned int shndx) const
1051 return this->merge_map_.is_merge_section_for(object, shndx);
1054 // Write the data to the output file.
1057 Eh_frame::do_write(Output_file* of)
1059 const off_t offset = this->offset();
1060 const off_t oview_size = this->data_size();
1061 unsigned char* const oview = of->get_output_view(offset, oview_size);
1063 switch (parameters->size_and_endianness())
1065 #ifdef HAVE_TARGET_32_LITTLE
1066 case Parameters::TARGET_32_LITTLE:
1067 this->do_sized_write<32, false>(oview);
1070 #ifdef HAVE_TARGET_32_BIG
1071 case Parameters::TARGET_32_BIG:
1072 this->do_sized_write<32, true>(oview);
1075 #ifdef HAVE_TARGET_64_LITTLE
1076 case Parameters::TARGET_64_LITTLE:
1077 this->do_sized_write<64, false>(oview);
1080 #ifdef HAVE_TARGET_64_BIG
1081 case Parameters::TARGET_64_BIG:
1082 this->do_sized_write<64, true>(oview);
1089 of->write_output_view(offset, oview_size, oview);
1092 // Write the data to the output file--template version.
1094 template<int size, bool big_endian>
1096 Eh_frame::do_sized_write(unsigned char* oview)
1098 unsigned int addralign = this->addralign();
1099 section_offset_type o = 0;
1100 for (Unmergeable_cie_offsets::iterator p =
1101 this->unmergeable_cie_offsets_.begin();
1102 p != this->unmergeable_cie_offsets_.end();
1104 o = (*p)->write<size, big_endian>(oview, o, addralign,
1105 this->eh_frame_hdr_);
1106 for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1107 p != this->cie_offsets_.end();
1109 o = (*p)->write<size, big_endian>(oview, o, addralign,
1110 this->eh_frame_hdr_);
1113 #ifdef HAVE_TARGET_32_LITTLE
1116 Eh_frame::add_ehframe_input_section<32, false>(
1117 Sized_relobj<32, false>* object,
1118 const unsigned char* symbols,
1119 section_size_type symbols_size,
1120 const unsigned char* symbol_names,
1121 section_size_type symbol_names_size,
1123 unsigned int reloc_shndx,
1124 unsigned int reloc_type);
1127 #ifdef HAVE_TARGET_32_BIG
1130 Eh_frame::add_ehframe_input_section<32, true>(
1131 Sized_relobj<32, true>* object,
1132 const unsigned char* symbols,
1133 section_size_type symbols_size,
1134 const unsigned char* symbol_names,
1135 section_size_type symbol_names_size,
1137 unsigned int reloc_shndx,
1138 unsigned int reloc_type);
1141 #ifdef HAVE_TARGET_64_LITTLE
1144 Eh_frame::add_ehframe_input_section<64, false>(
1145 Sized_relobj<64, false>* object,
1146 const unsigned char* symbols,
1147 section_size_type symbols_size,
1148 const unsigned char* symbol_names,
1149 section_size_type symbol_names_size,
1151 unsigned int reloc_shndx,
1152 unsigned int reloc_type);
1155 #ifdef HAVE_TARGET_64_BIG
1158 Eh_frame::add_ehframe_input_section<64, true>(
1159 Sized_relobj<64, true>* object,
1160 const unsigned char* symbols,
1161 section_size_type symbols_size,
1162 const unsigned char* symbol_names,
1163 section_size_type symbol_names_size,
1165 unsigned int reloc_shndx,
1166 unsigned int reloc_type);
1169 } // End namespace gold.