1 // ehframe.cc -- handle exception frame sections for gold
3 // Copyright 2006, 2007, 2008, 2010, 2011, 2012 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),
92 // Set the size of the exception frame header.
95 Eh_frame_hdr::set_final_data_size()
97 unsigned int data_size = eh_frame_hdr_size + 4;
98 if (!this->any_unrecognized_eh_frame_sections_)
100 unsigned int fde_count = this->eh_frame_data_->fde_count();
102 data_size += 4 + 8 * fde_count;
103 this->fde_offsets_.reserve(fde_count);
105 this->set_data_size(data_size);
106 // We need a lock for updating the fde_offsets_ vector while writing
108 this->lock_ = new Lock();
111 // Write the data to the file.
114 Eh_frame_hdr::do_write(Output_file* of)
116 switch (parameters->size_and_endianness())
118 #ifdef HAVE_TARGET_32_LITTLE
119 case Parameters::TARGET_32_LITTLE:
120 this->do_sized_write<32, false>(of);
123 #ifdef HAVE_TARGET_32_BIG
124 case Parameters::TARGET_32_BIG:
125 this->do_sized_write<32, true>(of);
128 #ifdef HAVE_TARGET_64_LITTLE
129 case Parameters::TARGET_64_LITTLE:
130 this->do_sized_write<64, false>(of);
133 #ifdef HAVE_TARGET_64_BIG
134 case Parameters::TARGET_64_BIG:
135 this->do_sized_write<64, true>(of);
143 // Write the data to the file with the right endianness.
145 template<int size, bool big_endian>
147 Eh_frame_hdr::do_sized_write(Output_file* of)
149 const off_t off = this->offset();
150 const off_t oview_size = this->data_size();
151 unsigned char* const oview = of->get_output_view(off, oview_size);
156 // Write out a 4 byte PC relative offset to the address of the
157 // .eh_frame section.
158 oview[1] = elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4;
159 uint64_t eh_frame_address = this->eh_frame_section_->address();
160 uint64_t eh_frame_hdr_address = this->address();
161 uint64_t eh_frame_offset = (eh_frame_address -
162 (eh_frame_hdr_address + 4));
163 elfcpp::Swap<32, big_endian>::writeval(oview + 4, eh_frame_offset);
165 if (this->any_unrecognized_eh_frame_sections_
166 || this->fde_offsets_.empty())
168 // There are no FDEs, or we didn't recognize the format of the
169 // some of the .eh_frame sections, so we can't write out the
171 oview[2] = elfcpp::DW_EH_PE_omit;
172 oview[3] = elfcpp::DW_EH_PE_omit;
174 gold_assert(oview_size == 8);
178 oview[2] = elfcpp::DW_EH_PE_udata4;
179 oview[3] = elfcpp::DW_EH_PE_datarel | elfcpp::DW_EH_PE_sdata4;
181 elfcpp::Swap<32, big_endian>::writeval(oview + 8,
182 this->fde_offsets_.size());
184 // We have the offsets of the FDEs in the .eh_frame section. We
185 // couldn't easily get the PC values before, as they depend on
186 // relocations which are, of course, target specific. This code
187 // is run after all those relocations have been applied to the
188 // output file. Here we read the output file again to find the
189 // PC values. Then we sort the list and write it out.
191 Fde_addresses<size> fde_addresses(this->fde_offsets_.size());
192 this->get_fde_addresses<size, big_endian>(of, &this->fde_offsets_,
195 std::sort(fde_addresses.begin(), fde_addresses.end(),
196 Fde_address_compare<size>());
198 typename elfcpp::Elf_types<size>::Elf_Addr output_address;
199 output_address = this->address();
201 unsigned char* pfde = oview + 12;
202 for (typename Fde_addresses<size>::iterator p = fde_addresses.begin();
203 p != fde_addresses.end();
206 elfcpp::Swap<32, big_endian>::writeval(pfde,
207 p->first - output_address);
208 elfcpp::Swap<32, big_endian>::writeval(pfde + 4,
209 p->second - output_address);
213 gold_assert(pfde - oview == oview_size);
216 of->write_output_view(off, oview_size, oview);
219 // Given the offset FDE_OFFSET of an FDE in the .eh_frame section, and
220 // the contents of the .eh_frame section EH_FRAME_CONTENTS, where the
221 // FDE's encoding is FDE_ENCODING, return the output address of the
224 template<int size, bool big_endian>
225 typename elfcpp::Elf_types<size>::Elf_Addr
226 Eh_frame_hdr::get_fde_pc(
227 typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address,
228 const unsigned char* eh_frame_contents,
229 section_offset_type fde_offset,
230 unsigned char fde_encoding)
232 // The FDE starts with a 4 byte length and a 4 byte offset to the
233 // CIE. The PC follows.
234 const unsigned char* p = eh_frame_contents + fde_offset + 8;
236 typename elfcpp::Elf_types<size>::Elf_Addr pc;
237 bool is_signed = (fde_encoding & elfcpp::DW_EH_PE_signed) != 0;
238 int pc_size = fde_encoding & 7;
239 if (pc_size == elfcpp::DW_EH_PE_absptr)
242 pc_size = elfcpp::DW_EH_PE_udata4;
244 pc_size = elfcpp::DW_EH_PE_udata8;
251 case elfcpp::DW_EH_PE_udata2:
252 pc = elfcpp::Swap<16, big_endian>::readval(p);
254 pc = (pc ^ 0x8000) - 0x8000;
257 case elfcpp::DW_EH_PE_udata4:
258 pc = elfcpp::Swap<32, big_endian>::readval(p);
259 if (size > 32 && is_signed)
260 pc = (pc ^ 0x80000000) - 0x80000000;
263 case elfcpp::DW_EH_PE_udata8:
264 gold_assert(size == 64);
265 pc = elfcpp::Swap_unaligned<64, big_endian>::readval(p);
269 // All other cases were rejected in Eh_frame::read_cie.
273 switch (fde_encoding & 0x70)
278 case elfcpp::DW_EH_PE_pcrel:
279 pc += eh_frame_address + fde_offset + 8;
282 case elfcpp::DW_EH_PE_datarel:
283 pc += parameters->target().ehframe_datarel_base();
287 // If other cases arise, then we have to handle them, or we have
288 // to reject them by returning false in Eh_frame::read_cie.
292 gold_assert((fde_encoding & elfcpp::DW_EH_PE_indirect) == 0);
297 // Given an array of FDE offsets in the .eh_frame section, return an
298 // array of offsets from the exception frame header to the FDE's
299 // output PC and to the output address of the FDE itself. We get the
300 // FDE's PC by actually looking in the .eh_frame section we just wrote
301 // to the output file.
303 template<int size, bool big_endian>
305 Eh_frame_hdr::get_fde_addresses(Output_file* of,
306 const Fde_offsets* fde_offsets,
307 Fde_addresses<size>* fde_addresses)
309 typename elfcpp::Elf_types<size>::Elf_Addr eh_frame_address;
310 eh_frame_address = this->eh_frame_section_->address();
311 off_t eh_frame_offset = this->eh_frame_section_->offset();
312 off_t eh_frame_size = this->eh_frame_section_->data_size();
313 const unsigned char* eh_frame_contents = of->get_input_view(eh_frame_offset,
316 for (Fde_offsets::const_iterator p = fde_offsets->begin();
317 p != fde_offsets->end();
320 typename elfcpp::Elf_types<size>::Elf_Addr fde_pc;
321 fde_pc = this->get_fde_pc<size, big_endian>(eh_frame_address,
323 p->first, p->second);
324 fde_addresses->push_back(fde_pc, eh_frame_address + p->first);
327 of->free_input_view(eh_frame_offset, eh_frame_size, eh_frame_contents);
332 // Write the FDE to OVIEW starting at OFFSET. CIE_OFFSET is the
333 // offset of the CIE in OVIEW. FDE_ENCODING is the encoding, from the
334 // CIE. ADDRALIGN is the required alignment. ADDRESS is the virtual
335 // address of OVIEW. Record the FDE pc for EH_FRAME_HDR. Return the
338 template<int size, bool big_endian>
340 Fde::write(unsigned char* oview, section_offset_type offset,
341 uint64_t address, unsigned int addralign,
342 section_offset_type cie_offset, unsigned char fde_encoding,
343 Eh_frame_hdr* eh_frame_hdr)
345 gold_assert((offset & (addralign - 1)) == 0);
347 size_t length = this->contents_.length();
349 // We add 8 when getting the aligned length to account for the
350 // length word and the CIE offset.
351 size_t aligned_full_length = align_address(length + 8, addralign);
353 // Write the length of the FDE as a 32-bit word. The length word
354 // does not include the four bytes of the length word itself, but it
355 // does include the offset to the CIE.
356 elfcpp::Swap<32, big_endian>::writeval(oview + offset,
357 aligned_full_length - 4);
359 // Write the offset to the CIE as a 32-bit word. This is the
360 // difference between the address of the offset word itself and the
362 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 4,
363 offset + 4 - cie_offset);
365 // Copy the rest of the FDE. Note that this is run before
366 // relocation processing is done on this section, so the relocations
367 // will later be applied to the FDE data.
368 memcpy(oview + offset + 8, this->contents_.data(), length);
370 // If this FDE is associated with a PLT, fill in the PLT's address
372 if (this->object_ == NULL)
374 gold_assert(memcmp(oview + offset + 8, "\0\0\0\0\0\0\0\0", 8) == 0);
377 parameters->target().plt_fde_location(this->u_.from_linker.plt,
380 uint64_t poffset = paddress - (address + offset + 8);
381 int32_t spoffset = static_cast<int32_t>(poffset);
382 uint32_t upsize = static_cast<uint32_t>(psize);
383 if (static_cast<uint64_t>(static_cast<int64_t>(spoffset)) != poffset
384 || static_cast<off_t>(upsize) != psize)
385 gold_warning(_("overflow in PLT unwind data; "
386 "unwinding through PLT may fail"));
387 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 8, spoffset);
388 elfcpp::Swap<32, big_endian>::writeval(oview + offset + 12, upsize);
391 if (aligned_full_length > length + 8)
392 memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
394 // Tell the exception frame header about this FDE.
395 if (eh_frame_hdr != NULL)
396 eh_frame_hdr->record_fde(offset, fde_encoding);
398 return offset + aligned_full_length;
407 for (std::vector<Fde*>::iterator p = this->fdes_.begin();
408 p != this->fdes_.end();
413 // Set the output offset of a CIE. Return the new output offset.
416 Cie::set_output_offset(section_offset_type output_offset,
417 unsigned int addralign,
418 Merge_map* merge_map)
420 size_t length = this->contents_.length();
422 // Add 4 for length and 4 for zero CIE identifier tag.
425 if (this->object_ != NULL)
427 // Add a mapping so that relocations are applied correctly.
428 merge_map->add_mapping(this->object_, this->shndx_, this->input_offset_,
429 length, output_offset);
432 length = align_address(length, addralign);
434 for (std::vector<Fde*>::const_iterator p = this->fdes_.begin();
435 p != this->fdes_.end();
438 (*p)->add_mapping(output_offset + length, merge_map);
440 size_t fde_length = (*p)->length();
441 fde_length = align_address(fde_length, addralign);
442 length += fde_length;
445 return output_offset + length;
448 // Write the CIE to OVIEW starting at OFFSET. Round up the bytes to
449 // ADDRALIGN. ADDRESS is the virtual address of OVIEW.
450 // EH_FRAME_HDR is the exception frame header for FDE recording.
451 // POST_FDES stashes FDEs created after mappings were done, for later
452 // writing. Return the new offset.
454 template<int size, bool big_endian>
456 Cie::write(unsigned char* oview, section_offset_type offset,
457 uint64_t address, unsigned int addralign,
458 Eh_frame_hdr* eh_frame_hdr, Post_fdes* post_fdes)
460 gold_assert((offset & (addralign - 1)) == 0);
462 section_offset_type cie_offset = offset;
464 size_t length = this->contents_.length();
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);
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);
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);
478 // Write out the CIE data.
479 memcpy(oview + offset + 8, this->contents_.data(), length);
481 if (aligned_full_length > length + 8)
482 memset(oview + offset + length + 8, 0, aligned_full_length - (length + 8));
484 offset += aligned_full_length;
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();
492 if ((*p)->post_map())
493 post_fdes->push_back(Post_fde(*p, cie_offset, fde_encoding));
495 offset = (*p)->write<size, big_endian>(oview, offset, address,
496 addralign, cie_offset,
497 fde_encoding, eh_frame_hdr);
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.
509 // An equality operator for Cie.
512 operator==(const Cie& cie1, const Cie& cie2)
514 return (cie1.personality_name_ == cie2.personality_name_
515 && cie1.contents_ == cie2.contents_);
518 // A less-than operator for Cie.
521 operator<(const Cie& cie1, const Cie& cie2)
523 if (cie1.personality_name_ != cie2.personality_name_)
524 return cie1.personality_name_ < cie2.personality_name_;
525 return cie1.contents_ < cie2.contents_;
531 : Output_section_data(Output_data::default_alignment()),
534 unmergeable_cie_offsets_(),
536 mappings_are_done_(false),
541 // Skip an LEB128, updating *PP to point to the next character.
542 // Return false if we ran off the end of the string.
545 Eh_frame::skip_leb128(const unsigned char** pp, const unsigned char* pend)
547 const unsigned char* p;
548 for (p = *pp; p < pend; ++p)
550 if ((*p & 0x80) == 0)
559 // Add input section SHNDX in OBJECT to an exception frame section.
560 // SYMBOLS is the contents of the symbol table section (size
561 // SYMBOLS_SIZE), SYMBOL_NAMES is the symbol names section (size
562 // SYMBOL_NAMES_SIZE). RELOC_SHNDX is the index of a relocation
563 // section applying to SHNDX, or 0 if none, or -1U if more than one.
564 // RELOC_TYPE is the type of the reloc section if there is one, either
565 // SHT_REL or SHT_RELA. We try to parse the input exception frame
566 // data into our data structures. If we can't do it, we return false
567 // to mean that the section should be handled as a normal input
570 template<int size, bool big_endian>
572 Eh_frame::add_ehframe_input_section(
573 Sized_relobj_file<size, big_endian>* object,
574 const unsigned char* symbols,
575 section_size_type symbols_size,
576 const unsigned char* symbol_names,
577 section_size_type symbol_names_size,
579 unsigned int reloc_shndx,
580 unsigned int reloc_type)
582 // Get the section contents.
583 section_size_type contents_len;
584 const unsigned char* pcontents = object->section_contents(shndx,
587 if (contents_len == 0)
590 // If this is the marker section for the end of the data, then
591 // return false to force it to be handled as an ordinary input
592 // section. If we don't do this, we won't correctly handle the case
593 // of unrecognized .eh_frame sections.
594 if (contents_len == 4
595 && elfcpp::Swap<32, big_endian>::readval(pcontents) == 0)
599 if (!this->do_add_ehframe_input_section(object, symbols, symbols_size,
600 symbol_names, symbol_names_size,
602 reloc_type, pcontents,
603 contents_len, &new_cies))
605 if (this->eh_frame_hdr_ != NULL)
606 this->eh_frame_hdr_->found_unrecognized_eh_frame_section();
608 for (New_cies::iterator p = new_cies.begin();
616 // Now that we know we are using this section, record any new CIEs
618 for (New_cies::const_iterator p = new_cies.begin();
623 this->cie_offsets_.insert(p->first);
625 this->unmergeable_cie_offsets_.push_back(p->first);
631 // The bulk of the implementation of add_ehframe_input_section.
633 template<int size, bool big_endian>
635 Eh_frame::do_add_ehframe_input_section(
636 Sized_relobj_file<size, big_endian>* object,
637 const unsigned char* symbols,
638 section_size_type symbols_size,
639 const unsigned char* symbol_names,
640 section_size_type symbol_names_size,
642 unsigned int reloc_shndx,
643 unsigned int reloc_type,
644 const unsigned char* pcontents,
645 section_size_type contents_len,
648 Track_relocs<size, big_endian> relocs;
650 const unsigned char* p = pcontents;
651 const unsigned char* pend = p + contents_len;
653 // Get the contents of the reloc section if any.
654 if (!relocs.initialize(object, reloc_shndx, reloc_type))
657 // Keep track of which CIEs are at which offsets.
665 // There shouldn't be any relocations here.
666 if (relocs.advance(p + 4 - pcontents) > 0)
669 unsigned int len = elfcpp::Swap<32, big_endian>::readval(p);
673 // We should only find a zero-length entry at the end of the
679 // We don't support a 64-bit .eh_frame.
680 if (len == 0xffffffff)
682 if (static_cast<unsigned int>(pend - p) < len)
685 const unsigned char* const pentend = p + len;
689 if (relocs.advance(p + 4 - pcontents) > 0)
692 unsigned int id = elfcpp::Swap<32, big_endian>::readval(p);
698 if (!this->read_cie(object, shndx, symbols, symbols_size,
699 symbol_names, symbol_names_size,
700 pcontents, p, pentend, &relocs, &cies,
707 if (!this->read_fde(object, shndx, symbols, symbols_size,
708 pcontents, id, p, pentend, &relocs, &cies))
718 // Read a CIE. Return false if we can't parse the information.
720 template<int size, bool big_endian>
722 Eh_frame::read_cie(Sized_relobj_file<size, big_endian>* object,
724 const unsigned char* symbols,
725 section_size_type symbols_size,
726 const unsigned char* symbol_names,
727 section_size_type symbol_names_size,
728 const unsigned char* pcontents,
729 const unsigned char* pcie,
730 const unsigned char* pcieend,
731 Track_relocs<size, big_endian>* relocs,
732 Offsets_to_cie* cies,
735 bool mergeable = true;
737 // We need to find the personality routine if there is one, since we
738 // can only merge CIEs which use the same routine. We also need to
739 // find the FDE encoding if there is one, so that we can read the PC
742 const unsigned char* p = pcie;
746 unsigned char version = *p++;
747 if (version != 1 && version != 3)
750 const unsigned char* paug = p;
751 const void* paugendv = memchr(p, '\0', pcieend - p);
752 const unsigned char* paugend = static_cast<const unsigned char*>(paugendv);
757 if (paug[0] == 'e' && paug[1] == 'h')
759 // This is a CIE from gcc before version 3.0. We can't merge
760 // these. We can still read the FDEs.
765 if (pcieend - p < size / 8)
770 // Skip the code alignment.
771 if (!skip_leb128(&p, pcieend))
774 // Skip the data alignment.
775 if (!skip_leb128(&p, pcieend))
778 // Skip the return column.
787 if (!skip_leb128(&p, pcieend))
794 // Skip the augmentation size.
795 if (!skip_leb128(&p, pcieend))
799 unsigned char fde_encoding = elfcpp::DW_EH_PE_absptr;
801 while (*paug != '\0')
805 case 'L': // LSDA encoding.
811 case 'R': // FDE encoding.
815 switch (fde_encoding & 7)
817 case elfcpp::DW_EH_PE_absptr:
818 case elfcpp::DW_EH_PE_udata2:
819 case elfcpp::DW_EH_PE_udata4:
820 case elfcpp::DW_EH_PE_udata8:
823 // We don't expect to see any other cases here, and
824 // we're not prepared to handle them.
834 // Personality encoding.
838 unsigned char per_encoding = *p;
841 if ((per_encoding & 0x60) == 0x60)
843 unsigned int per_width;
844 switch (per_encoding & 7)
846 case elfcpp::DW_EH_PE_udata2:
849 case elfcpp::DW_EH_PE_udata4:
852 case elfcpp::DW_EH_PE_udata8:
855 case elfcpp::DW_EH_PE_absptr:
856 per_width = size / 8;
862 if ((per_encoding & 0xf0) == elfcpp::DW_EH_PE_aligned)
864 unsigned int len = p - pcie;
865 len += per_width - 1;
866 len &= ~ (per_width - 1);
867 if (static_cast<unsigned int>(pcieend - p) < len)
872 per_offset = p - pcontents;
874 if (static_cast<unsigned int>(pcieend - p) < per_width)
887 const char* personality_name = "";
888 if (per_offset != -1)
890 if (relocs->advance(per_offset) > 0)
892 if (relocs->next_offset() != per_offset)
895 unsigned int personality_symndx = relocs->next_symndx();
896 if (personality_symndx == -1U)
899 if (personality_symndx < object->local_symbol_count())
901 // We can only merge this CIE if the personality routine is
902 // a global symbol. We can still read the FDEs.
907 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
908 if (personality_symndx >= symbols_size / sym_size)
910 elfcpp::Sym<size, big_endian> sym(symbols
911 + (personality_symndx * sym_size));
912 unsigned int name_offset = sym.get_st_name();
913 if (name_offset >= symbol_names_size)
915 personality_name = (reinterpret_cast<const char*>(symbol_names)
919 int r = relocs->advance(per_offset + 1);
923 if (relocs->advance(pcieend - pcontents) > 0)
926 Cie cie(object, shndx, (pcie - 8) - pcontents, fde_encoding,
927 personality_name, pcie, pcieend - pcie);
928 Cie* cie_pointer = NULL;
931 Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
932 if (find_cie != this->cie_offsets_.end())
933 cie_pointer = *find_cie;
936 // See if we already saw this CIE in this object file.
937 for (New_cies::const_iterator pc = new_cies->begin();
938 pc != new_cies->end();
941 if (*(pc->first) == cie)
943 cie_pointer = pc->first;
950 if (cie_pointer == NULL)
952 cie_pointer = new Cie(cie);
953 new_cies->push_back(std::make_pair(cie_pointer, mergeable));
957 // We are deleting this CIE. Record that in our mapping from
958 // input sections to the output section. At this point we don't
959 // know for sure that we are doing a special mapping for this
960 // input section, but that's OK--if we don't do a special
961 // mapping, nobody will ever ask for the mapping we add here.
962 this->merge_map_.add_mapping(object, shndx, (pcie - 8) - pcontents,
963 pcieend - (pcie - 8), -1);
966 // Record this CIE plus the offset in the input section.
967 cies->insert(std::make_pair(pcie - pcontents, cie_pointer));
972 // Read an FDE. Return false if we can't parse the information.
974 template<int size, bool big_endian>
976 Eh_frame::read_fde(Sized_relobj_file<size, big_endian>* object,
978 const unsigned char* symbols,
979 section_size_type symbols_size,
980 const unsigned char* pcontents,
982 const unsigned char* pfde,
983 const unsigned char* pfdeend,
984 Track_relocs<size, big_endian>* relocs,
985 Offsets_to_cie* cies)
987 // OFFSET is the distance between the 4 bytes before PFDE to the
988 // start of the CIE. The offset we recorded for the CIE is 8 bytes
989 // after the start of the CIE--after the length and the zero tag.
990 unsigned int cie_offset = (pfde - 4 - pcontents) - offset + 8;
991 Offsets_to_cie::const_iterator pcie = cies->find(cie_offset);
992 if (pcie == cies->end())
994 Cie* cie = pcie->second;
996 // The FDE should start with a reloc to the start of the code which
998 if (relocs->advance(pfde - pcontents) > 0)
1001 if (relocs->next_offset() != pfde - pcontents)
1004 unsigned int symndx = relocs->next_symndx();
1008 // There can be another reloc in the FDE, if the CIE specifies an
1009 // LSDA (language specific data area). We currently don't care. We
1010 // will care later if we want to optimize the LSDA from an absolute
1011 // pointer to a PC relative offset when generating a shared library.
1012 relocs->advance(pfdeend - pcontents);
1014 unsigned int fde_shndx;
1015 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1016 if (symndx >= symbols_size / sym_size)
1018 elfcpp::Sym<size, big_endian> sym(symbols + symndx * sym_size);
1020 fde_shndx = object->adjust_sym_shndx(symndx, sym.get_st_shndx(),
1024 && fde_shndx != elfcpp::SHN_UNDEF
1025 && fde_shndx < object->shnum()
1026 && !object->is_section_included(fde_shndx))
1028 // This FDE applies to a section which we are discarding. We
1029 // can discard this FDE.
1030 this->merge_map_.add_mapping(object, shndx, (pfde - 8) - pcontents,
1031 pfdeend - (pfde - 8), -1);
1035 cie->add_fde(new Fde(object, shndx, (pfde - 8) - pcontents,
1036 pfde, pfdeend - pfde));
1041 // Add unwind information for a PLT.
1044 Eh_frame::add_ehframe_for_plt(Output_data* plt, const unsigned char* cie_data,
1045 size_t cie_length, const unsigned char* fde_data,
1048 Cie cie(NULL, 0, 0, elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4, "",
1049 cie_data, cie_length);
1050 Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
1052 if (find_cie != this->cie_offsets_.end())
1056 gold_assert(!this->mappings_are_done_);
1057 pcie = new Cie(cie);
1058 this->cie_offsets_.insert(pcie);
1061 Fde* fde = new Fde(plt, fde_data, fde_length, this->mappings_are_done_);
1064 if (this->mappings_are_done_)
1065 this->final_data_size_ += align_address(fde_length + 8, this->addralign());
1068 // Return the number of FDEs.
1071 Eh_frame::fde_count() const
1073 unsigned int ret = 0;
1074 for (Unmergeable_cie_offsets::const_iterator p =
1075 this->unmergeable_cie_offsets_.begin();
1076 p != this->unmergeable_cie_offsets_.end();
1078 ret += (*p)->fde_count();
1079 for (Cie_offsets::const_iterator p = this->cie_offsets_.begin();
1080 p != this->cie_offsets_.end();
1082 ret += (*p)->fde_count();
1086 // Set the final data size.
1089 Eh_frame::set_final_data_size()
1091 // We can be called more than once if Layout::set_segment_offsets
1092 // finds a better mapping. We don't want to add all the mappings
1094 if (this->mappings_are_done_)
1096 this->set_data_size(this->final_data_size_);
1100 section_offset_type output_offset = 0;
1102 for (Unmergeable_cie_offsets::iterator p =
1103 this->unmergeable_cie_offsets_.begin();
1104 p != this->unmergeable_cie_offsets_.end();
1106 output_offset = (*p)->set_output_offset(output_offset,
1110 for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1111 p != this->cie_offsets_.end();
1113 output_offset = (*p)->set_output_offset(output_offset,
1117 this->mappings_are_done_ = true;
1118 this->final_data_size_ = output_offset;
1120 gold_assert((output_offset & (this->addralign() - 1)) == 0);
1121 this->set_data_size(output_offset);
1124 // Return an output offset for an input offset.
1127 Eh_frame::do_output_offset(const Relobj* object, unsigned int shndx,
1128 section_offset_type offset,
1129 section_offset_type* poutput) const
1131 return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
1134 // Return whether this is the merge section for an input section.
1137 Eh_frame::do_is_merge_section_for(const Relobj* object,
1138 unsigned int shndx) const
1140 return this->merge_map_.is_merge_section_for(object, shndx);
1143 // Write the data to the output file.
1146 Eh_frame::do_write(Output_file* of)
1148 const off_t offset = this->offset();
1149 const off_t oview_size = this->data_size();
1150 unsigned char* const oview = of->get_output_view(offset, oview_size);
1152 switch (parameters->size_and_endianness())
1154 #ifdef HAVE_TARGET_32_LITTLE
1155 case Parameters::TARGET_32_LITTLE:
1156 this->do_sized_write<32, false>(oview);
1159 #ifdef HAVE_TARGET_32_BIG
1160 case Parameters::TARGET_32_BIG:
1161 this->do_sized_write<32, true>(oview);
1164 #ifdef HAVE_TARGET_64_LITTLE
1165 case Parameters::TARGET_64_LITTLE:
1166 this->do_sized_write<64, false>(oview);
1169 #ifdef HAVE_TARGET_64_BIG
1170 case Parameters::TARGET_64_BIG:
1171 this->do_sized_write<64, true>(oview);
1178 of->write_output_view(offset, oview_size, oview);
1181 // Write the data to the output file--template version.
1183 template<int size, bool big_endian>
1185 Eh_frame::do_sized_write(unsigned char* oview)
1187 uint64_t address = this->address();
1188 unsigned int addralign = this->addralign();
1189 section_offset_type o = 0;
1190 Post_fdes post_fdes;
1191 for (Unmergeable_cie_offsets::iterator p =
1192 this->unmergeable_cie_offsets_.begin();
1193 p != this->unmergeable_cie_offsets_.end();
1195 o = (*p)->write<size, big_endian>(oview, o, address, addralign,
1196 this->eh_frame_hdr_, &post_fdes);
1197 for (Cie_offsets::iterator p = this->cie_offsets_.begin();
1198 p != this->cie_offsets_.end();
1200 o = (*p)->write<size, big_endian>(oview, o, address, addralign,
1201 this->eh_frame_hdr_, &post_fdes);
1202 for (Post_fdes::iterator p = post_fdes.begin();
1203 p != post_fdes.end();
1205 o = (*p).fde->write<size, big_endian>(oview, o, address, addralign,
1208 this->eh_frame_hdr_);
1211 #ifdef HAVE_TARGET_32_LITTLE
1214 Eh_frame::add_ehframe_input_section<32, false>(
1215 Sized_relobj_file<32, false>* object,
1216 const unsigned char* symbols,
1217 section_size_type symbols_size,
1218 const unsigned char* symbol_names,
1219 section_size_type symbol_names_size,
1221 unsigned int reloc_shndx,
1222 unsigned int reloc_type);
1225 #ifdef HAVE_TARGET_32_BIG
1228 Eh_frame::add_ehframe_input_section<32, true>(
1229 Sized_relobj_file<32, true>* object,
1230 const unsigned char* symbols,
1231 section_size_type symbols_size,
1232 const unsigned char* symbol_names,
1233 section_size_type symbol_names_size,
1235 unsigned int reloc_shndx,
1236 unsigned int reloc_type);
1239 #ifdef HAVE_TARGET_64_LITTLE
1242 Eh_frame::add_ehframe_input_section<64, false>(
1243 Sized_relobj_file<64, false>* object,
1244 const unsigned char* symbols,
1245 section_size_type symbols_size,
1246 const unsigned char* symbol_names,
1247 section_size_type symbol_names_size,
1249 unsigned int reloc_shndx,
1250 unsigned int reloc_type);
1253 #ifdef HAVE_TARGET_64_BIG
1256 Eh_frame::add_ehframe_input_section<64, true>(
1257 Sized_relobj_file<64, true>* object,
1258 const unsigned char* symbols,
1259 section_size_type symbols_size,
1260 const unsigned char* symbol_names,
1261 section_size_type symbol_names_size,
1263 unsigned int reloc_shndx,
1264 unsigned int reloc_type);
1267 } // End namespace gold.