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 final address and size of the exception frame header.
94 Eh_frame_hdr::do_set_address(uint64_t, off_t
)
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(const unsigned char* eh_frame_contents
,
238 off_t fde_offset
, unsigned char fde_encoding
)
240 // The FDE starts with a 4 byte length and a 4 byte offset to the
241 // CIE. The PC follows.
242 const unsigned char* p
= eh_frame_contents
+ fde_offset
+ 8;
244 typename
elfcpp::Elf_types
<size
>::Elf_Addr pc
;
245 bool is_signed
= (fde_encoding
& elfcpp::DW_EH_PE_signed
) != 0;
246 int pc_size
= fde_encoding
& 7;
247 if (pc_size
== elfcpp::DW_EH_PE_absptr
)
250 pc_size
= elfcpp::DW_EH_PE_udata4
;
252 pc_size
= elfcpp::DW_EH_PE_udata8
;
259 case elfcpp::DW_EH_PE_udata2
:
260 pc
= elfcpp::Swap
<16, big_endian
>::readval(p
);
262 pc
= (pc
^ 0x8000) - 0x8000;
265 case elfcpp::DW_EH_PE_udata4
:
266 pc
= elfcpp::Swap
<32, big_endian
>::readval(p
);
267 if (size
> 32 && is_signed
)
268 pc
= (pc
^ 0x80000000) - 0x80000000;
271 case elfcpp::DW_EH_PE_udata8
:
272 gold_assert(size
== 64);
273 pc
= elfcpp::Swap_unaligned
<64, big_endian
>::readval(p
);
283 // Given an array of FDE offsets in the .eh_frame section, return an
284 // array of offsets from the exception frame header to the FDE's
285 // output PC and to the output address of the FDE itself. We get the
286 // FDE's PC by actually looking in the .eh_frame section we just wrote
287 // to the output file.
289 template<int size
, bool big_endian
>
291 Eh_frame_hdr::get_fde_addresses(Output_file
* of
,
292 const Fde_offsets
* fde_offsets
,
293 Fde_addresses
<size
>* fde_addresses
)
295 typename
elfcpp::Elf_types
<size
>::Elf_Addr eh_frame_address
;
296 eh_frame_address
= this->eh_frame_section_
->address();
297 off_t eh_frame_offset
= this->eh_frame_section_
->offset();
298 off_t eh_frame_size
= this->eh_frame_section_
->data_size();
299 const unsigned char* eh_frame_contents
= of
->get_input_view(eh_frame_offset
,
302 for (Fde_offsets::const_iterator p
= fde_offsets
->begin();
303 p
!= fde_offsets
->end();
306 typename
elfcpp::Elf_types
<size
>::Elf_Addr fde_pc
;
307 fde_pc
= this->get_fde_pc
<size
, big_endian
>(eh_frame_contents
,
308 p
->first
, p
->second
);
309 fde_addresses
->push_back(fde_pc
, eh_frame_address
+ p
->first
);
312 of
->free_input_view(eh_frame_offset
, eh_frame_size
, eh_frame_contents
);
317 // Write the FDE to OVIEW starting at OFFSET. CIE_OFFSET is the
318 // offset of the CIE in OVIEW. FDE_ENCODING is the encoding, from the
319 // CIE. Record the FDE pc for EH_FRAME_HDR. Return the new offset.
321 template<int size
, bool big_endian
>
323 Fde::write(unsigned char* oview
, off_t offset
, off_t cie_offset
,
324 unsigned char fde_encoding
, Eh_frame_hdr
* eh_frame_hdr
)
326 size_t length
= this->contents_
.length();
328 // Write the length of the FDE as a 32-bit word. The length word
329 // does not include the four bytes of the length word itself, but it
330 // does include the offset to the CIE.
331 elfcpp::Swap
<32, big_endian
>::writeval(oview
+ offset
,
334 // Write the offset to the CIE as a 32-bit word. This is the
335 // difference between the address of the offset word itself and the
337 elfcpp::Swap
<32, big_endian
>::writeval(oview
+ offset
+ 4,
338 offset
+ 4 - cie_offset
);
340 // Copy the rest of the FDE. Note that this is run before
341 // relocation processing is done on this section, so the relocations
342 // will later be applied to the FDE data.
343 memcpy(oview
+ offset
+ 8, this->contents_
.data(), length
);
345 // Tell the exception frame header about this FDE.
346 if (eh_frame_hdr
!= NULL
)
347 eh_frame_hdr
->record_fde(offset
, fde_encoding
);
349 return offset
+ length
+ 8;
358 for (std::vector
<Fde
*>::iterator p
= this->fdes_
.begin();
359 p
!= this->fdes_
.end();
364 // Set the output offset of a CIE. Return the new output offset.
367 Cie::set_output_offset(off_t output_offset
, unsigned int addralign
,
368 Merge_map
* merge_map
)
370 size_t length
= this->contents_
.length();
371 gold_assert((length
& (addralign
- 1)) == 0);
372 // Add 4 for length and 4 for zero CIE identifier tag.
375 merge_map
->add_mapping(this->object_
, this->shndx_
, this->input_offset_
,
376 length
, output_offset
);
378 for (std::vector
<Fde
*>::const_iterator p
= this->fdes_
.begin();
379 p
!= this->fdes_
.end();
382 (*p
)->add_mapping(output_offset
+ length
, merge_map
);
384 size_t fde_length
= (*p
)->length();
385 gold_assert((fde_length
& (addralign
- 1)) == 0);
386 length
+= fde_length
;
389 return output_offset
+ length
;
392 // Write the CIE to OVIEW starting at OFFSET. EH_FRAME_HDR is for FDE
393 // recording. Return the new offset.
395 template<int size
, bool big_endian
>
397 Cie::write(unsigned char* oview
, off_t offset
, Eh_frame_hdr
* eh_frame_hdr
)
399 off_t cie_offset
= offset
;
401 size_t length
= this->contents_
.length();
403 // Write the length of the CIE as a 32-bit word. The length word
404 // does not include the four bytes of the length word itself.
405 elfcpp::Swap
<32, big_endian
>::writeval(oview
+ offset
, length
+ 4);
407 // Write the tag which marks this as a CIE: a 32-bit zero.
408 elfcpp::Swap
<32, big_endian
>::writeval(oview
+ offset
+ 4, 0);
410 // Write out the CIE data.
411 memcpy(oview
+ offset
+ 8, this->contents_
.data(), length
);
412 offset
+= length
+ 8;
414 // Write out the associated FDEs.
415 unsigned char fde_encoding
= this->fde_encoding_
;
416 for (std::vector
<Fde
*>::const_iterator p
= this->fdes_
.begin();
417 p
!= this->fdes_
.end();
419 offset
= (*p
)->write
<size
, big_endian
>(oview
, offset
, cie_offset
,
420 fde_encoding
, eh_frame_hdr
);
425 // We track all the CIEs we see, and merge them when possible. This
426 // works because each FDE holds an offset to the relevant CIE: we
427 // rewrite the FDEs to point to the merged CIE. This is worthwhile
428 // because in a typical C++ program many FDEs in many different object
429 // files will use the same CIE.
431 // An equality operator for Cie.
434 operator==(const Cie
& cie1
, const Cie
& cie2
)
436 return (cie1
.personality_name_
== cie2
.personality_name_
437 && cie1
.contents_
== cie2
.contents_
);
440 // A less-than operator for Cie.
443 operator<(const Cie
& cie1
, const Cie
& cie2
)
445 if (cie1
.personality_name_
!= cie2
.personality_name_
)
446 return cie1
.personality_name_
< cie2
.personality_name_
;
447 return cie1
.contents_
< cie2
.contents_
;
453 : Output_section_data(Output_data::default_alignment()),
456 unmergeable_cie_offsets_(),
461 // Skip an LEB128, updating *PP to point to the next character.
462 // Return false if we ran off the end of the string.
465 Eh_frame::skip_leb128(const unsigned char** pp
, const unsigned char* pend
)
467 const unsigned char* p
;
468 for (p
= *pp
; p
< pend
; ++p
)
470 if ((*p
& 0x80) == 0)
479 // Add input section SHNDX in OBJECT to an exception frame section.
480 // SYMBOLS is the contents of the symbol table section (size
481 // SYMBOLS_SIZE), SYMBOL_NAMES is the symbol names section (size
482 // SYMBOL_NAMES_SIZE). RELOC_SHNDX is the index of a relocation
483 // section applying to SHNDX, or 0 if none, or -1U if more than one.
484 // RELOC_TYPE is the type of the reloc section if there is one, either
485 // SHT_REL or SHT_RELA. We try to parse the input exception frame
486 // data into our data structures. If we can't do it, we return false
487 // to mean that the section should be handled as a normal input
490 template<int size
, bool big_endian
>
492 Eh_frame::add_ehframe_input_section(
493 Sized_relobj
<size
, big_endian
>* object
,
494 const unsigned char* symbols
,
496 const unsigned char* symbol_names
,
497 off_t symbol_names_size
,
499 unsigned int reloc_shndx
,
500 unsigned int reloc_type
)
502 // Get the section contents.
504 const unsigned char* pcontents
= object
->section_contents(shndx
,
507 if (contents_len
== 0)
510 // If this is the marker section for the end of the data, then
511 // return false to force it to be handled as an ordinary input
512 // section. If we don't do this, we won't correctly handle the case
513 // of unrecognized .eh_frame sections.
514 if (contents_len
== 4
515 && elfcpp::Swap
<32, big_endian
>::readval(pcontents
) == 0)
519 if (!this->do_add_ehframe_input_section(object
, symbols
, symbols_size
,
520 symbol_names
, symbol_names_size
,
522 reloc_type
, pcontents
,
523 contents_len
, &new_cies
))
525 this->eh_frame_hdr_
->found_unrecognized_eh_frame_section();
527 for (New_cies::iterator p
= new_cies
.begin();
535 // Now that we know we are using this section, record any new CIEs
537 for (New_cies::const_iterator p
= new_cies
.begin();
543 this->cie_offsets_
.insert(std::make_pair(p
->first
, zero
));
545 this->unmergeable_cie_offsets_
.push_back(std::make_pair(p
->first
,
552 // The bulk of the implementation of add_ehframe_input_section.
554 template<int size
, bool big_endian
>
556 Eh_frame::do_add_ehframe_input_section(
557 Sized_relobj
<size
, big_endian
>* object
,
558 const unsigned char* symbols
,
560 const unsigned char* symbol_names
,
561 off_t symbol_names_size
,
563 unsigned int reloc_shndx
,
564 unsigned int reloc_type
,
565 const unsigned char* pcontents
,
569 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
570 Track_relocs
<size
, big_endian
> relocs
;
572 const unsigned char* p
= pcontents
;
573 const unsigned char* pend
= p
+ contents_len
;
575 // Get the contents of the reloc section if any.
576 if (!relocs
.initialize(object
, reloc_shndx
, reloc_type
))
579 // Keep track of which CIEs are at which offsets.
587 // There shouldn't be any relocations here.
588 if (relocs
.advance(p
+ 4 - pcontents
) > 0)
591 unsigned int len
= elfcpp::Swap
<32, big_endian
>::readval(p
);
595 // We should only find a zero-length entry at the end of the
601 // We don't support a 64-bit .eh_frame.
602 if (len
== 0xffffffff)
604 if (static_cast<unsigned int>(pend
- p
) < len
)
607 const unsigned char* const pentend
= p
+ len
;
611 if (relocs
.advance(p
+ 4 - pcontents
) > 0)
614 unsigned int id
= elfcpp::Swap
<32, big_endian
>::readval(p
);
620 if (!this->read_cie(object
, shndx
, symbols
, symbols_size
,
621 symbol_names
, symbol_names_size
,
622 pcontents
, p
, pentend
, &relocs
, &cies
,
629 if (!this->read_fde(object
, shndx
, symbols
, symbols_size
,
630 pcontents
, id
, p
, pentend
, &relocs
, &cies
))
640 // Read a CIE. Return false if we can't parse the information.
642 template<int size
, bool big_endian
>
644 Eh_frame::read_cie(Sized_relobj
<size
, big_endian
>* object
,
646 const unsigned char* symbols
,
648 const unsigned char* symbol_names
,
649 off_t symbol_names_size
,
650 const unsigned char* pcontents
,
651 const unsigned char* pcie
,
652 const unsigned char *pcieend
,
653 Track_relocs
<size
, big_endian
>* relocs
,
654 Offsets_to_cie
* cies
,
657 bool mergeable
= true;
659 // We need to find the personality routine if there is one, since we
660 // can only merge CIEs which use the same routine. We also need to
661 // find the FDE encoding if there is one, so that we can read the PC
664 const unsigned char* p
= pcie
;
668 unsigned char version
= *p
++;
669 if (version
!= 1 && version
!= 3)
672 const unsigned char* paug
= p
;
673 const void* paugendv
= memchr(p
, '\0', pcieend
- p
);
674 const unsigned char* paugend
= static_cast<const unsigned char*>(paugendv
);
679 if (paug
[0] == 'e' && paug
[1] == 'h')
681 // This is a CIE from gcc before version 3.0. We can't merge
682 // these. We can still read the FDEs.
687 if (pcieend
- p
< size
/ 8)
692 // Skip the code alignment.
693 if (!skip_leb128(&p
, pcieend
))
696 // Skip the data alignment.
697 if (!skip_leb128(&p
, pcieend
))
700 // Skip the return column.
709 if (!skip_leb128(&p
, pcieend
))
716 // Skip the augmentation size.
717 if (!skip_leb128(&p
, pcieend
))
721 unsigned char fde_encoding
= elfcpp::DW_EH_PE_absptr
;
723 while (*paug
!= '\0')
727 case 'L': // LSDA encoding.
733 case 'R': // FDE encoding.
737 switch (fde_encoding
& 7)
739 case elfcpp::DW_EH_PE_absptr
:
740 case elfcpp::DW_EH_PE_udata2
:
741 case elfcpp::DW_EH_PE_udata4
:
742 case elfcpp::DW_EH_PE_udata8
:
754 // Personality encoding.
758 unsigned char per_encoding
= *p
;
761 if ((per_encoding
& 0x60) == 0x60)
763 unsigned int per_width
;
764 switch (per_encoding
& 7)
766 case elfcpp::DW_EH_PE_udata2
:
769 case elfcpp::DW_EH_PE_udata4
:
772 case elfcpp::DW_EH_PE_udata8
:
775 case elfcpp::DW_EH_PE_absptr
:
776 per_width
= size
/ 8;
782 if ((per_encoding
& 0xf0) == elfcpp::DW_EH_PE_aligned
)
784 unsigned int len
= p
- pcie
;
785 len
+= per_width
- 1;
786 len
&= ~ (per_width
- 1);
787 if (static_cast<unsigned int>(pcieend
- p
) < len
)
792 per_offset
= p
- pcontents
;
794 if (static_cast<unsigned int>(pcieend
- p
) < per_width
)
807 const char* personality_name
= "";
808 if (per_offset
!= -1)
810 if (relocs
->advance(per_offset
) > 0)
812 if (relocs
->next_offset() != per_offset
)
815 unsigned int personality_symndx
= relocs
->next_symndx();
816 if (personality_symndx
== -1U)
819 if (personality_symndx
< object
->local_symbol_count())
821 // We can only merge this CIE if the personality routine is
822 // a global symbol. We can still read the FDEs.
827 const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
828 if (personality_symndx
>= symbols_size
/ sym_size
)
830 elfcpp::Sym
<size
, big_endian
> sym(symbols
831 + (personality_symndx
* sym_size
));
832 unsigned int name_offset
= sym
.get_st_name();
833 if (name_offset
>= symbol_names_size
)
835 personality_name
= (reinterpret_cast<const char*>(symbol_names
)
839 int r
= relocs
->advance(per_offset
+ 1);
843 if (relocs
->advance(pcieend
- pcontents
) > 0)
846 Cie
cie(object
, shndx
, (pcie
- 8) - pcontents
, fde_encoding
,
847 personality_name
, pcie
, pcieend
- pcie
);
848 Cie
* cie_pointer
= NULL
;
851 Cie_offsets::iterator find_cie
= this->cie_offsets_
.find(&cie
);
852 if (find_cie
!= this->cie_offsets_
.end())
853 cie_pointer
= find_cie
->first
;
856 // See if we already saw this CIE in this object file.
857 for (New_cies::const_iterator pc
= new_cies
->begin();
858 pc
!= new_cies
->end();
861 if (*(pc
->first
) == cie
)
863 cie_pointer
= pc
->first
;
870 if (cie_pointer
== NULL
)
872 cie_pointer
= new Cie(cie
);
873 new_cies
->push_back(std::make_pair(cie_pointer
, mergeable
));
877 // We are deleting this CIE. Record that in our mapping from
878 // input sections to the output section. At this point we don't
879 // know for sure that we are doing a special mapping for this
880 // input section, but that's OK--if we don't do a special
881 // mapping, nobody will ever ask for the mapping we add here.
882 this->merge_map_
.add_mapping(object
, shndx
, (pcie
- 8) - pcontents
,
883 pcieend
- (pcie
- 8), -1);
886 // Record this CIE plus the offset in the input section.
887 cies
->insert(std::make_pair(pcie
- pcontents
, cie_pointer
));
892 // Read an FDE. Return false if we can't parse the information.
894 template<int size
, bool big_endian
>
896 Eh_frame::read_fde(Sized_relobj
<size
, big_endian
>* object
,
898 const unsigned char* symbols
,
900 const unsigned char* pcontents
,
902 const unsigned char* pfde
,
903 const unsigned char *pfdeend
,
904 Track_relocs
<size
, big_endian
>* relocs
,
905 Offsets_to_cie
* cies
)
907 // OFFSET is the distance between the 4 bytes before PFDE to the
908 // start of the CIE. The offset we recorded for the CIE is 8 bytes
909 // after the start of the CIE--after the length and the zero tag.
910 unsigned int cie_offset
= (pfde
- 4 - pcontents
) - offset
+ 8;
911 Offsets_to_cie::const_iterator pcie
= cies
->find(cie_offset
);
912 if (pcie
== cies
->end())
914 Cie
* cie
= pcie
->second
;
916 // The FDE should start with a reloc to the start of the code which
918 if (relocs
->advance(pfde
- pcontents
) > 0)
921 if (relocs
->next_offset() != pfde
- pcontents
)
924 unsigned int symndx
= relocs
->next_symndx();
928 // There can be another reloc in the FDE, if the CIE specifies an
929 // LSDA (language specific data area). We currently don't care. We
930 // will care later if we want to optimize the LSDA from an absolute
931 // pointer to a PC relative offset when generating a shared library.
932 relocs
->advance(pfdeend
- pcontents
);
934 unsigned int fde_shndx
;
935 const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
936 if (symndx
>= symbols_size
/ sym_size
)
938 elfcpp::Sym
<size
, big_endian
> sym(symbols
+ symndx
* sym_size
);
939 fde_shndx
= sym
.get_st_shndx();
941 if (fde_shndx
!= elfcpp::SHN_UNDEF
942 && fde_shndx
< object
->shnum()
943 && !object
->is_section_included(fde_shndx
))
945 // This FDE applies to a section which we are discarding. We
946 // can discard this FDE.
947 this->merge_map_
.add_mapping(object
, shndx
, (pfde
- 8) - pcontents
,
948 pfdeend
- (pfde
- 8), -1);
952 cie
->add_fde(new Fde(object
, shndx
, (pfde
- 8) - pcontents
,
953 pfde
, pfdeend
- pfde
));
958 // Return the number of FDEs.
961 Eh_frame::fde_count() const
963 unsigned int ret
= 0;
964 for (Unmergeable_cie_offsets::const_iterator p
=
965 this->unmergeable_cie_offsets_
.begin();
966 p
!= this->unmergeable_cie_offsets_
.end();
968 ret
+= p
->first
->fde_count();
969 for (Cie_offsets::const_iterator p
= this->cie_offsets_
.begin();
970 p
!= this->cie_offsets_
.end();
972 ret
+= p
->first
->fde_count();
976 // Set the final data size.
979 Eh_frame::do_set_address(uint64_t, off_t start_file_offset
)
981 off_t output_offset
= 0;
983 for (Unmergeable_cie_offsets::iterator p
=
984 this->unmergeable_cie_offsets_
.begin();
985 p
!= this->unmergeable_cie_offsets_
.end();
988 p
->second
= start_file_offset
+ output_offset
;
989 output_offset
= p
->first
->set_output_offset(output_offset
,
994 for (Cie_offsets::iterator p
= this->cie_offsets_
.begin();
995 p
!= this->cie_offsets_
.end();
998 p
->second
= start_file_offset
+ output_offset
;
999 output_offset
= p
->first
->set_output_offset(output_offset
,
1004 gold_assert((output_offset
& (this->addralign() - 1)) == 0);
1005 this->set_data_size(output_offset
);
1008 // Return an output offset for an input offset.
1011 Eh_frame::do_output_offset(const Relobj
* object
, unsigned int shndx
,
1012 off_t offset
, off_t
* poutput
) const
1014 return this->merge_map_
.get_output_offset(object
, shndx
, offset
, poutput
);
1017 // Write the data to the output file.
1020 Eh_frame::do_write(Output_file
* of
)
1022 const off_t offset
= this->offset();
1023 const off_t oview_size
= this->data_size();
1024 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
1026 if (parameters
->get_size() == 32)
1028 if (!parameters
->is_big_endian())
1030 #ifdef HAVE_TARGET_32_LITTLE
1031 this->do_sized_write
<32, false>(oview
);
1038 #ifdef HAVE_TARGET_32_BIG
1039 this->do_sized_write
<32, true>(oview
);
1045 else if (parameters
->get_size() == 64)
1047 if (!parameters
->is_big_endian())
1049 #ifdef HAVE_TARGET_64_LITTLE
1050 this->do_sized_write
<64, false>(oview
);
1057 #ifdef HAVE_TARGET_64_BIG
1058 this->do_sized_write
<64, true>(oview
);
1067 of
->write_output_view(offset
, oview_size
, oview
);
1070 // Write the data to the output file--template version.
1072 template<int size
, bool big_endian
>
1074 Eh_frame::do_sized_write(unsigned char* oview
)
1077 for (Unmergeable_cie_offsets::iterator p
=
1078 this->unmergeable_cie_offsets_
.begin();
1079 p
!= this->unmergeable_cie_offsets_
.end();
1081 o
= p
->first
->write
<size
, big_endian
>(oview
, o
, this->eh_frame_hdr_
);
1082 for (Cie_offsets::iterator p
= this->cie_offsets_
.begin();
1083 p
!= this->cie_offsets_
.end();
1085 o
= p
->first
->write
<size
, big_endian
>(oview
, o
, this->eh_frame_hdr_
);
1088 #ifdef HAVE_TARGET_32_LITTLE
1091 Eh_frame::add_ehframe_input_section
<32, false>(
1092 Sized_relobj
<32, false>* object
,
1093 const unsigned char* symbols
,
1095 const unsigned char* symbol_names
,
1096 off_t symbol_names_size
,
1098 unsigned int reloc_shndx
,
1099 unsigned int reloc_type
);
1102 #ifdef HAVE_TARGET_32_BIG
1105 Eh_frame::add_ehframe_input_section
<32, true>(
1106 Sized_relobj
<32, true>* object
,
1107 const unsigned char* symbols
,
1109 const unsigned char* symbol_names
,
1110 off_t symbol_names_size
,
1112 unsigned int reloc_shndx
,
1113 unsigned int reloc_type
);
1116 #ifdef HAVE_TARGET_64_LITTLE
1119 Eh_frame::add_ehframe_input_section
<64, false>(
1120 Sized_relobj
<64, false>* object
,
1121 const unsigned char* symbols
,
1123 const unsigned char* symbol_names
,
1124 off_t symbol_names_size
,
1126 unsigned int reloc_shndx
,
1127 unsigned int reloc_type
);
1130 #ifdef HAVE_TARGET_64_BIG
1133 Eh_frame::add_ehframe_input_section
<64, true>(
1134 Sized_relobj
<64, true>* object
,
1135 const unsigned char* symbols
,
1137 const unsigned char* symbol_names
,
1138 off_t symbol_names_size
,
1140 unsigned int reloc_shndx
,
1141 unsigned int reloc_type
);
1144 } // End namespace gold.