1 /* .eh_frame section optimization.
2 Copyright (C) 2001-2014 Free Software Foundation, Inc.
3 Written by Jakub Jelinek <jakub@redhat.com>.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
28 #define EH_FRAME_HDR_SIZE 8
34 unsigned char version
;
35 unsigned char local_personality
;
36 char augmentation
[20];
38 bfd_signed_vma data_align
;
40 bfd_vma augmentation_size
;
42 struct elf_link_hash_entry
*h
;
47 unsigned int reloc_index
;
49 struct eh_cie_fde
*cie_inf
;
50 unsigned char per_encoding
;
51 unsigned char lsda_encoding
;
52 unsigned char fde_encoding
;
53 unsigned char initial_insn_length
;
54 unsigned char can_make_lsda_relative
;
55 unsigned char initial_instructions
[50];
60 /* If *ITER hasn't reached END yet, read the next byte into *RESULT and
61 move onto the next byte. Return true on success. */
63 static inline bfd_boolean
64 read_byte (bfd_byte
**iter
, bfd_byte
*end
, unsigned char *result
)
68 *result
= *((*iter
)++);
72 /* Move *ITER over LENGTH bytes, or up to END, whichever is closer.
73 Return true it was possible to move LENGTH bytes. */
75 static inline bfd_boolean
76 skip_bytes (bfd_byte
**iter
, bfd_byte
*end
, bfd_size_type length
)
78 if ((bfd_size_type
) (end
- *iter
) < length
)
87 /* Move *ITER over an leb128, stopping at END. Return true if the end
88 of the leb128 was found. */
91 skip_leb128 (bfd_byte
**iter
, bfd_byte
*end
)
95 if (!read_byte (iter
, end
, &byte
))
101 /* Like skip_leb128, but treat the leb128 as an unsigned value and
102 store it in *VALUE. */
105 read_uleb128 (bfd_byte
**iter
, bfd_byte
*end
, bfd_vma
*value
)
110 if (!skip_leb128 (iter
, end
))
116 *value
= (*value
<< 7) | (*--p
& 0x7f);
121 /* Like read_uleb128, but for signed values. */
124 read_sleb128 (bfd_byte
**iter
, bfd_byte
*end
, bfd_signed_vma
*value
)
129 if (!skip_leb128 (iter
, end
))
133 *value
= ((*--p
& 0x7f) ^ 0x40) - 0x40;
135 *value
= (*value
<< 7) | (*--p
& 0x7f);
140 /* Return 0 if either encoding is variable width, or not yet known to bfd. */
143 int get_DW_EH_PE_width (int encoding
, int ptr_size
)
145 /* DW_EH_PE_ values of 0x60 and 0x70 weren't defined at the time .eh_frame
147 if ((encoding
& 0x60) == 0x60)
150 switch (encoding
& 7)
152 case DW_EH_PE_udata2
: return 2;
153 case DW_EH_PE_udata4
: return 4;
154 case DW_EH_PE_udata8
: return 8;
155 case DW_EH_PE_absptr
: return ptr_size
;
163 #define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0)
165 /* Read a width sized value from memory. */
168 read_value (bfd
*abfd
, bfd_byte
*buf
, int width
, int is_signed
)
176 value
= bfd_get_signed_16 (abfd
, buf
);
178 value
= bfd_get_16 (abfd
, buf
);
182 value
= bfd_get_signed_32 (abfd
, buf
);
184 value
= bfd_get_32 (abfd
, buf
);
188 value
= bfd_get_signed_64 (abfd
, buf
);
190 value
= bfd_get_64 (abfd
, buf
);
200 /* Store a width sized value to memory. */
203 write_value (bfd
*abfd
, bfd_byte
*buf
, bfd_vma value
, int width
)
207 case 2: bfd_put_16 (abfd
, value
, buf
); break;
208 case 4: bfd_put_32 (abfd
, value
, buf
); break;
209 case 8: bfd_put_64 (abfd
, value
, buf
); break;
210 default: BFD_FAIL ();
214 /* Return one if C1 and C2 CIEs can be merged. */
217 cie_eq (const void *e1
, const void *e2
)
219 const struct cie
*c1
= (const struct cie
*) e1
;
220 const struct cie
*c2
= (const struct cie
*) e2
;
222 if (c1
->hash
== c2
->hash
223 && c1
->length
== c2
->length
224 && c1
->version
== c2
->version
225 && c1
->local_personality
== c2
->local_personality
226 && strcmp (c1
->augmentation
, c2
->augmentation
) == 0
227 && strcmp (c1
->augmentation
, "eh") != 0
228 && c1
->code_align
== c2
->code_align
229 && c1
->data_align
== c2
->data_align
230 && c1
->ra_column
== c2
->ra_column
231 && c1
->augmentation_size
== c2
->augmentation_size
232 && memcmp (&c1
->personality
, &c2
->personality
,
233 sizeof (c1
->personality
)) == 0
234 && (c1
->cie_inf
->u
.cie
.u
.sec
->output_section
235 == c2
->cie_inf
->u
.cie
.u
.sec
->output_section
)
236 && c1
->per_encoding
== c2
->per_encoding
237 && c1
->lsda_encoding
== c2
->lsda_encoding
238 && c1
->fde_encoding
== c2
->fde_encoding
239 && c1
->initial_insn_length
== c2
->initial_insn_length
240 && c1
->initial_insn_length
<= sizeof (c1
->initial_instructions
)
241 && memcmp (c1
->initial_instructions
,
242 c2
->initial_instructions
,
243 c1
->initial_insn_length
) == 0)
250 cie_hash (const void *e
)
252 const struct cie
*c
= (const struct cie
*) e
;
257 cie_compute_hash (struct cie
*c
)
261 h
= iterative_hash_object (c
->length
, h
);
262 h
= iterative_hash_object (c
->version
, h
);
263 h
= iterative_hash (c
->augmentation
, strlen (c
->augmentation
) + 1, h
);
264 h
= iterative_hash_object (c
->code_align
, h
);
265 h
= iterative_hash_object (c
->data_align
, h
);
266 h
= iterative_hash_object (c
->ra_column
, h
);
267 h
= iterative_hash_object (c
->augmentation_size
, h
);
268 h
= iterative_hash_object (c
->personality
, h
);
269 h
= iterative_hash_object (c
->cie_inf
->u
.cie
.u
.sec
->output_section
, h
);
270 h
= iterative_hash_object (c
->per_encoding
, h
);
271 h
= iterative_hash_object (c
->lsda_encoding
, h
);
272 h
= iterative_hash_object (c
->fde_encoding
, h
);
273 h
= iterative_hash_object (c
->initial_insn_length
, h
);
274 len
= c
->initial_insn_length
;
275 if (len
> sizeof (c
->initial_instructions
))
276 len
= sizeof (c
->initial_instructions
);
277 h
= iterative_hash (c
->initial_instructions
, len
, h
);
282 /* Return the number of extra bytes that we'll be inserting into
283 ENTRY's augmentation string. */
285 static INLINE
unsigned int
286 extra_augmentation_string_bytes (struct eh_cie_fde
*entry
)
288 unsigned int size
= 0;
291 if (entry
->add_augmentation_size
)
293 if (entry
->u
.cie
.add_fde_encoding
)
299 /* Likewise ENTRY's augmentation data. */
301 static INLINE
unsigned int
302 extra_augmentation_data_bytes (struct eh_cie_fde
*entry
)
304 unsigned int size
= 0;
305 if (entry
->add_augmentation_size
)
307 if (entry
->cie
&& entry
->u
.cie
.add_fde_encoding
)
312 /* Return the size that ENTRY will have in the output. ALIGNMENT is the
313 required alignment of ENTRY in bytes. */
316 size_of_output_cie_fde (struct eh_cie_fde
*entry
, unsigned int alignment
)
320 if (entry
->size
== 4)
323 + extra_augmentation_string_bytes (entry
)
324 + extra_augmentation_data_bytes (entry
)
325 + alignment
- 1) & -alignment
;
328 /* Assume that the bytes between *ITER and END are CFA instructions.
329 Try to move *ITER past the first instruction and return true on
330 success. ENCODED_PTR_WIDTH gives the width of pointer entries. */
333 skip_cfa_op (bfd_byte
**iter
, bfd_byte
*end
, unsigned int encoded_ptr_width
)
338 if (!read_byte (iter
, end
, &op
))
341 switch (op
& 0xc0 ? op
& 0xc0 : op
)
344 case DW_CFA_advance_loc
:
346 case DW_CFA_remember_state
:
347 case DW_CFA_restore_state
:
348 case DW_CFA_GNU_window_save
:
353 case DW_CFA_restore_extended
:
354 case DW_CFA_undefined
:
355 case DW_CFA_same_value
:
356 case DW_CFA_def_cfa_register
:
357 case DW_CFA_def_cfa_offset
:
358 case DW_CFA_def_cfa_offset_sf
:
359 case DW_CFA_GNU_args_size
:
360 /* One leb128 argument. */
361 return skip_leb128 (iter
, end
);
363 case DW_CFA_val_offset
:
364 case DW_CFA_val_offset_sf
:
365 case DW_CFA_offset_extended
:
366 case DW_CFA_register
:
368 case DW_CFA_offset_extended_sf
:
369 case DW_CFA_GNU_negative_offset_extended
:
370 case DW_CFA_def_cfa_sf
:
371 /* Two leb128 arguments. */
372 return (skip_leb128 (iter
, end
)
373 && skip_leb128 (iter
, end
));
375 case DW_CFA_def_cfa_expression
:
376 /* A variable-length argument. */
377 return (read_uleb128 (iter
, end
, &length
)
378 && skip_bytes (iter
, end
, length
));
380 case DW_CFA_expression
:
381 case DW_CFA_val_expression
:
382 /* A leb128 followed by a variable-length argument. */
383 return (skip_leb128 (iter
, end
)
384 && read_uleb128 (iter
, end
, &length
)
385 && skip_bytes (iter
, end
, length
));
388 return skip_bytes (iter
, end
, encoded_ptr_width
);
390 case DW_CFA_advance_loc1
:
391 return skip_bytes (iter
, end
, 1);
393 case DW_CFA_advance_loc2
:
394 return skip_bytes (iter
, end
, 2);
396 case DW_CFA_advance_loc4
:
397 return skip_bytes (iter
, end
, 4);
399 case DW_CFA_MIPS_advance_loc8
:
400 return skip_bytes (iter
, end
, 8);
407 /* Try to interpret the bytes between BUF and END as CFA instructions.
408 If every byte makes sense, return a pointer to the first DW_CFA_nop
409 padding byte, or END if there is no padding. Return null otherwise.
410 ENCODED_PTR_WIDTH is as for skip_cfa_op. */
413 skip_non_nops (bfd_byte
*buf
, bfd_byte
*end
, unsigned int encoded_ptr_width
,
414 unsigned int *set_loc_count
)
420 if (*buf
== DW_CFA_nop
)
424 if (*buf
== DW_CFA_set_loc
)
426 if (!skip_cfa_op (&buf
, end
, encoded_ptr_width
))
433 /* Convert absolute encoding ENCODING into PC-relative form.
434 SIZE is the size of a pointer. */
437 make_pc_relative (unsigned char encoding
, unsigned int ptr_size
)
439 if ((encoding
& 0x7f) == DW_EH_PE_absptr
)
443 encoding
|= DW_EH_PE_sdata2
;
446 encoding
|= DW_EH_PE_sdata4
;
449 encoding
|= DW_EH_PE_sdata8
;
452 return encoding
| DW_EH_PE_pcrel
;
455 /* Try to parse .eh_frame section SEC, which belongs to ABFD. Store the
456 information in the section's sec_info field on success. COOKIE
457 describes the relocations in SEC. */
460 _bfd_elf_parse_eh_frame (bfd
*abfd
, struct bfd_link_info
*info
,
461 asection
*sec
, struct elf_reloc_cookie
*cookie
)
463 #define REQUIRE(COND) \
466 goto free_no_table; \
469 bfd_byte
*ehbuf
= NULL
, *buf
, *end
;
471 struct eh_cie_fde
*this_inf
;
472 unsigned int hdr_length
, hdr_id
;
473 unsigned int cie_count
;
474 struct cie
*cie
, *local_cies
= NULL
;
475 struct elf_link_hash_table
*htab
;
476 struct eh_frame_hdr_info
*hdr_info
;
477 struct eh_frame_sec_info
*sec_info
= NULL
;
478 unsigned int ptr_size
;
479 unsigned int num_cies
;
480 unsigned int num_entries
;
481 elf_gc_mark_hook_fn gc_mark_hook
;
483 htab
= elf_hash_table (info
);
484 hdr_info
= &htab
->eh_info
;
487 || sec
->sec_info_type
!= SEC_INFO_TYPE_NONE
)
489 /* This file does not contain .eh_frame information. */
493 if (bfd_is_abs_section (sec
->output_section
))
495 /* At least one of the sections is being discarded from the
496 link, so we should just ignore them. */
500 /* Read the frame unwind information from abfd. */
502 REQUIRE (bfd_malloc_and_get_section (abfd
, sec
, &ehbuf
));
505 && bfd_get_32 (abfd
, ehbuf
) == 0
506 && cookie
->rel
== cookie
->relend
)
508 /* Empty .eh_frame section. */
513 /* If .eh_frame section size doesn't fit into int, we cannot handle
514 it (it would need to use 64-bit .eh_frame format anyway). */
515 REQUIRE (sec
->size
== (unsigned int) sec
->size
);
517 ptr_size
= (get_elf_backend_data (abfd
)
518 ->elf_backend_eh_frame_address_size (abfd
, sec
));
519 REQUIRE (ptr_size
!= 0);
521 /* Go through the section contents and work out how many FDEs and
524 end
= ehbuf
+ sec
->size
;
531 /* Read the length of the entry. */
532 REQUIRE (skip_bytes (&buf
, end
, 4));
533 hdr_length
= bfd_get_32 (abfd
, buf
- 4);
535 /* 64-bit .eh_frame is not supported. */
536 REQUIRE (hdr_length
!= 0xffffffff);
540 REQUIRE (skip_bytes (&buf
, end
, 4));
541 hdr_id
= bfd_get_32 (abfd
, buf
- 4);
545 REQUIRE (skip_bytes (&buf
, end
, hdr_length
- 4));
548 sec_info
= (struct eh_frame_sec_info
*)
549 bfd_zmalloc (sizeof (struct eh_frame_sec_info
)
550 + (num_entries
- 1) * sizeof (struct eh_cie_fde
));
553 /* We need to have a "struct cie" for each CIE in this section. */
554 local_cies
= (struct cie
*) bfd_zmalloc (num_cies
* sizeof (*local_cies
));
555 REQUIRE (local_cies
);
557 /* FIXME: octets_per_byte. */
558 #define ENSURE_NO_RELOCS(buf) \
559 REQUIRE (!(cookie->rel < cookie->relend \
560 && (cookie->rel->r_offset \
561 < (bfd_size_type) ((buf) - ehbuf)) \
562 && cookie->rel->r_info != 0))
564 /* FIXME: octets_per_byte. */
565 #define SKIP_RELOCS(buf) \
566 while (cookie->rel < cookie->relend \
567 && (cookie->rel->r_offset \
568 < (bfd_size_type) ((buf) - ehbuf))) \
571 /* FIXME: octets_per_byte. */
572 #define GET_RELOC(buf) \
573 ((cookie->rel < cookie->relend \
574 && (cookie->rel->r_offset \
575 == (bfd_size_type) ((buf) - ehbuf))) \
576 ? cookie->rel : NULL)
580 gc_mark_hook
= get_elf_backend_data (abfd
)->gc_mark_hook
;
581 while ((bfd_size_type
) (buf
- ehbuf
) != sec
->size
)
584 bfd_byte
*start
, *insns
, *insns_end
;
585 bfd_size_type length
;
586 unsigned int set_loc_count
;
588 this_inf
= sec_info
->entry
+ sec_info
->count
;
591 /* Read the length of the entry. */
592 REQUIRE (skip_bytes (&buf
, ehbuf
+ sec
->size
, 4));
593 hdr_length
= bfd_get_32 (abfd
, buf
- 4);
595 /* The CIE/FDE must be fully contained in this input section. */
596 REQUIRE ((bfd_size_type
) (buf
- ehbuf
) + hdr_length
<= sec
->size
);
597 end
= buf
+ hdr_length
;
599 this_inf
->offset
= last_fde
- ehbuf
;
600 this_inf
->size
= 4 + hdr_length
;
601 this_inf
->reloc_index
= cookie
->rel
- cookie
->rels
;
605 /* A zero-length CIE should only be found at the end of
607 REQUIRE ((bfd_size_type
) (buf
- ehbuf
) == sec
->size
);
608 ENSURE_NO_RELOCS (buf
);
613 REQUIRE (skip_bytes (&buf
, end
, 4));
614 hdr_id
= bfd_get_32 (abfd
, buf
- 4);
618 unsigned int initial_insn_length
;
623 /* Point CIE to one of the section-local cie structures. */
624 cie
= local_cies
+ cie_count
++;
626 cie
->cie_inf
= this_inf
;
627 cie
->length
= hdr_length
;
629 REQUIRE (read_byte (&buf
, end
, &cie
->version
));
631 /* Cannot handle unknown versions. */
632 REQUIRE (cie
->version
== 1
634 || cie
->version
== 4);
635 REQUIRE (strlen ((char *) buf
) < sizeof (cie
->augmentation
));
637 strcpy (cie
->augmentation
, (char *) buf
);
638 buf
= (bfd_byte
*) strchr ((char *) buf
, '\0') + 1;
639 ENSURE_NO_RELOCS (buf
);
640 if (buf
[0] == 'e' && buf
[1] == 'h')
642 /* GCC < 3.0 .eh_frame CIE */
643 /* We cannot merge "eh" CIEs because __EXCEPTION_TABLE__
644 is private to each CIE, so we don't need it for anything.
646 REQUIRE (skip_bytes (&buf
, end
, ptr_size
));
649 if (cie
->version
>= 4)
651 REQUIRE (buf
+ 1 < end
);
652 REQUIRE (buf
[0] == ptr_size
);
653 REQUIRE (buf
[1] == 0);
656 REQUIRE (read_uleb128 (&buf
, end
, &cie
->code_align
));
657 REQUIRE (read_sleb128 (&buf
, end
, &cie
->data_align
));
658 if (cie
->version
== 1)
661 cie
->ra_column
= *buf
++;
664 REQUIRE (read_uleb128 (&buf
, end
, &cie
->ra_column
));
665 ENSURE_NO_RELOCS (buf
);
666 cie
->lsda_encoding
= DW_EH_PE_omit
;
667 cie
->fde_encoding
= DW_EH_PE_omit
;
668 cie
->per_encoding
= DW_EH_PE_omit
;
669 aug
= cie
->augmentation
;
670 if (aug
[0] != 'e' || aug
[1] != 'h')
675 REQUIRE (read_uleb128 (&buf
, end
, &cie
->augmentation_size
));
676 ENSURE_NO_RELOCS (buf
);
683 REQUIRE (read_byte (&buf
, end
, &cie
->lsda_encoding
));
684 ENSURE_NO_RELOCS (buf
);
685 REQUIRE (get_DW_EH_PE_width (cie
->lsda_encoding
, ptr_size
));
688 REQUIRE (read_byte (&buf
, end
, &cie
->fde_encoding
));
689 ENSURE_NO_RELOCS (buf
);
690 REQUIRE (get_DW_EH_PE_width (cie
->fde_encoding
, ptr_size
));
698 REQUIRE (read_byte (&buf
, end
, &cie
->per_encoding
));
699 per_width
= get_DW_EH_PE_width (cie
->per_encoding
,
702 if ((cie
->per_encoding
& 0x70) == DW_EH_PE_aligned
)
704 length
= -(buf
- ehbuf
) & (per_width
- 1);
705 REQUIRE (skip_bytes (&buf
, end
, length
));
707 this_inf
->u
.cie
.personality_offset
= buf
- start
;
708 ENSURE_NO_RELOCS (buf
);
709 /* Ensure we have a reloc here. */
710 REQUIRE (GET_RELOC (buf
));
711 cie
->personality
.reloc_index
712 = cookie
->rel
- cookie
->rels
;
713 /* Cope with MIPS-style composite relocations. */
716 while (GET_RELOC (buf
) != NULL
);
717 REQUIRE (skip_bytes (&buf
, end
, per_width
));
721 /* Unrecognized augmentation. Better bail out. */
726 /* For shared libraries, try to get rid of as many RELATIVE relocs
729 && (get_elf_backend_data (abfd
)
730 ->elf_backend_can_make_relative_eh_frame
733 if ((cie
->fde_encoding
& 0x70) == DW_EH_PE_absptr
)
734 this_inf
->make_relative
= 1;
735 /* If the CIE doesn't already have an 'R' entry, it's fairly
736 easy to add one, provided that there's no aligned data
737 after the augmentation string. */
738 else if (cie
->fde_encoding
== DW_EH_PE_omit
739 && (cie
->per_encoding
& 0x70) != DW_EH_PE_aligned
)
741 if (*cie
->augmentation
== 0)
742 this_inf
->add_augmentation_size
= 1;
743 this_inf
->u
.cie
.add_fde_encoding
= 1;
744 this_inf
->make_relative
= 1;
747 if ((cie
->lsda_encoding
& 0x70) == DW_EH_PE_absptr
)
748 cie
->can_make_lsda_relative
= 1;
751 /* If FDE encoding was not specified, it defaults to
753 if (cie
->fde_encoding
== DW_EH_PE_omit
)
754 cie
->fde_encoding
= DW_EH_PE_absptr
;
756 initial_insn_length
= end
- buf
;
757 cie
->initial_insn_length
= initial_insn_length
;
758 memcpy (cie
->initial_instructions
, buf
,
759 initial_insn_length
<= sizeof (cie
->initial_instructions
)
760 ? initial_insn_length
: sizeof (cie
->initial_instructions
));
762 buf
+= initial_insn_length
;
763 ENSURE_NO_RELOCS (buf
);
765 if (!info
->relocatable
)
766 /* Keep info for merging cies. */
767 this_inf
->u
.cie
.u
.full_cie
= cie
;
768 this_inf
->u
.cie
.per_encoding_relative
769 = (cie
->per_encoding
& 0x70) == DW_EH_PE_pcrel
;
773 /* Find the corresponding CIE. */
774 unsigned int cie_offset
= this_inf
->offset
+ 4 - hdr_id
;
775 for (cie
= local_cies
; cie
< local_cies
+ cie_count
; cie
++)
776 if (cie_offset
== cie
->cie_inf
->offset
)
779 /* Ensure this FDE references one of the CIEs in this input
781 REQUIRE (cie
!= local_cies
+ cie_count
);
782 this_inf
->u
.fde
.cie_inf
= cie
->cie_inf
;
783 this_inf
->make_relative
= cie
->cie_inf
->make_relative
;
784 this_inf
->add_augmentation_size
785 = cie
->cie_inf
->add_augmentation_size
;
787 ENSURE_NO_RELOCS (buf
);
788 if ((sec
->flags
& SEC_LINKER_CREATED
) == 0 || cookie
->rels
!= NULL
)
792 REQUIRE (GET_RELOC (buf
));
794 /* Chain together the FDEs for each section. */
795 rsec
= _bfd_elf_gc_mark_rsec (info
, sec
, gc_mark_hook
, cookie
);
796 /* RSEC will be NULL if FDE was cleared out as it was belonging to
797 a discarded SHT_GROUP. */
800 REQUIRE (rsec
->owner
== abfd
);
801 this_inf
->u
.fde
.next_for_section
= elf_fde_list (rsec
);
802 elf_fde_list (rsec
) = this_inf
;
806 /* Skip the initial location and address range. */
808 length
= get_DW_EH_PE_width (cie
->fde_encoding
, ptr_size
);
809 REQUIRE (skip_bytes (&buf
, end
, 2 * length
));
811 /* Skip the augmentation size, if present. */
812 if (cie
->augmentation
[0] == 'z')
813 REQUIRE (read_uleb128 (&buf
, end
, &length
));
817 /* Of the supported augmentation characters above, only 'L'
818 adds augmentation data to the FDE. This code would need to
819 be adjusted if any future augmentations do the same thing. */
820 if (cie
->lsda_encoding
!= DW_EH_PE_omit
)
823 if (cie
->can_make_lsda_relative
&& GET_RELOC (buf
))
824 cie
->cie_inf
->u
.cie
.make_lsda_relative
= 1;
825 this_inf
->lsda_offset
= buf
- start
;
826 /* If there's no 'z' augmentation, we don't know where the
827 CFA insns begin. Assume no padding. */
828 if (cie
->augmentation
[0] != 'z')
832 /* Skip over the augmentation data. */
833 REQUIRE (skip_bytes (&buf
, end
, length
));
836 buf
= last_fde
+ 4 + hdr_length
;
838 /* For NULL RSEC (cleared FDE belonging to a discarded section)
839 the relocations are commonly cleared. We do not sanity check if
840 all these relocations are cleared as (1) relocations to
841 .gcc_except_table will remain uncleared (they will get dropped
842 with the drop of this unused FDE) and (2) BFD already safely drops
843 relocations of any type to .eh_frame by
844 elf_section_ignore_discarded_relocs.
845 TODO: The .gcc_except_table entries should be also filtered as
846 .eh_frame entries; or GCC could rather use COMDAT for them. */
850 /* Try to interpret the CFA instructions and find the first
851 padding nop. Shrink this_inf's size so that it doesn't
852 include the padding. */
853 length
= get_DW_EH_PE_width (cie
->fde_encoding
, ptr_size
);
855 insns_end
= skip_non_nops (insns
, end
, length
, &set_loc_count
);
856 /* If we don't understand the CFA instructions, we can't know
857 what needs to be adjusted there. */
858 if (insns_end
== NULL
859 /* For the time being we don't support DW_CFA_set_loc in
861 || (set_loc_count
&& this_inf
->cie
))
863 this_inf
->size
-= end
- insns_end
;
864 if (insns_end
!= end
&& this_inf
->cie
)
866 cie
->initial_insn_length
-= end
- insns_end
;
867 cie
->length
-= end
- insns_end
;
870 && ((cie
->fde_encoding
& 0x70) == DW_EH_PE_pcrel
871 || this_inf
->make_relative
))
876 this_inf
->set_loc
= (unsigned int *)
877 bfd_malloc ((set_loc_count
+ 1) * sizeof (unsigned int));
878 REQUIRE (this_inf
->set_loc
);
879 this_inf
->set_loc
[0] = set_loc_count
;
884 if (*p
== DW_CFA_set_loc
)
885 this_inf
->set_loc
[++cnt
] = p
+ 1 - start
;
886 REQUIRE (skip_cfa_op (&p
, end
, length
));
890 this_inf
->removed
= 1;
891 this_inf
->fde_encoding
= cie
->fde_encoding
;
892 this_inf
->lsda_encoding
= cie
->lsda_encoding
;
895 BFD_ASSERT (sec_info
->count
== num_entries
);
896 BFD_ASSERT (cie_count
== num_cies
);
898 elf_section_data (sec
)->sec_info
= sec_info
;
899 sec
->sec_info_type
= SEC_INFO_TYPE_EH_FRAME
;
900 if (!info
->relocatable
)
902 /* Keep info for merging cies. */
903 sec_info
->cies
= local_cies
;
909 (*info
->callbacks
->einfo
)
910 (_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"),
912 hdr_info
->table
= FALSE
;
923 /* Mark all relocations against CIE or FDE ENT, which occurs in
924 .eh_frame section SEC. COOKIE describes the relocations in SEC;
925 its "rel" field can be changed freely. */
928 mark_entry (struct bfd_link_info
*info
, asection
*sec
,
929 struct eh_cie_fde
*ent
, elf_gc_mark_hook_fn gc_mark_hook
,
930 struct elf_reloc_cookie
*cookie
)
932 /* FIXME: octets_per_byte. */
933 for (cookie
->rel
= cookie
->rels
+ ent
->reloc_index
;
934 cookie
->rel
< cookie
->relend
935 && cookie
->rel
->r_offset
< ent
->offset
+ ent
->size
;
937 if (!_bfd_elf_gc_mark_reloc (info
, sec
, gc_mark_hook
, cookie
))
943 /* Mark all the relocations against FDEs that relate to code in input
944 section SEC. The FDEs belong to .eh_frame section EH_FRAME, whose
945 relocations are described by COOKIE. */
948 _bfd_elf_gc_mark_fdes (struct bfd_link_info
*info
, asection
*sec
,
949 asection
*eh_frame
, elf_gc_mark_hook_fn gc_mark_hook
,
950 struct elf_reloc_cookie
*cookie
)
952 struct eh_cie_fde
*fde
, *cie
;
954 for (fde
= elf_fde_list (sec
); fde
; fde
= fde
->u
.fde
.next_for_section
)
956 if (!mark_entry (info
, eh_frame
, fde
, gc_mark_hook
, cookie
))
959 /* At this stage, all cie_inf fields point to local CIEs, so we
960 can use the same cookie to refer to them. */
961 cie
= fde
->u
.fde
.cie_inf
;
962 if (!cie
->u
.cie
.gc_mark
)
964 cie
->u
.cie
.gc_mark
= 1;
965 if (!mark_entry (info
, eh_frame
, cie
, gc_mark_hook
, cookie
))
972 /* Input section SEC of ABFD is an .eh_frame section that contains the
973 CIE described by CIE_INF. Return a version of CIE_INF that is going
974 to be kept in the output, adding CIE_INF to the output if necessary.
976 HDR_INFO is the .eh_frame_hdr information and COOKIE describes the
977 relocations in REL. */
979 static struct eh_cie_fde
*
980 find_merged_cie (bfd
*abfd
, struct bfd_link_info
*info
, asection
*sec
,
981 struct eh_frame_hdr_info
*hdr_info
,
982 struct elf_reloc_cookie
*cookie
,
983 struct eh_cie_fde
*cie_inf
)
985 unsigned long r_symndx
;
986 struct cie
*cie
, *new_cie
;
987 Elf_Internal_Rela
*rel
;
990 /* Use CIE_INF if we have already decided to keep it. */
991 if (!cie_inf
->removed
)
994 /* If we have merged CIE_INF with another CIE, use that CIE instead. */
995 if (cie_inf
->u
.cie
.merged
)
996 return cie_inf
->u
.cie
.u
.merged_with
;
998 cie
= cie_inf
->u
.cie
.u
.full_cie
;
1000 /* Assume we will need to keep CIE_INF. */
1001 cie_inf
->removed
= 0;
1002 cie_inf
->u
.cie
.u
.sec
= sec
;
1004 /* If we are not merging CIEs, use CIE_INF. */
1008 if (cie
->per_encoding
!= DW_EH_PE_omit
)
1010 bfd_boolean per_binds_local
;
1012 /* Work out the address of personality routine, or at least
1013 enough info that we could calculate the address had we made a
1014 final section layout. The symbol on the reloc is enough,
1015 either the hash for a global, or (bfd id, index) pair for a
1016 local. The assumption here is that no one uses addends on
1018 rel
= cookie
->rels
+ cie
->personality
.reloc_index
;
1019 memset (&cie
->personality
, 0, sizeof (cie
->personality
));
1021 if (elf_elfheader (abfd
)->e_ident
[EI_CLASS
] == ELFCLASS64
)
1022 r_symndx
= ELF64_R_SYM (rel
->r_info
);
1025 r_symndx
= ELF32_R_SYM (rel
->r_info
);
1026 if (r_symndx
>= cookie
->locsymcount
1027 || ELF_ST_BIND (cookie
->locsyms
[r_symndx
].st_info
) != STB_LOCAL
)
1029 struct elf_link_hash_entry
*h
;
1031 r_symndx
-= cookie
->extsymoff
;
1032 h
= cookie
->sym_hashes
[r_symndx
];
1034 while (h
->root
.type
== bfd_link_hash_indirect
1035 || h
->root
.type
== bfd_link_hash_warning
)
1036 h
= (struct elf_link_hash_entry
*) h
->root
.u
.i
.link
;
1038 cie
->personality
.h
= h
;
1039 per_binds_local
= SYMBOL_REFERENCES_LOCAL (info
, h
);
1043 Elf_Internal_Sym
*sym
;
1046 sym
= &cookie
->locsyms
[r_symndx
];
1047 sym_sec
= bfd_section_from_elf_index (abfd
, sym
->st_shndx
);
1048 if (sym_sec
== NULL
)
1051 if (sym_sec
->kept_section
!= NULL
)
1052 sym_sec
= sym_sec
->kept_section
;
1053 if (sym_sec
->output_section
== NULL
)
1056 cie
->local_personality
= 1;
1057 cie
->personality
.sym
.bfd_id
= abfd
->id
;
1058 cie
->personality
.sym
.index
= r_symndx
;
1059 per_binds_local
= TRUE
;
1064 && (cie
->per_encoding
& 0x70) == DW_EH_PE_absptr
1065 && (get_elf_backend_data (abfd
)
1066 ->elf_backend_can_make_relative_eh_frame (abfd
, info
, sec
)))
1068 cie_inf
->u
.cie
.make_per_encoding_relative
= 1;
1069 cie_inf
->u
.cie
.per_encoding_relative
= 1;
1073 /* See if we can merge this CIE with an earlier one. */
1074 cie_compute_hash (cie
);
1075 if (hdr_info
->cies
== NULL
)
1077 hdr_info
->cies
= htab_try_create (1, cie_hash
, cie_eq
, free
);
1078 if (hdr_info
->cies
== NULL
)
1081 loc
= htab_find_slot_with_hash (hdr_info
->cies
, cie
, cie
->hash
, INSERT
);
1085 new_cie
= (struct cie
*) *loc
;
1086 if (new_cie
== NULL
)
1088 /* Keep CIE_INF and record it in the hash table. */
1089 new_cie
= (struct cie
*) malloc (sizeof (struct cie
));
1090 if (new_cie
== NULL
)
1093 memcpy (new_cie
, cie
, sizeof (struct cie
));
1098 /* Merge CIE_INF with NEW_CIE->CIE_INF. */
1099 cie_inf
->removed
= 1;
1100 cie_inf
->u
.cie
.merged
= 1;
1101 cie_inf
->u
.cie
.u
.merged_with
= new_cie
->cie_inf
;
1102 if (cie_inf
->u
.cie
.make_lsda_relative
)
1103 new_cie
->cie_inf
->u
.cie
.make_lsda_relative
= 1;
1105 return new_cie
->cie_inf
;
1108 /* This function is called for each input file before the .eh_frame
1109 section is relocated. It discards duplicate CIEs and FDEs for discarded
1110 functions. The function returns TRUE iff any entries have been
1114 _bfd_elf_discard_section_eh_frame
1115 (bfd
*abfd
, struct bfd_link_info
*info
, asection
*sec
,
1116 bfd_boolean (*reloc_symbol_deleted_p
) (bfd_vma
, void *),
1117 struct elf_reloc_cookie
*cookie
)
1119 struct eh_cie_fde
*ent
;
1120 struct eh_frame_sec_info
*sec_info
;
1121 struct eh_frame_hdr_info
*hdr_info
;
1122 unsigned int ptr_size
, offset
;
1124 if (sec
->sec_info_type
!= SEC_INFO_TYPE_EH_FRAME
)
1127 sec_info
= (struct eh_frame_sec_info
*) elf_section_data (sec
)->sec_info
;
1128 if (sec_info
== NULL
)
1131 ptr_size
= (get_elf_backend_data (sec
->owner
)
1132 ->elf_backend_eh_frame_address_size (sec
->owner
, sec
));
1134 hdr_info
= &elf_hash_table (info
)->eh_info
;
1135 for (ent
= sec_info
->entry
; ent
< sec_info
->entry
+ sec_info
->count
; ++ent
)
1137 /* There should only be one zero terminator, on the last input
1138 file supplying .eh_frame (crtend.o). Remove any others. */
1139 ent
->removed
= sec
->map_head
.s
!= NULL
;
1143 if ((sec
->flags
& SEC_LINKER_CREATED
) != 0 && cookie
->rels
== NULL
)
1146 = get_DW_EH_PE_width (ent
->fde_encoding
, ptr_size
);
1148 = read_value (abfd
, sec
->contents
+ ent
->offset
+ 8 + width
,
1149 width
, get_DW_EH_PE_signed (ent
->fde_encoding
));
1154 cookie
->rel
= cookie
->rels
+ ent
->reloc_index
;
1155 /* FIXME: octets_per_byte. */
1156 BFD_ASSERT (cookie
->rel
< cookie
->relend
1157 && cookie
->rel
->r_offset
== ent
->offset
+ 8);
1158 keep
= !(*reloc_symbol_deleted_p
) (ent
->offset
+ 8, cookie
);
1163 && (((ent
->fde_encoding
& 0x70) == DW_EH_PE_absptr
1164 && ent
->make_relative
== 0)
1165 || (ent
->fde_encoding
& 0x70) == DW_EH_PE_aligned
))
1167 /* If a shared library uses absolute pointers
1168 which we cannot turn into PC relative,
1169 don't create the binary search table,
1170 since it is affected by runtime relocations. */
1171 hdr_info
->table
= FALSE
;
1172 (*info
->callbacks
->einfo
)
1173 (_("%P: fde encoding in %B(%A) prevents .eh_frame_hdr"
1174 " table being created.\n"), abfd
, sec
);
1177 hdr_info
->fde_count
++;
1178 ent
->u
.fde
.cie_inf
= find_merged_cie (abfd
, info
, sec
, hdr_info
,
1179 cookie
, ent
->u
.fde
.cie_inf
);
1185 free (sec_info
->cies
);
1186 sec_info
->cies
= NULL
;
1190 for (ent
= sec_info
->entry
; ent
< sec_info
->entry
+ sec_info
->count
; ++ent
)
1193 ent
->new_offset
= offset
;
1194 offset
+= size_of_output_cie_fde (ent
, ptr_size
);
1197 sec
->rawsize
= sec
->size
;
1199 return offset
!= sec
->rawsize
;
1202 /* This function is called for .eh_frame_hdr section after
1203 _bfd_elf_discard_section_eh_frame has been called on all .eh_frame
1204 input sections. It finalizes the size of .eh_frame_hdr section. */
1207 _bfd_elf_discard_section_eh_frame_hdr (bfd
*abfd
, struct bfd_link_info
*info
)
1209 struct elf_link_hash_table
*htab
;
1210 struct eh_frame_hdr_info
*hdr_info
;
1213 htab
= elf_hash_table (info
);
1214 hdr_info
= &htab
->eh_info
;
1216 if (hdr_info
->cies
!= NULL
)
1218 htab_delete (hdr_info
->cies
);
1219 hdr_info
->cies
= NULL
;
1222 sec
= hdr_info
->hdr_sec
;
1226 sec
->size
= EH_FRAME_HDR_SIZE
;
1227 if (hdr_info
->table
)
1228 sec
->size
+= 4 + hdr_info
->fde_count
* 8;
1230 elf_eh_frame_hdr (abfd
) = sec
;
1234 /* Return true if there is at least one non-empty .eh_frame section in
1235 input files. Can only be called after ld has mapped input to
1236 output sections, and before sections are stripped. */
1238 _bfd_elf_eh_frame_present (struct bfd_link_info
*info
)
1240 asection
*eh
= bfd_get_section_by_name (info
->output_bfd
, ".eh_frame");
1245 /* Count only sections which have at least a single CIE or FDE.
1246 There cannot be any CIE or FDE <= 8 bytes. */
1247 for (eh
= eh
->map_head
.s
; eh
!= NULL
; eh
= eh
->map_head
.s
)
1254 /* This function is called from size_dynamic_sections.
1255 It needs to decide whether .eh_frame_hdr should be output or not,
1256 because when the dynamic symbol table has been sized it is too late
1257 to strip sections. */
1260 _bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info
*info
)
1262 struct elf_link_hash_table
*htab
;
1263 struct eh_frame_hdr_info
*hdr_info
;
1265 htab
= elf_hash_table (info
);
1266 hdr_info
= &htab
->eh_info
;
1267 if (hdr_info
->hdr_sec
== NULL
)
1270 if (bfd_is_abs_section (hdr_info
->hdr_sec
->output_section
)
1271 || !info
->eh_frame_hdr
1272 || !_bfd_elf_eh_frame_present (info
))
1274 hdr_info
->hdr_sec
->flags
|= SEC_EXCLUDE
;
1275 hdr_info
->hdr_sec
= NULL
;
1279 hdr_info
->table
= TRUE
;
1283 /* Adjust an address in the .eh_frame section. Given OFFSET within
1284 SEC, this returns the new offset in the adjusted .eh_frame section,
1285 or -1 if the address refers to a CIE/FDE which has been removed
1286 or to offset with dynamic relocation which is no longer needed. */
1289 _bfd_elf_eh_frame_section_offset (bfd
*output_bfd ATTRIBUTE_UNUSED
,
1290 struct bfd_link_info
*info ATTRIBUTE_UNUSED
,
1294 struct eh_frame_sec_info
*sec_info
;
1295 unsigned int lo
, hi
, mid
;
1297 if (sec
->sec_info_type
!= SEC_INFO_TYPE_EH_FRAME
)
1299 sec_info
= (struct eh_frame_sec_info
*) elf_section_data (sec
)->sec_info
;
1301 if (offset
>= sec
->rawsize
)
1302 return offset
- sec
->rawsize
+ sec
->size
;
1305 hi
= sec_info
->count
;
1309 mid
= (lo
+ hi
) / 2;
1310 if (offset
< sec_info
->entry
[mid
].offset
)
1313 >= sec_info
->entry
[mid
].offset
+ sec_info
->entry
[mid
].size
)
1319 BFD_ASSERT (lo
< hi
);
1321 /* FDE or CIE was removed. */
1322 if (sec_info
->entry
[mid
].removed
)
1323 return (bfd_vma
) -1;
1325 /* If converting personality pointers to DW_EH_PE_pcrel, there will be
1326 no need for run-time relocation against the personality field. */
1327 if (sec_info
->entry
[mid
].cie
1328 && sec_info
->entry
[mid
].u
.cie
.make_per_encoding_relative
1329 && offset
== (sec_info
->entry
[mid
].offset
+ 8
1330 + sec_info
->entry
[mid
].u
.cie
.personality_offset
))
1331 return (bfd_vma
) -2;
1333 /* If converting to DW_EH_PE_pcrel, there will be no need for run-time
1334 relocation against FDE's initial_location field. */
1335 if (!sec_info
->entry
[mid
].cie
1336 && sec_info
->entry
[mid
].make_relative
1337 && offset
== sec_info
->entry
[mid
].offset
+ 8)
1338 return (bfd_vma
) -2;
1340 /* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need
1341 for run-time relocation against LSDA field. */
1342 if (!sec_info
->entry
[mid
].cie
1343 && sec_info
->entry
[mid
].u
.fde
.cie_inf
->u
.cie
.make_lsda_relative
1344 && offset
== (sec_info
->entry
[mid
].offset
+ 8
1345 + sec_info
->entry
[mid
].lsda_offset
))
1346 return (bfd_vma
) -2;
1348 /* If converting to DW_EH_PE_pcrel, there will be no need for run-time
1349 relocation against DW_CFA_set_loc's arguments. */
1350 if (sec_info
->entry
[mid
].set_loc
1351 && sec_info
->entry
[mid
].make_relative
1352 && (offset
>= sec_info
->entry
[mid
].offset
+ 8
1353 + sec_info
->entry
[mid
].set_loc
[1]))
1357 for (cnt
= 1; cnt
<= sec_info
->entry
[mid
].set_loc
[0]; cnt
++)
1358 if (offset
== sec_info
->entry
[mid
].offset
+ 8
1359 + sec_info
->entry
[mid
].set_loc
[cnt
])
1360 return (bfd_vma
) -2;
1363 /* Any new augmentation bytes go before the first relocation. */
1364 return (offset
+ sec_info
->entry
[mid
].new_offset
1365 - sec_info
->entry
[mid
].offset
1366 + extra_augmentation_string_bytes (sec_info
->entry
+ mid
)
1367 + extra_augmentation_data_bytes (sec_info
->entry
+ mid
));
1370 /* Write out .eh_frame section. This is called with the relocated
1374 _bfd_elf_write_section_eh_frame (bfd
*abfd
,
1375 struct bfd_link_info
*info
,
1379 struct eh_frame_sec_info
*sec_info
;
1380 struct elf_link_hash_table
*htab
;
1381 struct eh_frame_hdr_info
*hdr_info
;
1382 unsigned int ptr_size
;
1383 struct eh_cie_fde
*ent
;
1385 if (sec
->sec_info_type
!= SEC_INFO_TYPE_EH_FRAME
)
1386 /* FIXME: octets_per_byte. */
1387 return bfd_set_section_contents (abfd
, sec
->output_section
, contents
,
1388 sec
->output_offset
, sec
->size
);
1390 ptr_size
= (get_elf_backend_data (abfd
)
1391 ->elf_backend_eh_frame_address_size (abfd
, sec
));
1392 BFD_ASSERT (ptr_size
!= 0);
1394 sec_info
= (struct eh_frame_sec_info
*) elf_section_data (sec
)->sec_info
;
1395 htab
= elf_hash_table (info
);
1396 hdr_info
= &htab
->eh_info
;
1398 if (hdr_info
->table
&& hdr_info
->array
== NULL
)
1399 hdr_info
->array
= (struct eh_frame_array_ent
*)
1400 bfd_malloc (hdr_info
->fde_count
* sizeof(*hdr_info
->array
));
1401 if (hdr_info
->array
== NULL
)
1404 /* The new offsets can be bigger or smaller than the original offsets.
1405 We therefore need to make two passes over the section: one backward
1406 pass to move entries up and one forward pass to move entries down.
1407 The two passes won't interfere with each other because entries are
1409 for (ent
= sec_info
->entry
+ sec_info
->count
; ent
-- != sec_info
->entry
;)
1410 if (!ent
->removed
&& ent
->new_offset
> ent
->offset
)
1411 memmove (contents
+ ent
->new_offset
, contents
+ ent
->offset
, ent
->size
);
1413 for (ent
= sec_info
->entry
; ent
< sec_info
->entry
+ sec_info
->count
; ++ent
)
1414 if (!ent
->removed
&& ent
->new_offset
< ent
->offset
)
1415 memmove (contents
+ ent
->new_offset
, contents
+ ent
->offset
, ent
->size
);
1417 for (ent
= sec_info
->entry
; ent
< sec_info
->entry
+ sec_info
->count
; ++ent
)
1419 unsigned char *buf
, *end
;
1420 unsigned int new_size
;
1427 /* Any terminating FDE must be at the end of the section. */
1428 BFD_ASSERT (ent
== sec_info
->entry
+ sec_info
->count
- 1);
1432 buf
= contents
+ ent
->new_offset
;
1433 end
= buf
+ ent
->size
;
1434 new_size
= size_of_output_cie_fde (ent
, ptr_size
);
1436 /* Update the size. It may be shrinked. */
1437 bfd_put_32 (abfd
, new_size
- 4, buf
);
1439 /* Filling the extra bytes with DW_CFA_nops. */
1440 if (new_size
!= ent
->size
)
1441 memset (end
, 0, new_size
- ent
->size
);
1446 if (ent
->make_relative
1447 || ent
->u
.cie
.make_lsda_relative
1448 || ent
->u
.cie
.per_encoding_relative
)
1451 unsigned int action
, extra_string
, extra_data
;
1452 unsigned int per_width
, per_encoding
;
1454 /* Need to find 'R' or 'L' augmentation's argument and modify
1455 DW_EH_PE_* value. */
1456 action
= ((ent
->make_relative
? 1 : 0)
1457 | (ent
->u
.cie
.make_lsda_relative
? 2 : 0)
1458 | (ent
->u
.cie
.per_encoding_relative
? 4 : 0));
1459 extra_string
= extra_augmentation_string_bytes (ent
);
1460 extra_data
= extra_augmentation_data_bytes (ent
);
1462 /* Skip length, id and version. */
1465 buf
+= strlen (aug
) + 1;
1466 skip_leb128 (&buf
, end
);
1467 skip_leb128 (&buf
, end
);
1468 skip_leb128 (&buf
, end
);
1471 /* The uleb128 will always be a single byte for the kind
1472 of augmentation strings that we're prepared to handle. */
1473 *buf
++ += extra_data
;
1477 /* Make room for the new augmentation string and data bytes. */
1478 memmove (buf
+ extra_string
+ extra_data
, buf
, end
- buf
);
1479 memmove (aug
+ extra_string
, aug
, buf
- (bfd_byte
*) aug
);
1480 buf
+= extra_string
;
1481 end
+= extra_string
+ extra_data
;
1483 if (ent
->add_augmentation_size
)
1486 *buf
++ = extra_data
- 1;
1488 if (ent
->u
.cie
.add_fde_encoding
)
1490 BFD_ASSERT (action
& 1);
1492 *buf
++ = make_pc_relative (DW_EH_PE_absptr
, ptr_size
);
1502 BFD_ASSERT (*buf
== ent
->lsda_encoding
);
1503 *buf
= make_pc_relative (*buf
, ptr_size
);
1509 if (ent
->u
.cie
.make_per_encoding_relative
)
1510 *buf
= make_pc_relative (*buf
, ptr_size
);
1511 per_encoding
= *buf
++;
1512 per_width
= get_DW_EH_PE_width (per_encoding
, ptr_size
);
1513 BFD_ASSERT (per_width
!= 0);
1514 BFD_ASSERT (((per_encoding
& 0x70) == DW_EH_PE_pcrel
)
1515 == ent
->u
.cie
.per_encoding_relative
);
1516 if ((per_encoding
& 0x70) == DW_EH_PE_aligned
)
1518 + ((buf
- contents
+ per_width
- 1)
1519 & ~((bfd_size_type
) per_width
- 1)));
1524 val
= read_value (abfd
, buf
, per_width
,
1525 get_DW_EH_PE_signed (per_encoding
));
1526 if (ent
->u
.cie
.make_per_encoding_relative
)
1527 val
-= (sec
->output_section
->vma
1528 + sec
->output_offset
1529 + (buf
- contents
));
1532 val
+= (bfd_vma
) ent
->offset
- ent
->new_offset
;
1533 val
-= extra_string
+ extra_data
;
1535 write_value (abfd
, buf
, val
, per_width
);
1543 BFD_ASSERT (*buf
== ent
->fde_encoding
);
1544 *buf
= make_pc_relative (*buf
, ptr_size
);
1559 bfd_vma value
, address
;
1562 struct eh_cie_fde
*cie
;
1565 cie
= ent
->u
.fde
.cie_inf
;
1567 value
= ((ent
->new_offset
+ sec
->output_offset
+ 4)
1568 - (cie
->new_offset
+ cie
->u
.cie
.u
.sec
->output_offset
));
1569 bfd_put_32 (abfd
, value
, buf
);
1571 width
= get_DW_EH_PE_width (ent
->fde_encoding
, ptr_size
);
1572 value
= read_value (abfd
, buf
, width
,
1573 get_DW_EH_PE_signed (ent
->fde_encoding
));
1577 switch (ent
->fde_encoding
& 0x70)
1579 case DW_EH_PE_textrel
:
1580 BFD_ASSERT (hdr_info
== NULL
);
1582 case DW_EH_PE_datarel
:
1584 switch (abfd
->arch_info
->arch
)
1587 BFD_ASSERT (elf_gp (abfd
) != 0);
1588 address
+= elf_gp (abfd
);
1591 (*info
->callbacks
->einfo
)
1592 (_("%P: DW_EH_PE_datarel unspecified"
1593 " for this architecture.\n"));
1597 BFD_ASSERT (htab
->hgot
!= NULL
1598 && ((htab
->hgot
->root
.type
1599 == bfd_link_hash_defined
)
1600 || (htab
->hgot
->root
.type
1601 == bfd_link_hash_defweak
)));
1603 += (htab
->hgot
->root
.u
.def
.value
1604 + htab
->hgot
->root
.u
.def
.section
->output_offset
1605 + (htab
->hgot
->root
.u
.def
.section
->output_section
1611 case DW_EH_PE_pcrel
:
1612 value
+= (bfd_vma
) ent
->offset
- ent
->new_offset
;
1613 address
+= (sec
->output_section
->vma
1614 + sec
->output_offset
1618 if (ent
->make_relative
)
1619 value
-= (sec
->output_section
->vma
1620 + sec
->output_offset
1621 + ent
->new_offset
+ 8);
1622 write_value (abfd
, buf
, value
, width
);
1629 /* The address calculation may overflow, giving us a
1630 value greater than 4G on a 32-bit target when
1631 dwarf_vma is 64-bit. */
1632 if (sizeof (address
) > 4 && ptr_size
== 4)
1633 address
&= 0xffffffff;
1634 hdr_info
->array
[hdr_info
->array_count
].initial_loc
= address
;
1635 hdr_info
->array
[hdr_info
->array_count
].range
1636 = read_value (abfd
, buf
+ width
, width
, FALSE
);
1637 hdr_info
->array
[hdr_info
->array_count
++].fde
1638 = (sec
->output_section
->vma
1639 + sec
->output_offset
1643 if ((ent
->lsda_encoding
& 0x70) == DW_EH_PE_pcrel
1644 || cie
->u
.cie
.make_lsda_relative
)
1646 buf
+= ent
->lsda_offset
;
1647 width
= get_DW_EH_PE_width (ent
->lsda_encoding
, ptr_size
);
1648 value
= read_value (abfd
, buf
, width
,
1649 get_DW_EH_PE_signed (ent
->lsda_encoding
));
1652 if ((ent
->lsda_encoding
& 0x70) == DW_EH_PE_pcrel
)
1653 value
+= (bfd_vma
) ent
->offset
- ent
->new_offset
;
1654 else if (cie
->u
.cie
.make_lsda_relative
)
1655 value
-= (sec
->output_section
->vma
1656 + sec
->output_offset
1657 + ent
->new_offset
+ 8 + ent
->lsda_offset
);
1658 write_value (abfd
, buf
, value
, width
);
1661 else if (ent
->add_augmentation_size
)
1663 /* Skip the PC and length and insert a zero byte for the
1664 augmentation size. */
1666 memmove (buf
+ 1, buf
, end
- buf
);
1672 /* Adjust DW_CFA_set_loc. */
1676 width
= get_DW_EH_PE_width (ent
->fde_encoding
, ptr_size
);
1677 new_offset
= ent
->new_offset
+ 8
1678 + extra_augmentation_string_bytes (ent
)
1679 + extra_augmentation_data_bytes (ent
);
1681 for (cnt
= 1; cnt
<= ent
->set_loc
[0]; cnt
++)
1683 buf
= start
+ ent
->set_loc
[cnt
];
1685 value
= read_value (abfd
, buf
, width
,
1686 get_DW_EH_PE_signed (ent
->fde_encoding
));
1690 if ((ent
->fde_encoding
& 0x70) == DW_EH_PE_pcrel
)
1691 value
+= (bfd_vma
) ent
->offset
+ 8 - new_offset
;
1692 if (ent
->make_relative
)
1693 value
-= (sec
->output_section
->vma
1694 + sec
->output_offset
1695 + new_offset
+ ent
->set_loc
[cnt
]);
1696 write_value (abfd
, buf
, value
, width
);
1702 /* We don't align the section to its section alignment since the
1703 runtime library only expects all CIE/FDE records aligned at
1704 the pointer size. _bfd_elf_discard_section_eh_frame should
1705 have padded CIE/FDE records to multiple of pointer size with
1706 size_of_output_cie_fde. */
1707 if ((sec
->size
% ptr_size
) != 0)
1710 /* FIXME: octets_per_byte. */
1711 return bfd_set_section_contents (abfd
, sec
->output_section
,
1712 contents
, (file_ptr
) sec
->output_offset
,
1716 /* Helper function used to sort .eh_frame_hdr search table by increasing
1717 VMA of FDE initial location. */
1720 vma_compare (const void *a
, const void *b
)
1722 const struct eh_frame_array_ent
*p
= (const struct eh_frame_array_ent
*) a
;
1723 const struct eh_frame_array_ent
*q
= (const struct eh_frame_array_ent
*) b
;
1724 if (p
->initial_loc
> q
->initial_loc
)
1726 if (p
->initial_loc
< q
->initial_loc
)
1731 /* Write out .eh_frame_hdr section. This must be called after
1732 _bfd_elf_write_section_eh_frame has been called on all input
1734 .eh_frame_hdr format:
1735 ubyte version (currently 1)
1736 ubyte eh_frame_ptr_enc (DW_EH_PE_* encoding of pointer to start of
1738 ubyte fde_count_enc (DW_EH_PE_* encoding of total FDE count
1739 number (or DW_EH_PE_omit if there is no
1740 binary search table computed))
1741 ubyte table_enc (DW_EH_PE_* encoding of binary search table,
1742 or DW_EH_PE_omit if not present.
1743 DW_EH_PE_datarel is using address of
1744 .eh_frame_hdr section start as base)
1745 [encoded] eh_frame_ptr (pointer to start of .eh_frame section)
1746 optionally followed by:
1747 [encoded] fde_count (total number of FDEs in .eh_frame section)
1748 fde_count x [encoded] initial_loc, fde
1749 (array of encoded pairs containing
1750 FDE initial_location field and FDE address,
1751 sorted by increasing initial_loc). */
1754 _bfd_elf_write_section_eh_frame_hdr (bfd
*abfd
, struct bfd_link_info
*info
)
1756 struct elf_link_hash_table
*htab
;
1757 struct eh_frame_hdr_info
*hdr_info
;
1759 bfd_boolean retval
= TRUE
;
1761 htab
= elf_hash_table (info
);
1762 hdr_info
= &htab
->eh_info
;
1763 sec
= hdr_info
->hdr_sec
;
1765 if (info
->eh_frame_hdr
&& sec
!= NULL
)
1768 asection
*eh_frame_sec
;
1770 bfd_vma encoded_eh_frame
;
1772 size
= EH_FRAME_HDR_SIZE
;
1773 if (hdr_info
->array
&& hdr_info
->array_count
== hdr_info
->fde_count
)
1774 size
+= 4 + hdr_info
->fde_count
* 8;
1775 contents
= (bfd_byte
*) bfd_malloc (size
);
1776 if (contents
== NULL
)
1779 eh_frame_sec
= bfd_get_section_by_name (abfd
, ".eh_frame");
1780 if (eh_frame_sec
== NULL
)
1786 memset (contents
, 0, EH_FRAME_HDR_SIZE
);
1789 /* .eh_frame offset. */
1790 contents
[1] = get_elf_backend_data (abfd
)->elf_backend_encode_eh_address
1791 (abfd
, info
, eh_frame_sec
, 0, sec
, 4, &encoded_eh_frame
);
1793 if (hdr_info
->array
&& hdr_info
->array_count
== hdr_info
->fde_count
)
1795 /* FDE count encoding. */
1796 contents
[2] = DW_EH_PE_udata4
;
1797 /* Search table encoding. */
1798 contents
[3] = DW_EH_PE_datarel
| DW_EH_PE_sdata4
;
1802 contents
[2] = DW_EH_PE_omit
;
1803 contents
[3] = DW_EH_PE_omit
;
1805 bfd_put_32 (abfd
, encoded_eh_frame
, contents
+ 4);
1807 if (contents
[2] != DW_EH_PE_omit
)
1810 bfd_boolean overlap
, overflow
;
1812 bfd_put_32 (abfd
, hdr_info
->fde_count
, contents
+ EH_FRAME_HDR_SIZE
);
1813 qsort (hdr_info
->array
, hdr_info
->fde_count
,
1814 sizeof (*hdr_info
->array
), vma_compare
);
1817 for (i
= 0; i
< hdr_info
->fde_count
; i
++)
1821 val
= hdr_info
->array
[i
].initial_loc
- sec
->output_section
->vma
;
1822 val
= ((val
& 0xffffffff) ^ 0x80000000) - 0x80000000;
1823 if (elf_elfheader (abfd
)->e_ident
[EI_CLASS
] == ELFCLASS64
1824 && (hdr_info
->array
[i
].initial_loc
1825 != sec
->output_section
->vma
+ val
))
1827 bfd_put_32 (abfd
, val
, contents
+ EH_FRAME_HDR_SIZE
+ i
* 8 + 4);
1828 val
= hdr_info
->array
[i
].fde
- sec
->output_section
->vma
;
1829 val
= ((val
& 0xffffffff) ^ 0x80000000) - 0x80000000;
1830 if (elf_elfheader (abfd
)->e_ident
[EI_CLASS
] == ELFCLASS64
1831 && (hdr_info
->array
[i
].fde
1832 != sec
->output_section
->vma
+ val
))
1834 bfd_put_32 (abfd
, val
, contents
+ EH_FRAME_HDR_SIZE
+ i
* 8 + 8);
1836 && (hdr_info
->array
[i
].initial_loc
1837 < (hdr_info
->array
[i
- 1].initial_loc
1838 + hdr_info
->array
[i
- 1].range
)))
1842 (*info
->callbacks
->einfo
)
1843 (_("%P: .eh_frame_hdr entry overflow.\n"));
1845 (*info
->callbacks
->einfo
)
1846 (_("%P: .eh_frame_hdr refers to overlapping FDEs.\n"));
1847 if (overflow
|| overlap
)
1849 bfd_set_error (bfd_error_bad_value
);
1854 /* FIXME: octets_per_byte. */
1855 if (!bfd_set_section_contents (abfd
, sec
->output_section
, contents
,
1856 (file_ptr
) sec
->output_offset
,
1861 if (hdr_info
->array
!= NULL
)
1862 free (hdr_info
->array
);
1866 /* Return the width of FDE addresses. This is the default implementation. */
1869 _bfd_elf_eh_frame_address_size (bfd
*abfd
, asection
*sec ATTRIBUTE_UNUSED
)
1871 return elf_elfheader (abfd
)->e_ident
[EI_CLASS
] == ELFCLASS64
? 8 : 4;
1874 /* Decide whether we can use a PC-relative encoding within the given
1875 EH frame section. This is the default implementation. */
1878 _bfd_elf_can_make_relative (bfd
*input_bfd ATTRIBUTE_UNUSED
,
1879 struct bfd_link_info
*info ATTRIBUTE_UNUSED
,
1880 asection
*eh_frame_section ATTRIBUTE_UNUSED
)
1885 /* Select an encoding for the given address. Preference is given to
1886 PC-relative addressing modes. */
1889 _bfd_elf_encode_eh_address (bfd
*abfd ATTRIBUTE_UNUSED
,
1890 struct bfd_link_info
*info ATTRIBUTE_UNUSED
,
1891 asection
*osec
, bfd_vma offset
,
1892 asection
*loc_sec
, bfd_vma loc_offset
,
1895 *encoded
= osec
->vma
+ offset
-
1896 (loc_sec
->output_section
->vma
+ loc_sec
->output_offset
+ loc_offset
);
1897 return DW_EH_PE_pcrel
| DW_EH_PE_sdata4
;