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- /* .eh_frame section optimization.
- Copyright (C) 2001-2022 Free Software Foundation, Inc.
- Written by Jakub Jelinek <jakub@redhat.com>.
- This file is part of BFD, the Binary File Descriptor library.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
- MA 02110-1301, USA. */
- #include "sysdep.h"
- #include "bfd.h"
- #include "libbfd.h"
- #include "elf-bfd.h"
- #include "dwarf2.h"
- #define EH_FRAME_HDR_SIZE 8
- struct cie
- {
- unsigned int length;
- unsigned int hash;
- unsigned char version;
- unsigned char local_personality;
- char augmentation[20];
- bfd_vma code_align;
- bfd_signed_vma data_align;
- bfd_vma ra_column;
- bfd_vma augmentation_size;
- union {
- struct elf_link_hash_entry *h;
- struct {
- unsigned int bfd_id;
- unsigned int index;
- } sym;
- unsigned int reloc_index;
- } personality;
- struct eh_cie_fde *cie_inf;
- unsigned char per_encoding;
- unsigned char lsda_encoding;
- unsigned char fde_encoding;
- unsigned char initial_insn_length;
- unsigned char can_make_lsda_relative;
- unsigned char initial_instructions[50];
- };
- /* If *ITER hasn't reached END yet, read the next byte into *RESULT and
- move onto the next byte. Return true on success. */
- static inline bool
- read_byte (bfd_byte **iter, bfd_byte *end, unsigned char *result)
- {
- if (*iter >= end)
- return false;
- *result = *((*iter)++);
- return true;
- }
- /* Move *ITER over LENGTH bytes, or up to END, whichever is closer.
- Return true it was possible to move LENGTH bytes. */
- static inline bool
- skip_bytes (bfd_byte **iter, bfd_byte *end, bfd_size_type length)
- {
- if ((bfd_size_type) (end - *iter) < length)
- {
- *iter = end;
- return false;
- }
- *iter += length;
- return true;
- }
- /* Move *ITER over an leb128, stopping at END. Return true if the end
- of the leb128 was found. */
- static bool
- skip_leb128 (bfd_byte **iter, bfd_byte *end)
- {
- unsigned char byte;
- do
- if (!read_byte (iter, end, &byte))
- return false;
- while (byte & 0x80);
- return true;
- }
- /* Like skip_leb128, but treat the leb128 as an unsigned value and
- store it in *VALUE. */
- static bool
- read_uleb128 (bfd_byte **iter, bfd_byte *end, bfd_vma *value)
- {
- bfd_byte *start, *p;
- start = *iter;
- if (!skip_leb128 (iter, end))
- return false;
- p = *iter;
- *value = *--p;
- while (p > start)
- *value = (*value << 7) | (*--p & 0x7f);
- return true;
- }
- /* Like read_uleb128, but for signed values. */
- static bool
- read_sleb128 (bfd_byte **iter, bfd_byte *end, bfd_signed_vma *value)
- {
- bfd_byte *start, *p;
- start = *iter;
- if (!skip_leb128 (iter, end))
- return false;
- p = *iter;
- *value = ((*--p & 0x7f) ^ 0x40) - 0x40;
- while (p > start)
- *value = (*value << 7) | (*--p & 0x7f);
- return true;
- }
- /* Return 0 if either encoding is variable width, or not yet known to bfd. */
- static
- int get_DW_EH_PE_width (int encoding, int ptr_size)
- {
- /* DW_EH_PE_ values of 0x60 and 0x70 weren't defined at the time .eh_frame
- was added to bfd. */
- if ((encoding & 0x60) == 0x60)
- return 0;
- switch (encoding & 7)
- {
- case DW_EH_PE_udata2: return 2;
- case DW_EH_PE_udata4: return 4;
- case DW_EH_PE_udata8: return 8;
- case DW_EH_PE_absptr: return ptr_size;
- default:
- break;
- }
- return 0;
- }
- #define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0)
- /* Read a width sized value from memory. */
- static bfd_vma
- read_value (bfd *abfd, bfd_byte *buf, int width, int is_signed)
- {
- bfd_vma value;
- switch (width)
- {
- case 2:
- if (is_signed)
- value = bfd_get_signed_16 (abfd, buf);
- else
- value = bfd_get_16 (abfd, buf);
- break;
- case 4:
- if (is_signed)
- value = bfd_get_signed_32 (abfd, buf);
- else
- value = bfd_get_32 (abfd, buf);
- break;
- case 8:
- if (is_signed)
- value = bfd_get_signed_64 (abfd, buf);
- else
- value = bfd_get_64 (abfd, buf);
- break;
- default:
- BFD_FAIL ();
- return 0;
- }
- return value;
- }
- /* Store a width sized value to memory. */
- static void
- write_value (bfd *abfd, bfd_byte *buf, bfd_vma value, int width)
- {
- switch (width)
- {
- case 2: bfd_put_16 (abfd, value, buf); break;
- case 4: bfd_put_32 (abfd, value, buf); break;
- case 8: bfd_put_64 (abfd, value, buf); break;
- default: BFD_FAIL ();
- }
- }
- /* Return one if C1 and C2 CIEs can be merged. */
- static int
- cie_eq (const void *e1, const void *e2)
- {
- const struct cie *c1 = (const struct cie *) e1;
- const struct cie *c2 = (const struct cie *) e2;
- if (c1->hash == c2->hash
- && c1->length == c2->length
- && c1->version == c2->version
- && c1->local_personality == c2->local_personality
- && strcmp (c1->augmentation, c2->augmentation) == 0
- && strcmp (c1->augmentation, "eh") != 0
- && c1->code_align == c2->code_align
- && c1->data_align == c2->data_align
- && c1->ra_column == c2->ra_column
- && c1->augmentation_size == c2->augmentation_size
- && memcmp (&c1->personality, &c2->personality,
- sizeof (c1->personality)) == 0
- && (c1->cie_inf->u.cie.u.sec->output_section
- == c2->cie_inf->u.cie.u.sec->output_section)
- && c1->per_encoding == c2->per_encoding
- && c1->lsda_encoding == c2->lsda_encoding
- && c1->fde_encoding == c2->fde_encoding
- && c1->initial_insn_length == c2->initial_insn_length
- && c1->initial_insn_length <= sizeof (c1->initial_instructions)
- && memcmp (c1->initial_instructions,
- c2->initial_instructions,
- c1->initial_insn_length) == 0)
- return 1;
- return 0;
- }
- static hashval_t
- cie_hash (const void *e)
- {
- const struct cie *c = (const struct cie *) e;
- return c->hash;
- }
- static hashval_t
- cie_compute_hash (struct cie *c)
- {
- hashval_t h = 0;
- size_t len;
- h = iterative_hash_object (c->length, h);
- h = iterative_hash_object (c->version, h);
- h = iterative_hash (c->augmentation, strlen (c->augmentation) + 1, h);
- h = iterative_hash_object (c->code_align, h);
- h = iterative_hash_object (c->data_align, h);
- h = iterative_hash_object (c->ra_column, h);
- h = iterative_hash_object (c->augmentation_size, h);
- h = iterative_hash_object (c->personality, h);
- h = iterative_hash_object (c->cie_inf->u.cie.u.sec->output_section, h);
- h = iterative_hash_object (c->per_encoding, h);
- h = iterative_hash_object (c->lsda_encoding, h);
- h = iterative_hash_object (c->fde_encoding, h);
- h = iterative_hash_object (c->initial_insn_length, h);
- len = c->initial_insn_length;
- if (len > sizeof (c->initial_instructions))
- len = sizeof (c->initial_instructions);
- h = iterative_hash (c->initial_instructions, len, h);
- c->hash = h;
- return h;
- }
- /* Return the number of extra bytes that we'll be inserting into
- ENTRY's augmentation string. */
- static inline unsigned int
- extra_augmentation_string_bytes (struct eh_cie_fde *entry)
- {
- unsigned int size = 0;
- if (entry->cie)
- {
- if (entry->add_augmentation_size)
- size++;
- if (entry->u.cie.add_fde_encoding)
- size++;
- }
- return size;
- }
- /* Likewise ENTRY's augmentation data. */
- static inline unsigned int
- extra_augmentation_data_bytes (struct eh_cie_fde *entry)
- {
- unsigned int size = 0;
- if (entry->add_augmentation_size)
- size++;
- if (entry->cie && entry->u.cie.add_fde_encoding)
- size++;
- return size;
- }
- /* Return the size that ENTRY will have in the output. */
- static unsigned int
- size_of_output_cie_fde (struct eh_cie_fde *entry)
- {
- if (entry->removed)
- return 0;
- if (entry->size == 4)
- return 4;
- return (entry->size
- + extra_augmentation_string_bytes (entry)
- + extra_augmentation_data_bytes (entry));
- }
- /* Return the offset of the FDE or CIE after ENT. */
- static unsigned int
- next_cie_fde_offset (const struct eh_cie_fde *ent,
- const struct eh_cie_fde *last,
- const asection *sec)
- {
- while (++ent < last)
- {
- if (!ent->removed)
- return ent->new_offset;
- }
- return sec->size;
- }
- /* Assume that the bytes between *ITER and END are CFA instructions.
- Try to move *ITER past the first instruction and return true on
- success. ENCODED_PTR_WIDTH gives the width of pointer entries. */
- static bool
- skip_cfa_op (bfd_byte **iter, bfd_byte *end, unsigned int encoded_ptr_width)
- {
- bfd_byte op;
- bfd_vma length;
- if (!read_byte (iter, end, &op))
- return false;
- switch (op & 0xc0 ? op & 0xc0 : op)
- {
- case DW_CFA_nop:
- case DW_CFA_advance_loc:
- case DW_CFA_restore:
- case DW_CFA_remember_state:
- case DW_CFA_restore_state:
- case DW_CFA_GNU_window_save:
- /* No arguments. */
- return true;
- case DW_CFA_offset:
- case DW_CFA_restore_extended:
- case DW_CFA_undefined:
- case DW_CFA_same_value:
- case DW_CFA_def_cfa_register:
- case DW_CFA_def_cfa_offset:
- case DW_CFA_def_cfa_offset_sf:
- case DW_CFA_GNU_args_size:
- /* One leb128 argument. */
- return skip_leb128 (iter, end);
- case DW_CFA_val_offset:
- case DW_CFA_val_offset_sf:
- case DW_CFA_offset_extended:
- case DW_CFA_register:
- case DW_CFA_def_cfa:
- case DW_CFA_offset_extended_sf:
- case DW_CFA_GNU_negative_offset_extended:
- case DW_CFA_def_cfa_sf:
- /* Two leb128 arguments. */
- return (skip_leb128 (iter, end)
- && skip_leb128 (iter, end));
- case DW_CFA_def_cfa_expression:
- /* A variable-length argument. */
- return (read_uleb128 (iter, end, &length)
- && skip_bytes (iter, end, length));
- case DW_CFA_expression:
- case DW_CFA_val_expression:
- /* A leb128 followed by a variable-length argument. */
- return (skip_leb128 (iter, end)
- && read_uleb128 (iter, end, &length)
- && skip_bytes (iter, end, length));
- case DW_CFA_set_loc:
- return skip_bytes (iter, end, encoded_ptr_width);
- case DW_CFA_advance_loc1:
- return skip_bytes (iter, end, 1);
- case DW_CFA_advance_loc2:
- return skip_bytes (iter, end, 2);
- case DW_CFA_advance_loc4:
- return skip_bytes (iter, end, 4);
- case DW_CFA_MIPS_advance_loc8:
- return skip_bytes (iter, end, 8);
- default:
- return false;
- }
- }
- /* Try to interpret the bytes between BUF and END as CFA instructions.
- If every byte makes sense, return a pointer to the first DW_CFA_nop
- padding byte, or END if there is no padding. Return null otherwise.
- ENCODED_PTR_WIDTH is as for skip_cfa_op. */
- static bfd_byte *
- skip_non_nops (bfd_byte *buf, bfd_byte *end, unsigned int encoded_ptr_width,
- unsigned int *set_loc_count)
- {
- bfd_byte *last;
- last = buf;
- while (buf < end)
- if (*buf == DW_CFA_nop)
- buf++;
- else
- {
- if (*buf == DW_CFA_set_loc)
- ++*set_loc_count;
- if (!skip_cfa_op (&buf, end, encoded_ptr_width))
- return 0;
- last = buf;
- }
- return last;
- }
- /* Convert absolute encoding ENCODING into PC-relative form.
- SIZE is the size of a pointer. */
- static unsigned char
- make_pc_relative (unsigned char encoding, unsigned int ptr_size)
- {
- if ((encoding & 0x7f) == DW_EH_PE_absptr)
- switch (ptr_size)
- {
- case 2:
- encoding |= DW_EH_PE_sdata2;
- break;
- case 4:
- encoding |= DW_EH_PE_sdata4;
- break;
- case 8:
- encoding |= DW_EH_PE_sdata8;
- break;
- }
- return encoding | DW_EH_PE_pcrel;
- }
- /* Examine each .eh_frame_entry section and discard those
- those that are marked SEC_EXCLUDE. */
- static void
- bfd_elf_discard_eh_frame_entry (struct eh_frame_hdr_info *hdr_info)
- {
- unsigned int i;
- for (i = 0; i < hdr_info->array_count; i++)
- {
- if (hdr_info->u.compact.entries[i]->flags & SEC_EXCLUDE)
- {
- unsigned int j;
- for (j = i + 1; j < hdr_info->array_count; j++)
- hdr_info->u.compact.entries[j-1] = hdr_info->u.compact.entries[j];
- hdr_info->array_count--;
- hdr_info->u.compact.entries[hdr_info->array_count] = NULL;
- i--;
- }
- }
- }
- /* Add a .eh_frame_entry section. */
- static void
- bfd_elf_record_eh_frame_entry (struct eh_frame_hdr_info *hdr_info,
- asection *sec)
- {
- if (hdr_info->array_count == hdr_info->u.compact.allocated_entries)
- {
- if (hdr_info->u.compact.allocated_entries == 0)
- {
- hdr_info->frame_hdr_is_compact = true;
- hdr_info->u.compact.allocated_entries = 2;
- hdr_info->u.compact.entries =
- bfd_malloc (hdr_info->u.compact.allocated_entries
- * sizeof (hdr_info->u.compact.entries[0]));
- }
- else
- {
- hdr_info->u.compact.allocated_entries *= 2;
- hdr_info->u.compact.entries =
- bfd_realloc (hdr_info->u.compact.entries,
- hdr_info->u.compact.allocated_entries
- * sizeof (hdr_info->u.compact.entries[0]));
- }
- BFD_ASSERT (hdr_info->u.compact.entries);
- }
- hdr_info->u.compact.entries[hdr_info->array_count++] = sec;
- }
- /* Parse a .eh_frame_entry section. Figure out which text section it
- references. */
- bool
- _bfd_elf_parse_eh_frame_entry (struct bfd_link_info *info,
- asection *sec, struct elf_reloc_cookie *cookie)
- {
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- unsigned long r_symndx;
- asection *text_sec;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- if (sec->size == 0
- || sec->sec_info_type != SEC_INFO_TYPE_NONE)
- {
- return true;
- }
- if (sec->output_section && bfd_is_abs_section (sec->output_section))
- {
- /* At least one of the sections is being discarded from the
- link, so we should just ignore them. */
- return true;
- }
- if (cookie->rel == cookie->relend)
- return false;
- /* The first relocation is the function start. */
- r_symndx = cookie->rel->r_info >> cookie->r_sym_shift;
- if (r_symndx == STN_UNDEF)
- return false;
- text_sec = _bfd_elf_section_for_symbol (cookie, r_symndx, false);
- if (text_sec == NULL)
- return false;
- elf_section_eh_frame_entry (text_sec) = sec;
- if (text_sec->output_section
- && bfd_is_abs_section (text_sec->output_section))
- sec->flags |= SEC_EXCLUDE;
- sec->sec_info_type = SEC_INFO_TYPE_EH_FRAME_ENTRY;
- elf_section_data (sec)->sec_info = text_sec;
- bfd_elf_record_eh_frame_entry (hdr_info, sec);
- return true;
- }
- /* Try to parse .eh_frame section SEC, which belongs to ABFD. Store the
- information in the section's sec_info field on success. COOKIE
- describes the relocations in SEC. */
- void
- _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
- asection *sec, struct elf_reloc_cookie *cookie)
- {
- #define REQUIRE(COND) \
- do \
- if (!(COND)) \
- goto free_no_table; \
- while (0)
- bfd_byte *ehbuf = NULL, *buf, *end;
- bfd_byte *last_fde;
- struct eh_cie_fde *this_inf;
- unsigned int hdr_length, hdr_id;
- unsigned int cie_count;
- struct cie *cie, *local_cies = NULL;
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- struct eh_frame_sec_info *sec_info = NULL;
- unsigned int ptr_size;
- unsigned int num_cies;
- unsigned int num_entries;
- elf_gc_mark_hook_fn gc_mark_hook;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- if (sec->size == 0
- || sec->sec_info_type != SEC_INFO_TYPE_NONE)
- {
- /* This file does not contain .eh_frame information. */
- return;
- }
- if (bfd_is_abs_section (sec->output_section))
- {
- /* At least one of the sections is being discarded from the
- link, so we should just ignore them. */
- return;
- }
- /* Read the frame unwind information from abfd. */
- REQUIRE (bfd_malloc_and_get_section (abfd, sec, &ehbuf));
- /* If .eh_frame section size doesn't fit into int, we cannot handle
- it (it would need to use 64-bit .eh_frame format anyway). */
- REQUIRE (sec->size == (unsigned int) sec->size);
- ptr_size = (get_elf_backend_data (abfd)
- ->elf_backend_eh_frame_address_size (abfd, sec));
- REQUIRE (ptr_size != 0);
- /* Go through the section contents and work out how many FDEs and
- CIEs there are. */
- buf = ehbuf;
- end = ehbuf + sec->size;
- num_cies = 0;
- num_entries = 0;
- while (buf != end)
- {
- num_entries++;
- /* Read the length of the entry. */
- REQUIRE (skip_bytes (&buf, end, 4));
- hdr_length = bfd_get_32 (abfd, buf - 4);
- /* 64-bit .eh_frame is not supported. */
- REQUIRE (hdr_length != 0xffffffff);
- if (hdr_length == 0)
- break;
- REQUIRE (skip_bytes (&buf, end, 4));
- hdr_id = bfd_get_32 (abfd, buf - 4);
- if (hdr_id == 0)
- num_cies++;
- REQUIRE (skip_bytes (&buf, end, hdr_length - 4));
- }
- sec_info = (struct eh_frame_sec_info *)
- bfd_zmalloc (sizeof (struct eh_frame_sec_info)
- + (num_entries - 1) * sizeof (struct eh_cie_fde));
- REQUIRE (sec_info);
- /* We need to have a "struct cie" for each CIE in this section. */
- if (num_cies)
- {
- local_cies = (struct cie *) bfd_zmalloc (num_cies * sizeof (*local_cies));
- REQUIRE (local_cies);
- }
- /* FIXME: octets_per_byte. */
- #define ENSURE_NO_RELOCS(buf) \
- while (cookie->rel < cookie->relend \
- && (cookie->rel->r_offset \
- < (bfd_size_type) ((buf) - ehbuf))) \
- { \
- REQUIRE (cookie->rel->r_info == 0); \
- cookie->rel++; \
- }
- /* FIXME: octets_per_byte. */
- #define SKIP_RELOCS(buf) \
- while (cookie->rel < cookie->relend \
- && (cookie->rel->r_offset \
- < (bfd_size_type) ((buf) - ehbuf))) \
- cookie->rel++
- /* FIXME: octets_per_byte. */
- #define GET_RELOC(buf) \
- ((cookie->rel < cookie->relend \
- && (cookie->rel->r_offset \
- == (bfd_size_type) ((buf) - ehbuf))) \
- ? cookie->rel : NULL)
- buf = ehbuf;
- cie_count = 0;
- gc_mark_hook = get_elf_backend_data (abfd)->gc_mark_hook;
- while ((bfd_size_type) (buf - ehbuf) != sec->size)
- {
- char *aug;
- bfd_byte *start, *insns, *insns_end;
- bfd_size_type length;
- unsigned int set_loc_count;
- this_inf = sec_info->entry + sec_info->count;
- last_fde = buf;
- /* Read the length of the entry. */
- REQUIRE (skip_bytes (&buf, ehbuf + sec->size, 4));
- hdr_length = bfd_get_32 (abfd, buf - 4);
- /* The CIE/FDE must be fully contained in this input section. */
- REQUIRE ((bfd_size_type) (buf - ehbuf) + hdr_length <= sec->size);
- end = buf + hdr_length;
- this_inf->offset = last_fde - ehbuf;
- this_inf->size = 4 + hdr_length;
- this_inf->reloc_index = cookie->rel - cookie->rels;
- if (hdr_length == 0)
- {
- /* A zero-length CIE should only be found at the end of
- the section, but allow multiple terminators. */
- while (skip_bytes (&buf, ehbuf + sec->size, 4))
- REQUIRE (bfd_get_32 (abfd, buf - 4) == 0);
- REQUIRE ((bfd_size_type) (buf - ehbuf) == sec->size);
- ENSURE_NO_RELOCS (buf);
- sec_info->count++;
- break;
- }
- REQUIRE (skip_bytes (&buf, end, 4));
- hdr_id = bfd_get_32 (abfd, buf - 4);
- if (hdr_id == 0)
- {
- unsigned int initial_insn_length;
- /* CIE */
- this_inf->cie = 1;
- /* Point CIE to one of the section-local cie structures. */
- cie = local_cies + cie_count++;
- cie->cie_inf = this_inf;
- cie->length = hdr_length;
- start = buf;
- REQUIRE (read_byte (&buf, end, &cie->version));
- /* Cannot handle unknown versions. */
- REQUIRE (cie->version == 1
- || cie->version == 3
- || cie->version == 4);
- REQUIRE (strlen ((char *) buf) < sizeof (cie->augmentation));
- strcpy (cie->augmentation, (char *) buf);
- buf = (bfd_byte *) strchr ((char *) buf, '\0') + 1;
- this_inf->u.cie.aug_str_len = buf - start - 1;
- ENSURE_NO_RELOCS (buf);
- if (buf[0] == 'e' && buf[1] == 'h')
- {
- /* GCC < 3.0 .eh_frame CIE */
- /* We cannot merge "eh" CIEs because __EXCEPTION_TABLE__
- is private to each CIE, so we don't need it for anything.
- Just skip it. */
- REQUIRE (skip_bytes (&buf, end, ptr_size));
- SKIP_RELOCS (buf);
- }
- if (cie->version >= 4)
- {
- REQUIRE (buf + 1 < end);
- REQUIRE (buf[0] == ptr_size);
- REQUIRE (buf[1] == 0);
- buf += 2;
- }
- REQUIRE (read_uleb128 (&buf, end, &cie->code_align));
- REQUIRE (read_sleb128 (&buf, end, &cie->data_align));
- if (cie->version == 1)
- {
- REQUIRE (buf < end);
- cie->ra_column = *buf++;
- }
- else
- REQUIRE (read_uleb128 (&buf, end, &cie->ra_column));
- ENSURE_NO_RELOCS (buf);
- cie->lsda_encoding = DW_EH_PE_omit;
- cie->fde_encoding = DW_EH_PE_omit;
- cie->per_encoding = DW_EH_PE_omit;
- aug = cie->augmentation;
- if (aug[0] != 'e' || aug[1] != 'h')
- {
- if (*aug == 'z')
- {
- aug++;
- REQUIRE (read_uleb128 (&buf, end, &cie->augmentation_size));
- ENSURE_NO_RELOCS (buf);
- }
- while (*aug != '\0')
- switch (*aug++)
- {
- case 'B':
- break;
- case 'L':
- REQUIRE (read_byte (&buf, end, &cie->lsda_encoding));
- ENSURE_NO_RELOCS (buf);
- REQUIRE (get_DW_EH_PE_width (cie->lsda_encoding, ptr_size));
- break;
- case 'R':
- REQUIRE (read_byte (&buf, end, &cie->fde_encoding));
- ENSURE_NO_RELOCS (buf);
- REQUIRE (get_DW_EH_PE_width (cie->fde_encoding, ptr_size));
- break;
- case 'S':
- break;
- case 'P':
- {
- int per_width;
- REQUIRE (read_byte (&buf, end, &cie->per_encoding));
- per_width = get_DW_EH_PE_width (cie->per_encoding,
- ptr_size);
- REQUIRE (per_width);
- if ((cie->per_encoding & 0x70) == DW_EH_PE_aligned)
- {
- length = -(buf - ehbuf) & (per_width - 1);
- REQUIRE (skip_bytes (&buf, end, length));
- if (per_width == 8)
- this_inf->u.cie.per_encoding_aligned8 = 1;
- }
- this_inf->u.cie.personality_offset = buf - start;
- ENSURE_NO_RELOCS (buf);
- /* Ensure we have a reloc here. */
- REQUIRE (GET_RELOC (buf));
- cie->personality.reloc_index
- = cookie->rel - cookie->rels;
- /* Cope with MIPS-style composite relocations. */
- do
- cookie->rel++;
- while (GET_RELOC (buf) != NULL);
- REQUIRE (skip_bytes (&buf, end, per_width));
- }
- break;
- default:
- /* Unrecognized augmentation. Better bail out. */
- goto free_no_table;
- }
- }
- this_inf->u.cie.aug_data_len
- = buf - start - 1 - this_inf->u.cie.aug_str_len;
- /* For shared libraries, try to get rid of as many RELATIVE relocs
- as possible. */
- if (bfd_link_pic (info)
- && (get_elf_backend_data (abfd)
- ->elf_backend_can_make_relative_eh_frame
- (abfd, info, sec)))
- {
- if ((cie->fde_encoding & 0x70) == DW_EH_PE_absptr)
- this_inf->make_relative = 1;
- /* If the CIE doesn't already have an 'R' entry, it's fairly
- easy to add one, provided that there's no aligned data
- after the augmentation string. */
- else if (cie->fde_encoding == DW_EH_PE_omit
- && (cie->per_encoding & 0x70) != DW_EH_PE_aligned)
- {
- if (*cie->augmentation == 0)
- this_inf->add_augmentation_size = 1;
- this_inf->u.cie.add_fde_encoding = 1;
- this_inf->make_relative = 1;
- }
- if ((cie->lsda_encoding & 0x70) == DW_EH_PE_absptr)
- cie->can_make_lsda_relative = 1;
- }
- /* If FDE encoding was not specified, it defaults to
- DW_EH_absptr. */
- if (cie->fde_encoding == DW_EH_PE_omit)
- cie->fde_encoding = DW_EH_PE_absptr;
- initial_insn_length = end - buf;
- cie->initial_insn_length = initial_insn_length;
- memcpy (cie->initial_instructions, buf,
- initial_insn_length <= sizeof (cie->initial_instructions)
- ? initial_insn_length : sizeof (cie->initial_instructions));
- insns = buf;
- buf += initial_insn_length;
- ENSURE_NO_RELOCS (buf);
- if (!bfd_link_relocatable (info))
- {
- /* Keep info for merging cies. */
- this_inf->u.cie.u.full_cie = cie;
- this_inf->u.cie.per_encoding_relative
- = (cie->per_encoding & 0x70) == DW_EH_PE_pcrel;
- }
- }
- else
- {
- /* Find the corresponding CIE. */
- unsigned int cie_offset = this_inf->offset + 4 - hdr_id;
- for (cie = local_cies; cie < local_cies + cie_count; cie++)
- if (cie_offset == cie->cie_inf->offset)
- break;
- /* Ensure this FDE references one of the CIEs in this input
- section. */
- REQUIRE (cie != local_cies + cie_count);
- this_inf->u.fde.cie_inf = cie->cie_inf;
- this_inf->make_relative = cie->cie_inf->make_relative;
- this_inf->add_augmentation_size
- = cie->cie_inf->add_augmentation_size;
- ENSURE_NO_RELOCS (buf);
- if ((sec->flags & SEC_LINKER_CREATED) == 0 || cookie->rels != NULL)
- {
- asection *rsec;
- REQUIRE (GET_RELOC (buf));
- /* Chain together the FDEs for each section. */
- rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook,
- cookie, NULL);
- /* RSEC will be NULL if FDE was cleared out as it was belonging to
- a discarded SHT_GROUP. */
- if (rsec)
- {
- REQUIRE (rsec->owner == abfd);
- this_inf->u.fde.next_for_section = elf_fde_list (rsec);
- elf_fde_list (rsec) = this_inf;
- }
- }
- /* Skip the initial location and address range. */
- start = buf;
- length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size);
- REQUIRE (skip_bytes (&buf, end, 2 * length));
- SKIP_RELOCS (buf - length);
- if (!GET_RELOC (buf - length)
- && read_value (abfd, buf - length, length, false) == 0)
- {
- (*info->callbacks->minfo)
- /* xgettext:c-format */
- (_("discarding zero address range FDE in %pB(%pA).\n"),
- abfd, sec);
- this_inf->u.fde.cie_inf = NULL;
- }
- /* Skip the augmentation size, if present. */
- if (cie->augmentation[0] == 'z')
- REQUIRE (read_uleb128 (&buf, end, &length));
- else
- length = 0;
- /* Of the supported augmentation characters above, only 'L'
- adds augmentation data to the FDE. This code would need to
- be adjusted if any future augmentations do the same thing. */
- if (cie->lsda_encoding != DW_EH_PE_omit)
- {
- SKIP_RELOCS (buf);
- if (cie->can_make_lsda_relative && GET_RELOC (buf))
- cie->cie_inf->u.cie.make_lsda_relative = 1;
- this_inf->lsda_offset = buf - start;
- /* If there's no 'z' augmentation, we don't know where the
- CFA insns begin. Assume no padding. */
- if (cie->augmentation[0] != 'z')
- length = end - buf;
- }
- /* Skip over the augmentation data. */
- REQUIRE (skip_bytes (&buf, end, length));
- insns = buf;
- buf = last_fde + 4 + hdr_length;
- /* For NULL RSEC (cleared FDE belonging to a discarded section)
- the relocations are commonly cleared. We do not sanity check if
- all these relocations are cleared as (1) relocations to
- .gcc_except_table will remain uncleared (they will get dropped
- with the drop of this unused FDE) and (2) BFD already safely drops
- relocations of any type to .eh_frame by
- elf_section_ignore_discarded_relocs.
- TODO: The .gcc_except_table entries should be also filtered as
- .eh_frame entries; or GCC could rather use COMDAT for them. */
- SKIP_RELOCS (buf);
- }
- /* Try to interpret the CFA instructions and find the first
- padding nop. Shrink this_inf's size so that it doesn't
- include the padding. */
- length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size);
- set_loc_count = 0;
- insns_end = skip_non_nops (insns, end, length, &set_loc_count);
- /* If we don't understand the CFA instructions, we can't know
- what needs to be adjusted there. */
- if (insns_end == NULL
- /* For the time being we don't support DW_CFA_set_loc in
- CIE instructions. */
- || (set_loc_count && this_inf->cie))
- goto free_no_table;
- this_inf->size -= end - insns_end;
- if (insns_end != end && this_inf->cie)
- {
- cie->initial_insn_length -= end - insns_end;
- cie->length -= end - insns_end;
- }
- if (set_loc_count
- && ((cie->fde_encoding & 0x70) == DW_EH_PE_pcrel
- || this_inf->make_relative))
- {
- unsigned int cnt;
- bfd_byte *p;
- this_inf->set_loc = (unsigned int *)
- bfd_malloc ((set_loc_count + 1) * sizeof (unsigned int));
- REQUIRE (this_inf->set_loc);
- this_inf->set_loc[0] = set_loc_count;
- p = insns;
- cnt = 0;
- while (p < end)
- {
- if (*p == DW_CFA_set_loc)
- this_inf->set_loc[++cnt] = p + 1 - start;
- REQUIRE (skip_cfa_op (&p, end, length));
- }
- }
- this_inf->removed = 1;
- this_inf->fde_encoding = cie->fde_encoding;
- this_inf->lsda_encoding = cie->lsda_encoding;
- sec_info->count++;
- }
- BFD_ASSERT (sec_info->count == num_entries);
- BFD_ASSERT (cie_count == num_cies);
- elf_section_data (sec)->sec_info = sec_info;
- sec->sec_info_type = SEC_INFO_TYPE_EH_FRAME;
- if (!bfd_link_relocatable (info))
- {
- /* Keep info for merging cies. */
- sec_info->cies = local_cies;
- local_cies = NULL;
- }
- goto success;
- free_no_table:
- _bfd_error_handler
- /* xgettext:c-format */
- (_("error in %pB(%pA); no .eh_frame_hdr table will be created"),
- abfd, sec);
- hdr_info->u.dwarf.table = false;
- free (sec_info);
- success:
- free (ehbuf);
- free (local_cies);
- #undef REQUIRE
- }
- /* Order eh_frame_hdr entries by the VMA of their text section. */
- static int
- cmp_eh_frame_hdr (const void *a, const void *b)
- {
- bfd_vma text_a;
- bfd_vma text_b;
- asection *sec;
- sec = *(asection *const *)a;
- sec = (asection *) elf_section_data (sec)->sec_info;
- text_a = sec->output_section->vma + sec->output_offset;
- sec = *(asection *const *)b;
- sec = (asection *) elf_section_data (sec)->sec_info;
- text_b = sec->output_section->vma + sec->output_offset;
- if (text_a < text_b)
- return -1;
- return text_a > text_b;
- }
- /* Add space for a CANTUNWIND terminator to SEC if the text sections
- referenced by it and NEXT are not contiguous, or NEXT is NULL. */
- static void
- add_eh_frame_hdr_terminator (asection *sec,
- asection *next)
- {
- bfd_vma end;
- bfd_vma next_start;
- asection *text_sec;
- if (next)
- {
- /* See if there is a gap (presumably a text section without unwind info)
- between these two entries. */
- text_sec = (asection *) elf_section_data (sec)->sec_info;
- end = text_sec->output_section->vma + text_sec->output_offset
- + text_sec->size;
- text_sec = (asection *) elf_section_data (next)->sec_info;
- next_start = text_sec->output_section->vma + text_sec->output_offset;
- if (end == next_start)
- return;
- }
- /* Add space for a CANTUNWIND terminator. */
- if (!sec->rawsize)
- sec->rawsize = sec->size;
- bfd_set_section_size (sec, sec->size + 8);
- }
- /* Finish a pass over all .eh_frame_entry sections. */
- bool
- _bfd_elf_end_eh_frame_parsing (struct bfd_link_info *info)
- {
- struct eh_frame_hdr_info *hdr_info;
- unsigned int i;
- hdr_info = &elf_hash_table (info)->eh_info;
- if (info->eh_frame_hdr_type != COMPACT_EH_HDR
- || hdr_info->array_count == 0)
- return false;
- bfd_elf_discard_eh_frame_entry (hdr_info);
- qsort (hdr_info->u.compact.entries, hdr_info->array_count,
- sizeof (asection *), cmp_eh_frame_hdr);
- for (i = 0; i < hdr_info->array_count - 1; i++)
- {
- add_eh_frame_hdr_terminator (hdr_info->u.compact.entries[i],
- hdr_info->u.compact.entries[i + 1]);
- }
- /* Add a CANTUNWIND terminator after the last entry. */
- add_eh_frame_hdr_terminator (hdr_info->u.compact.entries[i], NULL);
- return true;
- }
- /* Mark all relocations against CIE or FDE ENT, which occurs in
- .eh_frame section SEC. COOKIE describes the relocations in SEC;
- its "rel" field can be changed freely. */
- static bool
- mark_entry (struct bfd_link_info *info, asection *sec,
- struct eh_cie_fde *ent, elf_gc_mark_hook_fn gc_mark_hook,
- struct elf_reloc_cookie *cookie)
- {
- /* FIXME: octets_per_byte. */
- for (cookie->rel = cookie->rels + ent->reloc_index;
- cookie->rel < cookie->relend
- && cookie->rel->r_offset < ent->offset + ent->size;
- cookie->rel++)
- if (!_bfd_elf_gc_mark_reloc (info, sec, gc_mark_hook, cookie))
- return false;
- return true;
- }
- /* Mark all the relocations against FDEs that relate to code in input
- section SEC. The FDEs belong to .eh_frame section EH_FRAME, whose
- relocations are described by COOKIE. */
- bool
- _bfd_elf_gc_mark_fdes (struct bfd_link_info *info, asection *sec,
- asection *eh_frame, elf_gc_mark_hook_fn gc_mark_hook,
- struct elf_reloc_cookie *cookie)
- {
- struct eh_cie_fde *fde, *cie;
- for (fde = elf_fde_list (sec); fde; fde = fde->u.fde.next_for_section)
- {
- if (!mark_entry (info, eh_frame, fde, gc_mark_hook, cookie))
- return false;
- /* At this stage, all cie_inf fields point to local CIEs, so we
- can use the same cookie to refer to them. */
- cie = fde->u.fde.cie_inf;
- if (cie != NULL && !cie->u.cie.gc_mark)
- {
- cie->u.cie.gc_mark = 1;
- if (!mark_entry (info, eh_frame, cie, gc_mark_hook, cookie))
- return false;
- }
- }
- return true;
- }
- /* Input section SEC of ABFD is an .eh_frame section that contains the
- CIE described by CIE_INF. Return a version of CIE_INF that is going
- to be kept in the output, adding CIE_INF to the output if necessary.
- HDR_INFO is the .eh_frame_hdr information and COOKIE describes the
- relocations in REL. */
- static struct eh_cie_fde *
- find_merged_cie (bfd *abfd, struct bfd_link_info *info, asection *sec,
- struct eh_frame_hdr_info *hdr_info,
- struct elf_reloc_cookie *cookie,
- struct eh_cie_fde *cie_inf)
- {
- unsigned long r_symndx;
- struct cie *cie, *new_cie;
- Elf_Internal_Rela *rel;
- void **loc;
- /* Use CIE_INF if we have already decided to keep it. */
- if (!cie_inf->removed)
- return cie_inf;
- /* If we have merged CIE_INF with another CIE, use that CIE instead. */
- if (cie_inf->u.cie.merged)
- return cie_inf->u.cie.u.merged_with;
- cie = cie_inf->u.cie.u.full_cie;
- /* Assume we will need to keep CIE_INF. */
- cie_inf->removed = 0;
- cie_inf->u.cie.u.sec = sec;
- /* If we are not merging CIEs, use CIE_INF. */
- if (cie == NULL)
- return cie_inf;
- if (cie->per_encoding != DW_EH_PE_omit)
- {
- bool per_binds_local;
- /* Work out the address of personality routine, or at least
- enough info that we could calculate the address had we made a
- final section layout. The symbol on the reloc is enough,
- either the hash for a global, or (bfd id, index) pair for a
- local. The assumption here is that no one uses addends on
- the reloc. */
- rel = cookie->rels + cie->personality.reloc_index;
- memset (&cie->personality, 0, sizeof (cie->personality));
- #ifdef BFD64
- if (elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64)
- r_symndx = ELF64_R_SYM (rel->r_info);
- else
- #endif
- r_symndx = ELF32_R_SYM (rel->r_info);
- if (r_symndx >= cookie->locsymcount
- || ELF_ST_BIND (cookie->locsyms[r_symndx].st_info) != STB_LOCAL)
- {
- struct elf_link_hash_entry *h;
- r_symndx -= cookie->extsymoff;
- h = cookie->sym_hashes[r_symndx];
- while (h->root.type == bfd_link_hash_indirect
- || h->root.type == bfd_link_hash_warning)
- h = (struct elf_link_hash_entry *) h->root.u.i.link;
- cie->personality.h = h;
- per_binds_local = SYMBOL_REFERENCES_LOCAL (info, h);
- }
- else
- {
- Elf_Internal_Sym *sym;
- asection *sym_sec;
- sym = &cookie->locsyms[r_symndx];
- sym_sec = bfd_section_from_elf_index (abfd, sym->st_shndx);
- if (sym_sec == NULL)
- return cie_inf;
- if (sym_sec->kept_section != NULL)
- sym_sec = sym_sec->kept_section;
- if (sym_sec->output_section == NULL)
- return cie_inf;
- cie->local_personality = 1;
- cie->personality.sym.bfd_id = abfd->id;
- cie->personality.sym.index = r_symndx;
- per_binds_local = true;
- }
- if (per_binds_local
- && bfd_link_pic (info)
- && (cie->per_encoding & 0x70) == DW_EH_PE_absptr
- && (get_elf_backend_data (abfd)
- ->elf_backend_can_make_relative_eh_frame (abfd, info, sec)))
- {
- cie_inf->u.cie.make_per_encoding_relative = 1;
- cie_inf->u.cie.per_encoding_relative = 1;
- }
- }
- /* See if we can merge this CIE with an earlier one. */
- cie_compute_hash (cie);
- if (hdr_info->u.dwarf.cies == NULL)
- {
- hdr_info->u.dwarf.cies = htab_try_create (1, cie_hash, cie_eq, free);
- if (hdr_info->u.dwarf.cies == NULL)
- return cie_inf;
- }
- loc = htab_find_slot_with_hash (hdr_info->u.dwarf.cies, cie,
- cie->hash, INSERT);
- if (loc == NULL)
- return cie_inf;
- new_cie = (struct cie *) *loc;
- if (new_cie == NULL)
- {
- /* Keep CIE_INF and record it in the hash table. */
- new_cie = (struct cie *) malloc (sizeof (struct cie));
- if (new_cie == NULL)
- return cie_inf;
- memcpy (new_cie, cie, sizeof (struct cie));
- *loc = new_cie;
- }
- else
- {
- /* Merge CIE_INF with NEW_CIE->CIE_INF. */
- cie_inf->removed = 1;
- cie_inf->u.cie.merged = 1;
- cie_inf->u.cie.u.merged_with = new_cie->cie_inf;
- if (cie_inf->u.cie.make_lsda_relative)
- new_cie->cie_inf->u.cie.make_lsda_relative = 1;
- }
- return new_cie->cie_inf;
- }
- /* For a given OFFSET in SEC, return the delta to the new location
- after .eh_frame editing. */
- static bfd_signed_vma
- offset_adjust (bfd_vma offset, const asection *sec)
- {
- struct eh_frame_sec_info *sec_info
- = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info;
- unsigned int lo, hi, mid;
- struct eh_cie_fde *ent = NULL;
- bfd_signed_vma delta;
- lo = 0;
- hi = sec_info->count;
- if (hi == 0)
- return 0;
- while (lo < hi)
- {
- mid = (lo + hi) / 2;
- ent = &sec_info->entry[mid];
- if (offset < ent->offset)
- hi = mid;
- else if (mid + 1 >= hi)
- break;
- else if (offset >= ent[1].offset)
- lo = mid + 1;
- else
- break;
- }
- if (!ent->removed)
- delta = (bfd_vma) ent->new_offset - (bfd_vma) ent->offset;
- else if (ent->cie && ent->u.cie.merged)
- {
- struct eh_cie_fde *cie = ent->u.cie.u.merged_with;
- delta = ((bfd_vma) cie->new_offset + cie->u.cie.u.sec->output_offset
- - (bfd_vma) ent->offset - sec->output_offset);
- }
- else
- {
- /* Is putting the symbol on the next entry best for a deleted
- CIE/FDE? */
- struct eh_cie_fde *last = sec_info->entry + sec_info->count;
- delta = ((bfd_vma) next_cie_fde_offset (ent, last, sec)
- - (bfd_vma) ent->offset);
- return delta;
- }
- /* Account for editing within this CIE/FDE. */
- offset -= ent->offset;
- if (ent->cie)
- {
- unsigned int extra
- = ent->add_augmentation_size + ent->u.cie.add_fde_encoding;
- if (extra == 0
- || offset <= 9u + ent->u.cie.aug_str_len)
- return delta;
- delta += extra;
- if (offset <= 9u + ent->u.cie.aug_str_len + ent->u.cie.aug_data_len)
- return delta;
- delta += extra;
- }
- else
- {
- unsigned int ptr_size, width, extra = ent->add_augmentation_size;
- if (offset <= 12 || extra == 0)
- return delta;
- ptr_size = (get_elf_backend_data (sec->owner)
- ->elf_backend_eh_frame_address_size (sec->owner, sec));
- width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
- if (offset <= 8 + 2 * width)
- return delta;
- delta += extra;
- }
- return delta;
- }
- /* Adjust a global symbol defined in .eh_frame, so that it stays
- relative to its original CIE/FDE. It is assumed that a symbol
- defined at the beginning of a CIE/FDE belongs to that CIE/FDE
- rather than marking the end of the previous CIE/FDE. This matters
- when a CIE is merged with a previous CIE, since the symbol is
- moved to the merged CIE. */
- bool
- _bfd_elf_adjust_eh_frame_global_symbol (struct elf_link_hash_entry *h,
- void *arg ATTRIBUTE_UNUSED)
- {
- asection *sym_sec;
- bfd_signed_vma delta;
- if (h->root.type != bfd_link_hash_defined
- && h->root.type != bfd_link_hash_defweak)
- return true;
- sym_sec = h->root.u.def.section;
- if (sym_sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME
- || elf_section_data (sym_sec)->sec_info == NULL)
- return true;
- delta = offset_adjust (h->root.u.def.value, sym_sec);
- h->root.u.def.value += delta;
- return true;
- }
- /* The same for all local symbols defined in .eh_frame. Returns true
- if any symbol was changed. */
- static int
- adjust_eh_frame_local_symbols (const asection *sec,
- struct elf_reloc_cookie *cookie)
- {
- int adjusted = 0;
- if (cookie->locsymcount > 1)
- {
- unsigned int shndx = elf_section_data (sec)->this_idx;
- Elf_Internal_Sym *end_sym = cookie->locsyms + cookie->locsymcount;
- Elf_Internal_Sym *sym;
- for (sym = cookie->locsyms + 1; sym < end_sym; ++sym)
- if (sym->st_info <= ELF_ST_INFO (STB_LOCAL, STT_OBJECT)
- && sym->st_shndx == shndx)
- {
- bfd_signed_vma delta = offset_adjust (sym->st_value, sec);
- if (delta != 0)
- {
- adjusted = 1;
- sym->st_value += delta;
- }
- }
- }
- return adjusted;
- }
- /* This function is called for each input file before the .eh_frame
- section is relocated. It discards duplicate CIEs and FDEs for discarded
- functions. The function returns TRUE iff any entries have been
- deleted. */
- bool
- _bfd_elf_discard_section_eh_frame
- (bfd *abfd, struct bfd_link_info *info, asection *sec,
- bool (*reloc_symbol_deleted_p) (bfd_vma, void *),
- struct elf_reloc_cookie *cookie)
- {
- struct eh_cie_fde *ent;
- struct eh_frame_sec_info *sec_info;
- struct eh_frame_hdr_info *hdr_info;
- unsigned int ptr_size, offset, eh_alignment;
- int changed;
- if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME)
- return false;
- sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info;
- if (sec_info == NULL)
- return false;
- ptr_size = (get_elf_backend_data (sec->owner)
- ->elf_backend_eh_frame_address_size (sec->owner, sec));
- hdr_info = &elf_hash_table (info)->eh_info;
- for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent)
- if (ent->size == 4)
- /* There should only be one zero terminator, on the last input
- file supplying .eh_frame (crtend.o). Remove any others. */
- ent->removed = sec->map_head.s != NULL;
- else if (!ent->cie && ent->u.fde.cie_inf != NULL)
- {
- bool keep;
- if ((sec->flags & SEC_LINKER_CREATED) != 0 && cookie->rels == NULL)
- {
- unsigned int width
- = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
- bfd_vma value
- = read_value (abfd, sec->contents + ent->offset + 8 + width,
- width, get_DW_EH_PE_signed (ent->fde_encoding));
- keep = value != 0;
- }
- else
- {
- cookie->rel = cookie->rels + ent->reloc_index;
- /* FIXME: octets_per_byte. */
- BFD_ASSERT (cookie->rel < cookie->relend
- && cookie->rel->r_offset == ent->offset + 8);
- keep = !(*reloc_symbol_deleted_p) (ent->offset + 8, cookie);
- }
- if (keep)
- {
- if (bfd_link_pic (info)
- && (((ent->fde_encoding & 0x70) == DW_EH_PE_absptr
- && ent->make_relative == 0)
- || (ent->fde_encoding & 0x70) == DW_EH_PE_aligned))
- {
- static int num_warnings_issued = 0;
- /* If a shared library uses absolute pointers
- which we cannot turn into PC relative,
- don't create the binary search table,
- since it is affected by runtime relocations. */
- hdr_info->u.dwarf.table = false;
- /* Only warn if --eh-frame-hdr was specified. */
- if (info->eh_frame_hdr_type != 0)
- {
- if (num_warnings_issued < 10)
- {
- _bfd_error_handler
- /* xgettext:c-format */
- (_("FDE encoding in %pB(%pA) prevents .eh_frame_hdr"
- " table being created"), abfd, sec);
- num_warnings_issued ++;
- }
- else if (num_warnings_issued == 10)
- {
- _bfd_error_handler
- (_("further warnings about FDE encoding preventing .eh_frame_hdr generation dropped"));
- num_warnings_issued ++;
- }
- }
- }
- ent->removed = 0;
- hdr_info->u.dwarf.fde_count++;
- ent->u.fde.cie_inf = find_merged_cie (abfd, info, sec, hdr_info,
- cookie, ent->u.fde.cie_inf);
- }
- }
- free (sec_info->cies);
- sec_info->cies = NULL;
- /* It may be that some .eh_frame input section has greater alignment
- than other .eh_frame sections. In that case we run the risk of
- padding with zeros before that section, which would be seen as a
- zero terminator. Alignment padding must be added *inside* the
- last FDE instead. For other FDEs we align according to their
- encoding, in order to align FDE address range entries naturally. */
- offset = 0;
- changed = 0;
- for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent)
- if (!ent->removed)
- {
- eh_alignment = 4;
- if (ent->size == 4)
- ;
- else if (ent->cie)
- {
- if (ent->u.cie.per_encoding_aligned8)
- eh_alignment = 8;
- }
- else
- {
- eh_alignment = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
- if (eh_alignment < 4)
- eh_alignment = 4;
- }
- offset = (offset + eh_alignment - 1) & -eh_alignment;
- ent->new_offset = offset;
- if (ent->new_offset != ent->offset)
- changed = 1;
- offset += size_of_output_cie_fde (ent);
- }
- eh_alignment = 4;
- offset = (offset + eh_alignment - 1) & -eh_alignment;
- sec->rawsize = sec->size;
- sec->size = offset;
- if (sec->size != sec->rawsize)
- changed = 1;
- if (changed && adjust_eh_frame_local_symbols (sec, cookie))
- {
- Elf_Internal_Shdr *symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
- symtab_hdr->contents = (unsigned char *) cookie->locsyms;
- }
- return changed;
- }
- /* This function is called for .eh_frame_hdr section after
- _bfd_elf_discard_section_eh_frame has been called on all .eh_frame
- input sections. It finalizes the size of .eh_frame_hdr section. */
- bool
- _bfd_elf_discard_section_eh_frame_hdr (struct bfd_link_info *info)
- {
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- asection *sec;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- if (!hdr_info->frame_hdr_is_compact && hdr_info->u.dwarf.cies != NULL)
- {
- htab_delete (hdr_info->u.dwarf.cies);
- hdr_info->u.dwarf.cies = NULL;
- }
- sec = hdr_info->hdr_sec;
- if (sec == NULL)
- return false;
- if (info->eh_frame_hdr_type == COMPACT_EH_HDR)
- {
- /* For compact frames we only add the header. The actual table comes
- from the .eh_frame_entry sections. */
- sec->size = 8;
- }
- else
- {
- sec->size = EH_FRAME_HDR_SIZE;
- if (hdr_info->u.dwarf.table)
- sec->size += 4 + hdr_info->u.dwarf.fde_count * 8;
- }
- return true;
- }
- /* Return true if there is at least one non-empty .eh_frame section in
- input files. Can only be called after ld has mapped input to
- output sections, and before sections are stripped. */
- bool
- _bfd_elf_eh_frame_present (struct bfd_link_info *info)
- {
- asection *eh = bfd_get_section_by_name (info->output_bfd, ".eh_frame");
- if (eh == NULL)
- return false;
- /* Count only sections which have at least a single CIE or FDE.
- There cannot be any CIE or FDE <= 8 bytes. */
- for (eh = eh->map_head.s; eh != NULL; eh = eh->map_head.s)
- if (eh->size > 8)
- return true;
- return false;
- }
- /* Return true if there is at least one .eh_frame_entry section in
- input files. */
- bool
- _bfd_elf_eh_frame_entry_present (struct bfd_link_info *info)
- {
- asection *o;
- bfd *abfd;
- for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
- {
- for (o = abfd->sections; o; o = o->next)
- {
- const char *name = bfd_section_name (o);
- if (strcmp (name, ".eh_frame_entry")
- && !bfd_is_abs_section (o->output_section))
- return true;
- }
- }
- return false;
- }
- /* This function is called from size_dynamic_sections.
- It needs to decide whether .eh_frame_hdr should be output or not,
- because when the dynamic symbol table has been sized it is too late
- to strip sections. */
- bool
- _bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info)
- {
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- struct bfd_link_hash_entry *bh = NULL;
- struct elf_link_hash_entry *h;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- if (hdr_info->hdr_sec == NULL)
- return true;
- if (bfd_is_abs_section (hdr_info->hdr_sec->output_section)
- || info->eh_frame_hdr_type == 0
- || (info->eh_frame_hdr_type == DWARF2_EH_HDR
- && !_bfd_elf_eh_frame_present (info))
- || (info->eh_frame_hdr_type == COMPACT_EH_HDR
- && !_bfd_elf_eh_frame_entry_present (info)))
- {
- hdr_info->hdr_sec->flags |= SEC_EXCLUDE;
- hdr_info->hdr_sec = NULL;
- return true;
- }
- /* Add a hidden symbol so that systems without access to PHDRs can
- find the table. */
- if (! (_bfd_generic_link_add_one_symbol
- (info, info->output_bfd, "__GNU_EH_FRAME_HDR", BSF_LOCAL,
- hdr_info->hdr_sec, 0, NULL, false, false, &bh)))
- return false;
- h = (struct elf_link_hash_entry *) bh;
- h->def_regular = 1;
- h->other = STV_HIDDEN;
- get_elf_backend_data
- (info->output_bfd)->elf_backend_hide_symbol (info, h, true);
- if (!hdr_info->frame_hdr_is_compact)
- hdr_info->u.dwarf.table = true;
- return true;
- }
- /* Adjust an address in the .eh_frame section. Given OFFSET within
- SEC, this returns the new offset in the adjusted .eh_frame section,
- or -1 if the address refers to a CIE/FDE which has been removed
- or to offset with dynamic relocation which is no longer needed. */
- bfd_vma
- _bfd_elf_eh_frame_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED,
- struct bfd_link_info *info ATTRIBUTE_UNUSED,
- asection *sec,
- bfd_vma offset)
- {
- struct eh_frame_sec_info *sec_info;
- unsigned int lo, hi, mid;
- if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME)
- return offset;
- sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info;
- if (offset >= sec->rawsize)
- return offset - sec->rawsize + sec->size;
- lo = 0;
- hi = sec_info->count;
- mid = 0;
- while (lo < hi)
- {
- mid = (lo + hi) / 2;
- if (offset < sec_info->entry[mid].offset)
- hi = mid;
- else if (offset
- >= sec_info->entry[mid].offset + sec_info->entry[mid].size)
- lo = mid + 1;
- else
- break;
- }
- BFD_ASSERT (lo < hi);
- /* FDE or CIE was removed. */
- if (sec_info->entry[mid].removed)
- return (bfd_vma) -1;
- /* If converting personality pointers to DW_EH_PE_pcrel, there will be
- no need for run-time relocation against the personality field. */
- if (sec_info->entry[mid].cie
- && sec_info->entry[mid].u.cie.make_per_encoding_relative
- && offset == (sec_info->entry[mid].offset + 8
- + sec_info->entry[mid].u.cie.personality_offset))
- return (bfd_vma) -2;
- /* If converting to DW_EH_PE_pcrel, there will be no need for run-time
- relocation against FDE's initial_location field. */
- if (!sec_info->entry[mid].cie
- && sec_info->entry[mid].make_relative
- && offset == sec_info->entry[mid].offset + 8)
- return (bfd_vma) -2;
- /* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need
- for run-time relocation against LSDA field. */
- if (!sec_info->entry[mid].cie
- && sec_info->entry[mid].u.fde.cie_inf->u.cie.make_lsda_relative
- && offset == (sec_info->entry[mid].offset + 8
- + sec_info->entry[mid].lsda_offset))
- return (bfd_vma) -2;
- /* If converting to DW_EH_PE_pcrel, there will be no need for run-time
- relocation against DW_CFA_set_loc's arguments. */
- if (sec_info->entry[mid].set_loc
- && sec_info->entry[mid].make_relative
- && (offset >= sec_info->entry[mid].offset + 8
- + sec_info->entry[mid].set_loc[1]))
- {
- unsigned int cnt;
- for (cnt = 1; cnt <= sec_info->entry[mid].set_loc[0]; cnt++)
- if (offset == sec_info->entry[mid].offset + 8
- + sec_info->entry[mid].set_loc[cnt])
- return (bfd_vma) -2;
- }
- /* Any new augmentation bytes go before the first relocation. */
- return (offset + sec_info->entry[mid].new_offset
- - sec_info->entry[mid].offset
- + extra_augmentation_string_bytes (sec_info->entry + mid)
- + extra_augmentation_data_bytes (sec_info->entry + mid));
- }
- /* Write out .eh_frame_entry section. Add CANTUNWIND terminator if needed.
- Also check that the contents look sane. */
- bool
- _bfd_elf_write_section_eh_frame_entry (bfd *abfd, struct bfd_link_info *info,
- asection *sec, bfd_byte *contents)
- {
- const struct elf_backend_data *bed;
- bfd_byte cantunwind[8];
- bfd_vma addr;
- bfd_vma last_addr;
- bfd_vma offset;
- asection *text_sec = (asection *) elf_section_data (sec)->sec_info;
- if (!sec->rawsize)
- sec->rawsize = sec->size;
- BFD_ASSERT (sec->sec_info_type == SEC_INFO_TYPE_EH_FRAME_ENTRY);
- /* Check to make sure that the text section corresponding to this eh_frame_entry
- section has not been excluded. In particular, mips16 stub entries will be
- excluded outside of the normal process. */
- if (sec->flags & SEC_EXCLUDE
- || text_sec->flags & SEC_EXCLUDE)
- return true;
- if (!bfd_set_section_contents (abfd, sec->output_section, contents,
- sec->output_offset, sec->rawsize))
- return false;
- last_addr = bfd_get_signed_32 (abfd, contents);
- /* Check that all the entries are in order. */
- for (offset = 8; offset < sec->rawsize; offset += 8)
- {
- addr = bfd_get_signed_32 (abfd, contents + offset) + offset;
- if (addr <= last_addr)
- {
- /* xgettext:c-format */
- _bfd_error_handler (_("%pB: %pA not in order"), sec->owner, sec);
- return false;
- }
- last_addr = addr;
- }
- addr = text_sec->output_section->vma + text_sec->output_offset
- + text_sec->size;
- addr &= ~1;
- addr -= (sec->output_section->vma + sec->output_offset + sec->rawsize);
- if (addr & 1)
- {
- /* xgettext:c-format */
- _bfd_error_handler (_("%pB: %pA invalid input section size"),
- sec->owner, sec);
- bfd_set_error (bfd_error_bad_value);
- return false;
- }
- if (last_addr >= addr + sec->rawsize)
- {
- /* xgettext:c-format */
- _bfd_error_handler (_("%pB: %pA points past end of text section"),
- sec->owner, sec);
- bfd_set_error (bfd_error_bad_value);
- return false;
- }
- if (sec->size == sec->rawsize)
- return true;
- bed = get_elf_backend_data (abfd);
- BFD_ASSERT (sec->size == sec->rawsize + 8);
- BFD_ASSERT ((addr & 1) == 0);
- BFD_ASSERT (bed->cant_unwind_opcode);
- bfd_put_32 (abfd, addr, cantunwind);
- bfd_put_32 (abfd, (*bed->cant_unwind_opcode) (info), cantunwind + 4);
- return bfd_set_section_contents (abfd, sec->output_section, cantunwind,
- sec->output_offset + sec->rawsize, 8);
- }
- /* Write out .eh_frame section. This is called with the relocated
- contents. */
- bool
- _bfd_elf_write_section_eh_frame (bfd *abfd,
- struct bfd_link_info *info,
- asection *sec,
- bfd_byte *contents)
- {
- struct eh_frame_sec_info *sec_info;
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- unsigned int ptr_size;
- struct eh_cie_fde *ent, *last_ent;
- if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME)
- /* FIXME: octets_per_byte. */
- return bfd_set_section_contents (abfd, sec->output_section, contents,
- sec->output_offset, sec->size);
- ptr_size = (get_elf_backend_data (abfd)
- ->elf_backend_eh_frame_address_size (abfd, sec));
- BFD_ASSERT (ptr_size != 0);
- sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- if (hdr_info->u.dwarf.table && hdr_info->u.dwarf.array == NULL)
- {
- hdr_info->frame_hdr_is_compact = false;
- hdr_info->u.dwarf.array = (struct eh_frame_array_ent *)
- bfd_malloc (hdr_info->u.dwarf.fde_count
- * sizeof (*hdr_info->u.dwarf.array));
- }
- if (hdr_info->u.dwarf.array == NULL)
- hdr_info = NULL;
- /* The new offsets can be bigger or smaller than the original offsets.
- We therefore need to make two passes over the section: one backward
- pass to move entries up and one forward pass to move entries down.
- The two passes won't interfere with each other because entries are
- not reordered */
- for (ent = sec_info->entry + sec_info->count; ent-- != sec_info->entry;)
- if (!ent->removed && ent->new_offset > ent->offset)
- memmove (contents + ent->new_offset, contents + ent->offset, ent->size);
- for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent)
- if (!ent->removed && ent->new_offset < ent->offset)
- memmove (contents + ent->new_offset, contents + ent->offset, ent->size);
- last_ent = sec_info->entry + sec_info->count;
- for (ent = sec_info->entry; ent < last_ent; ++ent)
- {
- unsigned char *buf, *end;
- unsigned int new_size;
- if (ent->removed)
- continue;
- if (ent->size == 4)
- {
- /* Any terminating FDE must be at the end of the section. */
- BFD_ASSERT (ent == last_ent - 1);
- continue;
- }
- buf = contents + ent->new_offset;
- end = buf + ent->size;
- new_size = next_cie_fde_offset (ent, last_ent, sec) - ent->new_offset;
- /* Update the size. It may be shrinked. */
- bfd_put_32 (abfd, new_size - 4, buf);
- /* Filling the extra bytes with DW_CFA_nops. */
- if (new_size != ent->size)
- memset (end, 0, new_size - ent->size);
- if (ent->cie)
- {
- /* CIE */
- if (ent->make_relative
- || ent->u.cie.make_lsda_relative
- || ent->u.cie.per_encoding_relative)
- {
- char *aug;
- unsigned int version, action, extra_string, extra_data;
- unsigned int per_width, per_encoding;
- /* Need to find 'R' or 'L' augmentation's argument and modify
- DW_EH_PE_* value. */
- action = ((ent->make_relative ? 1 : 0)
- | (ent->u.cie.make_lsda_relative ? 2 : 0)
- | (ent->u.cie.per_encoding_relative ? 4 : 0));
- extra_string = extra_augmentation_string_bytes (ent);
- extra_data = extra_augmentation_data_bytes (ent);
- /* Skip length, id. */
- buf += 8;
- version = *buf++;
- aug = (char *) buf;
- buf += strlen (aug) + 1;
- skip_leb128 (&buf, end);
- skip_leb128 (&buf, end);
- if (version == 1)
- skip_bytes (&buf, end, 1);
- else
- skip_leb128 (&buf, end);
- if (*aug == 'z')
- {
- /* The uleb128 will always be a single byte for the kind
- of augmentation strings that we're prepared to handle. */
- *buf++ += extra_data;
- aug++;
- }
- /* Make room for the new augmentation string and data bytes. */
- memmove (buf + extra_string + extra_data, buf, end - buf);
- memmove (aug + extra_string, aug, buf - (bfd_byte *) aug);
- buf += extra_string;
- end += extra_string + extra_data;
- if (ent->add_augmentation_size)
- {
- *aug++ = 'z';
- *buf++ = extra_data - 1;
- }
- if (ent->u.cie.add_fde_encoding)
- {
- BFD_ASSERT (action & 1);
- *aug++ = 'R';
- *buf++ = make_pc_relative (DW_EH_PE_absptr, ptr_size);
- action &= ~1;
- }
- while (action)
- switch (*aug++)
- {
- case 'L':
- if (action & 2)
- {
- BFD_ASSERT (*buf == ent->lsda_encoding);
- *buf = make_pc_relative (*buf, ptr_size);
- action &= ~2;
- }
- buf++;
- break;
- case 'P':
- if (ent->u.cie.make_per_encoding_relative)
- *buf = make_pc_relative (*buf, ptr_size);
- per_encoding = *buf++;
- per_width = get_DW_EH_PE_width (per_encoding, ptr_size);
- BFD_ASSERT (per_width != 0);
- BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel)
- == ent->u.cie.per_encoding_relative);
- if ((per_encoding & 0x70) == DW_EH_PE_aligned)
- buf = (contents
- + ((buf - contents + per_width - 1)
- & ~((bfd_size_type) per_width - 1)));
- if (action & 4)
- {
- bfd_vma val;
- val = read_value (abfd, buf, per_width,
- get_DW_EH_PE_signed (per_encoding));
- if (ent->u.cie.make_per_encoding_relative)
- val -= (sec->output_section->vma
- + sec->output_offset
- + (buf - contents));
- else
- {
- val += (bfd_vma) ent->offset - ent->new_offset;
- val -= extra_string + extra_data;
- }
- write_value (abfd, buf, val, per_width);
- action &= ~4;
- }
- buf += per_width;
- break;
- case 'R':
- if (action & 1)
- {
- BFD_ASSERT (*buf == ent->fde_encoding);
- *buf = make_pc_relative (*buf, ptr_size);
- action &= ~1;
- }
- buf++;
- break;
- case 'S':
- break;
- default:
- BFD_FAIL ();
- }
- }
- }
- else
- {
- /* FDE */
- bfd_vma value, address;
- unsigned int width;
- bfd_byte *start;
- struct eh_cie_fde *cie;
- /* Skip length. */
- cie = ent->u.fde.cie_inf;
- buf += 4;
- value = ((ent->new_offset + sec->output_offset + 4)
- - (cie->new_offset + cie->u.cie.u.sec->output_offset));
- bfd_put_32 (abfd, value, buf);
- if (bfd_link_relocatable (info))
- continue;
- buf += 4;
- width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
- value = read_value (abfd, buf, width,
- get_DW_EH_PE_signed (ent->fde_encoding));
- address = value;
- if (value)
- {
- switch (ent->fde_encoding & 0x70)
- {
- case DW_EH_PE_textrel:
- BFD_ASSERT (hdr_info == NULL);
- break;
- case DW_EH_PE_datarel:
- {
- switch (abfd->arch_info->arch)
- {
- case bfd_arch_ia64:
- BFD_ASSERT (elf_gp (abfd) != 0);
- address += elf_gp (abfd);
- break;
- default:
- _bfd_error_handler
- (_("DW_EH_PE_datarel unspecified"
- " for this architecture"));
- /* Fall thru */
- case bfd_arch_frv:
- case bfd_arch_i386:
- case bfd_arch_nios2:
- BFD_ASSERT (htab->hgot != NULL
- && ((htab->hgot->root.type
- == bfd_link_hash_defined)
- || (htab->hgot->root.type
- == bfd_link_hash_defweak)));
- address
- += (htab->hgot->root.u.def.value
- + htab->hgot->root.u.def.section->output_offset
- + (htab->hgot->root.u.def.section->output_section
- ->vma));
- break;
- }
- }
- break;
- case DW_EH_PE_pcrel:
- value += (bfd_vma) ent->offset - ent->new_offset;
- address += (sec->output_section->vma
- + sec->output_offset
- + ent->offset + 8);
- break;
- }
- if (ent->make_relative)
- value -= (sec->output_section->vma
- + sec->output_offset
- + ent->new_offset + 8);
- write_value (abfd, buf, value, width);
- }
- start = buf;
- if (hdr_info)
- {
- /* The address calculation may overflow, giving us a
- value greater than 4G on a 32-bit target when
- dwarf_vma is 64-bit. */
- if (sizeof (address) > 4 && ptr_size == 4)
- address &= 0xffffffff;
- hdr_info->u.dwarf.array[hdr_info->array_count].initial_loc
- = address;
- hdr_info->u.dwarf.array[hdr_info->array_count].range
- = read_value (abfd, buf + width, width, false);
- hdr_info->u.dwarf.array[hdr_info->array_count++].fde
- = (sec->output_section->vma
- + sec->output_offset
- + ent->new_offset);
- }
- if ((ent->lsda_encoding & 0x70) == DW_EH_PE_pcrel
- || cie->u.cie.make_lsda_relative)
- {
- buf += ent->lsda_offset;
- width = get_DW_EH_PE_width (ent->lsda_encoding, ptr_size);
- value = read_value (abfd, buf, width,
- get_DW_EH_PE_signed (ent->lsda_encoding));
- if (value)
- {
- if ((ent->lsda_encoding & 0x70) == DW_EH_PE_pcrel)
- value += (bfd_vma) ent->offset - ent->new_offset;
- else if (cie->u.cie.make_lsda_relative)
- value -= (sec->output_section->vma
- + sec->output_offset
- + ent->new_offset + 8 + ent->lsda_offset);
- write_value (abfd, buf, value, width);
- }
- }
- else if (ent->add_augmentation_size)
- {
- /* Skip the PC and length and insert a zero byte for the
- augmentation size. */
- buf += width * 2;
- memmove (buf + 1, buf, end - buf);
- *buf = 0;
- }
- if (ent->set_loc)
- {
- /* Adjust DW_CFA_set_loc. */
- unsigned int cnt;
- bfd_vma new_offset;
- width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
- new_offset = ent->new_offset + 8
- + extra_augmentation_string_bytes (ent)
- + extra_augmentation_data_bytes (ent);
- for (cnt = 1; cnt <= ent->set_loc[0]; cnt++)
- {
- buf = start + ent->set_loc[cnt];
- value = read_value (abfd, buf, width,
- get_DW_EH_PE_signed (ent->fde_encoding));
- if (!value)
- continue;
- if ((ent->fde_encoding & 0x70) == DW_EH_PE_pcrel)
- value += (bfd_vma) ent->offset + 8 - new_offset;
- if (ent->make_relative)
- value -= (sec->output_section->vma
- + sec->output_offset
- + new_offset + ent->set_loc[cnt]);
- write_value (abfd, buf, value, width);
- }
- }
- }
- }
- /* FIXME: octets_per_byte. */
- return bfd_set_section_contents (abfd, sec->output_section,
- contents, (file_ptr) sec->output_offset,
- sec->size);
- }
- /* Helper function used to sort .eh_frame_hdr search table by increasing
- VMA of FDE initial location. */
- static int
- vma_compare (const void *a, const void *b)
- {
- const struct eh_frame_array_ent *p = (const struct eh_frame_array_ent *) a;
- const struct eh_frame_array_ent *q = (const struct eh_frame_array_ent *) b;
- if (p->initial_loc > q->initial_loc)
- return 1;
- if (p->initial_loc < q->initial_loc)
- return -1;
- if (p->range > q->range)
- return 1;
- if (p->range < q->range)
- return -1;
- return 0;
- }
- /* Reorder .eh_frame_entry sections to match the associated text sections.
- This routine is called during the final linking step, just before writing
- the contents. At this stage, sections in the eh_frame_hdr_info are already
- sorted in order of increasing text section address and so we simply need
- to make the .eh_frame_entrys follow that same order. Note that it is
- invalid for a linker script to try to force a particular order of
- .eh_frame_entry sections. */
- bool
- _bfd_elf_fixup_eh_frame_hdr (struct bfd_link_info *info)
- {
- asection *sec = NULL;
- asection *osec;
- struct eh_frame_hdr_info *hdr_info;
- unsigned int i;
- bfd_vma offset;
- struct bfd_link_order *p;
- hdr_info = &elf_hash_table (info)->eh_info;
- if (hdr_info->hdr_sec == NULL
- || info->eh_frame_hdr_type != COMPACT_EH_HDR
- || hdr_info->array_count == 0)
- return true;
- /* Change section output offsets to be in text section order. */
- offset = 8;
- osec = hdr_info->u.compact.entries[0]->output_section;
- for (i = 0; i < hdr_info->array_count; i++)
- {
- sec = hdr_info->u.compact.entries[i];
- if (sec->output_section != osec)
- {
- _bfd_error_handler
- (_("invalid output section for .eh_frame_entry: %pA"),
- sec->output_section);
- return false;
- }
- sec->output_offset = offset;
- offset += sec->size;
- }
- /* Fix the link_order to match. */
- for (p = sec->output_section->map_head.link_order; p != NULL; p = p->next)
- {
- if (p->type != bfd_indirect_link_order)
- abort();
- p->offset = p->u.indirect.section->output_offset;
- if (p->next != NULL)
- i--;
- }
- if (i != 0)
- {
- _bfd_error_handler
- (_("invalid contents in %pA section"), osec);
- return false;
- }
- return true;
- }
- /* The .eh_frame_hdr format for Compact EH frames:
- ubyte version (2)
- ubyte eh_ref_enc (DW_EH_PE_* encoding of typinfo references)
- uint32_t count (Number of entries in table)
- [array from .eh_frame_entry sections] */
- static bool
- write_compact_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info)
- {
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- asection *sec;
- const struct elf_backend_data *bed;
- bfd_vma count;
- bfd_byte contents[8];
- unsigned int i;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- sec = hdr_info->hdr_sec;
- if (sec->size != 8)
- abort();
- for (i = 0; i < sizeof (contents); i++)
- contents[i] = 0;
- contents[0] = COMPACT_EH_HDR;
- bed = get_elf_backend_data (abfd);
- BFD_ASSERT (bed->compact_eh_encoding);
- contents[1] = (*bed->compact_eh_encoding) (info);
- count = (sec->output_section->size - 8) / 8;
- bfd_put_32 (abfd, count, contents + 4);
- return bfd_set_section_contents (abfd, sec->output_section, contents,
- (file_ptr) sec->output_offset, sec->size);
- }
- /* The .eh_frame_hdr format for DWARF frames:
- ubyte version (currently 1)
- ubyte eh_frame_ptr_enc (DW_EH_PE_* encoding of pointer to start of
- .eh_frame section)
- ubyte fde_count_enc (DW_EH_PE_* encoding of total FDE count
- number (or DW_EH_PE_omit if there is no
- binary search table computed))
- ubyte table_enc (DW_EH_PE_* encoding of binary search table,
- or DW_EH_PE_omit if not present.
- DW_EH_PE_datarel is using address of
- .eh_frame_hdr section start as base)
- [encoded] eh_frame_ptr (pointer to start of .eh_frame section)
- optionally followed by:
- [encoded] fde_count (total number of FDEs in .eh_frame section)
- fde_count x [encoded] initial_loc, fde
- (array of encoded pairs containing
- FDE initial_location field and FDE address,
- sorted by increasing initial_loc). */
- static bool
- write_dwarf_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info)
- {
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- asection *sec;
- bool retval = true;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- sec = hdr_info->hdr_sec;
- bfd_byte *contents;
- asection *eh_frame_sec;
- bfd_size_type size;
- bfd_vma encoded_eh_frame;
- size = EH_FRAME_HDR_SIZE;
- if (hdr_info->u.dwarf.array
- && hdr_info->array_count == hdr_info->u.dwarf.fde_count)
- size += 4 + hdr_info->u.dwarf.fde_count * 8;
- contents = (bfd_byte *) bfd_malloc (size);
- if (contents == NULL)
- return false;
- eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame");
- if (eh_frame_sec == NULL)
- {
- free (contents);
- return false;
- }
- memset (contents, 0, EH_FRAME_HDR_SIZE);
- /* Version. */
- contents[0] = 1;
- /* .eh_frame offset. */
- contents[1] = get_elf_backend_data (abfd)->elf_backend_encode_eh_address
- (abfd, info, eh_frame_sec, 0, sec, 4, &encoded_eh_frame);
- if (hdr_info->u.dwarf.array
- && hdr_info->array_count == hdr_info->u.dwarf.fde_count)
- {
- /* FDE count encoding. */
- contents[2] = DW_EH_PE_udata4;
- /* Search table encoding. */
- contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4;
- }
- else
- {
- contents[2] = DW_EH_PE_omit;
- contents[3] = DW_EH_PE_omit;
- }
- bfd_put_32 (abfd, encoded_eh_frame, contents + 4);
- if (contents[2] != DW_EH_PE_omit)
- {
- unsigned int i;
- bool overlap, overflow;
- bfd_put_32 (abfd, hdr_info->u.dwarf.fde_count,
- contents + EH_FRAME_HDR_SIZE);
- qsort (hdr_info->u.dwarf.array, hdr_info->u.dwarf.fde_count,
- sizeof (*hdr_info->u.dwarf.array), vma_compare);
- overlap = false;
- overflow = false;
- for (i = 0; i < hdr_info->u.dwarf.fde_count; i++)
- {
- bfd_vma val;
- val = hdr_info->u.dwarf.array[i].initial_loc
- - sec->output_section->vma;
- val = ((val & 0xffffffff) ^ 0x80000000) - 0x80000000;
- if (elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64
- && (hdr_info->u.dwarf.array[i].initial_loc
- != sec->output_section->vma + val))
- overflow = true;
- bfd_put_32 (abfd, val, contents + EH_FRAME_HDR_SIZE + i * 8 + 4);
- val = hdr_info->u.dwarf.array[i].fde - sec->output_section->vma;
- val = ((val & 0xffffffff) ^ 0x80000000) - 0x80000000;
- if (elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64
- && (hdr_info->u.dwarf.array[i].fde
- != sec->output_section->vma + val))
- overflow = true;
- bfd_put_32 (abfd, val, contents + EH_FRAME_HDR_SIZE + i * 8 + 8);
- if (i != 0
- && (hdr_info->u.dwarf.array[i].initial_loc
- < (hdr_info->u.dwarf.array[i - 1].initial_loc
- + hdr_info->u.dwarf.array[i - 1].range)))
- overlap = true;
- }
- if (overflow)
- _bfd_error_handler (_(".eh_frame_hdr entry overflow"));
- if (overlap)
- _bfd_error_handler (_(".eh_frame_hdr refers to overlapping FDEs"));
- if (overflow || overlap)
- {
- bfd_set_error (bfd_error_bad_value);
- retval = false;
- }
- }
- /* FIXME: octets_per_byte. */
- if (!bfd_set_section_contents (abfd, sec->output_section, contents,
- (file_ptr) sec->output_offset,
- sec->size))
- retval = false;
- free (contents);
- free (hdr_info->u.dwarf.array);
- return retval;
- }
- /* Write out .eh_frame_hdr section. This must be called after
- _bfd_elf_write_section_eh_frame has been called on all input
- .eh_frame sections. */
- bool
- _bfd_elf_write_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info)
- {
- struct elf_link_hash_table *htab;
- struct eh_frame_hdr_info *hdr_info;
- asection *sec;
- htab = elf_hash_table (info);
- hdr_info = &htab->eh_info;
- sec = hdr_info->hdr_sec;
- if (info->eh_frame_hdr_type == 0 || sec == NULL)
- return true;
- if (info->eh_frame_hdr_type == COMPACT_EH_HDR)
- return write_compact_eh_frame_hdr (abfd, info);
- else
- return write_dwarf_eh_frame_hdr (abfd, info);
- }
- /* Return the width of FDE addresses. This is the default implementation. */
- unsigned int
- _bfd_elf_eh_frame_address_size (bfd *abfd, const asection *sec ATTRIBUTE_UNUSED)
- {
- return elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64 ? 8 : 4;
- }
- /* Decide whether we can use a PC-relative encoding within the given
- EH frame section. This is the default implementation. */
- bool
- _bfd_elf_can_make_relative (bfd *input_bfd ATTRIBUTE_UNUSED,
- struct bfd_link_info *info ATTRIBUTE_UNUSED,
- asection *eh_frame_section ATTRIBUTE_UNUSED)
- {
- return true;
- }
- /* Select an encoding for the given address. Preference is given to
- PC-relative addressing modes. */
- bfd_byte
- _bfd_elf_encode_eh_address (bfd *abfd ATTRIBUTE_UNUSED,
- struct bfd_link_info *info ATTRIBUTE_UNUSED,
- asection *osec, bfd_vma offset,
- asection *loc_sec, bfd_vma loc_offset,
- bfd_vma *encoded)
- {
- *encoded = osec->vma + offset -
- (loc_sec->output_section->vma + loc_sec->output_offset + loc_offset);
- return DW_EH_PE_pcrel | DW_EH_PE_sdata4;
- }
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