/* .eh_frame section optimization.
- Copyright (C) 2001-2015 Free Software Foundation, Inc.
+ Copyright (C) 2001-2017 Free Software Foundation, Inc.
Written by Jakub Jelinek <jakub@redhat.com>.
This file is part of BFD, the Binary File Descriptor library.
return size;
}
-/* Return the size that ENTRY will have in the output. ALIGNMENT is the
- required alignment of ENTRY in bytes. */
+/* Return the size that ENTRY will have in the output. */
static unsigned int
-size_of_output_cie_fde (struct eh_cie_fde *entry, unsigned int alignment)
+size_of_output_cie_fde (struct eh_cie_fde *entry)
{
if (entry->removed)
return 0;
return 4;
return (entry->size
+ extra_augmentation_string_bytes (entry)
- + extra_augmentation_data_bytes (entry)
- + alignment - 1) & -alignment;
+ + 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.
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')
{
{
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);
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 (info->shared
- && !info->relocatable
+ if (bfd_link_pic (info)
&& (get_elf_backend_data (abfd)
->elf_backend_can_make_relative_eh_frame
(abfd, info, sec)))
buf += initial_insn_length;
ENSURE_NO_RELOCS (buf);
- if (!info->relocatable)
+ if (!bfd_link_relocatable (info))
{
/* Keep info for merging cies. */
this_inf->u.cie.u.full_cie = cie;
REQUIRE (GET_RELOC (buf));
/* Chain together the FDEs for each section. */
- rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook, cookie);
+ 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)
&& read_value (abfd, buf - length, length, FALSE) == 0)
{
(*info->callbacks->minfo)
+ /* xgettext:c-format */
(_("discarding zero address range FDE in %B(%A).\n"),
abfd, sec);
this_inf->u.fde.cie_inf = NULL;
elf_section_data (sec)->sec_info = sec_info;
sec->sec_info_type = SEC_INFO_TYPE_EH_FRAME;
- if (!info->relocatable)
+ if (!bfd_link_relocatable (info))
{
/* Keep info for merging cies. */
sec_info->cies = local_cies;
free_no_table:
(*info->callbacks->einfo)
+ /* xgettext:c-format */
(_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"),
abfd, sec);
hdr_info->u.dwarf.table = FALSE;
}
if (per_binds_local
- && info->shared
- && !info->relocatable
+ && 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)))
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;
+ 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. */
+
+bfd_boolean
+_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)
+{
+ unsigned int shndx;
+ Elf_Internal_Sym *sym;
+ Elf_Internal_Sym *end_sym;
+ int adjusted = 0;
+
+ shndx = elf_section_data (sec)->this_idx;
+ end_sym = cookie->locsyms + cookie->locsymcount;
+ 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
struct eh_cie_fde *ent;
struct eh_frame_sec_info *sec_info;
struct eh_frame_hdr_info *hdr_info;
- unsigned int ptr_size, offset;
+ unsigned int ptr_size, offset, eh_alignment;
+ int changed;
if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME)
return FALSE;
}
if (keep)
{
- if (info->shared
+ 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;
- (*info->callbacks->einfo)
- (_("%P: FDE encoding in %B(%A) prevents .eh_frame_hdr"
- " table being created.\n"), abfd, sec);
+ if (num_warnings_issued < 10)
+ {
+ (*info->callbacks->einfo)
+ /* xgettext:c-format */
+ (_("%P: FDE encoding in %B(%A) prevents .eh_frame_hdr"
+ " table being created.\n"), abfd, sec);
+ num_warnings_issued ++;
+ }
+ else if (num_warnings_issued == 10)
+ {
+ (*info->callbacks->einfo)
+ (_("%P: Further warnings about FDE encoding preventing .eh_frame_hdr generation dropped.\n"));
+ num_warnings_issued ++;
+ }
}
ent->removed = 0;
hdr_info->u.dwarf.fde_count++;
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;
- offset += size_of_output_cie_fde (ent, ptr_size);
+ if (ent->new_offset != ent->offset)
+ changed = 1;
+ offset += size_of_output_cie_fde (ent);
}
+ /* Pad the last FDE out to the output section alignment if there are
+ following sections, in order to ensure no padding between this
+ section and the next. (Relies on the output section alignment
+ being the maximum of all input sections alignments, which is the
+ case unless someone is overriding alignment via scripts.) */
+ eh_alignment = 4;
+ if (sec->map_head.s != NULL
+ && (sec->map_head.s->size != 4
+ || sec->map_head.s->map_head.s != NULL))
+ eh_alignment = 1 << sec->output_section->alignment_power;
+ offset = (offset + eh_alignment - 1) & -eh_alignment;
sec->rawsize = sec->size;
sec->size = offset;
- return offset != sec->rawsize;
+ 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
addr = bfd_get_signed_32 (abfd, contents + offset) + offset;
if (addr <= last_addr)
{
- (*_bfd_error_handler) (_("%B: %s not in order"), sec->owner, sec->name);
+ /* xgettext:c-format */
+ _bfd_error_handler (_("%B: %A not in order"), sec->owner, sec);
return FALSE;
}
addr -= (sec->output_section->vma + sec->output_offset + sec->rawsize);
if (addr & 1)
{
- (*_bfd_error_handler) (_("%B: %s invalid input section size"),
- sec->owner, sec->name);
+ /* xgettext:c-format */
+ _bfd_error_handler (_("%B: %A invalid input section size"),
+ sec->owner, sec);
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
if (last_addr >= addr + sec->rawsize)
{
- (*_bfd_error_handler) (_("%B: %s points past end of text section"),
- sec->owner, sec->name);
+ /* xgettext:c-format */
+ _bfd_error_handler (_("%B: %A points past end of text section"),
+ sec->owner, sec);
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
struct elf_link_hash_table *htab;
struct eh_frame_hdr_info *hdr_info;
unsigned int ptr_size;
- struct eh_cie_fde *ent;
- bfd_size_type sec_size;
+ struct eh_cie_fde *ent, *last_ent;
if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME)
/* FIXME: octets_per_byte. */
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)
+ 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->size == 4)
{
/* Any terminating FDE must be at the end of the section. */
- BFD_ASSERT (ent == sec_info->entry + sec_info->count - 1);
+ BFD_ASSERT (ent == last_ent - 1);
continue;
}
buf = contents + ent->new_offset;
end = buf + ent->size;
- new_size = size_of_output_cie_fde (ent, ptr_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);
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 (info->relocatable)
+ if (bfd_link_relocatable (info))
continue;
buf += 4;
width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size);
}
}
- /* We don't align the section to its section alignment since the
- runtime library only expects all CIE/FDE records aligned at
- the pointer size. _bfd_elf_discard_section_eh_frame should
- have padded CIE/FDE records to multiple of pointer size with
- size_of_output_cie_fde. */
- sec_size = sec->size;
- if (sec_info->count != 0
- && sec_info->entry[sec_info->count - 1].size == 4)
- sec_size -= 4;
- if ((sec_size % ptr_size) != 0)
- abort ();
-
/* FIXME: octets_per_byte. */
return bfd_set_section_contents (abfd, sec->output_section,
contents, (file_ptr) sec->output_offset,
sec = hdr_info->u.compact.entries[i];
if (sec->output_section != osec)
{
- (*_bfd_error_handler)
- (_("Invalid output section for .eh_frame_entry: %s"),
- sec->output_section->name);
+ _bfd_error_handler
+ (_("Invalid output section for .eh_frame_entry: %A"),
+ sec->output_section);
return FALSE;
}
sec->output_offset = offset;
if (i != 0)
{
- (*_bfd_error_handler)
- (_("Invalid contents in %s section"), osec->name);
+ _bfd_error_handler
+ (_("Invalid contents in %A section"), osec);
return FALSE;
}
/* Return the width of FDE addresses. This is the default implementation. */
unsigned int
-_bfd_elf_eh_frame_address_size (bfd *abfd, asection *sec ATTRIBUTE_UNUSED)
+_bfd_elf_eh_frame_address_size (bfd *abfd, const asection *sec ATTRIBUTE_UNUSED)
{
return elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64 ? 8 : 4;
}
projects / deliverable / binutils-gdb.git / blobdiff