/* .eh_frame section optimization.
- Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
Written by Jakub Jelinek <jakub@redhat.com>.
This file is part of BFD, the Binary File Descriptor library.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+ Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
#include "bfd.h"
#include "sysdep.h"
+ alignment - 1) & -alignment;
}
+/* 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 bfd_boolean
+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 & 0x80 ? op & 0xc0 : op)
+ {
+ case DW_CFA_nop:
+ case DW_CFA_advance_loc:
+ case DW_CFA_restore:
+ /* 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_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:
+ /* 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)
+{
+ bfd_byte *last;
+
+ last = buf;
+ while (buf < end)
+ if (*buf == DW_CFA_nop)
+ buf++;
+ else
+ {
+ if (!skip_cfa_op (&buf, end, encoded_ptr_width))
+ return 0;
+ last = buf;
+ }
+ return last;
+}
+
/* 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
it (it would need to use 64-bit .eh_frame format anyway). */
REQUIRE (sec->size == (unsigned int) sec->size);
- ptr_size = (elf_elfheader (abfd)->e_ident[EI_CLASS]
- == ELFCLASS64) ? 8 : 4;
+ ptr_size = (get_elf_backend_data (abfd)
+ ->elf_backend_eh_frame_address_size (abfd, sec));
+ REQUIRE (ptr_size != 0);
+
buf = ehbuf;
last_cie = NULL;
last_cie_inf = NULL;
for (;;)
{
- unsigned char *aug;
- bfd_byte *start, *end;
+ char *aug;
+ bfd_byte *start, *end, *insns;
bfd_size_type length;
if (sec_info->count == sec_info->alloced)
on whether to output or discard last encountered CIE (if any). */
if ((bfd_size_type) (buf - ehbuf) == sec->size)
{
+ hdr.length = 0;
hdr.id = (unsigned int) -1;
end = buf;
}
/* Cannot handle unknown versions. */
REQUIRE (cie.version == 1 || cie.version == 3);
- REQUIRE (strlen (buf) < sizeof (cie.augmentation));
+ REQUIRE (strlen ((char *) buf) < sizeof (cie.augmentation));
- strcpy (cie.augmentation, buf);
- buf = strchr (buf, '\0') + 1;
+ strcpy (cie.augmentation, (char *) buf);
+ buf = (bfd_byte *) strchr ((char *) buf, '\0') + 1;
ENSURE_NO_RELOCS (buf);
if (buf[0] == 'e' && buf[1] == 'h')
{
ENSURE_NO_RELOCS (buf);
REQUIRE (get_DW_EH_PE_width (cie.fde_encoding, ptr_size));
break;
+ case 'S':
+ break;
case 'P':
{
int per_width;
if (cie.fde_encoding == DW_EH_PE_omit)
cie.fde_encoding = DW_EH_PE_absptr;
- initial_insn_length = cie.hdr.length - (buf - last_fde - 4);
+ initial_insn_length = end - buf;
if (initial_insn_length <= 50)
{
cie.initial_insn_length = initial_insn_length;
memcpy (cie.initial_instructions, buf, initial_insn_length);
}
+ insns = buf;
buf += initial_insn_length;
ENSURE_NO_RELOCS (buf);
last_cie = last_fde;
/* Skip the augmentation size, if present. */
if (cie.augmentation[0] == 'z')
- REQUIRE (skip_leb128 (&buf, end));
+ 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)
- this_inf->lsda_offset = buf - start;
+ {
+ 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;
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
+ including the padding. */
+ length = get_DW_EH_PE_width (cie.fde_encoding, ptr_size);
+ insns = skip_non_nops (insns, end, length);
+ if (insns != 0)
+ this_inf->size -= end - insns;
+
this_inf->fde_encoding = cie.fde_encoding;
this_inf->lsda_encoding = cie.lsda_encoding;
sec_info->count++;
/* This function is called from size_dynamic_sections.
It needs to decide whether .eh_frame_hdr should be output or not,
- because later on it is too late for calling _bfd_strip_section_from_output,
- since dynamic symbol table has been sized. */
+ because when the dynamic symbol table has been sized it is too late
+ to strip sections. */
bfd_boolean
_bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info)
if (abfd == NULL)
{
- _bfd_strip_section_from_output (info, hdr_info->hdr_sec);
+ hdr_info->hdr_sec->flags |= SEC_EXCLUDE;
hdr_info->hdr_sec = NULL;
return TRUE;
}
unsigned int ptr_size;
struct eh_cie_fde *ent;
- ptr_size = (elf_elfheader (sec->owner)->e_ident[EI_CLASS]
- == ELFCLASS64) ? 8 : 4;
-
if (sec->sec_info_type != ELF_INFO_TYPE_EH_FRAME)
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 = elf_section_data (sec)->sec_info;
htab = elf_hash_table (info);
hdr_info = &htab->eh_info;
|| ent->need_lsda_relative
|| ent->per_encoding_relative)
{
- unsigned char *aug;
+ char *aug;
unsigned int action, extra_string, extra_data;
unsigned int per_width, per_encoding;
/* Skip length, id and version. */
buf += 9;
- aug = buf;
- buf = strchr (buf, '\0') + 1;
+ aug = (char *) buf;
+ buf += strlen (aug) + 1;
skip_leb128 (&buf, end);
skip_leb128 (&buf, end);
skip_leb128 (&buf, end);
/* 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 - aug);
+ memmove (aug + extra_string, aug, buf - (bfd_byte *) aug);
buf += extra_string;
end += extra_string + extra_data;
}
buf++;
break;
+ case 'S':
+ break;
default:
BFD_FAIL ();
}
return retval;
}
+/* 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)
+{
+ 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. */