1831 lines
52 KiB
C
1831 lines
52 KiB
C
/* .eh_frame section optimization.
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Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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Free Software Foundation, Inc.
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Written by Jakub Jelinek <jakub@redhat.com>.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "sysdep.h"
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#include "bfd.h"
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#include "libbfd.h"
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#include "elf-bfd.h"
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#include "dwarf2.h"
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#define EH_FRAME_HDR_SIZE 8
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struct cie
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{
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unsigned int length;
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unsigned int hash;
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unsigned char version;
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unsigned char local_personality;
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char augmentation[20];
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bfd_vma code_align;
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bfd_signed_vma data_align;
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bfd_vma ra_column;
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bfd_vma augmentation_size;
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union {
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struct elf_link_hash_entry *h;
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bfd_vma val;
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unsigned int reloc_index;
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} personality;
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asection *output_sec;
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struct eh_cie_fde *cie_inf;
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unsigned char per_encoding;
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unsigned char lsda_encoding;
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unsigned char fde_encoding;
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unsigned char initial_insn_length;
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unsigned char can_make_lsda_relative;
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unsigned char initial_instructions[50];
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};
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/* If *ITER hasn't reached END yet, read the next byte into *RESULT and
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move onto the next byte. Return true on success. */
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static inline bfd_boolean
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read_byte (bfd_byte **iter, bfd_byte *end, unsigned char *result)
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{
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if (*iter >= end)
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return FALSE;
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*result = *((*iter)++);
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return TRUE;
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}
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/* Move *ITER over LENGTH bytes, or up to END, whichever is closer.
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Return true it was possible to move LENGTH bytes. */
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static inline bfd_boolean
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skip_bytes (bfd_byte **iter, bfd_byte *end, bfd_size_type length)
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{
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if ((bfd_size_type) (end - *iter) < length)
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{
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*iter = end;
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return FALSE;
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}
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*iter += length;
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return TRUE;
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}
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/* Move *ITER over an leb128, stopping at END. Return true if the end
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of the leb128 was found. */
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static bfd_boolean
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skip_leb128 (bfd_byte **iter, bfd_byte *end)
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{
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unsigned char byte;
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do
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if (!read_byte (iter, end, &byte))
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return FALSE;
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while (byte & 0x80);
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return TRUE;
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}
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/* Like skip_leb128, but treat the leb128 as an unsigned value and
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store it in *VALUE. */
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static bfd_boolean
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read_uleb128 (bfd_byte **iter, bfd_byte *end, bfd_vma *value)
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{
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bfd_byte *start, *p;
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start = *iter;
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if (!skip_leb128 (iter, end))
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return FALSE;
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p = *iter;
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*value = *--p;
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while (p > start)
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*value = (*value << 7) | (*--p & 0x7f);
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return TRUE;
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}
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/* Like read_uleb128, but for signed values. */
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static bfd_boolean
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read_sleb128 (bfd_byte **iter, bfd_byte *end, bfd_signed_vma *value)
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{
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bfd_byte *start, *p;
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start = *iter;
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if (!skip_leb128 (iter, end))
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return FALSE;
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p = *iter;
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*value = ((*--p & 0x7f) ^ 0x40) - 0x40;
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while (p > start)
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*value = (*value << 7) | (*--p & 0x7f);
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return TRUE;
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}
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/* Return 0 if either encoding is variable width, or not yet known to bfd. */
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static
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int get_DW_EH_PE_width (int encoding, int ptr_size)
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{
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/* DW_EH_PE_ values of 0x60 and 0x70 weren't defined at the time .eh_frame
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was added to bfd. */
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if ((encoding & 0x60) == 0x60)
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return 0;
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switch (encoding & 7)
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{
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case DW_EH_PE_udata2: return 2;
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case DW_EH_PE_udata4: return 4;
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case DW_EH_PE_udata8: return 8;
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case DW_EH_PE_absptr: return ptr_size;
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default:
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break;
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}
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return 0;
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}
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#define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0)
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/* Read a width sized value from memory. */
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static bfd_vma
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read_value (bfd *abfd, bfd_byte *buf, int width, int is_signed)
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{
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bfd_vma value;
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switch (width)
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{
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case 2:
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if (is_signed)
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value = bfd_get_signed_16 (abfd, buf);
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else
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value = bfd_get_16 (abfd, buf);
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break;
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case 4:
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if (is_signed)
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value = bfd_get_signed_32 (abfd, buf);
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else
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value = bfd_get_32 (abfd, buf);
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break;
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case 8:
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if (is_signed)
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value = bfd_get_signed_64 (abfd, buf);
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else
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value = bfd_get_64 (abfd, buf);
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break;
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default:
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BFD_FAIL ();
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return 0;
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}
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return value;
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}
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/* Store a width sized value to memory. */
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static void
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write_value (bfd *abfd, bfd_byte *buf, bfd_vma value, int width)
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{
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switch (width)
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{
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case 2: bfd_put_16 (abfd, value, buf); break;
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case 4: bfd_put_32 (abfd, value, buf); break;
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case 8: bfd_put_64 (abfd, value, buf); break;
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default: BFD_FAIL ();
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}
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}
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/* Return one if C1 and C2 CIEs can be merged. */
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static int
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cie_eq (const void *e1, const void *e2)
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{
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const struct cie *c1 = (const struct cie *) e1;
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const struct cie *c2 = (const struct cie *) e2;
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if (c1->hash == c2->hash
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&& c1->length == c2->length
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&& c1->version == c2->version
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&& c1->local_personality == c2->local_personality
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&& strcmp (c1->augmentation, c2->augmentation) == 0
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&& strcmp (c1->augmentation, "eh") != 0
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&& c1->code_align == c2->code_align
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&& c1->data_align == c2->data_align
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&& c1->ra_column == c2->ra_column
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&& c1->augmentation_size == c2->augmentation_size
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&& memcmp (&c1->personality, &c2->personality,
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sizeof (c1->personality)) == 0
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&& c1->output_sec == c2->output_sec
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&& c1->per_encoding == c2->per_encoding
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&& c1->lsda_encoding == c2->lsda_encoding
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&& c1->fde_encoding == c2->fde_encoding
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&& c1->initial_insn_length == c2->initial_insn_length
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&& memcmp (c1->initial_instructions,
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c2->initial_instructions,
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c1->initial_insn_length) == 0)
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return 1;
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return 0;
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}
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static hashval_t
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cie_hash (const void *e)
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{
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const struct cie *c = (const struct cie *) e;
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return c->hash;
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}
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static hashval_t
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cie_compute_hash (struct cie *c)
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{
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hashval_t h = 0;
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h = iterative_hash_object (c->length, h);
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h = iterative_hash_object (c->version, h);
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h = iterative_hash (c->augmentation, strlen (c->augmentation) + 1, h);
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h = iterative_hash_object (c->code_align, h);
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h = iterative_hash_object (c->data_align, h);
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h = iterative_hash_object (c->ra_column, h);
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h = iterative_hash_object (c->augmentation_size, h);
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h = iterative_hash_object (c->personality, h);
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h = iterative_hash_object (c->output_sec, h);
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h = iterative_hash_object (c->per_encoding, h);
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h = iterative_hash_object (c->lsda_encoding, h);
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h = iterative_hash_object (c->fde_encoding, h);
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h = iterative_hash_object (c->initial_insn_length, h);
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h = iterative_hash (c->initial_instructions, c->initial_insn_length, h);
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c->hash = h;
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return h;
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}
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/* Return the number of extra bytes that we'll be inserting into
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ENTRY's augmentation string. */
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static INLINE unsigned int
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extra_augmentation_string_bytes (struct eh_cie_fde *entry)
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{
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unsigned int size = 0;
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if (entry->cie)
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{
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if (entry->add_augmentation_size)
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size++;
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if (entry->u.cie.add_fde_encoding)
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size++;
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}
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return size;
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}
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/* Likewise ENTRY's augmentation data. */
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static INLINE unsigned int
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extra_augmentation_data_bytes (struct eh_cie_fde *entry)
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{
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unsigned int size = 0;
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if (entry->add_augmentation_size)
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size++;
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if (entry->cie && entry->u.cie.add_fde_encoding)
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size++;
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return size;
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}
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/* Return the size that ENTRY will have in the output. ALIGNMENT is the
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required alignment of ENTRY in bytes. */
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static unsigned int
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size_of_output_cie_fde (struct eh_cie_fde *entry, unsigned int alignment)
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{
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if (entry->removed)
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return 0;
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if (entry->size == 4)
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return 4;
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return (entry->size
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+ extra_augmentation_string_bytes (entry)
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+ extra_augmentation_data_bytes (entry)
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+ alignment - 1) & -alignment;
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}
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/* Assume that the bytes between *ITER and END are CFA instructions.
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Try to move *ITER past the first instruction and return true on
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success. ENCODED_PTR_WIDTH gives the width of pointer entries. */
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static bfd_boolean
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skip_cfa_op (bfd_byte **iter, bfd_byte *end, unsigned int encoded_ptr_width)
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{
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bfd_byte op;
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bfd_vma length;
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if (!read_byte (iter, end, &op))
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return FALSE;
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switch (op & 0xc0 ? op & 0xc0 : op)
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{
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case DW_CFA_nop:
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case DW_CFA_advance_loc:
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case DW_CFA_restore:
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case DW_CFA_remember_state:
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case DW_CFA_restore_state:
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case DW_CFA_GNU_window_save:
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/* No arguments. */
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return TRUE;
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case DW_CFA_offset:
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case DW_CFA_restore_extended:
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case DW_CFA_undefined:
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case DW_CFA_same_value:
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case DW_CFA_def_cfa_register:
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case DW_CFA_def_cfa_offset:
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case DW_CFA_def_cfa_offset_sf:
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case DW_CFA_GNU_args_size:
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/* One leb128 argument. */
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return skip_leb128 (iter, end);
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case DW_CFA_val_offset:
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case DW_CFA_val_offset_sf:
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case DW_CFA_offset_extended:
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case DW_CFA_register:
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case DW_CFA_def_cfa:
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case DW_CFA_offset_extended_sf:
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case DW_CFA_GNU_negative_offset_extended:
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case DW_CFA_def_cfa_sf:
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/* Two leb128 arguments. */
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return (skip_leb128 (iter, end)
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&& skip_leb128 (iter, end));
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case DW_CFA_def_cfa_expression:
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/* A variable-length argument. */
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return (read_uleb128 (iter, end, &length)
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&& skip_bytes (iter, end, length));
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case DW_CFA_expression:
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case DW_CFA_val_expression:
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/* A leb128 followed by a variable-length argument. */
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return (skip_leb128 (iter, end)
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&& read_uleb128 (iter, end, &length)
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&& skip_bytes (iter, end, length));
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case DW_CFA_set_loc:
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return skip_bytes (iter, end, encoded_ptr_width);
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case DW_CFA_advance_loc1:
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return skip_bytes (iter, end, 1);
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case DW_CFA_advance_loc2:
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return skip_bytes (iter, end, 2);
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case DW_CFA_advance_loc4:
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return skip_bytes (iter, end, 4);
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case DW_CFA_MIPS_advance_loc8:
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return skip_bytes (iter, end, 8);
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default:
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return FALSE;
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}
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}
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/* Try to interpret the bytes between BUF and END as CFA instructions.
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If every byte makes sense, return a pointer to the first DW_CFA_nop
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padding byte, or END if there is no padding. Return null otherwise.
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ENCODED_PTR_WIDTH is as for skip_cfa_op. */
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static bfd_byte *
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skip_non_nops (bfd_byte *buf, bfd_byte *end, unsigned int encoded_ptr_width,
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unsigned int *set_loc_count)
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{
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bfd_byte *last;
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last = buf;
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while (buf < end)
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if (*buf == DW_CFA_nop)
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buf++;
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else
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{
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if (*buf == DW_CFA_set_loc)
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++*set_loc_count;
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if (!skip_cfa_op (&buf, end, encoded_ptr_width))
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return 0;
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last = buf;
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}
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return last;
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}
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/* Convert absolute encoding ENCODING into PC-relative form.
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SIZE is the size of a pointer. */
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static unsigned char
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make_pc_relative (unsigned char encoding, unsigned int ptr_size)
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{
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if ((encoding & 0x7f) == DW_EH_PE_absptr)
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switch (ptr_size)
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{
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case 2:
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encoding |= DW_EH_PE_sdata2;
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break;
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case 4:
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encoding |= DW_EH_PE_sdata4;
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break;
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case 8:
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encoding |= DW_EH_PE_sdata8;
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break;
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}
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return encoding | DW_EH_PE_pcrel;
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}
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/* Called before calling _bfd_elf_parse_eh_frame on every input bfd's
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.eh_frame section. */
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void
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_bfd_elf_begin_eh_frame_parsing (struct bfd_link_info *info)
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{
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struct eh_frame_hdr_info *hdr_info;
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hdr_info = &elf_hash_table (info)->eh_info;
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hdr_info->merge_cies = !info->relocatable;
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}
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/* Try to parse .eh_frame section SEC, which belongs to ABFD. Store the
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information in the section's sec_info field on success. COOKIE
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describes the relocations in SEC. */
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void
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_bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
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asection *sec, struct elf_reloc_cookie *cookie)
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{
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#define REQUIRE(COND) \
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do \
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if (!(COND)) \
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goto free_no_table; \
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while (0)
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bfd_byte *ehbuf = NULL, *buf, *end;
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bfd_byte *last_fde;
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struct eh_cie_fde *this_inf;
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unsigned int hdr_length, hdr_id;
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unsigned int cie_count;
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struct cie *cie, *local_cies = NULL;
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struct elf_link_hash_table *htab;
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struct eh_frame_hdr_info *hdr_info;
|
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struct eh_frame_sec_info *sec_info = NULL;
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unsigned int ptr_size;
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unsigned int num_cies;
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unsigned int num_entries;
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elf_gc_mark_hook_fn gc_mark_hook;
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htab = elf_hash_table (info);
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hdr_info = &htab->eh_info;
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if (hdr_info->parsed_eh_frames)
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return;
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|
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if (sec->size == 0)
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{
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/* This file does not contain .eh_frame information. */
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return;
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}
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|
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if (bfd_is_abs_section (sec->output_section))
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{
|
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/* At least one of the sections is being discarded from the
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link, so we should just ignore them. */
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return;
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}
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|
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/* Read the frame unwind information from abfd. */
|
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|
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REQUIRE (bfd_malloc_and_get_section (abfd, sec, &ehbuf));
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|
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if (sec->size >= 4
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&& bfd_get_32 (abfd, ehbuf) == 0
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&& cookie->rel == cookie->relend)
|
|
{
|
|
/* Empty .eh_frame section. */
|
|
free (ehbuf);
|
|
return;
|
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}
|
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|
|
/* 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);
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|
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ptr_size = (get_elf_backend_data (abfd)
|
|
->elf_backend_eh_frame_address_size (abfd, sec));
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REQUIRE (ptr_size != 0);
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|
|
/* 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. */
|
|
local_cies = (struct cie *) bfd_zmalloc (num_cies * sizeof (*local_cies));
|
|
REQUIRE (local_cies);
|
|
|
|
/* FIXME: octets_per_byte. */
|
|
#define ENSURE_NO_RELOCS(buf) \
|
|
REQUIRE (!(cookie->rel < cookie->relend \
|
|
&& (cookie->rel->r_offset \
|
|
< (bfd_size_type) ((buf) - ehbuf)) \
|
|
&& cookie->rel->r_info != 0))
|
|
|
|
/* 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. */
|
|
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;
|
|
cie->output_sec = sec->output_section;
|
|
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;
|
|
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 '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));
|
|
}
|
|
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;
|
|
}
|
|
}
|
|
|
|
/* For shared libraries, try to get rid of as many RELATIVE relocs
|
|
as possible. */
|
|
if (info->shared
|
|
&& (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;
|
|
if (initial_insn_length <= sizeof (cie->initial_instructions))
|
|
{
|
|
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);
|
|
|
|
if (hdr_info->merge_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
|
|
{
|
|
asection *rsec;
|
|
|
|
/* 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);
|
|
REQUIRE (GET_RELOC (buf));
|
|
|
|
/* Chain together the FDEs for each section. */
|
|
rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook, cookie);
|
|
/* 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 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 = ELF_INFO_TYPE_EH_FRAME;
|
|
if (hdr_info->merge_cies)
|
|
{
|
|
sec_info->cies = local_cies;
|
|
local_cies = NULL;
|
|
}
|
|
goto success;
|
|
|
|
free_no_table:
|
|
(*info->callbacks->einfo)
|
|
(_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"),
|
|
abfd, sec);
|
|
hdr_info->table = FALSE;
|
|
if (sec_info)
|
|
free (sec_info);
|
|
success:
|
|
if (ehbuf)
|
|
free (ehbuf);
|
|
if (local_cies)
|
|
free (local_cies);
|
|
#undef REQUIRE
|
|
}
|
|
|
|
/* Finish a pass over all .eh_frame sections. */
|
|
|
|
void
|
|
_bfd_elf_end_eh_frame_parsing (struct bfd_link_info *info)
|
|
{
|
|
struct eh_frame_hdr_info *hdr_info;
|
|
|
|
hdr_info = &elf_hash_table (info)->eh_info;
|
|
hdr_info->parsed_eh_frames = 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 bfd_boolean
|
|
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. */
|
|
|
|
bfd_boolean
|
|
_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->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)
|
|
{
|
|
bfd_boolean per_binds_local;
|
|
|
|
/* Work out the address of personality routine, either as an absolute
|
|
value or as a symbol. */
|
|
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.val = (sym->st_value
|
|
+ sym_sec->output_offset
|
|
+ sym_sec->output_section->vma);
|
|
per_binds_local = TRUE;
|
|
}
|
|
|
|
if (per_binds_local
|
|
&& info->shared
|
|
&& (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->output_sec = sec->output_section;
|
|
cie_compute_hash (cie);
|
|
if (hdr_info->cies == NULL)
|
|
{
|
|
hdr_info->cies = htab_try_create (1, cie_hash, cie_eq, free);
|
|
if (hdr_info->cies == NULL)
|
|
return cie_inf;
|
|
}
|
|
loc = htab_find_slot_with_hash (hdr_info->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;
|
|
}
|
|
|
|
/* 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. */
|
|
|
|
bfd_boolean
|
|
_bfd_elf_discard_section_eh_frame
|
|
(bfd *abfd, struct bfd_link_info *info, asection *sec,
|
|
bfd_boolean (*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;
|
|
|
|
sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info;
|
|
if (sec_info == NULL)
|
|
return FALSE;
|
|
|
|
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)
|
|
{
|
|
cookie->rel = cookie->rels + ent->reloc_index;
|
|
/* FIXME: octets_per_byte. */
|
|
BFD_ASSERT (cookie->rel < cookie->relend
|
|
&& cookie->rel->r_offset == ent->offset + 8);
|
|
if (!(*reloc_symbol_deleted_p) (ent->offset + 8, cookie))
|
|
{
|
|
if (info->shared
|
|
&& (((ent->fde_encoding & 0x70) == DW_EH_PE_absptr
|
|
&& ent->make_relative == 0)
|
|
|| (ent->fde_encoding & 0x70) == DW_EH_PE_aligned))
|
|
{
|
|
/* 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->table = FALSE;
|
|
(*info->callbacks->einfo)
|
|
(_("%P: fde encoding in %B(%A) prevents .eh_frame_hdr"
|
|
" table being created.\n"), abfd, sec);
|
|
}
|
|
ent->removed = 0;
|
|
hdr_info->fde_count++;
|
|
ent->u.fde.cie_inf = find_merged_cie (abfd, info, sec, hdr_info,
|
|
cookie, ent->u.fde.cie_inf);
|
|
}
|
|
}
|
|
|
|
if (sec_info->cies)
|
|
{
|
|
free (sec_info->cies);
|
|
sec_info->cies = NULL;
|
|
}
|
|
|
|
ptr_size = (get_elf_backend_data (sec->owner)
|
|
->elf_backend_eh_frame_address_size (sec->owner, sec));
|
|
offset = 0;
|
|
for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent)
|
|
if (!ent->removed)
|
|
{
|
|
ent->new_offset = offset;
|
|
offset += size_of_output_cie_fde (ent, ptr_size);
|
|
}
|
|
|
|
sec->rawsize = sec->size;
|
|
sec->size = offset;
|
|
return offset != sec->rawsize;
|
|
}
|
|
|
|
/* 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. */
|
|
|
|
bfd_boolean
|
|
_bfd_elf_discard_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;
|
|
|
|
if (hdr_info->cies != NULL)
|
|
{
|
|
htab_delete (hdr_info->cies);
|
|
hdr_info->cies = NULL;
|
|
}
|
|
|
|
sec = hdr_info->hdr_sec;
|
|
if (sec == NULL)
|
|
return FALSE;
|
|
|
|
sec->size = EH_FRAME_HDR_SIZE;
|
|
if (hdr_info->table)
|
|
sec->size += 4 + hdr_info->fde_count * 8;
|
|
|
|
elf_tdata (abfd)->eh_frame_hdr = sec;
|
|
return TRUE;
|
|
}
|
|
|
|
/* 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. */
|
|
|
|
bfd_boolean
|
|
_bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info)
|
|
{
|
|
asection *o;
|
|
bfd *abfd;
|
|
struct elf_link_hash_table *htab;
|
|
struct eh_frame_hdr_info *hdr_info;
|
|
|
|
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))
|
|
{
|
|
hdr_info->hdr_sec = NULL;
|
|
return TRUE;
|
|
}
|
|
|
|
abfd = NULL;
|
|
if (info->eh_frame_hdr)
|
|
for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next)
|
|
{
|
|
/* Count only sections which have at least a single CIE or FDE.
|
|
There cannot be any CIE or FDE <= 8 bytes. */
|
|
o = bfd_get_section_by_name (abfd, ".eh_frame");
|
|
if (o && o->size > 8 && !bfd_is_abs_section (o->output_section))
|
|
break;
|
|
}
|
|
|
|
if (abfd == NULL)
|
|
{
|
|
hdr_info->hdr_sec->flags |= SEC_EXCLUDE;
|
|
hdr_info->hdr_sec = NULL;
|
|
return TRUE;
|
|
}
|
|
|
|
hdr_info->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,
|
|
asection *sec,
|
|
bfd_vma offset)
|
|
{
|
|
struct eh_frame_sec_info *sec_info;
|
|
struct elf_link_hash_table *htab;
|
|
struct eh_frame_hdr_info *hdr_info;
|
|
unsigned int lo, hi, mid;
|
|
|
|
if (sec->sec_info_type != ELF_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;
|
|
|
|
htab = elf_hash_table (info);
|
|
hdr_info = &htab->eh_info;
|
|
|
|
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 section. This is called with the relocated
|
|
contents. */
|
|
|
|
bfd_boolean
|
|
_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;
|
|
|
|
if (sec->sec_info_type != ELF_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->table && hdr_info->array == NULL)
|
|
hdr_info->array = (struct eh_frame_array_ent *)
|
|
bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array));
|
|
if (hdr_info->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);
|
|
|
|
for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++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 == sec_info->entry + sec_info->count - 1);
|
|
continue;
|
|
}
|
|
|
|
buf = contents + ent->new_offset;
|
|
end = buf + ent->size;
|
|
new_size = size_of_output_cie_fde (ent, ptr_size);
|
|
|
|
/* 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 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 and version. */
|
|
buf += 9;
|
|
aug = (char *) buf;
|
|
buf += strlen (aug) + 1;
|
|
skip_leb128 (&buf, end);
|
|
skip_leb128 (&buf, end);
|
|
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);
|
|
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:
|
|
{
|
|
asection *got = bfd_get_section_by_name (abfd, ".got");
|
|
|
|
BFD_ASSERT (got != NULL);
|
|
address += got->vma;
|
|
}
|
|
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)
|
|
{
|
|
hdr_info->array[hdr_info->array_count].initial_loc = address;
|
|
hdr_info->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);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* 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. */
|
|
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->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;
|
|
return 0;
|
|
}
|
|
|
|
/* 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.
|
|
.eh_frame_hdr format:
|
|
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). */
|
|
|
|
bfd_boolean
|
|
_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;
|
|
bfd_byte *contents;
|
|
asection *eh_frame_sec;
|
|
bfd_size_type size;
|
|
bfd_boolean retval;
|
|
bfd_vma encoded_eh_frame;
|
|
|
|
htab = elf_hash_table (info);
|
|
hdr_info = &htab->eh_info;
|
|
sec = hdr_info->hdr_sec;
|
|
if (sec == NULL)
|
|
return TRUE;
|
|
|
|
size = EH_FRAME_HDR_SIZE;
|
|
if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count)
|
|
size += 4 + hdr_info->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);
|
|
contents[0] = 1; /* Version. */
|
|
contents[1] = get_elf_backend_data (abfd)->elf_backend_encode_eh_address
|
|
(abfd, info, eh_frame_sec, 0, sec, 4,
|
|
&encoded_eh_frame); /* .eh_frame offset. */
|
|
|
|
if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count)
|
|
{
|
|
contents[2] = DW_EH_PE_udata4; /* FDE count encoding. */
|
|
contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; /* Search table enc. */
|
|
}
|
|
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;
|
|
|
|
bfd_put_32 (abfd, hdr_info->fde_count, contents + EH_FRAME_HDR_SIZE);
|
|
qsort (hdr_info->array, hdr_info->fde_count, sizeof (*hdr_info->array),
|
|
vma_compare);
|
|
for (i = 0; i < hdr_info->fde_count; i++)
|
|
{
|
|
bfd_put_32 (abfd,
|
|
hdr_info->array[i].initial_loc
|
|
- sec->output_section->vma,
|
|
contents + EH_FRAME_HDR_SIZE + i * 8 + 4);
|
|
bfd_put_32 (abfd,
|
|
hdr_info->array[i].fde - sec->output_section->vma,
|
|
contents + EH_FRAME_HDR_SIZE + i * 8 + 8);
|
|
}
|
|
}
|
|
|
|
/* FIXME: octets_per_byte. */
|
|
retval = bfd_set_section_contents (abfd, sec->output_section,
|
|
contents, (file_ptr) sec->output_offset,
|
|
sec->size);
|
|
free (contents);
|
|
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. */
|
|
|
|
bfd_boolean
|
|
_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;
|
|
}
|