646 lines
18 KiB
C
646 lines
18 KiB
C
/* Stabs in sections linking support.
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Copyright 1996, 1997, 1998 Free Software Foundation, Inc.
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Written by Ian Lance Taylor, Cygnus Support.
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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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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/* This file contains support for linking stabs in sections, as used
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on COFF and ELF. */
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#include "bfd.h"
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#include "sysdep.h"
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#include "libbfd.h"
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#include "aout/stab_gnu.h"
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#include <ctype.h>
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/* Stabs entries use a 12 byte format:
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4 byte string table index
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1 byte stab type
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1 byte stab other field
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2 byte stab desc field
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4 byte stab value
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FIXME: This will have to change for a 64 bit object format.
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The stabs symbols are divided into compilation units. For the
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first entry in each unit, the type of 0, the value is the length of
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the string table for this unit, and the desc field is the number of
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stabs symbols for this unit. */
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#define STRDXOFF (0)
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#define TYPEOFF (4)
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#define OTHEROFF (5)
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#define DESCOFF (6)
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#define VALOFF (8)
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#define STABSIZE (12)
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/* A hash table used for header files with N_BINCL entries. */
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struct stab_link_includes_table
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{
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struct bfd_hash_table root;
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};
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/* A linked list of totals that we have found for a particular header
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file. */
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struct stab_link_includes_totals
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{
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struct stab_link_includes_totals *next;
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bfd_vma total;
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};
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/* An entry in the header file hash table. */
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struct stab_link_includes_entry
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{
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struct bfd_hash_entry root;
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/* List of totals we have found for this file. */
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struct stab_link_includes_totals *totals;
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};
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/* Look up an entry in an the header file hash table. */
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#define stab_link_includes_lookup(table, string, create, copy) \
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((struct stab_link_includes_entry *) \
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bfd_hash_lookup (&(table)->root, (string), (create), (copy)))
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/* This structure is used to hold a list of N_BINCL symbols, some of
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which might be converted into N_EXCL symbols. */
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struct stab_excl_list
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{
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/* The next symbol to convert. */
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struct stab_excl_list *next;
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/* The offset to this symbol in the section contents. */
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bfd_size_type offset;
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/* The value to use for the symbol. */
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bfd_vma val;
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/* The type of this symbol (N_BINCL or N_EXCL). */
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int type;
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};
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/* This structure is stored with each .stab section. */
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struct stab_section_info
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{
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/* This is a linked list of N_BINCL symbols which should be
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converted into N_EXCL symbols. */
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struct stab_excl_list *excls;
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/* This is used to map input stab offsets within their sections
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to output stab offsets, to take into account stabs that have
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been deleted. If it is NULL, the output offsets are the same
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as the input offsets, because no stabs have been deleted from
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this section. Otherwise the i'th entry is the number of
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bytes of stabs that have been deleted prior to the i'th
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stab. */
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bfd_size_type *cumulative_skips;
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/* This is an array of string indices. For each stab symbol, we
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store the string index here. If a stab symbol should not be
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included in the final output, the string index is -1. */
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bfd_size_type stridxs[1];
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};
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/* This structure is used to keep track of stabs in sections
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information while linking. */
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struct stab_info
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{
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/* A hash table used to hold stabs strings. */
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struct bfd_strtab_hash *strings;
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/* The header file hash table. */
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struct stab_link_includes_table includes;
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/* The first .stabstr section. */
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asection *stabstr;
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};
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static struct bfd_hash_entry *stab_link_includes_newfunc
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PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
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/* The function to create a new entry in the header file hash table. */
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static struct bfd_hash_entry *
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stab_link_includes_newfunc (entry, table, string)
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struct bfd_hash_entry *entry;
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struct bfd_hash_table *table;
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const char *string;
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{
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struct stab_link_includes_entry *ret =
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(struct stab_link_includes_entry *) entry;
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/* Allocate the structure if it has not already been allocated by a
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subclass. */
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if (ret == (struct stab_link_includes_entry *) NULL)
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ret = ((struct stab_link_includes_entry *)
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bfd_hash_allocate (table,
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sizeof (struct stab_link_includes_entry)));
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if (ret == (struct stab_link_includes_entry *) NULL)
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return (struct bfd_hash_entry *) ret;
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/* Call the allocation method of the superclass. */
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ret = ((struct stab_link_includes_entry *)
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bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
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if (ret)
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{
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/* Set local fields. */
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ret->totals = NULL;
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}
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return (struct bfd_hash_entry *) ret;
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}
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/* This function is called for each input file from the add_symbols
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pass of the linker. */
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boolean
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_bfd_link_section_stabs (abfd, psinfo, stabsec, stabstrsec, psecinfo)
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bfd *abfd;
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PTR *psinfo;
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asection *stabsec;
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asection *stabstrsec;
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PTR *psecinfo;
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{
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boolean first;
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struct stab_info *sinfo;
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bfd_size_type count;
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struct stab_section_info *secinfo;
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bfd_byte *stabbuf = NULL;
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bfd_byte *stabstrbuf = NULL;
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bfd_byte *sym, *symend;
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bfd_size_type stroff, next_stroff, skip;
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bfd_size_type *pstridx;
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if (stabsec->_raw_size == 0
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|| stabstrsec->_raw_size == 0)
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{
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/* This file does not contain stabs debugging information. */
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return true;
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}
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if (stabsec->_raw_size % STABSIZE != 0)
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{
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/* Something is wrong with the format of these stab symbols.
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Don't try to optimize them. */
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return true;
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}
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if ((stabstrsec->flags & SEC_RELOC) != 0)
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{
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/* We shouldn't see relocations in the strings, and we aren't
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prepared to handle them. */
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return true;
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}
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if ((stabsec->output_section != NULL
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&& bfd_is_abs_section (stabsec->output_section))
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|| (stabstrsec->output_section != NULL
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&& bfd_is_abs_section (stabstrsec->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 true;
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}
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first = false;
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if (*psinfo == NULL)
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{
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/* Initialize the stabs information we need to keep track of. */
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first = true;
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*psinfo = (PTR) bfd_alloc (abfd, sizeof (struct stab_info));
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if (*psinfo == NULL)
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goto error_return;
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sinfo = (struct stab_info *) *psinfo;
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sinfo->strings = _bfd_stringtab_init ();
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if (sinfo->strings == NULL)
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goto error_return;
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if (! bfd_hash_table_init_n (&sinfo->includes.root,
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stab_link_includes_newfunc,
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251))
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goto error_return;
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sinfo->stabstr = bfd_make_section_anyway (abfd, ".stabstr");
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sinfo->stabstr->flags |= SEC_HAS_CONTENTS | SEC_READONLY | SEC_DEBUGGING;
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}
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sinfo = (struct stab_info *) *psinfo;
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/* Initialize the information we are going to store for this .stab
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section. */
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count = stabsec->_raw_size / STABSIZE;
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*psecinfo = bfd_alloc (abfd,
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(sizeof (struct stab_section_info)
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+ (count - 1) * sizeof (bfd_size_type)));
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if (*psecinfo == NULL)
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goto error_return;
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secinfo = (struct stab_section_info *) *psecinfo;
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secinfo->excls = NULL;
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secinfo->cumulative_skips = NULL;
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memset (secinfo->stridxs, 0, count * sizeof (bfd_size_type));
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/* Read the stabs information from abfd. */
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stabbuf = (bfd_byte *) bfd_malloc (stabsec->_raw_size);
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stabstrbuf = (bfd_byte *) bfd_malloc (stabstrsec->_raw_size);
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if (stabbuf == NULL || stabstrbuf == NULL)
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goto error_return;
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if (! bfd_get_section_contents (abfd, stabsec, stabbuf, 0,
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stabsec->_raw_size)
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|| ! bfd_get_section_contents (abfd, stabstrsec, stabstrbuf, 0,
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stabstrsec->_raw_size))
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goto error_return;
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/* Look through the stabs symbols, work out the new string indices,
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and identify N_BINCL symbols which can be eliminated. */
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stroff = 0;
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next_stroff = 0;
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skip = 0;
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symend = stabbuf + stabsec->_raw_size;
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for (sym = stabbuf, pstridx = secinfo->stridxs;
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sym < symend;
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sym += STABSIZE, ++pstridx)
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{
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int type;
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const char *string;
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if (*pstridx != 0)
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{
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/* This symbol has already been handled by an N_BINCL pass. */
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continue;
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}
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type = sym[TYPEOFF];
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if (type == 0)
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{
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/* Special type 0 stabs indicate the offset to the next
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string table. We only copy the very first one. */
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stroff = next_stroff;
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next_stroff += bfd_get_32 (abfd, sym + 8);
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if (! first)
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{
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*pstridx = (bfd_size_type) -1;
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++skip;
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continue;
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}
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first = false;
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}
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/* Store the string in the hash table, and record the index. */
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string = ((char *) stabstrbuf
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+ stroff
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+ bfd_get_32 (abfd, sym + STRDXOFF));
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*pstridx = _bfd_stringtab_add (sinfo->strings, string, true, true);
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/* An N_BINCL symbol indicates the start of the stabs entries
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for a header file. We need to scan ahead to the next N_EINCL
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symbol, ignoring nesting, adding up all the characters in the
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symbol names, not including the file numbers in types (the
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first number after an open parenthesis). */
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if (type == N_BINCL)
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{
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bfd_vma val;
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int nest;
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bfd_byte *incl_sym;
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struct stab_link_includes_entry *incl_entry;
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struct stab_link_includes_totals *t;
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struct stab_excl_list *ne;
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val = 0;
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nest = 0;
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for (incl_sym = sym + STABSIZE;
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incl_sym < symend;
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incl_sym += STABSIZE)
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{
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int incl_type;
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incl_type = incl_sym[TYPEOFF];
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if (incl_type == 0)
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break;
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else if (incl_type == N_EINCL)
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{
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if (nest == 0)
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break;
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--nest;
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}
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else if (incl_type == N_BINCL)
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++nest;
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else if (nest == 0)
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{
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const char *str;
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str = ((char *) stabstrbuf
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+ stroff
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+ bfd_get_32 (abfd, incl_sym + STRDXOFF));
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for (; *str != '\0'; str++)
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{
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val += *str;
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if (*str == '(')
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{
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/* Skip the file number. */
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++str;
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while (isdigit ((unsigned char) *str))
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++str;
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--str;
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}
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}
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}
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}
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/* If we have already included a header file with the same
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value, then replaced this one with an N_EXCL symbol. */
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incl_entry = stab_link_includes_lookup (&sinfo->includes, string,
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true, true);
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if (incl_entry == NULL)
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goto error_return;
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for (t = incl_entry->totals; t != NULL; t = t->next)
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if (t->total == val)
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break;
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/* Record this symbol, so that we can set the value
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correctly. */
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ne = (struct stab_excl_list *) bfd_alloc (abfd, sizeof *ne);
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if (ne == NULL)
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goto error_return;
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ne->offset = sym - stabbuf;
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ne->val = val;
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ne->type = N_BINCL;
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ne->next = secinfo->excls;
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secinfo->excls = ne;
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if (t == NULL)
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{
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/* This is the first time we have seen this header file
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with this set of stabs strings. */
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t = ((struct stab_link_includes_totals *)
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bfd_hash_allocate (&sinfo->includes.root, sizeof *t));
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if (t == NULL)
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goto error_return;
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t->total = val;
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t->next = incl_entry->totals;
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incl_entry->totals = t;
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}
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else
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{
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bfd_size_type *incl_pstridx;
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/* We have seen this header file before. Tell the final
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pass to change the type to N_EXCL. */
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ne->type = N_EXCL;
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/* Mark the skipped symbols. */
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nest = 0;
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for (incl_sym = sym + STABSIZE, incl_pstridx = pstridx + 1;
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incl_sym < symend;
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incl_sym += STABSIZE, ++incl_pstridx)
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{
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int incl_type;
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incl_type = incl_sym[TYPEOFF];
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if (incl_type == N_EINCL)
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{
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if (nest == 0)
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{
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*incl_pstridx = (bfd_size_type) -1;
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++skip;
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break;
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}
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--nest;
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}
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else if (incl_type == N_BINCL)
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++nest;
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else if (nest == 0)
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{
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*incl_pstridx = (bfd_size_type) -1;
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++skip;
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}
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}
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}
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}
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}
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free (stabbuf);
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stabbuf = NULL;
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free (stabstrbuf);
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stabstrbuf = NULL;
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/* We need to set the section sizes such that the linker will
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compute the output section sizes correctly. We set the .stab
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size to not include the entries we don't want. We set
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SEC_EXCLUDE for the .stabstr section, so that it will be dropped
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from the link. We record the size of the strtab in the first
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.stabstr section we saw, and make sure we don't set SEC_EXCLUDE
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for that section. */
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stabsec->_cooked_size = (count - skip) * STABSIZE;
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if (stabsec->_cooked_size == 0)
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stabsec->flags |= SEC_EXCLUDE;
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stabstrsec->flags |= SEC_EXCLUDE;
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sinfo->stabstr->_cooked_size = _bfd_stringtab_size (sinfo->strings);
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/* Calculate the `cumulative_skips' array now that stabs have been
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deleted for this section. */
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if (skip != 0)
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{
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bfd_size_type i, offset;
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bfd_size_type *pskips;
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secinfo->cumulative_skips =
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(bfd_size_type *) bfd_alloc (abfd, count * sizeof (bfd_size_type));
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if (secinfo->cumulative_skips == NULL)
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goto error_return;
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pskips = secinfo->cumulative_skips;
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pstridx = secinfo->stridxs;
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offset = 0;
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for (i = 0; i < count; i++, pskips++, pstridx++)
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{
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*pskips = offset;
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if (*pstridx == (bfd_size_type) -1)
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offset += STABSIZE;
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}
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BFD_ASSERT (offset != 0);
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}
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return true;
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error_return:
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if (stabbuf != NULL)
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free (stabbuf);
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if (stabstrbuf != NULL)
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free (stabstrbuf);
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return false;
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}
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/* Write out the stab section. This is called with the relocated
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contents. */
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boolean
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_bfd_write_section_stabs (output_bfd, psinfo, stabsec, psecinfo, contents)
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bfd *output_bfd;
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PTR *psinfo;
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asection *stabsec;
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PTR *psecinfo;
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bfd_byte *contents;
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{
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struct stab_info *sinfo;
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struct stab_section_info *secinfo;
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struct stab_excl_list *e;
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bfd_byte *sym, *tosym, *symend;
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bfd_size_type *pstridx;
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sinfo = (struct stab_info *) *psinfo;
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secinfo = (struct stab_section_info *) *psecinfo;
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if (secinfo == NULL)
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return bfd_set_section_contents (output_bfd, stabsec->output_section,
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contents, stabsec->output_offset,
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stabsec->_raw_size);
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/* Handle each N_BINCL entry. */
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for (e = secinfo->excls; e != NULL; e = e->next)
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{
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bfd_byte *excl_sym;
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BFD_ASSERT (e->offset < stabsec->_raw_size);
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excl_sym = contents + e->offset;
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bfd_put_32 (output_bfd, e->val, excl_sym + VALOFF);
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excl_sym[TYPEOFF] = e->type;
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}
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|
||
/* Copy over all the stabs symbols, omitting the ones we don't want,
|
||
and correcting the string indices for those we do want. */
|
||
tosym = contents;
|
||
symend = contents + stabsec->_raw_size;
|
||
for (sym = contents, pstridx = secinfo->stridxs;
|
||
sym < symend;
|
||
sym += STABSIZE, ++pstridx)
|
||
{
|
||
if (*pstridx != (bfd_size_type) -1)
|
||
{
|
||
if (tosym != sym)
|
||
memcpy (tosym, sym, STABSIZE);
|
||
bfd_put_32 (output_bfd, *pstridx, tosym + STRDXOFF);
|
||
|
||
if (sym[TYPEOFF] == 0)
|
||
{
|
||
/* This is the header symbol for the stabs section. We
|
||
don't really need one, since we have merged all the
|
||
input stabs sections into one, but we generate one
|
||
for the benefit of readers which expect to see one. */
|
||
BFD_ASSERT (sym == contents);
|
||
bfd_put_32 (output_bfd, _bfd_stringtab_size (sinfo->strings),
|
||
tosym + VALOFF);
|
||
bfd_put_16 (output_bfd,
|
||
stabsec->output_section->_raw_size / STABSIZE - 1,
|
||
tosym + DESCOFF);
|
||
}
|
||
|
||
tosym += STABSIZE;
|
||
}
|
||
}
|
||
|
||
BFD_ASSERT ((bfd_size_type) (tosym - contents) == stabsec->_cooked_size);
|
||
|
||
return bfd_set_section_contents (output_bfd, stabsec->output_section,
|
||
contents, stabsec->output_offset,
|
||
stabsec->_cooked_size);
|
||
}
|
||
|
||
/* Write out the .stabstr section. */
|
||
|
||
boolean
|
||
_bfd_write_stab_strings (output_bfd, psinfo)
|
||
bfd *output_bfd;
|
||
PTR *psinfo;
|
||
{
|
||
struct stab_info *sinfo;
|
||
|
||
sinfo = (struct stab_info *) *psinfo;
|
||
|
||
if (sinfo == NULL)
|
||
return true;
|
||
|
||
BFD_ASSERT ((sinfo->stabstr->output_offset
|
||
+ _bfd_stringtab_size (sinfo->strings))
|
||
<= sinfo->stabstr->output_section->_raw_size);
|
||
|
||
if (bfd_seek (output_bfd,
|
||
(sinfo->stabstr->output_section->filepos
|
||
+ sinfo->stabstr->output_offset),
|
||
SEEK_SET) != 0)
|
||
return false;
|
||
|
||
if (! _bfd_stringtab_emit (output_bfd, sinfo->strings))
|
||
return false;
|
||
|
||
/* We no longer need the stabs information. */
|
||
_bfd_stringtab_free (sinfo->strings);
|
||
bfd_hash_table_free (&sinfo->includes.root);
|
||
|
||
return true;
|
||
}
|
||
|
||
/* Adjust an address in the .stab section. Given OFFSET within
|
||
STABSEC, this returns the new offset in the adjusted stab section,
|
||
or -1 if the address refers to a stab which has been removed. */
|
||
|
||
bfd_vma
|
||
_bfd_stab_section_offset (output_bfd, psinfo, stabsec, psecinfo, offset)
|
||
bfd *output_bfd;
|
||
PTR *psinfo;
|
||
asection *stabsec;
|
||
PTR *psecinfo;
|
||
bfd_vma offset;
|
||
{
|
||
struct stab_section_info *secinfo;
|
||
|
||
secinfo = (struct stab_section_info *) *psecinfo;
|
||
|
||
if (secinfo == NULL)
|
||
return offset;
|
||
|
||
if (offset >= stabsec->_raw_size)
|
||
return offset - (stabsec->_cooked_size - stabsec->_raw_size);
|
||
|
||
if (secinfo->cumulative_skips)
|
||
{
|
||
bfd_vma i;
|
||
|
||
i = offset / STABSIZE;
|
||
|
||
if (secinfo->stridxs [i] == (bfd_size_type) -1)
|
||
return (bfd_vma) -1;
|
||
|
||
return offset - secinfo->cumulative_skips [i];
|
||
}
|
||
|
||
return offset;
|
||
}
|