diff options
Diffstat (limited to 'bfd/stabs.c')
| -rw-r--r-- | bfd/stabs.c | 651 |
1 files changed, 651 insertions, 0 deletions
diff --git a/bfd/stabs.c b/bfd/stabs.c new file mode 100644 index 0000000..ffc000d --- /dev/null +++ b/bfd/stabs.c @@ -0,0 +1,651 @@ +/* Stabs in sections linking support. + Copyright 1996, 1997, 1998 Free Software Foundation, Inc. + Written by Ian Lance Taylor, Cygnus Support. + +This file is part of BFD, the Binary File Descriptor library. + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +/* This file contains support for linking stabs in sections, as used + on COFF and ELF. */ + +#include "bfd.h" +#include "sysdep.h" +#include "libbfd.h" +#include "aout/stab_gnu.h" + +#include <ctype.h> + +/* Stabs entries use a 12 byte format: + 4 byte string table index + 1 byte stab type + 1 byte stab other field + 2 byte stab desc field + 4 byte stab value + FIXME: This will have to change for a 64 bit object format. + + The stabs symbols are divided into compilation units. For the + first entry in each unit, the type of 0, the value is the length of + the string table for this unit, and the desc field is the number of + stabs symbols for this unit. */ + +#define STRDXOFF (0) +#define TYPEOFF (4) +#define OTHEROFF (5) +#define DESCOFF (6) +#define VALOFF (8) +#define STABSIZE (12) + +/* A hash table used for header files with N_BINCL entries. */ + +struct stab_link_includes_table +{ + struct bfd_hash_table root; +}; + +/* A linked list of totals that we have found for a particular header + file. */ + +struct stab_link_includes_totals +{ + struct stab_link_includes_totals *next; + bfd_vma total; +}; + +/* An entry in the header file hash table. */ + +struct stab_link_includes_entry +{ + struct bfd_hash_entry root; + /* List of totals we have found for this file. */ + struct stab_link_includes_totals *totals; +}; + +/* Look up an entry in an the header file hash table. */ + +#define stab_link_includes_lookup(table, string, create, copy) \ + ((struct stab_link_includes_entry *) \ + bfd_hash_lookup (&(table)->root, (string), (create), (copy))) + +/* This structure is used to hold a list of N_BINCL symbols, some of + which might be converted into N_EXCL symbols. */ + +struct stab_excl_list +{ + /* The next symbol to convert. */ + struct stab_excl_list *next; + /* The offset to this symbol in the section contents. */ + bfd_size_type offset; + /* The value to use for the symbol. */ + bfd_vma val; + /* The type of this symbol (N_BINCL or N_EXCL). */ + int type; +}; + +/* This structure is stored with each .stab section. */ + +struct stab_section_info +{ + /* This is a linked list of N_BINCL symbols which should be + converted into N_EXCL symbols. */ + struct stab_excl_list *excls; + + /* This is used to map input stab offsets within their sections + to output stab offsets, to take into account stabs that have + been deleted. If it is NULL, the output offsets are the same + as the input offsets, because no stabs have been deleted from + this section. Otherwise the i'th entry is the number of + bytes of stabs that have been deleted prior to the i'th + stab. */ + bfd_size_type *cumulative_skips; + + /* This is an array of string indices. For each stab symbol, we + store the string index here. If a stab symbol should not be + included in the final output, the string index is -1. */ + bfd_size_type stridxs[1]; +}; + +/* This structure is used to keep track of stabs in sections + information while linking. */ + +struct stab_info +{ + /* A hash table used to hold stabs strings. */ + struct bfd_strtab_hash *strings; + /* The header file hash table. */ + struct stab_link_includes_table includes; + /* The first .stabstr section. */ + asection *stabstr; +}; + +static struct bfd_hash_entry *stab_link_includes_newfunc + PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); + +/* The function to create a new entry in the header file hash table. */ + +static struct bfd_hash_entry * +stab_link_includes_newfunc (entry, table, string) + struct bfd_hash_entry *entry; + struct bfd_hash_table *table; + const char *string; +{ + struct stab_link_includes_entry *ret = + (struct stab_link_includes_entry *) entry; + + /* Allocate the structure if it has not already been allocated by a + subclass. */ + if (ret == (struct stab_link_includes_entry *) NULL) + ret = ((struct stab_link_includes_entry *) + bfd_hash_allocate (table, + sizeof (struct stab_link_includes_entry))); + if (ret == (struct stab_link_includes_entry *) NULL) + return (struct bfd_hash_entry *) ret; + + /* Call the allocation method of the superclass. */ + ret = ((struct stab_link_includes_entry *) + bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); + if (ret) + { + /* Set local fields. */ + ret->totals = NULL; + } + + return (struct bfd_hash_entry *) ret; +} + +/* This function is called for each input file from the add_symbols + pass of the linker. */ + +boolean +_bfd_link_section_stabs (abfd, psinfo, stabsec, stabstrsec, psecinfo) + bfd *abfd; + PTR *psinfo; + asection *stabsec; + asection *stabstrsec; + PTR *psecinfo; +{ + boolean first; + struct stab_info *sinfo; + bfd_size_type count; + struct stab_section_info *secinfo; + bfd_byte *stabbuf = NULL; + bfd_byte *stabstrbuf = NULL; + bfd_byte *sym, *symend; + bfd_size_type stroff, next_stroff, skip; + bfd_size_type *pstridx; + + if (stabsec->_raw_size == 0 + || stabstrsec->_raw_size == 0) + { + /* This file does not contain stabs debugging information. */ + return true; + } + + if (stabsec->_raw_size % STABSIZE != 0) + { + /* Something is wrong with the format of these stab symbols. + Don't try to optimize them. */ + return true; + } + + if ((stabstrsec->flags & SEC_RELOC) != 0) + { + /* We shouldn't see relocations in the strings, and we aren't + prepared to handle them. */ + return true; + } + + if ((stabsec->output_section != NULL + && bfd_is_abs_section (stabsec->output_section)) + || (stabstrsec->output_section != NULL + && bfd_is_abs_section (stabstrsec->output_section))) + { + /* At least one of the sections is being discarded from the + link, so we should just ignore them. */ + return true; + } + + first = false; + + if (*psinfo == NULL) + { + /* Initialize the stabs information we need to keep track of. */ + first = true; + *psinfo = (PTR) bfd_alloc (abfd, sizeof (struct stab_info)); + if (*psinfo == NULL) + goto error_return; + sinfo = (struct stab_info *) *psinfo; + sinfo->strings = _bfd_stringtab_init (); + if (sinfo->strings == NULL) + goto error_return; + if (! bfd_hash_table_init_n (&sinfo->includes.root, + stab_link_includes_newfunc, + 251)) + goto error_return; + sinfo->stabstr = bfd_make_section_anyway (abfd, ".stabstr"); + sinfo->stabstr->flags |= SEC_HAS_CONTENTS | SEC_READONLY | SEC_DEBUGGING; + } + + sinfo = (struct stab_info *) *psinfo; + + /* Initialize the information we are going to store for this .stab + section. */ + + count = stabsec->_raw_size / STABSIZE; + + *psecinfo = bfd_alloc (abfd, + (sizeof (struct stab_section_info) + + (count - 1) * sizeof (bfd_size_type))); + if (*psecinfo == NULL) + goto error_return; + + secinfo = (struct stab_section_info *) *psecinfo; + secinfo->excls = NULL; + secinfo->cumulative_skips = NULL; + memset (secinfo->stridxs, 0, count * sizeof (bfd_size_type)); + + /* Read the stabs information from abfd. */ + + stabbuf = (bfd_byte *) bfd_malloc (stabsec->_raw_size); + stabstrbuf = (bfd_byte *) bfd_malloc (stabstrsec->_raw_size); + if (stabbuf == NULL || stabstrbuf == NULL) + goto error_return; + + if (! bfd_get_section_contents (abfd, stabsec, stabbuf, 0, + stabsec->_raw_size) + || ! bfd_get_section_contents (abfd, stabstrsec, stabstrbuf, 0, + stabstrsec->_raw_size)) + goto error_return; + + /* Look through the stabs symbols, work out the new string indices, + and identify N_BINCL symbols which can be eliminated. */ + + stroff = 0; + next_stroff = 0; + skip = 0; + + symend = stabbuf + stabsec->_raw_size; + for (sym = stabbuf, pstridx = secinfo->stridxs; + sym < symend; + sym += STABSIZE, ++pstridx) + { + int type; + const char *string; + + if (*pstridx != 0) + { + /* This symbol has already been handled by an N_BINCL pass. */ + continue; + } + + type = sym[TYPEOFF]; + + if (type == 0) + { + /* Special type 0 stabs indicate the offset to the next + string table. We only copy the very first one. */ + stroff = next_stroff; + next_stroff += bfd_get_32 (abfd, sym + 8); + if (! first) + { + *pstridx = (bfd_size_type) -1; + ++skip; + continue; + } + first = false; + } + + /* Store the string in the hash table, and record the index. */ + string = ((char *) stabstrbuf + + stroff + + bfd_get_32 (abfd, sym + STRDXOFF)); + *pstridx = _bfd_stringtab_add (sinfo->strings, string, true, true); + + /* An N_BINCL symbol indicates the start of the stabs entries + for a header file. We need to scan ahead to the next N_EINCL + symbol, ignoring nesting, adding up all the characters in the + symbol names, not including the file numbers in types (the + first number after an open parenthesis). */ + if (type == N_BINCL) + { + bfd_vma val; + int nest; + bfd_byte *incl_sym; + struct stab_link_includes_entry *incl_entry; + struct stab_link_includes_totals *t; + struct stab_excl_list *ne; + + val = 0; + nest = 0; + for (incl_sym = sym + STABSIZE; + incl_sym < symend; + incl_sym += STABSIZE) + { + int incl_type; + + incl_type = incl_sym[TYPEOFF]; + if (incl_type == 0) + break; + else if (incl_type == N_EINCL) + { + if (nest == 0) + break; + --nest; + } + else if (incl_type == N_BINCL) + ++nest; + else if (nest == 0) + { + const char *str; + + str = ((char *) stabstrbuf + + stroff + + bfd_get_32 (abfd, incl_sym + STRDXOFF)); + for (; *str != '\0'; str++) + { + val += *str; + if (*str == '(') + { + /* Skip the file number. */ + ++str; + while (isdigit ((unsigned char) *str)) + ++str; + --str; + } + } + } + } + + /* If we have already included a header file with the same + value, then replaced this one with an N_EXCL symbol. */ + incl_entry = stab_link_includes_lookup (&sinfo->includes, string, + true, true); + if (incl_entry == NULL) + goto error_return; + + for (t = incl_entry->totals; t != NULL; t = t->next) + if (t->total == val) + break; + + /* Record this symbol, so that we can set the value + correctly. */ + ne = (struct stab_excl_list *) bfd_alloc (abfd, sizeof *ne); + if (ne == NULL) + goto error_return; + ne->offset = sym - stabbuf; + ne->val = val; + ne->type = N_BINCL; + ne->next = secinfo->excls; + secinfo->excls = ne; + + if (t == NULL) + { + /* This is the first time we have seen this header file + with this set of stabs strings. */ + t = ((struct stab_link_includes_totals *) + bfd_hash_allocate (&sinfo->includes.root, sizeof *t)); + if (t == NULL) + goto error_return; + t->total = val; + t->next = incl_entry->totals; + incl_entry->totals = t; + } + else + { + bfd_size_type *incl_pstridx; + + /* We have seen this header file before. Tell the final + pass to change the type to N_EXCL. */ + ne->type = N_EXCL; + + /* Mark the skipped symbols. */ + + nest = 0; + for (incl_sym = sym + STABSIZE, incl_pstridx = pstridx + 1; + incl_sym < symend; + incl_sym += STABSIZE, ++incl_pstridx) + { + int incl_type; + + incl_type = incl_sym[TYPEOFF]; + + if (incl_type == N_EINCL) + { + if (nest == 0) + { + *incl_pstridx = (bfd_size_type) -1; + ++skip; + break; + } + --nest; + } + else if (incl_type == N_BINCL) + ++nest; + else if (nest == 0) + { + *incl_pstridx = (bfd_size_type) -1; + ++skip; + } + } + } + } + } + + free (stabbuf); + stabbuf = NULL; + free (stabstrbuf); + stabstrbuf = NULL; + + /* We need to set the section sizes such that the linker will + compute the output section sizes correctly. We set the .stab + size to not include the entries we don't want. We set + SEC_EXCLUDE for the .stabstr section, so that it will be dropped + from the link. We record the size of the strtab in the first + .stabstr section we saw, and make sure we don't set SEC_EXCLUDE + for that section. */ + stabsec->_cooked_size = (count - skip) * STABSIZE; + if (stabsec->_cooked_size == 0) + stabsec->flags |= SEC_EXCLUDE; + stabstrsec->flags |= SEC_EXCLUDE; + sinfo->stabstr->_cooked_size = _bfd_stringtab_size (sinfo->strings); + + /* Calculate the `cumulative_skips' array now that stabs have been + deleted for this section. */ + + if (skip != 0) + { + bfd_size_type i, offset; + bfd_size_type *pskips; + + secinfo->cumulative_skips = + (bfd_size_type *) bfd_alloc (abfd, count * sizeof (bfd_size_type)); + if (secinfo->cumulative_skips == NULL) + goto error_return; + + pskips = secinfo->cumulative_skips; + pstridx = secinfo->stridxs; + offset = 0; + + for (i = 0; i < count; i++, pskips++, pstridx++) + { + *pskips = offset; + if (*pstridx == (bfd_size_type) -1) + offset += STABSIZE; + } + + BFD_ASSERT (offset != 0); + } + + return true; + + error_return: + if (stabbuf != NULL) + free (stabbuf); + if (stabstrbuf != NULL) + free (stabstrbuf); + return false; +} + +/* Write out the stab section. This is called with the relocated + contents. */ + +boolean +_bfd_write_section_stabs (output_bfd, psinfo, stabsec, psecinfo, contents) + bfd *output_bfd; + PTR *psinfo; + asection *stabsec; + PTR *psecinfo; + bfd_byte *contents; +{ + struct stab_info *sinfo; + struct stab_section_info *secinfo; + struct stab_excl_list *e; + bfd_byte *sym, *tosym, *symend; + bfd_size_type *pstridx; + + sinfo = (struct stab_info *) *psinfo; + secinfo = (struct stab_section_info *) *psecinfo; + + if (secinfo == NULL) + return bfd_set_section_contents (output_bfd, stabsec->output_section, + contents, stabsec->output_offset, + stabsec->_raw_size); + + /* Handle each N_BINCL entry. */ + for (e = secinfo->excls; e != NULL; e = e->next) + { + bfd_byte *excl_sym; + + BFD_ASSERT (e->offset < stabsec->_raw_size); + excl_sym = contents + e->offset; + bfd_put_32 (output_bfd, e->val, excl_sym + VALOFF); + excl_sym[TYPEOFF] = e->type; + } + + /* 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; + + if (bfd_is_abs_section (sinfo->stabstr->output_section)) + { + /* The section was discarded from the link. */ + 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; +} |