summaryrefslogtreecommitdiff
path: root/bfd/merge.c
diff options
context:
space:
mode:
authorJakub Jelinek <jakub@redhat.com>2001-04-13 00:34:36 +0000
committerJakub Jelinek <jakub@redhat.com>2001-04-13 00:34:36 +0000
commitc0c2cff88bb107c2ce9c644ccc7dfbfc520c2e40 (patch)
treed0b659614ce2fccd3df4e66875b0bd2572abfb4e /bfd/merge.c
parent6bc21d1032df5f0cefe56b4c58d3f76ea0159791 (diff)
downloadgdb-c0c2cff88bb107c2ce9c644ccc7dfbfc520c2e40.tar.gz
bfd/
* libbfd-in.h (_bfd_merge_section): New. (_bfd_write_merged_section): New. (_bfd_merged_section_offset): New. * libbfd.h: Rebuilt. * linker.c (_bfd_generic_link_output_symbols): Handle discard_sec_merge. * aoutx.h (aout_link_write_symbols): Likewise. * pdp11.c (aout_link_write_symbols): Likewise. * elflink.h (elf_link_add_object_symbols): Call _bfd_merge_section. (elf_bfd_final_link): Adjust global symbols pointing into SEC_MERGE sections. (elf_link_sec_merge_syms): New. (elf_link_input_bfd): Call _bfd_merged_section_offset and _bfd_write_merged_section. Handle discard_sec_merge. * elf-bfd.h (struct elf_link_hash_table): Add merge_info field. (struct bfd_elf_section_data): Likewise. * elf.c (_bfd_elf_make_section_from_shdr): Set SEC_MERGE and SEC_STRINGS section flags and entsize from their ELF counterparts. (_bfd_elf_link_hash_table_init): Initialize merge_info. (elf_fake_sections): Set SHF_MERGE, SHF_STRINGS and sh_entsize from their BFD counterparts. * merge.c: New file. * Makefile.am: Add strtab.lo. * Makefile.in: Rebuilt. include/ * bfdlink.h (bfd_link_discard): Add discard_sec_merge. gas/ * config/obj-elf.c (obj_elf_change_section): Add entsize argument, handle SHF_MERGE and SHF_STRINGS. (obj_elf_parse_section_letters): Set SHF_MERGE and SHF_STRINGS. (obj_elf_section): Allow additional argument specifying entity size. * write.c (adjust_reloc_syms): Keep relocations against local symbols in SEC_MERGE sections. ld/ * ldmain.c (main): Default to discard_sec_merge. * lexsup.c (OPTION_DISCARD_NONE): Define. (ld_options): Add --discard-none. (parse_args): Handle OPTION_DISCARD_NONE. * ldlang.c (wild_doit): SEC_MERGE should be set in the output section only if SEC_MERGE and SEC_STRINGS flags and entsize of all its input sections match.
Diffstat (limited to 'bfd/merge.c')
-rw-r--r--bfd/merge.c606
1 files changed, 606 insertions, 0 deletions
diff --git a/bfd/merge.c b/bfd/merge.c
new file mode 100644
index 00000000000..ace069eca0d
--- /dev/null
+++ b/bfd/merge.c
@@ -0,0 +1,606 @@
+/* SEC_MERGE support.
+ Copyright 2001 Free Software Foundation, Inc.
+ Written by Jakub Jelinek <jakub@redhat.com>.
+
+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 merging duplicate entities within sections,
+ as used in ELF SHF_MERGE. */
+
+#include "bfd.h"
+#include "sysdep.h"
+#include "libbfd.h"
+
+#include <ctype.h>
+
+/* An entry in the section merge hash table. */
+
+struct sec_merge_hash_entry
+{
+ struct bfd_hash_entry root;
+ /* Length of this entry. */
+ unsigned int len;
+ /* Index within the merged section. */
+ bfd_size_type index;
+ /* Which section is it in. */
+ asection *sec;
+ /* Next entity in the hash table. */
+ struct sec_merge_hash_entry *next;
+};
+
+/* The section merge hash table. */
+
+struct sec_merge_hash
+{
+ struct bfd_hash_table table;
+ /* Next available index. */
+ bfd_size_type size;
+ /* First entity in the SEC_MERGE sections of this type. */
+ struct sec_merge_hash_entry *first;
+ /* Last entity in the SEC_MERGE sections of this type. */
+ struct sec_merge_hash_entry *last;
+ /* Entity size. */
+ unsigned int entsize;
+ /* Start of each string needs to be aligned to 1 << alignment_power
+ octets. */
+ unsigned int alignment_power;
+ /* Are entries fixed size or zero terminated strings? */
+ boolean strings;
+};
+
+struct sec_merge_info
+{
+ /* Chain of sec_merge_infos. */
+ struct sec_merge_info *next;
+ /* A hash table used to hold section content. */
+ struct sec_merge_hash *htab;
+ /* The last section attempted for merge. */
+ asection *last;
+};
+
+struct sec_merge_sec_info
+{
+ /* A hash table used to hold section content. */
+ struct sec_merge_hash *htab;
+ /* First string in this section. */
+ struct sec_merge_hash_entry *first;
+ /* Original section content. */
+ unsigned char contents[1];
+};
+
+static struct bfd_hash_entry *sec_merge_hash_newfunc
+ PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
+static struct sec_merge_hash_entry *sec_merge_hash_lookup
+ PARAMS ((struct sec_merge_hash *, const char *, boolean));
+static struct sec_merge_hash *sec_merge_init
+ PARAMS ((unsigned int, unsigned int, boolean));
+static struct sec_merge_hash_entry *sec_merge_add
+ PARAMS ((struct sec_merge_hash *, const char *));
+static boolean sec_merge_emit
+ PARAMS ((bfd *, struct sec_merge_hash *, struct sec_merge_hash_entry *));
+
+/* Routine to create an entry in a section merge hashtab. */
+
+static struct bfd_hash_entry *
+sec_merge_hash_newfunc (entry, table, string)
+ struct bfd_hash_entry *entry;
+ struct bfd_hash_table *table;
+ const char *string;
+{
+ struct sec_merge_hash_entry *ret = (struct sec_merge_hash_entry *) entry;
+
+ /* Allocate the structure if it has not already been allocated by a
+ subclass. */
+ if (ret == (struct sec_merge_hash_entry *) NULL)
+ ret = ((struct sec_merge_hash_entry *)
+ bfd_hash_allocate (table, sizeof (struct sec_merge_hash_entry)));
+ if (ret == (struct sec_merge_hash_entry *) NULL)
+ return NULL;
+
+ /* Call the allocation method of the superclass. */
+ ret = ((struct sec_merge_hash_entry *)
+ bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
+
+ if (ret)
+ {
+ /* Initialize the local fields. */
+ ret->index = (bfd_size_type) -1;
+ ret->sec = NULL;
+ ret->next = NULL;
+ }
+
+ return (struct bfd_hash_entry *)ret;
+}
+
+/* Look up an entry in a section merge hash table. */
+
+static struct sec_merge_hash_entry *
+sec_merge_hash_lookup (table, string, create)
+ struct sec_merge_hash *table;
+ const char *string;
+ boolean create;
+{
+ register const unsigned char *s;
+ register unsigned long hash;
+ register unsigned int c;
+ struct sec_merge_hash_entry *hashp;
+ unsigned int len, i;
+ unsigned int index;
+
+ hash = 0;
+ len = 0;
+ s = (const unsigned char *) string;
+ if (table->strings)
+ {
+ if (table->entsize == 1)
+ {
+ while ((c = *s++) != '\0')
+ {
+ hash += c + (c << 17);
+ hash ^= hash >> 2;
+ ++len;
+ }
+ hash += len + (len << 17);
+ }
+ else
+ {
+ for (;;)
+ {
+ for (i = 0; i < table->entsize; ++i)
+ if (s[i] != '\0')
+ break;
+ if (i == table->entsize)
+ break;
+ for (i = 0; i < table->entsize; ++i)
+ {
+ c = *s++;
+ hash += c + (c << 17);
+ hash ^= hash >> 2;
+ }
+ ++len;
+ }
+ hash += len + (len << 17);
+ len *= table->entsize;
+ }
+ hash ^= hash >> 2;
+ len += table->entsize;
+ }
+ else
+ {
+ for (i = 0; i < table->entsize; ++i)
+ {
+ c = *s++;
+ hash += c + (c << 17);
+ hash ^= hash >> 2;
+ }
+ len = table->entsize;
+ }
+
+ index = hash % table->table.size;
+ for (hashp = (struct sec_merge_hash_entry *) table->table.table[index];
+ hashp != (struct sec_merge_hash_entry *) NULL;
+ hashp = (struct sec_merge_hash_entry *) hashp->next)
+ {
+ if (hashp->root.hash == hash
+ && len == hashp->len
+ && memcmp (hashp->root.string, string, len) == 0)
+ return hashp;
+ }
+
+ if (! create)
+ return (struct sec_merge_hash_entry *) NULL;
+
+ hashp = (struct sec_merge_hash_entry *)
+ sec_merge_hash_newfunc ((struct bfd_hash_entry *) NULL,
+ (struct bfd_hash_table *) table, string);
+ if (hashp == (struct sec_merge_hash_entry *) NULL)
+ return (struct sec_merge_hash_entry *) NULL;
+ hashp->root.string = string;
+ hashp->root.hash = hash;
+ hashp->len = len;
+ hashp->root.next = table->table.table[index];
+ table->table.table[index] = (struct bfd_hash_entry *) hashp;
+
+ return hashp;
+}
+
+/* Create a new hash table. */
+
+static struct sec_merge_hash *
+sec_merge_init (alignment_power, entsize, strings)
+ unsigned int alignment_power, entsize;
+ boolean strings;
+{
+ struct sec_merge_hash *table;
+
+ table = ((struct sec_merge_hash *)
+ bfd_malloc (sizeof (struct sec_merge_hash)));
+ if (table == NULL)
+ return NULL;
+
+ if (! bfd_hash_table_init (&table->table, sec_merge_hash_newfunc))
+ {
+ free (table);
+ return NULL;
+ }
+
+ table->size = 0;
+ table->first = NULL;
+ table->last = NULL;
+ table->alignment_power = alignment_power;
+ table->entsize = entsize;
+ table->strings = strings;
+
+ return table;
+}
+
+/* Get the index of an entity in a hash table, adding it if it is not
+ already present. */
+
+static struct sec_merge_hash_entry *
+sec_merge_add (tab, str)
+ struct sec_merge_hash *tab;
+ const char *str;
+{
+ register struct sec_merge_hash_entry *entry;
+
+ entry = sec_merge_hash_lookup (tab, str, true);
+ if (entry == NULL)
+ return NULL;
+
+ if (entry->index == (bfd_size_type) -1)
+ {
+ entry->index = tab->size;
+ tab->size += entry->len;
+ tab->size = align_power (tab->size, tab->alignment_power);
+ if (tab->first == NULL)
+ tab->first = entry;
+ else
+ tab->last->next = entry;
+ tab->last = entry;
+ }
+
+ return entry;
+}
+
+static boolean
+sec_merge_emit (abfd, tab, entry)
+ register bfd *abfd;
+ struct sec_merge_hash *tab;
+ struct sec_merge_hash_entry *entry;
+{
+ asection *sec = entry->sec;
+ char *pad = "";
+
+ if (tab->alignment_power)
+ pad = bfd_zmalloc (1 << tab->alignment_power);
+
+ for (; entry != NULL && entry->sec == sec; entry = entry->next)
+ {
+ register const char *str;
+ register size_t len;
+
+ str = entry->root.string;
+ len = entry->len;
+
+ if (bfd_write ((PTR) str, 1, len, abfd) != len)
+ break;
+
+ if (tab->alignment_power)
+ {
+ len &= (1 << tab->alignment_power) - 1;
+ if (len && bfd_write ((PTR) pad, 1,
+ (1 << tab->alignment_power) - len,
+ abfd) != (1 << tab->alignment_power) - len)
+ break;
+ }
+ }
+
+ if (tab->alignment_power)
+ free (pad);
+
+ return entry == NULL || entry->sec != sec;
+}
+
+/* This function is called for each input file from the add_symbols
+ pass of the linker. */
+
+boolean
+_bfd_merge_section (abfd, psinfo, sec, psecinfo)
+ bfd *abfd;
+ PTR *psinfo;
+ asection *sec;
+ PTR *psecinfo;
+{
+ boolean first, nul;
+ struct sec_merge_info *sinfo;
+ struct sec_merge_sec_info *secinfo;
+ unsigned char *p, *end;
+ bfd_vma mask;
+ unsigned int align;
+ unsigned int i;
+
+ if (sec->_raw_size == 0
+ || (sec->flags & SEC_MERGE) == 0
+ || sec->entsize == 0)
+ return true;
+
+ if ((sec->flags & SEC_RELOC) != 0)
+ {
+ /* We aren't prepared to handle relocations in merged sections. */
+ return true;
+ }
+
+ if (sec->output_section != NULL
+ && bfd_is_abs_section (sec->output_section))
+ {
+ /* The section is being discarded from the link, so we should
+ just ignore it. */
+ return true;
+ }
+
+ align = bfd_get_section_alignment (abfd, sec);
+ if ((sec->flags & SEC_STRINGS)
+ && ((sec->entsize < (unsigned int)(1 << align)
+ && (sec->entsize & (sec->entsize - 1)))
+ || (sec->entsize > (unsigned int)(1 << align)
+ && (sec->entsize & ((1 << align) - 1)))))
+ {
+ /* Sanity check. If string character size is smaller than
+ alignment, then we require character size to be a power
+ of 2, otherwise character size must be integer multiple
+ of alignment. */
+ return true;
+ }
+
+ first = false;
+
+ for (sinfo = (struct sec_merge_info *) *psinfo; sinfo; sinfo = sinfo->next)
+ if (! ((sinfo->last->flags ^ sec->flags) & (SEC_MERGE | SEC_STRINGS))
+ && sinfo->last->entsize == sec->entsize
+ && ! strcmp (sinfo->last->name, sec->name)
+ && bfd_get_section_alignment (abfd, sinfo->last) == align)
+ break;
+
+ if (sinfo == NULL)
+ {
+ /* Initialize the information we need to keep track of. */
+ first = true;
+ sinfo = (struct sec_merge_info *)
+ bfd_alloc (abfd, sizeof (struct sec_merge_info));
+ if (sinfo == NULL)
+ goto error_return;
+ sinfo->next = (struct sec_merge_info *) *psinfo;
+ *psinfo = (PTR) sinfo;
+ sinfo->htab =
+ sec_merge_init ((sec->flags & SEC_STRINGS) ? align : 0,
+ sec->entsize, (sec->flags & SEC_STRINGS));
+ if (sinfo->htab == NULL)
+ goto error_return;
+ }
+
+ /* Read the section from abfd. */
+
+ *psecinfo = bfd_alloc (abfd, sizeof (struct sec_merge_sec_info)
+ + sec->_raw_size - 1);
+ if (*psecinfo == NULL)
+ goto error_return;
+
+ secinfo = (struct sec_merge_sec_info *)*psecinfo;
+ secinfo->htab = sinfo->htab;
+ sinfo->htab->size = 0;
+ secinfo->first = NULL;
+
+ if (! bfd_get_section_contents (abfd, sec, secinfo->contents, 0,
+ sec->_raw_size))
+ goto error_return;
+
+ end = secinfo->contents + sec->_raw_size;
+ nul = false;
+ mask = ((bfd_vma)1 << sinfo->htab->alignment_power) - 1;
+ if (sec->flags & SEC_STRINGS)
+ {
+ for (p = secinfo->contents; p < end;)
+ {
+ struct sec_merge_hash_entry *entry;
+
+ entry = sec_merge_add (sinfo->htab, p);
+ if (entry->sec == NULL)
+ {
+ if (secinfo->first == NULL)
+ secinfo->first = entry;
+ entry->sec = sec;
+ }
+ p += entry->len;
+ if (sec->entsize == 1)
+ {
+ while (p < end && *p == 0)
+ {
+ if (!nul && !((p - secinfo->contents) & mask))
+ {
+ nul = true;
+ entry = sec_merge_add (sinfo->htab, "");
+ if (entry->sec == NULL)
+ {
+ if (secinfo->first == NULL)
+ secinfo->first = entry;
+ entry->sec = sec;
+ }
+ }
+ p++;
+ }
+ }
+ else
+ {
+ while (p < end)
+ {
+ for (i = 0; i < sec->entsize; i++)
+ if (p[i] != '\0')
+ break;
+ if (i != sec->entsize)
+ break;
+ if (!nul && !((p - secinfo->contents) & mask))
+ {
+ nul = true;
+ entry = sec_merge_add (sinfo->htab, p);
+ if (entry->sec == NULL)
+ {
+ if (secinfo->first == NULL)
+ secinfo->first = entry;
+ entry->sec = sec;
+ }
+ }
+ p += sec->entsize;
+ }
+ }
+ }
+ }
+ else
+ {
+ for (p = secinfo->contents; p < end; p += sec->entsize)
+ {
+ struct sec_merge_hash_entry *entry;
+
+ entry = sec_merge_add (sinfo->htab, p);
+ if (entry->sec == NULL)
+ {
+ if (secinfo->first == NULL)
+ secinfo->first = entry;
+ entry->sec = sec;
+ }
+ }
+ }
+
+ sec->_cooked_size = sinfo->htab->size;
+ if (!sec->_cooked_size)
+ sec->flags |= SEC_EXCLUDE;
+ sinfo->last = sec;
+ return true;
+
+ error_return:
+ if (*psecinfo != NULL)
+ free (*psecinfo);
+ *psecinfo = NULL;
+ return false;
+}
+
+/* Write out the merged section. */
+
+boolean
+_bfd_write_merged_section (output_bfd, sec, psecinfo)
+ bfd *output_bfd;
+ asection *sec;
+ PTR psecinfo;
+{
+ struct sec_merge_sec_info *secinfo;
+
+ secinfo = (struct sec_merge_sec_info *) psecinfo;
+
+ if (!secinfo->first)
+ return true;
+
+ if (bfd_seek (output_bfd,
+ (sec->output_section->filepos + sec->output_offset),
+ SEEK_SET) != 0)
+ return false;
+
+ if (! sec_merge_emit (output_bfd, secinfo->htab, secinfo->first))
+ return false;
+
+ return true;
+}
+
+/* Adjust an address in the SEC_MERGE section. Given OFFSET within
+ *PSEC, this returns the new offset in the adjusted SEC_MERGE
+ section and writes the new section back into *PSEC. */
+
+bfd_vma
+_bfd_merged_section_offset (output_bfd, psec, psecinfo, offset, addend)
+ bfd *output_bfd ATTRIBUTE_UNUSED;
+ asection **psec;
+ PTR psecinfo;
+ bfd_vma offset, addend;
+{
+ struct sec_merge_sec_info *secinfo;
+ struct sec_merge_hash_entry *entry;
+ unsigned char *p;
+ asection *sec = *psec;
+
+ secinfo = (struct sec_merge_sec_info *) psecinfo;
+
+ if (offset + addend >= sec->_raw_size)
+ {
+ if (offset + addend > sec->_raw_size)
+ (*_bfd_error_handler) (_("%s: access beyond end of merged section (%ld + %ld)"),
+ bfd_get_filename (sec->owner), (long)offset,
+ (long) addend);
+ return (secinfo->first ? sec->_cooked_size : 0);
+ }
+
+ if (secinfo->htab->strings)
+ {
+ if (sec->entsize == 1)
+ {
+ p = secinfo->contents + offset + addend - 1;
+ while (*p && p >= secinfo->contents)
+ --p;
+ ++p;
+ }
+ else
+ {
+ p = secinfo->contents
+ + ((offset + addend) / sec->entsize) * sec->entsize;
+ p -= sec->entsize;
+ while (p >= secinfo->contents)
+ {
+ unsigned int i;
+
+ for (i = 0; i < sec->entsize; ++i)
+ if (p[i] != '\0')
+ break;
+ if (i == sec->entsize)
+ break;
+ p -= sec->entsize;
+ }
+ p += sec->entsize;
+ }
+ }
+ else
+ {
+ p = secinfo->contents
+ + ((offset + addend) / sec->entsize) * sec->entsize;
+ }
+ entry = sec_merge_hash_lookup (secinfo->htab, p, false);
+ if (!entry)
+ {
+ if (! secinfo->htab->strings)
+ abort ();
+ /* This should only happen if somebody points into the padding
+ after a NUL character but before next entity. */
+ if (*p)
+ abort ();
+ if (! secinfo->htab->first)
+ abort ();
+ entry = secinfo->htab->first;
+ p = secinfo->contents
+ + ((offset + addend) / sec->entsize + 1) * sec->entsize
+ - entry->len;
+ }
+
+ *psec = entry->sec;
+ return entry->index + (secinfo->contents + offset - p);
+}