| /* ELF strtab with GC and suffix merging 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. */ |
| |
| #include "bfd.h" |
| #include "sysdep.h" |
| #include "libbfd.h" |
| #include "elf-bfd.h" |
| #include "hashtab.h" |
| |
| /* An entry in the strtab hash table. */ |
| |
| struct elf_strtab_hash_entry |
| { |
| struct bfd_hash_entry root; |
| /* Length of this entry. */ |
| unsigned int len; |
| unsigned int refcount; |
| union { |
| /* Index within the merged section. */ |
| bfd_size_type index; |
| /* Entry this is a suffix of (if len is 0). */ |
| struct elf_strtab_hash_entry *suffix; |
| struct elf_strtab_hash_entry *next; |
| } u; |
| }; |
| |
| /* The strtab hash table. */ |
| |
| struct elf_strtab_hash |
| { |
| struct bfd_hash_table table; |
| /* Next available index. */ |
| bfd_size_type size; |
| /* Number of array entries alloced. */ |
| bfd_size_type alloced; |
| /* Final strtab size. */ |
| bfd_size_type sec_size; |
| /* Array of pointers to strtab entries. */ |
| struct elf_strtab_hash_entry **array; |
| }; |
| |
| static struct bfd_hash_entry *elf_strtab_hash_newfunc |
| PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); |
| static int cmplengthentry PARAMS ((const PTR, const PTR)); |
| static int last4_eq PARAMS ((const PTR, const PTR)); |
| |
| /* Routine to create an entry in a section merge hashtab. */ |
| |
| static struct bfd_hash_entry * |
| elf_strtab_hash_newfunc (entry, table, string) |
| struct bfd_hash_entry *entry; |
| struct bfd_hash_table *table; |
| const char *string; |
| { |
| struct elf_strtab_hash_entry *ret = (struct elf_strtab_hash_entry *) entry; |
| |
| /* Allocate the structure if it has not already been allocated by a |
| subclass. */ |
| if (ret == (struct elf_strtab_hash_entry *) NULL) |
| ret = ((struct elf_strtab_hash_entry *) |
| bfd_hash_allocate (table, sizeof (struct elf_strtab_hash_entry))); |
| if (ret == (struct elf_strtab_hash_entry *) NULL) |
| return NULL; |
| |
| /* Call the allocation method of the superclass. */ |
| ret = ((struct elf_strtab_hash_entry *) |
| bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); |
| |
| if (ret) |
| { |
| /* Initialize the local fields. */ |
| ret->u.index = -1; |
| ret->refcount = 0; |
| ret->len = 0; |
| } |
| |
| return (struct bfd_hash_entry *)ret; |
| } |
| |
| /* Create a new hash table. */ |
| |
| struct elf_strtab_hash * |
| _bfd_elf_strtab_init () |
| { |
| struct elf_strtab_hash *table; |
| bfd_size_type amt = sizeof (struct elf_strtab_hash); |
| |
| table = (struct elf_strtab_hash *) bfd_malloc (amt); |
| if (table == NULL) |
| return NULL; |
| |
| if (! bfd_hash_table_init (&table->table, elf_strtab_hash_newfunc)) |
| { |
| free (table); |
| return NULL; |
| } |
| |
| table->sec_size = 0; |
| table->size = 1; |
| table->alloced = 64; |
| amt = sizeof (struct elf_strtab_hasn_entry *); |
| table->array = (struct elf_strtab_hash_entry **) |
| bfd_malloc (table->alloced * amt); |
| if (table->array == NULL) |
| { |
| free (table); |
| return NULL; |
| } |
| |
| table->array[0] = NULL; |
| |
| return table; |
| } |
| |
| /* Free a strtab. */ |
| |
| void |
| _bfd_elf_strtab_free (tab) |
| struct elf_strtab_hash *tab; |
| { |
| bfd_hash_table_free (&tab->table); |
| free (tab->array); |
| free (tab); |
| } |
| |
| /* Get the index of an entity in a hash table, adding it if it is not |
| already present. */ |
| |
| bfd_size_type |
| _bfd_elf_strtab_add (tab, str, copy) |
| struct elf_strtab_hash *tab; |
| const char *str; |
| boolean copy; |
| { |
| register struct elf_strtab_hash_entry *entry; |
| |
| /* We handle this specially, since we don't want to do refcounting |
| on it. */ |
| if (*str == '\0') |
| return 0; |
| |
| BFD_ASSERT (tab->sec_size == 0); |
| entry = (struct elf_strtab_hash_entry *) |
| bfd_hash_lookup (&tab->table, str, true, copy); |
| |
| if (entry == NULL) |
| return (bfd_size_type) -1; |
| |
| entry->refcount++; |
| if (entry->len == 0) |
| { |
| entry->len = strlen (str) + 1; |
| if (tab->size == tab->alloced) |
| { |
| bfd_size_type amt = sizeof (struct elf_strtab_hash_entry *); |
| tab->alloced *= 2; |
| tab->array = (struct elf_strtab_hash_entry **) |
| bfd_realloc (tab->array, tab->alloced * amt); |
| if (tab->array == NULL) |
| return (bfd_size_type) -1; |
| } |
| |
| entry->u.index = tab->size++; |
| tab->array[entry->u.index] = entry; |
| } |
| return entry->u.index; |
| } |
| |
| void |
| _bfd_elf_strtab_addref (tab, idx) |
| struct elf_strtab_hash *tab; |
| bfd_size_type idx; |
| { |
| if (idx == 0 || idx == (bfd_size_type) -1) |
| return; |
| BFD_ASSERT (tab->sec_size == 0); |
| BFD_ASSERT (idx < tab->size); |
| ++tab->array[idx]->refcount; |
| } |
| |
| void |
| _bfd_elf_strtab_delref (tab, idx) |
| struct elf_strtab_hash *tab; |
| bfd_size_type idx; |
| { |
| if (idx == 0 || idx == (bfd_size_type) -1) |
| return; |
| BFD_ASSERT (tab->sec_size == 0); |
| BFD_ASSERT (idx < tab->size); |
| BFD_ASSERT (tab->array[idx]->refcount > 0); |
| --tab->array[idx]->refcount; |
| } |
| |
| void |
| _bfd_elf_strtab_clear_all_refs (tab) |
| struct elf_strtab_hash *tab; |
| { |
| bfd_size_type idx; |
| |
| for (idx = 1; idx < tab->size; ++idx) |
| tab->array[idx]->refcount = 0; |
| } |
| |
| bfd_size_type |
| _bfd_elf_strtab_size (tab) |
| struct elf_strtab_hash *tab; |
| { |
| return tab->sec_size ? tab->sec_size : tab->size; |
| } |
| |
| bfd_size_type |
| _bfd_elf_strtab_offset (tab, idx) |
| struct elf_strtab_hash *tab; |
| bfd_size_type idx; |
| { |
| struct elf_strtab_hash_entry *entry; |
| |
| if (idx == 0) |
| return 0; |
| BFD_ASSERT (idx < tab->size); |
| BFD_ASSERT (tab->sec_size); |
| entry = tab->array[idx]; |
| BFD_ASSERT (entry->refcount > 0); |
| entry->refcount--; |
| return tab->array[idx]->u.index; |
| } |
| |
| boolean |
| _bfd_elf_strtab_emit (abfd, tab) |
| register bfd *abfd; |
| struct elf_strtab_hash *tab; |
| { |
| bfd_size_type off = 1, i; |
| |
| if (bfd_bwrite ("", 1, abfd) != 1) |
| return false; |
| |
| for (i = 1; i < tab->size; ++i) |
| { |
| register const char *str; |
| register size_t len; |
| |
| str = tab->array[i]->root.string; |
| len = tab->array[i]->len; |
| BFD_ASSERT (tab->array[i]->refcount == 0); |
| if (len == 0) |
| continue; |
| |
| if (bfd_bwrite ((PTR) str, (bfd_size_type) len, abfd) != len) |
| return false; |
| |
| off += len; |
| } |
| |
| BFD_ASSERT (off == tab->sec_size); |
| return true; |
| } |
| |
| /* Compare two elf_strtab_hash_entry structures. This is called via qsort. */ |
| |
| static int |
| cmplengthentry (a, b) |
| const PTR a; |
| const PTR b; |
| { |
| struct elf_strtab_hash_entry * A = *(struct elf_strtab_hash_entry **) a; |
| struct elf_strtab_hash_entry * B = *(struct elf_strtab_hash_entry **) b; |
| |
| if (A->len < B->len) |
| return 1; |
| else if (A->len > B->len) |
| return -1; |
| |
| return memcmp (A->root.string, B->root.string, A->len); |
| } |
| |
| static int |
| last4_eq (a, b) |
| const PTR a; |
| const PTR b; |
| { |
| struct elf_strtab_hash_entry * A = (struct elf_strtab_hash_entry *) a; |
| struct elf_strtab_hash_entry * B = (struct elf_strtab_hash_entry *) b; |
| |
| if (memcmp (A->root.string + A->len - 5, B->root.string + B->len - 5, 4) |
| != 0) |
| /* This was a hashtable collision. */ |
| return 0; |
| |
| if (A->len <= B->len) |
| /* B cannot be a suffix of A unless A is equal to B, which is guaranteed |
| not to be equal by the hash table. */ |
| return 0; |
| |
| return memcmp (A->root.string + (A->len - B->len), |
| B->root.string, B->len - 5) == 0; |
| } |
| |
| /* This function assigns final string table offsets for used strings, |
| merging strings matching suffixes of longer strings if possible. */ |
| |
| void |
| _bfd_elf_strtab_finalize (tab) |
| struct elf_strtab_hash *tab; |
| { |
| struct elf_strtab_hash_entry **array, **a, **end, *e; |
| htab_t last4tab = NULL; |
| bfd_size_type size, amt; |
| struct elf_strtab_hash_entry *last[256], **last_ptr[256]; |
| |
| /* GCC 2.91.66 (egcs-1.1.2) on i386 miscompiles this function when i is |
| a 64-bit bfd_size_type: a 64-bit target or --enable-64-bit-bfd. |
| Besides, indexing with a long long wouldn't give anything but extra |
| cycles. */ |
| size_t i; |
| |
| /* Now sort the strings by length, longest first. */ |
| array = NULL; |
| amt = tab->size * sizeof (struct elf_strtab_hash_entry *); |
| array = (struct elf_strtab_hash_entry **) bfd_malloc (amt); |
| if (array == NULL) |
| goto alloc_failure; |
| |
| memset (last, 0, sizeof (last)); |
| for (i = 0; i < 256; ++i) |
| last_ptr[i] = &last[i]; |
| for (i = 1, a = array; i < tab->size; ++i) |
| if (tab->array[i]->refcount) |
| *a++ = tab->array[i]; |
| else |
| tab->array[i]->len = 0; |
| |
| size = a - array; |
| |
| qsort (array, size, sizeof (struct elf_strtab_hash_entry *), cmplengthentry); |
| |
| last4tab = htab_create (size * 4, NULL, last4_eq, NULL); |
| if (last4tab == NULL) |
| goto alloc_failure; |
| |
| /* Now insert the strings into hash tables (strings with last 4 characters |
| and strings with last character equal), look for longer strings which |
| we're suffix of. */ |
| for (a = array, end = array + size; a < end; a++) |
| { |
| register hashval_t hash; |
| unsigned int c; |
| unsigned int j; |
| const unsigned char *s; |
| PTR *p; |
| |
| e = *a; |
| if (e->len > 4) |
| { |
| s = e->root.string + e->len - 1; |
| hash = 0; |
| for (j = 0; j < 4; j++) |
| { |
| c = *--s; |
| hash += c + (c << 17); |
| hash ^= hash >> 2; |
| } |
| p = htab_find_slot_with_hash (last4tab, e, hash, INSERT); |
| if (p == NULL) |
| goto alloc_failure; |
| if (*p) |
| { |
| struct elf_strtab_hash_entry *ent; |
| |
| ent = (struct elf_strtab_hash_entry *) *p; |
| e->u.suffix = ent; |
| e->len = 0; |
| continue; |
| } |
| else |
| *p = (PTR) e; |
| } |
| else |
| { |
| struct elf_strtab_hash_entry *tem; |
| |
| c = e->root.string[e->len - 2] & 0xff; |
| |
| for (tem = last[c]; tem; tem = tem->u.next) |
| if (tem->len > e->len |
| && memcmp (tem->root.string + (tem->len - e->len), |
| e->root.string, e->len - 1) == 0) |
| break; |
| if (tem) |
| { |
| e->u.suffix = tem; |
| e->len = 0; |
| continue; |
| } |
| } |
| |
| c = e->root.string[e->len - 2] & 0xff; |
| /* Put longest strings first. */ |
| *last_ptr[c] = e; |
| last_ptr[c] = &e->u.next; |
| e->u.next = NULL; |
| } |
| |
| alloc_failure: |
| if (array) |
| free (array); |
| if (last4tab) |
| htab_delete (last4tab); |
| |
| /* Now assign positions to the strings we want to keep. */ |
| size = 1; |
| for (i = 1; i < tab->size; ++i) |
| { |
| e = tab->array[i]; |
| if (e->refcount && e->len) |
| { |
| e->u.index = size; |
| size += e->len; |
| } |
| } |
| |
| tab->sec_size = size; |
| |
| /* And now adjust the rest. */ |
| for (i = 1; i < tab->size; ++i) |
| { |
| e = tab->array[i]; |
| if (e->refcount && ! e->len) |
| e->u.index = e->u.suffix->u.index |
| + (e->u.suffix->len - strlen (e->root.string) - 1); |
| } |
| } |