/* ELF strtab with GC and suffix merging support. Copyright 2001, 2002 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" #include "libiberty.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; }; /* Routine to create an entry in a section merge hashtab. */ static struct bfd_hash_entry * elf_strtab_hash_newfunc (struct bfd_hash_entry *entry, struct bfd_hash_table *table, const char *string) { /* Allocate the structure if it has not already been allocated by a subclass. */ if (entry == NULL) entry = bfd_hash_allocate (table, sizeof (struct elf_strtab_hash_entry)); if (entry == NULL) return NULL; /* Call the allocation method of the superclass. */ entry = bfd_hash_newfunc (entry, table, string); if (entry) { /* Initialize the local fields. */ struct elf_strtab_hash_entry *ret; ret = (struct elf_strtab_hash_entry *) entry; ret->u.index = -1; ret->refcount = 0; ret->len = 0; } return entry; } /* Create a new hash table. */ struct elf_strtab_hash * _bfd_elf_strtab_init (void) { struct elf_strtab_hash *table; bfd_size_type amt = sizeof (struct elf_strtab_hash); table = 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 = 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 (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 (struct elf_strtab_hash *tab, const char *str, bfd_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 = 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 (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 (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 (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 (struct elf_strtab_hash *tab) { return tab->sec_size ? tab->sec_size : tab->size; } bfd_size_type _bfd_elf_strtab_offset (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; } bfd_boolean _bfd_elf_strtab_emit (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 (str, 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 (const void *a, const void *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 (const void *a, const void *b) { const struct elf_strtab_hash_entry *A = a; const struct elf_strtab_hash_entry *B = 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 (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 = 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_alloc (size * 4, NULL, last4_eq, NULL, calloc, free); 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; void **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 = *p; e->u.suffix = ent; e->len = 0; continue; } else *p = 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); } }