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Diffstat (limited to 'binutils-2.17/bfd/hash.c')
| -rw-r--r-- | binutils-2.17/bfd/hash.c | 736 |
1 files changed, 0 insertions, 736 deletions
diff --git a/binutils-2.17/bfd/hash.c b/binutils-2.17/bfd/hash.c deleted file mode 100644 index ce9ba5c6..00000000 --- a/binutils-2.17/bfd/hash.c +++ /dev/null @@ -1,736 +0,0 @@ -/* hash.c -- hash table routines for BFD - Copyright 1993, 1994, 1995, 1997, 1999, 2001, 2002, 2003, 2004, 2005, - 2006 Free Software Foundation, Inc. - Written by Steve Chamberlain <sac@cygnus.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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ - -#include "bfd.h" -#include "sysdep.h" -#include "libbfd.h" -#include "objalloc.h" -#include "libiberty.h" - -/* -SECTION - Hash Tables - -@cindex Hash tables - BFD provides a simple set of hash table functions. Routines - are provided to initialize a hash table, to free a hash table, - to look up a string in a hash table and optionally create an - entry for it, and to traverse a hash table. There is - currently no routine to delete an string from a hash table. - - The basic hash table does not permit any data to be stored - with a string. However, a hash table is designed to present a - base class from which other types of hash tables may be - derived. These derived types may store additional information - with the string. Hash tables were implemented in this way, - rather than simply providing a data pointer in a hash table - entry, because they were designed for use by the linker back - ends. The linker may create thousands of hash table entries, - and the overhead of allocating private data and storing and - following pointers becomes noticeable. - - The basic hash table code is in <<hash.c>>. - -@menu -@* Creating and Freeing a Hash Table:: -@* Looking Up or Entering a String:: -@* Traversing a Hash Table:: -@* Deriving a New Hash Table Type:: -@end menu - -INODE -Creating and Freeing a Hash Table, Looking Up or Entering a String, Hash Tables, Hash Tables -SUBSECTION - Creating and freeing a hash table - -@findex bfd_hash_table_init -@findex bfd_hash_table_init_n - To create a hash table, create an instance of a <<struct - bfd_hash_table>> (defined in <<bfd.h>>) and call - <<bfd_hash_table_init>> (if you know approximately how many - entries you will need, the function <<bfd_hash_table_init_n>>, - which takes a @var{size} argument, may be used). - <<bfd_hash_table_init>> returns <<FALSE>> if some sort of - error occurs. - -@findex bfd_hash_newfunc - The function <<bfd_hash_table_init>> take as an argument a - function to use to create new entries. For a basic hash - table, use the function <<bfd_hash_newfunc>>. @xref{Deriving - a New Hash Table Type}, for why you would want to use a - different value for this argument. - -@findex bfd_hash_allocate - <<bfd_hash_table_init>> will create an objalloc which will be - used to allocate new entries. You may allocate memory on this - objalloc using <<bfd_hash_allocate>>. - -@findex bfd_hash_table_free - Use <<bfd_hash_table_free>> to free up all the memory that has - been allocated for a hash table. This will not free up the - <<struct bfd_hash_table>> itself, which you must provide. - -@findex bfd_hash_set_default_size - Use <<bfd_hash_set_default_size>> to set the default size of - hash table to use. - -INODE -Looking Up or Entering a String, Traversing a Hash Table, Creating and Freeing a Hash Table, Hash Tables -SUBSECTION - Looking up or entering a string - -@findex bfd_hash_lookup - The function <<bfd_hash_lookup>> is used both to look up a - string in the hash table and to create a new entry. - - If the @var{create} argument is <<FALSE>>, <<bfd_hash_lookup>> - will look up a string. If the string is found, it will - returns a pointer to a <<struct bfd_hash_entry>>. If the - string is not found in the table <<bfd_hash_lookup>> will - return <<NULL>>. You should not modify any of the fields in - the returns <<struct bfd_hash_entry>>. - - If the @var{create} argument is <<TRUE>>, the string will be - entered into the hash table if it is not already there. - Either way a pointer to a <<struct bfd_hash_entry>> will be - returned, either to the existing structure or to a newly - created one. In this case, a <<NULL>> return means that an - error occurred. - - If the @var{create} argument is <<TRUE>>, and a new entry is - created, the @var{copy} argument is used to decide whether to - copy the string onto the hash table objalloc or not. If - @var{copy} is passed as <<FALSE>>, you must be careful not to - deallocate or modify the string as long as the hash table - exists. - -INODE -Traversing a Hash Table, Deriving a New Hash Table Type, Looking Up or Entering a String, Hash Tables -SUBSECTION - Traversing a hash table - -@findex bfd_hash_traverse - The function <<bfd_hash_traverse>> may be used to traverse a - hash table, calling a function on each element. The traversal - is done in a random order. - - <<bfd_hash_traverse>> takes as arguments a function and a - generic <<void *>> pointer. The function is called with a - hash table entry (a <<struct bfd_hash_entry *>>) and the - generic pointer passed to <<bfd_hash_traverse>>. The function - must return a <<boolean>> value, which indicates whether to - continue traversing the hash table. If the function returns - <<FALSE>>, <<bfd_hash_traverse>> will stop the traversal and - return immediately. - -INODE -Deriving a New Hash Table Type, , Traversing a Hash Table, Hash Tables -SUBSECTION - Deriving a new hash table type - - Many uses of hash tables want to store additional information - which each entry in the hash table. Some also find it - convenient to store additional information with the hash table - itself. This may be done using a derived hash table. - - Since C is not an object oriented language, creating a derived - hash table requires sticking together some boilerplate - routines with a few differences specific to the type of hash - table you want to create. - - An example of a derived hash table is the linker hash table. - The structures for this are defined in <<bfdlink.h>>. The - functions are in <<linker.c>>. - - You may also derive a hash table from an already derived hash - table. For example, the a.out linker backend code uses a hash - table derived from the linker hash table. - -@menu -@* Define the Derived Structures:: -@* Write the Derived Creation Routine:: -@* Write Other Derived Routines:: -@end menu - -INODE -Define the Derived Structures, Write the Derived Creation Routine, Deriving a New Hash Table Type, Deriving a New Hash Table Type -SUBSUBSECTION - Define the derived structures - - You must define a structure for an entry in the hash table, - and a structure for the hash table itself. - - The first field in the structure for an entry in the hash - table must be of the type used for an entry in the hash table - you are deriving from. If you are deriving from a basic hash - table this is <<struct bfd_hash_entry>>, which is defined in - <<bfd.h>>. The first field in the structure for the hash - table itself must be of the type of the hash table you are - deriving from itself. If you are deriving from a basic hash - table, this is <<struct bfd_hash_table>>. - - For example, the linker hash table defines <<struct - bfd_link_hash_entry>> (in <<bfdlink.h>>). The first field, - <<root>>, is of type <<struct bfd_hash_entry>>. Similarly, - the first field in <<struct bfd_link_hash_table>>, <<table>>, - is of type <<struct bfd_hash_table>>. - -INODE -Write the Derived Creation Routine, Write Other Derived Routines, Define the Derived Structures, Deriving a New Hash Table Type -SUBSUBSECTION - Write the derived creation routine - - You must write a routine which will create and initialize an - entry in the hash table. This routine is passed as the - function argument to <<bfd_hash_table_init>>. - - In order to permit other hash tables to be derived from the - hash table you are creating, this routine must be written in a - standard way. - - The first argument to the creation routine is a pointer to a - hash table entry. This may be <<NULL>>, in which case the - routine should allocate the right amount of space. Otherwise - the space has already been allocated by a hash table type - derived from this one. - - After allocating space, the creation routine must call the - creation routine of the hash table type it is derived from, - passing in a pointer to the space it just allocated. This - will initialize any fields used by the base hash table. - - Finally the creation routine must initialize any local fields - for the new hash table type. - - Here is a boilerplate example of a creation routine. - @var{function_name} is the name of the routine. - @var{entry_type} is the type of an entry in the hash table you - are creating. @var{base_newfunc} is the name of the creation - routine of the hash table type your hash table is derived - from. - -EXAMPLE - -.struct bfd_hash_entry * -.@var{function_name} (struct bfd_hash_entry *entry, -. struct bfd_hash_table *table, -. const char *string) -.{ -. struct @var{entry_type} *ret = (@var{entry_type} *) entry; -. -. {* Allocate the structure if it has not already been allocated by a -. derived class. *} -. if (ret == NULL) -. { -. ret = bfd_hash_allocate (table, sizeof (* ret)); -. if (ret == NULL) -. return NULL; -. } -. -. {* Call the allocation method of the base class. *} -. ret = ((@var{entry_type} *) -. @var{base_newfunc} ((struct bfd_hash_entry *) ret, table, string)); -. -. {* Initialize the local fields here. *} -. -. return (struct bfd_hash_entry *) ret; -.} - -DESCRIPTION - The creation routine for the linker hash table, which is in - <<linker.c>>, looks just like this example. - @var{function_name} is <<_bfd_link_hash_newfunc>>. - @var{entry_type} is <<struct bfd_link_hash_entry>>. - @var{base_newfunc} is <<bfd_hash_newfunc>>, the creation - routine for a basic hash table. - - <<_bfd_link_hash_newfunc>> also initializes the local fields - in a linker hash table entry: <<type>>, <<written>> and - <<next>>. - -INODE -Write Other Derived Routines, , Write the Derived Creation Routine, Deriving a New Hash Table Type -SUBSUBSECTION - Write other derived routines - - You will want to write other routines for your new hash table, - as well. - - You will want an initialization routine which calls the - initialization routine of the hash table you are deriving from - and initializes any other local fields. For the linker hash - table, this is <<_bfd_link_hash_table_init>> in <<linker.c>>. - - You will want a lookup routine which calls the lookup routine - of the hash table you are deriving from and casts the result. - The linker hash table uses <<bfd_link_hash_lookup>> in - <<linker.c>> (this actually takes an additional argument which - it uses to decide how to return the looked up value). - - You may want a traversal routine. This should just call the - traversal routine of the hash table you are deriving from with - appropriate casts. The linker hash table uses - <<bfd_link_hash_traverse>> in <<linker.c>>. - - These routines may simply be defined as macros. For example, - the a.out backend linker hash table, which is derived from the - linker hash table, uses macros for the lookup and traversal - routines. These are <<aout_link_hash_lookup>> and - <<aout_link_hash_traverse>> in aoutx.h. -*/ - -/* The default number of entries to use when creating a hash table. */ -#define DEFAULT_SIZE 4051 -static size_t bfd_default_hash_table_size = DEFAULT_SIZE; - -/* Create a new hash table, given a number of entries. */ - -bfd_boolean -bfd_hash_table_init_n (struct bfd_hash_table *table, - struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, - struct bfd_hash_table *, - const char *), - unsigned int entsize, - unsigned int size) -{ - unsigned int alloc; - - alloc = size * sizeof (struct bfd_hash_entry *); - - table->memory = (void *) objalloc_create (); - if (table->memory == NULL) - { - bfd_set_error (bfd_error_no_memory); - return FALSE; - } - table->table = objalloc_alloc ((struct objalloc *) table->memory, alloc); - if (table->table == NULL) - { - bfd_set_error (bfd_error_no_memory); - return FALSE; - } - memset ((void *) table->table, 0, alloc); - table->size = size; - table->entsize = entsize; - table->newfunc = newfunc; - return TRUE; -} - -/* Create a new hash table with the default number of entries. */ - -bfd_boolean -bfd_hash_table_init (struct bfd_hash_table *table, - struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, - struct bfd_hash_table *, - const char *), - unsigned int entsize) -{ - return bfd_hash_table_init_n (table, newfunc, entsize, - bfd_default_hash_table_size); -} - -/* Free a hash table. */ - -void -bfd_hash_table_free (struct bfd_hash_table *table) -{ - objalloc_free (table->memory); - table->memory = NULL; -} - -/* Look up a string in a hash table. */ - -struct bfd_hash_entry * -bfd_hash_lookup (struct bfd_hash_table *table, - const char *string, - bfd_boolean create, - bfd_boolean copy) -{ - const unsigned char *s; - unsigned long hash; - unsigned int c; - struct bfd_hash_entry *hashp; - unsigned int len; - unsigned int index; - - hash = 0; - len = 0; - s = (const unsigned char *) string; - while ((c = *s++) != '\0') - { - hash += c + (c << 17); - hash ^= hash >> 2; - } - len = (s - (const unsigned char *) string) - 1; - hash += len + (len << 17); - hash ^= hash >> 2; - - index = hash % table->size; - for (hashp = table->table[index]; - hashp != NULL; - hashp = hashp->next) - { - if (hashp->hash == hash - && strcmp (hashp->string, string) == 0) - return hashp; - } - - if (! create) - return NULL; - - hashp = (*table->newfunc) (NULL, table, string); - if (hashp == NULL) - return NULL; - if (copy) - { - char *new; - - new = objalloc_alloc ((struct objalloc *) table->memory, len + 1); - if (!new) - { - bfd_set_error (bfd_error_no_memory); - return NULL; - } - memcpy (new, string, len + 1); - string = new; - } - hashp->string = string; - hashp->hash = hash; - hashp->next = table->table[index]; - table->table[index] = hashp; - - return hashp; -} - -/* Replace an entry in a hash table. */ - -void -bfd_hash_replace (struct bfd_hash_table *table, - struct bfd_hash_entry *old, - struct bfd_hash_entry *nw) -{ - unsigned int index; - struct bfd_hash_entry **pph; - - index = old->hash % table->size; - for (pph = &table->table[index]; - (*pph) != NULL; - pph = &(*pph)->next) - { - if (*pph == old) - { - *pph = nw; - return; - } - } - - abort (); -} - -/* Allocate space in a hash table. */ - -void * -bfd_hash_allocate (struct bfd_hash_table *table, - unsigned int size) -{ - void * ret; - - ret = objalloc_alloc ((struct objalloc *) table->memory, size); - if (ret == NULL && size != 0) - bfd_set_error (bfd_error_no_memory); - return ret; -} - -/* Base method for creating a new hash table entry. */ - -struct bfd_hash_entry * -bfd_hash_newfunc (struct bfd_hash_entry *entry, - struct bfd_hash_table *table, - const char *string ATTRIBUTE_UNUSED) -{ - if (entry == NULL) - entry = bfd_hash_allocate (table, sizeof (* entry)); - return entry; -} - -/* Traverse a hash table. */ - -void -bfd_hash_traverse (struct bfd_hash_table *table, - bfd_boolean (*func) (struct bfd_hash_entry *, void *), - void * info) -{ - unsigned int i; - - for (i = 0; i < table->size; i++) - { - struct bfd_hash_entry *p; - - for (p = table->table[i]; p != NULL; p = p->next) - if (! (*func) (p, info)) - return; - } -} - -void -bfd_hash_set_default_size (bfd_size_type hash_size) -{ - /* Extend this prime list if you want more granularity of hash table size. */ - static const bfd_size_type hash_size_primes[] = - { - 251, 509, 1021, 2039, 4051, 8599, 16699, 32749 - }; - size_t index; - - /* Work out best prime number near the hash_size. */ - for (index = 0; index < ARRAY_SIZE (hash_size_primes) - 1; ++index) - if (hash_size <= hash_size_primes[index]) - break; - - bfd_default_hash_table_size = hash_size_primes[index]; -} - -/* A few different object file formats (a.out, COFF, ELF) use a string - table. These functions support adding strings to a string table, - returning the byte offset, and writing out the table. - - Possible improvements: - + look for strings matching trailing substrings of other strings - + better data structures? balanced trees? - + look at reducing memory use elsewhere -- maybe if we didn't have - to construct the entire symbol table at once, we could get by - with smaller amounts of VM? (What effect does that have on the - string table reductions?) */ - -/* An entry in the strtab hash table. */ - -struct strtab_hash_entry -{ - struct bfd_hash_entry root; - /* Index in string table. */ - bfd_size_type index; - /* Next string in strtab. */ - struct strtab_hash_entry *next; -}; - -/* The strtab hash table. */ - -struct bfd_strtab_hash -{ - struct bfd_hash_table table; - /* Size of strtab--also next available index. */ - bfd_size_type size; - /* First string in strtab. */ - struct strtab_hash_entry *first; - /* Last string in strtab. */ - struct strtab_hash_entry *last; - /* Whether to precede strings with a two byte length, as in the - XCOFF .debug section. */ - bfd_boolean xcoff; -}; - -/* Routine to create an entry in a strtab. */ - -static struct bfd_hash_entry * -strtab_hash_newfunc (struct bfd_hash_entry *entry, - struct bfd_hash_table *table, - const char *string) -{ - struct strtab_hash_entry *ret = (struct strtab_hash_entry *) entry; - - /* Allocate the structure if it has not already been allocated by a - subclass. */ - if (ret == NULL) - ret = bfd_hash_allocate (table, sizeof (* ret)); - if (ret == NULL) - return NULL; - - /* Call the allocation method of the superclass. */ - ret = (struct strtab_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->next = NULL; - } - - return (struct bfd_hash_entry *) ret; -} - -/* Look up an entry in an strtab. */ - -#define strtab_hash_lookup(t, string, create, copy) \ - ((struct strtab_hash_entry *) \ - bfd_hash_lookup (&(t)->table, (string), (create), (copy))) - -/* Create a new strtab. */ - -struct bfd_strtab_hash * -_bfd_stringtab_init (void) -{ - struct bfd_strtab_hash *table; - bfd_size_type amt = sizeof (* table); - - table = bfd_malloc (amt); - if (table == NULL) - return NULL; - - if (!bfd_hash_table_init (&table->table, strtab_hash_newfunc, - sizeof (struct strtab_hash_entry))) - { - free (table); - return NULL; - } - - table->size = 0; - table->first = NULL; - table->last = NULL; - table->xcoff = FALSE; - - return table; -} - -/* Create a new strtab in which the strings are output in the format - used in the XCOFF .debug section: a two byte length precedes each - string. */ - -struct bfd_strtab_hash * -_bfd_xcoff_stringtab_init (void) -{ - struct bfd_strtab_hash *ret; - - ret = _bfd_stringtab_init (); - if (ret != NULL) - ret->xcoff = TRUE; - return ret; -} - -/* Free a strtab. */ - -void -_bfd_stringtab_free (struct bfd_strtab_hash *table) -{ - bfd_hash_table_free (&table->table); - free (table); -} - -/* Get the index of a string in a strtab, adding it if it is not - already present. If HASH is FALSE, we don't really use the hash - table, and we don't eliminate duplicate strings. */ - -bfd_size_type -_bfd_stringtab_add (struct bfd_strtab_hash *tab, - const char *str, - bfd_boolean hash, - bfd_boolean copy) -{ - struct strtab_hash_entry *entry; - - if (hash) - { - entry = strtab_hash_lookup (tab, str, TRUE, copy); - if (entry == NULL) - return (bfd_size_type) -1; - } - else - { - entry = bfd_hash_allocate (&tab->table, sizeof (* entry)); - if (entry == NULL) - return (bfd_size_type) -1; - if (! copy) - entry->root.string = str; - else - { - char *n; - - n = bfd_hash_allocate (&tab->table, strlen (str) + 1); - if (n == NULL) - return (bfd_size_type) -1; - entry->root.string = n; - } - entry->index = (bfd_size_type) -1; - entry->next = NULL; - } - - if (entry->index == (bfd_size_type) -1) - { - entry->index = tab->size; - tab->size += strlen (str) + 1; - if (tab->xcoff) - { - entry->index += 2; - tab->size += 2; - } - if (tab->first == NULL) - tab->first = entry; - else - tab->last->next = entry; - tab->last = entry; - } - - return entry->index; -} - -/* Get the number of bytes in a strtab. */ - -bfd_size_type -_bfd_stringtab_size (struct bfd_strtab_hash *tab) -{ - return tab->size; -} - -/* Write out a strtab. ABFD must already be at the right location in - the file. */ - -bfd_boolean -_bfd_stringtab_emit (bfd *abfd, struct bfd_strtab_hash *tab) -{ - bfd_boolean xcoff; - struct strtab_hash_entry *entry; - - xcoff = tab->xcoff; - - for (entry = tab->first; entry != NULL; entry = entry->next) - { - const char *str; - size_t len; - - str = entry->root.string; - len = strlen (str) + 1; - - if (xcoff) - { - bfd_byte buf[2]; - - /* The output length includes the null byte. */ - bfd_put_16 (abfd, (bfd_vma) len, buf); - if (bfd_bwrite ((void *) buf, (bfd_size_type) 2, abfd) != 2) - return FALSE; - } - - if (bfd_bwrite ((void *) str, (bfd_size_type) len, abfd) != len) - return FALSE; - } - - return TRUE; -} |