* elf/dl-lookup.c (dl_new_hash): New functions.cvs/fedora-glibc-20060710T2206

	(_dl_lookup_symbol_x): Rename hash to old_hash and don't compute
	value here.  Compute new-style hash value.  Pass new hash value
	and reference to variable with the old value to do_lookup_x.
	(_dl_setup_hash): If DT_GNU_HASH is defined, use it and not
	old-style hash table.
	(_dl_debug_bindings): Pass new hash value and reference to variable
	with the old value to do_lookup_x.
	* elf/do-lookup.h (do_lookup_x): Accept additional parameter with
	new-style hash value and change old-style hash value parameter to
	be a reference.  Reoganize functions to determine whether
	new-style hash table is available.  Only fall back on old-style
	table.  If old-style hash value is needed, compute it here.
	* elf/dynamic-link.h (elf_get_dynamic_info): Relocate DT_GNU_HASH
	entry.
	* elf/elf.h: Define SHT_GNU_HASH, DT_GNU_HASH, DT_TLSDEC_PLT,
	DT_TLSDEC_GOT.  Adjust DT_ADDRNUM.
	* include/link.h (struct link_map): Add l_gnu_bitmask_idxbits,
	l_gnu_shift, l_gnu_bitmask, l_gnu_buckets and l_gnu_chain_zero.
	* Makeconfig: If linker supports --hash-style option add it to all
	linker command lines to build DSOs.
	* config.make.in: Define have-hash-style.
	* configure.in: Test whether linker supports --hash-style option.

	* elf/dl-misc.c (_dl_name_match_p): Make MAP parameter const.
	* sysdeps/generic/ldsodefs.h: Adjust prototype.

5 files changed, 208 insertions, 122 deletions

diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 5a7bed1..7cfcc62 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -1,5 +1,5 @@
 /* Look up a symbol in the loaded objects.
-   Copyright (C) 1995-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   Copyright (C) 1995-2005, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -72,6 +72,16 @@ struct sym_val
 #include "do-lookup.h"
 
 
+static uint_fast32_t
+dl_new_hash (const char *s)
+{
+  uint_fast32_t h = 5381;
+  for (unsigned char c = *s; c != '\0'; c = *++s)
+    h = h * 33 + c;
+  return h & 0xffffffff;
+}
+
+
 /* Add extra dependency on MAP to UNDEF_MAP.  */
 static int
 internal_function
@@ -206,7 +216,8 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
 		     const struct r_found_version *version,
 		     int type_class, int flags, struct link_map *skip_map)
 {
-  const unsigned long int hash = _dl_elf_hash (undef_name);
+  const uint_fast32_t new_hash = dl_new_hash (undef_name);
+  unsigned long int old_hash = 0xffffffff;
   struct sym_val current_value = { NULL, NULL };
   struct r_scope_elem **scope = symbol_scope;
 
@@ -229,8 +240,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
   /* Search the relevant loaded objects for a definition.  */
   for (size_t start = i; *scope != NULL; start = 0, ++scope)
     {
-      int res = do_lookup_x (undef_name, hash, *ref, &current_value, *scope,
-			     start, version, flags, skip_map, type_class);
+      int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
+			     &current_value, *scope, start, version, flags,
+			     skip_map, type_class);
       if (res > 0)
 	break;
 
@@ -301,9 +313,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
 	  struct sym_val protected_value = { NULL, NULL };
 
 	  for (scope = symbol_scope; *scope != NULL; i = 0, ++scope)
-	    if (do_lookup_x (undef_name, hash, *ref, &protected_value,
-			     *scope, i, version, flags, skip_map,
-			     ELF_RTYPE_CLASS_PLT) != 0)
+	    if (do_lookup_x (undef_name, new_hash, &old_hash, *ref,
+			     &protected_value, *scope, i, version, flags,
+			     skip_map, ELF_RTYPE_CLASS_PLT) != 0)
 	      break;
 
 	  if (protected_value.s != NULL && protected_value.m != undef_map)
@@ -352,6 +364,31 @@ _dl_setup_hash (struct link_map *map)
   Elf_Symndx *hash;
   Elf_Symndx nchain;
 
+  if (__builtin_expect (map->l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
+  				    + DT_THISPROCNUM + DT_VERSIONTAGNUM
+				    + DT_EXTRANUM + DT_VALNUM] != NULL, 1))
+    {
+      Elf32_Word *hash32
+	= (void *) D_PTR (map, l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
+				      + DT_THISPROCNUM + DT_VERSIONTAGNUM
+				      + DT_EXTRANUM + DT_VALNUM]);
+      map->l_nbuckets = *hash32++;
+      Elf32_Word symbias = *hash32++;
+      Elf32_Word bitmask_nwords = *hash32++;
+      /* Must be a power of two.  */
+      assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0);
+      map->l_gnu_bitmask_idxbits = bitmask_nwords - 1;
+      map->l_gnu_shift = *hash32++;
+
+      map->l_gnu_bitmask = (ElfW(Addr) *) hash32;
+      hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords;
+
+      map->l_gnu_buckets = hash32;
+      hash32 += map->l_nbuckets;
+      map->l_gnu_chain_zero = hash32 - symbias;
+      return;
+    }
+
   if (!map->l_info[DT_HASH])
     return;
   hash = (void *) D_PTR (map, l_info[DT_HASH]);
@@ -399,9 +436,10 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
 	   || GLRO(dl_trace_prelink_map) == GL(dl_ns)[LM_ID_BASE]._ns_loaded)
 	  && undef_map != GL(dl_ns)[LM_ID_BASE]._ns_loaded)
 	{
-	  const unsigned long int hash = _dl_elf_hash (undef_name);
+	  const uint_fast32_t new_hash = dl_new_hash (undef_name);
+	  unsigned long int old_hash = 0xffffffff;
 
-	  do_lookup_x (undef_name, hash, *ref, &val,
+	  do_lookup_x (undef_name, new_hash, &old_hash, *ref, &val,
 		       undef_map->l_local_scope[0], 0, version, 0, NULL,
 		       type_class);
 
diff --git a/elf/dl-misc.c b/elf/dl-misc.c
index 08d6495..6da1e2e 100644
--- a/elf/dl-misc.c
+++ b/elf/dl-misc.c
@@ -1,5 +1,5 @@
 /* Miscellaneous support functions for dynamic linker
-   Copyright (C) 1997-2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1997-2002, 2003, 2004, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -308,7 +308,7 @@ _dl_dprintf (int fd, const char *fmt, ...)
 /* Test whether given NAME matches any of the names of the given object.  */
 int
 internal_function
-_dl_name_match_p (const char *name, struct link_map *map)
+_dl_name_match_p (const char *name, const struct link_map *map)
 {
   if (strcmp (name, map->l_name) == 0)
     return 1;
diff --git a/elf/do-lookup.h b/elf/do-lookup.h
index 7b62b0f..f40ab9d 100644
--- a/elf/do-lookup.h
+++ b/elf/do-lookup.h
@@ -17,32 +17,29 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+
 /* Inner part of the lookup functions.  We return a value > 0 if we
    found the symbol, the value 0 if nothing is found and < 0 if
    something bad happened.  */
 static int
 __attribute_noinline__
-do_lookup_x (const char *undef_name, unsigned long int hash,
-	     const ElfW(Sym) *ref, struct sym_val *result,
-	     struct r_scope_elem *scope, size_t i,
+do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
+	     unsigned long int *old_hash, const ElfW(Sym) *ref,
+	     struct sym_val *result, struct r_scope_elem *scope, size_t i,
 	     const struct r_found_version *const version, int flags,
 	     struct link_map *skip, int type_class)
 {
   struct link_map **list = scope->r_list;
   size_t n = scope->r_nlist;
-  struct link_map *map;
 
   do
     {
-      const ElfW(Sym) *symtab;
-      const char *strtab;
-      const ElfW(Half) *verstab;
+      /* These variables are used in the nested function.  */
       Elf_Symndx symidx;
-      const ElfW(Sym) *sym;
       int num_versions = 0;
       const ElfW(Sym) *versioned_sym = NULL;
 
-      map = list[i]->l_real;
+      const struct link_map *map = list[i]->l_real;
 
       /* Here come the extra test needed for `_dl_lookup_symbol_skip'.  */
       if (map == skip)
@@ -63,109 +60,158 @@ do_lookup_x (const char *undef_name, unsigned long int hash,
 			  map->l_name[0] ? map->l_name : rtld_progname,
 			  map->l_ns);
 
-      symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]);
-      strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
-      verstab = map->l_versyms;
+      /* If the hash table is empty there is nothing to do here.  */
+      if (map->l_nbuckets == 0)
+	continue;
 
-      /* Search the appropriate hash bucket in this object's symbol table
-	 for a definition for the same symbol name.  */
-      for (symidx = map->l_buckets[hash % map->l_nbuckets];
-	   symidx != STN_UNDEF;
-	   symidx = map->l_chain[symidx])
-	{
-	  sym = &symtab[symidx];
-
-	  assert (ELF_RTYPE_CLASS_PLT == 1);
-	  if ((sym->st_value == 0 /* No value.  */
-#ifdef USE_TLS
-	       && ELFW(ST_TYPE) (sym->st_info) != STT_TLS
-#endif
-	       )
-	      || (type_class & (sym->st_shndx == SHN_UNDEF)))
-	    continue;
-
-	  if (ELFW(ST_TYPE) (sym->st_info) > STT_FUNC
-#ifdef USE_TLS
-	      && ELFW(ST_TYPE) (sym->st_info) != STT_TLS
-#endif
-	      )
-	    /* Ignore all but STT_NOTYPE, STT_OBJECT and STT_FUNC
-	       entries (and STT_TLS if TLS is supported) since these
-	       are no code/data definitions.  */
-	    continue;
-
-	  if (sym != ref && strcmp (strtab + sym->st_name, undef_name))
-	    /* Not the symbol we are looking for.  */
-	    continue;
-
-	  if (version != NULL)
-	    {
-	      if (__builtin_expect (verstab == NULL, 0))
-		{
-		  /* We need a versioned symbol but haven't found any.  If
-		     this is the object which is referenced in the verneed
-		     entry it is a bug in the library since a symbol must
-		     not simply disappear.
-
-		     It would also be a bug in the object since it means that
-		     the list of required versions is incomplete and so the
-		     tests in dl-version.c haven't found a problem.*/
-		  assert (version->filename == NULL
-			  || ! _dl_name_match_p (version->filename, map));
-
-		  /* Otherwise we accept the symbol.  */
-		}
-	      else
-		{
-		  /* We can match the version information or use the
-		     default one if it is not hidden.  */
-		  ElfW(Half) ndx = verstab[symidx] & 0x7fff;
-		  if ((map->l_versions[ndx].hash != version->hash
-		       || strcmp (map->l_versions[ndx].name, version->name))
-		      && (version->hidden || map->l_versions[ndx].hash
-			  || (verstab[symidx] & 0x8000)))
-		    /* It's not the version we want.  */
-		    continue;
-		}
-	    }
-	  else
-	    {
-	      /* No specific version is selected.  There are two ways we
-		 can got here:
+      /* The tables for this map.  */
+      const ElfW(Sym) *symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]);
+      const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
+
+
+      /* Nested routine to check whether the symbol matches.  */
+      const ElfW(Sym) *
+      __attribute_noinline__
+      check_match (const ElfW(Sym) *sym)
+      {
+	assert (ELF_RTYPE_CLASS_PLT == 1);
+	if (__builtin_expect ((sym->st_value == 0 /* No value.  */
+			       && ELFW(ST_TYPE) (sym->st_info) != STT_TLS)
+			      || (type_class & (sym->st_shndx == SHN_UNDEF)),
+			      0))
+	  return NULL;
+
+	if (__builtin_expect (ELFW(ST_TYPE) (sym->st_info) > STT_FUNC
+			      && ELFW(ST_TYPE) (sym->st_info) != STT_TLS, 0))
+	  /* Ignore all but STT_NOTYPE, STT_OBJECT and STT_FUNC
+	     entries (and STT_TLS if TLS is supported) since these
+	     are no code/data definitions.  */
+	  return NULL;
+
+	if (sym != ref && strcmp (strtab + sym->st_name, undef_name))
+	  /* Not the symbol we are looking for.  */
+	  return NULL;
+
+	const ElfW(Half) *verstab = map->l_versyms;
+	if (version != NULL)
+	  {
+	    if (__builtin_expect (verstab == NULL, 0))
+	      {
+		/* We need a versioned symbol but haven't found any.  If
+		   this is the object which is referenced in the verneed
+		   entry it is a bug in the library since a symbol must
+		   not simply disappear.
+
+		   It would also be a bug in the object since it means that
+		   the list of required versions is incomplete and so the
+		   tests in dl-version.c haven't found a problem.*/
+		assert (version->filename == NULL
+			|| ! _dl_name_match_p (version->filename, map));
 
-		 - a binary which does not include versioning information
-		   is loaded
+		/* Otherwise we accept the symbol.  */
+	      }
+	    else
+	      {
+		/* We can match the version information or use the
+		   default one if it is not hidden.  */
+		ElfW(Half) ndx = verstab[symidx] & 0x7fff;
+		if ((map->l_versions[ndx].hash != version->hash
+		     || strcmp (map->l_versions[ndx].name, version->name))
+		    && (version->hidden || map->l_versions[ndx].hash
+			|| (verstab[symidx] & 0x8000)))
+		  /* It's not the version we want.  */
+		  return NULL;
+	      }
+	  }
+	else
+	  {
+	    /* No specific version is selected.  There are two ways we
+	       can got here:
 
-		 - dlsym() instead of dlvsym() is used to get a symbol which
-		   might exist in more than one form
+	       - a binary which does not include versioning information
+	       is loaded
 
-		 If the library does not provide symbol version
-		 information there is no problem at at: we simply use the
-		 symbol if it is defined.
+	       - dlsym() instead of dlvsym() is used to get a symbol which
+	       might exist in more than one form
 
-		 These two lookups need to be handled differently if the
-		 library defines versions.  In the case of the old
-		 unversioned application the oldest (default) version
-		 should be used.  In case of a dlsym() call the latest and
-		 public interface should be returned.  */
-	      if (verstab != NULL)
+	       If the library does not provide symbol version information
+	       there is no problem at at: we simply use the symbol if it
+	       is defined.
+
+	       These two lookups need to be handled differently if the
+	       library defines versions.  In the case of the old
+	       unversioned application the oldest (default) version
+	       should be used.  In case of a dlsym() call the latest and
+	       public interface should be returned.  */
+	    if (verstab != NULL)
+	      {
+		if ((verstab[symidx] & 0x7fff)
+		    >= ((flags & DL_LOOKUP_RETURN_NEWEST) ? 2 : 3))
+		  {
+		    /* Don't accept hidden symbols.  */
+		    if ((verstab[symidx] & 0x8000) == 0
+			&& num_versions++ == 0)
+		      /* No version so far.  */
+		      versioned_sym = sym;
+
+		    return NULL;
+		  }
+	      }
+	  }
+
+	/* There cannot be another entry for this symbol so stop here.  */
+	return sym;
+      }
+
+      const ElfW(Sym) *sym;
+      const ElfW(Addr) *bitmask = map->l_gnu_bitmask;
+      if (__builtin_expect (bitmask != NULL, 1))
+	{
+	  ElfW(Addr) bitmask_word
+	    = bitmask[(new_hash / __ELF_NATIVE_CLASS)
+		      & map->l_gnu_bitmask_idxbits];
+
+	  unsigned int hashbit1 = new_hash & (__ELF_NATIVE_CLASS - 1);
+	  unsigned int hashbit2 = ((new_hash >> map->l_gnu_shift)
+				   & (__ELF_NATIVE_CLASS - 1));
+
+	  if (__builtin_expect ((bitmask_word >> hashbit1)
+				& (bitmask_word >> hashbit2) & 1, 0))
+	    {
+	      Elf32_Word bucket = map->l_gnu_buckets[new_hash
+						     % map->l_nbuckets];
+	      if (bucket != 0)
 		{
-		  if ((verstab[symidx] & 0x7fff)
-		      >= ((flags & DL_LOOKUP_RETURN_NEWEST) ? 2 : 3))
-		    {
-		      /* Don't accept hidden symbols.  */
-		      if ((verstab[symidx] & 0x8000) == 0
-			  && num_versions++ == 0)
-			/* No version so far.  */
-			versioned_sym = sym;
+		  const Elf32_Word *hasharr = &map->l_gnu_chain_zero[bucket];
 
-		      continue;
-		    }
+		  do
+		    if ((*hasharr & ~1u) == (new_hash & ~1u))
+		      {
+			symidx = hasharr - map->l_gnu_chain_zero;
+			sym = check_match (&symtab[symidx]);
+			if (sym != NULL)
+			  goto found_it;
+		      }
+		  while ((*hasharr++ & 1u) == 0);
 		}
 	    }
+	}
+      else
+	{
+	  if (*old_hash == 0xffffffff)
+	    *old_hash = _dl_elf_hash (undef_name);
 
-	  /* There cannot be another entry for this symbol so stop here.  */
-	  goto found_it;
+	  /* Use the old SysV-style hash table.  Search the appropriate
+	     hash bucket in this object's symbol table for a definition
+	     for the same symbol name.  */
+	  for (symidx = map->l_buckets[*old_hash % map->l_nbuckets];
+	       symidx != STN_UNDEF;
+	       symidx = map->l_chain[symidx])
+	    {
+	      sym = check_match (&symtab[symidx]);
+	      if (sym != NULL)
+		goto found_it;
+	    }
 	}
 
       /* If we have seen exactly one versioned symbol while we are
@@ -186,7 +232,7 @@ do_lookup_x (const char *undef_name, unsigned long int hash,
 		  if (! result->s)
 		    {
 		      result->s = sym;
-		      result->m = map;
+		      result->m = (struct link_map *) map;
 		    }
 		  break;
 		}
@@ -194,7 +240,7 @@ do_lookup_x (const char *undef_name, unsigned long int hash,
 	    case STB_GLOBAL:
 	      /* Global definition.  Just what we need.  */
 	      result->s = sym;
-	      result->m = map;
+	      result->m = (struct link_map *) map;
 	      return 1;
 	    default:
 	      /* Local symbols are ignored.  */
@@ -213,7 +259,3 @@ do_lookup_x (const char *undef_name, unsigned long int hash,
   /* We have not found anything until now.  */
   return 0;
 }
-
-#undef FCT
-#undef ARG
-#undef VERSIONED
diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index cf0d223..7eb9a36 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -1,5 +1,5 @@
 /* Inline functions for dynamic linking.
-   Copyright (C) 1995-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   Copyright (C) 1995-2005, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -143,6 +143,8 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
 # endif
       ADJUST_DYN_INFO (DT_JMPREL);
       ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
+      ADJUST_DYN_INFO (DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM
+		       + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM);
 # undef ADJUST_DYN_INFO
       assert (cnt <= DL_RO_DYN_TEMP_CNT);
     }
diff --git a/elf/elf.h b/elf/elf.h
index 344f252..dae3597 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -329,7 +329,8 @@ typedef struct
 #define SHT_GROUP	  17		/* Section group */
 #define SHT_SYMTAB_SHNDX  18		/* Extended section indeces */
 #define	SHT_NUM		  19		/* Number of defined types.  */
-#define SHT_LOOS	  0x60000000	/* Start OS-specific */
+#define SHT_LOOS	  0x60000000	/* Start OS-specific.  */
+#define SHT_GNU_HASH	  0x6ffffff6	/* GNU-style hash table.  */
 #define SHT_GNU_LIBLIST	  0x6ffffff7	/* Prelink library list */
 #define SHT_CHECKSUM	  0x6ffffff8	/* Checksum for DSO content.  */
 #define SHT_LOSUNW	  0x6ffffffa	/* Sun-specific low bound.  */
@@ -699,6 +700,9 @@ typedef struct
    If any adjustment is made to the ELF object after it has been
    built these entries will need to be adjusted.  */
 #define DT_ADDRRNGLO	0x6ffffe00
+#define DT_GNU_HASH	0x6ffffef5	/* GNU-style hash table.  */
+#define DT_TLSDESC_PLT	0x6ffffef6
+#define DT_TLSDESC_GOT	0x6ffffef7
 #define DT_GNU_CONFLICT	0x6ffffef8	/* Start of conflict section */
 #define DT_GNU_LIBLIST	0x6ffffef9	/* Library list */
 #define DT_CONFIG	0x6ffffefa	/* Configuration information.  */
@@ -709,7 +713,7 @@ typedef struct
 #define DT_SYMINFO	0x6ffffeff	/* Syminfo table.  */
 #define DT_ADDRRNGHI	0x6ffffeff
 #define DT_ADDRTAGIDX(tag)	(DT_ADDRRNGHI - (tag))	/* Reverse order! */
-#define DT_ADDRNUM 10
+#define DT_ADDRNUM 11
 
 /* The versioning entry types.  The next are defined as part of the
    GNU extension.  */