* elf/dl-lookup.c (dl_new_hash): New functions.

	(_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.

ChangeLog

@@ -1,3 +1,32 @@
+2006-07-10  Ulrich Drepper  <drepper@redhat.com>
+
+	* elf/dl-lookup.c (dl_new_hash): New functions.
+	(_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.
+
 2006-06-27  Ulrich Drepper  <drepper@redhat.com>
 
 	* elf/dl-load.c (open_path): Fix test to determine whether DSO is

Makeconfig

@@ -413,11 +413,20 @@ LDFLAGS.so += $(relro-LDFLAGS)
 LDFLAGS-rtld += $(relro-LDFLAGS)
 endif
 
+ifeq (yes,$(have-hash-style))
+# For the time being we unconditionally use 'both'.  At some time we
+# should declare statically linked code as 'out of luck' and compile
+# with --hash-style=gnu only.
+hashstyle-LDFLAGS = -Wl,--hash-style=both
+LDFLAGS.so += $(hashstyle-LDFLAGS)
+LDFLAGS-rtld += $(hashstyle-LDFLAGS)
+endif
+
 # Command for linking programs with the C library.
 ifndef +link
 +link = $(CC) -nostdlib -nostartfiles -o $@ \
 	      $(sysdep-LDFLAGS) $(config-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
-	      $(combreloc-LDFLAGS) $(relro-LDFLAGS) \
+	      $(combreloc-LDFLAGS) $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \
 	      $(addprefix $(csu-objpfx),$(start-installed-name)) \
 	      $(+preinit) $(+prector) \
 	      $(filter-out $(addprefix $(csu-objpfx),start.o \

NEWS

@@ -1,4 +1,4 @@
-GNU C Library NEWS -- history of user-visible changes.  2006-05-24
+GNU C Library NEWS -- history of user-visible changes.  2006-07-10
 Copyright (C) 1992-2002,2003,2004,2005,2006 Free Software Foundation, Inc.
 See the end for copying conditions.
 
@@ -13,7 +13,7 @@ Version 2.5
 * Allow system admin to configure getaddrinfo with the /etc/gai.conf file.
   Implemented by Ulrich Drepper.
 
-* New Linux interfaces: splice, tee, sync_file_range, vmsplace.
+* New Linux interfaces: splice, tee, sync_file_range, vmsplice.
 
 * New iconv module for MIK.  Contributed by Alexander Shopov.
 
@@ -31,6 +31,8 @@ Version 2.5
 * The interfaces introduced in RFC 3542 have been implemented by
   Ulrich Drepper.
 
+* Support for the new ELF hash table format was added by Ulrich Drepper.
+
 
 Version 2.4
 

config.make.in

@@ -65,6 +65,7 @@ have-libcap = @have_libcap@
 have-cc-with-libunwind = @libc_cv_cc_with_libunwind@
 fno-unit-at-a-time = @fno_unit_at_a_time@
 bind-now = @bindnow@
+have-hash-style = @libc_cv_hashstyle@
 
 static-libgcc = @libc_cv_gcc_static_libgcc@
 

configure

@@ -313,7 +313,7 @@ ac_includes_default="\
 # include <unistd.h>
 #endif"
 
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS with_fp with_cvs enable_check_abi oldest_abi bindnow force_install all_warnings build build_cpu build_vendor build_os host host_cpu host_vendor host_os subdirs add_ons add_on_subdirs base_machine submachine sysnames sysdeps_add_ons INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA LN_S CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC OBJEXT BUILD_CC cross_compiling CPP CXX CXXFLAGS ac_ct_CXX AR OBJDUMP RANLIB ac_ct_RANLIB MIG AS LD PWD_P MAKE MSGFMT MAKEINFO SED AUTOCONF SYSINCLUDES CXX_SYSINCLUDES libc_cv_gcc_static_libgcc BASH libc_cv_have_bash2 KSH libc_cv_have_ksh AWK PERL INSTALL_INFO BISON VERSIONING libc_cv_asm_protected_directive libc_cv_cc_with_libunwind libc_cv_z_nodelete libc_cv_z_nodlopen libc_cv_z_initfirst libc_cv_z_relro libc_cv_Bgroup libc_cv_libgcc_s_suffix libc_cv_as_needed ASFLAGS_config libc_cv_z_combreloc libc_cv_z_execstack libc_cv_fpie fno_unit_at_a_time libc_cv_ssp libc_cv_have_initfini no_whole_archive exceptions LIBGD have_libaudit have_libcap have_selinux EGREP sizeof_long_double libc_cv_gcc_unwind_find_fde uname_sysname uname_release uname_version old_glibc_headers libc_cv_slibdir libc_cv_localedir libc_cv_sysconfdir libc_cv_rootsbindir libc_cv_forced_unwind use_ldconfig ldd_rewrite_script elf xcoff static shared pic_default profile omitfp bounded static_nss nopic_initfini DEFINES mach_interface_list VERSION RELEASE LIBOBJS LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS with_fp with_cvs enable_check_abi oldest_abi bindnow force_install all_warnings build build_cpu build_vendor build_os host host_cpu host_vendor host_os subdirs add_ons add_on_subdirs base_machine submachine sysnames sysdeps_add_ons INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA LN_S CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC OBJEXT BUILD_CC cross_compiling CPP CXX CXXFLAGS ac_ct_CXX AR OBJDUMP RANLIB ac_ct_RANLIB MIG AS LD PWD_P MAKE MSGFMT MAKEINFO SED AUTOCONF SYSINCLUDES CXX_SYSINCLUDES libc_cv_gcc_static_libgcc BASH libc_cv_have_bash2 KSH libc_cv_have_ksh AWK PERL INSTALL_INFO BISON VERSIONING libc_cv_asm_protected_directive libc_cv_cc_with_libunwind libc_cv_z_nodelete libc_cv_z_nodlopen libc_cv_z_initfirst libc_cv_z_relro libc_cv_Bgroup libc_cv_libgcc_s_suffix libc_cv_as_needed ASFLAGS_config libc_cv_z_combreloc libc_cv_z_execstack libc_cv_fpie libc_cv_hashstyle fno_unit_at_a_time libc_cv_ssp libc_cv_have_initfini no_whole_archive exceptions LIBGD have_libaudit have_libcap have_selinux EGREP sizeof_long_double libc_cv_gcc_unwind_find_fde uname_sysname uname_release uname_version old_glibc_headers libc_cv_slibdir libc_cv_localedir libc_cv_sysconfdir libc_cv_rootsbindir libc_cv_forced_unwind use_ldconfig ldd_rewrite_script elf xcoff static shared pic_default profile omitfp bounded static_nss nopic_initfini DEFINES mach_interface_list VERSION RELEASE LIBOBJS LTLIBOBJS'
 ac_subst_files=''
 
 # Initialize some variables set by options.
@@ -5876,6 +5876,33 @@ echo "$as_me:$LINENO: result: $libc_cv_fpie" >&5
 echo "${ECHO_T}$libc_cv_fpie" >&6
 
 
+
+  echo "$as_me:$LINENO: checking for --hash-style option" >&5
+echo $ECHO_N "checking for --hash-style option... $ECHO_C" >&6
+if test "${libc_cv_hashstyle+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+    cat > conftest.c <<EOF
+int _start (void) { return 42; }
+EOF
+  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
+			      -fPIC -shared -o conftest.so conftest.c
+			      -Wl,--hash-style=both -nostdlib 1>&5'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }
+  then
+    libc_cv_hashstyle=yes
+  else
+    libc_cv_hashstyle=no
+  fi
+  rm -f conftest*
+fi
+echo "$as_me:$LINENO: result: $libc_cv_hashstyle" >&5
+echo "${ECHO_T}$libc_cv_hashstyle" >&6
+
 fi
 
 echo "$as_me:$LINENO: checking for -fno-toplevel-reorder" >&5
@@ -8496,6 +8523,7 @@ s,@ASFLAGS_config@,$ASFLAGS_config,;t t
 s,@libc_cv_z_combreloc@,$libc_cv_z_combreloc,;t t
 s,@libc_cv_z_execstack@,$libc_cv_z_execstack,;t t
 s,@libc_cv_fpie@,$libc_cv_fpie,;t t
+s,@libc_cv_hashstyle@,$libc_cv_hashstyle,;t t
 s,@fno_unit_at_a_time@,$fno_unit_at_a_time,;t t
 s,@libc_cv_ssp@,$libc_cv_ssp,;t t
 s,@libc_cv_have_initfini@,$libc_cv_have_initfini,;t t

configure.in

@@ -1589,6 +1589,22 @@ EOF
   rm -f conftest*])
 
   AC_SUBST(libc_cv_fpie)
+
+  AC_CACHE_CHECK(for --hash-style option,
+		 libc_cv_hashstyle, [dnl
+  cat > conftest.c <<EOF
+int _start (void) { return 42; }
+EOF
+  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
+			      -fPIC -shared -o conftest.so conftest.c
+			      -Wl,--hash-style=both -nostdlib 1>&AS_MESSAGE_LOG_FD])
+  then
+    libc_cv_hashstyle=yes
+  else
+    libc_cv_hashstyle=no
+  fi
+  rm -f conftest*])
+  AC_SUBST(libc_cv_hashstyle)
 fi
 
 AC_CACHE_CHECK(for -fno-toplevel-reorder, libc_cv_fno_toplevel_reorder, [dnl

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);
 

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;