[PATCH] __attribute__((visibility(...))) for ld.so
Jakub Jelinek
jakub@redhat.com
Thu Feb 28 11:33:00 GMT 2002
Hi!
This patch makes ld.so on ia32 smaller by another 1KB and on ia64 by 1.5KB
by killing some unnecessary memory dereferences.
Bootstrapped on i386/i686/ia64/alpha/alphaev6.
2002-02-28 Jakub Jelinek <jakub@redhat.com>
* elf/rtld.c (_rtld_global): Remove .protected.
(_rtld_local): Strong alias to _rtld_global.
* elf/Makefile (CFLAGS-.os): Add -D_RTLD_LOCAL if compiling rtld
only .os object.
* sysdeps/generic/ldsodefs.h (GL): If SHARED and _RTLD_LOCAL, use
_rtld_local instead of _rtld_global.
(_rtld_local): Add hidden extern, possibly in .sdata section.
--- libc/elf/rtld.c.jj Thu Feb 28 12:31:20 2002
+++ libc/elf/rtld.c Thu Feb 28 16:18:08 2002
@@ -91,11 +91,7 @@ struct rtld_global _rtld_global =
._dl_hwcap_mask = HWCAP_IMPORTANT,
._dl_load_lock = _LIBC_LOCK_RECURSIVE_INITIALIZER
};
-/* There must only be the definition in ld.so itself. */
-#ifdef HAVE_PROTECTED
-asm (".protected _rtld_global");
-#endif
-
+strong_alias (_rtld_global, _rtld_local);
static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
ElfW(Addr) *user_entry);
--- libc/elf/Makefile.jj Mon Feb 18 23:39:22 2002
+++ libc/elf/Makefile Thu Feb 28 16:02:19 2002
@@ -250,6 +250,8 @@ CFLAGS-ldconfig.c = $(SYSCONF-FLAGS) -D'
CFLAGS-dl-cache.c = $(SYSCONF-FLAGS)
CFLAGS-cache.c = $(SYSCONF-FLAGS)
+CFLAGS-.os += $(if $(filter $(@F),$(patsubst %,%.os,$(all-rtld-routines))),-D_RTLD_LOCAL)
+
test-modules = $(addprefix $(objpfx),$(addsuffix .so,$(strip $(modules-names))))
generated += $(addsuffix .so,$(strip $(modules-names)))
--- libc/sysdeps/alpha/dl-machine.h.jj Thu Feb 28 12:33:15 2002
+++ libc/sysdeps/alpha/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -328,7 +328,7 @@ $fixup_stack_ret: \n\
" RTLD_START_SPECIAL_INIT " \n\
/* Call _dl_init(_dl_loaded, argc, argv, envp) to run \n\
initializers. */ \n\
- ldq $16, _rtld_global \n\
+ ldq $16, _rtld_local \n\
ldq $17, 0($sp) \n\
lda $18, 8($sp) \n\
s8addq $17, 8, $19 \n\
--- libc/sysdeps/arm/dl-machine.h.jj Mon Feb 4 17:34:53 2002
+++ libc/sysdeps/arm/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -324,7 +324,7 @@ _dl_start_user:
.L_STACK_END:
.word __libc_stack_end(GOT)
.L_LOADED:
- .word _rtld_global(GOT)
+ .word _rtld_local(GOT)
.previous\n\
");
--- libc/sysdeps/generic/ldsodefs.h.jj Thu Feb 28 12:33:16 2002
+++ libc/sysdeps/generic/ldsodefs.h Thu Feb 28 16:08:44 2002
@@ -199,7 +199,11 @@ typedef void (*receiver_fct) (int, const
# define GL(name) _##name
#else
# define EXTERN
-# define GL(name) _rtld_global._##name
+# ifdef _RTLD_LOCAL
+# define GL(name) _rtld_local._##name
+# else
+# define GL(name) _rtld_global._##name
+# endif
struct rtld_global
{
#endif
@@ -371,6 +375,19 @@ struct rtld_global
#ifdef SHARED
};
extern struct rtld_global _rtld_global;
+# ifdef _RTLD_LOCAL
+# ifdef HAVE_VISIBILITY_ATTRIBUTE
+# ifdef HAVE_SDATA_SECTION
+# define __rtld_local_attribute__ \
+ __attribute__ ((visibility ("hidden"), section (".sdata")))
+# else
+# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
+# endif
+# else
+# define __rtld_local_attribute__
+# endif
+extern struct rtld_global _rtld_local __rtld_local_attribute__;
+# endif
#endif
#undef EXTERN
--- libc/sysdeps/hppa/dl-machine.h.jj Mon Feb 4 17:35:18 2002
+++ libc/sysdeps/hppa/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -362,8 +362,8 @@ asm ( \
" stw %r24,-44(%sp)\n" \
\
".Lnofix:\n" \
-" addil LT'_rtld_global,%r19\n" \
-" ldw RT'_rtld_global(%r1),%r26\n" \
+" addil LT'_rtld_local,%r19\n" \
+" ldw RT'_rtld_local(%r1),%r26\n" \
" bl set_dp, %r2\n" \
" ldw 0(%r26),%r26\n" \
\
--- libc/sysdeps/cris/dl-machine.h.jj Mon Feb 4 17:34:53 2002
+++ libc/sysdeps/cris/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -212,7 +212,7 @@ _dl_start_user:
move.d $sp,$r12
addq 4,$r12
; main_map: at _dl_loaded.
- move.d [$r0+_rtld_global:GOT16],$r9
+ move.d [$r0+_rtld_local:GOT16],$r9
move.d [$r9],$r10
move.d _dl_init_internal:PLTG,$r9
add.d $r0,$r9
--- libc/sysdeps/i386/dl-machine.h.jj Mon Feb 18 23:39:52 2002
+++ libc/sysdeps/i386/dl-machine.h Thu Feb 28 17:33:58 2002
@@ -239,11 +239,10 @@ _dl_start_user:\n\
" RTLD_START_SPECIAL_INIT "\n\
# Load the parameters again.\n\
# (eax, edx, ecx, *--esp) = (_dl_loaded, argc, argv, envp)\n\
- movl _rtld_global@GOT(%ebx), %esi\n\
- leal 8(%esp,%edx,4), %eax\n\
+ movl _rtld_local@GOTOFF(%ebx), %eax\n\
+ leal 8(%esp,%edx,4), %esi\n\
leal 4(%esp), %ecx\n\
- pushl %eax\n\
- movl (%esi), %eax\n\
+ pushl %esi\n\
# Call the function to run the initializers.\n\
call _dl_init_internal@PLT\n\
# Pass our finalizer function to the user in %edx, as per ELF ABI.\n\
--- libc/sysdeps/ia64/dl-machine.h.jj Mon Feb 4 17:35:18 2002
+++ libc/sysdeps/ia64/dl-machine.h Thu Feb 28 17:15:46 2002
@@ -381,7 +381,7 @@ elf_machine_runtime_setup (struct link_m
" { .mmi\n" \
" mov out3 = r11\n" \
" sub r17 = r17, r3 /* Substract _dl_skip_args. */\n" \
-" addl out0 = @ltoff(_rtld_global), gp\n" \
+" addl out0 = @gprel(_rtld_local), gp\n" \
" }\n" \
"1: /* Copy env. */\n" \
" { .mfi\n" \
@@ -396,11 +396,9 @@ elf_machine_runtime_setup (struct link_m
" }\n" \
" { .mmb\n" \
" st8 [r10] = out1 /* Record the new argc. */\n" \
-" ld8 out0 = [out0]\n" \
-" ;;\n" \
+" ld8 out0 = [out0] /* get the linkmap */\n" \
" }\n" \
" { .mmb\n" \
-" ld8 out0 = [out0] /* get the linkmap */\n" \
" st8 [r2] = r17 /* Load the new _dl_argv. */\n" \
" br.call.sptk.many b0 = _dl_init_internal#\n" \
" ;;\n" \
--- libc/sysdeps/m68k/dl-machine.h.jj Mon Feb 4 17:35:19 2002
+++ libc/sysdeps/m68k/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -176,7 +176,7 @@ _dl_start_user:\n\
pea 8(%sp, %d1*4)\n\
pea 8(%sp)\n\
move.l %d1, -(%sp)\n\
- move.l ([_rtld_global@GOT.w, %a5]), -(%sp)\n\
+ move.l ([_rtld_local@GOT.w, %a5]), -(%sp)\n\
jbsr _dl_init_internal@PLTPC\n\
addq.l #8, %sp\n\
addq.l #8, %sp\n\
--- libc/sysdeps/mips/mips64/dl-machine.h.jj Mon Feb 4 17:35:19 2002
+++ libc/sysdeps/mips/mips64/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -480,7 +480,7 @@ _dl_start_user:\n\
# Save back the modified argument count.\n\
sd $4, 0($29)\n\
1: # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
- ld $4, _rtld_global\n\
+ ld $4, _rtld_local\n\
ld $5, 0($29)\n\
dla $6, 4($29)\n\
dla $7, 8($29)\n\
@@ -492,7 +492,7 @@ _dl_start_user:\n\
dla $31, _dl_fini\n\
# Jump to the user entry point.\n\
1: # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
- lw $4, _rtld_global\n\
+ lw $4, _rtld_local\n\
lw $5, 0($29)\n\
la $6, 4($29)\n\
la $7, 8($29)\n\
--- libc/sysdeps/mips/dl-machine.h.jj Sat Feb 9 00:32:19 2002
+++ libc/sysdeps/mips/dl-machine.h Thu Feb 28 16:48:57 2002
@@ -441,7 +441,7 @@ _dl_start_user:\n\
# Save back the modified argument count.\n\
sw $4, 0($29)\n\
1: # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
- lw $4, _rtld_global\n\
+ lw $4, _rtld_local\n\
lw $5, 0($29)\n\
la $6, 4($29)\n\
sll $7, $5, 2\n\
--- libc/sysdeps/sparc/sparc32/dl-machine.h.jj Mon Feb 4 17:35:19 2002
+++ libc/sysdeps/sparc/sparc32/dl-machine.h Thu Feb 28 16:48:58 2002
@@ -312,9 +312,9 @@ _dl_start_user:
bne 23b
add %i1, 8, %i1
/* %o0 = _dl_loaded, %o1 = argc, %o2 = argv, %o3 = envp. */
-3: sethi %hi(_rtld_global), %o0
+3: sethi %hi(_rtld_local), %o0
add %sp, 23*4, %o2
- orcc %o0, %lo(_rtld_global), %o0
+ orcc %o0, %lo(_rtld_local), %o0
sll %i5, 2, %o3
ld [%l7+%o0], %o0
add %o3, 4, %o3
--- libc/sysdeps/sparc/sparc64/dl-machine.h.jj Mon Feb 4 17:35:20 2002
+++ libc/sysdeps/sparc/sparc64/dl-machine.h Thu Feb 28 16:48:58 2002
@@ -745,9 +745,9 @@ elf_machine_runtime_setup (struct link_m
" add %i1, 16, %i1\n" \
" stx %l5, [%l4]\n" \
" /* %o0 = _dl_loaded, %o1 = argc, %o2 = argv, %o3 = envp. */\n" \
-"2: sethi %hi(_rtld_global), %o0\n" \
+"2: sethi %hi(_rtld_local), %o0\n" \
" add %sp, " __S(STACK_BIAS) " + 23*8, %o2\n" \
-" orcc %o0, %lo(_rtld_global), %o0\n" \
+" orcc %o0, %lo(_rtld_local), %o0\n" \
" sllx %i5, 3, %o3\n" \
" ldx [%l7 + %o0], %o0\n" \
" add %o3, 8, %o3\n" \
--- libc/sysdeps/sh/dl-machine.h.jj Mon Feb 4 17:35:19 2002
+++ libc/sysdeps/sh/dl-machine.h Thu Feb 28 16:48:58 2002
@@ -388,7 +388,7 @@ _dl_start_user:\n\
.L_dl_init:\n\
.long _dl_init_internal@PLT\n\
.L_dl_loaded:\n\
- .long _rtld_global@GOT\n\
+ .long _rtld_local@GOT\n\
.L_dl_starting_up:\n\
.long _dl_starting_up@GOT\n\
.L_dl_fini:\n\
--- libc/sysdeps/s390/s390-32/dl-machine.h.jj Mon Feb 4 17:35:19 2002
+++ libc/sysdeps/s390/s390-32/dl-machine.h Thu Feb 28 16:48:58 2002
@@ -287,7 +287,7 @@ _dl_start_user:\n\
# Call the function to run the initializers.\n\
# Load the parameters:\n\
# (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
- l %r2,_rtld_global@GOT(%r12)\n\
+ l %r2,_rtld_local@GOT(%r12)\n\
l %r2,0(%r2)\n\
l %r3,96(%r15)\n\
la %r4,100(%r15)\n\
--- libc/sysdeps/s390/s390-64/dl-machine.h.jj Mon Feb 4 17:35:19 2002
+++ libc/sysdeps/s390/s390-64/dl-machine.h Thu Feb 28 16:48:58 2002
@@ -262,7 +262,7 @@ _dl_start_user:\n\
# Call the function to run the initializers.\n\
# Load the parameters:\n\
# (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
- lghi %r2,_rtld_global@GOT
+ lghi %r2,_rtld_local@GOT
lg %r2,0(%r2,%r12)\n\
lg %r2,0(%r2)\n\
lg %r3,160(%r15)\n\
--- libc/sysdeps/x86_64/dl-machine.h.jj Mon Feb 4 17:35:21 2002
+++ libc/sysdeps/x86_64/dl-machine.h Thu Feb 28 16:48:58 2002
@@ -250,7 +250,7 @@ _dl_start_user:\n\
# argc -> rsi\n\
movq %rdx, %rsi\n\
# _dl_loaded -> rdi\n\
- movq _rtld_global@GOTPCREL(%rip), %rdi\n\
+ movq _rtld_local@GOTPCREL(%rip), %rdi\n\
movq (%rdi), %rdi\n\
# env -> rcx\n\
leaq 16(%rsp,%rdx,8), %rcx\n\
--- libc/configure.in.jj Thu Feb 28 12:31:19 2002
+++ libc/configure.in Thu Feb 28 13:23:13 2002
@@ -1001,6 +1001,44 @@ EOF
AC_SUBST(libc_cv_asm_protected_directive)
AC_DEFINE(HAVE_PROTECTED)
+ if test $libc_cv_asm_protected_directive = yes; then
+ AC_CACHE_CHECK(whether __attribute__((visibility())) is supported,
+ libc_cv_visibility_attribute,
+ [cat > conftest.c <<EOF
+ int foo __attribute__ ((visibility ("hidden"))) = 1;
+ int bar __attribute__ ((visibility ("protected"))) = 1;
+EOF
+ libc_cv_visibility_attribute=no
+ if ${CC-cc} -Werror -S conftest.c -o conftest.s >/dev/null 2>&1; then
+ if grep '\.hidden.*foo' conftest.s >/dev/null; then
+ if grep '\.protected.*bar' conftest.s >/dev/null; then
+ libc_cv_visibility_attribute=yes
+ fi
+ fi
+ fi
+ rm -f conftest.[cs]
+ ])
+ if test $libc_cv_visibility_attribute = yes; then
+ AC_DEFINE(HAVE_VISIBILITY_ATTRIBUTE)
+ fi
+ fi
+
+ if test $libc_cv_visibility_attribute = yes -a $gnu_ld = yes; then
+ AC_CACHE_CHECK(whether to put _rtld_local into .sdata section,
+ libc_cv_have_sdata_section,
+ [echo "int i;" > conftest.c
+ libc_cv_have_sdata_section=no
+ if ${CC-cc} -shared -Wl,--verbose conftest.c -o conftest.so 2>&1 \
+ | grep '\.sdata' >/dev/null; then
+ libc_cv_have_sdata_section=yes
+ fi
+ rm -f conftest.c conftest.so
+ ])
+ if test $libc_cv_have_sdata_section = yes; then
+ AC_DEFINE(HAVE_SDATA_SECTION)
+ fi
+ fi
+
AC_CACHE_CHECK(for -z nodelete option,
libc_cv_z_nodelete, [dnl
cat > conftest.c <<EOF
--- libc/configure.jj Thu Feb 28 12:36:21 2002
+++ libc/configure Thu Feb 28 13:23:28 2002
@@ -2806,6 +2806,62 @@ echo "$ac_t""$libc_cv_asm_protected_dire
EOF
+ if test $libc_cv_asm_protected_directive = yes; then
+ echo $ac_n "checking whether __attribute__((visibility())) is supported""... $ac_c" 1>&6
+echo "configure:2812: checking whether __attribute__((visibility())) is supported" >&5
+if eval "test \"`echo '$''{'libc_cv_visibility_attribute'+set}'`\" = set"; then
+ echo $ac_n "(cached) $ac_c" 1>&6
+else
+ cat > conftest.c <<EOF
+ int foo __attribute__ ((visibility ("hidden"))) = 1;
+ int bar __attribute__ ((visibility ("protected"))) = 1;
+EOF
+ libc_cv_visibility_attribute=no
+ if ${CC-cc} -Werror -S conftest.c -o conftest.s >/dev/null 2>&1; then
+ if grep '\.hidden.*foo' conftest.s >/dev/null; then
+ if grep '\.protected.*bar' conftest.s >/dev/null; then
+ libc_cv_visibility_attribute=yes
+ fi
+ fi
+ fi
+ rm -f conftest.cs
+
+fi
+
+echo "$ac_t""$libc_cv_visibility_attribute" 1>&6
+ if test $libc_cv_visibility_attribute = yes; then
+ cat >> confdefs.h <<\EOF
+#define HAVE_VISIBILITY_ATTRIBUTE 1
+EOF
+
+ fi
+ fi
+
+ if test $libc_cv_visibility_attribute = yes -a $gnu_ld = yes; then
+ echo $ac_n "checking whether to put _rtld_local into .sdata section""... $ac_c" 1>&6
+echo "configure:2842: checking whether to put _rtld_local into .sdata section" >&5
+if eval "test \"`echo '$''{'libc_cv_have_sdata_section'+set}'`\" = set"; then
+ echo $ac_n "(cached) $ac_c" 1>&6
+else
+ echo "int i;" > conftest.c
+ libc_cv_have_sdata_section=no
+ if ${CC-cc} -shared -Wl,--verbose conftest.c -o conftest.so 2>&1 \
+ | grep '\.sdata' >/dev/null; then
+ libc_cv_have_sdata_section=yes
+ fi
+ rm -f conftest.c conftest.so
+
+fi
+
+echo "$ac_t""$libc_cv_have_sdata_section" 1>&6
+ if test $libc_cv_have_sdata_section = yes; then
+ cat >> confdefs.h <<\EOF
+#define HAVE_SDATA_SECTION 1
+EOF
+
+ fi
+ fi
+
echo $ac_n "checking for -z nodelete option""... $ac_c" 1>&6
echo "configure:2811: checking for -z nodelete option" >&5
if eval "test \"`echo '$''{'libc_cv_z_nodelete'+set}'`\" = set"; then
--- libc/config.h.in.jj Mon Feb 18 23:39:07 2002
+++ libc/config.h.in Thu Feb 28 13:21:39 2002
@@ -102,6 +102,12 @@
/* Define if the assembler supported .protected. */
#undef HAVE_PROTECTED
+/* Define if the compiler supports __attribute__ ((visibility (...))). */
+#undef HAVE_VISIBILITY_ATTRIBUTE
+
+/* Define if _rtld_local structure should be forced into .sdata section. */
+#undef HAVE_SDATA_SECTION
+
/* Define if binutils support TLS handling. */
#undef HAVE_TLS_SUPPORT
Jakub
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