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Don't use hidden visibility in libc.a with PIE on i386

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On i386, when multi-arch is enabled, all external functions must be
called via PIC PLT in PIE, which requires setting up EBX register,
since they may be IFUNC functions.

	* config.h.in (NO_HIDDEN_EXTERN_FUNC_IN_PIE): New.
	* include/libc-symbols.h (__hidden_proto_hiddenattr): Add check
	for PIC and NO_HIDDEN_EXTERN_FUNC_IN_PIE.
	* sysdeps/i386/configure.ac (NO_HIDDEN_EXTERN_FUNC_IN_PIE): New
	AC_DEFINE if multi-arch is enabled.
	* sysdeps/i386/configure: Regenerated.
This commit is contained in:
H.J. Lu 2017-10-04 17:18:23 -07:00
parent a67029ff12
commit ee417882e0
5 changed files with 26 additions and 1 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2017-10-04 H.J. Lu <hongjiu.lu@intel.com>
* config.h.in (NO_HIDDEN_EXTERN_FUNC_IN_PIE): New.
* include/libc-symbols.h (__hidden_proto_hiddenattr): Add check
for PIC and NO_HIDDEN_EXTERN_FUNC_IN_PIE.
* sysdeps/i386/configure.ac (NO_HIDDEN_EXTERN_FUNC_IN_PIE): New
AC_DEFINE if multi-arch is enabled.
* sysdeps/i386/configure: Regenerated.
2017-10-04 H.J. Lu <hongjiu.lu@intel.com>
* Makeconfig (+link-static-before-libc): Use

4
config.h.in
View File

@ -85,6 +85,10 @@
and does not need relocations. */
#undef PI_STATIC_AND_HIDDEN
/* Define this to disable the 'hidden_proto' et al macros in
include/libc-symbols.h that avoid PLT slots in PIE. */
#undef NO_HIDDEN_EXTERN_FUNC_IN_PIE
/* Define this to disable the 'hidden_proto' et al macros in
include/libc-symbols.h that avoid PLT slots in the shared objects. */
#undef NO_HIDDEN

1
include/libc-symbols.h
View File

@ -507,6 +507,7 @@ for linking")
#else
# ifndef __ASSEMBLER__
# if !defined SHARED && IS_IN (libc) && !defined LIBC_NONSHARED \
&& (!defined PIC || !defined NO_HIDDEN_EXTERN_FUNC_IN_PIE) \
&& !defined NO_HIDDEN
# define __hidden_proto_hiddenattr(attrs...) \
__attribute__ ((visibility ("hidden"), ##attrs))

7
sysdeps/i386/configure vendored
View File

@ -26,7 +26,7 @@ libc_compiler_builtin_inlined=no
cat > conftest.c <<EOF
int _start (void) { int a, b, c; __sync_val_compare_and_swap (&a, b, c); return 0; }
EOF
if ! { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
if ! { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
-O0 -nostdlib -nostartfiles
-S conftest.c -o - | fgrep "__sync_val_compare_and_swap"
1>&5'
@ -79,3 +79,8 @@ fi
$as_echo "#define PI_STATIC_AND_HIDDEN 1" >>confdefs.h
if test x"$multi_arch" != xno; then
$as_echo "#define NO_HIDDEN_EXTERN_FUNC_IN_PIE 1" >>confdefs.h
fi

6
sysdeps/i386/configure.ac
View File

@ -48,3 +48,9 @@ fi
dnl It is always possible to access static and hidden symbols in an
dnl position independent way.
AC_DEFINE(PI_STATIC_AND_HIDDEN)
dnl When multi-arch is enabled, all external functions must be called
dnl via PIC PLT in PIE, which requires setting up EBX register.
if test x"$multi_arch" != xno; then
AC_DEFINE(NO_HIDDEN_EXTERN_FUNC_IN_PIE)
fi