Add hidden visibility to internal function prototypes

Add hidden visibility to internal function prototypes to allow direct
access to internal functions within libc.a without using GOT when the
compiler defaults to -fPIE.

Size comparison of elf/ldconfig when the compiler defaults to -fPIE:

On x86-64:
        text	   data	    bss	    dec	    hex
Before: 619646	  20132	   5488	 645266	  9d892
After : 619502	  20132	   5488	 645122	  9d802
On i686:
        text	   data	    bss	    dec	    hex
Before: 550333	  10748	   3060	 564141	  89bad
After : 546453	  10732	   3060	 560245	  88c75

	* include/libc-symbols.h (__hidden_proto_hiddenattr): New for
	building libc.a.
	(hidden_proto): Likewise.
	(hidden_tls_proto): Likewise.
	(__hidden_proto): Likewise.

(Reapplied after the revert in df1deda60050cc8a68156cf6c81ad42363647a29.)
This commit is contained in:
H.J. Lu 2017-08-22 13:49:14 +02:00 committed by Florian Weimer
parent a4d57b7947
commit 8d2ec55329
2 changed files with 22 additions and 2 deletions

View File

@ -1,3 +1,11 @@
2017-08-22 H.J. Lu <hongjiu.lu@intel.com>
* include/libc-symbols.h (__hidden_proto_hiddenattr): New for
building libc.a.
(hidden_proto): Likewise.
(hidden_tls_proto): Likewise.
(__hidden_proto): Likewise.
2017-08-22 Florian Weimer <fweimer@redhat.com>
math: Statically link tests of internal functionality.

View File

@ -513,8 +513,20 @@ for linking")
# endif
#else
# ifndef __ASSEMBLER__
# define hidden_proto(name, attrs...)
# define hidden_tls_proto(name, attrs...)
# if !defined SHARED && IS_IN (libc) && !defined LIBC_NONSHARED \
&& !defined NO_HIDDEN
# define __hidden_proto_hiddenattr(attrs...) \
__attribute__ ((visibility ("hidden"), ##attrs))
# define hidden_proto(name, attrs...) \
__hidden_proto (name, , name, ##attrs)
# define hidden_tls_proto(name, attrs...) \
__hidden_proto (name, __thread, name, ##attrs)
# define __hidden_proto(name, thread, internal, attrs...) \
extern thread __typeof (name) name __hidden_proto_hiddenattr (attrs);
# else
# define hidden_proto(name, attrs...)
# define hidden_tls_proto(name, attrs...)
# endif
# else
# define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
# endif /* Not __ASSEMBLER__ */