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.

diff --git a/ChangeLog b/ChangeLog
index e7ffb591b1af7ac01749b08799fec786770fce38..8ff2d90baee942ab9172e8402c972a5a712a48cb 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2017-08-21  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.
+
 2017-08-21  H.J. Lu  <hongjiu.lu@intel.com>
 
        * include/libc-symbols.h (attribute_hidden): Enable hidden

diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index d6a1c260f6cb80aacd16c9b1b991559421419cf3..fe3571af52925f1c9cb8e2211d5914cf2ca08986 100644 (file)
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -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__ */