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authorH.J. Lu <hjl.tools@gmail.com>2017-08-21 05:50:38 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-08-21 05:50:52 -0700
commit568ff4296c72534e49c8d9c83c33f3a0069cccc7 (patch)
treebededb41a0b181d3f4ab13868b9169819244808a
parent7c41b4a1315fc4415e468bbac94f77ecdb74f4c8 (diff)
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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.
-rw-r--r--ChangeLog8
-rw-r--r--include/libc-symbols.h16
2 files changed, 22 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index e7ffb591b1..8ff2d90bae 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 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
 	visibility in libc.a compiled with PIE.
 
diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index d6a1c260f6..fe3571af52 100644
--- 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__ */