S390: Ifunc resolver macro for vector instructions.

This patch introduces a s390 specific ifunc resolver macro for 32/64bit,
which chooses <func>_vx with vector instructions if HWCAP_S390_VX flag
in hwcaps is set or <func>_c if not.

ChangeLog:

	* sysdeps/s390/multiarch/ifunc-resolve.h (s390_vx_libc_ifunc,
	s390_vx_libc_ifunc2): New macro function.

ChangeLog

@@ -1,3 +1,8 @@
+2015-08-26  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	* sysdeps/s390/multiarch/ifunc-resolve.h (s390_vx_libc_ifunc,
+	s390_vx_libc_ifunc2): New macro function.
+
 2015-08-26  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
 	* config.h.in (HAVE_S390_VX_ASM_SUPPORT): New macro undefine.

sysdeps/s390/multiarch/ifunc-resolve.h

@@ -73,3 +73,22 @@
     else								\
       return &__##FUNC##_default;					\
   }
+
+#define s390_vx_libc_ifunc(FUNC)		\
+  s390_vx_libc_ifunc2(FUNC, FUNC)
+
+#define s390_vx_libc_ifunc2(RESOLVERFUNC, FUNC)				\
+  /* Make the declarations of the optimized functions hidden in order
+     to prevent GOT slots being generated for them.  */			\
+  extern __typeof (FUNC) RESOLVERFUNC##_vx attribute_hidden;		\
+  extern __typeof (FUNC) RESOLVERFUNC##_c attribute_hidden;		\
+  extern void *__resolve_##RESOLVERFUNC (unsigned long int) __asm__ (#FUNC); \
+									\
+  void *__resolve_##RESOLVERFUNC (unsigned long int dl_hwcap)		\
+  {									\
+    if (dl_hwcap & HWCAP_S390_VX)					\
+      return &RESOLVERFUNC##_vx;					\
+    else								\
+      return &RESOLVERFUNC##_c;						\
+  }									\
+ __asm__ (".type " #FUNC ", %gnu_indirect_function");