[gcc(refs/users/giulianob/heads/autopar_rebase2)] [AArch64] Use __getauxval instead of getauxval in LSE detection code in libgcc

[Giuliano Belinassi]

https://gcc.gnu.org/g:9411358764b7b7af8f36a09eaf448db459afb7b4

commit 9411358764b7b7af8f36a09eaf448db459afb7b4
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date:   Wed May 6 16:20:38 2020 +0100

    [AArch64] Use __getauxval instead of getauxval in LSE detection code in libgcc
    
    This version of the fix uses __getauxval instead of getauxval.
    The whole thing is guarded simply on __gnu_linux__.
    __getauxval was introduced in 2.16 but the aarch64 port was added in 2.17 so in practice I expect all aarch64 glibcs to support __getauxval.
    
    Bootstrapped and tested on aarch64-none-linux-gnu.
    Also tested on aarch64-none-elf.
    
    2020-05-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
    
            * config/aarch64/lse-init.c (init_have_lse_atomics): Use __getauxval
            instead of getauxval.
            (AT_HWCAP): Define.
            (HWCAP_ATOMICS): Define.
            Guard detection on __gnu_linux__.

Diff:
---
 libgcc/ChangeLog                 |  8 ++++++++
 libgcc/config/aarch64/lse-init.c | 17 +++++++++--------
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 49d757f9061..8e63e43b756 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,11 @@
+2020-05-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/aarch64/lse-init.c (init_have_lse_atomics): Use __getauxval
+	instead of getauxval.
+	(AT_HWCAP): Define.
+	(HWCAP_ATOMICS): Define.
+	Guard detection on __gnu_linux__.
+
 2020-05-05  Michael Meissner  <meissner@linux.ibm.com>
 
 	* config.host: Delete changes meant for a private branch.
diff --git a/libgcc/config/aarch64/lse-init.c b/libgcc/config/aarch64/lse-init.c
index 74acef25cce..00e9ab8cd1c 100644
--- a/libgcc/config/aarch64/lse-init.c
+++ b/libgcc/config/aarch64/lse-init.c
@@ -29,19 +29,20 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 _Bool __aarch64_have_lse_atomics
   __attribute__((visibility("hidden"), nocommon));
 
-/* Disable initialization of __aarch64_have_lse_atomics during bootstrap.  */
-#if !defined(inhibit_libc) && defined(HAVE_SYS_AUXV_H)
-# include <sys/auxv.h>
+/* Gate availability of __getauxval on glibc.  All AArch64-supporting glibc
+   versions support it.  */
+#ifdef __gnu_linux__
 
-/* Disable initialization if the system headers are too old.  */
-# if defined(AT_HWCAP) && defined(HWCAP_ATOMICS)
+# define AT_HWCAP	16
+# define HWCAP_ATOMICS	(1 << 8)
+
+unsigned long int __getauxval (unsigned long int);
 
 static void __attribute__((constructor))
 init_have_lse_atomics (void)
 {
-  unsigned long hwcap = getauxval (AT_HWCAP);
+  unsigned long hwcap = __getauxval (AT_HWCAP);
   __aarch64_have_lse_atomics = (hwcap & HWCAP_ATOMICS) != 0;
 }
 
-# endif /* HWCAP */
-#endif /* inhibit_libc */
+#endif /* __gnu_linux__  */