MIPS: improve -march=native arch detection

If we cannot get info from options and cpuinfo, we try to get from:
  1. getauxval(AT_BASE_PLATFORM), introduced since Linux 5.7
  2. _MIPS_ARCH from host compiler.

mnan=2008 option is also used if __mips_nan2008__ is used.
This can fix the wrong loader usage on r5/r6 platform with
 -march=native.

gcc/ChangeLog:
	* config.gcc: set with_arch to default_mips_arch if no defined.
	* config/mips/driver-native.cc (host_detect_local_cpu):
	  try getauxval(AT_BASE_PLATFORM) and _MIPS_ARCH, too.
	  pass -mnan=2008 if __mips_nan2008__ is defined.
	* config.in: define HAVE_SYS_AUXV_H and HAVE_GETAUXVAL.
	* configure.ac: detect sys/auxv.h and getauxval.
	* configure: regenerated.

5 files changed, 38 insertions, 7 deletions

diff --git a/gcc/config.gcc b/gcc/config.gcc
index e73cb84..eec544f 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -5608,6 +5608,8 @@ case ${target} in
 		esac
 		if test x$with_arch != x; then
 			default_mips_arch=$with_arch
+		else
+			with_arch=$default_mips_arch
 		fi
 		if test x$with_abi != x; then
 			default_mips_abi=$with_abi
diff --git a/gcc/config.in b/gcc/config.in
index 6ac17be..cc217b9 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -1939,6 +1939,12 @@
 #endif
 
 
+/* Define to 1 if you have the <sys/auxv.h> header file. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_SYS_AUXV_H
+#endif
+
+
 /* Define to 1 if you have the <sys/file.h> header file. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_SYS_FILE_H
@@ -2672,3 +2678,7 @@
 #undef vfork
 #endif
 
+/* Define to 1 if you have the `getauxval' function. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_GETAUXVAL
+#endif
diff --git a/gcc/config/mips/driver-native.cc b/gcc/config/mips/driver-native.cc
index 47627f8..327ad25 100644
--- a/gcc/config/mips/driver-native.cc
+++ b/gcc/config/mips/driver-native.cc
@@ -23,6 +23,9 @@ along with GCC; see the file COPYING3.  If not see
 #include "system.h"
 #include "coretypes.h"
 #include "tm.h"
+#ifdef HAVE_SYS_AUXV_H
+#include <sys/auxv.h>
+#endif
 
 /* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
@@ -41,6 +44,7 @@ const char *
 host_detect_local_cpu (int argc, const char **argv)
 {
   const char *cpu = NULL;
+  char *ret = NULL;
   char buf[128];
   FILE *f;
   bool arch;
@@ -54,7 +58,7 @@ host_detect_local_cpu (int argc, const char **argv)
 
   f = fopen ("/proc/cpuinfo", "r");
   if (f == NULL)
-    return NULL;
+    goto fallback_cpu;
 
   while (fgets (buf, sizeof (buf), f) != NULL)
     if (startswith (buf, "cpu model"))
@@ -84,8 +88,23 @@ host_detect_local_cpu (int argc, const char **argv)
 
   fclose (f);
 
+fallback_cpu:
+#if defined (__mips_nan2008)
+  ret = reconcat (ret, " -mnan=2008 ", NULL);
+#endif
+
+#ifdef HAVE_GETAUXVAL
   if (cpu == NULL)
-    return NULL;
+    cpu = (const char *) getauxval (AT_BASE_PLATFORM);
+#endif
+
+#if defined (_MIPS_ARCH)
+  if (cpu == NULL)
+    cpu = _MIPS_ARCH;
+#endif
+
+  if (cpu)
+    ret = reconcat (ret, ret, "-m", argv[0], "=", cpu, NULL);
 
-  return concat ("-m", argv[0], "=", cpu, NULL);
+  return ret;
 }
diff --git a/gcc/configure b/gcc/configure
index ce4e185..b512580 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -9327,7 +9327,7 @@ $as_echo "#define GWINSZ_IN_SYS_IOCTL 1" >>confdefs.h
 fi
 
 for ac_header in limits.h stddef.h string.h strings.h stdlib.h time.h iconv.h \
-		 fcntl.h ftw.h unistd.h sys/file.h sys/time.h sys/mman.h \
+		 fcntl.h ftw.h unistd.h sys/auxv.h sys/file.h sys/time.h sys/mman.h \
 		 sys/resource.h sys/param.h sys/times.h sys/stat.h sys/locking.h \
 		 direct.h malloc.h langinfo.h ldfcn.h locale.h wchar.h
 do :
@@ -10622,7 +10622,7 @@ fi
 for ac_func in times clock kill getrlimit setrlimit atoq \
 	popen sysconf strsignal getrusage nl_langinfo \
 	gettimeofday mbstowcs wcswidth mmap posix_fallocate setlocale \
-	clearerr_unlocked feof_unlocked   ferror_unlocked fflush_unlocked fgetc_unlocked fgets_unlocked   fileno_unlocked fprintf_unlocked fputc_unlocked fputs_unlocked   fread_unlocked fwrite_unlocked getchar_unlocked getc_unlocked   putchar_unlocked putc_unlocked madvise mallinfo mallinfo2 fstatat
+	clearerr_unlocked feof_unlocked   ferror_unlocked fflush_unlocked fgetc_unlocked fgets_unlocked   fileno_unlocked fprintf_unlocked fputc_unlocked fputs_unlocked   fread_unlocked fwrite_unlocked getchar_unlocked getc_unlocked   putchar_unlocked putc_unlocked madvise mallinfo mallinfo2 fstatat getauxval
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_cxx_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/gcc/configure.ac b/gcc/configure.ac
index b6bafa8..e48fcbf 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -1307,7 +1307,7 @@ ACX_HEADER_STRING
 AC_HEADER_SYS_WAIT
 AC_HEADER_TIOCGWINSZ
 AC_CHECK_HEADERS(limits.h stddef.h string.h strings.h stdlib.h time.h iconv.h \
-		 fcntl.h ftw.h unistd.h sys/file.h sys/time.h sys/mman.h \
+		 fcntl.h ftw.h unistd.h sys/auxv.h sys/file.h sys/time.h sys/mman.h \
 		 sys/resource.h sys/param.h sys/times.h sys/stat.h sys/locking.h \
 		 direct.h malloc.h langinfo.h ldfcn.h locale.h wchar.h)
 
@@ -1525,7 +1525,7 @@ define(gcc_UNLOCKED_FUNCS, clearerr_unlocked feof_unlocked dnl
 AC_CHECK_FUNCS(times clock kill getrlimit setrlimit atoq \
 	popen sysconf strsignal getrusage nl_langinfo \
 	gettimeofday mbstowcs wcswidth mmap posix_fallocate setlocale \
-	gcc_UNLOCKED_FUNCS madvise mallinfo mallinfo2 fstatat)
+	gcc_UNLOCKED_FUNCS madvise mallinfo mallinfo2 fstatat getauxval)
 
 if test x$ac_cv_func_mbstowcs = xyes; then
   AC_CACHE_CHECK(whether mbstowcs works, gcc_cv_func_mbstowcs_works,