math: add LDBL_CLASSIFY_COMPAT support

If a platform does not define "long-double-fcts = yes" in its
Makefiles and it does define __NO_LONG_DOUBLE_MATH in its installed
headers, it will currently create exported symbols for __finitel,
__isinfl, and __isnanl that can't be reached from userspace by
correct use of the finite(), isinf(), or isnan() macros in <math.h>.

To avoid this situation, by default for such platforms we now no
longer export these symbols, thus causing appropriate link-time
errors.  However, for platforms that previously exported these
symbols, we continue to do so as compat symbols; this is enabled
by adding LDBL_CLASSIFY_COMPAT to math_private.h for the platform.

For tile, remove the now-unnecessary exports of those functions from
libc and libm.

1 files changed, 9 insertions, 1 deletions

diff --git a/sysdeps/ieee754/dbl-64/s_finite.c b/sysdeps/ieee754/dbl-64/s_finite.c
index 2b0ed504f9..b71ae12ea4 100644
--- a/sysdeps/ieee754/dbl-64/s_finite.c
+++ b/sysdeps/ieee754/dbl-64/s_finite.c
@@ -21,6 +21,7 @@ static char rcsid[] = "$NetBSD: s_finite.c,v 1.8 1995/05/10 20:47:17 jtc Exp $";
 
 #include <math.h>
 #include <math_private.h>
+#include <shlib-compat.h>
 
 #undef __finite
 
@@ -37,6 +38,13 @@ int FINITE(double x)
 hidden_def (__finite)
 weak_alias (__finite, finite)
 #ifdef NO_LONG_DOUBLE
-strong_alias (__finite, __finitel)
+# ifdef LDBL_CLASSIFY_COMPAT
+#  if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
+compat_symbol (libc, __finite, __finitel, GLIBC_2_0);
+#  endif
+#  if SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_23)
+compat_symbol (libm, __finite, __finitel, GLIBC_2_0);
+#  endif
+# endif
 weak_alias (__finite, finitel)
 #endif