Remove the error handling wrapper from log2

Introduce new log2 symbol version that doesn't do SVID compatible error
handling.  The standard errno and fp exception based error handling is
inline in the new code and does not have significant overhead.

The wrapper is disabled for sysdeps/ieee754/dbl-64 by using empty
w_log2.c and enabled for targets with their own log2 implementation by
including math/w_log2.c.

The compatibility symbol version still uses the wrapper with SVID error
handling around the new code.  There is no new symbol version nor
compatibility code on !LIBM_SVID_COMPAT targets (e.g. riscv).

On targets where previously log2l was an alias of log2, now it points to
the compatibility symbol with the wrapper, because it still need the
SVID compatible error handling.  This affects NO_LONG_DOUBLE (e.g. arm)
and LONG_DOUBLE_COMPAT (e.g. alpha) targets as well.

The __log2_finite symbol is now an alias of log2.  Both __log2_finite
and log2 set errno and thus not const functions.

The ia64 asm is changed so the compat and new symbol versions map to the
same address.

Tested with build-many-glibcs.py.

	* math/Versions (GLIBC_2.29): Add log2.
	* math/w_log2_compat.c (__log2_compat): Change to versioned compat
	symbol.
	* math/w_log2.c: New file.
	* sysdeps/i386/fpu/w_log2.c: New file.
	* sysdeps/ia64/fpu/e_log2.S: Add versioned symbols.
	* sysdeps/ieee754/dbl-64/e_log2.c (__ieee754_log2): Rename to __log2
	and add necessary aliases.
	* sysdeps/ieee754/dbl-64/w_log2.c: New file.
	* sysdeps/m68k/m680x0/fpu/w_log2.c: New file.
	* sysdeps/mach/hurd/i386/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/nios2/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist: Update.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Update.

3 files changed, 26 insertions, 4 deletions

diff --git a/math/Versions b/math/Versions
index 87aa6590ed..a887602f2f 100644
--- a/math/Versions
+++ b/math/Versions
@@ -577,6 +577,6 @@ libm {
   }
   GLIBC_2.29 {
     # No SVID compatible error handling.
-    exp; exp2; log;
+    exp; exp2; log; log2;
   }
 }
diff --git a/math/w_log2.c b/math/w_log2.c
new file mode 100644
index 0000000000..148d5d48e1
--- /dev/null
+++ b/math/w_log2.c
@@ -0,0 +1,8 @@
+#include <math-type-macros-double.h>
+#undef __USE_WRAPPER_TEMPLATE
+#define __USE_WRAPPER_TEMPLATE 1
+#undef declare_mgen_alias
+#define declare_mgen_alias(a, b)
+#include <w_log2_template.c>
+versioned_symbol (libm, __log2, log2, GLIBC_2_29);
+libm_alias_double_other (__log2, log2)
diff --git a/math/w_log2_compat.c b/math/w_log2_compat.c
index 61e7170ae1..4459ce275f 100644
--- a/math/w_log2_compat.c
+++ b/math/w_log2_compat.c
@@ -23,10 +23,12 @@
 #include <libm-alias-double.h>
 
 
-#if LIBM_SVID_COMPAT
+#if LIBM_SVID_COMPAT && (SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29) \
+			 || defined NO_LONG_DOUBLE \
+			 || defined LONG_DOUBLE_COMPAT)
 /* wrapper log2(x) */
 double
-__log2 (double x)
+__log2_compat (double x)
 {
   if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_)
     {
@@ -44,5 +46,17 @@ __log2 (double x)
 
   return  __ieee754_log2 (x);
 }
-libm_alias_double (__log2, log2)
+# if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29)
+compat_symbol (libm, __log2_compat, log2, GLIBC_2_1);
+# endif
+# ifdef NO_LONG_DOUBLE
+weak_alias (__log2_compat, log2l)
+# endif
+# ifdef LONG_DOUBLE_COMPAT
+/* Work around gas bug "multiple versions for symbol".  */
+weak_alias (__log2_compat, __log2_compat_alias)
+
+LONG_DOUBLE_COMPAT_CHOOSE_libm_log2l (
+  compat_symbol (libm, __log2_compat_alias, log2l, FIRST_VERSION_libm_log2l), );
+# endif
 #endif