RFC: powerpc64le: Enable support for IEEE long double gabriel/powerpc-ieee128-printscan

Not for glibc-2.31 - Do not commit!

No changes since v3.

Changes since v2:

  - Added definition of LDBL_IBM128_COMPAT_VERSION and
    LDBL_IBM128_VERSION (moved from a previous commit).

Changes since v1:

  - Use __LONG_DOUBLE_USES_FLOAT128 directly.

-- 8< --
On platforms where long double may have two different formats, i.e.: the
same format as double (64-bits) or something else (128-bits), building
with -mlong-double-128 is the default and function calls in the user
program match the name of the function in Glibc.  When building with
-mlong-double-64, Glibc installed headers redirect such calls to the
appropriate function.

This patch adds similar redirections to be used by user code builds in
IEEE long double mode (-mabi=ieeelongdouble).  It also skips some uses
of libc_hidden_proto in internal headers, because they also produce
redirections, causing a redirection conflict.

PS: Missing NEWS entry.

2 files changed, 39 insertions, 3 deletions

diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 467dbd9547..d449628bdb 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -452,7 +452,37 @@
 #include <bits/wordsize.h>
 #include <bits/long-double.h>
 
-#if defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
+#if __LONG_DOUBLE_USES_FLOAT128 == 1
+# ifdef __REDIRECT
+
+/* Alias name defined automatically.  */
+#  define __LDBL_REDIR(name, proto) ... unused__ldbl_redir
+#  define __LDBL_REDIR_DECL(name) \
+  extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
+
+/* Alias name defined automatically, with leading underscores.  */
+#  define __LDBL_REDIR2_DECL(name) \
+  extern __typeof (__##name) __##name \
+    __asm (__ASMNAME ("__" #name "ieee128"));
+
+/* Alias name defined manually.  */
+#  define __LDBL_REDIR1(name, proto, alias) ... unused__ldbl_redir1
+#  define __LDBL_REDIR1_DECL(name, alias) \
+  extern __typeof (name) name __asm (__ASMNAME (#alias));
+
+#  define __LDBL_REDIR1_NTH(name, proto, alias) \
+  __REDIRECT_NTH (name, proto, alias)
+#  define __REDIRECT_NTH_LDBL(name, proto, alias) \
+  __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128)
+
+/* Unused.  */
+#  define __REDIRECT_LDBL(name, proto, alias) ... unused__redirect_ldbl
+#  define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth
+
+# else
+_Static_assert (0, "IEEE 128-bits long double requires redirection on this platform");
+# endif
+#elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
 # define __LDBL_COMPAT 1
 # ifdef __REDIRECT
 #  define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias)
@@ -461,6 +491,8 @@
 #  define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias)
 #  define __LDBL_REDIR_NTH(name, proto) \
   __LDBL_REDIR1_NTH (name, proto, __nldbl_##name)
+#  define __LDBL_REDIR2_DECL(name) \
+  extern __typeof (__##name) __##name __asm (__ASMNAME ("__nldbl___" #name));
 #  define __LDBL_REDIR1_DECL(name, alias) \
   extern __typeof (name) name __asm (__ASMNAME (#alias));
 #  define __LDBL_REDIR_DECL(name) \
@@ -471,11 +503,13 @@
   __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias)
 # endif
 #endif
-#if !defined __LDBL_COMPAT || !defined __REDIRECT
+#if (!defined __LDBL_COMPAT && __LONG_DOUBLE_USES_FLOAT128 == 0) \
+    || !defined __REDIRECT
 # define __LDBL_REDIR1(name, proto, alias) name proto
 # define __LDBL_REDIR(name, proto) name proto
 # define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW
 # define __LDBL_REDIR_NTH(name, proto) name proto __THROW
+# define __LDBL_REDIR2_DECL(name)
 # define __LDBL_REDIR_DECL(name)
 # ifdef __REDIRECT
 #  define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias)
diff --git a/misc/sys/syslog.h b/misc/sys/syslog.h
index ee01478c4b..c000b8e915 100644
--- a/misc/sys/syslog.h
+++ b/misc/sys/syslog.h
@@ -206,7 +206,9 @@ extern void vsyslog (int __pri, const char *__fmt, __gnuc_va_list __ap)
 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
 # include <bits/syslog.h>
 #endif
-#ifdef __LDBL_COMPAT
+
+#include <bits/floatn.h>
+#if defined __LDBL_COMPAT || __LONG_DOUBLE_USES_FLOAT128 == 1
 # include <bits/syslog-ldbl.h>
 #endif