ldbl-128ibm-compat: PLT redirects for using ldbl redirects internally

Tweak the PLT bypass magic when building glibc with long double
redirects.  This is made more difficult by the fact we only get
one chance to redirect functions.  This happens via the public
headers.

There are roughly three classes of redirect we need to attend to
today:

 1. Simple redirects, redirected via cdef macro overrides and
    and new libc_hidden_ldbl_proto macro.
 2. Internal usage of internal API, e.g __snprintf, which has
    no direct analogue.  This is bypassed directly on case-by-
    case basis.
 3. Double redirects, e.g sscanf and related.  These require
    a heavier handed approach of macro renaming to existing
    symbols.

Most simple redirects are handled via 1.  Ideally, the libc_*
macro would live in libc-symbols.h, but in practice the macros
needed for it to do anything useful live in cdefs.h, so they
are defined in the local override.

Notably, the internal name of the asprintf generated for ieee ldbl
redirects is renamed to work with internal prefixed usage.

This resolves the local plt usage introduced when building glibc
with ldbl == ieee128 on ppc64le.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>

diff --git a/include/err.h b/include/err.h
index 7c05cd1dbb2134850dfb6514dbfb13f5374ed012..b9b7516287b7ae003b3c72b8a10554c1795e6fc9 100644 (file)
--- a/include/err.h
+++ b/include/err.h
@@ -12,12 +12,12 @@ __vwarn_internal (const char *format, __gnuc_va_list ap,
 
 # ifndef _ISOMAC
 
-libc_hidden_proto (warn)
-libc_hidden_proto (warnx)
-libc_hidden_proto (vwarn)
-libc_hidden_proto (vwarnx)
-libc_hidden_proto (verr)
-libc_hidden_proto (verrx)
+libc_hidden_ldbl_proto (warn)
+libc_hidden_ldbl_proto (warnx)
+libc_hidden_ldbl_proto (vwarn)
+libc_hidden_ldbl_proto (vwarnx)
+libc_hidden_ldbl_proto (verr)
+libc_hidden_ldbl_proto (verrx)
 
 # endif /* !_ISOMAC */
 #endif /* err.h */

diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index b0b75a087ee02c9ea3ba347bc70a5a324fb32d96..3555cb6f3d74d4bd2ab85ef8921acd57d2774688 100644 (file)
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -885,6 +885,8 @@ for linking")
 #define libc_hidden_builtin_def(name) libc_hidden_def (name)
 #define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
 #define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
+
+#define libc_hidden_ldbl_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
 #ifdef __ASSEMBLER__
 # define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
 #endif

diff --git a/include/stdio.h b/include/stdio.h
index dffa7765dd66a2bd830124e3adea909d97ba9e41..6718af4108dd9415133c8ed6693e0a00ff36b2b4 100644 (file)
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -9,13 +9,24 @@
 
 /* Now define the internal interfaces.  */
 
+/*  Some libc_hidden_ldbl_proto's do not map to a unique symbol when
+    redirecting ldouble to _Float128 variants.  We can therefore safely
+    directly alias them to their internal name.  */
+# if __LONG_DOUBLE_USES_FLOAT128 == 1 && IS_IN (libc)
+#  define stdio_hidden_ldbl_proto(p, f) \
+  extern __typeof (p ## f) p ## f __asm (__ASMNAME ("___ieee128_" #f));
+# elif __LONG_DOUBLE_USES_FLOAT128 == 1
+#  define stdio_hidden_ldbl_proto(p,f) __LDBL_REDIR1_DECL (p ## f, p ## f ## ieee128)
+# else
+#  define stdio_hidden_ldbl_proto(p,f) libc_hidden_proto (p ## f)
+# endif
+
 extern int __fcloseall (void) attribute_hidden;
 extern int __snprintf (char *__restrict __s, size_t __maxlen,
                       const char *__restrict __format, ...)
      __attribute__ ((__format__ (__printf__, 3, 4)));
-#  if __LONG_DOUBLE_USES_FLOAT128 == 0
-libc_hidden_proto (__snprintf)
-#  endif
+stdio_hidden_ldbl_proto (__, snprintf)
+
 extern int __vfscanf (FILE *__restrict __s,
                      const char *__restrict __format,
                      __gnuc_va_list __arg)
@@ -66,6 +77,7 @@ extern int __isoc99_vscanf (const char *__restrict __format,
 extern int __isoc99_vsscanf (const char *__restrict __s,
                             const char *__restrict __format,
                             __gnuc_va_list __arg) __THROW;
+
 libc_hidden_proto (__isoc99_sscanf)
 libc_hidden_proto (__isoc99_vsscanf)
 libc_hidden_proto (__isoc99_vfscanf)
@@ -74,12 +86,25 @@ libc_hidden_proto (__isoc99_vfscanf)
    Unfortunately, symbol redirection is not transitive, so the
    __REDIRECT in the public header does not link up with the above
    libc_hidden_proto.  Bridge the gap with a macro.  */
-#  if !__GLIBC_USE (DEPRECATED_SCANF) \
-      && __LONG_DOUBLE_USES_FLOAT128 == 0
+#  if !__GLIBC_USE (DEPRECATED_SCANF)
 #   undef sscanf
 #   define sscanf __isoc99_sscanf
 #  endif
 
+#  if __LONG_DOUBLE_USES_FLOAT128 == 1  && IS_IN (libc)
+/* These are implemented as redirects to other public API.
+   Therefore, the usual redirection fails to avoid PLT.  */
+extern __typeof (__isoc99_sscanf) ___ieee128_isoc99_sscanf __THROW;
+extern __typeof (__isoc99_vsscanf) ___ieee128_isoc99_vsscanf __THROW;
+extern __typeof (__isoc99_vfscanf) ___ieee128_isoc99_vfscanf __THROW;
+libc_hidden_proto (___ieee128_isoc99_sscanf)
+libc_hidden_proto (___ieee128_isoc99_vsscanf)
+libc_hidden_proto (___ieee128_isoc99_vfscanf)
+#define __isoc99_sscanf ___ieee128_isoc99_sscanf
+#define __isoc99_vsscanf ___ieee128_isoc99_vsscanf
+#define __isoc99_vfscanf ___ieee128_isoc99_vfscanf
+#  endif
+
 /* Prototypes for compatibility functions.  */
 extern FILE *__new_tmpfile (void);
 extern FILE *__old_tmpfile (void);
@@ -153,9 +178,8 @@ libc_hidden_proto (__libc_readline_unlocked);
 extern const char *const _sys_errlist_internal[] attribute_hidden;
 extern int _sys_nerr_internal attribute_hidden;
 
-#if __LONG_DOUBLE_USES_FLOAT128 == 0
-libc_hidden_proto (__asprintf)
-#endif
+libc_hidden_ldbl_proto (__asprintf)
+
 #  if IS_IN (libc)
 extern FILE *_IO_new_fopen (const char*, const char*);
 #   define fopen(fname, mode) _IO_new_fopen (fname, mode)
@@ -178,13 +202,11 @@ extern int _IO_new_fgetpos (FILE *, __fpos_t *);
 
 extern __typeof (dprintf) __dprintf
      __attribute__ ((__format__ (__printf__, 2, 3)));
-libc_hidden_proto (__dprintf)
-#if __LONG_DOUBLE_USES_FLOAT128 == 0
-libc_hidden_proto (dprintf)
-libc_hidden_proto (fprintf)
-libc_hidden_proto (vfprintf)
-libc_hidden_proto (sprintf)
-#endif
+stdio_hidden_ldbl_proto (__, dprintf)
+libc_hidden_ldbl_proto (dprintf)
+libc_hidden_ldbl_proto (fprintf)
+libc_hidden_ldbl_proto (vfprintf)
+libc_hidden_ldbl_proto (sprintf)
 libc_hidden_proto (fwrite)
 libc_hidden_proto (perror)
 libc_hidden_proto (remove)

diff --git a/include/sys/cdefs.h b/include/sys/cdefs.h
index 524fe57a25c8040d48b5b53e3143c081f4b8690d..9f44ac5a0a541ea5a2de24490f63ec672724995b 100644 (file)
--- a/include/sys/cdefs.h
+++ b/include/sys/cdefs.h
@@ -13,6 +13,26 @@ extern void __chk_fail (void) __attribute__ ((__noreturn__));
 libc_hidden_proto (__chk_fail)
 rtld_hidden_proto (__chk_fail)
 
+/* If we are using redirects internally to support long double,
+   we need to tweak some macros to ensure the PLT bypass tricks
+   continue to work in libc. */
+#if __LONG_DOUBLE_USES_FLOAT128 == 1 && IS_IN (libc) && defined SHARED
+
+# undef __LDBL_REDIR_DECL
+# define __LDBL_REDIR_DECL(func) \
+   extern __typeof(func) func __asm (__ASMNAME ("__GI____ieee128_" #func));
+
+# undef libc_hidden_ldbl_proto
+# define libc_hidden_ldbl_proto(func, attrs...) \
+   extern __typeof(func) ___ieee128_ ## func; \
+   libc_hidden_proto (___ieee128_ ## func, ##attrs);
+
+# undef __LDBL_REDIR2_DECL
+# define __LDBL_REDIR2_DECL(func) \
+   extern __typeof(__ ## func) __ ## func __asm (__ASMNAME ("__GI____ieee128___" #func));
+
 #endif
 
+#endif /* !defined _ISOMAC */
+
 #endif

diff --git a/include/sys/syslog.h b/include/sys/syslog.h
index 89d3479ebc8d58f148d4b7a305e8aff3695ba74b..44422eab13ed357178243a030d0d3c0b21b56c93 100644 (file)
--- a/include/sys/syslog.h
+++ b/include/sys/syslog.h
@@ -3,7 +3,7 @@
 #include <misc/sys/syslog.h>
 #ifndef _ISOMAC
 
-libc_hidden_proto (syslog)
+libc_hidden_ldbl_proto (syslog)
 
 /* __vsyslog_internal uses the same mode_flags bits as
    __v*printf_internal; see libio/libioP.h.  */

diff --git a/include/wchar.h b/include/wchar.h
index c792b3894370145849b9f36b8ca15ff6c731246e..617906eb14cd07307b41b6fe657f89e00fcb67ea 100644 (file)
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -64,7 +64,7 @@ libc_hidden_proto (__wcstoul_internal)
 libc_hidden_proto (__wcstoull_internal)
 libc_hidden_proto (wcstof)
 libc_hidden_proto (wcstod)
-libc_hidden_proto (wcstold)
+libc_hidden_ldbl_proto (wcstold)
 libc_hidden_proto (wcstol)
 libc_hidden_proto (wcstoll)
 libc_hidden_proto (wcstoul)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-asprintf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-asprintf.c
index 68cafbb2fac8e719aea9e2a7af51101de0c41be3..2a6ed2f8131feb35d663d472d3dbede95ce83361 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-asprintf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-asprintf.c
@@ -20,7 +20,7 @@
 #include <libio/libioP.h>
 
 extern int
-___ieee128_asprintf (char **string_ptr, const char *format, ...)
+___ieee128___asprintf (char **string_ptr, const char *format, ...)
 {
   va_list ap;
   int done;
@@ -32,4 +32,5 @@ ___ieee128_asprintf (char **string_ptr, const char *format, ...)
 
   return done;
 }
-strong_alias (___ieee128_asprintf, __asprintfieee128)
+hidden_def (___ieee128___asprintf)
+strong_alias (___ieee128___asprintf, __asprintfieee128)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-dprintf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-dprintf.c
index 9dc65309bdc59c5a30f52aad7a5a1d9121b2f1a8..87440c9850033e164d89c6bf88c43c5af964429d 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-dprintf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-dprintf.c
@@ -32,3 +32,4 @@ ___ieee128_dprintf (int d, const char *format, ...)
   return done;
 }
 strong_alias (___ieee128_dprintf, __dprintfieee128)
+hidden_def (___ieee128_dprintf);

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-err.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-err.c
index eae071b9c402d209b176a5f174e06fc51a87c72a..f81d3edcbf702dc3bb64b0986f21ebc02c6e9ccd 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-err.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-err.c
@@ -91,3 +91,10 @@ IEEE128_DECL (errx) (int status, const char *format, ...)
   VA (verrx (status, format, ap))
 }
 IEEE128_ALIAS (errx)
+
+hidden_def (___ieee128_warn)
+hidden_def (___ieee128_warnx)
+hidden_def (___ieee128_vwarn)
+hidden_def (___ieee128_vwarnx)
+hidden_def (___ieee128_verr)
+hidden_def (___ieee128_verrx)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-fprintf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-fprintf.c
index e1c989643e24a37d8d0fb4f467f5d2497ce0f6c6..b05e6f1bc620453c0ced38defaf70eee9790e213 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-fprintf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-fprintf.c
@@ -32,3 +32,4 @@ ___ieee128_fprintf (FILE *fp, const char *format, ...)
   return done;
 }
 strong_alias (___ieee128_fprintf, __fprintfieee128)
+hidden_def (___ieee128_fprintf)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_sscanf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_sscanf.c
index bfc7270a7875df3c820c833c9a711f37e57df164..cd1c9fa3331314081c43279b21b4e68e37eeb512 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_sscanf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_sscanf.c
@@ -37,3 +37,4 @@ ___ieee128_isoc99_sscanf (const char *string, const char *format, ...)
   return done;
 }
 strong_alias (___ieee128_isoc99_sscanf, __isoc99_sscanfieee128)
+hidden_def (___ieee128_isoc99_sscanf)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vfscanf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vfscanf.c
index b561fa304457e119f49db0221a6074a106969af0..2a11f49ea6fdbe8cbef9d5a1beeaf2fa17b2d901 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vfscanf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vfscanf.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <libio/libioP.h>
+#include <stdio.h>
 
 extern int
 ___ieee128_isoc99_vfscanf (FILE *fp, const char *format, va_list ap)
@@ -25,3 +26,4 @@ ___ieee128_isoc99_vfscanf (FILE *fp, const char *format, va_list ap)
   return __vfscanf_internal (fp, format, ap, mode_flags);
 }
 strong_alias (___ieee128_isoc99_vfscanf, __isoc99_vfscanfieee128)
+hidden_def (___ieee128_isoc99_vfscanf)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vsscanf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vsscanf.c
index bef6ebcce097caf66a8ae4cab526416bfaa05f91..d976cdbe1fc8b269266d945c386bdd619c43590b 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vsscanf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-isoc99_vsscanf.c
@@ -28,3 +28,4 @@ ___ieee128_isoc99_vsscanf (const char *string, const char *format, va_list ap)
   return __vfscanf_internal (fp, format, ap, mode_flags);
 }
 strong_alias (___ieee128_isoc99_vsscanf, __isoc99_vsscanfieee128)
+hidden_def (___ieee128_isoc99_vsscanf)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-sprintf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-sprintf.c
index 52088cd5761abb414a8eacae6bdfda868b2f7b55..690dc3abf1c7f51c1e4dc0679f23d3a457f95d31 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-sprintf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-sprintf.c
@@ -33,3 +33,4 @@ ___ieee128_sprintf (char *s, const char *format, ...)
   return done;
 }
 strong_alias (___ieee128_sprintf, __sprintfieee128)
+hidden_def (___ieee128_sprintf)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-syslog.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-syslog.c
index 914f24aebd213a2abf6b38adaab5fc20a9bfd530..4af546326cf1fe8127173eb3b6f6bc2af1176169 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-syslog.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-syslog.c
@@ -30,6 +30,7 @@ ___ieee128_syslog (int pri, const char *fmt, ...)
   va_end (ap);
 }
 strong_alias (___ieee128_syslog, __syslogieee128)
+hidden_def (___ieee128_syslog)
 
 void
 ___ieee128_vsyslog (int pri, const char *fmt, va_list ap)

diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-vfprintf.c b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-vfprintf.c
index 234cd9de8d3a36739365afea577c4e8032da1542..b407eae9691e320c1f020f7253c1a587d3e51e0b 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-vfprintf.c
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/ieee128-vfprintf.c
@@ -24,3 +24,4 @@ ___ieee128_vfprintf (FILE *fp, const char *format, va_list ap)
   return __vfprintf_internal (fp, format, ap, PRINTF_LDBL_USES_FLOAT128);
 }
 strong_alias (___ieee128_vfprintf, __vfprintfieee128)
+hidden_def (___ieee128_vfprintf)

diff --git a/sysdeps/ieee754/ldbl-128ibm/include/bits/iscanonical.h b/sysdeps/ieee754/ldbl-128ibm/include/bits/iscanonical.h
index bee080bd29e64b2dd55c33f663f92f9e3febdb86..8cbd6f74bfdf4be6d6a9af1ea11c7666657860b1 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm/include/bits/iscanonical.h
+++ b/sysdeps/ieee754/ldbl-128ibm/include/bits/iscanonical.h
@@ -1,5 +1,5 @@
 #include_next <bits/iscanonical.h>
 
-#ifndef _ISOMAC
+#if !defined _ISOMAC && (__LONG_DOUBLE_USES_FLOAT128 == 0)
 libm_hidden_proto (__iscanonicall)
 #endif