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[RFC PATCH v2 1/3] Prepare vfprintf to use __printf_fp/__printf_fphex with float128 arg

On powerpc64le, long double can currently take two formats: the same as
double (-mlong-double-64) or IBM Extended Precision (default with
-mlong-double-128 or explicitly with -mabi=ibmlongdouble).  The internal
implementation of printf-like functions is aware of these possibilites
and properly parses floating-point values from the variable arguments,
before making calls to __printf_fp and __printf_fphex.  These functions
are also aware of the format possibilites and know how to convert both
formats to string.

When library support for TS 18661-3 was added to glibc, __printf_fp and
__printf_fphex were extented with support for an additional type
(__float128/_Float128) with a different format (binary128).  Now that
powerpc64le is getting support for its third long double format, and
taking into account that this format is the same as the format of
__float128/_Float128, this patch extends __vfprintf_internal to properly
call __printf_fp and __printf_fphex with this new format.

Tested for powerpc64le (with additional patches to actually enable the
use of these preparations) and for x86_64.

	* libio/libioP.h (PRINTF_LDBL_USES_FLOAT128): New macro to be
	used as a mask for the mode argument of __vfprintf_internal.
	* stdio-common/printf-parse.h (printf_arg): New union member:
	pa_float128.
	* stdio-common/vfprintf-internal.c
	(LDBL_USES_FLOAT128): New macro.
	(PARSE_FLOAT_VA_ARG_EXTENDED): Likewise.
	(PARSE_FLOAT_VA_ARG): Likewise.
	(SETUP_FLOAT128_INFO): Likewise.
	(process_arg): Use PARSE_FLOAT_VA_ARG_EXTENDED and
	SETUP_FLOAT128_INFO.
	[__HAVE_FLOAT128_UNLIKE_LDBL] (printf_positional): Write
	floating-point value to the new union member, pa_float128.
---
 libio/libioP.h                   |  5 ++--
 stdio-common/printf-parse.h      |  3 ++
 stdio-common/vfprintf-internal.c | 62 +++++++++++++++++++++++++++++++---------
 3 files changed, 55 insertions(+), 15 deletions(-)

diff --git a/libio/libioP.h b/libio/libioP.h
index 07b60e3e26..a0353f76fe 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -687,8 +687,9 @@ extern int __vswprintf_internal (wchar_t *string, size_t maxlen,
                                  unsigned int mode_flags);
 
 /* Flags for __v*printf_internal.  */
-#define PRINTF_LDBL_IS_DBL 0x0001
-#define PRINTF_FORTIFY     0x0002
+#define PRINTF_LDBL_IS_DBL		0x0001
+#define PRINTF_FORTIFY			0x0002
+#define PRINTF_LDBL_USES_FLOAT128	0x0004
 
 extern size_t _IO_getline (FILE *,char *, size_t, int, int);
 libc_hidden_proto (_IO_getline)
diff --git a/stdio-common/printf-parse.h b/stdio-common/printf-parse.h
index e07186ec83..7f2fd56049 100644
--- a/stdio-common/printf-parse.h
+++ b/stdio-common/printf-parse.h
@@ -57,6 +57,9 @@ union printf_arg
     unsigned long long int pa_u_long_long_int;
     double pa_double;
     long double pa_long_double;
+#if __HAVE_FLOAT128_UNLIKE_LDBL
+    __float128 pa_float128;
+#endif
     const char *pa_string;
     const wchar_t *pa_wstring;
     void *pa_pointer;
diff --git a/stdio-common/vfprintf-internal.c b/stdio-common/vfprintf-internal.c
index 2d9016e83b..fb784f538c 100644
--- a/stdio-common/vfprintf-internal.c
+++ b/stdio-common/vfprintf-internal.c
@@ -68,8 +68,43 @@
     } while (0)
 #define UNBUFFERED_P(S) ((S)->_flags & _IO_UNBUFFERED)
 #define LDBL_IS_DBL (__glibc_unlikely ((mode_flags & PRINTF_LDBL_IS_DBL) != 0))
+#define LDBL_USES_FLOAT128 ((mode_flags && PRINTF_LDBL_USES_FLOAT128) == 1)
 #define DO_FORTIFY  ((mode_flags & PRINTF_FORTIFY) != 0)
 
+#if __HAVE_FLOAT128_UNLIKE_LDBL
+# define PARSE_FLOAT_VA_ARG_EXTENDED(INFO)				      \
+  if (LDBL_USES_FLOAT128)						      \
+    {									      \
+      INFO.is_binary128 = 1;						      \
+      the_arg.pa_float128 = va_arg (ap, __float128);			      \
+    }									      \
+  else									      \
+    {									      \
+      PARSE_FLOAT_VA_ARG (INFO)						      \
+    }
+#else
+# define PARSE_FLOAT_VA_ARG_EXTENDED(INFO)				      \
+  PARSE_FLOAT_VA_ARG (INFO)
+#endif
+
+#define PARSE_FLOAT_VA_ARG(INFO)					      \
+  INFO.is_binary128 = 0;						      \
+  if (is_long_double)							      \
+    the_arg.pa_long_double = va_arg (ap, long double);			      \
+  else									      \
+    the_arg.pa_double = va_arg (ap, double);
+
+#if __HAVE_FLOAT128_UNLIKE_LDBL
+# define SETUP_FLOAT128_INFO(INFO)					      \
+  if (LDBL_USES_FLOAT128)						      \
+    INFO.is_binary128 = 1;						      \
+  else									      \
+    INFO.is_binary128 = 0;
+#else
+# define SETUP_FLOAT128_INFO(INFO)					      \
+  INFO.is_binary128 = 0;
+#endif
+
 #define done_add(val) \
   do {									      \
     unsigned int _val = val;						      \
@@ -773,10 +808,7 @@ static const uint8_t jump_table[] =
 					.wide = sizeof (CHAR_T) != 1,	      \
 					.is_binary128 = 0};		      \
 									      \
-	    if (is_long_double)						      \
-	      the_arg.pa_long_double = va_arg (ap, long double);	      \
-	    else							      \
-	      the_arg.pa_double = va_arg (ap, double);			      \
+	    PARSE_FLOAT_VA_ARG_EXTENDED (info)				      \
 	    ptr = (const void *) &the_arg;				      \
 									      \
 	    function_done = __printf_fp (s, &info, &ptr);		      \
@@ -789,8 +821,7 @@ static const uint8_t jump_table[] =
 		fspec->data_arg_type = PA_DOUBLE;			      \
 		fspec->info.is_long_double = 0;				      \
 	      }								      \
-	    /* Not supported by *printf functions.  */			      \
-	    fspec->info.is_binary128 = 0;				      \
+	    SETUP_FLOAT128_INFO (fspec->info)				      \
 									      \
 	    function_done = __printf_fp (s, &fspec->info, &ptr);	      \
 	  }								      \
@@ -833,10 +864,7 @@ static const uint8_t jump_table[] =
 					.wide = sizeof (CHAR_T) != 1,	      \
 					.is_binary128 = 0};		      \
 									      \
-	    if (is_long_double)						      \
-	      the_arg.pa_long_double = va_arg (ap, long double);	      \
-	    else							      \
-	      the_arg.pa_double = va_arg (ap, double);			      \
+	    PARSE_FLOAT_VA_ARG_EXTENDED (info)				      \
 	    ptr = (const void *) &the_arg;				      \
 									      \
 	    function_done = __printf_fphex (s, &info, &ptr);		      \
@@ -846,8 +874,7 @@ static const uint8_t jump_table[] =
 	    ptr = (const void *) &args_value[fspec->data_arg];		      \
 	    if (LDBL_IS_DBL)                                            \
 	      fspec->info.is_long_double = 0;				      \
-	    /* Not supported by *printf functions.  */			      \
-	    fspec->info.is_binary128 = 0;				      \
+	    SETUP_FLOAT128_INFO (fspec->info)				      \
 									      \
 	    function_done = __printf_fphex (s, &fspec->info, &ptr);	      \
 	  }								      \
@@ -1871,6 +1898,10 @@ printf_positional (FILE *s, const CHAR_T *format, int readonly_format,
 	    args_value[cnt].pa_double = va_arg (*ap_savep, double);
 	    args_type[cnt] &= ~PA_FLAG_LONG_DOUBLE;
 	  }
+#if __HAVE_FLOAT128_UNLIKE_LDBL
+	else if (LDBL_USES_FLOAT128)
+	  args_value[cnt].pa_float128 = va_arg (*ap_savep, __float128);
+#endif
 	else
 	  args_value[cnt].pa_long_double = va_arg (*ap_savep, long double);
 	break;
@@ -1889,7 +1920,12 @@ printf_positional (FILE *s, const CHAR_T *format, int readonly_format,
 	      (args_value[cnt].pa_user, ap_savep);
 	  }
 	else
-	  args_value[cnt].pa_long_double = 0.0;
+	  {
+	    args_value[cnt].pa_long_double = 0.0;
+#if __HAVE_FLOAT128_UNLIKE_LDBL
+	    args_value[cnt].pa_float128 = 0;
+#endif
+	  }
 	break;
       case -1:
 	/* Error case.  Not all parameters appear in N$ format
-- 
2.14.4
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