ldbl-128ibm-compat: Add printf_size

Since the addition of the _Float128 API, strfromf128 and printf_size use
__printf_fp to print _Float128 values.  This is achieved by setting the
'is_binary128' member of the 'printf_info' structure to one.  Now that
the format of long double on powerpc64le is getting a third option, this
mechanism is reused for long double values that have binary128 format
(i.e.: when -mabi=ieeelongdouble).

This patch adds __printf_sizeieee128 as an exported symbol, but doesn't
provide redirections from printf_size, yet.  All redirections will be
installed in a future commit, once all other functions that print or
read long double values with binary128 format are ready.  In
__printf_fp, when 'is_binary128' is one, the floating-point argument is
treated as if it was of _Float128 type, regardless of the value of
'is_long_double', thus __printf_sizeieee128 sets 'is_binary128' to the
same value of 'is_long_double'.  Otherwise, double values would not be
printed correctly.

Tested for powerpc64le.

3 files changed, 97 insertions, 2 deletions

diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 738a3cead0..96bd7c303a 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -63,13 +63,14 @@ tests := tstscanf test_rdwr test-popen tstgetln test-fseek \
 	 tst-vfprintf-mbs-prec \
 	 tst-scanf-round \
 
-test-srcs = tst-unbputc tst-printf
+test-srcs = tst-unbputc tst-printf tst-printfsz-islongdouble
 
 ifeq ($(run-built-tests),yes)
 tests-special += $(objpfx)tst-unbputc.out $(objpfx)tst-printf.out \
 		 $(objpfx)tst-printf-bz18872-mem.out \
 		 $(objpfx)tst-setvbuf1-cmp.out \
-		 $(objpfx)tst-vfprintf-width-prec-mem.out
+		 $(objpfx)tst-vfprintf-width-prec-mem.out \
+		 $(objpfx)tst-printfsz-islongdouble.out
 generated += tst-printf-bz18872.c tst-printf-bz18872.mtrace \
 	     tst-printf-bz18872-mem.out \
 	     tst-vfprintf-width-prec.mtrace tst-vfprintf-width-prec-mem.out
@@ -103,6 +104,11 @@ $(objpfx)tst-printf.out: tst-printf.sh $(objpfx)tst-printf
 	$(SHELL) $< $(common-objpfx) '$(test-program-prefix)' > $@; \
 	$(evaluate-test)
 
+$(objpfx)tst-printfsz-islongdouble.out: \
+  tst-printfsz-islongdouble.sh $(objpfx)tst-printfsz-islongdouble
+	$(SHELL) $^ '$(test-program-prefix)' $@; \
+	$(evaluate-test)
+
 # We generate this source because it requires a printf invocation with
 # 10K arguments.
 $(objpfx)tst-printf-bz18872.c: tst-printf-bz18872.sh
diff --git a/stdio-common/tst-printfsz-islongdouble.c b/stdio-common/tst-printfsz-islongdouble.c
new file mode 100644
index 0000000000..a6a534bb3d
--- /dev/null
+++ b/stdio-common/tst-printfsz-islongdouble.c
@@ -0,0 +1,51 @@
+/* Test for the behaviour of 'is_long_double' in printf_size.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <printf.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+  double d = 2000;
+  double *dptr = &d;
+  long double ld = 4000;
+  long double *ldptr = & ld;
+  struct printf_info info;
+
+  memset (&info, 0, sizeof (info));
+  info.spec = L'f';
+
+  /* Print a value with double type.  */
+  printf_size (stdout, &info, (void *) &dptr);
+
+  /* Printf a value with long double type.  */
+  info.is_long_double = 1;
+  printf_size (stdout, &info, (void *) &ldptr);
+
+  /* Setting both 'is_long_double' and 'is_binary128' to one is out of
+     the scope of this test, because such configuration is only valid
+     when _Float128 and long double are ABI-distinct (which is not
+     always true in this arch-independent test).  */
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/stdio-common/tst-printfsz-islongdouble.sh b/stdio-common/tst-printfsz-islongdouble.sh
new file mode 100644
index 0000000000..6eda634844
--- /dev/null
+++ b/stdio-common/tst-printfsz-islongdouble.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+# Test for the behaviour of 'is_binary128' in printf_size.
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+set -e
+
+test_program=$1; shift
+test_program_prefix=$1; shift
+test_program_output=$1; shift
+
+status=0
+
+${test_program_prefix} \
+  ${test_program} \
+  > ${test_program_output} || status=1
+
+echo -n "2k4k" | cmp - ${test_program_output} > /dev/null 2>&1 ||
+{
+  status=1
+  echo "*** output comparison failed"
+}
+
+exit $status