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Fix testsuite build for GCC 7 -Wformat-truncation
- From: Joseph Myers <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Tue, 10 Jan 2017 14:39:25 +0000
- Subject: Fix testsuite build for GCC 7 -Wformat-truncation
- Authentication-results: sourceware.org; auth=none
This patch fixes the glibc testsuite build for GCC 7
-Wformat-truncation, newly moved out of -Wformat-length and with some
further warnings that didn't previously appear. Two tests that
previously disabled -Wformat-length are changed to disable
-Wformat-truncation instead; two others are made to disable that
option as well.
To fix the build with GCC 7 this goes on top of
<https://sourceware.org/ml/libc-alpha/2017-01/msg00149.html>,
<https://sourceware.org/ml/libc-alpha/2017-01/msg00150.html> and
<https://sourceware.org/ml/libc-alpha/2017-01/msg00151.html>, which
are all needed to fix the build of glibc itself in particular
configurations (64-bit for the first two, big-endian for the third)
and are all pending review.
Tested (compilation only) with build-many-glibcs.py for aarch64 with
GCC mainline.
2017-01-10 Joseph Myers <joseph@codesourcery.com>
* stdio-common/tst-printf.c [__GNUC_PREREQ (7, 0)]: Ignore
-Wformat-truncation instead of -Wformat-length.
* time/tst-strptime2.c (mkbuf) [__GNUC_PREREQ (7, 0)]: Likewise.
* stdio-common/tstdiomisc.c (F): Ignore -Wformat-truncation for
GCC 7.
* wcsmbs/tst-wcstof.c: Include <libc-internal.h>.
(do_test): Ignore -Wformat-truncation for GCC 7.
diff --git a/stdio-common/tst-printf.c b/stdio-common/tst-printf.c
index 74150c5..719b3eb 100644
--- a/stdio-common/tst-printf.c
+++ b/stdio-common/tst-printf.c
@@ -33,8 +33,9 @@
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
#if __GNUC_PREREQ (7, 0)
-/* Compiler warnings about format lengths should also be ignored. */
-DIAG_IGNORE_NEEDS_COMMENT (7.0, "-Wformat-length");
+/* Compiler warnings about snprintf output truncation should also be
+ ignored. */
+DIAG_IGNORE_NEEDS_COMMENT (7.0, "-Wformat-truncation");
#endif
static void rfg1 (void);
diff --git a/stdio-common/tstdiomisc.c b/stdio-common/tstdiomisc.c
index 5548a71..9c7342d 100644
--- a/stdio-common/tstdiomisc.c
+++ b/stdio-common/tstdiomisc.c
@@ -94,6 +94,14 @@ F (void)
qnanval = NAN;
+ /* The %f and %F arguments are in fact constants, but GCC is
+ prevented from seeing this (volatile is used) so it cannot tell
+ that the output is not truncated. */
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+ DIAG_IGNORE_NEEDS_COMMENT (7.0, "-Wformat-truncation");
+#endif
+
snprintf (buf, sizeof buf, "%a %A %e %E %f %F %g %G",
qnanval, qnanval, qnanval, qnanval,
qnanval, qnanval, qnanval, qnanval);
@@ -260,6 +268,8 @@ F (void)
printf ("expected L\"-inf -INF -inf -INF -inf -INF -inf -INF\", got L\"%S\"\n",
wbuf);
+ DIAG_POP_NEEDS_COMMENT;
+
return result;
}
diff --git a/time/tst-strptime2.c b/time/tst-strptime2.c
index 04f7cff..9273568 100644
--- a/time/tst-strptime2.c
+++ b/time/tst-strptime2.c
@@ -73,7 +73,7 @@ mkbuf (char *buf, bool neg, bool colon, unsigned int hhmm, size_t ndigits)
This test is explicitly using short buffers to force snprintf to truncate
the output so we ignore the warnings. */
DIAG_PUSH_NEEDS_COMMENT;
- DIAG_IGNORE_NEEDS_COMMENT (7.0, "-Wformat-length");
+ DIAG_IGNORE_NEEDS_COMMENT (7.0, "-Wformat-truncation");
#endif
if (colon)
snprintf (buf + i, ndigits + 2, "%02u:%02u", hh, mm);
diff --git a/wcsmbs/tst-wcstof.c b/wcsmbs/tst-wcstof.c
index 576a58c..861f659 100644
--- a/wcsmbs/tst-wcstof.c
+++ b/wcsmbs/tst-wcstof.c
@@ -3,6 +3,7 @@
#include <stdio.h>
#include <string.h>
#include <wctype.h>
+#include <libc-internal.h>
static int
do_test (void)
@@ -14,7 +15,14 @@ do_test (void)
tmp[1] = '1';
tmp[2] = 0;
+ /* GCC does not know the result of wcstof so cannot see that the
+ snprintf output is not truncated. */
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+ DIAG_IGNORE_NEEDS_COMMENT (7.0, "-Wformat-truncation");
+#endif
snprintf (buf, 100, "%S = %f", tmp, wcstof (tmp, NULL));
+ DIAG_POP_NEEDS_COMMENT;
printf ("\"%s\" -> %s\n", buf,
strcmp (buf, "81 = 81.000000") == 0 ? "okay" : "buggy");
result |= strcmp (buf, "81 = 81.000000") != 0;
--
Joseph S. Myers
joseph@codesourcery.com