Re: gdb builder status (Was: Adding binutils to the GNU Toolchain buildbot on sourceware)

[Mark Wielaard <mark@klomp.org>]

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Hi Simon,

Moved to gdb-patches, now that we have an approach and concrete patch.

On Tue, May 03, 2022 at 11:41:33AM -0400, Simon Marchi wrote:
> If it's really just the diagnostic that is bogus, my preference would be
> to try to silence the diagnostic and not modify the code.
> 
> It would require adding a DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD to
> include/diagnostics.h.
> 
> I would also limit the disabling to just that arch

OK, how about the attached? Build on fedora/s390x and debian/aarch64.

Thanks,

Mark

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From 7ee5428d3bb06e5b4b8379a2a84092102a09a4ef Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mark@klomp.org>
Date: Tue, 3 May 2022 23:17:31 +0000
Subject: [PATCH] gdb: Workaround stringop-overread warning in
 debuginfod-support.c on s390x

For some reason g++ 11.2.1 on s390x produces a spurious warning for
stringop-overread in debuginfod_is_enabled for url_view. Add a new
DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD macro to suppress this warning.

include/ChangeLog:

	* diagnostics.h (DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD): New
	macro.

gdb/ChangeLog:

	* debuginfod-support.c (debuginfod_is_enabled): Use
	DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD on s390x.
---
 gdb/debuginfod-support.c | 11 +++++++++++
 include/diagnostics.h    |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/gdb/debuginfod-support.c b/gdb/debuginfod-support.c
index 4ce2e786..67e625db 100644
--- a/gdb/debuginfod-support.c
+++ b/gdb/debuginfod-support.c
@@ -17,6 +17,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include "diagnostics.h"
 #include <errno.h>
 #include "gdbsupport/scoped_fd.h"
 #include "debuginfod-support.h"
@@ -191,7 +192,17 @@ debuginfod_is_enabled ()
 	  if (off == gdb::string_view::npos)
 	    break;
 	  url_view = url_view.substr (off);
+#if defined (__s390x__)
+	  /* g++ 11.2.1 on s390x seems convinced url_view might be of
+	     SIZE_MAX length.  And so complains because the length of
+	     an array can only be PTRDIFF_MAX.  */
+	  DIAGNOSTIC_PUSH
+	  DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD
+#endif
 	  off = url_view.find_first_of (' ');
+#if defined (__s390x__)
+	  DIAGNOSTIC_POP
+#endif
 	  gdb_printf
 	    (_("  <%ps>\n"),
 	     styled_string (file_name_style.style (),
diff --git a/include/diagnostics.h b/include/diagnostics.h
index f10d0661..8bf5a3c3 100644
--- a/include/diagnostics.h
+++ b/include/diagnostics.h
@@ -76,6 +76,9 @@
 # define DIAGNOSTIC_IGNORE_STRINGOP_TRUNCATION \
   DIAGNOSTIC_IGNORE ("-Wstringop-truncation")
 
+# define DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD \
+  DIAGNOSTIC_IGNORE ("-Wstringop-overread")
+
 # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
   DIAGNOSTIC_IGNORE ("-Wformat-nonliteral")
 
@@ -108,6 +111,10 @@
 # define DIAGNOSTIC_IGNORE_STRINGOP_TRUNCATION
 #endif
 
+#ifndef DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD
+# define DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD
+#endif
+
 #ifndef DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL
 # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL
 #endif
-- 
2.34.1