Fwd: [committed][gdb/build] Fix build for gcc < 11

[Tom de Vries]

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-------- Forwarded Message --------
Subject: [committed][gdb/build] Fix build for gcc < 11
Date: Wed, 15 Jun 2022 09:03:32 +0200
From: Tom de Vries <tdevries@suse.de>
To: gcc-patches@gcc.gnu.org

Hi,

When building trunk on openSUSE Leap 15.3 with system gcc 7.5.0, I run into:
...
In file included from ../bfd/bfd.h:46:0,
                  from gdb/defs.h:37,
                  from gdb/debuginfod-support.c:19:
gdb/debuginfod-support.c: In function ‘bool debuginfod_is_enabled()’:
gdb/../include/diagnostics.h:42:3: error: unknown option after \
   ‘#pragma GCC diagnostic’ kind [-Werror=pragmas]
    _Pragma (DIAGNOSTIC_STRINGIFY (GCC diagnostic ignored option))
    ^
gdb/../include/diagnostics.h:80:3: note: in expansion of macro \
   ‘DIAGNOSTIC_IGNORE’
    DIAGNOSTIC_IGNORE ("-Wstringop-overread")
    ^~~~~~~~~~~~~~~~~
gdb/debuginfod-support.c:201:4: note: in expansion of macro \
   ‘DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD’
     DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD
     ^
...

The problem is that the warning -Wstringop-overread has been introduced for
gcc 11, and we can only tell gcc to ignore if it knows about it.

Fix this by guarding the DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD definition in
diagnostics.c with '#if __GNUC__ >= 11'.

Tested on x86_64-linux, by completing a build.

Committed to trunk.

Thanks,
- Tom

[gdb/build] Fix build for gcc < 11

---
  include/diagnostics.h | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/include/diagnostics.h b/include/diagnostics.h
index 8bf5a3c3d9b..3da88282261 100644
--- a/include/diagnostics.h
+++ b/include/diagnostics.h
@@ -76,8 +76,10 @@
  # define DIAGNOSTIC_IGNORE_STRINGOP_TRUNCATION \
    DIAGNOSTIC_IGNORE ("-Wstringop-truncation")
  +# if __GNUC__ >= 11
  # define DIAGNOSTIC_IGNORE_STRINGOP_OVERREAD \
    DIAGNOSTIC_IGNORE ("-Wstringop-overread")
+#endif
   # define DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL \
    DIAGNOSTIC_IGNORE ("-Wformat-nonliteral")