Re: [PATCH 0/2 OBV] Fix build with GCC 8

[Martin Sebor <msebor at gmail dot com>]

On 11/22/2017 05:21 AM, Yao Qi wrote:
> Failed to build GDB and GDBserver with recent GCC trunk, due to some
> warnings.  These patches fix the warnings.  Martin had his GDB patch
> to fix the build failure, but don't post it here, so I am going to
> commit my patches to unbreak the build, because I am GCC trunk to build
> GDB mainline everyday.

The implementation of the warning was a work in progress until
yesterday, but the most recent changes should have no impact on
the GDB patch.

The changes do improve GCC's support for detecting unsafe uses
of string functions with non-string arguments (char arrays that
aren't guaranteed to be nul-terminated).  If GDB deals with
character arrays like that it might benefit from making use
of the new attribute nonstring that, besides suppressing
warnings when creating non-nul terminated copies of strings,
also helps detect such unsafe uses.  For example:

  char a[4] __attribute__ ((nonstring));

  strncpy (a, "1234", 4);

  strlen (a);   // unsafe, gets a warning

The attribute has helped uncover a couple of potential bugs
in Glibc.

Martin

> Patches are tested on x86_64-linux.
>
> *** BLURB HERE ***
>
> Yao Qi (2):
>   Fix build with GCC 8: strncpy -> memcpy
>   Fix build with GCC 8: strncpy ->strcpy
>
>  gdb/ChangeLog                | 9 +++++++++
>  gdb/cli/cli-decode.c         | 4 ++--
>  gdb/cp-namespace.c           | 2 +-
>  gdb/gdbserver/ChangeLog      | 4 ++++
>  gdb/gdbserver/remote-utils.c | 2 +-
>  gdb/python/py-gdb-readline.c | 2 +-
>  6 files changed, 18 insertions(+), 5 deletions(-)