Re: [PATCH v2 10/10] Add --enable-ubsan

[Eli Zaretskii <eliz at gnu dot org>]

> From: Tom Tromey <tom@tromey.com>
> Cc: Tom Tromey <tom@tromey.com>
> Date: Mon,  1 Oct 2018 22:44:20 -0600
> 
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -103,6 +103,14 @@ CSKY GNU/LINUX			csky*-*-linux
>    ** The gdb.Progspace type has a new 'objfiles' method, which returns the list
>       of objfiles associated to that program space.
>  
> +* Configure changes
> +
> +--enable-ubsan
> +
> +  Enable or disable the undefined behavior sanitizer.  Release
> +  versions of gdb disable this by default, but development versions

"GDB", capitalized, I guess?

> --- a/gdb/README
> +++ b/gdb/README
> @@ -538,6 +538,13 @@ more obscure GDB `configure' options are not listed here.
>       the compiler, which will fail the compilation if the compiler
>       outputs any warning messages.
>  
> +`--enable-ubsan'
> +     Enable the GCC undefined behavior sanitizer.  By default this is
> +     disabled in GDB releases, but enabled when building from git.
> +     The undefined behavior sanitizer checks for C++ undefined
> +     behavior.  It has a performance cost, so if you are looking at
> +     GDB's performance, you should disable it.

Does this require some minimal version of g++?  If so, I think we
should mention that.  And what about testing for this support at
configure time?

> +
> +# ac_fn_cxx_try_link LINENO
> +# -------------------------
> +# Try to link conftest.$ac_ext, and return whether this succeeded.
> +ac_fn_cxx_try_link ()
> +{
> +  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
> +  rm -f conftest.$ac_objext conftest$ac_exeext
> +  if { { ac_try="$ac_link"
> +case "(($ac_try" in
> +  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
> +  *) ac_try_echo=$ac_try;;
> +esac
> +eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
> +$as_echo "$ac_try_echo"; } >&5
> +  (eval "$ac_link") 2>conftest.err
> +  ac_status=$?
> +  if test -s conftest.err; then
> +    grep -v '^ *+' conftest.err >conftest.er1
> +    cat conftest.er1 >&5
> +    mv -f conftest.er1 conftest.err
> +  fi
> +  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> +  test $ac_status = 0; } && {
> +	 test -z "$ac_cxx_werror_flag" ||
> +	 test ! -s conftest.err
> +       } && test -s conftest$ac_exeext && {
> +	 test "$cross_compiling" = yes ||
> +	 test -x conftest$ac_exeext
> +       }; then :
> +  ac_retval=0
> +else
> +  $as_echo "$as_me: failed program was:" >&5
> +sed 's/^/| /' conftest.$ac_ext >&5
> +
> +	ac_retval=1
> +fi
> +  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
> +  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
> +  # interfere with the next link command; also delete a directory that is
> +  # left behind by Apple's compiler.  We do this before executing the actions.
> +  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
> +  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
> +  as_fn_set_status $ac_retval
> +
> +} # ac_fn_cxx_try_link
>  cat >config.log <<_ACEOF
>  This file contains any messages produced by compilers while
>  running configure, to aid debugging if configure makes a mistake.

Is this hunk related to the issue at hand?

The documentation parts are approved, with the above nits fixed.

Thanks.