Indu Bhagat <indu.bha...@oracle.com> writes:
> [...]
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index ffde9df85fd3..de651183a703 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -17079,6 +17079,14 @@ and @option{-fsanitize=kernel-hwaddress}.
> To disable instrumentation of builtin functions use
> @option{--param hwasan-instrument-mem-intrinsics=0}.
>
> +@item memtag-instrument-stack
> +Enable MTE tagging of statically sized stack-allocated variables. This kind
> of
> +code generation is enabled by default when using @option{-fsanitize=memtag}.
> +
> +@item memtag-instrument-allocas
> +Enable MTE tagging of dynamically sized stack-allocated variables. This
> kind of
> +code generation is enabled by default when using @option{-fsanitize=memtag}.
> +
Since this is a target-independent parameter, it might be better
to use something more neutral than "MTE", such as "hardware memory
tagging". Same elsewhere.
> [...]
> diff --git a/gcc/opts.cc b/gcc/opts.cc
> index 86c6691ecec4..00db662c32ef 100644
> --- a/gcc/opts.cc
> +++ b/gcc/opts.cc
> [...]
> @@ -2780,6 +2788,13 @@ common_handle_option (struct gcc_options *opts,
> SET_OPTION_IF_UNSET (opts, opts_set,
> param_hwasan_instrument_allocas, 0);
> }
> + /* Memtag sanitizer implies HWASAN but with tags always generated by
> the
> + hardware randomly. */
> + if (opts->x_flag_sanitize & SANITIZE_MEMTAG)
> + {
> + SET_OPTION_IF_UNSET (opts, opts_set,
> + param_hwasan_random_frame_tag, 1);
> + }
Does this have any effect in practice? The default seems to be 1,
so I would expect this to be a nop. The pattern elsewhere in the
sanitiser code seems to be to use SET_OPTION_IF_UNSET only to turn
features off.
Thanks,
Richard
