> On Aug 15, 2022, at 9:28 AM, Nathan Sidwell <nat...@acm.org> wrote:
>
> On 8/2/22 10:44, Qing Zhao wrote:
>> Hi, Nathan,
>> I am adding a new bitfield “decl_not_flexarray” in “tree_decl_common”
>> (gcc/tree-core.h) for the new gcc feature -fstrict-flex-arrays.
>> ====
>> diff --git a/gcc/tree-core.h b/gcc/tree-core.h
>> index ea9f281f1cc..458c6e6ceea 100644
>> --- a/gcc/tree-core.h
>> +++ b/gcc/tree-core.h
>> @@ -1813,7 +1813,10 @@ struct GTY(()) tree_decl_common {
>> TYPE_WARN_IF_NOT_ALIGN. */
>> unsigned int warn_if_not_align : 6;
>> - /* 14 bits unused. */
>> + /* In FIELD_DECL, this is DECL_NOT_FLEXARRAY. */
>> + unsigned int decl_not_flexarray : 1;
>
> Is it possible to invert the meaning here -- set the flag if it /IS/ a
> flexible array? negated flags can be confusing, and I see your patch sets it
> to '!is_flexible_array (...)' anyway?
>
>> +
>> + /* 13 bits unused. */
>> /* UID for points-to sets, stable over copying from inlining. */
>> unsigned int pt_uid;
>> ====
>> (Please refer to the following for details:
>> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598556.html
>> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598965.html
>
>
>
>> )
>> Richard mentioned the following:
>> "I've not seen it so you are probably missing it - the bit has to be
>> streamed in tree-streamer-{in,out}.cc to be usable from LTO. Possibly
>> C++ module streaming also needs to handle it.”
>> I have figured out that where to add the handling of the bit in
>> “tree-streamer-{in, out}.cc,
>> However, it’s quite difficult for me to locate where should I add the
>> handling of this new bit in
>> C++ module streaming, could you please help me on this?
>
>
> add it in to trees_{in,out}::core_bools. You could elide streaming for
> non-FIELD_DECL decls.
Got it. Thanks a lot.
Qing
>
> Hope that helps.
>
> nathan
>
>
>
>> Thanks a lot for your help.
>> Qing
>
>
> --
> Nathan Sidwell
