RFR: 8296496: Overzealous check in sizecalc.h prevents large memory allocation

[Aleksei Ivanov]

Hi Patrick,

It is the reason why it should be updated. The checks in 
IS_SAFE_STRUCT_SIZE are performed with the cast: (size_t)(a). If the 
cast is omitted here, it may yield a different result.

What if ‘a’ is a signed integer with negative value?

Regards,
Alexey

On 08/11/2022 15:25, Patrick Chen wrote:
> But you forgot that   (IS_SAFE_STRUCT_SIZE((a), (m), (n)) ? 
> ((func)((a) + (size_t)(m) * (size_t)(n))) : FAILURE_RESULT) is not the 
> same equivalence to   (IS_SAFE_STRUCT_SIZE((a), (m), (n)) ? 
> ((func)((size_t)(a) + (size_t)(m) * (size_t)(n))) : FAILURE_RESULT)
> because of the ((func)((size_t)(a) + (size_t)(m) * (size_t)(n))
>
> Le mar. 8 nov. 2022 à 14:59, Alexey Ivanov <aivanov at openjdk.org> a écrit :
>
>     On Mon, 7 Nov 2022 22:04:55 GMT, Alexander Zuev
>     <kizune at openjdk.org> wrote:
>
>     <SNIP>
>
>     To be safe, `a` should also be cast.
>
>     And `IS_SAFE_STRUCT_SIZE` should also be updated to pass
>     `(size_t)(m) * (size_t)(n)` to `IS_SAFE_SIZE_ADD` instead of `(m)
>     * (n)`.
>
>     -------------
>
>     PR: https://git.openjdk.org/jdk/pull/11030
>