On Sun, 22 May 2022 08:35:54 GMT, Yasumasa Suenaga <[email protected]> wrote:
>> `Array<T>::_data` is a pseudo flexible array member. "Pseudo" because C++
>> doesn't have flexible array members. The compiler is completely justified in
>> complaining about the apparently out-of-bounds accesses.
>>
>> There is a "well-known" (though moderately ugly) approach to doing flexible
>> array members in C++. Something like this:
>>
>>
>> T* data() {
>> return reinterpret_cast<T*>(
>> reinterpret_cast<char*>(this) + data_offset());
>> }
>>
>>
>> where `data_offset()` is new and private:
>>
>>
>> static size_t data_offset() {
>> return offset_of(Array, _data);
>> }
>>
>>
>> Use `data()` everywhere instead of using `_data` directly.
>>
>> There are other places in HotSpot that use this kind of approach.
>
> Thanks @kimbarrett for your advice! Warnings from array.hpp have gone with
> your suggestion.
Good. I see you found and used the existing `base_offset_in_bytes` (which I'd
overlooked), rather than using my suggested `data_offset`.
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PR: https://git.openjdk.java.net/jdk/pull/8646
