RFR: 8374445: Fix -Wzero-as-null-pointer-constant warnings in JfrSet [v2]

[Markus Grönlund]

On Thu, 15 Jan 2026 16:15:52 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> src/hotspot/share/jfr/utilities/jfrSet.hpp line 72:
>> 
>>> 70:     }
>>> 71:     for (unsigned i = 0; i < table_size; ++i) {
>>> 72:       ::new (&table[i]) K{};
>> 
>> Is this the new (placement pun intended) way to do a placement new, using the outer scope operator ::? Or is it because we don't know what Hotspot type this is?
>
> It's the same old way one should always do it.  If one wants global placement
> new, one should say so.  An unqualified `new` expression does a class-based
> lookup of `operator new`, so if the class has one (and lots of ours do), that
> will be used.  We don't want that here, regardless of the type of `K`.  As it
> happens, for all current uses `K` is a fundamental type, so it doesn't matter.
> But it's clearer and future proof to be explicit.

And the new location for global new is cppstdlib/new.hpp - ok.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29022#discussion_r2695233003