RFR: 8336080: Fix -Wzero-as-null-pointer-constant warnings in ClassLoaderStats ctor

[David Holmes]

On Thu, 11 Jul 2024 12:31:21 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> src/hotspot/share/classfile/classLoaderStats.hpp line 87:
>> 
>>> 85:     _cld(nullptr),
>>> 86:     _class_loader(),
>>> 87:     _parent(),
>> 
>> Why are these not initialized with `nullptr` given we have code like:
>> 
>> (cls._class_loader == nullptr ? ...)
>> 
>> ?
>
> It would work to do so, though I kind of wish otherwise.
> 
> I wish one wrote
> 
> (cls._class_loader == oop() ? ...)
> 
> and
> 
> _class_loader = oop();
> 
> instead of
> 
> _class_loader = nullptr;
> 
> but I think that ship sailed a long time ago.  Instead we have some really questionable conversions
> available in the (debug-only) oop class.  Maybe we can trim those down a bit now that we consistently
> use nullptr and can use std::nullptr_t as an overload type.  Maybe I'll take a look at that sometime.

Sorry missed this update. Thanks for explanation. I'm okay with things as they stand here.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20109#discussion_r1678796641