On Thu, 10 Feb 2022 11:57:25 GMT, Alex Menkov <[email protected]> wrote:
>> src/hotspot/share/services/heapDumper.cpp line 2293:
>>
>>> 2291: // Writes HPROF_GC_CLASS_DUMP records
>>> 2292: // For array classes we need signers and protection domain from
>>> their bottom classes
>>> 2293: // so do_class_dump skips array classes and dumps array classes
>>> with corresponding instance class.
>>
>> I'm having trouble parsing this comment. Can you clarify?
>
> HPROF_GC_CLASS_DUMP records contain references to signers and protection
> domain objects.
> But this is properties of InstanceKlass, for array classes the properties
> from their element classes are written (or NULL for arrays of primitive
> types).
> do_class_dump callback skips array classes:
> if (k->is_instance_klass()) {
> DumperSupport::dump_class_and_array_classes(writer(), k);
> }
>
> dump_class_and_array_classes dumps the class and then iterate over array
> classes (k->array_klass_or_null()) and writes records for them (using signer
> and protection domain from the instance class specified).
>
> This approach also skips primitive type arrays (they don't have corresponding
> InstanceKlass) - they are dumped separately.
>
> I added the comment to explain why do_class_dump goes this tricky way.
> Do you have any suggestions how to rephrase it to make clearer?
Sorry about the delay. I didn't see your response when it came in.
It seems like this comment belongs with do_class_dump(). Putting it here is
kind of confusing. Also, what is meant by "bottom class"? Do you mean the
element type of the array?
-------------
PR: https://git.openjdk.java.net/jdk/pull/7384
