On Mon, 10 Feb 2025 02:47:58 GMT, Chris Plummer <[email protected]> wrote:
>> Vladimir Kozlov has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> Fix Zero and Minimal VM builds
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/code/CodeCache.java line
> 38:
>
>> 36: public class CodeCache {
>> 37: private static GrowableArray<CodeHeap> heapArray;
>> 38: private static VirtualConstructor virtualConstructor;
>
> What is the reason for switching from the virtualConstructor/hashMap approach
> to using getClassFor()? The hashmap is the model for JavaThread, MetaData,
> and CollectedHeap subtypes.
I think I found the answer. Since there is no longer a vtable,
TypeDataBase.addressTypeIsEqualToType() will no longer work for Codeblobs. I
was wondering if the lack of a vtable might have some negative impact. Glad to
see you found a solution. I hope the lack of a vtable does not creep in
elsewhere. I know it will have some negative impact on things like the "findpc"
functionality, which will no longer be able to tell the user that an address
points to a Codeblob instance. There's no test for this, but users might run
across it.
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PR Review Comment: https://git.openjdk.org/jdk/pull/23533#discussion_r1948352958
