RFR: 8263377: Store method handle linkers in the 'non-nmethods' heap

[Yi-Fan Tsai]

On Wed, 18 May 2022 13:19:52 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> 8263377: Store method handle linkers in the 'non-nmethods' heap
>
> src/hotspot/share/code/codeBlob.hpp line 468:
> 
>> 466:   MethodHandleIntrinsicBlob(Method* method, int mhi_size, CodeBuffer *code_buffer);
>> 467: 
>> 468:   Method*   _method;
> 
> Sorry, I know that this is still a draft (I was taking a sneak peak), but note that `BufferBlob` subclasses have a fixed header size `sizeof(BufferBlob)` (see the `BufferBlob` constructor in codeBlob.cpp).
> 
> Adding a field here can lead to the the start of the code section being overwritten. Just FYI, in case you were encountering any weird bugs.
> 
> I think the right move, if you want to add a field here, is to extend `RuntimeBlob` directly, and pass the right header size to the super constructor (or pass the right header size from all `BufferBlob` subclasses).

Thanks for catching the bug.

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PR: https://git.openjdk.java.net/jdk/pull/8760