RFR: 8349088: De-virtualize Codeblob and nmethod [v8]

Dean Long dlong at openjdk.org
Fri Feb 14 00:11:16 UTC 2025


On Thu, 13 Feb 2025 17:14:59 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Remove virtual methods from CodeBlob and nmethod to simplify saving/restoring in Leyden AOT cache. It avoids the need to patch hidden VPTR pointer to class's virtual table.
>> 
>> Added C++ static asserts to make sure no virtual methods are added in a future.
>> 
>> Fixed/cleaned SA code which process CodeBlob and its subclasses. Use `CodeBlob::_kind` field value to determine the type of blob.
>> 
>> Tested tier1-5, hs-tier6-rt (for JFR testing), stress, xcomp
>
> Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   rename SA argument

src/hotspot/share/code/codeBlob.hpp line 669:

> 667: 
> 668:   jobject  receiver()          { return _receiver; }
> 669:   ByteSize frame_data_offset() { return _frame_data_offset; }

`frame_data_offset()` seems to be unused.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23533#discussion_r1955373697


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