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

[Dean Long]

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/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/c1/Runtime1.java line 65:

> 63:   public CodeBlob blobFor(int id) {
> 64:     Address blobAddr = blobsField.getStaticFieldAddress().getAddressAt(id * VM.getVM().getAddressSize());
> 65:     return VM.getVM().getCodeCache().createCodeBlobWrapper(blobAddr);

We don't need to change all the callers if we keep a 1-arg version of createCodeBlobWrapper():

public CodeBlob createCodeBlobWrapper(Address codeBlobAddr) {
    return createCodeBlobWrapper(codeBlobAddr, codeBlobAddr);
}

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PR Review Comment: https://git.openjdk.org/jdk/pull/23533#discussion_r1955316582