RFR: 8372617: Save and restore stubgen stubs when using an AOT code cache [v8]

[Vladimir Kozlov]

On Thu, 29 Jan 2026 10:48:32 GMT, Andrew Dinn <adinn at openjdk.org> wrote:

>> This PR adds save and restore of all generated stubs to the AOT code cache on x86 and aarch64. Other arches are modified to deal with the related generic PAI changes.
>> 
>> Small changes were required to the aarch64 and x86_64 generator code in order to meet two key constraints:
>> 1. the first declared entry of every stub starts at the first instruction in the stub code range
>> 2. all data/code cross-references from one stub to another target a declared stub entry
>
> Andrew Dinn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Run AOTCodeFlags test with multiple GCs

You also need to add CPU features check to aotCodeCache from `premain`
Some tests asserted because they use `UseSSE` flag to low features: `compiler/arguments/TestUseSSE42IntrinsicsWithLowLevelSSE.java`

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PR Comment: https://git.openjdk.org/jdk/pull/28433#issuecomment-3820805075