RFR: 8353597: Refactor handling VM options for AOT cache input and output [v3]

[Dan Heidinga]

On Thu, 3 Apr 2025 20:31:50 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Since [JEP 483: Ahead-of-Time Class Loading & Linking](https://openjdk.org/jeps/483), VM options such as `-XX:AOTCache `are implemented as aliases of "classical" CDS options such as `-XX:SharedArchiveFile`.
>> 
>> In anticipation of the [JEP: Ahead-of-time Command Line Ergonomics](https://bugs.openjdk.org/browse/JDK-8350022), we should refactor the code that deals with the AOT options. Specifically, as we expect the JVM to be able to load from an "input AOT cache" and write to an "output AOT cache", we should clearly identify the input and output caches in separate APIs:
>> 
>> 
>> const char* CDSConfig::input_static_archive_path();
>> const char* CDSConfig::input_dynamic_archive_path();
>> const char* CDSConfig::output_archive_path();
>> 
>> 
>> This PR also cleans up the code by:
>> - renaming a few function to reflect what they actually do
>> - moving more "config" management code into cdsConfig.cpp
>> 
>> There's also a behavioral bug fix: before this PR, `-XX:AOTCache` was handled by the `ergo_init_classic_archive_paths()` function, which allows two files to be specified. E.g., `java -XX:AOTCache=static.jsa:dynamic.jsa`. That's because `-XX:AOTCache` was implemented as an alias of `-XX:SharedArchiveFile`, and the latter allows this usage.
>> 
>> However, this behavior is not specified in JEP 483. Allowing two files in -XX:AOTCache will cause unnecessary complexity when we implement [JDK-8353598: Allow AOT cache to be used in training run](https://bugs.openjdk.org/browse/JDK-8353598). Therefore, I added new test cases to disallow the use of two files.  This also means that we don't need to modify  the already over-complicated `ergo_init_classic_archive_paths()` for the AOT use cases
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   @lmesnik comments

src/hotspot/share/cds/cdsConfig.cpp line 598:

> 596:     // - SharedArchiveFile is not specified and the VM doesn't have a compatible default archive
> 597: 
> 598: #define __THEMSG " is unsupported when base CDS archive is not loaded. Run with -Xlog:cds for more info."

Do we want to start transitioning existing `-Xlog:cds` options to be `:aot` options?  I think making the switch would match out long term direction

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PR Review Comment: https://git.openjdk.org/jdk/pull/24401#discussion_r2031644463