[crac] RFR: 8350845: [CRaC] Support C/R engines in form of a library [v2]

[Timofei Pushkin]

On Tue, 4 Mar 2025 13:26:12 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

>> Timofei Pushkin has updated the pull request incrementally with five additional commits since the last revision:
>> 
>>  - Fix platform-specific issues
>>  - Rewrite crexec on C++
>>  - Change engine options help
>>  - Move engine wrapper into its own files
>>  - Address review comments
>
> test/jdk/jdk/crac/CracEngineOptionsTest.java line 90:
> 
>> 88:                     "CRaC engine option: 'keep_running' = 'true'",
>> 89:                     "CRaC engine option: 'args' = '-v -v -v -v'",
>> 90:                     "CRaC engine option: 'keep_running' = 'false'");
> 
> I think that providing the same option twice should result in warning, at least.

Not always, for example an engine can interpret `--XX:CRaCEngineOptions=args=--arg1 --XX:CRaCEngineOptions=args=--arg2` as `--XX:CRaCEngineOptions=args="--arg1 --arg2"` (i.e. concatenate all `args` into a single string), so it is up to the engine implementation to issue a warning.

I can implement such warning in crexec but that would require keeping track of whether each option has been set or not.

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PR Review Comment: https://git.openjdk.org/crac/pull/207#discussion_r1979552419