8367253: RISC-V: refactor dependent cpu extensions

[Hamlin-Li]

Hi,
Can you help to review this patch?

Dependent extensions could be improved in several ways.

Currently, the dependent cpu extensions are processed in 2 separate places:

1. update_flag() when calling VM_Version::setup_cpu_available_features()
2. at the end of VM_Version::common_initialize().

And, dependency relationship can only be expressed in (1:1) way, can not be expressed (1:N) way, but in fact some extensions can depend on several different other extensions, for example, zvfh depends on zvf and rvv. It's would be better to support this (1:N) relationship.

So, this PR brings several benefits:

1. VM options directly related to CPU extensions are automatically set, and they are all set in one place.
2. keep synchronization between CPU extensions (information in RVFeatureValue) and and VM options. Previously, code in common_initialize wont' sync to RVFeatureValue, unless do it manually, which is error-prone.
3. support to express (1:N) dependency relationship among cpu extensions and related vm options.

Thanks!

Test

$TEST_JDK/bin/java -XX:+UnlockExperimentalVMOptions -XX:-UseRVV -XX:+PrintFlagsFinal -version | grep -e UseRVV -e UseZvbc -e UseZvfh -e UseZvkn
OpenJDK 64-Bit Server VM warning: Cannot enable UseZvbb on cpu without any of the supports: v (disabled)
OpenJDK 64-Bit Server VM warning: Cannot enable UseZvbc on cpu without any of the supports: v (disabled)
OpenJDK 64-Bit Server VM warning: Cannot enable UseZvfh on cpu without any of the supports: v (disabled), Zfh (enabled)
     bool UseRVV                                   = false                             {ARCH diagnostic} {command line}
     bool UseZvbc                                  = false                           {ARCH experimental} {default}
     bool UseZvfh                                  = false                             {ARCH diagnostic} {default}
     bool UseZvkn                                  = false                           {ARCH experimental} {default}

$TEST_JDK/bin/java -XX:+UnlockExperimentalVMOptions -XX:-UseZfh -XX:+PrintFlagsFinal -version | grep -e UseRVV -e UseZvbc -e UseZvfh -e UseZvkn
OpenJDK 64-Bit Server VM warning: Cannot enable UseZvfh on cpu without any of the supports: v (enabled), Zfh (disabled)
     bool UseRVV                                   = true                              {ARCH diagnostic} {default}
     bool UseZvbc                                  = true                            {ARCH experimental} {default}
     bool UseZvfh                                  = false                             {ARCH diagnostic} {default}
     bool UseZvkn                                  = false                           {ARCH experimental} {default}

---

Progress

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Issue

• JDK-8367253: RISC-V: refactor dependent cpu extensions (Enhancement - P4)

Reviewers

• Ludovic Henry (@luhenry - Committer) Review applies to 0dd9f9c3
• Fei Yang (@RealFYang - Reviewer)

Reviewing

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@Hamlin-Li This change now passes all automated pre-integration checks.

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8367253: RISC-V: refactor dependent cpu extensions

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At the time when this comment was updated there had been 42 new commits pushed to the master branch:

• fdbba04: 8368775: Remove outdated comment in OutlineTextRenderer
• 6165921: 7156751: [macosx] Problem with printing
• 08b677b: 8071277: G1: Merge commits and uncommits of contiguous memory
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⚠️ @Hamlin-Li This pull request contains merges that bring in commits not present in the target repository. Since this is not a "merge style" pull request, these changes will be squashed when this pull request in integrated. If this is your intention, then please ignore this message. If you want to preserve the commit structure, you must change the title of this pull request to Merge <project>:<branch> where <project> is the name of another project in the OpenJDK organization (for example Merge jdk:master).

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@Hamlin-Li this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

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[RealFYang]

Hi, Thanks for the refactoring work. I have a small question.

[RealFYang]

Latest version LGTM.

[Hamlin-Li]

Latest version LGTM.

Thank you!

[Hamlin-Li]

/integrate

[openjdk]

Going to push as commit 9d71af1.
Since your change was applied there have been 44 commits pushed to the master branch:

• 63688d8: 8368822: Refactor Float16.valueOf(double)
• 9d9c0e0: 8368793: java/lang/StringBuilder/RacingSBThreads.java timed out in Xcomp subtest
• fdbba04: 8368775: Remove outdated comment in OutlineTextRenderer
• ... and 41 more: https://git.openjdk.org/jdk/compare/d1ea6ea22d49884bec53f89fad7029400fb1d7f2...master

Your commit was automatically rebased without conflicts.

[openjdk]

@Hamlin-Li Pushed as commit 9d71af1.

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