[jdk17u-dev] RFR: 8276799: Implementation of JEP 422: Linux/RISC-V Port [v3]

[Fei Yang]

> The RISC-V port was originally developed at Huawei Technologies, then integrated into OpenJDK 19.
> 
> The 17u version of the port has continued to be maintained in the openjdk/riscv-port-jdk17u repo later
> and has been tested for several months. There are few changes to shared HotSpot code (mostly the main
> one is C1 conditional move/branch support for RISC-V). As required by 17u maintainer, changes to shared
> code has been kept to a minimum. Only enabling shared changes are incorporated and these changes are
> properly guarded with macro RISCV. So this 17u port should not breaking existing code and, although it is
> a large patch, finally integrating it into 17u upstream should be low risk.
> 
> Testing on linux-riscv64 platform:
> - [x] Bootcycle (release & fastdebug build)
> - [x] Tier1-4 tests (release build)
> - [x] Benchmark workloads (Dacapo, SPECJbb2015, SPECJVM2008, Renaissance. release build)

Fei Yang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:

 - Adds back commit ef86ea2842b1a204834291d9d6665bfcd7b75fbc
 - Merge branch 'master' into jep422-17u-backport
 - Merge branch 'master' into jep422-17u-backport
 - 8305236: Some LoadLoad barriers in the interpreter are unnecessary after JDK-8220051
 - Merge remote-tracking branch 'upstream/master' into jep422-17u-backport
 - Merge remote-tracking branch 'upstream/master' into jep422-17u-backport
 - 8276799: Implementation of JEP 422: Linux/RISC-V Port

-------------

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/1427/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/1427/files/f3822a64..97492d63

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1427&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1427&range=01-02

  Stats: 977 lines in 39 files changed: 528 ins; 193 del; 256 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1427.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1427/head:pull/1427

PR: https://git.openjdk.org/jdk17u-dev/pull/1427