RFR: 8306582: Remove MetaspaceShared::exit_after_static_dump() [v2]

[Alan Bateman]

On Tue, 25 Jul 2023 18:48:58 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>> Currently we exit the VM after static dumping with `MetaspaceShared::exit_after_static_dump()`. 
>> 
>> 
>>  // We have finished dumping the static archive. At this point, there may be pending VM
>>  // operations. We have changed some global states (such as vmClasses::_klasses) that
>>  // may cause these VM operations to fail. For safety, forget these operations and
>>  // exit the VM directly.
>>  void MetaspaceShared::exit_after_static_dump() {
>>    os::_exit(0);
>>  } 
>> 
>> 
>> As the comment suggests, the VM state is altered when preparing and performing the static dump, so this change aims to prevent these state changes so the VM can exit normally after the static dump completes. There are three major aspects to this change:
>> 1. Since the resolved references array in the Constant Pool is altered when preparing for a static dump, a "scratch copy" is created and archived instead 
>> 2. Symbols are sorted by address and have their hash recalculated. Similarly to point 1, the copies of the symbols that are to be archived have their hashes updated as opposed to the originals.
>> 3. The handling of -Xshare:dump during argument parsing such that the VM can continue and exit normally with an exit code of 0.
>> 
>> Verified with tier 1-9 tests.
>
> Matias Saavedra Silva 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 five additional commits since the last revision:
> 
>  - Merge fix
>  - Restores java loaders
>  - Ioi and David comments
>  - Windows fix
>  - 8306582: Remove MetaspaceShared::exit_after_static_dump()

src/java.base/share/native/libjli/java.c line 464:

> 462:     if (dumpSharedSpaces) {
> 463:       CHECK_EXCEPTION_LEAVE(0);
> 464:       LEAVE();

What is exit status ($?) when -Xshare:dump fails. It looks like any pending exception will be printed and it will exit with 0 but maybe I've missed something.

In passing, the java launcher uses 4-space indent rather than 2.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14879#discussion_r1275366634