8308097: Generational ZGC: Update constructor syntax

[stefank]

ZGC's current constructor syntax works well with some editors, but not all. There is a wish to move over from the current syntax:

ZClass:ZClass() :
    ZSuper(),
    _member0,
    _member1 {
  // Code
  doit();
}

to the following syntax:

ZClass:ZClass()
  : ZSuper(),
    _member0,
    _member1 {
  // Code
  doit();
}

I propose that make this change.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8308097: Generational ZGC: Update constructor syntax

Reviewers

• Erik Österlund (@fisk - Reviewer)
• Axel Boldt-Christmas (@xmas92 - Committer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/13987/head:pull/13987
$ git checkout pull/13987

Update a local copy of the PR:
$ git checkout pull/13987
$ git pull https://git.openjdk.org/jdk.git pull/13987/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 13987

View PR using the GUI difftool:
$ git pr show -t 13987

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/13987.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back stefank! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@stefank The following label will be automatically applied to this pull request:

• hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 00: Full (26218459)

[fisk]

Looks great!

[openjdk]

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8308097: Generational ZGC: Update constructor syntax

Reviewed-by: eosterlund, aboldtch

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 7 new commits pushed to the master branch:

• 01892f9: 8304913: Use OperatingSystem, Architecture, and Version in jlink
• 0f7b1c5: 8299340: CreateProcessW lpCommandLine must be mutable
• 57e7a3f: 8307959: Remove explicit type casts from SerializeClosure::do_xxx() calls
• 97b2ca3: 8307997: gtest:ZIndexDistributorTest fails on PPC64
• ffab1ea: 8308086: GHA: x86_32 host configuration failing with unmet dependencies
• ad348a8: 8303512: Race condition when computing is_loaded property of TypePtr::InterfaceSet
• 911cc7c: 8305819: LogConfigurationTest intermittently fails on AArch64

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[stefank]

/label add hotspot-gc
/label remove hotspot

[openjdk]

@stefank
The hotspot-gc label was successfully added.

[openjdk]

@stefank
The hotspot label was successfully removed.

[xmas92]

lgtm.

[dholmes-ora]

Is this something that should be in the style guide? Presumably we have constructors all through the hotspot code that may not conform to this style.

[stefank]

Is this something that should be in the style guide? Presumably we have constructors all through the hotspot code that may not conform to this style.

ZGC has a much stricter code style than the rest of HotSpot. Previous attempts to drive style guide questions have been quite disappointing (at least to me), so we've carved out our own corner in HotSpot where we try to keep the code uniform.

[stefank]

Thanks for the reviews!
/integrate

[openjdk]

Going to push as commit 60ab135.
Since your change was applied there have been 27 commits pushed to the master branch:

• 599fa77: 8308092: Replace NULL with nullptr in gc/x
• 682359c: 8299075: TestStringDeduplicationInterned.java fails because extra deduplication
• 9d5bab1: 8300081: Replace NULL with nullptr in share/asm/
• 41ee125: 8278411: Implement UseHeavyMonitors consistently, s390 port
• 316bc79: 8308188: ProblemList java/util/concurrent/locks/Lock/OOMEInAQS.java with ZGC on all platforms
• 8686a36: 8307315: Missing ResourceMark in CDS and JVMTI code
• 23cbb2d: 8306860: Avoid unnecessary allocation in List.map() when list is empty
• be54b54: 8307369: Add execution of all svc tests in CI
• 19c8c30: 8305634: Renaming predicates, simple cleanups, and adding summary about current predicates
• 72294c5: 8308024: HttpClient (HTTP/1.1) sends an extraneous empty chunk if the BodyPublisher supplies an empty buffer
• ... and 17 more: https://git.openjdk.org/jdk/compare/8d49ba9e8d3095f850b3007b56488a0c0cf8ddff...master

Your commit was automatically rebased without conflicts.

[openjdk]

@stefank Pushed as commit 60ab135.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[kimbarrett]

Is this something that should be in the style guide? Presumably we have constructors all through the hotspot code that may not conform to this style.

ZGC has a much stricter code style than the rest of HotSpot. Previous attempts to drive style guide questions have been quite disappointing (at least to me), so we've carved out our own corner in HotSpot where we try to keep the code uniform.

As @stefank said, ZGC has a stricter style, making choices in some areas where
there doesn't seem to be universal (or even widespread) agreement and usage.
Constructor style is one of those areas - we're all over the place here, with
some styles seeming quite bad to some people. That said, while I personally
didn't care for the prior ZGC constructor style (it requires non-default emacs
configuration), this new one is what I would prefer if we were going to mandate
something.