8335588: Fix -Wzero-as-null-pointer-constant warnings in calls to Node ctor

[kimbarrett]

Please review this change to callers of the Node constructor that were passing
0 as the first argument, which is of type Node*, thereby triggering
-Wzero-as-null-pointer-constant warnings when enabled. Instead of 0, pass
nullptr. This removes over 2K warnings when building with that option.

Testing: mach5 tier1

---

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-8335588: Fix -Wzero-as-null-pointer-constant warnings in calls to Node ctor (Enhancement - P4)

Reviewers

• Tobias Hartmann (@TobiHartmann - Reviewer)
• Christian Hagedorn (@chhagedorn - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/19994/head:pull/19994
$ git checkout pull/19994

Update a local copy of the PR:
$ git checkout pull/19994
$ git pull https://git.openjdk.org/jdk.git pull/19994/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 19994

View PR using the GUI difftool:
$ git pr show -t 19994

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/19994.diff

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[bridgekeeper]

👋 Welcome back kbarrett! 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]

@kimbarrett 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:

8335588: Fix -Wzero-as-null-pointer-constant warnings in calls to Node ctor

Reviewed-by: thartmann, chagedorn

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 10 new commits pushed to the master branch:

• 77a7078: 8335593: Fix -Wzero-as-null-pointer-constant warning in Type_Array ctor
• f3f90dc: 8335592: Fix -Wzero-as-null-pointer-constant warnings in RootNode ctor
• 7bc8f9c: 8335589: Fix -Wzero-as-null-pointer-constant warnings in IdealLoopTree ctor
• 0db9bc5: 8335290: Rename ClassFile::transform to ClassFile::transformClass
• d51141e: 8321274: Rename ZipEntry.extraAttributes to ZipEntry.externalFileAttributes
• fac74b1: 8334229: Optimize InterpreterOopMap layout
• f9b4ea1: 8334220: Optimize Klass layout after JDK-8180450
• f7af450: 8335110: Fix instruction name and API spec inconsistencies in CodeBuilder
• 8a664a4: 8334734: Remove specialized readXxxEntry methods from ClassReader
• 3a2d426: 8334726: Remove accidentally exposed individual methods from Class-File API

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.

[openjdk]

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

• hotspot-compiler

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[mlbridge]

Webrevs

• 00: Full (b297b6a4)

[TobiHartmann]

Looks good to me.

[chhagedorn]

Looks good to me, too.

[kimbarrett]

Thanks for reviews @TobiHartmann and @chhagedorn

[kimbarrett]

/integrate

[openjdk]

Going to push as commit 3efa93b.
Since your change was applied there have been 25 commits pushed to the master branch:

• 587535c: 8334545: runtime/ClassInitErrors/TestStackOverflowDuringInit.java fails after JDK-8294960
• 68ffec9: 8335479: JFR: Missing documentation for -XX:StartFlightRecording
• 9a91865: 8335395: G1: Verification does not detect references into Free regions
• 13b782c: 8334554: RISC-V: verify & fix perf of string comparison
• 8aaec37: 8322475: Extend printing for System.map
• 19a8a2b: 8335618: Serial: Remove unused definitions in SerialHeap
• cf4f2b5: 8332517: G1: Refactor G1AllocRegion
• 5a8af2b: 8335615: Clean up left-overs from 8317721
• 6923a51: 8335607: Serial: Remove unused collection_attempt_is_safe
• 5866b16: 8335411: RISC-V: Optimize encode_heap_oop when oop is not null
• ... and 15 more: https://git.openjdk.org/jdk/compare/f187c92befbe63e23b11eb0401e5095c44c24389...master

Your commit was automatically rebased without conflicts.

[openjdk]

@kimbarrett Pushed as commit 3efa93b.

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