8294902: Undefined Behavior in C2 regalloc with null references

[GoeLin]

I backport this for parity with 17.0.7-oracle.

I had to resolve arena.cpp because there is ASSERT coding in
the context, which already contains the new code.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
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• Commit message must refer to an issue

Issue

• JDK-8294902: Undefined Behavior in C2 regalloc with null references

Reviewers

• Richard Reingruber (@reinrich - Reviewer)
• Paul Hohensee (@phohensee - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk17u-dev pull/1106/head:pull/1106
$ git checkout pull/1106

Update a local copy of the PR:
$ git checkout pull/1106
$ git pull https://git.openjdk.org/jdk17u-dev pull/1106/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 1106

View PR using the GUI difftool:
$ git pr show -t 1106

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk17u-dev/pull/1106.diff

[bridgekeeper]

👋 Welcome back goetz! 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]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (37562f9e)

[reinrich]

Changes look good to me.
Thanks, Richard.

[openjdk]

@GoeLin 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:

8294902: Undefined Behavior in C2 regalloc with null references

Reviewed-by: rrich, phh

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 84 new commits pushed to the master branch:

• 5027f56: 8288332: Tier1 validate-source fails after 8279614
• d0e0633: 8302692: [17u] Update GHA Boot JDK to 17.0.6
• fb6d6fe: 8301842: JFR: increase checkpoint event size for stacktrace and string pool
• cf5490b: 8297437: javadoc cannot link to old docs (with old style anchors)
• 334ec9a: 8282958: Rendering Issues with Borders on Windows High-DPI systems
• d2409a7: 8295777: java/net/httpclient/ConnectExceptionTest.java should not rely on system resolver
• 0ce70e3: 8294958: java/net/httpclient/ConnectTimeout tests are slow
• efe8676: 8279614: The left line of the TitledBorder is not painted on 150 scale factor
• 036029e: 8281170: Test jdk/tools/jpackage/windows/WinInstallerIconTest always fails on Windows 11
• 9e26f38: 8300266: Detect Virtualization on Linux aarch64
• ... and 74 more: https://git.openjdk.org/jdk17u-dev/compare/ba023c6bf32da357e74bcb93b3cf13154b806866...master

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.

[phohensee]

Lgtm.

[GoeLin]

/integrate

[openjdk]

Going to push as commit a0cda28.
Since your change was applied there have been 90 commits pushed to the master branch:

• 3c1e03b: 8251177: [macosx] The text "big" is truncated in JTabbedPane
• bf4e659: 8272702: Resolving URI relative path with no / may lead to incorrect toString
• da62b2b: 8299970: Speed up compiler/arraycopy/TestArrayCopyConjoint.java
• fcd9110: 8298472: AArch64: Detect Ampere-1 and Ampere-1A CPUs and set default options
• a6f4cf1: 8302152: Speed up tests with infinite loops, sleep less
• 49ff97c: 8301342: Prefer ArrayList to LinkedList in LayoutComparator
• 5027f56: 8288332: Tier1 validate-source fails after 8279614
• d0e0633: 8302692: [17u] Update GHA Boot JDK to 17.0.6
• fb6d6fe: 8301842: JFR: increase checkpoint event size for stacktrace and string pool
• cf5490b: 8297437: javadoc cannot link to old docs (with old style anchors)
• ... and 80 more: https://git.openjdk.org/jdk17u-dev/compare/ba023c6bf32da357e74bcb93b3cf13154b806866...master

Your commit was automatically rebased without conflicts.

[openjdk]

@GoeLin Pushed as commit a0cda28.

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