Restore event descriptions immortality

[shipilev]

Upstream code has event descriptions as immortal strings for a reason: they are passed inside the logging classes, and so the references to them may outlive the scope of the current method. We have seen logs corruption because of that before, e.g. in hs_err-s Events section. This PR restores the immortality of event descriptions, producing const strings with macros.

This also stops emitting "(GLOBAL)" for global collections, which I think is what non-generational Shenandoah mode prints. Please tell me if we still need to print "(GLOBAL)" in generational mode.

Tangentially, this also improves performance for compilers that choose to initialize the automatic storage for char msg[1024], see https://isocpp.org/files/papers/P2723R0.html.

Additional testing:

• Eyeballing the GC logs

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Progress

• Change must not contain extraneous whitespace
• Change must be properly reviewed (1 review required, with at least 1 Committer)

Reviewers

• Kelvin Nilsen (@kdnilsen - Committer) ⚠️ Review applies to a550586e
• Y. Srinivas Ramakrishna (@ysramakrishna - Author)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/shenandoah.git pull/253/head:pull/253
$ git checkout pull/253

Update a local copy of the PR:
$ git checkout pull/253
$ git pull https://git.openjdk.org/shenandoah.git pull/253/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 253

View PR using the GUI difftool:
$ git pr show -t 253

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/shenandoah/pull/253.diff

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[mlbridge]

Webrevs

• 01: Full - Incremental (1d51c84b)
• 00: Full (a550586e)

[kdnilsen]

We do distinguish GLOBAL from YOUNG and OLD in generational mode. A GLOBAL collection is when we collect both OLD and YOUNG at the same time. These are generally rare. They show up, for example, if someone explicitly invokes System.gc().

[openjdk]

@shipilev 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:

Restore event descriptions immortality

Reviewed-by: kdnilsen, ysr

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[shipilev]

Thank you!

/integrate

[openjdk]

Going to push as commit 9d87724.

[openjdk]

@shipilev Pushed as commit 9d87724.

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