RFR: 8301403: Eliminate memory allocations in JVMFlag::printFlags during signal handling [v3]

[Gerard Ziemski]

On Fri, 19 Jul 2024 19:40:23 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> f you are set on your enum idea, that is fine. I just worry that such coding will bite us in the future if we ever want to refactor flag handling. But I don't want to drag this PR out if you want to be done with it.

At this point I think I'd prefer using `CHeapBitMap`, but it sounds like your objection is that it is not `Not thread-safe, nor re-entrant-safe`.

I don't like the idea of using script, as it would make things more complex for IDE based compilations (doable, but extra steps). Is there any way we can use `constexpr` and other compile time c++ features to help here?

But, first I'd like to hear which API you recommend we use for memory allocation using stack.

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PR Comment: https://git.openjdk.org/jdk/pull/20202#issuecomment-2240062136