8302777: CDS should not relocate heap if mapping fails

[iklam]

Please review this trivial fix: if the CDS archive heap is not available due to CRC errors, we shouldn't try to relocate its contents.

The bug was introduced in JDK-8296158. Previously, if the CRC check fails, FileMapRegion::mapped_base() will be NULL for the heap regions, and thus we will skip the relocation in ArchiveHeapLoader::patch_native_pointers().

However, since JDK-8296158, FileMapRegion::mapped_base() might be non-zero after CRC check has failed.

A proper fix is in JDK-8302790 -- we should clear FileMapRegion::mapped_base() when mapping fails.

However, that's a more involved fix and requires more testing.

In the meantime, this PR will fix this crash. Also, it's a good idea to make sure the archive heap is available before doing anything with it.

---

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Issue

• JDK-8302777: CDS should not relocate heap if mapping fails

Reviewers

• Calvin Cheung (@calvinccheung - Reviewer)

Reviewing

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[mlbridge]

Webrevs

• 00: Full (40fe64bf)

[calvinccheung]

Fix looks safe and trivial.

[iklam]

Thanks @calvinccheung for the review.
The new code passes tier-4, where the crash was found.
/integrate

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

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8302777: CDS should not relocate heap if mapping fails

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[iklam]

/integrate

[openjdk]

Going to push as commit a263f28.

[openjdk]

@iklam Pushed as commit a263f28.

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