8292318: Memory corruption in remove_dumptime_info

[iklam]

In JDK-8290833 (#9759), I added a table (SystemDictionaryShared::_saved_cpcache_entries_table) that remembers the initial state of a ConstantPoolCache during CDS dumping. This table is indexed with a ConstantPoolCache*

However, ConstantPoolCache has a complex lifecycle, especially with class redefinition. This makes it difficult to clean up the table. The crash reported in the current bug happened during clean up, probably because an InstanceKlass was still valid but its ConstantPool or ConstantPoolCache were not.

For simplification, I am now storing the information inside the ConstantPoolCache. To compensate for the extra space used, I moved two 32-bit integers next to each other, so the net change in size is zero.

instanceKlass.cpp was reverted to the state before #9759.

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Issue

• JDK-8292318: Memory corruption in remove_dumptime_info

Reviewers

• Coleen Phillimore (@coleenp - Reviewer) ⚠️ Review applies to a2872fae
• Calvin Cheung (@calvinccheung - Reviewer) ⚠️ Review applies to d69ab667

Reviewing

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[mlbridge]

Webrevs

• 03: Full - Incremental (786fb685)
• 02: Full - Incremental (d69ab667)
• 01: Full - Incremental (a2872fae)
• 00: Full (7d38f55f)

[coleenp]

This looks good. This makes sense to me with the comments.

[openjdk]

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

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8292318: Memory corruption in remove_dumptime_info

Reviewed-by: coleenp, ccheung

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[calvinccheung]

I've one question. Looks good otherwise.

[calvinccheung]

Should the above be inside the following condition like before?

if (Arguments::is_dumping_archive()) {

[iklam]

I added a more strict check -- since _initial_entries is set only during CDS dump time, I added an assert that if _initial_entries is non NULL, we must be dumping.

[calvinccheung]

The non NULL check is good.

[iklam]

Thanks for the review @calvinccheung @coleenp
/integrate

[openjdk]

Going to push as commit 27b0f77.

[openjdk]

@iklam Pushed as commit 27b0f77.

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