RFR: 8255495: Support CDS Archived Heap for uncompressed oops

[Mikhailo Seledtsov]

On Wed, 26 Jan 2022 02:48:05 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:

> This proposed change adds support for uncompressed oops for CDS archived heap. It is needed
> for supporting archived heap for ZGC in the future. For now, only G1GC is supported with this change.
> During dump time with compressed oops disabled, the MaxHeapSize is set to 4GB. This is to ensure
> the offset of any object in the heap from the bottom of the heap is always a 32-bit integer.
> 
> Passed CI tiers 1 - 4 and hs-tier7-rt tests.
> 
> Preliminary HelloWorld startup perf. improvement:
> 
> instr delta =    -68813432    -49.7140%
> time  delta =      -14.720 ms -20.3599%

Test and test group changes look good to me.

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PR: https://git.openjdk.java.net/jdk/pull/7223