[GR-48949] For instance objects, move the identity hashcode from the object header into the object. #7835
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Hello @christianhaeubl, could you please update the description of the PR to include the justification for the change? Thank you. |
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@christianhaeubl Does this patch require any updates to the debuginfo documentation? |
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@adinn : good point, I adjusted the documentation accordingly. |
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Debug info changes look good.
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…of a synthetic field.
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For instance objects, it makes sense to move the identity hashcode from the object header into the object. If there are any gaps in the object layout, the identity hashcode can be placed in such a gap, which decreases memory usage. If there are no gaps, the identity hashcode is appended to the object, resulting in the same memory usage as before. So, this PR strictly reduces memory usage.
As a side effect, it is more likely that the Native Image field offsets are different from the offsets used by HotSpot. This makes it easier to diagnose and debug when a field offset computed at image build time is wrongly used at image run time.