src: implement MemoryRetainer in Environment
This allows us to track the essentially-global objects in Environment in the heap snapshot. Note that this patch only tracks the fields that can be tracked correctly. There are still several types of fields that cannot be tracked:
- v8::Data including v8::Private, v8::ObjectTemplate etc.
- Internal types that do not implement MemoryRetainer yet
- STL containers with MemoryRetainer* inside
- STL containers with numeric types inside that should not have their nodes elided e.g. numeric keys in maps.
The BaseObject
s are now no longer globals. They are tracked
as arguments in CleanupHookCallbacks referenced by the Environment
node. This model is closer to how their lifetime is managed
internally.
To track the per-environment strong persistent properties, this patch
divides them into those that are also v8::Value
and those that
are just v8::Data
. The values can be tracked by the current
memory tracker while the data cannot.
This patch also implements the MemoryRetainer
interface in several
internal classes so that they can be tracked in the heap snapshot.
Comparison against the heap snapshot generated before this patch
The base objects are now tracked like this (instead of being globals on their own)
Refs: https://github.com/nodejs/node/issues/26776
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
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