TrustNonStaticFinalFields clarification

Vitaly Davidovich vitalyd at
Sat Apr 18 01:07:09 UTC 2015

Hi guys,

I'm hoping someone could clarify/confirm my understanding of this
experimental flag's effects:

1) final instance array length is constant propagated? Even if array is
passed in as ctor arg rather than being instantiated in the ctor?
2) final instance fields seen as never null are forever considered as such?
So even if a method call on that object is fully eliminated (e.g. the
method is empty) no null check is left behind?
3) concrete runtime type of the instance field is propagated to uses and no
additional type checks are done? Say the declared type is an
interface/abstract with multiple implementations loaded but only one type
stored in the field - is a type check eliminated and calls are fully
4) primitive type final fields have their value constant propagated if
compiler sees only one value always stored?
5) do derived classes and base class share field profile or not? For
example subclasses always store concrete type but each subclass stores a
different type from the others.

Also, there's been some talk about doing these optimizations automatically
with invalidations builtin.  Just curious where that stands.


sent from my phone
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