On 12/12/17 5:29 PM, John Rose wrote:
On Dec 12, 2017, at 5:24 PM, David Holmes <david.hol...@oracle.com
<mailto:david.hol...@oracle.com>> wrote:
as per getByteCodeIndex() it needs to be able to store "-1" to
indicate no-bci?
Yes, that's the essential requirement, to encode a "none" value.
FWIW, one natural way to do that here would be to make the int field
@Stable and have the accessor return one less than the stored field value.
Then, by the rules of @Stable, the field starts out at the logical value
of -1, and can transition to a valid BCI if patched to a non-zero value
in the range 1..(2^16).
Thanks for suggesting @Stable that would help this case. I can't
understand why the field has to be patched with non-zero value. Is this
something special requirement for @Stable?
Making it "final" and initialized to -1 is not too terrible either,
although
that creates some tech. debt we need to discharge when upgrading
finals to be trustable.
Mandy
[1]
http://cr.openjdk.java.net/~bchristi/8185925/StackFrameInfo.jol.rmDeclClass.txt
