Review Request JDK-8193325: StackFrameInfo::getByteCodeIndex returns wrong value if bci > 32767

[David Holmes]

Hi Mandy,

On 13/12/2017 10:42 AM, mandy chung wrote:
> http://cr.openjdk.java.net/~mchung/jdk10/webrevs/8193325/webrev.00/
> 
> This fixes the bug in hotspot that sets the bci field as int but it's of 
> short type and also StackFrameInfo to return a proper bci value.  Coleen 
> suggests not to change set_bci to take jushort but instead do the cast 
> as in the proposed fix.  The VM is in favor of C++ types and stop 
> propagation of Java types.  bci is of int in VM implementation and so be 
> consistent.

I must admit I'm unclear why the VM needs the BCI to be an int when 
logically it is a jushort, but perhaps, as per getByteCodeIndex() it 
needs to be able to store "-1" to indicate no-bci?

The fix itself seems fine, though if we're going to chop off the VM 
value at 16-bits perhaps we should assert that it isn't a value that 
requires > 16 bits?

Thanks,
David

> 
> Mandy
> [1] mail.openjdk.java.net/pipermail/core-libs-dev/2017-December/050581.html