On 11/30/18 7:46 PM, JC Beyler wrote:
Questions because I'm not familiar with JVMCI consequences so not
really comments on the webrev but so that I know:
- Is it normaly that you can suspend when you are in a JVMCI frame?
Yes, because it's just Java code, and we allow all Java code to be
suspended, even Graal and JVMCI code.
will/is there not a better way that we could detect that we are in a
JVMCI frame?
We could check the threads's _adjusting_comp_level flag for this
particular case, if we decided that we don't want to be able to debug
JVMCI Java code.
Is it always safe to suspend a JVMCI frame?
That's a good question. If it was grabbing any locks, then suspending
it could cause problems for other threads calling into JVMCI.
Another solution would be to do adjusting_comp_level() in a separate
thread. So I think there are at least 3 possible solutions:
1) Allow JVMCI adjusting_comp_level call to be suspended/debugged
2) Don't allow it to be suspended/debugged,
a) by running in a separate thread, or
b) don't suspend when _adjusting_comp_level flag is set
We could introduce a concept of "system Java" code, which, just like
Unix kernel code that is not debuggable without a kernel debugger, would
not normally be debuggable without setting a special flag.
CCing graal-dev alias.
dl
