RFR: 8166188: G1 Needs pre barrier on dereference of weak JNI handles (original) (raw)

coleen.phillimore at oracle.com coleen.phillimore at oracle.com
Tue Feb 14 23:31:09 UTC 2017

On 2/14/17 11:26 AM, Mikael Gerdin wrote:

Hi Kim,

On 2017-02-13 05:25, Kim Barrett wrote: Here's the updated webrevs, incorporating feedback received so far.

full: http://cr.openjdk.java.net/~kbarrett/8166188/hotspot.05/ incr: http://cr.openjdk.java.net/~kbarrett/8166188/hotspot.05.inc/ I think your change is ready to go, consider it Reviewed by me. I can't really say that I think this looks good due to the fact that I'm still traumatized by JavaCallArguments and how it uses something I've come to think of as "alternative code" to handle oop parameters but that is something that I hope we can clean up at some point in the future.

I agree. Also, I'm traumatized by the external_guard template parameter in jniHandles.hpp.

Kim, thank you for making the changes I suggested, especially in the x86 code.

It looks good to me.

Coleen

Thanks for fixing this! /Mikael

For x86 and ARM I added resolvejobject functions to their respective macroAssembler files, and call those to generate the return object handling code. Merging the two cases for Sparc is harder and I'm going to leave it to someone else. I'm also leaving any such merging for other (non-Oracle) ports to their respective maintainers. Rewrote the error checking in SignatureChekker::checkobj to simplify the control flow and provide more information. Rather than conditionally selecting between ReportJNIFatalError or assert to report problems, instead just always use guarantee. Recall that we only get here if CheckJNICalls or in a debug build. This made SignatureChekker::thread unused, so removed it.

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