review request for 7130319: C2: running with -XX:+PrintOptoAssembly crashes the VM with assert(false) failed: bad tag in log

[Dean Long]

David, thanks for the review.  How many reviews do I need before I can 
commit?

dl

On 1/23/2012 7:01 PM, David Holmes wrote:
> Looks good to me.
>
> David
>
> On 24/01/2012 5:25 AM, Dean Long wrote:
>> http://cr.openjdk.java.net/~dlong/7130319/webrev.00/
>>
>> The problem is that the VM thread is trying to exit while another
>> thread is writing to the XML log. The VM thread also wants to write
>> to the log, but notices the tag stack doesn't match up. A similar
>> problem came up before (6295565) and the solution was to relax the
>> assertion if we were shutting down through JNI DestroyJavaVM. The
>> above change follows that pattern and also allows shutdown
>> through JVM_Halt.
>>
>> More details thanks to David Holmes:
>>
>> "To be clear the VMThread is writing to the log (actually closing it) as
>> part of exit_globals() while executing VM_Exit::doit. This happens after
>> it calls set_vm_exited() so we add that as a guard against doing the
>> assertion. The problem arises because the CompilerThread was in the
>> middle of some writing (as part of PrintOptoAssembly) when it entered
>> the safepoint that allows the VM to exit."
>>
>> dl
>>
>>
>>
>>