RFR(S): 8035493: JVMTI PopFrame capability must instruct compilers not to prune locals

Markus Gronlund markus.gronlund at oracle.com
Fri Feb 21 20:27:28 UTC 2014

Hi Vladimir,

You are absolutely right, many thanks for pointing it out - I should have inspected that more closely...



Thanks again
Best regards


-----Original Message-----
From: Vladimir Kozlov 
Sent: den 21 februari 2014 19:06
To: Markus Gronlund; serviceability-dev at openjdk.net; hotspot-runtime-dev; hotspot-compiler-dev at openjdk.java.net
Subject: Re: RFR(S): 8035493: JVMTI PopFrame capability must instruct compilers not to prune locals


jvmti_state_changed() produces different result than the code it replaced. If original jvmti cached values were true we did not bailout compilation regardless their current. Only with change from false to true we do that.


On 2/21/14 2:53 AM, Markus Gronlund wrote:
> Greetings,
> Kindly asking for reviews for the following changeset:
> Webrev: http://cr.openjdk.java.net/~mgronlun/8035493/webrev01/
> Bug: https://bugs.openjdk.java.net/browse/JDK-8035493
> Problem statement summary and details are outlined in bug JDK-8035493 <https://bugs.openjdk.java.net/browse/JDK-8035493> .
> Testing completed:
> nsk/jvmti/scenarios/* (this includes JVMTI Hotswap and PopFrame 
> testing)
> hotspot/test/compiler/*
> Additionals:
> I would like, if possible, if we could move away from intertwining 
> specific jvmti capabilities inside the different compilers.
> The existing code makes it difficult to evolve and extend with 
> additional instructions to the compilers, esp. if we would like to 
> pass results from higher level conditions, perhaps by combining 
> contextual data with/without JVMTI. If possible, a suggestion would be 
> the creation of a higher level interface which the ciEnv can query for compilation instructions- the implementations of this interface could then be shielded away and allow for any type of combinatorial logic - leaving the code in the compilers themselves untouched.
> Thanks in advance
> Markus

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