Request for reviews (XS): 7087727: JSR 292: C2 crash if ScavengeRootsInCode=2 when "static final" MethodHandle constants are in use

[Christian Thalinger]

On Nov 8, 2011, at 7:12 PM, Vladimir Kozlov wrote:

> Christian,
> 
> You recently fixed other code to avoid check bytecode directly. So should you use is_method_handle_invoke() here? Or it is not correct for this place?

I wanted to do that but then I noticed that there is no easy way to get a methodHandle out of a ciMethod and left it as it is.  If you know of a good way let me know and I will change it.

-- Chris

> 
> Thanks,
> Vladimir
> 
> Christian Thalinger wrote:
>> http://cr.openjdk.java.net/~twisti/7087727/
>> 7087727: JSR 292: C2 crash if ScavengeRootsInCode=2 when "static final" MethodHandle constants are in use
>> Reviewed-by:
>> The flag setting ScavengeRootsInCode=2 causes the JIT to inline more
>> constants.  This is generally a good thing for performance, but can
>> cause bugs in compiled code.
>> The test case has a code pattern that looks similar to the
>> selectAlternative idiom but boils down to a different invoke bytecode
>> (invokevirtual in that case).  The current code in
>> PredictedDynamicCallGenerator::generate checks for invokespecial
>> (which is used by selectAlternative) and so code for invokedynamic is
>> generated (in non-debug builds) which eventually leads to a crash.
>> src/share/vm/opto/callGenerator.cpp