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

[Vladimir Kozlov]

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?

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
>