another question about megamorphic call sites in combination with MethodHandles

[Jochen Theodorou]

Am 21.03.2013 20:31, schrieb Krystal Mo:
> Hi Jochen,
>
> At least with the current tip version of HotSpot, the
> mh.invokeWithArguments() callsite is not likely to get its actual target
> inlined into the caller; we depended a lot on being able to prove that
> the MethodHandle is a (JIT-)compiled-time constant to be able to do
> inlining across the MethodHandle.invoke/invokeExact boundary.

ah yes, I forgot that.

> I'm working on adding profiling support for
> MethodHandle.invoke/invokeExact (which invokeWithArguments() will call),
> and it looks at what MethodHandles get passed in.
> When that work lands in HotSpot, your example will be a source of
> profile pollution just like the well-known megamorphic callsites in the
> old days, so I wouldn't suggest doing that.

ok, thanks. I guessed it would be.

but maybe some can give my an alternative solution then. My "problem" is 
that if you have a Java program (1.7) and that is supposed to call 
something available as MethodHandle, and several of these, then you have 
either a big useless try-catch or several of them, bloating your code a 
lot. My idea with

> public static Object invoke(MethodHandle mh, Object[] args) {
>     try {
>       return mv.invokeWithArguments(args);
>     } catch (Throwable th) {
>       ExceptionUtils.sneakyThrow(th);
>     }
> }

was to give an alternative way of calling, without having to try-catch 
every time. Then sam conversion seems to be the only way left for this.

bye blackdrag

-- 
Jochen "blackdrag" Theodorou - Groovy Project Tech Lead
blog: http://blackdragsview.blogspot.com/
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