for pre-review (M): 6912064: type profiles need to be more thorough for dynamic language support

[Vladimir Kozlov]

John,

I did not find anything alarming in these changes :)
But I did not find what you did for the last two points:
 > - profiles need to be collected on invokedynamic instructions
 > - profiles should also be collected on selected non-receiver arguments of method calls

In Parse::seems_stable_comparison() there is no explanation
why for ProfileDynamicTypes CmpU and CmpP always return "true".
And add some comments about skipping diamond phi code.

Thanks,
Vladimir

John Rose wrote:
> In order to compile dynamically typed languages, the JVM needs to collect more dynamic typing profile information, and use the information it collects more completely.
> 
> Specifically:
> 
> - existing profiles on instanceof bytecodes need to be used (they are currently ignored)
> 
> - existing profiles on invocation receivers need to be used (they are currently used only in conjunction with inlining optimizations)
> 
> - certain type comparisons which appear monomorphic should be compiled to fail on uncommon traps, rather than normal slow path code
> 
> - profiles need to be collected on invokedynamic instructions
> 
> - profiles should also be collected on selected non-receiver arguments of method calls
> 
> This is a preliminary review.  The current webrev addresses only the first and third of the above points:
> 
> http://cr.openjdk.java.net/~jrose/6912064/webrev.00/
> 
> -- John