review (XS): 7047491: C1: registers saved incorrectly when calling checkcast_arraycopy stub

[Igor Veresov]

Thanks Tom and Roland!

igor

On 5/26/11 9:39 AM, Tom Rodriguez wrote:
>
> On May 26, 2011, at 2:38 AM, Roland Westrelin wrote:
>
>>> Hm, I just assumed it's there because previous code used it. Now that I
>>> look at it I don't even see how it worked in 32bit. The space on stack
>>> is allocated in java_calling_convention() which is called from
>>> ArrayCopyStub::emit_code(). So even in 32bit there should be only space
>>> on stack for 3 out of 5 arguments, yet 5 slots are used. Perhaps we get
>>> it adjusted but I don't see how...
>>
>> _reserved_argument_area_size in FrameMap is initialized with an argument passed to the constructor. The argument is MAX2(4, hir()->max_stack()) (see Compilation::compile_java_method()). I think that's what guarantees that there's space on the stack for 5 arguments, the number of arguments to System.arraycopy()
>
> My fuzzy memory said it was something like that.  Thanks for confirming.  Looks good.
>
> tom
>
>>
>> Roland.
>