Request for reviews (M): 6910618: C2: Error: assert(d->is_oop(),"JVM_ArrayCopy: dst not an oop")

[Vladimir Kozlov]

Thank you, Tom

Tom Rodriguez wrote:
> s/guaranty/guaranteed/  otherwise that looks good.

Fixed.

Vladimir

> 
> tom
> 
> On Feb 8, 2010, at 4:28 PM, Vladimir Kozlov wrote:
> 
>> http://cr.openjdk.java.net/~kvn/6910618/webrev.01
>>
>> I added comment about return_oop in deoptimization.cpp.
>> And I added the regression test case. I finally made it fail
>> with current VM (have to force inlining StringBuilder::append).
>>
>> Thanks,
>> Vladimir
>>
>> Tom Rodriguez wrote:
>>> On Feb 8, 2010, at 1:44 PM, Vladimir Kozlov wrote:
>>>> Thank you, Tom
>>>>
>>>> Bytecode_invoke_at_check() does not check for allocation bytecodes
>>>> and the bug case is deoptimization on the return from the call to
>>>> OptoRuntime::new_array_C(). So I am nervous about checking only
>>>> bytecode since I may miss something.
>>> I hadn't even considered that case but your fix definitely seems right.  You might put a larger comment on return_oop indicating under what conditions it's used any what it can't be divined from the bytecodes themselves.
>>> tom
>>>> I will remove printing.
>>>>
>>>> Thanks,
>>>> Vladimir
>>>>
>>>> Tom Rodriguez wrote:
>>>>> Oh, right, wrong end of the stack.  So then why can't you get it from the bytecodes of the call site of the last scope?
>>>>> ScopeDesc* scope = chunk->at(chunk->length() - 1)->scope();
>>>>> Bytecode_invoke* invoke = Bytecode_invoke_at_check(scope->method(), scope->bci());
>>>>> if (invoke != NULL) {
>>>>> save_oop_result = invoke->result_type() == T_OBJECT;
>>>>> }
>>>>> I guess it's possible that the site is being handled in some different way such that we don't actually have a real call there, particularly if reexecute were true.  So your fix seems more right.  What do you think about dropping the =true on the printing output since it seems redundant?
>>>>> tom
>>>>> On Feb 8, 2010, at 11:50 AM, Vladimir Kozlov wrote:
>>>>>> Because it will return deoptee (caller method) and not the method
>>>>>> from which we returned already (no frame on stack).
>>>>>>
>>>>>> Vladimir
>>>>>>
>>>>>> Tom Rodriguez wrote:
>>>>>>> Why do you need to record this in the PcDesc?  Why can't you just do:
>>>>>>> chunk->at(0)->scope()->method()->return_type() == T_OBJECT
>>>>>>> tom
>>>>>>> On Feb 8, 2010, at 11:12 AM, Vladimir Kozlov wrote:
>>>>>>>> http://cr.openjdk.java.net/~kvn/6910618/webrev.00
>>>>>>>>
>>>>>>>> Fixed 6910618: C2: Error: assert(d->is_oop(),"JVM_ArrayCopy: dst not an oop")
>>>>>>>>
>>>>>>>> Problem:
>>>>>>>> If deoptimization happened on the return from a call which
>>>>>>>> which returns oop, the oop will be not updated during GC which
>>>>>>>> is triggered by scalar replaced objects reallocation.
>>>>>>>>
>>>>>>>> Solution:
>>>>>>>> Mark in PcDesc call sites which return oop (this is main part of changes)
>>>>>>>> and save the result oop across objects reallocation during deoptimization.
>>>>>>>>
>>>>>>>> Reviewed by:
>>>>>>>>
>>>>>>>> Fix verified (y/n): y, test
>>>>>>>>
>>>>>>>> Other testing:
>>>>>>>> JPRT
>>>>>>>>
>