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

Tom Rodriguez Thomas.Rodriguez at Sun.COM
Mon Feb 8 13:59:06 PST 2010

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.


> 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:
>>>>> 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

More information about the hotspot-compiler-dev mailing list