review (S) for 6951190: assert(!klass_is_exact(), "only non-exact klass") while building JDK

[Tom Rodriguez]

That's still not right.  I think my brain hasn't fully kicked in yet.  I'll just go with a CheckCastPP as you've suggested.

tom

On May 10, 2010, at 11:51 AM, Tom Rodriguez wrote:

> 
> On May 10, 2010, at 11:25 AM, Vladimir Kozlov wrote:
> 
>> No. It will not handle situation when statically we don't know if argument is NULL.
>> And it will no work for NULL stopped() situation since 'failure' node will be NULL
>> so merge region will not have valid paths.
> 
> You're right that I'm not handling the argument == null case properly.
> 
>> 
>> Can we just use existing code and add CheckCastPPNode cast after gen_instanceof() ?
> 
> I was trying to get rid of the use of gen_instanceof since it generates quite a rats nest of tests that can require split_if to simplify.  What about this:
> 
> diff -r 359375cb7de6 src/share/vm/opto/library_call.cpp                                                                                               
> --- a/src/share/vm/opto/library_call.cpp        Fri May 07 15:13:00 2010 -0700                                                                       
> +++ b/src/share/vm/opto/library_call.cpp        Mon May 10 11:50:19 2010 -0700                                                                       
> @@ -945,16 +945,12 @@ bool LibraryCallKit::inline_string_equal
>   ciInstanceKlass* klass = env()->String_klass();                                                                                                   
> 
>   if (!stopped()) {                                                                                                                                 
> -    Node* inst = gen_instanceof(argument, makecon(TypeKlassPtr::make(klass)));                                                                       
> -    Node* cmp  = _gvn.transform(new (C, 3) CmpINode(inst, intcon(1)));                                                                               
> -    Node* bol  = _gvn.transform(new (C, 2) BoolNode(cmp, BoolTest::ne));                                                                             
> -                                                                                                                                                     
> -    Node* inst_false = generate_guard(bol, NULL, PROB_MIN);                                                                                         
> -    //instanceOf == true, fallthrough                                                                                                               
> -                                                                                                                                                     
> -    if (inst_false != NULL) {                                                                                                                       
> -      phi->init_req(3, intcon(0));                                                                                                                   
> -      region->init_req(3, inst_false);                                                                                                               
> +    Node* inst_false = NULL;                                                                                                                         
> +    argument = gen_checkcast(argument, makecon(TypeKlassPtr::make(klass)), &inst_false);                                                             
> +    phi->init_req(3, intcon(0));                                                                                                                     
> +    region->init_req(3, inst_false ? inst_false : top());                                                                                           
> +    if (argument == null()) {                                                                                                                       
> +      set_control(top());                                                                                                                           
>     }                                                                                                                                               
>   }
> 
> tom
> 
>> 
>> Vladimir
>> 
>> Tom Rodriguez wrote:
>>> The !stopped() logic should handle that.
>>> 
>>> tom
>>> 
>>> On May 10, 2010, at 11:01 AM, Vladimir Kozlov wrote:
>>> 
>>>> Tom,
>>>> 
>>>> You need to add check for argument==null in inline_string_equal() after gen_checkcast() since it is false case.
>>>> 
>>>> Vladimir
>> 
>> 
>> Tom Rodriguez wrote:
>>> http://cr.openjdk.java.net/~never/6951190
>>> 6951190: assert(!klass_is_exact(),"only non-exact klass") while building JDK
>>> Reviewed-by:
>>> This looks to be a long standing issue with the String.equals
>>> intrinsic.  The code checks that the argument is a String but it never
>>> actually casts it to be a String.  Later on when we're processing
>>> types for the AddP for the String.count field we're looking for a
>>> field at +20 in Object which of course doesn't exist so we hit that
>>> assert.  The fix is to perform a real checkcast which includes to
>>> required cast to String.  I also added an assert to check the contract
>>> with gen_checkcast that it always returns non-null failure_control.
>>> Tested by hand with failing JDK build.
>