Request for review (XS): crash in C2 when using -XX:+CountCompiledCalls

Christian Thalinger christian.thalinger at oracle.com
Fri May 18 12:16:06 PDT 2012


On May 16, 2012, at 9:12 AM, Vladimir Kozlov wrote:

> Kris,
> 
> Changes looks good. I will push it tomorrow.

I created:

7170053: crash in C2 when using -XX:+CountCompiledCalls

and will push it in a minute.  Thanks for the fix.

-- Chris

> 
> Thanks,
> Vladimir
> 
> On 5/16/12 6:02 AM, Krystal Mok wrote:
>> Hi all,
>> 
>> Could I get some reviews for this patch, please?
>> https://gist.github.com/2710000#file_count_compiled_calls.patch
>> 
>> Description:
>> 
>> C2 may crash when compiling methods with -XX:+CountCompiledCalls turned on. The cause is
>> in Parse::count_compiled_calls(), where it made a TypeInstPtr from a ciMethod:
>> 
>> const TypeInstPtr* addr_type = TypeInstPtr::make(method());
>> 
>> Since the klass of a ciMethod is a ciMethodKlass, which isn't a ciInstanceKlass, an assertion is hit later in
>> Compile::flatten_alias_type(), where it's expecting a TypeInstPtr to have a ciInstanceKlass:
>> 
>> ciInstanceKlass *k = to->klass()->as_instance_klass();
>> 
>> An example of the crash is available here: https://gist.github.com/2710000
>> In the example, I started a Groovy shell with -XX:+CountCompiledCalls set, and it crashed quickly when compiling
>> java.lang.String.charAt().
>> 
>> The fix is to use TypeOopPtr::make_from_constant(method()) instead of TypeInstPtr::make(method()).
>> I did check the hg history, and looks like it's been like this since duke at 0. Wonder if there's any history behind this.
>> 
>> Note that this fix may have to be changed again when methodOopDesc's are moved out of PermGen.
>> 
>> Regards,
>> Kris



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