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

Vladimir Kozlov vladimir.kozlov at oracle.com
Wed May 16 09:12:53 PDT 2012


Kris,

Changes looks good. I will push it tomorrow.

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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