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

Krystal Mok rednaxelafx at
Wed May 16 06:02:02 PDT 2012

Hi all,

Could I get some reviews for this patch, please?


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 *k = to->klass()->as_instance_klass();

An example of the crash is available here:
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.

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