Uncommon trap in OptimizedCallTarget::executeHelper

[Stefan Marr]

Hi:

On 17 Jan 2014, at 13:12, Stefan Marr <java at stefan-marr.de> wrote:

> """
> Uncommon trap   bci=0 pc=39901936, relative_pc=144, method=executeHelper, speculation=0
> <uncommon_trap thread='6403' reason='null_assert|unreached0' action='reinterpret' speculation='0' compile_id='-1' compiler='Graal' level='1' count='141' state='null_assert|unreached0 recompiled' recompiles2='140' stamp='8.999'>
> Uncommon trap occurred in com.oracle.graal.truffle.OptimizedCallTarget::executeHelper (Graal: installedCodeName=HotSpotMethod&lt;OptimizedCallTarget.executeHelper(PackedFrame, Arguments)&gt;)  (@0x000000010260daf0) thread=6403 reason=null_assert|unreached0 action=reinterpret unloaded_class_index=-1 speculation=0
> <jvms bci='0' method='com/oracle/graal/truffle/OptimizedCallTarget executeHelper (Lcom/oracle/truffle/api/frame/PackedFrame;Lcom/oracle/truffle/api/Arguments;)Ljava/lang/Object;' bytes='19' count='8139' iicount='8139' throwouts='391' decompiles='141' null_assert|unreached0_traps='141' overflow_recompiles='140'/>
> </uncommon_trap>
> “""

So, these “null_assert|unreached0” traps are haunting me.
I chased now a couple of issues, which all dead-ended in something similar to this:

Uncommon trap   bci=14 pc=285007556, relative_pc=6596, method=invoke, speculation=0
<uncommon_trap thread='6403' reason='null_assert|unreached0' action='reinterpret' speculation='0' compile_id='-1' compiler='Graal' level='1' count='119' state='null_assert|unreached0 recompiled' recompiles2='118' stamp='19.855'>
Uncommon trap occurred in com.oracle.graal.truffle.OptimizedCallTarget::executeHelper (Graal: installedCodeName=HotSpotMethod&lt;OptimizedCallTarget.executeHelper(PackedFrame, Arguments)&gt;)  (@0x0000000110fcdec4) thread=6403 reason=null_assert|unreached0 action=reinterpret unloaded_class_index=-1 speculation=0
<jvms bci='14' method='som/vmobjects/SMethod invoke (Lcom/oracle/truffle/api/frame/PackedFrame;Ljava/lang/Object;Ljava/lang/Object;Lsom/vm/Universe;)Ljava/lang/Object;' bytes='18' count='3493' iicount='3493' throwouts='133'/>
<jvms bci=’16' method='som/primitives/BlockPrims$ValueOnePrim doSBlock (Lcom/oracle/truffle/api/frame/VirtualFrame;Lsom/vmobjects/SBlock;Ljava/lang/Object;)Ljava/lang/Object;' bytes='20' count='3493' iicount='3493' throwouts='133'/>

In this particular case, we are talking about a method that looked like this:

public Object invoke(final PackedFrame caller, final Object self, final Object arg, final Universe universe) {
  return callTarget.call(caller, new BinaryArguments(self, arg));
}

No idea what’s going on here. And if I can trust the Eclipse Bytecode Outliner, then there is also no bytecode index of 14.

What is the exact meaning of that trap?
I guess something like: one branch of a null assertion was reached, that wasn’t compiled?


Thanks
Stefan


-- 
Stefan Marr
INRIA Lille - Nord Europe
http://stefan-marr.de/research/