[Jikesrvm-researchers] Using Java arrays inside Mutator

[Michael G. <ge...@gm...>]

We have been trying to extend the behavior of GenMS collector.
Specifically, we are initializing a member array in its constructor (via
new[SIZE]), and accessing its .length in alloc().
The array is supposed to be an array of local allocators (derived from
BumpPointer)
But we get a null pointer exception on this. We are not using optimizations.

The stack trace is:

JikesRVM: internal error: recursive use of hardware exception registers
(exiting)
-- Stack --
   Lorg/jikesrvm/memorymanagers/mminterface/MM_Interface;
allocateSpace(Lorg/jikesrvm/memorymanagers/mminterface/Selected$Mutator;IIIII)Lorg/vmmagic/unboxed/Address;
at line 590
   Lorg/jikesrvm/memorymanagers/mminterface/MM_Interface;
allocateArray(III[Ljava/lang/Object;IIII)Ljava/lang/Object; at line 559
   Lorg/jikesrvm/runtime/VM_Runtime;
resolvedNewArray(III[Ljava/lang/Object;IIII)Ljava/lang/Object; at line 459
   Lorg/jikesrvm/runtime/VM_StackTrace; <init>(I)V at line 85
   Ljava/lang/Throwable; fillInStackTrace()Ljava/lang/Throwable; at line 106
   Ljava/lang/Throwable; <init>()V at line 50
   Ljava/lang/Exception; <init>()V at line 66
   Ljava/lang/RuntimeException; <init>()V at line 64
   Ljava/lang/NullPointerException; <init>()V at line 69
   Lorg/jikesrvm/runtime/VM_Runtime; deliverHardwareException(II)V at line
681
   <hardware trap>
   Lorg/mmtk/plan/kadgc/KADGCMutator;
alloc(IIIII)Lorg/vmmagic/unboxed/Address; at line 123
   Lorg/jikesrvm/memorymanagers/mminterface/MM_Interface;
allocateSpace(Lorg/jikesrvm/memorymanagers/mminterface/Selected$Mutator;IIIII)Lorg/vmmagic/unboxed/Address;
at line 590
   Lorg/jikesrvm/memorymanagers/mminterface/MM_Interface;
allocateArray(III[Ljava/lang/Object;IIII)Ljava/lang/Object; at line 559
   Lorg/jikesrvm/runtime/VM_Runtime;
resolvedNewArray(III[Ljava/lang/Object;IIII)Ljava/lang/Object; at line 459
   Lorg/jikesrvm/VM_CommandLineArgs$ArgReader; <init>()V at line 712
   Lorg/jikesrvm/VM_CommandLineArgs; fetchCommandLineArguments()V at line
186
   Lorg/jikesrvm/VM; finishBooting()V at line 173
   Lorg/jikesrvm/VM; boot()V at line 132


What is the problem here?

Thanks,
Michael