Package com.oracle.truffle.api.instrumentation

Interface AllocationListener

public interface AllocationListener

Listener to be notified about guest language value allocations. Calls to this listener are initiated by AllocationReporter.

Use Instrumenter.attachAllocationListener(com.oracle.truffle.api.instrumentation.AllocationEventFilter, com.oracle.truffle.api.instrumentation.AllocationListener) to register an implementation of this listener. Use EventBinding.dispose() to unregister.

The listener gets called before the actual allocation and right after it. The calls to these methods are always in pairs, unless the programs crashes in between. Nested allocations are supported, several calls to onEnter prior every sub-value allocation can be followed by the appropriate number of onReturnValue calls after the sub-values are allocated, in the opposite order.

Since:

0.27

See Also:

• Instrumenter.attachAllocationListener(com.oracle.truffle.api.instrumentation.AllocationEventFilter, com.oracle.truffle.api.instrumentation.AllocationListener)
• AllocationReporter

Method Summary

Modifier and Type	Method	Description
void	onEnter(AllocationEvent event)	Notifies about an intent to allocate or re-allocate a guest language value.
void	onReturnValue(AllocationEvent event)	Notifies about an allocated guest language value.

Method Details

onEnter

void onEnter(AllocationEvent event)

Notifies about an intent to allocate or re-allocate a guest language value. This method is called prior to the actual allocation and is followed by a call to onReturnValue(com.oracle.truffle.api.instrumentation.AllocationEvent) after the successful allocation.

Parameters:

event - the event describing the intended allocation

Since:

0.27

onReturnValue

void onReturnValue(AllocationEvent event)

Notifies about an allocated guest language value. This method is called after a preceding onEnter(com.oracle.truffle.api.instrumentation.AllocationEvent) call and right after the allocation is performed. When onEnter provided a non-null value in the event, it was re-allocated and the same value instance is in this event.

Parameters:

event - the event describing the finished allocation

Since:

0.27