com.sun.squawk
Class DebuggerSupport.StackInspector

java.lang.Object
  com.sun.squawk.DebuggerSupport.StackInspector

Direct Known Subclasses:

DebuggerSupport.SlotSetter

Enclosing class:

DebuggerSupport

public static class DebuggerSupport.StackInspector
extends Object

A StackInspector instance is used in conjunction with DebuggerSupport.inspectStack(com.sun.squawk.DebuggerSupport.StackInspector, com.sun.squawk.ExecutionPoint, int) to traverse one or more stack frames in a suspended thread. The values of the slots in each frame can be inspected.

Field Summary

protected boolean	doSlots Determines if the inspector should be given a chance to inspect the value of the slots in each frame.
protected VMThread	vmThread The thread whose call stack is being inspected.

Constructor Summary

protected

DebuggerSupport.StackInspector(VMThread thread, boolean doSlots) Constructor.

Method Summary

Object	getResult() Gets the result (if any) of the inspection.
Klass[]	getTypeMap(int frameNo, Object mp, int parameterCount) Figure out the type map for the given frameNo and method pointer.
void	inspectFrame(Object mp, Offset bci, int frame, Offset fo) Invoked to inspect a frame in the thread's call stack
void	inspectSlot(boolean isParameter, int slot, Klass type, long value) Invoked to inspect the value of a primitive typed slot within a frame in the thread's call stack
void	inspectSlot(boolean isParameter, int slot, Object value) Invoked to inspect the value of a reference typed slot within a frame in the thread's call stack
void	postInspection() Hooks for any inspector specific behaviour that must run after the frame inspection is completed.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

doSlots

protected final boolean doSlots

Determines if the inspector should be given a chance to inspect the value of the slots in each frame.

vmThread

protected final VMThread vmThread

The thread whose call stack is being inspected.

Constructor Detail

DebuggerSupport.StackInspector

protected DebuggerSupport.StackInspector(VMThread thread,
                                         boolean doSlots)

Constructor.

Parameters:

thread - the thread whose call stack is being inspected. This thread must be suspended at the time the inspection is performed.

doSlots - true if this inspector should be given a change to inspect the value of the slots in each frame by means of having it inspectSlot(boolean, int, java.lang.Object) methods invoked

Method Detail

inspectFrame

public void inspectFrame(Object mp,
                         Offset bci,
                         int frame,
                         Offset fo)

Invoked to inspect a frame in the thread's call stack

Parameters:

mp - the method to which the frame pertains

bci - the current bytecode index of the instruction pointer

frame - the frame's identifier within the call stack. A frame is identified by the number of frames between it and the inner most frame (i.e. the inner most frame will be 0)

fo - the frame's offset from the top of the stack

inspectSlot

public void inspectSlot(boolean isParameter,
                        int slot,
                        Object value)

Invoked to inspect the value of a reference typed slot within a frame in the thread's call stack

Parameters:

isParameter - true if the slot holds the value of a parameter

slot - the slot index

value - the value in the slot

inspectSlot

public void inspectSlot(boolean isParameter,
                        int slot,
                        Klass type,
                        long value)

Invoked to inspect the value of a primitive typed slot within a frame in the thread's call stack

Parameters:

isParameter - true if the slot holds the value of a parameter

slot - the slot index

type - int, float, long, double, address, offset or uword

value - the value in the slot

postInspection

public void postInspection()

Hooks for any inspector specific behaviour that must run after the frame inspection is completed.

getResult

public Object getResult()

Gets the result (if any) of the inspection. This is also useful for propogating exceptions out to the caller.

Returns:

a value computed as a result of the inspection

getTypeMap

public Klass[] getTypeMap(int frameNo,
                          Object mp,
                          int parameterCount)

Figure out the type map for the given frameNo and method pointer. The default implemention decodes the typemap in the method object, but that only includes ref/prim types (Object vs int). The debugger agent (SDA) gets more specific type info from the the debugger proxy.

Parameters:

frameNo -

mp -

parameterCount -

Returns:

a klass array with one klass per physical word (eg. longs and doubles will have two entries)