Examples of sun.jvm.hotspot.debugger.Address

sun.jvm.hotspot.debugger.Address

This is the bottom-most interface which abstracts address access for both debugging and introspection. In the situation of debugging a target VM, these routines can throw the specified RuntimeExceptions to indicate failure and allow recovery of the debugging system. If these are used for introspecting the current VM and implementing functionality in it, however, it is expected that these kinds of failures will not occur and, in fact, a crash will occur if the situation arises where they would have been thrown.

Addresses are immutable. Further, it was decided not to expose the representation of the Address (and provide a corresponding factory method from, for example, long to Address). Unfortunately, because of the existence of C and "reuse" of low bits of pointers, it is occasionally necessary to perform logical operations like masking off the low bits of an "address". While these operations could be used to generate arbitrary Address objects, allowing this is not the intent of providing these operations.

This interface is able to fetch all Java primitive types, addresses, oops, and C integers of arbitrary size (see @see sun.jvm.hotspot.types.CIntegerType for further discussion). Note that the result of the latter is restricted to fitting into a 64-bit value and the high-order bytes will be silently discarded if too many bytes are requested.

Implementations may have restrictions, for example that the Java-related routines may not be called until a certain point in the bootstrapping process once the sizes of the Java primitive types are known. (The current implementation has that property.)

A note of warning: in C addresses, when represented as integers, are usually represented with unsigned types. Unfortunately, there are no unsigned primitive types in Java, so care will have to be taken in the implementation of this interface if using longs as the representation for 64-bit correctness. This is not so simple for the comparison operators.

        oldSetFieldOffset = type.getField("_old_set").getOffset();
        humongousSetFieldOffset = type.getField("_humongous_set").getOffset();
    }


    public long capacity() {
        Address g1CommittedAddr = addr.addOffsetTo(g1CommittedFieldOffset);
        MemRegion g1Committed = new MemRegion(g1CommittedAddr);
        return g1Committed.byteSize();
    }

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    public long n_regions() {
        return hrs().length();
    }


    private HeapRegionSeq hrs() {
        Address hrsAddr = addr.addOffsetTo(hrsFieldOffset);
        return (HeapRegionSeq) VMObjectFactory.newObject(HeapRegionSeq.class,
                                                         hrsAddr);
    }

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        return (HeapRegionSeq) VMObjectFactory.newObject(HeapRegionSeq.class,
                                                         hrsAddr);
    }


    public G1MonitoringSupport g1mm() {
        Address g1mmAddr = g1mmField.getValue(addr);
        return (G1MonitoringSupport) VMObjectFactory.newObject(G1MonitoringSupport.class, g1mmAddr);
    }

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        Address g1mmAddr = g1mmField.getValue(addr);
        return (G1MonitoringSupport) VMObjectFactory.newObject(G1MonitoringSupport.class, g1mmAddr);
    }


    public HeapRegionSetBase oldSet() {
        Address oldSetAddr = addr.addOffsetTo(oldSetFieldOffset);
        return (HeapRegionSetBase) VMObjectFactory.newObject(HeapRegionSetBase.class,
                                                             oldSetAddr);
    }

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        return (HeapRegionSetBase) VMObjectFactory.newObject(HeapRegionSetBase.class,
                                                             oldSetAddr);
    }


    public HeapRegionSetBase humongousSet() {
        Address humongousSetAddr = addr.addOffsetTo(humongousSetFieldOffset);
        return (HeapRegionSetBase) VMObjectFactory.newObject(HeapRegionSetBase.class,
                                                             humongousSetAddr);
    }

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        regionsField = type.getAddressField("_regions");
        lengthField = type.getCIntegerField("_length");
    }


    private HeapRegion at(long index) {
        Address arrayAddr = regionsField.getValue(addr);
        // Offset of &_region[index]
        long offset = index * VM.getVM().getAddressSize();
        Address regionAddr = arrayAddr.getAddressAt(offset);
        return (HeapRegion) VMObjectFactory.newObject(HeapRegion.class,
                                                      regionAddr);
    }

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Related Classes of sun.jvm.hotspot.debugger.Address

sun.jvm.hotspot.jdi.ObjectReferenceImpl

sun.jvm.hotspot.gc_implementation.g1.HeapRegionSeq

sun.jvm.hotspot.gc_implementation.g1.G1CollectedHeap

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