Module openj9.dtfj
Package com.ibm.j9ddr.vm29.j9.gc

Class GCObjectModel

java.lang.Object
com.ibm.j9ddr.vm29.j9.gc.GCBase
com.ibm.j9ddr.vm29.j9.gc.GCObjectModel
public abstract class GCObjectModel extends GCBase

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected com.ibm.j9ddr.vm29.j9.gc.GCArrayObjectModel
    indexableObjectModel
     
    protected com.ibm.j9ddr.vm29.j9.gc.GCMixedObjectModel
    mixedObjectModel
     

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    GCObjectModel()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract UDATA
    adjustSizeInBytes(UDATA sizeInBytes)
    Object size should be at least minimumConsumedSize and 8 byte aligned.
    static GCObjectModel
    from()
    Factory method to construct an appropriate object model.
    abstract U32
    getAge(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the age of an object.
    abstract UDATA
    getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz)
    Returns the shape of a class.
    abstract UDATA
    getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the shape of an object.
    abstract UDATA
    getConsumedSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Same as getSizeInBytesWithHeader, except it takes into account object alignment and minimum object size
    UDATA
    getConsumedSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Same as getSizeInSlotsWithHeader, except it takes into account object alignment and minimum object size
    UDATA
    getDataSizeInBytes(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer array)
    Returns the size of data in an indexable object, in bytes, including leaves, excluding the header.
    abstract VoidPointer
    getElementAddress(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer indexableObjectPointer, int elementIndex, int elementSize)
    Returns the address of the element at elementIndex logical offset into indexableObjectPointer, assuming that each element is dataSize bytes.
    abstract UDATA
    getHashcodeOffset(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
     
    abstract UDATA
    getHeaderSize(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size of an object header, in bytes.
    abstract long
    getObjectAlignmentInBytes()
    Returns run-time object alignment in bytes.
    abstract I32
    getObjectHashCode(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Determine the basic hash code for the specified object.
    abstract UDATA
    getRememberedBits(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the collector bits from object's header.
    abstract long
    getScanType(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
     
    abstract UDATA
    getSizeInBytesHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size in bytes of a hole object.
    abstract UDATA
    getSizeInBytesMultiSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size, in bytes, of a multi-slot hole object.
    abstract UDATA
    getSizeInBytesSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size, in bytes, of a single slot hole object.
    abstract UDATA
    getSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size of an object, in bytes, including the header.
    abstract UDATA
    getSizeInElements(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size of an indexable object in elements.
    UDATA
    getSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns the size of an object, in slots, including the header.
    abstract UDATA
    getTotalFootprintInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Get the total footprint of an object, in bytes, including the object header and all data.
    abstract boolean
    hasBeenHashed(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object has been hashed, FALSE otherwise.
    abstract boolean
    hasBeenMoved(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object has been moved after being hashed, FALSE otherwise.
    abstract boolean
    isDarkMatterObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object is dark matter, FALSE otherwise.
    abstract boolean
    isHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object is a hole, FALSE otherwise.
    abstract boolean
    isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz)
    Returns TRUE if an class is indexable, FALSE otherwise.
    abstract boolean
    isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object is indexable, FALSE otherwise.
    boolean
    isInlineContiguousArraylet(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer arrayPtr)
     
    abstract boolean
    isOld(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object is old, FALSE otherwise.
    abstract boolean
    isRemembered(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object is remembered, FALSE otherwise.
    abstract boolean
    isSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
    Returns TRUE if an object is a single slot hole object, FALSE otherwise.

    Methods declared in class com.ibm.j9ddr.vm29.j9.gc.GCBase

    getExtensions, getJavaVM

    Methods declared in class java.lang.Object

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

  • Field Details

    • mixedObjectModel

      protected com.ibm.j9ddr.vm29.j9.gc.GCMixedObjectModel mixedObjectModel

    • indexableObjectModel

      protected com.ibm.j9ddr.vm29.j9.gc.GCArrayObjectModel indexableObjectModel

  • Constructor Details

  • Method Details

    • from

      public static GCObjectModel from() throws CorruptDataException
      Factory method to construct an appropriate object model.
      Parameters:
      structure - the J9JavaVM structure to use
      Returns:
      an instance of ObjectModel
      Throws:
      CorruptDataException

    • adjustSizeInBytes

      public abstract UDATA adjustSizeInBytes(UDATA sizeInBytes)
      Object size should be at least minimumConsumedSize and 8 byte aligned.
      Parameters:
      sizeInBytes - Real size of an object
      Returns:
      Adjusted size

    • getClassShape

      public abstract UDATA getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the shape of an object.
      Parameters:
      object - Pointer to object whose shape is required.
      Returns:
      The shape of the object
      Throws:
      CorruptDataException

    • getClassShape

      public abstract UDATA getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz) throws CorruptDataException
      Returns the shape of a class.
      Parameters:
      clazz - Pointer to J9ClassPointer whose shape is required.
      Returns:
      The shape of the class
      Throws:
      CorruptDataException

    • isIndexable

      public abstract boolean isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object is indexable, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object is indexable, FALSE otherwise
      Throws:
      CorruptDataException

    • isIndexable

      public abstract boolean isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz) throws CorruptDataException
      Returns TRUE if an class is indexable, FALSE otherwise.
      Parameters:
      clazz - Pointer to an J9Class
      Returns:
      TRUE if an class is indexable, FALSE otherwise
      Throws:
      CorruptDataException

    • isHoleObject

      public abstract boolean isHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object is a hole, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object is a hole, FALSE otherwise
      Throws:
      CorruptDataException

    • isSingleSlotHoleObject

      public abstract boolean isSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object is a single slot hole object, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object is a single slot hole object, FALSE otherwise
      Throws:
      CorruptDataException

    • getSizeInBytesMultiSlotHoleObject

      public abstract UDATA getSizeInBytesMultiSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the size, in bytes, of a multi-slot hole object.
      Parameters:
      object - Pointer to an object
      Returns:
      The size, in bytes, of a multi-slot hole object
      Throws:
      CorruptDataException

    • getSizeInBytesSingleSlotHoleObject

      public abstract UDATA getSizeInBytesSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
      Returns the size, in bytes, of a single slot hole object.
      Parameters:
      object - Pointer to an object
      Returns:
      The size, in bytes, of a single slot hole object

    • getObjectAlignmentInBytes

      public abstract long getObjectAlignmentInBytes()
      Returns run-time object alignment in bytes.
      Returns:
      The alignment in bytes

    • getSizeInBytesHoleObject

      public abstract UDATA getSizeInBytesHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the size in bytes of a hole object.
      Parameters:
      object - Pointer to an object
      Returns:
      The size in bytes of a hole object
      Throws:
      CorruptDataException

    • isDarkMatterObject

      public abstract boolean isDarkMatterObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object is dark matter, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object is dark matter, FALSE otherwise
      Throws:
      CorruptDataException

    • getSizeInBytesWithHeader

      public abstract UDATA getSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the size of an object, in bytes, including the header.
      Parameters:
      object - Pointer to an object
      Returns:
      The size of an object, in bytes, including the header
      Throws:
      CorruptDataException

    • getTotalFootprintInBytesWithHeader

      public abstract UDATA getTotalFootprintInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Get the total footprint of an object, in bytes, including the object header and all data. If the object has a discontiguous representation, this method should return the size of the root object plus the total of all the discontiguous parts of the object.
      Parameters:
      object - Pointer to an object
      Returns:
      the total size of an object, in bytes, including discontiguous parts
      Throws:
      CorruptDataException

    • getConsumedSizeInBytesWithHeader

      public abstract UDATA getConsumedSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Same as getSizeInBytesWithHeader, except it takes into account object alignment and minimum object size
      Parameters:
      object - Pointer to an object
      Returns:
      The consumed heap size of an object, in bytes, including the header
      Throws:
      CorruptDataException

    • getSizeInSlotsWithHeader

      public UDATA getSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the size of an object, in slots, including the header.
      Parameters:
      object - Pointer to an object
      Returns:
      The size of an object, in slots, including the header
      Throws:
      CorruptDataException

    • getConsumedSizeInSlotsWithHeader

      public UDATA getConsumedSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Same as getSizeInSlotsWithHeader, except it takes into account object alignment and minimum object size
      Parameters:
      object - Pointer to an object
      Returns:
      The consumed heap size of an object, in slots, including the header
      Throws:
      CorruptDataException

    • getAge

      public abstract U32 getAge(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the age of an object.
      Parameters:
      object - Pointer to an object
      Returns:
      The age of the object
      Throws:
      CorruptDataException

    • isRemembered

      public abstract boolean isRemembered(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object is remembered, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object is remembered, FALSE otherwise
      Throws:
      CorruptDataException

    • getRememberedBits

      public abstract UDATA getRememberedBits(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the collector bits from object's header.
      Parameters:
      object - Pointer to an object
      Returns:
      collector bits
      Throws:
      CorruptDataException

    • isOld

      public abstract boolean isOld(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object is old, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object is in the old area, FALSE otherwise
      Throws:
      CorruptDataException

    • getSizeInElements

      public abstract UDATA getSizeInElements(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws IllegalArgumentException, CorruptDataException
      Returns the size of an indexable object in elements.
      Parameters:
      array - Pointer to the indexable object whose size is required
      Returns:
      Size of object in elements
      Throws:
      IllegalArgumentException - if the object is not an array
      CorruptDataException

    • getScanType

      public abstract long getScanType(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Throws:
      CorruptDataException

    • hasBeenHashed

      public abstract boolean hasBeenHashed(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object has been hashed, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object has been hashed, FALSE otherwise
      Throws:
      CorruptDataException

    • hasBeenMoved

      public abstract boolean hasBeenMoved(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns TRUE if an object has been moved after being hashed, FALSE otherwise.
      Parameters:
      object - Pointer to an object
      Returns:
      TRUE if an object has been moved after being hashed, FALSE otherwise
      Throws:
      CorruptDataException

    • getObjectHashCode

      public abstract I32 getObjectHashCode(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Determine the basic hash code for the specified object.
      Parameters:
      object - [in] the object to be hashed
      Returns:
      the persistent, basic hash code for the object
      Throws:
      CorruptDataException

    • getHashcodeOffset

      public abstract UDATA getHashcodeOffset(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Throws:
      CorruptDataException

    • getDataSizeInBytes

      public UDATA getDataSizeInBytes(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer array) throws CorruptDataException
      Returns the size of data in an indexable object, in bytes, including leaves, excluding the header.
      Parameters:
      array - Pointer to the indexable object whose size is required
      Returns:
      The size of an object in bytes excluding the header
      Throws:
      CorruptDataException

    • getHeaderSize

      public abstract UDATA getHeaderSize(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object) throws CorruptDataException
      Returns the size of an object header, in bytes.
      Parameters:
      object - Pointer to an object
      Returns:
      The size of an object header, in bytes.
      Throws:
      CorruptDataException

    • getElementAddress

      public abstract VoidPointer getElementAddress(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer indexableObjectPointer, int elementIndex, int elementSize) throws CorruptDataException
      Returns the address of the element at elementIndex logical offset into indexableObjectPointer, assuming that each element is dataSize bytes.
      Parameters:
      indexableObjectPointer - The array from which we should look-up the address
      elementIndex - The logical index number of the element within the array
      elementSize - The size, in bytes, of a single element of the array
      Returns:
      A pointer to the element
      Throws:
      CorruptDataException

    • isInlineContiguousArraylet

      public boolean isInlineContiguousArraylet(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer arrayPtr) throws CorruptDataException
      Parameters:
      arrayPtr - array object we are checking for isInlineContiguousArraylet
      Throws:
      CorruptDataException - If there's a problem accessing the layout of the indexable object