src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/InstanceKlass.java
changeset 47216 71c04702a3d5
parent 46729 c62d2e8b2728
child 48166 2659c4fe8ea7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/InstanceKlass.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,1169 @@
+/*
+ * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+package sun.jvm.hotspot.oops;
+
+import java.io.*;
+import java.util.*;
+import sun.jvm.hotspot.classfile.ClassLoaderData;
+import sun.jvm.hotspot.debugger.*;
+import sun.jvm.hotspot.memory.*;
+import sun.jvm.hotspot.memory.Dictionary;
+import sun.jvm.hotspot.runtime.*;
+import sun.jvm.hotspot.types.*;
+import sun.jvm.hotspot.utilities.*;
+
+// An InstanceKlass is the VM level representation of a Java class.
+
+public class InstanceKlass extends Klass {
+  static {
+    VM.registerVMInitializedObserver(new Observer() {
+        public void update(Observable o, Object data) {
+          initialize(VM.getVM().getTypeDataBase());
+        }
+      });
+  }
+
+  // field offset constants
+  private static int ACCESS_FLAGS_OFFSET;
+  private static int NAME_INDEX_OFFSET;
+  private static int SIGNATURE_INDEX_OFFSET;
+  private static int INITVAL_INDEX_OFFSET;
+  private static int LOW_OFFSET;
+  private static int HIGH_OFFSET;
+  private static int FIELD_SLOTS;
+  private static short FIELDINFO_TAG_SIZE;
+  private static short FIELDINFO_TAG_MASK;
+  private static short FIELDINFO_TAG_OFFSET;
+
+  // ClassState constants
+  private static int CLASS_STATE_ALLOCATED;
+  private static int CLASS_STATE_LOADED;
+  private static int CLASS_STATE_LINKED;
+  private static int CLASS_STATE_BEING_INITIALIZED;
+  private static int CLASS_STATE_FULLY_INITIALIZED;
+  private static int CLASS_STATE_INITIALIZATION_ERROR;
+
+  // _misc_flags constants
+  private static int MISC_REWRITTEN;
+  private static int MISC_HAS_NONSTATIC_FIELDS;
+  private static int MISC_SHOULD_VERIFY_CLASS;
+  private static int MISC_IS_ANONYMOUS;
+  private static int MISC_IS_CONTENDED;
+  private static int MISC_HAS_NONSTATIC_CONCRETE_METHODS;
+  private static int MISC_DECLARES_NONSTATIC_CONCRETE_METHODS;
+  private static int MISC_HAS_BEEN_REDEFINED;
+  private static int MISC_HAS_PASSED_FINGERPRINT_CHECK;
+  private static int MISC_IS_SCRATCH_CLASS;
+  private static int MISC_IS_SHARED_BOOT_CLASS;
+  private static int MISC_IS_SHARED_PLATFORM_CLASS;
+  private static int MISC_IS_SHARED_APP_CLASS;
+
+  private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
+    Type type            = db.lookupType("InstanceKlass");
+    arrayKlasses         = new MetadataField(type.getAddressField("_array_klasses"), 0);
+    methods              = type.getAddressField("_methods");
+    defaultMethods       = type.getAddressField("_default_methods");
+    methodOrdering       = type.getAddressField("_method_ordering");
+    localInterfaces      = type.getAddressField("_local_interfaces");
+    transitiveInterfaces = type.getAddressField("_transitive_interfaces");
+    fields               = type.getAddressField("_fields");
+    javaFieldsCount      = new CIntField(type.getCIntegerField("_java_fields_count"), 0);
+    constants            = new MetadataField(type.getAddressField("_constants"), 0);
+    sourceDebugExtension = type.getAddressField("_source_debug_extension");
+    innerClasses         = type.getAddressField("_inner_classes");
+    sourceFileNameIndex  = new CIntField(type.getCIntegerField("_source_file_name_index"), 0);
+    nonstaticFieldSize   = new CIntField(type.getCIntegerField("_nonstatic_field_size"), 0);
+    staticFieldSize      = new CIntField(type.getCIntegerField("_static_field_size"), 0);
+    staticOopFieldCount  = new CIntField(type.getCIntegerField("_static_oop_field_count"), 0);
+    nonstaticOopMapSize  = new CIntField(type.getCIntegerField("_nonstatic_oop_map_size"), 0);
+    isMarkedDependent    = new CIntField(type.getCIntegerField("_is_marked_dependent"), 0);
+    initState            = new CIntField(type.getCIntegerField("_init_state"), 0);
+    itableLen            = new CIntField(type.getCIntegerField("_itable_len"), 0);
+    if (VM.getVM().isJvmtiSupported()) {
+      breakpoints        = type.getAddressField("_breakpoints");
+    }
+    genericSignatureIndex = new CIntField(type.getCIntegerField("_generic_signature_index"), 0);
+    miscFlags            = new CIntField(type.getCIntegerField("_misc_flags"), 0);
+    majorVersion         = new CIntField(type.getCIntegerField("_major_version"), 0);
+    minorVersion         = new CIntField(type.getCIntegerField("_minor_version"), 0);
+    headerSize           = type.getSize();
+
+    // read field offset constants
+    ACCESS_FLAGS_OFFSET            = db.lookupIntConstant("FieldInfo::access_flags_offset").intValue();
+    NAME_INDEX_OFFSET              = db.lookupIntConstant("FieldInfo::name_index_offset").intValue();
+    SIGNATURE_INDEX_OFFSET         = db.lookupIntConstant("FieldInfo::signature_index_offset").intValue();
+    INITVAL_INDEX_OFFSET           = db.lookupIntConstant("FieldInfo::initval_index_offset").intValue();
+    LOW_OFFSET                     = db.lookupIntConstant("FieldInfo::low_packed_offset").intValue();
+    HIGH_OFFSET                    = db.lookupIntConstant("FieldInfo::high_packed_offset").intValue();
+    FIELD_SLOTS                    = db.lookupIntConstant("FieldInfo::field_slots").intValue();
+    FIELDINFO_TAG_SIZE             = db.lookupIntConstant("FIELDINFO_TAG_SIZE").shortValue();
+    FIELDINFO_TAG_MASK             = db.lookupIntConstant("FIELDINFO_TAG_MASK").shortValue();
+    FIELDINFO_TAG_OFFSET           = db.lookupIntConstant("FIELDINFO_TAG_OFFSET").shortValue();
+
+    // read ClassState constants
+    CLASS_STATE_ALLOCATED = db.lookupIntConstant("InstanceKlass::allocated").intValue();
+    CLASS_STATE_LOADED = db.lookupIntConstant("InstanceKlass::loaded").intValue();
+    CLASS_STATE_LINKED = db.lookupIntConstant("InstanceKlass::linked").intValue();
+    CLASS_STATE_BEING_INITIALIZED = db.lookupIntConstant("InstanceKlass::being_initialized").intValue();
+    CLASS_STATE_FULLY_INITIALIZED = db.lookupIntConstant("InstanceKlass::fully_initialized").intValue();
+    CLASS_STATE_INITIALIZATION_ERROR = db.lookupIntConstant("InstanceKlass::initialization_error").intValue();
+
+    MISC_REWRITTEN                    = db.lookupIntConstant("InstanceKlass::_misc_rewritten").intValue();
+    MISC_HAS_NONSTATIC_FIELDS         = db.lookupIntConstant("InstanceKlass::_misc_has_nonstatic_fields").intValue();
+    MISC_SHOULD_VERIFY_CLASS          = db.lookupIntConstant("InstanceKlass::_misc_should_verify_class").intValue();
+    MISC_IS_ANONYMOUS                 = db.lookupIntConstant("InstanceKlass::_misc_is_anonymous").intValue();
+    MISC_IS_CONTENDED                 = db.lookupIntConstant("InstanceKlass::_misc_is_contended").intValue();
+    MISC_HAS_NONSTATIC_CONCRETE_METHODS      = db.lookupIntConstant("InstanceKlass::_misc_has_nonstatic_concrete_methods").intValue();
+    MISC_DECLARES_NONSTATIC_CONCRETE_METHODS = db.lookupIntConstant("InstanceKlass::_misc_declares_nonstatic_concrete_methods").intValue();
+    MISC_HAS_BEEN_REDEFINED           = db.lookupIntConstant("InstanceKlass::_misc_has_been_redefined").intValue();
+    MISC_HAS_PASSED_FINGERPRINT_CHECK = db.lookupIntConstant("InstanceKlass::_misc_has_passed_fingerprint_check").intValue();
+    MISC_IS_SCRATCH_CLASS             = db.lookupIntConstant("InstanceKlass::_misc_is_scratch_class").intValue();
+    MISC_IS_SHARED_BOOT_CLASS         = db.lookupIntConstant("InstanceKlass::_misc_is_shared_boot_class").intValue();
+    MISC_IS_SHARED_PLATFORM_CLASS     = db.lookupIntConstant("InstanceKlass::_misc_is_shared_platform_class").intValue();
+    MISC_IS_SHARED_APP_CLASS          = db.lookupIntConstant("InstanceKlass::_misc_is_shared_app_class").intValue();
+  }
+
+  public InstanceKlass(Address addr) {
+    super(addr);
+    if (getJavaFieldsCount() != getAllFieldsCount()) {
+      // Exercise the injected field logic
+      for (int i = getJavaFieldsCount(); i < getAllFieldsCount(); i++) {
+        getFieldName(i);
+        getFieldSignature(i);
+      }
+    }
+  }
+
+  private static MetadataField arrayKlasses;
+  private static AddressField  methods;
+  private static AddressField  defaultMethods;
+  private static AddressField  methodOrdering;
+  private static AddressField  localInterfaces;
+  private static AddressField  transitiveInterfaces;
+  private static AddressField fields;
+  private static CIntField javaFieldsCount;
+  private static MetadataField constants;
+  private static AddressField  sourceDebugExtension;
+  private static AddressField  innerClasses;
+  private static CIntField sourceFileNameIndex;
+  private static CIntField nonstaticFieldSize;
+  private static CIntField staticFieldSize;
+  private static CIntField staticOopFieldCount;
+  private static CIntField nonstaticOopMapSize;
+  private static CIntField isMarkedDependent;
+  private static CIntField initState;
+  private static CIntField itableLen;
+  private static AddressField breakpoints;
+  private static CIntField genericSignatureIndex;
+  private static CIntField miscFlags;
+  private static CIntField majorVersion;
+  private static CIntField minorVersion;
+
+  // type safe enum for ClassState from instanceKlass.hpp
+  public static class ClassState {
+     public static final ClassState ALLOCATED    = new ClassState("allocated");
+     public static final ClassState LOADED       = new ClassState("loaded");
+     public static final ClassState LINKED       = new ClassState("linked");
+     public static final ClassState BEING_INITIALIZED      = new ClassState("beingInitialized");
+     public static final ClassState FULLY_INITIALIZED    = new ClassState("fullyInitialized");
+     public static final ClassState INITIALIZATION_ERROR = new ClassState("initializationError");
+
+     private ClassState(String value) {
+        this.value = value;
+     }
+
+     public String toString() {
+        return value;
+     }
+
+     private String value;
+  }
+
+  public int  getInitStateAsInt() { return (int) initState.getValue(this); }
+  public ClassState getInitState() {
+     int state = getInitStateAsInt();
+     if (state == CLASS_STATE_ALLOCATED) {
+        return ClassState.ALLOCATED;
+     } else if (state == CLASS_STATE_LOADED) {
+        return ClassState.LOADED;
+     } else if (state == CLASS_STATE_LINKED) {
+        return ClassState.LINKED;
+     } else if (state == CLASS_STATE_BEING_INITIALIZED) {
+        return ClassState.BEING_INITIALIZED;
+     } else if (state == CLASS_STATE_FULLY_INITIALIZED) {
+        return ClassState.FULLY_INITIALIZED;
+     } else if (state == CLASS_STATE_INITIALIZATION_ERROR) {
+        return ClassState.INITIALIZATION_ERROR;
+     } else {
+        throw new RuntimeException("should not reach here");
+     }
+  }
+
+  // initialization state quaries
+  public boolean isLoaded() {
+     return getInitStateAsInt() >= CLASS_STATE_LOADED;
+  }
+
+  public boolean isLinked() {
+     return getInitStateAsInt() >= CLASS_STATE_LINKED;
+  }
+
+  public boolean isInitialized() {
+     return getInitStateAsInt() == CLASS_STATE_FULLY_INITIALIZED;
+  }
+
+  public boolean isNotInitialized() {
+     return getInitStateAsInt() < CLASS_STATE_BEING_INITIALIZED;
+  }
+
+  public boolean isBeingInitialized() {
+     return getInitStateAsInt() == CLASS_STATE_BEING_INITIALIZED;
+  }
+
+  public boolean isInErrorState() {
+     return getInitStateAsInt() == CLASS_STATE_INITIALIZATION_ERROR;
+  }
+
+  public int getClassStatus() {
+     int result = 0;
+     if (isLinked()) {
+        result |= JVMDIClassStatus.VERIFIED | JVMDIClassStatus.PREPARED;
+     }
+
+     if (isInitialized()) {
+        if (Assert.ASSERTS_ENABLED) {
+           Assert.that(isLinked(), "Class status is not consistent");
+        }
+        result |= JVMDIClassStatus.INITIALIZED;
+     }
+
+     if (isInErrorState()) {
+        result |= JVMDIClassStatus.ERROR;
+     }
+     return result;
+  }
+
+  // Byteside of the header
+  private static long headerSize;
+
+  public long getObjectSize(Oop object) {
+    return getSizeHelper() * VM.getVM().getAddressSize();
+  }
+
+  public long getSize() { // in number of bytes
+    long wordLength = VM.getVM().getBytesPerWord();
+    long size = getHeaderSize() +
+                (getVtableLen() +
+                 getItableLen() +
+                 getNonstaticOopMapSize()) * wordLength;
+    if (isInterface()) {
+      size += wordLength;
+    }
+    if (isAnonymous()) {
+      size += wordLength;
+    }
+    if (hasStoredFingerprint()) {
+      size += 8; // uint64_t
+    }
+    return alignSize(size);
+  }
+
+  private int getMiscFlags() {
+    return (int) miscFlags.getValue(this);
+  }
+
+  public boolean isAnonymous() {
+    return (getMiscFlags() & MISC_IS_ANONYMOUS) != 0;
+  }
+
+  public static boolean shouldStoreFingerprint() {
+    VM vm = VM.getVM();
+    if (vm.getCommandLineBooleanFlag("EnableJVMCI") && !vm.getCommandLineBooleanFlag("UseJVMCICompiler")) {
+      return true;
+    }
+    if (vm.getCommandLineBooleanFlag("DumpSharedSpaces")) {
+      return true;
+    }
+    return false;
+  }
+
+  public boolean hasStoredFingerprint() {
+    return shouldStoreFingerprint() || isShared();
+  }
+
+  public boolean isShared() {
+    VM vm = VM.getVM();
+    if (vm.isSharingEnabled()) {
+      // This is not the same implementation as the C++ function MetaspaceObj::is_shared()
+      //     bool MetaspaceObj::is_shared() const {
+      //       return MetaspaceShared::is_in_shared_space(this);
+      //     }
+      // However, MetaspaceShared::is_in_shared_space is complicated and hard to emulate in
+      // Java code, so let's do this by looking up from the shared dictionary. Of course,
+      // this works for shared InstanceKlass only and does not work for other types of
+      // MetaspaceObj in the CDS shared archive.
+      Dictionary sharedDictionary = vm.getSystemDictionary().sharedDictionary();
+      if (sharedDictionary != null) {
+        if (sharedDictionary.contains(this)) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
+  public static long getHeaderSize() { return headerSize; }
+
+  public short getFieldAccessFlags(int index) {
+    return getFields().at(index * FIELD_SLOTS + ACCESS_FLAGS_OFFSET);
+  }
+
+  public short getFieldNameIndex(int index) {
+    if (index >= getJavaFieldsCount()) throw new IndexOutOfBoundsException("not a Java field;");
+    return getFields().at(index * FIELD_SLOTS + NAME_INDEX_OFFSET);
+  }
+
+  public Symbol getFieldName(int index) {
+    int nameIndex = getFields().at(index * FIELD_SLOTS + NAME_INDEX_OFFSET);
+    if (index < getJavaFieldsCount()) {
+      return getConstants().getSymbolAt(nameIndex);
+    } else {
+      return vmSymbols.symbolAt(nameIndex);
+    }
+  }
+
+  public short getFieldSignatureIndex(int index) {
+    if (index >= getJavaFieldsCount()) throw new IndexOutOfBoundsException("not a Java field;");
+    return getFields().at(index * FIELD_SLOTS + SIGNATURE_INDEX_OFFSET);
+  }
+
+  public Symbol getFieldSignature(int index) {
+    int signatureIndex = getFields().at(index * FIELD_SLOTS + SIGNATURE_INDEX_OFFSET);
+    if (index < getJavaFieldsCount()) {
+      return getConstants().getSymbolAt(signatureIndex);
+    } else {
+      return vmSymbols.symbolAt(signatureIndex);
+    }
+  }
+
+  public short getFieldGenericSignatureIndex(int index) {
+    // int len = getFields().length();
+    int allFieldsCount = getAllFieldsCount();
+    int generic_signature_slot = allFieldsCount * FIELD_SLOTS;
+    for (int i = 0; i < allFieldsCount; i++) {
+      short flags = getFieldAccessFlags(i);
+      AccessFlags access = new AccessFlags(flags);
+      if (i == index) {
+        if (access.fieldHasGenericSignature()) {
+           return getFields().at(generic_signature_slot);
+        } else {
+          return 0;
+        }
+      } else {
+        if (access.fieldHasGenericSignature()) {
+          generic_signature_slot ++;
+        }
+      }
+    }
+    return 0;
+  }
+
+  public Symbol getFieldGenericSignature(int index) {
+    short genericSignatureIndex = getFieldGenericSignatureIndex(index);
+    if (genericSignatureIndex != 0)  {
+      return getConstants().getSymbolAt(genericSignatureIndex);
+    }
+    return null;
+  }
+
+  public short getFieldInitialValueIndex(int index) {
+    if (index >= getJavaFieldsCount()) throw new IndexOutOfBoundsException("not a Java field;");
+    return getFields().at(index * FIELD_SLOTS + INITVAL_INDEX_OFFSET);
+  }
+
+  public int getFieldOffset(int index) {
+    U2Array fields = getFields();
+    short lo = fields.at(index * FIELD_SLOTS + LOW_OFFSET);
+    short hi = fields.at(index * FIELD_SLOTS + HIGH_OFFSET);
+    if ((lo & FIELDINFO_TAG_MASK) == FIELDINFO_TAG_OFFSET) {
+      return VM.getVM().buildIntFromShorts(lo, hi) >> FIELDINFO_TAG_SIZE;
+    }
+    throw new RuntimeException("should not reach here");
+  }
+
+  // Accessors for declared fields
+  public Klass     getArrayKlasses()        { return (Klass)        arrayKlasses.getValue(this); }
+  public MethodArray  getMethods()              { return new MethodArray(methods.getValue(getAddress())); }
+
+  public MethodArray  getDefaultMethods() {
+    if (defaultMethods != null) {
+      Address addr = defaultMethods.getValue(getAddress());
+      if ((addr != null) && (addr.getAddressAt(0) != null)) {
+        return new MethodArray(addr);
+      } else {
+        return null;
+      }
+    } else {
+      return null;
+    }
+  }
+
+  public KlassArray   getLocalInterfaces()      { return new KlassArray(localInterfaces.getValue(getAddress())); }
+  public KlassArray   getTransitiveInterfaces() { return new KlassArray(transitiveInterfaces.getValue(getAddress())); }
+  public int       getJavaFieldsCount()     { return                (int) javaFieldsCount.getValue(this); }
+  public int       getAllFieldsCount()      {
+    int len = getFields().length();
+    int allFieldsCount = 0;
+    for (; allFieldsCount*FIELD_SLOTS < len; allFieldsCount++) {
+      short flags = getFieldAccessFlags(allFieldsCount);
+      AccessFlags access = new AccessFlags(flags);
+      if (access.fieldHasGenericSignature()) {
+        len --;
+      }
+    }
+    return allFieldsCount;
+  }
+  public ConstantPool getConstants()        { return (ConstantPool) constants.getValue(this); }
+  public Symbol    getSourceFileName()      { return                getConstants().getSymbolAt(sourceFileNameIndex.getValue(this)); }
+  public String    getSourceDebugExtension(){ return                CStringUtilities.getString(sourceDebugExtension.getValue(getAddress())); }
+  public long      getNonstaticFieldSize()  { return                nonstaticFieldSize.getValue(this); }
+  public long      getStaticOopFieldCount() { return                staticOopFieldCount.getValue(this); }
+  public long      getNonstaticOopMapSize() { return                nonstaticOopMapSize.getValue(this); }
+  public boolean   getIsMarkedDependent()   { return                isMarkedDependent.getValue(this) != 0; }
+  public long      getItableLen()           { return                itableLen.getValue(this); }
+  public long      majorVersion()           { return                majorVersion.getValue(this); }
+  public long      minorVersion()           { return                minorVersion.getValue(this); }
+  public Symbol    getGenericSignature()    {
+    long index = genericSignatureIndex.getValue(this);
+    if (index != 0) {
+      return getConstants().getSymbolAt(index);
+    } else {
+      return null;
+    }
+  }
+
+  // "size helper" == instance size in words
+  public long getSizeHelper() {
+    int lh = getLayoutHelper();
+    if (Assert.ASSERTS_ENABLED) {
+      Assert.that(lh > 0, "layout helper initialized for instance class");
+    }
+    return lh / VM.getVM().getAddressSize();
+  }
+
+  // same as enum InnerClassAttributeOffset in VM code.
+  public static interface InnerClassAttributeOffset {
+    // from JVM spec. "InnerClasses" attribute
+    public static final int innerClassInnerClassInfoOffset = 0;
+    public static final int innerClassOuterClassInfoOffset = 1;
+    public static final int innerClassInnerNameOffset = 2;
+    public static final int innerClassAccessFlagsOffset = 3;
+    public static final int innerClassNextOffset = 4;
+  };
+
+  public static interface EnclosingMethodAttributeOffset {
+    public static final int enclosing_method_class_index_offset = 0;
+    public static final int enclosing_method_method_index_offset = 1;
+    public static final int enclosing_method_attribute_size = 2;
+  };
+
+  // refer to compute_modifier_flags in VM code.
+  public long computeModifierFlags() {
+    long access = getAccessFlags();
+    // But check if it happens to be member class.
+    U2Array innerClassList = getInnerClasses();
+    int length = (innerClassList == null)? 0 : (int) innerClassList.length();
+    if (length > 0) {
+       if (Assert.ASSERTS_ENABLED) {
+          Assert.that(length % InnerClassAttributeOffset.innerClassNextOffset == 0 ||
+                      length % InnerClassAttributeOffset.innerClassNextOffset == EnclosingMethodAttributeOffset.enclosing_method_attribute_size,
+                      "just checking");
+       }
+       for (int i = 0; i < length; i += InnerClassAttributeOffset.innerClassNextOffset) {
+          if (i == length - EnclosingMethodAttributeOffset.enclosing_method_attribute_size) {
+              break;
+          }
+          int ioff = innerClassList.at(i +
+                         InnerClassAttributeOffset.innerClassInnerClassInfoOffset);
+          // 'ioff' can be zero.
+          // refer to JVM spec. section 4.7.5.
+          if (ioff != 0) {
+             // only look at classes that are already loaded
+             // since we are looking for the flags for our self.
+             Symbol name = getConstants().getKlassNameAt(ioff);
+
+             if (name.equals(getName())) {
+                // This is really a member class
+                access = innerClassList.at(i +
+                        InnerClassAttributeOffset.innerClassAccessFlagsOffset);
+                break;
+             }
+          }
+       } // for inner classes
+    }
+
+    // Remember to strip ACC_SUPER bit
+    return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
+  }
+
+
+  // whether given Symbol is name of an inner/nested Klass of this Klass?
+  // anonymous and local classes are excluded.
+  public boolean isInnerClassName(Symbol sym) {
+    return isInInnerClasses(sym, false);
+  }
+
+  // whether given Symbol is name of an inner/nested Klass of this Klass?
+  // anonymous classes excluded, but local classes are included.
+  public boolean isInnerOrLocalClassName(Symbol sym) {
+    return isInInnerClasses(sym, true);
+  }
+
+  private boolean isInInnerClasses(Symbol sym, boolean includeLocals) {
+    U2Array innerClassList = getInnerClasses();
+    int length = ( innerClassList == null)? 0 : (int) innerClassList.length();
+    if (length > 0) {
+       if (Assert.ASSERTS_ENABLED) {
+         Assert.that(length % InnerClassAttributeOffset.innerClassNextOffset == 0 ||
+                     length % InnerClassAttributeOffset.innerClassNextOffset == EnclosingMethodAttributeOffset.enclosing_method_attribute_size,
+                     "just checking");
+       }
+       for (int i = 0; i < length; i += InnerClassAttributeOffset.innerClassNextOffset) {
+         if (i == length - EnclosingMethodAttributeOffset.enclosing_method_attribute_size) {
+             break;
+         }
+         int ioff = innerClassList.at(i +
+                        InnerClassAttributeOffset.innerClassInnerClassInfoOffset);
+         // 'ioff' can be zero.
+         // refer to JVM spec. section 4.7.5.
+         if (ioff != 0) {
+            Symbol innerName = getConstants().getKlassNameAt(ioff);
+            Symbol myname = getName();
+            int ooff = innerClassList.at(i +
+                        InnerClassAttributeOffset.innerClassOuterClassInfoOffset);
+            // for anonymous classes inner_name_index of InnerClasses
+            // attribute is zero.
+            int innerNameIndex = innerClassList.at(i +
+                        InnerClassAttributeOffset.innerClassInnerNameOffset);
+            // if this is not a member (anonymous, local etc.), 'ooff' will be zero
+            // refer to JVM spec. section 4.7.5.
+            if (ooff == 0) {
+               if (includeLocals) {
+                  // does it looks like my local class?
+                  if (innerName.equals(sym) &&
+                     innerName.asString().startsWith(myname.asString())) {
+                     // exclude anonymous classes.
+                     return (innerNameIndex != 0);
+                  }
+               }
+            } else {
+               Symbol outerName = getConstants().getKlassNameAt(ooff);
+
+               // include only if current class is outer class.
+               if (outerName.equals(myname) && innerName.equals(sym)) {
+                  return true;
+               }
+           }
+         }
+       } // for inner classes
+       return false;
+    } else {
+       return false;
+    }
+  }
+
+  public boolean implementsInterface(Klass k) {
+    if (Assert.ASSERTS_ENABLED) {
+      Assert.that(k.isInterface(), "should not reach here");
+    }
+    KlassArray interfaces =  getTransitiveInterfaces();
+    final int len = interfaces.length();
+    for (int i = 0; i < len; i++) {
+      if (interfaces.getAt(i).equals(k)) return true;
+    }
+    return false;
+  }
+
+  boolean computeSubtypeOf(Klass k) {
+    if (k.isInterface()) {
+      return implementsInterface(k);
+    } else {
+      return super.computeSubtypeOf(k);
+    }
+  }
+
+  public void printValueOn(PrintStream tty) {
+    tty.print("InstanceKlass for " + getName().asString());
+  }
+
+  public void iterateFields(MetadataVisitor visitor) {
+    super.iterateFields(visitor);
+    visitor.doMetadata(arrayKlasses, true);
+    // visitor.doOop(methods, true);
+    // visitor.doOop(localInterfaces, true);
+    // visitor.doOop(transitiveInterfaces, true);
+      visitor.doCInt(nonstaticFieldSize, true);
+      visitor.doCInt(staticFieldSize, true);
+      visitor.doCInt(staticOopFieldCount, true);
+      visitor.doCInt(nonstaticOopMapSize, true);
+      visitor.doCInt(isMarkedDependent, true);
+      visitor.doCInt(initState, true);
+      visitor.doCInt(itableLen, true);
+    }
+
+  /*
+   *  Visit the static fields of this InstanceKlass with the obj of
+   *  the visitor set to the oop holding the fields, which is
+   *  currently the java mirror.
+   */
+  public void iterateStaticFields(OopVisitor visitor) {
+    visitor.setObj(getJavaMirror());
+    visitor.prologue();
+    iterateStaticFieldsInternal(visitor);
+    visitor.epilogue();
+
+  }
+
+  void iterateStaticFieldsInternal(OopVisitor visitor) {
+    int length = getJavaFieldsCount();
+    for (int index = 0; index < length; index++) {
+      short accessFlags    = getFieldAccessFlags(index);
+      FieldType   type   = new FieldType(getFieldSignature(index));
+      AccessFlags access = new AccessFlags(accessFlags);
+      if (access.isStatic()) {
+        visitField(visitor, type, index);
+      }
+    }
+  }
+
+  public Klass getJavaSuper() {
+    return getSuper();
+  }
+
+  public static class StaticField {
+    public AccessFlags flags;
+    public Field field;
+
+    StaticField(Field field, AccessFlags flags) {
+      this.field = field;
+      this.flags = flags;
+    }
+  }
+
+  public Field[] getStaticFields() {
+    U2Array fields = getFields();
+    int length = getJavaFieldsCount();
+    ArrayList result = new ArrayList();
+    for (int index = 0; index < length; index++) {
+      Field f = newField(index);
+      if (f.isStatic()) {
+        result.add(f);
+      }
+    }
+    return (Field[])result.toArray(new Field[result.size()]);
+  }
+
+  public void iterateNonStaticFields(OopVisitor visitor, Oop obj) {
+    if (getSuper() != null) {
+      ((InstanceKlass) getSuper()).iterateNonStaticFields(visitor, obj);
+    }
+    int length = getJavaFieldsCount();
+    for (int index = 0; index < length; index++) {
+      short accessFlags    = getFieldAccessFlags(index);
+      FieldType   type   = new FieldType(getFieldSignature(index));
+      AccessFlags access = new AccessFlags(accessFlags);
+      if (!access.isStatic()) {
+        visitField(visitor, type, index);
+      }
+    }
+  }
+
+  /** Field access by name. */
+  public Field findLocalField(Symbol name, Symbol sig) {
+    int length = getJavaFieldsCount();
+    for (int i = 0; i < length; i++) {
+      Symbol f_name = getFieldName(i);
+      Symbol f_sig  = getFieldSignature(i);
+      if (name.equals(f_name) && sig.equals(f_sig)) {
+        return newField(i);
+      }
+    }
+
+    return null;
+  }
+
+  /** Find field in direct superinterfaces. */
+  public Field findInterfaceField(Symbol name, Symbol sig) {
+    KlassArray interfaces = getLocalInterfaces();
+    int n = interfaces.length();
+    for (int i = 0; i < n; i++) {
+      InstanceKlass intf1 = (InstanceKlass) interfaces.getAt(i);
+      if (Assert.ASSERTS_ENABLED) {
+        Assert.that(intf1.isInterface(), "just checking type");
+      }
+      // search for field in current interface
+      Field f = intf1.findLocalField(name, sig);
+      if (f != null) {
+        if (Assert.ASSERTS_ENABLED) {
+          Assert.that(f.getAccessFlagsObj().isStatic(), "interface field must be static");
+        }
+        return f;
+      }
+      // search for field in direct superinterfaces
+      f = intf1.findInterfaceField(name, sig);
+      if (f != null) return f;
+    }
+    // otherwise field lookup fails
+    return null;
+  }
+
+  /** Find field according to JVM spec 5.4.3.2, returns the klass in
+      which the field is defined. */
+  public Field findField(Symbol name, Symbol sig) {
+    // search order according to newest JVM spec (5.4.3.2, p.167).
+    // 1) search for field in current klass
+    Field f = findLocalField(name, sig);
+    if (f != null) return f;
+
+    // 2) search for field recursively in direct superinterfaces
+    f = findInterfaceField(name, sig);
+    if (f != null) return f;
+
+    // 3) apply field lookup recursively if superclass exists
+    InstanceKlass supr = (InstanceKlass) getSuper();
+    if (supr != null) return supr.findField(name, sig);
+
+    // 4) otherwise field lookup fails
+    return null;
+  }
+
+  /** Find field according to JVM spec 5.4.3.2, returns the klass in
+      which the field is defined (convenience routine) */
+  public Field findField(String name, String sig) {
+    SymbolTable symbols = VM.getVM().getSymbolTable();
+    Symbol nameSym = symbols.probe(name);
+    Symbol sigSym  = symbols.probe(sig);
+    if (nameSym == null || sigSym == null) {
+      return null;
+    }
+    return findField(nameSym, sigSym);
+  }
+
+  /** Find field according to JVM spec 5.4.3.2, returns the klass in
+      which the field is defined (retained only for backward
+      compatibility with jdbx) */
+  public Field findFieldDbg(String name, String sig) {
+    return findField(name, sig);
+  }
+
+  /** Get field by its index in the fields array. Only designed for
+      use in a debugging system. */
+  public Field getFieldByIndex(int fieldIndex) {
+    return newField(fieldIndex);
+  }
+
+
+    /** Return a List of SA Fields for the fields declared in this class.
+        Inherited fields are not included.
+        Return an empty list if there are no fields declared in this class.
+        Only designed for use in a debugging system. */
+    public List getImmediateFields() {
+        // A list of Fields for each field declared in this class/interface,
+        // not including inherited fields.
+        int length = getJavaFieldsCount();
+        List immediateFields = new ArrayList(length);
+        for (int index = 0; index < length; index++) {
+            immediateFields.add(getFieldByIndex(index));
+        }
+
+        return immediateFields;
+    }
+
+    /** Return a List of SA Fields for all the java fields in this class,
+        including all inherited fields.  This includes hidden
+        fields.  Thus the returned list can contain fields with
+        the same name.
+        Return an empty list if there are no fields.
+        Only designed for use in a debugging system. */
+    public List getAllFields() {
+        // Contains a Field for each field in this class, including immediate
+        // fields and inherited fields.
+        List  allFields = getImmediateFields();
+
+        // transitiveInterfaces contains all interfaces implemented
+        // by this class and its superclass chain with no duplicates.
+
+        KlassArray interfaces = getTransitiveInterfaces();
+        int n = interfaces.length();
+        for (int i = 0; i < n; i++) {
+            InstanceKlass intf1 = (InstanceKlass) interfaces.getAt(i);
+            if (Assert.ASSERTS_ENABLED) {
+                Assert.that(intf1.isInterface(), "just checking type");
+            }
+            allFields.addAll(intf1.getImmediateFields());
+        }
+
+        // Get all fields in the superclass, recursively.  But, don't
+        // include fields in interfaces implemented by superclasses;
+        // we already have all those.
+        if (!isInterface()) {
+            InstanceKlass supr;
+            if  ( (supr = (InstanceKlass) getSuper()) != null) {
+                allFields.addAll(supr.getImmediateFields());
+            }
+        }
+
+        return allFields;
+    }
+
+
+    /** Return a List of SA Methods declared directly in this class/interface.
+        Return an empty list if there are none, or if this isn't a class/
+        interface.
+    */
+    public List getImmediateMethods() {
+      // Contains a Method for each method declared in this class/interface
+      // not including inherited methods.
+
+      MethodArray methods = getMethods();
+      int length = methods.length();
+      Object[] tmp = new Object[length];
+
+      IntArray methodOrdering = getMethodOrdering();
+      if (methodOrdering.length() != length) {
+         // no ordering info present
+         for (int index = 0; index < length; index++) {
+            tmp[index] = methods.at(index);
+         }
+      } else {
+         for (int index = 0; index < length; index++) {
+            int originalIndex = methodOrdering.at(index);
+            tmp[originalIndex] = methods.at(index);
+         }
+      }
+
+      return Arrays.asList(tmp);
+    }
+
+    /** Return a List containing an SA InstanceKlass for each
+        interface named in this class's 'implements' clause.
+    */
+    public List getDirectImplementedInterfaces() {
+        // Contains an InstanceKlass for each interface in this classes
+        // 'implements' clause.
+
+        KlassArray interfaces = getLocalInterfaces();
+        int length = interfaces.length();
+        List directImplementedInterfaces = new ArrayList(length);
+
+        for (int index = 0; index < length; index ++) {
+            directImplementedInterfaces.add(interfaces.getAt(index));
+        }
+
+        return directImplementedInterfaces;
+    }
+
+  public Klass arrayKlassImpl(boolean orNull, int n) {
+    // FIXME: in reflective system this would need to change to
+    // actually allocate
+    if (getArrayKlasses() == null) { return null; }
+    ObjArrayKlass oak = (ObjArrayKlass) getArrayKlasses();
+    if (orNull) {
+      return oak.arrayKlassOrNull(n);
+    }
+    return oak.arrayKlass(n);
+  }
+
+  public Klass arrayKlassImpl(boolean orNull) {
+    return arrayKlassImpl(orNull, 1);
+  }
+
+  public String signature() {
+     return "L" + super.signature() + ";";
+  }
+
+  /** Convenience routine taking Strings; lookup is done in
+      SymbolTable. */
+  public Method findMethod(String name, String sig) {
+    SymbolTable syms = VM.getVM().getSymbolTable();
+    Symbol nameSym = syms.probe(name);
+    Symbol sigSym  = syms.probe(sig);
+    if (nameSym == null || sigSym == null) {
+      return null;
+    }
+    return findMethod(nameSym, sigSym);
+  }
+
+  /** Find method in vtable. */
+  public Method findMethod(Symbol name, Symbol sig) {
+    return findMethod(getMethods(), name, sig);
+  }
+
+  /** Breakpoint support (see methods on Method* for details) */
+  public BreakpointInfo getBreakpoints() {
+    if (!VM.getVM().isJvmtiSupported()) {
+      return null;
+    }
+    Address addr = getAddress().getAddressAt(breakpoints.getOffset());
+    return (BreakpointInfo) VMObjectFactory.newObject(BreakpointInfo.class, addr);
+  }
+
+  public IntArray  getMethodOrdering() {
+    Address addr = getAddress().getAddressAt(methodOrdering.getOffset());
+    return (IntArray) VMObjectFactory.newObject(IntArray.class, addr);
+  }
+
+  public U2Array getFields() {
+    Address addr = getAddress().getAddressAt(fields.getOffset());
+    return (U2Array) VMObjectFactory.newObject(U2Array.class, addr);
+  }
+
+  public U2Array getInnerClasses() {
+    Address addr = getAddress().getAddressAt(innerClasses.getOffset());
+    return (U2Array) VMObjectFactory.newObject(U2Array.class, addr);
+  }
+
+
+  //----------------------------------------------------------------------
+  // Internals only below this point
+  //
+
+  private void visitField(OopVisitor visitor, FieldType type, int index) {
+    Field f = newField(index);
+    if (type.isOop()) {
+      visitor.doOop((OopField) f, false);
+      return;
+    }
+    if (type.isByte()) {
+      visitor.doByte((ByteField) f, false);
+      return;
+    }
+    if (type.isChar()) {
+      visitor.doChar((CharField) f, false);
+      return;
+    }
+    if (type.isDouble()) {
+      visitor.doDouble((DoubleField) f, false);
+      return;
+    }
+    if (type.isFloat()) {
+      visitor.doFloat((FloatField) f, false);
+      return;
+    }
+    if (type.isInt()) {
+      visitor.doInt((IntField) f, false);
+      return;
+    }
+    if (type.isLong()) {
+      visitor.doLong((LongField) f, false);
+      return;
+    }
+    if (type.isShort()) {
+      visitor.doShort((ShortField) f, false);
+      return;
+    }
+    if (type.isBoolean()) {
+      visitor.doBoolean((BooleanField) f, false);
+      return;
+    }
+  }
+
+  // Creates new field from index in fields TypeArray
+  private Field newField(int index) {
+    FieldType type = new FieldType(getFieldSignature(index));
+    if (type.isOop()) {
+     if (VM.getVM().isCompressedOopsEnabled()) {
+        return new NarrowOopField(this, index);
+     } else {
+        return new OopField(this, index);
+     }
+    }
+    if (type.isByte()) {
+      return new ByteField(this, index);
+    }
+    if (type.isChar()) {
+      return new CharField(this, index);
+    }
+    if (type.isDouble()) {
+      return new DoubleField(this, index);
+    }
+    if (type.isFloat()) {
+      return new FloatField(this, index);
+    }
+    if (type.isInt()) {
+      return new IntField(this, index);
+    }
+    if (type.isLong()) {
+      return new LongField(this, index);
+    }
+    if (type.isShort()) {
+      return new ShortField(this, index);
+    }
+    if (type.isBoolean()) {
+      return new BooleanField(this, index);
+    }
+    throw new RuntimeException("Illegal field type at index " + index);
+  }
+
+  private static Method findMethod(MethodArray methods, Symbol name, Symbol signature) {
+    int len = methods.length();
+    // methods are sorted, so do binary search
+    int l = 0;
+    int h = len - 1;
+    while (l <= h) {
+      int mid = (l + h) >> 1;
+      Method m = methods.at(mid);
+      long res = m.getName().fastCompare(name);
+      if (res == 0) {
+        // found matching name; do linear search to find matching signature
+        // first, quick check for common case
+        if (m.getSignature().equals(signature)) return m;
+        // search downwards through overloaded methods
+        int i;
+        for (i = mid - 1; i >= l; i--) {
+          Method m1 = methods.at(i);
+          if (!m1.getName().equals(name)) break;
+          if (m1.getSignature().equals(signature)) return m1;
+        }
+        // search upwards
+        for (i = mid + 1; i <= h; i++) {
+          Method m1 = methods.at(i);
+          if (!m1.getName().equals(name)) break;
+          if (m1.getSignature().equals(signature)) return m1;
+        }
+        // not found
+        if (Assert.ASSERTS_ENABLED) {
+          int index = linearSearch(methods, name, signature);
+          if (index != -1) {
+            throw new DebuggerException("binary search bug: should have found entry " + index);
+          }
+        }
+        return null;
+      } else if (res < 0) {
+        l = mid + 1;
+      } else {
+        h = mid - 1;
+      }
+    }
+    if (Assert.ASSERTS_ENABLED) {
+      int index = linearSearch(methods, name, signature);
+      if (index != -1) {
+        throw new DebuggerException("binary search bug: should have found entry " + index);
+      }
+    }
+    return null;
+  }
+
+  private static int linearSearch(MethodArray methods, Symbol name, Symbol signature) {
+    int len = (int) methods.length();
+    for (int index = 0; index < len; index++) {
+      Method m = methods.at(index);
+      if (m.getSignature().equals(signature) && m.getName().equals(name)) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  public void dumpReplayData(PrintStream out) {
+    ConstantPool cp = getConstants();
+
+    // Try to record related loaded classes
+    Klass sub = getSubklassKlass();
+    while (sub != null) {
+        if (sub instanceof InstanceKlass) {
+            out.println("instanceKlass " + sub.getName().asString());
+        }
+        sub = sub.getNextSiblingKlass();
+    }
+
+    final int length = (int) cp.getLength();
+    out.print("ciInstanceKlass " + getName().asString() + " " + (isLinked() ? 1 : 0) + " " + (isInitialized() ? 1 : 0) + " " + length);
+    for (int index = 1; index < length; index++) {
+      out.print(" " + cp.getTags().at(index));
+    }
+    out.println();
+    if (isInitialized()) {
+      Field[] staticFields = getStaticFields();
+      for (int i = 0; i < staticFields.length; i++) {
+        Field f = staticFields[i];
+        Oop mirror = getJavaMirror();
+        if (f.isFinal() && !f.hasInitialValue()) {
+          out.print("staticfield " + getName().asString() + " " +
+                    OopUtilities.escapeString(f.getID().getName()) + " " +
+                    f.getFieldType().getSignature().asString() + " ");
+          if (f instanceof ByteField) {
+            ByteField bf = (ByteField)f;
+            out.println(bf.getValue(mirror));
+          } else if (f instanceof BooleanField) {
+            BooleanField bf = (BooleanField)f;
+            out.println(bf.getValue(mirror) ? 1 : 0);
+          } else if (f instanceof ShortField) {
+            ShortField bf = (ShortField)f;
+            out.println(bf.getValue(mirror));
+          } else if (f instanceof CharField) {
+            CharField bf = (CharField)f;
+            out.println(bf.getValue(mirror) & 0xffff);
+          } else if (f instanceof IntField) {
+            IntField bf = (IntField)f;
+            out.println(bf.getValue(mirror));
+          } else  if (f instanceof LongField) {
+            LongField bf = (LongField)f;
+            out.println(bf.getValue(mirror));
+          } else if (f instanceof FloatField) {
+            FloatField bf = (FloatField)f;
+            out.println(Float.floatToRawIntBits(bf.getValue(mirror)));
+          } else if (f instanceof DoubleField) {
+            DoubleField bf = (DoubleField)f;
+            out.println(Double.doubleToRawLongBits(bf.getValue(mirror)));
+          } else if (f instanceof OopField) {
+            OopField bf = (OopField)f;
+
+            Oop value = bf.getValue(mirror);
+            if (value == null) {
+              out.println("null");
+            } else if (value.isInstance()) {
+              Instance inst = (Instance)value;
+              if (inst.isA(SystemDictionary.getStringKlass())) {
+                out.println("\"" + OopUtilities.stringOopToEscapedString(inst) + "\"");
+              } else {
+                out.println(inst.getKlass().getName().asString());
+              }
+            } else if (value.isObjArray()) {
+              ObjArray oa = (ObjArray)value;
+              Klass ek = (ObjArrayKlass)oa.getKlass();
+              out.println(oa.getLength() + " " + ek.getName().asString());
+            } else if (value.isTypeArray()) {
+              TypeArray ta = (TypeArray)value;
+              out.println(ta.getLength());
+            } else {
+              out.println(value);
+            }
+          }
+        }
+      }
+    }
+  }
+}