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package sun.jvm.hotspot.runtime;

import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.utilities.Observable;
import sun.jvm.hotspot.utilities.Observer;

A JavaCallWrapper is constructed before each JavaCall and destroyed after the call. Its purpose is to allocate/deallocate a new handle block and to save/restore the last Java fp/sp. A pointer to the JavaCallWrapper is stored on the stack.

NOTE: this port is very minimal and is only designed to get frame traversal working. FIXME: we will have to add platform- specific stuff later and therefore a factory for these objects.

/** <P> A JavaCallWrapper is constructed before each JavaCall and destroyed after the call. Its purpose is to allocate/deallocate a new handle block and to save/restore the last Java fp/sp. A pointer to the JavaCallWrapper is stored on the stack. </P> <P> NOTE: this port is very minimal and is only designed to get frame traversal working. FIXME: we will have to add platform- specific stuff later and therefore a factory for these objects. </P> */
public class JavaCallWrapper extends VMObject { protected static AddressField anchorField; private static AddressField lastJavaSPField; private static AddressField lastJavaPCField; static { VM.registerVMInitializedObserver(new Observer() { public void update(Observable o, Object data) { initialize(VM.getVM().getTypeDataBase()); } }); } private static synchronized void initialize(TypeDataBase db) { Type type = db.lookupType("JavaCallWrapper"); Type anchorType = db.lookupType("JavaFrameAnchor"); anchorField = type.getAddressField("_anchor"); lastJavaSPField = anchorType.getAddressField("_last_Java_sp"); lastJavaPCField = anchorType.getAddressField("_last_Java_pc"); } public JavaCallWrapper(Address addr) { super(addr); } public Address getLastJavaSP() { return lastJavaSPField.getValue(addr.addOffsetTo(anchorField.getOffset())); } public Address getLastJavaPC() { return lastJavaPCField.getValue(addr.addOffsetTo(anchorField.getOffset())); } }