/** Prints the address of the object. */
@Override
public String toString() {
if (value.isNull()) {
return "null";
}
return value.toString();
}
@Uninterruptible
public static void dumpRef(ObjectReference ref) {
VM.sysWrite("REF=");
if (ref.isNull()) {
VM.sysWrite("NULL\n");
return;
}
VM.sysWrite(ref);
if (!mappedVMRef(ref)) {
VM.sysWrite(" (REF OUTSIDE OF HEAP OR NOT MAPPED)\n");
return;
}
ObjectModel.dumpHeader(ref);
ObjectReference tib = ObjectReference.fromObject(ObjectModel.getTIB(ref));
if (!MemoryManager.mightBeTIB(tib)) {
VM.sysWrite(" (INVALID TIB: CLASS NOT ACCESSIBLE)\n");
return;
}
RVMType type = Magic.getObjectType(ref.toObject());
ObjectReference itype = ObjectReference.fromObject(type);
VM.sysWrite(" TYPE=");
VM.sysWrite(itype);
if (!validType(itype)) {
VM.sysWrite(" (INVALID TYPE: CLASS NOT ACCESSIBLE)\n");
return;
}
VM.sysWrite(" CLASS=");
VM.sysWrite(type.getDescriptor());
VM.sysWrite("\n");
}
/**
* Store a value into a reference field of an object.
*
* @param object The object to store the field of.
* @param index The field index.
* @param value The value to store.
*/
public void storeReferenceField(ObjectReference object, int index, ObjectReference value) {
int limit = ObjectModel.getRefs(object);
if (Trace.isEnabled(Item.STORE) || ObjectModel.isWatched(object)) {
Trace.printf(
Item.STORE,
"[%s].object[%d/%d] = %s",
ObjectModel.getString(object),
index,
limit,
value.toString());
}
check(!object.isNull(), "Object can not be null");
check(index >= 0, "Index must be non-negative");
check(index < limit, "Index " + index + " out of bounds " + limit);
Address referenceSlot = ObjectModel.getRefSlot(object, index);
if (ActivePlan.constraints.needsWriteBarrier()) {
context.writeBarrier(object, referenceSlot, value, null, null, Plan.AASTORE_WRITE_BARRIER);
if (gcEveryWB) {
gc();
}
} else {
referenceSlot.store(value);
}
}
/**
* Given a slot (ie the address of an ObjectReference), ensure that the referent will not move for
* the rest of the GC. This is achieved by calling the precopyObject method.
*
* @param slot The slot to check
*/
@Inline
public final void processPrecopyEdge(Address slot) {
ObjectReference child = slot.loadObjectReference();
if (!child.isNull()) {
child = precopyObject(child);
slot.store(child);
}
}
private static synchronized Throwable fillInStackTrace(Throwable instance) {
ObjectReference.fromObject(instance)
.toAddress()
.add(BACKTRACE_OFFSET)
.store(
ObjectReference.fromObject(
VmThread.getStackTrace(VmProcessor.current().getCurrentThread())));
return instance;
}
/**
* Store a value into the data field of an object.
*
* @param object The object to store the field of.
* @param index The field index.
* @param value The value to store.
*/
public void storeDataField(ObjectReference object, int index, int value) {
int limit = ObjectModel.getDataCount(object);
check(!object.isNull(), "Object can not be null");
check(index >= 0, "Index must be non-negative");
check(index < limit, "Index " + index + " out of bounds " + limit);
Address ref = ObjectModel.getDataSlot(object, index);
ref.store(value);
Trace.trace(Item.STORE, "%s.[%d] = %d", object.toString(), index, value);
}
/** All Scalars */
public static void scalar(Object object, TransitiveClosure trace) {
Address base = Magic.objectAsAddress(object);
int[] offsets = ObjectModel.getObjectType(object).asClass().getReferenceOffsets();
for (int i = 0; i < offsets.length; i++) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(offsets[i]));
}
}
/** {@inheritDoc} */
@Override
public boolean isLive(ObjectReference object) {
if (object.isNull()) return false;
if (Space.isInSpace(SS.SS0, object)) return SS.hi ? SS.copySpace0.isLive(object) : true;
if (Space.isInSpace(SS.SS1, object)) return SS.hi ? true : SS.copySpace1.isLive(object);
return super.isLive(object);
}
/**
* Push an address onto the address stack.
*
* @param object the object to be pushed onto the object queue
*/
@Inline
public final void push(ObjectReference object) {
Address addr = object.toAddress();
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr.isZero());
checkHeadInsert(1);
uncheckedHeadInsert(addr);
}
/** Reference Arrays */
public static void referenceArray(Object object, TransitiveClosure trace) {
Address base = Magic.objectAsAddress(object);
int length = ObjectModel.getArrayLength(object);
for (int i = 0; i < length; i++) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(i << LOG_BYTES_IN_ADDRESS));
}
}
/**
* Is the specified object live?
*
* @param object The object.
* @return True if the object is live.
*/
public boolean isLive(ObjectReference object) {
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(Immix.immixSpace.inImmixDefragCollection());
if (object.isNull()) return false;
if (Space.isInSpace(Immix.IMMIX, object)) {
return Immix.immixSpace.isLive(object);
}
return super.isLive(object);
}
/**
* Pop an address from the address stack, return zero if the stack is empty.
*
* @return The next address in the address stack, or zero if the stack is empty
*/
@Inline
public final ObjectReference pop() {
if (checkDequeue(1)) {
return uncheckedDequeue().toObjectReference();
} else {
return ObjectReference.nullReference();
}
}
/**
* This method is the core method during the trace of the object graph. The role of this method is
* to:
*
* <p>1. Ensure the traced object is not collected. 2. If this is the first visit to the object
* enqueue it to be scanned. 3. Return the forwarded reference to the object.
*
* <p>In this instance, we refer objects in the mark-sweep space to the immixSpace for tracing,
* and defer to the superclass for all others.
*
* @param object The object to be traced.
* @return The new reference to the same object instance.
*/
@Inline
public ObjectReference traceObject(ObjectReference object) {
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(Immix.immixSpace.inImmixDefragCollection());
if (object.isNull()) return object;
if (Space.isInSpace(Immix.IMMIX, object))
return Immix.immixSpace.traceObject(this, object, Plan.ALLOC_DEFAULT);
return super.traceObject(object);
}
private static int getStackTraceDepth(Throwable instance) {
return ((Object[])
ObjectReference.fromObject(instance)
.toAddress()
.add(BACKTRACE_OFFSET)
.loadObjectReference()
.toObject())
.length;
}
@Override
@Inline
public ObjectReference traceObject(ObjectReference object) {
if (object.isNull()) return object;
if (Space.isInSpace(SS.SS0, object))
return SS.copySpace0.traceObject(this, object, SS.ALLOC_SS);
if (Space.isInSpace(SS.SS1, object))
return SS.copySpace1.traceObject(this, object, SS.ALLOC_SS);
return super.traceObject(object);
}
/**
* Trace a reference during GC. This involves determining which collection policy applies and
* calling the appropriate <code>trace</code> method.
*
* @param target The object the interior edge points within.
* @param slot The location of the interior edge.
* @param root True if this is a root edge.
*/
public final void processInteriorEdge(ObjectReference target, Address slot, boolean root) {
Address interiorRef = slot.loadAddress();
Offset offset = interiorRef.diff(target.toAddress());
ObjectReference newTarget = traceObject(target, root);
if (VM.VERIFY_ASSERTIONS) {
if (offset.sLT(Offset.zero()) || offset.sGT(Offset.fromIntSignExtend(1 << 24))) {
// There is probably no object this large
Log.writeln("ERROR: Suspiciously large delta to interior pointer");
Log.write(" object base = ");
Log.writeln(target);
Log.write(" interior reference = ");
Log.writeln(interiorRef);
Log.write(" delta = ");
Log.writeln(offset);
VM.assertions._assert(false);
}
}
slot.store(newTarget.toAddress().plus(offset));
}
/**
* Load and return the value of a reference field of an object.
*
* @param object The object to load the field of.
* @param index The field index.
*/
public ObjectReference loadReferenceField(ObjectReference object, int index) {
int limit = ObjectModel.getRefs(object);
check(!object.isNull(), "Object can not be null");
check(index >= 0, "Index must be non-negative");
check(index < limit, "Index " + index + " out of bounds " + limit);
Address referenceSlot = ObjectModel.getRefSlot(object, index);
ObjectReference result;
if (ActivePlan.constraints.needsReadBarrier()) {
result = context.readBarrier(object, referenceSlot, null, null, Plan.AASTORE_WRITE_BARRIER);
} else {
result = referenceSlot.loadObjectReference();
}
Trace.trace(
Item.LOAD,
"[%s].object[%d] returned [%s]",
ObjectModel.getString(object),
index,
result.toString());
return result;
}
static int newGlobalRef(Object referent) {
if (VM.VerifyAssertions)
VM._assert(MemoryManager.validRef(ObjectReference.fromObject(referent)));
if (free >= JNIGlobalRefs.length()) {
AddressArray newGlobalRefs = AddressArray.create(JNIGlobalRefs.length() * 2);
copyAndReplaceGlobalRefs(newGlobalRefs);
}
JNIGlobalRefs.set(free, Magic.objectAsAddress(referent));
return -free++;
}
/**
* Load and return the value of a data field of an object.
*
* @param object The object to load the field of.
* @param index The field index.
*/
public int loadDataField(ObjectReference object, int index) {
int limit = ObjectModel.getDataCount(object);
check(!object.isNull(), "Object can not be null");
check(index >= 0, "Index must be non-negative");
check(index < limit, "Index " + index + " out of bounds " + limit);
Address dataSlot = ObjectModel.getDataSlot(object, index);
int result = dataSlot.loadInt();
Trace.trace(
Item.LOAD, "[%s].int[%d] returned [%d]", ObjectModel.getString(object), index, result);
return result;
}
/**
* This method is the core method during the trace of the object graph. The role of this method is
* to:
*
* <p>1. Ensure the traced object is not collected. 2. If this is the first visit to the object
* enqueue it to be scanned. 3. Return the forwarded reference to the object.
*
* @param object The object to be traced.
* @return The new reference to the same object instance.
*/
@Inline
public ObjectReference traceObject(ObjectReference object) {
if (Space.isInSpace(Plan.VM_SPACE, object))
return (Plan.SCAN_BOOT_IMAGE) ? object : Plan.vmSpace.traceObject(this, object);
if (Space.isInSpace(Plan.IMMORTAL, object)) return Plan.immortalSpace.traceObject(this, object);
if (Space.isInSpace(Plan.LOS, object)) return Plan.loSpace.traceObject(this, object);
if (Space.isInSpace(Plan.PLOS, object)) return Plan.ploSpace.traceObject(this, object);
if (Plan.USE_CODE_SPACE && Space.isInSpace(Plan.SMALL_CODE, object))
return Plan.smallCodeSpace.traceObject(this, object);
if (Plan.USE_CODE_SPACE && Space.isInSpace(Plan.LARGE_CODE, object))
return Plan.largeCodeSpace.traceObject(this, object);
if (VM.VERIFY_ASSERTIONS)
VM.assertions._assert(false, "No special case for space in traceObject");
return ObjectReference.nullReference();
}
private static StackTraceElement getStackTraceElement(Throwable instance, int index) {
final VmStackFrame frame =
(VmStackFrame)
((Object[])
ObjectReference.fromObject(instance)
.toAddress()
.add(BACKTRACE_OFFSET)
.loadObjectReference()
.toObject())
[index];
final String location = frame.getLocationInfo();
final int lineNumber = "?".equals(location) ? -1 : Integer.parseInt(location);
final VmMethod method = frame.getMethod();
final VmType<?> vmClass = (method == null) ? null : method.getDeclaringClass();
final String fname = (vmClass == null) ? null : vmClass.getSourceFile();
final String cname = (vmClass == null) ? "<unknown class>" : vmClass.getName();
final String mname = (method == null) ? "<unknown method>" : method.getName();
return new StackTraceElement(
cname, mname, fname, method == null || method.isNative() ? -2 : lineNumber);
}
/** Fallback */
public static void fallback(Object object, TransitiveClosure trace) {
ObjectReference objectRef = ObjectReference.fromObject(object);
RVMType type = ObjectModel.getObjectType(objectRef.toObject());
if (type.isClassType()) {
RVMClass klass = type.asClass();
int[] offsets = klass.getReferenceOffsets();
for (int i = 0; i < offsets.length; i++) {
trace.processEdge(objectRef, objectRef.toAddress().plus(offsets[i]));
}
} else if (type.isArrayType() && type.asArray().getElementType().isReferenceType()) {
for (int i = 0; i < ObjectModel.getArrayLength(objectRef.toObject()); i++) {
trace.processEdge(objectRef, objectRef.toAddress().plus(i << LOG_BYTES_IN_ADDRESS));
}
}
}
/** All patterns bottom out here */
@Inline
public static void pattern(int pattern, Object object, TransitiveClosure trace) {
Address base = Magic.objectAsAddress(object).plus(FIELD_ZERO_OFFSET);
if ((pattern & 1) != 0) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(0));
}
if ((pattern & 2) != 0) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(1 << LOG_BYTES_IN_ADDRESS));
}
if ((pattern & 4) != 0) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(2 << LOG_BYTES_IN_ADDRESS));
}
if ((pattern & 8) != 0) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(3 << LOG_BYTES_IN_ADDRESS));
}
if ((pattern & 16) != 0) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(4 << LOG_BYTES_IN_ADDRESS));
}
if ((pattern & 32) != 0) {
trace.processEdge(ObjectReference.fromObject(object), base.plus(5 << LOG_BYTES_IN_ADDRESS));
}
}
/** Use the hash code of the underlying ObjectReference */
@Override
public int hashCode() {
return value.hashCode();
}
/**
* Checks if a reference, its TIB pointer and type pointer are all in the heap.
*
* @param ref the reference to check
* @return {@code true} if and only if the reference refers to a valid object
*/
@Uninterruptible
public static boolean validObject(Object ref) {
return validRef(ObjectReference.fromObject(ref));
}
/** Construct an initially null object value */
public ObjectValue() {
this(ObjectReference.nullReference());
}
/** Get this value as a boolean. */
@Override
public boolean getBoolValue() {
return !value.isNull();
}
@Uninterruptible
public static boolean validRef(ObjectReference ref) {
if (ref.isNull()) return true;
if (!Space.isMappedObject(ref)) {
VM.sysWrite("validRef: REF outside heap, ref = ");
VM.sysWrite(ref);
VM.sysWrite("\n");
Space.printVMMap();
return false;
}
if (MOVES_OBJECTS) {
/*
TODO: Work out how to check if forwarded
if (Plan.isForwardedOrBeingForwarded(ref)) {
// TODO: actually follow forwarding pointer
// (need to bound recursion when things are broken!!)
return true;
}
*/
}
TIB tib = ObjectModel.getTIB(ref);
Address tibAddr = Magic.objectAsAddress(tib);
if (!Space.isMappedObject(ObjectReference.fromObject(tib))) {
VM.sysWrite("validRef: TIB outside heap, ref = ");
VM.sysWrite(ref);
VM.sysWrite(" tib = ");
VM.sysWrite(tibAddr);
VM.sysWrite("\n");
ObjectModel.dumpHeader(ref);
return false;
}
if (tibAddr.isZero()) {
VM.sysWrite("validRef: TIB is Zero! ");
VM.sysWrite(ref);
VM.sysWrite("\n");
ObjectModel.dumpHeader(ref);
return false;
}
if (tib.length() == 0) {
VM.sysWrite("validRef: TIB length zero, ref = ");
VM.sysWrite(ref);
VM.sysWrite(" tib = ");
VM.sysWrite(tibAddr);
VM.sysWrite("\n");
ObjectModel.dumpHeader(ref);
return false;
}
ObjectReference type = ObjectReference.fromObject(tib.getType());
if (!validType(type)) {
VM.sysWrite("validRef: invalid TYPE, ref = ");
VM.sysWrite(ref);
VM.sysWrite(" tib = ");
VM.sysWrite(Magic.objectAsAddress(tib));
VM.sysWrite(" type = ");
VM.sysWrite(type);
VM.sysWrite("\n");
ObjectModel.dumpHeader(ref);
return false;
}
return true;
} // validRef
/** Get the hash code for the given object. */
public int hash(ObjectReference object) {
check(!object.isNull(), "Object can not be null");
int result = ObjectModel.getHashCode(object);
Trace.trace(Item.HASH, "hash(%s) returned [%d]", ObjectModel.getString(object), result);
return result;
}
/**
* Return true if the object resides within the nursery
*
* @param obj The object to be tested
* @return true if the object resides within the nursery
*/
@Inline
static boolean inNursery(ObjectReference obj) {
return inNursery(obj.toAddress());
}
