private static long headerSize(BasicType type) {
if (Universe.elementTypeShouldBeAligned(type)) {
return alignObjectSize(headerSizeInBytes()) / VM.getVM().getHeapWordSize();
} else {
return headerSizeInBytes() / VM.getVM().getHeapWordSize();
}
}
/** Runs the analysis algorithm */
public void run() {
if (VM.getVM().getRevPtrs() != null) {
return; // Assume already done
}
VM vm = VM.getVM();
rp = new ReversePtrs();
vm.setRevPtrs(rp);
Universe universe = vm.getUniverse();
CollectedHeap collHeap = universe.heap();
usedSize = collHeap.used();
visitedSize = 0;
// Note that an experiment to iterate the heap linearly rather
// than in recursive-descent order has been done. It turns out
// that the recursive-descent algorithm is nearly twice as fast
// due to the fact that it scans only live objects and (currently)
// only a fraction of the perm gen, namely the static fields
// contained in instanceKlasses. (Iterating the heap linearly
// would also change the semantics of the result so that
// ReversePtrs.get() would return a non-null value even for dead
// objects.) Nonetheless, the reverse pointer computation is still
// quite slow and optimization in field iteration of objects
// should be done.
if (progressThunk != null) {
// Get it started
progressThunk.heapIterationFractionUpdate(0);
}
// Allocate mark bits for heap
markBits = new MarkBits(collHeap);
// Get a hold of the object heap
heap = vm.getObjectHeap();
// Do each thread's roots
for (JavaThread thread = VM.getVM().getThreads().first();
thread != null;
thread = thread.next()) {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
thread.printThreadIDOn(new PrintStream(bos));
String threadDesc =
" in thread \"" + thread.getThreadName() + "\" (id " + bos.toString() + ")";
doStack(thread, new RootVisitor("Stack root" + threadDesc));
doJNIHandleBlock(thread.activeHandles(), new RootVisitor("JNI handle root" + threadDesc));
}
// Do global JNI handles
JNIHandles handles = VM.getVM().getJNIHandles();
doJNIHandleBlock(handles.globalHandles(), new RootVisitor("Global JNI handle root"));
doJNIHandleBlock(handles.weakGlobalHandles(), new RootVisitor("Weak global JNI handle root"));
// Do Java-level static fields
SystemDictionary sysDict = VM.getVM().getSystemDictionary();
sysDict.allClassesDo(
new SystemDictionary.ClassVisitor() {
public void visit(Klass k) {
if (k instanceof InstanceKlass) {
final InstanceKlass ik = (InstanceKlass) k;
ik.iterateStaticFields(
new DefaultOopVisitor() {
public void doOop(OopField field, boolean isVMField) {
Oop next = field.getValue(getObj());
NamedFieldIdentifier nfi =
new NamedFieldIdentifier(
"Static field \""
+ field.getID().getName()
+ "\" in class \""
+ ik.getName().asString()
+ "\"");
LivenessPathElement lp = new LivenessPathElement(null, nfi);
rp.put(lp, next);
try {
markAndTraverse(next);
} catch (AddressException e) {
System.err.print(
"RevPtrs analysis: WARNING: AddressException at 0x"
+ Long.toHexString(e.getAddress())
+ " while traversing static fields of InstanceKlass ");
ik.printValueOn(System.err);
System.err.println();
} catch (UnknownOopException e) {
System.err.println(
"RevPtrs analysis: WARNING: UnknownOopException while "
+ "traversing static fields of InstanceKlass ");
ik.printValueOn(System.err);
System.err.println();
}
}
});
}
}
});
if (progressThunk != null) {
progressThunk.heapIterationComplete();
}
// Clear out markBits
markBits = null;
}