/*
* Copyright (c) 2013-2016, Parallel Universe Software Co. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 3.0
* as published by the Free Software Foundation.
*/
package co.paralleluniverse.common.util;
import java.lang.reflect.Constructor;
// import java.lang.reflect.Executable;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.Iterator;
import static co.paralleluniverse.common.reflection.ReflectionUtil.accessible;
import static co.paralleluniverse.common.util.Exceptions.rethrow;
/**
* This classes uses internal HotSpot data to retrieve a more detailed stacktrace from a {@link Throwable}.
*
* Works only on HotSpot, versions 8 and 9.
*
* @author pron
*/
class ExtendedStackTraceHotSpot extends ExtendedStackTrace {
/*
* hotspot/src/share/vm/classfile/javaClasses.hpp
* hotspot/src/share/vm/classfile/javaClasses.cpp
*/
private ExtendedStackTraceElement[] est;
ExtendedStackTraceHotSpot(Throwable t) {
super(t);
}
@Override
public Iterator<ExtendedStackTraceElement> iterator() {
return new Iterator<ExtendedStackTraceElement>() {
private Object chunk = getBacktrace(t);
private int j = -1;
private int i = -1;
@Override
public boolean hasNext() {
if (j + 1 >= TRACE_CHUNK_SIZE) {
j = -1;
chunk = getNext(chunk);
if (chunk == null)
return false;
}
return getDeclaringClass(chunk, j + 1) != null;
}
@Override
public ExtendedStackTraceElement next() {
return getStackTraceElement(getStackTraceElement0(++i), chunk, ++j);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
public ExtendedStackTraceElement[] get() {
synchronized (this) {
if (est == null) {
est = new ExtendedStackTraceElement[getStackTraceDepth()];
int i = 0;
for (ExtendedStackTraceElement e : this)
est[i++] = e;
}
return est;
}
}
private int getStackTraceDepth() {
Object chunk = getBacktrace(t);
int depth = 0;
if (chunk != null) {
// Iterate over chunks and count full ones
while (true) {
Object next = getNext(chunk);
if (next == null)
break;
depth += TRACE_CHUNK_SIZE;
chunk = next;
}
// Count element in remaining partial chunk. NULL value for mirror
// marks the end of the stack trace elements that are saved.
for (int j = 0; j < TRACE_CHUNK_SIZE; j++) {
Class<?> c = getDeclaringClass(chunk, j);
if (c == null)
break;
depth++;
}
}
assert depth == getStackTraceDepth0();
return depth;
}
private ExtendedStackTraceElement getStackTraceElement(int i) {
int skipChunks = i / TRACE_CHUNK_SIZE;
int j = i % TRACE_CHUNK_SIZE;
Object chunk = getBacktrace(t);
while (chunk != null && skipChunks > 0) {
chunk = getNext(chunk);
skipChunks--;
}
return getStackTraceElement(getStackTraceElement0(i), chunk, j);
}
private ExtendedStackTraceElement getStackTraceElement(StackTraceElement ste, Object chunk, int j) {
return new HotSpotExtendedStackTraceElement(ste, getDeclaringClass(chunk, j), getMethod(chunk, j), getBci(chunk, j));
}
@Override
protected Member getMethod(ExtendedStackTraceElement este) {
final HotSpotExtendedStackTraceElement heste = (HotSpotExtendedStackTraceElement) este;
Member[] ms = getMethods(heste.getDeclaringClass());
for (Member m : ms) {
if (heste.methodSlot == getSlot(m))
return m;
}
return null;
}
private class HotSpotExtendedStackTraceElement extends BasicExtendedStackTraceElement {
private final int methodSlot;
HotSpotExtendedStackTraceElement(StackTraceElement ste, Class<?> clazz, int methodSlot, int bci) {
super(ste, clazz, null, bci);
this.methodSlot = methodSlot;
}
}
private int getStackTraceDepth0() {
try {
return (Integer) getStackTraceDepth.invoke(t);
} catch (IllegalAccessException e) {
throw new AssertionError(e);
} catch (InvocationTargetException e) {
throw rethrow(e);
}
}
private StackTraceElement getStackTraceElement0(int i) {
try {
return (StackTraceElement) getStackTraceElement.invoke(t, i);
} catch (IllegalAccessException e) {
throw new AssertionError(e);
} catch (InvocationTargetException e) {
throw rethrow(e);
}
}
private static int getSlot(/*Executable*/Member m) {
try {
if (m instanceof Constructor)
return ctorSlot.getInt((Constructor) m);
else if (m instanceof Field)
return fieldSlot.getInt((Field) m);
return methodSlot.getInt((Method) m);
} catch (IllegalAccessException e) {
throw new AssertionError(e);
}
}
private static Object getBacktrace(Throwable t) {
// the JVM blocks access to Throwable.backtrace via reflection
return (Object[]) UNSAFE.getObject(t, BACKTRACE_FIELD_OFFSET);
// try {
// return (Object[]) backtrace.get(t);
// } catch (IllegalAccessException e) {
// throw new AssertionError(e);
// }
}
private static Class<?> getDeclaringClass(Object chunk, int j) {
return (Class<?>) ((Object[]) ((Object[]) chunk)[TRACE_CLASSES_OFFSET])[j];
}
private static short getMethod(Object chunk, int j) {
return ((short[]) ((Object[]) chunk)[TRACE_METHOD_OFFSET])[j];
}
private static short getBci(Object chunk, int j) {
int bciAndVersion = ((int[]) ((Object[]) chunk)[TRACE_BCIS_OFFSET])[j];
short bci = (short) (bciAndVersion >>> 16);
short version = (short) (bciAndVersion & 0xffff);
return bci;
}
private static Object getNext(Object chunk) {
return (Object[]) ((Object[]) chunk)[((Object[]) chunk).length - 1];
}
// array of arrays; each content array contains trace_chunck_size elements. trace_next_offset points to next array of arrays
private static final long BACKTRACE_FIELD_OFFSET; //
private static final int TRACE_METHOD_OFFSET = 0; // shorts -- index into class's methods; should be equal to Method.slot
private static final int TRACE_BCIS_OFFSET = 1; // ints
private static final int TRACE_CLASSES_OFFSET = 2; // object array containing classes
// private static final int TRACE_CPREFS_OFFSET = 3; // short -- index into constant pool: method name if method is null
// private static final int TRACE_NEXT_OFFSET = 4; // this elements points to next array of arrays
private static final int TRACE_CHUNK_SIZE = 32; // maximum num of elements in each array
// private static final Field backtrace; // the JVM blocks access to Throwable.backtrace via reflection
private static final Method getStackTraceDepth;
private static final Method getStackTraceElement;
private static final Field methodSlot;
private static final Field ctorSlot;
private static final Field fieldSlot;
private static final sun.misc.Unsafe UNSAFE = UtilUnsafe.getUnsafe();
static {
try {
final String javaVersion = System.getProperty("java.version");
if (!javaVersion.startsWith("1.8") && !javaVersion.startsWith("8.") && !javaVersion.startsWith("1.9") && !javaVersion.startsWith("9."))
throw new IllegalStateException("UnsupportedJavaVersion");
if (!System.getProperty("java.vm.name").toLowerCase().contains("hotspot"))
throw new IllegalStateException("Not HotSpot");
// the JVM blocks access to Throwable.backtrace via reflection
// backtrace = ReflectionUtil.accessible(Throwable.class.getDeclaredField("backtrace"));
getStackTraceDepth = accessible(Throwable.class.getDeclaredMethod("getStackTraceDepth"));
getStackTraceElement = accessible(Throwable.class.getDeclaredMethod("getStackTraceElement", int.class));
methodSlot = accessible(Method.class.getDeclaredField("slot"));
ctorSlot = accessible(Constructor.class.getDeclaredField("slot"));
fieldSlot = accessible(Field.class.getDeclaredField("slot"));
BACKTRACE_FIELD_OFFSET = guessBacktraceFieldOffset();
sanityCheck();
} catch (Exception e) {
throw new AssertionError(e);
}
}
private static long guessBacktraceFieldOffset() {
Field[] fs = Throwable.class.getDeclaredFields();
Field second = null;
for (Field f : fs) {
if (getSlot(f) == 2) {
second = f;
break;
}
}
if (second == null)
throw new IllegalStateException();
long secondOffest = UNSAFE.objectFieldOffset(second);
if (secondOffest == 16)
return 12; // compressed oops
if (secondOffest == 24)
return 16; // no compressed oops
else
throw new IllegalStateException("secondOffset: " + secondOffest); // unfamiliar
}
private static void sanityCheck() {
Throwable t = new Throwable();
Object[] chunk = (Object[]) getBacktrace(t);
if (((Object[]) chunk[TRACE_CLASSES_OFFSET]).length != TRACE_CHUNK_SIZE)
throw new IllegalStateException();
if (((short[]) chunk[TRACE_METHOD_OFFSET]).length != TRACE_CHUNK_SIZE)
throw new IllegalStateException();
if (((int[]) chunk[TRACE_BCIS_OFFSET]).length != TRACE_CHUNK_SIZE)
throw new IllegalStateException();
final Object[] nextChunk = (Object[]) getNext(chunk);
if (nextChunk != null && nextChunk.length != chunk.length)
throw new IllegalStateException();
}
}