Java example source code file (JavaThread.java)

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Java - Java tags/keywords

address, addressfield, blocked_trans, debug, frame, in_java, in_java_trans, in_native_trans, in_vm_trans, javathread, javavframe, new_trans, oop, registermap, util

The JavaThread.java Java example source code

/*
 * Copyright (c) 2000, 2013, 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.runtime;

import java.io.*;
import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.utilities.*;

/** This is an abstract class because there are certain OS- and
    CPU-specific operations (like the setting and getting of the last
    Java frame pointer) which need to be factored out. These
    operations are implemented by, for example,
    SolarisSPARCJavaThread, and the concrete subclasses are
    instantiated by the JavaThreadFactory in the Threads class. */

public class JavaThread extends Thread {
  private static final boolean DEBUG = System.getProperty("sun.jvm.hotspot.runtime.JavaThread.DEBUG") != null;

  private static AddressField  nextField;
  private static sun.jvm.hotspot.types.OopField threadObjField;
  private static AddressField  anchorField;
  private static AddressField  lastJavaSPField;
  private static AddressField  lastJavaPCField;
  private static CIntegerField threadStateField;
  private static AddressField  osThreadField;
  private static AddressField  stackBaseField;
  private static CIntegerField stackSizeField;

  private static JavaThreadPDAccess access;

  // JavaThreadStates read from underlying process
  private static int           UNINITIALIZED;
  private static int           NEW;
  private static int           NEW_TRANS;
  private static int           IN_NATIVE;
  private static int           IN_NATIVE_TRANS;
  private static int           IN_VM;
  private static int           IN_VM_TRANS;
  private static int           IN_JAVA;
  private static int           IN_JAVA_TRANS;
  private static int           BLOCKED;
  private static int           BLOCKED_TRANS;

  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("JavaThread");
    Type anchorType = db.lookupType("JavaFrameAnchor");

    nextField         = type.getAddressField("_next");
    threadObjField    = type.getOopField("_threadObj");
    anchorField       = type.getAddressField("_anchor");
    lastJavaSPField   = anchorType.getAddressField("_last_Java_sp");
    lastJavaPCField   = anchorType.getAddressField("_last_Java_pc");
    threadStateField  = type.getCIntegerField("_thread_state");
    osThreadField     = type.getAddressField("_osthread");
    stackBaseField    = type.getAddressField("_stack_base");
    stackSizeField    = type.getCIntegerField("_stack_size");

    UNINITIALIZED     = db.lookupIntConstant("_thread_uninitialized").intValue();
    NEW               = db.lookupIntConstant("_thread_new").intValue();
    NEW_TRANS         = db.lookupIntConstant("_thread_new_trans").intValue();
    IN_NATIVE         = db.lookupIntConstant("_thread_in_native").intValue();
    IN_NATIVE_TRANS   = db.lookupIntConstant("_thread_in_native_trans").intValue();
    IN_VM             = db.lookupIntConstant("_thread_in_vm").intValue();
    IN_VM_TRANS       = db.lookupIntConstant("_thread_in_vm_trans").intValue();
    IN_JAVA           = db.lookupIntConstant("_thread_in_Java").intValue();
    IN_JAVA_TRANS     = db.lookupIntConstant("_thread_in_Java_trans").intValue();
    BLOCKED           = db.lookupIntConstant("_thread_blocked").intValue();
    BLOCKED_TRANS     = db.lookupIntConstant("_thread_blocked_trans").intValue();
  }

  public JavaThread(Address addr) {
    super(addr);
  }

  void setThreadPDAccess(JavaThreadPDAccess access) {
    this.access = access;
  }

  public JavaThread next() {
    Address threadAddr = nextField.getValue(addr);
    if (threadAddr == null) {
      return null;
    }

    return VM.getVM().getThreads().createJavaThreadWrapper(threadAddr);
  }

  /** NOTE: for convenience, this differs in definition from the
      underlying VM. Only "pure" JavaThreads return true;
      CompilerThreads and JVMDIDebuggerThreads return false. FIXME:
      consider encapsulating platform-specific functionality in an
      object instead of using inheritance (which is the primary reason
      we can't traverse CompilerThreads, etc; didn't want to have, for
      example, "SolarisSPARCCompilerThread".) */
  public boolean isJavaThread() { return true; }

  public static AddressField getAnchorField() { return anchorField; }

  /** Get the last Java stack pointer */
  public Address getLastJavaSP() {
    Address sp = lastJavaSPField.getValue(addr.addOffsetTo(anchorField.getOffset()));
    return sp;
  }

  public Address getLastJavaPC() {
    Address pc = lastJavaPCField.getValue(addr.addOffsetTo(anchorField.getOffset()));
    return pc;
  }

  /** Abstract accessor to last Java frame pointer, implemented by
      OS/CPU-specific JavaThread implementation. May return null if
      there is no frame pointer or if it is not necessary on this
      platform. */
  public Address getLastJavaFP(){
        return access.getLastJavaFP(addr);
  }

  /** Abstract accessor to last Java pc, implemented by
      OS/CPU-specific JavaThread implementation. May return null if
      there is no frame pointer or if it is not necessary on this
      platform. */

  /*
  public Address getLastJavaPC(){
        return access.getLastJavaPC(addr);
  }
  */

  // FIXME: not yet implementable
  //  public abstract void    setLastJavaFP(Address fp);

  /** A stack pointer older than any java frame stack pointer. Only
      needed on some platforms; for example, see
      thread_solaris_sparc.hpp. */
  public Address getBaseOfStackPointer(){
        return access.getBaseOfStackPointer(addr);
  }
  // FIXME: not yet implementable
  //  public abstract void    setBaseOfStackPointer(Address fp);

  /** Tells whether the last Java frame is set */
  public boolean hasLastJavaFrame() {
    return (getLastJavaSP() != null);
  }

  /** Accessing frames */
  public Frame getLastFrame() {
    // FIXME: would need to implement runtime routine
    // "cacheStatePD(boolean)" for reflective system to be able to
    // flush register windows on SPARC
    return cookLastFrame(getLastFramePD());
  }

  /** Internal routine implemented by platform-dependent subclasses */
  protected Frame getLastFramePD(){
        return access.getLastFramePD(this, addr);
  }

  /** Accessing frames. Returns the last Java VFrame or null if none
      was present. (NOTE that this is mostly unusable in a debugging
      system; see getLastJavaVFrameDbg, below, which provides very
      different functionality.) */
  public JavaVFrame getLastJavaVFrame(RegisterMap regMap) {
    if (Assert.ASSERTS_ENABLED) {
      Assert.that(regMap != null, "a map must be given");
    }
    Frame f = getLastFrame();
    if (f == null) {
      return null;
    }
    for (VFrame vf = VFrame.newVFrame(f, regMap, this); vf != null; vf = vf.sender()) {
      if (vf.isJavaFrame()) {
        return (JavaVFrame) vf;
      }
    }
    return null;
  }

  /** This should only be used by a debugger. Uses the current frame
      guess to attempt to get the topmost JavaVFrame.
      (getLastJavaVFrame, as a port of the VM's routine, assumes the
      VM is at a safepoint.) */
  public JavaVFrame getLastJavaVFrameDbg() {
    RegisterMap regMap = newRegisterMap(true);
    sun.jvm.hotspot.runtime.Frame f = getCurrentFrameGuess();
    if (f == null) return null;
    boolean imprecise = true;
    if (f.isInterpretedFrame() && !f.isInterpretedFrameValid()) {
       if (DEBUG) {
         System.out.println("Correcting for invalid interpreter frame");
       }
       f = f.sender(regMap);
       imprecise = false;
    }
    VFrame vf = VFrame.newVFrame(f, regMap, this, true, imprecise);
    if (vf == null) {
      if (DEBUG) {
        System.out.println(" (Unable to create vframe for topmost frame guess)");
      }
      return null;
    }
    return vf.isJavaFrame() ? (JavaVFrame)vf : vf.javaSender();
  }

  /** In this system, a JavaThread is the top-level factory for a
      RegisterMap, since the JavaThread implementation is already
      platform-specific and RegisterMap is also necessarily
      platform-specific. The updateMap argument indicates whether the
      register map needs to be updated, for example during stack
      traversal -- see frame.hpp. */
  public RegisterMap newRegisterMap(boolean updateMap){
        return access.newRegisterMap(this, updateMap);
  }

  /** This is only designed to be used by the debugging system.
      Returns a "best guess" of the topmost frame on the stack. This
      guess should be as "raw" as possible. For example, if the
      topmost frame is an interpreter frame (the return PC is in the
      interpreter) but is not a valid frame (i.e., the BCI has not yet
      been set up) this should still return the topmost frame and not
      the sender. Validity checks are done at higher levels. */
  public  Frame getCurrentFrameGuess(){
        return access.getCurrentFrameGuess(this, addr);
  }

  /** Also only intended for use by the debugging system. Provides the
      same effect of OSThread::print(); that is, prints a value which
      allows the user to intuitively understand which native OS thread
      maps to this Java thread. Does not print a newline or leading or
      trailing spaces. */
  public  void printThreadIDOn(PrintStream tty) {
        access.printThreadIDOn(addr,tty);
  }

  public void printThreadID() {
    printThreadIDOn(System.out);
  }

  public ThreadProxy getThreadProxy() {
    return access.getThreadProxy(addr);
  }

  //
  // Safepoint support
  //

  public JavaThreadState getThreadState() {
    int val = (int) threadStateField.getValue(addr);
    if (val == UNINITIALIZED) {
      return JavaThreadState.UNINITIALIZED;
    } else if (val == NEW) {
      return JavaThreadState.NEW;
    } else if (val == NEW_TRANS) {
      return JavaThreadState.NEW_TRANS;
    } else if (val == IN_NATIVE) {
      return JavaThreadState.IN_NATIVE;
    } else if (val == IN_NATIVE_TRANS) {
      return JavaThreadState.IN_NATIVE_TRANS;
    } else if (val == IN_VM) {
      return JavaThreadState.IN_VM;
    } else if (val == IN_VM_TRANS) {
      return JavaThreadState.IN_VM_TRANS;
    } else if (val == IN_JAVA) {
      return JavaThreadState.IN_JAVA;
    } else if (val == IN_JAVA_TRANS) {
      return JavaThreadState.IN_JAVA_TRANS;
    } else if (val == BLOCKED) {
      return JavaThreadState.BLOCKED;
    } else if (val == BLOCKED_TRANS) {
      return JavaThreadState.BLOCKED_TRANS;
    } else {
      throw new RuntimeException("Illegal thread state " + val);
    }
  }
  // FIXME: not yet implementable
  // public void setThreadState(JavaThreadState s);

  //
  // Miscellaneous operations
  //

  public OSThread getOSThread() {
    return (OSThread) VMObjectFactory.newObject(OSThread.class, osThreadField.getValue(addr));
  }

  public Address getStackBase() {
    return stackBaseField.getValue(addr);
  }

  public long getStackBaseValue() {
    return VM.getVM().getAddressValue(getStackBase());
  }

  public long getStackSize() {
    return stackSizeField.getValue(addr);
  }

  /** Gets the Java-side thread object for this JavaThread */
  public Oop getThreadObj() {
    Oop obj = null;
    try {
      obj = VM.getVM().getObjectHeap().newOop(threadObjField.getValue(addr));
    } catch (Exception e) {
      e.printStackTrace();
    }
    return obj;
  }

  /** Get the Java-side name of this thread */
  public String getThreadName() {
    Oop threadObj = getThreadObj();
    if (threadObj == null) {
        return "<null>";
    }
    return OopUtilities.threadOopGetName(threadObj);
  }

  //
  // Oop traversal
  //

  public void oopsDo(AddressVisitor oopVisitor) {
    super.oopsDo(oopVisitor);

    // FIXME: add in the rest of the routine from the VM

    // Traverse the execution stack
    for(StackFrameStream fst = new StackFrameStream(this); !fst.isDone(); fst.next()) {
      fst.getCurrent().oopsDo(oopVisitor, fst.getRegisterMap());
    }
  }

  public boolean isInStack(Address a) {
    if (Assert.ASSERTS_ENABLED) {
      Assert.that(VM.getVM().isDebugging(), "Not yet implemented for non-debugging system");
    }
    Address sp      = lastSPDbg();
    Address stackBase = getStackBase();
    // Be robust
    if (sp == null) return false;
    return stackBase.greaterThanOrEqual(a) && sp.lessThanOrEqual(a);
  }

  public boolean isLockOwned(Address a) {
    Address stackBase = getStackBase();
    Address stackLimit = stackBase.addOffsetTo(-getStackSize());

    return stackBase.greaterThanOrEqual(a) && stackLimit.lessThanOrEqual(a);

    // FIXME: should traverse MonitorArray/MonitorChunks as in VM
  }

  public Oop getCurrentParkBlocker() {
    Oop threadObj = getThreadObj();
    if (threadObj != null) {
      return OopUtilities.threadOopGetParkBlocker(threadObj);
    }
    return null;
  }

  public void printInfoOn(PrintStream tty) {

    tty.println("State: " + getThreadState().toString());
    // Attempt to figure out the addresses covered by Java frames.
    // NOTE: we should make this a method and let the Stackwalk panel use the result too.
    //
    sun.jvm.hotspot.runtime.Frame tmpFrame = getCurrentFrameGuess();
    if (tmpFrame != null ) {
      Address sp = tmpFrame.getSP();
      Address maxSP = sp;
      Address minSP = sp;
      RegisterMap tmpMap = newRegisterMap(false);
      while ((tmpFrame != null) && (!tmpFrame.isFirstFrame())) {
          tmpFrame = tmpFrame.sender(tmpMap);
          if (tmpFrame != null) {
            sp = tmpFrame.getSP();
            maxSP = AddressOps.max(maxSP, sp);
            minSP = AddressOps.min(minSP, sp);
          }
      }
      tty.println("Stack in use by Java: " + minSP + " .. " + maxSP);
    } else {
      tty.println("No Java frames present");
    }
    tty.println("Base of Stack: " + getBaseOfStackPointer());
    tty.println("Last_Java_SP: " + getLastJavaSP());
    tty.println("Last_Java_FP: " + getLastJavaFP());
    tty.println("Last_Java_PC: " + getLastJavaPC());
    // More stuff like saved_execption_pc, safepoint_state, ...
    access.printInfoOn(addr, tty);

  }

  ///////////////////////////////
  //                           //
  // FIXME: add more accessors //
  //                           //
  ///////////////////////////////

  //--------------------------------------------------------------------------------
  // Internals only below this point
  //

  private Frame cookLastFrame(Frame fr) {
    if (fr == null) {
      return null;
    }

    Address pc        = fr.getPC();

    if (Assert.ASSERTS_ENABLED) {
      if (pc == null) {
        Assert.that(VM.getVM().isDebugging(), "must have PC");
      }
    }
    return fr;
  }

  private Address lastSPDbg() {
    return access.getLastSP(addr);
  }

}