/*

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

package sun.jvm.hotspot.code;

import java.io.*;

import java.util.*;

import sun.jvm.hotspot.debugger.*;

import sun.jvm.hotspot.memory.*;

import sun.jvm.hotspot.oops.*;

import sun.jvm.hotspot.runtime.*;

import sun.jvm.hotspot.types.*;

import sun.jvm.hotspot.utilities.*;

public class NMethod extends CodeBlob {

  private static long          pcDescSize;

  private static CIntegerField zombieInstructionSizeField;

  private static sun.jvm.hotspot.types.OopField methodField;

  /** != InvocationEntryBci if this nmethod is an on-stack replacement method */

  private static CIntegerField entryBCIField;

  /** To support simple linked-list chaining of nmethods */

  private static AddressField  osrLinkField;

  private static AddressField  scavengeRootLinkField;

  private static JByteField    scavengeRootStateField;

  /** Offsets for different nmethod parts */

  private static CIntegerField exceptionOffsetField;

  private static CIntegerField deoptOffsetField;

  private static CIntegerField origPCOffsetField;

  private static CIntegerField stubOffsetField;

  private static CIntegerField scopesDataOffsetField;

  private static CIntegerField scopesPCsOffsetField;

  private static CIntegerField dependenciesOffsetField;

  private static CIntegerField handlerTableOffsetField;

  private static CIntegerField nulChkTableOffsetField;

  private static CIntegerField nmethodEndOffsetField;

  /** Offsets for entry points */

  /** Entry point with class check */

  private static AddressField  entryPointField;

  /** Entry point without class check */

  private static AddressField  verifiedEntryPointField;

  /** Entry point for on stack replacement */

  private static AddressField  osrEntryPointField;

  // FIXME: add access to flags (how?)

  /** NMethod Flushing lock (if non-zero, then the nmethod is not removed) */

  private static JIntField     lockCountField;

  /** not_entrant method removal. Each mark_sweep pass will update

      this mark to current sweep invocation count if it is seen on the

      stack.  An not_entrant method can be removed when there is no

      more activations, i.e., when the _stack_traversal_mark is less than

      current sweep traversal index. */

  private static CIntegerField stackTraversalMarkField;

  static {

    VM.registerVMInitializedObserver(new Observer() {

        public void update(Observable o, Object data) {

          initialize(VM.getVM().getTypeDataBase());

        }

      });

  }

  private static void initialize(TypeDataBase db) {

    Type type = db.lookupType("nmethod");

    zombieInstructionSizeField  = type.getCIntegerField("_zombie_instruction_size");

    methodField                 = type.getOopField("_method");

    entryBCIField               = type.getCIntegerField("_entry_bci");

    osrLinkField                = type.getAddressField("_osr_link");

    scavengeRootLinkField       = type.getAddressField("_scavenge_root_link");

    scavengeRootStateField      = type.getJByteField("_scavenge_root_state");

    exceptionOffsetField        = type.getCIntegerField("_exception_offset");

    deoptOffsetField            = type.getCIntegerField("_deoptimize_offset");

    origPCOffsetField           = type.getCIntegerField("_orig_pc_offset");

    stubOffsetField             = type.getCIntegerField("_stub_offset");

    scopesDataOffsetField       = type.getCIntegerField("_scopes_data_offset");

    scopesPCsOffsetField        = type.getCIntegerField("_scopes_pcs_offset");

    dependenciesOffsetField     = type.getCIntegerField("_dependencies_offset");

    handlerTableOffsetField     = type.getCIntegerField("_handler_table_offset");

    nulChkTableOffsetField      = type.getCIntegerField("_nul_chk_table_offset");

    nmethodEndOffsetField       = type.getCIntegerField("_nmethod_end_offset");

    entryPointField             = type.getAddressField("_entry_point");

    verifiedEntryPointField     = type.getAddressField("_verified_entry_point");

    osrEntryPointField          = type.getAddressField("_osr_entry_point");

    lockCountField              = type.getJIntField("_lock_count");

    stackTraversalMarkField     = type.getCIntegerField("_stack_traversal_mark");

    pcDescSize = db.lookupType("PcDesc").getSize();

  }

  public NMethod(Address addr) {

    super(addr);

  }

  // Accessors

  public Address getAddress() {

    return addr;

  }

  public Method getMethod() {

    return (Method) VM.getVM().getObjectHeap().newOop(methodField.getValue(addr));

  }

  // Type info

  public boolean isNMethod()      { return true;                    }

  public boolean isJavaMethod()   { return !getMethod().isNative(); }

  public boolean isNativeMethod() { return getMethod().isNative();  }

  public boolean isOSRMethod()    { return getEntryBCI() != VM.getVM().getInvocationEntryBCI(); }

  /** Boundaries for different parts */

  public Address constantsBegin()       { return instructionsBegin();                                }

  public Address constantsEnd()         { return getEntryPoint();                                    }

  public Address codeBegin()            { return getEntryPoint();                                    }

  public Address codeEnd()              { return headerBegin().addOffsetTo(getStubOffset());         }

  public Address exceptionBegin()       { return headerBegin().addOffsetTo(getExceptionOffset());    }

  public Address deoptBegin()           { return headerBegin().addOffsetTo(getDeoptOffset());        }

  public Address stubBegin()            { return headerBegin().addOffsetTo(getStubOffset());         }

  public Address scopesDataBegin()      { return headerBegin().addOffsetTo(getScopesDataOffset());   }

  public Address scopesDataEnd()        { return headerBegin().addOffsetTo(getScopesPCsOffset());    }

  public Address scopesPCsBegin()       { return headerBegin().addOffsetTo(getScopesPCsOffset());    }

  public Address scopesPCsEnd()         { return headerBegin().addOffsetTo(getDependenciesOffset()); }

  public Address dependenciesBegin()    { return headerBegin().addOffsetTo(getDependenciesOffset()); }

  public Address dependenciesEnd()      { return headerBegin().addOffsetTo(getHandlerTableOffset()); }

  public Address handlerTableBegin()    { return headerBegin().addOffsetTo(getHandlerTableOffset()); }

  public Address handlerTableEnd()      { return headerBegin().addOffsetTo(getNulChkTableOffset());  }

  public Address nulChkTableBegin()     { return headerBegin().addOffsetTo(getNulChkTableOffset());  }

  public Address nulChkTableEnd()       { return headerBegin().addOffsetTo(getNMethodEndOffset());   }

  public int constantsSize()            { return (int) constantsEnd()   .minus(constantsBegin());    }

  public int codeSize()                 { return (int) codeEnd()        .minus(codeBegin());         }

  public int stubSize()                 { return (int) stubEnd()        .minus(stubBegin());         }

  public int scopesDataSize()           { return (int) scopesDataEnd()  .minus(scopesDataBegin());   }

  public int scopesPCsSize()            { return (int) scopesPCsEnd()   .minus(scopesPCsBegin());    }

  public int dependenciesSize()         { return (int) dependenciesEnd().minus(dependenciesBegin()); }

  public int handlerTableSize()         { return (int) handlerTableEnd().minus(handlerTableBegin()); }

  public int nulChkTableSize()          { return (int) nulChkTableEnd() .minus(nulChkTableBegin());  }

  public int origPCOffset()             { return (int) origPCOffsetField.getValue(addr);             }

  public int totalSize() {

    return

      constantsSize()    +

      codeSize()         +

      stubSize()         +

      scopesDataSize()   +

      scopesPCsSize()    +

      dependenciesSize() +

      handlerTableSize() +

      nulChkTableSize();

  }

  public boolean constantsContains   (Address addr) { return constantsBegin()   .lessThanOrEqual(addr) && constantsEnd()   .greaterThan(addr); }

  public boolean codeContains        (Address addr) { return codeBegin()        .lessThanOrEqual(addr) && codeEnd()        .greaterThan(addr); }

  public boolean stubContains        (Address addr) { return stubBegin()        .lessThanOrEqual(addr) && stubEnd()        .greaterThan(addr); }

  public boolean scopesDataContains  (Address addr) { return scopesDataBegin()  .lessThanOrEqual(addr) && scopesDataEnd()  .greaterThan(addr); }

  public boolean scopesPCsContains   (Address addr) { return scopesPCsBegin()   .lessThanOrEqual(addr) && scopesPCsEnd()   .greaterThan(addr); }

  public boolean handlerTableContains(Address addr) { return handlerTableBegin().lessThanOrEqual(addr) && handlerTableEnd().greaterThan(addr); }

  public boolean nulChkTableContains (Address addr) { return nulChkTableBegin() .lessThanOrEqual(addr) && nulChkTableEnd() .greaterThan(addr); }

  /** Entry points */

  public Address getEntryPoint()         { return entryPointField.getValue(addr);         }

  public Address getVerifiedEntryPoint() { return verifiedEntryPointField.getValue(addr); }

  // FIXME: add interpreter_entry_point()

  // FIXME: add lazy_interpreter_entry_point() for C2

  // **********

  // * FIXME: * ADD ACCESS TO FLAGS!!!!

  // **********

  // public boolean isInUse();

  // public boolean isAlive();

  // public boolean isNotEntrant();

  // public boolean isZombie();

  // ********************************

  // * MAJOR FIXME: MAJOR HACK HERE *

  // ********************************

  public boolean isZombie() { return false; }

  // public boolean isUnloaded();

  // public boolean isYoung();

  // public boolean isOld();

  // public int     age();

  // public boolean isMarkedForDeoptimization();

  // public boolean isMarkedForUnloading();

  // public boolean isMarkedForReclamation();

  // public int     level();

  // public int     version();

  // FIXME: add mutators for above

  // FIXME: add exception cache access?

  /** On-stack replacement support */

  // FIXME: add mutators

  public int getOSREntryBCI() {

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(getEntryBCI() != VM.getVM().getInvocationEntryBCI(), "wrong kind of nmethod");

    }

    return getEntryBCI();

  }

  public NMethod getOSRLink() {

    return (NMethod) VMObjectFactory.newObject(NMethod.class, osrLinkField.getValue(addr));

  }

  public NMethod getScavengeRootLink() {

    return (NMethod) VMObjectFactory.newObject(NMethod.class, scavengeRootLinkField.getValue(addr));

  }

  public int getScavengeRootState() {

    return (int) scavengeRootStateField.getValue(addr);

  }

  /** Tells whether frames described by this nmethod can be

      deoptimized. Note: native wrappers cannot be deoptimized. */

  public boolean canBeDeoptimized() { return isJavaMethod(); }

  // FIXME: add inline cache support

  // FIXME: add flush()

  public boolean isLockedByVM() { return lockCountField.getValue(addr) > 0; }

  // FIXME: add mark_as_seen_on_stack

  // FIXME: add can_not_entrant_be_converted

  // FIXME: add GC support

  //  void follow_roots_or_mark_for_unloading(bool unloading_occurred, bool& marked_for_unloading);

  //  void follow_root_or_mark_for_unloading(oop* root, bool unloading_occurred, bool& marked_for_unloading);

  //  void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, void f(oop*));

  //  void adjust_pointers();

  /** Finds a PCDesc with real-pc equal to "pc" */

  public PCDesc getPCDescAt(Address pc) {

    // FIXME: consider adding cache like the one down in the VM

    for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {

      PCDesc pcDesc = new PCDesc(p);

      if (pcDesc.getRealPC(this).equals(pc)) {

        return pcDesc;

      }

    }

    return null;

  }

  /** ScopeDesc for an instruction */

  public ScopeDesc getScopeDescAt(Address pc) {

    PCDesc pd = getPCDescAt(pc);

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(pd != null, "scope must be present");

    }

    return new ScopeDesc(this, pd.getScopeDecodeOffset(), pd.getObjDecodeOffset(), pd.getReexecute());

  }

  /** This is only for use by the debugging system, and is only

      intended for use in the topmost frame, where we are not

      guaranteed to be at a PC for which we have a PCDesc. It finds

      the PCDesc with realPC closest to the current PC. */

  public PCDesc getPCDescNearDbg(Address pc) {

    PCDesc bestGuessPCDesc = null;

    long bestDistance = 0;

    for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {

      PCDesc pcDesc = new PCDesc(p);

      // In case pc is null

      long distance = -pcDesc.getRealPC(this).minus(pc);

      if ((bestGuessPCDesc == null) ||

          ((distance >= 0) && (distance < bestDistance))) {

        bestGuessPCDesc = pcDesc;

        bestDistance    = distance;

      }

    }

    return bestGuessPCDesc;

  }

  /** This is only for use by the debugging system, and is only

      intended for use in the topmost frame, where we are not

      guaranteed to be at a PC for which we have a PCDesc. It finds

      the ScopeDesc closest to the current PC. NOTE that this may

      return NULL for compiled methods which don't have any

      ScopeDescs! */

  public ScopeDesc getScopeDescNearDbg(Address pc) {

    PCDesc pd = getPCDescNearDbg(pc);

    if (pd == null) return null;

    return new ScopeDesc(this, pd.getScopeDecodeOffset(), pd.getObjDecodeOffset(), pd.getReexecute());

  }

  public Map/*<Address, PCDesc>*/ getSafepoints() {

    Map safepoints = new HashMap(); // Map<Address, PCDesc>

    sun.jvm.hotspot.debugger.Address p = null;

    for (p = scopesPCsBegin(); p.lessThan(scopesPCsEnd());

         p = p.addOffsetTo(pcDescSize)) {

       PCDesc pcDesc = new PCDesc(p);

       sun.jvm.hotspot.debugger.Address pc = pcDesc.getRealPC(this);

       safepoints.put(pc, pcDesc);

    }

    return safepoints;

  }

  // FIXME: add getPCOffsetForBCI()

  // FIXME: add embeddedOopAt()

  // FIXME: add isDependentOn()

  // FIXME: add isPatchableAt()

  /** Support for code generation. Only here for proof-of-concept. */

  public static int getEntryPointOffset()            { return (int) entryPointField.getOffset();            }

  public static int getVerifiedEntryPointOffset()    { return (int) verifiedEntryPointField.getOffset();    }

  public static int getOSREntryPointOffset()         { return (int) osrEntryPointField.getOffset();         }

  public static int getEntryBCIOffset()              { return (int) entryBCIField.getOffset();              }

  /** NOTE: renamed from "method_offset_in_bytes" */

  public static int getMethodOffset()                { return (int) methodField.getOffset();                }

  public void print() {

    printOn(System.out);

  }

  public String toString() {

    Method method = getMethod();

    return "NMethod for " +

            method.getMethodHolder().getName().asString() + "." +

            method.getName().asString() + method.getSignature().asString() + "==>n" +

            super.toString();

  }

  public String flagsToString() {

    // FIXME need access to flags...

    return "";

  }

  public String getName() {

    Method method = getMethod();

    return "NMethod for " +

           method.getMethodHolder().getName().asString() + "." +

           method.getName().asString() +

           method.getSignature().asString();

  }

  //--------------------------------------------------------------------------------

  // Internals only below this point

  //

  private int getEntryBCI()           { return (int) entryBCIField          .getValue(addr); }

  private int getExceptionOffset()    { return (int) exceptionOffsetField   .getValue(addr); }

  private int getDeoptOffset()        { return (int) deoptOffsetField       .getValue(addr); }

  private int getStubOffset()         { return (int) stubOffsetField        .getValue(addr); }

  private int getScopesDataOffset()   { return (int) scopesDataOffsetField  .getValue(addr); }

  private int getScopesPCsOffset()    { return (int) scopesPCsOffsetField   .getValue(addr); }

  private int getDependenciesOffset() { return (int) dependenciesOffsetField.getValue(addr); }

  private int getHandlerTableOffset() { return (int) handlerTableOffsetField.getValue(addr); }

  private int getNulChkTableOffset()  { return (int) nulChkTableOffsetField .getValue(addr); }

  private int getNMethodEndOffset()   { return (int) nmethodEndOffsetField  .getValue(addr); }

}