/*

 * Copyright 2000-2005 Sun Microsystems, Inc.  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 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.compiler;

import java.util.*;

import sun.jvm.hotspot.code.*;

import sun.jvm.hotspot.debugger.*;

import sun.jvm.hotspot.runtime.*;

import sun.jvm.hotspot.types.*;

import sun.jvm.hotspot.utilities.*;

public class OopMapSet extends VMObject {

  private static final boolean DEBUG = System.getProperty("sun.jvm.hotspot.compiler.OopMapSet.DEBUG") != null;

  private static CIntegerField omCountField;

  private static CIntegerField omSizeField;

  private static AddressField  omDataField;

  private static int REG_COUNT;

  private static int SAVED_ON_ENTRY_REG_COUNT;

  private static int C_SAVED_ON_ENTRY_REG_COUNT;

  private static class MyVisitor implements OopMapVisitor {

    private AddressVisitor addressVisitor;

    public MyVisitor(AddressVisitor oopVisitor) {

      setAddressVisitor(oopVisitor);

    }

    public void setAddressVisitor(AddressVisitor addressVisitor) {

      this.addressVisitor = addressVisitor;

    }

    public void visitOopLocation(Address oopAddr) {

      addressVisitor.visitAddress(oopAddr);

    }

    public void visitDerivedOopLocation(Address baseOopAddr, Address derivedOopAddr) {

      if (VM.getVM().isClientCompiler()) {

        Assert.that(false, "should not reach here");

      } else if (VM.getVM().isServerCompiler() &&

                 VM.getVM().useDerivedPointerTable()) {

        Assert.that(false, "FIXME: add derived pointer table");

      }

    }

    public void visitValueLocation(Address valueAddr) {

    }

    }

  }

  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("OopMapSet");

    omCountField  = type.getCIntegerField("_om_count");

    omSizeField   = type.getCIntegerField("_om_size");

    omDataField   = type.getAddressField("_om_data");

    if (!VM.getVM().isCore()) {

      REG_COUNT = db.lookupIntConstant("REG_COUNT").intValue();

      if (VM.getVM().isServerCompiler()) {

        SAVED_ON_ENTRY_REG_COUNT = (int) db.lookupIntConstant("SAVED_ON_ENTRY_REG_COUNT").intValue();

        C_SAVED_ON_ENTRY_REG_COUNT = (int) db.lookupIntConstant("C_SAVED_ON_ENTRY_REG_COUNT").intValue();

      }

    }

  }

  public OopMapSet(Address addr) {

    super(addr);

  }

  /** Returns the number of OopMaps in this OopMapSet */

  public long getSize() {

    return omCountField.getValue(addr);

  }

  /** returns the OopMap at a given index */

  public OopMap getMapAt(int index) {

    if (Assert.ASSERTS_ENABLED) {

      Assert.that((index >= 0) && (index <= getSize()),"bad index");

    }

    Address omDataAddr = omDataField.getValue(addr);

    Address oopMapAddr = omDataAddr.getAddressAt(index * VM.getVM().getAddressSize());

    if (oopMapAddr == null) {

      return null;

    }

    return new OopMap(oopMapAddr);

  }

  public OopMap findMapAtOffset(long pcOffset, boolean debugging) {

    int i;

    int len = (int) getSize();

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(len > 0, "must have pointer maps");

    }

    // Scan through oopmaps. Stop when current offset is either equal or greater

    // than the one we are looking for.

    for (i = 0; i < len; i++) {

      if (getMapAt(i).getOffset() >= pcOffset) {

        break;

      }

    }

    if (!debugging) {

      if (Assert.ASSERTS_ENABLED) {

        Assert.that(i < len, "oopmap not found for pcOffset = " + pcOffset + "; len = " + len);

        Assert.that(getMapAt(i).getOffset() == pcOffset, "oopmap not found");

      }

    } else {

      if (i == len) {

        if (DEBUG) {

          System.out.println("can't find oopmap at " + pcOffset);

          System.out.print("Oopmap offsets are [ ");

          for (i = 0; i < len; i++) {

            System.out.print(getMapAt(i).getOffset());

          }

          System.out.println("]");

        }

        i = len - 1;

        return getMapAt(i);

      }

    }

    OopMap m = getMapAt(i);

    return m;

  }

  /** Visitation -- iterates through the frame for a compiled method.

      This is a very generic mechanism that requires the Address to be

      dereferenced by the callee. Other, more specialized, visitation

      mechanisms are given below. */

  public static void oopsDo(Frame fr, CodeBlob cb, RegisterMap regMap, AddressVisitor oopVisitor, boolean debugging) {

    allDo(fr, cb, regMap, new MyVisitor(oopVisitor), debugging);

  }

  /** Note that there are 4 required AddressVisitors: one for oops,

      one for derived oops, one for values, and one for dead values */

  public static void allDo(Frame fr, CodeBlob cb, RegisterMap regMap, OopMapVisitor visitor, boolean debugging) {

    if (Assert.ASSERTS_ENABLED) {

      CodeBlob tmpCB = VM.getVM().getCodeCache().findBlob(fr.getPC());

      Assert.that(tmpCB != null && cb.equals(tmpCB), "wrong codeblob passed in");

    }

    OopMapSet maps = cb.getOopMaps();

    OopMap map = cb.getOopMapForReturnAddress(fr.getPC(), debugging);

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(map != null, "no ptr map found");

    }

    // handle derived pointers first (otherwise base pointer may be

    // changed before derived pointer offset has been collected)

    OopMapValue omv;

    {

      for (OopMapStream oms = new OopMapStream(map, OopMapValue.OopTypes.DERIVED_OOP_VALUE); !oms.isDone(); oms.next()) {

        if (VM.getVM().isClientCompiler()) {

          Assert.that(false, "should not reach here");

        }

        omv = oms.getCurrent();

        Address loc = fr.oopMapRegToLocation(omv.getReg(), regMap);

        if (loc != null) {

          Address baseLoc    = fr.oopMapRegToLocation(omv.getContentReg(), regMap);

          Address derivedLoc = loc;

          visitor.visitDerivedOopLocation(baseLoc, derivedLoc);

        }

      }

    }

    OopMapValue.OopTypes[] values = new OopMapValue.OopTypes[] {

    };

    {

      for (OopMapStream oms = new OopMapStream(map, values); !oms.isDone(); oms.next()) {

        omv = oms.getCurrent();

        Address loc = fr.oopMapRegToLocation(omv.getReg(), regMap);

        if (loc != null) {

          if (omv.getType() == OopMapValue.OopTypes.OOP_VALUE) {

            // This assert commented out because this will be useful

            // to detect in the debugging system

            // assert(Universe::is_heap_or_null(*loc), "found non oop pointer");

            visitor.visitOopLocation(loc);

          } else if (omv.getType() == OopMapValue.OopTypes.VALUE_VALUE) {

            visitor.visitValueLocation(loc);

          }

        }

      }

    }

  }

  /** Update callee-saved register info for the following frame.

      Should only be called in non-core builds. */

  public static void updateRegisterMap(Frame fr, CodeBlob cb, RegisterMap regMap, boolean debugging) {

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(!VM.getVM().isCore(), "non-core builds only");

    }

    if (!VM.getVM().isDebugging()) {

      if (Assert.ASSERTS_ENABLED) {

        OopMapSet maps = cb.getOopMaps();

        Assert.that((maps != null) && (maps.getSize() > 0), "found null or empty OopMapSet for CodeBlob");

      }

    } else {

      // Hack for some topmost frames that have been found with empty

      // OopMapSets. (Actually have not seen the null case, but don't

      // want to take any chances.) See HSDB.showThreadStackMemory().

      OopMapSet maps = cb.getOopMaps();

      if ((maps == null) || (maps.getSize() == 0)) {

        return;

      }

    }

    // Check if caller must update oop argument

    regMap.setIncludeArgumentOops(cb.callerMustGCArguments(regMap.getThread()));

    int nofCallee = 0;

    Address[] locs = new Address[2 * REG_COUNT + 1];

    VMReg  [] regs = new VMReg  [2 * REG_COUNT + 1];

    // ("+1" because REG_COUNT might be zero)

    // Scan through oopmap and find location of all callee-saved registers

    // (we do not do update in place, since info could be overwritten)

    OopMap map  = cb.getOopMapForReturnAddress(fr.getPC(), debugging);

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(map != null, "no ptr map found");

    }

    OopMapValue omv = null;

    for(OopMapStream oms = new OopMapStream(map, OopMapValue.OopTypes.CALLEE_SAVED_VALUE); !oms.isDone(); oms.next()) {

      omv = oms.getCurrent();

      if (Assert.ASSERTS_ENABLED) {

        Assert.that(nofCallee < 2 * REG_COUNT, "overflow");

      }

      regs[nofCallee] = omv.getContentReg();

      locs[nofCallee] = fr.oopMapRegToLocation(omv.getReg(), regMap);

      nofCallee++;

    }

    // Check that runtime stubs save all callee-saved registers

    // After adapter frames were deleted C2 doesn't use callee save registers at present

    if (Assert.ASSERTS_ENABLED) {

      if (VM.getVM().isServerCompiler()) {

        Assert.that(!cb.isRuntimeStub() ||

                    (nofCallee >= SAVED_ON_ENTRY_REG_COUNT || nofCallee >= C_SAVED_ON_ENTRY_REG_COUNT),

                    "must save all");

      }

    }

    // Copy found callee-saved register to reg_map

    for (int i = 0; i < nofCallee; i++) {

      regMap.setLocation(regs[i], locs[i]);

    }

  }

}