/*
 * Copyright (c) 2003, 2019, 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.debugger.linux.amd64;

import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.debugger.amd64.*;
import sun.jvm.hotspot.debugger.linux.*;
import sun.jvm.hotspot.debugger.cdbg.*;
import sun.jvm.hotspot.debugger.cdbg.basic.*;

final public class LinuxAMD64CFrame extends BasicCFrame {
   public LinuxAMD64CFrame(LinuxDebugger dbg, Address cfa, Address rip, DwarfParser dwarf) {
      super(dbg.getCDebugger());
      this.cfa = cfa;
      this.rip = rip;
      this.dbg = dbg;
      this.dwarf = dwarf;
   }

   // override base class impl to avoid ELF parsing
   public ClosestSymbol closestSymbolToPC() {
      // try native lookup in debugger.
      return dbg.lookup(dbg.getAddressValue(pc()));
   }

   public Address pc() {
      return rip;
   }

   public Address localVariableBase() {
      return cfa;
   }

   private boolean isValidFrame(Address nextCFA, ThreadProxy thread) {
     return (nextCFA != null) &&
             !nextCFA.addOffsetTo(1 * 1024 * 1024 * 1024).lessThan(cfa) && // FIXME: assume to 1GB diff
             !nextCFA.lessThan(thread.getContext().getRegisterAsAddress(AMD64ThreadContext.RSP));
   }

   private CFrame javaSender(ThreadProxy thread) {
      Address nextCFA;
      Address nextPC;
      try { // FIXME: cannot read RBP from CFA in some case
        nextCFA = cfa.getAddressAt(0);
        // FIXME: assume to 1GB diff of stack
        if (!isValidFrame(nextCFA, thread)) {
          return null;
        }

        nextPC  = nextCFA.getAddressAt( 1 * ADDRESS_SIZE);
        if (nextPC == null) {
          return null;
        }
      } catch (UnmappedAddressException | UnalignedAddressException e) {
        return null;
      }

      DwarfParser nextDwarf = null;
      long libptr = dbg.findLibPtrByAddress(nextPC);
      if (libptr != 0L) { // Native frame
        try {
          nextDwarf = new DwarfParser(libptr);
        } catch (DebuggerException e) {
          return new LinuxAMD64CFrame(dbg, nextCFA, nextPC, null);
        }
        nextDwarf.processDwarf(nextPC);
        nextCFA = nextCFA.addOffsetTo(- nextDwarf.getBasePointerOffsetFromCFA());
        if (!isValidFrame(nextCFA, thread)) {
          return null;
        }
      }

      return new LinuxAMD64CFrame(dbg, nextCFA, nextPC, nextDwarf);
   }

   public CFrame sender(ThreadProxy thread) {
      if (dwarf == null) { // Java frame
        return javaSender(thread);
      }

      Address nextPC;
      Address nextCFA;
      try { // FIXME: cannot read RBP from CFA in some case
        nextPC  = cfa.getAddressAt(dwarf.getReturnAddressOffsetFromCFA());
        if (nextPC == null) {
          return null;
        }

        nextCFA = cfa.getAddressAt(dwarf.getBasePointerOffsetFromCFA());
        if (!isValidFrame(nextCFA, thread)) {
          return null;
        }
      } catch (UnmappedAddressException | UnalignedAddressException e) {
        return null;
      }

      DwarfParser nextDwarf = dwarf;
      if (!dwarf.isIn(nextPC)) {
        long libptr = dbg.findLibPtrByAddress(nextPC);
        if (libptr == 0L) {
          // Next frame might be Java frame
          return new LinuxAMD64CFrame(dbg, nextCFA, nextPC, null);
        }
        try {
          nextDwarf = new DwarfParser(libptr);
        } catch (DebuggerException e) {
          nextCFA = cfa.getAddressAt(0);
          return isValidFrame(nextCFA, thread) ? new LinuxAMD64CFrame(dbg, nextCFA, nextPC, null)
                                               : null;
        }
      }

      nextDwarf.processDwarf(nextPC);

      int nextCFAReg = nextDwarf.getCFARegister();
      if (!dwarf.isBPOffsetAvailable() &&
          (nextCFAReg == AMD64ThreadContext.RBP) &&
          (nextCFAReg != dwarf.getCFARegister())) {
        nextCFA = thread.getContext()
                        .getRegisterAsAddress(AMD64ThreadContext.RBP);
        if (!isValidFrame(nextCFA, thread)) {
          return null;
        }
      }

      nextCFA = nextCFA.addOffsetTo(- nextDwarf.getBasePointerOffsetFromCFA());
      return isValidFrame(nextCFA, thread) ? new LinuxAMD64CFrame(dbg, nextCFA, nextPC, nextDwarf)
                                           : null;
   }

   // package/class internals only
   private static final int ADDRESS_SIZE = 8;
   private Address rip;
   private Address cfa;
   private LinuxDebugger dbg;
   private DwarfParser dwarf;
}