Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 2002-2007 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.

  *

  */

 class JavaThread;

 //

 // RegisterMap

 //

 // A companion structure used for stack traversal. The RegisterMap contains

 // misc. information needed in order to do correct stack traversal of stack

 // frames.  Hence, it must always be passed in as an argument to

 // frame::sender(RegisterMap*).

 //

 // In particular,

 //   1) It provides access to the thread for which the stack belongs.  The

 //      thread object is needed in order to get sender of a deoptimized frame.

 //

 //   2) It is used to pass information from a callee frame to its caller

 //      frame about how the frame should be traversed.  This is used to let

 //      the caller frame take care of calling oops-do of out-going

 //      arguments, when the callee frame is not instantiated yet.  This

 //      happens, e.g., when a compiled frame calls into

 //      resolve_virtual_call.  (Hence, it is critical that the same

 //      RegisterMap object is used for the entire stack walk.  Normally,

 //      this is hidden by using the StackFrameStream.)  This is used when

 //      doing follow_oops and oops_do.

 //

 //   3) The RegisterMap keeps track of the values of callee-saved registers

 //      from frame to frame (hence, the name).  For some stack traversal the

 //      values of the callee-saved registers does not matter, e.g., if you

 //      only need the static properies such as frame type, pc, and such.

 //      Updating of the RegisterMap can be turned off by instantiating the

 //      register map as: RegisterMap map(thread, false);

 class RegisterMap : public StackObj {

  public:

     typedef julong LocationValidType;

   enum {

     reg_count = ConcreteRegisterImpl::number_of_registers,

     location_valid_type_size = sizeof(LocationValidType)*8,

     location_valid_size = (reg_count+location_valid_type_size-1)/location_valid_type_size

   };

  private:

   intptr_t*    _location[reg_count];    // Location of registers (intptr_t* looks better than address in the debugger)

   LocationValidType _location_valid[location_valid_size];

   bool        _include_argument_oops;   // Should include argument_oop marked locations for compiler

   JavaThread* _thread;                  // Reference to current thread

   bool        _update_map;              // Tells if the register map need to be

                                         // updated when traversing the stack

 #ifdef ASSERT

   void check_location_valid();

 #else

   void check_location_valid() {}

 #endif

  public:

   debug_only(intptr_t* _update_for_id;) // Assert that RegisterMap is not updated twice for same frame

   RegisterMap(JavaThread *thread, bool update_map = true);

   RegisterMap(const RegisterMap* map);

   address location(VMReg reg) const {

     int index = reg->value() / location_valid_type_size;

     assert(0 <= reg->value() && reg->value() < reg_count, "range check");

     assert(0 <= index && index < location_valid_size, "range check");

     if (_location_valid[index] & ((LocationValidType)1 << (reg->value() % location_valid_type_size))) {

       return (address) _location[reg->value()];

     } else {

       return pd_location(reg);

     }

   }

   void set_location(VMReg reg, address loc) {

     int index = reg->value() / location_valid_type_size;

     assert(0 <= reg->value() && reg->value() < reg_count, "range check");

     assert(0 <= index && index < location_valid_size, "range check");

     assert(_update_map, "updating map that does not need updating");

     _location[reg->value()] = (intptr_t*) loc;

     _location_valid[index] |= ((LocationValidType)1 << (reg->value() % location_valid_type_size));

     check_location_valid();

   }

   // Called by an entry frame.

   void clear();

   bool include_argument_oops() const      { return _include_argument_oops; }

   void set_include_argument_oops(bool f)  { _include_argument_oops = f; }

   JavaThread *thread() const { return _thread; }

   bool update_map()    const { return _update_map; }

   void print_on(outputStream* st) const;

   void print() const;

   // the following contains the definition of pd_xxx methods

 # include "incls/_registerMap_pd.hpp.incl"

 };