view src/share/vm/opto/multnode.hpp @ 3249:e1162778c1c8

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer. Reviewed-by: kvn, iveresov, never, tonyp, dholmes
author johnc
date Thu, 07 Apr 2011 09:53:20 -0700
parents f95d63e2154a
children 6f3fd5150b67
line wrap: on
line source

/*
 * Copyright (c) 1997, 2010, 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.
 *
 */

#ifndef SHARE_VM_OPTO_MULTNODE_HPP
#define SHARE_VM_OPTO_MULTNODE_HPP

#include "opto/node.hpp"

class Matcher;
class ProjNode;

//------------------------------MultiNode--------------------------------------
// This class defines a MultiNode, a Node which produces many values.  The
// values are wrapped up in a tuple Type, i.e. a TypeTuple.
class MultiNode : public Node {
public:
  MultiNode( uint required ) : Node(required) {
    init_class_id(Class_Multi);
  }
  virtual int Opcode() const;
  virtual const Type *bottom_type() const = 0;
  virtual bool       is_CFG() const { return true; }
  virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
  virtual bool depends_only_on_test() const { return false; }
  virtual const RegMask &out_RegMask() const;
  virtual Node *match( const ProjNode *proj, const Matcher *m );
  virtual uint ideal_reg() const { return NotAMachineReg; }
  ProjNode* proj_out(uint which_proj) const; // Get a named projection

};

//------------------------------ProjNode---------------------------------------
// This class defines a Projection node.  Projections project a single element
// out of a tuple (or Signature) type.  Only MultiNodes produce TypeTuple
// results.
class ProjNode : public Node {
protected:
  virtual uint hash() const;
  virtual uint cmp( const Node &n ) const;
  virtual uint size_of() const;
  void check_con() const;       // Called from constructor.

public:
  ProjNode( Node *src, uint con, bool io_use = false )
    : Node( src ), _con(con), _is_io_use(io_use)
  {
    init_class_id(Class_Proj);
    // Optimistic setting. Need additional checks in Node::is_dead_loop_safe().
    if (con != TypeFunc::Memory || src->is_Start())
      init_flags(Flag_is_dead_loop_safe);
    debug_only(check_con());
  }
  const uint _con;              // The field in the tuple we are projecting
  const bool _is_io_use;        // Used to distinguish between the projections
                                // used on the control and io paths from a macro node
  virtual int Opcode() const;
  virtual bool      is_CFG() const;
  virtual bool depends_only_on_test() const { return false; }
  virtual const Type *bottom_type() const;
  virtual const TypePtr *adr_type() const;
  virtual bool pinned() const;
  virtual const Type *Value( PhaseTransform *phase ) const;
  virtual uint ideal_reg() const;
  virtual const RegMask &out_RegMask() const;
#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const;
#endif
};

#endif // SHARE_VM_OPTO_MULTNODE_HPP