view src/share/vm/c1/c1_ValueType.cpp @ 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 1d7922586cf6
line wrap: on
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/*
 * Copyright (c) 1999, 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.
 *
 */

#include "precompiled.hpp"
#include "c1/c1_ValueType.hpp"
#include "ci/ciArray.hpp"
#include "ci/ciInstance.hpp"
#include "ci/ciNullObject.hpp"


// predefined types
VoidType*       voidType     = NULL;
IntType*        intType      = NULL;
LongType*       longType     = NULL;
FloatType*      floatType    = NULL;
DoubleType*     doubleType   = NULL;
ObjectType*     objectType   = NULL;
ArrayType*      arrayType    = NULL;
InstanceType*   instanceType = NULL;
ClassType*      classType    = NULL;
AddressType*    addressType  = NULL;
IllegalType*    illegalType  = NULL;


// predefined constants
IntConstant*    intZero      = NULL;
IntConstant*    intOne       = NULL;
ObjectConstant* objectNull   = NULL;


void ValueType::initialize(Arena* arena) {
  // Note: Must initialize all types for each compilation
  //       as they are allocated within a ResourceMark!

  // types
  voidType     = new (arena) VoidType();
  intType      = new (arena) IntType();
  longType     = new (arena) LongType();
  floatType    = new (arena) FloatType();
  doubleType   = new (arena) DoubleType();
  objectType   = new (arena) ObjectType();
  arrayType    = new (arena) ArrayType();
  instanceType = new (arena) InstanceType();
  classType    = new (arena) ClassType();
  addressType  = new (arena) AddressType();
  illegalType  = new (arena) IllegalType();

  intZero     = new (arena) IntConstant(0);
  intOne      = new (arena) IntConstant(1);
  objectNull  = new (arena) ObjectConstant(ciNullObject::make());
};


ValueType* ValueType::meet(ValueType* y) const {
  // incomplete & conservative solution for now - fix this!
  assert(tag() == y->tag(), "types must match");
  return base();
}


ValueType* ValueType::join(ValueType* y) const {
  Unimplemented();
  return NULL;
}



jobject ObjectType::encoding() const {
  assert(is_constant(), "must be");
  return constant_value()->constant_encoding();
}

bool ObjectType::is_loaded() const {
  assert(is_constant(), "must be");
  return constant_value()->is_loaded();
}

ciObject* ObjectConstant::constant_value() const                   { return _value; }
ciObject* ArrayConstant::constant_value() const                    { return _value; }
ciObject* InstanceConstant::constant_value() const                 { return _value; }
ciObject* ClassConstant::constant_value() const                    { return _value; }


ValueType* as_ValueType(BasicType type) {
  switch (type) {
    case T_VOID   : return voidType;
    case T_BYTE   : // fall through
    case T_CHAR   : // fall through
    case T_SHORT  : // fall through
    case T_BOOLEAN: // fall through
    case T_INT    : return intType;
    case T_LONG   : return longType;
    case T_FLOAT  : return floatType;
    case T_DOUBLE : return doubleType;
    case T_ARRAY  : return arrayType;
    case T_OBJECT : return objectType;
    case T_ADDRESS: return addressType;
    case T_ILLEGAL: return illegalType;
  }
  ShouldNotReachHere();
  return illegalType;
}


ValueType* as_ValueType(ciConstant value) {
  switch (value.basic_type()) {
    case T_BYTE   : // fall through
    case T_CHAR   : // fall through
    case T_SHORT  : // fall through
    case T_BOOLEAN: // fall through
    case T_INT    : return new IntConstant   (value.as_int   ());
    case T_LONG   : return new LongConstant  (value.as_long  ());
    case T_FLOAT  : return new FloatConstant (value.as_float ());
    case T_DOUBLE : return new DoubleConstant(value.as_double());
    case T_ARRAY  : // fall through (ciConstant doesn't have an array accessor)
    case T_OBJECT : return new ObjectConstant(value.as_object());
  }
  ShouldNotReachHere();
  return illegalType;
}


BasicType as_BasicType(ValueType* type) {
  switch (type->tag()) {
    case voidTag:    return T_VOID;
    case intTag:     return T_INT;
    case longTag:    return T_LONG;
    case floatTag:   return T_FLOAT;
    case doubleTag:  return T_DOUBLE;
    case objectTag:  return T_OBJECT;
    case addressTag: return T_ADDRESS;
    case illegalTag: return T_ILLEGAL;
  }
  ShouldNotReachHere();
  return T_ILLEGAL;
}