src/cpu/sparc/vm/bytes_sparc.hpp

Thu, 07 Apr 2011 09:53:20 -0700

author
johnc
date
Thu, 07 Apr 2011 09:53:20 -0700
changeset 2781
e1162778c1c8
parent 2314
f95d63e2154a
child 6876
710a3c8b516e
permissions
-rw-r--r--

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

     1 /*
     2  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #ifndef CPU_SPARC_VM_BYTES_SPARC_HPP
    26 #define CPU_SPARC_VM_BYTES_SPARC_HPP
    28 #include "memory/allocation.hpp"
    30 class Bytes: AllStatic {
    31  public:
    32   // Efficient reading and writing of unaligned unsigned data in platform-specific byte ordering
    33   // Sparc needs to check for alignment.
    35   // can I count on address always being a pointer to an unsigned char? Yes
    37   // Returns true, if the byte ordering used by Java is different from the nativ byte ordering
    38   // of the underlying machine. For example, true for Intel x86, False, for Solaris on Sparc.
    39   static inline bool is_Java_byte_ordering_different() { return false; }
    41   // Thus, a swap between native and Java ordering is always a no-op:
    42   static inline u2   swap_u2(u2 x)  { return x; }
    43   static inline u4   swap_u4(u4 x)  { return x; }
    44   static inline u8   swap_u8(u8 x)  { return x; }
    46   static inline u2   get_native_u2(address p){
    47     return (intptr_t(p) & 1) == 0
    48              ?   *(u2*)p
    49              :   ( u2(p[0]) << 8 )
    50                | ( u2(p[1])      );
    51   }
    53   static inline u4   get_native_u4(address p) {
    54     switch (intptr_t(p) & 3) {
    55      case 0:  return *(u4*)p;
    57      case 2:  return (  u4( ((u2*)p)[0] ) << 16  )
    58                    | (  u4( ((u2*)p)[1] )                  );
    60     default:  return ( u4(p[0]) << 24 )
    61                    | ( u4(p[1]) << 16 )
    62                    | ( u4(p[2]) <<  8 )
    63                    |   u4(p[3]);
    64     }
    65   }
    67   static inline u8   get_native_u8(address p) {
    68     switch (intptr_t(p) & 7) {
    69       case 0:  return *(u8*)p;
    71       case 4:  return (  u8( ((u4*)p)[0] ) << 32  )
    72                     | (  u8( ((u4*)p)[1] )        );
    74       case 2:  return (  u8( ((u2*)p)[0] ) << 48  )
    75                     | (  u8( ((u2*)p)[1] ) << 32  )
    76                     | (  u8( ((u2*)p)[2] ) << 16  )
    77                     | (  u8( ((u2*)p)[3] )        );
    79      default:  return ( u8(p[0]) << 56 )
    80                     | ( u8(p[1]) << 48 )
    81                     | ( u8(p[2]) << 40 )
    82                     | ( u8(p[3]) << 32 )
    83                     | ( u8(p[4]) << 24 )
    84                     | ( u8(p[5]) << 16 )
    85                     | ( u8(p[6]) <<  8 )
    86                     |   u8(p[7]);
    87     }
    88   }
    92   static inline void put_native_u2(address p, u2 x)   {
    93     if ( (intptr_t(p) & 1) == 0 )  *(u2*)p = x;
    94     else {
    95       p[0] = x >> 8;
    96       p[1] = x;
    97     }
    98   }
   100   static inline void put_native_u4(address p, u4 x) {
   101     switch ( intptr_t(p) & 3 ) {
   102     case 0:  *(u4*)p = x;
   103               break;
   105     case 2:  ((u2*)p)[0] = x >> 16;
   106              ((u2*)p)[1] = x;
   107              break;
   109     default: ((u1*)p)[0] = x >> 24;
   110              ((u1*)p)[1] = x >> 16;
   111              ((u1*)p)[2] = x >>  8;
   112              ((u1*)p)[3] = x;
   113              break;
   114     }
   115   }
   117   static inline void put_native_u8(address p, u8 x) {
   118     switch ( intptr_t(p) & 7 ) {
   119     case 0:  *(u8*)p = x;
   120              break;
   122     case 4:  ((u4*)p)[0] = x >> 32;
   123              ((u4*)p)[1] = x;
   124              break;
   126     case 2:  ((u2*)p)[0] = x >> 48;
   127              ((u2*)p)[1] = x >> 32;
   128              ((u2*)p)[2] = x >> 16;
   129              ((u2*)p)[3] = x;
   130              break;
   132     default: ((u1*)p)[0] = x >> 56;
   133              ((u1*)p)[1] = x >> 48;
   134              ((u1*)p)[2] = x >> 40;
   135              ((u1*)p)[3] = x >> 32;
   136              ((u1*)p)[4] = x >> 24;
   137              ((u1*)p)[5] = x >> 16;
   138              ((u1*)p)[6] = x >>  8;
   139              ((u1*)p)[7] = x;
   140     }
   141   }
   144   // Efficient reading and writing of unaligned unsigned data in Java byte ordering (i.e. big-endian ordering)
   145   // (no byte-order reversal is needed since SPARC CPUs are big-endian oriented)
   146   static inline u2   get_Java_u2(address p) { return get_native_u2(p); }
   147   static inline u4   get_Java_u4(address p) { return get_native_u4(p); }
   148   static inline u8   get_Java_u8(address p) { return get_native_u8(p); }
   150   static inline void put_Java_u2(address p, u2 x)     { put_native_u2(p, x); }
   151   static inline void put_Java_u4(address p, u4 x)     { put_native_u4(p, x); }
   152   static inline void put_Java_u8(address p, u8 x)     { put_native_u8(p, x); }
   153 };
   155 //Reconciliation History
   156 // 1.7 98/02/24 10:18:41 bytes_i486.hpp
   157 // 1.10 98/04/08 18:47:57 bytes_i486.hpp
   158 // 1.13 98/07/15 17:10:03 bytes_i486.hpp
   159 // 1.14 98/08/13 10:38:23 bytes_i486.hpp
   160 // 1.15 98/10/05 16:30:21 bytes_i486.hpp
   161 // 1.17 99/06/22 16:37:35 bytes_i486.hpp
   162 //End
   164 #endif // CPU_SPARC_VM_BYTES_SPARC_HPP

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