1 /*

     2  * Copyright (c) 2016, 2018, 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  */

    24 

    25 #ifndef SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDBITS_INLINE_HPP

    26 #define SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDBITS_INLINE_HPP

    27 

    28 #include "jfr/utilities/jfrTypes.hpp"

    29 #include "runtime/atomic.hpp"

    30 #include "runtime/orderAccess.inline.hpp"

    31 #include "utilities/macros.hpp"

    32 

    33 #ifdef VM_LITTLE_ENDIAN

    34 static const int low_offset = 0;

    35 static const int leakp_offset = low_offset + 1;

    36 #else

    37 static const int low_offset = 7;

    38 static const int leakp_offset = low_offset - 1;

    39 #endif

    40 

    41 inline void set_bits(jbyte bits, jbyte* const dest) {

    42   assert(dest != NULL, "invariant");

    43   const jbyte current = OrderAccess::load_acquire(dest);

    44   if (bits != (current & bits)) {

    45     *dest |= bits;

    46   }

    47 }

    48 

    49 inline void set_mask(jbyte mask, jbyte* const dest) {

    50   assert(dest != NULL, "invariant");

    51   const jbyte current = OrderAccess::load_acquire(dest);

    52   if (mask != (current & mask)) {

    53     *dest &= mask;

    54   }

    55 }

    56 

    57 inline void set_bits_cas(jbyte bits, jbyte* const dest) {

    58   assert(dest != NULL, "invariant");

    59   do {

    60     const jbyte current = OrderAccess::load_acquire(dest);

    61     if (bits == (current & bits)) {

    62       return;

    63     }

    64     const jbyte new_value = current | bits;

    65     if (Atomic::cmpxchg(new_value, dest, current) == current) {

    66       return;

    67     }

    68   } while (true);

    69 }

    70 

    71 inline void clear_bits_cas(jbyte bits, jbyte* const dest) {

    72   assert(dest != NULL, "invariant");

    73   do {

    74     const jbyte current = OrderAccess::load_acquire(dest);

    75     if (bits != (current & bits)) {

    76       return;

    77     }

    78     const jbyte new_value = current ^ bits;

    79     if (Atomic::cmpxchg(new_value, dest, current) == current) {

    80       return;

    81     }

    82   } while (true);

    83 }

    84 

    85 inline void set_traceid_bits(jbyte bits, traceid* dest) {

    86   set_bits(bits, ((jbyte*)dest) + low_offset);

    87 }

    88 

    89 inline void set_traceid_bits_cas(jbyte bits, traceid* dest) {

    90   set_bits_cas(bits, ((jbyte*)dest) + low_offset);

    91 }

    92 

    93 inline void set_traceid_mask(jbyte mask, traceid* dest) {

    94   set_mask(mask, ((jbyte*)dest) + low_offset);

    95 }

    96 

    97 inline void set_leakp_traceid_bits(jbyte bits, traceid* dest) {

    98   set_bits(bits, ((jbyte*)dest) + leakp_offset);

    99 }

   100 

   101 inline void set_leakp_traceid_bits_cas(jbyte bits, traceid* dest) {

   102   set_bits_cas(bits, ((jbyte*)dest) + leakp_offset);

   103 }

   104 

   105 inline void set_leakp_traceid_mask(jbyte mask, traceid* dest) {

   106   set_mask(mask, ((jbyte*)dest) + leakp_offset);

   107 }

   108 

   109 #endif // SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDBITS_INLINE_HPP

   110