1 /*

     2  * Copyright (c) 2019, 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 #include "precompiled.hpp"

    25 #include "classfile/systemDictionary.hpp"

    26 #include "memory/resourceArea.hpp"

    27 #include "memory/universe.hpp"

    28 #include "oops/oop.inline.hpp"

    29 #include "runtime/atomic.hpp"

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

    31 #include "runtime/orderAccess.hpp"

    32 #include "runtime/os.hpp"

    33 #include "runtime/synchronizer.hpp"

    34 #include "runtime/semaphore.inline.hpp"

    35 #include "threadHelper.inline.hpp"

    36 #include "unittest.hpp"

    37 #include "utilities/globalDefinitions.hpp"

    38 #include "utilities/ostream.hpp"

    39 

    40 // The test doesn't work for PRODUCT because it needs WizardMode

    41 #ifndef PRODUCT

    42 static bool test_pattern(stringStream* st, const char* pattern) {

    43   return (strstr(st->as_string(), pattern) != NULL);

    44 }

    45 

    46 static void assert_test_pattern(Handle object, const char* pattern) {

    47   stringStream st;

    48   object->print_on(&st);

    49   ASSERT_TRUE(test_pattern(&st, pattern)) << pattern << " not in " << st.as_string();

    50 }

    51 

    52 static void assert_not_test_pattern(Handle object, const char* pattern) {

    53   stringStream st;

    54   object->print_on(&st);

    55   ASSERT_FALSE(test_pattern(&st, pattern)) << pattern << " found in " << st.as_string();

    56 }

    57 

    58 class LockerThread : public JavaTestThread {

    59   oop _obj;

    60   public:

    61   LockerThread(Semaphore* post, oop obj) : JavaTestThread(post), _obj(obj) {}

    62   virtual ~LockerThread() {}

    63 

    64   void main_run() {

    65     Thread* THREAD = Thread::current();

    66     HandleMark hm(THREAD);

    67     Handle h_obj(THREAD, _obj);

    68     ResourceMark rm(THREAD);

    69 

    70     // Wait gets the lock inflated.

    71     // The object will stay locked for the context of 'ol' so the lock will

    72     // still be inflated after the notify_all() call. Deflation can't happen

    73     // while an ObjectMonitor is "busy" and being locked is the most "busy"

    74     // state we have...

    75     ObjectLocker ol(h_obj, THREAD);

    76     ol.notify_all(THREAD);

    77     assert_test_pattern(h_obj, "monitor");

    78   }

    79 };

    80 

    81 

    82 TEST_VM(markWord, printing) {

    83   JavaThread* THREAD = JavaThread::current();

    84   ThreadInVMfromNative invm(THREAD);

    85   ResourceMark rm(THREAD);

    86 

    87   oop obj = SystemDictionary::Byte_klass()->allocate_instance(THREAD);

    88 

    89   FlagSetting fs(WizardMode, true);

    90   FlagSetting bf(UseBiasedLocking, true);

    91 

    92   HandleMark hm(THREAD);

    93   Handle h_obj(THREAD, obj);

    94 

    95   // Biased locking is initially enabled for this java.lang.Byte object.

    96   assert_test_pattern(h_obj, "is_biased");

    97 

    98   // Lock using biased locking.

    99   BasicObjectLock lock;

   100   lock.set_obj(obj);

   101   markWord prototype_header = obj->klass()->prototype_header();

   102   markWord mark = obj->mark();

   103   markWord biased_mark = markWord::encode((JavaThread*) THREAD, mark.age(), prototype_header.bias_epoch());

   104   obj->set_mark(biased_mark);

   105   // Look for the biased_locker in markWord, not prototype_header.

   106 #ifdef _LP64

   107   assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x0000000000000000");

   108 #else

   109   assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x00000000");

   110 #endif

   111 

   112   // Same thread tries to lock it again.

   113   {

   114     ObjectLocker ol(h_obj, THREAD);

   115     assert_test_pattern(h_obj, "locked");

   116   }

   117 

   118   // This is no longer biased, because ObjectLocker revokes the bias.

   119   assert_test_pattern(h_obj, "is_neutral no_hash");

   120 

   121   // Wait gets the lock inflated.

   122   {

   123     ObjectLocker ol(h_obj, THREAD);

   124 

   125     Semaphore done(0);

   126     LockerThread* st;

   127     st = new LockerThread(&done, h_obj());

   128     st->doit();

   129 

   130     ol.wait(THREAD);

   131     assert_test_pattern(h_obj, "monitor");

   132     done.wait_with_safepoint_check(THREAD);  // wait till the thread is done.

   133   }

   134 

   135   // Make the object older. Not all GCs use this field.

   136   Universe::heap()->collect(GCCause::_java_lang_system_gc);

   137   if (UseParallelGC) {

   138     assert_test_pattern(h_obj, "is_neutral no_hash age 1");

   139   }

   140 

   141   // Hash the object then print it.

   142   intx hash = h_obj->identity_hash();

   143   assert_test_pattern(h_obj, "is_neutral hash=0x");

   144 }

   145 #endif // PRODUCT