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test/hotspot/jtreg/vmTestbase/nsk/jdwp/ThreadReference/ForceEarlyReturn/forceEarlyReturn002/libforceEarlyReturn002a.cpp

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   1 /*
   2  * Copyright (c) 2007, 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 #include "jni.h"
  25 
  26 extern "C" {
  27 
  28 
  29 int always_true = 1;
  30 
  31 JNIEXPORT jint JNICALL
  32 Java_nsk_jdwp_ThreadReference_ForceEarlyReturn_forceEarlyReturn002_forceEarlyReturn002a_nativeMethod(JNIEnv *env, jobject classObject, jobject object)
  33 {
  34     int dummy_counter = 0;
  35     // notify another thread that thread in native method
  36     jclass klass = env->GetObjectClass(object);
  37     jfieldID field = env->GetFieldID(klass, "threadInNative", "Z");
  38     env->SetBooleanField(object, field, 1);
  39 
  40     // execute infinite loop to be sure that thread in native method
  41     while (always_true)
  42     {
  43         // Need some dummy code so the optimizer does not remove this loop.
  44         dummy_counter = dummy_counter < 1000 ? 0 : dummy_counter + 1;
  45     }
  46     // The optimizer can be surprisingly clever.
  47     // Use dummy_counter so it can never be optimized out.
  48     // This statement will always return 0.
  49     return dummy_counter >= 0 ? 0 : 1;
  50 }
  51 
  52 }
   1 /*
   2  * Copyright (c) 2007, 2020, 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 "jni.h"
  25 
  26 extern "C" {
  27 
  28 
  29 int always_true = 1;
  30 
  31 JNIEXPORT jint JNICALL
  32 Java_nsk_jdwp_ThreadReference_ForceEarlyReturn_forceEarlyReturn002_forceEarlyReturn002a_nativeMethod(JNIEnv *env, jobject classObject, jobject object)
  33 {

  34     // notify another thread that thread in native method
  35     jclass klass = env->GetObjectClass(object);
  36     jfieldID field = env->GetFieldID(klass, "threadInNative", "Z");
  37     env->SetBooleanField(object, field, 1);
  38 
  39     // attempt to read char from stdin instead of infinite loop
  40     // because infinite loop might be eliminated by compiler optimizer.
  41     fgetc(stdin);
  42 
  43     // should not reach here
  44     return -1;




  45 }
  46 
  47 }
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