1 /*
 2  * Copyright (c) 2026, 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 <stdio.h>
25 #include <string.h>
26 #include "jvmti.h"
27 #include "jni.h"
28 #include "jvmti_common.hpp"
29 
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33 
34 static jvmtiEnv *jvmti = nullptr;
35 static jobject cached_this = nullptr;
36 
37 JNIEXPORT jint JNICALL
38 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
39   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
40   if (res != JNI_OK || jvmti == nullptr) {
41     LOG("GetEnv failed, res = %d", (int)res);
42     return JNI_ERR;
43   }
44 
45   jvmtiCapabilities caps;
46   memset(&caps, 0, sizeof(caps));
47   caps.can_access_local_variables = 1;
48   jvmtiError err = jvmti->AddCapabilities(&caps);
49   if (err != JVMTI_ERROR_NONE) {
50     LOG("AddCapabilities failed: %s (%d)\n", TranslateError(err), err);
51     return JNI_ERR;
52   }
53 
54   return JNI_OK;
55 }
56 
57 JNIEXPORT void JNICALL
58 Java_ValueGetCtorLocal_testCtorThis(JNIEnv *jni, jclass thisClass, jthread thread) {
59   const jint depth = 1;
60 
61   jmethodID method = get_frame_method(jvmti, jni, thread, depth);
62   char* mname = get_method_name(jvmti, jni, method);
63 
64   LOG("\ntestCtorThis: frame method: %s\n", mname);
65   jobject obj0 = get_local_object(jvmti, jni, thread, depth, 0);
66   jobject obj_this = get_local_instance(jvmti, jni, thread, depth);
67 
68   // obj0 is expected to be equal to "this"
69   jboolean is_equal = jni->IsSameObject(obj0, obj_this);
70   LOG("testCtorThis: obj0: %p obj_this: %p objects are equal: %d\n",
71       (void*)obj0, (void*)obj_this, is_equal);
72 
73   if (!is_equal) {
74     fatal(jni, "Failed: obj0 != obj_this\n");
75   }
76   if (cached_this == nullptr) { // first call to testCtorThis
77     cached_this = jni->NewGlobalRef(obj_this);
78   } else {
79     // cached_this must be a snapshot that does not mutate
80     // when the ctor changes field values
81     if (jni->IsSameObject(cached_this, obj_this)) {
82       fatal(jni, "Failed: unexpected: cached_this == obj_this\n");
83     }
84   }
85   deallocate(jvmti, jni, (void*)mname);
86 }
87 
88 #ifdef __cplusplus
89 }
90 #endif