Mercurial > hg > graal-jvmci-8
annotate src/share/vm/runtime/jniHandles.hpp @ 24234:ea6f94ab283b default tip
Added tag jvmci-0.36 for changeset 8128b98d4736
author | Gilles Duboscq <gilles.m.duboscq@oracle.com> |
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date | Mon, 18 Sep 2017 18:49:45 +0200 |
parents | dd9cc155639c |
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0 | 1 /* |
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2 * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_RUNTIME_JNIHANDLES_HPP |
26 #define SHARE_VM_RUNTIME_JNIHANDLES_HPP | |
27 | |
28 #include "runtime/handles.hpp" | |
29 #include "utilities/top.hpp" | |
30 | |
0 | 31 class JNIHandleBlock; |
32 | |
33 | |
34 // Interface for creating and resolving local/global JNI handles | |
35 | |
36 class JNIHandles : AllStatic { | |
37 friend class VMStructs; | |
38 private: | |
39 static JNIHandleBlock* _global_handles; // First global handle block | |
40 static JNIHandleBlock* _weak_global_handles; // First weak global handle block | |
41 static oop _deleted_handle; // Sentinel marking deleted handles | |
42 | |
43 public: | |
44 // Resolve handle into oop | |
45 inline static oop resolve(jobject handle); | |
46 // Resolve externally provided handle into oop with some guards | |
47 inline static oop resolve_external_guard(jobject handle); | |
48 // Resolve handle into oop, result guaranteed not to be null | |
49 inline static oop resolve_non_null(jobject handle); | |
50 | |
51 // Local handles | |
52 static jobject make_local(oop obj); | |
53 static jobject make_local(JNIEnv* env, oop obj); // Fast version when env is known | |
54 static jobject make_local(Thread* thread, oop obj); // Even faster version when current thread is known | |
55 inline static void destroy_local(jobject handle); | |
56 | |
57 // Global handles | |
58 static jobject make_global(Handle obj); | |
59 static void destroy_global(jobject handle); | |
60 | |
61 // Weak global handles | |
62 static jobject make_weak_global(Handle obj); | |
63 static void destroy_weak_global(jobject handle); | |
64 | |
65 // Sentinel marking deleted handles in block. Note that we cannot store NULL as | |
66 // the sentinel, since clearing weak global JNI refs are done by storing NULL in | |
67 // the handle. The handle may not be reused before destroy_weak_global is called. | |
68 static oop deleted_handle() { return _deleted_handle; } | |
69 | |
70 // Initialization | |
71 static void initialize(); | |
72 | |
73 // Debugging | |
74 static void print_on(outputStream* st); | |
75 static void print() { print_on(tty); } | |
76 static void verify(); | |
77 static bool is_local_handle(Thread* thread, jobject handle); | |
78 static bool is_frame_handle(JavaThread* thr, jobject obj); | |
79 static bool is_global_handle(jobject handle); | |
80 static bool is_weak_global_handle(jobject handle); | |
81 static long global_handle_memory_usage(); | |
82 static long weak_global_handle_memory_usage(); | |
83 | |
84 // Garbage collection support(global handles only, local handles are traversed from thread) | |
85 // Traversal of regular global handles | |
86 static void oops_do(OopClosure* f); | |
87 // Traversal of weak global handles. Unreachable oops are cleared. | |
88 static void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f); | |
89 }; | |
90 | |
91 | |
92 | |
93 // JNI handle blocks holding local/global JNI handles | |
94 | |
6197 | 95 class JNIHandleBlock : public CHeapObj<mtInternal> { |
0 | 96 friend class VMStructs; |
1010 | 97 friend class CppInterpreter; |
98 | |
0 | 99 private: |
100 enum SomeConstants { | |
101 block_size_in_oops = 32 // Number of handles per handle block | |
102 }; | |
103 | |
104 oop _handles[block_size_in_oops]; // The handles | |
105 int _top; // Index of next unused handle | |
106 JNIHandleBlock* _next; // Link to next block | |
107 | |
108 // The following instance variables are only used by the first block in a chain. | |
109 // Having two types of blocks complicates the code and the space overhead in negligble. | |
110 JNIHandleBlock* _last; // Last block in use | |
111 JNIHandleBlock* _pop_frame_link; // Block to restore on PopLocalFrame call | |
112 oop* _free_list; // Handle free list | |
113 int _allocate_before_rebuild; // Number of blocks to allocate before rebuilding free list | |
114 | |
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115 // Check JNI, "planned capacity" for current frame (or push/ensure) |
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116 size_t _planned_capacity; |
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117 |
0 | 118 #ifndef PRODUCT |
119 JNIHandleBlock* _block_list_link; // Link for list below | |
120 static JNIHandleBlock* _block_list; // List of all allocated blocks (for debugging only) | |
121 #endif | |
122 | |
123 static JNIHandleBlock* _block_free_list; // Free list of currently unused blocks | |
124 static int _blocks_allocated; // For debugging/printing | |
125 | |
126 // Fill block with bad_handle values | |
127 void zap(); | |
128 | |
1010 | 129 protected: |
0 | 130 // No more handles in the both the current and following blocks |
131 void clear() { _top = 0; } | |
132 | |
1010 | 133 private: |
0 | 134 // Free list computation |
135 void rebuild_free_list(); | |
136 | |
137 public: | |
138 // Handle allocation | |
139 jobject allocate_handle(oop obj); | |
140 | |
141 // Block allocation and block free list management | |
142 static JNIHandleBlock* allocate_block(Thread* thread = NULL); | |
143 static void release_block(JNIHandleBlock* block, Thread* thread = NULL); | |
144 | |
145 // JNI PushLocalFrame/PopLocalFrame support | |
146 JNIHandleBlock* pop_frame_link() const { return _pop_frame_link; } | |
147 void set_pop_frame_link(JNIHandleBlock* block) { _pop_frame_link = block; } | |
148 | |
149 // Stub generator support | |
150 static int top_offset_in_bytes() { return offset_of(JNIHandleBlock, _top); } | |
151 | |
152 // Garbage collection support | |
153 // Traversal of regular handles | |
154 void oops_do(OopClosure* f); | |
155 // Traversal of weak handles. Unreachable oops are cleared. | |
156 void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f); | |
157 | |
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158 // Checked JNI support |
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159 void set_planned_capacity(size_t planned_capacity) { _planned_capacity = planned_capacity; } |
d68158e12cea
8043224: -Xcheck:jni improvements to exception checking and excessive local refs
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160 const size_t get_planned_capacity() { return _planned_capacity; } |
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161 const size_t get_number_of_live_handles(); |
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162 |
0 | 163 // Debugging |
164 bool chain_contains(jobject handle) const; // Does this block or following blocks contain handle | |
165 bool contains(jobject handle) const; // Does this block contain handle | |
166 int length() const; // Length of chain starting with this block | |
167 long memory_usage() const; | |
168 #ifndef PRODUCT | |
169 static bool any_contains(jobject handle); // Does any block currently in use contain handle | |
170 static void print_statistics(); | |
171 #endif | |
172 }; | |
173 | |
174 | |
175 inline oop JNIHandles::resolve(jobject handle) { | |
176 oop result = (handle == NULL ? (oop)NULL : *(oop*)handle); | |
177 assert(result != NULL || (handle == NULL || !CheckJNICalls || is_weak_global_handle(handle)), "Invalid value read from jni handle"); | |
178 assert(result != badJNIHandle, "Pointing to zapped jni handle area"); | |
179 return result; | |
180 }; | |
181 | |
182 | |
183 inline oop JNIHandles::resolve_external_guard(jobject handle) { | |
184 if (handle == NULL) return NULL; | |
185 oop result = *(oop*)handle; | |
186 if (result == NULL || result == badJNIHandle) return NULL; | |
187 return result; | |
188 }; | |
189 | |
190 | |
191 inline oop JNIHandles::resolve_non_null(jobject handle) { | |
192 assert(handle != NULL, "JNI handle should not be null"); | |
193 oop result = *(oop*)handle; | |
194 assert(result != NULL, "Invalid value read from jni handle"); | |
195 assert(result != badJNIHandle, "Pointing to zapped jni handle area"); | |
196 // Don't let that private _deleted_handle object escape into the wild. | |
197 assert(result != deleted_handle(), "Used a deleted global handle."); | |
198 return result; | |
199 }; | |
200 | |
201 inline void JNIHandles::destroy_local(jobject handle) { | |
202 if (handle != NULL) { | |
203 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
204 } | |
205 } | |
1972 | 206 |
207 #endif // SHARE_VM_RUNTIME_JNIHANDLES_HPP |