Mercurial > hg > truffle
annotate src/share/vm/runtime/jniHandles.hpp @ 13563:fb846424299f
Truffle/Ruby: extend Instrumentation framework with language-agnostic interfaces for access to AST printing utilities and a Ruby implementation
author | Michael Van De Vanter <michael.van.de.vanter@oracle.com> |
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date | Tue, 07 Jan 2014 18:09:42 -0800 |
parents | da91efe96a93 |
children | 63a4eb8bcd23 |
rev | line source |
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0 | 1 /* |
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6964458: Reimplement class meta-data storage to use native memory
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2 * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved. |
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5 * This code is free software; you can redistribute it and/or modify it | |
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12 * version 2 for more details (a copy is included in the LICENSE file that | |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
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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 | |
115 #ifndef PRODUCT | |
116 JNIHandleBlock* _block_list_link; // Link for list below | |
117 static JNIHandleBlock* _block_list; // List of all allocated blocks (for debugging only) | |
118 #endif | |
119 | |
120 static JNIHandleBlock* _block_free_list; // Free list of currently unused blocks | |
121 static int _blocks_allocated; // For debugging/printing | |
122 | |
123 // Fill block with bad_handle values | |
124 void zap(); | |
125 | |
1010 | 126 protected: |
0 | 127 // No more handles in the both the current and following blocks |
128 void clear() { _top = 0; } | |
129 | |
1010 | 130 private: |
0 | 131 // Free list computation |
132 void rebuild_free_list(); | |
133 | |
134 public: | |
135 // Handle allocation | |
136 jobject allocate_handle(oop obj); | |
137 | |
138 // Block allocation and block free list management | |
139 static JNIHandleBlock* allocate_block(Thread* thread = NULL); | |
140 static void release_block(JNIHandleBlock* block, Thread* thread = NULL); | |
141 | |
142 // JNI PushLocalFrame/PopLocalFrame support | |
143 JNIHandleBlock* pop_frame_link() const { return _pop_frame_link; } | |
144 void set_pop_frame_link(JNIHandleBlock* block) { _pop_frame_link = block; } | |
145 | |
146 // Stub generator support | |
147 static int top_offset_in_bytes() { return offset_of(JNIHandleBlock, _top); } | |
148 | |
149 // Garbage collection support | |
150 // Traversal of regular handles | |
151 void oops_do(OopClosure* f); | |
152 // Traversal of weak handles. Unreachable oops are cleared. | |
153 void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f); | |
154 | |
155 // Debugging | |
156 bool chain_contains(jobject handle) const; // Does this block or following blocks contain handle | |
157 bool contains(jobject handle) const; // Does this block contain handle | |
158 int length() const; // Length of chain starting with this block | |
159 long memory_usage() const; | |
160 #ifndef PRODUCT | |
161 static bool any_contains(jobject handle); // Does any block currently in use contain handle | |
162 static void print_statistics(); | |
163 #endif | |
164 }; | |
165 | |
166 | |
167 inline oop JNIHandles::resolve(jobject handle) { | |
168 oop result = (handle == NULL ? (oop)NULL : *(oop*)handle); | |
169 assert(result != NULL || (handle == NULL || !CheckJNICalls || is_weak_global_handle(handle)), "Invalid value read from jni handle"); | |
170 assert(result != badJNIHandle, "Pointing to zapped jni handle area"); | |
171 return result; | |
172 }; | |
173 | |
174 | |
175 inline oop JNIHandles::resolve_external_guard(jobject handle) { | |
176 if (handle == NULL) return NULL; | |
177 oop result = *(oop*)handle; | |
178 if (result == NULL || result == badJNIHandle) return NULL; | |
179 return result; | |
180 }; | |
181 | |
182 | |
183 inline oop JNIHandles::resolve_non_null(jobject handle) { | |
184 assert(handle != NULL, "JNI handle should not be null"); | |
185 oop result = *(oop*)handle; | |
186 assert(result != NULL, "Invalid value read from jni handle"); | |
187 assert(result != badJNIHandle, "Pointing to zapped jni handle area"); | |
188 // Don't let that private _deleted_handle object escape into the wild. | |
189 assert(result != deleted_handle(), "Used a deleted global handle."); | |
190 return result; | |
191 }; | |
192 | |
193 inline void JNIHandles::destroy_local(jobject handle) { | |
194 if (handle != NULL) { | |
195 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
196 } | |
197 } | |
1972 | 198 |
199 #endif // SHARE_VM_RUNTIME_JNIHANDLES_HPP |