Mercurial > hg > graal-jvmci-8
annotate src/share/vm/runtime/jniHandles.hpp @ 973:ad6585fd4087
6830542: Performance: JVM_DefineClass already verified.
Reviewed-by: kamg, phh
author | acorn |
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date | Fri, 04 Sep 2009 12:53:02 -0400 |
parents | 1760a1cbed36 |
children | 354d3184f6b2 d3562366cbfd |
rev | line source |
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0 | 1 /* |
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2 * Copyright 1998-2009 Sun Microsystems, Inc. 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 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 class JNIHandleBlock; | |
26 | |
27 | |
28 // Interface for creating and resolving local/global JNI handles | |
29 | |
30 class JNIHandles : AllStatic { | |
31 friend class VMStructs; | |
32 private: | |
33 static JNIHandleBlock* _global_handles; // First global handle block | |
34 static JNIHandleBlock* _weak_global_handles; // First weak global handle block | |
35 static oop _deleted_handle; // Sentinel marking deleted handles | |
36 | |
37 public: | |
38 // Resolve handle into oop | |
39 inline static oop resolve(jobject handle); | |
40 // Resolve externally provided handle into oop with some guards | |
41 inline static oop resolve_external_guard(jobject handle); | |
42 // Resolve handle into oop, result guaranteed not to be null | |
43 inline static oop resolve_non_null(jobject handle); | |
44 | |
45 // Local handles | |
46 static jobject make_local(oop obj); | |
47 static jobject make_local(JNIEnv* env, oop obj); // Fast version when env is known | |
48 static jobject make_local(Thread* thread, oop obj); // Even faster version when current thread is known | |
49 inline static void destroy_local(jobject handle); | |
50 | |
51 // Global handles | |
52 static jobject make_global(Handle obj); | |
53 static void destroy_global(jobject handle); | |
54 | |
55 // Weak global handles | |
56 static jobject make_weak_global(Handle obj); | |
57 static void destroy_weak_global(jobject handle); | |
58 | |
59 // jmethodID handling (as Weak global handles). | |
60 // Because the useful life-span of a jmethodID cannot be determined, once created they are | |
61 // never reclaimed. The methods to which they refer, however, can be GC'ed away if the class | |
62 // is unloaded or if the method is made obsolete or deleted -- in these cases, the jmethodID | |
63 // refers to NULL (as is the case for any weak reference). | |
64 static jmethodID make_jmethod_id(methodHandle mh); | |
65 static void destroy_jmethod_id(jmethodID mid); | |
66 inline static methodOop resolve_jmethod_id(jmethodID mid); | |
67 inline static methodOop checked_resolve_jmethod_id(jmethodID mid); // NULL on invalid jmethodID | |
68 static void change_method_associated_with_jmethod_id(jmethodID jmid, methodHandle mh); | |
69 | |
70 // Sentinel marking deleted handles in block. Note that we cannot store NULL as | |
71 // the sentinel, since clearing weak global JNI refs are done by storing NULL in | |
72 // the handle. The handle may not be reused before destroy_weak_global is called. | |
73 static oop deleted_handle() { return _deleted_handle; } | |
74 | |
75 // Initialization | |
76 static void initialize(); | |
77 | |
78 // Debugging | |
79 static void print_on(outputStream* st); | |
80 static void print() { print_on(tty); } | |
81 static void verify(); | |
82 static bool is_local_handle(Thread* thread, jobject handle); | |
83 static bool is_frame_handle(JavaThread* thr, jobject obj); | |
84 static bool is_global_handle(jobject handle); | |
85 static bool is_weak_global_handle(jobject handle); | |
86 static long global_handle_memory_usage(); | |
87 static long weak_global_handle_memory_usage(); | |
88 | |
89 // Garbage collection support(global handles only, local handles are traversed from thread) | |
90 // Traversal of regular global handles | |
91 static void oops_do(OopClosure* f); | |
92 // Traversal of weak global handles. Unreachable oops are cleared. | |
93 static void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f); | |
94 }; | |
95 | |
96 | |
97 | |
98 // JNI handle blocks holding local/global JNI handles | |
99 | |
100 class JNIHandleBlock : public CHeapObj { | |
101 friend class VMStructs; | |
102 private: | |
103 enum SomeConstants { | |
104 block_size_in_oops = 32 // Number of handles per handle block | |
105 }; | |
106 | |
107 oop _handles[block_size_in_oops]; // The handles | |
108 int _top; // Index of next unused handle | |
109 JNIHandleBlock* _next; // Link to next block | |
110 | |
111 // The following instance variables are only used by the first block in a chain. | |
112 // Having two types of blocks complicates the code and the space overhead in negligble. | |
113 JNIHandleBlock* _last; // Last block in use | |
114 JNIHandleBlock* _pop_frame_link; // Block to restore on PopLocalFrame call | |
115 oop* _free_list; // Handle free list | |
116 int _allocate_before_rebuild; // Number of blocks to allocate before rebuilding free list | |
117 | |
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 | |
129 // No more handles in the both the current and following blocks | |
130 void clear() { _top = 0; } | |
131 | |
132 // Free list computation | |
133 void rebuild_free_list(); | |
134 | |
135 public: | |
136 // Handle allocation | |
137 jobject allocate_handle(oop obj); | |
138 | |
139 // Block allocation and block free list management | |
140 static JNIHandleBlock* allocate_block(Thread* thread = NULL); | |
141 static void release_block(JNIHandleBlock* block, Thread* thread = NULL); | |
142 | |
143 // JNI PushLocalFrame/PopLocalFrame support | |
144 JNIHandleBlock* pop_frame_link() const { return _pop_frame_link; } | |
145 void set_pop_frame_link(JNIHandleBlock* block) { _pop_frame_link = block; } | |
146 | |
147 // Stub generator support | |
148 static int top_offset_in_bytes() { return offset_of(JNIHandleBlock, _top); } | |
149 | |
150 // Garbage collection support | |
151 // Traversal of regular handles | |
152 void oops_do(OopClosure* f); | |
153 // Traversal of weak handles. Unreachable oops are cleared. | |
154 void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f); | |
155 | |
156 // Debugging | |
157 bool chain_contains(jobject handle) const; // Does this block or following blocks contain handle | |
158 bool contains(jobject handle) const; // Does this block contain handle | |
159 int length() const; // Length of chain starting with this block | |
160 long memory_usage() const; | |
161 #ifndef PRODUCT | |
162 static bool any_contains(jobject handle); // Does any block currently in use contain handle | |
163 static void print_statistics(); | |
164 #endif | |
165 }; | |
166 | |
167 | |
168 inline oop JNIHandles::resolve(jobject handle) { | |
169 oop result = (handle == NULL ? (oop)NULL : *(oop*)handle); | |
170 assert(result != NULL || (handle == NULL || !CheckJNICalls || is_weak_global_handle(handle)), "Invalid value read from jni handle"); | |
171 assert(result != badJNIHandle, "Pointing to zapped jni handle area"); | |
172 return result; | |
173 }; | |
174 | |
175 | |
176 inline oop JNIHandles::resolve_external_guard(jobject handle) { | |
177 if (handle == NULL) return NULL; | |
178 oop result = *(oop*)handle; | |
179 if (result == NULL || result == badJNIHandle) return NULL; | |
180 return result; | |
181 }; | |
182 | |
183 | |
184 inline oop JNIHandles::resolve_non_null(jobject handle) { | |
185 assert(handle != NULL, "JNI handle should not be null"); | |
186 oop result = *(oop*)handle; | |
187 assert(result != NULL, "Invalid value read from jni handle"); | |
188 assert(result != badJNIHandle, "Pointing to zapped jni handle area"); | |
189 // Don't let that private _deleted_handle object escape into the wild. | |
190 assert(result != deleted_handle(), "Used a deleted global handle."); | |
191 return result; | |
192 }; | |
193 | |
194 inline methodOop JNIHandles::resolve_jmethod_id(jmethodID mid) { | |
195 return (methodOop) resolve_non_null((jobject)mid); | |
196 }; | |
197 | |
198 inline methodOop JNIHandles::checked_resolve_jmethod_id(jmethodID mid) { | |
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199 if (mid == NULL) { |
0 | 200 return (methodOop) NULL; |
201 } | |
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202 |
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203 oop o = resolve_non_null((jobject) mid); |
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204 if (!o->is_method()) { |
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205 return (methodOop) NULL; |
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206 } |
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207 |
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208 return (methodOop) o; |
0 | 209 }; |
210 | |
211 | |
212 inline void JNIHandles::destroy_local(jobject handle) { | |
213 if (handle != NULL) { | |
214 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
215 } | |
216 } |