Thu, 27 Jan 2011 16:11:27 -0800
6990754: Use native memory and reference counting to implement SymbolTable
Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank
1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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.
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23 */
25 #ifndef SHARE_VM_OOPS_KLASSVTABLE_HPP
26 #define SHARE_VM_OOPS_KLASSVTABLE_HPP
28 #include "memory/allocation.hpp"
29 #include "oops/oopsHierarchy.hpp"
30 #include "runtime/handles.hpp"
31 #include "utilities/growableArray.hpp"
33 // A klassVtable abstracts the variable-length vtable that is embedded in instanceKlass
34 // and arrayKlass. klassVtable objects are used just as convenient transient accessors to the vtable,
35 // not to actually hold the vtable data.
36 // Note: the klassVtable should not be accessed before the class has been verified
37 // (until that point, the vtable is uninitialized).
39 // Currently a klassVtable contains a direct reference to the vtable data, and is therefore
40 // not preserved across GCs.
42 class vtableEntry;
44 class klassVtable : public ResourceObj {
45 KlassHandle _klass; // my klass
46 int _tableOffset; // offset of start of vtable data within klass
47 int _length; // length of vtable (number of entries)
48 #ifndef PRODUCT
49 int _verify_count; // to make verify faster
50 #endif
52 // Ordering important, so greater_than (>) can be used as an merge operator.
53 enum AccessType {
54 acc_private = 0,
55 acc_package_private = 1,
56 acc_publicprotected = 2
57 };
59 public:
60 klassVtable(KlassHandle h_klass, void* base, int length) : _klass(h_klass) {
61 _tableOffset = (address)base - (address)h_klass(); _length = length;
62 }
64 // accessors
65 vtableEntry* table() const { return (vtableEntry*)(address(_klass()) + _tableOffset); }
66 KlassHandle klass() const { return _klass; }
67 int length() const { return _length; }
68 inline methodOop method_at(int i) const;
69 inline methodOop unchecked_method_at(int i) const;
70 inline oop* adr_method_at(int i) const;
72 // searching; all methods return -1 if not found
73 int index_of(methodOop m) const { return index_of(m, _length); }
74 int index_of_miranda(Symbol* name, Symbol* signature);
76 void initialize_vtable(bool checkconstraints, TRAPS); // initialize vtable of a new klass
78 // conputes vtable length (in words) and the number of miranda methods
79 static void compute_vtable_size_and_num_mirandas(int &vtable_length, int &num_miranda_methods,
80 klassOop super, objArrayOop methods,
81 AccessFlags class_flags, Handle classloader,
82 Symbol* classname, objArrayOop local_interfaces,
83 TRAPS);
85 // RedefineClasses() API support:
86 // If any entry of this vtable points to any of old_methods,
87 // replace it with the corresponding new_method.
88 // trace_name_printed is set to true if the current call has
89 // printed the klass name so that other routines in the adjust_*
90 // group don't print the klass name.
91 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
92 int methods_length, bool * trace_name_printed);
94 // Garbage collection
95 void oop_follow_contents();
96 void oop_adjust_pointers();
98 #ifndef SERIALGC
99 // Parallel Old
100 void oop_follow_contents(ParCompactionManager* cm);
101 void oop_update_pointers(ParCompactionManager* cm);
102 void oop_update_pointers(ParCompactionManager* cm,
103 HeapWord* beg_addr, HeapWord* end_addr);
104 #endif // SERIALGC
106 // Iterators
107 void oop_oop_iterate(OopClosure* blk);
108 void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
110 // Debugging code
111 void print() PRODUCT_RETURN;
112 void verify(outputStream* st, bool force = false);
113 static void print_statistics() PRODUCT_RETURN;
115 #ifndef PRODUCT
116 bool check_no_old_entries();
117 void dump_vtable();
118 #endif
120 protected:
121 friend class vtableEntry;
122 private:
123 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
124 void copy_vtable_to(vtableEntry* start);
125 int initialize_from_super(KlassHandle super);
126 int index_of(methodOop m, int len) const; // same as index_of, but search only up to len
127 void put_method_at(methodOop m, int index);
128 static bool needs_new_vtable_entry(methodHandle m, klassOop super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);
130 bool update_inherited_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);
131 instanceKlass* find_transitive_override(instanceKlass* initialsuper, methodHandle target_method, int vtable_index,
132 Handle target_loader, Symbol* target_classname, Thread* THREAD);
134 // support for miranda methods
135 bool is_miranda_entry_at(int i);
136 void fill_in_mirandas(int& initialized);
137 static bool is_miranda(methodOop m, objArrayOop class_methods, klassOop super);
138 static void add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas, objArrayOop current_interface_methods, objArrayOop class_methods, klassOop super);
139 static void get_mirandas(GrowableArray<methodOop>* mirandas, klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
140 static int get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);
143 void verify_against(outputStream* st, klassVtable* vt, int index);
144 inline instanceKlass* ik() const;
145 };
148 // private helper class for klassVtable
149 // description of entry points:
150 // destination is interpreted:
151 // from_compiled_code_entry_point -> c2iadapter
152 // from_interpreter_entry_point -> interpreter entry point
153 // destination is compiled:
154 // from_compiled_code_entry_point -> nmethod entry point
155 // from_interpreter_entry_point -> i2cadapter
156 class vtableEntry VALUE_OBJ_CLASS_SPEC {
157 public:
158 // size in words
159 static int size() {
160 return sizeof(vtableEntry) / sizeof(HeapWord);
161 }
162 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
163 methodOop method() const { return _method; }
165 private:
166 methodOop _method;
167 void set(methodOop method) { assert(method != NULL, "use clear"); _method = method; }
168 void clear() { _method = NULL; }
169 void print() PRODUCT_RETURN;
170 void verify(klassVtable* vt, outputStream* st);
172 friend class klassVtable;
173 };
176 inline methodOop klassVtable::method_at(int i) const {
177 assert(i >= 0 && i < _length, "index out of bounds");
178 assert(table()[i].method() != NULL, "should not be null");
179 assert(oop(table()[i].method())->is_method(), "should be method");
180 return table()[i].method();
181 }
183 inline methodOop klassVtable::unchecked_method_at(int i) const {
184 assert(i >= 0 && i < _length, "index out of bounds");
185 return table()[i].method();
186 }
188 inline oop* klassVtable::adr_method_at(int i) const {
189 // Allow one past the last entry to be referenced; useful for loop bounds.
190 assert(i >= 0 && i <= _length, "index out of bounds");
191 return (oop*)(address(table() + i) + vtableEntry::method_offset_in_bytes());
192 }
194 // --------------------------------------------------------------------------------
195 class klassItable;
196 class itableMethodEntry;
198 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {
199 private:
200 klassOop _interface;
201 int _offset;
202 public:
203 klassOop interface_klass() const { return _interface; }
204 int offset() const { return _offset; }
206 static itableMethodEntry* method_entry(klassOop k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
207 itableMethodEntry* first_method_entry(klassOop k) { return method_entry(k, _offset); }
209 void initialize(klassOop interf, int offset) { _interface = interf; _offset = offset; }
211 // Static size and offset accessors
212 static int size() { return sizeof(itableOffsetEntry) / HeapWordSize; } // size in words
213 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
214 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
216 friend class klassItable;
217 };
220 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {
221 private:
222 methodOop _method;
224 public:
225 methodOop method() const { return _method; }
227 void clear() { _method = NULL; }
229 void initialize(methodOop method);
231 // Static size and offset accessors
232 static int size() { return sizeof(itableMethodEntry) / HeapWordSize; } // size in words
233 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
235 friend class klassItable;
236 };
238 //
239 // Format of an itable
240 //
241 // ---- offset table ---
242 // klassOop of interface 1 \
243 // offset to vtable from start of oop / offset table entry
244 // ...
245 // klassOop of interface n \
246 // offset to vtable from start of oop / offset table entry
247 // --- vtable for interface 1 ---
248 // methodOop \
249 // compiler entry point / method table entry
250 // ...
251 // methodOop \
252 // compiler entry point / method table entry
253 // -- vtable for interface 2 ---
254 // ...
255 //
256 class klassItable : public ResourceObj {
257 private:
258 instanceKlassHandle _klass; // my klass
259 int _table_offset; // offset of start of itable data within klass (in words)
260 int _size_offset_table; // size of offset table (in itableOffset entries)
261 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
263 void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);
264 public:
265 klassItable(instanceKlassHandle klass);
267 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
268 return &((itableOffsetEntry*)vtable_start())[i]; }
270 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
271 return &((itableMethodEntry*)method_start())[i]; }
273 int size_offset_table() { return _size_offset_table; }
275 // Initialization
276 void initialize_itable(bool checkconstraints, TRAPS);
278 // Updates
279 void initialize_with_method(methodOop m);
281 // RedefineClasses() API support:
282 // if any entry of this itable points to any of old_methods,
283 // replace it with the corresponding new_method.
284 // trace_name_printed is set to true if the current call has
285 // printed the klass name so that other routines in the adjust_*
286 // group don't print the klass name.
287 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
288 int methods_length, bool * trace_name_printed);
290 // Garbage collection
291 void oop_follow_contents();
292 void oop_adjust_pointers();
294 #ifndef SERIALGC
295 // Parallel Old
296 void oop_follow_contents(ParCompactionManager* cm);
297 void oop_update_pointers(ParCompactionManager* cm);
298 void oop_update_pointers(ParCompactionManager* cm,
299 HeapWord* beg_addr, HeapWord* end_addr);
300 #endif // SERIALGC
302 // Iterators
303 void oop_oop_iterate(OopClosure* blk);
304 void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);
306 // Setup of itable
307 static int compute_itable_size(objArrayHandle transitive_interfaces);
308 static void setup_itable_offset_table(instanceKlassHandle klass);
310 // Resolving of method to index
311 static int compute_itable_index(methodOop m);
312 // ...and back again:
313 static methodOop method_for_itable_index(klassOop klass, int itable_index);
315 // Debugging/Statistics
316 static void print_statistics() PRODUCT_RETURN;
317 private:
318 intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }
319 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
321 // Helper methods
322 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
324 // Statistics
325 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables
326 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables
328 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
329 };
331 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP