1 #ifdef USE_PRAGMA_IDENT_HDR
2 #pragma ident "@(#)cpCacheOop.hpp 1.74 07/05/29 09:44:19 JVM"
3 #endif
4 /*
5 * Copyright 1998-2006 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 // A ConstantPoolCacheEntry describes an individual entry of the constant
29 // pool cache. There's 2 principal kinds of entries: field entries for in-
30 // stance & static field access, and method entries for invokes. Some of
31 // the entry layout is shared and looks as follows:
32 //
33 // bit number |31 0|
34 // bit length |-8--|-8--|---16----|
35 // --------------------------------
36 // _indices [ b2 | b1 | index ]
37 // _f1 [ entry specific ]
38 // _f2 [ entry specific ]
39 // _flags [t|f|vf|v|m|h|unused|field_index] (for field entries)
40 // bit length |4|1|1 |1|1|0|---7--|----16-----]
41 // _flags [t|f|vf|v|m|h|unused|eidx|psze] (for method entries)
42 // bit length |4|1|1 |1|1|1|---7--|-8--|-8--]
43
44 // --------------------------------
45 //
46 // with:
47 // index = original constant pool index
48 // b1 = bytecode 1
49 // b2 = bytecode 2
50 // psze = parameters size (method entries only)
51 // eidx = interpreter entry index (method entries only)
52 // field_index = index into field information in holder instanceKlass
53 // The index max is 0xffff (max number of fields in constant pool)
54 // and is multiplied by (instanceKlass::next_offset) when accessing.
55 // t = TosState (see below)
56 // f = field is marked final (see below)
57 // vf = virtual, final (method entries only : is_vfinal())
58 // v = field is volatile (see below)
59 // m = invokeinterface used for method in class Object (see below)
60 // h = RedefineClasses/Hotswap bit (see below)
61 //
62 // The flags after TosState have the following interpretation:
63 // bit 27: f flag true if field is marked final
64 // bit 26: vf flag true if virtual final method
65 // bit 25: v flag true if field is volatile (only for fields)
66 // bit 24: m flag true if invokeinterface used for method in class Object
67 // bit 23: 0 for fields, 1 for methods
68 //
69 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the
70 // following mapping to the TosState states:
71 //
72 // btos: 0
73 // ctos: 1
74 // stos: 2
75 // itos: 3
76 // ltos: 4
77 // ftos: 5
78 // dtos: 6
79 // atos: 7
80 // vtos: 8
81 //
82 // Entry specific: field entries:
83 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index
84 // _f1 = field holder
85 // _f2 = field offset in words
86 // _flags = field type information, original field index in field holder
87 // (field_index section)
88 //
89 // Entry specific: method entries:
90 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),
91 // original constant pool index
92 // _f1 = method for all but virtual calls, unused by virtual calls
93 // (note: for interface calls, which are essentially virtual,
94 // contains klassOop for the corresponding interface.
95 // _f2 = method/vtable index for virtual calls only, unused by all other
96 // calls. The vf flag indicates this is a method pointer not an
97 // index.
98 // _flags = field type info (f section),
99 // virtual final entry (vf),
100 // interpreter entry index (eidx section),
101 // parameter size (psze section)
102 //
103 // Note: invokevirtual & invokespecial bytecodes can share the same constant
104 // pool entry and thus the same constant pool cache entry. All invoke
105 // bytecodes but invokevirtual use only _f1 and the corresponding b1
106 // bytecode, while invokevirtual uses only _f2 and the corresponding
107 // b2 bytecode. The value of _flags is shared for both types of entries.
108 //
109 // The fields are volatile so that they are stored in the order written in the
110 // source code. The _indices field with the bytecode must be written last.
111
112 class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {
113 friend class VMStructs;
114 private:
115 volatile intx _indices; // constant pool index & rewrite bytecodes
116 volatile oop _f1; // entry specific oop field
117 volatile intx _f2; // entry specific int/oop field
118 volatile intx _flags; // flags
119
120
121 #ifdef ASSERT
122 bool same_methodOop(oop cur_f1, oop f1);
123 #endif
124
125 void set_bytecode_1(Bytecodes::Code code);
126 void set_bytecode_2(Bytecodes::Code code);
127 void set_f1(oop f1) {
128 oop existing_f1 = _f1; // read once
129 assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");
130 oop_store(&_f1, f1);
131 }
132 void set_f2(intx f2) { assert(_f2 == 0 || _f2 == f2, "illegal field change"); _f2 = f2; }
133 int as_flags(TosState state, bool is_final, bool is_vfinal, bool is_volatile,
134 bool is_method_interface, bool is_method);
135 void set_flags(intx flags) { _flags = flags; }
136
137 public:
138 // specific bit values in flag field
139 // Note: the interpreter knows this layout!
140 enum FlagBitValues {
141 hotSwapBit = 23,
142 methodInterface = 24,
143 volatileField = 25,
144 vfinalMethod = 26,
145 finalField = 27
146 };
147
148 enum { field_index_mask = 0xFFFF };
149
150 // start of type bits in flags
151 // Note: the interpreter knows this layout!
152 enum FlagValues {
153 tosBits = 28
154 };
155
156 // Initialization
157 void set_initial_state(int index); // sets entry to initial state
158
159 void set_field( // sets entry to resolved field state
160 Bytecodes::Code get_code, // the bytecode used for reading the field
161 Bytecodes::Code put_code, // the bytecode used for writing the field
162 KlassHandle field_holder, // the object/klass holding the field
163 int orig_field_index, // the original field index in the field holder
164 int field_offset, // the field offset in words in the field holder
165 TosState field_type, // the (machine) field type
166 bool is_final, // the field is final
167 bool is_volatile // the field is volatile
168 );
169
170 void set_method( // sets entry to resolved method entry
171 Bytecodes::Code invoke_code, // the bytecode used for invoking the method
172 methodHandle method, // the method/prototype if any (NULL, otherwise)
173 int vtable_index // the vtable index if any, else negative
174 );
175
176 void set_interface_call(
177 methodHandle method, // Resolved method
178 int index // Method index into interface
179 );
180
181 void set_parameter_size(int value) {
182 assert(parameter_size() == 0 || parameter_size() == value,
183 "size must not change");
184 // Setting the parameter size by itself is only safe if the
185 // current value of _flags is 0, otherwise another thread may have
186 // updated it and we don't want to overwrite that value. Don't
187 // bother trying to update it once it's nonzero but always make
188 // sure that the final parameter size agrees with what was passed.
189 if (_flags == 0) {
190 Atomic::cmpxchg_ptr((value & 0xFF), &_flags, 0);
191 }
192 guarantee(parameter_size() == value, "size must not change");
193 }
194
195 // Which bytecode number (1 or 2) in the index field is valid for this bytecode?
196 // Returns -1 if neither is valid.
197 static int bytecode_number(Bytecodes::Code code) {
198 switch (code) {
199 case Bytecodes::_getstatic : // fall through
200 case Bytecodes::_getfield : // fall through
201 case Bytecodes::_invokespecial : // fall through
202 case Bytecodes::_invokestatic : // fall through
203 case Bytecodes::_invokeinterface : return 1;
204 case Bytecodes::_putstatic : // fall through
205 case Bytecodes::_putfield : // fall through
206 case Bytecodes::_invokevirtual : return 2;
207 default : break;
208 }
209 return -1;
210 }
211
212 // Has this bytecode been resolved? Only valid for invokes and get/put field/static.
213 bool is_resolved(Bytecodes::Code code) const {
214 switch (bytecode_number(code)) {
215 case 1: return (bytecode_1() == code);
216 case 2: return (bytecode_2() == code);
217 }
218 return false; // default: not resolved
219 }
220
221 // Accessors
222 int constant_pool_index() const { return _indices & 0xFFFF; }
223 Bytecodes::Code bytecode_1() const { return Bytecodes::cast((_indices >> 16) & 0xFF); }
224 Bytecodes::Code bytecode_2() const { return Bytecodes::cast((_indices >> 24) & 0xFF); }
225 volatile oop f1() const { return _f1; }
226 intx f2() const { return _f2; }
227 int field_index() const;
228 int parameter_size() const { return _flags & 0xFF; }
229 bool is_vfinal() const { return ((_flags & (1 << vfinalMethod)) == (1 << vfinalMethod)); }
230 bool is_volatile() const { return ((_flags & (1 << volatileField)) == (1 << volatileField)); }
231 bool is_methodInterface() const { return ((_flags & (1 << methodInterface)) == (1 << methodInterface)); }
232 bool is_byte() const { return (((uintx) _flags >> tosBits) == btos); }
233 bool is_char() const { return (((uintx) _flags >> tosBits) == ctos); }
234 bool is_short() const { return (((uintx) _flags >> tosBits) == stos); }
235 bool is_int() const { return (((uintx) _flags >> tosBits) == itos); }
236 bool is_long() const { return (((uintx) _flags >> tosBits) == ltos); }
237 bool is_float() const { return (((uintx) _flags >> tosBits) == ftos); }
238 bool is_double() const { return (((uintx) _flags >> tosBits) == dtos); }
239 bool is_object() const { return (((uintx) _flags >> tosBits) == atos); }
240 TosState flag_state() const { assert( ( (_flags >> tosBits) & 0x0F ) < number_of_states, "Invalid state in as_flags");
241 return (TosState)((_flags >> tosBits) & 0x0F); }
242
243 // Code generation support
244 static WordSize size() { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }
245 static ByteSize indices_offset() { return byte_offset_of(ConstantPoolCacheEntry, _indices); }
246 static ByteSize f1_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f1); }
247 static ByteSize f2_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f2); }
248 static ByteSize flags_offset() { return byte_offset_of(ConstantPoolCacheEntry, _flags); }
249
250 // GC Support
251 void oops_do(void f(oop*));
252 void oop_iterate(OopClosure* blk);
253 void oop_iterate_m(OopClosure* blk, MemRegion mr);
254 void follow_contents();
255 void adjust_pointers();
256
257 #ifndef SERIALGC
258 // Parallel Old
259 void follow_contents(ParCompactionManager* cm);
260 #endif // SERIALGC
261
262 void update_pointers();
263 void update_pointers(HeapWord* beg_addr, HeapWord* end_addr);
264
265 // RedefineClasses() API support:
266 // If this constantPoolCacheEntry refers to old_method then update it
267 // to refer to new_method.
268 // trace_name_printed is set to true if the current call has
269 // printed the klass name so that other routines in the adjust_*
270 // group don't print the klass name.
271 bool adjust_method_entry(methodOop old_method, methodOop new_method,
272 bool * trace_name_printed);
273 bool is_interesting_method_entry(klassOop k);
274 bool is_field_entry() const { return (_flags & (1 << hotSwapBit)) == 0; }
275 bool is_method_entry() const { return (_flags & (1 << hotSwapBit)) != 0; }
276
277 // Debugging & Printing
278 void print (outputStream* st, int index) const;
279 void verify(outputStream* st) const;
280
281 static void verify_tosBits() {
282 assert(tosBits == 28, "interpreter now assumes tosBits is 28");
283 }
284 };
285
286
287 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache
288 // holds interpreter runtime information for all field access and invoke bytecodes. The cache
289 // is created and initialized before a class is actively used (i.e., initialized), the indivi-
290 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).
291
292 class constantPoolCacheOopDesc: public arrayOopDesc {
293 friend class VMStructs;
294 private:
295 constantPoolOop _constant_pool; // the corresponding constant pool
296
297 // Sizing
298 static int header_size() { return sizeof(constantPoolCacheOopDesc) / HeapWordSize; }
299 static int object_size(int length) { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }
300 int object_size() { return object_size(length()); }
301
302 // Helpers
303 constantPoolOop* constant_pool_addr() { return &_constant_pool; }
304 ConstantPoolCacheEntry* base() const { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }
305
306 friend class constantPoolCacheKlass;
307
308 public:
309 // Initialization
310 void initialize(intArray& inverse_index_map);
311
312 // Accessors
313 void set_constant_pool(constantPoolOop pool) { oop_store_without_check((oop*)&_constant_pool, (oop)pool); }
314 constantPoolOop constant_pool() const { return _constant_pool; }
315 ConstantPoolCacheEntry* entry_at(int i) const { assert(0 <= i && i < length(), "index out of bounds"); return base() + i; }
316
317 // Code generation
318 static ByteSize base_offset() { return in_ByteSize(sizeof(constantPoolCacheOopDesc)); }
319
320 // RedefineClasses() API support:
321 // If any entry of this constantPoolCache points to any of
322 // old_methods, replace it with the corresponding new_method.
323 // trace_name_printed is set to true if the current call has
324 // printed the klass name so that other routines in the adjust_*
325 // group don't print the klass name.
326 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
327 int methods_length, bool * trace_name_printed);
328 };
329