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.
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "memory/gcLocker.hpp"
28 #include "oops/oop.inline.hpp"
29 #include "oops/symbolKlass.hpp"
30 #include "oops/symbolOop.hpp"
31 #include "runtime/handles.inline.hpp"
32
33 symbolOop symbolKlass::allocate_symbol(u1* name, int len, TRAPS) {
34 // Don't allow symbol oops to be created which cannot fit in a symbolOop.
35 if (len > symbolOopDesc::max_length()) {
36 THROW_MSG_0(vmSymbols::java_lang_InternalError(),
37 "name is too long to represent");
38 }
39 int size = symbolOopDesc::object_size(len);
40 symbolKlassHandle h_k(THREAD, as_klassOop());
41 symbolOop sym = (symbolOop)
42 CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
43 assert(!sym->is_parsable(), "not expecting parsability yet.");
44 No_Safepoint_Verifier no_safepoint;
45 sym->set_utf8_length(len);
46 for (int i = 0; i < len; i++) {
47 sym->byte_at_put(i, name[i]);
48 }
49 // Let the first emptySymbol be created and
50 // ensure only one is ever created.
51 assert(sym->is_parsable() || Universe::emptySymbol() == NULL,
52 "should be parsable here.");
53 return sym;
54 }
55
56 bool symbolKlass::allocate_symbols(int names_count, const char** names,
57 int* lengths, symbolOop* sym_oops, TRAPS) {
58 if (UseConcMarkSweepGC || UseParallelGC) {
59 // Concurrent GC needs to mark all the allocated symbol oops after
60 // the remark phase which isn't done below (except the first symbol oop).
61 // So return false which will let the symbols be allocated one by one.
62 // The parallel collector uses an object start array to find the
63 // start of objects on a dirty card. The object start array is not
64 // updated for the start of each symbol so is not precise. During
65 // object array verification this causes a verification failure.
66 // In a product build this causes extra searching for the start of
67 // a symbol. As with the concurrent collector a return of false will
68 // cause each symbol to be allocated separately and in the case
69 // of the parallel collector will cause the object
70 // start array to be updated.
71 return false;
72 }
73
74 assert(names_count > 0, "can't allocate 0 symbols");
75
76 int total_size = 0;
77 int i, sizes[SymbolTable::symbol_alloc_batch_size];
78 for (i=0; i<names_count; i++) {
79 int len = lengths[i];
80 if (len > symbolOopDesc::max_length()) {
81 return false;
82 }
83 int sz = symbolOopDesc::object_size(len);
84 sizes[i] = sz * HeapWordSize;
85 total_size += sz;
86 }
87 symbolKlassHandle h_k(THREAD, as_klassOop());
88 HeapWord* base = Universe::heap()->permanent_mem_allocate(total_size);
89 if (base == NULL) {
90 return false;
91 }
92
93 // CAN'T take any safepoint during the initialization of the symbol oops !
94 No_Safepoint_Verifier nosafepoint;
95
96 klassOop sk = h_k();
97 int pos = 0;
98 for (i=0; i<names_count; i++) {
99 symbolOop s = (symbolOop) (((char*)base) + pos);
100 s->set_mark(markOopDesc::prototype());
101 s->set_klass(sk);
102 s->set_utf8_length(lengths[i]);
103 const char* name = names[i];
104 for (int j=0; j<lengths[i]; j++) {
105 s->byte_at_put(j, name[j]);
106 }
107
108 assert(s->is_parsable(), "should be parsable here.");
109
110 sym_oops[i] = s;
111 pos += sizes[i];
112 }
113 return true;
114 }
115
116 klassOop symbolKlass::create_klass(TRAPS) {
117 symbolKlass o;
118 KlassHandle h_this_klass(THREAD, Universe::klassKlassObj());
119 KlassHandle k = base_create_klass(h_this_klass, header_size(), o.vtbl_value(), CHECK_NULL);
120 // Make sure size calculation is right
121 assert(k()->size() == align_object_size(header_size()), "wrong size for object");
122 // java_lang_Class::create_mirror(k, CHECK_NULL); // Allocate mirror
123 return k();
124 }
125
126 int symbolKlass::oop_size(oop obj) const {
127 assert(obj->is_symbol(),"must be a symbol");
128 symbolOop s = symbolOop(obj);
129 int size = s->object_size();
130 return size;
131 }
132
133 bool symbolKlass::oop_is_parsable(oop obj) const {
134 assert(obj->is_symbol(),"must be a symbol");
135 symbolOop s = symbolOop(obj);
136 return s->object_is_parsable();
137 }
138
139 void symbolKlass::oop_follow_contents(oop obj) {
140 assert (obj->is_symbol(), "object must be symbol");
141 // Performance tweak: We skip iterating over the klass pointer since we
142 // know that Universe::symbolKlassObj never moves.
143 // Note: do not follow next link here (see SymbolTable::follow_contents)
144 }
145
146 #ifndef SERIALGC
147 void symbolKlass::oop_follow_contents(ParCompactionManager* cm, oop obj) {
148 assert (obj->is_symbol(), "object must be symbol");
149 // Performance tweak: We skip iterating over the klass pointer since we
150 // know that Universe::symbolKlassObj never moves.
151 // Note: do not follow next link here (see SymbolTable::follow_contents)
152 }
153 #endif // SERIALGC
154
155 int symbolKlass::oop_oop_iterate(oop obj, OopClosure* blk) {
156 assert(obj->is_symbol(), "object must be symbol");
157 symbolOop s = symbolOop(obj);
158 // Get size before changing pointers.
159 // Don't call size() or oop_size() since that is a virtual call.
160 int size = s->object_size();
161 // Performance tweak: We skip iterating over the klass pointer since we
162 // know that Universe::symbolKlassObj never moves.
163 return size;
164 }
165
166
167 int symbolKlass::oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) {
168 assert(obj->is_symbol(), "object must be symbol");
169 symbolOop s = symbolOop(obj);
170 // Get size before changing pointers.
171 // Don't call size() or oop_size() since that is a virtual call.
172 int size = s->object_size();
173 // Performance tweak: We skip iterating over the klass pointer since we
174 // know that Universe::symbolKlassObj never moves.
175 return size;
176 }
177
178
179 int symbolKlass::oop_adjust_pointers(oop obj) {
180 assert(obj->is_symbol(), "should be symbol");
181 symbolOop s = symbolOop(obj);
182 // Get size before changing pointers.
183 // Don't call size() or oop_size() since that is a virtual call.
184 int size = s->object_size();
185 // Performance tweak: We skip iterating over the klass pointer since we
186 // know that Universe::symbolKlassObj never moves.
187 return size;
188 }
189
190
191 #ifndef SERIALGC
192 void symbolKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
193 assert(obj->is_symbol(), "should be symbol");
194 }
195
196 int symbolKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
197 assert(obj->is_symbol(), "should be symbol");
198 return symbolOop(obj)->object_size();
199 }
200
201 int symbolKlass::oop_update_pointers(ParCompactionManager* cm, oop obj,
202 HeapWord* beg_addr, HeapWord* end_addr) {
203 assert(obj->is_symbol(), "should be symbol");
204 return symbolOop(obj)->object_size();
205 }
206 #endif // SERIALGC
207
208 #ifndef PRODUCT
209 // Printing
210
211 void symbolKlass::oop_print_on(oop obj, outputStream* st) {
212 st->print("Symbol: '");
213 symbolOop(obj)->print_symbol_on(st);
214 st->print("'");
215 }
216
217 #endif //PRODUCT
218
219 void symbolKlass::oop_print_value_on(oop obj, outputStream* st) {
220 symbolOop sym = symbolOop(obj);
221 st->print("'");
222 for (int i = 0; i < sym->utf8_length(); i++) {
223 st->print("%c", sym->byte_at(i));
224 }
225 st->print("'");
226 }
227
228 const char* symbolKlass::internal_name() const {
229 return "{symbol}";
230 }