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 #ifndef SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP
26 #define SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP
27
28 #include "oops/arrayOop.hpp"
29 #include "oops/cpCacheOop.hpp"
30 #include "oops/symbol.hpp"
31 #include "oops/typeArrayOop.hpp"
32 #include "utilities/constantTag.hpp"
33 #ifdef TARGET_ARCH_x86
34 # include "bytes_x86.hpp"
35 #endif
36 #ifdef TARGET_ARCH_sparc
37 # include "bytes_sparc.hpp"
38 #endif
39 #ifdef TARGET_ARCH_zero
40 # include "bytes_zero.hpp"
41 #endif
42 #ifdef TARGET_ARCH_arm
43 # include "bytes_arm.hpp"
44 #endif
45 #ifdef TARGET_ARCH_ppc
46 # include "bytes_ppc.hpp"
47 #endif
48
49 // A constantPool is an array containing class constants as described in the
50 // class file.
51 //
52 // Most of the constant pool entries are written during class parsing, which
53 // is safe. For klass and string types, the constant pool entry is
54 // modified when the entry is resolved. If a klass or string constant pool
55 // entry is read without a lock, only the resolved state guarantees that
56 // the entry in the constant pool is a klass or String object and
57 // not a Symbol*.
58
59 class SymbolHashMap;
60
61 class CPSlot VALUE_OBJ_CLASS_SPEC {
62 intptr_t _ptr;
63 public:
64 CPSlot(intptr_t ptr): _ptr(ptr) {}
65 CPSlot(void* ptr): _ptr((intptr_t)ptr) {}
66 CPSlot(oop ptr): _ptr((intptr_t)ptr) {}
67 CPSlot(Symbol* ptr): _ptr((intptr_t)ptr | 1) {}
68
69 intptr_t value() { return _ptr; }
70 bool is_oop() { return (_ptr & 1) == 0; }
71 bool is_metadata() { return (_ptr & 1) == 1; }
72
73 oop get_oop() {
74 assert(is_oop(), "bad call");
75 return oop(_ptr);
76 }
77 Symbol* get_symbol() {
78 assert(is_metadata(), "bad call");
79 return (Symbol*)(_ptr & ~1);
80 }
81 };
82
83 class constantPoolOopDesc : public oopDesc {
84 friend class VMStructs;
85 friend class BytecodeInterpreter; // Directly extracts an oop in the pool for fast instanceof/checkcast
86 private:
87 typeArrayOop _tags; // the tag array describing the constant pool's contents
88 constantPoolCacheOop _cache; // the cache holding interpreter runtime information
89 klassOop _pool_holder; // the corresponding class
90 typeArrayOop _operands; // for variable-sized (InvokeDynamic) nodes, usually empty
91 int _flags; // a few header bits to describe contents for GC
92 int _length; // number of elements in the array
93 volatile bool _is_conc_safe; // if true, safe for concurrent
94 // GC processing
95 // only set to non-zero if constant pool is merged by RedefineClasses
96 int _orig_length;
97
98 void set_tags(typeArrayOop tags) { oop_store_without_check((oop*)&_tags, tags); }
99 void tag_at_put(int which, jbyte t) { tags()->byte_at_put(which, t); }
100 void release_tag_at_put(int which, jbyte t) { tags()->release_byte_at_put(which, t); }
101
102 void set_operands(typeArrayOop operands) { oop_store_without_check((oop*)&_operands, operands); }
103
104 enum FlagBit {
105 FB_has_invokedynamic = 1,
106 FB_has_pseudo_string = 2
107 };
108
109 int flags() const { return _flags; }
110 void set_flags(int f) { _flags = f; }
111 bool flag_at(FlagBit fb) const { return (_flags & (1 << (int)fb)) != 0; }
112 void set_flag_at(FlagBit fb);
113 // no clear_flag_at function; they only increase
114
115 private:
116 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(constantPoolOopDesc)); }
117 oop* tags_addr() { return (oop*)&_tags; }
118 oop* cache_addr() { return (oop*)&_cache; }
119 oop* operands_addr() { return (oop*)&_operands; }
120
121 CPSlot slot_at(int which) {
122 assert(is_within_bounds(which), "index out of bounds");
123 // There's a transitional value of zero when converting from
124 // Symbol->0->Klass for G1 when resolving classes and strings.
125 // wait for the value to be non-zero (this is temporary)
126 volatile intptr_t adr = (intptr_t)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which));
127 if (adr == 0 && which != 0) {
128 constantTag t = tag_at(which);
129 if (t.is_unresolved_klass() || t.is_klass() ||
130 t.is_unresolved_string() || t.is_string()) {
131 while ((adr = (intptr_t)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))) == 0);
132 }
133 }
134 return CPSlot(adr);
135 }
136
137 void slot_at_put(int which, CPSlot s) const {
138 assert(is_within_bounds(which), "index out of bounds");
139 *(intptr_t*)&base()[which] = s.value();
140 }
141 oop* obj_at_addr_raw(int which) const {
142 assert(is_within_bounds(which), "index out of bounds");
143 return (oop*) &base()[which];
144 }
145
146 void obj_at_put_without_check(int which, oop o) {
147 assert(is_within_bounds(which), "index out of bounds");
148 oop_store_without_check((volatile oop *)obj_at_addr_raw(which), o);
149 }
150
151 void obj_at_put(int which, oop o) const {
152 assert(is_within_bounds(which), "index out of bounds");
153 oop_store((volatile oop*)obj_at_addr_raw(which), o);
154 }
155
156 jint* int_at_addr(int which) const {
157 assert(is_within_bounds(which), "index out of bounds");
158 return (jint*) &base()[which];
159 }
160
161 jlong* long_at_addr(int which) const {
162 assert(is_within_bounds(which), "index out of bounds");
163 return (jlong*) &base()[which];
164 }
165
166 jfloat* float_at_addr(int which) const {
167 assert(is_within_bounds(which), "index out of bounds");
168 return (jfloat*) &base()[which];
169 }
170
171 jdouble* double_at_addr(int which) const {
172 assert(is_within_bounds(which), "index out of bounds");
173 return (jdouble*) &base()[which];
174 }
175
176 public:
177 typeArrayOop tags() const { return _tags; }
178 typeArrayOop operands() const { return _operands; }
179
180 bool has_pseudo_string() const { return flag_at(FB_has_pseudo_string); }
181 bool has_invokedynamic() const { return flag_at(FB_has_invokedynamic); }
182 void set_pseudo_string() { set_flag_at(FB_has_pseudo_string); }
183 void set_invokedynamic() { set_flag_at(FB_has_invokedynamic); }
184
185 // Klass holding pool
186 klassOop pool_holder() const { return _pool_holder; }
187 void set_pool_holder(klassOop k) { oop_store_without_check((oop*)&_pool_holder, (oop) k); }
188 oop* pool_holder_addr() { return (oop*)&_pool_holder; }
189
190 // Interpreter runtime support
191 constantPoolCacheOop cache() const { return _cache; }
192 void set_cache(constantPoolCacheOop cache){ oop_store((oop*)&_cache, cache); }
193
194 // Assembly code support
195 static int tags_offset_in_bytes() { return offset_of(constantPoolOopDesc, _tags); }
196 static int cache_offset_in_bytes() { return offset_of(constantPoolOopDesc, _cache); }
197 static int operands_offset_in_bytes() { return offset_of(constantPoolOopDesc, _operands); }
198 static int pool_holder_offset_in_bytes() { return offset_of(constantPoolOopDesc, _pool_holder); }
199
200 // Storing constants
201
202 void klass_at_put(int which, klassOop k) {
203 // Overwrite the old index with a GC friendly value so
204 // that if G1 looks during the transition during oop_store it won't
205 // assert the symbol is not an oop.
206 *obj_at_addr_raw(which) = NULL;
207 assert(k != NULL, "resolved class shouldn't be null");
208 obj_at_put_without_check(which, k);
209 // The interpreter assumes when the tag is stored, the klass is resolved
210 // and the klassOop is a klass rather than a Symbol*, so we need
211 // hardware store ordering here.
212 release_tag_at_put(which, JVM_CONSTANT_Class);
213 if (UseConcMarkSweepGC) {
214 // In case the earlier card-mark was consumed by a concurrent
215 // marking thread before the tag was updated, redirty the card.
216 obj_at_put_without_check(which, k);
217 }
218 }
219
220 // For temporary use while constructing constant pool
221 void klass_index_at_put(int which, int name_index) {
222 tag_at_put(which, JVM_CONSTANT_ClassIndex);
223 *int_at_addr(which) = name_index;
224 }
225
226 // Temporary until actual use
227 void unresolved_klass_at_put(int which, Symbol* s) {
228 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
229 slot_at_put(which, s);
230 }
231
232 void method_handle_index_at_put(int which, int ref_kind, int ref_index) {
233 tag_at_put(which, JVM_CONSTANT_MethodHandle);
234 *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
235 }
236
237 void method_type_index_at_put(int which, int ref_index) {
238 tag_at_put(which, JVM_CONSTANT_MethodType);
239 *int_at_addr(which) = ref_index;
240 }
241
242 void invoke_dynamic_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) {
243 tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
244 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index;
245 }
246
247 void invoke_dynamic_trans_at_put(int which, int bootstrap_method_index, int name_and_type_index) {
248 tag_at_put(which, JVM_CONSTANT_InvokeDynamicTrans);
249 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_method_index;
250 assert(AllowTransitionalJSR292, "");
251 }
252
253 // Temporary until actual use
254 void unresolved_string_at_put(int which, Symbol* s) {
255 release_tag_at_put(which, JVM_CONSTANT_UnresolvedString);
256 slot_at_put(which, s);
257 }
258
259 void int_at_put(int which, jint i) {
260 tag_at_put(which, JVM_CONSTANT_Integer);
261 *int_at_addr(which) = i;
262 }
263
264 void long_at_put(int which, jlong l) {
265 tag_at_put(which, JVM_CONSTANT_Long);
266 // *long_at_addr(which) = l;
267 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
268 }
269
270 void float_at_put(int which, jfloat f) {
271 tag_at_put(which, JVM_CONSTANT_Float);
272 *float_at_addr(which) = f;
273 }
274
275 void double_at_put(int which, jdouble d) {
276 tag_at_put(which, JVM_CONSTANT_Double);
277 // *double_at_addr(which) = d;
278 // u8 temp = *(u8*) &d;
279 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
280 }
281
282 Symbol** symbol_at_addr(int which) const {
283 assert(is_within_bounds(which), "index out of bounds");
284 return (Symbol**) &base()[which];
285 }
286
287 void symbol_at_put(int which, Symbol* s) {
288 assert(s->refcount() != 0, "should have nonzero refcount");
289 tag_at_put(which, JVM_CONSTANT_Utf8);
290 slot_at_put(which, s);
291 }
292
293 void string_at_put(int which, oop str) {
294 // Overwrite the old index with a GC friendly value so
295 // that if G1 looks during the transition during oop_store it won't
296 // assert the symbol is not an oop.
297 *obj_at_addr_raw(which) = NULL;
298 assert(str != NULL, "resolved string shouldn't be null");
299 obj_at_put(which, str);
300 release_tag_at_put(which, JVM_CONSTANT_String);
301 if (UseConcMarkSweepGC) {
302 // In case the earlier card-mark was consumed by a concurrent
303 // marking thread before the tag was updated, redirty the card.
304 obj_at_put_without_check(which, str);
305 }
306 }
307
308 void object_at_put(int which, oop str) {
309 obj_at_put(which, str);
310 release_tag_at_put(which, JVM_CONSTANT_Object);
311 if (UseConcMarkSweepGC) {
312 // In case the earlier card-mark was consumed by a concurrent
313 // marking thread before the tag was updated, redirty the card.
314 obj_at_put_without_check(which, str);
315 }
316 }
317
318 // For temporary use while constructing constant pool
319 void string_index_at_put(int which, int string_index) {
320 tag_at_put(which, JVM_CONSTANT_StringIndex);
321 *int_at_addr(which) = string_index;
322 }
323
324 void field_at_put(int which, int class_index, int name_and_type_index) {
325 tag_at_put(which, JVM_CONSTANT_Fieldref);
326 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
327 }
328
329 void method_at_put(int which, int class_index, int name_and_type_index) {
330 tag_at_put(which, JVM_CONSTANT_Methodref);
331 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
332 }
333
334 void interface_method_at_put(int which, int class_index, int name_and_type_index) {
335 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
336 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
337 }
338
339 void name_and_type_at_put(int which, int name_index, int signature_index) {
340 tag_at_put(which, JVM_CONSTANT_NameAndType);
341 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice
342 }
343
344 // Tag query
345
346 constantTag tag_at(int which) const { return (constantTag)tags()->byte_at_acquire(which); }
347
348 // Whether the entry is a pointer that must be GC'd.
349 bool is_pointer_entry(int which) {
350 constantTag tag = tag_at(which);
351 return tag.is_klass() ||
352 tag.is_string() ||
353 tag.is_object();
354 }
355
356 // Whether the entry points to an object for ldc (resolved or not)
357 bool is_object_entry(int which) {
358 constantTag tag = tag_at(which);
359 return is_pointer_entry(which) ||
360 tag.is_unresolved_klass() ||
361 tag.is_unresolved_string() ||
362 tag.is_symbol();
363 }
364
365 // Fetching constants
366
367 klassOop klass_at(int which, TRAPS) {
368 constantPoolHandle h_this(THREAD, this);
369 return klass_at_impl(h_this, which, CHECK_NULL);
370 }
371
372 Symbol* klass_name_at(int which); // Returns the name, w/o resolving.
373
374 klassOop resolved_klass_at(int which) { // Used by Compiler
375 guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
376 // Must do an acquire here in case another thread resolved the klass
377 // behind our back, lest we later load stale values thru the oop.
378 return klassOop(CPSlot(OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_oop());
379 }
380
381 // This method should only be used with a cpool lock or during parsing or gc
382 Symbol* unresolved_klass_at(int which) { // Temporary until actual use
383 Symbol* s = CPSlot(OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_symbol();
384 // check that the klass is still unresolved.
385 assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool");
386 return s;
387 }
388
389 // RedefineClasses() API support:
390 Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
391
392 jint int_at(int which) {
393 assert(tag_at(which).is_int(), "Corrupted constant pool");
394 return *int_at_addr(which);
395 }
396
397 jlong long_at(int which) {
398 assert(tag_at(which).is_long(), "Corrupted constant pool");
399 // return *long_at_addr(which);
400 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
401 return *((jlong*)&tmp);
402 }
403
404 jfloat float_at(int which) {
405 assert(tag_at(which).is_float(), "Corrupted constant pool");
406 return *float_at_addr(which);
407 }
408
409 jdouble double_at(int which) {
410 assert(tag_at(which).is_double(), "Corrupted constant pool");
411 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
412 return *((jdouble*)&tmp);
413 }
414
415 Symbol* symbol_at(int which) {
416 assert(tag_at(which).is_utf8(), "Corrupted constant pool");
417 return slot_at(which).get_symbol();
418 }
419
420 oop string_at(int which, TRAPS) {
421 constantPoolHandle h_this(THREAD, this);
422 return string_at_impl(h_this, which, CHECK_NULL);
423 }
424
425 oop object_at(int which) {
426 assert(tag_at(which).is_object(), "Corrupted constant pool");
427 return slot_at(which).get_oop();
428 }
429
430 // A "pseudo-string" is an non-string oop that has found is way into
431 // a String entry.
432 // Under AnonymousClasses this can happen if the user patches a live
433 // object into a CONSTANT_String entry of an anonymous class.
434 // Method oops internally created for method handles may also
435 // use pseudo-strings to link themselves to related metaobjects.
436
437 bool is_pseudo_string_at(int which);
438
439 oop pseudo_string_at(int which) {
440 assert(tag_at(which).is_string(), "Corrupted constant pool");
441 return slot_at(which).get_oop();
442 }
443
444 void pseudo_string_at_put(int which, oop x) {
445 assert(AnonymousClasses, "");
446 set_pseudo_string(); // mark header
447 assert(tag_at(which).is_string() || tag_at(which).is_unresolved_string(), "Corrupted constant pool");
448 string_at_put(which, x); // this works just fine
449 }
450
451 // only called when we are sure a string entry is already resolved (via an
452 // earlier string_at call.
453 oop resolved_string_at(int which) {
454 assert(tag_at(which).is_string(), "Corrupted constant pool");
455 // Must do an acquire here in case another thread resolved the klass
456 // behind our back, lest we later load stale values thru the oop.
457 return CPSlot(OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_oop();
458 }
459
460 // This method should only be used with a cpool lock or during parsing or gc
461 Symbol* unresolved_string_at(int which) { // Temporary until actual use
462 Symbol* s = CPSlot(OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_symbol();
463 // check that the string is still unresolved.
464 assert(tag_at(which).is_unresolved_string(), "Corrupted constant pool");
465 return s;
466 }
467
468 // Returns an UTF8 for a CONSTANT_String entry at a given index.
469 // UTF8 char* representation was chosen to avoid conversion of
470 // java_lang_Strings at resolved entries into Symbol*s
471 // or vice versa.
472 // Caller is responsible for checking for pseudo-strings.
473 char* string_at_noresolve(int which);
474
475 jint name_and_type_at(int which) {
476 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
477 return *int_at_addr(which);
478 }
479
480 int method_handle_ref_kind_at(int which) {
481 assert(tag_at(which).is_method_handle(), "Corrupted constant pool");
482 return extract_low_short_from_int(*int_at_addr(which)); // mask out unwanted ref_index bits
483 }
484 int method_handle_index_at(int which) {
485 assert(tag_at(which).is_method_handle(), "Corrupted constant pool");
486 return extract_high_short_from_int(*int_at_addr(which)); // shift out unwanted ref_kind bits
487 }
488 int method_type_index_at(int which) {
489 assert(tag_at(which).is_method_type(), "Corrupted constant pool");
490 return *int_at_addr(which);
491 }
492 // Derived queries:
493 Symbol* method_handle_name_ref_at(int which) {
494 int member = method_handle_index_at(which);
495 return impl_name_ref_at(member, true);
496 }
497 Symbol* method_handle_signature_ref_at(int which) {
498 int member = method_handle_index_at(which);
499 return impl_signature_ref_at(member, true);
500 }
501 int method_handle_klass_index_at(int which) {
502 int member = method_handle_index_at(which);
503 return impl_klass_ref_index_at(member, true);
504 }
505 Symbol* method_type_signature_at(int which) {
506 int sym = method_type_index_at(which);
507 return symbol_at(sym);
508 }
509
510 int invoke_dynamic_name_and_type_ref_index_at(int which) {
511 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
512 return extract_high_short_from_int(*int_at_addr(which));
513 }
514 int invoke_dynamic_bootstrap_specifier_index(int which) {
515 assert(tag_at(which).value() == JVM_CONSTANT_InvokeDynamic, "Corrupted constant pool");
516 return extract_low_short_from_int(*int_at_addr(which));
517 }
518 int invoke_dynamic_operand_base(int which) {
519 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
520 return operand_offset_at(operands(), bootstrap_specifier_index);
521 }
522 // The first part of the operands array consists of an index into the second part.
523 // Extract a 32-bit index value from the first part.
524 static int operand_offset_at(typeArrayOop operands, int bootstrap_specifier_index) {
525 int n = (bootstrap_specifier_index * 2);
526 assert(n >= 0 && n+2 <= operands->length(), "oob");
527 // The first 32-bit index points to the beginning of the second part
528 // of the operands array. Make sure this index is in the first part.
529 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->short_at(0),
530 operands->short_at(1)));
531 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
532 int offset = build_int_from_shorts(operands->short_at(n+0),
533 operands->short_at(n+1));
534 // The offset itself must point into the second part of the array.
535 assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
536 return offset;
537 }
538 static void operand_offset_at_put(typeArrayOop operands, int bootstrap_specifier_index, int offset) {
539 int n = bootstrap_specifier_index * 2;
540 assert(n >= 0 && n+2 <= operands->length(), "oob");
541 operands->short_at_put(n+0, extract_low_short_from_int(offset));
542 operands->short_at_put(n+1, extract_high_short_from_int(offset));
543 }
544 static int operand_array_length(typeArrayOop operands) {
545 if (operands == NULL || operands->length() == 0) return 0;
546 int second_part = operand_offset_at(operands, 0);
547 return (second_part / 2);
548 }
549
550 #ifdef ASSERT
551 // operand tuples fit together exactly, end to end
552 static int operand_limit_at(typeArrayOop operands, int bootstrap_specifier_index) {
553 int nextidx = bootstrap_specifier_index + 1;
554 if (nextidx == operand_array_length(operands))
555 return operands->length();
556 else
557 return operand_offset_at(operands, nextidx);
558 }
559 int invoke_dynamic_operand_limit(int which) {
560 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
561 return operand_limit_at(operands(), bootstrap_specifier_index);
562 }
563 #endif //ASSERT
564
565 // layout of InvokeDynamic bootstrap method specifier (in second part of operands array):
566 enum {
567 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
568 _indy_argc_offset = 1, // u2 argc
569 _indy_argv_offset = 2 // u2 argv[argc]
570 };
571 int invoke_dynamic_bootstrap_method_ref_index_at(int which) {
572 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
573 if (tag_at(which).value() == JVM_CONSTANT_InvokeDynamicTrans)
574 return extract_low_short_from_int(*int_at_addr(which));
575 int op_base = invoke_dynamic_operand_base(which);
576 return operands()->short_at(op_base + _indy_bsm_offset);
577 }
578 int invoke_dynamic_argument_count_at(int which) {
579 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
580 if (tag_at(which).value() == JVM_CONSTANT_InvokeDynamicTrans)
581 return 0;
582 int op_base = invoke_dynamic_operand_base(which);
583 int argc = operands()->short_at(op_base + _indy_argc_offset);
584 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
585 int next_offset = invoke_dynamic_operand_limit(which));
586 assert(end_offset == next_offset, "matched ending");
587 return argc;
588 }
589 int invoke_dynamic_argument_index_at(int which, int j) {
590 int op_base = invoke_dynamic_operand_base(which);
591 DEBUG_ONLY(int argc = operands()->short_at(op_base + _indy_argc_offset));
592 assert((uint)j < (uint)argc, "oob");
593 return operands()->short_at(op_base + _indy_argv_offset + j);
594 }
595
596 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
597 // name_and_type_ref_index_at) all expect to be passed indices obtained
598 // directly from the bytecode.
599 // If the indices are meant to refer to fields or methods, they are
600 // actually rewritten constant pool cache indices.
601 // The routine remap_instruction_operand_from_cache manages the adjustment
602 // of these values back to constant pool indices.
603
604 // There are also "uncached" versions which do not adjust the operand index; see below.
605
606 // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear.
607 // In a few cases (the verifier) there are uses before a cpcache has been built,
608 // which are handled by a dynamic check in remap_instruction_operand_from_cache.
609 // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode.
610
611 // Lookup for entries consisting of (klass_index, name_and_type index)
612 klassOop klass_ref_at(int which, TRAPS);
613 Symbol* klass_ref_at_noresolve(int which);
614 Symbol* name_ref_at(int which) { return impl_name_ref_at(which, false); }
615 Symbol* signature_ref_at(int which) { return impl_signature_ref_at(which, false); }
616
617 int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); }
618 int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); }
619
620 // Lookup for entries consisting of (name_index, signature_index)
621 int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt)
622 int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt)
623
624 BasicType basic_type_for_signature_at(int which);
625
626 // Resolve string constants (to prevent allocation during compilation)
627 void resolve_string_constants(TRAPS) {
628 constantPoolHandle h_this(THREAD, this);
629 resolve_string_constants_impl(h_this, CHECK);
630 }
631
632 private:
633 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
634 public:
635
636 // Resolve late bound constants.
637 oop resolve_constant_at(int index, TRAPS) {
638 constantPoolHandle h_this(THREAD, this);
639 return resolve_constant_at_impl(h_this, index, _no_index_sentinel, THREAD);
640 }
641
642 oop resolve_cached_constant_at(int cache_index, TRAPS) {
643 constantPoolHandle h_this(THREAD, this);
644 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, THREAD);
645 }
646
647 oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
648 constantPoolHandle h_this(THREAD, this);
649 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, THREAD);
650 }
651
652 // Klass name matches name at offset
653 bool klass_name_at_matches(instanceKlassHandle k, int which);
654
655 // Sizing
656 int length() const { return _length; }
657 void set_length(int length) { _length = length; }
658
659 // Tells whether index is within bounds.
660 bool is_within_bounds(int index) const {
661 return 0 <= index && index < length();
662 }
663
664 static int header_size() { return sizeof(constantPoolOopDesc)/HeapWordSize; }
665 static int object_size(int length) { return align_object_size(header_size() + length); }
666 int object_size() { return object_size(length()); }
667
668 bool is_conc_safe() { return _is_conc_safe; }
669 void set_is_conc_safe(bool v) { _is_conc_safe = v; }
670
671 friend class constantPoolKlass;
672 friend class ClassFileParser;
673 friend class SystemDictionary;
674
675 // Used by compiler to prevent classloading.
676 static klassOop klass_at_if_loaded (constantPoolHandle this_oop, int which);
677 static klassOop klass_ref_at_if_loaded (constantPoolHandle this_oop, int which);
678 // Same as above - but does LinkResolving.
679 static klassOop klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int which, TRAPS);
680
681 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
682 // future by other Java code. These take constant pool indices rather than
683 // constant pool cache indices as do the peer methods above.
684 Symbol* uncached_klass_ref_at_noresolve(int which);
685 Symbol* uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); }
686 Symbol* uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); }
687 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); }
688 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); }
689
690 // Sharing
691 int pre_resolve_shared_klasses(TRAPS);
692 void shared_symbols_iterate(SymbolClosure* closure0);
693 void shared_tags_iterate(OopClosure* closure0);
694 void shared_strings_iterate(OopClosure* closure0);
695
696 // Debugging
697 const char* printable_name_at(int which) PRODUCT_RETURN0;
698
699 #ifdef ASSERT
700 enum { CPCACHE_INDEX_TAG = 0x10000 }; // helps keep CP cache indices distinct from CP indices
701 #else
702 enum { CPCACHE_INDEX_TAG = 0 }; // in product mode, this zero value is a no-op
703 #endif //ASSERT
704
705 private:
706
707 Symbol* impl_name_ref_at(int which, bool uncached);
708 Symbol* impl_signature_ref_at(int which, bool uncached);
709 int impl_klass_ref_index_at(int which, bool uncached);
710 int impl_name_and_type_ref_index_at(int which, bool uncached);
711
712 int remap_instruction_operand_from_cache(int operand); // operand must be biased by CPCACHE_INDEX_TAG
713
714 // Used while constructing constant pool (only by ClassFileParser)
715 jint klass_index_at(int which) {
716 assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
717 return *int_at_addr(which);
718 }
719
720 jint string_index_at(int which) {
721 assert(tag_at(which).is_string_index(), "Corrupted constant pool");
722 return *int_at_addr(which);
723 }
724
725 // Performs the LinkResolver checks
726 static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS);
727
728 // Implementation of methods that needs an exposed 'this' pointer, in order to
729 // handle GC while executing the method
730 static klassOop klass_at_impl(constantPoolHandle this_oop, int which, TRAPS);
731 static oop string_at_impl(constantPoolHandle this_oop, int which, TRAPS);
732
733 // Resolve string constants (to prevent allocation during compilation)
734 static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS);
735
736 static oop resolve_constant_at_impl(constantPoolHandle this_oop, int index, int cache_index, TRAPS);
737
738 public:
739 // Merging constantPoolOop support:
740 bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS);
741 void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS) {
742 constantPoolHandle h_this(THREAD, this);
743 copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
744 }
745 static void copy_cp_to_impl(constantPoolHandle from_cp, int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS);
746 static void copy_entry_to(constantPoolHandle from_cp, int from_i, constantPoolHandle to_cp, int to_i, TRAPS);
747 int find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS);
748 int orig_length() const { return _orig_length; }
749 void set_orig_length(int orig_length) { _orig_length = orig_length; }
750
751 // Decrease ref counts of symbols that are in the constant pool
752 // when the holder class is unloaded
753 void unreference_symbols();
754
755 // JVMTI accesss - GetConstantPool, RetransformClasses, ...
756 friend class JvmtiConstantPoolReconstituter;
757
758 private:
759 jint cpool_entry_size(jint idx);
760 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
761
762 // Copy cpool bytes into byte array.
763 // Returns:
764 // int > 0, count of the raw cpool bytes that have been copied
765 // 0, OutOfMemory error
766 // -1, Internal error
767 int copy_cpool_bytes(int cpool_size,
768 SymbolHashMap* tbl,
769 unsigned char *bytes);
770 };
771
772 class SymbolHashMapEntry : public CHeapObj {
773 private:
774 unsigned int _hash; // 32-bit hash for item
775 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket
776 Symbol* _symbol; // 1-st part of the mapping: symbol => value
777 u2 _value; // 2-nd part of the mapping: symbol => value
778
779 public:
780 unsigned int hash() const { return _hash; }
781 void set_hash(unsigned int hash) { _hash = hash; }
782
783 SymbolHashMapEntry* next() const { return _next; }
784 void set_next(SymbolHashMapEntry* next) { _next = next; }
785
786 Symbol* symbol() const { return _symbol; }
787 void set_symbol(Symbol* sym) { _symbol = sym; }
788
789 u2 value() const { return _value; }
790 void set_value(u2 value) { _value = value; }
791
792 SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
793 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
794
795 }; // End SymbolHashMapEntry class
796
797
798 class SymbolHashMapBucket : public CHeapObj {
799
800 private:
801 SymbolHashMapEntry* _entry;
802
803 public:
804 SymbolHashMapEntry* entry() const { return _entry; }
805 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
806 void clear() { _entry = NULL; }
807
808 }; // End SymbolHashMapBucket class
809
810
811 class SymbolHashMap: public CHeapObj {
812
813 private:
814 // Default number of entries in the table
815 enum SymbolHashMap_Constants {
816 _Def_HashMap_Size = 256
817 };
818
819 int _table_size;
820 SymbolHashMapBucket* _buckets;
821
822 void initialize_table(int table_size) {
823 _table_size = table_size;
824 _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size);
825 for (int index = 0; index < table_size; index++) {
826 _buckets[index].clear();
827 }
828 }
829
830 public:
831
832 int table_size() const { return _table_size; }
833
834 SymbolHashMap() { initialize_table(_Def_HashMap_Size); }
835 SymbolHashMap(int table_size) { initialize_table(table_size); }
836
837 // hash P(31) from Kernighan & Ritchie
838 static unsigned int compute_hash(const char* str, int len) {
839 unsigned int hash = 0;
840 while (len-- > 0) {
841 hash = 31*hash + (unsigned) *str;
842 str++;
843 }
844 return hash;
845 }
846
847 SymbolHashMapEntry* bucket(int i) {
848 return _buckets[i].entry();
849 }
850
851 void add_entry(Symbol* sym, u2 value);
852 SymbolHashMapEntry* find_entry(Symbol* sym);
853
854 u2 symbol_to_value(Symbol* sym) {
855 SymbolHashMapEntry *entry = find_entry(sym);
856 return (entry == NULL) ? 0 : entry->value();
857 }
858
859 ~SymbolHashMap() {
860 SymbolHashMapEntry* next;
861 for (int i = 0; i < _table_size; i++) {
862 for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
863 next = cur->next();
864 delete(cur);
865 }
866 }
867 delete _buckets;
868 }
869 }; // End SymbolHashMap class
870
871 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP