1 /*
2 * Copyright (c) 1997, 2017, 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/cpCache.hpp"
30 #include "oops/objArrayOop.hpp"
31 #include "oops/oopHandle.hpp"
32 #include "oops/symbol.hpp"
33 #include "oops/typeArrayOop.hpp"
34 #include "runtime/handles.hpp"
35 #include "utilities/align.hpp"
36 #include "utilities/bytes.hpp"
37 #include "utilities/constantTag.hpp"
38
39 // A ConstantPool is an array containing class constants as described in the
40 // class file.
41 //
42 // Most of the constant pool entries are written during class parsing, which
43 // is safe. For klass types, the constant pool entry is
44 // modified when the entry is resolved. If a klass constant pool
45 // entry is read without a lock, only the resolved state guarantees that
46 // the entry in the constant pool is a klass object and not a Symbol*.
47
48 class SymbolHashMap;
49
50 class CPSlot VALUE_OBJ_CLASS_SPEC {
51 friend class ConstantPool;
52 intptr_t _ptr;
53 enum TagBits {_pseudo_bit = 1};
54 public:
55
56 CPSlot(intptr_t ptr): _ptr(ptr) {}
57 CPSlot(Symbol* ptr, int tag_bits = 0): _ptr((intptr_t)ptr | tag_bits) {}
58
59 intptr_t value() { return _ptr; }
60 bool is_pseudo_string() { return (_ptr & _pseudo_bit) != 0; }
61
62 Symbol* get_symbol() {
63 return (Symbol*)(_ptr & ~_pseudo_bit);
64 }
65 };
66
67 // This represents a JVM_CONSTANT_Class, JVM_CONSTANT_UnresolvedClass, or
68 // JVM_CONSTANT_UnresolvedClassInError slot in the constant pool.
69 class CPKlassSlot VALUE_OBJ_CLASS_SPEC {
70 // cp->symbol_at(_name_index) gives the name of the class.
71 int _name_index;
72
73 // cp->_resolved_klasses->at(_resolved_klass_index) gives the Klass* for the class.
74 int _resolved_klass_index;
75 public:
76 enum {
77 // This is used during constant pool merging where the resolved klass index is
78 // not yet known, and will be computed at a later stage (during a call to
79 // initialize_unresolved_klasses()).
80 _temp_resolved_klass_index = 0xffff
81 };
82 CPKlassSlot(int n, int rk) {
83 _name_index = n;
84 _resolved_klass_index = rk;
85 }
86 int name_index() const {
87 return _name_index;
88 }
89 int resolved_klass_index() const {
90 assert(_resolved_klass_index != _temp_resolved_klass_index, "constant pool merging was incomplete");
91 return _resolved_klass_index;
92 }
93 };
94
95 class KlassSizeStats;
96
97 class ConstantPool : public Metadata {
98 friend class VMStructs;
99 friend class JVMCIVMStructs;
100 friend class BytecodeInterpreter; // Directly extracts a klass in the pool for fast instanceof/checkcast
101 friend class Universe; // For null constructor
102 private:
103 // If you add a new field that points to any metaspace object, you
104 // must add this field to ConstantPool::metaspace_pointers_do().
105 Array<u1>* _tags; // the tag array describing the constant pool's contents
106 ConstantPoolCache* _cache; // the cache holding interpreter runtime information
107 InstanceKlass* _pool_holder; // the corresponding class
108 Array<u2>* _operands; // for variable-sized (InvokeDynamic) nodes, usually empty
109
110 // Consider using an array of compressed klass pointers to
111 // save space on 64-bit platforms.
112 Array<Klass*>* _resolved_klasses;
113
114 enum {
115 _has_preresolution = 1, // Flags
116 _on_stack = 2,
117 _is_shared = 4
118 };
119
120 int _flags; // old fashioned bit twiddling
121 int _length; // number of elements in the array
122
123 union {
124 // set for CDS to restore resolved references
125 int _resolved_reference_length;
126 // keeps version number for redefined classes (used in backtrace)
127 int _version;
128 } _saved;
129
130 void set_tags(Array<u1>* tags) { _tags = tags; }
131 void tag_at_put(int which, jbyte t) { tags()->at_put(which, t); }
132 void release_tag_at_put(int which, jbyte t) { tags()->release_at_put(which, t); }
133
134 u1* tag_addr_at(int which) const { return tags()->adr_at(which); }
135
136 void set_operands(Array<u2>* operands) { _operands = operands; }
137
138 int flags() const { return _flags; }
139 void set_flags(int f) { _flags = f; }
140
141 private:
142 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
143
144 CPSlot slot_at(int which) const {
145 assert(is_within_bounds(which), "index out of bounds");
146 assert(!tag_at(which).is_unresolved_klass() && !tag_at(which).is_unresolved_klass_in_error(), "Corrupted constant pool");
147 // Uses volatile because the klass slot changes without a lock.
148 volatile intptr_t adr = (intptr_t)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which));
149 assert(adr != 0 || which == 0, "cp entry for klass should not be zero");
150 return CPSlot(adr);
151 }
152
153 void slot_at_put(int which, CPSlot s) const {
154 assert(is_within_bounds(which), "index out of bounds");
155 assert(s.value() != 0, "Caught something");
156 *(intptr_t*)&base()[which] = s.value();
157 }
158 intptr_t* obj_at_addr_raw(int which) const {
159 assert(is_within_bounds(which), "index out of bounds");
160 return (intptr_t*) &base()[which];
161 }
162
163 jint* int_at_addr(int which) const {
164 assert(is_within_bounds(which), "index out of bounds");
165 return (jint*) &base()[which];
166 }
167
168 jlong* long_at_addr(int which) const {
169 assert(is_within_bounds(which), "index out of bounds");
170 return (jlong*) &base()[which];
171 }
172
173 jfloat* float_at_addr(int which) const {
174 assert(is_within_bounds(which), "index out of bounds");
175 return (jfloat*) &base()[which];
176 }
177
178 jdouble* double_at_addr(int which) const {
179 assert(is_within_bounds(which), "index out of bounds");
180 return (jdouble*) &base()[which];
181 }
182
183 ConstantPool(Array<u1>* tags);
184 ConstantPool() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
185 public:
186 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
187
188 bool is_constantPool() const volatile { return true; }
189
190 Array<u1>* tags() const { return _tags; }
191 Array<u2>* operands() const { return _operands; }
192
193 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; }
194 void set_has_preresolution() {
195 assert(!is_shared(), "should never be called on shared ConstantPools");
196 _flags |= _has_preresolution;
197 }
198
199 // Redefine classes support. If a method refering to this constant pool
200 // is on the executing stack, or as a handle in vm code, this constant pool
201 // can't be removed from the set of previous versions saved in the instance
202 // class.
203 bool on_stack() const { return (_flags &_on_stack) != 0; }
204 void set_on_stack(const bool value);
205
206 // Faster than MetaspaceObj::is_shared() - used by set_on_stack()
207 bool is_shared() const { return (_flags & _is_shared) != 0; }
208
209 // Klass holding pool
210 InstanceKlass* pool_holder() const { return _pool_holder; }
211 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; }
212 InstanceKlass** pool_holder_addr() { return &_pool_holder; }
213
214 // Interpreter runtime support
215 ConstantPoolCache* cache() const { return _cache; }
216 void set_cache(ConstantPoolCache* cache){ _cache = cache; }
217
218 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
219 virtual MetaspaceObj::Type type() const { return ConstantPoolType; }
220
221 // Create object cache in the constant pool
222 void initialize_resolved_references(ClassLoaderData* loader_data,
223 const intStack& reference_map,
224 int constant_pool_map_length,
225 TRAPS);
226
227 // resolved strings, methodHandles and callsite objects from the constant pool
228 objArrayOop resolved_references() const;
229 // mapping resolved object array indexes to cp indexes and back.
230 int object_to_cp_index(int index) { return reference_map()->at(index); }
231 int cp_to_object_index(int index);
232
233 void set_resolved_klasses(Array<Klass*>* rk) { _resolved_klasses = rk; }
234 Array<Klass*>* resolved_klasses() const { return _resolved_klasses; }
235 void allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS);
236 void initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS);
237
238 // Invokedynamic indexes.
239 // They must look completely different from normal indexes.
240 // The main reason is that byte swapping is sometimes done on normal indexes.
241 // Finally, it is helpful for debugging to tell the two apart.
242 static bool is_invokedynamic_index(int i) { return (i < 0); }
243 static int decode_invokedynamic_index(int i) { assert(is_invokedynamic_index(i), ""); return ~i; }
244 static int encode_invokedynamic_index(int i) { assert(!is_invokedynamic_index(i), ""); return ~i; }
245
246
247 // The invokedynamic points at a CP cache entry. This entry points back
248 // at the original CP entry (CONSTANT_InvokeDynamic) and also (via f2) at an entry
249 // in the resolved_references array (which provides the appendix argument).
250 int invokedynamic_cp_cache_index(int index) const {
251 assert (is_invokedynamic_index(index), "should be a invokedynamic index");
252 int cache_index = decode_invokedynamic_index(index);
253 return cache_index;
254 }
255 ConstantPoolCacheEntry* invokedynamic_cp_cache_entry_at(int index) const {
256 // decode index that invokedynamic points to.
257 int cp_cache_index = invokedynamic_cp_cache_index(index);
258 return cache()->entry_at(cp_cache_index);
259 }
260
261 // Assembly code support
262 static int tags_offset_in_bytes() { return offset_of(ConstantPool, _tags); }
263 static int cache_offset_in_bytes() { return offset_of(ConstantPool, _cache); }
264 static int pool_holder_offset_in_bytes() { return offset_of(ConstantPool, _pool_holder); }
265 static int resolved_klasses_offset_in_bytes() { return offset_of(ConstantPool, _resolved_klasses); }
266
267 // Storing constants
268
269 // For temporary use while constructing constant pool
270 void klass_index_at_put(int which, int name_index) {
271 tag_at_put(which, JVM_CONSTANT_ClassIndex);
272 *int_at_addr(which) = name_index;
273 }
274
275 // Anonymous class support:
276 void klass_at_put(int class_index, int name_index, int resolved_klass_index, Klass* k, Symbol* name);
277 void klass_at_put(int class_index, Klass* k);
278
279 void unresolved_klass_at_put(int which, int name_index, int resolved_klass_index) {
280 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
281
282 assert((name_index & 0xffff0000) == 0, "must be");
283 assert((resolved_klass_index & 0xffff0000) == 0, "must be");
284 *int_at_addr(which) =
285 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
286 }
287
288 void method_handle_index_at_put(int which, int ref_kind, int ref_index) {
289 tag_at_put(which, JVM_CONSTANT_MethodHandle);
290 *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
291 }
292
293 void method_type_index_at_put(int which, int ref_index) {
294 tag_at_put(which, JVM_CONSTANT_MethodType);
295 *int_at_addr(which) = ref_index;
296 }
297
298 void invoke_dynamic_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) {
299 tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
300 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index;
301 }
302
303 void unresolved_string_at_put(int which, Symbol* s) {
304 release_tag_at_put(which, JVM_CONSTANT_String);
305 slot_at_put(which, CPSlot(s));
306 }
307
308 void int_at_put(int which, jint i) {
309 tag_at_put(which, JVM_CONSTANT_Integer);
310 *int_at_addr(which) = i;
311 }
312
313 void long_at_put(int which, jlong l) {
314 tag_at_put(which, JVM_CONSTANT_Long);
315 // *long_at_addr(which) = l;
316 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
317 }
318
319 void float_at_put(int which, jfloat f) {
320 tag_at_put(which, JVM_CONSTANT_Float);
321 *float_at_addr(which) = f;
322 }
323
324 void double_at_put(int which, jdouble d) {
325 tag_at_put(which, JVM_CONSTANT_Double);
326 // *double_at_addr(which) = d;
327 // u8 temp = *(u8*) &d;
328 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
329 }
330
331 Symbol** symbol_at_addr(int which) const {
332 assert(is_within_bounds(which), "index out of bounds");
333 return (Symbol**) &base()[which];
334 }
335
336 void symbol_at_put(int which, Symbol* s) {
337 assert(s->refcount() != 0, "should have nonzero refcount");
338 tag_at_put(which, JVM_CONSTANT_Utf8);
339 *symbol_at_addr(which) = s;
340 }
341
342 void string_at_put(int which, int obj_index, oop str);
343
344 // For temporary use while constructing constant pool
345 void string_index_at_put(int which, int string_index) {
346 tag_at_put(which, JVM_CONSTANT_StringIndex);
347 *int_at_addr(which) = string_index;
348 }
349
350 void field_at_put(int which, int class_index, int name_and_type_index) {
351 tag_at_put(which, JVM_CONSTANT_Fieldref);
352 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
353 }
354
355 void method_at_put(int which, int class_index, int name_and_type_index) {
356 tag_at_put(which, JVM_CONSTANT_Methodref);
357 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
358 }
359
360 void interface_method_at_put(int which, int class_index, int name_and_type_index) {
361 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
362 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
363 }
364
365 void name_and_type_at_put(int which, int name_index, int signature_index) {
366 tag_at_put(which, JVM_CONSTANT_NameAndType);
367 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice
368 }
369
370 // Tag query
371
372 constantTag tag_at(int which) const { return (constantTag)tags()->at_acquire(which); }
373
374 // Fetching constants
375
376 Klass* klass_at(int which, TRAPS) {
377 constantPoolHandle h_this(THREAD, this);
378 return klass_at_impl(h_this, which, true, THREAD);
379 }
380
381 // Version of klass_at that doesn't save the resolution error, called during deopt
382 Klass* klass_at_ignore_error(int which, TRAPS) {
383 constantPoolHandle h_this(THREAD, this);
384 return klass_at_impl(h_this, which, false, THREAD);
385 }
386
387 CPKlassSlot klass_slot_at(int which) const {
388 assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),
389 "Corrupted constant pool");
390 int value = *int_at_addr(which);
391 int name_index = extract_high_short_from_int(value);
392 int resolved_klass_index = extract_low_short_from_int(value);
393 return CPKlassSlot(name_index, resolved_klass_index);
394 }
395
396 Symbol* klass_name_at(int which) const; // Returns the name, w/o resolving.
397 int klass_name_index_at(int which) const {
398 return klass_slot_at(which).name_index();
399 }
400
401 Klass* resolved_klass_at(int which) const { // Used by Compiler
402 guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
403 // Must do an acquire here in case another thread resolved the klass
404 // behind our back, lest we later load stale values thru the oop.
405 CPKlassSlot kslot = klass_slot_at(which);
406 assert(tag_at(kslot.name_index()).is_symbol(), "sanity");
407
408 Klass** adr = resolved_klasses()->adr_at(kslot.resolved_klass_index());
409 return (Klass*)OrderAccess::load_ptr_acquire(adr);
410 }
411
412 // RedefineClasses() API support:
413 Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
414 void temp_unresolved_klass_at_put(int which, int name_index) {
415 // Used only during constant pool merging for class redefinition. The resolved klass index
416 // will be initialized later by a call to initialize_unresolved_klasses().
417 unresolved_klass_at_put(which, name_index, CPKlassSlot::_temp_resolved_klass_index);
418 }
419
420 jint int_at(int which) {
421 assert(tag_at(which).is_int(), "Corrupted constant pool");
422 return *int_at_addr(which);
423 }
424
425 jlong long_at(int which) {
426 assert(tag_at(which).is_long(), "Corrupted constant pool");
427 // return *long_at_addr(which);
428 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
429 return *((jlong*)&tmp);
430 }
431
432 jfloat float_at(int which) {
433 assert(tag_at(which).is_float(), "Corrupted constant pool");
434 return *float_at_addr(which);
435 }
436
437 jdouble double_at(int which) {
438 assert(tag_at(which).is_double(), "Corrupted constant pool");
439 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
440 return *((jdouble*)&tmp);
441 }
442
443 Symbol* symbol_at(int which) const {
444 assert(tag_at(which).is_utf8(), "Corrupted constant pool");
445 return *symbol_at_addr(which);
446 }
447
448 oop string_at(int which, int obj_index, TRAPS) {
449 constantPoolHandle h_this(THREAD, this);
450 return string_at_impl(h_this, which, obj_index, THREAD);
451 }
452 oop string_at(int which, TRAPS) {
453 int obj_index = cp_to_object_index(which);
454 return string_at(which, obj_index, THREAD);
455 }
456
457 // Version that can be used before string oop array is created.
458 oop uncached_string_at(int which, TRAPS);
459
460 // A "pseudo-string" is an non-string oop that has found its way into
461 // a String entry.
462 // This can happen if the user patches a live
463 // object into a CONSTANT_String entry of an anonymous class.
464 // Method oops internally created for method handles may also
465 // use pseudo-strings to link themselves to related metaobjects.
466
467 bool is_pseudo_string_at(int which) {
468 assert(tag_at(which).is_string(), "Corrupted constant pool");
469 return slot_at(which).is_pseudo_string();
470 }
471
472 oop pseudo_string_at(int which, int obj_index) {
473 assert(is_pseudo_string_at(which), "must be a pseudo-string");
474 oop s = resolved_references()->obj_at(obj_index);
475 return s;
476 }
477
478 oop pseudo_string_at(int which) {
479 assert(is_pseudo_string_at(which), "must be a pseudo-string");
480 int obj_index = cp_to_object_index(which);
481 oop s = resolved_references()->obj_at(obj_index);
482 return s;
483 }
484
485 void pseudo_string_at_put(int which, int obj_index, oop x) {
486 assert(tag_at(which).is_string(), "Corrupted constant pool");
487 Symbol* sym = unresolved_string_at(which);
488 slot_at_put(which, CPSlot(sym, CPSlot::_pseudo_bit));
489 string_at_put(which, obj_index, x); // this works just fine
490 }
491
492 // only called when we are sure a string entry is already resolved (via an
493 // earlier string_at call.
494 oop resolved_string_at(int which) {
495 assert(tag_at(which).is_string(), "Corrupted constant pool");
496 // Must do an acquire here in case another thread resolved the klass
497 // behind our back, lest we later load stale values thru the oop.
498 // we might want a volatile_obj_at in ObjArrayKlass.
499 int obj_index = cp_to_object_index(which);
500 return resolved_references()->obj_at(obj_index);
501 }
502
503 Symbol* unresolved_string_at(int which) {
504 assert(tag_at(which).is_string(), "Corrupted constant pool");
505 Symbol* sym = slot_at(which).get_symbol();
506 return sym;
507 }
508
509 // Returns an UTF8 for a CONSTANT_String entry at a given index.
510 // UTF8 char* representation was chosen to avoid conversion of
511 // java_lang_Strings at resolved entries into Symbol*s
512 // or vice versa.
513 char* string_at_noresolve(int which);
514
515 jint name_and_type_at(int which) {
516 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
517 return *int_at_addr(which);
518 }
519
520 int method_handle_ref_kind_at(int which) {
521 assert(tag_at(which).is_method_handle() ||
522 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
523 return extract_low_short_from_int(*int_at_addr(which)); // mask out unwanted ref_index bits
524 }
525 int method_handle_index_at(int which) {
526 assert(tag_at(which).is_method_handle() ||
527 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
528 return extract_high_short_from_int(*int_at_addr(which)); // shift out unwanted ref_kind bits
529 }
530 int method_type_index_at(int which) {
531 assert(tag_at(which).is_method_type() ||
532 tag_at(which).is_method_type_in_error(), "Corrupted constant pool");
533 return *int_at_addr(which);
534 }
535
536 // Derived queries:
537 Symbol* method_handle_name_ref_at(int which) {
538 int member = method_handle_index_at(which);
539 return impl_name_ref_at(member, true);
540 }
541 Symbol* method_handle_signature_ref_at(int which) {
542 int member = method_handle_index_at(which);
543 return impl_signature_ref_at(member, true);
544 }
545 int method_handle_klass_index_at(int which) {
546 int member = method_handle_index_at(which);
547 return impl_klass_ref_index_at(member, true);
548 }
549 Symbol* method_type_signature_at(int which) {
550 int sym = method_type_index_at(which);
551 return symbol_at(sym);
552 }
553
554 int invoke_dynamic_name_and_type_ref_index_at(int which) {
555 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
556 return extract_high_short_from_int(*int_at_addr(which));
557 }
558 int invoke_dynamic_bootstrap_specifier_index(int which) {
559 assert(tag_at(which).value() == JVM_CONSTANT_InvokeDynamic, "Corrupted constant pool");
560 return extract_low_short_from_int(*int_at_addr(which));
561 }
562 int invoke_dynamic_operand_base(int which) {
563 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
564 return operand_offset_at(operands(), bootstrap_specifier_index);
565 }
566 // The first part of the operands array consists of an index into the second part.
567 // Extract a 32-bit index value from the first part.
568 static int operand_offset_at(Array<u2>* operands, int bootstrap_specifier_index) {
569 int n = (bootstrap_specifier_index * 2);
570 assert(n >= 0 && n+2 <= operands->length(), "oob");
571 // The first 32-bit index points to the beginning of the second part
572 // of the operands array. Make sure this index is in the first part.
573 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
574 operands->at(1)));
575 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
576 int offset = build_int_from_shorts(operands->at(n+0),
577 operands->at(n+1));
578 // The offset itself must point into the second part of the array.
579 assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
580 return offset;
581 }
582 static void operand_offset_at_put(Array<u2>* operands, int bootstrap_specifier_index, int offset) {
583 int n = bootstrap_specifier_index * 2;
584 assert(n >= 0 && n+2 <= operands->length(), "oob");
585 operands->at_put(n+0, extract_low_short_from_int(offset));
586 operands->at_put(n+1, extract_high_short_from_int(offset));
587 }
588 static int operand_array_length(Array<u2>* operands) {
589 if (operands == NULL || operands->length() == 0) return 0;
590 int second_part = operand_offset_at(operands, 0);
591 return (second_part / 2);
592 }
593
594 #ifdef ASSERT
595 // operand tuples fit together exactly, end to end
596 static int operand_limit_at(Array<u2>* operands, int bootstrap_specifier_index) {
597 int nextidx = bootstrap_specifier_index + 1;
598 if (nextidx == operand_array_length(operands))
599 return operands->length();
600 else
601 return operand_offset_at(operands, nextidx);
602 }
603 int invoke_dynamic_operand_limit(int which) {
604 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
605 return operand_limit_at(operands(), bootstrap_specifier_index);
606 }
607 #endif //ASSERT
608
609 // layout of InvokeDynamic bootstrap method specifier (in second part of operands array):
610 enum {
611 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
612 _indy_argc_offset = 1, // u2 argc
613 _indy_argv_offset = 2 // u2 argv[argc]
614 };
615
616 // These functions are used in RedefineClasses for CP merge
617
618 int operand_offset_at(int bootstrap_specifier_index) {
619 assert(0 <= bootstrap_specifier_index &&
620 bootstrap_specifier_index < operand_array_length(operands()),
621 "Corrupted CP operands");
622 return operand_offset_at(operands(), bootstrap_specifier_index);
623 }
624 int operand_bootstrap_method_ref_index_at(int bootstrap_specifier_index) {
625 int offset = operand_offset_at(bootstrap_specifier_index);
626 return operands()->at(offset + _indy_bsm_offset);
627 }
628 int operand_argument_count_at(int bootstrap_specifier_index) {
629 int offset = operand_offset_at(bootstrap_specifier_index);
630 int argc = operands()->at(offset + _indy_argc_offset);
631 return argc;
632 }
633 int operand_argument_index_at(int bootstrap_specifier_index, int j) {
634 int offset = operand_offset_at(bootstrap_specifier_index);
635 return operands()->at(offset + _indy_argv_offset + j);
636 }
637 int operand_next_offset_at(int bootstrap_specifier_index) {
638 int offset = operand_offset_at(bootstrap_specifier_index) + _indy_argv_offset
639 + operand_argument_count_at(bootstrap_specifier_index);
640 return offset;
641 }
642 // Compare a bootsrap specifier in the operands arrays
643 bool compare_operand_to(int bootstrap_specifier_index1, const constantPoolHandle& cp2,
644 int bootstrap_specifier_index2, TRAPS);
645 // Find a bootsrap specifier in the operands array
646 int find_matching_operand(int bootstrap_specifier_index, const constantPoolHandle& search_cp,
647 int operands_cur_len, TRAPS);
648 // Resize the operands array with delta_len and delta_size
649 void resize_operands(int delta_len, int delta_size, TRAPS);
650 // Extend the operands array with the length and size of the ext_cp operands
651 void extend_operands(const constantPoolHandle& ext_cp, TRAPS);
652 // Shrink the operands array to a smaller array with new_len length
653 void shrink_operands(int new_len, TRAPS);
654
655
656 int invoke_dynamic_bootstrap_method_ref_index_at(int which) {
657 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
658 int op_base = invoke_dynamic_operand_base(which);
659 return operands()->at(op_base + _indy_bsm_offset);
660 }
661 int invoke_dynamic_argument_count_at(int which) {
662 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
663 int op_base = invoke_dynamic_operand_base(which);
664 int argc = operands()->at(op_base + _indy_argc_offset);
665 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
666 int next_offset = invoke_dynamic_operand_limit(which));
667 assert(end_offset == next_offset, "matched ending");
668 return argc;
669 }
670 int invoke_dynamic_argument_index_at(int which, int j) {
671 int op_base = invoke_dynamic_operand_base(which);
672 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
673 assert((uint)j < (uint)argc, "oob");
674 return operands()->at(op_base + _indy_argv_offset + j);
675 }
676
677 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
678 // name_and_type_ref_index_at) all expect to be passed indices obtained
679 // directly from the bytecode.
680 // If the indices are meant to refer to fields or methods, they are
681 // actually rewritten constant pool cache indices.
682 // The routine remap_instruction_operand_from_cache manages the adjustment
683 // of these values back to constant pool indices.
684
685 // There are also "uncached" versions which do not adjust the operand index; see below.
686
687 // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear.
688 // In a few cases (the verifier) there are uses before a cpcache has been built,
689 // which are handled by a dynamic check in remap_instruction_operand_from_cache.
690 // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode.
691
692 // Lookup for entries consisting of (klass_index, name_and_type index)
693 Klass* klass_ref_at(int which, TRAPS);
694 Symbol* klass_ref_at_noresolve(int which);
695 Symbol* name_ref_at(int which) { return impl_name_ref_at(which, false); }
696 Symbol* signature_ref_at(int which) { return impl_signature_ref_at(which, false); }
697
698 int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); }
699 int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); }
700
701 int remap_instruction_operand_from_cache(int operand); // operand must be biased by CPCACHE_INDEX_TAG
702
703 constantTag tag_ref_at(int cp_cache_index) { return impl_tag_ref_at(cp_cache_index, false); }
704
705 // Lookup for entries consisting of (name_index, signature_index)
706 int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt)
707 int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt)
708
709 BasicType basic_type_for_signature_at(int which) const;
710
711 // Resolve string constants (to prevent allocation during compilation)
712 void resolve_string_constants(TRAPS) {
713 constantPoolHandle h_this(THREAD, this);
714 resolve_string_constants_impl(h_this, CHECK);
715 }
716
717 // CDS support
718 void remove_unshareable_info();
719 void restore_unshareable_info(TRAPS);
720 bool resolve_class_constants(TRAPS);
721 // The ConstantPool vtable is restored by this call when the ConstantPool is
722 // in the shared archive. See patch_klass_vtables() in metaspaceShared.cpp for
723 // all the gory details. SA, dtrace and pstack helpers distinguish metadata
724 // by their vtable.
725 void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); }
726
727 private:
728 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
729 public:
730
731 // Resolve late bound constants.
732 oop resolve_constant_at(int index, TRAPS) {
733 constantPoolHandle h_this(THREAD, this);
734 return resolve_constant_at_impl(h_this, index, _no_index_sentinel, THREAD);
735 }
736
737 oop resolve_cached_constant_at(int cache_index, TRAPS) {
738 constantPoolHandle h_this(THREAD, this);
739 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, THREAD);
740 }
741
742 oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
743 constantPoolHandle h_this(THREAD, this);
744 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, THREAD);
745 }
746
747 oop resolve_bootstrap_specifier_at(int index, TRAPS) {
748 constantPoolHandle h_this(THREAD, this);
749 return resolve_bootstrap_specifier_at_impl(h_this, index, THREAD);
750 }
751
752 // Klass name matches name at offset
753 bool klass_name_at_matches(const InstanceKlass* k, int which);
754
755 // Sizing
756 int length() const { return _length; }
757 void set_length(int length) { _length = length; }
758
759 // Tells whether index is within bounds.
760 bool is_within_bounds(int index) const {
761 return 0 <= index && index < length();
762 }
763
764 // Sizing (in words)
765 static int header_size() {
766 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize;
767 }
768 static int size(int length) { return align_metadata_size(header_size() + length); }
769 int size() const { return size(length()); }
770 #if INCLUDE_SERVICES
771 void collect_statistics(KlassSizeStats *sz) const;
772 #endif
773
774 // ConstantPools should be stored in the read-only region of CDS archive.
775 static bool is_read_only_by_default() { return true; }
776
777 friend class ClassFileParser;
778 friend class SystemDictionary;
779
780 // Used by CDS. These classes need to access the private ConstantPool() constructor.
781 template <class T> friend class CppVtableTesterA;
782 template <class T> friend class CppVtableTesterB;
783 template <class T> friend class CppVtableCloner;
784
785 // Used by compiler to prevent classloading.
786 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which);
787 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
788 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
789 static bool has_method_type_at_if_loaded (const constantPoolHandle& this_cp, int which);
790 static oop method_type_at_if_loaded (const constantPoolHandle& this_cp, int which);
791 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which);
792 static Klass* klass_ref_at_if_loaded (const constantPoolHandle& this_cp, int which);
793
794 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
795 // future by other Java code. These take constant pool indices rather than
796 // constant pool cache indices as do the peer methods above.
797 Symbol* uncached_klass_ref_at_noresolve(int which);
798 Symbol* uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); }
799 Symbol* uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); }
800 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); }
801 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); }
802
803 // Sharing
804 int pre_resolve_shared_klasses(TRAPS);
805
806 // Debugging
807 const char* printable_name_at(int which) PRODUCT_RETURN0;
808
809 #ifdef ASSERT
810 enum { CPCACHE_INDEX_TAG = 0x10000 }; // helps keep CP cache indices distinct from CP indices
811 #else
812 enum { CPCACHE_INDEX_TAG = 0 }; // in product mode, this zero value is a no-op
813 #endif //ASSERT
814
815 static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) {
816 if (invokedynamic_ok && is_invokedynamic_index(raw_index))
817 return decode_invokedynamic_index(raw_index);
818 else
819 return raw_index - CPCACHE_INDEX_TAG;
820 }
821
822 private:
823
824 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); }
825 Array<u2>* reference_map() const { return (_cache == NULL) ? NULL : _cache->reference_map(); }
826 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); }
827
828 // patch JSR 292 resolved references after the class is linked.
829 void patch_resolved_references(GrowableArray<Handle>* cp_patches);
830
831 Symbol* impl_name_ref_at(int which, bool uncached);
832 Symbol* impl_signature_ref_at(int which, bool uncached);
833 int impl_klass_ref_index_at(int which, bool uncached);
834 int impl_name_and_type_ref_index_at(int which, bool uncached);
835 constantTag impl_tag_ref_at(int which, bool uncached);
836
837 // Used while constructing constant pool (only by ClassFileParser)
838 jint klass_index_at(int which) {
839 assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
840 return *int_at_addr(which);
841 }
842
843 jint string_index_at(int which) {
844 assert(tag_at(which).is_string_index(), "Corrupted constant pool");
845 return *int_at_addr(which);
846 }
847
848 // Performs the LinkResolver checks
849 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS);
850
851 // Implementation of methods that needs an exposed 'this' pointer, in order to
852 // handle GC while executing the method
853 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int which,
854 bool save_resolution_error, TRAPS);
855 static oop string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS);
856
857 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k);
858
859 // Resolve string constants (to prevent allocation during compilation)
860 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS);
861
862 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int index, int cache_index, TRAPS);
863 static oop resolve_bootstrap_specifier_at_impl(const constantPoolHandle& this_cp, int index, TRAPS);
864
865 // Exception handling
866 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS);
867 static Symbol* exception_message(const constantPoolHandle& this_cp, int which, constantTag tag, oop pending_exception);
868 static void save_and_throw_exception(const constantPoolHandle& this_cp, int which, constantTag tag, TRAPS);
869
870 public:
871 // Merging ConstantPool* support:
872 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2, TRAPS);
873 void copy_cp_to(int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS) {
874 constantPoolHandle h_this(THREAD, this);
875 copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
876 }
877 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
878 static void copy_entry_to(const constantPoolHandle& from_cp, int from_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
879 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS);
880 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp, TRAPS);
881 int version() const { return _saved._version; }
882 void set_version(int version) { _saved._version = version; }
883 void increment_and_save_version(int version) {
884 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow
885 }
886
887 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
888 int resolved_reference_length() const { return _saved._resolved_reference_length; }
889
890 // Decrease ref counts of symbols that are in the constant pool
891 // when the holder class is unloaded
892 void unreference_symbols();
893
894 // Deallocate constant pool for RedefineClasses
895 void deallocate_contents(ClassLoaderData* loader_data);
896 void release_C_heap_structures();
897
898 // JVMTI accesss - GetConstantPool, RetransformClasses, ...
899 friend class JvmtiConstantPoolReconstituter;
900
901 private:
902 jint cpool_entry_size(jint idx);
903 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
904
905 // Copy cpool bytes into byte array.
906 // Returns:
907 // int > 0, count of the raw cpool bytes that have been copied
908 // 0, OutOfMemory error
909 // -1, Internal error
910 int copy_cpool_bytes(int cpool_size,
911 SymbolHashMap* tbl,
912 unsigned char *bytes);
913
914 public:
915 // Verify
916 void verify_on(outputStream* st);
917
918 // Printing
919 void print_on(outputStream* st) const;
920 void print_value_on(outputStream* st) const;
921 void print_entry_on(int index, outputStream* st);
922
923 const char* internal_name() const { return "{constant pool}"; }
924
925 #ifndef PRODUCT
926 // Compile the world support
927 static void preload_and_initialize_all_classes(ConstantPool* constant_pool, TRAPS);
928 #endif
929 };
930
931 class SymbolHashMapEntry : public CHeapObj<mtSymbol> {
932 private:
933 unsigned int _hash; // 32-bit hash for item
934 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket
935 Symbol* _symbol; // 1-st part of the mapping: symbol => value
936 u2 _value; // 2-nd part of the mapping: symbol => value
937
938 public:
939 unsigned int hash() const { return _hash; }
940 void set_hash(unsigned int hash) { _hash = hash; }
941
942 SymbolHashMapEntry* next() const { return _next; }
943 void set_next(SymbolHashMapEntry* next) { _next = next; }
944
945 Symbol* symbol() const { return _symbol; }
946 void set_symbol(Symbol* sym) { _symbol = sym; }
947
948 u2 value() const { return _value; }
949 void set_value(u2 value) { _value = value; }
950
951 SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
952 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
953
954 }; // End SymbolHashMapEntry class
955
956
957 class SymbolHashMapBucket : public CHeapObj<mtSymbol> {
958
959 private:
960 SymbolHashMapEntry* _entry;
961
962 public:
963 SymbolHashMapEntry* entry() const { return _entry; }
964 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
965 void clear() { _entry = NULL; }
966
967 }; // End SymbolHashMapBucket class
968
969
970 class SymbolHashMap: public CHeapObj<mtSymbol> {
971
972 private:
973 // Default number of entries in the table
974 enum SymbolHashMap_Constants {
975 _Def_HashMap_Size = 256
976 };
977
978 int _table_size;
979 SymbolHashMapBucket* _buckets;
980
981 void initialize_table(int table_size) {
982 _table_size = table_size;
983 _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size, mtSymbol);
984 for (int index = 0; index < table_size; index++) {
985 _buckets[index].clear();
986 }
987 }
988
989 public:
990
991 int table_size() const { return _table_size; }
992
993 SymbolHashMap() { initialize_table(_Def_HashMap_Size); }
994 SymbolHashMap(int table_size) { initialize_table(table_size); }
995
996 // hash P(31) from Kernighan & Ritchie
997 static unsigned int compute_hash(const char* str, int len) {
998 unsigned int hash = 0;
999 while (len-- > 0) {
1000 hash = 31*hash + (unsigned) *str;
1001 str++;
1002 }
1003 return hash;
1004 }
1005
1006 SymbolHashMapEntry* bucket(int i) {
1007 return _buckets[i].entry();
1008 }
1009
1010 void add_entry(Symbol* sym, u2 value);
1011 SymbolHashMapEntry* find_entry(Symbol* sym);
1012
1013 u2 symbol_to_value(Symbol* sym) {
1014 SymbolHashMapEntry *entry = find_entry(sym);
1015 return (entry == NULL) ? 0 : entry->value();
1016 }
1017
1018 ~SymbolHashMap() {
1019 SymbolHashMapEntry* next;
1020 for (int i = 0; i < _table_size; i++) {
1021 for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
1022 next = cur->next();
1023 delete(cur);
1024 }
1025 }
1026 delete _buckets;
1027 }
1028 }; // End SymbolHashMap class
1029
1030 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP