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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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/symbol.hpp"
32 #include "oops/typeArrayOop.hpp"
33 #include "runtime/handles.hpp"
34 #include "utilities/align.hpp"
35 #include "utilities/bytes.hpp"
36 #include "utilities/constantTag.hpp"
37
38 // A ConstantPool is an array containing class constants as described in the
39 // class file.
40 //
41 // Most of the constant pool entries are written during class parsing, which
42 // is safe. For klass types, the constant pool entry is
43 // modified when the entry is resolved. If a klass constant pool
44 // entry is read without a lock, only the resolved state guarantees that
45 // the entry in the constant pool is a klass object and not a Symbol*.
46
47 class SymbolHashMap;
48
49 class CPSlot VALUE_OBJ_CLASS_SPEC {
50 friend class ConstantPool;
51 intptr_t _ptr;
52 enum TagBits {_pseudo_bit = 1};
53 public:
54
55 CPSlot(intptr_t ptr): _ptr(ptr) {}
56 CPSlot(Symbol* ptr, int tag_bits = 0): _ptr((intptr_t)ptr | tag_bits) {}
57
58 intptr_t value() { return _ptr; }
59 bool is_pseudo_string() { return (_ptr & _pseudo_bit) != 0; }
60
61 Symbol* get_symbol() {
62 return (Symbol*)(_ptr & ~_pseudo_bit);
63 }
64 };
65
66 // This represents a JVM_CONSTANT_Class, JVM_CONSTANT_UnresolvedClass, or
67 // JVM_CONSTANT_UnresolvedClassInError slot in the constant pool.
68 class CPKlassSlot VALUE_OBJ_CLASS_SPEC {
69 // cp->symbol_at(_name_index) gives the name of the class.
70 int _name_index;
71
72 // cp->_resolved_klasses->at(_resolved_klass_index) gives the Klass* for the class.
73 int _resolved_klass_index;
74 public:
75 enum {
76 // This is used during constant pool merging where the resolved klass index is
77 // not yet known, and will be computed at a later stage (during a call to
78 // initialize_unresolved_klasses()).
79 _temp_resolved_klass_index = 0xffff
80 };
81 CPKlassSlot(int n, int rk) {
82 _name_index = n;
83 _resolved_klass_index = rk;
84 }
85 int name_index() const {
86 return _name_index;
87 }
88 int resolved_klass_index() const {
89 assert(_resolved_klass_index != _temp_resolved_klass_index, "constant pool merging was incomplete");
90 return _resolved_klass_index;
91 }
92 };
93
94 class KlassSizeStats;
95
96 class ConstantPool : public Metadata {
97 friend class VMStructs;
98 friend class JVMCIVMStructs;
99 friend class BytecodeInterpreter; // Directly extracts a klass in the pool for fast instanceof/checkcast
100 friend class Universe; // For null constructor
101 private:
102 Array<u1>* _tags; // the tag array describing the constant pool's contents
103 ConstantPoolCache* _cache; // the cache holding interpreter runtime information
104 InstanceKlass* _pool_holder; // the corresponding class
105 Array<u2>* _operands; // for variable-sized (InvokeDynamic) nodes, usually empty
106
107 // Consider using an array of compressed klass pointers to
108 // save space on 64-bit platforms.
109 Array<Klass*>* _resolved_klasses;
110
111 enum {
112 _has_preresolution = 1, // Flags
113 _on_stack = 2,
114 _is_shared = 4
115 };
116
117 int _flags; // old fashioned bit twiddling
118 int _length; // number of elements in the array
119
120 union {
121 // set for CDS to restore resolved references
122 int _resolved_reference_length;
123 // keeps version number for redefined classes (used in backtrace)
124 int _version;
125 } _saved;
126
127 void set_tags(Array<u1>* tags) { _tags = tags; }
128 void tag_at_put(int which, jbyte t) { tags()->at_put(which, t); }
129 void release_tag_at_put(int which, jbyte t) { tags()->release_at_put(which, t); }
130
131 u1* tag_addr_at(int which) const { return tags()->adr_at(which); }
132
133 void set_operands(Array<u2>* operands) { _operands = operands; }
134
135 int flags() const { return _flags; }
136 void set_flags(int f) { _flags = f; }
137
138 private:
139 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
140
141 CPSlot slot_at(int which) const {
142 assert(is_within_bounds(which), "index out of bounds");
143 assert(!tag_at(which).is_unresolved_klass() && !tag_at(which).is_unresolved_klass_in_error(), "Corrupted constant pool");
144 // Uses volatile because the klass slot changes without a lock.
145 volatile intptr_t adr = (intptr_t)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which));
146 assert(adr != 0 || which == 0, "cp entry for klass should not be zero");
147 return CPSlot(adr);
148 }
149
150 void slot_at_put(int which, CPSlot s) const {
151 assert(is_within_bounds(which), "index out of bounds");
152 assert(s.value() != 0, "Caught something");
153 *(intptr_t*)&base()[which] = s.value();
154 }
155 intptr_t* obj_at_addr_raw(int which) const {
156 assert(is_within_bounds(which), "index out of bounds");
157 return (intptr_t*) &base()[which];
158 }
159
160 jint* int_at_addr(int which) const {
161 assert(is_within_bounds(which), "index out of bounds");
162 return (jint*) &base()[which];
163 }
164
165 jlong* long_at_addr(int which) const {
166 assert(is_within_bounds(which), "index out of bounds");
167 return (jlong*) &base()[which];
168 }
169
170 jfloat* float_at_addr(int which) const {
171 assert(is_within_bounds(which), "index out of bounds");
172 return (jfloat*) &base()[which];
173 }
174
175 jdouble* double_at_addr(int which) const {
176 assert(is_within_bounds(which), "index out of bounds");
177 return (jdouble*) &base()[which];
178 }
179
180 ConstantPool(Array<u1>* tags);
181 ConstantPool() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
182 public:
183 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
184
185 bool is_constantPool() const volatile { return true; }
186
187 Array<u1>* tags() const { return _tags; }
188 Array<u2>* operands() const { return _operands; }
189
190 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; }
191 void set_has_preresolution() {
192 assert(!is_shared(), "should never be called on shared ConstantPools");
193 _flags |= _has_preresolution;
194 }
195
196 // Redefine classes support. If a method refering to this constant pool
197 // is on the executing stack, or as a handle in vm code, this constant pool
198 // can't be removed from the set of previous versions saved in the instance
199 // class.
200 bool on_stack() const { return (_flags &_on_stack) != 0; }
201 void set_on_stack(const bool value);
202
203 // Faster than MetaspaceObj::is_shared() - used by set_on_stack()
204 bool is_shared() const { return (_flags & _is_shared) != 0; }
205
206 // Klass holding pool
207 InstanceKlass* pool_holder() const { return _pool_holder; }
208 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; }
209 InstanceKlass** pool_holder_addr() { return &_pool_holder; }
210
211 // Interpreter runtime support
212 ConstantPoolCache* cache() const { return _cache; }
213 void set_cache(ConstantPoolCache* cache){ _cache = cache; }
214
215 // Create object cache in the constant pool
216 void initialize_resolved_references(ClassLoaderData* loader_data,
217 const intStack& reference_map,
218 int constant_pool_map_length,
219 TRAPS);
220
221 // resolved strings, methodHandles and callsite objects from the constant pool
222 objArrayOop resolved_references() const;
223 // mapping resolved object array indexes to cp indexes and back.
224 int object_to_cp_index(int index) { return reference_map()->at(index); }
225 int cp_to_object_index(int index);
226
227 void set_resolved_klasses(Array<Klass*>* rk) { _resolved_klasses = rk; }
228 Array<Klass*>* resolved_klasses() const { return _resolved_klasses; }
229 void allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS);
230 void initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS);
231
232 // Invokedynamic indexes.
233 // They must look completely different from normal indexes.
234 // The main reason is that byte swapping is sometimes done on normal indexes.
235 // Finally, it is helpful for debugging to tell the two apart.
236 static bool is_invokedynamic_index(int i) { return (i < 0); }
237 static int decode_invokedynamic_index(int i) { assert(is_invokedynamic_index(i), ""); return ~i; }
238 static int encode_invokedynamic_index(int i) { assert(!is_invokedynamic_index(i), ""); return ~i; }
239
240
241 // The invokedynamic points at a CP cache entry. This entry points back
242 // at the original CP entry (CONSTANT_InvokeDynamic) and also (via f2) at an entry
243 // in the resolved_references array (which provides the appendix argument).
244 int invokedynamic_cp_cache_index(int index) const {
245 assert (is_invokedynamic_index(index), "should be a invokedynamic index");
246 int cache_index = decode_invokedynamic_index(index);
247 return cache_index;
248 }
249 ConstantPoolCacheEntry* invokedynamic_cp_cache_entry_at(int index) const {
250 // decode index that invokedynamic points to.
251 int cp_cache_index = invokedynamic_cp_cache_index(index);
252 return cache()->entry_at(cp_cache_index);
253 }
254
255 // Assembly code support
256 static int tags_offset_in_bytes() { return offset_of(ConstantPool, _tags); }
257 static int cache_offset_in_bytes() { return offset_of(ConstantPool, _cache); }
258 static int pool_holder_offset_in_bytes() { return offset_of(ConstantPool, _pool_holder); }
259 static int resolved_klasses_offset_in_bytes() { return offset_of(ConstantPool, _resolved_klasses); }
260
261 // Storing constants
262
263 // For temporary use while constructing constant pool
264 void klass_index_at_put(int which, int name_index) {
265 tag_at_put(which, JVM_CONSTANT_ClassIndex);
266 *int_at_addr(which) = name_index;
267 }
268
269 // Anonymous class support:
270 void klass_at_put(int class_index, int name_index, int resolved_klass_index, Klass* k, Symbol* name);
271 void klass_at_put(int class_index, Klass* k);
272
273 void unresolved_klass_at_put(int which, int name_index, int resolved_klass_index) {
274 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
275
276 assert((name_index & 0xffff0000) == 0, "must be");
277 assert((resolved_klass_index & 0xffff0000) == 0, "must be");
278 *int_at_addr(which) =
279 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
280 }
281
282 void method_handle_index_at_put(int which, int ref_kind, int ref_index) {
283 tag_at_put(which, JVM_CONSTANT_MethodHandle);
284 *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
285 }
286
287 void method_type_index_at_put(int which, int ref_index) {
288 tag_at_put(which, JVM_CONSTANT_MethodType);
289 *int_at_addr(which) = ref_index;
290 }
291
292 void invoke_dynamic_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) {
293 tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
294 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index;
295 }
296
297 void unresolved_string_at_put(int which, Symbol* s) {
298 release_tag_at_put(which, JVM_CONSTANT_String);
299 slot_at_put(which, CPSlot(s));
300 }
301
302 void int_at_put(int which, jint i) {
303 tag_at_put(which, JVM_CONSTANT_Integer);
304 *int_at_addr(which) = i;
305 }
306
307 void long_at_put(int which, jlong l) {
308 tag_at_put(which, JVM_CONSTANT_Long);
309 // *long_at_addr(which) = l;
310 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
311 }
312
313 void float_at_put(int which, jfloat f) {
314 tag_at_put(which, JVM_CONSTANT_Float);
315 *float_at_addr(which) = f;
316 }
317
318 void double_at_put(int which, jdouble d) {
319 tag_at_put(which, JVM_CONSTANT_Double);
320 // *double_at_addr(which) = d;
321 // u8 temp = *(u8*) &d;
322 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
323 }
324
325 Symbol** symbol_at_addr(int which) const {
326 assert(is_within_bounds(which), "index out of bounds");
327 return (Symbol**) &base()[which];
328 }
329
330 void symbol_at_put(int which, Symbol* s) {
331 assert(s->refcount() != 0, "should have nonzero refcount");
332 tag_at_put(which, JVM_CONSTANT_Utf8);
333 *symbol_at_addr(which) = s;
334 }
335
336 void string_at_put(int which, int obj_index, oop str);
337
338 // For temporary use while constructing constant pool
339 void string_index_at_put(int which, int string_index) {
340 tag_at_put(which, JVM_CONSTANT_StringIndex);
341 *int_at_addr(which) = string_index;
342 }
343
344 void field_at_put(int which, int class_index, int name_and_type_index) {
345 tag_at_put(which, JVM_CONSTANT_Fieldref);
346 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
347 }
348
349 void method_at_put(int which, int class_index, int name_and_type_index) {
350 tag_at_put(which, JVM_CONSTANT_Methodref);
351 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
352 }
353
354 void interface_method_at_put(int which, int class_index, int name_and_type_index) {
355 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
356 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
357 }
358
359 void name_and_type_at_put(int which, int name_index, int signature_index) {
360 tag_at_put(which, JVM_CONSTANT_NameAndType);
361 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice
362 }
363
364 // Tag query
365
366 constantTag tag_at(int which) const { return (constantTag)tags()->at_acquire(which); }
367
368 // Fetching constants
369
370 Klass* klass_at(int which, TRAPS) {
371 constantPoolHandle h_this(THREAD, this);
372 return klass_at_impl(h_this, which, true, THREAD);
373 }
374
375 // Version of klass_at that doesn't save the resolution error, called during deopt
376 Klass* klass_at_ignore_error(int which, TRAPS) {
377 constantPoolHandle h_this(THREAD, this);
378 return klass_at_impl(h_this, which, false, THREAD);
379 }
380
381 CPKlassSlot klass_slot_at(int which) const {
382 assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),
383 "Corrupted constant pool");
384 int value = *int_at_addr(which);
385 int name_index = extract_high_short_from_int(value);
386 int resolved_klass_index = extract_low_short_from_int(value);
387 return CPKlassSlot(name_index, resolved_klass_index);
388 }
389
390 Symbol* klass_name_at(int which) const; // Returns the name, w/o resolving.
391 int klass_name_index_at(int which) const {
392 return klass_slot_at(which).name_index();
393 }
394
395 Klass* resolved_klass_at(int which) const { // Used by Compiler
396 guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
397 // Must do an acquire here in case another thread resolved the klass
398 // behind our back, lest we later load stale values thru the oop.
399 CPKlassSlot kslot = klass_slot_at(which);
400 assert(tag_at(kslot.name_index()).is_symbol(), "sanity");
401
402 Klass** adr = resolved_klasses()->adr_at(kslot.resolved_klass_index());
403 return (Klass*)OrderAccess::load_ptr_acquire(adr);
404 }
405
406 // RedefineClasses() API support:
407 Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
408 void temp_unresolved_klass_at_put(int which, int name_index) {
409 // Used only during constant pool merging for class redefinition. The resolved klass index
410 // will be initialized later by a call to initialize_unresolved_klasses().
411 unresolved_klass_at_put(which, name_index, CPKlassSlot::_temp_resolved_klass_index);
412 }
413
414 jint int_at(int which) {
415 assert(tag_at(which).is_int(), "Corrupted constant pool");
416 return *int_at_addr(which);
417 }
418
419 jlong long_at(int which) {
420 assert(tag_at(which).is_long(), "Corrupted constant pool");
421 // return *long_at_addr(which);
422 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
423 return *((jlong*)&tmp);
424 }
425
426 jfloat float_at(int which) {
427 assert(tag_at(which).is_float(), "Corrupted constant pool");
428 return *float_at_addr(which);
429 }
430
431 jdouble double_at(int which) {
432 assert(tag_at(which).is_double(), "Corrupted constant pool");
433 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
434 return *((jdouble*)&tmp);
435 }
436
437 Symbol* symbol_at(int which) const {
438 assert(tag_at(which).is_utf8(), "Corrupted constant pool");
439 return *symbol_at_addr(which);
440 }
441
442 oop string_at(int which, int obj_index, TRAPS) {
443 constantPoolHandle h_this(THREAD, this);
444 return string_at_impl(h_this, which, obj_index, THREAD);
445 }
446 oop string_at(int which, TRAPS) {
447 int obj_index = cp_to_object_index(which);
448 return string_at(which, obj_index, THREAD);
449 }
450
451 // Version that can be used before string oop array is created.
452 oop uncached_string_at(int which, TRAPS);
453
454 // A "pseudo-string" is an non-string oop that has found its way into
455 // a String entry.
456 // This can happen if the user patches a live
457 // object into a CONSTANT_String entry of an anonymous class.
458 // Method oops internally created for method handles may also
459 // use pseudo-strings to link themselves to related metaobjects.
460
461 bool is_pseudo_string_at(int which) {
462 assert(tag_at(which).is_string(), "Corrupted constant pool");
463 return slot_at(which).is_pseudo_string();
464 }
465
466 oop pseudo_string_at(int which, int obj_index) {
467 assert(is_pseudo_string_at(which), "must be a pseudo-string");
468 oop s = resolved_references()->obj_at(obj_index);
469 return s;
470 }
471
472 oop pseudo_string_at(int which) {
473 assert(is_pseudo_string_at(which), "must be a pseudo-string");
474 int obj_index = cp_to_object_index(which);
475 oop s = resolved_references()->obj_at(obj_index);
476 return s;
477 }
478
479 void pseudo_string_at_put(int which, int obj_index, oop x) {
480 assert(tag_at(which).is_string(), "Corrupted constant pool");
481 Symbol* sym = unresolved_string_at(which);
482 slot_at_put(which, CPSlot(sym, CPSlot::_pseudo_bit));
483 string_at_put(which, obj_index, x); // this works just fine
484 }
485
486 // only called when we are sure a string entry is already resolved (via an
487 // earlier string_at call.
488 oop resolved_string_at(int which) {
489 assert(tag_at(which).is_string(), "Corrupted constant pool");
490 // Must do an acquire here in case another thread resolved the klass
491 // behind our back, lest we later load stale values thru the oop.
492 // we might want a volatile_obj_at in ObjArrayKlass.
493 int obj_index = cp_to_object_index(which);
494 return resolved_references()->obj_at(obj_index);
495 }
496
497 Symbol* unresolved_string_at(int which) {
498 assert(tag_at(which).is_string(), "Corrupted constant pool");
499 Symbol* sym = slot_at(which).get_symbol();
500 return sym;
501 }
502
503 // Returns an UTF8 for a CONSTANT_String entry at a given index.
504 // UTF8 char* representation was chosen to avoid conversion of
505 // java_lang_Strings at resolved entries into Symbol*s
506 // or vice versa.
507 char* string_at_noresolve(int which);
508
509 jint name_and_type_at(int which) {
510 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
511 return *int_at_addr(which);
512 }
513
514 int method_handle_ref_kind_at(int which) {
515 assert(tag_at(which).is_method_handle() ||
516 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
517 return extract_low_short_from_int(*int_at_addr(which)); // mask out unwanted ref_index bits
518 }
519 int method_handle_index_at(int which) {
520 assert(tag_at(which).is_method_handle() ||
521 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
522 return extract_high_short_from_int(*int_at_addr(which)); // shift out unwanted ref_kind bits
523 }
524 int method_type_index_at(int which) {
525 assert(tag_at(which).is_method_type() ||
526 tag_at(which).is_method_type_in_error(), "Corrupted constant pool");
527 return *int_at_addr(which);
528 }
529
530 // Derived queries:
531 Symbol* method_handle_name_ref_at(int which) {
532 int member = method_handle_index_at(which);
533 return impl_name_ref_at(member, true);
534 }
535 Symbol* method_handle_signature_ref_at(int which) {
536 int member = method_handle_index_at(which);
537 return impl_signature_ref_at(member, true);
538 }
539 int method_handle_klass_index_at(int which) {
540 int member = method_handle_index_at(which);
541 return impl_klass_ref_index_at(member, true);
542 }
543 Symbol* method_type_signature_at(int which) {
544 int sym = method_type_index_at(which);
545 return symbol_at(sym);
546 }
547
548 int invoke_dynamic_name_and_type_ref_index_at(int which) {
549 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
550 return extract_high_short_from_int(*int_at_addr(which));
551 }
552 int invoke_dynamic_bootstrap_specifier_index(int which) {
553 assert(tag_at(which).value() == JVM_CONSTANT_InvokeDynamic, "Corrupted constant pool");
554 return extract_low_short_from_int(*int_at_addr(which));
555 }
556 int invoke_dynamic_operand_base(int which) {
557 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
558 return operand_offset_at(operands(), bootstrap_specifier_index);
559 }
560 // The first part of the operands array consists of an index into the second part.
561 // Extract a 32-bit index value from the first part.
562 static int operand_offset_at(Array<u2>* operands, int bootstrap_specifier_index) {
563 int n = (bootstrap_specifier_index * 2);
564 assert(n >= 0 && n+2 <= operands->length(), "oob");
565 // The first 32-bit index points to the beginning of the second part
566 // of the operands array. Make sure this index is in the first part.
567 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
568 operands->at(1)));
569 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
570 int offset = build_int_from_shorts(operands->at(n+0),
571 operands->at(n+1));
572 // The offset itself must point into the second part of the array.
573 assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
574 return offset;
575 }
576 static void operand_offset_at_put(Array<u2>* operands, int bootstrap_specifier_index, int offset) {
577 int n = bootstrap_specifier_index * 2;
578 assert(n >= 0 && n+2 <= operands->length(), "oob");
579 operands->at_put(n+0, extract_low_short_from_int(offset));
580 operands->at_put(n+1, extract_high_short_from_int(offset));
581 }
582 static int operand_array_length(Array<u2>* operands) {
583 if (operands == NULL || operands->length() == 0) return 0;
584 int second_part = operand_offset_at(operands, 0);
585 return (second_part / 2);
586 }
587
588 #ifdef ASSERT
589 // operand tuples fit together exactly, end to end
590 static int operand_limit_at(Array<u2>* operands, int bootstrap_specifier_index) {
591 int nextidx = bootstrap_specifier_index + 1;
592 if (nextidx == operand_array_length(operands))
593 return operands->length();
594 else
595 return operand_offset_at(operands, nextidx);
596 }
597 int invoke_dynamic_operand_limit(int which) {
598 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
599 return operand_limit_at(operands(), bootstrap_specifier_index);
600 }
601 #endif //ASSERT
602
603 // layout of InvokeDynamic bootstrap method specifier (in second part of operands array):
604 enum {
605 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
606 _indy_argc_offset = 1, // u2 argc
607 _indy_argv_offset = 2 // u2 argv[argc]
608 };
609
610 // These functions are used in RedefineClasses for CP merge
611
612 int operand_offset_at(int bootstrap_specifier_index) {
613 assert(0 <= bootstrap_specifier_index &&
614 bootstrap_specifier_index < operand_array_length(operands()),
615 "Corrupted CP operands");
616 return operand_offset_at(operands(), bootstrap_specifier_index);
617 }
618 int operand_bootstrap_method_ref_index_at(int bootstrap_specifier_index) {
619 int offset = operand_offset_at(bootstrap_specifier_index);
620 return operands()->at(offset + _indy_bsm_offset);
621 }
622 int operand_argument_count_at(int bootstrap_specifier_index) {
623 int offset = operand_offset_at(bootstrap_specifier_index);
624 int argc = operands()->at(offset + _indy_argc_offset);
625 return argc;
626 }
627 int operand_argument_index_at(int bootstrap_specifier_index, int j) {
628 int offset = operand_offset_at(bootstrap_specifier_index);
629 return operands()->at(offset + _indy_argv_offset + j);
630 }
631 int operand_next_offset_at(int bootstrap_specifier_index) {
632 int offset = operand_offset_at(bootstrap_specifier_index) + _indy_argv_offset
633 + operand_argument_count_at(bootstrap_specifier_index);
634 return offset;
635 }
636 // Compare a bootsrap specifier in the operands arrays
637 bool compare_operand_to(int bootstrap_specifier_index1, const constantPoolHandle& cp2,
638 int bootstrap_specifier_index2, TRAPS);
639 // Find a bootsrap specifier in the operands array
640 int find_matching_operand(int bootstrap_specifier_index, const constantPoolHandle& search_cp,
641 int operands_cur_len, TRAPS);
642 // Resize the operands array with delta_len and delta_size
643 void resize_operands(int delta_len, int delta_size, TRAPS);
644 // Extend the operands array with the length and size of the ext_cp operands
645 void extend_operands(const constantPoolHandle& ext_cp, TRAPS);
646 // Shrink the operands array to a smaller array with new_len length
647 void shrink_operands(int new_len, TRAPS);
648
649
650 int invoke_dynamic_bootstrap_method_ref_index_at(int which) {
651 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
652 int op_base = invoke_dynamic_operand_base(which);
653 return operands()->at(op_base + _indy_bsm_offset);
654 }
655 int invoke_dynamic_argument_count_at(int which) {
656 assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
657 int op_base = invoke_dynamic_operand_base(which);
658 int argc = operands()->at(op_base + _indy_argc_offset);
659 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
660 int next_offset = invoke_dynamic_operand_limit(which));
661 assert(end_offset == next_offset, "matched ending");
662 return argc;
663 }
664 int invoke_dynamic_argument_index_at(int which, int j) {
665 int op_base = invoke_dynamic_operand_base(which);
666 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
667 assert((uint)j < (uint)argc, "oob");
668 return operands()->at(op_base + _indy_argv_offset + j);
669 }
670
671 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
672 // name_and_type_ref_index_at) all expect to be passed indices obtained
673 // directly from the bytecode.
674 // If the indices are meant to refer to fields or methods, they are
675 // actually rewritten constant pool cache indices.
676 // The routine remap_instruction_operand_from_cache manages the adjustment
677 // of these values back to constant pool indices.
678
679 // There are also "uncached" versions which do not adjust the operand index; see below.
680
681 // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear.
682 // In a few cases (the verifier) there are uses before a cpcache has been built,
683 // which are handled by a dynamic check in remap_instruction_operand_from_cache.
684 // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode.
685
686 // Lookup for entries consisting of (klass_index, name_and_type index)
687 Klass* klass_ref_at(int which, TRAPS);
688 Symbol* klass_ref_at_noresolve(int which);
689 Symbol* name_ref_at(int which) { return impl_name_ref_at(which, false); }
690 Symbol* signature_ref_at(int which) { return impl_signature_ref_at(which, false); }
691
692 int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); }
693 int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); }
694
695 int remap_instruction_operand_from_cache(int operand); // operand must be biased by CPCACHE_INDEX_TAG
696
697 constantTag tag_ref_at(int cp_cache_index) { return impl_tag_ref_at(cp_cache_index, false); }
698
699 // Lookup for entries consisting of (name_index, signature_index)
700 int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt)
701 int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt)
702
703 BasicType basic_type_for_signature_at(int which) const;
704
705 // Resolve string constants (to prevent allocation during compilation)
706 void resolve_string_constants(TRAPS) {
707 constantPoolHandle h_this(THREAD, this);
708 resolve_string_constants_impl(h_this, CHECK);
709 }
710
711 // CDS support
712 void remove_unshareable_info();
713 void restore_unshareable_info(TRAPS);
714 bool resolve_class_constants(TRAPS);
715 // The ConstantPool vtable is restored by this call when the ConstantPool is
716 // in the shared archive. See patch_klass_vtables() in metaspaceShared.cpp for
717 // all the gory details. SA, dtrace and pstack helpers distinguish metadata
718 // by their vtable.
719 void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); }
720
721 private:
722 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
723 public:
724
725 // Resolve late bound constants.
726 oop resolve_constant_at(int index, TRAPS) {
727 constantPoolHandle h_this(THREAD, this);
728 return resolve_constant_at_impl(h_this, index, _no_index_sentinel, THREAD);
729 }
730
731 oop resolve_cached_constant_at(int cache_index, TRAPS) {
732 constantPoolHandle h_this(THREAD, this);
733 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, THREAD);
734 }
735
736 oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
737 constantPoolHandle h_this(THREAD, this);
738 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, THREAD);
739 }
740
741 oop resolve_bootstrap_specifier_at(int index, TRAPS) {
742 constantPoolHandle h_this(THREAD, this);
743 return resolve_bootstrap_specifier_at_impl(h_this, index, THREAD);
744 }
745
746 // Klass name matches name at offset
747 bool klass_name_at_matches(const InstanceKlass* k, int which);
748
749 // Sizing
750 int length() const { return _length; }
751 void set_length(int length) { _length = length; }
752
753 // Tells whether index is within bounds.
754 bool is_within_bounds(int index) const {
755 return 0 <= index && index < length();
756 }
757
758 // Sizing (in words)
759 static int header_size() {
760 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize;
761 }
762 static int size(int length) { return align_metadata_size(header_size() + length); }
763 int size() const { return size(length()); }
764 #if INCLUDE_SERVICES
765 void collect_statistics(KlassSizeStats *sz) const;
766 #endif
767
768 friend class ClassFileParser;
769 friend class SystemDictionary;
770
771 // Used by CDS. These classes need to access the private ConstantPool() constructor.
772 template <class T> friend class CppVtableTesterA;
773 template <class T> friend class CppVtableTesterB;
774 template <class T> friend class CppVtableCloner;
775
776 // Used by compiler to prevent classloading.
777 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which);
778 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
779 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
780 static bool has_method_type_at_if_loaded (const constantPoolHandle& this_cp, int which);
781 static oop method_type_at_if_loaded (const constantPoolHandle& this_cp, int which);
782 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which);
783 static Klass* klass_ref_at_if_loaded (const constantPoolHandle& this_cp, int which);
784
785 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
786 // future by other Java code. These take constant pool indices rather than
787 // constant pool cache indices as do the peer methods above.
788 Symbol* uncached_klass_ref_at_noresolve(int which);
789 Symbol* uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); }
790 Symbol* uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); }
791 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); }
792 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); }
793
794 // Sharing
795 int pre_resolve_shared_klasses(TRAPS);
796
797 // Debugging
798 const char* printable_name_at(int which) PRODUCT_RETURN0;
799
800 #ifdef ASSERT
801 enum { CPCACHE_INDEX_TAG = 0x10000 }; // helps keep CP cache indices distinct from CP indices
802 #else
803 enum { CPCACHE_INDEX_TAG = 0 }; // in product mode, this zero value is a no-op
804 #endif //ASSERT
805
806 static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) {
807 if (invokedynamic_ok && is_invokedynamic_index(raw_index))
808 return decode_invokedynamic_index(raw_index);
809 else
810 return raw_index - CPCACHE_INDEX_TAG;
811 }
812
813 private:
814
815 void set_resolved_references(jobject s) { _cache->set_resolved_references(s); }
816 Array<u2>* reference_map() const { return (_cache == NULL) ? NULL : _cache->reference_map(); }
817 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); }
818
819 // patch JSR 292 resolved references after the class is linked.
820 void patch_resolved_references(GrowableArray<Handle>* cp_patches);
821
822 Symbol* impl_name_ref_at(int which, bool uncached);
823 Symbol* impl_signature_ref_at(int which, bool uncached);
824 int impl_klass_ref_index_at(int which, bool uncached);
825 int impl_name_and_type_ref_index_at(int which, bool uncached);
826 constantTag impl_tag_ref_at(int which, bool uncached);
827
828 // Used while constructing constant pool (only by ClassFileParser)
829 jint klass_index_at(int which) {
830 assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
831 return *int_at_addr(which);
832 }
833
834 jint string_index_at(int which) {
835 assert(tag_at(which).is_string_index(), "Corrupted constant pool");
836 return *int_at_addr(which);
837 }
838
839 // Performs the LinkResolver checks
840 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS);
841
842 // Implementation of methods that needs an exposed 'this' pointer, in order to
843 // handle GC while executing the method
844 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int which,
845 bool save_resolution_error, TRAPS);
846 static oop string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS);
847
848 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k);
849
850 // Resolve string constants (to prevent allocation during compilation)
851 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS);
852
853 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int index, int cache_index, TRAPS);
854 static oop resolve_bootstrap_specifier_at_impl(const constantPoolHandle& this_cp, int index, TRAPS);
855
856 // Exception handling
857 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS);
858 static Symbol* exception_message(const constantPoolHandle& this_cp, int which, constantTag tag, oop pending_exception);
859 static void save_and_throw_exception(const constantPoolHandle& this_cp, int which, constantTag tag, TRAPS);
860
861 public:
862 // Merging ConstantPool* support:
863 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2, TRAPS);
864 void copy_cp_to(int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS) {
865 constantPoolHandle h_this(THREAD, this);
866 copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
867 }
868 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
869 static void copy_entry_to(const constantPoolHandle& from_cp, int from_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
870 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS);
871 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp, TRAPS);
872 int version() const { return _saved._version; }
873 void set_version(int version) { _saved._version = version; }
874 void increment_and_save_version(int version) {
875 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow
876 }
877
878 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
879 int resolved_reference_length() const { return _saved._resolved_reference_length; }
880
881 // Decrease ref counts of symbols that are in the constant pool
882 // when the holder class is unloaded
883 void unreference_symbols();
884
885 // Deallocate constant pool for RedefineClasses
886 void deallocate_contents(ClassLoaderData* loader_data);
887 void release_C_heap_structures();
888
889 // JVMTI accesss - GetConstantPool, RetransformClasses, ...
890 friend class JvmtiConstantPoolReconstituter;
891
892 private:
893 jint cpool_entry_size(jint idx);
894 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
895
896 // Copy cpool bytes into byte array.
897 // Returns:
898 // int > 0, count of the raw cpool bytes that have been copied
899 // 0, OutOfMemory error
900 // -1, Internal error
901 int copy_cpool_bytes(int cpool_size,
902 SymbolHashMap* tbl,
903 unsigned char *bytes);
904
905 public:
906 // Verify
907 void verify_on(outputStream* st);
908
909 // Printing
910 void print_on(outputStream* st) const;
911 void print_value_on(outputStream* st) const;
912 void print_entry_on(int index, outputStream* st);
913
914 const char* internal_name() const { return "{constant pool}"; }
915
916 #ifndef PRODUCT
917 // Compile the world support
918 static void preload_and_initialize_all_classes(ConstantPool* constant_pool, TRAPS);
919 #endif
920 };
921
922 class SymbolHashMapEntry : public CHeapObj<mtSymbol> {
923 private:
924 unsigned int _hash; // 32-bit hash for item
925 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket
926 Symbol* _symbol; // 1-st part of the mapping: symbol => value
927 u2 _value; // 2-nd part of the mapping: symbol => value
928
929 public:
930 unsigned int hash() const { return _hash; }
931 void set_hash(unsigned int hash) { _hash = hash; }
932
933 SymbolHashMapEntry* next() const { return _next; }
934 void set_next(SymbolHashMapEntry* next) { _next = next; }
935
936 Symbol* symbol() const { return _symbol; }
937 void set_symbol(Symbol* sym) { _symbol = sym; }
938
939 u2 value() const { return _value; }
940 void set_value(u2 value) { _value = value; }
941
942 SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
943 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
944
945 }; // End SymbolHashMapEntry class
946
947
948 class SymbolHashMapBucket : public CHeapObj<mtSymbol> {
949
950 private:
951 SymbolHashMapEntry* _entry;
952
953 public:
954 SymbolHashMapEntry* entry() const { return _entry; }
955 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
956 void clear() { _entry = NULL; }
957
958 }; // End SymbolHashMapBucket class
959
960
961 class SymbolHashMap: public CHeapObj<mtSymbol> {
962
963 private:
964 // Default number of entries in the table
965 enum SymbolHashMap_Constants {
966 _Def_HashMap_Size = 256
967 };
968
969 int _table_size;
970 SymbolHashMapBucket* _buckets;
971
972 void initialize_table(int table_size) {
973 _table_size = table_size;
974 _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size, mtSymbol);
975 for (int index = 0; index < table_size; index++) {
976 _buckets[index].clear();
977 }
978 }
979
980 public:
981
982 int table_size() const { return _table_size; }
983
984 SymbolHashMap() { initialize_table(_Def_HashMap_Size); }
985 SymbolHashMap(int table_size) { initialize_table(table_size); }
986
987 // hash P(31) from Kernighan & Ritchie
988 static unsigned int compute_hash(const char* str, int len) {
989 unsigned int hash = 0;
990 while (len-- > 0) {
991 hash = 31*hash + (unsigned) *str;
992 str++;
993 }
994 return hash;
995 }
996
997 SymbolHashMapEntry* bucket(int i) {
998 return _buckets[i].entry();
999 }
1000
1001 void add_entry(Symbol* sym, u2 value);
1002 SymbolHashMapEntry* find_entry(Symbol* sym);
1003
1004 u2 symbol_to_value(Symbol* sym) {
1005 SymbolHashMapEntry *entry = find_entry(sym);
1006 return (entry == NULL) ? 0 : entry->value();
1007 }
1008
1009 ~SymbolHashMap() {
1010 SymbolHashMapEntry* next;
1011 for (int i = 0; i < _table_size; i++) {
1012 for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
1013 next = cur->next();
1014 delete(cur);
1015 }
1016 }
1017 delete _buckets;
1018 }
1019 }; // End SymbolHashMap class
1020
1021 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP