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