1 /*
2 * Copyright (c) 1997, 2019, 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 *
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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).
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23 */
24
25 #ifndef SHARE_OOPS_CONSTANTPOOL_HPP
26 #define SHARE_OOPS_CONSTANTPOOL_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/arrayOop.hpp"
30 #include "oops/cpCache.hpp"
31 #include "oops/objArrayOop.hpp"
32 #include "oops/oopHandle.hpp"
33 #include "oops/symbol.hpp"
34 #include "oops/typeArrayOop.hpp"
35 #include "runtime/handles.hpp"
36 #include "utilities/align.hpp"
37 #include "utilities/bytes.hpp"
38 #include "utilities/constantTag.hpp"
39
40 // A ConstantPool is an array containing class constants as described in the
41 // class file.
42 //
43 // Most of the constant pool entries are written during class parsing, which
44 // is safe. For klass types, the constant pool entry is
45 // modified when the entry is resolved. If a klass constant pool
46 // entry is read without a lock, only the resolved state guarantees that
47 // the entry in the constant pool is a klass object and not a Symbol*.
48
49 class SymbolHashMap;
50
51 class CPSlot {
52 friend class ConstantPool;
53 intptr_t _ptr;
54 enum TagBits {_pseudo_bit = 1};
55 public:
56
57 CPSlot(intptr_t ptr): _ptr(ptr) {}
58 CPSlot(Symbol* ptr, int tag_bits = 0): _ptr((intptr_t)ptr | tag_bits) {}
59
60 intptr_t value() { return _ptr; }
61 bool is_pseudo_string() { return (_ptr & _pseudo_bit) != 0; }
62
63 Symbol* get_symbol() {
64 return (Symbol*)(_ptr & ~_pseudo_bit);
65 }
66 };
67
68 // This represents a JVM_CONSTANT_Class, JVM_CONSTANT_UnresolvedClass, or
69 // JVM_CONSTANT_UnresolvedClassInError slot in the constant pool.
70 class CPKlassSlot {
71 // cp->symbol_at(_name_index) gives the name of the class.
72 int _name_index;
73
74 // cp->_resolved_klasses->at(_resolved_klass_index) gives the Klass* for the class.
75 int _resolved_klass_index;
76 public:
77 enum {
78 // This is used during constant pool merging where the resolved klass index is
79 // not yet known, and will be computed at a later stage (during a call to
80 // initialize_unresolved_klasses()).
81 _temp_resolved_klass_index = 0xffff
82 };
83 CPKlassSlot(int n, int rk) {
84 _name_index = n;
85 _resolved_klass_index = rk;
86 }
87 int name_index() const {
88 return _name_index;
89 }
90 int resolved_klass_index() const {
91 assert(_resolved_klass_index != _temp_resolved_klass_index, "constant pool merging was incomplete");
92 return _resolved_klass_index;
93 }
94 };
95
96 class KlassSizeStats;
97
98 class ConstantPool : public Metadata {
99 friend class VMStructs;
100 friend class JVMCIVMStructs;
101 friend class BytecodeInterpreter; // Directly extracts a klass in the pool for fast instanceof/checkcast
102 friend class Universe; // For null constructor
103 private:
104 // If you add a new field that points to any metaspace object, you
105 // must add this field to ConstantPool::metaspace_pointers_do().
106 Array<u1>* _tags; // the tag array describing the constant pool's contents
107 ConstantPoolCache* _cache; // the cache holding interpreter runtime information
108 InstanceKlass* _pool_holder; // the corresponding class
109 Array<u2>* _operands; // for variable-sized (InvokeDynamic) nodes, usually empty
110
111 // Consider using an array of compressed klass pointers to
112 // save space on 64-bit platforms.
113 Array<Klass*>* _resolved_klasses;
114
115 enum {
116 _has_preresolution = 1, // Flags
117 _on_stack = 2,
118 _is_shared = 4,
119 _has_dynamic_constant = 8
120 };
121
122 int _flags; // old fashioned bit twiddling
123 int _length; // number of elements in the array
124
125 union {
126 // set for CDS to restore resolved references
127 int _resolved_reference_length;
128 // keeps version number for redefined classes (used in backtrace)
129 int _version;
130 } _saved;
131
132 void set_tags(Array<u1>* tags) { _tags = tags; }
133 void tag_at_put(int which, jbyte t) { tags()->at_put(which, t); }
134 void release_tag_at_put(int which, jbyte t) { tags()->release_at_put(which, t); }
135
136 u1* tag_addr_at(int which) const { return tags()->adr_at(which); }
137
138 void set_operands(Array<u2>* operands) { _operands = operands; }
139
140 int flags() const { return _flags; }
141 void set_flags(int f) { _flags = f; }
142
143 private:
144 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
145
146 CPSlot slot_at(int which) const;
147
148 void slot_at_put(int which, CPSlot s) const {
149 assert(is_within_bounds(which), "index out of bounds");
150 assert(s.value() != 0, "Caught something");
151 *(intptr_t*)&base()[which] = s.value();
152 }
153 intptr_t* obj_at_addr(int which) const {
154 assert(is_within_bounds(which), "index out of bounds");
155 return (intptr_t*) &base()[which];
156 }
157
158 jint* int_at_addr(int which) const {
159 assert(is_within_bounds(which), "index out of bounds");
160 return (jint*) &base()[which];
161 }
162
163 jlong* long_at_addr(int which) const {
164 assert(is_within_bounds(which), "index out of bounds");
165 return (jlong*) &base()[which];
166 }
167
168 jfloat* float_at_addr(int which) const {
169 assert(is_within_bounds(which), "index out of bounds");
170 return (jfloat*) &base()[which];
171 }
172
173 jdouble* double_at_addr(int which) const {
174 assert(is_within_bounds(which), "index out of bounds");
175 return (jdouble*) &base()[which];
176 }
177
178 ConstantPool(Array<u1>* tags);
179 ConstantPool() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
180 public:
181 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
182
183 bool is_constantPool() const volatile { return true; }
184
185 Array<u1>* tags() const { return _tags; }
186 Array<u2>* operands() const { return _operands; }
187
188 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; }
189 void set_has_preresolution() {
190 assert(!is_shared(), "should never be called on shared ConstantPools");
191 _flags |= _has_preresolution;
192 }
193
194 // Redefine classes support. If a method refering to this constant pool
195 // is on the executing stack, or as a handle in vm code, this constant pool
196 // can't be removed from the set of previous versions saved in the instance
197 // class.
198 bool on_stack() const { return (_flags &_on_stack) != 0; }
199 void set_on_stack(const bool value);
200
201 // Faster than MetaspaceObj::is_shared() - used by set_on_stack()
202 bool is_shared() const { return (_flags & _is_shared) != 0; }
203
204 bool has_dynamic_constant() const { return (_flags & _has_dynamic_constant) != 0; }
205 void set_has_dynamic_constant() { _flags |= _has_dynamic_constant; }
206
207 // Klass holding pool
208 InstanceKlass* pool_holder() const { return _pool_holder; }
209 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; }
210 InstanceKlass** pool_holder_addr() { return &_pool_holder; }
211
212 // Interpreter runtime support
213 ConstantPoolCache* cache() const { return _cache; }
214 void set_cache(ConstantPoolCache* cache){ _cache = cache; }
215
216 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
217 virtual MetaspaceObj::Type type() const { return ConstantPoolType; }
218
219 // Create object cache in the constant pool
220 void initialize_resolved_references(ClassLoaderData* loader_data,
221 const intStack& reference_map,
222 int constant_pool_map_length,
223 TRAPS);
224
225 // resolved strings, methodHandles and callsite objects from the constant pool
226 objArrayOop resolved_references() const;
227 objArrayOop resolved_references_or_null() 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 indy_index) const {
250 assert(is_invokedynamic_index(indy_index), "should be a invokedynamic index");
251 int cache_index = decode_invokedynamic_index(indy_index);
252 return cache_index;
253 }
254 ConstantPoolCacheEntry* invokedynamic_cp_cache_entry_at(int indy_index) const {
255 // decode index that invokedynamic points to.
256 int cp_cache_index = invokedynamic_cp_cache_index(indy_index);
257 return cache()->entry_at(cp_cache_index);
258 }
259 // Given the per-instruction index of an indy instruction, report the
260 // main constant pool entry for its bootstrap specifier.
261 // From there, uncached_name/signature_ref_at will get the name/type.
262 int invokedynamic_bootstrap_ref_index_at(int indy_index) const {
263 return invokedynamic_cp_cache_entry_at(indy_index)->constant_pool_index();
264 }
265
266 // Assembly code support
267 static int tags_offset_in_bytes() { return offset_of(ConstantPool, _tags); }
268 static int cache_offset_in_bytes() { return offset_of(ConstantPool, _cache); }
269 static int pool_holder_offset_in_bytes() { return offset_of(ConstantPool, _pool_holder); }
270 static int resolved_klasses_offset_in_bytes() { return offset_of(ConstantPool, _resolved_klasses); }
271
272 // Storing constants
273
274 // For temporary use while constructing constant pool. Used during a retransform/class redefinition as well.
275 void klass_index_at_put(int which, int name_index) {
276 tag_at_put(which, JVM_CONSTANT_ClassIndex);
277 *int_at_addr(which) = name_index;
278 }
279
280 // Unsafe anonymous class support:
281 void klass_at_put(int class_index, int name_index, int resolved_klass_index, Klass* k, Symbol* name);
282 void klass_at_put(int class_index, Klass* k);
283
284 void unresolved_qdescriptor_at_put(int which, int name_index, int resolved_klass_index) {
285 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass | (jbyte)JVM_CONSTANT_QDESC_BIT);
286
287 assert((name_index & 0xffff0000) == 0, "must be");
288 assert((resolved_klass_index & 0xffff0000) == 0, "must be");
289 *int_at_addr(which) =
290 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
291 }
292
293 void unresolved_klass_at_put(int which, int name_index, int resolved_klass_index) {
294 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
295
296 assert((name_index & 0xffff0000) == 0, "must be");
297 assert((resolved_klass_index & 0xffff0000) == 0, "must be");
298 *int_at_addr(which) =
299 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
300 }
301
302 void method_handle_index_at_put(int which, int ref_kind, int ref_index) {
303 tag_at_put(which, JVM_CONSTANT_MethodHandle);
304 *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
305 }
306
307 void method_type_index_at_put(int which, int ref_index) {
308 tag_at_put(which, JVM_CONSTANT_MethodType);
309 *int_at_addr(which) = ref_index;
310 }
311
312 void dynamic_constant_at_put(int which, int bsms_attribute_index, int name_and_type_index) {
313 tag_at_put(which, JVM_CONSTANT_Dynamic);
314 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
315 }
316
317 void invoke_dynamic_at_put(int which, int bsms_attribute_index, int name_and_type_index) {
318 tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
319 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
320 }
321
322 void unresolved_string_at_put(int which, Symbol* s) {
323 release_tag_at_put(which, JVM_CONSTANT_String);
324 slot_at_put(which, CPSlot(s));
325 }
326
327 void int_at_put(int which, jint i) {
328 tag_at_put(which, JVM_CONSTANT_Integer);
329 *int_at_addr(which) = i;
330 }
331
332 void long_at_put(int which, jlong l) {
333 tag_at_put(which, JVM_CONSTANT_Long);
334 // *long_at_addr(which) = l;
335 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
336 }
337
338 void float_at_put(int which, jfloat f) {
339 tag_at_put(which, JVM_CONSTANT_Float);
340 *float_at_addr(which) = f;
341 }
342
343 void double_at_put(int which, jdouble d) {
344 tag_at_put(which, JVM_CONSTANT_Double);
345 // *double_at_addr(which) = d;
346 // u8 temp = *(u8*) &d;
347 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
348 }
349
350 Symbol** symbol_at_addr(int which) const {
351 assert(is_within_bounds(which), "index out of bounds");
352 return (Symbol**) &base()[which];
353 }
354
355 void symbol_at_put(int which, Symbol* s) {
356 assert(s->refcount() != 0, "should have nonzero refcount");
357 tag_at_put(which, JVM_CONSTANT_Utf8);
358 *symbol_at_addr(which) = s;
359 }
360
361 void string_at_put(int which, int obj_index, oop str);
362
363 // For temporary use while constructing constant pool
364 void string_index_at_put(int which, int string_index) {
365 tag_at_put(which, JVM_CONSTANT_StringIndex);
366 *int_at_addr(which) = string_index;
367 }
368
369 void field_at_put(int which, int class_index, int name_and_type_index) {
370 tag_at_put(which, JVM_CONSTANT_Fieldref);
371 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
372 }
373
374 void method_at_put(int which, int class_index, int name_and_type_index) {
375 tag_at_put(which, JVM_CONSTANT_Methodref);
376 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
377 }
378
379 void interface_method_at_put(int which, int class_index, int name_and_type_index) {
380 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
381 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
382 }
383
384 void name_and_type_at_put(int which, int name_index, int signature_index) {
385 tag_at_put(which, JVM_CONSTANT_NameAndType);
386 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice
387 }
388
389 // Tag query
390
391 constantTag tag_at(int which) const { return (constantTag)tags()->at_acquire(which); }
392
393 // Fetching constants
394
395 Klass* klass_at(int which, TRAPS) {
396 constantPoolHandle h_this(THREAD, this);
397 return klass_at_impl(h_this, which, true, THREAD);
398 }
399
400 // Version of klass_at that doesn't save the resolution error, called during deopt
401 Klass* klass_at_ignore_error(int which, TRAPS) {
402 constantPoolHandle h_this(THREAD, this);
403 return klass_at_impl(h_this, which, false, THREAD);
404 }
405
406 CPKlassSlot klass_slot_at(int which) const {
407 assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),
408 "Corrupted constant pool");
409 int value = *int_at_addr(which);
410 int name_index = extract_high_short_from_int(value);
411 int resolved_klass_index = extract_low_short_from_int(value);
412 return CPKlassSlot(name_index, resolved_klass_index);
413 }
414
415 Symbol* klass_name_at(int which) const; // Returns the name, w/o resolving.
416 int klass_name_index_at(int which) const {
417 return klass_slot_at(which).name_index();
418 }
419
420 Klass* resolved_klass_at(int which) const; // Used by Compiler
421
422 // RedefineClasses() API support:
423 Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
424 void temp_unresolved_klass_at_put(int which, int name_index) {
425 // Used only during constant pool merging for class redefinition. The resolved klass index
426 // will be initialized later by a call to initialize_unresolved_klasses().
427 unresolved_klass_at_put(which, name_index, CPKlassSlot::_temp_resolved_klass_index);
428 }
429
430 jint int_at(int which) {
431 assert(tag_at(which).is_int(), "Corrupted constant pool");
432 return *int_at_addr(which);
433 }
434
435 jlong long_at(int which) {
436 assert(tag_at(which).is_long(), "Corrupted constant pool");
437 // return *long_at_addr(which);
438 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
439 return *((jlong*)&tmp);
440 }
441
442 jfloat float_at(int which) {
443 assert(tag_at(which).is_float(), "Corrupted constant pool");
444 return *float_at_addr(which);
445 }
446
447 jdouble double_at(int which) {
448 assert(tag_at(which).is_double(), "Corrupted constant pool");
449 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
450 return *((jdouble*)&tmp);
451 }
452
453 Symbol* symbol_at(int which) const {
454 assert(tag_at(which).is_utf8(), "Corrupted constant pool");
455 return *symbol_at_addr(which);
456 }
457
458 oop string_at(int which, int obj_index, TRAPS) {
459 constantPoolHandle h_this(THREAD, this);
460 return string_at_impl(h_this, which, obj_index, THREAD);
461 }
462 oop string_at(int which, TRAPS) {
463 int obj_index = cp_to_object_index(which);
464 return string_at(which, obj_index, THREAD);
465 }
466
467 // Version that can be used before string oop array is created.
468 oop uncached_string_at(int which, TRAPS);
469
470 // A "pseudo-string" is an non-string oop that has found its way into
471 // a String entry.
472 // This can happen if the user patches a live
473 // object into a CONSTANT_String entry of an unsafe anonymous class.
474 // Method oops internally created for method handles may also
475 // use pseudo-strings to link themselves to related metaobjects.
476
477 bool is_pseudo_string_at(int which);
478
479 oop pseudo_string_at(int which, int obj_index);
480
481 oop pseudo_string_at(int which);
482
483 void pseudo_string_at_put(int which, int obj_index, oop x) {
484 assert(tag_at(which).is_string(), "Corrupted constant pool");
485 Symbol* sym = unresolved_string_at(which);
486 slot_at_put(which, CPSlot(sym, CPSlot::_pseudo_bit));
487 string_at_put(which, obj_index, x); // this works just fine
488 }
489
490 // only called when we are sure a string entry is already resolved (via an
491 // earlier string_at call.
492 oop resolved_string_at(int which) {
493 assert(tag_at(which).is_string(), "Corrupted constant pool");
494 // Must do an acquire here in case another thread resolved the klass
495 // behind our back, lest we later load stale values thru the oop.
496 // we might want a volatile_obj_at in ObjArrayKlass.
497 int obj_index = cp_to_object_index(which);
498 return resolved_references()->obj_at(obj_index);
499 }
500
501 Symbol* unresolved_string_at(int which) {
502 assert(tag_at(which).is_string(), "Corrupted constant pool");
503 Symbol* sym = slot_at(which).get_symbol();
504 return sym;
505 }
506
507 // Returns an UTF8 for a CONSTANT_String entry at a given index.
508 // UTF8 char* representation was chosen to avoid conversion of
509 // java_lang_Strings at resolved entries into Symbol*s
510 // or vice versa.
511 char* string_at_noresolve(int which);
512
513 jint name_and_type_at(int which) {
514 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
515 return *int_at_addr(which);
516 }
517
518 int method_handle_ref_kind_at(int which) {
519 assert(tag_at(which).is_method_handle() ||
520 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
521 return extract_low_short_from_int(*int_at_addr(which)); // mask out unwanted ref_index bits
522 }
523 int method_handle_index_at(int which) {
524 assert(tag_at(which).is_method_handle() ||
525 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
526 return extract_high_short_from_int(*int_at_addr(which)); // shift out unwanted ref_kind bits
527 }
528 int method_type_index_at(int which) {
529 assert(tag_at(which).is_method_type() ||
530 tag_at(which).is_method_type_in_error(), "Corrupted constant pool");
531 return *int_at_addr(which);
532 }
533
534 // Derived queries:
535 Symbol* method_handle_name_ref_at(int which) {
536 int member = method_handle_index_at(which);
537 return impl_name_ref_at(member, true);
538 }
539 Symbol* method_handle_signature_ref_at(int which) {
540 int member = method_handle_index_at(which);
541 return impl_signature_ref_at(member, true);
542 }
543 int method_handle_klass_index_at(int which) {
544 int member = method_handle_index_at(which);
545 return impl_klass_ref_index_at(member, true);
546 }
547 Symbol* method_type_signature_at(int which) {
548 int sym = method_type_index_at(which);
549 return symbol_at(sym);
550 }
551
552 int bootstrap_name_and_type_ref_index_at(int which) {
553 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
554 return extract_high_short_from_int(*int_at_addr(which));
555 }
556 int bootstrap_methods_attribute_index(int which) {
557 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
558 return extract_low_short_from_int(*int_at_addr(which));
559 }
560 int bootstrap_operand_base(int which) {
561 int bsms_attribute_index = bootstrap_methods_attribute_index(which);
562 return operand_offset_at(operands(), bsms_attribute_index);
563 }
564 // The first part of the operands array consists of an index into the second part.
565 // Extract a 32-bit index value from the first part.
566 static int operand_offset_at(Array<u2>* operands, int bsms_attribute_index) {
567 int n = (bsms_attribute_index * 2);
568 assert(n >= 0 && n+2 <= operands->length(), "oob");
569 // The first 32-bit index points to the beginning of the second part
570 // of the operands array. Make sure this index is in the first part.
571 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
572 operands->at(1)));
573 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
574 int offset = build_int_from_shorts(operands->at(n+0),
575 operands->at(n+1));
576 // The offset itself must point into the second part of the array.
577 assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
578 return offset;
579 }
580 static void operand_offset_at_put(Array<u2>* operands, int bsms_attribute_index, int offset) {
581 int n = bsms_attribute_index * 2;
582 assert(n >= 0 && n+2 <= operands->length(), "oob");
583 operands->at_put(n+0, extract_low_short_from_int(offset));
584 operands->at_put(n+1, extract_high_short_from_int(offset));
585 }
586 static int operand_array_length(Array<u2>* operands) {
587 if (operands == NULL || operands->length() == 0) return 0;
588 int second_part = operand_offset_at(operands, 0);
589 return (second_part / 2);
590 }
591
592 #ifdef ASSERT
593 // operand tuples fit together exactly, end to end
594 static int operand_limit_at(Array<u2>* operands, int bsms_attribute_index) {
595 int nextidx = bsms_attribute_index + 1;
596 if (nextidx == operand_array_length(operands))
597 return operands->length();
598 else
599 return operand_offset_at(operands, nextidx);
600 }
601 int bootstrap_operand_limit(int which) {
602 int bsms_attribute_index = bootstrap_methods_attribute_index(which);
603 return operand_limit_at(operands(), bsms_attribute_index);
604 }
605 #endif //ASSERT
606
607 // Layout of InvokeDynamic and Dynamic bootstrap method specifier
608 // data in second part of operands array. This encodes one record in
609 // the BootstrapMethods attribute. The whole specifier also includes
610 // the name and type information from the main constant pool entry.
611 enum {
612 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
613 _indy_argc_offset = 1, // u2 argc
614 _indy_argv_offset = 2 // u2 argv[argc]
615 };
616
617 // These functions are used in RedefineClasses for CP merge
618
619 int operand_offset_at(int bsms_attribute_index) {
620 assert(0 <= bsms_attribute_index &&
621 bsms_attribute_index < operand_array_length(operands()),
622 "Corrupted CP operands");
623 return operand_offset_at(operands(), bsms_attribute_index);
624 }
625 int operand_bootstrap_method_ref_index_at(int bsms_attribute_index) {
626 int offset = operand_offset_at(bsms_attribute_index);
627 return operands()->at(offset + _indy_bsm_offset);
628 }
629 int operand_argument_count_at(int bsms_attribute_index) {
630 int offset = operand_offset_at(bsms_attribute_index);
631 int argc = operands()->at(offset + _indy_argc_offset);
632 return argc;
633 }
634 int operand_argument_index_at(int bsms_attribute_index, int j) {
635 int offset = operand_offset_at(bsms_attribute_index);
636 return operands()->at(offset + _indy_argv_offset + j);
637 }
638 int operand_next_offset_at(int bsms_attribute_index) {
639 int offset = operand_offset_at(bsms_attribute_index) + _indy_argv_offset
640 + operand_argument_count_at(bsms_attribute_index);
641 return offset;
642 }
643 // Compare a bootstrap specifier data in the operands arrays
644 bool compare_operand_to(int bsms_attribute_index1, const constantPoolHandle& cp2,
645 int bsms_attribute_index2, TRAPS);
646 // Find a bootstrap specifier data in the operands array
647 int find_matching_operand(int bsms_attribute_index, const constantPoolHandle& search_cp,
648 int operands_cur_len, TRAPS);
649 // Resize the operands array with delta_len and delta_size
650 void resize_operands(int delta_len, int delta_size, TRAPS);
651 // Extend the operands array with the length and size of the ext_cp operands
652 void extend_operands(const constantPoolHandle& ext_cp, TRAPS);
653 // Shrink the operands array to a smaller array with new_len length
654 void shrink_operands(int new_len, TRAPS);
655
656 int bootstrap_method_ref_index_at(int which) {
657 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
658 int op_base = bootstrap_operand_base(which);
659 return operands()->at(op_base + _indy_bsm_offset);
660 }
661 int bootstrap_argument_count_at(int which) {
662 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
663 int op_base = bootstrap_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 = bootstrap_operand_limit(which));
667 assert(end_offset == next_offset, "matched ending");
668 return argc;
669 }
670 int bootstrap_argument_index_at(int which, int j) {
671 int op_base = bootstrap_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 archive_resolved_references(Thread *THREAD) NOT_CDS_JAVA_HEAP_RETURN;
719 void resolve_class_constants(TRAPS) NOT_CDS_JAVA_HEAP_RETURN;
720 void remove_unshareable_info();
721 void restore_unshareable_info(TRAPS);
722 // The ConstantPool vtable is restored by this call when the ConstantPool is
723 // in the shared archive. See patch_klass_vtables() in metaspaceShared.cpp for
724 // all the gory details. SA, dtrace and pstack helpers distinguish metadata
725 // by their vtable.
726 void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); }
727
728 private:
729 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
730 public:
731
732 // Get the tag for a constant, which may involve a constant dynamic
733 constantTag constant_tag_at(int which);
734 // Get the basic type for a constant, which may involve a constant dynamic
735 BasicType basic_type_for_constant_at(int which);
736
737 // Resolve late bound constants.
738 oop resolve_constant_at(int index, TRAPS) {
739 constantPoolHandle h_this(THREAD, this);
740 return resolve_constant_at_impl(h_this, index, _no_index_sentinel, NULL, THREAD);
741 }
742
743 oop resolve_cached_constant_at(int cache_index, TRAPS) {
744 constantPoolHandle h_this(THREAD, this);
745 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, NULL, THREAD);
746 }
747
748 oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
749 constantPoolHandle h_this(THREAD, this);
750 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, NULL, THREAD);
751 }
752
753 oop find_cached_constant_at(int pool_index, bool& found_it, TRAPS) {
754 constantPoolHandle h_this(THREAD, this);
755 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, &found_it, THREAD);
756 }
757
758 oop resolve_bootstrap_specifier_at(int index, TRAPS) {
759 constantPoolHandle h_this(THREAD, this);
760 return resolve_bootstrap_specifier_at_impl(h_this, index, THREAD);
761 }
762
763 void copy_bootstrap_arguments_at(int index,
764 int start_arg, int end_arg,
765 objArrayHandle info, int pos,
766 bool must_resolve, Handle if_not_available, TRAPS) {
767 constantPoolHandle h_this(THREAD, this);
768 copy_bootstrap_arguments_at_impl(h_this, index, start_arg, end_arg,
769 info, pos, must_resolve, if_not_available, THREAD);
770 }
771
772 // Klass name matches name at offset
773 bool klass_name_at_matches(const InstanceKlass* k, int which);
774
775 // Sizing
776 int length() const { return _length; }
777 void set_length(int length) { _length = length; }
778
779 // Tells whether index is within bounds.
780 bool is_within_bounds(int index) const {
781 return 0 <= index && index < length();
782 }
783
784 // Sizing (in words)
785 static int header_size() {
786 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize;
787 }
788 static int size(int length) { return align_metadata_size(header_size() + length); }
789 int size() const { return size(length()); }
790 #if INCLUDE_SERVICES
791 void collect_statistics(KlassSizeStats *sz) const;
792 #endif
793
794 // ConstantPools should be stored in the read-only region of CDS archive.
795 static bool is_read_only_by_default() { return true; }
796
797 friend class ClassFileParser;
798 friend class SystemDictionary;
799
800 // Used by CDS. These classes need to access the private ConstantPool() constructor.
801 template <class T> friend class CppVtableTesterA;
802 template <class T> friend class CppVtableTesterB;
803 template <class T> friend class CppVtableCloner;
804
805 // Used by compiler to prevent classloading.
806 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which);
807 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
808 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
809 static bool has_local_signature_at_if_loaded (const constantPoolHandle& this_cp, int which);
810 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which);
811
812 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
813 // future by other Java code. These take constant pool indices rather than
814 // constant pool cache indices as do the peer methods above.
815 Symbol* uncached_klass_ref_at_noresolve(int which);
816 Symbol* uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); }
817 Symbol* uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); }
818 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); }
819 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); }
820
821 // Sharing
822 int pre_resolve_shared_klasses(TRAPS);
823
824 // Debugging
825 const char* printable_name_at(int which) PRODUCT_RETURN0;
826
827 #ifdef ASSERT
828 enum { CPCACHE_INDEX_TAG = 0x10000 }; // helps keep CP cache indices distinct from CP indices
829 #else
830 enum { CPCACHE_INDEX_TAG = 0 }; // in product mode, this zero value is a no-op
831 #endif //ASSERT
832
833 static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) {
834 if (invokedynamic_ok && is_invokedynamic_index(raw_index))
835 return decode_invokedynamic_index(raw_index);
836 else
837 return raw_index - CPCACHE_INDEX_TAG;
838 }
839
840 private:
841
842 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); }
843 Array<u2>* reference_map() const { return (_cache == NULL) ? NULL : _cache->reference_map(); }
844 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); }
845
846 // patch JSR 292 resolved references after the class is linked.
847 void patch_resolved_references(GrowableArray<Handle>* cp_patches);
848
849 Symbol* impl_name_ref_at(int which, bool uncached);
850 Symbol* impl_signature_ref_at(int which, bool uncached);
851
852 int impl_klass_ref_index_at(int which, bool uncached);
853 int impl_name_and_type_ref_index_at(int which, bool uncached);
854 constantTag impl_tag_ref_at(int which, bool uncached);
855
856 // Used while constructing constant pool (only by ClassFileParser)
857 jint klass_index_at(int which) {
858 assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
859 return *int_at_addr(which);
860 }
861
862 jint string_index_at(int which) {
863 assert(tag_at(which).is_string_index(), "Corrupted constant pool");
864 return *int_at_addr(which);
865 }
866
867 // Performs the LinkResolver checks
868 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS);
869
870 // Implementation of methods that needs an exposed 'this' pointer, in order to
871 // handle GC while executing the method
872 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int which,
873 bool save_resolution_error, TRAPS);
874 static oop string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS);
875
876 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k);
877
878 // Resolve string constants (to prevent allocation during compilation)
879 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS);
880
881 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int index, int cache_index,
882 bool* status_return, TRAPS);
883 static oop resolve_bootstrap_specifier_at_impl(const constantPoolHandle& this_cp, int index, TRAPS);
884 static void copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int index,
885 int start_arg, int end_arg,
886 objArrayHandle info, int pos,
887 bool must_resolve, Handle if_not_available, TRAPS);
888
889 // Exception handling
890 static Symbol* exception_message(const constantPoolHandle& this_cp, int which, constantTag tag, oop pending_exception);
891 static void save_and_throw_exception(const constantPoolHandle& this_cp, int which, constantTag tag, TRAPS);
892
893 public:
894 // Exception handling
895 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS);
896
897 // Merging ConstantPool* support:
898 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2, TRAPS);
899 void copy_cp_to(int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS) {
900 constantPoolHandle h_this(THREAD, this);
901 copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
902 }
903 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
904 static void copy_entry_to(const constantPoolHandle& from_cp, int from_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
905 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS);
906 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp, TRAPS);
907 int version() const { return _saved._version; }
908 void set_version(int version) { _saved._version = version; }
909 void increment_and_save_version(int version) {
910 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow
911 }
912
913 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
914 int resolved_reference_length() const { return _saved._resolved_reference_length; }
915
916 // Decrease ref counts of symbols that are in the constant pool
917 // when the holder class is unloaded
918 void unreference_symbols();
919
920 // Deallocate constant pool for RedefineClasses
921 void deallocate_contents(ClassLoaderData* loader_data);
922 void release_C_heap_structures();
923
924 // JVMTI accesss - GetConstantPool, RetransformClasses, ...
925 friend class JvmtiConstantPoolReconstituter;
926
927 private:
928 jint cpool_entry_size(jint idx);
929 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
930
931 // Copy cpool bytes into byte array.
932 // Returns:
933 // int > 0, count of the raw cpool bytes that have been copied
934 // 0, OutOfMemory error
935 // -1, Internal error
936 int copy_cpool_bytes(int cpool_size,
937 SymbolHashMap* tbl,
938 unsigned char *bytes);
939
940 public:
941 // Verify
942 void verify_on(outputStream* st);
943
944 // Printing
945 void print_on(outputStream* st) const;
946 void print_value_on(outputStream* st) const;
947 void print_entry_on(int index, outputStream* st);
948
949 const char* internal_name() const { return "{constant pool}"; }
950 };
951
952 class SymbolHashMapEntry : public CHeapObj<mtSymbol> {
953 private:
954 unsigned int _hash; // 32-bit hash for item
955 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket
956 Symbol* _symbol; // 1-st part of the mapping: symbol => value
957 u2 _value; // 2-nd part of the mapping: symbol => value
958
959 public:
960 unsigned int hash() const { return _hash; }
961 void set_hash(unsigned int hash) { _hash = hash; }
962
963 SymbolHashMapEntry* next() const { return _next; }
964 void set_next(SymbolHashMapEntry* next) { _next = next; }
965
966 Symbol* symbol() const { return _symbol; }
967 void set_symbol(Symbol* sym) { _symbol = sym; }
968
969 u2 value() const { return _value; }
970 void set_value(u2 value) { _value = value; }
971
972 SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
973 : _hash(hash), _next(NULL), _symbol(symbol), _value(value) {}
974
975 }; // End SymbolHashMapEntry class
976
977
978 class SymbolHashMapBucket : public CHeapObj<mtSymbol> {
979
980 private:
981 SymbolHashMapEntry* _entry;
982
983 public:
984 SymbolHashMapEntry* entry() const { return _entry; }
985 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
986 void clear() { _entry = NULL; }
987
988 }; // End SymbolHashMapBucket class
989
990
991 class SymbolHashMap: public CHeapObj<mtSymbol> {
992
993 private:
994 // Default number of entries in the table
995 enum SymbolHashMap_Constants {
996 _Def_HashMap_Size = 256
997 };
998
999 int _table_size;
1000 SymbolHashMapBucket* _buckets;
1001
1002 void initialize_table(int table_size);
1003
1004 public:
1005
1006 int table_size() const { return _table_size; }
1007
1008 SymbolHashMap() { initialize_table(_Def_HashMap_Size); }
1009 SymbolHashMap(int table_size) { initialize_table(table_size); }
1010
1011 // hash P(31) from Kernighan & Ritchie
1012 static unsigned int compute_hash(const char* str, int len) {
1013 unsigned int hash = 0;
1014 while (len-- > 0) {
1015 hash = 31*hash + (unsigned) *str;
1016 str++;
1017 }
1018 return hash;
1019 }
1020
1021 SymbolHashMapEntry* bucket(int i) {
1022 return _buckets[i].entry();
1023 }
1024
1025 void add_entry(Symbol* sym, u2 value);
1026 SymbolHashMapEntry* find_entry(Symbol* sym);
1027
1028 u2 symbol_to_value(Symbol* sym) {
1029 SymbolHashMapEntry *entry = find_entry(sym);
1030 return (entry == NULL) ? 0 : entry->value();
1031 }
1032
1033 ~SymbolHashMap();
1034 }; // End SymbolHashMap class
1035
1036 #endif // SHARE_OOPS_CONSTANTPOOL_HPP