1 /*
2 * Copyright (c) 1997, 2025, 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
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 "runtime/javaThread.hpp"
37 #include "utilities/align.hpp"
38 #include "utilities/bytes.hpp"
39 #include "utilities/constantTag.hpp"
40 #include "utilities/macros.hpp"
41 #include "utilities/resourceHash.hpp"
42
43 // A ConstantPool is an array containing class constants as described in the
44 // class file.
45 //
46 // Most of the constant pool entries are written during class parsing, which
47 // is safe. For klass types, the constant pool entry is
48 // modified when the entry is resolved. If a klass constant pool
49 // entry is read without a lock, only the resolved state guarantees that
50 // the entry in the constant pool is a klass object and not a Symbol*.
51
52 // This represents a JVM_CONSTANT_Class, JVM_CONSTANT_UnresolvedClass, or
53 // JVM_CONSTANT_UnresolvedClassInError slot in the constant pool.
54 class CPKlassSlot {
55 // cp->symbol_at(_name_index) gives the name of the class.
56 int _name_index;
57
58 // cp->_resolved_klasses->at(_resolved_klass_index) gives the Klass* for the class.
59 int _resolved_klass_index;
60 public:
61 enum {
62 // This is used during constant pool merging where the resolved klass index is
63 // not yet known, and will be computed at a later stage (during a call to
64 // initialize_unresolved_klasses()).
65 _temp_resolved_klass_index = 0xffff
66 };
67 CPKlassSlot(int n, int rk) {
68 _name_index = n;
69 _resolved_klass_index = rk;
70 }
71 int name_index() const {
72 return _name_index;
73 }
74 int resolved_klass_index() const {
75 assert(_resolved_klass_index != _temp_resolved_klass_index, "constant pool merging was incomplete");
76 return _resolved_klass_index;
77 }
78 };
79
80 class ConstantPool : public Metadata {
81 friend class VMStructs;
82 friend class JVMCIVMStructs;
83 friend class BytecodeInterpreter; // Directly extracts a klass in the pool for fast instanceof/checkcast
84 friend class Universe; // For null constructor
85 friend class AOTConstantPoolResolver;
86 private:
87 // If you add a new field that points to any metaspace object, you
88 // must add this field to ConstantPool::metaspace_pointers_do().
89 Array<u1>* _tags; // the tag array describing the constant pool's contents
90 ConstantPoolCache* _cache; // the cache holding interpreter runtime information
91 InstanceKlass* _pool_holder; // the corresponding class
92 Array<u2>* _operands; // for variable-sized (InvokeDynamic) nodes, usually empty
93
94 // Consider using an array of compressed klass pointers to
95 // save space on 64-bit platforms.
96 Array<Klass*>* _resolved_klasses;
97
98 u2 _major_version; // major version number of class file
99 u2 _minor_version; // minor version number of class file
100
101 // Constant pool index to the utf8 entry of the Generic signature,
102 // or 0 if none.
103 u2 _generic_signature_index;
104 // Constant pool index to the utf8 entry for the name of source file
105 // containing this klass, 0 if not specified.
106 u2 _source_file_name_index;
107
108 enum {
109 _has_preresolution = 1, // Flags
110 _on_stack = 2,
111 _is_shared = 4,
112 _has_dynamic_constant = 8,
113 _is_for_method_handle_intrinsic = 16
114 };
115
116 u2 _flags; // old fashioned bit twiddling
117
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 cp_index, jbyte t) { tags()->at_put(cp_index, t); }
129 void release_tag_at_put(int cp_index, jbyte t) { tags()->release_at_put(cp_index, t); }
130
131 u1* tag_addr_at(int cp_index) const { return tags()->adr_at(cp_index); }
132
133 void set_operands(Array<u2>* operands) { _operands = operands; }
134
135 u2 flags() const { return _flags; }
136 void set_flags(u2 f) { _flags = f; }
137
138 private:
139 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
140
141 intptr_t* obj_at_addr(int cp_index) const {
142 assert(is_within_bounds(cp_index), "index out of bounds");
143 return (intptr_t*) &base()[cp_index];
144 }
145
146 jint* int_at_addr(int cp_index) const {
147 assert(is_within_bounds(cp_index), "index out of bounds");
148 return (jint*) &base()[cp_index];
149 }
150
151 jlong* long_at_addr(int cp_index) const {
152 assert(is_within_bounds(cp_index), "index out of bounds");
153 return (jlong*) &base()[cp_index];
154 }
155
156 jfloat* float_at_addr(int cp_index) const {
157 assert(is_within_bounds(cp_index), "index out of bounds");
158 return (jfloat*) &base()[cp_index];
159 }
160
161 jdouble* double_at_addr(int cp_index) const {
162 assert(is_within_bounds(cp_index), "index out of bounds");
163 return (jdouble*) &base()[cp_index];
164 }
165
166 ConstantPool(Array<u1>* tags);
167 ConstantPool();
168 public:
169 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
170
171 virtual bool is_constantPool() const { return true; }
172
173 Array<u1>* tags() const { return _tags; }
174 Array<u2>* operands() const { return _operands; }
175
176 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; }
177 void set_has_preresolution() {
178 assert(!is_shared(), "should never be called on shared ConstantPools");
179 _flags |= _has_preresolution;
180 }
181
182 // minor and major version numbers of class file
183 u2 major_version() const { return _major_version; }
184 void set_major_version(u2 major_version) { _major_version = major_version; }
185 u2 minor_version() const { return _minor_version; }
186 void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
187
188 // generics support
189 Symbol* generic_signature() const {
190 return (_generic_signature_index == 0) ?
191 nullptr : symbol_at(_generic_signature_index);
192 }
193 u2 generic_signature_index() const { return _generic_signature_index; }
194 void set_generic_signature_index(u2 sig_index) { _generic_signature_index = sig_index; }
195
196 // source file name
197 Symbol* source_file_name() const {
198 return (_source_file_name_index == 0) ?
199 nullptr : symbol_at(_source_file_name_index);
200 }
201 u2 source_file_name_index() const { return _source_file_name_index; }
202 void set_source_file_name_index(u2 sourcefile_index) { _source_file_name_index = sourcefile_index; }
203
204 void copy_fields(const ConstantPool* orig);
205
206 // Redefine classes support. If a method referring to this constant pool
207 // is on the executing stack, or as a handle in vm code, this constant pool
208 // can't be removed from the set of previous versions saved in the instance
209 // class.
210 bool on_stack() const;
211 bool is_maybe_on_stack() const;
212 void set_on_stack(const bool value);
213
214 // Faster than MetaspaceObj::is_shared() - used by set_on_stack()
215 bool is_shared() const { return (_flags & _is_shared) != 0; }
216
217 bool has_dynamic_constant() const { return (_flags & _has_dynamic_constant) != 0; }
218 void set_has_dynamic_constant() { _flags |= _has_dynamic_constant; }
219
220 bool is_for_method_handle_intrinsic() const { return (_flags & _is_for_method_handle_intrinsic) != 0; }
221 void set_is_for_method_handle_intrinsic() { _flags |= _is_for_method_handle_intrinsic; }
222
223 // Klass holding pool
224 InstanceKlass* pool_holder() const { return _pool_holder; }
225 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; }
226 InstanceKlass** pool_holder_addr() { return &_pool_holder; }
227
228 // Interpreter runtime support
229 ConstantPoolCache* cache() const { return _cache; }
230 void set_cache(ConstantPoolCache* cache){ _cache = cache; }
231
232 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
233 virtual MetaspaceObj::Type type() const { return ConstantPoolType; }
234
235 // Create object cache in the constant pool
236 void initialize_resolved_references(ClassLoaderData* loader_data,
237 const intStack& reference_map,
238 int constant_pool_map_length,
239 TRAPS);
240
241 // resolved strings, methodHandles and callsite objects from the constant pool
242 objArrayOop resolved_references() const;
243 objArrayOop resolved_references_or_null() const;
244 oop resolved_reference_at(int obj_index) const;
245 oop set_resolved_reference_at(int index, oop new_value);
246
247 // mapping resolved object array indexes to cp indexes and back.
248 int object_to_cp_index(int index) { return reference_map()->at(index); }
249 int cp_to_object_index(int index);
250
251 void set_resolved_klasses(Array<Klass*>* rk) { _resolved_klasses = rk; }
252 Array<Klass*>* resolved_klasses() const { return _resolved_klasses; }
253 void allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS);
254 void initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS);
255
256 // Given the per-instruction index of an indy instruction, report the
257 // main constant pool entry for its bootstrap specifier.
258 // From there, uncached_name/signature_ref_at will get the name/type.
259 inline u2 invokedynamic_bootstrap_ref_index_at(int indy_index) const;
260
261 // Assembly code support
262 static ByteSize tags_offset() { return byte_offset_of(ConstantPool, _tags); }
263 static ByteSize cache_offset() { return byte_offset_of(ConstantPool, _cache); }
264 static ByteSize pool_holder_offset() { return byte_offset_of(ConstantPool, _pool_holder); }
265 static ByteSize resolved_klasses_offset() { return byte_offset_of(ConstantPool, _resolved_klasses); }
266
267 // Storing constants
268
269 // For temporary use while constructing constant pool
270 void klass_index_at_put(int cp_index, int name_index) {
271 tag_at_put(cp_index, JVM_CONSTANT_ClassIndex);
272 *int_at_addr(cp_index) = name_index;
273 }
274
275 // Hidden class support:
276 void klass_at_put(int class_index, Klass* k);
277
278 void unresolved_klass_at_put(int cp_index, int name_index, int resolved_klass_index) {
279 release_tag_at_put(cp_index, 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(cp_index) =
284 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
285 }
286
287 void method_handle_index_at_put(int cp_index, int ref_kind, int ref_index) {
288 tag_at_put(cp_index, JVM_CONSTANT_MethodHandle);
289 *int_at_addr(cp_index) = ((jint) ref_index<<16) | ref_kind;
290 }
291
292 void method_type_index_at_put(int cp_index, int ref_index) {
293 tag_at_put(cp_index, JVM_CONSTANT_MethodType);
294 *int_at_addr(cp_index) = ref_index;
295 }
296
297 void dynamic_constant_at_put(int cp_index, int bsms_attribute_index, int name_and_type_index) {
298 tag_at_put(cp_index, JVM_CONSTANT_Dynamic);
299 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
300 }
301
302 void invoke_dynamic_at_put(int cp_index, int bsms_attribute_index, int name_and_type_index) {
303 tag_at_put(cp_index, JVM_CONSTANT_InvokeDynamic);
304 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
305 }
306
307 void unresolved_string_at_put(int cp_index, Symbol* s) {
308 assert(s->refcount() != 0, "should have nonzero refcount");
309 // Note that release_tag_at_put is not needed here because this is called only
310 // when constructing a ConstantPool in a single thread, with no possibility
311 // of concurrent access.
312 tag_at_put(cp_index, JVM_CONSTANT_String);
313 *symbol_at_addr(cp_index) = s;
314 }
315
316 void int_at_put(int cp_index, jint i) {
317 tag_at_put(cp_index, JVM_CONSTANT_Integer);
318 *int_at_addr(cp_index) = i;
319 }
320
321 void long_at_put(int cp_index, jlong l) {
322 tag_at_put(cp_index, JVM_CONSTANT_Long);
323 // *long_at_addr(which) = l;
324 Bytes::put_native_u8((address)long_at_addr(cp_index), *((u8*) &l));
325 }
326
327 void float_at_put(int cp_index, jfloat f) {
328 tag_at_put(cp_index, JVM_CONSTANT_Float);
329 *float_at_addr(cp_index) = f;
330 }
331
332 void double_at_put(int cp_index, jdouble d) {
333 tag_at_put(cp_index, JVM_CONSTANT_Double);
334 // *double_at_addr(which) = d;
335 // u8 temp = *(u8*) &d;
336 Bytes::put_native_u8((address) double_at_addr(cp_index), *((u8*) &d));
337 }
338
339 Symbol** symbol_at_addr(int cp_index) const {
340 assert(is_within_bounds(cp_index), "index out of bounds");
341 return (Symbol**) &base()[cp_index];
342 }
343
344 void symbol_at_put(int cp_index, Symbol* s) {
345 assert(s->refcount() != 0, "should have nonzero refcount");
346 tag_at_put(cp_index, JVM_CONSTANT_Utf8);
347 *symbol_at_addr(cp_index) = s;
348 }
349
350 void string_at_put(int obj_index, oop str);
351
352 // For temporary use while constructing constant pool
353 void string_index_at_put(int cp_index, int string_index) {
354 tag_at_put(cp_index, JVM_CONSTANT_StringIndex);
355 *int_at_addr(cp_index) = string_index;
356 }
357
358 void field_at_put(int cp_index, int class_index, int name_and_type_index) {
359 tag_at_put(cp_index, JVM_CONSTANT_Fieldref);
360 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index;
361 }
362
363 void method_at_put(int cp_index, int class_index, int name_and_type_index) {
364 tag_at_put(cp_index, JVM_CONSTANT_Methodref);
365 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index;
366 }
367
368 void interface_method_at_put(int cp_index, int class_index, int name_and_type_index) {
369 tag_at_put(cp_index, JVM_CONSTANT_InterfaceMethodref);
370 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
371 }
372
373 void name_and_type_at_put(int cp_index, int name_index, int signature_index) {
374 tag_at_put(cp_index, JVM_CONSTANT_NameAndType);
375 *int_at_addr(cp_index) = ((jint) signature_index<<16) | name_index; // Not so nice
376 }
377
378 // Tag query
379
380 constantTag tag_at(int cp_index) const { return (constantTag)tags()->at_acquire(cp_index); }
381
382 // Fetching constants
383
384 Klass* klass_at(int cp_index, TRAPS) {
385 constantPoolHandle h_this(THREAD, this);
386 return klass_at_impl(h_this, cp_index, THREAD);
387 }
388
389 CPKlassSlot klass_slot_at(int cp_index) const {
390 assert(tag_at(cp_index).is_unresolved_klass() || tag_at(cp_index).is_klass(),
391 "Corrupted constant pool");
392 int value = *int_at_addr(cp_index);
393 int name_index = extract_high_short_from_int(value);
394 int resolved_klass_index = extract_low_short_from_int(value);
395 return CPKlassSlot(name_index, resolved_klass_index);
396 }
397
398 Symbol* klass_name_at(int cp_index) const; // Returns the name, w/o resolving.
399 int klass_name_index_at(int cp_index) const {
400 return klass_slot_at(cp_index).name_index();
401 }
402
403 Klass* resolved_klass_at(int cp_index) const; // Used by Compiler
404
405 // RedefineClasses() API support:
406 Symbol* klass_at_noresolve(int cp_index) { return klass_name_at(cp_index); }
407 void temp_unresolved_klass_at_put(int cp_index, int name_index) {
408 // Used only during constant pool merging for class redefinition. The resolved klass index
409 // will be initialized later by a call to initialize_unresolved_klasses().
410 unresolved_klass_at_put(cp_index, name_index, CPKlassSlot::_temp_resolved_klass_index);
411 }
412
413 jint int_at(int cp_index) const {
414 assert(tag_at(cp_index).is_int(), "Corrupted constant pool");
415 return *int_at_addr(cp_index);
416 }
417
418 jlong long_at(int cp_index) {
419 assert(tag_at(cp_index).is_long(), "Corrupted constant pool");
420 // return *long_at_addr(cp_index);
421 u8 tmp = Bytes::get_native_u8((address)&base()[cp_index]);
422 return *((jlong*)&tmp);
423 }
424
425 jfloat float_at(int cp_index) {
426 assert(tag_at(cp_index).is_float(), "Corrupted constant pool");
427 return *float_at_addr(cp_index);
428 }
429
430 jdouble double_at(int cp_index) {
431 assert(tag_at(cp_index).is_double(), "Corrupted constant pool");
432 u8 tmp = Bytes::get_native_u8((address)&base()[cp_index]);
433 return *((jdouble*)&tmp);
434 }
435
436 Symbol* symbol_at(int cp_index) const {
437 assert(tag_at(cp_index).is_utf8(), "Corrupted constant pool");
438 return *symbol_at_addr(cp_index);
439 }
440
441 oop string_at(int cp_index, int obj_index, TRAPS) {
442 constantPoolHandle h_this(THREAD, this);
443 return string_at_impl(h_this, cp_index, obj_index, THREAD);
444 }
445 oop string_at(int cp_index, TRAPS) {
446 int obj_index = cp_to_object_index(cp_index);
447 return string_at(cp_index, obj_index, THREAD);
448 }
449
450 // Version that can be used before string oop array is created.
451 oop uncached_string_at(int cp_index, TRAPS);
452
453 // only called when we are sure a string entry is already resolved (via an
454 // earlier string_at call.
455 oop resolved_string_at(int cp_index) {
456 assert(tag_at(cp_index).is_string(), "Corrupted constant pool");
457 // Must do an acquire here in case another thread resolved the klass
458 // behind our back, lest we later load stale values thru the oop.
459 // we might want a volatile_obj_at in ObjArrayKlass.
460 int obj_index = cp_to_object_index(cp_index);
461 return resolved_reference_at(obj_index);
462 }
463
464 Symbol* unresolved_string_at(int cp_index) {
465 assert(tag_at(cp_index).is_string(), "Corrupted constant pool");
466 return *symbol_at_addr(cp_index);
467 }
468
469 // Returns an UTF8 for a CONSTANT_String entry at a given index.
470 // UTF8 char* representation was chosen to avoid conversion of
471 // java_lang_Strings at resolved entries into Symbol*s
472 // or vice versa.
473 char* string_at_noresolve(int cp_index);
474
475 jint name_and_type_at(int cp_index) {
476 assert(tag_at(cp_index).is_name_and_type(), "Corrupted constant pool");
477 return *int_at_addr(cp_index);
478 }
479
480 int method_handle_ref_kind_at(int cp_index) {
481 assert(tag_at(cp_index).is_method_handle() ||
482 tag_at(cp_index).is_method_handle_in_error(), "Corrupted constant pool");
483 return extract_low_short_from_int(*int_at_addr(cp_index)); // mask out unwanted ref_index bits
484 }
485 int method_handle_index_at(int cp_index) {
486 assert(tag_at(cp_index).is_method_handle() ||
487 tag_at(cp_index).is_method_handle_in_error(), "Corrupted constant pool");
488 return extract_high_short_from_int(*int_at_addr(cp_index)); // shift out unwanted ref_kind bits
489 }
490 int method_type_index_at(int cp_index) {
491 assert(tag_at(cp_index).is_method_type() ||
492 tag_at(cp_index).is_method_type_in_error(), "Corrupted constant pool");
493 return *int_at_addr(cp_index);
494 }
495
496 // Derived queries:
497 Symbol* method_handle_name_ref_at(int cp_index) {
498 int member = method_handle_index_at(cp_index);
499 return uncached_name_ref_at(member);
500 }
501 Symbol* method_handle_signature_ref_at(int cp_index) {
502 int member = method_handle_index_at(cp_index);
503 return uncached_signature_ref_at(member);
504 }
505 u2 method_handle_klass_index_at(int cp_index) {
506 int member = method_handle_index_at(cp_index);
507 return uncached_klass_ref_index_at(member);
508 }
509 Symbol* method_type_signature_at(int cp_index) {
510 int sym = method_type_index_at(cp_index);
511 return symbol_at(sym);
512 }
513
514 u2 bootstrap_name_and_type_ref_index_at(int cp_index) {
515 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
516 return extract_high_short_from_int(*int_at_addr(cp_index));
517 }
518 u2 bootstrap_methods_attribute_index(int cp_index) {
519 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
520 return extract_low_short_from_int(*int_at_addr(cp_index));
521 }
522 int bootstrap_operand_base(int cp_index) {
523 int bsms_attribute_index = bootstrap_methods_attribute_index(cp_index);
524 return operand_offset_at(operands(), bsms_attribute_index);
525 }
526 // The first part of the operands array consists of an index into the second part.
527 // Extract a 32-bit index value from the first part.
528 static int operand_offset_at(Array<u2>* operands, int bsms_attribute_index) {
529 int n = (bsms_attribute_index * 2);
530 assert(n >= 0 && n+2 <= operands->length(), "oob");
531 // The first 32-bit index points to the beginning of the second part
532 // of the operands array. Make sure this index is in the first part.
533 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
534 operands->at(1)));
535 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
536 int offset = build_int_from_shorts(operands->at(n+0),
537 operands->at(n+1));
538 // The offset itself must point into the second part of the array.
539 assert(offset == 0 || (offset >= second_part && offset <= operands->length()), "oob (3)");
540 return offset;
541 }
542 static void operand_offset_at_put(Array<u2>* operands, int bsms_attribute_index, int offset) {
543 int n = bsms_attribute_index * 2;
544 assert(n >= 0 && n+2 <= operands->length(), "oob");
545 operands->at_put(n+0, extract_low_short_from_int(offset));
546 operands->at_put(n+1, extract_high_short_from_int(offset));
547 }
548 static int operand_array_length(Array<u2>* operands) {
549 if (operands == nullptr || operands->length() == 0) return 0;
550 int second_part = operand_offset_at(operands, 0);
551 return (second_part / 2);
552 }
553
554 #ifdef ASSERT
555 // operand tuples fit together exactly, end to end
556 static int operand_limit_at(Array<u2>* operands, int bsms_attribute_index) {
557 int nextidx = bsms_attribute_index + 1;
558 if (nextidx == operand_array_length(operands))
559 return operands->length();
560 else
561 return operand_offset_at(operands, nextidx);
562 }
563 int bootstrap_operand_limit(int cp_index) {
564 int bsms_attribute_index = bootstrap_methods_attribute_index(cp_index);
565 return operand_limit_at(operands(), bsms_attribute_index);
566 }
567 #endif //ASSERT
568
569 // Layout of InvokeDynamic and Dynamic bootstrap method specifier
570 // data in second part of operands array. This encodes one record in
571 // the BootstrapMethods attribute. The whole specifier also includes
572 // the name and type information from the main constant pool entry.
573 enum {
574 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
575 _indy_argc_offset = 1, // u2 argc
576 _indy_argv_offset = 2 // u2 argv[argc]
577 };
578
579 // These functions are used in RedefineClasses for CP merge
580
581 int operand_offset_at(int bsms_attribute_index) {
582 assert(0 <= bsms_attribute_index &&
583 bsms_attribute_index < operand_array_length(operands()),
584 "Corrupted CP operands");
585 return operand_offset_at(operands(), bsms_attribute_index);
586 }
587 u2 operand_bootstrap_method_ref_index_at(int bsms_attribute_index) {
588 int offset = operand_offset_at(bsms_attribute_index);
589 return operands()->at(offset + _indy_bsm_offset);
590 }
591 u2 operand_argument_count_at(int bsms_attribute_index) {
592 int offset = operand_offset_at(bsms_attribute_index);
593 u2 argc = operands()->at(offset + _indy_argc_offset);
594 return argc;
595 }
596 u2 operand_argument_index_at(int bsms_attribute_index, int j) {
597 int offset = operand_offset_at(bsms_attribute_index);
598 return operands()->at(offset + _indy_argv_offset + j);
599 }
600 int operand_next_offset_at(int bsms_attribute_index) {
601 int offset = operand_offset_at(bsms_attribute_index) + _indy_argv_offset
602 + operand_argument_count_at(bsms_attribute_index);
603 return offset;
604 }
605 // Compare a bootstrap specifier data in the operands arrays
606 bool compare_operand_to(int bsms_attribute_index1, const constantPoolHandle& cp2,
607 int bsms_attribute_index2);
608 // Find a bootstrap specifier data in the operands array
609 int find_matching_operand(int bsms_attribute_index, const constantPoolHandle& search_cp,
610 int operands_cur_len);
611 // Resize the operands array with delta_len and delta_size
612 void resize_operands(int delta_len, int delta_size, TRAPS);
613 // Extend the operands array with the length and size of the ext_cp operands
614 void extend_operands(const constantPoolHandle& ext_cp, TRAPS);
615 // Shrink the operands array to a smaller array with new_len length
616 void shrink_operands(int new_len, TRAPS);
617
618 u2 bootstrap_method_ref_index_at(int cp_index) {
619 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
620 int op_base = bootstrap_operand_base(cp_index);
621 return operands()->at(op_base + _indy_bsm_offset);
622 }
623 u2 bootstrap_argument_count_at(int cp_index) {
624 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
625 int op_base = bootstrap_operand_base(cp_index);
626 u2 argc = operands()->at(op_base + _indy_argc_offset);
627 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
628 int next_offset = bootstrap_operand_limit(cp_index));
629 assert(end_offset == next_offset, "matched ending");
630 return argc;
631 }
632 u2 bootstrap_argument_index_at(int cp_index, int j) {
633 int op_base = bootstrap_operand_base(cp_index);
634 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
635 assert((uint)j < (uint)argc, "oob");
636 return operands()->at(op_base + _indy_argv_offset + j);
637 }
638
639 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
640 // name_and_type_ref_index_at) all expect to be passed indices obtained
641 // directly from the bytecode.
642 // If the indices are meant to refer to fields or methods, they are
643 // actually rewritten indices that point to entries in their respective structures
644 // i.e. ResolvedMethodEntries or ResolvedFieldEntries.
645 // The routine to_cp_index manages the adjustment
646 // of these values back to constant pool indices.
647
648 // There are also "uncached" versions which do not adjust the operand index; see below.
649
650 // Lookup for entries consisting of (klass_index, name_and_type index)
651 Klass* klass_ref_at(int which, Bytecodes::Code code, TRAPS);
652 Symbol* klass_ref_at_noresolve(int which, Bytecodes::Code code);
653 Symbol* name_ref_at(int which, Bytecodes::Code code) {
654 int name_index = name_ref_index_at(name_and_type_ref_index_at(which, code));
655 return symbol_at(name_index);
656 }
657 Symbol* signature_ref_at(int which, Bytecodes::Code code) {
658 int signature_index = signature_ref_index_at(name_and_type_ref_index_at(which, code));
659 return symbol_at(signature_index);
660 }
661
662 u2 klass_ref_index_at(int which, Bytecodes::Code code);
663 u2 name_and_type_ref_index_at(int which, Bytecodes::Code code);
664
665 constantTag tag_ref_at(int cp_cache_index, Bytecodes::Code code);
666
667 int to_cp_index(int which, Bytecodes::Code code);
668
669 bool is_resolved(int which, Bytecodes::Code code);
670
671 // Lookup for entries consisting of (name_index, signature_index)
672 u2 name_ref_index_at(int cp_index); // == low-order jshort of name_and_type_at(cp_index)
673 u2 signature_ref_index_at(int cp_index); // == high-order jshort of name_and_type_at(cp_index)
674
675 BasicType basic_type_for_signature_at(int cp_index) const;
676
677 // Resolve string constants (to prevent allocation during compilation)
678 void resolve_string_constants(TRAPS) {
679 constantPoolHandle h_this(THREAD, this);
680 resolve_string_constants_impl(h_this, CHECK);
681 }
682
683 #if INCLUDE_CDS
684 // CDS support
685 objArrayOop prepare_resolved_references_for_archiving() NOT_CDS_JAVA_HEAP_RETURN_(nullptr);
686 void remove_unshareable_info();
687 void restore_unshareable_info(TRAPS);
688 private:
689 void remove_unshareable_entries();
690 void remove_resolved_klass_if_non_deterministic(int cp_index);
691 template <typename Function> void iterate_archivable_resolved_references(Function function);
692 #endif
693
694 private:
695 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
696 public:
697
698 // Get the tag for a constant, which may involve a constant dynamic
699 constantTag constant_tag_at(int cp_index);
700 // Get the basic type for a constant, which may involve a constant dynamic
701 BasicType basic_type_for_constant_at(int cp_index);
702
703 // Resolve late bound constants.
704 oop resolve_constant_at(int cp_index, TRAPS) {
705 constantPoolHandle h_this(THREAD, this);
706 return resolve_constant_at_impl(h_this, cp_index, _no_index_sentinel, nullptr, THREAD);
707 }
708
709 oop resolve_cached_constant_at(int cache_index, TRAPS) {
710 constantPoolHandle h_this(THREAD, this);
711 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, nullptr, THREAD);
712 }
713
714 oop resolve_possibly_cached_constant_at(int cp_index, TRAPS) {
715 constantPoolHandle h_this(THREAD, this);
716 return resolve_constant_at_impl(h_this, cp_index, _possible_index_sentinel, nullptr, THREAD);
717 }
718
719 oop find_cached_constant_at(int cp_index, bool& found_it, TRAPS) {
720 constantPoolHandle h_this(THREAD, this);
721 return resolve_constant_at_impl(h_this, cp_index, _possible_index_sentinel, &found_it, THREAD);
722 }
723
724 void copy_bootstrap_arguments_at(int cp_index,
725 int start_arg, int end_arg,
726 objArrayHandle info, int pos,
727 bool must_resolve, Handle if_not_available, TRAPS) {
728 constantPoolHandle h_this(THREAD, this);
729 copy_bootstrap_arguments_at_impl(h_this, cp_index, start_arg, end_arg,
730 info, pos, must_resolve, if_not_available, THREAD);
731 }
732
733 // Klass name matches name at offset
734 bool klass_name_at_matches(const InstanceKlass* k, int cp_index);
735
736 // Sizing
737 int length() const { return _length; }
738 void set_length(int length) { _length = length; }
739
740 // Tells whether index is within bounds.
741 bool is_within_bounds(int index) const {
742 return 0 <= index && index < length();
743 }
744
745 // Sizing (in words)
746 static int header_size() {
747 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize;
748 }
749 static int size(int length) { return align_metadata_size(header_size() + length); }
750 int size() const { return size(length()); }
751
752 // ConstantPools should be stored in the read-only region of CDS archive.
753 static bool is_read_only_by_default() { return true; }
754
755 friend class ClassFileParser;
756 friend class SystemDictionary;
757
758 // Used by CDS. These classes need to access the private ConstantPool() constructor.
759 template <class T> friend class CppVtableTesterA;
760 template <class T> friend class CppVtableTesterB;
761 template <class T> friend class CppVtableCloner;
762
763 // Used by compiler to prevent classloading.
764 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which);
765 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which, Bytecodes::Code code);
766 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which, Bytecodes::Code code);
767 static bool has_local_signature_at_if_loaded (const constantPoolHandle& this_cp, int which, Bytecodes::Code code);
768 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which);
769
770 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
771 // future by other Java code. These take constant pool indices rather than
772 // constant pool cache indices as do the peer methods above.
773 Symbol* uncached_klass_ref_at_noresolve(int cp_index);
774 Symbol* uncached_name_ref_at(int cp_index) {
775 int name_index = name_ref_index_at(uncached_name_and_type_ref_index_at(cp_index));
776 return symbol_at(name_index);
777 }
778 Symbol* uncached_signature_ref_at(int cp_index) {
779 int signature_index = signature_ref_index_at(uncached_name_and_type_ref_index_at(cp_index));
780 return symbol_at(signature_index);
781 }
782 u2 uncached_klass_ref_index_at(int cp_index);
783 u2 uncached_name_and_type_ref_index_at(int cp_index);
784
785 // Sharing
786 int pre_resolve_shared_klasses(TRAPS);
787
788 // Debugging
789 const char* printable_name_at(int cp_index) PRODUCT_RETURN_NULL;
790
791 private:
792
793 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); }
794 Array<u2>* reference_map() const { return (_cache == nullptr) ? nullptr : _cache->reference_map(); }
795 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); }
796
797 // Used while constructing constant pool (only by ClassFileParser)
798 jint klass_index_at(int cp_index) {
799 assert(tag_at(cp_index).is_klass_index(), "Corrupted constant pool");
800 return *int_at_addr(cp_index);
801 }
802
803 jint string_index_at(int cp_index) {
804 assert(tag_at(cp_index).is_string_index(), "Corrupted constant pool");
805 return *int_at_addr(cp_index);
806 }
807
808 // Performs the LinkResolver checks
809 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS);
810
811 // Implementation of methods that needs an exposed 'this' pointer, in order to
812 // handle GC while executing the method
813 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int cp_index, TRAPS);
814 static oop string_at_impl(const constantPoolHandle& this_cp, int cp_index, int obj_index, TRAPS);
815
816 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k);
817
818 // Resolve string constants (to prevent allocation during compilation)
819 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS);
820
821 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int cp_index, int cache_index,
822 bool* status_return, TRAPS);
823 static void copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int cp_index,
824 int start_arg, int end_arg,
825 objArrayHandle info, int pos,
826 bool must_resolve, Handle if_not_available, TRAPS);
827
828 // Exception handling
829 static void save_and_throw_exception(const constantPoolHandle& this_cp, int cp_index, constantTag tag, TRAPS);
830
831 public:
832 // Exception handling
833 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS);
834
835 // Merging ConstantPool* support:
836 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2);
837 void copy_cp_to(int start_cpi, int end_cpi, const constantPoolHandle& to_cp, int to_cpi, TRAPS) {
838 constantPoolHandle h_this(THREAD, this);
839 copy_cp_to_impl(h_this, start_cpi, end_cpi, to_cp, to_cpi, THREAD);
840 }
841 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_cpi, int end_cpi, const constantPoolHandle& to_cp, int to_cpi, TRAPS);
842 static void copy_entry_to(const constantPoolHandle& from_cp, int from_cpi, const constantPoolHandle& to_cp, int to_cpi);
843 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS);
844 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp);
845 int version() const { return _saved._version; }
846 void set_version(int version) { _saved._version = version; }
847 void increment_and_save_version(int version) {
848 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow
849 }
850
851 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
852 int resolved_reference_length() const { return _saved._resolved_reference_length; }
853
854 // Decrease ref counts of symbols that are in the constant pool
855 // when the holder class is unloaded
856 void unreference_symbols();
857
858 // Deallocate constant pool for RedefineClasses
859 void deallocate_contents(ClassLoaderData* loader_data);
860 void release_C_heap_structures();
861
862 // JVMTI access - GetConstantPool, RetransformClasses, ...
863 friend class JvmtiConstantPoolReconstituter;
864
865 private:
866 class SymbolHash: public CHeapObj<mtSymbol> {
867 ResourceHashtable<const Symbol*, u2, 256, AnyObj::C_HEAP, mtSymbol, Symbol::compute_hash> _table;
868
869 public:
870 void add_if_absent(const Symbol* sym, u2 value) {
871 bool created;
872 _table.put_if_absent(sym, value, &created);
873 }
874
875 u2 symbol_to_value(const Symbol* sym) {
876 u2* value = _table.get(sym);
877 return (value == nullptr) ? 0 : *value;
878 }
879 }; // End SymbolHash class
880
881 jint cpool_entry_size(jint idx);
882 jint hash_entries_to(SymbolHash *symmap, SymbolHash *classmap);
883
884 // Copy cpool bytes into byte array.
885 // Returns:
886 // int > 0, count of the raw cpool bytes that have been copied
887 // 0, OutOfMemory error
888 // -1, Internal error
889 int copy_cpool_bytes(int cpool_size,
890 SymbolHash* tbl,
891 unsigned char *bytes);
892
893 public:
894 // Verify
895 void verify_on(outputStream* st);
896
897 // Printing
898 void print_on(outputStream* st) const;
899 void print_value_on(outputStream* st) const;
900 void print_entry_on(int index, outputStream* st);
901
902 const char* internal_name() const { return "{constant pool}"; }
903
904 // ResolvedFieldEntry getters
905 inline ResolvedFieldEntry* resolved_field_entry_at(int field_index);
906 inline int resolved_field_entries_length() const;
907
908 // ResolvedMethodEntry getters
909 inline ResolvedMethodEntry* resolved_method_entry_at(int method_index);
910 inline int resolved_method_entries_length() const;
911 inline oop appendix_if_resolved(int method_index) const;
912
913 // ResolvedIndyEntry getters
914 inline ResolvedIndyEntry* resolved_indy_entry_at(int index);
915 inline int resolved_indy_entries_length() const;
916 inline oop resolved_reference_from_indy(int index) const;
917 inline oop resolved_reference_from_method(int index) const;
918 };
919
920 #endif // SHARE_OOPS_CONSTANTPOOL_HPP