1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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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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 ClassPrelinker; // CDS
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 };
114
115 u2 _flags; // old fashioned bit twiddling
116
117 int _length; // number of elements in the array
118
119 union {
120 // set for CDS to restore resolved references
121 int _resolved_reference_length;
122 // keeps version number for redefined classes (used in backtrace)
123 int _version;
124 } _saved;
125
126 void set_tags(Array<u1>* tags) { _tags = tags; }
127 void tag_at_put(int cp_index, jbyte t) { tags()->at_put(cp_index, t); }
128 void release_tag_at_put(int cp_index, jbyte t) { tags()->release_at_put(cp_index, t); }
129
130 u1* tag_addr_at(int cp_index) const { return tags()->adr_at(cp_index); }
131
132 void set_operands(Array<u2>* operands) { _operands = operands; }
133
134 u2 flags() const { return _flags; }
135 void set_flags(u2 f) { _flags = f; }
136
137 private:
138 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
139
140 intptr_t* obj_at_addr(int cp_index) const {
141 assert(is_within_bounds(cp_index), "index out of bounds");
142 return (intptr_t*) &base()[cp_index];
143 }
144
145 jint* int_at_addr(int cp_index) const {
146 assert(is_within_bounds(cp_index), "index out of bounds");
147 return (jint*) &base()[cp_index];
148 }
149
150 jlong* long_at_addr(int cp_index) const {
151 assert(is_within_bounds(cp_index), "index out of bounds");
152 return (jlong*) &base()[cp_index];
153 }
154
155 jfloat* float_at_addr(int cp_index) const {
156 assert(is_within_bounds(cp_index), "index out of bounds");
157 return (jfloat*) &base()[cp_index];
158 }
159
160 jdouble* double_at_addr(int cp_index) const {
161 assert(is_within_bounds(cp_index), "index out of bounds");
162 return (jdouble*) &base()[cp_index];
163 }
164
165 ConstantPool(Array<u1>* tags);
166 ConstantPool();
167 public:
168 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
169
170 virtual bool is_constantPool() const { return true; }
171
172 Array<u1>* tags() const { return _tags; }
173 Array<u2>* operands() const { return _operands; }
174
175 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; }
176 void set_has_preresolution() {
177 assert(!is_shared(), "should never be called on shared ConstantPools");
178 _flags |= _has_preresolution;
179 }
180
181 // minor and major version numbers of class file
182 u2 major_version() const { return _major_version; }
183 void set_major_version(u2 major_version) { _major_version = major_version; }
184 u2 minor_version() const { return _minor_version; }
185 void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
186
187 // generics support
188 Symbol* generic_signature() const {
189 return (_generic_signature_index == 0) ?
190 nullptr : symbol_at(_generic_signature_index);
191 }
192 u2 generic_signature_index() const { return _generic_signature_index; }
193 void set_generic_signature_index(u2 sig_index) { _generic_signature_index = sig_index; }
194
195 // source file name
196 Symbol* source_file_name() const {
197 return (_source_file_name_index == 0) ?
198 nullptr : symbol_at(_source_file_name_index);
199 }
200 u2 source_file_name_index() const { return _source_file_name_index; }
201 void set_source_file_name_index(u2 sourcefile_index) { _source_file_name_index = sourcefile_index; }
202
203 void copy_fields(const ConstantPool* orig);
204
205 // Redefine classes support. If a method referring to this constant pool
206 // is on the executing stack, or as a handle in vm code, this constant pool
207 // can't be removed from the set of previous versions saved in the instance
208 // class.
209 bool on_stack() const;
210 bool is_maybe_on_stack() const;
211 void set_on_stack(const bool value);
212
213 // Faster than MetaspaceObj::is_shared() - used by set_on_stack()
214 bool is_shared() const { return (_flags & _is_shared) != 0; }
215
216 bool has_dynamic_constant() const { return (_flags & _has_dynamic_constant) != 0; }
217 void set_has_dynamic_constant() { _flags |= _has_dynamic_constant; }
218
219 // Klass holding pool
220 InstanceKlass* pool_holder() const { return _pool_holder; }
221 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; }
222 InstanceKlass** pool_holder_addr() { return &_pool_holder; }
223
224 // Interpreter runtime support
225 ConstantPoolCache* cache() const { return _cache; }
226 void set_cache(ConstantPoolCache* cache){ _cache = cache; }
227
228 virtual void metaspace_pointers_do(MetaspaceClosure* iter);
229 virtual MetaspaceObj::Type type() const { return ConstantPoolType; }
230
231 // Create object cache in the constant pool
232 void initialize_resolved_references(ClassLoaderData* loader_data,
233 const intStack& reference_map,
234 int constant_pool_map_length,
235 TRAPS);
236
237 // resolved strings, methodHandles and callsite objects from the constant pool
238 objArrayOop resolved_references() const;
239 objArrayOop resolved_references_or_null() const;
240 oop resolved_reference_at(int obj_index) const;
241 oop set_resolved_reference_at(int index, oop new_value);
242
243 // mapping resolved object array indexes to cp indexes and back.
244 int object_to_cp_index(int index) { return reference_map()->at(index); }
245 int cp_to_object_index(int index);
246
247 void set_resolved_klasses(Array<Klass*>* rk) { _resolved_klasses = rk; }
248 Array<Klass*>* resolved_klasses() const { return _resolved_klasses; }
249 void allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS);
250 void initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS);
251
252 // Given the per-instruction index of an indy instruction, report the
253 // main constant pool entry for its bootstrap specifier.
254 // From there, uncached_name/signature_ref_at will get the name/type.
255 inline u2 invokedynamic_bootstrap_ref_index_at(int indy_index) const;
256
257 // Assembly code support
258 static ByteSize tags_offset() { return byte_offset_of(ConstantPool, _tags); }
259 static ByteSize cache_offset() { return byte_offset_of(ConstantPool, _cache); }
260 static ByteSize pool_holder_offset() { return byte_offset_of(ConstantPool, _pool_holder); }
261 static ByteSize resolved_klasses_offset() { return byte_offset_of(ConstantPool, _resolved_klasses); }
262
263 // Storing constants
264
265 // For temporary use while constructing constant pool
266 void klass_index_at_put(int cp_index, int name_index) {
267 tag_at_put(cp_index, JVM_CONSTANT_ClassIndex);
268 *int_at_addr(cp_index) = name_index;
269 }
270
271 // Hidden class support:
272 void klass_at_put(int class_index, Klass* k);
273
274 void unresolved_klass_at_put(int cp_index, int name_index, int resolved_klass_index) {
275 release_tag_at_put(cp_index, JVM_CONSTANT_UnresolvedClass);
276
277 assert((name_index & 0xffff0000) == 0, "must be");
278 assert((resolved_klass_index & 0xffff0000) == 0, "must be");
279 *int_at_addr(cp_index) =
280 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
281 }
282
283 void method_handle_index_at_put(int cp_index, int ref_kind, int ref_index) {
284 tag_at_put(cp_index, JVM_CONSTANT_MethodHandle);
285 *int_at_addr(cp_index) = ((jint) ref_index<<16) | ref_kind;
286 }
287
288 void method_type_index_at_put(int cp_index, int ref_index) {
289 tag_at_put(cp_index, JVM_CONSTANT_MethodType);
290 *int_at_addr(cp_index) = ref_index;
291 }
292
293 void dynamic_constant_at_put(int cp_index, int bsms_attribute_index, int name_and_type_index) {
294 tag_at_put(cp_index, JVM_CONSTANT_Dynamic);
295 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
296 }
297
298 void invoke_dynamic_at_put(int cp_index, int bsms_attribute_index, int name_and_type_index) {
299 tag_at_put(cp_index, JVM_CONSTANT_InvokeDynamic);
300 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
301 }
302
303 void unresolved_string_at_put(int cp_index, Symbol* s) {
304 assert(s->refcount() != 0, "should have nonzero refcount");
305 // Note that release_tag_at_put is not needed here because this is called only
306 // when constructing a ConstantPool in a single thread, with no possibility
307 // of concurrent access.
308 tag_at_put(cp_index, JVM_CONSTANT_String);
309 *symbol_at_addr(cp_index) = s;
310 }
311
312 void int_at_put(int cp_index, jint i) {
313 tag_at_put(cp_index, JVM_CONSTANT_Integer);
314 *int_at_addr(cp_index) = i;
315 }
316
317 void long_at_put(int cp_index, jlong l) {
318 tag_at_put(cp_index, JVM_CONSTANT_Long);
319 // *long_at_addr(which) = l;
320 Bytes::put_native_u8((address)long_at_addr(cp_index), *((u8*) &l));
321 }
322
323 void float_at_put(int cp_index, jfloat f) {
324 tag_at_put(cp_index, JVM_CONSTANT_Float);
325 *float_at_addr(cp_index) = f;
326 }
327
328 void double_at_put(int cp_index, jdouble d) {
329 tag_at_put(cp_index, JVM_CONSTANT_Double);
330 // *double_at_addr(which) = d;
331 // u8 temp = *(u8*) &d;
332 Bytes::put_native_u8((address) double_at_addr(cp_index), *((u8*) &d));
333 }
334
335 Symbol** symbol_at_addr(int cp_index) const {
336 assert(is_within_bounds(cp_index), "index out of bounds");
337 return (Symbol**) &base()[cp_index];
338 }
339
340 void symbol_at_put(int cp_index, Symbol* s) {
341 assert(s->refcount() != 0, "should have nonzero refcount");
342 tag_at_put(cp_index, JVM_CONSTANT_Utf8);
343 *symbol_at_addr(cp_index) = s;
344 }
345
346 void string_at_put(int obj_index, oop str);
347
348 // For temporary use while constructing constant pool
349 void string_index_at_put(int cp_index, int string_index) {
350 tag_at_put(cp_index, JVM_CONSTANT_StringIndex);
351 *int_at_addr(cp_index) = string_index;
352 }
353
354 void field_at_put(int cp_index, int class_index, int name_and_type_index) {
355 tag_at_put(cp_index, JVM_CONSTANT_Fieldref);
356 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index;
357 }
358
359 void method_at_put(int cp_index, int class_index, int name_and_type_index) {
360 tag_at_put(cp_index, JVM_CONSTANT_Methodref);
361 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index;
362 }
363
364 void interface_method_at_put(int cp_index, int class_index, int name_and_type_index) {
365 tag_at_put(cp_index, JVM_CONSTANT_InterfaceMethodref);
366 *int_at_addr(cp_index) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
367 }
368
369 void name_and_type_at_put(int cp_index, int name_index, int signature_index) {
370 tag_at_put(cp_index, JVM_CONSTANT_NameAndType);
371 *int_at_addr(cp_index) = ((jint) signature_index<<16) | name_index; // Not so nice
372 }
373
374 // Tag query
375
376 constantTag tag_at(int cp_index) const { return (constantTag)tags()->at_acquire(cp_index); }
377
378 // Fetching constants
379
380 Klass* klass_at(int cp_index, TRAPS) {
381 constantPoolHandle h_this(THREAD, this);
382 return klass_at_impl(h_this, cp_index, THREAD);
383 }
384
385 CPKlassSlot klass_slot_at(int cp_index) const {
386 assert(tag_at(cp_index).is_unresolved_klass() || tag_at(cp_index).is_klass(),
387 "Corrupted constant pool");
388 int value = *int_at_addr(cp_index);
389 int name_index = extract_high_short_from_int(value);
390 int resolved_klass_index = extract_low_short_from_int(value);
391 return CPKlassSlot(name_index, resolved_klass_index);
392 }
393
394 Symbol* klass_name_at(int cp_index) const; // Returns the name, w/o resolving.
395 int klass_name_index_at(int cp_index) const {
396 return klass_slot_at(cp_index).name_index();
397 }
398
399 Klass* resolved_klass_at(int cp_index) const; // Used by Compiler
400
401 // RedefineClasses() API support:
402 Symbol* klass_at_noresolve(int cp_index) { return klass_name_at(cp_index); }
403 void temp_unresolved_klass_at_put(int cp_index, int name_index) {
404 // Used only during constant pool merging for class redefinition. The resolved klass index
405 // will be initialized later by a call to initialize_unresolved_klasses().
406 unresolved_klass_at_put(cp_index, name_index, CPKlassSlot::_temp_resolved_klass_index);
407 }
408
409 jint int_at(int cp_index) const {
410 assert(tag_at(cp_index).is_int(), "Corrupted constant pool");
411 return *int_at_addr(cp_index);
412 }
413
414 jlong long_at(int cp_index) {
415 assert(tag_at(cp_index).is_long(), "Corrupted constant pool");
416 // return *long_at_addr(cp_index);
417 u8 tmp = Bytes::get_native_u8((address)&base()[cp_index]);
418 return *((jlong*)&tmp);
419 }
420
421 jfloat float_at(int cp_index) {
422 assert(tag_at(cp_index).is_float(), "Corrupted constant pool");
423 return *float_at_addr(cp_index);
424 }
425
426 jdouble double_at(int cp_index) {
427 assert(tag_at(cp_index).is_double(), "Corrupted constant pool");
428 u8 tmp = Bytes::get_native_u8((address)&base()[cp_index]);
429 return *((jdouble*)&tmp);
430 }
431
432 Symbol* symbol_at(int cp_index) const {
433 assert(tag_at(cp_index).is_utf8(), "Corrupted constant pool");
434 return *symbol_at_addr(cp_index);
435 }
436
437 oop string_at(int cp_index, int obj_index, TRAPS) {
438 constantPoolHandle h_this(THREAD, this);
439 return string_at_impl(h_this, cp_index, obj_index, THREAD);
440 }
441 oop string_at(int cp_index, TRAPS) {
442 int obj_index = cp_to_object_index(cp_index);
443 return string_at(cp_index, obj_index, THREAD);
444 }
445
446 // Version that can be used before string oop array is created.
447 oop uncached_string_at(int cp_index, TRAPS);
448
449 // only called when we are sure a string entry is already resolved (via an
450 // earlier string_at call.
451 oop resolved_string_at(int cp_index) {
452 assert(tag_at(cp_index).is_string(), "Corrupted constant pool");
453 // Must do an acquire here in case another thread resolved the klass
454 // behind our back, lest we later load stale values thru the oop.
455 // we might want a volatile_obj_at in ObjArrayKlass.
456 int obj_index = cp_to_object_index(cp_index);
457 return resolved_reference_at(obj_index);
458 }
459
460 Symbol* unresolved_string_at(int cp_index) {
461 assert(tag_at(cp_index).is_string(), "Corrupted constant pool");
462 return *symbol_at_addr(cp_index);
463 }
464
465 // Returns an UTF8 for a CONSTANT_String entry at a given index.
466 // UTF8 char* representation was chosen to avoid conversion of
467 // java_lang_Strings at resolved entries into Symbol*s
468 // or vice versa.
469 char* string_at_noresolve(int cp_index);
470
471 jint name_and_type_at(int cp_index) {
472 assert(tag_at(cp_index).is_name_and_type(), "Corrupted constant pool");
473 return *int_at_addr(cp_index);
474 }
475
476 int method_handle_ref_kind_at(int cp_index) {
477 assert(tag_at(cp_index).is_method_handle() ||
478 tag_at(cp_index).is_method_handle_in_error(), "Corrupted constant pool");
479 return extract_low_short_from_int(*int_at_addr(cp_index)); // mask out unwanted ref_index bits
480 }
481 int method_handle_index_at(int cp_index) {
482 assert(tag_at(cp_index).is_method_handle() ||
483 tag_at(cp_index).is_method_handle_in_error(), "Corrupted constant pool");
484 return extract_high_short_from_int(*int_at_addr(cp_index)); // shift out unwanted ref_kind bits
485 }
486 int method_type_index_at(int cp_index) {
487 assert(tag_at(cp_index).is_method_type() ||
488 tag_at(cp_index).is_method_type_in_error(), "Corrupted constant pool");
489 return *int_at_addr(cp_index);
490 }
491
492 // Derived queries:
493 Symbol* method_handle_name_ref_at(int cp_index) {
494 int member = method_handle_index_at(cp_index);
495 return uncached_name_ref_at(member);
496 }
497 Symbol* method_handle_signature_ref_at(int cp_index) {
498 int member = method_handle_index_at(cp_index);
499 return uncached_signature_ref_at(member);
500 }
501 u2 method_handle_klass_index_at(int cp_index) {
502 int member = method_handle_index_at(cp_index);
503 return uncached_klass_ref_index_at(member);
504 }
505 Symbol* method_type_signature_at(int cp_index) {
506 int sym = method_type_index_at(cp_index);
507 return symbol_at(sym);
508 }
509
510 u2 bootstrap_name_and_type_ref_index_at(int cp_index) {
511 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
512 return extract_high_short_from_int(*int_at_addr(cp_index));
513 }
514 u2 bootstrap_methods_attribute_index(int cp_index) {
515 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
516 return extract_low_short_from_int(*int_at_addr(cp_index));
517 }
518 int bootstrap_operand_base(int cp_index) {
519 int bsms_attribute_index = bootstrap_methods_attribute_index(cp_index);
520 return operand_offset_at(operands(), bsms_attribute_index);
521 }
522 // The first part of the operands array consists of an index into the second part.
523 // Extract a 32-bit index value from the first part.
524 static int operand_offset_at(Array<u2>* operands, int bsms_attribute_index) {
525 int n = (bsms_attribute_index * 2);
526 assert(n >= 0 && n+2 <= operands->length(), "oob");
527 // The first 32-bit index points to the beginning of the second part
528 // of the operands array. Make sure this index is in the first part.
529 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
530 operands->at(1)));
531 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
532 int offset = build_int_from_shorts(operands->at(n+0),
533 operands->at(n+1));
534 // The offset itself must point into the second part of the array.
535 assert(offset == 0 || (offset >= second_part && offset <= operands->length()), "oob (3)");
536 return offset;
537 }
538 static void operand_offset_at_put(Array<u2>* operands, int bsms_attribute_index, int offset) {
539 int n = bsms_attribute_index * 2;
540 assert(n >= 0 && n+2 <= operands->length(), "oob");
541 operands->at_put(n+0, extract_low_short_from_int(offset));
542 operands->at_put(n+1, extract_high_short_from_int(offset));
543 }
544 static int operand_array_length(Array<u2>* operands) {
545 if (operands == nullptr || operands->length() == 0) return 0;
546 int second_part = operand_offset_at(operands, 0);
547 return (second_part / 2);
548 }
549
550 #ifdef ASSERT
551 // operand tuples fit together exactly, end to end
552 static int operand_limit_at(Array<u2>* operands, int bsms_attribute_index) {
553 int nextidx = bsms_attribute_index + 1;
554 if (nextidx == operand_array_length(operands))
555 return operands->length();
556 else
557 return operand_offset_at(operands, nextidx);
558 }
559 int bootstrap_operand_limit(int cp_index) {
560 int bsms_attribute_index = bootstrap_methods_attribute_index(cp_index);
561 return operand_limit_at(operands(), bsms_attribute_index);
562 }
563 #endif //ASSERT
564
565 // Layout of InvokeDynamic and Dynamic bootstrap method specifier
566 // data in second part of operands array. This encodes one record in
567 // the BootstrapMethods attribute. The whole specifier also includes
568 // the name and type information from the main constant pool entry.
569 enum {
570 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
571 _indy_argc_offset = 1, // u2 argc
572 _indy_argv_offset = 2 // u2 argv[argc]
573 };
574
575 // These functions are used in RedefineClasses for CP merge
576
577 int operand_offset_at(int bsms_attribute_index) {
578 assert(0 <= bsms_attribute_index &&
579 bsms_attribute_index < operand_array_length(operands()),
580 "Corrupted CP operands");
581 return operand_offset_at(operands(), bsms_attribute_index);
582 }
583 u2 operand_bootstrap_method_ref_index_at(int bsms_attribute_index) {
584 int offset = operand_offset_at(bsms_attribute_index);
585 return operands()->at(offset + _indy_bsm_offset);
586 }
587 u2 operand_argument_count_at(int bsms_attribute_index) {
588 int offset = operand_offset_at(bsms_attribute_index);
589 u2 argc = operands()->at(offset + _indy_argc_offset);
590 return argc;
591 }
592 u2 operand_argument_index_at(int bsms_attribute_index, int j) {
593 int offset = operand_offset_at(bsms_attribute_index);
594 return operands()->at(offset + _indy_argv_offset + j);
595 }
596 int operand_next_offset_at(int bsms_attribute_index) {
597 int offset = operand_offset_at(bsms_attribute_index) + _indy_argv_offset
598 + operand_argument_count_at(bsms_attribute_index);
599 return offset;
600 }
601 // Compare a bootstrap specifier data in the operands arrays
602 bool compare_operand_to(int bsms_attribute_index1, const constantPoolHandle& cp2,
603 int bsms_attribute_index2);
604 // Find a bootstrap specifier data in the operands array
605 int find_matching_operand(int bsms_attribute_index, const constantPoolHandle& search_cp,
606 int operands_cur_len);
607 // Resize the operands array with delta_len and delta_size
608 void resize_operands(int delta_len, int delta_size, TRAPS);
609 // Extend the operands array with the length and size of the ext_cp operands
610 void extend_operands(const constantPoolHandle& ext_cp, TRAPS);
611 // Shrink the operands array to a smaller array with new_len length
612 void shrink_operands(int new_len, TRAPS);
613
614 u2 bootstrap_method_ref_index_at(int cp_index) {
615 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
616 int op_base = bootstrap_operand_base(cp_index);
617 return operands()->at(op_base + _indy_bsm_offset);
618 }
619 u2 bootstrap_argument_count_at(int cp_index) {
620 assert(tag_at(cp_index).has_bootstrap(), "Corrupted constant pool");
621 int op_base = bootstrap_operand_base(cp_index);
622 u2 argc = operands()->at(op_base + _indy_argc_offset);
623 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
624 int next_offset = bootstrap_operand_limit(cp_index));
625 assert(end_offset == next_offset, "matched ending");
626 return argc;
627 }
628 u2 bootstrap_argument_index_at(int cp_index, int j) {
629 int op_base = bootstrap_operand_base(cp_index);
630 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
631 assert((uint)j < (uint)argc, "oob");
632 return operands()->at(op_base + _indy_argv_offset + j);
633 }
634
635 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
636 // name_and_type_ref_index_at) all expect to be passed indices obtained
637 // directly from the bytecode.
638 // If the indices are meant to refer to fields or methods, they are
639 // actually rewritten indices that point to entries in their respective structures
640 // i.e. ResolvedMethodEntries or ResolvedFieldEntries.
641 // The routine to_cp_index manages the adjustment
642 // of these values back to constant pool indices.
643
644 // There are also "uncached" versions which do not adjust the operand index; see below.
645
646 // Lookup for entries consisting of (klass_index, name_and_type index)
647 Klass* klass_ref_at(int which, Bytecodes::Code code, TRAPS);
648 Symbol* klass_ref_at_noresolve(int which, Bytecodes::Code code);
649 Symbol* name_ref_at(int which, Bytecodes::Code code) {
650 int name_index = name_ref_index_at(name_and_type_ref_index_at(which, code));
651 return symbol_at(name_index);
652 }
653 Symbol* signature_ref_at(int which, Bytecodes::Code code) {
654 int signature_index = signature_ref_index_at(name_and_type_ref_index_at(which, code));
655 return symbol_at(signature_index);
656 }
657
658 u2 klass_ref_index_at(int which, Bytecodes::Code code);
659 u2 name_and_type_ref_index_at(int which, Bytecodes::Code code);
660
661 constantTag tag_ref_at(int cp_cache_index, Bytecodes::Code code);
662
663 int to_cp_index(int which, Bytecodes::Code code);
664
665 bool is_resolved(int which, Bytecodes::Code code);
666
667 // Lookup for entries consisting of (name_index, signature_index)
668 u2 name_ref_index_at(int cp_index); // == low-order jshort of name_and_type_at(cp_index)
669 u2 signature_ref_index_at(int cp_index); // == high-order jshort of name_and_type_at(cp_index)
670
671 BasicType basic_type_for_signature_at(int cp_index) const;
672
673 // Resolve string constants (to prevent allocation during compilation)
674 void resolve_string_constants(TRAPS) {
675 constantPoolHandle h_this(THREAD, this);
676 resolve_string_constants_impl(h_this, CHECK);
677 }
678
679 #if INCLUDE_CDS
680 // CDS support
681 objArrayOop prepare_resolved_references_for_archiving() NOT_CDS_JAVA_HEAP_RETURN_(nullptr);
682 void add_dumped_interned_strings() NOT_CDS_JAVA_HEAP_RETURN;
683 void remove_unshareable_info();
684 void restore_unshareable_info(TRAPS);
685 private:
686 void remove_unshareable_entries();
687 void remove_resolved_klass_if_non_deterministic(int cp_index);
688 #endif
689
690 private:
691 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
692 public:
693
694 // Get the tag for a constant, which may involve a constant dynamic
695 constantTag constant_tag_at(int cp_index);
696 // Get the basic type for a constant, which may involve a constant dynamic
697 BasicType basic_type_for_constant_at(int cp_index);
698
699 // Resolve late bound constants.
700 oop resolve_constant_at(int cp_index, TRAPS) {
701 constantPoolHandle h_this(THREAD, this);
702 return resolve_constant_at_impl(h_this, cp_index, _no_index_sentinel, nullptr, THREAD);
703 }
704
705 oop resolve_cached_constant_at(int cache_index, TRAPS) {
706 constantPoolHandle h_this(THREAD, this);
707 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, nullptr, THREAD);
708 }
709
710 oop resolve_possibly_cached_constant_at(int cp_index, TRAPS) {
711 constantPoolHandle h_this(THREAD, this);
712 return resolve_constant_at_impl(h_this, cp_index, _possible_index_sentinel, nullptr, THREAD);
713 }
714
715 oop find_cached_constant_at(int cp_index, bool& found_it, TRAPS) {
716 constantPoolHandle h_this(THREAD, this);
717 return resolve_constant_at_impl(h_this, cp_index, _possible_index_sentinel, &found_it, THREAD);
718 }
719
720 void copy_bootstrap_arguments_at(int cp_index,
721 int start_arg, int end_arg,
722 objArrayHandle info, int pos,
723 bool must_resolve, Handle if_not_available, TRAPS) {
724 constantPoolHandle h_this(THREAD, this);
725 copy_bootstrap_arguments_at_impl(h_this, cp_index, start_arg, end_arg,
726 info, pos, must_resolve, if_not_available, THREAD);
727 }
728
729 // Klass name matches name at offset
730 bool klass_name_at_matches(const InstanceKlass* k, int cp_index);
731
732 // Sizing
733 int length() const { return _length; }
734 void set_length(int length) { _length = length; }
735
736 // Tells whether index is within bounds.
737 bool is_within_bounds(int index) const {
738 return 0 <= index && index < length();
739 }
740
741 // Sizing (in words)
742 static int header_size() {
743 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize;
744 }
745 static int size(int length) { return align_metadata_size(header_size() + length); }
746 int size() const { return size(length()); }
747
748 // ConstantPools should be stored in the read-only region of CDS archive.
749 static bool is_read_only_by_default() { return true; }
750
751 friend class ClassFileParser;
752 friend class SystemDictionary;
753
754 // Used by CDS. These classes need to access the private ConstantPool() constructor.
755 template <class T> friend class CppVtableTesterA;
756 template <class T> friend class CppVtableTesterB;
757 template <class T> friend class CppVtableCloner;
758
759 // Used by compiler to prevent classloading.
760 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which);
761 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which, Bytecodes::Code code);
762 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which, Bytecodes::Code code);
763 static bool has_local_signature_at_if_loaded (const constantPoolHandle& this_cp, int which, Bytecodes::Code code);
764 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which);
765
766 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
767 // future by other Java code. These take constant pool indices rather than
768 // constant pool cache indices as do the peer methods above.
769 Symbol* uncached_klass_ref_at_noresolve(int cp_index);
770 Symbol* uncached_name_ref_at(int cp_index) {
771 int name_index = name_ref_index_at(uncached_name_and_type_ref_index_at(cp_index));
772 return symbol_at(name_index);
773 }
774 Symbol* uncached_signature_ref_at(int cp_index) {
775 int signature_index = signature_ref_index_at(uncached_name_and_type_ref_index_at(cp_index));
776 return symbol_at(signature_index);
777 }
778 u2 uncached_klass_ref_index_at(int cp_index);
779 u2 uncached_name_and_type_ref_index_at(int cp_index);
780
781 // Sharing
782 int pre_resolve_shared_klasses(TRAPS);
783
784 // Debugging
785 const char* printable_name_at(int cp_index) PRODUCT_RETURN_NULL;
786
787 private:
788
789 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); }
790 Array<u2>* reference_map() const { return (_cache == nullptr) ? nullptr : _cache->reference_map(); }
791 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); }
792
793 // Used while constructing constant pool (only by ClassFileParser)
794 jint klass_index_at(int cp_index) {
795 assert(tag_at(cp_index).is_klass_index(), "Corrupted constant pool");
796 return *int_at_addr(cp_index);
797 }
798
799 jint string_index_at(int cp_index) {
800 assert(tag_at(cp_index).is_string_index(), "Corrupted constant pool");
801 return *int_at_addr(cp_index);
802 }
803
804 // Performs the LinkResolver checks
805 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS);
806
807 // Implementation of methods that needs an exposed 'this' pointer, in order to
808 // handle GC while executing the method
809 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int cp_index, TRAPS);
810 static oop string_at_impl(const constantPoolHandle& this_cp, int cp_index, int obj_index, TRAPS);
811
812 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k);
813
814 // Resolve string constants (to prevent allocation during compilation)
815 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS);
816
817 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int cp_index, int cache_index,
818 bool* status_return, TRAPS);
819 static void copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int cp_index,
820 int start_arg, int end_arg,
821 objArrayHandle info, int pos,
822 bool must_resolve, Handle if_not_available, TRAPS);
823
824 // Exception handling
825 static void save_and_throw_exception(const constantPoolHandle& this_cp, int cp_index, constantTag tag, TRAPS);
826
827 public:
828 // Exception handling
829 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS);
830
831 // Merging ConstantPool* support:
832 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2);
833 void copy_cp_to(int start_cpi, int end_cpi, const constantPoolHandle& to_cp, int to_cpi, TRAPS) {
834 constantPoolHandle h_this(THREAD, this);
835 copy_cp_to_impl(h_this, start_cpi, end_cpi, to_cp, to_cpi, THREAD);
836 }
837 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_cpi, int end_cpi, const constantPoolHandle& to_cp, int to_cpi, TRAPS);
838 static void copy_entry_to(const constantPoolHandle& from_cp, int from_cpi, const constantPoolHandle& to_cp, int to_cpi);
839 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS);
840 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp);
841 int version() const { return _saved._version; }
842 void set_version(int version) { _saved._version = version; }
843 void increment_and_save_version(int version) {
844 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow
845 }
846
847 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
848 int resolved_reference_length() const { return _saved._resolved_reference_length; }
849
850 // Decrease ref counts of symbols that are in the constant pool
851 // when the holder class is unloaded
852 void unreference_symbols();
853
854 // Deallocate constant pool for RedefineClasses
855 void deallocate_contents(ClassLoaderData* loader_data);
856 void release_C_heap_structures();
857
858 // JVMTI access - GetConstantPool, RetransformClasses, ...
859 friend class JvmtiConstantPoolReconstituter;
860
861 private:
862 class SymbolHash: public CHeapObj<mtSymbol> {
863 ResourceHashtable<const Symbol*, u2, 256, AnyObj::C_HEAP, mtSymbol, Symbol::compute_hash> _table;
864
865 public:
866 void add_if_absent(const Symbol* sym, u2 value) {
867 bool created;
868 _table.put_if_absent(sym, value, &created);
869 }
870
871 u2 symbol_to_value(const Symbol* sym) {
872 u2* value = _table.get(sym);
873 return (value == nullptr) ? 0 : *value;
874 }
875 }; // End SymbolHash class
876
877 jint cpool_entry_size(jint idx);
878 jint hash_entries_to(SymbolHash *symmap, SymbolHash *classmap);
879
880 // Copy cpool bytes into byte array.
881 // Returns:
882 // int > 0, count of the raw cpool bytes that have been copied
883 // 0, OutOfMemory error
884 // -1, Internal error
885 int copy_cpool_bytes(int cpool_size,
886 SymbolHash* tbl,
887 unsigned char *bytes);
888
889 public:
890 // Verify
891 void verify_on(outputStream* st);
892
893 // Printing
894 void print_on(outputStream* st) const;
895 void print_value_on(outputStream* st) const;
896 void print_entry_on(int index, outputStream* st);
897
898 const char* internal_name() const { return "{constant pool}"; }
899
900 // ResolvedFieldEntry getters
901 inline ResolvedFieldEntry* resolved_field_entry_at(int field_index);
902 inline int resolved_field_entries_length() const;
903
904 // ResolvedMethodEntry getters
905 inline ResolvedMethodEntry* resolved_method_entry_at(int method_index);
906 inline int resolved_method_entries_length() const;
907 inline oop appendix_if_resolved(int method_index) const;
908
909 // ResolvedIndyEntry getters
910 inline ResolvedIndyEntry* resolved_indy_entry_at(int index);
911 inline int resolved_indy_entries_length() const;
912 inline oop resolved_reference_from_indy(int index) const;
913 inline oop resolved_reference_from_method(int index) const;
914 };
915
916 #endif // SHARE_OOPS_CONSTANTPOOL_HPP