1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
24
25 #ifndef SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP
26 #define SHARE_VM_OOPS_CONSTANTPOOLOOP_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);
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
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_klass_at_put(int which, int name_index, int resolved_klass_index) {
285 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
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 method_handle_index_at_put(int which, int ref_kind, int ref_index) {
294 tag_at_put(which, JVM_CONSTANT_MethodHandle);
295 *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
296 }
297
298 void method_type_index_at_put(int which, int ref_index) {
299 tag_at_put(which, JVM_CONSTANT_MethodType);
300 *int_at_addr(which) = ref_index;
301 }
302
303 void dynamic_constant_at_put(int which, int bsms_attribute_index, int name_and_type_index) {
304 tag_at_put(which, JVM_CONSTANT_Dynamic);
305 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
306 }
307
308 void invoke_dynamic_at_put(int which, int bsms_attribute_index, int name_and_type_index) {
309 tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
310 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bsms_attribute_index;
311 }
312
313 void unresolved_string_at_put(int which, Symbol* s) {
314 release_tag_at_put(which, JVM_CONSTANT_String);
315 slot_at_put(which, CPSlot(s));
316 }
317
318 void int_at_put(int which, jint i) {
319 tag_at_put(which, JVM_CONSTANT_Integer);
320 *int_at_addr(which) = i;
321 }
322
323 void long_at_put(int which, jlong l) {
324 tag_at_put(which, JVM_CONSTANT_Long);
325 // *long_at_addr(which) = l;
326 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
327 }
328
329 void float_at_put(int which, jfloat f) {
330 tag_at_put(which, JVM_CONSTANT_Float);
331 *float_at_addr(which) = f;
332 }
333
334 void double_at_put(int which, jdouble d) {
335 tag_at_put(which, JVM_CONSTANT_Double);
336 // *double_at_addr(which) = d;
337 // u8 temp = *(u8*) &d;
338 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
339 }
340
341 Symbol** symbol_at_addr(int which) const {
342 assert(is_within_bounds(which), "index out of bounds");
343 return (Symbol**) &base()[which];
344 }
345
346 void symbol_at_put(int which, Symbol* s) {
347 assert(s->refcount() != 0, "should have nonzero refcount");
348 tag_at_put(which, JVM_CONSTANT_Utf8);
349 *symbol_at_addr(which) = s;
350 }
351
352 void string_at_put(int which, int obj_index, oop str);
353
354 // For temporary use while constructing constant pool
355 void string_index_at_put(int which, int string_index) {
356 tag_at_put(which, JVM_CONSTANT_StringIndex);
357 *int_at_addr(which) = string_index;
358 }
359
360 void field_at_put(int which, int class_index, int name_and_type_index) {
361 tag_at_put(which, JVM_CONSTANT_Fieldref);
362 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
363 }
364
365 void method_at_put(int which, int class_index, int name_and_type_index) {
366 tag_at_put(which, JVM_CONSTANT_Methodref);
367 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
368 }
369
370 void interface_method_at_put(int which, int class_index, int name_and_type_index) {
371 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
372 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
373 }
374
375 void name_and_type_at_put(int which, int name_index, int signature_index) {
376 tag_at_put(which, JVM_CONSTANT_NameAndType);
377 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice
378 }
379
380 // Tag query
381
382 constantTag tag_at(int which) const;
383
384 // Fetching constants
385
386 Klass* klass_at(int which, TRAPS) {
387 constantPoolHandle h_this(THREAD, this);
388 return klass_at_impl(h_this, which, true, THREAD);
389 }
390
391 // Version of klass_at that doesn't save the resolution error, called during deopt
392 Klass* klass_at_ignore_error(int which, TRAPS) {
393 constantPoolHandle h_this(THREAD, this);
394 return klass_at_impl(h_this, which, false, THREAD);
395 }
396
397 CPKlassSlot klass_slot_at(int which) const {
398 assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),
399 "Corrupted constant pool");
400 int value = *int_at_addr(which);
401 int name_index = extract_high_short_from_int(value);
402 int resolved_klass_index = extract_low_short_from_int(value);
403 return CPKlassSlot(name_index, resolved_klass_index);
404 }
405
406 Symbol* klass_name_at(int which) const; // Returns the name, w/o resolving.
407 int klass_name_index_at(int which) const {
408 return klass_slot_at(which).name_index();
409 }
410
411 Klass* resolved_klass_at(int which) const; // Used by Compiler
412
413 // RedefineClasses() API support:
414 Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
415 void temp_unresolved_klass_at_put(int which, int name_index) {
416 // Used only during constant pool merging for class redefinition. The resolved klass index
417 // will be initialized later by a call to initialize_unresolved_klasses().
418 unresolved_klass_at_put(which, name_index, CPKlassSlot::_temp_resolved_klass_index);
419 }
420
421 jint int_at(int which) {
422 assert(tag_at(which).is_int(), "Corrupted constant pool");
423 return *int_at_addr(which);
424 }
425
426 jlong long_at(int which) {
427 assert(tag_at(which).is_long(), "Corrupted constant pool");
428 // return *long_at_addr(which);
429 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
430 return *((jlong*)&tmp);
431 }
432
433 jfloat float_at(int which) {
434 assert(tag_at(which).is_float(), "Corrupted constant pool");
435 return *float_at_addr(which);
436 }
437
438 jdouble double_at(int which) {
439 assert(tag_at(which).is_double(), "Corrupted constant pool");
440 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
441 return *((jdouble*)&tmp);
442 }
443
444 Symbol* symbol_at(int which) const {
445 assert(tag_at(which).is_utf8(), "Corrupted constant pool");
446 return *symbol_at_addr(which);
447 }
448
449 oop string_at(int which, int obj_index, TRAPS) {
450 constantPoolHandle h_this(THREAD, this);
451 return string_at_impl(h_this, which, obj_index, THREAD);
452 }
453 oop string_at(int which, TRAPS) {
454 int obj_index = cp_to_object_index(which);
455 return string_at(which, obj_index, THREAD);
456 }
457
458 // Version that can be used before string oop array is created.
459 oop uncached_string_at(int which, TRAPS);
460
461 // A "pseudo-string" is an non-string oop that has found its way into
462 // a String entry.
463 // This can happen if the user patches a live
464 // object into a CONSTANT_String entry of an unsafe anonymous class.
465 // Method oops internally created for method handles may also
466 // use pseudo-strings to link themselves to related metaobjects.
467
468 bool is_pseudo_string_at(int which);
469
470 oop pseudo_string_at(int which, int obj_index);
471
472 oop pseudo_string_at(int which);
473
474 void pseudo_string_at_put(int which, int obj_index, oop x) {
475 assert(tag_at(which).is_string(), "Corrupted constant pool");
476 Symbol* sym = unresolved_string_at(which);
477 slot_at_put(which, CPSlot(sym, CPSlot::_pseudo_bit));
478 string_at_put(which, obj_index, x); // this works just fine
479 }
480
481 // only called when we are sure a string entry is already resolved (via an
482 // earlier string_at call.
483 oop resolved_string_at(int which) {
484 assert(tag_at(which).is_string(), "Corrupted constant pool");
485 // Must do an acquire here in case another thread resolved the klass
486 // behind our back, lest we later load stale values thru the oop.
487 // we might want a volatile_obj_at in ObjArrayKlass.
488 int obj_index = cp_to_object_index(which);
489 return resolved_references()->obj_at(obj_index);
490 }
491
492 Symbol* unresolved_string_at(int which) {
493 assert(tag_at(which).is_string(), "Corrupted constant pool");
494 Symbol* sym = slot_at(which).get_symbol();
495 return sym;
496 }
497
498 // Returns an UTF8 for a CONSTANT_String entry at a given index.
499 // UTF8 char* representation was chosen to avoid conversion of
500 // java_lang_Strings at resolved entries into Symbol*s
501 // or vice versa.
502 char* string_at_noresolve(int which);
503
504 jint name_and_type_at(int which) {
505 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
506 return *int_at_addr(which);
507 }
508
509 int method_handle_ref_kind_at(int which) {
510 assert(tag_at(which).is_method_handle() ||
511 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
512 return extract_low_short_from_int(*int_at_addr(which)); // mask out unwanted ref_index bits
513 }
514 int method_handle_index_at(int which) {
515 assert(tag_at(which).is_method_handle() ||
516 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool");
517 return extract_high_short_from_int(*int_at_addr(which)); // shift out unwanted ref_kind bits
518 }
519 int method_type_index_at(int which) {
520 assert(tag_at(which).is_method_type() ||
521 tag_at(which).is_method_type_in_error(), "Corrupted constant pool");
522 return *int_at_addr(which);
523 }
524
525 // Derived queries:
526 Symbol* method_handle_name_ref_at(int which) {
527 int member = method_handle_index_at(which);
528 return impl_name_ref_at(member, true);
529 }
530 Symbol* method_handle_signature_ref_at(int which) {
531 int member = method_handle_index_at(which);
532 return impl_signature_ref_at(member, true);
533 }
534 int method_handle_klass_index_at(int which) {
535 int member = method_handle_index_at(which);
536 return impl_klass_ref_index_at(member, true);
537 }
538 Symbol* method_type_signature_at(int which) {
539 int sym = method_type_index_at(which);
540 return symbol_at(sym);
541 }
542
543 int bootstrap_name_and_type_ref_index_at(int which) {
544 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
545 return extract_high_short_from_int(*int_at_addr(which));
546 }
547 int bootstrap_methods_attribute_index(int which) {
548 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
549 return extract_low_short_from_int(*int_at_addr(which));
550 }
551 int bootstrap_operand_base(int which) {
552 int bsms_attribute_index = bootstrap_methods_attribute_index(which);
553 return operand_offset_at(operands(), bsms_attribute_index);
554 }
555 // The first part of the operands array consists of an index into the second part.
556 // Extract a 32-bit index value from the first part.
557 static int operand_offset_at(Array<u2>* operands, int bsms_attribute_index) {
558 int n = (bsms_attribute_index * 2);
559 assert(n >= 0 && n+2 <= operands->length(), "oob");
560 // The first 32-bit index points to the beginning of the second part
561 // of the operands array. Make sure this index is in the first part.
562 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
563 operands->at(1)));
564 assert(second_part == 0 || n+2 <= second_part, "oob (2)");
565 int offset = build_int_from_shorts(operands->at(n+0),
566 operands->at(n+1));
567 // The offset itself must point into the second part of the array.
568 assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
569 return offset;
570 }
571 static void operand_offset_at_put(Array<u2>* operands, int bsms_attribute_index, int offset) {
572 int n = bsms_attribute_index * 2;
573 assert(n >= 0 && n+2 <= operands->length(), "oob");
574 operands->at_put(n+0, extract_low_short_from_int(offset));
575 operands->at_put(n+1, extract_high_short_from_int(offset));
576 }
577 static int operand_array_length(Array<u2>* operands) {
578 if (operands == NULL || operands->length() == 0) return 0;
579 int second_part = operand_offset_at(operands, 0);
580 return (second_part / 2);
581 }
582
583 #ifdef ASSERT
584 // operand tuples fit together exactly, end to end
585 static int operand_limit_at(Array<u2>* operands, int bsms_attribute_index) {
586 int nextidx = bsms_attribute_index + 1;
587 if (nextidx == operand_array_length(operands))
588 return operands->length();
589 else
590 return operand_offset_at(operands, nextidx);
591 }
592 int bootstrap_operand_limit(int which) {
593 int bsms_attribute_index = bootstrap_methods_attribute_index(which);
594 return operand_limit_at(operands(), bsms_attribute_index);
595 }
596 #endif //ASSERT
597
598 // Layout of InvokeDynamic and Dynamic bootstrap method specifier
599 // data in second part of operands array. This encodes one record in
600 // the BootstrapMethods attribute. The whole specifier also includes
601 // the name and type information from the main constant pool entry.
602 enum {
603 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm
604 _indy_argc_offset = 1, // u2 argc
605 _indy_argv_offset = 2 // u2 argv[argc]
606 };
607
608 // These functions are used in RedefineClasses for CP merge
609
610 int operand_offset_at(int bsms_attribute_index) {
611 assert(0 <= bsms_attribute_index &&
612 bsms_attribute_index < operand_array_length(operands()),
613 "Corrupted CP operands");
614 return operand_offset_at(operands(), bsms_attribute_index);
615 }
616 int operand_bootstrap_method_ref_index_at(int bsms_attribute_index) {
617 int offset = operand_offset_at(bsms_attribute_index);
618 return operands()->at(offset + _indy_bsm_offset);
619 }
620 int operand_argument_count_at(int bsms_attribute_index) {
621 int offset = operand_offset_at(bsms_attribute_index);
622 int argc = operands()->at(offset + _indy_argc_offset);
623 return argc;
624 }
625 int operand_argument_index_at(int bsms_attribute_index, int j) {
626 int offset = operand_offset_at(bsms_attribute_index);
627 return operands()->at(offset + _indy_argv_offset + j);
628 }
629 int operand_next_offset_at(int bsms_attribute_index) {
630 int offset = operand_offset_at(bsms_attribute_index) + _indy_argv_offset
631 + operand_argument_count_at(bsms_attribute_index);
632 return offset;
633 }
634 // Compare a bootstrap specifier data in the operands arrays
635 bool compare_operand_to(int bsms_attribute_index1, const constantPoolHandle& cp2,
636 int bsms_attribute_index2, TRAPS);
637 // Find a bootstrap specifier data in the operands array
638 int find_matching_operand(int bsms_attribute_index, const constantPoolHandle& search_cp,
639 int operands_cur_len, TRAPS);
640 // Resize the operands array with delta_len and delta_size
641 void resize_operands(int delta_len, int delta_size, TRAPS);
642 // Extend the operands array with the length and size of the ext_cp operands
643 void extend_operands(const constantPoolHandle& ext_cp, TRAPS);
644 // Shrink the operands array to a smaller array with new_len length
645 void shrink_operands(int new_len, TRAPS);
646
647 int bootstrap_method_ref_index_at(int which) {
648 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
649 int op_base = bootstrap_operand_base(which);
650 return operands()->at(op_base + _indy_bsm_offset);
651 }
652 int bootstrap_argument_count_at(int which) {
653 assert(tag_at(which).has_bootstrap(), "Corrupted constant pool");
654 int op_base = bootstrap_operand_base(which);
655 int argc = operands()->at(op_base + _indy_argc_offset);
656 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
657 int next_offset = bootstrap_operand_limit(which));
658 assert(end_offset == next_offset, "matched ending");
659 return argc;
660 }
661 int bootstrap_argument_index_at(int which, int j) {
662 int op_base = bootstrap_operand_base(which);
663 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
664 assert((uint)j < (uint)argc, "oob");
665 return operands()->at(op_base + _indy_argv_offset + j);
666 }
667
668 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
669 // name_and_type_ref_index_at) all expect to be passed indices obtained
670 // directly from the bytecode.
671 // If the indices are meant to refer to fields or methods, they are
672 // actually rewritten constant pool cache indices.
673 // The routine remap_instruction_operand_from_cache manages the adjustment
674 // of these values back to constant pool indices.
675
676 // There are also "uncached" versions which do not adjust the operand index; see below.
677
678 // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear.
679 // In a few cases (the verifier) there are uses before a cpcache has been built,
680 // which are handled by a dynamic check in remap_instruction_operand_from_cache.
681 // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode.
682
683 // Lookup for entries consisting of (klass_index, name_and_type index)
684 Klass* klass_ref_at(int which, TRAPS);
685 Symbol* klass_ref_at_noresolve(int which);
686 Symbol* name_ref_at(int which) { return impl_name_ref_at(which, false); }
687 Symbol* signature_ref_at(int which) { return impl_signature_ref_at(which, false); }
688
689 int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); }
690 int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); }
691
692 int remap_instruction_operand_from_cache(int operand); // operand must be biased by CPCACHE_INDEX_TAG
693
694 constantTag tag_ref_at(int cp_cache_index) { return impl_tag_ref_at(cp_cache_index, false); }
695
696 // Lookup for entries consisting of (name_index, signature_index)
697 int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt)
698 int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt)
699
700 BasicType basic_type_for_signature_at(int which) const;
701
702 // Resolve string constants (to prevent allocation during compilation)
703 void resolve_string_constants(TRAPS) {
704 constantPoolHandle h_this(THREAD, this);
705 resolve_string_constants_impl(h_this, CHECK);
706 }
707
708 // CDS support
709 void archive_resolved_references(Thread *THREAD) NOT_CDS_JAVA_HEAP_RETURN;
710 void resolve_class_constants(TRAPS) NOT_CDS_JAVA_HEAP_RETURN;
711 void remove_unshareable_info();
712 void restore_unshareable_info(TRAPS);
713 // The ConstantPool vtable is restored by this call when the ConstantPool is
714 // in the shared archive. See patch_klass_vtables() in metaspaceShared.cpp for
715 // all the gory details. SA, dtrace and pstack helpers distinguish metadata
716 // by their vtable.
717 void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); }
718
719 private:
720 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
721 public:
722
723 // Get the tag for a constant, which may involve a constant dynamic
724 constantTag constant_tag_at(int which);
725 // Get the basic type for a constant, which may involve a constant dynamic
726 BasicType basic_type_for_constant_at(int which);
727
728 // Resolve late bound constants.
729 oop resolve_constant_at(int index, TRAPS) {
730 constantPoolHandle h_this(THREAD, this);
731 return resolve_constant_at_impl(h_this, index, _no_index_sentinel, NULL, THREAD);
732 }
733
734 oop resolve_cached_constant_at(int cache_index, TRAPS) {
735 constantPoolHandle h_this(THREAD, this);
736 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, NULL, THREAD);
737 }
738
739 oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
740 constantPoolHandle h_this(THREAD, this);
741 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, NULL, THREAD);
742 }
743
744 oop find_cached_constant_at(int pool_index, bool& found_it, TRAPS) {
745 constantPoolHandle h_this(THREAD, this);
746 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, &found_it, THREAD);
747 }
748
749 enum BootstrapArgumentReferenceMode { R_IFPRESENT = 0, R_FORCE = 1, R_SYMREF = 2 };
750
751 void copy_bootstrap_arguments_at(int index,
752 int start_arg, int end_arg,
753 arrayHandle buf, int pos,
754 BootstrapArgumentReferenceMode resolving,
755 Handle if_not_available, Handle if_null_constant,
756 bool skip_non_null, // don't overwrite previous stuff in buf
757 bool skip_recursion, // don't resolve CONSTANT_Dynamic args
758 TRAPS) {
759 constantPoolHandle h_this(THREAD, this);
760 copy_bootstrap_arguments_at_impl(h_this, index, start_arg, end_arg,
761 buf, pos,
762 resolving, if_not_available, if_null_constant,
763 skip_non_null, skip_recursion, THREAD);
764 }
765
766 // Klass name matches name at offset
767 bool klass_name_at_matches(const InstanceKlass* k, int which);
768
769 // Sizing
770 int length() const { return _length; }
771 void set_length(int length) { _length = length; }
772
773 // Tells whether index is within bounds.
774 bool is_within_bounds(int index) const {
775 return 0 <= index && index < length();
776 }
777
778 // Sizing (in words)
779 static int header_size() {
780 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize;
781 }
782 static int size(int length) { return align_metadata_size(header_size() + length); }
783 int size() const { return size(length()); }
784 #if INCLUDE_SERVICES
785 void collect_statistics(KlassSizeStats *sz) const;
786 #endif
787
788 // ConstantPools should be stored in the read-only region of CDS archive.
789 static bool is_read_only_by_default() { return true; }
790
791 friend class ClassFileParser;
792 friend class SystemDictionary;
793
794 // Used by CDS. These classes need to access the private ConstantPool() constructor.
795 template <class T> friend class CppVtableTesterA;
796 template <class T> friend class CppVtableTesterB;
797 template <class T> friend class CppVtableCloner;
798
799 // Used by compiler to prevent classloading.
800 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which);
801 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
802 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which);
803 static bool has_local_signature_at_if_loaded (const constantPoolHandle& this_cp, int which);
804 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which);
805
806 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
807 // future by other Java code. These take constant pool indices rather than
808 // constant pool cache indices as do the peer methods above.
809 Symbol* uncached_klass_ref_at_noresolve(int which);
810 Symbol* uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); }
811 Symbol* uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); }
812 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); }
813 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); }
814
815 // Sharing
816 int pre_resolve_shared_klasses(TRAPS);
817
818 // Debugging
819 const char* printable_name_at(int which) PRODUCT_RETURN0;
820
821 #ifdef ASSERT
822 enum { CPCACHE_INDEX_TAG = 0x10000 }; // helps keep CP cache indices distinct from CP indices
823 #else
824 enum { CPCACHE_INDEX_TAG = 0 }; // in product mode, this zero value is a no-op
825 #endif //ASSERT
826
827 static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) {
828 if (invokedynamic_ok && is_invokedynamic_index(raw_index))
829 return decode_invokedynamic_index(raw_index);
830 else
831 return raw_index - CPCACHE_INDEX_TAG;
832 }
833
834 private:
835
836 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); }
837 Array<u2>* reference_map() const { return (_cache == NULL) ? NULL : _cache->reference_map(); }
838 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); }
839
840 // patch JSR 292 resolved references after the class is linked.
841 void patch_resolved_references(GrowableArray<Handle>* cp_patches);
842
843 Symbol* impl_name_ref_at(int which, bool uncached);
844 Symbol* impl_signature_ref_at(int which, bool uncached);
845
846 int impl_klass_ref_index_at(int which, bool uncached);
847 int impl_name_and_type_ref_index_at(int which, bool uncached);
848 constantTag impl_tag_ref_at(int which, bool uncached);
849
850 // Used while constructing constant pool (only by ClassFileParser)
851 jint klass_index_at(int which) {
852 assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
853 return *int_at_addr(which);
854 }
855
856 jint string_index_at(int which) {
857 assert(tag_at(which).is_string_index(), "Corrupted constant pool");
858 return *int_at_addr(which);
859 }
860
861 // Performs the LinkResolver checks
862 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS);
863
864 // Implementation of methods that needs an exposed 'this' pointer, in order to
865 // handle GC while executing the method
866 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int which,
867 bool save_resolution_error, TRAPS);
868 static oop string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS);
869
870 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k);
871
872 // Resolve string constants (to prevent allocation during compilation)
873 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS);
874
875 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int index, int cache_index,
876 bool* status_return, TRAPS);
877 static void copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int index,
878 int start_arg, int end_arg,
879 arrayHandle buf, int pos,
880 BootstrapArgumentReferenceMode resolving,
881 Handle if_not_available,
882 Handle if_null_constant,
883 bool skip_non_null,
884 bool skip_recursion,
885 TRAPS);
886
887 // Exception handling
888 static Symbol* exception_message(const constantPoolHandle& this_cp, int which, constantTag tag, oop pending_exception);
889 static void save_and_throw_exception(const constantPoolHandle& this_cp, int which, constantTag tag, TRAPS);
890
891 public:
892 // Exception handling
893 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS);
894
895 // Merging ConstantPool* support:
896 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2, TRAPS);
897 void copy_cp_to(int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS) {
898 constantPoolHandle h_this(THREAD, this);
899 copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
900 }
901 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
902 static void copy_entry_to(const constantPoolHandle& from_cp, int from_i, const constantPoolHandle& to_cp, int to_i, TRAPS);
903 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS);
904 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp, TRAPS);
905 int version() const { return _saved._version; }
906 void set_version(int version) { _saved._version = version; }
907 void increment_and_save_version(int version) {
908 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow
909 }
910
911 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
912 int resolved_reference_length() const { return _saved._resolved_reference_length; }
913
914 // Decrease ref counts of symbols that are in the constant pool
915 // when the holder class is unloaded
916 void unreference_symbols();
917
918 // Deallocate constant pool for RedefineClasses
919 void deallocate_contents(ClassLoaderData* loader_data);
920 void release_C_heap_structures();
921
922 // JVMTI accesss - GetConstantPool, RetransformClasses, ...
923 friend class JvmtiConstantPoolReconstituter;
924
925 private:
926 jint cpool_entry_size(jint idx);
927 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
928
929 // Copy cpool bytes into byte array.
930 // Returns:
931 // int > 0, count of the raw cpool bytes that have been copied
932 // 0, OutOfMemory error
933 // -1, Internal error
934 int copy_cpool_bytes(int cpool_size,
935 SymbolHashMap* tbl,
936 unsigned char *bytes);
937
938 public:
939 // Verify
940 void verify_on(outputStream* st);
941
942 // Printing
943 void print_on(outputStream* st) const;
944 void print_value_on(outputStream* st) const;
945 void print_entry_on(int index, outputStream* st);
946
947 const char* internal_name() const { return "{constant pool}"; }
948
949 #ifndef PRODUCT
950 // Compile the world support
951 static void preload_and_initialize_all_classes(ConstantPool* constant_pool, TRAPS);
952 #endif
953 };
954
955 class SymbolHashMapEntry : public CHeapObj<mtSymbol> {
956 private:
957 unsigned int _hash; // 32-bit hash for item
958 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket
959 Symbol* _symbol; // 1-st part of the mapping: symbol => value
960 u2 _value; // 2-nd part of the mapping: symbol => value
961
962 public:
963 unsigned int hash() const { return _hash; }
964 void set_hash(unsigned int hash) { _hash = hash; }
965
966 SymbolHashMapEntry* next() const { return _next; }
967 void set_next(SymbolHashMapEntry* next) { _next = next; }
968
969 Symbol* symbol() const { return _symbol; }
970 void set_symbol(Symbol* sym) { _symbol = sym; }
971
972 u2 value() const { return _value; }
973 void set_value(u2 value) { _value = value; }
974
975 SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
976 : _hash(hash), _next(NULL), _symbol(symbol), _value(value) {}
977
978 }; // End SymbolHashMapEntry class
979
980
981 class SymbolHashMapBucket : public CHeapObj<mtSymbol> {
982
983 private:
984 SymbolHashMapEntry* _entry;
985
986 public:
987 SymbolHashMapEntry* entry() const { return _entry; }
988 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
989 void clear() { _entry = NULL; }
990
991 }; // End SymbolHashMapBucket class
992
993
994 class SymbolHashMap: public CHeapObj<mtSymbol> {
995
996 private:
997 // Default number of entries in the table
998 enum SymbolHashMap_Constants {
999 _Def_HashMap_Size = 256
1000 };
1001
1002 int _table_size;
1003 SymbolHashMapBucket* _buckets;
1004
1005 void initialize_table(int table_size);
1006
1007 public:
1008
1009 int table_size() const { return _table_size; }
1010
1011 SymbolHashMap() { initialize_table(_Def_HashMap_Size); }
1012 SymbolHashMap(int table_size) { initialize_table(table_size); }
1013
1014 // hash P(31) from Kernighan & Ritchie
1015 static unsigned int compute_hash(const char* str, int len) {
1016 unsigned int hash = 0;
1017 while (len-- > 0) {
1018 hash = 31*hash + (unsigned) *str;
1019 str++;
1020 }
1021 return hash;
1022 }
1023
1024 SymbolHashMapEntry* bucket(int i) {
1025 return _buckets[i].entry();
1026 }
1027
1028 void add_entry(Symbol* sym, u2 value);
1029 SymbolHashMapEntry* find_entry(Symbol* sym);
1030
1031 u2 symbol_to_value(Symbol* sym) {
1032 SymbolHashMapEntry *entry = find_entry(sym);
1033 return (entry == NULL) ? 0 : entry->value();
1034 }
1035
1036 ~SymbolHashMap();
1037 }; // End SymbolHashMap class
1038
1039 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP