1 /*
2 * Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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23 */
24
25 #ifndef SHARE_OOPS_CPCACHE_HPP
26 #define SHARE_OOPS_CPCACHE_HPP
27
28 #include "interpreter/bytecodes.hpp"
29 #include "memory/allocation.hpp"
30 #include "oops/array.hpp"
31 #include "oops/oopHandle.hpp"
32 #include "utilities/align.hpp"
33 #include "utilities/constantTag.hpp"
34
35 class PSPromotionManager;
36
37 // The ConstantPoolCache is not a cache! It is the resolution table that the
38 // interpreter uses to avoid going into the runtime and a way to access resolved
39 // values.
40
41 // A ConstantPoolCacheEntry describes an individual entry of the constant
42 // pool cache. There's 2 principal kinds of entries: field entries for in-
43 // stance & static field access, and method entries for invokes. Some of
44 // the entry layout is shared and looks as follows:
45 //
46 // bit number |31 0|
47 // bit length |-8--|-8--|---16----|
48 // --------------------------------
49 // _indices [ b2 | b1 | index ] index = constant_pool_index
50 // _f1 [ entry specific ] metadata ptr (method or klass)
51 // _f2 [ entry specific ] vtable or res_ref index, or vfinal method ptr
52 // _flags [tos|0|F=1|0|N|i|f|v|0 |0000|field_index] (for field entries)
53 // bit length [ 4 |1| 1 |1|1|1|1|1|1 |1 |-3-|----16-----]
54 // _flags [tos|0|F=0|S|A|I|f|0|vf|indy_rf|000|00000|psize] (for method entries)
55 // bit length [ 4 |1| 1 |1|1|1|1|1|1 |-4--|--8--|--8--]
56
57 // --------------------------------
58 //
59 // with:
60 // index = original constant pool index
61 // b1 = bytecode 1
62 // b2 = bytecode 2
63 // psize = parameters size (method entries only)
64 // field_index = index into field information in holder InstanceKlass
65 // The index max is 0xffff (max number of fields in constant pool)
66 // and is multiplied by (InstanceKlass::next_offset) when accessing.
67 // tos = TosState
68 // F = the entry is for a field (or F=0 for a method)
69 // A = call site has an appendix argument (loaded from resolved references)
70 // I = interface call is forced virtual (must use a vtable index or vfinal)
71 // f = field or method is final
72 // v = field is volatile
73 // vf = virtual but final (method entries only: is_vfinal())
74 // indy_rf = call site specifier method resolution failed
75 //
76 // The flags after TosState have the following interpretation:
77 // bit 27: 0 for fields, 1 for methods
78 // N flag true if field is marked flattenable (must never be null)
79 // i flag true if field is inlined (flattened)
80 // f flag true if field is marked final
81 // v flag true if field is volatile (only for fields)
82 // f2 flag true if f2 contains an oop (e.g., virtual final method)
83 // fv flag true if invokeinterface used for method in class Object
84 //
85 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 16 with the
86 // following mapping to the TosState states:
87 //
88 // btos: 0
89 // ztos: 1
90 // ctos: 2
91 // stos: 3
92 // itos: 4
93 // ltos: 5
94 // ftos: 6
95 // dtos: 7
96 // atos: 8
97 // vtos: 9
98 //
99 // Entry specific: field entries:
100 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index
101 // _f1 = field holder (as a java.lang.Class, not a Klass*)
102 // _f2 = field offset in bytes
103 // _flags = field type information, original FieldInfo index in field holder
104 // (field_index section)
105 //
106 // Entry specific: method entries:
107 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),
108 // original constant pool index
109 // _f1 = Method* for non-virtual calls, unused by virtual calls.
110 // for interface calls, which are essentially virtual but need a klass,
111 // contains Klass* for the corresponding interface.
112 // for invokedynamic and invokehandle, f1 contains the adapter method which
113 // manages the actual call. The appendix is stored in the ConstantPool
114 // resolved_references array.
115 // (upcoming metadata changes will move the appendix to a separate array)
116 // _f2 = vtable/itable index (or final Method*) for virtual calls only,
117 // unused by non-virtual. The is_vfinal flag indicates this is a
118 // method pointer for a final method, not an index.
119 // _flags = has local signature (MHs and indy),
120 // virtual final bit (vfinal),
121 // parameter size (psize section)
122 //
123 // Note: invokevirtual & invokespecial bytecodes can share the same constant
124 // pool entry and thus the same constant pool cache entry. All invoke
125 // bytecodes but invokevirtual use only _f1 and the corresponding b1
126 // bytecode, while invokevirtual uses only _f2 and the corresponding
127 // b2 bytecode. The value of _flags is shared for both types of entries.
128 //
129 // The fields are volatile so that they are stored in the order written in the
130 // source code. The _indices field with the bytecode must be written last.
131
132 class CallInfo;
133
134 class ConstantPoolCacheEntry {
135 friend class VMStructs;
136 friend class constantPoolCacheKlass;
137 friend class ConstantPool;
138 friend class InterpreterRuntime;
139
140 private:
141 volatile intx _indices; // constant pool index & rewrite bytecodes
142 Metadata* volatile _f1; // entry specific metadata field
143 volatile intx _f2; // entry specific int/metadata field
144 volatile intx _flags; // flags
145
146
147 void set_bytecode_1(Bytecodes::Code code);
148 void set_bytecode_2(Bytecodes::Code code);
149 void set_f1(Metadata* f1) {
150 Metadata* existing_f1 = _f1; // read once
151 assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");
152 _f1 = f1;
153 }
154 void release_set_f1(Metadata* f1);
155 void set_f2(intx f2) {
156 intx existing_f2 = _f2; // read once
157 assert(existing_f2 == 0 || existing_f2 == f2, "illegal field change");
158 _f2 = f2;
159 }
160 void set_f2_as_vfinal_method(Method* f2) {
161 assert(is_vfinal(), "flags must be set");
162 set_f2((intx)f2);
163 }
164 int make_flags(TosState state, int option_bits, int field_index_or_method_params);
165 void set_flags(intx flags) { _flags = flags; }
166 void set_field_flags(TosState field_type, int option_bits, int field_index) {
167 assert((field_index & field_index_mask) == field_index, "field_index in range");
168 set_flags(make_flags(field_type, option_bits | (1 << is_field_entry_shift), field_index));
169 }
170 void set_method_flags(TosState return_type, int option_bits, int method_params) {
171 assert((method_params & parameter_size_mask) == method_params, "method_params in range");
172 set_flags(make_flags(return_type, option_bits, method_params));
173 }
174
175 public:
176 // specific bit definitions for the flags field:
177 // (Note: the interpreter must use these definitions to access the CP cache.)
178 enum {
179 // high order bits are the TosState corresponding to field type or method return type
180 tos_state_bits = 4,
181 tos_state_mask = right_n_bits(tos_state_bits),
182 tos_state_shift = BitsPerInt - tos_state_bits, // see verify_tos_state_shift below
183 // misc. option bits; can be any bit position in [16..27]
184 is_field_entry_shift = 26, // (F) is it a field or a method?
185 has_local_signature_shift = 25, // (S) does the call site have a per-site signature (sig-poly methods)?
186 has_appendix_shift = 24, // (A) does the call site have an appendix argument?
187 is_flattenable_field_shift = 24, // (N) is the field flattenable (must never be null)
188 is_forced_virtual_shift = 23, // (I) is the interface reference forced to virtual mode?
189 is_flattened_field_shift = 23, // (i) is the value field flattened?
190 is_final_shift = 22, // (f) is the field or method final?
191 is_volatile_shift = 21, // (v) is the field volatile?
192 is_vfinal_shift = 20, // (vf) did the call resolve to a final method?
193 indy_resolution_failed_shift= 19, // (indy_rf) did call site specifier resolution fail ?
194 // low order bits give field index (for FieldInfo) or method parameter size:
195 field_index_bits = 16,
196 field_index_mask = right_n_bits(field_index_bits),
197 parameter_size_bits = 8, // subset of field_index_mask, range is 0..255
198 parameter_size_mask = right_n_bits(parameter_size_bits),
199 option_bits_mask = ~(((~0u) << tos_state_shift) | (field_index_mask | parameter_size_mask))
200 };
201
202 // specific bit definitions for the indices field:
203 enum {
204 cp_index_bits = 2*BitsPerByte,
205 cp_index_mask = right_n_bits(cp_index_bits),
206 bytecode_1_shift = cp_index_bits,
207 bytecode_1_mask = right_n_bits(BitsPerByte), // == (u1)0xFF
208 bytecode_2_shift = cp_index_bits + BitsPerByte,
209 bytecode_2_mask = right_n_bits(BitsPerByte) // == (u1)0xFF
210 };
211
212
213 // Initialization
214 void initialize_entry(int original_index); // initialize primary entry
215 void initialize_resolved_reference_index(int ref_index) {
216 assert(_f2 == 0, "set once"); // note: ref_index might be zero also
217 _f2 = ref_index;
218 }
219
220 void set_field( // sets entry to resolved field state
221 Bytecodes::Code get_code, // the bytecode used for reading the field
222 Bytecodes::Code put_code, // the bytecode used for writing the field
223 Klass* field_holder, // the object/klass holding the field
224 int orig_field_index, // the original field index in the field holder
225 int field_offset, // the field offset in words in the field holder
226 TosState field_type, // the (machine) field type
227 bool is_final, // the field is final
228 bool is_volatile, // the field is volatile
229 bool is_flattened, // the field is flattened (value field)
230 bool is_flattenable, // the field is flattenable (must never be null)
231 Klass* root_klass // needed by the GC to dirty the klass
232 );
233
234 private:
235 void set_direct_or_vtable_call(
236 Bytecodes::Code invoke_code, // the bytecode used for invoking the method
237 const methodHandle& method, // the method/prototype if any (NULL, otherwise)
238 int vtable_index, // the vtable index if any, else negative
239 bool sender_is_interface
240 );
241
242 public:
243 void set_direct_call( // sets entry to exact concrete method entry
244 Bytecodes::Code invoke_code, // the bytecode used for invoking the method
245 const methodHandle& method, // the method to call
246 bool sender_is_interface
247 );
248
249 void set_vtable_call( // sets entry to vtable index
250 Bytecodes::Code invoke_code, // the bytecode used for invoking the method
251 const methodHandle& method, // resolved method which declares the vtable index
252 int vtable_index // the vtable index
253 );
254
255 void set_itable_call(
256 Bytecodes::Code invoke_code, // the bytecode used; must be invokeinterface
257 Klass* referenced_klass, // the referenced klass in the InterfaceMethodref
258 const methodHandle& method, // the resolved interface method
259 int itable_index // index into itable for the method
260 );
261
262 void set_method_handle(
263 const constantPoolHandle& cpool, // holding constant pool (required for locking)
264 const CallInfo &call_info // Call link information
265 );
266
267 void set_dynamic_call(
268 const constantPoolHandle& cpool, // holding constant pool (required for locking)
269 const CallInfo &call_info // Call link information
270 );
271
272 // Common code for invokedynamic and MH invocations.
273
274 // The "appendix" is an optional call-site-specific parameter which is
275 // pushed by the JVM at the end of the argument list. This argument may
276 // be a MethodType for the MH.invokes and a CallSite for an invokedynamic
277 // instruction. However, its exact type and use depends on the Java upcall,
278 // which simply returns a compiled LambdaForm along with any reference
279 // that LambdaForm needs to complete the call. If the upcall returns a
280 // null appendix, the argument is not passed at all.
281 //
282 // The appendix is *not* represented in the signature of the symbolic
283 // reference for the call site, but (if present) it *is* represented in
284 // the Method* bound to the site. This means that static and dynamic
285 // resolution logic needs to make slightly different assessments about the
286 // number and types of arguments.
287 void set_method_handle_common(
288 const constantPoolHandle& cpool, // holding constant pool (required for locking)
289 Bytecodes::Code invoke_code, // _invokehandle or _invokedynamic
290 const CallInfo &call_info // Call link information
291 );
292
293 // Return TRUE if resolution failed and this thread got to record the failure
294 // status. Return FALSE if another thread succeeded or failed in resolving
295 // the method and recorded the success or failure before this thread had a
296 // chance to record its failure.
297 bool save_and_throw_indy_exc(const constantPoolHandle& cpool, int cpool_index,
298 int index, constantTag tag, TRAPS);
299
300 // invokedynamic and invokehandle call sites have an "appendix" item in the
301 // resolved references array.
302 Method* method_if_resolved(const constantPoolHandle& cpool);
303 oop appendix_if_resolved(const constantPoolHandle& cpool);
304
305 void set_parameter_size(int value);
306
307 // Which bytecode number (1 or 2) in the index field is valid for this bytecode?
308 // Returns -1 if neither is valid.
309 static int bytecode_number(Bytecodes::Code code) {
310 switch (code) {
311 case Bytecodes::_getstatic : // fall through
312 case Bytecodes::_getfield : // fall through
313 case Bytecodes::_invokespecial : // fall through
314 case Bytecodes::_invokestatic : // fall through
315 case Bytecodes::_invokehandle : // fall through
316 case Bytecodes::_invokedynamic : // fall through
317 case Bytecodes::_invokeinterface : return 1;
318 case Bytecodes::_putstatic : // fall through
319 case Bytecodes::_putfield : // fall through
320 case Bytecodes::_withfield : // fall through
321 case Bytecodes::_invokevirtual : return 2;
322 default : break;
323 }
324 return -1;
325 }
326
327 // Has this bytecode been resolved? Only valid for invokes and get/put field/static.
328 bool is_resolved(Bytecodes::Code code) const;
329
330 // Accessors
331 int indices() const { return _indices; }
332 int indices_ord() const;
333 int constant_pool_index() const { return (indices() & cp_index_mask); }
334 Bytecodes::Code bytecode_1() const;
335 Bytecodes::Code bytecode_2() const;
336 Metadata* f1_ord() const;
337 Method* f1_as_method() const;
338 Klass* f1_as_klass() const;
339 // Use the accessor f1() to acquire _f1's value. This is needed for
340 // example in BytecodeInterpreter::run(), where is_f1_null() is
341 // called to check if an invokedynamic call is resolved. This load
342 // of _f1 must be ordered with the loads performed by
343 // cache->main_entry_index().
344 bool is_f1_null() const; // classifies a CPC entry as unbound
345 int f2_as_index() const { assert(!is_vfinal(), ""); return (int) _f2; }
346 Method* f2_as_vfinal_method() const { assert(is_vfinal(), ""); return (Method*)_f2; }
347 Method* f2_as_interface_method() const;
348 int f2_as_offset() const { assert(is_field_entry(), ""); return (int)_f2; }
349 intx flags_ord() const;
350 int field_index() const { assert(is_field_entry(), ""); return (_flags & field_index_mask); }
351 int parameter_size() const { assert(is_method_entry(), ""); return (_flags & parameter_size_mask); }
352 bool is_volatile() const { return (_flags & (1 << is_volatile_shift)) != 0; }
353 bool is_final() const { return (_flags & (1 << is_final_shift)) != 0; }
354 bool is_flattened() const { return (_flags & (1 << is_flattened_field_shift)) != 0; }
355 bool is_forced_virtual() const { return (_flags & (1 << is_forced_virtual_shift)) != 0; }
356 bool is_vfinal() const { return (_flags & (1 << is_vfinal_shift)) != 0; }
357 bool indy_resolution_failed() const;
358 bool has_appendix() const;
359 bool has_local_signature() const;
360 bool is_method_entry() const { return (_flags & (1 << is_field_entry_shift)) == 0; }
361 bool is_field_entry() const { return (_flags & (1 << is_field_entry_shift)) != 0; }
362 bool is_long() const { return flag_state() == ltos; }
363 bool is_double() const { return flag_state() == dtos; }
364 bool is_flattenable() const { return (_flags & (1 << is_flattenable_field_shift)) != 0; }
365 TosState flag_state() const { assert((uint)number_of_states <= (uint)tos_state_mask+1, "");
366 return (TosState)((_flags >> tos_state_shift) & tos_state_mask); }
367 void set_indy_resolution_failed();
368
369 // Code generation support
370 static WordSize size() {
371 return in_WordSize(align_up((int)sizeof(ConstantPoolCacheEntry), wordSize) / wordSize);
372 }
373 static ByteSize size_in_bytes() { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }
374 static ByteSize indices_offset() { return byte_offset_of(ConstantPoolCacheEntry, _indices); }
375 static ByteSize f1_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f1); }
376 static ByteSize f2_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f2); }
377 static ByteSize flags_offset() { return byte_offset_of(ConstantPoolCacheEntry, _flags); }
378
379 #if INCLUDE_JVMTI
380 // RedefineClasses() API support:
381 // If this ConstantPoolCacheEntry refers to old_method then update it
382 // to refer to new_method.
383 // trace_name_printed is set to true if the current call has
384 // printed the klass name so that other routines in the adjust_*
385 // group don't print the klass name.
386 void adjust_method_entry(Method* old_method, Method* new_method,
387 bool* trace_name_printed);
388 bool check_no_old_or_obsolete_entries();
389 Method* get_interesting_method_entry();
390 #endif // INCLUDE_JVMTI
391
392 // Debugging & Printing
393 void print (outputStream* st, int index) const;
394 void verify(outputStream* st) const;
395
396 static void verify_tos_state_shift() {
397 // When shifting flags as a 32-bit int, make sure we don't need an extra mask for tos_state:
398 assert((((u4)-1 >> tos_state_shift) & ~tos_state_mask) == 0, "no need for tos_state mask");
399 }
400
401 void verify_just_initialized(bool f2_used);
402 void reinitialize(bool f2_used);
403 };
404
405
406 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache
407 // holds interpreter runtime information for all field access and invoke bytecodes. The cache
408 // is created and initialized before a class is actively used (i.e., initialized), the indivi-
409 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).
410
411 class ConstantPoolCache: public MetaspaceObj {
412 friend class VMStructs;
413 friend class MetadataFactory;
414 private:
415 // If you add a new field that points to any metaspace object, you
416 // must add this field to ConstantPoolCache::metaspace_pointers_do().
417 int _length;
418 ConstantPool* _constant_pool; // the corresponding constant pool
419
420 // The following fields need to be modified at runtime, so they cannot be
421 // stored in the ConstantPool, which is read-only.
422 // Array of resolved objects from the constant pool and map from resolved
423 // object index to original constant pool index
424 OopHandle _resolved_references;
425 Array<u2>* _reference_map;
426 // The narrowOop pointer to the archived resolved_references. Set at CDS dump
427 // time when caching java heap object is supported.
428 CDS_JAVA_HEAP_ONLY(narrowOop _archived_references;)
429
430 // Sizing
431 debug_only(friend class ClassVerifier;)
432
433 // Constructor
434 ConstantPoolCache(int length,
435 const intStack& inverse_index_map,
436 const intStack& invokedynamic_inverse_index_map,
437 const intStack& invokedynamic_references_map);
438
439 // Initialization
440 void initialize(const intArray& inverse_index_map,
441 const intArray& invokedynamic_inverse_index_map,
442 const intArray& invokedynamic_references_map);
443 public:
444 static ConstantPoolCache* allocate(ClassLoaderData* loader_data,
445 const intStack& cp_cache_map,
446 const intStack& invokedynamic_cp_cache_map,
447 const intStack& invokedynamic_references_map, TRAPS);
448
449 int length() const { return _length; }
450 void metaspace_pointers_do(MetaspaceClosure* it);
451 MetaspaceObj::Type type() const { return ConstantPoolCacheType; }
452
453 oop archived_references() NOT_CDS_JAVA_HEAP_RETURN_(NULL);
454 void set_archived_references(oop o) NOT_CDS_JAVA_HEAP_RETURN;
455
456 inline oop resolved_references();
457 void set_resolved_references(OopHandle s) { _resolved_references = s; }
458 Array<u2>* reference_map() const { return _reference_map; }
459 void set_reference_map(Array<u2>* o) { _reference_map = o; }
460
461 // Assembly code support
462 static int resolved_references_offset_in_bytes() { return offset_of(ConstantPoolCache, _resolved_references); }
463
464 // CDS support
465 void remove_unshareable_info();
466 void verify_just_initialized();
467 private:
468 void walk_entries_for_initialization(bool check_only);
469 void set_length(int length) { _length = length; }
470
471 static int header_size() { return sizeof(ConstantPoolCache) / wordSize; }
472 static int size(int length) { return align_metadata_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }
473 public:
474 int size() const { return size(length()); }
475 private:
476
477 // Helpers
478 ConstantPool** constant_pool_addr() { return &_constant_pool; }
479 ConstantPoolCacheEntry* base() const { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }
480
481 friend class constantPoolCacheKlass;
482 friend class ConstantPoolCacheEntry;
483
484 public:
485 // Accessors
486 void set_constant_pool(ConstantPool* pool) { _constant_pool = pool; }
487 ConstantPool* constant_pool() const { return _constant_pool; }
488 // Fetches the entry at the given index.
489 // In either case the index must not be encoded or byte-swapped in any way.
490 ConstantPoolCacheEntry* entry_at(int i) const {
491 assert(0 <= i && i < length(), "index out of bounds");
492 return base() + i;
493 }
494
495 // Code generation
496 static ByteSize base_offset() { return in_ByteSize(sizeof(ConstantPoolCache)); }
497 static ByteSize entry_offset(int raw_index) {
498 int index = raw_index;
499 return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);
500 }
501
502 #if INCLUDE_JVMTI
503 // RedefineClasses() API support:
504 // If any entry of this ConstantPoolCache points to any of
505 // old_methods, replace it with the corresponding new_method.
506 // trace_name_printed is set to true if the current call has
507 // printed the klass name so that other routines in the adjust_*
508 // group don't print the klass name.
509 void adjust_method_entries(bool* trace_name_printed);
510 bool check_no_old_or_obsolete_entries();
511 void dump_cache();
512 #endif // INCLUDE_JVMTI
513
514 // RedefineClasses support
515 DEBUG_ONLY(bool on_stack() { return false; })
516 void deallocate_contents(ClassLoaderData* data);
517 bool is_klass() const { return false; }
518
519 // Printing
520 void print_on(outputStream* st) const;
521 void print_value_on(outputStream* st) const;
522
523 const char* internal_name() const { return "{constant pool cache}"; }
524
525 // Verify
526 void verify_on(outputStream* st);
527 };
528
529 #endif // SHARE_OOPS_CPCACHE_HPP