1 /*
2 * Copyright (c) 1997, 2010, 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,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "interpreter/oopMapCache.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "prims/jvmtiRedefineClassesTrace.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/signature.hpp"
33
34 class OopMapCacheEntry: private InterpreterOopMap {
35 friend class InterpreterOopMap;
36 friend class OopMapForCacheEntry;
37 friend class OopMapCache;
38 friend class VerifyClosure;
39
40 protected:
41 // Initialization
42 void fill(methodHandle method, int bci);
43 // fills the bit mask for native calls
44 void fill_for_native(methodHandle method);
45 void set_mask(CellTypeState* vars, CellTypeState* stack, int stack_top);
46
47 // Deallocate bit masks and initialize fields
48 void flush();
49
50 private:
51 void allocate_bit_mask(); // allocates the bit mask on C heap f necessary
52 void deallocate_bit_mask(); // allocates the bit mask on C heap f necessary
53 bool verify_mask(CellTypeState *vars, CellTypeState *stack, int max_locals, int stack_top);
54
55 public:
56 OopMapCacheEntry() : InterpreterOopMap() {
57 #ifdef ASSERT
58 _resource_allocate_bit_mask = false;
59 #endif
60 }
61 };
62
63
64 // Implementation of OopMapForCacheEntry
65 // (subclass of GenerateOopMap, initializes an OopMapCacheEntry for a given method and bci)
66
67 class OopMapForCacheEntry: public GenerateOopMap {
68 OopMapCacheEntry *_entry;
69 int _bci;
70 int _stack_top;
71
72 virtual bool report_results() const { return false; }
73 virtual bool possible_gc_point (BytecodeStream *bcs);
74 virtual void fill_stackmap_prolog (int nof_gc_points);
75 virtual void fill_stackmap_epilog ();
76 virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
77 CellTypeState* vars,
78 CellTypeState* stack,
79 int stack_top);
80 virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars);
81
82 public:
83 OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry *entry);
84
85 // Computes stack map for (method,bci) and initialize entry
86 void compute_map(TRAPS);
87 int size();
88 };
89
90
91 OopMapForCacheEntry::OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry* entry) : GenerateOopMap(method) {
92 _bci = bci;
93 _entry = entry;
94 _stack_top = -1;
95 }
96
97
98 void OopMapForCacheEntry::compute_map(TRAPS) {
99 assert(!method()->is_native(), "cannot compute oop map for native methods");
100 // First check if it is a method where the stackmap is always empty
101 if (method()->code_size() == 0 || method()->max_locals() + method()->max_stack() == 0) {
102 _entry->set_mask_size(0);
103 } else {
104 ResourceMark rm;
105 GenerateOopMap::compute_map(CATCH);
106 result_for_basicblock(_bci);
107 }
108 }
109
110
111 bool OopMapForCacheEntry::possible_gc_point(BytecodeStream *bcs) {
112 return false; // We are not reporting any result. We call result_for_basicblock directly
113 }
114
115
116 void OopMapForCacheEntry::fill_stackmap_prolog(int nof_gc_points) {
117 // Do nothing
118 }
119
120
121 void OopMapForCacheEntry::fill_stackmap_epilog() {
122 // Do nothing
123 }
124
125
126 void OopMapForCacheEntry::fill_init_vars(GrowableArray<intptr_t> *init_vars) {
127 // Do nothing
128 }
129
130
131 void OopMapForCacheEntry::fill_stackmap_for_opcodes(BytecodeStream *bcs,
132 CellTypeState* vars,
133 CellTypeState* stack,
134 int stack_top) {
135 // Only interested in one specific bci
136 if (bcs->bci() == _bci) {
137 _entry->set_mask(vars, stack, stack_top);
138 _stack_top = stack_top;
139 }
140 }
141
142
143 int OopMapForCacheEntry::size() {
144 assert(_stack_top != -1, "compute_map must be called first");
145 return ((method()->is_static()) ? 0 : 1) + method()->max_locals() + _stack_top;
146 }
147
148
149 // Implementation of InterpreterOopMap and OopMapCacheEntry
150
151 class VerifyClosure : public OffsetClosure {
152 private:
153 OopMapCacheEntry* _entry;
154 bool _failed;
155
156 public:
157 VerifyClosure(OopMapCacheEntry* entry) { _entry = entry; _failed = false; }
158 void offset_do(int offset) { if (!_entry->is_oop(offset)) _failed = true; }
159 bool failed() const { return _failed; }
160 };
161
162 InterpreterOopMap::InterpreterOopMap() {
163 initialize();
164 #ifdef ASSERT
165 _resource_allocate_bit_mask = true;
166 #endif
167 }
168
169 InterpreterOopMap::~InterpreterOopMap() {
170 // The expection is that the bit mask was allocated
171 // last in this resource area. That would make the free of the
172 // bit_mask effective (see how FREE_RESOURCE_ARRAY does a free).
173 // If it was not allocated last, there is not a correctness problem
174 // but the space for the bit_mask is not freed.
175 assert(_resource_allocate_bit_mask, "Trying to free C heap space");
176 if (mask_size() > small_mask_limit) {
177 FREE_RESOURCE_ARRAY(uintptr_t, _bit_mask[0], mask_word_size());
178 }
179 }
180
181 bool InterpreterOopMap::is_empty() {
182 bool result = _method == NULL;
183 assert(_method != NULL || (_bci == 0 &&
184 (_mask_size == 0 || _mask_size == USHRT_MAX) &&
185 _bit_mask[0] == 0), "Should be completely empty");
186 return result;
187 }
188
189 void InterpreterOopMap::initialize() {
190 _method = NULL;
191 _mask_size = USHRT_MAX; // This value should cause a failure quickly
192 _bci = 0;
193 _expression_stack_size = 0;
194 for (int i = 0; i < N; i++) _bit_mask[i] = 0;
195 }
196
197
198 void InterpreterOopMap::oop_iterate(OopClosure *blk) {
199 if (method() != NULL) {
200 blk->do_oop((oop*) &_method);
201 }
202 }
203
204 void InterpreterOopMap::oop_iterate(OopClosure *blk, MemRegion mr) {
205 if (method() != NULL && mr.contains(&_method)) {
206 blk->do_oop((oop*) &_method);
207 }
208 }
209
210
211
212 void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) {
213 int n = number_of_entries();
214 int word_index = 0;
215 uintptr_t value = 0;
216 uintptr_t mask = 0;
217 // iterate over entries
218 for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
219 // get current word
220 if (mask == 0) {
221 value = bit_mask()[word_index++];
222 mask = 1;
223 }
224 // test for oop
225 if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);
226 }
227 }
228
229 void InterpreterOopMap::verify() {
230 // If we are doing mark sweep _method may not have a valid header
231 // $$$ This used to happen only for m/s collections; we might want to
232 // think of an appropriate generalization of this distinction.
233 guarantee(Universe::heap()->is_gc_active() || _method->is_oop_or_null(),
234 "invalid oop in oopMapCache");
235 }
236
237 #ifdef ENABLE_ZAP_DEAD_LOCALS
238
239 void InterpreterOopMap::iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure) {
240 int n = number_of_entries();
241 int word_index = 0;
242 uintptr_t value = 0;
243 uintptr_t mask = 0;
244 // iterate over entries
245 for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
246 // get current word
247 if (mask == 0) {
248 value = bit_mask()[word_index++];
249 mask = 1;
250 }
251 // test for dead values & oops, and for live values
252 if ((value & (mask << dead_bit_number)) != 0) dead_closure->offset_do(i); // call this for all dead values or oops
253 else if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i); // call this for all live oops
254 else value_closure->offset_do(i); // call this for all live values
255 }
256 }
257
258 #endif
259
260
261 void InterpreterOopMap::print() {
262 int n = number_of_entries();
263 tty->print("oop map for ");
264 method()->print_value();
265 tty->print(" @ %d = [%d] { ", bci(), n);
266 for (int i = 0; i < n; i++) {
267 #ifdef ENABLE_ZAP_DEAD_LOCALS
268 if (is_dead(i)) tty->print("%d+ ", i);
269 else
270 #endif
271 if (is_oop(i)) tty->print("%d ", i);
272 }
273 tty->print_cr("}");
274 }
275
276 class MaskFillerForNative: public NativeSignatureIterator {
277 private:
278 uintptr_t * _mask; // the bit mask to be filled
279 int _size; // the mask size in bits
280
281 void set_one(int i) {
282 i *= InterpreterOopMap::bits_per_entry;
283 assert(0 <= i && i < _size, "offset out of bounds");
284 _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
285 }
286
287 public:
288 void pass_int() { /* ignore */ }
289 void pass_long() { /* ignore */ }
290 void pass_float() { /* ignore */ }
291 void pass_double() { /* ignore */ }
292 void pass_object() { set_one(offset()); }
293
294 MaskFillerForNative(methodHandle method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
295 _mask = mask;
296 _size = size;
297 // initialize with 0
298 int i = (size + BitsPerWord - 1) / BitsPerWord;
299 while (i-- > 0) _mask[i] = 0;
300 }
301
302 void generate() {
303 NativeSignatureIterator::iterate();
304 }
305 };
306
307 bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
308 // Check mask includes map
309 VerifyClosure blk(this);
310 iterate_oop(&blk);
311 if (blk.failed()) return false;
312
313 // Check if map is generated correctly
314 // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
315 if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);
316
317 for(int i = 0; i < max_locals; i++) {
318 bool v1 = is_oop(i) ? true : false;
319 bool v2 = vars[i].is_reference() ? true : false;
320 assert(v1 == v2, "locals oop mask generation error");
321 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
322 #ifdef ENABLE_ZAP_DEAD_LOCALS
323 bool v3 = is_dead(i) ? true : false;
324 bool v4 = !vars[i].is_live() ? true : false;
325 assert(v3 == v4, "locals live mask generation error");
326 assert(!(v1 && v3), "dead value marked as oop");
327 #endif
328 }
329
330 if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }
331 for(int j = 0; j < stack_top; j++) {
332 bool v1 = is_oop(max_locals + j) ? true : false;
333 bool v2 = stack[j].is_reference() ? true : false;
334 assert(v1 == v2, "stack oop mask generation error");
335 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
336 #ifdef ENABLE_ZAP_DEAD_LOCALS
337 bool v3 = is_dead(max_locals + j) ? true : false;
338 bool v4 = !stack[j].is_live() ? true : false;
339 assert(v3 == v4, "stack live mask generation error");
340 assert(!(v1 && v3), "dead value marked as oop");
341 #endif
342 }
343 if (TraceOopMapGeneration && Verbose) tty->cr();
344 return true;
345 }
346
347 void OopMapCacheEntry::allocate_bit_mask() {
348 if (mask_size() > small_mask_limit) {
349 assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
350 _bit_mask[0] = (intptr_t)
351 NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size());
352 }
353 }
354
355 void OopMapCacheEntry::deallocate_bit_mask() {
356 if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
357 assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
358 "This bit mask should not be in the resource area");
359 FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0]);
360 debug_only(_bit_mask[0] = 0;)
361 }
362 }
363
364
365 void OopMapCacheEntry::fill_for_native(methodHandle mh) {
366 assert(mh->is_native(), "method must be native method");
367 set_mask_size(mh->size_of_parameters() * bits_per_entry);
368 allocate_bit_mask();
369 // fill mask for parameters
370 MaskFillerForNative mf(mh, bit_mask(), mask_size());
371 mf.generate();
372 }
373
374
375 void OopMapCacheEntry::fill(methodHandle method, int bci) {
376 HandleMark hm;
377 // Flush entry to deallocate an existing entry
378 flush();
379 set_method(method());
380 set_bci(bci);
381 if (method->is_native()) {
382 // Native method activations have oops only among the parameters and one
383 // extra oop following the parameters (the mirror for static native methods).
384 fill_for_native(method);
385 } else {
386 EXCEPTION_MARK;
387 OopMapForCacheEntry gen(method, bci, this);
388 gen.compute_map(CATCH);
389 }
390 #ifdef ASSERT
391 verify();
392 #endif
393 }
394
395
396 void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
397 // compute bit mask size
398 int max_locals = method()->max_locals();
399 int n_entries = max_locals + stack_top;
400 set_mask_size(n_entries * bits_per_entry);
401 allocate_bit_mask();
402 set_expression_stack_size(stack_top);
403
404 // compute bits
405 int word_index = 0;
406 uintptr_t value = 0;
407 uintptr_t mask = 1;
408
409 CellTypeState* cell = vars;
410 for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
411 // store last word
412 if (mask == 0) {
413 bit_mask()[word_index++] = value;
414 value = 0;
415 mask = 1;
416 }
417
418 // switch to stack when done with locals
419 if (entry_index == max_locals) {
420 cell = stack;
421 }
422
423 // set oop bit
424 if ( cell->is_reference()) {
425 value |= (mask << oop_bit_number );
426 }
427
428 #ifdef ENABLE_ZAP_DEAD_LOCALS
429 // set dead bit
430 if (!cell->is_live()) {
431 value |= (mask << dead_bit_number);
432 assert(!cell->is_reference(), "dead value marked as oop");
433 }
434 #endif
435 }
436
437 // make sure last word is stored
438 bit_mask()[word_index] = value;
439
440 // verify bit mask
441 assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
442
443
444 }
445
446 void OopMapCacheEntry::flush() {
447 deallocate_bit_mask();
448 initialize();
449 }
450
451
452 // Implementation of OopMapCache
453
454 #ifndef PRODUCT
455
456 static long _total_memory_usage = 0;
457
458 long OopMapCache::memory_usage() {
459 return _total_memory_usage;
460 }
461
462 #endif
463
464 void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
465 assert(_resource_allocate_bit_mask,
466 "Should not resource allocate the _bit_mask");
467 assert(from->method()->is_oop(), "MethodOop is bad");
468
469 set_method(from->method());
470 set_bci(from->bci());
471 set_mask_size(from->mask_size());
472 set_expression_stack_size(from->expression_stack_size());
473
474 // Is the bit mask contained in the entry?
475 if (from->mask_size() <= small_mask_limit) {
476 memcpy((void *)_bit_mask, (void *)from->_bit_mask,
477 mask_word_size() * BytesPerWord);
478 } else {
479 // The expectation is that this InterpreterOopMap is a recently created
480 // and empty. It is used to get a copy of a cached entry.
481 // If the bit mask has a value, it should be in the
482 // resource area.
483 assert(_bit_mask[0] == 0 ||
484 Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
485 "The bit mask should have been allocated from a resource area");
486 // Allocate the bit_mask from a Resource area for performance. Allocating
487 // from the C heap as is done for OopMapCache has a significant
488 // performance impact.
489 _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
490 assert(_bit_mask[0] != 0, "bit mask was not allocated");
491 memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
492 mask_word_size() * BytesPerWord);
493 }
494 }
495
496 inline unsigned int OopMapCache::hash_value_for(methodHandle method, int bci) {
497 // We use method->code_size() rather than method->identity_hash() below since
498 // the mark may not be present if a pointer to the method is already reversed.
499 return ((unsigned int) bci)
500 ^ ((unsigned int) method->max_locals() << 2)
501 ^ ((unsigned int) method->code_size() << 4)
502 ^ ((unsigned int) method->size_of_parameters() << 6);
503 }
504
505
506 OopMapCache::OopMapCache() :
507 _mut(Mutex::leaf, "An OopMapCache lock", true)
508 {
509 _array = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size);
510 // Cannot call flush for initialization, since flush
511 // will check if memory should be deallocated
512 for(int i = 0; i < _size; i++) _array[i].initialize();
513 NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
514 }
515
516
517 OopMapCache::~OopMapCache() {
518 assert(_array != NULL, "sanity check");
519 // Deallocate oop maps that are allocated out-of-line
520 flush();
521 // Deallocate array
522 NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
523 FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array);
524 }
525
526 OopMapCacheEntry* OopMapCache::entry_at(int i) const {
527 return &_array[i % _size];
528 }
529
530 void OopMapCache::flush() {
531 for (int i = 0; i < _size; i++) _array[i].flush();
532 }
533
534 void OopMapCache::flush_obsolete_entries() {
535 for (int i = 0; i < _size; i++)
536 if (!_array[i].is_empty() && _array[i].method()->is_old()) {
537 // Cache entry is occupied by an old redefined method and we don't want
538 // to pin it down so flush the entry.
539 RC_TRACE(0x08000000, ("flush: %s(%s): cached entry @%d",
540 _array[i].method()->name()->as_C_string(),
541 _array[i].method()->signature()->as_C_string(), i));
542
543 _array[i].flush();
544 }
545 }
546
547 void OopMapCache::oop_iterate(OopClosure *blk) {
548 for (int i = 0; i < _size; i++) _array[i].oop_iterate(blk);
549 }
550
551 void OopMapCache::oop_iterate(OopClosure *blk, MemRegion mr) {
552 for (int i = 0; i < _size; i++) _array[i].oop_iterate(blk, mr);
553 }
554
555 void OopMapCache::verify() {
556 for (int i = 0; i < _size; i++) _array[i].verify();
557 }
558
559 void OopMapCache::lookup(methodHandle method,
560 int bci,
561 InterpreterOopMap* entry_for) {
562 MutexLocker x(&_mut);
563
564 OopMapCacheEntry* entry = NULL;
565 int probe = hash_value_for(method, bci);
566
567 // Search hashtable for match
568 int i;
569 for(i = 0; i < _probe_depth; i++) {
570 entry = entry_at(probe + i);
571 if (entry->match(method, bci)) {
572 entry_for->resource_copy(entry);
573 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
574 return;
575 }
576 }
577
578 if (TraceOopMapGeneration) {
579 static int count = 0;
580 ResourceMark rm;
581 tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);
582 method->print_value(); tty->cr();
583 }
584
585 // Entry is not in hashtable.
586 // Compute entry and return it
587
588 if (method->should_not_be_cached()) {
589 // It is either not safe or not a good idea to cache this methodOop
590 // at this time. We give the caller of lookup() a copy of the
591 // interesting info via parameter entry_for, but we don't add it to
592 // the cache. See the gory details in methodOop.cpp.
593 compute_one_oop_map(method, bci, entry_for);
594 return;
595 }
596
597 // First search for an empty slot
598 for(i = 0; i < _probe_depth; i++) {
599 entry = entry_at(probe + i);
600 if (entry->is_empty()) {
601 entry->fill(method, bci);
602 entry_for->resource_copy(entry);
603 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
604 return;
605 }
606 }
607
608 if (TraceOopMapGeneration) {
609 ResourceMark rm;
610 tty->print_cr("*** collision in oopmap cache - flushing item ***");
611 }
612
613 // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
614 //entry_at(probe + _probe_depth - 1)->flush();
615 //for(i = _probe_depth - 1; i > 0; i--) {
616 // // Coping entry[i] = entry[i-1];
617 // OopMapCacheEntry *to = entry_at(probe + i);
618 // OopMapCacheEntry *from = entry_at(probe + i - 1);
619 // to->copy(from);
620 // }
621
622 assert(method->is_method(), "gaga");
623
624 entry = entry_at(probe + 0);
625 entry->fill(method, bci);
626
627 // Copy the newly cached entry to input parameter
628 entry_for->resource_copy(entry);
629
630 if (TraceOopMapGeneration) {
631 ResourceMark rm;
632 tty->print("Done with ");
633 method->print_value(); tty->cr();
634 }
635 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
636
637 return;
638 }
639
640 void OopMapCache::compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry) {
641 // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
642 OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1);
643 tmp->initialize();
644 tmp->fill(method, bci);
645 entry->resource_copy(tmp);
646 FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp);
647 }