1 /*
2 * Copyright (c) 1997, 2014, 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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
35
36 class OopMapCacheEntry: private InterpreterOopMap {
37 friend class InterpreterOopMap;
38 friend class OopMapForCacheEntry;
39 friend class OopMapCache;
40 friend class VerifyClosure;
41
42 protected:
43 // Initialization
44 void fill(methodHandle method, int bci);
45 // fills the bit mask for native calls
46 void fill_for_native(methodHandle method);
47 void set_mask(CellTypeState* vars, CellTypeState* stack, int stack_top);
48
49 // Deallocate bit masks and initialize fields
50 void flush();
51
52 private:
53 void allocate_bit_mask(); // allocates the bit mask on C heap f necessary
54 void deallocate_bit_mask(); // allocates the bit mask on C heap f necessary
55 bool verify_mask(CellTypeState *vars, CellTypeState *stack, int max_locals, int stack_top);
56
57 public:
58 OopMapCacheEntry() : InterpreterOopMap() {
59 #ifdef ASSERT
60 _resource_allocate_bit_mask = false;
61 #endif
62 }
63 };
64
65
66 // Implementation of OopMapForCacheEntry
67 // (subclass of GenerateOopMap, initializes an OopMapCacheEntry for a given method and bci)
68
69 class OopMapForCacheEntry: public GenerateOopMap {
70 OopMapCacheEntry *_entry;
71 int _bci;
72 int _stack_top;
73
74 virtual bool report_results() const { return false; }
75 virtual bool possible_gc_point (BytecodeStream *bcs);
76 virtual void fill_stackmap_prolog (int nof_gc_points);
77 virtual void fill_stackmap_epilog ();
78 virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
79 CellTypeState* vars,
80 CellTypeState* stack,
81 int stack_top);
82 virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars);
83
84 public:
85 OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry *entry);
86
87 // Computes stack map for (method,bci) and initialize entry
88 void compute_map(TRAPS);
89 int size();
90 };
91
92
93 OopMapForCacheEntry::OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry* entry) : GenerateOopMap(method) {
94 _bci = bci;
95 _entry = entry;
96 _stack_top = -1;
97 }
98
99
100 void OopMapForCacheEntry::compute_map(TRAPS) {
101 assert(!method()->is_native(), "cannot compute oop map for native methods");
102 // First check if it is a method where the stackmap is always empty
103 if (method()->code_size() == 0 || method()->max_locals() + method()->max_stack() == 0) {
104 _entry->set_mask_size(0);
105 } else {
106 ResourceMark rm;
107 GenerateOopMap::compute_map(CATCH);
108 result_for_basicblock(_bci);
109 }
110 }
111
112
113 bool OopMapForCacheEntry::possible_gc_point(BytecodeStream *bcs) {
114 return false; // We are not reporting any result. We call result_for_basicblock directly
115 }
116
117
118 void OopMapForCacheEntry::fill_stackmap_prolog(int nof_gc_points) {
119 // Do nothing
120 }
121
122
123 void OopMapForCacheEntry::fill_stackmap_epilog() {
124 // Do nothing
125 }
126
127
128 void OopMapForCacheEntry::fill_init_vars(GrowableArray<intptr_t> *init_vars) {
129 // Do nothing
130 }
131
132
133 void OopMapForCacheEntry::fill_stackmap_for_opcodes(BytecodeStream *bcs,
134 CellTypeState* vars,
135 CellTypeState* stack,
136 int stack_top) {
137 // Only interested in one specific bci
138 if (bcs->bci() == _bci) {
139 _entry->set_mask(vars, stack, stack_top);
140 _stack_top = stack_top;
141 }
142 }
143
144
145 int OopMapForCacheEntry::size() {
146 assert(_stack_top != -1, "compute_map must be called first");
147 return ((method()->is_static()) ? 0 : 1) + method()->max_locals() + _stack_top;
148 }
149
150
151 // Implementation of InterpreterOopMap and OopMapCacheEntry
152
153 class VerifyClosure : public OffsetClosure {
154 private:
155 OopMapCacheEntry* _entry;
156 bool _failed;
157
158 public:
159 VerifyClosure(OopMapCacheEntry* entry) { _entry = entry; _failed = false; }
160 void offset_do(int offset) { if (!_entry->is_oop(offset)) _failed = true; }
161 bool failed() const { return _failed; }
162 };
163
164 InterpreterOopMap::InterpreterOopMap() {
165 initialize();
166 #ifdef ASSERT
167 _resource_allocate_bit_mask = true;
168 #endif
169 }
170
171 InterpreterOopMap::~InterpreterOopMap() {
172 // The expection is that the bit mask was allocated
173 // last in this resource area. That would make the free of the
174 // bit_mask effective (see how FREE_RESOURCE_ARRAY does a free).
175 // If it was not allocated last, there is not a correctness problem
176 // but the space for the bit_mask is not freed.
177 assert(_resource_allocate_bit_mask, "Trying to free C heap space");
178 if (mask_size() > small_mask_limit) {
179 FREE_RESOURCE_ARRAY(uintptr_t, _bit_mask[0], mask_word_size());
180 }
181 }
182
183 bool InterpreterOopMap::is_empty() const {
184 bool result = _method == NULL;
185 assert(_method != NULL || (_bci == 0 &&
186 (_mask_size == 0 || _mask_size == USHRT_MAX) &&
187 _bit_mask[0] == 0), "Should be completely empty");
188 return result;
189 }
190
191 void InterpreterOopMap::initialize() {
192 _method = NULL;
193 _mask_size = USHRT_MAX; // This value should cause a failure quickly
194 _bci = 0;
195 _expression_stack_size = 0;
196 for (int i = 0; i < N; i++) _bit_mask[i] = 0;
197 }
198
199 void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) const {
200 int n = number_of_entries();
201 int word_index = 0;
202 uintptr_t value = 0;
203 uintptr_t mask = 0;
204 // iterate over entries
205 for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
206 // get current word
207 if (mask == 0) {
208 value = bit_mask()[word_index++];
209 mask = 1;
210 }
211 // test for oop
212 if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);
213 }
214 }
215
216
217 #ifdef ENABLE_ZAP_DEAD_LOCALS
218
219 void InterpreterOopMap::iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure) {
220 int n = number_of_entries();
221 int word_index = 0;
222 uintptr_t value = 0;
223 uintptr_t mask = 0;
224 // iterate over entries
225 for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
226 // get current word
227 if (mask == 0) {
228 value = bit_mask()[word_index++];
229 mask = 1;
230 }
231 // test for dead values & oops, and for live values
232 if ((value & (mask << dead_bit_number)) != 0) dead_closure->offset_do(i); // call this for all dead values or oops
233 else if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i); // call this for all live oops
234 else value_closure->offset_do(i); // call this for all live values
235 }
236 }
237
238 #endif
239
240
241 void InterpreterOopMap::print() const {
242 int n = number_of_entries();
243 tty->print("oop map for ");
244 method()->print_value();
245 tty->print(" @ %d = [%d] { ", bci(), n);
246 for (int i = 0; i < n; i++) {
247 if (is_dead(i)) tty->print("%d+ ", i);
248 else
249 if (is_oop(i)) tty->print("%d ", i);
250 }
251 tty->print_cr("}");
252 }
253
254 class MaskFillerForNative: public NativeSignatureIterator {
255 private:
256 uintptr_t * _mask; // the bit mask to be filled
257 int _size; // the mask size in bits
258
259 void set_one(int i) {
260 i *= InterpreterOopMap::bits_per_entry;
261 assert(0 <= i && i < _size, "offset out of bounds");
262 _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
263 }
264
265 public:
266 void pass_int() { /* ignore */ }
267 void pass_long() { /* ignore */ }
268 void pass_float() { /* ignore */ }
269 void pass_double() { /* ignore */ }
270 void pass_object() { set_one(offset()); }
271
272 MaskFillerForNative(methodHandle method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
273 _mask = mask;
274 _size = size;
275 // initialize with 0
276 int i = (size + BitsPerWord - 1) / BitsPerWord;
277 while (i-- > 0) _mask[i] = 0;
278 }
279
280 void generate() {
281 NativeSignatureIterator::iterate();
282 }
283 };
284
285 bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
286 // Check mask includes map
287 VerifyClosure blk(this);
288 iterate_oop(&blk);
289 if (blk.failed()) return false;
290
291 // Check if map is generated correctly
292 // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
293 if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);
294
295 for(int i = 0; i < max_locals; i++) {
296 bool v1 = is_oop(i) ? true : false;
297 bool v2 = vars[i].is_reference() ? true : false;
298 assert(v1 == v2, "locals oop mask generation error");
299 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
300 #ifdef ENABLE_ZAP_DEAD_LOCALS
301 bool v3 = is_dead(i) ? true : false;
302 bool v4 = !vars[i].is_live() ? true : false;
303 assert(v3 == v4, "locals live mask generation error");
304 assert(!(v1 && v3), "dead value marked as oop");
305 #endif
306 }
307
308 if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }
309 for(int j = 0; j < stack_top; j++) {
310 bool v1 = is_oop(max_locals + j) ? true : false;
311 bool v2 = stack[j].is_reference() ? true : false;
312 assert(v1 == v2, "stack oop mask generation error");
313 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
314 #ifdef ENABLE_ZAP_DEAD_LOCALS
315 bool v3 = is_dead(max_locals + j) ? true : false;
316 bool v4 = !stack[j].is_live() ? true : false;
317 assert(v3 == v4, "stack live mask generation error");
318 assert(!(v1 && v3), "dead value marked as oop");
319 #endif
320 }
321 if (TraceOopMapGeneration && Verbose) tty->cr();
322 return true;
323 }
324
325 void OopMapCacheEntry::allocate_bit_mask() {
326 if (mask_size() > small_mask_limit) {
327 assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
328 _bit_mask[0] = (intptr_t)
329 NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);
330 }
331 }
332
333 void OopMapCacheEntry::deallocate_bit_mask() {
334 if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
335 assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
336 "This bit mask should not be in the resource area");
337 FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0]);
338 debug_only(_bit_mask[0] = 0;)
339 }
340 }
341
342
343 void OopMapCacheEntry::fill_for_native(methodHandle mh) {
344 assert(mh->is_native(), "method must be native method");
345 set_mask_size(mh->size_of_parameters() * bits_per_entry);
346 allocate_bit_mask();
347 // fill mask for parameters
348 MaskFillerForNative mf(mh, bit_mask(), mask_size());
349 mf.generate();
350 }
351
352
353 void OopMapCacheEntry::fill(methodHandle method, int bci) {
354 HandleMark hm;
355 // Flush entry to deallocate an existing entry
356 flush();
357 set_method(method());
358 set_bci(bci);
359 if (method->is_native()) {
360 // Native method activations have oops only among the parameters and one
361 // extra oop following the parameters (the mirror for static native methods).
362 fill_for_native(method);
363 } else {
364 EXCEPTION_MARK;
365 OopMapForCacheEntry gen(method, bci, this);
366 gen.compute_map(CATCH);
367 }
368 }
369
370
371 void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
372 // compute bit mask size
373 int max_locals = method()->max_locals();
374 int n_entries = max_locals + stack_top;
375 set_mask_size(n_entries * bits_per_entry);
376 allocate_bit_mask();
377 set_expression_stack_size(stack_top);
378
379 // compute bits
380 int word_index = 0;
381 uintptr_t value = 0;
382 uintptr_t mask = 1;
383
384 CellTypeState* cell = vars;
385 for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
386 // store last word
387 if (mask == 0) {
388 bit_mask()[word_index++] = value;
389 value = 0;
390 mask = 1;
391 }
392
393 // switch to stack when done with locals
394 if (entry_index == max_locals) {
395 cell = stack;
396 }
397
398 // set oop bit
399 if ( cell->is_reference()) {
400 value |= (mask << oop_bit_number );
401 }
402
403 // set dead bit
404 if (!cell->is_live()) {
405 value |= (mask << dead_bit_number);
406 assert(!cell->is_reference(), "dead value marked as oop");
407 }
408 }
409
410 // make sure last word is stored
411 bit_mask()[word_index] = value;
412
413 // verify bit mask
414 assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
415
416
417 }
418
419 void OopMapCacheEntry::flush() {
420 deallocate_bit_mask();
421 initialize();
422 }
423
424
425 // Implementation of OopMapCache
426
427 #ifndef PRODUCT
428
429 static long _total_memory_usage = 0;
430
431 long OopMapCache::memory_usage() {
432 return _total_memory_usage;
433 }
434
435 #endif
436
437 void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
438 assert(_resource_allocate_bit_mask,
439 "Should not resource allocate the _bit_mask");
440
441 set_method(from->method());
442 set_bci(from->bci());
443 set_mask_size(from->mask_size());
444 set_expression_stack_size(from->expression_stack_size());
445
446 // Is the bit mask contained in the entry?
447 if (from->mask_size() <= small_mask_limit) {
448 memcpy((void *)_bit_mask, (void *)from->_bit_mask,
449 mask_word_size() * BytesPerWord);
450 } else {
451 // The expectation is that this InterpreterOopMap is a recently created
452 // and empty. It is used to get a copy of a cached entry.
453 // If the bit mask has a value, it should be in the
454 // resource area.
455 assert(_bit_mask[0] == 0 ||
456 Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
457 "The bit mask should have been allocated from a resource area");
458 // Allocate the bit_mask from a Resource area for performance. Allocating
459 // from the C heap as is done for OopMapCache has a significant
460 // performance impact.
461 _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
462 assert(_bit_mask[0] != 0, "bit mask was not allocated");
463 memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
464 mask_word_size() * BytesPerWord);
465 }
466 }
467
468 inline unsigned int OopMapCache::hash_value_for(methodHandle method, int bci) const {
469 // We use method->code_size() rather than method->identity_hash() below since
470 // the mark may not be present if a pointer to the method is already reversed.
471 return ((unsigned int) bci)
472 ^ ((unsigned int) method->max_locals() << 2)
473 ^ ((unsigned int) method->code_size() << 4)
474 ^ ((unsigned int) method->size_of_parameters() << 6);
475 }
476
477
478 OopMapCache::OopMapCache() :
479 _mut(Mutex::leaf, "An OopMapCache lock", true)
480 {
481 _array = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size, mtClass);
482 // Cannot call flush for initialization, since flush
483 // will check if memory should be deallocated
484 for(int i = 0; i < _size; i++) _array[i].initialize();
485 NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
486 }
487
488
489 OopMapCache::~OopMapCache() {
490 assert(_array != NULL, "sanity check");
491 // Deallocate oop maps that are allocated out-of-line
492 flush();
493 // Deallocate array
494 NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
495 FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array);
496 }
497
498 OopMapCacheEntry* OopMapCache::entry_at(int i) const {
499 return &_array[i % _size];
500 }
501
502 void OopMapCache::flush() {
503 for (int i = 0; i < _size; i++) _array[i].flush();
504 }
505
506 void OopMapCache::flush_obsolete_entries() {
507 for (int i = 0; i < _size; i++)
508 if (!_array[i].is_empty() && _array[i].method()->is_old()) {
509 // Cache entry is occupied by an old redefined method and we don't want
510 // to pin it down so flush the entry.
511 RC_TRACE(0x08000000, ("flush: %s(%s): cached entry @%d",
512 _array[i].method()->name()->as_C_string(),
513 _array[i].method()->signature()->as_C_string(), i));
514
515 _array[i].flush();
516 }
517 }
518
519 void OopMapCache::lookup(methodHandle method,
520 int bci,
521 InterpreterOopMap* entry_for) const {
522 MutexLocker x(&_mut);
523
524 OopMapCacheEntry* entry = NULL;
525 int probe = hash_value_for(method, bci);
526
527 // Search hashtable for match
528 int i;
529 for(i = 0; i < _probe_depth; i++) {
530 entry = entry_at(probe + i);
531 if (entry->match(method, bci)) {
532 entry_for->resource_copy(entry);
533 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
534 return;
535 }
536 }
537
538 if (TraceOopMapGeneration) {
539 static int count = 0;
540 ResourceMark rm;
541 tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);
542 method->print_value(); tty->cr();
543 }
544
545 // Entry is not in hashtable.
546 // Compute entry and return it
547
548 if (method->should_not_be_cached()) {
549 // It is either not safe or not a good idea to cache this Method*
550 // at this time. We give the caller of lookup() a copy of the
551 // interesting info via parameter entry_for, but we don't add it to
552 // the cache. See the gory details in Method*.cpp.
553 compute_one_oop_map(method, bci, entry_for);
554 return;
555 }
556
557 // First search for an empty slot
558 for(i = 0; i < _probe_depth; i++) {
559 entry = entry_at(probe + i);
560 if (entry->is_empty()) {
561 entry->fill(method, bci);
562 entry_for->resource_copy(entry);
563 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
564 return;
565 }
566 }
567
568 if (TraceOopMapGeneration) {
569 ResourceMark rm;
570 tty->print_cr("*** collision in oopmap cache - flushing item ***");
571 }
572
573 // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
574 //entry_at(probe + _probe_depth - 1)->flush();
575 //for(i = _probe_depth - 1; i > 0; i--) {
576 // // Coping entry[i] = entry[i-1];
577 // OopMapCacheEntry *to = entry_at(probe + i);
578 // OopMapCacheEntry *from = entry_at(probe + i - 1);
579 // to->copy(from);
580 // }
581
582 assert(method->is_method(), "gaga");
583
584 entry = entry_at(probe + 0);
585 entry->fill(method, bci);
586
587 // Copy the newly cached entry to input parameter
588 entry_for->resource_copy(entry);
589
590 if (TraceOopMapGeneration) {
591 ResourceMark rm;
592 tty->print("Done with ");
593 method->print_value(); tty->cr();
594 }
595 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
596
597 return;
598 }
599
600 void OopMapCache::compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry) {
601 // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
602 OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);
603 tmp->initialize();
604 tmp->fill(method, bci);
605 entry->resource_copy(tmp);
606 FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp);
607 }