1 /*
2 * Copyright (c) 1997, 2017, 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 "logging/log.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/oop.inline.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(const methodHandle& method, int bci);
43 // fills the bit mask for native calls
44 void fill_for_native(const 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(const 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(const 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() const {
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 void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) const {
198 int n = number_of_entries();
199 int word_index = 0;
200 uintptr_t value = 0;
201 uintptr_t mask = 0;
202 // iterate over entries
203 for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
204 // get current word
205 if (mask == 0) {
206 value = bit_mask()[word_index++];
207 mask = 1;
208 }
209 // test for oop
210 if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);
211 }
212 }
213
214 void InterpreterOopMap::print() const {
215 int n = number_of_entries();
216 tty->print("oop map for ");
217 method()->print_value();
218 tty->print(" @ %d = [%d] { ", bci(), n);
219 for (int i = 0; i < n; i++) {
220 if (is_dead(i)) tty->print("%d+ ", i);
221 else
222 if (is_oop(i)) tty->print("%d ", i);
223 }
224 tty->print_cr("}");
225 }
226
227 class MaskFillerForNative: public NativeSignatureIterator {
228 private:
229 uintptr_t * _mask; // the bit mask to be filled
230 int _size; // the mask size in bits
231
232 void set_one(int i) {
233 i *= InterpreterOopMap::bits_per_entry;
234 assert(0 <= i && i < _size, "offset out of bounds");
235 _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
236 }
237
238 public:
239 void pass_int() { /* ignore */ }
240 void pass_long() { /* ignore */ }
241 void pass_float() { /* ignore */ }
242 void pass_double() { /* ignore */ }
243 void pass_object() { set_one(offset()); }
244
245 MaskFillerForNative(const methodHandle& method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
246 _mask = mask;
247 _size = size;
248 // initialize with 0
249 int i = (size + BitsPerWord - 1) / BitsPerWord;
250 while (i-- > 0) _mask[i] = 0;
251 }
252
253 void generate() {
254 NativeSignatureIterator::iterate();
255 }
256 };
257
258 bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
259 // Check mask includes map
260 VerifyClosure blk(this);
261 iterate_oop(&blk);
262 if (blk.failed()) return false;
263
264 // Check if map is generated correctly
265 // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
266 if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);
267
268 for(int i = 0; i < max_locals; i++) {
269 bool v1 = is_oop(i) ? true : false;
270 bool v2 = vars[i].is_reference() ? true : false;
271 assert(v1 == v2, "locals oop mask generation error");
272 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
273 }
274
275 if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }
276 for(int j = 0; j < stack_top; j++) {
277 bool v1 = is_oop(max_locals + j) ? true : false;
278 bool v2 = stack[j].is_reference() ? true : false;
279 assert(v1 == v2, "stack oop mask generation error");
280 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
281 }
282 if (TraceOopMapGeneration && Verbose) tty->cr();
283 return true;
284 }
285
286 void OopMapCacheEntry::allocate_bit_mask() {
287 if (mask_size() > small_mask_limit) {
288 assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
289 _bit_mask[0] = (intptr_t)
290 NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);
291 }
292 }
293
294 void OopMapCacheEntry::deallocate_bit_mask() {
295 if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
296 assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
297 "This bit mask should not be in the resource area");
298 FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0]);
299 debug_only(_bit_mask[0] = 0;)
300 }
301 }
302
303
304 void OopMapCacheEntry::fill_for_native(const methodHandle& mh) {
305 assert(mh->is_native(), "method must be native method");
306 set_mask_size(mh->size_of_parameters() * bits_per_entry);
307 allocate_bit_mask();
308 // fill mask for parameters
309 MaskFillerForNative mf(mh, bit_mask(), mask_size());
310 mf.generate();
311 }
312
313
314 void OopMapCacheEntry::fill(const methodHandle& method, int bci) {
315 HandleMark hm;
316 // Flush entry to deallocate an existing entry
317 flush();
318 set_method(method());
319 set_bci(bci);
320 if (method->is_native()) {
321 // Native method activations have oops only among the parameters and one
322 // extra oop following the parameters (the mirror for static native methods).
323 fill_for_native(method);
324 } else {
325 EXCEPTION_MARK;
326 OopMapForCacheEntry gen(method, bci, this);
327 gen.compute_map(CATCH);
328 }
329 }
330
331
332 void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
333 // compute bit mask size
334 int max_locals = method()->max_locals();
335 int n_entries = max_locals + stack_top;
336 set_mask_size(n_entries * bits_per_entry);
337 allocate_bit_mask();
338 set_expression_stack_size(stack_top);
339
340 // compute bits
341 int word_index = 0;
342 uintptr_t value = 0;
343 uintptr_t mask = 1;
344
345 CellTypeState* cell = vars;
346 for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
347 // store last word
348 if (mask == 0) {
349 bit_mask()[word_index++] = value;
350 value = 0;
351 mask = 1;
352 }
353
354 // switch to stack when done with locals
355 if (entry_index == max_locals) {
356 cell = stack;
357 }
358
359 // set oop bit
360 if ( cell->is_reference()) {
361 value |= (mask << oop_bit_number );
362 }
363
364 // set dead bit
365 if (!cell->is_live()) {
366 value |= (mask << dead_bit_number);
367 assert(!cell->is_reference(), "dead value marked as oop");
368 }
369 }
370
371 // make sure last word is stored
372 bit_mask()[word_index] = value;
373
374 // verify bit mask
375 assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
376
377
378 }
379
380 void OopMapCacheEntry::flush() {
381 deallocate_bit_mask();
382 initialize();
383 }
384
385
386 // Implementation of OopMapCache
387
388 #ifndef PRODUCT
389
390 static long _total_memory_usage = 0;
391
392 long OopMapCache::memory_usage() {
393 return _total_memory_usage;
394 }
395
396 #endif
397
398 void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
399 assert(_resource_allocate_bit_mask,
400 "Should not resource allocate the _bit_mask");
401
402 set_method(from->method());
403 set_bci(from->bci());
404 set_mask_size(from->mask_size());
405 set_expression_stack_size(from->expression_stack_size());
406
407 // Is the bit mask contained in the entry?
408 if (from->mask_size() <= small_mask_limit) {
409 memcpy((void *)_bit_mask, (void *)from->_bit_mask,
410 mask_word_size() * BytesPerWord);
411 } else {
412 // The expectation is that this InterpreterOopMap is a recently created
413 // and empty. It is used to get a copy of a cached entry.
414 // If the bit mask has a value, it should be in the
415 // resource area.
416 assert(_bit_mask[0] == 0 ||
417 Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
418 "The bit mask should have been allocated from a resource area");
419 // Allocate the bit_mask from a Resource area for performance. Allocating
420 // from the C heap as is done for OopMapCache has a significant
421 // performance impact.
422 _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
423 assert(_bit_mask[0] != 0, "bit mask was not allocated");
424 memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
425 mask_word_size() * BytesPerWord);
426 }
427 }
428
429 inline unsigned int OopMapCache::hash_value_for(const methodHandle& method, int bci) const {
430 // We use method->code_size() rather than method->identity_hash() below since
431 // the mark may not be present if a pointer to the method is already reversed.
432 return ((unsigned int) bci)
433 ^ ((unsigned int) method->max_locals() << 2)
434 ^ ((unsigned int) method->code_size() << 4)
435 ^ ((unsigned int) method->size_of_parameters() << 6);
436 }
437
438
439 OopMapCache::OopMapCache() :
440 _mut(Mutex::leaf, "An OopMapCache lock", true)
441 {
442 _array = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size, mtClass);
443 // Cannot call flush for initialization, since flush
444 // will check if memory should be deallocated
445 for(int i = 0; i < _size; i++) _array[i].initialize();
446 NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
447 }
448
449
450 OopMapCache::~OopMapCache() {
451 assert(_array != NULL, "sanity check");
452 // Deallocate oop maps that are allocated out-of-line
453 flush();
454 // Deallocate array
455 NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
456 FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array);
457 }
458
459 OopMapCacheEntry* OopMapCache::entry_at(int i) const {
460 return &_array[i % _size];
461 }
462
463 void OopMapCache::flush() {
464 for (int i = 0; i < _size; i++) _array[i].flush();
465 }
466
467 void OopMapCache::flush_obsolete_entries() {
468 for (int i = 0; i < _size; i++)
469 if (!_array[i].is_empty() && _array[i].method()->is_old()) {
470 // Cache entry is occupied by an old redefined method and we don't want
471 // to pin it down so flush the entry.
472 if (log_is_enabled(Debug, redefine, class, oopmap)) {
473 ResourceMark rm;
474 log_debug(redefine, class, oopmap)
475 ("flush: %s(%s): cached entry @%d",
476 _array[i].method()->name()->as_C_string(), _array[i].method()->signature()->as_C_string(), i);
477 }
478 _array[i].flush();
479 }
480 }
481
482 void OopMapCache::lookup(const methodHandle& method,
483 int bci,
484 InterpreterOopMap* entry_for) const {
485 MutexLocker x(&_mut);
486
487 OopMapCacheEntry* entry = NULL;
488 int probe = hash_value_for(method, bci);
489
490 // Search hashtable for match
491 int i;
492 for(i = 0; i < _probe_depth; i++) {
493 entry = entry_at(probe + i);
494 if (entry->match(method, bci)) {
495 entry_for->resource_copy(entry);
496 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
497 return;
498 }
499 }
500
501 if (TraceOopMapGeneration) {
502 static int count = 0;
503 ResourceMark rm;
504 tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);
505 method->print_value(); tty->cr();
506 }
507
508 // Entry is not in hashtable.
509 // Compute entry and return it
510
511 if (method->should_not_be_cached()) {
512 // It is either not safe or not a good idea to cache this Method*
513 // at this time. We give the caller of lookup() a copy of the
514 // interesting info via parameter entry_for, but we don't add it to
515 // the cache. See the gory details in Method*.cpp.
516 compute_one_oop_map(method, bci, entry_for);
517 return;
518 }
519
520 // First search for an empty slot
521 for(i = 0; i < _probe_depth; i++) {
522 entry = entry_at(probe + i);
523 if (entry->is_empty()) {
524 entry->fill(method, bci);
525 entry_for->resource_copy(entry);
526 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
527 return;
528 }
529 }
530
531 if (TraceOopMapGeneration) {
532 ResourceMark rm;
533 tty->print_cr("*** collision in oopmap cache - flushing item ***");
534 }
535
536 // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
537 //entry_at(probe + _probe_depth - 1)->flush();
538 //for(i = _probe_depth - 1; i > 0; i--) {
539 // // Coping entry[i] = entry[i-1];
540 // OopMapCacheEntry *to = entry_at(probe + i);
541 // OopMapCacheEntry *from = entry_at(probe + i - 1);
542 // to->copy(from);
543 // }
544
545 assert(method->is_method(), "gaga");
546
547 entry = entry_at(probe + 0);
548 entry->fill(method, bci);
549
550 // Copy the newly cached entry to input parameter
551 entry_for->resource_copy(entry);
552
553 if (TraceOopMapGeneration) {
554 ResourceMark rm;
555 tty->print("Done with ");
556 method->print_value(); tty->cr();
557 }
558 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
559
560 return;
561 }
562
563 void OopMapCache::compute_one_oop_map(const methodHandle& method, int bci, InterpreterOopMap* entry) {
564 // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
565 OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);
566 tmp->initialize();
567 tmp->fill(method, bci);
568 entry->resource_copy(tmp);
569 FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp);
570 }