1 /*
2 * Copyright (c) 1997, 2012, 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() {
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) {
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() {
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 #ifdef ENABLE_ZAP_DEAD_LOCALS
248 if (is_dead(i)) tty->print("%d+ ", i);
249 else
250 #endif
251 if (is_oop(i)) tty->print("%d ", i);
252 }
253 tty->print_cr("}");
254 }
255
256 class MaskFillerForNative: public NativeSignatureIterator {
257 private:
258 uintptr_t * _mask; // the bit mask to be filled
259 int _size; // the mask size in bits
260
261 void set_one(int i) {
262 i *= InterpreterOopMap::bits_per_entry;
263 assert(0 <= i && i < _size, "offset out of bounds");
264 _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
265 }
266
267 public:
268 void pass_int() { /* ignore */ }
269 void pass_long() { /* ignore */ }
270 void pass_float() { /* ignore */ }
271 void pass_double() { /* ignore */ }
272 void pass_object() { set_one(offset()); }
273
274 MaskFillerForNative(methodHandle method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
275 _mask = mask;
276 _size = size;
277 // initialize with 0
278 int i = (size + BitsPerWord - 1) / BitsPerWord;
279 while (i-- > 0) _mask[i] = 0;
280 }
281
282 void generate() {
283 NativeSignatureIterator::iterate();
284 }
285 };
286
287 bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
288 // Check mask includes map
289 VerifyClosure blk(this);
290 iterate_oop(&blk);
291 if (blk.failed()) return false;
292
293 // Check if map is generated correctly
294 // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
295 if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);
296
297 for(int i = 0; i < max_locals; i++) {
298 bool v1 = is_oop(i) ? true : false;
299 bool v2 = vars[i].is_reference() ? true : false;
300 assert(v1 == v2, "locals oop mask generation error");
301 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
302 #ifdef ENABLE_ZAP_DEAD_LOCALS
303 bool v3 = is_dead(i) ? true : false;
304 bool v4 = !vars[i].is_live() ? true : false;
305 assert(v3 == v4, "locals live mask generation error");
306 assert(!(v1 && v3), "dead value marked as oop");
307 #endif
308 }
309
310 if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }
311 for(int j = 0; j < stack_top; j++) {
312 bool v1 = is_oop(max_locals + j) ? true : false;
313 bool v2 = stack[j].is_reference() ? true : false;
314 assert(v1 == v2, "stack oop mask generation error");
315 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
316 #ifdef ENABLE_ZAP_DEAD_LOCALS
317 bool v3 = is_dead(max_locals + j) ? true : false;
318 bool v4 = !stack[j].is_live() ? true : false;
319 assert(v3 == v4, "stack live mask generation error");
320 assert(!(v1 && v3), "dead value marked as oop");
321 #endif
322 }
323 if (TraceOopMapGeneration && Verbose) tty->cr();
324 return true;
325 }
326
327 void OopMapCacheEntry::allocate_bit_mask() {
328 if (mask_size() > small_mask_limit) {
329 assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
330 _bit_mask[0] = (intptr_t)
331 NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);
332 }
333 }
334
335 void OopMapCacheEntry::deallocate_bit_mask() {
336 if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
337 assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
338 "This bit mask should not be in the resource area");
339 FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0], mtClass);
340 debug_only(_bit_mask[0] = 0;)
341 }
342 }
343
344
345 void OopMapCacheEntry::fill_for_native(methodHandle mh) {
346 assert(mh->is_native(), "method must be native method");
347 set_mask_size(mh->size_of_parameters() * bits_per_entry);
348 allocate_bit_mask();
349 // fill mask for parameters
350 MaskFillerForNative mf(mh, bit_mask(), mask_size());
351 mf.generate();
352 }
353
354
355 void OopMapCacheEntry::fill(methodHandle method, int bci) {
356 HandleMark hm;
357 // Flush entry to deallocate an existing entry
358 flush();
359 set_method(method());
360 set_bci(bci);
361 if (method->is_native()) {
362 // Native method activations have oops only among the parameters and one
363 // extra oop following the parameters (the mirror for static native methods).
364 fill_for_native(method);
365 } else {
366 EXCEPTION_MARK;
367 OopMapForCacheEntry gen(method, bci, this);
368 gen.compute_map(CATCH);
369 }
370 }
371
372
373 void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
374 // compute bit mask size
375 int max_locals = method()->max_locals();
376 int n_entries = max_locals + stack_top;
377 set_mask_size(n_entries * bits_per_entry);
378 allocate_bit_mask();
379 set_expression_stack_size(stack_top);
380
381 // compute bits
382 int word_index = 0;
383 uintptr_t value = 0;
384 uintptr_t mask = 1;
385
386 CellTypeState* cell = vars;
387 for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
388 // store last word
389 if (mask == 0) {
390 bit_mask()[word_index++] = value;
391 value = 0;
392 mask = 1;
393 }
394
395 // switch to stack when done with locals
396 if (entry_index == max_locals) {
397 cell = stack;
398 }
399
400 // set oop bit
401 if ( cell->is_reference()) {
402 value |= (mask << oop_bit_number );
403 }
404
405 #ifdef ENABLE_ZAP_DEAD_LOCALS
406 // set dead bit
407 if (!cell->is_live()) {
408 value |= (mask << dead_bit_number);
409 assert(!cell->is_reference(), "dead value marked as oop");
410 }
411 #endif
412 }
413
414 // make sure last word is stored
415 bit_mask()[word_index] = value;
416
417 // verify bit mask
418 assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
419
420
421 }
422
423 void OopMapCacheEntry::flush() {
424 deallocate_bit_mask();
425 initialize();
426 }
427
428
429 // Implementation of OopMapCache
430
431 #ifndef PRODUCT
432
433 static long _total_memory_usage = 0;
434
435 long OopMapCache::memory_usage() {
436 return _total_memory_usage;
437 }
438
439 #endif
440
441 void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
442 assert(_resource_allocate_bit_mask,
443 "Should not resource allocate the _bit_mask");
444
445 set_method(from->method());
446 set_bci(from->bci());
447 set_mask_size(from->mask_size());
448 set_expression_stack_size(from->expression_stack_size());
449
450 // Is the bit mask contained in the entry?
451 if (from->mask_size() <= small_mask_limit) {
452 memcpy((void *)_bit_mask, (void *)from->_bit_mask,
453 mask_word_size() * BytesPerWord);
454 } else {
455 // The expectation is that this InterpreterOopMap is a recently created
456 // and empty. It is used to get a copy of a cached entry.
457 // If the bit mask has a value, it should be in the
458 // resource area.
459 assert(_bit_mask[0] == 0 ||
460 Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
461 "The bit mask should have been allocated from a resource area");
462 // Allocate the bit_mask from a Resource area for performance. Allocating
463 // from the C heap as is done for OopMapCache has a significant
464 // performance impact.
465 _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
466 assert(_bit_mask[0] != 0, "bit mask was not allocated");
467 memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
468 mask_word_size() * BytesPerWord);
469 }
470 }
471
472 inline unsigned int OopMapCache::hash_value_for(methodHandle method, int bci) {
473 // We use method->code_size() rather than method->identity_hash() below since
474 // the mark may not be present if a pointer to the method is already reversed.
475 return ((unsigned int) bci)
476 ^ ((unsigned int) method->max_locals() << 2)
477 ^ ((unsigned int) method->code_size() << 4)
478 ^ ((unsigned int) method->size_of_parameters() << 6);
479 }
480
481
482 OopMapCache::OopMapCache() :
483 _mut(Mutex::leaf, "An OopMapCache lock", true)
484 {
485 _array = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size, mtClass);
486 // Cannot call flush for initialization, since flush
487 // will check if memory should be deallocated
488 for(int i = 0; i < _size; i++) _array[i].initialize();
489 NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
490 }
491
492
493 OopMapCache::~OopMapCache() {
494 assert(_array != NULL, "sanity check");
495 // Deallocate oop maps that are allocated out-of-line
496 flush();
497 // Deallocate array
498 NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
499 FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array, mtClass);
500 }
501
502 OopMapCacheEntry* OopMapCache::entry_at(int i) const {
503 return &_array[i % _size];
504 }
505
506 void OopMapCache::flush() {
507 for (int i = 0; i < _size; i++) _array[i].flush();
508 }
509
510 void OopMapCache::flush_obsolete_entries() {
511 for (int i = 0; i < _size; i++)
512 if (!_array[i].is_empty() && _array[i].method()->is_old()) {
513 // Cache entry is occupied by an old redefined method and we don't want
514 // to pin it down so flush the entry.
515 RC_TRACE(0x08000000, ("flush: %s(%s): cached entry @%d",
516 _array[i].method()->name()->as_C_string(),
517 _array[i].method()->signature()->as_C_string(), i));
518
519 _array[i].flush();
520 }
521 }
522
523 void OopMapCache::lookup(methodHandle method,
524 int bci,
525 InterpreterOopMap* entry_for) {
526 MutexLocker x(&_mut);
527
528 OopMapCacheEntry* entry = NULL;
529 int probe = hash_value_for(method, bci);
530
531 // Search hashtable for match
532 int i;
533 for(i = 0; i < _probe_depth; i++) {
534 entry = entry_at(probe + i);
535 if (entry->match(method, bci)) {
536 entry_for->resource_copy(entry);
537 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
538 return;
539 }
540 }
541
542 if (TraceOopMapGeneration) {
543 static int count = 0;
544 ResourceMark rm;
545 tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);
546 method->print_value(); tty->cr();
547 }
548
549 // Entry is not in hashtable.
550 // Compute entry and return it
551
552 if (method->should_not_be_cached()) {
553 // It is either not safe or not a good idea to cache this Method*
554 // at this time. We give the caller of lookup() a copy of the
555 // interesting info via parameter entry_for, but we don't add it to
556 // the cache. See the gory details in Method*.cpp.
557 compute_one_oop_map(method, bci, entry_for);
558 return;
559 }
560
561 // First search for an empty slot
562 for(i = 0; i < _probe_depth; i++) {
563 entry = entry_at(probe + i);
564 if (entry->is_empty()) {
565 entry->fill(method, bci);
566 entry_for->resource_copy(entry);
567 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
568 return;
569 }
570 }
571
572 if (TraceOopMapGeneration) {
573 ResourceMark rm;
574 tty->print_cr("*** collision in oopmap cache - flushing item ***");
575 }
576
577 // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
578 //entry_at(probe + _probe_depth - 1)->flush();
579 //for(i = _probe_depth - 1; i > 0; i--) {
580 // // Coping entry[i] = entry[i-1];
581 // OopMapCacheEntry *to = entry_at(probe + i);
582 // OopMapCacheEntry *from = entry_at(probe + i - 1);
583 // to->copy(from);
584 // }
585
586 assert(method->is_method(), "gaga");
587
588 entry = entry_at(probe + 0);
589 entry->fill(method, bci);
590
591 // Copy the newly cached entry to input parameter
592 entry_for->resource_copy(entry);
593
594 if (TraceOopMapGeneration) {
595 ResourceMark rm;
596 tty->print("Done with ");
597 method->print_value(); tty->cr();
598 }
599 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
600
601 return;
602 }
603
604 void OopMapCache::compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry) {
605 // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
606 OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);
607 tmp->initialize();
608 tmp->fill(method, bci);
609 entry->resource_copy(tmp);
610 FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp, mtInternal);
611 }