1 /*
2 * Copyright (c) 2018, 2021, Red Hat, Inc. 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 "classfile/javaClasses.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.hpp"
30 #include "gc/shenandoah/shenandoahHeap.hpp"
31 #include "gc/shenandoah/shenandoahRuntime.hpp"
32 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
33 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
34 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
35 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
36 #include "gc/shenandoah/mode/shenandoahMode.hpp"
37 #include "opto/arraycopynode.hpp"
38 #include "opto/escape.hpp"
39 #include "opto/graphKit.hpp"
40 #include "opto/idealKit.hpp"
41 #include "opto/macro.hpp"
42 #include "opto/movenode.hpp"
43 #include "opto/narrowptrnode.hpp"
44 #include "opto/rootnode.hpp"
45 #include "opto/runtime.hpp"
46
47 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
48 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
49 }
50
51 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
52 : _iu_barriers(new (comp_arena) GrowableArray<ShenandoahIUBarrierNode*>(comp_arena, 8, 0, nullptr)),
53 _load_reference_barriers(new (comp_arena) GrowableArray<ShenandoahLoadReferenceBarrierNode*>(comp_arena, 8, 0, nullptr)) {
54 }
55
56 int ShenandoahBarrierSetC2State::iu_barriers_count() const {
57 return _iu_barriers->length();
58 }
59
60 ShenandoahIUBarrierNode* ShenandoahBarrierSetC2State::iu_barrier(int idx) const {
61 return _iu_barriers->at(idx);
62 }
63
64 void ShenandoahBarrierSetC2State::add_iu_barrier(ShenandoahIUBarrierNode* n) {
65 assert(!_iu_barriers->contains(n), "duplicate entry in barrier list");
66 _iu_barriers->append(n);
67 }
68
69 void ShenandoahBarrierSetC2State::remove_iu_barrier(ShenandoahIUBarrierNode* n) {
70 _iu_barriers->remove_if_existing(n);
71 }
72
73 int ShenandoahBarrierSetC2State::load_reference_barriers_count() const {
74 return _load_reference_barriers->length();
75 }
76
77 ShenandoahLoadReferenceBarrierNode* ShenandoahBarrierSetC2State::load_reference_barrier(int idx) const {
78 return _load_reference_barriers->at(idx);
79 }
80
81 void ShenandoahBarrierSetC2State::add_load_reference_barrier(ShenandoahLoadReferenceBarrierNode * n) {
82 assert(!_load_reference_barriers->contains(n), "duplicate entry in barrier list");
83 _load_reference_barriers->append(n);
84 }
85
86 void ShenandoahBarrierSetC2State::remove_load_reference_barrier(ShenandoahLoadReferenceBarrierNode * n) {
87 if (_load_reference_barriers->contains(n)) {
88 _load_reference_barriers->remove(n);
89 }
90 }
91
92 Node* ShenandoahBarrierSetC2::shenandoah_iu_barrier(GraphKit* kit, Node* obj) const {
93 if (ShenandoahIUBarrier) {
94 return kit->gvn().transform(new ShenandoahIUBarrierNode(obj));
95 }
96 return obj;
97 }
98
99 #define __ kit->
100
101 bool ShenandoahBarrierSetC2::satb_can_remove_pre_barrier(GraphKit* kit, PhaseTransform* phase, Node* adr,
102 BasicType bt, uint adr_idx) const {
103 intptr_t offset = 0;
104 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
105 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
106
107 if (offset == Type::OffsetBot) {
108 return false; // cannot unalias unless there are precise offsets
109 }
110
111 if (alloc == nullptr) {
112 return false; // No allocation found
113 }
114
115 intptr_t size_in_bytes = type2aelembytes(bt);
116
117 Node* mem = __ memory(adr_idx); // start searching here...
118
119 for (int cnt = 0; cnt < 50; cnt++) {
120
121 if (mem->is_Store()) {
122
123 Node* st_adr = mem->in(MemNode::Address);
124 intptr_t st_offset = 0;
125 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
126
127 if (st_base == nullptr) {
128 break; // inscrutable pointer
129 }
130
131 // Break we have found a store with same base and offset as ours so break
132 if (st_base == base && st_offset == offset) {
133 break;
134 }
135
136 if (st_offset != offset && st_offset != Type::OffsetBot) {
137 const int MAX_STORE = BytesPerLong;
138 if (st_offset >= offset + size_in_bytes ||
139 st_offset <= offset - MAX_STORE ||
140 st_offset <= offset - mem->as_Store()->memory_size()) {
141 // Success: The offsets are provably independent.
142 // (You may ask, why not just test st_offset != offset and be done?
143 // The answer is that stores of different sizes can co-exist
144 // in the same sequence of RawMem effects. We sometimes initialize
145 // a whole 'tile' of array elements with a single jint or jlong.)
146 mem = mem->in(MemNode::Memory);
147 continue; // advance through independent store memory
148 }
149 }
150
151 if (st_base != base
152 && MemNode::detect_ptr_independence(base, alloc, st_base,
153 AllocateNode::Ideal_allocation(st_base, phase),
154 phase)) {
155 // Success: The bases are provably independent.
156 mem = mem->in(MemNode::Memory);
157 continue; // advance through independent store memory
158 }
159 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
160
161 InitializeNode* st_init = mem->in(0)->as_Initialize();
162 AllocateNode* st_alloc = st_init->allocation();
163
164 // Make sure that we are looking at the same allocation site.
165 // The alloc variable is guaranteed to not be null here from earlier check.
166 if (alloc == st_alloc) {
167 // Check that the initialization is storing null so that no previous store
168 // has been moved up and directly write a reference
169 Node* captured_store = st_init->find_captured_store(offset,
170 type2aelembytes(T_OBJECT),
171 phase);
172 if (captured_store == nullptr || captured_store == st_init->zero_memory()) {
173 return true;
174 }
175 }
176 }
177
178 // Unless there is an explicit 'continue', we must bail out here,
179 // because 'mem' is an inscrutable memory state (e.g., a call).
180 break;
181 }
182
183 return false;
184 }
185
186 #undef __
187 #define __ ideal.
188
189 void ShenandoahBarrierSetC2::satb_write_barrier_pre(GraphKit* kit,
190 bool do_load,
191 Node* obj,
192 Node* adr,
193 uint alias_idx,
194 Node* val,
195 const TypeOopPtr* val_type,
196 Node* pre_val,
197 BasicType bt) const {
198 // Some sanity checks
199 // Note: val is unused in this routine.
200
201 if (do_load) {
202 // We need to generate the load of the previous value
203 assert(adr != nullptr, "where are loading from?");
204 assert(pre_val == nullptr, "loaded already?");
205 assert(val_type != nullptr, "need a type");
206
207 if (ReduceInitialCardMarks
208 && satb_can_remove_pre_barrier(kit, &kit->gvn(), adr, bt, alias_idx)) {
209 return;
210 }
211
212 } else {
213 // In this case both val_type and alias_idx are unused.
214 assert(pre_val != nullptr, "must be loaded already");
215 // Nothing to be done if pre_val is null.
216 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
217 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
218 }
219 assert(bt == T_OBJECT, "or we shouldn't be here");
220
221 IdealKit ideal(kit, true);
222
223 Node* tls = __ thread(); // ThreadLocalStorage
224
225 Node* no_base = __ top();
226 Node* zero = __ ConI(0);
227 Node* zeroX = __ ConX(0);
228
229 float likely = PROB_LIKELY(0.999);
230 float unlikely = PROB_UNLIKELY(0.999);
231
232 // Offsets into the thread
233 const int index_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset());
234 const int buffer_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
235
236 // Now the actual pointers into the thread
237 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
238 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
239
240 // Now some of the values
241 Node* marking;
242 Node* gc_state = __ AddP(no_base, tls, __ ConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset())));
243 Node* ld = __ load(__ ctrl(), gc_state, TypeInt::BYTE, T_BYTE, Compile::AliasIdxRaw);
244 marking = __ AndI(ld, __ ConI(ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
245 assert(ShenandoahBarrierC2Support::is_gc_state_load(ld), "Should match the shape");
246
247 // if (!marking)
248 __ if_then(marking, BoolTest::ne, zero, unlikely); {
249 BasicType index_bt = TypeX_X->basic_type();
250 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading Shenandoah SATBMarkQueue::_index with wrong size.");
251 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
252
253 if (do_load) {
254 // load original value
255 // alias_idx correct??
256 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
257 }
258
259 // if (pre_val != nullptr)
260 __ if_then(pre_val, BoolTest::ne, kit->null()); {
261 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
262
263 // is the queue for this thread full?
264 __ if_then(index, BoolTest::ne, zeroX, likely); {
265
266 // decrement the index
267 Node* next_index = kit->gvn().transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
268
269 // Now get the buffer location we will log the previous value into and store it
270 Node *log_addr = __ AddP(no_base, buffer, next_index);
271 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
272 // update the index
273 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
274
275 } __ else_(); {
276
277 // logging buffer is full, call the runtime
278 const TypeFunc *tf = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type();
279 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), "shenandoah_wb_pre", pre_val, tls);
280 } __ end_if(); // (!index)
281 } __ end_if(); // (pre_val != nullptr)
282 } __ end_if(); // (!marking)
283
284 // Final sync IdealKit and GraphKit.
285 kit->final_sync(ideal);
286
287 if (ShenandoahSATBBarrier && adr != nullptr) {
288 Node* c = kit->control();
289 Node* call = c->in(1)->in(1)->in(1)->in(0);
290 assert(is_shenandoah_wb_pre_call(call), "shenandoah_wb_pre call expected");
291 call->add_req(adr);
292 }
293 }
294
295 bool ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(Node* call) {
296 return call->is_CallLeaf() &&
297 call->as_CallLeaf()->entry_point() == CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry);
298 }
299
300 bool ShenandoahBarrierSetC2::is_shenandoah_lrb_call(Node* call) {
301 if (!call->is_CallLeaf()) {
302 return false;
303 }
304
305 address entry_point = call->as_CallLeaf()->entry_point();
306 return (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong)) ||
307 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow)) ||
308 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak)) ||
309 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow)) ||
310 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom));
311 }
312
313 bool ShenandoahBarrierSetC2::is_shenandoah_marking_if(PhaseTransform *phase, Node* n) {
314 if (n->Opcode() != Op_If) {
315 return false;
316 }
317
318 Node* bol = n->in(1);
319 assert(bol->is_Bool(), "");
320 Node* cmpx = bol->in(1);
321 if (bol->as_Bool()->_test._test == BoolTest::ne &&
322 cmpx->is_Cmp() && cmpx->in(2) == phase->intcon(0) &&
323 is_shenandoah_state_load(cmpx->in(1)->in(1)) &&
324 cmpx->in(1)->in(2)->is_Con() &&
325 cmpx->in(1)->in(2) == phase->intcon(ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING)) {
326 return true;
327 }
328
329 return false;
330 }
331
332 bool ShenandoahBarrierSetC2::is_shenandoah_state_load(Node* n) {
333 if (!n->is_Load()) return false;
334 const int state_offset = in_bytes(ShenandoahThreadLocalData::gc_state_offset());
335 return n->in(2)->is_AddP() && n->in(2)->in(2)->Opcode() == Op_ThreadLocal
336 && n->in(2)->in(3)->is_Con()
337 && n->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == state_offset;
338 }
339
340 void ShenandoahBarrierSetC2::shenandoah_write_barrier_pre(GraphKit* kit,
341 bool do_load,
342 Node* obj,
343 Node* adr,
344 uint alias_idx,
345 Node* val,
346 const TypeOopPtr* val_type,
347 Node* pre_val,
348 BasicType bt) const {
349 if (ShenandoahSATBBarrier) {
350 IdealKit ideal(kit);
351 kit->sync_kit(ideal);
352
353 satb_write_barrier_pre(kit, do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
354
355 ideal.sync_kit(kit);
356 kit->final_sync(ideal);
357 }
358 }
359
360 // Helper that guards and inserts a pre-barrier.
361 void ShenandoahBarrierSetC2::insert_pre_barrier(GraphKit* kit, Node* base_oop, Node* offset,
362 Node* pre_val, bool need_mem_bar) const {
363 // We could be accessing the referent field of a reference object. If so, when Shenandoah
364 // is enabled, we need to log the value in the referent field in an SATB buffer.
365 // This routine performs some compile time filters and generates suitable
366 // runtime filters that guard the pre-barrier code.
367 // Also add memory barrier for non volatile load from the referent field
368 // to prevent commoning of loads across safepoint.
369
370 // Some compile time checks.
371
372 // If offset is a constant, is it java_lang_ref_Reference::_reference_offset?
373 const TypeX* otype = offset->find_intptr_t_type();
374 if (otype != nullptr && otype->is_con() &&
375 otype->get_con() != java_lang_ref_Reference::referent_offset()) {
376 // Constant offset but not the reference_offset so just return
377 return;
378 }
379
380 // We only need to generate the runtime guards for instances.
381 const TypeOopPtr* btype = base_oop->bottom_type()->isa_oopptr();
382 if (btype != nullptr) {
383 if (btype->isa_aryptr()) {
384 // Array type so nothing to do
385 return;
386 }
387
388 const TypeInstPtr* itype = btype->isa_instptr();
389 if (itype != nullptr) {
390 // Can the klass of base_oop be statically determined to be
391 // _not_ a sub-class of Reference and _not_ Object?
392 ciKlass* klass = itype->instance_klass();
393 if (klass->is_loaded() &&
394 !klass->is_subtype_of(kit->env()->Reference_klass()) &&
395 !kit->env()->Object_klass()->is_subtype_of(klass)) {
396 return;
397 }
398 }
399 }
400
401 // The compile time filters did not reject base_oop/offset so
402 // we need to generate the following runtime filters
403 //
404 // if (offset == java_lang_ref_Reference::_reference_offset) {
405 // if (instance_of(base, java.lang.ref.Reference)) {
406 // pre_barrier(_, pre_val, ...);
407 // }
408 // }
409
410 float likely = PROB_LIKELY( 0.999);
411 float unlikely = PROB_UNLIKELY(0.999);
412
413 IdealKit ideal(kit);
414
415 Node* referent_off = __ ConX(java_lang_ref_Reference::referent_offset());
416
417 __ if_then(offset, BoolTest::eq, referent_off, unlikely); {
418 // Update graphKit memory and control from IdealKit.
419 kit->sync_kit(ideal);
420
421 Node* ref_klass_con = kit->makecon(TypeKlassPtr::make(kit->env()->Reference_klass()));
422 Node* is_instof = kit->gen_instanceof(base_oop, ref_klass_con);
423
424 // Update IdealKit memory and control from graphKit.
425 __ sync_kit(kit);
426
427 Node* one = __ ConI(1);
428 // is_instof == 0 if base_oop == nullptr
429 __ if_then(is_instof, BoolTest::eq, one, unlikely); {
430
431 // Update graphKit from IdeakKit.
432 kit->sync_kit(ideal);
433
434 // Use the pre-barrier to record the value in the referent field
435 satb_write_barrier_pre(kit, false /* do_load */,
436 nullptr /* obj */, nullptr /* adr */, max_juint /* alias_idx */, nullptr /* val */, nullptr /* val_type */,
437 pre_val /* pre_val */,
438 T_OBJECT);
439 if (need_mem_bar) {
440 // Add memory barrier to prevent commoning reads from this field
441 // across safepoint since GC can change its value.
442 kit->insert_mem_bar(Op_MemBarCPUOrder);
443 }
444 // Update IdealKit from graphKit.
445 __ sync_kit(kit);
446
447 } __ end_if(); // _ref_type != ref_none
448 } __ end_if(); // offset == referent_offset
449
450 // Final sync IdealKit and GraphKit.
451 kit->final_sync(ideal);
452 }
453
454 Node* ShenandoahBarrierSetC2::byte_map_base_node(GraphKit* kit) const {
455 BarrierSet* bs = BarrierSet::barrier_set();
456 ShenandoahBarrierSet* ctbs = barrier_set_cast<ShenandoahBarrierSet>(bs);
457 CardTable::CardValue* card_table_base = ctbs->card_table()->byte_map_base();
458 if (card_table_base != nullptr) {
459 return kit->makecon(TypeRawPtr::make((address)card_table_base));
460 } else {
461 return kit->null();
462 }
463 }
464
465 void ShenandoahBarrierSetC2::post_barrier(GraphKit* kit,
466 Node* ctl,
467 Node* oop_store,
468 Node* obj,
469 Node* adr,
470 uint adr_idx,
471 Node* val,
472 BasicType bt,
473 bool use_precise) const {
474 if (!ShenandoahHeap::heap()->mode()->is_generational()) {
475 return;
476 }
477
478 ShenandoahBarrierSet* ctbs = barrier_set_cast<ShenandoahBarrierSet>(BarrierSet::barrier_set());
479 CardTable* ct = ctbs->card_table();
480 // No store check needed if we're storing a nullptr or an old object
481 // (latter case is probably a string constant). The concurrent
482 // mark sweep garbage collector, however, needs to have all nonNull
483 // oop updates flagged via card-marks.
484 if (val != nullptr && val->is_Con()) {
485 // must be either an oop or NULL
486 const Type* t = val->bottom_type();
487 if (t == TypePtr::NULL_PTR || t == Type::TOP)
488 // stores of null never (?) need barriers
489 return;
490 }
491
492 if (ReduceInitialCardMarks && obj == kit->just_allocated_object(kit->control())) {
493 // We can skip marks on a freshly-allocated object in Eden.
494 // Keep this code in sync with new_deferred_store_barrier() in runtime.cpp.
495 // That routine informs GC to take appropriate compensating steps,
496 // upon a slow-path allocation, so as to make this card-mark
497 // elision safe.
498 return;
499 }
500
501 if (!use_precise) {
502 // All card marks for a (non-array) instance are in one place:
503 adr = obj;
504 }
505 // (Else it's an array (or unknown), and we want more precise card marks.)
506 assert(adr != nullptr, "");
507
508 IdealKit ideal(kit, true);
509
510 // Convert the pointer to an int prior to doing math on it
511 Node* cast = __ CastPX(__ ctrl(), adr);
512
513 // Divide by card size
514 Node* card_offset = __ URShiftX( cast, __ ConI(CardTable::card_shift()) );
515
516 // Combine card table base and card offset
517 Node* card_adr = __ AddP(__ top(), byte_map_base_node(kit), card_offset );
518
519 // Get the alias_index for raw card-mark memory
520 int adr_type = Compile::AliasIdxRaw;
521 Node* zero = __ ConI(0); // Dirty card value
522
523 if (UseCondCardMark) {
524 // The classic GC reference write barrier is typically implemented
525 // as a store into the global card mark table. Unfortunately
526 // unconditional stores can result in false sharing and excessive
527 // coherence traffic as well as false transactional aborts.
528 // UseCondCardMark enables MP "polite" conditional card mark
529 // stores. In theory we could relax the load from ctrl() to
530 // no_ctrl, but that doesn't buy much latitude.
531 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, T_BYTE, adr_type);
532 __ if_then(card_val, BoolTest::ne, zero);
533 }
534
535 // Smash zero into card
536 __ store(__ ctrl(), card_adr, zero, T_BYTE, adr_type, MemNode::unordered);
537
538 if (UseCondCardMark) {
539 __ end_if();
540 }
541
542 // Final sync IdealKit and GraphKit.
543 kit->final_sync(ideal);
544 }
545
546 #undef __
547
548 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
549 const Type **fields = TypeTuple::fields(2);
550 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
551 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
552 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
553
554 // create result type (range)
555 fields = TypeTuple::fields(0);
556 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
557
558 return TypeFunc::make(domain, range);
559 }
560
561 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
562 const Type **fields = TypeTuple::fields(1);
563 fields[TypeFunc::Parms+0] = TypeOopPtr::NOTNULL; // src oop
564 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
565
566 // create result type (range)
567 fields = TypeTuple::fields(0);
568 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
569
570 return TypeFunc::make(domain, range);
571 }
572
573 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type() {
574 const Type **fields = TypeTuple::fields(2);
575 fields[TypeFunc::Parms+0] = TypeOopPtr::BOTTOM; // original field value
576 fields[TypeFunc::Parms+1] = TypeRawPtr::BOTTOM; // original load address
577
578 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
579
580 // create result type (range)
581 fields = TypeTuple::fields(1);
582 fields[TypeFunc::Parms+0] = TypeOopPtr::BOTTOM;
583 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
584
585 return TypeFunc::make(domain, range);
586 }
587
588 Node* ShenandoahBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
589 DecoratorSet decorators = access.decorators();
590
591 const TypePtr* adr_type = access.addr().type();
592 Node* adr = access.addr().node();
593
594 if (!access.is_oop()) {
595 return BarrierSetC2::store_at_resolved(access, val);
596 }
597
598 if (access.is_parse_access()) {
599 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
600 GraphKit* kit = parse_access.kit();
601
602 uint adr_idx = kit->C->get_alias_index(adr_type);
603 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
604 Node* value = val.node();
605 value = shenandoah_iu_barrier(kit, value);
606 val.set_node(value);
607 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
608 static_cast<const TypeOopPtr*>(val.type()), nullptr /* pre_val */, access.type());
609
610 Node* result = BarrierSetC2::store_at_resolved(access, val);
611
612 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
613 bool is_array = (decorators & IS_ARRAY) != 0;
614 bool use_precise = is_array || anonymous;
615 post_barrier(kit, kit->control(), access.raw_access(), access.base(), adr, adr_idx, val.node(), access.type(), use_precise);
616 return result;
617 } else {
618 assert(access.is_opt_access(), "only for optimization passes");
619 assert(((decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0 || !ShenandoahSATBBarrier) && (decorators & C2_ARRAY_COPY) != 0, "unexpected caller of this code");
620 C2OptAccess& opt_access = static_cast<C2OptAccess&>(access);
621 PhaseGVN& gvn = opt_access.gvn();
622
623 if (ShenandoahIUBarrier) {
624 Node* enqueue = gvn.transform(new ShenandoahIUBarrierNode(val.node()));
625 val.set_node(enqueue);
626 }
627 return BarrierSetC2::store_at_resolved(access, val);
628 }
629 }
630
631 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
632 // 1: non-reference load, no additional barrier is needed
633 if (!access.is_oop()) {
634 return BarrierSetC2::load_at_resolved(access, val_type);;
635 }
636
637 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
638 DecoratorSet decorators = access.decorators();
639 BasicType type = access.type();
640
641 // 2: apply LRB if needed
642 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
643 load = new ShenandoahLoadReferenceBarrierNode(nullptr, load, decorators);
644 if (access.is_parse_access()) {
645 load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
646 } else {
647 load = static_cast<C2OptAccess &>(access).gvn().transform(load);
648 }
649 }
650
651 // 3: apply keep-alive barrier for java.lang.ref.Reference if needed
652 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
653 Node* top = Compile::current()->top();
654 Node* adr = access.addr().node();
655 Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : top;
656 Node* obj = access.base();
657
658 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
659 bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0;
660 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0;
661
662 // If we are reading the value of the referent field of a Reference
663 // object (either by using Unsafe directly or through reflection)
664 // then, if SATB is enabled, we need to record the referent in an
665 // SATB log buffer using the pre-barrier mechanism.
666 // Also we need to add memory barrier to prevent commoning reads
667 // from this field across safepoint since GC can change its value.
668 if (!on_weak_ref || (unknown && (offset == top || obj == top)) || !keep_alive) {
669 return load;
670 }
671
672 assert(access.is_parse_access(), "entry not supported at optimization time");
673 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
674 GraphKit* kit = parse_access.kit();
675 bool mismatched = (decorators & C2_MISMATCHED) != 0;
676 bool is_unordered = (decorators & MO_UNORDERED) != 0;
677 bool in_native = (decorators & IN_NATIVE) != 0;
678 bool need_cpu_mem_bar = !is_unordered || mismatched || in_native;
679
680 if (on_weak_ref) {
681 // Use the pre-barrier to record the value in the referent field
682 satb_write_barrier_pre(kit, false /* do_load */,
683 nullptr /* obj */, nullptr /* adr */, max_juint /* alias_idx */, nullptr /* val */, nullptr /* val_type */,
684 load /* pre_val */, T_OBJECT);
685 // Add memory barrier to prevent commoning reads from this field
686 // across safepoint since GC can change its value.
687 kit->insert_mem_bar(Op_MemBarCPUOrder);
688 } else if (unknown) {
689 // We do not require a mem bar inside pre_barrier if need_mem_bar
690 // is set: the barriers would be emitted by us.
691 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
692 }
693 }
694
695 return load;
696 }
697
698 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
699 Node* new_val, const Type* value_type) const {
700 GraphKit* kit = access.kit();
701 if (access.is_oop()) {
702 new_val = shenandoah_iu_barrier(kit, new_val);
703 shenandoah_write_barrier_pre(kit, false /* do_load */,
704 nullptr, nullptr, max_juint, nullptr, nullptr,
705 expected_val /* pre_val */, T_OBJECT);
706
707 MemNode::MemOrd mo = access.mem_node_mo();
708 Node* mem = access.memory();
709 Node* adr = access.addr().node();
710 const TypePtr* adr_type = access.addr().type();
711 Node* load_store = nullptr;
712
713 #ifdef _LP64
714 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
715 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
716 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
717 if (ShenandoahCASBarrier) {
718 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
719 } else {
720 load_store = kit->gvn().transform(new CompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
721 }
722 } else
723 #endif
724 {
725 if (ShenandoahCASBarrier) {
726 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
727 } else {
728 load_store = kit->gvn().transform(new CompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
729 }
730 }
731
732 access.set_raw_access(load_store);
733 pin_atomic_op(access);
734
735 #ifdef _LP64
736 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
737 load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
738 }
739 #endif
740 load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(nullptr, load_store, access.decorators()));
741 post_barrier(kit, kit->control(), access.raw_access(), access.base(), access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
742 return load_store;
743 }
744 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
745 }
746
747 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
748 Node* new_val, const Type* value_type) const {
749 GraphKit* kit = access.kit();
750 if (access.is_oop()) {
751 new_val = shenandoah_iu_barrier(kit, new_val);
752 shenandoah_write_barrier_pre(kit, false /* do_load */,
753 nullptr, nullptr, max_juint, nullptr, nullptr,
754 expected_val /* pre_val */, T_OBJECT);
755 DecoratorSet decorators = access.decorators();
756 MemNode::MemOrd mo = access.mem_node_mo();
757 Node* mem = access.memory();
758 bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
759 Node* load_store = nullptr;
760 Node* adr = access.addr().node();
761 #ifdef _LP64
762 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
763 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
764 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
765 if (ShenandoahCASBarrier) {
766 if (is_weak_cas) {
767 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
768 } else {
769 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
770 }
771 } else {
772 if (is_weak_cas) {
773 load_store = kit->gvn().transform(new WeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
774 } else {
775 load_store = kit->gvn().transform(new CompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
776 }
777 }
778 } else
779 #endif
780 {
781 if (ShenandoahCASBarrier) {
782 if (is_weak_cas) {
783 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
784 } else {
785 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
786 }
787 } else {
788 if (is_weak_cas) {
789 load_store = kit->gvn().transform(new WeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
790 } else {
791 load_store = kit->gvn().transform(new CompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
792 }
793 }
794 }
795 access.set_raw_access(load_store);
796 pin_atomic_op(access);
797 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
798 access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
799 return load_store;
800 }
801 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
802 }
803
804 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* val, const Type* value_type) const {
805 GraphKit* kit = access.kit();
806 if (access.is_oop()) {
807 val = shenandoah_iu_barrier(kit, val);
808 }
809 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
810 if (access.is_oop()) {
811 result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(nullptr, result, access.decorators()));
812 shenandoah_write_barrier_pre(kit, false /* do_load */,
813 nullptr, nullptr, max_juint, nullptr, nullptr,
814 result /* pre_val */, T_OBJECT);
815 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
816 access.addr().node(), access.alias_idx(), val, T_OBJECT, true);
817 }
818 return result;
819 }
820
821
822 bool ShenandoahBarrierSetC2::is_gc_pre_barrier_node(Node* node) const {
823 return is_shenandoah_wb_pre_call(node);
824 }
825
826 // Support for GC barriers emitted during parsing
827 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
828 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier || node->Opcode() == Op_ShenandoahIUBarrier) return true;
829 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
830 return false;
831 }
832 CallLeafNode *call = node->as_CallLeaf();
833 if (call->_name == nullptr) {
834 return false;
835 }
836
837 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
838 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
839 strcmp(call->_name, "shenandoah_wb_pre") == 0;
840 }
841
842 Node* ShenandoahBarrierSetC2::step_over_gc_barrier(Node* c) const {
843 if (c == nullptr) {
844 return c;
845 }
846 if (c->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
847 return c->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
848 }
849 if (c->Opcode() == Op_ShenandoahIUBarrier) {
850 c = c->in(1);
851 }
852 return c;
853 }
854
855 bool ShenandoahBarrierSetC2::expand_barriers(Compile* C, PhaseIterGVN& igvn) const {
856 return !ShenandoahBarrierC2Support::expand(C, igvn);
857 }
858
859 bool ShenandoahBarrierSetC2::optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const {
860 if (mode == LoopOptsShenandoahExpand) {
861 assert(UseShenandoahGC, "only for shenandoah");
862 ShenandoahBarrierC2Support::pin_and_expand(phase);
863 return true;
864 } else if (mode == LoopOptsShenandoahPostExpand) {
865 assert(UseShenandoahGC, "only for shenandoah");
866 visited.clear();
867 ShenandoahBarrierC2Support::optimize_after_expansion(visited, nstack, worklist, phase);
868 return true;
869 }
870 return false;
871 }
872
873 bool ShenandoahBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, bool is_clone_instance, ArrayCopyPhase phase) const {
874 bool is_oop = is_reference_type(type);
875 if (!is_oop) {
876 return false;
877 }
878 if (ShenandoahSATBBarrier && tightly_coupled_alloc) {
879 if (phase == Optimization) {
880 return false;
881 }
882 return !is_clone;
883 }
884 if (phase == Optimization) {
885 return !ShenandoahIUBarrier;
886 }
887 return true;
888 }
889
890 bool ShenandoahBarrierSetC2::clone_needs_barrier(Node* src, PhaseGVN& gvn) {
891 const TypeOopPtr* src_type = gvn.type(src)->is_oopptr();
892 if (src_type->isa_instptr() != nullptr) {
893 ciInstanceKlass* ik = src_type->is_instptr()->instance_klass();
894 if ((src_type->klass_is_exact() || !ik->has_subklass()) && !ik->has_injected_fields()) {
895 if (ik->has_object_fields()) {
896 return true;
897 } else {
898 if (!src_type->klass_is_exact()) {
899 Compile::current()->dependencies()->assert_leaf_type(ik);
900 }
901 }
902 } else {
903 return true;
904 }
905 } else if (src_type->isa_aryptr()) {
906 BasicType src_elem = src_type->isa_aryptr()->elem()->array_element_basic_type();
907 if (is_reference_type(src_elem, true)) {
908 return true;
909 }
910 } else {
911 return true;
912 }
913 return false;
914 }
915
916 void ShenandoahBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
917 Node* ctrl = ac->in(TypeFunc::Control);
918 Node* mem = ac->in(TypeFunc::Memory);
919 Node* src_base = ac->in(ArrayCopyNode::Src);
920 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
921 Node* dest_base = ac->in(ArrayCopyNode::Dest);
922 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
923 Node* length = ac->in(ArrayCopyNode::Length);
924
925 Node* src = phase->basic_plus_adr(src_base, src_offset);
926 Node* dest = phase->basic_plus_adr(dest_base, dest_offset);
927
928 if (ShenandoahCloneBarrier && clone_needs_barrier(src, phase->igvn())) {
929 // Check if heap is has forwarded objects. If it does, we need to call into the special
930 // routine that would fix up source references before we can continue.
931
932 enum { _heap_stable = 1, _heap_unstable, PATH_LIMIT };
933 Node* region = new RegionNode(PATH_LIMIT);
934 Node* mem_phi = new PhiNode(region, Type::MEMORY, TypeRawPtr::BOTTOM);
935
936 Node* thread = phase->transform_later(new ThreadLocalNode());
937 Node* offset = phase->igvn().MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
938 Node* gc_state_addr = phase->transform_later(new AddPNode(phase->C->top(), thread, offset));
939
940 uint gc_state_idx = Compile::AliasIdxRaw;
941 const TypePtr* gc_state_adr_type = nullptr; // debug-mode-only argument
942 debug_only(gc_state_adr_type = phase->C->get_adr_type(gc_state_idx));
943
944 Node* gc_state = phase->transform_later(new LoadBNode(ctrl, mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered));
945 int flags = ShenandoahHeap::HAS_FORWARDED;
946 if (ShenandoahIUBarrier) {
947 flags |= ShenandoahHeap::YOUNG_MARKING;
948 }
949 Node* stable_and = phase->transform_later(new AndINode(gc_state, phase->igvn().intcon(flags)));
950 Node* stable_cmp = phase->transform_later(new CmpINode(stable_and, phase->igvn().zerocon(T_INT)));
951 Node* stable_test = phase->transform_later(new BoolNode(stable_cmp, BoolTest::ne));
952
953 IfNode* stable_iff = phase->transform_later(new IfNode(ctrl, stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN))->as_If();
954 Node* stable_ctrl = phase->transform_later(new IfFalseNode(stable_iff));
955 Node* unstable_ctrl = phase->transform_later(new IfTrueNode(stable_iff));
956
957 // Heap is stable, no need to do anything additional
958 region->init_req(_heap_stable, stable_ctrl);
959 mem_phi->init_req(_heap_stable, mem);
960
961 // Heap is unstable, call into clone barrier stub
962 Node* call = phase->make_leaf_call(unstable_ctrl, mem,
963 ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type(),
964 CAST_FROM_FN_PTR(address, ShenandoahRuntime::shenandoah_clone_barrier),
965 "shenandoah_clone",
966 TypeRawPtr::BOTTOM,
967 src_base);
968 call = phase->transform_later(call);
969
970 ctrl = phase->transform_later(new ProjNode(call, TypeFunc::Control));
971 mem = phase->transform_later(new ProjNode(call, TypeFunc::Memory));
972 region->init_req(_heap_unstable, ctrl);
973 mem_phi->init_req(_heap_unstable, mem);
974
975 // Wire up the actual arraycopy stub now
976 ctrl = phase->transform_later(region);
977 mem = phase->transform_later(mem_phi);
978
979 const char* name = "arraycopy";
980 call = phase->make_leaf_call(ctrl, mem,
981 OptoRuntime::fast_arraycopy_Type(),
982 phase->basictype2arraycopy(T_LONG, nullptr, nullptr, true, name, true),
983 name, TypeRawPtr::BOTTOM,
984 src, dest, length
985 LP64_ONLY(COMMA phase->top()));
986 call = phase->transform_later(call);
987
988 // Hook up the whole thing into the graph
989 phase->igvn().replace_node(ac, call);
990 } else {
991 BarrierSetC2::clone_at_expansion(phase, ac);
992 }
993 }
994
995
996 // Support for macro expanded GC barriers
997 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
998 if (node->Opcode() == Op_ShenandoahIUBarrier) {
999 state()->add_iu_barrier((ShenandoahIUBarrierNode*) node);
1000 }
1001 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1002 state()->add_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
1003 }
1004 }
1005
1006 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
1007 if (node->Opcode() == Op_ShenandoahIUBarrier) {
1008 state()->remove_iu_barrier((ShenandoahIUBarrierNode*) node);
1009 }
1010 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1011 state()->remove_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
1012 }
1013 }
1014
1015 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const {
1016 if (is_shenandoah_wb_pre_call(node)) {
1017 shenandoah_eliminate_wb_pre(node, ¯o->igvn());
1018 }
1019 if (node->Opcode() == Op_CastP2X && ShenandoahHeap::heap()->mode()->is_generational()) {
1020 assert(node->Opcode() == Op_CastP2X, "ConvP2XNode required");
1021 Node *shift = node->unique_out();
1022 Node *addp = shift->unique_out();
1023 for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) {
1024 Node *mem = addp->last_out(j);
1025 if (UseCondCardMark && mem->is_Load()) {
1026 assert(mem->Opcode() == Op_LoadB, "unexpected code shape");
1027 // The load is checking if the card has been written so
1028 // replace it with zero to fold the test.
1029 macro->replace_node(mem, macro->intcon(0));
1030 continue;
1031 }
1032 assert(mem->is_Store(), "store required");
1033 macro->replace_node(mem, mem->in(MemNode::Memory));
1034 }
1035 }
1036 }
1037
1038 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
1039 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
1040 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
1041 c = c->unique_ctrl_out();
1042 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1043 c = c->unique_ctrl_out();
1044 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1045 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
1046 assert(iff->is_If(), "expect test");
1047 if (!is_shenandoah_marking_if(igvn, iff)) {
1048 c = c->unique_ctrl_out();
1049 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1050 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
1051 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
1052 }
1053 Node* cmpx = iff->in(1)->in(1);
1054 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
1055 igvn->rehash_node_delayed(call);
1056 call->del_req(call->req()-1);
1057 }
1058
1059 void ShenandoahBarrierSetC2::enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {
1060 if (node->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(node)) {
1061 igvn->add_users_to_worklist(node);
1062 }
1063 }
1064
1065 void ShenandoahBarrierSetC2::eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {
1066 for (uint i = 0; i < useful.size(); i++) {
1067 Node* n = useful.at(i);
1068 if (n->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(n)) {
1069 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1070 C->record_for_igvn(n->fast_out(i));
1071 }
1072 }
1073 }
1074 for (int i = state()->iu_barriers_count() - 1; i >= 0; i--) {
1075 ShenandoahIUBarrierNode* n = state()->iu_barrier(i);
1076 if (!useful.member(n)) {
1077 state()->remove_iu_barrier(n);
1078 }
1079 }
1080 for (int i = state()->load_reference_barriers_count() - 1; i >= 0; i--) {
1081 ShenandoahLoadReferenceBarrierNode* n = state()->load_reference_barrier(i);
1082 if (!useful.member(n)) {
1083 state()->remove_load_reference_barrier(n);
1084 }
1085 }
1086 }
1087
1088 void* ShenandoahBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
1089 return new(comp_arena) ShenandoahBarrierSetC2State(comp_arena);
1090 }
1091
1092 ShenandoahBarrierSetC2State* ShenandoahBarrierSetC2::state() const {
1093 return reinterpret_cast<ShenandoahBarrierSetC2State*>(Compile::current()->barrier_set_state());
1094 }
1095
1096 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
1097 // expanded later, then now is the time to do so.
1098 bool ShenandoahBarrierSetC2::expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
1099
1100 #ifdef ASSERT
1101 void ShenandoahBarrierSetC2::verify_gc_barriers(Compile* compile, CompilePhase phase) const {
1102 if (ShenandoahVerifyOptoBarriers && phase == BarrierSetC2::BeforeMacroExpand) {
1103 ShenandoahBarrierC2Support::verify(Compile::current()->root());
1104 } else if (phase == BarrierSetC2::BeforeCodeGen) {
1105 // Verify Shenandoah pre-barriers
1106 const int marking_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset());
1107
1108 Unique_Node_List visited;
1109 Node_List worklist;
1110 // We're going to walk control flow backwards starting from the Root
1111 worklist.push(compile->root());
1112 while (worklist.size() > 0) {
1113 Node *x = worklist.pop();
1114 if (x == nullptr || x == compile->top()) continue;
1115 if (visited.member(x)) {
1116 continue;
1117 } else {
1118 visited.push(x);
1119 }
1120
1121 if (x->is_Region()) {
1122 for (uint i = 1; i < x->req(); i++) {
1123 worklist.push(x->in(i));
1124 }
1125 } else {
1126 worklist.push(x->in(0));
1127 // We are looking for the pattern:
1128 // /->ThreadLocal
1129 // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
1130 // \->ConI(0)
1131 // We want to verify that the If and the LoadB have the same control
1132 // See GraphKit::g1_write_barrier_pre()
1133 if (x->is_If()) {
1134 IfNode *iff = x->as_If();
1135 if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
1136 CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
1137 if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
1138 && cmp->in(1)->is_Load()) {
1139 LoadNode *load = cmp->in(1)->as_Load();
1140 if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
1141 && load->in(2)->in(3)->is_Con()
1142 && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
1143
1144 Node *if_ctrl = iff->in(0);
1145 Node *load_ctrl = load->in(0);
1146
1147 if (if_ctrl != load_ctrl) {
1148 // Skip possible CProj->NeverBranch in infinite loops
1149 if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
1150 && if_ctrl->in(0)->is_NeverBranch()) {
1151 if_ctrl = if_ctrl->in(0)->in(0);
1152 }
1153 }
1154 assert(load_ctrl != nullptr && if_ctrl == load_ctrl, "controls must match");
1155 }
1156 }
1157 }
1158 }
1159 }
1160 }
1161 }
1162 }
1163 #endif
1164
1165 Node* ShenandoahBarrierSetC2::ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const {
1166 if (is_shenandoah_wb_pre_call(n)) {
1167 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1168 if (n->req() > cnt) {
1169 Node* addp = n->in(cnt);
1170 if (has_only_shenandoah_wb_pre_uses(addp)) {
1171 n->del_req(cnt);
1172 if (can_reshape) {
1173 phase->is_IterGVN()->_worklist.push(addp);
1174 }
1175 return n;
1176 }
1177 }
1178 }
1179 if (n->Opcode() == Op_CmpP) {
1180 Node* in1 = n->in(1);
1181 Node* in2 = n->in(2);
1182
1183 // If one input is null, then step over the strong LRB barriers on the other input
1184 if (in1->bottom_type() == TypePtr::NULL_PTR &&
1185 !((in2->Opcode() == Op_ShenandoahLoadReferenceBarrier) &&
1186 !ShenandoahBarrierSet::is_strong_access(((ShenandoahLoadReferenceBarrierNode*)in2)->decorators()))) {
1187 in2 = step_over_gc_barrier(in2);
1188 }
1189 if (in2->bottom_type() == TypePtr::NULL_PTR &&
1190 !((in1->Opcode() == Op_ShenandoahLoadReferenceBarrier) &&
1191 !ShenandoahBarrierSet::is_strong_access(((ShenandoahLoadReferenceBarrierNode*)in1)->decorators()))) {
1192 in1 = step_over_gc_barrier(in1);
1193 }
1194
1195 if (in1 != n->in(1)) {
1196 n->set_req_X(1, in1, phase);
1197 assert(in2 == n->in(2), "only one change");
1198 return n;
1199 }
1200 if (in2 != n->in(2)) {
1201 n->set_req_X(2, in2, phase);
1202 return n;
1203 }
1204 } else if (can_reshape &&
1205 n->Opcode() == Op_If &&
1206 ShenandoahBarrierC2Support::is_heap_stable_test(n) &&
1207 n->in(0) != nullptr &&
1208 n->outcnt() == 2) {
1209 Node* dom = n->in(0);
1210 Node* prev_dom = n;
1211 int op = n->Opcode();
1212 int dist = 16;
1213 // Search up the dominator tree for another heap stable test
1214 while (dom->Opcode() != op || // Not same opcode?
1215 !ShenandoahBarrierC2Support::is_heap_stable_test(dom) || // Not same input 1?
1216 prev_dom->in(0) != dom) { // One path of test does not dominate?
1217 if (dist < 0) return nullptr;
1218
1219 dist--;
1220 prev_dom = dom;
1221 dom = IfNode::up_one_dom(dom);
1222 if (!dom) return nullptr;
1223 }
1224
1225 // Check that we did not follow a loop back to ourselves
1226 if (n == dom) {
1227 return nullptr;
1228 }
1229
1230 return n->as_If()->dominated_by(prev_dom, phase->is_IterGVN());
1231 }
1232
1233 return nullptr;
1234 }
1235
1236 bool ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(Node* n) {
1237 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1238 Node* u = n->fast_out(i);
1239 if (!is_shenandoah_wb_pre_call(u)) {
1240 return false;
1241 }
1242 }
1243 return n->outcnt() > 0;
1244 }
1245
1246 bool ShenandoahBarrierSetC2::final_graph_reshaping(Compile* compile, Node* n, uint opcode, Unique_Node_List& dead_nodes) const {
1247 switch (opcode) {
1248 case Op_CallLeaf:
1249 case Op_CallLeafNoFP: {
1250 assert (n->is_Call(), "");
1251 CallNode *call = n->as_Call();
1252 if (ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(call)) {
1253 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1254 if (call->req() > cnt) {
1255 assert(call->req() == cnt + 1, "only one extra input");
1256 Node *addp = call->in(cnt);
1257 assert(!ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(addp), "useless address computation?");
1258 call->del_req(cnt);
1259 }
1260 }
1261 return false;
1262 }
1263 case Op_ShenandoahCompareAndSwapP:
1264 case Op_ShenandoahCompareAndSwapN:
1265 case Op_ShenandoahWeakCompareAndSwapN:
1266 case Op_ShenandoahWeakCompareAndSwapP:
1267 case Op_ShenandoahCompareAndExchangeP:
1268 case Op_ShenandoahCompareAndExchangeN:
1269 return true;
1270 case Op_ShenandoahLoadReferenceBarrier:
1271 assert(false, "should have been expanded already");
1272 return true;
1273 default:
1274 return false;
1275 }
1276 }
1277
1278 bool ShenandoahBarrierSetC2::escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const {
1279 switch (opcode) {
1280 case Op_ShenandoahCompareAndExchangeP:
1281 case Op_ShenandoahCompareAndExchangeN:
1282 conn_graph->add_objload_to_connection_graph(n, delayed_worklist);
1283 // fallthrough
1284 case Op_ShenandoahWeakCompareAndSwapP:
1285 case Op_ShenandoahWeakCompareAndSwapN:
1286 case Op_ShenandoahCompareAndSwapP:
1287 case Op_ShenandoahCompareAndSwapN:
1288 conn_graph->add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1289 return true;
1290 case Op_StoreP: {
1291 Node* adr = n->in(MemNode::Address);
1292 const Type* adr_type = gvn->type(adr);
1293 // Pointer stores in Shenandoah barriers looks like unsafe access.
1294 // Ignore such stores to be able scalar replace non-escaping
1295 // allocations.
1296 if (adr_type->isa_rawptr() && adr->is_AddP()) {
1297 Node* base = conn_graph->get_addp_base(adr);
1298 if (base->Opcode() == Op_LoadP &&
1299 base->in(MemNode::Address)->is_AddP()) {
1300 adr = base->in(MemNode::Address);
1301 Node* tls = conn_graph->get_addp_base(adr);
1302 if (tls->Opcode() == Op_ThreadLocal) {
1303 int offs = (int) gvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1304 const int buf_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
1305 if (offs == buf_offset) {
1306 return true; // Pre barrier previous oop value store.
1307 }
1308 }
1309 }
1310 }
1311 return false;
1312 }
1313 case Op_ShenandoahIUBarrier:
1314 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1315 break;
1316 case Op_ShenandoahLoadReferenceBarrier:
1317 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), delayed_worklist);
1318 return true;
1319 default:
1320 // Nothing
1321 break;
1322 }
1323 return false;
1324 }
1325
1326 bool ShenandoahBarrierSetC2::escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const {
1327 switch (opcode) {
1328 case Op_ShenandoahCompareAndExchangeP:
1329 case Op_ShenandoahCompareAndExchangeN: {
1330 Node *adr = n->in(MemNode::Address);
1331 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, adr, nullptr);
1332 // fallthrough
1333 }
1334 case Op_ShenandoahCompareAndSwapP:
1335 case Op_ShenandoahCompareAndSwapN:
1336 case Op_ShenandoahWeakCompareAndSwapP:
1337 case Op_ShenandoahWeakCompareAndSwapN:
1338 return conn_graph->add_final_edges_unsafe_access(n, opcode);
1339 case Op_ShenandoahIUBarrier:
1340 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), nullptr);
1341 return true;
1342 case Op_ShenandoahLoadReferenceBarrier:
1343 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), nullptr);
1344 return true;
1345 default:
1346 // Nothing
1347 break;
1348 }
1349 return false;
1350 }
1351
1352 bool ShenandoahBarrierSetC2::escape_has_out_with_unsafe_object(Node* n) const {
1353 return n->has_out_with(Op_ShenandoahCompareAndExchangeP) || n->has_out_with(Op_ShenandoahCompareAndExchangeN) ||
1354 n->has_out_with(Op_ShenandoahCompareAndSwapP, Op_ShenandoahCompareAndSwapN, Op_ShenandoahWeakCompareAndSwapP, Op_ShenandoahWeakCompareAndSwapN);
1355
1356 }
1357
1358 bool ShenandoahBarrierSetC2::matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const {
1359 switch (opcode) {
1360 case Op_ShenandoahCompareAndExchangeP:
1361 case Op_ShenandoahCompareAndExchangeN:
1362 case Op_ShenandoahWeakCompareAndSwapP:
1363 case Op_ShenandoahWeakCompareAndSwapN:
1364 case Op_ShenandoahCompareAndSwapP:
1365 case Op_ShenandoahCompareAndSwapN: { // Convert trinary to binary-tree
1366 Node* newval = n->in(MemNode::ValueIn);
1367 Node* oldval = n->in(LoadStoreConditionalNode::ExpectedIn);
1368 Node* pair = new BinaryNode(oldval, newval);
1369 n->set_req(MemNode::ValueIn,pair);
1370 n->del_req(LoadStoreConditionalNode::ExpectedIn);
1371 return true;
1372 }
1373 default:
1374 break;
1375 }
1376 return false;
1377 }
1378
1379 bool ShenandoahBarrierSetC2::matcher_is_store_load_barrier(Node* x, uint xop) const {
1380 return xop == Op_ShenandoahCompareAndExchangeP ||
1381 xop == Op_ShenandoahCompareAndExchangeN ||
1382 xop == Op_ShenandoahWeakCompareAndSwapP ||
1383 xop == Op_ShenandoahWeakCompareAndSwapN ||
1384 xop == Op_ShenandoahCompareAndSwapN ||
1385 xop == Op_ShenandoahCompareAndSwapP;
1386 }