1 /*
2 * Copyright (c) 2018, 2023, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "gc/shared/barrierSet.hpp"
29 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
30 #include "gc/shenandoah/shenandoahForwarding.hpp"
31 #include "gc/shenandoah/shenandoahHeap.hpp"
32 #include "gc/shenandoah/shenandoahRuntime.hpp"
33 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
34 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
35 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
36 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
37 #include "gc/shenandoah/mode/shenandoahMode.hpp"
38 #include "opto/arraycopynode.hpp"
39 #include "opto/escape.hpp"
40 #include "opto/graphKit.hpp"
41 #include "opto/idealKit.hpp"
42 #include "opto/macro.hpp"
43 #include "opto/movenode.hpp"
44 #include "opto/narrowptrnode.hpp"
45 #include "opto/rootnode.hpp"
46 #include "opto/runtime.hpp"
47
48 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
49 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
50 }
51
52 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
53 : _iu_barriers(new (comp_arena) GrowableArray<ShenandoahIUBarrierNode*>(comp_arena, 8, 0, nullptr)),
54 _load_reference_barriers(new (comp_arena) GrowableArray<ShenandoahLoadReferenceBarrierNode*>(comp_arena, 8, 0, nullptr)) {
55 }
56
57 int ShenandoahBarrierSetC2State::iu_barriers_count() const {
58 return _iu_barriers->length();
59 }
60
61 ShenandoahIUBarrierNode* ShenandoahBarrierSetC2State::iu_barrier(int idx) const {
62 return _iu_barriers->at(idx);
63 }
64
65 void ShenandoahBarrierSetC2State::add_iu_barrier(ShenandoahIUBarrierNode* n) {
66 assert(!_iu_barriers->contains(n), "duplicate entry in barrier list");
67 _iu_barriers->append(n);
68 }
69
70 void ShenandoahBarrierSetC2State::remove_iu_barrier(ShenandoahIUBarrierNode* n) {
71 _iu_barriers->remove_if_existing(n);
72 }
73
74 int ShenandoahBarrierSetC2State::load_reference_barriers_count() const {
75 return _load_reference_barriers->length();
76 }
77
78 ShenandoahLoadReferenceBarrierNode* ShenandoahBarrierSetC2State::load_reference_barrier(int idx) const {
79 return _load_reference_barriers->at(idx);
80 }
81
82 void ShenandoahBarrierSetC2State::add_load_reference_barrier(ShenandoahLoadReferenceBarrierNode * n) {
83 assert(!_load_reference_barriers->contains(n), "duplicate entry in barrier list");
84 _load_reference_barriers->append(n);
85 }
86
87 void ShenandoahBarrierSetC2State::remove_load_reference_barrier(ShenandoahLoadReferenceBarrierNode * n) {
88 if (_load_reference_barriers->contains(n)) {
89 _load_reference_barriers->remove(n);
90 }
91 }
92
93 Node* ShenandoahBarrierSetC2::shenandoah_iu_barrier(GraphKit* kit, Node* obj) const {
94 if (ShenandoahIUBarrier) {
95 return kit->gvn().transform(new ShenandoahIUBarrierNode(obj));
96 }
97 return obj;
98 }
99
100 #define __ kit->
101
102 bool ShenandoahBarrierSetC2::satb_can_remove_pre_barrier(GraphKit* kit, PhaseValues* phase, Node* adr,
103 BasicType bt, uint adr_idx) const {
104 intptr_t offset = 0;
105 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
106 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
107
108 if (offset == Type::OffsetBot) {
109 return false; // cannot unalias unless there are precise offsets
110 }
111
112 if (alloc == nullptr) {
113 return false; // No allocation found
114 }
115
116 intptr_t size_in_bytes = type2aelembytes(bt);
117
118 Node* mem = __ memory(adr_idx); // start searching here...
119
120 for (int cnt = 0; cnt < 50; cnt++) {
121
122 if (mem->is_Store()) {
123
124 Node* st_adr = mem->in(MemNode::Address);
125 intptr_t st_offset = 0;
126 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
127
128 if (st_base == nullptr) {
129 break; // inscrutable pointer
130 }
131
132 // Break we have found a store with same base and offset as ours so break
133 if (st_base == base && st_offset == offset) {
134 break;
135 }
136
137 if (st_offset != offset && st_offset != Type::OffsetBot) {
138 const int MAX_STORE = BytesPerLong;
139 if (st_offset >= offset + size_in_bytes ||
140 st_offset <= offset - MAX_STORE ||
141 st_offset <= offset - mem->as_Store()->memory_size()) {
142 // Success: The offsets are provably independent.
143 // (You may ask, why not just test st_offset != offset and be done?
144 // The answer is that stores of different sizes can co-exist
145 // in the same sequence of RawMem effects. We sometimes initialize
146 // a whole 'tile' of array elements with a single jint or jlong.)
147 mem = mem->in(MemNode::Memory);
148 continue; // advance through independent store memory
149 }
150 }
151
152 if (st_base != base
153 && MemNode::detect_ptr_independence(base, alloc, st_base,
154 AllocateNode::Ideal_allocation(st_base, phase),
155 phase)) {
156 // Success: The bases are provably independent.
157 mem = mem->in(MemNode::Memory);
158 continue; // advance through independent store memory
159 }
160 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
161
162 InitializeNode* st_init = mem->in(0)->as_Initialize();
163 AllocateNode* st_alloc = st_init->allocation();
164
165 // Make sure that we are looking at the same allocation site.
166 // The alloc variable is guaranteed to not be null here from earlier check.
167 if (alloc == st_alloc) {
168 // Check that the initialization is storing null so that no previous store
169 // has been moved up and directly write a reference
170 Node* captured_store = st_init->find_captured_store(offset,
171 type2aelembytes(T_OBJECT),
172 phase);
173 if (captured_store == nullptr || captured_store == st_init->zero_memory()) {
174 return true;
175 }
176 }
177 }
178
179 // Unless there is an explicit 'continue', we must bail out here,
180 // because 'mem' is an inscrutable memory state (e.g., a call).
181 break;
182 }
183
184 return false;
185 }
186
187 #undef __
188 #define __ ideal.
189
190 void ShenandoahBarrierSetC2::satb_write_barrier_pre(GraphKit* kit,
191 bool do_load,
192 Node* obj,
193 Node* adr,
194 uint alias_idx,
195 Node* val,
196 const TypeOopPtr* val_type,
197 Node* pre_val,
198 BasicType bt) const {
199 // Some sanity checks
200 // Note: val is unused in this routine.
201
202 if (do_load) {
203 // We need to generate the load of the previous value
204 assert(adr != nullptr, "where are loading from?");
205 assert(pre_val == nullptr, "loaded already?");
206 assert(val_type != nullptr, "need a type");
207
208 if (ReduceInitialCardMarks
209 && satb_can_remove_pre_barrier(kit, &kit->gvn(), adr, bt, alias_idx)) {
210 return;
211 }
212
213 } else {
214 // In this case both val_type and alias_idx are unused.
215 assert(pre_val != nullptr, "must be loaded already");
216 // Nothing to be done if pre_val is null.
217 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
218 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
219 }
220 assert(bt == T_OBJECT, "or we shouldn't be here");
221
222 IdealKit ideal(kit, true);
223
224 Node* tls = __ thread(); // ThreadLocalStorage
225
226 Node* no_base = __ top();
227 Node* zero = __ ConI(0);
228 Node* zeroX = __ ConX(0);
229
230 float likely = PROB_LIKELY(0.999);
231 float unlikely = PROB_UNLIKELY(0.999);
232
233 // Offsets into the thread
234 const int index_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset());
235 const int buffer_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
236
237 // Now the actual pointers into the thread
238 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
239 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
240
241 // Now some of the values
242 Node* marking;
243 Node* gc_state = __ AddP(no_base, tls, __ ConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset())));
244 Node* ld = __ load(__ ctrl(), gc_state, TypeInt::BYTE, T_BYTE, Compile::AliasIdxRaw);
245 marking = __ AndI(ld, __ ConI(ShenandoahHeap::MARKING));
246 assert(ShenandoahBarrierC2Support::is_gc_state_load(ld), "Should match the shape");
247
248 // if (!marking)
249 __ if_then(marking, BoolTest::ne, zero, unlikely); {
250 BasicType index_bt = TypeX_X->basic_type();
251 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading Shenandoah SATBMarkQueue::_index with wrong size.");
252 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
253
254 if (do_load) {
255 // load original value
256 // alias_idx correct??
257 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
258 }
259
260 // if (pre_val != nullptr)
261 __ if_then(pre_val, BoolTest::ne, kit->null()); {
262 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
263
264 // is the queue for this thread full?
265 __ if_then(index, BoolTest::ne, zeroX, likely); {
266
267 // decrement the index
268 Node* next_index = kit->gvn().transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
269
270 // Now get the buffer location we will log the previous value into and store it
271 Node *log_addr = __ AddP(no_base, buffer, next_index);
272 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
273 // update the index
274 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
275
276 } __ else_(); {
277
278 // logging buffer is full, call the runtime
279 const TypeFunc *tf = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type();
280 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), "shenandoah_wb_pre", pre_val, tls);
281 } __ end_if(); // (!index)
282 } __ end_if(); // (pre_val != nullptr)
283 } __ end_if(); // (!marking)
284
285 // Final sync IdealKit and GraphKit.
286 kit->final_sync(ideal);
287
288 if (ShenandoahSATBBarrier && adr != nullptr) {
289 Node* c = kit->control();
290 Node* call = c->in(1)->in(1)->in(1)->in(0);
291 assert(is_shenandoah_wb_pre_call(call), "shenandoah_wb_pre call expected");
292 call->add_req(adr);
293 }
294 }
295
296 bool ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(Node* call) {
297 return call->is_CallLeaf() &&
298 call->as_CallLeaf()->entry_point() == CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry);
299 }
300
301 bool ShenandoahBarrierSetC2::is_shenandoah_lrb_call(Node* call) {
302 if (!call->is_CallLeaf()) {
303 return false;
304 }
305
306 address entry_point = call->as_CallLeaf()->entry_point();
307 return (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong)) ||
308 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow)) ||
309 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak)) ||
310 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow)) ||
311 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom));
312 }
313
314 bool ShenandoahBarrierSetC2::is_shenandoah_marking_if(PhaseValues* phase, Node* n) {
315 if (n->Opcode() != Op_If) {
316 return false;
317 }
318
319 Node* bol = n->in(1);
320 assert(bol->is_Bool(), "");
321 Node* cmpx = bol->in(1);
322 if (bol->as_Bool()->_test._test == BoolTest::ne &&
323 cmpx->is_Cmp() && cmpx->in(2) == phase->intcon(0) &&
324 is_shenandoah_state_load(cmpx->in(1)->in(1)) &&
325 cmpx->in(1)->in(2)->is_Con() &&
326 cmpx->in(1)->in(2) == phase->intcon(ShenandoahHeap::MARKING)) {
327 return true;
328 }
329
330 return false;
331 }
332
333 bool ShenandoahBarrierSetC2::is_shenandoah_state_load(Node* n) {
334 if (!n->is_Load()) return false;
335 const int state_offset = in_bytes(ShenandoahThreadLocalData::gc_state_offset());
336 return n->in(2)->is_AddP() && n->in(2)->in(2)->Opcode() == Op_ThreadLocal
337 && n->in(2)->in(3)->is_Con()
338 && n->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == state_offset;
339 }
340
341 void ShenandoahBarrierSetC2::shenandoah_write_barrier_pre(GraphKit* kit,
342 bool do_load,
343 Node* obj,
344 Node* adr,
345 uint alias_idx,
346 Node* val,
347 const TypeOopPtr* val_type,
348 Node* pre_val,
349 BasicType bt) const {
350 if (ShenandoahSATBBarrier) {
351 IdealKit ideal(kit);
352 kit->sync_kit(ideal);
353
354 satb_write_barrier_pre(kit, do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
355
356 ideal.sync_kit(kit);
357 kit->final_sync(ideal);
358 }
359 }
360
361 // Helper that guards and inserts a pre-barrier.
362 void ShenandoahBarrierSetC2::insert_pre_barrier(GraphKit* kit, Node* base_oop, Node* offset,
363 Node* pre_val, bool need_mem_bar) const {
364 // We could be accessing the referent field of a reference object. If so, when Shenandoah
365 // is enabled, we need to log the value in the referent field in an SATB buffer.
366 // This routine performs some compile time filters and generates suitable
367 // runtime filters that guard the pre-barrier code.
368 // Also add memory barrier for non volatile load from the referent field
369 // to prevent commoning of loads across safepoint.
370
371 // Some compile time checks.
372
373 // If offset is a constant, is it java_lang_ref_Reference::_reference_offset?
374 const TypeX* otype = offset->find_intptr_t_type();
375 if (otype != nullptr && otype->is_con() &&
376 otype->get_con() != java_lang_ref_Reference::referent_offset()) {
377 // Constant offset but not the reference_offset so just return
378 return;
379 }
380
381 // We only need to generate the runtime guards for instances.
382 const TypeOopPtr* btype = base_oop->bottom_type()->isa_oopptr();
383 if (btype != nullptr) {
384 if (btype->isa_aryptr()) {
385 // Array type so nothing to do
386 return;
387 }
388
389 const TypeInstPtr* itype = btype->isa_instptr();
390 if (itype != nullptr) {
391 // Can the klass of base_oop be statically determined to be
392 // _not_ a sub-class of Reference and _not_ Object?
393 ciKlass* klass = itype->instance_klass();
394 if (klass->is_loaded() &&
395 !klass->is_subtype_of(kit->env()->Reference_klass()) &&
396 !kit->env()->Object_klass()->is_subtype_of(klass)) {
397 return;
398 }
399 }
400 }
401
402 // The compile time filters did not reject base_oop/offset so
403 // we need to generate the following runtime filters
404 //
405 // if (offset == java_lang_ref_Reference::_reference_offset) {
406 // if (instance_of(base, java.lang.ref.Reference)) {
407 // pre_barrier(_, pre_val, ...);
408 // }
409 // }
410
411 float likely = PROB_LIKELY( 0.999);
412 float unlikely = PROB_UNLIKELY(0.999);
413
414 IdealKit ideal(kit);
415
416 Node* referent_off = __ ConX(java_lang_ref_Reference::referent_offset());
417
418 __ if_then(offset, BoolTest::eq, referent_off, unlikely); {
419 // Update graphKit memory and control from IdealKit.
420 kit->sync_kit(ideal);
421
422 Node* ref_klass_con = kit->makecon(TypeKlassPtr::make(kit->env()->Reference_klass()));
423 Node* is_instof = kit->gen_instanceof(base_oop, ref_klass_con);
424
425 // Update IdealKit memory and control from graphKit.
426 __ sync_kit(kit);
427
428 Node* one = __ ConI(1);
429 // is_instof == 0 if base_oop == nullptr
430 __ if_then(is_instof, BoolTest::eq, one, unlikely); {
431
432 // Update graphKit from IdeakKit.
433 kit->sync_kit(ideal);
434
435 // Use the pre-barrier to record the value in the referent field
436 satb_write_barrier_pre(kit, false /* do_load */,
437 nullptr /* obj */, nullptr /* adr */, max_juint /* alias_idx */, nullptr /* val */, nullptr /* val_type */,
438 pre_val /* pre_val */,
439 T_OBJECT);
440 if (need_mem_bar) {
441 // Add memory barrier to prevent commoning reads from this field
442 // across safepoint since GC can change its value.
443 kit->insert_mem_bar(Op_MemBarCPUOrder);
444 }
445 // Update IdealKit from graphKit.
446 __ sync_kit(kit);
447
448 } __ end_if(); // _ref_type != ref_none
449 } __ end_if(); // offset == referent_offset
450
451 // Final sync IdealKit and GraphKit.
452 kit->final_sync(ideal);
453 }
454
455 Node* ShenandoahBarrierSetC2::byte_map_base_node(GraphKit* kit) const {
456 BarrierSet* bs = BarrierSet::barrier_set();
457 ShenandoahBarrierSet* ctbs = barrier_set_cast<ShenandoahBarrierSet>(bs);
458 CardTable::CardValue* card_table_base = ctbs->card_table()->byte_map_base();
459 if (card_table_base != nullptr) {
460 return kit->makecon(TypeRawPtr::make((address)card_table_base));
461 } else {
462 return kit->null();
463 }
464 }
465
466 void ShenandoahBarrierSetC2::post_barrier(GraphKit* kit,
467 Node* ctl,
468 Node* oop_store,
469 Node* obj,
470 Node* adr,
471 uint adr_idx,
472 Node* val,
473 BasicType bt,
474 bool use_precise) const {
475 assert(ShenandoahCardBarrier, "Did you mean to enable ShenandoahCardBarrier?");
476
477 // No store check needed if we're storing a null.
478 if (val != nullptr && val->is_Con()) {
479 // must be either an oop or NULL
480 const Type* t = val->bottom_type();
481 if (t == TypePtr::NULL_PTR || t == Type::TOP)
482 return;
483 }
484
485 if (ReduceInitialCardMarks && obj == kit->just_allocated_object(kit->control())) {
486 // We can skip marks on a freshly-allocated object in Eden.
487 // Keep this code in sync with new_deferred_store_barrier() in runtime.cpp.
488 // That routine informs GC to take appropriate compensating steps,
489 // upon a slow-path allocation, so as to make this card-mark
490 // elision safe.
491 return;
492 }
493
494 if (!use_precise) {
495 // All card marks for a (non-array) instance are in one place:
496 adr = obj;
497 }
498 // (Else it's an array (or unknown), and we want more precise card marks.)
499 assert(adr != nullptr, "");
500
501 IdealKit ideal(kit, true);
502
503 // Convert the pointer to an int prior to doing math on it
504 Node* cast = __ CastPX(__ ctrl(), adr);
505
506 // Divide by card size
507 Node* card_offset = __ URShiftX( cast, __ ConI(CardTable::card_shift()) );
508
509 // Combine card table base and card offset
510 Node* card_adr = __ AddP(__ top(), byte_map_base_node(kit), card_offset );
511
512 // Get the alias_index for raw card-mark memory
513 int adr_type = Compile::AliasIdxRaw;
514 Node* zero = __ ConI(0); // Dirty card value
515
516 if (UseCondCardMark) {
517 // The classic GC reference write barrier is typically implemented
518 // as a store into the global card mark table. Unfortunately
519 // unconditional stores can result in false sharing and excessive
520 // coherence traffic as well as false transactional aborts.
521 // UseCondCardMark enables MP "polite" conditional card mark
522 // stores. In theory we could relax the load from ctrl() to
523 // no_ctrl, but that doesn't buy much latitude.
524 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, T_BYTE, adr_type);
525 __ if_then(card_val, BoolTest::ne, zero);
526 }
527
528 // Smash zero into card
529 __ store(__ ctrl(), card_adr, zero, T_BYTE, adr_type, MemNode::unordered);
530
531 if (UseCondCardMark) {
532 __ end_if();
533 }
534
535 // Final sync IdealKit and GraphKit.
536 kit->final_sync(ideal);
537 }
538
539 #undef __
540
541 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
542 const Type **fields = TypeTuple::fields(2);
543 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
544 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
545 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
546
547 // create result type (range)
548 fields = TypeTuple::fields(0);
549 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
550
551 return TypeFunc::make(domain, range);
552 }
553
554 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
555 const Type **fields = TypeTuple::fields(1);
556 fields[TypeFunc::Parms+0] = TypeOopPtr::NOTNULL; // src oop
557 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
558
559 // create result type (range)
560 fields = TypeTuple::fields(0);
561 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
562
563 return TypeFunc::make(domain, range);
564 }
565
566 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type() {
567 const Type **fields = TypeTuple::fields(2);
568 fields[TypeFunc::Parms+0] = TypeOopPtr::BOTTOM; // original field value
569 fields[TypeFunc::Parms+1] = TypeRawPtr::BOTTOM; // original load address
570
571 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
572
573 // create result type (range)
574 fields = TypeTuple::fields(1);
575 fields[TypeFunc::Parms+0] = TypeOopPtr::BOTTOM;
576 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
577
578 return TypeFunc::make(domain, range);
579 }
580
581 Node* ShenandoahBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
582 DecoratorSet decorators = access.decorators();
583
584 const TypePtr* adr_type = access.addr().type();
585 Node* adr = access.addr().node();
586
587 if (!access.is_oop()) {
588 return BarrierSetC2::store_at_resolved(access, val);
589 }
590
591 if (access.is_parse_access()) {
592 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
593 GraphKit* kit = parse_access.kit();
594
595 uint adr_idx = kit->C->get_alias_index(adr_type);
596 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
597 Node* value = val.node();
598 value = shenandoah_iu_barrier(kit, value);
599 val.set_node(value);
600 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
601 static_cast<const TypeOopPtr*>(val.type()), nullptr /* pre_val */, access.type());
602
603 Node* result = BarrierSetC2::store_at_resolved(access, val);
604
605 if (ShenandoahCardBarrier) {
606 const bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
607 const bool is_array = (decorators & IS_ARRAY) != 0;
608 const bool use_precise = is_array || anonymous;
609 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
610 adr, adr_idx, val.node(), access.type(), use_precise);
611 }
612 return result;
613 } else {
614 assert(access.is_opt_access(), "only for optimization passes");
615 assert(((decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0 || !ShenandoahSATBBarrier) && (decorators & C2_ARRAY_COPY) != 0, "unexpected caller of this code");
616 C2OptAccess& opt_access = static_cast<C2OptAccess&>(access);
617 PhaseGVN& gvn = opt_access.gvn();
618
619 if (ShenandoahIUBarrier) {
620 Node* enqueue = gvn.transform(new ShenandoahIUBarrierNode(val.node()));
621 val.set_node(enqueue);
622 }
623 return BarrierSetC2::store_at_resolved(access, val);
624 }
625 }
626
627 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
628 // 1: non-reference load, no additional barrier is needed
629 if (!access.is_oop()) {
630 return BarrierSetC2::load_at_resolved(access, val_type);
631 }
632
633 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
634 DecoratorSet decorators = access.decorators();
635 BasicType type = access.type();
636
637 // 2: apply LRB if needed
638 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
639 load = new ShenandoahLoadReferenceBarrierNode(nullptr, load, decorators);
640 if (access.is_parse_access()) {
641 load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
642 } else {
643 load = static_cast<C2OptAccess &>(access).gvn().transform(load);
644 }
645 }
646
647 // 3: apply keep-alive barrier for java.lang.ref.Reference if needed
648 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
649 Node* top = Compile::current()->top();
650 Node* adr = access.addr().node();
651 Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : top;
652 Node* obj = access.base();
653
654 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
655 bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0;
656 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0;
657
658 // If we are reading the value of the referent field of a Reference
659 // object (either by using Unsafe directly or through reflection)
660 // then, if SATB is enabled, we need to record the referent in an
661 // SATB log buffer using the pre-barrier mechanism.
662 // Also we need to add memory barrier to prevent commoning reads
663 // from this field across safepoint since GC can change its value.
664 if (!on_weak_ref || (unknown && (offset == top || obj == top)) || !keep_alive) {
665 return load;
666 }
667
668 assert(access.is_parse_access(), "entry not supported at optimization time");
669 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
670 GraphKit* kit = parse_access.kit();
671 bool mismatched = (decorators & C2_MISMATCHED) != 0;
672 bool is_unordered = (decorators & MO_UNORDERED) != 0;
673 bool in_native = (decorators & IN_NATIVE) != 0;
674 bool need_cpu_mem_bar = !is_unordered || mismatched || in_native;
675
676 if (on_weak_ref) {
677 // Use the pre-barrier to record the value in the referent field
678 satb_write_barrier_pre(kit, false /* do_load */,
679 nullptr /* obj */, nullptr /* adr */, max_juint /* alias_idx */, nullptr /* val */, nullptr /* val_type */,
680 load /* pre_val */, T_OBJECT);
681 // Add memory barrier to prevent commoning reads from this field
682 // across safepoint since GC can change its value.
683 kit->insert_mem_bar(Op_MemBarCPUOrder);
684 } else if (unknown) {
685 // We do not require a mem bar inside pre_barrier if need_mem_bar
686 // is set: the barriers would be emitted by us.
687 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
688 }
689 }
690
691 return load;
692 }
693
694 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
695 Node* new_val, const Type* value_type) const {
696 GraphKit* kit = access.kit();
697 if (access.is_oop()) {
698 new_val = shenandoah_iu_barrier(kit, new_val);
699 shenandoah_write_barrier_pre(kit, false /* do_load */,
700 nullptr, nullptr, max_juint, nullptr, nullptr,
701 expected_val /* pre_val */, T_OBJECT);
702
703 MemNode::MemOrd mo = access.mem_node_mo();
704 Node* mem = access.memory();
705 Node* adr = access.addr().node();
706 const TypePtr* adr_type = access.addr().type();
707 Node* load_store = nullptr;
708
709 #ifdef _LP64
710 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
711 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
712 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
713 if (ShenandoahCASBarrier) {
714 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
715 } else {
716 load_store = kit->gvn().transform(new CompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
717 }
718 } else
719 #endif
720 {
721 if (ShenandoahCASBarrier) {
722 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
723 } else {
724 load_store = kit->gvn().transform(new CompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
725 }
726 }
727
728 access.set_raw_access(load_store);
729 pin_atomic_op(access);
730
731 #ifdef _LP64
732 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
733 load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
734 }
735 #endif
736 load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(nullptr, load_store, access.decorators()));
737 if (ShenandoahCardBarrier) {
738 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
739 access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
740 }
741 return load_store;
742 }
743 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
744 }
745
746 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
747 Node* new_val, const Type* value_type) const {
748 GraphKit* kit = access.kit();
749 if (access.is_oop()) {
750 new_val = shenandoah_iu_barrier(kit, new_val);
751 shenandoah_write_barrier_pre(kit, false /* do_load */,
752 nullptr, nullptr, max_juint, nullptr, nullptr,
753 expected_val /* pre_val */, T_OBJECT);
754 DecoratorSet decorators = access.decorators();
755 MemNode::MemOrd mo = access.mem_node_mo();
756 Node* mem = access.memory();
757 bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
758 Node* load_store = nullptr;
759 Node* adr = access.addr().node();
760 #ifdef _LP64
761 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
762 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
763 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
764 if (ShenandoahCASBarrier) {
765 if (is_weak_cas) {
766 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
767 } else {
768 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
769 }
770 } else {
771 if (is_weak_cas) {
772 load_store = kit->gvn().transform(new WeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
773 } else {
774 load_store = kit->gvn().transform(new CompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
775 }
776 }
777 } else
778 #endif
779 {
780 if (ShenandoahCASBarrier) {
781 if (is_weak_cas) {
782 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
783 } else {
784 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
785 }
786 } else {
787 if (is_weak_cas) {
788 load_store = kit->gvn().transform(new WeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
789 } else {
790 load_store = kit->gvn().transform(new CompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
791 }
792 }
793 }
794 access.set_raw_access(load_store);
795 pin_atomic_op(access);
796 if (ShenandoahCardBarrier) {
797 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
798 access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
799 }
800 return load_store;
801 }
802 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
803 }
804
805 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* val, const Type* value_type) const {
806 GraphKit* kit = access.kit();
807 if (access.is_oop()) {
808 val = shenandoah_iu_barrier(kit, val);
809 }
810 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
811 if (access.is_oop()) {
812 result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(nullptr, result, access.decorators()));
813 shenandoah_write_barrier_pre(kit, false /* do_load */,
814 nullptr, nullptr, max_juint, nullptr, nullptr,
815 result /* pre_val */, T_OBJECT);
816 if (ShenandoahCardBarrier) {
817 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
818 access.addr().node(), access.alias_idx(), val, T_OBJECT, true);
819 }
820 }
821 return result;
822 }
823
824
825 bool ShenandoahBarrierSetC2::is_gc_pre_barrier_node(Node* node) const {
826 return is_shenandoah_wb_pre_call(node);
827 }
828
829 // Support for GC barriers emitted during parsing
830 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
831 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier || node->Opcode() == Op_ShenandoahIUBarrier) return true;
832 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
833 return false;
834 }
835 CallLeafNode *call = node->as_CallLeaf();
836 if (call->_name == nullptr) {
837 return false;
838 }
839
840 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
841 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
842 strcmp(call->_name, "shenandoah_wb_pre") == 0;
843 }
844
845 Node* ShenandoahBarrierSetC2::step_over_gc_barrier(Node* c) const {
846 if (c == nullptr) {
847 return c;
848 }
849 if (c->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
850 return c->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
851 }
852 if (c->Opcode() == Op_ShenandoahIUBarrier) {
853 c = c->in(1);
854 }
855 return c;
856 }
857
858 bool ShenandoahBarrierSetC2::expand_barriers(Compile* C, PhaseIterGVN& igvn) const {
859 return !ShenandoahBarrierC2Support::expand(C, igvn);
860 }
861
862 bool ShenandoahBarrierSetC2::optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const {
863 if (mode == LoopOptsShenandoahExpand) {
864 assert(UseShenandoahGC, "only for shenandoah");
865 ShenandoahBarrierC2Support::pin_and_expand(phase);
866 return true;
867 } else if (mode == LoopOptsShenandoahPostExpand) {
868 assert(UseShenandoahGC, "only for shenandoah");
869 visited.clear();
870 ShenandoahBarrierC2Support::optimize_after_expansion(visited, nstack, worklist, phase);
871 return true;
872 }
873 return false;
874 }
875
876 bool ShenandoahBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, bool is_clone_instance, ArrayCopyPhase phase) const {
877 bool is_oop = is_reference_type(type);
878 if (!is_oop) {
879 return false;
880 }
881 if (ShenandoahSATBBarrier && tightly_coupled_alloc) {
882 if (phase == Optimization) {
883 return false;
884 }
885 return !is_clone;
886 }
887 if (phase == Optimization) {
888 return !ShenandoahIUBarrier;
889 }
890 return true;
891 }
892
893 bool ShenandoahBarrierSetC2::clone_needs_barrier(Node* src, PhaseGVN& gvn) {
894 const TypeOopPtr* src_type = gvn.type(src)->is_oopptr();
895 if (src_type->isa_instptr() != nullptr) {
896 ciInstanceKlass* ik = src_type->is_instptr()->instance_klass();
897 if ((src_type->klass_is_exact() || !ik->has_subklass()) && !ik->has_injected_fields()) {
898 if (ik->has_object_fields()) {
899 return true;
900 } else {
901 if (!src_type->klass_is_exact()) {
902 Compile::current()->dependencies()->assert_leaf_type(ik);
903 }
904 }
905 } else {
906 return true;
907 }
908 } else if (src_type->isa_aryptr()) {
909 BasicType src_elem = src_type->isa_aryptr()->elem()->array_element_basic_type();
910 if (is_reference_type(src_elem, true)) {
911 return true;
912 }
913 } else {
914 return true;
915 }
916 return false;
917 }
918
919 void ShenandoahBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
920 Node* ctrl = ac->in(TypeFunc::Control);
921 Node* mem = ac->in(TypeFunc::Memory);
922 Node* src_base = ac->in(ArrayCopyNode::Src);
923 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
924 Node* dest_base = ac->in(ArrayCopyNode::Dest);
925 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
926 Node* length = ac->in(ArrayCopyNode::Length);
927
928 Node* src = phase->basic_plus_adr(src_base, src_offset);
929 Node* dest = phase->basic_plus_adr(dest_base, dest_offset);
930
931 if (ShenandoahCloneBarrier && clone_needs_barrier(src, phase->igvn())) {
932 // Check if heap is has forwarded objects. If it does, we need to call into the special
933 // routine that would fix up source references before we can continue.
934
935 enum { _heap_stable = 1, _heap_unstable, PATH_LIMIT };
936 Node* region = new RegionNode(PATH_LIMIT);
937 Node* mem_phi = new PhiNode(region, Type::MEMORY, TypeRawPtr::BOTTOM);
938
939 Node* thread = phase->transform_later(new ThreadLocalNode());
940 Node* offset = phase->igvn().MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
941 Node* gc_state_addr = phase->transform_later(new AddPNode(phase->C->top(), thread, offset));
942
943 uint gc_state_idx = Compile::AliasIdxRaw;
944 const TypePtr* gc_state_adr_type = nullptr; // debug-mode-only argument
945 debug_only(gc_state_adr_type = phase->C->get_adr_type(gc_state_idx));
946
947 Node* gc_state = phase->transform_later(new LoadBNode(ctrl, mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered));
948 int flags = ShenandoahHeap::HAS_FORWARDED;
949 if (ShenandoahIUBarrier) {
950 flags |= ShenandoahHeap::MARKING;
951 }
952 Node* stable_and = phase->transform_later(new AndINode(gc_state, phase->igvn().intcon(flags)));
953 Node* stable_cmp = phase->transform_later(new CmpINode(stable_and, phase->igvn().zerocon(T_INT)));
954 Node* stable_test = phase->transform_later(new BoolNode(stable_cmp, BoolTest::ne));
955
956 IfNode* stable_iff = phase->transform_later(new IfNode(ctrl, stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN))->as_If();
957 Node* stable_ctrl = phase->transform_later(new IfFalseNode(stable_iff));
958 Node* unstable_ctrl = phase->transform_later(new IfTrueNode(stable_iff));
959
960 // Heap is stable, no need to do anything additional
961 region->init_req(_heap_stable, stable_ctrl);
962 mem_phi->init_req(_heap_stable, mem);
963
964 // Heap is unstable, call into clone barrier stub
965 Node* call = phase->make_leaf_call(unstable_ctrl, mem,
966 ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type(),
967 CAST_FROM_FN_PTR(address, ShenandoahRuntime::shenandoah_clone_barrier),
968 "shenandoah_clone",
969 TypeRawPtr::BOTTOM,
970 src_base);
971 call = phase->transform_later(call);
972
973 ctrl = phase->transform_later(new ProjNode(call, TypeFunc::Control));
974 mem = phase->transform_later(new ProjNode(call, TypeFunc::Memory));
975 region->init_req(_heap_unstable, ctrl);
976 mem_phi->init_req(_heap_unstable, mem);
977
978 // Wire up the actual arraycopy stub now
979 ctrl = phase->transform_later(region);
980 mem = phase->transform_later(mem_phi);
981
982 const char* name = "arraycopy";
983 call = phase->make_leaf_call(ctrl, mem,
984 OptoRuntime::fast_arraycopy_Type(),
985 phase->basictype2arraycopy(T_LONG, nullptr, nullptr, true, name, true),
986 name, TypeRawPtr::BOTTOM,
987 src, dest, length
988 LP64_ONLY(COMMA phase->top()));
989 call = phase->transform_later(call);
990
991 // Hook up the whole thing into the graph
992 phase->igvn().replace_node(ac, call);
993 } else {
994 BarrierSetC2::clone_at_expansion(phase, ac);
995 }
996 }
997
998
999 // Support for macro expanded GC barriers
1000 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
1001 if (node->Opcode() == Op_ShenandoahIUBarrier) {
1002 state()->add_iu_barrier((ShenandoahIUBarrierNode*) node);
1003 }
1004 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1005 state()->add_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
1006 }
1007 }
1008
1009 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
1010 if (node->Opcode() == Op_ShenandoahIUBarrier) {
1011 state()->remove_iu_barrier((ShenandoahIUBarrierNode*) node);
1012 }
1013 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1014 state()->remove_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
1015 }
1016 }
1017
1018 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const {
1019 if (is_shenandoah_wb_pre_call(node)) {
1020 shenandoah_eliminate_wb_pre(node, ¯o->igvn());
1021 }
1022 if (ShenandoahCardBarrier && node->Opcode() == Op_CastP2X) {
1023 Node* shift = node->unique_out();
1024 Node* addp = shift->unique_out();
1025 for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) {
1026 Node* mem = addp->last_out(j);
1027 if (UseCondCardMark && mem->is_Load()) {
1028 assert(mem->Opcode() == Op_LoadB, "unexpected code shape");
1029 // The load is checking if the card has been written so
1030 // replace it with zero to fold the test.
1031 macro->replace_node(mem, macro->intcon(0));
1032 continue;
1033 }
1034 assert(mem->is_Store(), "store required");
1035 macro->replace_node(mem, mem->in(MemNode::Memory));
1036 }
1037 }
1038 }
1039
1040 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
1041 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
1042 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
1043 c = c->unique_ctrl_out();
1044 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1045 c = c->unique_ctrl_out();
1046 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1047 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
1048 assert(iff->is_If(), "expect test");
1049 if (!is_shenandoah_marking_if(igvn, iff)) {
1050 c = c->unique_ctrl_out();
1051 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1052 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
1053 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
1054 }
1055 Node* cmpx = iff->in(1)->in(1);
1056 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
1057 igvn->rehash_node_delayed(call);
1058 call->del_req(call->req()-1);
1059 }
1060
1061 void ShenandoahBarrierSetC2::enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {
1062 if (node->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(node)) {
1063 igvn->add_users_to_worklist(node);
1064 }
1065 }
1066
1067 void ShenandoahBarrierSetC2::eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {
1068 for (uint i = 0; i < useful.size(); i++) {
1069 Node* n = useful.at(i);
1070 if (n->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(n)) {
1071 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1072 C->record_for_igvn(n->fast_out(i));
1073 }
1074 }
1075 }
1076 for (int i = state()->iu_barriers_count() - 1; i >= 0; i--) {
1077 ShenandoahIUBarrierNode* n = state()->iu_barrier(i);
1078 if (!useful.member(n)) {
1079 state()->remove_iu_barrier(n);
1080 }
1081 }
1082 for (int i = state()->load_reference_barriers_count() - 1; i >= 0; i--) {
1083 ShenandoahLoadReferenceBarrierNode* n = state()->load_reference_barrier(i);
1084 if (!useful.member(n)) {
1085 state()->remove_load_reference_barrier(n);
1086 }
1087 }
1088 }
1089
1090 void* ShenandoahBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
1091 return new(comp_arena) ShenandoahBarrierSetC2State(comp_arena);
1092 }
1093
1094 ShenandoahBarrierSetC2State* ShenandoahBarrierSetC2::state() const {
1095 return reinterpret_cast<ShenandoahBarrierSetC2State*>(Compile::current()->barrier_set_state());
1096 }
1097
1098 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
1099 // expanded later, then now is the time to do so.
1100 bool ShenandoahBarrierSetC2::expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
1101
1102 #ifdef ASSERT
1103 void ShenandoahBarrierSetC2::verify_gc_barriers(Compile* compile, CompilePhase phase) const {
1104 if (ShenandoahVerifyOptoBarriers && phase == BarrierSetC2::BeforeMacroExpand) {
1105 ShenandoahBarrierC2Support::verify(Compile::current()->root());
1106 } else if (phase == BarrierSetC2::BeforeCodeGen) {
1107 // Verify Shenandoah pre-barriers
1108 const int marking_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset());
1109
1110 Unique_Node_List visited;
1111 Node_List worklist;
1112 // We're going to walk control flow backwards starting from the Root
1113 worklist.push(compile->root());
1114 while (worklist.size() > 0) {
1115 Node *x = worklist.pop();
1116 if (x == nullptr || x == compile->top()) continue;
1117 if (visited.member(x)) {
1118 continue;
1119 } else {
1120 visited.push(x);
1121 }
1122
1123 if (x->is_Region()) {
1124 for (uint i = 1; i < x->req(); i++) {
1125 worklist.push(x->in(i));
1126 }
1127 } else {
1128 worklist.push(x->in(0));
1129 // We are looking for the pattern:
1130 // /->ThreadLocal
1131 // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
1132 // \->ConI(0)
1133 // We want to verify that the If and the LoadB have the same control
1134 // See GraphKit::g1_write_barrier_pre()
1135 if (x->is_If()) {
1136 IfNode *iff = x->as_If();
1137 if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
1138 CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
1139 if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
1140 && cmp->in(1)->is_Load()) {
1141 LoadNode *load = cmp->in(1)->as_Load();
1142 if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
1143 && load->in(2)->in(3)->is_Con()
1144 && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
1145
1146 Node *if_ctrl = iff->in(0);
1147 Node *load_ctrl = load->in(0);
1148
1149 if (if_ctrl != load_ctrl) {
1150 // Skip possible CProj->NeverBranch in infinite loops
1151 if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
1152 && if_ctrl->in(0)->is_NeverBranch()) {
1153 if_ctrl = if_ctrl->in(0)->in(0);
1154 }
1155 }
1156 assert(load_ctrl != nullptr && if_ctrl == load_ctrl, "controls must match");
1157 }
1158 }
1159 }
1160 }
1161 }
1162 }
1163 }
1164 }
1165 #endif
1166
1167 Node* ShenandoahBarrierSetC2::ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const {
1168 if (is_shenandoah_wb_pre_call(n)) {
1169 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1170 if (n->req() > cnt) {
1171 Node* addp = n->in(cnt);
1172 if (has_only_shenandoah_wb_pre_uses(addp)) {
1173 n->del_req(cnt);
1174 if (can_reshape) {
1175 phase->is_IterGVN()->_worklist.push(addp);
1176 }
1177 return n;
1178 }
1179 }
1180 }
1181 if (n->Opcode() == Op_CmpP) {
1182 Node* in1 = n->in(1);
1183 Node* in2 = n->in(2);
1184
1185 // If one input is null, then step over the strong LRB barriers on the other input
1186 if (in1->bottom_type() == TypePtr::NULL_PTR &&
1187 !((in2->Opcode() == Op_ShenandoahLoadReferenceBarrier) &&
1188 !ShenandoahBarrierSet::is_strong_access(((ShenandoahLoadReferenceBarrierNode*)in2)->decorators()))) {
1189 in2 = step_over_gc_barrier(in2);
1190 }
1191 if (in2->bottom_type() == TypePtr::NULL_PTR &&
1192 !((in1->Opcode() == Op_ShenandoahLoadReferenceBarrier) &&
1193 !ShenandoahBarrierSet::is_strong_access(((ShenandoahLoadReferenceBarrierNode*)in1)->decorators()))) {
1194 in1 = step_over_gc_barrier(in1);
1195 }
1196
1197 if (in1 != n->in(1)) {
1198 n->set_req_X(1, in1, phase);
1199 assert(in2 == n->in(2), "only one change");
1200 return n;
1201 }
1202 if (in2 != n->in(2)) {
1203 n->set_req_X(2, in2, phase);
1204 return n;
1205 }
1206 } else if (can_reshape &&
1207 n->Opcode() == Op_If &&
1208 ShenandoahBarrierC2Support::is_heap_stable_test(n) &&
1209 n->in(0) != nullptr &&
1210 n->outcnt() == 2) {
1211 Node* dom = n->in(0);
1212 Node* prev_dom = n;
1213 int op = n->Opcode();
1214 int dist = 16;
1215 // Search up the dominator tree for another heap stable test
1216 while (dom->Opcode() != op || // Not same opcode?
1217 !ShenandoahBarrierC2Support::is_heap_stable_test(dom) || // Not same input 1?
1218 prev_dom->in(0) != dom) { // One path of test does not dominate?
1219 if (dist < 0) return nullptr;
1220
1221 dist--;
1222 prev_dom = dom;
1223 dom = IfNode::up_one_dom(dom);
1224 if (!dom) return nullptr;
1225 }
1226
1227 // Check that we did not follow a loop back to ourselves
1228 if (n == dom) {
1229 return nullptr;
1230 }
1231
1232 return n->as_If()->dominated_by(prev_dom, phase->is_IterGVN());
1233 }
1234
1235 return nullptr;
1236 }
1237
1238 bool ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(Node* n) {
1239 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1240 Node* u = n->fast_out(i);
1241 if (!is_shenandoah_wb_pre_call(u)) {
1242 return false;
1243 }
1244 }
1245 return n->outcnt() > 0;
1246 }
1247
1248 bool ShenandoahBarrierSetC2::final_graph_reshaping(Compile* compile, Node* n, uint opcode, Unique_Node_List& dead_nodes) const {
1249 switch (opcode) {
1250 case Op_CallLeaf:
1251 case Op_CallLeafNoFP: {
1252 assert (n->is_Call(), "");
1253 CallNode *call = n->as_Call();
1254 if (ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(call)) {
1255 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1256 if (call->req() > cnt) {
1257 assert(call->req() == cnt + 1, "only one extra input");
1258 Node *addp = call->in(cnt);
1259 assert(!ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(addp), "useless address computation?");
1260 call->del_req(cnt);
1261 }
1262 }
1263 return false;
1264 }
1265 case Op_ShenandoahCompareAndSwapP:
1266 case Op_ShenandoahCompareAndSwapN:
1267 case Op_ShenandoahWeakCompareAndSwapN:
1268 case Op_ShenandoahWeakCompareAndSwapP:
1269 case Op_ShenandoahCompareAndExchangeP:
1270 case Op_ShenandoahCompareAndExchangeN:
1271 return true;
1272 case Op_ShenandoahLoadReferenceBarrier:
1273 assert(false, "should have been expanded already");
1274 return true;
1275 default:
1276 return false;
1277 }
1278 }
1279
1280 bool ShenandoahBarrierSetC2::escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const {
1281 switch (opcode) {
1282 case Op_ShenandoahCompareAndExchangeP:
1283 case Op_ShenandoahCompareAndExchangeN:
1284 conn_graph->add_objload_to_connection_graph(n, delayed_worklist);
1285 // fallthrough
1286 case Op_ShenandoahWeakCompareAndSwapP:
1287 case Op_ShenandoahWeakCompareAndSwapN:
1288 case Op_ShenandoahCompareAndSwapP:
1289 case Op_ShenandoahCompareAndSwapN:
1290 conn_graph->add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1291 return true;
1292 case Op_StoreP: {
1293 Node* adr = n->in(MemNode::Address);
1294 const Type* adr_type = gvn->type(adr);
1295 // Pointer stores in Shenandoah barriers looks like unsafe access.
1296 // Ignore such stores to be able scalar replace non-escaping
1297 // allocations.
1298 if (adr_type->isa_rawptr() && adr->is_AddP()) {
1299 Node* base = conn_graph->get_addp_base(adr);
1300 if (base->Opcode() == Op_LoadP &&
1301 base->in(MemNode::Address)->is_AddP()) {
1302 adr = base->in(MemNode::Address);
1303 Node* tls = conn_graph->get_addp_base(adr);
1304 if (tls->Opcode() == Op_ThreadLocal) {
1305 int offs = (int) gvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1306 const int buf_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
1307 if (offs == buf_offset) {
1308 return true; // Pre barrier previous oop value store.
1309 }
1310 }
1311 }
1312 }
1313 return false;
1314 }
1315 case Op_ShenandoahIUBarrier:
1316 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1317 break;
1318 case Op_ShenandoahLoadReferenceBarrier:
1319 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), delayed_worklist);
1320 return true;
1321 default:
1322 // Nothing
1323 break;
1324 }
1325 return false;
1326 }
1327
1328 bool ShenandoahBarrierSetC2::escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const {
1329 switch (opcode) {
1330 case Op_ShenandoahCompareAndExchangeP:
1331 case Op_ShenandoahCompareAndExchangeN: {
1332 Node *adr = n->in(MemNode::Address);
1333 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, adr, nullptr);
1334 // fallthrough
1335 }
1336 case Op_ShenandoahCompareAndSwapP:
1337 case Op_ShenandoahCompareAndSwapN:
1338 case Op_ShenandoahWeakCompareAndSwapP:
1339 case Op_ShenandoahWeakCompareAndSwapN:
1340 return conn_graph->add_final_edges_unsafe_access(n, opcode);
1341 case Op_ShenandoahIUBarrier:
1342 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), nullptr);
1343 return true;
1344 case Op_ShenandoahLoadReferenceBarrier:
1345 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), nullptr);
1346 return true;
1347 default:
1348 // Nothing
1349 break;
1350 }
1351 return false;
1352 }
1353
1354 bool ShenandoahBarrierSetC2::escape_has_out_with_unsafe_object(Node* n) const {
1355 return n->has_out_with(Op_ShenandoahCompareAndExchangeP) || n->has_out_with(Op_ShenandoahCompareAndExchangeN) ||
1356 n->has_out_with(Op_ShenandoahCompareAndSwapP, Op_ShenandoahCompareAndSwapN, Op_ShenandoahWeakCompareAndSwapP, Op_ShenandoahWeakCompareAndSwapN);
1357
1358 }
1359
1360 bool ShenandoahBarrierSetC2::matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const {
1361 switch (opcode) {
1362 case Op_ShenandoahCompareAndExchangeP:
1363 case Op_ShenandoahCompareAndExchangeN:
1364 case Op_ShenandoahWeakCompareAndSwapP:
1365 case Op_ShenandoahWeakCompareAndSwapN:
1366 case Op_ShenandoahCompareAndSwapP:
1367 case Op_ShenandoahCompareAndSwapN: { // Convert trinary to binary-tree
1368 Node* newval = n->in(MemNode::ValueIn);
1369 Node* oldval = n->in(LoadStoreConditionalNode::ExpectedIn);
1370 Node* pair = new BinaryNode(oldval, newval);
1371 n->set_req(MemNode::ValueIn,pair);
1372 n->del_req(LoadStoreConditionalNode::ExpectedIn);
1373 return true;
1374 }
1375 default:
1376 break;
1377 }
1378 return false;
1379 }
1380
1381 bool ShenandoahBarrierSetC2::matcher_is_store_load_barrier(Node* x, uint xop) const {
1382 return xop == Op_ShenandoahCompareAndExchangeP ||
1383 xop == Op_ShenandoahCompareAndExchangeN ||
1384 xop == Op_ShenandoahWeakCompareAndSwapP ||
1385 xop == Op_ShenandoahWeakCompareAndSwapN ||
1386 xop == Op_ShenandoahCompareAndSwapN ||
1387 xop == Op_ShenandoahCompareAndSwapP;
1388 }