1 /*
2 * Copyright (c) 2018, 2019, 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 "gc/shared/barrierSet.hpp"
27 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.hpp"
29 #include "gc/shenandoah/shenandoahHeap.hpp"
30 #include "gc/shenandoah/shenandoahHeuristics.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 "opto/arraycopynode.hpp"
36 #include "opto/escape.hpp"
37 #include "opto/graphKit.hpp"
38 #include "opto/idealKit.hpp"
39 #include "opto/macro.hpp"
40 #include "opto/movenode.hpp"
41 #include "opto/narrowptrnode.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/runtime.hpp"
44
45 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
46 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
47 }
48
49 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
50 : _enqueue_barriers(new (comp_arena) GrowableArray<ShenandoahEnqueueBarrierNode*>(comp_arena, 8, 0, NULL)),
51 _load_reference_barriers(new (comp_arena) GrowableArray<ShenandoahLoadReferenceBarrierNode*>(comp_arena, 8, 0, NULL)) {
52 }
53
54 int ShenandoahBarrierSetC2State::enqueue_barriers_count() const {
55 return _enqueue_barriers->length();
56 }
57
58 ShenandoahEnqueueBarrierNode* ShenandoahBarrierSetC2State::enqueue_barrier(int idx) const {
59 return _enqueue_barriers->at(idx);
60 }
61
62 void ShenandoahBarrierSetC2State::add_enqueue_barrier(ShenandoahEnqueueBarrierNode * n) {
63 assert(!_enqueue_barriers->contains(n), "duplicate entry in barrier list");
64 _enqueue_barriers->append(n);
65 }
66
67 void ShenandoahBarrierSetC2State::remove_enqueue_barrier(ShenandoahEnqueueBarrierNode * n) {
68 if (_enqueue_barriers->contains(n)) {
69 _enqueue_barriers->remove(n);
70 }
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_storeval_barrier(GraphKit* kit, Node* obj) const {
93 if (ShenandoahStoreValEnqueueBarrier) {
94 obj = shenandoah_enqueue_barrier(kit, 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 == NULL) {
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 == NULL) {
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 == NULL || 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(obj != NULL, "must have a base");
204 assert(adr != NULL, "where are loading from?");
205 assert(pre_val == NULL, "loaded already?");
206 assert(val_type != NULL, "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 != NULL, "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 G1 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 != NULL)
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 != NULL)
283 } __ end_if(); // (!marking)
284
285 // Final sync IdealKit and GraphKit.
286 kit->final_sync(ideal);
287
288 if (ShenandoahSATBBarrier && adr != NULL) {
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)) ||
308 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow)) ||
309 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_native));
310 }
311
312 bool ShenandoahBarrierSetC2::is_shenandoah_marking_if(PhaseTransform *phase, Node* n) {
313 if (n->Opcode() != Op_If) {
314 return false;
315 }
316
317 Node* bol = n->in(1);
318 assert(bol->is_Bool(), "");
319 Node* cmpx = bol->in(1);
320 if (bol->as_Bool()->_test._test == BoolTest::ne &&
321 cmpx->is_Cmp() && cmpx->in(2) == phase->intcon(0) &&
322 is_shenandoah_state_load(cmpx->in(1)->in(1)) &&
323 cmpx->in(1)->in(2)->is_Con() &&
324 cmpx->in(1)->in(2) == phase->intcon(ShenandoahHeap::MARKING)) {
325 return true;
326 }
327
328 return false;
329 }
330
331 bool ShenandoahBarrierSetC2::is_shenandoah_state_load(Node* n) {
332 if (!n->is_Load()) return false;
333 const int state_offset = in_bytes(ShenandoahThreadLocalData::gc_state_offset());
334 return n->in(2)->is_AddP() && n->in(2)->in(2)->Opcode() == Op_ThreadLocal
335 && n->in(2)->in(3)->is_Con()
336 && n->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == state_offset;
337 }
338
339 void ShenandoahBarrierSetC2::shenandoah_write_barrier_pre(GraphKit* kit,
340 bool do_load,
341 Node* obj,
342 Node* adr,
343 uint alias_idx,
344 Node* val,
345 const TypeOopPtr* val_type,
346 Node* pre_val,
347 BasicType bt) const {
348 if (ShenandoahSATBBarrier) {
349 IdealKit ideal(kit);
350 kit->sync_kit(ideal);
351
352 satb_write_barrier_pre(kit, do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
353
354 ideal.sync_kit(kit);
355 kit->final_sync(ideal);
356 }
357 }
358
359 Node* ShenandoahBarrierSetC2::shenandoah_enqueue_barrier(GraphKit* kit, Node* pre_val) const {
360 return kit->gvn().transform(new ShenandoahEnqueueBarrierNode(pre_val));
361 }
362
363 // Helper that guards and inserts a pre-barrier.
364 void ShenandoahBarrierSetC2::insert_pre_barrier(GraphKit* kit, Node* base_oop, Node* offset,
365 Node* pre_val, bool need_mem_bar) const {
366 // We could be accessing the referent field of a reference object. If so, when G1
367 // is enabled, we need to log the value in the referent field in an SATB buffer.
368 // This routine performs some compile time filters and generates suitable
369 // runtime filters that guard the pre-barrier code.
370 // Also add memory barrier for non volatile load from the referent field
371 // to prevent commoning of loads across safepoint.
372
373 // Some compile time checks.
374
375 // If offset is a constant, is it java_lang_ref_Reference::_reference_offset?
376 const TypeX* otype = offset->find_intptr_t_type();
377 if (otype != NULL && otype->is_con() &&
378 otype->get_con() != java_lang_ref_Reference::referent_offset) {
379 // Constant offset but not the reference_offset so just return
380 return;
381 }
382
383 // We only need to generate the runtime guards for instances.
384 const TypeOopPtr* btype = base_oop->bottom_type()->isa_oopptr();
385 if (btype != NULL) {
386 if (btype->isa_aryptr()) {
387 // Array type so nothing to do
388 return;
389 }
390
391 const TypeInstPtr* itype = btype->isa_instptr();
392 if (itype != NULL) {
393 // Can the klass of base_oop be statically determined to be
394 // _not_ a sub-class of Reference and _not_ Object?
395 ciKlass* klass = itype->klass();
396 if ( klass->is_loaded() &&
397 !klass->is_subtype_of(kit->env()->Reference_klass()) &&
398 !kit->env()->Object_klass()->is_subtype_of(klass)) {
399 return;
400 }
401 }
402 }
403
404 // The compile time filters did not reject base_oop/offset so
405 // we need to generate the following runtime filters
406 //
407 // if (offset == java_lang_ref_Reference::_reference_offset) {
408 // if (instance_of(base, java.lang.ref.Reference)) {
409 // pre_barrier(_, pre_val, ...);
410 // }
411 // }
412
413 float likely = PROB_LIKELY( 0.999);
414 float unlikely = PROB_UNLIKELY(0.999);
415
416 IdealKit ideal(kit);
417
418 Node* referent_off = __ ConX(java_lang_ref_Reference::referent_offset);
419
420 __ if_then(offset, BoolTest::eq, referent_off, unlikely); {
421 // Update graphKit memory and control from IdealKit.
422 kit->sync_kit(ideal);
423
424 Node* ref_klass_con = kit->makecon(TypeKlassPtr::make(kit->env()->Reference_klass()));
425 Node* is_instof = kit->gen_instanceof(base_oop, ref_klass_con);
426
427 // Update IdealKit memory and control from graphKit.
428 __ sync_kit(kit);
429
430 Node* one = __ ConI(1);
431 // is_instof == 0 if base_oop == NULL
432 __ if_then(is_instof, BoolTest::eq, one, unlikely); {
433
434 // Update graphKit from IdeakKit.
435 kit->sync_kit(ideal);
436
437 // Use the pre-barrier to record the value in the referent field
438 satb_write_barrier_pre(kit, false /* do_load */,
439 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
440 pre_val /* pre_val */,
441 T_OBJECT);
442 if (need_mem_bar) {
443 // Add memory barrier to prevent commoning reads from this field
444 // across safepoint since GC can change its value.
445 kit->insert_mem_bar(Op_MemBarCPUOrder);
446 }
447 // Update IdealKit from graphKit.
448 __ sync_kit(kit);
449
450 } __ end_if(); // _ref_type != ref_none
451 } __ end_if(); // offset == referent_offset
452
453 // Final sync IdealKit and GraphKit.
454 kit->final_sync(ideal);
455 }
456
457 #undef __
458
459 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
460 const Type **fields = TypeTuple::fields(2);
461 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
462 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
463 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
464
465 // create result type (range)
466 fields = TypeTuple::fields(0);
467 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
468
469 return TypeFunc::make(domain, range);
470 }
471
472 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
473 const Type **fields = TypeTuple::fields(1);
474 fields[TypeFunc::Parms+0] = TypeOopPtr::NOTNULL; // src oop
475 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
476
477 // create result type (range)
478 fields = TypeTuple::fields(0);
479 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
480
481 return TypeFunc::make(domain, range);
482 }
483
484 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type() {
485 const Type **fields = TypeTuple::fields(2);
486 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
487 fields[TypeFunc::Parms+1] = TypeRawPtr::BOTTOM; // original load address
488
489 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
490
491 // create result type (range)
492 fields = TypeTuple::fields(1);
493 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL;
494 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
495
496 return TypeFunc::make(domain, range);
497 }
498
499 Node* ShenandoahBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
500 DecoratorSet decorators = access.decorators();
501
502 const TypePtr* adr_type = access.addr().type();
503 Node* adr = access.addr().node();
504
505 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
506 bool on_heap = (decorators & IN_HEAP) != 0;
507
508 if (!access.is_oop() || (!on_heap && !anonymous)) {
509 return BarrierSetC2::store_at_resolved(access, val);
510 }
511
512 if (access.is_parse_access()) {
513 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
514 GraphKit* kit = parse_access.kit();
515
516 uint adr_idx = kit->C->get_alias_index(adr_type);
517 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
518 Node* value = val.node();
519 value = shenandoah_storeval_barrier(kit, value);
520 val.set_node(value);
521 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
522 static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
523 } else {
524 assert(access.is_opt_access(), "only for optimization passes");
525 assert(((decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0 || !ShenandoahSATBBarrier) && (decorators & C2_ARRAY_COPY) != 0, "unexpected caller of this code");
526 C2OptAccess& opt_access = static_cast<C2OptAccess&>(access);
527 PhaseGVN& gvn = opt_access.gvn();
528 MergeMemNode* mm = opt_access.mem();
529
530 if (ShenandoahStoreValEnqueueBarrier) {
531 Node* enqueue = gvn.transform(new ShenandoahEnqueueBarrierNode(val.node()));
532 val.set_node(enqueue);
533 }
534 }
535 return BarrierSetC2::store_at_resolved(access, val);
536 }
537
538 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
539 // 1: non-reference load, no additional barrier is needed
540 if (!access.is_oop()) {
541 return BarrierSetC2::load_at_resolved(access, val_type);;
542 }
543
544 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
545 DecoratorSet decorators = access.decorators();
546 BasicType type = access.type();
547
548 // 2: apply LRB if needed
549 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
550 load = new ShenandoahLoadReferenceBarrierNode(NULL,
551 load,
552 ShenandoahBarrierSet::use_load_reference_barrier_native(decorators, type));
553 if (access.is_parse_access()) {
554 load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
555 } else {
556 load = static_cast<C2OptAccess &>(access).gvn().transform(load);
557 }
558 }
559
560 // 3: apply keep-alive barrier if needed
561 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
562 Node* top = Compile::current()->top();
563 Node* adr = access.addr().node();
564 Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : top;
565 Node* obj = access.base();
566
567 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
568 bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0;
569 bool is_traversal_mode = ShenandoahHeap::heap()->is_traversal_mode();
570 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0 || is_traversal_mode;
571
572 // If we are reading the value of the referent field of a Reference
573 // object (either by using Unsafe directly or through reflection)
574 // then, if SATB is enabled, we need to record the referent in an
575 // SATB log buffer using the pre-barrier mechanism.
576 // Also we need to add memory barrier to prevent commoning reads
577 // from this field across safepoint since GC can change its value.
578 if (!on_weak_ref || (unknown && (offset == top || obj == top)) || !keep_alive) {
579 return load;
580 }
581
582 assert(access.is_parse_access(), "entry not supported at optimization time");
583 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
584 GraphKit* kit = parse_access.kit();
585 bool mismatched = (decorators & C2_MISMATCHED) != 0;
586 bool is_unordered = (decorators & MO_UNORDERED) != 0;
587 bool in_native = (decorators & IN_NATIVE) != 0;
588 bool need_cpu_mem_bar = !is_unordered || mismatched || in_native;
589
590 if (on_weak_ref) {
591 // Use the pre-barrier to record the value in the referent field
592 satb_write_barrier_pre(kit, false /* do_load */,
593 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
594 load /* pre_val */, T_OBJECT);
595 // Add memory barrier to prevent commoning reads from this field
596 // across safepoint since GC can change its value.
597 kit->insert_mem_bar(Op_MemBarCPUOrder);
598 } else if (unknown) {
599 // We do not require a mem bar inside pre_barrier if need_mem_bar
600 // is set: the barriers would be emitted by us.
601 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
602 }
603 }
604
605 return load;
606 }
607
608 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
609 Node* new_val, const Type* value_type) const {
610 GraphKit* kit = access.kit();
611 if (access.is_oop()) {
612 new_val = shenandoah_storeval_barrier(kit, new_val);
613 shenandoah_write_barrier_pre(kit, false /* do_load */,
614 NULL, NULL, max_juint, NULL, NULL,
615 expected_val /* pre_val */, T_OBJECT);
616
617 MemNode::MemOrd mo = access.mem_node_mo();
618 Node* mem = access.memory();
619 Node* adr = access.addr().node();
620 const TypePtr* adr_type = access.addr().type();
621 Node* load_store = NULL;
622
623 #ifdef _LP64
624 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
625 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
626 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
627 if (ShenandoahCASBarrier) {
628 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
629 } else {
630 load_store = kit->gvn().transform(new CompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
631 }
632 } else
633 #endif
634 {
635 if (ShenandoahCASBarrier) {
636 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
637 } else {
638 load_store = kit->gvn().transform(new CompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
639 }
640 }
641
642 access.set_raw_access(load_store);
643 pin_atomic_op(access);
644
645 #ifdef _LP64
646 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
647 load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
648 }
649 #endif
650 load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, load_store, false));
651 return load_store;
652 }
653 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
654 }
655
656 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
657 Node* new_val, const Type* value_type) const {
658 GraphKit* kit = access.kit();
659 if (access.is_oop()) {
660 new_val = shenandoah_storeval_barrier(kit, new_val);
661 shenandoah_write_barrier_pre(kit, false /* do_load */,
662 NULL, NULL, max_juint, NULL, NULL,
663 expected_val /* pre_val */, T_OBJECT);
664 DecoratorSet decorators = access.decorators();
665 MemNode::MemOrd mo = access.mem_node_mo();
666 Node* mem = access.memory();
667 bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
668 Node* load_store = NULL;
669 Node* adr = access.addr().node();
670 #ifdef _LP64
671 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
672 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
673 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
674 if (ShenandoahCASBarrier) {
675 if (is_weak_cas) {
676 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
677 } else {
678 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
679 }
680 } else {
681 if (is_weak_cas) {
682 load_store = kit->gvn().transform(new WeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
683 } else {
684 load_store = kit->gvn().transform(new CompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
685 }
686 }
687 } else
688 #endif
689 {
690 if (ShenandoahCASBarrier) {
691 if (is_weak_cas) {
692 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
693 } else {
694 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
695 }
696 } else {
697 if (is_weak_cas) {
698 load_store = kit->gvn().transform(new WeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
699 } else {
700 load_store = kit->gvn().transform(new CompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
701 }
702 }
703 }
704 access.set_raw_access(load_store);
705 pin_atomic_op(access);
706 return load_store;
707 }
708 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
709 }
710
711 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* val, const Type* value_type) const {
712 GraphKit* kit = access.kit();
713 if (access.is_oop()) {
714 val = shenandoah_storeval_barrier(kit, val);
715 }
716 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
717 if (access.is_oop()) {
718 result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, result, false));
719 shenandoah_write_barrier_pre(kit, false /* do_load */,
720 NULL, NULL, max_juint, NULL, NULL,
721 result /* pre_val */, T_OBJECT);
722 }
723 return result;
724 }
725
726 // Support for GC barriers emitted during parsing
727 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
728 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) return true;
729 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
730 return false;
731 }
732 CallLeafNode *call = node->as_CallLeaf();
733 if (call->_name == NULL) {
734 return false;
735 }
736
737 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
738 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
739 strcmp(call->_name, "shenandoah_wb_pre") == 0;
740 }
741
742 Node* ShenandoahBarrierSetC2::step_over_gc_barrier(Node* c) const {
743 if (c == NULL) {
744 return c;
745 }
746 if (c->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
747 return c->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
748 }
749 if (c->Opcode() == Op_ShenandoahEnqueueBarrier) {
750 c = c->in(1);
751 }
752 return c;
753 }
754
755 bool ShenandoahBarrierSetC2::expand_barriers(Compile* C, PhaseIterGVN& igvn) const {
756 return !ShenandoahBarrierC2Support::expand(C, igvn);
757 }
758
759 bool ShenandoahBarrierSetC2::optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const {
760 if (mode == LoopOptsShenandoahExpand) {
761 assert(UseShenandoahGC, "only for shenandoah");
762 ShenandoahBarrierC2Support::pin_and_expand(phase);
763 return true;
764 } else if (mode == LoopOptsShenandoahPostExpand) {
765 assert(UseShenandoahGC, "only for shenandoah");
766 visited.clear();
767 ShenandoahBarrierC2Support::optimize_after_expansion(visited, nstack, worklist, phase);
768 return true;
769 }
770 return false;
771 }
772
773 bool ShenandoahBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const {
774 bool is_oop = is_reference_type(type);
775 if (!is_oop) {
776 return false;
777 }
778 if (tightly_coupled_alloc) {
779 if (phase == Optimization) {
780 return false;
781 }
782 return !is_clone;
783 }
784 if (phase == Optimization) {
785 return !ShenandoahStoreValEnqueueBarrier;
786 }
787 return true;
788 }
789
790 bool ShenandoahBarrierSetC2::clone_needs_barrier(Node* src, PhaseGVN& gvn) {
791 const TypeOopPtr* src_type = gvn.type(src)->is_oopptr();
792 if (src_type->isa_instptr() != NULL) {
793 ciInstanceKlass* ik = src_type->klass()->as_instance_klass();
794 if ((src_type->klass_is_exact() || (!ik->is_interface() && !ik->has_subklass())) && !ik->has_injected_fields()) {
795 if (ik->has_object_fields()) {
796 return true;
797 } else {
798 if (!src_type->klass_is_exact()) {
799 Compile::current()->dependencies()->assert_leaf_type(ik);
800 }
801 }
802 } else {
803 return true;
804 }
805 } else if (src_type->isa_aryptr()) {
806 BasicType src_elem = src_type->klass()->as_array_klass()->element_type()->basic_type();
807 if (is_reference_type(src_elem)) {
808 return true;
809 }
810 } else {
811 return true;
812 }
813 return false;
814 }
815
816 void ShenandoahBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
817 Node* ctrl = ac->in(TypeFunc::Control);
818 Node* mem = ac->in(TypeFunc::Memory);
819 Node* src_base = ac->in(ArrayCopyNode::Src);
820 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
821 Node* dest_base = ac->in(ArrayCopyNode::Dest);
822 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
823 Node* length = ac->in(ArrayCopyNode::Length);
824
825 Node* src = phase->basic_plus_adr(src_base, src_offset);
826 Node* dest = phase->basic_plus_adr(dest_base, dest_offset);
827
828 if (ShenandoahCloneBarrier && clone_needs_barrier(src, phase->igvn())) {
829 // Check if heap is has forwarded objects. If it does, we need to call into the special
830 // routine that would fix up source references before we can continue.
831
832 enum { _heap_stable = 1, _heap_unstable, PATH_LIMIT };
833 Node* region = new RegionNode(PATH_LIMIT);
834 Node* mem_phi = new PhiNode(region, Type::MEMORY, TypeRawPtr::BOTTOM);
835
836 Node* thread = phase->transform_later(new ThreadLocalNode());
837 Node* offset = phase->igvn().MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
838 Node* gc_state_addr = phase->transform_later(new AddPNode(phase->C->top(), thread, offset));
839
840 uint gc_state_idx = Compile::AliasIdxRaw;
841 const TypePtr* gc_state_adr_type = NULL; // debug-mode-only argument
842 debug_only(gc_state_adr_type = phase->C->get_adr_type(gc_state_idx));
843
844 Node* gc_state = phase->transform_later(new LoadBNode(ctrl, mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered));
845 Node* stable_and = phase->transform_later(new AndINode(gc_state, phase->igvn().intcon(ShenandoahHeap::HAS_FORWARDED)));
846 Node* stable_cmp = phase->transform_later(new CmpINode(stable_and, phase->igvn().zerocon(T_INT)));
847 Node* stable_test = phase->transform_later(new BoolNode(stable_cmp, BoolTest::ne));
848
849 IfNode* stable_iff = phase->transform_later(new IfNode(ctrl, stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN))->as_If();
850 Node* stable_ctrl = phase->transform_later(new IfFalseNode(stable_iff));
851 Node* unstable_ctrl = phase->transform_later(new IfTrueNode(stable_iff));
852
853 // Heap is stable, no need to do anything additional
854 region->init_req(_heap_stable, stable_ctrl);
855 mem_phi->init_req(_heap_stable, mem);
856
857 // Heap is unstable, call into clone barrier stub
858 Node* call = phase->make_leaf_call(unstable_ctrl, mem,
859 ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type(),
860 CAST_FROM_FN_PTR(address, ShenandoahRuntime::shenandoah_clone_barrier),
861 "shenandoah_clone",
862 TypeRawPtr::BOTTOM,
863 src_base);
864 call = phase->transform_later(call);
865
866 ctrl = phase->transform_later(new ProjNode(call, TypeFunc::Control));
867 mem = phase->transform_later(new ProjNode(call, TypeFunc::Memory));
868 region->init_req(_heap_unstable, ctrl);
869 mem_phi->init_req(_heap_unstable, mem);
870
871 // Wire up the actual arraycopy stub now
872 ctrl = phase->transform_later(region);
873 mem = phase->transform_later(mem_phi);
874
875 const char* name = "arraycopy";
876 call = phase->make_leaf_call(ctrl, mem,
877 OptoRuntime::fast_arraycopy_Type(),
878 phase->basictype2arraycopy(T_LONG, NULL, NULL, true, name, true),
879 name, TypeRawPtr::BOTTOM,
880 src, dest, length
881 LP64_ONLY(COMMA phase->top()));
882 call = phase->transform_later(call);
883
884 // Hook up the whole thing into the graph
885 phase->igvn().replace_node(ac, call);
886 } else {
887 BarrierSetC2::clone_at_expansion(phase, ac);
888 }
889 }
890
891
892 // Support for macro expanded GC barriers
893 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
894 if (node->Opcode() == Op_ShenandoahEnqueueBarrier) {
895 state()->add_enqueue_barrier((ShenandoahEnqueueBarrierNode*) node);
896 }
897 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
898 state()->add_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
899 }
900 }
901
902 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
903 if (node->Opcode() == Op_ShenandoahEnqueueBarrier) {
904 state()->remove_enqueue_barrier((ShenandoahEnqueueBarrierNode*) node);
905 }
906 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
907 state()->remove_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
908 }
909 }
910
911 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* n) const {
912 if (is_shenandoah_wb_pre_call(n)) {
913 shenandoah_eliminate_wb_pre(n, ¯o->igvn());
914 }
915 }
916
917 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
918 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
919 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
920 c = c->unique_ctrl_out();
921 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
922 c = c->unique_ctrl_out();
923 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
924 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
925 assert(iff->is_If(), "expect test");
926 if (!is_shenandoah_marking_if(igvn, iff)) {
927 c = c->unique_ctrl_out();
928 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
929 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
930 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
931 }
932 Node* cmpx = iff->in(1)->in(1);
933 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
934 igvn->rehash_node_delayed(call);
935 call->del_req(call->req()-1);
936 }
937
938 void ShenandoahBarrierSetC2::enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {
939 if (node->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(node)) {
940 igvn->add_users_to_worklist(node);
941 }
942 }
943
944 void ShenandoahBarrierSetC2::eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {
945 for (uint i = 0; i < useful.size(); i++) {
946 Node* n = useful.at(i);
947 if (n->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(n)) {
948 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
949 C->record_for_igvn(n->fast_out(i));
950 }
951 }
952 }
953 for (int i = state()->enqueue_barriers_count() - 1; i >= 0; i--) {
954 ShenandoahEnqueueBarrierNode* n = state()->enqueue_barrier(i);
955 if (!useful.member(n)) {
956 state()->remove_enqueue_barrier(n);
957 }
958 }
959 for (int i = state()->load_reference_barriers_count() - 1; i >= 0; i--) {
960 ShenandoahLoadReferenceBarrierNode* n = state()->load_reference_barrier(i);
961 if (!useful.member(n)) {
962 state()->remove_load_reference_barrier(n);
963 }
964 }
965 }
966
967 void* ShenandoahBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
968 return new(comp_arena) ShenandoahBarrierSetC2State(comp_arena);
969 }
970
971 ShenandoahBarrierSetC2State* ShenandoahBarrierSetC2::state() const {
972 return reinterpret_cast<ShenandoahBarrierSetC2State*>(Compile::current()->barrier_set_state());
973 }
974
975 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
976 // expanded later, then now is the time to do so.
977 bool ShenandoahBarrierSetC2::expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
978
979 #ifdef ASSERT
980 void ShenandoahBarrierSetC2::verify_gc_barriers(Compile* compile, CompilePhase phase) const {
981 if (ShenandoahVerifyOptoBarriers && phase == BarrierSetC2::BeforeMacroExpand) {
982 ShenandoahBarrierC2Support::verify(Compile::current()->root());
983 } else if (phase == BarrierSetC2::BeforeCodeGen) {
984 // Verify G1 pre-barriers
985 const int marking_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset());
986
987 ResourceArea *area = Thread::current()->resource_area();
988 Unique_Node_List visited(area);
989 Node_List worklist(area);
990 // We're going to walk control flow backwards starting from the Root
991 worklist.push(compile->root());
992 while (worklist.size() > 0) {
993 Node *x = worklist.pop();
994 if (x == NULL || x == compile->top()) continue;
995 if (visited.member(x)) {
996 continue;
997 } else {
998 visited.push(x);
999 }
1000
1001 if (x->is_Region()) {
1002 for (uint i = 1; i < x->req(); i++) {
1003 worklist.push(x->in(i));
1004 }
1005 } else {
1006 worklist.push(x->in(0));
1007 // We are looking for the pattern:
1008 // /->ThreadLocal
1009 // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
1010 // \->ConI(0)
1011 // We want to verify that the If and the LoadB have the same control
1012 // See GraphKit::g1_write_barrier_pre()
1013 if (x->is_If()) {
1014 IfNode *iff = x->as_If();
1015 if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
1016 CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
1017 if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
1018 && cmp->in(1)->is_Load()) {
1019 LoadNode *load = cmp->in(1)->as_Load();
1020 if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
1021 && load->in(2)->in(3)->is_Con()
1022 && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
1023
1024 Node *if_ctrl = iff->in(0);
1025 Node *load_ctrl = load->in(0);
1026
1027 if (if_ctrl != load_ctrl) {
1028 // Skip possible CProj->NeverBranch in infinite loops
1029 if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
1030 && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
1031 if_ctrl = if_ctrl->in(0)->in(0);
1032 }
1033 }
1034 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
1035 }
1036 }
1037 }
1038 }
1039 }
1040 }
1041 }
1042 }
1043 #endif
1044
1045 Node* ShenandoahBarrierSetC2::ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const {
1046 if (is_shenandoah_wb_pre_call(n)) {
1047 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1048 if (n->req() > cnt) {
1049 Node* addp = n->in(cnt);
1050 if (has_only_shenandoah_wb_pre_uses(addp)) {
1051 n->del_req(cnt);
1052 if (can_reshape) {
1053 phase->is_IterGVN()->_worklist.push(addp);
1054 }
1055 return n;
1056 }
1057 }
1058 }
1059 if (n->Opcode() == Op_CmpP) {
1060 Node* in1 = n->in(1);
1061 Node* in2 = n->in(2);
1062 if (in1->bottom_type() == TypePtr::NULL_PTR) {
1063 in2 = step_over_gc_barrier(in2);
1064 }
1065 if (in2->bottom_type() == TypePtr::NULL_PTR) {
1066 in1 = step_over_gc_barrier(in1);
1067 }
1068 PhaseIterGVN* igvn = phase->is_IterGVN();
1069 if (in1 != n->in(1)) {
1070 if (igvn != NULL) {
1071 n->set_req_X(1, in1, igvn);
1072 } else {
1073 n->set_req(1, in1);
1074 }
1075 assert(in2 == n->in(2), "only one change");
1076 return n;
1077 }
1078 if (in2 != n->in(2)) {
1079 if (igvn != NULL) {
1080 n->set_req_X(2, in2, igvn);
1081 } else {
1082 n->set_req(2, in2);
1083 }
1084 return n;
1085 }
1086 } else if (can_reshape &&
1087 n->Opcode() == Op_If &&
1088 ShenandoahBarrierC2Support::is_heap_stable_test(n) &&
1089 n->in(0) != NULL) {
1090 Node* dom = n->in(0);
1091 Node* prev_dom = n;
1092 int op = n->Opcode();
1093 int dist = 16;
1094 // Search up the dominator tree for another heap stable test
1095 while (dom->Opcode() != op || // Not same opcode?
1096 !ShenandoahBarrierC2Support::is_heap_stable_test(dom) || // Not same input 1?
1097 prev_dom->in(0) != dom) { // One path of test does not dominate?
1098 if (dist < 0) return NULL;
1099
1100 dist--;
1101 prev_dom = dom;
1102 dom = IfNode::up_one_dom(dom);
1103 if (!dom) return NULL;
1104 }
1105
1106 // Check that we did not follow a loop back to ourselves
1107 if (n == dom) {
1108 return NULL;
1109 }
1110
1111 return n->as_If()->dominated_by(prev_dom, phase->is_IterGVN());
1112 }
1113
1114 return NULL;
1115 }
1116
1117 bool ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(Node* n) {
1118 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1119 Node* u = n->fast_out(i);
1120 if (!is_shenandoah_wb_pre_call(u)) {
1121 return false;
1122 }
1123 }
1124 return n->outcnt() > 0;
1125 }
1126
1127 bool ShenandoahBarrierSetC2::final_graph_reshaping(Compile* compile, Node* n, uint opcode) const {
1128 switch (opcode) {
1129 case Op_CallLeaf:
1130 case Op_CallLeafNoFP: {
1131 assert (n->is_Call(), "");
1132 CallNode *call = n->as_Call();
1133 if (ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(call)) {
1134 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1135 if (call->req() > cnt) {
1136 assert(call->req() == cnt + 1, "only one extra input");
1137 Node *addp = call->in(cnt);
1138 assert(!ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(addp), "useless address computation?");
1139 call->del_req(cnt);
1140 }
1141 }
1142 return false;
1143 }
1144 case Op_ShenandoahCompareAndSwapP:
1145 case Op_ShenandoahCompareAndSwapN:
1146 case Op_ShenandoahWeakCompareAndSwapN:
1147 case Op_ShenandoahWeakCompareAndSwapP:
1148 case Op_ShenandoahCompareAndExchangeP:
1149 case Op_ShenandoahCompareAndExchangeN:
1150 #ifdef ASSERT
1151 if( VerifyOptoOopOffsets ) {
1152 MemNode* mem = n->as_Mem();
1153 // Check to see if address types have grounded out somehow.
1154 const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
1155 ciInstanceKlass *k = tp->klass()->as_instance_klass();
1156 bool oop_offset_is_sane = k->contains_field_offset(tp->offset());
1157 assert( !tp || oop_offset_is_sane, "" );
1158 }
1159 #endif
1160 return true;
1161 case Op_ShenandoahLoadReferenceBarrier:
1162 assert(false, "should have been expanded already");
1163 return true;
1164 default:
1165 return false;
1166 }
1167 }
1168
1169 bool ShenandoahBarrierSetC2::escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const {
1170 switch (opcode) {
1171 case Op_ShenandoahCompareAndExchangeP:
1172 case Op_ShenandoahCompareAndExchangeN:
1173 conn_graph->add_objload_to_connection_graph(n, delayed_worklist);
1174 // fallthrough
1175 case Op_ShenandoahWeakCompareAndSwapP:
1176 case Op_ShenandoahWeakCompareAndSwapN:
1177 case Op_ShenandoahCompareAndSwapP:
1178 case Op_ShenandoahCompareAndSwapN:
1179 conn_graph->add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1180 return true;
1181 case Op_StoreP: {
1182 Node* adr = n->in(MemNode::Address);
1183 const Type* adr_type = gvn->type(adr);
1184 // Pointer stores in G1 barriers looks like unsafe access.
1185 // Ignore such stores to be able scalar replace non-escaping
1186 // allocations.
1187 if (adr_type->isa_rawptr() && adr->is_AddP()) {
1188 Node* base = conn_graph->get_addp_base(adr);
1189 if (base->Opcode() == Op_LoadP &&
1190 base->in(MemNode::Address)->is_AddP()) {
1191 adr = base->in(MemNode::Address);
1192 Node* tls = conn_graph->get_addp_base(adr);
1193 if (tls->Opcode() == Op_ThreadLocal) {
1194 int offs = (int) gvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1195 const int buf_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
1196 if (offs == buf_offset) {
1197 return true; // Pre barrier previous oop value store.
1198 }
1199 }
1200 }
1201 }
1202 return false;
1203 }
1204 case Op_ShenandoahEnqueueBarrier:
1205 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1206 break;
1207 case Op_ShenandoahLoadReferenceBarrier:
1208 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), delayed_worklist);
1209 return true;
1210 default:
1211 // Nothing
1212 break;
1213 }
1214 return false;
1215 }
1216
1217 bool ShenandoahBarrierSetC2::escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const {
1218 switch (opcode) {
1219 case Op_ShenandoahCompareAndExchangeP:
1220 case Op_ShenandoahCompareAndExchangeN: {
1221 Node *adr = n->in(MemNode::Address);
1222 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
1223 // fallthrough
1224 }
1225 case Op_ShenandoahCompareAndSwapP:
1226 case Op_ShenandoahCompareAndSwapN:
1227 case Op_ShenandoahWeakCompareAndSwapP:
1228 case Op_ShenandoahWeakCompareAndSwapN:
1229 return conn_graph->add_final_edges_unsafe_access(n, opcode);
1230 case Op_ShenandoahEnqueueBarrier:
1231 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), NULL);
1232 return true;
1233 case Op_ShenandoahLoadReferenceBarrier:
1234 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), NULL);
1235 return true;
1236 default:
1237 // Nothing
1238 break;
1239 }
1240 return false;
1241 }
1242
1243 bool ShenandoahBarrierSetC2::escape_has_out_with_unsafe_object(Node* n) const {
1244 return n->has_out_with(Op_ShenandoahCompareAndExchangeP) || n->has_out_with(Op_ShenandoahCompareAndExchangeN) ||
1245 n->has_out_with(Op_ShenandoahCompareAndSwapP, Op_ShenandoahCompareAndSwapN, Op_ShenandoahWeakCompareAndSwapP, Op_ShenandoahWeakCompareAndSwapN);
1246
1247 }
1248
1249 bool ShenandoahBarrierSetC2::matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const {
1250 switch (opcode) {
1251 case Op_ShenandoahCompareAndExchangeP:
1252 case Op_ShenandoahCompareAndExchangeN:
1253 case Op_ShenandoahWeakCompareAndSwapP:
1254 case Op_ShenandoahWeakCompareAndSwapN:
1255 case Op_ShenandoahCompareAndSwapP:
1256 case Op_ShenandoahCompareAndSwapN: { // Convert trinary to binary-tree
1257 Node* newval = n->in(MemNode::ValueIn);
1258 Node* oldval = n->in(LoadStoreConditionalNode::ExpectedIn);
1259 Node* pair = new BinaryNode(oldval, newval);
1260 n->set_req(MemNode::ValueIn,pair);
1261 n->del_req(LoadStoreConditionalNode::ExpectedIn);
1262 return true;
1263 }
1264 default:
1265 break;
1266 }
1267 return false;
1268 }
1269
1270 bool ShenandoahBarrierSetC2::matcher_is_store_load_barrier(Node* x, uint xop) const {
1271 return xop == Op_ShenandoahCompareAndExchangeP ||
1272 xop == Op_ShenandoahCompareAndExchangeN ||
1273 xop == Op_ShenandoahWeakCompareAndSwapP ||
1274 xop == Op_ShenandoahWeakCompareAndSwapN ||
1275 xop == Op_ShenandoahCompareAndSwapN ||
1276 xop == Op_ShenandoahCompareAndSwapP;
1277 }