16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.hpp"
30 #include "gc/shenandoah/shenandoahHeap.hpp"
31 #include "gc/shenandoah/shenandoahRuntime.hpp"
32 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
33 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
34 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
35 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
36 #include "opto/arraycopynode.hpp"
37 #include "opto/escape.hpp"
38 #include "opto/graphKit.hpp"
39 #include "opto/idealKit.hpp"
40 #include "opto/macro.hpp"
41 #include "opto/movenode.hpp"
42 #include "opto/narrowptrnode.hpp"
43 #include "opto/rootnode.hpp"
44 #include "opto/runtime.hpp"
45
46 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
47 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
48 }
49
50 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
51 : _iu_barriers(new (comp_arena) GrowableArray<ShenandoahIUBarrierNode*>(comp_arena, 8, 0, NULL)),
52 _load_reference_barriers(new (comp_arena) GrowableArray<ShenandoahLoadReferenceBarrierNode*>(comp_arena, 8, 0, NULL)) {
53 }
54
55 int ShenandoahBarrierSetC2State::iu_barriers_count() const {
224
225 Node* no_base = __ top();
226 Node* zero = __ ConI(0);
227 Node* zeroX = __ ConX(0);
228
229 float likely = PROB_LIKELY(0.999);
230 float unlikely = PROB_UNLIKELY(0.999);
231
232 // Offsets into the thread
233 const int index_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset());
234 const int buffer_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
235
236 // Now the actual pointers into the thread
237 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
238 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
239
240 // Now some of the values
241 Node* marking;
242 Node* gc_state = __ AddP(no_base, tls, __ ConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset())));
243 Node* ld = __ load(__ ctrl(), gc_state, TypeInt::BYTE, T_BYTE, Compile::AliasIdxRaw);
244 marking = __ AndI(ld, __ ConI(ShenandoahHeap::MARKING));
245 assert(ShenandoahBarrierC2Support::is_gc_state_load(ld), "Should match the shape");
246
247 // if (!marking)
248 __ if_then(marking, BoolTest::ne, zero, unlikely); {
249 BasicType index_bt = TypeX_X->basic_type();
250 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading Shenandoah SATBMarkQueue::_index with wrong size.");
251 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
252
253 if (do_load) {
254 // load original value
255 // alias_idx correct??
256 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
257 }
258
259 // if (pre_val != NULL)
260 __ if_then(pre_val, BoolTest::ne, kit->null()); {
261 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
262
263 // is the queue for this thread full?
264 __ if_then(index, BoolTest::ne, zeroX, likely); {
305 address entry_point = call->as_CallLeaf()->entry_point();
306 return (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong)) ||
307 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow)) ||
308 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak)) ||
309 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow)) ||
310 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom));
311 }
312
313 bool ShenandoahBarrierSetC2::is_shenandoah_marking_if(PhaseTransform *phase, Node* n) {
314 if (n->Opcode() != Op_If) {
315 return false;
316 }
317
318 Node* bol = n->in(1);
319 assert(bol->is_Bool(), "");
320 Node* cmpx = bol->in(1);
321 if (bol->as_Bool()->_test._test == BoolTest::ne &&
322 cmpx->is_Cmp() && cmpx->in(2) == phase->intcon(0) &&
323 is_shenandoah_state_load(cmpx->in(1)->in(1)) &&
324 cmpx->in(1)->in(2)->is_Con() &&
325 cmpx->in(1)->in(2) == phase->intcon(ShenandoahHeap::MARKING)) {
326 return true;
327 }
328
329 return false;
330 }
331
332 bool ShenandoahBarrierSetC2::is_shenandoah_state_load(Node* n) {
333 if (!n->is_Load()) return false;
334 const int state_offset = in_bytes(ShenandoahThreadLocalData::gc_state_offset());
335 return n->in(2)->is_AddP() && n->in(2)->in(2)->Opcode() == Op_ThreadLocal
336 && n->in(2)->in(3)->is_Con()
337 && n->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == state_offset;
338 }
339
340 void ShenandoahBarrierSetC2::shenandoah_write_barrier_pre(GraphKit* kit,
341 bool do_load,
342 Node* obj,
343 Node* adr,
344 uint alias_idx,
345 Node* val,
434 // Use the pre-barrier to record the value in the referent field
435 satb_write_barrier_pre(kit, false /* do_load */,
436 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
437 pre_val /* pre_val */,
438 T_OBJECT);
439 if (need_mem_bar) {
440 // Add memory barrier to prevent commoning reads from this field
441 // across safepoint since GC can change its value.
442 kit->insert_mem_bar(Op_MemBarCPUOrder);
443 }
444 // Update IdealKit from graphKit.
445 __ sync_kit(kit);
446
447 } __ end_if(); // _ref_type != ref_none
448 } __ end_if(); // offset == referent_offset
449
450 // Final sync IdealKit and GraphKit.
451 kit->final_sync(ideal);
452 }
453
454 #undef __
455
456 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
457 const Type **fields = TypeTuple::fields(2);
458 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
459 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
460 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
461
462 // create result type (range)
463 fields = TypeTuple::fields(0);
464 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
465
466 return TypeFunc::make(domain, range);
467 }
468
469 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
470 const Type **fields = TypeTuple::fields(1);
471 fields[TypeFunc::Parms+0] = TypeOopPtr::NOTNULL; // src oop
472 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
473
500 Node* adr = access.addr().node();
501
502 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
503 bool on_heap = (decorators & IN_HEAP) != 0;
504
505 if (!access.is_oop() || (!on_heap && !anonymous)) {
506 return BarrierSetC2::store_at_resolved(access, val);
507 }
508
509 if (access.is_parse_access()) {
510 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
511 GraphKit* kit = parse_access.kit();
512
513 uint adr_idx = kit->C->get_alias_index(adr_type);
514 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
515 Node* value = val.node();
516 value = shenandoah_iu_barrier(kit, value);
517 val.set_node(value);
518 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
519 static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
520 } else {
521 assert(access.is_opt_access(), "only for optimization passes");
522 assert(((decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0 || !ShenandoahSATBBarrier) && (decorators & C2_ARRAY_COPY) != 0, "unexpected caller of this code");
523 C2OptAccess& opt_access = static_cast<C2OptAccess&>(access);
524 PhaseGVN& gvn = opt_access.gvn();
525
526 if (ShenandoahIUBarrier) {
527 Node* enqueue = gvn.transform(new ShenandoahIUBarrierNode(val.node()));
528 val.set_node(enqueue);
529 }
530 }
531 return BarrierSetC2::store_at_resolved(access, val);
532 }
533
534 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
535 // 1: non-reference load, no additional barrier is needed
536 if (!access.is_oop()) {
537 return BarrierSetC2::load_at_resolved(access, val_type);;
538 }
539
540 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
541 DecoratorSet decorators = access.decorators();
542 BasicType type = access.type();
543
544 // 2: apply LRB if needed
545 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
546 load = new ShenandoahLoadReferenceBarrierNode(NULL, load, decorators);
547 if (access.is_parse_access()) {
548 load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
549 } else {
550 load = static_cast<C2OptAccess &>(access).gvn().transform(load);
551 }
582
583 if (on_weak_ref) {
584 // Use the pre-barrier to record the value in the referent field
585 satb_write_barrier_pre(kit, false /* do_load */,
586 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
587 load /* pre_val */, T_OBJECT);
588 // Add memory barrier to prevent commoning reads from this field
589 // across safepoint since GC can change its value.
590 kit->insert_mem_bar(Op_MemBarCPUOrder);
591 } else if (unknown) {
592 // We do not require a mem bar inside pre_barrier if need_mem_bar
593 // is set: the barriers would be emitted by us.
594 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
595 }
596 }
597
598 return load;
599 }
600
601 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
602 Node* new_val, const Type* value_type) const {
603 GraphKit* kit = access.kit();
604 if (access.is_oop()) {
605 new_val = shenandoah_iu_barrier(kit, new_val);
606 shenandoah_write_barrier_pre(kit, false /* do_load */,
607 NULL, NULL, max_juint, NULL, NULL,
608 expected_val /* pre_val */, T_OBJECT);
609
610 MemNode::MemOrd mo = access.mem_node_mo();
611 Node* mem = access.memory();
612 Node* adr = access.addr().node();
613 const TypePtr* adr_type = access.addr().type();
614 Node* load_store = NULL;
615
616 #ifdef _LP64
617 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
618 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
619 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
620 if (ShenandoahCASBarrier) {
621 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
622 } else {
624 }
625 } else
626 #endif
627 {
628 if (ShenandoahCASBarrier) {
629 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
630 } else {
631 load_store = kit->gvn().transform(new CompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
632 }
633 }
634
635 access.set_raw_access(load_store);
636 pin_atomic_op(access);
637
638 #ifdef _LP64
639 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
640 load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
641 }
642 #endif
643 load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, load_store, access.decorators()));
644 return load_store;
645 }
646 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
647 }
648
649 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
650 Node* new_val, const Type* value_type) const {
651 GraphKit* kit = access.kit();
652 if (access.is_oop()) {
653 new_val = shenandoah_iu_barrier(kit, new_val);
654 shenandoah_write_barrier_pre(kit, false /* do_load */,
655 NULL, NULL, max_juint, NULL, NULL,
656 expected_val /* pre_val */, T_OBJECT);
657 DecoratorSet decorators = access.decorators();
658 MemNode::MemOrd mo = access.mem_node_mo();
659 Node* mem = access.memory();
660 bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
661 Node* load_store = NULL;
662 Node* adr = access.addr().node();
663 #ifdef _LP64
679 }
680 } else
681 #endif
682 {
683 if (ShenandoahCASBarrier) {
684 if (is_weak_cas) {
685 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
686 } else {
687 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
688 }
689 } else {
690 if (is_weak_cas) {
691 load_store = kit->gvn().transform(new WeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
692 } else {
693 load_store = kit->gvn().transform(new CompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
694 }
695 }
696 }
697 access.set_raw_access(load_store);
698 pin_atomic_op(access);
699 return load_store;
700 }
701 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
702 }
703
704 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* val, const Type* value_type) const {
705 GraphKit* kit = access.kit();
706 if (access.is_oop()) {
707 val = shenandoah_iu_barrier(kit, val);
708 }
709 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
710 if (access.is_oop()) {
711 result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, result, access.decorators()));
712 shenandoah_write_barrier_pre(kit, false /* do_load */,
713 NULL, NULL, max_juint, NULL, NULL,
714 result /* pre_val */, T_OBJECT);
715 }
716 return result;
717 }
718
719 // Support for GC barriers emitted during parsing
720 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
721 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) return true;
722 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
723 return false;
724 }
725 CallLeafNode *call = node->as_CallLeaf();
726 if (call->_name == NULL) {
727 return false;
728 }
729
730 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
731 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
732 strcmp(call->_name, "shenandoah_wb_pre") == 0;
733 }
734
777 if (phase == Optimization) {
778 return !ShenandoahIUBarrier;
779 }
780 return true;
781 }
782
783 bool ShenandoahBarrierSetC2::clone_needs_barrier(Node* src, PhaseGVN& gvn) {
784 const TypeOopPtr* src_type = gvn.type(src)->is_oopptr();
785 if (src_type->isa_instptr() != NULL) {
786 ciInstanceKlass* ik = src_type->klass()->as_instance_klass();
787 if ((src_type->klass_is_exact() || (!ik->is_interface() && !ik->has_subklass())) && !ik->has_injected_fields()) {
788 if (ik->has_object_fields()) {
789 return true;
790 } else {
791 if (!src_type->klass_is_exact()) {
792 Compile::current()->dependencies()->assert_leaf_type(ik);
793 }
794 }
795 } else {
796 return true;
797 }
798 } else if (src_type->isa_aryptr()) {
799 BasicType src_elem = src_type->klass()->as_array_klass()->element_type()->basic_type();
800 if (is_reference_type(src_elem)) {
801 return true;
802 }
803 } else {
804 return true;
805 }
806 return false;
807 }
808
809 void ShenandoahBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
810 Node* ctrl = ac->in(TypeFunc::Control);
811 Node* mem = ac->in(TypeFunc::Memory);
812 Node* src_base = ac->in(ArrayCopyNode::Src);
813 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
814 Node* dest_base = ac->in(ArrayCopyNode::Dest);
815 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
816 Node* length = ac->in(ArrayCopyNode::Length);
817
820
821 if (ShenandoahCloneBarrier && clone_needs_barrier(src, phase->igvn())) {
822 // Check if heap is has forwarded objects. If it does, we need to call into the special
823 // routine that would fix up source references before we can continue.
824
825 enum { _heap_stable = 1, _heap_unstable, PATH_LIMIT };
826 Node* region = new RegionNode(PATH_LIMIT);
827 Node* mem_phi = new PhiNode(region, Type::MEMORY, TypeRawPtr::BOTTOM);
828
829 Node* thread = phase->transform_later(new ThreadLocalNode());
830 Node* offset = phase->igvn().MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
831 Node* gc_state_addr = phase->transform_later(new AddPNode(phase->C->top(), thread, offset));
832
833 uint gc_state_idx = Compile::AliasIdxRaw;
834 const TypePtr* gc_state_adr_type = NULL; // debug-mode-only argument
835 debug_only(gc_state_adr_type = phase->C->get_adr_type(gc_state_idx));
836
837 Node* gc_state = phase->transform_later(new LoadBNode(ctrl, mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered));
838 int flags = ShenandoahHeap::HAS_FORWARDED;
839 if (ShenandoahIUBarrier) {
840 flags |= ShenandoahHeap::MARKING;
841 }
842 Node* stable_and = phase->transform_later(new AndINode(gc_state, phase->igvn().intcon(flags)));
843 Node* stable_cmp = phase->transform_later(new CmpINode(stable_and, phase->igvn().zerocon(T_INT)));
844 Node* stable_test = phase->transform_later(new BoolNode(stable_cmp, BoolTest::ne));
845
846 IfNode* stable_iff = phase->transform_later(new IfNode(ctrl, stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN))->as_If();
847 Node* stable_ctrl = phase->transform_later(new IfFalseNode(stable_iff));
848 Node* unstable_ctrl = phase->transform_later(new IfTrueNode(stable_iff));
849
850 // Heap is stable, no need to do anything additional
851 region->init_req(_heap_stable, stable_ctrl);
852 mem_phi->init_req(_heap_stable, mem);
853
854 // Heap is unstable, call into clone barrier stub
855 Node* call = phase->make_leaf_call(unstable_ctrl, mem,
856 ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type(),
857 CAST_FROM_FN_PTR(address, ShenandoahRuntime::shenandoah_clone_barrier),
858 "shenandoah_clone",
859 TypeRawPtr::BOTTOM,
860 src_base);
888
889 // Support for macro expanded GC barriers
890 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
891 if (node->Opcode() == Op_ShenandoahIUBarrier) {
892 state()->add_iu_barrier((ShenandoahIUBarrierNode*) node);
893 }
894 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
895 state()->add_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
896 }
897 }
898
899 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
900 if (node->Opcode() == Op_ShenandoahIUBarrier) {
901 state()->remove_iu_barrier((ShenandoahIUBarrierNode*) node);
902 }
903 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
904 state()->remove_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
905 }
906 }
907
908 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* n) const {
909 if (is_shenandoah_wb_pre_call(n)) {
910 shenandoah_eliminate_wb_pre(n, ¯o->igvn());
911 }
912 }
913
914 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
915 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
916 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
917 c = c->unique_ctrl_out();
918 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
919 c = c->unique_ctrl_out();
920 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
921 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
922 assert(iff->is_If(), "expect test");
923 if (!is_shenandoah_marking_if(igvn, iff)) {
924 c = c->unique_ctrl_out();
925 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
926 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
927 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
928 }
929 Node* cmpx = iff->in(1)->in(1);
930 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
|
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.hpp"
30 #include "gc/shenandoah/shenandoahHeap.hpp"
31 #include "gc/shenandoah/shenandoahRuntime.hpp"
32 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
33 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
34 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
35 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
36 #include "gc/shenandoah/mode/shenandoahMode.hpp"
37 #include "opto/arraycopynode.hpp"
38 #include "opto/escape.hpp"
39 #include "opto/graphKit.hpp"
40 #include "opto/idealKit.hpp"
41 #include "opto/macro.hpp"
42 #include "opto/movenode.hpp"
43 #include "opto/narrowptrnode.hpp"
44 #include "opto/rootnode.hpp"
45 #include "opto/runtime.hpp"
46
47 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
48 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
49 }
50
51 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
52 : _iu_barriers(new (comp_arena) GrowableArray<ShenandoahIUBarrierNode*>(comp_arena, 8, 0, NULL)),
53 _load_reference_barriers(new (comp_arena) GrowableArray<ShenandoahLoadReferenceBarrierNode*>(comp_arena, 8, 0, NULL)) {
54 }
55
56 int ShenandoahBarrierSetC2State::iu_barriers_count() const {
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::YOUNG_MARKING | ShenandoahHeap::OLD_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 != 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); {
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(PhaseTransform *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::YOUNG_MARKING | ShenandoahHeap::OLD_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,
435 // Use the pre-barrier to record the value in the referent field
436 satb_write_barrier_pre(kit, false /* do_load */,
437 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* 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 != NULL) {
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 if (!ShenandoahHeap::heap()->mode()->is_generational()) {
476 return;
477 }
478
479 ShenandoahBarrierSet* ctbs = barrier_set_cast<ShenandoahBarrierSet>(BarrierSet::barrier_set());
480 CardTable* ct = ctbs->card_table();
481 // No store check needed if we're storing a NULL or an old object
482 // (latter case is probably a string constant). The concurrent
483 // mark sweep garbage collector, however, needs to have all nonNull
484 // oop updates flagged via card-marks.
485 if (val != NULL && val->is_Con()) {
486 // must be either an oop or NULL
487 const Type* t = val->bottom_type();
488 if (t == TypePtr::NULL_PTR || t == Type::TOP)
489 // stores of null never (?) need barriers
490 return;
491 }
492
493 if (ReduceInitialCardMarks && obj == kit->just_allocated_object(kit->control())) {
494 // We can skip marks on a freshly-allocated object in Eden.
495 // Keep this code in sync with new_deferred_store_barrier() in runtime.cpp.
496 // That routine informs GC to take appropriate compensating steps,
497 // upon a slow-path allocation, so as to make this card-mark
498 // elision safe.
499 return;
500 }
501
502 if (!use_precise) {
503 // All card marks for a (non-array) instance are in one place:
504 adr = obj;
505 }
506 // (Else it's an array (or unknown), and we want more precise card marks.)
507 assert(adr != NULL, "");
508
509 IdealKit ideal(kit, true);
510
511 // Convert the pointer to an int prior to doing math on it
512 Node* cast = __ CastPX(__ ctrl(), adr);
513
514 // Divide by card size
515 Node* card_offset = __ URShiftX( cast, __ ConI(CardTable::card_shift) );
516
517 // Combine card table base and card offset
518 Node* card_adr = __ AddP(__ top(), byte_map_base_node(kit), card_offset );
519
520 // Get the alias_index for raw card-mark memory
521 int adr_type = Compile::AliasIdxRaw;
522 Node* zero = __ ConI(0); // Dirty card value
523
524 if (UseCondCardMark) {
525 // The classic GC reference write barrier is typically implemented
526 // as a store into the global card mark table. Unfortunately
527 // unconditional stores can result in false sharing and excessive
528 // coherence traffic as well as false transactional aborts.
529 // UseCondCardMark enables MP "polite" conditional card mark
530 // stores. In theory we could relax the load from ctrl() to
531 // no_ctrl, but that doesn't buy much latitude.
532 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, T_BYTE, adr_type);
533 __ if_then(card_val, BoolTest::ne, zero);
534 }
535
536 // Smash zero into card
537 __ store(__ ctrl(), card_adr, zero, T_BYTE, adr_type, MemNode::unordered);
538
539 if (UseCondCardMark) {
540 __ end_if();
541 }
542
543 // Final sync IdealKit and GraphKit.
544 kit->final_sync(ideal);
545 }
546
547 #undef __
548
549 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
550 const Type **fields = TypeTuple::fields(2);
551 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
552 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
553 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
554
555 // create result type (range)
556 fields = TypeTuple::fields(0);
557 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
558
559 return TypeFunc::make(domain, range);
560 }
561
562 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
563 const Type **fields = TypeTuple::fields(1);
564 fields[TypeFunc::Parms+0] = TypeOopPtr::NOTNULL; // src oop
565 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
566
593 Node* adr = access.addr().node();
594
595 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
596 bool on_heap = (decorators & IN_HEAP) != 0;
597
598 if (!access.is_oop() || (!on_heap && !anonymous)) {
599 return BarrierSetC2::store_at_resolved(access, val);
600 }
601
602 if (access.is_parse_access()) {
603 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
604 GraphKit* kit = parse_access.kit();
605
606 uint adr_idx = kit->C->get_alias_index(adr_type);
607 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
608 Node* value = val.node();
609 value = shenandoah_iu_barrier(kit, value);
610 val.set_node(value);
611 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
612 static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
613
614 Node* result = BarrierSetC2::store_at_resolved(access, val);
615 bool is_array = (decorators & IS_ARRAY) != 0;
616 bool use_precise = is_array || anonymous;
617 post_barrier(kit, kit->control(), access.raw_access(), access.base(), adr, adr_idx, val.node(), access.type(), use_precise);
618 return result;
619 } else {
620 assert(access.is_opt_access(), "only for optimization passes");
621 assert(((decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0 || !ShenandoahSATBBarrier) && (decorators & C2_ARRAY_COPY) != 0, "unexpected caller of this code");
622 C2OptAccess& opt_access = static_cast<C2OptAccess&>(access);
623 PhaseGVN& gvn = opt_access.gvn();
624
625 if (ShenandoahIUBarrier) {
626 Node* enqueue = gvn.transform(new ShenandoahIUBarrierNode(val.node()));
627 val.set_node(enqueue);
628 }
629 return BarrierSetC2::store_at_resolved(access, val);
630 }
631 }
632
633 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
634 // 1: non-reference load, no additional barrier is needed
635 if (!access.is_oop()) {
636 return BarrierSetC2::load_at_resolved(access, val_type);;
637 }
638
639 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
640 DecoratorSet decorators = access.decorators();
641 BasicType type = access.type();
642
643 // 2: apply LRB if needed
644 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
645 load = new ShenandoahLoadReferenceBarrierNode(NULL, load, decorators);
646 if (access.is_parse_access()) {
647 load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
648 } else {
649 load = static_cast<C2OptAccess &>(access).gvn().transform(load);
650 }
681
682 if (on_weak_ref) {
683 // Use the pre-barrier to record the value in the referent field
684 satb_write_barrier_pre(kit, false /* do_load */,
685 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
686 load /* pre_val */, T_OBJECT);
687 // Add memory barrier to prevent commoning reads from this field
688 // across safepoint since GC can change its value.
689 kit->insert_mem_bar(Op_MemBarCPUOrder);
690 } else if (unknown) {
691 // We do not require a mem bar inside pre_barrier if need_mem_bar
692 // is set: the barriers would be emitted by us.
693 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
694 }
695 }
696
697 return load;
698 }
699
700 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
701 Node* new_val, const Type* value_type) const {
702 GraphKit* kit = access.kit();
703 if (access.is_oop()) {
704 new_val = shenandoah_iu_barrier(kit, new_val);
705 shenandoah_write_barrier_pre(kit, false /* do_load */,
706 NULL, NULL, max_juint, NULL, NULL,
707 expected_val /* pre_val */, T_OBJECT);
708
709 MemNode::MemOrd mo = access.mem_node_mo();
710 Node* mem = access.memory();
711 Node* adr = access.addr().node();
712 const TypePtr* adr_type = access.addr().type();
713 Node* load_store = NULL;
714
715 #ifdef _LP64
716 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
717 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
718 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
719 if (ShenandoahCASBarrier) {
720 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
721 } else {
723 }
724 } else
725 #endif
726 {
727 if (ShenandoahCASBarrier) {
728 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
729 } else {
730 load_store = kit->gvn().transform(new CompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
731 }
732 }
733
734 access.set_raw_access(load_store);
735 pin_atomic_op(access);
736
737 #ifdef _LP64
738 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
739 load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
740 }
741 #endif
742 load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, load_store, access.decorators()));
743 post_barrier(kit, kit->control(), access.raw_access(), access.base(), access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
744 return load_store;
745 }
746 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
747 }
748
749 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
750 Node* new_val, const Type* value_type) const {
751 GraphKit* kit = access.kit();
752 if (access.is_oop()) {
753 new_val = shenandoah_iu_barrier(kit, new_val);
754 shenandoah_write_barrier_pre(kit, false /* do_load */,
755 NULL, NULL, max_juint, NULL, NULL,
756 expected_val /* pre_val */, T_OBJECT);
757 DecoratorSet decorators = access.decorators();
758 MemNode::MemOrd mo = access.mem_node_mo();
759 Node* mem = access.memory();
760 bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
761 Node* load_store = NULL;
762 Node* adr = access.addr().node();
763 #ifdef _LP64
779 }
780 } else
781 #endif
782 {
783 if (ShenandoahCASBarrier) {
784 if (is_weak_cas) {
785 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
786 } else {
787 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
788 }
789 } else {
790 if (is_weak_cas) {
791 load_store = kit->gvn().transform(new WeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
792 } else {
793 load_store = kit->gvn().transform(new CompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
794 }
795 }
796 }
797 access.set_raw_access(load_store);
798 pin_atomic_op(access);
799 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
800 access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
801 return load_store;
802 }
803 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
804 }
805
806 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* val, const Type* value_type) const {
807 GraphKit* kit = access.kit();
808 if (access.is_oop()) {
809 val = shenandoah_iu_barrier(kit, val);
810 }
811 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
812 if (access.is_oop()) {
813 result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, result, access.decorators()));
814 shenandoah_write_barrier_pre(kit, false /* do_load */,
815 NULL, NULL, max_juint, NULL, NULL,
816 result /* pre_val */, T_OBJECT);
817 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
818 access.addr().node(), access.alias_idx(), val, T_OBJECT, true);
819 }
820 return result;
821 }
822
823 // Support for GC barriers emitted during parsing
824 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
825 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) return true;
826 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
827 return false;
828 }
829 CallLeafNode *call = node->as_CallLeaf();
830 if (call->_name == NULL) {
831 return false;
832 }
833
834 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
835 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
836 strcmp(call->_name, "shenandoah_wb_pre") == 0;
837 }
838
881 if (phase == Optimization) {
882 return !ShenandoahIUBarrier;
883 }
884 return true;
885 }
886
887 bool ShenandoahBarrierSetC2::clone_needs_barrier(Node* src, PhaseGVN& gvn) {
888 const TypeOopPtr* src_type = gvn.type(src)->is_oopptr();
889 if (src_type->isa_instptr() != NULL) {
890 ciInstanceKlass* ik = src_type->klass()->as_instance_klass();
891 if ((src_type->klass_is_exact() || (!ik->is_interface() && !ik->has_subklass())) && !ik->has_injected_fields()) {
892 if (ik->has_object_fields()) {
893 return true;
894 } else {
895 if (!src_type->klass_is_exact()) {
896 Compile::current()->dependencies()->assert_leaf_type(ik);
897 }
898 }
899 } else {
900 return true;
901 }
902 } else if (src_type->isa_aryptr()) {
903 BasicType src_elem = src_type->klass()->as_array_klass()->element_type()->basic_type();
904 if (is_reference_type(src_elem)) {
905 return true;
906 }
907 } else {
908 return true;
909 }
910 return false;
911 }
912
913 void ShenandoahBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
914 Node* ctrl = ac->in(TypeFunc::Control);
915 Node* mem = ac->in(TypeFunc::Memory);
916 Node* src_base = ac->in(ArrayCopyNode::Src);
917 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
918 Node* dest_base = ac->in(ArrayCopyNode::Dest);
919 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
920 Node* length = ac->in(ArrayCopyNode::Length);
921
924
925 if (ShenandoahCloneBarrier && clone_needs_barrier(src, phase->igvn())) {
926 // Check if heap is has forwarded objects. If it does, we need to call into the special
927 // routine that would fix up source references before we can continue.
928
929 enum { _heap_stable = 1, _heap_unstable, PATH_LIMIT };
930 Node* region = new RegionNode(PATH_LIMIT);
931 Node* mem_phi = new PhiNode(region, Type::MEMORY, TypeRawPtr::BOTTOM);
932
933 Node* thread = phase->transform_later(new ThreadLocalNode());
934 Node* offset = phase->igvn().MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
935 Node* gc_state_addr = phase->transform_later(new AddPNode(phase->C->top(), thread, offset));
936
937 uint gc_state_idx = Compile::AliasIdxRaw;
938 const TypePtr* gc_state_adr_type = NULL; // debug-mode-only argument
939 debug_only(gc_state_adr_type = phase->C->get_adr_type(gc_state_idx));
940
941 Node* gc_state = phase->transform_later(new LoadBNode(ctrl, mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered));
942 int flags = ShenandoahHeap::HAS_FORWARDED;
943 if (ShenandoahIUBarrier) {
944 flags |= ShenandoahHeap::YOUNG_MARKING;
945 }
946 Node* stable_and = phase->transform_later(new AndINode(gc_state, phase->igvn().intcon(flags)));
947 Node* stable_cmp = phase->transform_later(new CmpINode(stable_and, phase->igvn().zerocon(T_INT)));
948 Node* stable_test = phase->transform_later(new BoolNode(stable_cmp, BoolTest::ne));
949
950 IfNode* stable_iff = phase->transform_later(new IfNode(ctrl, stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN))->as_If();
951 Node* stable_ctrl = phase->transform_later(new IfFalseNode(stable_iff));
952 Node* unstable_ctrl = phase->transform_later(new IfTrueNode(stable_iff));
953
954 // Heap is stable, no need to do anything additional
955 region->init_req(_heap_stable, stable_ctrl);
956 mem_phi->init_req(_heap_stable, mem);
957
958 // Heap is unstable, call into clone barrier stub
959 Node* call = phase->make_leaf_call(unstable_ctrl, mem,
960 ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type(),
961 CAST_FROM_FN_PTR(address, ShenandoahRuntime::shenandoah_clone_barrier),
962 "shenandoah_clone",
963 TypeRawPtr::BOTTOM,
964 src_base);
992
993 // Support for macro expanded GC barriers
994 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
995 if (node->Opcode() == Op_ShenandoahIUBarrier) {
996 state()->add_iu_barrier((ShenandoahIUBarrierNode*) node);
997 }
998 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
999 state()->add_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
1000 }
1001 }
1002
1003 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
1004 if (node->Opcode() == Op_ShenandoahIUBarrier) {
1005 state()->remove_iu_barrier((ShenandoahIUBarrierNode*) node);
1006 }
1007 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
1008 state()->remove_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
1009 }
1010 }
1011
1012 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const {
1013 if (is_shenandoah_wb_pre_call(node)) {
1014 shenandoah_eliminate_wb_pre(node, ¯o->igvn());
1015 }
1016 if (node->Opcode() == Op_CastP2X && ShenandoahHeap::heap()->mode()->is_generational()) {
1017 assert(node->Opcode() == Op_CastP2X, "ConvP2XNode required");
1018 Node *shift = node->unique_out();
1019 Node *addp = shift->unique_out();
1020 for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) {
1021 Node *mem = addp->last_out(j);
1022 if (UseCondCardMark && mem->is_Load()) {
1023 assert(mem->Opcode() == Op_LoadB, "unexpected code shape");
1024 // The load is checking if the card has been written so
1025 // replace it with zero to fold the test.
1026 macro->replace_node(mem, macro->intcon(0));
1027 continue;
1028 }
1029 assert(mem->is_Store(), "store required");
1030 macro->replace_node(mem, mem->in(MemNode::Memory));
1031 }
1032 }
1033 }
1034
1035 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
1036 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
1037 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
1038 c = c->unique_ctrl_out();
1039 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1040 c = c->unique_ctrl_out();
1041 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1042 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
1043 assert(iff->is_If(), "expect test");
1044 if (!is_shenandoah_marking_if(igvn, iff)) {
1045 c = c->unique_ctrl_out();
1046 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
1047 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
1048 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
1049 }
1050 Node* cmpx = iff->in(1)->in(1);
1051 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
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