24 */
25
26 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
27 #include "gc/shenandoah/mode/shenandoahMode.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
30 #include "gc/shenandoah/shenandoahForwarding.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
33 #include "gc/shenandoah/shenandoahRuntime.hpp"
34 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
35 #include "interpreter/interpreter.hpp"
36 #include "runtime/javaThread.hpp"
37 #include "runtime/sharedRuntime.hpp"
38 #include "utilities/macros.hpp"
39 #ifdef COMPILER1
40 #include "c1/c1_LIRAssembler.hpp"
41 #include "c1/c1_MacroAssembler.hpp"
42 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
43 #endif
44
45 #define __ masm->
46
47 static void save_machine_state(MacroAssembler* masm, bool handle_gpr, bool handle_fp) {
48 if (handle_gpr) {
49 __ push_IU_state();
50 }
51
52 if (handle_fp) {
53 // Some paths can be reached from the c2i adapter with live fp arguments in registers.
54 assert(Argument::n_float_register_parameters_j == 8, "8 fp registers to save at java call");
55
56 const int xmm_size = wordSize * 2;
57 __ subptr(rsp, xmm_size * 8);
58 __ movdbl(Address(rsp, xmm_size * 0), xmm0);
59 __ movdbl(Address(rsp, xmm_size * 1), xmm1);
60 __ movdbl(Address(rsp, xmm_size * 2), xmm2);
61 __ movdbl(Address(rsp, xmm_size * 3), xmm3);
62 __ movdbl(Address(rsp, xmm_size * 4), xmm4);
63 __ movdbl(Address(rsp, xmm_size * 5), xmm5);
655 if (UseCompressedOops) {
656 __ lock();
657 __ cmpxchgl(newval, addr);
658 } else {
659 __ lock();
660 __ cmpxchgptr(newval, addr);
661 }
662 __ jcc(Assembler::equal, L_success);
663
664 // Step 2. CAS had failed. This may be a false negative.
665 //
666 // The trouble comes when we compare the to-space pointer with the from-space
667 // pointer to the same object. To resolve this, it will suffice to resolve
668 // the value from memory -- this will give both to-space pointers.
669 // If they mismatch, then it was a legitimate failure.
670 //
671 // Before reaching to resolve sequence, see if we can avoid the whole shebang
672 // with filters.
673
674 // Filter: when offending in-memory value is null, the failure is definitely legitimate
675 __ testptr(oldval, oldval);
676 __ jcc(Assembler::zero, L_failure);
677
678 // Filter: when heap is stable, the failure is definitely legitimate
679 const Register thread = r15_thread;
680 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
681 __ testb(gc_state, ShenandoahHeap::HAS_FORWARDED);
682 __ jcc(Assembler::zero, L_failure);
683
684 if (UseCompressedOops) {
685 __ movl(tmp2, oldval);
686 __ decode_heap_oop(tmp2);
687 } else {
688 __ movptr(tmp2, oldval);
689 }
690
691 // Decode offending in-memory value.
692 // Test if-forwarded
693 __ testb(Address(tmp2, oopDesc::mark_offset_in_bytes()), markWord::marked_value);
694 __ jcc(Assembler::noParity, L_failure); // When odd number of bits, then not forwarded
695 __ jcc(Assembler::zero, L_failure); // When it is 00, then also not forwarded
757 // and promote the result. Note that we handle the flag from both the 1st and 2nd CAS.
758 // Otherwise, failure witness for CAE is in oldval on all paths, and we can return.
759
760 if (exchange) {
761 __ bind(L_failure);
762 __ bind(L_success);
763 } else {
764 assert(res != noreg, "need result register");
765
766 Label exit;
767 __ bind(L_failure);
768 __ xorptr(res, res);
769 __ jmpb(exit);
770
771 __ bind(L_success);
772 __ movptr(res, 1);
773 __ bind(exit);
774 }
775 }
776
777 #ifdef PRODUCT
778 #define BLOCK_COMMENT(str) /* nothing */
779 #else
780 #define BLOCK_COMMENT(str) __ block_comment(str)
781 #endif
782
783 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
784
785 #define TIMES_OOP (UseCompressedOops ? Address::times_4 : Address::times_8)
786
787 void ShenandoahBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
788 Register addr, Register count,
789 Register tmp) {
790 assert(ShenandoahCardBarrier, "Should have been checked by caller");
791
792 Label L_loop, L_done;
793 const Register end = count;
794 assert_different_registers(addr, end);
795
796 // Zero count? Nothing to do.
|
24 */
25
26 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
27 #include "gc/shenandoah/mode/shenandoahMode.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
30 #include "gc/shenandoah/shenandoahForwarding.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
33 #include "gc/shenandoah/shenandoahRuntime.hpp"
34 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
35 #include "interpreter/interpreter.hpp"
36 #include "runtime/javaThread.hpp"
37 #include "runtime/sharedRuntime.hpp"
38 #include "utilities/macros.hpp"
39 #ifdef COMPILER1
40 #include "c1/c1_LIRAssembler.hpp"
41 #include "c1/c1_MacroAssembler.hpp"
42 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
43 #endif
44 #ifdef COMPILER2
45 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
46 #endif
47
48 #define __ masm->
49
50 static void save_machine_state(MacroAssembler* masm, bool handle_gpr, bool handle_fp) {
51 if (handle_gpr) {
52 __ push_IU_state();
53 }
54
55 if (handle_fp) {
56 // Some paths can be reached from the c2i adapter with live fp arguments in registers.
57 assert(Argument::n_float_register_parameters_j == 8, "8 fp registers to save at java call");
58
59 const int xmm_size = wordSize * 2;
60 __ subptr(rsp, xmm_size * 8);
61 __ movdbl(Address(rsp, xmm_size * 0), xmm0);
62 __ movdbl(Address(rsp, xmm_size * 1), xmm1);
63 __ movdbl(Address(rsp, xmm_size * 2), xmm2);
64 __ movdbl(Address(rsp, xmm_size * 3), xmm3);
65 __ movdbl(Address(rsp, xmm_size * 4), xmm4);
66 __ movdbl(Address(rsp, xmm_size * 5), xmm5);
658 if (UseCompressedOops) {
659 __ lock();
660 __ cmpxchgl(newval, addr);
661 } else {
662 __ lock();
663 __ cmpxchgptr(newval, addr);
664 }
665 __ jcc(Assembler::equal, L_success);
666
667 // Step 2. CAS had failed. This may be a false negative.
668 //
669 // The trouble comes when we compare the to-space pointer with the from-space
670 // pointer to the same object. To resolve this, it will suffice to resolve
671 // the value from memory -- this will give both to-space pointers.
672 // If they mismatch, then it was a legitimate failure.
673 //
674 // Before reaching to resolve sequence, see if we can avoid the whole shebang
675 // with filters.
676
677 // Filter: when offending in-memory value is null, the failure is definitely legitimate
678 if (UseCompressedOops) {
679 __ testl(oldval, oldval);
680 } else {
681 __ testptr(oldval, oldval);
682 }
683 __ jcc(Assembler::zero, L_failure);
684
685 // Filter: when heap is stable, the failure is definitely legitimate
686 const Register thread = r15_thread;
687 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
688 __ testb(gc_state, ShenandoahHeap::HAS_FORWARDED);
689 __ jcc(Assembler::zero, L_failure);
690
691 if (UseCompressedOops) {
692 __ movl(tmp2, oldval);
693 __ decode_heap_oop(tmp2);
694 } else {
695 __ movptr(tmp2, oldval);
696 }
697
698 // Decode offending in-memory value.
699 // Test if-forwarded
700 __ testb(Address(tmp2, oopDesc::mark_offset_in_bytes()), markWord::marked_value);
701 __ jcc(Assembler::noParity, L_failure); // When odd number of bits, then not forwarded
702 __ jcc(Assembler::zero, L_failure); // When it is 00, then also not forwarded
764 // and promote the result. Note that we handle the flag from both the 1st and 2nd CAS.
765 // Otherwise, failure witness for CAE is in oldval on all paths, and we can return.
766
767 if (exchange) {
768 __ bind(L_failure);
769 __ bind(L_success);
770 } else {
771 assert(res != noreg, "need result register");
772
773 Label exit;
774 __ bind(L_failure);
775 __ xorptr(res, res);
776 __ jmpb(exit);
777
778 __ bind(L_success);
779 __ movptr(res, 1);
780 __ bind(exit);
781 }
782 }
783
784 #ifdef COMPILER2
785 void ShenandoahBarrierSetAssembler::load_ref_barrier_c2(const MachNode* node, MacroAssembler* masm, Register obj, Register addr, Register tmp1, Register tmp2, Register tmp3, bool narrow) {
786 if (!ShenandoahLoadRefBarrierStubC2::needs_barrier(node)) {
787 return;
788 }
789 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
790
791 ShenandoahLoadRefBarrierStubC2* const stub = ShenandoahLoadRefBarrierStubC2::create(node, obj, addr, tmp1, tmp2, tmp3, narrow);
792 stub->dont_preserve(obj);
793
794 // Test for null.
795 if (narrow) {
796 __ testl(obj, obj);
797 } else {
798 __ testptr(obj, obj);
799 }
800 __ jccb(Assembler::zero, *stub->continuation());
801
802 Address gc_state(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
803 int flags = ShenandoahHeap::HAS_FORWARDED;
804 bool is_strong = (node->barrier_data() & ShenandoahBarrierStrong) != 0;
805 if (!is_strong) {
806 flags |= ShenandoahHeap::WEAK_ROOTS;
807 }
808 __ testb(gc_state, flags);
809 __ jcc(Assembler::notZero, *stub->entry());
810 __ bind(*stub->continuation());
811 }
812
813 void ShenandoahBarrierSetAssembler::satb_barrier_c2(const MachNode* node, MacroAssembler* masm,
814 Register addr, Register preval, Register tmp) {
815 if (!ShenandoahSATBBarrierStubC2::needs_barrier(node)) {
816 return;
817 }
818 ShenandoahSATBBarrierStubC2* const stub = ShenandoahSATBBarrierStubC2::create(node, addr, preval, tmp);
819 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
820 Address gc_state(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
821 __ testb(gc_state, ShenandoahHeap::MARKING);
822 __ jcc(Assembler::notZero, *stub->entry());
823 __ bind(*stub->continuation());
824 }
825
826 void ShenandoahBarrierSetAssembler::card_barrier_c2(const MachNode* node, MacroAssembler* masm,
827 Register addr, Register addr_tmp, Register tmp) {
828 if (!ShenandoahCardBarrier ||
829 (node->barrier_data() & (ShenandoahBarrierCardMark | ShenandoahBarrierCardMarkNotNull)) == 0) {
830 return;
831 }
832 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
833 if (addr != noreg) {
834 __ mov(addr_tmp, addr);
835 }
836 __ shrptr(addr_tmp, CardTable::card_shift());
837
838 Address curr_ct_holder_addr(r15_thread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
839 __ movptr(tmp, curr_ct_holder_addr);
840 Address card_addr(tmp, addr_tmp, Address::times_1);
841
842 int dirty = CardTable::dirty_card_val();
843 if (UseCondCardMark) {
844 Label L_already_dirty;
845 __ cmpb(card_addr, dirty);
846 __ jccb(Assembler::equal, L_already_dirty);
847 __ movb(card_addr, dirty);
848 __ bind(L_already_dirty);
849 } else {
850 __ movb(card_addr, dirty);
851 }
852 }
853
854 void ShenandoahBarrierSetAssembler::cmpxchg_oop_c2(const MachNode* node, MacroAssembler* masm,
855 Register res, Address addr, Register oldval, Register newval, Register tmp1, Register tmp2,
856 bool exchange) {
857 assert(oldval == rax, "must be in rax for implicit use in cmpxchg");
858 assert_different_registers(oldval, tmp1, tmp2);
859 assert_different_registers(newval, tmp1, tmp2);
860
861 ShenandoahCASBarrierSlowStubC2* const slow_stub = ShenandoahCASBarrierSlowStubC2::create(node, addr, oldval, newval, res, tmp1, tmp2, exchange);
862 ShenandoahCASBarrierMidStubC2* const mid_stub = ShenandoahCASBarrierMidStubC2::create(node, slow_stub, oldval, res, tmp1, exchange);
863
864 Label L_success, L_failure;
865
866 // Remember oldval for retry logic below. It will be overwritten by the CAS.
867 if (ShenandoahCASBarrier) {
868 __ movptr(tmp2, oldval);
869 }
870
871 // Step 1. Fast-path.
872 //
873 // Try to CAS with given arguments. If successful, then we are done.
874 __ lock();
875 if (UseCompressedOops) {
876 __ cmpxchgl(newval, addr);
877 } else {
878 __ cmpxchgptr(newval, addr);
879 }
880
881 if (!ShenandoahCASBarrier) {
882 if (!exchange) {
883 assert(res != noreg, "need result register");
884 __ setcc(Assembler::equal, res);
885 }
886 return;
887 }
888
889 __ jcc(Assembler::notEqual, *mid_stub->entry());
890
891 // Slow-stub re-enters with condition flags according to CAS, we may need to
892 // set result accordingly.
893 __ bind(*slow_stub->continuation());
894
895 // Step 5. If we need a boolean result out of CAS, set the flag appropriately.
896 // and promote the result. Note that we handle the flag from both the 1st and 2nd CAS.
897 // Otherwise, failure witness for CAE is in oldval on all paths, and we can return.
898
899 if (!exchange) {
900 assert(res != noreg, "need result register");
901 __ setcc(Assembler::equal, res);
902 }
903
904 // Mid-stub re-enters with result set correctly.
905 __ bind(*mid_stub->continuation());
906 }
907
908 #undef __
909 #define __ masm.
910
911 void ShenandoahLoadRefBarrierStubC2::emit_code(MacroAssembler& masm) {
912 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
913 __ bind(*entry());
914
915 Register obj = _obj;
916 if (_narrow) {
917 __ movl(_tmp1, _obj);
918 __ decode_heap_oop(_tmp1);
919 obj = _tmp1;
920 }
921
922 // Weak/phantom loads always need to go to runtime.
923 if ((_node->barrier_data() & ShenandoahBarrierStrong) != 0) {
924 __ movptr(_tmp2, obj);
925 __ shrptr(_tmp2, ShenandoahHeapRegion::region_size_bytes_shift_jint());
926 __ movptr(_tmp3, (intptr_t) ShenandoahHeap::in_cset_fast_test_addr());
927 __ movbool(_tmp2, Address(_tmp2, _tmp3, Address::times_1));
928 __ testbool(_tmp2);
929 __ jcc(Assembler::zero, *continuation());
930 }
931
932 {
933 SaveLiveRegisters save_registers(&masm, this);
934 if (c_rarg0 != obj) {
935 if (c_rarg0 == _addr) {
936 __ movptr(_tmp2, _addr);
937 _addr = _tmp2;
938 }
939 __ movptr(c_rarg0, obj);
940 }
941 __ movptr(c_rarg1, _addr);
942
943 address entry;
944 if (_narrow) {
945 if ((_node->barrier_data() & ShenandoahBarrierStrong) != 0) {
946 entry = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow);
947 } else if ((_node->barrier_data() & ShenandoahBarrierWeak) != 0) {
948 entry = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow);
949 } else if ((_node->barrier_data() & ShenandoahBarrierPhantom) != 0) {
950 entry = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom_narrow);
951 }
952 } else {
953 if ((_node->barrier_data() & ShenandoahBarrierStrong) != 0) {
954 entry = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong);
955 } else if ((_node->barrier_data() & ShenandoahBarrierWeak) != 0) {
956 entry = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak);
957 } else if ((_node->barrier_data() & ShenandoahBarrierPhantom) != 0) {
958 entry = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom);
959 }
960 }
961 __ call(RuntimeAddress(entry), rax);
962 assert(!save_registers.contains(_obj), "must not save result register");
963 __ movptr(_obj, rax);
964 }
965 if (_narrow) {
966 __ encode_heap_oop(_obj);
967 }
968
969 __ jmp(*continuation());
970 }
971
972 void ShenandoahSATBBarrierStubC2::emit_code(MacroAssembler& masm) {
973 __ bind(*entry());
974 Address index(r15_thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
975 Address buffer(r15_thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
976
977 Label runtime;
978
979 // Do we need to load the previous value?
980 if (_addr != noreg) {
981 __ load_heap_oop(_preval, Address(_addr, 0), noreg, AS_RAW);
982 }
983 // Is the previous value null?
984 __ cmpptr(_preval, NULL_WORD);
985 __ jcc(Assembler::equal, *continuation());
986
987 // Can we store a value in the given thread's buffer?
988 // (The index field is typed as size_t.)
989 __ movptr(_tmp, index);
990 __ testptr(_tmp, _tmp);
991 __ jccb(Assembler::zero, runtime);
992 // The buffer is not full, store value into it.
993 __ subptr(_tmp, wordSize);
994 __ movptr(index, _tmp);
995 __ addptr(_tmp, buffer);
996 __ movptr(Address(_tmp, 0), _preval);
997
998 __ jmp(*continuation());
999
1000 __ bind(runtime);
1001 {
1002 SaveLiveRegisters save_registers(&masm, this);
1003 if (c_rarg0 != _preval) {
1004 __ mov(c_rarg0, _preval);
1005 }
1006 // rax is a caller-saved, non-argument-passing register, so it does not
1007 // interfere with c_rarg0 or c_rarg1. If it contained any live value before
1008 // entering this stub, it is saved at this point, and restored after the
1009 // call. If it did not contain any live value, it is free to be used. In
1010 // either case, it is safe to use it here as a call scratch register.
1011 __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre_c2)), rax);
1012 }
1013 __ jmp(*continuation());
1014 }
1015
1016 void ShenandoahCASBarrierMidStubC2::emit_code(MacroAssembler& masm) {
1017 __ bind(*entry());
1018
1019 if (!_cae) {
1020 // Set result to false, in case that we fail the following tests.
1021 // Failing those tests means legitimate failures.
1022 // Otherwise, result will be set correctly after returning from
1023 // the slow-path.
1024 __ movl(_result, 0); // Result = false.
1025 }
1026 // Check if CAS result is null. If it is, then we must have a legitimate failure.
1027 // This makes loading the fwdptr in the slow-path simpler.
1028 if (UseCompressedOops) {
1029 __ testl(_expected, _expected);
1030 } else {
1031 __ testptr(_expected, _expected);
1032 }
1033 __ jcc(Assembler::equal, *continuation());
1034
1035 // Check if GC is in progress, otherwise we must have a legitimate failure.
1036 Address gc_state(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
1037 __ testb(gc_state, ShenandoahHeap::HAS_FORWARDED);
1038 __ jcc(Assembler::notZero, *_slow_stub->entry());
1039 __ jmp(*continuation());
1040 }
1041
1042 void ShenandoahCASBarrierSlowStubC2::emit_code(MacroAssembler& masm) {
1043 __ bind(*entry());
1044
1045 assert(_expected == rax, "expected must be rax");
1046
1047 // Step 2. CAS has failed because the value held at addr does not
1048 // match expected. This may be a false negative because the value fetched
1049 // from addr (now held in result) may be a from-space pointer to the
1050 // original copy of same object referenced by to-space pointer expected.
1051 //
1052 // To resolve this, it suffices to find the forward pointer associated
1053 // with fetched value. If this matches expected, retry CAS with new
1054 // parameters. If this mismatches, then we have a legitimate
1055 // failure, and we're done.
1056
1057 // overwrite tmp1 with from-space pointer fetched from memory
1058 __ movptr(_tmp1, _expected);
1059
1060 if (UseCompressedOops) {
1061 __ decode_heap_oop_not_null(_tmp1);
1062 }
1063
1064 // Load/decode forwarding pointer.
1065 __ movq(_tmp1, Address(_tmp1, oopDesc::mark_offset_in_bytes()));
1066 // Negate the mark-word. This allows us to test lowest 2 bits easily while preserving the upper bits.
1067 __ negq(_tmp1);
1068 __ testq(_tmp1, markWord::lock_mask_in_place);
1069 // Not forwarded, must have a legit CAS failure.
1070 __ jcc(Assembler::notEqual, *continuation());
1071 // Set the lowest two bits. This is equivalent to clearing the two bits after
1072 // the subsequent inversion.
1073 __ orq(_tmp1, markWord::marked_value);
1074 // And invert back to get the forwardee.
1075 __ negq(_tmp1);
1076
1077 if (UseCompressedOops) {
1078 __ encode_heap_oop_not_null(_tmp1); // encode for comparison
1079 }
1080
1081 // Now we have the forwarded offender in tmp1.
1082 // We preserved the original expected value in tmp2 in the fast-path.
1083 // Compare and if they don't match, we have legitimate failure
1084 __ cmpptr(_tmp1, _tmp2);
1085 __ jcc(Assembler::notEqual, *continuation());
1086
1087 // Fall through to step 3.
1088
1089 // Step 3. We've confirmed that the value originally held in memory
1090 // (now held in result) pointed to from-space version of original
1091 // expected value. Try the CAS again with the from-space expected
1092 // value. If it now succeeds, we're good.
1093 //
1094 // Note: expected holds encoded from-space pointer that matches to-space
1095 // object residing at tmp1.
1096 __ lock();
1097 if (UseCompressedOops) {
1098 __ cmpxchgl(_new_val, _addr);
1099 } else {
1100 __ cmpxchgptr(_new_val, _addr);
1101 }
1102
1103 // If fetched value did not equal the new expected, this could
1104 // still be a false negative because some other (GC) thread may have
1105 // newly overwritten the memory value with its to-space equivalent.
1106 __ jcc(Assembler::equal, *continuation());
1107
1108 // Step 4. Try to CAS again, but with the original to-space expected.
1109 // This should be very rare.
1110 __ movptr(_expected, _tmp2);
1111 __ lock();
1112 if (UseCompressedOops) {
1113 __ cmpxchgl(_new_val, _addr);
1114 } else {
1115 __ cmpxchgptr(_new_val, _addr);
1116 }
1117 // At this point, there can no longer be false negatives.
1118 __ jmp(*continuation());
1119 }
1120
1121 #undef __
1122 #define __ masm->
1123 #endif
1124
1125 #ifdef PRODUCT
1126 #define BLOCK_COMMENT(str) /* nothing */
1127 #else
1128 #define BLOCK_COMMENT(str) __ block_comment(str)
1129 #endif
1130
1131 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
1132
1133 #define TIMES_OOP (UseCompressedOops ? Address::times_4 : Address::times_8)
1134
1135 void ShenandoahBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
1136 Register addr, Register count,
1137 Register tmp) {
1138 assert(ShenandoahCardBarrier, "Should have been checked by caller");
1139
1140 Label L_loop, L_done;
1141 const Register end = count;
1142 assert_different_registers(addr, end);
1143
1144 // Zero count? Nothing to do.
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