866 mtlr(R0);
867 BLOCK_COMMENT("} remove_activation");
868 }
869
870 // Lock object
871 //
872 // Registers alive
873 // monitor - Address of the BasicObjectLock to be used for locking,
874 // which must be initialized with the object to lock.
875 // object - Address of the object to be locked.
876 //
877 void InterpreterMacroAssembler::lock_object(Register monitor, Register object) {
878 if (UseHeavyMonitors) {
879 call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorenter),
880 monitor, /*check_for_exceptions=*/true);
881 } else {
882 // template code:
883 //
884 // markWord displaced_header = obj->mark().set_unlocked();
885 // monitor->lock()->set_displaced_header(displaced_header);
886 // if (Atomic::cmpxchg(/*ex=*/monitor, /*addr*/obj->mark_addr(), /*cmp*/displaced_header) == displaced_header) {
887 // // We stored the monitor address into the object's mark word.
888 // } else if (THREAD->is_lock_owned((address)displaced_header))
889 // // Simple recursive case.
890 // monitor->lock()->set_displaced_header(NULL);
891 // } else {
892 // // Slow path.
893 // InterpreterRuntime::monitorenter(THREAD, monitor);
894 // }
895
896 const Register displaced_header = R7_ARG5;
897 const Register object_mark_addr = R8_ARG6;
898 const Register current_header = R9_ARG7;
899 const Register tmp = R10_ARG8;
900
901 Label done;
902 Label cas_failed, slow_case;
903
904 assert_different_registers(displaced_header, object_mark_addr, current_header, tmp);
905
906 // markWord displaced_header = obj->mark().set_unlocked();
907
908 // Load markWord from object into displaced_header.
909 ld(displaced_header, oopDesc::mark_offset_in_bytes(), object);
910
911 if (UseBiasedLocking) {
912 biased_locking_enter(CCR0, object, displaced_header, tmp, current_header, done, &slow_case);
913 }
914
915 // Set displaced_header to be (markWord of object | UNLOCK_VALUE).
916 ori(displaced_header, displaced_header, markWord::unlocked_value);
917
918 // monitor->lock()->set_displaced_header(displaced_header);
919
920 // Initialize the box (Must happen before we update the object mark!).
921 std(displaced_header, BasicObjectLock::lock_offset_in_bytes() +
922 BasicLock::displaced_header_offset_in_bytes(), monitor);
923
924 // if (Atomic::cmpxchg(/*ex=*/monitor, /*addr*/obj->mark_addr(), /*cmp*/displaced_header) == displaced_header) {
925
926 // Store stack address of the BasicObjectLock (this is monitor) into object.
927 addi(object_mark_addr, object, oopDesc::mark_offset_in_bytes());
928
929 // Must fence, otherwise, preceding store(s) may float below cmpxchg.
930 // CmpxchgX sets CCR0 to cmpX(current, displaced).
931 cmpxchgd(/*flag=*/CCR0,
932 /*current_value=*/current_header,
933 /*compare_value=*/displaced_header, /*exchange_value=*/monitor,
934 /*where=*/object_mark_addr,
935 MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq,
936 MacroAssembler::cmpxchgx_hint_acquire_lock(),
937 noreg,
938 &cas_failed,
939 /*check without membar and ldarx first*/true);
940
941 // If the compare-and-exchange succeeded, then we found an unlocked
942 // object and we have now locked it.
943 b(done);
944 bind(cas_failed);
980 }
981
982 // Unlocks an object. Used in monitorexit bytecode and remove_activation.
983 //
984 // Registers alive
985 // monitor - Address of the BasicObjectLock to be used for locking,
986 // which must be initialized with the object to lock.
987 //
988 // Throw IllegalMonitorException if object is not locked by current thread.
989 void InterpreterMacroAssembler::unlock_object(Register monitor, bool check_for_exceptions) {
990 if (UseHeavyMonitors) {
991 call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorexit),
992 monitor, check_for_exceptions);
993 } else {
994
995 // template code:
996 //
997 // if ((displaced_header = monitor->displaced_header()) == NULL) {
998 // // Recursive unlock. Mark the monitor unlocked by setting the object field to NULL.
999 // monitor->set_obj(NULL);
1000 // } else if (Atomic::cmpxchg(displaced_header, obj->mark_addr(), monitor) == monitor) {
1001 // // We swapped the unlocked mark in displaced_header into the object's mark word.
1002 // monitor->set_obj(NULL);
1003 // } else {
1004 // // Slow path.
1005 // InterpreterRuntime::monitorexit(THREAD, monitor);
1006 // }
1007
1008 const Register object = R7_ARG5;
1009 const Register displaced_header = R8_ARG6;
1010 const Register object_mark_addr = R9_ARG7;
1011 const Register current_header = R10_ARG8;
1012
1013 Label free_slot;
1014 Label slow_case;
1015
1016 assert_different_registers(object, displaced_header, object_mark_addr, current_header);
1017
1018 if (UseBiasedLocking) {
1019 // The object address from the monitor is in object.
1020 ld(object, BasicObjectLock::obj_offset_in_bytes(), monitor);
1021 assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
1022 biased_locking_exit(CCR0, object, displaced_header, free_slot);
1023 }
1024
1025 // Test first if we are in the fast recursive case.
1026 ld(displaced_header, BasicObjectLock::lock_offset_in_bytes() +
1027 BasicLock::displaced_header_offset_in_bytes(), monitor);
1028
1029 // If the displaced header is zero, we have a recursive unlock.
1030 cmpdi(CCR0, displaced_header, 0);
1031 beq(CCR0, free_slot); // recursive unlock
1032
1033 // } else if (Atomic::cmpxchg(displaced_header, obj->mark_addr(), monitor) == monitor) {
1034 // // We swapped the unlocked mark in displaced_header into the object's mark word.
1035 // monitor->set_obj(NULL);
1036
1037 // If we still have a lightweight lock, unlock the object and be done.
1038
1039 // The object address from the monitor is in object.
1040 if (!UseBiasedLocking) { ld(object, BasicObjectLock::obj_offset_in_bytes(), monitor); }
1041 addi(object_mark_addr, object, oopDesc::mark_offset_in_bytes());
1042
1043 // We have the displaced header in displaced_header. If the lock is still
1044 // lightweight, it will contain the monitor address and we'll store the
1045 // displaced header back into the object's mark word.
1046 // CmpxchgX sets CCR0 to cmpX(current, monitor).
1047 cmpxchgd(/*flag=*/CCR0,
1048 /*current_value=*/current_header,
1049 /*compare_value=*/monitor, /*exchange_value=*/displaced_header,
1050 /*where=*/object_mark_addr,
1051 MacroAssembler::MemBarRel,
1052 MacroAssembler::cmpxchgx_hint_release_lock(),
1053 noreg,
|
866 mtlr(R0);
867 BLOCK_COMMENT("} remove_activation");
868 }
869
870 // Lock object
871 //
872 // Registers alive
873 // monitor - Address of the BasicObjectLock to be used for locking,
874 // which must be initialized with the object to lock.
875 // object - Address of the object to be locked.
876 //
877 void InterpreterMacroAssembler::lock_object(Register monitor, Register object) {
878 if (UseHeavyMonitors) {
879 call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorenter),
880 monitor, /*check_for_exceptions=*/true);
881 } else {
882 // template code:
883 //
884 // markWord displaced_header = obj->mark().set_unlocked();
885 // monitor->lock()->set_displaced_header(displaced_header);
886 // if (Atomic::cmpxchg(/*addr*/obj->mark_addr(), /*cmp*/displaced_header, /*ex=*/monitor) == displaced_header) {
887 // // We stored the monitor address into the object's mark word.
888 // } else if (THREAD->is_lock_owned((address)displaced_header))
889 // // Simple recursive case.
890 // monitor->lock()->set_displaced_header(NULL);
891 // } else {
892 // // Slow path.
893 // InterpreterRuntime::monitorenter(THREAD, monitor);
894 // }
895
896 const Register displaced_header = R7_ARG5;
897 const Register object_mark_addr = R8_ARG6;
898 const Register current_header = R9_ARG7;
899 const Register tmp = R10_ARG8;
900
901 Label done;
902 Label cas_failed, slow_case;
903
904 assert_different_registers(displaced_header, object_mark_addr, current_header, tmp);
905
906 // markWord displaced_header = obj->mark().set_unlocked();
907
908 // Load markWord from object into displaced_header.
909 ld(displaced_header, oopDesc::mark_offset_in_bytes(), object);
910
911 if (UseBiasedLocking) {
912 biased_locking_enter(CCR0, object, displaced_header, tmp, current_header, done, &slow_case);
913 }
914
915 // Set displaced_header to be (markWord of object | UNLOCK_VALUE).
916 ori(displaced_header, displaced_header, markWord::unlocked_value);
917
918 // monitor->lock()->set_displaced_header(displaced_header);
919
920 // Initialize the box (Must happen before we update the object mark!).
921 std(displaced_header, BasicObjectLock::lock_offset_in_bytes() +
922 BasicLock::displaced_header_offset_in_bytes(), monitor);
923
924 // if (Atomic::cmpxchg(/*addr*/obj->mark_addr(), /*cmp*/displaced_header, /*ex=*/monitor) == displaced_header) {
925
926 // Store stack address of the BasicObjectLock (this is monitor) into object.
927 addi(object_mark_addr, object, oopDesc::mark_offset_in_bytes());
928
929 // Must fence, otherwise, preceding store(s) may float below cmpxchg.
930 // CmpxchgX sets CCR0 to cmpX(current, displaced).
931 cmpxchgd(/*flag=*/CCR0,
932 /*current_value=*/current_header,
933 /*compare_value=*/displaced_header, /*exchange_value=*/monitor,
934 /*where=*/object_mark_addr,
935 MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq,
936 MacroAssembler::cmpxchgx_hint_acquire_lock(),
937 noreg,
938 &cas_failed,
939 /*check without membar and ldarx first*/true);
940
941 // If the compare-and-exchange succeeded, then we found an unlocked
942 // object and we have now locked it.
943 b(done);
944 bind(cas_failed);
980 }
981
982 // Unlocks an object. Used in monitorexit bytecode and remove_activation.
983 //
984 // Registers alive
985 // monitor - Address of the BasicObjectLock to be used for locking,
986 // which must be initialized with the object to lock.
987 //
988 // Throw IllegalMonitorException if object is not locked by current thread.
989 void InterpreterMacroAssembler::unlock_object(Register monitor, bool check_for_exceptions) {
990 if (UseHeavyMonitors) {
991 call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorexit),
992 monitor, check_for_exceptions);
993 } else {
994
995 // template code:
996 //
997 // if ((displaced_header = monitor->displaced_header()) == NULL) {
998 // // Recursive unlock. Mark the monitor unlocked by setting the object field to NULL.
999 // monitor->set_obj(NULL);
1000 // } else if (Atomic::cmpxchg(obj->mark_addr(), monitor, displaced_header) == monitor) {
1001 // // We swapped the unlocked mark in displaced_header into the object's mark word.
1002 // monitor->set_obj(NULL);
1003 // } else {
1004 // // Slow path.
1005 // InterpreterRuntime::monitorexit(THREAD, monitor);
1006 // }
1007
1008 const Register object = R7_ARG5;
1009 const Register displaced_header = R8_ARG6;
1010 const Register object_mark_addr = R9_ARG7;
1011 const Register current_header = R10_ARG8;
1012
1013 Label free_slot;
1014 Label slow_case;
1015
1016 assert_different_registers(object, displaced_header, object_mark_addr, current_header);
1017
1018 if (UseBiasedLocking) {
1019 // The object address from the monitor is in object.
1020 ld(object, BasicObjectLock::obj_offset_in_bytes(), monitor);
1021 assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
1022 biased_locking_exit(CCR0, object, displaced_header, free_slot);
1023 }
1024
1025 // Test first if we are in the fast recursive case.
1026 ld(displaced_header, BasicObjectLock::lock_offset_in_bytes() +
1027 BasicLock::displaced_header_offset_in_bytes(), monitor);
1028
1029 // If the displaced header is zero, we have a recursive unlock.
1030 cmpdi(CCR0, displaced_header, 0);
1031 beq(CCR0, free_slot); // recursive unlock
1032
1033 // } else if (Atomic::cmpxchg(obj->mark_addr(), monitor, displaced_header) == monitor) {
1034 // // We swapped the unlocked mark in displaced_header into the object's mark word.
1035 // monitor->set_obj(NULL);
1036
1037 // If we still have a lightweight lock, unlock the object and be done.
1038
1039 // The object address from the monitor is in object.
1040 if (!UseBiasedLocking) { ld(object, BasicObjectLock::obj_offset_in_bytes(), monitor); }
1041 addi(object_mark_addr, object, oopDesc::mark_offset_in_bytes());
1042
1043 // We have the displaced header in displaced_header. If the lock is still
1044 // lightweight, it will contain the monitor address and we'll store the
1045 // displaced header back into the object's mark word.
1046 // CmpxchgX sets CCR0 to cmpX(current, monitor).
1047 cmpxchgd(/*flag=*/CCR0,
1048 /*current_value=*/current_header,
1049 /*compare_value=*/monitor, /*exchange_value=*/displaced_header,
1050 /*where=*/object_mark_addr,
1051 MacroAssembler::MemBarRel,
1052 MacroAssembler::cmpxchgx_hint_release_lock(),
1053 noreg,
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