1 /*
2 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. 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 *
851 }
852 }
853 }
854
855
856 void NullCheckEliminator::iterate(BlockBegin* block) {
857 work_list()->push(block);
858 iterate_all();
859 }
860
861 void NullCheckEliminator::handle_AccessField(AccessField* x) {
862 if (x->is_static()) {
863 if (x->as_LoadField() != NULL) {
864 // If the field is a non-null static final object field (as is
865 // often the case for sun.misc.Unsafe), put this LoadField into
866 // the non-null map
867 ciField* field = x->field();
868 if (field->is_constant()) {
869 ciConstant field_val = field->constant_value();
870 BasicType field_type = field_val.basic_type();
871 if (field_type == T_OBJECT || field_type == T_ARRAY) {
872 ciObject* obj_val = field_val.as_object();
873 if (!obj_val->is_null_object()) {
874 if (PrintNullCheckElimination) {
875 tty->print_cr("AccessField %d proven non-null by static final non-null oop check",
876 x->id());
877 }
878 set_put(x);
879 }
880 }
881 }
882 }
883 // Be conservative
884 clear_last_explicit_null_check();
885 return;
886 }
887
888 Value obj = x->obj();
889 if (set_contains(obj)) {
890 // Value is non-null => update AccessField
891 if (last_explicit_null_check_obj() == obj && !x->needs_patching()) {
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1 /*
2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. 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 *
851 }
852 }
853 }
854
855
856 void NullCheckEliminator::iterate(BlockBegin* block) {
857 work_list()->push(block);
858 iterate_all();
859 }
860
861 void NullCheckEliminator::handle_AccessField(AccessField* x) {
862 if (x->is_static()) {
863 if (x->as_LoadField() != NULL) {
864 // If the field is a non-null static final object field (as is
865 // often the case for sun.misc.Unsafe), put this LoadField into
866 // the non-null map
867 ciField* field = x->field();
868 if (field->is_constant()) {
869 ciConstant field_val = field->constant_value();
870 BasicType field_type = field_val.basic_type();
871 if (is_reference_type(field_type)) {
872 ciObject* obj_val = field_val.as_object();
873 if (!obj_val->is_null_object()) {
874 if (PrintNullCheckElimination) {
875 tty->print_cr("AccessField %d proven non-null by static final non-null oop check",
876 x->id());
877 }
878 set_put(x);
879 }
880 }
881 }
882 }
883 // Be conservative
884 clear_last_explicit_null_check();
885 return;
886 }
887
888 Value obj = x->obj();
889 if (set_contains(obj)) {
890 // Value is non-null => update AccessField
891 if (last_explicit_null_check_obj() == obj && !x->needs_patching()) {
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