1 /*
2 * Copyright (c) 2024, 2026, 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 */
23
24 import jdk.incubator.code.*;
25 import jdk.incubator.code.Reflect;
26 import jdk.incubator.code.dialect.core.SSA;
27 import org.junit.jupiter.api.Assertions;
28 import org.junit.jupiter.api.Test;
29
30 import java.lang.invoke.MethodHandles;
31 import java.lang.reflect.Method;
32 import java.util.Optional;
33 import java.util.function.Predicate;
34 import java.util.stream.Stream;
35
36 import static jdk.incubator.code.dialect.core.CoreOp.FuncOp;
37 import static jdk.incubator.code.dialect.core.CoreOp.VarAccessOp.VarLoadOp;
38 import static jdk.incubator.code.dialect.core.CoreOp.VarAccessOp.VarStoreOp;
39 import static jdk.incubator.code.dialect.core.CoreOp.VarOp;
40
41 /*
42 * @test
43 * @modules jdk.incubator.code
44 * @library lib
45 * @run junit TestRemoveFinalVars
46 */
47
48 public class TestRemoveFinalVars {
49
50 @Reflect
51 static boolean f() {
52 final int x = 8; // final var
53 int y = x + 2; // final var
54 int z = y + 3; // non final var
55 z++;
56 return x == 8 && y == 10 && z == 14;
57 }
58
59 @Test
60 void test() {
61 FuncOp f = getFuncOp(this.getClass(),"f");
62 System.out.println(f.toText());
63 FuncOp lf = lower(f);
64 System.out.println(lf.toText());
65
66 FuncOp f2 = f.transform(TestRemoveFinalVars::rmFinalVars);
67 System.out.println(f2.toText());
68 FuncOp lf2 = lower(f2);
69 System.out.println(lf2.toText());
70
71 Assertions.assertEquals(Interpreter.invoke(MethodHandles.lookup(), lf2), Interpreter.invoke(MethodHandles.lookup(), lf));
72
73 Op op = SSA.transform(lower(f));
74 System.out.println(op.toText());
75 }
76
77 static FuncOp lower(FuncOp funcOp) {
78 return funcOp.transform(CodeTransformer.LOWERING_TRANSFORMER);
79 }
80
81 static Block.Builder rmFinalVars(Block.Builder block, Op op) {
82 if (op instanceof VarOp varOp) {
83 // Is the variable stored to? If not we can remove it
84 // otherwise, it's not considered final and we copy it
85 if (isValueUsedWithOp(varOp.result(), o -> o instanceof VarStoreOp)) {
86 block.add(varOp);
87 }
88 } else if (op instanceof VarLoadOp varLoadOp) {
89 // If the variable is not stored to
90 if (!isValueUsedWithOp(varLoadOp.varOp().result(), o -> o instanceof VarStoreOp)) {
91 // Map result of load from variable to the value that initialized the variable
92 // Subsequently encountered input operations using the result will be copied
93 // to output operations using the mapped value
94 CodeContext cc = block.context();
95 cc.mapValue(varLoadOp.result(), cc.getValue(varLoadOp.varOp().operands().get(0)));
96 } else {
97 block.add(varLoadOp);
98 }
99 } else {
100 block.add(op);
101 }
102 return block;
103 }
104
105 private static boolean isValueUsedWithOp(Value value, Predicate<Op> opPredicate) {
106 for (Op.Result user : value.uses()) {
107 if (opPredicate.test(user.op())) {
108 return true;
109 }
110 }
111 return false;
112 }
113
114 static FuncOp getFuncOp(Class<?> c, String name) {
115 Optional<Method> om = Stream.of(c.getDeclaredMethods())
116 .filter(m -> m.getName().equals(name))
117 .findFirst();
118
119 Method m = om.get();
120 return Op.ofMethod(m).get();
121 }
122 }