1 /*
   2  * Copyright (c) 2016, 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 package org.graalvm.compiler.replacements.test;
  24 
  25 import org.graalvm.compiler.core.test.GraalCompilerTest;
  26 import org.graalvm.compiler.nodes.ConstantNode;
  27 import org.graalvm.compiler.nodes.FixedNode;
  28 import org.graalvm.compiler.nodes.ReturnNode;
  29 import org.graalvm.compiler.nodes.StructuredGraph;
  30 import org.graalvm.compiler.nodes.ValueNode;
  31 import jdk.vm.ci.meta.JavaConstant;
  32 import org.junit.Test;
  33 
  34 import jdk.vm.ci.meta.ResolvedJavaMethod;
  35 import static org.hamcrest.CoreMatchers.instanceOf;
  36 import org.junit.Assert;
  37 
  38 /**
  39  * Tests constant folding of string equality.
  40  */
  41 public class StringEqualsConstantTest extends GraalCompilerTest {
  42 
  43     private ValueNode asConstant(StructuredGraph graph, String str) {
  44         return ConstantNode.forConstant(getSnippetReflection().forObject(str), getMetaAccess(), graph);
  45     }
  46 
  47     private void testStringEquals(String s0, String s1) {
  48         ResolvedJavaMethod method = getResolvedJavaMethod("stringEquals");
  49         StructuredGraph graph = parseForCompile(method);
  50 
  51         graph.getParameter(0).replaceAndDelete(asConstant(graph, s0));
  52         graph.getParameter(1).replaceAndDelete(asConstant(graph, s1));
  53 
  54         compile(method, graph);
  55 
  56         FixedNode firstFixed = graph.start().next();
  57         Assert.assertThat(firstFixed, instanceOf(ReturnNode.class));
  58 
  59         ReturnNode ret = (ReturnNode) firstFixed;
  60         JavaConstant result = ret.result().asJavaConstant();
  61         if (result == null) {
  62             Assert.fail("result not constant: " + ret.result());
  63         } else {
  64             int expected = s0.equals(s1) ? 1 : 0;
  65             Assert.assertEquals("result", expected, result.asInt());
  66         }
  67     }
  68 
  69     @Test
  70     public void testSameString() {
  71         String s = "equal-string";
  72         testStringEquals(s, s);
  73     }
  74 
  75     @Test
  76     public void testEqualString() {
  77         String s = "equal-string";
  78         testStringEquals(s, new String(s.toCharArray()));
  79     }
  80 
  81     @Test
  82     public void testDifferentString() {
  83         testStringEquals("some-string", "different-string");
  84     }
  85 
  86     @Test
  87     public void testSameLengthString() {
  88         testStringEquals("string-1", "string-2");
  89     }
  90 
  91     public static boolean stringEquals(String a, String b) {
  92         return a.equals(b);
  93     }
  94 }