dev/core/test/com/google/gwt/dev/jjs/impl/DevirtualizerTest.java

/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.gwt.dev.jjs.impl;

import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.dev.jjs.ast.JMethod;
import com.google.gwt.dev.jjs.ast.JProgram;
import com.google.gwt.thirdparty.guava.common.collect.Lists;

/**
 * Tests for the {@link Devirtualizer} visitor.
 */
public class DevirtualizerTest extends OptimizerTestBase {

  /**
   * Devirtualizer should allow dual Java/JSO implementations of the same
   * interface, so long as there is only one of each. If there are multiple
   * methods with the same method name, it should distinguish between them.
   */
  public void testDualJsoImpl() throws UnableToCompleteException {

    addSnippetImport("com.google.gwt.lang.Cast");
    addSnippetImport("com.google.gwt.core.client.JavaScriptObject");

    // Defines a bunch of JSO interfaces and classes with functions a() and b().
    addSnippetClassDecl(
        "interface Iface1 { int a(); int b(); }",
        "static class J1 implements Iface1 {",
        "  public int a() { return 1; }",
        "  public int b() { return 1; }",
        "}",
        "static class Jso1 extends JavaScriptObject implements Iface1 {",
        "  protected Jso1() { }",
        "  public final int a() { return 2; }",
        "  public final int b() { return 2; }",
        "  public static native Jso1 create() /*-{ return {} }-*/;",
        "}",
        "static interface Iface2 { int a(); int b(); }",
        "static class J2 implements Iface2 {",
        "  public int a() { return 3; }",
        "  public int b() { return 3; }",
        "}",
        "static class Jso2 extends JavaScriptObject implements Iface2 {",
        "  protected Jso2() { }",
        "  public final int a() { return 4; }",
        "  public final int b() { return 4; }",
        "  public static native Jso2 create() /*-{ return {} }-*/;",
        "}",
        "static Iface1 val1 = new J1();",
        "static Iface1 val2 = Jso1.create();",
        "static Iface2 val3 = new J2();",
        "static Iface2 val4 = Jso2.create();");

    // Constructs a code snippet that calls a() but NOT b().
    StringBuilder code = new StringBuilder();
    code.append("int result = val1.a() + val2.a() + val3.a() + val4.a();");

    // Constructs an expectation about the resulting devirtualized method calls of a(). The salient
    // point in the results below is that the JSO method used for val1 and val1 has a different name
    // the method used for val2 and val3.
    StringBuilder expected = new StringBuilder();
    expected.append("int result = ");
    expected.append("EntryPoint$Jso1.a__I__devirtual$(EntryPoint.val1) + ");
    expected.append("EntryPoint$Jso1.a__I__devirtual$(EntryPoint.val2) + ");
    expected.append("EntryPoint$Jso2.a__I__devirtual$(EntryPoint.val3) + ");
    expected.append("EntryPoint$Jso2.a__I__devirtual$(EntryPoint.val4);");

    Result result = optimize("void", code.toString());
    // Asserts that a() method calls were redirected to the devirtualized version.
    result.intoString(expected.toString());
    // Asserts that a() AND b() method definitions were both duplicated as devirtualized versions
    // even though b() was never called.
    result.classHasMethodSnippets("EntryPoint$Jso1", Lists.newArrayList("public final int a();",
        "public final int b();", "public static final int $a(EntryPoint$Jso1 this$static);",
        "public static final int $b(EntryPoint$Jso1 this$static);"));
  }

  public void testDevirtualizeString() throws UnableToCompleteException {

    addSnippetImport("com.google.gwt.lang.Cast");
    addSnippetImport("com.google.gwt.core.client.JavaScriptObject");

    // Defines a JSO and a Java object that implements Comparable.
    addSnippetClassDecl(
        "static class J1 implements Comparable<J1> {",
        "  public int compareTo(J1 other) { return 1; }",
        "}",
        "static class Jso1 extends JavaScriptObject implements Comparable<Jso1> {",
        "  protected Jso1() { }",
        "  final public int compareTo(Jso1 other) { return 2; }",
        "  public static native Jso1 create() /*-{ return {} }-*/;",
        "}",
        "static Comparable javaVal = new J1();",
        "static Comparable jsoVal = Jso1.create();",
        "static Comparable stringVal = \"string\";",
        "static String aString = \"string\";",
        "static CharSequence stringCharSeq = \"string\";");

    // Constructs a code snippet that calls a() but NOT b().
    StringBuilder code = new StringBuilder();
    code.append("int result = javaVal.compareTo(javaVal) + jsoVal.compareTo(jsoVal) +"
        + " stringVal.compareTo(stringVal) + stringCharSeq.length() + aString.length();");

    // Constructs an expectation about the resulting devirtualized method calls for
    // Comparable.compareTo() and CharSequence.length(). Note that calls to CharSequence.length and
    // String.length are devirtualized separately.
    StringBuilder expected = new StringBuilder();
    expected.append("int result = ");
    expected.append(String.format(
        // Methods in Comparable and CharSequence end up in String even if used by a JSO.
        "String.compareTo_%s__I__devirtual$(EntryPoint.javaVal, EntryPoint.javaVal) + " +
        "String.compareTo_%s__I__devirtual$(EntryPoint.jsoVal, EntryPoint.jsoVal) + " +
        "String.compareTo_%s__I__devirtual$(EntryPoint.stringVal, EntryPoint.stringVal) + " +
        "String.length__I__devirtual$(EntryPoint.stringCharSeq) + " +
        "String.length__I__devirtual$(EntryPoint.aString);", "Ljava_lang_Object",
        "Ljava_lang_Object", "Ljava_lang_Object"));

    Result result = optimize("void", code.toString());
    result.intoString(expected.toString());
  }

  @Override
  protected boolean optimizeMethod(JProgram program, JMethod method) {
    Devirtualizer.exec(program);
    return true;
  }
}