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 

    24 /*

    25  * @test

    26  * @bug 7020499

    27  * @summary Verify that try-with-resources desugaring is not generating unnecessary null checks

    28  * @library /tools/lib

    29  * @modules jdk.compiler/com.sun.tools.javac.api

    30  *          jdk.compiler/com.sun.tools.javac.code

    31  *          jdk.compiler/com.sun.tools.javac.comp

    32  *          jdk.compiler/com.sun.tools.javac.main

    33  *          jdk.compiler/com.sun.tools.javac.tree

    34  *          jdk.compiler/com.sun.tools.javac.util

    35  * @build toolbox.ToolBox toolbox.JavacTask TwrAvoidNullCheck

    36  * @run main TwrAvoidNullCheck

    37  */

    38 

    39 import java.io.IOException;

    40 import java.util.Arrays;

    41 

    42 import com.sun.source.util.JavacTask;

    43 import com.sun.tools.javac.api.JavacTool;

    44 import com.sun.tools.javac.comp.AttrContext;

    45 import com.sun.tools.javac.comp.Env;

    46 import com.sun.tools.javac.comp.Lower;

    47 import com.sun.tools.javac.tree.JCTree;

    48 import com.sun.tools.javac.tree.JCTree.JCBinary;

    49 import com.sun.tools.javac.tree.TreeInfo;

    50 import com.sun.tools.javac.tree.TreeMaker;

    51 import com.sun.tools.javac.tree.TreeScanner;

    52 import com.sun.tools.javac.util.Context;

    53 import com.sun.tools.javac.util.Context.Factory;

    54 import com.sun.tools.javac.util.List;

    55 

    56 import toolbox.ToolBox;

    57 

    58 public class TwrAvoidNullCheck {

    59     public static void main(String... args) throws IOException {

    60         new TwrAvoidNullCheck().run();

    61     }

    62     void run() throws IOException {

    63         run("new Test()", false);

    64         run("null", true);

    65         run("System.getProperty(\"test\") != null ? new Test() : null", true);

    66     }

    67     void run(String resourceSpecification, boolean expected) throws IOException {

    68         String template = "public class Test implements AutoCloseable {\n" +

    69                           "    void t() {\n" +

    70                           "        try (Test resource = RESOURCE) { }\n" +

    71                           "    }\n" +

    72                           "    public void close() { }\n" +

    73                           "}\n";

    74         String code = template.replace("RESOURCE", resourceSpecification);

    75         Context ctx = new Context();

    76         DumpLower.preRegister(ctx);

    77         Iterable<ToolBox.JavaSource> files = Arrays.asList(new ToolBox.JavaSource(code));

    78         JavacTask task = JavacTool.create().getTask(null, null, null, null, null, files, ctx);

    79         task.call();

    80 

    81         boolean hasNullCheck = ((DumpLower) DumpLower.instance(ctx)).hasNullCheck;

    82 

    83         if (hasNullCheck != expected) {

    84             throw new IllegalStateException("expected: " + expected +

    85                                             "; actual: " + hasNullCheck +

    86                                             "; code: " + code);

    87         }

    88     }

    89 

    90     static class DumpLower extends Lower {

    91 

    92         public static void preRegister(Context ctx) {

    93             ctx.put(lowerKey, new Factory<Lower>() {

    94                 @Override

    95                 public Lower make(Context c) {

    96                     return new DumpLower(c);

    97                 }

    98             });

    99         }

   100 

   101         public DumpLower(Context context) {

   102             super(context);

   103         }

   104 

   105         boolean hasNullCheck;

   106 

   107         @Override

   108         public List<JCTree> translateTopLevelClass(Env<AttrContext> env, JCTree cdef, TreeMaker make) {

   109             List<JCTree> result = super.translateTopLevelClass(env, cdef, make);

   110 

   111             new TreeScanner() {

   112                 @Override

   113                 public void visitBinary(JCBinary tree) {

   114                     hasNullCheck |= tree.operator.getSimpleName().contentEquals("!=") &&

   115                                     "resource".equals(String.valueOf(TreeInfo.name(tree.lhs))) &&

   116                                     TreeInfo.isNull(tree.rhs);

   117                     super.visitBinary(tree);

   118                 }

   119             }.scan(result);

   120 

   121             return result;

   122         }

   123 

   124     }

   125 }