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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.lang.invoke;
  27 
  28 import java.util.Map;
  29 import jdk.internal.org.objectweb.asm.ClassWriter;
  30 import jdk.internal.org.objectweb.asm.Opcodes;
  31 
  32 /**
  33  * Helper class to assist the GenerateJLIClassesPlugin to get access to
  34  * generate classes ahead of time.
  35  */
  36 class GenerateJLIClassesHelper {
  37 
  38     static byte[] generateDMHClassBytes(String className,
  39             MethodType[] methodTypes, int[] types) {
  40         LambdaForm[] forms = new LambdaForm[methodTypes.length];
  41         for (int i = 0; i < forms.length; i++) {
  42             forms[i] = DirectMethodHandle.makePreparedLambdaForm(methodTypes[i],
  43                                                                  types[i]);
  44             methodTypes[i] = forms[i].methodType();
  45         }
  46         return generateCodeBytesForLFs(className, forms, methodTypes);
  47     }
  48 
  49     /*
  50      * Generate customized code for a set of LambdaForms of specified types into
  51      * a class with a specified name.
  52      */
  53     private static byte[] generateCodeBytesForLFs(String className,
  54             LambdaForm[] forms, MethodType[] types) {
  55         assert(forms.length == types.length);
  56 
  57         ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
  58         cw.visit(Opcodes.V1_8, Opcodes.ACC_PRIVATE + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
  59                 className, null, InvokerBytecodeGenerator.INVOKER_SUPER_NAME, null);
  60         cw.visitSource(className.substring(className.lastIndexOf('/') + 1), null);
  61         for (int i = 0; i < forms.length; i++) {
  62             InvokerBytecodeGenerator g
  63                     = new InvokerBytecodeGenerator(className, forms[i], types[i]);
  64             g.setClassWriter(cw);
  65             g.addMethod();
  66         }
  67         return cw.toByteArray();
  68     }
  69 
  70     static Map.Entry<String, byte[]> generateConcreteBMHClassBytes(
  71             final String types) {
  72         for (char c : types.toCharArray()) {
  73             if ("LIJFD".indexOf(c) < 0) {
  74                 throw new IllegalArgumentException("All characters must "
  75                         + "correspond to a basic field type: LIJFD");
  76             }
  77         }
  78         String shortTypes = LambdaForm.shortenSignature(types);
  79         final String className =
  80                 BoundMethodHandle.Factory.speciesInternalClassName(shortTypes);
  81         return Map.entry(className,
  82                          BoundMethodHandle.Factory.generateConcreteBMHClassBytes(
  83                                  shortTypes, types, className));
  84     }
  85 }