1 /*
   2  * Copyright (c) 2015, 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 package jdk.tools.jlink.internal.plugins.optim;
  26 
  27 import java.util.Iterator;
  28 import java.util.Set;
  29 import jdk.internal.org.objectweb.asm.ClassReader;
  30 import jdk.internal.org.objectweb.asm.tree.AbstractInsnNode;
  31 import jdk.internal.org.objectweb.asm.tree.ClassNode;
  32 import jdk.internal.org.objectweb.asm.tree.MethodInsnNode;
  33 import jdk.internal.org.objectweb.asm.tree.MethodNode;
  34 import jdk.internal.org.objectweb.asm.tree.TryCatchBlockNode;
  35 
  36 /**
  37  * Optimization utility methods
  38  */
  39 public class Utils {
  40 
  41     public static boolean canThrowCheckedException(ReflectionOptimizer.TypeResolver cch,
  42             ClassNode classNode, MethodNode m, TryCatchBlockNode bn) throws Exception {
  43         int istart = m.instructions.indexOf(bn.start);
  44         int iend = m.instructions.indexOf(bn.end);
  45         for (int i = istart; i < iend - 1; i++) {
  46             AbstractInsnNode instr = m.instructions.get(i);
  47             if (instr instanceof MethodInsnNode) {
  48                 MethodInsnNode meth = (MethodInsnNode) instr;
  49                 ClassReader reader = cch.resolve(classNode, m, meth.owner);
  50                 if (reader != null) {
  51                     ClassNode cn = new ClassNode();
  52                     reader.accept(cn, ClassReader.EXPAND_FRAMES);
  53                     for (MethodNode method : cn.methods) {
  54                         if (method.name.equals(meth.name)) {
  55                             for (String e : method.exceptions) {
  56                                 if (e.equals(bn.type)) {
  57                                     return true;
  58                                 }
  59                             }
  60                         }
  61                     }
  62                 } else {
  63                     return true;
  64                 }
  65             }
  66         }
  67         return false;
  68     }
  69 
  70     public static void suppressBlocks(MethodNode m, Set<ControlFlow.Block> toRemove) throws Exception {
  71         m.instructions.resetLabels();
  72         Iterator<AbstractInsnNode> it = m.instructions.iterator();
  73         while (it.hasNext()) {
  74             AbstractInsnNode n = it.next();
  75             Iterator<TryCatchBlockNode> handlers = m.tryCatchBlocks.iterator();
  76             boolean cont = false;
  77             // Do not delete instructions that are end of other try block.
  78             while (handlers.hasNext()) {
  79                 TryCatchBlockNode handler = handlers.next();
  80                 if (handler.end == n) {
  81                     cont = true;
  82                 }
  83             }
  84             if (cont) {
  85                 continue;
  86             }
  87 
  88             for (ControlFlow.Block b : toRemove) {
  89                 for (ControlFlow.InstructionNode ins : b.getInstructions()) {
  90                     if (ins.getInstr() == n) {
  91                         it.remove();
  92                     }
  93                 }
  94             }
  95         }
  96     }
  97 }