1 /*
   2  * Copyright (c) 2010, 2013, 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 jdk.nashorn.internal.codegen;
  27 
  28 import java.io.Serializable;
  29 import java.util.Set;
  30 import java.util.TreeSet;
  31 import jdk.nashorn.internal.ir.CompileUnitHolder;
  32 
  33 /**
  34   * Used to track split class compilation. Note that instances of the class are serializable, but all fields are
  35   * transient, making the serialized version of the class only useful for tracking the referential topology of other
  36   * AST nodes referencing the same or different compile units. We do want to preserve this topology though as
  37   * {@link CompileUnitHolder}s in a deserialized AST will undergo reinitialization.
  38   */
  39 public final class CompileUnit implements Comparable<CompileUnit>, Serializable {
  40     private static final long serialVersionUID = 1L;
  41 
  42     /** Current class name */
  43     private transient final String className;
  44 
  45     /** Current class generator */
  46     private transient ClassEmitter classEmitter;
  47 
  48     private transient long weight;
  49 
  50     private transient Class<?> clazz;
  51 
  52     private transient boolean isUsed;
  53 
  54     private static int emittedUnitCount;
  55 
  56     CompileUnit(final String className, final ClassEmitter classEmitter, final long initialWeight) {
  57         this.className    = className;
  58         this.weight       = initialWeight;
  59         this.classEmitter = classEmitter;
  60     }
  61 
  62     static Set<CompileUnit> createCompileUnitSet() {
  63         return new TreeSet<>();
  64     }
  65 
  66     static void increaseEmitCount() {
  67         emittedUnitCount++;
  68     }
  69 
  70     /**
  71      * Get the amount of emitted compile units so far in the system
  72      * @return emitted compile unit count
  73      */
  74     public static int getEmittedUnitCount() {
  75         return emittedUnitCount;
  76     }
  77 
  78     /**
  79      * Check if this compile unit is used
  80      * @return true if tagged as in use - i.e active code that needs to be generated
  81      */
  82     public boolean isUsed() {
  83         return isUsed;
  84     }
  85 
  86     /**
  87      * Check if a compile unit has code, not counting inits and clinits
  88      * @return true of if there is "real code" in the compile unit
  89      */
  90     public boolean hasCode() {
  91         return (classEmitter.getMethodCount() - classEmitter.getInitCount() - classEmitter.getClinitCount()) > 0;
  92     }
  93 
  94     /**
  95      * Tag this compile unit as used
  96      */
  97     public void setUsed() {
  98         this.isUsed = true;
  99     }
 100 
 101     /**
 102      * Return the class that contains the code for this unit, null if not
 103      * generated yet
 104      *
 105      * @return class with compile unit code
 106      */
 107     public Class<?> getCode() {
 108         return clazz;
 109     }
 110 
 111     /**
 112      * Set class when it exists. Only accessible from compiler
 113      * @param clazz class with code for this compile unit
 114      */
 115     void setCode(final Class<?> clazz) {
 116         clazz.getClass(); // null check
 117         this.clazz = clazz;
 118         // Revisit this - refactor to avoid null-ed out non-final fields
 119         // null out emitter
 120         this.classEmitter = null;
 121     }
 122 
 123     /**
 124      * Add weight to this compile unit
 125      * @param w weight to add
 126      */
 127     void addWeight(final long w) {
 128         this.weight += w;
 129     }
 130 
 131     /**
 132      * Check if this compile unit can hold {@code weight} more units of weight
 133      * @param w weight to check if can be added
 134      * @return true if weight fits in this compile unit
 135      */
 136     public boolean canHold(final long w) {
 137         return (this.weight + w) < Splitter.SPLIT_THRESHOLD;
 138     }
 139 
 140     /**
 141      * Get the class emitter for this compile unit
 142      * @return class emitter
 143      */
 144     public ClassEmitter getClassEmitter() {
 145         return classEmitter;
 146     }
 147 
 148     /**
 149      * Get the class name for this compile unit
 150      * @return the class name
 151      */
 152     public String getUnitClassName() {
 153         return className;
 154     }
 155 
 156     private static String shortName(final String name) {
 157         return name == null ? null : name.lastIndexOf('/') == -1 ? name : name.substring(name.lastIndexOf('/') + 1);
 158     }
 159 
 160     @Override
 161     public String toString() {
 162         final String methods = classEmitter != null ? classEmitter.getMethodNames().toString() : "<anon>";
 163         return "[CompileUnit className=" + shortName(className) + " weight=" + weight + '/' + Splitter.SPLIT_THRESHOLD + " hasCode=" + methods + ']';
 164     }
 165 
 166     @Override
 167     public int compareTo(final CompileUnit o) {
 168         return className.compareTo(o.className);
 169     }
 170 }