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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   *
17   */
18  package org.apache.bcel.generic;
19  
20  import org.apache.bcel.Const;
21  
22  /**
23   * This interface contains shareable instruction objects.
24   *
25   * In order to save memory you can use some instructions multiply,
26   * since they have an immutable state and are directly derived from
27   * Instruction.  I.e. they have no instance fields that could be
28   * changed. Since some of these instructions like ICONST_0 occur
29   * very frequently this can save a lot of time and space. This
30   * feature is an adaptation of the FlyWeight design pattern, we
31   * just use an array instead of a factory.
32   *
33   * The Instructions can also accessed directly under their names, so
34   * it's possible to write il.append(Instruction.ICONST_0);
35   *
36   */
37  public final class InstructionConst {
38  
39      /**
40       * Predefined instruction objects
41       */
42      /*
43       * NOTE these are not currently immutable, because Instruction
44       * has mutable protected fields opcode and length.
45       */
46      public static final Instruction NOPneric/NOP.html#NOP">NOP = new NOP();
47      public static final Instruction ACONST_NULLONST_NULL.html#ACONST_NULL">ACONST_NULL = new ACONST_NULL();
48      public static final Instruction ICONST_M1 = new ICONST(-1);
49      public static final Instruction ICONST_0 = new ICONST(0);
50      public static final Instruction ICONST_1 = new ICONST(1);
51      public static final Instruction ICONST_2 = new ICONST(2);
52      public static final Instruction ICONST_3 = new ICONST(3);
53      public static final Instruction ICONST_4 = new ICONST(4);
54      public static final Instruction ICONST_5 = new ICONST(5);
55      public static final Instruction LCONST_0 = new LCONST(0);
56      public static final Instruction LCONST_1 = new LCONST(1);
57      public static final Instruction FCONST_0 = new FCONST(0);
58      public static final Instruction FCONST_1 = new FCONST(1);
59      public static final Instruction FCONST_2 = new FCONST(2);
60      public static final Instruction DCONST_0 = new DCONST(0);
61      public static final Instruction DCONST_1 = new DCONST(1);
62      public static final ArrayInstruction IALOADic/IALOAD.html#IALOAD">IALOAD = new IALOAD();
63      public static final ArrayInstruction LALOADic/LALOAD.html#LALOAD">LALOAD = new LALOAD();
64      public static final ArrayInstruction FALOADic/FALOAD.html#FALOAD">FALOAD = new FALOAD();
65      public static final ArrayInstruction DALOADic/DALOAD.html#DALOAD">DALOAD = new DALOAD();
66      public static final ArrayInstruction AALOADic/AALOAD.html#AALOAD">AALOAD = new AALOAD();
67      public static final ArrayInstruction BALOADic/BALOAD.html#BALOAD">BALOAD = new BALOAD();
68      public static final ArrayInstruction CALOADic/CALOAD.html#CALOAD">CALOAD = new CALOAD();
69      public static final ArrayInstruction SALOADic/SALOAD.html#SALOAD">SALOAD = new SALOAD();
70      public static final ArrayInstruction IASTOREc/IASTORE.html#IASTORE">IASTORE = new IASTORE();
71      public static final ArrayInstruction LASTOREc/LASTORE.html#LASTORE">LASTORE = new LASTORE();
72      public static final ArrayInstruction FASTOREc/FASTORE.html#FASTORE">FASTORE = new FASTORE();
73      public static final ArrayInstruction DASTOREc/DASTORE.html#DASTORE">DASTORE = new DASTORE();
74      public static final ArrayInstruction AASTOREc/AASTORE.html#AASTORE">AASTORE = new AASTORE();
75      public static final ArrayInstruction BASTOREc/BASTORE.html#BASTORE">BASTORE = new BASTORE();
76      public static final ArrayInstruction CASTOREc/CASTORE.html#CASTORE">CASTORE = new CASTORE();
77      public static final ArrayInstruction SASTOREc/SASTORE.html#SASTORE">SASTORE = new SASTORE();
78      public static final StackInstruction POPneric/POP.html#POP">POP = new POP();
79      public static final StackInstruction POP2eric/POP2.html#POP2">POP2 = new POP2();
80      public static final StackInstruction DUPneric/DUP.html#DUP">DUP = new DUP();
81      public static final StackInstruction DUP_X1ic/DUP_X1.html#DUP_X1">DUP_X1 = new DUP_X1();
82      public static final StackInstruction DUP_X2ic/DUP_X2.html#DUP_X2">DUP_X2 = new DUP_X2();
83      public static final StackInstruction DUP2eric/DUP2.html#DUP2">DUP2 = new DUP2();
84      public static final StackInstruction DUP2_X1c/DUP2_X1.html#DUP2_X1">DUP2_X1 = new DUP2_X1();
85      public static final StackInstruction DUP2_X2c/DUP2_X2.html#DUP2_X2">DUP2_X2 = new DUP2_X2();
86      public static final StackInstruction SWAPeric/SWAP.html#SWAP">SWAP = new SWAP();
87      public static final ArithmeticInstruction IADDeric/IADD.html#IADD">IADD = new IADD();
88      public static final ArithmeticInstruction LADDeric/LADD.html#LADD">LADD = new LADD();
89      public static final ArithmeticInstruction FADDeric/FADD.html#FADD">FADD = new FADD();
90      public static final ArithmeticInstruction DADDeric/DADD.html#DADD">DADD = new DADD();
91      public static final ArithmeticInstruction ISUBeric/ISUB.html#ISUB">ISUB = new ISUB();
92      public static final ArithmeticInstruction LSUBeric/LSUB.html#LSUB">LSUB = new LSUB();
93      public static final ArithmeticInstruction FSUBeric/FSUB.html#FSUB">FSUB = new FSUB();
94      public static final ArithmeticInstruction DSUBeric/DSUB.html#DSUB">DSUB = new DSUB();
95      public static final ArithmeticInstruction IMULeric/IMUL.html#IMUL">IMUL = new IMUL();
96      public static final ArithmeticInstruction LMULeric/LMUL.html#LMUL">LMUL = new LMUL();
97      public static final ArithmeticInstruction FMULeric/FMUL.html#FMUL">FMUL = new FMUL();
98      public static final ArithmeticInstruction DMULeric/DMUL.html#DMUL">DMUL = new DMUL();
99      public static final ArithmeticInstruction IDIVeric/IDIV.html#IDIV">IDIV = new IDIV();
100     public static final ArithmeticInstruction LDIVeric/LDIV.html#LDIV">LDIV = new LDIV();
101     public static final ArithmeticInstruction FDIVeric/FDIV.html#FDIV">FDIV = new FDIV();
102     public static final ArithmeticInstruction DDIVeric/DDIV.html#DDIV">DDIV = new DDIV();
103     public static final ArithmeticInstruction IREMeric/IREM.html#IREM">IREM = new IREM();
104     public static final ArithmeticInstruction LREMeric/LREM.html#LREM">LREM = new LREM();
105     public static final ArithmeticInstruction FREMeric/FREM.html#FREM">FREM = new FREM();
106     public static final ArithmeticInstruction DREMeric/DREM.html#DREM">DREM = new DREM();
107     public static final ArithmeticInstruction INEGeric/INEG.html#INEG">INEG = new INEG();
108     public static final ArithmeticInstruction LNEGeric/LNEG.html#LNEG">LNEG = new LNEG();
109     public static final ArithmeticInstruction FNEGeric/FNEG.html#FNEG">FNEG = new FNEG();
110     public static final ArithmeticInstruction DNEGeric/DNEG.html#DNEG">DNEG = new DNEG();
111     public static final ArithmeticInstruction ISHLeric/ISHL.html#ISHL">ISHL = new ISHL();
112     public static final ArithmeticInstruction LSHLeric/LSHL.html#LSHL">LSHL = new LSHL();
113     public static final ArithmeticInstruction ISHReric/ISHR.html#ISHR">ISHR = new ISHR();
114     public static final ArithmeticInstruction LSHReric/LSHR.html#LSHR">LSHR = new LSHR();
115     public static final ArithmeticInstruction IUSHRric/IUSHR.html#IUSHR">IUSHR = new IUSHR();
116     public static final ArithmeticInstruction LUSHRric/LUSHR.html#LUSHR">LUSHR = new LUSHR();
117     public static final ArithmeticInstruction IANDeric/IAND.html#IAND">IAND = new IAND();
118     public static final ArithmeticInstruction LANDeric/LAND.html#LAND">LAND = new LAND();
119     public static final ArithmeticInstruction IORneric/IOR.html#IOR">IOR = new IOR();
120     public static final ArithmeticInstruction LORneric/LOR.html#LOR">LOR = new LOR();
121     public static final ArithmeticInstruction IXOReric/IXOR.html#IXOR">IXOR = new IXOR();
122     public static final ArithmeticInstruction LXOReric/LXOR.html#LXOR">LXOR = new LXOR();
123     public static final ConversionInstruction I2Lneric/I2L.html#I2L">I2L = new I2L();
124     public static final ConversionInstruction I2Fneric/I2F.html#I2F">I2F = new I2F();
125     public static final ConversionInstruction I2Dneric/I2D.html#I2D">I2D = new I2D();
126     public static final ConversionInstruction L2Ineric/L2I.html#L2I">L2I = new L2I();
127     public static final ConversionInstruction L2Fneric/L2F.html#L2F">L2F = new L2F();
128     public static final ConversionInstruction L2Dneric/L2D.html#L2D">L2D = new L2D();
129     public static final ConversionInstruction F2Ineric/F2I.html#F2I">F2I = new F2I();
130     public static final ConversionInstruction F2Lneric/F2L.html#F2L">F2L = new F2L();
131     public static final ConversionInstruction F2Dneric/F2D.html#F2D">F2D = new F2D();
132     public static final ConversionInstruction D2Ineric/D2I.html#D2I">D2I = new D2I();
133     public static final ConversionInstruction D2Lneric/D2L.html#D2L">D2L = new D2L();
134     public static final ConversionInstruction D2Fneric/D2F.html#D2F">D2F = new D2F();
135     public static final ConversionInstruction I2Bneric/I2B.html#I2B">I2B = new I2B();
136     public static final ConversionInstruction I2Cneric/I2C.html#I2C">I2C = new I2C();
137     public static final ConversionInstruction I2Sneric/I2S.html#I2S">I2S = new I2S();
138     public static final Instruction LCMPeric/LCMP.html#LCMP">LCMP = new LCMP();
139     public static final Instruction FCMPLric/FCMPL.html#FCMPL">FCMPL = new FCMPL();
140     public static final Instruction FCMPGric/FCMPG.html#FCMPG">FCMPG = new FCMPG();
141     public static final Instruction DCMPLric/DCMPL.html#DCMPL">DCMPL = new DCMPL();
142     public static final Instruction DCMPGric/DCMPG.html#DCMPG">DCMPG = new DCMPG();
143     public static final ReturnInstruction IRETURNc/IRETURN.html#IRETURN">IRETURN = new IRETURN();
144     public static final ReturnInstruction LRETURNc/LRETURN.html#LRETURN">LRETURN = new LRETURN();
145     public static final ReturnInstruction FRETURNc/FRETURN.html#FRETURN">FRETURN = new FRETURN();
146     public static final ReturnInstruction DRETURNc/DRETURN.html#DRETURN">DRETURN = new DRETURN();
147     public static final ReturnInstruction ARETURNc/ARETURN.html#ARETURN">ARETURN = new ARETURN();
148     public static final ReturnInstruction RETURNic/RETURN.html#RETURN">RETURN = new RETURN();
149     public static final Instruction ARRAYLENGTHRAYLENGTH.html#ARRAYLENGTH">ARRAYLENGTH = new ARRAYLENGTH();
150     public static final Instruction ATHROWic/ATHROW.html#ATHROW">ATHROW = new ATHROW();
151     public static final Instruction MONITORENTERITORENTER.html#MONITORENTER">MONITORENTER = new MONITORENTER();
152     public static final Instruction MONITOREXITNITOREXIT.html#MONITOREXIT">MONITOREXIT = new MONITOREXIT();
153 
154     /** You can use these constants in multiple places safely, if you can guarantee
155      * that you will never alter their internal values, e.g. call setIndex().
156      */
157     public static final LocalVariableInstruction THIS = new ALOAD(0);
158     public static final LocalVariableInstruction ALOAD_0 = THIS;
159     public static final LocalVariableInstruction ALOAD_1 = new ALOAD(1);
160     public static final LocalVariableInstruction ALOAD_2 = new ALOAD(2);
161     public static final LocalVariableInstruction ILOAD_0 = new ILOAD(0);
162     public static final LocalVariableInstruction ILOAD_1 = new ILOAD(1);
163     public static final LocalVariableInstruction ILOAD_2 = new ILOAD(2);
164     public static final LocalVariableInstruction ASTORE_0 = new ASTORE(0);
165     public static final LocalVariableInstruction ASTORE_1 = new ASTORE(1);
166     public static final LocalVariableInstruction ASTORE_2 = new ASTORE(2);
167     public static final LocalVariableInstruction ISTORE_0 = new ISTORE(0);
168     public static final LocalVariableInstruction ISTORE_1 = new ISTORE(1);
169     public static final LocalVariableInstruction ISTORE_2 = new ISTORE(2);
170 
171     /** Get object via its opcode, for immutable instructions like
172      * branch instructions entries are set to null.
173      */
174     private static final InstructionInstruction">Instruction[] INSTRUCTIONS = new Instruction[256];
175 
176     static {
177         INSTRUCTIONS[Const.NOP] = NOP;
178         INSTRUCTIONS[Const.ACONST_NULL] = ACONST_NULL;
179         INSTRUCTIONS[Const.ICONST_M1] = ICONST_M1;
180         INSTRUCTIONS[Const.ICONST_0] = ICONST_0;
181         INSTRUCTIONS[Const.ICONST_1] = ICONST_1;
182         INSTRUCTIONS[Const.ICONST_2] = ICONST_2;
183         INSTRUCTIONS[Const.ICONST_3] = ICONST_3;
184         INSTRUCTIONS[Const.ICONST_4] = ICONST_4;
185         INSTRUCTIONS[Const.ICONST_5] = ICONST_5;
186         INSTRUCTIONS[Const.LCONST_0] = LCONST_0;
187         INSTRUCTIONS[Const.LCONST_1] = LCONST_1;
188         INSTRUCTIONS[Const.FCONST_0] = FCONST_0;
189         INSTRUCTIONS[Const.FCONST_1] = FCONST_1;
190         INSTRUCTIONS[Const.FCONST_2] = FCONST_2;
191         INSTRUCTIONS[Const.DCONST_0] = DCONST_0;
192         INSTRUCTIONS[Const.DCONST_1] = DCONST_1;
193         INSTRUCTIONS[Const.IALOAD] = IALOAD;
194         INSTRUCTIONS[Const.LALOAD] = LALOAD;
195         INSTRUCTIONS[Const.FALOAD] = FALOAD;
196         INSTRUCTIONS[Const.DALOAD] = DALOAD;
197         INSTRUCTIONS[Const.AALOAD] = AALOAD;
198         INSTRUCTIONS[Const.BALOAD] = BALOAD;
199         INSTRUCTIONS[Const.CALOAD] = CALOAD;
200         INSTRUCTIONS[Const.SALOAD] = SALOAD;
201         INSTRUCTIONS[Const.IASTORE] = IASTORE;
202         INSTRUCTIONS[Const.LASTORE] = LASTORE;
203         INSTRUCTIONS[Const.FASTORE] = FASTORE;
204         INSTRUCTIONS[Const.DASTORE] = DASTORE;
205         INSTRUCTIONS[Const.AASTORE] = AASTORE;
206         INSTRUCTIONS[Const.BASTORE] = BASTORE;
207         INSTRUCTIONS[Const.CASTORE] = CASTORE;
208         INSTRUCTIONS[Const.SASTORE] = SASTORE;
209         INSTRUCTIONS[Const.POP] = POP;
210         INSTRUCTIONS[Const.POP2] = POP2;
211         INSTRUCTIONS[Const.DUP] = DUP;
212         INSTRUCTIONS[Const.DUP_X1] = DUP_X1;
213         INSTRUCTIONS[Const.DUP_X2] = DUP_X2;
214         INSTRUCTIONS[Const.DUP2] = DUP2;
215         INSTRUCTIONS[Const.DUP2_X1] = DUP2_X1;
216         INSTRUCTIONS[Const.DUP2_X2] = DUP2_X2;
217         INSTRUCTIONS[Const.SWAP] = SWAP;
218         INSTRUCTIONS[Const.IADD] = IADD;
219         INSTRUCTIONS[Const.LADD] = LADD;
220         INSTRUCTIONS[Const.FADD] = FADD;
221         INSTRUCTIONS[Const.DADD] = DADD;
222         INSTRUCTIONS[Const.ISUB] = ISUB;
223         INSTRUCTIONS[Const.LSUB] = LSUB;
224         INSTRUCTIONS[Const.FSUB] = FSUB;
225         INSTRUCTIONS[Const.DSUB] = DSUB;
226         INSTRUCTIONS[Const.IMUL] = IMUL;
227         INSTRUCTIONS[Const.LMUL] = LMUL;
228         INSTRUCTIONS[Const.FMUL] = FMUL;
229         INSTRUCTIONS[Const.DMUL] = DMUL;
230         INSTRUCTIONS[Const.IDIV] = IDIV;
231         INSTRUCTIONS[Const.LDIV] = LDIV;
232         INSTRUCTIONS[Const.FDIV] = FDIV;
233         INSTRUCTIONS[Const.DDIV] = DDIV;
234         INSTRUCTIONS[Const.IREM] = IREM;
235         INSTRUCTIONS[Const.LREM] = LREM;
236         INSTRUCTIONS[Const.FREM] = FREM;
237         INSTRUCTIONS[Const.DREM] = DREM;
238         INSTRUCTIONS[Const.INEG] = INEG;
239         INSTRUCTIONS[Const.LNEG] = LNEG;
240         INSTRUCTIONS[Const.FNEG] = FNEG;
241         INSTRUCTIONS[Const.DNEG] = DNEG;
242         INSTRUCTIONS[Const.ISHL] = ISHL;
243         INSTRUCTIONS[Const.LSHL] = LSHL;
244         INSTRUCTIONS[Const.ISHR] = ISHR;
245         INSTRUCTIONS[Const.LSHR] = LSHR;
246         INSTRUCTIONS[Const.IUSHR] = IUSHR;
247         INSTRUCTIONS[Const.LUSHR] = LUSHR;
248         INSTRUCTIONS[Const.IAND] = IAND;
249         INSTRUCTIONS[Const.LAND] = LAND;
250         INSTRUCTIONS[Const.IOR] = IOR;
251         INSTRUCTIONS[Const.LOR] = LOR;
252         INSTRUCTIONS[Const.IXOR] = IXOR;
253         INSTRUCTIONS[Const.LXOR] = LXOR;
254         INSTRUCTIONS[Const.I2L] = I2L;
255         INSTRUCTIONS[Const.I2F] = I2F;
256         INSTRUCTIONS[Const.I2D] = I2D;
257         INSTRUCTIONS[Const.L2I] = L2I;
258         INSTRUCTIONS[Const.L2F] = L2F;
259         INSTRUCTIONS[Const.L2D] = L2D;
260         INSTRUCTIONS[Const.F2I] = F2I;
261         INSTRUCTIONS[Const.F2L] = F2L;
262         INSTRUCTIONS[Const.F2D] = F2D;
263         INSTRUCTIONS[Const.D2I] = D2I;
264         INSTRUCTIONS[Const.D2L] = D2L;
265         INSTRUCTIONS[Const.D2F] = D2F;
266         INSTRUCTIONS[Const.I2B] = I2B;
267         INSTRUCTIONS[Const.I2C] = I2C;
268         INSTRUCTIONS[Const.I2S] = I2S;
269         INSTRUCTIONS[Const.LCMP] = LCMP;
270         INSTRUCTIONS[Const.FCMPL] = FCMPL;
271         INSTRUCTIONS[Const.FCMPG] = FCMPG;
272         INSTRUCTIONS[Const.DCMPL] = DCMPL;
273         INSTRUCTIONS[Const.DCMPG] = DCMPG;
274         INSTRUCTIONS[Const.IRETURN] = IRETURN;
275         INSTRUCTIONS[Const.LRETURN] = LRETURN;
276         INSTRUCTIONS[Const.FRETURN] = FRETURN;
277         INSTRUCTIONS[Const.DRETURN] = DRETURN;
278         INSTRUCTIONS[Const.ARETURN] = ARETURN;
279         INSTRUCTIONS[Const.RETURN] = RETURN;
280         INSTRUCTIONS[Const.ARRAYLENGTH] = ARRAYLENGTH;
281         INSTRUCTIONS[Const.ATHROW] = ATHROW;
282         INSTRUCTIONS[Const.MONITORENTER] = MONITORENTER;
283         INSTRUCTIONS[Const.MONITOREXIT] = MONITOREXIT;
284     }
285 
286     private InstructionConst() { } // non-instantiable
287 
288     /**
289      * Gets the Instruction.
290      * @param index the index, e.g. {@link Const#RETURN}
291      * @return the entry from the private INSTRUCTIONS table
292      */
293     public static Instruction getInstruction(final int index) {
294         return INSTRUCTIONS[index];
295     }
296 }