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src/java.xml/share/classes/com/sun/org/apache/bcel/internal/util/InstructionFinder.java

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   1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 package com.sun.org.apache.bcel.internal.util;
   6 
   7 /*
   8  * Licensed to the Apache Software Foundation (ASF) under one or more
   9  * contributor license agreements.  See the NOTICE file distributed with
  10  * this work for additional information regarding copyright ownership.
  11  * The ASF licenses this file to You under the Apache License, Version 2.0
  12  * (the "License"); you may not use this file except in compliance with
  13  * the License.  You may obtain a copy of the License at
  14  *
  15  *      http://www.apache.org/licenses/LICENSE-2.0
  16  *
  17  *  Unless required by applicable law or agreed to in writing, software
  18  *  distributed under the License is distributed on an "AS IS" BASIS,
  19  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  20  *  See the License for the specific language governing permissions and
  21  *  limitations under the License.
  22  *
  23  */
  24 
  25 import com.sun.org.apache.bcel.internal.Constants;
  26 import com.sun.org.apache.bcel.internal.generic.*;
  27 import java.util.*;
  28 import java.util.regex.Matcher;
  29 import java.util.regex.Pattern;
  30 





  31 /**
  32  * InstructionFinder is a tool to search for given instructions patterns,
  33  * i.e., match sequences of instructions in an instruction list via
  34  * regular expressions. This can be used, e.g., in order to implement
  35  * a peep hole optimizer that looks for code patterns and replaces
  36  * them with faster equivalents.
  37  *
  38  * <p>This class internally uses the <a href="http://jakarta.apache.org/regexp/">
  39  * Regexp</a> package to search for regular expressions.

  40  *
  41  * A typical application would look like this:
  42 <pre>
  43     InstructionFinder f   = new InstructionFinder(il);
  44     String            pat = "IfInstruction ICONST_0 GOTO ICONST_1 NOP (IFEQ|IFNE)";
  45 
  46     for(Iterator i = f.search(pat, constraint); i.hasNext(); ) {
  47       InstructionHandle[] match = (InstructionHandle[])i.next();
  48       ...
  49       il.delete(match[1], match[5]);
  50       ...
  51     }
  52 </pre>
  53  * @author  <A HREF="http://www.berlin.de/~markus.dahm/">M. Dahm</A>
  54  * @see Instruction






  55  * @see InstructionList
  56  */
  57 public class InstructionFinder {

  58   private static final int OFFSET     = 32767; // char + OFFSET is outside of LATIN-1
  59   private static final int NO_OPCODES = 256;   // Potential number, some are not used
  60 
  61   private static final HashMap map = new HashMap(); // Map<String,Pattern>
  62 
  63   private InstructionList     il;
  64   private String              il_string;    // instruction list as string
  65   private InstructionHandle[] handles;      // map instruction list to array

  66 

  67   /**
  68    * @param il instruction list to search for given patterns

  69    */
  70   public InstructionFinder(InstructionList il) {
  71     this.il = il;
  72     reread();
  73   }
  74 

  75   /**
  76    * Reread the instruction list, e.g., after you've altered the list upon a match.

  77    */
  78   public final void reread() {
  79     int    size  = il.getLength();
  80     char[] buf   = new char[size]; // Create a string with length equal to il length
  81     handles      = il.getInstructionHandles();
  82 
  83     // Map opcodes to characters
  84     for(int i=0; i < size; i++)
  85       buf[i] = makeChar(handles[i].getInstruction().getOpcode());
  86 
  87     il_string = new String(buf);
  88   }
  89 

  90   /**
  91    * Map symbolic instruction names like "getfield" to a single character.
  92    *
  93    * @param pattern instruction pattern in lower case

  94    * @return encoded string for a pattern such as "BranchInstruction".
  95    */
  96   private static final String mapName(String pattern) {
  97     String result = (String)map.get(pattern);
  98 
  99     if(result != null)
 100       return result;
 101 
 102     for(short i=0; i < NO_OPCODES; i++)
 103       if(pattern.equals(Constants.OPCODE_NAMES[i]))
 104         return "" + makeChar(i);
 105 

 106     throw new RuntimeException("Instruction unknown: " + pattern);
 107   }
 108 

 109   /**
 110    * Replace symbolic names of instructions with the appropiate character and remove
 111    * all white space from string. Meta characters such as +, * are ignored.

 112    *
 113    * @param pattern The pattern to compile

 114    * @return translated regular expression string
 115    */
 116   private static final String compilePattern(String pattern) {
 117     String       lower      = pattern.toLowerCase();
 118     StringBuffer buf        = new StringBuffer();
 119     int          size       = pattern.length();
 120 
 121     for(int i=0; i < size; i++) {
 122       char ch = lower.charAt(i);
 123 
 124       if(Character.isLetterOrDigit(ch)) {
 125         StringBuffer name = new StringBuffer();
 126 
 127         while((Character.isLetterOrDigit(ch) || ch == '_') && i < size) {
 128           name.append(ch);
 129 
 130           if(++i < size)
 131             ch = lower.charAt(i);
 132           else
 133             break;
 134         }
 135 
 136         i--;
 137 
 138         buf.append(mapName(name.toString()));
 139       } else if(!Character.isWhitespace(ch))
 140         buf.append(ch);
 141     }
 142 
 143     return buf.toString();
 144   }
 145 

 146   /**
 147    * @return the matched piece of code as an array of instruction (handles)
 148    */
 149   private InstructionHandle[] getMatch(int matched_from, int match_length) {
 150     InstructionHandle[] match = new InstructionHandle[match_length];
 151     System.arraycopy(handles, matched_from, match, 0, match_length);
 152 
 153     return match;
 154   }
 155 

 156   /**
 157    * Search for the given pattern in the instruction list. You can search for any valid
 158    * opcode via its symbolic name, e.g. "istore". You can also use a super class or
 159    * an interface name to match a whole set of instructions, e.g. "BranchInstruction" or
 160    * "LoadInstruction". "istore" is also an alias for all "istore_x" instructions. Additional
 161    * aliases are "if" for "ifxx", "if_icmp" for "if_icmpxx", "if_acmp" for "if_acmpxx".
 162    *
 163    * Consecutive instruction names must be separated by white space which will be removed
 164    * during the compilation of the pattern.
 165    *
 166    * For the rest the usual pattern matching rules for regular expressions apply.<P>



 167    * Example pattern:

 168    * <pre>
 169      search("BranchInstruction NOP ((IfInstruction|GOTO)+ ISTORE Instruction)*");
 170    * </pre>
 171    *
 172    * <p>If you alter the instruction list upon a match such that other
 173    * matching areas are affected, you should call reread() to update
 174    * the finder and call search() again, because the matches are cached.
 175    *
 176    * @param pattern the instruction pattern to search for, where case is ignored
 177    * @param from where to start the search in the instruction list
 178    * @param constraint optional CodeConstraint to check the found code pattern for




 179    * user-defined constraints
 180    * @return iterator of matches where e.nextElement() returns an array of instruction handles
 181    * describing the matched area
 182    */
 183   public final Iterator search(String pattern, InstructionHandle from,
 184                                CodeConstraint constraint)
 185   {
 186     String search = compilePattern(pattern);
 187     int  start    = -1;
 188 
 189     for(int i=0; i < handles.length; i++) {
 190       if(handles[i] == from) {
 191         start = i; // Where to start search from (index)
 192         break;
 193       }
 194     }
 195 
 196     if(start == -1)
 197       throw new ClassGenException("Instruction handle " + from +
 198                                   " not found in instruction list.");
 199 
 200     Pattern regex = Pattern.compile(search);
 201     List<InstructionHandle[]> matches = new ArrayList<>();
 202     Matcher matcher = regex.matcher(il_string);
 203     while(start < il_string.length() && matcher.find(start)) {
 204       int startExpr = matcher.start();
 205       int endExpr   = matcher.end();
 206       int lenExpr   = endExpr - startExpr;
 207       InstructionHandle[] match = getMatch(startExpr, lenExpr);
 208 
 209       if((constraint == null) || constraint.checkCode(match))
 210         matches.add(match);

 211       start = endExpr;
 212     }
 213 
 214     return matches.iterator();
 215   }
 216 

 217   /**
 218    * Start search beginning from the start of the given instruction list.
 219    *
 220    * @param pattern the instruction pattern to search for, where case is ignored
 221    * @return iterator of matches where e.nextElement()
 222    * returns an array of instruction handles describing the matched
 223    * area
 224    */
 225   public final Iterator search(String pattern) {
 226     return search(pattern, il.getStart(), null);
 227   }
 228 

 229   /**
 230    * Start search beginning from `from'.
 231    *
 232    * @param pattern the instruction pattern to search for, where case is ignored
 233    * @param from where to start the search in the instruction list
 234    * @return  iterator of matches where e.nextElement() returns an array of instruction handles
 235    * describing the matched area


 236    */
 237   public final Iterator search(String pattern, InstructionHandle from) {

 238     return search(pattern, from, null);
 239   }
 240 

 241   /**
 242    * Start search beginning from the start of the given instruction list.
 243    * Check found matches with the constraint object.
 244    *
 245    * @param pattern the instruction pattern to search for, case is ignored
 246    * @param constraint constraints to be checked on matching code


 247    * @return instruction handle or `null' if the match failed
 248    */
 249   public final Iterator search(String pattern, CodeConstraint constraint) {

 250     return search(pattern, il.getStart(), constraint);
 251   }
 252 

 253   /**
 254    * Convert opcode number to char.
 255    */
 256   private static final char makeChar(short opcode) {
 257     return (char)(opcode + OFFSET);
 258   }
 259 

 260   /**
 261    * @return the inquired instruction list
 262    */
 263   public final InstructionList getInstructionList() { return il; }


 264 
 265   /**
 266    * Code patterns found may be checked using an additional
 267    * user-defined constraint object whether they really match the needed criterion.
 268    * I.e., check constraints that can not expressed with regular expressions.
 269    *
 270    */
 271   public interface CodeConstraint {

 272     /**
 273      * @param match array of instructions matching the requested pattern

 274      * @return true if the matched area is really useful
 275      */
 276     public boolean checkCode(InstructionHandle[] match);
 277   }
 278 
 279   // Initialize pattern map
 280 
 281   static {
 282     map.put("arithmeticinstruction", "(irem|lrem|iand|ior|ineg|isub|lneg|fneg|fmul|ldiv|fadd|lxor|frem|idiv|land|ixor|ishr|fsub|lshl|fdiv|iadd|lor|dmul|lsub|ishl|imul|lmul|lushr|dneg|iushr|lshr|ddiv|drem|dadd|ladd|dsub)");
 283     map.put("invokeinstruction", "(invokevirtual|invokeinterface|invokestatic|invokespecial)");
 284     map.put("arrayinstruction", "(baload|aastore|saload|caload|fastore|lastore|iaload|castore|iastore|aaload|bastore|sastore|faload|laload|daload|dastore)");
 285     map.put("gotoinstruction", "(goto|goto_w)");
 286     map.put("conversioninstruction", "(d2l|l2d|i2s|d2i|l2i|i2b|l2f|d2f|f2i|i2d|i2l|f2d|i2c|f2l|i2f)");
 287     map.put("localvariableinstruction", "(fstore|iinc|lload|dstore|dload|iload|aload|astore|istore|fload|lstore)");
 288     map.put("loadinstruction", "(fload|dload|lload|iload|aload)");
 289     map.put("fieldinstruction", "(getfield|putstatic|getstatic|putfield)");
 290     map.put("cpinstruction", "(ldc2_w|invokeinterface|multianewarray|putstatic|instanceof|getstatic|checkcast|getfield|invokespecial|ldc_w|invokestatic|invokevirtual|putfield|ldc|new|anewarray)");
 291     map.put("stackinstruction", "(dup2|swap|dup2_x2|pop|pop2|dup|dup2_x1|dup_x2|dup_x1)");
 292     map.put("branchinstruction", "(ifle|if_acmpne|if_icmpeq|if_acmpeq|ifnonnull|goto_w|iflt|ifnull|if_icmpne|tableswitch|if_icmple|ifeq|if_icmplt|jsr_w|if_icmpgt|ifgt|jsr|goto|ifne|ifge|lookupswitch|if_icmpge)");
 293     map.put("returninstruction", "(lreturn|ireturn|freturn|dreturn|areturn|return)");
 294     map.put("storeinstruction", "(istore|fstore|dstore|astore|lstore)");
 295     map.put("select", "(tableswitch|lookupswitch)");
 296     map.put("ifinstruction", "(ifeq|ifgt|if_icmpne|if_icmpeq|ifge|ifnull|ifne|if_icmple|if_icmpge|if_acmpeq|if_icmplt|if_acmpne|ifnonnull|iflt|if_icmpgt|ifle)");
 297     map.put("jsrinstruction", "(jsr|jsr_w)");
 298     map.put("variablelengthinstruction", "(tableswitch|jsr|goto|lookupswitch)");
 299     map.put("unconditionalbranch", "(goto|jsr|jsr_w|athrow|goto_w)");
 300     map.put("constantpushinstruction", "(dconst|bipush|sipush|fconst|iconst|lconst)");
 301     map.put("typedinstruction", "(imul|lsub|aload|fload|lor|new|aaload|fcmpg|iand|iaload|lrem|idiv|d2l|isub|dcmpg|dastore|ret|f2d|f2i|drem|iinc|i2c|checkcast|frem|lreturn|astore|lushr|daload|dneg|fastore|istore|lshl|ldiv|lstore|areturn|ishr|ldc_w|invokeinterface|aastore|lxor|ishl|l2d|i2f|return|faload|sipush|iushr|caload|instanceof|invokespecial|putfield|fmul|ireturn|laload|d2f|lneg|ixor|i2l|fdiv|lastore|multianewarray|i2b|getstatic|i2d|putstatic|fcmpl|saload|ladd|irem|dload|jsr_w|dconst|dcmpl|fsub|freturn|ldc|aconst_null|castore|lmul|ldc2_w|dadd|iconst|f2l|ddiv|dstore|land|jsr|anewarray|dmul|bipush|dsub|sastore|d2i|i2s|lshr|iadd|l2i|lload|bastore|fstore|fneg|iload|fadd|baload|fconst|ior|ineg|dreturn|l2f|lconst|getfield|invokevirtual|invokestatic|iastore)");
 302     map.put("popinstruction", "(fstore|dstore|pop|pop2|astore|putstatic|istore|lstore)");
 303     map.put("allocationinstruction", "(multianewarray|new|anewarray|newarray)");
 304     map.put("indexedinstruction", "(lload|lstore|fload|ldc2_w|invokeinterface|multianewarray|astore|dload|putstatic|instanceof|getstatic|checkcast|getfield|invokespecial|dstore|istore|iinc|ldc_w|ret|fstore|invokestatic|iload|putfield|invokevirtual|ldc|new|aload|anewarray)");
 305     map.put("pushinstruction", "(dup|lload|dup2|bipush|fload|ldc2_w|sipush|lconst|fconst|dload|getstatic|ldc_w|aconst_null|dconst|iload|ldc|iconst|aload)");
 306     map.put("stackproducer", "(imul|lsub|aload|fload|lor|new|aaload|fcmpg|iand|iaload|lrem|idiv|d2l|isub|dcmpg|dup|f2d|f2i|drem|i2c|checkcast|frem|lushr|daload|dneg|lshl|ldiv|ishr|ldc_w|invokeinterface|lxor|ishl|l2d|i2f|faload|sipush|iushr|caload|instanceof|invokespecial|fmul|laload|d2f|lneg|ixor|i2l|fdiv|getstatic|i2b|swap|i2d|dup2|fcmpl|saload|ladd|irem|dload|jsr_w|dconst|dcmpl|fsub|ldc|arraylength|aconst_null|tableswitch|lmul|ldc2_w|iconst|dadd|f2l|ddiv|land|jsr|anewarray|dmul|bipush|dsub|d2i|newarray|i2s|lshr|iadd|lload|l2i|fneg|iload|fadd|baload|fconst|lookupswitch|ior|ineg|lconst|l2f|getfield|invokevirtual|invokestatic)");
 307     map.put("stackconsumer", "(imul|lsub|lor|iflt|fcmpg|if_icmpgt|iand|ifeq|if_icmplt|lrem|ifnonnull|idiv|d2l|isub|dcmpg|dastore|if_icmpeq|f2d|f2i|drem|i2c|checkcast|frem|lreturn|astore|lushr|pop2|monitorexit|dneg|fastore|istore|lshl|ldiv|lstore|areturn|if_icmpge|ishr|monitorenter|invokeinterface|aastore|lxor|ishl|l2d|i2f|return|iushr|instanceof|invokespecial|fmul|ireturn|d2f|lneg|ixor|pop|i2l|ifnull|fdiv|lastore|i2b|if_acmpeq|ifge|swap|i2d|putstatic|fcmpl|ladd|irem|dcmpl|fsub|freturn|ifgt|castore|lmul|dadd|f2l|ddiv|dstore|land|if_icmpne|if_acmpne|dmul|dsub|sastore|ifle|d2i|i2s|lshr|iadd|l2i|bastore|fstore|fneg|fadd|ior|ineg|ifne|dreturn|l2f|if_icmple|getfield|invokevirtual|invokestatic|iastore)");
 308     map.put("exceptionthrower", "(irem|lrem|laload|putstatic|baload|dastore|areturn|getstatic|ldiv|anewarray|iastore|castore|idiv|saload|lastore|fastore|putfield|lreturn|caload|getfield|return|aastore|freturn|newarray|instanceof|multianewarray|athrow|faload|iaload|aaload|dreturn|monitorenter|checkcast|bastore|arraylength|new|invokevirtual|sastore|ldc_w|ireturn|invokespecial|monitorexit|invokeinterface|ldc|invokestatic|daload)");
 309     map.put("loadclass", "(multianewarray|invokeinterface|instanceof|invokespecial|putfield|checkcast|putstatic|invokevirtual|new|getstatic|invokestatic|getfield|anewarray)");
 310     map.put("instructiontargeter", "(ifle|if_acmpne|if_icmpeq|if_acmpeq|ifnonnull|goto_w|iflt|ifnull|if_icmpne|tableswitch|if_icmple|ifeq|if_icmplt|jsr_w|if_icmpgt|ifgt|jsr|goto|ifne|ifge|lookupswitch|if_icmpge)");
 311 
 312     // Some aliases
 313     map.put("if_icmp", "(if_icmpne|if_icmpeq|if_icmple|if_icmpge|if_icmplt|if_icmpgt)");
 314     map.put("if_acmp", "(if_acmpeq|if_acmpne)");
 315     map.put("if", "(ifeq|ifne|iflt|ifge|ifgt|ifle)");
 316 
 317     // Precompile some aliases first
 318     map.put("iconst", precompile(Constants.ICONST_0, Constants.ICONST_5, Constants.ICONST_M1));
 319     map.put("lconst", new String(new char[] { '(', makeChar(Constants.LCONST_0), '|',
 320                                               makeChar(Constants.LCONST_1), ')' }));
 321     map.put("dconst", new String(new char[] { '(', makeChar(Constants.DCONST_0), '|',
 322                                               makeChar(Constants.DCONST_1), ')' }));
 323     map.put("fconst", new String(new char[] { '(', makeChar(Constants.FCONST_0), '|',
 324                                               makeChar(Constants.FCONST_1), ')' }));
 325 
 326     map.put("iload", precompile(Constants.ILOAD_0, Constants.ILOAD_3, Constants.ILOAD));
 327     map.put("dload", precompile(Constants.DLOAD_0, Constants.DLOAD_3, Constants.DLOAD));
 328     map.put("fload", precompile(Constants.FLOAD_0, Constants.FLOAD_3, Constants.FLOAD));
 329     map.put("aload", precompile(Constants.ALOAD_0, Constants.ALOAD_3, Constants.ALOAD));
 330 
 331     map.put("istore", precompile(Constants.ISTORE_0, Constants.ISTORE_3, Constants.ISTORE));
 332     map.put("dstore", precompile(Constants.DSTORE_0, Constants.DSTORE_3, Constants.DSTORE));
 333     map.put("fstore", precompile(Constants.FSTORE_0, Constants.FSTORE_3, Constants.FSTORE));
 334     map.put("astore", precompile(Constants.ASTORE_0, Constants.ASTORE_3, Constants.ASTORE));
 335 
 336     // Compile strings
 337 
 338     for(Iterator i = map.keySet().iterator(); i.hasNext(); ) {
 339       String key   = (String)i.next();
 340       String value = (String)map.get(key);
 341 
 342       char ch = value.charAt(1); // Omit already precompiled patterns
 343       if(ch < OFFSET) {
 344         map.put(key, compilePattern(value)); // precompile all patterns
 345       }
 346     }
 347 
 348     // Add instruction alias to match anything
 349 
 350     StringBuffer buf = new StringBuffer("(");
 351 
 352     for(short i=0; i < NO_OPCODES; i++) {
 353       if(Constants.NO_OF_OPERANDS[i] != Constants.UNDEFINED) { // Not an invalid opcode
 354         buf.append(makeChar(i));
 355 
 356         if(i < NO_OPCODES - 1)
 357           buf.append('|');
 358       }
 359     }

 360     buf.append(')');
 361 
 362     map.put("instruction", buf.toString());
 363   }
 364 
 365   private static String precompile(short from, short to, short extra) {
 366     StringBuffer buf = new StringBuffer("(");
 367 
 368     for(short i=from; i <= to; i++) {


 369       buf.append(makeChar(i));
 370       buf.append('|');
 371     }
 372 
 373     buf.append(makeChar(extra));
 374     buf.append(")");
 375     return buf.toString();
 376   }
 377 

 378   /*
 379    * Internal debugging routines.
 380    */
 381   private static final String pattern2string(String pattern) {
 382     return pattern2string(pattern, true);
 383   }
 384 
 385   private static final String pattern2string(String pattern, boolean make_string) {
 386     StringBuffer buf = new StringBuffer();
 387 
 388     for(int i=0; i < pattern.length(); i++) {
 389       char ch = pattern.charAt(i);
 390 
 391       if(ch >= OFFSET) {
 392         if(make_string)
 393           buf.append(Constants.OPCODE_NAMES[ch - OFFSET]);
 394         else
 395           buf.append((int)(ch - OFFSET));
 396       } else
 397         buf.append(ch);
 398     }
 399 
 400     return buf.toString();
 401   }
 402 }

   1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 package com.sun.org.apache.bcel.internal.util;
   6 
   7 import java.util.ArrayList;
   8 import java.util.HashMap;
   9 import java.util.Iterator;
  10 import java.util.List;
  11 import java.util.Locale;
  12 import java.util.Map;















  13 import java.util.regex.Matcher;
  14 import java.util.regex.Pattern;
  15 
  16 import com.sun.org.apache.bcel.internal.Const;
  17 import com.sun.org.apache.bcel.internal.generic.ClassGenException;
  18 import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
  19 import com.sun.org.apache.bcel.internal.generic.InstructionList;
  20 
  21 /**
  22  * InstructionFinder is a tool to search for given instructions patterns, i.e.,
  23  * match sequences of instructions in an instruction list via regular
  24  * expressions. This can be used, e.g., in order to implement a peep hole
  25  * optimizer that looks for code patterns and replaces them with faster
  26  * equivalents.
  27  *
  28  * <p>
  29  * This class internally uses the java.util.regex
  30  * package to search for regular expressions.
  31  *
  32  * A typical application would look like this:
  33  *
  34  * <pre>
  35  *
  36  *
  37  *   InstructionFinder f   = new InstructionFinder(il);
  38  *   String            pat = &quot;IfInstruction ICONST_0 GOTO ICONST_1 NOP (IFEQ|IFNE)&quot;;
  39  *
  40  *   for (Iterator i = f.search(pat, constraint); i.hasNext(); ) {
  41  *   InstructionHandle[] match = (InstructionHandle[])i.next();
  42  *   ...
  43  *   il.delete(match[1], match[5]);
  44  *   ...
  45  *   }
  46  *
  47  *
  48  * </pre>
  49  *
  50  * @version $Id: InstructionFinder.java 1749603 2016-06-21 20:50:19Z ggregory $
  51  * @see com.sun.org.apache.bcel.internal.generic.Instruction
  52  * @see InstructionList
  53  */
  54 public class InstructionFinder {
  55 
  56     private static final int OFFSET = 32767; // char + OFFSET is outside of LATIN-1
  57     private static final int NO_OPCODES = 256; // Potential number, some are not used
  58     private static final Map<String, String> map = new HashMap<>();
  59     private final InstructionList il;


  60     private String il_string; // instruction list as string
  61     private InstructionHandle[] handles; // map instruction
  62 
  63 
  64     // list to array
  65     /**
  66      * @param il
  67      *          instruction list to search for given patterns
  68      */
  69     public InstructionFinder(final InstructionList il) {
  70         this.il = il;
  71         reread();
  72     }
  73 
  74 
  75     /**
  76      * Reread the instruction list, e.g., after you've altered the list upon a
  77      * match.
  78      */
  79     public final void reread() {
  80         final int size = il.getLength();
  81         final char[] buf = new char[size]; // Create a string with length equal to il length
  82         handles = il.getInstructionHandles();

  83         // Map opcodes to characters
  84         for (int i = 0; i < size; i++) {
  85             buf[i] = makeChar(handles[i].getInstruction().getOpcode());
  86         }
  87         il_string = new String(buf);
  88     }
  89 
  90 
  91     /**
  92      * Map symbolic instruction names like "getfield" to a single character.
  93      *
  94      * @param pattern
  95      *          instruction pattern in lower case
  96      * @return encoded string for a pattern such as "BranchInstruction".
  97      */
  98     private static String mapName( final String pattern ) {
  99         final String result = map.get(pattern);
 100         if (result != null) {

 101             return result;
 102         }
 103         for (short i = 0; i < NO_OPCODES; i++) {
 104             if (pattern.equals(Const.getOpcodeName(i))) {
 105                 return "" + makeChar(i);
 106             }
 107         }
 108         throw new RuntimeException("Instruction unknown: " + pattern);
 109     }
 110 
 111 
 112     /**
 113      * Replace symbolic names of instructions with the appropiate character and
 114      * remove all white space from string. Meta characters such as +, * are
 115      * ignored.
 116      *
 117      * @param pattern
 118      *          The pattern to compile
 119      * @return translated regular expression string
 120      */
 121     private static String compilePattern( final String pattern ) {
 122         //Bug: BCEL-77 - Instructions are assumed to be english, to avoid odd Locale issues
 123         final String lower = pattern.toLowerCase(Locale.ENGLISH);
 124         final StringBuilder buf = new StringBuilder();
 125         final int size = pattern.length();
 126         for (int i = 0; i < size; i++) {
 127             char ch = lower.charAt(i);
 128             if (Character.isLetterOrDigit(ch)) {
 129                 final StringBuilder name = new StringBuilder();
 130                 while ((Character.isLetterOrDigit(ch) || ch == '_') && i < size) {


 131                     name.append(ch);
 132                     if (++i < size) {

 133                         ch = lower.charAt(i);
 134                     } else {
 135                         break;
 136                     }
 137                 }
 138                 i--;

 139                 buf.append(mapName(name.toString()));
 140             } else if (!Character.isWhitespace(ch)) {
 141                 buf.append(ch);
 142             }
 143         }
 144         return buf.toString();
 145     }
 146 
 147 
 148     /**
 149      * @return the matched piece of code as an array of instruction (handles)
 150      */
 151     private InstructionHandle[] getMatch( final int matched_from, final int match_length ) {
 152         final InstructionHandle[] match = new InstructionHandle[match_length];
 153         System.arraycopy(handles, matched_from, match, 0, match_length);

 154         return match;
 155     }
 156 
 157 
 158     /**
 159      * Search for the given pattern in the instruction list. You can search for
 160      * any valid opcode via its symbolic name, e.g. "istore". You can also use a
 161      * super class or an interface name to match a whole set of instructions, e.g.
 162      * "BranchInstruction" or "LoadInstruction". "istore" is also an alias for all
 163      * "istore_x" instructions. Additional aliases are "if" for "ifxx", "if_icmp"
 164      * for "if_icmpxx", "if_acmp" for "if_acmpxx".
 165      *
 166      * Consecutive instruction names must be separated by white space which will
 167      * be removed during the compilation of the pattern.
 168      *
 169      * For the rest the usual pattern matching rules for regular expressions
 170      * apply.
 171      * <P>
 172      * Example pattern:
 173      *
 174      * <pre>
 175      * search(&quot;BranchInstruction NOP ((IfInstruction|GOTO)+ ISTORE Instruction)*&quot;);
 176      * </pre>
 177      *
 178      * <p>
 179      * If you alter the instruction list upon a match such that other matching
 180      * areas are affected, you should call reread() to update the finder and call
 181      * search() again, because the matches are cached.
 182      *
 183      * @param pattern
 184      *          the instruction pattern to search for, where case is ignored
 185      * @param from
 186      *          where to start the search in the instruction list
 187      * @param constraint
 188      *          optional CodeConstraint to check the found code pattern for
 189      *          user-defined constraints
 190      * @return iterator of matches where e.nextElement() returns an array of
 191      *         instruction handles describing the matched area
 192      */
 193     public final Iterator<InstructionHandle[]> search( final String pattern,
 194             final InstructionHandle from, final CodeConstraint constraint ) {
 195         final String search = compilePattern(pattern);

 196         int start = -1;
 197         for (int i = 0; i < handles.length; i++) {
 198             if (handles[i] == from) {

 199                 start = i; // Where to start search from (index)
 200                 break;
 201             }
 202         }
 203         if (start == -1) {
 204             throw new ClassGenException("Instruction handle " + from
 205                     + " not found in instruction list.");
 206         }
 207         final Pattern regex = Pattern.compile(search);
 208         final List<InstructionHandle[]> matches = new ArrayList<>();
 209         final Matcher matcher = regex.matcher(il_string);
 210         while (start < il_string.length() && matcher.find(start)) {
 211             final int startExpr = matcher.start();
 212             final int endExpr = matcher.end();
 213             final int lenExpr = endExpr - startExpr;
 214             final InstructionHandle[] match = getMatch(startExpr, lenExpr);
 215             if ((constraint == null) || constraint.checkCode(match)) {


 216                 matches.add(match);
 217             }
 218             start = endExpr;
 219         }

 220         return matches.iterator();
 221     }
 222 
 223 
 224     /**
 225      * Start search beginning from the start of the given instruction list.
 226      *
 227      * @param pattern
 228      *          the instruction pattern to search for, where case is ignored
 229      * @return iterator of matches where e.nextElement() returns an array of
 230      *         instruction handles describing the matched area
 231      */
 232     public final Iterator<InstructionHandle[]> search( final String pattern ) {
 233         return search(pattern, il.getStart(), null);
 234     }
 235 
 236 
 237     /**
 238      * Start search beginning from `from'.
 239      *
 240      * @param pattern
 241      *          the instruction pattern to search for, where case is ignored
 242      * @param from
 243      *          where to start the search in the instruction list
 244      * @return iterator of matches where e.nextElement() returns an array of
 245      *         instruction handles describing the matched area
 246      */
 247     public final Iterator<InstructionHandle[]> search( final String pattern,
 248             final InstructionHandle from ) {
 249         return search(pattern, from, null);
 250     }
 251 
 252 
 253     /**
 254      * Start search beginning from the start of the given instruction list. Check
 255      * found matches with the constraint object.
 256      *
 257      * @param pattern
 258      *          the instruction pattern to search for, case is ignored
 259      * @param constraint
 260      *          constraints to be checked on matching code
 261      * @return instruction handle or `null' if the match failed
 262      */
 263     public final Iterator<InstructionHandle[]> search( final String pattern,
 264             final CodeConstraint constraint ) {
 265         return search(pattern, il.getStart(), constraint);
 266     }
 267 
 268 
 269     /**
 270      * Convert opcode number to char.
 271      */
 272     private static char makeChar( final short opcode ) {
 273         return (char) (opcode + OFFSET);
 274     }
 275 
 276 
 277     /**
 278      * @return the inquired instruction list
 279      */
 280     public final InstructionList getInstructionList() {
 281         return il;
 282     }
 283 
 284     /**
 285      * Code patterns found may be checked using an additional user-defined
 286      * constraint object whether they really match the needed criterion. I.e.,
 287      * check constraints that can not expressed with regular expressions.
 288      *
 289      */
 290     public interface CodeConstraint {
 291 
 292         /**
 293          * @param match
 294          *          array of instructions matching the requested pattern
 295          * @return true if the matched area is really useful
 296          */
 297         boolean checkCode( InstructionHandle[] match );
 298     }
 299 
 300     // Initialize pattern map

 301     static {
 302         map.put("arithmeticinstruction","(irem|lrem|iand|ior|ineg|isub|lneg|fneg|fmul|ldiv|fadd|lxor|frem|idiv|land|ixor|ishr|fsub|lshl|fdiv|iadd|lor|dmul|lsub|ishl|imul|lmul|lushr|dneg|iushr|lshr|ddiv|drem|dadd|ladd|dsub)");
 303         map.put("invokeinstruction", "(invokevirtual|invokeinterface|invokestatic|invokespecial|invokedynamic)");
 304         map.put("arrayinstruction", "(baload|aastore|saload|caload|fastore|lastore|iaload|castore|iastore|aaload|bastore|sastore|faload|laload|daload|dastore)");
 305         map.put("gotoinstruction", "(goto|goto_w)");
 306         map.put("conversioninstruction", "(d2l|l2d|i2s|d2i|l2i|i2b|l2f|d2f|f2i|i2d|i2l|f2d|i2c|f2l|i2f)");
 307         map.put("localvariableinstruction","(fstore|iinc|lload|dstore|dload|iload|aload|astore|istore|fload|lstore)");
 308         map.put("loadinstruction", "(fload|dload|lload|iload|aload)");
 309         map.put("fieldinstruction", "(getfield|putstatic|getstatic|putfield)");
 310         map.put("cpinstruction", "(ldc2_w|invokeinterface|invokedynamic|multianewarray|putstatic|instanceof|getstatic|checkcast|getfield|invokespecial|ldc_w|invokestatic|invokevirtual|putfield|ldc|new|anewarray)");
 311         map.put("stackinstruction", "(dup2|swap|dup2_x2|pop|pop2|dup|dup2_x1|dup_x2|dup_x1)");
 312         map.put("branchinstruction", "(ifle|if_acmpne|if_icmpeq|if_acmpeq|ifnonnull|goto_w|iflt|ifnull|if_icmpne|tableswitch|if_icmple|ifeq|if_icmplt|jsr_w|if_icmpgt|ifgt|jsr|goto|ifne|ifge|lookupswitch|if_icmpge)");
 313         map.put("returninstruction", "(lreturn|ireturn|freturn|dreturn|areturn|return)");
 314         map.put("storeinstruction", "(istore|fstore|dstore|astore|lstore)");
 315         map.put("select", "(tableswitch|lookupswitch)");
 316         map.put("ifinstruction", "(ifeq|ifgt|if_icmpne|if_icmpeq|ifge|ifnull|ifne|if_icmple|if_icmpge|if_acmpeq|if_icmplt|if_acmpne|ifnonnull|iflt|if_icmpgt|ifle)");
 317         map.put("jsrinstruction", "(jsr|jsr_w)");
 318         map.put("variablelengthinstruction", "(tableswitch|jsr|goto|lookupswitch)");
 319         map.put("unconditionalbranch", "(goto|jsr|jsr_w|athrow|goto_w)");
 320         map.put("constantpushinstruction", "(dconst|bipush|sipush|fconst|iconst|lconst)");
 321         map.put("typedinstruction", "(imul|lsub|aload|fload|lor|new|aaload|fcmpg|iand|iaload|lrem|idiv|d2l|isub|dcmpg|dastore|ret|f2d|f2i|drem|iinc|i2c|checkcast|frem|lreturn|astore|lushr|daload|dneg|fastore|istore|lshl|ldiv|lstore|areturn|ishr|ldc_w|invokeinterface|invokedynamic|aastore|lxor|ishl|l2d|i2f|return|faload|sipush|iushr|caload|instanceof|invokespecial|putfield|fmul|ireturn|laload|d2f|lneg|ixor|i2l|fdiv|lastore|multianewarray|i2b|getstatic|i2d|putstatic|fcmpl|saload|ladd|irem|dload|jsr_w|dconst|dcmpl|fsub|freturn|ldc|aconst_null|castore|lmul|ldc2_w|dadd|iconst|f2l|ddiv|dstore|land|jsr|anewarray|dmul|bipush|dsub|sastore|d2i|i2s|lshr|iadd|l2i|lload|bastore|fstore|fneg|iload|fadd|baload|fconst|ior|ineg|dreturn|l2f|lconst|getfield|invokevirtual|invokestatic|iastore)");
 322         map.put("popinstruction", "(fstore|dstore|pop|pop2|astore|putstatic|istore|lstore)");
 323         map.put("allocationinstruction", "(multianewarray|new|anewarray|newarray)");
 324         map.put("indexedinstruction", "(lload|lstore|fload|ldc2_w|invokeinterface|invokedynamic|multianewarray|astore|dload|putstatic|instanceof|getstatic|checkcast|getfield|invokespecial|dstore|istore|iinc|ldc_w|ret|fstore|invokestatic|iload|putfield|invokevirtual|ldc|new|aload|anewarray)");
 325         map.put("pushinstruction", "(dup|lload|dup2|bipush|fload|ldc2_w|sipush|lconst|fconst|dload|getstatic|ldc_w|aconst_null|dconst|iload|ldc|iconst|aload)");
 326         map.put("stackproducer", "(imul|lsub|aload|fload|lor|new|aaload|fcmpg|iand|iaload|lrem|idiv|d2l|isub|dcmpg|dup|f2d|f2i|drem|i2c|checkcast|frem|lushr|daload|dneg|lshl|ldiv|ishr|ldc_w|invokeinterface|invokedynamic|lxor|ishl|l2d|i2f|faload|sipush|iushr|caload|instanceof|invokespecial|fmul|laload|d2f|lneg|ixor|i2l|fdiv|getstatic|i2b|swap|i2d|dup2|fcmpl|saload|ladd|irem|dload|jsr_w|dconst|dcmpl|fsub|ldc|arraylength|aconst_null|tableswitch|lmul|ldc2_w|iconst|dadd|f2l|ddiv|land|jsr|anewarray|dmul|bipush|dsub|d2i|newarray|i2s|lshr|iadd|lload|l2i|fneg|iload|fadd|baload|fconst|lookupswitch|ior|ineg|lconst|l2f|getfield|invokevirtual|invokestatic)");
 327         map.put("stackconsumer", "(imul|lsub|lor|iflt|fcmpg|if_icmpgt|iand|ifeq|if_icmplt|lrem|ifnonnull|idiv|d2l|isub|dcmpg|dastore|if_icmpeq|f2d|f2i|drem|i2c|checkcast|frem|lreturn|astore|lushr|pop2|monitorexit|dneg|fastore|istore|lshl|ldiv|lstore|areturn|if_icmpge|ishr|monitorenter|invokeinterface|invokedynamic|aastore|lxor|ishl|l2d|i2f|return|iushr|instanceof|invokespecial|fmul|ireturn|d2f|lneg|ixor|pop|i2l|ifnull|fdiv|lastore|i2b|if_acmpeq|ifge|swap|i2d|putstatic|fcmpl|ladd|irem|dcmpl|fsub|freturn|ifgt|castore|lmul|dadd|f2l|ddiv|dstore|land|if_icmpne|if_acmpne|dmul|dsub|sastore|ifle|d2i|i2s|lshr|iadd|l2i|bastore|fstore|fneg|fadd|ior|ineg|ifne|dreturn|l2f|if_icmple|getfield|invokevirtual|invokestatic|iastore)");
 328         map.put("exceptionthrower","(irem|lrem|laload|putstatic|baload|dastore|areturn|getstatic|ldiv|anewarray|iastore|castore|idiv|saload|lastore|fastore|putfield|lreturn|caload|getfield|return|aastore|freturn|newarray|instanceof|multianewarray|athrow|faload|iaload|aaload|dreturn|monitorenter|checkcast|bastore|arraylength|new|invokevirtual|sastore|ldc_w|ireturn|invokespecial|monitorexit|invokeinterface|invokedynamic|ldc|invokestatic|daload)");
 329         map.put("loadclass", "(multianewarray|invokeinterface|invokedynamic|instanceof|invokespecial|putfield|checkcast|putstatic|invokevirtual|new|getstatic|invokestatic|getfield|anewarray)");
 330         map.put("instructiontargeter", "(ifle|if_acmpne|if_icmpeq|if_acmpeq|ifnonnull|goto_w|iflt|ifnull|if_icmpne|tableswitch|if_icmple|ifeq|if_icmplt|jsr_w|if_icmpgt|ifgt|jsr|goto|ifne|ifge|lookupswitch|if_icmpge)");

 331         // Some aliases
 332         map.put("if_icmp", "(if_icmpne|if_icmpeq|if_icmple|if_icmpge|if_icmplt|if_icmpgt)");
 333         map.put("if_acmp", "(if_acmpeq|if_acmpne)");
 334         map.put("if", "(ifeq|ifne|iflt|ifge|ifgt|ifle)");

 335         // Precompile some aliases first
 336         map.put("iconst", precompile(Const.ICONST_0, Const.ICONST_5, Const.ICONST_M1));
 337         map.put("lconst", new String(new char[] { '(', makeChar(Const.LCONST_0), '|', makeChar(Const.LCONST_1), ')' }));
 338         map.put("dconst", new String(new char[] { '(', makeChar(Const.DCONST_0), '|', makeChar(Const.DCONST_1), ')' }));
 339         map.put("fconst", new String(new char[] { '(', makeChar(Const.FCONST_0), '|', makeChar(Const.FCONST_1), '|', makeChar(Const.FCONST_2), ')' }));
 340         map.put("lload", precompile(Const.LLOAD_0, Const.LLOAD_3, Const.LLOAD));
 341         map.put("iload", precompile(Const.ILOAD_0, Const.ILOAD_3, Const.ILOAD));
 342         map.put("dload", precompile(Const.DLOAD_0, Const.DLOAD_3, Const.DLOAD));
 343         map.put("fload", precompile(Const.FLOAD_0, Const.FLOAD_3, Const.FLOAD));
 344         map.put("aload", precompile(Const.ALOAD_0, Const.ALOAD_3, Const.ALOAD));
 345         map.put("lstore", precompile(Const.LSTORE_0, Const.LSTORE_3, Const.LSTORE));
 346         map.put("istore", precompile(Const.ISTORE_0, Const.ISTORE_3, Const.ISTORE));
 347         map.put("dstore", precompile(Const.DSTORE_0, Const.DSTORE_3, Const.DSTORE));
 348         map.put("fstore", precompile(Const.FSTORE_0, Const.FSTORE_3, Const.FSTORE));
 349         map.put("astore", precompile(Const.ASTORE_0, Const.ASTORE_3, Const.ASTORE));




 350         // Compile strings
 351         for (final Map.Entry<String, String> entry : map.entrySet()) {
 352             final String key = entry.getKey();
 353             final String value = entry.getValue();
 354             final char ch = value.charAt(1); // Omit already precompiled patterns
 355             if (ch < OFFSET) {


 356                 map.put(key, compilePattern(value)); // precompile all patterns
 357             }
 358         }

 359         // Add instruction alias to match anything
 360         final StringBuilder buf = new StringBuilder("(");
 361         for (short i = 0; i < NO_OPCODES; i++) {
 362             if (Const.getNoOfOperands(i) != Const.UNDEFINED) { // Not an invalid opcode


 363                 buf.append(makeChar(i));
 364                 if (i < NO_OPCODES - 1) {

 365                     buf.append('|');
 366                 }
 367             }
 368         }
 369         buf.append(')');

 370         map.put("instruction", buf.toString());
 371     }
 372 


 373 
 374     private static String precompile( final short from, final short to, final short extra ) {
 375         final StringBuilder buf = new StringBuilder("(");
 376         for (short i = from; i <= to; i++) {
 377             buf.append(makeChar(i));
 378             buf.append('|');
 379         }

 380         buf.append(makeChar(extra));
 381         buf.append(")");
 382         return buf.toString();
 383     }
 384 
 385 
 386     /*
 387      * Internal debugging routines.
 388      */
 389 //    private static final String pattern2string( String pattern ) {
 390 //        return pattern2string(pattern, true);
 391 //    }
 392 
 393 
 394 //    private static final String pattern2string( String pattern, boolean make_string ) {
 395 //        StringBuffer buf = new StringBuffer();
 396 //        for (int i = 0; i < pattern.length(); i++) {
 397 //            char ch = pattern.charAt(i);
 398 //            if (ch >= OFFSET) {
 399 //                if (make_string) {
 400 //                    buf.append(Constants.getOpcodeName(ch - OFFSET));
 401 //                } else {
 402 //                    buf.append((ch - OFFSET));
 403 //                }
 404 //            } else {
 405 //                buf.append(ch);
 406 //            }
 407 //        }
 408 //        return buf.toString();
 409 //    }
 410 }





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