File	Doc	Category	Size	Date	Package
InstructionFinder.java	API Doc	Java SE 5 API	20140	Fri Aug 26 14:55:24 BST 2005	com.sun.org.apache.bcel.internal.util

InstructionFinder

• java.lang.Object

InstructionFinder f = new InstructionFinder(il);
String pat = "IfInstruction ICONST_0 GOTO ICONST_1 NOP (IFEQ|IFNE)";

for(Iterator i = f.search(pat, constraint); i.hasNext(); ) {
InstructionHandle[] match = (InstructionHandle[])i.next();
...
il.delete(match[1], match[5]);
...
}

Fields Summary
private static final int	OFFSET
private static final int	NO_OPCODES
private static final HashMap	map
private InstructionList	il
private String	il_string
private InstructionHandle[]	handles

Constructors Summary
public InstructionFinder(InstructionList il) param il instruction list to search for given patterns // map instruction list to array this.il = il; reread();

Methods Summary
private static final java.lang.String	compilePattern(java.lang.String pattern) Replace symbolic names of instructions with the appropiate character and remove all white space from string. Meta characters such as +, * are ignored. param pattern The pattern to compile return translated regular expression string String lower = pattern.toLowerCase(); StringBuffer buf = new StringBuffer(); int size = pattern.length(); for(int i=0; i < size; i++) { char ch = lower.charAt(i); if(Character.isLetterOrDigit(ch)) { StringBuffer name = new StringBuffer(); while((Character.isLetterOrDigit(ch) || ch == '_") && i < size) { name.append(ch); if(++i < size) ch = lower.charAt(i); else break; } i--; buf.append(mapName(name.toString())); } else if(!Character.isWhitespace(ch)) buf.append(ch); } return buf.toString();
public final com.sun.org.apache.bcel.internal.generic.InstructionList	getInstructionList() return the inquired instruction list return il;
private com.sun.org.apache.bcel.internal.generic.InstructionHandle[]	getMatch(int matched_from, int match_length) return the matched piece of code as an array of instruction (handles) InstructionHandle[] match = new InstructionHandle[match_length]; System.arraycopy(handles, matched_from, match, 0, match_length); return match;
private static final char	makeChar(short opcode) Convert opcode number to char. return (char)(opcode + OFFSET);
private static final java.lang.String	mapName(java.lang.String pattern) Map symbolic instruction names like "getfield" to a single character. param pattern instruction pattern in lower case return encoded string for a pattern such as "BranchInstruction". String result = (String)map.get(pattern); if(result != null) return result; for(short i=0; i < NO_OPCODES; i++) if(pattern.equals(Constants.OPCODE_NAMES[i])) return "" + makeChar(i); throw new RuntimeException("Instruction unknown: " + pattern);
private static final java.lang.String	pattern2string(java.lang.String pattern) return pattern2string(pattern, true);
private static final java.lang.String	pattern2string(java.lang.String pattern, boolean make_string) StringBuffer buf = new StringBuffer(); for(int i=0; i < pattern.length(); i++) { char ch = pattern.charAt(i); if(ch >= OFFSET) { if(make_string) buf.append(Constants.OPCODE_NAMES[ch - OFFSET]); else buf.append((int)(ch - OFFSET)); } else buf.append(ch); } return buf.toString();
private static java.lang.String	precompile(short from, short to, short extra) 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)"); map.put("invokeinstruction", "(invokevirtual|invokeinterface|invokestatic|invokespecial)"); map.put("arrayinstruction", "(baload|aastore|saload|caload|fastore|lastore|iaload|castore|iastore|aaload|bastore|sastore|faload|laload|daload|dastore)"); map.put("gotoinstruction", "(goto|goto_w)"); map.put("conversioninstruction", "(d2l|l2d|i2s|d2i|l2i|i2b|l2f|d2f|f2i|i2d|i2l|f2d|i2c|f2l|i2f)"); map.put("localvariableinstruction", "(fstore|iinc|lload|dstore|dload|iload|aload|astore|istore|fload|lstore)"); map.put("loadinstruction", "(fload|dload|lload|iload|aload)"); map.put("fieldinstruction", "(getfield|putstatic|getstatic|putfield)"); map.put("cpinstruction", "(ldc2_w|invokeinterface|multianewarray|putstatic|instanceof|getstatic|checkcast|getfield|invokespecial|ldc_w|invokestatic|invokevirtual|putfield|ldc|new|anewarray)"); map.put("stackinstruction", "(dup2|swap|dup2_x2|pop|pop2|dup|dup2_x1|dup_x2|dup_x1)"); 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)"); map.put("returninstruction", "(lreturn|ireturn|freturn|dreturn|areturn|return)"); map.put("storeinstruction", "(istore|fstore|dstore|astore|lstore)"); map.put("select", "(tableswitch|lookupswitch)"); 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)"); map.put("jsrinstruction", "(jsr|jsr_w)"); map.put("variablelengthinstruction", "(tableswitch|jsr|goto|lookupswitch)"); map.put("unconditionalbranch", "(goto|jsr|jsr_w|athrow|goto_w)"); map.put("constantpushinstruction", "(dconst|bipush|sipush|fconst|iconst|lconst)"); 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)"); map.put("popinstruction", "(fstore|dstore|pop|pop2|astore|putstatic|istore|lstore)"); map.put("allocationinstruction", "(multianewarray|new|anewarray|newarray)"); 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)"); map.put("pushinstruction", "(dup|lload|dup2|bipush|fload|ldc2_w|sipush|lconst|fconst|dload|getstatic|ldc_w|aconst_null|dconst|iload|ldc|iconst|aload)"); 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)"); 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)"); 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)"); map.put("loadclass", "(multianewarray|invokeinterface|instanceof|invokespecial|putfield|checkcast|putstatic|invokevirtual|new|getstatic|invokestatic|getfield|anewarray)"); 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)"); // Some aliases map.put("if_icmp", "(if_icmpne|if_icmpeq|if_icmple|if_icmpge|if_icmplt|if_icmpgt)"); map.put("if_acmp", "(if_acmpeq|if_acmpne)"); map.put("if", "(ifeq|ifne|iflt|ifge|ifgt|ifle)"); // Precompile some aliases first map.put("iconst", precompile(Constants.ICONST_0, Constants.ICONST_5, Constants.ICONST_M1)); map.put("lconst", new String(new char[] { '(", makeChar(Constants.LCONST_0), '|", makeChar(Constants.LCONST_1), ')" })); map.put("dconst", new String(new char[] { '(", makeChar(Constants.DCONST_0), '|", makeChar(Constants.DCONST_1), ')" })); map.put("fconst", new String(new char[] { '(", makeChar(Constants.FCONST_0), '|", makeChar(Constants.FCONST_1), ')" })); map.put("iload", precompile(Constants.ILOAD_0, Constants.ILOAD_3, Constants.ILOAD)); map.put("dload", precompile(Constants.DLOAD_0, Constants.DLOAD_3, Constants.DLOAD)); map.put("fload", precompile(Constants.FLOAD_0, Constants.FLOAD_3, Constants.FLOAD)); map.put("aload", precompile(Constants.ALOAD_0, Constants.ALOAD_3, Constants.ALOAD)); map.put("istore", precompile(Constants.ISTORE_0, Constants.ISTORE_3, Constants.ISTORE)); map.put("dstore", precompile(Constants.DSTORE_0, Constants.DSTORE_3, Constants.DSTORE)); map.put("fstore", precompile(Constants.FSTORE_0, Constants.FSTORE_3, Constants.FSTORE)); map.put("astore", precompile(Constants.ASTORE_0, Constants.ASTORE_3, Constants.ASTORE)); // Compile strings for(Iterator i = map.keySet().iterator(); i.hasNext(); ) { String key = (String)i.next(); String value = (String)map.get(key); char ch = value.charAt(1); // Omit already precompiled patterns if(ch < OFFSET) { map.put(key, compilePattern(value)); // precompile all patterns } } // Add instruction alias to match anything StringBuffer buf = new StringBuffer("("); for(short i=0; i < NO_OPCODES; i++) { if(Constants.NO_OF_OPERANDS[i] != Constants.UNDEFINED) { // Not an invalid opcode buf.append(makeChar(i)); if(i < NO_OPCODES - 1) buf.append('|"); } } buf.append(')"); map.put("instruction", buf.toString()); StringBuffer buf = new StringBuffer("("); for(short i=from; i <= to; i++) { buf.append(makeChar(i)); buf.append('|"); } buf.append(makeChar(extra)); buf.append(")"); return buf.toString();
public final void	reread() Reread the instruction list, e.g., after you've altered the list upon a match. int size = il.getLength(); char[] buf = new char[size]; // Create a string with length equal to il length handles = il.getInstructionHandles(); // Map opcodes to characters for(int i=0; i < size; i++) buf[i] = makeChar(handles[i].getInstruction().getOpcode()); il_string = new String(buf);
public final java.util.Iterator	search(java.lang.String pattern, com.sun.org.apache.bcel.internal.generic.InstructionHandle from, com.sun.org.apache.bcel.internal.util.InstructionFinder$CodeConstraint constraint) Search for the given pattern in the instruction list. You can search for any valid opcode via its symbolic name, e.g. "istore". You can also use a super class or an interface name to match a whole set of instructions, e.g. "BranchInstruction" or "LoadInstruction". "istore" is also an alias for all "istore_x" instructions. Additional aliases are "if" for "ifxx", "if_icmp" for "if_icmpxx", "if_acmp" for "if_acmpxx". Consecutive instruction names must be separated by white space which will be removed during the compilation of the pattern. For the rest the usual pattern matching rules for regular expressions apply. Example pattern: search("BranchInstruction NOP ((IfInstruction|GOTO)+ ISTORE Instruction)*"); If you alter the instruction list upon a match such that other matching areas are affected, you should call reread() to update the finder and call search() again, because the matches are cached. param pattern the instruction pattern to search for, where case is ignored param from where to start the search in the instruction list param constraint optional CodeConstraint to check the found code pattern for user-defined constraints return iterator of matches where e.nextElement() returns an array of instruction handles describing the matched area String search = compilePattern(pattern); int start = -1; for(int i=0; i < handles.length; i++) { if(handles[i] == from) { start = i; // Where to start search from (index) break; } } if(start == -1) throw new ClassGenException("Instruction handle " + from + " not found in instruction list."); try { RE regex = new RE(search); ArrayList matches = new ArrayList(); while(start < il_string.length() && regex.match(il_string, start)) { int startExpr = regex.getParenStart(0); int endExpr = regex.getParenEnd(0); int lenExpr = regex.getParenLength(0); InstructionHandle[] match = getMatch(startExpr, lenExpr); if((constraint == null) || constraint.checkCode(match)) matches.add(match); start = endExpr; } return matches.iterator(); } catch(RESyntaxException e) { System.err.println(e); } return null;
public final java.util.Iterator	search(java.lang.String pattern) Start search beginning from the start of the given instruction list. param pattern the instruction pattern to search for, where case is ignored return iterator of matches where e.nextElement() returns an array of instruction handles describing the matched area return search(pattern, il.getStart(), null);
public final java.util.Iterator	search(java.lang.String pattern, com.sun.org.apache.bcel.internal.generic.InstructionHandle from) Start search beginning from `from'. param pattern the instruction pattern to search for, where case is ignored param from where to start the search in the instruction list return iterator of matches where e.nextElement() returns an array of instruction handles describing the matched area return search(pattern, from, null);
public final java.util.Iterator	search(java.lang.String pattern, com.sun.org.apache.bcel.internal.util.InstructionFinder$CodeConstraint constraint) Start search beginning from the start of the given instruction list. Check found matches with the constraint object. param pattern the instruction pattern to search for, case is ignored param constraint constraints to be checked on matching code return instruction handle or `null' if the match failed return search(pattern, il.getStart(), constraint);