| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| package org.apache.bcel.util; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Locale; |
| import java.util.Map; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| |
| import org.apache.bcel.Const; |
| import org.apache.bcel.generic.ClassGenException; |
| import org.apache.bcel.generic.InstructionHandle; |
| import org.apache.bcel.generic.InstructionList; |
| |
| /** |
| * InstructionFinder is a tool to search for given instructions patterns, i.e., |
| * match sequences of instructions in an instruction list via regular |
| * expressions. This can be used, e.g., in order to implement a peep hole |
| * optimizer that looks for code patterns and replaces them with faster |
| * equivalents. |
| * |
| * <p> |
| * This class internally uses the java.util.regex |
| * package to search for regular expressions. |
| * |
| * A typical application would look like this: |
| * |
| * <pre> |
| * |
| * |
| * 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]); |
| * ... |
| * } |
| * |
| * |
| * </pre> |
| * |
| * @see org.apache.bcel.generic.Instruction |
| * @see InstructionList |
| */ |
| public class InstructionFinder { |
| |
| private static final int OFFSET = 32767; // char + OFFSET is outside of LATIN-1 |
| private static final int NO_OPCODES = 256; // Potential number, some are not used |
| private static final Map<String, String> map = new HashMap<>(); |
| private final InstructionList il; |
| private String ilString; // instruction list as string |
| private InstructionHandle[] handles; // map instruction |
| |
| |
| // list to array |
| /** |
| * @param il |
| * instruction list to search for given patterns |
| */ |
| public InstructionFinder(final InstructionList il) { |
| this.il = il; |
| reread(); |
| } |
| |
| |
| /** |
| * Reread the instruction list, e.g., after you've altered the list upon a |
| * match. |
| */ |
| public final void reread() { |
| final int size = il.getLength(); |
| final 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()); |
| } |
| ilString = new String(buf); |
| } |
| |
| |
| /** |
| * 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". |
| */ |
| private static String mapName( final String pattern ) { |
| final String result = map.get(pattern); |
| if (result != null) { |
| return result; |
| } |
| for (short i = 0; i < NO_OPCODES; i++) { |
| if (pattern.equals(Const.getOpcodeName(i))) { |
| return "" + makeChar(i); |
| } |
| } |
| throw new IllegalArgumentException("Instruction unknown: " + 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 |
| */ |
| private static String compilePattern( final String pattern ) { |
| //Bug: BCEL-77 - Instructions are assumed to be english, to avoid odd Locale issues |
| final String lower = pattern.toLowerCase(Locale.ENGLISH); |
| final StringBuilder buf = new StringBuilder(); |
| final int size = pattern.length(); |
| for (int i = 0; i < size; i++) { |
| char ch = lower.charAt(i); |
| if (Character.isLetterOrDigit(ch)) { |
| final StringBuilder name = new StringBuilder(); |
| while ((Character.isLetterOrDigit(ch) || ch == '_') && i < size) { |
| name.append(ch); |
| if (++i >= size) { |
| break; |
| } |
| ch = lower.charAt(i); |
| } |
| i--; |
| buf.append(mapName(name.toString())); |
| } else if (!Character.isWhitespace(ch)) { |
| buf.append(ch); |
| } |
| } |
| return buf.toString(); |
| } |
| |
| |
| /** |
| * @return the matched piece of code as an array of instruction (handles) |
| */ |
| private InstructionHandle[] getMatch( final int matched_from, final int match_length ) { |
| final InstructionHandle[] match = new InstructionHandle[match_length]; |
| System.arraycopy(handles, matched_from, match, 0, match_length); |
| return match; |
| } |
| |
| |
| /** |
| * 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. |
| * <P> |
| * Example pattern: |
| * |
| * <pre> |
| * search("BranchInstruction NOP ((IfInstruction|GOTO)+ ISTORE Instruction)*"); |
| * </pre> |
| * |
| * <p> |
| * 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 |
| */ |
| public final Iterator<InstructionHandle[]> search( final String pattern, final InstructionHandle from, final CodeConstraint constraint ) { |
| final 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."); |
| } |
| final Pattern regex = Pattern.compile(search); |
| final List<InstructionHandle[]> matches = new ArrayList<>(); |
| final Matcher matcher = regex.matcher(ilString); |
| while (start < ilString.length() && matcher.find(start)) { |
| final int startExpr = matcher.start(); |
| final int endExpr = matcher.end(); |
| final int lenExpr = endExpr - startExpr; |
| final InstructionHandle[] match = getMatch(startExpr, lenExpr); |
| if ((constraint == null) || constraint.checkCode(match)) { |
| matches.add(match); |
| } |
| start = endExpr; |
| } |
| return matches.iterator(); |
| } |
| |
| |
| /** |
| * 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 |
| */ |
| public final Iterator<InstructionHandle[]> search( final String pattern ) { |
| return search(pattern, il.getStart(), null); |
| } |
| |
| |
| /** |
| * 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 |
| */ |
| public final Iterator<InstructionHandle[]> search( final String pattern, final InstructionHandle from ) { |
| return search(pattern, from, null); |
| } |
| |
| |
| /** |
| * 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 |
| */ |
| public final Iterator<InstructionHandle[]> search( final String pattern, final CodeConstraint constraint ) { |
| return search(pattern, il.getStart(), constraint); |
| } |
| |
| |
| /** |
| * Convert opcode number to char. |
| */ |
| private static char makeChar( final short opcode ) { |
| return (char) (opcode + OFFSET); |
| } |
| |
| |
| /** |
| * @return the inquired instruction list |
| */ |
| public final InstructionList getInstructionList() { |
| return il; |
| } |
| |
| /** |
| * Code patterns found may be checked using an additional user-defined |
| * constraint object whether they really match the needed criterion. I.e., |
| * check constraints that can not expressed with regular expressions. |
| * |
| */ |
| public interface CodeConstraint { |
| |
| /** |
| * @param match |
| * array of instructions matching the requested pattern |
| * @return true if the matched area is really useful |
| */ |
| boolean checkCode( InstructionHandle[] match ); |
| } |
| |
| // Initialize pattern map |
| static { |
| 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|invokedynamic)"); |
| 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|invokedynamic|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|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)"); |
| 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|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)"); |
| 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|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)"); |
| 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)"); |
| 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)"); |
| map.put("loadclass", "(multianewarray|invokeinterface|invokedynamic|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(Const.ICONST_0, Const.ICONST_5, Const.ICONST_M1)); |
| map.put("lconst", new String(new char[] { '(', makeChar(Const.LCONST_0), '|', makeChar(Const.LCONST_1), ')' })); |
| map.put("dconst", new String(new char[] { '(', makeChar(Const.DCONST_0), '|', makeChar(Const.DCONST_1), ')' })); |
| map.put("fconst", new String(new char[] { '(', makeChar(Const.FCONST_0), '|', makeChar(Const.FCONST_1), '|', makeChar(Const.FCONST_2), ')' })); |
| map.put("lload", precompile(Const.LLOAD_0, Const.LLOAD_3, Const.LLOAD)); |
| map.put("iload", precompile(Const.ILOAD_0, Const.ILOAD_3, Const.ILOAD)); |
| map.put("dload", precompile(Const.DLOAD_0, Const.DLOAD_3, Const.DLOAD)); |
| map.put("fload", precompile(Const.FLOAD_0, Const.FLOAD_3, Const.FLOAD)); |
| map.put("aload", precompile(Const.ALOAD_0, Const.ALOAD_3, Const.ALOAD)); |
| map.put("lstore", precompile(Const.LSTORE_0, Const.LSTORE_3, Const.LSTORE)); |
| map.put("istore", precompile(Const.ISTORE_0, Const.ISTORE_3, Const.ISTORE)); |
| map.put("dstore", precompile(Const.DSTORE_0, Const.DSTORE_3, Const.DSTORE)); |
| map.put("fstore", precompile(Const.FSTORE_0, Const.FSTORE_3, Const.FSTORE)); |
| map.put("astore", precompile(Const.ASTORE_0, Const.ASTORE_3, Const.ASTORE)); |
| // Compile strings |
| for (final Map.Entry<String, String> entry : map.entrySet()) { |
| final String key = entry.getKey(); |
| final String value = entry.getValue(); |
| final 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 |
| final StringBuilder buf = new StringBuilder("("); |
| for (short i = 0; i < NO_OPCODES; i++) { |
| if (Const.getNoOfOperands(i) != Const.UNDEFINED) { // Not an invalid opcode |
| buf.append(makeChar(i)); |
| if (i < NO_OPCODES - 1) { |
| buf.append('|'); |
| } |
| } |
| } |
| buf.append(')'); |
| map.put("instruction", buf.toString()); |
| } |
| |
| |
| private static String precompile( final short from, final short to, final short extra ) { |
| final StringBuilder buf = new StringBuilder("("); |
| for (short i = from; i <= to; i++) { |
| buf.append(makeChar(i)); |
| buf.append('|'); |
| } |
| buf.append(makeChar(extra)); |
| buf.append(")"); |
| return buf.toString(); |
| } |
| |
| |
| /* |
| * Internal debugging routines. |
| */ |
| // private static final String pattern2string( String pattern ) { |
| // return pattern2string(pattern, true); |
| // } |
| |
| |
| // private static final String pattern2string( 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.getOpcodeName(ch - OFFSET)); |
| // } else { |
| // buf.append((ch - OFFSET)); |
| // } |
| // } else { |
| // buf.append(ch); |
| // } |
| // } |
| // return buf.toString(); |
| // } |
| } |