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package com.sun.org.apache.bcel.internal.util;

import com.sun.org.apache.bcel.internal.generic.*;
import com.sun.org.apache.bcel.internal.classfile.Utility;
import com.sun.org.apache.bcel.internal.Constants;
import java.io.PrintWriter;
import java.util.*;


Factory creates il.append() statements, and sets instruction targets. A helper class for BCELifier.
Author: M. Dahm
See Also:
  • BCELifier
/** * Factory creates il.append() statements, and sets instruction targets. * A helper class for BCELifier. * * @see BCELifier * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> */
class BCELFactory extends EmptyVisitor { private MethodGen _mg; private PrintWriter _out; private ConstantPoolGen _cp; BCELFactory(MethodGen mg, PrintWriter out) { _mg = mg; _cp = mg.getConstantPool(); _out = out; } private HashMap branch_map = new HashMap(); // Map<Instruction, InstructionHandle> public void start() { if(!_mg.isAbstract() && !_mg.isNative()) { for(InstructionHandle ih = _mg.getInstructionList().getStart(); ih != null; ih = ih.getNext()) { Instruction i = ih.getInstruction(); if(i instanceof BranchInstruction) { branch_map.put(i, ih); // memorize container } if(ih.hasTargeters()) { if(i instanceof BranchInstruction) { _out.println(" InstructionHandle ih_" + ih.getPosition() + ";"); } else { _out.print(" InstructionHandle ih_" + ih.getPosition() + " = "); } } else { _out.print(" "); } if(!visitInstruction(i)) i.accept(this); } updateBranchTargets(); updateExceptionHandlers(); } } private boolean visitInstruction(Instruction i) { short opcode = i.getOpcode(); if((InstructionConstants.INSTRUCTIONS[opcode] != null) && !(i instanceof ConstantPushInstruction) && !(i instanceof ReturnInstruction)) { // Handled below _out.println("il.append(InstructionConstants." + i.getName().toUpperCase() + ");"); return true; } return false; } public void visitLocalVariableInstruction(LocalVariableInstruction i) { short opcode = i.getOpcode(); Type type = i.getType(_cp); if(opcode == Constants.IINC) { _out.println("il.append(new IINC(" + i.getIndex() + ", " + ((IINC)i).getIncrement() + "));"); } else { String kind = (opcode < Constants.ISTORE)? "Load" : "Store"; _out.println("il.append(_factory.create" + kind + "(" + BCELifier.printType(type) + ", " + i.getIndex() + "));"); } } public void visitArrayInstruction(ArrayInstruction i) { short opcode = i.getOpcode(); Type type = i.getType(_cp); String kind = (opcode < Constants.IASTORE)? "Load" : "Store"; _out.println("il.append(_factory.createArray" + kind + "(" + BCELifier.printType(type) + "));"); } public void visitFieldInstruction(FieldInstruction i) { short opcode = i.getOpcode(); String class_name = i.getClassName(_cp); String field_name = i.getFieldName(_cp); Type type = i.getFieldType(_cp); _out.println("il.append(_factory.createFieldAccess(\"" + class_name + "\", \"" + field_name + "\", " + BCELifier.printType(type) + ", " + "Constants." + Constants.OPCODE_NAMES[opcode].toUpperCase() + "));"); } public void visitInvokeInstruction(InvokeInstruction i) { short opcode = i.getOpcode(); String class_name = i.getClassName(_cp); String method_name = i.getMethodName(_cp); Type type = i.getReturnType(_cp); Type[] arg_types = i.getArgumentTypes(_cp); _out.println("il.append(_factory.createInvoke(\"" + class_name + "\", \"" + method_name + "\", " + BCELifier.printType(type) + ", " + BCELifier.printArgumentTypes(arg_types) + ", " + "Constants." + Constants.OPCODE_NAMES[opcode].toUpperCase() + "));"); } public void visitAllocationInstruction(AllocationInstruction i) { Type type; if(i instanceof CPInstruction) { type = ((CPInstruction)i).getType(_cp); } else { type = ((NEWARRAY)i).getType(); } short opcode = ((Instruction)i).getOpcode(); int dim = 1; switch(opcode) { case Constants.NEW: _out.println("il.append(_factory.createNew(\"" + ((ObjectType)type).getClassName() + "\"));"); break; case Constants.MULTIANEWARRAY: dim = ((MULTIANEWARRAY)i).getDimensions(); case Constants.ANEWARRAY: case Constants.NEWARRAY: _out.println("il.append(_factory.createNewArray(" + BCELifier.printType(type) + ", (short) " + dim + "));"); break; default: throw new RuntimeException("Oops: " + opcode); } } private void createConstant(Object value) { String embed = value.toString(); if(value instanceof String) embed = '"' + Utility.convertString(value.toString()) + '"'; else if(value instanceof Character) embed = "(char)0x" + Integer.toHexString(((Character)value).charValue()); _out.println("il.append(new PUSH(_cp, " + embed + "));"); } public void visitLDC(LDC i) { createConstant(i.getValue(_cp)); } public void visitLDC2_W(LDC2_W i) { createConstant(i.getValue(_cp)); } public void visitConstantPushInstruction(ConstantPushInstruction i) { createConstant(i.getValue()); } public void visitINSTANCEOF(INSTANCEOF i) { Type type = i.getType(_cp); _out.println("il.append(new INSTANCEOF(_cp.addClass(" + BCELifier.printType(type) + ")));"); } public void visitCHECKCAST(CHECKCAST i) { Type type = i.getType(_cp); _out.println("il.append(_factory.createCheckCast(" + BCELifier.printType(type) + "));"); } public void visitReturnInstruction(ReturnInstruction i) { Type type = i.getType(_cp); _out.println("il.append(_factory.createReturn(" + BCELifier.printType(type) + "));"); } // Memorize BranchInstructions that need an update private ArrayList branches = new ArrayList(); public void visitBranchInstruction(BranchInstruction bi) { BranchHandle bh = (BranchHandle)branch_map.get(bi); int pos = bh.getPosition(); String name = bi.getName() + "_" + pos; if(bi instanceof Select) { Select s = (Select)bi; branches.add(bi); StringBuffer args = new StringBuffer("new int[] { "); int[] matchs = s.getMatchs(); for(int i=0; i < matchs.length; i++) { args.append(matchs[i]); if(i < matchs.length - 1) args.append(", "); } args.append(" }"); _out.print(" Select " + name + " = new " + bi.getName().toUpperCase() + "(" + args + ", new InstructionHandle[] { "); for(int i=0; i < matchs.length; i++) { _out.print("null"); if(i < matchs.length - 1) _out.print(", "); } _out.println(");"); } else { int t_pos = bh.getTarget().getPosition(); String target; if(pos > t_pos) { target = "ih_" + t_pos; } else { branches.add(bi); target = "null"; } _out.println(" BranchInstruction " + name + " = _factory.createBranchInstruction(" + "Constants." + bi.getName().toUpperCase() + ", " + target + ");"); } if(bh.hasTargeters()) _out.println(" ih_" + pos + " = il.append(" + name + ");"); else _out.println(" il.append(" + name + ");"); } public void visitRET(RET i) { _out.println("il.append(new RET(" + i.getIndex() + ")));"); } private void updateBranchTargets() { for(Iterator i = branches.iterator(); i.hasNext(); ) { BranchInstruction bi = (BranchInstruction)i.next(); BranchHandle bh = (BranchHandle)branch_map.get(bi); int pos = bh.getPosition(); String name = bi.getName() + "_" + pos; int t_pos = bh.getTarget().getPosition(); _out.println(" " + name + ".setTarget(ih_" + t_pos + ");"); if(bi instanceof Select) { InstructionHandle[] ihs = ((Select)bi).getTargets(); for(int j = 0; j < ihs.length; j++) { t_pos = ihs[j].getPosition(); _out.println(" " + name + ".setTarget(" + j + ", ih_" + t_pos + ");"); } } } } private void updateExceptionHandlers() { CodeExceptionGen[] handlers = _mg.getExceptionHandlers(); for(int i=0; i < handlers.length; i++) { CodeExceptionGen h = handlers[i]; String type = (h.getCatchType() == null)? "null" : BCELifier.printType(h.getCatchType()); _out.println(" method.addExceptionHandler(" + "ih_" + h.getStartPC().getPosition() + ", " + "ih_" + h.getEndPC().getPosition() + ", " + "ih_" + h.getHandlerPC().getPosition() + ", " + type + ");"); } } }