/*
 * Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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.
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package com.sun.org.apache.bcel.internal.util;

import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import com.sun.org.apache.bcel.internal.Const;
import com.sun.org.apache.bcel.internal.classfile.Utility;
import com.sun.org.apache.bcel.internal.generic.AllocationInstruction;
import com.sun.org.apache.bcel.internal.generic.ArrayInstruction;
import com.sun.org.apache.bcel.internal.generic.ArrayType;
import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.BranchInstruction;
import com.sun.org.apache.bcel.internal.generic.CHECKCAST;
import com.sun.org.apache.bcel.internal.generic.CPInstruction;
import com.sun.org.apache.bcel.internal.generic.CodeExceptionGen;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.ConstantPushInstruction;
import com.sun.org.apache.bcel.internal.generic.EmptyVisitor;
import com.sun.org.apache.bcel.internal.generic.FieldInstruction;
import com.sun.org.apache.bcel.internal.generic.IINC;
import com.sun.org.apache.bcel.internal.generic.INSTANCEOF;
import com.sun.org.apache.bcel.internal.generic.Instruction;
import com.sun.org.apache.bcel.internal.generic.InstructionConst;
import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
import com.sun.org.apache.bcel.internal.generic.InvokeInstruction;
import com.sun.org.apache.bcel.internal.generic.LDC;
import com.sun.org.apache.bcel.internal.generic.LDC2_W;
import com.sun.org.apache.bcel.internal.generic.LocalVariableInstruction;
import com.sun.org.apache.bcel.internal.generic.MULTIANEWARRAY;
import com.sun.org.apache.bcel.internal.generic.MethodGen;
import com.sun.org.apache.bcel.internal.generic.NEWARRAY;
import com.sun.org.apache.bcel.internal.generic.ObjectType;
import com.sun.org.apache.bcel.internal.generic.RET;
import com.sun.org.apache.bcel.internal.generic.ReturnInstruction;
import com.sun.org.apache.bcel.internal.generic.Select;
import com.sun.org.apache.bcel.internal.generic.Type;

Factory creates il.append() statements, and sets instruction targets. A helper class for BCELifier.
See Also:
  • BCELifier
@LastModified: Jan 2020
/** * Factory creates il.append() statements, and sets instruction targets. * A helper class for BCELifier. * * @see BCELifier * @LastModified: Jan 2020 */
class BCELFactory extends EmptyVisitor { private static final String CONSTANT_PREFIX = Const.class.getSimpleName()+"."; private final MethodGen _mg; private final PrintWriter _out; private final ConstantPoolGen _cp; BCELFactory(final MethodGen mg, final PrintWriter out) { _mg = mg; _cp = mg.getConstantPool(); _out = out; } private final Map<Instruction, InstructionHandle> branch_map = new HashMap<>(); public void start() { if (!_mg.isAbstract() && !_mg.isNative()) { for (InstructionHandle ih = _mg.getInstructionList().getStart(); ih != null; ih = ih .getNext()) { final 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( final Instruction i ) { final short opcode = i.getOpcode(); if ((InstructionConst.getInstruction(opcode) != null) && !(i instanceof ConstantPushInstruction) && !(i instanceof ReturnInstruction)) { // Handled below _out.println("il.append(InstructionConst." + i.getName().toUpperCase(Locale.ENGLISH) + ");"); return true; } return false; } @Override public void visitLocalVariableInstruction( final LocalVariableInstruction i ) { final short opcode = i.getOpcode(); final Type type = i.getType(_cp); if (opcode == Const.IINC) { _out.println("il.append(new IINC(" + i.getIndex() + ", " + ((IINC) i).getIncrement() + "));"); } else { final String kind = (opcode < Const.ISTORE) ? "Load" : "Store"; _out.println("il.append(_factory.create" + kind + "(" + BCELifier.printType(type) + ", " + i.getIndex() + "));"); } } @Override public void visitArrayInstruction( final ArrayInstruction i ) { final short opcode = i.getOpcode(); final Type type = i.getType(_cp); final String kind = (opcode < Const.IASTORE) ? "Load" : "Store"; _out.println("il.append(_factory.createArray" + kind + "(" + BCELifier.printType(type) + "));"); } @Override public void visitFieldInstruction( final FieldInstruction i ) { final short opcode = i.getOpcode(); final String class_name = i.getReferenceType(_cp).getSignature(); final String field_name = i.getFieldName(_cp); final Type type = i.getFieldType(_cp); _out.println("il.append(_factory.createFieldAccess(\"" + class_name + "\", \"" + field_name + "\", " + BCELifier.printType(type) + ", " + CONSTANT_PREFIX + Const.getOpcodeName(opcode).toUpperCase(Locale.ENGLISH) + "));"); } @Override public void visitInvokeInstruction( final InvokeInstruction i ) { final short opcode = i.getOpcode(); final String class_name = i.getReferenceType(_cp).getSignature(); final String method_name = i.getMethodName(_cp); final Type type = i.getReturnType(_cp); final Type[] arg_types = i.getArgumentTypes(_cp); _out.println("il.append(_factory.createInvoke(\"" + class_name + "\", \"" + method_name + "\", " + BCELifier.printType(type) + ", " + BCELifier.printArgumentTypes(arg_types) + ", " + CONSTANT_PREFIX + Const.getOpcodeName(opcode).toUpperCase(Locale.ENGLISH) + "));"); } @Override @SuppressWarnings("fallthrough") // by design for case Const.ANEWARRAY public void visitAllocationInstruction( final AllocationInstruction i ) { Type type; if (i instanceof CPInstruction) { type = ((CPInstruction) i).getType(_cp); } else { type = ((NEWARRAY) i).getType(); } final short opcode = ((Instruction) i).getOpcode(); int dim = 1; switch (opcode) { case Const.NEW: _out.println("il.append(_factory.createNew(\"" + ((ObjectType) type).getClassName() + "\"));"); break; case Const.MULTIANEWARRAY: dim = ((MULTIANEWARRAY) i).getDimensions(); //$FALL-THROUGH$ case Const.ANEWARRAY: case Const.NEWARRAY: if (type instanceof ArrayType) { type = ((ArrayType) type).getBasicType(); } _out.println("il.append(_factory.createNewArray(" + BCELifier.printType(type) + ", (short) " + dim + "));"); break; default: throw new RuntimeException("Oops: " + opcode); } } private void createConstant( final Object value ) { String embed = value.toString(); if (value instanceof String) { embed = '"' + Utility.convertString(embed) + '"'; } else if (value instanceof Character) { embed = "(char)0x" + Integer.toHexString(((Character) value).charValue()); } else if (value instanceof Float) { embed += "f"; } else if (value instanceof Long) { embed += "L"; } else if (value instanceof ObjectType) { final ObjectType ot = (ObjectType) value; embed = "new ObjectType(\""+ot.getClassName()+"\")"; } _out.println("il.append(new PUSH(_cp, " + embed + "));"); } @Override public void visitLDC( final LDC i ) { createConstant(i.getValue(_cp)); } @Override public void visitLDC2_W( final LDC2_W i ) { createConstant(i.getValue(_cp)); } @Override public void visitConstantPushInstruction( final ConstantPushInstruction i ) { createConstant(i.getValue()); } @Override public void visitINSTANCEOF( final INSTANCEOF i ) { final Type type = i.getType(_cp); _out.println("il.append(new INSTANCEOF(_cp.addClass(" + BCELifier.printType(type) + ")));"); } @Override public void visitCHECKCAST( final CHECKCAST i ) { final Type type = i.getType(_cp); _out.println("il.append(_factory.createCheckCast(" + BCELifier.printType(type) + "));"); } @Override public void visitReturnInstruction( final ReturnInstruction i ) { final Type type = i.getType(_cp); _out.println("il.append(_factory.createReturn(" + BCELifier.printType(type) + "));"); } // Memorize BranchInstructions that need an update private final List<BranchInstruction> branches = new ArrayList<>(); @Override public void visitBranchInstruction( final BranchInstruction bi ) { final BranchHandle bh = (BranchHandle) branch_map.get(bi); final int pos = bh.getPosition(); final String name = bi.getName() + "_" + pos; if (bi instanceof Select) { final Select s = (Select) bi; branches.add(bi); final StringBuilder args = new StringBuilder("new int[] { "); final 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(Locale.ENGLISH) + "(" + args + ", new InstructionHandle[] { "); for (int i = 0; i < matchs.length; i++) { _out.print("null"); if (i < matchs.length - 1) { _out.print(", "); } } _out.println(" }, null);"); } else { final 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(" + CONSTANT_PREFIX + bi.getName().toUpperCase(Locale.ENGLISH) + ", " + target + ");"); } if (bh.hasTargeters()) { _out.println(" ih_" + pos + " = il.append(" + name + ");"); } else { _out.println(" il.append(" + name + ");"); } } @Override public void visitRET( final RET i ) { _out.println("il.append(new RET(" + i.getIndex() + ")));"); } private void updateBranchTargets() { for (final BranchInstruction bi : branches) { final BranchHandle bh = (BranchHandle) branch_map.get(bi); final int pos = bh.getPosition(); final String name = bi.getName() + "_" + pos; int t_pos = bh.getTarget().getPosition(); _out.println(" " + name + ".setTarget(ih_" + t_pos + ");"); if (bi instanceof Select) { final 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() { final CodeExceptionGen[] handlers = _mg.getExceptionHandlers(); for (final CodeExceptionGen h : handlers) { final 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 + ");"); } } }