Java tutorial
// ASM: a very small and fast Java bytecode manipulation framework // Copyright (c) 2000-2011 INRIA, France Telecom // All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions // are met: // 1. Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // 2. Redistributions in binary form must reproduce the above copyright // notice, this list of conditions and the following disclaimer in the // documentation and/or other materials provided with the distribution. // 3. Neither the name of the copyright holders nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF // THE POSSIBILITY OF SUCH DAMAGE. package org.objectweb.asm.tree.analysis; import java.util.HashSet; import java.util.List; import java.util.Set; import org.objectweb.asm.Opcodes; import org.objectweb.asm.Type; import org.objectweb.asm.tree.AbstractInsnNode; import org.objectweb.asm.tree.FieldInsnNode; import org.objectweb.asm.tree.InvokeDynamicInsnNode; import org.objectweb.asm.tree.LdcInsnNode; import org.objectweb.asm.tree.MethodInsnNode; /** * An {@link Interpreter} for {@link SourceValue} values. * * @author Eric Bruneton */ public class SourceInterpreter extends Interpreter<SourceValue> implements Opcodes { /** * Constructs a new {@link SourceInterpreter} for the latest ASM API version. <i>Subclasses must * not use this constructor</i>. Instead, they must use the {@link #SourceInterpreter(int)} * version. */ public SourceInterpreter() { super(/* latest api = */ ASM7); if (getClass() != SourceInterpreter.class) { throw new IllegalStateException(); } } /** * Constructs a new {@link SourceInterpreter}. * * @param api the ASM API version supported by this interpreter. Must be one of {@link * org.objectweb.asm.Opcodes#ASM4}, {@link org.objectweb.asm.Opcodes#ASM5}, {@link * org.objectweb.asm.Opcodes#ASM6} or {@link org.objectweb.asm.Opcodes#ASM7}. */ protected SourceInterpreter(final int api) { super(api); } @Override public SourceValue newValue(final Type type) { if (type == Type.VOID_TYPE) { return null; } return new SourceValue(type == null ? 1 : type.getSize()); } @Override public SourceValue newOperation(final AbstractInsnNode insn) { int size; switch (insn.getOpcode()) { case LCONST_0: case LCONST_1: case DCONST_0: case DCONST_1: size = 2; break; case LDC: Object value = ((LdcInsnNode) insn).cst; size = value instanceof Long || value instanceof Double ? 2 : 1; break; case GETSTATIC: size = Type.getType(((FieldInsnNode) insn).desc).getSize(); break; default: size = 1; break; } return new SourceValue(size, insn); } @Override public SourceValue copyOperation(final AbstractInsnNode insn, final SourceValue value) { return new SourceValue(value.getSize(), insn); } @Override public SourceValue unaryOperation(final AbstractInsnNode insn, final SourceValue value) { int size; switch (insn.getOpcode()) { case LNEG: case DNEG: case I2L: case I2D: case L2D: case F2L: case F2D: case D2L: size = 2; break; case GETFIELD: size = Type.getType(((FieldInsnNode) insn).desc).getSize(); break; default: size = 1; break; } return new SourceValue(size, insn); } @Override public SourceValue binaryOperation(final AbstractInsnNode insn, final SourceValue value1, final SourceValue value2) { int size; switch (insn.getOpcode()) { case LALOAD: case DALOAD: case LADD: case DADD: case LSUB: case DSUB: case LMUL: case DMUL: case LDIV: case DDIV: case LREM: case DREM: case LSHL: case LSHR: case LUSHR: case LAND: case LOR: case LXOR: size = 2; break; default: size = 1; break; } return new SourceValue(size, insn); } @Override public SourceValue ternaryOperation(final AbstractInsnNode insn, final SourceValue value1, final SourceValue value2, final SourceValue value3) { return new SourceValue(1, insn); } @Override public SourceValue naryOperation(final AbstractInsnNode insn, final List<? extends SourceValue> values) { int size; int opcode = insn.getOpcode(); if (opcode == MULTIANEWARRAY) { size = 1; } else if (opcode == INVOKEDYNAMIC) { size = Type.getReturnType(((InvokeDynamicInsnNode) insn).desc).getSize(); } else { size = Type.getReturnType(((MethodInsnNode) insn).desc).getSize(); } return new SourceValue(size, insn); } @Override public void returnOperation(final AbstractInsnNode insn, final SourceValue value, final SourceValue expected) { // Nothing to do. } @Override public SourceValue merge(final SourceValue value1, final SourceValue value2) { if (value1.insns instanceof SmallSet && value2.insns instanceof SmallSet) { Set<AbstractInsnNode> setUnion = ((SmallSet<AbstractInsnNode>) value1.insns) .union((SmallSet<AbstractInsnNode>) value2.insns); if (setUnion == value1.insns && value1.size == value2.size) { return value1; } else { return new SourceValue(Math.min(value1.size, value2.size), setUnion); } } if (value1.size != value2.size || !containsAll(value1.insns, value2.insns)) { HashSet<AbstractInsnNode> setUnion = new HashSet<>(); setUnion.addAll(value1.insns); setUnion.addAll(value2.insns); return new SourceValue(Math.min(value1.size, value2.size), setUnion); } return value1; } private static <E> boolean containsAll(final Set<E> self, final Set<E> other) { if (self.size() < other.size()) { return false; } return self.containsAll(other); } }