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.
/***
 * 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.List;

import org.objectweb.asm.Handle;
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.IntInsnNode;
import org.objectweb.asm.tree.InvokeDynamicInsnNode;
import org.objectweb.asm.tree.LdcInsnNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MultiANewArrayInsnNode;
import org.objectweb.asm.tree.TypeInsnNode;

An Interpreter for BasicValue values. 
Author:
Eric Bruneton, Bing Ran/**
 * An {@link Interpreter} for {@link BasicValue} values.
 * 
 * @author Eric Bruneton
 * @author Bing Ran
 */
public class BasicInterpreter extends Interpreter<BasicValue> implements
        Opcodes {

    public BasicInterpreter() {
        super(ASM4);
    }

    protected BasicInterpreter(final int api) {
        super(api);
    }

    @Override
    public BasicValue newValue(final Type type) {
        if (type == null) {
            return BasicValue.UNINITIALIZED_VALUE;
        }
        switch (type.getSort()) {
        case Type.VOID:
            return null;
        case Type.BOOLEAN:
        case Type.CHAR:
        case Type.BYTE:
        case Type.SHORT:
        case Type.INT:
            return BasicValue.INT_VALUE;
        case Type.FLOAT:
            return BasicValue.FLOAT_VALUE;
        case Type.LONG:
            return BasicValue.LONG_VALUE;
        case Type.DOUBLE:
            return BasicValue.DOUBLE_VALUE;
        case Type.ARRAY:
        case Type.OBJECT:
            return BasicValue.REFERENCE_VALUE;
        default:
            throw new Error("Internal error");
        }
    }

    @Override
    public BasicValue newOperation(final AbstractInsnNode insn)
            throws AnalyzerException {
        switch (insn.getOpcode()) {
        case ACONST_NULL:
            return newValue(Type.getObjectType("null"));
        case ICONST_M1:
        case ICONST_0:
        case ICONST_1:
        case ICONST_2:
        case ICONST_3:
        case ICONST_4:
        case ICONST_5:
            return BasicValue.INT_VALUE;
        case LCONST_0:
        case LCONST_1:
            return BasicValue.LONG_VALUE;
        case FCONST_0:
        case FCONST_1:
        case FCONST_2:
            return BasicValue.FLOAT_VALUE;
        case DCONST_0:
        case DCONST_1:
            return BasicValue.DOUBLE_VALUE;
        case BIPUSH:
        case SIPUSH:
            return BasicValue.INT_VALUE;
        case LDC:
            Object cst = ((LdcInsnNode) insn).cst;
            if (cst instanceof Integer) {
                return BasicValue.INT_VALUE;
            } else if (cst instanceof Float) {
                return BasicValue.FLOAT_VALUE;
            } else if (cst instanceof Long) {
                return BasicValue.LONG_VALUE;
            } else if (cst instanceof Double) {
                return BasicValue.DOUBLE_VALUE;
            } else if (cst instanceof String) {
                return newValue(Type.getObjectType("java/lang/String"));
            } else if (cst instanceof Type) {
                int sort = ((Type) cst).getSort();
                if (sort == Type.OBJECT || sort == Type.ARRAY) {
                    return newValue(Type.getObjectType("java/lang/Class"));
                } else if (sort == Type.METHOD) {
                    return newValue(Type
                            .getObjectType("java/lang/invoke/MethodType"));
                } else {
                    throw new IllegalArgumentException("Illegal LDC constant "
                            + cst);
                }
            } else if (cst instanceof Handle) {
                return newValue(Type
                        .getObjectType("java/lang/invoke/MethodHandle"));
            } else {
                throw new IllegalArgumentException("Illegal LDC constant "
                        + cst);
            }
        case JSR:
            return BasicValue.RETURNADDRESS_VALUE;
        case GETSTATIC:
            return newValue(Type.getType(((FieldInsnNode) insn).desc));
        case NEW:
            return newValue(Type.getObjectType(((TypeInsnNode) insn).desc));
        default:
            throw new Error("Internal error.");
        }
    }

    @Override
    public BasicValue copyOperation(final AbstractInsnNode insn,
            final BasicValue value) throws AnalyzerException {
        return value;
    }

    @Override
    public BasicValue unaryOperation(final AbstractInsnNode insn,
            final BasicValue value) throws AnalyzerException {
        switch (insn.getOpcode()) {
        case INEG:
        case IINC:
        case L2I:
        case F2I:
        case D2I:
        case I2B:
        case I2C:
        case I2S:
            return BasicValue.INT_VALUE;
        case FNEG:
        case I2F:
        case L2F:
        case D2F:
            return BasicValue.FLOAT_VALUE;
        case LNEG:
        case I2L:
        case F2L:
        case D2L:
            return BasicValue.LONG_VALUE;
        case DNEG:
        case I2D:
        case L2D:
        case F2D:
            return BasicValue.DOUBLE_VALUE;
        case IFEQ:
        case IFNE:
        case IFLT:
        case IFGE:
        case IFGT:
        case IFLE:
        case TABLESWITCH:
        case LOOKUPSWITCH:
        case IRETURN:
        case LRETURN:
        case FRETURN:
        case DRETURN:
        case ARETURN:
        case PUTSTATIC:
            return null;
        case GETFIELD:
            return newValue(Type.getType(((FieldInsnNode) insn).desc));
        case NEWARRAY:
            switch (((IntInsnNode) insn).operand) {
            case T_BOOLEAN:
                return newValue(Type.getType("[Z"));
            case T_CHAR:
                return newValue(Type.getType("[C"));
            case T_BYTE:
                return newValue(Type.getType("[B"));
            case T_SHORT:
                return newValue(Type.getType("[S"));
            case T_INT:
                return newValue(Type.getType("[I"));
            case T_FLOAT:
                return newValue(Type.getType("[F"));
            case T_DOUBLE:
                return newValue(Type.getType("[D"));
            case T_LONG:
                return newValue(Type.getType("[J"));
            default:
                throw new AnalyzerException(insn, "Invalid array type");
            }
        case ANEWARRAY:
            String desc = ((TypeInsnNode) insn).desc;
            return newValue(Type.getType("[" + Type.getObjectType(desc)));
        case ARRAYLENGTH:
            return BasicValue.INT_VALUE;
        case ATHROW:
            return null;
        case CHECKCAST:
            desc = ((TypeInsnNode) insn).desc;
            return newValue(Type.getObjectType(desc));
        case INSTANCEOF:
            return BasicValue.INT_VALUE;
        case MONITORENTER:
        case MONITOREXIT:
        case IFNULL:
        case IFNONNULL:
            return null;
        default:
            throw new Error("Internal error.");
        }
    }

    @Override
    public BasicValue binaryOperation(final AbstractInsnNode insn,
            final BasicValue value1, final BasicValue value2)
            throws AnalyzerException {
        switch (insn.getOpcode()) {
        case IALOAD:
        case BALOAD:
        case CALOAD:
        case SALOAD:
        case IADD:
        case ISUB:
        case IMUL:
        case IDIV:
        case IREM:
        case ISHL:
        case ISHR:
        case IUSHR:
        case IAND:
        case IOR:
        case IXOR:
            return BasicValue.INT_VALUE;
        case FALOAD:
        case FADD:
        case FSUB:
        case FMUL:
        case FDIV:
        case FREM:
            return BasicValue.FLOAT_VALUE;
        case LALOAD:
        case LADD:
        case LSUB:
        case LMUL:
        case LDIV:
        case LREM:
        case LSHL:
        case LSHR:
        case LUSHR:
        case LAND:
        case LOR:
        case LXOR:
            return BasicValue.LONG_VALUE;
        case DALOAD:
        case DADD:
        case DSUB:
        case DMUL:
        case DDIV:
        case DREM:
            return BasicValue.DOUBLE_VALUE;
        case AALOAD:
            return BasicValue.REFERENCE_VALUE;
        case LCMP:
        case FCMPL:
        case FCMPG:
        case DCMPL:
        case DCMPG:
            return BasicValue.INT_VALUE;
        case IF_ICMPEQ:
        case IF_ICMPNE:
        case IF_ICMPLT:
        case IF_ICMPGE:
        case IF_ICMPGT:
        case IF_ICMPLE:
        case IF_ACMPEQ:
        case IF_ACMPNE:
        case PUTFIELD:
            return null;
        default:
            throw new Error("Internal error.");
        }
    }

    @Override
    public BasicValue ternaryOperation(final AbstractInsnNode insn,
            final BasicValue value1, final BasicValue value2,
            final BasicValue value3) throws AnalyzerException {
        return null;
    }

    @Override
    public BasicValue naryOperation(final AbstractInsnNode insn,
            final List<? extends BasicValue> values) throws AnalyzerException {
        int opcode = insn.getOpcode();
        if (opcode == MULTIANEWARRAY) {
            return newValue(Type.getType(((MultiANewArrayInsnNode) insn).desc));
        } else if (opcode == INVOKEDYNAMIC) {
            return newValue(Type
                    .getReturnType(((InvokeDynamicInsnNode) insn).desc));
        } else {
            return newValue(Type.getReturnType(((MethodInsnNode) insn).desc));
        }
    }

    @Override
    public void returnOperation(final AbstractInsnNode insn,
            final BasicValue value, final BasicValue expected)
            throws AnalyzerException {
    }

    @Override
    public BasicValue merge(final BasicValue v, final BasicValue w) {
        if (!v.equals(w)) {
            return BasicValue.UNINITIALIZED_VALUE;
        }
        return v;
    }
}