1/***
2 * ASM: a very small and fast Java bytecode manipulation framework
3 * Copyright (c) 2000-2007 INRIA, France Telecom
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the copyright holders nor the names of its
15 *    contributors may be used to endorse or promote products derived from
16 *    this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28 * THE POSSIBILITY OF SUCH DAMAGE.
29 */
30package org.mockito.asm.tree.analysis;
31
32import java.util.List;
33
34import org.mockito.asm.Type;
35import org.mockito.asm.tree.AbstractInsnNode;
36
37/**
38 * A semantic bytecode interpreter. More precisely, this interpreter only
39 * manages the computation of values from other values: it does not manage the
40 * transfer of values to or from the stack, and to or from the local variables.
41 * This separation allows a generic bytecode {@link Analyzer} to work with
42 * various semantic interpreters, without needing to duplicate the code to
43 * simulate the transfer of values.
44 *
45 * @author Eric Bruneton
46 */
47public interface Interpreter {
48
49    /**
50     * Creates a new value that represents the given type.
51     *
52     * Called for method parameters (including <code>this</code>),
53     * exception handler variable and with <code>null</code> type
54     * for variables reserved by long and double types.
55     *
56     * @param type a primitive or reference type, or <tt>null</tt> to
57     *        represent an uninitialized value.
58     * @return a value that represents the given type. The size of the returned
59     *         value must be equal to the size of the given type.
60     */
61    Value newValue(Type type);
62
63    /**
64     * Interprets a bytecode instruction without arguments. This method is
65     * called for the following opcodes:
66     *
67     * ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4,
68     * ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0,
69     * DCONST_1, BIPUSH, SIPUSH, LDC, JSR, GETSTATIC, NEW
70     *
71     * @param insn the bytecode instruction to be interpreted.
72     * @return the result of the interpretation of the given instruction.
73     * @throws AnalyzerException if an error occured during the interpretation.
74     */
75    Value newOperation(AbstractInsnNode insn) throws AnalyzerException;
76
77    /**
78     * Interprets a bytecode instruction that moves a value on the stack or to
79     * or from local variables. This method is called for the following opcodes:
80     *
81     * ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE,
82     * ASTORE, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP
83     *
84     * @param insn the bytecode instruction to be interpreted.
85     * @param value the value that must be moved by the instruction.
86     * @return the result of the interpretation of the given instruction. The
87     *         returned value must be <tt>equal</tt> to the given value.
88     * @throws AnalyzerException if an error occured during the interpretation.
89     */
90    Value copyOperation(AbstractInsnNode insn, Value value)
91            throws AnalyzerException;
92
93    /**
94     * Interprets a bytecode instruction with a single argument. This method is
95     * called for the following opcodes:
96     *
97     * INEG, LNEG, FNEG, DNEG, IINC, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L,
98     * F2D, D2I, D2L, D2F, I2B, I2C, I2S, IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE,
99     * TABLESWITCH, LOOKUPSWITCH, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN,
100     * PUTSTATIC, GETFIELD, NEWARRAY, ANEWARRAY, ARRAYLENGTH, ATHROW, CHECKCAST,
101     * INSTANCEOF, MONITORENTER, MONITOREXIT, IFNULL, IFNONNULL
102     *
103     * @param insn the bytecode instruction to be interpreted.
104     * @param value the argument of the instruction to be interpreted.
105     * @return the result of the interpretation of the given instruction.
106     * @throws AnalyzerException if an error occured during the interpretation.
107     */
108    Value unaryOperation(AbstractInsnNode insn, Value value)
109            throws AnalyzerException;
110
111    /**
112     * Interprets a bytecode instruction with two arguments. This method is
113     * called for the following opcodes:
114     *
115     * IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IADD,
116     * LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV,
117     * LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, ISHL, LSHL, ISHR, LSHR, IUSHR,
118     * LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, LCMP, FCMPL, FCMPG, DCMPL,
119     * DCMPG, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE,
120     * IF_ACMPEQ, IF_ACMPNE, PUTFIELD
121     *
122     * @param insn the bytecode instruction to be interpreted.
123     * @param value1 the first argument of the instruction to be interpreted.
124     * @param value2 the second argument of the instruction to be interpreted.
125     * @return the result of the interpretation of the given instruction.
126     * @throws AnalyzerException if an error occured during the interpretation.
127     */
128    Value binaryOperation(AbstractInsnNode insn, Value value1, Value value2)
129            throws AnalyzerException;
130
131    /**
132     * Interprets a bytecode instruction with three arguments. This method is
133     * called for the following opcodes:
134     *
135     * IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE
136     *
137     * @param insn the bytecode instruction to be interpreted.
138     * @param value1 the first argument of the instruction to be interpreted.
139     * @param value2 the second argument of the instruction to be interpreted.
140     * @param value3 the third argument of the instruction to be interpreted.
141     * @return the result of the interpretation of the given instruction.
142     * @throws AnalyzerException if an error occured during the interpretation.
143     */
144    Value ternaryOperation(
145        AbstractInsnNode insn,
146        Value value1,
147        Value value2,
148        Value value3) throws AnalyzerException;
149
150    /**
151     * Interprets a bytecode instruction with a variable number of arguments.
152     * This method is called for the following opcodes:
153     *
154     * INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC, INVOKEINTERFACE,
155     * MULTIANEWARRAY
156     *
157     * @param insn the bytecode instruction to be interpreted.
158     * @param values the arguments of the instruction to be interpreted.
159     * @return the result of the interpretation of the given instruction.
160     * @throws AnalyzerException if an error occured during the interpretation.
161     */
162    Value naryOperation(AbstractInsnNode insn, List values)
163            throws AnalyzerException;
164
165    /**
166     * Merges two values. The merge operation must return a value that
167     * represents both values (for instance, if the two values are two types,
168     * the merged value must be a common super type of the two types. If the two
169     * values are integer intervals, the merged value must be an interval that
170     * contains the previous ones. Likewise for other types of values).
171     *
172     * @param v a value.
173     * @param w another value.
174     * @return the merged value. If the merged value is equal to <tt>v</tt>,
175     *         this method <i>must</i> return <tt>v</tt>.
176     */
177    Value merge(Value v, Value w);
178}
179