scala.tools.asm.tree.analysis.Interpreter Maven / Gradle / Ivy
// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
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package scala.tools.asm.tree.analysis;
import java.util.List;
import scala.tools.asm.Opcodes;
import scala.tools.asm.Type;
import scala.tools.asm.tree.AbstractInsnNode;
import scala.tools.asm.tree.TryCatchBlockNode;
/**
* A semantic bytecode interpreter. More precisely, this interpreter only manages the computation of
* values from other values: it does not manage the transfer of values to or from the stack, and to
* or from the local variables. This separation allows a generic bytecode {@link Analyzer} to work
* with various semantic interpreters, without needing to duplicate the code to simulate the
* transfer of values.
*
* @param type of the Value used for the analysis.
* @author Eric Bruneton
*/
public abstract class Interpreter {
/**
* The ASM API version supported by this interpreter. The value of this field must be one of the
* {@code ASM}x values in {@link Opcodes}.
*/
protected final int api;
/**
* Constructs a new {@link Interpreter}.
*
* @param api the ASM API version supported by this interpreter. Must be one of the {@code
* ASM}x values in {@link Opcodes}.
*/
protected Interpreter(final int api) {
this.api = api;
}
/**
* Creates a new value that represents the given type.
*
* Called for method parameters (including this), exception handler variable and
* with null type for variables reserved by long and double types.
*
*
An interpreter may choose to implement one or more of {@link
* Interpreter#newReturnTypeValue(Type)}, {@link Interpreter#newParameterValue(boolean, int,
* Type)}, {@link Interpreter#newEmptyValue(int)}, {@link
* Interpreter#newExceptionValue(TryCatchBlockNode, Frame, Type)} to distinguish different types
* of new value.
*
* @param type a primitive or reference type, or {@literal null} to represent an uninitialized
* value.
* @return a value that represents the given type. The size of the returned value must be equal to
* the size of the given type.
*/
public abstract V newValue(Type type);
/**
* Creates a new value that represents the given parameter type. This method is called to
* initialize the value of a local corresponding to a method parameter in a frame.
*
*
By default, calls newValue(type).
*
* @param isInstanceMethod {@literal true} if the method is non-static.
* @param local the local variable index.
* @param type a primitive or reference type.
* @return a value that represents the given type. The size of the returned value must be equal to
* the size of the given type.
*/
public V newParameterValue(final boolean isInstanceMethod, final int local, final Type type) {
return newValue(type);
}
/**
* Creates a new value that represents the given return type. This method is called to initialize
* the return type value of a frame.
*
*
By default, calls newValue(type).
*
* @param type a primitive or reference type.
* @return a value that represents the given type. The size of the returned value must be equal to
* the size of the given type.
*/
public V newReturnTypeValue(final Type type) {
return newValue(type);
}
/**
* Creates a new uninitialized value for a local variable. This method is called to initialize the
* value of a local that does not correspond to a method parameter, and to reset one half of a
* size-2 value when the other half is assigned a size-1 value.
*
*
By default, calls newValue(null).
*
* @param local the local variable index.
* @return a value representing an uninitialized value. The size of the returned value must be
* equal to 1.
*/
public V newEmptyValue(final int local) {
return newValue(null);
}
/**
* Creates a new value that represents the given exception type. This method is called to
* initialize the exception value on the call stack at the entry of an exception handler.
*
*
By default, calls newValue(exceptionType).
*
* @param tryCatchBlockNode the exception handler.
* @param handlerFrame the exception handler frame.
* @param exceptionType the exception type handled by this handler.
* @return a value that represents the given {@code exceptionType}. The size of the returned value
* must be equal to 1.
*/
public V newExceptionValue(
final TryCatchBlockNode tryCatchBlockNode,
final Frame handlerFrame,
final Type exceptionType) {
return newValue(exceptionType);
}
/**
* Interprets a bytecode instruction without arguments. This method is called for the following
* opcodes:
*
* ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5,
* LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, BIPUSH, SIPUSH, LDC, JSR,
* GETSTATIC, NEW
*
* @param insn the bytecode instruction to be interpreted.
* @return the result of the interpretation of the given instruction.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract V newOperation(AbstractInsnNode insn) throws AnalyzerException;
/**
* Interprets a bytecode instruction that moves a value on the stack or to or from local
* variables. This method is called for the following opcodes:
*
*
ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE, DUP, DUP_X1,
* DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP
*
* @param insn the bytecode instruction to be interpreted.
* @param value the value that must be moved by the instruction.
* @return the result of the interpretation of the given instruction. The returned value must be
* {@code equal} to the given value.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract V copyOperation(AbstractInsnNode insn, V value) throws AnalyzerException;
/**
* Interprets a bytecode instruction with a single argument. This method is called for the
* following opcodes:
*
*
INEG, LNEG, FNEG, DNEG, IINC, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F,
* I2B, I2C, I2S, IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, TABLESWITCH, LOOKUPSWITCH, IRETURN, LRETURN,
* FRETURN, DRETURN, ARETURN, PUTSTATIC, GETFIELD, NEWARRAY, ANEWARRAY, ARRAYLENGTH, ATHROW,
* CHECKCAST, INSTANCEOF, MONITORENTER, MONITOREXIT, IFNULL, IFNONNULL
*
* @param insn the bytecode instruction to be interpreted.
* @param value the argument of the instruction to be interpreted.
* @return the result of the interpretation of the given instruction.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract V unaryOperation(AbstractInsnNode insn, V value) throws AnalyzerException;
/**
* Interprets a bytecode instruction with two arguments. This method is called for the following
* opcodes:
*
*
IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IADD, LADD, FADD, DADD,
* ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM,
* ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, LCMP, FCMPL, FCMPG,
* DCMPL, DCMPG, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ,
* IF_ACMPNE, PUTFIELD
*
* @param insn the bytecode instruction to be interpreted.
* @param value1 the first argument of the instruction to be interpreted.
* @param value2 the second argument of the instruction to be interpreted.
* @return the result of the interpretation of the given instruction.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract V binaryOperation(AbstractInsnNode insn, V value1, V value2)
throws AnalyzerException;
/**
* Interprets a bytecode instruction with three arguments. This method is called for the following
* opcodes:
*
*
IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE
*
* @param insn the bytecode instruction to be interpreted.
* @param value1 the first argument of the instruction to be interpreted.
* @param value2 the second argument of the instruction to be interpreted.
* @param value3 the third argument of the instruction to be interpreted.
* @return the result of the interpretation of the given instruction.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract V ternaryOperation(AbstractInsnNode insn, V value1, V value2, V value3)
throws AnalyzerException;
/**
* Interprets a bytecode instruction with a variable number of arguments. This method is called
* for the following opcodes:
*
*
INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC, INVOKEINTERFACE, MULTIANEWARRAY and
* INVOKEDYNAMIC
*
* @param insn the bytecode instruction to be interpreted.
* @param values the arguments of the instruction to be interpreted.
* @return the result of the interpretation of the given instruction.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract V naryOperation(AbstractInsnNode insn, List values)
throws AnalyzerException;
/**
* Interprets a bytecode return instruction. This method is called for the following opcodes:
*
*
IRETURN, LRETURN, FRETURN, DRETURN, ARETURN
*
* @param insn the bytecode instruction to be interpreted.
* @param value the argument of the instruction to be interpreted.
* @param expected the expected return type of the analyzed method.
* @throws AnalyzerException if an error occurred during the interpretation.
*/
public abstract void returnOperation(AbstractInsnNode insn, V value, V expected)
throws AnalyzerException;
/**
* Merges two values. The merge operation must return a value that represents both values (for
* instance, if the two values are two types, the merged value must be a common super type of the
* two types. If the two values are integer intervals, the merged value must be an interval that
* contains the previous ones. Likewise for other types of values).
*
* @param value1 a value.
* @param value2 another value.
* @return the merged value. If the merged value is equal to {@code value1}, this method
* must return {@code value1}.
*/
public abstract V merge(V value1, V value2);
}