Package org.objectweb.asm.tree.analysis
Class Interpreter<V extends Value>
- java.lang.Object
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- org.objectweb.asm.tree.analysis.Interpreter<V>
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- Type Parameters:
V
- type of the Value used for the analysis.
- Direct Known Subclasses:
BasicInterpreter
,SourceInterpreter
public abstract class Interpreter<V extends Value> extends Object
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 bytecodeAnalyzer
to work with various semantic interpreters, without needing to duplicate the code to simulate the transfer of values.- Author:
- Eric Bruneton
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Field Summary
Fields Modifier and Type Field Description protected int
api
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Constructor Summary
Constructors Modifier Constructor Description protected
Interpreter(int api)
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description abstract V
binaryOperation(AbstractInsnNode insn, V value1, V value2)
Interprets a bytecode instruction with two arguments.abstract V
copyOperation(AbstractInsnNode insn, V value)
Interprets a bytecode instruction that moves a value on the stack or to or from local variables.abstract V
merge(V v, V w)
Merges two values.abstract V
naryOperation(AbstractInsnNode insn, List<? extends V> values)
Interprets a bytecode instruction with a variable number of arguments.abstract V
newOperation(AbstractInsnNode insn)
Interprets a bytecode instruction without arguments.abstract V
newValue(Type type)
Creates a new value that represents the given type.abstract void
returnOperation(AbstractInsnNode insn, V value, V expected)
Interprets a bytecode return instruction.abstract V
ternaryOperation(AbstractInsnNode insn, V value1, V value2, V value3)
Interprets a bytecode instruction with three arguments.abstract V
unaryOperation(AbstractInsnNode insn, V value)
Interprets a bytecode instruction with a single argument.
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Method Detail
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newValue
public abstract V newValue(Type type)
Creates a new value that represents the given type. Called for method parameters (includingthis
), exception handler variable and withnull
type for variables reserved by long and double types.- Parameters:
type
- a primitive or reference type, or null to represent an uninitialized value.- Returns:
- a value that represents the given type. The size of the returned value must be equal to the size of the given type.
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newOperation
public abstract V newOperation(AbstractInsnNode insn) throws AnalyzerException
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- Parameters:
insn
- the bytecode instruction to be interpreted.- Returns:
- the result of the interpretation of the given instruction.
- Throws:
AnalyzerException
- if an error occured during the interpretation.
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copyOperation
public abstract V copyOperation(AbstractInsnNode insn, V value) 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- Parameters:
insn
- the bytecode instruction to be interpreted.value
- the value that must be moved by the instruction.- Returns:
- the result of the interpretation of the given instruction. The returned value must be equal to the given value.
- Throws:
AnalyzerException
- if an error occured during the interpretation.
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unaryOperation
public abstract V unaryOperation(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- Parameters:
insn
- the bytecode instruction to be interpreted.value
- the argument of the instruction to be interpreted.- Returns:
- the result of the interpretation of the given instruction.
- Throws:
AnalyzerException
- if an error occured during the interpretation.
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binaryOperation
public abstract V binaryOperation(AbstractInsnNode insn, V value1, V value2) 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- Parameters:
insn
- the bytecode instruction to be interpreted.value1
- the first argument of the instruction to be interpreted.value2
- the second argument of the instruction to be interpreted.- Returns:
- the result of the interpretation of the given instruction.
- Throws:
AnalyzerException
- if an error occured during the interpretation.
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ternaryOperation
public abstract V ternaryOperation(AbstractInsnNode insn, V value1, V value2, V value3) 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- Parameters:
insn
- the bytecode instruction to be interpreted.value1
- the first argument of the instruction to be interpreted.value2
- the second argument of the instruction to be interpreted.value3
- the third argument of the instruction to be interpreted.- Returns:
- the result of the interpretation of the given instruction.
- Throws:
AnalyzerException
- if an error occured during the interpretation.
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naryOperation
public abstract V naryOperation(AbstractInsnNode insn, List<? extends V> values) 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- Parameters:
insn
- the bytecode instruction to be interpreted.values
- the arguments of the instruction to be interpreted.- Returns:
- the result of the interpretation of the given instruction.
- Throws:
AnalyzerException
- if an error occured during the interpretation.
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returnOperation
public abstract void returnOperation(AbstractInsnNode insn, V value, V expected) throws AnalyzerException
Interprets a bytecode return instruction. This method is called for the following opcodes: IRETURN, LRETURN, FRETURN, DRETURN, ARETURN- Parameters:
insn
- the bytecode instruction to be interpreted.value
- the argument of the instruction to be interpreted.expected
- the expected return type of the analyzed method.- Throws:
AnalyzerException
- if an error occured during the interpretation.
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merge
public abstract V merge(V v, V w)
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).- Parameters:
v
- a value.w
- another value.- Returns:
- the merged value. If the merged value is equal to v, this method must return v.
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