Package com.tonic.analysis.query.util

Class ArgumentTypeAnalyzer

java.lang.Object

com.tonic.analysis.query.util.ArgumentTypeAnalyzer

public class ArgumentTypeAnalyzer
extends Object

Static helpers for classifying invoke-instruction arguments by how they are produced.

Constructor Summary

Constructors

Constructor	Description
ArgumentTypeAnalyzer()

Method Summary

Modifier and Type	Method	Description
static ArgumentType	classifyInstruction(Instruction instr)	Buckets a producing instruction into the argument kind a query matches on.
static int	countDescriptorArguments(String desc)	Counts the parameters in a method descriptor, treating an array and its element as one parameter.
static Instruction	findArgumentProducer(CodeWriter codeWriter, int invokeIndex, int argIndex, int totalArgs, Instruction invokeInstr)	Walks backwards from an invoke, tracking stack depth, to find the instruction that pushed one of its arguments.
static int	getArgumentCount(Instruction invokeInstr)	Counts the declared arguments of an invoke, receiver excluded.
static String	getDescriptor(Instruction invokeInstr)	Reads the callee descriptor off an invoke; for invokedynamic the descriptor is cut out of the resolved call site signature.
static boolean	isInvokeInstruction(Instruction instr)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ArgumentTypeAnalyzer

public ArgumentTypeAnalyzer()

Method Detail

isInvokeInstruction

public static boolean isInvokeInstruction(Instruction instr)

Parameters:

instr - the instruction to test

Returns:

true for any of the five invoke opcodes

getArgumentCount

public static int getArgumentCount(Instruction invokeInstr)

Counts the declared arguments of an invoke, receiver excluded.

Parameters:

invokeInstr - the invoke instruction

Returns:

the argument count, 0 if the descriptor cannot be resolved

countDescriptorArguments

public static int countDescriptorArguments(String desc)

Counts the parameters in a method descriptor, treating an array and its element as one parameter.

Parameters:

desc - the method descriptor

Returns:

the parameter count, 0 if the descriptor is null or does not start with '('

findArgumentProducer

public static Instruction findArgumentProducer(CodeWriter codeWriter,
                                               int invokeIndex,
                                               int argIndex,
                                               int totalArgs,
                                               Instruction invokeInstr)

Walks backwards from an invoke, tracking stack depth, to find the instruction that pushed one of its arguments.

Parameters:

codeWriter - the body being scanned

invokeIndex - index of the invoke instruction

argIndex - the argument position to trace

totalArgs - the invoke's argument count

invokeInstr - the invoke instruction, used for slot widths

Returns:

the producing instruction, or null if none was reached

getDescriptor

public static String getDescriptor(Instruction invokeInstr)

Reads the callee descriptor off an invoke; for invokedynamic the descriptor is cut out of the resolved call site signature.

Parameters:

invokeInstr - the invoke instruction

Returns:

the method descriptor, or null if the instruction is not an invoke

classifyInstruction

public static ArgumentType classifyInstruction(Instruction instr)

Buckets a producing instruction into the argument kind a query matches on.

Parameters:

instr - the instruction that produced the value

Returns:

LITERAL, FIELD, LOCAL, CALL, DYNAMIC, or ANY when nothing matches