Package com.tonic.analysis.verifier.type

Class TypeConstraint

  • public class TypeConstraint
extends Object
    Assignability and category rules over verification types.

    • Constructor Detail

      • TypeConstraint

        public TypeConstraint​(ClassPool classPool)
        Creates a constraint checker.
        Parameters:
        classPool - the pool used to walk superclass chains, or null to assume every reference relation holds

    • Method Detail

      • isAssignableTo

        public boolean isAssignableTo​(VerificationType source,
                              VerificationType target)
        Decides whether a value of one type may be stored where another is expected.
        Parameters:
        source - the type being supplied
        target - the type being expected
        Returns:
        true if the assignment is allowed, false if either type is null

      • isArrayLoadValid

        public boolean isArrayLoadValid​(VerificationType arrayType,
                                VerificationType expectedElement)
        Checks an array load: the operand must be a reference, and when its element type is known it must satisfy what the load opcode expects. An operand whose element type cannot be read is accepted, so an unresolvable type never fails verification.
        Parameters:
        arrayType - the type of the array operand
        expectedElement - the element type the load opcode expects, or null to check only the operand
        Returns:
        true if the load is allowed

      • isReceiverValid

        public boolean isReceiverValid​(VerificationType receiver,
                               String expectedOwner)
        Checks an invocation receiver, accepting null and uninitialized references. A receiver of known class is required to be the owner or a subclass of it; an interface owner is not constrained, matching the verifier's own treatment of interface calls, and an unresolvable owner is accepted.
        Parameters:
        receiver - the type on the stack in receiver position
        expectedOwner - internal name of the class declaring the callee, or null to check only the receiver
        Returns:
        true if the receiver is allowed

      • isThrowable

        public boolean isThrowable​(VerificationType type)
        Decides whether a value may be thrown, walking to Throwable when a class pool is available and accepting the type otherwise.
        Parameters:
        type - the type on the stack
        Returns:
        true if the value may be thrown

      • isInteger

        public boolean isInteger​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type is int

      • isLong

        public boolean isLong​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type is long

      • isFloat

        public boolean isFloat​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type is float

      • isDouble

        public boolean isDouble​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type is double

      • isCategory1

        public boolean isCategory1​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type takes one stack slot

      • isCategory2

        public boolean isCategory2​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type takes two stack slots

      • isReferenceType

        public boolean isReferenceType​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true if the type is a reference, including null and uninitialized ones

      • isPrimitiveType

        public boolean isPrimitiveType​(VerificationType type)
        Parameters:
        type - the type to test
        Returns:
        true for int, long, float, double or top