ValuesCoordinatingDomain
Related Doc:
package domain
Computation that returns the value stored in an array at a given index or an exception.
Computation that returns the value stored in an array at a given index or an
exception. The exceptions that may be thrown are: NullPointerException and
ArrayIndexOutOfBoundsException.
Computation that succeeds (updates the value stored in the array at the given index) or that throws an exception.
Computation that succeeds (updates the value stored in the array at the given
index) or that throws an exception. The exceptions that may be thrown are:
NullPointerException, ArrayIndexOutOfBoundsException and ArrayStoreException.
Abstracts over the concrete type of IllegalValue.
Abstracts over the concrete type of IllegalValue.
This type needs to be refined whenever the class IllegalValue
is refined or the type DomainValue is refined.
Abstracts over the concrete type of ReturnAddressValue.
Abstracts over the concrete type of ReturnAddressValue. Needs to be fixed
by some sub-trait/sub-class. In the simplest case (i.e., when neither the
Value trait nor the ReturnAddressValue trait was refined) it is sufficient
to write:
type DomainReturnAddressValue = ReturnAddressValue
Abstracts over the concrete type of Value.
Abstracts over the concrete type of Value. Needs to be refined by traits that
inherit from Domain and which extend Domain's Value trait.
A simple type alias of the type DomainValue; used to facilitate comprehension.
A simple type alias of the type DomainValue; used to facilitate comprehension.
A type alias for Iterables of ExceptionValues; used to facilitate comprehension.
A type alias for Iterables of ExceptionValues; used to facilitate comprehension.
Represents a value that has no well defined state/type.
Represents a value that has no well defined state/type. Such values are the result of a join of two incompatible values and are generally only found in registers (in the locals) and then identify a value that is dead.
org.opalj.ai.Domain.Value for further details.
Computation that returns a numeric value or an ObjectType.ArithmeticException.
Computation that returns a numeric value or an ObjectType.ArithmeticException.
An instruction's current register values/locals are represented using an array.
An instruction's current register values/locals are represented using an array.
An instruction's operands are represented using a list where the first element of the list represents the top level operand stack value.
An instruction's operands are represented using a list where the first element of the list represents the top level operand stack value.
Stores a single return address (i.e., a program counter/index into the code array).
Stores a single return address (i.e., a program counter/index into the code array).
Though the framework completely handles all aspects related to return address
values, it is nevertheless necessary that this class inherits from Value
as return addresses are stored on the stack/in the registers. However,
if the Value trait should be refined, all additional methods may – from
the point-of-view of OPAL-AI - just throw an OperationNotSupportedException
as these additional methods will never be called by OPAL-AI.
A collection of (not furhter stored) return address values.
A collection of (not furhter stored) return address values. Primarily used when we join the executions of subroutines.
Abstracts over a concrete operand stack value or a value stored in one of the local variables/registers.
Abstracts over a concrete operand stack value or a value stored in one of the local variables/registers.
In general, subclasses and users of a Domain should not have/declare
a direct dependency on Value. Instead they should use DomainValue as otherwise
extensibility of a Domain may be hampered or even be impossible. The only
exceptions are, of course, classes that directly inherit from this class.
If you directly extend/refine this trait (i.e., in a subclass of the Domain trait
you write something like trait Value extends super.Value), make sure that
you also extend all classes/traits that inherit from this type
(this may require a deep mixin composition and that you refine the type
DomainType accordingly).
However, OPAL was designed such that extending this class should – in general
– not be necessary. It may also be easier to encode the desired semantics – as
far as possible – as part of the domain.
Standard inheritance from this trait is always supported and is the primary mechanism to model an abstract domain's lattice w.r.t. some special type of value. In general, the implementation should try to avoid creating new instances of values unless strictly required to model the domain's semantics. This will greatly improve the overall performance as this framework heavily uses reference-based equality checks to speed up the evaluation.
OPAL does not rely on any special equality semantics w.r.t. values and
never directly or indirectly calls a Value's equals or eq method. Hence,
a domain can encode equality such that it best fits its need.
However, some of the provided domains rely on the following semantics for equals:
Two domain values have to be equal (==) iff they represent the same
information. This includes additional information, such as, the value of
the origin.
E.g., a value (AnIntegerValue) that represents an arbitrary Integer value
has to return true if the domain value with which it is compared also
represents an arbitrary Integer value (AnIntegerValue). However,
it may still be necessary to use multiple objects to represent an arbitrary
integer value if, e.g., constraints should be attached to specific values.
For example, after a comparison of an integer value with a predefined
value (e.g., AnIntegerValue < 4) it is possible to constrain the respective
value on the subsequent paths (< 4 on one path and >= 4 on the other path).
To make that possible, it is however necessary to distinguish the
AnIntegervalue from some other AnIntegerValue to avoid constraining
unrelated values.
public void foo(int a,int b) {
if(a < 4) {
z = a - 2 // here a is constrained (< 4), b and z are unconstrained
}
else {
z = a + 2 // here a is constrained (>= 4), b and z are unconstrained
}
} In general, equals is only defined for values belonging to the same
domain. If values need to be compared across domains, they need to be adapted
to a target domain first.
Creates a non-null object that represent a ArithmeticException and that has the
given origin.
Creates a non-null object that represent a ArithmeticException and that has the
given origin.
If the ArithmeticException was created by the VM while evaluating an instruction
with the program counter pc you use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Creates a non-null object that represent a ArrayIndexOutOfBoundsException and that has the
given origin.
Creates a non-null object that represent a ArrayIndexOutOfBoundsException and that has the
given origin.
If the ArrayIndexOutOfBoundsException was created by the VM while evaluating an instruction
with the program counter pc you use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Creates a non-null object that represent a ArrayStoreException and that has the
given origin.
Creates a non-null object that represent a ArrayStoreException and that has the
given origin.
If the ArrayStoreException was created by the VM while evaluating an instruction
with the program counter pc you use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Factory method to create a representation of a boolean value with the given initial value and origin.
Factory method to create a representation of a boolean value with the given initial value and origin.
The domain may ignore the information about the value and the origin (origin).
Factory method to create a representation of a boolean value if we know the origin of the value.
Factory method to create a representation of a boolean value if we know the origin of the value.
The domain may ignore the information about the origin (origin).
Factory method to create a DomainValue that represents the given byte value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents the given byte value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
The domain may ignore the information about the value and the origin (origin).
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
The domain may ignore the information about the origin (origin).
Factory method to create a DomainValue that represents the given char value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents the given char value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
The domain may ignore the information about the origin (origin).
Creates a non-null object that represent a ClassCastException and that has the
given origin.
Creates a non-null object that represent a ClassCastException and that has the
given origin.
If the ClassCastException was created by the VM while evaluating an instruction
with the program counter pc you use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Factory method to create a DomainValue that represents a runtime value of
type "Class<T>" and that was created by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents a runtime value of
type "Class<T>" and that was created by the instruction with the
specified program counter.
This function is called by OPAL when a class constant (LDC(_W) instruction) is
put on the stack.
The domain may ignore the information about the value and the origin (vo).
The properties of the domain value are:
The class tag can be used to create type safe arrays or to extract the concrete type of the domain value.
The class tag can be used to create type safe arrays or to extract the concrete type of the domain value.
val DomainReferenceValue(v) = value // of type "DomainValue" // v is now of the type DomainReferenceValue
The class tag for the type DomainValue.
The class tag for the type DomainValue.
Required to generate instances of arrays in which values of type
DomainValue can be stored in a type-safe manner.
In the sub-trait or class that fixes the type of DomainValue it is necessary
to implement this abstract val using:
val DomainValueTag : ClassTag[DomainValue] = implicitly(As of Scala 2.10 it is necessary that you do not use implicit in the subclass -
it will compile, but fail at runtime.)
Factory method to create a DomainValue that represents the given double value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents the given double value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
The domain may ignore the information about the value and the origin (vo).
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter, but where
we have no knowledge about the precise value.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter, but where
we have no knowledge about the precise value.
The domain may ignore the information about the origin (vo).
Factory method to create a DomainValue with the specified origin.
Factory method to create a DomainValue with the specified origin.
The origin is typically the program counter of the instruction
that created this value/where the value was observed for the first
time.
The domain may ignore the information about the origin (origin).
Factory method to create a DomainValue with the specified origin.
Factory method to create a DomainValue with the specified origin.
The origin is typically the program counter of the instruction
that created this value/where the value was observed for the first
time.
The domain may ignore the information about the origin (origin).
Creates a non-null object that represent an IllegalMonitorStateException and that has the
given origin.
Creates a non-null object that represent an IllegalMonitorStateException and that has the
given origin.
If the IllegalMonitorStateException was created by the VM while evaluating an instruction
with the program counter pc you should use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Factory method to create a DomainValue that represents an array
that was successfully created and which has the given type.
Factory method to create a DomainValue that represents an array
that was successfully created and which has the given type.
The domain may ignore the information about the origin (pc) and
the precise size of each dimension.
The properties of the domain value are:
Information about the origin of the value.
The size of each dimension if available. counts may not be empty but
may not contain information about all dimensions; the
following condition always has to hold: counts.length <= arrayType.dimensions.
Factory method to create a DomainValue that represents an initialized
reference value of the given type and that was created (explicitly or implicitly)
by the instruction with the specified program counter.
Factory method to create a DomainValue that represents an initialized
reference value of the given type and that was created (explicitly or implicitly)
by the instruction with the specified program counter.
The given type usually identifies a class type (not an interface type) that is
not abstract, but in some cases (e.g. consider java.awt.Toolkit())
it may be useful/meaningful to relax this requirement and to state that the
class precisely represents the runtime type – even
so the class is abstract. However, such decisions need to be made by the domain.
This method is used by the OPAL framework to create reference values that are normally
internally created by the JVM (in particular exceptions such as
NullPointExeception and ClassCastException). However, it can generally
be used to create initialized objects/arrays.
The properties of the domain value are:
null.)
Factory method to create a DomainValue that represents the given integer value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents the given integer value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
The domain may ignore the information about the value and the origin (origin).
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
The domain may ignore the information about the origin (origin).
Factory method to create a DomainValue that represents the given long value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents the given long value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
The domain may ignore the information about the value and the origin (vo).
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
The domain may ignore the information about the origin (vo).
The result of the merge of two incompatible values has
to be reported as a MetaInformationUpdate[DomainIllegalValue].
The result of the merge of two incompatible values has
to be reported as a MetaInformationUpdate[DomainIllegalValue].
Creates a non-null object that represent a NegativeArraySizeException and that has the
given origin.
Creates a non-null object that represent a NegativeArraySizeException and that has the
given origin.
If the NegativeArraySizeException was created by the VM while evaluating an instruction
with the program counter pc you use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Creates a new DomainValue that represents a new,
uninitialized instance of an object of the given type.
Creates a new DomainValue that represents a new,
uninitialized instance of an object of the given type. The object was
created by the (NEW) instruction with the specified program counter.
OPAL calls this method when it evaluates newobject instructions.
If the bytecode is valid a call of one of the object's constructors will
subsequently initialize the object.
The properties of the domain value are:
null.)
Instances of arrays are created by the newarray and
multianewarray instructions and in both cases an exception may be thrown
(e.g., NegativeArraySizeException).
Represents a non-null reference value with the given type as an upper type bound.
Represents a non-null reference value with the given type as an upper type bound.
The domain may ignore the information about the value and the origin (vo).
The properties of the domain value are:
null.)
Creates a non-null object that represent a NullPointerException and that has the
given origin.
Creates a non-null object that represent a NullPointerException and that has the
given origin.
If the NullPointerException was created by the VM while evaluating an instruction
with the program counter pc you should use the method ValueOriginForVMLevelValue to
translate that pc to the appropriate ValueOrigin.
Factory method to create a DomainValue that represents value null and
and that was created (explicitly or implicitly) by the instruction
with the specified program counter.
Factory method to create a DomainValue that represents value null and
and that was created (explicitly or implicitly) by the instruction
with the specified program counter.
The domain may ignore the information about the value and the origin (pc).
The properties of the domain value are:
Factory method to create a DomainValue that represents either a reference
value that has the given type and is initialized or the value null.
Factory method to create a DomainValue that represents either a reference
value that has the given type and is initialized or the value null. However, the
information whether the value is null or not is not available. Furthermore, the
type may also just be an upper bound.
The domain may ignore the information about the value and the origin, but it has to remain possible for the domain to identify the component type of an array.
The properties of the domain value are:
Factory method to create an instance of a ReturnAddressValue.
Factory method to create an instance of a ReturnAddressValue.
Factory method to create a DomainValue that represents the given short value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that represents the given short value
and that was created (explicitly or implicitly) by the instruction with the
specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
Factory method to create a DomainValue that was created (explicitly or
implicitly) by the instruction with the specified program counter.
The domain may ignore the information about the origin (origin).
Factory method to create a DomainValue that represents the given string value
and that was created by the instruction with the specified program counter.
Factory method to create a DomainValue that represents the given string value
and that was created by the instruction with the specified program counter.
This function is called by OPAL-AI when a string constant (LDC(_W) instruction) is
put on the stack.
The domain may ignore the information about the value and the origin (vo).
The properties of the domain value are:
null.A non-null string. (The string may be empty, though.)
The singleton instance of the IllegalValue.
The singleton instance of the IllegalValue.
The singleton instance of ReturnAddressValues
The singleton instance of ReturnAddressValues
Creates a non-null object that represent a Throwable object and that has the
given origin.
Creates a non-null object that represent a Throwable object and that has the
given origin.
If the Throwable was created by the VM while evaluating an instruction with
the program counter pc you should use the method ValueOriginForVMLevelValue
to translate that pc to the appropriate ValueOrigin.
Returns the array's length or throws a NullPointerException.
Returns the array's length or throws a NullPointerException.
Tests if the two given integer values are equal.
Tests if the two given integer values are equal.
A value with computational type integer.
A value with computational type integer.
Tests if the first integer value is smaller than the second value.
Tests if the first integer value is smaller than the second value.
A value with computational type integer.
A value with computational type integer.
Tests if the first integer value is less than or equal to the second value.
Tests if the first integer value is less than or equal to the second value.
A value with computational type integer.
A value with computational type integer.
Returns Yes iff at least one possible extension of the given
value is in the specified range; that is, if the intersection of the range of
values captured by the given value and the specified range is non-empty.
Returns Yes iff at least one possible extension of the given
value is in the specified range; that is, if the intersection of the range of
values captured by the given value and the specified range is non-empty.
For example, if the given value captures all positive integer values and the
specified range is [-1,1] then the answer has to be Yes. If we know nothing
about the potential extension of the given value the answer will be Unknown.
The answer is No iff both ranges are non-overlapping.
A value that has to be of computational type integer.
The range's lower bound (inclusive).
The range's upper bound (inclusive).
Returns Yes iff at least one (possible) extension of a given value is
not in the specified range; that is, if the set difference of the range of
values captured by the given value and the specified range is non-empty.
Returns Yes iff at least one (possible) extension of a given value is
not in the specified range; that is, if the set difference of the range of
values captured by the given value and the specified range is non-empty.
For example, if the given value has the integer value 10 and the
specified range is [0,Integer.MAX_VALUE] then the answer has to be No. But,
if the given value represents the range [-5,Integer.MAX_VALUE] and the specified
range is again [0,Integer.MAX_VALUE] then the answer has to be Yes.
The answer is Yes iff the analysis determined that at runtime value will have
a value that is not in the specified range. If the analysis(domain) is not able
to determine whether the value is or is not in the given range then the answer
has to be Unknown.
A value that has to be of computational type integer.
The range's lower bound (inclusive).
The range's upper bound (inclusive).
Tries to determine if the type referred to as subtype is a subtype of the
specified reference type supertype.
Tries to determine if the type referred to as subtype is a subtype of the
specified reference type supertype. If the class hierarchy is not complete
the answer may be Unknown.
Tries to determine – under the assumption that the given value is not
null – if the runtime type of the given reference value could be a
subtype of the specified reference type supertype.
Tries to determine – under the assumption that the given value is not
null – if the runtime type of the given reference value could be a
subtype of the specified reference type supertype. I.e., if the type of the
value is not precisely known, then all subtypes of the value's type are also
taken into consideration when analyzing the subtype relation and only if we
can guarantee that none is a subtype of the given supertype the answer will be
No.
The returned value is only meaningful if value does not represent
the runtime value null.
Add of two long values.
Add of two long values.
The pc of the add(+) instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
Boolean and of two long values.
Boolean and of two long values.
The pc of the "&" instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
Comparison (==) of two long values.
Comparison (==) of two long values.
The pc of the comparison instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
A domain value that encapsulates an integer value with the value -1,0 or 1.
Division of two long values.
Division of two long values.
The pc of the div (/) instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
The return value is the calculated value and/or (depending on the domain)
an ArithmeticException if value2 is 0.
Multiplication of two long values.
Multiplication of two long values.
The pc of the mul (/) instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
Negation of a long value.
Negation of a long value.
The pc of the neg instruction.
A long value (guaranteed by the JVM's semantics).
Boolean or of two long values.
Boolean or of two long values.
The pc of the "boolean or" (|) instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
Remainder of two long values.
Remainder of two long values.
The pc of the div (/) instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
The return value is the calculated value and/or (depending on the domain)
an ArithmeticException if value2 is 0.
Subtraction of two long values.
Subtraction of two long values.
The pc of the sub(-) instruction.
A long value (guaranteed by the JVM's semantics.)
A long value (guaranteed by the JVM's semantics.)
xor of two long values.
xor of two long values.
The pc of the "xor" instruction.
A long value (guaranteed by the JVM's semantics).
A long value (guaranteed by the JVM's semantics).
Creates a representation of a new multidimensional array.
Creates a representation of a new multidimensional array.
The return value is either a new array or a NegativeArraySizeException if
count is negative.
The return value is either a new array or a NegativeArraySizeException if
count is negative.
The return value is either a new array or a NegativeArraySizeException if
count is negative.
Compares the given values for reference equality.
Compares the given values for reference equality. Returns Yes if both values
point to the same instance and returns No if both objects are known not to
point to the same instance. The latter is, e.g., trivially the case when both
values have a different concrete type. Otherwise Unknown is returned.
If both values are representing the null value the org.opalj.Answer is Yes.
A value of computational type reference.
A value of computational type reference.
Determines whether the given value is null (Yes), maybe null (Unknown) or
is not null (No).
Determines whether the given value is null (Yes), maybe null (Unknown) or
is not null (No).
A value of computational type reference.
Called by the abstract interpreter when the type bound of the top most stack value needs to be refined.
Called by the abstract interpreter when the type bound of the top most stack
value needs to be refined. This method is only called by the abstract
interpreter iff an immediately preceding subtype query (typeOf(value) <: bound)
returned Unknown. This method must not be ignored – w.r.t. refining the top-most
stack value; it is e.g., used by org.opalj.br.instructions.CHECKCAST
instructions.
A domain that is able to identify aliases can use this information to propagate the information to the other aliases.
Sets the is null property of the top-most stack value to Yes.
Sets the is null property of the top-most stack value to Yes. This method is
called by the framework when the top-most operand stack value has to be null, but
a previous isNull check returned Unknown.
E.g., after a org.opalj.br.instructions.CHECKCAST that fails unless the
value is "null".
This method can be ignored; i.e., the return value can be (operands,locals).
However, a domain that is able to identify aliases can use this information to propagate
the information to the other aliases.
Creates the domain value that represents the constant field value.
Creates the domain value that represents the constant field value.
Creates a DomainValue that represents a value with the given type
and which is initialized using the JVM's default value for that type.
Creates a DomainValue that represents a value with the given type
and which is initialized using the JVM's default value for that type.
E.g., for IntegerValues the value is set to 0. In case of a
ReferenceType the value is the ReferenceValuesFactory#NullValue.
Factory method to create a representation of the integer constant value 0.
Factory method to create a representation of the integer constant value 0.
OPAL in particular uses this special value for performing subsequent computations against the fixed value 0 (e.g., for if_XX instructions).
(The origin (ValueOrigin) that is used is the ConstantValueOrigin to signify that this value was not created by the program.)
The domain may ignore the information about the value.
Called by the AI framework for each load constant method handle (org.opalj.br.instructions.LoadMethodHandle) instruction to get a representation of/a DomainValue that represents the handle.
Called by the AI framework for each load constant method handle (org.opalj.br.instructions.LoadMethodHandle) instruction to get a representation of/a DomainValue that represents the handle.
A valid method handle.
An InitializedObjectValue(ObjectType.MethodHandle).
Hence, this method needs to be overridden
if resolution of MethodHandle based method calls should be performed.
Called by the framework for each load constant method type
(org.opalj.br.instructions.LoadMethodType) instruction to
get a domain-specific representation of the method descriptor as a MethodType.
Called by the framework for each load constant method type
(org.opalj.br.instructions.LoadMethodType) instruction to
get a domain-specific representation of the method descriptor as a MethodType.
A valid method descriptor.
An InitializedObjectValue(ObjectType.MethodType).
Hence, this method needs to be overridden
if resolution of MethodType based method calls should be performed.
The result of merging two values should never be reported as a
StructuralUpdate if the computed value is an IllegalValue.
The result of merging two values should never be reported as a
StructuralUpdate if the computed value is an IllegalValue. The JVM semantics guarantee
that the value will not be used and, hence, continuing the interpretation is meaningless.
This method is solely defined for documentation purposes and to catch implementation errors early on.
Factory method to create domain values with a specific type.
Factory method to create domain values with a specific type. I.e., values for
which we have some type information but no precise value or source information.
However, the value is guaranteed to be null or properly initialized.
For example, if valueType is a reference type it may be possible
that the actual value is null, but such knowledge is not available.
The framework uses this method when a method is to be analyzed, but no parameter values are given and initial values need to be generated. This method is not used elsewhere by the framework.
Called by the abstract interpreter when an exception is thrown that is not (guaranteed to be) handled within the same method.
Called by the abstract interpreter when an exception is thrown that is not (guaranteed to be) handled within the same method.
If the original exception value is null (/*E.g.*/throw null;), then
the exception that is actually thrown is a new NullPointerException. This
situation is, however, completely handled by OPAL and the exception value
is hence never null.
Called by the abstract interpreter when the abstract interpretation of a method has ended.
Called by the abstract interpreter when the abstract interpretation of a method has ended. The abstract interpretation of a method ends if either the fixpoint is reached or the interpretation was aborted.
By default this method does nothing.
Domains that override this method are expected to also call
super.abstractInterpretationEnded(aiResult).
This method is called after all values which differ have been joined, but before
joinPostProcessing will be called.
This method is called after all values which differ have been joined, but before
joinPostProcessing will be called.
This methods is called after the evaluation of the instruction with
the given pc with respect to targetPC, but before the values are propagated
(joined) and before it is checked whether the interpretation needs to be continued.
This methods is called after the evaluation of the instruction with
the given pc with respect to targetPC, but before the values are propagated
(joined) and before it is checked whether the interpretation needs to be continued.
I.e., if the operands (newOperands) or locals (newLocals) are further refined
then the refined operands and locals are joined (if necessary).
During the evaluation of the instruction it is possible that this method
is called multiple times with different targetPCs. The latter is not only
true for control flow instructions, but also for those instructions
that may raise an exception.
This method can and is intended to be overridden to further refine the operand
stack/the locals. However, the overriding method should always forward the (possibly
refined) operands and locals to the super method (stackable traits).
The given value, which is a value with computational type reference, is returned
by the return instruction with the given pc.
The given value, which is a value with computational type reference, is returned
by the return instruction with the given pc.
This method is called immediately before a join operation with regard
to the specified pc is performed.
This method is called immediately before a join operation with regard
to the specified pc is performed.
This method is intended to be overwritten by clients to perform custom operations.
The given value, which is a value with computational type double, is returned
by the return instruction with the given pc.
The given value, which is a value with computational type double, is returned
by the return instruction with the given pc.
Called by the framework after evaluating the instruction with the given pc.
Called by the framework after evaluating the instruction with the given pc. I.e., the state of all potential successor instructions was updated and the flow method was called – potentially multiple times – accordingly.
By default this method does nothing.
Called by the framework after performing a computation to inform the domain about the result.
Called by the framework after performing a computation to inform the domain
about the result.
That is, after evaluating the effect of the instruction with currentPC on the current
stack and register and (if necessary) joining the updated stack and registers with the stack
and registers associated with the instruction successorPC. (Hence, this method
is ONLY called for return instructions if the return instruction throws an
IllegalMonitorStateException.)
This function basically informs the domain about the instruction that
may be evaluated next. The flow function is called for every possible
successor of the instruction with currentPC. This includes all branch
targets as well as those instructions that handle exceptions.
In some cases it will even be the case that flow is called multiple times with
the same pair of program counters: (currentPC, successorPC). This may happen,
e.g., in case of a switch instruction where multiple values have the same
body/target instruction and we do not have precise information about the switch value.
E.g., as in the following snippet:
switch (i) { // pc: X => Y (for "1"), Y (for "2"), Y (for "3")
case 1:
case 2:
case 3: System.out.println("Great."); // pc: Y
default: System.out.println("Not So Great."); // pc: Z
}The flow function is also called after instructions that are domain independent
such as dup and load instructions which just manipulate the registers
and stack in a generic way.
This enables the domain to precisely follow the evaluation
progress and in particular to perform control-flow dependent analyses.
The program counter of the instruction that is currently evaluated by the abstract interpreter.
The current operands. I.e., the operand stack before the instruction is evaluated.
The current locals. I.e., the locals before the instruction is evaluated.
The program counter of an instruction that is a potential
successor of the instruction with currentPC. In general the AI framework
adds the pc of the successor instruction to the beginning of the worklist
unless it is a join instruction. In this case the pc is added to the end – in
the context of the current (sub)routine. Hence, the AI framework first evaluates
all paths leading to a join instruction before the join instruction will
be evaluated.
Yes if the successor instruction is or was scheduled.
I.e., Yes is returned if the worklist contains successorPC, No if the
worklist does not contain successorPC. Unknown is returned if the AI
framework did not process the worklist and doesn't know anything about
the scheduled successors. Note that this value is independent of the
subroutine in which the value may be scheduled. If an implementation schedules
successorPC the the super call has to set isSuccessorScheduled to Yes.
true if and only if the evaluation of
the instruction with the program counter currentPC threw an exception;
false otherwise. Hence, if this parameter is true the instruction
with successorPC is the first instruction of the handler.
> 0 if and only if we have an exceptional
control flow that terminates one or more subroutines.
In this case the successor instruction is scheduled (if at all) after all
subroutines that will be terminated by the exception.
true if a join was performed. I.e., the successor
instruction is an instruction (Code.cfJoins) that was already
previously evaluated and where multiple paths potentially join.
The current list of instructions that will be evaluated next.
If you want to force the evaluation of the instruction
with the program counter successorPC it is sufficient to test whether
the list already contains successorPC and – if not – to prepend it.
If the worklist already contains successorPC then the domain is allowed
to move the PC to the beginning of the worklist.
If the PC does not belong to the same (current) (sub)routine, it is not allowed to be moved to the beginning of the worklist. (Subroutines can only be found in code generated by old Java compilers; before Java 6. Subroutines are identified by jsr/ret instructions. A subroutine can be identified by going back in the worklist and by looking for specific "program counters" (e.g., SUBROUTINE_START, SUBROUTINE_END). These program counters mark the beginning of a subroutine. In other words, an instruction can be freely moved around unless a special program counter value is found. All special program counters use negative values. Additionally, neither the negative values nor the positive values between two negative values should be changed. Furthermore, no value (PC) should be put between negative values that capture subroutine information. If the domain updates the worklist, it is the responsibility of the domain to call the tracer and to inform it about the changes. Note that the worklist is not allowed to contain duplicates related to the evaluation of the current (sub-)routine.
The array that associates every instruction with its
operand stack that is in effect. Note, that only those elements of the
array contain values that are related to instructions that were
evaluated in the past; the other elements are null. Furthermore,
it identifies the operandsArray of the subroutine that will execute the
instruction with successorPC.
The operandsArray may be null for the current instruction (not the successor
instruction) if the execution of the current instruction leads to the termination
of the current subroutine. In this case the information about the operands
and locals associated with all instructions belonging to the subroutine is
reset.
The array that associates every instruction with its current
register values. Note, that only those elements of the
array contain values that are related to instructions that were evaluated in
the past. The other elements are null. Furthermore,
it identifies the localsArray of the subroutine that will execute the
instruction with successorPC.
The localsArray may be null for the current instruction (not the successor
instruction) if the execution of the current instruction leads to the termination
of the current subroutine. In this case the information about the operands
and locals associated with all instructions belonging to the subroutine is
reset.
The updated worklist. In most cases this is simply the given worklist.
The default case is also to return the given worklist.
A method that overrides this method must always call the super method to ensure that every domain that uses this hook gets informed about a flow.
,The domain is allowed to modify the worklist, operandsArray and
localsArray. However, the AI will not perform any checks. In case of
updates of the operandsArray or localsArray it is necessary to first
create a shallow copy before updating it.
If this is not done, it may happen that the locals associated
with other instructions are also updated.
The given value, which is a value with computational type float, is returned
by the return instruction with the given pc.
The given value, which is a value with computational type float, is returned
by the return instruction with the given pc.
Returns the field's value and/or a new NullPointerException if the given
objectref represents the value null.
Returns the field's value and/or a new NullPointerException if the given
objectref represents the value null.
The field's value or a new NullPointerException.
Returns the field's value.
Returns the field's value.
Tests if the two given integer values are not equal.
Tests if the two given integer values are not equal.
A value with computational type integer.
A value with computational type integer.
This function is ONLY defined if a corresponding test (value1 == value2)
returned org.opalj.Unknown. I.e., this method is only allowed to be
called if there is something to establish!
I.e., the domain values are real ranges (not single values, e.g., [1,1])
that overlap.
This function is ONLY defined if a corresponding test (value1 != value2)
returned org.opalj.Unknown. I.e., this method is only allowed to be
called if there is something to establish!
I.e., the domain values are real ranges (not single values, e.g., [1,1])
that overlap.
This function is ONLY defined if a corresponding test (value1 < value2)
returned org.opalj.Unknown. I.e., this method is only allowed to be
called if there is something to establish!
I.e., the domain values are real ranges (not single values, e.g., [1,1])
that overlap.
This function is ONLY defined if a corresponding test (value1 <= value2)
returned org.opalj.Unknown. I.e., this method is only allowed to be
called if there is something to establish!
I.e., the domain values are real ranges (not single values, e.g., [1,1])
that overlap.
Sets the given domain value to theValue.
Sets the given domain value to theValue.
This function is called by OPAL before it starts to explore the branch where this condition has to hold. (This function is, e.g., called whenever we explore the branches of a switch-case statement.) I.e., the constraint is established before a potential join operation.
An integer domain value that does also, but not exclusively represents
theValue.
Tests if the given integer value is 0 or maybe 0.
Tests if the given integer value is 0 or maybe 0.
A value with computational type integer.
Tests if the first integer value is larger than the second value.
Tests if the first integer value is larger than the second value.
A value with computational type integer.
A value with computational type integer.
Tests if the given integer value is > 0 or maybe > 0.
Tests if the given integer value is > 0 or maybe > 0.
A value with computational type integer.
Tests if the first integer value is larger than or equal to the second value.
Tests if the first integer value is larger than or equal to the second value.
A value with computational type integer.
A value with computational type integer.
Tests if the given value is greater than or equal to 0 or maybe greater than or equal to 0.
Tests if the given value is greater than or equal to 0 or maybe greater than or equal to 0.
A value with computational type integer.
Tests if the given integer value is < 0 or maybe < 0.
Tests if the given integer value is < 0 or maybe < 0.
A value with computational type integer.
Tests if the given integer value is less than or equal to 0 or maybe less than or equal to 0.
Tests if the given integer value is less than or equal to 0 or maybe less than or equal to 0.
A value with computational type integer.
Tests if the given integer value is not 0 or maybe not 0.
Tests if the given integer value is not 0 or maybe not 0.
A value with computational type integer.
The given value, which is a value with computational type integer, is returned
by the return instruction with the given pc.
The given value, which is a value with computational type integer, is returned
by the return instruction with the given pc.
Joins the given operand stacks and local variables.
Joins the given operand stacks and local variables.
In general there should be no need to refine this method. Overriding this method should only be done for analysis purposes.
This method heavily relies on reference comparisons to speed up the overall process of performing an abstract interpretation of a method. Hence, a computation should – whenever possible – return (one of) the original object(s) if that value has the same abstract state as the result. Furthermore, if all original values capture the same abstract state as the result of the computation, the "left" value/the value that was already used in the past should be returned.
The joined operand stack and registers.
Returns NoUpdate if this memory layout already subsumes the
other memory layout.
The operand stacks are guaranteed to contain compatible values w.r.t. the
computational type (unless the bytecode is not valid or OPAL contains
an error). I.e., if the result of joining two operand stack values is an
IllegalValue we assume that the domain implementation is incorrect.
However, the joining of two register values can result in an illegal value -
which identifies the value as being dead.
The size of the operands stacks that are to be joined and the number of registers/locals that are to be joined can be expected to be identical under the assumption that the bytecode is valid and the framework contains no bugs.
Enables the customization of the behavior of the base join method.
Enables the customization of the behavior of the base join method.
This method in particular enables, in case of a MetaInformationUpdate, to raise the update type to force the continuation of the abstract interpretation process.
Methods should always override this method and should call the super method.
The current update type. The level can be raised. It is an error to lower the update level.
The old operands, before the join. Should not be changed.
The old locals, before the join. Should not be changed.
The new operands; may be updated.
The new locals; may be updated.
The pc of the jsr(w) instruction.
Conversion of the given long value to a double value.
Conversion of the given long value to a double value.
Conversion of the given long value to a float value.
Conversion of the given long value to a float value.
Conversion of the given long value to an integer value.
Conversion of the given long value to an integer value.
The given value, which is a value with computational type long, is returned
by the return instruction with the given pc.
The given value, which is a value with computational type long, is returned
by the return instruction with the given pc.
Shift left of a long value.
Shift left of a long value.
The pc of the "shift left" instruction.
A long value (guaranteed by the JVM's semantics).
A int value (guaranteed by the JVM's semantics) that determines the number of bits to shift.
Shift right of a long value.
Shift right of a long value.
The pc of the "shift right" instruction.
A long value (guaranteed by the JVM's semantics).
An int value (guaranteed by the JVM's semantics) that determines the number of bits to shift.
Unsigned shift right of a long value.
Unsigned shift right of a long value.
The pc of the "unsigned shift right" instruction.
A long value (guaranteed by the JVM's semantics).
A int value (guaranteed by the JVM's semantics) that determines the number of bits to shift.
Merges the given domain value v1 with the domain value v2 and returns
the merged value which is v1 if v1 is an abstraction of v2, v2 if v2
is an abstraction of v1 or some other value if a new value is computed that
abstracts over both values.
Merges the given domain value v1 with the domain value v2 and returns
the merged value which is v1 if v1 is an abstraction of v2, v2 if v2
is an abstraction of v1 or some other value if a new value is computed that
abstracts over both values.
This operation is commutative.
Handles a monitorenter instruction.
Handles a monitorenter instruction.
A monitor enter instruction may throw a NullPointerException.
Handles a monitorexit instruction.
Handles a monitorexit instruction.
A monitor exit instruction may throw a NullPointerException or an
IllegalMonitorStateException.
Returns a string representation of the properties associated with the instruction with the respective program counter.
Returns a string representation of the properties associated with the instruction with the respective program counter.
Associating properties with an instruction and maintaining those properties
is, however, at the sole responsibility of the Domain.
This method is predefined to facilitate the development of support tools and is not used by the abstract interpretation framework.
Domains that define (additional) properties should (abstract) override
this method and should return a textual representation of the property.
Sets the field's value if the given objectref is not null(in the Domain).
Sets the field's value if the given objectref is not null(in the Domain).
In the latter case a NullPointerException is thrown.
Sets the field's value.
Sets the field's value.
Compares the given values for reference inequality.
Compares the given values for reference inequality. Returns No if both values
point to the same instance and returns Yes if both objects are known not to
point to the same instance. The latter is, e.g., trivially the case when both
values have a different concrete type. Otherwise Unknown is returned.
If both values are representing the null value the org.opalj.Answer is Yes.
A value of computational type reference.
A value of computational type reference.
Called by OPAL when two values were compared for reference equality and we are going to analyze the branch where the comparison succeeded.
Called by OPAL when two values were compared for reference equality and we are going to analyze the branch where the comparison succeeded.
Called by OPAL when two values were compared for reference equality and we are going to analyze the branch where the comparison failed.
Called by OPAL when two values were compared for reference equality and we are going to analyze the branch where the comparison failed.
Called by OPAL-AI when it establishes that the value is guaranteed not to be null.
Called by OPAL-AI when it establishes that the value is guaranteed not to be null.
E.g., after a comparison with null OPAL can establish that the
value has to be null on one branch and that the value is not null on the
other branch.
Called by the framework when the value is known to be null/has to be null.
Called by the framework when the value is known to be null/has to be null.
E.g., after a comparison with null (IFNULL/IFNONNULL) OPAL-AI knows that the
value has to be null on one branch and that the value is not null on the
other branch.
Returns Yes if given value is never null, Unknown if the values is maybe
null and No otherwise.
Returns Yes if given value is never null, Unknown if the values is maybe
null and No otherwise.
A value of computational type reference.
The pc of the ret instruction.
Called when a return instruction with the given pc is reached.
Called when a return instruction with the given pc is reached.
In other words, when the method returns normally.
This function can be called when the instruction successorPC needs to be
scheduled.
This function can be called when the instruction successorPC needs to be
scheduled. The function will test if the instruction is already scheduled and
– if so – returns the given worklist. Otherwise the instruction
is scheduled in the correct (subroutine-)context.
Creates a summary of the given domain values by summarizing and
joining the given values.
Creates a summary of the given domain values by summarizing and
joining the given values. For the precise details
regarding the calculation of a summary see Value.summarize(...).
The program counter that will be used for the summary value if a new value is returned that abstracts over/summarizes the given values.
An Iterable over one or more values.
The current algorithm is generic and should satisfy most needs, but it is not very efficient. However, it should be easy to tailor it for a specific domain/domain values, if need be.
If true, all instructions that may raise an arithmetic exception (e.g., idiv,
ldiv) should do so if it is impossible to statically determine that no
exception will occur.
If true, all instructions that may raise an arithmetic exception (e.g., idiv,
ldiv) should do so if it is impossible to statically determine that no
exception will occur. But, if we can statically determine that the operation will
raise an exception then the exception will be thrown – independently of this
setting. Furthermore, if we can statically determine that no exception will be
raised, no exception will be thrown. Hence, this setting only affects computations
with values with incomplete information.
If true an ArrayIndexOutOfBoundsException is thrown if the index cannot
be verified to be valid.
If true an ArrayIndexOutOfBoundsException is thrown if the index cannot
be verified to be valid.
If true an ArrayStoreException is thrown if it cannot be verified that the
value can be stored in the array.
If true an ArrayStoreException is thrown if it cannot be verified that the
value can be stored in the array.
If true a ClassCastException is thrown by CHECKCAST instructions if it
cannot be verified that no ClassCastException will be thrown.
If true a ClassCastException is thrown by CHECKCAST instructions if it
cannot be verified that no ClassCastException will be thrown.
Throw a ClassNotFoundException if the a specific reference type is not
known in the current context.
Throw a ClassNotFoundException if the a specific reference type is not
known in the current context. The context is typically a specific Project.
Determines the behavior how method calls are handled where the exceptions that the called method may throw are unknown.
Determines the behavior how method calls are handled where the exceptions that the called method may throw are unknown.
If true then monitorexit and the (XXX)return instructions will throw
IllegalMonitorStateExceptions unless the analysis is able to determine that
the exception is guaranteed to be raised.
If true then monitorexit and the (XXX)return instructions will throw
IllegalMonitorStateExceptions unless the analysis is able to determine that
the exception is guaranteed to be raised.
If true a NegativeArraySizeException is thrown if the index cannot be
verified to be positive.
If true a NegativeArraySizeException is thrown if the index cannot be
verified to be positive.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored. However, if the interpreter
identifies a situation in which a NullPointerException is guaranteed to be
thrown, it will be thrown.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored. However, if the interpreter
identifies a situation in which a NullPointerException is guaranteed to be
thrown, it will be thrown.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored. However, if the interpreter
identifies a situation in which a NullPointerException is guaranteed to be
thrown, it will be thrown. Example:
def demo(o : Object) { o.toString // - If "true", a NullPointerException will ALSO be thrown; // the operation also succeeds. // - If "false" the operation will "just" succeed }
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored.
Returns true if potential NullPointerExceptions should be thrown and false
if such NullPointerExceptions should be ignored. However, if the interpreter
identifies a situation in which a NullPointerException is guaranteed to be
thrown, it will be thrown.
If true a NullPointerExceptions is thrown if the exception that is to be
thrown is not not known to be null.
If true a NullPointerExceptions is thrown if the exception that is to be
thrown is not not known to be null.
Returns the type(type bounds) of the given value.
Returns the type(type bounds) of the given value.
In general a single value can have multiple type bounds which depend on the
control flow.
However, all types that the value represents must belong to the same
computational type category. I.e., it is possible that the value either has the
type "NullPointerException or IllegalArgumentException", but it will never have
– at the same time – the (Java) types int and long. Furthermore,
it is possible that the returned type(s) is(are) only an upper bound of the
real type unless the type is a primitive type.
This default implementation always returns org.opalj.ai.UnknownType.
typeOfValueThis method is typically not implemented by a single Domain trait/object, but is
instead implemented collaboratively by all domains that implement the semantics
of certain values. To achieve that, other Domain traits that implement a
concrete domain's semantics have to abstract override this method and only
return the value's type if the domain knows anything about the type. If a method
that overrides this method has no knowledge about the given value, it should
delegate this call to its super method.
Example
trait FloatValues extends Domain[...] { ... abstract override def typeOfValue(value: DomainValue): TypesAnswer = value match { case r: FloatValue ⇒ IsFloatValue case _ ⇒ super.typeOfValue(value) } }
Replaces all occurrences of oldValue (using reference-quality) with newValue.
Replaces all occurrences of oldValue (using reference-quality) with newValue. If no
occurrences are found, the original operands and locals data structures
are returned.
Can be mixed in to create a
Domainthat is intended to be used to coordinate the exchange of values between different domains.This domain does not prescribe the semantics of any values, but instead implements methods that perform computations.
This domain directly inherits from Domain and can, thus, directly be used to create a final domain.
Core Properties