Package it.unive.lisa.symbolic.heap

Class HeapExpression

java.lang.Object

it.unive.lisa.symbolic.SymbolicExpression

it.unive.lisa.symbolic.heap.HeapExpression

All Implemented Interfaces:

ScopedObject<SymbolicExpression>

Direct Known Subclasses:

AccessChild, HeapDereference, HeapReference, MemoryAllocation

public abstract class HeapExpression
extends SymbolicExpression

A symbolic expression that identifies a location in the program's heap. Instances of this expressions must be rewritten by HeapDomains to a ValueExpression before being evaluated from a ValueDomain.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	HeapExpression(Type type, CodeLocation location)	Builds the heap expression.

Method Summary

Modifier and Type	Method	Description
boolean	mightNeedRewriting()	Yields whether or not this expression can be considered safe to be processed by domains that only focus on ValueExpressions, or if it might need rewriting.
SymbolicExpression	popScope(ScopeToken token)	Pops the scope identified by the given token from the expression.
SymbolicExpression	pushScope(ScopeToken token)	Pushes a new scope, identified by the give token, in the expression.

Methods inherited from class it.unive.lisa.symbolic.SymbolicExpression

accept, equals, getCodeLocation, getStaticType, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

HeapExpression

protected HeapExpression(Type type,
                         CodeLocation location)

Builds the heap expression.

Parameters:

type - the static types of this expression

location - the code location of the statement that has generated this heap expression

Method Detail

pushScope

public SymbolicExpression pushScope(ScopeToken token)

Description copied from class: SymbolicExpression

Pushes a new scope, identified by the give token, in the expression. This causes all Identifiers where Identifier.canBeScoped() holds to become OutOfScopeIdentifiers associated with the given token.

Specified by:

pushScope in interface ScopedObject<SymbolicExpression>

Specified by:

pushScope in class SymbolicExpression

Parameters:

token - the token identifying the scope to push

Returns:

a copy of this expression where the local variables have gone out of scope

popScope

public SymbolicExpression popScope(ScopeToken token)
                            throws SemanticException

Description copied from class: SymbolicExpression

Pops the scope identified by the given token from the expression. This causes all the invisible variables (i.e. OutOfScopeIdentifiers) mapped to the given scope to become visible (e.g. Variables) again. Note that invoking this method on Identifiers where Identifier.canBeScoped() holds will return null if (i) the identifier is not scoped, or (ii) the identifier is scoped by a different token.

Specified by:

popScope in interface ScopedObject<SymbolicExpression>

Specified by:

popScope in class SymbolicExpression

Parameters:

token - the token of the scope to be restored

Returns:

a copy of this expression where the local variables associated with the given scope are visible again

Throws:

SemanticException - if an error occurs during the computation

mightNeedRewriting

public final boolean mightNeedRewriting()

Description copied from class: SymbolicExpression

Yields whether or not this expression can be considered safe to be processed by domains that only focus on ValueExpressions, or if it might need rewriting. This is a definite answer: if this method returns true, than this expression is sure to not contain anything that deals with, or points to, the memory.

Specified by:

mightNeedRewriting in class SymbolicExpression

Returns:

whether or not this expression might need rewriting