Package it.unive.lisa.program.cfg.statement

Class Expression

java.lang.Object

it.unive.lisa.program.cfg.statement.Statement

it.unive.lisa.program.cfg.statement.Expression

All Implemented Interfaces:

ProgramPoint, CodeElement, Node<Statement,Edge,CFG>, java.lang.Comparable<Statement>

Direct Known Subclasses:

AccessGlobal, AccessInstanceGlobal, BinaryExpression, Call, Literal, VariableRef

public abstract class Expression
extends Statement

An expression that is part of a statement of the program.

Field Summary

Fields inherited from class it.unive.lisa.program.cfg.statement.Statement

offset

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Expression(CFG cfg, CodeLocation location)	Builds an untyped expression happening at the given source location, that is its type is Untyped.INSTANCE.
protected	Expression(CFG cfg, CodeLocation location, Type staticType)	Builds a typed expression happening at the given source location.

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object obj)
Type	getDynamicType()	Yields the dynamic type of this expression, that is, the most specific common supertype of all its runtime types (available through getRuntimeTypes().
java.util.Collection<Identifier>	getMetaVariables()	Yields the meta variables that are generated by the evaluation of this expression.
Statement	getParentStatement()	Yields the Statement that contains this expression, if any.
Statement	getRootStatement()	Yields the outer-most Statement containing this expression, that is used as a node in the cfg.
ExternalSet<Type>	getRuntimeTypes()	The concrete types that this expression can have at runtime.
Type	getStaticType()	Yields the static type of this expression.
int	hashCode()
void	setParentStatement(Statement st)	Sets the Statement that contains this expression.
void	setRuntimeTypes(ExternalSet<Type> runtimeTypes)	Sets the runtime types of this expression.

Methods inherited from class it.unive.lisa.program.cfg.statement.Statement

compareTo, getCFG, getLocation, getOffset, semantics, stopsExecution, throwsError, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.unive.lisa.util.datastructures.graph.Node

accept, setOffset

Constructor Detail

Expression

protected Expression(CFG cfg,
                     CodeLocation location)

Builds an untyped expression happening at the given source location, that is its type is Untyped.INSTANCE.

Parameters:

cfg - the cfg that this expression belongs to

location - the location where the expression is defined within the source file. If unknown, use null

Expression

protected Expression(CFG cfg,
                     CodeLocation location,
                     Type staticType)

Builds a typed expression happening at the given source location.

Parameters:

cfg - the cfg that this expression belongs to

location - the location where this expression is defined within the source file. If unknown, use null

staticType - the static type of this expression

Method Detail

getStaticType

public final Type getStaticType()

Yields the static type of this expression.

Returns:

the static type of this expression

setRuntimeTypes

public final void setRuntimeTypes(ExternalSet<Type> runtimeTypes)

Sets the runtime types of this expression.

Parameters:

runtimeTypes - the set of concrete types that this expression can have at runtime

getRuntimeTypes

public final ExternalSet<Type> getRuntimeTypes()

The concrete types that this expression can have at runtime. If type inference has not been executed, this method returns a singleton set containing the static type of this expression.

Returns:

the set of runtime types

getDynamicType

public final Type getDynamicType()

Yields the dynamic type of this expression, that is, the most specific common supertype of all its runtime types (available through getRuntimeTypes().

Returns:

the dynamic type of this expression

getMetaVariables

public java.util.Collection<Identifier> getMetaVariables()

Yields the meta variables that are generated by the evaluation of this expression. These should be removed as soon as the values computed by those gets out of scope (e.g., popped from the stack). The returned collection will be filled while evaluating this expression Statement.semantics(AnalysisState, it.unive.lisa.interprocedural.InterproceduralAnalysis, StatementStore), thus invoking this method before computing the semantics will yield an empty collection.

Returns:

the meta variables

hashCode

public int hashCode()

Overrides:

hashCode in class Statement

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class Statement

setParentStatement

public final void setParentStatement(Statement st)

Sets the Statement that contains this expression.

Parameters:

st - the containing statement

getParentStatement

public final Statement getParentStatement()

Yields the Statement that contains this expression, if any. If this method returns null, than this expression is used as a command: it is the root statement of a node in the cfg, and its returned value is discarded.

Returns:

the statement that contains this expression, if any

getRootStatement

public final Statement getRootStatement()

Yields the outer-most Statement containing this expression, that is used as a node in the cfg. If this expression is used a command, then this method return this.

Returns:

the outer-most statement containing this expression, or this