coins.alias
Class Tag

java.lang.Object
  coins.alias.Tag

class Tag

extends java.lang.Object

A Tag corresponds to some area in memory. It is assciated with the set of lvalue expressions that have the same form. So this could have extended ExpId, but instead has a field that links to the ExpId (MyExpId) it represents.

Tags form a tree structure in which parent nodes represent areas in memory that includes the areas child nodes represent. This relationship is used to assign bits to each Tag. It also makes it possible, via promote() method, to accurately handle the situation where some area obsuring operations, such as pointer arithmetic, hss been performed.

Field Summary

(package private) static int	ANCHORED Flag number for anchoredness.
(package private) int	fBitPos Bit position this Tag correponds to in the TagVectors to be created.
(package private) java.util.List	fChildren List of child Tags of this Tag.
(package private) boolean	fIsUnique Specifies if this Tag represents a unique area in memory.
(package private) int	fKind Kind of this Tag.
(package private) MyExpId	fMyExpId MyExpId object this Tag is associated with.
(package private) Tag	fParent Parent Tag of this Tag.
(package private) int	fStorageClass Storage class of this Tag.
(package private) TagVector	fTagVect TagVector object that represents all the objects this Tag may represnt.
(package private) Type	fType Type of the object this Tag represents.
(package private) Tag	fUnionAncestor
(package private) static int	HAS_UNION_ANCESTOR Flag number for whether being a union descendant.
(package private) static int	KIND_ATOMIC The kind for the Tags that represent atomic (scalar) type objects.
(package private) static int	KIND_STRUCT The kind for the Tags that represent struct type objects.
(package private) static int	KIND_UNION The kind for the Tags that represent union type objects.
(package private) static int	KIND_UNKNOWN The kind for the Tag whose type is unknown,
(package private) static int	KIND_VECTOR The kind for the Tags represent vector type objects.
(package private) static int	STO_CUR_FRAME Current frmae storage class, the storage class that corresponds to automatic variables declared within the current subprogram.
(package private) static int	STO_HEAP Heap storage class, the storage class that corresponds to areas allocated by the current subprogram.
(package private) static int	STO_OTHER Other storage class, the storage class that does not fall into current frame or static or heap.
(package private) static int	STO_ROOT Root storage class, the storage class that corresponds to the whole memory space.
(package private) static int	STO_STATIC Static storage class, the storage class that corresponds to static Vars.

Constructor Summary

(package private)	Tag(HIR pmallocInvocationNode) Creates a new instance of Tag that is associated with an area allocated by a single malloc invocation.
(package private)	Tag(int pKind) Creates a new instance of Tag that corresponds to the STO_OTHER storage class.
(package private)	Tag(MyExpId pMyExpId, boolean pIsAnchored, int pKind, int pStorageClass) Creates a new instance of Tag that is associated with a MyExpId object.

Method Summary

(package private) boolean	getFlag(int pFlag)
(package private) void	inheritAttributes() Inherits attributes from the parent Tag.
(package private) boolean	isAnchored() Returns true if this Tag has a corresponding anchor.
(package private) Tag	promote() Returns the Tag that covers the area that the result of the pointer operation that has a pointer expression that points to one of the areas that this Tag represents as one of its operands can point to.
(package private) void	setFlag(int pFlag, boolean pYesNo)
java.lang.String	toString() Returns the String representation of this Tag.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

fMyExpId

MyExpId fMyExpId

MyExpId object this Tag is associated with.

fKind

int fKind

Kind of this Tag. See the static fields of the names KIND_**** of this class.

fStorageClass

int fStorageClass

Storage class of this Tag.

fType

Type fType

Type of the object this Tag represents. Tags that represent

fBitPos

int fBitPos

Bit position this Tag correponds to in the TagVectors to be created. -1 if there is no such corresponding bit.

fIsUnique

boolean fIsUnique

Specifies if this Tag represents a unique area in memory. A Tag associated with a Var or constant-subscript element of an array Var or malloced area is unique.

fParent

Tag fParent

Parent Tag of this Tag. The parent Tag of a Tag corresponds to the area in memory that directly encloses the area the original Tag represents. As such, the original Tag must represent a relatively limited area in memory (isAnchored), or fAnchored is null. See #fChildren See #isAnchored

fChildren

java.util.List fChildren

List of child Tags of this Tag. A child Tag of a Tag corresponds to an area in memory that is directly enclosed by the area the original Tag represnts. As such, the original Tag must represent a relatively limited area in memory (isAnchored), or fChildren is empyt. See #fParent See #isAnchored

fUnionAncestor

Tag fUnionAncestor

KIND_VECTOR

static final int KIND_VECTOR

The kind for the Tags represent vector type objects.

See Also:

Constant Field Values

KIND_STRUCT

static final int KIND_STRUCT

The kind for the Tags that represent struct type objects.

See Also:

Constant Field Values

KIND_UNION

static final int KIND_UNION

The kind for the Tags that represent union type objects.

See Also:

Constant Field Values

KIND_ATOMIC

static final int KIND_ATOMIC

The kind for the Tags that represent atomic (scalar) type objects.

See Also:

Constant Field Values

KIND_UNKNOWN

static final int KIND_UNKNOWN

The kind for the Tag whose type is unknown,

See Also:

Constant Field Values

STO_ROOT

static final int STO_ROOT

Root storage class, the storage class that corresponds to the whole memory space.

See Also:

Constant Field Values

STO_CUR_FRAME

static final int STO_CUR_FRAME

Current frmae storage class, the storage class that corresponds to automatic variables declared within the current subprogram.

See Also:

Constant Field Values

STO_STATIC

static final int STO_STATIC

Static storage class, the storage class that corresponds to static Vars.

See Also:

Constant Field Values

STO_HEAP

static final int STO_HEAP

Heap storage class, the storage class that corresponds to areas allocated by the current subprogram.

See Also:

Constant Field Values

STO_OTHER

static final int STO_OTHER

Other storage class, the storage class that does not fall into current frame or static or heap. It covers automatic Vars from subprograms calling the current subprogram, global Vars that do not appear in the current subprogram, and areas allocated by the subprograms calling the current subprogram.

See Also:

Constant Field Values

fTagVect

TagVector fTagVect

TagVector object that represents all the objects this Tag may represnt. This will change as the analysis goes on.

ANCHORED

static final int ANCHORED

Flag number for anchoredness. See getFlag See setFlag

See Also:

Constant Field Values

HAS_UNION_ANCESTOR

static final int HAS_UNION_ANCESTOR

Flag number for whether being a union descendant. See getFlag See setFlag

See Also:

Constant Field Values

Constructor Detail

Tag

Tag(MyExpId pMyExpId,
    boolean pIsAnchored,
    int pKind,
    int pStorageClass)

Creates a new instance of Tag that is associated with a MyExpId object.

Parameters:

pMyExpId - MyExpId object this Tag is associated with.

pIsAnchored - Is this Tag associated with a single named Var?

pKind - kind of this Tag.

pStorageClass - storage class of this Tag.

Tag

Tag(HIR pmallocInvocationNode)

Creates a new instance of Tag that is associated with an area allocated by a single malloc invocation. malloc invocation within loops are not considered distinct (there are considered a single invocation).

Parameters:

pmallocInvocationNode - FunctionExp node that is an malloc invocation node.

Tag

Tag(int pKind)

Creates a new instance of Tag that corresponds to the STO_OTHER storage class.

Parameters:

pKind - the kind of Tag to be created.

Method Detail

inheritAttributes

void inheritAttributes()

Inherits attributes from the parent Tag. Attributes to be inherited are anchoredness (specified by isAnchored) and HAS_UNION_ANCESTOR flag. Additionally, if this Tag is of kind UNION, sets the HAS_UNION_ANCESTOR flag. See #isAnchored See HAS_UNION_ANCESTOR See KIND_UNION

isAnchored

boolean isAnchored()

Returns true if this Tag has a corresponding anchor. A Tag represents an area in memory, but which area it represents may not be accurately determined at compile time. Tags which are anchored can only represent areas in memory that are inside the area the anchor Tag represents.

Returns:

true if this Tag has a corresponding anchor.

promote

Tag promote()

Returns the Tag that covers the area that the result of the pointer operation that has a pointer expression that points to one of the areas that this Tag represents as one of its operands can point to. It is either fAnchor or this Tag itself.

Returns:

the Tag the area which it represents the result of the pointer operations involving pointers to the area this Tag represents may point to.

getFlag

boolean getFlag(int pFlag)

setFlag

void setFlag(int pFlag,
             boolean pYesNo)

toString

public java.lang.String toString()

Returns the String representation of this Tag.

Returns:

the String representation of this Tag.