cetus.analysis

Class IPPointsToAnalysis

java.lang.Object

cetus.analysis.AnalysisPass

cetus.analysis.IPAnalysis

cetus.analysis.IPPointsToAnalysis

public class IPPointsToAnalysis
extends IPAnalysis

Interprocedural analysis enables computation of points-to relations through whole-program analysis provided by the common interprocedural framework in Cetus. The algorithms are based on "Context-sensitive inter-procedural points-to analysis in the presence of function pointers", PLDI'94. Although handling of function pointers and precise context-sensitivity as in the paper are not supported, the analysis provides single-depth context-sensitivity (differentiates call sites) and supports most features presented in the paper.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IPPointsToAnalysis.AbstractLocation AbstractLocation represents a abstract location that is not referenced to in terms of a program variable.

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.Set<Symbol>	return_vars

Constructor Summary

Constructors

Constructor and Description
IPPointsToAnalysis(Program program) Constructs a new interprocedural points-to analyzer.

Method Summary

Methods

Modifier and Type	Method and Description
void	analyzeProcedure(IPANode node) Invokes intraprocedural analysis.
static void	clearPointsToRelations() Invalidates the analysis result.
static boolean	containsUniverse() Checks if the current points-to analysis result contains points-to-universe relation.
static Domain	getPointsToRelations(Statement stmt) Returns points-to relations for the given statement.
static java.util.Set<PointsToRel>	getReturnRelations(CallSite callsite) Returns the set of points-to relations pointed by the return value of the specified function call.
static boolean	isSafeLibraryCall(FunctionCall fcall) Checks if the given function call is known for having no side effects on the "points-to relation" (not on memory).
void	start() Starts interprocedural points-to analysis.
boolean	updateCall(IPANode node) Not used.
java.util.Set<CallSite>	updateCalls(IPANode node) Updates the forward information for each call site by performing mapping, and by maintaining map-info for each different single-depth context.
static void	updatePointsToRelations(Program program) Recompute the static points-to relations for the given program.
boolean	updateReturn(IPANode node) Updates the backward information available at the exit of a procedure by performing unmapping.

Methods inherited from class cetus.analysis.IPAnalysis

getPassName

Methods inherited from class cetus.analysis.AnalysisPass

run

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

return_vars

public static final java.util.Set<Symbol> return_vars

Constructor Detail

IPPointsToAnalysis

public IPPointsToAnalysis(Program program)

Constructs a new interprocedural points-to analyzer.

Parameters:

program - the input program.

Method Detail

getPointsToRelations

public static Domain getPointsToRelations(Statement stmt)

Returns points-to relations for the given statement. The program is analyzed again if the result is invalid.

Parameters:

stmt - the statement before which points-to relations are computed.

Returns:

the points-to relations map for the procedure.

clearPointsToRelations

public static void clearPointsToRelations()

Invalidates the analysis result. A transformation pass should trigger this operation.

updatePointsToRelations

public static void updatePointsToRelations(Program program)

Recompute the static points-to relations for the given program. The result of the analysis is stored as a static map for future reuse.

Parameters:

program - the program to be analyzed.

start

public void start()

Starts interprocedural points-to analysis.

Overrides:

start in class IPAnalysis

analyzeProcedure

public void analyzeProcedure(IPANode node)

Invokes intraprocedural analysis. The following information is the input to the intra analysis. - IN data after mapping process. - OUT data after each call site.

Parameters:

node - the procedure node to be analyzed.

getReturnRelations

public static java.util.Set<PointsToRel> getReturnRelations(CallSite callsite)

Returns the set of points-to relations pointed by the return value of the specified function call. It uses the normalized return value as the pointer symbol and the caller's symbol as the pointed-to symbol. For a standard library call, the function symbol is used as the pointer symbol.

Parameters:

callsite - the calling site that generates the query.

Returns:

the set of return points-to relations. an empty set means there is no relations created, and null means no information is available (should produce universe doamin).

isSafeLibraryCall

public static boolean isSafeLibraryCall(FunctionCall fcall)

Checks if the given function call is known for having no side effects on the "points-to relation" (not on memory).

Parameters:

fcall - the function call to be examined.

Returns:

true if it is either a standard library call or a known system library call.

updateCalls

public java.util.Set<CallSite> updateCalls(IPANode node)

Updates the forward information for each call site by performing mapping, and by maintaining map-info for each different single-depth context.

Parameters:

node - the procedure node being analyzed.

Returns:

the set of call sites whose data has been changed.

updateCall

public boolean updateCall(IPANode node)

Not used.

Parameters:

node - the node that was just analyzed.

Returns:

true if the IN data of any call site has been updated.

updateReturn

public boolean updateReturn(IPANode node)

Updates the backward information available at the exit of a procedure by performing unmapping.

Parameters:

node - the procedure node to be analyzed.

Returns:

true if there is any state change, false otherwise.

containsUniverse

public static boolean containsUniverse()

Checks if the current points-to analysis result contains points-to-universe relation.