heros

Interface FlowFunctions<N,D,M>

Type Parameters:

N - The type of nodes in the interprocedural control-flow graph. Typically Unit.

D - The type of data-flow facts to be computed by the tabulation problem.

M - The type of objects used to represent methods. Typically SootMethod.

All Known Implementing Classes:

FlowFunctionCache, ProfiledFlowFunctions, ZeroedFlowFunctions

public interface FlowFunctions<N,D,M>

Classes implementing this interface provide a factory for a range of flow functions used to compute which D-type values are reachable along the program's control flow.

Method Summary

Modifier and Type	Method and Description
FlowFunction<D>	getCallFlowFunction(N callStmt, M destinationMethod) Returns the flow function that computes the flow for a call statement.
FlowFunction<D>	getCallToReturnFlowFunction(N callSite, N returnSite) Returns the flow function that computes the flow from a call site to a successor statement just after the call.
FlowFunction<D>	getNormalFlowFunction(N curr, N succ) Returns the flow function that computes the flow for a normal statement, i.e., a statement that is neither a call nor an exit statement.
FlowFunction<D>	getReturnFlowFunction(N callSite, M calleeMethod, N exitStmt, N returnSite) Returns the flow function that computes the flow for a an exit from a method.

Method Detail

getNormalFlowFunction

FlowFunction<D> getNormalFlowFunction(N curr,
                                      N succ)

Returns the flow function that computes the flow for a normal statement, i.e., a statement that is neither a call nor an exit statement.

Parameters:

curr - The current statement.

succ - The successor for which the flow is computed. This value can be used to compute a branched analysis that propagates different values depending on where control0flow branches.

getCallFlowFunction

FlowFunction<D> getCallFlowFunction(N callStmt,
                                    M destinationMethod)

Returns the flow function that computes the flow for a call statement.

Parameters:

callStmt - The statement containing the invoke expression giving rise to this call.

destinationMethod - The concrete target method for which the flow is computed.

getReturnFlowFunction

FlowFunction<D> getReturnFlowFunction(N callSite,
                                      M calleeMethod,
                                      N exitStmt,
                                      N returnSite)

Returns the flow function that computes the flow for a an exit from a method. An exit can be a return or an exceptional exit.

Parameters:

callSite - One of all the call sites in the program that called the method from which the exitStmt is actually returning. This information can be exploited to compute a value that depends on information from before the call. Note: This value might be null if using a tabulation problem with SolverConfiguration.followReturnsPastSeeds() returning true in a situation where the call graph does not contain a caller for the method that is returned from.

calleeMethod - The method from which exitStmt returns.

exitStmt - The statement exiting the method, typically a return or throw statement.

returnSite - One of the successor statements of the callSite. There may be multiple successors in case of possible exceptional flow. This method will be called for each such successor. Note: This value might be null if using a tabulation problem with SolverConfiguration.followReturnsPastSeeds() returning true in a situation where the call graph does not contain a caller for the method that is returned from.

Returns:

getCallToReturnFlowFunction

FlowFunction<D> getCallToReturnFlowFunction(N callSite,
                                            N returnSite)

Returns the flow function that computes the flow from a call site to a successor statement just after the call. There may be multiple successors in case of exceptional control flow. In this case this method will be called for every such successor. Typically, one will propagate into a method call, using getCallFlowFunction(Object, Object), only such information that actually concerns the callee method. All other information, e.g. information that cannot be modified by the call, is passed along this call-return edge.

Parameters:

callSite - The statement containing the invoke expression giving rise to this call.

returnSite - The return site to which the information is propagated. For exceptional flow, this may actually be the start of an exception handler.