DFA4

Cache basic def/use information at the instruction level

CACHE_DUI + cache standard ud-chains and du-chains

Nothing is cached

Create a DFA object with CFG-provided default collection flags and basic caching for instruction-level def-use information. This object can be further configured by invoking its various setters.

Create a DFA object. This object can be further configured by invoking its various setters.

Check whether a variable, defined at the provided instruction, is not used.

Check whether a variable, defined at the provided instruction, is not used.

Check whether a variable, defined at the provided instruction, is not used.

Check whether a used variable has a single definition point. The def point may be explicit (e.g. resulting from an assignment) or implicit (e.g. provided as a parameter to the routine, which is always represented as the address -1).

Check whether a used variable has a single explicit definition point (i.e. it is a non-input defined at a unique address).

Check whether a used variable has a single explicit definition point. The def point cannot be a routine input (i.e. the definition must be explicit).

Retrieve the cache configuration.

Retrieve a reference to the CFG object that will be accessed and modified when performing an analysis.

Find the list of usage points for a defined variable.

Retrieve the maximum block count used for common DFA operations. See setMaxBlocks(int) for details.

Find the list of definition points for a used variable.

Retrieve the list of use-discrepancies at the provided instruction address.

Retrieve the variable collection flags.

Invalidate the analysis. Clients have the responsibility to invalidate an analysis if the CFG was modified in such a way that data flow should be recalculated.

Determine if a variable reaching a start instruction has not been redefined when it reaches a final instruction. (Note that this method does not verify that varid actually has definitions reaching the start or final instruction; it is up to the caller to verify that.)

Determine if a variable reaching a start instruction has not been redefined when it reaches a final instruction. (Note that this method does not verify that varid actually has definitions reaching the start or final instruction; it is up to the caller to verify that.)

Determine whether the provided block is a terminator. A terminator has no output and its final instruction is a clean routine terminator.

Determine whether the current analysis was performed and is valid.

Determine if a variable used by the start instruction reaches the final instruction with the same value. This method provides a must-reach result: if a multiple paths exist from start to end, where the variable reaches the end via some paths, but not on others (it is overwritten), the method returns false.

Determine if a variable used by the start instruction reaches the final instruction with the same value.

Important notes:
- This method provides a must-reach result: if a multiple paths exist from start to end, where the variable reaches the end via some paths, but not on others (it is overwritten), the method returns false.
- This method works from the start point to an end point, and provides the guarantee that the variable was not overwritten when it reached the end-point. There is no guarantee provided at the end-point itself.

Perform data flow analysis on the CFG. Upon return, basic blocks will have their data chains (ud and du, full and simple) set up and accessible.

Set or update the cache configuration of this object.

Set an exploration threshold for most DFA operations. By default, there is no threshold. The threshold is a block count; if a block count is reached, a chain may contain a reference to the invalid address -2 in order to indicate an incomplete result.

Set the variable collection flags.