loki.analyse.abstract_dfa

Functions

dfa_attached(module_or_routine, dfa)

Create a context in which information about defined, live and used symbols is attached to each IR node.

Classes

AbstractDataflowAnalysis()

Base interface for dataflow analyses attaching metadata to IR nodes.
class AbstractDataflowAnalysis

Bases: ABC

Base interface for dataflow analyses attaching metadata to IR nodes.

This abstract class defines the common entry points for providing “Attacher” and “Detacher” Transformation objects that populate the implicit sets of symbols attached to each IR node when the analysis has been performed.

For more info, see the dfa_attached context.

get_attacher() → Any

Returns an instance of the associated “Attacher” Transformation.

get_detacher() → Any

Returns an instance of the associated “Detacher” Transformation.

abstract attach_dataflow_analysis(module_or_routine)
abstract detach_dataflow_analysis(module_or_routine)
dfa_attached(module_or_routine, dfa)

Create a context in which information about defined, live and used symbols is attached to each IR node.

This makes for each IR node the following properties available:

  • Node.live_symbols: symbols defined before the node;

  • Node.defines_symbols: symbols (potentially) defined by the node;

  • Node.uses_symbols: symbols used by the node that had to be defined before.

This is an in-place update of nodes and thus existing references to IR nodes remain valid. When leaving the context the information is removed from IR nodes, while existing references remain valid.

The default analysis, which uses a simplified Reaching Definitions Analysis (see DataflowAnalysis) is used, unless a more specialised implementation is provided via the dfa argument.

Parameters:

  • module_or_routine (Module or Subroutine) – The object for which the IR is to be annotated.

  • dfa (AbstractDataflowAnalysis, optional) – Instance of a dataflow analysis object providing “attacher” and “detacher” mechanisms.