Dwgrep is a tool, an associated language (called Zwerg) and a library
(libzwerg) for querying Dwarf (debuginfo) graphs.
You can think of dwgrep expressions as instructions describing a path
through a graph, with assertions about the type of nodes along the
way: that a node is of given type, that it has a given attribute,
etc. There are also means of expressing sub-conditions,
i.e. assertions that a given node is acceptable if a separate
expression matches (or does not match) a different path through the
graph.
