starting on callgraph generation. callgraph.rs:: dump_functions(),.. adding information from local crate into 'CrossCrateMap' so we have one way to get DefId->code location/symbol. (cross_crate_map_combine_current_crate. Did some cleanup of cross_crate_map loading while we did that - added 'cross_crate_map_read_into' which accumulates into a given map instead of returning a single crate as a temporary.