deadcode-graph.sh

Overview

deadcode-graph.sh — find functions nothing calls, using the documate code graph. Why this exists rather than -Wl,--print-gc-sections: that flag lists what the linker THREW AWAY, which by definition is not in flash. The dead code worth finding is what survives gc-sections because something references it without ever calling it -- a function in an ops table, a callback registered into a struct nobody dispatches. deps/dw3000's interface_rx_enable was exactly that: present in the shipped ELF, zero callers, kept because a dwt_mcps_ops table names it. No linker flag can see that; a call graph can. Three tiers, because "the graph shows no callers" is not evidence of death: A zero inbound CALLS, referenced nowhere else in the tree, AND absent from the unindexed upstream. The only tier worth calling a candidate. B zero inbound CALLS, but referenced somewhere in-tree -- an ops table, a SYS_INIT/SHELL_CMD registration, a header declaration. Zephyr registers through linker arrays constantly, so most of tier B is alive. This is NOT a delete list; it is where table-registered dead code hides, and reading the reference is the only way to tell which. U zero inbound CALLS in-tree, but the fetched upstream calls it. Live API. Tier U exists because the first version of this script did not have it and proposed deleting nine woz_aliro_stack methods -- the module reimplements the Nordic Aliro API, and every one of them is called from workspace/ncs-door-lock-and-access-control, which documate does not index. CLAUDE.md warns about exactly this: fetched upstream is not in the graph. Without a workspace to check, tier A is unverifiable and says so. Needs .documate/graph.db, which make docs builds and .gitignore excludes.