The compilers, linkers, debuggers, libraries and build utilities, at fixed versions and configurations, that are supported for building software for the chip.
Source Work product in the Firmware and software stack lifecycle
It makes builds consistent and reproducible for the supplier and customers. The same code compiled with different compilers can behave differently, producing defects nobody can reproduce, and safety-related products then lack tool qualification evidence.
The full lifecycle detail, with its charts, flows, tables and every section, is for registered members. Registration is free and takes a minute. You come back to this page afterwards.