mirror of
https://github.com/esphome/esphome.git
synced 2026-07-10 08:55:36 +00:00
J. Nick Koston
6b67224286
Generated setup() is a single monolithic function whose stack frame scales super-linearly with config size. On a 5,943-line apollo build the frame reached 1,264 B at -Os; extrapolation onto larger configs (e.g. the 16k-line LVGL config in #15796) plausibly overflows the 8 KB loop task stack before safe_mode can increment its boot counter. Emit a ComponentMarker sentinel at the start of each component's to_code output, then have cpp_main_section wrap each component's block (and sub-splits of up to 50 statements within each block) in a noinline IIFE lambda. Each lambda's ENTRY frame is released on return, bounding peak stack to setup() frame + max chunk frame. Measured on apollo-r-pro-1-eth (esp32-s3, -Os): setup() frame 1264 B -> 160 B max chunk frame n/a -> 144 B peak setup stack 1264 B -> 304 B (-76%) total flash 792,471 B -> 791,995 B (-476 B) The brace-depth guard in _wrap_in_noinline_iifes ensures we never split between the RawStatement("{") / RawStatement("}") pair emitted by cg.with_local_variable() (currently only wifi), so scoped locals stay intact.
