Fix nRF52 loop stack allocation under LTO

scripts/nrf52_loop_stack_fix.py

@@ -0,0 +1,56 @@
+"""Make the nRF52 core's loop task use the configured stack even under LTO.
+
+GNU --wrap only redirects undefined references. The pinned core and FreeRTOS
+share an LTO graph, so its xTaskCreate call can bind directly to the real
+function and silently retain the framework's 4 KiB stack. Explicitly route
+only the core loop-task call through MeshCore's existing stack policy in a
+private build copy. Never edit the shared framework package.
+"""
+
+from pathlib import Path
+
+
+OLD_LOOP_CREATE = '  xTaskCreate(loop_task, "loop", LOOP_STACK_SZ, NULL, TASK_PRIO_LOW, &_loopHandle);'
+LOOP_CREATE = OLD_LOOP_CREATE.replace("xTaskCreate(", "__wrap_xTaskCreate(", 1)
+DECLARATION = """extern "C" BaseType_t __wrap_xTaskCreate(
+    TaskFunction_t task_code, const char* const task_name,
+    const configSTACK_DEPTH_TYPE stack_depth, void* const parameters,
+    UBaseType_t priority, TaskHandle_t* const created_task);
+
+"""
+LOOP_STACK = "#define LOOP_STACK_SZ       (256*4)"
+
+
+def patched_source(source):
+    source = source.replace("\r\n", "\n")
+    if (source.count(LOOP_CREATE) == 1 and source.count(DECLARATION) == 1
+            and OLD_LOOP_CREATE not in source and source.count(LOOP_STACK) == 1):
+        return source
+    if (source.count(OLD_LOOP_CREATE) != 1 or source.count(LOOP_STACK) != 1
+            or LOOP_CREATE in source or DECLARATION in source):
+        raise RuntimeError(
+            "nRF52 loop stack fix: unrecognized core task creation; review the "
+            "framework update before building (shared SDK not modified)"
+        )
+    return source.replace(LOOP_STACK, DECLARATION + LOOP_STACK).replace(
+        OLD_LOOP_CREATE, LOOP_CREATE)
+
+
+def replace_core(build_env, node):
+    source = Path(node.srcnode().get_abspath())
+    patched = patched_source(source.read_text(encoding="utf-8"))
+    destination = Path(build_env.subst("$BUILD_DIR")) / "patched-nrf52-core" / "main.cpp"
+    destination.parent.mkdir(parents=True, exist_ok=True)
+    if not destination.exists() or destination.read_text(encoding="utf-8") != patched:
+        destination.write_text(patched, encoding="utf-8")
+    print("nRF52 loop stack: explicit LTO-safe core task policy enabled")
+    return build_env.File(str(destination))
+
+
+def install(build_env):
+    build_env.AddBuildMiddleware(replace_core, "*cores*nRF5*main.cpp")
+
+
+if "Import" in globals():
+    Import("env")
+    install(env)