From 3f5487ca902fb07fe8e334633a2fddfd6cf18762 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Wed, 13 May 2020 15:57:17 +0200
Subject: [PATCH] [python] Forbid inlining on gc_collect to avoid missing some
 roots

---
 python/port/port.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/python/port/port.cpp b/python/port/port.cpp
index be16aece9..385367101 100644
--- a/python/port/port.cpp
+++ b/python/port/port.cpp
@@ -248,7 +248,10 @@ KDColor MicroPython::ColorParser::ParseColor(mp_obj_t input, ColorMode ColorMode
   mp_raise_TypeError("Color couldn't be parsed");
 }
 
-void gc_collect(void) {
+/* Forbid inlining to ensure regs to be at the top of the stack. Otherwise,
+ * LTO inlining can make regs lower on the stack than some just-allocated
+ * pointers. */
+__attribute__((noinline)) void gc_collect(void) {
   void * python_stack_top = MP_STATE_THREAD(stack_top);
   assert(python_stack_top != NULL);