update ffi wrapper

src/ffi.rs

@@ -14,8 +14,10 @@ extern "C" {
 /// * `data` can be `null`, it is passed as the 2nd argument to `cb` as-is.
 /// * The first argument to `cb` is guaranteed to be a non-aliased, properly aligned, and non-null pointer with `size` read+writable memory. If `size` is 0, it may dangle.
 /// * `cb` is guaranteed to be called unless allocating `size` bytes on the stack causes a stack overflow, in which case the program will terminate.
-/// * The data pointed to by `ptr` is guaranteed to be popped from the stack once `cb` returns (even in the case of a `longjmp`, but `panic!()` within the callback is still undefined behaviour).
+/// * The data pointed to by `ptr` is guaranteed to be popped from the stack once this function returns (even in the case of a `longjmp`, but `panic!()` within the callback is still undefined behaviour).
-#[inline(always)] pub unsafe fn alloca_trampoline(size: usize, cb: CallbackRaw, data: *mut c_void)
+// Never inline this, in case LTO inlines the call to `_alloca_trampoline`, we always want this function to pop the alloca'd memory.
+// (NOTE: Test to see if this can ever happen. If it can't, the change this to `inline(always)` or remove the `inline` attribute
+#[inline(never)] pub unsafe fn alloca_trampoline(size: usize, cb: CallbackRaw, data: *mut c_void)
 {
     _alloca_trampoline(size, Some(cb), data);
 }