Distinguish between GC disabled by BIFs and other disabled GC

Processes remember heap fragments that are known to be fully
live due to creation in a just called BIF that yields in the
live_hf_end field. This field must not be used if we have not
disabled GC in a BIF. F_DELAY_GC has been introduced in order
to distinguish between to two different scenarios.

- F_DISABLE_GC should *only* be used by BIFs. This when
  the BIF needs to yield while preventig a GC.
- F_DELAY_GC should only be used when GC is temporarily
  disabled while the process is scheduled. A process must
  not be scheduled out while F_DELAY_GC is set.

1 files changed, 2 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index ebe9361b8d..d17355207b 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -9262,6 +9262,8 @@ Process *schedule(Process *p, int calls)
     } else {
     sched_out_proc:
 
+	ASSERT(!(p->flags & F_DELAY_GC));
+
 #ifdef ERTS_SMP
 	ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p);
 	esdp = p->scheduler_data;