From 92741bb2c9ff09bce7ff8b6c7c7788acc1de331e Mon Sep 17 00:00:00 2001
From: Ivan Maidanski <ivmai@mail.ru>
Date: Sat, 28 Jul 2018 00:29:59 +0300
Subject: [PATCH] Export stop/start_world_external only for multi-threaded
 builds (fix of commit bb91f03)

Issue #173 (bdwgc).

Also, update GC_world_stopped value in GC_stop_world_external and
GC_start_world_external.

* include/gc.h (GC_stop_world_external, GC_start_world_external): Do not
declare unless GC_THREADS; add comment.
* misc.c (GC_stop_world_external, GC_start_world_external): Do not
define unless THREADS; add assertion that GC is initialized.
* misc.c [THREADS && THREAD_LOCAL_ALLOC] (GC_stop_world_external): Set
GC_world_stopped to true after STOP_WORLD; add assertion that the
world is not stopped.
* misc.c [THREADS && THREAD_LOCAL_ALLOC] (GC_start_world_external): Set
GC_world_stopped to false before START_WORLD; add assertion that the
world is stopped.
* tests/test.c [GC_PTHREADS && CPPCHECK] (main): Add UNTESTED for
GC_stop_world_external and GC_start_world_external.
---
 include/gc.h |  7 ++++---
 misc.c       | 27 +++++++++++++++++++++------
 tests/test.c |  2 ++
 3 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/include/gc.h b/include/gc.h
index 0a4ee50..b8b0692 100644
--- a/include/gc.h
+++ b/include/gc.h
@@ -1503,6 +1503,10 @@ GC_API void * GC_CALL GC_call_with_stack_base(GC_stack_base_func /* fn */,
   /* be called inside a GC callback function (except for                */
   /* GC_call_with_stack_base() one).                                    */
   GC_API int GC_CALL GC_unregister_my_thread(void);
+
+  /* Stop/start the world explicitly.  Not recommended for general use. */
+  GC_API void GC_CALL GC_stop_world_external(void);
+  GC_API void GC_CALL GC_start_world_external(void);
 #endif /* GC_THREADS */
 
 /* Wrapper for functions that are likely to block (or, at least, do not */
@@ -2042,9 +2046,6 @@ GC_API void GC_CALL GC_win32_free_heap(void);
         (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_ignore_off_page)
 #endif /* _AMIGA && !GC_AMIGA_MAKINGLIB */
 
-GC_API void GC_CALL GC_stop_world_external(void);
-GC_API void GC_CALL GC_start_world_external(void);
-
 #ifdef __cplusplus
   } /* extern "C" */
 #endif
diff --git a/misc.c b/misc.c
index a597a0a..6bfa4a1 100644
--- a/misc.c
+++ b/misc.c
@@ -2529,14 +2529,29 @@ GC_API void GC_CALL GC_abort_on_oom(void)
     EXIT();
 }
 
-GC_API void GC_CALL GC_stop_world_external(void)
-{
+#ifdef THREADS
+  GC_API void GC_CALL GC_stop_world_external(void)
+  {
+    GC_ASSERT(GC_is_initialized);
     LOCK();
+#   ifdef THREAD_LOCAL_ALLOC
+      GC_ASSERT(!GC_world_stopped);
+#   endif
     STOP_WORLD();
-}
+#   ifdef THREAD_LOCAL_ALLOC
+      GC_world_stopped = TRUE;
+#   endif
+  }
 
-GC_API void GC_CALL GC_start_world_external(void)
-{
+  GC_API void GC_CALL GC_start_world_external(void)
+  {
+#   ifdef THREAD_LOCAL_ALLOC
+      GC_ASSERT(GC_world_stopped);
+      GC_world_stopped = FALSE;
+#   else
+      GC_ASSERT(GC_is_initialized);
+#   endif
     START_WORLD();
     UNLOCK();
-}
+  }
+#endif /* THREADS */
diff --git a/tests/test.c b/tests/test.c
index efce7f4..17f61d3 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -2340,6 +2340,8 @@ int main(void)
       UNTESTED(GC_set_on_thread_event);
       UNTESTED(GC_set_suspend_signal);
       UNTESTED(GC_set_thr_restart_signal);
+      UNTESTED(GC_stop_world_external);
+      UNTESTED(GC_start_world_external);
 #     ifndef GC_NO_DLOPEN
         UNTESTED(GC_dlopen);
 #     endif
-- 
2.7.4