This parameterizes the GC a bit to make it thread-ready.

The basic idea is that whenever a thread "exits lisp" -- that is,
releases the global lock in favor of another thread -- it must save
its stack boundaries in the thread object.  This way the boundaries
are always available for marking.  This is the purpose of
flush_stack_call_func.

I haven't tested this under all the possible GC configurations.
There is a new FIXME in a spot that i didn't convert.

Arguably all_threads should go in the previous patch.

1 files changed, 79 insertions, 0 deletions

diff --git a/src/thread.c b/src/thread.c
index 0bd97b4fd8e..ba2d66320fa 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -24,3 +24,82 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 struct thread_state the_only_thread;
 
 struct thread_state *current_thread = &the_only_thread;
+
+struct thread_state *all_threads = &the_only_thread;
+
+static void
+mark_one_thread (struct thread_state *thread)
+{
+  register struct specbinding *bind;
+  struct handler *handler;
+  Lisp_Object tem;
+
+  for (bind = thread->m_specpdl; bind != thread->m_specpdl_ptr; bind++)
+    {
+      mark_object (bind->symbol);
+      mark_object (bind->old_value);
+    }
+
+#if (GC_MARK_STACK == GC_MAKE_GCPROS_NOOPS \
+     || GC_MARK_STACK == GC_MARK_STACK_CHECK_GCPROS)
+  mark_stack (thread->m_stack_bottom, thread->stack_top);
+#else
+  {
+    register struct gcpro *tail;
+    for (tail = thread->m_gcprolist; tail; tail = tail->next)
+      for (i = 0; i < tail->nvars; i++)
+        mark_object (tail->var[i]);
+  }
+
+#if BYTE_MARK_STACK
+  if (thread->m_byte_stack_list)
+    mark_byte_stack (thread->m_byte_stack_list);
+#endif
+
+  mark_catchlist (thread->m_catchlist);
+
+  for (handler = thread->m_handlerlist; handler; handler = handler->next)
+    {
+      mark_object (handler->handler);
+      mark_object (handler->var);
+    }
+
+  mark_backtrace (thread->m_backtrace_list);
+#endif
+
+  if (thread->m_current_buffer)
+    {
+      XSETBUFFER (tem, thread->m_current_buffer);
+      mark_object (tem);
+    }
+
+  mark_object (thread->m_last_thing_searched);
+
+  if (thread->m_saved_last_thing_searched)
+    mark_object (thread->m_saved_last_thing_searched);
+}
+
+static void
+mark_threads_callback (void *ignore)
+{
+  struct thread_state *iter;
+
+  for (iter = all_threads; iter; iter = iter->next_thread)
+    mark_one_thread (iter);
+}
+
+void
+mark_threads (void)
+{
+  flush_stack_call_func (mark_threads_callback, NULL);
+}
+
+void
+unmark_threads (void)
+{
+  struct thread_state *iter;
+
+  for (iter = all_threads; iter; iter = iter->next_thread)
+    if (iter->m_byte_stack_list)
+      unmark_byte_stack (iter->m_byte_stack_list);
+}