+ check_gc_signals_unblocked_in_sigset_or_lose
+ (os_context_sigmask_addr(context));
+ unblock_gc_signals();
+#endif
+ FSHOW((stderr, "/maybe_gc: calling SUB_GC\n"));
+ /* FIXME: Nothing must go wrong during GC else we end up running
+ * the debugger, error handlers, and user code in general in a
+ * potentially unsafe place. Running out of the control stack or
+ * the heap in SUB-GC are ways to lose. Of course, deferrables
+ * cannot be unblocked because there may be a pending handler, or
+ * we may even be in a WITHOUT-INTERRUPTS. */
+ gc_happened = funcall0(StaticSymbolFunction(SUB_GC));
+ FSHOW((stderr, "/maybe_gc: gc_happened=%s\n",
+ (gc_happened == NIL) ? "NIL" : "T"));
+ if ((gc_happened != NIL) &&
+ /* See if interrupts are enabled or it's possible to enable
+ * them. POST-GC has a similar check, but we don't want to
+ * unlock deferrables in that case and get a pending interrupt
+ * here. */
+ ((SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) ||
+ (SymbolValue(ALLOW_WITH_INTERRUPTS,thread) != NIL))) {
+ sigset_t *context_sigmask = os_context_sigmask_addr(context);
+ if (!deferrables_blocked_in_sigset_p(context_sigmask)) {
+ FSHOW((stderr, "/maybe_gc: calling POST_GC\n"));
+ thread_sigmask(SIG_SETMASK, context_sigmask, 0);
+ check_gc_signals_unblocked_or_lose();
+ funcall0(StaticSymbolFunction(POST_GC));
+ } else {
+ FSHOW((stderr, "/maybe_gc: punting on POST_GC due to blockage\n"));
+ }