1.0.5.14: make PURIFY a no-op on gencgc

[sbcl.git] / src / runtime / gc-common.c

diff --git a/src/runtime/gc-common.c b/src/runtime/gc-common.c
index 543c20f..11b3add 100644 (file)
--- a/src/runtime/gc-common.c
+++ b/src/runtime/gc-common.c
@@ -367,6 +367,7 @@ scav_code_header(lispobj *where, lispobj object)
         scavenge(&function_ptr->name, 1);
         scavenge(&function_ptr->arglist, 1);
         scavenge(&function_ptr->type, 1);
+        scavenge(&function_ptr->xrefs, 1);
     }
 
     return n_words;
@@ -2434,3 +2435,60 @@ gc_search_space(lispobj *start, size_t words, lispobj *pointer)
     }
     return (NULL);
 }
+
+boolean
+maybe_gc(os_context_t *context)
+{
+#ifndef LISP_FEATURE_WIN32
+    struct thread *thread = arch_os_get_current_thread();
+#endif
+
+    fake_foreign_function_call(context);
+    /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
+     * which case we will be running with no gc trigger barrier
+     * thing for a while.  But it shouldn't be long until the end
+     * of WITHOUT-GCING.
+     *
+     * FIXME: It would be good to protect the end of dynamic space for
+     * CheneyGC and signal a storage condition from there.
+     */
+
+    /* Restore the signal mask from the interrupted context before
+     * calling into Lisp if interrupts are enabled. Why not always?
+     *
+     * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
+     * interrupt hits while in SUB-GC, it is deferred and the
+     * os_context_sigmask of that interrupt is set to block further
+     * deferrable interrupts (until the first one is
+     * handled). Unfortunately, that context refers to this place and
+     * when we return from here the signals will not be blocked.
+     *
+     * A kludgy alternative is to propagate the sigmask change to the
+     * outer context.
+     */
+#ifndef LISP_FEATURE_WIN32
+    if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL) {
+        sigset_t *context_sigmask = os_context_sigmask_addr(context);
+#ifdef LISP_FEATURE_SB_THREAD
+        /* What if the context we'd like to restore has GC signals
+         * blocked? Just skip the GC: we can't set GC_PENDING, because
+         * that would block the next attempt, and we don't know when
+         * we'd next check for it -- and it's hard to be sure that
+         * unblocking would be safe. */
+        if (sigismember(context_sigmask,SIG_STOP_FOR_GC)) {
+            undo_fake_foreign_function_call(context);
+            return 1;
+        }
+#endif
+        thread_sigmask(SIG_SETMASK, context_sigmask, 0);
+    }
+    else
+        unblock_gc_signals();
+#endif
+    /* SIG_STOP_FOR_GC needs to be enabled before we can call lisp:
+     * otherwise two threads racing here may deadlock: the other will
+     * wait on the GC lock, and the other cannot stop the first one... */
+    funcall0(SymbolFunction(SUB_GC));
+    undo_fake_foreign_function_call(context);
+    return 1;
+}