Merge pull request #15 from glandium/rust

Fix for rust-lang/rust#34674

Author: alexcrichton

src/zone.c

@@ -168,6 +168,33 @@ zone_force_unlock(malloc_zone_t *zone)
 		jemalloc_postfork_parent();
 }
 
+static malloc_zone_t *get_default_zone()
+{
+	malloc_zone_t **zones = NULL;
+	unsigned int num_zones = 0;
+
+	/*
+	 * On OSX 10.12, malloc_default_zone returns a special zone that is not
+	 * present in the list of registered zones. That zone uses a "lite zone"
+	 * if one is present (apparently enabled when malloc stack logging is
+	 * enabled), or the first registered zone otherwise. In practice this
+	 * means unless malloc stack logging is enabled, the first registered
+	 * zone is the default.
+	 * So get the list of zones to get the first one, instead of relying on
+	 * malloc_default_zone.
+	 */
+        if (KERN_SUCCESS != malloc_get_all_zones(0, NULL, (vm_address_t**) &zones,
+	                                         &num_zones)) {
+		/* Reset the value in case the failure happened after it was set. */
+		num_zones = 0;
+	}
+
+	if (num_zones)
+		return zones[0];
+
+	return malloc_default_zone();
+}
+
 JEMALLOC_ATTR(constructor)
 void
 register_zone(void)
@@ -177,7 +204,7 @@ register_zone(void)
 	 * If something else replaced the system default zone allocator, don't
 	 * register jemalloc's.
 	 */
-	malloc_zone_t *default_zone = malloc_default_zone();
+	malloc_zone_t *default_zone = get_default_zone();
 	malloc_zone_t *purgeable_zone = NULL;
 	if (!default_zone->zone_name ||
 	    strcmp(default_zone->zone_name, "DefaultMallocZone") != 0) {
@@ -246,7 +273,6 @@ register_zone(void)
 	malloc_zone_register(&zone);
 
 	do {
-		default_zone = malloc_default_zone();
 		/*
 		 * Unregister and reregister the default zone.  On OSX >= 10.6,
 		 * unregistering takes the last registered zone and places it
@@ -272,5 +298,7 @@ register_zone(void)
 			malloc_zone_unregister(purgeable_zone);
 			malloc_zone_register(purgeable_zone);
 		}
-	} while (malloc_default_zone() != &zone);
+
+		default_zone = get_default_zone();
+	} while (default_zone != &zone);
 }