update mac zone code

1 files changed, 67 insertions, 0 deletions

diff --git a/src/alloc-override-osx.c b/src/alloc-override-osx.c
index ed0bc2d..99c6a13 100644
--- a/src/alloc-override-osx.c
+++ b/src/alloc-override-osx.c
@@ -182,6 +182,72 @@ static malloc_zone_t* mi_get_default_zone()
   }
 }
 
+// directly overwrite the default zone as per:
+// <https://lists.apple.com/archives/darwin-dev/2005/Apr/msg00050.html>
+
+static void __attribute__((constructor)) _mi_macos_override_malloc_direct()
+{
+  static malloc_introspection_t intro;
+  memset(&intro, 0, sizeof(intro));
+
+  intro.enumerator = &intro_enumerator;
+  intro.good_size = &intro_good_size;
+  intro.check = &intro_check;
+  intro.print = &intro_print;
+  intro.log = &intro_log;
+  intro.force_lock = &intro_force_lock;
+  intro.force_unlock = &intro_force_unlock;
+
+  static malloc_zone_t oldzone;
+  static malloc_zone_t* zone = malloc_default_zone(); // get the `malloc` backing default zone
+  if (zone == NULL) return;
+
+  // save the default zone in oldzone
+  memset(&oldzone, 0, sizeof(oldzone));
+  if (zone->version >= 9) memcpy(&oldzone, zone, sizeof(oldzone));
+
+  // overwrite default zone functions in-place
+  zone->zone_name = "mimalloc";
+  zone->size = &zone_size;
+  zone->introspect = &intro;
+  zone->malloc = &zone_malloc;
+  zone->calloc = &zone_calloc;
+  zone->valloc = &zone_valloc;
+  zone->free = &zone_free;
+  zone->realloc = &zone_realloc;
+  zone->destroy = &zone_destroy;
+  zone->batch_malloc = &zone_batch_malloc;
+  zone->batch_free = &zone_batch_free;
+
+  malloc_zone_t* purgeable_zone = NULL;
+
+#if defined(MAC_OS_X_VERSION_10_6) && \
+    MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
+  // switch to version 9 on OSX 10.6 to support memalign.
+  // zone->version = 9;
+  zone->memalign = &zone_memalign;
+  zone->free_definite_size = &zone_free_definite_size;
+  zone->pressure_relief = &zone_pressure_relief;
+  intro.zone_locked = &intro_zone_locked;
+  intro.statistics = &intro_statistics;
+  /*
+  // force the purgeable zone to exist to avoid strange bugs
+  if (malloc_default_purgeable_zone) {
+    purgeable_zone = malloc_default_purgeable_zone();
+  }
+  */
+#endif
+  /*
+  // Unregister, and re-register the purgeable_zone to avoid bugs if it occurs
+  // earlier than the default zone.
+  if (purgeable_zone != NULL) {
+    malloc_zone_unregister(purgeable_zone);
+    malloc_zone_register(purgeable_zone);
+  }
+  */
+}
+
+/*
 static void __attribute__((constructor)) _mi_macos_override_malloc()
 {
   static malloc_introspection_t intro;
@@ -248,5 +314,6 @@ static void __attribute__((constructor)) _mi_macos_override_malloc()
   }
 
 }
+*/
 
 #endif // MI_MALLOC_OVERRIDE