--- libmalloc/libmalloc-474.0.13/src/malloc.c
+++ libmalloc/libmalloc-317.121.1/src/malloc.c
@@ -23,12 +23,12 @@
 
 #include "internal.h"
 
-#if MALLOC_TARGET_IOS
+#if TARGET_OS_IPHONE
 // malloc_report(ASL_LEVEL_INFO...) on iOS doesn't show up in the Xcode Console log of the device,
 // but ASL_LEVEL_NOTICE does.  So raising the log level is helpful.
 #undef ASL_LEVEL_INFO
 #define ASL_LEVEL_INFO ASL_LEVEL_NOTICE
-#endif // MALLOC_TARGET_IOS
+#endif // TARGET_OS_IPHONE
 
 #define USE_SLEEP_RATHER_THAN_ABORT 0
 
@@ -48,33 +48,17 @@
 int32_t malloc_num_zones = 0;
 int32_t malloc_num_zones_allocated = 0;
 malloc_zone_t **malloc_zones = (malloc_zone_t **)0xdeaddeaddeaddead;
-
-// TODO: getter and setter rather than direct export so that this can be baked
-// into the cached fastpath checks
 malloc_logger_t *malloc_logger = NULL;
 
 static uint32_t initial_num_zones;
 static malloc_zone_t *initial_scalable_zone;
-#if CONFIG_NANOZONE
 static malloc_zone_t *initial_nano_zone;
-#endif // CONFIG_NANOZONE
-malloc_zone_t *initial_xzone_zone;
-static malloc_zone_t *default_purgeable_zone;
-static bool has_injected_zone0;
-static bool malloc_xzone_enabled;
+static malloc_zone_t *initial_default_zone = NULL;
 
 unsigned malloc_debug_flags = 0;
 bool malloc_tracing_enabled = false;
 bool malloc_space_efficient_enabled = false;
-bool malloc_medium_space_efficient_enabled = true;
-
-bool malloc_sanitizer_enabled = false;
-
-bool malloc_interposition_compat = false;
-
-#if CONFIG_MALLOC_PROCESS_IDENTITY
-malloc_process_identity_t malloc_process_identity = MALLOC_PROCESS_NONE;
-#endif // CONFIG_MALLOC_PROCESS_IDENTITY
+bool malloc_medium_space_efficient_enabled = false;
 
 unsigned malloc_check_start = 0; // 0 means don't check
 unsigned malloc_check_counter = 0;
@@ -82,40 +66,19 @@
 
 static int malloc_check_sleep = 100; // default 100 second sleep
 static int malloc_check_abort = 0;   // default is to sleep, not abort
-static bool malloc_simple_stack_logging = false;
-#define MALLOC_SIMPLE_STACK_LOGGING_FLAGS \
-		(ASL_LEVEL_NOTICE | MALLOC_REPORT_NOPREFIX | MALLOC_REPORT_BACKTRACE | MALLOC_REPORT_NOWRITE)
-
-static bool malloc_slowpath = false;
-
-static struct _malloc_msl_symbols msl = {};
-
-static struct malloc_sanitizer_poison *sanitizer = NULL;
-
-#if CONFIG_SANITIZER && TARGET_OS_OSX
-// Fallback pointers for memory poisoning functions from upstream ASan runtime
-static struct {
-	void (*memory_poison)(uintptr_t ptr, size_t sz);
-	void (*memory_unpoison)(uintptr_t ptr, size_t sz);
-} sanitizer_fallback_ptrs;
-
-// Fallback structure for heap allocation functions from our ASan runtime
-static struct malloc_sanitizer_poison sanitizer_fallback = {0};
-
-static void malloc_sanitizer_fallback_allocate_poison(uintptr_t ptr, size_t leftrz_sz, size_t alloc_sz, size_t rightrz_sz);
-static void malloc_sanitizer_fallback_deallocate_poison(uintptr_t ptr, size_t sz);
-#endif
-/* These masks are exported for libdispatch to register with (see "internal.h") */
-const unsigned long malloc_memorypressure_mask_default_4libdispatch = MALLOC_MEMORYPRESSURE_MASK_DEFAULT;
-const unsigned long malloc_memorypressure_mask_msl_4libdispatch = MALLOC_MEMORYPRESSURE_MASK_MSL;
-
-// TODO delete this, its only used some deprecated functions like turn_on_stack_logging,
-// which have been replaced by functions in MallocStackLogging.framework
-// (like msl_turn_on_stack_logging)
-static struct msl_dylib {
-	
+
+static
+struct msl {
 	void *dylib;
 
+	void (*handle_memory_event) (unsigned long event);
+	boolean_t (*stack_logging_locked) (void);
+	void (*fork_prepare) (void);
+	void (*fork_parent) (void);
+	void (*fork_child) (void);
+	
+	
+	// TODO delete these ones
 	kern_return_t (*get_frames_for_address)(task_t task,
 											mach_vm_address_t address,
 											mach_vm_address_t *stack_frames_buffer,
@@ -137,9 +100,7 @@
 												mach_vm_address_t *out_frames_buffer,
 												uint32_t *out_frames_count,
 												uint32_t max_frames);
-} msld = {};
-
-MALLOC_NOEXPORT malloc_zone_t* lite_zone = NULL;
+} msl = {};
 
 /*
  * Counters that coordinate zone destruction (in malloc_zone_unregister) with
@@ -159,9 +120,9 @@
 #define MALLOC_LOG_TYPE_CLEARED stack_logging_flag_cleared
 
 #define DEFAULT_MALLOC_ZONE_STRING "DefaultMallocZone"
-#define DEFAULT_SCALABLE_ZONE_STRING "DefaultScalableMallocZone"
 #define DEFAULT_PUREGEABLE_ZONE_STRING "DefaultPurgeableMallocZone"
 #define MALLOC_HELPER_ZONE_STRING "MallocHelperZone"
+#define MALLOC_PGUARD_ZONE_STRING "ProbGuardMallocZone"
 
 MALLOC_NOEXPORT
 unsigned int phys_ncpus;
@@ -169,40 +130,19 @@
 MALLOC_NOEXPORT
 unsigned int logical_ncpus;
 
-#if CONFIG_MAGAZINE_PER_CLUSTER
-MALLOC_NOEXPORT
-unsigned int ncpuclusters;
-#endif // CONFIG_MAGAZINE_PER_CLUSTER
-
 MALLOC_NOEXPORT
 unsigned int hyper_shift;
 
-MALLOC_NOEXPORT
-size_t malloc_absolute_max_size;
-
 // Boot argument for max magazine control
 static const char max_magazines_boot_arg[] = "malloc_max_magazines";
 
 static const char large_expanded_cache_threshold_boot_arg[] = "malloc_large_expanded_cache_threshold";
-
-
-MALLOC_NOEXPORT
-unsigned malloc_zero_on_free_sample_period = 0; // 0 means don't sample
-
-static const char zero_on_free_sample_period_boot_arg[] = "malloc_zero_on_free_sample_period";
-
-MALLOC_NOEXPORT
-malloc_zero_policy_t malloc_zero_policy = MALLOC_ZERO_POLICY_DEFAULT;
-
-static const char zero_on_free_enabled_boot_arg[] = "malloc_zero_on_free_enabled";
-
 
 #if CONFIG_MEDIUM_ALLOCATOR
 static const char medium_enabled_boot_arg[] = "malloc_medium_zone";
 static const char max_medium_magazines_boot_arg[] = "malloc_max_medium_magazines";
 static const char medium_activation_threshold_boot_arg[] = "malloc_medium_activation_threshold";
 static const char medium_space_efficient_boot_arg[] = "malloc_medium_space_efficient";
-static const char medium_madvise_dram_scale_divisor_boot_arg[] = "malloc_medium_madvise_dram_scale_divisor";
 #endif // CONFIG_MEDIUM_ALLOCATOR
 
 /*********	Utilities	************/
@@ -214,29 +154,12 @@
 typedef void * (*dlopen_t) (const char * __path, int __mode);
 typedef void * (*dlsym_t) (void * __handle, const char * __symbol);
 
-static dlopen_t LIBMALLOC_FUNCTION_PTRAUTH(_dlopen) = NULL;
-static dlsym_t LIBMALLOC_FUNCTION_PTRAUTH(_dlsym) = NULL;
+static dlopen_t _dlopen = NULL;
+static dlsym_t _dlsym = NULL;
 #else
 #define _dlopen(...) NULL
 #define _dlsym(...) NULL
 #endif // TARGET_OS_DRIVERKIT
-
-void
-malloc_slowpath_update(void)
-{
-	bool slowpath = has_injected_zone0 ||
-			malloc_num_zones == 0 ||
-			malloc_check_start ||
-			lite_zone ||
-			malloc_tracing_enabled ||
-			malloc_simple_stack_logging ||
-			malloc_interposition_compat;
-
-	if (malloc_slowpath != slowpath) {
-		malloc_slowpath = slowpath;
-	}
-}
-
 
 void __malloc_init(const char *apple[]);
 static void _malloc_initialize(const char *apple[], const char *bootargs);
@@ -279,9 +202,9 @@
 }
 #endif /* TARGET_OS_OSX */
 
+
 #define LIBMALLOC_EXPERIMENT_FACTORS_KEY "MallocExperiment="
 #define LIBMALLOC_EXPERIMENT_DISABLE_MEDIUM (1ULL)
-#define LIBMALLOC_DEFERRED_RECLAIM_ENABLE "MallocDeferredReclaim=1"
 static void
 __malloc_init_experiments(const char *str)
 {
@@ -332,33 +255,6 @@
 		}
 	}
 
-	flag = malloc_common_value_for_key_copy(bootargs,
-			zero_on_free_enabled_boot_arg, value_buf, sizeof(value_buf));
-	if (flag) {
-		const char *endp;
-		long value = malloc_common_convert_to_long(flag, &endp);
-		if (!*endp && (value == 0 || value == 1)) {
-			malloc_zero_policy = value ? MALLOC_ZERO_ON_FREE : MALLOC_ZERO_NONE;
-		} else {
-			malloc_report(ASL_LEVEL_ERR,
-					"malloc_zero_on_free_enabled must be 0 or 1 - ignored.\n");
-		}
-	}
-
-	flag = malloc_common_value_for_key_copy(bootargs,
-			zero_on_free_sample_period_boot_arg, value_buf, sizeof(value_buf));
-	if (flag) {
-		const char *endp;
-		long value = malloc_common_convert_to_long(flag, &endp);
-		if (!*endp && value >= 0) {
-			malloc_zero_on_free_sample_period = (unsigned int)value;
-		} else {
-			malloc_report(ASL_LEVEL_ERR,
-					"malloc_zero_on_free_sample_period must be positive - ignored.\n");
-		}
-	}
-
-
 #if CONFIG_MEDIUM_ALLOCATOR
 #if TARGET_OS_OSX
 #if defined(__x86_64__)
@@ -415,194 +311,7 @@
 			malloc_medium_space_efficient_enabled = (value != 0);
 		}
 	}
-
-	flag = malloc_common_value_for_key_copy(bootargs, medium_madvise_dram_scale_divisor_boot_arg, value_buf, sizeof(value_buf));
-	if (flag) {
-		const char *endp;
-		long value = malloc_common_convert_to_long(flag, &endp);
-		if (!*endp && value >= 0) {
-			magazine_medium_madvise_dram_scale_divisor = (uint64_t)value;
-		} else {
-			malloc_report(ASL_LEVEL_ERR,
-					"malloc_medium_madvise_dram_scale_divisor must be positive - ignored.\n");
-		}
-	}
 #endif // CONFIG_MEDIUM_ALLOCATOR
-}
-
-#if CONFIG_MALLOC_PROCESS_IDENTITY
-
-static void
-_malloc_check_process_identity(void)
-{
-	static const struct {
-		const char *name;
-		malloc_process_identity_t identity;
-	} name_identity_mapping[] = {
-#if TARGET_OS_SIMULATOR
-		{ "launchd_sim",             MALLOC_PROCESS_LAUNCHD, },
-		{ "launchd_sim.development", MALLOC_PROCESS_LAUNCHD, },
-		{ "launchd_sim.debug",       MALLOC_PROCESS_LAUNCHD, },
-#else // TARGET_OS_SIMULATOR
-		{ "launchd",             MALLOC_PROCESS_LAUNCHD, },
-		{ "launchd.development", MALLOC_PROCESS_LAUNCHD, },
-		{ "launchd.debug",       MALLOC_PROCESS_LAUNCHD, },
-		{ "launchd.testing",     MALLOC_PROCESS_LAUNCHD, },
-#endif // TARGET_OS_SIMULATOR
-		{ "logd",                MALLOC_PROCESS_LOGD, },
-		{ "notifyd",             MALLOC_PROCESS_NOTIFYD, },
-
-		{ "mediaparserd",        MALLOC_PROCESS_MEDIAPARSERD, },
-		{ "videocodecd",         MALLOC_PROCESS_VIDEOCODECD, },
-		{ "mediaplaybackd",      MALLOC_PROCESS_MEDIAPLAYBACKD },
-		{ "audiomxd",            MALLOC_PROCESS_AUDIOMXD, },
-		{ "avconferenced",       MALLOC_PROCESS_AVCONFERENCED, },
-		{ "mediaserverd",        MALLOC_PROCESS_MEDIASERVERD, },
-
-		{ "MessagesBlastDoorService", MALLOC_PROCESS_BLASTDOOR_MESSAGES, },
-		{ "MessagesAirlockService",   MALLOC_PROCESS_BLASTDOOR_MESSAGES, },
-		{ "IDSBlastDoorService",      MALLOC_PROCESS_BLASTDOOR_IDS, },
-		{ "IMDPersistenceAgent",      MALLOC_PROCESS_IMDPERSISTENCEAGENT },
-		{ "imagent",                  MALLOC_PROCESS_IMAGENT, },
-
-		{ "ThumbnailExtensionSecure", MALLOC_PROCESS_QUICKLOOK_THUMBNAIL_SECURE, },
-		{ "com.apple.quicklook.extension.previewUI", MALLOC_PROCESS_QUICKLOOK_PREVIEW, },
-		{ "QuickLookUIExtension",     MALLOC_PROCESS_QUICKLOOK_PREVIEW, },
-		{ "ThumbnailExtension",       MALLOC_PROCESS_QUICKLOOK_THUMBNAIL },
-
-		{ "com.apple.WebKit.Networking", MALLOC_PROCESS_WEBKIT_NETWORKING, },
-		{ "com.apple.WebKit.GPU",        MALLOC_PROCESS_WEBKIT_GPU, },
-		{ "MTLCompilerService",          MALLOC_PROCESS_MTLCOMPILERSERVICE },
-		{ "com.apple.WebKit.WebContent", MALLOC_PROCESS_WEBKIT_WEBCONTENT, },
-		{ "com.apple.WebKit.WebContent.CaptivePortal", MALLOC_PROCESS_WEBKIT_WEBCONTENT, },
-
-		{ "callservicesd",       MALLOC_PROCESS_CALLSERVICESD, },
-		{ "maild",               MALLOC_PROCESS_MAILD, },
-		{ "mDNSResponder",       MALLOC_PROCESS_MDNSRESPONDER, },
-		{ "ASVAssetViewer",      MALLOC_PROCESS_ASVASSETVIEWER },
-		{ "identityservicesd",   MALLOC_PROCESS_IDENTITYSERVICESD, },
-		{ "wifid",               MALLOC_PROCESS_WIFID, },
-		{ "fmfd",                MALLOC_PROCESS_FMFD, },
-		{ "searchpartyd",        MALLOC_PROCESS_SEARCHPARTYD, },
-		{ "vmd",                 MALLOC_PROCESS_VMD, },
-		{ "CommCenter",          MALLOC_PROCESS_COMMCENTER, },
-		{ "wifip2pd",            MALLOC_PROCESS_WIFIP2PD, },
-		{ "wifianalyticsd",      MALLOC_PROCESS_WIFIANALYTICSD, },
-	};
-
-	if (getpid() == 1) {
-		malloc_process_identity = MALLOC_PROCESS_LAUNCHD;
-		return;
-	}
-
-	const char *name = getprogname();
-	for (size_t i = 0; i < countof(name_identity_mapping); i++) {
-		if (!strcmp(name, name_identity_mapping[i].name)) {
-			malloc_process_identity = name_identity_mapping[i].identity;
-			break;
-		}
-	}
-}
-
-#if !CONFIG_FEATUREFLAGS_SIMPLE
-#error "must have feature flags"
-#endif
-
-static bool
-_malloc_check_secure_allocator_process_enablement(void)
-{
-	// launchd is special because the feature flag check can't work for it
-	if (malloc_process_identity == MALLOC_PROCESS_LAUNCHD) {
-		return MALLOC_SECURE_ALLOCATOR_LAUNCHD_ENABLED_DEFAULT;
-	}
-
-	if (os_feature_enabled_simple(libmalloc,
-			SecureAllocator_AllInitialProcesses, false)) {
-		switch (malloc_process_identity) {
-		case MALLOC_PROCESS_COMMCENTER:
-			// Enabled by explicit feature flag only
-			break;
-		default:
-			return true;
-		}
-	}
-
-#define ENABLEMENT_CASE(id, name, simulator_default) \
-		case MALLOC_PROCESS_##id: \
-			return os_feature_enabled_simple(libmalloc, \
-					SecureAllocator_process_##name, (simulator_default))
-
-	switch (malloc_process_identity) {
-	ENABLEMENT_CASE(LOGD, logd, true);
-	ENABLEMENT_CASE(NOTIFYD, notifyd, true);
-
-	ENABLEMENT_CASE(MEDIAPARSERD, mediaparserd, true);
-	ENABLEMENT_CASE(VIDEOCODECD, videocodecd, true);
-	ENABLEMENT_CASE(MEDIAPLAYBACKD, mediaplaybackd, true);
-	ENABLEMENT_CASE(AVCONFERENCED, avconferenced, true);
-	ENABLEMENT_CASE(MEDIASERVERD, mediaserverd, true);
-	ENABLEMENT_CASE(AUDIOMXD, audiomxd, true);
-
-	ENABLEMENT_CASE(BLASTDOOR_MESSAGES, blastdoor_messages, true);
-	ENABLEMENT_CASE(BLASTDOOR_IDS, blastdoor_ids, true);
-	ENABLEMENT_CASE(IMDPERSISTENCEAGENT, IMDPersistenceAgent, true);
-	ENABLEMENT_CASE(IMAGENT, imagent, true);
-
-	ENABLEMENT_CASE(QUICKLOOK_THUMBNAIL_SECURE, ThumbnailExtensionSecure, true);
-	ENABLEMENT_CASE(QUICKLOOK_PREVIEW, quicklook_preview, true);
-	ENABLEMENT_CASE(QUICKLOOK_THUMBNAIL, ThumbnailExtension, true);
-
-	ENABLEMENT_CASE(MTLCOMPILERSERVICE, MTLCompilerService, true);
-
-	ENABLEMENT_CASE(CALLSERVICESD, callservicesd, true);
-	ENABLEMENT_CASE(MAILD, maild, true);
-	ENABLEMENT_CASE(MDNSRESPONDER, mDNSResponder, true);
-	ENABLEMENT_CASE(ASVASSETVIEWER, ASVAssetViewer, true);
-	ENABLEMENT_CASE(IDENTITYSERVICESD, identityservicesd, true);
-	ENABLEMENT_CASE(WIFID, wifid, true);
-	ENABLEMENT_CASE(FMFD, fmfd, true);
-	ENABLEMENT_CASE(SEARCHPARTYD, searchpartyd, true);
-	ENABLEMENT_CASE(VMD, vmd, true);
-	ENABLEMENT_CASE(WIFIP2PD, wifip2pd, true);
-	ENABLEMENT_CASE(WIFIANALYTICSD, wifianalyticsd, true);
-
-	ENABLEMENT_CASE(COMMCENTER, CommCenter, true);
-
-	ENABLEMENT_CASE(WEBKIT_NETWORKING, WebKit_Networking, true);
-	ENABLEMENT_CASE(WEBKIT_GPU, WebKit_GPU, true);
-	ENABLEMENT_CASE(WEBKIT_WEBCONTENT, WebKit_WebContent, true);
-
-	default:
-		return false;
-	}
-}
-
-#endif // CONFIG_MALLOC_PROCESS_IDENTITY
-
-static void
-_malloc_init_featureflags(void)
-{
-#if CONFIG_FEATUREFLAGS_SIMPLE
-	bool zero_on_free_feature_enabled = os_feature_enabled_simple(libmalloc,
-			ZeroOnFree, MALLOC_ZERO_POLICY_DEFAULT == MALLOC_ZERO_ON_FREE);
-	bool policy_is_zero_on_free = (malloc_zero_policy == MALLOC_ZERO_ON_FREE);
-	if (zero_on_free_feature_enabled != policy_is_zero_on_free) {
-		malloc_zero_policy = zero_on_free_feature_enabled ?
-				MALLOC_ZERO_ON_FREE : MALLOC_ZERO_NONE;
-	}
-
-	bool secure_allocator = os_feature_enabled_simple(libmalloc,
-			SecureAllocator_SystemWide, false);
-#if CONFIG_MALLOC_PROCESS_IDENTITY
-	if (!secure_allocator && malloc_process_identity != MALLOC_PROCESS_NONE) {
-		secure_allocator = _malloc_check_secure_allocator_process_enablement();
-	}
-#endif
-
-	if (secure_allocator != malloc_xzone_enabled) {
-		malloc_xzone_enabled = secure_allocator;
-	}
-#endif
 }
 
 extern malloc_zone_t *force_asan_init_if_present(void)
@@ -618,11 +327,7 @@
 	char bootargs[1024] = { '\0' };
 	bool allow_bootargs = true;
 #if CONFIG_FEATUREFLAGS_SIMPLE
-	// os_feature_enabled_simple() doesn't work in launchd, but launchd should
-	// be able to read boot-args
-	if (getpid() != 1) {
-		allow_bootargs &= os_feature_enabled_simple(libmalloc, EnableBootArgs, false);
-	}
+	allow_bootargs &= os_feature_enabled_simple(libmalloc, EnableBootArgs, false);
 #endif
 #if defined(_COMM_PAGE_DEV_FIRM)
 	allow_bootargs &= !!*((uint32_t *)_COMM_PAGE_DEV_FIRM);
@@ -634,16 +339,6 @@
 			len > 0) {
 		bootargs[len + 1] = '\0';
 	}
-
-	// Cache the calculation of this "constant", which unfortunately depends on
-	// runtime values of vm_kernel_page_size and vm_page_size
-	malloc_absolute_max_size = _MALLOC_ABSOLUTE_MAX_SIZE;
-
-#if CONFIG_MALLOC_PROCESS_IDENTITY
-	_malloc_check_process_identity();
-#endif
-
-	_malloc_init_featureflags();
 
 	const char **p;
 	const char *malloc_experiments = NULL;
@@ -659,13 +354,6 @@
 		if (strstr(*p, LIBMALLOC_EXPERIMENT_FACTORS_KEY) == *p) {
 			malloc_experiments = *p;
 		}
-#if CONFIG_DEFERRED_RECLAIM
-		if (strstr(*p, LIBMALLOC_DEFERRED_RECLAIM_ENABLE) == *p) {
-			// Turn on the large cache which will place
-			// its free entries in the deferred reclaim buffer
-			large_cache_enabled = 1;
-		}
-#endif /* CONFIG_DEFERRED_RECLAIM */
 	}
 	if (!_malloc_entropy_initialized) {
 		getentropy((void*)malloc_entropy, sizeof(malloc_entropy));
@@ -696,42 +384,15 @@
 
 // WARNING: The passed _malloc_late_init is a stack variable in
 // libSystem_initializer().  We must not hold on to it.
-//
-// WARNING 2: By the time this is called, malloc() is already used
-// a bunch of times (from libobjc, libxpc, ...).
 void
 __malloc_late_init(const struct _malloc_late_init *mli)
 {
 	register_pgm_zone(mli->internal_diagnostics);
 	stack_logging_early_finished(mli);
 	initial_num_zones = malloc_num_zones;
-	
-#if CONFIG_SANITIZER
-	if (malloc_sanitizer_enabled) {
-		sanitizer_reset_environment();
-
-#if TARGET_OS_OSX
-		// Fetch the memory poisoning functions from the upstream ASan runtime
-		sanitizer_fallback_ptrs.memory_poison = _dlsym(RTLD_MAIN_ONLY, "__asan_poison_memory_region");
-		sanitizer_fallback_ptrs.memory_unpoison = _dlsym(RTLD_MAIN_ONLY, "__asan_unpoison_memory_region");
-
-		// Prefer the heap allocation functions from our ASan runtime, if available
-		void *heap_alloc = _dlsym(RTLD_MAIN_ONLY, "__asan_poison_heap_memory_alloc"),
-			 *heap_dealloc = _dlsym(RTLD_MAIN_ONLY, "__asan_poison_heap_memory_free"),
-			 *heap_internal_poison = _dlsym(RTLD_MAIN_ONLY, "__asan_poison_heap_memory_internal");
-		if (heap_alloc && heap_dealloc && heap_internal_poison) {
-			sanitizer_fallback.heap_allocate_poison = heap_alloc;
-			sanitizer_fallback.heap_deallocate_poison = heap_dealloc;
-			sanitizer_fallback.heap_internal_poison = heap_internal_poison;
-		} else {
-			sanitizer_fallback.heap_allocate_poison = &malloc_sanitizer_fallback_allocate_poison;
-			sanitizer_fallback.heap_deallocate_poison = &malloc_sanitizer_fallback_deallocate_poison;
-			sanitizer_fallback.heap_internal_poison = &malloc_sanitizer_fallback_deallocate_poison;
-		}
-#endif
-	}
-#endif
-}
+}
+
+MALLOC_NOEXPORT malloc_zone_t* lite_zone = NULL;
 
 MALLOC_ALWAYS_INLINE
 static inline malloc_zone_t *
@@ -979,12 +640,16 @@
 /*static*/ boolean_t
 has_default_zone0(void)
 {
-	return !has_injected_zone0;
-}
-
-static inline malloc_zone_t *find_registered_zone(const void *, size_t *, bool) __attribute__((always_inline));
+	if (!malloc_zones) {
+		return false;
+	}
+	
+	return initial_default_zone == malloc_zones[0];
+}
+
+static inline malloc_zone_t *find_registered_zone(const void *, size_t *) __attribute__((always_inline));
 static inline malloc_zone_t *
-find_registered_zone(const void *ptr, size_t *returned_size, bool known_non_default)
+find_registered_zone(const void *ptr, size_t *returned_size)
 {
 	// Returns a zone which contains ptr, else NULL
 
@@ -1012,9 +677,9 @@
 	size_t size;
 
 	// We assume that the initial zones will never be unregistered concurrently while this code is running so we can have
-	// a fast path without synchronization.  Callers who really do unregister these (to install their own default zone) need
-	// to ensure they establish their zone setup during initialization and before entering a multi-threaded environment.
-	for (uint32_t i = known_non_default ? 1 : 0; i < initial_num_zones; i++) {
+	// a fast path without locking.  Callers who really do unregister these (to install their own default zone) need to
+	// ensure they establish their zone setup during initialization and before entering a multi-threaded environment.
+	for (uint32_t i = 0; i < initial_num_zones; i++) {
 		zone = malloc_zones[i];
 		size = zone->size(zone, ptr);
 
@@ -1121,7 +786,7 @@
 static void set_flags_from_environment(void);
 
 MALLOC_NOEXPORT void
-malloc_zone_register_while_locked(malloc_zone_t *zone, bool make_default)
+malloc_zone_register_while_locked(malloc_zone_t *zone)
 {
 	size_t protect_size;
 	unsigned i;
@@ -1170,13 +835,6 @@
 		mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);
 	}
 
-	if (make_default) {
-		memmove(&malloc_zones[1], &malloc_zones[0], malloc_num_zones * sizeof(malloc_zone_t *));
-		malloc_zones[0] = zone;
-	} else {
-		malloc_zones[malloc_num_zones] = zone;
-	}
-
 	/* <rdar://problem/12871662> This store-increment needs to be visible in the correct
 	 * order to any threads in find_registered_zone, such that if the incremented value
 	 * in malloc_num_zones is visible then the pointer write before it must also be visible.
@@ -1185,18 +843,12 @@
 	 * ensure the proper store-release operation is performed is to use OSAtomic*Barrier
 	 * to update malloc_num_zones.
 	 */
+	malloc_zones[malloc_num_zones] = zone;
 	OSAtomicIncrement32Barrier(&malloc_num_zones);
 
 	/* Finally, now that the zone is registered, disallow write access to the
 	 * malloc_zones array */
 	mprotect(malloc_zones, protect_size, PROT_READ);
-
-	// ASan and others interpose on mprotect() to ensure their zone is always at position 0.
-	if (make_default && malloc_zones[0] != zone) {
-		has_injected_zone0 = true;
-		malloc_slowpath_update();
-	}
-
 	//malloc_report(ASL_LEVEL_INFO, "Registered malloc_zone %p in malloc_zones %p [%u zones, %u bytes]\n", zone, malloc_zones,
 	// malloc_num_zones, protect_size);
 }
@@ -1211,9 +863,6 @@
 {
 	phys_ncpus = *(uint8_t *)(uintptr_t)_COMM_PAGE_PHYSICAL_CPUS;
 	logical_ncpus = *(uint8_t *)(uintptr_t)_COMM_PAGE_LOGICAL_CPUS;
-#if CONFIG_MAGAZINE_PER_CLUSTER
-	ncpuclusters = *(uint8_t *)(uintptr_t)_COMM_PAGE_CPU_CLUSTERS;
-#endif // CONFIG_MAGAZINE_PER_CLUSTER
 
 	if (0 != (logical_ncpus % phys_ncpus)) {
 		MALLOC_REPORT_FATAL_ERROR(logical_ncpus % phys_ncpus,
@@ -1250,126 +899,70 @@
 		max_medium_magazines = max_magazines;
 	}
 
-#if CONFIG_MAGAZINE_PER_CLUSTER && CONFIG_FEATUREFLAGS_SIMPLE
-	if (ncpuclusters == 1) {
-		// Not with the other feature flag checks because ncpuclusters needs to
-		// be initialized first
-		bool secure_allocator_single_cluster = os_feature_enabled_simple(
-				libmalloc, SecureAllocator_SingleCluster, false);
-		if (malloc_xzone_enabled && !secure_allocator_single_cluster) {
-			malloc_xzone_enabled = false;
-		}
-	}
-#endif // CONFIG_MAGAZINE_PER_CLUSTER
-
-	_malloc_detect_interposition();
-
 	set_flags_from_environment(); // will only set flags up to two times
 
-
-#if CONFIG_SANITIZER
-	malloc_sanitizer_enabled = sanitizer_should_enable();
-#endif
-	
 #if CONFIG_NANOZONE
 	// TODO: envp should be passed down from Libsystem
 	const char **envp = (const char **)*_NSGetEnviron();
-	
-	// Force magazine_malloc when:
-	// - sanitizer is enabled, to avoid speculative out-of-bounds
-	//   use-after-free reads that nano/nanov2 performs, OR
-	// - MallocScribble is enabled, which nanov2 does not implement
-	// - MallocCheckZeroOnFreeCorruption sampling is enabled, which nanov2 does
-	//   not implement
-	// - xzone malloc is enabled
-	if (!malloc_xzone_enabled &&
-			!malloc_sanitizer_enabled &&
-			!(malloc_debug_flags & MALLOC_DO_SCRIBBLE) &&
-			!malloc_zero_on_free_sample_period) {
-		nano_common_init(envp, apple, bootargs);
-	}
-#endif // CONFIG_NANOZONE
-
-
-	if (!initial_xzone_zone) {
-		initial_scalable_zone = create_scalable_zone(0, malloc_debug_flags);
-		malloc_set_zone_name(initial_scalable_zone, DEFAULT_MALLOC_ZONE_STRING);
-		malloc_zone_register_while_locked(initial_scalable_zone, /*make_default=*/true);
+	nano_common_init(envp, apple, bootargs);
+#endif
+
+	const uint32_t k_max_zones = 2;
+	malloc_zone_t *zone_stack[k_max_zones];
+	const char *name_stack[k_max_zones];
+	uint32_t num_zones = 0;
+
+	initial_scalable_zone = create_scalable_zone(0, malloc_debug_flags);
+	zone_stack[num_zones] = initial_scalable_zone;
+	name_stack[num_zones] = DEFAULT_MALLOC_ZONE_STRING;
+	num_zones++;
 
 #if CONFIG_NANOZONE
-		nano_common_configure();
-
-		malloc_zone_t *helper_zone = initial_scalable_zone;
-
-		if (_malloc_engaged_nano == NANO_V2) {
-			initial_nano_zone = nanov2_create_zone(helper_zone, malloc_debug_flags);
-		}
-
-		if (initial_nano_zone) {
-			malloc_set_zone_name(initial_nano_zone, DEFAULT_MALLOC_ZONE_STRING);
-			malloc_set_zone_name(helper_zone, MALLOC_HELPER_ZONE_STRING);
-			malloc_zone_register_while_locked(initial_nano_zone, /*make_default=*/true);
-		}
+	nano_common_configure();
+
+	malloc_zone_t *helper_zone = zone_stack[num_zones - 1];
+	malloc_zone_t *nano_zone = NULL;
+
+	if (_malloc_engaged_nano == NANO_V2) {
+		nano_zone = nanov2_create_zone(helper_zone, malloc_debug_flags);
+	} else if (_malloc_engaged_nano == NANO_V1) {
+		nano_zone = nano_create_zone(helper_zone, malloc_debug_flags);
+	}
+
+	if (nano_zone) {
+		initial_nano_zone = nano_zone;
+		zone_stack[num_zones] = nano_zone;
+		name_stack[num_zones] = DEFAULT_MALLOC_ZONE_STRING;
+		name_stack[num_zones - 1] = MALLOC_HELPER_ZONE_STRING;
+		num_zones++;
+	}
 #endif
-	}
-
-#if CONFIG_SANITIZER
-	if (malloc_sanitizer_enabled) {
-		malloc_zone_t *wrapped_zone = malloc_zones[0];
-		malloc_zone_t *sanitizer_zone = sanitizer_create_zone(wrapped_zone);
-		malloc_zone_register_while_locked(sanitizer_zone, /*make_default=*/true);
-	}
-#endif
-
-	// Initialize slowpath check after we've registered zones so that
-	// malloc_num_zones check is meaningful
-	malloc_slowpath_update();
+
+	MALLOC_ASSERT(num_zones <= k_max_zones);
+	initial_default_zone = zone_stack[num_zones - 1];
+
+	// 2 separate loops: malloc_set_zone_name already requires a working allocator.
+	for (int i = num_zones - 1; i >= 0; i--) malloc_zone_register_while_locked(zone_stack[i]);
+	for (int i = num_zones - 1; i >= 0; i--) malloc_set_zone_name(zone_stack[i], name_stack[i]);
 
 	initial_num_zones = malloc_num_zones;
-
-#if CONFIG_DEFERRED_RECLAIM
-	if (large_cache_enabled) {
-		kern_return_t kr = mvm_deferred_reclaim_init();
-		if (kr != KERN_SUCCESS) {
-			large_cache_enabled = false;
-			malloc_report(ASL_LEVEL_ERR, "Unable to set up reclaim buffer (%d) - disabling large cache\n", kr);
-		}
-	}
-#endif /* CONFIG_DEFERRED_RECLAIM */
-
-#if CONFIG_MEDIUM_ALLOCATOR
-	uint64_t memsize = platform_hw_memsize();
-	if (memsize >= 8 * magazine_medium_madvise_dram_scale_divisor) {
-		magazine_medium_madvise_window_scale_factor = 8;
-	} else if (memsize >= 4 * magazine_medium_madvise_dram_scale_divisor) {
-		magazine_medium_madvise_window_scale_factor = 4;
-	} else if (memsize >= 2 * magazine_medium_madvise_dram_scale_divisor) {
-		magazine_medium_madvise_window_scale_factor = 2;
-	} else {
-		magazine_medium_madvise_window_scale_factor = 1;
-	}
-#endif /* CONFIG_MEDIUM_ALLOCATOR */
 
 	// malloc_report(ASL_LEVEL_INFO, "%d registered zones\n", malloc_num_zones);
 	// malloc_report(ASL_LEVEL_INFO, "malloc_zones is at %p; malloc_num_zones is at %p\n", (unsigned)&malloc_zones,
 	// (unsigned)&malloc_num_zones);
 }
 
-static bool
-enable_pgm(void)
-{
-	bool other_debug_tool = has_injected_zone0 || malloc_sanitizer_enabled;
-	return !other_debug_tool && pgm_should_enable();
-}
-
+static void make_last_zone_default_zone(void);
 static void
 register_pgm_zone(bool internal_diagnostics)
 {
-	pgm_init_config(internal_diagnostics);
-	if (enable_pgm()) {
+	if (pguard_enabled(internal_diagnostics)) {
 		malloc_zone_t *wrapped_zone = malloc_zones[0];
-		malloc_zone_t *pgm_zone = pgm_create_zone(wrapped_zone);
-		malloc_zone_register_while_locked(pgm_zone, /*make_default=*/true);
+		malloc_zone_t *pgm_zone = pguard_create_zone(wrapped_zone);
+		malloc_zone_register_while_locked(pgm_zone);
+		make_last_zone_default_zone();
+		initial_default_zone = pgm_zone;
+		malloc_set_zone_name(pgm_zone, MALLOC_PGUARD_ZONE_STRING);
 	}
 }
 
@@ -1436,6 +1029,26 @@
 #endif
 }
 
+malloc_zone_t *
+malloc_default_purgeable_zone(void)
+{
+	static malloc_zone_t *dpz;
+
+	if (!dpz) {
+		//
+		// PR_7288598: Must pass a *scalable* zone (szone) as the helper for create_purgeable_zone().
+		// Take care that the zone so obtained is not subject to interposing.
+		//
+		malloc_zone_t *tmp = create_purgeable_zone(0, initial_scalable_zone, malloc_debug_flags);
+		malloc_zone_register(tmp);
+		malloc_set_zone_name(tmp, DEFAULT_PUREGEABLE_ZONE_STRING);
+		if (!OSAtomicCompareAndSwapPtrBarrier(NULL, tmp, (void**)&dpz)) {
+			malloc_destroy_zone(tmp);
+		}
+	}
+	return dpz;
+}
+
 static void
 set_flags_from_environment(void)
 {
@@ -1444,7 +1057,7 @@
 	const char **p;
 	const char *c;
 
-#if defined(__LP64__)
+#if __LP64__
 	malloc_debug_flags = MALLOC_ABORT_ON_CORRUPTION; // Set always on 64-bit processes
 #else
 	int libSystemVersion = NSVersionOfLinkTimeLibrary("System");
@@ -1454,16 +1067,6 @@
 		malloc_debug_flags = MALLOC_ABORT_ON_CORRUPTION;
 	}
 #endif
-
-#if TARGET_OS_OSX
-	// rdar://99288027
-	if (!dyld_program_sdk_at_least(dyld_platform_version_macOS_13_0)) {
-		if (malloc_zero_policy == MALLOC_ZERO_ON_FREE) {
-			malloc_zero_policy = MALLOC_ZERO_ON_ALLOC;
-		}
-	}
-#else // TARGET_OS_OSX
-#endif // TARGET_OS_OSX
 
 	/*
 	 * Given that all environment variables start with "Malloc" we optimize by scanning quickly
@@ -1533,11 +1136,8 @@
 	if (getenv("MallocTracing")) {
 		malloc_tracing_enabled = true;
 	}
-	if (getenv("MallocSimpleStackLogging")) {
-		malloc_simple_stack_logging = true;
-	}
-
-#if defined(__LP64__)
+
+#if __LP64__
 /* initialization above forces MALLOC_ABORT_ON_CORRUPTION of 64-bit processes */
 #else
 	flag = getenv("MallocCorruptionAbort");
@@ -1595,15 +1195,9 @@
 	}
 #endif // RDAR_48993662
 	if (flag) {
-
-		int value = (int)strtol(flag, NULL, 0);
+		int value = (unsigned)strtol(flag, NULL, 0);
 		if (value == 0) {
 			malloc_report(ASL_LEVEL_INFO, "Maximum magazines defaulted to %d\n", max_magazines);
-#if CONFIG_MAGAZINE_PER_CLUSTER
-		} else if (value == UINT16_MAX) {
-			max_magazines = ncpuclusters;
-			malloc_report(ASL_LEVEL_INFO, "Maximum magazines limited to number of logical CPU clusters (%d)\n", max_magazines);
-#endif // CONFIG_MAGAZINE_PER_CLUSTER
 		} else if (value < 0) {
 			malloc_report(ASL_LEVEL_ERR, "Maximum magazines must be positive - ignored.\n");
 		} else if (value > logical_ncpus) {
@@ -1652,10 +1246,7 @@
 			aggressive_madvise_enabled = (value == 1);
 #endif // CONFIG_AGGRESSIVE_MADVISE
 #if CONFIG_LARGE_CACHE
-			// Disable the large cache in space efficient mode
-			if (value != 0){
-				large_cache_enabled = 0;
-			}
+			large_cache_enabled = (value == 0);
 #endif // CONFIG_LARGE_CACHE
 			malloc_space_efficient_enabled = (value == 1);
 			// consider disabling medium magazine if aggressive madvise is not sufficient
@@ -1765,51 +1356,6 @@
 		}
 	}
 #endif // CONFIG_RECIRC_DEPOT
-
-	flag = getenv("MallocZeroOnFree");
-	if (flag) {
-		const char *endp;
-		long value = malloc_common_convert_to_long(flag, &endp);
-		if (!*endp && endp != flag && (value == 0 || value == 1)) {
-			malloc_zero_policy = value ? MALLOC_ZERO_ON_FREE : MALLOC_ZERO_NONE;
-		} else {
-			malloc_report(ASL_LEVEL_ERR, "MallocZeroOnFree must be 0 or 1.\n");
-		}
-	}
-
-	flag = getenv("MallocZeroOnAlloc");
-	if (flag) {
-		const char *endp;
-		long value = malloc_common_convert_to_long(flag, &endp);
-		if (!*endp && endp != flag && (value == 0 || value == 1)) {
-			malloc_zero_policy = value ? MALLOC_ZERO_ON_ALLOC : MALLOC_ZERO_NONE;
-		} else {
-			malloc_report(ASL_LEVEL_ERR, "MallocZeroOnAlloc must be 0 or 1.\n");
-		}
-	}
-
-	flag = getenv("MallocCheckZeroOnFreeCorruption");
-	if (flag) {
-		int value = (int)strtol(flag, NULL, 0);
-		if (value > 0) {
-			malloc_zero_on_free_sample_period = value;
-		} else {
-			malloc_report(ASL_LEVEL_ERR,
-					"malloc_zero_on_free_sample_period must be positive - ignored.\n");
-		}
-	}
-
-	flag = getenv("MallocSecureAllocator");
-	if (flag) {
-		const char *endp;
-		long value = malloc_common_convert_to_long(flag, &endp);
-		if (!*endp && endp != flag && (value == 0 || value == 1)) {
-			malloc_xzone_enabled = value;
-		} else {
-			malloc_report(ASL_LEVEL_ERR, "MallocSecureAllocator must be 0 or 1.\n");
-		}
-	}
-
 	if (getenv("MallocHelp")) {
 		malloc_report(ASL_LEVEL_INFO,
 				"environment variables that can be set for debug:\n"
@@ -1830,8 +1376,6 @@
 				"  MallocCorruptionAbort is always set on 64-bit processes\n"
 				"- MallocErrorAbort to abort on any malloc error, including out of memory\n"\
 				"- MallocTracing to emit kdebug trace points on malloc entry points\n"\
-				"- MallocZeroOnFree to enable or disable zero-on-free behavior (for debugging only)\n"\
-				"- MallocCheckZeroOnFreeCorruption to enable zero-on-free corruption detection\n"\
 				"- MallocHelp - this help!\n");
 	}
 }
@@ -1842,20 +1386,30 @@
 	malloc_zone_t *zone;
 
 	/* start_size doesn't actually appear to be used, but we test anyway. */
-	if (start_size > malloc_absolute_max_size) {
+	if (start_size > MALLOC_ABSOLUTE_MAX_SIZE) {
 		return NULL;
 	}
 
 	zone = create_scalable_zone(start_size, flags | malloc_debug_flags);
 	malloc_zone_register(zone);
-
-#if CONFIG_PGM_WRAP_CUSTOM_ZONES
-	if (enable_pgm()) {
-		zone = pgm_create_zone(zone);
-		malloc_zone_register(zone);
-	}
-#endif
 	return zone;
+}
+
+static void
+make_last_zone_default_zone(void)
+{
+	unsigned protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
+	mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);
+
+	malloc_zone_t *last_zone = malloc_zones[malloc_num_zones - 1];
+
+	// assert(zone == malloc_zones[malloc_num_zones - 1];
+	for (int i = malloc_num_zones - 1; i > 0; --i) {
+		malloc_zones[i] = malloc_zones[i - 1];
+	}
+	malloc_zones[0] = last_zone;
+
+	mprotect(malloc_zones, protect_size, PROT_READ);
 }
 
 /*
@@ -1870,6 +1424,7 @@
 	zone = create_legacy_scalable_zone(0, malloc_debug_flags);
 
 	MALLOC_LOCK();
+	malloc_zone_register_while_locked(zone);
 
 	//
 	// Establish the legacy scalable zone just created as the default zone.
@@ -1880,7 +1435,7 @@
 	}
 	malloc_set_zone_name(zone, DEFAULT_MALLOC_ZONE_STRING);
 
-	malloc_zone_register_while_locked(zone, /*make_default=*/true);
+	make_last_zone_default_zone();
 	MALLOC_UNLOCK();
 }
 
@@ -1981,38 +1536,46 @@
 	malloc_check_start += malloc_check_each;
 }
 
+__options_decl(malloc_zone_options_t, unsigned, {
+	MZ_NONE  = 0x0,
+	MZ_POSIX = 0x1,
+	MZ_C11   = 0x2,
+});
+
+static inline void
+malloc_set_errno_fast(malloc_zone_options_t mzo, int err)
+{
+	if (mzo & MZ_POSIX) {
+#if TARGET_OS_SIMULATOR
+		errno = err;
+#else
+		(*_pthread_errno_address_direct()) = err;
+#endif
+	}
+}
+
 MALLOC_NOINLINE
 static void *
-_malloc_zone_malloc_instrumented_or_legacy(malloc_zone_t *zone, size_t size,
-		malloc_zone_options_t mzo)
-{
-	uint64_t type_id = malloc_get_tsd_type_id();
-	MALLOC_TRACE(TRACE_malloc | DBG_FUNC_START, (uintptr_t)zone, size, type_id,
-			0);
+_malloc_zone_malloc(malloc_zone_t *zone, size_t size, malloc_zone_options_t mzo)
+{
+	MALLOC_TRACE(TRACE_malloc | DBG_FUNC_START, (uintptr_t)zone, size, 0, 0);
 
 	void *ptr = NULL;
 
 	if (malloc_check_start) {
 		internal_check();
 	}
-	if (size > malloc_absolute_max_size) {
+	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
 		goto out;
 	}
 
-	ptr = zone->malloc(zone, size);
+	ptr = zone->malloc(zone, size);		// if lite zone is passed in then we still call the lite methods
 
 	if (os_unlikely(malloc_logger)) {
-		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE,
-				(uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
-	}
-
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS, "malloc (%p/%llu): ",
-				ptr, (unsigned long long)size);
-	}
-
-	MALLOC_TRACE(TRACE_malloc | DBG_FUNC_END, (uintptr_t)zone, size,
-			(uintptr_t)ptr, type_id);
+		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
+	}
+
+	MALLOC_TRACE(TRACE_malloc | DBG_FUNC_END, (uintptr_t)zone, size, (uintptr_t)ptr, 0);
 out:
 	if (os_unlikely(ptr == NULL)) {
 		malloc_set_errno_fast(mzo, ENOMEM);
@@ -2020,70 +1583,10 @@
 	return ptr;
 }
 
-static void *
-_malloc_zone_malloc(malloc_zone_t *zone, size_t size, malloc_zone_options_t mzo)
-{
-	if (zone == default_zone && !lite_zone) {
-		// Eagerly resolve the virtual default zone to make the zone version
-		// check accurate
-		zone = malloc_zones[0];
-	}
-
-	if (os_unlikely(malloc_slowpath || malloc_logger || zone->version < 13)) {
-		return _malloc_zone_malloc_instrumented_or_legacy(zone, size, mzo);
-	}
-
-	if (os_unlikely(size > malloc_absolute_max_size)) {
-		malloc_set_errno_fast(mzo, ENOMEM);
-		return NULL;
-	}
-
-	// zone versions >= 13 set errno on failure so we can tail-call
-	return zone->malloc(zone, size);
-}
-
-MALLOC_NOINLINE
 void *
 malloc_zone_malloc(malloc_zone_t *zone, size_t size)
 {
 	return _malloc_zone_malloc(zone, size, MZ_NONE);
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_zone_calloc_instrumented_or_legacy(malloc_zone_t *zone,
-		size_t num_items, size_t size, malloc_zone_options_t mzo)
-{
-	uint64_t type_id = malloc_get_tsd_type_id();
-	MALLOC_TRACE(TRACE_calloc | DBG_FUNC_START, (uintptr_t)zone, num_items,
-			size, type_id);
-
-	void *ptr;
-	if (malloc_check_start) {
-		internal_check();
-	}
-
-	ptr = zone->calloc(zone, num_items, size);
-
-	if (os_unlikely(malloc_logger)) {
-		uint32_t logger_type = MALLOC_LOG_TYPE_ALLOCATE |
-				MALLOC_LOG_TYPE_HAS_ZONE | MALLOC_LOG_TYPE_CLEARED;
-		malloc_logger(logger_type, (uintptr_t)zone,
-				(uintptr_t)(num_items * size), 0, (uintptr_t)ptr, 0);
-	}
-
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS,
-				"calloc (%p/%llu*%llu): ", ptr, (unsigned long long)num_items,
-				(unsigned long long)size);
-	}
-
-	MALLOC_TRACE(TRACE_calloc | DBG_FUNC_END, (uintptr_t)zone, num_items, size,
-			(uintptr_t)ptr);
-	if (os_unlikely(ptr == NULL)) {
-		malloc_set_errno_fast(mzo, ENOMEM);
-	}
-	return ptr;
 }
 
 MALLOC_NOINLINE
@@ -2091,21 +1594,27 @@
 _malloc_zone_calloc(malloc_zone_t *zone, size_t num_items, size_t size,
 		malloc_zone_options_t mzo)
 {
-	if (zone == default_zone && !lite_zone) {
-		// Eagerly resolve the virtual default zone to make the zone version
-		// check accurate
-		zone = malloc_zones[0];
-	}
-
-	if (os_unlikely(malloc_slowpath || malloc_logger || zone->version < 13)) {
-		return _malloc_zone_calloc_instrumented_or_legacy(zone, num_items, size, mzo);
-	}
-
-	// zone versions >= 13 set errno on failure so we can tail-call
-	return zone->calloc(zone, num_items, size);
-}
-
-MALLOC_NOINLINE
+	MALLOC_TRACE(TRACE_calloc | DBG_FUNC_START, (uintptr_t)zone, num_items, size, 0);
+
+	void *ptr;
+	if (malloc_check_start) {
+		internal_check();
+	}
+
+	ptr = zone->calloc(zone, num_items, size);
+
+	if (os_unlikely(malloc_logger)) {
+		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE | MALLOC_LOG_TYPE_CLEARED, (uintptr_t)zone,
+				(uintptr_t)(num_items * size), 0, (uintptr_t)ptr, 0);
+	}
+
+	MALLOC_TRACE(TRACE_calloc | DBG_FUNC_END, (uintptr_t)zone, num_items, size, (uintptr_t)ptr);
+	if (os_unlikely(ptr == NULL)) {
+		malloc_set_errno_fast(mzo, ENOMEM);
+	}
+	return ptr;
+}
+
 void *
 malloc_zone_calloc(malloc_zone_t *zone, size_t num_items, size_t size)
 {
@@ -2116,32 +1625,23 @@
 static void *
 _malloc_zone_valloc(malloc_zone_t *zone, size_t size, malloc_zone_options_t mzo)
 {
-	uint64_t type_id = malloc_get_tsd_type_id();
-	MALLOC_TRACE(TRACE_valloc | DBG_FUNC_START, (uintptr_t)zone, size, type_id,
-			0);
+	MALLOC_TRACE(TRACE_valloc | DBG_FUNC_START, (uintptr_t)zone, size, 0, 0);
 
 	void *ptr = NULL;
 	if (malloc_check_start) {
 		internal_check();
 	}
-	if (size > malloc_absolute_max_size) {
+	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
 		goto out;
 	}
 
 	ptr = zone->valloc(zone, size);
 
 	if (os_unlikely(malloc_logger)) {
-		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE,
-				(uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
-	}
-
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS, "valloc (%p/%llu): ",
-				ptr, (unsigned long long)size);
-	}
-
-	MALLOC_TRACE(TRACE_valloc | DBG_FUNC_END, (uintptr_t)zone, size,
-			(uintptr_t)ptr, type_id);
+		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
+	}
+
+	MALLOC_TRACE(TRACE_valloc | DBG_FUNC_END, (uintptr_t)zone, size, (uintptr_t)ptr, 0);
 out:
 	if (os_unlikely(ptr == NULL)) {
 		malloc_set_errno_fast(mzo, ENOMEM);
@@ -2149,58 +1649,35 @@
 	return ptr;
 }
 
-MALLOC_NOINLINE
 void *
 malloc_zone_valloc(malloc_zone_t *zone, size_t size)
 {
 	return _malloc_zone_valloc(zone, size, MZ_NONE);
 }
 
-// We have this function so code within libmalloc can call it without going
-// through the (potentially interposed) dyld symbol stub
-static void *
-_malloc_zone_realloc(malloc_zone_t *zone, void *ptr, size_t size)
-{
-	uint64_t type_id = malloc_get_tsd_type_id();
-	MALLOC_TRACE(TRACE_realloc | DBG_FUNC_START, (uintptr_t)zone,
-			(uintptr_t)ptr, size, type_id);
+void *
+malloc_zone_realloc(malloc_zone_t *zone, void *ptr, size_t size)
+{
+	MALLOC_TRACE(TRACE_realloc | DBG_FUNC_START, (uintptr_t)zone, (uintptr_t)ptr, size, 0);
 
 	void *new_ptr;
 	if (malloc_check_start) {
 		internal_check();
 	}
-	if (size > malloc_absolute_max_size) {
+	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
 		return NULL;
 	}
 
 	new_ptr = zone->realloc(zone, ptr, size);
 	
 	if (os_unlikely(malloc_logger)) {
-		uint32_t logger_type = MALLOC_LOG_TYPE_ALLOCATE |
-			MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE;
-		malloc_logger(logger_type, (uintptr_t)zone, (uintptr_t)ptr,
-				(uintptr_t)size, (uintptr_t)new_ptr, 0);
-	}
-
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS,
-				"realloc (%p->%p/%llu): ", ptr, new_ptr,
-				(unsigned long long)size);
-	}
-
-	MALLOC_TRACE(TRACE_realloc | DBG_FUNC_END, (uintptr_t)zone, (uintptr_t)ptr,
-			size, (uintptr_t)new_ptr);
+		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone,
+				(uintptr_t)ptr, (uintptr_t)size, (uintptr_t)new_ptr, 0);
+	}
+	MALLOC_TRACE(TRACE_realloc | DBG_FUNC_END, (uintptr_t)zone, (uintptr_t)ptr, size, (uintptr_t)new_ptr);
 	return new_ptr;
 }
 
-MALLOC_NOINLINE
-void *
-malloc_zone_realloc(malloc_zone_t *zone, void *ptr, size_t size)
-{
-	return _malloc_zone_realloc(zone, ptr, size);
-}
-
-MALLOC_NOINLINE
 void
 malloc_zone_free(malloc_zone_t *zone, void *ptr)
 {
@@ -2209,9 +1686,6 @@
 	if (os_unlikely(malloc_logger)) {
 		malloc_logger(MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)ptr, 0, 0, 0);
 	}
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS, "malloc_zone_free (%p): ", ptr);
-	}
 	if (malloc_check_start) {
 		internal_check();
 	}
@@ -2226,10 +1700,6 @@
 
 	if (os_unlikely(malloc_logger)) {
 		malloc_logger(MALLOC_LOG_TYPE_DEALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)ptr, 0, 0, 0);
-	}
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS, "free (%p/%llu): ",
-				ptr, (unsigned long long)size);
 	}
 	if (malloc_check_start) {
 		internal_check();
@@ -2244,7 +1714,7 @@
 	if (!ptr) {
 		return NULL;
 	} else {
-		return find_registered_zone(ptr, NULL, false);
+		return find_registered_zone(ptr, NULL);
 	}
 }
 
@@ -2253,31 +1723,25 @@
 _malloc_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size,
 		malloc_zone_options_t mzo)
 {
-	uint64_t type_id = malloc_get_tsd_type_id();
-	MALLOC_TRACE(TRACE_memalign | DBG_FUNC_START, (uintptr_t)zone, alignment,
-			size, type_id);
+	MALLOC_TRACE(TRACE_memalign | DBG_FUNC_START, (uintptr_t)zone, alignment, size, 0);
 
 	void *ptr = NULL;
 	int err = ENOMEM;
-	// Version must be >= 5 to look at the new memalign field.
-	if (zone->version < 5) {
+	if (zone->version < 5) { // Version must be >= 5 to look at the new memalign field.
 		goto out;
 	}
 	if (malloc_check_start) {
 		internal_check();
 	}
-	if (size > malloc_absolute_max_size) {
+	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
 		goto out;
 	}
-	// excludes 0 == alignment
-	// relies on sizeof(void *) being a power of two.
-	if (alignment < sizeof(void *) ||
-			0 != (alignment & (alignment - 1))) {
+	if (alignment < sizeof(void *) ||			  // excludes 0 == alignment
+			0 != (alignment & (alignment - 1))) { // relies on sizeof(void *) being a power of two.
 		err = EINVAL;
 		goto out;
 	}
-	// C11 requires size to be a multiple of alignment
-	if ((mzo & MZ_C11) && (size & (alignment - 1)) != 0) {
+	if ((mzo & MZ_C11) && (size & (alignment - 1)) != 0) { /* C11 requires size to be a multiple of alignment */
 		err = EINVAL;
 		goto out;
 	}
@@ -2288,17 +1752,10 @@
 	ptr = zone->memalign(zone, alignment, size);
 
 	if (os_unlikely(malloc_logger)) {
-		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE,
-				(uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
-	}
-	if (os_unlikely(malloc_simple_stack_logging)) {
-		malloc_report(MALLOC_SIMPLE_STACK_LOGGING_FLAGS,
-				"memalign (%p/%llu,%llu): ", ptr, (unsigned long long)alignment,
-				(unsigned long long)size);
-	}
-
-	MALLOC_TRACE(TRACE_memalign | DBG_FUNC_END, (uintptr_t)zone, alignment,
-			size, (uintptr_t)ptr);
+		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
+	}
+
+	MALLOC_TRACE(TRACE_memalign | DBG_FUNC_END, (uintptr_t)zone, alignment, size, (uintptr_t)ptr);
 
 out:
 	if (os_unlikely(ptr == NULL)) {
@@ -2309,7 +1766,6 @@
 	return ptr;
 }
 
-MALLOC_NOINLINE
 void *
 malloc_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size)
 {
@@ -2343,7 +1799,7 @@
 malloc_zone_register(malloc_zone_t *zone)
 {
 	MALLOC_LOCK();
-	malloc_zone_register_while_locked(zone, false);
+	malloc_zone_register_while_locked(zone);
 	MALLOC_UNLOCK();
 }
 
@@ -2375,9 +1831,9 @@
 
 		mprotect(malloc_zones, protect_size, PROT_READ);
 
-		// MAX(num_zones, 1) retains the fast path in find_registered_zone() for zone 0 even
+		// MAX(num_zones, 1) enables the fast path in find_registered_zone() for zone 0 even
 		// if it is a custom zone, e.g., ASan and user zones.
-		initial_num_zones = MAX(MIN(malloc_num_zones, initial_num_zones), 1);
+		initial_num_zones = MIN(MAX(malloc_num_zones, 1), initial_num_zones);
 
 		// Exchange the roles of the FRZ counters. The counter that has captured the number of threads presently
 		// executing *inside* find_registered_zone is swapped with the counter drained to zero last time through.
@@ -2402,32 +1858,24 @@
 void
 malloc_set_zone_name(malloc_zone_t *z, const char *name)
 {
-	// TODO: save and restore permissions generally
-	if (z != initial_xzone_zone) {
-		mprotect(z, sizeof(malloc_zone_t), PROT_READ | PROT_WRITE);
-	}
+	char *newName;
+
+	mprotect(z, sizeof(malloc_zone_t), PROT_READ | PROT_WRITE);
 	if (z->zone_name) {
-		malloc_zone_t *old_zone = find_registered_zone(z->zone_name, NULL, false);
-		if (old_zone) {
-			malloc_zone_free(old_zone, (char *)z->zone_name);
-		}
+		free((char *)z->zone_name);
 		z->zone_name = NULL;
 	}
 	if (name) {
 		size_t buflen = strlen(name) + 1;
-		if (_dyld_is_memory_immutable(name, buflen)) {
-			z->zone_name = name;
+		newName = _malloc_zone_malloc(z, buflen, MZ_NONE);
+		if (newName) {
+			strlcpy(newName, name, buflen);
+			z->zone_name = (const char *)newName;
 		} else {
-			char *name_copy = _malloc_zone_malloc(z, buflen, MZ_NONE);
-			if (name_copy) {
-				strlcpy(name_copy, name, buflen);
-				z->zone_name = name_copy;
-			}
-		}
-	}
-	if (z != initial_xzone_zone) {
-		mprotect(z, sizeof(malloc_zone_t), PROT_READ);
-	}
+			z->zone_name = NULL;
+		}
+	}
+	mprotect(z, sizeof(malloc_zone_t), PROT_READ);
 }
 
 const char *
@@ -2436,8 +1884,30 @@
 	return zone->zone_name;
 }
 
-void
-find_zone_and_free(void *ptr, bool known_non_default)
+
+/*********	Generic ANSI callouts	************/
+
+void *
+malloc(size_t size)
+{
+	return _malloc_zone_malloc(default_zone, size, MZ_POSIX);
+}
+
+void *
+aligned_alloc(size_t alignment, size_t size)
+{
+	return _malloc_zone_memalign(default_zone, alignment, size,
+	    MZ_POSIX | MZ_C11);
+}
+
+void *
+calloc(size_t num_items, size_t size)
+{
+	return _malloc_zone_calloc(default_zone, num_items, size, MZ_POSIX);
+}
+
+void
+free(void *ptr)
 {
 	malloc_zone_t *zone;
 	size_t size;
@@ -2445,7 +1915,7 @@
 		return;
 	}
 
-	zone = find_registered_zone(ptr, &size, known_non_default);
+	zone = find_registered_zone(ptr, &size);
 	if (!zone) {
 		int flags = MALLOC_REPORT_DEBUG | MALLOC_REPORT_NOLOG;
 		if ((malloc_debug_flags & (MALLOC_ABORT_ON_CORRUPTION | MALLOC_ABORT_ON_ERROR))) {
@@ -2460,59 +1930,8 @@
 	}
 }
 
-
-/*********	Generic ANSI callouts	************/
-
-MALLOC_NOINLINE
 void *
-malloc(size_t size)
-{
-	return _malloc_zone_malloc(default_zone, size, MZ_POSIX);
-}
-
-MALLOC_NOINLINE
-void *
-aligned_alloc(size_t alignment, size_t size)
-{
-	return _malloc_zone_memalign(default_zone, alignment, size,
-	    MZ_POSIX | MZ_C11);
-}
-
-MALLOC_NOINLINE
-void *
-calloc(size_t num_items, size_t size)
-{
-	return _malloc_zone_calloc(default_zone, num_items, size, MZ_POSIX);
-}
-
-MALLOC_NOINLINE
-void
-free(void *ptr)
-{
-	if (!ptr) {
-		return;
-	}
-
-	malloc_zone_t *zone0 = malloc_zones[0];
-	if (os_unlikely(malloc_slowpath ||
-				malloc_logger ||
-				zone0->version < 13)) {
-		find_zone_and_free(ptr, false);
-		return;
-	}
-
-
-	if (zone0->try_free_default) {
-		zone0->try_free_default(zone0, ptr);
-	} else {
-		find_zone_and_free(ptr, false);
-	}
-}
-
-// We have this function so code within libmalloc can call it without going
-// through the (potentially interposed) dyld symbol stub
-static void *
-_realloc(void *in_ptr, size_t new_size)
+realloc(void *in_ptr, size_t new_size)
 {
 	void *retval = NULL;
 	void *old_ptr;
@@ -2528,9 +1947,9 @@
 	// size."  So we only free the original memory if the allocation succeeds.
 	old_ptr = (new_size == 0) ? NULL : in_ptr;
 	if (!old_ptr) {
-		retval = _malloc_zone_malloc(default_zone, new_size, MZ_NONE);
+		retval = malloc_zone_malloc(default_zone, new_size);
 	} else {
-		zone = find_registered_zone(old_ptr, NULL, false);
+		zone = find_registered_zone(old_ptr, NULL);
 		if (!zone) {
 			int flags = MALLOC_REPORT_DEBUG | MALLOC_REPORT_NOLOG;
 			if (malloc_debug_flags & (MALLOC_ABORT_ON_CORRUPTION | MALLOC_ABORT_ON_ERROR)) {
@@ -2538,7 +1957,7 @@
 			}
 			malloc_report(flags, "*** error for object %p: pointer being realloc'd was not allocated\n", in_ptr);
 		} else {
-			retval = _malloc_zone_realloc(zone, old_ptr, new_size);
+			retval = malloc_zone_realloc(zone, old_ptr, new_size);
 		}
 	}
 
@@ -2550,14 +1969,6 @@
 	return retval;
 }
 
-MALLOC_NOINLINE
-void *
-realloc(void *in_ptr, size_t new_size)
-{
-	return _realloc(in_ptr, new_size);
-}
-
-MALLOC_NOINLINE
 void *
 valloc(size_t size)
 {
@@ -2579,7 +1990,7 @@
 		return size;
 	}
 
-	(void)find_registered_zone(ptr, &size, false);
+	(void)find_registered_zone(ptr, &size);
 	return size;
 }
 
@@ -2606,16 +2017,14 @@
  *	There is insufficient memory available with the requested alignment.
  */
 
-// We have this function so code within libmalloc can call it without going
-// through the (potentially interposed) dyld symbol stub
-static int
-_posix_memalign(void **memptr, size_t alignment, size_t size)
+int
+posix_memalign(void **memptr, size_t alignment, size_t size)
 {
 	void *retval;
 
 	/* POSIX is silent on NULL == memptr !?! */
 
-	retval = _malloc_zone_memalign(default_zone, alignment, size, MZ_NONE);
+	retval = malloc_zone_memalign(default_zone, alignment, size);
 	if (retval == NULL) {
 		// To avoid testing the alignment constraints redundantly, we'll rely on the
 		// test made in malloc_zone_memalign to vet each request. Only if that test fails
@@ -2632,13 +2041,6 @@
 	}
 }
 
-MALLOC_NOINLINE
-int
-posix_memalign(void **memptr, size_t alignment, size_t size)
-{
-	return _posix_memalign(memptr, alignment, size);
-}
-
 boolean_t
 malloc_claimed_address(void *ptr)
 {
@@ -2700,476 +2102,6 @@
 	return reallocf(in_ptr, alloc_size);
 }
 
-/*********	malloc_type	************/
-
-#if MALLOC_TARGET_64BIT
-
-MALLOC_ALWAYS_INLINE MALLOC_INLINE
-static malloc_type_descriptor_t
-_malloc_type_outlined_set_tsd(malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = malloc_get_tsd_type_descriptor();
-
-	if (!type_id) {
-		// We need this to be non-zero so that we can use it for the recursion
-		// check below
-		type_id = MALLOC_TYPE_ID_NONZERO;
-	}
-	malloc_set_tsd_type_descriptor(
-			(malloc_type_descriptor_t){ .type_id = type_id });
-
-	return prev_type_desc;
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_malloc_outlined(size_t size, malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = malloc(size);
-	} else {
-		ptr = _malloc_zone_malloc(default_zone, size, MZ_POSIX);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_calloc_outlined(size_t count, size_t size, malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = calloc(count, size);
-	} else {
-		ptr = _malloc_zone_calloc(default_zone, count, size, MZ_POSIX);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-// TODO: malloc_type_free_outlined
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_realloc_outlined(void *ptr, size_t size, malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *new_ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		new_ptr = realloc(ptr, size);
-	} else {
-		new_ptr = _realloc(ptr, size);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return new_ptr;
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_aligned_alloc_outlined(size_t alignment, size_t size,
-		malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = aligned_alloc(alignment, size);
-	} else {
-		ptr = _malloc_zone_memalign(default_zone, alignment, size,
-			MZ_POSIX | MZ_C11);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-MALLOC_NOINLINE
-static int
-_malloc_type_posix_memalign_outlined(void **memptr, size_t alignment,
-		size_t size, malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	int retval;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		retval = posix_memalign(memptr, alignment, size);
-	} else {
-		retval = _posix_memalign(memptr, alignment, size);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return retval;
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_zone_malloc_outlined(malloc_zone_t *zone, size_t size,
-		malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = malloc_zone_malloc(zone, size);
-	} else {
-		ptr = _malloc_zone_malloc(zone, size, MZ_NONE);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_zone_calloc_outlined(malloc_zone_t *zone, size_t count, size_t size,
-		malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = malloc_zone_calloc(zone, count, size);
-	} else {
-		ptr = _malloc_zone_calloc(zone, count, size, MZ_NONE);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-// TODO: malloc_type_zone_free_outlined
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_zone_realloc_outlined(malloc_zone_t *zone, void *ptr, size_t size,
-		malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *new_ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		new_ptr = malloc_zone_realloc(zone, ptr, size);
-	} else {
-		new_ptr = _malloc_zone_realloc(zone, ptr, size);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return new_ptr;
-}
-
-MALLOC_NOINLINE
-static void *
-_malloc_type_zone_memalign_outlined(malloc_zone_t *zone, size_t alignment,
-		size_t size, malloc_type_id_t type_id)
-{
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = malloc_zone_memalign(zone, alignment, size);
-	} else {
-		ptr = _malloc_zone_memalign(zone, alignment, size, MZ_NONE);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-void *
-malloc_type_malloc(size_t size, malloc_type_id_t type_id)
-{
-	if (os_unlikely(size > malloc_absolute_max_size)) {
-		malloc_set_errno_fast(MZ_POSIX, ENOMEM);
-		return NULL;
-	}
-
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_malloc_outlined(size, type_id);
-	}
-
-	malloc_zone_t *zone0 = malloc_zones[0];
-
-
-	if (zone0->version >= 13) {
-		return zone0->malloc(zone0, size);
-	}
-
-	return _malloc_type_malloc_outlined(size, type_id);
-}
-
-void *
-malloc_type_calloc(size_t count, size_t size, malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_calloc_outlined(count, size, type_id);
-	}
-
-	malloc_zone_t *zone0 = malloc_zones[0];
-
-	if (zone0->version >= 13) {
-		return zone0->calloc(zone0, count, size);
-	}
-
-	return _malloc_type_calloc_outlined(count, size, type_id);
-}
-
-void
-malloc_type_free(void *ptr, malloc_type_id_t type_id)
-{
-	// TODO: this is not interposition-safe - need to revist when we want to
-	// actually start using this
-	return free(ptr);
-}
-
-void *
-malloc_type_realloc(void *ptr, size_t size, malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_realloc_outlined(ptr, size, type_id);
-	}
-
-	malloc_zone_t *zone0 = malloc_zones[0];
-
-	// We're okay with dropping the type information here because
-	// malloc_slowpath should cover most of the situations we'd want to preserve
-	// it for.  If we'd prefer to get more coverage we could go through
-	// _malloc_type_realloc_outlined(), at the expense of doing the TSD
-	// save/restore pointlessly sometimes.
-	return _realloc(ptr, size);
-}
-
-void *
-malloc_type_valloc(size_t size, malloc_type_id_t type_id)
-{
-	// valloc is not used often enough to warrant fastpath handling, so we'll
-	// just always pass the type information via the TSD
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = valloc(size);
-	} else {
-		ptr = _malloc_zone_valloc(default_zone, size, MZ_POSIX);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-void *
-malloc_type_aligned_alloc(size_t alignment, size_t size,
-		malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_aligned_alloc_outlined(alignment, size, type_id);
-	}
-
-
-	// Everything else takes the slower path
-	return _malloc_type_aligned_alloc_outlined(alignment, size, type_id);
-}
-
-int
-malloc_type_posix_memalign(void **memptr, size_t alignment, size_t size,
-		malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_posix_memalign_outlined(memptr, alignment, size,
-				type_id);
-	}
-
-
-	return _malloc_type_posix_memalign_outlined(memptr, alignment, size,
-			type_id);
-}
-
-void *
-malloc_type_zone_malloc(malloc_zone_t *zone, size_t size,
-		malloc_type_id_t type_id)
-{
-	if (os_unlikely(size > malloc_absolute_max_size)) {
-		malloc_set_errno_fast(MZ_POSIX, ENOMEM);
-		return NULL;
-	}
-
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_zone_malloc_outlined(zone, size, type_id);
-	}
-
-	if (zone == default_zone) {
-		zone = malloc_zones[0];
-	}
-
-
-	if (zone->version >= 13) {
-		return zone->malloc(zone, size);
-	}
-
-	return _malloc_type_zone_malloc_outlined(zone, size, type_id);
-}
-
-void *
-malloc_type_zone_calloc(malloc_zone_t *zone, size_t count, size_t size,
-		malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_zone_calloc_outlined(zone, count, size, type_id);
-	}
-
-	if (zone == default_zone) {
-		zone = malloc_zones[0];
-	}
-
-
-	if (zone->version >= 13) {
-		return zone->calloc(zone, count, size);
-	}
-
-	return _malloc_type_zone_calloc_outlined(zone, count, size, type_id);
-}
-
-void
-malloc_type_zone_free(malloc_zone_t *zone, void *ptr, malloc_type_id_t type_id)
-{
-	// TODO: this is not interposition-safe - need to revist when we want to
-	// actually start using this
-	return malloc_zone_free(zone, ptr);
-}
-
-void *
-malloc_type_zone_realloc(malloc_zone_t *zone, void *ptr, size_t size,
-		malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_zone_realloc_outlined(zone, ptr, size, type_id);
-	}
-
-	if (zone == default_zone) {
-		zone = malloc_zones[0];
-	}
-
-
-	// We're okay with dropping the type information here because
-	// malloc_slowpath should cover most of the situations we'd want to preserve
-	// it for.  If we'd prefer to get more coverage we could go through
-	// _malloc_type_zone_realloc_outlined(), at the expense of doing the TSD
-	// save/restore pointlessly sometimes.
-	return _malloc_zone_realloc(zone, ptr, size);
-}
-
-void *
-malloc_type_zone_valloc(malloc_zone_t *zone, size_t size,
-		malloc_type_id_t type_id)
-{
-	// valloc is not used often enough to warrant fastpath handling, so we'll
-	// just always pass the type information via the TSD
-	malloc_type_descriptor_t prev_type_desc = _malloc_type_outlined_set_tsd(
-			type_id);
-
-	void *ptr;
-	if (malloc_interposition_compat && !prev_type_desc.type_id) {
-		// We're (potentially) interposed at the symbol level and aren't in a
-		// recursive call, so call through the external symbol
-		ptr = malloc_zone_valloc(zone, size);
-	} else {
-		ptr = _malloc_zone_valloc(zone, size, MZ_NONE);
-	}
-
-	malloc_set_tsd_type_descriptor(prev_type_desc);
-	return ptr;
-}
-
-void *
-malloc_type_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size,
-		malloc_type_id_t type_id)
-{
-	if (os_unlikely(malloc_logger || malloc_slowpath)) {
-		return _malloc_type_zone_memalign_outlined(zone, alignment, size,
-				type_id);
-	}
-
-
-	// Everything else takes the slower path
-	return _malloc_type_zone_memalign_outlined(zone, alignment, size, type_id);
-}
-
-#endif // MALLOC_TARGET_64BIT
-
-/*********	Purgeable zone	************/
-
-static void
-_malloc_create_purgeable_zone(void * __unused ctx)
-{
-	//
-	// PR_7288598: Must pass a *scalable* zone (szone) as the helper for create_purgeable_zone().
-	// Take care that the zone so obtained is not subject to interposing.
-	//
-	if (!initial_scalable_zone) {
-		// If the process didn't initially create a scalable zone because xzone
-		// malloc is enabled, we should create one now.
-		//
-		// TODO: xzone-backed purgeable zone
-		initial_scalable_zone = create_scalable_zone(0, malloc_debug_flags);
-		malloc_set_zone_name(initial_scalable_zone,
-				DEFAULT_SCALABLE_ZONE_STRING);
-		malloc_zone_register(initial_scalable_zone);
-	}
-
-	default_purgeable_zone = create_purgeable_zone(0, initial_scalable_zone,
-			malloc_debug_flags);
-	malloc_zone_register(default_purgeable_zone);
-	malloc_set_zone_name(default_purgeable_zone,
-			DEFAULT_PUREGEABLE_ZONE_STRING);
-}
-
-malloc_zone_t *
-malloc_default_purgeable_zone(void)
-{
-	static os_once_t pred;
-	os_once(&pred, NULL, _malloc_create_purgeable_zone);
-	return default_purgeable_zone;
-}
-
 static malloc_zone_t *
 find_registered_purgeable_zone(void *ptr)
 {
@@ -3184,7 +2116,7 @@
 	 * and only search those.
 	 */
 	size_t size = 0;
-	malloc_zone_t *zone = find_registered_zone(ptr, &size, false);
+	malloc_zone_t *zone = find_registered_zone(ptr, &size);
 
 	/* FIXME: would really like a zone->introspect->flags->purgeable check, but haven't determined
 	 * binary compatibility impact of changing the introspect struct yet. */
@@ -3233,34 +2165,32 @@
 	return 0;
 }
 
-/*********	Memory events	************/
-
 void
 malloc_enter_process_memory_limit_warn_mode(void)
 {
 	// <rdar://problem/25063714>
 }
 
+
+
 // Note that malloc_memory_event_handler is not thread-safe, and we are relying on the callers of this for synchronization
 void
 malloc_memory_event_handler(unsigned long event)
 {
-#if CONFIG_MADVISE_PRESSURE_RELIEF || (CONFIG_LARGE_CACHE && !CONFIG_DEFERRED_RECLAIM)
-	if (event & MALLOC_MEMORYSTATUS_MASK_PRESSURE_RELIEF) {
+	if (event & NOTE_MEMORYSTATUS_PRESSURE_WARN) {
 		malloc_zone_pressure_relief(0, 0);
 	}
-#endif /* CONFIG_MADVISE_PRESSURE_RELIEF || (CONFIG_LARGE_CACHE && !CONFIG_DEFERRED_RECLAIM) */
 
 	if ((event & NOTE_MEMORYSTATUS_MSL_STATUS) != 0 && (event & ~NOTE_MEMORYSTATUS_MSL_STATUS) == 0) {
 		malloc_register_stack_logger();
 	}
 
 #if ENABLE_MEMORY_RESOURCE_EXCEPTION_HANDLING
-	if (event & MALLOC_MEMORYSTATUS_MASK_RESOURCE_EXCEPTION_HANDLING) {
+	if (event & (NOTE_MEMORYSTATUS_PROC_LIMIT_WARN | NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL | NOTE_MEMORYSTATUS_PRESSURE_CRITICAL)) {
 		malloc_register_stack_logger();
 	}
-#endif /* ENABLE_MEMORY_RESOURCE_EXCEPTION_HANDLING */
-
+#endif // ENABLE_MEMORY_RESOURCE_EXCEPTION_HANDLING
+	
 	if (msl.handle_memory_event) {
 		// Let MSL see the event.
 		msl.handle_memory_event(event);
@@ -3357,85 +2287,6 @@
 	}
 }
 
-/*********  Functions for sanitization ************/
-
-#if TARGET_OS_OSX
-
-// Shadow memory helpers
-#define SHADOW_MEMORY_BASE (0x0000200000000000ull)
-#define SHADOW_GRANULARITY_BITS 3u
-#define SHADOW_GRANULARITY (1u << SHADOW_GRANULARITY_BITS)
-#define PTR_TO_SHADOW(p) (void *)((((uintptr_t)ptr) >> SHADOW_GRANULARITY_BITS) + SHADOW_MEMORY_BASE)
-#define SIZE_TO_SHADOW_SIZE(p) ((p) >> SHADOW_GRANULARITY_BITS)
-#define SHADOW_POISON_HEAP_LEFT_RZ 0xfa
-#define SHADOW_POISON_HEAP_RIGHT_RZ 0xfb
-#define SHADOW_POISON_HEAP_FREED 0xfd
-
-static void
-malloc_sanitizer_fallback_allocate_poison(uintptr_t ptr, size_t leftrz_sz, size_t alloc_sz, size_t rightrz_sz)
-{
-	uintptr_t alloc_ptr, rightrz_ptr;
-	MALLOC_ASSERT(!os_add_overflow(ptr, leftrz_sz, &alloc_ptr) &&
-				  !os_add_overflow(alloc_ptr, alloc_sz, &rightrz_ptr));
-
-	// Tag the ASan shadow as ASAN_POISON_USER/ASAN_VALID/ASAN_POISON_USER
-	if (sanitizer_fallback_ptrs.memory_poison && sanitizer_fallback_ptrs.memory_unpoison) {
-		(*sanitizer_fallback_ptrs.memory_poison)(ptr, leftrz_sz);
-		(*sanitizer_fallback_ptrs.memory_unpoison)(alloc_ptr, alloc_sz);
-		(*sanitizer_fallback_ptrs.memory_poison)(rightrz_ptr, rightrz_sz);
-	} else {
-		// This code should only be executed by Rosetta on macOS
-		MALLOC_ASSERT(!(leftrz_sz % SHADOW_GRANULARITY) &&
-					  !((alloc_sz + rightrz_sz) % SHADOW_GRANULARITY));
-
-		const uint8_t partial = alloc_sz & (SHADOW_GRANULARITY - 1);
-		// Partial poison is not supported, leave it unpoisoned
-		const size_t left = SIZE_TO_SHADOW_SIZE(leftrz_sz),
-					right = SIZE_TO_SHADOW_SIZE(rightrz_sz),
-					alloc = SIZE_TO_SHADOW_SIZE(alloc_sz) + !!partial;
-		uint8_t *shadow = PTR_TO_SHADOW(ptr);
-		memset(shadow, SHADOW_POISON_HEAP_LEFT_RZ, left);
-		shadow += left;
-		bzero(shadow + left, alloc);
-		shadow += alloc;
-		memset(shadow, SHADOW_POISON_HEAP_RIGHT_RZ, right);
-	}
-}
-
-static void
-malloc_sanitizer_fallback_deallocate_poison(uintptr_t ptr, size_t sz)
-{
-	// Tag the ASan shadow as ASAN_POISON_USER
-	if (sanitizer_fallback_ptrs.memory_poison) {
-		(*sanitizer_fallback_ptrs.memory_poison)(ptr, sz);
-	} else {
-		memset(PTR_TO_SHADOW(ptr), SHADOW_POISON_HEAP_FREED, SIZE_TO_SHADOW_SIZE(sz));
-	}
-}
-
-#endif // TARGET_OS_OSX
-
-bool malloc_sanitizer_is_enabled(void)
-{
-	return malloc_sanitizer_enabled;
-}
-
-const struct malloc_sanitizer_poison *
-malloc_sanitizer_get_functions(void)
-{
-#if TARGET_OS_OSX
-	return sanitizer ? sanitizer : &sanitizer_fallback;
-#else
-	return sanitizer;
-#endif
-}
-
-void
-malloc_sanitizer_set_functions(struct malloc_sanitizer_poison *s)
-{
-	sanitizer = s;
-}
-
 /*********	Functions for performance tools	************/
 
 kern_return_t
@@ -3604,9 +2455,6 @@
 {
 	unsigned index = 0;
 	MALLOC_LOCK();
-#if CONFIG_EARLY_MALLOC
-	mfm_lock();
-#endif
 	while (index < malloc_num_zones) {
 		malloc_zone_t *zone = malloc_zones[index++];
 		zone->introspect->force_lock(zone);
@@ -3627,9 +2475,6 @@
 		malloc_zone_t *zone = malloc_zones[index++];
 		zone->introspect->force_unlock(zone);
 	}
-#if CONFIG_EARLY_MALLOC
-	mfm_unlock();
-#endif
 	MALLOC_UNLOCK();
 }
 
@@ -3648,9 +2493,6 @@
 			zone->introspect->reinit_lock(zone);
 		}
 	}
-#if CONFIG_EARLY_MALLOC
-	mfm_reinit_lock();
-#endif
 	MALLOC_REINIT_LOCK();
 }
 
@@ -3679,6 +2521,8 @@
 	if (_malloc_entropy_initialized) {
 		if (_malloc_engaged_nano == NANO_V2) {
 			nanov2_forked_zone((nanozonev2_t *)initial_nano_zone);
+		} else if (_malloc_engaged_nano == NANO_V1) {
+			nano_forked_zone((nanozone_t *)initial_nano_zone);
 		}
 	}
 #endif
@@ -3776,17 +2620,7 @@
 	}
 }
 
-void
-malloc_zero_on_free_disable(void)
-{
-	malloc_zero_policy = MALLOC_ZERO_NONE;
-}
-
 /*****************	OBSOLETE ENTRY POINTS	********************/
-
-#ifndef PHASE_OUT_OLD_MALLOC
-#define PHASE_OUT_OLD_MALLOC 0
-#endif
 
 #if PHASE_OUT_OLD_MALLOC
 #error PHASE OUT THE FOLLOWING FUNCTIONS
@@ -3822,41 +2656,8 @@
 }
 
 #pragma mark -
-#pragma mark Malloc Thread Options
-
-typedef union {
-	malloc_thread_options_t options;
-	void *storage;
-} th_opts_t;
-
-MALLOC_STATIC_ASSERT(sizeof(th_opts_t) == sizeof(void *), "Options fit into pointer bits");
-
-malloc_thread_options_t
-malloc_get_thread_options(void)
-{
-	th_opts_t x = {.storage = _pthread_getspecific_direct(__TSD_MALLOC_THREAD_OPTIONS)};
-	return x.options;
-}
-
-void
-malloc_set_thread_options(malloc_thread_options_t opts)
-{
-	// Canonicalize options
-	if (opts.DisableExpensiveDebuggingOptions) {
-		opts.DisableProbabilisticGuardMalloc = true;
-		opts.DisableMallocStackLogging = true;
-	}
-
-	pgm_thread_set_disabled(opts.DisableProbabilisticGuardMalloc);
-
-	th_opts_t x = {.options = opts};
-	_pthread_setspecific_direct(__TSD_MALLOC_THREAD_OPTIONS, x.storage);
-}
-
-#pragma mark -
 #pragma mark Malloc Stack Logging
 
-static bool _malloc_register_stack_logger(bool at_startup);
 
 /* this is called from libsystem during initialization. */
 static void
@@ -3866,21 +2667,23 @@
 	_dlopen = funcs->dlopen;
 	_dlsym = funcs->dlsym;
 #endif
-	if (funcs->version >= 2 && funcs->msl) {
-		msl = *funcs->msl;
-	}
 	const char **env = (const char**) *_NSGetEnviron();
 	for (const char **e = env; *e; e++) {
 		if (0==strncmp(*e, "MallocStackLogging", 18)) {
-			_malloc_register_stack_logger(true);
-			if (msl.set_flags_from_environment) {
-				msl.set_flags_from_environment(env);
+			malloc_register_stack_logger();
+			void (*msl_set_flags_from_environment) (const char **env);
+			msl_set_flags_from_environment = _dlsym(msl.dylib, "msl_set_flags_from_environment");
+			if (msl_set_flags_from_environment) {
+				msl_set_flags_from_environment(env);
 			}
 			break;
 		}
 	}
-	if (msl.initialize) {
-		msl.initialize();
+	if (msl.dylib) {
+		void (*initialize) () = _dlsym(msl.dylib, "msl_initialize");
+		if (initialize) {
+			initialize();
+		}
 	}
 }
 
@@ -3890,70 +2693,45 @@
 static void
 register_msl_dylib(void *dylib)
 {
-#if TARGET_OS_DRIVERKIT
-	set_msl_lite_hooks(msl.copy_msl_lite_hooks);
-#else
 	if (!dylib) {
 		return;
 	}
-	msld.dylib = dylib;
+	msl.dylib = dylib;
 	msl.handle_memory_event = _dlsym(dylib, "msl_handle_memory_event");
 	msl.stack_logging_locked = _dlsym(dylib, "msl_stack_logging_locked");
 	msl.fork_prepare = _dlsym(dylib, "msl_fork_prepare");
 	msl.fork_child = _dlsym(dylib, "msl_fork_child");
 	msl.fork_parent = _dlsym(dylib, "msl_fork_parent");
-	msl.turn_on_stack_logging = _dlsym(dylib, "msl_turn_on_stack_logging");
-	msl.turn_off_stack_logging = _dlsym(dylib, "msl_turn_off_stack_logging");
-	msl.set_flags_from_environment = _dlsym(dylib, "msl_set_flags_from_environment");
-	msl.initialize = _dlsym(dylib, "msl_initialize");
-
 	
 	// TODO delete these ones
-	msld.get_frames_for_address = _dlsym(dylib, "msl_get_frames_for_address");
-	msld.stackid_for_vm_region = _dlsym(dylib, "msl_stackid_for_vm_region");
-	msld.get_frames_for_stackid = _dlsym(dylib, "msl_get_frames_for_stackid");
-	msld.uniquing_table_read_stack = _dlsym(dylib, "msl_uniquing_table_read_stack");
+	msl.get_frames_for_address = _dlsym(dylib, "msl_get_frames_for_address");
+	msl.stackid_for_vm_region = _dlsym(dylib, "msl_stackid_for_vm_region");
+	msl.get_frames_for_stackid = _dlsym(dylib, "msl_get_frames_for_stackid");
+	msl.uniquing_table_read_stack = _dlsym(dylib, "msl_uniquing_table_read_stack");
 
 	void (*msl_copy_msl_lite_hooks) (struct _malloc_msl_lite_hooks_s *hooksp, size_t size);
 	msl_copy_msl_lite_hooks = _dlsym(dylib, "msl_copy_msl_lite_hooks");
 	if (msl_copy_msl_lite_hooks) {
 		set_msl_lite_hooks(msl_copy_msl_lite_hooks);
 	}
-#endif
 }
 
 MALLOC_EXPORT
 boolean_t
 malloc_register_stack_logger(void)
 {
-    return _malloc_register_stack_logger(false);
-}
-
-static bool
-_malloc_register_stack_logger(bool at_startup)
-{
-	void *dylib = NULL;
-	if (malloc_sanitizer_enabled && !at_startup) {
-		return false;
-	}
-#if !TARGET_OS_DRIVERKIT
-	if (msl.handle_memory_event != NULL) {
+	if (msl.dylib != NULL) {
 		return true;
 	}
-	if (_dlopen == NULL) {
-		return false;
-	}
-	dylib = _dlopen("/System/Library/PrivateFrameworks/MallocStackLogging.framework/MallocStackLogging", RTLD_GLOBAL);
+	void *dylib = _dlopen("/System/Library/PrivateFrameworks/MallocStackLogging.framework/MallocStackLogging", RTLD_GLOBAL);
 	if (dylib == NULL) {
 		return false;	
 	}
-#endif
 	os_once(&_register_msl_dylib_pred, dylib, register_msl_dylib);
-	if (!msl.handle_memory_event) {
+	if (!msl.dylib) {
 		malloc_report(ASL_LEVEL_WARNING, "failed to load MallocStackLogging.framework\n");
-		return false;
-	}
-	return true;
+	}
+	return msl.dylib == dylib;
 }
 
 /* Symbolication.framework looks up this symbol by name inside libsystem_malloc.dylib. */
@@ -3975,48 +2753,55 @@
 turn_on_stack_logging(stack_logging_mode_type mode)
 {
 	malloc_register_stack_logger();
-	if (!msl.turn_on_stack_logging) {
+	if (!msl.dylib) {
 		return false;
 	}
-	return msl.turn_on_stack_logging(mode);
+	boolean_t (*msl_turn_on_stack_logging) (stack_logging_mode_type mode);
+	msl_turn_on_stack_logging = _dlsym(msl.dylib, "msl_turn_on_stack_logging");
+	if (!msl_turn_on_stack_logging) {
+		return false;
+	}
+	return msl_turn_on_stack_logging(mode);
 }
 
 MALLOC_EXPORT
 void turn_off_stack_logging(void)
 {
 	malloc_register_stack_logger();
-	if (msl.turn_off_stack_logging) {
-		msl.turn_off_stack_logging();
-	}
-}
-
-//deprecated
+	if (!msl.dylib) {
+		return;
+	}
+	void (*msl_turn_off_stack_logging) ();
+	msl_turn_off_stack_logging = _dlsym(msl.dylib, "msl_turn_off_stack_logging");
+	if (msl_turn_off_stack_logging) {
+		msl_turn_off_stack_logging();
+	}
+}
+
 kern_return_t
 __mach_stack_logging_start_reading(task_t task, vm_address_t shared_memory_address, boolean_t *uses_lite_mode)
 {
 	malloc_register_stack_logger();
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return KERN_FAILURE;
 	}
 	kern_return_t (*f) (task_t task, vm_address_t shared_memory_address, boolean_t *uses_lite_mode);
-	f = _dlsym(msld.dylib, "msl_start_reading");
+	f = _dlsym(msl.dylib, "msl_start_reading");
 	if (!f) {
 		return KERN_FAILURE;
 	}
 	return f(task, shared_memory_address, uses_lite_mode);
 }
 
-
-//deprecated
 kern_return_t
 __mach_stack_logging_stop_reading(task_t task)
 {
 	malloc_register_stack_logger();
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return KERN_FAILURE;
 	}
 	kern_return_t (*f) (task_t task);
-	f = _dlsym(msld.dylib, "msl_stop_reading");
+	f = _dlsym(msl.dylib, "msl_stop_reading");
 	if (!f) {
 		return KERN_FAILURE;
 	}
@@ -4031,23 +2816,23 @@
 								uint32_t *count)
 {
 	malloc_register_stack_logger();
-	if (!msld.get_frames_for_address) {
+	if (!msl.get_frames_for_address) {
 		return KERN_FAILURE;
 	}
-	return msld.get_frames_for_address(task, address, stack_frames_buffer, max_stack_frames, count);
+	return msl.get_frames_for_address(task, address, stack_frames_buffer, max_stack_frames, count);
 }
 
 uint64_t
 __mach_stack_logging_stackid_for_vm_region(task_t task, mach_vm_address_t address)
 {
 	malloc_register_stack_logger();
-	if (!msld.stackid_for_vm_region) {
+	if (!msl.stackid_for_vm_region) {
 		return -1ull;
 	}
-	return msld.stackid_for_vm_region(task, address);
-}
-
-//deprecated
+	return msl.stackid_for_vm_region(task, address);
+}
+
+
 kern_return_t
 __mach_stack_logging_frames_for_uniqued_stack(task_t task,
 											  uint64_t stack_identifier,
@@ -4056,13 +2841,12 @@
 											  uint32_t *count)
 {
 	malloc_register_stack_logger();
-	if (!msld.get_frames_for_stackid) {
+	if (!msl.get_frames_for_stackid) {
 		return KERN_FAILURE;
 	}
-	return msld.get_frames_for_stackid(task, stack_identifier, stack_frames_buffer, max_stack_frames, count, NULL);
-}
-
-//deprecated
+	return msl.get_frames_for_stackid(task, stack_identifier, stack_frames_buffer, max_stack_frames, count, NULL);
+}
+
 kern_return_t
 __mach_stack_logging_get_frames_for_stackid(task_t task,
 											uint64_t stack_identifier,
@@ -4072,13 +2856,12 @@
 											bool *last_frame_is_threadid)
 {
 	malloc_register_stack_logger();
-	if (!msld.get_frames_for_stackid) {
+	if (!msl.get_frames_for_stackid) {
 		return KERN_FAILURE;
 	}
-	return msld.get_frames_for_stackid(task, stack_identifier, stack_frames_buffer, max_stack_frames, count, last_frame_is_threadid);
-}
-
-//deprecated
+	return msl.get_frames_for_stackid(task, stack_identifier, stack_frames_buffer, max_stack_frames, count, last_frame_is_threadid);
+}
+
 kern_return_t
 __mach_stack_logging_uniquing_table_read_stack(struct backtrace_uniquing_table *uniquing_table,
 											   uint64_t stackid,
@@ -4087,13 +2870,12 @@
 											   uint32_t max_frames)
 {
 	malloc_register_stack_logger();
-	if (!msld.uniquing_table_read_stack) {
+	if (!msl.uniquing_table_read_stack) {
 		return KERN_FAILURE;
 	}
-	return msld.uniquing_table_read_stack(uniquing_table, stackid, out_frames_buffer, out_frames_count, max_frames);
-}
-
-//deprecated
+	return msl.uniquing_table_read_stack(uniquing_table, stackid, out_frames_buffer, out_frames_count, max_frames);
+}
+
 kern_return_t
 __mach_stack_logging_enumerate_records(task_t task,
 									   mach_vm_address_t address,
@@ -4105,100 +2887,93 @@
 						mach_vm_address_t address,
 						void enumerator(mach_stack_logging_record_t, void *),
 						void *context);
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return KERN_FAILURE;
 	}
-	f = _dlsym(msld.dylib, "msl_disk_stack_logs_enumerate_from_task");
+	f = _dlsym(msl.dylib, "msl_disk_stack_logs_enumerate_from_task");
 	if (!f) {
 		return KERN_FAILURE;
 	}
 	return f(task, address, enumerator, context);
 }
 
-
-//deprecated
 struct backtrace_uniquing_table *
 __mach_stack_logging_copy_uniquing_table(task_t task)
 {
 	malloc_register_stack_logger();
 	struct backtrace_uniquing_table * (*f) (task_t task);
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return NULL;
 	}
-	f = _dlsym(msld.dylib, "msl_uniquing_table_copy_from_task");
+	f = _dlsym(msl.dylib, "msl_uniquing_table_copy_from_task");
 	if (!f) {
 		return NULL;
 	}
 	return f(task);
 }
 
-//deprecated
 struct backtrace_uniquing_table *
 __mach_stack_logging_uniquing_table_copy_from_serialized(void *buffer, size_t size)
 {
 	malloc_register_stack_logger();
 	struct backtrace_uniquing_table * (*f) (void *buffer, size_t size);
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return NULL;
 	}
-	f = _dlsym(msld.dylib, "msl_uniquing_table_copy_from_serialized");
+	f = _dlsym(msl.dylib, "msl_uniquing_table_copy_from_serialized");
 	if (!f) {
 		return NULL;
 	}
 	return f(buffer, size);
 }
 
-//deprecated
 void
 __mach_stack_logging_uniquing_table_release(struct backtrace_uniquing_table *table)
 {
 	malloc_register_stack_logger();
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return;
 	}
 	void (*f) (struct backtrace_uniquing_table *table);
-	f = _dlsym(msld.dylib, "msl_uniquing_table_release");
+	f = _dlsym(msl.dylib, "msl_uniquing_table_release");
 	if (f) {
 		f(table);
 	}
 }
 
-//deprecated
 void
 __mach_stack_logging_uniquing_table_retain(struct backtrace_uniquing_table *table)
 {
 	malloc_register_stack_logger();
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return;
 	}
 	void (*f) (struct backtrace_uniquing_table *table);
-	f = _dlsym(msld.dylib, "msl_uniquing_table_retain");
+	f = _dlsym(msl.dylib, "msl_uniquing_table_retain");
 	if (f) {
 		f(table);
 	}
 }
 
-//deprecated
 extern
 size_t
 __mach_stack_logging_uniquing_table_sizeof(struct backtrace_uniquing_table *table)
 {
 	malloc_register_stack_logger();
 	size_t (*f) (struct backtrace_uniquing_table *table);
-	f = _dlsym(msld.dylib, "msl_uniquing_table_retain");
+	f = _dlsym(msl.dylib, "msl_uniquing_table_retain");
 	return f(table);
 }
 
-//deprecated
 void *
 __mach_stack_logging_uniquing_table_serialize(struct backtrace_uniquing_table *table, mach_vm_size_t *size)
 {
 	malloc_register_stack_logger();
-	if (!msld.dylib) {
+	if (!msl.dylib) {
 		return NULL;
 	}
 	void * (*f) (struct backtrace_uniquing_table *table, mach_vm_size_t *size);
-	f = _dlsym(msld.dylib, "msl_uniquing_table_serialize");
+	f = _dlsym(msl.dylib, "msl_uniquing_table_serialize");
 	if (!f) {
 		return NULL;
 	}