--- libmalloc/libmalloc-140.40.1/src/malloc.c
+++ libmalloc/libmalloc-425.100.7/src/malloc.c
@@ -23,47 +23,14 @@
 
 #include "internal.h"
 
-#if TARGET_OS_EMBEDDED || TARGET_IPHONE_SIMULATOR
-// _malloc_printf(ASL_LEVEL_INFO...) on iOS doesn't show up in the Xcode Console log of the device,
+#if MALLOC_TARGET_IOS
+// 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_ABSOLUTE_MAX_SIZE - There are many instances of addition to a
- * user-specified size_t, which can cause overflow (and subsequent crashes)
- * for values near SIZE_T_MAX.  Rather than add extra "if" checks everywhere
- * this occurs, it is easier to just set an absolute maximum request size,
- * and immediately return an error if the requested size exceeds this maximum.
- * Of course, values less than this absolute max can fail later if the value
- * is still too large for the available memory.  The largest value added
- * seems to be PAGE_SIZE (in the macro round_page()), so to be safe, we set
- * the maximum to be 2 * PAGE_SIZE less than SIZE_T_MAX.
- */
-#define MALLOC_ABSOLUTE_MAX_SIZE (SIZE_T_MAX - (2 * PAGE_SIZE))
+#endif // MALLOC_TARGET_IOS
 
 #define USE_SLEEP_RATHER_THAN_ABORT 0
-
-/*
-	MAX_LITE_MALLOCS
- 
-	If msl lite is turned on due to a memory resource exception use this value as the maximum
-	number of allocations allowed before msl lite is turned off. This prevents msl lite from being
-	enabled indefinitely if the process never reaches 100% of its jetsam limit.
-	See rdar://problem/25950426 for a discussion of how this number was determined.
- */
-
-#define MAX_LITE_MALLOCS 100000000
-
-typedef void(malloc_logger_t)(uint32_t type,
-		uintptr_t arg1,
-		uintptr_t arg2,
-		uintptr_t arg3,
-		uintptr_t result,
-		uint32_t num_hot_frames_to_skip);
-
-extern malloc_logger_t *__syscall_logger; // use this to set up syscall logging (e.g., vm_allocate, vm_deallocate, mmap, munmap)
 
 static _malloc_lock_s _malloc_lock = _MALLOC_LOCK_INIT;
 #define MALLOC_LOCK() _malloc_lock_lock(&_malloc_lock)
@@ -80,32 +47,63 @@
  */
 int32_t malloc_num_zones = 0;
 int32_t malloc_num_zones_allocated = 0;
-malloc_zone_t **malloc_zones = 0;
+malloc_zone_t **malloc_zones = (malloc_zone_t **)0xdeaddeaddeaddead;
 malloc_logger_t *malloc_logger = NULL;
-static malloc_zone_t *initial_default_zone = NULL;
+
+static uint32_t initial_num_zones;
+static malloc_zone_t *initial_scalable_zone;
+static malloc_zone_t *initial_nano_zone;
+static bool has_injected_zone0;
 
 unsigned malloc_debug_flags = 0;
-boolean_t malloc_tracing_enabled = false;
+bool malloc_tracing_enabled = false;
+bool malloc_space_efficient_enabled = false;
+bool malloc_medium_space_efficient_enabled = true;
+
+bool malloc_quarantine_enabled = false;
 
 unsigned malloc_check_start = 0; // 0 means don't check
 unsigned malloc_check_counter = 0;
 unsigned malloc_check_each = 1000;
 
-/* global flag to suppress ASL logging e.g. for syslogd */
-int _malloc_no_asl_log = 0;
-
 static int malloc_check_sleep = 100; // default 100 second sleep
 static int malloc_check_abort = 0;   // default is to sleep, not abort
-
-static int malloc_debug_file = STDERR_FILENO;
-static os_once_t _malloc_initialize_pred;
-
-static const char Malloc_Facility[] = "com.apple.Libsystem.malloc";
-
-// Used by memory resource exceptions and enabling/disabling malloc stack logging via malloc_memory_event_handler
-static boolean_t warn_mode_entered = false;
-static boolean_t warn_mode_disable_retries = false;
-static stack_logging_mode_type msl_type_enabled_at_runtime = stack_logging_mode_none;
+static bool malloc_instrumented = false;
+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 struct _malloc_msl_symbols 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 {
+	
+	void *dylib;
+
+	kern_return_t (*get_frames_for_address)(task_t task,
+											mach_vm_address_t address,
+											mach_vm_address_t *stack_frames_buffer,
+											uint32_t max_stack_frames,
+											uint32_t *count);
+	
+	uint64_t (*stackid_for_vm_region) (task_t task, mach_vm_address_t address);
+	
+	kern_return_t (*get_frames_for_stackid) (task_t task,
+											 uint64_t stack_identifier,
+											 mach_vm_address_t *stack_frames_buffer,
+											 uint32_t max_stack_frames,
+											 uint32_t *count,
+											 bool *last_frame_is_threadid);
+	
+	
+	kern_return_t (*uniquing_table_read_stack) (struct backtrace_uniquing_table *uniquing_table,
+												uint64_t stackid,
+												mach_vm_address_t *out_frames_buffer,
+												uint32_t *out_frames_count,
+												uint32_t max_frames);
+} msld = {};
 
 /*
  * Counters that coordinate zone destruction (in malloc_zone_unregister) with
@@ -115,6 +113,8 @@
 static int32_t volatile * volatile pFRZCounterLive = &counterAlice;
 static int32_t volatile * volatile pFRZCounterDrain = &counterBob;
 
+unsigned int _os_cpu_number_override = -1;
+
 static inline malloc_zone_t *inline_malloc_default_zone(void) __attribute__((always_inline));
 
 #define MALLOC_LOG_TYPE_ALLOCATE stack_logging_type_alloc
@@ -124,13 +124,62 @@
 
 #define DEFAULT_MALLOC_ZONE_STRING "DefaultMallocZone"
 #define DEFAULT_PUREGEABLE_ZONE_STRING "DefaultPurgeableMallocZone"
-
-boolean_t malloc_engaged_nano(void);
+#define MALLOC_HELPER_ZONE_STRING "MallocHelperZone"
+
+MALLOC_NOEXPORT
+unsigned int phys_ncpus;
+
+MALLOC_NOEXPORT
+unsigned int logical_ncpus;
+
+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	************/
 static bool _malloc_entropy_initialized;
 
+#if !TARGET_OS_DRIVERKIT
+#include <dlfcn.h>
+
+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;
+#else
+#define _dlopen(...) NULL
+#define _dlsym(...) NULL
+#endif // TARGET_OS_DRIVERKIT
+
 void __malloc_init(const char *apple[]);
+static void _malloc_initialize(const char *apple[], const char *bootargs);
 
 static int
 __entropy_from_kernel(const char *str)
@@ -162,17 +211,206 @@
 	return idx;
 }
 
-/* TODO: Investigate adding _malloc_initialize() into this libSystem initializer */
+#if TARGET_OS_OSX && defined(__x86_64__)
+static uint64_t
+__is_translated(void)
+{
+	return (*(uint64_t*)_COMM_PAGE_CPU_CAPABILITIES64) & kIsTranslated;
+}
+#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)
+{
+	uint64_t experiment_factors = 0;
+	str = strchr(str, '=');
+	if (str) {
+		experiment_factors = strtoull_l(str + 1, NULL, 16, NULL);
+	}
+	switch (experiment_factors) {
+	case LIBMALLOC_EXPERIMENT_DISABLE_MEDIUM:
+		magazine_medium_enabled = false;
+		break;
+	}
+}
+
+static void
+__malloc_init_from_bootargs(const char *bootargs)
+{
+	// The maximum number of magazines can be set either via a
+	// boot argument or from the environment. Get the boot argument value
+	// here and store it. We can't bounds check it until we have phys_ncpus,
+	// which happens later in _malloc_initialize(), along with handling
+	// of the environment value setting.
+	char value_buf[256];
+	const char *flag = malloc_common_value_for_key_copy(bootargs,
+			max_magazines_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) {
+			max_magazines = (unsigned int)value;
+		} else {
+			malloc_report(ASL_LEVEL_ERR,
+						   "malloc_max_magazines must be positive - ignored.\n");
+		}
+	}
+
+	flag = malloc_common_value_for_key_copy(bootargs,
+			large_expanded_cache_threshold_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_large_expanded_cache_threshold = (unsigned int)value;
+		} else {
+			malloc_report(ASL_LEVEL_ERR,
+					"malloc_large_expanded_cache_threshold must be positive - ignored.\n");
+		}
+	}
+
+	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__)
+	if (__is_translated()) {
+		magazine_medium_active_threshold = 0;
+	}
+#elif defined(__arm64__)
+	magazine_medium_active_threshold = 0;
+#endif
+#endif /* TARGET_OS_OSX */
+
+	flag = malloc_common_value_for_key_copy(bootargs, medium_enabled_boot_arg,
+			value_buf, sizeof(value_buf));
+	if (flag) {
+		const char *endp;
+		long value = malloc_common_convert_to_long(flag, &endp);
+		if (!*endp) {
+			magazine_medium_enabled = (value != 0);
+		}
+	}
+
+	flag = malloc_common_value_for_key_copy(bootargs,
+			medium_activation_threshold_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_active_threshold = (uint64_t)value;
+		} else {
+			malloc_report(ASL_LEVEL_ERR,
+					"malloc_medium_activation_threshold must be positive - ignored.\n");
+		}
+	}
+
+	flag = malloc_common_value_for_key_copy(bootargs,
+			max_medium_magazines_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) {
+			max_medium_magazines = (int)value;
+		} else {
+			malloc_report(ASL_LEVEL_ERR,
+					"malloc_max_medium_magazines must be positive - ignored.\n");
+		}
+	}
+
+	flag = malloc_common_value_for_key_copy(bootargs,
+			medium_space_efficient_boot_arg, value_buf, sizeof(value_buf));
+	if (flag) {
+		const char *endp;
+		long value = malloc_common_convert_to_long(flag, &endp);
+		if (!*endp) {
+			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
+}
+
+extern malloc_zone_t *force_asan_init_if_present(void)
+		asm("_malloc_default_zone");
+
 void
 __malloc_init(const char *apple[])
 {
-#if CONFIG_NANOZONE
-	// TODO: envp should be passed down from Libsystem
-	const char **envp = (const char **)*_NSGetEnviron();
-	nano_init(envp, apple);
+	// We could try to be clever and cater for arbitrary length bootarg
+	// strings, but it's probably not worth it, especially as we would need
+	// to temporarily allocate at least a page of memory to read the bootargs
+	// into.
+	char bootargs[1024] = { '\0' };
+	bool allow_bootargs = true;
+#if CONFIG_FEATUREFLAGS_SIMPLE
+	allow_bootargs &= os_feature_enabled_simple(libmalloc, EnableBootArgs, false);
 #endif
+#if defined(_COMM_PAGE_DEV_FIRM)
+	allow_bootargs &= !!*((uint32_t *)_COMM_PAGE_DEV_FIRM);
+#endif // _COMM_PAGE_DEV_FIRM
+
+	size_t len = sizeof(bootargs) - 1;
+	if (allow_bootargs &&
+			!sysctlbyname("kern.bootargs", bootargs, &len, NULL, 0) &&
+			len > 0) {
+		bootargs[len + 1] = '\0';
+	}
+
+#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;
+	}
+#endif
+
+	// 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;
 
 	const char **p;
+	const char *malloc_experiments = NULL;
 	for (p = apple; p && *p; p++) {
 		if (strstr(*p, "malloc_entropy") == *p) {
 			int count = __entropy_from_kernel(*p);
@@ -181,18 +419,65 @@
 			if (sizeof(malloc_entropy) / sizeof(malloc_entropy[0]) == count) {
 				_malloc_entropy_initialized = true;
 			}
-			break;
-		}
+		}
+		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));
 		_malloc_entropy_initialized = true;
 	}
 
+	if (malloc_experiments) {
+		__malloc_init_experiments(malloc_experiments);
+	}
+	__malloc_init_from_bootargs(bootargs);
 	mvm_aslr_init();
-}
-
-static malloc_zone_t* lite_zone = NULL;
+
+	/*
+	 * This really is a renamed call to malloc_default_zone() which is
+	 * interposable and interposed by asan, so that we trigger the lazy
+	 * initialization of asan _BEFORE_ _malloc_initialize().
+	 *
+	 * If we do it after, then _malloc_initialize() then ASAN will replace
+	 * the system allocator too late and bad things happen.
+	 */
+	force_asan_init_if_present();
+
+	_malloc_initialize(apple, bootargs);
+}
+
+static void register_pgm_zone(bool internal_diagnostics);
+static void stack_logging_early_finished(const struct _malloc_late_init *funcs);
+
+// 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_QUARANTINE
+	if (malloc_quarantine_enabled) {
+		quarantine_reset_environment();
+	}
+#endif
+}
+
+MALLOC_NOEXPORT malloc_zone_t* lite_zone = NULL;
 
 MALLOC_ALWAYS_INLINE
 static inline malloc_zone_t *
@@ -292,8 +577,16 @@
 default_zone_pressure_relief(malloc_zone_t *zone, size_t goal)
 {
 	zone = runtime_default_zone();
-	
+
 	return zone->pressure_relief(zone, goal);
+}
+
+static boolean_t
+default_zone_malloc_claimed_address(malloc_zone_t *zone, void *ptr)
+{
+	zone = runtime_default_zone();
+
+	return malloc_zone_claimed_address(zone, ptr);
 }
 
 static kern_return_t
@@ -329,8 +622,8 @@
 default_zone_print(malloc_zone_t *zone, boolean_t verbose)
 {
 	zone = runtime_default_zone();
-	
-	return (void)zone->introspect->check(zone);
+
+	return (void)zone->introspect->print(zone, verbose);
 }
 
 static void
@@ -419,27 +712,25 @@
 	default_zone_batch_malloc,
 	default_zone_batch_free,
 	&default_zone_introspect,
-	9,
+	10,
 	default_zone_memalign,
 	default_zone_free_definite_size,
-	default_zone_pressure_relief
+	default_zone_pressure_relief,
+	default_zone_malloc_claimed_address,
 };
 
 static malloc_zone_t *default_zone = &virtual_default_zone.malloc_zone;
 
-static boolean_t
+MALLOC_NOEXPORT
+/*static*/ boolean_t
 has_default_zone0(void)
 {
-	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));
+	return !has_injected_zone0;
+}
+
+static inline malloc_zone_t *find_registered_zone(const void *, size_t *, bool) __attribute__((always_inline));
 static inline malloc_zone_t *
-find_registered_zone(const void *ptr, size_t *returned_size)
+find_registered_zone(const void *ptr, size_t *returned_size, bool known_non_default)
 {
 	// Returns a zone which contains ptr, else NULL
 
@@ -462,32 +753,37 @@
 			return default_zone;
 		}
 	}
-	
-	// The default zone is registered in malloc_zones[0]. There's no danger that it will ever be unregistered.
-	// So don't advance the FRZ counter yet.
-	malloc_zone_t *zone = malloc_zones[0];
-	size_t size = zone->size(zone, ptr);
-	if (size) { // Claimed by this zone?
-		if (returned_size) {
-			*returned_size = size;
-		}
-
-		// Asan and others replace the zone at position 0 with their own zone.
-		// In that case just return that zone as they need this information.
-		// Otherwise return the virtual default zone, not the actual zone in position 0.
-		if (!has_default_zone0()) {
+
+	malloc_zone_t *zone;
+	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++) {
+		zone = malloc_zones[i];
+		size = zone->size(zone, ptr);
+
+		if (size) { // Claimed by this zone?
+			if (returned_size) {
+				*returned_size = size;
+			}
+
+			// Asan and others replace the zone at position 0 with their own zone.
+			// In that case just return that zone as they need this information.
+			// Otherwise return the virtual default zone, not the actual zone in position 0.
+			if (i == 0 && has_default_zone0()) {
+				return default_zone;
+			}
+
 			return zone;
-		} else {
-			return default_zone;
 		}
 	}
 
 	int32_t volatile *pFRZCounter = pFRZCounterLive;   // Capture pointer to the counter of the moment
 	OSAtomicIncrement32Barrier(pFRZCounter); // Advance this counter -- our thread is in FRZ
 
-	unsigned index;
 	int32_t limit = *(int32_t volatile *)&malloc_num_zones;
-	malloc_zone_t **zones = &malloc_zones[1];
 
 	// From this point on, FRZ is accessing the malloc_zones[] array without locking
 	// in order to avoid contention on common operations (such as non-default-zone free()).
@@ -504,8 +800,8 @@
 	//      are still valid). It also ensures that all the pointers in the zones array are
 	//      valid until it returns, so that a stale value in limit is not dangerous.
 
-	for (index = 1; index < limit; ++index, ++zones) {
-		zone = *zones;
+	for (uint32_t i = initial_num_zones; i < limit; i++) {
+		zone = malloc_zones[i];
 		size = zone->size(zone, ptr);
 		if (size) { // Claimed by this zone?
 			goto out;
@@ -544,7 +840,7 @@
 	// lock.  If trylock succeeds, unlock it, otherwise return "locked".  Returns
 	// 0 == safe, 1 == locked/unsafe.
 
-	if (__stack_logging_locked()) {
+	if (msl.stack_logging_locked && msl.stack_logging_locked()) {
 		return 1;
 	}
 
@@ -570,8 +866,8 @@
 
 static void set_flags_from_environment(void);
 
-static void
-malloc_zone_register_while_locked(malloc_zone_t *zone)
+MALLOC_NOEXPORT void
+malloc_zone_register_while_locked(malloc_zone_t *zone, bool make_default)
 {
 	size_t protect_size;
 	unsigned i;
@@ -580,7 +876,7 @@
 	 * so, print an error message and return. */
 	for (i = 0; i != malloc_num_zones; ++i) {
 		if (zone == malloc_zones[i]) {
-			_malloc_printf(ASL_LEVEL_ERR, "Attempted to register zone more than once: %p\n", zone);
+			malloc_report(ASL_LEVEL_ERR, "Attempted to register zone more than once: %p\n", zone);
 			return;
 		}
 	}
@@ -594,7 +890,7 @@
 		vm_addr = vm_page_size;
 		kern_return_t kr = mach_vm_allocate(mach_task_self(), &vm_addr, alloc_size, alloc_flags);
 		if (kr) {
-			_malloc_printf(ASL_LEVEL_ERR, "malloc_zone_register allocation failed: %d\n", kr);
+			malloc_report(ASL_LEVEL_ERR, "malloc_zone_register allocation failed: %d\n", kr);
 			return;
 		}
 
@@ -620,6 +916,13 @@
 		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.
@@ -628,249 +931,183 @@
 	 * 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);
-	//_malloc_printf(ASL_LEVEL_INFO, "Registered malloc_zone %p in malloc_zones %p [%u zones, %u bytes]\n", zone, malloc_zones,
+
+	// 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_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);
 }
 
+// This used to be called lazyily because it is using
+// dyld_process_is_restricted() before dyld_init() has run.
+//
+// However this function is safe to use, we keep this function separate
+// if we ever need to have a 2-stage init in the future.
 static void
-create_and_insert_lite_zone_while_locked()
-{
-	malloc_zone_t *zone0 = malloc_zones[0];
+_malloc_initialize(const char *apple[], const char *bootargs)
+{
+	phys_ncpus = *(uint8_t *)(uintptr_t)_COMM_PAGE_PHYSICAL_CPUS;
+	logical_ncpus = *(uint8_t *)(uintptr_t)_COMM_PAGE_LOGICAL_CPUS;
+
+	if (0 != (logical_ncpus % phys_ncpus)) {
+		MALLOC_REPORT_FATAL_ERROR(logical_ncpus % phys_ncpus,
+				"logical_ncpus %% phys_ncpus != 0\n");
+	}
+
+	switch (logical_ncpus / phys_ncpus) {
+	case 1:
+		hyper_shift = 0;
+		break;
+	case 2:
+		hyper_shift = 1;
+		break;
+	case 4:
+		hyper_shift = 2;
+		break;
+	default:
+		MALLOC_REPORT_FATAL_ERROR(logical_ncpus / phys_ncpus, "logical_ncpus / phys_ncpus not 1, 2, or 4");
+	}
+
+	// max_magazines may already be set from a boot argument. Make sure that it
+	// is bounded by the number of CPUs.
+	if (max_magazines) {
+		max_magazines = MIN(max_magazines, logical_ncpus);
+	} else {
+		max_magazines = logical_ncpus;
+	}
+
+	// similiarly, cap medium magazines at logical_ncpus but don't cap it by
+	// the max magazines if it has been set explicitly
+	if (max_medium_magazines) {
+		max_medium_magazines = MIN(max_medium_magazines, logical_ncpus);
+	} else {
+		max_medium_magazines = max_magazines;
+	}
+
+	set_flags_from_environment(); // will only set flags up to two times
+
+	if (malloc_tracing_enabled || malloc_simple_stack_logging) {
+		// Note: although malloc_tracing_enabled is exported "for performance
+		// tools", it does not appear in any API or SPI headers and is not
+		// referenced by any indexed performance tools, so we're going to go
+		// ahead and stop respecting dynamic programmatic enablement via direct
+		// setting of the global by other code
+		//
+		// TODO: it may be possible to fold malloc_check_start into this as well
+		malloc_instrumented = true;
+	}
+
+#if CONFIG_QUARANTINE
+	malloc_quarantine_enabled = quarantine_should_enable();
+#endif
 	
-	malloc_zone_t *stack_logging_lite_zone = create_stack_logging_lite_zone(0, zone0, malloc_debug_flags);
-	malloc_zone_register_while_locked(stack_logging_lite_zone);
-	malloc_set_zone_name(stack_logging_lite_zone, MALLOC_STOCK_LOGGING_LITE_ZONE_NAME);
-	lite_zone = stack_logging_lite_zone;
-}
-
-boolean_t
-turn_on_stack_logging(stack_logging_mode_type mode)
-{
-	boolean_t ret = false;
+#if CONFIG_NANOZONE
+	// TODO: envp should be passed down from Libsystem
+	const char **envp = (const char **)*_NSGetEnviron();
 	
-	MALLOC_LOCK();
-	
-	if (!stack_logging_enable_logging) {
-		if (__uniquing_table_memory_was_deleted()) {
-			// It would great to be able re-enable even if the uniquing table has been deleted
-			// <rdar://problem/25014005> malloc stack logging should be able to recreate the uniquing table if needed
-		} else {
-			switch (mode) {
-				case stack_logging_mode_all:
-					__prepare_to_log_stacks(false);
-					malloc_logger = __disk_stack_logging_log_stack;
-					__syscall_logger = __disk_stack_logging_log_stack;
-					stack_logging_mode = mode;
-					stack_logging_enable_logging = 1;
-					ret = true;
-					
-					malloc_printf("recording malloc and VM allocation stacks to disk using standard recorder\n");
-					break;
-					
-				case stack_logging_mode_malloc:
-					__prepare_to_log_stacks(false);
-					malloc_logger = __disk_stack_logging_log_stack;
-					stack_logging_mode = mode;
-					stack_logging_enable_logging = 1;
-					ret = true;
-					
-					malloc_printf("recording malloc (but not VM allocation) stacks to disk using standard recorder\n");
-					break;
-					
-				case stack_logging_mode_vm:
-					__prepare_to_log_stacks(false);
-					__syscall_logger = __disk_stack_logging_log_stack;
-					stack_logging_mode = mode;
-					stack_logging_enable_logging = 1;
-					ret = true;
-					
-					malloc_printf("recording VM allocation (but not malloc) stacks to disk using standard recorder\n");
-					break;
-					
-				case stack_logging_mode_lite:
-					if (!has_default_zone0()) {
-						malloc_printf("zone[0] is not the normal default zone so can't turn on lite mode.\n", mode);
-						ret = false;
-					} else {
-						malloc_printf("recording malloc (and VM allocation) stacks using lite mode\n");
-						
-						if (lite_zone) {
-							enable_stack_logging_lite();
-						} else {
-							if (__prepare_to_log_stacks(true)) {
-								__syscall_logger = __disk_stack_logging_log_stack;
-								stack_logging_mode = stack_logging_mode_lite;
-								stack_logging_enable_logging = 1;
-								__prepare_to_log_stacks_stage2();
-								create_and_insert_lite_zone_while_locked();
-								enable_stack_logging_lite();
-							}
-						}
-						ret = true;
-					}
-					break;
-					
-				default:
-					malloc_printf("invalid mode %d passed to turn_on_stack_logging\n", mode);
-					break;
-			}
-		}
+	// Force magazine_malloc when:
+	// - quarantine 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
+	if (!malloc_quarantine_enabled &&
+			!(malloc_debug_flags & MALLOC_DO_SCRIBBLE) &&
+			!malloc_zero_on_free_sample_period) {
+		nano_common_init(envp, apple, bootargs);
+	}
+#endif // CONFIG_NANOZONE
+
+	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);
+
+#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);
+	}
+#endif
+
+#if CONFIG_QUARANTINE
+	if (malloc_quarantine_enabled) {
+		malloc_zone_t *wrapped_zone = malloc_zones[0];
+		malloc_zone_t *quarantine_zone = quarantine_create_zone(wrapped_zone);
+		malloc_zone_register_while_locked(quarantine_zone, /*make_default=*/true);
+	}
+#endif
+
+	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) {
+			MALLOC_REPORT_FATAL_ERROR(kr, "Unable to set up reclaim buffer.\n");
+		}
+	}
+#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 {
-		malloc_printf("malloc stack logging already enabled.\n");
-	}
-	
-	MALLOC_UNLOCK();
-	
-	return ret;
-}
-
-void
-turn_off_stack_logging()
-{
-	MALLOC_LOCK();
-	
-	if (stack_logging_enable_logging) {
-		switch (stack_logging_mode) {
-			case stack_logging_mode_all:
-				malloc_logger = NULL;
-				__syscall_logger = NULL;
-				stack_logging_enable_logging = 0;
-				malloc_printf("turning off recording malloc and VM allocation stacks to disk using standard recorder\n");
-				break;
-				
-			case stack_logging_mode_malloc:
-				malloc_logger = NULL;
-				stack_logging_enable_logging = 0;
-				malloc_printf("turnning off recording malloc (but not VM allocation) stacks to disk using standard recorder\n");
-				break;
-				
-			case stack_logging_mode_vm:
-				__syscall_logger = NULL;
-				stack_logging_enable_logging = 0;
-				malloc_printf("turning off recording VM allocation (but not malloc) stacks to disk using standard recorder\n");
-				break;
-				
-			case stack_logging_mode_lite:
-				malloc_printf("turning off recording malloc (but not VM allocation) stacks using lite mode\n");
-				
-				disable_stack_logging_lite();
-				stack_logging_enable_logging = 0;
-				break;
-				
-			default:
-				malloc_printf("invalid stack_logging_mode %d in turn_off_stack_logging\n", stack_logging_mode);
-				break;
-		}
-	} else {
-		malloc_printf("malloc stack logging not enabled.\n");
-	}
-	
-	MALLOC_UNLOCK();
-}
-
-// To be used in _malloc_initialize_once() only, call that function instead.
+		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 internal_build;
+static bool
+enable_pgm(void)
+{
+	bool other_debug_tool = has_injected_zone0 || malloc_quarantine_enabled;
+	return !other_debug_tool && pgm_should_enable(internal_build);
+}
+
 static void
-_malloc_initialize(void *context __unused)
-{
-	MALLOC_LOCK();
-	unsigned n;
-	malloc_zone_t *zone;
-
-	if (!_malloc_entropy_initialized) {
-		// Lazy initialization may occur before __malloc_init (rdar://27075409)
-		// TODO: make this a fatal error
-		malloc_printf("*** malloc was initialized without entropy\n");
-	}
-
-	set_flags_from_environment(); // will only set flags up to two times
-	n = malloc_num_zones;
-
-#if CONFIG_NANOZONE
-	malloc_zone_t *helper_zone = create_scalable_zone(0, malloc_debug_flags);
-	zone = create_nano_zone(0, helper_zone, malloc_debug_flags);
-
-	if (zone) {
-		malloc_zone_register_while_locked(zone);
-		malloc_zone_register_while_locked(helper_zone);
-
-		// Must call malloc_set_zone_name() *after* helper and nano are hooked together.
-		malloc_set_zone_name(zone, DEFAULT_MALLOC_ZONE_STRING);
-		malloc_set_zone_name(helper_zone, MALLOC_HELPER_ZONE_STRING);
-	} else {
-		zone = helper_zone;
-		malloc_zone_register_while_locked(zone);
-		malloc_set_zone_name(zone, DEFAULT_MALLOC_ZONE_STRING);
-	}
-#else
-	zone = create_scalable_zone(0, malloc_debug_flags);
-	malloc_zone_register_while_locked(zone);
-	malloc_set_zone_name(zone, DEFAULT_MALLOC_ZONE_STRING);
-#endif
-
-	initial_default_zone = zone;
-
-	if (n != 0) { // make the default first, for efficiency
-		unsigned protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
-		malloc_zone_t *hold = malloc_zones[0];
-
-		if (hold->zone_name && strcmp(hold->zone_name, DEFAULT_MALLOC_ZONE_STRING) == 0) {
-			malloc_set_zone_name(hold, NULL);
-		}
-
-		mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);
-		malloc_zones[0] = malloc_zones[n];
-		malloc_zones[n] = hold;
-		mprotect(malloc_zones, protect_size, PROT_READ);
-	}
-
-	// Only setup stack logging hooks once lazy initialization is complete, the
-	// malloc_zone calls above would otherwise initialize malloc stack logging,
-	// which calls into malloc re-entrantly from Libc upcalls and so deadlocks
-	// in the lazy initialization os_once(). rdar://13046853
-	if (stack_logging_enable_logging) {
-		switch (stack_logging_mode) {
-		case stack_logging_mode_malloc:
-			malloc_logger = __disk_stack_logging_log_stack;
-			break;
-		case stack_logging_mode_vm:
-			__syscall_logger = __disk_stack_logging_log_stack;
-			break;
-		case stack_logging_mode_all:
-			malloc_logger = __disk_stack_logging_log_stack;
-			__syscall_logger = __disk_stack_logging_log_stack;
-			break;
-		case stack_logging_mode_lite:
-			__syscall_logger = __disk_stack_logging_log_stack;
-			create_and_insert_lite_zone_while_locked();
-			enable_stack_logging_lite();
-			break;
-		}
-	}
-
-	// _malloc_printf(ASL_LEVEL_INFO, "%d registered zones\n", malloc_num_zones);
-	// _malloc_printf(ASL_LEVEL_INFO, "malloc_zones is at %p; malloc_num_zones is at %p\n", (unsigned)&malloc_zones,
-	// (unsigned)&malloc_num_zones);
-	MALLOC_UNLOCK();
-}
-
-MALLOC_ALWAYS_INLINE
-static inline void
-_malloc_initialize_once(void)
-{
-	os_once(&_malloc_initialize_pred, NULL, _malloc_initialize);
+register_pgm_zone(bool internal_diagnostics)
+{
+	if (internal_diagnostics) {
+		internal_build = true;
+	}
+	if (enable_pgm()) {
+		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);
+	}
 }
 
 static inline malloc_zone_t *
 inline_malloc_default_zone(void)
 {
-	_malloc_initialize_once();
-	// _malloc_printf(ASL_LEVEL_INFO, "In inline_malloc_default_zone with %d %d\n", malloc_num_zones, malloc_has_debug_zone);
+	// malloc_report(ASL_LEVEL_INFO, "In inline_malloc_default_zone with %d %d\n", malloc_num_zones, malloc_has_debug_zone);
 	return malloc_zones[0];
 }
 
@@ -880,46 +1117,13 @@
 	return default_zone;
 }
 
-static inline malloc_zone_t *inline_malloc_default_scalable_zone(void) __attribute__((always_inline));
-static inline malloc_zone_t *
-inline_malloc_default_scalable_zone(void)
-{
-	unsigned index;
-
-	_malloc_initialize_once();
-	// _malloc_printf(ASL_LEVEL_INFO, "In inline_malloc_default_scalable_zone with %d %d\n", malloc_num_zones,
-	// malloc_has_debug_zone);
-
-	MALLOC_LOCK();
-#if CONFIG_NANOZONE
-	for (index = 0; index < malloc_num_zones; ++index) {
-		malloc_zone_t *z = malloc_zones[index];
-
-		if (z->zone_name && strcmp(z->zone_name, MALLOC_HELPER_ZONE_STRING) == 0) {
-			MALLOC_UNLOCK();
-			return z;
-		}
-	}
-#endif
-	for (index = 0; index < malloc_num_zones; ++index) {
-		malloc_zone_t *z = malloc_zones[index];
-
-		if (z->zone_name && strcmp(z->zone_name, DEFAULT_MALLOC_ZONE_STRING) == 0) {
-			MALLOC_UNLOCK();
-			return z;
-		}
-	}
-	MALLOC_UNLOCK();
-
-	malloc_printf("*** malloc_default_scalable_zone() failed to find 'DefaultMallocZone'\n");
-	return NULL; // FIXME: abort() instead?
-}
-
 static void *
 legacy_zeroing_large_malloc(malloc_zone_t *zone, size_t size)
 {
-	if (size > LARGE_THRESHOLD) {			 // Leopard and earlier returned a ZFOD range, so ...
-		return default_zone_calloc(zone, 1, size); // Clear to zero always, ham-handedly touching in each page
+	if (size > LEGACY_ZEROING_THRESHOLD) {
+		// Leopard and earlier returned a ZFOD range, so clear to zero always,
+		// ham-handedly touching in each page
+		return default_zone_calloc(zone, 1, size);
 	} else {
 		return default_zone_malloc(zone, size);
 	}
@@ -951,9 +1155,9 @@
 }
 
 /*
- * malloc_engaged_nano() is for the benefit of libdispatch, which calls here just once.
+ * Returns the version of the Nano allocator that's in use, or 0 if not.
  */
-boolean_t
+int
 malloc_engaged_nano(void)
 {
 #if CONFIG_NANOZONE
@@ -973,7 +1177,7 @@
 		// 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, inline_malloc_default_scalable_zone(), malloc_debug_flags);
+		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)) {
@@ -987,16 +1191,10 @@
 set_flags_from_environment(void)
 {
 	const char *flag;
-	int fd;
-	char **env = *_NSGetEnviron();
-	char **p;
-	char *c;
-	bool restricted = 0;
-
-	if (malloc_debug_file != STDERR_FILENO) {
-		close(malloc_debug_file);
-		malloc_debug_file = STDERR_FILENO;
-	}
+	const char **env = (const char **)*_NSGetEnviron();
+	const char **p;
+	const char *c;
+
 #if __LP64__
 	malloc_debug_flags = MALLOC_ABORT_ON_CORRUPTION; // Set always on 64-bit processes
 #else
@@ -1007,13 +1205,17 @@
 		malloc_debug_flags = MALLOC_ABORT_ON_CORRUPTION;
 	}
 #endif
-	stack_logging_enable_logging = 0;
-	stack_logging_dontcompact = 0;
-	malloc_logger = NULL;
-	malloc_check_start = 0;
-	malloc_check_each = 1000;
-	malloc_check_abort = 0;
-	malloc_check_sleep = 100;
+
+#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
 	 * first the environment, therefore avoiding repeated calls to getenv().
@@ -1021,7 +1223,11 @@
 	 * our behaviour.
 	 */
 	for (p = env; (c = *p) != NULL; ++p) {
+#if RDAR_48993662
+		if (!strncmp(c, "Malloc", 6) || !strncmp(c, "_Malloc", 6)) {
+#else // RDAR_48993662
 		if (!strncmp(c, "Malloc", 6)) {
+#endif // RDAR_48993662
 			if (issetugid()) {
 				return;
 			}
@@ -1034,82 +1240,52 @@
 	 * MallocLogFile & MallocCorruptionAbort
 	 * as these provide the ability to turn *off* aborting in error cases.
 	 */
-	restricted = dyld_process_is_restricted();
+	bool restricted = dyld_process_is_restricted();
+	malloc_print_configure(restricted);
 
 	if (c == NULL) {
 		return;
 	}
-	if (!restricted) {
-		flag = getenv("MallocLogFile");
-		if (flag) {
-			fd = open(flag, O_WRONLY | O_APPEND | O_CREAT, 0644);
-			if (fd >= 0) {
-				malloc_debug_file = fd;
-				fcntl(fd, F_SETFD, 0); // clear close-on-exec flag  XXX why?
-			} else {
-				malloc_printf("Could not open %s, using stderr\n", flag);
+
+	flag = getenv("MallocGuardEdges");
+	if (flag) {
+		if (!strcmp(flag, "all")) {
+			// "MallocGuardEdges=all" adds guard page(s) for every region.
+			// Do not do this on 32-bit platforms because there is insufficient
+			// address space. These pages are always protected.
+#if MALLOC_TARGET_64BIT
+			malloc_debug_flags |= MALLOC_GUARD_ALL | MALLOC_ADD_GUARD_PAGE_FLAGS;
+			malloc_debug_flags &= ~(MALLOC_DONT_PROTECT_PRELUDE|MALLOC_DONT_PROTECT_POSTLUDE);
+			malloc_report(ASL_LEVEL_INFO, "adding guard pages to all regions\n");
+#endif // MALLOC_TARGET_64BIT
+		} else {
+			malloc_debug_flags |= MALLOC_ADD_GUARD_PAGE_FLAGS;
+			malloc_debug_flags &= ~MALLOC_GUARD_ALL;
+			malloc_report(ASL_LEVEL_INFO, "adding guard pages for large allocator blocks\n");
+			if (getenv("MallocDoNotProtectPrelude")) {
+				malloc_debug_flags |= MALLOC_DONT_PROTECT_PRELUDE;
+				malloc_report(ASL_LEVEL_INFO, "... but not protecting prelude guard page\n");
 			}
-		}
-	}
-	if (getenv("MallocGuardEdges")) {
-		malloc_debug_flags |= MALLOC_ADD_GUARD_PAGES;
-		_malloc_printf(ASL_LEVEL_INFO, "protecting edges\n");
-		if (getenv("MallocDoNotProtectPrelude")) {
-			malloc_debug_flags |= MALLOC_DONT_PROTECT_PRELUDE;
-			_malloc_printf(ASL_LEVEL_INFO, "... but not protecting prelude guard page\n");
-		}
-		if (getenv("MallocDoNotProtectPostlude")) {
-			malloc_debug_flags |= MALLOC_DONT_PROTECT_POSTLUDE;
-			_malloc_printf(ASL_LEVEL_INFO, "... but not protecting postlude guard page\n");
-		}
-	}
-	flag = getenv("MallocStackLogging");
-	if (!flag) {
-		flag = getenv("MallocStackLoggingNoCompact");
-		stack_logging_dontcompact = 1;
-	}
-	if (flag) {
-		// Set up stack logging as early as possible to catch all ensuing VM allocations,
-		// including those from _malloc_printf and malloc zone setup.  Make sure to set
-		// __syscall_logger after this, because prepare_to_log_stacks() itself makes VM
-		// allocations that we aren't prepared to log yet.
-		boolean_t lite_mode = strcmp(flag, "lite") == 0;
-		
-		__prepare_to_log_stacks(lite_mode);
-
-		if (strcmp(flag, "lite") == 0) {
-			stack_logging_mode = stack_logging_mode_lite;
-			_malloc_printf(ASL_LEVEL_INFO, "recording malloc and VM allocation stacks using lite mode\n");
-		} else if (strcmp(flag,"malloc") == 0) {
-			stack_logging_mode = stack_logging_mode_malloc;
-			_malloc_printf(ASL_LEVEL_INFO, "recording malloc (but not VM allocation) stacks to disk using standard recorder\n");
-		} else if (strcmp(flag, "vm") == 0) {
-			stack_logging_mode = stack_logging_mode_vm;
-			_malloc_printf(ASL_LEVEL_INFO, "recording VM allocation (but not malloc) stacks to disk using standard recorder\n");
-		} else {
-			stack_logging_mode = stack_logging_mode_all;
-			_malloc_printf(ASL_LEVEL_INFO, "recording malloc and VM allocation stacks to disk using standard recorder\n");
-		}
-		stack_logging_enable_logging = 1;
-		if (stack_logging_dontcompact) {
-			if (stack_logging_mode == stack_logging_mode_all || stack_logging_mode == stack_logging_mode_malloc) {
-				_malloc_printf(
-						ASL_LEVEL_INFO, "stack logging compaction turned off; size of log files on disk can increase rapidly\n");
-			} else {
-				_malloc_printf(ASL_LEVEL_INFO, "stack logging compaction turned off; VM can increase rapidly\n");
+			if (getenv("MallocDoNotProtectPostlude")) {
+				malloc_debug_flags |= MALLOC_DONT_PROTECT_POSTLUDE;
+				malloc_report(ASL_LEVEL_INFO, "... but not protecting postlude guard page\n");
 			}
 		}
 	}
+
 	if (getenv("MallocScribble")) {
 		malloc_debug_flags |= MALLOC_DO_SCRIBBLE;
-		_malloc_printf(ASL_LEVEL_INFO, "enabling scribbling to detect mods to free blocks\n");
+		malloc_report(ASL_LEVEL_INFO, "enabling scribbling to detect mods to free blocks\n");
 	}
 	if (getenv("MallocErrorAbort")) {
 		malloc_debug_flags |= MALLOC_ABORT_ON_ERROR;
-		_malloc_printf(ASL_LEVEL_INFO, "enabling abort() on bad malloc or free\n");
+		malloc_report(ASL_LEVEL_INFO, "enabling abort() on bad malloc or free\n");
 	}
 	if (getenv("MallocTracing")) {
 		malloc_tracing_enabled = true;
+	}
+	if (getenv("MallocSimpleStackLogging")) {
+		malloc_simple_stack_logging = true;
 	}
 
 #if __LP64__
@@ -1141,30 +1317,235 @@
 				malloc_check_each = 1;
 			}
 		}
-		_malloc_printf(
-				ASL_LEVEL_INFO, "checks heap after %dth operation and each %d operations\n", malloc_check_start, malloc_check_each);
+		malloc_report(ASL_LEVEL_INFO, "checks heap after operation #%d and each %d operations\n", malloc_check_start, malloc_check_each);
 		flag = getenv("MallocCheckHeapAbort");
 		if (flag) {
 			malloc_check_abort = (unsigned)strtol(flag, NULL, 0);
 		}
 		if (malloc_check_abort) {
-			_malloc_printf(ASL_LEVEL_INFO, "will abort on heap corruption\n");
+			malloc_report(ASL_LEVEL_INFO, "will abort on heap corruption\n");
 		} else {
 			flag = getenv("MallocCheckHeapSleep");
 			if (flag) {
 				malloc_check_sleep = (unsigned)strtol(flag, NULL, 0);
 			}
 			if (malloc_check_sleep > 0) {
-				_malloc_printf(ASL_LEVEL_INFO, "will sleep for %d seconds on heap corruption\n", malloc_check_sleep);
+				malloc_report(ASL_LEVEL_INFO, "will sleep for %d seconds on heap corruption\n", malloc_check_sleep);
 			} else if (malloc_check_sleep < 0) {
-				_malloc_printf(ASL_LEVEL_INFO, "will sleep once for %d seconds on heap corruption\n", -malloc_check_sleep);
+				malloc_report(ASL_LEVEL_INFO, "will sleep once for %d seconds on heap corruption\n", -malloc_check_sleep);
 			} else {
-				_malloc_printf(ASL_LEVEL_INFO, "no sleep on heap corruption\n");
+				malloc_report(ASL_LEVEL_INFO, "no sleep on heap corruption\n");
 			}
 		}
 	}
+
+	flag = getenv("MallocMaxMagazines");
+#if RDAR_48993662
+	if (!flag) {
+		flag = getenv("_MallocMaxMagazines");
+	}
+#endif // RDAR_48993662
+	if (flag) {
+		int value = (unsigned)strtol(flag, NULL, 0);
+		if (value == 0) {
+			malloc_report(ASL_LEVEL_INFO, "Maximum magazines defaulted to %d\n", max_magazines);
+		} else if (value < 0) {
+			malloc_report(ASL_LEVEL_ERR, "Maximum magazines must be positive - ignored.\n");
+		} else if (value > logical_ncpus) {
+			max_magazines = logical_ncpus;
+			malloc_report(ASL_LEVEL_INFO, "Maximum magazines limited to number of logical CPUs (%d)\n", max_magazines);
+		} else {
+			max_magazines = value;
+			malloc_report(ASL_LEVEL_INFO, "Maximum magazines set to %d\n", max_magazines);
+		}
+	}
+
+	flag = getenv("MallocLargeExpandedCacheThreshold");
+	if (flag) {
+		uint64_t value = (uint64_t)strtoull(flag, NULL, 0);
+		if (value == 0) {
+			malloc_report(ASL_LEVEL_INFO, "Large expanded cache threshold defaulted to %lly\n", magazine_large_expanded_cache_threshold);
+		} else if (value < 0) {
+			malloc_report(ASL_LEVEL_ERR, "MallocLargeExpandedCacheThreshold must be positive - ignored.\n");
+		} else {
+			magazine_large_expanded_cache_threshold = value;
+			malloc_report(ASL_LEVEL_INFO, "Large expanded cache threshold set to %lly\n", magazine_large_expanded_cache_threshold);
+		}
+	}
+
+	flag = getenv("MallocLargeDisableASLR");
+	if (flag) {
+		uint64_t value = (uint64_t)strtoull(flag, NULL, 0);
+		if (value == 0) {
+			malloc_report(ASL_LEVEL_INFO, "Enabling ASLR slide on large allocations\n");
+			malloc_debug_flags &= ~DISABLE_LARGE_ASLR;
+		} else if (value != 0) {
+			malloc_report(ASL_LEVEL_INFO, "Disabling ASLR slide on large allocations\n");
+			malloc_debug_flags |= DISABLE_LARGE_ASLR;
+		}
+	}
+
+#if CONFIG_AGGRESSIVE_MADVISE || CONFIG_LARGE_CACHE
+	// convenience flag to configure policies usually associated with memory-constrained platforms (iOS)
+	// that trade some amount of time efficiency for space efficiency
+	flag = getenv("MallocSpaceEfficient");
+	if (flag) {
+		const char *endp;
+		long value = malloc_common_convert_to_long(flag, &endp);
+		if (!*endp && endp != flag && (value == 0 || value == 1)) {
+#if CONFIG_AGGRESSIVE_MADVISE
+			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;
+			}
+#endif // CONFIG_LARGE_CACHE
+			malloc_space_efficient_enabled = (value == 1);
+			// consider disabling medium magazine if aggressive madvise is not sufficient
+		} else {
+			malloc_report(ASL_LEVEL_ERR, "MallocSpaceEfficient must be 0 or 1.\n");
+		}
+	}
+#endif // CONFIG_AGGRESSIVE_MADVISE || CONFIG_LARGE_CACHE
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	flag = getenv("MallocMediumZone");
+	if (flag) {
+		int value = (unsigned)strtol(flag, NULL, 0);
+		if (value == 0) {
+			magazine_medium_enabled = false;
+		} else if (value == 1) {
+			magazine_medium_enabled = true;
+		}
+	}
+
+	flag = getenv("MallocMediumActivationThreshold");
+	if (flag) {
+		uint64_t value = (uint64_t)strtoull(flag, NULL, 0);
+		if (value == 0) {
+			malloc_report(ASL_LEVEL_INFO, "Medium activation threshold defaulted to %lly\n", magazine_medium_active_threshold);
+		} else if (value < 0) {
+			malloc_report(ASL_LEVEL_ERR, "MallocMediumActivationThreshold must be positive - ignored.\n");
+		} else {
+			magazine_medium_active_threshold = value;
+			malloc_report(ASL_LEVEL_INFO, "Medium activation threshold set to %lly\n", magazine_medium_active_threshold);
+		}
+	}
+
+	flag = getenv("MallocMediumSpaceEfficient");
+	if (flag) {
+		uint64_t value = (uint64_t)strtoull(flag, NULL, 0);
+		if (value == 0) {
+			malloc_medium_space_efficient_enabled = false;
+		} else if (value == 1) {
+			malloc_medium_space_efficient_enabled = true;
+		}
+	}
+
+	if (malloc_medium_space_efficient_enabled && malloc_space_efficient_enabled) {
+		// Bring down MallocMaxMediumMagazines to only a single magazine in
+		// space-efficent processes but do this before the envvar so that it
+		// can still be overridden at the command line.
+		max_medium_magazines = 1;
+	}
+
+	flag = getenv("MallocMaxMediumMagazines");
+#if RDAR_48993662
+	if (!flag) {
+		flag = getenv("_MallocMaxMediumMagazines");
+	}
+#endif // RDAR_48993662
+	if (flag) {
+		int value = (unsigned)strtol(flag, NULL, 0);
+		if (value == 0) {
+			malloc_report(ASL_LEVEL_INFO, "Maximum medium magazines defaulted to %d\n", max_magazines);
+		} else if (value < 0) {
+			malloc_report(ASL_LEVEL_ERR, "Maximum medium magazines must be positive - ignored.\n");
+		} else if (value > logical_ncpus) {
+			max_medium_magazines = logical_ncpus;
+			malloc_report(ASL_LEVEL_INFO, "Maximum medium magazines limited to number of logical CPUs (%d)\n", max_medium_magazines);
+		} else {
+			max_medium_magazines = value;
+			malloc_report(ASL_LEVEL_INFO, "Maximum medium magazines set to %d\n", max_medium_magazines);
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+#if CONFIG_AGGRESSIVE_MADVISE
+	flag = getenv("MallocAggressiveMadvise");
+	if (flag) {
+		const char *endp;
+		long value = malloc_common_convert_to_long(flag, &endp);
+		if (!*endp && endp != flag && (value == 0 || value == 1)) {
+			aggressive_madvise_enabled = (value == 1);
+		} else {
+			malloc_report(ASL_LEVEL_ERR, "MallocAggressiveMadvise must be 0 or 1.\n");
+		}
+	}
+#endif // CONFIG_AGGRESSIVE_MADVISE
+
+#if CONFIG_LARGE_CACHE
+	flag = getenv("MallocLargeCache");
+	if (flag) {
+		const char *endp;
+		long value = malloc_common_convert_to_long(flag, &endp);
+		if (!*endp && endp != flag && (value == 0 || value == 1)) {
+			large_cache_enabled = (value == 1);
+		} else {
+			malloc_report(ASL_LEVEL_ERR, "MallocLargeCache must be 0 or 1.\n");
+		}
+	}
+#endif // CONFIG_LARGE_CACHE
+
+#if CONFIG_RECIRC_DEPOT
+	flag = getenv("MallocRecircRetainedRegions");
+	if (flag) {
+		int value = (int)strtol(flag, NULL, 0);
+		if (value > 0) {
+			recirc_retained_regions = value;
+		} else {
+			malloc_report(ASL_LEVEL_ERR, "MallocRecircRetainedRegions must be positive - ignored.\n");
+		}
+	}
+#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");
+		}
+	}
+
 	if (getenv("MallocHelp")) {
-		_malloc_printf(ASL_LEVEL_INFO,
+		malloc_report(ASL_LEVEL_INFO,
 				"environment variables that can be set for debug:\n"
 				"- MallocLogFile <f> to create/append messages to file <f> instead of stderr\n"
 				"- MallocGuardEdges to add 2 guard pages for each large block\n"
@@ -1183,6 +1564,8 @@
 				"  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");
 	}
 }
@@ -1193,12 +1576,19 @@
 	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;
 	}
-	_malloc_initialize_once();
+
 	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;
 }
 
@@ -1210,13 +1600,10 @@
 malloc_create_legacy_default_zone(void)
 {
 	malloc_zone_t *zone;
-	int i;
-
-	_malloc_initialize_once();
+
 	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.
@@ -1227,16 +1614,7 @@
 	}
 	malloc_set_zone_name(zone, DEFAULT_MALLOC_ZONE_STRING);
 
-	unsigned protect_size = malloc_num_zones_allocated * sizeof(malloc_zone_t *);
-	mprotect(malloc_zones, protect_size, PROT_READ | PROT_WRITE);
-
-	// assert(zone == malloc_zones[malloc_num_zones - 1];
-	for (i = malloc_num_zones - 1; i > 0; --i) {
-		malloc_zones[i] = malloc_zones[i - 1];
-	}
-	malloc_zones[0] = zone;
-
-	mprotect(malloc_zones, protect_size, PROT_READ);
+	malloc_zone_register_while_locked(zone, /*make_default=*/true);
 	MALLOC_UNLOCK();
 }
 
@@ -1248,117 +1626,245 @@
 	zone->destroy(zone);
 }
 
+static vm_address_t *frames = NULL;
+static unsigned num_frames;
+
+MALLOC_NOINLINE
+void
+malloc_zone_check_fail(const char *msg, const char *fmt, ...)
+{
+	_SIMPLE_STRING b = _simple_salloc();
+	if (b) {
+		_simple_sprintf(b, "*** MallocCheckHeap: FAILED check at operation #%d\n", malloc_check_counter - 1);
+	} else {
+		malloc_report(MALLOC_REPORT_NOLOG, "*** MallocCheckHeap: FAILED check at operation #%d\n", malloc_check_counter - 1);
+	}
+	if (frames) {
+		unsigned index = 1;
+		if (b) {
+			_simple_sappend(b, "Stack for last operation where the malloc check succeeded: ");
+			while (index < num_frames)
+				_simple_sprintf(b, "%p ", (void*)frames[index++]);
+			malloc_report(MALLOC_REPORT_NOLOG, "%s\n(Use 'atos' for a symbolic stack)\n", _simple_string(b));
+		} else {
+			/*
+			 * Should only get here if vm_allocate() can't get a single page of
+			 * memory, implying _simple_asl_log() would also fail.  So we just
+			 * print to the file descriptor.
+			 */
+			malloc_report(MALLOC_REPORT_NOLOG, "Stack for last operation where the malloc check succeeded: ");
+			while (index < num_frames) {
+				malloc_report(MALLOC_REPORT_NOLOG, "%p ", (void *)frames[index++]);
+			}
+			malloc_report(MALLOC_REPORT_NOLOG, "\n(Use 'atos' for a symbolic stack)\n");
+		}
+	}
+	if (malloc_check_each > 1) {
+		unsigned recomm_each = (malloc_check_each > 10) ? malloc_check_each / 10 : 1;
+		unsigned recomm_start =
+				(malloc_check_counter > malloc_check_each + 1) ? malloc_check_counter - 1 - malloc_check_each : 1;
+		malloc_report(MALLOC_REPORT_NOLOG,
+				"*** Recommend using 'setenv MallocCheckHeapStart %d; setenv MallocCheckHeapEach %d' to narrow down failure\n",
+				recomm_start, recomm_each);
+	}
+
+	if (b) {
+		_simple_sfree(b);
+	}
+
+	// Use malloc_vreport() to:
+	// 	* report the error
+	// 	* call malloc_error_break() for a breakpoint
+	// 	* sleep or stop for debug
+	// 	* set the crash message and crash if malloc_check_abort is set.
+	unsigned sleep_time = 0;
+	uint32_t report_flags = ASL_LEVEL_ERR | MALLOC_REPORT_DEBUG | MALLOC_REPORT_NOLOG;
+	if (malloc_check_abort) {
+		report_flags |= MALLOC_REPORT_CRASH;
+	} else {
+		if (malloc_check_sleep > 0) {
+			malloc_report(ASL_LEVEL_NOTICE, "*** Will sleep for %d seconds to leave time to attach\n", malloc_check_sleep);
+			sleep_time = malloc_check_sleep;
+		} else if (malloc_check_sleep < 0) {
+			malloc_report(ASL_LEVEL_NOTICE, "*** Will sleep once for %d seconds to leave time to attach\n", -malloc_check_sleep);
+			sleep_time = -malloc_check_sleep;
+			malloc_check_sleep = 0;
+		}
+	}
+	va_list ap;
+	va_start(ap, fmt);
+	malloc_vreport(report_flags, sleep_time, msg, NULL, fmt, ap);
+	va_end(ap);
+}
+
 /*********	Block creation and manipulation	************/
 
+__attribute__((cold, noinline))
 static void
 internal_check(void)
 {
-	static vm_address_t *frames = NULL;
-	static unsigned num_frames;
+	if (malloc_check_counter++ < malloc_check_start) {
+		return;
+	}
 	if (malloc_zone_check(NULL)) {
 		if (!frames) {
 			vm_allocate(mach_task_self(), (void *)&frames, vm_page_size, 1);
 		}
 		thread_stack_pcs(frames, (unsigned)(vm_page_size / sizeof(vm_address_t) - 1), &num_frames);
-	} else {
-		_SIMPLE_STRING b = _simple_salloc();
-		if (b) {
-			_simple_sprintf(b, "*** MallocCheckHeap: FAILED check at %dth operation\n", malloc_check_counter - 1);
-		} else {
-			_malloc_printf(MALLOC_PRINTF_NOLOG, "*** MallocCheckHeap: FAILED check at %dth operation\n", malloc_check_counter - 1);
-		}
-		malloc_printf("*** MallocCheckHeap: FAILED check at %dth operation\n", malloc_check_counter - 1);
-		if (frames) {
-			unsigned index = 1;
-			if (b) {
-				_simple_sappend(b, "Stack for last operation where the malloc check succeeded: ");
-				while (index < num_frames)
-					_simple_sprintf(b, "%p ", (void*)frames[index++]);
-				malloc_printf("%s\n(Use 'atos' for a symbolic stack)\n", _simple_string(b));
-			} else {
-				/*
-				 * Should only get here if vm_allocate() can't get a single page of
-				 * memory, implying _simple_asl_log() would also fail.  So we just
-				 * print to the file descriptor.
-				 */
-				_malloc_printf(MALLOC_PRINTF_NOLOG, "Stack for last operation where the malloc check succeeded: ");
-				while (index < num_frames)
-					_malloc_printf(MALLOC_PRINTF_NOLOG, "%p ", frames[index++]);
-				_malloc_printf(MALLOC_PRINTF_NOLOG, "\n(Use 'atos' for a symbolic stack)\n");
-			}
-		}
-		if (malloc_check_each > 1) {
-			unsigned recomm_each = (malloc_check_each > 10) ? malloc_check_each / 10 : 1;
-			unsigned recomm_start =
-					(malloc_check_counter > malloc_check_each + 1) ? malloc_check_counter - 1 - malloc_check_each : 1;
-			malloc_printf(
-					"*** Recommend using 'setenv MallocCheckHeapStart %d; setenv MallocCheckHeapEach %d' to narrow down failure\n",
-					recomm_start, recomm_each);
-		}
-		if (malloc_check_abort) {
-			if (b) {
-				_os_set_crash_log_message_dynamic(_simple_string(b));
-			} else {
-				_os_set_crash_log_message("*** MallocCheckHeap: FAILED check");
-			}
-			abort();
-		} else if (b) {
-			_simple_sfree(b);
-		}
-		if (malloc_check_sleep > 0) {
-			_malloc_printf(ASL_LEVEL_NOTICE, "*** Sleeping for %d seconds to leave time to attach\n", malloc_check_sleep);
-			sleep(malloc_check_sleep);
-		} else if (malloc_check_sleep < 0) {
-			_malloc_printf(ASL_LEVEL_NOTICE, "*** Sleeping once for %d seconds to leave time to attach\n", -malloc_check_sleep);
-			sleep(-malloc_check_sleep);
-			malloc_check_sleep = 0;
-		}
 	}
 	malloc_check_start += malloc_check_each;
+}
+
+MALLOC_NOINLINE
+static void *
+_malloc_zone_malloc_instrumented_or_legacy(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) {
+		goto out;
+	}
+
+	ptr = zone->malloc(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, "malloc (%p/%llu): ",
+				ptr, (unsigned long long)size);
+	}
+
+	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);
+	}
+	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_instrumented || malloc_check_start ||
+				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);
 }
 
 void *
 malloc_zone_malloc(malloc_zone_t *zone, size_t size)
 {
-	MALLOC_TRACE(TRACE_malloc | DBG_FUNC_START, (uintptr_t)zone, size, 0, 0);
+	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)
+{
+	MALLOC_TRACE(TRACE_calloc | DBG_FUNC_START, (uintptr_t)zone, num_items, size, 0);
 
 	void *ptr;
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	if (malloc_check_start) {
 		internal_check();
 	}
-	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
-		return NULL;
-	}
-
-	ptr = zone->malloc(zone, size);		// if lite zone is passed in then we still call the lite methods
-
-	
-	if (malloc_logger) {
-		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);
+
+	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);
+	}
+
+	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
+static void *
+_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_instrumented || malloc_check_start ||
+				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);
 }
 
 void *
 malloc_zone_calloc(malloc_zone_t *zone, size_t num_items, size_t size)
 {
-	void *ptr;
-	size_t alloc_size;
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	return _malloc_zone_calloc(zone, num_items, size, MZ_NONE);
+}
+
+MALLOC_NOINLINE
+static void *
+_malloc_zone_valloc(malloc_zone_t *zone, size_t size, malloc_zone_options_t mzo)
+{
+	MALLOC_TRACE(TRACE_valloc | DBG_FUNC_START, (uintptr_t)zone, size, 0, 0);
+
+	void *ptr = NULL;
+	if (malloc_check_start) {
 		internal_check();
 	}
-	if (os_mul_overflow(num_items, size, &alloc_size) || alloc_size > MALLOC_ABSOLUTE_MAX_SIZE){
-		errno = ENOMEM;
-		return NULL;
-	}
-
-	ptr = zone->calloc(zone, num_items, size);
-	
-	if (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);
+	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, 0);
+out:
+	if (os_unlikely(ptr == NULL)) {
+		malloc_set_errno_fast(mzo, ENOMEM);
 	}
 	return ptr;
 }
@@ -1366,20 +1872,7 @@
 void *
 malloc_zone_valloc(malloc_zone_t *zone, size_t size)
 {
-	void *ptr;
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
-		internal_check();
-	}
-	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
-		return NULL;
-	}
-
-	ptr = zone->valloc(zone, size);
-	
-	if (malloc_logger) {
-		malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0, (uintptr_t)ptr, 0);
-	}
-	return ptr;
+	return _malloc_zone_valloc(zone, size, MZ_NONE);
 }
 
 void *
@@ -1388,19 +1881,25 @@
 	MALLOC_TRACE(TRACE_realloc | DBG_FUNC_START, (uintptr_t)zone, (uintptr_t)ptr, size, 0);
 
 	void *new_ptr;
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	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 (malloc_logger) {
+	if (os_unlikely(malloc_logger)) {
 		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);
 	}
+
+	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);
 	return new_ptr;
 }
@@ -1408,12 +1907,15 @@
 void
 malloc_zone_free(malloc_zone_t *zone, void *ptr)
 {
-	MALLOC_TRACE(TRACE_free, (uintptr_t)zone, (uintptr_t)ptr, 0, 0);
-
-	if (malloc_logger) {
+	MALLOC_TRACE(TRACE_free, (uintptr_t)zone, (uintptr_t)ptr, (ptr) ? *(uintptr_t*)ptr : 0, 0);
+
+	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 (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	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();
 	}
 
@@ -1423,12 +1925,16 @@
 static void
 malloc_zone_free_definite_size(malloc_zone_t *zone, void *ptr, size_t size)
 {
-	MALLOC_TRACE(TRACE_free, (uintptr_t)zone, (uintptr_t)ptr, size, 0);
-
-	if (malloc_logger) {
+	MALLOC_TRACE(TRACE_free, (uintptr_t)zone, (uintptr_t)ptr, size, (ptr && size) ? *(uintptr_t*)ptr : 0);
+
+	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 (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	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();
 	}
 
@@ -1441,41 +1947,87 @@
 	if (!ptr) {
 		return NULL;
 	} else {
-		return find_registered_zone(ptr, NULL);
-	}
+		return find_registered_zone(ptr, NULL, false);
+	}
+}
+
+MALLOC_NOINLINE
+static void *
+_malloc_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size,
+		malloc_zone_options_t mzo)
+{
+	MALLOC_TRACE(TRACE_memalign | DBG_FUNC_START, (uintptr_t)zone, alignment, size, 0);
+
+	void *ptr = NULL;
+	int err = ENOMEM;
+	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) {
+		goto out;
+	}
+	if (alignment < sizeof(void *) ||			  // excludes 0 == alignment
+			0 != (alignment & (alignment - 1))) { // relies on sizeof(void *) being a power of two.
+		err = EINVAL;
+		goto out;
+	}
+	if ((mzo & MZ_C11) && (size & (alignment - 1)) != 0) { /* C11 requires size to be a multiple of alignment */
+		err = EINVAL;
+		goto out;
+	}
+
+	if (!(zone->memalign)) {
+		goto out;
+	}
+	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);
+
+out:
+	if (os_unlikely(ptr == NULL)) {
+		if (mzo & MZ_POSIX) {
+			malloc_set_errno_fast(mzo, err);
+		}
+	}
+	return ptr;
 }
 
 void *
 malloc_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size)
 {
-	MALLOC_TRACE(TRACE_memalign | DBG_FUNC_START, (uintptr_t)zone, alignment, size, 0);
-
-	void *ptr;
-	if (zone->version < 5) { // Version must be >= 5 to look at the new memalign field.
-		return NULL;
-	}
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	return _malloc_zone_memalign(zone, alignment, size, MZ_NONE);
+}
+
+boolean_t
+malloc_zone_claimed_address(malloc_zone_t *zone, void *ptr)
+{
+	if (!ptr) {
+		// NULL is not a member of any zone.
+		return false;
+	}
+
+	if (malloc_check_start) {
 		internal_check();
 	}
-	if (size > MALLOC_ABSOLUTE_MAX_SIZE) {
-		return NULL;
-	}
-	if (alignment < sizeof(void *) ||			  // excludes 0 == alignment
-			0 != (alignment & (alignment - 1))) { // relies on sizeof(void *) being a power of two.
-		return NULL;
-	}
-
-	if (!(zone->memalign)) {
-		return NULL;
-	}
-	ptr = zone->memalign(zone, alignment, size);
-
-	if (malloc_logger) {
-		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);
-	return ptr;
+
+	if (zone->version < 10 || !zone->claimed_address) {
+		// For zones that have not implemented claimed_address, we always have
+		// to return true to avoid a false negative.
+		return true;
+	}
+
+	return zone->claimed_address(zone, ptr);
 }
 
 /*********	Functions for zone implementors	************/
@@ -1484,7 +2036,7 @@
 malloc_zone_register(malloc_zone_t *zone)
 {
 	MALLOC_LOCK();
-	malloc_zone_register_while_locked(zone);
+	malloc_zone_register_while_locked(zone, false);
 	MALLOC_UNLOCK();
 }
 
@@ -1516,8 +2068,12 @@
 
 		mprotect(malloc_zones, protect_size, PROT_READ);
 
+		// MAX(num_zones, 1) retains 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);
+
 		// Exchange the roles of the FRZ counters. The counter that has captured the number of threads presently
-		// executing *inside* find_regiatered_zone is swapped with the counter drained to zero last time through.
+		// executing *inside* find_registered_zone is swapped with the counter drained to zero last time through.
 		// The former is then allowed to drain to zero while this thread yields.
 		int32_t volatile *p = pFRZCounterLive;
 		pFRZCounterLive = pFRZCounterDrain;
@@ -1533,27 +2089,30 @@
 		return;
 	}
 	MALLOC_UNLOCK();
-	malloc_printf("*** malloc_zone_unregister() failed for %p\n", z);
+	malloc_report(ASL_LEVEL_ERR, "*** malloc_zone_unregister() failed for %p\n", z);
 }
 
 void
 malloc_set_zone_name(malloc_zone_t *z, const char *name)
 {
-	char *newName;
-
 	mprotect(z, sizeof(malloc_zone_t), PROT_READ | PROT_WRITE);
 	if (z->zone_name) {
-		free((char *)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);
+		}
 		z->zone_name = NULL;
 	}
 	if (name) {
 		size_t buflen = strlen(name) + 1;
-		newName = malloc_zone_malloc(z, buflen);
-		if (newName) {
-			strlcpy(newName, name, buflen);
-			z->zone_name = (const char *)newName;
+		if (_dyld_is_memory_immutable(name, buflen)) {
+			z->zone_name = name;
 		} else {
-			z->zone_name = NULL;
+			char *name_copy = _malloc_zone_malloc(z, buflen, MZ_NONE);
+			if (name_copy) {
+				strlcpy(name_copy, name, buflen);
+				z->zone_name = name_copy;
+			}
 		}
 	}
 	mprotect(z, sizeof(malloc_zone_t), PROT_READ);
@@ -1565,108 +2124,72 @@
 	return zone->zone_name;
 }
 
-/*
- * XXX malloc_printf now uses _simple_*printf.  It only deals with a
- * subset of printf format specifiers, but it doesn't call malloc.
- */
-
-__attribute__((visibility("hidden"))) void
-_malloc_vprintf(int flags, const char *format, va_list ap)
-{
-	_SIMPLE_STRING b;
-
-	if (_malloc_no_asl_log || (flags & MALLOC_PRINTF_NOLOG) || (b = _simple_salloc()) == NULL) {
-		if (!(flags & MALLOC_PRINTF_NOPREFIX)) {
-			void *self = _os_tsd_get_direct(__TSD_THREAD_SELF);
-			_simple_dprintf(malloc_debug_file, "%s(%d,%p) malloc: ", getprogname(), getpid(), self);
-		}
-		_simple_vdprintf(malloc_debug_file, format, ap);
-		return;
-	}
-	if (!(flags & MALLOC_PRINTF_NOPREFIX)) {
-		void *self = _os_tsd_get_direct(__TSD_THREAD_SELF);
-		_simple_sprintf(b, "%s(%d,%p) malloc: ", getprogname(), getpid(), self);
-	}
-	_simple_vsprintf(b, format, ap);
-	_simple_put(b, malloc_debug_file);
-	_simple_asl_log(flags & MALLOC_PRINTF_LEVEL_MASK, Malloc_Facility, _simple_string(b));
-	_simple_sfree(b);
-}
-
-__attribute__((visibility("hidden"))) void
-_malloc_printf(int flags, const char *format, ...)
-{
-	va_list ap;
-
-	va_start(ap, format);
-	_malloc_vprintf(flags, format, ap);
-	va_end(ap);
-}
-
 void
-malloc_printf(const char *format, ...)
-{
-	va_list ap;
-
-	va_start(ap, format);
-	_malloc_vprintf(ASL_LEVEL_ERR, format, ap);
-	va_end(ap);
-}
-
-/*********	Generic ANSI callouts	************/
-
-void *
-malloc(size_t size)
-{
-	void *retval;
-	retval = malloc_zone_malloc(default_zone, size);
-	if (retval == NULL) {
-		errno = ENOMEM;
-	}
-	return retval;
-}
-
-void *
-calloc(size_t num_items, size_t size)
-{
-	void *retval;
-	retval = malloc_zone_calloc(default_zone, num_items, size);
-	if (retval == NULL) {
-		errno = ENOMEM;
-	}
-	return retval;
-}
-
-void
-free(void *ptr)
+find_zone_and_free(void *ptr, bool known_non_default)
 {
 	malloc_zone_t *zone;
 	size_t size;
 	if (!ptr) {
 		return;
 	}
-	zone = find_registered_zone(ptr, &size);
+
+	zone = find_registered_zone(ptr, &size, known_non_default);
 	if (!zone) {
-		malloc_printf(
-				"*** error for object %p: pointer being freed was not allocated\n"
-				"*** set a breakpoint in malloc_error_break to debug\n",
-				ptr);
-		malloc_error_break();
+		int flags = MALLOC_REPORT_DEBUG | MALLOC_REPORT_NOLOG;
 		if ((malloc_debug_flags & (MALLOC_ABORT_ON_CORRUPTION | MALLOC_ABORT_ON_ERROR))) {
-			_SIMPLE_STRING b = _simple_salloc();
-			if (b) {
-				_simple_sprintf(b, "*** error for object %p: pointer being freed was not allocated\n", ptr);
-				_os_set_crash_log_message_dynamic(_simple_string(b));
-			} else {
-				_os_set_crash_log_message("*** error: pointer being freed was not allocated\n");
-			}
-			abort();
-		}
+			flags = MALLOC_REPORT_CRASH | MALLOC_REPORT_NOLOG;
+		}
+		malloc_report(flags,
+				"*** error for object %p: pointer being freed was not allocated\n", ptr);
 	} else if (zone->version >= 6 && zone->free_definite_size) {
 		malloc_zone_free_definite_size(zone, ptr, size);
 	} else {
 		malloc_zone_free(zone, ptr);
 	}
+}
+
+
+/*********	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)
+{
+	if (!ptr) {
+		return;
+	}
+
+	if (os_unlikely(malloc_instrumented ||
+				malloc_check_start ||
+				malloc_logger ||
+				lite_zone ||
+				malloc_num_zones == 0 ||
+				malloc_zones[0]->version < 13 ||
+				!malloc_zones[0]->try_free_default)) {
+		find_zone_and_free(ptr, false);
+		return;
+	}
+
+	malloc_zone_t *zone0 = malloc_zones[0];
+	zone0->try_free_default(zone0, ptr);
 }
 
 void *
@@ -1688,29 +2211,20 @@
 	if (!old_ptr) {
 		retval = malloc_zone_malloc(default_zone, new_size);
 	} else {
-		zone = find_registered_zone(old_ptr, NULL);
+		zone = find_registered_zone(old_ptr, NULL, false);
 		if (!zone) {
-			malloc_printf(
-					"*** error for object %p: pointer being realloc'd was not allocated\n"
-					"*** set a breakpoint in malloc_error_break to debug\n",
-					old_ptr);
-			malloc_error_break();
-			if ((malloc_debug_flags & (MALLOC_ABORT_ON_CORRUPTION | MALLOC_ABORT_ON_ERROR))) {
-				_SIMPLE_STRING b = _simple_salloc();
-				if (b) {
-					_simple_sprintf(b, "*** error for object %p: pointer being realloc'd was not allocated\n", old_ptr);
-					_os_set_crash_log_message_dynamic(_simple_string(b));
-				} else {
-					_os_set_crash_log_message("*** error: pointer being realloc'd was not allocated\n");
-				}
-				abort();
+			int flags = MALLOC_REPORT_DEBUG | MALLOC_REPORT_NOLOG;
+			if (malloc_debug_flags & (MALLOC_ABORT_ON_CORRUPTION | MALLOC_ABORT_ON_ERROR)) {
+				flags = MALLOC_REPORT_CRASH | MALLOC_REPORT_NOLOG;
 			}
+			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);
 		}
 	}
+
 	if (retval == NULL) {
-		errno = ENOMEM;
+		malloc_set_errno_fast(MZ_POSIX, ENOMEM);
 	} else if (new_size == 0) {
 		free(in_ptr);
 	}
@@ -1720,13 +2234,7 @@
 void *
 valloc(size_t size)
 {
-	void *retval;
-	malloc_zone_t *zone = default_zone;
-	retval = malloc_zone_valloc(zone, size);
-	if (retval == NULL) {
-		errno = ENOMEM;
-	}
-	return retval;
+	return _malloc_zone_valloc(default_zone, size, MZ_POSIX);
 }
 
 extern void
@@ -1744,7 +2252,7 @@
 		return size;
 	}
 
-	(void)find_registered_zone(ptr, &size);
+	(void)find_registered_zone(ptr, &size, false);
 	return size;
 }
 
@@ -1795,11 +2303,52 @@
 	}
 }
 
+boolean_t
+malloc_claimed_address(void *ptr)
+{
+	// We need to check with each registered zone whether it claims "ptr".
+	// Use logic similar to that in find_registered_zone().
+	if (malloc_num_zones == 0) {
+		return false;
+	}
+
+	// Start with the lite zone, if it's in use.
+	if (lite_zone && malloc_zone_claimed_address(lite_zone, ptr)) {
+		return true;
+	}
+
+	// Next, try the initial zones.
+	for (uint32_t i = 0; i < initial_num_zones; i++) {
+		if (malloc_zone_claimed_address(malloc_zones[i], ptr)) {
+			return true;
+		}
+	}
+
+	// Try all the other zones. Increment the FRZ barrier so that we can
+	// walk the zones array without a lock (see find_registered_zone() for
+	// the details).
+	int32_t volatile *pFRZCounter = pFRZCounterLive;
+	OSAtomicIncrement32Barrier(pFRZCounter);
+
+	int32_t limit = *(int32_t volatile *)&malloc_num_zones;
+	boolean_t result = false;
+	for (uint32_t i = initial_num_zones; i < limit; i++) {
+		malloc_zone_t *zone = malloc_zones[i];
+		if (malloc_zone_claimed_address(zone, ptr)) {
+			result = true;
+			break;
+		}
+	}
+
+	OSAtomicDecrement32Barrier(pFRZCounter);
+	return result;
+}
+
 void *
 reallocarray(void * in_ptr, size_t nmemb, size_t size){
 	size_t alloc_size;
 	if (os_mul_overflow(nmemb, size, &alloc_size)){
-		errno = ENOMEM;
+		malloc_set_errno_fast(MZ_POSIX, ENOMEM);
 		return NULL;
 	}
 	return realloc(in_ptr, alloc_size);
@@ -1809,7 +2358,7 @@
 reallocarrayf(void * in_ptr, size_t nmemb, size_t size){
 	size_t alloc_size;
 	if (os_mul_overflow(nmemb, size, &alloc_size)){
-		errno = ENOMEM;
+		malloc_set_errno_fast(MZ_POSIX, ENOMEM);
 		return NULL;
 	}
 	return reallocf(in_ptr, alloc_size);
@@ -1829,7 +2378,7 @@
 	 * and only search those.
 	 */
 	size_t size = 0;
-	malloc_zone_t *zone = find_registered_zone(ptr, &size);
+	malloc_zone_t *zone = find_registered_zone(ptr, &size, false);
 
 	/* FIXME: would really like a zone->introspect->flags->purgeable check, but haven't determined
 	 * binary compatibility impact of changing the introspect struct yet. */
@@ -1884,111 +2433,7 @@
 	// <rdar://problem/25063714>
 }
 
-#if ENABLE_MEMORY_RESOURCE_EXCEPTION_HANDLING
-
-// Is the system elible to turn on/off MSL lite in response to memory resource exceptions
-//
-// Return true if
-// - The user has not explicitly opted out
-//     and
-// - Either the user has explicitly opted in or this is an Apple Internal enabled build
-
-static boolean_t
-check_is_eligible_for_lite_mode_mre_handling(void)
-{
-	struct stat stat_buf;
-		
-	// User opted out
-	if (stat("/var/db/disableLiteModeMemoryResourceExceptionHandling", &stat_buf) == 0) {
-		return false;
-	}
-	
-	// User opted in
-	if (stat("/var/db/enableLiteModeMemoryResourceExceptionHandling", &stat_buf) == 0) {
-		return true;
-	}
-	
-	
-	// Not enabled for everything else
-	return false;
-}
-
-// Not thread-safe, but it's called from malloc_memory_event_handler which already assumes
-// single thread execution.
-static boolean_t
-is_eligible_for_lite_mode_mre_handling(void)
-{
-	static boolean_t is_eligible = false;
-	static boolean_t needs_check = true;
-	
-	if (needs_check) {
-		is_eligible = check_is_eligible_for_lite_mode_mre_handling();
-		needs_check = false;
-	}
-	
-	return is_eligible;
-}
-
-#endif
-
-static void
-handle_msl_memory_event(unsigned long event)
-{
-	// don't mix and match enabling mechanisms
-	if (warn_mode_entered) {
-		return;
-	}
-	
-	event &= NOTE_MEMORYSTATUS_MSL_STATUS;
-	
-	// sanity check
-	if (event == 0) {
-		return;
-	}
-	
-	// first check if the disable bit is set
-	if (event & MEMORYSTATUS_DISABLE_MSL) {
-		turn_off_stack_logging();
-		return;
-	}
-	
-	boolean_t msl_malloc = (event & MEMORYSTATUS_ENABLE_MSL_MALLOC);
-	boolean_t msl_vm = (event & MEMORYSTATUS_ENABLE_MSL_VM);
-	boolean_t msl_lite = (event & MEMORYSTATUS_ENABLE_MSL_LITE);
-	
-	// The following always checks to make it's not possible to enable two different modes
-	// For instance this would not be allowed:
-	// Enable lite
-	// Disable
-	// Enable full
-	
-	// Currently there is no separation of malloc/vm in lite mode
-	if (msl_lite) {
-		if (msl_type_enabled_at_runtime == stack_logging_mode_none || msl_type_enabled_at_runtime == stack_logging_mode_lite) {
-			msl_type_enabled_at_runtime = stack_logging_mode_lite;
-			turn_on_stack_logging(stack_logging_mode_lite);
-		}
-		return;
-	} else if (msl_malloc && msl_vm) {
-		if (msl_type_enabled_at_runtime == stack_logging_mode_none || msl_type_enabled_at_runtime == stack_logging_mode_all) {
-			msl_type_enabled_at_runtime = stack_logging_mode_all;
-			turn_on_stack_logging(stack_logging_mode_all);
-		}
-		return;
-	} else if (msl_malloc) {
-		if (msl_type_enabled_at_runtime == stack_logging_mode_none || msl_type_enabled_at_runtime == stack_logging_mode_malloc) {
-			msl_type_enabled_at_runtime = stack_logging_mode_malloc;
-			turn_on_stack_logging(stack_logging_mode_malloc);
-		}
-		return;
-	} else if (msl_vm) {
-		if (msl_type_enabled_at_runtime == stack_logging_mode_none || msl_type_enabled_at_runtime == stack_logging_mode_vm) {
-			msl_type_enabled_at_runtime = stack_logging_mode_vm;
-			turn_on_stack_logging(stack_logging_mode_vm);
-		}
-		return;
-	}
-}
+
 
 // Note that malloc_memory_event_handler is not thread-safe, and we are relying on the callers of this for synchronization
 void
@@ -1997,52 +2442,21 @@
 	if (event & NOTE_MEMORYSTATUS_PRESSURE_WARN) {
 		malloc_zone_pressure_relief(0, 0);
 	}
+
+	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 & (NOTE_MEMORYSTATUS_PROC_LIMIT_WARN | NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL | NOTE_MEMORYSTATUS_PRESSURE_CRITICAL)) {
+		malloc_register_stack_logger();
+	}
+#endif // ENABLE_MEMORY_RESOURCE_EXCEPTION_HANDLING
 	
-	// First check for enable/disable MSL - only recognize if all other bits are 0
-	// Don't attempt this if we've either entered or exited MRE mode
-	if ((event & NOTE_MEMORYSTATUS_MSL_STATUS) != 0 && (event & ~NOTE_MEMORYSTATUS_MSL_STATUS) == 0 && !warn_mode_entered && !warn_mode_disable_retries) {
-		handle_msl_memory_event(event);
-		return;
-	}
-
-#if ENABLE_MEMORY_RESOURCE_EXCEPTION_HANDLING
-	// If we have reached EXC_RESOURCE, we no longer need stack log data.
-	// If we are under system-wide memory pressure, we should jettison stack log data.
-	if ((event & (NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL | NOTE_MEMORYSTATUS_PRESSURE_CRITICAL)) &&
-		!warn_mode_disable_retries) {
-		// If we have crossed the EXC_RESOURCE limit once already, there is no point in
-		// collecting stack logs in the future, even if we missed a previous chance to
-		// collect data because nobody is going to ask us for it again.
-		warn_mode_disable_retries = true;
-
-		// Only try to clean up stack log data if it was enabled through a proc limit warning.
-		// User initiated stack logging should proceed unimpeded.
-		if (warn_mode_entered) {
-			malloc_printf("malloc_memory_event_handler: stopping stack-logging\n");
-			turn_off_stack_logging();
-			__malloc_lock_stack_logging();
-			__delete_uniquing_table_memory_while_locked();
-			__malloc_unlock_stack_logging();
-			
-			warn_mode_entered = false;
-		}
-	}
-
-	// Enable stack logging if we are approaching the process limit, provided
-	// we aren't under system wide memory pressure and we're allowed to try again.
-	if ((event & NOTE_MEMORYSTATUS_PROC_LIMIT_WARN) &&
-		!(event & NOTE_MEMORYSTATUS_PRESSURE_CRITICAL) &&
-		!warn_mode_entered && !warn_mode_disable_retries &&
-		is_eligible_for_lite_mode_mre_handling()) {
-		malloc_printf("malloc_memory_event_handler: approaching memory limit. Starting stack-logging.\n");
-		if (turn_on_stack_logging(stack_logging_mode_lite)) {
-			warn_mode_entered = true;
-			
-			// set the maximum allocation threshold
-			max_lite_mallocs = MAX_LITE_MALLOCS;
-		}
-	}
-#endif
+	if (msl.handle_memory_event) {
+		// Let MSL see the event.
+		msl.handle_memory_event(event);
+	}
 }
 
 size_t
@@ -2092,12 +2506,12 @@
 	if (!zone->batch_malloc) {
 		return 0;
 	}
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	if (malloc_check_start) {
 		internal_check();
 	}
 	unsigned batched = zone->batch_malloc(zone, size, results, num_requested);
 	
-	if (malloc_logger) {
+	if (os_unlikely(malloc_logger)) {
 		unsigned index = 0;
 		while (index < batched) {
 			malloc_logger(MALLOC_LOG_TYPE_ALLOCATE | MALLOC_LOG_TYPE_HAS_ZONE, (uintptr_t)zone, (uintptr_t)size, 0,
@@ -2111,10 +2525,10 @@
 void
 malloc_zone_batch_free(malloc_zone_t *zone, void **to_be_freed, unsigned num)
 {
-	if (malloc_check_start && (malloc_check_counter++ >= malloc_check_start)) {
+	if (malloc_check_start) {
 		internal_check();
 	}
-	if (malloc_logger) {
+	if (os_unlikely(malloc_logger)) {
 		unsigned index = 0;
 		while (index < num) {
 			malloc_logger(
@@ -2136,13 +2550,6 @@
 }
 
 /*********	Functions for performance tools	************/
-
-static kern_return_t
-_malloc_default_reader(task_t task, vm_address_t address, vm_size_t size, void **ptr)
-{
-	*ptr = (void *)address;
-	return 0;
-}
 
 kern_return_t
 malloc_get_all_zones(task_t task, memory_reader_t reader, vm_address_t **addresses, unsigned *count)
@@ -2163,14 +2570,14 @@
 	err = reader(task, remote_malloc_zones, sizeof(void *), (void **)&zones_address_ref);
 	// printf("Read malloc_zones[%p]=%p\n", remote_malloc_zones, *zones_address_ref);
 	if (err) {
-		malloc_printf("*** malloc_get_all_zones: error reading zones_address at %p\n", (unsigned)remote_malloc_zones);
+		malloc_report(ASL_LEVEL_ERR, "*** malloc_get_all_zones: error reading zones_address at %p\n", (void *)remote_malloc_zones);
 		return err;
 	}
 	zones_address = *zones_address_ref;
 	// printf("Reading num_zones at address %p\n", remote_malloc_num_zones);
 	err = reader(task, remote_malloc_num_zones, sizeof(unsigned), (void **)&num_zones_ref);
 	if (err) {
-		malloc_printf("*** malloc_get_all_zones: error reading num_zones at %p\n", (unsigned)remote_malloc_num_zones);
+		malloc_report(ASL_LEVEL_ERR, "*** malloc_get_all_zones: error reading num_zones at %p\n", (void *)remote_malloc_num_zones);
 		return err;
 	}
 	num_zones = *num_zones_ref;
@@ -2179,7 +2586,7 @@
 	// printf("malloc_get_all_zones succesfully found %d zones\n", num_zones);
 	err = reader(task, zones_address, sizeof(malloc_zone_t *) * num_zones, (void **)addresses);
 	if (err) {
-		malloc_printf("*** malloc_get_all_zones: error reading zones at %p\n", &zones_address);
+		malloc_report(ASL_LEVEL_ERR, "*** malloc_get_all_zones: error reading zones at %p\n", &zones_address);
 		return err;
 	}
 	// printf("malloc_get_all_zones succesfully read %d zones\n", num_zones);
@@ -2271,20 +2678,29 @@
 
 /*********	Misc other entry points	************/
 
+void
+mag_set_thread_index(unsigned int index)
+{
+	_os_cpu_number_override = index;
+#if CONFIG_NANOZONE
+	nano_common_cpu_number_override_set();
+#endif // CONFIG_NANOZONE
+}
+
 static void
 DefaultMallocError(int x)
 {
 #if USE_SLEEP_RATHER_THAN_ABORT
-	malloc_printf("*** error %d\n", x);
+	malloc_report(ASL_LEVEL_ERR, "*** error %d\n", x);
 	sleep(3600);
 #else
 	_SIMPLE_STRING b = _simple_salloc();
 	if (b) {
 		_simple_sprintf(b, "*** error %d", x);
-		malloc_printf("%s\n", _simple_string(b));
+		malloc_report(MALLOC_REPORT_NOLOG, "%s\n", _simple_string(b));
 		_os_set_crash_log_message_dynamic(_simple_string(b));
 	} else {
-		_malloc_printf(MALLOC_PRINTF_NOLOG, "*** error %d", x);
+		malloc_report(MALLOC_REPORT_NOLOG, "*** error %d\n", x);
 		_os_set_crash_log_message("*** DefaultMallocError called");
 	}
 	abort();
@@ -2305,14 +2721,18 @@
 		malloc_zone_t *zone = malloc_zones[index++];
 		zone->introspect->force_lock(zone);
 	}
-	callout();
+	if (callout) {
+		callout();
+	}
 }
 
 static void
 _malloc_unlock_all(void (*callout)(void))
 {
 	unsigned index = 0;
-	callout();
+	if (callout) {
+		callout();
+	}
 	while (index < malloc_num_zones) {
 		malloc_zone_t *zone = malloc_zones[index++];
 		zone->introspect->force_unlock(zone);
@@ -2324,7 +2744,9 @@
 _malloc_reinit_lock_all(void (*callout)(void))
 {
 	unsigned index = 0;
-	callout();
+	if (callout) {
+		callout();
+	}
 	while (index < malloc_num_zones) {
 		malloc_zone_t *zone = malloc_zones[index++];
 		if (zone->version < 9) { // Version must be >= 9 to look at reinit_lock
@@ -2343,14 +2765,14 @@
 void
 _malloc_fork_prepare(void)
 {
-	return _malloc_lock_all(&__stack_logging_fork_prepare);
+	return _malloc_lock_all(msl.fork_prepare);
 }
 
 // Called in the parent process after fork() to resume normal operation.
 void
 _malloc_fork_parent(void)
 {
-	return _malloc_unlock_all(&__stack_logging_fork_parent);
+	return _malloc_unlock_all(msl.fork_parent);
 }
 
 // Called in the child process after fork() to resume normal operation.
@@ -2358,11 +2780,13 @@
 _malloc_fork_child(void)
 {
 #if CONFIG_NANOZONE
-	if (_malloc_initialize_pred && _malloc_engaged_nano) {
-		nano_forked_zone((nanozone_t *)inline_malloc_default_zone());
+	if (_malloc_entropy_initialized) {
+		if (_malloc_engaged_nano == NANO_V2) {
+			nanov2_forked_zone((nanozonev2_t *)initial_nano_zone);
+		}
 	}
 #endif
-	return _malloc_reinit_lock_all(&__stack_logging_fork_child);
+	return _malloc_reinit_lock_all(msl.fork_child);
 }
 
 /*
@@ -2456,6 +2880,12 @@
 	}
 }
 
+void
+malloc_zero_on_free_disable(void)
+{
+	malloc_zero_policy = MALLOC_ZERO_NONE;
+}
+
 /*****************	OBSOLETE ENTRY POINTS	********************/
 
 #if PHASE_OUT_OLD_MALLOC
@@ -2468,7 +2898,7 @@
 	static boolean_t warned = 0;
 	if (!warned) {
 #if PHASE_OUT_OLD_MALLOC
-		malloc_printf("*** OBSOLETE: set_malloc_singlethreaded(%d)\n", single);
+		malloc_report(ASL_LEVEL_ERR, "*** OBSOLETE: set_malloc_singlethreaded(%d)\n", single);
 #endif
 		warned = 1;
 	}
@@ -2479,7 +2909,7 @@
 {
 	static boolean_t warned = 0;
 	if (!warned) {
-		malloc_printf("*** OBSOLETE: malloc_singlethreaded()\n");
+		malloc_report(ASL_LEVEL_ERR, "*** OBSOLETE: malloc_singlethreaded()\n");
 		warned = 1;
 	}
 }
@@ -2487,8 +2917,401 @@
 int
 malloc_debug(int level)
 {
-	malloc_printf("*** OBSOLETE: malloc_debug()\n");
+	malloc_report(ASL_LEVEL_ERR, "*** OBSOLETE: malloc_debug()\n");
 	return 0;
 }
 
+#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
+stack_logging_early_finished(const struct _malloc_late_init *funcs)
+{
+#if !TARGET_OS_DRIVERKIT
+	_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);
+			}
+			break;
+		}
+	}
+	if (msl.initialize) {
+		msl.initialize();
+	}
+}
+
+
+static os_once_t _register_msl_dylib_pred;
+
+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.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");
+
+	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_quarantine_enabled && !at_startup) {
+		return false;
+	}
+#if !TARGET_OS_DRIVERKIT
+	if (msl.handle_memory_event != NULL) {
+		return true;
+	}
+	if (_dlopen == NULL) {
+		return false;
+	}
+	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) {
+		malloc_report(ASL_LEVEL_WARNING, "failed to load MallocStackLogging.framework\n");
+		return false;
+	}
+	return true;
+}
+
+/* Symbolication.framework looks up this symbol by name inside libsystem_malloc.dylib. */
+uint64_t __mach_stack_logging_shared_memory_address = 0;
+
+
+#pragma mark -
+#pragma mark Malloc Stack Logging - Legacy stubs
+
+/*
+ * legacy API for MallocStackLogging.
+ *
+ * TODO, deprecate this, move clients off it and delete it.   Clients should move
+ * to MallocStackLogging.framework for these APIs.
+ */
+
+MALLOC_EXPORT
+boolean_t
+turn_on_stack_logging(stack_logging_mode_type mode)
+{
+	malloc_register_stack_logger();
+	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
+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) {
+		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");
+	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) {
+		return KERN_FAILURE;
+	}
+	kern_return_t (*f) (task_t task);
+	f = _dlsym(msld.dylib, "msl_stop_reading");
+	if (!f) {
+		return KERN_FAILURE;
+	}
+	return f(task);
+}
+
+kern_return_t
+__mach_stack_logging_get_frames(task_t task,
+								mach_vm_address_t address,
+								mach_vm_address_t *stack_frames_buffer,
+								uint32_t max_stack_frames,
+								uint32_t *count)
+{
+	malloc_register_stack_logger();
+	if (!msld.get_frames_for_address) {
+		return KERN_FAILURE;
+	}
+	return msld.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) {
+		return -1ull;
+	}
+	return msld.stackid_for_vm_region(task, address);
+}
+
+//deprecated
+kern_return_t
+__mach_stack_logging_frames_for_uniqued_stack(task_t task,
+											  uint64_t stack_identifier,
+											  mach_vm_address_t *stack_frames_buffer,
+											  uint32_t max_stack_frames,
+											  uint32_t *count)
+{
+	malloc_register_stack_logger();
+	if (!msld.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
+kern_return_t
+__mach_stack_logging_get_frames_for_stackid(task_t task,
+											uint64_t stack_identifier,
+											mach_vm_address_t *stack_frames_buffer,
+											uint32_t max_stack_frames,
+											uint32_t *count,
+											bool *last_frame_is_threadid)
+{
+	malloc_register_stack_logger();
+	if (!msld.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
+kern_return_t
+__mach_stack_logging_uniquing_table_read_stack(struct backtrace_uniquing_table *uniquing_table,
+											   uint64_t stackid,
+											   mach_vm_address_t *out_frames_buffer,
+											   uint32_t *out_frames_count,
+											   uint32_t max_frames)
+{
+	malloc_register_stack_logger();
+	if (!msld.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
+kern_return_t
+__mach_stack_logging_enumerate_records(task_t task,
+									   mach_vm_address_t address,
+									   void enumerator(mach_stack_logging_record_t, void *),
+									   void *context)
+{
+	malloc_register_stack_logger();
+	kern_return_t (*f) (task_t task,
+						mach_vm_address_t address,
+						void enumerator(mach_stack_logging_record_t, void *),
+						void *context);
+	if (!msld.dylib) {
+		return KERN_FAILURE;
+	}
+	f = _dlsym(msld.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) {
+		return NULL;
+	}
+	f = _dlsym(msld.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) {
+		return NULL;
+	}
+	f = _dlsym(msld.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) {
+		return;
+	}
+	void (*f) (struct backtrace_uniquing_table *table);
+	f = _dlsym(msld.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) {
+		return;
+	}
+	void (*f) (struct backtrace_uniquing_table *table);
+	f = _dlsym(msld.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");
+	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) {
+		return NULL;
+	}
+	void * (*f) (struct backtrace_uniquing_table *table, mach_vm_size_t *size);
+	f = _dlsym(msld.dylib, "msl_uniquing_table_serialize");
+	if (!f) {
+		return NULL;
+	}
+	return f(table, size);
+}
+
+kern_return_t
+__mach_stack_logging_set_file_path(task_t task, char* file_path)
+{
+	return KERN_SUCCESS;
+}
+
+/* WeChat references this, only god knows why.  This symbol does nothing. */
+int stack_logging_enable_logging = 0;
+
 /* vim: set noet:ts=4:sw=4:cindent: */