--- libmalloc/libmalloc-409.40.6/src/malloc_printf.c
+++ libmalloc/libmalloc-283/src/malloc_printf.c
@@ -48,9 +48,8 @@
 }
 
 #define WRITE_TO_DEBUG_FILE(flags) \
-		(((flags) & MALLOC_REPORT_NOWRITE) == 0 && \
 		((debug_mode == DEBUG_WRITE_ALWAYS) || \
-		(debug_mode == DEBUG_WRITE_ON_CRASH && ((flags) & MALLOC_REPORT_CRASH))))
+		(debug_mode == DEBUG_WRITE_ON_CRASH && (flags & MALLOC_REPORT_CRASH)))
 #define	MALLOC_REPORT_LEVEL_MASK	0x0f
 
 #pragma mark -
@@ -99,7 +98,7 @@
 	if ((b = _simple_salloc()) == NULL) {
 		if (WRITE_TO_DEBUG_FILE(flags)) {
 			if (!(flags & MALLOC_REPORT_NOPREFIX)) {
-				void *self = _pthread_self_direct();
+				void *self = _os_tsd_get_direct(__TSD_THREAD_SELF);
 				_simple_dprintf(malloc_debug_file, "%s(%d,%p) malloc: ", getprogname(), getpid(), self);
 			}
 			write(malloc_debug_file, msg, strlen(msg));
@@ -107,7 +106,7 @@
 		return;
 	}
 	if (!(flags & MALLOC_REPORT_NOPREFIX)) {
-		void *self = _pthread_self_direct();
+		void *self = _os_tsd_get_direct(__TSD_THREAD_SELF);
 		_simple_sprintf(b, "%s(%d,%p) malloc: ", getprogname(), getpid(), self);
 	}
 
@@ -123,37 +122,6 @@
 
 #pragma mark -
 #pragma mark High-Level Reporting Functions
-
-#define MALLOC_BT_DEPTH 50
-
-static void
-_malloc_append_backtrace(_SIMPLE_STRING b)
-{
-	void *btarray[MALLOC_BT_DEPTH];
-
-	int count = backtrace(btarray, MALLOC_BT_DEPTH);
-	if (!count) {
-		return;
-	}
-
-	struct image_offset bt_image_offsets[MALLOC_BT_DEPTH];
-	backtrace_image_offsets(btarray, bt_image_offsets, count);
-
-	uuid_t last_uuid;
-	for (int i = 0; i < count; i++) {
-		// simple de-duping for runs of UUIDs common in backtraces
-		if (i == 0 || uuid_compare(last_uuid, bt_image_offsets[i].uuid) != 0) {
-			uuid_copy(last_uuid, bt_image_offsets[i].uuid);
-
-			uuid_string_t uus;
-			uuid_unparse(bt_image_offsets[i].uuid, uus);
-			_simple_sappend(b, uus);
-		} else {
-			_simple_sappend(b, "last");
-		}
-		_simple_sprintf(b, "+%u,", bt_image_offsets[i].offset);
-	}
-}
 
 MALLOC_NOINLINE void
 malloc_vreport(uint32_t flags, unsigned sleep_time, const char *prefix_msg,
@@ -164,7 +132,7 @@
 	if ((b = _simple_salloc()) == NULL) {
 		if (WRITE_TO_DEBUG_FILE(flags)) {
 			if (!(flags & MALLOC_REPORT_NOPREFIX)) {
-				void *self = _pthread_self_direct();
+				void *self = _os_tsd_get_direct(__TSD_THREAD_SELF);
 				_simple_dprintf(malloc_debug_file, "%s(%d,%p) malloc: ", getprogname(), getpid(), self);
 			}
 			if (prefix_msg) {
@@ -177,18 +145,13 @@
 		}
 	} else {
 		if (!(flags & MALLOC_REPORT_NOPREFIX)) {
-			void *self = _pthread_self_direct();
+			void *self = _os_tsd_get_direct(__TSD_THREAD_SELF);
 			_simple_sprintf(b, "%s(%d,%p) malloc: ", getprogname(), getpid(), self);
 		}
 		if (prefix_msg) {
 			_simple_sprintf(b, prefix_msg, prefix_arg);
 		}
 		_simple_vsprintf(b, fmt, ap);
-
-		if (flags & MALLOC_REPORT_BACKTRACE) {
-			_malloc_append_backtrace(b);
-		}
-
 		if (WRITE_TO_DEBUG_FILE(flags)) {
 			_simple_put(b, malloc_debug_file);
 		}
@@ -243,8 +206,6 @@
 #pragma mark -
 #pragma mark Zone Error Reporing
 
-#ifndef MALLOC_BUILDING_XCTESTS
-
 void
 malloc_zone_error(uint32_t flags, bool is_corruption, const char *fmt, ...)
 {
@@ -259,8 +220,6 @@
 			NULL, NULL, fmt, ap);
 	va_end(ap);
 }
-
-#endif // MALLOC_BUILDING_XCTESTS
 
 #pragma mark -
 #pragma mark Malloc Output API.