--- /dev/null
+++ Libc/Libc-1353.11.2/gen/thread_stack_pcs.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 1999-2018 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+/*	Bertrand from vmutils -> CF -> System */
+
+#include <pthread.h>
+#include <mach/mach.h>
+#include <mach/vm_statistics.h>
+#include <stdlib.h>
+#include <pthread/stack_np.h>
+#include "stack_logging.h"
+
+#define	INSTACK(a)	((a) >= stackbot && (a) <= stacktop)
+#if defined(__x86_64__)
+#define	ISALIGNED(a)	((((uintptr_t)(a)) & 0xf) == 0)
+#elif defined(__i386__)
+#define	ISALIGNED(a)	((((uintptr_t)(a)) & 0xf) == 8)
+#elif defined(__arm__) || defined(__arm64__)
+#define	ISALIGNED(a)	((((uintptr_t)(a)) & 0x1) == 0)
+#endif
+
+__attribute__((noinline))
+static void
+__thread_stack_pcs(vm_address_t *buffer, unsigned max, unsigned *nb,
+		unsigned skip, void *startfp)
+{
+	void *frame, *next;
+	pthread_t self = pthread_self();
+	void *stacktop = pthread_get_stackaddr_np(self);
+	void *stackbot = stacktop - pthread_get_stacksize_np(self);
+
+	*nb = 0;
+
+	// Rely on the fact that our caller has an empty stackframe (no local vars)
+	// to determine the minimum size of a stackframe (frame ptr & return addr)
+	frame = __builtin_frame_address(0);
+	next = (void*)pthread_stack_frame_decode_np((uintptr_t)frame, NULL);
+
+	/* make sure return address is never out of bounds */
+	stacktop -= (next - frame);
+
+	if(!INSTACK(frame) || !ISALIGNED(frame))
+		return;
+	while (startfp || skip--) {
+		if (startfp && startfp < next) break;
+		if(!INSTACK(next) || !ISALIGNED(next) || next <= frame)
+			return;
+		frame = next;
+		next = (void*)pthread_stack_frame_decode_np((uintptr_t)frame, NULL);
+	}
+	while (max--) {
+		uintptr_t retaddr;
+		next = (void*)pthread_stack_frame_decode_np((uintptr_t)frame, &retaddr);
+		buffer[*nb] = retaddr;
+		(*nb)++;
+		if(!INSTACK(next) || !ISALIGNED(next) || next <= frame)
+			return;
+		frame = next;
+	}
+}
+
+// Note that callee relies on this function having a minimal stackframe
+// to introspect (i.e. no tailcall and no local variables)
+__private_extern__ __attribute__((disable_tail_calls))
+void
+_thread_stack_pcs(vm_address_t *buffer, unsigned max, unsigned *nb,
+		unsigned skip, void *startfp)
+{
+	// skip this frame
+	__thread_stack_pcs(buffer, max, nb, skip + 1, startfp);
+}
+
+// Prevent thread_stack_pcs() from getting tail-call-optimized into
+// __thread_stack_pcs() on 64-bit environments, thus making the "number of hot
+// frames to skip" be more predictable, giving more consistent backtraces.
+//
+// See <rdar://problem/5364825> "stack logging: frames keep getting truncated"
+// for why this is necessary.
+//
+// Note that callee relies on this function having a minimal stackframe
+// to introspect (i.e. no tailcall and no local variables)
+__attribute__((disable_tail_calls))
+void
+thread_stack_pcs(vm_address_t *buffer, unsigned max, unsigned *nb)
+{
+	__thread_stack_pcs(buffer, max, nb, 0, NULL);
+}