--- Libc/Libc-1353.100.2/gen/thread_stack_pcs.c
+++ Libc/Libc-498/gen/thread_stack_pcs.c
@@ -1,15 +1,15 @@
 /*
- * Copyright (c) 1999-2018 Apple Inc. All rights reserved.
+ * Copyright (c) 1999, 2007 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,
@@ -17,7 +17,7 @@
  * 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@
  */
 
@@ -27,81 +27,82 @@
 #include <mach/mach.h>
 #include <mach/vm_statistics.h>
 #include <stdlib.h>
-#include <pthread/stack_np.h>
-#include "stack_logging.h"
+
+#if defined(__i386__) || defined(__x86_64__)
+#define FP_LINK_OFFSET 1
+#elif defined(__ppc__) || defined(__ppc64__)
+#define FP_LINK_OFFSET 2
+#else
+#error  ********** Unimplemented architecture
+#endif
 
 #define	INSTACK(a)	((a) >= stackbot && (a) <= stacktop)
-#if defined(__x86_64__)
+#if defined(__ppc__) || defined(__ppc64__) || 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)
+__private_extern__  __attribute__((noinline))
+void
+_thread_stack_pcs(vm_address_t *buffer, unsigned max, unsigned *nb, unsigned skip)
 {
-	void *frame, *next;
-	pthread_t self = pthread_self();
-	void *stacktop = pthread_get_stackaddr_np(self);
-	void *stackbot = stacktop - pthread_get_stacksize_np(self);
+    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;
+    *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 -= (FP_LINK_OFFSET + 1) * sizeof(void *);
 
-	/* 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;
-	}
+    /*
+     * The original implementation called the first_frame_address() function,
+     * which returned the stack frame pointer.  The problem was that in ppc,
+     * it was a leaf function, so no new stack frame was set up with
+     * optimization turned on (while a new stack frame was set up without
+     * optimization).  We now inline the code to get the stack frame pointer,
+     * so we are consistent about the stack frame.
+     */
+#if defined(__i386__) || defined(__x86_64__)
+    frame = __builtin_frame_address(0);
+#elif defined(__ppc__) || defined(__ppc64__)
+    /* __builtin_frame_address IS BROKEN IN BEAKER: RADAR #2340421 */
+    __asm__ volatile("mr %0, r1" : "=r" (frame));
+#endif
+    if(!INSTACK(frame) || !ISALIGNED(frame))
+	return;
+#if defined(__ppc__) || defined(__ppc64__)
+    /* back up the stack pointer up over the current stack frame */
+    next = *(void **)frame;
+    if(!INSTACK(next) || !ISALIGNED(next) || next <= frame)
+	return;
+    frame = next;
+#endif
+    while (skip--) {
+	next = *(void **)frame;
+	if(!INSTACK(next) || !ISALIGNED(next) || next <= frame)
+	    return;
+	frame = next;
+    }
+    while (max--) {
+        buffer[*nb] = *(vm_address_t *)(((void **)frame) + FP_LINK_OFFSET);
+        (*nb)++;
+	next = *(void **)frame;
+	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);
+    _thread_stack_pcs(buffer, max, nb, 0);
+
+    // The following prevents 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.
+    __asm__ volatile("");
 }