gen/thread_stack_pcs.c

   1 /*
   2  * Copyright (c) 1999-2018 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*      Bertrand from vmutils -> CF -> System */
  25
  26 #include <pthread.h>
  27 #include <mach/mach.h>
  28 #include <mach/vm_statistics.h>
  29 #include <stdlib.h>
  30 #include "stack_logging.h"
  31
  32
  33 #if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__arm64__)
  34 #define FP_LINK_OFFSET 1
  35 #else
  36 #error ********** Unimplemented architecture
  37 #endif
  38
  39
  40 #define INSTACK(a)      ((a) >= stackbot && (a) <= stacktop)
  41 #if defined(__x86_64__)
  42 #define ISALIGNED(a)    ((((uintptr_t)(a)) & 0xf) == 0)
  43 #elif defined(__i386__)
  44 #define ISALIGNED(a)    ((((uintptr_t)(a)) & 0xf) == 8)
  45 #elif defined(__arm__) || defined(__arm64__)
  46 #define ISALIGNED(a)    ((((uintptr_t)(a)) & 0x1) == 0)
  47 #endif
  48
  49 __private_extern__  __attribute__((noinline))
  50 void
  51 _thread_stack_pcs(vm_address_t *buffer, unsigned max, unsigned *nb,
  52                 unsigned skip, void *startfp)
  53 {
  54         void *frame, *next;
  55         pthread_t self = pthread_self();
  56         void *stacktop = pthread_get_stackaddr_np(self);
  57         void *stackbot = stacktop - pthread_get_stacksize_np(self);
  58
  59         *nb = 0;
  60
  61         /* make sure return address is never out of bounds */
  62         stacktop -= (FP_LINK_OFFSET + 1) * sizeof(void *);
  63
  64         frame = __builtin_frame_address(0);
  65         if(!INSTACK(frame) || !ISALIGNED(frame))
  66                 return;
  67         while ((startfp && startfp >= *(void **)frame) || skip--) {
  68                 next = *(void **)frame;
  69                 if(!INSTACK(next) || !ISALIGNED(next) || next <= frame)
  70                         return;
  71                 frame = next;
  72         }
  73         while (max--) {
  74                 void *retaddr = (void *)*(vm_address_t *)
  75                                 (((void **)frame) + FP_LINK_OFFSET);
  76 #pragma clang diagnostic push
  77 #pragma clang diagnostic ignored "-Wint-conversion"
  78                 buffer[*nb] = retaddr;
  79 #pragma clang diagnostic pop
  80                 (*nb)++;
  81                 next = *(void **)frame;
  82                 if(!INSTACK(next) || !ISALIGNED(next) || next <= frame)
  83                         return;
  84                 frame = next;
  85         }
  86 }
  87
  88 // Prevent thread_stack_pcs() from getting tail-call-optimized into
  89 // _thread_stack_pcs() on 64-bit environments, thus making the "number of hot
  90 // frames to skip" be more predictable, giving more consistent backtraces.
  91 //
  92 // See <rdar://problem/5364825> "stack logging: frames keep getting truncated"
  93 // for why this is necessary.
  94 __attribute__((disable_tail_calls))
  95 void
  96 thread_stack_pcs(vm_address_t *buffer, unsigned max, unsigned *nb)
  97 {
  98         _thread_stack_pcs(buffer, max, nb, 0, NULL);
  99 }