third_party/tcmalloc/chromium/src/stacktrace_libunwind-inl.h

   1 // Copyright (c) 2005, Google Inc.
   2 // All rights reserved.
   3 //
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   5 // modification, are permitted provided that the following conditions are
   6 // met:
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   9 // notice, this list of conditions and the following disclaimer.
  10 //     * Redistributions in binary form must reproduce the above
  11 // copyright notice, this list of conditions and the following disclaimer
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  15 // contributors may be used to endorse or promote products derived from
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  17 //
  18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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  24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29
  30 // ---
  31 // Author: Arun Sharma
  32 //
  33 // Produce stack trace using libunwind
  34
  35 #ifndef BASE_STACKTRACE_LIBINWIND_INL_H_
  36 #define BASE_STACKTRACE_LIBINWIND_INL_H_
  37 // Note: this file is included into stacktrace.cc more than once.
  38 // Anything that should only be defined once should be here:
  39
  40 // We only need local unwinder.
  41 #define UNW_LOCAL_ONLY
  42
  43 extern "C" {
  44 #include <assert.h>
  45 #include <string.h>   // for memset()
  46 #include <libunwind.h>
  47 }
  48 #include "gperftools/stacktrace.h"
  49 #include "base/logging.h"
  50
  51 // Sometimes, we can try to get a stack trace from within a stack
  52 // trace, because libunwind can call mmap (maybe indirectly via an
  53 // internal mmap based memory allocator), and that mmap gets trapped
  54 // and causes a stack-trace request.  If were to try to honor that
  55 // recursive request, we'd end up with infinite recursion or deadlock.
  56 // Luckily, it's safe to ignore those subsequent traces.  In such
  57 // cases, we return 0 to indicate the situation.
  58 static __thread int recursive;
  59
  60 #endif  // BASE_STACKTRACE_LIBINWIND_INL_H_
  61
  62 // Note: this part of the file is included several times.
  63 // Do not put globals below.
  64
  65 // The following 4 functions are generated from the code below:
  66 //   GetStack{Trace,Frames}()
  67 //   GetStack{Trace,Frames}WithContext()
  68 //
  69 // These functions take the following args:
  70 //   void** result: the stack-trace, as an array
  71 //   int* sizes: the size of each stack frame, as an array
  72 //               (GetStackFrames* only)
  73 //   int max_depth: the size of the result (and sizes) array(s)
  74 //   int skip_count: how many stack pointers to skip before storing in result
  75 //   void* ucp: a ucontext_t* (GetStack{Trace,Frames}WithContext only)
  76 int GET_STACK_TRACE_OR_FRAMES {
  77   void *ip;
  78   int n = 0;
  79   unw_cursor_t cursor;
  80   unw_context_t uc;
  81 #if IS_STACK_FRAMES
  82   unw_word_t sp = 0, next_sp = 0;
  83 #endif
  84
  85   if (recursive) {
  86     return 0;
  87   }
  88   ++recursive;
  89
  90   unw_getcontext(&uc);
  91   int ret = unw_init_local(&cursor, &uc);
  92   assert(ret >= 0);
  93   skip_count++;         // Do not include current frame
  94
  95   while (skip_count--) {
  96     if (unw_step(&cursor) <= 0) {
  97       goto out;
  98     }
  99 #if IS_STACK_FRAMES
 100     if (unw_get_reg(&cursor, UNW_REG_SP, &next_sp)) {
 101       goto out;
 102     }
 103 #endif
 104   }
 105
 106   while (n < max_depth) {
 107     if (unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip) < 0) {
 108       break;
 109     }
 110 #if IS_STACK_FRAMES
 111     sizes[n] = 0;
 112 #endif
 113     result[n++] = ip;
 114     if (unw_step(&cursor) <= 0) {
 115       break;
 116     }
 117 #if IS_STACK_FRAMES
 118     sp = next_sp;
 119     if (unw_get_reg(&cursor, UNW_REG_SP, &next_sp) , 0) {
 120       break;
 121     }
 122     sizes[n - 1] = next_sp - sp;
 123 #endif
 124   }
 125 out:
 126   --recursive;
 127   return n;
 128 }