ceph/src/boost/boost/stacktrace/detail/collect_unwind.ipp

   1 // Copyright Antony Polukhin, 2016-2017.
   2 //
   3 // Distributed under the Boost Software License, Version 1.0. (See
   4 // accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_STACKTRACE_DETAIL_COLLECT_UNWIND_IPP
   8 #define BOOST_STACKTRACE_DETAIL_COLLECT_UNWIND_IPP
   9
  10 #include <boost/config.hpp>
  11 #ifdef BOOST_HAS_PRAGMA_ONCE
  12 #   pragma once
  13 #endif
  14
  15 #include <boost/stacktrace/safe_dump_to.hpp>
  16
  17 #include <unwind.h>
  18 #include <cstdio>
  19
  20 #if !defined(_GNU_SOURCE) && !defined(BOOST_STACKTRACE_GNU_SOURCE_NOT_REQUIRED) && !defined(BOOST_WINDOWS)
  21 #error "Boost.Stacktrace requires `_Unwind_Backtrace` function. Define `_GNU_SOURCE` macro or `BOOST_STACKTRACE_GNU_SOURCE_NOT_REQUIRED` if _Unwind_Backtrace is available without `_GNU_SOURCE`."
  22 #endif
  23
  24 namespace boost { namespace stacktrace { namespace detail {
  25
  26 struct unwind_state {
  27     std::size_t frames_to_skip;
  28     native_frame_ptr_t* current;
  29     native_frame_ptr_t* end;
  30 };
  31
  32 inline _Unwind_Reason_Code unwind_callback(::_Unwind_Context* context, void* arg) {
  33     // Note: do not write `::_Unwind_GetIP` because it is a macro on some platforms.
  34     // Use `_Unwind_GetIP` instead!
  35     unwind_state* const state = static_cast<unwind_state*>(arg);
  36     if (state->frames_to_skip) {
  37         --state->frames_to_skip;
  38         return _Unwind_GetIP(context) ? ::_URC_NO_REASON : ::_URC_END_OF_STACK;
  39     }
  40
  41     *state->current =  reinterpret_cast<native_frame_ptr_t>(
  42         _Unwind_GetIP(context)
  43     );
  44
  45     ++state->current;
  46     if (!*(state->current - 1) || state->current == state->end) {
  47         return ::_URC_END_OF_STACK;
  48     }
  49     return ::_URC_NO_REASON;
  50 }
  51
  52 std::size_t this_thread_frames::collect(native_frame_ptr_t* out_frames, std::size_t max_frames_count, std::size_t skip) BOOST_NOEXCEPT {
  53     std::size_t frames_count = 0;
  54     if (!max_frames_count) {
  55         return frames_count;
  56     }
  57
  58     boost::stacktrace::detail::unwind_state state = { skip + 1, out_frames, out_frames + max_frames_count };
  59     ::_Unwind_Backtrace(&boost::stacktrace::detail::unwind_callback, &state);
  60     frames_count = state.current - out_frames;
  61
  62     if (frames_count && out_frames[frames_count - 1] == 0) {
  63         -- frames_count;
  64     }
  65
  66     return frames_count;
  67 }
  68
  69
  70 }}} // namespace boost::stacktrace::detail
  71
  72 #endif // BOOST_STACKTRACE_DETAIL_COLLECT_UNWIND_IPP