github.com/searKing/golang/go@v1.2.117/os/signal/cgo/include/boost/stacktrace/detail/collect_unwind.ipp (about)

     1  // Copyright Antony Polukhin, 2016-2023.
     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  // On iOS 32-bit ARM architecture _Unwind_Backtrace function doesn't exist, symbol is undefined.
    18  // Forcing libc backtrace() function usage.
    19  #include <boost/predef.h>
    20  #if defined(BOOST_OS_IOS_AVAILABLE) && defined(BOOST_ARCH_ARM_AVAILABLE) && BOOST_VERSION_NUMBER_MAJOR(BOOST_ARCH_ARM) < 8
    21  #define BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION
    22  #endif
    23  
    24  #if defined(BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION)
    25  #include <execinfo.h>
    26  #include <algorithm>
    27  #else
    28  #include <unwind.h>
    29  #endif
    30  #include <cstdio>
    31  
    32  #if !defined(_GNU_SOURCE) && !defined(BOOST_STACKTRACE_GNU_SOURCE_NOT_REQUIRED) && !defined(BOOST_WINDOWS)
    33  #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`."
    34  #endif
    35  
    36  namespace boost { namespace stacktrace { namespace detail {
    37  
    38  #if !defined(BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION)
    39  struct unwind_state {
    40      std::size_t frames_to_skip;
    41      native_frame_ptr_t* current;
    42      native_frame_ptr_t* end;
    43  };
    44  
    45  inline _Unwind_Reason_Code unwind_callback(::_Unwind_Context* context, void* arg) {
    46      // Note: do not write `::_Unwind_GetIP` because it is a macro on some platforms.
    47      // Use `_Unwind_GetIP` instead!
    48      unwind_state* const state = static_cast<unwind_state*>(arg);
    49      if (state->frames_to_skip) {
    50          --state->frames_to_skip;
    51          return _Unwind_GetIP(context) ? ::_URC_NO_REASON : ::_URC_END_OF_STACK;
    52      }
    53  
    54      *state->current =  reinterpret_cast<native_frame_ptr_t>(
    55          _Unwind_GetIP(context)
    56      );
    57  
    58      ++state->current;
    59      if (!*(state->current - 1) || state->current == state->end) {
    60          return ::_URC_END_OF_STACK;
    61      }
    62      return ::_URC_NO_REASON;
    63  }
    64  #endif //!defined(BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION)
    65  
    66  std::size_t this_thread_frames::collect(native_frame_ptr_t* out_frames, std::size_t max_frames_count, std::size_t skip) noexcept {
    67      std::size_t frames_count = 0;
    68      if (!max_frames_count) {
    69          return frames_count;
    70      }
    71      skip += 1;
    72  
    73  #if defined(BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION)
    74      // According to https://opensource.apple.com/source/Libc/Libc-1272.200.26/gen/backtrace.c.auto.html
    75      // it looks like the `::backtrace` is async signal safe.
    76      frames_count = static_cast<size_t>(::backtrace(const_cast<void **>(out_frames), static_cast<int>(max_frames_count)));
    77  
    78      // NOTE: There is no way to pass "skip" count to backtrace function so we need to perform left shift operation.
    79      // If number of elements in result backtrace is >= max_frames_count then "skip" elements are wasted.
    80      if (frames_count && skip) {
    81          if (skip >= frames_count) {
    82              frames_count = 0;
    83          } else {
    84              std::copy(out_frames + skip, out_frames + frames_count, out_frames);
    85              frames_count -= skip;
    86          }
    87      }
    88  #else
    89      boost::stacktrace::detail::unwind_state state = { skip, out_frames, out_frames + max_frames_count };
    90      ::_Unwind_Backtrace(&boost::stacktrace::detail::unwind_callback, &state);
    91      frames_count = state.current - out_frames;
    92  #endif //defined(BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION)
    93  
    94      if (frames_count && out_frames[frames_count - 1] == 0) {
    95          -- frames_count;
    96      }
    97  
    98      return frames_count;
    99  }
   100  
   101  
   102  }}} // namespace boost::stacktrace::detail
   103  
   104  #undef BOOST_STACKTRACE_USE_LIBC_BACKTRACE_FUNCTION
   105  
   106  #endif // BOOST_STACKTRACE_DETAIL_COLLECT_UNWIND_IPP