#ifdef CPPTRACE_UNWIND_WITH_LIBUNWIND

#include "unwind/unwind.hpp"

#include "utils/common.hpp"

#include "utils/error.hpp"

#include "utils/utils.hpp"

#include <algorithm>

#include <cassert>

#include <cstddef>

#include <vector>

#include <libunwind.h>

namespace cpptrace {

namespace detail {

CPPTRACE_FORCE_NO_INLINE

std::vector<frame_ptr> capture_frames(std::size_t skip, std::size_t max_depth) {

skip++;

std::vector<frame_ptr> frames;

unw_context_t context;

unw_cursor_t cursor;

unw_getcontext(&context);

unw_init_local(&cursor, &context);

do {

unw_word_t pc;

unw_word_t sp;

unw_get_reg(&cursor, UNW_REG_IP, &pc);

unw_get_reg(&cursor, UNW_REG_SP, &sp);

if(skip) {

skip--;

} else {

// pc is the instruction after the `call`, adjust back to the previous instruction

frames.push_back(to_frame_ptr(pc) - 1);

}

} while(unw_step(&cursor) > 0 && frames.size() < max_depth);

return frames;

}

CPPTRACE_FORCE_NO_INLINE

std::size_t safe_capture_frames(frame_ptr* buffer, std::size_t size, std::size_t skip, std::size_t max_depth) {

// some code duplication, but whatever

skip++;

unw_context_t context;

unw_cursor_t cursor;

// thread and signal-safe https://www.nongnu.org/libunwind/man/unw_getcontext(3).html

unw_getcontext(&context);

// thread and signal-safe https://www.nongnu.org/libunwind/man/unw_init_local(3).html

unw_init_local(&cursor, &context);

size_t i = 0;

while(i < size && i < max_depth) {

unw_word_t pc;

unw_word_t sp;

// thread and signal-safe https://www.nongnu.org/libunwind/man/unw_get_reg(3).html

unw_get_reg(&cursor, UNW_REG_IP, &pc);

unw_get_reg(&cursor, UNW_REG_SP, &sp);

if(skip) {

skip--;

} else {

// thread and signal-safe

if(unw_is_signal_frame(&cursor)) {

// pc is the instruction that caused the signal

// just a cast, thread and signal safe

buffer[i] = to_frame_ptr(pc);

} else {

// pc is the instruction after the `call`, adjust back to the previous instruction

// just a cast, thread and signal safe

buffer[i] = to_frame_ptr(pc) - 1;

}

i++;

}

// thread and signal-safe as long as the cursor is in the local address space, which it is

// https://www.nongnu.org/libunwind/man/unw_step(3).html

if(unw_step(&cursor) <= 0) {

break;

}

}

return i;

}

bool has_safe_unwind() {

return true;

}

}

}

#endif