Adding upstream version 3.8.1.upstream/3.8.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4471 insertions, 0 deletions

diff --git a/contrib/backward-cpp/backward.hpp b/contrib/backward-cpp/backward.hpp
new file mode 100644
index 0000000..ca09b72
--- /dev/null
+++ b/contrib/backward-cpp/backward.hpp
@@ -0,0 +1,4471 @@
+/*
+ * backward.hpp
+ * Copyright 2013 Google Inc. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef H_6B9572DA_A64B_49E6_B234_051480991C89
+#define H_6B9572DA_A64B_49E6_B234_051480991C89
+
+#ifndef __cplusplus
+#error "It's not going to compile without a C++ compiler..."
+#endif
+
+#if defined(BACKWARD_CXX11)
+#elif defined(BACKWARD_CXX98)
+#else
+#if __cplusplus >= 201103L || (defined(_MSC_VER) && _MSC_VER >= 1800)
+#define BACKWARD_CXX11
+#define BACKWARD_ATLEAST_CXX11
+#define BACKWARD_ATLEAST_CXX98
+#if __cplusplus >= 201703L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
+#define BACKWARD_ATLEAST_CXX17
+#endif
+#else
+#define BACKWARD_CXX98
+#define BACKWARD_ATLEAST_CXX98
+#endif
+#endif
+
+// You can define one of the following (or leave it to the auto-detection):
+//
+// #define BACKWARD_SYSTEM_LINUX
+//	- specialization for linux
+//
+// #define BACKWARD_SYSTEM_DARWIN
+//	- specialization for Mac OS X 10.5 and later.
+//
+// #define BACKWARD_SYSTEM_WINDOWS
+//  - specialization for Windows (Clang 9 and MSVC2017)
+//
+// #define BACKWARD_SYSTEM_UNKNOWN
+//	- placebo implementation, does nothing.
+//
+#if defined(BACKWARD_SYSTEM_LINUX)
+#elif defined(BACKWARD_SYSTEM_DARWIN)
+#elif defined(BACKWARD_SYSTEM_UNKNOWN)
+#elif defined(BACKWARD_SYSTEM_WINDOWS)
+#else
+#if defined(__linux) || defined(__linux__)
+#define BACKWARD_SYSTEM_LINUX
+#elif defined(__APPLE__)
+#define BACKWARD_SYSTEM_DARWIN
+#elif defined(_WIN32)
+#define BACKWARD_SYSTEM_WINDOWS
+#else
+#define BACKWARD_SYSTEM_UNKNOWN
+#endif
+#endif
+
+#define NOINLINE __attribute__((noinline))
+
+#include <algorithm>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <fstream>
+#include <iomanip>
+#include <iostream>
+#include <limits>
+#include <new>
+#include <sstream>
+#include <streambuf>
+#include <string>
+#include <vector>
+#include <exception>
+#include <iterator>
+
+#if defined(BACKWARD_SYSTEM_LINUX)
+
+// On linux, backtrace can back-trace or "walk" the stack using the following
+// libraries:
+//
+// #define BACKWARD_HAS_UNWIND 1
+//  - unwind comes from libgcc, but I saw an equivalent inside clang itself.
+//  - with unwind, the stacktrace is as accurate as it can possibly be, since
+//  this is used by the C++ runtine in gcc/clang for stack unwinding on
+//  exception.
+//  - normally libgcc is already linked to your program by default.
+//
+// #define BACKWARD_HAS_LIBUNWIND 1
+//  - libunwind provides, in some cases, a more accurate stacktrace as it knows
+//  to decode signal handler frames and lets us edit the context registers when
+//  unwinding, allowing stack traces over bad function references.
+//
+// #define BACKWARD_HAS_BACKTRACE == 1
+//  - backtrace seems to be a little bit more portable than libunwind, but on
+//  linux, it uses unwind anyway, but abstract away a tiny information that is
+//  sadly really important in order to get perfectly accurate stack traces.
+//  - backtrace is part of the (e)glib library.
+//
+// The default is:
+// #define BACKWARD_HAS_UNWIND == 1
+//
+// Note that only one of the define should be set to 1 at a time.
+//
+#if BACKWARD_HAS_UNWIND == 1
+#elif BACKWARD_HAS_LIBUNWIND == 1
+#elif BACKWARD_HAS_BACKTRACE == 1
+#else
+#undef BACKWARD_HAS_UNWIND
+#define BACKWARD_HAS_UNWIND 1
+#undef BACKWARD_HAS_LIBUNWIND
+#define BACKWARD_HAS_LIBUNWIND 0
+#undef BACKWARD_HAS_BACKTRACE
+#define BACKWARD_HAS_BACKTRACE 0
+#endif
+
+// On linux, backward can extract detailed information about a stack trace
+// using one of the following libraries:
+//
+// #define BACKWARD_HAS_DW 1
+//  - libdw gives you the most juicy details out of your stack traces:
+//    - object filename
+//    - function name
+//    - source filename
+//    - line and column numbers
+//    - source code snippet (assuming the file is accessible)
+//    - variable names (if not optimized out)
+//    - variable values (not supported by backward-cpp)
+//  - You need to link with the lib "dw":
+//    - apt-get install libdw-dev
+//    - g++/clang++ -ldw ...
+//
+// #define BACKWARD_HAS_BFD 1
+//  - With libbfd, you get a fair amount of details:
+//    - object filename
+//    - function name
+//    - source filename
+//    - line numbers
+//    - source code snippet (assuming the file is accessible)
+//  - You need to link with the lib "bfd":
+//    - apt-get install binutils-dev
+//    - g++/clang++ -lbfd ...
+//
+// #define BACKWARD_HAS_DWARF 1
+//  - libdwarf gives you the most juicy details out of your stack traces:
+//    - object filename
+//    - function name
+//    - source filename
+//    - line and column numbers
+//    - source code snippet (assuming the file is accessible)
+//    - variable names (if not optimized out)
+//    - variable values (not supported by backward-cpp)
+//  - You need to link with the lib "dwarf":
+//    - apt-get install libdwarf-dev
+//    - g++/clang++ -ldwarf ...
+//
+// #define BACKWARD_HAS_BACKTRACE_SYMBOL 1
+//  - backtrace provides minimal details for a stack trace:
+//    - object filename
+//    - function name
+//  - backtrace is part of the (e)glib library.
+//
+// The default is:
+// #define BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+//
+// Note that only one of the define should be set to 1 at a time.
+//
+#if BACKWARD_HAS_DW == 1
+#elif BACKWARD_HAS_BFD == 1
+#elif BACKWARD_HAS_DWARF == 1
+#elif BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+#else
+#undef BACKWARD_HAS_DW
+#define BACKWARD_HAS_DW 0
+#undef BACKWARD_HAS_BFD
+#define BACKWARD_HAS_BFD 0
+#undef BACKWARD_HAS_DWARF
+#define BACKWARD_HAS_DWARF 0
+#undef BACKWARD_HAS_BACKTRACE_SYMBOL
+#define BACKWARD_HAS_BACKTRACE_SYMBOL 1
+#endif
+
+#include <cxxabi.h>
+#include <fcntl.h>
+#ifdef __ANDROID__
+//		Old Android API levels define _Unwind_Ptr in both link.h and
+// unwind.h 		Rename the one in link.h as we are not going to be using
+// it
+#define _Unwind_Ptr _Unwind_Ptr_Custom
+#include <link.h>
+#undef _Unwind_Ptr
+#else
+#include <link.h>
+#endif
+#if defined(__ppc__) || defined(__powerpc) || defined(__powerpc__) ||        \
+    defined(__POWERPC__)
+// Linux kernel header required for the struct pt_regs definition
+// to access the NIP (Next Instruction Pointer) register value
+#include <asm/ptrace.h>
+#endif
+#include <signal.h>
+#include <sys/stat.h>
+#include <syscall.h>
+#include <unistd.h>
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#undef _GNU_SOURCE
+#else
+#include <dlfcn.h>
+#endif
+
+#if BACKWARD_HAS_BFD == 1
+//              NOTE: defining PACKAGE{,_VERSION} is required before including
+//                    bfd.h on some platforms, see also:
+//                    https://sourceware.org/bugzilla/show_bug.cgi?id=14243
+#ifndef PACKAGE
+#define PACKAGE
+#endif
+#ifndef PACKAGE_VERSION
+#define PACKAGE_VERSION
+#endif
+#include <bfd.h>
+#endif
+
+#if BACKWARD_HAS_DW == 1
+#include <dwarf.h>
+#include <elfutils/libdw.h>
+#include <elfutils/libdwfl.h>
+#endif
+
+#if BACKWARD_HAS_DWARF == 1
+#include <algorithm>
+#include <dwarf.h>
+#include <libdwarf.h>
+#include <libelf.h>
+#include <map>
+#endif
+
+#if (BACKWARD_HAS_BACKTRACE == 1) || (BACKWARD_HAS_BACKTRACE_SYMBOL == 1)
+// then we shall rely on backtrace
+#include <execinfo.h>
+#endif
+
+#endif // defined(BACKWARD_SYSTEM_LINUX)
+
+#if defined(BACKWARD_SYSTEM_DARWIN)
+// On Darwin, backtrace can back-trace or "walk" the stack using the following
+// libraries:
+//
+// #define BACKWARD_HAS_UNWIND 1
+//  - unwind comes from libgcc, but I saw an equivalent inside clang itself.
+//  - with unwind, the stacktrace is as accurate as it can possibly be, since
+//  this is used by the C++ runtine in gcc/clang for stack unwinding on
+//  exception.
+//  - normally libgcc is already linked to your program by default.
+//
+// #define BACKWARD_HAS_LIBUNWIND 1
+//  - libunwind comes from clang, which implements an API compatible version.
+//  - libunwind provides, in some cases, a more accurate stacktrace as it knows
+//  to decode signal handler frames and lets us edit the context registers when
+//  unwinding, allowing stack traces over bad function references.
+//
+// #define BACKWARD_HAS_BACKTRACE == 1
+//  - backtrace is available by default, though it does not produce as much
+//  information as another library might.
+//
+// The default is:
+// #define BACKWARD_HAS_UNWIND == 1
+//
+// Note that only one of the define should be set to 1 at a time.
+//
+#if BACKWARD_HAS_UNWIND == 1
+#elif BACKWARD_HAS_BACKTRACE == 1
+#elif BACKWARD_HAS_LIBUNWIND == 1
+#else
+#undef BACKWARD_HAS_UNWIND
+#define BACKWARD_HAS_UNWIND 1
+#undef BACKWARD_HAS_BACKTRACE
+#define BACKWARD_HAS_BACKTRACE 0
+#undef BACKWARD_HAS_LIBUNWIND
+#define BACKWARD_HAS_LIBUNWIND 0
+#endif
+
+// On Darwin, backward can extract detailed information about a stack trace
+// using one of the following libraries:
+//
+// #define BACKWARD_HAS_BACKTRACE_SYMBOL 1
+//  - backtrace provides minimal details for a stack trace:
+//    - object filename
+//    - function name
+//
+// The default is:
+// #define BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+//
+#if BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+#else
+#undef BACKWARD_HAS_BACKTRACE_SYMBOL
+#define BACKWARD_HAS_BACKTRACE_SYMBOL 1
+#endif
+
+#include <cxxabi.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#if (BACKWARD_HAS_BACKTRACE == 1) || (BACKWARD_HAS_BACKTRACE_SYMBOL == 1)
+#include <execinfo.h>
+#endif
+#endif // defined(BACKWARD_SYSTEM_DARWIN)
+
+#if defined(BACKWARD_SYSTEM_WINDOWS)
+
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+
+#include <basetsd.h>
+typedef SSIZE_T ssize_t;
+
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#include <windows.h>
+#include <winnt.h>
+
+#include <psapi.h>
+#include <signal.h>
+
+#ifndef __clang__
+#undef NOINLINE
+#define NOINLINE __declspec(noinline)
+#endif
+
+#ifdef _MSC_VER
+#pragma comment(lib, "psapi.lib")
+#pragma comment(lib, "dbghelp.lib")
+#endif
+
+// Comment / packing is from stackoverflow:
+// https://stackoverflow.com/questions/6205981/windows-c-stack-trace-from-a-running-app/28276227#28276227
+// Some versions of imagehlp.dll lack the proper packing directives themselves
+// so we need to do it.
+#pragma pack(push, before_imagehlp, 8)
+#include <imagehlp.h>
+#pragma pack(pop, before_imagehlp)
+
+// TODO maybe these should be undefined somewhere else?
+#undef BACKWARD_HAS_UNWIND
+#undef BACKWARD_HAS_BACKTRACE
+#if BACKWARD_HAS_PDB_SYMBOL == 1
+#else
+#undef BACKWARD_HAS_PDB_SYMBOL
+#define BACKWARD_HAS_PDB_SYMBOL 1
+#endif
+
+#endif
+
+#if BACKWARD_HAS_UNWIND == 1
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#include <unwind.h>
+#undef _GNU_SOURCE
+#else
+#include <unwind.h>
+#endif
+// while gcc's unwind.h defines something like that:
+//  extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
+//  extern _Unwind_Ptr _Unwind_GetIPInfo (struct _Unwind_Context *, int *);
+//
+// clang's unwind.h defines something like this:
+//  uintptr_t _Unwind_GetIP(struct _Unwind_Context* __context);
+//
+// Even if the _Unwind_GetIPInfo can be linked to, it is not declared, worse we
+// cannot just redeclare it because clang's unwind.h doesn't define _Unwind_Ptr
+// anyway.
+//
+// Luckily we can play on the fact that the guard macros have a different name:
+#ifdef __CLANG_UNWIND_H
+// In fact, this function still comes from libgcc (on my different linux boxes,
+// clang links against libgcc).
+#include <inttypes.h>
+extern "C" uintptr_t _Unwind_GetIPInfo(_Unwind_Context *, int *);
+#endif
+
+#endif // BACKWARD_HAS_UNWIND == 1
+
+#if BACKWARD_HAS_LIBUNWIND == 1
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#endif // BACKWARD_HAS_LIBUNWIND == 1
+
+#ifdef BACKWARD_ATLEAST_CXX11
+#include <unordered_map>
+#include <utility> // for std::swap
+namespace backward {
+namespace details {
+template <typename K, typename V> struct hashtable {
+  typedef std::unordered_map<K, V> type;
+};
+using std::move;
+} // namespace details
+} // namespace backward
+#else // NOT BACKWARD_ATLEAST_CXX11
+#define nullptr NULL
+#define override
+#include <map>
+namespace backward {
+namespace details {
+template <typename K, typename V> struct hashtable {
+  typedef std::map<K, V> type;
+};
+template <typename T> const T &move(const T &v) { return v; }
+template <typename T> T &move(T &v) { return v; }
+} // namespace details
+} // namespace backward
+#endif // BACKWARD_ATLEAST_CXX11
+
+namespace backward {
+namespace details {
+#if defined(BACKWARD_SYSTEM_WINDOWS)
+const char kBackwardPathDelimiter[] = ";";
+#else
+const char kBackwardPathDelimiter[] = ":";
+#endif
+} // namespace details
+} // namespace backward
+
+namespace backward {
+
+namespace system_tag {
+struct linux_tag; // seems that I cannot call that "linux" because the name
+// is already defined... so I am adding _tag everywhere.
+struct darwin_tag;
+struct windows_tag;
+struct unknown_tag;
+
+#if defined(BACKWARD_SYSTEM_LINUX)
+typedef linux_tag current_tag;
+#elif defined(BACKWARD_SYSTEM_DARWIN)
+typedef darwin_tag current_tag;
+#elif defined(BACKWARD_SYSTEM_WINDOWS)
+typedef windows_tag current_tag;
+#elif defined(BACKWARD_SYSTEM_UNKNOWN)
+typedef unknown_tag current_tag;
+#else
+#error "May I please get my system defines?"
+#endif
+} // namespace system_tag
+
+namespace trace_resolver_tag {
+#if defined(BACKWARD_SYSTEM_LINUX)
+struct libdw;
+struct libbfd;
+struct libdwarf;
+struct backtrace_symbol;
+
+#if BACKWARD_HAS_DW == 1
+typedef libdw current;
+#elif BACKWARD_HAS_BFD == 1
+typedef libbfd current;
+#elif BACKWARD_HAS_DWARF == 1
+typedef libdwarf current;
+#elif BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+typedef backtrace_symbol current;
+#else
+#error "You shall not pass, until you know what you want."
+#endif
+#elif defined(BACKWARD_SYSTEM_DARWIN)
+struct backtrace_symbol;
+
+#if BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+typedef backtrace_symbol current;
+#else
+#error "You shall not pass, until you know what you want."
+#endif
+#elif defined(BACKWARD_SYSTEM_WINDOWS)
+struct pdb_symbol;
+#if BACKWARD_HAS_PDB_SYMBOL == 1
+typedef pdb_symbol current;
+#else
+#error "You shall not pass, until you know what you want."
+#endif
+#endif
+} // namespace trace_resolver_tag
+
+namespace details {
+
+template <typename T> struct rm_ptr { typedef T type; };
+
+template <typename T> struct rm_ptr<T *> { typedef T type; };
+
+template <typename T> struct rm_ptr<const T *> { typedef const T type; };
+
+template <typename R, typename T, R (*F)(T)> struct deleter {
+  template <typename U> void operator()(U &ptr) const { (*F)(ptr); }
+};
+
+template <typename T> struct default_delete {
+  void operator()(T &ptr) const { delete ptr; }
+};
+
+template <typename T, typename Deleter = deleter<void, void *, &::free>>
+class handle {
+  struct dummy;
+  T _val;
+  bool _empty;
+
+#ifdef BACKWARD_ATLEAST_CXX11
+  handle(const handle &) = delete;
+  handle &operator=(const handle &) = delete;
+#endif
+
+public:
+  ~handle() {
+    if (!_empty) {
+      Deleter()(_val);
+    }
+  }
+
+  explicit handle() : _val(), _empty(true) {}
+  explicit handle(T val) : _val(val), _empty(false) {
+    if (!_val)
+      _empty = true;
+  }
+
+#ifdef BACKWARD_ATLEAST_CXX11
+  handle(handle &&from) : _empty(true) { swap(from); }
+  handle &operator=(handle &&from) {
+    swap(from);
+    return *this;
+  }
+#else
+  explicit handle(const handle &from) : _empty(true) {
+    // some sort of poor man's move semantic.
+    swap(const_cast<handle &>(from));
+  }
+  handle &operator=(const handle &from) {
+    // some sort of poor man's move semantic.
+    swap(const_cast<handle &>(from));
+    return *this;
+  }
+#endif
+
+  void reset(T new_val) {
+    handle tmp(new_val);
+    swap(tmp);
+  }
+
+  void update(T new_val) {
+    _val = new_val;
+    _empty = !static_cast<bool>(new_val);
+  }
+
+  operator const dummy *() const {
+    if (_empty) {
+      return nullptr;
+    }
+    return reinterpret_cast<const dummy *>(_val);
+  }
+  T get() { return _val; }
+  T release() {
+    _empty = true;
+    return _val;
+  }
+  void swap(handle &b) {
+    using std::swap;
+    swap(b._val, _val);     // can throw, we are safe here.
+    swap(b._empty, _empty); // should not throw: if you cannot swap two
+    // bools without throwing... It's a lost cause anyway!
+  }
+
+  T &operator->() { return _val; }
+  const T &operator->() const { return _val; }
+
+  typedef typename rm_ptr<T>::type &ref_t;
+  typedef const typename rm_ptr<T>::type &const_ref_t;
+  ref_t operator*() { return *_val; }
+  const_ref_t operator*() const { return *_val; }
+  ref_t operator[](size_t idx) { return _val[idx]; }
+
+  // Watch out, we've got a badass over here
+  T *operator&() {
+    _empty = false;
+    return &_val;
+  }
+};
+
+// Default demangler implementation (do nothing).
+template <typename TAG> struct demangler_impl {
+  static std::string demangle(const char *funcname) { return funcname; }
+};
+
+#if defined(BACKWARD_SYSTEM_LINUX) || defined(BACKWARD_SYSTEM_DARWIN)
+
+template <> struct demangler_impl<system_tag::current_tag> {
+  demangler_impl() : _demangle_buffer_length(0) {}
+
+  std::string demangle(const char *funcname) {
+    using namespace details;
+    char *result = abi::__cxa_demangle(funcname, _demangle_buffer.get(),
+                                       &_demangle_buffer_length, nullptr);
+    if (result) {
+      _demangle_buffer.update(result);
+      return result;
+    }
+    return funcname;
+  }
+
+private:
+  details::handle<char *> _demangle_buffer;
+  size_t _demangle_buffer_length;
+};
+
+#endif // BACKWARD_SYSTEM_LINUX || BACKWARD_SYSTEM_DARWIN
+
+struct demangler : public demangler_impl<system_tag::current_tag> {};
+
+// Split a string on the platform's PATH delimiter.  Example: if delimiter
+// is ":" then:
+//   ""              --> []
+//   ":"             --> ["",""]
+//   "::"            --> ["","",""]
+//   "/a/b/c"        --> ["/a/b/c"]
+//   "/a/b/c:/d/e/f" --> ["/a/b/c","/d/e/f"]
+//   etc.
+inline std::vector<std::string> split_source_prefixes(const std::string &s) {
+  std::vector<std::string> out;
+  size_t last = 0;
+  size_t next = 0;
+  size_t delimiter_size = sizeof(kBackwardPathDelimiter) - 1;
+  while ((next = s.find(kBackwardPathDelimiter, last)) != std::string::npos) {
+    out.push_back(s.substr(last, next - last));
+    last = next + delimiter_size;
+  }
+  if (last <= s.length()) {
+    out.push_back(s.substr(last));
+  }
+  return out;
+}
+
+} // namespace details
+
+/*************** A TRACE ***************/
+
+struct Trace {
+  void *addr;
+  size_t idx;
+
+  Trace() : addr(nullptr), idx(0) {}
+
+  explicit Trace(void *_addr, size_t _idx) : addr(_addr), idx(_idx) {}
+};
+
+struct ResolvedTrace : public Trace {
+
+  struct SourceLoc {
+    std::string function;
+    std::string filename;
+    unsigned line;
+    unsigned col;
+
+    SourceLoc() : line(0), col(0) {}
+
+    bool operator==(const SourceLoc &b) const {
+      return function == b.function && filename == b.filename &&
+             line == b.line && col == b.col;
+    }
+
+    bool operator!=(const SourceLoc &b) const { return !(*this == b); }
+  };
+
+  // In which binary object this trace is located.
+  std::string object_filename;
+
+  // The function in the object that contain the trace. This is not the same
+  // as source.function which can be an function inlined in object_function.
+  std::string object_function;
+
+  // The source location of this trace. It is possible for filename to be
+  // empty and for line/col to be invalid (value 0) if this information
+  // couldn't be deduced, for example if there is no debug information in the
+  // binary object.
+  SourceLoc source;
+
+  // An optionals list of "inliners". All the successive sources location
+  // from where the source location of the trace (the attribute right above)
+  // is inlined. It is especially useful when you compiled with optimization.
+  typedef std::vector<SourceLoc> source_locs_t;
+  source_locs_t inliners;
+
+  ResolvedTrace() : Trace() {}
+  ResolvedTrace(const Trace &mini_trace) : Trace(mini_trace) {}
+};
+
+/*************** STACK TRACE ***************/
+
+// default implemention.
+template <typename TAG> class StackTraceImpl {
+public:
+  size_t size() const { return 0; }
+  Trace operator[](size_t) const { return Trace(); }
+  size_t load_here(size_t = 0) { return 0; }
+  size_t load_from(void *, size_t = 0, void * = nullptr, void * = nullptr) {
+    return 0;
+  }
+  size_t thread_id() const { return 0; }
+  void skip_n_firsts(size_t) {}
+};
+
+class StackTraceImplBase {
+public:
+  StackTraceImplBase()
+      : _thread_id(0), _skip(0), _context(nullptr), _error_addr(nullptr) {}
+
+  size_t thread_id() const { return _thread_id; }
+
+  void skip_n_firsts(size_t n) { _skip = n; }
+
+protected:
+  void load_thread_info() {
+#ifdef BACKWARD_SYSTEM_LINUX
+#ifndef __ANDROID__
+    _thread_id = static_cast<size_t>(syscall(SYS_gettid));
+#else
+    _thread_id = static_cast<size_t>(gettid());
+#endif
+    if (_thread_id == static_cast<size_t>(getpid())) {
+      // If the thread is the main one, let's hide that.
+      // I like to keep little secret sometimes.
+      _thread_id = 0;
+    }
+#elif defined(BACKWARD_SYSTEM_DARWIN)
+    _thread_id = reinterpret_cast<size_t>(pthread_self());
+    if (pthread_main_np() == 1) {
+      // If the thread is the main one, let's hide that.
+      _thread_id = 0;
+    }
+#endif
+  }
+
+  void set_context(void *context) { _context = context; }
+  void *context() const { return _context; }
+
+  void set_error_addr(void *error_addr) { _error_addr = error_addr; }
+  void *error_addr() const { return _error_addr; }
+
+  size_t skip_n_firsts() const { return _skip; }
+
+private:
+  size_t _thread_id;
+  size_t _skip;
+  void *_context;
+  void *_error_addr;
+};
+
+class StackTraceImplHolder : public StackTraceImplBase {
+public:
+  size_t size() const {
+    return (_stacktrace.size() >= skip_n_firsts())
+               ? _stacktrace.size() - skip_n_firsts()
+               : 0;
+  }
+  Trace operator[](size_t idx) const {
+    if (idx >= size()) {
+      return Trace();
+    }
+    return Trace(_stacktrace[idx + skip_n_firsts()], idx);
+  }
+  void *const *begin() const {
+    if (size()) {
+      return &_stacktrace[skip_n_firsts()];
+    }
+    return nullptr;
+  }
+
+protected:
+  std::vector<void *> _stacktrace;
+};
+
+#if BACKWARD_HAS_UNWIND == 1
+
+namespace details {
+
+template <typename F> class Unwinder {
+public:
+  size_t operator()(F &f, size_t depth) {
+    _f = &f;
+    _index = -1;
+    _depth = depth;
+    _Unwind_Backtrace(&this->backtrace_trampoline, this);
+    return static_cast<size_t>(_index);
+  }
+
+private:
+  F *_f;
+  ssize_t _index;
+  size_t _depth;
+
+  static _Unwind_Reason_Code backtrace_trampoline(_Unwind_Context *ctx,
+                                                  void *self) {
+    return (static_cast<Unwinder *>(self))->backtrace(ctx);
+  }
+
+  _Unwind_Reason_Code backtrace(_Unwind_Context *ctx) {
+    if (_index >= 0 && static_cast<size_t>(_index) >= _depth)
+      return _URC_END_OF_STACK;
+
+    int ip_before_instruction = 0;
+    uintptr_t ip = _Unwind_GetIPInfo(ctx, &ip_before_instruction);
+
+    if (!ip_before_instruction) {
+      // calculating 0-1 for unsigned, looks like a possible bug to sanitiziers,
+      // so let's do it explicitly:
+      if (ip == 0) {
+        ip = std::numeric_limits<uintptr_t>::max(); // set it to 0xffff... (as
+                                                    // from casting 0-1)
+      } else {
+        ip -= 1; // else just normally decrement it (no overflow/underflow will
+                 // happen)
+      }
+    }
+
+    if (_index >= 0) { // ignore first frame.
+      (*_f)(static_cast<size_t>(_index), reinterpret_cast<void *>(ip));
+    }
+    _index += 1;
+    return _URC_NO_REASON;
+  }
+};
+
+template <typename F> size_t unwind(F f, size_t depth) {
+  Unwinder<F> unwinder;
+  return unwinder(f, depth);
+}
+
+} // namespace details
+
+template <>
+class StackTraceImpl<system_tag::current_tag> : public StackTraceImplHolder {
+public:
+  NOINLINE
+  size_t load_here(size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    load_thread_info();
+    set_context(context);
+    set_error_addr(error_addr);
+    if (depth == 0) {
+      return 0;
+    }
+    _stacktrace.resize(depth);
+    size_t trace_cnt = details::unwind(callback(*this), depth);
+    _stacktrace.resize(trace_cnt);
+    skip_n_firsts(0);
+    return size();
+  }
+  size_t load_from(void *addr, size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    load_here(depth + 8, context, error_addr);
+
+    for (size_t i = 0; i < _stacktrace.size(); ++i) {
+      if (_stacktrace[i] == addr) {
+        skip_n_firsts(i);
+        break;
+      }
+    }
+
+    _stacktrace.resize(std::min(_stacktrace.size(), skip_n_firsts() + depth));
+    return size();
+  }
+
+private:
+  struct callback {
+    StackTraceImpl &self;
+    callback(StackTraceImpl &_self) : self(_self) {}
+
+    void operator()(size_t idx, void *addr) { self._stacktrace[idx] = addr; }
+  };
+};
+
+#elif BACKWARD_HAS_LIBUNWIND == 1
+
+template <>
+class StackTraceImpl<system_tag::current_tag> : public StackTraceImplHolder {
+public:
+  __attribute__((noinline)) size_t load_here(size_t depth = 32,
+                                             void *_context = nullptr,
+                                             void *_error_addr = nullptr) {
+    set_context(_context);
+    set_error_addr(_error_addr);
+    load_thread_info();
+    if (depth == 0) {
+      return 0;
+    }
+    _stacktrace.resize(depth + 1);
+
+    int result = 0;
+
+    unw_context_t ctx;
+    size_t index = 0;
+
+    // Add the tail call. If the Instruction Pointer is the crash address it
+    // means we got a bad function pointer dereference, so we "unwind" the
+    // bad pointer manually by using the return address pointed to by the
+    // Stack Pointer as the Instruction Pointer and letting libunwind do
+    // the rest
+
+    if (context()) {
+      ucontext_t *uctx = reinterpret_cast<ucontext_t *>(context());
+#ifdef REG_RIP         // x86_64
+      if (uctx->uc_mcontext.gregs[REG_RIP] ==
+          reinterpret_cast<greg_t>(error_addr())) {
+        uctx->uc_mcontext.gregs[REG_RIP] =
+            *reinterpret_cast<size_t *>(uctx->uc_mcontext.gregs[REG_RSP]);
+      }
+      _stacktrace[index] =
+          reinterpret_cast<void *>(uctx->uc_mcontext.gregs[REG_RIP]);
+      ++index;
+      ctx = *reinterpret_cast<unw_context_t *>(uctx);
+#elif defined(REG_EIP) // x86_32
+      if (uctx->uc_mcontext.gregs[REG_EIP] ==
+          reinterpret_cast<greg_t>(error_addr())) {
+        uctx->uc_mcontext.gregs[REG_EIP] =
+            *reinterpret_cast<size_t *>(uctx->uc_mcontext.gregs[REG_ESP]);
+      }
+      _stacktrace[index] =
+          reinterpret_cast<void *>(uctx->uc_mcontext.gregs[REG_EIP]);
+      ++index;
+      ctx = *reinterpret_cast<unw_context_t *>(uctx);
+#elif defined(__arm__)
+      // libunwind uses its own context type for ARM unwinding.
+      // Copy the registers from the signal handler's context so we can
+      // unwind
+      unw_getcontext(&ctx);
+      ctx.regs[UNW_ARM_R0] = uctx->uc_mcontext.arm_r0;
+      ctx.regs[UNW_ARM_R1] = uctx->uc_mcontext.arm_r1;
+      ctx.regs[UNW_ARM_R2] = uctx->uc_mcontext.arm_r2;
+      ctx.regs[UNW_ARM_R3] = uctx->uc_mcontext.arm_r3;
+      ctx.regs[UNW_ARM_R4] = uctx->uc_mcontext.arm_r4;
+      ctx.regs[UNW_ARM_R5] = uctx->uc_mcontext.arm_r5;
+      ctx.regs[UNW_ARM_R6] = uctx->uc_mcontext.arm_r6;
+      ctx.regs[UNW_ARM_R7] = uctx->uc_mcontext.arm_r7;
+      ctx.regs[UNW_ARM_R8] = uctx->uc_mcontext.arm_r8;
+      ctx.regs[UNW_ARM_R9] = uctx->uc_mcontext.arm_r9;
+      ctx.regs[UNW_ARM_R10] = uctx->uc_mcontext.arm_r10;
+      ctx.regs[UNW_ARM_R11] = uctx->uc_mcontext.arm_fp;
+      ctx.regs[UNW_ARM_R12] = uctx->uc_mcontext.arm_ip;
+      ctx.regs[UNW_ARM_R13] = uctx->uc_mcontext.arm_sp;
+      ctx.regs[UNW_ARM_R14] = uctx->uc_mcontext.arm_lr;
+      ctx.regs[UNW_ARM_R15] = uctx->uc_mcontext.arm_pc;
+
+      // If we have crashed in the PC use the LR instead, as this was
+      // a bad function dereference
+      if (reinterpret_cast<unsigned long>(error_addr()) ==
+          uctx->uc_mcontext.arm_pc) {
+        ctx.regs[UNW_ARM_R15] =
+            uctx->uc_mcontext.arm_lr - sizeof(unsigned long);
+      }
+      _stacktrace[index] = reinterpret_cast<void *>(ctx.regs[UNW_ARM_R15]);
+      ++index;
+#elif defined(__APPLE__) && defined(__x86_64__)
+      unw_getcontext(&ctx);
+      // OS X's implementation of libunwind uses its own context object
+      // so we need to convert the passed context to libunwind's format
+      // (information about the data layout taken from unw_getcontext.s
+      // in Apple's libunwind source
+      ctx.data[0] = uctx->uc_mcontext->__ss.__rax;
+      ctx.data[1] = uctx->uc_mcontext->__ss.__rbx;
+      ctx.data[2] = uctx->uc_mcontext->__ss.__rcx;
+      ctx.data[3] = uctx->uc_mcontext->__ss.__rdx;
+      ctx.data[4] = uctx->uc_mcontext->__ss.__rdi;
+      ctx.data[5] = uctx->uc_mcontext->__ss.__rsi;
+      ctx.data[6] = uctx->uc_mcontext->__ss.__rbp;
+      ctx.data[7] = uctx->uc_mcontext->__ss.__rsp;
+      ctx.data[8] = uctx->uc_mcontext->__ss.__r8;
+      ctx.data[9] = uctx->uc_mcontext->__ss.__r9;
+      ctx.data[10] = uctx->uc_mcontext->__ss.__r10;
+      ctx.data[11] = uctx->uc_mcontext->__ss.__r11;
+      ctx.data[12] = uctx->uc_mcontext->__ss.__r12;
+      ctx.data[13] = uctx->uc_mcontext->__ss.__r13;
+      ctx.data[14] = uctx->uc_mcontext->__ss.__r14;
+      ctx.data[15] = uctx->uc_mcontext->__ss.__r15;
+      ctx.data[16] = uctx->uc_mcontext->__ss.__rip;
+
+      // If the IP is the same as the crash address we have a bad function
+      // dereference The caller's address is pointed to by %rsp, so we
+      // dereference that value and set it to be the next frame's IP.
+      if (uctx->uc_mcontext->__ss.__rip ==
+          reinterpret_cast<__uint64_t>(error_addr())) {
+        ctx.data[16] =
+            *reinterpret_cast<__uint64_t *>(uctx->uc_mcontext->__ss.__rsp);
+      }
+      _stacktrace[index] = reinterpret_cast<void *>(ctx.data[16]);
+      ++index;
+#elif defined(__APPLE__)
+      unw_getcontext(&ctx)
+          // TODO: Convert the ucontext_t to libunwind's unw_context_t like
+          // we do in 64 bits
+          if (ctx.uc_mcontext->__ss.__eip ==
+              reinterpret_cast<greg_t>(error_addr())) {
+        ctx.uc_mcontext->__ss.__eip = ctx.uc_mcontext->__ss.__esp;
+      }
+      _stacktrace[index] =
+          reinterpret_cast<void *>(ctx.uc_mcontext->__ss.__eip);
+      ++index;
+#endif
+    }
+
+    unw_cursor_t cursor;
+    if (context()) {
+#if defined(UNW_INIT_SIGNAL_FRAME)
+      result = unw_init_local2(&cursor, &ctx, UNW_INIT_SIGNAL_FRAME);
+#else
+      result = unw_init_local(&cursor, &ctx);
+#endif
+    } else {
+      unw_getcontext(&ctx);
+      ;
+      result = unw_init_local(&cursor, &ctx);
+    }
+
+    if (result != 0)
+      return 1;
+
+    unw_word_t ip = 0;
+
+    while (index <= depth && unw_step(&cursor) > 0) {
+      result = unw_get_reg(&cursor, UNW_REG_IP, &ip);
+      if (result == 0) {
+        _stacktrace[index] = reinterpret_cast<void *>(--ip);
+        ++index;
+      }
+    }
+    --index;
+
+    _stacktrace.resize(index + 1);
+    skip_n_firsts(0);
+    return size();
+  }
+
+  size_t load_from(void *addr, size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    load_here(depth + 8, context, error_addr);
+
+    for (size_t i = 0; i < _stacktrace.size(); ++i) {
+      if (_stacktrace[i] == addr) {
+        skip_n_firsts(i);
+        _stacktrace[i] = (void *)((uintptr_t)_stacktrace[i]);
+        break;
+      }
+    }
+
+    _stacktrace.resize(std::min(_stacktrace.size(), skip_n_firsts() + depth));
+    return size();
+  }
+};
+
+#elif defined(BACKWARD_HAS_BACKTRACE)
+
+template <>
+class StackTraceImpl<system_tag::current_tag> : public StackTraceImplHolder {
+public:
+  NOINLINE
+  size_t load_here(size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    set_context(context);
+    set_error_addr(error_addr);
+    load_thread_info();
+    if (depth == 0) {
+      return 0;
+    }
+    _stacktrace.resize(depth + 1);
+    size_t trace_cnt = backtrace(&_stacktrace[0], _stacktrace.size());
+    _stacktrace.resize(trace_cnt);
+    skip_n_firsts(1);
+    return size();
+  }
+
+  size_t load_from(void *addr, size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    load_here(depth + 8, context, error_addr);
+
+    for (size_t i = 0; i < _stacktrace.size(); ++i) {
+      if (_stacktrace[i] == addr) {
+        skip_n_firsts(i);
+        _stacktrace[i] = (void *)((uintptr_t)_stacktrace[i] + 1);
+        break;
+      }
+    }
+
+    _stacktrace.resize(std::min(_stacktrace.size(), skip_n_firsts() + depth));
+    return size();
+  }
+};
+
+#elif defined(BACKWARD_SYSTEM_WINDOWS)
+
+template <>
+class StackTraceImpl<system_tag::current_tag> : public StackTraceImplHolder {
+public:
+  // We have to load the machine type from the image info
+  // So we first initialize the resolver, and it tells us this info
+  void set_machine_type(DWORD machine_type) { machine_type_ = machine_type; }
+  void set_context(CONTEXT *ctx) { ctx_ = ctx; }
+  void set_thread_handle(HANDLE handle) { thd_ = handle; }
+
+  NOINLINE
+  size_t load_here(size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    set_context(static_cast<CONTEXT*>(context));
+    set_error_addr(error_addr);
+    CONTEXT localCtx; // used when no context is provided
+
+    if (depth == 0) {
+      return 0;
+    }
+
+    if (!ctx_) {
+      ctx_ = &localCtx;
+      RtlCaptureContext(ctx_);
+    }
+
+    if (!thd_) {
+      thd_ = GetCurrentThread();
+    }
+
+    HANDLE process = GetCurrentProcess();
+
+    STACKFRAME64 s;
+    memset(&s, 0, sizeof(STACKFRAME64));
+
+    // TODO: 32 bit context capture
+    s.AddrStack.Mode = AddrModeFlat;
+    s.AddrFrame.Mode = AddrModeFlat;
+    s.AddrPC.Mode = AddrModeFlat;
+#ifdef _M_X64
+    s.AddrPC.Offset = ctx_->Rip;
+    s.AddrStack.Offset = ctx_->Rsp;
+    s.AddrFrame.Offset = ctx_->Rbp;
+#else
+    s.AddrPC.Offset = ctx_->Eip;
+    s.AddrStack.Offset = ctx_->Esp;
+    s.AddrFrame.Offset = ctx_->Ebp;
+#endif
+
+    if (!machine_type_) {
+#ifdef _M_X64
+      machine_type_ = IMAGE_FILE_MACHINE_AMD64;
+#else
+      machine_type_ = IMAGE_FILE_MACHINE_I386;
+#endif
+    }
+
+    for (;;) {
+      // NOTE: this only works if PDBs are already loaded!
+      SetLastError(0);
+      if (!StackWalk64(machine_type_, process, thd_, &s, ctx_, NULL,
+                       SymFunctionTableAccess64, SymGetModuleBase64, NULL))
+        break;
+
+      if (s.AddrReturn.Offset == 0)
+        break;
+
+      _stacktrace.push_back(reinterpret_cast<void *>(s.AddrPC.Offset));
+
+      if (size() >= depth)
+        break;
+    }
+
+    return size();
+  }
+
+  size_t load_from(void *addr, size_t depth = 32, void *context = nullptr,
+                   void *error_addr = nullptr) {
+    load_here(depth + 8, context, error_addr);
+
+    for (size_t i = 0; i < _stacktrace.size(); ++i) {
+      if (_stacktrace[i] == addr) {
+        skip_n_firsts(i);
+        break;
+      }
+    }
+
+    _stacktrace.resize(std::min(_stacktrace.size(), skip_n_firsts() + depth));
+    return size();
+  }
+
+private:
+  DWORD machine_type_ = 0;
+  HANDLE thd_ = 0;
+  CONTEXT *ctx_ = nullptr;
+};
+
+#endif
+
+class StackTrace : public StackTraceImpl<system_tag::current_tag> {};
+
+/*************** TRACE RESOLVER ***************/
+
+class TraceResolverImplBase {
+public:
+  virtual ~TraceResolverImplBase() {}
+
+  virtual void load_addresses(void *const*addresses, int address_count) {
+    (void)addresses;
+    (void)address_count;
+  }
+
+  template <class ST> void load_stacktrace(ST &st) {
+    load_addresses(st.begin(), (int)st.size());
+  }
+
+  virtual ResolvedTrace resolve(ResolvedTrace t) { return t; }
+
+protected:
+  std::string demangle(const char *funcname) {
+    return _demangler.demangle(funcname);
+  }
+
+private:
+  details::demangler _demangler;
+};
+
+template <typename TAG> class TraceResolverImpl;
+
+#ifdef BACKWARD_SYSTEM_UNKNOWN
+
+template <> class TraceResolverImpl<system_tag::unknown_tag>
+    : public TraceResolverImplBase {};
+
+#endif
+
+#ifdef BACKWARD_SYSTEM_LINUX
+
+class TraceResolverLinuxBase : public TraceResolverImplBase {
+public:
+  TraceResolverLinuxBase()
+      : argv0_(get_argv0()), exec_path_(read_symlink("/proc/self/exe")) {}
+  std::string resolve_exec_path(Dl_info &symbol_info) const {
+    // mutates symbol_info.dli_fname to be filename to open and returns filename
+    // to display
+    if (symbol_info.dli_fname == argv0_) {
+      // dladdr returns argv[0] in dli_fname for symbols contained in
+      // the main executable, which is not a valid path if the
+      // executable was found by a search of the PATH environment
+      // variable; In that case, we actually open /proc/self/exe, which
+      // is always the actual executable (even if it was deleted/replaced!)
+      // but display the path that /proc/self/exe links to.
+      // However, this right away reduces probability of successful symbol
+      // resolution, because libbfd may try to find *.debug files in the
+      // same dir, in case symbols are stripped. As a result, it may try
+      // to find a file /proc/self/<exe_name>.debug, which obviously does
+      // not exist. /proc/self/exe is a last resort. First load attempt
+      // should go for the original executable file path.
+      symbol_info.dli_fname = "/proc/self/exe";
+      return exec_path_;
+    } else {
+      return symbol_info.dli_fname;
+    }
+  }
+
+private:
+  std::string argv0_;
+  std::string exec_path_;
+
+  static std::string get_argv0() {
+    std::string argv0;
+    std::ifstream ifs("/proc/self/cmdline");
+    std::getline(ifs, argv0, '\0');
+    return argv0;
+  }
+
+  static std::string read_symlink(std::string const &symlink_path) {
+    std::string path;
+    path.resize(100);
+
+    while (true) {
+      ssize_t len =
+          ::readlink(symlink_path.c_str(), &*path.begin(), path.size());
+      if (len < 0) {
+        return "";
+      }
+      if (static_cast<size_t>(len) == path.size()) {
+        path.resize(path.size() * 2);
+      } else {
+        path.resize(static_cast<std::string::size_type>(len));
+        break;
+      }
+    }
+
+    return path;
+  }
+};
+
+template <typename STACKTRACE_TAG> class TraceResolverLinuxImpl;
+
+#if BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+
+template <>
+class TraceResolverLinuxImpl<trace_resolver_tag::backtrace_symbol>
+    : public TraceResolverLinuxBase {
+public:
+  void load_addresses(void *const*addresses, int address_count) override {
+    if (address_count == 0) {
+      return;
+    }
+    _symbols.reset(backtrace_symbols(addresses, address_count));
+  }
+
+  ResolvedTrace resolve(ResolvedTrace trace) override {
+    char *filename = _symbols[trace.idx];
+    char *funcname = filename;
+    while (*funcname && *funcname != '(') {
+      funcname += 1;
+    }
+    trace.object_filename.assign(filename,
+                                 funcname); // ok even if funcname is the ending
+                                            // \0 (then we assign entire string)
+
+    if (*funcname) { // if it's not end of string (e.g. from last frame ip==0)
+      funcname += 1;
+      char *funcname_end = funcname;
+      while (*funcname_end && *funcname_end != ')' && *funcname_end != '+') {
+        funcname_end += 1;
+      }
+      *funcname_end = '\0';
+      trace.object_function = this->demangle(funcname);
+      trace.source.function = trace.object_function; // we cannot do better.
+    }
+    return trace;
+  }
+
+private:
+  details::handle<char **> _symbols;
+};
+
+#endif // BACKWARD_HAS_BACKTRACE_SYMBOL == 1
+
+#if BACKWARD_HAS_BFD == 1
+
+template <>
+class TraceResolverLinuxImpl<trace_resolver_tag::libbfd>
+    : public TraceResolverLinuxBase {
+public:
+  TraceResolverLinuxImpl() : _bfd_loaded(false) {}
+
+  ResolvedTrace resolve(ResolvedTrace trace) override {
+    Dl_info symbol_info;
+
+    // trace.addr is a virtual address in memory pointing to some code.
+    // Let's try to find from which loaded object it comes from.
+    // The loaded object can be yourself btw.
+    if (!dladdr(trace.addr, &symbol_info)) {
+      return trace; // dat broken trace...
+    }
+
+    // Now we get in symbol_info:
+    // .dli_fname:
+    //		pathname of the shared object that contains the address.
+    // .dli_fbase:
+    //		where the object is loaded in memory.
+    // .dli_sname:
+    //		the name of the nearest symbol to trace.addr, we expect a
+    //		function name.
+    // .dli_saddr:
+    //		the exact address corresponding to .dli_sname.
+
+    if (symbol_info.dli_sname) {
+      trace.object_function = demangle(symbol_info.dli_sname);
+    }
+
+    if (!symbol_info.dli_fname) {
+      return trace;
+    }
+
+    trace.object_filename = resolve_exec_path(symbol_info);
+    bfd_fileobject *fobj;
+    // Before rushing to resolution need to ensure the executable
+    // file still can be used. For that compare inode numbers of
+    // what is stored by the executable's file path, and in the
+    // dli_fname, which not necessarily equals to the executable.
+    // It can be a shared library, or /proc/self/exe, and in the
+    // latter case has drawbacks. See the exec path resolution for
+    // details. In short - the dli object should be used only as
+    // the last resort.
+    // If inode numbers are equal, it is known dli_fname and the
+    // executable file are the same. This is guaranteed by Linux,
+    // because if the executable file is changed/deleted, it will
+    // be done in a new inode. The old file will be preserved in
+    // /proc/self/exe, and may even have inode 0. The latter can
+    // happen if the inode was actually reused, and the file was
+    // kept only in the main memory.
+    //
+    struct stat obj_stat;
+    struct stat dli_stat;
+    if (stat(trace.object_filename.c_str(), &obj_stat) == 0 &&
+        stat(symbol_info.dli_fname, &dli_stat) == 0 &&
+        obj_stat.st_ino == dli_stat.st_ino) {
+      // The executable file, and the shared object containing the
+      // address are the same file. Safe to use the original path.
+      // this is preferable. Libbfd will search for stripped debug
+      // symbols in the same directory.
+      fobj = load_object_with_bfd(trace.object_filename);
+    } else{
+      // The original object file was *deleted*! The only hope is
+      // that the debug symbols are either inside the shared
+      // object file, or are in the same directory, and this is
+      // not /proc/self/exe.
+      fobj = nullptr;
+    }
+    if (fobj == nullptr || !fobj->handle) {
+      fobj = load_object_with_bfd(symbol_info.dli_fname);
+      if (!fobj->handle) {
+        return trace;
+      }
+    }
+
+    find_sym_result *details_selected; // to be filled.
+
+    // trace.addr is the next instruction to be executed after returning
+    // from the nested stack frame. In C++ this usually relate to the next
+    // statement right after the function call that leaded to a new stack
+    // frame. This is not usually what you want to see when printing out a
+    // stacktrace...
+    find_sym_result details_call_site =
+        find_symbol_details(fobj, trace.addr, symbol_info.dli_fbase);
+    details_selected = &details_call_site;
+
+#if BACKWARD_HAS_UNWIND == 0
+    // ...this is why we also try to resolve the symbol that is right
+    // before the return address. If we are lucky enough, we will get the
+    // line of the function that was called. But if the code is optimized,
+    // we might get something absolutely not related since the compiler
+    // can reschedule the return address with inline functions and
+    // tail-call optimisation (among other things that I don't even know
+    // or cannot even dream about with my tiny limited brain).
+    find_sym_result details_adjusted_call_site = find_symbol_details(
+        fobj, (void *)(uintptr_t(trace.addr) - 1), symbol_info.dli_fbase);
+
+    // In debug mode, we should always get the right thing(TM).
+    if (details_call_site.found && details_adjusted_call_site.found) {
+      // Ok, we assume that details_adjusted_call_site is a better estimation.
+      details_selected = &details_adjusted_call_site;
+      trace.addr = (void *)(uintptr_t(trace.addr) - 1);
+    }
+
+    if (details_selected == &details_call_site && details_call_site.found) {
+      // we have to re-resolve the symbol in order to reset some
+      // internal state in BFD... so we can call backtrace_inliners
+      // thereafter...
+      details_call_site =
+          find_symbol_details(fobj, trace.addr, symbol_info.dli_fbase);
+    }
+#endif // BACKWARD_HAS_UNWIND
+
+    if (details_selected->found) {
+      if (details_selected->filename) {
+        trace.source.filename = details_selected->filename;
+      }
+      trace.source.line = details_selected->line;
+
+      if (details_selected->funcname) {
+        // this time we get the name of the function where the code is
+        // located, instead of the function were the address is
+        // located. In short, if the code was inlined, we get the
+        // function correspoding to the code. Else we already got in
+        // trace.function.
+        trace.source.function = demangle(details_selected->funcname);
+
+        if (!symbol_info.dli_sname) {
+          // for the case dladdr failed to find the symbol name of
+          // the function, we might as well try to put something
+          // here.
+          trace.object_function = trace.source.function;
+        }
+      }
+
+      // Maybe the source of the trace got inlined inside the function
+      // (trace.source.function). Let's see if we can get all the inlined
+      // calls along the way up to the initial call site.
+      trace.inliners = backtrace_inliners(fobj, *details_selected);
+
+#if 0
+			if (trace.inliners.size() == 0) {
+				// Maybe the trace was not inlined... or maybe it was and we
+				// are lacking the debug information. Let's try to make the
+				// world better and see if we can get the line number of the
+				// function (trace.source.function) now.
+				//
+				// We will get the location of where the function start (to be
+				// exact: the first instruction that really start the
+				// function), not where the name of the function is defined.
+				// This can be quite far away from the name of the function
+				// btw.
+				//
+				// If the source of the function is the same as the source of
+				// the trace, we cannot say if the trace was really inlined or
+				// not.  However, if the filename of the source is different
+				// between the function and the trace... we can declare it as
+				// an inliner.  This is not 100% accurate, but better than
+				// nothing.
+
+				if (symbol_info.dli_saddr) {
+					find_sym_result details = find_symbol_details(fobj,
+							symbol_info.dli_saddr,
+							symbol_info.dli_fbase);
+
+					if (details.found) {
+						ResolvedTrace::SourceLoc diy_inliner;
+						diy_inliner.line = details.line;
+						if (details.filename) {
+							diy_inliner.filename = details.filename;
+						}
+						if (details.funcname) {
+							diy_inliner.function = demangle(details.funcname);
+						} else {
+							diy_inliner.function = trace.source.function;
+						}
+						if (diy_inliner != trace.source) {
+							trace.inliners.push_back(diy_inliner);
+						}
+					}
+				}
+			}
+#endif
+    }
+
+    return trace;
+  }
+
+private:
+  bool _bfd_loaded;
+
+  typedef details::handle<bfd *,
+                          details::deleter<bfd_boolean, bfd *, &bfd_close>>
+      bfd_handle_t;
+
+  typedef details::handle<asymbol **> bfd_symtab_t;
+
+  struct bfd_fileobject {
+    bfd_handle_t handle;
+    bfd_vma base_addr;
+    bfd_symtab_t symtab;
+    bfd_symtab_t dynamic_symtab;
+  };
+
+  typedef details::hashtable<std::string, bfd_fileobject>::type fobj_bfd_map_t;
+  fobj_bfd_map_t _fobj_bfd_map;
+
+  bfd_fileobject *load_object_with_bfd(const std::string &filename_object) {
+    using namespace details;
+
+    if (!_bfd_loaded) {
+      using namespace details;
+      bfd_init();
+      _bfd_loaded = true;
+    }
+
+    fobj_bfd_map_t::iterator it = _fobj_bfd_map.find(filename_object);
+    if (it != _fobj_bfd_map.end()) {
+      return &it->second;
+    }
+
+    // this new object is empty for now.
+    bfd_fileobject *r = &_fobj_bfd_map[filename_object];
+
+    // we do the work temporary in this one;
+    bfd_handle_t bfd_handle;
+
+    int fd = open(filename_object.c_str(), O_RDONLY);
+    bfd_handle.reset(bfd_fdopenr(filename_object.c_str(), "default", fd));
+    if (!bfd_handle) {
+      close(fd);
+      return r;
+    }
+
+    if (!bfd_check_format(bfd_handle.get(), bfd_object)) {
+      return r; // not an object? You lose.
+    }
+
+    if ((bfd_get_file_flags(bfd_handle.get()) & HAS_SYMS) == 0) {
+      return r; // that's what happen when you forget to compile in debug.
+    }
+
+    ssize_t symtab_storage_size = bfd_get_symtab_upper_bound(bfd_handle.get());
+
+    ssize_t dyn_symtab_storage_size =
+        bfd_get_dynamic_symtab_upper_bound(bfd_handle.get());
+
+    if (symtab_storage_size <= 0 && dyn_symtab_storage_size <= 0) {
+      return r; // weird, is the file is corrupted?
+    }
+
+    bfd_symtab_t symtab, dynamic_symtab;
+    ssize_t symcount = 0, dyn_symcount = 0;
+
+    if (symtab_storage_size > 0) {
+      symtab.reset(static_cast<bfd_symbol **>(
+          malloc(static_cast<size_t>(symtab_storage_size))));
+      symcount = bfd_canonicalize_symtab(bfd_handle.get(), symtab.get());
+    }
+
+    if (dyn_symtab_storage_size > 0) {
+      dynamic_symtab.reset(static_cast<bfd_symbol **>(
+          malloc(static_cast<size_t>(dyn_symtab_storage_size))));
+      dyn_symcount = bfd_canonicalize_dynamic_symtab(bfd_handle.get(),
+                                                     dynamic_symtab.get());
+    }
+
+    if (symcount <= 0 && dyn_symcount <= 0) {
+      return r; // damned, that's a stripped file that you got there!
+    }
+
+    r->handle = move(bfd_handle);
+    r->symtab = move(symtab);
+    r->dynamic_symtab = move(dynamic_symtab);
+    return r;
+  }
+
+  struct find_sym_result {
+    bool found;
+    const char *filename;
+    const char *funcname;
+    unsigned int line;
+  };
+
+  struct find_sym_context {
+    TraceResolverLinuxImpl *self;
+    bfd_fileobject *fobj;
+    void *addr;
+    void *base_addr;
+    find_sym_result result;
+  };
+
+  find_sym_result find_symbol_details(bfd_fileobject *fobj, void *addr,
+                                      void *base_addr) {
+    find_sym_context context;
+    context.self = this;
+    context.fobj = fobj;
+    context.addr = addr;
+    context.base_addr = base_addr;
+    context.result.found = false;
+    bfd_map_over_sections(fobj->handle.get(), &find_in_section_trampoline,
+                          static_cast<void *>(&context));
+    return context.result;
+  }
+
+  static void find_in_section_trampoline(bfd *, asection *section, void *data) {
+    find_sym_context *context = static_cast<find_sym_context *>(data);
+    context->self->find_in_section(
+        reinterpret_cast<bfd_vma>(context->addr),
+        reinterpret_cast<bfd_vma>(context->base_addr), context->fobj, section,
+        context->result);
+  }
+
+  void find_in_section(bfd_vma addr, bfd_vma base_addr, bfd_fileobject *fobj,
+                       asection *section, find_sym_result &result) {
+    if (result.found)
+      return;
+
+#ifdef bfd_get_section_flags
+    if ((bfd_get_section_flags(fobj->handle.get(), section) & SEC_ALLOC) == 0)
+#else
+    if ((bfd_section_flags(section) & SEC_ALLOC) == 0)
+#endif
+      return; // a debug section is never loaded automatically.
+
+#ifdef bfd_get_section_vma
+    bfd_vma sec_addr = bfd_get_section_vma(fobj->handle.get(), section);
+#else
+    bfd_vma sec_addr = bfd_section_vma(section);
+#endif
+#ifdef bfd_get_section_size
+    bfd_size_type size = bfd_get_section_size(section);
+#else
+    bfd_size_type size = bfd_section_size(section);
+#endif
+
+    // are we in the boundaries of the section?
+    if (addr < sec_addr || addr >= sec_addr + size) {
+      addr -= base_addr; // oups, a relocated object, lets try again...
+      if (addr < sec_addr || addr >= sec_addr + size) {
+        return;
+      }
+    }
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
+#endif
+    if (!result.found && fobj->symtab) {
+      result.found = bfd_find_nearest_line(
+          fobj->handle.get(), section, fobj->symtab.get(), addr - sec_addr,
+          &result.filename, &result.funcname, &result.line);
+    }
+
+    if (!result.found && fobj->dynamic_symtab) {
+      result.found = bfd_find_nearest_line(
+          fobj->handle.get(), section, fobj->dynamic_symtab.get(),
+          addr - sec_addr, &result.filename, &result.funcname, &result.line);
+    }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+  }
+
+  ResolvedTrace::source_locs_t
+  backtrace_inliners(bfd_fileobject *fobj, find_sym_result previous_result) {
+    // This function can be called ONLY after a SUCCESSFUL call to
+    // find_symbol_details. The state is global to the bfd_handle.
+    ResolvedTrace::source_locs_t results;
+    while (previous_result.found) {
+      find_sym_result result;
+      result.found = bfd_find_inliner_info(fobj->handle.get(), &result.filename,
+                                           &result.funcname, &result.line);
+
+      if (result
+              .found) /* and not (
+                            cstrings_eq(previous_result.filename,
+                         result.filename) and
+                         cstrings_eq(previous_result.funcname, result.funcname)
+                            and result.line == previous_result.line
+                            )) */
+      {
+        ResolvedTrace::SourceLoc src_loc;
+        src_loc.line = result.line;
+        if (result.filename) {
+          src_loc.filename = result.filename;
+        }
+        if (result.funcname) {
+          src_loc.function = demangle(result.funcname);
+        }
+        results.push_back(src_loc);
+      }
+      previous_result = result;
+    }
+    return results;
+  }
+
+  bool cstrings_eq(const char *a, const char *b) {
+    if (!a || !b) {
+      return false;
+    }
+    return strcmp(a, b) == 0;
+  }
+};
+#endif // BACKWARD_HAS_BFD == 1
+
+#if BACKWARD_HAS_DW == 1
+
+template <>
+class TraceResolverLinuxImpl<trace_resolver_tag::libdw>
+    : public TraceResolverLinuxBase {
+public:
+  TraceResolverLinuxImpl() : _dwfl_handle_initialized(false) {}
+
+  ResolvedTrace resolve(ResolvedTrace trace) override {
+    using namespace details;
+
+    Dwarf_Addr trace_addr = (Dwarf_Addr)trace.addr;
+
+    if (!_dwfl_handle_initialized) {
+      // initialize dwfl...
+      _dwfl_cb.reset(new Dwfl_Callbacks);
+      _dwfl_cb->find_elf = &dwfl_linux_proc_find_elf;
+      _dwfl_cb->find_debuginfo = &dwfl_standard_find_debuginfo;
+      _dwfl_cb->debuginfo_path = 0;
+
+      _dwfl_handle.reset(dwfl_begin(_dwfl_cb.get()));
+      _dwfl_handle_initialized = true;
+
+      if (!_dwfl_handle) {
+        return trace;
+      }
+
+      // ...from the current process.
+      dwfl_report_begin(_dwfl_handle.get());
+      int r = dwfl_linux_proc_report(_dwfl_handle.get(), getpid());
+      dwfl_report_end(_dwfl_handle.get(), NULL, NULL);
+      if (r < 0) {
+        return trace;
+      }
+    }
+
+    if (!_dwfl_handle) {
+      return trace;
+    }
+
+    // find the module (binary object) that contains the trace's address.
+    // This is not using any debug information, but the addresses ranges of
+    // all the currently loaded binary object.
+    Dwfl_Module *mod = dwfl_addrmodule(_dwfl_handle.get(), trace_addr);
+    if (mod) {
+      // now that we found it, lets get the name of it, this will be the
+      // full path to the running binary or one of the loaded library.
+      const char *module_name = dwfl_module_info(mod, 0, 0, 0, 0, 0, 0, 0);
+      if (module_name) {
+        trace.object_filename = module_name;
+      }
+      // We also look after the name of the symbol, equal or before this
+      // address. This is found by walking the symtab. We should get the
+      // symbol corresponding to the function (mangled) containing the
+      // address. If the code corresponding to the address was inlined,
+      // this is the name of the out-most inliner function.
+      const char *sym_name = dwfl_module_addrname(mod, trace_addr);
+      if (sym_name) {
+        trace.object_function = demangle(sym_name);
+      }
+    }
+
+    // now let's get serious, and find out the source location (file and
+    // line number) of the address.
+
+    // This function will look in .debug_aranges for the address and map it
+    // to the location of the compilation unit DIE in .debug_info and
+    // return it.
+    Dwarf_Addr mod_bias = 0;
+    Dwarf_Die *cudie = dwfl_module_addrdie(mod, trace_addr, &mod_bias);
+
+#if 1
+    if (!cudie) {
+      // Sadly clang does not generate the section .debug_aranges, thus
+      // dwfl_module_addrdie will fail early. Clang doesn't either set
+      // the lowpc/highpc/range info for every compilation unit.
+      //
+      // So in order to save the world:
+      // for every compilation unit, we will iterate over every single
+      // DIEs. Normally functions should have a lowpc/highpc/range, which
+      // we will use to infer the compilation unit.
+
+      // note that this is probably badly inefficient.
+      while ((cudie = dwfl_module_nextcu(mod, cudie, &mod_bias))) {
+        Dwarf_Die die_mem;
+        Dwarf_Die *fundie =
+            find_fundie_by_pc(cudie, trace_addr - mod_bias, &die_mem);
+        if (fundie) {
+          break;
+        }
+      }
+    }
+#endif
+
+//#define BACKWARD_I_DO_NOT_RECOMMEND_TO_ENABLE_THIS_HORRIBLE_PIECE_OF_CODE
+#ifdef BACKWARD_I_DO_NOT_RECOMMEND_TO_ENABLE_THIS_HORRIBLE_PIECE_OF_CODE
+    if (!cudie) {
+      // If it's still not enough, lets dive deeper in the shit, and try
+      // to save the world again: for every compilation unit, we will
+      // load the corresponding .debug_line section, and see if we can
+      // find our address in it.
+
+      Dwarf_Addr cfi_bias;
+      Dwarf_CFI *cfi_cache = dwfl_module_eh_cfi(mod, &cfi_bias);
+
+      Dwarf_Addr bias;
+      while ((cudie = dwfl_module_nextcu(mod, cudie, &bias))) {
+        if (dwarf_getsrc_die(cudie, trace_addr - bias)) {
+
+          // ...but if we get a match, it might be a false positive
+          // because our (address - bias) might as well be valid in a
+          // different compilation unit. So we throw our last card on
+          // the table and lookup for the address into the .eh_frame
+          // section.
+
+          handle<Dwarf_Frame *> frame;
+          dwarf_cfi_addrframe(cfi_cache, trace_addr - cfi_bias, &frame);
+          if (frame) {
+            break;
+          }
+        }
+      }
+    }
+#endif
+
+    if (!cudie) {
+      return trace; // this time we lost the game :/
+    }
+
+    // Now that we have a compilation unit DIE, this function will be able
+    // to load the corresponding section in .debug_line (if not already
+    // loaded) and hopefully find the source location mapped to our
+    // address.
+    Dwarf_Line *srcloc = dwarf_getsrc_die(cudie, trace_addr - mod_bias);
+
+    if (srcloc) {
+      const char *srcfile = dwarf_linesrc(srcloc, 0, 0);
+      if (srcfile) {
+        trace.source.filename = srcfile;
+      }
+      int line = 0, col = 0;
+      dwarf_lineno(srcloc, &line);
+      dwarf_linecol(srcloc, &col);
+      trace.source.line = line;
+      trace.source.col = col;
+    }
+
+    deep_first_search_by_pc(cudie, trace_addr - mod_bias,
+                            inliners_search_cb(trace));
+    if (trace.source.function.size() == 0) {
+      // fallback.
+      trace.source.function = trace.object_function;
+    }
+
+    return trace;
+  }
+
+private:
+  typedef details::handle<Dwfl *, details::deleter<void, Dwfl *, &dwfl_end>>
+      dwfl_handle_t;
+  details::handle<Dwfl_Callbacks *, details::default_delete<Dwfl_Callbacks *>>
+      _dwfl_cb;
+  dwfl_handle_t _dwfl_handle;
+  bool _dwfl_handle_initialized;
+
+  // defined here because in C++98, template function cannot take locally
+  // defined types... grrr.
+  struct inliners_search_cb {
+    void operator()(Dwarf_Die *die) {
+      switch (dwarf_tag(die)) {
+        const char *name;
+      case DW_TAG_subprogram:
+        if ((name = dwarf_diename(die))) {
+          trace.source.function = name;
+        }
+        break;
+
+      case DW_TAG_inlined_subroutine:
+        ResolvedTrace::SourceLoc sloc;
+        Dwarf_Attribute attr_mem;
+
+        if ((name = dwarf_diename(die))) {
+          sloc.function = name;
+        }
+        if ((name = die_call_file(die))) {
+          sloc.filename = name;
+        }
+
+        Dwarf_Word line = 0, col = 0;
+        dwarf_formudata(dwarf_attr(die, DW_AT_call_line, &attr_mem), &line);
+        dwarf_formudata(dwarf_attr(die, DW_AT_call_column, &attr_mem), &col);
+        sloc.line = (unsigned)line;
+        sloc.col = (unsigned)col;
+
+        trace.inliners.push_back(sloc);
+        break;
+      };
+    }
+    ResolvedTrace &trace;
+    inliners_search_cb(ResolvedTrace &t) : trace(t) {}
+  };
+
+  static bool die_has_pc(Dwarf_Die *die, Dwarf_Addr pc) {
+    Dwarf_Addr low, high;
+
+    // continuous range
+    if (dwarf_hasattr(die, DW_AT_low_pc) && dwarf_hasattr(die, DW_AT_high_pc)) {
+      if (dwarf_lowpc(die, &low) != 0) {
+        return false;
+      }
+      if (dwarf_highpc(die, &high) != 0) {
+        Dwarf_Attribute attr_mem;
+        Dwarf_Attribute *attr = dwarf_attr(die, DW_AT_high_pc, &attr_mem);
+        Dwarf_Word value;
+        if (dwarf_formudata(attr, &value) != 0) {
+          return false;
+        }
+        high = low + value;
+      }
+      return pc >= low && pc < high;
+    }
+
+    // non-continuous range.
+    Dwarf_Addr base;
+    ptrdiff_t offset = 0;
+    while ((offset = dwarf_ranges(die, offset, &base, &low, &high)) > 0) {
+      if (pc >= low && pc < high) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  static Dwarf_Die *find_fundie_by_pc(Dwarf_Die *parent_die, Dwarf_Addr pc,
+                                      Dwarf_Die *result) {
+    if (dwarf_child(parent_die, result) != 0) {
+      return 0;
+    }
+
+    Dwarf_Die *die = result;
+    do {
+      switch (dwarf_tag(die)) {
+      case DW_TAG_subprogram:
+      case DW_TAG_inlined_subroutine:
+        if (die_has_pc(die, pc)) {
+          return result;
+        }
+      };
+      bool declaration = false;
+      Dwarf_Attribute attr_mem;
+      dwarf_formflag(dwarf_attr(die, DW_AT_declaration, &attr_mem),
+                     &declaration);
+      if (!declaration) {
+        // let's be curious and look deeper in the tree,
+        // function are not necessarily at the first level, but
+        // might be nested inside a namespace, structure etc.
+        Dwarf_Die die_mem;
+        Dwarf_Die *indie = find_fundie_by_pc(die, pc, &die_mem);
+        if (indie) {
+          *result = die_mem;
+          return result;
+        }
+      }
+    } while (dwarf_siblingof(die, result) == 0);
+    return 0;
+  }
+
+  template <typename CB>
+  static bool deep_first_search_by_pc(Dwarf_Die *parent_die, Dwarf_Addr pc,
+                                      CB cb) {
+    Dwarf_Die die_mem;
+    if (dwarf_child(parent_die, &die_mem) != 0) {
+      return false;
+    }
+
+    bool branch_has_pc = false;
+    Dwarf_Die *die = &die_mem;
+    do {
+      bool declaration = false;
+      Dwarf_Attribute attr_mem;
+      dwarf_formflag(dwarf_attr(die, DW_AT_declaration, &attr_mem),
+                     &declaration);
+      if (!declaration) {
+        // let's be curious and look deeper in the tree, function are
+        // not necessarily at the first level, but might be nested
+        // inside a namespace, structure, a function, an inlined
+        // function etc.
+        branch_has_pc = deep_first_search_by_pc(die, pc, cb);
+      }
+      if (!branch_has_pc) {
+        branch_has_pc = die_has_pc(die, pc);
+      }
+      if (branch_has_pc) {
+        cb(die);
+      }
+    } while (dwarf_siblingof(die, &die_mem) == 0);
+    return branch_has_pc;
+  }
+
+  static const char *die_call_file(Dwarf_Die *die) {
+    Dwarf_Attribute attr_mem;
+    Dwarf_Word file_idx = 0;
+
+    dwarf_formudata(dwarf_attr(die, DW_AT_call_file, &attr_mem), &file_idx);
+
+    if (file_idx == 0) {
+      return 0;
+    }
+
+    Dwarf_Die die_mem;
+    Dwarf_Die *cudie = dwarf_diecu(die, &die_mem, 0, 0);
+    if (!cudie) {
+      return 0;
+    }
+
+    Dwarf_Files *files = 0;
+    size_t nfiles;
+    dwarf_getsrcfiles(cudie, &files, &nfiles);
+    if (!files) {
+      return 0;
+    }
+
+    return dwarf_filesrc(files, file_idx, 0, 0);
+  }
+};
+#endif // BACKWARD_HAS_DW == 1
+
+#if BACKWARD_HAS_DWARF == 1
+
+template <>
+class TraceResolverLinuxImpl<trace_resolver_tag::libdwarf>
+    : public TraceResolverLinuxBase {
+public:
+  TraceResolverLinuxImpl() : _dwarf_loaded(false) {}
+
+  ResolvedTrace resolve(ResolvedTrace trace) override {
+    // trace.addr is a virtual address in memory pointing to some code.
+    // Let's try to find from which loaded object it comes from.
+    // The loaded object can be yourself btw.
+
+    Dl_info symbol_info;
+    int dladdr_result = 0;
+#if defined(__GLIBC__)
+    link_map *link_map;
+    // We request the link map so we can get information about offsets
+    dladdr_result =
+        dladdr1(trace.addr, &symbol_info, reinterpret_cast<void **>(&link_map),
+                RTLD_DL_LINKMAP);
+#else
+    // Android doesn't have dladdr1. Don't use the linker map.
+    dladdr_result = dladdr(trace.addr, &symbol_info);
+#endif
+    if (!dladdr_result) {
+      return trace; // dat broken trace...
+    }
+
+    // Now we get in symbol_info:
+    // .dli_fname:
+    //      pathname of the shared object that contains the address.
+    // .dli_fbase:
+    //      where the object is loaded in memory.
+    // .dli_sname:
+    //      the name of the nearest symbol to trace.addr, we expect a
+    //      function name.
+    // .dli_saddr:
+    //      the exact address corresponding to .dli_sname.
+    //
+    // And in link_map:
+    // .l_addr:
+    //      difference between the address in the ELF file and the address
+    //      in memory
+    // l_name:
+    //      absolute pathname where the object was found
+
+    if (symbol_info.dli_sname) {
+      trace.object_function = demangle(symbol_info.dli_sname);
+    }
+
+    if (!symbol_info.dli_fname) {
+      return trace;
+    }
+
+    trace.object_filename = resolve_exec_path(symbol_info);
+    dwarf_fileobject &fobj = load_object_with_dwarf(symbol_info.dli_fname);
+    if (!fobj.dwarf_handle) {
+      return trace; // sad, we couldn't load the object :(
+    }
+
+#if defined(__GLIBC__)
+    // Convert the address to a module relative one by looking at
+    // the module's loading address in the link map
+    Dwarf_Addr address = reinterpret_cast<uintptr_t>(trace.addr) -
+                         reinterpret_cast<uintptr_t>(link_map->l_addr);
+#else
+    Dwarf_Addr address = reinterpret_cast<uintptr_t>(trace.addr);
+#endif
+
+    if (trace.object_function.empty()) {
+      symbol_cache_t::iterator it = fobj.symbol_cache.lower_bound(address);
+
+      if (it != fobj.symbol_cache.end()) {
+        if (it->first != address) {
+          if (it != fobj.symbol_cache.begin()) {
+            --it;
+          }
+        }
+        trace.object_function = demangle(it->second.c_str());
+      }
+    }
+
+    // Get the Compilation Unit DIE for the address
+    Dwarf_Die die = find_die(fobj, address);
+
+    if (!die) {
+      return trace; // this time we lost the game :/
+    }
+
+    // libdwarf doesn't give us direct access to its objects, it always
+    // allocates a copy for the caller. We keep that copy alive in a cache
+    // and we deallocate it later when it's no longer required.
+    die_cache_entry &die_object = get_die_cache(fobj, die);
+    if (die_object.isEmpty())
+      return trace; // We have no line section for this DIE
+
+    die_linemap_t::iterator it = die_object.line_section.lower_bound(address);
+
+    if (it != die_object.line_section.end()) {
+      if (it->first != address) {
+        if (it == die_object.line_section.begin()) {
+          // If we are on the first item of the line section
+          // but the address does not match it means that
+          // the address is below the range of the DIE. Give up.
+          return trace;
+        } else {
+          --it;
+        }
+      }
+    } else {
+      return trace; // We didn't find the address.
+    }
+
+    // Get the Dwarf_Line that the address points to and call libdwarf
+    // to get source file, line and column info.
+    Dwarf_Line line = die_object.line_buffer[it->second];
+    Dwarf_Error error = DW_DLE_NE;
+
+    char *filename;
+    if (dwarf_linesrc(line, &filename, &error) == DW_DLV_OK) {
+      trace.source.filename = std::string(filename);
+      dwarf_dealloc(fobj.dwarf_handle.get(), filename, DW_DLA_STRING);
+    }
+
+    Dwarf_Unsigned number = 0;
+    if (dwarf_lineno(line, &number, &error) == DW_DLV_OK) {
+      trace.source.line = number;
+    } else {
+      trace.source.line = 0;
+    }
+
+    if (dwarf_lineoff_b(line, &number, &error) == DW_DLV_OK) {
+      trace.source.col = number;
+    } else {
+      trace.source.col = 0;
+    }
+
+    std::vector<std::string> namespace_stack;
+    deep_first_search_by_pc(fobj, die, address, namespace_stack,
+                            inliners_search_cb(trace, fobj, die));
+
+    dwarf_dealloc(fobj.dwarf_handle.get(), die, DW_DLA_DIE);
+
+    return trace;
+  }
+
+public:
+  static int close_dwarf(Dwarf_Debug dwarf) {
+    return dwarf_finish(dwarf, NULL);
+  }
+
+private:
+  bool _dwarf_loaded;
+
+  typedef details::handle<int, details::deleter<int, int, &::close>>
+      dwarf_file_t;
+
+  typedef details::handle<Elf *, details::deleter<int, Elf *, &elf_end>>
+      dwarf_elf_t;
+
+  typedef details::handle<Dwarf_Debug,
+                          details::deleter<int, Dwarf_Debug, &close_dwarf>>
+      dwarf_handle_t;
+
+  typedef std::map<Dwarf_Addr, int> die_linemap_t;
+
+  typedef std::map<Dwarf_Off, Dwarf_Off> die_specmap_t;
+
+  struct die_cache_entry {
+    die_specmap_t spec_section;
+    die_linemap_t line_section;
+    Dwarf_Line *line_buffer;
+    Dwarf_Signed line_count;
+    Dwarf_Line_Context line_context;
+
+    inline bool isEmpty() {
+      return line_buffer == NULL || line_count == 0 || line_context == NULL ||
+             line_section.empty();
+    }
+
+    die_cache_entry() : line_buffer(0), line_count(0), line_context(0) {}
+
+    ~die_cache_entry() {
+      if (line_context) {
+        dwarf_srclines_dealloc_b(line_context);
+      }
+    }
+  };
+
+  typedef std::map<Dwarf_Off, die_cache_entry> die_cache_t;
+
+  typedef std::map<uintptr_t, std::string> symbol_cache_t;
+
+  struct dwarf_fileobject {
+    dwarf_file_t file_handle;
+    dwarf_elf_t elf_handle;
+    dwarf_handle_t dwarf_handle;
+    symbol_cache_t symbol_cache;
+
+    // Die cache
+    die_cache_t die_cache;
+    die_cache_entry *current_cu;
+  };
+
+  typedef details::hashtable<std::string, dwarf_fileobject>::type
+      fobj_dwarf_map_t;
+  fobj_dwarf_map_t _fobj_dwarf_map;
+
+  static bool cstrings_eq(const char *a, const char *b) {
+    if (!a || !b) {
+      return false;
+    }
+    return strcmp(a, b) == 0;
+  }
+
+  dwarf_fileobject &load_object_with_dwarf(const std::string &filename_object) {
+
+    if (!_dwarf_loaded) {
+      // Set the ELF library operating version
+      // If that fails there's nothing we can do
+      _dwarf_loaded = elf_version(EV_CURRENT) != EV_NONE;
+    }
+
+    fobj_dwarf_map_t::iterator it = _fobj_dwarf_map.find(filename_object);
+    if (it != _fobj_dwarf_map.end()) {
+      return it->second;
+    }
+
+    // this new object is empty for now
+    dwarf_fileobject &r = _fobj_dwarf_map[filename_object];
+
+    dwarf_file_t file_handle;
+    file_handle.reset(open(filename_object.c_str(), O_RDONLY));
+    if (file_handle.get() < 0) {
+      return r;
+    }
+
+    // Try to get an ELF handle. We need to read the ELF sections
+    // because we want to see if there is a .gnu_debuglink section
+    // that points to a split debug file
+    dwarf_elf_t elf_handle;
+    elf_handle.reset(elf_begin(file_handle.get(), ELF_C_READ, NULL));
+    if (!elf_handle) {
+      return r;
+    }
+
+    const char *e_ident = elf_getident(elf_handle.get(), 0);
+    if (!e_ident) {
+      return r;
+    }
+
+    // Get the number of sections
+    // We use the new APIs as elf_getshnum is deprecated
+    size_t shdrnum = 0;
+    if (elf_getshdrnum(elf_handle.get(), &shdrnum) == -1) {
+      return r;
+    }
+
+    // Get the index to the string section
+    size_t shdrstrndx = 0;
+    if (elf_getshdrstrndx(elf_handle.get(), &shdrstrndx) == -1) {
+      return r;
+    }
+
+    std::string debuglink;
+    // Iterate through the ELF sections to try to get a gnu_debuglink
+    // note and also to cache the symbol table.
+    // We go the preprocessor way to avoid having to create templated
+    // classes or using gelf (which might throw a compiler error if 64 bit
+    // is not supported
+#define ELF_GET_DATA(ARCH)                                                     \
+  Elf_Scn *elf_section = 0;                                                    \
+  Elf_Data *elf_data = 0;                                                      \
+  Elf##ARCH##_Shdr *section_header = 0;                                        \
+  Elf_Scn *symbol_section = 0;                                                 \
+  size_t symbol_count = 0;                                                     \
+  size_t symbol_strings = 0;                                                   \
+  Elf##ARCH##_Sym *symbol = 0;                                                 \
+  const char *section_name = 0;                                                \
+                                                                               \
+  while ((elf_section = elf_nextscn(elf_handle.get(), elf_section)) != NULL) { \
+    section_header = elf##ARCH##_getshdr(elf_section);                         \
+    if (section_header == NULL) {                                              \
+      return r;                                                                \
+    }                                                                          \
+                                                                               \
+    if ((section_name = elf_strptr(elf_handle.get(), shdrstrndx,               \
+                                   section_header->sh_name)) == NULL) {        \
+      return r;                                                                \
+    }                                                                          \
+                                                                               \
+    if (cstrings_eq(section_name, ".gnu_debuglink")) {                         \
+      elf_data = elf_getdata(elf_section, NULL);                               \
+      if (elf_data && elf_data->d_size > 0) {                                  \
+        debuglink =                                                            \
+            std::string(reinterpret_cast<const char *>(elf_data->d_buf));      \
+      }                                                                        \
+    }                                                                          \
+                                                                               \
+    switch (section_header->sh_type) {                                         \
+    case SHT_SYMTAB:                                                           \
+      symbol_section = elf_section;                                            \
+      symbol_count = section_header->sh_size / section_header->sh_entsize;     \
+      symbol_strings = section_header->sh_link;                                \
+      break;                                                                   \
+                                                                               \
+    /* We use .dynsyms as a last resort, we prefer .symtab */                  \
+    case SHT_DYNSYM:                                                           \
+      if (!symbol_section) {                                                   \
+        symbol_section = elf_section;                                          \
+        symbol_count = section_header->sh_size / section_header->sh_entsize;   \
+        symbol_strings = section_header->sh_link;                              \
+      }                                                                        \
+      break;                                                                   \
+    }                                                                          \
+  }                                                                            \
+                                                                               \
+  if (symbol_section && symbol_count && symbol_strings) {                      \
+    elf_data = elf_getdata(symbol_section, NULL);                              \
+    symbol = reinterpret_cast<Elf##ARCH##_Sym *>(elf_data->d_buf);             \
+    for (size_t i = 0; i < symbol_count; ++i) {                                \
+      int type = ELF##ARCH##_ST_TYPE(symbol->st_info);                         \
+      if (type == STT_FUNC && symbol->st_value > 0) {                          \
+        r.symbol_cache[symbol->st_value] = std::string(                        \
+            elf_strptr(elf_handle.get(), symbol_strings, symbol->st_name));    \
+      }                                                                        \
+      ++symbol;                                                                \
+    }                                                                          \
+  }
+
+    if (e_ident[EI_CLASS] == ELFCLASS32) {
+      ELF_GET_DATA(32)
+    } else if (e_ident[EI_CLASS] == ELFCLASS64) {
+      // libelf might have been built without 64 bit support
+#if __LIBELF64
+      ELF_GET_DATA(64)
+#endif
+    }
+
+    if (!debuglink.empty()) {
+      // We have a debuglink section! Open an elf instance on that
+      // file instead. If we can't open the file, then return
+      // the elf handle we had already opened.
+      dwarf_file_t debuglink_file;
+      debuglink_file.reset(open(debuglink.c_str(), O_RDONLY));
+      if (debuglink_file.get() > 0) {
+        dwarf_elf_t debuglink_elf;
+        debuglink_elf.reset(elf_begin(debuglink_file.get(), ELF_C_READ, NULL));
+
+        // If we have a valid elf handle, return the new elf handle
+        // and file handle and discard the original ones
+        if (debuglink_elf) {
+          elf_handle = move(debuglink_elf);
+          file_handle = move(debuglink_file);
+        }
+      }
+    }
+
+    // Ok, we have a valid ELF handle, let's try to get debug symbols
+    Dwarf_Debug dwarf_debug;
+    Dwarf_Error error = DW_DLE_NE;
+    dwarf_handle_t dwarf_handle;
+
+    int dwarf_result = dwarf_elf_init(elf_handle.get(), DW_DLC_READ, NULL, NULL,
+                                      &dwarf_debug, &error);
+
+    // We don't do any special handling for DW_DLV_NO_ENTRY specially.
+    // If we get an error, or the file doesn't have debug information
+    // we just return.
+    if (dwarf_result != DW_DLV_OK) {
+      return r;
+    }
+
+    dwarf_handle.reset(dwarf_debug);
+
+    r.file_handle = move(file_handle);
+    r.elf_handle = move(elf_handle);
+    r.dwarf_handle = move(dwarf_handle);
+
+    return r;
+  }
+
+  die_cache_entry &get_die_cache(dwarf_fileobject &fobj, Dwarf_Die die) {
+    Dwarf_Error error = DW_DLE_NE;
+
+    // Get the die offset, we use it as the cache key
+    Dwarf_Off die_offset;
+    if (dwarf_dieoffset(die, &die_offset, &error) != DW_DLV_OK) {
+      die_offset = 0;
+    }
+
+    die_cache_t::iterator it = fobj.die_cache.find(die_offset);
+
+    if (it != fobj.die_cache.end()) {
+      fobj.current_cu = &it->second;
+      return it->second;
+    }
+
+    die_cache_entry &de = fobj.die_cache[die_offset];
+    fobj.current_cu = &de;
+
+    Dwarf_Addr line_addr;
+    Dwarf_Small table_count;
+
+    // The addresses in the line section are not fully sorted (they might
+    // be sorted by block of code belonging to the same file), which makes
+    // it necessary to do so before searching is possible.
+    //
+    // As libdwarf allocates a copy of everything, let's get the contents
+    // of the line section and keep it around. We also create a map of
+    // program counter to line table indices so we can search by address
+    // and get the line buffer index.
+    //
+    // To make things more difficult, the same address can span more than
+    // one line, so we need to keep the index pointing to the first line
+    // by using insert instead of the map's [ operator.
+
+    // Get the line context for the DIE
+    if (dwarf_srclines_b(die, 0, &table_count, &de.line_context, &error) ==
+        DW_DLV_OK) {
+      // Get the source lines for this line context, to be deallocated
+      // later
+      if (dwarf_srclines_from_linecontext(de.line_context, &de.line_buffer,
+                                          &de.line_count,
+                                          &error) == DW_DLV_OK) {
+
+        // Add all the addresses to our map
+        for (int i = 0; i < de.line_count; i++) {
+          if (dwarf_lineaddr(de.line_buffer[i], &line_addr, &error) !=
+              DW_DLV_OK) {
+            line_addr = 0;
+          }
+          de.line_section.insert(std::pair<Dwarf_Addr, int>(line_addr, i));
+        }
+      }
+    }
+
+    // For each CU, cache the function DIEs that contain the
+    // DW_AT_specification attribute. When building with -g3 the function
+    // DIEs are separated in declaration and specification, with the
+    // declaration containing only the name and parameters and the
+    // specification the low/high pc and other compiler attributes.
+    //
+    // We cache those specifications so we don't skip over the declarations,
+    // because they have no pc, and we can do namespace resolution for
+    // DWARF function names.
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+    Dwarf_Die current_die = 0;
+    if (dwarf_child(die, &current_die, &error) == DW_DLV_OK) {
+      for (;;) {
+        Dwarf_Die sibling_die = 0;
+
+        Dwarf_Half tag_value;
+        dwarf_tag(current_die, &tag_value, &error);
+
+        if (tag_value == DW_TAG_subprogram ||
+            tag_value == DW_TAG_inlined_subroutine) {
+
+          Dwarf_Bool has_attr = 0;
+          if (dwarf_hasattr(current_die, DW_AT_specification, &has_attr,
+                            &error) == DW_DLV_OK) {
+            if (has_attr) {
+              Dwarf_Attribute attr_mem;
+              if (dwarf_attr(current_die, DW_AT_specification, &attr_mem,
+                             &error) == DW_DLV_OK) {
+                Dwarf_Off spec_offset = 0;
+                if (dwarf_formref(attr_mem, &spec_offset, &error) ==
+                    DW_DLV_OK) {
+                  Dwarf_Off spec_die_offset;
+                  if (dwarf_dieoffset(current_die, &spec_die_offset, &error) ==
+                      DW_DLV_OK) {
+                    de.spec_section[spec_offset] = spec_die_offset;
+                  }
+                }
+              }
+              dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+            }
+          }
+        }
+
+        int result = dwarf_siblingof(dwarf, current_die, &sibling_die, &error);
+        if (result == DW_DLV_ERROR) {
+          break;
+        } else if (result == DW_DLV_NO_ENTRY) {
+          break;
+        }
+
+        if (current_die != die) {
+          dwarf_dealloc(dwarf, current_die, DW_DLA_DIE);
+          current_die = 0;
+        }
+
+        current_die = sibling_die;
+      }
+    }
+    return de;
+  }
+
+  static Dwarf_Die get_referenced_die(Dwarf_Debug dwarf, Dwarf_Die die,
+                                      Dwarf_Half attr, bool global) {
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Attribute attr_mem;
+
+    Dwarf_Die found_die = NULL;
+    if (dwarf_attr(die, attr, &attr_mem, &error) == DW_DLV_OK) {
+      Dwarf_Off offset;
+      int result = 0;
+      if (global) {
+        result = dwarf_global_formref(attr_mem, &offset, &error);
+      } else {
+        result = dwarf_formref(attr_mem, &offset, &error);
+      }
+
+      if (result == DW_DLV_OK) {
+        if (dwarf_offdie(dwarf, offset, &found_die, &error) != DW_DLV_OK) {
+          found_die = NULL;
+        }
+      }
+      dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+    }
+    return found_die;
+  }
+
+  static std::string get_referenced_die_name(Dwarf_Debug dwarf, Dwarf_Die die,
+                                             Dwarf_Half attr, bool global) {
+    Dwarf_Error error = DW_DLE_NE;
+    std::string value;
+
+    Dwarf_Die found_die = get_referenced_die(dwarf, die, attr, global);
+
+    if (found_die) {
+      char *name;
+      if (dwarf_diename(found_die, &name, &error) == DW_DLV_OK) {
+        if (name) {
+          value = std::string(name);
+        }
+        dwarf_dealloc(dwarf, name, DW_DLA_STRING);
+      }
+      dwarf_dealloc(dwarf, found_die, DW_DLA_DIE);
+    }
+
+    return value;
+  }
+
+  // Returns a spec DIE linked to the passed one. The caller should
+  // deallocate the DIE
+  static Dwarf_Die get_spec_die(dwarf_fileobject &fobj, Dwarf_Die die) {
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Off die_offset;
+    if (fobj.current_cu &&
+        dwarf_die_CU_offset(die, &die_offset, &error) == DW_DLV_OK) {
+      die_specmap_t::iterator it =
+          fobj.current_cu->spec_section.find(die_offset);
+
+      // If we have a DIE that completes the current one, check if
+      // that one has the pc we are looking for
+      if (it != fobj.current_cu->spec_section.end()) {
+        Dwarf_Die spec_die = 0;
+        if (dwarf_offdie(dwarf, it->second, &spec_die, &error) == DW_DLV_OK) {
+          return spec_die;
+        }
+      }
+    }
+
+    // Maybe we have an abstract origin DIE with the function information?
+    return get_referenced_die(fobj.dwarf_handle.get(), die,
+                              DW_AT_abstract_origin, true);
+  }
+
+  static bool die_has_pc(dwarf_fileobject &fobj, Dwarf_Die die, Dwarf_Addr pc) {
+    Dwarf_Addr low_pc = 0, high_pc = 0;
+    Dwarf_Half high_pc_form = 0;
+    Dwarf_Form_Class return_class;
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+    bool has_lowpc = false;
+    bool has_highpc = false;
+    bool has_ranges = false;
+
+    if (dwarf_lowpc(die, &low_pc, &error) == DW_DLV_OK) {
+      // If we have a low_pc check if there is a high pc.
+      // If we don't have a high pc this might mean we have a base
+      // address for the ranges list or just an address.
+      has_lowpc = true;
+
+      if (dwarf_highpc_b(die, &high_pc, &high_pc_form, &return_class, &error) ==
+          DW_DLV_OK) {
+        // We do have a high pc. In DWARF 4+ this is an offset from the
+        // low pc, but in earlier versions it's an absolute address.
+
+        has_highpc = true;
+        // In DWARF 2/3 this would be a DW_FORM_CLASS_ADDRESS
+        if (return_class == DW_FORM_CLASS_CONSTANT) {
+          high_pc = low_pc + high_pc;
+        }
+
+        // We have low and high pc, check if our address
+        // is in that range
+        return pc >= low_pc && pc < high_pc;
+      }
+    } else {
+      // Reset the low_pc, in case dwarf_lowpc failing set it to some
+      // undefined value.
+      low_pc = 0;
+    }
+
+    // Check if DW_AT_ranges is present and search for the PC in the
+    // returned ranges list. We always add the low_pc, as it not set it will
+    // be 0, in case we had a DW_AT_low_pc and DW_AT_ranges pair
+    bool result = false;
+
+    Dwarf_Attribute attr;
+    if (dwarf_attr(die, DW_AT_ranges, &attr, &error) == DW_DLV_OK) {
+
+      Dwarf_Off offset;
+      if (dwarf_global_formref(attr, &offset, &error) == DW_DLV_OK) {
+        Dwarf_Ranges *ranges;
+        Dwarf_Signed ranges_count = 0;
+        Dwarf_Unsigned byte_count = 0;
+
+        if (dwarf_get_ranges_a(dwarf, offset, die, &ranges, &ranges_count,
+                               &byte_count, &error) == DW_DLV_OK) {
+          has_ranges = ranges_count != 0;
+          for (int i = 0; i < ranges_count; i++) {
+            if (ranges[i].dwr_addr1 != 0 &&
+                pc >= ranges[i].dwr_addr1 + low_pc &&
+                pc < ranges[i].dwr_addr2 + low_pc) {
+              result = true;
+              break;
+            }
+          }
+          dwarf_ranges_dealloc(dwarf, ranges, ranges_count);
+        }
+      }
+    }
+
+    // Last attempt. We might have a single address set as low_pc.
+    if (!result && low_pc != 0 && pc == low_pc) {
+      result = true;
+    }
+
+    // If we don't have lowpc, highpc and ranges maybe this DIE is a
+    // declaration that relies on a DW_AT_specification DIE that happens
+    // later. Use the specification cache we filled when we loaded this CU.
+    if (!result && (!has_lowpc && !has_highpc && !has_ranges)) {
+      Dwarf_Die spec_die = get_spec_die(fobj, die);
+      if (spec_die) {
+        result = die_has_pc(fobj, spec_die, pc);
+        dwarf_dealloc(dwarf, spec_die, DW_DLA_DIE);
+      }
+    }
+
+    return result;
+  }
+
+  static void get_type(Dwarf_Debug dwarf, Dwarf_Die die, std::string &type) {
+    Dwarf_Error error = DW_DLE_NE;
+
+    Dwarf_Die child = 0;
+    if (dwarf_child(die, &child, &error) == DW_DLV_OK) {
+      get_type(dwarf, child, type);
+    }
+
+    if (child) {
+      type.insert(0, "::");
+      dwarf_dealloc(dwarf, child, DW_DLA_DIE);
+    }
+
+    char *name;
+    if (dwarf_diename(die, &name, &error) == DW_DLV_OK) {
+      type.insert(0, std::string(name));
+      dwarf_dealloc(dwarf, name, DW_DLA_STRING);
+    } else {
+      type.insert(0, "<unknown>");
+    }
+  }
+
+  static std::string get_type_by_signature(Dwarf_Debug dwarf, Dwarf_Die die) {
+    Dwarf_Error error = DW_DLE_NE;
+
+    Dwarf_Sig8 signature;
+    Dwarf_Bool has_attr = 0;
+    if (dwarf_hasattr(die, DW_AT_signature, &has_attr, &error) == DW_DLV_OK) {
+      if (has_attr) {
+        Dwarf_Attribute attr_mem;
+        if (dwarf_attr(die, DW_AT_signature, &attr_mem, &error) == DW_DLV_OK) {
+          if (dwarf_formsig8(attr_mem, &signature, &error) != DW_DLV_OK) {
+            return std::string("<no type signature>");
+          }
+        }
+        dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+      }
+    }
+
+    Dwarf_Unsigned next_cu_header;
+    Dwarf_Sig8 tu_signature;
+    std::string result;
+    bool found = false;
+
+    while (dwarf_next_cu_header_d(dwarf, 0, 0, 0, 0, 0, 0, 0, &tu_signature, 0,
+                                  &next_cu_header, 0, &error) == DW_DLV_OK) {
+
+      if (strncmp(signature.signature, tu_signature.signature, 8) == 0) {
+        Dwarf_Die type_cu_die = 0;
+        if (dwarf_siblingof_b(dwarf, 0, 0, &type_cu_die, &error) == DW_DLV_OK) {
+          Dwarf_Die child_die = 0;
+          if (dwarf_child(type_cu_die, &child_die, &error) == DW_DLV_OK) {
+            get_type(dwarf, child_die, result);
+            found = !result.empty();
+            dwarf_dealloc(dwarf, child_die, DW_DLA_DIE);
+          }
+          dwarf_dealloc(dwarf, type_cu_die, DW_DLA_DIE);
+        }
+      }
+    }
+
+    if (found) {
+      while (dwarf_next_cu_header_d(dwarf, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                                    &next_cu_header, 0, &error) == DW_DLV_OK) {
+        // Reset the cu header state. Unfortunately, libdwarf's
+        // next_cu_header API keeps its own iterator per Dwarf_Debug
+        // that can't be reset. We need to keep fetching elements until
+        // the end.
+      }
+    } else {
+      // If we couldn't resolve the type just print out the signature
+      std::ostringstream string_stream;
+      string_stream << "<0x" << std::hex << std::setfill('0');
+      for (int i = 0; i < 8; ++i) {
+        string_stream << std::setw(2) << std::hex
+                      << (int)(unsigned char)(signature.signature[i]);
+      }
+      string_stream << ">";
+      result = string_stream.str();
+    }
+    return result;
+  }
+
+  struct type_context_t {
+    bool is_const;
+    bool is_typedef;
+    bool has_type;
+    bool has_name;
+    std::string text;
+
+    type_context_t()
+        : is_const(false), is_typedef(false), has_type(false), has_name(false) {
+    }
+  };
+
+  // Types are resolved from right to left: we get the variable name first
+  // and then all specifiers (like const or pointer) in a chain of DW_AT_type
+  // DIEs. Call this function recursively until we get a complete type
+  // string.
+  static void set_parameter_string(dwarf_fileobject &fobj, Dwarf_Die die,
+                                   type_context_t &context) {
+    char *name;
+    Dwarf_Error error = DW_DLE_NE;
+
+    // typedefs contain also the base type, so we skip it and only
+    // print the typedef name
+    if (!context.is_typedef) {
+      if (dwarf_diename(die, &name, &error) == DW_DLV_OK) {
+        if (!context.text.empty()) {
+          context.text.insert(0, " ");
+        }
+        context.text.insert(0, std::string(name));
+        dwarf_dealloc(fobj.dwarf_handle.get(), name, DW_DLA_STRING);
+      }
+    } else {
+      context.is_typedef = false;
+      context.has_type = true;
+      if (context.is_const) {
+        context.text.insert(0, "const ");
+        context.is_const = false;
+      }
+    }
+
+    bool next_type_is_const = false;
+    bool is_keyword = true;
+
+    Dwarf_Half tag = 0;
+    Dwarf_Bool has_attr = 0;
+    if (dwarf_tag(die, &tag, &error) == DW_DLV_OK) {
+      switch (tag) {
+      case DW_TAG_structure_type:
+      case DW_TAG_union_type:
+      case DW_TAG_class_type:
+      case DW_TAG_enumeration_type:
+        context.has_type = true;
+        if (dwarf_hasattr(die, DW_AT_signature, &has_attr, &error) ==
+            DW_DLV_OK) {
+          // If we have a signature it means the type is defined
+          // in .debug_types, so we need to load the DIE pointed
+          // at by the signature and resolve it
+          if (has_attr) {
+            std::string type =
+                get_type_by_signature(fobj.dwarf_handle.get(), die);
+            if (context.is_const)
+              type.insert(0, "const ");
+
+            if (!context.text.empty())
+              context.text.insert(0, " ");
+            context.text.insert(0, type);
+          }
+
+          // Treat enums like typedefs, and skip printing its
+          // base type
+          context.is_typedef = (tag == DW_TAG_enumeration_type);
+        }
+        break;
+      case DW_TAG_const_type:
+        next_type_is_const = true;
+        break;
+      case DW_TAG_pointer_type:
+        context.text.insert(0, "*");
+        break;
+      case DW_TAG_reference_type:
+        context.text.insert(0, "&");
+        break;
+      case DW_TAG_restrict_type:
+        context.text.insert(0, "restrict ");
+        break;
+      case DW_TAG_rvalue_reference_type:
+        context.text.insert(0, "&&");
+        break;
+      case DW_TAG_volatile_type:
+        context.text.insert(0, "volatile ");
+        break;
+      case DW_TAG_typedef:
+        // Propagate the const-ness to the next type
+        // as typedefs are linked to its base type
+        next_type_is_const = context.is_const;
+        context.is_typedef = true;
+        context.has_type = true;
+        break;
+      case DW_TAG_base_type:
+        context.has_type = true;
+        break;
+      case DW_TAG_formal_parameter:
+        context.has_name = true;
+        break;
+      default:
+        is_keyword = false;
+        break;
+      }
+    }
+
+    if (!is_keyword && context.is_const) {
+      context.text.insert(0, "const ");
+    }
+
+    context.is_const = next_type_is_const;
+
+    Dwarf_Die ref =
+        get_referenced_die(fobj.dwarf_handle.get(), die, DW_AT_type, true);
+    if (ref) {
+      set_parameter_string(fobj, ref, context);
+      dwarf_dealloc(fobj.dwarf_handle.get(), ref, DW_DLA_DIE);
+    }
+
+    if (!context.has_type && context.has_name) {
+      context.text.insert(0, "void ");
+      context.has_type = true;
+    }
+  }
+
+  // Resolve the function return type and parameters
+  static void set_function_parameters(std::string &function_name,
+                                      std::vector<std::string> &ns,
+                                      dwarf_fileobject &fobj, Dwarf_Die die) {
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Die current_die = 0;
+    std::string parameters;
+    bool has_spec = true;
+    // Check if we have a spec DIE. If we do we use it as it contains
+    // more information, like parameter names.
+    Dwarf_Die spec_die = get_spec_die(fobj, die);
+    if (!spec_die) {
+      has_spec = false;
+      spec_die = die;
+    }
+
+    std::vector<std::string>::const_iterator it = ns.begin();
+    std::string ns_name;
+    for (it = ns.begin(); it < ns.end(); ++it) {
+      ns_name.append(*it).append("::");
+    }
+
+    if (!ns_name.empty()) {
+      function_name.insert(0, ns_name);
+    }
+
+    // See if we have a function return type. It can be either on the
+    // current die or in its spec one (usually true for inlined functions)
+    std::string return_type =
+        get_referenced_die_name(dwarf, die, DW_AT_type, true);
+    if (return_type.empty()) {
+      return_type = get_referenced_die_name(dwarf, spec_die, DW_AT_type, true);
+    }
+    if (!return_type.empty()) {
+      return_type.append(" ");
+      function_name.insert(0, return_type);
+    }
+
+    if (dwarf_child(spec_die, &current_die, &error) == DW_DLV_OK) {
+      for (;;) {
+        Dwarf_Die sibling_die = 0;
+
+        Dwarf_Half tag_value;
+        dwarf_tag(current_die, &tag_value, &error);
+
+        if (tag_value == DW_TAG_formal_parameter) {
+          // Ignore artificial (ie, compiler generated) parameters
+          bool is_artificial = false;
+          Dwarf_Attribute attr_mem;
+          if (dwarf_attr(current_die, DW_AT_artificial, &attr_mem, &error) ==
+              DW_DLV_OK) {
+            Dwarf_Bool flag = 0;
+            if (dwarf_formflag(attr_mem, &flag, &error) == DW_DLV_OK) {
+              is_artificial = flag != 0;
+            }
+            dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+          }
+
+          if (!is_artificial) {
+            type_context_t context;
+            set_parameter_string(fobj, current_die, context);
+
+            if (parameters.empty()) {
+              parameters.append("(");
+            } else {
+              parameters.append(", ");
+            }
+            parameters.append(context.text);
+          }
+        }
+
+        int result = dwarf_siblingof(dwarf, current_die, &sibling_die, &error);
+        if (result == DW_DLV_ERROR) {
+          break;
+        } else if (result == DW_DLV_NO_ENTRY) {
+          break;
+        }
+
+        if (current_die != die) {
+          dwarf_dealloc(dwarf, current_die, DW_DLA_DIE);
+          current_die = 0;
+        }
+
+        current_die = sibling_die;
+      }
+    }
+    if (parameters.empty())
+      parameters = "(";
+    parameters.append(")");
+
+    // If we got a spec DIE we need to deallocate it
+    if (has_spec)
+      dwarf_dealloc(dwarf, spec_die, DW_DLA_DIE);
+
+    function_name.append(parameters);
+  }
+
+  // defined here because in C++98, template function cannot take locally
+  // defined types... grrr.
+  struct inliners_search_cb {
+    void operator()(Dwarf_Die die, std::vector<std::string> &ns) {
+      Dwarf_Error error = DW_DLE_NE;
+      Dwarf_Half tag_value;
+      Dwarf_Attribute attr_mem;
+      Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+
+      dwarf_tag(die, &tag_value, &error);
+
+      switch (tag_value) {
+        char *name;
+      case DW_TAG_subprogram:
+        if (!trace.source.function.empty())
+          break;
+        if (dwarf_diename(die, &name, &error) == DW_DLV_OK) {
+          trace.source.function = std::string(name);
+          dwarf_dealloc(dwarf, name, DW_DLA_STRING);
+        } else {
+          // We don't have a function name in this DIE.
+          // Check if there is a referenced non-defining
+          // declaration.
+          trace.source.function =
+              get_referenced_die_name(dwarf, die, DW_AT_abstract_origin, true);
+          if (trace.source.function.empty()) {
+            trace.source.function =
+                get_referenced_die_name(dwarf, die, DW_AT_specification, true);
+          }
+        }
+
+        // Append the function parameters, if available
+        set_function_parameters(trace.source.function, ns, fobj, die);
+
+        // If the object function name is empty, it's possible that
+        // there is no dynamic symbol table (maybe the executable
+        // was stripped or not built with -rdynamic). See if we have
+        // a DWARF linkage name to use instead. We try both
+        // linkage_name and MIPS_linkage_name because the MIPS tag
+        // was the unofficial one until it was adopted in DWARF4.
+        // Old gcc versions generate MIPS_linkage_name
+        if (trace.object_function.empty()) {
+          details::demangler demangler;
+
+          if (dwarf_attr(die, DW_AT_linkage_name, &attr_mem, &error) !=
+              DW_DLV_OK) {
+            if (dwarf_attr(die, DW_AT_MIPS_linkage_name, &attr_mem, &error) !=
+                DW_DLV_OK) {
+              break;
+            }
+          }
+
+          char *linkage;
+          if (dwarf_formstring(attr_mem, &linkage, &error) == DW_DLV_OK) {
+            trace.object_function = demangler.demangle(linkage);
+            dwarf_dealloc(dwarf, linkage, DW_DLA_STRING);
+          }
+          dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+        }
+        break;
+
+      case DW_TAG_inlined_subroutine:
+        ResolvedTrace::SourceLoc sloc;
+
+        if (dwarf_diename(die, &name, &error) == DW_DLV_OK) {
+          sloc.function = std::string(name);
+          dwarf_dealloc(dwarf, name, DW_DLA_STRING);
+        } else {
+          // We don't have a name for this inlined DIE, it could
+          // be that there is an abstract origin instead.
+          // Get the DW_AT_abstract_origin value, which is a
+          // reference to the source DIE and try to get its name
+          sloc.function =
+              get_referenced_die_name(dwarf, die, DW_AT_abstract_origin, true);
+        }
+
+        set_function_parameters(sloc.function, ns, fobj, die);
+
+        std::string file = die_call_file(dwarf, die, cu_die);
+        if (!file.empty())
+          sloc.filename = file;
+
+        Dwarf_Unsigned number = 0;
+        if (dwarf_attr(die, DW_AT_call_line, &attr_mem, &error) == DW_DLV_OK) {
+          if (dwarf_formudata(attr_mem, &number, &error) == DW_DLV_OK) {
+            sloc.line = number;
+          }
+          dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+        }
+
+        if (dwarf_attr(die, DW_AT_call_column, &attr_mem, &error) ==
+            DW_DLV_OK) {
+          if (dwarf_formudata(attr_mem, &number, &error) == DW_DLV_OK) {
+            sloc.col = number;
+          }
+          dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+        }
+
+        trace.inliners.push_back(sloc);
+        break;
+      };
+    }
+    ResolvedTrace &trace;
+    dwarf_fileobject &fobj;
+    Dwarf_Die cu_die;
+    inliners_search_cb(ResolvedTrace &t, dwarf_fileobject &f, Dwarf_Die c)
+        : trace(t), fobj(f), cu_die(c) {}
+  };
+
+  static Dwarf_Die find_fundie_by_pc(dwarf_fileobject &fobj,
+                                     Dwarf_Die parent_die, Dwarf_Addr pc,
+                                     Dwarf_Die result) {
+    Dwarf_Die current_die = 0;
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+
+    if (dwarf_child(parent_die, &current_die, &error) != DW_DLV_OK) {
+      return NULL;
+    }
+
+    for (;;) {
+      Dwarf_Die sibling_die = 0;
+      Dwarf_Half tag_value;
+      dwarf_tag(current_die, &tag_value, &error);
+
+      switch (tag_value) {
+      case DW_TAG_subprogram:
+      case DW_TAG_inlined_subroutine:
+        if (die_has_pc(fobj, current_die, pc)) {
+          return current_die;
+        }
+      };
+      bool declaration = false;
+      Dwarf_Attribute attr_mem;
+      if (dwarf_attr(current_die, DW_AT_declaration, &attr_mem, &error) ==
+          DW_DLV_OK) {
+        Dwarf_Bool flag = 0;
+        if (dwarf_formflag(attr_mem, &flag, &error) == DW_DLV_OK) {
+          declaration = flag != 0;
+        }
+        dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+      }
+
+      if (!declaration) {
+        // let's be curious and look deeper in the tree, functions are
+        // not necessarily at the first level, but might be nested
+        // inside a namespace, structure, a function, an inlined
+        // function etc.
+        Dwarf_Die die_mem = 0;
+        Dwarf_Die indie = find_fundie_by_pc(fobj, current_die, pc, die_mem);
+        if (indie) {
+          result = die_mem;
+          return result;
+        }
+      }
+
+      int res = dwarf_siblingof(dwarf, current_die, &sibling_die, &error);
+      if (res == DW_DLV_ERROR) {
+        return NULL;
+      } else if (res == DW_DLV_NO_ENTRY) {
+        break;
+      }
+
+      if (current_die != parent_die) {
+        dwarf_dealloc(dwarf, current_die, DW_DLA_DIE);
+        current_die = 0;
+      }
+
+      current_die = sibling_die;
+    }
+    return NULL;
+  }
+
+  template <typename CB>
+  static bool deep_first_search_by_pc(dwarf_fileobject &fobj,
+                                      Dwarf_Die parent_die, Dwarf_Addr pc,
+                                      std::vector<std::string> &ns, CB cb) {
+    Dwarf_Die current_die = 0;
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+    Dwarf_Error error = DW_DLE_NE;
+
+    if (dwarf_child(parent_die, &current_die, &error) != DW_DLV_OK) {
+      return false;
+    }
+
+    bool branch_has_pc = false;
+    bool has_namespace = false;
+    for (;;) {
+      Dwarf_Die sibling_die = 0;
+
+      Dwarf_Half tag;
+      if (dwarf_tag(current_die, &tag, &error) == DW_DLV_OK) {
+        if (tag == DW_TAG_namespace || tag == DW_TAG_class_type) {
+          char *ns_name = NULL;
+          if (dwarf_diename(current_die, &ns_name, &error) == DW_DLV_OK) {
+            if (ns_name) {
+              ns.push_back(std::string(ns_name));
+            } else {
+              ns.push_back("<unknown>");
+            }
+            dwarf_dealloc(dwarf, ns_name, DW_DLA_STRING);
+          } else {
+            ns.push_back("<unknown>");
+          }
+          has_namespace = true;
+        }
+      }
+
+      bool declaration = false;
+      Dwarf_Attribute attr_mem;
+      if (tag != DW_TAG_class_type &&
+          dwarf_attr(current_die, DW_AT_declaration, &attr_mem, &error) ==
+              DW_DLV_OK) {
+        Dwarf_Bool flag = 0;
+        if (dwarf_formflag(attr_mem, &flag, &error) == DW_DLV_OK) {
+          declaration = flag != 0;
+        }
+        dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+      }
+
+      if (!declaration) {
+        // let's be curious and look deeper in the tree, function are
+        // not necessarily at the first level, but might be nested
+        // inside a namespace, structure, a function, an inlined
+        // function etc.
+        branch_has_pc = deep_first_search_by_pc(fobj, current_die, pc, ns, cb);
+      }
+
+      if (!branch_has_pc) {
+        branch_has_pc = die_has_pc(fobj, current_die, pc);
+      }
+
+      if (branch_has_pc) {
+        cb(current_die, ns);
+      }
+
+      int result = dwarf_siblingof(dwarf, current_die, &sibling_die, &error);
+      if (result == DW_DLV_ERROR) {
+        return false;
+      } else if (result == DW_DLV_NO_ENTRY) {
+        break;
+      }
+
+      if (current_die != parent_die) {
+        dwarf_dealloc(dwarf, current_die, DW_DLA_DIE);
+        current_die = 0;
+      }
+
+      if (has_namespace) {
+        has_namespace = false;
+        ns.pop_back();
+      }
+      current_die = sibling_die;
+    }
+
+    if (has_namespace) {
+      ns.pop_back();
+    }
+    return branch_has_pc;
+  }
+
+  static std::string die_call_file(Dwarf_Debug dwarf, Dwarf_Die die,
+                                   Dwarf_Die cu_die) {
+    Dwarf_Attribute attr_mem;
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Unsigned file_index;
+
+    std::string file;
+
+    if (dwarf_attr(die, DW_AT_call_file, &attr_mem, &error) == DW_DLV_OK) {
+      if (dwarf_formudata(attr_mem, &file_index, &error) != DW_DLV_OK) {
+        file_index = 0;
+      }
+      dwarf_dealloc(dwarf, attr_mem, DW_DLA_ATTR);
+
+      if (file_index == 0) {
+        return file;
+      }
+
+      char **srcfiles = 0;
+      Dwarf_Signed file_count = 0;
+      if (dwarf_srcfiles(cu_die, &srcfiles, &file_count, &error) == DW_DLV_OK) {
+        if (file_count > 0 && file_index <= static_cast<Dwarf_Unsigned>(file_count)) {
+          file = std::string(srcfiles[file_index - 1]);
+	}
+
+        // Deallocate all strings!
+        for (int i = 0; i < file_count; ++i) {
+          dwarf_dealloc(dwarf, srcfiles[i], DW_DLA_STRING);
+        }
+        dwarf_dealloc(dwarf, srcfiles, DW_DLA_LIST);
+      }
+    }
+    return file;
+  }
+
+  Dwarf_Die find_die(dwarf_fileobject &fobj, Dwarf_Addr addr) {
+    // Let's get to work! First see if we have a debug_aranges section so
+    // we can speed up the search
+
+    Dwarf_Debug dwarf = fobj.dwarf_handle.get();
+    Dwarf_Error error = DW_DLE_NE;
+    Dwarf_Arange *aranges;
+    Dwarf_Signed arange_count;
+
+    Dwarf_Die returnDie;
+    bool found = false;
+    if (dwarf_get_aranges(dwarf, &aranges, &arange_count, &error) !=
+        DW_DLV_OK) {
+      aranges = NULL;
+    }
+
+    if (aranges) {
+      // We have aranges. Get the one where our address is.
+      Dwarf_Arange arange;
+      if (dwarf_get_arange(aranges, arange_count, addr, &arange, &error) ==
+          DW_DLV_OK) {
+
+        // We found our address. Get the compilation-unit DIE offset
+        // represented by the given address range.
+        Dwarf_Off cu_die_offset;
+        if (dwarf_get_cu_die_offset(arange, &cu_die_offset, &error) ==
+            DW_DLV_OK) {
+          // Get the DIE at the offset returned by the aranges search.
+          // We set is_info to 1 to specify that the offset is from
+          // the .debug_info section (and not .debug_types)
+          int dwarf_result =
+              dwarf_offdie_b(dwarf, cu_die_offset, 1, &returnDie, &error);
+
+          found = dwarf_result == DW_DLV_OK;
+        }
+        dwarf_dealloc(dwarf, arange, DW_DLA_ARANGE);
+      }
+    }
+
+    if (found)
+      return returnDie; // The caller is responsible for freeing the die
+
+    // The search for aranges failed. Try to find our address by scanning
+    // all compilation units.
+    Dwarf_Unsigned next_cu_header;
+    Dwarf_Half tag = 0;
+    returnDie = 0;
+
+    while (!found &&
+           dwarf_next_cu_header_d(dwarf, 1, 0, 0, 0, 0, 0, 0, 0, 0,
+                                  &next_cu_header, 0, &error) == DW_DLV_OK) {
+
+      if (returnDie)
+        dwarf_dealloc(dwarf, returnDie, DW_DLA_DIE);
+
+      if (dwarf_siblingof(dwarf, 0, &returnDie, &error) == DW_DLV_OK) {
+        if ((dwarf_tag(returnDie, &tag, &error) == DW_DLV_OK) &&
+            tag == DW_TAG_compile_unit) {
+          if (die_has_pc(fobj, returnDie, addr)) {
+            found = true;
+          }
+        }
+      }
+    }
+
+    if (found) {
+      while (dwarf_next_cu_header_d(dwarf, 1, 0, 0, 0, 0, 0, 0, 0, 0,
+                                    &next_cu_header, 0, &error) == DW_DLV_OK) {
+        // Reset the cu header state. Libdwarf's next_cu_header API
+        // keeps its own iterator per Dwarf_Debug that can't be reset.
+        // We need to keep fetching elements until the end.
+      }
+    }
+
+    if (found)
+      return returnDie;
+
+    // We couldn't find any compilation units with ranges or a high/low pc.
+    // Try again by looking at all DIEs in all compilation units.
+    Dwarf_Die cudie;
+    while (dwarf_next_cu_header_d(dwarf, 1, 0, 0, 0, 0, 0, 0, 0, 0,
+                                  &next_cu_header, 0, &error) == DW_DLV_OK) {
+      if (dwarf_siblingof(dwarf, 0, &cudie, &error) == DW_DLV_OK) {
+        Dwarf_Die die_mem = 0;
+        Dwarf_Die resultDie = find_fundie_by_pc(fobj, cudie, addr, die_mem);
+
+        if (resultDie) {
+          found = true;
+          break;
+        }
+      }
+    }
+
+    if (found) {
+      while (dwarf_next_cu_header_d(dwarf, 1, 0, 0, 0, 0, 0, 0, 0, 0,
+                                    &next_cu_header, 0, &error) == DW_DLV_OK) {
+        // Reset the cu header state. Libdwarf's next_cu_header API
+        // keeps its own iterator per Dwarf_Debug that can't be reset.
+        // We need to keep fetching elements until the end.
+      }
+    }
+
+    if (found)
+      return cudie;
+
+    // We failed.
+    return NULL;
+  }
+};
+#endif // BACKWARD_HAS_DWARF == 1
+
+template <>
+class TraceResolverImpl<system_tag::linux_tag>
+    : public TraceResolverLinuxImpl<trace_resolver_tag::current> {};
+
+#endif // BACKWARD_SYSTEM_LINUX
+
+#ifdef BACKWARD_SYSTEM_DARWIN
+
+template <typename STACKTRACE_TAG> class TraceResolverDarwinImpl;
+
+template <>
+class TraceResolverDarwinImpl<trace_resolver_tag::backtrace_symbol>
+    : public TraceResolverImplBase {
+public:
+  void load_addresses(void *const*addresses, int address_count) override {
+    if (address_count == 0) {
+      return;
+    }
+    _symbols.reset(backtrace_symbols(addresses, address_count));
+  }
+
+  ResolvedTrace resolve(ResolvedTrace trace) override {
+    // parse:
+    // <n>  <file>  <addr>  <mangled-name> + <offset>
+    char *filename = _symbols[trace.idx];
+
+    // skip "<n>  "
+    while (*filename && *filename != ' ')
+      filename++;
+    while (*filename == ' ')
+      filename++;
+
+    // find start of <mangled-name> from end (<file> may contain a space)
+    char *p = filename + strlen(filename) - 1;
+    // skip to start of " + <offset>"
+    while (p > filename && *p != ' ')
+      p--;
+    while (p > filename && *p == ' ')
+      p--;
+    while (p > filename && *p != ' ')
+      p--;
+    while (p > filename && *p == ' ')
+      p--;
+    char *funcname_end = p + 1;
+
+    // skip to start of "<manged-name>"
+    while (p > filename && *p != ' ')
+      p--;
+    char *funcname = p + 1;
+
+    // skip to start of "  <addr>  "
+    while (p > filename && *p == ' ')
+      p--;
+    while (p > filename && *p != ' ')
+      p--;
+    while (p > filename && *p == ' ')
+      p--;
+
+    // skip "<file>", handling the case where it contains a
+    char *filename_end = p + 1;
+    if (p == filename) {
+      // something went wrong, give up
+      filename_end = filename + strlen(filename);
+      funcname = filename_end;
+    }
+    trace.object_filename.assign(
+        filename, filename_end); // ok even if filename_end is the ending \0
+                                 // (then we assign entire string)
+
+    if (*funcname) { // if it's not end of string
+      *funcname_end = '\0';
+
+      trace.object_function = this->demangle(funcname);
+      trace.object_function += " ";
+      trace.object_function += (funcname_end + 1);
+      trace.source.function = trace.object_function; // we cannot do better.
+    }
+    return trace;
+  }
+
+private:
+  details::handle<char **> _symbols;
+};
+
+template <>
+class TraceResolverImpl<system_tag::darwin_tag>
+    : public TraceResolverDarwinImpl<trace_resolver_tag::current> {};
+
+#endif // BACKWARD_SYSTEM_DARWIN
+
+#ifdef BACKWARD_SYSTEM_WINDOWS
+
+// Load all symbol info
+// Based on:
+// https://stackoverflow.com/questions/6205981/windows-c-stack-trace-from-a-running-app/28276227#28276227
+
+struct module_data {
+  std::string image_name;
+  std::string module_name;
+  void *base_address;
+  DWORD load_size;
+};
+
+class get_mod_info {
+  HANDLE process;
+  static const int buffer_length = 4096;
+
+public:
+  get_mod_info(HANDLE h) : process(h) {}
+
+  module_data operator()(HMODULE module) {
+    module_data ret;
+    char temp[buffer_length];
+    MODULEINFO mi;
+
+    GetModuleInformation(process, module, &mi, sizeof(mi));
+    ret.base_address = mi.lpBaseOfDll;
+    ret.load_size = mi.SizeOfImage;
+
+    GetModuleFileNameExA(process, module, temp, sizeof(temp));
+    ret.image_name = temp;
+    GetModuleBaseNameA(process, module, temp, sizeof(temp));
+    ret.module_name = temp;
+    std::vector<char> img(ret.image_name.begin(), ret.image_name.end());
+    std::vector<char> mod(ret.module_name.begin(), ret.module_name.end());
+    SymLoadModule64(process, 0, &img[0], &mod[0], (DWORD64)ret.base_address,
+                    ret.load_size);
+    return ret;
+  }
+};
+
+template <> class TraceResolverImpl<system_tag::windows_tag>
+    : public TraceResolverImplBase {
+public:
+  TraceResolverImpl() {
+
+    HANDLE process = GetCurrentProcess();
+
+    std::vector<module_data> modules;
+    DWORD cbNeeded;
+    std::vector<HMODULE> module_handles(1);
+    SymInitialize(process, NULL, false);
+    DWORD symOptions = SymGetOptions();
+    symOptions |= SYMOPT_LOAD_LINES | SYMOPT_UNDNAME;
+    SymSetOptions(symOptions);
+    EnumProcessModules(process, &module_handles[0],
+                       module_handles.size() * sizeof(HMODULE), &cbNeeded);
+    module_handles.resize(cbNeeded / sizeof(HMODULE));
+    EnumProcessModules(process, &module_handles[0],
+                       module_handles.size() * sizeof(HMODULE), &cbNeeded);
+    std::transform(module_handles.begin(), module_handles.end(),
+                   std::back_inserter(modules), get_mod_info(process));
+    void *base = modules[0].base_address;
+    IMAGE_NT_HEADERS *h = ImageNtHeader(base);
+    image_type = h->FileHeader.Machine;
+  }
+
+  static const int max_sym_len = 255;
+  struct symbol_t {
+    SYMBOL_INFO sym;
+    char buffer[max_sym_len];
+  } sym;
+
+  DWORD64 displacement;
+
+  ResolvedTrace resolve(ResolvedTrace t) override {
+    HANDLE process = GetCurrentProcess();
+
+    char name[256];
+
+    memset(&sym, 0, sizeof(sym));
+    sym.sym.SizeOfStruct = sizeof(SYMBOL_INFO);
+    sym.sym.MaxNameLen = max_sym_len;
+
+    if (!SymFromAddr(process, (ULONG64)t.addr, &displacement, &sym.sym)) {
+      // TODO:  error handling everywhere
+      char* lpMsgBuf;
+      DWORD dw = GetLastError();
+
+      if (FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                         NULL, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                         (char*)&lpMsgBuf, 0, NULL)) {
+        std::fprintf(stderr, "%s\n", lpMsgBuf);
+        LocalFree(lpMsgBuf);
+      }
+
+      // abort();
+    }
+    UnDecorateSymbolName(sym.sym.Name, (PSTR)name, 256, UNDNAME_COMPLETE);
+
+    DWORD offset = 0;
+    IMAGEHLP_LINE line;
+    if (SymGetLineFromAddr(process, (ULONG64)t.addr, &offset, &line)) {
+      t.object_filename = line.FileName;
+      t.source.filename = line.FileName;
+      t.source.line = line.LineNumber;
+      t.source.col = offset;
+    }
+
+    t.source.function = name;
+    t.object_filename = "";
+    t.object_function = name;
+
+    return t;
+  }
+
+  DWORD machine_type() const { return image_type; }
+
+private:
+  DWORD image_type;
+};
+
+#endif
+
+class TraceResolver : public TraceResolverImpl<system_tag::current_tag> {};
+
+/*************** CODE SNIPPET ***************/
+
+class SourceFile {
+public:
+  typedef std::vector<std::pair<unsigned, std::string>> lines_t;
+
+  SourceFile() {}
+  SourceFile(const std::string &path) {
+    // 1. If BACKWARD_CXX_SOURCE_PREFIXES is set then assume it contains
+    //    a colon-separated list of path prefixes.  Try prepending each
+    //    to the given path until a valid file is found.
+    const std::vector<std::string> &prefixes = get_paths_from_env_variable();
+    for (size_t i = 0; i < prefixes.size(); ++i) {
+      // Double slashes (//) should not be a problem.
+      std::string new_path = prefixes[i] + '/' + path;
+      _file.reset(new std::ifstream(new_path.c_str()));
+      if (is_open())
+        break;
+    }
+    // 2. If no valid file found then fallback to opening the path as-is.
+    if (!_file || !is_open()) {
+      _file.reset(new std::ifstream(path.c_str()));
+    }
+  }
+  bool is_open() const { return _file->is_open(); }
+
+  lines_t &get_lines(unsigned line_start, unsigned line_count, lines_t &lines) {
+    using namespace std;
+    // This function make uses of the dumbest algo ever:
+    //	1) seek(0)
+    //	2) read lines one by one and discard until line_start
+    //	3) read line one by one until line_start + line_count
+    //
+    // If you are getting snippets many time from the same file, it is
+    // somewhat a waste of CPU, feel free to benchmark and propose a
+    // better solution ;)
+
+    _file->clear();
+    _file->seekg(0);
+    string line;
+    unsigned line_idx;
+
+    for (line_idx = 1; line_idx < line_start; ++line_idx) {
+      std::getline(*_file, line);
+      if (!*_file) {
+        return lines;
+      }
+    }
+
+    // think of it like a lambda in C++98 ;)
+    // but look, I will reuse it two times!
+    // What a good boy am I.
+    struct isspace {
+      bool operator()(char c) { return std::isspace(c); }
+    };
+
+    bool started = false;
+    for (; line_idx < line_start + line_count; ++line_idx) {
+      getline(*_file, line);
+      if (!*_file) {
+        return lines;
+      }
+      if (!started) {
+        if (std::find_if(line.begin(), line.end(), not_isspace()) == line.end())
+          continue;
+        started = true;
+      }
+      lines.push_back(make_pair(line_idx, line));
+    }
+
+    lines.erase(
+        std::find_if(lines.rbegin(), lines.rend(), not_isempty()).base(),
+        lines.end());
+    return lines;
+  }
+
+  lines_t get_lines(unsigned line_start, unsigned line_count) {
+    lines_t lines;
+    return get_lines(line_start, line_count, lines);
+  }
+
+  // there is no find_if_not in C++98, lets do something crappy to
+  // workaround.
+  struct not_isspace {
+    bool operator()(char c) { return !std::isspace(c); }
+  };
+  // and define this one here because C++98 is not happy with local defined
+  // struct passed to template functions, fuuuu.
+  struct not_isempty {
+    bool operator()(const lines_t::value_type &p) {
+      return !(std::find_if(p.second.begin(), p.second.end(), not_isspace()) ==
+               p.second.end());
+    }
+  };
+
+  void swap(SourceFile &b) { _file.swap(b._file); }
+
+#ifdef BACKWARD_ATLEAST_CXX11
+  SourceFile(SourceFile &&from) : _file(nullptr) { swap(from); }
+  SourceFile &operator=(SourceFile &&from) {
+    swap(from);
+    return *this;
+  }
+#else
+  explicit SourceFile(const SourceFile &from) {
+    // some sort of poor man's move semantic.
+    swap(const_cast<SourceFile &>(from));
+  }
+  SourceFile &operator=(const SourceFile &from) {
+    // some sort of poor man's move semantic.
+    swap(const_cast<SourceFile &>(from));
+    return *this;
+  }
+#endif
+
+private:
+  details::handle<std::ifstream *, details::default_delete<std::ifstream *>>
+      _file;
+
+  std::vector<std::string> get_paths_from_env_variable_impl() {
+    std::vector<std::string> paths;
+    const char *prefixes_str = std::getenv("BACKWARD_CXX_SOURCE_PREFIXES");
+    if (prefixes_str && prefixes_str[0]) {
+      paths = details::split_source_prefixes(prefixes_str);
+    }
+    return paths;
+  }
+
+  const std::vector<std::string> &get_paths_from_env_variable() {
+    static std::vector<std::string> paths = get_paths_from_env_variable_impl();
+    return paths;
+  }
+
+#ifdef BACKWARD_ATLEAST_CXX11
+  SourceFile(const SourceFile &) = delete;
+  SourceFile &operator=(const SourceFile &) = delete;
+#endif
+};
+
+class SnippetFactory {
+public:
+  typedef SourceFile::lines_t lines_t;
+
+  lines_t get_snippet(const std::string &filename, unsigned line_start,
+                      unsigned context_size) {
+
+    SourceFile &src_file = get_src_file(filename);
+    unsigned start = line_start - context_size / 2;
+    return src_file.get_lines(start, context_size);
+  }
+
+  lines_t get_combined_snippet(const std::string &filename_a, unsigned line_a,
+                               const std::string &filename_b, unsigned line_b,
+                               unsigned context_size) {
+    SourceFile &src_file_a = get_src_file(filename_a);
+    SourceFile &src_file_b = get_src_file(filename_b);
+
+    lines_t lines =
+        src_file_a.get_lines(line_a - context_size / 4, context_size / 2);
+    src_file_b.get_lines(line_b - context_size / 4, context_size / 2, lines);
+    return lines;
+  }
+
+  lines_t get_coalesced_snippet(const std::string &filename, unsigned line_a,
+                                unsigned line_b, unsigned context_size) {
+    SourceFile &src_file = get_src_file(filename);
+
+    using std::max;
+    using std::min;
+    unsigned a = min(line_a, line_b);
+    unsigned b = max(line_a, line_b);
+
+    if ((b - a) < (context_size / 3)) {
+      return src_file.get_lines((a + b - context_size + 1) / 2, context_size);
+    }
+
+    lines_t lines = src_file.get_lines(a - context_size / 4, context_size / 2);
+    src_file.get_lines(b - context_size / 4, context_size / 2, lines);
+    return lines;
+  }
+
+private:
+  typedef details::hashtable<std::string, SourceFile>::type src_files_t;
+  src_files_t _src_files;
+
+  SourceFile &get_src_file(const std::string &filename) {
+    src_files_t::iterator it = _src_files.find(filename);
+    if (it != _src_files.end()) {
+      return it->second;
+    }
+    SourceFile &new_src_file = _src_files[filename];
+    new_src_file = SourceFile(filename);
+    return new_src_file;
+  }
+};
+
+/*************** PRINTER ***************/
+
+namespace ColorMode {
+enum type { automatic, never, always };
+}
+
+class cfile_streambuf : public std::streambuf {
+public:
+  cfile_streambuf(FILE *_sink) : sink(_sink) {}
+  int_type underflow() override { return traits_type::eof(); }
+  int_type overflow(int_type ch) override {
+    if (traits_type::not_eof(ch) && fputc(ch, sink) != EOF) {
+      return ch;
+    }
+    return traits_type::eof();
+  }
+
+  std::streamsize xsputn(const char_type *s, std::streamsize count) override {
+    return static_cast<std::streamsize>(
+        fwrite(s, sizeof *s, static_cast<size_t>(count), sink));
+  }
+
+#ifdef BACKWARD_ATLEAST_CXX11
+public:
+  cfile_streambuf(const cfile_streambuf &) = delete;
+  cfile_streambuf &operator=(const cfile_streambuf &) = delete;
+#else
+private:
+  cfile_streambuf(const cfile_streambuf &);
+  cfile_streambuf &operator=(const cfile_streambuf &);
+#endif
+
+private:
+  FILE *sink;
+  std::vector<char> buffer;
+};
+
+#ifdef BACKWARD_SYSTEM_LINUX
+
+namespace Color {
+enum type { yellow = 33, purple = 35, reset = 39 };
+} // namespace Color
+
+class Colorize {
+public:
+  Colorize(std::ostream &os) : _os(os), _reset(false), _enabled(false) {}
+
+  void activate(ColorMode::type mode) { _enabled = mode == ColorMode::always; }
+
+  void activate(ColorMode::type mode, FILE *fp) { activate(mode, fileno(fp)); }
+
+  void set_color(Color::type ccode) {
+    if (!_enabled)
+      return;
+
+    // I assume that the terminal can handle basic colors. Seriously I
+    // don't want to deal with all the termcap shit.
+    _os << "\033[" << static_cast<int>(ccode) << "m";
+    _reset = (ccode != Color::reset);
+  }
+
+  ~Colorize() {
+    if (_reset) {
+      set_color(Color::reset);
+    }
+  }
+
+private:
+  void activate(ColorMode::type mode, int fd) {
+    activate(mode == ColorMode::automatic && isatty(fd) ? ColorMode::always
+                                                        : mode);
+  }
+
+  std::ostream &_os;
+  bool _reset;
+  bool _enabled;
+};
+
+#else // ndef BACKWARD_SYSTEM_LINUX
+
+namespace Color {
+enum type { yellow = 0, purple = 0, reset = 0 };
+} // namespace Color
+
+class Colorize {
+public:
+  Colorize(std::ostream &) {}
+  void activate(ColorMode::type) {}
+  void activate(ColorMode::type, FILE *) {}
+  void set_color(Color::type) {}
+};
+
+#endif // BACKWARD_SYSTEM_LINUX
+
+class Printer {
+public:
+  bool snippet;
+  ColorMode::type color_mode;
+  bool address;
+  bool object;
+  int inliner_context_size;
+  int trace_context_size;
+
+  Printer()
+      : snippet(true), color_mode(ColorMode::automatic), address(false),
+        object(false), inliner_context_size(5), trace_context_size(7) {}
+
+  template <typename ST> FILE *print(ST &st, FILE *fp = stderr) {
+    cfile_streambuf obuf(fp);
+    std::ostream os(&obuf);
+    Colorize colorize(os);
+    colorize.activate(color_mode, fp);
+    print_stacktrace(st, os, colorize);
+    return fp;
+  }
+
+  template <typename ST> std::ostream &print(ST &st, std::ostream &os) {
+    Colorize colorize(os);
+    colorize.activate(color_mode);
+    print_stacktrace(st, os, colorize);
+    return os;
+  }
+
+  template <typename IT>
+  FILE *print(IT begin, IT end, FILE *fp = stderr, size_t thread_id = 0) {
+    cfile_streambuf obuf(fp);
+    std::ostream os(&obuf);
+    Colorize colorize(os);
+    colorize.activate(color_mode, fp);
+    print_stacktrace(begin, end, os, thread_id, colorize);
+    return fp;
+  }
+
+  template <typename IT>
+  std::ostream &print(IT begin, IT end, std::ostream &os,
+                      size_t thread_id = 0) {
+    Colorize colorize(os);
+    colorize.activate(color_mode);
+    print_stacktrace(begin, end, os, thread_id, colorize);
+    return os;
+  }
+
+  TraceResolver const &resolver() const { return _resolver; }
+
+private:
+  TraceResolver _resolver;
+  SnippetFactory _snippets;
+
+  template <typename ST>
+  void print_stacktrace(ST &st, std::ostream &os, Colorize &colorize) {
+    print_header(os, st.thread_id());
+    _resolver.load_stacktrace(st);
+    for (size_t trace_idx = st.size(); trace_idx > 0; --trace_idx) {
+      print_trace(os, _resolver.resolve(st[trace_idx - 1]), colorize);
+    }
+  }
+
+  template <typename IT>
+  void print_stacktrace(IT begin, IT end, std::ostream &os, size_t thread_id,
+                        Colorize &colorize) {
+    print_header(os, thread_id);
+    for (; begin != end; ++begin) {
+      print_trace(os, *begin, colorize);
+    }
+  }
+
+  void print_header(std::ostream &os, size_t thread_id) {
+    os << "Stack trace (most recent call last)";
+    if (thread_id) {
+      os << " in thread " << thread_id;
+    }
+    os << ":\n";
+  }
+
+  void print_trace(std::ostream &os, const ResolvedTrace &trace,
+                   Colorize &colorize) {
+    os << "#" << std::left << std::setw(2) << trace.idx << std::right;
+    bool already_indented = true;
+
+    if (!trace.source.filename.size() || object) {
+      os << "   Object \"" << trace.object_filename << "\", at " << trace.addr
+         << ", in " << trace.object_function << "\n";
+      already_indented = false;
+    }
+
+    for (size_t inliner_idx = trace.inliners.size(); inliner_idx > 0;
+         --inliner_idx) {
+      if (!already_indented) {
+        os << "   ";
+      }
+      const ResolvedTrace::SourceLoc &inliner_loc =
+          trace.inliners[inliner_idx - 1];
+      print_source_loc(os, " | ", inliner_loc);
+      if (snippet) {
+        print_snippet(os, "    | ", inliner_loc, colorize, Color::purple,
+                      inliner_context_size);
+      }
+      already_indented = false;
+    }
+
+    if (trace.source.filename.size()) {
+      if (!already_indented) {
+        os << "   ";
+      }
+      print_source_loc(os, "   ", trace.source, trace.addr);
+      if (snippet) {
+        print_snippet(os, "      ", trace.source, colorize, Color::yellow,
+                      trace_context_size);
+      }
+    }
+  }
+
+  void print_snippet(std::ostream &os, const char *indent,
+                     const ResolvedTrace::SourceLoc &source_loc,
+                     Colorize &colorize, Color::type color_code,
+                     int context_size) {
+    using namespace std;
+    typedef SnippetFactory::lines_t lines_t;
+
+    lines_t lines = _snippets.get_snippet(source_loc.filename, source_loc.line,
+                                          static_cast<unsigned>(context_size));
+
+    for (lines_t::const_iterator it = lines.begin(); it != lines.end(); ++it) {
+      if (it->first == source_loc.line) {
+        colorize.set_color(color_code);
+        os << indent << ">";
+      } else {
+        os << indent << " ";
+      }
+      os << std::setw(4) << it->first << ": " << it->second << "\n";
+      if (it->first == source_loc.line) {
+        colorize.set_color(Color::reset);
+      }
+    }
+  }
+
+  void print_source_loc(std::ostream &os, const char *indent,
+                        const ResolvedTrace::SourceLoc &source_loc,
+                        void *addr = nullptr) {
+    os << indent << "Source \"" << source_loc.filename << "\", line "
+       << source_loc.line << ", in " << source_loc.function;
+
+    if (address && addr != nullptr) {
+      os << " [" << addr << "]";
+    }
+    os << "\n";
+  }
+};
+
+/*************** SIGNALS HANDLING ***************/
+
+#if defined(BACKWARD_SYSTEM_LINUX) || defined(BACKWARD_SYSTEM_DARWIN)
+
+class SignalHandling {
+public:
+  static std::vector<int> make_default_signals() {
+    const int posix_signals[] = {
+      // Signals for which the default action is "Core".
+      SIGABRT, // Abort signal from abort(3)
+      SIGBUS,  // Bus error (bad memory access)
+      SIGFPE,  // Floating point exception
+      SIGILL,  // Illegal Instruction
+      SIGIOT,  // IOT trap. A synonym for SIGABRT
+      SIGQUIT, // Quit from keyboard
+      SIGSEGV, // Invalid memory reference
+      SIGSYS,  // Bad argument to routine (SVr4)
+      SIGTRAP, // Trace/breakpoint trap
+      SIGXCPU, // CPU time limit exceeded (4.2BSD)
+      SIGXFSZ, // File size limit exceeded (4.2BSD)
+#if defined(BACKWARD_SYSTEM_DARWIN)
+      SIGEMT, // emulation instruction executed
+#endif
+    };
+    return std::vector<int>(posix_signals,
+                            posix_signals +
+                                sizeof posix_signals / sizeof posix_signals[0]);
+  }
+
+  SignalHandling(const std::vector<int> &posix_signals = make_default_signals())
+      : _loaded(false) {
+    bool success = true;
+
+    const size_t stack_size = 1024 * 1024 * 8;
+    _stack_content.reset(static_cast<char *>(malloc(stack_size)));
+    if (_stack_content) {
+      stack_t ss;
+      ss.ss_sp = _stack_content.get();
+      ss.ss_size = stack_size;
+      ss.ss_flags = 0;
+      if (sigaltstack(&ss, nullptr) < 0) {
+        success = false;
+      }
+    } else {
+      success = false;
+    }
+
+    for (size_t i = 0; i < posix_signals.size(); ++i) {
+      struct sigaction action;
+      memset(&action, 0, sizeof action);
+      action.sa_flags =
+          static_cast<int>(SA_SIGINFO | SA_ONSTACK | SA_NODEFER | SA_RESETHAND);
+      sigfillset(&action.sa_mask);
+      sigdelset(&action.sa_mask, posix_signals[i]);
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdisabled-macro-expansion"
+#endif
+      action.sa_sigaction = &sig_handler;
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
+      int r = sigaction(posix_signals[i], &action, nullptr);
+      if (r < 0)
+        success = false;
+    }
+
+    _loaded = success;
+  }
+
+  bool loaded() const { return _loaded; }
+
+  static void handleSignal(int, siginfo_t *info, void *_ctx) {
+    ucontext_t *uctx = static_cast<ucontext_t *>(_ctx);
+
+    StackTrace st;
+    void *error_addr = nullptr;
+#ifdef REG_RIP // x86_64
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.gregs[REG_RIP]);
+#elif defined(REG_EIP) // x86_32
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.gregs[REG_EIP]);
+#elif defined(__arm__)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.arm_pc);
+#elif defined(__aarch64__)
+    #if defined(__APPLE__)
+      error_addr = reinterpret_cast<void *>(uctx->uc_mcontext->__ss.__pc);
+    #else
+      error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.pc);
+    #endif
+#elif defined(__loongarch__)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.__pc);
+#elif defined(__mips__)
+    error_addr = reinterpret_cast<void *>(
+        reinterpret_cast<struct sigcontext *>(&uctx->uc_mcontext)->sc_pc);
+#elif defined(__ppc__) || defined(__powerpc) || defined(__powerpc__) ||        \
+    defined(__POWERPC__)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.regs->nip);
+#elif defined(__riscv)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.__gregs[REG_PC]);
+#elif defined(__s390x__)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext.psw.addr);
+#elif defined(__APPLE__) && defined(__x86_64__)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext->__ss.__rip);
+#elif defined(__APPLE__)
+    error_addr = reinterpret_cast<void *>(uctx->uc_mcontext->__ss.__eip);
+#else
+#warning ":/ sorry, ain't know no nothing none not of your architecture!"
+#endif
+    if (error_addr) {
+      st.load_from(error_addr, 32, reinterpret_cast<void *>(uctx),
+                   info->si_addr);
+    } else {
+      st.load_here(32, reinterpret_cast<void *>(uctx), info->si_addr);
+    }
+
+    Printer printer;
+    printer.address = true;
+    printer.print(st, stderr);
+
+#if _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
+    psiginfo(info, nullptr);
+#else
+    (void)info;
+#endif
+  }
+
+private:
+  details::handle<char *> _stack_content;
+  bool _loaded;
+
+#ifdef __GNUC__
+  __attribute__((noreturn))
+#endif
+  static void
+  sig_handler(int signo, siginfo_t *info, void *_ctx) {
+    handleSignal(signo, info, _ctx);
+
+    // try to forward the signal.
+    raise(info->si_signo);
+
+    // terminate the process immediately.
+    puts("watf? exit");
+    _exit(EXIT_FAILURE);
+  }
+};
+
+#endif // BACKWARD_SYSTEM_LINUX || BACKWARD_SYSTEM_DARWIN
+
+#ifdef BACKWARD_SYSTEM_WINDOWS
+
+class SignalHandling {
+public:
+  SignalHandling(const std::vector<int> & = std::vector<int>())
+      : reporter_thread_([]() {
+          /* We handle crashes in a utility thread:
+            backward structures and some Windows functions called here
+            need stack space, which we do not have when we encounter a
+            stack overflow.
+            To support reporting stack traces during a stack overflow,
+            we create a utility thread at startup, which waits until a
+            crash happens or the program exits normally. */
+
+          {
+            std::unique_lock<std::mutex> lk(mtx());
+            cv().wait(lk, [] { return crashed() != crash_status::running; });
+          }
+          if (crashed() == crash_status::crashed) {
+            handle_stacktrace(skip_recs());
+          }
+          {
+            std::unique_lock<std::mutex> lk(mtx());
+            crashed() = crash_status::ending;
+          }
+          cv().notify_one();
+        }) {
+    SetUnhandledExceptionFilter(crash_handler);
+
+    signal(SIGABRT, signal_handler);
+    _set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
+
+    std::set_terminate(&terminator);
+#ifndef BACKWARD_ATLEAST_CXX17
+    std::set_unexpected(&terminator);
+#endif
+    _set_purecall_handler(&terminator);
+    _set_invalid_parameter_handler(&invalid_parameter_handler);
+  }
+  bool loaded() const { return true; }
+
+  ~SignalHandling() {
+    {
+      std::unique_lock<std::mutex> lk(mtx());
+      crashed() = crash_status::normal_exit;
+    }
+
+    cv().notify_one();
+
+    reporter_thread_.join();
+  }
+
+private:
+  static CONTEXT *ctx() {
+    static CONTEXT data;
+    return &data;
+  }
+
+  enum class crash_status { running, crashed, normal_exit, ending };
+
+  static crash_status &crashed() {
+    static crash_status data;
+    return data;
+  }
+
+  static std::mutex &mtx() {
+    static std::mutex data;
+    return data;
+  }
+
+  static std::condition_variable &cv() {
+    static std::condition_variable data;
+    return data;
+  }
+
+  static HANDLE &thread_handle() {
+    static HANDLE handle;
+    return handle;
+  }
+
+  std::thread reporter_thread_;
+
+  // TODO: how not to hardcode these?
+  static const constexpr int signal_skip_recs =
+#ifdef __clang__
+      // With clang, RtlCaptureContext also captures the stack frame of the
+      // current function Below that, there ar 3 internal Windows functions
+      4
+#else
+      // With MSVC cl, RtlCaptureContext misses the stack frame of the current
+      // function The first entries during StackWalk are the 3 internal Windows
+      // functions
+      3
+#endif
+      ;
+
+  static int &skip_recs() {
+    static int data;
+    return data;
+  }
+
+  static inline void terminator() {
+    crash_handler(signal_skip_recs);
+    abort();
+  }
+
+  static inline void signal_handler(int) {
+    crash_handler(signal_skip_recs);
+    abort();
+  }
+
+  static inline void __cdecl invalid_parameter_handler(const wchar_t *,
+                                                       const wchar_t *,
+                                                       const wchar_t *,
+                                                       unsigned int,
+                                                       uintptr_t) {
+    crash_handler(signal_skip_recs);
+    abort();
+  }
+
+  NOINLINE static LONG WINAPI crash_handler(EXCEPTION_POINTERS *info) {
+    // The exception info supplies a trace from exactly where the issue was,
+    // no need to skip records
+    crash_handler(0, info->ContextRecord);
+    return EXCEPTION_CONTINUE_SEARCH;
+  }
+
+  NOINLINE static void crash_handler(int skip, CONTEXT *ct = nullptr) {
+
+    if (ct == nullptr) {
+      RtlCaptureContext(ctx());
+    } else {
+      memcpy(ctx(), ct, sizeof(CONTEXT));
+    }
+    DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
+                    GetCurrentProcess(), &thread_handle(), 0, FALSE,
+                    DUPLICATE_SAME_ACCESS);
+
+    skip_recs() = skip;
+
+    {
+      std::unique_lock<std::mutex> lk(mtx());
+      crashed() = crash_status::crashed;
+    }
+
+    cv().notify_one();
+
+    {
+      std::unique_lock<std::mutex> lk(mtx());
+      cv().wait(lk, [] { return crashed() != crash_status::crashed; });
+    }
+  }
+
+  static void handle_stacktrace(int skip_frames = 0) {
+    // printer creates the TraceResolver, which can supply us a machine type
+    // for stack walking. Without this, StackTrace can only guess using some
+    // macros.
+    // StackTrace also requires that the PDBs are already loaded, which is done
+    // in the constructor of TraceResolver
+    Printer printer;
+
+    StackTrace st;
+    st.set_machine_type(printer.resolver().machine_type());
+    st.set_thread_handle(thread_handle());
+    st.load_here(32 + skip_frames, ctx());
+    st.skip_n_firsts(skip_frames);
+
+    printer.address = true;
+    printer.print(st, std::cerr);
+  }
+};
+
+#endif // BACKWARD_SYSTEM_WINDOWS
+
+#ifdef BACKWARD_SYSTEM_UNKNOWN
+
+class SignalHandling {
+public:
+  SignalHandling(const std::vector<int> & = std::vector<int>()) {}
+  bool init() { return false; }
+  bool loaded() { return false; }
+};
+
+#endif // BACKWARD_SYSTEM_UNKNOWN
+
+} // namespace backward
+
+#endif /* H_GUARD */