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backward.hpp
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backward.hpp
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/*
* 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
#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>
#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)
// - variables name and values (if not optimized out)
// - 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)
// - variables name and values (if not optimized out)
// - 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
#include <signal.h>
#include <sys/stat.h>
#include <syscall.h>
#include <unistd.h>
#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>
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#include <dlfcn.h>
#undef _GNU_SOURCE
#else
#include <dlfcn.h>
#endif
#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>
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#include <dlfcn.h>
#undef _GNU_SOURCE
#else
#include <dlfcn.h>
#endif
#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;
#define NOMINMAX
#include <windows.h>
#include <winnt.h>
#include <psapi.h>
#include <signal.h>
#ifndef __clang__
#undef NOINLINE
#define NOINLINE __declspec(noinline)
#endif
#pragma comment(lib, "psapi.lib")
#pragma comment(lib, "dbghelp.lib")
// 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
#include <unwind.h>
// 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]);