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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
# 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_UNKNOWN
// - placebo implementation, does nothing.
//
# if defined(BACKWARD_SYSTEM_LINUX)
# elif defined(BACKWARD_SYSTEM_DARWIN)
# elif defined(BACKWARD_SYSTEM_UNKNOWN)
# else
# if defined(__linux) || defined(__linux__)
# define BACKWARD_SYSTEM_LINUX
# elif defined(__APPLE__)
# define BACKWARD_SYSTEM_DARWIN
# else
# define BACKWARD_SYSTEM_UNKNOWN
# endif
# endif
# include <algorithm>
# include <cctype>
# include <cstdio>
# include <cstdlib>
# include <cstring>
# include <fstream>
# include <iomanip>
# include <iostream>
# include <new>
# include <sstream>
# include <streambuf>
# include <string>
# include <vector>
# include <limits>
# 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_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_BACKTRACE == 1
# else
# undef BACKWARD_HAS_UNWIND
# define BACKWARD_HAS_UNWIND 1
# 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 <sys/stat.h>
# include <syscall.h>
# include <unistd.h>
# include <signal.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 <elfutils/libdw.h>
# include <elfutils/libdwfl.h>
# include <dwarf.h>
# endif
# if BACKWARD_HAS_DWARF == 1
# include <libelf.h>
# include <dwarf.h>
# include <libdwarf.h>
# include <map>
# include <algorithm>
# 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_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
# else
# undef BACKWARD_HAS_UNWIND
# define BACKWARD_HAS_UNWIND 1
# undef BACKWARD_HAS_BACKTRACE
# define BACKWARD_HAS_BACKTRACE 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 <sys/stat.h>
# include <unistd.h>
# include <signal.h>
# if (BACKWARD_HAS_BACKTRACE == 1) || (BACKWARD_HAS_BACKTRACE_SYMBOL == 1)
# include <execinfo.h>
# endif
# endif // defined(BACKWARD_SYSTEM_DARWIN)
# 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
# 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 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 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_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
# 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);
}
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.release(), &_demangle_buffer_length, nullptr);
if (result) {
_demangle_buffer.reset(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> {
};
} // 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) { return Trace(); }
size_t load_here(size_t = 0) { return 0; }
size_t load_from(void*, size_t = 0) { return 0; }
size_t thread_id() const { return 0; }
void skip_n_firsts(size_t) {}
};
class StackTraceImplBase {
public:
StackTraceImplBase() : _thread_id(0), _skip(0) {}
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
}
size_t skip_n_firsts() const { return _skip; }
private:
size_t _thread_id;
size_t _skip;
};
class StackTraceImplHolder : public StackTraceImplBase {
public:
size_t size() const { return _stacktrace.size() ? _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:
__attribute__((noinline)) // TODO use some macro
size_t
load_here(size_t depth = 32)
{
load_thread_info();
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)
{
load_here(depth + 8);
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; }
};
};
# else // BACKWARD_HAS_UNWIND == 0
template <>
class StackTraceImpl<system_tag::current_tag> : public StackTraceImplHolder {
public:
__attribute__((noinline)) // TODO use some macro
size_t
load_here(size_t depth = 32)
{
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)
{
load_here(depth + 8);
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();
}
};
# endif // BACKWARD_HAS_UNWIND
class StackTrace : public StackTraceImpl<system_tag::current_tag> {
};
/*************** TRACE RESOLVER ***************/
template <typename TAG>
class TraceResolverImpl;
# ifdef BACKWARD_SYSTEM_UNKNOWN
template <>
class TraceResolverImpl<system_tag::unknown_tag> {
public:
template <class ST>
void load_stacktrace(ST&)
{
}
ResolvedTrace resolve(ResolvedTrace t) { return t; }
};
# endif
class TraceResolverImplBase {
protected:
std::string demangle(const char* funcname) { return _demangler.demangle(funcname); }
private:
details::demangler _demangler;
};
# ifdef BACKWARD_SYSTEM_LINUX
template <typename STACKTRACE_TAG>
class TraceResolverLinuxImpl;
# if BACKWARD_HAS_BACKTRACE_SYMBOL == 1
template <>
class TraceResolverLinuxImpl<trace_resolver_tag::backtrace_symbol> : public TraceResolverImplBase {
public:
template <class ST>
void load_stacktrace(ST& st)
{
using namespace details;
if (st.size() == 0) {
return;
}
_symbols.reset(backtrace_symbols(st.begin(), (int)st.size()));
}
ResolvedTrace resolve(ResolvedTrace trace)
{
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 TraceResolverImplBase {
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;
}
public:
TraceResolverLinuxImpl() : _bfd_loaded(false) {}
template <class ST>
void load_stacktrace(ST&)
{
}
ResolvedTrace resolve(ResolvedTrace trace)
{
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...
}
std::string argv0;
{
std::ifstream ifs("/proc/self/cmdline");
std::getline(ifs, argv0, '\0');
}
std::string tmp;
if (symbol_info.dli_fname == argv0) {
tmp = read_symlink("/proc/self/exe");
symbol_info.dli_fname = tmp.c_str();
}
// 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 = symbol_info.dli_fname;
bfd_fileobject& fobj = load_object_with_bfd(symbol_info.dli_fname);
if (!fobj.handle) {
return trace; // sad, we couldn't load the object :(
}
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;
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