Program Listing for File 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
#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)
// - 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]);
++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, ¤t_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, ¤t_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, ¤t_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, ¤t_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();
FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(char*)&lpMsgBuf, 0, NULL);
printf(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(__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 */