backtrace: give consistent outputs for backtrace

backtrace.hpp

@@ -3,33 +3,27 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
  */
 
-#ifndef __UTIL_BACKTRACE_HPP
+#pragma once
-#define __UTIL_BACKTRACE_HPP
 
-#include <string>
 #include <vector>
 #include <iosfwd>
 
 
-//-----------------------------------------------------------------------------
+///////////////////////////////////////////////////////////////////////////////
-namespace debug {
+namespace cruft {
     class backtrace {
-    protected:
-        static const unsigned int DEFAULT_DEPTH = 16;
-        std::vector<void *>       m_frames;
-
     public:
         backtrace (void);
 
         const auto& frames(void) const { return m_frames; }
+
+    private:
+        std::vector<void *> m_frames;
     };
 
     std::ostream&
-    operator<< (std::ostream&, const debug::backtrace&);
+    operator<< (std::ostream&, backtrace const&);
 }
-
-
-#endif

backtrace_execinfo.cpp

@@ -3,47 +3,53 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
  */
 
-
 #include "backtrace.hpp"
 
-#include "debug/assert.hpp"
-#include "exe.hpp"
-#include "io.hpp"
 #include "cast.hpp"
+#include "iterator/zip.hpp"
 
-#include <sstream>
+#include <ostream>
-#include <cstdio>
-#include <cstdlib>
-#include <execinfo.h>
 #include <memory>
 
+#include <execinfo.h>
+
+using cruft::backtrace;
+
+static constexpr std::size_t DEFAULT_DEPTH = 16;
+
 
 ///////////////////////////////////////////////////////////////////////////////
-debug::backtrace::backtrace (void):
+backtrace::backtrace (void)
-    m_frames (DEFAULT_DEPTH)
+    : m_frames (DEFAULT_DEPTH)
 {
-    size_t last;
+    do {
-    size_t size = m_frames.size ();
+        int const target = static_cast<int> (m_frames.size ());
+        int const last = ::backtrace (
+            m_frames.data (), target
+        );
 
-    while ((last = ::backtrace (&m_frames[0], cruft::cast::lossless <int> (m_frames.size ()))) == size)
+        if (last < target) {
-        m_frames.resize (size = m_frames.size () * 2);
-
-    CHECK_GT (last, 0u);
             m_frames.resize (last);
+            break;
+        }
+
+        m_frames.resize (m_frames.size () * 2);
+    } while (1);
 }
 
 
 ///////////////////////////////////////////////////////////////////////////////
 std::ostream&
-debug::operator <<(std::ostream &os, const debug::backtrace &rhs) {
+cruft::operator <<(std::ostream &os, backtrace const &rhs) {
+    os << "[ ";
+
     auto const &frames = rhs.frames ();
 
-    // We don't use the array form of unique_ptr as clang fails on ambigious constructors
+    using strings_t = std::unique_ptr<char *, decltype(&std::free)>;
-    using str_t = std::unique_ptr<char *, decltype(&std::free)>;
+    strings_t const names (
-    str_t names (
         backtrace_symbols (
             frames.data (),
             cruft::cast::lossless <int> (frames.size ())
@@ -51,8 +57,12 @@ debug::operator <<(std::ostream &os, const debug::backtrace &rhs) {
         ::free
     );
 
-    for (unsigned int i = 0; i < frames.size (); ++i)
+    for (auto const [idx,addr]: cruft::iterator::izip (frames)) {
-        os << frames[i] << '\t' << names.get()[i] << '\n';
+        os << "{ addr: "  << frames[idx]
+           << ", name: '" << names.get()[idx] << '\''
+           << " }, ";
+    }
 
+    os << " ]";
     return os;
 }

backtrace_stackwalk.cpp

@@ -14,12 +14,12 @@
 
 // windows.h needs to be included here so that it defines some symbols that
 // dbghelp.h requires.
-#include <windows.h>
+#include "win32/windows.hpp"
 #include <dbghelp.h>
 
 #include <ostream>
 
-using debug::backtrace;
+using cruft::backtrace;
 
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -78,27 +78,34 @@ backtrace::backtrace ()
 
 ///////////////////////////////////////////////////////////////////////////////
 std::ostream&
-debug::operator<< (std::ostream &os, const debug::backtrace &b)
+cruft::operator<< (std::ostream &os, backtrace const &obj)
 {
-    const auto self = GetCurrentProcess ();
+    const auto process = GetCurrentProcess ();
 
     struct {
-        IMAGEHLP_SYMBOL64 info;
+        SYMBOL_INFO info;
         char name[255];
-    } sym;
+        char null = '\0';
+    } sym {};
 
     sym.info.SizeOfStruct = sizeof (sym.info);
-    sym.info.MaxNameLength = std::size (sym.name);
+    sym.info.MaxNameLen = std::size (sym.name);
+
+    os << "[ ";
+
+    for (auto const frame: obj.frames ()) {
+        os << "{ addr: " << frame << ", name: ";
 
-    for (auto frame: b.frames ()) {
         // Find the symbol name
         sym.info.Name[0] = '\0';
         memset (sym.name, 0, sizeof (sym.name));
-        SymGetSymFromAddr64 (self, reinterpret_cast<uintptr_t> (frame), nullptr, &sym.info);
+        if (FALSE == SymFromAddr (process, reinterpret_cast<uintptr_t> (frame), nullptr, &sym.info)) {
-        *std::rbegin (sym.name) = '\0';
+            os << "null }, ";
-
+        } else {
-        os << self << '\t' << frame << '\t' << sym.info.Name << '\n';
+            os << '\'' << sym.info.Name << "' }, ";
+        }
     }
 
+    os << " ]";
     return os;
 }

backtrace_win32.cpp

@@ -4,7 +4,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * Copyright:
- *      2012-2016, Danny Robson <danny@nerdcruft.net>
+ *      2012-2019, Danny Robson <danny@nerdcruft.net>
  */
 
 #include "backtrace.hpp"
@@ -18,9 +18,13 @@
 #include <cstdlib>
 #include <dbghelp.h>
 
+using cruft::backtrace;
+
+static constexpr std::size_t DEFAULT_DEPTH = 16;
+
 
 ///////////////////////////////////////////////////////////////////////////////
-debug::backtrace::backtrace (void)
+backtrace::backtrace (void)
 {
     m_frames.resize (DEFAULT_DEPTH);
 
@@ -29,8 +33,8 @@ debug::backtrace::backtrace (void)
         cruft::win32::error::throw_code ();
 
     while (true) {
-        auto res = CaptureStackBackTrace (1, m_frames.size (), m_frames.data (), NULL);
+        auto const res = CaptureStackBackTrace (1, m_frames.size (), m_frames.data (), NULL);
-        if (res != m_frames.size ()) {
+        if (res < m_frames.size ()) {
             m_frames.resize (res);
             break;
         }
@@ -42,9 +46,8 @@ debug::backtrace::backtrace (void)
 
 ///////////////////////////////////////////////////////////////////////////////
 std::ostream&
-debug::operator <<(std::ostream &os, const debug::backtrace &rhs) {
+debug::operator <<(std::ostream &os, ::cruft::backtrace const &rhs) {
-    static auto self  = GetCurrentProcess ();
+    static auto process = GetCurrentProcess ();
-    static auto ready = SymInitialize (self, nullptr, TRUE);
     CHECK (ready);
 
     static constexpr size_t MAX_LENGTH = 255;
@@ -56,13 +59,17 @@ debug::operator <<(std::ostream &os, const debug::backtrace &rhs) {
     symbol.info.MaxNameLen   = MAX_LENGTH;
     symbol.info.SizeOfStruct = sizeof (SYMBOL_INFO);
 
+    os << "[ ";
     for (void *frame: rhs.frames ()) {
         symbol.name[0] = '\0';
-        SymFromAddr (self, (DWORD64)frame, 0, &symbol.info);
+        SymFromAddr (process, (DWORD64)frame, 0, &symbol.info);
         symbol.name[MAX_LENGTH] = '\0';
 
-        os << self << "\t" << frame << "\t" << symbol.name << "\n";
+        os << "{ addr: "  << frame
+           << ", name: '" << symbol.name '\''
+           << " }, ";
     }
 
+    os << " ]";
     return os;
 }

debug/assert.cpp

@@ -18,7 +18,7 @@
 void
 cruft::debug::detail::panic (const char *msg)
 {
-    std::cerr << "PANIC: " << msg << "\n" << ::debug::backtrace () << std::endl;
+    std::cerr << "PANIC: " << msg << "\n" << ::cruft::backtrace () << std::endl;
     breakpoint ();
     abort ();
 }

debug/system.cpp

@@ -33,12 +33,12 @@ static void abort_with_trace (void)
         try {
             std::rethrow_exception (ptr);
         } catch (std::exception const &x) {
-            LOG_EMERGENCY ("unhandled exception: %!\n%!", x.what (), debug::backtrace {});
+            LOG_EMERGENCY ("unhandled exception: %!\n%!", x.what (), ::cruft::backtrace {});
         } catch (...) {
-            LOG_EMERGENCY ("unhandled exception: %!\n", debug::backtrace {});
+            LOG_EMERGENCY ("unhandled exception: %!\n", ::cruft::backtrace {});
         }
     } else {
-        LOG_EMERGENCY ("aborting: %!", debug::backtrace {});
+        LOG_EMERGENCY ("aborting: %!", ::cruft::backtrace {});
     }
 
     std::abort ();

test/backtrace.cpp

@@ -11,7 +11,7 @@ main (int, char **) {
     cruft::TAP::logger tap;
 
     // Instantiate a backtrace just so we know that linking has worked.
-    debug::backtrace foo;
+    ::cruft::backtrace foo;
     (void)foo;
 
     tap.noop ();