maia::debug Namespace Reference

Classes
struct	Tracer

Functions
void	backtrace ()
	Prints a backtrace of the function call path if possible. More...
void	backtrace_gcc (const MString &fileName, const MInt noFramesOmitted=1)
	Prints a backtrace of the function call path if possible. More...
void	backtrace_gcc (const MString &NotUsed(fileName), MInt NotUsed(noFramesOmitted))

Function Documentation

backtrace()

void maia::debug::backtrace ( )

inline

Author

Fabian Klemp f.kle.nosp@m.mp@a.nosp@m.ia.rw.nosp@m.th-a.nosp@m.achen.nosp@m..de

Date

2015-09-16

Uses the LLVMSupport library to print a stacktrace Note: use BACKTRACE(...) instead of calling this method directly

Definition at line 58 of file backtrace.h.

                        {
  llvm::errs() << "Backtrace (line numbers may be too large by 1-3 lines):\n";
  llvm::sys::PrintStackTrace(llvm::errs());
}

backtrace_gcc() [1/2]

void maia::debug::backtrace_gcc ( const MString &  fileName, const MInt  noFramesOmitted = 1  )

inline

Author

Michael Schlottke (mic) mic@a.nosp@m.ia.r.nosp@m.wth-a.nosp@m.ache.nosp@m.n.de

Date

2013-10-09

Parameters

[in]

noFramesOmitted

Set number of omitted frames (e.g. to hide backtrace() itself).

Works only with GCC. Needs command line tool 'addr2line' to be callable from within MAIA.

Definition at line 77 of file backtrace.h.

                                                                                   {
  // Get trace
  const int maxNoTraces = 128;
  void* trace[maxNoTraces];
  int noTraces = ::backtrace(trace, maxNoTraces);
 
  // Get messages (i.e. function names)
  char** messages = backtrace_symbols(trace, noTraces);
 
  // Create stream and char buffer for single-flush printing
  std::stringstream s;
  const MInt maxLineLength = 1024;
  MChar line[maxLineLength];
 
  // Print out messages one by one
  const MInt maxCmdSize = 1024;
  MInt frameId = 0;
  const MInt noFrames = noTraces - noFramesOmitted;
  const MInt width = noFrames ? floor(log10(noFrames)) + 1 : 1;
  s << "\nBacktrace (line numbers are usually too large, typically by 1-3 "
       "lines):\n";
  for(MInt i = noFramesOmitted; i < noTraces; i++) {
    // Get demangled function name
    MString mangled(messages[i]);
    mangled = mangled.substr(mangled.find("(") + 1);
    mangled = mangled.substr(0, mangled.find("+"));
    int status;
    char* demangledChar = abi::__cxa_demangle(mangled.c_str(), 0, 0, &status);
 
    // Only use demangled name if demangling worked
    const MString demangled = (status == 0) ? demangledChar : messages[i];
    free(demangledChar);
 
    // Get filename/line number using addr2line
    char cmd[maxCmdSize];
    std::sprintf(cmd, "addr2line %p -s -e %s", trace[i], fileName.c_str());
    MString fileline;
    FILE* pipe = popen(cmd, "r");
    if(!pipe) {
      fileline = "n/a";
    } else {
      char buffer[128];
      while(!feof(pipe)) {
        if(fgets(buffer, 128, pipe) != nullptr) {
          fileline += buffer;
        }
      }
    }
    pclose(pipe);
 
    // Parse output of addr2line to skip newline and possible discriminator
    // information
    fileline = fileline.substr(0, fileline.length() - 1);
    fileline = fileline.substr(0, fileline.find(" "));
 
    // Print function names + filename:lineno
    std::sprintf(line, "#%-*d 0x%016lx in %s at %s\n", width, frameId++, reinterpret_cast<uintptr_t>(trace[i]),
                 demangled.c_str(), fileline.c_str());
    line[maxLineLength - 1] = '\0';
    s << line;
  }
  std::cout << s.str() << std::endl;
}

backtrace_gcc() [2/2]

void maia::debug::backtrace_gcc ( const MString &  NotUsedfileName, MInt   NotUsednoFramesOmitted  )

inline

Definition at line 141 of file backtrace.h.

                                                                                           {
  std::cout << "Not using GCC - backtrace disabled." << std::endl;
}