lib/Support/PrettyStackTrace.cpp

   1 //===- PrettyStackTrace.cpp - Pretty Crash Handling -----------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines some helpful functions for dealing with the possibility of
  11 // Unix signals occuring while your program is running.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Support/PrettyStackTrace.h"
  16 #include "llvm/Support/raw_ostream.h"
  17 #include "llvm/System/Signals.h"
  18 #include "llvm/ADT/SmallString.h"
  19 using namespace llvm;
  20
  21 // FIXME: This should be thread local when llvm supports threads.
  22 static const PrettyStackTraceEntry *PrettyStackTraceHead = 0;
  23
  24 static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
  25   unsigned NextID = 0;
  26   if (Entry->getNextEntry())
  27     NextID = PrintStack(Entry->getNextEntry(), OS);
  28   OS << NextID << ".\t";
  29   Entry->print(OS);
  30
  31   return NextID+1;
  32 }
  33
  34 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
  35 static void PrintCurStackTrace(raw_ostream &OS) {
  36   // Don't print an empty trace.
  37   if (PrettyStackTraceHead == 0) return;
  38
  39   // If there are pretty stack frames registered, walk and emit them.
  40   OS << "Stack dump:\n";
  41
  42   PrintStack(PrettyStackTraceHead, OS);
  43   OS.flush();
  44 }
  45
  46 // Integrate with crash reporter.
  47 #ifdef __APPLE__
  48 extern "C" const char *__crashreporter_info__;
  49 const char *__crashreporter_info__ = 0;
  50 #endif
  51
  52
  53 /// CrashHandler - This callback is run if a fatal signal is delivered to the
  54 /// process, it prints the pretty stack trace.
  55 static void CrashHandler(void *Cookie) {
  56 #ifndef __APPLE__
  57   // On non-apple systems, just emit the crash stack trace to stderr.
  58   PrintCurStackTrace(errs());
  59 #else
  60   // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
  61   // put it into __crashreporter_info__.
  62   SmallString<2048> TmpStr;
  63   {
  64     raw_svector_ostream Stream(TmpStr);
  65     PrintCurStackTrace(Stream);
  66   }
  67
  68   if (!TmpStr.empty()) {
  69     __crashreporter_info__ = strdup(TmpStr.c_str());
  70     errs() << __crashreporter_info__;
  71   }
  72
  73 #endif
  74 }
  75
  76 static bool RegisterCrashPrinter() {
  77   sys::AddSignalHandler(CrashHandler, 0);
  78   return false;
  79 }
  80
  81 PrettyStackTraceEntry::PrettyStackTraceEntry() {
  82   // The first time this is called, we register the crash printer.
  83   static bool HandlerRegistered = RegisterCrashPrinter();
  84   HandlerRegistered = HandlerRegistered;
  85
  86   // Link ourselves.
  87   NextEntry = PrettyStackTraceHead;
  88   PrettyStackTraceHead = this;
  89 }
  90
  91 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
  92   assert(PrettyStackTraceHead == this &&
  93          "Pretty stack trace entry destruction is out of order");
  94   PrettyStackTraceHead = getNextEntry();
  95 }
  96
  97 void PrettyStackTraceString::print(raw_ostream &OS) const {
  98   OS << Str << "\n";
  99 }
 100
 101 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
 102   OS << "Program arguments: ";
 103   // Print the argument list.
 104   for (unsigned i = 0, e = ArgC; i != e; ++i)
 105     OS << ArgV[i] << ' ';
 106   OS << '\n';
 107 }
 108