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/System/ThreadLocal.h"
  19 #include "llvm/ADT/SmallString.h"
  20 using namespace llvm;
  21
  22 namespace llvm {
  23   bool DisablePrettyStackTrace = false;
  24 }
  25
  26 // FIXME: This should be thread local when llvm supports threads.
  27 static sys::ThreadLocal<const PrettyStackTraceEntry> PrettyStackTraceHead;
  28
  29 static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
  30   unsigned NextID = 0;
  31   if (Entry->getNextEntry())
  32     NextID = PrintStack(Entry->getNextEntry(), OS);
  33   OS << NextID << ".\t";
  34   Entry->print(OS);
  35
  36   return NextID+1;
  37 }
  38
  39 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
  40 static void PrintCurStackTrace(raw_ostream &OS) {
  41   // Don't print an empty trace.
  42   if (PrettyStackTraceHead.get() == 0) return;
  43
  44   // If there are pretty stack frames registered, walk and emit them.
  45   OS << "Stack dump:\n";
  46
  47   PrintStack(PrettyStackTraceHead.get(), OS);
  48   OS.flush();
  49 }
  50
  51 // Integrate with crash reporter.
  52 #ifdef __APPLE__
  53 extern "C" const char *__crashreporter_info__;
  54 const char *__crashreporter_info__ = 0;
  55 #endif
  56
  57
  58 /// CrashHandler - This callback is run if a fatal signal is delivered to the
  59 /// process, it prints the pretty stack trace.
  60 static void CrashHandler(void *Cookie) {
  61 #ifndef __APPLE__
  62   // On non-apple systems, just emit the crash stack trace to stderr.
  63   PrintCurStackTrace(errs());
  64 #else
  65   // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
  66   // put it into __crashreporter_info__.
  67   SmallString<2048> TmpStr;
  68   {
  69     raw_svector_ostream Stream(TmpStr);
  70     PrintCurStackTrace(Stream);
  71   }
  72
  73   if (!TmpStr.empty()) {
  74     __crashreporter_info__ = strdup(TmpStr.c_str());
  75     errs() << __crashreporter_info__;
  76   }
  77
  78 #endif
  79 }
  80
  81 static bool RegisterCrashPrinter() {
  82   if (!DisablePrettyStackTrace)
  83     sys::AddSignalHandler(CrashHandler, 0);
  84   return false;
  85 }
  86
  87 PrettyStackTraceEntry::PrettyStackTraceEntry() {
  88   // The first time this is called, we register the crash printer.
  89   static bool HandlerRegistered = RegisterCrashPrinter();
  90   HandlerRegistered = HandlerRegistered;
  91
  92   // Link ourselves.
  93   NextEntry = PrettyStackTraceHead.get();
  94   PrettyStackTraceHead.set(this);
  95 }
  96
  97 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
  98   assert(PrettyStackTraceHead.get() == this &&
  99          "Pretty stack trace entry destruction is out of order");
 100   PrettyStackTraceHead.set(getNextEntry());
 101 }
 102
 103 void PrettyStackTraceString::print(raw_ostream &OS) const {
 104   OS << Str << "\n";
 105 }
 106
 107 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
 108   OS << "Program arguments: ";
 109   // Print the argument list.
 110   for (unsigned i = 0, e = ArgC; i != e; ++i)
 111     OS << ArgV[i] << ' ';
 112   OS << '\n';
 113 }
 114