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      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 occurring while your program is running.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm/Config/config.h"     // Get autoconf configuration settings
     16 #include "llvm/Support/PrettyStackTrace.h"
     17 #include "llvm/Support/raw_ostream.h"
     18 #include "llvm/Support/Signals.h"
     19 #include "llvm/Support/ThreadLocal.h"
     20 #include "llvm/ADT/SmallString.h"
     21 
     22 #ifdef HAVE_CRASHREPORTERCLIENT_H
     23 #include <CrashReporterClient.h>
     24 #endif
     25 
     26 using namespace llvm;
     27 
     28 namespace llvm {
     29   bool DisablePrettyStackTrace = false;
     30 }
     31 
     32 // FIXME: This should be thread local when llvm supports threads.
     33 static sys::ThreadLocal<const PrettyStackTraceEntry> PrettyStackTraceHead;
     34 
     35 static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
     36   unsigned NextID = 0;
     37   if (Entry->getNextEntry())
     38     NextID = PrintStack(Entry->getNextEntry(), OS);
     39   OS << NextID << ".\t";
     40   Entry->print(OS);
     41 
     42   return NextID+1;
     43 }
     44 
     45 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
     46 static void PrintCurStackTrace(raw_ostream &OS) {
     47   // Don't print an empty trace.
     48   if (PrettyStackTraceHead.get() == 0) return;
     49 
     50   // If there are pretty stack frames registered, walk and emit them.
     51   OS << "Stack dump:\n";
     52 
     53   PrintStack(PrettyStackTraceHead.get(), OS);
     54   OS.flush();
     55 }
     56 
     57 // Integrate with crash reporter libraries.
     58 #if defined (__APPLE__) && HAVE_CRASHREPORTERCLIENT_H
     59 //  If any clients of llvm try to link to libCrashReporterClient.a themselves,
     60 //  only one crash info struct will be used.
     61 extern "C" {
     62 CRASH_REPORTER_CLIENT_HIDDEN
     63 struct crashreporter_annotations_t gCRAnnotations
     64         __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION)))
     65         = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0 };
     66 }
     67 #elif defined (__APPLE__) && HAVE_CRASHREPORTER_INFO
     68 static const char *__crashreporter_info__ = 0;
     69 asm(".desc ___crashreporter_info__, 0x10");
     70 #endif
     71 
     72 
     73 /// CrashHandler - This callback is run if a fatal signal is delivered to the
     74 /// process, it prints the pretty stack trace.
     75 static void CrashHandler(void *) {
     76 #ifndef __APPLE__
     77   // On non-apple systems, just emit the crash stack trace to stderr.
     78   PrintCurStackTrace(errs());
     79 #else
     80   // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
     81   // put it into __crashreporter_info__.
     82   SmallString<2048> TmpStr;
     83   {
     84     raw_svector_ostream Stream(TmpStr);
     85     PrintCurStackTrace(Stream);
     86   }
     87 
     88   if (!TmpStr.empty()) {
     89 #ifdef HAVE_CRASHREPORTERCLIENT_H
     90     // Cast to void to avoid warning.
     91     (void)CRSetCrashLogMessage(std::string(TmpStr.str()).c_str());
     92 #elif HAVE_CRASHREPORTER_INFO
     93     __crashreporter_info__ = strdup(std::string(TmpStr.str()).c_str());
     94 #endif
     95     errs() << TmpStr.str();
     96   }
     97 
     98 #endif
     99 }
    100 
    101 static bool RegisterCrashPrinter() {
    102   if (!DisablePrettyStackTrace)
    103     sys::AddSignalHandler(CrashHandler, 0);
    104   return false;
    105 }
    106 
    107 PrettyStackTraceEntry::PrettyStackTraceEntry() {
    108   // The first time this is called, we register the crash printer.
    109   static bool HandlerRegistered = RegisterCrashPrinter();
    110   (void)HandlerRegistered;
    111 
    112   // Link ourselves.
    113   NextEntry = PrettyStackTraceHead.get();
    114   PrettyStackTraceHead.set(this);
    115 }
    116 
    117 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
    118   assert(PrettyStackTraceHead.get() == this &&
    119          "Pretty stack trace entry destruction is out of order");
    120   PrettyStackTraceHead.set(getNextEntry());
    121 }
    122 
    123 void PrettyStackTraceString::print(raw_ostream &OS) const {
    124   OS << Str << "\n";
    125 }
    126 
    127 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
    128   OS << "Program arguments: ";
    129   // Print the argument list.
    130   for (unsigned i = 0, e = ArgC; i != e; ++i)
    131     OS << ArgV[i] << ' ';
    132   OS << '\n';
    133 }
    134