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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/Support/PrettyStackTrace.h"
     16 #include "llvm-c/Core.h"
     17 #include "llvm/ADT/SmallString.h"
     18 #include "llvm/Config/config.h"     // Get autoconf configuration settings
     19 #include "llvm/Support/ManagedStatic.h"
     20 #include "llvm/Support/Signals.h"
     21 #include "llvm/Support/ThreadLocal.h"
     22 #include "llvm/Support/Watchdog.h"
     23 #include "llvm/Support/raw_ostream.h"
     24 
     25 #ifdef HAVE_CRASHREPORTERCLIENT_H
     26 #include <CrashReporterClient.h>
     27 #endif
     28 
     29 using namespace llvm;
     30 
     31 static ManagedStatic<sys::ThreadLocal<const PrettyStackTraceEntry> > PrettyStackTraceHead;
     32 
     33 static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
     34   unsigned NextID = 0;
     35   if (Entry->getNextEntry())
     36     NextID = PrintStack(Entry->getNextEntry(), OS);
     37   OS << NextID << ".\t";
     38   {
     39     sys::Watchdog W(5);
     40     Entry->print(OS);
     41   }
     42 
     43   return NextID+1;
     44 }
     45 
     46 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
     47 static void PrintCurStackTrace(raw_ostream &OS) {
     48   // Don't print an empty trace.
     49   if (!PrettyStackTraceHead->get()) return;
     50 
     51   // If there are pretty stack frames registered, walk and emit them.
     52   OS << "Stack dump:\n";
     53 
     54   PrintStack(PrettyStackTraceHead->get(), OS);
     55   OS.flush();
     56 }
     57 
     58 // Integrate with crash reporter libraries.
     59 #if defined (__APPLE__) && HAVE_CRASHREPORTERCLIENT_H
     60 //  If any clients of llvm try to link to libCrashReporterClient.a themselves,
     61 //  only one crash info struct will be used.
     62 extern "C" {
     63 CRASH_REPORTER_CLIENT_HIDDEN
     64 struct crashreporter_annotations_t gCRAnnotations
     65         __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION)))
     66         = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0 };
     67 }
     68 #elif defined (__APPLE__) && HAVE_CRASHREPORTER_INFO
     69 static const char *__crashreporter_info__ = 0;
     70 asm(".desc ___crashreporter_info__, 0x10");
     71 #endif
     72 
     73 
     74 /// CrashHandler - This callback is run if a fatal signal is delivered to the
     75 /// process, it prints the pretty stack trace.
     76 static void CrashHandler(void *) {
     77 #ifndef __APPLE__
     78   // On non-apple systems, just emit the crash stack trace to stderr.
     79   PrintCurStackTrace(errs());
     80 #else
     81   // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
     82   // put it into __crashreporter_info__.
     83   SmallString<2048> TmpStr;
     84   {
     85     raw_svector_ostream Stream(TmpStr);
     86     PrintCurStackTrace(Stream);
     87   }
     88 
     89   if (!TmpStr.empty()) {
     90 #ifdef HAVE_CRASHREPORTERCLIENT_H
     91     // Cast to void to avoid warning.
     92     (void)CRSetCrashLogMessage(std::string(TmpStr.str()).c_str());
     93 #elif HAVE_CRASHREPORTER_INFO
     94     __crashreporter_info__ = strdup(std::string(TmpStr.str()).c_str());
     95 #endif
     96     errs() << TmpStr.str();
     97   }
     98 
     99 #endif
    100 }
    101 
    102 PrettyStackTraceEntry::PrettyStackTraceEntry() {
    103   // Link ourselves.
    104   NextEntry = PrettyStackTraceHead->get();
    105   PrettyStackTraceHead->set(this);
    106 }
    107 
    108 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
    109   // Do nothing if PrettyStackTraceHead is uninitialized. This can only happen
    110   // if a shutdown occurred after we created the PrettyStackTraceEntry. That
    111   // does occur in the following idiom:
    112   //
    113   // PrettyStackTraceProgram X(...);
    114   // llvm_shutdown_obj Y;
    115   //
    116   // Without this check, we may end up removing ourselves from the stack trace
    117   // after PrettyStackTraceHead has already been destroyed.
    118   if (!PrettyStackTraceHead.isConstructed())
    119     return;
    120 
    121   assert(PrettyStackTraceHead->get() == this &&
    122          "Pretty stack trace entry destruction is out of order");
    123   PrettyStackTraceHead->set(getNextEntry());
    124 }
    125 
    126 void PrettyStackTraceString::print(raw_ostream &OS) const {
    127   OS << Str << "\n";
    128 }
    129 
    130 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
    131   OS << "Program arguments: ";
    132   // Print the argument list.
    133   for (unsigned i = 0, e = ArgC; i != e; ++i)
    134     OS << ArgV[i] << ' ';
    135   OS << '\n';
    136 }
    137 
    138 static bool RegisterCrashPrinter() {
    139   sys::AddSignalHandler(CrashHandler, nullptr);
    140   return false;
    141 }
    142 
    143 void llvm::EnablePrettyStackTrace() {
    144   // The first time this is called, we register the crash printer.
    145   static bool HandlerRegistered = RegisterCrashPrinter();
    146   (void)HandlerRegistered;
    147 }
    148 
    149 void LLVMEnablePrettyStackTrace() {
    150   EnablePrettyStackTrace();
    151 }
    152