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 
109