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