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