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/ErrorHandling.h"
17 #include "llvm/ADT/SmallString.h"
18 #include "llvm/Config/config.h" // Get autoconf configuration settings
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/Signals.h"
21 #include "llvm/Support/Watchdog.h"
22 #include "llvm/Support/raw_ostream.h"
23
24 #ifdef HAVE_CRASHREPORTERCLIENT_H
25 #include <CrashReporterClient.h>
26 #endif
27
28 using namespace llvm;
29
30 // If backtrace support is not enabled, compile out support for pretty stack
31 // traces. This has the secondary effect of not requiring thread local storage
32 // when backtrace support is disabled.
33 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
34
35 // We need a thread local pointer to manage the stack of our stack trace
36 // objects, but we *really* cannot tolerate destructors running and do not want
37 // to pay any overhead of synchronizing. As a consequence, we use a raw
38 // thread-local variable.
39 static LLVM_THREAD_LOCAL const PrettyStackTraceEntry *PrettyStackTraceHead =
40 nullptr;
41
PrintStack(const PrettyStackTraceEntry * Entry,raw_ostream & OS)42 static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
43 unsigned NextID = 0;
44 if (Entry->getNextEntry())
45 NextID = PrintStack(Entry->getNextEntry(), OS);
46 OS << NextID << ".\t";
47 {
48 sys::Watchdog W(5);
49 Entry->print(OS);
50 }
51
52 return NextID+1;
53 }
54
55 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
PrintCurStackTrace(raw_ostream & OS)56 static void PrintCurStackTrace(raw_ostream &OS) {
57 // Don't print an empty trace.
58 if (!PrettyStackTraceHead) return;
59
60 // If there are pretty stack frames registered, walk and emit them.
61 OS << "Stack dump:\n";
62
63 PrintStack(PrettyStackTraceHead, OS);
64 OS.flush();
65 }
66
67 // Integrate with crash reporter libraries.
68 #if defined (__APPLE__) && HAVE_CRASHREPORTERCLIENT_H
69 // If any clients of llvm try to link to libCrashReporterClient.a themselves,
70 // only one crash info struct will be used.
71 extern "C" {
72 CRASH_REPORTER_CLIENT_HIDDEN
73 struct crashreporter_annotations_t gCRAnnotations
74 __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION)))
75 = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0 };
76 }
77 #elif defined (__APPLE__) && HAVE_CRASHREPORTER_INFO
78 static const char *__crashreporter_info__ = 0;
79 asm(".desc ___crashreporter_info__, 0x10");
80 #endif
81
82
83 /// CrashHandler - This callback is run if a fatal signal is delivered to the
84 /// process, it prints the pretty stack trace.
CrashHandler(void *)85 static void CrashHandler(void *) {
86 #ifndef __APPLE__
87 // On non-apple systems, just emit the crash stack trace to stderr.
88 PrintCurStackTrace(errs());
89 #else
90 // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
91 // put it into __crashreporter_info__.
92 SmallString<2048> TmpStr;
93 {
94 raw_svector_ostream Stream(TmpStr);
95 PrintCurStackTrace(Stream);
96 }
97
98 if (!TmpStr.empty()) {
99 #ifdef HAVE_CRASHREPORTERCLIENT_H
100 // Cast to void to avoid warning.
101 (void)CRSetCrashLogMessage(std::string(TmpStr.str()).c_str());
102 #elif HAVE_CRASHREPORTER_INFO
103 __crashreporter_info__ = strdup(std::string(TmpStr.str()).c_str());
104 #endif
105 errs() << TmpStr.str();
106 }
107
108 #endif
109 }
110
111 // defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
112 #endif
113
PrettyStackTraceEntry()114 PrettyStackTraceEntry::PrettyStackTraceEntry() {
115 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
116 // Link ourselves.
117 NextEntry = PrettyStackTraceHead;
118 PrettyStackTraceHead = this;
119 #endif
120 }
121
~PrettyStackTraceEntry()122 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
123 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
124 assert(PrettyStackTraceHead == this &&
125 "Pretty stack trace entry destruction is out of order");
126 PrettyStackTraceHead = getNextEntry();
127 #endif
128 }
129
print(raw_ostream & OS) const130 void PrettyStackTraceString::print(raw_ostream &OS) const {
131 OS << Str << "\n";
132 }
133
print(raw_ostream & OS) const134 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
135 OS << "Program arguments: ";
136 // Print the argument list.
137 for (unsigned i = 0, e = ArgC; i != e; ++i)
138 OS << ArgV[i] << ' ';
139 OS << '\n';
140 }
141
142 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
RegisterCrashPrinter()143 static bool RegisterCrashPrinter() {
144 sys::AddSignalHandler(CrashHandler, nullptr);
145 return false;
146 }
147 #endif
148
EnablePrettyStackTrace()149 void llvm::EnablePrettyStackTrace() {
150 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
151 // The first time this is called, we register the crash printer.
152 static bool HandlerRegistered = RegisterCrashPrinter();
153 (void)HandlerRegistered;
154 #endif
155 }
156
SavePrettyStackState()157 const void* llvm::SavePrettyStackState() {
158 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
159 return PrettyStackTraceHead;
160 #else
161 return nullptr;
162 #endif
163 }
164
RestorePrettyStackState(const void * Top)165 void llvm::RestorePrettyStackState(const void* Top) {
166 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
167 PrettyStackTraceHead = (const PrettyStackTraceEntry*)Top;
168 #endif
169 }
170
LLVMEnablePrettyStackTrace()171 void LLVMEnablePrettyStackTrace() {
172 EnablePrettyStackTrace();
173 }
174