1 //===- PrettyStackTrace.cpp - Pretty Crash Handling -----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines some helpful functions for dealing with the possibility of
11 // Unix signals occurring while your program is running.
13 //===----------------------------------------------------------------------===//
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"
28 #ifdef HAVE_CRASHREPORTERCLIENT_H
29 #include <CrashReporterClient.h>
34 // If backtrace support is not enabled, compile out support for pretty stack
35 // traces. This has the secondary effect of not requiring thread local storage
36 // when backtrace support is disabled.
37 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
39 // We need a thread local pointer to manage the stack of our stack trace
40 // objects, but we *really* cannot tolerate destructors running and do not want
41 // to pay any overhead of synchronizing. As a consequence, we use a raw
42 // thread-local variable.
43 static LLVM_THREAD_LOCAL PrettyStackTraceEntry *PrettyStackTraceHead = nullptr;
46 PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *Head) {
47 PrettyStackTraceEntry *Prev = nullptr;
49 std::tie(Prev, Head, Head->NextEntry) =
50 std::make_tuple(Head, Head->NextEntry, Prev);
55 static void PrintStack(raw_ostream &OS) {
56 // Print out the stack in reverse order. To avoid recursion (which is likely
57 // to fail if we crashed due to stack overflow), we do an up-front pass to
58 // reverse the stack, then print it, then reverse it again.
60 PrettyStackTraceEntry *ReversedStack =
61 llvm::ReverseStackTrace(PrettyStackTraceHead);
62 for (const PrettyStackTraceEntry *Entry = ReversedStack; Entry;
63 Entry = Entry->getNextEntry()) {
68 llvm::ReverseStackTrace(ReversedStack);
71 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
72 static void PrintCurStackTrace(raw_ostream &OS) {
73 // Don't print an empty trace.
74 if (!PrettyStackTraceHead) return;
76 // If there are pretty stack frames registered, walk and emit them.
77 OS << "Stack dump:\n";
83 // Integrate with crash reporter libraries.
84 #if defined (__APPLE__) && defined(HAVE_CRASHREPORTERCLIENT_H)
85 // If any clients of llvm try to link to libCrashReporterClient.a themselves,
86 // only one crash info struct will be used.
88 CRASH_REPORTER_CLIENT_HIDDEN
89 struct crashreporter_annotations_t gCRAnnotations
90 __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION)))
91 = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0 };
93 #elif defined(__APPLE__) && HAVE_CRASHREPORTER_INFO
94 extern "C" const char *__crashreporter_info__
95 __attribute__((visibility("hidden"))) = 0;
96 asm(".desc ___crashreporter_info__, 0x10");
99 /// CrashHandler - This callback is run if a fatal signal is delivered to the
100 /// process, it prints the pretty stack trace.
101 static void CrashHandler(void *) {
103 // On non-apple systems, just emit the crash stack trace to stderr.
104 PrintCurStackTrace(errs());
106 // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
107 // put it into __crashreporter_info__.
108 SmallString<2048> TmpStr;
110 raw_svector_ostream Stream(TmpStr);
111 PrintCurStackTrace(Stream);
114 if (!TmpStr.empty()) {
115 #ifdef HAVE_CRASHREPORTERCLIENT_H
116 // Cast to void to avoid warning.
117 (void)CRSetCrashLogMessage(std::string(TmpStr.str()).c_str());
118 #elif HAVE_CRASHREPORTER_INFO
119 __crashreporter_info__ = strdup(std::string(TmpStr.str()).c_str());
121 errs() << TmpStr.str();
127 // defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
130 PrettyStackTraceEntry::PrettyStackTraceEntry() {
131 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
133 NextEntry = PrettyStackTraceHead;
134 PrettyStackTraceHead = this;
138 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
139 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
140 assert(PrettyStackTraceHead == this &&
141 "Pretty stack trace entry destruction is out of order");
142 PrettyStackTraceHead = NextEntry;
146 void PrettyStackTraceString::print(raw_ostream &OS) const { OS << Str << "\n"; }
148 PrettyStackTraceFormat::PrettyStackTraceFormat(const char *Format, ...) {
150 va_start(AP, Format);
151 const int SizeOrError = vsnprintf(nullptr, 0, Format, AP);
153 if (SizeOrError < 0) {
157 const int Size = SizeOrError + 1; // '\0'
159 va_start(AP, Format);
160 vsnprintf(Str.data(), Size, Format, AP);
164 void PrettyStackTraceFormat::print(raw_ostream &OS) const { OS << Str << "\n"; }
166 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
167 OS << "Program arguments: ";
168 // Print the argument list.
169 for (unsigned i = 0, e = ArgC; i != e; ++i)
170 OS << ArgV[i] << ' ';
174 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
175 static bool RegisterCrashPrinter() {
176 sys::AddSignalHandler(CrashHandler, nullptr);
181 void llvm::EnablePrettyStackTrace() {
182 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
183 // The first time this is called, we register the crash printer.
184 static bool HandlerRegistered = RegisterCrashPrinter();
185 (void)HandlerRegistered;
189 const void *llvm::SavePrettyStackState() {
190 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
191 return PrettyStackTraceHead;
197 void llvm::RestorePrettyStackState(const void *Top) {
198 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
199 PrettyStackTraceHead =
200 static_cast<PrettyStackTraceEntry *>(const_cast<void *>(Top));
204 void LLVMEnablePrettyStackTrace() {
205 EnablePrettyStackTrace();