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"
27 #ifdef HAVE_CRASHREPORTERCLIENT_H
28 #include <CrashReporterClient.h>
33 // If backtrace support is not enabled, compile out support for pretty stack
34 // traces. This has the secondary effect of not requiring thread local storage
35 // when backtrace support is disabled.
36 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
38 // We need a thread local pointer to manage the stack of our stack trace
39 // objects, but we *really* cannot tolerate destructors running and do not want
40 // to pay any overhead of synchronizing. As a consequence, we use a raw
41 // thread-local variable.
42 static LLVM_THREAD_LOCAL PrettyStackTraceEntry *PrettyStackTraceHead = nullptr;
45 PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *Head) {
46 PrettyStackTraceEntry *Prev = nullptr;
48 std::tie(Prev, Head, Head->NextEntry) =
49 std::make_tuple(Head, Head->NextEntry, Prev);
54 static void PrintStack(raw_ostream &OS) {
55 // Print out the stack in reverse order. To avoid recursion (which is likely
56 // to fail if we crashed due to stack overflow), we do an up-front pass to
57 // reverse the stack, then print it, then reverse it again.
59 PrettyStackTraceEntry *ReversedStack =
60 llvm::ReverseStackTrace(PrettyStackTraceHead);
61 for (const PrettyStackTraceEntry *Entry = ReversedStack; Entry;
62 Entry = Entry->getNextEntry()) {
67 llvm::ReverseStackTrace(ReversedStack);
70 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
71 static void PrintCurStackTrace(raw_ostream &OS) {
72 // Don't print an empty trace.
73 if (!PrettyStackTraceHead) return;
75 // If there are pretty stack frames registered, walk and emit them.
76 OS << "Stack dump:\n";
82 // Integrate with crash reporter libraries.
83 #if defined (__APPLE__) && defined(HAVE_CRASHREPORTERCLIENT_H)
84 // If any clients of llvm try to link to libCrashReporterClient.a themselves,
85 // only one crash info struct will be used.
87 CRASH_REPORTER_CLIENT_HIDDEN
88 struct crashreporter_annotations_t gCRAnnotations
89 __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION)))
90 = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0 };
92 #elif defined(__APPLE__) && HAVE_CRASHREPORTER_INFO
93 extern "C" const char *__crashreporter_info__
94 __attribute__((visibility("hidden"))) = 0;
95 asm(".desc ___crashreporter_info__, 0x10");
98 /// CrashHandler - This callback is run if a fatal signal is delivered to the
99 /// process, it prints the pretty stack trace.
100 static void CrashHandler(void *) {
102 // On non-apple systems, just emit the crash stack trace to stderr.
103 PrintCurStackTrace(errs());
105 // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
106 // put it into __crashreporter_info__.
107 SmallString<2048> TmpStr;
109 raw_svector_ostream Stream(TmpStr);
110 PrintCurStackTrace(Stream);
113 if (!TmpStr.empty()) {
114 #ifdef HAVE_CRASHREPORTERCLIENT_H
115 // Cast to void to avoid warning.
116 (void)CRSetCrashLogMessage(std::string(TmpStr.str()).c_str());
117 #elif HAVE_CRASHREPORTER_INFO
118 __crashreporter_info__ = strdup(std::string(TmpStr.str()).c_str());
120 errs() << TmpStr.str();
126 // defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
129 PrettyStackTraceEntry::PrettyStackTraceEntry() {
130 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
132 NextEntry = PrettyStackTraceHead;
133 PrettyStackTraceHead = this;
137 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
138 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
139 assert(PrettyStackTraceHead == this &&
140 "Pretty stack trace entry destruction is out of order");
141 PrettyStackTraceHead = NextEntry;
145 void PrettyStackTraceString::print(raw_ostream &OS) const { OS << Str << "\n"; }
147 PrettyStackTraceFormat::PrettyStackTraceFormat(const char *Format, ...) {
149 va_start(AP, Format);
150 const int SizeOrError = vsnprintf(nullptr, 0, Format, AP);
152 if (SizeOrError < 0) {
156 const int Size = SizeOrError + 1; // '\0'
158 va_start(AP, Format);
159 vsnprintf(Str.data(), Size, Format, AP);
163 void PrettyStackTraceFormat::print(raw_ostream &OS) const { OS << Str << "\n"; }
165 void PrettyStackTraceProgram::print(raw_ostream &OS) const {
166 OS << "Program arguments: ";
167 // Print the argument list.
168 for (unsigned i = 0, e = ArgC; i != e; ++i)
169 OS << ArgV[i] << ' ';
173 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
174 static bool RegisterCrashPrinter() {
175 sys::AddSignalHandler(CrashHandler, nullptr);
180 void llvm::EnablePrettyStackTrace() {
181 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
182 // The first time this is called, we register the crash printer.
183 static bool HandlerRegistered = RegisterCrashPrinter();
184 (void)HandlerRegistered;
188 const void *llvm::SavePrettyStackState() {
189 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
190 return PrettyStackTraceHead;
196 void llvm::RestorePrettyStackState(const void *Top) {
197 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
198 PrettyStackTraceHead =
199 static_cast<PrettyStackTraceEntry *>(const_cast<void *>(Top));
203 void LLVMEnablePrettyStackTrace() {
204 EnablePrettyStackTrace();