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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 : #include <cstdarg>
25 : #include <cstdio>
26 : #include <tuple>
27 :
28 : #ifdef HAVE_CRASHREPORTERCLIENT_H
29 : #include <CrashReporterClient.h>
30 : #endif
31 :
32 : using namespace llvm;
33 :
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
38 :
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;
44 :
45 : namespace llvm {
46 0 : PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *Head) {
47 0 : PrettyStackTraceEntry *Prev = nullptr;
48 0 : while (Head)
49 0 : std::tie(Prev, Head, Head->NextEntry) =
50 0 : std::make_tuple(Head, Head->NextEntry, Prev);
51 0 : return Prev;
52 : }
53 : }
54 :
55 0 : 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.
59 : unsigned ID = 0;
60 : PrettyStackTraceEntry *ReversedStack =
61 0 : llvm::ReverseStackTrace(PrettyStackTraceHead);
62 0 : for (const PrettyStackTraceEntry *Entry = ReversedStack; Entry;
63 0 : Entry = Entry->getNextEntry()) {
64 0 : OS << ID++ << ".\t";
65 0 : sys::Watchdog W(5);
66 0 : Entry->print(OS);
67 : }
68 0 : llvm::ReverseStackTrace(ReversedStack);
69 0 : }
70 :
71 : /// PrintCurStackTrace - Print the current stack trace to the specified stream.
72 0 : static void PrintCurStackTrace(raw_ostream &OS) {
73 : // Don't print an empty trace.
74 0 : if (!PrettyStackTraceHead) return;
75 :
76 : // If there are pretty stack frames registered, walk and emit them.
77 0 : OS << "Stack dump:\n";
78 :
79 0 : PrintStack(OS);
80 : OS.flush();
81 : }
82 :
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.
87 : extern "C" {
88 : CRASH_REPORTER_CLIENT_HIDDEN
89 : struct crashreporter_annotations_t gCRAnnotations
90 : __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION)))
91 : #if CRASHREPORTER_ANNOTATIONS_VERSION < 5
92 : = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0 };
93 : #else
94 : = { CRASHREPORTER_ANNOTATIONS_VERSION, 0, 0, 0, 0, 0, 0, 0 };
95 : #endif
96 : }
97 : #elif defined(__APPLE__) && HAVE_CRASHREPORTER_INFO
98 : extern "C" const char *__crashreporter_info__
99 : __attribute__((visibility("hidden"))) = 0;
100 : asm(".desc ___crashreporter_info__, 0x10");
101 : #endif
102 :
103 : /// CrashHandler - This callback is run if a fatal signal is delivered to the
104 : /// process, it prints the pretty stack trace.
105 0 : static void CrashHandler(void *) {
106 : #ifndef __APPLE__
107 : // On non-apple systems, just emit the crash stack trace to stderr.
108 0 : PrintCurStackTrace(errs());
109 : #else
110 : // Otherwise, emit to a smallvector of chars, send *that* to stderr, but also
111 : // put it into __crashreporter_info__.
112 : SmallString<2048> TmpStr;
113 : {
114 : raw_svector_ostream Stream(TmpStr);
115 : PrintCurStackTrace(Stream);
116 : }
117 :
118 : if (!TmpStr.empty()) {
119 : #ifdef HAVE_CRASHREPORTERCLIENT_H
120 : // Cast to void to avoid warning.
121 : (void)CRSetCrashLogMessage(TmpStr.c_str());
122 : #elif HAVE_CRASHREPORTER_INFO
123 : __crashreporter_info__ = strdup(TmpStr.c_str());
124 : #endif
125 : errs() << TmpStr.str();
126 : }
127 :
128 : #endif
129 0 : }
130 :
131 : // defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
132 : #endif
133 :
134 176351781 : PrettyStackTraceEntry::PrettyStackTraceEntry() {
135 : #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
136 : // Link ourselves.
137 176351781 : NextEntry = PrettyStackTraceHead;
138 176351781 : PrettyStackTraceHead = this;
139 : #endif
140 176351781 : }
141 :
142 352700410 : PrettyStackTraceEntry::~PrettyStackTraceEntry() {
143 : #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
144 : assert(PrettyStackTraceHead == this &&
145 : "Pretty stack trace entry destruction is out of order");
146 176350205 : PrettyStackTraceHead = NextEntry;
147 : #endif
148 176350205 : }
149 0 :
150 : void PrettyStackTraceString::print(raw_ostream &OS) const { OS << Str << "\n"; }
151 :
152 : PrettyStackTraceFormat::PrettyStackTraceFormat(const char *Format, ...) {
153 : va_list AP;
154 : va_start(AP, Format);
155 0 : const int SizeOrError = vsnprintf(nullptr, 0, Format, AP);
156 352700410 : va_end(AP);
157 : if (SizeOrError < 0) {
158 : return;
159 : }
160 176350205 :
161 : const int Size = SizeOrError + 1; // '\0'
162 176350205 : Str.resize(Size);
163 : va_start(AP, Format);
164 0 : vsnprintf(Str.data(), Size, Format, AP);
165 : va_end(AP);
166 0 : }
167 :
168 0 : void PrettyStackTraceFormat::print(raw_ostream &OS) const { OS << Str << "\n"; }
169 0 :
170 0 : void PrettyStackTraceProgram::print(raw_ostream &OS) const {
171 0 : OS << "Program arguments: ";
172 0 : // Print the argument list.
173 : for (unsigned i = 0, e = ArgC; i != e; ++i)
174 : OS << ArgV[i] << ' ';
175 0 : OS << '\n';
176 0 : }
177 0 :
178 0 : #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
179 0 : static bool RegisterCrashPrinter() {
180 : sys::AddSignalHandler(CrashHandler, nullptr);
181 : return false;
182 0 : }
183 : #endif
184 0 :
185 0 : void llvm::EnablePrettyStackTrace() {
186 : #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
187 0 : // The first time this is called, we register the crash printer.
188 0 : static bool HandlerRegistered = RegisterCrashPrinter();
189 : (void)HandlerRegistered;
190 0 : #endif
191 : }
192 :
193 : const void *llvm::SavePrettyStackState() {
194 166312 : #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
195 : return PrettyStackTraceHead;
196 : #else
197 : return nullptr;
198 : #endif
199 166312 : }
200 :
201 : void llvm::RestorePrettyStackState(const void *Top) {
202 332624 : #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
203 : PrettyStackTraceHead =
204 : static_cast<PrettyStackTraceEntry *>(const_cast<void *>(Top));
205 166312 : #endif
206 : }
207 36870 :
208 : void LLVMEnablePrettyStackTrace() {
209 36870 : EnablePrettyStackTrace();
210 : }
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