LLVM  8.0.0svn
PrettyStackTrace.cpp
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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 
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"
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.
44 
45 namespace llvm {
47  PrettyStackTraceEntry *Prev = nullptr;
48  while (Head)
49  std::tie(Prev, Head, Head->NextEntry) =
50  std::make_tuple(Head, Head->NextEntry, Prev);
51  return Prev;
52 }
53 }
54 
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.
59  unsigned ID = 0;
60  PrettyStackTraceEntry *ReversedStack =
62  for (const PrettyStackTraceEntry *Entry = ReversedStack; Entry;
63  Entry = Entry->getNextEntry()) {
64  OS << ID++ << ".\t";
65  sys::Watchdog W(5);
66  Entry->print(OS);
67  }
68  llvm::ReverseStackTrace(ReversedStack);
69 }
70 
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;
75 
76  // If there are pretty stack frames registered, walk and emit them.
77  OS << "Stack dump:\n";
78 
79  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 static void CrashHandler(void *) {
106 #ifndef __APPLE__
107  // On non-apple systems, just emit the crash stack trace to stderr.
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 }
130 
131 // defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
132 #endif
133 
135 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
136  // Link ourselves.
137  NextEntry = PrettyStackTraceHead;
138  PrettyStackTraceHead = this;
139 #endif
140 }
141 
143 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
144  assert(PrettyStackTraceHead == this &&
145  "Pretty stack trace entry destruction is out of order");
146  PrettyStackTraceHead = NextEntry;
147 #endif
148 }
149 
150 void PrettyStackTraceString::print(raw_ostream &OS) const { OS << Str << "\n"; }
151 
153  va_list AP;
154  va_start(AP, Format);
155  const int SizeOrError = vsnprintf(nullptr, 0, Format, AP);
156  va_end(AP);
157  if (SizeOrError < 0) {
158  return;
159  }
160 
161  const int Size = SizeOrError + 1; // '\0'
162  Str.resize(Size);
163  va_start(AP, Format);
164  vsnprintf(Str.data(), Size, Format, AP);
165  va_end(AP);
166 }
167 
168 void PrettyStackTraceFormat::print(raw_ostream &OS) const { OS << Str << "\n"; }
169 
171  OS << "Program arguments: ";
172  // Print the argument list.
173  for (unsigned i = 0, e = ArgC; i != e; ++i)
174  OS << ArgV[i] << ' ';
175  OS << '\n';
176 }
177 
178 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
179 static bool RegisterCrashPrinter() {
181  return false;
182 }
183 #endif
184 
186 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
187  // The first time this is called, we register the crash printer.
188  static bool HandlerRegistered = RegisterCrashPrinter();
189  (void)HandlerRegistered;
190 #endif
191 }
192 
194 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
195  return PrettyStackTraceHead;
196 #else
197  return nullptr;
198 #endif
199 }
200 
201 void llvm::RestorePrettyStackState(const void *Top) {
202 #if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES
204  static_cast<PrettyStackTraceEntry *>(const_cast<void *>(Top));
205 #endif
206 }
207 
210 }
void RestorePrettyStackState(const void *State)
Restores the topmost element of the "pretty" stack state to State, which should come from a previous ...
raw_ostream & errs()
This returns a reference to a raw_ostream for standard error.
This class represents lattice values for constants.
Definition: AllocatorList.h:24
A raw_ostream that writes to an SmallVector or SmallString.
Definition: raw_ostream.h:510
This class provides an abstraction for a timeout around an operation that must complete in a given am...
Definition: Watchdog.h:26
void EnablePrettyStackTrace()
StringRef str() const
Explicit conversion to StringRef.
Definition: SmallString.h:267
#define LLVM_THREAD_LOCAL
LLVM_THREAD_LOCAL A thread-local storage specifier which can be used with globals, extern globals, and static globals.
Definition: Compiler.h:504
SmallString - A SmallString is just a SmallVector with methods and accessors that make it work better...
Definition: SmallString.h:26
void print(raw_ostream &OS) const override
print - Emit information about this stack frame to OS.
void LLVMEnablePrettyStackTrace()
Enable LLVM&#39;s built-in stack trace code.
static void PrintCurStackTrace(raw_ostream &OS)
PrintCurStackTrace - Print the current stack trace to the specified stream.
PrettyStackTraceEntry - This class is used to represent a frame of the "pretty" stack trace that is d...
const void * SavePrettyStackState()
Returns the topmost element of the "pretty" stack state.
static void PrintStack(raw_ostream &OS)
PrettyStackTraceFormat(const char *Format,...)
static LLVM_THREAD_LOCAL PrettyStackTraceEntry * PrettyStackTraceHead
static bool RegisterCrashPrinter()
void print(raw_ostream &OS) const override
print - Emit information about this stack frame to OS.
static void CrashHandler(void *)
CrashHandler - This callback is run if a fatal signal is delivered to the process, it prints the pretty stack trace.
void print(raw_ostream &OS) const override
print - Emit information about this stack frame to OS.
PrettyStackTraceEntry * ReverseStackTrace(PrettyStackTraceEntry *Head)
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:56
const char * c_str()
Definition: SmallString.h:270
uint32_t Size
Definition: Profile.cpp:47
void AddSignalHandler(SignalHandlerCallback FnPtr, void *Cookie)
Add a function to be called when an abort/kill signal is delivered to the process.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:46
const PrettyStackTraceEntry * getNextEntry() const
getNextEntry - Return the next entry in the list of frames.