1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
| //===- Signals.cpp - Signal Handling support --------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines some helpful functions for dealing with the possibility of
// Unix signals occurring while your program is running.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Signals.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/Program.h"
#include "llvm/Support/StringSaver.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Options.h"
#include <vector>
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
using namespace llvm;
// Use explicit storage to avoid accessing cl::opt in a signal handler.
static bool DisableSymbolicationFlag = false;
static cl::opt<bool, true>
DisableSymbolication("disable-symbolication",
cl::desc("Disable symbolizing crash backtraces."),
cl::location(DisableSymbolicationFlag), cl::Hidden);
// Callbacks to run in signal handler must be lock-free because a signal handler
// could be running as we add new callbacks. We don't add unbounded numbers of
// callbacks, an array is therefore sufficient.
struct CallbackAndCookie {
sys::SignalHandlerCallback Callback;
void *Cookie;
enum class Status { Empty, Initializing, Initialized, Executing };
std::atomic<Status> Flag;
};
static constexpr size_t MaxSignalHandlerCallbacks = 8;
static CallbackAndCookie CallBacksToRun[MaxSignalHandlerCallbacks];
// Signal-safe.
void sys::RunSignalHandlers() {
for (size_t I = 0; I < MaxSignalHandlerCallbacks; ++I) {
auto &RunMe = CallBacksToRun[I];
auto Expected = CallbackAndCookie::Status::Initialized;
auto Desired = CallbackAndCookie::Status::Executing;
if (!RunMe.Flag.compare_exchange_strong(Expected, Desired))
continue;
(*RunMe.Callback)(RunMe.Cookie);
RunMe.Callback = nullptr;
RunMe.Cookie = nullptr;
RunMe.Flag.store(CallbackAndCookie::Status::Empty);
}
}
// Signal-safe.
static void insertSignalHandler(sys::SignalHandlerCallback FnPtr,
void *Cookie) {
for (size_t I = 0; I < MaxSignalHandlerCallbacks; ++I) {
auto &SetMe = CallBacksToRun[I];
auto Expected = CallbackAndCookie::Status::Empty;
auto Desired = CallbackAndCookie::Status::Initializing;
if (!SetMe.Flag.compare_exchange_strong(Expected, Desired))
continue;
SetMe.Callback = FnPtr;
SetMe.Cookie = Cookie;
SetMe.Flag.store(CallbackAndCookie::Status::Initialized);
return;
}
report_fatal_error("too many signal callbacks already registered");
}
static bool findModulesAndOffsets(void **StackTrace, int Depth,
const char **Modules, intptr_t *Offsets,
const char *MainExecutableName,
StringSaver &StrPool);
/// Format a pointer value as hexadecimal. Zero pad it out so its always the
/// same width.
static FormattedNumber format_ptr(void *PC) {
// Each byte is two hex digits plus 2 for the 0x prefix.
unsigned PtrWidth = 2 + 2 * sizeof(void *);
return format_hex((uint64_t)PC, PtrWidth);
}
/// Helper that launches llvm-symbolizer and symbolizes a backtrace.
LLVM_ATTRIBUTE_USED
static bool printSymbolizedStackTrace(StringRef Argv0, void **StackTrace,
int Depth, llvm::raw_ostream &OS) {
if (DisableSymbolicationFlag)
return false;
// Don't recursively invoke the llvm-symbolizer binary.
if (Argv0.find("llvm-symbolizer") != std::string::npos)
return false;
// FIXME: Subtract necessary number from StackTrace entries to turn return addresses
// into actual instruction addresses.
// Use llvm-symbolizer tool to symbolize the stack traces. First look for it
// alongside our binary, then in $PATH.
ErrorOr<std::string> LLVMSymbolizerPathOrErr = std::error_code();
if (!Argv0.empty()) {
StringRef Parent = llvm::sys::path::parent_path(Argv0);
if (!Parent.empty())
LLVMSymbolizerPathOrErr = sys::findProgramByName("llvm-symbolizer", Parent);
}
if (!LLVMSymbolizerPathOrErr)
LLVMSymbolizerPathOrErr = sys::findProgramByName("llvm-symbolizer");
if (!LLVMSymbolizerPathOrErr)
return false;
const std::string &LLVMSymbolizerPath = *LLVMSymbolizerPathOrErr;
// If we don't know argv0 or the address of main() at this point, try
// to guess it anyway (it's possible on some platforms).
std::string MainExecutableName =
sys::fs::exists(Argv0) ? (std::string)Argv0
: sys::fs::getMainExecutable(nullptr, nullptr);
BumpPtrAllocator Allocator;
StringSaver StrPool(Allocator);
std::vector<const char *> Modules(Depth, nullptr);
std::vector<intptr_t> Offsets(Depth, 0);
if (!findModulesAndOffsets(StackTrace, Depth, Modules.data(), Offsets.data(),
MainExecutableName.c_str(), StrPool))
return false;
int InputFD;
SmallString<32> InputFile, OutputFile;
sys::fs::createTemporaryFile("symbolizer-input", "", InputFD, InputFile);
sys::fs::createTemporaryFile("symbolizer-output", "", OutputFile);
FileRemover InputRemover(InputFile.c_str());
FileRemover OutputRemover(OutputFile.c_str());
{
raw_fd_ostream Input(InputFD, true);
for (int i = 0; i < Depth; i++) {
if (Modules[i])
Input << Modules[i] << " " << (void*)Offsets[i] << "\n";
}
}
Optional<StringRef> Redirects[] = {StringRef(InputFile),
StringRef(OutputFile), StringRef("")};
StringRef Args[] = {"llvm-symbolizer", "--functions=linkage", "--inlining",
#ifdef _WIN32
// Pass --relative-address on Windows so that we don't
// have to add ImageBase from PE file.
// FIXME: Make this the default for llvm-symbolizer.
"--relative-address",
#endif
"--demangle"};
int RunResult =
sys::ExecuteAndWait(LLVMSymbolizerPath, Args, None, Redirects);
if (RunResult != 0)
return false;
// This report format is based on the sanitizer stack trace printer. See
// sanitizer_stacktrace_printer.cc in compiler-rt.
auto OutputBuf = MemoryBuffer::getFile(OutputFile.c_str());
if (!OutputBuf)
return false;
StringRef Output = OutputBuf.get()->getBuffer();
SmallVector<StringRef, 32> Lines;
Output.split(Lines, "\n");
auto CurLine = Lines.begin();
int frame_no = 0;
for (int i = 0; i < Depth; i++) {
auto PrintLineHeader = [&]() {
OS << right_justify(formatv("#{0}", frame_no++).str(),
std::log10(Depth) + 2)
<< ' ' << format_ptr(StackTrace[i]) << ' ';
};
if (!Modules[i]) {
PrintLineHeader();
OS << '\n';
continue;
}
// Read pairs of lines (function name and file/line info) until we
// encounter empty line.
for (;;) {
if (CurLine == Lines.end())
return false;
StringRef FunctionName = *CurLine++;
if (FunctionName.empty())
break;
PrintLineHeader();
if (!FunctionName.startswith("??"))
OS << FunctionName << ' ';
if (CurLine == Lines.end())
return false;
StringRef FileLineInfo = *CurLine++;
if (!FileLineInfo.startswith("??"))
OS << FileLineInfo;
else
OS << "(" << Modules[i] << '+' << format_hex(Offsets[i], 0) << ")";
OS << "\n";
}
}
return true;
}
// Include the platform-specific parts of this class.
#ifdef LLVM_ON_UNIX
#include "Unix/Signals.inc"
#endif
#ifdef _WIN32
#include "Windows/Signals.inc"
#endif
|