1 //===- Signals.cpp - Signal Handling support --------------------*- C++ -*-===//
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/ADT/STLExtras.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/Config/config.h"
18 #include "llvm/Support/ErrorOr.h"
19 #include "llvm/Support/FileSystem.h"
20 #include "llvm/Support/FileUtilities.h"
21 #include "llvm/Support/Format.h"
22 #include "llvm/Support/ManagedStatic.h"
23 #include "llvm/Support/MemoryBuffer.h"
24 #include "llvm/Support/Mutex.h"
25 #include "llvm/Support/Program.h"
26 #include "llvm/Support/Signals.h"
27 #include "llvm/Support/StringSaver.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include <vector>
30
31 namespace llvm {
32 using namespace sys;
33
34 //===----------------------------------------------------------------------===//
35 //=== WARNING: Implementation here must contain only TRULY operating system
36 //=== independent code.
37 //===----------------------------------------------------------------------===//
38
39 static ManagedStatic<std::vector<std::pair<void (*)(void *), void *>>>
40 CallBacksToRun;
RunSignalHandlers()41 void sys::RunSignalHandlers() {
42 if (!CallBacksToRun.isConstructed())
43 return;
44 for (auto &I : *CallBacksToRun)
45 I.first(I.second);
46 CallBacksToRun->clear();
47 }
48 }
49
50 using namespace llvm;
51
52 static bool findModulesAndOffsets(void **StackTrace, int Depth,
53 const char **Modules, intptr_t *Offsets,
54 const char *MainExecutableName,
55 StringSaver &StrPool);
56
57 /// Format a pointer value as hexadecimal. Zero pad it out so its always the
58 /// same width.
format_ptr(void * PC)59 static FormattedNumber format_ptr(void *PC) {
60 // Each byte is two hex digits plus 2 for the 0x prefix.
61 unsigned PtrWidth = 2 + 2 * sizeof(void *);
62 return format_hex((uint64_t)PC, PtrWidth);
63 }
64
65 static bool printSymbolizedStackTrace(void **StackTrace, int Depth,
66 llvm::raw_ostream &OS)
67 LLVM_ATTRIBUTE_USED;
68
69 /// Helper that launches llvm-symbolizer and symbolizes a backtrace.
printSymbolizedStackTrace(void ** StackTrace,int Depth,llvm::raw_ostream & OS)70 static bool printSymbolizedStackTrace(void **StackTrace, int Depth,
71 llvm::raw_ostream &OS) {
72 // FIXME: Subtract necessary number from StackTrace entries to turn return addresses
73 // into actual instruction addresses.
74 // Use llvm-symbolizer tool to symbolize the stack traces.
75 ErrorOr<std::string> LLVMSymbolizerPathOrErr =
76 sys::findProgramByName("llvm-symbolizer");
77 if (!LLVMSymbolizerPathOrErr)
78 return false;
79 const std::string &LLVMSymbolizerPath = *LLVMSymbolizerPathOrErr;
80 // We don't know argv0 or the address of main() at this point, but try
81 // to guess it anyway (it's possible on some platforms).
82 std::string MainExecutableName = sys::fs::getMainExecutable(nullptr, nullptr);
83 if (MainExecutableName.empty() ||
84 MainExecutableName.find("llvm-symbolizer") != std::string::npos)
85 return false;
86
87 BumpPtrAllocator Allocator;
88 StringSaver StrPool(Allocator);
89 std::vector<const char *> Modules(Depth, nullptr);
90 std::vector<intptr_t> Offsets(Depth, 0);
91 if (!findModulesAndOffsets(StackTrace, Depth, Modules.data(), Offsets.data(),
92 MainExecutableName.c_str(), StrPool))
93 return false;
94 int InputFD;
95 SmallString<32> InputFile, OutputFile;
96 sys::fs::createTemporaryFile("symbolizer-input", "", InputFD, InputFile);
97 sys::fs::createTemporaryFile("symbolizer-output", "", OutputFile);
98 FileRemover InputRemover(InputFile.c_str());
99 FileRemover OutputRemover(OutputFile.c_str());
100
101 {
102 raw_fd_ostream Input(InputFD, true);
103 for (int i = 0; i < Depth; i++) {
104 if (Modules[i])
105 Input << Modules[i] << " " << (void*)Offsets[i] << "\n";
106 }
107 }
108
109 StringRef InputFileStr(InputFile);
110 StringRef OutputFileStr(OutputFile);
111 StringRef StderrFileStr;
112 const StringRef *Redirects[] = {&InputFileStr, &OutputFileStr,
113 &StderrFileStr};
114 const char *Args[] = {"llvm-symbolizer", "--functions=linkage", "--inlining",
115 #ifdef LLVM_ON_WIN32
116 // Pass --relative-address on Windows so that we don't
117 // have to add ImageBase from PE file.
118 // FIXME: Make this the default for llvm-symbolizer.
119 "--relative-address",
120 #endif
121 "--demangle", nullptr};
122 int RunResult =
123 sys::ExecuteAndWait(LLVMSymbolizerPath, Args, nullptr, Redirects);
124 if (RunResult != 0)
125 return false;
126
127 // This report format is based on the sanitizer stack trace printer. See
128 // sanitizer_stacktrace_printer.cc in compiler-rt.
129 auto OutputBuf = MemoryBuffer::getFile(OutputFile.c_str());
130 if (!OutputBuf)
131 return false;
132 StringRef Output = OutputBuf.get()->getBuffer();
133 SmallVector<StringRef, 32> Lines;
134 Output.split(Lines, "\n");
135 auto CurLine = Lines.begin();
136 int frame_no = 0;
137 for (int i = 0; i < Depth; i++) {
138 if (!Modules[i]) {
139 OS << '#' << frame_no++ << ' ' << format_ptr(StackTrace[i]) << '\n';
140 continue;
141 }
142 // Read pairs of lines (function name and file/line info) until we
143 // encounter empty line.
144 for (;;) {
145 if (CurLine == Lines.end())
146 return false;
147 StringRef FunctionName = *CurLine++;
148 if (FunctionName.empty())
149 break;
150 OS << '#' << frame_no++ << ' ' << format_ptr(StackTrace[i]) << ' ';
151 if (!FunctionName.startswith("??"))
152 OS << FunctionName << ' ';
153 if (CurLine == Lines.end())
154 return false;
155 StringRef FileLineInfo = *CurLine++;
156 if (!FileLineInfo.startswith("??"))
157 OS << FileLineInfo;
158 else
159 OS << "(" << Modules[i] << '+' << format_hex(Offsets[i], 0) << ")";
160 OS << "\n";
161 }
162 }
163 return true;
164 }
165
166 // Include the platform-specific parts of this class.
167 #ifdef LLVM_ON_UNIX
168 #include "Unix/Signals.inc"
169 #endif
170 #ifdef LLVM_ON_WIN32
171 #include "Windows/Signals.inc"
172 #endif
173