Log.h revision 317027 
1//===-- Log.h ---------------------------------------------------*- 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#ifndef LLDB_UTILITY_LOG_H
11#define LLDB_UTILITY_LOG_H
12
13#include "lldb/Utility/Flags.h"
14#include "lldb/Utility/Logging.h"
15#include "lldb/lldb-defines.h"
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/StringMap.h" // for StringMap
19#include "llvm/ADT/StringRef.h" // for StringRef, StringLiteral
20#include "llvm/Support/FormatVariadic.h"
21#include "llvm/Support/RWMutex.h"
22
23#include <atomic>
24#include <cstdarg>
25#include <cstdint>
26#include <memory>      // for shared_ptr
27#include <string>      // for string
28#include <type_traits> // for forward
29
30namespace llvm {
31class raw_ostream;
32}
33namespace llvm {
34template <class C> class ManagedStatic;
35}
36//----------------------------------------------------------------------
37// Logging Options
38//----------------------------------------------------------------------
39#define LLDB_LOG_OPTION_THREADSAFE (1u << 0)
40#define LLDB_LOG_OPTION_VERBOSE (1u << 1)
41#define LLDB_LOG_OPTION_PREPEND_SEQUENCE (1u << 3)
42#define LLDB_LOG_OPTION_PREPEND_TIMESTAMP (1u << 4)
43#define LLDB_LOG_OPTION_PREPEND_PROC_AND_THREAD (1u << 5)
44#define LLDB_LOG_OPTION_PREPEND_THREAD_NAME (1U << 6)
45#define LLDB_LOG_OPTION_BACKTRACE (1U << 7)
46#define LLDB_LOG_OPTION_APPEND (1U << 8)
47#define LLDB_LOG_OPTION_PREPEND_FILE_FUNCTION (1U << 9)
48
49//----------------------------------------------------------------------
50// Logging Functions
51//----------------------------------------------------------------------
52namespace lldb_private {
53
54class Log final {
55public:
56  // Description of a log channel category.
57  struct Category {
58    llvm::StringLiteral name;
59    llvm::StringLiteral description;
60    uint32_t flag;
61  };
62
63  // This class describes a log channel. It also encapsulates the behavior
64  // necessary to enable a log channel in an atomic manner.
65  class Channel {
66    std::atomic<Log *> log_ptr;
67    friend class Log;
68
69  public:
70    const llvm::ArrayRef<Category> categories;
71    const uint32_t default_flags;
72
73    constexpr Channel(llvm::ArrayRef<Log::Category> categories,
74                      uint32_t default_flags)
75        : log_ptr(nullptr), categories(categories),
76          default_flags(default_flags) {}
77
78    // This function is safe to call at any time
79    // If the channel is disabled after (or concurrently with) this function
80    // returning a non-null Log pointer, it is still safe to attempt to write to
81    // the Log object -- the output will be discarded.
82    Log *GetLogIfAll(uint32_t mask) {
83      Log *log = log_ptr.load(std::memory_order_relaxed);
84      if (log && log->GetMask().AllSet(mask))
85        return log;
86      return nullptr;
87    }
88
89    // This function is safe to call at any time
90    // If the channel is disabled after (or concurrently with) this function
91    // returning a non-null Log pointer, it is still safe to attempt to write to
92    // the Log object -- the output will be discarded.
93    Log *GetLogIfAny(uint32_t mask) {
94      Log *log = log_ptr.load(std::memory_order_relaxed);
95      if (log && log->GetMask().AnySet(mask))
96        return log;
97      return nullptr;
98    }
99  };
100
101  //------------------------------------------------------------------
102  // Static accessors for logging channels
103  //------------------------------------------------------------------
104  static void Register(llvm::StringRef name, Channel &channel);
105  static void Unregister(llvm::StringRef name);
106
107  static bool
108  EnableLogChannel(const std::shared_ptr<llvm::raw_ostream> &log_stream_sp,
109                   uint32_t log_options, llvm::StringRef channel,
110                   llvm::ArrayRef<const char *> categories,
111                   llvm::raw_ostream &error_stream);
112
113  static bool DisableLogChannel(llvm::StringRef channel,
114                                llvm::ArrayRef<const char *> categories,
115                                llvm::raw_ostream &error_stream);
116
117  static bool ListChannelCategories(llvm::StringRef channel, llvm::raw_ostream &stream);
118
119  static void DisableAllLogChannels();
120
121  static void ListAllLogChannels(llvm::raw_ostream &stream);
122
123  //------------------------------------------------------------------
124  // Member functions
125  //
126  // These functions are safe to call at any time you have a Log* obtained from
127  // the Channel class. If logging is disabled between you obtaining the Log
128  // object and writing to it, the output will be silently discarded.
129  //------------------------------------------------------------------
130  Log(Channel &channel) : m_channel(channel) {}
131  ~Log() = default;
132
133  void PutCString(const char *cstr);
134  void PutString(llvm::StringRef str);
135
136  template <typename... Args>
137  void Format(llvm::StringRef file, llvm::StringRef function,
138              const char *format, Args &&... args) {
139    Format(file, function, llvm::formatv(format, std::forward<Args>(args)...));
140  }
141
142  void Printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
143
144  void VAPrintf(const char *format, va_list args);
145
146  void Error(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
147
148  void VAError(const char *format, va_list args);
149
150  void Verbose(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
151
152  void Warning(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
153
154  const Flags GetOptions() const;
155
156  const Flags GetMask() const;
157
158  bool GetVerbose() const;
159
160private:
161  Channel &m_channel;
162
163  // The mutex makes sure enable/disable operations are thread-safe. The options
164  // and mask variables are atomic to enable their reading in
165  // Channel::GetLogIfAny without taking the mutex to speed up the fast path.
166  // Their modification however, is still protected by this mutex.
167  llvm::sys::RWMutex m_mutex;
168
169  std::shared_ptr<llvm::raw_ostream> m_stream_sp;
170  std::atomic<uint32_t> m_options{0};
171  std::atomic<uint32_t> m_mask{0};
172
173  void WriteHeader(llvm::raw_ostream &OS, llvm::StringRef file,
174                   llvm::StringRef function);
175  void WriteMessage(const std::string &message);
176
177  void Format(llvm::StringRef file, llvm::StringRef function,
178              const llvm::formatv_object_base &payload);
179
180  std::shared_ptr<llvm::raw_ostream> GetStream() {
181    llvm::sys::ScopedReader lock(m_mutex);
182    return m_stream_sp;
183  }
184
185  void Enable(const std::shared_ptr<llvm::raw_ostream> &stream_sp,
186              uint32_t options, uint32_t flags);
187
188  void Disable(uint32_t flags);
189
190  typedef llvm::StringMap<Log> ChannelMap;
191  static llvm::ManagedStatic<ChannelMap> g_channel_map;
192
193  static void ListCategories(llvm::raw_ostream &stream,
194                             const ChannelMap::value_type &entry);
195  static uint32_t GetFlags(llvm::raw_ostream &stream, const ChannelMap::value_type &entry,
196                           llvm::ArrayRef<const char *> categories);
197
198  Log(const Log &) = delete;
199  void operator=(const Log &) = delete;
200};
201
202} // namespace lldb_private
203
204#define LLDB_LOG(log, ...)                                                     \
205  do {                                                                         \
206    ::lldb_private::Log *log_private = (log);                                  \
207    if (log_private)                                                           \
208      log_private->Format(__FILE__, __FUNCTION__, __VA_ARGS__);                \
209  } while (0)
210
211#define LLDB_LOGV(log, ...)                                                    \
212  do {                                                                         \
213    ::lldb_private::Log *log_private = (log);                                  \
214    if (log_private && log_private->GetVerbose())                              \
215      log_private->Format(__FILE__, __FUNCTION__, __VA_ARGS__);                \
216  } while (0)
217
218#endif // LLDB_UTILITY_LOG_H
219