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Log.h
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1//===-- Log.h ---------------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLDB_UTILITY_LOG_H
10#define LLDB_UTILITY_LOG_H
11
12#include "lldb/Utility/Flags.h"
13#include "lldb/lldb-defines.h"
14
15#include "llvm/ADT/ArrayRef.h"
16#include "llvm/ADT/STLExtras.h"
17#include "llvm/ADT/StringMap.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/Error.h"
20#include "llvm/Support/FormatVariadic.h"
21#include "llvm/Support/ManagedStatic.h"
22#include "llvm/Support/RWMutex.h"
23
24#include <atomic>
25#include <cstdarg>
26#include <cstdint>
27#include <memory>
28#include <mutex>
29#include <string>
30#include <type_traits>
31
32namespace llvm {
33class raw_ostream;
34}
35// Logging Options
36#define LLDB_LOG_OPTION_VERBOSE (1u << 1)
37#define LLDB_LOG_OPTION_PREPEND_SEQUENCE (1u << 3)
38#define LLDB_LOG_OPTION_PREPEND_TIMESTAMP (1u << 4)
39#define LLDB_LOG_OPTION_PREPEND_PROC_AND_THREAD (1u << 5)
40#define LLDB_LOG_OPTION_PREPEND_THREAD_NAME (1U << 6)
41#define LLDB_LOG_OPTION_BACKTRACE (1U << 7)
42#define LLDB_LOG_OPTION_APPEND (1U << 8)
43#define LLDB_LOG_OPTION_PREPEND_FILE_FUNCTION (1U << 9)
44
45// Logging Functions
46namespace lldb_private {
47
49public:
50 virtual ~LogHandler() = default;
51 virtual void Emit(llvm::StringRef message) = 0;
52
53 virtual bool isA(const void *ClassID) const { return ClassID == &ID; }
54 static bool classof(const LogHandler *obj) { return obj->isA(&ID); }
55
56private:
57 static char ID;
58};
59
61public:
62 StreamLogHandler(int fd, bool should_close, size_t buffer_size = 0);
63 ~StreamLogHandler() override;
64
65 void Emit(llvm::StringRef message) override;
66 void Flush();
67
68 bool isA(const void *ClassID) const override { return ClassID == &ID; }
69 static bool classof(const LogHandler *obj) { return obj->isA(&ID); }
70
71private:
72 std::mutex m_mutex;
73 llvm::raw_fd_ostream m_stream;
74 static char ID;
75};
76
78public:
79 CallbackLogHandler(lldb::LogOutputCallback callback, void *baton);
80
81 void Emit(llvm::StringRef message) override;
82
83 bool isA(const void *ClassID) const override { return ClassID == &ID; }
84 static bool classof(const LogHandler *obj) { return obj->isA(&ID); }
85
86private:
88 void *m_baton;
89 static char ID;
90};
91
93public:
94 RotatingLogHandler(size_t size);
95
96 void Emit(llvm::StringRef message) override;
97 void Dump(llvm::raw_ostream &stream) const;
98
99 bool isA(const void *ClassID) const override { return ClassID == &ID; }
100 static bool classof(const LogHandler *obj) { return obj->isA(&ID); }
101
102private:
103 size_t NormalizeIndex(size_t i) const;
104 size_t GetNumMessages() const;
105 size_t GetFirstMessageIndex() const;
106
107 mutable std::mutex m_mutex;
108 std::unique_ptr<std::string[]> m_messages;
109 const size_t m_size = 0;
110 size_t m_next_index = 0;
111 size_t m_total_count = 0;
112 static char ID;
113};
114
115class Log final {
116public:
117 /// The underlying type of all log channel enums. Declare them as:
118 /// enum class MyLog : MaskType {
119 /// Channel0 = Log::ChannelFlag<0>,
120 /// Channel1 = Log::ChannelFlag<1>,
121 /// ...,
122 /// LLVM_MARK_AS_BITMASK_ENUM(LastChannel),
123 /// };
124 using MaskType = uint64_t;
125
126 template <MaskType Bit>
127 static constexpr MaskType ChannelFlag = MaskType(1) << Bit;
128
129 // Description of a log channel category.
130 struct Category {
131 llvm::StringLiteral name;
132 llvm::StringLiteral description;
134
135 template <typename Cat>
136 constexpr Category(llvm::StringLiteral name,
137 llvm::StringLiteral description, Cat mask)
139 static_assert(
140 std::is_same<Log::MaskType, std::underlying_type_t<Cat>>::value);
141 }
142 };
143
144 // This class describes a log channel. It also encapsulates the behavior
145 // necessary to enable a log channel in an atomic manner.
146 class Channel {
147 std::atomic<Log *> log_ptr;
148 friend class Log;
149
150 public:
151 const llvm::ArrayRef<Category> categories;
153
154 template <typename Cat>
155 constexpr Channel(llvm::ArrayRef<Log::Category> categories,
156 Cat default_flags)
157 : log_ptr(nullptr), categories(categories),
159 static_assert(
160 std::is_same<Log::MaskType, std::underlying_type_t<Cat>>::value);
161 }
162
163 // This function is safe to call at any time. If the channel is disabled
164 // after (or concurrently with) this function returning a non-null Log
165 // pointer, it is still safe to attempt to write to the Log object -- the
166 // output will be discarded.
168 Log *log = log_ptr.load(std::memory_order_relaxed);
169 if (log && ((log->GetMask() & mask) != 0))
170 return log;
171 return nullptr;
172 }
173 };
174
175
176 // Static accessors for logging channels
177 static void Register(llvm::StringRef name, Channel &channel);
178 static void Unregister(llvm::StringRef name);
179
180 static bool
181 EnableLogChannel(const std::shared_ptr<LogHandler> &log_handler_sp,
182 uint32_t log_options, llvm::StringRef channel,
183 llvm::ArrayRef<const char *> categories,
184 llvm::raw_ostream &error_stream);
185
186 static bool DisableLogChannel(llvm::StringRef channel,
187 llvm::ArrayRef<const char *> categories,
188 llvm::raw_ostream &error_stream);
189
190 static bool DumpLogChannel(llvm::StringRef channel,
191 llvm::raw_ostream &output_stream,
192 llvm::raw_ostream &error_stream);
193
194 static bool ListChannelCategories(llvm::StringRef channel,
195 llvm::raw_ostream &stream);
196
197 /// Returns the list of log channels.
198 static std::vector<llvm::StringRef> ListChannels();
199 /// Calls the given lambda for every category in the given channel.
200 /// If no channel with the given name exists, lambda is never called.
201 static void ForEachChannelCategory(
202 llvm::StringRef channel,
203 llvm::function_ref<void(llvm::StringRef, llvm::StringRef)> lambda);
204
205 static void DisableAllLogChannels();
206
207 static void ListAllLogChannels(llvm::raw_ostream &stream);
208
209 // Member functions
210 //
211 // These functions are safe to call at any time you have a Log* obtained from
212 // the Channel class. If logging is disabled between you obtaining the Log
213 // object and writing to it, the output will be silently discarded.
214 Log(Channel &channel) : m_channel(channel) {}
215 ~Log() = default;
216
217 void PutCString(const char *cstr);
218 void PutString(llvm::StringRef str);
219
220 template <typename... Args>
221 void Format(llvm::StringRef file, llvm::StringRef function,
222 const char *format, Args &&... args) {
223 Format(file, function, llvm::formatv(format, std::forward<Args>(args)...));
224 }
225
226 template <typename... Args>
227 void FormatError(llvm::Error error, llvm::StringRef file,
228 llvm::StringRef function, const char *format,
229 Args &&... args) {
230 Format(file, function,
231 llvm::formatv(format, llvm::toString(std::move(error)),
232 std::forward<Args>(args)...));
233 }
234
235 void Formatf(llvm::StringRef file, llvm::StringRef function,
236 const char *format, ...) __attribute__((format(printf, 4, 5)));
237
238 /// Prefer using LLDB_LOGF whenever possible.
239 void Printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
240
241 void Error(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
242
243 void Verbose(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
244
245 void Warning(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
246
247 const Flags GetOptions() const;
248
249 MaskType GetMask() const;
250
251 bool GetVerbose() const;
252
253 void VAPrintf(const char *format, va_list args);
254 void VAError(const char *format, va_list args);
255 void VAFormatf(llvm::StringRef file, llvm::StringRef function,
256 const char *format, va_list args);
257
258private:
260
261 // The mutex makes sure enable/disable operations are thread-safe. The
262 // options and mask variables are atomic to enable their reading in
263 // Channel::GetLogIfAny without taking the mutex to speed up the fast path.
264 // Their modification however, is still protected by this mutex.
265 llvm::sys::RWMutex m_mutex;
266
267 std::shared_ptr<LogHandler> m_handler;
268 std::atomic<uint32_t> m_options{0};
269 std::atomic<MaskType> m_mask{0};
270
271 void WriteHeader(llvm::raw_ostream &OS, llvm::StringRef file,
272 llvm::StringRef function);
273 void WriteMessage(llvm::StringRef message);
274
275 void Format(llvm::StringRef file, llvm::StringRef function,
276 const llvm::formatv_object_base &payload);
277
278 std::shared_ptr<LogHandler> GetHandler() {
279 llvm::sys::ScopedReader lock(m_mutex);
280 return m_handler;
281 }
282
283 void Enable(const std::shared_ptr<LogHandler> &handler_sp, uint32_t options,
284 MaskType flags);
285
286 void Disable(MaskType flags);
287
288 bool Dump(llvm::raw_ostream &stream);
289
290 typedef llvm::StringMap<Log> ChannelMap;
291 static llvm::ManagedStatic<ChannelMap> g_channel_map;
292
293 static void ForEachCategory(
294 const Log::ChannelMap::value_type &entry,
295 llvm::function_ref<void(llvm::StringRef, llvm::StringRef)> lambda);
296
297 static void ListCategories(llvm::raw_ostream &stream,
298 const ChannelMap::value_type &entry);
299 static Log::MaskType GetFlags(llvm::raw_ostream &stream,
300 const ChannelMap::value_type &entry,
301 llvm::ArrayRef<const char *> categories);
302
303 Log(const Log &) = delete;
304 void operator=(const Log &) = delete;
305};
306
307// Must be specialized for a particular log type.
308template <typename Cat> Log::Channel &LogChannelFor() = delete;
309
310/// Retrieve the Log object for the channel associated with the given log enum.
311///
312/// Returns a valid Log object if any of the provided categories are enabled.
313/// Otherwise, returns nullptr.
314template <typename Cat> Log *GetLog(Cat mask) {
315 static_assert(
316 std::is_same<Log::MaskType, std::underlying_type_t<Cat>>::value);
317 return LogChannelFor<Cat>().GetLog(Log::MaskType(mask));
318}
319
320} // namespace lldb_private
321
322/// The LLDB_LOG* macros defined below are the way to emit log messages.
323///
324/// Note that the macros surround the arguments in a check for the log
325/// being on, so you can freely call methods in arguments without affecting
326/// the non-log execution flow.
327///
328/// If you need to do more complex computations to prepare the log message
329/// be sure to add your own if (log) check, since we don't want logging to
330/// have any effect when not on.
331///
332/// However, the LLDB_LOG macro uses the llvm::formatv system (see the
333/// ProgrammersManual page in the llvm docs for more details). This allows
334/// the use of "format_providers" to auto-format datatypes, and there are
335/// already formatters for some of the llvm and lldb datatypes.
336///
337/// So if you need to do non-trivial formatting of one of these types, be
338/// sure to grep the lldb and llvm sources for "format_provider" to see if
339/// there is already a formatter before doing in situ formatting, and if
340/// possible add a provider if one does not already exist.
341
342#define LLDB_LOG(log, ...) \
343 do { \
344 ::lldb_private::Log *log_private = (log); \
345 if (log_private) \
346 log_private->Format(__FILE__, __func__, __VA_ARGS__); \
347 } while (0)
348
349#define LLDB_LOGF(log, ...) \
350 do { \
351 ::lldb_private::Log *log_private = (log); \
352 if (log_private) \
353 log_private->Formatf(__FILE__, __func__, __VA_ARGS__); \
354 } while (0)
355
356#define LLDB_LOGV(log, ...) \
357 do { \
358 ::lldb_private::Log *log_private = (log); \
359 if (log_private && log_private->GetVerbose()) \
360 log_private->Format(__FILE__, __func__, __VA_ARGS__); \
361 } while (0)
362
363// Write message to log, if error is set. In the log message refer to the error
364// with {0}. Error is cleared regardless of whether logging is enabled.
365#define LLDB_LOG_ERROR(log, error, ...) \
366 do { \
367 ::lldb_private::Log *log_private = (log); \
368 ::llvm::Error error_private = (error); \
369 if (log_private && error_private) { \
370 log_private->FormatError(::std::move(error_private), __FILE__, __func__, \
371 __VA_ARGS__); \
372 } else \
373 ::llvm::consumeError(::std::move(error_private)); \
374 } while (0)
375
376// Write message to the verbose log, if error is set. In the log
377// message refer to the error with {0}. Error is cleared regardless of
378// whether logging is enabled.
379#define LLDB_LOG_ERRORV(log, error, ...) \
380 do { \
381 ::lldb_private::Log *log_private = (log); \
382 ::llvm::Error error_private = (error); \
383 if (log_private && log_private->GetVerbose() && error_private) { \
384 log_private->FormatError(::std::move(error_private), __FILE__, __func__, \
385 __VA_ARGS__); \
386 } else \
387 ::llvm::consumeError(::std::move(error_private)); \
388 } while (0)
389
390#endif // LLDB_UTILITY_LOG_H
static llvm::raw_ostream & error(Stream &strm)
llvm::Error Error
A command line argument class.
Definition: Args.h:33
lldb::LogOutputCallback m_callback
Definition: Log.h:87
static bool classof(const LogHandler *obj)
Definition: Log.h:84
bool isA(const void *ClassID) const override
Definition: Log.h:83
void Emit(llvm::StringRef message) override
Definition: Log.cpp:406
A class to manage flags.
Definition: Flags.h:22
virtual void Emit(llvm::StringRef message)=0
virtual bool isA(const void *ClassID) const
Definition: Log.h:53
static bool classof(const LogHandler *obj)
Definition: Log.h:54
static char ID
Definition: Log.h:57
virtual ~LogHandler()=default
constexpr Channel(llvm::ArrayRef< Log::Category > categories, Cat default_flags)
Definition: Log.h:155
Log * GetLog(MaskType mask)
Definition: Log.h:167
const llvm::ArrayRef< Category > categories
Definition: Log.h:151
std::atomic< Log * > log_ptr
Definition: Log.h:147
const MaskType default_flags
Definition: Log.h:152
llvm::sys::RWMutex m_mutex
Definition: Log.h:265
static void ListCategories(llvm::raw_ostream &stream, const ChannelMap::value_type &entry)
Definition: Log.cpp:54
void Disable(MaskType flags)
Definition: Log.cpp:106
std::shared_ptr< LogHandler > m_handler
Definition: Log.h:267
void WriteMessage(llvm::StringRef message)
Definition: Log.cpp:361
void PutCString(const char *cstr)
Definition: Log.cpp:134
static void ForEachCategory(const Log::ChannelMap::value_type &entry, llvm::function_ref< void(llvm::StringRef, llvm::StringRef)> lambda)
Definition: Log.cpp:45
static constexpr MaskType ChannelFlag
Definition: Log.h:127
llvm::StringMap< Log > ChannelMap
Definition: Log.h:290
void Formatf(llvm::StringRef file, llvm::StringRef function, const char *format,...) __attribute__((format(printf
Definition: Log.cpp:158
uint64_t MaskType
The underlying type of all log channel enums.
Definition: Log.h:124
Log(const Log &)=delete
static bool DisableLogChannel(llvm::StringRef channel, llvm::ArrayRef< const char * > categories, llvm::raw_ostream &error_stream)
Definition: Log.cpp:239
static void Register(llvm::StringRef name, Channel &channel)
Definition: Log.cpp:210
static void ListAllLogChannels(llvm::raw_ostream &stream)
Definition: Log.cpp:303
void VAFormatf(llvm::StringRef file, llvm::StringRef function, const char *format, va_list args)
Definition: Log.cpp:166
void WriteHeader(llvm::raw_ostream &OS, llvm::StringRef file, llvm::StringRef function)
Definition: Log.cpp:317
static bool DumpLogChannel(llvm::StringRef channel, llvm::raw_ostream &output_stream, llvm::raw_ostream &error_stream)
Definition: Log.cpp:254
void VAPrintf(const char *format, va_list args)
Definition: Log.cpp:152
void FormatError(llvm::Error error, llvm::StringRef file, llvm::StringRef function, const char *format, Args &&... args)
Definition: Log.h:227
void Format(llvm::StringRef file, llvm::StringRef function, const char *format, Args &&... args)
Definition: Log.h:221
static llvm::ManagedStatic< ChannelMap > g_channel_map
Definition: Log.h:291
std::shared_ptr< LogHandler > GetHandler()
Definition: Log.h:278
Log(Channel &channel)
Definition: Log.h:214
void void void void void Warning(const char *fmt,...) __attribute__((format(printf
Definition: Log.cpp:200
std::atomic< MaskType > m_mask
Definition: Log.h:269
static void Unregister(llvm::StringRef name)
Definition: Log.cpp:216
static bool ListChannelCategories(llvm::StringRef channel, llvm::raw_ostream &stream)
Definition: Log.cpp:270
static void DisableAllLogChannels()
Definition: Log.cpp:281
static void ForEachChannelCategory(llvm::StringRef channel, llvm::function_ref< void(llvm::StringRef, llvm::StringRef)> lambda)
Calls the given lambda for every category in the given channel.
Definition: Log.cpp:286
void void void void void const Flags GetOptions() const
Definition: Log.cpp:126
static bool EnableLogChannel(const std::shared_ptr< LogHandler > &log_handler_sp, uint32_t log_options, llvm::StringRef channel, llvm::ArrayRef< const char * > categories, llvm::raw_ostream &error_stream)
Definition: Log.cpp:223
void operator=(const Log &)=delete
MaskType GetMask() const
Definition: Log.cpp:130
void VAError(const char *format, va_list args)
Definition: Log.cpp:181
static std::vector< llvm::StringRef > ListChannels()
Returns the list of log channels.
Definition: Log.cpp:296
void Enable(const std::shared_ptr< LogHandler > &handler_sp, uint32_t options, MaskType flags)
Definition: Log.cpp:94
static Log::MaskType GetFlags(llvm::raw_ostream &stream, const ChannelMap::value_type &entry, llvm::ArrayRef< const char * > categories)
Definition: Log.cpp:63
bool GetVerbose() const
Definition: Log.cpp:313
void PutString(llvm::StringRef str)
Definition: Log.cpp:136
bool Dump(llvm::raw_ostream &stream)
Definition: Log.cpp:116
void void Printf(const char *format,...) __attribute__((format(printf
Prefer using LLDB_LOGF whenever possible.
Definition: Log.cpp:145
void void void void Verbose(const char *fmt,...) __attribute__((format(printf
Definition: Log.cpp:189
std::atomic< uint32_t > m_options
Definition: Log.h:268
Channel & m_channel
Definition: Log.h:259
void Dump(llvm::raw_ostream &stream) const
Definition: Log.cpp:431
std::unique_ptr< std::string[]> m_messages
Definition: Log.h:108
bool isA(const void *ClassID) const override
Definition: Log.h:99
void Emit(llvm::StringRef message) override
Definition: Log.cpp:413
static bool classof(const LogHandler *obj)
Definition: Log.h:100
size_t NormalizeIndex(size_t i) const
Definition: Log.cpp:421
size_t GetNumMessages() const
Definition: Log.cpp:423
size_t GetFirstMessageIndex() const
Definition: Log.cpp:427
~StreamLogHandler() override
Definition: Log.cpp:386
llvm::raw_fd_ostream m_stream
Definition: Log.h:73
void Emit(llvm::StringRef message) override
Definition: Log.cpp:393
bool isA(const void *ClassID) const override
Definition: Log.h:68
static bool classof(const LogHandler *obj)
Definition: Log.h:69
A class that represents a running process on the host machine.
Definition: SBAttachInfo.h:14
Log * GetLog(Cat mask)
Retrieve the Log object for the channel associated with the given log enum.
Definition: Log.h:314
Log::Channel & LogChannelFor()=delete
void(* LogOutputCallback)(const char *, void *baton)
Definition: lldb-types.h:72
Definition: Debugger.h:53
llvm::StringLiteral name
Definition: Log.h:131
llvm::StringLiteral description
Definition: Log.h:132
constexpr Category(llvm::StringLiteral name, llvm::StringLiteral description, Cat mask)
Definition: Log.h:136