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/Utility/Logging.h"
14#include "lldb/lldb-defines.h"
15
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/StringMap.h"
19#include "llvm/ADT/StringRef.h"
20#include "llvm/Support/Error.h"
21#include "llvm/Support/FormatVariadic.h"
22#include "llvm/Support/ManagedStatic.h"
23#include "llvm/Support/RWMutex.h"
24
25#include <atomic>
26#include <cstdarg>
27#include <cstdint>
28#include <memory>
29#include <string>
30#include <type_traits>
31
32namespace llvm {
33class raw_ostream;
34}
35// Logging Options
36#define LLDB_LOG_OPTION_THREADSAFE (1u << 0)
37#define LLDB_LOG_OPTION_VERBOSE (1u << 1)
38#define LLDB_LOG_OPTION_PREPEND_SEQUENCE (1u << 3)
39#define LLDB_LOG_OPTION_PREPEND_TIMESTAMP (1u << 4)
40#define LLDB_LOG_OPTION_PREPEND_PROC_AND_THREAD (1u << 5)
41#define LLDB_LOG_OPTION_PREPEND_THREAD_NAME (1U << 6)
42#define LLDB_LOG_OPTION_BACKTRACE (1U << 7)
43#define LLDB_LOG_OPTION_APPEND (1U << 8)
44#define LLDB_LOG_OPTION_PREPEND_FILE_FUNCTION (1U << 9)
45
46// Logging Functions
47namespace lldb_private {
48
49class Log final {
50public:
51 // Description of a log channel category.
52 struct Category {
53 llvm::StringLiteral name;
54 llvm::StringLiteral description;
55 uint32_t flag;
56 };
57
58 // This class describes a log channel. It also encapsulates the behavior
59 // necessary to enable a log channel in an atomic manner.
60 class Channel {
61 std::atomic<Log *> log_ptr;
62 friend class Log;
63
64 public:
65 const llvm::ArrayRef<Category> categories;
66 const uint32_t default_flags;
67
68 constexpr Channel(llvm::ArrayRef<Log::Category> categories,
69 uint32_t default_flags)
70 : log_ptr(nullptr), categories(categories),
71 default_flags(default_flags) {}
72
73 // This function is safe to call at any time. If the channel is disabled
74 // after (or concurrently with) this function returning a non-null Log
75 // pointer, it is still safe to attempt to write to the Log object -- the
76 // output will be discarded.
77 Log *GetLogIfAll(uint32_t mask) {
78 Log *log = log_ptr.load(std::memory_order_relaxed);
79 if (log && log->GetMask().AllSet(mask))
80 return log;
81 return nullptr;
82 }
83
84 // This function is safe to call at any time. If the channel is disabled
85 // after (or concurrently with) this function returning a non-null Log
86 // pointer, it is still safe to attempt to write to the Log object -- the
87 // output will be discarded.
88 Log *GetLogIfAny(uint32_t mask) {
89 Log *log = log_ptr.load(std::memory_order_relaxed);
90 if (log && log->GetMask().AnySet(mask))
91 return log;
92 return nullptr;
93 }
94 };
95
96
97 static void Initialize();
98
99 // Static accessors for logging channels
100 static void Register(llvm::StringRef name, Channel &channel);
101 static void Unregister(llvm::StringRef name);
102
103 static bool
104 EnableLogChannel(const std::shared_ptr<llvm::raw_ostream> &log_stream_sp,
105 uint32_t log_options, llvm::StringRef channel,
106 llvm::ArrayRef<const char *> categories,
107 llvm::raw_ostream &error_stream);
108
109 static bool DisableLogChannel(llvm::StringRef channel,
110 llvm::ArrayRef<const char *> categories,
111 llvm::raw_ostream &error_stream);
112
113 static bool ListChannelCategories(llvm::StringRef channel,
114 llvm::raw_ostream &stream);
115
116 /// Returns the list of log channels.
117 static std::vector<llvm::StringRef> ListChannels();
118 /// Calls the given lambda for every category in the given channel.
119 /// If no channel with the given name exists, lambda is never called.
120 static void ForEachChannelCategory(
121 llvm::StringRef channel,
122 llvm::function_ref<void(llvm::StringRef, llvm::StringRef)> lambda);
123
124 static void DisableAllLogChannels();
125
126 static void ListAllLogChannels(llvm::raw_ostream &stream);
127
128 // Member functions
129 //
130 // These functions are safe to call at any time you have a Log* obtained from
131 // the Channel class. If logging is disabled between you obtaining the Log
132 // object and writing to it, the output will be silently discarded.
133 Log(Channel &channel) : m_channel(channel) {}
134 ~Log() = default;
135
136 void PutCString(const char *cstr);
137 void PutString(llvm::StringRef str);
138
139 template <typename... Args>
140 void Format(llvm::StringRef file, llvm::StringRef function,
141 const char *format, Args &&... args) {
142 Format(file, function, llvm::formatv(format, std::forward<Args>(args)...));
143 }
144
145 template <typename... Args>
146 void FormatError(llvm::Error error, llvm::StringRef file,
147 llvm::StringRef function, const char *format,
148 Args &&... args) {
149 Format(file, function,
150 llvm::formatv(format, llvm::toString(std::move(error)),
151 std::forward<Args>(args)...));
152 }
153
154 /// Prefer using LLDB_LOGF whenever possible.
155 void Printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
156
157 void Error(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
158
159 void Verbose(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
160
161 void Warning(const char *fmt, ...) __attribute__((format(printf, 2, 3)));
162
163 const Flags GetOptions() const;
164
165 const Flags GetMask() const;
166
167 bool GetVerbose() const;
168
169 void VAPrintf(const char *format, va_list args);
170 void VAError(const char *format, va_list args);
171
172private:
173 Channel &m_channel;
174
175 // The mutex makes sure enable/disable operations are thread-safe. The
176 // options and mask variables are atomic to enable their reading in
177 // Channel::GetLogIfAny without taking the mutex to speed up the fast path.
178 // Their modification however, is still protected by this mutex.
179 llvm::sys::RWMutex m_mutex;
180
181 std::shared_ptr<llvm::raw_ostream> m_stream_sp;
182 std::atomic<uint32_t> m_options{0};
183 std::atomic<uint32_t> m_mask{0};
184
185 void WriteHeader(llvm::raw_ostream &OS, llvm::StringRef file,
186 llvm::StringRef function);
187 void WriteMessage(const std::string &message);
188
189 void Format(llvm::StringRef file, llvm::StringRef function,
190 const llvm::formatv_object_base &payload);
191
192 std::shared_ptr<llvm::raw_ostream> GetStream() {
193 llvm::sys::ScopedReader lock(m_mutex);
194 return m_stream_sp;
195 }
196
197 void Enable(const std::shared_ptr<llvm::raw_ostream> &stream_sp,
198 uint32_t options, uint32_t flags);
199
200 void Disable(uint32_t flags);
201
202 typedef llvm::StringMap<Log> ChannelMap;
203 static llvm::ManagedStatic<ChannelMap> g_channel_map;
204
205 static void ForEachCategory(
206 const Log::ChannelMap::value_type &entry,
207 llvm::function_ref<void(llvm::StringRef, llvm::StringRef)> lambda);
208
209 static void ListCategories(llvm::raw_ostream &stream,
210 const ChannelMap::value_type &entry);
211 static uint32_t GetFlags(llvm::raw_ostream &stream, const ChannelMap::value_type &entry,
212 llvm::ArrayRef<const char *> categories);
213
214 static void DisableLoggingChild();
215
216 Log(const Log &) = delete;
217 void operator=(const Log &) = delete;
218};
219
220} // namespace lldb_private
221
222/// The LLDB_LOG* macros defined below are the way to emit log messages.
223///
224/// Note that the macros surround the arguments in a check for the log
225/// being on, so you can freely call methods in arguments without affecting
226/// the non-log execution flow.
227///
228/// If you need to do more complex computations to prepare the log message
229/// be sure to add your own if (log) check, since we don't want logging to
230/// have any effect when not on.
231///
232/// However, the LLDB_LOG macro uses the llvm::formatv system (see the
233/// ProgrammersManual page in the llvm docs for more details). This allows
234/// the use of "format_providers" to auto-format datatypes, and there are
235/// already formatters for some of the llvm and lldb datatypes.
236///
237/// So if you need to do non-trivial formatting of one of these types, be
238/// sure to grep the lldb and llvm sources for "format_provider" to see if
239/// there is already a formatter before doing in situ formatting, and if
240/// possible add a provider if one does not already exist.
241
242#define LLDB_LOG(log, ...) \
243 do { \
244 ::lldb_private::Log *log_private = (log); \
245 if (log_private) \
246 log_private->Format(__FILE__, __func__, __VA_ARGS__); \
247 } while (0)
248
249#define LLDB_LOGF(log, ...) \
250 do { \
251 ::lldb_private::Log *log_private = (log); \
252 if (log_private) \
253 log_private->Printf(__VA_ARGS__); \
254 } while (0)
255
256#define LLDB_LOGV(log, ...) \
257 do { \
258 ::lldb_private::Log *log_private = (log); \
259 if (log_private && log_private->GetVerbose()) \
260 log_private->Format(__FILE__, __func__, __VA_ARGS__); \
261 } while (0)
262
263// Write message to log, if error is set. In the log message refer to the error
264// with {0}. Error is cleared regardless of whether logging is enabled.
265#define LLDB_LOG_ERROR(log, error, ...) \
266 do { \
267 ::lldb_private::Log *log_private = (log); \
268 ::llvm::Error error_private = (error); \
269 if (log_private && error_private) { \
270 log_private->FormatError(::std::move(error_private), __FILE__, __func__, \
271 __VA_ARGS__); \
272 } else \
273 ::llvm::consumeError(::std::move(error_private)); \
274 } while (0)
275
276#endif // LLDB_UTILITY_LOG_H
277