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1 // Copyright 2016 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_LIBPLATFORM_V8_TRACING_H_
6 #define V8_LIBPLATFORM_V8_TRACING_H_
7 
8 #include <fstream>
9 #include <memory>
10 #include <unordered_set>
11 #include <vector>
12 
13 #include "libplatform/libplatform-export.h"
14 #include "v8-platform.h"  // NOLINT(build/include)
15 
16 namespace v8 {
17 
18 namespace base {
19 class Mutex;
20 }  // namespace base
21 
22 namespace platform {
23 namespace tracing {
24 
25 const int kTraceMaxNumArgs = 2;
26 
27 class V8_PLATFORM_EXPORT TraceObject {
28  public:
29   union ArgValue {
30     bool as_bool;
31     uint64_t as_uint;
32     int64_t as_int;
33     double as_double;
34     const void* as_pointer;
35     const char* as_string;
36   };
37 
TraceObject()38   TraceObject() {}
39   ~TraceObject();
40   void Initialize(
41       char phase, const uint8_t* category_enabled_flag, const char* name,
42       const char* scope, uint64_t id, uint64_t bind_id, int num_args,
43       const char** arg_names, const uint8_t* arg_types,
44       const uint64_t* arg_values,
45       std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
46       unsigned int flags);
47   void UpdateDuration();
48   void InitializeForTesting(
49       char phase, const uint8_t* category_enabled_flag, const char* name,
50       const char* scope, uint64_t id, uint64_t bind_id, int num_args,
51       const char** arg_names, const uint8_t* arg_types,
52       const uint64_t* arg_values,
53       std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
54       unsigned int flags, int pid, int tid, int64_t ts, int64_t tts,
55       uint64_t duration, uint64_t cpu_duration);
56 
pid()57   int pid() const { return pid_; }
tid()58   int tid() const { return tid_; }
phase()59   char phase() const { return phase_; }
category_enabled_flag()60   const uint8_t* category_enabled_flag() const {
61     return category_enabled_flag_;
62   }
name()63   const char* name() const { return name_; }
scope()64   const char* scope() const { return scope_; }
id()65   uint64_t id() const { return id_; }
bind_id()66   uint64_t bind_id() const { return bind_id_; }
num_args()67   int num_args() const { return num_args_; }
arg_names()68   const char** arg_names() { return arg_names_; }
arg_types()69   uint8_t* arg_types() { return arg_types_; }
arg_values()70   ArgValue* arg_values() { return arg_values_; }
arg_convertables()71   std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables() {
72     return arg_convertables_;
73   }
flags()74   unsigned int flags() const { return flags_; }
ts()75   int64_t ts() { return ts_; }
tts()76   int64_t tts() { return tts_; }
duration()77   uint64_t duration() { return duration_; }
cpu_duration()78   uint64_t cpu_duration() { return cpu_duration_; }
79 
80  private:
81   int pid_;
82   int tid_;
83   char phase_;
84   const char* name_;
85   const char* scope_;
86   const uint8_t* category_enabled_flag_;
87   uint64_t id_;
88   uint64_t bind_id_;
89   int num_args_ = 0;
90   const char* arg_names_[kTraceMaxNumArgs];
91   uint8_t arg_types_[kTraceMaxNumArgs];
92   ArgValue arg_values_[kTraceMaxNumArgs];
93   std::unique_ptr<v8::ConvertableToTraceFormat>
94       arg_convertables_[kTraceMaxNumArgs];
95   char* parameter_copy_storage_ = nullptr;
96   unsigned int flags_;
97   int64_t ts_;
98   int64_t tts_;
99   uint64_t duration_;
100   uint64_t cpu_duration_;
101 
102   // Disallow copy and assign
103   TraceObject(const TraceObject&) = delete;
104   void operator=(const TraceObject&) = delete;
105 };
106 
107 class V8_PLATFORM_EXPORT TraceWriter {
108  public:
TraceWriter()109   TraceWriter() {}
~TraceWriter()110   virtual ~TraceWriter() {}
111   virtual void AppendTraceEvent(TraceObject* trace_event) = 0;
112   virtual void Flush() = 0;
113 
114   static TraceWriter* CreateJSONTraceWriter(std::ostream& stream);
115 
116  private:
117   // Disallow copy and assign
118   TraceWriter(const TraceWriter&) = delete;
119   void operator=(const TraceWriter&) = delete;
120 };
121 
122 class V8_PLATFORM_EXPORT TraceBufferChunk {
123  public:
124   explicit TraceBufferChunk(uint32_t seq);
125 
126   void Reset(uint32_t new_seq);
IsFull()127   bool IsFull() const { return next_free_ == kChunkSize; }
128   TraceObject* AddTraceEvent(size_t* event_index);
GetEventAt(size_t index)129   TraceObject* GetEventAt(size_t index) { return &chunk_[index]; }
130 
seq()131   uint32_t seq() const { return seq_; }
size()132   size_t size() const { return next_free_; }
133 
134   static const size_t kChunkSize = 64;
135 
136  private:
137   size_t next_free_ = 0;
138   TraceObject chunk_[kChunkSize];
139   uint32_t seq_;
140 
141   // Disallow copy and assign
142   TraceBufferChunk(const TraceBufferChunk&) = delete;
143   void operator=(const TraceBufferChunk&) = delete;
144 };
145 
146 class V8_PLATFORM_EXPORT TraceBuffer {
147  public:
TraceBuffer()148   TraceBuffer() {}
~TraceBuffer()149   virtual ~TraceBuffer() {}
150 
151   virtual TraceObject* AddTraceEvent(uint64_t* handle) = 0;
152   virtual TraceObject* GetEventByHandle(uint64_t handle) = 0;
153   virtual bool Flush() = 0;
154 
155   static const size_t kRingBufferChunks = 1024;
156 
157   static TraceBuffer* CreateTraceBufferRingBuffer(size_t max_chunks,
158                                                   TraceWriter* trace_writer);
159 
160  private:
161   // Disallow copy and assign
162   TraceBuffer(const TraceBuffer&) = delete;
163   void operator=(const TraceBuffer&) = delete;
164 };
165 
166 // Options determines how the trace buffer stores data.
167 enum TraceRecordMode {
168   // Record until the trace buffer is full.
169   RECORD_UNTIL_FULL,
170 
171   // Record until the user ends the trace. The trace buffer is a fixed size
172   // and we use it as a ring buffer during recording.
173   RECORD_CONTINUOUSLY,
174 
175   // Record until the trace buffer is full, but with a huge buffer size.
176   RECORD_AS_MUCH_AS_POSSIBLE,
177 
178   // Echo to console. Events are discarded.
179   ECHO_TO_CONSOLE,
180 };
181 
182 class V8_PLATFORM_EXPORT TraceConfig {
183  public:
184   typedef std::vector<std::string> StringList;
185 
186   static TraceConfig* CreateDefaultTraceConfig();
187 
TraceConfig()188   TraceConfig() : enable_systrace_(false), enable_argument_filter_(false) {}
GetTraceRecordMode()189   TraceRecordMode GetTraceRecordMode() const { return record_mode_; }
IsSystraceEnabled()190   bool IsSystraceEnabled() const { return enable_systrace_; }
IsArgumentFilterEnabled()191   bool IsArgumentFilterEnabled() const { return enable_argument_filter_; }
192 
SetTraceRecordMode(TraceRecordMode mode)193   void SetTraceRecordMode(TraceRecordMode mode) { record_mode_ = mode; }
EnableSystrace()194   void EnableSystrace() { enable_systrace_ = true; }
EnableArgumentFilter()195   void EnableArgumentFilter() { enable_argument_filter_ = true; }
196 
197   void AddIncludedCategory(const char* included_category);
198 
199   bool IsCategoryGroupEnabled(const char* category_group) const;
200 
201  private:
202   TraceRecordMode record_mode_;
203   bool enable_systrace_ : 1;
204   bool enable_argument_filter_ : 1;
205   StringList included_categories_;
206 
207   // Disallow copy and assign
208   TraceConfig(const TraceConfig&) = delete;
209   void operator=(const TraceConfig&) = delete;
210 };
211 
212 class V8_PLATFORM_EXPORT TracingController {
213  public:
214   enum Mode { DISABLED = 0, RECORDING_MODE };
215 
216   // The pointer returned from GetCategoryGroupEnabledInternal() points to a
217   // value with zero or more of the following bits. Used in this class only.
218   // The TRACE_EVENT macros should only use the value as a bool.
219   // These values must be in sync with macro values in TraceEvent.h in Blink.
220   enum CategoryGroupEnabledFlags {
221     // Category group enabled for the recording mode.
222     ENABLED_FOR_RECORDING = 1 << 0,
223     // Category group enabled by SetEventCallbackEnabled().
224     ENABLED_FOR_EVENT_CALLBACK = 1 << 2,
225     // Category group enabled to export events to ETW.
226     ENABLED_FOR_ETW_EXPORT = 1 << 3
227   };
228 
229   TracingController();
230   ~TracingController();
231   void Initialize(TraceBuffer* trace_buffer);
232   const uint8_t* GetCategoryGroupEnabled(const char* category_group);
233   static const char* GetCategoryGroupName(const uint8_t* category_enabled_flag);
234   uint64_t AddTraceEvent(
235       char phase, const uint8_t* category_enabled_flag, const char* name,
236       const char* scope, uint64_t id, uint64_t bind_id, int32_t num_args,
237       const char** arg_names, const uint8_t* arg_types,
238       const uint64_t* arg_values,
239       std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
240       unsigned int flags);
241   void UpdateTraceEventDuration(const uint8_t* category_enabled_flag,
242                                 const char* name, uint64_t handle);
243 
244   void StartTracing(TraceConfig* trace_config);
245   void StopTracing();
246 
247   void AddTraceStateObserver(Platform::TraceStateObserver* observer);
248   void RemoveTraceStateObserver(Platform::TraceStateObserver* observer);
249 
250  private:
251   const uint8_t* GetCategoryGroupEnabledInternal(const char* category_group);
252   void UpdateCategoryGroupEnabledFlag(size_t category_index);
253   void UpdateCategoryGroupEnabledFlags();
254 
255   std::unique_ptr<TraceBuffer> trace_buffer_;
256   std::unique_ptr<TraceConfig> trace_config_;
257   std::unique_ptr<base::Mutex> mutex_;
258   std::unordered_set<Platform::TraceStateObserver*> observers_;
259   Mode mode_ = DISABLED;
260 
261   // Disallow copy and assign
262   TracingController(const TracingController&) = delete;
263   void operator=(const TracingController&) = delete;
264 };
265 
266 }  // namespace tracing
267 }  // namespace platform
268 }  // namespace v8
269 
270 #endif  // V8_LIBPLATFORM_V8_TRACING_H_
271