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1 // Copyright (c) 2014 Google Inc.
2 //
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 
6 // This header file defines implementation details of how the trace macros in
7 // SkTraceEventCommon.h collect and store trace events. Anything not
8 // implementation-specific should go in SkTraceEventCommon.h instead of here.
9 
10 #ifndef SkTraceEvent_DEFINED
11 #define SkTraceEvent_DEFINED
12 
13 #include "include/utils/SkEventTracer.h"
14 #include "src/core/SkTraceEventCommon.h"
15 #include <atomic>
16 
17 #if defined(SK_ANDROID_FRAMEWORK_USE_PERFETTO)
18     #include <string>
19     #include <utility>
20 #endif
21 
22 ////////////////////////////////////////////////////////////////////////////////
23 // Implementation specific tracing API definitions.
24 
25 // Makes it easier to add traces with a simple TRACE_EVENT0("skia", TRACE_FUNC).
26 #if defined(_MSC_VER)
27     #define TRACE_FUNC __FUNCSIG__
28 #else
29     #define TRACE_FUNC __PRETTY_FUNCTION__
30 #endif
31 
32 
33 #if defined(SK_ANDROID_FRAMEWORK_USE_PERFETTO)
34     // By default, const char* argument values are assumed to have long-lived scope
35     // and will not be copied. Use this macro to force a const char* to be copied.
36     //
37     // TRACE_STR_COPY should be used with short-lived strings that should be copied immediately.
38     // TRACE_STR_STATIC should be used with pointers to string literals with process lifetime.
39     // Neither should be used for string literals known at compile time.
40     //
41     // E.g. TRACE_EVENT0("skia", TRACE_STR_COPY(something.c_str()));
42     #define TRACE_STR_COPY(str) (::perfetto::DynamicString{str})
43 
44     // Allows callers to pass static strings that aren't known at compile time to trace functions.
45     //
46     // TRACE_STR_COPY should be used with short-lived strings that should be copied immediately.
47     // TRACE_STR_STATIC should be used with pointers to string literals with process lifetime.
48     // Neither should be used for string literals known at compile time.
49     //
50     // E.g. TRACE_EVENT0("skia", TRACE_STR_STATIC(this->name()));
51     // No-op when Perfetto is disabled, or outside of Android framework.
52     #define TRACE_STR_STATIC(str) (::perfetto::StaticString{str})
53 #else // !SK_ANDROID_FRAMEWORK_USE_PERFETTO
54     // By default, const char* argument values are assumed to have long-lived scope
55     // and will not be copied. Use this macro to force a const char* to be copied.
56     //
57     // TRACE_STR_COPY should be used with short-lived strings that should be copied immediately.
58     // TRACE_STR_STATIC should be used with pointers to string literals with process lifetime.
59     // Neither should be used for string literals known at compile time.
60     //
61     // E.g. TRACE_EVENT0("skia", TRACE_STR_COPY(something.c_str()));
62     #define TRACE_STR_COPY(str) (::skia_private::TraceStringWithCopy(str))
63 
64     // Allows callers to pass static strings that aren't known at compile time to trace functions.
65     //
66     // TRACE_STR_COPY should be used with short-lived strings that should be copied immediately.
67     // TRACE_STR_STATIC should be used with pointers to string literals with process lifetime.
68     // Neither should be used for string literals known at compile time.
69     //
70     // E.g. TRACE_EVENT0("skia", TRACE_STR_STATIC(this->name()));
71     // No-op when Perfetto is disabled, or outside of Android framework.
72     #define TRACE_STR_STATIC(str) (str)
73 #endif // SK_ANDROID_FRAMEWORK_USE_PERFETTO
74 
75 #define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() \
76     *INTERNAL_TRACE_EVENT_UID(category_group_enabled) & \
77         (SkEventTracer::kEnabledForRecording_CategoryGroupEnabledFlags | \
78          SkEventTracer::kEnabledForEventCallback_CategoryGroupEnabledFlags)
79 
80 // Get a pointer to the enabled state of the given trace category. Only
81 // long-lived literal strings should be given as the category group. The
82 // returned pointer can be held permanently in a local static for example. If
83 // the unsigned char is non-zero, tracing is enabled. If tracing is enabled,
84 // TRACE_EVENT_API_ADD_TRACE_EVENT can be called. It's OK if tracing is disabled
85 // between the load of the tracing state and the call to
86 // TRACE_EVENT_API_ADD_TRACE_EVENT, because this flag only provides an early out
87 // for best performance when tracing is disabled.
88 // const uint8_t*
89 //     TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(const char* category_group)
90 #define TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED \
91     SkEventTracer::GetInstance()->getCategoryGroupEnabled
92 
93 // Add a trace event to the platform tracing system.
94 // SkEventTracer::Handle TRACE_EVENT_API_ADD_TRACE_EVENT(
95 //                    char phase,
96 //                    const uint8_t* category_group_enabled,
97 //                    const char* name,
98 //                    uint64_t id,
99 //                    int num_args,
100 //                    const char** arg_names,
101 //                    const uint8_t* arg_types,
102 //                    const uint64_t* arg_values,
103 //                    unsigned char flags)
104 #define TRACE_EVENT_API_ADD_TRACE_EVENT \
105     SkEventTracer::GetInstance()->addTraceEvent
106 
107 // Set the duration field of a COMPLETE trace event.
108 // void TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
109 //     const uint8_t* category_group_enabled,
110 //     const char* name,
111 //     SkEventTracer::Handle id)
112 #define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
113     SkEventTracer::GetInstance()->updateTraceEventDuration
114 
115 #ifdef SK_ANDROID_FRAMEWORK_USE_PERFETTO
116     #define TRACE_EVENT_API_NEW_TRACE_SECTION(...) do {} while (0)
117 #else
118     // Start writing to a new trace output section (file, etc.).
119     // Accepts a label for the new section.
120     // void TRACE_EVENT_API_NEW_TRACE_SECTION(const char* name)
121     #define TRACE_EVENT_API_NEW_TRACE_SECTION \
122         SkEventTracer::GetInstance()->newTracingSection
123 #endif
124 
125 // Defines visibility for classes in trace_event.h
126 #define TRACE_EVENT_API_CLASS_EXPORT SK_API
127 
128 // We prepend this string to all category names, so that ALL Skia trace events are
129 // disabled by default when tracing in Chrome.
130 #define TRACE_CATEGORY_PREFIX "disabled-by-default-"
131 
132 ////////////////////////////////////////////////////////////////////////////////
133 
134 // Implementation detail: trace event macros create temporary variables
135 // to keep instrumentation overhead low. These macros give each temporary
136 // variable a unique name based on the line number to prevent name collisions.
137 #define INTERNAL_TRACE_EVENT_UID3(a,b) \
138     trace_event_unique_##a##b
139 #define INTERNAL_TRACE_EVENT_UID2(a,b) \
140     INTERNAL_TRACE_EVENT_UID3(a,b)
141 #define INTERNAL_TRACE_EVENT_UID(name_prefix) \
142     INTERNAL_TRACE_EVENT_UID2(name_prefix, __LINE__)
143 
144 // Implementation detail: internal macro to create static category.
145 // No barriers are needed, because this code is designed to operate safely
146 // even when the unsigned char* points to garbage data (which may be the case
147 // on processors without cache coherency).
148 #define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
149     category_group, atomic, category_group_enabled) \
150     category_group_enabled = \
151         reinterpret_cast<const uint8_t*>(atomic.load(std::memory_order_relaxed)); \
152     if (!category_group_enabled) { \
153       category_group_enabled = TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group); \
154       atomic.store(reinterpret_cast<intptr_t>(category_group_enabled), \
155                    std::memory_order_relaxed); \
156     }
157 
158 #define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group) \
159     static std::atomic<intptr_t> INTERNAL_TRACE_EVENT_UID(atomic){0}; \
160     const uint8_t* INTERNAL_TRACE_EVENT_UID(category_group_enabled); \
161     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
162         TRACE_CATEGORY_PREFIX category_group, \
163         INTERNAL_TRACE_EVENT_UID(atomic), \
164         INTERNAL_TRACE_EVENT_UID(category_group_enabled));
165 
166 // Implementation detail: internal macro to create static category and add
167 // event if the category is enabled.
168 #define INTERNAL_TRACE_EVENT_ADD(phase, category_group, name, flags, ...) \
169     do { \
170       INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
171       if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
172         skia_private::AddTraceEvent( \
173             phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
174             skia_private::kNoEventId, flags, ##__VA_ARGS__); \
175       } \
176     } while (0)
177 
178 // Implementation detail: internal macro to create static category and add
179 // event if the category is enabled.
180 #define INTERNAL_TRACE_EVENT_ADD_WITH_ID(phase, category_group, name, id, \
181                                          flags, ...) \
182     do { \
183       INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
184       if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
185         unsigned char trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID; \
186         skia_private::TraceID trace_event_trace_id( \
187             id, &trace_event_flags); \
188         skia_private::AddTraceEvent( \
189             phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
190             name, trace_event_trace_id.data(), trace_event_flags, \
191             ##__VA_ARGS__); \
192       } \
193     } while (0)
194 
195 // Implementation detail: internal macro to create static category and add begin
196 // event if the category is enabled. Also adds the end event when the scope
197 // ends.
198 #define INTERNAL_TRACE_EVENT_ADD_SCOPED(category_group, name, ...) \
199     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
200     skia_private::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
201     do { \
202         if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
203           SkEventTracer::Handle h = skia_private::AddTraceEvent( \
204               TRACE_EVENT_PHASE_COMPLETE, \
205               INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
206               name, skia_private::kNoEventId, \
207               TRACE_EVENT_FLAG_NONE, ##__VA_ARGS__); \
208           INTERNAL_TRACE_EVENT_UID(tracer).Initialize( \
209               INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, h); \
210         } \
211     } while (0)
212 
213 namespace skia_private {
214 
215 // Specify these values when the corresponding argument of AddTraceEvent is not
216 // used.
217 const int kZeroNumArgs = 0;
218 const uint64_t kNoEventId = 0;
219 
220 // TraceID encapsulates an ID that can either be an integer or pointer. Pointers
221 // are by default mangled with the Process ID so that they are unlikely to
222 // collide when the same pointer is used on different processes.
223 class TraceID {
224 public:
TraceID(const void * id,unsigned char * flags)225     TraceID(const void* id, unsigned char* flags)
226             : data_(static_cast<uint64_t>(reinterpret_cast<uintptr_t>(id))) {
227         *flags |= TRACE_EVENT_FLAG_MANGLE_ID;
228     }
TraceID(uint64_t id,unsigned char * flags)229     TraceID(uint64_t id, unsigned char* flags)
230         : data_(id) { (void)flags; }
TraceID(unsigned int id,unsigned char * flags)231     TraceID(unsigned int id, unsigned char* flags)
232         : data_(id) { (void)flags; }
TraceID(unsigned short id,unsigned char * flags)233     TraceID(unsigned short id, unsigned char* flags)
234         : data_(id) { (void)flags; }
TraceID(unsigned char id,unsigned char * flags)235     TraceID(unsigned char id, unsigned char* flags)
236         : data_(id) { (void)flags; }
TraceID(long long id,unsigned char * flags)237     TraceID(long long id, unsigned char* flags)
238         : data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(long id,unsigned char * flags)239     TraceID(long id, unsigned char* flags)
240         : data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(int id,unsigned char * flags)241     TraceID(int id, unsigned char* flags)
242         : data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(short id,unsigned char * flags)243     TraceID(short id, unsigned char* flags)
244         : data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(signed char id,unsigned char * flags)245     TraceID(signed char id, unsigned char* flags)
246         : data_(static_cast<uint64_t>(id)) { (void)flags; }
247 
data()248     uint64_t data() const { return data_; }
249 
250 private:
251     uint64_t data_;
252 };
253 
254 // Simple union to store various types as uint64_t.
255 union TraceValueUnion {
256   bool as_bool;
257   uint64_t as_uint;
258   long long as_int;
259   double as_double;
260   const void* as_pointer;
261   const char* as_string;
262 };
263 
264 // Simple container for const char* that should be copied instead of retained.
265 class TraceStringWithCopy {
266  public:
TraceStringWithCopy(const char * str)267   explicit TraceStringWithCopy(const char* str) : str_(str) {}
268   operator const char* () const { return str_; }
269  private:
270   const char* str_;
271 };
272 
273 // Define SetTraceValue for each allowed type. It stores the type and
274 // value in the return arguments. This allows this API to avoid declaring any
275 // structures so that it is portable to third_party libraries.
276 #define INTERNAL_DECLARE_SET_TRACE_VALUE(actual_type, \
277                                          union_member, \
278                                          value_type_id) \
279     static inline void SetTraceValue( \
280         actual_type arg, \
281         unsigned char* type, \
282         uint64_t* value) { \
283       TraceValueUnion type_value; \
284       type_value.union_member = arg; \
285       *type = value_type_id; \
286       *value = type_value.as_uint; \
287     }
288 // Simpler form for int types that can be safely casted.
289 #define INTERNAL_DECLARE_SET_TRACE_VALUE_INT(actual_type, \
290                                              value_type_id) \
291     static inline void SetTraceValue( \
292         actual_type arg, \
293         unsigned char* type, \
294         uint64_t* value) { \
295       *type = value_type_id; \
296       *value = static_cast<uint64_t>(arg); \
297     }
298 
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(uint64_t,TRACE_VALUE_TYPE_UINT)299 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(uint64_t, TRACE_VALUE_TYPE_UINT)
300 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned int, TRACE_VALUE_TYPE_UINT)
301 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned short, TRACE_VALUE_TYPE_UINT)
302 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned char, TRACE_VALUE_TYPE_UINT)
303 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long long, TRACE_VALUE_TYPE_INT)
304 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long, TRACE_VALUE_TYPE_INT)
305 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int, TRACE_VALUE_TYPE_INT)
306 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(short, TRACE_VALUE_TYPE_INT)
307 INTERNAL_DECLARE_SET_TRACE_VALUE_INT(signed char, TRACE_VALUE_TYPE_INT)
308 INTERNAL_DECLARE_SET_TRACE_VALUE(bool, as_bool, TRACE_VALUE_TYPE_BOOL)
309 INTERNAL_DECLARE_SET_TRACE_VALUE(double, as_double, TRACE_VALUE_TYPE_DOUBLE)
310 INTERNAL_DECLARE_SET_TRACE_VALUE(const void*, as_pointer, TRACE_VALUE_TYPE_POINTER)
311 INTERNAL_DECLARE_SET_TRACE_VALUE(const char*, as_string, TRACE_VALUE_TYPE_STRING)
312 INTERNAL_DECLARE_SET_TRACE_VALUE(const TraceStringWithCopy&, as_string,
313                                  TRACE_VALUE_TYPE_COPY_STRING)
314 
315 #undef INTERNAL_DECLARE_SET_TRACE_VALUE
316 #undef INTERNAL_DECLARE_SET_TRACE_VALUE_INT
317 
318 // These AddTraceEvent and AddTraceEvent template
319 // functions are defined here instead of in the macro, because the arg_values
320 // could be temporary objects, such as std::string. In order to store
321 // pointers to the internal c_str and pass through to the tracing API,
322 // the arg_values must live throughout these procedures.
323 
324 static inline SkEventTracer::Handle
325 AddTraceEvent(
326     char phase,
327     const uint8_t* category_group_enabled,
328     const char* name,
329     uint64_t id,
330     unsigned char flags) {
331   return TRACE_EVENT_API_ADD_TRACE_EVENT(
332       phase, category_group_enabled, name, id,
333       kZeroNumArgs, nullptr, nullptr, nullptr, flags);
334 }
335 
336 template<class ARG1_TYPE>
337 static inline SkEventTracer::Handle
AddTraceEvent(char phase,const uint8_t * category_group_enabled,const char * name,uint64_t id,unsigned char flags,const char * arg1_name,const ARG1_TYPE & arg1_val)338 AddTraceEvent(
339     char phase,
340     const uint8_t* category_group_enabled,
341     const char* name,
342     uint64_t id,
343     unsigned char flags,
344     const char* arg1_name,
345     const ARG1_TYPE& arg1_val) {
346   const int num_args = 1;
347   uint8_t arg_types[1];
348   uint64_t arg_values[1];
349   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
350   return TRACE_EVENT_API_ADD_TRACE_EVENT(
351       phase, category_group_enabled, name, id,
352       num_args, &arg1_name, arg_types, arg_values, flags);
353 }
354 
355 template<class ARG1_TYPE, class ARG2_TYPE>
356 static inline SkEventTracer::Handle
AddTraceEvent(char phase,const uint8_t * category_group_enabled,const char * name,uint64_t id,unsigned char flags,const char * arg1_name,const ARG1_TYPE & arg1_val,const char * arg2_name,const ARG2_TYPE & arg2_val)357 AddTraceEvent(
358     char phase,
359     const uint8_t* category_group_enabled,
360     const char* name,
361     uint64_t id,
362     unsigned char flags,
363     const char* arg1_name,
364     const ARG1_TYPE& arg1_val,
365     const char* arg2_name,
366     const ARG2_TYPE& arg2_val) {
367   const int num_args = 2;
368   const char* arg_names[2] = { arg1_name, arg2_name };
369   unsigned char arg_types[2];
370   uint64_t arg_values[2];
371   SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
372   SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
373   return TRACE_EVENT_API_ADD_TRACE_EVENT(
374       phase, category_group_enabled, name, id,
375       num_args, arg_names, arg_types, arg_values, flags);
376 }
377 
378 // Used by TRACE_EVENTx macros. Do not use directly.
379 class TRACE_EVENT_API_CLASS_EXPORT ScopedTracer {
380  public:
381   // Note: members of data_ intentionally left uninitialized. See Initialize.
ScopedTracer()382   ScopedTracer() : p_data_(nullptr) {}
383 
~ScopedTracer()384   ~ScopedTracer() {
385     if (p_data_ && *data_.category_group_enabled)
386       TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
387           data_.category_group_enabled, data_.name, data_.event_handle);
388   }
389 
Initialize(const uint8_t * category_group_enabled,const char * name,SkEventTracer::Handle event_handle)390   void Initialize(const uint8_t* category_group_enabled,
391                   const char* name,
392                   SkEventTracer::Handle event_handle) {
393     data_.category_group_enabled = category_group_enabled;
394     data_.name = name;
395     data_.event_handle = event_handle;
396     p_data_ = &data_;
397   }
398 
399  private:
400     ScopedTracer(const ScopedTracer&) = delete;
401     ScopedTracer& operator=(const ScopedTracer&) = delete;
402 
403   // This Data struct workaround is to avoid initializing all the members
404   // in Data during construction of this object, since this object is always
405   // constructed, even when tracing is disabled. If the members of Data were
406   // members of this class instead, compiler warnings occur about potential
407   // uninitialized accesses.
408   struct Data {
409     const uint8_t* category_group_enabled;
410     const char* name;
411     SkEventTracer::Handle event_handle;
412   };
413   Data* p_data_;
414   Data data_;
415 };
416 
417 }  // namespace skia_private
418 
419 #endif
420