1 /* 2 * Copyright (C) 2019 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef INCLUDE_PERFETTO_TRACING_INTERNAL_TRACK_EVENT_MACROS_H_ 18 #define INCLUDE_PERFETTO_TRACING_INTERNAL_TRACK_EVENT_MACROS_H_ 19 20 // This file contains underlying macros for the trace point track event 21 // implementation. Perfetto API users typically don't need to use anything here 22 // directly. 23 24 #include "perfetto/base/compiler.h" 25 #include "perfetto/tracing/internal/track_event_data_source.h" 26 #include "perfetto/tracing/string_helpers.h" 27 #include "perfetto/tracing/track_event_category_registry.h" 28 29 // Ignore GCC warning about a missing argument for a variadic macro parameter. 30 #if defined(__GNUC__) || defined(__clang__) 31 #pragma GCC system_header 32 #endif 33 34 // Defines data structures for backing a category registry. 35 // 36 // Each category has one enabled/disabled bit per possible data source instance. 37 // The bits are packed, i.e., each byte holds the state for instances. To 38 // improve cache locality, the bits for each instance are stored separately from 39 // the names of the categories: 40 // 41 // byte 0 byte 1 42 // (inst0, inst1, ..., inst7), (inst0, inst1, ..., inst7) 43 // 44 #define PERFETTO_INTERNAL_DECLARE_CATEGORIES(attrs, ...) \ 45 namespace internal { \ 46 constexpr ::perfetto::Category kCategories[] = {__VA_ARGS__}; \ 47 constexpr size_t kCategoryCount = \ 48 sizeof(kCategories) / sizeof(kCategories[0]); \ 49 /* The per-instance enable/disable state per category */ \ 50 attrs extern std::atomic<uint8_t> g_category_state_storage[kCategoryCount]; \ 51 /* The category registry which mediates access to the above structures. */ \ 52 /* The registry is used for two purposes: */ \ 53 /**/ \ 54 /* 1) For looking up categories at build (constexpr) time. */ \ 55 /* 2) For declaring the per-namespace TrackEvent data source. */ \ 56 /**/ \ 57 /* Because usage #1 requires a constexpr type and usage #2 requires an */ \ 58 /* extern type (to avoid declaring a type based on a translation-unit */ \ 59 /* variable), we need two separate copies of the registry with different */ \ 60 /* storage specifiers. */ \ 61 /**/ \ 62 /* Note that because of a Clang/Windows bug, the constexpr category */ \ 63 /* registry isn't given the enabled/disabled state array. All access */ \ 64 /* to the category states should therefore be done through the */ \ 65 /* non-constexpr registry. See */ \ 66 /* https://bugs.llvm.org/show_bug.cgi?id=51558 */ \ 67 /**/ \ 68 /* TODO(skyostil): Unify these using a C++17 inline constexpr variable. */ \ 69 constexpr ::perfetto::internal::TrackEventCategoryRegistry \ 70 kConstExprCategoryRegistry(kCategoryCount, &kCategories[0], nullptr); \ 71 attrs extern const ::perfetto::internal::TrackEventCategoryRegistry \ 72 kCategoryRegistry; \ 73 static_assert(kConstExprCategoryRegistry.ValidateCategories(), \ 74 "Invalid category names found"); \ 75 } // namespace internal 76 77 // In a .cc file, declares storage for each category's runtime state. 78 #define PERFETTO_INTERNAL_CATEGORY_STORAGE(attrs) \ 79 namespace internal { \ 80 attrs std::atomic<uint8_t> g_category_state_storage[kCategoryCount]; \ 81 attrs const ::perfetto::internal::TrackEventCategoryRegistry \ 82 kCategoryRegistry(kCategoryCount, \ 83 &kCategories[0], \ 84 &g_category_state_storage[0]); \ 85 } // namespace internal 86 87 // Defines the TrackEvent data source for the current track event namespace. 88 // `virtual ~TrackEvent` is added to avoid `-Wweak-vtables` warning. 89 // Learn more : aosp/2019906 90 #define PERFETTO_INTERNAL_DECLARE_TRACK_EVENT_DATA_SOURCE(attrs) \ 91 struct attrs TrackEvent : public ::perfetto::internal::TrackEventDataSource< \ 92 TrackEvent, &internal::kCategoryRegistry> { \ 93 virtual ~TrackEvent(); \ 94 } 95 96 #define PERFETTO_INTERNAL_DEFINE_TRACK_EVENT_DATA_SOURCE() \ 97 TrackEvent::~TrackEvent() = default; 98 99 // At compile time, turns a category name represented by a static string into an 100 // index into the current category registry. A build error will be generated if 101 // the category hasn't been registered or added to the list of allowed dynamic 102 // categories. See PERFETTO_DEFINE_CATEGORIES. 103 #define PERFETTO_GET_CATEGORY_INDEX(category) \ 104 PERFETTO_TRACK_EVENT_NAMESPACE::internal::kConstExprCategoryRegistry.Find( \ 105 category, \ 106 ::PERFETTO_TRACK_EVENT_NAMESPACE::internal::IsDynamicCategory(category)) 107 108 // Generate a unique variable name with a given prefix. 109 #define PERFETTO_INTERNAL_CONCAT2(a, b) a##b 110 #define PERFETTO_INTERNAL_CONCAT(a, b) PERFETTO_INTERNAL_CONCAT2(a, b) 111 #define PERFETTO_UID(prefix) PERFETTO_INTERNAL_CONCAT(prefix, __LINE__) 112 113 // Efficiently determines whether tracing is enabled for the given category, and 114 // if so, emits one trace event with the given arguments. 115 #define PERFETTO_INTERNAL_TRACK_EVENT_WITH_METHOD(method, category, name, ...) \ 116 do { \ 117 ::perfetto::internal::ValidateEventNameType<decltype(name)>(); \ 118 namespace tns = PERFETTO_TRACK_EVENT_NAMESPACE; \ 119 /* Compute the category index outside the lambda to work around a */ \ 120 /* GCC 7 bug */ \ 121 constexpr auto PERFETTO_UID( \ 122 kCatIndex_ADD_TO_PERFETTO_DEFINE_CATEGORIES_IF_FAILS_) = \ 123 PERFETTO_GET_CATEGORY_INDEX(category); \ 124 if (::PERFETTO_TRACK_EVENT_NAMESPACE::internal::IsDynamicCategory( \ 125 category)) { \ 126 tns::TrackEvent::CallIfEnabled( \ 127 [&](uint32_t instances) PERFETTO_NO_THREAD_SAFETY_ANALYSIS { \ 128 tns::TrackEvent::method( \ 129 instances, category, \ 130 ::perfetto::internal::DecayEventNameType(name), \ 131 ##__VA_ARGS__); \ 132 }); \ 133 } else { \ 134 tns::TrackEvent::CallIfCategoryEnabled( \ 135 PERFETTO_UID(kCatIndex_ADD_TO_PERFETTO_DEFINE_CATEGORIES_IF_FAILS_), \ 136 [&](uint32_t instances) PERFETTO_NO_THREAD_SAFETY_ANALYSIS { \ 137 tns::TrackEvent::method( \ 138 instances, \ 139 PERFETTO_UID( \ 140 kCatIndex_ADD_TO_PERFETTO_DEFINE_CATEGORIES_IF_FAILS_), \ 141 ::perfetto::internal::DecayEventNameType(name), \ 142 ##__VA_ARGS__); \ 143 }); \ 144 } \ 145 } while (false) 146 147 // This internal macro is unused from the repo now, but some improper usage 148 // remain outside of the repo. 149 // TODO(b/294800182): Remove this. 150 #define PERFETTO_INTERNAL_TRACK_EVENT(...) \ 151 PERFETTO_INTERNAL_TRACK_EVENT_WITH_METHOD(TraceForCategory, ##__VA_ARGS__) 152 153 // C++17 doesn't like a move constructor being defined for the EventFinalizer 154 // class but C++11 and MSVC doesn't compile without it being defined so support 155 // both. 156 #if !PERFETTO_BUILDFLAG(PERFETTO_COMPILER_MSVC) 157 #define PERFETTO_INTERNAL_EVENT_FINALIZER_KEYWORD delete 158 #else 159 #define PERFETTO_INTERNAL_EVENT_FINALIZER_KEYWORD default 160 #endif 161 162 #define PERFETTO_INTERNAL_SCOPED_EVENT_FINALIZER(category) \ 163 struct PERFETTO_UID(ScopedEvent) { \ 164 struct EventFinalizer { \ 165 /* The parameter is an implementation detail. It allows the */ \ 166 /* anonymous struct to use aggregate initialization to invoke the */ \ 167 /* lambda (which emits the BEGIN event and returns an integer) */ \ 168 /* with the proper reference capture for any */ \ 169 /* TrackEventArgumentFunction in |__VA_ARGS__|. This is required so */ \ 170 /* that the scoped event is exactly ONE line and can't escape the */ \ 171 /* scope if used in a single line if statement. */ \ 172 EventFinalizer(...) {} \ 173 ~EventFinalizer() { \ 174 TRACE_EVENT_END(category); \ 175 } \ 176 \ 177 EventFinalizer(const EventFinalizer&) = delete; \ 178 inline EventFinalizer& operator=(const EventFinalizer&) = delete; \ 179 \ 180 EventFinalizer(EventFinalizer&&) = \ 181 PERFETTO_INTERNAL_EVENT_FINALIZER_KEYWORD; \ 182 EventFinalizer& operator=(EventFinalizer&&) = delete; \ 183 } finalizer; \ 184 } 185 186 #define PERFETTO_INTERNAL_SCOPED_TRACK_EVENT(category, name, ...) \ 187 PERFETTO_INTERNAL_SCOPED_EVENT_FINALIZER(category) \ 188 PERFETTO_UID(scoped_event) { \ 189 [&]() { \ 190 TRACE_EVENT_BEGIN(category, name, ##__VA_ARGS__); \ 191 return 0; \ 192 }() \ 193 } 194 195 #if PERFETTO_ENABLE_LEGACY_TRACE_EVENTS 196 // Required for TRACE_EVENT_WITH_FLOW legacy macros, which pass the bind_id as 197 // id. 198 #define PERFETTO_INTERNAL_SCOPED_LEGACY_TRACK_EVENT_WITH_ID( \ 199 category, name, track, flags, thread_id, id, ...) \ 200 PERFETTO_INTERNAL_SCOPED_EVENT_FINALIZER(category) \ 201 PERFETTO_UID(scoped_event) { \ 202 [&]() { \ 203 PERFETTO_INTERNAL_TRACK_EVENT_WITH_METHOD( \ 204 TraceForCategoryLegacyWithId, category, name, \ 205 ::perfetto::protos::pbzero::TrackEvent::TYPE_SLICE_BEGIN, track, \ 206 'B', flags, thread_id, id, ##__VA_ARGS__); \ 207 return 0; \ 208 }() \ 209 } 210 #endif // PERFETTO_ENABLE_LEGACY_TRACE_EVENTS 211 212 #if PERFETTO_BUILDFLAG(PERFETTO_COMPILER_GCC) || \ 213 PERFETTO_BUILDFLAG(PERFETTO_COMPILER_MSVC) 214 // On GCC versions <9 there's a bug that prevents using captured constant 215 // variables in constexpr evaluation inside a lambda: 216 // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82643 217 // TODO(khokhlov): Remove this fallback after Perfetto moves to a more recent 218 // GCC version. 219 #define PERFETTO_INTERNAL_CATEGORY_ENABLED(category) \ 220 (::PERFETTO_TRACK_EVENT_NAMESPACE::internal::IsDynamicCategory(category) \ 221 ? PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::IsDynamicCategoryEnabled( \ 222 ::perfetto::DynamicCategory(category)) \ 223 : PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::IsCategoryEnabled( \ 224 PERFETTO_GET_CATEGORY_INDEX(category))) 225 #else // !PERFETTO_BUILDFLAG(PERFETTO_COMPILER_GCC) 226 #define PERFETTO_INTERNAL_CATEGORY_ENABLED(category) \ 227 [&]() -> bool { \ 228 using PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent; \ 229 using ::PERFETTO_TRACK_EVENT_NAMESPACE::internal::IsDynamicCategory; \ 230 constexpr auto PERFETTO_UID(index) = \ 231 PERFETTO_GET_CATEGORY_INDEX(category); \ 232 constexpr auto PERFETTO_UID(dynamic) = IsDynamicCategory(category); \ 233 return PERFETTO_UID(dynamic) \ 234 ? TrackEvent::IsDynamicCategoryEnabled( \ 235 ::perfetto::DynamicCategory(category)) \ 236 : TrackEvent::IsCategoryEnabled(PERFETTO_UID(index)); \ 237 }() 238 #endif // !PERFETTO_BUILDFLAG(PERFETTO_COMPILER_GCC) 239 240 // Emits an empty trace packet into the trace to ensure that the service can 241 // safely read the last event from the trace buffer. This can be used to 242 // periodically "flush" the last event on threads that don't support explicit 243 // flushing of the shared memory buffer chunk when the tracing session stops 244 // (e.g. thread pool workers in Chromium). 245 // 246 // This workaround is only required because the tracing service cannot safely 247 // read the last trace packet from an incomplete SMB chunk (crbug.com/1021571 248 // and b/162206162) when scraping the SMB. Adding an empty trace packet ensures 249 // that all prior events can be scraped by the service. 250 #define PERFETTO_INTERNAL_ADD_EMPTY_EVENT() \ 251 do { \ 252 PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::Trace( \ 253 [](PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::TraceContext ctx) { \ 254 ctx.AddEmptyTracePacket(); \ 255 }); \ 256 } while (false) 257 258 #endif // INCLUDE_PERFETTO_TRACING_INTERNAL_TRACK_EVENT_MACROS_H_ 259