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/track_event_category_registry.h" 27 28 // Ignore GCC warning about a missing argument for a variadic macro parameter. 29 #if defined(__GNUC__) || defined(__clang__) 30 #pragma GCC system_header 31 #endif 32 33 // Defines data structures for backing a category registry. 34 // 35 // Each category has one enabled/disabled bit per possible data source instance. 36 // The bits are packed, i.e., each byte holds the state for instances. To 37 // improve cache locality, the bits for each instance are stored separately from 38 // the names of the categories: 39 // 40 // byte 0 byte 1 41 // (inst0, inst1, ..., inst7), (inst0, inst1, ..., inst7) 42 // 43 #define PERFETTO_INTERNAL_DECLARE_CATEGORIES(...) \ 44 namespace internal { \ 45 constexpr ::perfetto::Category kCategories[] = {__VA_ARGS__}; \ 46 constexpr size_t kCategoryCount = \ 47 sizeof(kCategories) / sizeof(kCategories[0]); \ 48 /* The per-instance enable/disable state per category */ \ 49 PERFETTO_COMPONENT_EXPORT extern std::atomic<uint8_t> \ 50 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 PERFETTO_COMPONENT_EXPORT extern const ::perfetto::internal:: \ 72 TrackEventCategoryRegistry 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() \ 79 namespace internal { \ 80 PERFETTO_COMPONENT_EXPORT std::atomic<uint8_t> \ 81 g_category_state_storage[kCategoryCount]; \ 82 PERFETTO_COMPONENT_EXPORT const ::perfetto::internal:: \ 83 TrackEventCategoryRegistry kCategoryRegistry( \ 84 kCategoryCount, \ 85 &kCategories[0], \ 86 &g_category_state_storage[0]); \ 87 } // namespace internal 88 89 // Defines the TrackEvent data source for the current track event namespace. 90 // `virtual ~TrackEvent` is added to avoid `-Wweak-vtables` warning. 91 // Learn more : aosp/2019906 92 #define PERFETTO_INTERNAL_DECLARE_TRACK_EVENT_DATA_SOURCE() \ 93 struct PERFETTO_COMPONENT_EXPORT TrackEvent \ 94 : public ::perfetto::internal::TrackEventDataSource< \ 95 TrackEvent, &internal::kCategoryRegistry> { \ 96 virtual ~TrackEvent(); \ 97 } 98 99 #define PERFETTO_INTERNAL_DEFINE_TRACK_EVENT_DATA_SOURCE() \ 100 TrackEvent::~TrackEvent() = default; 101 102 // At compile time, turns a category name represented by a static string into an 103 // index into the current category registry. A build error will be generated if 104 // the category hasn't been registered or added to the list of allowed dynamic 105 // categories. See PERFETTO_DEFINE_CATEGORIES. 106 #define PERFETTO_GET_CATEGORY_INDEX(category) \ 107 ::PERFETTO_TRACK_EVENT_NAMESPACE::internal::kConstExprCategoryRegistry.Find( \ 108 category, \ 109 ::PERFETTO_TRACK_EVENT_NAMESPACE::internal::IsDynamicCategory(category)) 110 111 // Generate a unique variable name with a given prefix. 112 #define PERFETTO_INTERNAL_CONCAT2(a, b) a##b 113 #define PERFETTO_INTERNAL_CONCAT(a, b) PERFETTO_INTERNAL_CONCAT2(a, b) 114 #define PERFETTO_UID(prefix) PERFETTO_INTERNAL_CONCAT(prefix, __LINE__) 115 116 // Efficiently determines whether tracing is enabled for the given category, and 117 // if so, emits one trace event with the given arguments. 118 #define PERFETTO_INTERNAL_TRACK_EVENT(category, ...) \ 119 do { \ 120 namespace tns = ::PERFETTO_TRACK_EVENT_NAMESPACE; \ 121 /* Compute the category index outside the lambda to work around a */ \ 122 /* GCC 7 bug */ \ 123 static constexpr auto PERFETTO_UID( \ 124 kCatIndex_ADD_TO_PERFETTO_DEFINE_CATEGORIES_IF_FAILS_) = \ 125 PERFETTO_GET_CATEGORY_INDEX(category); \ 126 if (tns::internal::IsDynamicCategory(category)) { \ 127 tns::TrackEvent::CallIfEnabled( \ 128 [&](uint32_t instances) PERFETTO_NO_THREAD_SAFETY_ANALYSIS { \ 129 tns::TrackEvent::TraceForCategory(instances, category, \ 130 ##__VA_ARGS__); \ 131 }); \ 132 } else { \ 133 tns::TrackEvent::CallIfCategoryEnabled( \ 134 PERFETTO_UID(kCatIndex_ADD_TO_PERFETTO_DEFINE_CATEGORIES_IF_FAILS_), \ 135 [&](uint32_t instances) PERFETTO_NO_THREAD_SAFETY_ANALYSIS { \ 136 tns::TrackEvent::TraceForCategory( \ 137 instances, \ 138 PERFETTO_UID( \ 139 kCatIndex_ADD_TO_PERFETTO_DEFINE_CATEGORIES_IF_FAILS_), \ 140 ##__VA_ARGS__); \ 141 }); \ 142 } \ 143 } while (false) 144 145 #define PERFETTO_INTERNAL_SCOPED_TRACK_EVENT(category, name, ...) \ 146 struct PERFETTO_UID(ScopedEvent) { \ 147 struct EventFinalizer { \ 148 /* The parameter is an implementation detail. It allows the */ \ 149 /* anonymous struct to use aggregate initialization to invoke the */ \ 150 /* lambda (which emits the BEGIN event and returns an integer) */ \ 151 /* with the proper reference capture for any */ \ 152 /* TrackEventArgumentFunction in |__VA_ARGS__|. This is required so */ \ 153 /* that the scoped event is exactly ONE line and can't escape the */ \ 154 /* scope if used in a single line if statement. */ \ 155 EventFinalizer(...) {} \ 156 ~EventFinalizer() { TRACE_EVENT_END(category); } \ 157 } finalizer; \ 158 } PERFETTO_UID(scoped_event) { \ 159 [&]() { \ 160 TRACE_EVENT_BEGIN(category, name, ##__VA_ARGS__); \ 161 return 0; \ 162 }() \ 163 } 164 165 #define PERFETTO_INTERNAL_CATEGORY_ENABLED(category) \ 166 (::PERFETTO_TRACK_EVENT_NAMESPACE::internal::IsDynamicCategory(category) \ 167 ? ::PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent:: \ 168 IsDynamicCategoryEnabled(::perfetto::DynamicCategory(category)) \ 169 : ::PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::IsCategoryEnabled( \ 170 PERFETTO_GET_CATEGORY_INDEX(category))) 171 172 // Emits an empty trace packet into the trace to ensure that the service can 173 // safely read the last event from the trace buffer. This can be used to 174 // periodically "flush" the last event on threads that don't support explicit 175 // flushing of the shared memory buffer chunk when the tracing session stops 176 // (e.g. thread pool workers in Chromium). 177 // 178 // This workaround is only required because the tracing service cannot safely 179 // read the last trace packet from an incomplete SMB chunk (crbug.com/1021571 180 // and b/162206162) when scraping the SMB. Adding an empty trace packet ensures 181 // that all prior events can be scraped by the service. 182 #define PERFETTO_INTERNAL_ADD_EMPTY_EVENT() \ 183 do { \ 184 ::PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::Trace( \ 185 [](::PERFETTO_TRACK_EVENT_NAMESPACE::TrackEvent::TraceContext ctx) { \ 186 ctx.NewTracePacket(); \ 187 }); \ 188 } while (false) 189 190 #endif // INCLUDE_PERFETTO_TRACING_INTERNAL_TRACK_EVENT_MACROS_H_ 191