// Copyright 2024 The Abseil Authors // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // https://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. #ifndef ABSL_BASE_INTERNAL_TRACING_H_ #define ABSL_BASE_INTERNAL_TRACING_H_ #include "absl/base/config.h" namespace absl { ABSL_NAMESPACE_BEGIN namespace base_internal { // Well known Abseil object types that have causality. enum class ObjectKind { … }; // `TraceWait` and `TraceContinue` record the start and end of a potentially // blocking wait operation on `object`. `object` typically represents a higher // level synchronization object such as `absl::Notification`. void TraceWait(const void* object, ObjectKind kind); void TraceContinue(const void* object, ObjectKind kind); // `TraceSignal` records a signal on `object`. void TraceSignal(const void* object, ObjectKind kind); // `TraceObserved` records the non-blocking observation of a signaled object. void TraceObserved(const void* object, ObjectKind kind); // --------------------------------------------------------------------------- // Weak implementation detail: // // We define the weak API as extern "C": in some build configurations we pass // `--detect-odr-violations` to the gold linker. This causes it to flag weak // symbol overrides as ODR violations. Because ODR only applies to C++ and not // C, `--detect-odr-violations` ignores symbols not mangled with C++ names. // By changing our extension points to be extern "C", we dodge this check. // --------------------------------------------------------------------------- extern "C" { void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceWait)(const void* object, ObjectKind kind); void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceContinue)(const void* object, ObjectKind kind); void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceSignal)(const void* object, ObjectKind kind); void ABSL_INTERNAL_C_SYMBOL(AbslInternalTraceObserved)(const void* object, ObjectKind kind); } // extern "C" inline void TraceWait(const void* object, ObjectKind kind) { … } inline void TraceContinue(const void* object, ObjectKind kind) { … } inline void TraceSignal(const void* object, ObjectKind kind) { … } inline void TraceObserved(const void* object, ObjectKind kind) { … } } // namespace base_internal ABSL_NAMESPACE_END } // namespace absl #endif // ABSL_BASE_INTERNAL_TRACING_H_