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 #include "perfetto/tracing/internal/tracing_tls.h"
18 #include "perfetto/tracing/tracing.h"
19 #include "perfetto/tracing/tracing_backend.h"
20
21 // This translation unit contains the definitions for the destructor of pure
22 // virtual interfaces for the src/public:public target. The alternative would be
23 // introducing a one-liner .cc file for each pure virtual interface, which is
24 // overkill. This is for compliance with -Wweak-vtables.
25
26 namespace perfetto {
27 namespace internal {
28
~TracingTLS()29 TracingTLS::~TracingTLS() {
30 // Avoid entering trace points while the thread is being torn down.
31 // This is the problem: when a thread exits, the at-thread-exit destroys the
32 // TracingTLS. As part of that the various TraceWriter for the active data
33 // sources are destroyd. A TraceWriter dtor will issue a PostTask on the IPC
34 // thread to issue a final flush and unregister its ID with the service.
35 // The PostTask, in chromium, might have a trace event that will try to
36 // re-enter the tracing system.
37 // We fix this by resetting the TLS key to the TracingTLS object that is
38 // being destroyed in the platform impl (platform_posix.cc,
39 // platform_windows.cc, chromium's platform.cc). We carefully rely on the fact
40 // that all the tracing path that will be invoked during thread exit will
41 // early out if |is_in_trace_point| == true and will not depend on the other
42 // TLS state that has been destroyed.
43 is_in_trace_point = true;
44 }
45
46 } // namespace internal
47
48 TracingProducerBackend::~TracingProducerBackend() = default;
49 TracingConsumerBackend::~TracingConsumerBackend() = default;
50 TracingBackend::~TracingBackend() = default;
51
52 } // namespace perfetto
53