1 files changed, 175 insertions, 0 deletions
diff --git a/src/tracing/platform_windows.cc b/src/tracing/platform_windows.cc
new file mode 100644
index 000000000..0f1664c76
--- /dev/null
+++ b/src/tracing/platform_windows.cc
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+#include "perfetto/base/build_config.h"
+
+#if PERFETTO_BUILDFLAG(PERFETTO_OS_WIN)
+
+#include <Windows.h>
+
+#include "perfetto/ext/base/thread_task_runner.h"
+#include "perfetto/tracing/internal/tracing_tls.h"
+#include "perfetto/tracing/platform.h"
+
+// Thread Termination Callbacks.
+// Windows doesn't support a per-thread destructor with its
+// TLS primitives. So, we build it manually by inserting a
+// function to be called on each thread's exit.
+// This magic is from chromium's base/threading/thread_local_storage_win.cc
+// which in turn is from http://www.codeproject.com/threads/tls.asp.
+
+#ifdef _WIN64
+#pragma comment(linker, "/INCLUDE:_tls_used")
+#pragma comment(linker, "/INCLUDE:perfetto_thread_callback_base")
+#else
+#pragma comment(linker, "/INCLUDE:__tls_used")
+#pragma comment(linker, "/INCLUDE:_perfetto_thread_callback_base")
+#endif
+
+namespace perfetto {
+
+namespace {
+
+class PlatformWindows : public Platform {
+ public:
+  static PlatformWindows* instance;
+  PlatformWindows();
+  ~PlatformWindows() override;
+
+  ThreadLocalObject* GetOrCreateThreadLocalObject() override;
+  std::unique_ptr<base::TaskRunner> CreateTaskRunner(
+      const CreateTaskRunnerArgs&) override;
+  std::string GetCurrentProcessName() override;
+  void OnThreadExit();
+
+ private:
+  DWORD tls_key_{};
+};
+
+using ThreadLocalObject = Platform::ThreadLocalObject;
+
+// static
+PlatformWindows* PlatformWindows::instance = nullptr;
+
+PlatformWindows::PlatformWindows() {
+  instance = this;
+  tls_key_ = ::TlsAlloc();
+  PERFETTO_CHECK(tls_key_ != TLS_OUT_OF_INDEXES);
+}
+
+PlatformWindows::~PlatformWindows() {
+  ::TlsFree(tls_key_);
+  instance = nullptr;
+}
+
+void PlatformWindows::OnThreadExit() {
+  auto tls = static_cast<ThreadLocalObject*>(::TlsGetValue(tls_key_));
+  if (tls) {
+    // At this point we rely on the TLS object to be still set to the TracingTLS
+    // we are deleting. See comments in TracingTLS::~TracingTLS().
+    delete tls;
+  }
+}
+
+ThreadLocalObject* PlatformWindows::GetOrCreateThreadLocalObject() {
+  void* tls_ptr = ::TlsGetValue(tls_key_);
+
+  auto* tls = static_cast<ThreadLocalObject*>(tls_ptr);
+  if (!tls) {
+    tls = ThreadLocalObject::CreateInstance().release();
+    ::TlsSetValue(tls_key_, tls);
+  }
+  return tls;
+}
+
+std::unique_ptr<base::TaskRunner> PlatformWindows::CreateTaskRunner(
+    const CreateTaskRunnerArgs& args) {
+  return std::unique_ptr<base::TaskRunner>(new base::ThreadTaskRunner(
+      base::ThreadTaskRunner::CreateAndStart(args.name_for_debugging)));
+}
+
+std::string PlatformWindows::GetCurrentProcessName() {
+  char buf[MAX_PATH];
+  auto len = ::GetModuleFileNameA(nullptr /*current*/, buf, sizeof(buf));
+  std::string name(buf, static_cast<size_t>(len));
+  size_t sep = name.find_last_of('\\');
+  if (sep != std::string::npos)
+    name = name.substr(sep + 1);
+  return name;
+}
+
+}  // namespace
+
+// static
+Platform* Platform::GetDefaultPlatform() {
+  static PlatformWindows* thread_safe_init_instance = new PlatformWindows();
+  return thread_safe_init_instance;
+}
+
+}  // namespace perfetto
+
+// -----------------------
+// Thread-local destructor
+// -----------------------
+
+// .CRT$XLA to .CRT$XLZ is an array of PIMAGE_TLS_CALLBACK pointers that are
+// called automatically by the OS loader code (not the CRT) when the module is
+// loaded and on thread creation. They are NOT called if the module has been
+// loaded by a LoadLibrary() call. It must have implicitly been loaded at
+// process startup.
+// See VC\crt\src\tlssup.c for reference.
+
+// extern "C" suppresses C++ name mangling so we know the symbol name for the
+// linker /INCLUDE:symbol pragma above.
+extern "C" {
+// The linker must not discard perfetto_thread_callback_base. (We force a
+// reference to this variable with a linker /INCLUDE:symbol pragma to ensure
+// that.) If this variable is discarded, the OnThreadExit function will never be
+// called.
+
+void NTAPI PerfettoOnThreadExit(PVOID, DWORD, PVOID);
+void NTAPI PerfettoOnThreadExit(PVOID module, DWORD reason, PVOID reserved) {
+  if (reason == DLL_THREAD_DETACH || reason == DLL_PROCESS_DETACH) {
+    if (perfetto::PlatformWindows::instance)
+      perfetto::PlatformWindows::instance->OnThreadExit();
+  }
+}
+
+#ifdef _WIN64
+
+// .CRT section is merged with .rdata on x64 so it must be constant data.
+#pragma const_seg(".CRT$XLP")
+
+// When defining a const variable, it must have external linkage to be sure the
+// linker doesn't discard it.
+extern const PIMAGE_TLS_CALLBACK perfetto_thread_callback_base;
+const PIMAGE_TLS_CALLBACK perfetto_thread_callback_base = PerfettoOnThreadExit;
+
+// Reset the default section.
+#pragma const_seg()
+
+#else  // _WIN64
+
+#pragma data_seg(".CRT$XLP")
+PIMAGE_TLS_CALLBACK perfetto_thread_callback_base = PerfettoOnThreadExit;
+// Reset the default section.
+#pragma data_seg()
+
+#endif  // _WIN64
+
+}  // extern "C"
+
+#endif  // OS_WIN