Move thread local stuff from base to base/threading and consistently use the...

base/thread_local_storage_win.cc

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/thread_local_storage.h"
-
-#include <windows.h>
-
-#include "base/logging.h"
-
-// In order to make TLS destructors work, we need to keep function
-// pointers to the destructor for each TLS that we allocate.
-// We make this work by allocating a single OS-level TLS, which
-// contains an array of slots for the application to use.  In
-// parallel, we also allocate an array of destructors, which we
-// keep track of and call when threads terminate.
-
-// tls_key_ is the one native TLS that we use.  It stores our
-// table.
-long ThreadLocalStorage::tls_key_ = TLS_OUT_OF_INDEXES;
-
-// tls_max_ is the high-water-mark of allocated thread local storage.
-// We intentionally skip 0 so that it is not confused with an
-// unallocated TLS slot.
-long ThreadLocalStorage::tls_max_ = 1;
-
-// An array of destructor function pointers for the slots.  If
-// a slot has a destructor, it will be stored in its corresponding
-// entry in this array.
-ThreadLocalStorage::TLSDestructorFunc
-  ThreadLocalStorage::tls_destructors_[kThreadLocalStorageSize];
-
-void** ThreadLocalStorage::Initialize() {
-  if (tls_key_ == TLS_OUT_OF_INDEXES) {
-    long value = TlsAlloc();
-    DCHECK(value != TLS_OUT_OF_INDEXES);
-
-    // Atomically test-and-set the tls_key.  If the key is TLS_OUT_OF_INDEXES,
-    // go ahead and set it.  Otherwise, do nothing, as another
-    // thread already did our dirty work.
-    if (InterlockedCompareExchange(&tls_key_, value, TLS_OUT_OF_INDEXES) !=
-            TLS_OUT_OF_INDEXES) {
-      // We've been shortcut. Another thread replaced tls_key_ first so we need
-      // to destroy our index and use the one the other thread got first.
-      TlsFree(value);
-    }
-  }
-  DCHECK(TlsGetValue(tls_key_) == NULL);
-
-  // Create an array to store our data.
-  void** tls_data = new void*[kThreadLocalStorageSize];
-  memset(tls_data, 0, sizeof(void*[kThreadLocalStorageSize]));
-  TlsSetValue(tls_key_, tls_data);
-  return tls_data;
-}
-
-ThreadLocalStorage::Slot::Slot(TLSDestructorFunc destructor)
-    : initialized_(false) {
-  Initialize(destructor);
-}
-
-bool ThreadLocalStorage::Slot::Initialize(TLSDestructorFunc destructor) {
-  if (tls_key_ == TLS_OUT_OF_INDEXES || !TlsGetValue(tls_key_))
-    ThreadLocalStorage::Initialize();
-
-  // Grab a new slot.
-  slot_ = InterlockedIncrement(&tls_max_) - 1;
-  if (slot_ >= kThreadLocalStorageSize) {
-    NOTREACHED();
-    return false;
-  }
-
-  // Setup our destructor.
-  tls_destructors_[slot_] = destructor;
-  initialized_ = true;
-  return true;
-}
-
-void ThreadLocalStorage::Slot::Free() {
-  // At this time, we don't reclaim old indices for TLS slots.
-  // So all we need to do is wipe the destructor.
-  tls_destructors_[slot_] = NULL;
-  initialized_ = false;
-}
-
-void* ThreadLocalStorage::Slot::Get() const {
-  void** tls_data = static_cast<void**>(TlsGetValue(tls_key_));
-  if (!tls_data)
-    tls_data = ThreadLocalStorage::Initialize();
-  DCHECK(slot_ >= 0 && slot_ < kThreadLocalStorageSize);
-  return tls_data[slot_];
-}
-
-void ThreadLocalStorage::Slot::Set(void* value) {
-  void** tls_data = static_cast<void**>(TlsGetValue(tls_key_));
-  if (!tls_data)
-    tls_data = ThreadLocalStorage::Initialize();
-  DCHECK(slot_ >= 0 && slot_ < kThreadLocalStorageSize);
-  tls_data[slot_] = value;
-}
-
-void ThreadLocalStorage::ThreadExit() {
-  if (tls_key_ == TLS_OUT_OF_INDEXES)
-    return;
-
-  void** tls_data = static_cast<void**>(TlsGetValue(tls_key_));
-
-  // Maybe we have never initialized TLS for this thread.
-  if (!tls_data)
-    return;
-
-  for (int slot = 0; slot < tls_max_; slot++) {
-    if (tls_destructors_[slot] != NULL) {
-      void* value = tls_data[slot];
-      tls_destructors_[slot](value);
-    }
-  }
-
-  delete[] tls_data;
-
-  // In case there are other "onexit" handlers...
-  TlsSetValue(tls_key_, NULL);
-}
-
-// 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 http://www.codeproject.com/threads/tls.asp
-// and it works for VC++ 7.0 and later.
-
-// Force a reference to _tls_used to make the linker create the TLS directory
-// if it's not already there.  (e.g. if __declspec(thread) is not used).
-// Force a reference to p_thread_callback_base to prevent whole program
-// optimization from discarding the variable.
-#ifdef _WIN64
-
-#pragma comment(linker, "/INCLUDE:_tls_used")
-#pragma comment(linker, "/INCLUDE:p_thread_callback_base")
-
-#else  // _WIN64
-
-#pragma comment(linker, "/INCLUDE:__tls_used")
-#pragma comment(linker, "/INCLUDE:_p_thread_callback_base")
-
-#endif  // _WIN64
-
-// Static callback function to call with each thread termination.
-void NTAPI OnThreadExit(PVOID module, DWORD reason, PVOID reserved) {
-  // On XP SP0 & SP1, the DLL_PROCESS_ATTACH is never seen. It is sent on SP2+
-  // and on W2K and W2K3. So don't assume it is sent.
-  if (DLL_THREAD_DETACH == reason || DLL_PROCESS_DETACH == reason)
-    ThreadLocalStorage::ThreadExit();
-}
-
-// .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.
-// By implicitly loaded, I mean that it is directly referenced by the main EXE
-// or by one of its dependent DLLs. Delay-loaded DLL doesn't count as being
-// implicitly loaded.
-//
-// 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 p_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.
-#ifdef _WIN64
-
-// .CRT section is merged with .rdata on x64 so it must be constant data.
-#pragma const_seg(".CRT$XLB")
-// When defining a const variable, it must have external linkage to be sure the
-// linker doesn't discard it.
-extern const PIMAGE_TLS_CALLBACK p_thread_callback_base;
-const PIMAGE_TLS_CALLBACK p_thread_callback_base = OnThreadExit;
-
-// Reset the default section.
-#pragma const_seg()
-
-#else  // _WIN64
-
-#pragma data_seg(".CRT$XLB")
-PIMAGE_TLS_CALLBACK p_thread_callback_base = OnThreadExit;
-
-// Reset the default section.
-#pragma data_seg()
-
-#endif  // _WIN64
-}  // extern "C"