| OLD | NEW |
| (Empty) |
| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "base/threading/thread_local_storage.h" | |
| 6 | |
| 7 #include <windows.h> | |
| 8 | |
| 9 #include "base/logging.h" | |
| 10 | |
| 11 namespace base { | |
| 12 | |
| 13 namespace internal { | |
| 14 | |
| 15 bool PlatformThreadLocalStorage::AllocTLS(TLSKey* key) { | |
| 16 TLSKey value = TlsAlloc(); | |
| 17 if (value != TLS_OUT_OF_INDEXES) { | |
| 18 *key = value; | |
| 19 return true; | |
| 20 } | |
| 21 return false; | |
| 22 } | |
| 23 | |
| 24 void PlatformThreadLocalStorage::FreeTLS(TLSKey key) { | |
| 25 BOOL ret = TlsFree(key); | |
| 26 DCHECK(ret); | |
| 27 } | |
| 28 | |
| 29 void* PlatformThreadLocalStorage::GetTLSValue(TLSKey key) { | |
| 30 return TlsGetValue(key); | |
| 31 } | |
| 32 | |
| 33 void PlatformThreadLocalStorage::SetTLSValue(TLSKey key, void* value) { | |
| 34 BOOL ret = TlsSetValue(key, value); | |
| 35 DCHECK(ret); | |
| 36 } | |
| 37 | |
| 38 } // namespace internal | |
| 39 | |
| 40 } // namespace base | |
| 41 | |
| 42 // Thread Termination Callbacks. | |
| 43 // Windows doesn't support a per-thread destructor with its | |
| 44 // TLS primitives. So, we build it manually by inserting a | |
| 45 // function to be called on each thread's exit. | |
| 46 // This magic is from http://www.codeproject.com/threads/tls.asp | |
| 47 // and it works for VC++ 7.0 and later. | |
| 48 | |
| 49 // Force a reference to _tls_used to make the linker create the TLS directory | |
| 50 // if it's not already there. (e.g. if __declspec(thread) is not used). | |
| 51 // Force a reference to p_thread_callback_base to prevent whole program | |
| 52 // optimization from discarding the variable. | |
| 53 #ifdef _WIN64 | |
| 54 | |
| 55 #pragma comment(linker, "/INCLUDE:_tls_used") | |
| 56 #pragma comment(linker, "/INCLUDE:p_thread_callback_base") | |
| 57 | |
| 58 #else // _WIN64 | |
| 59 | |
| 60 #pragma comment(linker, "/INCLUDE:__tls_used") | |
| 61 #pragma comment(linker, "/INCLUDE:_p_thread_callback_base") | |
| 62 | |
| 63 #endif // _WIN64 | |
| 64 | |
| 65 // Static callback function to call with each thread termination. | |
| 66 void NTAPI OnThreadExit(PVOID module, DWORD reason, PVOID reserved) { | |
| 67 // On XP SP0 & SP1, the DLL_PROCESS_ATTACH is never seen. It is sent on SP2+ | |
| 68 // and on W2K and W2K3. So don't assume it is sent. | |
| 69 if (DLL_THREAD_DETACH == reason || DLL_PROCESS_DETACH == reason) | |
| 70 base::internal::PlatformThreadLocalStorage::OnThreadExit(); | |
| 71 } | |
| 72 | |
| 73 // .CRT$XLA to .CRT$XLZ is an array of PIMAGE_TLS_CALLBACK pointers that are | |
| 74 // called automatically by the OS loader code (not the CRT) when the module is | |
| 75 // loaded and on thread creation. They are NOT called if the module has been | |
| 76 // loaded by a LoadLibrary() call. It must have implicitly been loaded at | |
| 77 // process startup. | |
| 78 // By implicitly loaded, I mean that it is directly referenced by the main EXE | |
| 79 // or by one of its dependent DLLs. Delay-loaded DLL doesn't count as being | |
| 80 // implicitly loaded. | |
| 81 // | |
| 82 // See VC\crt\src\tlssup.c for reference. | |
| 83 | |
| 84 // extern "C" suppresses C++ name mangling so we know the symbol name for the | |
| 85 // linker /INCLUDE:symbol pragma above. | |
| 86 extern "C" { | |
| 87 // The linker must not discard p_thread_callback_base. (We force a reference | |
| 88 // to this variable with a linker /INCLUDE:symbol pragma to ensure that.) If | |
| 89 // this variable is discarded, the OnThreadExit function will never be called. | |
| 90 #ifdef _WIN64 | |
| 91 | |
| 92 // .CRT section is merged with .rdata on x64 so it must be constant data. | |
| 93 #pragma const_seg(".CRT$XLB") | |
| 94 // When defining a const variable, it must have external linkage to be sure the | |
| 95 // linker doesn't discard it. | |
| 96 extern const PIMAGE_TLS_CALLBACK p_thread_callback_base; | |
| 97 const PIMAGE_TLS_CALLBACK p_thread_callback_base = OnThreadExit; | |
| 98 | |
| 99 // Reset the default section. | |
| 100 #pragma const_seg() | |
| 101 | |
| 102 #else // _WIN64 | |
| 103 | |
| 104 #pragma data_seg(".CRT$XLB") | |
| 105 PIMAGE_TLS_CALLBACK p_thread_callback_base = OnThreadExit; | |
| 106 | |
| 107 // Reset the default section. | |
| 108 #pragma data_seg() | |
| 109 | |
| 110 #endif // _WIN64 | |
| 111 } // extern "C" | |
| OLD | NEW |