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| 1 //===- subzero/src/IceTLS.h - thread_local workaround -----------*- C++ -*-===// |
| 2 // |
| 3 // The Subzero Code Generator |
| 4 // |
| 5 // This file is distributed under the University of Illinois Open Source |
| 6 // License. See LICENSE.TXT for details. |
| 7 // |
| 8 //===----------------------------------------------------------------------===// |
| 9 // |
| 10 // This file defines macros for working around the lack of support for |
| 11 // thread_local in MacOS 10.6. It assumes std::thread is written in |
| 12 // terms of pthread. Define ICE_THREAD_LOCAL_HACK to enable the |
| 13 // pthread workarounds. |
| 14 // |
| 15 //===----------------------------------------------------------------------===// |
| 16 |
| 17 #ifndef SUBZERO_SRC_ICETLS_H |
| 18 #define SUBZERO_SRC_ICETLS_H |
| 19 |
| 20 #if defined(_MSC_VER) |
| 21 #define ICE_ATTRIBUTE_TLS __declspec(thread) |
| 22 #else // !_MSC_VER |
| 23 #define ICE_ATTRIBUTE_TLS thread_local |
| 24 #endif // !_MSC_VER |
| 25 |
| 26 // Defines 4 macros for unifying thread_local and pthread: |
| 27 // |
| 28 // ICE_TLS_DECLARE_FIELD(Type, FieldName): Declare a static |
| 29 // thread_local field inside the current class definition. "Type" |
| 30 // needs to be a pointer type, such as int* or class Foo*. |
| 31 // |
| 32 // ICE_TLS_DEFINE_FIELD(Type, ClassName, FieldName): Define a static |
| 33 // thread_local field outside of its class definition. The field will |
| 34 // ultimately be initialized to nullptr. |
| 35 // |
| 36 // ICE_TLS_INIT_FIELD(FieldName): Ensure the thread_local field is |
| 37 // properly initialized. This is intended to be called from within a |
| 38 // static method of the field's class after main() starts (to ensure |
| 39 // that the pthread library is fully initialized) but before any uses |
| 40 // of ICE_TLS_GET_FIELD or ICE_TLS_SET_FIELD. |
| 41 // |
| 42 // ICE_TLS_GET_FIELD(Type, FieldName): Read the value of the static |
| 43 // thread_local field. Must be done within the context of its class. |
| 44 // |
| 45 // ICE_TLS_SET_FIELD(FieldName, Value): Write a value into the static |
| 46 // thread_local field. Must be done within the context of its class. |
| 47 |
| 48 // TODO(stichnot): Limit this define to only the platforms that |
| 49 // absolutely require it. And ideally, eventually remove this hack |
| 50 // altogether. |
| 51 #define ICE_THREAD_LOCAL_HACK |
| 52 #ifdef ICE_THREAD_LOCAL_HACK |
| 53 |
| 54 // For a static thread_local field F of a class C, instead of |
| 55 // declaring and defining C::F, we create two static fields: |
| 56 // static pthread_key_t F__key; |
| 57 // static int F__initStatus; |
| 58 // |
| 59 // The F__initStatus field is used to hold the result of the |
| 60 // pthread_key_create() call, where a zero value indicates success, |
| 61 // and a nonzero value indicates failure or that ICE_TLS_INIT_FIELD() |
| 62 // was never called. |
| 63 // The F__key field is used as the argument to |
| 64 // pthread_getspecific() and pthread_setspecific(). |
| 65 |
| 66 #include <pthread.h> |
| 67 |
| 68 #define ICE_TLS_DECLARE_FIELD(Type, FieldName) \ |
| 69 typedef Type FieldName##__type; \ |
| 70 static pthread_key_t FieldName##__key; \ |
| 71 static int FieldName##__initStatus |
| 72 #define ICE_TLS_DEFINE_FIELD(Type, ClassName, FieldName) \ |
| 73 pthread_key_t ClassName::FieldName##__key; \ |
| 74 int ClassName::FieldName##__initStatus = 1; |
| 75 #define ICE_TLS_INIT_FIELD(FieldName) \ |
| 76 if (FieldName##__initStatus) { \ |
| 77 FieldName##__initStatus = pthread_key_create(&FieldName##__key, nullptr); \ |
| 78 if (FieldName##__initStatus) \ |
| 79 llvm::report_fatal_error("Failed to create pthread key"); \ |
| 80 } |
| 81 #define ICE_TLS_GET_FIELD(FieldName) \ |
| 82 (assert(FieldName##__initStatus == 0), \ |
| 83 static_cast<FieldName##__type>(pthread_getspecific(FieldName##__key))) |
| 84 #define ICE_TLS_SET_FIELD(FieldName, Value) \ |
| 85 (assert(FieldName##__initStatus == 0), \ |
| 86 pthread_setspecific(FieldName##__key, (Value))) |
| 87 |
| 88 #else // !ICE_THREAD_LOCAL_HACK |
| 89 |
| 90 #define ICE_TLS_DECLARE_FIELD(Type, FieldName) \ |
| 91 static ICE_ATTRIBUTE_TLS Type FieldName |
| 92 #define ICE_TLS_DEFINE_FIELD(Type, ClassName, FieldName) \ |
| 93 ICE_ATTRIBUTE_TLS Type ClassName::FieldName = nullptr |
| 94 #define ICE_TLS_INIT_FIELD(FieldName) |
| 95 #define ICE_TLS_GET_FIELD(FieldName) (FieldName) |
| 96 #define ICE_TLS_SET_FIELD(FieldName, Value) (FieldName = (Value)) |
| 97 |
| 98 #endif // !ICE_THREAD_LOCAL_HACK |
| 99 |
| 100 #endif // SUBZERO_SRC_ICETLS_H |
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