1 //===- llvm/Support/ThreadLocal.h - Thread Local Data ------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file declares the llvm::sys::ThreadLocal class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_SUPPORT_THREADLOCAL_H 14 #define LLVM_SUPPORT_THREADLOCAL_H 15 16 #include "llvm/Support/DataTypes.h" 17 #include "llvm/Support/Threading.h" 18 #include <cassert> 19 20 namespace llvm { 21 namespace sys { 22 // ThreadLocalImpl - Common base class of all ThreadLocal instantiations. 23 // YOU SHOULD NEVER USE THIS DIRECTLY. 24 class ThreadLocalImpl { 25 typedef uint64_t ThreadLocalDataTy; 26 /// Platform-specific thread local data. 27 /// 28 /// This is embedded in the class and we avoid malloc'ing/free'ing it, 29 /// to make this class more safe for use along with CrashRecoveryContext. 30 union { 31 char data[sizeof(ThreadLocalDataTy)]; 32 ThreadLocalDataTy align_data; 33 }; 34 public: 35 ThreadLocalImpl(); 36 virtual ~ThreadLocalImpl(); 37 void setInstance(const void* d); 38 void *getInstance(); 39 void removeInstance(); 40 }; 41 42 /// ThreadLocal - A class used to abstract thread-local storage. It holds, 43 /// for each thread, a pointer a single object of type T. 44 template<class T> 45 class ThreadLocal : public ThreadLocalImpl { 46 public: ThreadLocal()47 ThreadLocal() : ThreadLocalImpl() { } 48 49 /// get - Fetches a pointer to the object associated with the current 50 /// thread. If no object has yet been associated, it returns NULL; get()51 T* get() { return static_cast<T*>(getInstance()); } 52 53 // set - Associates a pointer to an object with the current thread. set(T * d)54 void set(T* d) { setInstance(d); } 55 56 // erase - Removes the pointer associated with the current thread. erase()57 void erase() { removeInstance(); } 58 }; 59 } 60 } 61 62 #endif 63