LLVM  10.0.0svn
ThreadLocal.h
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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.
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:
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:
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;
51  T* get() { return static_cast<T*>(getInstance()); }
52 
53  // set - Associates a pointer to an object with the current thread.
54  void set(T* d) { setInstance(d); }
55 
56  // erase - Removes the pointer associated with the current thread.
57  void erase() { removeInstance(); }
58  };
59  }
60 }
61 
62 #endif
This class represents lattice values for constants.
Definition: AllocatorList.h:23
char data[sizeof(ThreadLocalDataTy)]
Definition: ThreadLocal.h:31
ThreadLocal - A class used to abstract thread-local storage.
Definition: ThreadLocal.h:45
void setInstance(const void *d)
ThreadLocalDataTy align_data
Definition: ThreadLocal.h:32