text: //===- ThreadLocal.cpp - Thread Local Data ----------------------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file implements the llvm::sys::ThreadLocal class.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/Config/config.h"
  #include "llvm/Support/Compiler.h"
  #include "llvm/Support/ThreadLocal.h"
  
  //===----------------------------------------------------------------------===//
  //=== WARNING: Implementation here must contain only TRULY operating system
  //===          independent code.
  //===----------------------------------------------------------------------===//
  
  #if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0
  // Define all methods as no-ops if threading is explicitly disabled
  namespace llvm {
  using namespace sys;
  ThreadLocalImpl::ThreadLocalImpl() : data() { }
  ThreadLocalImpl::~ThreadLocalImpl() { }
  void ThreadLocalImpl::setInstance(const void* d) {
    static_assert(sizeof(d) <= sizeof(data), "size too big");
    void **pd = reinterpret_cast<void**>(&data);
    *pd = const_cast<void*>(d);
  }
  const void* ThreadLocalImpl::getInstance() {
    void **pd = reinterpret_cast<void**>(&data);
    return *pd;
  }
  void ThreadLocalImpl::removeInstance() {
    setInstance(0);
  }
  }
  #else
  
  #if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_GETSPECIFIC)
  
  #include <cassert>
  #include <pthread.h>
  #include <stdlib.h>
  
  namespace llvm {
  using namespace sys;
  
  ThreadLocalImpl::ThreadLocalImpl() : data() {
    static_assert(sizeof(pthread_key_t) <= sizeof(data), "size too big");
    pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
    int errorcode = pthread_key_create(key, nullptr);
    assert(errorcode == 0);
    (void) errorcode;
  }
  
  ThreadLocalImpl::~ThreadLocalImpl() {
    pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
    int errorcode = pthread_key_delete(*key);
    assert(errorcode == 0);
    (void) errorcode;
  }
  
  void ThreadLocalImpl::setInstance(const void* d) {
    pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
    int errorcode = pthread_setspecific(*key, d);
    assert(errorcode == 0);
    (void) errorcode;
  }
  
  const void* ThreadLocalImpl::getInstance() {
    pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
    return pthread_getspecific(*key);
  }
  
  void ThreadLocalImpl::removeInstance() {
    setInstance(nullptr);
  }
  
  }
  
  #elif defined(LLVM_ON_UNIX)
  #include "Unix/ThreadLocal.inc"
  #elif defined( LLVM_ON_WIN32)
  #include "Windows/ThreadLocal.inc"
  #else
  #warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 set in Support/ThreadLocal.cpp
  #endif
  #endif
  