lib/Support/ManagedStatic.cpp

   1 //===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   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 implements the ManagedStatic class and llvm_shutdown().
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Support/ManagedStatic.h"
  15 #include "llvm/Config/config.h"
  16 #include "llvm/System/Atomic.h"
  17 #include <cassert>
  18 using namespace llvm;
  19
  20 static const ManagedStaticBase *StaticList = 0;
  21
  22 void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
  23                                               void (*Deleter)(void*)) const {
  24   if (llvm_is_multithreaded()) {
  25     llvm_acquire_global_lock();
  26
  27     if (Ptr == 0) {
  28       void* tmp = Creator ? Creator() : 0;
  29
  30       sys::MemoryFence();
  31       Ptr = tmp;
  32       DeleterFn = Deleter;
  33
  34       // Add to list of managed statics.
  35       Next = StaticList;
  36       StaticList = this;
  37     }
  38
  39     llvm_release_global_lock();
  40   } else {
  41     assert(Ptr == 0 && DeleterFn == 0 && Next == 0 &&
  42            "Partially initialized ManagedStatic!?");
  43     Ptr = Creator ? Creator() : 0;
  44     DeleterFn = Deleter;
  45
  46     // Add to list of managed statics.
  47     Next = StaticList;
  48     StaticList = this;
  49   }
  50 }
  51
  52 void ManagedStaticBase::destroy() const {
  53   assert(DeleterFn && "ManagedStatic not initialized correctly!");
  54   assert(StaticList == this &&
  55          "Not destroyed in reverse order of construction?");
  56   // Unlink from list.
  57   StaticList = Next;
  58   Next = 0;
  59
  60   // Destroy memory.
  61   DeleterFn(Ptr);
  62
  63   // Cleanup.
  64   Ptr = 0;
  65   DeleterFn = 0;
  66 }
  67
  68 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
  69 void llvm::llvm_shutdown() {
  70   while (StaticList)
  71     StaticList->destroy();
  72
  73   if (llvm_is_multithreaded()) llvm_stop_multithreaded();
  74 }
  75