diff lib/Support/ManagedStatic.cpp @ 0:95c75e76d11b

LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
parents
children 54457678186b
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Support/ManagedStatic.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,81 @@
+//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
+//
+//                     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 ManagedStatic class and llvm_shutdown().
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Atomic.h"
+#include <cassert>
+using namespace llvm;
+
+static const ManagedStaticBase *StaticList = 0;
+
+void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
+                                              void (*Deleter)(void*)) const {
+  if (llvm_is_multithreaded()) {
+    llvm_acquire_global_lock();
+
+    if (Ptr == 0) {
+      void* tmp = Creator ? Creator() : 0;
+
+      TsanHappensBefore(this);
+      sys::MemoryFence();
+
+      // This write is racy against the first read in the ManagedStatic
+      // accessors. The race is benign because it does a second read after a
+      // memory fence, at which point it isn't possible to get a partial value.
+      TsanIgnoreWritesBegin();
+      Ptr = tmp;
+      TsanIgnoreWritesEnd();
+      DeleterFn = Deleter;
+      
+      // Add to list of managed statics.
+      Next = StaticList;
+      StaticList = this;
+    }
+
+    llvm_release_global_lock();
+  } else {
+    assert(Ptr == 0 && DeleterFn == 0 && Next == 0 &&
+           "Partially initialized ManagedStatic!?");
+    Ptr = Creator ? Creator() : 0;
+    DeleterFn = Deleter;
+  
+    // Add to list of managed statics.
+    Next = StaticList;
+    StaticList = this;
+  }
+}
+
+void ManagedStaticBase::destroy() const {
+  assert(DeleterFn && "ManagedStatic not initialized correctly!");
+  assert(StaticList == this &&
+         "Not destroyed in reverse order of construction?");
+  // Unlink from list.
+  StaticList = Next;
+  Next = 0;
+
+  // Destroy memory.
+  DeleterFn(Ptr);
+  
+  // Cleanup.
+  Ptr = 0;
+  DeleterFn = 0;
+}
+
+/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
+void llvm::llvm_shutdown() {
+  while (StaticList)
+    StaticList->destroy();
+
+  if (llvm_is_multithreaded()) llvm_stop_multithreaded();
+}