new helper class to provide more explicit management of static ctor/dtors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30638 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/ManagedStatic.cpp

@@ -0,0 +1,53 @@
+//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and 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 <cassert>
+using namespace llvm;
+
+static const ManagedStaticBase *StaticList = 0;
+
+void ManagedStaticBase::RegisterManagedStatic(void *ObjPtr,
+                                              void (*Deleter)(void*)) const {
+  assert(Ptr == 0 && DeleterFn == 0 && Next == 0 &&
+         "Partially init static?");
+  Ptr = ObjPtr;
+  DeleterFn = Deleter;
+  
+  // Add to list of managed statics.
+  Next = StaticList;
+  StaticList = this;
+}
+
+void ManagedStaticBase::destroy() const {
+  assert(Ptr && 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_shutdown() {
+  while (StaticList)
+    StaticList->destroy();
+}
+