[PATCH] Fix memory leak in lib/Support/DynamicLibrary.cpp wrap OpenedHandles in llvm::ManagedStatic<>

[Pavel Karneliuk]

Hi chandlerc, Bigcheese,

This patch fixes a memory leak in Support library.  Currently, the OpenedHandles is allocated dynamically and never deallocated. This patch wraps a raw pointer in llvm::ManagedStatic<> template. So, the registry of open handles will be managed by LLVM routines for static variables (llvm::llvm_shutdown()).

This patch is close to that https://github.com/llvm-mirror/llvm/commit/b4b9b3b24c03f414c54f55e1b34b4d9124c55883 patch.
I have removed fixme-message in the header.

http://reviews.llvm.org/D8838

Files:
  lib/Support/DynamicLibrary.cpp
  lib/Support/Windows/DynamicLibrary.inc

Index: lib/Support/DynamicLibrary.cpp
===================================================================
--- lib/Support/DynamicLibrary.cpp
+++ lib/Support/DynamicLibrary.cpp
@@ -9,8 +9,6 @@
 //
 //  This file implements the operating system DynamicLibrary concept.
 //
-// FIXME: This file leaks ExplicitSymbols and OpenedHandles!
-//
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/DynamicLibrary.h"
@@ -51,7 +49,7 @@
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
-static DenseSet<void *> *OpenedHandles = nullptr;
+static llvm::ManagedStatic<DenseSet<void *> > OpenedHandles;
 
 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
                                                    std::string *errMsg) {
@@ -70,9 +68,6 @@
     handle = RTLD_DEFAULT;
 #endif
 
-  if (!OpenedHandles)
-    OpenedHandles = new DenseSet<void *>();
-
   // If we've already loaded this library, dlclose() the handle in order to
   // keep the internal refcount at +1.
   if (!OpenedHandles->insert(handle).second)
@@ -121,7 +116,7 @@
 
 #if HAVE_DLFCN_H
   // Now search the libraries.
-  if (OpenedHandles) {
+  if (OpenedHandles.isConstructed()) {
     for (DenseSet<void *>::iterator I = OpenedHandles->begin(),
          E = OpenedHandles->end(); I != E; ++I) {
       //lt_ptr ptr = lt_dlsym(*I, symbolName);
Index: lib/Support/Windows/DynamicLibrary.inc
===================================================================
--- lib/Support/Windows/DynamicLibrary.inc
+++ lib/Support/Windows/DynamicLibrary.inc
@@ -39,7 +39,7 @@
 //===          and must not be UNIX code.
 //===----------------------------------------------------------------------===//
 
-static DenseSet<HMODULE> *OpenedHandles;
+static llvm::ManagedStatic<DenseSet<HMODULE> > OpenedHandles;
 
 static BOOL CALLBACK
 ELM_Callback(WIN32_ELMCB_PCSTR ModuleName, ULONG_PTR ModuleBase,
@@ -54,8 +54,6 @@
 
   if (!filename) {
     // When no file is specified, enumerate all DLLs and EXEs in the process.
-    if (OpenedHandles == 0)
-      OpenedHandles = new DenseSet<HMODULE>();
 
     EnumerateLoadedModules(GetCurrentProcess(), ELM_Callback, 0);
     // Dummy library that represents "search all handles".
@@ -77,9 +75,6 @@
     return DynamicLibrary();
   }
 
-  if (OpenedHandles == 0)
-    OpenedHandles = new DenseSet<HMODULE>();
-
   // If we've already loaded this library, FreeLibrary() the handle in order to
   // keep the internal refcount at +1.
   if (!OpenedHandles->insert(a_handle).second)
@@ -125,7 +120,7 @@
   }
 
   // Now search the libraries.
-  if (OpenedHandles) {
+  if (OpenedHandles.isConstructed()) {
     for (DenseSet<HMODULE>::iterator I = OpenedHandles->begin(),
          E = OpenedHandles->end(); I != E; ++I) {
       FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);

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