1 files changed, 25 insertions, 3 deletions
diff --git a/llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h b/llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
index 63ff00afc2ae..ababa1d61f66 100644
--- a/llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
+++ b/llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
@@ -62,6 +62,8 @@ public:
   typedef std::function<void(const PassManagerBuilder &Builder,
                              legacy::PassManagerBase &PM)>
       ExtensionFn;
+  typedef int GlobalExtensionID;
+
   enum ExtensionPointTy {
     /// EP_EarlyAsPossible - This extension point allows adding passes before
     /// any other transformations, allowing them to see the code as it is coming
@@ -193,7 +195,17 @@ public:
   /// Adds an extension that will be used by all PassManagerBuilder instances.
   /// This is intended to be used by plugins, to register a set of
   /// optimisations to run automatically.
-  static void addGlobalExtension(ExtensionPointTy Ty, ExtensionFn Fn);
+  ///
+  /// \returns A global extension identifier that can be used to remove the
+  /// extension.
+  static GlobalExtensionID addGlobalExtension(ExtensionPointTy Ty,
+                                              ExtensionFn Fn);
+  /// Removes an extension that was previously added using addGlobalExtension.
+  /// This is also intended to be used by plugins, to remove any extension that
+  /// was previously registered before being unloaded.
+  ///
+  /// \param ExtensionID Identifier of the extension to be removed.
+  static void removeGlobalExtension(GlobalExtensionID ExtensionID);
   void addExtension(ExtensionPointTy Ty, ExtensionFn Fn);
 
 private:
@@ -222,10 +234,20 @@ public:
 /// used by optimizer plugins to allow all front ends to transparently use
 /// them.  Create a static instance of this class in your plugin, providing a
 /// private function that the PassManagerBuilder can use to add your passes.
-struct RegisterStandardPasses {
+class RegisterStandardPasses {
+  PassManagerBuilder::GlobalExtensionID ExtensionID;
+
+public:
   RegisterStandardPasses(PassManagerBuilder::ExtensionPointTy Ty,
                          PassManagerBuilder::ExtensionFn Fn) {
-    PassManagerBuilder::addGlobalExtension(Ty, std::move(Fn));
+    ExtensionID = PassManagerBuilder::addGlobalExtension(Ty, std::move(Fn));
+  }
+
+  ~RegisterStandardPasses() {
+    // If the collection holding the global extensions is destroyed after the
+    // plugin is unloaded, the extension has to be removed here. Indeed, the
+    // destructor of the ExtensionFn may reference code in the plugin.
+    PassManagerBuilder::removeGlobalExtension(ExtensionID);
   }
 };