From: John McCall <rjmccall@apple.com>
Date: Tue, 13 Jul 2010 23:19:49 +0000 (+0000)
Subject: Work around an obnoxious GCC warning by changing semantics in a hopefully-
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3e29f96988b0438e42dba3790f61fb3df42d90cb;p=clang

Work around an obnoxious GCC warning by changing semantics in a hopefully-
harmless way.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108295 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index bfe00ea158..4980aad1b3 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -1541,4 +1541,6 @@ CodeGenFunction::CleanupBlock::~CleanupBlock() {
   CGF.Builder.restoreIP(SavedIP);
 }
 
-void EHScopeStack::LazyCleanup::_anchor() {}
+EHScopeStack::LazyCleanup::~LazyCleanup() {
+  llvm_unreachable("LazyCleanup is indestructable");
+}
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 90a5421c69..5ee3db08ee 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -125,18 +125,23 @@ public:
     }
   };
 
-  /// A lazy cleanup.  These will be allocated on the cleanup stack
-  /// and so must be trivially copyable.  We "enforce" this by
-  /// providing no virtual destructor so that subclasses will be
-  /// encouraged to contain no non-POD types.
+  /// A lazy cleanup.  Subclasses must be POD-like:  cleanups will
+  /// not be destructed, and they will be allocated on the cleanup
+  /// stack and freely copied and moved around.
   ///
   /// LazyCleanup implementations should generally be declared in an
   /// anonymous namespace.
   class LazyCleanup {
-    // Anchor the construction vtable.
-    virtual void _anchor();
-
   public:
+    // Anchor the construction vtable.  We use the destructor because
+    // gcc gives an obnoxious warning if there are virtual methods
+    // with an accessible non-virtual destructor.  Unfortunately,
+    // declaring this destructor makes it non-trivial, but there
+    // doesn't seem to be any other way around this warning.
+    //
+    // This destructor will never be called.
+    virtual ~LazyCleanup();
+
     /// Emit the cleanup.  For normal cleanups, this is run in the
     /// same EH context as when the cleanup was pushed, i.e. the
     /// immediately-enclosing context of the cleanup scope.  For