Revise the implementation logic of sized deallocation: Do not automatically generate weak definitions of the sized operator delete (in terms of unsized operator delete). Instead, provide the funcitonality via a new compiler flag, -fdef-sized-delete.

The current implementation causes link-time ODR violations when the delete symbols are exported into the dynamic table.

llvm-svn: 229241

clang/lib/CodeGen/CodeGenModule.cpp

@@ -1615,13 +1615,13 @@ CodeGenModule::GetOrCreateLLVMFunction(StringRef MangledName,
       // don't need it anymore).
       addDeferredDeclToEmit(F, DDI->second);
       DeferredDecls.erase(DDI);
-
+      
       // Otherwise, if this is a sized deallocation function, emit a weak
-      // definition
-      // for it at the end of the translation unit.
+      // definition for it at the end of the translation unit.
     } else if (D && cast<FunctionDecl>(D)
                         ->getCorrespondingUnsizedGlobalDeallocationFunction()) {
-      addDeferredDeclToEmit(F, GD);
+      if (getLangOpts().DefaultSizedDelete)
+        addDeferredDeclToEmit(F, GD);
 
       // Otherwise, there are cases we have to worry about where we're
       // using a declaration for which we must emit a definition but where