[llvm] r202609 - [C++11] Add support for OwningPtr<T> to be converted to and from

[Ahmed Charles]

________________________________
> Date: Sat, 1 Mar 2014 21:55:51 -0800 
> Subject: Re: [llvm] r202609 - [C++11] Add support for OwningPtr<T> to  
> be converted to and from 
> From: richard at metafoo.co.uk 
> To: chandlerc at gmail.com 
> CC: llvm-commits at cs.uiuc.edu 
>  
> On Sat, Mar 1, 2014 at 7:38 PM, Chandler Carruth  
> <chandlerc at gmail.com<mailto:chandlerc at gmail.com>> wrote: 
> Author: chandlerc 
> Date: Sat Mar  1 21:38:32 2014 
> New Revision: 202609 
>  
> URL: http://llvm.org/viewvc/llvm-project?rev=202609&view=rev 
> Log: 
> [C++11] Add support for OwningPtr<T> to be converted to and from 
> std::unique_ptr<T>. 
>  
> Patch by Ahmed Charles! 
>  
> Modified: 
>      llvm/trunk/include/llvm/ADT/OwningPtr.h 
>      llvm/trunk/unittests/ADT/OwningPtrTest.cpp 
>  
> Modified: llvm/trunk/include/llvm/ADT/OwningPtr.h 
> URL:  
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/OwningPtr.h?rev=202609&r1=202608&r2=202609&view=diff 
> ============================================================================== 
> --- llvm/trunk/include/llvm/ADT/OwningPtr.h (original) 
> +++ llvm/trunk/include/llvm/ADT/OwningPtr.h Sat Mar  1 21:38:32 2014 
> @@ -17,6 +17,7 @@ 
>   #include "llvm/Support/Compiler.h" 
>   #include <cassert> 
>   #include <cstddef> 
> +#include <memory> 
>  
>   namespace llvm { 
>  
> @@ -39,6 +40,17 @@ public: 
>       return *this; 
>     } 
>  
> +  OwningPtr(std::unique_ptr<T> &&Other) : Ptr(Other.release()) {} 
> + 
> +  OwningPtr &operator=(std::unique_ptr<T> &&Other) { 
>  
> Why an rvalue reference to a unique_ptr rather than passing the  
> unique_ptr by value? 

No particular reason, though I suppose it is one less write to memory if the optimizer can't remove it. I just didn't consider passing by value. Feel free to change, I don't have commit access yet.

> +    reset(Other.release()); 
> +    return *this; 
> +  } 
> + 
> +#if LLVM_HAS_RVALUE_REFERENCE_THIS 
> +  operator std::unique_ptr<T>() && { return std::unique_ptr<T>(take()); } 
> +#endif 
> + 
>     ~OwningPtr() { 
>       delete Ptr; 
>     } 
> @@ -61,6 +73,8 @@ public: 
>       return Tmp; 
>     } 
>  
> +  std::unique_ptr<T> take_unique() { return std::unique_ptr<T>(take()); } 
> + 
>     T &operator*() const { 
>       assert(Ptr && "Cannot dereference null pointer"); 
>       return *Ptr;