From: Argyrios Kyrtzidis Date: Fri, 7 Aug 2009 22:49:24 +0000 (+0000) Subject: Modifications to dyn_cast/cast to make them work for objects too, instead of only... X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8b6d86df062f9402c0cde66eb6c7013afb414285;p=oota-llvm.git Modifications to dyn_cast/cast to make them work for objects too, instead of only pointers. The use case is if you have a wrapper class: class Base { void *Ptr; public: Base() : Ptr(0) { } operator bool() const { return Ptr; } ..... } and sub-wrappers that have exactly the same size: class Sub : public Base { public: .... static bool classof(const Base*); } and in the code you would do: void f(Base b) { Sub sub = dyn_cast(b); if (sub) { .... } } git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78424 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h index 48988f8a6bb..353611fc121 100644 --- a/include/llvm/Support/Casting.h +++ b/include/llvm/Support/Casting.h @@ -205,8 +205,9 @@ inline typename cast_retty::ret_type cast(const Y &Val) { // accepted. // template -inline typename cast_retty::ret_type cast_or_null(Y *Val) { - if (Val == 0) return 0; +inline typename cast_retty::ret_type cast_or_null(const Y &Val) { + typedef typename cast_retty::ret_type ret_type; + if (!Val) return ret_type(); assert(isa(Val) && "cast_or_null() argument of incompatible type!"); return cast(Val); } @@ -222,7 +223,8 @@ inline typename cast_retty::ret_type cast_or_null(Y *Val) { template inline typename cast_retty::ret_type dyn_cast(const Y &Val) { - return isa(Val) ? cast(Val) : 0; + typedef typename cast_retty::ret_type ret_type; + return isa(Val) ? cast(Val) : (ret_type)ret_type(); } // dyn_cast_or_null - Functionally identical to dyn_cast, except that a null @@ -230,7 +232,8 @@ inline typename cast_retty::ret_type dyn_cast(const Y &Val) { // template inline typename cast_retty::ret_type dyn_cast_or_null(const Y &Val) { - return (Val && isa(Val)) ? cast(Val) : 0; + typedef typename cast_retty::ret_type ret_type; + return (Val && isa(Val)) ? cast(Val) : (ret_type)ret_type(); }