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Modifications to dyn_cast/cast to make them work for objects too, instead of only pointers.

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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<Sub>(b);
  if (sub) {
    ....
  }
}



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78424 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Argyrios Kyrtzidis 2009-08-07 22:49:24 +00:00
parent c114ed711e
commit 8b6d86df06
1 changed files with 7 additions and 4 deletions
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11
include/llvm/Support/Casting.h
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@ -205,8 +205,9 @@ inline typename cast_retty<X, Y>::ret_type cast(const Y &Val) {
// accepted.
//
template <class X, class Y>
inline typename cast_retty<X, Y*>::ret_type cast_or_null(Y *Val) {
if (Val == 0) return 0;
inline typename cast_retty<X, Y>::ret_type cast_or_null(const Y &Val) {
typedef typename cast_retty<X, Y>::ret_type ret_type;
if (!Val) return ret_type();
assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!");
return cast<X>(Val);
}
@ -222,7 +223,8 @@ inline typename cast_retty<X, Y*>::ret_type cast_or_null(Y *Val) {
template <class X, class Y>
inline typename cast_retty<X, Y>::ret_type dyn_cast(const Y &Val) {
return isa<X>(Val) ? cast<X, Y>(Val) : 0;
typedef typename cast_retty<X, Y>::ret_type ret_type;
return isa<X>(Val) ? cast<X, Y>(Val) : (ret_type)ret_type();
}
// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
@ -230,7 +232,8 @@ inline typename cast_retty<X, Y>::ret_type dyn_cast(const Y &Val) {
//
template <class X, class Y>
inline typename cast_retty<X, Y>::ret_type dyn_cast_or_null(const Y &Val) {
return (Val && isa<X>(Val)) ? cast<X, Y>(Val) : 0;
typedef typename cast_retty<X, Y>::ret_type ret_type;
return (Val && isa<X>(Val)) ? cast<X, Y>(Val) : (ret_type)ret_type();
}