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Introduce safe_as_a

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gcc/
2014-08-18  David Malcolm  <dmalcolm@redhat.com>

	* is-a.h (template<T, U> safe_as_a <U *p>) New function.

From-SVN: r214117
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David Malcolm 2014-08-18 19:50:38 +00:00 • committed by David Malcolm
parent c41b94cef2
commit 26b3538ba2
2 changed files with 28 additions and 0 deletions
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gcc/ChangeLog
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@ -1,3 +1,7 @@
2014-08-18 David Malcolm <dmalcolm@redhat.com>
* is-a.h (template<T, U> safe_as_a <U *p>) New function.
2014-08-18 Jan Hubicka <hubicka@ucw.cz>
* ipa-visibility.c (update_visibility_by_resolution_info): Do no turn UNDEF

24
gcc/is-a.h
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@ -46,6 +46,14 @@ TYPE as_a <TYPE> (pointer)
do_something_with (as_a <cgraph_node *> *ptr);
TYPE safe_as_a <TYPE> (pointer)
Like as_a <TYPE> (pointer), but where pointer could be NULL. This
adds a check against NULL where the regular is_a_helper hook for TYPE
assumes non-NULL.
do_something_with (safe_as_a <cgraph_node *> *ptr);
TYPE dyn_cast <TYPE> (pointer)
Converts pointer to TYPE if and only if "is_a <TYPE> pointer". Otherwise,
@ -185,6 +193,22 @@ as_a (U *p)
return is_a_helper <T>::cast (p);
}
/* Similar to as_a<>, but where the pointer can be NULL, even if
is_a_helper<T> doesn't check for NULL. */
template <typename T, typename U>
inline T
safe_as_a (U *p)
{
if (p)
{
gcc_checking_assert (is_a <T> (p));
return is_a_helper <T>::cast (p);
}
else
return NULL;
}
/* A generic checked conversion from a base type U to a derived type T. See
the discussion above for when to use this function. */