-//===-- Support/Casting.h - Allow flexible, checked, casts -------*- C++ -*--=//
+//===-- llvm/Support/Casting.h - Allow flexible, checked, casts -*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// This file defines the isa<X>(), cast<X>(), dyn_cast<X>(), cast_or_null<X>(),
// and dyn_cast_or_null<X>() templates.
//
//===----------------------------------------------------------------------===//
-#ifndef SUPPORT_CASTING_H
-#define SUPPORT_CASTING_H
+#ifndef LLVM_SUPPORT_CASTING_H
+#define LLVM_SUPPORT_CASTING_H
+
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/type_traits.h"
+#include <cassert>
-#include <assert.h>
+namespace llvm {
//===----------------------------------------------------------------------===//
// isa<x> Support Templates
//===----------------------------------------------------------------------===//
-template<typename FromCl> struct isa_impl_cl;
-
// Define a template that can be specialized by smart pointers to reflect the
// fact that they are automatically dereferenced, and are not involved with the
// template selection process... the default implementation is a noop.
};
template<typename From> struct simplify_type<const From> {
- typedef const From SimpleType;
- static SimpleType &getSimplifiedValue(const From &Val) {
- return simplify_type<From>::getSimplifiedValue((From&)Val);
+ typedef typename simplify_type<From>::SimpleType NonConstSimpleType;
+ typedef typename add_const_past_pointer<NonConstSimpleType>::type
+ SimpleType;
+ typedef typename add_lvalue_reference_if_not_pointer<SimpleType>::type
+ RetType;
+ static RetType getSimplifiedValue(const From& Val) {
+ return simplify_type<From>::getSimplifiedValue(const_cast<From&>(Val));
}
};
+// The core of the implementation of isa<X> is here; To and From should be
+// the names of classes. This template can be specialized to customize the
+// implementation of isa<> without rewriting it from scratch.
+template <typename To, typename From, typename Enabler = void>
+struct isa_impl {
+ static inline bool doit(const From &Val) {
+ return To::classof(&Val);
+ }
+};
-// isa<X> - Return true if the parameter to the template is an instance of the
-// template type argument. Used like this:
-//
-// if (isa<Type*>(myVal)) { ... }
-//
+/// \brief Always allow upcasts, and perform no dynamic check for them.
template <typename To, typename From>
-inline bool isa_impl(const From &Val) {
- return To::classof(&Val);
-}
+struct isa_impl<
+ To, From, typename std::enable_if<std::is_base_of<To, From>::value>::type> {
+ static inline bool doit(const From &) { return true; }
+};
-template<typename To, typename From, typename SimpleType>
-struct isa_impl_wrap {
- // When From != SimplifiedType, we can simplify the type some more by using
- // the simplify_type template.
- static bool doit(const From &Val) {
- return isa_impl_cl<const SimpleType>::template
- isa<To>(simplify_type<const From>::getSimplifiedValue(Val));
+template <typename To, typename From> struct isa_impl_cl {
+ static inline bool doit(const From &Val) {
+ return isa_impl<To, From>::doit(Val);
}
};
-template<typename To, typename FromTy>
-struct isa_impl_wrap<To, const FromTy, const FromTy> {
- // When From == SimpleType, we are as simple as we are going to get.
- static bool doit(const FromTy &Val) {
- return isa_impl<To,FromTy>(Val);
+template <typename To, typename From> struct isa_impl_cl<To, const From> {
+ static inline bool doit(const From &Val) {
+ return isa_impl<To, From>::doit(Val);
}
};
-// isa_impl_cl - Use class partial specialization to transform types to a single
-// cannonical form for isa_impl.
-//
-template<typename FromCl>
-struct isa_impl_cl {
- template<class ToCl>
- static bool isa(const FromCl &Val) {
- return isa_impl_wrap<ToCl,const FromCl,
- typename simplify_type<const FromCl>::SimpleType>::doit(Val);
+template <typename To, typename From> struct isa_impl_cl<To, From*> {
+ static inline bool doit(const From *Val) {
+ assert(Val && "isa<> used on a null pointer");
+ return isa_impl<To, From>::doit(*Val);
+ }
+};
+
+template <typename To, typename From> struct isa_impl_cl<To, From*const> {
+ static inline bool doit(const From *Val) {
+ assert(Val && "isa<> used on a null pointer");
+ return isa_impl<To, From>::doit(*Val);
}
};
-// Specialization used to strip const qualifiers off of the FromCl type...
-template<typename FromCl>
-struct isa_impl_cl<const FromCl> {
- template<class ToCl>
- static bool isa(const FromCl &Val) {
- return isa_impl_cl<FromCl>::template isa<ToCl>(Val);
+template <typename To, typename From> struct isa_impl_cl<To, const From*> {
+ static inline bool doit(const From *Val) {
+ assert(Val && "isa<> used on a null pointer");
+ return isa_impl<To, From>::doit(*Val);
}
};
-// Define pointer traits in terms of base traits...
-template<class FromCl>
-struct isa_impl_cl<FromCl*> {
- template<class ToCl>
- static bool isa(FromCl *Val) {
- return isa_impl_cl<FromCl>::template isa<ToCl>(*Val);
+template <typename To, typename From> struct isa_impl_cl<To, const From*const> {
+ static inline bool doit(const From *Val) {
+ assert(Val && "isa<> used on a null pointer");
+ return isa_impl<To, From>::doit(*Val);
}
};
-// Define reference traits in terms of base traits...
-template<class FromCl>
-struct isa_impl_cl<FromCl&> {
- template<class ToCl>
- static bool isa(FromCl &Val) {
- return isa_impl_cl<FromCl>::template isa<ToCl>(&Val);
+template<typename To, typename From, typename SimpleFrom>
+struct isa_impl_wrap {
+ // When From != SimplifiedType, we can simplify the type some more by using
+ // the simplify_type template.
+ static bool doit(const From &Val) {
+ return isa_impl_wrap<To, SimpleFrom,
+ typename simplify_type<SimpleFrom>::SimpleType>::doit(
+ simplify_type<const From>::getSimplifiedValue(Val));
}
};
+template<typename To, typename FromTy>
+struct isa_impl_wrap<To, FromTy, FromTy> {
+ // When From == SimpleType, we are as simple as we are going to get.
+ static bool doit(const FromTy &Val) {
+ return isa_impl_cl<To,FromTy>::doit(Val);
+ }
+};
+
+// isa<X> - Return true if the parameter to the template is an instance of the
+// template type argument. Used like this:
+//
+// if (isa<Type>(myVal)) { ... }
+//
template <class X, class Y>
-inline bool isa(const Y &Val) {
- return isa_impl_cl<Y>::template isa<X>(Val);
+LLVM_ATTRIBUTE_UNUSED_RESULT inline bool isa(const Y &Val) {
+ return isa_impl_wrap<X, const Y,
+ typename simplify_type<const Y>::SimpleType>::doit(Val);
}
//===----------------------------------------------------------------------===//
template<class To, class From>
struct cast_retty {
- typedef typename cast_retty_wrap<To, From,
+ typedef typename cast_retty_wrap<To, From,
typename simplify_type<From>::SimpleType>::ret_type ret_type;
};
//
template<class To, class From, class SimpleFrom> struct cast_convert_val {
// This is not a simple type, use the template to simplify it...
- static typename cast_retty<To, From>::ret_type doit(const From &Val) {
+ static typename cast_retty<To, From>::ret_type doit(From &Val) {
return cast_convert_val<To, SimpleFrom,
typename simplify_type<SimpleFrom>::SimpleType>::doit(
simplify_type<From>::getSimplifiedValue(Val));
template<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> {
// This _is_ a simple type, just cast it.
static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) {
- return (typename cast_retty<To, FromTy>::ret_type)Val;
+ typename cast_retty<To, FromTy>::ret_type Res2
+ = (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val);
+ return Res2;
}
};
-
+template <class X> struct is_simple_type {
+ static const bool value =
+ std::is_same<X, typename simplify_type<X>::SimpleType>::value;
+};
// cast<X> - Return the argument parameter cast to the specified type. This
// casting operator asserts that the type is correct, so it does not return null
-// on failure. But it will correctly return NULL when the input is NULL.
-// Used Like this:
+// on failure. It does not allow a null argument (use cast_or_null for that).
+// It is typically used like this:
//
// cast<Instruction>(myVal)->getParent()
//
template <class X, class Y>
-inline typename cast_retty<X, Y>::ret_type cast(const Y &Val) {
- assert(isa<X>(Val) && "cast<Ty>() argument of uncompatible type!");
+inline typename std::enable_if<!is_simple_type<Y>::value,
+ typename cast_retty<X, const Y>::ret_type>::type
+cast(const Y &Val) {
+ assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
+ return cast_convert_val<
+ X, const Y, typename simplify_type<const Y>::SimpleType>::doit(Val);
+}
+
+template <class X, class Y>
+inline typename cast_retty<X, Y>::ret_type cast(Y &Val) {
+ assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
return cast_convert_val<X, Y,
typename simplify_type<Y>::SimpleType>::doit(Val);
}
+template <class X, class Y>
+inline typename cast_retty<X, Y *>::ret_type cast(Y *Val) {
+ assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
+ return cast_convert_val<X, Y*,
+ typename simplify_type<Y*>::SimpleType>::doit(Val);
+}
+
// cast_or_null<X> - Functionally identical to cast, except that a null value is
// accepted.
//
template <class X, class Y>
-inline typename cast_retty<X, Y*>::ret_type cast_or_null(Y *Val) {
- if (Val == 0) return 0;
- assert(isa<X>(Val) && "cast_or_null<Ty>() argument of uncompatible type!");
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
+cast_or_null(Y *Val) {
+ if (!Val) return nullptr;
+ assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!");
return cast<X>(Val);
}
// be used to test for a type as well as cast if successful. This should be
// used in the context of an if statement like this:
//
-// if (const Instruction *I = dyn_cast<const Instruction>(myVal)) { ... }
+// if (const Instruction *I = dyn_cast<Instruction>(myVal)) { ... }
//
template <class X, class Y>
-inline typename cast_retty<X, Y*>::ret_type dyn_cast(Y *Val) {
- return isa<X>(Val) ? cast<X, Y*>(Val) : 0;
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename std::enable_if<
+ !is_simple_type<Y>::value, typename cast_retty<X, const Y>::ret_type>::type
+dyn_cast(const Y &Val) {
+ return isa<X>(Val) ? cast<X>(Val) : nullptr;
}
-// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
-// value is accepted.
-//
template <class X, class Y>
-inline typename cast_retty<X, Y*>::ret_type dyn_cast_or_null(Y *Val) {
- return (Val && isa<X>(Val)) ? cast<X, Y*>(Val) : 0;
-}
-
-
-#ifdef DEBUG_CAST_OPERATORS
-#include <iostream>
-
-struct bar {
- bar() {}
-private:
- bar(const bar &);
-};
-struct foo {
- void ext() const;
- /* static bool classof(const bar *X) {
- cerr << "Classof: " << X << "\n";
- return true;
- }*/
-};
-
-template <> inline bool isa_impl<foo,bar>(const bar &Val) {
- cerr << "Classof: " << &Val << "\n";
- return true;
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y>::ret_type
+dyn_cast(Y &Val) {
+ return isa<X>(Val) ? cast<X>(Val) : nullptr;
}
-
-bar *fub();
-void test(bar &B1, const bar *B2) {
- // test various configurations of const
- const bar &B3 = B1;
- const bar *const B4 = B2;
-
- // test isa
- if (!isa<foo>(B1)) return;
- if (!isa<foo>(B2)) return;
- if (!isa<foo>(B3)) return;
- if (!isa<foo>(B4)) return;
-
- // test cast
- foo &F1 = cast<foo>(B1);
- const foo *F3 = cast<foo>(B2);
- const foo *F4 = cast<foo>(B2);
- const foo &F8 = cast<foo>(B3);
- const foo *F9 = cast<foo>(B4);
- foo *F10 = cast<foo>(fub());
-
- // test cast_or_null
- const foo *F11 = cast_or_null<foo>(B2);
- const foo *F12 = cast_or_null<foo>(B2);
- const foo *F13 = cast_or_null<foo>(B4);
- const foo *F14 = cast_or_null<foo>(fub()); // Shouldn't print.
-
- // These lines are errors...
- //foo *F20 = cast<foo>(B2); // Yields const foo*
- //foo &F21 = cast<foo>(B3); // Yields const foo&
- //foo *F22 = cast<foo>(B4); // Yields const foo*
- //foo &F23 = cast_or_null<foo>(B1);
- //const foo &F24 = cast_or_null<foo>(B3);
+template <class X, class Y>
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
+dyn_cast(Y *Val) {
+ return isa<X>(Val) ? cast<X>(Val) : nullptr;
}
-bar *fub() { return 0; }
-void main() {
- bar B;
- test(B, &B);
+// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
+// value is accepted.
+//
+template <class X, class Y>
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
+dyn_cast_or_null(Y *Val) {
+ return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr;
}
-#endif
+} // End llvm namespace
#endif
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