-//===-- 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
-// real_type - Provide a macro to get the real type of a value that might be
-// a use. This provides a typedef 'Type' that is the argument type for all
-// non UseTy types, and is the contained pointer type of the use if it is a
-// UseTy.
-//
-template <class X> class real_type { typedef X Type; };
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/type_traits.h"
+#include <cassert>
+
+namespace llvm {
//===----------------------------------------------------------------------===//
-// Type Checking Templates
+// isa<x> Support Templates
//===----------------------------------------------------------------------===//
+// 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 {
+ typedef From SimpleType; // The real type this represents...
+
+ // An accessor to get the real value...
+ static SimpleType &getSimplifiedValue(From &Val) { return Val; }
+};
+
+template<typename From> struct simplify_type<const From> {
+ 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);
+ }
+};
+
+/// \brief Always allow upcasts, and perform no dynamic check for them.
+template <typename To, typename From>
+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> struct isa_impl_cl {
+ static inline bool doit(const From &Val) {
+ return isa_impl<To, From>::doit(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);
+ }
+};
+
+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);
+ }
+};
+
+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);
+ }
+};
+
+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);
+ }
+};
+
+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(Y Val) {
- assert(Val && "isa<Ty>(NULL) invoked!");
- return X::classof(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);
}
+//===----------------------------------------------------------------------===//
+// cast<x> Support Templates
+//===----------------------------------------------------------------------===//
+
+template<class To, class From> struct cast_retty;
+
+
+// Calculate what type the 'cast' function should return, based on a requested
+// type of To and a source type of From.
+template<class To, class From> struct cast_retty_impl {
+ typedef To& ret_type; // Normal case, return Ty&
+};
+template<class To, class From> struct cast_retty_impl<To, const From> {
+ typedef const To &ret_type; // Normal case, return Ty&
+};
+
+template<class To, class From> struct cast_retty_impl<To, From*> {
+ typedef To* ret_type; // Pointer arg case, return Ty*
+};
+
+template<class To, class From> struct cast_retty_impl<To, const From*> {
+ typedef const To* ret_type; // Constant pointer arg case, return const Ty*
+};
+
+template<class To, class From> struct cast_retty_impl<To, const From*const> {
+ typedef const To* ret_type; // Constant pointer arg case, return const Ty*
+};
+
+
+template<class To, class From, class SimpleFrom>
+struct cast_retty_wrap {
+ // When the simplified type and the from type are not the same, use the type
+ // simplifier to reduce the type, then reuse cast_retty_impl to get the
+ // resultant type.
+ typedef typename cast_retty<To, SimpleFrom>::ret_type ret_type;
+};
+
+template<class To, class FromTy>
+struct cast_retty_wrap<To, FromTy, FromTy> {
+ // When the simplified type is equal to the from type, use it directly.
+ typedef typename cast_retty_impl<To,FromTy>::ret_type ret_type;
+};
+
+template<class To, class From>
+struct cast_retty {
+ typedef typename cast_retty_wrap<To, From,
+ typename simplify_type<From>::SimpleType>::ret_type ret_type;
+};
+
+// Ensure the non-simple values are converted using the simplify_type template
+// that may be specialized by smart pointers...
+//
+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(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) {
+ 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()
-// cast<const Instruction>(myVal)->getParent()
+// cast<Instruction>(myVal)->getParent()
//
template <class X, class Y>
-inline X *cast(Y Val) {
- assert(isa<X>(Val) && "cast<Ty>() argument of uncompatible type!");
- return (X*)(real_type<Y>::Type)Val;
+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 X *cast_or_null(Y Val) {
- assert((Val == 0 || isa<X>(Val)) &&
- "cast_or_null<Ty>() argument of uncompatible type!");
- return (X*)(real_type<Y>::Type)Val;
+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 X *dyn_cast(Y Val) {
- return isa<X>(Val) ? cast<X>(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;
+}
+
+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;
+}
+
+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;
}
// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
// value is accepted.
//
template <class X, class Y>
-inline X *dyn_cast_or_null(Y Val) {
- return (Val && isa<X>(Val)) ? cast<X>(Val) : 0;
+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;
}
+} // End llvm namespace
+
#endif
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