Casting.h revision f5091b476c46333ecfcf095cd2e422e9748e9546
18a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===-- llvm/Support/Casting.h - Allow flexible, checked, casts -*- C++ -*-===// 28a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 38a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// The LLVM Compiler Infrastructure 48a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 58a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// This file is distributed under the University of Illinois Open Source 68a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// License. See LICENSE.TXT for details. 78a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 88a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===----------------------------------------------------------------------===// 98a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 108a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// This file defines the isa<X>(), cast<X>(), dyn_cast<X>(), cast_or_null<X>(), 118a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// and dyn_cast_or_null<X>() templates. 128a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 138a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===----------------------------------------------------------------------===// 148a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 158a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen#ifndef LLVM_SUPPORT_CASTING_H 168a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen#define LLVM_SUPPORT_CASTING_H 178a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 188a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen#include <cassert> 198a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 208a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chennamespace llvm { 218a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 228a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===----------------------------------------------------------------------===// 238a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// isa<x> Support Templates 248a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===----------------------------------------------------------------------===// 258a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 268a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// Define a template that can be specialized by smart pointers to reflect the 278a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// fact that they are automatically dereferenced, and are not involved with the 288a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// template selection process... the default implementation is a noop. 298a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 308a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<typename From> struct simplify_type { 318a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef From SimpleType; // The real type this represents... 328a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 338a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // An accessor to get the real value... 348a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static SimpleType &getSimplifiedValue(From &Val) { return Val; } 358a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 368a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 378a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<typename From> struct simplify_type<const From> { 388a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef const From SimpleType; 398a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static SimpleType &getSimplifiedValue(const From &Val) { 408a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return simplify_type<From>::getSimplifiedValue(static_cast<From&>(Val)); 418a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 428a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 438a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 448a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// The core of the implementation of isa<X> is here; To and From should be 458a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// the names of classes. This template can be specialized to customize the 468a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// implementation of isa<> without rewriting it from scratch. 478a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <typename To, typename From> 488a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chenstruct isa_impl { 498a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static inline bool doit(const From &Val) { 508a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return To::classof(&Val); 518a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 528a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 538a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 548a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <typename To, typename From> struct isa_impl_cl { 558a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static inline bool doit(const From &Val) { 568a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl<To, From>::doit(Val); 578a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 588a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 598a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 608a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <typename To, typename From> struct isa_impl_cl<To, const From> { 618a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static inline bool doit(const From &Val) { 628a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl<To, From>::doit(Val); 638a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 648a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 658a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 668a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <typename To, typename From> struct isa_impl_cl<To, From*> { 678a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static inline bool doit(const From *Val) { 688a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen assert(Val && "isa<> used on a null pointer"); 698a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl<To, From>::doit(*Val); 708a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 718a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 728a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 738a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <typename To, typename From> struct isa_impl_cl<To, const From*> { 748a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static inline bool doit(const From *Val) { 758a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen assert(Val && "isa<> used on a null pointer"); 768a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl<To, From>::doit(*Val); 778a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 788a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 798a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 808a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <typename To, typename From> struct isa_impl_cl<To, const From*const> { 818a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static inline bool doit(const From *Val) { 828a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen assert(Val && "isa<> used on a null pointer"); 838a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl<To, From>::doit(*Val); 848a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 858a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 868a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 878a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<typename To, typename From, typename SimpleFrom> 888a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chenstruct isa_impl_wrap { 898a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // When From != SimplifiedType, we can simplify the type some more by using 908a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // the simplify_type template. 918a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static bool doit(const From &Val) { 928a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl_wrap<To, SimpleFrom, 938a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typename simplify_type<SimpleFrom>::SimpleType>::doit( 948a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen simplify_type<From>::getSimplifiedValue(Val)); 958a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 968a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 978a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 988a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<typename To, typename FromTy> 998a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chenstruct isa_impl_wrap<To, FromTy, FromTy> { 1008a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // When From == SimpleType, we are as simple as we are going to get. 1018a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static bool doit(const FromTy &Val) { 1028a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl_cl<To,FromTy>::doit(Val); 1038a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 1048a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1058a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1068a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// isa<X> - Return true if the parameter to the template is an instance of the 1078a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// template type argument. Used like this: 1088a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 1098a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// if (isa<Type>(myVal)) { ... } 1108a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 1118a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <class X, class Y> 1128a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Cheninline bool isa(const Y &Val) { 1138a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa_impl_wrap<X, Y, typename simplify_type<Y>::SimpleType>::doit(Val); 1148a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen} 1158a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1168a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===----------------------------------------------------------------------===// 1178a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// cast<x> Support Templates 1188a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen//===----------------------------------------------------------------------===// 1198a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1208a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> struct cast_retty; 1218a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1228a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1238a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// Calculate what type the 'cast' function should return, based on a requested 1248a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// type of To and a source type of From. 1258a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> struct cast_retty_impl { 1268a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef To& ret_type; // Normal case, return Ty& 1278a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1288a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> struct cast_retty_impl<To, const From> { 1298a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef const To &ret_type; // Normal case, return Ty& 1308a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1318a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1328a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> struct cast_retty_impl<To, From*> { 1338a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef To* ret_type; // Pointer arg case, return Ty* 1348a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1358a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1368a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> struct cast_retty_impl<To, const From*> { 1378a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef const To* ret_type; // Constant pointer arg case, return const Ty* 1388a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1398a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1408a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> struct cast_retty_impl<To, const From*const> { 1418a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef const To* ret_type; // Constant pointer arg case, return const Ty* 1428a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1438a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1448a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1458a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From, class SimpleFrom> 1468a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chenstruct cast_retty_wrap { 1478a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // When the simplified type and the from type are not the same, use the type 1488a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // simplifier to reduce the type, then reuse cast_retty_impl to get the 1498a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // resultant type. 1508a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef typename cast_retty<To, SimpleFrom>::ret_type ret_type; 1518a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1528a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1538a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class FromTy> 1548a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chenstruct cast_retty_wrap<To, FromTy, FromTy> { 1558a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // When the simplified type is equal to the from type, use it directly. 1568a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef typename cast_retty_impl<To,FromTy>::ret_type ret_type; 1578a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1588a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1598a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From> 1608a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chenstruct cast_retty { 1618a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typedef typename cast_retty_wrap<To, From, 1628a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typename simplify_type<From>::SimpleType>::ret_type ret_type; 1638a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1648a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1658a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// Ensure the non-simple values are converted using the simplify_type template 1668a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// that may be specialized by smart pointers... 1678a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 1688a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class From, class SimpleFrom> struct cast_convert_val { 1698a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // This is not a simple type, use the template to simplify it... 1708a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static typename cast_retty<To, From>::ret_type doit(const From &Val) { 1718a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return cast_convert_val<To, SimpleFrom, 1728a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typename simplify_type<SimpleFrom>::SimpleType>::doit( 1738a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen simplify_type<From>::getSimplifiedValue(Val)); 1748a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 1758a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1768a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1778a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> { 1788a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen // This _is_ a simple type, just cast it. 1798a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) { 1808a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typename cast_retty<To, FromTy>::ret_type Res2 1818a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen = (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val); 1828a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return Res2; 1838a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen } 1848a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen}; 1858a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1868a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1878a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 1888a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// cast<X> - Return the argument parameter cast to the specified type. This 1898a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// casting operator asserts that the type is correct, so it does not return null 1908a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// on failure. It does not allow a null argument (use cast_or_null for that). 1918a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// It is typically used like this: 1928a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 1938a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// cast<Instruction>(myVal)->getParent() 1948a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 1958a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <class X, class Y> 1968a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Cheninline typename cast_retty<X, Y>::ret_type cast(const Y &Val) { 1978a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!"); 1988a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return cast_convert_val<X, Y, 1998a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen typename simplify_type<Y>::SimpleType>::doit(Val); 2008a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen} 2018a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2028a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// cast_or_null<X> - Functionally identical to cast, except that a null value is 2038a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// accepted. 2048a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 2058a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <class X, class Y> 2068a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Cheninline typename cast_retty<X, Y*>::ret_type cast_or_null(Y *Val) { 2078a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen if (Val == 0) return 0; 2088a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!"); 2098a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return cast<X>(Val); 2108a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen} 2118a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2128a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2138a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// dyn_cast<X> - Return the argument parameter cast to the specified type. This 2148a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// casting operator returns null if the argument is of the wrong type, so it can 2158a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// be used to test for a type as well as cast if successful. This should be 2168a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// used in the context of an if statement like this: 2178a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 2188a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// if (const Instruction *I = dyn_cast<Instruction>(myVal)) { ... } 2198a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 2208a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2218a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <class X, class Y> 2228a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Cheninline typename cast_retty<X, Y>::ret_type dyn_cast(const Y &Val) { 2238a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return isa<X>(Val) ? cast<X, Y>(Val) : 0; 2248a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen} 2258a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2268a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null 2278a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// value is accepted. 2288a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen// 2298a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chentemplate <class X, class Y> 2308a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Cheninline typename cast_retty<X, Y*>::ret_type dyn_cast_or_null(Y *Val) { 2318a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen return (Val && isa<X>(Val)) ? cast<X>(Val) : 0; 2328a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen} 2338a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2348a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen} // End llvm namespace 2358a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen 2368a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen#endif 2378a3c0430323c28c1fbe8ceecd2cd8e58b64a9295Johnny Chen